• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a two-stage pump (1) for a hydraulic system with a housing (2), a high and low pressure pump element, a common pressure output and a switching valve (6) disposed between a tank connection and the low pressure pump element. The switching valve (6) has a spring element (8) and a piston (9) movable relative to the housing (2) against the restoring force of the spring element (8) and having a closing member (10) that can be lifted from a valve seat (12) by a control pressure that is connected to the pressure outlet (5) and applied in a control pressure chamber (11). On the one hand, the invention is characterized in that the switching valve (6) comprises a pusher-valve (13) that can be moved relative to the housing (2) and configured to move the piston (9) and disposed between the chamber control pressure (11) and the piston (9) and has a smaller effective diameter than the piston (9). On the other hand, the invention is characterized in that the two-stage pump (1) comprises at least one valve (23, 25) that can be screwed into the housing (2), wherein a cutting lip (27) of the valve (23, 25) slides hermetically into the housing (2, 48).
    公开号:ES2685458A1
    申请号:ES201731471
    申请日:2017-12-26
    公开日:2018-10-09
    发明作者:Georg Neumair；Thomas Simon
    申请人:Hawe Hydraulik SE；
    IPC主号:
    专利说明:

    Two stage pump with switching valve
    Technical scope
    The present invention relates to a two stage pump for a hydraulic system with a housing, a high pressure pump element and a low pressure pump element, a common pressure outlet and a switching valve that is disposed between a Tank connection and the low pressure pump element and it is configured as a seat valve.
    Prior art
    Such double stage pumps are known in the prior art. For example, EP 2 634 426 A1 shows a two stage pump with such a switching valve. The switching valve is disposed in the housing and comprises a spring element and a piston that can move relative to the housing against the force of the spring element. The piston comprises a closing member that can be lifted from a valve seat by means of a control pressure that is connected to the pressure outlet and applied in a control pressure chamber, so that the switching valve is opened to the tank . The switching valve known from EP 2 634 426 A1 has a sleeve that is housed in the two-stage pump housing and has a valve seat on which the piston tapered seal element rests due to the force of the spring element. In addition, the piston comprises a skirt on the outer circumferential surface, of which the spring element in the form of a cup spring pad is arranged. On the one hand, the sleeve and in the direction of opening a spring support nut that is threaded into the piston skirt serves as a spring support. In addition, the two-stage pump comprises a pressure and suction valve each of which is assigned to the high pressure pump element and the low pressure pump element, where both pressure valves lead to a common main channel . The pressure and suction valves are mounted on the housing in a way, at least partially caulked and sealed by o-rings with respect to the housing.
    As soon as the control pressure in the control chamber exceeds the set pressure limit by means of the spring element, the piston moves with the closing member and the switching valve opens. Then, the low pressure pump element is switched to circulation and only the flow rate supplied by the high pressure pump element is applied to the pressure outlet. In this case also the low pressure pressure valve is kept closed by the pressure applied to the pressure outlet, so that the circulation of the low pressure pump element has low losses.
    Therefore, with a two-stage pump of this type, a significantly higher hydraulic fluid flow rate can be achieved up to a certain maximum limit pressure that can be adjusted through the spring element. As soon as the set limit pressure is applied to the pressure outlet and is directed to the control chamber, the circulation valve opens and the low pressure pump element is switched with low circulation losses, as described above. . This is particularly useful when a high flow rate is needed, for example to travel the run without load of a hydraulic system tool. The tool can be, for example, a hydraulically operated hand tool for pressing cable terminals or a hydraulically operated shoulder.
    A disadvantage of the known double stage pumps is that the maximum limit pressure is at most about 100 to 140 bar, respectively due to the spring element or the elastic force to be overcome to open the switching valve. A spring element that only allows the switching valve to be opened at higher limit pressures cannot be used regularly with the known switching valves. However, in some applications it is desirable to provide a high flow rate through both pump elements at the pressure outlet also at a pressure greater than. In addition, known double stage pumps are expensive to manufacture and therefore expensive.
    Summary of the invention
    Therefore, it is an object of the present invention to show a two stage pump that allows a higher limit pressure. This object is solved by the two stage pump according to claim 1. Furthermore, it is an object of the present invention to show a two stage pump that is cheaper to manufacture. This object is solved by the two stage pump according to claim 1 and claim 13. Suitable developments are described in the dependent claims.
    The two-stage pump for a hydraulic system according to the invention is distinguished in particular from the double-stage pumps already known by the fact that the switching valve comprises a push-valve that is mobile with respect to the housing and configured to move the piston and disposed between the control pressure chamber and the piston, where the pusher-valve has an effective diameter smaller than that of the piston. That is, to open the switching valve, the control pressure in the control pressure chamber is not applied directly to the piston, but indirectly through the push-valve that can be moved relative to the housing. Due to the smaller effective diameter of the push-valve, the piston can move with reduced forces. This means that upper limit pressures greater than 140 bar are generally enabled for the use of a spring element with the highest elastic constant possible despite the reduced space requirement. Therefore, spring elements with a lower elastic constant can be used, so that an opening of the switching valve can also occur only at higher pressures that are in particular greater than 100 to 140 bar. This also allows the spring element to have a simpler structure and, therefore, be cheap. During the closing movement of the piston, the push-valve moves in turn towards the control pressure chamber. Suitably, the ratio of the effective diameter of the push-valve to the effective diameter is in a range of 0.1 to 0.85, and particularly preferred in a range of 0.2 to 0.5.
    It is an advantage when the switching valve comprises a sleeve that is fixedly or at least partially fixed in the housing respectively, where the sleeve comprises the control pressure chamber and the valve thrust is movably arranged in the cuff In particular, it is advantageous when the sleeve is pressed flush in the housing. The connected control pressure is applied to the pusher-valve in the pressure control chamber of the sleeve, so that it moves relative to the sleeve and, therefore, to the housing towards the piston. Furthermore, by means of this arrangement, only the force of the valve thrust is caused to act on the sleeve, so that only a small force has to be transferred to the housing. This arrangement is cheap to manufacture and allows easy assembly.
    In this regard, it is advantageous when a return line pressure chamber is arranged between the sleeve and the piston, the valve thrust being able to move from the control pressure chamber to the return line pressure chamber by means of the pressure of control to open the switching valve. In the return line pressure chamber the return line pressure is applied, so that the closing movement of the piston is damped. Therefore, wear on the closing member and on the valve seat can be reduced. Here, it is useful when the piston comprises at least one outlet opening to the return line pressure chamber, where the outlet opening particularly represents a hydraulic resistance. Thus, during the closing movement of the piston a pressure is generated in the return line pressure chamber, so that the damping of the closing movement of the piston can be adjusted specifically by the number of outlet openings.
    Preferably, the thrust-valve comprises an axial end that contacts a piston mounting hole to move the piston, where the axial end is a rounded or spherical end, respectively. Alternatively, it may be suitable when the push-valve consists of a
    push-valve pin and a push-valve ball. The push-valve ball is arranged in the piston mounting hole and the push-valve pin comprises an axial end that makes contact with the push-valve ball move the piston. In particular, the mounting hole is formed as a tapered or tapered hole. This has the advantage that lateral forces are reduced due to the round contact surface between the rounded end of the push-valve of the push-ball and the mounting hole. Therefore, friction forces are reduced, which in total results in a lower switching hysteresis. When using a thrust ball, the axial end
    10 of the push-valve pin can be formed flat, so that this results in a cost advantage compared to a one-piece push-valve with a rounded end.
    Preferably, the piston comprises a spring chamber, where the element
    Spring 15 is at least partially arranged in the spring chamber. This allows a compact design of the switching valve and a very good centering of the spring element with respect to the piston.
    Preferably, the switching valve comprises a spring bushing.
    20 which has a spring support and can be screwed into the housing, where the spring element is disposed between the spring support and the piston. By screwing the spring bushing, the spring element can be replaced, for example, to insert a spring element with another elastic constant to adjust another limit pressure.
    25 In this regard, it is useful when the spring bushing comprises a female thread, in which the spring support is screwed into the female thread of the spring bushing. Therefore, the spring support is relatively mobile in the spring bushing by screwing and unscrewing, so that the deflection
    The desired spring element 30 is easy to adjust by a displacement of the spring support.
    Preferably, the spring support comprises a tool socket cavity. The tool socket cavity can be, for example, a groove with a hole or also a hexagonal socket, so that the deflection of the spring element can be adjusted quickly and easily. It is particularly advantageous when a fixing element presses on the tool socket. The fixing element can be, for example, a metal ball. After having adjusted and checked the deviation of the desired spring, the fixing element presses into the tool socket cavity, so that an incorrect adjustment of the support is excluded
    10 spring and therefore the adjusted deviation of the spring element. In this way, a particularly high operational reliability and an exact opening of the switching valve at the desired limit pressure is enabled.
    Preferably, the spring bushing comprises at least one connection of
    15 fluid with the tank. By opening the switching valve, the hydraulic fluid of the low pressure pump element that circulates through an inlet can be removed by said spring bushing.
    Preferably, the valve seat for the piston closure member
    20 is arranged in the housing. Therefore, a bushing or the like is not necessary to provide the valve seat for the piston closure element. Therefore, the two-stage pump is generally made cheaper and easier to assemble.
    Preferably, the two stage pump comprises a high pressure pressure valve assigned to the high pressure pump element and a high pressure suction valve assigned to the high pressure pump element, and said two stage pump comprising a valve Low pressure pressure assigned to the low pressure pump element and a suction valve
    30 low pressure assigned to the low pressure pump element. The high pressure pressure valve and / or the high pressure suction valve and / or the low pressure pressure valve and / or the low pressure suction valve are suitably screwed into the housing, where a respective cutting lip of the corresponding valve hermetically impinges or clears the housing.
    In addition, the problem is also solved by the fact that the two stage pump comprises a high pressure pressure valve assigned to the high pressure pump element and a high pressure suction valve assigned to the high pressure pump element, and that said two stage pump comprises a low pressure pressure valve assigned to the low pressure pump element and a low pressure suction valve assigned to the low pressure pump element. The two-stage pump according to the invention is distinguished from the two-stage pumps known from the prior art by the fact that the high pressure pressure valve and / or the high pressure suction valve and / or the pressure valve Low pressure and / or low pressure suction valve are screwed into the housing, where a respective cutting lip of the corresponding valve hermetically impinges or clears the housing.
    With this arrangement, sealing of the corresponding valves with respect to the quick and uncomplicated housing can be achieved. In addition, this also facilitates the assembly of the double stage pump, since the corresponding valves are screwed into the housing with the required torque, where at the same time the incision sealing of the cutting lip is generated. In addition, the cutting lip needs a significantly smaller installation space than conventional sealing elements. In addition, the cutting lip results in a smaller but well defined sealing diameter compared to conventional sealing elements, for example in comparison to a sealing ring made of soft iron.
    Preferably, the two-stage pump in addition to the cutting lip incision in the housing does not comprise any other additional sealing element to seal the corresponding valve or valves with respect to the housing. Thus, the sealing of the valves with respect to the housing is only established by cutting the cutting lip, so that additional or similar o-rings are not required. On the one hand, this saves costs of additional sealing elements. On the other hand, manufacturing is simplified, since similar grooves or structures must not be provided to receive the sealing element in the housing or in the corresponding valve.
    5 Preferably, the high pressure pressure valve and / or the low pressure pressure valve comprise a closing member, wherein the housing comprises the pressure valve seat or corresponding pressure valve seats. Therefore, a bushing or the like is not necessary to provide the pressure valve seat for a pressure valve closure element. For the
    10 Therefore, the two-stage pump is generally cost-effective. It is particularly advantageous when the high pressure pressure valve and / or the low pressure pressure valve have a ball as a closing member.
    Brief description of the drawings
    In the following, the invention is explained in detail with the help of the examples shown in the drawings. Here:
    Figure 1 schematically shows a two stage pump according to the invention in the form of a hydraulic diagram.
    Figure 2 schematically shows a plan view of the two stage pump according to the invention.
    Figure 3A schematically shows a cross-section of the two-stage pump according to a first example along the cutting line A-A shown in Figure 2, with the switching valve in the closed position.
    Figure 3B schematically shows a cross section of the pump
    Two stages according to the first example along the cutting line A-A shown in Figure 2, with the switching valve in the open position.
    Figure 4 schematically shows a cross-section of the two-stage pump according to the first example along the line B-B shown in Figure 2, with the switching valve in the open position.
    Figure 5 schematically shows an enlarged view of the point section according to Figure 4.
    Figures 6 to 9 schematically show several views of the two stage pump according to the invention.
    Figure 10 schematically shows a section along the cutting line CC shown in Figure 9. Figure 11A schematically shows a cross section of the two-stage pump according to a second example along the cutting line AA shown in Figure 2, with the switching valve in a closed position.
    Figure 11B schematically shows a cross-section of the two-stage pump according to the second example along the cutting line A-A shown in Figure 2, with the switching valve in an open position.
    Figure 12 schematically shows a plan view of the two stage pump according to the invention according to a third example.
    Figure 13 schematically shows a section along the D-D cutting line shown in Figure 12, with the switching valve in a closed position.
    Figure 14 schematically shows a section along the cutting line E-E shown in Figure 12, with the switching valve in an open position and
    Figure 15 schematically shows an enlarged detailed view of detail X according to Figure 14.
    Detailed description of the preferred embodiments of the invention
    In Fig. 1, a hydraulic diagram of the two-stage pump 1, 100, 200 according to the invention is illustrated, which is explained first below. The two stage pump 1, 100, 200 has a housing configured in the form of a block 2, 202 in which a high pressure pump element 3 and a low pressure pump element 4 are arranged, wherein the pump element High pressure 3 provides a lower hydraulic fluid flow rate than that of the low pressure pump element 4. The high pressure pump element 3 and the low pressure pump element 4 transport the hydraulic fluid through a flow channel common housing 41, 241 to a common pressure outlet 5. In addition, the two stage pump 1, 100, 200 comprises a tank connection
    7. The two stage pump 1, 100, 200 is connected to a hydraulic system (not shown), where the pressure outlet 5 forms the connection P of the hydraulic system and the tank connection 7 being connected to the tank T of the hydraulic system.
    The high pressure pump element 3 comprises a high pressure pressure valve 23, 223, a high pressure suction valve 24 and a piston 32 that can be moved in a supply chamber 36. The low pressure pump element 4 is correspondingly structured and comprises a low pressure pressure valve 25, 225, a low pressure suction valve 26, and a piston 33 that can be moved in a supply chamber 37. Pump elements 3, 4 will be described. in more detail below.
    In the housing 2, 202 of the two-stage pump 1, 100, 200, a switching valve 6 is also provided which is configured as a seat valve and connected to the supply chamber 37 of the low pressure pump element 4 through of a branch 42. In addition, a control pressure line 43, 243 is derived from the common housing channel 41, 241 downstream of the pressure valves 23, 25, 223, 225, so that the switching valve 6 It can be loaded with the pressure applied to the pressure outlet 5 as a control pressure through the control pressure line 43, 243. As soon as the control pressure exceeds the force of the spring element 8 acting as a compression spring - and therefore a limit pressure adjusted by the spring element 8 - the switching valve 6 is controlled to open open to the tank T. As illustrated, a hydraulic resistor can be arranged in the control pressure line 43, 24344, for example a hole.
    When the two stage pump 1, 100, 200 begins to operate, both pistons 32, 33 perform a suction movement. Here, the hydraulic fluid is drawn from the tank T to the supply chambers 36, 37 through the suction valves 24, 26. During the return movement of the pistons 32, 33 the hydraulic fluid present in the supply chambers 36, 37 is compressed and transported to the common housing channel 41, 241 and additionally to the pressure outlet 5 through the pressure valves 23, 25, 223, 225. Here, the lowest flow rate of the high pump element pressure 3 and the highest flow rate of the low pressure pump element 4 are added, where the switching valve 6 is in the closed position. The pressure applied to the pressure outlet 5 is applied through the control pressure line 43, 243 to the switching valve 6 which opens when the set pressure limit is reached or exceeded through the spring element 8, respectively. The low pressure pressure valve 25 remains closed after the limit pressure has been reached due to the high pressure in the common housing channel 41, 241, so that the flow rate of the low pressure pump element 4 is directed to the tank T through the bypass 42 and the open switching valve 6 with low losses. Therefore, the low pressure pump element 4 is switched to continuous operation with low losses.
    In Figures 3A, 3B and 4, sections of a first embodiment of the two-stage pump 1 are shown along the lines AA illustrated in Figure 2 (Figure 3A and Figure 3B) and BB (Figure 4) with the aid of which the switching valve 6 is explained in greater detail. Here, Figure 3A shows the switching valve 6 in a closed position and Figure 3B shows the switching valve 6 in an open position. The switching valve 6 comprises the spring element 8, a piston 9 that can be moved relative to the housing 2, and a closing member 10 disposed in the piston 9. The closing member 10 in this example is integrally formed with the piston 9 as a surrounding conical neck. As illustrated in Figure 3A, the closing member 10 in the closed position is attached to a valve seat 12 that is directly arranged in the housing 2. In the closed position of the closing member 10 illustrated in Figure 3A it cannot circulate hydraulic fluid to tank T through branch 42.
    In this example, the spring element 8 is a helical spring that is housed in a spring chamber 16 of the piston 9 and on one side rests against the front of the spring chamber 16 and on the other side against a support of spring 18. Here, the spring support 18 is formed as an endless screw with an axially projecting central neck for centering of the spring element 8. The spring support 18 is screwed into a female thread 19 of a spring bushing 17, wherein the spring bushing 17 is threaded into a respective hole of the housing 2.
    In order to adjust the deflection of the spring element 8, the spring support 18 is screwed or unscrewed from the spring bushing 17. For this, the spring support 18 comprises a plug or tool receiving cavity 20, for example a groove with a hole or a hexagonal cavity. When the spring support 18 is additionally screwed into the spring bushing 17 towards the piston 9, the spring element 8 is compressed, so that the deflection is increased. In order to avoid an unwanted erroneous adjustment of the adjusted deviation of the spring element 8, a fixing element 21 is inserted in the tool plug cavity 20. In this example, the fixing element 21 is a ball that is pressed into the tool socket cavity 20.
    As illustrated in Figure 2 and Figure 4, the spring bushing 17 comprises several fluid connections 22 through which the hydraulic fluid can circulate from the branch 42 to the tank T when the switching valve 6 is opened. This state, in which the closing element 10 is lifted from the valve seat 12, is illustrated in Figure 3B. The hydraulic fluid circulates from the supply chamber 37 of the low pressure pump element 4 through the branch 42 towards the spring bushing 17. Here, the hydraulic fluid can pass through the spring bushing 17 to the tank T through from
    5 fluid connections 22.
    In addition, the switching valve 6 comprises a sleeve 14 that is pressed into the housing 2. As shown in Figures 3A, 3B and 4, the sleeve 14 is pushed into the bore of the housing 2 housing the valve commutation
    10 6. The control pressure line 43 which is provided in the housing 2 as an oblique hole leads to a groove radially surrounding the sleeve 14, where within the sleeve 14 a control pressure chamber 11 is formed which is connected to the groove. In this example, the control pressure chamber 11 is a hole that penetrates the sleeve 14 in a radial direction, so
    15 that axial forces do not occur. In addition, the switching valve 6 comprises a valve thrust 13 which is arranged axially with respect to the sleeve 14. In detail, the valve thrust 13 is arranged so that its first axial end is directed towards the piston 9, where its second end axial leads to the control pressure chamber 11. The push-valve 13 closes
    20 hermetically by a sealing arrangement 49.
    The piston 9 comprises a conical mounting hole in which the second axial end of the valve thrust 13 is housed.
    25 As illustrated in Figure 3A, the piston 9 is not in contact with the sleeve
    14. Rather, a return line pressure chamber 15 is provided between the piston 9 and the sleeve 14 through which the pusher-valve 13 extends. By means of the sealing arrangement 49, fluid leaks are prevented from flowing between the control pressure chamber 11 and the pressure chamber of the line
    30 return 15. The piston 9 correspondingly comprises outlet openings 45 connecting the spring chamber 16 to the pressure chamber of the return line 15. As exemplified in Figure 3A, the effective diameter D1 of the valve thrust 13 is smaller than the effective diameter D2 of the piston 9. In this example, the effective diameter D1 is approximately 0.25 x D2.
    When the two stage pump 1 starts to work, it will immediately
    5 applies a control pressure through the control pressure line 43 and is directed to the control pressure chamber 11. Here, the valve thrust 13 is under pressure, so that it makes a small displacement in the direction axial until the first axial end of the valve thrust 13 is housed in the piston mounting hole 9. As illustrated, the first axial end of the
    10 pusher-valve 13 is configured rounded, so that the lateral forces between the pusher-valve 13 and the piston 9 are low. This results in low friction forces and, therefore, a low switching hysteresis. As soon as the control pressure in the control pressure chamber 11 has reached or exceeded, respectively, the set pressure limit through the
    15 spring element 8, the push-valve 13 axially moves the piston 9 towards the spring bushing 17 and thus compresses the spring element 8. Furthermore, during the axial movement of the piston 9, the closing member 10 is lifted from the seat of the valve 12 and the hydraulic fluid can circulate towards the tank T. Therefore, a control pressure is not applied directly to the piston 9 but
    20 indirectly through the push-valve 13.
    Due to the smaller effective diameter D1 of the thrust-valve 13 with respect to the effective diameter D2 of the piston 9, a smaller force is produced as a result for the displacement of the thrust-valve 13 and, therefore, of the piston
    25 9. Therefore, a spring element 8 with a lower elastic constant than with the known double stage pumps can be used to achieve the same limit pressures. In addition, spring elements with larger elastic constants that require less installation space can also be used, so that a limit pressure can be adjusted in general
    30 higher than 140 bar. In addition, significantly cheaper spring elements 8 can also be used.
    As soon as the control pressure in the control pressure chamber 11 decreases again below the set limit pressure, the spring element 8 moves the piston 9 towards the sleeve 14 until the closing member 10 rests on the seat Valve 12. Here, the hydraulic fluid in the return chamber 15 is forced by the piston 9 by the hydraulic fluid flowing through the outlet openings 45 to the spring chamber 16 during the closing movement of the piston 9 Thus, the closing movement of the piston 9 is generally damped, whereby the closing member 10 does not collide in the blow valve seat 12. Here, the piston 9 again displaces the
    10 pushes-valve 13 towards the control pressure chamber 11, since the control pressure in the control pressure chamber 11 has also fallen below the set limit pressure.
    Next, the pump elements 3, 4 are now described in detail with particular reference to Figures 4 and 8 to 10.
    As illustrated, the pistons 32, 33 extend laterally from the housing 2. The pistons 32, 33 of the pump elements 3, 4 can be driven, for example, through a common eccentric shaft (not shown). Of course,
    20 it is also conceivable that each of the two pistons 32, 33 is driven through a separate shaft. In addition, the pistons 32, 33 also do not have to be arranged in parallel and acting in the same direction, as shown.
    In this example, the pistons 32, 33, as illustrated in Figure 10, have the
    The same effective length has the piston 32 of the high pressure pump element 3 having a smaller diameter than the piston 33 of the low pressure pump element 4, so that a generally smaller flow rate at a higher pressure results. Both pump elements 3, 4 each have a coil-shaped spring assembly 34, 35 supported on one side in the
    30 housing 2 and on the other hand in a spring support 38, 39 which is arranged in the respective piston. 32, 33.
    When the double stage pump 1 starts operating, the pistons 32, 33 first perform a suction movement, that is, the pistons 32, 33 move in a direction away from the corresponding suction valves 24, 26 due to the force elastic spring assemblies 34, 35. Here, the
    5 hydraulic fluid is aspirated to the supply chambers 36, 37 through the suction valves 24, 26. Subsequently, the pistons 32, 33 perform a pressure movement, that is, the pistons 32, 33 move towards the valves suction 24, 26 Here, the hydraulic fluid is directed out of the supply chambers 36, 37 to the pressure valves 23, 25.
    10 The high pressure pressure valve 23 and the low pressure pressure valve 25 are constructed in the same manner and comprise spring loaded closing members 28, 29 in the form of balls. In the housing 2, the respective pressure valve seat 30, 31 is provided. By means of the hydraulic fluid
    15 leaving the supply chambers 36, 37, the closing members 28, 29 move against the force of the spring and the hydraulic fluid flows to the common housing channel 41 and as a result to the pressure outlet 5. In The pressure outlet 5 can be provided with a sealing element 40, for example an O-ring.
    20 Pressure valves 23, 25 are connected through a straight orifice that is closed with a plug 50 (see Figure 2) and together with an additional oblique hole as is evident from Figure 6 represents the common housing channel 41 .
    The high pressure suction valve 24 and the low pressure suction valve 26 are constructed in the same manner and each comprises a spring loaded slice 46, 47 as a closing member. In addition, the suction valves 24, 26 are threaded into a corresponding hole in the housing 2, so that the
    30 axial ends of the suction valves 24, 26 projecting in the housing lead to the respective supply chamber 36, 37.
    In addition, the high pressure pressure valve 23, the high pressure suction valve 24, the low pressure pressure valve 25 as well as the low pressure suction valve 26 each have a cutting lip 27 exemplified below. in detail with respect to the section of the low pressure pressure valve 25 illustrated in Figure 5, see also in the dotted circle of Figure 4.
    The cutting lip 27 is a structure that protrudes expressly in the circumferential direction of the valve 25 in the axial direction. By threading the valve 25 into the respective hole of the housing 2, the cutting lip 27 comes into contact with a sealing flange 48 of the housing 2. The cutting lip 27 plastically cuts the sealing flange 48 until the valve 25 has been tight with the required torque. Because the cutting lip 27 clears in the sealing flange 48 of the housing 2, the valve 25 is sealed with respect to the housing 2 so that no additional sealing elements between the valve 25 and the housing 2 are necessary.
    Next, a second embodiment of a two-stage pump 100 and a third embodiment of a two-stage pump 200 are explained in detail, in which due to the broad coincidences with the first example, only the corresponding differences are discussed. In addition, for reasons of clarity some reference symbols are not indicated in the figures. 11A to 15.
    In sections 11A and 11B two-stage pump sections 100 according to the invention are shown according to the second example according to the lines AA illustrated in figure 2. In figure 11A, the switching valve 6 is illustrated in the position closed while in Figure 11B, said switching valve 6 is illustrated in the open position.
    Next, the alternative design of a push-valve is explained in detail
    113. The push-valve 113 in this example consists of a push-valve pin 113a and a push-valve ball 113b. The first axial end of the push-valve pin 113a is formed flat with the push-ball ball 113b disposed in the piston mounting hole 9. This two-piece configuration of the push-valve 113, has the advantage that the pin valve thrust 113a with the first flat axial end and the valve thrust ball 113b represent suitable standard components. However, thanks to the ball of
    5 pushes-valve 113b, the lateral and frictional forces between the piston 9 and its mounting hole and the pusher-valve 113 are low, so that a low switching hysteresis is also possible. In addition, as the second axial end of the push-valve pin 113a is also shown, it can be configured flat.
    10 A third example of a two-stage pump 200 according to the invention is illustrated in Figures 12 to 15. While the valve pusher 13 with a first rounded axial end is illustrated in the figures, of course the valve pusher 113 can also be used in accordance with Figures 11A and 11B.
    15 The two-stage pump 200 according to this third example, on the one hand, differs by the design of the common housing channel 241 and the control pressure line 243 in the housing 202. In this example, as illustrated, these are formed as straight holes each of which is closed by closing caps (no
    20 shown) in the housing 202. Straight holes have manufacturing-oriented advantages compared to oblique holes.
    In addition, the two-stage pump 200 also differs by the pressure valves 223, 225. In section X illustrated in Figure 15 (see Figure 14), it is clear that the low pressure pressure valve 225 on the side of the closure member 29 comprises a partially surrounding collar 229. Said collar 229 is stamped / loaded in the radial direction 229, so that the closure member 29 is held in position. However, hydraulic fluid can flow freely, since collar 229 is formed only partially surrounding. Accordingly, the low pressure pressure valve 225 can be inserted as a pre-mounted unit into the respective orifice of the housing 202. The high pressure pressure valve 223 is formed identically, as is evident from
    from Fig. 14. Of course, such pressure valves can also be used in the first embodiment.
    List of reference symbols
    1, 100,
    200 Two stage pump
    2, 202 Case
    3 High pressure pump element
    4 Low pressure pump element
    5 Pressure outlet
    6 Switching valve
    7 Tank connection
    8 Spring element
    9 Piston
    10 Closing element
    eleven Pressure control chamber
    12 Valve seat
    13, 113 Push-valve
    14 Sleeve
    fifteen Line return pressure chamber
    16 Spring chamber
    17 Spring cap
    18 Spring support
    19 Female thread
    twenty Tool socket cavity
    twenty-one Fixing element
    22 Fluid connection
    23, 223 High pressure pressure valve
    24 High pressure suction valve
    25, 225 Low pressure pressure valve
    26 Low pressure suction valve
    27 Cutting lip
    High pressure valve closure element
    28 Pressure
    29 Low pressure valve closure element
    Pressure
    30 High pressure pressure valve seat
    31 Low pressure pressure valve seat
    32 High pressure pump element piston
    33 Low pressure pump element piston
    High pump element spring assembly
    3. 4 Pressure
    Low pump element spring assembly
    35 Pressure
    High pump element supply chamber
    36 Pressure
    Pump element supply chamber
    37 low pressure
    Spring support of high pump element
    38 Pressure
    Spring support of the low pump element
    39 Pressure
    40 Airtight element
    41, 241 Carcass channel
    42 Bypass to the switching valve
    Pressure control line to the valve
    43, 243 commutation
    44 Hydraulic resistor
    Four. Five Exit opening
    46 Slice of high pressure suction valve
    47 Slice of low pressure suction valve
    48 Watertight Flange
    49 Hermeticity Provision
    fifty Plug
    113a Push-Valve Pin
    113b Push ball-valve
    229 Necklace

    D1 Effective diameter of the push-valve D2 Effective diameter of the piston
    权利要求:
    Claims (12)
    [1]
    1. Two stage pump with switching valve (1, 100, 200) for a hydraulic system comprising a housing (2, 202), a pump element
    5 high pressure (3) and a low pressure pump element (4), a common pressure outlet (5) and a switching valve (6) that is disposed between a tank connection (7) and the element of low pressure pump (4) and configured as a seat valve, where the switching valve (6) is arranged in the housing (2) and comprises
    10 a spring element (8) and a piston (9) that can move relative to the housing (2, 202) against a force of the spring element (8), where the piston (9) comprises a closing member ( 10) which can be lifted from a valve seat (12) by means of a control pressure that is connected to the pressure outlet (5) and applied to a control pressure chamber (11) to
    15 that the switching valve (6) opens towards the tank (T), characterized in that the switching valve (6) comprises a push-valve (13) that is movable in relation to the housing (2) and configured to move the piston (9) and disposed between the control pressure chamber (11) and the piston (9), where the
    20 pusher-valve (13, 113) has a smaller effective diameter (D1) than that of the piston (9).
    [2]
    2. Two-stage pump (1, 100, 200) according to claim 1, characterized in that the switching valve (6) comprises a sleeve (14) disposed of
    25 fixed way in the housing (2, 202), where the sleeve (14) comprises the control pressure chamber (11) and the valve thrust (13, 113) being arranged mobilely in the sleeve (14).
    [3]
    3. Two stage pump (1, 100, 200) according to claim 2, characterized by
    30 that a return line pressure chamber (15) is disposed between the sleeve (14) and the piston (9), the valve thrust (13, 113) being able to move from the control pressure chamber (11) towards the pressure chamber of the return line (15) by means of the control pressure to open the switching valve (6).
    [4]
    4. Two stage pump (1, 200) according to any of the
    The preceding claims, characterized in that the valve thrust (13) comprises an axial end that makes contact with a piston mounting hole (9) for moving the piston (9), wherein said axial end is a rounded end.
    A two-stage pump (100) according to any one of the preceding claims 1 to 3, characterized in that the push-valve (113) comprises a push-valve pin (113a) and a push-valve ball ( 113b), where the push-valve ball (113b) is housed in a piston mounting hole (9) and where the push-valve pin (113a) comprises an end that makes
    15 contact with the thrust-valve ball (113b) to move the piston (9).
    [6]
    6. Two-stage pump (1, 100, 200) according to any of the preceding claims, characterized in that the piston (9) comprises a spring chamber (16), wherein the spring element (8) is willing to
    20 less partially in the spring chamber (16).
    [7]
    7. Two stage pump (1, 100, 200) according to any of the preceding claims, characterized in that the switching valve (6) comprises a spring bushing (17) having a spring support (18) and
    25 can be screwed into the housing (2, 202), where the spring element (8) is disposed between the spring support (18) and the piston (9).
    [8]
    8. Two-stage pump (1, 100, 200) according to claim 7, characterized in that the spring bushing (17) comprises a female thread (19), wherein the
    30 spring support (18) is threaded into said female thread (19) of the spring bushing (17).
    [9]
    9. Two-stage pump (1, 100, 200) according to claim 7 or 8, characterized in that the spring support (18) comprises a tool socket cavity (20), wherein a fixing element (21) it is pressed into said tool socket cavity (20).
    [10]
    10. Two-stage pump (1, 100, 200) according to any of the preceding claims 7 to 9, characterized in that the spring bushing (17) comprises at least one fluid connection (22) to the tank (T).
    10. Two-stage pump (1, 100, 200) according to any of the preceding claims, characterized in that the valve seat (12) for the closing member (10) of the piston (9) is arranged in the housing (2, 202).
    [12]
    12. Two stage pump (1, 100, 200) according to any of the
    The preceding claims, characterized in that said two-stage pump (1, 100, 200) comprises a high pressure pressure valve (23, 223) assigned to the high pressure pump element (3) and a high suction valve pressure (24) assigned to the pressure pump element (3), and because the two stage pump (1, 100, 200) comprises a valve
    20 low pressure (25, 225) assigned to the low pressure pump element (4) and a low pressure suction valve (26) assigned to the low pressure pump element (4), where the high pressure pressure valve (23, 223) and / or the high pressure suction valve (24) and / or the low pressure pressure valve (25, 225) and / or the valve
    25 low pressure suction (26) are threaded into the housing (2, 202), where a cutting lip (27) of the corresponding valve (23, 24, 25, 26, 223, 225) cleans in the housing tightly (2, 48, 202).
    [13]
    13. Two stage pump (1, 100, 200) with switching valve for a
    30 hydraulic system comprising a housing (2, 202), a high pressure pump element (3) and a low pressure pump element (4), a common pressure outlet (5) and a switching valve (6 ) which is arranged between a tank connection (7) and the low pressure pump element (4) and configured as a seat valve, where the switching valve (6) is arranged in the housing (2, 202) and it comprises a spring element (8) and a piston (9) that can be moved with
    5 with respect to the housing (2, 202) against a force of the spring element (8), where the piston (9) comprises a closing member (10) that can be lifted from a valve seat (12) by a pressure of control that is connected to the pressure outlet (5) and applied in a control pressure chamber (11), so that the switching valve (6) opens to the tank (T),
    10 comprising said two stage pump (1) a high pressure pressure valve (23, 223) assigned to the high pressure pump element (3) and a high pressure suction valve (24) assigned to the pressure pump element high pressure (3), and the two stage pump (1) comprising a low pressure pressure valve (25, 225) assigned to the low pressure pump element (4) and a
    15 low pressure suction valve (26) assigned to the pressure pump element (4), characterized in that the high pressure pressure valve (23, 223) and / or the high pressure suction valve (24) and / or the low pressure pressure valve (25, 225) and / or the valve
    20 low pressure suction (26) are threaded into the housing (2, 202), where a cutting lip (27) of the corresponding valve (23, 24, 25, 26, 223, 225) hermetically clears into the housing (2 , 48, 202).
    [14]
    14. Two stage pump (1, 100, 200) according to any of the
    25 preceding claims 12 or 13, characterized in that said two-stage pump (1) does not comprise any additional sealing element for sealing the corresponding valve (23, 24, 25, 26) with respect to the housing (2, 202) a part of the cutting lip (27) splitting into the housing (2, 48, 202).
    15. Two-stage pump (1, 100, 200) according to any of the preceding claims 12 to 14, characterized in that the high pressure pressure valve (23, 223) and / or the low pressure valve Pressure (25, 225) comprise a closing member (28, 29), wherein the housing (2, 202) comprises the corresponding pressure valve seats (30, 31).
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    同族专利:
    公开号 | 公开日
    US20180195510A1|2018-07-12|
    DE102017200212B4|2021-12-16|
    US10851909B2|2020-12-01|
    ES2685458B2|2020-09-14|
    DE102017200212A1|2018-07-12|
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    EP2634426A1|2012-03-02|2013-09-04|HAWE Hydraulik SE|Two-stage pump|
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    JP4111593B2|1998-07-07|2008-07-02|サンデン株式会社|Capacity control valve mechanism of variable capacity compressor|
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    法律状态:
    2018-10-09| BA2A| Patent application published|Ref document number: 2685458 Country of ref document: ES Kind code of ref document: A1 Effective date: 20181009 |
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    优先权:
    申请号 | 申请日 | 专利标题
    DE102017200212|2017-01-09|
    DE102017200212.3A|DE102017200212B4|2017-01-09|2017-01-09|Two-stage pump with switching valve|
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