• 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 invention relates to a method for measuring the differential pressure resistance of a fluid dynamic bearing system comprising at least one bearing gap (20, 32) filled with a bearing fluid having at least two openings (22, 34), the method comprising the steps of: connecting a first opening (34) of the A bearing gap (20) having a first active chamber (72), wherein a pressure (Pa) prevails in the first active chamber (72), connecting a second opening (22) of the bearing gap (20) to a second passive chamber (80), wherein a pressure (Pp) prevails in the second passive chamber (80), increasing and measuring the pressure (Pa) in the first active chamber (72), repeatedly measuring the pressure (Pp) in the second passive chamber (80) As soon as an increase in pressure (Pp) in the second passive chamber (80) is detected, a differential pressure (Pd) = (Pa) - (Pp) corresponding to a bearing resistance pressure (PL) is detected.
    公开号:AT519696A1
    申请号:T50188/2017
    申请日:2017-03-10
    公开日:2018-09-15
    发明作者:Löhr Markus；Vogtel Stefan
    申请人:Minebea Mitsumi Inc；
    IPC主号:
    专利说明:

    Method for testing the differential pressure resistance of a fluid dynamic bearing system
    The invention relates to methods for testing the differential pressure resistance of a fluid dynamic bearing system, as used for example for the rotary mounting of a spindle motor.
    Spindle motors with a fluid-dynamic bearing system are used, for example, for driving hard disk drives and fans and comprise a stationary motor component and a rotating motor component which are rotatably supported relative to one another by means of the fluid dynamic bearing system. The fluid dynamic bearing system has a bearing gap filled with a bearing fluid. Depending on the construction of the fluid dynamic bearing system, the bearing gap comprises a plurality of open ends, which are sealed, for example, by capillary sealing gaps, one end of the sealing gaps being connected directly or indirectly to the ambient atmosphere.
    DE 10 2012 020 866 A1 discloses spindle motors with various types of fluid dynamic bearings. FIGS. 1, 2 and 4 show fluid-dynamic bearings with fluid-dynamic radial bearings and axial bearings, while FIG. 3 shows a fluid-dynamic conical bearing. The fluid dynamic bearing systems shown here all have a bearing gap filled with a bearing fluid, which is sealed by at least one capillary sealing gap, wherein the sealing gap has an opening which is directly or indirectly connected to the ambient atmosphere.
    After the spindle motor has been fully assembled, it must be thoroughly cleaned to remove even the finest metal particles, other debris or other contaminants, such as oil or grease residues, that may be generated during assembly or abrasion of the engine components. The
    Among other things, cleaning is carried out by means of a gaseous, liquid or solid cleaning medium which acts on the spindle motor in the form of a cleaning jet. Suitable processes are, for example, compressed air blasting, dry ice blasting or CCV blasting, in which liquid carbon dioxide is used as blasting medium.
    When cleaning, it must be avoided that the cleaning medium acts on the storage system under too high pressure. Otherwise, there is a risk that too large pressure differences will form between the openings of the bearing gap or the openings of the capillary sealing gaps sealing the bearing gap, so that the bearing fluid is transported out of the bearing gap and the bearing becomes unusable.
    The so-called differential pressure resistance of a bearing system is a measure of the height of the pressure difference that may occur between certain openings of the bearing gap of a storage system at most.
    The greater the differential pressure resistance of the storage system, the greater the cleaning pressure and / or the exposure time of the cleaning medium can be selected, without this having detrimental effects on the storage system. During the cleaning process, the gaseous cleaning medium, for example compressed air or CO 2, also penetrate into the bearing gap and accumulate in the form of small gas bubbles in the bearing fluid. Gas inclusions in the bearing fluid can affect the bearing function and damage the bearing.
    To determine the differential pressure resistance of a fluid dynamic bearing system with a bearing gap having at least two openings, for example a device can be used which has a closed pressure chamber into which an opening of the bearing gap opens. The storage system is filled with bearing fluid. In this pressure chamber, the pressure is actively increased. In this case, the other opening of the bearing gap, which is located outside the pressure chamber, is visually observed and an increase / leakage / overflow of the bearing fluid or a movement of the surface meniscus of the bearing fluid, for example due to air bubbles that escape through the camp, as an evaluation criterion for the Differential pressure resistance (bearing resistance) used.
    Alternatively, the pressure drop in the chamber can be measured, e.g. B. when the pressure is generated with a water column. If the level of the water column drops, then air flows from the pressure chamber through the bearing gap, and the pressure in the pressure chamber decreases.
    The manual observation of the reaction of the bearing fluid succeeds only if the opening of the bearing gap is visually accessible. An automation of the recording and evaluation is hardly possible. The measurement of the pressure drop by means of a water column is also difficult to automate.
    Another way to measure the pressure applied to one of the openings of the bearing gap of the fluid dynamic bearing system in a conventional cleaning operation is the use of a pressure sensor which is inserted into the bearing gap or an opening of the bearing gap. In practice, the pressure sensor is not used directly in the camp, but connected via a tube or a hose with the gap opening. The bearing to be measured is built up without bearing fluid. Depending on the application, different bearing openings must be hermetically sealed, so that the pressure occurring in the bearing gap acts on the pressure sensor.
    So far, only one sensor has been used at a defined point of the bearing gap and the other bearing openings closed so that a certain pressure can be determined. In general, the sensor is mounted in a "blind hole", in which then the occurring during the application of the cleaning medium maximum pressure is measured, which would also act on the filled in the engine bearing fluid.
    It is the object of the invention to provide methods for testing and determining the differential pressure resistance of a fluid dynamic bearing, which operate simply and reliably.
    This object is achieved by methods having the features of the independent claims.
    Preferred embodiments and further advantageous features of the invention are the subject of the dependent claims.
    It has been found that in the first place the outflow velocity of the cleaning medium and thus the static and dynamic pressure acting on the spindle motor as well as the application or contact time (t) of this pressure are decisive for how great the differential pressure at the fluid dynamic bearing is. If the differential pressure occurring is greater than the differential pressure resistance of the bearing system, bearing fluid can be forced out of the bearing gap of the fluid-dynamic bearing of the spindle motor and / or gaseous constituents of the cleaning medium can accumulate or dissolve in the bearing fluid.
    The mobility of the bearing fluid, d. H. its viscosity also plays a role in the differential pressure resistance of the bearing system. The thicker the bearing fluid is, d. H. the greater the viscosity, the lower the risk that bearing fluid escapes from the bearing gap or gaseous cleaning medium dissolves in the bearing fluid.
    According to a first preferred embodiment of the invention, the fluid-dynamic bearing to be tested is constructed completely and the bearing gap is filled with bearing fluid. The fluid dynamic bearing system can already be installed in a designated spindle motor. According to the invention, a first active, pressurizable chamber is used, which is connected to a first bearing opening of the bearing gap, and a second passive chamber, which is connected to a second bearing opening of the bearing gap. The first active chamber is subjected to a pressure (Pa) and the applied pressure is measured. The pressure (Pp) prevailing in the second passive chamber is continuously measured and it is determined from which differential pressure (Pd) the resistance of the fluid bearing has been overcome and air from the first active chamber pressurized by the pressure (Pa) passes through the bearing gap enters the second passive chamber. As soon as an increase in the pressure (Pp) is determined in the second passive chamber, the so-called bearing resistance pressure (PL) is reached and air flows through the bearing gap of the bearing.
    Ideally, the passive second chamber is closed airtight and preferably kept as small as possible in the volume. As air flows from the first active chamber through the bearing gap, an increase in pressure (Pp) in the passive chamber can be observed.
    However, an increase in the pressure (Pp) in the passive chamber due to the air flow through the bearing gap acts against the force applied by the active chamber pressure (Pa), so that at a certain differential pressure between the two chambers, the camp again "closes" and through the bearing gap no further air flows into the passive chamber. In this case, the fluid dynamic bearing acts as a pressure equalization valve. If the pressure (Pa) in the active chamber is increased again, the bearing opens again and air flows into the passive chamber, the pressure (Pp) in the passive chamber rises again until the counter-pressure is reached which corresponds to the actively applied pressure (Pp). Pa) minus the bearing resistance pressure (PL). Thus, regardless of the pressure (Pa) applied in the active chamber, the bearing resistance pressure (PL) can be obtained by calculating the differential pressure (Pd) = (PL) = (Pa) - (Pp). (Pa) = pressure in the active chamber = applied pressure (test pressure) (Pp) = pressure in the passive chamber (Pd) = differential pressure = (Pa) - (Pp) (PL) = bearing resistance pressure (= differential pressure (Pd), ab which air flows through the warehouse)
    For airtight passive chamber and static state: (PL) = (Pa) - (Pp)
    Because of the build-up back pressure (Pp) in the passive chamber, the bearing is protected directly against leakage of the bearing fluid at a correspondingly slow pressurization, since a differential pressure (Pd) builds up between the chambers, which just prevents leakage. The prerequisite for this is that, when the bearing resistance pressure (PL) is exceeded, air can flow through the bearing from the active chamber into the passive chamber.
    It is also an automatic shutdown of the pressurization of the active chamber possible when an increase of the pressure (Pp) is detected in the passive chamber.
    According to a variant of the first embodiment of the invention, it is possible to use a passive second chamber which allows air to escape or which is not completely sealed. It is possible to determine the bearing resistance pressure (PL) at which the air first flows through the bearing. This happens as soon as an increase in pressure (Pp) in the passive chamber is measured. Due to the leaks in the passive chamber, however, the above formula is no longer valid because the passive chamber is constantly losing pressure.
    In this variant can serve as a pressure application in the active chamber, a control valve which is connected to a compressed air source and constantly nachfördert air into the active chamber. This does not require that the active chamber is completely air-tight. This allows for easy production and a simple test process.
    If the active chamber is hermetically sealed, a flow sensor on the active side can be used instead of the passive chamber to measure the flow of air through the bearing. As an alternative to a flow sensor, the control behavior of the inlet valve of the active chamber could also be evaluated in order to detect an increase in the air flow.
    According to a second embodiment of the invention, the fluid dynamic bearing or the spindle motor is built up and the bearing gap is not filled with bearing fluid.
    It is proposed a method and a corresponding structure of a measuring instrument with at least two pressure sensors or a differential pressure sensor. The pressure sensors are preferably introduced at the openings of the bearing gap where, in the filled storage system, the two menisci of the bearing fluid would be in the bearing gap. The bearing gap (without bearing fluid) is hermetically sealed between the pressure sensors, z. B. glued.
    The storage system or the spindle motor is now subjected to a conventional cleaning procedure, as it is carried out in mass production. As a cleaning medium, a gaseous and / or liquid and / or solid cleaning medium can be used, which is applied under pressure with a corresponding impact velocity on the surfaces of the spindle motor. Here, known cleaning methods, such as compressed air blast method, dry ice blasting or C02 snow blasting, are preferred. It can both the pressure acting on the storage system pressure of the cleaning medium, d. H. its Ausströmgeschwindigkeit, as well as the cleaning time are controlled. Due to the pressure of the cleaning medium, different pressures occur at the different openings of the bearing (bearing gap), since the cleaning medium does not act uniformly on the bearing system from all sides. This results in a differential pressure between the openings of the bearing gap, through which bearing fluid can be forced out of the bearing gap. In order to prevent leakage of bearing fluid from the bearing gap, it is necessary to determine the maximum allowable differential pressure in order to adjust the pressure of the cleaning medium so that the maximum differential pressure and / or the permissible exposure time of the cleaning medium is not exceeded. During the cleaning procedure, the pressure applied to the pressure sensors is measured and the differential pressure between two pressures is formed.
    When using two absolute pressure sensors, the difference between the two measured values is formed in order to obtain the differential pressure. When using a differential pressure sensor to obtain directly the differential pressure between the openings of the bearing gap.
    As a result, one obtains the actual differential pressure between the respective openings of the bearing gap, which would also be present when cleaning a real motor, regardless of whether a static or dynamic pressure is applied.
    In spindle motors with more than two openings of the bearing gap or two separate fluid dynamic bearing systems one can accordingly use a plurality of pressure sensors or close the openings not provided with pressure sensors. In fluid dynamic bearing systems with two or more independent fluid bearings, one can use three or more pressure sensors to simultaneously measure the pressures occurring in the bearing system.
    The aim is to determine which pressure is allowed to act on a bearing before the bearing fluid escapes from the bearing gap due to a differential pressure between the bearing openings. For setting cleaning machines (CO2 cleaning, air blowers, vacuum devices, etc.), this method provides a good starting value for the permissible pressurization of the bearing of the spindle motor.
    Further features and advantages of the invention will become apparent from the drawings and the following description of the preferred embodiments.
    1 shows a section through a first preferred embodiment of an arrangement for testing the differential pressure resistance of a fluid-dynamic bearing system for rotational mounting of a spindle motor.
    2 shows a section through a second preferred embodiment of an arrangement for testing the differential pressure resistance of a fluid-dynamic bearing system for rotational mounting of a spindle motor.
    Fig. 1 shows a section through a first preferred embodiment of an arrangement for testing the differential pressure resistance of a fluid dynamic bearing system for pivotal mounting of a spindle motor. The fluid dynamic bearing system of the spindle motor here consists of two separate fluid dynamic conical bearings.
    The spindle motor comprises a base plate 10 as a supporting structure, in which a fixed shaft 12 is arranged, so that it protrudes largely over the surface of the base plate. The shaft 12, together with two bearing cones 14, 26, the fixed component of the storage system. The bearing cones 14, 26 are arranged at an axial distance on the shaft 12 and fixedly connected thereto. The bearing cones 14, 26 have facing each other at an angle to the axis of rotation 52 extending conical bearing surfaces.
    Associated with the first bearing cone 14 is a first bearing bush 16, which has a partially conical bearing bore and a conical bearing surface which is separated from the conical bearing surface of the first bearing cone 114 by a first bearing gap 20, which is usually filled with a bearing fluid. The conical bearing surfaces and the bearing gap 20 extend at an acute angle obliquely to the axis of rotation 52. The first bearing cone 14 comprises on its bearing surface distributed over the circumference a number of bearing grooves. The bearing grooves are inclined at an acute angle to the horizontal and formed, for example, as a herringbone pattern. The bearing grooves need not be arranged on the bearing surface of the Lagerkonus114, but can also be arranged on the conical bearing surfaces of the bearing bush 16.
    The first bearing gap 20 has two open ends which adjoin the end faces of the bearing bush 16 in each case. The first open end of the bearing gap 20 is sealed by a capillary sealing gap 22 bounded by an outer peripheral surface of the first bearing cone 14 and an inner peripheral surface of the first bearing bush 16. The sealing gap 22 forms with the bearing gap 20 an obtuse angle (> = 90 °) and with the axis of rotation 52 at an acute angle. The sealing gap 22 is partially filled with bearing fluid and acts as a fluid reservoir and compensating volume. Preferably, both the sealing gap delimiting surfaces of the bearing bush and the bearing cone "inclined in the course of the bearing gap to the bearing outer by a small angle of between 0.5 degrees and 20 degrees in the direction of the axis of rotation, wherein the inclination angle of the inner peripheral surface of the first bearing bush 16 by a few Angle degrees is smaller than the inclination angle of the outer peripheral surface of the first bearing cone 14th
    The lower end of the first bearing gap 20 is sealed by a further sealing gap 24, along which preferably a dynamic pumping seal and a conical capillary seal are arranged. The dynamic pumping seal comprises pumping groove structures which are applied either on the shaft 12 or on the bearing bush 16 along the sealing gap 24, the pumping groove structures, upon rotation of the bearing bush 12, producing a pumping action on the bearing fluid in the sealing gap 24 in the direction of the bearing gap 20. In the storage cone 14 recirculation channels 25 are preferably arranged, through which a circulation of the bearing fluid within the conical bearing is possible.
    The second bearing cone 26 has conical bearing surfaces with bearing grooves, which form an acute angle with the axis of rotation 52. The bearing cone 26 is arranged in a second bearing bush 28, which also has conical bearing surfaces which are separated from the conical bearing surfaces of the second bearing cone 26 by a second bearing gap 32 which is usually filled with bearing fluid. The open ends of the second bearing gap 32 are each formed by a sealing gap 34 in the form of a conical capillary seal, as well as a
    Seal gap 36 sealed with pump seal and an additional conical capillary seal. The sealing gap 34 is bounded by an outer peripheral surface of the second Lagererkonus1 28 and an inner peripheral surface of the second bearing bushing 28. The sealing gap 34 forms with the bearing gap 32 at an obtuse angle (> = 90 °) and with the axis of rotation 52 at an acute angle.
    The two bearing bushes 16 and 28 of the oppositely acting conical bearing adjacent to each other and are separated by a spacer 38 from each other, which also serves to compensate for the temperature expansion of the bearing bushes 16, 28. The remaining space 42 between the outer periphery of the shaft 12 and the two bearing bushes 16, 28 and the spacer 38 is vented to produce a pressure equalization to the environment. For this purpose, the shaft 12 may have corresponding bores 48, 48a, which connects the intermediate space 42 with the outside atmosphere. As an alternative to the embodiment shown, a further bore 48b for ventilation can also open into a gap 46 between the base plate 10 and the lower conical bearing. In the bearing cone 26 recirculation channels 37 are preferably arranged, through which a circulation of the bearing fluid in the conical bearing is possible.
    The two sealing gaps 22, 34 form the outer boundary of the bearing fluid-filled part of the bearing. So that no impurities can penetrate into the sealing gaps 22 and 34 and escapes in particular only the smallest possible amount of the bearing fluid evaporating from the surface of the sealing gaps from the bearing, the two individual conical bearings beyond the sealing gaps 22, 34 each by a cover 18, 30th covered. The covers 18, 30 are, for example, stampings in the form of a profiled sheet metal ring, which has an outer edge, which is plugged or pressed onto an edge of the two bearing bushes 16, 28 and possibly additionally glued there. Each of the two covers 18, 30 extends radially inwardly in the direction of the shaft 12 and forms on the shaft 12 a bent leg, which forms a narrow air gap 50 together with the surface of the shaft 12.
    The two bearing bushes 16 and 28 are held in a central recess of a hub 40 of the spindle motor, for example by a press connection, and / or are glued into the hub 40. Here, the adhesive can serve as a lubricant for the press connection and ensure better sealing of the bearing. Both bearing bushes 16 and 28 preferably have a collar on the outer circumference, which rests on an end face of the edge of the opening of the hub 40. Preferably, the bearing bushes 16, 28 made of steel, ceramic or the like, in particular made of a material with a small coefficient of thermal expansion, while the hub 40, for example, made of aluminum, so a material with a comparatively large coefficient of thermal expansion, and for receiving storage disks serves, which also consist of aluminum.
    Alternatively, the two bearing bushes can be made in one piece from steel, in particular when the hub carries storage disks made of glass and therefore also made of steel and is preferably designed in one piece with the bearing bushes. The bearing cones 14, 26 are arranged relative to the bearing bushes 16, 28 so that the bearing gaps 20, 32 have a defined width of a few micrometers at room temperature. The bearing capacity of the conical bearings depends inter alia on the width of the bearing gaps 20, 32 and the viscosity of the bearing fluid contained therein.
    The spindle motor is driven by an electromagnetic drive system consisting of a stator assembly (not shown) attached to the base plate 10 and a rotor magnet 45 mounted on the hub 40 opposite the stator assembly and radially surrounded by a ferromagnetic yoke 44.
    To test the differential pressure resistance of the bearing system, the bearing system is constructed, wherein the bearing gaps 20, 32 are not filled with bearing fluid.
    Radial accesses in the form of access holes 60a, 60b, 60c are created from the outside. A first access bore 60a is provided radially from the outside to an annular gap 54 at the lower end of the outer sealing gap 22 of the first conical bearing. In the annular gap 54 open the recirculation channels 25 of the first bearing cone '14th
    A second access hole 60b is provided radially from the outside to the space 42 between the two conical bearings. As a second access and the holes 48 and 48 a can be used in the shaft 12, which open directly into the gap 42.
    A third access hole 60c is provided radially from the outside to an annular gap 56 at the lower end of the outer sealing gap 34 of the second conical bearing.
    Into these access bores 60a, 60b, 60c, tubes 62a, 62b, 62c or tubes of suitable diameter are inserted. Each tube 62a, 62b, 62c is connected to a corresponding pressure sensor 64a, 64b, 64c.
    The air-conducting connections between the respective accesses 60a, 60b, 60c, which run within the storage system, are closed. For this example, adhesive is used, which is introduced between the shaft 12 and the bearing bushes 16, 28 in the transition region between the bearing gaps 20, 32 and the adjacent inner sealing gaps 24, 36 and closes the bearing gaps between the pressure sensors. Thus, the pressure sensors 64a, 64b, 64c only measure the pressures applied to the associated openings of the storage system. The first pressure sensor 64a measures the pressure applied to the outer sealing gap 22 of the upper bearing.
    The second pressure sensor 64b measures the pressure which prevails in the intermediate space 42 between the bearings, the inner sealing gaps 24, 36 and the bores 48 of the shaft 12. The third pressure sensor 64c measures the pressure applied to the outer sealing gap 34 of the lower bearing.
    The spindle motor with the correspondingly prepared storage system is now subjected to a conventional cleaning process, as it is carried out during the manufacture of the spindle motor. The cleaning process may be, for example, a cleaning by means of compressed air or CCV snow or something similar, in which pressurized cleaning jet 66 of a cleaning medium acts on the spindle motor for a certain exposure time.
    The cleaning jet 66 hits from one side, for example the top, with high pressure on the spindle motor and the storage system and flows around the spindle motor. This raises at the openings of the storage system, d. H. the sealing gap 22, the sealing gap 34 and the bore 48 of the shaft 12, different pressures, which are detected by the pressure sensors 64a, 64b, 64c.
    The differential pressure (Pdi) at the bearing gap 20 between the openings of the sealing gaps 22 and 24 results from the difference between the pressures measured by the pressure sensors 64a and 64b.
    The differential pressure (Pd2) at the bearing gap 32 between the openings of the sealing gaps 34 and 36 results from the difference between the pressures measured by the pressure sensors 64b and 64c.
    2 shows a section through a second preferred embodiment of an arrangement for testing the differential pressure resistance of a fluid-dynamic bearing system for rotational mounting of a spindle motor. The fluid dynamic bearing system of the spindle motor consists of two separate fluid dynamic conical bearings. The fluid-dynamic bearing system differs somewhat from the fluid-dynamic bearing system of FIG. 1. The same components and components with the same functions are designated by the same reference numerals as in the bearing system of FIG. 1.
    In contrast to FIG. 1, the bearing system of FIG. 2 has a one-piece bearing bush 17, which surrounds both bearing cones 14, 26 of the two fluid-dynamic conical bearings. The space 42 between the two conical bearings is formed by an annular relief groove on the inner peripheral surface of the bearing bush 17. The undercut can also be provided on the shaft 12. The two bearing gaps 20, 32 of the conical bearing and sections of the capillary sealing gaps 22, 24 and 34, 36 are filled with bearing fluid.
    The bearing bush 17 is received in a hub 40 of the spindle motor.
    The device for testing the differential pressure resistance of the bearing system preferably comprises a lower part 70, on which the lower edge of the hub 40 preferably rests sealingly. The lower part 70 has a first active chamber 72, the opening of which faces the storage system. In this first active chamber 72 open the openings of the outer sealing gap 34 of the lower bearing and the bores 48, 48 a, 48 b of the shaft 12, which are connected to the openings of the inner sealing gaps 24, 36.
    Furthermore, the device comprises an upper part 78, which preferably rests sealingly on the upper edge of the hub 40. The upper part 78 has a second passive chamber 80, the opening of which faces the storage system. In this second passive chamber 80 opens the opening of the outer sealing gap 22 of the upper bearing.
    The first active chamber 72 is connected via an access opening 74 to a compressed air source 76. Compressed air in this context generally means a gas which can be introduced under pressure into the first active chamber 72. The second passive chamber 80 also has an access port 82 connected to a pressure sensor 84.
    To measure the differential pressure resistance of the upper conical bearing of the storage system, only the pressure (Pa) in the first active chamber 72 is steadily increased from the ambient pressure. This pressure (Pa) is on the one hand at both sealing gaps 34, 36 of the lower bearing alike, which has no effect on the lower bearing and is not taken into account in this measurement. The pressure (Pa) is applied via the bores 48, 48a of the shaft 12 to the inner sealing gap 24 of the upper bearing.
    In the passive chamber there is a pressure (Pp), which also corresponds to the ambient pressure at the beginning of the measurement. This pressure (Pp) is applied to the outer sealing gap 22 of the upper bearing.
    The pressure (Pa) in the active chamber 72 is now increased until the pressure resistance of the fluid bearing is overcome, that is, the pressure difference (Pa) - (Pp) is so great that air from the active chamber 72 through the inside Seal gap 24, the bearing gap 20 and the outer sealing gap 22 of the upper bearing flows into the passive chamber 80. By the air flow, the pressure (Pp) in the passive chamber 80 slightly increases, which is detected by the pressure sensor 84.
    Now, the differential pressure (Pd) = (Pa) - (Pp) is formed, which corresponds to the desired bearing resistance pressure (PL), d. H. the pressure difference at which air flows through the upper bearing.
    In order to determine the differential pressure resistance of the lower bearing, the assembly consisting of the hub 40 and the bearing system is reversed and held between the lower part 70 and the upper part 78 of the device.
    List of Reference Numbers: 10 base plate 12 shaft 14 first bearing cone 14a bearing grooves 16 first bearing bush 17 bearing bushing one piece 18 cover 20 first bearing gap 22 sealing gap 24 sealing gap 24a pump seal 25 recirculation channel 26 second bearing cone 26a bearing grooves 28 second bearing bush 30 cover 32 second bearing gap 34 sealing gap 36 sealing gap 36a Pump seal 37 Recirculation channel 38 Spacer 40 Hub 42 Interspace 44 Yoke 45 Rotor magnet 46 Interspace 48 Bore 48a, b Bore 50 Air gap 52 Rotary axis 54 Annular gap 56 Annular gap 60a, b, c Access bore 62a, b, c Tubes 64a, b, c Pressure sensor 66 Purge jet 70 Lower part 72 first active chamber 74 access opening 76 compressed air source, pressure sensor 78 upper part 80 second passive chamber 82 access opening 84 pressure sensor
    权利要求:
    Claims (9)
    [1]
    claims
    A method of measuring differential pressure resistance of a fluid dynamic bearing system having at least one bearing gap (20, 32) filled with a bearing fluid having at least two openings (22, 34), comprising the steps of: connecting a first opening (34) of the bearing gap (20) a first active chamber (72), wherein in the first active chamber (72) there is a pressure (Pa), connecting a second opening (22) of the bearing gap (20) with a second passive chamber (80), wherein in the second passive Chamber (80) there is a pressure (Pp), increasing and measuring the pressure (Pa) in the first active chamber (72), repeatedly measuring the pressure (Pp) in the second passive chamber (80), and as soon as an increase in pressure (Pp) in the second passive chamber (80), a differential pressure (Pd) = (Pa) - (Pp) corresponding to a bearing resistance pressure (PL) is detected.
    [2]
    2. The method according to claim 1, characterized in that the first active chamber (72) and / or the second passive chamber (80) are hermetically sealed.
    [3]
    3. The method according to claim 1, characterized in that the first active chamber (72) and / or the second passive chamber (80) are not completely hermetically sealed.
    [4]
    4. The method according to claim 3, characterized in that an air flow through the bearing gap (20, 32) by means of a flow sensor on the side of the first active chamber (72) is detected.
    [5]
    5. A method for measuring the differential pressure between at least two openings (22, 24 or 34, 36) at least one bearing gap (20, 32) of a fluid dynamic bearing system, wherein the bearing gap (20, 32) is free of bearing fluid and portions of the bearing gap (20 , 32) are hermetically sealed between the respective openings (22, 24 or 34, 36), the method comprising the steps of: a) applying a fluid medium in the form of a fluid jet (66) directed from a specific direction onto the fluid dynamic bearing system, wherein the fluid jet (66) acts on the fluid dynamic bearing system at a certain outflow speed (pressure) and for a certain contact time (t), b) measuring a pressure (Pdi) in the region of the first opening (22, 34) of the bearing gap (20, 32) of the fluid dynamic bearing system during the contact time (t), c) measuring a pressure (Pd2) in the region of the second opening (32, 36) of the bearing gap (32) of the fluid dynamic bearing system wä During the exposure time (t), d) forming the differential pressure (Pd) = (Pdi) - (Pd2) from the measured pressures (Pdi) and (Pd2).
    [6]
    6. The method according to claim 7, characterized in that the steps a) to d) are repeated several times with changed Ausströmgeschwindigkeiten and / or changed exposure times (t) of the fluid jet (66) of the fluid medium.
    [7]
    7. The method according to any one of claims 7 or 8, characterized in that a pressure diagram from the obtained measured values of the differential pressure (Pd) in dependence on outflow velocity and / or reaction time (t) is created.
    [8]
    8. Apparatus for measuring the differential pressure resistance of a fluid dynamic bearing system comprising at least one bearing gap (20, 32) filled with a bearing fluid having at least two openings (22, 34), comprising: a first active chamber (72) having a first opening ( 34) of the bearing gap (20), wherein in the first active chamber (72) there is a pressure (Pa), a second passive chamber (80) which is connected to a second opening (22) of the bearing gap (20), wherein in the second passive chamber (80) there is a pressure (Pp), means (76) for increasing and measuring the pressure (Pa) in the first active chamber (72), means (84) for measuring the pressure in the second passive chamber (80) and detecting an increase in pressure (Pp) in the second passive chamber (80), and means for detecting a differential pressure (Pd) = (Pa) - (Pp) corresponding to a bearing resistance pressure (PL) ,
    [9]
    9. A device for measuring the differential pressure between at least two openings (22, 24 or 34, 36) at least one bearing gap (20, 32) of a fluid dynamic bearing system, wherein the bearing gap (20, 32) is free of bearing fluid and portions of the bearing gap (20 , 32) are hermetically sealed between the respective openings (22, 24 or 34, 36), the apparatus comprising: means for applying a fluid medium in the form of a fluid jet (66) directed from a specific direction onto the fluid dynamic bearing system, the Fluid jet (66) with a certain Ausströmgeschwindigkeit (pressure) and for a certain exposure time (t) acts on the fluid dynamic bearing system, means (64a, 64b) for measuring a pressure (Pdi) in the region of the first opening (22, 34) of the bearing gap (20, 32) of the fluid dynamic bearing system during the contact time t, means for measuring (64c, 64b) a pressure (Pd2) in the region of the second opening (32, 36) of the bearing gap (20, 32 ) of the fluid dynamic bearing system during the action time t, means for forming the differential pressure (Pd) = (Pdi) - (Pd2) from the measured pressures (Pd1) and (Pd2).
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    同族专利:
    公开号 | 公开日
    AT519696B1|2018-12-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH0310139A|1989-06-08|1991-01-17|Mazda Motor Corp|Method for inspecting lubricating system of engine|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50188/2017A|AT519696B1|2017-03-10|2017-03-10|METHOD FOR MEASURING THE DIFFERENTIAL PRESSURE STRENGTH OF A FLUID DYNAMIC STORAGE SYSTEM|ATA50188/2017A| AT519696B1|2017-03-10|2017-03-10|METHOD FOR MEASURING THE DIFFERENTIAL PRESSURE STRENGTH OF A FLUID DYNAMIC STORAGE SYSTEM|
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