GB2303413A - Dynamic pressure bearing assembly - Google Patents
Dynamic pressure bearing assembly Download PDFInfo
- Publication number
- GB2303413A GB2303413A GB9614948A GB9614948A GB2303413A GB 2303413 A GB2303413 A GB 2303413A GB 9614948 A GB9614948 A GB 9614948A GB 9614948 A GB9614948 A GB 9614948A GB 2303413 A GB2303413 A GB 2303413A
- Authority
- GB
- United Kingdom
- Prior art keywords
- dynamic pressure
- sleeve
- pressure bearing
- shaft
- thrust plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/10—Construction relative to lubrication
- F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
- F16C33/106—Details of distribution or circulation inside the bearings, e.g. details of the bearing surfaces to affect flow or pressure of the liquid
- F16C33/107—Grooves for generating pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/02—Sliding-contact bearings for exclusively rotary movement for radial load only
- F16C17/026—Sliding-contact bearings for exclusively rotary movement for radial load only with helical grooves in the bearing surface to generate hydrodynamic pressure, e.g. herringbone grooves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/10—Sliding-contact bearings for exclusively rotary movement for both radial and axial load
- F16C17/102—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure
- F16C17/107—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure with at least one surface for radial load and at least one surface for axial load
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/2009—Turntables, hubs and motors for disk drives; Mounting of motors in the drive
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head
- G11B5/53—Disposition or mounting of heads on rotating support
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2370/00—Apparatus relating to physics, e.g. instruments
- F16C2370/12—Hard disk drives or the like
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
PROBLEM TO BE SOLVED: To ensure rotating accuracy in an axial direction by prevent slip-off in the axial direction at the time of high speed rotation, and also to prevent vibration and oscillation. SOLUTION: In a dynamic pressure, a shaft 3 is fixed on either one center part of a fixing member 2 and a rotating member 1, a sleeve 8 is fixed on the other center part, they are engaged with each other, and a dynamic pressure bearing is formed between the shaft 3 and the sleeve 8. A thrust plate 7 is fixed on the shaft 3, the thrust plate 7 is arranged on a circumferential recessed part 10 formed on the inner circumferential surface of the sleeve 8, and thereby, a thrust dynamic pressure bearing is formed between the upper/lower surfaces of the thrust plate 7 and the circumferential recessed part 10.
Description
DYNAMIC PRESSURE BEARING DEVICE
The invention relates to a dynamic pressure bearing device which is used for rotating at high speed a magnetic disk in a personal computer, a word processor, or the like, a rotary drum in a video tape recorder (VTR), and particularly to a dynamic pressure bearing device in which the accuracy during rotation in the axial direction can be ensured.
In an office automation (OA) business machine such as a personal computer or a word processor, or an audio visual AV machine such as a video tape recorder, a rotation driving apparatus for rotating at high speed a magnetic disk or a rotary drum is incorporated. In such a rotation driving apparatus, used is a dynamic pressure bearing device which utilizes a fluid such as a lubricant in order to ensure the accuracy during rotation at high speed and prevent noises and vibrations from occurring.
Fig. 4 is a longitudinal section view showing the structure of a prior art dynamic pressure bearing device. A stator 45 is disposed on the outer periphery of a cylindrical portion 43 which is disposed on a base 41a of a stationary member 41 so as to elongate in a direction upstanding from the base 41a (hereinafter, referred to as axial direction). A sleeve 46 is fixed to the inner periphery of the cylindrical portion 43. A shaft 42 fixed to the center portion of a rotary member 40 is fitted into the sleeve 46 with forming a small clearance therebetween.
A cylindrical portion 40a which elongates toward the base 41a of the stationary member 41 and in parallel with the cylindrical portion 43 is formed in the outer periphery of the rotary member 40. A rotor 44 configured by magnets is disposed on the inner face of the cylindrical portion 40a and at a position opposing the stator 45. As shown in the figure, on the outer periphery of the shaft 42 or the inner periphery of the sleeve 46, a plurality of dynamic pressure grooves 42a and 42b which elongate in the circumferential direction and have a herringbone-like shape or a spiral shape are formed in two portions separated from each other in the axial direction. In other words, the shaft 42 and the sleeve 46 form a dynamic pressure bearing.The lower face of the shaft 42 is supported by means of a pivot support formed by the shaft and a plate 47 fittingly attached to the cylindrical portion 43 of the stationary member 41, or by forming a thrust dynamic pressure bearing.
As shown in Fig. 5, the lower end face of the shaft 42 which is fixed to the center portion of the rotary member 40, on which the dynamic pressure grooves 42a and 42b are formed, and which is fitted into the sleeve 46 may be configured into a thrust bearing structure and provided with a lock ring 48 for preventing the shaft 42 from slipping off.
As shown in Fig. 4, in the dynamic pressure bearing device wherein the sleeve 46 is fittingly fixed to the cylindrical portion 43 of the stationary member 41 on which the stator 45 is disposed and the shaft 42 fixed to the rotary member 40 is fitted into the sleeve 46 so as to attain the rotating operation, the shaft 42 is held to the stationary member 41 by a magnetic force exerted between the rotor 44 and the stator 45. However, the holding due to the magnetic force is not sufficient for preventing the shaft 42 from slipping off from the sleeve 46 in the axial direction.
In the case where the lock ring 48 is attached as a countermeasure for prevention of slipping off as shown in
Fig. 5, the clearance t between the lock ring 48 and the lower end face of the sleeve 46 is large, and hence there arises a problem in that the accuracy in the axial direction cannot be ensured during rotation.
The invention has been conducted in view of the abovediscussed problem. It is an object of the invention to provide a dynamic pressure bearing device in which the shaft can be prevented from slipping off in the axial direction during rotation at high speed so that the accuracy in the axial direction in the axial direction is ensured, and swings, vibrations, etc. can be prevented from occurring.
In order to solve the above-discussed problem, it is an object of the invention to provide a dynamic pressure bearing device in which a shaft is fixed to one of stationary and rotary members, a sleeve is fixed to the other one of the stationary and rotary members, the shaft is fitted into the sleeve, and a dynamic pressure bearing is formed between the shaft and the sleeve, wherein a thrust plate is fixed to the shaft, the thrust plate is placed in an annular recess space formed in an inner periphery of the sleeve, and a thrust dynamic pressure bearing is formed between each of upper and lower faces of the thrust plate and the annular recess. Furthermore, a dynamic pressure bearing device wherein the thrust dynamic pressure bearings are formed by forming dynamic pressure grooves in the upper and lower faces of the thrust plate is provided.Moreover, a dynamic pressure bearing device wherein the thrust dynamic pressure bearings are formed by forming dynamic pressure grooves in upper and lower faces of the annular recess of the sleeve is provided.
In the case where a dynamic pressure bearing device has any one of the configurations described above, when the rotary member is rotated at high speed, a dynamic pressure bearing which is silent and free from vibrations is formed between the shaft and the sleeve by the pumping action of dynamic pressure grooves formed on the shaft or the inner periphery of the sleeve. Furthermore, a thrust dynamic pressure bearing is formed between the thrust plate and the annular recess of the sleeve by the pumping action of the dynamic pressure grooves formed on the upper and lower faces of the thrust plate or those of the annular recess of the sleeve. The shaft is prevented from slipping off, and the rotary member as a whole is prevented from vertically vibrating or swinging, whereby the accuracy in the axial direction can be ensured.
The invention will be further described by way of example with reference to the accompanying drawings, in which,
Fig. 1 is a longitudinal section view showing the structure of a dynamic pressure bearing device forming
an embodiment of the invention;
Fig. 2 is a plan view of a thrust plate which is fixed to a shaft of the dynamic pressure bearing device of
Figure 1;
Fig. 3(A) is a longitudinal section view showing the structure of a modification of the dynamic pressure bearing device of Figure 1 and Fig. 3(B) is a partial enlarged view of Fig. 3(A);
Fig. 4 is a longitudinal section view showing the structure of a prior art dynamic pressure bearing device; and
Fig. 5 is a longitudinal section view showing the structure of the main portion of another prior art dynamic pressure bearing device.
Hereinafter, specific embodiments of the invention will be described with reference to the accompanying drawings.
AS shown in Fig. 1, a cylindrical portion 4 is formed on a base 2a of a stationary member 2 so as to extend in a direction upstanding from the base 2a (hereinafter, referred to as axial direction). A sleeve 8 on which a peripheral step portion 8a is formed is fittingly attached to the upper portion of the inner periphery of the cylindrical portion 4.
The outer periphery side of the sleeve 8 has a two-step structure consisting of a small-diameter portion 8b and a large-diameter portion 8c. The small-diameter portion 8b of the sleeve 8 is fitted into the inner periphery of the cylindrical portion 4 in such a manner that the step face of the large-diameter portion 8c abuts against the front end face 4a of the cylindrical portion 4, thereby engaging the sleeve with the cylindrical portion. A stator 6 having coils through which a current is to flow is disposed on a portion outer than the front end face 4a of the cylindrical portion 4 into which the small-diameter portion 8b of the sleeve 8 is fitted and engaged, i.e., on the outer face of the large-diameter portion 8c of the sleeve 8.
A shaft 3 which fixed to the center portion of a rotary member 1 and on which dynamic pressure grooves 3a and 3b having a herringbone-like shape or a spiral shape are formed is fitted into the sleeve 8 with forming a small clearance therebetween. A plurality of the dynamic pressure grooves 3a and 3b extend in the circumferential direction and are formed in two portions separated from each other in the axial direction. A rotor 5 configured by magnets is disposed on the inner periphery of a cylindrical portion la of the rotary member 1 and at a position opposing the stator 6. The dynamic pressure grooves 3a and 3b may be formed in the inner face of the sleeve 8,instead.af on the shaft 3.
A thrust plate 7 is fixed to the shaft 3. Dynamic pressure grooves 7a which have a herringbone-like shape or a spiral shape as shown in Fig. 2 are formed in the upper and lower faces 11 and 12 of the thrust plate 7. The outer end portion of the thrust plate 7 is placed in an annular recess 10 which is defined by a step portion 8a formed in the upper portion of the sleeve 8, and the lower face 9a of a ring member 9 fitted into the upper internal end portion of the sleeve 8. The upper and lower faces 11 and 12 of the thrust plate 7 extend so as to be perpendicular to the axis of the shaft 3, and in parallel with the surface of the step portion 8a of the sleeve 8 and the lower face 9a of the ring member 9. The lower end of the shaft 3 is not subjected to thrust support but is in a free state.A fluid such as a lubricant is filled in a space between the sleeve 8 fitted into the cylindrical portion 4 formed on the stationary member 2, and the shaft 3 disposed on the rotary member 1, thereby forming a dynamic pressure bearing. The thrust plate 7 on the upper and lower faces of which the dynamic pressure grooves 7a are formed is placed in the annular recess 10 which is defined by the step portion 8a of the sleeve 8 and the lower face 9a of the ring member 9 constituting a part of the sleeve 8, and the lubricant is filled into the recess, thereby forming a thrust dynamic pressure bearing.
When the thrust plate 7 fixed to the shaft 3 is positioned at or in the vicinity of the center of gravity of the rotary member 1, swings and deflection can be further reduced.
The dynamic pressure bearing device of the invention has the configuration described above. When the rotary member 1 is rotated at high speed, a dynamic pressure bearing which is silent and free from vibrations is formed between the shaft 3 and the sleeve 8 by the pumping action of the dynamic pressure grooves 3a and 3b formed on the shaft 3. Furthermore, a thrust dynamic pressure bearing is formed between the thrust plate 7, and the step portion 8a of the sleeve 8 and the lower face of the ring member 9 by the pumping action of the dynamic pressure grooves 7a formed in the upper and lower faces of the thrust plate 7.
Therefore, the shaft 3 is prevented from slipping off, and the rotary member 1 as a whole including the shaft 3 is prevented from vertically vibrating or swinging, whereby the accuracy in the axial direction can be ensured.
In the embodiment shown in Fig. 1, the stator 6 is disposed in close proximity to or directly on the outer periphery of the sleeve 8, and hence the dynamic pressure bearing device can be made compact in a radial direction.
When the same size in a radial direction is to be employed, the stator 6 can be enlarged in radial direction so that the torque is increased.
Figs. 3(A) and 3(B) are longitudinal section views showing the structure of a modification of the dynamic pressure bearing device of the invention.
In the embodiment, a shaft 3 on which dynamic pressure grooves 3a and 3b having a herringbone-like shape or a spiral shape are formed is fixed in a standing manner to a base 2a of a stationary member 2. A sleeve 8 into which the shaft 3 is to be fitted with forming a small clearance therebetween is fixed to the center portion of a rotary member 1. A cylindrical portion 4 of a size which allows the sleeve 8 to loosely enter the cylindrical portion is formed in the axial direction so as to surround the shaft 3 fixed to the base 2a of the stationary member 2. A stator 6 having coils through which a current is to flow is disposed on the outer periphery of the cylindrical portion 4. A rotor 5 configured by magnets is disposed on the inner face of a cylindrical portion la formed in the outer side of the rotary member 1, and at a position opposing the stator 6.A thrust plate 7 is fixed to the shaft 3. Dynamic pressure grooves 7a are formed in the upper and lower faces of the thrust plate 7. The thrust plate 7 is placed in an annular recess 10 which is defined by a step portion 8a formed in the sleeve 8, and the lower face 9a of a ring member 9 fixed to the upper end portion of the sleeve 8 and constituting a part of the sleeve 8.
The embodiments shown in Figs. 1 and 3 may be modified so that the dynamic pressure grooves 7a are not formed in the upper and lower faces of the thrust plate 7 fixed to the shaft 3, and dynamic pressure grooves (not shown) are formed on the step portion 8a of the sleeve 8, and the lower face 9a of the ring member 9 fixed to the upper inner end portion of the sleeve 8 and constituting a part of the sleeve 8.
As described above in detail, according to the dynamic pressure bearing device of the invention, in both the cases where the shaft is rotated and where the sleeve is rotated, the thrust plate is sandwiched by the thrust bearing and the clearance between the components can be made smaller.
Therefore, it is possible to ensure not only the accuracy in a lateral direction during rotation but also the accuracy in a vertical direction. When the thrust dynamic pressure bearing due to the thrust plate fixed to the shaft is disposed at or in the vicinity of the center of gravity of the rotary member, the degree of deflection caused by the moment load can be reduced.
Claims (6)
1. A dynamic pressure bearing device in which a shaft
is fixed to one of stationary and rotary members, a sleeve
is fixed to the other one of said stationary and rotary
members, said shaft is fitted into said sleeve, and a
dynamic pressure bearing is formed between said shaft and
said sleeve, wherein a thrust plate is fixed to said shaft,
said thrust plate is placed in an annular recess space
formed in an inner face of said sleeve, and a thrust dynamic
pressure bearing is formed between each of upper and lower
faces of said thrust plate and said annular recess.
2. A dynamic pressure bearing device according to claim
1, wherein said thrust dynamic pressure bearings are formed
by forming dynamic pressure grooves in said upper and lower
faces of said thrust plate.
3. A dynamic pressure bearing device according to claim
1, wherein said thrust dynamic pressure bearings are formed
by forming dynamic pressure grooves in upper and lower faces
of said annular recess of said sleeve.
4. A dynamic pressure bearing device according to claim 1,
3 2 orjwherein said upper and lower faces of said thrust plate
extend so as to be perpendicular to an axis of said shaft
and in parallel with upper and lower faces of said annular
recess of said sleeve.
5. A dynamic pressure bearing device comprising a shaft rotatable about an axial direction relative to a sleeve with a dynamic pressure bearing formed therebetween, and a thrust dynamic pressure bearing provided between the shaft and sleeve and comprising an annular thrust plate rotating about the axial direction within and relative to an annular recess with the thrust dynamic pressure bearing formed between upper and lower surfaces of the thrust plate and the annular recess.
6. A dynamic pressure bearing device substantially as hereinbefore described with reference to Figures 1 and 2 or Figures 3a and 3b of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20761595A JPH0932850A (en) | 1995-07-20 | 1995-07-20 | Dynamic pressure bearing device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9614948D0 GB9614948D0 (en) | 1996-09-04 |
| GB2303413A true GB2303413A (en) | 1997-02-19 |
| GB2303413B GB2303413B (en) | 1999-09-22 |
Family
ID=16542731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9614948A Expired - Fee Related GB2303413B (en) | 1995-07-20 | 1996-07-16 | Dynamic pressure bearing device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0932850A (en) |
| GB (1) | GB2303413B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10037077A1 (en) * | 2000-07-27 | 2002-02-28 | Paul Mueller Gmbh & Co Kg | Dynamic gas bearing of a motor spindle with ventilation |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114635872B (en) * | 2022-04-19 | 2023-09-05 | 广东美芝制冷设备有限公司 | Fan and cleaning equipment |
| CN114790996B (en) * | 2022-04-19 | 2024-02-06 | 广东美芝制冷设备有限公司 | Blower and cleaning device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2043182A (en) * | 1979-01-16 | 1980-10-01 | Matsushita Electric Ind Co Ltd | Bearing assemblies |
| EP0038602A1 (en) * | 1980-04-18 | 1981-10-28 | Ihc Holland N.V. | An axial bearing |
| US4445793A (en) * | 1981-09-18 | 1984-05-01 | Matsushita Electric Industrial Co., Ltd. | Bearing |
| US5423612A (en) * | 1994-09-16 | 1995-06-13 | Quantum Corp. | Hydrodynamic bearing and seal |
| US5487608A (en) * | 1994-07-22 | 1996-01-30 | Seagate Technology, Inc. | Single plate hydrodynamic bearing with self-balancing fluid level and fluid circulation |
| US5516212A (en) * | 1995-09-18 | 1996-05-14 | Western Digital Corporation | Hydrodynamic bearing with controlled lubricant pressure distribution |
| GB2298464A (en) * | 1995-02-15 | 1996-09-04 | Koyo Seiko Co | Spindle unit having dynamic pressure bearings |
-
1995
- 1995-07-20 JP JP20761595A patent/JPH0932850A/en active Pending
-
1996
- 1996-07-16 GB GB9614948A patent/GB2303413B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2043182A (en) * | 1979-01-16 | 1980-10-01 | Matsushita Electric Ind Co Ltd | Bearing assemblies |
| EP0038602A1 (en) * | 1980-04-18 | 1981-10-28 | Ihc Holland N.V. | An axial bearing |
| US4445793A (en) * | 1981-09-18 | 1984-05-01 | Matsushita Electric Industrial Co., Ltd. | Bearing |
| US5487608A (en) * | 1994-07-22 | 1996-01-30 | Seagate Technology, Inc. | Single plate hydrodynamic bearing with self-balancing fluid level and fluid circulation |
| US5423612A (en) * | 1994-09-16 | 1995-06-13 | Quantum Corp. | Hydrodynamic bearing and seal |
| GB2298464A (en) * | 1995-02-15 | 1996-09-04 | Koyo Seiko Co | Spindle unit having dynamic pressure bearings |
| US5516212A (en) * | 1995-09-18 | 1996-05-14 | Western Digital Corporation | Hydrodynamic bearing with controlled lubricant pressure distribution |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10037077A1 (en) * | 2000-07-27 | 2002-02-28 | Paul Mueller Gmbh & Co Kg | Dynamic gas bearing of a motor spindle with ventilation |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9614948D0 (en) | 1996-09-04 |
| GB2303413B (en) | 1999-09-22 |
| JPH0932850A (en) | 1997-02-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20150716 |