JPS60175820A - Squeeze bearing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a bearing that enables mutual linear motion between a pair of bearing members, and in particular, to a bearing that enables relative motion of the bearing members with almost no friction. A tubular bearing member that produces relative radial vibrations between a rod-shaped bearing member and a surrounding sleeve-shaped bearing member to compress and depressurize a thin film of gas or liquid between the bearing members to create a compressive bearing effect. This invention relates to a compressed bearing device.

[Prior art]

The basic principle of compression type bearings is
of he ASME Journal,, of B
a5ic Engineering, June 6.19
CompreSsib by 64 E, O, 5albu
le 5queeze Films and Sque
ezeBearings”.

Recently, cylindrical compression bearings have been proposed as bearing elements for magnetic transducer carriage assemblies of disk file transducer positioning devices. Such a positioning device quickly and accurately positions a magnetic lance positioner to a specific track on a magnetic disk. For positioning operation, approximately 2.54cm to 5.0cm
It involves linear movement with very high accuracy over a movement range of 8 cm (~2 inches). 1 - The lance pump is attached to a spatula/arm attached to a moving coil of a voice coil actuator. The coil and head arm are carried by a carrier assembly which precisely guides the spatula 1 and the coil while the coil and head move along a straight path between track addresses. The spacing between the head and the disk must be precisely controlled because it is critical to satisfactorily writing and reading data to and from the disk. In addition, in order to accurately write and read data, it is necessary to maintain the recording gap of the magnetic head at a constant angle with respect to the center line of 1 to 4 lacs.

Although prior art tubular compression bearing arrangements are capable of translating across the disk at the required m-angle without static friction problems, they suffer from pitching (p) of the bearing.
It is necessary to reduce the rotational or torsional stiffness of the bearing in order to improve its stability and yaw stability.

FIG. 2 shows a compressed bearing 10 according to the prior art.

Such a bearing 10 includes a fully cylindrical rod-shaped bearing member 12 made of a suitable material, such as stainless steel.

Surrounding the bearing member 12 is a bending element 1
- a sleeve-shaped bearing member 1 consisting of a tube of piezoelectric ceramic, such as a zirconium titanate button (1) ZT) supported on an inner tube of molybdenum to form a transducer;
It is 4. Typically, the radial gap between bearing members 12 and 14 is 0. OO'1 cm. A pair of metal thin film electrodes 16 are attached to the outer surface of the sleeve-shaped bearing member 14, and the electrodes 16 are connected to an AC power source 18 by a suitable conductor 20. As the power source 18 is subdivided, the sleeve-like bearing members 14 vibrate radially inward and outward, compressing and depressurizing the air or other gas or liquid in the small annular space between the bearing members 12 and 14. are carried out alternately, resulting in the well-known squeeze bearing effect. Such a bearing is stable in displacement along the Y and Z axes, in yaw motion about the Z axis, and in pitching about the Y axis. Therefore, although bearing members 2 and 14 are capable of translational movement along the Z-axis, relative rotation of bearing members 12 and 14 occurs around the Z-axis.

When such prior art compression bearings are used to locate the read/write head carriage in a magnetic disk data storage file, the read/write head carriage can be moved very precisely over a limited range. It needs to be able to move and the read/write head needs to be maintained in a substantially constant plane parallel to and adjacent to the taster surface. Therefore, it is necessary to prevent the bearing member supporting the read/write head from rotating about the translational axis.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a compression bearing device that suppresses relative rotation between a rod-shaped bearing member and a sleeve-shaped bearing member. ! [Means for solving the problem] A non-circular outer circumferential surface is formed on at least a portion of the cylindrical outer surface of the rod-shaped bearing member, and a non-circular outer circumferential surface is formed on at least a portion of the cylindrical inner surface of the hollow portion of the sleeve-shaped bearing member. When a circular inner circumferential surface is formed, a considerable degree of torsional stiffness is obtained.

In this specification, the term "cylindrical" refers to a shape that does not necessarily have to be a perfect circle but can be expressed by two straight lines intersecting a closed curve. Outer surface of rod-shaped bearing member and sleeve shape Φ+h
The inner surface of the receptacle does not have to be cylindrical in all parts.

A compression bearing device according to the present invention includes a sleeve-shaped bearing having a hollow portion in which a first non-circular inner circumferential surface is formed and a shaft extending through the hollow portion.

The rod-shaped bearing member extends through the hollow portion of the sleeve-shaped bearing member and has an outer surface with a second non-circular outer circumferential surface. At least one transducer, e.g.
Two means are provided which can be accessed by or form part of either the sleeve-shaped bearing member or the rod-shaped bearing member. As a result, a load supporting force is generated in the compression bearing device formed between the two bearing members. What is important is that since the circumferential surface of the bearing member is non-circular, the relative rotation of both bearing members about 112th I+h is suppressed (resisted).

As used herein, the term "non-circular circumferential surface" refers to a shape within the sleeve-shaped bearing member such that the relative rotation between the sleeve-shaped bearing member and the rod-shaped bearing member is limited to a range of less than ] degrees. This refers to the relationship between the circumferential surface and the outer circumferential surface of the rod-shaped bearing member.

Depending on the application of the compression bearing device, either the sleeve-shaped bearing member or the rod-shaped bearing member can be fixed, and the other can be moved in translation. The sleeve-shaped bearing member can be made in part from piezoelectric material, for example.

The rod-shaped bearing member may consist of a continuous block of piezoelectric material, or it may consist of a hollow body with a piezoelectric transducer provided on its inner surface. In some embodiments, both the sleeve bearing member and the bar bearing member are formed at least in part from piezoelectric material and are driven at the same or different frequencies.

In a preferred embodiment of the invention, the rod-shaped bearing member and the sleeve-shaped bearing member are equally spaced from each other over their entire circumference. However, if a plurality of segment pairs having substantially the same geometric shape and protruding toward the periphery are juxtaposed on the circumferential surface of the bearing member, local supporting force can be generated and the relative Transducer elements are disposed in the segments such that relative radial vibration occurs between the two segments primarily to prevent rotation. As used herein, "geometrically similar" means that one closed curve and another closed curve or one portion of a curve and another portion of a curve have substantially the same shape but the overall size or position is say different things.

Instead of piezoelectric transducers, electrostrictive, magnetostrictive, and electromagnetic transducers can be used to create the necessary relative vibrations. Although the shape of the bearing member is preferably square or rectangular, it is not necessarily necessary to take such a shape; for example, other non-circular peripheral surfaces such as an ellipse, a triangle, a hexagon, a pentagon, a D-shape, etc. can be adopted.

〔Example〕

1, 3A and 3B show a general embodiment of a compressor bearing arrangement according to the invention. The rod-shaped bearing member 22 is formed with a cylindrical outer surface 24 that abuts an arbitrary non-circular outer peripheral surface 26 . A sleeve-shaped bearing member 28 in which a cylindrical hollow portion 30 having a non-circular inner circumferential surface 32 is formed is a rod-shaped bearing member 2
It is slidably attached to 2. The inner circumferential surface 32 has a geometrically similar shape to the outer circumferential surface 26. 1st
As shown, bearing members 22 and 28 have a common axis 34. As shown in FIG. 3A, the gap between bearing members 22 and 28 is preferably uniform over the entire circumference.

Although a single piezoelectric transducer can be used.

Bearing member 28 as shown in FIGS. 1 and 3A.
A plurality of lances 36 may be coupled to the outer surface 38 of the lance 36 . In the illustrated example, the rod-shaped bearing member 22 is secured to a suitable base 40. However, the sleeve-shaped bearing member 28 may be fixed and the bar-shaped bearing member 22 may be translated as shown in the embodiment of FIG. 12, which will be described later. When transducer element 36 is driven by a suitable power source, not shown, bearing member 28 vibrates radially. 1 to lance shuttle at the resonance frequency of the bearing member 28.
- When the sensor 36 is driven, a displacement sufficient to cause alternate compression and decompression of the gas in the gap between the rod-shaped bearing member 22 and the sleeve-shaped bearing member 28 is generated between the two bearing members, thereby causing a displacement between the two bearing members. No.: A local support force is generated in the compressed bearing member that is formed. Importantly, the non-circular circumferential surface of the bearing parts allows for almost frictionless translational movement between the bearing parts along their common axis, while also allowing relative movement around said common axis. It is possible to prevent rotation.

FIG. 3B shows another general embodiment of the compression bearing device of the present invention in which the bar bearing member 22 is hollow and has a central hole 42 in which a plurality of piezoelectric transducers 44 can be accommodated. . In this example, the sleeve-shaped bearing member 28 is fixed to a suitable base body 46 and the bar-shaped bearing member 22
is preferably capable of axial translation. By driving the transducer 44 at the resonant frequency of the bearing member 22, relative rotation between the bearing members is suppressed while producing the desired compressive bearing effect in the same manner as described above.

In the general embodiment of the compressor bearing device according to the invention described above,
Although the radial gap between the bearing members 22 and 28 is made equal over the entire circumference, this need not necessarily be the case. FIG. 4 is a sectional view showing a compression bearing device in which the rod-shaped bearing member 50 has an octagonal cross-section and the sleeve-shaped bearing member 48 has a square cross-section. On the inner circumferential surface of the bearing member 48 and the outer circumferential surface of the bearing member 50, a plurality of segments 5 protruding toward the periphery so as to have geometrically similar shapes are provided.
2.54.56 and 58 are juxtaposed.

The transducers 60 are mounted on the same segment of the outer surface of the sleeve-shaped bearing member 48 where the gap between the two bearing members is approximately uniform. The radial clearance between the bearing members varies considerably between the pairs of segments 1. The individual pairs of similar peripheral segments need not all have the same geometric shape, so long as the segments of each pair have a similar geometric shape.

5, 6 and 7 show very simply the operating mode of the compressor bearing arrangement according to the invention with improved torsional stiffness. The fixed rod-shaped bearing member 62 is surrounded by a movable sleeve-shaped bearing part 64 arranged coaxially therewith.
ing. For the sake of clarity, the one-herald shakers that cause relative radial vibrations between the bearing members are not shown. In a typical example, the gap between the bearing members is 0.001 cm, and the side length of the bearing member 62 is approximately 0.6 cm. When relative rotation occurs between the bearing members due to the application of torque during operation, the fifth
The uniform gap shown in the figure changes to a gap in which several wedge-shaped spaces 68 are formed between the bearing members as shown in FIG. When the clearance is reduced by 1-lux, as shown at location 70 in FIG. 6, a bearing force is created at location 70, resisting further rotation. one tenth
- If a torque of 4 is applied, bearing members 62 and 64 will come into contact as shown in FIG. In contrast to this unique mode of operation of the compressor bearing device according to the invention, the prior art compressor bearing device r1 of the type shown in FIG. Allow unlimited rounds of discussion.

FIG. 8 shows a first specific embodiment of the invention.

The rod-shaped bearing member 72 whose cross section is in the positive direction is made of, for example, glass,
It is formed from the right material such as ceramic or stainless steel by precision machining. The material used for the bearing member 72 has high hardness and low density, and is machined to have a good surface so that the bearing member can make intermittent contact without undue wear during start-stop conditions. It needs to be possible. One end of the rod-shaped bearing member 72 is fixed to a suitable support 74. - In the example, the bearing member 72
has a square cross-section of about 1 cm on a side and is of sufficient length to allow the required movement of a sleeve-shaped bearing member 76 with a square cross-section to which it is slidably mounted. The bearing member 76 is made from a material such as, for example, molybdenum and has an inner surface precision machined. - In the example, the length of the bearing member 76 is 7 cm, and the cross section is approximately 7 cm on one side]
cm square, and the wall thickness is approximately 0.1 cm.

The nominal gap between the bearing members is preferably 0°00 cm. The outer finish of the middle receiving member 76 can be ten times better than the inner finish without substantially affecting performance. However, if the difference in finish between the inner and outer surfaces is very large, the reproducibility of vibration modes of the bearing will be poor.

Four PZT transducers 78 are mounted centrally on the outside of bearing member 76 by means such as epoxy adhesive. - In the example, the length of transducer 78 is approximately 2CI11. Width is approximately ICIl+, thickness is approximately 0.08
cm. Each transducer 78 has a first electrode 80
is provided. The electrode 80 includes, for example, a pair of lead attachment pads 82 and 84 of about 0.1.3 cm.
It surrounds the end of the transuser 78 and extends across the surface in contact with the former heel receiving portion tA76 to form a. The second electrode 86 is a lead attachment member 1-.
It is attached to the outer surface of each 1-transducer 78 between pads 82 and 84. One 1 ~ Lance Juusa 78
A back electrode 88 is attached to the center of the frame.

Conductor pairs 90 and 92 are connected to a series of conductors 1 to 9 around bearing member 76.
The electrodes of the lance pump 78 are interconnected.

Another pair of conductors 94 and 96 connect electrodes 80 and 86 to an AC power source 98. Power supply 98 drives transducer 78 at the resonant frequency of bearing member 76 .

The vibration of the lance pump 78 produces sufficient radial relative vibration to produce the required compression bearing effect, but the amplitude and direction of the vibration at point 1-1 is in the longitudinal direction of the bearing section. It will be clear to those skilled in the art that it is not uniform along or all around.

Conductor 100 connects feedback electrode 88 to differential phase sensing circuit 102 . The differential phase sensing circuit 102 is configured such that the phase of the feedback signal () on the conductor 100 at the time of resonance is the same as that on the conductor 9.
The phase of the power supply 98 is adjusted so that it is 90 degrees out of phase with the drive signals 'l and 9G.

A phase-locked loop circuit maintains the bearing at the desired resonant frequency. Although it is preferred that the four transducers 78 operate at the same resonant frequency, the transducers 78 may be driven at different frequencies.

Various modifications of the embodiment shown in FIG. 8 are possible. For example, if it is necessary to translate the bearing member 72 and fix the bearing member 76, the sleeve-shaped bearing portion 447G may be moved to the node position indicated by the broken line 104 (the support body 74 may be removed). In addition, a part of the rod-shaped bearing member 72 is made of piezoelectric material, and the conductor 11 is removed at 1111 points.
0.112 to a pair of electrodes 108 of the bearing 72 using a separate AC power supply 106 connected to the rod-shaped bearing member 7
2 can also be driven. With such a configuration, the rod-shaped bearing portion JA72 and the sleeve-shaped bearing member 76 can be driven at different frequencies. Incidentally, the one-herald transformer 78 can also be formed from an electrostrictive material instead of a piezoelectric material. Moreover, it is preferable that the sleeve-shaped bearing part 476 is made of glass.

FIG. 9 shows a second specific embodiment of the present invention in which a rod-shaped bearing member 72 has a hollow structure. The rod-shaped bearing part A'72 has
A flat-sided central hole 114 into which four PzT transducers 116 are mounted using a suitable epoxy adhesive.
is formed. Although not shown, it is preferable that the lance pumps 1 to 116 are connected to a suitable power source, and the rod-shaped bearing portion 72 is fixed. In this embodiment, the bearing lug 72 may be made from continuous molybdenum with a precision polished outer surface. The sleeve-shaped bearing member 76 can be made of molybdenum, stainless steel, or the like with a precision machined inner surface. It is also possible to use bending elements of the type disclosed in Japanese Patent Application No. 57-38262. Furthermore, an electrostrictive 1-Herans pump can also be used in the embodiment of FIG.

FIG. 1O shows a third magnetically driven embodiment of the invention. The sleeve-shaped bearing member 76 is made of a suitable magnetically permeable or non-magnetic material and is inserted into the mount 1 at node lines 118 and 120.

The rod-shaped bearing part +172 is made of a non-magnetic material and is allowed to translate freely. In this embodiment, instead of using a piezoelectric or electrostrictive transducer, four plates 12 made of a magnetic material, such as ferrite, soft iron, samari-cobal or nickel, are used in this embodiment.
2 is adhered to the center of the side surface of the sleeve-shaped bearing member 76. Alternatively, 6PA strained material can also be used. As schematically shown, a sleeve-shaped bearing member 7
Four stationary electromagnets 124 are provided in the vicinity of 6, facing each magnetic plate 122, respectively. An electrical lead (not shown) extending from the electromagnet 124 is connected to an AC power source that drives the sleeve bearing member 76 at a resonant frequency.

FIG. 11 shows a fourth embodiment of the present invention in which the rod-shaped bearing member 72 is made from I) a ZT or electrostrictive rod and the outer surface is precision machined.
A specific example is shown below. The sleeve-shaped bearing member 76 can be formed from stainless steel with a precision machined inner surface. In this embodiment, the thickness of the rod-shaped bearing portion 72 is approximately 100 times the thickness of the gap between the bearing members 72 and 76. That is,
The thickness of bearing member 72 is approximately 1 cm. The compression bearing device shown in FIG. 11 is driven by a pair of electrodes 126 and 128 that are electrically connected to an AC power source (not shown) by conductors 130 and 132. FIG. 12 shows an embodiment of the present invention similar to the embodiment of FIG. 9, except that the sleeve-like bearing member 76 is fixed to a suitable base 134, while the rod-like bearing member 72 is configured to be translatable. A specific example of No. 5 is shown below.

FIG. 13 shows a sixth specific embodiment of the invention which is similar in many respects to the embodiment of FIG.

In this example, the bar bearing member 72 is fixed and includes a continuous central transducer section 138 made of glass, ceramic, or stainless steel, and a continuous central transducer section 138 made of PZT or electrostrictive material and coupled to section 140. , glass,
It includes an outer body 40 made of ceramic or stainless steel and coupled to a 1-lance user part 138. Central 1-
The length of the transducer section 138 is selected to provide the required vibration amplitude between the bearing member 72 and 7/l without overheating the transducer section I38. .

FIG. 14 shows a four-way shaft bearing material is fixed and connected to a continuous central one-hole shaft section 142 made of glass, ceramic or stainless steel and a J-shaped section 142 made of magnetostrictive material 44, such as nickel. It includes a user part 144 and an outer part 146 made of glass, ceramic or stainless steel and coupled to the lance lever part 44. A solenoid-type IW moving coil 148 connected to an AC power source (not shown) surrounds the magnetostrictive section 144. coil 14
When 8 is operating, 1 to lance adjuster section 1411
is caused to vibrate by the well-known magnetostrictive effect 3. The length of the lance lever part 144 is such that the length between the bearing parts 72 and 7[5] without overheating the lance lever part 14.4 is vibrated by the well-known magnetostrictive effect. selected to produce vibrations of the required amplitude.

Figures 1.5A to 15J illustrate various other non-circular cross-sectional shapes that can be used in rod and sleeve bearing members according to the present invention. The torsional stiffness of a compression bearing device with a given cross-sectional or circumferential shape is influenced by several factors. The resulting stiffness is the integral or sum of the stiffnesses at each point along the circumference of the bearing member, modified by the effective moment 1 - the geometric factor associated with the arm. Referring to FIG. 15A, at a particular point 1-' along the circumferential surface of the bearing member, the factors affecting the torsion stiffness are local bearings that are a function of the deflection at point P and near this point. The stiffness includes the angle b between the radius vector R from the center of the quantity to the point l) and the tangent to the point P, and the length of the radius vector R.

= In general, a given torsional stiffness decreases as the number of outwardly projecting lobes increases. This is because as the number of lobes increases, the cross-sectional shape becomes more circular and exhibits less stiffness. ] 5 r3 l
A1.pl and shown in FIG. 15c. In the cross section shown, two axes of symmetry of equal length are at 90 degrees to each other. 15th floor
), 15E and 151, the symmetry axes of the unequal lengths 2-) are at 90 degrees to each other. Figure 15G.

In the cross section shown in Figure 1511, Figure 15I and Figure 15,1, there are three axes of symmetry of equal length.

], 5A to 15J are only a few examples of suitable cross sections. It will be clear to those skilled in the art that cross-sections applicable to the present invention exist in focus. The selection of the cross-sectional geometry to be used.

Ease of producing the required surface in the production ring J1°ε.

and the degree of practicality of using piezoelectric or other one-lance pumps to drive active compression bearing members.

The technology for manufacturing sleeve-shaped bearing members with various inner circumferential surfaces from glass was published in the United States in December 1982.
CT filed I) CT/LJ S 82101,
828. According to this technology, a glass tube with an inner diameter slightly larger than the maximum diameter of the required cross-sectional shape,
A mandrel of suitable material and shape and a support for the glass tube are prepared at ζ1°. The pre-heated man 1~rel is then taken and inserted into the tube held in the tool 5, and the necessary +E+ parts are applied to the outside surface of the man 1~rel to facilitate subsequent removal. 'It can give you the release of the moon. Inside the tube 1) -1°(shi,'
Heat is applied to the tube to heat the glass to its melting point while drawing out B. The mandrel is then removed when cooled. By preparing a vacuum mold having a coefficient of thermal expansion smaller than that used for the rod-shaped bearing part H, the outer surface of the rod-shaped bearing member can be precisely formed. For example, a vacuum mold made from Invar can be used in whatever shape is needed when forming bar bearings from glass. A glass scraper inserted into such a mold and heated to its melting point expands and comes into contact with the walls of the mold, and after cooling,
It is designed with a geometric shape that perfectly matches the mold wall.

〔Effect of the invention〕

Since the present invention forms a non-circular outer circumferential surface on the rod-shaped bearing member and forms a non-circular inner circumferential surface on the sleeve-shaped bearing member, it is possible to prevent relative bending between the two members.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first general embodiment of a compression bearing device according to the present invention, FIG. 2 is a perspective view showing an example of a compression bearing device according to the prior art, and FIG. 3Δ is a line 3A in FIG. 1. -3Δ, (H> cross-sectional view,
FIG. 3B is a cross-sectional view showing a second general embodiment of the compression bearing device according to the present invention, in which the rod-shaped bearing member is hollow and several lances are formed on the inner surface of the above-mentioned portion. The figure shows a third embodiment of the compression bearing device according to the present invention in which a plurality of pairs of cuff members (a plurality of pairs are juxtaposed) protrude from the periphery so as to form substantially geometrically similar shapes to the circumferential surfaces of the rod-shaped and sleeve-shaped bearing members. Cross-sections 1, 5, 6 and 7 showing a typical embodiment show that when no torsion load is applied to the anus and when some torsion load is applied,
FIG. 8 is a perspective view showing the first specific embodiment of the compression bearing device according to the present invention; FIG. 9 is a perspective view showing a second specific embodiment of the compression bearing device according to the present invention, FIG. 10 is a perspective view showing a third specific embodiment of the compression bearing device according to the present invention, FIG. 11 is a perspective view showing a fourth specific embodiment of the compression bearing device according to the present invention, FIG. 12 is a perspective view showing a fifth J1-body embodiment of the compression bearing device according to the present invention, and FIG. FIG. 14 is a perspective view showing a seventh specific embodiment of the compression bearing device according to the present invention; FIG. 15Δ; FIG. 15B; Figure 15C, Figure 151),
Fig. 15E, No. 5 Fig. 15F, Fig. 15G, No. 15 I
Fig. 1, Fig. 15T, and Fig. 15J are explanatory diagrams showing examples of cross-sectional shapes of bearing members according to the present invention. 22... Rod-shaped bearing member, 26... Non-circular outer circumferential surface, 28... Sleeve-shaped bearing member, 32... Non-circular inner circumferential surface, 36... 1-Lanse juicer. International Business Machines Corporation Representative Patent Attorney Hitoshi Yamamoto (1 other person) FIG, 5 FIG, 6 FI, 7FIG I!
￥t Continued from page 1 @ Inventor Robert A. Ameranton Yar, [Inventor] David A. Amempson I. Orchid Drive, Salem, New York, United States (no street address) United States Two Lakes Road, South Salem, New York (no street address)

Claims (1)

[Scope of Claims] A sleeve-shaped bearing member having a hollow portion having a non-circular inner peripheral surface; a rod-shaped bearing member extending through the hollow portion and having a non-circular outer peripheral surface; A compression bearing device comprising: means for generating mutualistic 4M motion between a bearing member and the rod-shaped bearing member.