JPH02159412A - Bearing device and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To enlarge bearing supporting load and to shorten processing time with ease in mass production by varying the depths of dynamic pressure generating channels provided on the sliding surface of a bearing in the rotational direction and the center direction of a shaft. CONSTITUTION:So as to make the end surface 3a of a shaft 3 face on the sliding surface 1a of a thrust bearing 1 provided with dynamic pressure generat ing channels 2 of spiral shape formed therein, both surfaces are arranged via liquid film 4 of such as oil. When the shaft 3 is turned in A direction, fluid filled up in the dynamic pressure generating channels 2 generates pressure with pump action of channels on account of in widths and depths of channels getting smaller in the rotational direction, and a large fluid pressure is generated in the neighbor of the center part of the shaft. The thrust bearing 1 can be provided with large capacity of supporting load, and floating up quantity in axial direction of the shaft 3 etc also gets large. A metal mould having a projec tion of a pattern copied from the dynamic pressure generating channels to be formed on the thrust bearing is pressed on the sliding surface 1a of the thrust bearing 1 and thus the dynamic pressure generating channels 2 can be easily formed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a hydrodynamic bearing device, and in particular to a bearing with hydrodynamic grooves suitable for a cylinder bearing of a magnetic recording/reproducing device (hereinafter referred to as VTR). Regarding the device and its manufacturing method.

[Conventional technology]

Conventional hydrodynamic thrust bearings are described in 1. Journal of the Japan Society of Mechanical Engineers, Vol. 89,
As described in No. 812 (1986), pages 58 to 63, a spiral dynamic pressure generating groove was provided on the sliding surface. The dynamic pressure generating groove had a rectangular cross section, and the groove depth was uniform over the entire sliding surface.

Another example of devising the bearing surface is JP-A-52-
There are techniques described in JP-A No. 133451 and JP-A-61-165018, respectively.

On the other hand, the dynamic pressure generating grooves were formed by photo-etching as described in Japanese Patent Publication No. 62-49352.

[Problem to be solved by the invention]

In the above conventional technology, the depth of the spiral dynamic pressure generating groove provided on the sliding surface of the thrust bearing is uniform over the entire sliding surface, so the pumping action of the groove as the shaft rotates cannot be obtained sufficiently. Ta. Therefore, there is a problem in that the dynamic pressure generated in the bearing portion is small and a large supporting load capacity cannot be obtained. Further, since the axial flying height of the member supported by the bearing portion is also small, there is a problem that torque loss increases and the amount of wear on the bearing sliding surface increases.

In recent years, there has been a strong desire to reduce the size of products, especially in VTRs and the like, so there has been a demand for ways to make the magnetic head mounting cylinder, which is a central component, as small as possible. The inventor determined that reducing the thickness (lower height) of thrust bearings and shafts, for example, would be an effective means of solving this problem. I realized that in order to have high hopes, it was necessary to fundamentally review the groove shape and its manufacturing method. Prior to the present invention, no effective means for solving this problem had been found.

On the other hand, the dynamic pressure generating grooves of the thrust bearing have conventionally been formed by photo-etching, which poses a problem of high manufacturing costs due to difficulties in mass production and long processing times.

An object of the present invention is to provide grooves that generate large dynamic pressure on the sliding surface of a bearing, and to process the dynamic pressure generating grooves using a method that is easy to mass produce and takes a short processing time, thereby improving the above-mentioned conventional technology. An object of the present invention is to provide a bearing device that solves problems.

Another object of the present invention is to provide a hydrodynamic bearing device that can support a large bearing load and achieve stable support.

[Means to solve the problem]

The above object is achieved by varying the depth of the dynamic pressure generating grooves provided on the sliding surface of the bearing with respect to the rotation direction and center direction of the shaft.

Further, the dynamic pressure generating groove is formed by a coining process in which a mold having a convex portion whose shape is inverted is pressed against the sliding surface of the bearing. This achieves mass production of bearings.

Briefly speaking, the features of the bearing device of the present invention are as described above, but the structure also has one of the following features.

(1) In a bearing device in which a rotating member and a stationary member are arranged opposite to each other with a liquid film interposed therebetween, and a groove is formed on the opposing surface of the rotating member, the groove is formed along the groove line and on the opposing surface of the rotating member. It is formed gradually deeper in the direction of rotation.

(2) In a bearing device in which a rotating member and a stationary member are arranged facing each other with a liquid film interposed therebetween, and a groove is formed on the opposing surface of the stationary member, the groove is formed along the groove line and on the rotating member. Form gradually shallower in the direction of rotation.

(3) In the bearing device of (1) or (2) above, the shallower the groove, the smaller the cross-sectional area, and the deeper the groove, the larger the cross-sectional area. Note that the cross-sectional area is the cross-sectional area in the width direction of the groove.

(4) In the bearing device according to any one of (1) to (3) above, the groove depth changes continuously.

(5) In the bearing device according to any one of (1) to (4) above, the rotating part or rather the stationary member is a thrust bearing.

(6) In the bearing device according to any one of (1) to (4) above, the stationary portion or the rotating member is a radial bearing.

(7) A thrust bearing in which a stationary member having a spiral groove on its sliding surface supports a rotating member disposed opposite to the sliding surface of the stationary member in a floating manner via a fluid film; The depth of the groove is gradually reduced along the length of the groove.

(8) In a thrust bearing in which a stationary member having a spiral groove on its sliding surface supports a rotating member disposed opposite to the sliding surface of the stationary member in a floating manner via a fluid film, the groove depth is is made shallow with respect to the rotational direction of the rotating member.

(9) In the thrust bearing device described in (7) or (8) above, the groove is formed on the rotating member side instead of on the stationary member side, and the tendency of the groove depth is reversed.

(10) A radial bearing is formed in the relationship between the stationary member and the rotating member according to any one of (7) to (9) above.

(11) A groove for generating dynamic pressure is formed in at least one of the rotating member or a stationary member disposed opposite to the rotating member, and a fluid is interposed between the facing surfaces of the rotating member and the stationary member. In a hydrodynamic bearing device that generates dynamic pressure by rotation of the rotating member and supports the rotating member, the groove is open on the advancing side with respect to the direction of relative movement between the rotating member and the stationary member. It consists of a pressure increasing groove that becomes narrower toward the rear, and a pressure accumulating groove that connects the narrower parts of the pressure increasing grooves, and each part extends in the longitudinal direction of the groove. changing depth.

(12) In the hydrodynamic bearing device according to (11) above, a plurality of the grooves for generating dynamic pressure are formed in at least one of the rotating member or the stationary member in the relative movement direction, and The formation pitch of the grooves is approximately equal.

(13) In the hydrodynamic bearing device according to (11) or (12) above, the groove for generating dynamic pressure is formed in at least one of the rotating member or the stationary member in a direction perpendicular to the direction of relative motion. Multiple groups have been formed.

(14) In the hydrodynamic bearing device described in (11) above, the pressure accumulating groove portion is formed as a groove parallel to the rotation axis.

(15) In the hydrodynamic bearing device described in (11) above.

The minimum pitch (2uz
) and the maximum pitch (2l2) is between 0.3 and 0.8
It is between.

(16) In the hydrodynamic bearing device described in (11) above, the fluid is a liquid.

(17) In the hydrodynamic bearing device described in (11) above, the fluid is a gas.

(18) Fitting a shaft member and a housing member, interposing a fluid between opposing surfaces of a surface of the shaft member and a receiving surface of the housing member, and displacing at least one of the shaft member or the receiving surface of the housing member. In a hydrodynamic bearing device that supports a rotating member through relative rotational movement between the shaft member and the housing member, the groove for generating dynamic pressure is formed on one side of the bearing. includes two inclined grooves that are open on the upstream side with respect to the direction of the fluid flow due to the relative rotational movement of the shaft member and the housing member, and that gradually become narrower toward the downstream side; and the two inclined grooves. The narrowest part is formed by a groove part communicating in a direction perpendicular to the relative rotational movement, and the depth of each part changes in the length direction of the groove.

(19) In the hydrodynamic bearing device described in (18) above, the shaft member is the rotating side member, and the groove for generating the dynamic pressure is formed on the surface of the shaft member (2) (20) (1)
In the hydrodynamic bearing device described in 8), the shaft member is the rotating member, and the groove for generating dynamic pressure is formed in the receiving surface of the housing member.

(21) In the hydrodynamic bearing device according to (18) above, the housing member is the rotating member.

The groove for generating dynamic pressure is formed in the receiving surface of the housing member.

(22) In the hydrodynamic bearing device described in (18) above, the housing member is the rotating member, and the groove for generating the dynamic pressure is formed in the shaft member.

(23) In the hydrodynamic bearing device according to any one of (18) to (22) above, the groove for generating dynamic pressure is.

A plurality of them are formed in the direction of the relative rotational movement, and the pitches between them are approximately equal.

(24) In the hydrodynamic bearing device according to any one of (18) to (23) above, the groove for generating dynamic pressure.

A plurality of sets are formed in the direction of the rotation axis.

(25) In the hydrodynamic bearing device described in (18) above, the ratio of the minimum value to the maximum value of the distance between the two inclined groove portions is between 0.3 and 0.8.

(26) In the hydrodynamic bearing device described in (18) above, the fluid is gas.

(27) In the hydrodynamic bearing device described in (18) above, the fluid is a liquid.

(28) In the hydrodynamic bearing device described in (18) above, the hydrodynamic pressure generating groove is arranged in the hydrodynamic bearing device facing the longitudinal end surface of the shaft member or the longitudinal end surface of the shaft member. Formed on the receiving surface of the housing member.

(29) It has at least two opposing surfaces, these surfaces are arranged close to each other, a lubricating body is filled between these surfaces, and the lubricating body enters the gap between these surfaces due to relative movement of these surfaces. In a hydrodynamic bearing device that generates pressure and supports opposing surfaces that move relative to each other in a non-contact state using this pressure, at least one of the opposing surfaces that move relatively moves in the direction of relative movement. Is the forward side open and the rear side closed? Further, a series of grooves or protrusions are provided whose angle from the direction of relative motion becomes larger toward the rear, and the depth of the grooves or the height of the protrusions is varied in the length direction, and these are placed on the surface facing the relative motion. Install multiple pieces in parallel.

(30) In the hydrodynamic bearing device described in (29) above, the series of grooves or protrusions are formed in a plurality in the direction of relative movement and at approximately equal intervals.

(31) In the hydrodynamic bearing device described in (29) or (30) above, the series of grooves or protrusions are formed in a plurality of sets in a direction perpendicular to the direction of relative motion.

(32) In the hydrodynamic bearing device described in (29) above, the portion of the series of grooves or protrusions where the angle increases is orthogonal to the direction of relative motion.

(33) In the hydrodynamic bearing device described in (29) above, the length of the portion of the series of grooves or protrusions where the angle increases and the distance between the portions closest to the advancing side with respect to the direction of relative motion. The ratio is between 0.3 and 0.8.

(34) In the hydrodynamic bearing device described in (29) above.

The lubricant is a liquid.

(35) In the hydrodynamic bearing device described in (29) above.

The lubricating body is a gaseous lubricating body.

(36) In the hydrodynamic bearing device described in (29) above.

The portion where the angle of the series of grooves or protrusions increases includes a straight or curved portion substantially perpendicular to the direction of relative movement.

(37) In a hydrodynamic bearing device having a rotating part and a fixed part supporting the rotating part, the rotating part with respect to the fixed part is inclined with respect to the rotation direction, and the rotating part is inclined with respect to the rotation direction, and the upstream side with respect to the direction of fluid flow. Two inclined grooves or protrusions that are open on the side and gradually narrow toward the downstream side, and a straight groove or protrusion perpendicular to the direction of rotation are connected, and the groove depth or the protrusion height is 4 or varying in the length direction of the protrusion, and includes a bearing section in which a plurality of these are arranged side by side on surfaces facing relative motion.

(38) In the hydrodynamic bearing device described in (37) above.

The bearing portion is provided on a radial surface of the rotating portion.

(39) In the hydrodynamic bearing device described in (37) above.

The bearing portion is provided on a thrust surface of the rotating portion.

(40) In the hydrodynamic bearing device according to (37) above, the ratio between the minimum value and the maximum value of the distance between the two inclined grooves or the protrusions is from 0.3 to 0.8. There is.

(41) In the hydrodynamic bearing device described in (27) above, the fluid is a liquid or gaseous lubricant.

(42) In a hydrodynamic bearing device used in a device that performs magnetic recording and reproducing by winding a magnetic tape around the rotating portion and having a rotating portion having a magnetic head and a fixed portion supporting the rotating portion, the rotating portion has a rotating portion that supports the rotating portion. A groove for generating dynamic pressure is formed in the surface of the fixed part facing the rotating part or the rotating part, and a fluid is interposed between the facing surfaces between the rotating part and the fixed part, so that the rotation of the rotating part The rotating part is supported by generating dynamic pressure, and the groove for generating dynamic pressure is open on the advancing side with respect to the direction of relative movement between the rotating part and the fixed part due to the rotation of the rotating part, and the groove is open at the rear. It is characterized by consisting of two grooves that become narrower as they go along, and a groove that communicates between the narrower parts of the grooves, and that the depth of each part varies along the groove line. Dynamic pressure type hydrodynamic bearing device.

Now, in the above-mentioned bearing device of the present invention, the meaning of "groove length method" or "along the groove line" is, respectively, as described in the embodiments described below. This refers to the length direction. Therefore, the present invention does not apply to grooves in which the bottom surfaces of the grooves are only sloped when the cross section of each part is cut, but there is no change in the length direction.

It is preferable that the grooves of the present invention are formed uniformly over substantially the entire surface of the sliding surface (opposing surface), but such a groove shape may be combined with a groove whose depth does not change, or the depth of the groove may be Changes are not limited to continuous changes, but can also be gradual.

The method for manufacturing the grooves for each of the bearings described above is to press a mold having a convex portion to which the shape of the groove is transferred onto the substrate before processing, which will become the groove forming surface of the stationary part, or rather, the rotating member. Most preferably, it is formed by coining. Further, it is preferable that the mold used for this is formed of materials having different modulus of longitudinal elasticity to form a groove of an arbitrary groove depth. Note that the present invention also extends to molds used in these manufacturing methods.

Further, as an example of a product to which the present invention is applied, there is an apparatus that includes a rotating section having a magnetic head and a fixed section that supports the rotating section, and performs magnetic recording and reproducing by winding a magnetic tape around the rotating section. ) to (5) or (7) to (41) is applied to a thrust bearing, the thrust bearing is incorporated into a rotating cylinder, and the end surface thereof faces the sliding surface of the thrust bearing. The shaft is arranged as shown in FIG. Examples include those applied to fixed parts.

[Effect]

Since the principle of how grooves affect dynamic pressure is the same for thrust bearings and radial bearings, for convenience of explanation and understanding, the thrust bearing will be explained first as an example. Incidentally, since whether it is rotating or stationary (fixed) is a relationship of relative positions, this relationship may be reversed.

When the depth of the spiral dynamic pressure generating groove provided on the sliding surface of the thrust bearing is made shallow continuously in the direction of rotation and the center of the shaft, the cross-sectional area of the groove decreases in the direction. Therefore, the lubricant such as oil disposed between the shaft and the thrust bearing is enhanced by the pumping action accompanying the rotation of the shaft, generates a large pressure and forms a fluid film, resulting in a large supporting load capacity. It will be done. Similarly, since the axial flying height of the support member in the bearing section increases, loss torque decreases and the amount of wear on the bearing sliding surface also decreases.

Furthermore, if the measures described in (11) to (42) above are taken, the grooves or protrusions of the bearing device will generate dynamic pressure as the fluid pressure increases along the grooves or protrusions due to the rotational movement of the rotating member. . Then, the pressurized fluid is held by the groove or the protrusion that communicates between the two inclined grooves. This allows a high bearing support load to be obtained, and
Even when starting and stopping, fluid can easily enter between the facing surfaces of the rotating member and the stationary member, eliminating problems caused by contact.

On the other hand, if the dynamic pressure generating groove is formed by pressing a mold having the above shape onto the sliding surface of the thrust bearing, the mold will have a concave cross section due to elastic deformation. As a result, it is possible to easily fabricate a thrust bearing in which the depth of the groove is continuously shallow in the direction of rotation and the center of the shaft.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a thrust bearing according to an embodiment of the present invention, and FIG. 2 is a front view thereof. As shown in the figure, a spiral dynamic pressure generating groove 2 is provided on the sliding surface 1a of the thrust bearing 1. The dynamic pressure generating groove 2 has a large number of grooves of the same shape arranged regularly, and the width of each part corresponds to the rotation direction A of the shaft.
is continuously decreasing. Further, as shown in FIG. 1, the cross section of the groove is rectangular, and the groove depth h becomes continuously shallower in the rotational direction A of the shaft. Therefore, in the cross section of the thrust bearing, the groove depth at the inner circumference is shallower than at the outer circumference, as shown in FIG.

The thickness of the base (disk) of the thrust bearing 1 in this example is 1
．． 8 countries, the diameter is 15ffII+, and the present invention is particularly effective in application to such ultra-thin thrust bearings. The depth h of the groove 2 in this example is 5 μm at the maximum location and 2 μm at the minimum location, and the minimum location opens into the central depression 2a. The diameter of the recessed portion 2a is 0.5 m. The width d of the part of the groove 2 that opens into the recessed part 2a is 0.2 to 0.3.
m, and on the other hand, the maximum medium C of each part 2 is 1.8 m+.

Next, the operation of this embodiment will be explained.

As shown in FIG. 3, an end surface 3a of the shaft 3 is attached to the sliding surface 1a of the thrust bearing 1 in which a spiral dynamic pressure generating groove 2 is formed.
The two are arranged with a fluid film 4 of oil or the like interposed therebetween so that they face each other. In this example, oil with a viscosity of around 40 Stix is used. When the shaft 3 is rotated in the input direction in this state, the fluid filling the dynamic pressure generating groove 2 will flow into the groove because the groove has a spiral shape and the width is smaller with respect to the rotation direction. Pressure is generated by the pump action of At this time, the dynamic pressure generating groove 2
Since the depth of the shaft is also made shallow with respect to the direction of rotation of the shaft, the pumping action is facilitated, and a large fluid pressure is generated near the center of the shaft as shown in FIG. As a result, the thrust bearing 1 can obtain a large supporting load capacity, and
The axial flying height of @3 etc. also increases.

Further, the dynamic pressure generating grooves whose groove depth becomes shallower continuously in the direction of rotation of the shaft as described above can be formed into a tapered shape as shown in FIG. 4 or in a pattern as shown in FIG. It has the same effect as the dynamic pressure generating groove. It is also effective to form the groove as shown in FIG. Each part 2 formed on the sliding surface 1a of the thrust bearing shown in FIG.
It is composed of o. Even in such a thrust bearing, the allowable bearing support load increases and stable support can be achieved.

The dynamic pressure generating grooves as described above can be easily formed by the method shown in FIG. In the figure, mold 5
has a convex portion 5a having a pattern that is a transfer of the dynamic pressure generating groove formed on the thrust bearing. Therefore, the convex portion 5a of the mold 5 is pressed against the sliding surface 1a of the thrust bearing 1 to form the dynamic pressure generating groove 2 on the sliding surface. Note that the convex portion of the mold is processed to have a uniform height over the entire area.

When the dynamic pressure generating groove of the thrust bearing is coined in the above state, the surface pressure distribution of the mold becomes higher at the inner circumference than at the outer circumference, as shown in FIG. Along with this, the elastic deformation of the mold becomes larger at the inner circumference than at the outer circumference, as shown in FIG. Therefore, as shown in FIG. 1, the thrust bearing can be formed with a dynamic pressure generating groove whose groove depth becomes continuously shallower in the direction of rotation of the shaft.

Even when using a mold in which the convex portion has a uniform height over the entire region as described above, it is possible to easily form a dynamic pressure generating groove in which the groove depth changes continuously due to elastic deformation of the mold.

In addition, by selecting various materials with different modulus of longitudinal elasticity as the material for the mold, we can create dynamic pressure generating grooves with different amounts of elastic deformation of the mold and different groove depth ratios between the outer circumference and the inner circumference. Can be molded.

In this example, the height of the convex part of the mold is uniform throughout the entire area, but by partially changing the height of the convex part, it is possible to mold a dynamic pressure generating groove with an arbitrary groove depth. Can be done.

According to this embodiment, since the depth of the dynamic pressure generating groove is made shallow with respect to the rotational direction of the shaft, the pumping action of the groove is promoted, and a large supporting load capacity and axial flying height are obtained. be able to. Also.

The dynamic pressure generating grooves described above can be easily formed by pressing a mold having a convex portion in which the groove shape is transferred onto the sliding surface of the thrust bearing, so the processing time is significantly reduced compared to photo etching. Can be shortened. Furthermore, when the thrust bearing of the present invention is used in the cylinder portion of a VTR, a large supporting load capacity and axial flying height can be obtained, so that the rotational load torque can be reduced.

In the above embodiments, the grooved thrust bearing is used as a stationary member, but it can also be applied to a stationary member since it has the same effect relative to the corresponding member.

FIG. 10 is a perspective view of a magnetic recording/reproducing apparatus to which the present invention is applied, and 7 shows the entire device, with the outer box partially transparent in the figure so that the cylinder 8 can be seen. FIG. 11 shows an example of this cylinder 8.

In the example shown in FIG. 11, a grooved thrust bearing is applied to the rotating member. In this figure, 9 is a motor, 10 is an upper cylinder, and 11 is a lower cylinder. A thrust bearing with a dynamic pressure generating groove formed on its sliding surface is connected to the upper cylinder so that the sliding surface faces the shaft 3. has been done. In this state, the upper cylinder 10 is moved by the driving force of the motor 9.
When the thrust bearing 1 is rotated, the thrust bearing 1 also rotates, and accordingly, the groove surface also rotates, and fluid pressure is generated by the pumping action of the dynamic pressure generating groove, and the upper cylinder is floated and supported in the axial direction.

A thrust bearing to which the present invention is applied as described above.

Since a large flying height can be obtained, a VTR cylinder unit with small rotational load torque can be realized.

12 and 13 schematically show how grooves are formed in the present invention in the relationship between a stationary member and a rotating member.
The figure shows the relationship between the groove depth and the direction of rotation in the case of a radial bearing. Incidentally, in the radial bearing, instead of grooving the shaft member, the inner surface of the outer cylinder, which is the opposing member, may be grooved. As both figures show, rotation and rest are relative. Further, in the present invention, the relationship of being shallow (deep) in the rotation direction is defined by FIGS. 12 and 13.

FIG. 14 shows another embodiment of the present invention, which is an embodiment in which the present invention is applied to a radial bearing as a rotation recording mechanism section of a VTR.

The rotary recording mechanism in FIG. 14 includes a rotary cylinder 13 and a head 14 installed at the outer peripheral end of the rotary cylinder 13 and used for writing signals or reading signals recorded on a tape (not shown). Normal 2
The above is provided. ), a fixed cylinder 15, and a shaft 1 that stands upright from the fixed cylinder 15 and fits into the rotating cylinder 13.
6, a motor (stator 17 and rotor 18) that generates rotational driving force, and a non-contact signal transmission section (stator 19) for transmitting and receiving signals between the head 14 and a signal processing section (not shown). and the rotor 20 corresponds to this. One end of the shaft 16 is fixed to a hole provided in the center of the fixed cylinder 15 by press fit, shrink fit, or the like. The other end of the shaft 16 is inserted into a hole in a bearing housing 21, which is a bearing provided in the center of the rotating cylinder 13, with a small gap therebetween. As a result, the rotating cylinder 13 becomes rotatable around the shaft 16, and a radial bearing 12 is formed between the rotary cylinder 13 and the shaft 16. A thrust bearing plate 23 for forming a thrust bearing device with the end surface 22 of the shaft 16 is attached to one end (the upper end in the figure) of the bearing housing 21 by screws. This restricts the vertical position of the rotary cylinder. A head 14 is attached to the rotating cylinder 13 via a head base 24, and the head 14 is arranged so as to slightly protrude from the outer peripheral surface 25 of the rotating cylinder 13. In addition, the rotating cylinder 13
is provided with a rotating side transmitting/receiving coil 20 for transmitting a signal read by the head 14 to the stationary member side, or for transmitting a signal sent from the stationary member side to the head 14. A stationary side transmitting/receiving coil 19 is provided in the fixed cylinder 15 so as to face this coil 20 . Furthermore, the rotating cylinder 13 and the fixed cylinder 15 have
A rotor 18 and a stator 17 of the motor are installed facing each other.

The apparatus shown in FIG. 14 rotates the rotary cylinder 13 by a motor (18, 17), and the outer circumferential surface 25 of the rotary cylinder 13 is
The head 14 also has the function of writing signals onto a magnetic tape (not shown) helically wound around the outer circumferential surface 26 of the fixed cylinder 15 and reading signals recorded on the magnetic tape. When recording with the head 14, the track width of the magnetic tape is extremely narrow (usually on the order of several tens of micrometers) in order to achieve high-density recording. Therefore, the rotating cylinder 13 should be made to swivel as little as possible. is required. In general, experiments have shown that good recording and reproduction cannot be obtained unless the amount of wobbling is controlled to 10 μm or less.

In order to suppress whirling of the rotating part to a small extent, it is effective to have a sufficiently large bearing support force with respect to the weight and unbalanced weight of one rotating part. Therefore, in the device shown in FIG.
, 27' are provided. FIG. 14 shows the bearing housing 21 in detail. Each of the grooves forming the groove group 27 (or 27') opens vertically on the movement direction side (advancement side) with respect to the movement direction of the bearing housing 21 (the direction of arrow X in the figure), and goes rearward. It is composed of two grooves 27A, 27B that gradually become narrower as the width increases, and a groove 27G parallel to the 11111116 direction that connects the narrowest portions of these two grooves 27A, 27B. A plurality of grooves 27A, 27B, and 27G are arranged in parallel in the movement direction X, in other words, in the circumferential direction of the inner peripheral surface of the housing 21, forming a groove group 27 (or 27'). When a groove for generating dynamic pressure as shown in FIG. In the case of the example, air is used, but other gases or liquids such as lubricating oil may be used) in the groove portion 27A.

It is possible to cause the fluid to flow along the groove 27B to generate a dynamic pressure, and to hold the fluid that has flowed in by the groove 27G. That is, the groove group 27 has a pressure increasing function of increasing the bearing support load by the inclined groove parts 27A and 27B, and a pressure accumulating function of holding the increased pressure support load by the groove part 27C. We have realized an increase in the number of companies. This ``'υ'' shaped groove realizes a higher permissible bearing support load than the conventional ■groove.As a result, the whirling of the rotating cylinder 13 is extremely small, resulting in good records and
We have explained the width direction of the grooves above 0, which plays a major role in achieving regeneration, but this example also naturally applies to the first direction.
As shown in FIG. 2, it goes without saying that the groove depth is deeper toward the outside and shallower toward the inside. Furthermore, when the groove shown in Fig. 15 is used, the contact area between the shaft and the inner peripheral surface of the bearing housing is small, and the fluid retention performance is extremely high. There will be no problems caused by contact with.

In the embodiment shown in FIGS. 14 and 15 described above,
A groove group 27 for generating dynamic pressure is provided on the inner peripheral surface of the bearing housing 21.
27' is shown, however, the present invention should not be limited to this. In other words, it goes without saying that a group of grooves for generating dynamic pressure may be formed on the shaft. ·Also,
In the embodiments described above, the shaft is a stationary member and the bearing portion is a rotating member.

The present invention is not limited to this, and it goes without saying that the shaft may be a rotating member and the bearing portion may be a stationary member. Furthermore, even when the shaft is a rotating member, grooves for generating dynamic pressure may be formed on either the shaft surface or the bearing surface, and these should be considered to be within the scope of the idea of the present invention. It is.

Next, still another embodiment of the present invention will be described with reference to FIGS. 16 and 17. FIG. 16 shows the overall configuration of the embodiment device, and FIG. 17 shows a partially enlarged view of the shaft 16 in FIG. 16. In FIG. 16, the rotary cylinder 13 has the shaft 16 in its center. There is. Therefore, axis 1
6 rotates together with the one-rotation cylinder 13. The fixed cylinder 15 has a bearing housing 28 in its center, and the shaft 16 is inserted into a hole in the bearing housing 28 with a slight gap in which the shaft 16 can rotate.

The head 14 is installed in a rotary cylinder via the helad base 24, and the motor is composed of a rotor 18 and a stator 17. 1. A magnetic tape (not shown) is helically wound around the outer peripheral surfaces 25 and 26. The recording and reproduction of signals by the head 14 and the change in groove depth are the same as in the embodiment shown in FIG. In addition, in FIG. 16, the non-contact type signal transmission section is omitted from the drawing.

In the shaft 16 in FIG. 16, groove groups 29 and 29' for generating dynamic pressure are formed on the upper and lower sides. That is, the 17th IJ
! As shown in I, the groove has two inclined groove parts 29A and 29B.
(29A' and 29B'), and a pressure accumulating groove 29C (29C) that connects the narrowest part thereof.
29G').

The rotation of the shaft 16 due to the rotation of the 0-rotation cylinder 13, in which a group of grooves is formed by arranging a plurality of these grooves in parallel at a roughly equal pitch in the direction of rotational movement X, causes the inner peripheral surface of the shaft 16 and the bearing housing 28 to During this time, fluid supplied from the outside or existing therein flows along the pressure increasing grooves 29A and 29B of the dynamic pressure generating groove and is pressurized, and this pressurized fluid is held by the pressure accumulating groove 29C. This allows the whirling of the rotating cylinder 13 to be kept very small. Note that although the fluid used in this embodiment is air, it may be other gases or liquids such as lubricating oil. However, when using a liquid such as lubricating oil, consideration should be given to preventing liquid leakage and forming a passage for replenishing liquid from the outside to the bearing. Therefore, if lubricating oil is used, for example, the structure becomes somewhat complicated. Bearings having the groove shape shown in the above embodiments of the present invention always have a larger supported load value than conventional bearings. This is extremely useful in reducing the whirling of the rotating part as described above.

Note that the shape of the groove for generating dynamic pressure in the present invention is not limited to that described above, and for example, as shown in FIG. 18 and FIG. 19, two inclined groove portions 27A are used.

27B and the connecting groove 27G in the center may be somewhat rounded, or 27A.

Either 27B or 27G may be somewhat curved, and if such a roundness is provided, workability is improved when forming a groove by machining, and processing accuracy is also improved. Even if the entire groove is semicircular, elliptical, or other curved shape,
If the inclination angle of the groove increases toward the center, a higher allowable bearing support load can be obtained than in the case of the groove.

Regarding grooves for generating dynamic pressure in radial bearings, inclined groove 2
The groove widths of 7A and 27B and the groove width of the pressure accumulating groove part 27C are as follows:
The performance can be controlled by making a difference between the vibration amplitude of 27A or 27B and the groove width of 27C, which can be the same or different.

This allows it to be optimized for the device to which it is applied. Further, the grooves may be formed by a method such as etching cutting. For example, the parts other than those corresponding to the grooves are built up by welding, vapor deposition, etc.

A groove may be formed as a result; however, in the case of a groove-shaped thrust bearing, as mentioned above, the press forming method is the simplest and most desirable.

In the above description, grooves are used as a means for generating dynamic pressure, but the present invention is not limited thereto. Instead of the groove, a protrusion having a shape similar to that of each of the embodiments described above may be provided. In this case, the protrusion may be formed by any processing method. The protrusions still need to be sloped parts, and a connecting protrusion that connects them may also be used.

In this case, the rotation of the rotating member increases the pressure of the fluid along the inclined portion, and the pressure is maintained at the connecting protrusion. Therefore,
In the case of a protrusion, the same effect as in the case of a groove can be achieved, and the same effect can be achieved.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to realize a bearing device that can support a large bearing load and provide stable support.

Further, according to the present invention, it is possible to provide a thrust bearing in which the pumping action of the dynamic pressure generating groove is promoted, and a large supporting load capacity and axial flying height can be obtained. Therefore, the loss of torque on the sliding surface of the bearing is small, and the amount of wear is also significantly reduced.

In addition, since the hydrodynamic groove can be formed into a volume using a plastic working method, the processing time is shortened compared to the conventional photoetching method, the manufacturing cost is lower, and the productivity of the tray is significantly improved. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a thrust bearing according to an embodiment of the present invention, FIG. 2 is a front view of the thrust bearing of FIG. 1, and FIG. 3 is a schematic diagram showing the pressure distribution on the thrust bearing surface of FIG. 1. , FIG. 4, FIG. 5, and FIG. 6 are front views of thrust bearings according to other embodiments of the present invention. Figure 7 is a cross-sectional view including the mold showing the method for forming the thrust bearing in Figure 1, Figure 8 is a schematic cross-sectional view showing the mold surface pressure during bearing molding, and Figure 9 is a schematic diagram showing elastic deformation as well. Cross section, 1st
Figure 0 is a perspective view of a VTR using the thrust bearing of the present invention.
FIG. 11 is a sectional view of the VTR cylinder unit incorporated into the VTR shown in FIG. 10, FIG. 12 is a plan view of the bearing for defining the depth direction of the groove when the present invention is applied to a thrust bearing, and FIG. Bearing perspective views for defining the groove depth direction when similarly applied to a radial bearing, Figures 14 and 16
The figures are sectional views of other embodiments of the VTR cylinder unit incorporated in the VTR shown in Fig. 10, Fig. 15 is a partial sectional view of the vicinity of the radial bearing section applied to the device shown in Fig. 14, and Fig. 17 is the same as that shown in Fig. 16. A perspective view of a radial bearing applied to the device, and FIGS. 18 and 19 are schematic side views of a radial bearing according to other embodiments of the present invention, respectively. 1... Thrust bearing, 2... Dynamic pressure generating groove, 3...
Shaft, 4...Fluid film, 5...Mold, 7...Magnetic recording/reproducing device, 8...Cylinder, 9...Motor, 10...
...Upper cylinder, 11...Lower cylinder. 1. - Akira Fig. Fig. 2. Motion E generation groove series〉7' Rod No. Fig. Lareal + Or Moxibustion/IL Fig. Tomi Fig. Page 1'7 Fig. ■ /3 Fig. Fig.

Claims (1)

[Claims] 1. A bearing device in which a rotating member and a stationary member are disposed opposite to each other with a liquid film interposed therebetween, and a groove is formed on the opposing surface of the rotating member, wherein the groove is formed along a groove line. A bearing device characterized in that the bearing device is formed to be gradually deeper in the direction of rotation of the rotating member. 2. In a bearing device in which a rotating member and a stationary member are arranged facing each other with a liquid film interposed therebetween, and a groove is formed on the opposing surface of the stationary member, the groove is formed along a groove line and prevents rotation of the rotating member. A bearing device characterized in that it is formed gradually shallower in the direction. 3. The bearing device according to claim 1 or 2, wherein the groove has a smaller cross-sectional area at a shallower portion and a larger cross-sectional area at a deeper portion. 4. The bearing device according to claim 1, wherein the groove depth changes continuously. 5. The bearing device according to any one of claims 1 to 4, wherein the rotating member or the stationary member is a thrust bearing. 6. The bearing device according to claim 1, wherein the stationary member or the rotating member is a radial bearing. 7. In a thrust bearing in which a stationary member having a spiral groove on its sliding surface supports a rotating member disposed opposite the sliding surface of the stationary member in a floating manner via a fluid film, the spiral groove A thrust bearing characterized in that the depth of the groove is gradually shallowed along the length of the groove. 8. A thrust bearing in which a rotating member disposed opposite the sliding surface of the stationary member is floatingly supported via a fluid film by a stationary member having a spiral groove on the sliding surface, wherein the groove depth is A thrust bearing characterized in that the thrust bearing is shallow relative to the rotational direction of the rotating member. 9. The thrust bearing according to claim 7 or 8, wherein the groove is formed on the rotating member side instead of on the stationary member side, and the tendency of the groove depth is reversed. 10. A radial bearing comprising a stationary member and a rotating member according to any one of claims 7 to 9. 11. A groove for generating dynamic pressure is formed in at least one of the rotating member and a stationary member disposed opposite to the rotating member, and a fluid is interposed between the facing surfaces of the rotating member and the stationary member. , in a hydrodynamic bearing device that generates dynamic pressure by rotation of the rotating member and supports the rotating member, the groove is arranged such that the advancing side thereof is oriented with respect to the direction of relative movement between the rotating member and the stationary member. It consists of a pressure increasing groove that is open and narrows towards the rear, and a pressure accumulating groove that connects the narrower part of the pressure increasing grooves, and each groove has a length of the groove. A hydrodynamic bearing device characterized by varying depth in the direction. 12. The hydrodynamic bearing device according to claim 11,
A plurality of the grooves for generating dynamic pressure are formed in at least one of the rotating member or the stationary member in the relative movement direction, and the grooves are formed at substantially equal intervals. Dynamic pressure type hydrodynamic bearing device. 13. The hydrodynamic bearing device according to claim 11 or 12, wherein a plurality of grooves for generating dynamic pressure are formed in at least one of the rotating member or the stationary member in a direction perpendicular to the direction of relative motion. A hydrodynamic bearing device characterized by: 14. The hydrodynamic bearing device according to claim 11,
A hydrodynamic bearing device characterized in that the pressure accumulating groove portion is formed as a groove parallel to a rotating shaft. 15. The hydrodynamic bearing device according to claim 11,
The minimum pitch (2l_
The ratio between 1) and the maximum pitch (2l_2) is 0.3 to 0.
．． 8. A dynamic pressure type hydrodynamic bearing device characterized by being between 8 and 8. 16. The hydrodynamic bearing device according to claim 11,
A hydrodynamic bearing device characterized in that the fluid is a liquid. 17. The hydrodynamic bearing device according to claim 11,
A hydrodynamic bearing device characterized in that the fluid is gas. 18. Fitting the shaft member and the housing member, interposing a fluid between the facing surfaces of the shaft member and the receiving surface of the housing member, and at least either the shaft member or the receiving surface of the housing member. In a hydrodynamic bearing device in which a groove for generating dynamic pressure is formed on one side and a rotating member is supported by a relative rotational movement between the shaft member and the housing member, the groove for generating dynamic pressure is The groove includes two inclined groove parts that are open on the upstream side with respect to the direction of the fluid flow due to the relative rotational movement of the shaft member and the housing member, and that gradually become narrower toward the downstream side, and the two inclined groove parts. The movement is characterized in that the groove is configured with a groove portion communicating in a direction perpendicular to the relative rotational movement between the narrowest portions of the groove, and each groove has a depth that changes in the longitudinal direction of the groove. Pressure type hydrodynamic bearing device. 19. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the shaft member is the rotating member, and the groove for generating dynamic pressure is formed on a surface of the shaft member. 20. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the shaft member is the rotating member, and the groove for generating dynamic pressure is formed on a receiving surface of the housing member. 21. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the housing member is the rotation-side member, and the groove for generating dynamic pressure is formed in a receiving surface of the housing member. 22. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the housing member is the rotating member, and the groove for generating dynamic pressure is formed in the shaft member. 23. In the hydrodynamic bearing device according to any one of claims 18 to 22, a plurality of the grooves for generating dynamic pressure are formed in the direction of the relative rotational movement, and the pitch between them is approximately A hydrodynamic bearing device characterized in that the bearings are spaced at equal intervals. 24. The hydrodynamic bearing device according to any one of claims 18 to 23, wherein a plurality of sets of the grooves for generating dynamic pressure are formed in the direction of the rotation axis. 25. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that a ratio between a minimum value and a maximum value of the distance between the two inclined groove portions is between 0.3 and 0.8. 26. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the fluid is gas. 27. The hydrodynamic bearing device according to claim 18,
A hydrodynamic bearing device characterized in that the fluid is a liquid. 28. The hydrodynamic bearing device according to claim 18,
Dynamic pressure type fluid, wherein the groove for generating dynamic pressure is formed on a longitudinal end surface of the shaft member or on a receiving surface of the housing member opposite to the longitudinal end surface of the shaft member. Bearing device. 29. It has at least two opposing surfaces, these surfaces are arranged close to each other, a lubricating body is filled between these surfaces, and the lubricating body enters the gap between these surfaces due to the relative movement of these surfaces, In a hydrodynamic bearing device that generates pressure and uses this pressure to support opposing surfaces that move relative to each other in a non-contact state, at least one of the opposing surfaces that move relative to each other is provided with a A series of grooves or protrusions are provided, which are open on the advancing side and closed on the rear side, and whose angle from the direction of relative movement increases toward the rear, and the depth of the grooves or the height of the protrusions is What is claimed is: 1. A hydrodynamic bearing device of a hydrodynamic type, characterized in that a plurality of hydrodynamic bearings whose lengths change in the length direction are arranged side by side on surfaces facing relative motion. 30. The hydrodynamic bearing device according to claim 29,
The hydrodynamic bearing device is characterized in that the series of grooves or protrusions are formed in a plurality at substantially equal intervals in the relative motion direction. 31. The hydrodynamic bearing device according to claim 29 or 30, wherein the series of grooves or protrusions are formed in a plurality of sets in a direction orthogonal to the direction of relative motion. . 32. The hydrodynamic bearing device according to claim 29,
A hydrodynamic bearing device characterized in that a portion of the series of grooves or protrusions where the angle increases is orthogonal to the direction of relative motion. 33. The hydrodynamic bearing device according to claim 29,
The ratio of the length of the part where the angle increases in the series of grooves or protrusions to the distance between the parts on the furthest advancing side with respect to the relative movement direction is between 0.3 and 0.8. A hydrodynamic bearing device characterized by: 34. The hydrodynamic bearing device according to claim 29, wherein the lubricant is a liquid lubricant. 35. The hydrodynamic bearing device according to claim 29,
A hydrodynamic bearing device characterized in that the lubricating body is a gaseous lubricating body. 36. The hydrodynamic bearing device according to claim 29,
The hydrodynamic bearing device is characterized in that the portion of the series of grooves or protrusions where the angle increases includes a linear or curved portion substantially perpendicular to the direction of relative motion. 37. In a hydrodynamic bearing device having a rotating part and a fixed part supporting the rotating part, the rotating part with respect to the fixed part is inclined with respect to the rotation direction, and the upstream side with respect to the direction of fluid flow is Two inclined grooves or protrusions that are open and gradually narrow toward the downstream side are connected to a straight groove or protrusion perpendicular to the rotation direction, and the groove depth or the protrusion height is 1. A hydrodynamic bearing device comprising a bearing section in which each groove or projection varies in the length direction and a plurality of grooves or projections are arranged side by side on a surface facing relative motion. 38. The hydrodynamic bearing device according to claim 37,
The hydrodynamic bearing device is characterized in that the bearing portion is provided on a radial surface of the rotating portion. 39. The hydrodynamic bearing device according to claim 37,
The hydrodynamic bearing device is characterized in that the bearing portion is provided on a thrust surface of the rotating portion. 40. The hydrodynamic bearing device according to claim 27,
A hydrodynamic bearing device characterized in that a ratio between a minimum value and a maximum value of the distance between the two inclined grooves or the protrusions is from 0.3 to 0.8. 41. The hydrodynamic bearing device according to claim 27,
A hydrodynamic bearing device characterized in that the fluid is a liquid or gaseous lubricant. 42. A hydrodynamic bearing device having a rotating part having a magnetic head and a fixed part supporting the rotating part, and used in a device that performs magnetic recording and reproducing by winding a magnetic tape around the rotating part, wherein the rotating part Alternatively, a groove for generating dynamic pressure is formed on the surface of the fixed part facing the rotating part, and a fluid is interposed between the facing surfaces of the rotating part and the fixed part, so that the rotation of the rotating part causes movement. generating pressure to support the rotating part;
The groove for generating dynamic pressure includes two groove portions that are open on the advancing side and narrow toward the rear with respect to the direction of relative movement between the rotating portion and the fixed portion due to rotation of the rotating portion; What is claimed is: 1. A hydrodynamic bearing device comprising: grooves that communicate between narrowed portions of the grooves; and the depth of each groove varies along the groove line. 43. A mold having a convex portion in which the groove shape of the bearing groove according to each of claims 1 to 42 is transferred is attached to a substrate before processing that will become the groove forming surface of the stationary member or the rotating member. A method for producing a bearing member, characterized in that the bearing member is formed by pressing. 44. A method for manufacturing a bearing, characterized in that a groove of an arbitrary groove depth is formed by forming the mold according to claim 43 with materials having different longitudinal elastic modulus. 45. The bearing mold according to claim 44. 46. An apparatus comprising a rotating part having a magnetic head and a fixed part supporting the rotating part, and performing magnetic recording and reproducing by winding a magnetic tape around the rotating part, according to any one of claims 1 to 5 or claim 7. Applying the bearing described in any one of 41 to 41 as a thrust bearing, incorporating the thrust bearing into a rotating cylinder, arranging a shaft so that its end face faces the sliding surface of the thrust bearing, and placing the shaft on the end face of the shaft. A magnetic recording/reproducing device characterized in that a thrust bearing is floatingly supported via a liquid film. 47. A magnetic recording and reproducing device characterized in that the bearing device according to claim 42 is applied to the rotating part or the fixed part according to claim 42.