JP2002257132A - Dynamic pressure bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing by which a friction resistance against a rotary shaft is remarkably reduced due to further increased dynamic action and high speed rotation of the rotary shaft is realized. SOLUTION: A plurality of substantially V-shaped radial dynamic pressure groove 31 converging at the rotary direction (R direction) of the rotary shaft 4 is formed to make a herringbone pattern on the inter peripheral face 21 subjected to a radial load from the rotary shaft 4, and the convergence parts 32 of these radial dynamic grooves 41 are forced to deviate to one axial end side and further, the groove 31a of one end side among one and the other each groove 31a, 31b of the substantially V-shaped radial dynamic pressure groove 31 is made shorter than the opposite side groove 31b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing made of a sintered oil-impregnated bearing suitable for supporting a shaft rotating at a relatively high speed, such as a spindle motor bearing, with high precision.

[0002]

2. Description of the Related Art There is a technique for reducing sliding friction by providing a groove on an inner peripheral surface of a sliding bearing which receives a radial load and generating a dynamic pressure on an oil film formed between the bearing and a rotating shaft.
A plurality of grooves for generating dynamic pressure, that is, dynamic pressure grooves, are usually formed at intervals in the circumferential direction (rotational direction of the rotating shaft), and have a linear shape extending parallel to or oblique to the axial direction. , A triangular shape, and a substantially V-shaped herringbone pattern. Triangular or V
In the case of the U-shaped dynamic pressure grooves, the grooves are symmetrical with respect to the circumferential direction, and are formed in one or two rows along the circumferential direction. In addition, the depth of such a dynamic pressure groove may be uniform or may vary in the circumferential direction.

[0003] Further, in a bearing which receives a thrust load together with a radial load, a plurality of dynamic pressure grooves are formed radially or spirally on an end face which receives the thrust load, or a plurality of substantially V-shaped dynamic pressure grooves are provided. Is formed. Also in these dynamic pressure grooves, there are those having a uniform depth and those varying in the circumferential direction, and further, those having a bottom surface formed in a wavy shape in the circumferential direction and having an uneven depth. .

[0004] The dynamic pressure bearing in which the above-mentioned dynamic pressure grooves are formed is widely applied to sintered oil-impregnated bearings. In the case of a sintered oil-impregnated bearing, the formation of the dynamic pressure groove on the end face that receives the thrust load is performed by a punch of a mold at the time of molding the compact or sizing the sintered body. In addition, when the dynamic pressure grooves are formed on the inner peripheral surface, the dynamic pressure grooves are opened from the inner peripheral surface to the end face, and when the dynamic pressure grooves are parallel to the axial direction, when the green compact is molded or when the sintered body is formed. It is formed at the stage of sizing. In order to form a hydrodynamic groove that is not open to the end face but closed in the inner peripheral face, one end side is opened to the end face during molding of the green compact, and the sintered body is sized. Sometimes, a method of closing the open end is used. In addition, at the time of sizing, a convex portion formed on the outer peripheral surface of the core rod inserted into the shaft hole is stamped on the inner peripheral surface to form a dynamic pressure groove, and extraction of the core rod is performed by occurrence of spring back of the bearing. There is a way. The sintered oil impregnated with the dynamic pressure grooves formed in this way has a reduced frictional resistance with the rotating shaft due to the dynamic pressure action, and also functions for a long period of time. Particularly preferred.

[0005]

By the way, for example, a spindle motor of an optical disk device has a rotational speed of several thousands or more per minute, which is much higher than that of other rotary shafts. When a balance load is applied, the load moves in the circumferential direction, causing a runout. For this reason, in the dynamic pressure bearing that supports this, since an oil film is less likely to be formed between the bearing and the rotating shaft, frictional resistance increases, causing a problem that wear progresses faster and power consumption increases. . That is, the higher the speed of the optical disk device, the higher the performance of the dynamic pressure bearing is required.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a dynamic pressure bearing capable of coping with a high-speed rotation of a rotary shaft, in which the dynamic pressure action is further increased and the frictional resistance with the rotary shaft is greatly reduced.

[0007]

According to the present invention, a plurality of substantially V-shaped radial dynamic pressure grooves converging in the rotation direction of a rotating shaft are formed in a herringbone pattern on an inner peripheral surface receiving a radial load from the rotating shaft. The converging portion of the radial dynamic pressure groove is biased toward one end in the axial direction, and the groove on one end of one and the other grooves of the radial dynamic pressure groove having a substantially V shape is It is characterized by being formed shorter than the groove on the opposite side.

In the present invention, the case where the inner peripheral surface receiving the radial load from the rotating shaft is formed continuously over the entire area in the axial direction, and the case where two or more places are formed at intervals in the axial direction. including. When the inner peripheral surface extends over the entire area, the radial dynamic pressure grooves according to the present invention are basically formed in a single row in the circumferential direction over the entire area. The present invention includes a configuration in which the radial dynamic pressure groove is formed not at the entire area of the inner peripheral surface but at least at one end in the axial direction. In this case, the converging portion is biased toward one end in the axial direction as in the above configuration. The radial dynamic pressure grooves may be formed at both ends to form a total of two rows. Also, there is no radial dynamic pressure groove formed on the other end side, or a conventional radial dynamic pressure groove is formed, and different types of radial dynamic pressure grooves are formed at both ends in a row. Including.

On the other hand, when two or more inner peripheral surfaces receiving a radial load from the rotating shaft are formed at intervals in the axial direction, at least one of the inner peripheral surfaces formed on the axial end portion side. On the other hand, the radial dynamic pressure groove is formed. In this case, a radial dynamic pressure groove is formed in a single row in the entire axial direction of the inner peripheral surface, and the radial dynamic pressure groove of the present invention is similarly formed on the other inner peripheral surface. The other inner peripheral surface may not have a radial dynamic pressure groove formed therein, or may have a conventional radial dynamic pressure groove formed therein.

In the present invention including the above embodiments,
The radial dynamic pressure groove according to the present invention has a substantially V-shape that converges in the rotation direction of the rotating shaft, that is, the circumferential direction, and the converging portion is biased toward one end in the axial direction, and has a substantially V-shape. It is characterized in that one of the grooves of the dynamic pressure groove and the other of the other grooves are shorter than the groove on the opposite side. According to the present invention, the lubricating oil supplied to the radial dynamic pressure groove by the rotation of the rotating shaft converges to the converging portion while exerting the dynamic pressure action, and generates the highest hydraulic pressure in the converging portion. Since the converging portion is biased toward one end, for example, when two hydrodynamic bearings of the present invention are arranged and combined so that the converging portions are located on the end portions, the distance between the converging portions with high hydraulic pressure is reduced. become longer. For this reason, the dynamic pressure action is further increased, the rigidity for suppressing the run-out and fall of the rotary shaft is improved, and the frictional resistance with the rotary shaft is greatly reduced. As a result, it can be used as a bearing for a rotating shaft of a high-speed rotation specification.

In order to obtain the above-mentioned effects more effectively,
It is preferable that the converging portion of the radial dynamic pressure groove is disposed at one end as much as possible. Further, the end of the shorter groove extending from the converging portion of the radial dynamic pressure groove to one end may be closed on the inner peripheral surface, but is opened to the chamfer formed on the end surface or the edge of the shaft hole. It may be in a form. In this case, the lubricating oil accumulated between the rotating shaft and the end portion is conveyed to the converging portion, and the leakage of the lubricating oil due to the rotation of the rotating shaft is suppressed.

The shape of the V-shaped radial dynamic pressure groove may be such that each V-shaped groove is linear or curved. In addition, the depth of the radial dynamic pressure groove should be increased in the rotational direction of the rotating shaft in order to expect the dam effect of the lubricating oil, or conversely, in order to improve the wedge effect of the lubricating oil, It can be made shallower toward.

Next, the present invention relates to a dynamic pressure bearing which receives a thrust load as well as a radial load from a rotary shaft. A plurality of extending thrust dynamic pressure grooves are formed substantially radially, and a plurality of substantially V-shaped radial dynamic pressure grooves converging in the rotation direction of the rotating shaft are formed in a herringbone pattern on an inner peripheral surface receiving a radial load. It is characterized by being formed.

In the present invention, further, the converging portion of the radial dynamic pressure groove is biased toward the end face side where the thrust dynamic pressure groove is formed, and one and the other of the substantially V-shaped radial dynamic pressure grooves are formed. The groove on the end face side of the groove on which the thrust dynamic pressure groove is formed is shorter than the groove on the opposite side.

[0015] In these inventions, similarly to the above invention, the inner peripheral surface receiving a radial load from the rotating shaft is formed continuously over the entire area in the axial direction, and at two places at intervals in the axial direction. The above case is also included. When the inner peripheral surface extends over the entire area, the radial dynamic pressure grooves according to the present invention are basically formed in a single row in the circumferential direction over the entire area. The present invention includes a configuration in which the radial dynamic pressure groove is formed not at the entire area of the inner peripheral surface but at least at one end in the axial direction. In this case, the converging portion is biased toward one end in the axial direction as in the above configuration. The radial dynamic pressure grooves may be formed at both ends to form a total of two rows. Also, there is no radial dynamic pressure groove formed on the other end side, or a conventional radial dynamic pressure groove is formed, and different types of radial dynamic pressure grooves are formed at both ends in a row. Including.

On the other hand, when two or more inner peripheral surfaces receiving a radial load from the rotating shaft are formed at intervals in the axial direction, the radial dynamic pressure is formed at the end on the side where the thrust dynamic pressure groove is formed. It is characterized in that a groove is formed. In this case, a radial dynamic pressure groove is formed in a row in the entire axial direction of the inner peripheral surface, and the radial dynamic pressure groove of the present invention is similarly formed on the inner peripheral surface at the opposite end. Including the form that has been. Further, no radial dynamic pressure groove may be formed on the inner peripheral surface at the opposite end, or a conventional radial dynamic pressure groove may be formed.

The thrust dynamic pressure groove has a shape which can be easily arranged according to the area of the end face to be formed.
Shapes such as an elliptical shape, a triangular shape, and a streamline shape are applied. Further, the thrust dynamic pressure groove may have either an inner peripheral end closed in the end face or an open end in a chamfer formed in the inner peripheral face or the edge of the shaft hole. Furthermore, the end on the outer peripheral side of the thrust dynamic pressure groove may be either closed in the end face or open to the outer peripheral side.

In such a thrust dynamic pressure groove, lubricating oil is supplied by the rotation shaft sliding on the end face, and the friction is reduced by the dynamic pressure action. The thrust dynamic pressure grooves extend from the outer peripheral side to the inner peripheral side as going in the rotation direction of the rotating shaft, and since these are arranged in a substantially radial manner,
The supplied lubricating oil positively flows toward the inner peripheral side by the rotation of the rotating shaft. As a result, the leakage of the lubricating oil to the outer peripheral side is suppressed, and the hydraulic pressure on the inner peripheral side is increased to promote the supply of the lubricating oil to the end of the inner peripheral surface, thereby reducing the friction of the inner peripheral surface. . It is preferable that the end on the outer peripheral side of the thrust dynamic pressure groove is closed in the end face, because leakage of lubricating oil due to centrifugal force can be further suppressed.

When a form in which the inner peripheral end of the thrust dynamic pressure groove is closed is applied to the sintered oil-impregnated bearing, the lubricating oil permeates into the pores from a high oil pressure portion to the inner peripheral surface or the end surface. And circulate. On the other hand, in the case where the inner peripheral end of the thrust dynamic pressure groove is open to the inner peripheral surface or the chamfer formed at the edge of the shaft hole, the lubricating oil is V-shaped on the inner peripheral surface. It is possible to flow into the groove on the end side of the radial dynamic pressure groove,
The oil pressure in the groove and the converging portion increases. When the length of the groove portion on the end portion side of the radial dynamic pressure groove is formed shorter than the groove portion on the opposite side, the effect can be obtained remarkably.

In the present invention, by arranging the converging portion of the radial dynamic pressure groove as close to the end as possible in the same manner as in the previous invention,
The convergence portion and the thrust dynamic pressure groove are close to each other, and the hydraulic pressure in the portion between the two is increased, and buoyancy is applied to the rotating shaft, thereby reducing friction. Also, if radial dynamic pressure grooves are formed at both ends of the inner peripheral surface, the distance of the high oil pressure part is increased as described above, so that the rigidity for suppressing the runout and falling of the rotary shaft is improved, and Frictional resistance is greatly reduced. The short groove portion on the end side of the radial dynamic pressure groove may be closed on the inner peripheral surface, but if it is open to the end surface, the flowability of the lubricating oil in the thrust dynamic pressure groove becomes good, and the dynamic pressure action Is more remarkably obtained.

When it is desired to improve the flowability of the lubricating oil between the radial dynamic pressure groove and the thrust dynamic pressure groove, the opposite ends of the two grooves may be directly communicated with each other, or each end may be connected to the edge of the shaft hole. What is necessary is just to open to the formed chamfer. Also,
In the case of a sintered oil-impregnated bearing, if it is desired to obtain a lubricating oil circulating effect using pores with relatively low flowability, both hydrodynamic grooves are closed and the opposite ends are staggered. do it.

The hydrodynamic bearing according to the present invention is suitably applied to a sintered oil-impregnated bearing that is porous and impregnated with lubricating oil. In the sintered oil-impregnated bearing, the lubricating oil is supplied and sucked and circulated to the sliding surface with the rotating shaft, that is, the inner peripheral surface receiving the radial load and the end surface receiving the thrust load, by the lubricating oil flowing through the pores. I do. The present invention enables the circulation of the lubricating oil and the generation of the dynamic pressure of the lubricating oil to be more effectively generated, thereby making it possible to extend the service life associated with the reduction of friction and to cope with high-speed specifications.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. 8 to 11 show the structure of a general bearing. In a bearing 1A shown in FIG. 8, a cylindrical sintered oil-impregnated bearing body 3 is press-fitted into a cylindrical metal housing 2, and supports a rotating shaft 4 inserted into the bearing body 3. In a bearing 1B shown in FIG. 9, two bearing bodies 3 press-fitted into a housing 2 are arranged at both ends of the housing 2 at an interval from each other, and a rotating shaft 4 is supported by both bearing bodies 3. A bearing 1C shown in FIG.
Is press-fitted, and the rotating shaft 4 supported by the bearing body 3 has a disk-shaped flange 4 a, and the flange 4 a slides on one end surface of the bearing body 3. Bearing 1 shown in FIG.
D is suitable for a spindle motor bearing. Two bearings 3 are press-fitted into a bottomed cylindrical housing 2 at an interval, and the tip of a spherically-shaped rotating shaft 4 is attached to the bottom of the housing 2. And the flange 4a slides on the end face of the bearing body 3 on the opening side to prevent leakage of lubricating oil. Below, these bearings 1A-1D
An embodiment of the bearing body according to the present invention applied to the present invention will be described.

(1) First Embodiment The bearing 11 shown in FIG. 1A is cylindrical, and the inner peripheral surface 21 receives a radial load from a rotating shaft. Inner peripheral chamfers 22 are formed at both end edges of the shaft hole of the bearing body 11, and outer peripheral chamfers 23 are formed at outer peripheral edges at both ends. A plurality of radial dynamic pressure grooves 31 are formed on the inner peripheral surface 21 at equal intervals in the circumferential direction over the entire circumference. These radial dynamic pressure grooves 31 have a substantially V-shape that converges in the rotation direction of the rotation shaft indicated by the arrow R, and have a herringbone pattern as a whole. The radial dynamic pressure groove 31 is formed over the entire length of the inner peripheral surface 21, and both ends thereof are open to the inner peripheral chamfered portion 22. Radial dynamic pressure groove 31 in this case
The convergence portion 32, which is the vertex, is biased toward one end in the axial direction (the upper end in FIG. 1A), thereby forming a V-shaped 2.
The length of the groove 31a at one end of the converging portion 32 of the two grooves 31a and 31b is shorter than the length of the other groove 31b. In the illustrated example, the radial dynamic pressure groove 31 is linear, but may be formed in a curved shape that is curved outward or inward.

The bearing body 11 of FIG. 1B is a modification of FIG. 1A, in which the radial dynamic pressure groove 31 is not formed over the entire length, but is formed to be biased toward one end. In this case, the long groove portion 31b extends only slightly from the axial middle portion to the other end (the lower end in FIG. 1B), and the inner peripheral surface 21 from the tip to the other end is a smooth cylindrical surface. is there. Also,
The short groove portion 31a is not open to the inner peripheral chamfered portion 22, so that the radial dynamic pressure groove 31 is closed on the inner peripheral surface 21.

The bearing body 11 of the first embodiment is shown in FIG.
1B, and a modified example as shown in FIG. 1B can be considered. As another modified example, both ends of the radial dynamic pressure groove 31 of FIG. 1A are not opened to the inner peripheral chamfered portion 22 but are closed at the inner peripheral surface 21, and FIG.
The radial dynamic pressure groove 31 shown in FIG.
(B) at the lower end).
Further, the radial dynamic pressure groove 31 may be formed on one end side, and a conventionally known radial dynamic pressure groove not related to the present invention may be formed on the other end side.

The bearing body 11 according to the first embodiment is
It is applied as the bearing body 3 of the bearings 1A and 1B shown in FIG. 8 or FIG. FIG. 2 shows an example applied to the bearing 1B of FIG. In this case, the two bearing bodies 11 are press-fitted into the ends of the housing 2 at intervals.
The converging portion 32 of the radial dynamic pressure groove 31 of each bearing body 11 converges in the rotation direction (the direction of arrow R) of the rotating shaft (not shown),
In addition, the converging portions 32 are each biased toward the end. In this case, both ends of the radial dynamic pressure groove 31 are not open to the inner peripheral chamfered portion 22 but are closed on the inner peripheral surface 21. According to such a bearing 11A, the two bearing bodies 1
Since the converging portion 32 of the radial dynamic pressure groove 31 is biased toward the end, the distance between the converging portions 32 with high hydraulic pressure becomes longer,
In other words, 2 which mainly supports the rotating shaft by the dynamic pressure action
The distance between points can be increased. For this reason, the dynamic pressure action is further increased, the rigidity for suppressing the run-out and fall of the rotary shaft is improved, and the frictional resistance with the rotary shaft is greatly reduced. Further, the lubricating oil flowing out to the end face is caused to flow to the converging portion 32 through the groove 31a on the end side of the radial dynamic pressure groove 31, thereby suppressing leakage of the lubricating oil to the end face side due to rotation of the rotating shaft.

When the bearing body 11 is applied to the bearing 1A shown in FIG. 8, the radial dynamic pressure grooves 31 are formed at both ends, or the radial dynamic pressure grooves 31 are formed at one end and the other end is formed. In this case, a conventionally known form in which a radial dynamic pressure groove is formed is applied. In this application example, the distance between the high oil pressure portions on both ends of one bearing body 11 is smaller than that of the conventional one because the converging portion 32 of the radial dynamic pressure groove 31 according to the present invention is formed on the end side. Is also longer. Therefore,
As described above, the rigidity for suppressing the run-out and fall of the rotary shaft is improved, and the frictional resistance with the rotary shaft is greatly reduced.

(2) Second Embodiment Next, an embodiment of a bearing which receives a radial load on the inner peripheral surface and a thrust load on one end surface will be described. A plurality of radial dynamic pressure grooves 31 are formed at equal intervals in the circumferential direction on the inner peripheral surface 21 of the bearing body 12 shown in FIG. These radial dynamic pressure grooves 31 have a substantially V-shape converging in the direction of rotation of a rotating shaft (not shown) indicated by an arrow R, and have a herringbone pattern as a whole. The radial dynamic pressure groove 31 is formed over the entire length of the inner peripheral surface 21, and both ends thereof are open to the inner peripheral chamfered portion 22. In this case, the converging portion 32 of the radial dynamic pressure groove 31 is located at an intermediate portion in the axial direction, and the radial dynamic pressure groove 31 is formed symmetrically with respect to the circumferential direction.

On the other hand, a plurality of thrust dynamic pressure grooves 35 are provided on the end face 24 on one end side (upper end side in FIG. 3A) of the bearing body 12.
Are radially formed at equal intervals in the circumferential direction.
As shown in FIG. 4A, the thrust dynamic pressure grooves 35 extend while slightly bending from the outer peripheral side to the inner peripheral side in the rotation direction R of the rotating shaft. The thrust dynamic pressure groove 35 in the case of FIG. 4A is closed in the end face 24, but as shown in FIG. 4B, the end on the inner circumferential side is the inner circumferential face 21 (or the inner circumferential chamfered portion). 22)
Further, the outer peripheral side end may be open to the outer peripheral surface 25 (or the outer peripheral chamfered portion 23). FIG.
The outer peripheral end of the thrust dynamic pressure groove 35 in FIG.
4, the inner peripheral end is open to the inner peripheral chamfer 22, and the thrust dynamic pressure groove 35 communicates with the radial dynamic pressure groove 31 via the inner peripheral chamfer 22. .

The bearing body 12 shown in FIGS. 3B and 3C is a modification of the second embodiment. In the bearing body 12 of FIG. 3B, the converging portion 32 of the radial dynamic pressure groove 31 is biased toward one end (the upper end in FIG. 3B) as shown in FIG. , Two V-shaped grooves 31
The length of the groove 31a on the end face 24 side where the thrust dynamic pressure groove 35 is formed is shorter than the other groove 31b. The bearing body 12 shown in FIG.
3B, the radial dynamic pressure groove 31 is biased toward one end (the upper end in FIG. 3C) where the thrust dynamic pressure groove 35 is formed, and the thrust dynamic pressure groove 35 is an inner peripheral chamfer. It is in communication with the radial dynamic pressure groove 31 via 22.

The bearing body 12 according to the second embodiment is
It is applied as the bearing body 3 of the bearings 1C and 1D shown in FIG. 10 or FIG. FIG. 5 shows an example in which the bearing body 12 shown in FIG. 3C is applied to the bearing 1C of FIG.
In this bearing 12A, a flange of a rotating shaft (not shown) inserted into the bearing body 12 slides on the end face 24 on which the thrust dynamic pressure groove 35 is formed, whereby lubricating oil is supplied to the thrust dynamic pressure groove 35. As a result, a dynamic pressure action occurs, and friction is reduced. The thrust dynamic pressure grooves 35 extend from the outer peripheral side to the inner peripheral side in the direction of rotation of the rotating shaft indicated by the arrow R. Since these are arranged in a substantially radial manner, the supplied lubricating oil is rotated by the rotating shaft. With the rotation of, it flows positively toward the inner circumference. As a result, the leakage of the lubricating oil to the outer peripheral side is suppressed, and the hydraulic pressure on the inner peripheral side is increased to increase the inner peripheral surface 2.
The supply of the lubricating oil to the end portion 1 is promoted, and the friction of the inner peripheral surface 21 is reduced. In particular, the converging portion 3 of the radial dynamic pressure groove 31
2 is biased toward the end where the thrust dynamic pressure groove 35 is formed, and since the thrust dynamic pressure groove 35 communicates with the radial dynamic pressure groove 31 via the inner peripheral chamfered portion 22, the thrust dynamic pressure The hydraulic pressure on the inner peripheral surface at the end of the shaft hole extending from the end face where the groove 35 is formed to the radial dynamic pressure groove 31 is likely to be increased, and the sliding characteristics on the radial side are further improved.

FIG. 6A shows the bearing 1 shown in FIG.
FIG. 6B shows an example in which No. 2 is applied to the bearing 1D of FIG.
Shows an example in which the bearing body 12 shown in FIG. 3B is applied to the bearing 1D of FIG. The bearing 12B of FIG.
The bearing body 12 shown in FIG. 3A is press-fitted into one end of the housing 2 (the upper end in FIG. 6A), and the other end is provided with the bearing body 12 shown in FIG. , A general bearing body 5 in which the thrust dynamic pressure groove 35 is not formed on the end face 24
Are press-fitted and arranged. In this example, as the bearing body 12 having the thrust dynamic pressure groove 35, the bearing body 12 shown in FIG. 3B or 3C may be applied. Further, as the bearing body 5 having no thrust dynamic pressure groove 35 on the other end side, the bearing body 11 shown in FIG. 1A or FIG.
May be applied.

In the bearing 12C of FIG. 6B, the bearing body 12 having the thrust dynamic pressure groove 35 is press-fitted into one end (the upper end in FIG. 6B) of the housing 2, and is arranged at the other end. Is
A cylindrical bearing body 6 having a smooth inner peripheral surface 21 on which neither the radial dynamic pressure groove 31 nor the thrust dynamic pressure groove 35 is formed is press-fitted. Bearing body 1 having thrust dynamic pressure groove 35
Reference numeral 2 denotes a modified example of the bearing body 12 shown in FIG. 3B, and the inner side of the radial dynamic pressure groove 31 (the lower end side in FIG. 6B).
Is not open to the inner peripheral chamfered portion 22, and the inner peripheral surface 2
Closed at 1.

The bearings 12A, 12 shown in FIGS.
Also in 2C, due to a synergistic effect of the thrust dynamic pressure groove 35 and the radial dynamic pressure groove 31, the end face 24 on which the thrust dynamic pressure groove 35 is formed and the dynamic pressure action by the rotation of the rotating shaft is formed.
Can be obtained in the same manner as in the bearing 12A.

(3) Third Embodiment Next, a third embodiment according to the present invention will be described with reference to FIG. The bearing body 13 shown in FIG. 7 has inner peripheral surfaces 21 that receive a radial load from a rotating shaft rotating in the direction of arrow R formed at both axial ends, and an inner peripheral surface 21 between these inner peripheral surfaces 21. A middle escape portion 41 having a larger diameter than the rotary shaft does not contact is formed. The outer diameter corresponding to the lower inner peripheral surface 21 in FIG. 7 is smaller than the other parts, and this bearing body 13 has a small diameter part 42 and a large diameter part 43. The middle escape part 41 is
The outer circumference of the portion corresponding to the small diameter portion 42 of the bearing material, in which the outer diameter is uniform and the inner diameter of the portion corresponding to the small diameter portion 42 is the same as the middle relief portion 41, is reduced in diameter by a mold. And can be formed. A radial dynamic pressure groove 31 similar to that shown in FIG. 2 is formed on the two inner peripheral surfaces 21 of the bearing body 13. Also, the end face 2 on the large diameter portion 43 side
4 includes a thrust dynamic pressure groove 3 which is open to the inner peripheral chamfered portion 22.
5 are formed.

The bearing body 13 of the third embodiment is, for example, shown in FIG.
This is applied to the bearing 1C shown in FIG. 0, in which case the flange of the rotary shaft slides on the end face 24 on the large diameter portion 43 side where the thrust dynamic pressure groove 35 is formed. According to the bearing body 13, since the converging portions 32 of the radial dynamic pressure grooves 31 are biased toward both ends of the inner peripheral surface 21, the distance between two points that mainly support the rotating shaft by dynamic pressure action. Become longer,
The dynamic pressure action is further enhanced, the rigidity for suppressing the runout and fall of the rotary shaft is improved, and the frictional resistance with the rotary shaft is greatly reduced. Further, the synergistic effect of the thrust dynamic pressure groove 35 and the radial dynamic pressure groove 31 reduces the dynamic pressure effect due to the rotation of the rotating shaft and the lubricating oil leakage suppressing effect on the end face 24 where the thrust dynamic pressure groove 35 is formed. It can be obtained in the same manner as in the second embodiment. Furthermore, the inner peripheral surface 21 on the small diameter portion 42 side
In this case, the lubricating oil accumulated near the inner peripheral chamfered portion 22 is sucked into the short groove portion 31a of the radial dynamic pressure groove 31, so that the scattering of the lubricating oil is suppressed and the dynamic pressure effect can be obtained effectively. .

The bearing 13 is also suitably used as the spindle motor bearing 1D shown in FIG. In this case, the oil pressure near the converging portion 32 of the radial dynamic pressure groove 31 at both ends becomes highest due to the rotation of the rotating shaft. Since the radial dynamic pressure groove 31 is formed over the entire circumference of the inner peripheral surface 21 that receives the radial load, even if the rotating shaft oscillates, the lubricating oil is constantly and uniformly supplied to the inner peripheral surface 21. The rotating shaft can rotate smoothly while the dynamic pressure action always occurs. When the rotating shaft rotates, a dynamic pressure action is generated by the thrust dynamic pressure groove 35 on the end surface 24 on which the flange slides, and smooth sliding is performed even when a thrust load is received, and the lubricating oil is moved in the radial dynamic pressure groove. 3
1 and the hydraulic pressure in the radial dynamic pressure groove 31 of the inner peripheral surface 21 is further increased. On the other hand, when lubricating oil is present in the space between the thrust receiving plate and the bearing body on the inner peripheral surface 21 on the small diameter portion 42 side, the lubricating oil is sucked into the inner peripheral surface 21 by the radial dynamic pressure groove 31, This effectively produces a dynamic pressure effect.

[0039]

As described above, according to the dynamic pressure bearing of the present invention, the dynamic pressure groove in which the dynamic pressure action is further enhanced and the frictional resistance with the rotating shaft is greatly reduced is effectively formed. So
It is very promising as a dynamic pressure bearing that can cope with high-speed rotation of a rotating shaft.

[Brief description of the drawings]

FIGS. 1A and 1B are longitudinal sectional views of a bearing body according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the bearing according to the first embodiment of the present invention.

FIGS. 3 (a), (b) and (c) are longitudinal sectional views of a bearing body according to a second embodiment of the present invention.

FIG. 4 is a top view of a bearing body showing a thrust dynamic pressure groove according to the present invention.

FIG. 5 is a sectional view of a bearing according to a second embodiment of the present invention.

FIGS. 6A and 6B are cross-sectional views of another type of bearing according to the second embodiment of the present invention.

FIG. 7 is a sectional view of a bearing according to a third embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a structural example of a general bearing.

FIG. 9 is a vertical sectional view showing another example of the structure of a general bearing.

FIG. 10 is a longitudinal sectional view showing another example of a general bearing structure.

FIG. 11 is a vertical sectional view showing another example of the structure of a general bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 4 ... Rotating shaft 11, 12, 13 ... Bearing body 11A, 12A, 12B, 12C ... Bearing 21 ... Inner peripheral surface 22 ... Inner peripheral chamfered part 31 ... Radial dynamic pressure groove 31a, 31b ... Groove part 32 ... Convergent part 35 ... Thrust Dynamic pressure groove

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3J011 AA10 AA11 AA12 BA02 BA08 CA03 JA02 KA02 KA03 LA01 MA03 5H605 BB05 BB14 CC04 DD03 EA06 EB06 EB17 GG09 GG14 5H607 BB01 BB14 BB25 CC01 DD03 DD16 GG01 GG09 GG09

Claims (10)

[Claims] A plurality of substantially V-shaped radial dynamic pressure grooves converging in the rotation direction of the rotation shaft are formed in a herringbone pattern on an inner peripheral surface receiving a radial load from the rotation shaft. The converging portion is biased toward one end in the axial direction, and the groove on one end of one and the other of the radial dynamic pressure grooves forming a substantially V shape is formed shorter than the groove on the opposite side. A dynamic pressure bearing characterized by being made. 2. A plurality of substantially V-shaped radial dynamic pressure grooves converging in the rotation direction of the rotating shaft are formed in a herringbone pattern on at least one axial end of an inner peripheral surface receiving a radial load from the rotating shaft, A dynamic pressure bearing, wherein the groove on one end of one and the other of the substantially dynamic V-shaped radial dynamic pressure grooves is formed shorter than the groove on the opposite side. 3. A hydrodynamic bearing in which two or more inner peripheral surfaces receiving a radial load from a rotating shaft are formed at intervals in an axial direction, and each inner peripheral surface formed on an axial end portion side. A plurality of substantially V-shaped radial dynamic pressure grooves are formed in a herringbone pattern on at least one of the surfaces, the plurality of substantially dynamic V-shaped grooves being converged in the direction of rotation of the rotation shaft, and the converged portion is biased toward the outer end side. A dynamic pressure bearing, wherein a groove on the outer end side of one and the other of the radial dynamic pressure grooves having a letter shape is formed shorter than a groove on the opposite side. 4. A plurality of thrust dynamic pressure grooves which extend from the outer peripheral side to the inner peripheral side as going in the rotation direction of the rotary shaft are formed substantially radially on one end face which receives a thrust load from the rotary shaft. A plurality of substantially Vs converging in the rotation direction of the rotating shaft are provided on an inner peripheral surface receiving a radial load from the rotating shaft.
A hydrodynamic bearing in which a U-shaped radial dynamic pressure groove is formed in a herringbone pattern. 5. A plurality of thrust dynamic pressure grooves extending radially from an outer peripheral side to an inner peripheral side in a rotation direction of the rotating shaft are formed on one end face of the rotating shaft, which receives a thrust load from the rotating shaft. A plurality of substantially Vs converging in the rotation direction of the rotating shaft are provided on an inner peripheral surface receiving a radial load from the rotating shaft.
A radial dynamic pressure groove having a V-shape is formed in a herringbone pattern, and a converging portion of the radial dynamic pressure groove is biased toward the end face side where the thrust dynamic pressure groove is formed, and has a substantially V shape. A dynamic pressure bearing, wherein a groove on the end face side of the radial dynamic pressure groove on which the thrust dynamic pressure groove is formed is shorter than a groove on the opposite side. 6. A plurality of thrust dynamic pressure grooves extending radially from an outer peripheral side toward an inner peripheral side in a direction of rotation of the rotary shaft are formed on one end face of the rotary shaft receiving a thrust load from the rotary shaft. A plurality of substantially V-shaped radial dynamic pressure grooves converging in the direction of rotation of the rotary shaft are herringbone at least at the end of the inner peripheral surface receiving the radial load from the rotary shaft on the end face side where the thrust dynamic pressure grooves are formed. Further, the converging portion of the radial dynamic pressure groove formed on the end face side where the thrust dynamic pressure groove is formed is biased toward the end face side where the thrust dynamic pressure groove is formed, and substantially V The dynamic pressure is characterized in that, of the radial dynamic pressure grooves having a U-shape, the groove on the end face side where the thrust dynamic pressure groove is formed is shorter than the groove on the opposite side. bearing. 7. A hydrodynamic bearing in which two or more inner peripheral surfaces receiving a radial load from a rotating shaft are formed at intervals in an axial direction, wherein the inner peripheral surface is formed at an axial end. A plurality of thrust dynamic pressure grooves extending from the outer peripheral side to the inner peripheral side as going in the rotation direction of the rotating shaft are formed in a substantially radial shape on the end face continuous with, and at least the thrust dynamic pressure grooves on the inner peripheral face are A plurality of substantially V-shaped radial dynamic pressure grooves converging in the rotating direction of the rotating shaft are formed in a herringbone pattern at an end on the formed side, and further formed on an end face side where the thrust dynamic pressure grooves are formed. The converging portion of the formed radial dynamic pressure groove is biased toward the end face side where the thrust dynamic pressure groove is formed, and the thrust motion of one and the other of the substantially V-shaped radial dynamic pressure grooves is changed. The groove on the end face side where the pressure groove is formed A dynamic pressure bearing characterized by being formed shorter than the groove. 8. An inner peripheral end of the thrust dynamic pressure groove and an end of the radial dynamic pressure groove on an end face side where the thrust dynamic pressure groove is formed, directly or at an edge of a shaft hole. The dynamic pressure bearing according to any one of claims 4 to 7, wherein the dynamic pressure bearing communicates via a formed chamfer. 9. An inner peripheral end portion of the thrust dynamic pressure groove and an end portion of the radial dynamic pressure groove on an end face side where the thrust dynamic pressure groove is formed are correspondingly close to each other. The dynamic pressure bearing according to any one of claims 4 to 8, wherein: 10. The dynamic pressure bearing according to claim 1, which is a sintered oil-impregnated bearing.