JP2002323039A - Manufacturing method of oscillating bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive small-sized oscillating bearing 8 of high performance. SOLUTION: For manufacturing an outer ring 15, two pieces of steel materials are firstly forged for forming first and second outer ring elements 18, 19 that constitute the outer ring 15, or steel powder is sintered to form ring materials so that the whole of each elements is formed into an arc shape. The first and second outer ring elements 18, 19 are manufactured such that a plurality of fixing grooves 21a, 21b are formed at internal peripheries of the elements by grinding the internal peripheries of the ring materials, and coupled with each other to form the outer ring 15. A plurality of balls 17, 17, of which the surfaces are nitrided, are incorporated between the fixing grooves 21a, 21b of the internal periphery of the outer ring 15 formed as above and a partial spherical part 14 formed at the external periphery of an inner ring 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of manufacturing a rocking bearing, in which a mounting object such as a sample or a workpiece mounted on an upper surface of a moving table is moved to a predetermined position in space with respect to a fixed table. The present invention also relates to a method of manufacturing a rocking bearing incorporated in a rocking support portion such as a parallel link mechanism used for tilting the mounted object in a predetermined direction.

[0002]

2. Description of the Related Art Conventionally, a moving device for moving a mounted object such as a sample or a workpiece from a predetermined position to another predetermined position in a space and tilting the mounted object in a predetermined direction has been conventionally used. For example, a structure as shown in FIG. 5 is used. The moving device 1 includes a fixed base 2, a moving base 3 provided above the fixed base 2, and a plurality of moving bases 3 provided between the fixed base 2 and the moving base 3, each constituting a parallel link mechanism. (Six in the illustrated example). Each of these legs 9, 9 comprises a first and second link element 5, 6 arranged in series with each other, and a telescopic mechanism 7, 7 provided at a portion between these first and second link elements 5, 6. And Then, a portion between the plurality of corner portions of the movable base 3 and the upper end of each of the first link elements 5 and 5, and a plurality of corner portions of the fixed base 2 and each of the second link elements 6 ,
The swing bearings 8 and 8 are provided in a portion between the lower end portion 6 and the lower end portion 6.

[0003] Each of the telescoping mechanisms 7 and 7 includes, for example, as shown in the figure, pistons 10 and 10 fixedly coupled to the lower ends of the first link elements 5 and 5, respectively, and the second link elements 6 and 6 which are connected and fixed to the upper end of the cylinder 6. The inside of each of the cylinders 11 is connected to a supply / discharge device (not shown), and a working fluid such as compressed air is supplied / discharged into / from each of the cylinders 11 from the supply / discharge device. The entire length of 9, 9 is made to expand and contract. Each cylinder 11 by the above-mentioned supply and discharge device,
The supply and discharge of the working fluid into and from the inside 11 are controlled by a controller (not shown). Further, each of the rocking bearings 8, 8 is provided at a plurality of corners of the movable table 3 or the fixed table 2, at an end of each of the first link elements 5, 5 or each of the second link elements 6, 6. , The swing displacement is freely supported.

When the moving device 1 is used as described above, the working fluid is supplied and discharged into and from the cylinders 11 by the supply and discharge device. Due to such supply and discharge of the working fluid, the entire length of each of the legs 9, 9 expands or contracts by a predetermined length, and accordingly, the inclination angle and height of the movable table 3 with respect to the fixed table 2 are increased. Changes. Therefore, when the object 12 such as a sample is placed on the upper surface of the moving table 3, the object 12 is moved from a predetermined position to another predetermined position in the space, and the object 12 is oriented in a predetermined direction. The tilted state or the tilted object 12 can be horizontal.

Conventionally, as the oscillating bearings 8 constituting the moving device 1 as described above, a spherical portion and a partial spherical portion provided outside the spherical portion and capable of sliding with the spherical portion are provided on the inner surface. And a so-called ball joint composed of a spherical portion provided in the above. In the case of a rocking bearing using such a ball joint, the structure is simple, and the ball bearing can be manufactured at low cost. However, since the contact portion between the inner spherical portion and the outer spherical portion is in a sliding state, this contact portion Are easily worn and it is difficult to ensure sufficient durability.

[0006] Also, the one using such a ball joint is
Since the whole is forged, it is difficult to make the shape of the sliding portion highly accurate, and since the spherical portion and the spherical portion are loosely contacted, it is difficult to secure sufficient rigidity. Because of this,
There is a possibility that the overall length of the bearing expands and contracts with a change in load, or that the parallel link mechanism using this bearing cannot ensure sufficient motion accuracy. In addition, since such a bearing has a structure in which the spherical portion covers most of the outside of the spherical portion,
It is inevitable that the overall length of the bearing becomes large, which causes a size increase of a moving device using the parallel link mechanism.

[0007] Further, instead of each of the above-mentioned rocking bearings 8, 8, a joint device incorporating a plurality of rolling bearings may be used.
This has been done conventionally. However, in order to freely support the corner of the moving table 3 or the fixed table 2 with respect to the end of the first link element 5 or the second link element 6, the above joint The device must incorporate at least three rolling bearings. For this reason, it is inevitable that each of these coupling devices becomes large, which causes an increase in the size of the moving device using the parallel link mechanism. Further, in order to secure the rigidity of each swing support portion, it is necessary to adjust the internal clearance of each rolling bearing constituting the joint device provided in each swing support portion, and the assembling work becomes troublesome.

[0008] Japanese Patent Nos. 2556820 and 258
It is also conceivable to use a rolling bearing described in US Pat. No. 9276, in which a plurality of balls are provided between the outer surface of a sphere and the inner surface of a spherical housing, as the swing bearings 8. However, even when the rolling bearings described in these publications are used, it is still unavoidable that the overall length of the swing bearing becomes large. In addition, when this rolling bearing is used, it is troublesome to incorporate a plurality of balls into the spherical housing. In addition, the preload set to ensure the rigidity of the bearing is affected by the shape accuracy of the plurality of balls and the outer surface of the sphere and the inner surface of the spherical housing that comes into contact with the plurality of balls. It is difficult to build a properly secured bearing stably. When the number of balls to be incorporated in the bearing is small, the arrangement of these balls may be shifted to either side in the bearing, and the rigidity of the bearing may be uneven.

It is also conceivable to use the bearings described in Japanese Patent No. 2614430 or Japanese Patent Application Laid-Open No. H11-125237 to form the above-mentioned rocking bearings 8. That is, in each of these publications, a plurality of balls are provided between an outer ring in which two members are integrally joined to form an inner surface having a partially spherical shape, and a spherical portion disposed inside the outer ring. A bearing in which a ball is rollably held by a cage is described. When such a bearing is used, the incorporation of each ball is relatively good, and the arrangement of each ball is biased to either side inside the bearing, so that the rigidity of the bearing is uneven. I can eliminate things. However, a stable production of a bearing with an appropriate preload set to ensure the rigidity of this bearing is
After all it is difficult.

Japanese Patent Application Laid-Open No. 2000-230546 discloses a rocking bearing to which the structure of a self-aligning ball bearing is applied. In the case of the rocking bearing described in this publication,
Various effects can be obtained, for example, it is easy to stably produce a bearing having a preload set to an appropriate value for securing the rigidity of the oscillating bearing. However, in the case of the rocking bearing described in this publication, the corner of the fixed base 2 or the movable base 3 is attached to the end of each of the first link elements 5, 5 or the second link elements 6, 6. On the other hand, when swinging, the contact part between each ball incorporated inside and the inner peripheral surface of the outer ring is in a slip state, so to reduce the swing torque and ensure sufficient durability, There is still room for improvement.

In view of such circumstances, the present inventor has previously considered an oscillating bearing as disclosed in Japanese Patent Application No. 2000-384631. This rocking bearing includes an inner ring, an outer ring, and a plurality of balls. And, among the inner ring and the outer ring, a plurality of engagement grooves having an arc-shaped cross section are intermittently arranged in the circumferential direction on the circumferential surface of each half in the axial direction of at least one raceway ring, respectively. It is formed at right angles to the circumferential direction. Further, the distance between the bottom surface of each of the engagement grooves and a mating surface whose bottom surface is diametrically opposed is made uniform in the axial direction. The plurality of balls are provided between the engagement grooves and the mating surface, one for each of the engagement grooves, and freely roll along the engagement grooves and the mating surface. And

According to the oscillating bearing disclosed in Japanese Patent Application No. 2000-384631, the problems caused by the above-mentioned structure can be eliminated. That is, since the swing of the member supporting the inner ring with respect to the member supporting the outer ring can be performed by rolling of the plurality of balls, sufficient rigidity and durability can be ensured, and the swing torque can be reduced. In particular, the rigidity can sufficiently secure not only the radial rigidity but also the axial rigidity. In addition, it becomes easy to stably produce the oscillating bearing with an appropriate preload. Further, the overall length of the oscillating bearing is reduced, so that the size of the device incorporating the oscillating bearing can be reduced, and the work of assembling the balls can be easily performed.

[0013]

SUMMARY OF THE INVENTION As described above, Japanese Patent Application No.
In manufacturing the structure of the prior invention disclosed in Japanese Patent Application No. 0-384631, a solid material such as a steel bar is subjected to cutting to form an entire ring shape, and an outer peripheral surface or an inner peripheral surface of the material. It is conceivable that a plurality of engagement grooves are formed in the groove. For example, when processing the material, the material is processed under numerical control using a so-called 5-axis control machining center equipped with a processing tool such as a ball end mill.

However, when a plurality of engaging grooves are formed on the peripheral surface of the solid material after the solid material is cut to form an annular material, the material should be removed from the solid material. Not only does the amount of material increase, the material cost increases, but also the processing time increases, which causes the cost of the oscillating bearing to increase. The present invention has been made in view of such circumstances in order to obtain a small and high-performance rocking bearing at low cost.

[0015]

A swing bearing manufactured by the manufacturing method of the present invention is provided with an inner ring fixed to one of a support member and a link, and provided on an outer peripheral surface of the inner ring. A partial spherical portion having a shape that becomes at least a part of the outer peripheral surface when both ends of the sphere are cut, and provided around the inner ring, and fixedly connected to the other member of the support member and the link An outer ring whose inner peripheral surface is an outer partial spherical portion concentric with the above-mentioned partial spherical portion, and a circumferential direction of a peripheral surface of each half in an axial direction of at least one of the outer rings and the inner ring. Engagement that is formed intermittently at a plurality of locations and is formed at right angles to the circumferential direction, so that the distance between the bottom surface of the circular cross section and the mating surface whose bottom surface is diametrically opposed is uniform in the axial direction. Between the groove and each of the engagement grooves and the mating surface. Each engagement groove, each comprising a plurality of balls provided as freely rolling along the respective engaging grooves and the mating surface.

In particular, in the manufacturing method of the oscillating bearing of the present invention, when manufacturing the bearing ring having the above-mentioned engagement groove, the material is subjected to forging or by sintering a metal powder. After the whole ring material is manufactured, the engaging groove is formed by polishing the outer peripheral surface or the inner peripheral surface of the ring material.

In the method for manufacturing a rocking bearing according to the present invention, each part of the inner ring and the outer ring, each of which is made of steel, is formed into a predetermined size and shape, and then the outer peripheral surface of the inner ring is formed. A plurality of steel or ceramic balls whose surfaces have been subjected to nitriding treatment are incorporated between the outer ring and the outer peripheral surface.

[0018]

According to the method of manufacturing a rocking bearing of the present invention having the above-described structure, when manufacturing a bearing ring having an engagement groove, the amount of material to be removed when machining the bearing ring is determined. Can be reduced. For this reason, the material cost can be reduced, the processing time can be shortened, and the cost of the oscillating bearing can be reduced.

Further, according to the manufacturing method of the oscillating bearing according to the second aspect, it is possible to improve the fretting resistance of the obtained oscillating bearing, and to sufficiently maintain the period until the oscillating bearing requires maintenance. And sufficient rigidity can be ensured.

[0020]

1 to 3 show a first embodiment of the present invention. First, the structure of the swing bearing 8 obtained by the manufacturing method of the present embodiment will be described. This swing bearing 8
Is used for a swing support portion of the parallel link mechanism, and includes an inner ring 13 and an outer ring 1 provided around the inner ring 13.
5 and a plurality of balls 17, 17. this house,
The outer peripheral surface of the inner ring 13 is provided with a partial spherical portion 14 having a shape that becomes the outer peripheral surface when both ends of the sphere are cut. The inner ring 13 is externally fitted and fixed to an end of the first link element 5 or the second link element 6 (see FIG. 5).

The outer ring 15 is formed by joining and fixing a first outer ring element 18 and a second outer ring element 19, each of which is annular, in a state where they are concentrically overlapped with each other. The outer diameter of the first outer ring element 18 is larger than the outer diameter of the second outer ring element 19. Therefore, in a state where the first and second outer ring elements 18 and 19 are combined to form the outer ring 15, a portion corresponding to the first outer ring element 18 on the outer peripheral surface of the outer ring 15 has a diameter. A flange portion 20 protruding outward in the direction is formed over the entire circumference. The first and second outer ring elements 18 and 19 are provided with coupling holes 16a and 16b at a plurality of positions (six in the illustrated example) in the circumferential direction where they are aligned with each other. 1
9 is formed so as to penetrate in the axial direction. By inserting a plurality of bolts (not shown) into the coupling holes 16a and 16b in a state where the first and second outer ring elements 18 and 19 are superimposed on each other, the two outer ring elements 18 and 19 are 1
9 are connected to each other.

On the other hand, the first and second outer ring elements 18, 1, which are provided for each half in the axial direction on the inner peripheral surface of the outer ring 15.
9 are provided with six engaging grooves 21a and 21b each having an arc-shaped cross section (a total of twelve engaging grooves) intermittently and equidistantly in the circumferential direction with respect to the circumferential direction. It is formed in a right angle direction (left and right directions in FIGS. 1 and 3 and front and back directions in FIG. 2). The bottom surfaces 24, 24 of the respective engagement grooves 21a, 21b are the mating surfaces described in claim 1.
The partial spherical portion 14 is located on a single virtual spherical surface with the center of curvature o as its center. In the case of this example, each of the engagement grooves 21a and 21b is
And the second outer ring element 19 are provided at the same position in the circumferential direction (in a state where the phases in the circumferential direction are matched).
The engagement grooves 21a, 21b are provided between the engagement grooves 21a, 21b and the outer peripheral surface of the partial spherical portion 14.
Each of the steel balls 17 is provided so as to freely roll along the outer peripheral surface of each of the engagement grooves 21a and 21b and the partial spherical portion 14. Therefore, in the case of this example, two balls 1 are provided at the same position in the circumferential direction between the inner peripheral surface of the outer ring 15 and the outer peripheral surface of the inner ring 13.
7, 17 exist. Each of the engagement grooves 21a, 21b
The difference between the radius of curvature of the bottom surfaces 24, 24 and the radius of curvature of the partial spherical portion 14 is equal to or slightly smaller than the diameter of each of the balls 17, 17.
Also, on the inner peripheral surface of the outer ring 15, each of the engagement grooves 21a, 21
An outer partial spherical portion 28 concentric with the partial spherical portion 14 is formed in a portion deviated from b.

Further, when the swing bearing 8 is used,
Even if the outer wheels 13 and 15 swing, the swing is limited to a certain range as described later. Even if the outer race 15 swings relative to the inner race 13 within this range, the balls 17, 17 are diametrically spaced from the center axis a of the inner race 13 on the outer peripheral surface of the partial spherical portion 14. Rolling beyond the maximum outer diameter portion 22 where the length is maximum is prevented. Therefore, when the oscillating bearing 8 is used, the balls 17, 17 are always located on only one side with respect to the maximum outer diameter portion 22 defined for each of the balls 17, 17. Therefore, the outer ring 15 and the inner ring 13
When an axial load is applied in any direction between the maximum outer diameter portion 2 of the balls 17, 17.
Half of the balls 17, 17 existing on either side (opposite to the acting direction of the axial load) with respect to 2, receive the force in the compressing direction to support the axial load.

In the case of the present embodiment, mounting holes 23, 23 are provided at a plurality of locations (six in the example shown) in the circumferential direction of the flange portion 20 provided on the outer peripheral surface of the outer ring 15, respectively. 20 is formed so as to penetrate in the axial direction.
A bolt (not shown) for fixing the flange portion 20 to the fixing base 2 or the moving base 3 (see FIG. 5) as a supporting member can be inserted into each of the mounting holes 23, 23. Further, in the case of this example, the space inside the oscillating bearing 8, that is, the space in which the balls 17, 17 are installed between the inner peripheral surface of the outer ring 15 and the outer peripheral surface of the inner ring 13, A solid oil (not shown) is provided. The solid oil lubricates the rolling portions of the balls 17,17. As such a solid oil, for example, various conventionally known oils can be used in addition to a lubricant-containing polymer obtained by solidifying a mixture of a synthetic resin and a lubricant.

The oscillating bearing 8 configured as described above includes the end of the first link element 5 or the second link element 6 and the movable base 3 or the fixed base 2 ( (See FIG. 5). For this reason, in the case of this example, the flange portion 20 provided on the outer race 15 and the corner of the movable base 3 or the fixed base 2 are connected to each of the mounting holes 2.
3 and 23 are connected and fixed by a plurality of bolts (not shown) inserted. Then, the inner ring 13 is externally fitted and fixed to an end of the first link element 5 or the second link element 6.

In particular, in the method of manufacturing a swing bearing according to the present invention, a method of manufacturing the outer ring 15 in which the plurality of engagement grooves 21a and 21b are provided on the inner peripheral surface is devised. That is, in the present invention, when manufacturing the outer ring 15, first,
The first and second outer ring elements 18, 1 constituting this outer ring 15
9 are formed by forging two steel materials or by sintering steel powder, thereby forming a half of the outer partial spherical portion 28 on the inner peripheral surface. The formed two ring materials are made. Then, a plurality of engagement grooves 21a and 21b are formed by polishing the inner peripheral surface of each of the ring materials to form the first and second outer ring elements 18 and 19. Then, the first and second outer ring elements 18 and 19 manufactured as described above are combined in a state where they are overlapped with each other to form the outer ring 15.

When the inner ring 13 is manufactured, a forging process is performed on a steel material, or a steel powder is sintered to form an annular ring material as a whole. Polishing the outer peripheral surface of the
To form After the respective portions of the inner ring 13 and the outer ring 15 are formed to have predetermined dimensions and shapes, each of the engagement grooves 2 formed on the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 15 is formed.
A plurality of balls 17, 17 are incorporated between 1a and 21b. Moreover, in the case of this example, each of these balls 17,
As No. 17, a steel material formed into a spherical shape having a predetermined dimension and then subjected to nitriding on the surface is incorporated.

According to the swing bearing 8 obtained by the manufacturing method of the swing bearing according to the present invention having the above-described structure, a plurality of end portions of the movable base 3 or the fixed base 2 are connected to the first links. The end of the element 5 or each second link element 6 can be swingably supported. That is, as shown in FIG.
When the two shafts a and b are displaced from each other so that the two axes a and b of the inner and outer wheels 13 and 15 do not coincide with each other, and the two axes a and b are inclined with respect to each other by the angle θ, the balls 17, 1
7 is the engagement grooves 21a and 21b and the partial spherical portion 1
By rolling along the outer peripheral surface of No. 4, the central axis a,
The displacement between b is allowed. In addition, such inner and outer wheels 13,
The swing displacement between the first and second balls 15 and 17 may be caused by the end of the first link element 5 or the second link element 6 abutting against a part of the outer race 15 or by the balls 17 and 17 being engaged by the respective engagement grooves 21a. , 2
1b until it reaches the outer end. However, in an actual general use state, even if the two axes a and b are inclined by the angle θ, the balls 17, 17 are maintained at the center of curvature of the partial spherical portion 14 (= the inner and outer wheels 13). , 15) is displaced by only about (0.4 × θ). For this reason, if an appropriate stopper mechanism is provided, each of the balls 17, 1 before the end of the first link element 5 or the second link element 6 abuts against a part of the outer ring 15.
7 does not reach the ends of the inner and outer wheels 13 and 15 and fall off from the ends.

In order to easily realize the moving device 1 in which the movable table 3 is inclined at all angles with respect to the fixed table 2 or in which the inclined movable table 3 is horizontal, a parallel link mechanism is configured. The swing support portion provided at one end of each leg 9 (see FIG. 5) preferably has three degrees of freedom. For example, the swing bearing 8 obtained by the manufacturing method of the present example is provided between the corner of the movable base 3 and the end of the first link element 5, which is the other end of each of the legs 9. In this case, the swing support portion can realize two degrees of freedom in which only the swing displacement is allowed between the corner of the moving table 3 and the end of the first link element 5. In this case, a part of the swing bearing 8 provided between the corner of the fixed base 2 and the end of the second link element 6, which is one end of each leg 9, is provided. By providing a structure that allows relative rotation between the corner of the fixed base 2 and the end of the second link element 6, three degrees of freedom are realized by the swing support portion. In this way, the swing support at one end of each leg 9 is
If the degree of freedom can be realized, it is possible to easily realize the moving device 1 in which the movable base 3 is inclined at all angles with respect to the fixed base 2 or the inclined movable base 3 is horizontal. Therefore, the swing support portion constituted only by the swing bearing 8 obtained by the manufacturing method of this embodiment is preferably provided only at one of the two end portions of each of the leg portions 9.

In particular, in the case of the manufacturing method of the oscillating bearing of the present invention, when manufacturing the outer ring 15 having the plurality of engagement grooves 21a, 21b, the first and second outer ring elements 18, 19 are constituted. By forging the two materials to be formed or by sintering the metal powder, the two ring materials are formed in a ring shape. A plurality of engagement grooves 21a and 21b are formed by polishing at a plurality of locations on the inner peripheral surface of each ring material in the circumferential direction. Therefore, according to the present invention, the cutting process is performed on two solid materials to form an annular material, and then, compared with the case where an engagement groove is formed on the inner peripheral surface of the annular material, The amount of material to be removed when processing the outer ring 15 can be reduced. For this reason, the material cost can be reduced, and the processing time can be shortened, so that the cost of the oscillating bearing 8 can be reduced.

Further, in the case of the present embodiment, a plurality of steel balls 17, 17 whose surfaces have been subjected to nitriding treatment, are incorporated between the inner peripheral surface of the outer ring 15 and the outer peripheral surface of the inner ring 13. Therefore, according to the present invention, in the obtained oscillating bearing 8, the rolling surfaces of these balls 17, 17 and the engagement grooves 21 a, 21 b
And the contact portion between the first and second partial spherical portions 14 is in a state where different materials are in contact with each other.
Fretting on the a, 21b and the partial spherical portion 14 can be suppressed. Accordingly, it is possible to sufficiently secure a period until maintenance is required in the swing bearing 8 and to secure sufficient rigidity. On the other hand, a rocking bearing that incorporates a simple steel ball whose surface is not subjected to nitriding between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, each of which is made of steel, Therefore, the fretting tends to occur. That is, in the swing bearing, each of the balls 17, 17 is connected to each of the engagement grooves 21 a, 21 b and the partial spherical surface within a relatively narrow range between the engagement grooves 21 a, 21 b and the partial spherical portion 14. It reciprocates while rolling along with the part 14. For this reason, if the material and surface treatment of each of the balls 17, 17 are not particularly taken into consideration, the above-described engagement grooves 21a, 21b and the partial spherical portion 14 are subjected to fretting by using the swing bearing for a long period of time. It is easy to occur. When fretting occurs in this manner, the internal clearance of the oscillating bearing changes and the rigidity becomes unstable. In addition, since significant fretting occurs relatively early, the time required for maintenance is shortened. In the case of the present invention, as described above, each of the balls 1
As steels 7 and 17 whose surfaces are subjected to nitriding treatment are incorporated, fretting is less likely to occur during use, and a sufficient period until maintenance is required with the oscillating bearing 8 can be secured. Sufficient rigidity can be ensured.

Further, according to the oscillating bearing 8 obtained by the manufacturing method of this embodiment, any of the problems which occur in the above-mentioned conventional oscillating bearing can be eliminated. That is, according to the swing bearing 8 obtained by the manufacturing method of the present invention, the swing of the movable base 3 or the fixed base 2 with respect to the first link element 5 or the second link element 6 is performed by the plurality of balls 17. Because it can be done by rolling 17
The rigidity and durability of the oscillating bearing 8 can be sufficiently ensured. First, in the case of the present invention, as described above, each of the balls 17, 17 effectively supports not only a radial load but also an axial load in any direction. Therefore, not only the radial rigidity but also the axial rigidity can be sufficiently increased. In the case of the oscillating bearing 8 obtained by the manufacturing method of the present invention, it is necessary to set a preload in order to secure the rigidity of the oscillating bearing 8. The preload is applied to each of the engagement grooves 21a provided on a part of the inner peripheral surface of each half in the axial direction of the outer ring 15,
21b and a partial spherical portion 14 provided on the outer peripheral surface of the inner ring 13
And the respective balls 17, 17 are greatly affected by the shape accuracy and dimensional accuracy. On the other hand, each of these engagement grooves 21a, 2
Ensuring the shape accuracy and dimensional accuracy of the ball 1b, the partial spherical portion 14, and the balls 17, 17 can be relatively easily performed. For this reason, it is easy to stably produce the oscillating bearing 8 that secures an appropriate preload. If an appropriate preload can be applied to the oscillating bearing 8 in this manner, the ball 1
7, 17 and the engagement grooves 21a, 21b and the partial spherical surface portion 1
By eliminating the gap between the oscillating bearing 8 and the sway bearing 4, the rigidity of the oscillating bearing 8 in the radial and axial directions can be sufficiently ensured.
As a result, it is possible to sufficiently secure the rigidity and the motion accuracy of the moving device 1 configured by incorporating the swing bearing 8.

The adjustment for applying an appropriate preload to the oscillating bearing 8 is performed by adjusting each of the balls 17 and 17 incorporated therein.
By appropriately selecting the outer diameter of As such balls 17, 17, those conventionally incorporated in ball bearings can be used as they are, and some of the balls incorporated in these ball bearings have different outer diameters in units of μm. It is easy to make the above adjustment. Further, such adjustment can be easily performed by providing a spacer having a predetermined thickness between the first outer ring element 18 and the second outer ring element 19, in addition to the above-described method. Further, in the case of the oscillating bearing 8 obtained by the manufacturing method of the present invention, the oscillating movement between the inner and outer wheels 13, 15 is controlled by the plurality of balls 17, 1
7, the frictional force generated at the time of the swing can be made sufficiently small, and the driving force required to operate the moving device 1 can be made sufficiently small.

Further, in the case of this example, each of the balls 1
Even if a retainer for holding the balls 7 and 17 is not provided, the rocking can be performed by guiding and rolling the balls 17 and 17 by the engaging grooves 21a and 21b. Therefore, it is possible to prevent the balls 17, 17 from being biased to either side in the oscillating bearing 8 to make the stiffness of the oscillating bearing 8 non-uniform (particularly, the axial stiffness in a specific direction is reduced). it can. Furthermore, the omission of the retainer,
Cost can be reduced.

Further, engagement grooves 21a and 21b provided at a plurality of circumferential positions on the inner peripheral surface of each half of the outer race 15 in the axial direction.
Each of the balls 17 is provided between each of the engagement grooves 21a and 21b. Therefore, the plurality of balls 17, 17
Can be increased (to 12 in this example). As described above, even when the axial load is applied in any direction, the half balls 17 and 17 receive the axial load by receiving the force in the compressing direction. The bearing rigidity of the dynamic bearing 8 can be sufficiently ensured. Moreover, each of the balls 17, 1
7 can be easily assembled into the outer peripheral surface of the inner race 13 and the inner peripheral surface of the outer race 15 at both ends of the inner and outer races 13, 15 near both ends in the axial direction. I can do it. Furthermore, since the partial spherical portion 14 provided on the outer peripheral surface of the inner ring 13 becomes the outer peripheral surface when both ends of the sphere are cut, compared with the case where the member provided inside the outer ring 15 is formed in a spherical shape. Thus, the overall length of the swing bearing 8 can be reduced. Therefore, downsizing of the moving device 1 using the parallel link mechanism incorporating the swing bearing 8 can be achieved.

In the case of this embodiment, the inner ring 13 is freely connected and fixed to the end of the first link element 5 (or the second link element 6), and the outer ring 15 is connected to the movable base 3 ( Alternatively, it can be fixedly connected to the end of the fixing base 2). However,
In the case of the present invention, the inner ring 13 can be externally fitted and fixed to a shaft fixed to the end of the movable base 3 (or the fixed base 2), and the outer ring 15 can be connected to the first link element 5 (or the second Of the link element 6) can be freely coupled and fixed.

FIG. 4 shows a second embodiment of the present invention.
An example is shown. Oscillating bearing 8 obtained by the manufacturing method of this example
In the case of a, the swing bearing 8 obtained in the case of the first example described above is used.
Unlike the case of FIG. 1 and the like, the outer peripheral surface of the inner ring 13 and the outer ring 1
5, a pair of retainers 25, 25 are provided. Each of the retainers 25, 25 has a substantially L-shaped cross section and is entirely formed into an inclined cylindrical shape by injection molding of a synthetic resin. And, at a plurality of places at equal intervals in the circumferential direction of the inclined cylindrical portion 26 constituting each of the retainers 25, 25,
Inside each of them, a pocket 27 capable of holding the balls 17 is formed.

The retainers 25 are arranged between the outer peripheral surface of the inner race 13 and the inner peripheral surface of the outer race 15. Inside each pocket 27 provided in each of the retainers 25, 25, balls 17, 17 in each row provided for each half of the inner ring 13 and the outer ring 15 in the axial direction are provided, respectively.
It is held so that it can roll freely one by one. The large-diameter-side edges of the inclined cylindrical portions 26, 26 constituting the retainers 25, 25 abut against each other. Further, when the movable base 3 or the fixed base 2 (see FIG. 5) is swung with respect to the first link element 5 or the second link element 6, the holders 25, 25 are tilted by the tilts. In a state where the large-diameter-side edges of the cylindrical portions 26, 26 abut against each other, the cylindrical portions 26, 26 swing in synchronization with each other.

In the case of the present embodiment, each ball 17 to be incorporated between the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 15,
17 is made of ceramic. When manufacturing the rocking bearing 8a, after forming the respective parts of the inner ring 13 and the outer ring 15 into a predetermined shape and dimensions, the members formed on the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 15 are formed. Mating groove 21
The balls 17, 17 are assembled between the balls 17a, 21b.

In the case of the manufacturing method of the oscillating bearing of the present embodiment configured as described above, a plurality of ceramic balls 17 are provided between the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 15.
17 is incorporated. For this reason, the obtained rocking bearing 8a
The rolling surface of each of the balls 17, 17 and the inner race 13
The contact portion between the outer peripheral surface of the inner ring 13 and each of the engagement grooves 21a and 21b is in a state where different kinds of materials are in contact with each other. In use, the partial spherical portion 14 which is the outer peripheral surface of the inner ring 13 and each of the engagement grooves 21a, 21 Fretting can be less likely to occur on 21b. Accordingly, it is possible to sufficiently secure a period until maintenance is required in the swing bearing 8a and to secure sufficient rigidity.

Incidentally, the oscillating bearing 8a obtained in the case of the present example is composed of 1
The provision of the pair of cages 25 increases the component cost as compared with the swing bearing 8 obtained in the first example. However,
In the case of this example, the inner ring 13 is
Between the outer peripheral surface of the outer ring 15 and the inner peripheral surface of the outer ring 15.
The work of incorporating 7, 17 becomes easy. In other words, this assembling work is performed between the outer peripheral surface of the inner race 13 and the inner peripheral surface of the outer race 15, in each pocket 27, in each pocket 17,
It is only necessary to assemble the above-mentioned retainers 25, 25 into which the assembly 17 is incorporated. It is not necessary to adjust the installation position independently for each ball 17. Therefore, each of the balls 17, between the outer peripheral surface of the inner race 13 and the inner peripheral surface of the outer race 15,
17 can be more easily performed than in the case of the above-described first example, and the assemblability can be improved.

In the case of this embodiment, each of the retainers 25,
25 are made of a synthetic resin.
For Nos. 5 and 25, a metal plate such as a steel plate can be press-formed or cut out (cut) from a metal material.
However, in the case of the present example in which each of the retainers 25, 25 is made by injection-molding a synthetic resin, the cost can be easily reduced. Other configurations and operations are the same as those in the above-described first example, and thus redundant description will be omitted.

In each of the above-described examples, a plurality of engagement grooves 21a and 21b are formed on the inner peripheral surface of the outer ring 15, and the outer peripheral surface of the inner ring 13 is simply a partial spherical portion 14. However, in the present invention, the inner ring For each half in the axial direction of the outer peripheral surface of the thirteen, a plurality of engaging grooves having an arc-shaped cross-section
Each can be formed in a direction perpendicular to the circumferential direction. In this case, the inner peripheral surface of the outer ring 15 may be a mere partial spherical surface portion that does not form an engagement groove, or, similarly to each of the above-described examples, the inner peripheral surface of the outer ring 15 may be formed in an axial direction. A plurality of engagement grooves 21a and 21b are formed for each half.

When manufacturing the inner ring 13 having a plurality of engagement grooves formed on the outer peripheral surface as described above, a metal material such as steel is forged, or a powder metal such as steel is sintered and formed. After the whole ring material is manufactured, the outer circumferential surface of the ring material is polished to form the plurality of engagement grooves at a plurality of positions on the outer circumferential surface of the inner ring 13.

[0045]

The method of manufacturing a rocking bearing according to the present invention is constructed and operates as described above, so that a small and high-performance rocking bearing can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 shows a first example of an embodiment of the present invention in a state where it is coupled to a first link element (second link element).
XXC sectional view of FIG.

FIG. 2 is a view from the right side of FIG. 1, showing a state in which a first link element (a second link element) is omitted.

FIG. 3 shows a state in which the inner race is swung with respect to the outer race, FIG.
FIG.

FIG. 4A shows a second example of the embodiment of the present invention,
FIG. 4 is an enlarged sectional view corresponding to a part.

FIG. 5 is a schematic perspective view showing an example of a moving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving device 2 Fixed stand 3 Moving stand 5 First link element 6 Second link element 7 Expansion / contraction function 8, 8a Swing bearing 9 Leg part 10 Piston 11 Cylinder 12 Placed object 13 Inner ring 14 Partial spherical part 15 Outer ring 16, 16b coupling hole 17 ball 18 first outer ring element 19 second outer ring element 20 flange portion 21a, 21b engagement groove 22 maximum outer diameter portion 23 mounting hole 24 bottom surface 25 retainer 26 inclined cylindrical portion 27 pocket 28 outer partial spherical portion

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J012 BB03 DB02 EB01 EB14 FB10 HB01 3J101 AA02 AA32 AA43 AA54 AA63 BA55 DA02 EA02 EA41 FA41 FA42 FA44 GA31 3J105 AA22 AA32 AB49 CA33 CE11

Claims (2)

[Claims] An inner ring fixed to one of a support member and a link, and at least a part of an outer peripheral surface provided on an outer peripheral surface of the inner ring when both ends of a sphere are cut off. A partial spherical surface portion having the following shape, and an outer partial spherical surface provided around the inner ring and fixedly coupled to the other of the support member and the link, the inner peripheral surface of which is concentric with the partial spherical portion. Outer ring, and the outer ring and the inner ring, intermittently at a plurality of circumferential positions on the circumferential surface of each half in the axial direction of at least one of the races, each in a direction perpendicular to the circumferential direction. Formed engagement grooves in which the spacing between the bottom surface and the opposite surface whose bottom surface is diametrically opposed in an arcuate cross-section is uniform in the axial direction, and between each of these engagement grooves and the opposite surface, For each of these engagement grooves, each of these engagement grooves and the mating surface A method of manufacturing a rocking bearing comprising a plurality of balls provided so as to freely roll along,
When manufacturing the bearing ring having the above-mentioned engagement groove, by forging the material, or by sintering the metal powder, after producing the entire annular ring material, the outer peripheral surface of the ring material or A method of manufacturing a rocking bearing in which the engagement groove is formed by polishing the inner peripheral surface. 2. After forming each part of the inner ring and the outer ring, each of which is made of steel, into a predetermined size and shape, a steel whose surface is subjected to nitriding treatment between the outer peripheral surface of the inner ring and the outer peripheral surface of the outer ring. The method for manufacturing a rocking bearing according to claim 1, wherein a plurality of balls made of ceramic or ceramic are incorporated.