JPH081294Y2 - Cross roller bearing for turning - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to, for example, a swivel part, a joint part of an industrial robot,
The present invention relates to a rotating cross roller bearing used in a manipulator rotating portion or the like.

(Prior Art) Conventionally, as this type of cross roller bearing,
As shown in FIG. 4, a roller is provided between the inner ring 100 and the outer ring 101.
102 is rotatably interposed, and the rollers 102 are raceway grooves formed on the respective facing surfaces of the inner ring 100 and the outer ring 101.
The central axes of 103 and 104 were alternately arranged with their central axes intersecting at a right angle, and were held at predetermined intervals by a retainer (not shown). Rollers 10 thus adjacent to each other
By placing the 2 cross, the load capacity against radial load, thrust load, and moment load was enhanced.

As such a conventional example, for example, Japanese Patent Publication No. 46-1832
No. 2 and Japanese Patent Publication No. 60-25653.

(Problems to be solved by the invention) However, in the case of such a conventional example, it is a basic idea to increase the rigidity of the orbiting cross roller bearing, and the roller makes line contact with the roller rolling surfaces of the inner and outer wheels. However, there was no self-centering property, and the inclination of the roller shaft, the assembly error, etc., appeared as the problem of one-sided contact of the roller and skew. In particular, in the "X-type roller bearing" described in JP-B-46-18322, not only the cylindrical surface of the roller but also the end surface of the roller is brought into surface contact with the raceway surface to prevent the roller from moving. If there is an inclination of the roller shaft or an assembly error, there is no escape and excessive stress acts on the roller.

That is, conventionally, each roller is
Although it holds the posture of 102 to prevent skew,
Since the regulation is also limited, the center axis of the roller 102 may swing and skew may occur. FIG. 5 schematically shows a skew occurrence state. Both ends a ₁ and a ₂ of the roller 102 are one-sided against the rolling surface 101a on the outer ring 101 side, and further the roller rolling surface on the inner ring 100 side. The central portion a ₃ of the roller 102 comes into point contact with 100a, and when a load is applied to the roller 102, stress P is applied to each contact surface of both end portions a ₁ and a ₂ of the roller 102 and the central portion a _3. There is a problem that ₁ , P ₂ and P ₃ are concentrated, the smooth operation of the roller 102 is hindered, the roller 102 and the rolling surfaces 100a and 101a are damaged, and durability is deteriorated. When the shape of the raceway groove 104 of the outer ring 101 is incorrect, the outer ring 10 is broken as shown by the two-dot chain line in FIG.
The end portion 102a of the roller 102 comes into partial contact with the rolling surface S formed on the first side, and stress concentrates when a load is applied. In particular, the outer ring 11 has a two-divided structure, and the parallelism between the rolling surfaces of the inner ring 100 side and the outer ring 101 side facing each other may be out of order when assembled, so that one-sided contact of the roller 102 that seems to be good Occurs, the smooth operation of the roller 102 is hindered, and excessive stress concentration causes deterioration of durability of the roller 102 and the rolling surface.

The present invention has been made in view of the above-mentioned conventional problems, and the purpose thereof is to change the concept of increasing the rigidity as in the conventional art, to provide self-centering so as to absorb an assembly error, and The roller is preloaded sufficiently to maintain its basic rigidity against load, and the stress concentration that occurs when the roller is one-sided due to skew or assembly error is reduced, and its durability An object of the present invention is to provide a cross roller bearing for swiveling, which can realize improvement and smooth operation.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, a V having two inclined surfaces on the outer periphery which forms a roller rolling surface having an arc-shaped cross section is formed at a substantially right angle. An inner ring provided with a V-shaped raceway groove, and a V-shaped raceway groove formed on the inner circumference, which faces the raceway groove of the inner ring and has both inclined surfaces forming a roller rolling surface having an arcuate cross-section, at substantially right angles. The outer ring and the inner ring and the outer ring are rotatably interposed between the roller rolling surfaces facing each other of the raceway grooves provided in the inner ring and the outer ring, and the center axes thereof are sequentially arranged substantially at right angles and arranged in a staggered manner. In addition, the outer peripheral surface has an arcuate cross-section and can be swung along the outer peripheral arcuate shape with respect to the roller rolling surface, and the taper hole that communicates with the tapered hole that expands from the center toward both ends inside Through holes are provided to make both ends thinner than the central part. The present invention is characterized by comprising a plurality of barrel-shaped spherical rollers each having a uniform wall thickness all around, and a retainer for holding the plurality of barrel-shaped spherical rollers at predetermined intervals.

(Operation) Therefore, the present invention is a modification of the conventional concept of "high rigidity" to have "self-aligning", and it has a shaft runout of the roller, machining error of the outer ring and the inner ring, and assembly. Even if there is an error etc. and one end of the roller hits one side,
The roller oscillates along the arcuate outer peripheral surface to be self-aligned, and further, the thinned roller end portion is deformed to prevent edge load at the roller end. In addition, since the inside of the roller has a hollow structure with through holes that connect the tapered holes at both ends, it is easier to elastically deform than a solid structure and sufficient preload can be applied, resulting in high rigidity. To be Therefore, it is possible to ensure smooth rotation without rattling under severe use conditions where radial, thrust and moment loads peculiar to the turning cross roller bearing are applied.

In particular, when a preload is applied, the amount of elastic deformation of the roller is larger than that of the solid roller, and the contact width with the roller rolling surface can be increased. When a load is applied to the roller in a direction to eliminate the preload, a gap between the roller and the rolling surface does not open unless the roller is displaced by the amount of elastic deformation of the roller. Compared to the case where preload is applied to the solid roller, the contact state of the roller can be maintained for a longer time, and preload loss can be effectively prevented.

(Example) Below, this invention is demonstrated based on the Example shown in figure. 1 to 4 showing a cross roller bearing for swiveling according to an embodiment of the present invention, reference numeral 1 denotes the whole cross roller bearing, which is an inner ring 2 which is assembled substantially concentrically and is divided into two in a width direction. Outer ring 3 and inner ring 2 of the configuration
Rollers rotatably interposed between the outer ring 3 and the outer ring 3
It consists of 15 and.

The outer peripheral surface of the roller 15 has an arcuate cross section, and the central axes of the inner peripheral surfaces of the inner race 2 and the outer race 3 are substantially right angles between the raceway grooves 5 and 6 formed on the outer peripheral surface of the inner race 2 and the inner circumferential surface of the outer race 3 which face each other. They are arranged in a cross with each other. Each of the raceway grooves 5 and 6 is a V-shaped groove opened at a substantially right angle, and both inclined surfaces of the raceway grooves 5 and 6 form roller rolling surfaces 5a, 5b, 6a and 6b of the roller 15. The roller rolling surfaces 5a, 5b, 6a, 6b have an arc-shaped cross section corresponding to the outer peripheral surface of the roller 15.

On the other hand, 7 is a spacer retainer as a retainer,
The rollers 15 are held at a predetermined interval and the posture of the rollers 4 is maintained in a predetermined direction to prevent skew.

The roller 15 is a barrel-shaped spherical roller, and as shown in FIG. 2, tapered holes 15a, 15a are formed inside the roller 15 so as to expand from the center toward both ends. Both the tapered holes 15a, 15a are formed in the center. They are communicated with each other by a straight hole 15b that is a through hole that is provided. Therefore, both ends of the roller 15 are made thinner than the central part. In addition, 8 is a dust seal.

The cross roller bearing unit 1 having the above configuration is
For example, the outer ring 3 is attached to the fixing base 9 side with bolts 10 and fixtures 11.
The inner ring 2 is fastened to the movable table 12 by the bolts 13 and the fixtures 14. When the movable table 12 rotates relative to the fixed base 9, the inner ring 2 and the outer ring 3 are rotated.
The roller 15 interposed between the respective raceway grooves 5 and 6 rolls between the roller rolling surfaces 5a, 5b, 6a and 6b.

By the way, due to some reason, shaft runout occurs in the roller 15 and a part of both ends of the roller 15 comes into contact with the rolling contact surface, or the machining error of each rolling contact surface 5a, 6a of the outer ring 3 and the inner ring 2, or
Even if the end of the roller 15 is one-sided due to an assembly error of the outer rings 2 and 3, the roller 15 is automatically centered along the arc surface of the outer periphery thereof. Further, as described above, both end portions of the roller 15 are thinner than the central portion and have low rigidity, so that they are easily deformed, and the elastic deformation of the both end portions ensures the smooth operation of the roller 15. Further, this elastic deformation increases the contact area of both end contact parts, and the surface pressure is reduced by this increase, so that excessive stress concentration is prevented from occurring and damage to each roller 15 and rolling surface is prevented. The durability is improved. Further, when the straight hole 15b is provided in the roller 15, the rigidity of the central portion of the roller 4 is small and the stress concentration in the central portion of the roller 15 when skew occurs as shown in FIG. 6 can be effectively relaxed. . Barrel roller 15 like this
By using, it is possible to realize a bearing having a self-centering function. Also, by making the outer peripheral surface of the roller 15 an arc surface, the contact area with the roller rolling surface at both ends of the roller 15 can be further increased in combination with thinning the both ends, and stress concentration is prevented from occurring and durability is achieved. The sex can be further enhanced. The roller 15 has a straight hole 15b for communicating the tapered holes 15a, 15a at both ends therein.
Since it is provided with a hollow structure, it is more likely to be elastically deformed and a sufficient preload can be applied as compared with a solid structure, and high rigidity can be obtained.

Therefore, it is possible to ensure smooth rotation without rattling under severe use conditions in which radial, thrust and moment loads peculiar to such a cross roller bearing for turning are applied.

In particular, when a preload is applied, the amount of elastic deformation of the roller 15 is larger than that of the solid roller, and the contact width with the roller rolling surface can be increased. When a load is applied to the roller 15 in the direction to eliminate the preload, a hollow roller as in the present application does not open a gap between the roller 15 and the roller rolling surface unless the roller is displaced by an elastic deformation amount. 15 can maintain the contact state of the roller for a longer period of time as compared with the case where a solid roller is preloaded, and can effectively prevent preload loss.

Further, in the present embodiment, the spacer retainers 7, ... Are interposed between the rollers 15 to prevent the occurrence of shaft runout, and the rigidity of the both ends of the roller 15 is lowered, and the durability of the bearing is reduced. The property can be further improved.

In addition, as the roller, a conical shape whose outer peripheral surface is bulged in an arc shape may be used.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the concept of increasing the rigidity as in the past is changed to provide the self-aligning property, and a skew is generated or each rolling surface is changed. Even if one end of the roller end partly touches due to the machining error of (1) or the assembling error of the inner and outer rings, the roller swings along the arc-shaped outer peripheral surface to maintain the balance of the contact state of both ends of the roller. Deformation of both ends of the roller which is thinner than the central part absorbs axial runout and partial contact of the roller, thus ensuring smooth operation of the roller. Further, the deformation of the roller can alleviate an excessive stress concentration, and the bearing durability can be improved. Also,
Since the inside of the roller has a hollow structure with through holes communicating the tapered holes at both ends, it is easier to elastically deform than a solid structure and sufficient preload can be applied, resulting in high rigidity. it can. Therefore, it is possible to ensure smooth rotation without rattling under severe use conditions where radial, thrust and moment loads peculiar to the turning cross roller bearing are applied.

In particular, when a preload is applied, the amount of elastic deformation of the roller is larger than that of the solid roller, and the contact width with the roller rolling surface can be increased. Therefore, when a load is applied to the roller in the direction of eliminating the preload, a gap is not formed between the roller rolling surface and the roller deformation surface unless the roller is displaced by the elastic deformation amount of the roller. The roller can hold the contact state of the roller for a longer period of time as compared with the case of applying a preload to a solid roller, and can effectively prevent preload loss.

When preload is applied, the edge load at the time of one-side contact of the roller is promoted, and the problems of applying the preload and eliminating the edge load are problems opposite to each other.However, according to the present invention, tapered holes are formed at both ends. By providing a thin hole and providing a through hole that communicates between the tapered holes, it is possible to simultaneously satisfy two contradictory requirements, that is, a request for high rigidity by applying a preload and a request for eliminating the edge load at the roller end. .

[Brief description of drawings]

1 is a partially broken perspective view of a cross roller bearing for swiveling according to an embodiment of the present invention, FIG. 2 is an enlarged vertical sectional view of the roller of FIG. 1, and FIG. 3 is a perspective view of the bearing of FIG. FIG. 4 is a vertical cross-sectional view of a main part showing a use state, FIG. 4 is a vertical cross-sectional view of a main part of a conventional cross roller bearing, and FIG. 5 is a partial cross-sectional view schematically showing a skew generation state of the bearing of FIG. . Explanation of reference numerals 1 ... Cross roller bearing 2 ... Inner ring, 3 ... Outer ring 15 ... Roller 15a ... Tapered hole

Claims (1)

[Scope of utility model registration request] 1. An inner ring having a V-shaped raceway groove which is formed at a substantially right angle and which has two inclined surfaces forming a roller rolling surface having an arcuate cross section on the outer circumference, and an inner race on the inner circumference facing the raceway groove of the inner ring. An outer ring provided with a V-shaped raceway groove which is formed at a substantially right angle and constitutes a roller rolling surface whose inclined surface has an arcuate cross-section, and a roller having an arc-shaped cross section in which the raceway grooves provided in the inner race and the outer race face each other. It is rotatably interposed between the rolling surfaces, and the center axes of the rollers are alternately arranged with their central axes intersecting at a substantially right angle, and the outer peripheral surface has an arcuate cross section and the outer peripheral arcuate shape with respect to the roller rolling surface. A tapered hole that is swingable along the inside and expands from the center toward both ends, and a through hole that allows the tapered hole to communicate with each other are provided, and both ends are formed thinner than the center part. With a plurality of barrel-shaped spherical rollers in which the wall thickness around the tapered hole is uniformly formed all around Turning cross roller bearings characterized in that it comprises a cage holding the barrel-shaped spherical rollers of the plurality of the predetermined intervals, the.