JP2020143748A - Cross roller bearing - Google Patents

Abstract

To provide a cross roller bearing in which a roller insertion work can be performed efficiently in assembly.SOLUTION: In a cross roller bearing in which an outer ring 1 and an inner ring 2 are integrally formed, and rollers 3 are arranged in a fully rollable state, a roller insertion hole 1c of the outer ring 1 is provided so that its center line C extends in a direction (a tangential direction of a pitch circle P) consistent with a tangent line T of the pitch circle P of the roller 3, and therefore, during a roller insertion work in assembly, force pressing the inner ring 2 in the radial direction does not act on the roller 3 pushed in from the roller insertion hole 1c of the outer ring 1, and the roller 3 is smoothly delivered between the outer ring 1 and the inner ring 2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a cross roller bearing in which rollers are incorporated so that the inclination direction alternately changes in the circumferential direction between the outer ring and the inner ring.

A cross-roller bearing has a plurality of rollers bearing between a pair of inclined race planes formed on the inner peripheral surface of the outer ring and a pair of inclined race planes formed on the outer peripheral surface of the inner ring. It is arranged so that the inclination direction changes alternately in the circumferential direction, and is widely used in industrial machines such as reduction gears for robots as a bearing capable of supporting a large radial load, thrust load, and moment load.

An outer ring and an inner ring are integrally formed on such a cross roller bearing, and at the time of assembly, a roller insertion hole formed in the radial direction from one place on the outer peripheral surface of the outer ring is used to move the roller between the outer ring and the inner ring. Some are designed to be inserted into (see, for example, Patent Document 1). However, in this structure, during assembly work, the rollers need to be inserted between the outer ring and the inner ring while changing the inclination direction one by one, so the rollers are elongated after being manually inserted into the roller insertion holes. Both the method of changing the posture of the roller using a tool and the method of inserting the roller into the roller insertion hole while maintaining the desired posture by the robot have a problem that the cycle time of the roller insertion process becomes long.

On the other hand, as proposed in Patent Document 2, if the roller insertion hole of the outer ring is provided so as to extend in a direction inclined with respect to the radial direction from one place on the outer peripheral surface of the outer ring, the roller is provided at the time of assembly. Can be inserted between the outer ring and the inner ring while sliding on the inner peripheral surface of the roller insertion hole, so the roller insertion work is easier than the one in which the roller insertion hole of the outer ring is provided so as to extend in the radial direction. Therefore, it is considered that the cycle time of the roller insertion process can be shortened.

Japanese Patent No. 3739056 Jikkenhei 6-18728 (Fig. 2)

However, even when the roller insertion hole of the outer ring is provided with an inclination as in Patent Document 2, the roller cannot always be smoothly inserted between the outer ring and the inner ring depending on the inclination angle of the roller insertion hole. , There is a risk of damaging the inclined track surface of the inner ring.

Therefore, an object of the present invention is to provide a cross roller bearing that can efficiently perform roller insertion work at the time of assembly.

In order to solve the above problems, the present invention has an outer ring having a pair of inclined orbital surfaces orthogonal to each other on the inner peripheral surface, an inner ring having a pair of inclined orbital surfaces orthogonal to each other on the outer peripheral surface, and a pair of the outer rings. A plurality of rollers arranged so as to alternately change the inclination direction in the circumferential direction are provided between the inclined raceway surface of the above and the pair of inclined raceway surfaces of the inner ring, and the outer ring and the inner ring are integrally formed. In a cross roller bearing in which the outer ring is linearly provided with a roller insertion hole for inserting a roller between the outer ring and the inner ring at the time of assembly, the roller insertion hole of the outer ring is the center line of the roller insertion hole. A configuration is adopted in which the roller extends in a direction forming an angle smaller than 45 ° with respect to the tangent line of the pitch circle at the intersection with the pitch circle of the roller.

According to the above configuration, during the roller insertion work, the force for pushing the roller in the direction of the center line of the roller insertion hole is transmitted through the roller that comes out of the roller insertion hole and comes into contact with the inclined raceway surface of the inner ring. Since the component force that sends the roller in the tangential direction of the pitch circle is larger than the component force that pushes the inner ring in the radial direction, the roller is smoothly sent between the outer ring and the inner ring, and the roller insertion work is efficient. Can be done well.

Here, if the roller insertion hole of the outer ring is provided so as to extend in the tangential direction of the pitch circle of the roller, it is pushed in the direction of the center line of the roller insertion hole during the roller insertion work. Since the rollers are fed between the outer ring and the inner ring without pushing the inner ring, the workability of the roller insertion work can be improved more reliably.

When the roller insertion hole of the outer ring is closed with a stopcock and the stopcock is fixed to the outer ring with a retaining pin penetrating the stopcock, the bearing is provided by providing the roller insertion hole in the above direction. The force with which the roller pushes the retaining pin through the stopcock during operation is reduced, and it is possible to prevent the retaining pin from breaking and causing operation troubles.

As described above, the cross roller bearing of the present invention is provided with the roller insertion hole of the outer ring inclined at an angle smaller than 45 ° with respect to the tangent of the pitch circle at the intersection of the center line and the pitch circle of the roller. As a result, the roller pushed through the roller insertion hole during the roller insertion work is pushed in the tangential direction of the pitch circle with a force larger than the force pushing the inner ring in the radial direction, without damaging the inclined raceway surface of the inner ring. Since it is designed so that it is smoothly fed between the outer ring and the inner ring, the roller insertion work can be performed efficiently.

Longitudinal front view of the main part of the cross roller bearing of the first embodiment Sectional view taken along line II-II of FIG. (A) and (b) are exploded perspective views of the main parts of FIG. 2, respectively. Explanatory drawing of roller insertion work of cross roller bearing of FIG. Cross-sectional view of the cross roller bearing of the second embodiment corresponding to FIG. (A) to (c) are explanatory views of the relationship between the direction of the roller insertion hole and the workability in the roller insertion work, respectively.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show the cross roller bearing of the first embodiment. This cross roller bearing is incorporated in a speed reducer for a robot, and as shown in FIG. 1, an outer ring 1 having a pair of inclined orbital surfaces 1a orthogonal to each other on the inner peripheral surface and an outer ring 1 having a pair of inclined raceway surfaces 1a orthogonal to each other on the outer peripheral surface are orthogonal to each other. It is arranged between the inner ring 2 having a pair of inclined raceway surfaces 2a and the pair of inclined raceway surfaces 1a of the outer ring 1 and the pair of inclined raceway surfaces 2a of the inner ring 2 so that the inclined directions alternate in the circumferential direction. It includes a plurality of rollers 3. The outer ring 1 and the inner ring 2 are integrally formed, and the rollers 3 are arranged in a state of being in contact with adjacent objects, that is, in a so-called full roller state.

The pair of inclined orbital surfaces 1a of the outer ring 1 extend linearly from the relief groove 1b formed in the central portion of the inner peripheral surface of the outer ring 1 in the axial direction in the axial cross section, and one of them. The inclined track surface 1a is in linear contact with the outer peripheral surface of the roller 3 made of cylindrical rollers. Similarly, the pair of inclined orbital surfaces 2a of the inner ring 2 extend linearly on both sides in the axial direction from the relief groove 2b formed in the central portion of the outer peripheral surface of the inner ring 2 in the axial direction in the axial cross section. One inclined track surface 2a is in linear contact with the outer peripheral surface of the roller 3.

Further, as shown in FIG. 2, the outer ring 1 is provided with a roller insertion hole 1c that linearly penetrates from one place on the outer peripheral surface to the inner peripheral surface, and the roller insertion hole 1c is used when assembling the bearing. The roller 3 is inserted between the outer ring 1 and the inner ring 2. Then, the stopcock 4 that closes the roller insertion hole 1c is fixed to the outer ring 1 by the stopcock 4 and the retaining pin 5 that penetrates the outer ring 1.

Here, the roller insertion hole 1c of the outer ring 1 is a circular hole provided so that its center line C extends in a direction (tangential direction of the pitch circle P) that coincides with the tangent line T of the pitch circle P of the roller 3. A stepped surface 1d is formed in the opening on the inner peripheral side of the outer ring 1.

Further, as shown in FIGS. 2 and 3 (a) and 3 (b), the stopcock 4 has a shape that fits into the roller insertion hole 1c with almost no gap, and the outer ring 1 is on the insertion side into the outer ring 1. A step between a notch surface 4a cut out in a substantially V shape so as to be smoothly continuous with a pair of inclined raceway surfaces 1a and a relief groove 1b of the outer ring 1 when fixed, and an opening on the inner peripheral side of the outer ring 1. It has an end surface 4b that abuts on the surface 1d.

Since this cross roller bearing has the above configuration and the outer ring 1 and the inner ring 2 are integrated (non-separable structure), the outer ring 1 has the inner ring 2 arranged radially inside the outer ring 1 at the time of assembly. The roller 3 is inserted between the outer ring 1 and the inner ring 2 from the roller insertion hole 1c, and then the stopper 4 is fitted into the roller insertion hole 1c of the outer ring 1 to fix the roller 3.

At the time of the roller insertion work, as shown in FIG. 4, a tubular jig 6 having an outer peripheral cylindrical surface having a diameter smaller than that of the roller insertion hole 1c of the outer ring 1 is prepared in advance, and the inside of the tubular jig 6 is prepared. The rollers 3 are arranged and held alternately so that the inclination direction changes. Here, as the tubular jig 6, a jig 6 having a pair of support surfaces 6a orthogonal to each other on its inner peripheral surface is used, and the support surface 6a supports the outer peripheral surface of the roller 3 and one end surface.

Then, with one end of the tubular jig 6 holding the roller 3 inserted into the roller insertion hole 1c of the outer ring 1, the roller 3 held from the other end of the tubular jig 6 while rotating the inner ring 2. By pushing the rows, the rollers 3 may be sequentially fed between the outer ring 1 and the inner ring 2 from one end of the tubular jig 6.

At this time, the roller 3 pushed in from the roller insertion hole 1c of the outer ring 1 is smoothly fed between the outer ring 1 and the inner ring 2 without the force acting to push the inner ring 2 in the radial direction, so that the work is efficient. can do.

Further, since the rollers 3 previously held inside the tubular jig 6 can be continuously fed between the outer ring 1 and the inner ring 2, the rollers are brought into a desired posture one by one and fed between the outer ring and the inner ring. Compared with the conventional method, the cycle time of the roller insertion process can be significantly shortened.

FIG. 5 shows the cross roller bearing of the second embodiment. In this embodiment, based on the first embodiment, the roller insertion hole 1c of the outer ring 1 is provided with respect to the tangent line T of the pitch circle P at the intersection of the center line C of the roller insertion hole 1c and the pitch circle P of the roller 3. It was changed so that it extends in the direction of about 30 °. Further, in line with this, the stepped surface 1d of the opening on the inner peripheral side of the outer ring 1 of the first embodiment and the end surface 4b of the stopcock 4 that abuts on the stepped surface 1d are eliminated.

In this second embodiment, as compared with the first embodiment, a force that pushes the inner ring 2 in the radial direction acts on the roller 3 pushed from the roller insertion hole 1c of the outer ring 1, so that the roller 3 has the outer ring 1 and the inner ring 2. Although it is slightly inferior in terms of smoothness when it is fed into the space, the operation operation is performed because the sloped raceway surface 1a of the outer ring 1 and the notch surface 4a of the stopcock 4 become continuous more smoothly. Can increase the stability of.

Here, the extending direction (center line C) of the roller insertion hole 1c of the outer ring 1 is inclined with respect to the tangent line T of the pitch circle P at the intersection of the center line C of the roller insertion hole 1c and the pitch circle P of the roller 3. The angle (hereinafter referred to as “roller insertion hole inclination angle”) θ is set to about 30 ° in the above-mentioned example of FIG. 5, but can be arbitrarily set as long as it is smaller than 45 ° for the following reason. can do.

That is, as shown in FIG. 6B, when the roller insertion hole inclination angle θ is 45 °, the force F for pushing the roller 3 in the direction of the roller insertion hole 1c hits the inclined raceway surface 2a of the inner ring 2. The component force F ₁ that pushes the inner ring 2 in the radial direction via the tangent roller 3 and the component force F ₂ that sends the roller 3 in the direction of the tangent line T of the pitch circle P have the same magnitude. As shown in c), when the roller insertion hole inclination angle θ> 45 °, F ₁ > F ₂ , and as shown in FIG. 6A, when the roller insertion hole inclination angle θ <45 °, F ₁ <the _{F 2.}

Therefore, if θ ≧ 45 °, the roller 3 may be caught on the inner ring 2 or the inclined raceway surface 2a of the inner ring 2 may be damaged. However, if θ <45 ° is set, the roller 3 is attached to the inner ring 2. It is possible to smoothly feed the inclined raceway surface 2a between the outer ring 1 and the inner ring 2 without damaging it.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Outer ring 1a Inclined track surface 1c Roller insertion hole 1d Step surface 2 Inner ring 2a Inclined track surface 3 Roller 4 Stopcock 4a Notch surface 4b End surface 5 Retaining pin 6 Cylindrical jig 6a Support surface C Center line P of roller insertion hole Roller pitch circle T Roller pitch circle tangent

Claims (3)

An outer ring having a pair of inclined orbital surfaces orthogonal to each other on the inner peripheral surface, an inner ring having a pair of inclined orbital surfaces orthogonal to each other on the outer peripheral surface, a pair of inclined orbital surfaces of the outer ring, and a pair of inclined orbital surfaces of the inner ring. A plurality of rollers arranged so as to alternately change the inclination direction in the circumferential direction are provided between the outer ring and the inner ring, and the outer ring and the inner ring are integrally formed with the outer ring. In a cross roller bearing in which a roller insertion hole for insertion is provided linearly between them.
The roller insertion hole of the outer ring is provided so as to extend in a direction forming an angle smaller than 45 ° with respect to the tangent line of the pitch circle at the intersection of the center line of the roller insertion hole and the pitch circle of the roller. A cross roller bearing that features. The cross-roller bearing according to claim 1, wherein the roller insertion hole of the outer ring is provided so as to extend in the tangential direction of the pitch circle of the roller. The cross roller according to claim 1 or 2, wherein the roller insertion hole of the outer ring is closed with a stopcock, and the stopcock is fixed to the outer ring by a retaining pin penetrating the stopcock. bearing.

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