JPS5928774B2 - Ball spline for compound motion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball spline for compound motion that can perform a combination of linear motion in the axial direction and rotational motion for transmitting torque.

Machines originally consist of a linear motion mechanism and a rotary motion mechanism, and mechanisms that combine these motions are used in many machines, such as spindles of various machine tools, supports and arms of industrial robots, precision indexing axes, riveting machines, and transfer machines. Ball splines are used in machines, automatic conveyance devices, etc., and ball splines used for this purpose are increasingly required to have higher performance.

Conventionally, as a means of configuring a compound motion mechanism using this type of ball spline, for example, the ball spline is assembled inside a cylinder, a gear is assembled on the outside of this cylinder, and a gear is attached to the housing so as to be rotatable. Installing bearings.

However, with this method, in addition to the ball spline, a gear, a cylindrical body for attaching the gear, and a bearing for attaching to the housing are required, which increases the number of parts and increases the product cost. However, no matter how accurately each part is machined, the small machining errors that occur for each part accumulate, making it difficult to achieve high machining accuracy as a whole, and the design is extremely troublesome. It also had many problems, including the difficulty of making it compact. In view of this point of view, this invention
The outer cylinder constituting the spline bearing of the ball spline has a transmission member integrally formed approximately at the center of its outer wall, and mounting bearings used for mounting to the housing are provided at both ends of the outer wall. The object of the present invention is to provide a ball spline for compound motion that can solve the various problems of the above-mentioned conventional means all at once.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

1 to 3, a ball spline for compound motion according to a first embodiment of the present invention is shown.

This ball spline consists of a spline bearing B and a large number of balls 3 incorporated in this spline bearing B.
It consists of a spline shaft S supported by a spline shaft S. The spline bearing B has a transmission member 2 integrally formed substantially in the center of the outer wall along the circumferential direction thereof,
In addition, a guide groove 4a for the load ball 3a is formed on the inner wall and has a substantially U-shaped cross section and extends in the axial direction.Although the depth is substantially the same as that of the guide groove 4a, the width thereof is wider. 4
an outer cylinder 1 having guide grooves 4b for the no-load balls 3b extending in the axial direction alternately with the guide grooves 4a and circumferential guide grooves 4c communicating with both ends of these pairs of guide grooves 4a and 4b; It is formed into a cylindrical shape of hard synthetic resin or the like and is fitted into the outer cylinder 1, and has a long hole 6 at a position corresponding to the guide groove 4a of the load ball 3a. a retainer 5 having a concave groove 7 at a position corresponding to the guide groove 4b, which together with the guide grooves 4a, 4b, and 4c forms an endless track for the ball 3 and prevents the ball 3 from falling off; It is composed of a large number of balls 3 that circulate on the endless track while receiving a load from the spline shaft S as a loaded ball 3a or without receiving a load from the spline shaft S as a non-load ball 3b.

Furthermore, mounting bearings 8 are provided at both ends of the outer wall of the outer cylinder 1 for rotatably mounting the spline bearing B to the housing H.

In this embodiment, the transmission member 2 formed on the outer wall of the outer cylinder 1 is formed as a spur gear. The mounting bearing 8 also includes an outer ring 9, a large number of balls 11 disposed within a rolling cable 10 formed on the inner wall of the outer ring 9, and a retainer 12 that holds these balls 11. It is composed of an angular contact bearing, and steps are formed at both ends of the outer wall of the outer cylinder 1, and the balls 11 of the mounting bearing 8 roll on the corners of the steps when in use. A rolling groove 13 is formed. Furthermore,
The spline shaft S is an axial convex that is fitted into a recess formed by mutually adjacent pairs of rows of load balls 3a that are partially exposed through the elongated hole 6 of the retainer 5 in the spline bearing B. It has the same number of strips 14 as the number of pairs of rows, and is supported by these load balls 3a so as to be slidable in the axial direction.

Therefore, according to the compound motion ball spline of the first embodiment, for example, as shown in FIG. 3, the spline bearing B is fitted into the mounting hole 15 of the housing H via the mounting bearing 8, An idle gear 17 is fixed using a nut 16 while applying preload to each mounting bearing 8, and transmits power to a transmission member 2 formed on the outer wall of the outer cylinder 1.
By meshing the gears, the spline shaft S fitted into the spline bearing B moves linearly in its axial direction, and at the same time receives power from the idle gear 17, etc., the spline bearing B rotates. This allows the spline shaft S to perform a combination of linear motion and rotational motion.

Next, in the second embodiment shown in FIGS. 4 and 5,
Unlike the case of the first embodiment, the transmission member 2 integrally formed approximately at the center of the outer wall of the outer cylinder 1 is a worm gear, and the load ball 3 formed on the inner wall of the outer cylinder 1
The guide groove 4a of a is formed in an R shape that is approximately equal to the ball diameter.
A similar R-shaped rolling groove 18 is formed, and the load ball 3a is formed to roll between the guide groove 4a and the rolling groove 18 while receiving a load.

According to this embodiment, since the transmission member 2 is a worm gear, by stopping the worm 19 that meshes with the transmission member 2, the rotation of the spline bearing B, that is, the rotational movement of the spline shaft S can be controlled as necessary. It can also be stopped and locked.

In each of the above embodiments, the transmission member 2 is formed as a spur gear or a worm gear, but the transmission member 2 may be any member as long as it can transmit power in the rotational direction, for example, it may be a pulley or the like. good.

As described above, in the ball spline for compound motion according to the present invention, the transmission member 2 is integrally formed along the circumferential direction of the outer wall of the outer cylinder 1 forming the groove of the spline bearing B. A housing H is provided at both ends of the outer wall of the outer cylinder 1.
Since a mounting bearing 8 is provided to rotatably hold the outer cylinder 1, the ball spline can be directly mounted to the housing H via the mounting bearing 8, and the transmission installed in the outer cylinder 1 There is no need to form the members separately or to form a cylindrical body for attaching the separate transmission member to the outer cylinder, and the number of parts can be significantly reduced. Therefore, the machining errors that occur in each part do not accumulate and become large machining errors, making it possible to manufacture the whole with high precision, making it compact, and extremely easy to design. become. In addition, according to the present invention, the transmission member 2 is formed along the circumferential direction at the substantially central portion of the outer wall of the outer cylinder 1 constituting the spline bearing B. 2. Probing processing to form guide grooves 4a, 4b, 4c on the inner wall of the cylindrical body; 3. Ball passing through the guide groove 4a of the load ball 3a; 4. Transmission member on the outer wall of the cylindrical body. Turning to form 2, 5
The steps of carburizing and quenching, passing the ball through the guide groove 4a of the 6-load ball 3a, and grinding the outer wall surface of the cylindrical body and the transmission member 2 after assembly to the 7-spline shaft S are adopted. In addition to being able to be formed by turning, the inside of the outer cylinder 1 expands inward at approximately the center of the outer cylinder 1 by carburizing and quenching, thereby producing a so-called crunning effect. Therefore, the workability in manufacturing the outer cylinder 1 is significantly improved, and from this point of view as well, manufacturing costs can be reduced. Furthermore, since the transmission member 2 is integrally formed approximately at the center of the outer wall of the outer cylinder 1, the wall thickness at the center of the outer cylinder 1, where the largest load is applied during torque transmission, is extremely thick. The rigidity of the outer cylinder 1 is significantly improved, and deformation of the outer cylinder 1 during torque transmission can be completely prevented.

In each of the above embodiments, the mounting bearing 8 is constituted by an angular contact bearing consisting of an outer ring 9, balls 11 and a retainer 12.
The angular contact bearings are designed to roll in rolling grooves 13 that are integrally formed at the end of the outer wall of the outer cylinder 1, so the inner ring of each angular contact bearing is omitted and the entire structure can be made compact. .

In the present invention, the position of the transmission member 2 formed on the outer wall of the outer cylinder 1 is expressed as "approximately at the center", but this means that it may be near the center of the outer wall of the outer cylinder 1; Of course, this does not represent only the central part.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an outer cylinder constituting a spline bearing of a ball spline for compound motion according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view showing the attached state of the compound motion ball spline of the first embodiment, FIG. 4 is a partial cross-sectional front view showing the outer cylinder of the spline bearing of the compound motion ball spline of the second embodiment, and FIG. 5 is a sectional view taken along the line - in FIG. 4. FIG. Code explanation, B...Spline bearing, S.
... Spline shaft, H ... Housing, 1 ... Outer cylinder, 2 ... Transmission member,
3...Ball, 8...Bearing for installation, 9...Outer ring, 10...Rolling groove, 1
1...ball, 12...retainer, 13
...Rolling structure.

Claims (1)

[Claims] 1. Comprised of a spline bearing B and a spline shaft S supported by balls 3 incorporated in the spline bearing B, it is a composite shaft that combines linear motion in the axial direction and rotational motion for torque transmission. In the ball spline for motion, the outer cylinder 1 constituting the spline bearing B
A transmission member 2 is integrally formed approximately at the center of the outer wall of the outer wall along the circumferential direction thereof, and mountings are attached to the housing H at both ends of the outer wall of the outer tube 1 to rotatably hold the outer tube 1. A ball spline for compound motion, characterized by being provided with a bearing 8. 2. The ball spline for compound motion according to claim 1, wherein the transmission member 2 is a worm gear. 3. The ball spline for compound motion according to claim 1 or 2, wherein the mounting bearing 8 is an angular contact bearing. 4 The mounting bearing 8 is attached to an outer ring 9 and a large number of balls 11 arranged in rolling grooves 10 formed on the inner wall of the outer ring 9.
The outer cylinder 1 of the spline bearing B has rolling grooves 13 on both ends of its outer wall in which the balls 11 roll. A ball spline for compound motion according to claim 3, characterized in that the ball spline is formed.