TW201730457A - Ball circulating tube and ball screw apparatus capable of easily mounting components engaged outside screw nut and ball circulating tube - Google Patents

Abstract

The present invention provides a ball circulating tube (4), which forms a pathway for connecting two separated portions of a rolling path of a ball screw apparatus (1) so as to circulate the balls (6), such that, while mounting on the ball screw apparatus (1), the outer ends (4a, 4b) disposed at the outer ends of the position farthest from the central axis of a screw shaft (2) in the radial direction are provided with an adjusting zone for adjusting the distance from the central axis line of the screw shaft (2) to the outer ends. Thus, the components engaged outside the screw nut and the ball circulating tube (4) may be easily mounted.

Description

Ball circulation tube, ball screw device

The present invention relates to a ball screw device used as, for example, a steering device or a device for moving a weight, a machining device, a precision positioning device, or the like as a mechanical element that converts a rotary motion into a linear motion.

According to the invention described in Patent Document 1, there is a ball screw device in which a nut circulation pipe is fixed to a nut by covering a nut and a ball circulation pipe in a circumferential direction by a metal sleeve.

Prior technical literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. Hei 10-141465

However, in the prior ball screw device, the depth of the slit formed in the nut to be embedded in the ball circulation pipe or the outer diameter of the nut must be adjusted so that the sleeve or the rotor covering the ball circulation pipe and the nut is replaced. The inner circumferential surface is appropriately in contact with the ball circulation pipe and the nut, so that there is a problem that the adjustment work takes time.

In view of the above problems, an object of the present invention is to provide an externally mountable snail Ball circulation pipe and ball screw device for parts of cap and ball circulation pipe.

In order to solve the above problems, the present invention provides a ball circulation pipe which is used in a ball screw device having a screw shaft having a first spiral groove formed on a periphery thereof, and a screw shaft for passing through the screw shaft a cylindrical portion of the inner cylindrical portion and a nut of the second rolling groove corresponding to the first rolling groove formed on the inner circumferential surface of the cylindrical portion, and a rolling path formed by the first rolling groove and the second rolling groove A plurality of balls are accommodated therein, and the ball circulation pipe forms a path connecting the two portions of the rolling path, and the ball is circulated, and is formed in the radial direction when mounted on the ball screw device. An outer end portion at an outer end away from the center axis of the screw shaft has an adjustment region for adjusting a distance from the center axis to the outer end.

Preferably, the outer end portion is a protruding portion.

Further, it is preferable that the outer end portion is a thick portion formed thicker than the other portion.

Moreover, in order to solve the above problems, the present invention provides a ball screw device comprising: a screw shaft having a first rolling groove formed in a spiral shape on an outer circumference; and a nut having a cylinder through which the screw shaft passes through the inner side a second rolling groove corresponding to the first rolling groove is formed on an inner circumferential surface of the cylindrical portion, and a plurality of balls are housed in a rolling path formed by the first rolling groove and the second rolling groove And a ball circulation pipe that forms a path connecting the two portions of the separation of the rolling paths, so that In the ball circulation pipe, the outer end portion that is disposed at an outer end that is disposed at a position farthest from the central axis of the screw shaft in the radial direction includes a margin for adjusting a distance from the central axis to the outer end.

Preferably, the outer end portion is a protruding portion.

Further, it is preferable that the outer end portion is a thick portion formed thicker than the other portion.

Moreover, it is preferable to further have a fixing member that fixes the ball circulation pipe to the nut.

Moreover, it is preferable that the fixing member has a fixing portion that covers one of the ball circulation pipes from the outside in the radial direction, and a mounting portion that is integrally formed with the fixing portion and that is attached to the cylindrical portion, and the fixing portion is The surface on the outer side of the radial direction forms a curved surface that is disposed on the same cylindrical surface as the outer peripheral surface of the cylindrical portion.

According to the present invention, it is possible to provide a ball circulation pipe and a ball screw device which are easy to mount components externally fitted to the nut and the ball circulation pipe.

1‧‧‧Ball screw device

2‧‧‧Screw shaft

3‧‧‧ nuts

3a‧‧‧Cylinder

3b‧‧‧Flange

3c‧‧‧cutting section

4‧‧‧Ball circulation tube

4a, 4b‧‧‧ protrusions

4c, 4d‧‧‧ thick wall

5‧‧‧ Temporary fixing cover

5a‧‧‧Fixed Department

5b‧‧‧Installation Department

6‧‧‧ balls

7‧‧‧ casing

Fig. 1 is a plan view showing a ball screw device according to a first embodiment.

Fig. 2 is a schematic view showing a cross section of the ball screw device of the first embodiment.

Fig. 3 is a schematic view showing a cross section of the ball screw device of the second embodiment.

Fig. 4 is a schematic view showing a cross section of a ball screw device according to a third embodiment.

Fig. 5 is a plan view showing a ball screw device according to a modification of the first embodiment.

Fig. 6 is a schematic view showing a cross section of a ball screw device according to a modification of the first embodiment.

(First embodiment)

Hereinafter, a ball screw device according to a first embodiment of the present application and a ball circulation pipe attached to the ball screw device will be described with reference to Figs. 1 and 2 .

Fig. 1 is a plan view showing a ball screw device 1 according to the first embodiment. The ball screw device 1 is a screw shaft 2 having a spiral first groove, a nut 3 fitted to the screw shaft 2, and a nut 3 attached to the nut 3 for drawing a plurality of balls 6 (shown in FIG. 2) The circulating ball circulation pipe 4 and the temporary fixing cover 5 which fixes the ball circulation pipe 4 to the fixing member of the nut 3 are comprised.

The nut 3 has a cylindrical cylindrical portion 3a and a flange 3b integrally formed with the cylindrical portion 3a at one end portion of the cylindrical portion 3a and extending radially outward. A second rolling groove corresponding to the first rolling groove formed on the outer circumferential surface of the screw shaft 2 is formed on the inner circumferential surface of the nut 3. The first rolling groove and the second rolling groove form a rolling path for rotating a plurality of balls 6.

Fig. 2 is a schematic view showing a cross section of the ball screw device 1 of the first embodiment. A state in which the metal sleeve 7 is externally fitted to the nut 3 and the ball circulation tube 4 is shown. Further, the sleeve 7 is not a component of the ball screw device 1 of the first embodiment.

A plurality of balls 6 are accommodated between the rolling paths, and the screw shaft 2 and the nut 3 are relatively moved in the extending direction of the screw shaft 2 by being relatively rotated about the central axis of the screw shaft 2.

A notch portion 3c is formed in the cylindrical portion 3a of the nut 3. Both ends of the cutout portion 3c are The outer peripheral surface of the cylindrical portion 3a penetrates to the inner peripheral surface. A ball circulation pipe 4 is inserted into the notch portion 3c.

The ball circulation pipe 4 has a U-shaped overall shape, and the inner side is a cavity that penetrates from one end portion to the other end portion. The ball circulation pipe 4 is inserted into the notch portion 3c of the nut 3 from both end sides. Both ends of the ball circulation pipe 4 are opened to the inside of the rolling path. As a result, the ball 6 that has rotated in the rolling path by the relative rotation of the screw shaft 2 and the nut 3 reaches any one end portion of the ball circulation pipe 4, and is picked up by the ball circulation pipe 4 to enter the ball cycle. The inside of the tube 4 is used and discharged from the other end. In this way, the balls 6 can be infinitely circulated in the rolling path and the ball circulation pipe 4.

In FIG. 2, the ball circulation pipe 4 is fixed to the nut 3 by the sleeve 7, but the ball circulation pipe 4 is temporarily fixed to the snail by the temporary fixing cover 5 before the sleeve 7 is attached. Cap 3.

The temporary fixing cover 5 is composed of a fixing portion 5a that covers the center portion of the ball circulation pipe 4 from the radially outer side of the nut 3, and a mounting portion 5b that is integrally formed with the fixing portion 5a on both sides of the fixing portion 5a. . As shown in FIG. 2, the fixing portion 5a of the temporary fixing cover 5 has a thickness that does not reach the inner circumferential surface of the sleeve 7. In other words, the radially outer surface of the fixing portion 5a of the temporary fixing cover 5 is disposed at a position closer to the central axis than the outer circumferential surface of the cylindrical portion 3a in the radial direction.

The temporary fixing cover 5 can be easily attached to the nut 3 by engaging the mounting portion 5b with the nut formed at the engaging portion of the nut 3. Thereby, it is possible to easily prevent the ball circulation pipe 4 or even the plurality of balls 6 from coming off the nut 3 before the sleeve 7 is attached to the nut 3 of the ball screw device 1, for example, during transportation. Further, since the temporary fixing cover 5 is disposed radially inward of the inner circumferential surface of the sleeve 7, the sleeve 7 can be attached without removing the temporary fixing cover 5, and the ball circulation tube 4 can be prevented from being sleeved. The tube 7 is detached during the installation work.

Further, in the past, as the temporary fixing of the ball circulation pipe 4, the method of covering the ball circulation pipe 4 and the nut 3 by the tubular member is also employed. However, the tubular member can rotate relative to the nut 3, and torque transmission cannot be performed. Cannot be used in a nut-rotating ball screw unit. On the other hand, according to the first embodiment, since the rotor or the like can be attached to the nut 3 so that the torque can be transmitted, the ball screw device 1 can be used for the nut rotation.

The ball circulation pipe 4 has a pair of protrusions 4a and 4b which are disposed so as to protrude outward in the radial direction of the screw shaft 2, on the outer circumferential surfaces of the both sides of the temporary fixing cover 5. The projections 4a and 4b have a substantially hemispherical shape and protrude to a height equal to the cylindrical surface of the outer circumferential surface of the cylindrical portion 3a of the nut 3. Therefore, when the sleeve 7 is externally fitted to the nut 3, the projections 4a, 4b are in contact with the inner circumferential surface of the sleeve 7.

With such a configuration, by adjusting the protruding heights of the protruding portions 4a, 4b, the front ends of the protruding portions 4a, 4b are brought into contact with the inner peripheral surface of the sleeve 7, so that the ball circulation tube 4 can be easily fixed to the nut by the sleeve 7. 3. In other words, the projections 4a and 4b which are disposed at the position farthest from the central axis of the screw shaft 2 as the outer end portions are provided with adjustment regions for fitting the sleeves 7. Thereby, it is not necessary to adjust the shape or size of the depth of the notch portion 3c of the nut 3, the outer diameter of the cylindrical portion 3a of the nut 3, and the shape of the inner circumferential surface of the sleeve 7 in order to attach the sleeve 7. Further, the ball circulation pipe 4 thus constructed can correspond to the nuts 3 of various outer diameters. As an adjustment of the protruding height of the protruding portions 4a and 4b, for example, the protrusions 4a and 4b are raised in advance, that is, the front ends of the protruding portions 4a and 4b are set to be located radially outward of the inner peripheral surface of the sleeve 7. The heights are further subjected to grinding of the projections 4a and 4b in accordance with the outer diameter dimension, the slit depth, the manufacturing error, and the like of the nut 3 to be mounted.

(Second embodiment)

Next, the ball screw device 1 according to the second embodiment of the present application will be described with reference to Fig. 3 . Bright. The ball screw device 1 of the second embodiment is the same as the ball screw device 1 of the first embodiment except for the configuration of the temporary fixing cover. Therefore, in the description of the second embodiment, the same components as those of the ball screw device 1 of the first embodiment are denoted by the same reference numerals as in the first embodiment, and the description of the first embodiment is omitted. The configuration of the fixing cover 5 and the effects unique to the second embodiment will be described.

Fig. 3 is a schematic view showing a cross section of the ball screw device 1 of the second embodiment. As shown in FIG. 3, in the temporary fixing cover 5, the fixing portion 5a that is in contact with the ball circulation pipe 4 is in contact with the inner circumferential surface of the sleeve 7. In other words, in the temporary fixing cover 5, the surface of the radially outer fixing portion 5a has the same radius of curvature as the outer circumferential surface of the cylindrical portion 3a of the nut 3, and is formed to be disposed in the cylindrical portion 3a of the nut 3. A curved surface on the same cylindrical surface as the outer circumference.

According to the second embodiment, in addition to the effects of the first embodiment, the three projections 4a and 4b and the three points of the fixing portion 5a of the temporary fixing cover 5 are adjacent to the inner circumferential surface of the sleeve 7. Therefore, the ball circulation pipe 4 can be fixed more firmly.

(Third embodiment)

Next, a ball screw device 1 according to a third embodiment of the present application will be described with reference to Fig. 4 . The ball screw device 1 of the third embodiment is the same as the ball screw device 1 of the second embodiment except for the configuration of the ball circulation pipe 4. Therefore, in the description of the third embodiment, the components corresponding to those of the ball screw device 1 of the second embodiment are denoted by the same reference numerals as those of the second embodiment, and the description of the second embodiment is omitted, and the ball is omitted. The configuration of the circulation pipe 4 and the effects unique to the third embodiment will be described.

Fig. 4 is a schematic view showing a cross section of the ball screw device 1 of the third embodiment. As shown in FIG. 4, the ball circulation pipe 4 is disposed on the side of the sleeve 7, that is, disposed on the screw. The radially outer portion of the shaft 2 is formed to be thicker than the other portions except for the central portion. In other words, the portion of the ball circulation pipe 4 disposed radially outward of the screw shaft 2 has thick portions 4c and 4d which are oriented in the wall thickness from the center portion of the ball circulation pipe 4 The both end portions are gradually thickened, and the both end portions are formed such that the wall thickness gradually decreases toward the end surface side.

In the third embodiment, the thick portions 4c and 4d function as adjustment regions, and the same effects as those of the second embodiment described above can be obtained.

In the above, the specific embodiments have been described in order to facilitate the understanding of the present invention. However, the present invention is not limited to the embodiments, and various modifications and improvements can be made.

For example, the shape of the protruding portions 4a and 4b is not limited to the shape of the above embodiment, and various shapes that can function as adjustment regions can be employed. For example, a conical shape, a semi-cylindrical shape or the like can be employed

Further, in the above-described embodiment, the temporary fixing cover 5 is used to temporarily fix the ball circulation pipe 4 to the nut 3, but the temporary fixing means is not limited thereto. In particular, in the first embodiment, since the temporary fixing cover 5 and the sleeve 7 are not in contact with each other, various temporary fixing means other than the temporary fixing cover 5 can be employed.

As the temporary fixing cover 5, in addition to the above-described embodiment, as shown in Figs. 5 and 6, a temporary fixing cover 5 having a circular shape in plan view and a circumferential portion joined to the nut 3 may be used. According to such a temporary fixing cover 5, it is possible to counteract the force of the ball circulation pipe 4 to be detached from the nut 3 with a good balance in the circumferential direction.

As described above, according to the present invention, it is possible to provide a ball circulation pipe and a ball screw device which are easy to mount components externally fitted to the nut and the ball circulation pipe.

1‧‧‧Ball screw device

2‧‧‧Screw shaft

3‧‧‧ nuts

3a‧‧‧Cylinder

3b‧‧‧Flange

4‧‧‧Ball circulation tube

4a‧‧‧Protruding

4b‧‧‧Protruding

5‧‧‧ Temporary fixing cover

5a‧‧‧Fixed Department

5b‧‧‧Installation Department

Claims (8)

A ball circulation device for use in a ball screw device having a screw shaft having a spiral first groove formed on an outer circumference thereof and a cylindrical portion through which the screw shaft passes inside a nut of a second rolling groove corresponding to the first rolling groove is formed on an inner circumferential surface of the cylindrical portion, and a plurality of balls are accommodated in a rolling path formed by the first rolling groove and the second rolling groove to form a plurality of balls. a path connecting the two portions of the separation of the rolling paths to circulate the balls, and when the ball screw device is attached to the ball screw device, the outer end of the position is disposed farthest from the central axis of the screw shaft in the radial direction. The outer end portion has an adjustment region for adjusting a distance from the central axis to the outer end. The ball circulation pipe of claim 1, wherein the outer end portion is a protrusion. The ball circulation pipe of claim 1, wherein the outer end portion is a thicker portion formed thicker than the other portions. A ball screw device comprising: a screw shaft having a spiral first rolling groove formed on an outer circumference; and a nut having a cylindrical portion through which the screw shaft passes inside, and the cylindrical portion a second rolling groove corresponding to the first rolling groove is formed on the circumferential surface; a plurality of balls are housed in the rolling path formed by the first rolling groove and the second rolling groove; and a ball circulation pipe is formed a path connecting the two portions of the separation of the rolling paths to circulate the balls; The ball circulation pipe has an outer end portion that is disposed at an outer end that is located farthest from the center axis of the screw shaft in the radial direction, and includes an adjustment region for adjusting a distance from the center axis to the outer end. The ball screw device of claim 4, wherein the outer end portion is a protrusion. The ball screw device of claim 4, wherein the outer end portion is formed thicker than the other portion. The ball screw device according to any one of claims 4 to 6, further comprising a fixing member that fixes the ball circulation pipe to the nut. The ball screw device according to any one of claims 4 to 6, wherein the fixing member has a fixing portion that covers one of the ball circulation pipes from the outside in the radial direction, and is integrally formed with the fixing portion. The surface of the mounting portion of the cylindrical portion is formed on the radially outer surface of the fixing portion to form a curved surface that is disposed on the same cylindrical surface as the outer circumferential surface of the cylindrical portion.