KR102300419B1 - Ball Screw - Google Patents

Abstract

This ball screw is formed in a compact size by disposing a return plate 4 on the outer peripheral surface of the nut body 3, disposing the containing member 5 on the return plate 4, By lubricating the ball 9 to be lubricated, maintenance-free lubrication is realized. This ball screw is composed of a nut (2) fitted with a screw shaft (1), a nut body (3) having a spiral groove (12), and a return plate (4) disposed on the outer peripheral surface (27), The containing member 5 provided with the oil supply part 6 in the recessed part 28 of the plate 4 is arrange|positioned. The return path 13 formed by the nut body 3 and the return plate 4 and the ball 9 running the direction change path 14 of the nut body 3 are exposed at the exposed end surface 34 of the oil supply part 6, Lubricant is supplied to the ball (9) in contact with the 露出端面.

Description

Ball Screw

The present invention is, for example, used in various devices such as mechatronic products such as precision positioning tables, inspection devices, etc. ) to a ball screw with means.

DESCRIPTION OF RELATED ART Conventionally, the linear motion apparatus which supplies a lubricant stably by self-lubrication is disclosed by Unexamined-Japanese-Patent No. 2013-174255, for example. The linear actuator is an end deflecter type ball screw drive device, and includes a nut having a spiral groove formed on its inner peripheral surface, a screw shaft having a spiral groove opposite to the spiral groove of the nut formed on its outer peripheral surface, and a spiral groove of the nut. and a plurality of balls inserted between the spiral raceway surfaces formed by the spiral grooves of the screw shaft. The nut is formed with a return passage integrally injection-molded with a surface in the axial direction by an oleaginous resin material therein.

In addition, the present applicant has developed a rolling guide unit that has improved design freedom, is easy to manage lubricating oil, and has less sliding resistance with respect to rolling elements, and has previously applied for a patent (for example, Japanese Laid-Open Patent Application) See Patent Publication No. 2006-38195). The rolling guide unit has both ends of a tubular member through which the rail is freely slidable, a track formed by the tubular member and the rail together, and a raceway formed in the tubular member. It is provided with the circulation path in which the (兩端) was made to communicate through the recessed part of the direction change path, and the some rolling element which rotates the circulation path and the said track path. As for the said rolling guide unit, a rolling element circulates in a circulation path and a track path according to the relative movement of a rail and a cylinder member. The rolling guide unit includes an insertion hole formed in the cylinder member, a containment member inserted into the insertion hole, and an oil supply member provided along a contact surface of a rolling element in a raceway or circulation path, the oil The supply member is brought into contact with the containing member.

Further, as a roller screw, a return plate type circulating screw device is disclosed in, for example, Japanese Patent Laid-Open No. 11-210858. This circulation type screw device has a circulation structure of a power roller that is easy to manufacture and inexpensive while securing the characteristics of a low-friction mechanism equivalent to that of a ball screw. It communicates with both ends of the roller transmission part, and is provided with the roller lifting part of these both ends, and the roller circulation part which communicates them.

However, the linear actuator is one in which the nut and the nut are integrally molded by injection molding of an oleaginous resin material in the return passage of the nut. Since the resin material containing the resin material is pre-mixed with the lubricating oil and the mixed material is injection-molded, when the lubricating oil capacity is small, the lubricating oil cannot be replenished, and the lubrication is likely to be poor. There is a problem in that it is necessary to injection-mould the resin material-containing material integrally with the ? In addition, the rolling guide device realizes maintenance-free lubrication by providing an oil supply member in a direction change path of an end cap of a ball spline and a containment member in the outer cylinder. However, there was a problem in that the containing member was inserted into the insertion hole and the supply of lubricating oil from the containing member to the oil supply member was insufficient. Moreover, although the said circulation type screw device is comprised with the structure of the return plate type which circulates a rolling element, the rolling element is a roller, and the supply of lubricant is not performed by the return plate.

An object of the present invention is to solve the above problems, a screw shaft having a single row of spiral grooves is inserted into a nut having a single row of spiral grooves formed on the inner circumferential surface, and a spiral track formed between the two spiral grooves. A ball screw in which the nut moves relative to the screw shaft by interposing the ball of the rolling element in the furnace, and a return groove is formed on a flat surface formed on a part of the outer circumferential surface of the nut corresponding to the return path formed in the nut. A return plate is provided, the device itself is configured to be formed in a compact size in the longitudinal direction, and a containment member is arranged on the return plate without changing the outer shape of the ball screw, and the containment member By placing the oil supply part installed on the pole between the return groove and the direction change path, the ball that rolls the direction change path and the return path comes into contact with this oil supply part and supplies oil to the ball, so that the maintenance free (lubrication) It is to provide a ball screw that realizes maintenance free).

The present invention provides a rotatable screw shaft in which a first spiral groove in a row for rolling a plurality of rolling body balls is formed in an axial direction on an outer circumferential surface, and a second spiral groove in a row opposite to the first spiral groove is an inner circumferential surface has a cylindrical nut formed in the axial direction and threaded through the ball through the screw shaft, and in response to rotation of the screw shaft, the nut is rotated into the screw shaft Consists of moving the phase in the longitudinal direction,

The nut includes the second spiral groove formed on the inner circumferential surface, a first return groove formed on the outer circumferential surface through which the ball rolls, and a direction change in which the second spiral groove and the first return groove communicate with each other, respectively. A tubular nut body having a communication hole forming a furnace, a return plate fixed to an outer diameter side mounting surface of the nut body and provided with a second return groove opposite to the first return groove; It is composed of a containing member impregnated with a lubricant excreted in a recessed portion on the inner side of the return plate,

The containing member is disposed in a body portion impregnated with a lubricant disposed in the recessed portion of the return plate, and a communication groove communicating the recessed portion and the second return groove, and protrudes from the body portion to provide the second and an oil supply unit protruding into the return groove, and on an exposed end surface of the oil supply unit, an electric pole between the return groove formed by the first return groove and the second return groove and the direction change path It relates to a ball screw configured to contact the ball and supply the lubricant to the ball.

This ball screw is provided with the flange part in which the mounting hole for attaching a mating member was formed in the said nut body.

In this ball screw, the mounting surface on which the first return groove is formed of the nut body is formed in a rectangular plane, and the inner surface of the return plate opposite the installation surface is arranged in the rectangular plane. The nut has a substantially circular cylindrical body with the return plate disposed on the nut body, and the outer circumferential surface of the return plate has a circular cross-section. .

The first return groove and the second return groove are respectively formed to be inclined in the axial direction on the rectangular plane of the nut body and the return plate, and the first return groove and the second return groove The return path formed as a nut is in communication with the direction change path formed at each end of the second spiral groove that is spirally spread on the inner circumferential surface of the nut body.

Further, the ball screw is a spiral raceway in which the ball is formed by the first spiral groove of the screw shaft and the second spiral groove of the nut body corresponding to the rotation of the screw shaft, the track a circuit formed by a pair of the turning path formed in the nut body communicating with both ends of the furnace, respectively, and the return path communicating with the turning path, the nut is connected to the screw shaft The image is moved relative to the ball.

Further, in the containing member disposed in the concave portion of the return plate, an outer peripheral surface on the side of the return plate is formed on a circular arc surface in cross section, and an inner peripheral surface on the side of the nut body is flat. is being formed with

Further, in this ball screw, the second return groove is formed in the concave portion formed in the return plate, and the containing member disposed in the concave portion is formed as a one-piece, They communicate with the second return grooves through the communication grooves respectively formed at both ends of the wall portions forming the second return grooves. Alternatively, the concave portion formed in the return plate is divided into two in the longitudinal direction by a wall portion forming the second return groove as a boundary, and the containing member is provided in the two-piece concave portion, respectively. piece), and the oil supply part is formed in the containing member of the two-piece, respectively.

Moreover, the said screw shaft is a ball screw shaft of a round shaft type by which both ends were rotatably supported. Further, at both ends of the nut body, annular fitting portions for fitting a sealing ring for sealing a gap between the screw shaft and the nut are formed.

In addition, the containing member and the oil supply part press and harden the synthetic resin particles of polyethylene or polypropylene and heat-molding, and at the same time, the synthetic resin particles communicate with each other in a porous state. It is formed into a porous molded body provided with a part, and the said lubricating agent is impregnated in the said porous part.

The ball screw according to the present invention is configured as described above, a return plate forming a return path is disposed on the outer circumferential surface of the nut body, and the ball screw is formed in a compact size. Without changing the external shape of the screw, the containing member is disposed in the concave portion of the return plate, the direction change path connecting the spiral groove and the return path is formed by the nut body and the return plate, and is installed on the containing member An oil supply part is placed at the boundary between the nut body and the return plate, and the ball, a rolling element that runs between the direction change path and the return path, is brought into contact with the oil supply part to supply lubricant to the ball and improve lubrication. Realize maintenance free. In addition, this Ball Screw has a concave portion provided in the return plate to dispose the containing member, and a direction change path is provided in the nut body, so that the longitudinal direction can be shortened, and the lubricating member as in the prior art can be used. It does not require a holder part to accommodate it, and the stroke amount of the nut can be increased by its share, the number of parts can be reduced, contributing to cost reduction, and supporting and maintaining the lubricating plate as in the prior art The space for the holder is unnecessary, and the part can be attached to parts other than the lubricating member. In addition, since the return plate provided to the nut body is not fitted to the screw shaft, even after assembling the containing member, the containing member can be detached simply by removing the return plate from the nut body. It can also be easily replaced with a (new) containing member.

1 is a perspective view showing an embodiment of a ball screw according to the present invention.
Fig. 2 is a perspective view showing a part of the ball screw of Fig. 1 by breaking it;
FIG. 3 is a perspective view showing an embodiment of the containing member and the nut body in a state of being transmitted to explain the screw shaft and the return plate in the ball screw of FIG. 1 .
Fig. 4 is a diagram in which an oil-supplying member is disposed in a boundary region between a return path and a direction change path in a circulation path formed in a nut constituting the ball screw of Fig. 1, and It is a cross-sectional view showing the lubrication state of the
5 is a perspective view showing a state in which the containing member is disposed on the inner circumferential side of an embodiment of the return plate attached to the nut body constituting the ball screw of FIG. 1;
Fig. 6 is a perspective view showing the outer peripheral surface side of the containing member disposed in the concave portion of the return plate of Fig. 5;
Fig. 7 is a perspective view showing the inner peripheral surface side from which the containing member is removed from the return plate of Fig. 5;
FIG. 8 is a perspective view showing another embodiment showing the containing member and the nut body in a state of being transmitted through the ball screw of FIG. 1 to explain the screw shaft and the return plate.
Fig. 9 is a perspective view showing another embodiment in which an inclusion member is disposed in a concave portion of a return plate attached to a nut body constituting the ball screw of Fig. 1;
Fig. 10 is a perspective view showing the outer circumferential side of one of the two-piece containing members disposed in the concave portion of the return plate of Fig. 9;
Fig. 11 is a perspective view showing the outer circumferential side of the other two-piece containing member disposed in the concave portion of the return plate of Fig. 9;
Fig. 12 is a perspective view showing the inner peripheral surface side from which the containing member is removed from the return plate of Fig. 9;

The ball screw according to the present invention is suitable for application to various devices such as mechatronic products such as precision positioning tables and inspection devices.

Hereinafter, an embodiment of the ball screw according to the present invention will be described with reference to the drawings. First, an embodiment of a ball screw according to the present invention will be described with reference to FIGS. 1 to 7 . This ball screw is a rotatable screw shaft (1) in which a row of spiral grooves (11, first spiral grooves) in which a plurality of rolling body balls (9) roll are formed in the axial direction on the outer peripheral surface (10). 1) and a row of spiral grooves 12 (second spiral grooves) opposite to the spiral groove 11 are formed in the axial direction on the inner circumferential surface 17 (FIG. 2), and at the same time, the screw shaft 1 is connected to the rolling chain. It has a tubular nut (2) that is screwed in and inserted through a ball (9), and the return consisting of the nut (2) moving longitudinally on the screw shaft (1) in response to the rotation of the screw shaft (1) It is made of plate type. The nut 2 includes a row of spiral grooves 12 formed on the inner peripheral surface 17, a return groove 29 (first return groove) and a spiral groove (first return groove) through which the balls 9 formed on the outer peripheral surface 27 run. The nut body 3 and the nut body 3 in the shape of a cylinder in which a communication hole 41 (連通孔) is formed to form a direction change path 14 for communicating the 12) and the return groove 29, respectively. ), a return plate 4 having a return groove 30 (second return groove) opposite to the return groove 29 while being fixed to the attachment surface 21 formed on the outer peripheral surface 27 of the outer diameter side, and the return plate 4 . The spiral raceway 15 is formed by matching the spiral groove 11 of the screw shaft 1 and the spiral groove 12 of the nut body 3 to each other. Further, the return path 13 is formed by matching the return groove 29 of the nut body 3 and the return groove 30 of the return plate 4 . The spiral upper orbital road 15 and the return groove 13 are communicated with each other by a direction change path 14 made of a communication hole 41 formed in the nut body 3, have.

Further, the screw shaft 1 is a ball screw shaft 1 of a round shaft type in which both ends 26 are rotatably supported. Further, at both ends 18 of the nut body 3, annular fitting portions 40 are formed, and in the annular fitting portion 40, the screw shaft 1 and In order to seal the gap with the nut (2), a sealing ring (19, sealing ring) formed on the inner circumferential surface with a groove (47) to fit into the spiral groove (11) of the screw shaft (1) is fitted. The return plate (4) has an attachment hole (44) formed in its boss portion (45), and a set screw (31) is inserted into the attachment hole (44) to pass through the attachment surface ( 21), the return plate 4 is fixed to the nut body 3. The periphery of the return groove 30 formed in the return plate 4 protrudes from the recessed portion 28. It is formed by the wall part 32 for partitioning, in other words, the return groove 30 is formed in the recessed part 28 formed in the return plate 4. The containing member provided in this recessed part 28. 5 is formed in a one-piece shape.In the wall portion 32 of the return plate 4, a communication groove 24 into which the oil supply portion 6 is fitted is provided. It is formed toward 30. Further, in the nut body 3, a fitting hole 33 in the inner circumferential surface 17 to be fitted to the screw shaft 1 is formed, and the fitting hole 33, The ball 9 intervenes in the spiral raceway 15 formed by the spiral groove 12 formed in the shaft 1 and the spiral groove 11 of the screw shaft 1, and the nut The screw shaft 1 is threaded through the main body 3 .

The containing member 5 includes a body portion 42 impregnated with a lubricant and a pair of oil supply portions 6 protruding from the body portion 42 . The body portion 42 of the containing member 5 is disposed in the concave portion 28 of the return plate 4 , and the oil supply portion 6 is disposed in the concave portion 28 of the return plate 4 . and the return groove 30 are excreted in the communication groove 24 for communicating (連通). The oil supply part 6 disposed in the communication groove 24 is configured such that its exposed end face 34 protrudes from the return groove 30 and comes into contact with the ball 9 for transporting the return passage 13 , have. In the body portion 42 of the containing member 5, the region where the return groove 30 is formed is formed in an elongated hole 36, and the return groove of the return plate 4 is formed in the elongated hole 36. The wall part 32 forming the 30 is comprised so that it may fit. The containing member 5 is formed with a recessed portion 35 into which the boss portion 45 of the return plate 4 is fitted. When the containing member 5 is disposed in the concave portion 28 of the return plate 4 , the long hole 36 of the containing member 5 constitutes the return groove 30 of the return plate 4 . It surrounds the wall part 32 and is fitted. In a state in which the boss portion 45 of the return plate 4 is fitted into the recessed portion 35 of the containing member 5 , the body portion 42 of the containing member 5 is inserted into the recessed portion of the return plate 4 . (28) is excreted. In other words, the oil supply part 6 provided in the recessed part 28 of the return plate 4 is attached to the nut body 3 with the attachment surface 21 of the nut body 3 and the return plate ( 4) is located between the inner surface 22 and. The exposed end face (34) of the oil supply part (6) is exposed to the return path (13) in a state where it is disposed and attached to the communication groove (24), and the return groove (29) and the return groove (30) A ball 9 that rolls between the return path 13 and the direction change path 14 formed by .

Further, the nut body 3 is provided with a flange 20 in which an attachment hole 25 for attaching a counterpart member such as a work or equipment is formed. In addition, the attachment surface 21 formed on the outer peripheral surface 27 of the nut body 3 has a rectangular flat surface, and a row of return grooves 29 are formed. The inner surface 22 of the return plate 4 is formed in a rectangular flat surface disposed on the attachment surface 21 of the rectangular flat surface, and the containing member ( 5) is formed. The outer peripheral surface 23 of the return plate 4 is formed in a circular cross-section, and in a state in which the return plate 4 is disposed on the nut body 3, the nut 2 has a substantially circular cylindrical body. body) is formed.

In this ball screw, the return groove 29 formed in the nut body 3 and the return groove 30 formed in the return plate 4 are formed on a rectangular plane between the nut body 3 and the return plate 4 in the axial direction. That is, each is inclined in the longitudinal direction, and the return path 13 formed of the return groove 29 and the return groove 30 is a spiral groove ( 12), respectively, communicate with a direction change path 14, which is a pair of communication holes 42 formed at both ends, respectively.

In addition, in response to the rotation of the screw shaft 1, the ball 9 is a spiral track 15 formed of the spiral groove 11 of the screw shaft 1 and the spiral groove 12 of the nut body 3, A direction change path 14 that is a pair of communication holes 41 formed in the nut body 3 communicating with both ends of the track path 15, respectively, and a return path 13 communicating with the direction change path 14 The circulation path 16 formed by

In addition, in the containing member 5 disposed in the recessed portion 28 of the return plate 4, the outer surface 43 on the return plate 4 side is formed in an arc cross-section, and at the same time, the nut The inner surface 39 on the main body 3 side is formed in a plane. In this embodiment, a one-piece containing member 5 is disposed in the recessed portion 28 formed in the return plate 4 . The return groove (30) formed in the return plate (4) is disposed to face the return groove (29) formed in the nut body (3) to form a return path (13). In addition, in this ball screw, the containing member 5 and the oil supply part 6 press and harden the synthetic resin particles of polyethylene or polypropylene and heat-molding, and at the same time, the synthetic resin particles communicate with each other. It is formed into a porous molded body having porous portions maintained in a state of shape, and the porous portions are impregnated with the lubricant. Therefore, in this ball screw, the return path 13 is formed by the return plate 4 and the outer peripheral surface 27 of the nut body 3, so that the ball 9 running around the return path 13 is In contact with the end face 34 exposed to the return path 13 from the communication groove 24 of the concave portion 28 of the plate 4 , the containing member 5 and the oil supply portion 6 are embedded with chips. ) in which the lubricant is supplied to the ball 9, it is possible to achieve maintenance-free lubrication. In addition, with respect to the ball screw, a ball screw drive, for example, the shaft diameter (軸徑) of the screw shaft 1 is formed with a ф 6, formed on the outer peripheral surface 10 of the screw shaft (1), the helical groove ( 11) may be formed in a single row, and the lead may be formed to be 1 mm.

Next, another embodiment of the ball screw according to the present invention will be described with reference to FIGS. 8 to 12 . In the second embodiment, the containing member 7 is formed as a two-piece containing member 7A, 7B, whereas the containing member 5 of the first embodiment is formed as a one-piece. Since they have the same structure except that they are formed, the same code|symbol is attached|subjected to the same member, and these description is abbreviate|omitted. The ball screw of the second embodiment has a two-piece shape in order to impregnate the containing members 7A and 7B provided in the recessed portion 28T of the return plate 4 with a large amount of lubricant. is formed That is, the containing members 7A and 7B provided in the recessed portion 28T of the return plate 4 are impregnated with a large amount of lubricant compared with the first embodiment, and the containing member 7 is It is divided into two in the longitudinal direction. In other words, in the containing members 7A and 7B disclosed in the second embodiment, compared with the containing member 7 disclosed in the first embodiment, the amount of the lubricant to be impregnated is large. Correspondingly, the recessed portion 28T formed in the return plate 4 is divided into two in the longitudinal direction with the wall portion 32 forming the return groove 30 as a boundary, and the containing member 7 is accompanied by this. ) is formed of two-piece containing members 7A and 7B. In addition, the return plate 4 has an end opposite to the flange portion 20 to prevent protrusion from the end portion of the containing member 7A disposed in the concave portion 28T. It is formed in the end partition wall 46 for preventing. An oil supply part 8 is formed in each of the pair of containing members 7A and 7B. Further, in this ball screw, the containing members 7A and 7B and the oil supply part 8 are heat-molded by pressing and hardening the fine synthetic resin particles of polyethylene or polypropylene, similarly to the first embodiment. At the same time, it is formed into a porous molded body having porous portions in which the shape of the synthetic resin fine particles are kept in communication with each other, and the lubricant is impregnated into the porous portions. Therefore, in this ball screw, since the return path 13 is formed by the return plate 4 and the outer peripheral surface 27 of the nut body 3, the ball 9 ) is in contact with the end face 34 exposed to the return path 13 from the communication groove 24 of the concave portion 28T of the return plate 4, and the containing members 7A and 7B and the oil supply portion ( The lubricant impregnated in 8) is supplied to the ball 9, so that maintenance free of lubrication can be achieved. In addition, with respect to this ball screw, the ball screw specification is, for example, the shaft diameter of the screw shaft 1 is formed by ф 8, and a spiral groove ( 11) may be formed in a single row, and the lead may be formed to be 2 mm.

1 screw shaft
2 nuts
3 Nut body
4 return plate
5 Inclusion member (含油部材, one-piece)
6 Oil supply part (for one-piece)
7 (7A, 7B) containing member (two-piece)
8 Oil supply (for two-piece)
9 Ball (rolling body: moving body)
10 Outer circumference (screw shaft)
11 Spiral groove (1st spiral groove, screw shaft)
12 Spiral groove (2nd spiral groove, nut body)
13 Return furnace (nut body)
14 end cap
15 Spiral Orbital Road
16 Ring Road
17 Inner peripheral surface (nut body)
18 End (端部: nut body)
19 Sealing ring (sealing ring: located on both ends of the nut body)
20 Flange part (flange part: nut body)
21 Mounting surface (nut body)
22 Inner side (內側面: return plate)
23 Outer periphery (return plate)
24 Communication groove (return plate)
25 Mounting hole (flange part)
26 End (端部: screw shaft)
27 Outer surface (outer surface: nut body)
28 Concave (one-piece, return plate)
28T concave part (two-piece, return plate)
29 1st return groove (nut body)
30 2nd return groove (return plate)
31 Fixing screw (fixing the nut body and return plate)
32 Wall member (return plate)
33 Fitting hole (嵌揷孔: nut body)
34 Exposed section
35 Concave part
36 Long hole
37 End (端部: 2nd spiral groove)
38 end (端部: spiral track)
39 Inner (內面: no containing)
40 Annular fitting part (For fitting end of nut body, sealing ring)
41 communication hole (連通孔: nut body)
42 Main body (main body: containing member)
43 Outer surface (outer surface: containing member)
44 Mounting hole (return plate)
45 Boss (return plate)
46 End partition wall (return plate, two-piece)
47 groove (溝: sealing ring)

Claims (11)

A rotatable screw shaft having a first helical groove in a row in which a plurality of rolling body balls roll is formed in the axial direction on an outer circumferential surface, and a second helical groove in a row opposite to the first helical groove are formed on the inner circumferential surface A ball formed in the axial direction and having a cylindrical nut in which the screw shaft is inserted through a rolling element ball, wherein the nut moves along the screw shaft in the longitudinal direction in response to the rotation of the screw shaft in the screw,
The nut may include the second spiral groove formed on the inner circumferential surface, a first return groove formed on the outer circumferential surface through which the ball rolls, and a direction change path that communicates the second spiral groove and the first return groove, respectively. A tubular nut body having a communication hole for forming a nut body, a return plate fixed to an attachment surface on the outer diameter side of the nut body and having a second return groove facing the first return groove, and an inner side of the return plate It is composed of an inclusion member impregnated with lubricant excreted in the recess.
In the containing member, an outer surface on the side of the return plate is formed to have a circular arc surface in cross section, and an inner surface on the side of the nut body is formed to be flat, and the lubricant is disposed in the recess of the return plate. a body portion impregnated with , and an oil supply portion disposed in a communication groove communicating the concave portion and the second return groove, and protruding from the main body portion to the second return groove,
On the exposed end face of the oil supply part, the ball that rolls between the return path formed by the first return groove and the second return groove and the direction change path is in contact with each other. A ball screw, characterized in that the lubricant is supplied to the ball. The method according to claim 1,
A ball screw comprising a flange portion provided with an attachment hole for attaching a mating member to the nut body. The method according to claim 1,
The attachment surface on which the first return groove is formed of the nut body is formed in a rectangular plane, and the inner surface of the return plate opposite the attachment surface is a rectangular plane arranged in the rectangular plane. is formed, and the outer circumferential surface of the return plate is formed in a circular cross-section, and in a state in which the return plate is disposed on the nut body, the nut has a substantially circular cylindrical body ( A ball screw that is formed from a single body. 4. The method according to claim 3,
The first return groove and the second return groove are respectively formed to be inclined in the axial direction on the rectangular plane between the nut body and the return plate, and form the first return groove and the second return groove. The formed return path is configured to communicate with the direction change path formed at each end of the second spiral groove that is spirally extended to the inner circumferential surface of the nut body. 5. The method according to claim 4,
Corresponding to the rotation of the screw shaft, the ball communicates with a spiral raceway formed by the first spiral groove of the screw shaft and the second spiral groove of the nut body, and both ends of the track passage, respectively. and a circulation path formed by a pair of the turning path formed in the nut body and the return path communicating with the turning path, and the nut passes on the screw shaft through the ball A ball screw made by relative movement. The method according to claim 1,
The second return groove is formed in the concave portion formed in the return plate, and the containing member disposed in the concave portion is formed as a one-piece and a wall portion forming the second return groove. ) in communication with the second return groove through the communication grooves respectively formed on both ends of the ball screw. The method according to claim 1,
The concave portion formed in the return plate is divided into two in the longitudinal direction by a wall portion forming the second return groove as a boundary, and the containing member is provided in the two-piece concave portion, respectively. is formed, and the oil supply part is formed on the two-piece containing member, respectively. The method according to claim 1,
The screw shaft is a ball screw shaft of a round shaft type in which both ends are rotatably supported. The method according to claim 1,
and annular fitting portions for fitting sealing rings for sealing a gap between the screw shaft and the nut are formed at both ends of the nut body. The method according to claim 1,
The containing member and the oil supply part are heat-molded by pressing and hardening the synthetic resin particles of polyethylene or polypropylene, and a porous part having a shape maintained between the synthetic resin particles in a communication state. A ball screw comprising a molded body and impregnated with the lubricant in the porous portion. delete

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