JP2009036266A - Movement guiding device and screw device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movement guiding device equipped with a holder capable of corresponding to pulling, twisting, and bending in a plane surface including a coupling member, and a screw device. <P>SOLUTION: The holder has a plurality of spacers 17 interposed between rolling elements, and a pair of the coupling members 19 coupling the plurality of the spacers 17 in series. Each of the pair of coupling members 19 has a part coupling a pair of adjacent spacers 17, and a part which does not couple that. At a part where one coupling member 19 does not couple the pair of the adjacent spacers 17, the other coupling member 19 couples the pair of the adjacent spacers. At a part where the other coupling member 19 does not couple the pair of the adjacent spaces 17, one coupling member 19 couples the pair of the adjacent spacers. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motion guide device that guides a guide object such as a table to move linearly or in a curved manner, and a screw device in which a rolling element is interposed between a screw shaft and a nut so as to allow rolling motion.

  As a mechanical element for guiding a linear motion or a curved motion of a guide object such as a table, a motion guide device in which rolling elements such as balls and rollers are interposed in a guide portion is known. Since it can move lightly, it is used in various fields such as robots, machine tools, semiconductor / liquid crystal manufacturing equipment, and medical equipment.

  Also, a rolling element such as a ball or a roller is inserted between the spiral groove on the outer periphery of the screw shaft and the spiral groove on the inner periphery of the nut, and a return pipe or the like is inserted into the nut so that the rolling element can circulate. A ball screw provided with a circulation member is also known. Since the friction coefficient when rotating the screw shaft with respect to the nut can be reduced, it is used in various fields such as a feed mechanism of a machine tool, a positioning mechanism, a single-axis or multi-axis actuator, and an automobile steering.

  These motion guide devices and screw devices often incorporate a cage that keeps the spacing between the rolling elements. Since the metal contact between the rolling elements can be prevented, by incorporating the cage, effects such as quieter running noise, smooth movement of the moving block, and longer life are produced.

  As a cage incorporated in a motion guide device, Patent Document 1 discloses a cage in which a plurality of spacers 2 are interposed between balls 1 and a plurality of spacers 2 are connected by string members 3 as shown in FIG. Is disclosed. In this cage, the string-like member 3 is fitted into the notches 2 a formed at both ends in the width direction of the spacer 2.

In Patent Document 2, as shown in FIG. 11, a cage in which a plurality of spacers 4 are interposed between balls 1 and a plurality of spacers 4 are connected by a pair of connecting members 5 is interposed. In this cage, the pair of connecting members 5 are integrally molded with the spacer 4 by resin molding.
Japanese Patent Laid-Open No. 11-247855 Japanese Patent Laid-Open No. 10-238539

  FIG. 12 shows a cross-sectional view of the circulation path of the motion guide device. When the moving block 7 is slid with respect to the track rail 6, the ball 1 circulates in the circulation path. As the moving block slides, the ball 1 rolls while receiving a load on the loaded rolling element rolling path 8 between the track rail 6 and the moving block 7. On the other hand, in the no-load return passage 9, the ball 1 moves while being pushed by the subsequent ball 1. Since the speed of the ball 1 moving on the loaded rolling element rolling path 8 is slower than the speed of the ball 1 moving on the unloaded return path 9, the ball 1 moving on the loaded rolling element rolling path 8 and the unloaded return path 9 There is a speed difference with the ball 1 moving on the. Due to this speed difference, the ball 1 moving from the direction change path 10 to the load rolling element rolling path 8 is pulled by the string-like member 3 or the connecting member 5 of the cage.

  Further, as shown in FIG. 11, the cage moving in the circulation path is not only bent (M1) in a direction orthogonal to the plane P including the connecting member 5 (M1) but also twisted (T). 5 may be bent (M2) in the plane P including 5. For example, as shown in FIG. 13, when the cage is turned in a direction C2 inclined by an angle θ from a direction C1 orthogonal to the plane P including the connecting member 5, the cage is only bent in the direction C2. Not twisted. The circulation path of the screw device becomes a complicated circulation path in the three-dimensional space. The cage circulates while being twisted and being bent in a plane including the connecting member and in a direction perpendicular to the plane.

  That is, the cage moving in the circulation path is not only pulled but also circulated while being twisted and bent. In the cage described in Patent Document 1, since the string-like member 3 can slide with respect to the spacer 2, the tensile force applied to the string-like member 3 can be relaxed. However, it is difficult to cope with bending in a plane including twists and string-like members. Even in the cage described in Patent Document 2, it is difficult to cope with bending in a plane including a twist and a connecting member.

  Then, an object of this invention is to provide the exercise | movement guide apparatus and screw apparatus provided with the holder | retainer which can respond to the twist and the bending in the plane in which a string-like member or a connection member is included.

  The present invention will be described below. In addition, in order to make an understanding of this invention easy, the reference number of an accompanying drawing is attached in parenthesis writing, However, This invention is not limited to the form of illustration.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a track rail having a rolling element rolling part, a load rolling element rolling part facing the rolling element rolling part, and the load rolling element. In a motion guide device comprising: a moving block having a rolling element circulation path including a rolling part; a plurality of rolling elements arranged in the rolling element circulation path; and a cage that keeps intervals between the plurality of rolling elements.
The retainer includes a plurality of spacers interposed between rolling elements, and a pair of connecting members that connect the plurality of spacers in series, and each of the pair of connecting members includes a pair of adjacent ones. There are a portion that connects the spacers and a portion that is not connected, and one connecting member is a portion that does not connect a pair of adjacent spacers, the other connecting member connects a pair of adjacent spacers, and the other connecting member However, in the part which does not connect a pair of adjacent spacers, the one connecting member is a motion guide device for connecting a pair of adjacent spacers.

  According to a second aspect of the present invention, in the motion guide device according to the first aspect, each of the pair of connecting members includes a plurality of pin bodies, and each of the plurality of spacers corresponds to the pin body. The pin body can be slid in the length direction of the pin body and can be rotated around the pin body.

  According to a third aspect of the present invention, in the motion guide device according to the second aspect, a hook portion for preventing the spacer from coming out of the pin body is provided at both ends in the axial direction of the pin body. It is characterized by.

  According to a fourth aspect of the present invention, in the motion guide apparatus according to the second or third aspect, each of the plurality of pin bodies connects only a pair of adjacent spacers, and the pin body of the one connecting member. However, in the portion where the pair of adjacent spacers are not connected, the pin body of the other connecting member connects the pair of adjacent spacers, and the pin body of the other connecting member connects the pair of adjacent spacers. In the portion not to be used, the pin body of the one connecting member connects a pair of adjacent spacers.

  According to a fifth aspect of the present invention, in the motion guide device according to any one of the second to fourth aspects, each of the plurality of spacers contacts a pair of rolling elements adjacent to both end faces in the traveling direction. A main body portion having a curved concave portion and a pair of overhang portions projecting to the side surface of the main body portion, and an insertion hole into which the pin body is inserted is opened in the overhang portion of the spacer; The pin body is narrower than the diameter of the pin body, a slit connected to the insertion hole is opened, and the pin body can be inserted into the insertion hole through the slit.

  According to a sixth aspect of the present invention, in the motion guide apparatus according to the first aspect, the plurality of spacers and the pair of connecting members are made of resin and are integrally molded.

  The invention according to claim 7 has a screw shaft having a spiral rolling element rolling part on the outer peripheral surface, and a helical load rolling element rolling part facing the rolling element rolling part on the inner peripheral surface. And a nut having a rolling element circulation path including the loaded rolling element rolling part, a plurality of rolling elements arranged in the rolling element circulation path, and a cage that keeps a space between the plurality of rolling elements. In the screw device, the retainer includes a plurality of spacers interposed between rolling elements, and a pair of connecting members that connect the plurality of spacers in series, and each of the pair of connecting members includes: There are a portion that connects a pair of adjacent spacers and a portion that does not connect, and in a portion where one connecting member does not connect a pair of adjacent spacers, the other connecting member connects a pair of adjacent spacers, The other connecting member is an adjacent pair In the portion not connected to the spacer, it said that one coupling member is a screw device for connecting a pair of spacers adjacent.

  According to the first aspect of the present invention, since there is a cut portion in each of the pair of connecting members, a cage that can cope with twisting and bending in a plane including the pair of connecting members is obtained. Moreover, since the other connection member is connected in the part where one connection member is cut, the rolling elements can be connected in series.

  According to the invention described in claim 2, since the spacer can slide in the length direction with respect to the pin body, the tensile force applied to the connecting member when the rolling element transitions from the direction change path to the load rolling element rolling path. Can be relaxed. Further, since the spacer can rotate around the pin body, it can cope with twisting.

  According to the third aspect of the present invention, since the amount of movement of the spacer is limited by the flange of the pin body, it is possible to prevent the rolling elements inserted between the spacers from falling off the spacer.

  According to invention of Claim 4, it can respond by twisting or bending.

  According to the fifth aspect of the present invention, cages having different full lengths can be obtained using the spacers and pin bodies having the same shape. Further, since the pin body can be inserted into the insertion hole of the spacer from the slit of the spacer, the work of attaching the pin body to the spacer becomes easy.

  According to the sixth aspect of the present invention, the cage can be easily manufactured.

  According to the seventh aspect of the present invention, since there are cut portions in each of the pair of connecting members, a cage that can cope with twisting and bending in a plane including the pair of connecting members is obtained. Moreover, since the other connection member is connected in the part where one connection member is cut, the rolling elements can be connected in series.

  FIG. 1 shows a perspective view of a motion guide apparatus in a first embodiment of the present invention. The motion guide device includes a track rail 11 and a moving block 12 that slides along the track rail 11. The track rail 11 is attached to the base, and the moving block 12 is attached to the guidance target. Between the track rail 11 and the moving block 12, a ball 13 as a rolling element is interposed so as to be able to roll.

  The track rail 11 has a deformed cross section and is elongated and extends linearly. The material of the track rail 11 is steel such as carbon steel, chrome steel, or stainless steel. For example, two ball rolling grooves 11a extending in the longitudinal direction are processed as rolling element rolling portions at both left and right end portions of the upper surface of the track rail 11. For example, two ball rolling grooves 11 a extending in the longitudinal direction are processed as rolling element rolling portions also at the upper end portions of the left and right side surfaces of the track rail 11. In this embodiment, there are a total of four ball rolling grooves 11a. The cross-sectional shape of the ball rolling groove 11a is a circular arc groove shape made of a single arc or a Gothic arch groove shape made of two arcs. The number of strips of the ball rolling groove 11a, the contact angle between the ball rolling groove 11a and the ball 13, and the like are variously set according to the load of the motion guide device. Since the ball 13 rolls, the ball rolling groove 11a is processed to have a small surface roughness and a high strength. The track rail 11 is provided with a plurality of mounting holes for mounting the track rail 11 to the base.

  A moving block 12 is assembled to the track rail 11. The moving block 12 is formed in a bowl shape as a whole, and is made of a resin that is provided at each of the moving block main body 15 made of carbon steel, chrome steel, stainless steel, or the like, and both ends of the moving block main body 15 in the moving direction. End plate 14.

  The moving block main body 15 has a central portion 15 b that faces the upper surface of the track rail 11 and a pair of leg portions 15 c that face the left and right side surfaces of the track rail 11. A plurality of load ball rolling grooves 15 a facing the ball rolling grooves 11 a of the track rail 11 are formed in the moving block body 15 as load rolling element rolling portions. Since the ball 13 rolls, the loaded ball rolling groove 15a is processed so that the surface roughness is small and the strength is increased. The moving block body 15 is processed with a screw portion 15d for attaching a guide object.

  Further, the moving block body 15 is formed with a ball return passage 15e which is a rolling element return passage extending linearly in parallel with the load ball rolling groove 15a. Since the diameter of the ball return passage 15e is slightly larger than the diameter of the ball 13, the ball 13 does not receive a load in the ball return passage 15e and moves in the ball return passage 15e while being pushed by the subsequent ball 13. The load ball rolling groove 15a extending in parallel and the ball return passage 15e are connected by a U-shaped direction change path (see reference numeral 10 in FIG. 12). The inner peripheral side of the direction change path is formed in the moving block body 15. An outer peripheral side of the direction change path is formed on the end plate 14.

  The pair of end plates 14 are made of resin and attached to both end surfaces of the moving block body 15 in the moving direction.

  A plurality of balls 13 are arranged in a circuit-shaped ball circulation path which is a rolling element circulation path constituted by a loaded ball rolling groove 15a, a ball return path 15e, and a U-shaped direction change path. The plurality of balls 13 are kept at a constant interval by a belt-like cage 16. A guide groove for guiding the cage 16 is formed in the ball circulation path.

  When the moving block 12 is moved relative to the track rail 11, a plurality of balls 13 interposed between the ball rolling groove 11a of the track rail 11 and the loaded ball rolling groove 15a of the moving block 12 roll. Exercise. The ball 13 that has rolled to one end of the load ball rolling groove 15 a of the moving block 12 is scooped up into the direction change path of the end plate 14. The ball 13 whose traveling direction is reversed on the U-shaped direction changing path enters the ball return path 15e. In the ball return passage 15e, the ball 13 moves while being pushed by the subsequent ball 13. The ball 13 that has moved to the end of the ball return path 15e passes through the opposite direction change path and then enters between the track rail 11 and the moving block 12 again.

  FIG. 2 shows a perspective view of the cage 16. The cage 16 includes a plurality of spacers 17 interposed between the balls 13 and a pair of connecting members 19 that are provided on both sides in the width direction of the spacers 17 and connect the spacers 17. The plurality of spacers 17 are arranged in a line. Each of the pair of connecting members 19 includes a plurality of pin bodies 18. Each of the plurality of pin bodies 18 couples a pair of spacers 17 adjacent in the front-rear direction.

  4 and 5 show detailed views of the spacer 17. The spacer 17 includes a cylindrical main body portion 17a and a pair of projecting portions 17b projecting on both sides of the main body portion 17a. On both end faces in the traveling direction of the main body portion 17a, curved concave portions 17c made of spherical surfaces corresponding to the shape of the ball 13 are formed. The curvature radius of the spherical surface is slightly larger than the curvature radius of the ball 13. The overhang portion 17b is an elongated rectangular shape, and is integrally molded with the main body portion 17a. This overhang portion 17b is guided to the guide groove of the ball circulation path. An insertion hole 20 extending in the axial direction of the cylindrical spacer 17 is opened in the overhang portion 17b. The pin body 18 is inserted into the insertion hole 20. A slit 21 connected to the insertion hole 20 is formed in the overhang portion 17b. The width of the slit 21 is narrower than the diameter of the pin body 18. When the pin body 18 is inserted into the insertion hole 20, the slit 21 is deformed so as to allow the insertion of the pin body 18. When the pin body 18 is inserted into the insertion hole 20, the slit 21 is restored, and the pin body 18 is prevented from coming out of the insertion hole 20. A force for pulling out the pin body 18 in the longitudinal direction is applied to the pin body 18, but a force for removing the pin body 18 from the insertion hole 20 through the slit 21 is difficult to work. For this reason, it is sufficient to prevent the slit 21 from coming off using elastic deformation.

  FIG. 6 shows a detailed view of the pin body 18. The pin body 18 connects a pair of adjacent spacers 17. At both ends in the axial direction of the pin body 18, flanges 18 b that prevent the spacer 17 from coming off the pin body 18 are provided. The length of the pin body 18 in the axial direction is set longer than the length from end to end of the pair of spacers 17 with the ball 13 interposed therebetween. This is because the spacer 17 can slide in the axial direction with respect to the pin body 18. As shown in FIG. 7, the movable range of the spacer 17 is limited by the flange portion 18 b 1 of the one pin body 18 and the flange portion 18 b 2 of the other pin body 18. The spacer 17 can rotate around the pin body 18 with respect to the pin body 18. The material of the pin body 18 may be metal or resin. However, it is necessary to bend flexibly on the U-shaped direction change path.

  FIG. 3 is a detailed view of the cage 16 in which the spacer 17 is connected by the pin body 18. A pair of adjacent spacers 17 are connected by a pair of connecting members 19 (consisting of a plurality of pin bodies 18) provided on both sides of the spacer 17. Here, in order to easily understand the relationship between one connecting member 19 (shown on the upper side in the drawing) and the other connecting member 19 (shown on the lower side in the drawing), numbers (1 ) To (5) are attached. In the upper connecting member 19 in the figure, the pin body 18-1 connects the spacer (1) and the spacer (2), and the pin body 18-2 adjacent to the pin body 18-1 is the spacer (3) and the spacer. Connect (4). In the upper one connecting member 19 in the figure, the spacer (2) and the spacer (3) are not connected.

  In the other connecting member 19 on the lower side in the figure, the pin body 18-3 connects the spacer (2) and the spacer (3), and the pin body 18-4 adjacent to the pin body 18-3 is connected to the spacer (4). Connect the spacer (5). In the other connecting member 19, the spacer (1) and the spacer (2), and the spacer (3) and the spacer (4) are not connected.

  That is, each of the pair of connecting members 19 includes a portion that connects a pair of adjacent spacers 17 and a portion that does not connect. And in the part which one connection member 19 does not connect a pair of adjacent spacers 17, the other connection member 19 connects a pair of adjacent spacers 17, and the other connection member 19 connects a pair of adjacent spacers 17. In the portion not to be connected, one connecting member 19 connects a pair of adjacent spacers 17. If a portion where both the connecting members 19 do not connect the pair of spacers 17 is generated, the cage 16 is cut. If the pair of connecting members has such a relationship, the cage 16 connected in series even if it has an end can be obtained.

  The pin body 18 may connect three or four adjacent spacers 17. Even in this case, it is necessary to keep the above relationship. However, unlike the case where only the pair of spacers 17 adjacent to each other with the pin body 18 is connected, the pair of spacers 17 adjacent to the other connection member 19 is connected to the portion where the pair of spacers 17 adjacent to each other is connected. May be connected or may not be connected.

The cage 16 having the above configuration has the following effects.
When the ball 13 moves from the direction change path to the load ball rolling path, the tensile force applied to the connecting member 19 of the cage 16 can be reduced. The moving speed of the ball 13 on the load ball rolling path is larger than the moving speed of the ball 13 on the direction changing path (see FIG. 12). However, even if the speed of the ball 13 changes, the spacer 17 interposed between the balls 13 can slide with respect to the pin body 18, so that the tensile force Te (see FIG. 1) applied to the pin body 18 can be reduced. it can. In addition, since the balls 13 are moved in pairs by two pairs of balls, the balls 13 that try to pull the connecting member 19 (the balls 13 that cause the connecting member 19 to generate a tensile force Te) are also About two to three. That is, unlike the conventional cage 16, the entire ball 13 moving on the load ball rolling path does not pull the connecting member 19, so that the tensile force applied to the connecting member 19 can be reduced.

  Since the connecting member 19 is broken in some places and the spacer 17 can rotate with respect to the connecting member 19, the torsional force Tr applied to the pin body 18 can be reduced even if the cage 16 is twisted. For this reason, it can respond to the twisted circulation path.

  Since the connecting member 19 is broken in some places, the bending moment M applied to the pin body 18 can be reduced even if the cage 16 is bent in the plane including the connecting member 19. For this reason, it can respond to the curved circulation path.

  FIG. 8 shows another example of the cage 16. In the cage 25 of this example, the plurality of spacers 23 and the pair of connecting members 24 are integrally molded with resin. The spacer 23 has a substantially cylindrical shape, and has curved concave portions corresponding to the outer shape of the ball 13 on both end surfaces in the traveling direction. The pair of connecting members 24 are band-shaped and are disposed on both sides of the spacer 23 in the width direction. Each of the pair of connecting members 24 is cut at portions where the balls 13 are fitted. The cutting positions 24 a are provided corresponding to every other ball 13. In the portion where one connecting member 24 is cut, the other connecting member 24 is not cut. Even the cage of this embodiment can cope with a twisted circulation path or a curved circulation path.

  FIG. 9 shows a perspective view of a screw device according to an embodiment of the present invention. The screw device includes a screw shaft 31, a nut 32 fitted to the screw shaft 31, and a plurality of balls 33 that are rolling elements interposed between the screw shaft 31 and the nut 32. On the outer peripheral surface of the screw shaft 31, a spiral ball rolling groove 31a is formed as a rolling element rolling portion. On the inner peripheral surface of the nut 32, a spiral loaded ball rolling groove 32a is formed as a loaded rolling element rolling portion. A return pipe 34 is attached to the side surface of the nut 32 as a circulation member. The return pipe 34 is formed with a ball return passage that connects one end of the loaded ball rolling groove 32a and the other end before several turns. A ball circulation path is constituted by the loaded ball rolling groove 32 a of the nut 32 and the ball return path of the return pipe 34.

  The cages 16 and 25 shown in FIG. 2 or 8 are inserted into the ball circulation path. The ball circulation path of the screw device is a complicated path in a three-dimensional space. The cage 16 of this embodiment is suitable for the path of the screw device.

  The present invention is not limited to being embodied in the above-described embodiment, and can be variously modified without changing the gist of the present invention. For example, a roller may be used instead of a ball for a rolling element incorporated in a motion guide device or a screw device. A plurality of cages may be inserted in the circulation path instead of only one.

  In the above-described embodiment, an example in which a linear guide that guides a linear motion to be guided is used as the motion guide device. However, a curved motion guide device that guides a curved motion may be used, and a spline may be used. May be used.

1 is a perspective view (including a partial cross-sectional view) of a motion guide device according to an embodiment of the present invention. Perspective view of cage Detailed perspective view of cage Perspective view of spacer Front view of spacer Perspective view of pin body Diagram showing the movable range of the spacer Plan view showing another example of cage 1 is a perspective view (including a partial cross-sectional view) of a screw device according to an embodiment of the present invention. Side view showing a conventional cage The figure which shows the conventional holder | retainer ((a) in a figure shows a side view, (b) shows a top view in a figure). Sectional drawing which shows the circulation path of the conventional motion guide apparatus Sectional view in the direction perpendicular to the track rail of the conventional motion guide device

Explanation of symbols

11. Track rail 11a Ball rolling groove (rolling element rolling part)
12 ... Moving block 13 ... Ball (rolling element)
15a: Loaded ball rolling groove (loaded rolling element rolling part)
16, 25 ... Cage 17, 23 ... Spacer 17a ... Main body 17b ... Overhang 17c ... Curved recess 18 ... Pin body 18b ... Gutter 19, 24 ... Connecting member 20 ... Insertion hole 21 ... Slit 31 ... Screw shaft 31a ... Ball rolling groove (rolling element rolling part)
32 ... Nut 32a ... Loaded ball rolling groove (Loaded rolling element rolling part)
33 ... Ball (rolling element)

Claims (7)

A track rail having a rolling element rolling part, a moving block having a rolling element rolling path that includes the loaded rolling element rolling part, and a moving block having a loaded rolling element rolling part facing the rolling element rolling part, In a motion guide device comprising: a plurality of rolling elements arranged in a rolling element circulation path; and a retainer that maintains an interval between the plurality of rolling elements,
The cage is
A plurality of spacers interposed between the rolling elements, and a pair of connecting members for connecting the plurality of spacers in series,
Each of the pair of connecting members has a portion that connects a pair of adjacent spacers and a portion that does not connect,
In a portion where one connecting member does not connect a pair of adjacent spacers, the other connecting member connects a pair of adjacent spacers,
The motion guide device in which the one connecting member connects the adjacent pair of spacers at a portion where the other connecting member does not connect the adjacent pair of spacers. Each of the pair of connecting members is composed of a plurality of pin bodies,
2. The motion guide device according to claim 1, wherein each of the plurality of spacers is slidable in a length direction of the pin body with respect to the pin body and can rotate around the pin body.   The motion guide device according to claim 2, wherein a flange portion that prevents the spacer from coming off the pin body is provided at both end portions in the axial direction of the pin body. Each of the plurality of pin bodies connects only a pair of adjacent spacers,
In the portion where the pin body of the one connecting member does not connect the pair of adjacent spacers, the pin body of the other connecting member connects the pair of adjacent spacers,
The pin body of the other connecting member connects the adjacent pair of spacers at the portion where the pin body of the other connecting member does not connect the adjacent pair of spacers. 3. The exercise guide device according to 3. Each of the plurality of spacers has a main body portion having a pair of curved concave portions that come into contact with a pair of rolling elements adjacent to both end surfaces in the traveling direction, and a pair of overhang portions protruding from the side surfaces of the main body portion. And
In the protruding portion of the spacer, an insertion hole into which the pin body is inserted is opened, a width narrower than the diameter of the pin body, and a slit connected to the insertion hole is opened,
The motion guide device according to claim 2, wherein the pin body can be inserted into the insertion hole through the slit.   The motion guide device according to claim 1, wherein the plurality of spacers and the pair of connecting members are made of resin and are integrally molded. A screw shaft having a spiral rolling element rolling part on the outer peripheral surface, and a spiral load rolling element rolling part facing the rolling element rolling part on the inner peripheral surface, and the load rolling element rolling part In a screw device comprising: a nut having a rolling element circulation path including: a plurality of rolling elements arranged in the rolling element circulation path; and a cage that keeps a space between the plurality of rolling elements.
The cage is
A plurality of spacers interposed between the rolling elements, and a pair of connecting members for connecting the plurality of spacers in series,
Each of the pair of connecting members has a portion that connects a pair of adjacent spacers and a portion that does not connect,
In a portion where one connecting member does not connect a pair of adjacent spacers, the other connecting member connects a pair of adjacent spacers,
The screw device in which the one connecting member connects the adjacent pair of spacers at a portion where the other connecting member does not connect the adjacent pair of spacers.

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