Motion guide device

Abstract

Provided is a motion guide device capable of inhibiting opening of a sleeve part of a lid member. A pair of lid members (5) of this motion guide device are caught by a restraining member having a joining part (9a) and a pair of bent parts (9b). The bent parts (9b) of the restraining member enter grooves (11) formed in end surfaces (5b) of the lid members (5). The joining part (9a) of the restraining member is brought into contact with side surfaces (5c) of sleeve parts (5-2) of the lid members (5) opposing side surfaces of a rail (1). The bent parts (9b) are in a state of being elastically deformed in the grooves (11) so that the joining part (9a) presses the side surfaces (5c) of the sleeve parts (5-2).

Description

Movement guide device

[0001] The present invention relates to a motion guide device in which a carriage is guided by a rail via at least one rolling element.

[0002] A motion guide device is known that includes a rail with a rolling groove formed therein and a carriage that is guided by the rail via at least one rolling element (see Patent Document 1). The carriage includes a carriage body with a rolling groove formed therein and a pair of cover members that are provided at both ends of the carriage body and that form the outer periphery of a turning path.

[0003] The carriage has a generally inverted U-shape when viewed in the longitudinal direction of the rail, and has a central portion facing the top surface of the rail and a pair of sleeve portions facing the side surfaces of the rail. When the carriage moves relative to the rail, the rolling elements roll between the rail and the carriage, circulating in the carriage's circulation path.

[0004] JP 2019-190660 A

[0005] In recent years, for example, when used in semiconductor manufacturing equipment, carriages of motion guide devices are required to move at higher speeds and with higher acceleration / deceleration. However, when a carriage is moved at high speeds and with high acceleration / deceleration, the rolling elements collide with the sleeves of the cover member at high speeds and with high acceleration / deceleration. Because the sleeves of the cover member are cantilevered, with a fixed upper end and a free lower end, when the rolling elements collide with the sleeves at high speeds and with high acceleration / deceleration, the sleeves deform and open. This deformation of the sleeves generates large localized stresses in the sleeves, reducing their durability against repeated use.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a motion guide device that can suppress the opening of the sleeve portion of the lid member.

[0007] In order to solve the above problem, one aspect of the present invention is a motion guide device comprising a rail on which a rolling groove is formed, and a carriage guided on the rail via at least one rolling element, wherein the carriage comprises a carriage body on which a rolling groove is formed, and a pair of cover members provided at both ends of the carriage body and on which the outer periphery of a turning path is formed, the pair of cover members being sandwiched between restraining members having a joint and a pair of bent portions, the bent portions of the restraining member entering a groove formed on the end face of the cover member, the joint of the restraining member contacting the side of a sleeve portion of the cover member facing the side of the rail, and the bent portions being in a state of elastic deformed within the groove so that the joint presses against the side of the sleeve portion.

[0008] According to the present invention, the restraining member prevents the sleeve portion of the lid member from opening, thereby improving the durability of the sleeve portion of the lid member against repeated use.

[0009] FIG. 3( a ) is a perspective view of a motion guide device according to one embodiment of the present invention; FIG. 3( b ) is a perspective view of a cover member and an R-piece portion attached to the cover member; FIG. 3( a ) is a perspective view of a restraining member, and FIG. 3( b ) is a perspective view of the underside of a carriage to which the restraining member is attached; FIG. 3( a ) is a front view of a motion guide device according to this embodiment; FIG. 5( a ) is an enlarged view of part a in FIG. 5( b ), and FIG. 5( b ) is a perspective view of the cover member and the restraining member; and FIG. 5( b ) is a rear view showing a state in which a ball has collided with the sleeve portion of the cover member.

[0010] The motion guide device of the present invention will be described below with reference to the accompanying drawings. However, the motion guide device of the present invention can be embodied in various forms and is not limited to the embodiments described herein. The present embodiments are provided with the intention that those skilled in the art will be able to fully understand the invention by fully disclosing the specification.

[0011] 1 shows a perspective view of a motion guide device 10 according to one embodiment of the present invention. The motion guide device 10 according to this embodiment relates to a small-sized motion guide device known as a miniature guide, but is not limited to this.

[0012] The motion guide device 10 of this embodiment comprises a rail 1 and a carriage 2. The rail 1 is attached to a base or the like (not shown). The carriage 2 is attached to a table or the like (not shown). A plurality of balls 3 serving as rolling elements are interposed between the rail 1 and the carriage 2. The carriage 2 is guided by the rail 1 and is movable relative to the rail 1. When the carriage 2 moves relative to the rail 1, the balls 3 roll between them. Reference numeral 6 denotes a sealing member for sealing the inside of the carriage 2. In FIG. 1, the sealing member 6 is indicated by a two-dot chain line to show the end face of the cover member.

[0013] For ease of explanation, the configuration of the motion guide device 10 will be described below using the directions when the motion guide device 10 placed on a horizontal plane is viewed from the length direction of the rail 1, that is, the up / down, left / right, and front / rear directions in Figures 1 and 3. Of course, the placement of the motion guide device 10 is not limited to this.

[0014] As shown in FIG. 1 , a mounting hole 1c is formed on the top surface of the rail 1 for mounting the rail 1 to a base or the like. Two rolling grooves 1a, one above the other, are formed on each of the left and right side surfaces of the rail 1. A protrusion 1b is formed on each of the left and right side surfaces of the rail 1. The two rolling grooves 1a are formed above and below the protrusion 1b. Each rolling groove 1a is a circular arc groove. Note that the number, arrangement, and cross-sectional shape of the rolling grooves 1a formed on the rail 1 are not limited to those described above; for example, one rolling groove may be formed on each of the left and right side surfaces of the rail 1, and the rolling groove may be formed as a Gothic arch groove.

[0015] The carriage 2 comprises a carriage body 4 and a pair of cover members 5 provided at both ends of the carriage body 4. Two circulation paths 7, one above the other, are provided on each of the left and right sides of the carriage 2. Each circulation path 7 includes a rolling path C1 between the rolling groove 1a of the rail 1 and the rolling groove 4a of the carriage body 4 (see FIG. 3(b)), a substantially U-shaped turning path C2 provided in the carriage 2, and a return path C3 provided in the carriage 2. A plurality of balls 3 are arranged in the circulation paths 7.

[0016] The carriage body 4 has a central portion 4-1 facing the upper surface of the rail 1, and a pair of left and right sleeve portions 4-2 facing the side surfaces of the rail 1. Mounting holes 4b are formed on the upper surface of the carriage body 4 for attaching the carriage 2 to a table or the like. Two upper and lower rolling grooves 4a are formed in each of the left and right sleeve portions 4-2 of the carriage body 4, along which the balls 3 roll (see Figure 3(b)). Each rolling groove 4a is a circular arc groove. A return path C3 is formed in each of the left and right sleeve portions 4-2 of the carriage body 4, parallel to the rolling grooves 4a.

[0017] The number, arrangement, and cross-sectional shape of the rolling grooves formed in the carriage body 4 are not limited to those described above, and for example, one rolling groove may be formed in each of the left and right sleeves 4-2 of the carriage body 4, and the rolling groove may be formed as a Gothic arch groove. Also, the return path may be formed in the carriage body 4, or may be formed in a return path component attached to the carriage body 4.

[0018] 1, the cover member 5 has a central portion 5-1 facing the upper surface of the rail 1, and a pair of left and right sleeve portions 5-2 facing the left and right side surfaces of the rail 1. The central portion 5-1 of the cover member 5 is formed with a through-hole 5a through which a fastening member such as a screw passes to attach the cover member 5 to the carriage body 4. The left and right sleeve portions 5-2 of the cover member 5 each have the outer periphery of two upper and lower turning paths C2.

[0019] As shown in Figure 2, a recess 5d is formed in each of the left and right sleeves 5-2 of the cover member 5. A roughly semi-cylindrical R-piece part 8 is attached to this recess 5d. The inner periphery of two upper and lower turning paths C2 is formed on the outer periphery of the R-piece part 8. An inner plate (not shown) may be attached to the end face of the carriage body 4, and the R-piece part 8 may be formed integrally with the inner plate.

[0020] As shown in Figure 3(b), the pair of cover members 5 are sandwiched between restraining members 9. The restraining members 9 prevent each cover member 5 from opening in two directions. That is, the restraining members 9 prevent the cover members 5 from opening in the longitudinal direction of the rail 1, and also prevent the sleeve portions 5-2 of the cover members 5 from opening in a plane perpendicular to the longitudinal direction of the rail 1, as shown in Figure 6. The latter prevention of the opening of the sleeve portions 5-2 of the cover members 5 is a feature of the motion guide device 10 of this embodiment.

[0021] As shown in FIG. 3( a), the restraining member 9 is wire-shaped and has a substantially rectangular cross section. The material of the restraining member 9 is not particularly limited, but steel with a high Young's modulus is desirable. The restraining member 9 has a joint 9a and a pair of bent portions 9b. The joint 9a extends linearly in the longitudinal direction of the rail 1. The bent portions 9b bend relative to the joint 9a. As shown in FIG. 3( b), a groove 11 is formed on the end surface 5b of the cover member 5. The bent portion 9b of the restraining member 9 fits into the groove 11. The joint 9a of the restraining member 9 contacts the side surface 5c of the sleeve portion 5-2 of the cover member 5 that faces the side surface of the rail 1.

[0022] As shown in the front view of the motion guide device in Figure 4, the joint 9a of the restraint member 9 contacts the side surface 5c of the sleeve portion 5-2 below the lower ball row 21b of the two upper and lower ball rows 21a, 21b arranged between the rolling groove 1a on the side surface of the rail 1 and the rolling groove 4a of the carriage body 4. This is to effectively prevent the sleeve portion 5-2 from opening. If a single ball row is arranged between the rolling groove 1a on the side surface of the rail 1 and the rolling groove 4a of the carriage body 4, the joint 9a only needs to contact the side surface 5c of the sleeve portion 5-2 below the single ball row.

[0023] The joint 9a is preferably in contact with the inclined surface 5c1 at the lower end of the sleeve 5-2. This inclined surface 5c1 is inclined relative to the lower end surface 5e of the sleeve 5-2 so as to approach the center line 1d of the rail 1 as it goes upward.

[0024] 6, in order to prevent the sleeve portion 5-2 of the cover member 5 from opening, the joint portion 9a of the restraint member 9 needs to press against the inclined surface 5c1 of the sleeve portion 5-2. The bent portion 9b is in an elastically deformed state within the groove 11 so that the joint portion 9a presses against the inclined surface 5c1 of the sleeve portion 5-2.

[0025] As shown in FIG. 4 , the bent portion 9b is bent in two stages. The bent portion 9b has a root portion 9b1, an intermediate portion 9b2, and a tip portion 9b3. The root portion 9b1, the intermediate portion 9b2, and the tip portion 9b3 are substantially linear. The root portion 9b1 extends in a direction substantially perpendicular to the inclined surface 5c1. The intermediate portion 9b2 is bent relative to the root portion 9b1. The tip portion 9b3 is bent relative to the intermediate portion 9b2. Note that the bent portion 9b may be composed of the root portion 9b1 and the tip portion 9b3, and bent in a single stage.

[0026] The groove 11 on the end surface 5b of the cover member 5 has a root groove 11a into which the root portion 9b1 of the bent portion 9b fits, an intermediate groove 11b into which the intermediate portion 9b2 of the bent portion 9b fits, and a tip groove 11c into which the tip portion 9b3 of the bent portion 9b fits. By forming the intermediate groove 11b, it is possible to prevent interference between the groove 11 formed on the front side of the cover member 5 and the upper turning path C2 formed on the rear side of the cover member 5 in a front view of the motion guide device 10. Note that the groove 11 of the cover member 5 may be composed of the root groove 11a and the tip groove 11c, and the groove 11 may be bent in a single stage.

[0027] When the bent portion 9b of the restraining member 9 is protruding from the groove 11 of the cover member 5, the angle formed by the base portion 9b1 and the tip portion 9b3 of the restraining member 9 is set to be smaller than the angle θ formed by the base groove 11a and the tip groove 11c of the cover member 5. Therefore, the bent portion 9b of the restraining member 9 enters the groove 11 of the cover member 5 with the base portion 9b1 and the tip portion 9b3 open and elastically deformed. The tip portion 9b3 of the restraining member 9 contacts the wall surface of the tip groove 11c of the groove 11, and the spring force of the tip portion 9b3 of the restraining member 9 is mainly used to press the joint portion 9a against the inclined surface 5c1 of the cover member 5. The angle θ formed by the base groove 11a and the tip groove 11c is set to be 90° or less, preferably an acute angle. This increases the force with which the joint 9a of the restraining member 9 presses against the side surface 5c of the sleeve portion 5-2, thereby making it possible to more effectively prevent the restraining member 9 from falling off.

[0028] 4, the width W1 of a portion of the base groove 11a of the cover member 5 is narrower than the width W2 of the intermediate groove 11b and the tip groove 11c. In other words, the clearance in the portion of the base groove 11a is smaller than the clearance in the intermediate groove 11b and the tip groove 11c. This allows the base portion 9b1 of the bent portion 9b to be fixed so as not to move, and prevents the entire bent portion 9b from shifting within the groove 11 of the cover member 5.

[0029] When the carriage 2 is moved at high speed and with high acceleration and deceleration, the ball 3 collides with the scoop portion 12 of the lower turning path C2 of the sleeve portion 5-2 of the cover member 5, as shown in FIG. 6 . The sleeve portion 5-2 is a cantilever beam with a fixed upper end and a free lower end. When the ball 3 collides with the scoop portion 12, a force P acts from the ball 3 on the sleeve portion 5-2 in an opening direction, causing the sleeve portion 5-2 to open. When the sleeve portion 5-2 opens, large localized stress is generated in the sleeve portion 5-2, reducing the repeated use durability of the sleeve portion 5-2. Note that the ball also collides with the scoop portion on the upper turning path C2, but because the scoop portion of the upper turning path C2 is close to the fixed end, the sleeve portion 5-2 does not open substantially even if the ball collides with the scoop portion on the upper turning path C2.

[0030] As shown in Figure 6, in this embodiment, the joint 9a of the restraining member 9 presses against the inclined surface 5c1 of the sleeve portion 5-2 of the cover member 5, and the restraining member 9 prevents the sleeve portion 5-2 from opening. This distributes locally generated stress, improving the repeated use durability of the sleeve portion 5-2. The distribution of locally generated stress has been confirmed by both FEM analysis and testing.

[0031] The effects of the motion guide device 10 of this embodiment will be described below: Since the restraining member 9 prevents the sleeve portion 5-2 of the cover member 5 from opening, the repeated use durability of the sleeve portion 5-2 can be improved.

[0032] The opening of the sleeve portion 5-2 of the cover member 5 can be suppressed without enlarging the cover member 5 or covering the entire outer surface of the cover member 5 with a protector, that is, without changing the overall height, width, or overall length of the motion guide device 10, so the motion guide device 10 of this embodiment is suitable for a miniature guide installed in a small space.

[0033] The joint 9a of the restraint member 9 contacts the side surface 5c of the sleeve portion 5-2 below the ball row 21b between the rolling groove 1a of the rail 1 and the rolling groove 4a of the carriage body 4, thereby effectively preventing the sleeve portion 5-2 of the cover member 5 from opening.

[0034] The joint 9a of the restraining member 9 contacts the inclined surface 5c1 at the lower end of the sleeve 5-2, which more effectively prevents the sleeve 5-2 from opening. In addition, the space between the inclined surface 5c1 and the rail 1 can be effectively utilized.

[0035] The bent portion 9b of the restraint member 9 is opened and elastically deformed when it enters the groove 11 of the cover member 5, so that the bent portion 9b can be elastically deformed so that the joint portion 9a presses against the side surface 5c of the sleeve portion 5-2.

[0036] Since the angle θ between the base groove 11a and the tip groove 11c of the cover member 5 is 90° or less, preferably an acute angle, the force with which the joint 9a of the restraining member 9 presses against the side surface 5c of the sleeve portion 5-2 can be increased, thereby making it possible to better prevent the restraining member 9 from falling off.

[0037] Since the width W1 of at least a portion of the base groove 11a of the cover member 5 is narrower than the width W2 of the tip groove 11c and the middle groove 11b, the bent portion 9b of the restraint member 9 can be prevented from shifting within the groove 11 of the cover member 5.

[0038] Since the restraining member 9 is wire-shaped and has a substantially rectangular cross section, the joint 9 a of the restraining member 9 can be brought into surface contact with the sleeve portion 5 - 2 of the cover member 5 .

[0039] This specification is based on Japanese Patent Application No. 2023-164687, filed September 27, 2023, the entire contents of which are incorporated herein by reference.

[0040] DESCRIPTION OF SYMBOLS 1...rail, 1a...rolling groove of rail, 2...carriage, 3...ball (rolling element), 4...carriage body, 4a...rolling groove of carriage body, 5...lid member, 5-2...sleeve portion of lid member, 5c...side surface of sleeve portion, 5c1...inclined surface of lower end portion of sleeve portion, 9...restraint member, 9a...joint portion, 9b...bent portion, 9b1...root portion of bent portion, 9b3...tip portion of bent portion, 10...motion guide device, 11...groove on end surface of lid member, 11a...root groove, 11c...tip groove, 21a, 21b...two upper and lower rows of balls (rolling element rows), θ...angle formed between root groove and tip groove, C2...turning path

Claims

1. A motion guide device comprising: a rail in which a rolling groove is formed; and a carriage guided on the rail via at least one rolling body, wherein the carriage comprises a carriage body in which a rolling groove is formed, and a pair of cover members provided at both ends of the carriage body and forming the outer periphery of a turning path, wherein the pair of cover members are sandwiched between a restraining member having a joint and a pair of bent portions, the bent portions of the restraining member enter into grooves formed on the end faces of the cover members, the joints of the restraining member contact the side surfaces of the sleeve portions of the cover members facing the side surfaces of the rail, and the bent portions are in a state of elastic deformation within the grooves so that the joints press against the side surfaces of the sleeve portions.

2. The motion guide device described in claim 1, characterized in that, when viewed from the front of the motion guide device, the joint of the restraint member contacts the side of the sleeve portion below the lower row of rolling elements of two upper and lower rows of rolling elements arranged between the rolling groove on the side of the rail and the rolling groove of the carriage body, or below a single row of rolling elements arranged between the rolling groove on the side of the rail and the rolling groove of the carriage body.

3. A motion guide device according to claim 2, characterized in that the joint contacts the inclined surface at the lower end of the sleeve portion.

4. A motion guide device as described in claim 1 or 2, characterized in that the groove of the cover member has a root groove into which the root portion of the bent portion fits and a tip groove into which the tip portion of the bent portion fits, and the restraint member fits into the groove of the cover member with the root portion and the tip portion open and elastically deformed.

5. A motion guide device according to claim 4, characterized in that the angle between said base groove and said tip groove is 90° or less.

6. The motion guide device according to claim 4, wherein the width of at least a portion of said base groove is narrower than the width of said tip groove.

7. A motion guide device as claimed in claim 1 or 2, characterized in that the restraining member is in the form of a wire having a substantially rectangular cross section.

Images