Linear guide

Abstract

To provide a linear guide capable of reliably preventing the breakage of a scooping-up part to guide a spherical rolling element to a turnaround path of an end cap.SOLUTION: An end cap 30 arranged at the end of a slider body is constructed so that, in a projection drawing projecting the shapes of a turnaround path 26 and a scooping-up part 45 and the shape of a guide rail 3 on a projection plane perpendicular to the moving direction of a slider, the end of the scooping-up part 45 does not cross a straight line L connecting an inlet center O1 of the turnaround path 26 connected to a load rolling path and an outlet center O2 of the turnaround path 26 connected to a rolling element return path.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a linear guide, and more particularly to a linear guide that can prevent damage to a scooping portion that guides a ball into a direction-changing path of an end cap. [Background technology]

[0002] Conventionally, a linear guide (linear guide) includes a guide rail extending in the axial direction and a slider mounted on the guide rail so as to be movable relative to the guide rail, and the slider moves relative to the guide rail in the axial direction via a plurality of spherical rolling elements (balls) that circulate between the guide rail and a rolling element circulating path (rolling element rolling path) formed in the slider. Such linear guides are widely used in the linear motion mechanisms of various production facilities.

[0003] The slider body of the slider has a slider-side raceway groove that forms a loaded rolling path together with the rail-side raceway groove of the guide rail, and a rolling element return path formed approximately parallel to the slider-side raceway groove. A pair of end caps are attached to the axial ends of the slider body to form the slider. The end caps have direction change paths that connect the loaded rolling path and the rolling element return path, and have scooping portions that guide the spherical rolling elements rolling in the loaded rolling path into the direction change paths.

[0004] This scooping section is necessarily wedge-shaped (tapered) in cross section, gradually sloping from the loaded rolling path side to the direction change path side, which poses the problem of the scooping section being damaged by collisions with the spherical rolling elements rolling along the loaded rolling path.

[0005] Therefore, the motion guide device (linear guide) disclosed in Patent Document 1 is configured to bring balls (spherical rolling elements) rolling along a loaded ball passage (loaded rolling path) provided between a track member (guide rail) and a movable member body (slider body) into contact with a first contact surface that intersects with the loaded ball passage and continues to a direction change path in a cover member (end cap).The ball's traveling direction is then changed and it is guided to a second contact surface provided on the opposite side of the first contact surface and the ball rolling surface, thereby guiding the ball into the direction change path. The motion guide device of Patent Document 1 prevents damage to the cover member by eliminating the tapered scooping section that guides balls transferred through the loaded ball passage into the direction change passage as in the past.

[0006] Furthermore, in the motion guide device disclosed in Patent Document 2, the introduction section (scooping section) includes a thick section and a thin section on either side of the ball, and in a cross section perpendicular to the direction in which the ball travels, the area surrounded by the thick section is larger than the area surrounded by the thin section. The angle between a first contact angle line connecting the contact point between the ball and the thick section and the center of the ball and the turning direction in which the ball is guided from the ball rolling section (loaded rolling path) to the direction change path is smaller than the angle between a second contact angle line connecting the contact point between the ball and the thin section and the center of the ball and the turning direction. In the motion guide device of Patent Document 2, the force acting from the ball to the introduction portion acts mainly on the thick-walled portion, which has great mechanical strength, and is less likely to act on the thin-walled portion, thereby preventing damage to the thin-walled portion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2013 / 065663 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-139008 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in a configuration in which a first contact surface and a second contact surface are provided within a direction change path, as in the motion guide device of Patent Document 1, strict dimensional accuracy and assembly accuracy are required for the parts (moving member body and cover member) that make up the infinite circulation path (rolling body circulation path), which poses problems in manufacturability. Furthermore, in a configuration in which the introduction section has two-point contact, as in the motion guide device of Patent Document 2, due to the dimensional accuracy of the ball and the introduction section, when the ball actually begins to come into contact with the introduction section, it is thought that there is only one-point contact, and this is thought to have little effect in preventing damage to the introduction section, which is the intended effect.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a linear guide that can reliably prevent damage to the scooping portion that guides the spherical rolling elements into the direction change path of the end cap. [Means for solving the problem]

[0010] The above object of the present invention can be achieved by the following configuration. a guide rail having a rail-side raceway groove formed on a side surface along the longitudinal direction; a slider body of a slider having a slider-side raceway groove that forms a loaded rolling path together with the rail-side raceway groove, and a rolling element return path formed substantially parallel to the slider-side raceway groove, the slider body slidably engaging across the guide rail; a pair of end caps each having a direction change path connecting the load rolling path and the rolling element return path and attached to an axial end of the slider body; a spherical rolling element that rolls in the load rolling path, the rolling element return path, and the direction changing path; a scooping portion formed on the end cap to guide the spherical rolling element rolling in the loaded rolling path to the direction changing path, In a projection view in which the shapes of the direction change path and the scooping portion and the shape of the guide rail are projected onto a projection plane perpendicular to the traveling direction of the slider, The end of the scooping portion is configured not to intersect with a straight line connecting an entrance center of the direction change path connected to the load rolling path and an exit center of the direction change path connected to the rolling element return path. A linear guide characterized by: [Effects of the Invention]

[0011] According to the linear guide of the present invention, it is possible to provide a linear guide that can reliably prevent damage to the scooping portion that guides the spherical rolling elements into the direction change path of the end cap. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a linear guide according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic top view of the linear guide shown in FIG. 1, with a portion of the top surface thereof cut away. [Figure 3] FIG. 3 is a front view of the end cap shown in FIG. 1 as viewed from the opposing slider body side. [Figure 4] FIG. 4 is a projection view of the shape of the direction change path and the scooping portion of the end cap and the shape of the guide rail in part A of FIG. 3, projected perpendicular to the traveling direction of the slider. [Figure 5] FIG. 5 is a projection view of the shape of the direction change path and the scooping portion of the end cap and the shape of the guide rail in part A of FIG. 3, projected onto a projection plane perpendicular to the traveling direction of the slider. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, linear guides according to each embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the vertical direction and width direction of the slider respectively refer to the directions in a state in which the slider is assembled to a guide rail arranged with the longitudinal direction horizontal, and the width direction of the slider is the direction perpendicular to the longitudinal direction of the guide rail and the vertical direction of the slider, and is also referred to as the left-right direction (see FIG. 1). The longitudinal direction is also referred to as the axial direction.

[0014] As shown in FIG. 1, a linear guide 1 according to one embodiment of the present invention comprises a linear guide rail 3 and a slider 20 having a C-shaped cross section, which is assembled so as to straddle the guide rail 3 and slidably engages with the guide rail 3 via a plurality of spherical rolling elements (balls) not shown.

[0015] The guide rail 3 is made of metal, and on both widthwise sides thereof, two rows on each side are formed with rail-side track grooves 5 extending in the longitudinal direction, for a total of four rows. The guide rail 3 has a plurality of rail mounting holes 4 penetrating the guide rail 3 in the height direction, and rail fixing bolts (not shown) are inserted into these rail mounting holes 4 to fix the guide rail 3 to a mounting surface (not shown).

[0016] As shown in Figures 1 to 3, the slider 20 of this embodiment comprises a slider body 21 having sleeve portions on both the left and right sides of the guide rail 3, a pair of end caps 30, 30 attached to both ends of the slider body 21 in the front-to-rear direction (axial direction), return guides 40, 40 incorporated into each of these end caps 30, 30, and a pair of side seals 60, 60 that seal the gap between the guide rail 3 and the end caps 30, 30.

[0017] The slider body 21 has multiple stages (two stages in this embodiment) of slider-side raceway grooves 23 and rolling element return paths 28 on both the left and right sides. The slider-side raceway grooves 23 are formed on the inner surfaces of both sleeve portions of the slider body 21 and face the rail-side raceway grooves 5 of the guide rail 3, respectively, and the rail-side raceway grooves 5 and the slider-side raceway grooves 23 form two stages of loaded rolling paths 24. The rolling element return paths 28 are formed by two holes that penetrate the thick portions of both sleeve portions in the longitudinal direction (axial direction) of the guide rail 3. In addition, the top surface of the slider body 21 is provided with driven body fixing screw insertion holes 25 through which bolts for fixing a driven body such as a table to the slider 20 are inserted.

[0018] 3, the end cap 30 of this embodiment is, for example, an injection-molded product made of synthetic resin, and is formed with a C-shaped cross section similar to the slider body 21. The end cap 30 is provided with a plurality of mounting screw insertion holes 34, and the end cap 30, together with the side seal 60, is fastened to the front-rear end 21 a of the slider body 21 by mounting screws 35 inserted into the mounting screw insertion holes 34.

[0019] In addition, on the left and right sleeve portions 31 of the end cap 30, semi-disk-shaped recesses 36 are formed in two tiers, upper and lower, on the abutment surface 31a side facing the front-to-rear end portion 21a of the slider body 21, and a semi-cylindrical recess 39 is formed at a position crossing the widthwise center of the two tiers of semi-disk-shaped recesses 36.

[0020] The return guide 40 is formed into a semi-cylindrical shape by injection molding of resin or metal, or by using a 3D printer. Possible resin materials include engineering plastics such as polyacetal, polyamide, and PEEK materials, which may be reinforced with approximately 2 to 50% glass fiber or carbon fiber. Possible metal materials include austenitic stainless steels such as SUS304 and SUS316. It is also possible to form the return guide 40 by cutting resin or metal materials.

[0021] The semi-cylindrical return guide 40 is attached to the abutment surface 31a of the end cap 30 by fitting into the semi-cylindrical recess 39 of the end cap 30 with its cylindrical surface facing inward. As a result, the cylindrical surface of the return guide 40 and the semi-disk-shaped recess 36 of the end cap 30 define curved, annular direction change paths 26 in two stages, upper and lower, on the abutment surface 31a of the end cap 30. The direction change paths 26 are connected to the two stages of the load rolling paths 24 and the rolling element return paths 28 of the slider body 21, respectively.

[0022] The load rolling path 24, the rolling element return path 28, and the direction change path 26 form a rolling element circulation path 27. A large number of spherical rolling elements (balls) 10 are loaded in the rolling element circulation path 27 so that they can roll freely, and the slider 20 can move relatively along the axial direction on the guide rail 3 via these spherical rolling elements 10 that circulate endlessly while rolling within the rolling element circulation path 27.

[0023] As shown in FIG. 3, the opposing surface 40a of the return guide 40 facing the front-rear end 21a of the slider body 21 is recessed with semicircular lubricant passage grooves 42 in cross section, each of which communicates with the direction change path 26 via a plurality of (three in this embodiment) lubricant supply holes 44 arranged in series along the lubricant supply direction (vertical direction).

[0024] A lubricant passage groove 37 extending in the width direction is recessed in the horizontal portion 32 of the end cap 30 on the side of the abutment surface 32a facing the front-rear end of the slider body 21. A lubricant introduction portion 33 for introducing lubricant from the nipple 50 into the end cap 30 is drilled in the center of the lubricant passage groove 37. Further, a lubricant passage groove 38 is recessed in the contact surfaces 31 a of the left and right sleeve portions 31 of the end cap 30 , extending from the lubricant passage groove 37 to the lubricant passage groove 42 of the return guide 40 .

[0025] Then, by fixing the end cap 30 to the front-rear end of the slider body 21, a lubricant passage that communicates with the lubricant inlet portion 33 and guides the lubricant to the direction changing path 26 is defined between the lubricant passage grooves 37, 38, and 42 in the end cap 30 and the end face of the slider body 21. The lubricant introduced into the end cap 30 from the nipple 50 passes from the lubricant inlet portion 33 through the lubricant passage grooves 37 and 38 to the lubricant passage groove 42, and is then supplied to the direction changing path 26 via the lubricant supply hole 44.

[0026] As shown in FIG. 3, the direction change path 26 according to this embodiment has a scooping portion 45 formed in the end cap 30 to guide the spherical rolling element 10 rolling in the loaded rolling path 24 into the direction change path 26. As shown in FIG. 4, in a projection diagram in which the shapes of the direction change path 26 and the scooping portion 45 and the shape of the guide rail 3 are projected onto a projection plane perpendicular to the traveling direction of the slider 20, the end portion of the scooping portion 45 (area S in FIG. 4) does not intersect with a straight line L connecting an entrance center O1 of the direction change path 26 connecting with the load rolling path 24 and an exit center O2 of the direction change path 26 connecting with the rolling element return path 28.

[0027] As a result, in the linear guide 1 according to this embodiment, the spherical rolling body 10, which has moved from the loaded rolling path 24 to the direction change path 26 and is now in an unloaded state, collides with the scooping portion 45 in a stable state with little vibration while being embraced by the wall surface of the direction change path 26 and the rail-side raceway groove 5. Therefore, compared to the conventional case where the spherical rolling body 10 collides with the scooping portion in an unstable state due to a small area that can hold the spherical rolling body 10, the end cap 30 of this embodiment reduces the impact of the spherical rolling body 10 on the scooping portion 45, and has the effect of preventing damage to the scooping portion 45.

[0028] Therefore, the linear guide 1 according to this embodiment can reliably prevent damage to the scooping portion 45 for guiding the spherical rolling elements 10 into the direction change path 26 of the end cap 30.

[0029] Furthermore, as shown in FIG. 5, in a projection view in which the shapes of the direction change path 26 and the scooping portion 45, and the shape of the guide rail 3 are projected onto a projection plane perpendicular to the traveling direction of the slider 20, the guide rail 3 and the end cap 30 of the linear guide 1 according to this embodiment are configured such that when a virtual tangent M is drawn to a virtual circle C formed by extending the wall surface 5a of the rail-side raceway groove 5, which is formed by a single arc, and the virtual tangent M is parallel to a straight line L connecting the entrance center O1 of the direction change path 26 connecting with the load rolling path 24 and the exit center O2 of the direction change path 26 connecting with the rolling element return path 28, the contact point P is outside the contour line of the guide rail 3.

[0030] As a result, according to the linear guide 1 of this embodiment, the spherical rolling elements 10 passing through the direction change paths 26 and moving to the loaded rolling paths 24 can avoid interference with the corner portions 5b of the rail-side raceway grooves 5. Therefore, the guide rail 3 and the end cap 30 of this embodiment also have the effect of preventing damage to the spherical rolling elements 10.

[0031] The present invention is not limited to the above-described embodiments, and can be appropriately modified, improved, etc. Furthermore, the material, shape, size, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as they can achieve the present invention.

[0032] Here, the features of the above-described embodiments of the linear guide according to the present invention will be briefly summarized and listed below in [1] to [2]. [1] A guide rail (3) having a rail-side track groove (5) formed on the side surface along the longitudinal direction; a slider body (21) of a slider (20) having a slider-side raceway groove (23) that forms a loaded rolling path (24) together with the rail-side raceway groove (5) and a rolling element return path (28) formed substantially parallel to the slider-side raceway groove (23), and slidably engaging with the guide rail (3) so as to straddle the guide rail (3); a pair of end caps (30) each having a direction change path (26) connecting the load rolling path (24) and the rolling element return path (28) and attached to an axial end of the slider body (21); a spherical rolling element (10) that rolls in the load rolling path (24), the rolling element return path (28), and the direction changing path (26); a scooping portion (45) formed in the end cap (30) for guiding the spherical rolling element (10) rolling in the load rolling path (24) to the direction changing path (26), In this projection view, the shapes of the direction change path (26) and the scooping portion (45) and the shape of the guide rail (3) are projected onto a projection plane perpendicular to the moving direction (axial direction) of the slider (20), an end (region S) of the scooping portion (45) is configured not to intersect with a straight line (L) connecting an entrance center (O1) of the direction change path (26) connected to the load rolling path (24) and an exit center (O2) of the direction change path (26) connected to the rolling element return path (28); A linear guide (1) characterized by:

[0033] According to the configuration [1] above, the spherical rolling element (10) that has moved from the loaded rolling path (24) to the direction change path (26) and is now in an unloaded state collides with the scooping portion (45) in a stable state with little vibration while being held by the wall surface of the direction change path (26) and the rail-side track groove (5). Therefore, compared to the conventional case where the spherical rolling body (10) collides with the scooping portion in an unstable state due to a small area for holding the spherical rolling body (10), the end cap (30) of this configuration reduces the impact of the spherical rolling body (10) on the scooping portion (45), and has the effect of preventing damage to the scooping portion (45).

[0034] [2] In a projection diagram in which the shapes of the direction change path (26) and the scooping portion (45) and the shape of the guide rail (3) are projected onto a projection plane perpendicular to the moving direction (axial direction) of the slider (20), When a virtual tangent (M) is drawn to a virtual circle (C) formed by extending a wall surface (5a) of the rail-side raceway groove (5) formed by a single arc, the virtual tangent (M) is parallel to a straight line (L) connecting an entrance center (O1) of the direction change path (26) connecting with the loaded rolling path (24) and an exit center (O2) of the direction change path (26) connecting with the rolling element return path (28), and the tangent point (P) is outside the contour line of the guide rail (3). The linear guide (1) according to the above [1].

[0035] According to the configuration [2] above, the spherical rolling elements 10 passing through the direction change paths 26 and moving to the loaded rolling paths 24 can avoid interference with the corners 5b of the rail-side raceway grooves 5. Therefore, the guide rail 3 and end caps 30 of this configuration also have the effect of preventing damage to the spherical rolling elements 10. [Explanation of symbols]

[0036] 1 Linear guide 3 Guide rails 5 Rail side track groove 10 spherical rolling elements 20 Slider 21 Slider body 23 Slider side raceway groove 24 Load rolling path 26 Turning Point 28 Rolling element return path 30 End Cap 33 Lubricant introduction section 45 Scooping section O1 Turning point entrance center O2 Turning point exit center

Claims

[Claim 1] a guide rail having a rail-side raceway groove formed on a side surface along the longitudinal direction; a slider body of a slider having a slider-side raceway groove that forms a loaded rolling path together with the rail-side raceway groove, and a rolling element return path formed substantially parallel to the slider-side raceway groove, the slider body slidably engaging across the guide rail; a pair of end caps each having a direction change path connecting the load rolling path and the rolling element return path and attached to an axial end of the slider body; a spherical rolling element that rolls in the load rolling path, the rolling element return path, and the direction changing path; a scooping portion formed on the end cap to guide the spherical rolling element rolling in the loaded rolling path to the direction changing path, In a projection view in which the shapes of the direction change path and the scooping portion and the shape of the guide rail are projected onto a projection plane perpendicular to the traveling direction of the slider, an end of the scooping portion does not intersect with a straight line connecting an entrance center of the direction change path connected to the load rolling path and an exit center of the direction change path connected to the rolling element return path, and when a virtual tangent is drawn to a virtual circle formed by extending a wall surface of the rail-side raceway groove formed by a single arc, the virtual tangent is parallel to a straight line connecting an entrance center of the direction change path connected to the loaded rolling path and an exit center of the direction change path connected to the rolling element return path, and the point of contact is located outside the contour line of the guide rail.

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