Linear motion guide device

Abstract

The present invention provides a linear motion guide device that reduces damage to the tip of the tongue section while smoothly guiding the guide into the circulation path, thereby improving operability. [Solution] In the linear motion guide device 10, an arc groove 222 forming the outer circumferential surface of the direction change path is formed on the slider body side surface of the end cap 22. A tongue portion 25 is formed at the track-side end of the arc groove 222 to scoop up the ball 3 from the track and guide it to the direction change path. The tip portion 251 of the tongue portion 25 comprises a plane 251a perpendicular to the direction along the track and a spherical surface 251b formed between the plane and the arc groove. The diameter of the spherical surface 251b is greater than or equal to the diameter Da of the ball 3, and the spherical surface 251b is formed away from the outer circumferential surface of the tongue portion 25.

Description

Technical Field

[0005] , , , ,

[0001] The present invention relates to a linear guide device having balls as rolling elements.

Background Art

[0002] For example, a linear guide device has a long guide rail, a slider disposed across the guide rail, and a plurality of balls as rolling elements. The guide rail and the slider each have a raceway groove that extends in the longitudinal direction of the guide rail and forms a ball track at positions facing each other.

[0003] [[ID=IC16]]The slider has a slider body and a pair of end caps. A ball raceway groove and a return path are formed in the slider body, and a ball direction-changing path is formed in the end cap. Balls are arranged in a circulation path composed of a track, a return path, and a direction-changing path, and the slider linearly moves along the guide rail via the balls that roll in the track under a load state.

[0004] A groove (hereinafter referred to as an "arc groove") having a semi-arc-shaped cross section that forms the outer peripheral surface of the direction-changing path is formed on the surface of the end cap on the side of the slider body. A tang portion is formed at the end of the arc groove on the track side to scoop up the balls from the track and guide them to the direction-changing path. When the linear guide device is driven at high speed, the balls repeatedly collide with the tang portion of the end cap at high speed, so the tang portion is likely to be damaged. Therefore, conventionally, methods for increasing the strength of the tang portion have been proposed.

[0005] For example, Patent Document 1 describes a tongue portion with a tip surface having a plane perpendicular to the direction along the track and an arc-shaped concave surface extending from the plane. The radius of curvature of the arc-shaped surface is smaller than the radius of the ball, and the center of the circle indicating the curvature of the arc-shaped surface lies on a line shifted from the bottom line of the arc groove by at least the amount of offset between the track groove on the guide rail side and the track groove on the slider side. As a result, when the ball is scooped up by the tongue portion, it comes into contact with the boundary between the plane and the arc-shaped surface at two points, and the impact force of the ball is dispersed, thereby suppressing the occurrence of cracks or fractures in the tongue portion. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-58003 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the linear motion guide device described in Patent Document 1 still has the problem that if the thickness of the tongue portion is thin, there is still a possibility of damage such as deformation and breakage, and if the thickness of the tongue portion is thick, the circulation of the rolling elements is hindered and the operability deteriorates.

[0008] The present invention has been made in view of the aforementioned problems, and its purpose is to provide a linear motion guide device that can improve operability by smoothly guiding the tip of the tongue portion into the circulation path while reducing damage to the tip portion of the tongue portion. [Means for solving the problem]

[0009] Therefore, the above objective of the present invention is achieved by the configuration of the linear motion guide device described below [1]. [1] It has a long guide rail, a slider positioned across the guide rail, and a plurality of balls, The guide rail and the slider each have track grooves that form the trajectory of the ball at positions opposite to each other, and both track grooves extend in the longitudinal direction of the guide rail. The slider has a slider body and a pair of end caps. The slider body has the track groove and the ball return path formed therein, and the end cap has the ball direction change path formed therein. The ball is placed within a circulating path consisting of the track, the return path, and the direction change path. A linear motion guide device in which the slider moves linearly along the guide rail via the ball that rolls within the track under load, An arc groove forming the outer circumferential surface of the direction change path is formed on the surface of the end cap facing the slider body. A tongue portion is formed at the end of the arc groove on the track side, which scoops up the ball from the track and guides it to the direction change path. The tip of the tongue portion comprises a plane perpendicular to the direction along the trajectory and a spherical surface formed between the plane and the arc groove, The diameter of the spherical surface is greater than or equal to the diameter of the ball. The spherical surface is formed separately from the outer circumferential surface of the tongue portion. Linear motion guide device. [Effects of the Invention]

[0010] According to the linear motion guide device of the present invention, the ball can be scooped up by contacting it with a spherical surface that has low surface pressure at contact, reducing damage to the tip of the tongue portion, and guiding it smoothly into the circulation path, thereby improving operability. [Brief explanation of the drawing]

[0011] [Figure 1] This is a partially broken perspective view showing a linear motion guide device according to one embodiment of the present invention. [Figure 2] This is a front view showing the slider body side of the end cap that constitutes the linear motion guide device in Figure 1. [Figure 3]It is a partial enlarged view of FIG. 2 showing the leg portion of the end cap. [Figure 4] It is an enlarged sectional view of a main part showing a tongue portion in an end cap together with a raceway groove of a guide rail. [Figure 5] (a) is a partial cutaway view of an end cap showing the periphery of an arc groove forming the outer peripheral surface of a direction-changing path, and (b) is an enlarged view of a main part near the tongue portion of (a). [Figure 6] (a) is a figure corresponding to FIG. 3 showing the leg portion of an end cap when the tongue portion does not have a recess, and (b) is an enlarged view of a main part near the tongue portion.

Embodiments for Carrying out the Invention

[0012] Hereinafter, a linear guide device according to an embodiment of the present invention will be described in detail based on the drawings. As shown in FIG. 1, the linear guide device 10 of the present embodiment includes a long guide rail 1, a slider 2 disposed across the guide rail 1, and a plurality of balls 3.

[0013] The slider 2 has a shape in which leg portions 2A disposed on both sides in the width direction of the guide rail 1 and a body portion 2B connecting the both leg portions 2A are integrated. The guide rail 1 is made of metal and has an upper surface 111 facing the inner surface of the body portion 2B of the slider 2 and a side surface 112 facing the inner surface of the leg portion 2A. A raceway groove 11 is formed at an upper corner portion formed by the upper surface 111 and the side surface 112 of the guide rail 1, and a raceway groove 12 is formed on the side surface 112 of the guide rail 1. A relief groove 13 for accommodating a holding wire (not shown) for holding a ball is formed at the groove bottom of the raceway groove 12.

[0014] The slider 2 is divided in the linear movement direction of the guide rail 1 into a slider main body 21, a pair of end caps 22, and a pair of side seals 23. The slider body 21 is made of metal, and on the inner side of the leg portion 21A, track grooves 211 and 212 are formed at positions facing the respective track grooves 11 and 12 of the guide rail 1. Return paths 216 corresponding to the respective track grooves 211 and 212 are formed in each leg portion 21A of the slider body 21.

[0015] As shown in FIG. 2, the end cap 22 is composed of a pair of leg portions 22A and a body portion 22B. On the surface of each leg portion 22A on the slider body side, arc grooves 221 and 222 forming the outer peripheral surface of the direction-changing path and a recess 223 for fitting the return guide 24 are formed. The left leg portion 22A in FIG. 2 shows the state before the return guide 24 is fitted, and the right leg portion 22A shows the state after the return guide 24 is fitted.

[0016] Inner arc surfaces 241 and 242 forming the inner peripheral surface of the direction-changing path are formed on the return guide 24. By fitting the return guide 24 into the recess ills 223 of the end cap 22, the arc grooves 221 and 222 of the end cap 22 and the inner arc surfaces 241 and 242 of the return guide 24 form the direction-changing path.

[0017] In the linear motion guide device 10, two pairs of four-row tracks are formed by the track grooves 11 and 12 of the guide rail 1 facing each other and the track grooves 211 and 212 of the slider 2, and each track and each return path 216 are connected by the direction-changing path. That is, it has two pairs of four-row circulation paths for the balls 3 composed of the tracks, the return paths 216, and the direction-changing path, and a plurality of balls 3 are arranged in each circulation path. Thereby, in the linear motion guide device 10, the slider 2 linearly moves along the guide rail 1 via the balls 3 that roll in a loaded state within the two pairs of four-row tracks.

[0018] Further, on the end cap 22, at the end of the arc groove 222 of the lower track on the track side, a tongue portion 25 is formed that scoops up the balls 3 from the track and guides them to the respective direction-changing paths. In this embodiment, a recess 26 for fitting the end portion of the holding wire is formed in the tongue portion 25 of the arc groove 222.

[0019] Next, the details of the shape of the tongue portion 25 will be explained with reference to Figures 3 to 5. Figure 3 is a magnified view of a portion of Figure 2, showing the legs of the end cap. Figure 4 is a magnified cross-sectional view of a key part of the end cap, showing the tongue portion together with the track groove of the guide rail. Figure 5(a) is a partial cutaway view of the end cap, showing the area around the arc groove that forms the outer surface of the direction change path, and Figure 5(b) is a magnified view of a key part near the tongue portion of Figure 5(a).

[0020] As shown in Figures 3 and 4, the tongue portion 25 is formed in a semi-cylindrical shape, protruding inward in the width direction from the widthwise inner surface of the leg portion 22A of the end cap 22 so as to enter the track groove 12 of the guide rail 1. The tip portion 251 of the tongue portion 25 consists of a plane 251a perpendicular to the direction L0 in which the track 41, consisting of track grooves 12,212, extends, and a spherical surface 251b formed between the plane 251a and the arc groove 222. The spherical surface 251b is formed away from the outer circumferential surface of the tongue portion 25. The ball 3 is scooped up from the track 41 by the tongue portion 25 and guided to the direction change path 42, which consists of the arc groove 222 of the end cap 22 and the inner arc surface 242 (see Figure 2) of the return guide 24.

[0021] The spherical surface 251b is formed at the boundary between the plane 251a and the arc groove 222, with the recess 26 in between, and is located on the inner diameter side of the outer circumferential surface of the tongue portion 25. The diameter of the spherical surface 251b is greater than or equal to the diameter Da of the ball 3. In particular, in this embodiment, the curvature of the spherical surface 251b is approximately the same as the curvature of the ball 3.

[0022] Furthermore, the minimum thickness of the flat surface 251a at the tip 251 of the tongue portion 25 is set to 1-3% of the diameter Da of the ball 3. In addition, the distance from the boundary between the flat surface 251a and the spherical surface 251b at the position of the minimum thickness of the flat surface 251a of the tongue portion 25 to the track groove 12 of the guide rail 1 is set to 5-7% of the diameter Da of the ball 3.

[0023] Furthermore, at the point of minimum thickness of the plane 251a of the tongue portion 25, the tangent line at the point where the spherical surface 251b and the plane 251a intersect has an angle of 30 to 60° with respect to the outer surface of the tongue portion 25. This defines the contact angle of the spherical surface 251b that the ball 3 contacts. In the case where there is a recess 26, the tangent line is the tangent line at the point where the edge line between the spherical surface 251b and the circumferential side surface 26a of the recess 26 intersects with the plane 251a.

[0024] In the above embodiment, a recess 26 is formed in the tongue portion 25. However, even in a tongue portion 25 that does not have a recess 26, a flat surface 251a and a spherical surface 251b can be formed to satisfy the above dimensional conditions, as shown in Figure 6.

[0025] Thus, in this embodiment, the tip portion 251 of the tongue portion 25, which has a flat surface 251a and a spherical surface 251b, has a flat surface 251a, and by providing the tip portion 251 of the tongue portion 25 with a flat surface 251a, the strength of the tip portion 251 can be increased and damage due to contact with the ball 3 can be reduced. In particular, by defining the minimum thickness of the flat surface 251a and the contact angle of the spherical surface 251b, the strength of the tip portion 251 can be reliably ensured and damage due to contact with the ball 3 can be reduced. Furthermore, the ball 3 can be made to contact with the spherical surface 251b, which reduces the surface pressure at the time of contact and reduces damage to the tip portion 251 of the tongue portion 25. Furthermore, by specifying the contact angle on the spherical surface 251b to 30° to 60°, guidance into the circulation path can be made smoother. Therefore, it is possible to suppress both the risk of damage and deterioration of operation. Furthermore, by setting the distance between the spherical surface 251b and the track groove 12 of the guide rail 1 at the position of the minimum thickness of the plane 251a to 5-7% of the diameter Da of the ball 3, the ball 3 can be more reliably brought into contact with the spherical surface 251b.

[0026] Furthermore, the present invention is not limited to the embodiments described above, and can be modified, improved, etc., as appropriate. In the above embodiment, the end cap is made of a metal material such as stainless steel, but the end cap of the present invention can also be made of materials other than metal, such as ceramics or resin.

[0027] As described above, the following matters are disclosed in this specification: (1) It has a long guide rail, a slider positioned across the guide rail, and a plurality of balls, The guide rail and the slider each have track grooves that form the trajectory of the ball at positions opposite to each other, and both track grooves extend in the longitudinal direction of the guide rail. The slider has a slider body and a pair of end caps. The slider body has the track groove and the ball return path formed therein, and the end cap has the ball direction change path formed therein. The ball is placed within a circulating path consisting of the track, the return path, and the direction change path. A linear motion guide device in which the slider moves linearly along the guide rail via the ball that rolls within the track under load, An arc groove forming the outer circumferential surface of the direction change path is formed on the surface of the end cap facing the slider body. A tongue portion is formed at the end of the arc groove on the track side, which scoops up the ball from the track and guides it to the direction change path. The tip of the tongue portion comprises a plane perpendicular to the direction along the trajectory and a spherical surface formed between the plane and the arc groove, The diameter of the spherical surface is greater than or equal to the diameter of the ball. The spherical surface is formed separately from the outer circumferential surface of the tongue portion. Linear motion guide device. This configuration allows the ball to be scooped up by contacting it with a spherical surface that has low contact pressure, reducing damage to the tip of the tongue and guiding it smoothly into the circulation path, thereby improving operability.

[0028] (2) The minimum thickness of the plane shall be 1 to 3% of the diameter Da of the ball. The angle between the tangent to the spherical surface at the position of the minimum thickness of the plane and the outer surface of the tongue portion is 30° to 60°. (1) The linear motion guide device described above. This configuration ensures the strength of the tip of the tongue, reduces damage to the tip of the tongue, and smoothly guides the circulating material into the circulation path, thereby improving operability.

[0029] (3) The distance between the spherical surface and the track groove of the guide rail at the position of the minimum thickness of the plane shall be 5 to 7% of the diameter Da of the ball. (2) The linear motion guide device described above. This configuration allows for more reliable contact of the ball with the spherical surface. [Explanation of Symbols]

[0030] 1 Guide rail 2 Sliders 2A Slider legs 2B Slider's torso 3 balls 10 Linear motion guide device 11 Guide rail track groove 12 Guide rail track groove 13 Escape ditch 21 Slider body 22 End caps 22A End cap legs 22B End cap body 23 Side seal 24 Return Guide 25 Tongue section 26 recesses 41 orbit 42 Turnaround 111 Top surface of guide rail 211 Slider track groove 212 Slider track groove 216 Return path 221 Circular groove forming the outer surface of the turning ramp 222 Circular groove forming the outer surface of the turning ramp 241,242 Inner circular arc surface forming the inner circumferential surface of the turning path 251 Tip of the tongue 251a Flat surface of the tip 251b Spherical surface at the tip

Claims

1. It comprises a long guide rail, a slider positioned across the guide rail, and a plurality of balls, The guide rail and the slider each have track grooves that form the trajectory of the ball at positions opposite to each other, and both track grooves extend in the longitudinal direction of the guide rail. The slider has a slider body and a pair of end caps. The slider body has the track groove and the ball return path formed therein, and the end cap has the ball direction change path formed therein. The ball is placed within a circulation path consisting of the track groove, the return path, and the direction change path. A linear motion guide device in which the slider moves linearly along the guide rail via the ball that rolls within the track under load, An arc groove forming the outer circumferential surface of the direction change path is formed on the surface of the end cap facing the slider body. A tongue portion is formed at the end of the arc groove on the track side, which scoops up the ball from the track and guides it to the direction change path. The tip of the tongue portion comprises a plane perpendicular to the direction along the trajectory and a spherical surface formed between the plane and the arc groove, The diameter of the spherical surface is greater than or equal to the diameter of the ball. The spherical surface is formed separately from the outer circumferential surface of the tongue portion. Linear motion guide device.

2. The minimum thickness of the plane is 1 to 3% of the diameter Da of the ball. The angle between the tangent to the spherical surface at the position of the minimum thickness of the plane and the outer surface of the tongue portion is 30° to 60°. The linear motion guide device according to claim 1.

3. The distance between the spherical surface and the track groove of the guide rail at the position of the minimum thickness of the plane is 5 to 7% of the diameter Da of the ball. The linear motion guide device according to claim 2.

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