Linear motion guide device and manufacturing method therefor

Abstract

In this linear motion guide device, when a plane passing through the width-direction center of a slider body and the longitudinal axis of a guide rail is defined as a vertical center plane CP, a plane orthogonal to the vertical center plane CP and passing through the linear part center line of a rolling path is defined as a horizontal reference plane HP, and a plane parallel to the vertical center plane CP and crossing a second inclined surface and a third inclined surface is defined as a vertical reference plane VP, a point P2 on a first inclined surface farthest from the vertical reference plane VP is separated from the vertical reference plane VP farther than a point P1 on a first raceway surface farthest from the vertical reference plane VP, and a point P4 on the second inclined surface and the third inclined surface farthest from the horizontal reference plane HP is separated from the horizontal reference plane HP farther than a point P3 on the first raceway surface farthest from the horizontal reference plane HP.

Description

Linear guide device and manufacturing method thereof

[0001] The present invention relates to a linear guide device and a manufacturing method thereof.

[0002] Linear guide devices, which guide objects linearly while allowing rolling elements such as rollers and balls to circulate endlessly inside, are one of the important machine elements that have a significant impact on the motion accuracy of semiconductor manufacturing equipment, ultra-precision processing machines, ultra-precision measuring instruments, etc.

[0003] The linear guide device comprises a guide rail and a slider body. The guide rail is provided with rail-side rolling element raceway grooves. The slider body is provided with slider-side rolling element raceway grooves facing the rail-side rolling element raceway grooves, and is supported by the guide rail so as to be movable in the axial direction via the rolling of multiple rolling elements disposed in rolling paths formed between the slider-side rolling element raceway grooves and the rail-side rolling element raceway grooves. The linear guide device further comprises a rolling element return path provided in the slider body so as to be approximately parallel to the rolling path, and direction change paths provided in end caps attached to both ends of the slider body in the moving direction, which connect the rolling path and the rolling element return path.

[0004] When the rolling elements of a linear motion guiding device circulate endlessly through the rolling passage, direction change passage, and rolling element return passage, periodic micro-vibrations (hereinafter referred to as rolling element passing vibrations) occur, which greatly affect the motion accuracy of the aforementioned equipment. Rolling element passing vibrations occur when a rolling element, which is rolling in the rolling passage (loaded area) while being loaded by preload or external load, releases the load as it leaves the loaded area and enters the rolling element circulation path (unloaded area), or conversely, when it takes on a new load as it enters the loaded area from the unloaded area.

[0005] To suppress this rolling element passing vibration, inclined surfaces called crownings are provided at both ends of the slider-side rolling element raceway grooves that form the rolling passage. The crownings allow the load fluctuations that accompany the rolling elements entering and leaving the load zone to occur gradually, thereby reducing the rolling element passing vibration.

[0006] Patent Document 1 discloses a linear guide bearing comprising: a first crowning having a curved surface shape, inclined portions provided at both ends of the slider-side rolling element raceway groove, formed with a large radius of curvature so that the slope continues from the slider-side rolling element raceway groove and becomes gentler; a second crowning adjacent to the first crowning, extending toward the inner peripheral surface of the direction change path, with a steeper slope than the first crowning and shorter in axial length than the first crowning; and an inclined surface provided between the second crowning and the end face of the slider body, which is more inclined than the first crowning and second crowning.

[0007] Japanese Patent Application Publication No. 2008-133837

[0008] However, when a ball enters the return passage, the center of the ball may be misaligned with the center line of the return passage, which can cause a problem of so-called ball eccentricity. According to the technology of Patent Document 1, by combining a first crowning and a second crowning, a sufficient drop can be formed in the groove bottom direction where the crowning is formed to relieve the eccentricity of the ball. However, since the slider groove end cannot provide relief for the eccentricity of the ball in directions other than the groove bottom direction, especially in directions perpendicular to the groove bottom, there is a risk that the ball will collide hard with the end face of the slider, which could deteriorate durability.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a linear guide device and a manufacturing method thereof that can ensure smooth ball movement while mitigating impact forces regardless of the behavior of the ball entering the track surface.

[0010] a slider body having raceway grooves disposed opposite to the raceway grooves of the guide rail to form the rolling paths of the rolling elements, and a return path for the rolling elements; and an end cap having a direction change path connecting the return path and the rolling path; the raceway groove of the slider body having a first raceway surface on the central side of the rolling path and a second raceway surface on the end side of the rolling path; and the second raceway surface having a first inclined surface extending from the first raceway surface to the end face of the slider body, and a second inclined surface and a third inclined surface extending to the end face of the slider body or to the vicinity thereof without being continuous with the first raceway surface, When a plane passing through the widthwise center of the slider body and the longitudinal axis of the guide rail is defined as a vertical center plane CP, a plane perpendicular to the vertical center plane CP and passing through the center line of the straight portion of the rolling path is defined as a horizontal reference plane HP, and a plane parallel to the vertical center plane CP and intersecting the second inclined surface and the third inclined surface is defined as a vertical reference plane VP, point P2 on the first inclined surface farthest from the vertical reference plane VP is farther from the vertical reference plane VP than point P1 on the first raceway surface farthest from the vertical reference plane VP, and point P4 on the second inclined surface and the third inclined surface farthest from the horizontal reference plane HP is farther from the horizontal reference plane HP than point P3 on the first raceway surface farthest from the horizontal reference plane HP.

[0011] The manufacturing method of the linear guide device of the present invention is a manufacturing method of a linear guide device comprising: a guide rail; a slider arranged so as to move relatively to the guide rail in a longitudinal direction; and a plurality of rolling elements arranged so as to be able to roll along a rolling path formed between the guide rail and the slider, wherein the slider comprises: a slider body having raceway grooves arranged opposite to the raceway grooves of the guide rail to form the rolling paths of the rolling elements, and a return path for the rolling elements; and an end cap having a direction change path connecting the return path and the rolling path, wherein the raceway groove of the slider body has a first raceway surface on the central side of the rolling path and a second raceway surface on the end side of the rolling path, and the second raceway surface has a first inclined surface extending from the first raceway surface to an end face of the slider body, and a second inclined surface and a third inclined surface extending to the end face of the slider body or to the vicinity thereof without being continuous with the first raceway surface, the slider body has a trunk portion and a pair of legs arranged at both ends in a width direction of the trunk portion, and when the width direction of the slider body is defined as an X direction, the longitudinal direction of the slider body is defined as a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction, the method comprises the steps of: forming the first orbital surface by bringing a tool having a ring-shaped grinding stone and rotating around a rotation axis RO into contact with longitudinal centers of opposing side surfaces of the legs of the slider body and moving the tool in the Y direction toward the longitudinal end of the slider body; forming the first inclined surface of the second orbital surface by moving the tool in the Y direction and the X direction so as to approach the width end of the slider body as it approaches the longitudinal end of the slider body; and forming the second inclined surface and part of the third inclined surface by moving the tool in the Z direction after reaching the longitudinal end of the slider body.

[0012] According to the present invention, it is possible to provide a linear guide device and a manufacturing method thereof that can ensure smooth ball movement while mitigating impact forces regardless of the behavior of the ball entering the raceway surface.

[0013] FIG. 1 is a perspective view showing a linear guide device according to a first embodiment of the present invention. FIG. 2 is a front view of the slider body of the linear guide device of FIG. 1, as seen from the longitudinal direction of the guide rail. FIG. 3 is a cross-sectional view taken along III-III in FIG. 2. FIG. 4 is a perspective view of the slider body. FIG. 5 is an enlarged perspective view of portion V in FIG. 4. FIG. 6 is a cross-sectional view taken along VI-VI in FIG. 4. FIG. 7 is a cross-sectional view taken along VII-VII in FIG. 4. FIG. 8 is an enlarged view of portion VIII in FIG. 7. FIG. 9 is an enlarged view of portion IX in FIG. 6. FIG. 10 is a schematic view showing a cross section similar to FIG. 8 according to a comparative example, together with rolling elements. FIG. 11 is a schematic view showing a cross section similar to FIG. 8 according to the first embodiment, together with rolling elements. FIG. 12 is a schematic view showing an enlarged view of portion XII in FIG. 6 according to the first embodiment, together with rolling elements. Fig. 13 is a schematic diagram showing a portion of an end surface of a blank (material) of the slider body as viewed from the longitudinal direction, and a grinding tool. Fig. 14 is a schematic diagram showing the cross section of Fig. 6 and a processing tool. Fig. 15 is a schematic diagram showing a trajectory of a portion of the processing tool. Fig. 16 is a cross-sectional view similar to Fig. 8 showing Modification 1 of the first embodiment. Fig. 17 is a cross-sectional view similar to Fig. 9 showing Modification 1 of the first embodiment. Fig. 18 is a cross-sectional view similar to Fig. 9 showing Modification 2 of the first embodiment. Fig. 19 is a cross-sectional view similar to Fig. 2 of a slider body according to a second embodiment.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, terms indicating directions (upward, downward, etc.) refer to the respective directions in Figure 2 unless otherwise specified. Furthermore, the term "longitudinal direction" refers to the longitudinal direction of the guide rail or slider.

[0015] First Embodiment FIG. 1 is a perspective view showing a linear guide device according to a first embodiment of the present invention. FIG. 2 is a front view of the slider body of the linear guide device of FIG. 1 as seen from the longitudinal direction of the guide rail, with the end caps omitted. FIG. 3 is a cross-sectional view taken along III-III in FIG. 2, with the cage 4 and cage groove 10Ba omitted. In FIG. 2, a plane passing through the widthwise center of the slider body 2A and the longitudinal axis of the guide rail 1 is defined as a vertical center plane CP, and a plane perpendicular to the vertical center plane CP and passing through the center lines O1 of the linear portions of a pair of rolling paths 13A arranged on both sides of the guide rail 1 is defined as a horizontal reference plane HP. Furthermore, a plane shifted from the center lines O1 of the linear portions of the rolling paths 13A toward the first raceway surface and perpendicular to the horizontal reference plane HP is defined as a vertical reference plane VP. The vertical reference plane VP is a plane parallel to the vertical center plane CP and intersects with the second and third inclined planes described below. Although details will be described later, the configuration of each part will be described using the vertical reference plane VP and horizontal reference plane HP corresponding to one of the rolling paths 13A.

[0016] A slider 2 having a substantially U-shaped cross section is mounted along a linearly extending guide rail 1 having a substantially rectangular cross section so as to be movable in the longitudinal direction of the guide rail 1. At the ridge where both left and right side surfaces 1a, 1a in the width direction of the guide rail 1 intersect with the top surface 1b, track grooves 10A, 10A consisting of recessed grooves having a cross section shaped like a quarter of a circle are formed along the longitudinal direction.

[0017] Furthermore, raceway grooves 10B, 10B each consisting of a recessed groove having a substantially semicircular cross section are formed along the longitudinal direction at approximately the center in the vertical direction of both left and right widthwise side surfaces 1a, 1a of the guide rail 1. Furthermore, at the groove bottoms of the raceway grooves 10B, 10B, a cage groove 10Ba (wire groove) that accommodates a part of the cage 4 and guides the cage 4 during movement of the slider 2 is formed along the longitudinal direction between both ends of the movement area of ​​the slider 2 (for example, between both ends in the longitudinal direction of the guide rail 1). The cross section of the cage groove 10Ba is, for example, substantially rectangular.

[0018] The slider 2 is made up of a flat body 7 facing the upper surface 1b of the guide rail 1 and two legs 6, 6 extending downward from both the left and right sides of the body 7 and facing the side surface 1a, and the angle between the body 7 and the legs 6, 6 is approximately right angles, so that the cross section of the slider 2 is approximately U-shaped. Furthermore, the slider 2 is attached movably relative to the guide rail 1, with the guide rail 1 sandwiched between the legs 6, 6.

[0019] The slider 2 comprises a slider body 2A and end caps 2B, 2B detachably attached to both ends (longitudinal ends) of the slider body 2A. Furthermore, side seals 5, 5 are attached to both ends of the slider 2 (longitudinal outer end surfaces of each end cap 2B) and slide against the outer surfaces (upper surface 1b and side surfaces 1a, 1a) of the guide rail 1 to seal the portions of the opening of the gap between the guide rail 1 and the slider 2 that face the longitudinal end surfaces, and under seals 8, 8 are attached to the bottom of the slider 2 to seal the portions of the opening of the gap between the guide rail 1 and the slider 2 that face the underside of the slider 2. These side seals 5, 5 and under seals 8, 8 prevent foreign matter from entering the gap from the outside and lubricant from leaking from the gap to the outside.

[0020] Furthermore, raceway grooves 11A, 11A, 11B, 11B (hereinafter, these may be collectively referred to as 11) consisting of recessed grooves with a substantially semicircular cross section that face raceway grooves 10A, 10A, 10B, 10B (hereinafter, these may be collectively referred to as 10) of the guide rail 1 are formed at the corners and approximately the center in the vertical direction of the inner surfaces of both the left and right legs 6, 6 of the slider body 2A. Furthermore, rolling paths 13A, 13A, 13B, 13B (hereinafter, these may be collectively referred to as 13) with a substantially circular cross section are formed between the raceway groove 10 of the guide rail 1 and the raceway groove 11 of the slider 2, and these rolling paths extend in the longitudinal direction.

[0021] A plurality of rolling elements 3 (balls) are loaded in the rolling passage 13 so as to be able to roll freely while being held by a cage 4, and the slider 2 is guided by the guide rail 1 and is able to move in the longitudinal direction via the rolling of the rolling elements 3 in the rolling passage 13. The cage 4 is formed of, for example, a wire, and holds the rolling elements 3 to prevent them from falling off the slider 2 before it is assembled to the guide rail 1.

[0022] The number of raceway grooves 10, 11 provided on the guide rail 1 and the slider 2 is not limited to two rows on one side, but may be one row on one side as in a second embodiment described later, or three or more rows. The cross-sectional shape of the raceway grooves 10, 11 may be an arc shape consisting of a single arc as described above, but may also be a substantially V-shape (Gothic arc-shaped groove) formed by combining two arcs with different centers of curvature.

[0023] Furthermore, the slider 2 is provided with return passages 14A, 14A, 14B, 14B (hereinafter, the reference numeral 14 may be used to refer to these collectively) which are through-holes with a substantially circular cross section that run parallel to the rolling passage 13 and penetrate the slider 2 in the longitudinal direction at the upper and lower parts of the thick portions of the left and right legs 6, 6 of the slider body 2A (see Figures 2 and 3).

[0024] The end cap 2B is made of, for example, a molded product of a resin material and has a generally U-shaped cross section similar to the slider body 2A. Furthermore, on both the left and right sides of the back surface of the end cap 2B (the surface that abuts against the slider body 2A), two arc-shaped, circular cross-sectional direction change paths 15 are formed (upper and lower) (see FIG. 3). When the end cap 2B is attached to the slider body 2A with fastening members such as screws, the direction change paths 15 connect the rolling path 13 and the return path 14. The cross-sectional shape of the direction change paths 15 is shown schematically in FIG. 3.

[0025] The return path 14 and the direction change paths 15 at both ends constitute a rolling element transport path 16 that transports and circulates the rolling elements 3 from the end point of the rolling path 13 to the start point, and the rolling path 13 and the rolling element transport path 16 constitute a substantially circular circulation path (see Figure 3). This substantially circular circulation path is formed in two levels, one above the other, on both the left and right sides of the guide rail 1.

[0026] When the slider 2 moves longitudinally along the guide rail 1, the rolling elements 3 loaded in the rolling path 13 move in the same direction as the slider 2 relative to the guide rail 1 while rolling within the rolling path 13. When the rolling elements 3 reach the end point of the rolling path 13, they are scooped up from the rolling path 13 and sent to the direction change path 15. Having entered the direction change path 15, the rolling elements 3 change direction and are introduced into the return path 14, and pass through the return path 14 to reach the opposite direction change path 15, where they change direction again and return to the start point of the rolling path 13. The rolling elements 3 repeat this circulation within the circulation path indefinitely, allowing the slider 2 to move smoothly along the guide rail 1.

[0027] Fig. 4 is a perspective view of the slider body 2A. Fig. 5 is an enlarged perspective view of part V in Fig. 4. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 4. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 4. Fig. 8 is an enlarged view of part VIII in Fig. 7.

[0028] The shapes of the ends of the raceway grooves 11A and 11B will be described with reference to the drawings. Hereinafter, raceway groove 11A will be described as an upper raceway groove, and raceway groove 11B will be described as a lower raceway groove. Furthermore, when simply referring to a "first raceway surface," this refers to at least one of a first upper raceway surface and a first lower raceway surface, which will be described later, and when simply referring to a "second raceway surface," this refers to at least one of a second upper raceway surface and a second lower raceway surface, which will be described later.

[0029] 5, the upper raceway groove 11A has a first upper raceway surface 11Aa on the center side of the slider body 2A and a second upper raceway surface 11Ab on the end side of the slider body 2A. The first upper raceway surface 11Aa and the second upper raceway surface 11Ab are each bounded by a vertical centerline C1 (an imaginary line) at the groove bottom. The portion above the vertical centerline C1 is called the upper flank, and the portion below the vertical centerline C1 is called the lower flank. The upper and lower flanks are symmetrical with respect to the vertical centerline C1. The vertical centerline C1 and the centerline O1 of the straight portion of the rolling path 13A are within the horizontal reference plane HP (FIG. 2).

[0030] The first upper raceway surface 11Aa has a uniform cross section perpendicular to the longitudinal direction. The center line of the cylindrical space formed by the first upper raceway surface 11Aa and the raceway groove 10A of the guide rail 1 is set to be the center line O1 of the straight portion of the rolling path 13A. In contrast, the second upper raceway surface 11Ab is formed so that the cross section perpendicular to the longitudinal direction varies partially.

[0031] The second upper track surface 11Ab has a first upper inclined surface 11Ac extending along the vertical centerline C1, a second upper inclined surface 11Ad formed above and in contact with the first upper inclined surface 11Ac, and a third upper inclined surface 11Ae formed below and in contact with the first upper inclined surface 11Ac. The first upper inclined surface 11Ac has a symmetrical shape with respect to the vertical centerline C1 (horizontal reference plane HP), and the second upper inclined surface 11Ad and the third upper inclined surface 11Ae each have a symmetrical shape with respect to the vertical centerline C1 (horizontal reference plane HP). Here, the term "first inclined surface" refers to at least one of the first upper inclined surface and the first lower inclined surface, the term "second inclined surface" refers to at least one of the second upper inclined surface and the second lower inclined surface, and the term "third inclined surface" refers to at least one of the third upper inclined surface and the third lower inclined surface.

[0032] As shown in Fig. 5, the first upper inclined surface 11Ac is connected to the first upper raceway surface 11Aa, but the second upper inclined surface 11Ad and the third upper inclined surface 11Ae are spaced apart (not continuous) from the first upper raceway surface 11Aa in the longitudinal direction. Specifically, the width of the first upper inclined surface 11Ac in a direction perpendicular to the vertical centerline C1 is uniform near the first upper raceway surface 11Aa and gradually narrows from the vicinity of the first upper raceway surface 11Aa toward the end of the slider body 2A, forming a tapered shape as viewed in Fig. 6. On the other hand, the second upper inclined surface 11Ad and the third upper inclined surface 11Ae are formed in a substantially triangular shape as viewed in Fig. 6, starting at a position a predetermined distance from the first upper raceway surface 11Aa and gradually widening in a direction perpendicular to the vertical centerline C1 toward the end of the slider body 2A.

[0033] 8, the first upper inclined surface 11Ac starts at a position a distance L1 from the end face (longitudinal end) 2Aa of the slider body 2A and terminates at the end face 2Aa. The distance L1 is the longitudinal length of the first upper inclined surface 11Ac. When the diameter of the rolling element 3 is Da, it is preferable that L1 = 1.0 × Da to 2.0 × Da.

[0034] The first upper inclined surface 11Ac has a first crowning shape that moves away from the center line O1 of the straight portion of the rolling path 13A (upward in FIG. 8 ) as it moves away from the first upper raceway surface 11Aa. The first crowning shape is an arc shape with a radius of curvature R1 in a cross section of FIG. 8 that includes the horizontal reference plane HP. In the cross section of FIG. 8 , a point P1 is defined as a point where a first vertical plane PL1 passing through a point on the first upper raceway surface 11Aa that is farthest from the center line O1 of the straight portion of the rolling path 13A intersects with a second vertical plane PL2 that intersects with the end face 2Aa, and a point P2 is defined as a point where the second vertical plane PL2 intersects with the first upper inclined surface 11Ac (here, on the intersection line between the end face 2Aa and the first upper inclined surface 11Ac). The distance between points P1 and P2 is defined as the drop amount d1 of the first crowning.

[0035] FIG. 9 is an enlarged view of section IX in FIG. 6 , showing a cross section including the vertical reference plane VP (i.e., the center line O1 of the straight portion is shifted perpendicular to the paper). The second upper inclined surface 11Ad begins at a position a distance L2 from the end face 2Aa of the slider body 2A and terminates at the end face 2Aa. When the longitudinal length of the first upper inclined surface 11Ac is L1, it is preferable that L1 > L2. If L2 is longer than L1, the load-bearing function of the upper raceway groove 11A and the crowning function of the first upper inclined surface 11Ac may be impaired. Furthermore, the axial depth of cut into the blank (material) of the slider body 2A during machining may increase. This raises concerns about increased lead time and increased load on the tool due to a reduced radial depth of cut. In contrast, by making L1>L2, the amount of axial cutting into the blank of the slider body 2A during machining can be reduced without interfering with the functions of the upper raceway groove 11A and the first upper inclined surface 11Ac.

[0036] 9, the second upper inclined surface 11Ad has a second crowning shape that moves away (upward in FIG. 9) from the center line O1 (horizontal reference plane HP) of the straight portion of the rolling path 13A as it moves away from the first upper raceway surface 11Aa. The second crowning shape is an arc shape with a curvature radius R2 in the cross section of FIG. 9, and it is preferable that R2<R1.

[0037] 9, the point where a first horizontal plane PM1 passing through a point on the first upper raceway surface 11Aa farthest from the center line O1 of the straight portion of the rolling path 13A intersects with a second vertical plane PL2 that intersects with the end face 2Aa is designated as P3, and the point where the second vertical plane PL2 intersects with the second upper inclined surface 11Ad (here, on the intersection line between the end face 2Aa and the second upper inclined surface 11Ad) is designated as P4. The distance between points P3 and P4 is designated as the drop amount d2 of the second crowning. The drop amount d2 of the second crowning can be determined depending on the maximum eccentricity e of the rolling element 3, which will be described later, but it is preferable that d2 be approximately equal to d1.

[0038] Here, if 1 / 2 of the inner diameter of the rolling path 13A is r and the distance between point P2 on the first upper inclined surface 11Ac and the center line O1 of the straight portion is D1 (FIG. 8), then D1 = d1 + r. If the distance between point P4 on the second upper inclined surface 11Ad and the horizontal reference plane HP including the center line O1 of the straight portion is D2 (FIG. 9), then D2 = d2 + r.

[0039] The shape of the third upper inclined surface 11Ae is the same as that of the second upper inclined surface 11Ad except that it is symmetrical with respect to the vertical center line C1, and therefore description thereof will be omitted.

[0040] 5, the lower raceway groove 11B has a first lower raceway surface 11Ba on the center side of the slider body 2A and a second lower raceway surface 11Bb on the end side of the slider body 2A, which are parallel to the upper raceway groove 11A. The first lower raceway surface 11Ba and the second lower raceway surface 11Bb are each bounded by a vertical centerline C2 (an imaginary line) at the groove bottom, with the portion above the vertical centerline C2 referred to as the upper flank and the portion below the vertical centerline C2 referred to as the lower flank. The upper flank and the lower flank are symmetrical with respect to the vertical centerline C2.

[0041] The first lower raceway surface 11Ba has a uniform cross section perpendicular to the longitudinal direction, whereas the second lower raceway surface 11Bb is formed so that the cross section perpendicular to the longitudinal direction varies from part to part.

[0042] The second lower raceway surface 11Bb has a first lower inclined surface 11Bc extending along the vertical centerline C2, a second lower inclined surface 11Bd formed above the first lower inclined surface 11Bc, and a third lower inclined surface 11Be formed below the first lower inclined surface 11Bc. The second lower inclined surface 11Bd and the third lower inclined surface 11Be are symmetrical with respect to the vertical centerline C2. The lower raceway groove 11B has a similar configuration to the upper raceway groove 11A, and therefore its description will be omitted. Furthermore, the shapes of the other ends of the upper raceway groove 11A and the lower raceway groove 11B are also similar to those described above, and therefore their description will be omitted.

[0043] (Operation and effect of this embodiment) Fig. 10 is a schematic diagram showing a cross section similar to Fig. 8 according to a comparative example, together with the rolling elements. Fig. 11 is a schematic diagram showing a cross section similar to Fig. 9 according to this embodiment, together with the rolling elements. Fig. 12 is a schematic diagram showing an enlarged view of part XII in Fig. 6 according to this embodiment, together with the rolling elements. Here, the explanation will be given using rolling passage 13A as an example, but the same applies to rolling passage 13B.

[0044] In contrast to this embodiment, the slider body of the comparative example does not have a second raceway surface, and the cylindrical first upper raceway surface 11Aa directly intersects with the end face 2Aa. Other configurations of the comparative example are the same as those of this embodiment.

[0045] For example, due to the influence of centrifugal force and vibrations when passing through the direction change path 15 (see FIG. 3 ) in the end cap 2B, the center of the rolling element 3 may be misaligned with the center line O1 of the straight portion of the rolling path 13A when it enters the rolling path 13A from the direction change path 15. In this case, the amount of misalignment between the center of the rolling element 3 and the center line O1 of the straight portion of the rolling path 13A is defined as the eccentricity e. Because the diameter of the rolling element 3 is slightly smaller than the diameter of the rolling path 13A, if the eccentricity e is smaller than half the diameter difference (diameter of the rolling path 13A - diameter of the rolling element 3), the rolling element 3 can smoothly enter the rolling path 13A. However, if the eccentricity e exceeds half the diameter difference, the rolling element 3 may collide with the edge of the rolling path 13A in the direction of entry, which may result in noise generation or damage to the rolling element 3.

[0046] 11, the first upper inclined surface 11Ac having the first crowning drop amount d1 is formed at the end of the rolling passage 13A in the approach direction. Therefore, even in a state where the rolling elements 3 are eccentric with an eccentricity amount e exceeding half of the diameter difference, the rolling elements 3 entering from the direction change passage 15 will come into oblique contact with the first upper inclined surface 11Ac having an outwardly convex shape with a curvature radius R1, and then roll and be guided to the first upper raceway surface 11Aa. This suppresses large changes in Hertzian stress, thereby suppressing noise generation and damage to the rolling elements 3 and ensuring smooth movement of the rolling elements 3.

[0047] 12, there are also cases where an eccentric rolling element 3 with an eccentricity amount e exceeding half of the diameter difference enters. In such cases, the smooth entry of the rolling element 3 may be hindered by the first upper inclined surface 11Ac alone. In contrast, in this embodiment, the second upper inclined surface 11Ad and the third upper inclined surface 11Ae, each having a second crowning drop amount d2, are formed above and below the first upper inclined surface 11Ac near the end of the second upper raceway surface 11Ab in the entry direction.

[0048] Therefore, even when a rolling element 3 that is eccentric in the vertical direction by a relatively large eccentricity amount e enters, it will roll after coming into oblique contact with the second upper inclined surface 11Ad or the third upper inclined surface 11Ae, which have an outwardly convex shape with a curvature radius R2, and then be guided from the first upper inclined surface 11Ac to the first upper raceway surface 11Aa. This reduces the impact force on the slider body 2A, making it possible to suppress noise generation and damage to the rolling element 3.

[0049] The lower raceway groove 11B has the same configuration as the upper raceway groove 11A, and therefore exerts the same effects.

[0050] (Method for machining first upper raceway surface and second upper raceway surface) Next, a method for machining the first upper raceway surface 11Aa and the second upper raceway surface 11Ab will be described. Fig. 13 is a schematic diagram showing a part of the end surface 2Aa of the blank (material) of the slider body 2A as viewed from the longitudinal direction, and a grinding tool TL. Fig. 14 is a schematic diagram showing the cross section of Fig. 6 and the grinding tool TL. Fig. 15 is a schematic diagram showing the trajectory of a part of the grinding tool TL.

[0051] 13 to 15, the longitudinal direction of the slider body 2A is the Y direction, the width direction of the slider body 2A is the X direction, and the up-down direction is the Z direction.

[0052] The grinding tool TL is composed of a pair of parallel annular grinding wheels TL2, TL2 and a cylindrical portion TL1 that coaxially holds the grinding wheels TL2, TL2. When the grinding tool TL is cut along a plane passing through the center line RO of the grinding tool TL, the grinding wheels TL2, TL2 have the same semicircular outer circumferential surface as the upper raceway groove 11A and the lower raceway groove 11B.

[0053] When grinding the first upper raceway surface 11Aa and the first lower raceway surface 11Ba, first, grooves similar to the first upper raceway surface 11Aa and the first lower raceway surface 11Ba are formed in a blank of the slider body 2A by cutting or the like. Then, while aligning the center line RO of the grinding tool TL with the Z direction, the grinding tool TL, which rotates around the center line RO, is translated in the X direction toward the inside of the leg portion 6, and grinding of the inner surface of the groove is started with the outer peripheral surfaces of the grinding wheels TL2, TL2, and then the grinding tool TL is moved in the Y direction. In this way, the first upper raceway surface 11Aa and the first lower raceway surface 11Ba are formed.

[0054] After forming the first upper raceway surface 11Aa and the first lower raceway surface 11Ba, the first upper inclined surface 11Ac and the first lower inclined surface 11Bc are machined and formed. Specifically, while rotating the grinding tool TL, the grinding tool TL is translated in the Y and X directions so that the center line RO of the grinding tool TL approaches the width direction end of the blank of the slider body 2A as it approaches the end face 2Aa of the slider body 2A. At this time, it is preferable that the trajectory of the center line RO of the grinding tool TL coincides with the arc shape of the curvature radius R1 shown in FIG. 8. As a result, the first upper inclined surface 11Ac shown in FIG. 8 is ground, and simultaneously the first lower inclined surface 11Bc is ground.

[0055] Then, the second upper inclined surface 11Ad and the second lower inclined surface 11Bd are machined and formed. Specifically, the grinding tool TL is rotated about the center line RO from an initial position where it intersects with the end face 2Aa, while the grinding tool TL is translated upward in the Z direction, as shown in FIG. 15(a). Then, as shown in FIG. 15(b), the grinding tool TL is translated in the Y and X directions as it approaches the first upper raceway surface 11Aa and the first lower raceway surface 11Ba from the end face 2Aa of the slider body 2A, so that the center line RO of the grinding tool TL moves away from the widthwise end of the blank of the slider body 2A. When the grinding tool TL reaches a position a distance L2 away from the end face 2Aa, the grinding wheels TL2, TL2 are separated from the blank of the slider body 2A. At this time, it is preferable that the trajectory of the center line RO of the grinding tool TL conform to the arc shape with a radius of curvature R2 shown in FIG. 9. As a result, the second upper inclined surface 11Ad shown in FIG. 9 is ground, and at the same time, the second lower inclined surface 11Bd is ground.

[0056] Furthermore, the third upper inclined surface 11Ae and the third lower inclined surface 11Be are machined and formed. Specifically, the grinding tool TL is returned to its initial position and rotated about the center line RO while being translated downward in the Z direction, as shown in FIG. 15( a). Then, as shown in FIG. 15( b), the grinding tool TL is translated in the Y and X directions so that the center line RO of the grinding tool TL moves away from the first upper raceway surface 11Aa and the first lower raceway surface 11Ba as it approaches the end face 2Aa of the slider body 2A. When the grinding tool TL reaches a position a distance L2 away from the end face 2Aa, the grinding wheels TL2, TL2 are separated from the blank of the slider body 2A. At this time, it is preferable that the trajectory of the center line RO of the grinding tool TL conform to the arc shape of a radius of curvature R2 shown in FIG. 9. 9 is ground, and at the same time, the third lower inclined surface 11Be is ground. Furthermore, since the processing of the other ends of the upper raceway groove 11A and the lower raceway groove 11B is similar to that described above, a description thereof will be omitted.

[0057] In this embodiment, the upper raceway groove 11A and the lower raceway groove 11B are formed by machining simultaneously, but they may be formed by machining separately.

[0058] According to this embodiment, by forming a second crowning shape in the track grooves 11A, 11B of the slider body 2A, a sufficient drop amount can be ensured in a direction different from that of the first crowning shape, so that smooth movement can be ensured even if the rolling body 3 enters the rolling passages 13A, 13B eccentrically.

[0059] In addition, since the rolling elements 3 can be prevented from colliding with the edges at the ends of the rolling passages 13A and 13B, the increase in collision pressure when the rolling elements 3 enter the rolling passages 13A and 13B can be suppressed.

[0060] Furthermore, the second upper inclined surface 11Ad and the second lower inclined surface 11Bd, and the third upper inclined surface 11Ae and the third lower inclined surface 11Be can be machined and formed by adding a movement direction to the grinding tool TL that forms the first upper inclined surface 11Ac and the first lower inclined surface 11Bc, so that they are easy to machine and do not significantly increase costs.

[0061] In addition, by forming a second crowning shape that increases the amount of clearance from the center line of the rolling passages 13A and 13B, the tolerance range for installation errors of the circulating parts that correspond to the eccentricity of the rolling body 3 is expanded, so that processing errors of the surface that serves as the reference for positioning the circulating parts provided on the slider main body 2A can be tolerated, making it possible to reduce costs.

[0062] (Variant 1) Figure 16 is a cross-sectional view similar to Figure 8 showing variant 1 of the first embodiment, and Figure 17 is a cross-sectional view similar to Figure 9 showing variant 1 of the first embodiment, showing a cross section including the vertical reference plane VP.

[0063] The upper raceway groove 11A in the first modification has a first upper raceway surface 11Aa on the central side of the slider body 2A and a second upper raceway surface 11Ab' on the end side of the slider body 2A.

[0064] The second upper track surface 11Ab' has a first upper inclined surface 11Ac', a second upper inclined surface 11Ad' formed upward on the end side of the first upper inclined surface 11Ac', and a third upper inclined surface 11Ae' formed downward on the end side of the first upper inclined surface 11Ac'.

[0065] The first upper inclined surface 11Ac' has a first tapered shape (a crowning shape whose cross section is linear) that moves away from the center line O1 of the linear portion of the rolling path 13A (upward in FIG. 16 ) as it moves away from the first upper raceway surface 11Aa. The first upper inclined surface 11Ac' has a first crowning drop amount d1.

[0066] The second upper inclined surface 11Ad' starts at a position a distance L2 from the end surface 2Aa of the slider body 2A and terminates at the end surface 2Aa. If the distance L1 is the longitudinal length of the first upper inclined surface 11Ac', L1>L2.

[0067] The second upper inclined surface 11Ad' has a second tapered shape (a crowning shape with a linear cross section) that moves away from the center line O1 (horizontal reference plane HP) of the linear portion of the rolling path 13A (upward in FIG. 17 ) as it moves away from the first upper raceway surface 11Aa. The second upper inclined surface 11Ad' also has a second crowning drop d2. It is preferable that d2≈d1.

[0068] That is, the surface of the first upper inclined surface 11Ac' in the cross section of Figure 16 (intersection with the horizontal reference plane HP) is linear, and the surfaces of the second upper inclined surface 11Ad' and the third upper inclined surface 11Ae' in the cross section of Figure 17 (intersection with the vertical reference plane VP) are also linear.

[0069] The shape of the third upper inclined surface 11Ae' is the same as the shape of the second upper inclined surface 11Ad' except that they are symmetrical, and the shape of the second lower raceway surface (not shown) is also the same as the second upper raceway surface 11Ab', so descriptions of these will be omitted. Furthermore, the configuration other than the second upper raceway surface 11Ab' and the second lower raceway surface is the same as in the first embodiment, so redundant descriptions will be omitted.

[0070] 18 is a cross-sectional view similar to FIG. 9 showing a second modification of the first embodiment, and shows a cross section including the vertical reference plane VP. The upper raceway groove 11A in the second modification has a first upper raceway surface 11Aa on the central side of the slider body 2A and a second upper raceway surface 11Ab″ on the end side of the slider body 2A.

[0071] The second upper orbital surface 11Ab" has a first upper inclined surface 11Ac, a second upper inclined surface 11Ad formed upward on the end side of the first upper inclined surface 11Ac, and a third upper inclined surface 11Ae formed downward on the end side of the first upper inclined surface 11Ac. The second upper inclined surface 11Ad and the third upper inclined surface 11Ae extend from a position spaced apart from the first upper orbital surface 11Aa to the vicinity of the end face 2Aa of the slider body 2A.

[0072] Furthermore, a fourth upper inclined surface 11Af is formed between the second upper inclined surface 11Ad and the end face 2Aa of the slider body 2A. The fourth upper inclined surface 11Af is tapered away from the center line O1 of the straight portion of the rolling path 13A (upward in FIG. 18 ) as it moves away from the first upper raceway surface 11Aa. A fifth upper inclined surface 11Ag is tapered away from the center line O1 of the straight portion of the rolling path 13A (downward in FIG. 18 ) as it moves away from the first upper raceway surface 11Aa. Here, the term “fourth inclined surface” refers to at least one of the fourth upper inclined surface and the fourth lower inclined surface, and the term “fifth inclined surface” refers to at least one of the fifth upper inclined surface and the fifth lower inclined surface.

[0073] In the cross section of FIG. 18, the surfaces of the fourth upper inclined surface 11Af and the fifth upper inclined surface 11Ag (intersections with the vertical reference plane VP) are linear.

[0074] In the cross section of Figure 18, the inclination angle θ of the surfaces of the fourth upper inclined surface 11Af and the fifth upper inclined surface 11Ag (intersections with the vertical reference plane VP) relative to the center line O1 of the straight portion of the rolling passage 13A is preferably 15 to 50 degrees, and more preferably 45 degrees.

[0075] According to this modification, the distance between point P5 where end face 2Aa of slider body 2A intersects with fourth upper inclined surface 11Af and fifth upper inclined surface 11Ag and point P4 where end face 2Aa intersects with second upper inclined surface 11Ad and third upper inclined surface 11Ae is d3 in the case where fourth upper inclined surface 11Af and fifth upper inclined surface 11Ag are not present (first embodiment shown by chain lines in FIG. 18 ). Therefore, by forming fourth upper inclined surface 11Af and fifth upper inclined surface 11Ag between the ends of second upper inclined surface 11Ad and third upper inclined surface 11Ae and end face 2Aa of slider body 2A, it is possible to further ensure drop d3, thereby enabling rolling element 3 to smoothly enter the return passage even when eccentricity e of rolling element 3 increases. The configuration other than the fourth upper inclined surface 11Af and the fifth upper inclined surface 11Ag is the same as that of the first embodiment, and therefore a duplicated description will be omitted.

[0076] Second Embodiment Figure 19 is a cross-sectional view similar to Figure 2 of a slider body 2A' according to a second embodiment. This embodiment has only the raceway grooves 11A, 11A of the rolling paths 13A, 13A, and the shape of the guide rail (not shown) is accordingly different. The rest of the configuration is the same as in the first embodiment, including the shape of the raceway grooves 11A, 11A, so a duplicated description will be omitted.

[0077] The present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0078] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0079] This application is based on a Japanese patent application (Patent Application No. 2023-223378) filed on December 28, 2023, the contents of which are incorporated herein by reference.

[0080] REFERENCE SIGNS LIST 1 guide rail 2 slider 2A slider body 2B end cap 3 rolling element 4 cage 10A, 10B raceway groove 11A, 11A raceway groove 13A, 13B rolling path 14A, 14B return path 15 direction change path

Claims

1. A linear guide device comprising a guide rail, a slider arranged to move relative to the guide rail in the longitudinal direction, and a plurality of rolling elements arranged to be rollable along a rolling path formed between the guide rail and the slider, wherein the slider includes a slider body having a raceway groove facing the raceway groove of the guide rail to form the rolling path of the rolling elements and a return path for the rolling elements, and an end cap having a direction-changing path connecting the return path and the rolling path, the raceway groove of the slider body has a first raceway surface on the central portion side of the rolling path and a second raceway surface on the end portion side of the rolling path, the second raceway surface has a first inclined surface extending from the first raceway surface to the end surface of the slider body, and a second inclined surface and a third inclined surface extending to the end surface of the slider body or the vicinity thereof without being continuous with the first raceway surface, when a plane passing through the center in the width direction of the slider body and the longitudinal axis of the guide rail is defined as a vertical center plane CP, a plane perpendicular to the vertical center plane CP and passing through the center line of the straight portion of the rolling path is defined as a horizontal reference plane HP, and a plane parallel to the vertical center plane CP and intersecting the second inclined surface and the third inclined surface is defined as a vertical reference plane VP, a point P2 on the first inclined surface farthest from the vertical reference plane VP is spaced from the vertical reference plane VP more than a point P1 on the first raceway surface farthest from the vertical reference plane VP, and a point P4 on the second inclined surface and the third inclined surface farthest from the horizontal reference plane HP is spaced from the horizontal reference plane HP more than a point P3 on the first raceway surface farthest from the horizontal reference plane HP.

2. The linear guide device according to claim 1, wherein the point P2 on the first inclined surface farthest from the vertical reference plane VP is located on the intersection line between the end surface of the slider body and the first inclined surface, and the first inclined surface is spaced from the vertical reference plane VP as it approaches the end surface of the slider body.

3. The point P4 on the second inclined surface and the third inclined surface that is farthest from the horizontal reference plane HP is located at the intersection of the end face of the slider body and the second inclined surface and the third inclined surface. The second inclined surface and the third inclined surface are spaced apart from the horizontal reference plane HP as they approach the end face of the slider body. The linear motion guiding device according to claim 2, characterized in that.

4. The cross-sectional shape of the first inclined surface obtained by cutting with the horizontal reference plane HP has an arc shape with a radius of curvature R1. The cross-sectional shapes of the second inclined surface and the third inclined surface obtained by cutting with the vertical reference plane VP have an arc shape with a radius of curvature R2, and R2 < R1. The linear motion guiding device according to claim 3, characterized in that.

5. The intersection of the surface of the first inclined surface intersecting the horizontal reference plane HP is linear. The intersection of the surfaces of the second inclined surface and the third inclined surface intersecting the vertical reference plane VP is linear. The linear motion guiding device according to claim 3, characterized in that.

6. A fourth inclined surface is formed between the end face of the slider body and the second inclined surface, and a fifth inclined surface is formed between the end face of the slider body and the third inclined surface. The intersection of the surfaces of the fourth inclined surface and the fifth inclined surface intersecting the vertical reference plane VP is linear. The linear motion guiding device according to claim 1, characterized in that.

7. The inclination angle θ between the intersection of the surfaces of the fourth inclined surface and the fifth inclined surface intersecting the vertical reference plane VP and the vertical reference plane VP is 15 degrees to 50 degrees. The linear motion guiding device according to claim 6, characterized in that.

8. The second inclined surface and the third inclined surface have a symmetrical shape with the horizontal reference plane HP interposed therebetween. The linear motion guiding device according to any one of claims 1 to 7, characterized in that.

9. A method for manufacturing a linear guide device including a guide rail, a slider arranged to move relative to the guide rail in the longitudinal direction, and a plurality of rolling elements arranged to roll along a rolling path formed between the guide rail and the slider, wherein the slider includes a slider body having a raceway groove facing the raceway groove of the guide rail to form the rolling path of the rolling elements and a return path for the rolling elements, and an end cap having a direction-changing path connecting the return path and the rolling path, the raceway groove of the slider body has a first raceway surface on the central portion side of the rolling path and a second raceway surface on the end portion side of the rolling path, the second raceway surface has a first inclined surface extending from the first raceway surface to the end face of the slider body, and a second inclined surface and a third inclined surface extending to the end face of the slider body or its vicinity without being continuous with the first raceway surface, the slider body has a body portion and a pair of leg portions arranged at both ends in the width direction of the body portion, when the width direction of the slider body is the X direction, the longitudinal direction of the slider body is the Y direction, and the direction orthogonal to the X direction and the Y direction is the Z direction, a step of forming the first raceway surface by bringing a tool having an annular grinding wheel and rotating around a rotation axis RO into contact with the central portion in the longitudinal direction of the opposing side surfaces of the leg portions of the slider body and moving the tool in the Y direction toward the longitudinal end of the slider body; a step of forming the first inclined surface of the second raceway surface by moving the tool in the Y direction and the X direction so as to approach the width end of the slider body as the tool approaches the longitudinal end of the slider body; and a step of forming a part of the second inclined surface and the third inclined surface by moving the tool in the Z direction after the tool reaches the longitudinal end of the slider body. A method for manufacturing a linear guide device, characterized by the above.

10. After moving the tool in the Z direction, a step of forming the remainder of the second inclined surface and the third inclined surface by moving the tool in the X direction and the Y direction toward the central portion of the slider body so as to move away from the width end of the slider body as the tool moves away from the longitudinal end of the slider body. A method for manufacturing a linear guide device according to claim 9, characterized by the above.

11. The method for manufacturing a linear guide device according to claim 9 or 10, characterized in that the tool has a pair of the annular grinding wheels coaxially.

Images