Linear motion guiding device and its manufacturing method

Abstract

In this linear motion guiding device, the track surface has: an end-side track surface that intersects the longitudinal end face of the slider body; and an inner-side track surface disposed on the opposite side of the longitudinal end face, separated from the end-side track surface. The end-side track surface has a rotationally symmetric shape with reference to the central axis of the end-side track surface, which is aligned with or parallel to the center line of the straight section of the rolling channel. It also has: a partially conical track surface connected to the inner-side track surface; and a curved track surface connecting the partially conical track surface to the longitudinal end face. In a cross-section including the central axis of the end-side track surface, the surface of the partially conical track surface is straight, and the surface of the curved track surface is arc-shaped. In the cross-section, the tangent of the partially conical track surface at the boundary between the partially conical track surface and the curved track surface is common to both.

Description

Technical Field

[0001] This invention relates to a linear motion guiding device and its manufacturing method. Background Technology

[0002] A linear motion guiding device, which guides an object in a straight line while continuously circulating rolling elements such as rollers and balls inside, is one of the important mechanical elements that has a significant impact on the motion accuracy of semiconductor manufacturing equipment, ultra-precision machining machinery, and ultra-precision measuring equipment.

[0003] The linear motion guiding device includes: a guide rail having a guide rail-side rolling element track groove; and a slider body having a slider-side rolling element track groove opposite to the guide rail-side rolling element track groove, and being supported by the guide rail in a manner that allows axial movement via the rolling of multiple rolling elements, wherein the multiple rolling elements are disposed within a rolling channel formed between the slider-side rolling element track groove and the guide rail-side rolling element track groove. The linear motion guiding device further includes: a rolling element return channel disposed within the slider body in a manner substantially parallel to the rolling channel; and a direction conversion path consisting of end caps mounted at both ends of the slider body in the direction of movement, connecting the rolling channel to the rolling element return channel.

[0004] When the rolling elements of a linear motion guide device cycle infinitely in the rolling channel, direction switching path, and rolling element return path, periodic micro-vibrations (hereinafter referred to as rolling element passing vibrations) are generated, which significantly affect the motion accuracy of the aforementioned equipment. Rolling element passing vibrations occur when a rolling element, while bearing a load due to preload or external load, rolls in the rolling channel (load area) and the load is released when it enters the rolling element circulation path (unload area), or conversely, when it newly bears a load while entering the load area from the unload area.

[0005] To suppress rolling element vibration, inclined surfaces, known as convex surfaces, are provided at both ends of the rolling element track groove on the slider side that forms the rolling channel. The convex surfaces smoothly handle load variations that occur as the rolling element enters and exits the load area, thereby reducing rolling element vibration.

[0006] Patent Document 1 discloses a linear motion guide bearing. The linear motion guide bearing has an inclined portion at both ends of the slider-side rolling element track groove formed by a first convex surface with a curved shape, a second convex surface adjacent to the first convex surface, and an inclined surface disposed between the second convex surface and the end face of the slider body. The first convex surface is formed with a large radius of curvature in a continuous and gently inclined manner from the slider-side rolling element track groove. The inclination of the second convex surface is steeper than that of the first convex surface extending to the inner circumferential surface of the direction conversion path and shorter than the axial length of the first convex surface. The inclined surface is more inclined than the first convex surface and the second convex surface.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2008-133837 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] However, ball eccentricity, a phenomenon known as ball offset, where the ball's center deviates from the centerline of the return channel when it enters the rolling channel, sometimes becomes a problem. According to the technology in Patent Document 1, by combining a first convex surface with a second convex surface, sufficient downward displacement can be created in the groove bottom direction (width direction of the slider) to release ball eccentricity. However, for ball eccentricity in the direction away from the groove bottom, particularly in the direction perpendicular to the groove bottom (vertical direction of the slider), since there is no way to provide a clearance space at the end of the slider groove, the ball violently collides with the end face of the slider, potentially deteriorating durability.

[0012] The present invention was made in view of the above-mentioned problems, and its object is to provide a linear motion guiding device and a method for manufacturing the same, which can mitigate the impact force and ensure the smooth movement of the balls regardless of the movement of the balls entering the track surface.

[0013] Technical means for solving problems

[0014] The linear motion guiding device of the present invention is characterized by having:

[0015] guide;

[0016] A slider, the slider being configured to move relative to a guide rail in the length direction; and

[0017] A plurality of rolling elements, wherein the plurality of rolling elements are configured to roll freely along a rolling channel formed between the guide rail and the slider.

[0018] The slider has:

[0019] A slider body, the slider body having a track surface that is disposed opposite to the track groove of the guide rail and forms a rolling channel for the rolling element, and a return channel for the rolling element; and

[0020] End cap, the end cap having a direction conversion path connecting the return channel and the rolling channel,

[0021] The track surface has: an end-side track surface that intersects the longitudinal end face of the slider body; and an inner-side track surface that is disposed on the opposite side of the longitudinal end face, separated from the end-side track surface.

[0022] The end-side track surface is a rotationally symmetric shape with reference to a central axis of the end-side track surface that is aligned with or parallel to the center line of the straight section of the rolling channel, and has: a partially conical track surface connected to the inner side track surface; and a curved track surface connecting the partially conical track surface to the longitudinal end face.

[0023] In a cross-section including the central axis of the end-side track surface, the surface of the partially conical track surface is straight, and the surface of the curved track surface is arc-shaped.

[0024] In the cross-section, the tangents of the partial conical track surface and the curved track surface at the boundary between the partial conical track surface and the curved track surface are common.

[0025] The present invention provides a method for manufacturing a linear motion guiding device, wherein the linear motion guiding device comprises:

[0026] guide;

[0027] A slider, the slider being configured to move relative to a guide rail in the length direction; and

[0028] A plurality of rolling elements, wherein the plurality of rolling elements are configured to roll freely along a rolling channel formed between the guide rail and the slider.

[0029] The slider has:

[0030] A slider body, the slider body having a track surface that is disposed opposite to the track groove of the guide rail and forms a rolling channel for the rolling element, and a return channel for the rolling element; and

[0031] End cap, the end cap having a direction conversion path connecting the return channel and the rolling channel,

[0032] The track surface has: an end-side track surface that intersects the longitudinal end face of the slider body; and an inner-side track surface that is disposed on the opposite side of the longitudinal end face, separated from the end-side track surface.

[0033] The end-side track surface is a rotationally symmetric shape with reference to a central axis of the end-side track surface that is aligned with or parallel to the center line of the straight section of the rolling channel, and has: a partially conical track surface connected to the inner side track surface; and a curved track surface connecting the partially conical track surface to the longitudinal end face.

[0034] In the manufacturing method of this linear motion guide device

[0035] When the width direction of the slider body is defined as the X direction, the length direction of the slider body is defined as the Y direction, and the direction orthogonal to the X and Y directions is defined as the Z direction,

[0036] The first tool rotates about a rotation axis parallel to the Z direction while moving parallel to the slider body along the Y direction, thereby forming the inner side track surface.

[0037] The second tool rotates about a rotation axis parallel to the center line of the straight section of the rolling channel while moving parallel to the slider body in the X direction, thereby forming the end side track surface.

[0038] In a cross-section including the central axis of the end-side track surface, the surface of the partially conical track surface is formed as a straight line, and the surface of the curved track surface is formed as an arc.

[0039] In the cross-section, the tangents of the partial conical track surface and the curved track surface at the boundary between the partial conical track surface and the curved track surface are common.

[0040] Invention Effects

[0041] According to the present invention, a linear motion guiding device and its manufacturing method can be provided, which can mitigate the impact force and ensure the smooth movement of the balls regardless of the movement of the balls entering the track surface. Attached Figure Description

[0042] Figure 1 This is a perspective view showing a linear motion guiding device according to a first embodiment of the present invention.

[0043] Figure 2 Viewed from the length of the guide rail Figure 1 The front view of the slider body of the linear motion guide device.

[0044] Figure 3 yes Figure 2 Sectional view III-III.

[0045] Figure 4 This is a perspective view showing the end of the slider body.

[0046] Figure 5 yes Figure 4 The VV sectional view is an enlarged view showing a portion of the slider body.

[0047] Figure 6 Viewed from the direction of arrow VI Figure 5 The image shows the main body of the slider.

[0048] Figure 7 yes Figure 6 Sectional view VII-VII.

[0049] Figure 8 yes Figure 6 Side view of VIII-VIII.

[0050] Figure 9 This involves comparing the examples with... Figure 8 A schematic diagram showing the same side along with the rolling element.

[0051] Figure 10 This implementation method involves the following: Figure 8 A schematic diagram showing the same side along with the rolling element.

[0052] Figure 11 This implementation method involves the following: Figure 8 A schematic diagram showing the same side along with the rolling element.

[0053] Figure 12 This is a schematic diagram showing a portion of the blank of the slider body as viewed from the orthogonal direction of length and the cutting tool.

[0054] Figure 13 This is a schematic diagram showing the blank and grinding tool of the slider body as viewed from the length direction.

[0055] Figure 14 It will be with Figure 7 An enlarged schematic diagram showing the same cross-section along with the rolling element.

[0056] Figure 15 This is a graph showing the results of numerical calculations (based on elastic contact theory) of the contact pressure caused by the collision when the tilt angle of the third upper track surface is changed.

[0057] Figure 16 It will be with Figure 7 An enlarged schematic diagram showing the same cross-section along with the rolling element.

[0058] Figure 17 This is a figure showing the results of numerical calculations (based on elastic contact theory) of the contact pressure caused by the collision with a change in the radius of curvature of the profile of the fourth upper track surface.

[0059] Figure 18 This is an enlarged view of the end of Embodiment 1, which is equivalent to this embodiment. Figure 7 The same sectional view.

[0060] Figure 19 This is an enlarged view of the end of Comparative Example 1. Figure 7 The same sectional view.

[0061] Figure 20 This is an enlarged view of the end of Comparative Example 2. Figure 7 The same sectional view.

[0062] Figure 21 This is an enlarged view of the end of Comparative Example 3. Figure 7 The same sectional view.

[0063] Figure 22 The slider body involved in the second embodiment is related to... Figure 8 The same side view. Detailed Implementation

[0064] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification, unless otherwise specified, directional terms (above, below, etc.) refer to... Figure 2 In each direction. Additionally, "length direction" refers to the length direction of the guide rail or slider.

[0065] (First Implementation)

[0066] Figure 1 This is a perspective view showing a linear motion guiding device according to a first embodiment of the present invention. Figure 2 Viewed from the length of the guide rail Figure 1 The front view of the slider body of the linear motion guide device is shown, but the end cap is omitted. Figure 3 yes Figure 2 Sectional view III-III, but retainer 4 and retainer groove 10Ba are omitted from the drawing. Figure 2 In this design, the plane passing through the width center of the slider body 2A and the length axis of the guide rail 1 is designated as the vertical center plane CP. The plane orthogonal to the vertical center plane CP and passing through the center line O1 of the straight section of a pair of rolling channels 13A positioned on either side of the guide rail 1 is designated as the horizontal reference plane HP. Furthermore, the plane passing through the center line O1 of the straight section of the rolling channel 13A and orthogonal to the horizontal reference plane HP is designated as the vertical reference plane VP. Details will be described later; the structure of each part will be explained using the vertical reference plane VP and the horizontal reference plane HP corresponding to one rolling channel 13A.

[0067] Along a guide rail 1 that extends in a straight line and has a roughly rectangular cross-sectional shape, a slider 2 with a roughly U-shaped cross-sectional shape is assembled in such a way that it can move along the length of the guide rail 1. On the left and right sides 1a, 1a intersecting the upper surface 1b in the width direction of the guide rail 1, track grooves 10A, 10A are formed along the length direction. The track grooves 10A, 10A are formed by grooves with a cross-sectional shape of approximately 1 / 4 circular arc.

[0068] Furthermore, on the left and right sides 1a, 1a in the width direction of the guide rail 1, approximately at the center in the vertical direction, track grooves 10B, 10B are formed along the length direction. The track grooves 10B, 10B are formed by grooves with a cross-sectional shape that is approximately semi-circular. Moreover, at the bottom of the track grooves 10B, 10B, a retainer groove 10Ba (line groove) is formed along the length direction between the two ends of the moving area of ​​the slider 2 (for example, between the two ends of the guide rail 1 in the length direction). The retainer groove 10Ba accommodates a part of the retainer 4 and guides the retainer 4 when the slider 2 moves. The cross-sectional shape of the retainer groove 10Ba is, for example, approximately rectangular.

[0069] Furthermore, the slider 2 consists of a flat main body 7 facing the upper surface 1b of the guide rail 1 and two legs 6, 6 extending downward from the left and right sides of the main body 7 and facing the side 1a respectively. The angle between the main body 7 and the legs 6, 6 is approximately right angle, so the cross-sectional shape of the slider 2 is approximately U-shaped. Moreover, the slider 2 is movably mounted relative to the guide rail 1 such that the guide rail 1 is sandwiched between the two legs 6, 6.

[0070] The slider 2 includes a slider body 2A and end caps 2B, 2B detachably mounted at both ends (both ends in the longitudinal direction) of the slider body 2A. Side seals 5, 5 are installed at both ends of the slider 2 (the outer end faces of each end cap 2B in the longitudinal direction). These side seals 5, 5 slide in contact with the outer surfaces (upper surface 1b and side surfaces 1a, 1a) of the guide rail 1, sealing the portion of the opening between the guide rail 1 and the slider 2 facing the longitudinal end face. Lower seals 8, 8 are installed at the bottom of the slider 2, sealing the portion of the opening between the guide rail 1 and the slider 2 facing the lower surface of the slider 2. These side seals 5, 5 and lower seals 8, 8 prevent foreign objects from entering the gap from the outside and prevent lubricant from leaking out of the gap.

[0071] Furthermore, track grooves 11A, 11A, 11B, 11B (hereinafter, sometimes referred to as 11 as their collective reference numeral) are formed at the corners of the inner sides of the left and right legs 6, 6 of the slider body 2A and approximately at the center in the vertical direction. These track grooves 11A, 11A, 11B, 11B are formed by grooves with a roughly semi-circular cross-sectional shape that are opposite to the track grooves 10A, 10A, 10B, 10B (hereinafter, sometimes referred to as 10 as their collective reference numeral) of the guide rail 1. In addition, rolling channels 13A, 13A, 13B, 13B (hereinafter, sometimes referred to as 13 as their collective reference numeral) with a roughly circular cross-section are formed between the track groove 10 of the guide rail 1 and the track groove 11 of the slider 2, and these rolling channels extend along the length direction.

[0072] Within the rolling channel 13, a plurality of rolling elements 3 (balls) are held by a retainer 4 and are loaded with free rolling action. Through the rolling of the rolling elements 3 within the rolling channel 13, the slider 2 is guided by the guide rail 1 and can move along its length. The retainer 4 is formed, for example, of metal wire, and is used to hold the rolling elements 3 in order to prevent them from falling off the slider 2 mounted before the guide rail 1.

[0073] Furthermore, the number of track grooves 10 and 11 provided by the guide rail 1 and the slider 2 is not limited to two rows on one side. For example, it can also be one row or more rows on one side, as described in the second embodiment below. In addition, the cross-sectional shape of the track grooves 10 and 11 can be an arc shape composed of a single arc as described above, or it can be a roughly V-shaped (Gothic arc-shaped groove) formed by combining two arcs with different centers of curvature.

[0074] Furthermore, the slider 2 has return channels 14A, 14A, 14B, 14B (hereinafter, 14 is sometimes used as a reference numeral for them) on the upper and lower parts of the wall thickness of the left and right legs 6, 6 of the slider body 2A. These return channels 14A, 14A, 14B, 14B are formed by through holes with a generally circular cross-sectional shape that extend along the length direction parallel to the rolling channel 13 (see reference). Figure 2 , Figure 3 ).

[0075] The end cap 2B is, for example, a molded product made of resin material, and like the slider body 2A, its cross-sectional shape is roughly U-shaped. Furthermore, on the left and right sides of the back surface of the end cap 2B (the contact surface that abuts against the slider body 2A), the direction conversion path 15, with a circular cross-sectional shape and curved into an arc, is formed in two layers (see reference). Figure 3 When the end cap 2B is installed on the slider body 2A using screws or other fasteners, the rolling channel 13 is connected to the return channel 14 via the direction conversion path 15. Furthermore, the cross-sectional shape of the direction conversion path 15 is... Figure 3 It is shown schematically in the diagram.

[0076] These return channels 14 and the direction conversion paths 15 at both ends constitute a rolling element transport path 16 that transports the rolling element 3 from the end point of the rolling channel 13 to the starting point and circulates it. The rolling channel 13 and the rolling element transport path 16 form a roughly circular circulation path (see reference). Figure 3 The roughly circular loop path is formed on the left and right sides, separated by guide rail 1.

[0077] As slider 2 moves along guide rail 1 in the longitudinal direction, rolling element 3, loaded in rolling channel 13, rolls within the channel while moving relative to guide rail 1 in the same direction as slider 2. When rolling element 3 reaches the end of rolling channel 13, it is scooped up and transported to direction change path 15. After entering direction change path 15, rolling element 3 changes direction and is guided into return channel 14, then through return channel 14 to the opposite direction change path 15, where it changes direction again and returns to the starting point of rolling channel 13. This cycle is repeated infinitely by rolling element 3, allowing slider 2 to move smoothly along guide rail 1.

[0078] Figure 4 This is a perspective view showing the end of the slider body 2A. Figure 5 yes Figure 4 The VV sectional view is shown in an enlarged form. Figure 6 Observe along the direction of arrow VI Figure 5 Figure 2A shows the slider body. Figure 7 yes Figure 6 Sectional view VII-VII. Figure 8 yes Figure 6 Side view of VIII-VIII.

[0079] Referring to the accompanying drawings, the end shape of track groove 11A will be described. Hereinafter, track groove 11A will be described as the upper track groove, and track groove 11B as the lower track groove. Furthermore, when referred to only as the first track surface, it refers to at least one of the first upper track surface and the first lower track surface; when referred only as the second track surface, it refers to at least one of the second upper track surface and the second lower track surface.

[0080] exist Figure 5 In the upper track groove 11A, starting from the center of the slider body 2A, there are a first upper track surface 11Aa, a second upper track surface 11Ab, a third upper track surface 11Ac, and a fourth upper track surface 11Ad that intersects with the end face (length end) 2Aa of the slider body 2A. These four track surfaces are formed by covering the entire width direction (approximately half circumference) of the upper track groove 11A. Here, the first upper track surface 11Aa and the second upper track surface 11Ab are referred to as the inner track surfaces, and the third upper track surface 11Ac and the fourth upper track surface 11Ad are referred to as the end track surfaces. In addition, the third upper track surface 11Ac is sometimes referred to as a partially conical track surface, and the fourth upper track surface 11Ad is sometimes referred to as a curved track surface.

[0081] In the upper track groove 11A, with the upper and lower center lines C1 (imaginary lines) of the groove bottom as boundaries, the area above the upper and lower center lines C1 is called the upper groove surface (Japanese: フランク), and the area below the upper and lower center lines C1 is called the lower groove surface. The upper and lower groove surfaces are symmetrical about the upper and lower center lines C1. The upper and lower center lines C1 and the center line O1 of the straight section of the rolling channel 13A are located on the horizontal reference plane HP (…). Figure 2 )Inside.

[0082] also, Figure 5 The dashed lines extending circumferentially schematically show the boundaries between the first upper track surface 11Aa and the second upper track surface 11Ab, as well as the boundaries between the third upper track surface 11Ac and the fourth upper track surface 11Ad. The first upper track surface 11Aa and the second upper track surface 11Ab, and the third upper track surface 11Ac and the fourth upper track surface 11Ad, are connected by a common tangent in the longitudinal cross-section, so the edges are not actually visible. However, they are shown as dashed lines here for ease of understanding of the structure.

[0083] The first upper track surface 11Aa has the same cross-section orthogonal to the length direction. The center line of the cylindrical space formed by the first upper track surface 11Aa and the track groove 10A of the guide rail 1 is set as the center line O1 of the straight section of the rolling channel 13A. In contrast, the second upper track surface 11Ab, the third upper track surface 11Ac, and the fourth upper track surface 11Ad are formed with locally different cross-sections orthogonal to the length direction.

[0084] The second upper orbital plane 11Ab is in Figure 7 In the cross-section (within the horizontal reference plane HP), it has a convex shape that moves away from the center line O1 of the straight portion as it moves towards the end face 2Aa and has a downward settlement d2, but as... Figure 8 In that side view, it does not have a convex shape (equidistant from the center line O1 of the straight section). The sinking amount refers to the maximum separation distance of each track surface relative to the first upper track surface 11Aa in the cross section passing through the center line O1 of the straight section (set as the cross section passing through the upper track groove 11A).

[0085] The third upper orbital plane 11Ac is in Figure 7 In the cross-section (within the horizontal reference plane HP), there is a convex shape with a downward settlement d3, which moves away from the center axis of the end side track surface that is aligned with or parallel to the center line O1 of the straight section as it moves towards the end face 2Aa. Figure 8 In that side-view observation state, it has a convex shape with a downward sinking amount d3', which moves away from the center axis of the end side track surface that is consistent with or parallel to the center line O1 of the straight section as it moves toward the end face 2Aa. In the cross-section through the center axis of the end side track surface, the surface of the third upper track surface 11Ac is straight, and its tilt angle (the tilt angle relative to the center axis of the end side track surface) is set as θ.

[0086] The fourth upper orbital plane 11Ad is in Figure 7 In the cross-section (within the horizontal reference plane HP), it has a convex shape that moves away from the central axis of the end-side track surface as it moves towards the end face 2Aa and has a downward settlement d4. Additionally, in... Figure 8 In that side-viewed state, it has a convex shape that moves away from the central axis of the end-side track surface as it moves toward the end face 2Aa and has a downward settlement d4'. In the cross-section through the central axis of the end-side track surface, the surface of the fourth upper track surface 11Ad is preferably an outwardly convex arc shape. Here, d2 < d3 < d4, and d3' < d4'.

[0087] exist Figure 7 , Figure 8 In this configuration, the second upper track surface 11Ab begins at a distance L1 from the end face 2Aa of the slider body 2A and ends at a distance L2 from the end face 2Aa. Similarly, the third upper track surface 11Ac begins at a distance L2 from the end face 2Aa of the slider body 2A and ends at a distance L3 from the end face 2Aa. Furthermore, the fourth upper track surface 11Ad begins at a distance L3 from the end face 2Aa of the slider body 2A and ends at the end face 2Aa. Here, it is preferable that L1 > L2 > L3.

[0088] In this embodiment, the surfaces of the third upper track surface 11Ac and the fourth upper track surface 11Ad have a rotationally symmetric shape with a central axis that coincides with or is parallel to the center line O1 of the straight section. Here, the central axis that coincides with or is parallel to the center line O1 of the straight section is referred to as the end-side track surface central axis. The end-side track surface central axis is preferably located within the horizontal reference plane HP. Therefore, the subsidence d3 is approximately equal to the subsidence d3', and the subsidence d4 is approximately equal to the subsidence d4'.

[0089] in addition, Figure 5 The lower track groove 11B shown is parallel to the upper track groove 11A and has the same shape as the upper track groove 11A, so its description is omitted. Moreover, the shapes of the other ends of the upper track groove 11A and the lower track groove 11B are also the same as described above, so their description is omitted.

[0090] (Effects of this implementation method)

[0091] Figure 9 It is to compare the examples with Figure 8 A schematic diagram showing the same side along with the rolling element. Figure 10 This embodiment is related to Figure 8 The same side is shown in the schematic diagram along with the rolling element, but the subsidence of the second upper track surface 11Ab is so small that it is not shown here. Figure 11 This implementation method involves the following: Figure 8 The same schematic diagram is shown along with the rolling element. Here, we will use rolling channel 13A as an example, but the same applies to rolling channel 13B.

[0092] Sometimes, for example, due to the direction conversion path 15 within the end cap 2B (see reference). Figure 3 Due to the influence of centrifugal force, vibration, etc., the rolling element 3 enters the rolling channel 13A from the direction conversion path 15 with its center offset relative to the center line O1 of the straight section of the rolling channel 13A. At this time, the offset of the center of the rolling element 3 from the center line O1 of the straight section of the rolling channel 13A is defined as the eccentricity e. The diameter Da of the rolling element 3 is slightly smaller than the diameter of the rolling channel 13A, so when the eccentricity e is less than half of the diameter difference, the rolling element 3 can smoothly enter the rolling channel 13A. However, when the eccentricity e exceeds half of the diameter difference in the vertical direction, such as... Figure 9 As shown, the rolling element 3 collides and contacts the end edge (edge) of the rolling channel 13A in the entry direction, which may cause noise, damage to the rolling element 3, etc.

[0093] In contrast, according to this embodiment, in Figure 10 The fourth upper track surface 11Ad, with a downward depression d4, is formed at the entry direction end of the rolling channel 13A. Therefore, even when eccentrically positioned with an eccentricity e exceeding half the aforementioned diameter difference, the rolling element 3 entering from the direction-changing path 15 rolls after obliquely contacting the fourth upper track surface 11Ad, which is a convex arc shape, and then rolls on the locally conical third upper track surface 11Ac and the second upper track surface 11Ab, thereby smoothly changing the direction of movement and being guided to the first upper track surface 11Aa. Thus, by suppressing the generation of large contact pressure, noise generation and damage to the rolling element 3 can be suppressed, ensuring smooth movement of the rolling element 3.

[0094] In addition, Figure 11 In the shown side view, when the rolling element 3, which is eccentrically positioned with an eccentricity e exceeding half of the aforementioned diameter difference, enters through the direction-changing path 15, it rolls after obliquely contacting the fourth upper track surface 11Ad, which has a downward sinking amount d4' and is in the shape of an outwardly convex arc. It then rolls on the partially conical third upper track surface 11Ac and the second upper track surface 11Ab, thereby smoothly changing its direction of movement and being guided to the first upper track surface 11Aa. This mitigates the impact force on the slider body 2A, suppresses noise generation, and prevents damage to the rolling element 3.

[0095] The lower track groove 11B has the same structure as the upper track groove 11A, and therefore achieves the same effect.

[0096] (Machining methods for the first and second upper rail surfaces)

[0097] Next, the processing method of the upper track groove 11A will be explained. Figure 12 This is a schematic diagram showing a portion of the blank and cutting tool TL1 of the slider body 2A as viewed from the orthogonal direction of length. Figure 13 This is a schematic diagram showing the blank of the slider body 2A and the grinding tool TL2 as viewed from the length direction.

[0098] exist Figure 12 , Figure 13 In this design, the length direction of the slider body 2A is defined as the Y direction, the width direction of the slider body 2A is defined as the X direction, and the vertical direction is defined as the Z direction. The Y direction is parallel to the center line O1 of the straight section.

[0099] Figure 12 The cutting tool (second tool) TL1 shown is an end mill or similar device, with a tapered machining edge TL1a on its outer periphery. When the cutting tool TL1 is rotated about its centerline RO1, the rotation trajectory of the machining edge TL1a is consistent with the final surface shape of the third upper guide surface 11Ac and the fourth upper guide surface 11Ad.

[0100] When machining the third upper track surface 11Ac and the fourth upper track surface 11Ad, firstly, a groove similar to the first upper track surface 11Aa is formed in the blank of the slider body 2A by machining. Then, the centerline RO1 of the cutting tool TL1 is kept parallel to the centerline O1 of the straight section. After positioning the blank relative to the slider body 2A in the Y direction, the cutting tool TL1 is rotated around the centerline RO1 and moved parallel to a predetermined position in the X direction (the centerline RO1 is aligned with the rotational axis of the rotational symmetry shape that forms the final surface shape of the third upper track surface 11Ac and the fourth upper track surface 11Ad, i.e., the center axis of the end-side track surface). Thus, the third upper track surface 11Ac and the fourth upper track surface 11Ad can be machined simultaneously in a short time using the formed cutting tool TL1.

[0101] It should be noted that if the inclination angle θ of the third upper track surface 11Ac relative to the central axis of the end side track surface is too large, the amount of raw material removed from the blank in one pass becomes excessive, increasing the resistance during processing and making processing difficult. Therefore, for ease of processing, the inclination angle θ is preferably greater than 0° and less than 45°. From the viewpoint of the effect of the upper track groove 11A, the appropriate range of the inclination angle θ will be described later.

[0102] In the rotation trajectory of the machining blade TL1a, the part corresponding to the third upper track surface 11Ac and the part corresponding to the fourth upper track surface 11Ad are smoothly connected. Therefore, in the longitudinal section of the slider body 2A (the section through the central axis of the end side track surface), the tangent of the third upper track surface 11Ac and the tangent of the fourth upper track surface 11Ad at the boundary of the third upper track surface 11Ac and the fourth upper track surface 11Ad overlap each other.

[0103] Figure 13 The grinding tool (first tool) TL2 shown consists of a belt-shaped grinding stone TL2a and a cylindrical portion TL2b that holds the grinding stone TL2a. When the grinding tool TL2 is cut by a plane passing through the center line RO2 of the grinding tool TL2, the grinding stone TL2a has an outer peripheral surface with the same semi-circular shape as the upper track groove 11A.

[0104] When grinding the first upper track surface 11Aa and the second upper track surface 11Ab, with the center line RO2 of the grinding tool TL2 aligned with the Z direction, the grinding tool TL2, rotating around the center line RO2, abuts against the inner side of the leg 6. After grinding the inner surface of the first upper track surface 11Aa with the outer peripheral surface of the grinding stone TL2a, the grinding tool TL2 is moved toward the end face 2Aa along the Y direction. As a result, the first upper track surface 11Aa is formed linearly along the Y direction.

[0105] The convex surface formed on the second upper track surface 11Ab can be created by controlling the cutting depth of the grinding tool TL2. That is, the convex surface formed on the second upper track surface 11Ab... Figure 7 Changes in subsidence during cross-sectional observation, but in the case of Figure 8 When viewed from the side, there is no convex surface showing any amount of sinking.

[0106] Specifically, after forming the first upper track surface 11Aa, with the center line RO2 aligned with the Z direction, the grinding tool TL2 rotates while moving parallel to the Y direction, and simultaneously moves parallel to the X direction outward as it approaches the end face 2Aa of the slider body 2A. Thus, a surface is formed on... Figure 7 The cross-section, i.e., the slider width direction, has a convex shape, but... Figure 8 The second upper track surface 11Ab, which is the side surface of the slider, does not have a convex shape in the vertical direction. Furthermore, for example, to simplify the machining process, a convex surface may not be provided on the second upper track surface 11Ab. In this case, the grinding tool TL2 is not moved in the X direction. In this case, the internal track surface is only the first upper track surface 11Aa, or the third upper track surface 11Ac is directly connected to the first upper track surface 11Aa. Therefore, when the second upper track surface 11Ab is absent and the third upper track surface 11Ac is directly connected to the first upper track surface 11Aa, the second upper track surface 11Ab will be referred to as the first upper track surface 11Aa below.

[0107] According to this embodiment, the boundaries of the second upper track surface 11Ab and the third upper track surface 11Ac do not substantially share tangents to each other. In other words, in at least one cross-section passing through the center line O1 of the straight section, the tangent of the second upper track surface 11Ab at the boundary of the second upper track surface 11Ab and the tangent of the third upper track surface 11Ac are different. That is, it is permissible for an edge to form at the boundary of the second upper track surface 11Ab and the third upper track surface 11Ac. Therefore, it is possible to form the first upper track surface 11Aa or the second upper track surface 11Ab in a different process than the third upper track surface 11Ac (and the fourth upper track surface 11Ad). The order of machining of the cutting tool TL1 and the grinding tool TL2 is not limited; either can be performed first.

[0108] Thus, according to this embodiment, in the longitudinal cross-section of the slider body 2A (the cross-section through the center line O1 of the straight section), the boundaries of the second upper track surface 11Ab and the third upper track surface 11Ac do not actually need to share a common tangent. Therefore, after machining the third upper track surface 11Ac, it is not necessary to perform finishing on the connecting portion that connects to the second upper track surface 11Ab. As a result, the manufacture of the slider body 2A becomes easier.

[0109] Furthermore, the statement that the second upper orbital surface 11Ab and the third upper orbital surface 11Ac "substantially do not share tangents" means that the boundary between the second upper orbital surface 11Ab and the third upper orbital surface 11Ac lies on an edge line, and they do not share tangents for most of their length. That is, after the formation of the third upper orbital surface 11Ac, when forming the first upper orbital surface 11Aa or the second upper orbital surface 11Ab, it is possible that some tangents may be shared between them locally, but this situation is also included in the structure that "substantially does not share tangents between them".

[0110] (Regarding the tilt angle θ)

[0111] Figure 14 It is shown together with the rolling element. Figure 7 An enlarged schematic diagram of the same cross-section shows an example with a small eccentricity of the rolling element. When the rolling element 3 enters the track surface, with a small eccentricity e, the rolling element 3 first collides with the third upper track surface 11Ac at point P1. Through this collision, a collision force F1 acts between the rolling element 3 and the third upper track surface 11Ac at point P1, and a contact pressure is generated at point P1. The greater the contact pressure, the higher the possibility of damage to the colliding part.

[0112] Regarding the change in the tilt angle θ of the third upper track surface 11Ac, the results of numerical calculations (based on elastic contact theory) of the contact pressure generated by the collision are as follows: Figure 15As shown in the figure. In this calculation, the diameter of the ball is 4.7625mm, the material of the ball and the slider is steel, and the ball velocity V (the component parallel to the linear motion direction) at the time of collision is 1m / s.

[0113] Figure 15 The horizontal axis represents the tilt angle θ (deg). Figure 15 The vertical axis represents the ratio of contact pressures at various tilt angles, with the contact pressure at a tilt angle θ = 30° as the baseline (ratio = 1). According to... Figure 15 The results show that if the tilt angle θ is set to less than 10°, the reduction effect on contact pressure becomes significant. That is, the tilt angle θ of the third upper track surface 11Ac is preferably less than 10°.

[0114] (Regarding the radius of curvature r)

[0115] Figure 16 It will be with Figure 7 An enlarged schematic diagram showing the same cross-section and rolling elements illustrates an example with a large eccentricity of the rolling elements. When the rolling element 3 enters the track surface, with a large eccentricity e, the rolling element 3 collides with the fourth upper track surface 11Ad at point P2. Through this collision, a collision force F2 acts between the rolling element 3 and the fourth upper track surface 11Ad at point P2, and simultaneously, a contact pressure is generated at point P2. Figure 16 The radius of curvature of the cross section of the fourth upper track surface 11Ad is set as r, and the diameter of the rolling element 3 is set as Da.

[0116] Regarding the case where the radius of curvature r of the profile of the fourth upper track surface 11Ad has been changed, the results of numerical calculations (based on elastic contact theory) of the contact pressure based on the collision are as follows: Figure 17 As shown. Calculation conditions and Figure 15 same.

[0117] Figure 17 The horizontal axis represents the ratio of the radius of curvature r to the diameter Da of the rolling element (r / Da). Figure 17 The vertical axis represents the ratio of contact pressures at various arc radii when the contact pressure is r / Da = 0.06 (r = 0.3 mm) as a reference (ratio = 1). Based on... Figure 17 The results show that if the ratio of the radius of curvature r to the rolling element diameter Da is 0.2 or more, the reduction in contact pressure becomes significant. That is, the radius of curvature r of the fourth upper track surface 11Ad is preferably 0.2 times or more the rolling element diameter Da.

[0118] (Regarding the amount of subsidence)

[0119] Figure 18 This is an enlarged view of the end of Embodiment 1, which is equivalent to this embodiment. Figure 7 The same sectional view, Figure 19 The end of Comparative Example 1 is shown magnified. Figure 7 The same sectional view, Figure 20 The end of Comparative Example 2 is shown magnified. Figure 7 The same sectional view, Figure 21 The end of Comparative Example 3 is shown magnified. Figure 7 Same sectional view.

[0120] (Example 1)

[0121] In this embodiment, such as Figure 18 As shown, it has a third upper track surface 11Ac with a straight cross section and a fourth upper track surface 11Ad with an arc cross section. The fourth upper track surface 11Ad has a convex shape with a sinkage amount d4.

[0122] Here, in the case of eccentricity during the entry of the rolling element, a sufficient amount of subsidence d4 is required to guide the rolling element smoothly. Simultaneously, to avoid damage to the third upper track surface 11Ac, as mentioned above, the tilt angle θ of the third upper track surface 11Ac needs to be reduced. Here, as an example, the tilt angle θ = 10°, the subsidence d4 = 0.4 mm, and the longitudinal length L2 of the third upper track surface 11Ac and the fourth upper track surface 11Ad = 1.5 mm.

[0123] (Comparative Example 1)

[0124] In contrast, Figure 19 In Comparative Example 1 shown, there is a structure that has only a third upper track surface 11Ac as an end side track surface and does not have a fourth upper track surface 11Ad. Therefore, the third upper track surface 11Ac intersects with the end surface 2Aa.

[0125] According to Comparative Example 1, when the tilt angle θ of the third upper track surface 11Ac is reduced while ensuring a sufficiently large sinking amount d4, the length L2 of the third upper track surface 11Ac in the longitudinal direction becomes longer. Specifically, if the tilt angle θ of the third upper track surface 11Ac is ensured to be 10° and the sinking amount d4 to be 0.4 mm, the length L2 of the third upper track surface 11Ac in the longitudinal direction is 2.4 mm, which is longer than that in Example 1.

[0126] When using a linear motion guide device, the slider 2 bears the load, which is supported by the guide rail 1 via the rolling element 3. At this time, only the inner side of the slider's track surface bears the load. That is, if the end side track surface becomes longer, the length of the load-bearing inner side track surface becomes shorter, which may reduce the lifespan of the linear motion guide device.

[0127] (Comparative Example 2)

[0128] exist Figure 20 Comparative Example 2, as shown, has the same structure as Comparative Example 1, but the length L2 of the third upper track surface 11Ac in the longitudinal direction is set to 1.5 mm, the same as in Example 1. With this structure, the length of the load-bearing inner track surface can be ensured to be the same as in Example 1.

[0129] However, if the tilt angle θ of the third upper track surface 11Ac is set to 10°, as in Example 1, the subsidence d4 of Comparative Example 2 is 0.25 mm, which is smaller than the subsidence d4 of Example 1, which is 0.4 mm. That is, the allowable eccentricity e of the rolling element is smaller, making it difficult to ensure smooth entry of the rolling element.

[0130] In contrast, according to Embodiment 1 corresponding to this embodiment, the end side track surface is formed by the third upper track surface 11Ac with a straight cross section and the fourth upper track surface 11Ad with a circular arc cross section. Therefore, the tilt angle θ can be suppressed to a small extent, maintaining the durability against the impact of the rolling element, and ensuring sufficient sinking to maintain the smooth movement of the slider.

[0131] (Comparative Example 3)

[0132] On the other hand, Figure 21 In Comparative Example 3 shown, similar to Example 1, the end side track surface is formed by the third upper track surface 11Ac and the fourth upper track surface 11Ad, but both the third upper track surface 11Ac and the fourth upper track surface 11Ad have a straight cross-section.

[0133] In Comparative Example 3, similar to Example 1, the tilt angle θ of the third upper track surface 11Ac is 10°, the sinking amount d4 of the fourth upper track surface 11Ad is 0.4mm, and the length L2 of the third upper track surface 11Ac and the fourth upper track surface 11Ad in the longitudinal direction is 1.5mm.

[0134] In Comparative Example 3, the cross-sections of the third upper track surface 11Ac and the fourth upper track surface 11Ad are straight, therefore, a circumferentially extending edge must be generated at their boundary (point P3). That is, the third upper track surface 11Ac and the fourth upper track surface 11Ad do not share a tangent. The boundary between the third upper track surface 11Ac and the fourth upper track surface 11Ad becomes an edge, therefore, when the rolling element 3 collides with the edge, a very large contact pressure is generated (in... Figure 17 (This is equivalent to a situation where r / Da is very small). Therefore, there are concerns about durability at high speeds.

[0135] In contrast, in Embodiment 1 corresponding to this embodiment, in a cross-section including the central axis of the end-side track surface, the third upper track surface 11Ac and the fourth upper track surface 11Ad of the end-side track surface are smoothly connected with a shared tangent. This prevents the formation of ridges (edges) at the boundary between the third upper track surface 11Ac and the fourth upper track surface 11Ad, and even if the rolling element 3 collides with the boundary, excessive contact pressure will not be generated, eliminating concerns about reduced durability.

[0136] (Second Implementation)

[0137] Figure 22 The slider body 2A of the second embodiment is with Figure 8 The same side view is shown. The shape of the upper track groove 11A in this embodiment is the same as in the first embodiment, but the surface roughness of the third upper track surface 11Ac and the fourth upper track surface 11Ad is coarser than the surface roughness of the first upper track surface 11Aa. The surface roughness of the second upper track surface 11Ab is approximately equal to the surface roughness of the first upper track surface 11Aa. Surface roughness can be evaluated by the arithmetic mean roughness Ra, for example, the arithmetic mean roughness Ra of the third upper track surface 11Ac and the fourth upper track surface 11Ad is preferably 50% or more coarser than the arithmetic mean roughness Ra of the first upper track surface 11Aa. The same applies to the lower track groove 11B. Other than this, the structure is the same as in the first embodiment, therefore, repeated descriptions are omitted.

[0138] When the rolling element enters the track surface, the initial impact is on the third upper track surface 11Ac or the fourth upper track surface 11Ad. If the third upper track surface 11Ac or the fourth upper track surface 11Ad absorbs and sufficiently dampens the impact of the rolling element, subsequent impacts caused by bouncing can be mitigated, and improvements in the durability of the linear motion guide device can be expected. To achieve such damping, increasing the roughness of the third upper track surface 11Ac or the fourth upper track surface 11Ad to facilitate the retention of lubricants such as grease is effective.

[0139] In this embodiment, concentric circular irregularities are provided on the third upper track surface 11Ac and the fourth upper track surface 11Ad to increase the surface roughness. This roughness can be achieved by providing irregularities on the machining edge TL1a of the cutting tool TL1 that processes the third upper track surface 11Ac and the fourth upper track surface 11Ad. For example, the height between the ridges and valleys is approximately 5 μm to 10 μm, and the distance between adjacent ridges is approximately 0.2 mm. Alternatively, a spiral irregularity can be formed by moving the cutting tool TL1 synchronously with its rotation along the Y direction.

[0140] This invention is not limited to the embodiments described above. Combining the various structures of the embodiments with each other, making changes or applications based on the description in the specification and well-known technologies by those skilled in the art are also part of this invention and are included within the scope of protection.

[0141] Various embodiments have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. It will be apparent to those skilled in the art that various modifications or alterations will occur within the scope of the claims, and these modifications or alterations are also within the technical scope of the present invention. Furthermore, the constituent elements of the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0142] Furthermore, this application is based on Japanese Patent Application No. 2024-007502, filed on January 22, 2024, the contents of which are incorporated herein by reference.

[0143] Explanation of reference numerals in the attached figures

[0144] 1 guide rail

[0145] 2 sliders

[0146] 2A Slider Body

[0147] 2B end cap

[0148] 3. Rolling element

[0149] 4. Holder

[0150] 10A and 10B track slots

[0151] 11A, 11A track slot

[0152] 13A and 13B Scrolling Channels

[0153] 14A, 14B Return Channel

[0154] 15 Directional Change Route

Claims

1. A linear motion guiding device, characterized in that, have: guide; A slider, the slider being configured to move relative to a guide rail in the length direction; and A plurality of rolling elements, wherein the plurality of rolling elements are configured to roll freely along a rolling channel formed between the guide rail and the slider, wherein... The slider has: A slider body, the slider body having a track surface that is disposed opposite to the track groove of the guide rail and forms a rolling channel for the rolling element, and a return channel for the rolling element; and End cap, the end cap having a direction conversion path connecting the return channel and the rolling channel, The track surface has: an end-side track surface that intersects the longitudinal end face of the slider body; and an inner-side track surface that is disposed on the opposite side of the longitudinal end face, separated from the end-side track surface. The end-side track surface is a rotationally symmetric shape with reference to a central axis of the end-side track surface that is aligned with or parallel to the center line of the straight section of the rolling channel, and has: a partially conical track surface connected to the inner side track surface; and a curved track surface connecting the partially conical track surface to the longitudinal end face. In a cross-section including the central axis of the end-side track surface, the surface of the partially conical track surface is straight, and the surface of the curved track surface is arc-shaped. In the cross-section, the tangents of the partial conical track surface and the curved track surface at the boundary between the partial conical track surface and the curved track surface are common.

2. The linear motion guiding device according to claim 1, characterized in that, The inner side track surface has a first track surface and a second track surface connecting the first track surface to the partial conical track surface. In the cross-section of the rolling channel including the centerline of the straight section, the second track surface moves away from the centerline of the straight section as it approaches the partial conical track surface.

3. The linear motion guiding device according to claim 1, characterized in that, In at least one of the cross sections of the rolling channel that includes the center line of the straight section, the tangent of the inner side track surface at the boundary between the inner side track surface and the end side track surface is different from the tangent of the end side track surface.

4. The linear motion guiding device according to claim 1, characterized in that, The inclination angle θ of the partial conical track surface relative to the central axis of the end side track surface is less than 10°.

5. The linear motion guiding device according to claim 1, characterized in that, In a cross-section including the central axis of the end-side track surface, the radius of curvature (r) of the curved track surface is more than 0.2 times the diameter (Da) of the rolling element.

6. The linear motion guiding device according to claim 1, characterized in that, The surface roughness of the end side track surface is greater than that of the inner side track surface.

7. A method for manufacturing a linear motion guiding device, characterized in that, The linear motion guiding device has: guide; A slider, the slider being configured to move relative to a guide rail in the length direction; and A plurality of rolling elements are configured to roll freely within a rolling channel formed between the guide rail and the slider. The slider has: The slider body has a track surface that is configured opposite to the track groove of the guide rail and forms a rolling channel for the rolling element, and a return channel for the rolling element; as well as End cap, the end cap having a direction conversion path connecting the return channel and the rolling channel, The track surface has: an end-side track surface that intersects the longitudinal end face of the slider body; and an inner-side track surface that is disposed on the opposite side of the longitudinal end face, separated from the end-side track surface. The end-side track surface is a rotationally symmetric shape with reference to a central axis of the end-side track surface that is aligned with or parallel to the center line of the straight section of the rolling channel, and has: a partially conical track surface connected to the inner side track surface; and a curved track surface connecting the partially conical track surface to the longitudinal end face. In the manufacturing method of the linear motion guide device: When the width direction of the slider body is defined as the X direction, the length direction of the slider body is defined as the Y direction, and the direction orthogonal to the X and Y directions is defined as the Z direction, The first tool rotates about a rotation axis parallel to the Z direction while moving parallel to the slider body along the Y direction, thereby forming the inner side track surface. The second tool rotates about a rotation axis parallel to the center line of the straight section of the rolling channel while moving parallel to the slider body in the X direction, thereby forming the end side track surface. In a cross-section including the central axis of the end-side track surface, the surface of the partially conical track surface is formed as a straight line, and the surface of the curved track surface is formed as an arc. In the cross-section, the tangents of the partial conical track surface and the curved track surface at the boundary between the partial conical track surface and the curved track surface are common.

8. The method for manufacturing the linear motion guiding device according to claim 7, characterized in that, The first tool moves along the Y direction while simultaneously moving along the X direction.

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