Motion guidance device
The motion guide device addresses the issue of premature circulation groove deterioration by sealing the reverse movement area of rolling elements, improving durability and operation efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- THK CO LTD
- Filing Date
- 2022-09-21
- Publication Date
- 2026-07-01
AI Technical Summary
The existing motion guiding devices suffer from premature deterioration of circulation grooves due to the reverse movement of rolling elements, which leads to reduced durability.
A motion guide device with a raceway member, a block containing circulation, return, and turn grooves, and a cover member that seals the reverse movement area of rolling elements, enhancing durability by preventing reverse movement.
The solution improves the movement of rolling elements and enhances the durability of circulation grooves by sealing the reverse movement area, ensuring smoother operation and extended device life.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a motion guiding device including a track member and a block.
Background Art
[0002] Conventionally, a motion guiding device called a linear guide including a track member and a block has been known. As one type of motion guiding device, the applicant has proposed a motion guiding device in which a circulation groove including a rolling groove, a return groove, and a turn groove is formed in a block (see Patent Document 1). According to this motion guiding device, by forming a circulation groove in the block, the rolling elements can be circulated, and thus the effect that the manufacturing of the block becomes easy is achieved.
[0003] In the motion guiding device described in Patent Document 1, a rolling groove is formed in the track member. A circulation groove including a rolling groove, a return groove, and a turn groove is formed in the block. A plurality of rolling elements are arranged in the circulation groove. When the block is relatively moved with respect to the track member, the rolling elements roll between the rolling groove of the track member and the rolling groove of the block. The rolling elements that have rolled between the rolling groove of the track member and the rolling groove of the block enter the turn groove of the block, move through the turn groove, and then enter the return groove of the block. Thereafter, the rolling elements move in the return groove of the block in a direction opposite to the rolling groove, enter another turn groove, move through another turn groove, and then enter between the rolling groove of the track member and the rolling groove of the block again.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the motion control device described in Patent Document 1, a circulation groove is formed in the block, and the rolling elements are in contact with the track members throughout the entire circulation groove. As mentioned above, the direction of movement of the rolling elements in the return groove is reversed from the direction of movement of the rolling elements in the rolling groove. In the return groove, the rolling elements move in the opposite direction to the track members. This may lead to deterioration of movement or premature deterioration of the circulation groove.
[0006] The reverse movement of rolling elements is explained below. Assuming the block is fixed and the track members move, in the rolling grooves of the block, the rolling elements rotate and move in the same direction as the track members. On the other hand, in the return grooves of the block, the rolling elements are pushed by the following rolling elements and move in the opposite direction to the direction of travel of the track members. Therefore, in the return grooves, the rolling elements move in the opposite direction to the track members. In reality, the track members are often fixed and the blocks move. Even in this case, if we consider the movement of the blocks relative to the track members to be relative, we can think of it in the same way.
[0007] The present invention has been made in view of the above problems, and aims to provide a motion guide device that can improve the movement of rolling elements and enhance the durability of the circulation grooves of the blocks. [Means for solving the problem]
[0008] To solve the above problems, one aspect of the present invention is a motion guide device comprising a raceway member having a rolling groove, a block having a circulation groove including a rolling groove, a return groove, and a turn groove facing the rolling groove of the raceway member, and a plurality of rolling elements arranged in the circulation groove, wherein the rolling elements are scooped up while being sandwiched between the turn groove of the block and the rolling groove of the raceway member, and a cover member that closes a part of the turn groove and the return groove is attached to the block. [Effects of the Invention]
[0009] According to one aspect of the present invention, the area where the rolling elements were moving in reverse is sealed by the cover member while leaving the parts necessary for circulation, such as the starting point of the rolling elements' scooping, thereby improving the movement of the rolling elements and enhancing the durability of the circulation grooves in the block. [Brief explanation of the drawing]
[0010] [Figure 1] This is a perspective view of a motion guidance device according to one embodiment of the present invention. [Figure 2] This is a front view of the motion guidance device of this embodiment. [Figure 3] Figure 3(a) is a plan view of the motion guide device of this embodiment, and Figure 3(b) is a side view. [Figure 4] This is an exploded perspective view of the block of this embodiment. [Figure 5] This is a perspective view of the lid member of this embodiment. [Figure 6] This figure shows the change in the cross-sectional shape of the turn groove of the block in this embodiment. [Figure 7] This is a schematic diagram of the circulation groove of the block in this embodiment. [Modes for carrying out the invention]
[0011] Hereinafter, the motion guidance device of an embodiment of the present invention will be described in detail with reference to the attached drawings. However, the motion guidance device of the present invention can be embodied in various forms and is not limited to the embodiments described in this specification. This embodiment is provided with the intention that those skilled in the art will be able to fully understand the invention by making full disclosures in this specification.
[0012] Figure 1 shows a perspective view of a motion guidance device 1 according to one embodiment of the present invention. Figure 2 shows a front view of the motion guidance device 1 according to this embodiment.
[0013] As shown in Figure 1, the motion guide device 1 of this embodiment is a linear guide comprising a track member 2 and a block 4. The track member 2 is a rail. The block 4 is assembled to the track member 2 so as to be able to move relative to it in the longitudinal direction. A circulation groove 5 is formed in the block 4. Multiple rolling elements 3, such as balls and rollers, are arranged in the circulation groove 5.
[0014] For the sake of convenience in the following description, the configuration of the motion guiding device 1 will be described using the directions when the track member 2 attached to the horizontal plane is viewed from the longitudinal direction, that is, the up-down, left-right, and front-back directions in FIG. 1. Of course, the arrangement of the motion guiding device 1 is not limited to this, and the track member 2 may be attached to a vertical plane, or the motion guiding device 1 may be turned upside down.
[0015] The track member 2 has an upper surface 2a, a pair of left and right side surfaces 2b, and a bottom surface 2c. On the side surface 2b of the track member 2, a rolling groove 7 is formed along the longitudinal direction. The rolling groove 7 extends linearly. The number of the rolling grooves 7 is two, four, or the like. On the upper surface 2a of the track member 2, a plurality of mounting holes 6 for mounting the track member 2 on a base are formed.
[0016] As shown in FIG. 2, the rolling groove 7 is a groove that opens toward the block 4, and its depth is shallower than the radius of the rolling element 3. The cross-sectional shape of the rolling groove 7 is a Gothic arch shape. The cross-sectional shape of the rolling groove 7 may also be a circular arc shape. On the side surface of the track member 2 above the rolling groove 7, a convex portion 13 that protrudes laterally more than the lower side surface 12 is formed. The convex portion 13 is continuous with the rolling groove 7 and is convex arc-shaped toward the side.
[0017] The block 4 has a substantially U-shaped cross-section and is arranged so as to straddle the track member 2. The block 4 has a web portion 4a facing the upper surface 2a of the track member 2 and a pair of left and right sleeve portions 4b facing the side surface 2b of the track member 2.
[0018] As shown in FIG. 1, a circulation groove 5 including a rolling groove 8, a return groove 9, and a turn groove 10 is formed in the block 4. The block 4 is a single structure. The block 4 may be divided into a central portion where the rolling groove 8 and the return groove 9 are formed and an end portion where the turn groove 10 is formed.
[0019] Fig. 3(a) shows a plan view of the motion guide device 1 of the present embodiment, and Fig. 3(b) shows a side view. A rolling groove 8 facing the rolling groove 7 of the track member 2 is formed in the sleeve portion 4b of the block 4. The rolling groove 8 extends linearly. A return groove 9 is formed in the web portion 4a of the block 4. The return groove 9 is parallel to the rolling groove 8 and extends linearly. A turn groove 10 is connected to the rolling groove 8 and the return groove 9. The turn groove 10 serves to reverse the traveling direction of the rolling element 3. In both the plan view shown in Fig. 3(a) and the side view shown in Fig. 3(b), the turn groove 10 is bent, and the turn groove 10 is three-dimensionally bent. The dashed-dotted line in Figs. 3(a) and 3(b) indicates the track of the rolling element 3. The turn apex P of the turn groove 10 is where the rolling element 3 is positioned at the outermost end in the front-rear direction. The rolling element 3 reverses its traveling direction in the front-rear direction with the turn apex P as the boundary.
[0020] As shown in Fig. 2, in the longitudinal view of the track member 2, the turn groove 10 is, for example, in a J shape combining an arc and a straight line. The turn groove 10 may be in a single arc shape.
[0021] Fig. 4 shows an exploded perspective view of the block 4. As described above, the rolling groove 8 is formed in the sleeve portion 4b of the block 4. The rolling groove 8 is a groove that opens toward the track member 2, and its depth is shallower than the radius of the rolling element 3. The cross-sectional shape of the rolling groove 8 is a Gothic arch shape. The cross-sectional shape of the rolling groove 8 may also be a circular arc shape. [[ID=???]]
[0022] <\\ As described above, the return groove 9 is formed in the web portion 4a of the block 4. The return groove 9 is a groove that opens toward the track member 2, and its depth is deeper than the diameter of the rolling groove 8. The turn groove 10 is formed at the corner of the sleeve portion 4b and the web portion 4a of the block 4. The turn groove 10 is a groove that opens toward the track member 2, and its depth gradually increases from the rolling groove 8 side toward the return groove 9 side.
[0023] It should be noted that there seems to be an incorrect tag format in the original text for which might be a formatting error in the input. I've translated it as is while preserving the original incorrect format. Also, the "diameter" mentioned for the return groove depth comparison in seems a bit odd as it's not clear what diameter is being referred to in relation to the rolling groove 8. It might be a miswording in the original, but I've translated it based on the given text.A cover member 11 is attached to the lower surface of the web portion 4a of block 4. The cover member 11 closes the return groove 9 and also closes a portion of the turn groove 10. As shown in Figure 2, the cover member 11 is positioned between the lower surface of the web portion 4a of block 4 and the upper surface 2a of the track member 2. A gap g is provided between the cover member 11 and the track member 2, allowing the cover member 11 to move relative to the track member 2.
[0024] As shown in Figure 5, the lid member 11 is plate-shaped. A flat surface 11a is formed in the center of the upper surface of the lid member 11. Curved surfaces 11b are formed at both corners in the width direction of the lid member 11. As shown in Figure 2, the lid member 11 covers at least the area from the end Q on the return groove 9 side of the turn groove 10 to the turn apex P (see also Figure 3(a)). The flat surface 11a of the lid member 11 covers the return groove 9 and also covers the straight portion of the turn groove 10. The curved surface 11b of the lid member 11 covers the arc portion of the turn groove 10.
[0025] As shown in Figure 2, in a longitudinal view of the track member 2, the curved surface 11b of the cover member 11 is arc-shaped. The radius R2 of the arc of the curved surface 11b of the cover member 11 is equal to the radius R1 of the arc of the convex portion 13 of the track member 2. R1 and R2 may be different.
[0026] As shown in Figure 5, the lid member 11 has a constant cross-sectional shape in the longitudinal direction and is a single structure. The lid member 11 has mounting holes 11c formed in it for attaching to the block 4. Positioning pins, bosses, positioning holes, etc. may be provided on the lid member 11 for positioning on the block 4. The lid member 11 may also be divided into two or more parts. The cross-sectional shape of the lid member 11 may be, for example, a rectangle, and a groove with a curved surface may be formed in the part facing the turn groove 10.
[0027] Figure 6 shows the change in the cross-sectional shape of the turn groove 10 of block 4. Figure 6(a) shows the cross-sectional view along line aa in Figure 3(b), indicating the turn start point of the turn groove 10. Figure 6(b) shows the cross-sectional view along line bb in Figure 3(b), Figure 6(c) shows the cross-sectional view along line cc in Figure 3(b), and Figure 6(d) shows the cross-sectional view along line dd in Figure 3(b).
[0028] As shown in Figures 6(a) to (d), the rolling element 3 is scooped up while being sandwiched between the turn groove 10 and the rolling groove 7 of the track member 2. That is, the rolling element 3 that has moved along the rolling groove 8 of block 4 reaches the turn initiation point shown in Figure 6(a). Upon reaching the turn initiation point, the rolling element 3 is scooped up while being sandwiched between the rolling groove 7 of the track member 2 and the turn groove 10 of block 4, as shown in Figures 6(a) and 6(b). In this embodiment, the trajectory of the rolling element 3 is changed to the upper right.
[0029] As shown in Figures 6(b) and 6(c), the rolling element 3 overcomes the rolling groove 7 of the track member 2 while being sandwiched between the rolling groove 7 of the track member 2 and the turning groove 10 of the block 4. As shown in Figure 6(d), having overcome the rolling groove 7 of the track member 2, the rolling element 3 moves upward in Figure 6(d) while being sandwiched between the protrusion 13 of the track member 2 and the turning groove 10 of the block 4.
[0030] As the rolling element 3 moves above the track member 2, the clamping force between the track member 2 and the block 4 is released. The rolling element 3 is pushed by the following rolling element 3 and enters the turn groove 10 which is closed by the cover member 11.
[0031] As shown in Figures 6(a) to (d), the depth of the turn groove 10 gradually increases from the rolling groove 8 side towards the return groove 9 side. At the turn apex P, the depth of the turn groove 10 is greater than or equal to the diameter of the rolling element 3.
[0032] As shown in Figures 6(a) to (d), the turn groove 10 has an undercut portion U that narrows the groove width toward the opening of the turn groove 10. The undercut portion U is a protrusion formed on the wall surface of the turn groove 10.
[0033] Figure 7 shows a schematic diagram of the circulation groove 5 of block 4. 8 is the rolling groove, 9 is the return groove, and 10 is the turn groove. In the rolling groove 8, the rolling element 3 is squeezed and compressed between the rolling groove 7 of the raceway member 2 and the rolling groove 8 of block 4. Therefore, when block 4 is moved relative to the raceway member 2, the rolling element 3 rolls between the rolling groove 7 of the raceway member 2 and the rolling groove 8 of block 4. The rolling element 3 that has moved to one end of the rolling groove 8 of block 4 enters the turn groove 10 of block 4.
[0034] In the turn groove 10, as described above, the rolling element 3 is caught between the rolling groove 7 of the track member 2 and the rolling groove 8 of the block 4, passes over the rolling groove 7 of the track member 2, and enters the turn groove 10 which is closed by the cover member 11. After moving through the turn groove 10, the rolling element 3 is pushed by the following rolling element 3 and enters the return groove 9 of the block 4.
[0035] In the return groove 9, the rolling element 3 moves in the opposite direction to the direction of travel in the rolling groove 8, pushed by the following rolling element 3. After moving through the return groove 9, the rolling element 3 enters another turn groove 10, moves through the other turn groove 10, and then enters again between the rolling groove 7 of the track member 2 and the rolling groove 8 of the block 4.
[0036] The shaded area in Figure 7 indicates the range in which the cover member 11 blocks the circulation groove 5. The cover member 11 blocks the return groove 9 and at least the range from the end Q on the return groove 9 side of the turn groove 10 to the turn apex P. This range is the range in which the rolling elements 3 move in reverse. By blocking the range in which the rolling elements 3 move in reverse with the cover member 11, the movement of the rolling elements 3 can be improved, and the durability of the circulation groove 5 of the block 4 can be improved.
[0037] On the other hand, the cover member 11 does not block the starting point of the rolling element 3's scooping (near the end R of the turn groove 10 on the rolling groove 8 side). This is because, at the starting point of the rolling element 3's scooping, the direction of travel of the rolling element 3 and the relative direction of movement of the track member 2 coincide, and the circulation of the rolling element 3 is assisted by the track member 2.
[0038] The configuration and effects of the motion guidance device 1 of this embodiment have been described above. The motion guidance device 1 of this embodiment further provides the following effects.
[0039] Since the lid member 11 has a curved surface 11b that covers a portion of the turn groove 10, the three-dimensionally curved turn groove 10 can be covered by the lid member 11.
[0040] An undercut portion U is formed in the turn groove 10, narrowing the groove width toward the opening of the turn groove 10. This reduces the play of the rolling element 3 toward the inner circumference of the turn groove 10, allowing the rolling element 3 to move smoothly through the turn groove 10. In more detail, as shown in Figure 2, a gap g exists between the cover member 11 and the raceway member 2 on the inner circumference of the turn groove 10. By forming an undercut portion U in the turn groove 10, the amount of play of the rolling element 3 toward the inner circumference of the turn groove 10 is reduced, and the rolling element 3 is pressed toward the outer circumference of the turn groove 10 by centrifugal force. Therefore, it is possible to suppress the movement of the rolling element 3 along the gap g on the inner circumference of the turn groove 10.
[0041] Since the cover member 11 is attached to the lower surface of the web portion 4a of block 4, the area in which the rolling element 3 moves in the reverse direction can be effectively blocked.
[0042] Since the lid member 11 is plate-shaped, it is easy to manufacture.
[0043] Furthermore, the present invention is not limited to being embodied in the above embodiments, and can be embodied in other embodiments without changing the gist of the invention.
[0044] In the above embodiment, an example of a total rolling element was described, but spacers may be interposed between the rolling elements.
[0045] In the above embodiment, an example of an outer block type linear guide in which a block with a substantially U-shaped cross-section straddles a track member was described, but an inner block type linear guide in which an inner block is arranged inside an outer rail with a substantially U-shaped cross-section may also be used.
[0046] In the above embodiment, an example of a linear guide was described for the motion guide device, but the motion guide device may also be a ball spline. [Explanation of symbols]
[0047] 1…Motion guide device, 2…Track member, 3…Rolling element, 4…Block, 4a…Web section, 4b…Sleeve section, 5…Circulation groove, 7…Rolling groove of track member, 8…Rolling groove of block, 9…Return groove, 10…Turn groove, 11…Cover member, 11b…Curved surface of cover member, P…Turn apex, Q…End of turn groove on the return groove side, R…End of turn groove on the rolling groove side, U…Undercut section
Claims
1. A track member having rolling grooves, A block having a circulating groove including rolling grooves, return grooves, and turn grooves that are opposite to the rolling grooves of the aforementioned track member, The system comprises a plurality of rolling elements arranged in the circulation groove, All of the rolling grooves, return grooves, and turn grooves of the block are grooves that open toward the raceway member. The rolling element is scooped up while being sandwiched between the turn groove of the block and the rolling groove of the raceway member, The block is a motion guide device to which a cover member is attached that closes a part of the turn groove and the return groove.
2. The motion guide device according to claim 1, characterized in that the cover member covers at least the range from the end of the turn groove on the return groove side to the turn apex.
3. The motion guide device according to claim 1 or 2, characterized in that the cover member has a curved surface that curves in a longitudinal view of the track member and covers a part of the turn groove.
4. The motion guide device according to claim 1 or 2, characterized in that the turn groove has an undercut portion that narrows the groove width toward the opening of the turn groove.
5. The block has a web portion facing the upper surface of the track member and in which the return groove is formed, and a sleeve portion facing the side surface of the track member and in which the rolling groove is formed, The motion guide device according to claim 1 or 2, characterized in that the cover member is attached to the lower surface of the web portion.
6. The motion guide device according to claim 5, characterized in that the cover member is plate-shaped.