Motion guiding device

Abstract

Provided is a motion guide device capable of improving performance such as repeated durability and operation of a turning section. The motion guide device sandwiches the balls (3) between the wall surface of the rolling groove (7) of the track member (2) and the wall surface of the turning groove (10) of the block (4), and changes the track of the balls (3) that have moved in the rolling path. When the track member side clamping angle is set to be alpha and the block side clamping angle is set to be beta, alpha + beta < 180 degrees is satisfied.

Description

Technical Field

[0001] The present invention relates to a motion guide device for guiding the linear motion or curved motion of a movable body such as a workbench. Background Art

[0002] A motion guide device for guiding the linear motion or curved motion of a movable body such as a workbench is known (see Patent Document 1). The motion guide device includes a track member and a block that can move relative to the track member. A plurality of balls are sandwiched between the track member and the block so as to enable rolling motion.

[0003] The track member has a rolling groove extending in the longitudinal direction. The block has a rolling groove facing the rolling groove of the track member, and has a return portion and a turning portion.

[0004] The circulation path is composed of a rolling path between the rolling groove of the track member and the rolling groove of the block, a return portion, and a turning portion. A plurality of balls are arranged in the circulation path. When the block is moved relative to the track member, the balls move in the rolling path. The balls that have moved in the rolling path are guided to the turning portion, then move in the opposite direction in the return portion, and then are guided to the rolling path from another turning portion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. WO2008 / 041589 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the conventional motion guide device, there is a problem that the movement of the ball at the turning portion is not good.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a motion guide device capable of improving performance such as the movement of a ball at a turning portion and the repetition durability of the turning portion.

[0011] Solutions to Solve Problems

[0012] In order to solve the above-mentioned problems, a scheme of the present invention comprises: a track component, which has a rolling groove extending in the length direction; a block, which has a rolling groove opposite to the rolling groove of the track component, a return portion, and a turning portion connected to the rolling groove and the return portion; and a plurality of balls, which are arranged in a circulation path, the circulation path including a rolling path between the rolling groove of the track component and the rolling groove of the block, the return portion, and the turning portion, and a wall surface of the turning groove of the track component and a wall surface of at least a part of the turning portion of the block. The ball is clamped between the two surfaces so that the track of the ball after moving in the rolling path changes, and a track member side clamping angle formed by a line connecting an effective end of the rolling groove of the track member and the center of the ball on the rolling groove of the track member and a center line of the rolling groove of the track member is set to α, and a block side clamping angle formed by a line connecting a tangent point of the turning groove of the block and the ball and a line connecting the center of the ball on the rolling groove of the track member and a center line of the rolling groove of the track member is set to β, at this time, α+β<180° is satisfied.

[0013] Effects of the Invention

[0014] According to one embodiment of the present invention, the resultant force of the reaction force from the track member on the ball and the reaction force from the block on the ball can generate a resultant force component in the track direction of the turning groove. The ball moving in the rolling path can be smoothly guided to the turning groove, thereby improving the performance of the ball movement in the turning groove and the repeated durability of the turning groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view of a motion guide device according to one embodiment of the present invention.

[0016] Figure 2 (a) is a top view of the motion guide device of this embodiment, Figure 2 (b) is a side view.

[0017] Figure 3 It is a front view of the motion guide device of this embodiment.

[0018] Figure 4 (a) shows a bottom side perspective view of a block according to this embodiment, Figure 4 (b) is a perspective view of the upper surface side of the block of this embodiment after being turned over.

[0019] Figure 5 This is a schematic diagram showing a method for processing a block according to the present embodiment.

[0020] Figure 6 It is a cross-sectional view showing a change in the cross-sectional shape of the turning groove of the block according to the present embodiment.

[0021] Figure 7 is a diagram for explaining α and β of this embodiment ( Figure 6 (a) is an enlarged view of the main part of the image.

[0022] Figure 8 It is a diagram for explaining α and β of a comparative example.

[0023] Fig. 9 is a diagram for explaining γ and δ of this embodiment ( Figure 6 (b) is an enlarged view of the main part). DETAILED DESCRIPTION

[0024] Hereinafter, the motion guidance device of the embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the motion guidance device of the present invention can be embodied in various ways and is not limited to the embodiment described in the specification. This embodiment is provided for the purpose of enabling those skilled in the art to fully understand the intent of the invention by making the specification fully disclosed.

[0025] Figure 1 A perspective view showing a motion guide device 1 according to an embodiment of the present invention. Figure 2 A side view of the motion guide device 1 according to the present embodiment is shown. Figure 3 The front view of the motion guide device 1 of the present embodiment is shown. The motion guide device 1 of the present embodiment is a linear guide having a track member 2 and a block 4 that can move relative to the track member 2. A plurality of balls 3 are sandwiched between the track member 2 and the block 4 so as to be able to roll. A circulation path 5 is formed in the block 4 so as to circulate the plurality of balls 3.

[0026] It should be noted that, for the sake of convenience in the following description, the direction when the track member 2 installed on the horizontal plane is observed from the length direction, that is, Figure 1 The structure of the motion guide device 1 is described with reference to the up and down, left and right, front and back directions. Of course, the configuration of the motion guide device 1 is not limited thereto, and the track member 2 may be installed on a vertical plane, or the motion guide device 1 may be turned upside down.

[0027] like Figure 1 As shown, the track member 2 is a track extending in a straight line. The track member 2 has an upper surface 2a, a pair of left and right side surfaces 2b, and a bottom surface 2c. A rolling groove 7 extending along the length direction is formed on the side surface 2b of the track member 2. The rolling groove 7 is in the shape of a pointed arch. The rolling groove 7 can also be in the shape of a single circular arc. A plurality of mounting holes 6 for mounting the track member 2 on a base are formed on the upper surface 2a of the track member 2. It should be noted that the track member 2 can also extend in a curved shape. The number of rolling grooves 7 can be appropriately set to 2, 4, etc. In addition, the configuration of the rolling grooves 7 can also be appropriately set.

[0028] like Figure 3 As shown, the block 4 is roughly U-shaped in cross section and is formed in a manner spanning the track member 2. The block 4 has a web portion 4a that is opposite to the upper surface 2a of the track member 2, and a pair of sleeve portions 4b that hang down from both ends of the web portion 4a in the left and right directions and are opposite to the side surfaces 2b of the track member 2. The block 4 of the motion guide device 1 of this embodiment is a single structure. Figure 1 As shown, the block 4 is formed with a rolling groove 8, a return portion 9, and a turn portion 10. The rolling groove 8 faces the rolling groove 7 of the track member 2.

[0029] Figure 4 (a) shows a bottom side perspective view of block 4, Figure 4 (b) shows a perspective view of the upper surface side of the reversed block 4. A rolling groove 8 is formed in the sleeve portion 4b of the block 4. The rolling groove 8 is in a pointed arch shape. The rolling groove 8 may also be in a single arc shape.

[0030] A return portion 9 is formed in the web portion 4a of the block 4 substantially parallel to the rolling groove 8. The return portion 9 is a groove that opens toward the track member 2. Hereinafter, the return portion 9 will be referred to as the return groove 9. A turning portion 10 connecting the block 4, the rolling groove 8 and the return groove 9 is formed from the sleeve portion 4b of the block 4 to the web portion 4a. The turning portion 10 is a groove that opens toward the track member 2. Hereinafter, the turning portion 10 will be referred to as the turning groove 10.

[0031] It should be noted that the return groove 9 can also be a through hole. In addition, the turning groove 10 is at least at the starting point of the turn (refer to Figure 6 (a)) to the turning apex (refer to Figure 6 The interval of (e) is the slot, starting from the turning vertex (refer to Figure 6 The section from (e)) to the return groove 9 may be a through hole.

[0032] like Figure 3 As shown, of a pair of side surfaces 11 and 12 on the outer side of the rolling groove 7 of the track member 2, the upper side surface 11 in contact with the ball 3 protrudes toward the block 4 side more than the lower side surface 12 not in contact with the ball 3. The cross-sectional shape of the upper side surface 11 of the track member 2 is roughly arc-shaped. The turning groove 10 of the block 4 is bent along the upper side surface 11. The turning groove 10 is roughly J-shaped.

[0033] like Figure 5 As shown, the rolling groove 8 of the block 4 (refer to Figure 4), the return groove 9, and the turning groove 10 are continuously formed on the block 4 using a cutting tool 14 such as an end mill. The connecting parts of the rolling groove 8, the turning groove 10, and the return groove 9 are seamless and do not have any seams. The turning groove 10 is formed in an undercut shape toward the opening, and the details will be described later. Therefore, the cutting tool 14 is expected to use a lollipop-type end mill with a roughly spherical head and a neck with a reduced diameter. It should be noted that the cutting tool 14 is not limited to an end mill. In addition, in addition to cutting, the rolling groove 8, the turning groove 10, and the return groove 9 can also be continuously formed on the block 4 by plastic processing such as forging and stamping.

[0034] like Figure 1 as well as Figure 2 As shown, the circulation path 5 is composed of a rolling path between the rolling groove 7 of the track member 2 and the rolling groove 8 of the block 4, a return groove 9, and a turning groove 10. A plurality of balls 3 are arranged in the circulation path 5. When the block 4 is moved relative to the track member 2, the balls 3 roll in the rolling path. The balls 3 moved to one end of the rolling path are guided to the turning groove 10, and after moving in the opposite direction in the return groove 9, are guided from the other turning groove 10 to the other end of the rolling path.

[0035] Figure 6 The change in the cross-sectional shape of the turning groove 10 of the block 4 is shown. Figure 6 (a) shows Figure 2 (b) aa line cross-sectional view, Figure 6 (b) shows Figure 2 (b) bb line cross-sectional view, Figure 6 (c) shows Figure 2 (b) cc line cross-sectional view, Figure 6 (d) shows Figure 2 (b) dd line cross-sectional view, Figure 6 (e) shows Figure 2 (b) ee line cross-sectional view.

[0036] Figure 6 (a) shows the turning start point of the turning groove 10. The ball 3 moves in the rolling path and reaches Figure 6 The ball 3 that reaches the turning starting point is sandwiched between the wall surface of the rolling groove 7 of the track member 2 and the wall surface of the turning groove 10 of the block 4, and Figure 6 (a) to Figure 6 As shown in (b), its orbit changes to the right in the figure.

[0037] Figure 7 Show Figure 6(a) is an enlarged view of the main part. The rolling groove 7 of the track member 2 is in the shape of a pointed arch. That is, the rolling groove 7 has two arcs of radius r that are slightly larger than the radius of the ball 3. The center of the two arcs of radius r is d. The ball 3 contacts the rolling groove 7 at two points. O is the center of the ball 3 located on the rolling groove 7. The contact angle of the ball 3 with respect to the rolling groove 7 is θ. The effective range of the rolling groove 7 is the arc portion with a constant radius r. e is the effective end of the rolling groove 7 (the end of the effective range). The rolling groove center line G is the center line of the rolling groove 7. In the present embodiment, it is a line connecting the intersection point f of the two arcs of radius r and the center O of the ball 3.

[0038] The motion guide device 1 of the present embodiment satisfies the following formula (1).

[0039] α+β<180° (1)

[0040] In formula (1), α is the track member side clamping angle formed by the line H connecting the effective end e of the rolling groove 7 of the track member 2 and the center O of the ball 3 on the rolling groove 7 of the track member 2 and the rolling groove center line G of the track member 2. It should be noted that the ball 3 contacts the rolling groove 7 of the track member 2 at a contact angle θ, but in order to reliably generate the resultant force component B in the track direction of the turning groove 10 (refer to Figure 6 (a)), α uses the angle α formed by the line H connecting the effective end e of the rolling groove 7 of the track member 2 and the center O of the ball 3 on the rolling groove 7 of the track member 2 and the center line G of the rolling groove of the track member 2.

[0041] β is the block-side clamping angle formed by the line I connecting the center O of the ball 3 on the rolling groove 7 of the track component 2 and the tangent point a between the turning groove 10 of the block 4 and the ball 3 and the rolling groove center line G of the track component 2.

[0042] The motion guide device 1 of the present embodiment can smoothly guide the ball 3 to the turning groove 10 by satisfying the formula (1). The reason for this will be described below.

[0043] like Figure 6 As shown in (a), the ball 3 clamped between the wall surface of the rolling groove 7 of the track member 2 and the wall surface of the turning groove 10 of the block 4 is acted with a reaction force indicated by arrow A1 from the track member 2 side, and a reaction force indicated by arrow A2 from the block 4 side. By satisfying equation (1), the resultant force of the two reaction forces generates a resultant force component B in the track direction of the turning groove 10. Under the action of this resultant force component B, the ball 3 moving in the rolling path can be smoothly guided to the turning groove 10.

[0044] Figure 8A comparative example that does not satisfy equation (1) is shown. When α+β≥180°, the resultant force of the reaction force acting on the ball 3 from the track member 2 side and the reaction force acting on the ball 3 from the block 4 side has a resultant force component B´ in the opposite direction to the track direction of the turning groove 10. Therefore, it is difficult to guide the ball 3 to the track direction of the turning groove 10.

[0045] Again Figure 7 As shown, in the motion guide device 1 of the present embodiment, the tangent point a of the turning groove 10 of the block 4 and the ball 3 is arranged on the line J that passes through the center O of the ball 3 and is orthogonal to the rolling groove center line G of the track member 2, or at a position closer to the track member 2 than the line J. Therefore, the cross-sectional shape of the turning groove 10 becomes an undercut shape toward the opening. An undercut portion 15 (convex portion) shown by the cross-sectional line in the figure is formed in the cross-sectional shape of the turning groove 10. In addition, the distance X between the rolling groove center line G and the tangent point a becomes less than the ball radius D / 2.

[0046] By bringing the tangent point a closer to the track member 2 side in this manner, the block-side clamping angle β can be reduced, and thus the resultant force component B in the track direction toward the turning groove 10 can be made larger.

[0047] like Figure 6 As shown in FIG. 1 , the motion guide device 1 of the present embodiment starts at the turning start point of the turning groove 10 of the block 4 (refer to FIG. Figure 6 The shape angle γ of (a)) to the side of the track member becomes 0° (refer to Figure 6 Within the range of (e)), the following formula (2) is satisfied.

[0048] γ+δ<180° (2)

[0049] In formula (2), if Figure 6 (b) and an enlarged view of its main part Fig. 9 As shown, γ is the angle between the line L connecting the profile curve of the cross section of the track member 2 with the tangent point k of the ball 3 and the center O of the ball 3 and the rolling groove center line G of the track member 2. The maximum value of γ is α. δ is the block side clamping angle between the line M connecting the turning groove 10 of the block 4 with the tangent point a of the ball 3 and the center O of the ball 3 and the rolling groove center line G of the track member 2.

[0050] The motion guide device 1 of this embodiment satisfies the formula (2) from the turning start point to when γ becomes 0°, so that the line L can be parallel to the rolling groove center line G from the turning start point to when γ becomes 0° (see Figure 6 Until (e)), a resultant force component B in the track direction of the turning groove 10 acts on the ball 3 .

[0051] In addition, if Figure 6As shown, in the motion guidance device 1 of the present embodiment, from the turning start point of the turning groove 10 of the block 4 (refer to Figure 6 (a)) until γ becomes 0° (refer to Figure 6 (e)), the tangent point a of the turning groove 10 of block 4 and the ball 3 is arranged on the line J that passes through the center O of the ball 3 and is perpendicular to the rolling groove center line G of the track component 2 or at a position closer to the track component 2 than the line J.

[0052] By doing so, the block-side clamping angle δ can be reduced, and therefore the resultant force component B in the track direction of the turning groove 10 can be increased.

[0053] When γ becomes less than 0°, the ball 3 passes over Figure 6 The turning vertex shown in (e) is only constrained by the turning groove 10 of the block 4. The ball 3 is pushed by the subsequent ball 3 and moves in the turning groove 10 and reaches the return groove 9 (refer to Figure 3 ).

[0054] It should be noted that the rolling groove 7 of the track member 2 may also be in a single arc shape. In this case, the rolling groove center line G of the track member 2 is defined by the contact angle line.

[0055] The configuration and operation of the motion guide device 1 according to the present embodiment have been described above. The motion guide device 1 according to the present embodiment has the following effects.

[0056] The block 4 moves in the rolling path through the rolling groove 7 of the track member 2 and the rolling groove 8 of the block 4 and reaches the turning start point of the turning groove 10 (refer to Figure 6 The resultant force component B in the track direction of the turning groove 10 can act on the ball 3 of (a). Therefore, the repetition durability of the turning groove 10 and the performance of the movement of the ball 3 can be improved.

[0057] By arranging the tangent point a of the turning groove 10 and the ball 3 on the line J or at a position closer to the track member 2 than the line J, it is possible to increase the resultant force component B of the turning groove 10 in the track direction.

[0058] A resultant force component B in the track direction of the turning groove 10 can act on the ball 3 within the range from the turning start point of the turning groove 10 to when γ becomes 0°.

[0059] In the range from the turning starting point of the turning groove 10 to the point where γ becomes 0°, the tangent point a between the turning groove 10 of block 4 and the ball 3 is arranged on the line J or at a position closer to the track component 2 than the line J, thereby increasing the resultant force component B in the track direction of the turning groove 10.

[0060] Of a pair of side surfaces 11 and 12 on the outer side of the rolling groove 7 of the track component 2, the side surface 11 on the one side in contact with the ball 3 protrudes toward the block 4 side more than the other side surface 12 not in contact with the ball 3, so it is easy for the resultant force component B to act on the ball 3 in the track direction.

[0061] Since the rolling groove 8 and the turning groove 10 are continuously formed in the block 4 of the single structure, they can be connected seamlessly. Therefore, the movement of the ball 3 can be improved.

[0062] It should be noted that the present invention is not limited to being embodied in the above-described embodiment, and can be embodied in other embodiments within the scope of the gist of the present invention.

[0063] For example, in the above-mentioned embodiment, rolling grooves and turning grooves are formed in a block of a single structure, but it is also possible that the block is composed of a block body and a cover member installed on the end face of the block body, the rolling groove is formed in the block body, and the turning groove is formed in the cover member.

[0064] In the above-mentioned embodiment, an example in which the balls are fully loaded has been described, but spacers may be interposed between the balls.

[0065] In the above embodiment, an example of an outer block type linear guide in which a block having a substantially U-shaped cross section crosses a rail member is described, but an inner block type linear guide in which an inner block is arranged in an outer rail having a substantially U-shaped cross section may also be used.

[0066] In the above-mentioned embodiment, an example in which the motion guide device is a linear guide has been described, but the motion guide device may also be a ball spline.

[0067] This specification is based on Japanese Patent Application No. 2022-109425 filed on July 7, 2022. The entire contents are incorporated herein.

[0068] Description of Reference Numerals

[0069] 1: Motion guide device, 2: Track member, 3: Ball, 4: Block, 7: Rolling groove of track member, 8: Rolling groove of block, 9: Return groove (return part), 10: Turning groove (turning part), 11: Side of one side of the outer side of the rolling groove of track member, 12: Side of the other side of the outer side of the rolling groove of track member, e: Effective end, O: Center of ball, H: Line connecting the effective end e of the rolling groove of track member with the center O of the ball on the rolling groove of track member, G: Center line of the rolling groove of track member, α: Clamping angle of track member side, a: The point of tangency between the turning groove of the block and the ball, I: the line connecting the point of tangency a between the turning groove of the block and the ball and the center O of the ball on the rolling groove of the track component, β: the block side clamping angle, J: the line passing through the center O of the ball and being orthogonal to the center line G of the rolling groove of the track component, k: the point of tangency between the contour curve of the cross section of the track component and the ball, L: the line connecting the contour curve of the cross section of the track component with the point of tangency k of the ball and the center O of the ball, γ: the shape angle of the side surface of the track component, M: the line connecting the point of tangency a between the turning groove of the block and the ball and the center O of the ball, δ: the block side clamping angle.

Claims

1. A motion guiding device, wherein: The motion guiding device comprises: A track member having a rolling groove extending in a length direction; A block having a rolling groove opposite to the rolling groove of the track member, a return portion, and a turning portion connected to the rolling groove and the return portion; as well as A plurality of balls are arranged in a rolling path between the rolling groove of the track member and the rolling groove of the block, the return portion, and a circulation path of the turning portion. The ball is clamped between the wall surface of the rolling groove of the track member and the wall surface of the turning groove of at least a part of the turning portion of the block to change the track of the ball after moving in the rolling path. The track member side clamping angle formed by the line connecting the effective end of the rolling groove of the track member and the center of the ball on the rolling groove of the track member and the center line of the rolling groove of the track member is α, The block-side clamping angle formed by the line connecting the tangent point of the turning groove of the block and the ball and the center of the ball on the rolling groove of the track member and the center line of the rolling groove of the track member is β, At this time, α+β<180° is satisfied.

2. The motion guiding device according to claim 1, characterized in that: The point of contact between the turning groove of the block and the ball is arranged on a line that passes through the center of the ball and is perpendicular to the center line of the rolling groove of the track member or at a position closer to the track member than the line.

3. The motion guiding device according to claim 1 or 2, characterized in that: The shape angle of the side surface of the track member formed by the line connecting the tangent point of the profile curve of the cross section of the track member with the ball and the center of the ball and the center line of the rolling groove of the track member is set to γ, The block-side clamping angle formed by the line connecting the tangent point of the turning groove of the block and the ball and the center of the ball and the center line of the rolling groove of the track member is δ, At this time, within the range from the turning start point of the turning groove of the block to the time when γ becomes 0°, γ+δ<180° is satisfied.

4. The motion guiding device according to claim 3, characterized in that: In the range from the turning starting point of the turning groove of the block to the point where γ becomes 0°, the tangent point of the turning groove of the block and the ball is arranged on a line passing through the center of the ball and perpendicular to the center line of the rolling groove of the track component or at a position closer to the track component than the line.

5. The motion guiding device according to claim 1 or 2, characterized in that: Of a pair of side surfaces on the outer sides of the rolling groove of the track member, one side surface that contacts the ball protrudes toward the block more than the other side surface that does not contact the ball.

6. The motion guiding device according to claim 1 or 2, characterized in that: At least the rolling groove and the turning groove are continuously formed in the block of the single structure.

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