Motion guiding device

Abstract

Provided is a motion guide device capable of substantially approaching a rolling path and / or a return section in a tangent line even if at least a portion of a turning section is a three-dimensional and complicated three-dimensional trajectory. A three-dimensional trajectory of at least a portion of the turning portion is formed on the basis of a cross-section trajectory curve (14) in an XZ cross-section of the motion guide device and a length trajectory curve (15) drawn on a virtual plane VP in which the longitudinal direction of the motion guide device is the Y-axis and the trajectory length (omega) from the turning start point (A) of the cross-section trajectory curve (14) is the length (omega) of the W-axis. The X and Z coordinates of the three-dimensional track are the X and Z coordinates of the cross-section track curve (14). The Y-coordinate of the three-dimensional orbit is the Y-coordinate of the length orbit curve (15) in which the omega of the W-axis of the virtual plane VP is set as a variable.

Description

Technical Field

[0001] The invention relates to a motion guiding device with a three-dimensional track at a turning part. Background Art

[0002] There is known a motion guide device for guiding the linear motion or curved motion of a movable body such as a workbench (see Patent Document 1). The motion guide device includes a track member and a block that can move relative to the track member. A rolling path is formed between the rolling portion of the track member and the rolling portion of the block. A circulation path is composed of the rolling path, a return portion, and a turning portion connected to the rolling path and the return portion. A plurality of rolling elements are arranged in the circulation path.

[0003] In a common motion guide device, the track of the rolling path is a straight line. The track of the return part is also a straight line. The track of the turning part connected to the rolling path and the return part is an arc. The track of the turning part of the motion guide device observed along the length direction (Y direction), that is, the track of the turning part in the XZ section of the motion guide device is a straight line.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-197296 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, if Figure 8 As shown in (a), the track of the turning portion in the XZ cross section of the motion guide device may be curved due to the constraints of the shape of the track member and the shape of the turning portion. In this case, the track of the turning portion becomes a three-dimensional and complex track.

[0009] The inventors considered forming a three-dimensional and complex three-dimensional track as follows. Figure 8 The track curve of the turning portion in the XZ cross section shown in (a) (cross section track curve 21) is as follows Fig. 9 As shown in FIG. 2 , the curved surface 22 is drawn by sweeping along the Y-axis direction. Figure 8 The track curve 23 (length track curve) of the turning portion in the YZ cross section shown in (b) is as follows Fig. 9 As shown in FIG. 1 , a curved surface 24 is drawn by sweeping along the X-axis direction ( Fig. 9 In addition, the two curved surfaces 22 and 24 are combined, and the curve 25 where the two curved surfaces 22 and 24 intersect is set as a three-dimensional track. Figure 8 (a) Figure 8 (b) Fig. 9In the figure, 31 is a track component, 32 is a block, 33 is a rolling element, 34 is a starting point of a turning portion, 35 is an end point of a turning portion, 36 is a track of a rolling path, and 37 is a track of a return portion.

[0010] However, the three-dimensional track 25 of the turning portion formed in this way has a problem that the tangent lines are discontinuous at the starting point 34 and the end point 35 with respect to the straight line of the track 36 that becomes the rolling path and the straight line of the track 37 that becomes the return portion. Therefore, there is a possibility that the movement of the rolling element is deteriorated, the repeated durability of the turning portion is reduced, and noise is generated.

[0011] 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 that can approach at least one of a rolling path and a return portion substantially tangentially even if at least a part of a turning portion is a three-dimensional and complex three-dimensional track.

[0012] Solutions to Solve Problems

[0013] In order to solve the above-mentioned problems, the present invention relates to a motion guiding device, comprising: a track component; a block, which can move relative to the track component; and a plurality of rolling elements, which are arranged in a rolling path, a return portion, and a turning portion connected to the rolling path and the return portion between the rolling portion of the track component and the rolling portion of the block, wherein a three-dimensional track of at least a portion of the turning portion is formed based on a cross-sectional track curve in an XZ cross-section of the motion guiding device and a length track curve drawn on an imaginary plane with the length direction of the motion guiding device set as the Y-axis and the track length ω of the cross-sectional track curve from the starting point of the turn set as the length ω of the W-axis, the X and Z coordinates of the three-dimensional track are the X and Z coordinates of the cross-sectional track curve, and the Y coordinate of the three-dimensional track is the Y coordinate of the length track curve with the ω of the W-axis of the imaginary plane set as a variable.

[0014] Effects of the Invention

[0015] According to the present invention, even if at least a part of the turning portion is a three-dimensional and complex three-dimensional track, it can be substantially tangentially close to at least one of the rolling path and the return portion. Therefore, the movement of the rolling element can be improved, the repeated durability of the turning portion can be improved, and the noise can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a perspective view of a motion guide device according to one embodiment of the present invention.

[0017] Figure 2 (a) is a top view of the motion guide device of this embodiment, Figure 2 (b) is a side view.

[0018] Figure 3It is a front view of the motion guide device of this embodiment.

[0019] Figure 4 (a) is a bottom side perspective view of the block of this embodiment, Figure 4 (b) is a perspective view of the upper surface side of the block of this embodiment after being turned over.

[0020] Figure 5 This is a schematic diagram showing a method for processing a block according to the present embodiment.

[0021] Figure 6 (a) shows a cross-sectional track curve of this embodiment, Figure 6 (b) shows the length track curve of this embodiment.

[0022] Figure 7 (a) shows a cross-sectional track curve of this embodiment, Figure 7 (b) shows the length track curve of this embodiment.

[0023] Figure 8 1 is a diagram for explaining a method for forming a turning portion of a motion guide device of a comparative example ( Figure 8 (a) shows the cross-sectional orbit curve in the XZ section, Figure 8 (b) shows the length track curve in the YZ section).

[0024] Fig. 9 It is a diagram for explaining a method of forming a turning portion of a motion guide device according to a comparative example (a perspective view showing an example of combining two swept curved surfaces). DETAILED DESCRIPTION

[0025] 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.

[0026] Figure 1 A perspective view showing a motion guide device 1 according to an embodiment of the present invention. Figure 2 A plan view and a side view of the motion guide device 1 according to the present embodiment are shown. Figure 3 A front view of the motion guide device 1 according to the present embodiment is shown.

[0027] 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 as rolling bodies so as to be able to roll. The block 4 has a circulation path 5 for circulating the plurality of balls 3. The circulation path 5 is composed of a rolling path 13 between the rolling portion 7 of the track member 2 and the rolling portion 8 of the block 4, a return portion 9, and a turning portion 10.

[0028] It should be noted that, hereinafter, the length direction of the track member 2, that is, the moving direction of the block 4 is set as the Y axis, the height direction is set as the Z axis, and the horizontal direction is set as the X axis.

[0029] 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 portion 7 extending in the length direction is formed on the side surface 2b of the track member 2. The rolling portion 7 is a groove in the shape of a pointed arch. The rolling portion 7 can also be a groove 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 portions 7 can be appropriately set to 2, 4, etc. In addition, the configuration of the rolling portion 7 can also be appropriately set.

[0030] like Figure 3 As shown, the block 4 is roughly U-shaped in cross section and is arranged to cross the track member 2. The block 4 has a web portion 4a opposite to the upper surface 2a of the track member 2, and a pair of sleeve portions 4b hanging down from both ends of the web portion 4a in the left and right directions and opposite to the side surface 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 in FIG. 1 , a rolling portion 8, a return portion 9, and a turning portion 10 are formed in the block 4. The rolling portion 8 of the block 4 is opposite to the rolling portion 7 of the track member 2.

[0031] 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 portion 8 is formed on the sleeve portion 4b of the block 4. The rolling portion 8 is a groove in a pointed arch shape. The rolling portion 8 may also be a groove in a single arc shape.

[0032] A return portion 9 is formed on the web portion 4a of the block 4 substantially parallel to the rolling portion 8. The return portion 9 is a groove opened toward the track member 2. It should be noted that the return portion 9 may also be a through hole.

[0033] The turn portion 10 connecting the block 4 with the rolling portion 8 and the return portion 9 is formed from the sleeve portion 4b to the web portion 4a of the block 4. The turn portion 10 is a groove opened toward the track member 2. It should be noted that the turn portion 10 may also be a through hole.

[0034] like Figure 3 As shown, in the motion guide device 1 of the present embodiment, of a pair of side surfaces 11 and 12 on the outer side of the rolling portion 7 of the track member 2, the upper side surface 11 in the Z direction that contacts the ball 3 protrudes toward the block 4 side more than the lower side surface 12 that does not contact the ball 3. The cross-sectional shape of the upper side surface 11 of the track member 2 is roughly arc-shaped. The turning portion 10 of the block 4 is bent along the upper side surface 11. In addition, the turning portion 10 extends in a straight line along the upper surface 2a of the track member 2. That is, the turning portion 10 is composed of a combination of an arc and a straight line, and is roughly J-shaped.

[0035] like Figure 5 As shown, the rolling portion 8 of the block 4 (see Figure 4 ), the return portion 9, and the turning portion 10 are continuously formed on the block 4 using a cutting tool 19 such as an end mill. The connection between the rolling portion 8, the turning portion 10, and the return portion 9 is seamless and does not have a seam. It should be noted that the cutting tool 19 is not limited to the end mill. In addition, in addition to cutting, the rolling portion 8, the turning portion 10, and the return portion 9 can also be continuously formed on the block 4 by plastic processing such as forging and stamping.

[0036] Again Figure 1 as well as Figure 2 As shown, a plurality of balls 3 are arranged in the circulation path 5 composed of the rolling path 13, the return portion 9, and the turning portion 10. When the block 4 is moved relative to the track member 2, the balls 3 roll in the rolling path 13. The balls 3 moved to one end of the rolling path 13 are guided to the turning portion 10, and after the return portion 9 moves in the opposite direction, they are guided to the other end of the rolling path 13 from the other turning portion 10.

[0037] The rolling path 13 has a straight track 13a. The return portion 9 also has a straight track 9a. The turning portion 10 has a three-dimensional and complex three-dimensional track 10a. It should be noted that the tracks 13a, 9a, and 10a of the rolling path 13, the return portion 9, and the turning portion 10 are the center lines of these paths. In the return portion 9, there is a tiny gap between the ball 3 and the wall surface of the return portion 9. The track 9a of the return portion 9 is the center line of the return portion 9. In a part of the rolling path 13 and the turning portion 10, the ball 3 is sandwiched between the track member 2 and the block 4 and moves. The tracks 13a and 10a of a part of the rolling path 13 and the turning portion 10 can also be set as the line drawn by the center of the moving ball 3.

[0038] The following describes a method for forming the three-dimensional track 10a of the turning portion 10. The three-dimensional track 10a of the turning portion 10 is based on the cross-sectional track curve 14 in the XZ cross section of the motion guide device 1 (see Figure 6 (a)), and the length track curve 15 (refer to Figure 6 (b) is formed.

[0039] like Figure 6 As shown in (a), the cross-sectional track curve 14 is a curve showing the actual trajectory of the track in which the ball 3 circulates in the XZ cross-section of the motion guide device 1. A is the starting point of the turn, and C is the end point of the turn. The cross-sectional track curve 14 is predetermined by the constraints of the shape of the track member 2, the constraints of the shape of the turning portion 10, and the like. For example, in the present embodiment, the cross-sectional track curve 14 is predetermined by the constraints of the shape of the track member 2, and is formed by connecting a single arc with a straight line in such a manner that the ball 3 can move along the side 2b and the upper surface 2a of the track member 2. Of course, the cross-sectional track curve 14 is not limited to this, and may be formed by connecting a plurality of arcs with different curvatures instead of a single arc. In addition, instead of connecting an arc with a straight line, the cross-sectional track curve 14 may be formed only by an arc, an ellipse, a clothoid curve, or a spline curve.

[0040] like Figure 6 As shown in (b), the length track curve 15 is a curve that reverses the track direction by 180°. A is the starting point of the turn, and C is the end point of the turn. The length track curve 15 is connected to the track 13a of the rolling path 13 and the track 9a of the return part 9. The track 13a of the rolling path 13 and the track 9a of the return part 9 are straight lines and parallel to the Y axis. The turning track width α of the length track curve 15, that is, the distance between the track 13a of the rolling path 13 and the track 9a of the return part 9, is equal to the total track length α of the cross-sectional track curve 14 (refer to Figure 6 (a)).

[0041] The Y axis of the virtual plane VP is the length direction of the motion guide device 1, that is, the relative movement direction of the block 4. The W axis of the virtual plane VP is different from the Z axis of the motion guide device 1. The variable ω of the W axis is not the length of the Z axis direction of the motion guide device 1, but the track length ω of the cross-sectional track curve 14 from the turning starting point A (refer to Figure 6 For example, when the cross-sectional track curve 14 is an arc, the track length ω is the length of the arc.

[0042] The length track curve 15 is, for example, a curve with continuous tangents, such as a single arc, etc. The length track curve 15 may also be, for example, a curve with continuous tangents, such as an ellipse, a clothoid curve, or a spline curve.

[0043] The length track curve 15 is connected to the track 13a of the rolling path 13 in a substantially tangentially continuous manner at the turning starting point A. In addition, it is connected to the track 9a of the return portion 9 in a substantially tangentially continuous manner at the turning end point C. It should be noted that the length track curve 15 is preferably connected to both the track 13a of the rolling path 13 and the track 9a of the return portion 9 in a tangentially continuous manner, but it can also be connected to at least one of the track 13a of the rolling path 13 and the track 9a of the return portion 9 in a tangentially continuous manner.

[0044] When the horizontal direction of the motion guidance device 1 is set to the X coordinate, the height direction is set to the Z coordinate, and the length direction is set to the Y coordinate, the coordinates of the three-dimensional track 10a of the turning portion 10 use the track length ω of the cross-sectional track curve 14 from the turning starting point A, and are represented by the following continuous X, Y, and Z coordinates.

[0045] (Formula 1)

[0046] (X, Y, Z) = (F X (ω), F Y (ω), F Z (ω) (1)

[0047] Here, the X and Z coordinates of the three-dimensional track 10a are the X and Z coordinates of the cross-sectional track curve 14 (F X (ω), F Z The Y coordinate of the three-dimensional track 10a is the Y coordinate of the length track curve 15 (F Y (ω)).

[0048] An example of a method for forming the three-dimensional track 10a is described below. The X and Z coordinates of the three-dimensional track 10a are as follows: Figure 6 As shown in (a), the coordinates of the cross-sectional track curve 14 are (F X (ω), F Z (ω)).

[0049] like Figure 7 As shown in (a) of FIG. 1 , when the cross-sectional trajectory curve 14 is formed by connecting a circular arc and a straight line, the X and Z coordinates of the cross-sectional trajectory curve 14 are expressed as follows.

[0050] (Formula 2)

[0051] (X, Z) = (F X (ω), FZ (ω) (2)

[0052] In the range A to B,

[0053]

[0054] In the B~C interval,

[0055]

[0056] Here, A is the starting point of the turn, B is the curvature change point in the cross-section track curve, and C is the end point of the turn. ω is the track length from the starting point A of the turn, which is a variable that changes from 0 to α. θ is the start angle of the turn, R1 is the radius of the cross-section track, and α is the total length of the cross-section track.

[0057] The Y coordinate of the three-dimensional track 10a is as follows Figure 6 As shown in (b), the Y coordinate of the length track curve 15 (F Y (ω)).

[0058] like Figure 7 As shown in (b) of FIG. 1 , when the length track curve 15 is formed by a single arc, the Y coordinate of the three-dimensional track 10 a is expressed as follows.

[0059] (Formula 3)

[0060] Y=F Y (ω) (3)

[0061] In the range A to C,

[0062]

[0063] Here, R2 is the length orbit radius, R2=α / 2.

[0064] According to (2), F X (ω)F Z (ω), F of (3) Y (ω) The X, Y, and Z coordinates of the three-dimensional track 10a are obtained by taking the track length ω from the turning starting point A as a variable. It should be noted that F in formula (3) W Although not used in obtaining the coordinates of the three-dimensional trajectory 10 a , they are described for reference.

[0065] exist Figure 11 shows a three-dimensional track 10a of the turning portion 10 formed based on the cross-sectional track curve 14 and the length track curve 15. By forming the three-dimensional track 10a in this way, even if the three-dimensional track 10a is a three-dimensional and complex track, it can be connected to the track 13a of the rolling path 13 at the turning starting point A thereof in a substantially tangentially continuous manner. In addition, it can be connected to the track 9a of the return portion 9 at the turning end point C thereof in a substantially tangentially continuous manner.

[0066] The configuration of the motion guide device 1 according to the present embodiment has been described above. The motion guide device 1 according to the present embodiment has the following effects.

[0067] The three-dimensional track 10a of at least a portion of the turning portion 10 is formed based on the cross-sectional track curve 14 and the length track curve 15 of the motion guide device 1. Therefore, even if at least a portion of the turning portion 10 is a three-dimensional and complex three-dimensional track, it can be substantially tangentially close to at least one of the rolling path 13 and the return portion 9. Therefore, the movement of the ball 3 can be improved, the repeated durability of the turning portion 10 can be improved, and the noise can be suppressed.

[0068] On the imaginary plane VP, the length track curve 15 is connected to at least one of the track 13a of the rolling path 13 and the track 9a of the return portion 9 in a tangentially continuous manner, so that the three-dimensional track 10a of the turning portion 10 can be connected to at least one of the rolling path 13 and the return portion 9 in a tangentially continuous manner.

[0069] Since the turning track width (α) of the length track curve 15 is equal to the total track length (α) of the cross-sectional track curve 14 , the three-dimensional track 10 a of the turning portion 10 can be smoothly formed within the total length.

[0070] Since at least the rolling portion 8 and the turning portion 10 are continuously formed in the block 4 of the single structure, they can be seamlessly connected.

[0071] 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 present invention.

[0072] In the above embodiment, the cross-sectional track curve in the XZ cross section of the motion guide device is composed of curves and straight lines, but it can also be composed of only curves. In addition, in the above embodiment, the length track curve in the virtual plane of the motion guide device is composed of only curves, but it can also include a straight line in part.

[0073] In the above-mentioned embodiment, the rolling part and the turning part are formed in the block of a single structure, but the block may be formed by using a block body and a cover member mounted on the end surface of the block body, the rolling part is formed in the block body, and the turning part is formed in the cover member. In this case, as with a conventional linear guide, two, four, etc. rolling parts may be formed in the block body, two, four, etc. turning parts may be formed in the cover member, and the return part of the block body may be arranged on the sleeve of the block body. In addition, the return part may be set as a through hole in a manner that the return part of the block body has a closed cross section, and the cover member may be composed of an end plate and an inner part in a manner that the turning part of the cover member has a closed cross section.

[0074] In the above embodiment, an example of full packing of balls is described, but a spacer may be interposed between the balls. In addition, an example of rolling elements being balls is described, but the rolling elements may be rollers.

[0075] 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.

[0076] 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.

[0077] This specification is based on Japanese Patent Application No. 2022-109426 filed on July 7, 2022. The entire contents are incorporated herein.

[0078] Description of Reference Numerals

[0079] 1: motion guiding device, 2: track component, 3: ball (rolling element), 4: block, 7: rolling part of track component, 8: rolling part of block, 9: return part, 9a: track of return part, 10: turning part, 10a: three-dimensional track of turning part, 13: rolling path, 13a: track of rolling path, 14: cross-sectional track curve, 15: length track curve, VP: imaginary plane.

Claims

1. A motion guiding device, comprising: Track components; a block capable of relative movement relative to the track member; and A plurality of rolling elements are arranged on a rolling path between the rolling portion of the track member and the rolling portion of the block, a return portion, and a turning portion connected to the rolling path and the return portion, in, A three-dimensional track of at least a portion of the turning portion is formed based on a cross-sectional track curve in an XZ cross-section of the motion guide device and a length track curve drawn on an imaginary plane in which the length direction of the motion guide device is set as the Y axis and the track length ω of the cross-sectional track curve from the starting point of the turn is set as the length ω of the W axis, The X, Z coordinates of the three-dimensional track are the X, Z coordinates of the cross-sectional track curve, The Y coordinate of the three-dimensional trajectory is the Y coordinate of the length trajectory curve with the ω of the W axis of the virtual plane as a variable.

2. The motion guiding device according to claim 1, characterized in that: On the imaginary plane, the length track curve is connected to at least one of the track of the rolling path and the track of the return portion in a continuous tangential manner.

3. The motion guiding device according to claim 1 or 2, characterized in that: The turning track width (α) of the length track curve is equal to the total track length (α) of the cross-section track curve.

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

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