Linear motion guide unit

Abstract

The linear motion guide unit comprises a first track base and a second track base, the second track base moving linearly relative to the first track base in a first direction. The linear motion guide unit includes a plurality of rollers, a holder for holding the plurality of rollers, a rotatably supported pinion, a first rack provided with a plurality of first rack teeth that mesh with the external teeth, and a second rack provided with a plurality of second rack teeth that mesh with the external teeth. The holder includes a roller holding area and a pinion holding area. The pinion includes a disc portion provided with a support recess that is recessed in the thickness direction, and a plurality of external teeth arranged at circumferential intervals on the outer surface of the disc portion. The pinion housing is surrounded by a housing wall. The housing wall is provided with support projections that protrude toward the pinion and fit into the support recess, so as to rotatably support the pinion disposed within the pinion housing.

Description

Technical Field

[0001] The present disclosure relates to a linear guide unit.

Background Art

[0002] Linear guide devices including a pinion and a rack for guiding a cage that holds rolling elements are known (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the linear guide devices disclosed in Patent Document 1 and Patent Document 2, the mechanism for holding the pinion is complex and requires a so-called forced extraction process in the manufacturing process. For this reason, it becomes difficult to mold the mechanism for holding the pinion, leading to a decrease in productivity. Further, according to the linear guide device disclosed in Patent Document 3, new parts are required to hold the pinion. In such a configuration, the number of parts increases, and also in this case, productivity decreases, which is not preferable.

[0005] Therefore, one of the objectives is to provide a linear guide unit that can improve productivity while reducing the number of parts.

Means for Solving the Problems

[0006] A linear motion guide unit according to this disclosure comprises a first guide bed extending in a first direction which is the longitudinal direction, and a second guide bed extending in the first direction and positioned opposite to the first guide bed in a second direction which is perpendicular to the first direction, wherein the second guide bed performs linear motion relative to the first guide bed in the first direction. The linear motion guide unit includes a plurality of rollers alternately arranged at intervals in the first direction so that their rolling axes are perpendicular, a holder positioned between the first and second guide beds in the second direction, having a plurality of pockets for accommodating each roller at intervals in the first direction, and holding the plurality of rollers, a pinion with a plurality of external teeth on its outer circumference, positioned between the first and second guide beds in the second direction and rotatably supported, a first rack attached to the outer surface of the first guide bed and provided with a plurality of first rack teeth that mesh with the external teeth, and a second rack attached to the outer surface of the second guide bed and provided with a plurality of second rack teeth that mesh with the external teeth. The retainer includes a roller retaining region having pockets for holding rollers, and a pinion retaining region positioned adjacent to the roller retaining region in a first direction, and having a pinion housing portion for housing a pinion such that its external teeth mesh with the second rack teeth. The pinion includes a disc portion having support recesses that are recessed in the thickness direction, and a plurality of external teeth arranged at circumferential intervals on the outer surface of the disc portion. The pinion housing portion is surrounded by a housing wall. The housing wall is provided with support projections that protrude toward the pinion and fit into the support recesses, so as to rotatably support the pinion housed within the pinion housing portion. [Effects of the Invention]

[0007] The linear motion guide unit described above makes it possible to improve productivity while reducing the number of parts. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view of the linear motion guide unit in Embodiment 1 of this disclosure. [Figure 2] Figure 2 is a schematic plan view of the linear motion guide unit shown in Figure 1. [Figure 3]Figure 3 is a schematic front view of the linear motion guide unit shown in Figure 1. [Figure 4] Figure 4 is a schematic side view of the linear motion guide unit shown in Figure 1. [Figure 5] Figure 5 is a schematic cross-sectional view of the linear motion guide unit shown in Figure 1. [Figure 6] Figure 6 is a schematic cross-sectional view of the linear motion guide unit shown in Figure 1. [Figure 7] Figure 7 is an enlarged view showing a portion of the linear motion guide unit shown in Figure 1. [Figure 8] Figure 8 is a schematic perspective view showing the linear motion guide unit shown in Figure 1 with the second track platform, which will be described later, removed. [Figure 9] Figure 9 is a schematic plan view of the linear motion guide unit shown in Figure 8. [Figure 10] Figure 10 is a schematic side view of the linear motion guide unit shown in Figure 8. [Figure 11] Figure 11 is a schematic perspective view of the first rack. [Figure 12] Figure 12 is a schematic perspective view showing the appearance of the pinion. [Figure 13] Figure 13 is a schematic front view of the pinion shown in Figure 12. [Figure 14] Figure 14 is a schematic perspective view of a holder holding multiple rollers. [Figure 15] Figure 15 is a schematic perspective view showing a magnified portion of the retainer shown in Figure 14. [Figure 16] Figure 16 is a schematic plan view showing an enlarged view of the pinion holding region. [Figure 17] Figure 17 is a schematic perspective view showing a magnified portion of the containment wall. [Figure 18] Figure 18 is a schematic cross-sectional view showing a magnified view of the pinion holding region. [Figure 19] Figure 19 is a schematic perspective view of the pinion being housed within the pinion housing. [Modes for carrying out the invention]

[0009] [Overview of the Embodiment] The linear guide unit of the present disclosure includes a first rail base extending in a first direction which is the longitudinal direction, and a second rail base extending in the first direction and arranged to face the first rail base in a second direction which is a direction orthogonal to the first direction. The second rail base performs a linear motion relative to the first rail base in the first direction. The linear guide unit includes a plurality of rollers alternately arranged at intervals in the first direction such that their rolling axes are orthogonal to each other, a plurality of pockets provided at intervals in the first direction between the first rail base and the second rail base in the second direction for accommodating each roller, a cage for holding the plurality of rollers, a pinion provided with a plurality of external teeth on its outer periphery and arranged between the first rail base and the second rail base in the second direction and rotatably supported, a first rack provided with a plurality of first rack teeth attached to the outer peripheral surface of the first rail base and meshing with the external teeth, and a second rack provided with a plurality of second rack teeth attached to the outer peripheral surface of the second rail base and meshing with the external teeth. The cage includes a roller holding region provided with pockets for holding the rollers, and a pinion holding region arranged adjacent to the roller holding region in the first direction and provided with a pinion accommodating portion for accommodating the pinion such that the external teeth mesh with the second rack teeth. The pinion includes a disk portion provided with a support recess recessed in the thickness direction, and a plurality of external teeth arranged at intervals in the circumferential direction on the outer peripheral surface of the disk portion. The pinion accommodating portion is surrounded by an accommodating wall surface. The accommodating wall surface is provided with a support protrusion protruding toward the pinion side so as to rotatably support the pinion arranged in the pinion accommodating portion and fitted into the support recess.

[0010] Regarding the linear guide unit in which the second rail base performs a linear motion relative to the first rail base, a mechanism for smoothly performing the linear motion is required. The linear guide unit can prevent the displacement of the position of the cage that holds the rollers by using a pinion, a first rack, and a second rack. Therefore, the linear motion can be properly guided. Note that the external teeth of the pinion are arranged between the first rail base and the second rail base, and the first rack and the second rack are respectively attached to the outer peripheral surfaces of the first rail base and the second rail base. Therefore, the pinion can be arranged in a so-called vertical position. Then, the external teeth of the pinion can be directed outside the rail base, and the rack can be provided outside the rail base. As a result, the diameter of the roller can be increased compared to the case where the rack is arranged inside the rail base, and the load capacity can be increased. Further, the cage includes a roller holding region that holds the rollers and a pinion holding region provided with a pinion accommodating portion that accommodates the pinion. And, on the accommodating wall surface surrounding the pinion accommodating portion, a support protrusion that protrudes toward the pinion side in the pinion accommodating portion so as to rotatably support the pinion accommodated in the pinion accommodating portion and is fitted into the support recess is provided. Then, in order to realize a mechanism for holding the pinion, there is no need to provide a new component. Also, the structure for rotatably supporting the pinion can be simplified, and since it can be molded without forced extraction, the molding of the cage can be facilitated. As described above, according to the linear guide unit, while reducing the number of parts, the productivity can be improved.

[0011] In the linear guide unit, the support protrusion may be cylindrical. The support recess may be recessed in a round hole shape. By doing so, it becomes easy to rotatably support the pinion. Therefore, the second rail base can be linearly moved more smoothly.

[0012] In the linear motion guide unit described above, the support recess may be a through hole that penetrates in the thickness direction of the pinion. By doing so, the support recess can be easily formed, and the support projection can be securely fitted into the support recess. Therefore, the pinion can be supported in a rotatable manner more easily.

[0013] In the linear motion guide unit described above, the pinion is provided in the outer peripheral region of the support recess, and may include a thicker portion than other regions. By doing so, the rigidity of the pinion, particularly the rigidity around the support recess, can be increased. Therefore, the risk of pinion failure can be reduced, and the second track can be moved linearly stably over a long period of time.

[0014] In the linear motion guide unit described above, the support projection may include a chamfered portion such that, when viewed in the thickness direction of the pinion arranged within the pinion housing, the amount of protrusion at the center of the support projection is greater than the amount of protrusion at the periphery of the support projection. By doing so, the chamfer can be used to make it easier to fit the support projection into the support recess. Therefore, assembly can be improved.

[0015] In the above linear motion guide unit, the roller holding area and the pinion holding area may be integrated into a single unit. This reduces the number of parts and improves ease of assembly.

[0016] In the linear motion guide unit described above, the retainer may be made of resin. By doing so, the elastic deformation of the retainer can be effectively utilized to make it easier to fit the support projection into the support recess. Furthermore, mass production of the pinion can be achieved by molding using a mold. Therefore, productivity can be improved.

[0017] In the linear motion guide unit described above, the housing wall may include a first wall located on one side in the thickness direction of the pinion disposed within the pinion housing, and a second wall located on the other side in the thickness direction of the pinion disposed within the pinion housing. The support projection may be provided so as to extend from at least one of the first wall and the second wall. In this way, the support projection can be provided so as to extend from at least one of the opposing first wall and second wall. Therefore, when housing the pinion in the pinion housing, the support projection can be easily fitted into the support recess. Thus, assembly can be improved.

[0018] In the linear motion guide unit described above, the support projections may be provided on both the first and second wall surfaces. By doing so, the pinion can be supported by the support projections extending from both the first and second wall surfaces. Therefore, the pinion can be rotated more stably, and the second raceway can be made to move smoothly in a linear fashion.

[0019] In the linear motion guide unit described above, the pinion holding region may be provided with a first notch that is recessed in the thickness direction of the pinion placed in the pinion housing, reducing the thickness from the outer circumference. By doing so, the first notch makes the pinion holding region more elastically deformable, making it easier to fit the support projection into the support recess when housing the pinion in the pinion housing. Therefore, assembly can be improved.

[0020] In the linear motion guide unit described above, the pinion holding region may be provided with a second notch cut out on a surface perpendicular to the thickness direction of the pinion placed within the pinion housing, which slopes from the outer circumference to the outer edge of the pinion housing. By doing so, the second notch can be used as a guide when housing the pinion in the pinion housing, and the second notch makes the pinion holding region more elastically deformable, making it easier to fit the support projection into the support recess. Therefore, assembly ease can be further improved.

[0021] [Specific examples of embodiments] Next, an example of a specific embodiment of the linear motion guide unit of this disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals and their descriptions will not be repeated.

[0022] (Embodiment 1) First, Embodiment 1, which is an embodiment of the present disclosure, will be described. Figure 1 is a schematic perspective view of the linear guide unit in Embodiment 1 of the present disclosure. Figure 2 is a schematic plan view of the linear guide unit shown in Figure 1. Figure 2 is a view in the direction of arrow II shown in Figure 1. Figure 3 is a schematic front view of the linear guide unit shown in Figure 1. Figure 3 is a view in the direction of arrow III shown in Figure 1. Figure 4 is a schematic side view of the linear guide unit shown in Figure 1. Figure 4 is a view in the direction of arrow IV shown in Figure 1. Figures 5 and 6 are schematic cross-sectional views of the linear guide unit shown in Figure 1, respectively. Figure 5 is a schematic cross-sectional view when cut along the cross section indicated by VV in Figure 2. Figure 6 is a schematic cross-sectional view when cut along the cross section indicated by VI-VI in Figure 2. Figure 7 is an enlarged view showing a part of the linear guide unit shown in Figure 1. In Figure 7, the second guide platform and the second rack, which will be described later, are shown in a cut state. Figure 8 is a schematic perspective view showing the linear guide unit shown in Figure 1 with the second guide platform, which will be described later, removed. Figure 9 is a schematic plan view of the linear motion guide unit shown in Figure 8. Figure 9 is a view in the direction of arrow IX shown in Figure 8. Figure 10 is a schematic side view of the linear motion guide unit shown in Figure 8. Figure 10 is a view in the direction of arrow X shown in Figure 8. In the figures shown from Figure 1 onward, the direction indicated by arrow Y is the first direction (longitudinal direction) of the linear motion guide unit, the direction indicated by arrow X is the second direction (short direction) of the linear motion guide unit, and the direction indicated by arrow Z is the third direction (thickness direction) of the linear motion guide unit.

[0023] Referring to Figures 1 to 10, the linear motion guide unit 10a in Embodiment 1 includes a first guide base 11a, a second guide base 12a, a plurality of rollers 13a, a retainer 14a, a pinion 15a, a first rack 16a, and a second rack 17a. The first guide base 11a and the second guide base 12a each have a shape that extends in the longitudinal direction, which is the first direction (Y direction). The first guide base 11a and the second guide base 12a have the same shape. That is, the length in the X direction, Y direction, and Z direction of the first guide base 11a are equal to the length in the X direction, Y direction, and Z direction of the second guide base 12a, respectively. The second guide base 12a corresponds to a member obtained by inverting the first guide base 11a in the Z direction and X direction, respectively.

[0024] The second track platform 12a is positioned opposite the first track platform 11a in the second direction (X direction), which is perpendicular to the first direction. The linear motion guide unit 10a is a linear motion guide unit that allows the second track platform 12a to perform linear motion relative to the first track platform 11a in the first direction.

[0025] The first track bed 11a includes a first track surface 21a and a second track surface 22a on which the roller 13a rolls. The first track surface 21a and the second track surface 22a are each composed of planes extending in the longitudinal direction. The first track surface 21a is inclined at 45 degrees with respect to the XY plane and the YZ plane, respectively (see Figures 3 and 5 in particular). The second track surface 22a is also inclined at 45 degrees with respect to the XY plane and the YZ plane, respectively. The second track surface 22a is inclined at 90 degrees with respect to the first track surface 21a. A groove-shaped relief section 23a extending in the Y direction is provided between the first track surface 21a and the second track surface 22a.

[0026] One surface 24a in the X direction of the first raceway base 11a on the side where the first raceway surface 21a and the second raceway surface 22a are provided is parallel to the YZ plane and is positioned to face the surface 34a of the second raceway base 12a, which will be described later. The first raceway base 11a is provided with a plurality of circular through-holes 27a that are spaced apart in the longitudinal direction and penetrate from one surface 28a in the thickness direction (Z direction) to the other surface 29a in the thickness direction. In this embodiment, a total of four through-holes 27a are provided. The diameter of the through-holes 27a is larger on the side of one surface 28a than on the side of the other surface 29a. That is, the through-holes 27a have a stepped shape. These through-holes 27a can be used to attach the first raceway base 11a to other members, or to attach other members to the first raceway base 11a. Furthermore, the first track base 11a is recessed in the thickness direction from the surface 28a and has multiple mounting holes used when attaching the first rack 16a. In this embodiment, there are a total of four mounting holes spaced apart in the longitudinal direction and penetrate in the thickness direction. The mounting holes are located near each through hole 27a, avoiding the through hole 27a. The mounting holes are provided with screw threads.

[0027] The configuration of the second raceway 12a is the same as that of the first raceway 11a. This allows for the sharing of parts and improves productivity. Specifically, the second raceway 12a includes a first raceway surface 31a and a second raceway surface 32a on which the roller 13a rolls. The second raceway 12a is also provided with a relief section 33a with a configuration similar to that of the relief section 23a. One surface 34a in the X direction of the second raceway 12a on the side where the first raceway surface 31a and the second raceway surface 32a are provided is parallel to the YZ plane and is positioned opposite to surface 24a. The second raceway 12a is provided with a total of four round through-holes 37a that are spaced apart in the longitudinal direction and penetrate from one surface 38a in the thickness direction to the other surface 39a in the thickness direction. The diameter of the through-holes 37a is larger on the side of one surface 38a than on the side of the other surface 39a. In other words, the through hole 37a has a stepped shape. The second track base 12a also has multiple mounting holes that are recessed in the thickness direction from the surface 38a and are used when attaching the second rack 17a.

[0028] Next, the configuration of the roller 13a will be described. The roller 13a is a solid cylindrical shape. The roller 13a includes a rolling surface 41a and a pair of end faces 42a. The direction connecting the centers of the pair of end faces 42a is the direction of the rolling axis of the roller 13a. All of the rollers 13a are the same shape. The rollers 13a are arranged alternately with spacing in the longitudinal direction, which is the first direction, so that their rolling axes are perpendicular to each other. In this embodiment, the linear motion guide unit 10a includes 20 rollers 13a.

[0029] Next, the configuration of the first rack 16a will be described. Figure 11 is a schematic perspective view of the first rack 16a. Referring to Figure 11, the first rack 16a includes a flat plate-like portion 51a and a plurality of first rack teeth 52a provided at the end of the plate-like portion 51a. The plate-like portion 51a is provided with a plurality of through holes 53a that are spaced apart in the longitudinal direction and penetrate in the thickness direction, i.e., in the Z direction. In this embodiment, there are four through holes 53a. The first rack 16a is attached to the outer circumferential surface of the first raceway 11a, in this embodiment, to the surface 28a of the first raceway 11a, by bolts 54a using the through holes 53a. The plate-like portion 51a is provided with a plurality of notches 55a that are recessed in the X direction. In this embodiment, the notches 55a are cut out in an arc shape when viewed in the Z direction, and there are four of them. The four notches 55a are provided in positions where the through holes 27a are exposed when the first rack 16a is attached to the surface 28a of the first track base 11a. By forming these notches 55a, the through holes 27a are not blocked even after the first rack 16a is attached to the surface 28a of the first track base 11a, and the first track base 11a can be fixed in a predetermined position using the through holes 27a.

[0030] Multiple first rack teeth 52a mesh with the external teeth 73a of the pinion 15a. Multiple first rack teeth 52a are comb-shaped. Multiple first rack teeth 52a are provided to protrude in the Z direction. Multiple first rack teeth 52a are provided to protrude in the Z direction from the X-direction side end 56a of the plate-shaped portion 51a. The first rack teeth 52a are provided over the entire longitudinal area of ​​the plate-shaped portion 51a. The material of the first rack 16a may be resin, but considering strength, it may be made of metal, for example, steel plate.

[0031] The configuration of the second rack 17a is the same as that of the first rack 16a. The second rack 17a includes a plate-like portion 61a with through holes 63a and notches 65a, and a plurality of second rack teeth 62a provided on the side end 66a of the plate-like portion 61a. The second rack 17a is attached to and fixed to the second track base 12a by bolts 64a.

[0032] Next, the configuration of the pinion 15a will be described. Figure 12 is a schematic perspective view showing the external appearance of the pinion 15a. Figure 13 is a schematic front view of the pinion 15a shown in Figure 12. Figure 13 is a view in the direction of arrow XIII shown in Figure 12. Referring to Figures 12 and 13, the pinion 15a includes a disc portion 71a with a support recess 72a that is recessed in the thickness direction, and a plurality of external teeth 73a arranged at intervals in the circumferential direction on the outer surface of the disc portion 71a. In this embodiment, the support recess 72a is a through hole that penetrates the pinion 15a in the thickness direction (X direction) in a circular shape. The pinion 15a is provided in the region on the outer circumferential side of the support recess 72a and includes a thick-walled portion 74a in which the thickness of the pinion 15a is greater than in other regions. The thick-walled portion 74a is provided in an annular shape, connected in the circumferential direction. The thickness of the thick-walled portion 74a gradually increases from the outer circumferential side to the inner circumferential side. As shown in Figure 13, the thickened portion 74a is tapered.

[0033] Next, the configuration of the retainer 14a will be described. Figure 14 is a schematic perspective view of the retainer 14a holding multiple rollers 13a. Figure 15 is a schematic perspective view showing an enlarged portion of the retainer 14a shown in Figure 14. Referring together to Figures 14 and 15, the retainer 14a has a shape that extends in the longitudinal direction, which is the first direction. The retainer 14a holds multiple rollers 13a so that they can roll. The retainer 14a is made of resin. The retainer 14a is positioned between the first track base 11a and the second track base 12a in the short direction (X direction), which is the second direction.

[0034] The retainer 14a includes roller retaining regions 45a, 46a, which are provided with pockets 44a for holding rollers 13a, and a pinion retaining region 48a, which is provided with a pinion housing 81a for housing a pinion 15a. The roller retaining regions 45a, 46a are provided as a pair, divided in the longitudinal direction. The pinion retaining region 48a is arranged adjacent to the roller retaining regions 45a, 46a in the longitudinal direction (first direction). Specifically, the pinion retaining region 48a is arranged between the pair of roller retaining regions 45a, 46a, which are divided in the longitudinal direction. In this embodiment, the pinion retaining region 48a is provided in the center of the retainer 14a in the longitudinal direction, and the pair of roller retaining regions 45a, 46a are provided at both ends of the retainer 14a in the longitudinal direction. In other words, in the longitudinal direction, the pinion holding region 48a is sandwiched between a pair of roller holding regions 45a and 46a. The roller holding regions 45a and 46a and the pinion holding region 48a are integrally formed. That is, the retainer 14a is a single, integrated component and is not constructed by combining multiple components.

[0035] In the roller holding regions 45a and 46a, multiple pockets 44a for accommodating each roller 13a are provided at intervals in the longitudinal direction, which is the first direction. In this embodiment, 20 pockets 44a are provided, corresponding to the number of rollers 13a. Specifically, 10 pockets 44a are provided in each of the roller holding regions 45a and 46a. Adjacent pockets 44a are arranged so that the direction in which the rolling surface 41a of the accommodating roller 13a is exposed is perpendicular to that of adjacent pockets 44a. That is, the pockets 44a are formed such that the direction in which the window portion for inserting the roller 13a opens alternately perpendicular to that of adjacent pockets 44a.

[0036] Figure 16 is a schematic plan view showing an enlarged view of the pinion holding region 48a. Referring to Figure 16, the pinion holding region 48a is provided with a pinion housing portion 81a for housing the pinion 15a. The pinion housing portion 81a is a through hole that penetrates in the Z direction. The pinion housing portion 81a is a region surrounded by a housing wall surface 82a. The housing wall surface 82a is rectangular in shape, with its length in the longitudinal direction (first direction, Y direction) being longer than its length in the transverse direction (X direction) when viewed in the Z direction. The housing wall surface 82a is shaped to conform to the outer shape of the pinion 15a when viewed in the Z direction. The housing wall surface 82a includes a first wall surface 83a located on one side in the thickness direction (X direction) of the pinion 15a placed within the pinion housing portion 81a, and a second wall surface 84a located on the other side in the thickness direction of the pinion 15a placed within the pinion housing portion 81a. The first wall surface 83a and the second wall surface 84a face each other in the X direction. Both the first wall surface 83a and the second wall surface 84a are planes. The housing wall surface 82a also includes a third wall surface 85a located on one side in the direction perpendicular to the thickness direction of the pinion 15a (Y direction), and a fourth wall surface 86a located on the other side in the direction perpendicular to the thickness direction of the pinion 15a (Y direction). The third wall surface 85a and the fourth wall surface 86a face each other in the Y direction. Both the third wall surface 85a and the fourth wall surface 86a are planes. In other words, the housing wall surface 82a is composed of four planes: the first wall surface 83a, the second wall surface 84a, the third wall surface 85a, and the fourth wall surface 86a.

[0037] Figure 17 is a schematic perspective view showing an enlarged portion of the housing wall surface 82a. Figure 17 also shows an enlarged portion of the first wall surface 83a. Figure 18 is a schematic cross-sectional view showing an enlarged portion of the pinion holding region 48a. Figure 18 is a schematic cross-sectional view taken along the cross section indicated by XVIII-XVIII in Figure 16. Referring together to Figures 17 and 18, the pinion holding region 48a is provided with a pair of first notches 75a and 76a that are recessed in the thickness direction of the pinion 15a placed in the pinion housing portion 81a, reducing the thickness from the outer circumference. The first notches 75a and 76a are each recessed in a rectangular shape when viewed in the Z direction. The length of the pinion holding region 48a in the X direction is shorter than the length of the roller holding regions 45a and 46a in the X direction. The pinion holding region 48a is provided with a pair of second notches 77a and 78a, which are cut out on a surface perpendicular to the thickness direction of the pinion 15a located within the pinion housing 81a, and which are inclined from the outer circumference to the outer edge of the pinion housing 81a. The second notches 77a and 78a are located opposite each other in the Y direction.

[0038] Support protrusions 91a and 92a are provided on the housing wall 82a. Each of the support protrusions 91a and 92a protrudes toward the pinion 15a so as to rotatably support the pinion 15a which is placed in the pinion housing 81a. Support protrusion 91a is provided on the first wall 83a, and support protrusion 92a is provided on the second wall 84a. That is, support protrusions 91a and 92a are provided on both the first wall 83a and the second wall 84a. Each of the support protrusions 91a and 92a is provided so as to face each other in the X direction. The positions in the Z direction and the Y direction where the support protrusions 91a and 92a are provided are the same. The tips of the support protrusions 91a and 92a are not in contact, and the support protrusions 91a and 92a are spaced apart in the X direction. That is, the tips of the support protrusions 91a and 92a are separated from each other. The support protrusions 91a and 92a are each solid cylindrical in shape. Specifically, the support protrusions 91a and 92a are each fitted into support recesses 72a provided on the pinion 15a.

[0039] Each of the support protrusions 91a and 92a includes chamfered portions 93a, 94a, 95a, and 96a, respectively. The chamfered portions 93a, 94a, 95a, and 96a are provided such that, when viewed in the thickness direction of the pinion 15a arranged in the pinion housing portion 81a, the amount of protrusion at the center of each support protrusion 91a and 92a is greater than the amount of protrusion at the periphery of each support protrusion 91a and 92a. The chamfered portions 93a and 94a are provided on the support protrusion 91a at intervals in the Z direction. The chamfered portions 95a and 96a are provided on the support protrusion 92a at intervals in the Z direction. Each of the chamfered portions 93a, 94a, 95a, and 96a is tapered.

[0040] Next, the case of housing the pinion 15a in the pinion housing 81a will be described. Figure 19 is a schematic perspective view of housing the pinion 15a in the pinion housing 81a. Referring to Figure 19 as well, when housing the pinion 15a in the pinion housing 81a, the pinion 15a is housed in the pinion housing 81a by moving it in the direction shown in Figure F. In this case, the support protrusions 91a and 92a are fitted into the support recess 72a. At this time, since the support protrusions 91a and 92a are provided with chamfered portions 93a, 94a, 95a, and 96a, the pinion 15a can be smoothly housed in the pinion housing 81a using the chamfered portions 93a, 94a, 95a, and 96a as guides. Furthermore, in this case, the pinion holding region 48a will undergo elastic deformation, but since the pinion holding region 48a is provided with first notches 75a and 76a, the force required for elastic deformation can be reduced. In addition, since the pinion holding region 48a is provided with second notches 77a and 78a, it facilitates elastic deformation and guides the pinion 15a, allowing the pinion 15a to be smoothly housed in the pinion housing 81a. Moreover, since the support protrusions 91a and 92a are provided with chamfered portions 94a and 96a, respectively, the pinion 15a can also be smoothly housed in the pinion housing 81a by inserting it from below in the direction indicated by arrow Z.

[0041] The linear motion guide unit 10a can prevent misalignment of the retainer 14a that holds the roller 13a by utilizing the pinion 15a, the first rack 16a, and the second rack 17a. Therefore, it can properly guide linear motion. The external teeth 73a of the pinion 15a are positioned between the first track base 11a and the second track base 12a, and the first rack 16a and the second rack 17a are attached to the outer surfaces of the first track base 11a and the second track base 12a, respectively. This configuration allows the pinion 15a to be positioned vertically. As a result, the external teeth 73a of the pinion 15a can be oriented to face the outside of the track base, and the racks can be placed outside the track base. This allows the diameter of the roller 13a to be increased compared to when the racks are placed inside the track base, thereby increasing the load capacity. Furthermore, the retainer 14a includes roller retaining regions 45a, 46a for holding the roller 13a, and a pinion retaining region 48a provided with a pinion housing 81a for housing the pinion 15a. The housing wall surface 82a surrounding the pinion housing 81a is provided with support protrusions 91a, 92a that project toward the pinion 15a side within the pinion housing 81a and fit into a support recess 72a, in order to rotatably support the pinion 15a housed within the pinion housing 81a. As a result, there is no need to provide new parts to realize the mechanism for holding the pinion 15a. In addition, the structure for rotatably supporting the pinion 15a can be simplified, and molding can be done without forced removal, thus making the molding of the retainer 14a easier. Therefore, the linear motion guide unit 10a described above can improve productivity while reducing the number of parts.

[0042] In this embodiment, the support protrusions 91a and 92a are cylindrical. The support recess 72a is recessed in the shape of a round hole. Therefore, it is easy to rotatably support the pinion 15a. Consequently, the second track base 12a can be moved in a straight line more smoothly.

[0043] In this embodiment, the support recess 72a is a through hole that penetrates the pinion 15a in the thickness direction. Therefore, the support recess 72a can be easily formed, and the support protrusions 91a and 92a can be securely fitted into the support recess 72a. Thus, the pinion 15a can be more easily supported in a rotatable manner.

[0044] In this embodiment, the pinion 15a is provided in the outer peripheral region of the support recess 72a, and includes a thick-walled portion 74a in which the pinion 15a is thicker than other regions. Therefore, the rigidity of the pinion 15a, particularly the rigidity around the support recess 72a, can be increased. Consequently, the risk of damage to the pinion 15a is reduced, and the second track base 12a can be moved linearly stably over a long period of time.

[0045] In this embodiment, the support protrusions 91a and 92a include chamfered portions 93a, 94a, 95a, and 96a, which are provided such that, when viewed in the thickness direction of the pinion 15a arranged in the pinion housing portion 81a, the amount of protrusion at the center of the support protrusions 91a and 92a is greater than the amount of protrusion at the periphery of the support protrusions 91a and 92a. Therefore, the chamfered portions 93a, 94a, 95a, and 96a can be used to make it easier to fit the support protrusions 91a and 92a into the support recess 72a. Thus, assembly can be improved.

[0046] In this embodiment, the roller holding regions 45a and 46a and the pinion holding region 48a are integrally constructed. Therefore, the number of parts can be reduced, and assembly can be improved.

[0047] In this embodiment, the retainer 14a is made of resin. Therefore, by effectively utilizing the elastic deformation of the retainer 14a, the support protrusions 91a and 92a can be easily fitted into the support recess 72a. Furthermore, the pinion 15a can be mass-produced by molding using a mold. Thus, productivity can be improved.

[0048] In this embodiment, the support protrusions 91a and 92a are provided on both the first wall surface 83a and the second wall surface 84a. Therefore, the pinion 15a can be supported by utilizing the support protrusions 91a and 92a extending from both the first wall surface 83a and the second wall surface 84a. Consequently, the pinion 15a can be rotated more stably, and the second raceway 12a can be made to move smoothly in a linear motion.

[0049] In this embodiment, the pinion holding region 48a is provided with first notches 75a and 76a that are recessed in the thickness direction of the pinion 15a, which is placed in the pinion housing 81a, so as to reduce the thickness from the outer circumference. Therefore, the first notches 75a and 76a make the pinion holding region 48a more elastically deformable, making it easier to fit the support protrusions 91a and 92a into the support recesses 72a when housing the pinion 15a in the pinion housing 81a. Thus, the ease of assembly can be further improved.

[0050] In this embodiment, the pinion holding region 48a is provided with second notches 77a and 78a cut out on a surface perpendicular to the thickness direction of the pinion 15a, which is positioned within the pinion housing 81a, so as to be inclined from the outer circumference to the outer edge of the pinion housing 81a. Therefore, when housing the pinion 15a in the pinion housing 81a, the second notches 77a and 78a can be used as guides, and the second notches 77a and 78a make the pinion holding region 48a more elastically deformable, making it easier to fit the support protrusions 91a and 92a into the support recesses 72a. Thus, assembly ease can be further improved.

[0051] (Other embodiments) In the above embodiment, the support recess is a through hole that penetrates in the thickness direction of the pinion, but it is not limited to this, and the support recess may not penetrate in the thickness direction of the pinion and may have a recessed shape. Also, the support projection is a solid cylindrical shape, but it is not limited to this, and the support projection may be a hollow cylindrical shape. Furthermore, the support projection may be a polygonal cylindrical shape. In addition, the support projection may be provided on at least one of the first wall surface and the second wall surface.

[0052] Furthermore, in the above embodiment, the pinion holding region is provided with a first notch and a second notch, but it is not limited to this, and at least one of the first notch and the second notch, or both, may not be provided.

[0053] In the above embodiment, a thickened portion is provided on the pinion, but this is not limited to this, and the pinion does not need to have a thickened portion. Also, in the above embodiment, the roller holding region and the pinion holding region are formed as a single unit, but this is not limited to this, and the roller holding region and the pinion holding region may be formed as separate units.

[0054] Furthermore, in the above embodiment, the support projection may be provided so as to extend from at least one of the first wall surface and the second wall surface. By doing so, the support projection can be provided so as to extend from at least one of the opposing first wall surface and the second wall surface. Therefore, when housing the pinion in the pinion housing, the support projection can be easily fitted into the support recess. Thus, assembly can be further improved.

[0055] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the invention is defined by the claims and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of symbols]

[0056] 10a Linear guide unit, 11a First track base, 12a Second track base, 13a Roller, 14a Retainer, 15a Pinion, 16a First rack, 17a Second rack, 21a, 31a First track surface, 22a, 32a Second track surface, 23a, 33a Relief section, 24a, 28a, 29a, 34a, 38a, 39a Surface, 27a, 37a, 53a, 63a Through hole, 41a Rolling surface, 42a End face, 44a Pocket, 45a, 46a Roller holding area, 48a Pinion holding area, 51a, 61a Plate-shaped section, 52a First rack teeth, 54a, 64a Bolt, 55a, 65a Notch, 56a, 66a Side end, 62a Second rack teeth, 71a disc portion, 72a support recess, 73a external teeth, 74a thick portion, 75a, 76a first notch, 77a, 78a second notch, 81a pinion housing portion, 82a housing wall surface, 83a first wall surface, 84a second wall surface, 85a third wall surface, 86a fourth wall surface, 91a, 92a support projection, 93a, 94a, 95a, 96a chamfered portion.

Claims

1. A linear motion guide unit comprising a first track bed extending in a first direction which is the longitudinal direction, and a second track bed extending in the first direction and positioned opposite to the first track bed in a second direction which is perpendicular to the first direction, wherein the second track bed performs linear motion relative to the first track bed in the first direction, A plurality of rollers are arranged alternately at intervals in the first direction such that their rolling axes are perpendicular to each other, A holder is provided between the first and second track beds in the second direction, with multiple pockets for housing each of the rollers spaced apart in the first direction, and the holder is provided for holding the multiple rollers, A pinion is provided with multiple external teeth on its outer circumference, positioned between the first and second raceway in the second direction, and rotatably supported. A first rack is attached to the outer circumferential surface of the first track bed and is provided with a plurality of first rack teeth that mesh with the external teeth, The second rack is attached to the outer circumferential surface of the second raceway and is provided with a plurality of second rack teeth that mesh with the external teeth, The aforementioned retainer is, A roller holding region is provided in which the pocket for holding the roller is located, The system includes the roller holding region and a pinion holding region, which is arranged adjacent to the roller holding region in the first direction and includes a pinion housing portion for housing the pinion such that the external teeth mesh with the second rack teeth, The roller holding region and the pinion holding region are formed as a single unit. The aforementioned pinion is, A disc portion having a support recess that is concave in the thickness direction, The disc portion includes a plurality of external teeth arranged at intervals in the circumferential direction on its outer surface, The pinion housing is surrounded by a housing wall, The aforementioned housing wall surface is provided with support projections that protrude toward the pinion and fit into the support recess, so as to rotatably support the pinion disposed within the pinion housing portion. A linear motion guide unit, wherein the pinion holding region is provided with a first notch that is recessed in the thickness direction of the pinion, which is arranged within the pinion housing, so as to reduce the thickness from the outer circumference.

2. The aforementioned support projection is cylindrical, The linear motion guide unit according to claim 1, wherein the support recess is recessed in the shape of a circular hole.

3. The linear motion guide unit according to claim 1 or claim 2, wherein the support recess is a through hole that penetrates in the thickness direction of the pinion.

4. The linear motion guide unit according to claim 1 or 2, wherein the pinion is provided in the outer peripheral region of the support recess and includes a thick-walled portion in which the thickness of the pinion is greater than that of other regions.

5. The linear motion guide unit according to claim 1 or 2, wherein the support projection includes a chamfered portion provided such that, when viewed in the thickness direction of the pinion disposed within the pinion housing, the amount of protrusion at the center of the support projection is greater than the amount of protrusion at the periphery of the support projection.

6. The linear motion guide unit according to claim 1 or claim 2, wherein the retainer is made of resin.

7. The aforementioned housing wall surface is A first wall surface located on one side in the thickness direction of the pinion, which is arranged within the pinion housing, It includes a second wall surface located on the other side in the thickness direction of the pinion disposed within the pinion housing and facing the first wall surface, The linear motion guide unit according to claim 1 or claim 2, wherein the support projection is provided so as to extend from at least one of the first wall surface and the second wall surface.

8. The linear motion guide unit according to claim 7, wherein the support projection is provided on both the first wall surface and the second wall surface.

9. The linear motion guide unit according to claim 1 or 2, wherein the pinion holding region is provided with a second notch cut out on a plane perpendicular to the thickness direction of the pinion disposed within the pinion housing, such that it slopes from the outer circumference to the outer edge of the pinion housing.

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