Linear guide unit

Abstract

This linear motion guide unit comprises a first track member and a second track member. The second track member performs linear motion relative to the first track member in a first direction. The linear motion guide unit includes: a plurality of rollers; a cage that holds the plurality of rollers; a pinion; a first rack; and a second rack. The cage includes: a roller holding region that holds the plurality of rollers; and a pinion holding region that is disposed adjacent to the roller holding region in the first direction, and has a pinion accommodating portion that accommodates the pinion such that external teeth mesh with second rack teeth. The roller holding region and the pinion holding region are integrally formed. The linear motion guide unit includes a pinion cover that is attached to the pinion holding region such that the pinion is interposed between the pinion cover and the pinion holding region, and the external teeth mesh with first rack teeth.

Description

[Technical Field]

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

[0002] A linear motion guide device is known that includes a pinion and a rack that guide a cage that holds rolling elements (see, for example, Patent Document 1). Such a linear motion guide device can appropriately guide the cage with a rack-and-pinion structure, thereby reducing the risk of the cage becoming misaligned. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-327742 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the linear motion guide device disclosed in Patent Document 1, the pinion holder that holds the pinion is configured as two separate parts, and the pinion is held by sandwiching it between the two independent parts. This pinion holder is then reattached to the cage. During attachment, a convex portion formed on the pinion holder is fitted into a dovetail groove formed on the cage. However, with this configuration, especially when miniaturization is attempted, the width of the convex portion becomes extremely narrow, increasing the risk of the convex portion breaking during manufacturing or assembly. Furthermore, the width of the dovetail groove also becomes small, making assembly difficult. As a result, it becomes difficult to improve productivity.

[0005] Therefore, one of the objects is to provide a linear motion guide unit that can improve productivity. [Means for solving the problem]

[0006] A linear guide unit according to the present disclosure includes a first track member extending in a first direction, which is the longitudinal direction, and a second track member extending in the first direction and arranged opposite the first track member in a second direction, which is a direction perpendicular to the first direction, wherein the second track member performs linear motion relative to the first track member in the first direction. The linear guide unit includes: a plurality of rollers arranged alternately at intervals in the first direction so that their rolling axes are perpendicular to each other; a cage arranged between the first track member and the second track member in the second direction, which holds the plurality of rollers and has a plurality of pockets spaced apart in the first direction for accommodating each roller; a pinion arranged between the first track member and the second track member in the second direction and rotatably supported, which has a plurality of external teeth on its outer periphery; a first rack attached to the outer peripheral surface of the first track member and provided with a plurality of first rack teeth that mesh with the external teeth; and a second rack attached to the outer peripheral surface of the second track member and provided with a plurality of second rack teeth that mesh with the external teeth. The cage includes a roller holding area that holds multiple rollers, and a pinion holding area that is arranged adjacent to the roller holding area in the first direction and has a pinion accommodating portion that accommodates a pinion so that the external teeth of the pinion mesh with the second rack teeth. The roller holding area and the pinion holding area are integrally configured. The linear motion guide unit includes a pinion cover that is attached to the pinion holding area so that the pinion is sandwiched between the pinion holding area and the pinion cover and the external teeth mesh with the first rack teeth. [Effects of the Invention]

[0007] According to the linear motion guide unit described above, productivity can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a linear motion guide unit according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic plan view of the linear motion guide unit shown in FIG. [Figure 3] FIG. 3 is a schematic side view of the linear motion guide unit shown in FIG. [Figure 4]FIG. 4 is a schematic front view of the linear motion guide unit shown in FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view taken along the line VV in FIG. [Figure 6] FIG. 6 is a schematic perspective view of linear motion guide unit 10a with a second raceway member, which will be described later, removed. [Figure 7] FIG. 7 is a schematic perspective view showing an enlarged portion of the cage. [Figure 8] FIG. 8 is a schematic cross-sectional view of a portion of the cage shown in FIG. [Figure 9] FIG. 9 is a view of a part of the cage shown in FIG. 7, seen from the window side of the pocket. [Figure 10] FIG. 10 is a schematic perspective view showing a process for manufacturing a part of the cage. [Figure 11] FIG. 11 is a schematic perspective view showing the appearance of the first rack. [Figure 12] FIG. 12 is a schematic perspective view showing an enlarged portion of the first rack shown in FIG. [Figure 13] FIG. 13 is an exploded perspective view of the linear motion guide unit, showing an enlarged view of a part of the cage. [Figure 14] FIG. 14 is a schematic plan view of the pinion cover. [Figure 15] FIG. 15 is a schematic side view of the pinion cover. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Outline of the embodiment] The linear guide unit of the present disclosure includes a first track member extending in a first direction, which is the longitudinal direction, and a second track member extending in the first direction and arranged opposite the first track member in a second direction, which is a direction perpendicular to the first direction, wherein the second track member performs linear motion relative to the first track member in the first direction. The linear guide unit includes: a plurality of rollers arranged alternately at intervals in the first direction so that their rolling axes are perpendicular to each other; a cage arranged between the first track member and the second track member in the second direction, with a plurality of pockets for accommodating each roller spaced apart in the first direction, to hold the plurality of rollers; a pinion with a plurality of external teeth on its outer periphery, arranged between the first track member and the second track member in the second direction and rotatably supported; a first rack attached to the outer peripheral surface of the first track member and provided with a plurality of first rack teeth that mesh with the external teeth; and a second rack attached to the outer peripheral surface of the second track member and provided with a plurality of second rack teeth that mesh with the external teeth. The cage includes a roller holding area that holds multiple rollers, and a pinion holding area that is arranged adjacent to the roller holding area in the first direction and has a pinion accommodating portion that accommodates a pinion so that the external teeth of the pinion mesh with the second rack teeth. The roller holding area and the pinion holding area are integrally configured. The linear motion guide unit includes a pinion cover that is attached to the pinion holding area so that the pinion is sandwiched between the pinion holding area and the pinion cover and the external teeth mesh with the first rack teeth.

[0010] A linear guide unit in which the second raceway member moves linearly relative to the first raceway member requires a mechanism for smooth linear motion. The linear guide unit uses a pinion, a first rack, and a second rack to prevent misalignment of the cage that holds the rollers. This allows for proper linear motion guidance. The pinion's external teeth are positioned between the first raceway member and the second raceway member, and the first rack and second rack are attached to the outer circumferential surfaces of the first raceway member and the second raceway member, respectively, allowing the pinion to be vertically mounted. This increases the contact length between the raceway surface of the raceway member and the rollers, thereby increasing the load capacity.

[0011] According to the linear guide unit of the present disclosure, the cage includes a roller holding area for holding rollers and a pinion holding area in which a pinion accommodating portion is provided. The roller holding area and the pinion holding area are integrally configured. This eliminates the need to form protrusions or dovetail grooves when incorporating a pinion-holding mechanism into the cage. This eliminates the need for work such as damaging the protrusions or fitting them into the dovetail grooves, improving productivity. This is particularly true when manufacturing small linear guide units, such as those with rollers with diameters of less than 4 mm. Furthermore, because the pinion is held in the cage by being sandwiched between the pinion covers, the risk of the pinion becoming dislodged or falling off the cage is significantly reduced. Therefore, this linear guide unit improves productivity.

[0012] In the linear guide unit described above, the pinion holding area may be provided at the center in the first direction. A pair of roller holding areas may be provided at both ends of the pinion holding area in the first direction. By doing so, the pinion holding area is provided at the center in the longitudinal direction, i.e., the first direction, and the cage can be guided in a balanced manner in the longitudinal direction. Furthermore, the first raceway member and the second raceway member can appropriately bear loads without causing any deviation in the portions where the roller holding areas are provided in the longitudinal direction.

[0013] In the linear guide unit described above, the pinion cover may be attached to the pinion holding area by snap fitting. This allows the pinion cover to be attached by sandwiching the pinion, utilizing the elastic deformation of the material. This simplifies assembly and improves productivity.

[0014] In the linear motion guide unit, at least one of the first rack and the second rack may be plate-shaped. This simplifies the shape of at least one of the first rack and the second rack, thereby improving productivity.

[0015] In the linear motion guide unit described above, at least one of the first rack teeth and the second rack teeth may be provided so as to protrude in the second direction. This makes it easy to mesh at least one of the first rack teeth provided on the first rack or the second rack teeth provided on the second rack with the external teeth of the pinion in the second direction. Therefore, it is possible to guide the cage by appropriately meshing the external teeth of the pinion with the rack teeth while achieving a compact size and a simplified shape.

[0016] In the linear guide unit described above, the cage may include a pair of side stays, a plurality of pillars spaced apart in a first direction and connecting the pair of side stays to form a pocket, and a retaining claw that, when viewed from the side where the window of the pocket is open, is connected to the side wall surface of one of the pair of side stays and the side wall surface of the pillar and protrudes toward the window, preventing the roller from falling out of the pocket. This makes it easier to distribute the force pushing against the retaining claw in the first and second directions when the roller is inserted into the pocket over the retaining claw that prevents the roller from falling out of the pocket. This reduces the mechanical load on the retaining claw when the roller is inserted, reducing the risk of damage to the retaining claw.

[0017] In the linear guide unit, a pair of retaining claws may be provided, one on one side stay and the other on the other side stay, which can further reduce the mechanical load on each retaining claw and further reduce the risk of damage to the retaining claws.

[0018] In the linear motion guide unit, the retaining claw may include a flat surface that is continuous with the side wall surface of one of the pair of side stays and the side wall surface of the pillar portion. This allows the shape of the retaining claw to be relatively simple, and the area that catches the roller to be relatively large, greatly reducing the risk of the roller falling out of the pocket.

[0019] In the linear motion guide unit, the shape of the retaining claws may be an isosceles triangle, with equal sides at the portions that connect to the side wall surfaces of the side stays and the posts, when viewed from the side where the pocket window opens. This makes it easier to distribute the load capacity equally between the side stays and the posts when installing the rollers in the pockets. This improves installation ease and productivity.

[0020] In the linear motion guide unit, the first raceway member may have the same shape as the second raceway member, which allows the respective parts to be shared and improves productivity.

[0021] The linear guide unit of the present disclosure includes a first track member extending in a first direction, which is the longitudinal direction, and a second track member extending in the first direction and arranged opposite the first track member in a second direction, which is a direction perpendicular to the first direction, wherein the second track member performs linear motion relative to the first track member in the first direction. The linear guide unit includes: a plurality of rollers arranged alternately at intervals in the first direction so that their rolling axes are perpendicular to each other; a cage arranged between the first track member and the second track member in the second direction, with a plurality of pockets for accommodating each roller spaced apart in the first direction, to hold the plurality of rollers; a pinion with a plurality of external teeth on its outer periphery, arranged between the first track member and the second track member in the second direction and rotatably supported; a first rack attached to the outer peripheral surface of the first track member and provided with a plurality of first rack teeth that mesh with the external teeth; and a second rack attached to the outer peripheral surface of the second track member and provided with a plurality of second rack teeth that mesh with the external teeth. The retainer includes a pair of side stays, a plurality of pillars spaced apart in a first direction and connecting the pair of side stays to form a pocket, and a retaining claw that, when viewed from the side where the window portion of the pocket opens, is connected to the side wall surface of one of the pair of side stays and the side wall surface of the pillars and protrudes toward the window portion, preventing the roller from falling out of the pocket.

[0022] With this linear motion guide unit, when the roller is placed in the pocket over the retaining pawl that prevents the roller from falling out, the force pushing against the retaining pawl can be easily dispersed in the first direction and in a direction perpendicular thereto, thereby reducing the mechanical load on the retaining pawl when the roller is placed in the pocket and reducing the risk of damage to the retaining pawl.

[0023] [Specific example of embodiment] Next, an example of a specific embodiment of the linear guide unit of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0024] (Embodiment 1) First, a first embodiment of the present disclosure will be described. FIG. 1 is a schematic perspective view of a linear guide unit according to the first embodiment of the present disclosure. FIG. 2 is a schematic plan view of the linear guide unit shown in FIG. 1. FIG. 2 is a view seen in the direction of arrow II shown in FIG. 1. FIG. 3 is a schematic side view of the linear guide unit shown in FIG. 1. FIG. 3 is a view seen in the direction of arrow III shown in FIG. 1. FIG. 4 is a schematic front view of the linear guide unit shown in FIG. 1. FIG. 4 is a view seen in the direction of arrow IV shown in FIG. 1. FIG. 5 is a schematic cross-sectional view taken along the line VV in FIG. 2. FIG. 6 is a schematic perspective view of a linear guide unit 10a with a second track member, described later, removed. In the figures shown in FIG. 1 and subsequent figures, the direction indicated by arrow Y is the longitudinal direction, the direction indicated by arrow X is the lateral direction, and the direction indicated by arrow Z is the thickness direction.

[0025] 1, 2, 3, 4, 5, and 6, linear motion guide unit 10a in embodiment 1 includes first track member 11a, second track member 12a, multiple rollers 13a, a cage 14a, a pinion 15a, a first rack 16a, and a second rack 17a. First track member 11a and second track member 12a each have a shape extending in a first direction (Y direction), which is the longitudinal direction. First track member 11a and second track member 12a have the same shape. That is, the lengths of first track member 11a in the X, Y, and Z directions are equal to the lengths of second track member 12a in the X, Y, and Z directions, respectively. Second track member 12a corresponds to a member obtained by inverting first track member 11a in the Z and X directions.

[0026] The second track member 12a is disposed opposite the first track member 11a in a second direction (X direction) that is perpendicular to the first direction. The linear motion guide unit 10a is a linear motion guide unit in which the second track member 12a performs linear motion relative to the first track member 11a in the first direction.

[0027] The first raceway member 11a includes a first raceway surface 21a and a second raceway surface 22a on which the rollers 13a roll. The first raceway surface 21a and the second raceway surface 22a are each formed of a flat surface extending in the longitudinal direction. The first raceway surface 21a is inclined at 45 degrees with respect to the XY plane and the YZ plane (see particularly FIGS. 3 and 5). The second raceway surface 22a is also inclined at 45 degrees with respect to the XY plane and the YZ plane. The second raceway surface 22a is inclined at 90 degrees with respect to the first raceway surface 21a. A groove-shaped relief portion 23a extending in the Y direction is provided between the first raceway surface 21a and the second raceway surface 22a.

[0028] One surface 24a in the X direction of the first track member 11a, on which the first track surface 21a and the second track surface 22a are provided, is parallel to the YZ plane and is disposed so as to face a surface 34a of the second track member 12a (described later). Round recesses 26a are provided on both longitudinal end surfaces 25a of the first track member 11a. The first track member 11a is provided with a plurality of round through holes 27a that penetrate the thickness direction (Z direction) at intervals along the longitudinal direction. In this embodiment, a total of seven through holes 27a are provided. The first track member 11a is provided with a plurality of recesses 29a that are recessed in the thickness direction from one surface 28a in the thickness direction, around the area where each through hole 27a is provided in the thickness direction (Z direction). In this embodiment, a total of seven recesses 29a are also provided. Each recess 29a includes a semicircular wall surface as viewed in the thickness direction, and is configured to extend to the other surface 30a in the X direction. The first track member 11a is provided with a plurality of mounting holes recessed from the surface 28a in the thickness direction and used to mount the first rack 16a. In this embodiment, a total of four mounting holes are provided at intervals in the longitudinal direction. The mounting holes are provided at positions that avoid the recessed portion 29a.

[0029] The second track member 12a has a similar configuration to the first track member 11a. This allows for the sharing of components, improving productivity. Specifically, the second track member 12a includes a first track surface 31a and a second track surface 32a on which the rollers 13a roll. The second track member 12a also has a recess 33a with a similar configuration to the recess 23a. One surface 34a in the X direction of the second track member 12a, on which the first track surface 31a and the second track surface 32a are provided, is parallel to the YZ plane and faces the surface 24a. The second track member 12a also has circular recesses 36a on both longitudinal end surfaces 35a. The second track member 12a has a total of seven circular through-holes 37a spaced apart along its length and penetrating through its thickness. The second track member 12a is provided with a total of seven recesses 39a recessed in the thickness direction from one surface 38a in the thickness direction around the area where each through hole 37a is provided in the thickness direction. The recesses 39a include a semicircular wall surface in the thickness direction and are configured to extend to the other surface 40a in the X direction.

[0030] Next, the configuration of the rollers 13a and the cage 14a will be described. The rollers 13a are solid cylindrical. The rollers 13a include 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 rollers 13a. All of the rollers 13a have the same shape. The rollers 13a are alternately arranged at intervals in the longitudinal direction, which is the first direction, so that the rolling axes are perpendicular to each other. In this embodiment, the linear motion guide unit 10a includes 22 rollers 13a.

[0031] The retainer 14a has a shape that extends in the longitudinal direction, which is the first direction. The retainer 14a holds the plurality of rollers 13a so that they can roll. The retainer 14a is made of resin. The retainer 14a is disposed between the first raceway member 11a and the second raceway member 12a in the lateral direction (X direction), which is the second direction.

[0032] FIG. 7 is a schematic perspective view showing an enlarged portion of the cage 14a. FIG. 8 is a schematic cross-sectional view of a portion of the cage 14a shown in FIG. 7. FIG. 8 is a cross-sectional view of a portion of the cage shown in FIG. 7, taken along a plane that includes the center of one roller 13a in the rolling axis direction and is perpendicular to the rolling axis direction of the roller 13a. FIG. 9 is a view of a portion of the cage 14a shown in FIG. 7, seen from the window portion 45a side of the pocket 44a. FIG. 9 is a view from a direction in which the rolling surface 41a of the roller 13a housed in the pocket 44a is exposed. FIG. 9 is also a view from a direction perpendicular to the rolling axis direction of the roller 13a housed in the pocket 44a. In FIG. 9, the outer shape of the roller 13a housed in the pocket 44a is shown by a dashed line to facilitate understanding.

[0033] 7, 8, and 9, the cage 14a is provided with a plurality of pockets 44a that accommodate the rollers 13a, spaced apart in the longitudinal direction, which is the first direction. In this embodiment, 22 pockets 44a are provided, corresponding to the number of rollers 13a. Adjacent pockets 44a are provided so that the directions in which the rolling surfaces 41a of the accommodated rollers 13a are exposed are perpendicular to each other. In other words, the pockets 44a are formed so that the opening directions of the windows 45a, through which the rollers 13a are inserted, are alternately perpendicular to each other in adjacent pockets 44a.

[0034] The cage 14a includes a pair of side stays 51a, 52a and multiple pillars 53a connecting the pair of side stays 51a, 52a to form a pocket 44a. Each of the side stays 51a, 52a is flat and has a through hole 54a in its center. This through hole 54a is used for the flow of lubricant and for removing sink marks in the resin during molding. The side stays 51a, 52a are arranged in positions inclined 90 degrees in adjacent pockets 44a. The multiple pillars 53a are arranged at intervals in the longitudinal direction (Y direction), which is the first direction.

[0035] Here, the cage 14a includes retaining claws 55a and 56a that prevent the roller 13a from falling out of the pocket 44a. A pair of retaining claws 55a and 56a are provided on one side stay 51a and the other side stay 52a, respectively. When viewed from the side where one window portion 45a of the pocket 44a opens (see FIG. 9 in particular), the retaining claw 55a connects with a side wall surface 57a of the side stay 51a and a side wall surface 59a of the pillar portion 53a and protrudes toward the window portion 45a. When viewed from the side where one window portion 45a of the pocket 44a opens, the retaining claw 56a connects with a side wall surface 58a of the side stay 52a and a side wall surface 59a of the pillar portion 53a and protrudes toward the window portion 45a. When viewed from the side where one window portion 45a of the pocket 44a opens, the retaining claws 55a and 56a are each tapered. The retaining claws 55a, 56a each include flat surfaces 61a, 62a that connect to the side wall surfaces 57a, 58a of the pair of side stays 51a, 52a and the pillar portion 53a. When viewed from the side where one window portion 45a of the pocket 44a opens, the shape of the retaining claws 55a, 56a is an isosceles triangle with equilateral sides at the portions that connect to the side wall surfaces 57a, 58a of the side stays 51a, 52a and the portions that connect to the side wall surface 59a of the pillar portion 53a. The portions of the retaining claws 55a that correspond to the equilateral sides of the isosceles triangle are shown by dashed lines in FIG. 9. On the side where one window portion 45a of the pocket 44a opens, no retaining claw is provided on the opposing pillar portion 53a side in the longitudinal direction. On the side where the other window portion 46a of the pocket 44a opens, retaining claws 63a, 64a are formed that protrude toward the window portion 46a and are connected to the side wall surface 59a of the pillar portion 53a facing the pillar portion 53a on which the retaining claws 55a, 56a are provided, and to the respective side wall surfaces 57a, 58a of the pair of side stays 51a, 52a.

[0036] The retention claws 55a, 56a are manufactured, for example, as follows. FIG. 10 is a schematic perspective view showing a process for manufacturing a portion of the retainer 14a. Referring also to FIG. 10, when molding the retention claws 55a, 56a, a jig 67a is prepared having recessed flat surfaces 65a, 66a shaped to conform to the flat surfaces 61a, 62a that constitute the retention claws 55a, 56a. This jig 67a is placed in the pocket 44a, and resin is poured into it to perform molding. As a result, the retention claws 55a, 56a, each composed of the flat surfaces 61a, 62a, are formed in portions facing the flat surfaces 65a, 66a. In this case, the flat surfaces 65a, 66a on the jig 67a can be formed by chamfering the corners, making manufacturing relatively easy. Furthermore, because the configuration allows resin to flow easily, the retention claws 55a, 56a can be reliably formed in the above shape even when the size is small.

[0037] Next, the configurations of the pinion 15a and the first rack 16a will be described. With particular reference to Figures 5 and 6, the pinion 15a has a plurality of external teeth 71a provided on its outer periphery. The pinion 15a includes rotation shafts 72a and 73a. The pinion 15a is held by a cage 14a and supported rotatably about the rotation shafts 72a and 73a.

[0038] Fig. 11 is a schematic perspective view showing the appearance of the first rack 16a. Fig. 12 is a schematic perspective view showing an enlarged portion of the first rack 16a shown in Fig. 11. Referring to Figs. 11 and 12 together, the first rack 16a is plate-shaped, specifically, flat. The first rack 16a is formed, for example, by punching a single steel plate along the outer shape of the first rack 16a and providing through holes and first rack teeth.

[0039] The first rack 16a has multiple through holes 74a (four in this embodiment) spaced apart along the longitudinal direction and penetrating in the thickness direction, i.e., the Z direction. The first rack 16a is attached to the outer peripheral surface of the first track member 11a (the surface 28a of the first track member 11a in this embodiment) with bolts 76a using the through holes 74a. The first rack 16a has multiple notches 75a (three in this embodiment) recessed in the X direction. The three notches 75a are positioned so that the through holes 27a and recesses 29a are exposed when the first rack 16a is attached to the surface 28a of the first track member 11a. By forming these notches 75a, the first track member 11a can be fixed in place using the through holes 27a even after the first rack 16a is attached to the surface 28a of the first track member 11a.

[0040] The first rack 16a is provided with a plurality of first rack teeth 77a that mesh with the external teeth 71a of the pinion 15a. The plurality of first rack teeth 77a are comb-shaped. The plurality of first rack teeth 77a are provided so as to protrude in the X direction, which is the second direction. That is, the first rack teeth 77a are provided so as to protrude in the X direction from the side surface of the first rack 16a in the X direction. The first rack teeth 77a are provided so as to narrow in width on the side that meshes with the external teeth 71a of the pinion 15a in the Z direction. In the longitudinal direction, the groove portion 78a adjacent to the first rack teeth 77a is provided so as to widen in width on the side that meshes with the external teeth 71a of the pinion 15a. The side wall surface that constitutes the first rack teeth 77a is tapered when viewed in the X direction. The first rack teeth 77a having such a shape are formed by, for example, press processing or etching. With such first rack teeth 77a, the thickness of the first rack 16a is equal to the height of the first rack teeth 77a, so the height of the teeth can be reduced. The first rack 16a may be made of resin, but in consideration of strength, it may also be made of metal, such as steel plate.

[0041] The configuration of the second rack 17a is similar to that of the first rack 16a, and therefore a description thereof will be omitted. The second rack 17a includes second rack teeth 79a. The second rack 17a is attached and fixed to the second track member 12a.

[0042] Next, the configuration of the cage 14a will be described again. FIG. 13 is a schematic perspective view showing an enlarged portion of the cage 14a in an exploded perspective view of the linear guide unit 10a. Referring also to FIG. 13, the cage 14a includes roller holding areas 81a and 82a that hold a plurality of rollers 13a, and a pinion holding area 83a that holds the pinion 15a. In this embodiment, a pair of roller holding areas 81a and 82a is provided. The roller holding areas 81a and 82a and the pinion holding area 83a are arranged adjacent to each other in the longitudinal direction, which is the first direction. The pinion holding area 83a is provided in the center in the first direction. The pair of roller holding areas 81a and 82a are provided on both ends of the pinion holding area 83a in the first direction. Eleven pockets 44a are provided in each of the roller holding areas 81a and 82a.

[0043] A pinion accommodating portion 84a is provided in the pinion holding region 83a. The pinion accommodating portion 84a has a groove-like shape recessed from the surface 85a in the Z direction. The pinion accommodating portion 84a also has rotating shaft accommodating portions 86a and 87a that accommodate the rotating shafts 72a and 73a. The pinion accommodating portion 84a penetrates in the Z direction except for the areas where the rotating shaft accommodating portions 86a and 87a are provided. Due to the configuration of the pinion accommodating portion 84a, the external teeth 71a of the accommodated pinion 15a are exposed in the Z direction, and the exposed external teeth 71a of the pinion 15a mesh with the second rack teeth 79a of the second rack 17a.

[0044] The pinion holding area 83a is provided with a pair of fitting grooves 88a, 89a. The fitting grooves 88a, 89a are spaced apart in the longitudinal direction and sandwich the pinion accommodating portion 84a. The fitting grooves 88a, 89a are provided adjacent to the pair of roller holding areas 81a, 82a, respectively.

[0045] Here, the linear motion guide unit 10a includes a pinion cover 91a. FIG. 14 is a schematic plan view of the pinion cover 91a. FIG. 15 is a schematic side view of the pinion cover 91a. Referring to FIGS. 14 and 15 together, the pinion cover 91a is attached to the pinion holding area 83a. The pinion cover 91a is made of, for example, resin and can easily elastically deform. The pinion cover 91a has a shape extending in the longitudinal direction and includes a gap 92a that accommodates a portion of the pinion holding area 83a, an opening 93a that penetrates in the Z direction, and claw-shaped fitting claws 94a and 95a provided on both ends of the pinion cover 91a in the longitudinal direction. The pinion cover 91a is attached to the pinion holding area 83a by elastically deforming the fitting claws 94a and 95a to fit into the fitting grooves 88a and 89a. The fitting claws 94a and 95a are attached to the pinion holding area 83a by snap-fitting. At this time, a portion of the pinion holding area 83a enters the gap 92a, and the pinion 15a is sandwiched between the pinion holding area 83a and the pinion cover 91a. This exposes the external teeth 71a of the pinion 15a from the opening 93a. The exposed external teeth 71a mesh with the first rack teeth 77a of the first rack 16a.

[0046] The linear motion guide unit 10a configured as described above utilizes the pinion 15a, first rack 16a, and second rack 17a to prevent misalignment of the cage 14a that holds the roller 13a. This allows for proper linear motion guidance. The external teeth 71a of the pinion 15a are positioned between the first raceway member 11a and the second raceway member 12a, and the first rack 16a and second rack 17a are attached to the outer peripheral surfaces of the first raceway member 11a and the second raceway member 12a, respectively. This allows the pinion 15a to be vertically oriented. This increases the contact length between the raceway surface of the raceway member and the roller 13a, thereby increasing the load capacity.

[0047] Furthermore, in the linear guide unit 10a, the cage 14a includes roller holding areas 81a and 82a that hold the rollers 13a and a pinion holding area 83a that has a pinion accommodating portion 84a. The roller holding areas 81a and 82a and the pinion holding area 83a are integrally configured. This eliminates the need to form protrusions or dovetail grooves when incorporating a mechanism for holding the pinion 15a into the cage 14a. This eliminates the need for work such as damaging the protrusions or fitting them into the dovetail grooves, improving productivity. This is particularly true when manufacturing small-sized linear guide units 10a, such as those with rollers 13a having a diameter of less than 4 mm. Furthermore, because the pinion 15a is held in the cage 14a by being sandwiched between the pinion cover 91a, the risk of the pinion 15a becoming disengaged or falling off the cage 14a is significantly reduced. Therefore, this linear guide unit 10a improves productivity.

[0048] In this embodiment, the pinion holding area 83a is provided at the center in the first direction. The roller holding areas 81a, 82a are provided as a pair on both ends of the pinion holding area 83a in the first direction. Therefore, by providing the pinion holding area 83a at the center in the first direction, which is the longitudinal direction, the cage 14a can be guided in a balanced manner in the longitudinal direction. Furthermore, the first raceway member 11a and the second raceway member 12a can appropriately bear the load without causing the portions where the roller holding areas 81a, 82a are provided to be biased in the longitudinal direction.

[0049] In this embodiment, the pinion cover 91a is attached to the pinion holding area 83a by snap fitting. Therefore, when attaching the pinion cover 91a so as to sandwich the pinion 15a, the pinion cover 91a can be attached by utilizing elastic deformation of the material. This simplifies the configuration, improves assembly, and improves productivity.

[0050] In this embodiment, both the first rack 16a and the second rack 17a are plate-shaped, which allows the shapes of both the first rack 16a and the second rack 17a to be simplified, thereby improving productivity.

[0051] In this embodiment, both the first rack teeth 77a and the second rack teeth 79a are provided to protrude in the second direction. This makes it easy to mesh both the first rack teeth 77a provided on the first rack 16a and the second rack teeth 79a provided on the second rack 17a with the external teeth 71a of the pinion 15a in the second direction. This makes it possible to appropriately mesh the external teeth 71a of the pinion 15a with the rack teeth and guide the cage 14a while achieving a compact size and a simplified shape.

[0052] In this embodiment, the cage 14a includes a pair of side stays 51a, 52a, a plurality of pillars 53a spaced apart in the first direction and connecting the pair of side stays 51a, 52a to form the pocket 44a, and retaining claws 55a, 56a that are connected to side wall surfaces 57a, 58a of the pair of side stays 51a, 52a and to side wall surfaces 59a of the pillars 53a, respectively, when viewed from the side where the window portion 45a of the pocket 44a is opened, and that protrude toward the window portion 45a and prevent the roller 13a from falling out of the pocket 44a. Thus, when the roller 13a is placed in the pocket 44a by climbing over the retaining claws 55a, 56a, which prevent the roller 13a from falling out, the force pressing the retaining claws 55a, 56a can be easily distributed in the first and second directions. Specifically, referring particularly to FIG. 9, when the roller 13a is inserted into the pocket 44a from the window portion 45a side, a pushing force is generated on the retaining claws 55a, 56a in the direction indicated by the arrow F1. However, this force F1 is dispersed into a force F2 in the longitudinal direction, which is the first direction, and a force F3 in the direction perpendicular thereto. Since the side stays 51a, 52a are easily bent, particularly in the direction indicated by force F3, they can be deformed with a relatively small force. This reduces the mechanical load on the retaining claws 55a, 56a when the roller 13a is stored, thereby reducing the risk of damage to the retaining claws 55a, 56a.

[0053] In this embodiment, the retaining claws 55a, 56a are provided as a pair on one side stay 51a and the other side stay 52a, which can further reduce the mechanical load on each of the retaining claws 55a, 56a and further reduce the risk of damage to the retaining claws 55a, 56a.

[0054] In this embodiment, the retaining claws 55a, 56a include flat surfaces 61a, 62a that are continuous with the side wall surfaces 57a, 58a of the pair of side stays 51a, 52a and the side wall surface 59a of the pillar portion 53a. This allows the shape of the retaining claws 55a, 56a to be relatively simple, and the area that catches the roller 13a to be relatively large, greatly reducing the risk of the roller 13a falling out of the pocket 44a.

[0055] In this embodiment, when viewed from the side where the window portion 45a of the pocket 44a is open, the shape of the retaining claws 55a, 56a is an isosceles triangle with equal sides at the portions that connect to the side wall surfaces 57a, 58a of the side stays 51a, 52a and the portion that connects to the side wall surface 59a of the pillar portion 53a. Therefore, when installing the roller 13a in the pocket 44a, the load capacity can be distributed equally between the side stays 51a, 52a and the pillar portion 53a. This improves installation ease and productivity.

[0056] Furthermore, the linear guide unit 10a of the present disclosure includes a first track member 11a extending in a first direction, which is the longitudinal direction, and a second track member 12a extending in the first direction and arranged opposite the first track member 11a in a second direction, which is a direction perpendicular to the first direction, and the second track member 12a performs linear movement relative to the first track member 11a in the first direction. The linear motion guide unit 10a includes: a plurality of rollers 13a arranged alternately at intervals in a first direction so that their rolling axes are perpendicular to each other; a cage 14a arranged between the first track member 11a and the second track member 12a in the second direction, with a plurality of pockets 44a for accommodating each roller 13a provided at intervals in the first direction and holding the plurality of rollers 13a; a pinion 15a having a plurality of external teeth 71a provided on its outer periphery and arranged between the first track member 11a and the second track member 12a in the second direction and rotatably supported; a first rack 16a attached to the outer circumferential surface of the first track member 11a and provided with a plurality of first rack teeth 77a that mesh with the external teeth 71a; and a second rack 17a attached to the outer circumferential surface of the second track member 12a and provided with a plurality of second rack teeth 79a that mesh with the external teeth 71a. The retainer 14a includes a pair of side stays 51a, 52a, a plurality of pillar portions 53a that are spaced apart in the first direction and connect the pair of side stays 51a, 52a to form a pocket 44a, and retaining claws 55a, 56a that, when viewed from the side where the window portion 45a of the pocket 44a opens, are connected to side wall surfaces 57a, 58a of one of the pair of side stays 51a, 52a and a side wall surface 59a of the pillar portion 53a and protrude toward the window portion 45a, preventing the roller 13a from falling out of the pocket 44a.

[0057] With this linear motion guide unit 10a, when the roller 13a is accommodated in the pocket 44a by climbing over the retaining claws 55a, 56a, which prevent the roller 13a accommodated in the pocket 44a from falling out, the force pushing against the retaining claws 55a, 56a can be easily dispersed in the first and second directions. Therefore, the mechanical load on the retaining claws 55a, 56a when the roller 13a is accommodated can be reduced, reducing the risk of damage to the retaining claws 55a, 56a.

[0058] (Other embodiments) In the above embodiment, the shape is an isosceles triangle, but it is not limited to this, and the shape may be a triangle with three sides of different lengths, or a polygon. Furthermore, the wall surface constituting the holding claw may be concave in an arc shape or convex in an arc shape when viewed from the side where the window portion of the pocket opens.

[0059] In the above embodiment, a pair of retaining claws are provided, but this is not limiting and only one retaining claw may be provided. In this case, by making the amount of protrusion larger than when a pair of retaining claws are provided, it is possible to more reliably prevent the roller from falling out of the pocket.

[0060] In the above embodiment, the pinion cover is attached to the pinion holding area by snap-fitting, but this is not limiting, and the pinion cover may be attached to the pinion holding area using screws, etc. Also, in the snap-fit ​​structure, fitting claws may be provided in the pinion holding area and fitting grooves may be provided in the pinion cover.

[0061] The present invention is intended to cover a wide range of applications, including those related to the present invention, including those related to the present invention. [Explanation of symbols]

[0062] 10a Linear motion guide unit, 11a First raceway member, 12a Second raceway member, 13a Roller, 14a Cage, 15a Pinion, 16a First rack, 17a Second rack, 21a, 31a First raceway surface, 22a, 32a Second raceway surface, 23a, 33a Recess, 24a, 28a, 30a, 34a, 38a, 40a, 85a Surface, 25a, 35a, 42a End face, 26a, 29a, 36a, 39a Recess, 27a, 37a, 54a, 74a Through hole, 41a Rolling surface, 44a Pocket, 45a, 46a Window, 51a, 52a Side stay, 53a Pillar, 55a, 56a, 63a, 64a Retaining claws, 57a, 58a, 59a side wall surfaces, 61a, 62a, 65a, 66a flat surfaces, 67a jig, 71a external teeth, 72a, 73a rotating shaft, 75a notch, 76a bolt, 77a first rack tooth, 78a groove portion, 79a second rack tooth, 81a, 82a roller retaining area, 83a pinion retaining area, 84a pinion accommodating portion, 86a, 87a rotating shaft accommodating portion, 88a, 89a fitting groove, 91a pinion cover, 92a gap portion, 93a opening, 94a, 95a fitting claws.

Claims

1. a linear motion guide unit comprising: a first track member extending in a first direction which is a longitudinal direction; and a second track member extending in the first direction and disposed opposite to the first track member in a second direction which is a direction perpendicular to the first direction, wherein the second track member performs linear motion in the first direction relative to the first track member, a plurality of rollers arranged alternately at intervals in the first direction so that their rolling axes are perpendicular to each other; a cage that is disposed between the first track member and the second track member in the second direction, that has a plurality of pockets that are spaced apart in the first direction and that accommodate the rollers, and that holds the rollers; a pinion having a plurality of external teeth provided on an outer periphery thereof, the pinion being disposed between the first raceway member and the second raceway member in the second direction and rotatably supported; a first rack attached to the outer peripheral surface of the first track member and provided with a plurality of first rack teeth that mesh with the external teeth; a second rack attached to the outer peripheral surface of the second track member and provided with a plurality of second rack teeth that mesh with the external teeth, The retainer is A pair of side stays; a plurality of pillar portions arranged at intervals in the first direction and connecting the pair of side stays to form the pocket; a retaining claw that is connected to a side wall surface of one of the pair of side stays and a side wall surface of the pillar portion and protrudes toward the window portion when viewed from the side where the window portion of the pocket is opened, and prevents the roller from falling out of the pocket, The linear motion guide unit includes a pair of retaining claws provided on one side of the side stay and the other side of the side stay.

2. 2. The linear motion guide unit according to claim 1, wherein the holding claw includes a flat surface that is continuous with a side wall surface of one of the pair of side stays and a side wall surface of the pillar portion.

3. 3. The linear motion guide unit according to claim 1, wherein the shape of the retaining claw is an isosceles triangle with equal sides at a portion connected to the side wall surface of the side stay and at a portion connected to the side wall surface of the pillar, when viewed from the side where the window portion of the pocket is open.

4. a linear motion guide unit comprising: a first track member extending in a first direction which is a longitudinal direction; and a second track member extending in the first direction and disposed opposite to the first track member in a second direction which is a direction perpendicular to the first direction, wherein the second track member performs linear motion in the first direction relative to the first track member, a plurality of rollers arranged alternately at intervals in the first direction so that their rolling axes are perpendicular to each other; a cage that is disposed between the first track member and the second track member in the second direction, that has a plurality of pockets that are spaced apart in the first direction and that accommodate the rollers, and that holds the rollers; a pinion having a plurality of external teeth provided on an outer periphery thereof, the pinion being disposed between the first raceway member and the second raceway member in the second direction and rotatably supported; a first rack attached to the outer peripheral surface of the first track member and provided with a plurality of first rack teeth that mesh with the external teeth; a second rack attached to the outer peripheral surface of the second track member and provided with a plurality of second rack teeth that mesh with the external teeth, The retainer is a roller holding area for holding the plurality of rollers; a pinion holding area disposed adjacent to the roller holding area in the first direction, the pinion holding area including a pinion accommodating portion configured to accommodate the pinion such that the external teeth mesh with the second rack teeth, The roller holding area and the pinion holding area are integrally formed, the linear motion guide unit includes a pinion cover attached to the pinion holding area so as to sandwich the pinion between itself and the pinion holding area, and so that the external teeth of the pinion cover mesh with the first rack teeth, The retainer is A pair of side stays; a plurality of pillar portions arranged at intervals in the first direction and connecting the pair of side stays to form the pocket; a retaining claw that is connected to a side wall surface of one of the pair of side stays and a side wall surface of the pillar portion and protrudes toward the window portion when viewed from the side where the window portion of the pocket is opened, and prevents the roller from falling out of the pocket, The linear motion guide unit includes a pair of retaining claws provided on one side of the side stay and the other side of the side stay.

5. 5. The linear motion guide unit according to claim 4, wherein the holding claw includes a flat surface that is continuous with a side wall surface of one of the pair of side stays and a side wall surface of the pillar portion.

6. 6. The linear motion guide unit according to claim 4, wherein the shape of the retaining claw is an isosceles triangle with equal sides at a portion connected to the side wall surface of the side stay and at a portion connected to the side wall surface of the pillar, when viewed from the side where the window portion of the pocket is open.

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