Track member for motion guide device and motion guide device

Abstract

To reduce assembly man-hours and weight.SOLUTION: A motion guide device track member 11 includes a top plate portion 20 having a top surface 20a extending in a longitudinal direction and formed as a substantially flat surface, and a pair of wall portions 21, 21 extending from both ends in a lateral direction of the top plate portion 20 in a direction substantially orthogonal to the top surface 20a, and has a cavity portion 22 surrounded in three directions by the top plate portion 20 and the pair of wall portions 21, 21 and penetrating in the longitudinal direction, wherein an open side of the cavity portion 22 is a side installed on a mounting surface 30a. Each of the pair of wall portions 21, 21 has at least one rolling element rolling surface 12 on each of a pair of outer wall surfaces 21a and 21a, and when an imaginary plane V extending in the lateral direction from an opposite 20b of the top plate portion 20 is assumed, the opposite 20b and the rolling element rolling surface 12 are arranged and formed such that the imaginary plane V and at least a part of the rolling element rolling surface 12 intersect each other.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a track member for a motion guide device and a motion guide device. [Background technology]

[0002] Motion guide devices, which use rolling elements such as balls and rollers in the guiding section as mechanical elements to guide the linear and curved motion of moving bodies such as tables, are used in a variety of fields, including robots, machine tools, semiconductor and liquid crystal manufacturing equipment, and medical devices, as they provide nimble movement.

[0003] The motion guide device comprises a track rail as a track member extending in the longitudinal direction, and a movable block as a movable member attached to the track rail via a plurality of rolling elements, thereby allowing the movable block to reciprocate relatively in the longitudinal direction of the track rail. The track rail has a rolling element rolling groove extending along the longitudinal direction. Meanwhile, the movable block has a loaded rolling element rolling groove facing the rolling element rolling groove, and is provided with a rolling element circulation path for circulating the rolling elements. Furthermore, rolling elements are arranged between the rolling element rolling groove of the track rail and the loaded rolling element rolling groove of the movable block so as to roll freely under a load. When the movable block moves linearly relative to the track rail, the rolling elements arranged between the track rail and the movable block roll and circulate endlessly in the rolling element circulation path.

[0004] Recently, in industries that use motion guide devices as machine elements, there has been a desire to reduce the weight of motion guide devices. For example, Patent Document 1 below discloses a conventional technique for reducing the weight of the track rails that constitute a motion guide device. Patent Document 1 discloses a technique in which the track rails of a motion guide device are integrally formed from an extruded aluminum or aluminum alloy material, and a piano wire is inserted longitudinally into an insertion groove provided in a guide section formed on the track surface, so that rollers as rolling elements abut against the piano wire while a moving block reciprocates along the track rail. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-34519 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned track rail has a limit to the surface precision of the rolling element rolling surface, and in order for the rolling elements to move smoothly on the rolling element rolling surface, a piano wire needs to be provided between the rolling elements and the rolling element rolling surface. This poses a problem of increasing the number of parts and assembly steps. Furthermore, in the prior art typified by Patent Document 1 mentioned above, there is still room for further improvement in terms of reducing the weight of motion guide devices including track rails.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a track member for a motion guide device that reduces the number of assembly steps and is lightweight. [Means for solving the problem]

[0008] The track member for a motion guide device according to the present invention comprises a top plate portion having a top surface that extends in the longitudinal direction and is formed as an approximately flat surface, and a pair of wall portions that extend from both ends of the top plate portion in a direction approximately perpendicular to the top surface, and is surrounded on three sides by the top plate portion and the pair of wall portions and has a cavity portion that penetrates in the longitudinal direction, and when viewed from the longitudinal direction, the open side of the cavity portion is the side that is installed on the mounting surface, and the pair of wall portions have at least one rolling element rolling surface on each of a pair of outer wall surfaces that are the surfaces opposite the cavity portion side, along which the rolling elements roll along the longitudinal direction, and the opposite surface and the rolling element rolling surface are positioned and formed so that when an imaginary plane is imagined that is extended in the lateral direction from the opposite surface that is the surface facing the cavity portion of the top plate portion, the imaginary surface and at least a portion of the rolling element rolling surface intersect.

[0009] Furthermore, the present invention can realize a motion guide device comprising the above-mentioned track member for a motion guide device, a plurality of rolling bodies arranged so as to be able to roll freely on the rolling body rolling surface formed on the track member for a motion guide device, and a moving member attached to the track member for a motion guide device so as to be able to move freely relative to the track member for a motion guide device via the plurality of rolling bodies. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a track member for a motion guide device that reduces the number of assembly steps and is lightweight. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partially sectional external perspective view of a motion guide device according to an embodiment of the present invention; [Figure 2] 3 is a cross-sectional view illustrating an endless circulation path provided in the motion guide device according to the present embodiment. FIG. [Figure 3] 1 is a perspective view of the track rail according to the present embodiment, seen from the lower right rear side. FIG. [Figure 4] 1 is a front view of a track rail according to an embodiment of the present invention as viewed from the longitudinal direction. FIG. [Figure 5] 10A to 10C are diagrams illustrating a method of assembling a base-equipped track member for a motion guide device according to the present embodiment. [Figure 6] 1 is a cross-sectional view of a base-equipped track member for a motion guide device according to the present embodiment, as viewed from the longitudinal direction. [Figure 7] 10A to 10C are diagrams showing various modifications that can be made to the track member for a motion guide device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0013] First, the overall configuration of the motion guide device 10 according to this embodiment will be described using Figures 1 and 2. Here, Figure 1 is a partial cross-sectional perspective view of the exterior of the motion guide device 10 according to this embodiment, and Figure 2 is a cross-sectional view illustrating the endless circulation path provided in the motion guide device 10 according to this embodiment. Furthermore, for convenience of explanation, the directions of the motion guide device 10 are defined as shown in Figures 1 and 2 in this specification. However, these directions do not indicate the directions when the motion guide device 10 according to this embodiment is in use, and the motion guide device 10 according to this embodiment can be used in any position. In other words, the directions of "front, back, up, down, left, and right" shown in Figures 1 and 2 are determined solely for convenience of explanation.

[0014] As shown in Figure 1, the motion guide device 10 of this embodiment includes a track rail 11 as a track member for the motion guide device, and a moving block 13 as a moving member attached to the track rail 11 so as to be movable relative to the track rail 11 via a plurality of balls 15 as rolling elements.

[0015] The track rail 11 is an elongated member extending in the longitudinal direction (i.e., the front-rear direction in FIG. 1 ). A pair of outer wall surfaces 21 a, 21 a forming the left and right sides of the track rail 11 are provided with rolling element rolling surfaces 12 as track surfaces on which balls 15 roll, which are formed over the entire front-rear direction length of the track rail 11. The motion guide device 10 illustrated in FIG. 1 is a so-called all-ball type motion guide device in which only balls 15 as multiple rolling elements roll in alignment. However, other types of rolling elements, such as rollers, can be used for the multiple rolling elements used in the motion guide device according to the present invention. The present invention is also applicable to a motion guide device in which the balls 15 are held and aligned by a retainer. Here, the track rail 11 may be formed to extend linearly or curvedly.

[0016] Meanwhile, the movable block 13 is provided with loaded rolling element rolling surfaces 14 as raceway surfaces along which balls 15 roll at positions corresponding to the rolling element rolling surfaces 12 of the track rail 11. The rolling element rolling surfaces 12 of the track rail 11 and the loaded rolling element rolling surfaces 14 of the movable block 13 form a loaded rolling element rolling path 17, on which a plurality of balls 15 are arranged so as to be able to roll under a load. Furthermore, as shown in Fig. 2, the movable block 13 is provided with an unloaded return passage 18 extending parallel to the loaded rolling element rolling path 17 at a predetermined interval, and a direction change path 19 connecting the loaded rolling element rolling path 17 and the unloaded return passage 18. A combination of one loaded rolling element rolling path 17 and one unloaded return passage 18 and a pair of direction change paths 19, 19 connecting them forms one endless circulation path. The plurality of balls 15 are installed in an infinite circulation path consisting of a loaded rolling body rolling path 17, an unloaded return path 18, and a pair of direction change paths 19, 19 so as to be able to circulate infinitely, thereby allowing the moving block 13 to freely move back and forth relative to the track rail 11.

[0017] The overall configuration of the motion guide device 10 according to this embodiment has been described above using Figs. 1 and 2. Next, the characteristic configuration of the track rail 11 in the motion guide device 10 according to this embodiment will be described using Figs. 3 and 4. Here, Fig. 3 is an external perspective view of the track rail according to this embodiment as seen from the lower right rear, and Fig. 4 is a front view of the track rail 11 according to this embodiment as seen from the longitudinal direction. Note that, for ease of description, the direction of the track rail 11 is defined in this specification in the same direction as that of the motion guide device 10 described above.

[0018] 3 and 4, the track rail 11 according to this embodiment includes a top plate portion 20, a pair of wall portions 21, 21, and a pair of bottom plate portions 23, 23. The top plate portion 20 has a top surface 20a extending in the front-rear direction (i.e., the longitudinal direction) and formed as a substantially flat surface, and a counter surface 20b formed below the top surface 20a.

[0019] The pair of wall portions 21, 21 are formed to extend from both left and right ends of the top plate portion 20 in a direction substantially perpendicular to the top surface 20a (i.e., downward). As a result, a hollow portion 22 is formed that is surrounded on three sides by the top plate portion 20 and the pair of wall portions 21, 21 and penetrates in the front-rear direction (i.e., longitudinal direction). In this way, the track rail 11 of this embodiment has the hollow portion 22 that penetrates in the front-rear direction, so that it can be made significantly lighter than conventional track rails.

[0020] When viewed from the front-rear direction (i.e., the longitudinal direction), the track rail 11 has a lower side of the hollow portion 22 that is installed on a mounting surface 30a of a base 30 (described later). The pair of wall portions 21, 21 has a pair of inner wall surfaces 21b, 21b formed on the hollow portion 22 side, and a pair of outer wall surfaces 21a, 21a that are surfaces opposite (on the left and right outer sides) to the pair of inner wall surfaces 21b, 21b. Each of the pair of outer wall surfaces 21a, 21a is formed with one rolling element rolling surface 12, two in total, along which the rolling elements roll in the front-rear direction (i.e., the longitudinal direction). The groove shape of the rolling element rolling surface 12 according to this embodiment is formed in a Gothic arch shape consisting of two circular arcs. That is, in the motion guide device 10 according to this embodiment, the rolling element rolling surface 12 and the loaded rolling element rolling surface 14 are formed in a Gothic arch shape, so that the balls 15 are arranged so that they have the same rated load against the loads acting on the moving block 13 in four directions (radial direction, reverse radial direction, and lateral direction), making it possible to use the motion guide device 10 in any position. Also, the number of grooves on the rolling element rolling surface according to the present invention can be changed as desired depending on the application of the motion guide device 10, etc.

[0021] In this embodiment, the pair of bottom plate portions 23, 23 are formed to protrude from the side where the mounting surfaces 30a of the pair of wall portions 21, 21 are installed, i.e., from the lower end sides of the pair of wall portions 21, 21, toward the inside of the hollow portion 22. The pair of bottom plate portions 23, 23 also have a pair of bottom plate portion inner wall surfaces 23a, 23a formed as vertical surfaces extending in the up-down direction on the hollow portion 22 side.

[0022] In the track rail 11 of this embodiment, when an imaginary plane V extending from the reverse surface 20b of the top plate portion 20 in the left-right direction of the track rail 11 is imagined, the reverse surface 20b and the pair of rolling element rolling surfaces 12, 12 are arranged so that the imaginary plane V intersects with at least a part of the pair of rolling element rolling surfaces 12, 12. With this arrangement, even if the hollow portion 22 is formed to reduce weight, the top plate portion 20 having the reverse surface 20b can reliably receive the load on the rolling element rolling surfaces 12 that receives the rolling load from the multiple balls 15, and therefore it is possible to simultaneously achieve the essentially contradictory effects of maintaining rigidity and reducing weight.

[0023] As a manufacturing method for the track rail 11 according to this embodiment, for example, a method of forming the track rail 11 by roll forming a stainless steel plate can be adopted. This makes it possible to efficiently manufacture the track rail 11 having good surface accuracy of the rolling element rolling surfaces 12, thereby realizing a short delivery time and low cost. In addition to the above manufacturing method, the cavity 22 can also be formed in a conventional track rail that does not have a cavity 22 by performing drilling, grinding, cutting, etc. along the longitudinal direction. In other words, the track member for a motion guide device according to the present invention can be manufactured by any known processing method, and the manufacturing method is not limited.

[0024] The characteristic configuration of the track rail 11 in the motion guide device 10 according to this embodiment has been described above using Figs. 3 and 4. Next, the configuration of the base-equipped track member 50 for a motion guide device, in which a base 30 is attached to the track rail 11 as a track member for a motion guide device, will be described using Figs. 5 and 6. Here, Fig. 5 is a diagram showing a method for assembling the base-equipped track member 50 for a motion guide device according to this embodiment, and Fig. 6 is a cross-sectional view of the base-equipped track member for a motion guide device according to this embodiment as viewed from the longitudinal direction. Note that, for ease of explanation, the direction of the base-equipped track member for a motion guide device is defined herein in the same direction as that of the motion guide device 10 described above.

[0025] The base-equipped track member 50 for a motion guide device according to this embodiment is formed by fixing the track rail 11 to a base 30 that can be attached to the track rail 11. As shown in FIG. 5, the base 30 has a mounting surface 30a that extends in the front-rear direction and is formed as a substantially flat surface. The base 30 also has a plurality of through holes 32 (three in this embodiment) that penetrate the base 30 in the up-down direction. Note that although the base 30 according to this embodiment is made of a metal material, any material such as resin or wood can be used.

[0026] The through hole 32 allows a bolt 33 to be inserted into the through hole 32 from the underside of the base 30. The bolt 33 is formed by a flange portion 33a and a diameter portion 33b. The diameter of the diameter portion 33b of the bolt 33 is formed to be approximately the same as the distance between the pair of inner wall surfaces 23a, 23a of the bottom plate portion of the track rail 11. With the diameter portion 33b of the bolt 33 inserted into the insertion hole 32 from the underside of the base 30, a plate nut 34 serving as a fixing means can be screwed onto the diameter portion 33b from the mounting surface 30a side. The plate nut 34 has a rectangular parallelepiped shape and is formed so that its center penetrates in the up-down direction. The widths of the plate nut 34 in the front-rear and left-right directions are formed to be approximately the same as the distance between the pair of inner wall surfaces 21b, 21b of the track rail 11.

[0027] Next, a method for assembling the base-mounted track member 50 for a motion guide device according to this embodiment will be described. First, the diameter portion 33b of the bolt 33 is inserted into the through-hole 32 from the underside of the base 30, and the plate nut 34 is screwed onto the diameter portion 33b of the bolt 33 from the mounting surface 30a side, thereby forming the protrusion 31 on the mounting surface 30a side. That is, by screwing the plate nut 34 onto the diameter portion 33b of the bolt 33, the protrusion 31 made up of the diameter portion 33b and the plate nut 34 is formed. At this time, it is preferable that the bolt 33 is screwed onto the plate nut 34 so that the height of the plate nut 34 from the mounting surface 30a is approximately the same as the vertical length of the bottom plate portion 23 of the track rail 11.

[0028] From this state, the track rail 11 is slid in the front-rear direction along the mounting surface 30a of the base 30 so that the pair of bottom plate portions 23, 23 of the track rail 11 sandwich the shank 33b of the bolt 33 and the plate nut 34 is housed in the hollow portion 22 of the track rail 11, thereby engaging the pair of bottom plate portions 23, 23 with the protrusion portion 31 consisting of the bolt 33 and the plate nut 34. At this time, in order to prevent the plate nut 34 from interfering with the pair of wall portions 21, 21 of the track rail 11, it is preferable to adjust the position of the plate nut 34 so that the surface perpendicular to the up-down direction is approximately parallel to the insertion direction of the track rail 11, and then slide the track rail 11. After positioning the track rail 11 relative to the base 30, the bolt 33 is tightened from the underside of the base 30, whereby the flange portion 33a of the bolt 33 and the plate nut 34 sandwich the pair of bottom plate portions 23, 23 of the track rail 11 and the base 30, thereby fixing the base 30 and the track rail 11 together.

[0029] As a result, as shown in Fig. 6, the pair of bottom plate portions 23, 23 are sandwiched between the base 30 and the plate nut 34 in the up-down direction, thereby restricting the movement of the track rail 11 in the up-down direction. In addition, the pair of bottom plate portions 23, 23 sandwich the diameter portion 33b of the bolt 33 in the left-right direction, thereby restricting the movement of the track rail 11 in the left-right direction. Furthermore, a frictional force is generated between the plate nut 34 and the pair of bottom plate portions 23, 23 due to the fastening force of the bolt 33, thereby restricting the movement of the track rail 11 in the front-rear direction and the left-right direction. In this way, the track rail 11 can be fixed to the base 30.

[0030] While the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and improvements can be made to the above embodiments.

[0031] In the base-mounted track member 50 for a motion guide device according to the above-described embodiment, the protrusions 31 are formed on the mounting surface 30a of the base 30 using the bolts 33 and the plate nuts 34, the track rail 11 is placed on the base 30 so that the pair of bottom plate portions 23, 23 and the protrusions 31 engage with each other, and the bolts 33 are then tightened to fix the track rail 11 to the base 30. That is, the protrusions 31 are formed using the bolts 33 and the plate nuts 34, and the bolts 33 are used as fixing means for fixing the pair of bottom plate portions 23, 23 to the protrusions 31. However, the base-mounted track member for a motion guide device according to the present invention is not limited to the above-described embodiment, and any form of conventionally known protrusions and fixing means can be employed.

[0032] Furthermore, for example, the track rail 11 according to the above-described embodiment is characterized by including the top plate portion 20, the pair of wall portions 21, 21, and the pair of bottom plate portions 23, 23, and the pair of bottom plate portions 23, 23 are formed facing inward of the hollow portion 22. However, the track rail as a track member for a motion guide device according to the present invention is not limited to the above-described embodiment.

[0033] For example, FIG. 7 shows modified shapes that the track member for a motion guide device according to the present invention can take. Here, FIG. 7 is a diagram illustrating various modified shapes that the track member for a motion guide device according to the present invention can take. In FIG. 7, as shown in sub-view (a) of the figure, a chamfered portion 23b can be formed from the lower side of the bottom plate portion 23 to the inner surface of the hollow portion 22. In this case, the chamfered portion 23b can be effective as a burr prevention member. Furthermore, as shown in sub-view (b) of the figure, the track member for a motion guide device according to the present invention can have the pair of bottom plate portions 23, 23 formed facing outward from the hollow portion 22. In either case, when an imaginary plane V is imagined extending from the opposite surface 20b of the top plate portion 20 in the left-right direction of the track rail 11, the opposite surface 20b and the pair of rolling element rolling surfaces 12, 12 should be arranged and formed so that at least a portion of the pair of rolling element rolling surfaces 12, 12 intersects with the imaginary plane V.

[0034] In other words, the track member with base for a motion guide device and the track member for a motion guide device according to the present invention can adopt a variety of shapes within the scope of having the above-mentioned characteristics, and can be said to be components with a high degree of design freedom.

[0035] It is clear from the claims that such modifications and improvements may also be included within the technical scope of the present invention. [Explanation of symbols]

[0036] 10 motion guide device, 11 track rail (motion guide device track member), 12 rolling element rolling surface, 13 moving block (moving member), 14 loaded rolling element rolling surface, 15 ball (rolling element), 17 loaded rolling element rolling path, 18 unloaded return path, 19 direction change path, 20 top plate portion, 20a top surface, 20b reverse surface, 21 wall portion, 21a outer wall surface, 21b inner wall surface, 22 cavity portion, 23 bottom plate portion, 23a bottom plate portion inner wall surface, 23b chamfered portion, 30 base, 30a mounting surface, 31 protrusion portion, 32 through hole, 33 bolt (fixing means), 33a flange portion, 33b diameter portion, 34 plate nut (fixing means), 50 base-attached track member for motion guide device, V imaginary surface.

Claims

1. a top plate portion extending in the longitudinal direction and having a top surface formed as a substantially flat surface; a pair of wall portions extending from both ends of the top plate portion in a short side direction in a direction substantially perpendicular to the top surface; Equipped with a track member for a motion guide device, the track member being surrounded on three sides by the top plate portion and the pair of wall portions and having a hollow portion penetrating in the longitudinal direction, the open side of the hollow portion being the side to be installed on an attachment surface when viewed from the longitudinal direction, The pair of wall portions each have at least one rolling element rolling surface on which a rolling element rolls along the longitudinal direction on a pair of outer wall surfaces that are surfaces opposite to the hollow portion side, A track member for a motion guide device, characterized in that when an imaginary plane is imagined extending in the short direction from the other surface, which is the surface facing the hollow portion of the top plate portion, the other surface and the rolling element rolling surface are positioned and formed so that at least a portion of the imaginary plane intersects with the rolling element rolling surface.

2. 2. The track member for a motion guide device according to claim 1, The pair of wall portions have a pair of bottom plate portions at ends on the side where the mounting surface is installed, A track member for a motion guide device, characterized in that the pair of bottom plate portions are formed toward the inside of the hollow portion.

3. 2. The track member for a motion guide device according to claim 1, The pair of wall portions have a pair of bottom plate portions at ends on the side where the mounting surface is installed, A track member for a motion guide device, characterized in that the pair of bottom plate portions are formed facing outward from the hollow portion.

4. A track member for a motion guide device according to any one of claims 1 to 3, a plurality of rolling elements that are rollably disposed on the rolling element rolling surface formed on the motion guide device track member; a moving member attached to the track member for the motion guide device via the plurality of rolling elements so as to be relatively movable; A motion guide device comprising:

Images