Linear guide

Abstract

To provide a linear guide in which a lubrication unit can stably supply a lubricant for a long period.SOLUTION: A lubricant supply member is formed in a generally C-shape equipped with a pair of sleeve portions formed at left and right both sides surfaces positions of a guide rail, and a coupling portion coupling the pair of sleeve portions. The pair of sleeve portions has a projecting portion capable of sliding with a rail side raceway surface of the guide rail. A lubrication unit is equipped with a pair of side surface pressing means that are attached to a side wall of a case provided on the outer side in a width direction of a slider with respect to the pair of sleeve portions, and respectively press the pair of sleeve portions inward in the width direction of the slider.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a linear guide, and more particularly to a linear guide capable of supplying lubricant to contact portions of a guide rail, a slider, and rolling elements over a long period of time. [Background technology]

[0002] Conventionally, a linear guide includes a guide rail extending in the axial direction and a slider mounted on the guide rail so as to be movable relative to the guide rail. The slider moves relative to the guide rail in the axial direction via a plurality of rolling elements (balls) that circulate between rolling element rolling grooves formed in the guide rail and the slider. Such linear guides are widely used in linear motion mechanisms in various production facilities. To ensure stable use of this linear guide over a long period of time, it is important to supply a sufficient amount of lubricant to the rolling element rolling grooves and the balls to maintain a good lubrication state.

[0003] Patent Document 1 describes a linear guide bearing device in which a porous lubricant supply member containing a lubricant is housed in a case and attached to the end of a slider, and lubricant is supplied from the lubricant supply member that comes into contact with the rolling element rolling grooves of a guide rail. In Patent Document 2, a reinforcing plate, a lubricant-containing member, and a side seal are secured to the outer surface of the end cap in an overlapping state, starting from the side closest to the end cap. The lubricant-containing member is formed in a C-shape to fit the end cap, and a ring-shaped member with an outer diameter larger than the inner diameter is fitted into a through hole formed at the connecting portion with an open top, thereby expanding the through hole and pressing both sleeve portions against the guide rail. In addition, a ring-shaped member is fitted into each of the through holes with an open outer surface side of both sleeve portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-46529 [Patent Document 2] Japanese Patent Application Publication No. 09-112551 Summary of the Invention [Problem to be solved by the invention]

[0005] 8, in the lubrication unit 100 of Patent Document 1, a lubricant supplying member 101 containing a lubricant is housed in a case 103 integrally formed with a cylindrical portion 104. The cylindrical portion 104 of the case 103 is fitted into a recess 102 formed in the upper portion of the lubricant supplying member 101, and the upper end of the lubricant supplying member 101 is pressed and deformed outward in the width direction of the slider, and the back surface of a sliding portion 105 of the lubricant supplying member 101 is pressed by pressing portions 106 provided on both side surfaces of the case 103 and pressed against rolling element rolling grooves 108 of a guide rail 107, thereby supplying the lubricant.

[0006] However, if the amount of lubricant impregnated in the lubricant supplying member 101 decreases over a long period of use, the lubricant supplying member 101 will shrink (contract) toward the guide rail 107, the pressing force of the cylindrical portion 104 and the pressing portion 106 will decrease, and the contact state between the lubricant supplying member 101 and the rolling element rolling groove 108 of the guide rail 107 will change, and there is a risk that sufficient lubrication will not be maintained. In particular, if the lubricant content of the lubricant supplying member 101 is very high, the dimensional change of the lubricant supplying member 101 due to the decrease in lubricant will be significant, increasing the possibility of the above-mentioned problems occurring.

[0007] 9(a), in a lubrication unit 200 described in Patent Document 2, a lubricant supplying member 201 includes a generally U-shaped upper groove 202 formed on the upper portion, a pair of generally U-shaped lateral grooves 203 formed on both side surfaces, and a sliding portion 208 that slides against a rolling element rolling groove 207 of a guide rail 206. An upper ring 204 is installed in the upper groove 202, and a side ring 205 is installed in each of the pair of lateral grooves 203. Screws (not shown) are inserted into the side rings 205 to secure a side seal (not shown) and the lubrication unit 200 to the slider. Therefore, the relative positions of the side ring 205 and the guide rail 206 are fixed via the rolling elements (not shown).

[0008] 9(b), when the amount of lubricant impregnated in the lubricant supplying member 201 decreases due to long-term use, the dimensions of the lubricant supplying member 201 decrease from the state shown by the dashed line in the figure to the state shown by the solid line in the figure. At that time, because the position of the side ring 205 is fixed, the lubricant supplying member 201 deforms in the direction of the arrow toward the side ring 205. As a result, the contact state between the sliding portion 208 of the lubricant supplying member 201 and the rolling element rolling groove 207 of the guide rail 206 changes, and there is a risk that sufficient lubrication will not be maintained.

[0009] The present invention has been made in view of the above-mentioned problems, and its object is to provide a linear guide in which a lubrication unit can stably supply lubricant over a long period of time. [Means for solving the problem]

[0010] The above object of the present invention can be achieved by the following configuration. (1) a guide rail; a slider that slidably engages with the guide rail so as to straddle the guide rail; A linear guide comprising: a lubrication unit having a lubricant supply member that can be impregnated with a lubricant; and a case that houses the lubricant supply member, the lubricant unit being attached to an end of the slider in an axial direction, the lubricant supply member is formed in a substantially C-shape and includes a pair of sleeve portions formed on both left and right side surfaces of the guide rail and a connecting portion connecting the pair of sleeve portions, the pair of sleeve portions having protrusions that can slide against the rail-side raceway surface of the guide rail, A linear guide characterized in that the lubrication unit is attached to a side wall of the case located on the outer side of the slider in the width direction relative to the pair of sleeve portions, and is provided with a pair of side pressing means that respectively press the pair of sleeve portions inward in the width direction of the slider. (2) A linear guide as described in (1), characterized in that each of the side pressing means has a female thread portion formed on the side wall of the case and penetrating the slider in the width direction, and a screw member inserted into the female thread portion and protruding from the inner surface of the side wall in the width direction to press the sleeve portion. (3) The linear guide according to (1), wherein each of the side pressing means is an elastic member disposed on the inner side surface in the width direction of the side wall of the case and pressing the sleeve portion. (4) The lubricant supplying member has a recess formed above the guide rail, The linear guide described in any one of (1) to (3) is characterized in that the lubrication unit includes an upper pressing means arranged within the recess so as to allow the connecting portion to move the slider in the vertical direction and press the recess outward in the width direction of the slider. (5) The linear guide according to any one of (1) to (4), wherein the protrusion has a chamfer formed on an edge portion of an end face in the longitudinal direction of the slider. [Effects of the Invention]

[0011] According to the linear guide of the present invention, even if the amount of impregnated lubricant decreases over long-term use and the dimensions of the lubricant supplying member become smaller, the pair of side pressing means press the pair of sleeves of the lubricant supplying member inward in the width direction of the slider, thereby ensuring the force with which the protrusions of the lubricant supplying member press against the rail-side raceway surface, thereby enabling the lubrication unit to stably supply lubricant over a long period of time. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view of a linear guide according to the present invention; [Figure 2] FIG. 2 is a perspective view of the slider shown in FIG. [Figure 3] FIG. 3 is a partially exploded perspective view of the slider shown in FIG. 2. [Figure 4] FIG. 4 is an exploded perspective view of a lubricant supplying member and a case of the lubrication unit shown in FIG. 3. [Figure 5] 10 is a side view illustrating the dimensional relationship between a recess of a lubricant supplying member housed in a case and a cylindrical portion of the case. FIG. [Figure 6] 4 is a side view showing a deformation state of a lubricant supplying member due to a reduction in the amount of contained lubricant in the lubrication unit of the first embodiment. FIG. [Figure 7] FIG. 10 is a side view showing a lubricant supplying member and a case of a lubrication unit according to a second embodiment, together with a deformed state of the lubricant supplying member. [Figure 8] FIG. 1 is a side view of a conventional lubrication unit. [Figure 9] FIG. 1(a) is a side view of another conventional lubrication unit, and FIG. 1(b) is a side view showing a state in which a lubricant supplying member is deformed due to a reduction in the amount of contained lubricant. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, linear guides according to each embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the vertical direction and width direction of the slider respectively refer to the directions in a state in which the slider is assembled to a guide rail arranged with the longitudinal direction horizontal, and the width direction of the slider is the direction perpendicular to the longitudinal direction of the guide rail and the vertical direction of the slider, and is also referred to as the left-right direction (see FIG. 1). The longitudinal direction is also referred to as the axial direction.

[0014] (First embodiment) As shown in FIG. 1, the linear guide 10 of the first embodiment comprises a linear guide rail 20 and a slider 30 assembled to straddle the guide rail 20 and slidably engaged with it via a plurality of rolling elements (balls) not shown.

[0015] On both side surfaces 23 of the guide rail 20, rail-side track surfaces 21 having an approximately semicircular or gothic arch cross section are formed in the axial direction, and on the ridge where the top surface 24 of the guide rail 20 intersects with both side surfaces 23, rail-side track surfaces 22 having an approximately quarter-circular arc cross section are formed in the axial direction.

[0016] As shown in Figures 2 and 3, the slider 30 consists of a slider body 31, end caps 32 attached to both axial ends of the slider body 31, and lubrication units 33 attached to the axial ends of each end cap 32.

[0017] The slider body 31 is formed in a substantially C-shape, and has slider-side raceway surfaces (not shown) on the inner surfaces of both sleeves that face the rail-side raceway surfaces 21, 22 of the guide rail 20, as well as rolling element return paths. The rail-side raceway surfaces 21, 22 and the slider-side raceway surfaces guide the rolling elements so that they can roll freely, and support the load acting on the slider 30 via the rolling elements. The end cap 32, which is formed in a substantially C-shape, has a curved path (not shown) that connects the slider-side raceway surfaces of the slider body 31 with the rolling element return path, and the rail-side raceway surfaces 21, 22, the slider-side raceway surface, the rolling element return path, and the curved paths at both ends form a rolling element circulation path. A plurality of balls are loaded in the rolling element circulation path so that they can roll freely.

[0018] 3 and 4, the lubrication unit 33 includes a case 40 made of synthetic resin, a lubricant supplying member 50 housed in the case 40, and a side seal 60.

[0019] The side seal 60 is a generally C-shaped steel plate that matches the outer shape of the end cap 32, and both sleeve portions 62 thereof have through holes 61 for mounting screws, and a connecting portion 63 that connects both sleeve portions 62 has a through hole 64 for a grease nipple. The side seal 60 and the guide rail 20 are not in contact with each other, and an elastic body 65 such as nitrile rubber or grease-containing polyurethane rubber is provided inside the C-shaped portion to seal the gap between the slider 30 and the guide rail 20. Grease for lubricating the rolling elements and each raceway surface can be injected into the rolling element circulation path through a grease nipple, and in the initial state (when the linear guide 10 is fully assembled), the rolling element circulation path is filled with grease.

[0020] The lubricant supplying member 50 is formed in a generally C-shape so as to face the upper surface 24 of the guide rail 20 and both side surfaces 23, including the rail-side raceway surfaces 21 and 22. That is, the lubricant supplying member 50 also includes a pair of sleeve portions 58 formed on both the left and right side surfaces of the guide rail 20, and a connecting portion 59 formed above the guide rail 20 and connecting the pair of sleeve portions 58. The lubricant supplying member 50 is formed of a porous material such as rubber or synthetic resin, a tangled fiber material, or the like, and is impregnated with a lubricant. Examples of lubricants that can be used include mineral oil, synthetic oil, and grease. Examples of synthetic resins that can be used include polyurethane, polyethylene, and polypropylene. Examples of the tangled fiber material include wool felt, polyester fiber, nylon fiber, and acrylic fiber.

[0021] From the viewpoint of long-term use, the amount of lubricant impregnated in the lubricant supplying member 50 is preferably 70% by weight or more. Furthermore, the upper limit of the amount of lubricant impregnated is preferably 85% by weight or less, taking into consideration the strength of the lubricant supplying member 50. For example, in one example of this embodiment, the lubricant supplying member 50 is molded from a mixture of polyethylene and mineral oil in a weight ratio of 15:85.

[0022] Approximately semicircular protrusions 51 are provided on both inner surfaces of the pair of sleeve portions 58 of the lubricant supplying member 50, for supplying lubricant by sliding against the rail-side raceway surface 21 of the guide rail 20. Furthermore, quarter-circular arc protrusions 52 are provided on inner corners between the pair of sleeve portions 58 and the connecting portion 59, for supplying lubricant by sliding against the rail-side raceway surface 22 of the guide rail 20.

[0023] Furthermore, an upwardly opening recess 53 is formed in the approximate center of the connecting portion 59 of the lubricant supplying member 50. The recess 53 is formed in an approximately U-shape with two parallel planes facing each other in the width direction. Furthermore, both outer surfaces of the pair of sleeve portions 58 of the lubricant supplying member 50 extend in the up-down direction and are positioned more inward in the width direction than both outer surfaces of the connecting portion 59 so as not to interfere with the side walls 45 of the case 40, which will be described later.

[0024] 4, chamfered portions 51a, 52a are formed on the edge portions of the end faces in the thickness direction of the protrusions 51, 52, respectively. When assembling the slider 30 of the linear guide 10 to a mechanical device, it may be removed from the guide rail 20 and then reattached to the guide rail 20. At that time, there is a possibility that the edge portions of the end faces of the protrusions 51, 52 of the lubricant supplying member 50 may interfere with the edges of the end faces of the rail-side raceway surfaces 21, 22 of the guide rail 20. However, by providing the chamfered portions 51a, 52a, this interference can be prevented, thereby improving the ease of assembly.

[0025] The case 40 is manufactured by injection molding a hard resin such as polyacetal or polyamide, and is formed in a generally C-shape with approximately the same size as the end cap 32. The case 40 defines a storage section 43 for storing the lubricant supplying member 50, with an outer peripheral wall 41 that covers the outer periphery of the lubricant supplying member 50 to be housed therein, and an end wall 42 that covers the axial end face of the lubricant supplying member 50.

[0026] At the top of the storage section 43, approximately in the center in the left-right direction, a cylindrical section 44 serving as upper pressing means is formed continuous with the outer peripheral wall 41 and the end wall 42. Furthermore, at the portions facing the pair of sleeve sections 58 on both the left and right sides of the storage section 43, a pair of side walls 45 formed integrally with the outer peripheral wall 41 are formed symmetrically continuous with the end walls 42. The side walls 45 are provided with screw insertion holes 47 for screwing the lubrication unit 33 to the slider body 31. The case 40 may be made by cutting or pressing a metal material such as steel or aluminum.

[0027] 5, a female screw portion 49 is formed on the side wall 45 of the case 40 at a height position substantially equal to that of the protrusion 51, penetrating the side wall 45 in the width direction of the slider. A screw member 70 is inserted into the female screw portion 49, protruding from the inner surface of the side wall 45 in the width direction to press the sleeve portion 58. Each female screw portion 49 and each screw member 70 constitutes a pair of side pressing means.

[0028] Then, the cylindrical portion 44 of the case 40 is fitted into the recess 53 of the lubricant supply member 50, and the screw members 70 are abutted against the outer surfaces of the pair of sleeve portions 58, respectively, to store the lubricant supply member 50 in the storage portion 43 of the case 40.

[0029] In this way, by storing the lubricant supplying member 50 in the case 40, it is possible to prevent the lubricant supplying member 50 from being damaged during handling. In particular, when the amount of lubricant impregnated in the lubricant supplying member 50 is 70% by weight or more, the amount of resin decreases accordingly, and the strength of the lubricant supplying member 50 decreases, so the use of the case 40 is effective.

[0030] Furthermore, since the outer diameter D of the cylindrical portion 44 is set larger than the inner width (left-right width) D1 of the recess 53, the cylindrical portion 44 is press-fitted into the recess 53 with an interference in the width direction. As a result, a pressing force acts on the recess 53 in a direction that widens the inner width of the recess 53, and as a result, the left-right central portion of the lubricant supplying member 50 (connecting portion 59) deforms to become convex upward, and accordingly, the left and right sleeve portions 58 also deform to approach each other in the left-right direction. Furthermore, since the screw members 70 press the outer surfaces of the left and right sleeve portions 58, the left and right sleeve portions 58 are deformed so as to approach each other in the left-right direction.

[0031] The cylindrical portion 44 applies a pressing force in the width direction to the recessed portion 53, but is allowed to move up and down without being restricted. Therefore, the connecting portion 59 (lubricant supplying member 50) can move slightly up and down within the storage portion 43 of the case 40. In this embodiment, the cylindrical portion 44 is provided continuous with the outer peripheral wall 41 of the case 40, and therefore the outer diameter D of the cylindrical portion 44 is given by the opposing arcuate surfaces.

[0032] Therefore, the protrusions 51, 52 of the lubricant supplying member 50 reliably supply lubricant to the rail-side raceway surfaces 21, 22. The pressing force of the protrusions 51, 52 against the rail-side raceway surfaces 21, 22 is adjusted by the dimensions of the recess 53 and the cylindrical portion 44, and the protrusion amount of the screw member 70.

[0033] Furthermore, in the case 40 of this embodiment, the lower surface of the cylindrical portion 44 is horizontally cut out to provide a flat portion 48. This increases the distance between the upper surface 24 of the guide rail 20 and the flat portion 48, which is the lower surface of the cylindrical portion 44, and allows the width S of the lubricant supplying member 50 disposed between the upper surface 24 and the flat portion 48 to be increased, thereby improving the strength of the lubricant supplying member 50. Furthermore, even if the lubricant content is increased, the risk of deformation or breakage of the lubricant supplying member 50 is reduced, making it easier to handle.

[0034] In the linear guide 10 configured as described above, when the slider 30 moves on the guide rail 20, the balls in the slider 30 repeatedly circulate within the rolling element circulating path. At this time, the protrusions 51, 52 of the lubricant supplying member 50 come into sliding contact with parts of the rail-side raceway surfaces 21, 22 of the guide rail 20, causing the lubricant impregnated in the lubricant supplying member 50 to seep out and automatically supply the lubricant to the rail-side raceway surfaces 21, 22 and the balls. As a result, even if the grease previously filled inside the rolling element circulating path decreases, a good lubricated state is maintained, and the linear guide 10 operates stably and smoothly for a long period of time.

[0035] Furthermore, when the linear guide 10 is used for a long period of time, the amount of lubricant impregnated in the lubricant supplying member 50 decreases, and as shown in FIG. 6, the dimensions of the lubricant supplying member 50 decrease almost uniformly from the state shown by the dashed line in the figure to the state shown by the solid line in the figure.

[0036] However, even if the dimensions of the lubricant supply member 50 are reduced, by tightening the screw member 70 into the female thread portion 49, the lubricant supply member 50 can be reliably brought into contact with the guide rail 20, and a good lubricated state can be maintained for a long period of time. Furthermore, even if the lubrication condition is poor and the lubricant supply member 50 at the rail contact point is worn more than expected, the pressing force of the screw member 70 can be adjusted, so the lubricant supply member 50 can be reliably brought into contact with the rail track surfaces 21, 22. Moreover, because the lubricant supplying member 50 is capable of vertical displacement relative to the case 40, it is possible to absorb any vertical assembly error between the guide rail 20 and the slider 30 during assembly of the linear guide 10, thereby ensuring that the lubricant supplying member 50 comes into reliable contact with the rail track surfaces 21, 22. Furthermore, even if the lubricant supplying member 50 shrinks slightly due to long-term use, the lubricant supplying member 50 can maintain stable contact with the rail track surfaces 21, 22 by moving to an optimal vertical position relative to the guide rail 20.

[0037] In this embodiment, the screw members 70 protrude from the widthwise inner surfaces of the side walls 45 in advance and press against the sleeve portions 58, but in the initial state after the lubricant supplying member 50 is assembled into the case 40, the screw members 70 may be retracted from the widthwise inner surfaces of the side walls 45, so that the side walls 45 of the case 40 press against the sleeve portions 58. When the dimensions of the lubricant supplying member 50 become smaller after long-term use, the screw members 70 can be tightened to reliably bring the lubricant supplying member 50 into contact with the guide rail 20, thereby maintaining a good lubricated state for a long period of time.

[0038] (Second embodiment) 7 is a side view showing the lubricant supply member and the case of the lubrication unit of the second embodiment, together with the deformed state of the lubricant supply member. In the lubrication unit 33A of this embodiment, the side seal 60 has the same configuration as that of the first embodiment, and therefore the description thereof is omitted.

[0039] In the lubrication unit 33A of the second embodiment, resin balls 80 serving as elastic members are provided on the side walls 45 of the case 40a as a pair of side pressing means, instead of the screw members 70 that advance and retreat from the female threaded portion 49 of the first embodiment. The resin balls 80 are formed so as to protrude from recesses 46 formed on both inner surfaces of the side walls 45 and press against the outer surfaces of the sleeve portions 58.

[0040] Therefore, in this embodiment as well, when the linear guide 10 is used for a long period of time, the lubricant impregnated in the lubricant supplying member 50 decreases, and as shown in FIG. 7, the dimensions of the lubricant supplying member 50 decrease almost uniformly from the state shown by the dashed line in the figure to the state shown by the solid line in the figure.

[0041] However, even if the dimensions of the lubricant supply member 50 are reduced, the resin ball 80 presses against the outer surface of the sleeve portion 58, ensuring that the lubricant supply member 50 comes into contact with the guide rail 20, thereby maintaining a good lubricated state for a long period of time. Furthermore, even if the lubrication condition is poor and the lubricant supply member 50 at the rail contact point wears out more than expected, the resin ball 80 can automatically adjust the pressing force, so that the lubricant supply member 50 can be reliably brought into contact with the rail track surface. In this embodiment, the elastic member may be something other than a resin ball, as long as it presses the sleeve portion 58 even if the dimensions of the lubricant supplying member 50 are reduced. The other configurations and operations are the same as those of the first embodiment.

[0042] The present invention is not limited to the above-described embodiments, and modifications and improvements are possible as appropriate. For example, the lubrication unit in the above embodiment is configured to have an upper pressing means and a pair of side pressing means, but the lubrication unit of the present invention is not limited to this and may be configured to have only a pair of side pressing means without providing an upper pressing means. Moreover, rollers may be used as the rolling elements instead of balls. [Explanation of symbols]

[0043] 10 Linear guide 20 Guide rail 21, 22 Rail side raceway surface 30 sliders 33,33A Lubrication Unit 40 cases 44 Cylindrical portion (upper pressing means) 45 Side wall 49 Female thread 50 Lubricant supply member 51,52 protrusion 53 Recess 58 Sleeves 59 Connecting part 70 Screw member (side pressing means) D Outer diameter D1 inner width

Claims

1. Guide rails and a slider that slidably engages with the guide rail so as to straddle the guide rail; A linear guide comprising: a lubrication unit having a lubricant supply member that can be impregnated with a lubricant; and a case that houses the lubricant supply member, the lubricant unit being attached to an end of the slider in an axial direction, the lubricant supply member is formed in a substantially C-shape and includes a pair of sleeve portions formed on both left and right side surfaces of the guide rail and a connecting portion connecting the pair of sleeve portions, the pair of sleeve portions having protrusions that can slide against the rail-side raceway surface of the guide rail, the lubrication unit includes a pair of side pressing means provided on side walls of the case that are provided on the outer sides of the pair of sleeve portions in the width direction of the slider, and that press the pair of sleeve portions inward in the width direction of the slider, respectively; A linear guide characterized in that each side pressing means has a female threaded portion formed on a side wall of the case and penetrating the slider in the width direction, and a screw member inserted into the female threaded portion and protruding from the inner surface of the side wall in the width direction to press the sleeve portion.

2. the lubricant supplying member has a recess formed above the guide rail, The linear guide according to claim 1, characterized in that the lubrication unit includes an upper pressing means arranged within the recess so as to allow the connecting portion to move the slider in the vertical direction and to press the recess outward in the width direction of the slider.

3. 3. The linear guide according to claim 1, wherein the protrusion has a chamfer formed on an edge of an end surface in the longitudinal direction of the slider.

Images