Linear guide device

Abstract

To provide a linear guide device that is excellent in repeated positioning accuracy and exhibits excellent operability.SOLUTION: A linear guide device 10 includes: a guide rail 1; a slider 2 assembled to the guide rail 1; and a plurality of rolling elements filled into a rolling element rolling passage 23 comprising a load rolling passage 22 and a no-load rolling passage 21 so as to be capable of freely rolling. The plurality of rolling elements comprises: a plurality of steel balls 6; and a plurality of spacer balls 16 having a modulus of elasticity that is smaller than that of the steel ball 6, and disposed so as to satisfy a prescribed expression.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a linear guide device used in measuring machines, machine tools, etc., for guiding a reciprocating object in the direction of its movement. [Background technology]

[0002] Conventionally, linear guides generally include a guide rail with rail-side rolling grooves on its left and right side surfaces, a slider with slider-side rolling grooves provided at positions facing the rail-side rolling grooves of the guide rail, and a load-bearing rolling path formed by the rail-side rolling groove and the slider-side rolling groove, and a rolling element return path provided inside the slider, filled with a large number of rolling elements that can roll in these rolling paths. End caps are attached to both axial ends of the slider, and direction-changing paths are formed inside the end caps for changing the direction of the rolling elements. The rolling elements roll in the rolling path consisting of the load-bearing rolling path, rolling element return path, and direction-changing path, thereby moving the slider relative to the guide rail in the axial direction. After changing direction inside the end caps, the rolling elements that roll in the rolling path return to their original positions through the rolling element return path formed inside the slider.

[0003] In such linear guides, the difference in the amount of movement between the rolling elements entering and leaving the loaded rolling path causes the rolling elements to compete with or push against each other, resulting in clogging and reduced operability. Therefore, in order to improve the operability of the rolling guide device, there have been disclosed devices in which spacers of various shapes are arranged between adjacent rolling elements.

[0004] For example, Patent Document 1 describes a linear motion device in which a cage is interposed between adjacent circulating balls. The cage has two concave ball receiving portions back to back, and a ball hole is provided in the center of the ball receiving portion. Spacer balls, which have a much smaller diameter than the circulating balls, are rotatably fitted into the ball holes with both sides exposed. In the linear motion device described in Patent Document 1, when adjacent circulating balls come into contact with the spacer balls simultaneously, the sliding resistance between the circulating balls and the ball receiving portions decreases, resulting in suppression of torque fluctuations in the linear motion device.

[0005] Furthermore, Patent Document 2 discloses a rolling guide device in which the rolling elements are composed of a plurality of balls and a plurality of spacer balls made of an elastic material, and the spacer balls are arranged between the plurality of balls. In Patent Document 2, by using the spacer balls, the pushing of the balls in the circulation path is resolved by the elastic deformation of the spacer balls, thereby preventing malfunction of the linear guide device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-247619 [Patent Document 2] International Publication No. 2006 / 035947 Summary of the Invention [Problem to be solved by the invention]

[0007] In the linear motion device described in Patent Document 1, the spacer balls must be held so that they do not come into contact with adjacent circulating balls at the same time under normal conditions, and must be shaped so that adjacent circulating balls come into contact with the spacer balls only when the ball receiving portion is deformed by a predetermined amount due to the pressing force of the circulating balls. This makes the spacer design complicated, and there is a risk that the cage may collapse due to wear, resulting in malfunction.

[0008] In addition, rolling elements are usually arranged so that there is a gap between adjacent rolling elements, which prevents clogging due to the rolling elements competing with each other. However, when adjacent rolling elements are arranged so that there is a gap between them, if a ball slips, the ball may become displaced, which may reduce repeatable positioning accuracy.

[0009] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a linear guide device that has excellent repeatability in positioning accuracy and excellent operability. [Means for solving the problem]

[0010] The above object of the present invention can be achieved by the following configuration of a linear guide device. (1) a guide rail having a rail-side track groove on its side; a slider assembled to the guide rail and having a slider-side raceway groove facing the rail-side raceway groove; a plurality of rolling elements packed in a rolling element rolling path that is free to roll, the rolling element rolling path comprising a loaded rolling path formed by the rail-side raceway groove and the slider-side raceway groove, and an unloaded rolling path that is provided in the slider and connects one end of the loaded rolling path to the other end, A linear guide device in which one of the guide rail and the slider moves relative to the other as the rolling elements roll, The plurality of rolling elements are composed of a plurality of load elements and a plurality of elastic elements having a smaller elastic modulus and diameter than the load elements, and the number of the load elements is M, the number of the elastic elements is N, the total number of the rolling elements is L=M+N, and each gap between the adjacent rolling elements is d i When

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[0011] According to the present invention, it is possible to provide a linear guide device that has excellent repeatability in positioning accuracy and excellent operability. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a linear guide device according to one embodiment of the present invention, with a rolling element rolling path partially cut away. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the linear guide device shown in FIG. [Figure 3] FIG. 3 is a schematic view showing a cross section taken along line IV-IV in FIG. [Figure 4] FIG. 4 is a diagram for explaining the gap between adjacent rolling elements. [Figure 5] FIG. 5 is a diagram for explaining the total amount of deformation of the rolling elements. DETAILED DESCRIPTION OF THE INVENTION

[0013] The linear guide device according to the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and can be modified as appropriate without departing from the spirit and scope of the present invention.

[0014] First, a linear guide device according to a first embodiment of the present invention will be described with reference to FIGS.

[0015] The linear guide device 10 includes a metal guide rail 1 that extends in one direction, and a slider 2 that has a generally U-shaped cross section and is assembled so as to straddle the guide rail 1 and is movable in the axial direction relative to the guide rail 1. In this specification, the front-to-rear direction refers to the direction in which the slider 2 moves along the guide rail 1, and the left-to-right direction refers to the width direction of the slider 2 attached to the guide rail 1.

[0016] Two rail-side raceway grooves 3 extending in the axial direction are formed on the left and right side surfaces of the guide rail 1. The slider 2 includes a slider body 9 having sleeve portions 4 on both the left and right sides of the guide rail 1, and a pair of end caps 5 attached to one end and the other end of the slider body 9 in the front-rear direction.

[0017] Two slider-side raceway grooves 7 are formed on each of the left and right sides of the inner surface of the sleeve portion 4 of the slider body 9, facing the rail-side raceway grooves 3 of the guide rail 1. The rail-side raceway grooves 3 and the slider-side raceway grooves 7 arranged opposite each other form two load rolling paths 22 on each of the left and right sides. The slider 2 is provided with an unloaded rolling path 21 that connects one end of the loaded rolling path 22 to the other end, and the loaded rolling path 22 and the unloaded rolling path 21 form a rolling element rolling path 23 .

[0018] The end caps 5 are fixed to the front and rear ends of the slider body 9 by bolts 12. The end caps 5 are, for example, injection-molded products made of synthetic resin, and are formed with a generally U-shaped cross section similar to the slider body 9. The end cap 5, together with a return guide (not shown), constitutes a direction change path of the unloaded rolling path 21.

[0019] 3 to 5, a plurality of steel balls (load bodies) 6 and a plurality of spacer balls (elastic bodies) 16 are filled in a rollable manner within a total of four rolling element rolling paths 23 provided inside the slider 2. These plurality of steel balls 6 and spacer balls 16 circulate endlessly while rolling within the rolling element rolling paths 23 as the guide rail 1 and slider 2 move relative to each other.

[0020] In this embodiment, in order to prevent the steel balls 6 from competing with each other in the unloaded rolling path, which would reduce the operability, and to suppress the steel balls 6 from pushing against each other due to elastic deformation, it is preferable that a plurality of rolling elements (a plurality of steel balls 6 and a plurality of spacer balls 16) are arranged without gaps. Therefore, as shown in FIG. 4, these plurality of rolling elements are arranged such that the number of steel balls 6 is M, the number of elastic bodies is N, the total number of these is L, and the gaps d between adjacent rolling elements are d. i When this is the case, they are arranged so as to satisfy the following formula 1.

[0021]

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[0022] Furthermore, in order to adjust the gap in the rolling element rolling path 23, it is preferable that the plurality of spacer balls 16 be configured with at least two or more types of spacer balls 16a, 16b having different diameters, as shown in Figures 3 to 5. The reason for using two or more types of spacer balls 16 with different diameters is that it is easier to adjust the gap in the rolling element rolling path 23 with two or more types than with one type.

[0023] Furthermore, in order to prevent the above-mentioned deterioration in operability, it is preferable that the total amount of deformation of the plurality of spacer balls 16 is 7% or less of the diameter of the steel ball 6. Therefore, as shown in FIG. 6, the spacer balls 16 are configured such that the amount of deformation on one side in the rolling direction is K j1 , the deformation amount on the other side of the rolling direction is K j2 When the diameter of the steel ball 6 is Da, the total amount of deformation is configured to satisfy the following formula 2.

[0024]

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[0025] Here, the deterioration of operability caused by the steel balls 6 competing with each other will be described in detail below.

[0026] The rolling element rolling path 23 is filled with only steel balls 6 as rolling elements. The unloaded rolling path 21 is a path for realizing infinite circulation of the steel balls 6, is formed larger than the diameter of the steel balls 6, and is composed of a combination of straight and curved sections. The loaded rolling path 22 is sandwiched between the rail-side raceway groove 3 and the slider-side raceway groove 7, and is a path along which the steel balls 6 are subjected to a preload load and an external load. In such a rolling element rolling path 23, the amount of movement changes between the steel balls 6 entering the unloaded rolling path 21 from the loaded rolling path 22 (entrance-side rolling elements) and the steel balls 6 exiting the unloaded rolling path 21 from the unloaded rolling path 21 (exit-side rolling elements). Hereinafter, this change in amount of movement will be referred to as the change in in / out amount.

[0027] Since the steel balls 6 in the unloaded rolling path 21 cannot move forward unless pushed by the steel balls 6 behind them, they are prone to clogging, which can lead to changes in the amount of steel balls 6 moving in and out. In other words, the amount of movement of the steel balls 6 leaving the unloaded rolling path 21 is smaller than the amount of movement of the steel balls 6 entering the unloaded rolling path 21, so clogging occurs in the unloaded rolling path 21 (partly because there is no gap to begin with). As a result, the steel balls 6 leaving the unloaded rolling path 21 slip due to the force generated by the clogging and enter the loaded rolling path 22, so the frictional force increases at that moment, resulting in poor operability.

[0028] Furthermore, even in the loaded rolling path 22, slight differences in speed occur among the steel balls 6 due to slight errors in the groove shape, etc. In this case, the faster steel balls will push the slower steel balls, and the steel balls 6 may compete with each other. As a result, just like in the unloaded rolling path 21, the steel balls 6 temporarily become difficult to turn, and the apparent frictional force between the slider 2 and the guide rail 1 momentarily increases.

[0029] Therefore, in this embodiment, in order to reduce the competition between the steel balls 6, absorb changes in frictional force, and not hinder the revolution of the steel balls 6, spacer balls 16 having a smaller elastic modulus and diameter than the steel balls 6 are placed in the rolling element rolling path 23.

[0030] In this embodiment, the rolling elements are configured to include a plurality of spacer balls 16 that have a smaller elastic modulus and diameter than the steel balls 6, thereby allowing slight changes in the amount of movement in and out to be absorbed by their elasticity. As a result, the movement of the steel balls 6 in the loaded rolling path 22 can be made smoother, resulting in a linear guide device with excellent operability. In other words, by being present together with the steel balls 6 in the unloaded rolling path 21 or the loaded rolling path 22, the spacer balls 16 function as a buffer against the steel balls competing with each other, resulting in good operability. Furthermore, by configuring the spacer balls 16 from at least two types of spacer balls 16a, 16b with different diameters, and by configuring the spacer balls 16 to satisfy the above formula 2, it is possible to appropriately adjust the gap in the rolling element rolling path 23. By eliminating the gap, it is possible to suppress positional deviation due to slippage of the steel balls 6, and thereby prevent deterioration of repeatable positioning accuracy.

[0031] In this embodiment, the material of the spacer balls 16 is not particularly limited, but it is preferable to select a material that is highly resistant to slippage and collisions (abrasion resistance), for example, a material with a surface Shore A hardness of between 40 and 95, and one selected from synthetic rubber (polyacetal, nitrile rubber, hydrogenated nitrile rubber, fluororubber, etc.) and thermoplastic elastomer. Spacer balls 16 made of such a material can be configured to have both elasticity and durability, and can be manufactured by injection molding, thereby reducing manufacturing costs.

[0032] Furthermore, in this embodiment, if the spacer balls 16 are larger than the steel balls 6, they will create resistance when moving from the unloaded rolling path 21 to the loaded rolling path 22, significantly reducing operability. Furthermore, if the diameter of the spacer balls 16 is 90% or more of the diameter of the loaded balls, the frictional force generated at the contact points between the rolling elements in the loaded rolling path can be reduced. Therefore, it is preferable that the diameter of the spacer balls 16 be 90% or more and 100% or less of the diameter of the steel balls 6.

[0033] In this embodiment, the number of spacer balls 16 is set to multiple (two or more). This ensures that at least one spacer ball is always present in the unloaded rolling path 21, thereby sufficiently absorbing the competition between the steel balls 6. On the other hand, if the number of spacer balls 16 becomes too large, the load capacity decreases, so it is preferable that the number of spacer balls 16 is smaller than the number of loaded balls.

[0034] Furthermore, in this embodiment, it is preferable that the plurality of spacer balls 16 are arranged at approximately equal intervals between the steel balls 6. This increases the probability that at least one spacer ball 16 is arranged in the unloaded rolling path and at least one spacer ball 16 is arranged in the loaded rolling path. As a result, friction between the steel balls can be suppressed even in the loaded rolling path, reducing jostling. Note that "substantially equal intervals" means that the number of steel balls present between adjacent spacer balls 16 is n or n+1 (n is any integer).

[0035] In this embodiment, the steel ball 6 is used as the load, but the load is not limited to a sphere and may be a roller, and is not limited to being made of metal but may be made of ceramic or the like.

[0036] As described above, the present specification discloses the following:

[0037] (1) a guide rail having a rail-side track groove on its side; a slider assembled to the guide rail and having a slider-side raceway groove facing the rail-side raceway groove; a plurality of rolling elements packed in a rolling element rolling path that is free to roll, the rolling element rolling path comprising a loaded rolling path formed by the rail-side raceway groove and the slider-side raceway groove, and an unloaded rolling path that is provided in the slider and connects one end of the loaded rolling path to the other end, A linear guide device in which one of the guide rail and the slider moves relative to the other as the rolling elements roll, The plurality of rolling elements are composed of a plurality of load elements and a plurality of elastic elements having a smaller elastic modulus and diameter than the load elements, and the number of the load elements is M, the number of the elastic elements is N, the total number of the rolling elements is L=M+N, and each gap between the adjacent rolling elements is d i When

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[0038] According to the configuration (1), the elastic body has a higher elastic modulus than the load body, so that the rolling elements can be arranged to satisfy equation (1), and the elastic body can be easily deformed, which reduces the competition between the steel balls. Therefore, this configuration provides excellent repeatability and excellent operability. Furthermore, this configuration makes assembly easy.

[0039] (2) The linear guide device according to (1), The plurality of elastic bodies are composed of at least two or more types of elastic bodies having different diameters. Linear guide device.

[0040] According to the configuration (2), the elastic body can further improve the effect of buffering the collision between the steel balls. Also, this configuration makes it easy to adjust the gap.

[0041] (3) The linear guide device according to (1) or (2), The deformation amount of the elastic body on one side in the rolling direction is K j1 , the deformation amount on the other side of the rolling direction of the elastic body is K j2 When the diameter of the elastic body is Da, the total deformation amount of the elastic body is

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[0042] According to the configuration (3), the elastic body can further improve its effect as a buffer against the collision of the steel balls.

[0043] (4) A linear guide device according to any one of (1) to (3), The rolling elements are spherical or roller shaped. Linear guide device.

[0044] According to the configuration (4), the present invention can be applied to a conventional linear guide device.

[0045] (5) A linear guide device according to any one of (1) to (4), The elastic body is made of one selected from synthetic rubber and thermoplastic elastomer. Linear guide device.

[0046] According to the configuration (5), the elastic body can be configured to have both elasticity and durability. [Explanation of symbols]

[0047] 1 Guide rail 2 Slider 3 Rail side track groove 6 Steel ball (load body) 7 Slider side raceway groove 9 Slider body 10 Linear guide device 16 Spacer ball (elastic body) 21 No-load rolling track 22 Load rolling path 23 Rolling body rolling path

Claims

1. a guide rail having a rail-side raceway groove on a side surface; a slider assembled to the guide rail and having a slider-side raceway groove facing the rail-side raceway groove; a plurality of rolling elements packed in a rolling element rolling path that is free to roll, the rolling element rolling path comprising a loaded rolling path formed by the rail-side raceway groove and the slider-side raceway groove, and an unloaded rolling path that is provided in the slider and connects one end of the loaded rolling path to the other end, A linear guide device in which one of the guide rail and the slider moves relative to the other as the rolling elements roll, The plurality of rolling elements are composed of a plurality of load elements and a plurality of elastic elements having a smaller elastic modulus and diameter than the load elements, and the number of the load elements is M, the number of the elastic elements is N, the total number of the rolling elements is L = M + N, and each gap between the adjacent rolling elements is d ｉ When [Equation 1] are arranged to satisfy Linear guide device.

2. 2. The linear guide device according to claim 1, The plurality of elastic bodies are composed of at least two or more types of elastic bodies having different diameters. Linear guide device.

3. 2. The linear guide device according to claim 1, The deformation amount of the elastic body on one side in the rolling direction is K ｊ１ , the deformation amount of the elastic body on the other side in the rolling direction is K ｊ２ When the diameter of the elastic body is Da, the total deformation amount of the elastic body is [Equation 2] fulfill, Linear guide device.

4. 2. The linear guide device according to claim 1, The rolling elements are spherical or roller shaped. Linear guide device.

5. 2. The linear guide device according to claim 1, The elastic body is made of one material selected from synthetic rubber and thermoplastic elastomer. Linear guide device.

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