Direct-acting guide unit

Abstract

The direct-acting guide unit of the present invention includes a guide rail, a slider, and a plurality of rolling elements. The annular path in the direct-acting guide unit is composed of a track path, a first circulating path, and two second circulating paths serving as a connection between the track path and the first circulating path. The plurality of rolling elements circulate in the annular path. A first portion of the track path is formed at the boundary between the track path and the second circulating path. The contact angle θ1 between the rolling elements in the first portion of the track path and the second rolling surface in the slider is greater than the contact angle θ2 between the rolling elements outside the first portion of the track path and the second rolling surface. The slider includes: a housing; a pair of end caps configured to clamp the housing along the length of the guide rail; and a spacer disposed between at least one of the end caps and the housing, the spacer having a second rolling surface constituting the first portion of the track path.

Description

Technical Field

[0001] This invention relates to a direct-drive unit. This application claims priority to Japanese Patent Application No. 2020-180708, filed on October 28, 2020, and invokes all the contents described in that Japanese patent application. Background Technology

[0002] A known direct-acting guide unit comprises: a guide rail having a pair of first rolling surfaces; a slider having a pair of second rolling surfaces facing the pair of first rolling surfaces respectively; and a plurality of rolling elements configured to roll on the first rolling surfaces and the second rolling surfaces and circulate in an annular space (see, for example, Patent Document 1).

[0003] The circulation path of the rolling element consists of a track path, a first circulation path, and two second circulation paths. The track path is formed at the opposing portion of the guide rail and the slider. The first circulation path is formed parallel to the track path within the slider. The second circulation path is the connection point between the track path and the first circulation path. The slider includes a housing, a first circulation path component, and an end cap. It is known that a spacer is disposed between the housing and the end cap of the slider (see, for example, Patent Document 2).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-135981

[0005] Patent Document 2: Japanese Patent Application Publication No. 2003-90338 Summary of the Invention

[0006] Direct-acting guide units are used in various configurations, but their orientation can sometimes cause rolling elements to become clogged. Therefore, the aim is to provide a direct-acting guide unit that suppresses rolling element clogging regardless of its configuration.

[0007] According to the direct-drive unit disclosed herein

[0008] have:

[0009] The guide rail has a pair of first rolling surfaces that extend parallel to each other in the length direction;

[0010] A slider, movable relative to the guide rail, and having a pair of second rolling surfaces facing each of the first rolling surfaces; and

[0011] Multiple rolling elements are spheres that contact and roll with the first rolling surface and the second rolling surface.

[0012] In the direct-drive guiding unit, the loop path is composed of the following:

[0013] The track path is formed by the first rolling surface and the second rolling surface;

[0014] A first loop path, which runs parallel to the track path and is formed within the slider; and

[0015] Two second loop paths serve as the connection points between the track path and the first loop path.

[0016] The plurality of said rolling elements circulate in the circular path, wherein,

[0017] The boundary between the track path and the second loop path has a first section of the track path, and the contact angle θ1 between the rolling element and the second rolling surface in the first section of the track path is greater than the contact angle θ2 between the rolling element and the second rolling surface outside the first section of the track path.

[0018] The slider includes: a housing; a pair of end caps configured to clamp the housing along the length of the guide rail; and a spacer disposed between at least one of the pair of end caps and the housing.

[0019] The spacer has a second rolling surface that forms a first portion of the track path.

[0020] According to the above-mentioned direct-acting guide unit, regardless of how the direct-acting guide unit is configured, the blockage of the rolling elements is suppressed. Attached Figure Description

[0021] Figure 1 This is a perspective view showing the structure of the direct-drive guide unit in Embodiment 1.

[0022] Figure 2 This is a cross-sectional perspective view showing the structure of the direct-drive guide unit in Embodiment 1.

[0023] Figure 3 This is a perspective view showing the structure of the slider in Embodiment 1.

[0024] Figure 4 This is a perspective view showing the structure of the slider after the end seal and end cap in Embodiment 1 have been removed.

[0025] Figure 5 This is a rear view showing the structure of the end cap in Embodiment 1.

[0026] Figure 6 This is a perspective view showing the structure of the end cap in Embodiment 1.

[0027] Figure 7 This is a front view showing the structure of the spacer in Embodiment 1.

[0028] Figure 8 This is a rear view showing the structure of the spacer in Embodiment 1.

[0029] Figure 9 This is a perspective view showing the structure of the spacer in Embodiment 1.

[0030] Figure 10 This is a side view showing the structure of the spacer in Embodiment 1.

[0031] Figure 11 This is a perspective view showing the structure after the spacer and end cap are combined in Embodiment 1.

[0032] Figure 12 This is a schematic diagram showing a partial cross-section of the direct-drive guide unit of Embodiment 1, enlarged.

[0033] Figure 13 This is a schematic diagram showing the contact method between the wall and the rolling element in the second part of the track path in Embodiment 1.

[0034] Figure 14 This is a schematic diagram showing the contact method between the wall and the rolling element in the first part of the track path in Embodiment 1.

[0035] Explanation of reference numerals in the attached figures

[0036] 1. Direct-acting guide unit; 10. Guide rail; 12. First track groove; 13. Second track groove; 100. Slider; 101. Screw hole; 102. Track path; 102a. First part of track path; 102b. Second part of track path; 103. First circulation path; 104. Second circulation path; 110. Housing; 120. End cap; 121. Oil hole; 122. Oil groove; 123. Through hole; 124. Recess; 125. Outer peripheral wall of second circulation path; 126. Spoon nail; 127. End of outer peripheral wall of first circulation path; 128. Retaining band groove; 130. Spacer; 131. Spacer plate; 132. Inner peripheral wall of second circulation path; 133. Oil groove; 134. End of inner peripheral wall of first circulation path; 135. Insertion member; 136. Protrusion; 139. Leg; 140. End seal; 150. Retaining band; 151. Cylindrical member; 200. Ball bearing. Detailed Implementation

[0037] [Summary of Implementation Methods]

[0038] First, the embodiments of this disclosure will be described one by one. The linear guide unit of this disclosure includes: a guide rail having a pair of first rolling surfaces extending parallel to each other in the longitudinal direction; a slider straddling the guide rail and movable relative to it, and having a pair of second rolling surfaces facing the pair of first rolling surfaces respectively; and a plurality of rolling elements contacting the first rolling surfaces and the second rolling surfaces and rolling as balls. The linear guide unit of this disclosure is a linear guide unit in which the plurality of rolling elements circulate on a circular path, the circular path being composed of: a track path formed by the first rolling surfaces and the second rolling surfaces; a first circulating path parallel to the track path and formed within the slider; and two second circulating paths serving as connections between the track path and the first circulating path. In the linear guide unit of this disclosure, the boundary portion of the track path with the second circulation path has a first section of the track path, and the contact angle θ1 between the rolling element and the second rolling surface in the first section of the track path is greater than the contact angle θ2 between the rolling element and the second rolling surface outside the first section of the track path. In the linear guide unit of this disclosure, the slider includes: a housing; a pair of end caps configured to clamp the housing in the length direction of the guide rail; a spacer disposed between at least one of the pair of end caps and the housing; the spacer has a second rolling surface constituting the first section of the track path.

[0039] One configuration of the direct-acting guide unit involves setting the circulation paths on both sides of the guide rail in an vertically aligned manner. This configuration is known as a horizontal or lateral orientation. Previously, when the direct-acting guide unit was horizontally positioned, poor sliding of the slider sometimes occurred. Analysis of this poor sliding revealed the following as one cause: When the direct-acting guide unit is horizontally positioned, the track path and the first circulation path extend horizontally, while the second circulation path connecting them extends vertically. Therefore, rolling elements entering the second circulation path from the upper first circulation path fall into the second circulation path due to their own weight. If rolling elements, accelerated by their own weight, continuously fall into the track path, which is within the load range, the proper spacing between the rolling elements is lost. Consequently, the rolling elements compete with each other within the track path, resulting in blockage and poor sliding.

[0040] To address this problem, an investigation was conducted to suppress the competition between rolling elements along the track path, which serves as the load range. Furthermore, a travel adjustment section was conceived at the point where the rolling element enters the track path from the second circulation path, creating a speed difference with other rolling elements rolling on the track path. Further research revealed that by increasing the contact angle between the rolling element and the track path in the travel adjustment section, the orbital speed of the rolling element entering the track path from the second circulation path can be suppressed. With this structure, a speed difference was generated between existing rolling elements rolling on the track path and subsequent rolling elements, creating an appropriate gap between the rolling elements to suppress their competition.

[0041] According to the direct-acting guide unit of this disclosure, regardless of the orientation of the direct-acting guide unit, especially when the direct-acting guide unit is placed horizontally, poor sliding is not easily caused, thereby achieving smooth operation of the direct-acting guide unit. Furthermore, the direct-acting guide unit of this disclosure has a simple structure in which a portion is provided at the boundary between the track path and the second circulation path, such that the contact angle between the rolling element and the wall is greater than that of the rolling element and the wall in other parts of the track path. This allows for reliable modification of the revolution speed of the rolling element passing through this portion, and enables the generation of appropriate clearance between the rolling elements.

[0042] Additionally, in the linear guide unit of this disclosure, the slider includes: a housing; a pair of end caps configured to clamp the housing in the length direction of the guide rail; and a spacer disposed between at least one of the pair of end caps and the housing, the spacer having a second rolling surface constituting a first portion of the track path.

[0043] According to this structure, in the direct-drive guide unit, the insert member that constitutes the wall of the travel adjustment part, i.e. the first part of the track path, is assembled as part of the spacer. Therefore, the setting, adjustment, and modification of the travel adjustment part become easy, and it is excellent in terms of maintainability and manufacturing practicality.

[0044] In the direct-acting guide unit disclosed herein, the spacer may be a resin-molded component.

[0045] The guide rails and sliders of the direct-acting guide unit are mostly made of steel, but by making the spacers resin-molded components, it is easy to manufacture and ensures the required strength and durability.

[0046] In the direct-acting guide unit disclosed herein, the length of the first part of the track path in the longitudinal direction of the guide rail can also be more than 0.25 times and less than 3 times the diameter of the rolling element.

[0047] The length direction of the guide rail is the length direction of the first part of the track path. Furthermore, the length direction of the first part of the track path refers to the direction along the track of the rolling element. That is, the length of the first part of the track path is the length of the portion on the track with a contact angle different from the main area (the travel adjustment portion). In other words, the length of the first part of the track path is the length of the portion where the orbital speed of the rolling element changes (decreases). According to this disclosure, by providing an extremely short contact angle change portion of 0.25 times to 3 times the diameter of the rolling element in the annular path, smooth sliding of the direct-drive guide unit is achieved. According to this structure, the overall design of the direct-drive guide unit is minimized, and the occurrence of poor sliding is effectively suppressed.

[0048] In the direct-motion guide unit of this disclosure, in the first part of the track path, the rolling element and a portion of the wall surface of the first part of the track path of the spacer make contact at two points. Alternatively, the surfaces including the contact points can be planes extending along the length direction of the guide rail.

[0049] By making the contact point, including the contact point where the rolling element contacts the wall of the first part of the track path, a flat surface is provided, thereby simplifying the shape, making it easier to manufacture, and enabling the generation of spacers with minimal individual variations through a reasonable manufacturing process. In this disclosure, four travel adjustment portions (first part of the track path) are provided in a linear guide unit. By adopting this shape, the possibility of defects caused by individual variations in the travel adjustment portions can be reduced.

[0050] The contact angle θ1 in the first part of the track path can be set to be 1 to 20° larger than the contact angle θ2 in the track path outside the first part.

[0051] By setting the contact angle difference to a range of 1 to 20°, the rolling of the rolling elements can be adjusted and the spacing between the rolling elements can be maintained without hindering the movement of the rolling elements, thus enabling the smooth operation of the direct-drive unit.

[0052] [Specific examples of implementation methods]

[0053] Next, specific embodiments of the direct-acting guide unit of this disclosure will be described with reference to the accompanying drawings. In the following drawings, the same or equivalent parts are labeled with the same reference numerals, and their descriptions are omitted.

[0054] (Implementation Method 1)

[0055] Figure 1 This is a perspective view showing the structure of the direct-drive guide unit 1 in one embodiment of the present disclosure. Figure 1In the diagram, the X-axis direction is the width direction of the linear guide unit 1, the Y-axis direction is the length direction of the linear guide unit 1 (guide rail 10), and the Z-axis direction is the thickness direction of the linear guide unit 1. Figure 2 This indicates that the section is cut off at the center along the Z-axis. Figure 1 A cross-sectional view of the state after the direct-acting guide unit 1. Figure 3 This is a perspective view showing a portion of the slider 100 of the direct-acting guide unit 1.

[0056] Reference Figure 1 and Figure 2 The linear guide unit 1 includes a guide rail 10, a slider 100, and balls 200 as rolling elements. Multiple balls 200 as rolling elements are inserted into the linear guide unit 1. The linear guide unit 1 has an annular path, which is composed of: a track path 102 formed by the guide rail 10 and the slider 100 facing each other; a first circulation path 103 formed parallel to the track path 102 within the slider 100; and two second circulation paths 104 serving as the connection between the track path 102 and the first circulation path 103. In Embodiment 1, the length of the annular path is approximately 100 mm. Furthermore, the diameter of the balls 200 is 3 mm, and approximately 32 balls 200 are enclosed in the annular path. The length of the annular path, the size of the balls, and the number of balls are not limited; for example, the annular path can be approximately 20 to 1000 mm long, and approximately 10 to 60 balls with a diameter of approximately 0.4 to 13 mm can be used as the balls (rolling elements).

[0057] Reference Figure 1 Mounting holes 11 are formed on the guide rail 10 for fixing and mounting the mating components of the direct-drive guide unit 1. First track grooves 12 are formed on both sides of the guide rail 10 along its length. The wall surface of the first track groove 12 is a first rolling surface. The first track groove 12 is a pair of grooves formed on both sides of the guide rail 10 along its length. The concave shape of the first track groove 12 is uniform and covers the entire length of the guide rail 10. That is, the shape and angle of the sidewalls constituting the first track groove 12, and the depth of the groove, are constant along the entire length of the first track groove 12.

[0058] The slider 100 is mounted across the guide rail 10. The guide rail 10 and the slider 100 slide freely relative to each other. The slider 100 has a housing 110, end caps 120 mounted on both ends of the housing 110 in the longitudinal direction, a spacer 130 inserted between the housing 110 and the end caps 120, and an end seal 140 mounted on the outer end face of the end caps 120.

[0059] Figure 3 This diagram shows the state after the end seal 140 on one side of the slider 100 has been removed. (Refer to...) Figure 2 and Figure 3The slider 100 consists of an upper part and a sleeve hanging down from the side of the upper part. Multiple holes 101 are formed in the upper part of the slider 100 as mounting screw holes for mounting mating components such as workpieces and equipment. A first circulation path 103 and a second circulation path 104, continuous at both ends of the first circulation path 103, are formed inside the sleeve of the slider 100. Furthermore, a second track groove 13 is formed on the facing surface of the slider 100 opposite to the guide rail 10. The wall surface of the second track groove 13 is a second rolling surface. The first track groove 12 of the guide rail 10 and the second track groove 13 of the slider 100 face each other, and a track path 102 is formed between them. The conduit formed by the first track groove 12 of the guide rail 10 and the second track groove 13 of the slider 100 facing each other is the main area of ​​the track path 102, namely the second part 102b of the track path. Figure 12 The track path 102 and the first circulation path 103 are both straight pipes along the length of the guide rail 10. On the other hand, the second circulation path 104 is an arc-shaped pipe connecting them. The track path 102, the first circulation path 103, and the second circulation path 104 forming an endless loop path are formed. The direct-acting guide unit 1 is an infinitely looping direct-acting guide unit in which ball bearings 200 enclosed in the loop path circulate infinitely.

[0060] When the slider 100 moves on the guide rail 10, it slides on the guide rail 10 due to the rolling of the ball bearing 200. A through hole 123 is formed in the end cap 120, and a fixing bolt for fixing the end cap 120 together with the end seal 140 and the spacer 130 to the housing 110 is inserted into the through hole 123. A retaining band groove 128 is formed on the front side of the end cap 120 (the side facing the end seal 140). Retaining band 150 ( Figure 12 The belt is designed to prevent the balls 200 from falling off when the slider 100 is removed from the guide rail 10.

[0061] Figure 4 This diagram shows the state after the end cap 120 and end seal 140 have been removed from the slider 100, exposing the spacer 130 on one side. The spacer 130 is positioned along the length of the slider 100, contacting both end faces of the housing 110 in a manner that clamps the housing 110. (Refer to...) Figure 4The spacer 130 generally includes a spacer plate 131 located above and extending along the entire width of the slider 100, and a leg 139 located below the spacer plate 131 and forming part of an annular path. The leg 139 of the spacer 130 includes the wall surface of the second circulation path 104, namely the inner peripheral wall 132 of the second circulation path. Furthermore, the leg 139 of the spacer 130 includes an insertion member 135 located at the boundary between the second circulation path 104 and the track path 102. The insertion member 135 is integrally formed with the spacer 130. The insertion member 135 forms part of the second rolling surface of the track path 102. When the guide rail 10 and the slider 100 are combined, the insertion member 135 faces the first track groove 12 of the guide rail 10, and the track path 102 is formed between them. The conduit formed by the insertion member 135 facing the first track groove 12 of the guide rail 10 is the first part 102a of the track path. Figure 12 The first part 102a of the track path is a portion of the track path 102 at the boundary between the track path 102 and the second loop path 104. The inner circumferential surface of the insertion member 135 is continuous with the second track groove 13, forming the second rolling surface of the track path 102.

[0062] A through hole 123 is formed on the spacer plate 131. The through hole 123 is for connecting the spacer 130 to the end cap 120 and the end seal 140. Figure 1 The spacer 130 is fixed to the housing 110 together with the hole into which the fixing bolt is inserted. A protrusion 136 is formed on the upper part of the inner peripheral wall 132 of the second circulation path. The protrusion 136 allows for easy positioning when the spacer 130 and the end cap 120 are assembled.

[0063] Figure 5 This indicates the back side of the end cap 120 (the side facing the spacer 130). Figure 6 This is a 3D view of the back of end cap 120. (Refer to...) Figure 5 and Figure 6 An oil groove 122 is formed on the end cap 120, which connects the oil hole 121 and the oil groove 122. Lubricant injected from the grease inlet provided on the end seal 140 can be supplied into the annular path through the oil hole 121 and the oil groove 122.

[0064] End cap 120 has a second circulation path outer peripheral wall 125. The second circulation path outer peripheral wall 125 and the second circulation path inner peripheral wall 132 of spacer 130 ( Figure 4 The two paths face each other, forming a direction-changing path 104. A positioning recess 124 is formed on the upper part of the outer peripheral wall 125 of the second circulation path. The recess 124 is opposite to the protrusion 136 of the spacer 130. Figure 4 The shape of the fitting. When the recess 124 and the protrusion 136 of the spacer 130 are joined. Figure 4When the end cap 120 and the spacer 130 are combined, a second circulation path 104, which is an arc-shaped route, is formed. The outer peripheral wall 125 of the second circulation path has a protruding spoon-shaped prong 126 at its inner end (the end continuous with the track path 102) along the direction of the track path 102. The spoon-shaped prong 126 connects with the first track groove 12 of the guide rail 10. Figure 1 The ball bearing 200 enters the second circulation path 104 from the track path 102 via the spoon nail 126. At the outer end of the outer peripheral wall 125 of the second circulation path, a first circulation path outer peripheral wall end 127, which constitutes part of the outer peripheral wall of the first circulation path 103, is continuously provided with the outer peripheral wall 125 of the second circulation path.

[0065] Figure 7 This indicates the front side of the spacer 130 (the side facing the end cap 120). Figure 8 This indicates the back side of the spacer 130 (the side facing the housing 110). Figure 9 This is a three-dimensional view of spacer 130. Figure 10 This indicates the side of spacer 130. (See reference) Figure 7 and Figure 9 and Figure 10 On the front side of the spacer 130, the inner peripheral wall 132 of the second circulation path in the leg 139 and the protrusion 136 are provided in a manner that protrudes outward from the spacer plate 131. An oil groove 133 is provided at the center of the protrusion 136.

[0066] Reference Figures 8-10 An insertion member 135, forming part of the inner peripheral wall of the track path 102 in the leg 139, and a first circulation path inner peripheral wall end 134, forming part of the inner peripheral wall of the first circulation path 103, are provided on the back side of the spacer 130. The insertion member 135 and the first circulation path inner peripheral wall end 134 are provided on the back side of the spacer 130 in a manner that protrudes outward from the spacer plate 131. The insertion member 135 and the first circulation path inner peripheral wall end 134 are connected to the first track groove 12 of the guide rail 10. Figure 1 The first part of the orbital path 102a is formed by the two opposing forces. Figure 12 The end 134 of the inner peripheral wall of the first circulation path is continuous with the inner peripheral wall 132 of the second circulation path. When the spacer 130 and the end cap 120 are connected... Figure 6 When combined, the end 134 of the inner peripheral wall of the first circulation path and the end 127 of the outer peripheral wall of the first circulation path of the end cap 120 are... Figure 6 They face each other and form the ends of the first loop path 103.

[0067] Figure 11The diagram shows the combined state of the end cap 120 and the spacer 130. The end 134 of the inner peripheral wall of the first circulation path of the spacer 130 faces the end 127 of the outer peripheral wall of the first circulation path of the end cap 120 to form the end of the first circulation path 103. The connection between the inner peripheral wall 132 of the second circulation path 104 and the insertion member 135, which forms part of the inner peripheral wall of the track path 102, is a slight step because the shapes of the inner peripheral wall 132 and the wall of the insertion member 135 are different from each other.

[0068] Figure 12 yes Figure 2 A partially enlarged cross-sectional view of the shown direct-acting guide unit 1. (Refer to...) Figure 12 The guide rail 10 and the slider 100 are combined together. When the slider 100 moves due to external force, the ball bearing 200 contacts the wall of the first track groove 12. The guide rail 10 and the slider 100 slide by rolling the ball bearing 200.

[0069] In the slider 100, the wall of the main region of the first circulation path 103 is formed by a cylindrical member 151 extending along the length of the first circulation path 103. At the end of the first circulation path 103 (the boundary between the first circulation path 103 and the second circulation path 104), the end 134 of the inner peripheral wall of the spacer 130 faces the end 127 of the outer peripheral wall of the end cap 120. In addition, the inner peripheral wall 132 of the second circulation path and the outer peripheral wall 125 of the second circulation path face each other to form an arc-shaped second circulation path 104.

[0070] The track path 102 includes a first portion 102a of the track path formed by the first track groove 12 of the guide rail 10 and the insertion member 135 of the slider 100 facing each other, and a second portion 102b of the track path formed by the first track groove 12 of the guide rail 10 and the second track groove 13 of the slider 100 facing each other. The first portion 102a of the track path is located at the boundary between the track path 102 and the second loop path 104.

[0071] Reference Figure 12 In the first circulation path 103 and the second circulation path 104, which are in an unloaded range, the ball bearings 200 roll freely. The cylindrical member 151 of the first circulation path 103 is a lubricating component, and the ball bearings 200 roll while being lubricated. On the other hand, in the track path 102, which is in a loaded range, the ball bearings 200 rotate and revolve while abutting against the wall of the track path 102 (the surfaces of the first track groove 12 and the insertion member 135 in the first part 102a of the track path, and the surfaces of the first track groove 12 and the second track groove 13 in the second part 102b of the track path).

[0072] Reference Figure 12The operation of the direct-acting guide unit 1 will be explained. In the direct-acting guide unit 1, the guide rail 10 is fixed, and the slider 100 is moved along the guide rail 10 by an external force. For example, when the slider 100 moves to the right ( Figure 12 As the ball 200 moves (to the right of the paper), it rotates on its own axis while also revolving clockwise. That is, the ball 200 travels from the first loop path 103 through the second loop path 104 to the track path 102. An insertion member 135 is present at the boundary between the second loop path 104 and the track path 102, i.e., the first part 102a of the track path. Therefore, the ball 200 entering the track path 102 from the second loop path 104 first passes through the insertion member 135 (the first part 102a of the track path) on the track path 102, and then enters the second part 102b of the track path formed by the first track groove 12 and the second track groove 13.

[0073] Figure 13 express Figure 12 Section AA′ in the diagram is the section within the second part 102b of the track path. (Refer to...) Figure 13 The ball bearing 200 is held between the guide rail 10 and the slider 100. The ball bearing 200 contacts the guide rail 10 at two contact points p3 on the surface of the first track groove 12 of the guide rail 10. The contact angle θ3 is 50°. The contact angle θ3 is the angle formed by the line L extending horizontally through the center of the ball bearing 200 and the line L3 passing through the center of the ball bearing 200 and the contact point p3. Additionally, the second track groove 13 in the slider 100 has a Gothic arch shape in its cross-section orthogonal to its length direction, i.e., a Gothic arch groove. The ball bearing 200 abuts against the second track groove 13 (second rolling surface) of the slider 100 at two contact points p2. This contact angle θ2 is 50°. The contact angle θ2 is the angle formed by the line L extending horizontally through the center of the ball bearing 200 and the line L2 passing through the center of the ball bearing 200 and the contact point p2.

[0074] Figure 14 express Figure 12The BB′ section is shown in the diagram. The ball 200 is held between the guide rail 10 and the insertion member 135. The ball 200 contacts the guide rail 10 at two contact points p3 on the surface of the first track groove 12 of the guide rail 10. The contact angle θ3 is 50°. The contact angle θ3 is the angle formed by a line L extending horizontally through the center of the ball 200 and a line L3 passing through the center of the ball 200 and the contact point p3. An insertion member 135 is provided on the slider 100, and the ball 200 contacts the insertion member 135 at two contact points p1 on the surface (second rolling surface) of the insertion member 135. The contact angle θ1 between the ball 200 and the insertion member 135 is 60°. The contact angle θ1 is the angle formed by a line L extending horizontally through the center of the ball 200 and a line L1 passing through the center of the ball 200 and the contact point p1. The contact angle θ1 is the same along the entire length of the insertion member 135 (i.e., along the entire length of the first portion 102a of the track path). Furthermore, in Embodiment 1, as described above, the contact angle θ1 is the same along the entire length of the first portion 102a of the track path, but the contact angle can also be varied within the first portion of the track path.

[0075] On a cross section orthogonal to the length direction of the insertion member 135, the wall surface including the contact point p1 is a plane. That is, in the first part 102a of the track path, the inner wall surface of the insertion member 135 (the wall surface facing the ball 200) includes: two planes m 11 m 12 The contact points p1 of the two points are their respective contact surfaces and extend along the length direction of the track path 102; and the curved surface m 13 Connect two planes m 11 m 12 In implementation method 1, the curved surface m 13 It is a surface with constant curvature on its cross-section, but if it connects two planes m 11 m 12 A face can be a single face or a combination of multiple faces.

[0076] Reference Figure 13 and Figure 14In track path 102, the contact angle θ1 between the ball bearing 200 and the track path wall in the section where the insertion member 135 is located (track path first section 102a) is greater than the contact angle θ2 between the ball bearing 200 and the track path wall in other sections of track path 102 (track path second section 102b). Here, a larger contact angle between the ball bearing and the track path results in a smaller radius of rotation for the ball bearing and a slower orbital speed. Therefore, the ball bearing 200 entering track path 102 from the second circulation path 104 orbits at a slower speed in track path first section 102a than the existing ball bearing that entered track path 102 earlier. Thus, by creating an appropriate gap between the balls within track path 102, the mutual competition between the balls can be suppressed.

[0077] In embodiment 1, the contact angle θ1 is 10° larger than the contact angle θ2, but the difference in contact angles is not limited to this. For example, it can be set to about 1 to 20°, and the difference in contact angles is preferably 5 to 15°. If the difference in contact angles is about 1 to 20°, the rolling of the rolling elements can be adjusted to maintain the distance between the rolling elements and does not hinder the rolling of the rolling elements.

[0078] The length of the insertion member 135 in the track direction (i.e., the length of the first portion 102a of the track path) is not particularly limited, as long as the inventive effect can be achieved. For example, it can be set to be more than 0.25 times and less than 3 times the diameter of the rolling element 200. If the length of the first portion 102a of the track path is more than 0.25 times the diameter of the rolling element, the effect of suppressing the mutual competition of the rolling elements can be obtained by adjusting the movement of the rolling elements. In addition, since the rolling element located in the second portion 102b of the track path preferably bears the load, it is preferable that the length of the second portion 102b of the track path is longer (i.e., the length of the first portion 102a of the track path is shorter) so that the number of rolling elements located in the second portion 102b of the track path can be increased. Therefore, the length of the first portion 102a of the track path is preferably less than 3 times the diameter of the rolling element. In addition, the specific length of the insertion member 135 in the track direction is not particularly limited, and is selected according to the overall size of the direct-drive guide unit 1, etc. For example, it can be set to about 0.5 to 5 mm, preferably 2 to 4 mm. In addition, the insertion member 135 can be formed of resin, for example. When the insert member 135 is formed from resin, the design freedom is increased compared to the case where it is formed from steel. In addition, by forming it integrally with the spacer, the insert member can be easily and reliably arranged in the track path.

[0079] (Example)

[0080] A direct-drive guide unit as shown in Embodiment 1 was fabricated, placed horizontally, and operated. The revolution speed of the rolling elements 200 in the first portion 102a and the second portion 102b of the track path was measured. As a result, the first portion 102a of the track path was slower than the second portion 102b of the track path, confirming that a gap was generated between the rolling elements in the second portion 102b of the track path.

[0081] The embodiments disclosed herein are merely illustrative in all respects and should be understood as not being limited in any way. The scope of the invention is not limited to the foregoing description, but is defined by the claims, and is intended to include all modifications equivalent to the meaning and scope of the claims.

Claims

1. A direct-acting guide unit, have: The guide rail has a pair of first rolling surfaces that extend parallel to each other in the length direction; The slider is movable across the guide rail and has a pair of second rolling surfaces facing each of the pair of first rolling surfaces. as well as Multiple rolling elements are spheres that contact and roll with the first rolling surface and the second rolling surface. In the direct-drive guiding unit, the loop path is composed of the following: The track path is formed by the first rolling surface and the second rolling surface; The first loop path is parallel to the track path and is formed within the slider; as well as Two second loop paths serve as the connection points between the track path and the first loop path. The plurality of said rolling elements circulate in the circular path, wherein, The boundary between the track path and the second loop path has a first section of the track path, and the contact angle θ1 between the rolling element and the second rolling surface in the first section of the track path is greater than the contact angle θ2 between the rolling element and the second rolling surface outside the first section of the track path. The slider includes: a housing; a pair of end caps configured to clamp the housing along the length of the guide rail; and a spacer disposed between at least one of the pair of end caps and the housing. The spacer has a second rolling surface that forms a first portion of the track path.

2. The direct-acting guide unit as described in claim 1, wherein, The spacer is a resin-molded component.

3. The direct-acting guide unit as described in claim 1 or 2, wherein, The length of the first portion of the track path in the longitudinal direction of the guide rail is more than 0.25 times and less than 3 times the diameter of the rolling element.

4. The direct-acting guide unit as described in claim 3, wherein, In the first part of the track path, the rolling element contacts the second rolling surface at two points, and the surfaces including the contact points are planes extending along the length direction of the guide rail.

5. The direct-acting guide unit as described in claim 1 or 2, wherein, In the first part of the track path, the rolling element contacts the second rolling surface at two points, and the surfaces including the contact points are planes extending along the length direction of the guide rail.

6. The direct-acting guide unit as described in claim 1 or 2, wherein, The contact angle θ1 is 1 to 20° larger than the contact angle θ2.

7. The direct-acting guide unit as claimed in claim 3, wherein, The contact angle θ1 is 1 to 20° larger than the contact angle θ2.

8. The direct-acting guide unit as claimed in claim 4, wherein, The contact angle θ1 is 1 to 20° larger than the contact angle θ2.

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