Rolling guiding device

Abstract

This rolling guiding device comprises: a raceway member (200) having a rolling surface (202); and a moving member (300) that is movable along the raceway member (200) and has an endless circulation path (500) for a rolling element (400). The moving member (300) comprises: a body member (310) having a load rolling surface (311) and a non-load path (520) for the rolling element (400); and a pair of lids (320) having a turning path (530). The load rolling surface (311) has a rolling portion (312), and a pair of crowning portions (313) inclined from both ends of the rolling portion (312) toward the turning path (530). The load rolling surface (311) has a pair of chamfered portions (314) formed at both ends, each chamfered portion (314) having one end connected to the crowning portion (313) and the other end connected to the turning path (530) and being open on an end surface of the body member (310). Each chamfered portion (314) is inclined to the non-load path (520) side from a connection point with the crowning portion (313) in a curve in which the curvature changes continuously along the moving direction of the rolling element (400).

Description

Rolling guide device

[0001] The present invention relates to a rolling guide device.

[0002] A rolling guide device used in industrial machinery includes a track member on which a rolling surface for rolling elements is formed along the longitudinal direction, and a moving member that is assembled to the track member via a number of rolling elements that roll on the rolling surface and that is capable of reciprocating along the track member. The moving member has a loaded rolling surface on which the rolling elements roll while bearing a load, and the loaded rolling surface faces the rolling surface of the track member to form a loaded passage for the rolling elements. The moving member also includes a main body member that has an unloaded passage formed therein, which circulates the rolling elements from one end of the loaded passage to the other, and a pair of cover bodies that have direction change passages connecting the loaded passage and the unloaded passage. In the rolling guide device, the loaded passage and the unloaded passage are connected by a pair of direction change passages, forming an infinite circulation passage for the rolling elements. This allows the moving member to move along the track member without stroke restriction. Patent Document 1, etc., discloses such a rolling guide device.

[0003] Patent Document 1 discloses a linear guide unit having a track rail with a raceway groove formed along the longitudinal direction, and a slider with a raceway groove facing the raceway groove and sliding relative to the track rail via a plurality of rolling elements. The linear guide unit has a load path that receives a load together with the rolling elements via the raceway grooves of the slider and the track rail. The slider is formed with a direction change path and a return path that are unloaded paths along which the rolling elements circulate, following the load path. This allows the rolling guide device of Patent Document 1 to move the slider along the track rail without stroke restriction.

[0004] Patent Publication No. 2005-273765

[0005] In some rolling guide devices, a plurality of track members are connected in the longitudinal direction to form a path for the moving member. However, if the installation precision of each track member is low, a step may occur at the connection point between the track members. In this case, an impact may occur on the rolling surface of the rolling element, potentially causing the rolling surface to peel off. Therefore, there has been a demand for a rolling guide device that can sufficiently mitigate the impact of the rolling element moving from the direction change path to the load path, even when such a step occurs.

[0006] The present invention has been made in consideration of such problems, and its object is to provide a rolling guide device that can mitigate the impact on the rolling surface of the rolling element and ensure durability even when a step occurs at the connection point between the track members.

[0007] That is, the present invention provides a raceway member having a rolling surface along the longitudinal direction, and a moving member assembled to the raceway member via a number of rolling elements rolling on the rolling surface, movable along the raceway member, and having an infinite circulation path for the rolling elements, the moving element comprising a main body member having a loaded rolling surface opposing the rolling surface of the raceway member and constituting a loaded path for the rolling elements, and an unloaded path for the rolling elements parallel to the loaded path, and a direction change path for moving the rolling elements back and forth between the loaded path and the unloaded path, and attached to both end faces of the main body member in the moving direction. and a pair of cover bodies, and the loaded rolling surface formed on the main body member has a rolling section along which the rolling elements roll under load, and a pair of crowning sections inclined from both ends of the rolling section toward the direction change path, and at both ends of the loaded rolling surface, a pair of chamfered sections are formed, one end of which is connected to the crowning section and the other end of which is connected to the direction change path and is open to the end face of the main body member, and the chamfered sections are arranged so as to slope from the connection point with the crowning section toward the unloaded passage in a curve whose curvature changes continuously along the direction of movement of the rolling elements.

[0008] According to the rolling guide device of the present invention, the chamfered portion is provided in a curve whose curvature changes continuously along the direction of movement of the rolling elements, and is inclined from the connection point with the crowning portion toward the unload passage, so that the chamfered portion can be set deeper toward the unload passage from the rolling contact portion along which the rolling elements roll under load. Even if a step occurs at the connection point between the track members, the impact on the rolling surfaces of the rolling elements can be mitigated, and the durability of the product can be improved.

[0009] Fig. 1 is a perspective view of a rolling guide device according to one embodiment of the present invention. Fig. 2 is a cross-sectional view of a rolling guide device according to one embodiment of the present invention when observed from the cover side. Fig. 3 is a diagram showing an endless circulation path of a rolling guide device according to one embodiment of the present invention. Fig. 4 is an enlarged view showing a connection point between a load passage and a direction change path of a rolling guide device according to one embodiment of the present invention. Fig. 5 is an enlarged view showing a connection point between a load passage and a direction change path of a rolling guide device according to one embodiment of the present invention. Fig. 6 is a diagram showing a connection state between track members of a rolling guide device according to one embodiment of the present invention.

[0010] The rolling guide device of the present invention will be described in detail below with reference to the accompanying drawings.

[0011] 1 is a perspective view of a rolling guide device 100 according to one embodiment of the present invention. This rolling guide device 100 is composed of a linearly extending track member 200 and a moving member 300 attached to the track member 200 via a large number of balls as rolling elements. The rolling guide device 100 has the track member 200 installed on a fixed portion of various machinery and devices, and various movable bodies are mounted on the moving member 300, so that the movable bodies can be guided to reciprocate freely along the track member 200.

[0012] The track member 200 is formed as an elongated body with a substantially rectangular cross section, and two track members 200A, 200B are connected in the longitudinal direction. A plurality of bolt mounting holes 201 penetrating from the top surface to the bottom surface are formed in the track member 200 at predetermined intervals in the longitudinal direction. The rolling guide device 100 is designed to be able to firmly fix the track member 200 to the fixed part using fixing bolts inserted into these bolt mounting holes 201. Two rolling surfaces 202 for rolling elements are provided on each of the left and right side surfaces of the track member 200, and the track member 200 as a whole is provided with four rolling surfaces 202. The number of rolling surfaces 202 provided on the track member 200 can be changed as appropriate.

[0013] The moving member 300 is composed of a metal main body member 310 and a pair of lids 320 attached to both ends in the moving direction of the main body member 310. Mounting holes 330 for mounting the moving member 300 to the movable body are provided on the upper surface of the main body member 310. The moving member 300 is provided with a plurality of endless circulation paths for the rolling elements corresponding to each of the rolling surfaces 202 of the track member 200, and the moving member 300 shown in Figure 1 is provided with four endless circulation paths corresponding to the four rolling surfaces 202 provided on the track member 200.

[0014] FIG. 2 is a cross-sectional view showing the main body member 310 with the movable member 300 attached to the track member 200, and FIG. 3 is a cross-sectional view showing the endless circulation path 500 of the rolling elements 400. The main body member 310 has a base portion 310a on which the mounting surface of the movable element 300 is formed, and a pair of legs 310b perpendicular to the base portion 310a. The main body member 310 is disposed so as to straddle the track member 200, sandwiching the track member 200 between the pair of legs 310b. The base portion 310a is provided with a female thread used to integrally connect the main body member 310 and a pair of lid members 320. A load rolling surface 311 on which the rolling elements 400 roll is formed on the inner side of the leg portions 310b. The rolling surface 202 of the track member 200 and the loaded rolling surface 311 of the body member 310 face each other, forming a load passage 510 through which the rolling elements 400 roll while bearing a load between the body member 310 and the track member 200. The load passage 510 is set to be slightly smaller than the diameter of the rolling elements 400.

[0015] In each leg portion 310b, an unloaded passage 520 corresponding to each loaded rolling surface 311 is formed parallel to the loaded passage 510. The unloaded passage 520 is provided penetrating along the direction of travel of the main body member 310. The inner diameter of the unloaded passage 520 is set slightly larger than the diameter of the rolling elements 400. This allows the rolling elements 400 to move within the unloaded passage 520 without bearing any load.

[0016] The lid body 320, like the main body member 310, is formed with a U-shaped cross section having a base portion and a pair of legs perpendicular to the base portion. The lid body 320 is disposed so as to straddle the track member 200, sandwiching the track member 200 between the pair of legs. The lid body 320 is provided with a bolt mounting hole for mounting the lid body to the main body member 310. The lid body 320 and the main body member 310 can be integrally connected by inserting a bolt into the bolt mounting hole and screwing the bolt into a female thread provided on an end surface of the main body member 310.

[0017] The cover 320 has a direction change passage 530 formed by fitting the direction change portion 321. The direction change passage 530 is formed by the inner guide groove 322 of the direction change portion 321 facing the outer guide groove 323 of the cover 320. The direction change passage 530 is provided in each leg of the cover 320. The direction change passage 530 connects one end of the loaded passage 510 to one end of the unloaded passage 520, and can also connect the other end of the loaded passage 510 to the other end of the unloaded passage 520. As a result, the direction change passage 530 allows the rolling elements 400 to move back and forth between the loaded passage 510 and the unloaded passage 520.

[0018] 4 is an enlarged view showing the connection point between the load passage 510 and the direction change path 530. The load rolling surface 311 that constitutes the load passage 510 has a rolling guide portion 312 on which the rolling element 400 rolls under load, and a pair of crowning portions 313 that are inclined from both ends of the rolling guide portion 312 toward the direction change path 530. The rolling guide portion 312 is the location where the rolling element 400 rolls from one end of the load passage 510 to the other end when an external load acting on the moving member 300 is applied, and the load bearing capacity of the rolling guide device 100 is determined based on the overall length of the rolling guide portion 312. The rolling element 400a shown in FIG. 3 is rolling on the rolling guide portion 312 and is in a state where it is elastically deformed by the load applied to the moving member 300. Since the rolling guide device 100 has four endless circulation paths 500 , the load acting on the moving member 300 is borne by a plurality of rolling elements 400 rolling on the rolling surfaces 312 of each endless circulation path 500 .

[0019] The crowning portion 313 is formed continuously with the rolling guideway portion 312 and is smoothly connected to the rolling guideway portion 312 at a connection point P with the rolling guideway portion 312 by a curved surface without any corners. The crowning portion 313 is inclined from one end of the rolling guideway portion 312 toward the adjacent direction change path 530 in the direction of movement of the rolling element. Because the inclination direction of the crowning portion 313 is toward the loaded path 520, the path width of the crowning portion 313 gradually increases as it approaches the direction change path 530. The path width of the crowning portion 313 is set to be larger than that of the rolling guideway portion 312 and smaller than the diameter of the rolling element 400. Therefore, as shown in FIG. 5 , the crowning portion 313 is formed deeper toward the unloaded path 520 than the reference position a of the rolling guideway portion 312. In the following description, the rolling guideway portion 312 is defined as the reference position a, and the direction toward the unloaded path 520 is defined as the depth direction.

[0020] The rolling elements 400 rolling from the crowning portion 313 to the rolling guideway 312 move toward the region of the crowning portion 313 where the path width is narrow, and thus can gradually bear a load. That is, the rolling elements 400 can gradually bear a load from a state in which they bear no load before rolling into the crowning portion 313 to a state in which they bear a maximum load in the rolling guideway 312. Therefore, the crowning portion 313 can smooth the rolling of the rolling elements 400 on the rolling guideway 312, and can contribute to the smooth circulation of the rolling elements 400 within the endless circulation path 500.

[0021] Meanwhile, the rolling elements 400 moving from the crowning portion 313 toward the direction change path 530 move toward the region of the crowning portion 313 where the path width is larger, and thus the load on the rolling elements 400 is gradually released. That is, the load on the rolling elements 400 is gradually released from a state in which the rolling elements 400 are carrying a maximum load in the rolling path portion 312 until the rolling elements 400 pass through the crowning portion 313 and are released from the load. Therefore, the crowning portion 313 can smoothly discharge the rolling elements 400 from the rolling path portion 312, thereby contributing to the smooth circulation of the rolling elements 400 within the endless circulation path 500.

[0022] From the viewpoint of smooth circulation of the rolling elements 400 in the endless circulation path 500, it is preferable that the length A of the crowning portion 313 is set so that 2Da≦A≦3Da, where Da is the diameter of a single rolling element 400. Furthermore, although the crowning portion 313 shown in Fig. 4 has a linear shape in cross section, it may have a curved shape as long as it is possible to gradually apply or remove a load to the rolling elements 400 rolling in the load passage 510, thereby enabling the rolling elements 400 to roll smoothly relative to the rolling portion 312.

[0023] A pair of chamfered portions 314 that are open to the end face of the main body member 310 are provided at both ends of the load rolling surface 311. The chamfered portions 314 are formed into a curved shape by cutting a portion of the edge of a hole formed as the load passage 510. One end of the chamfered portion 314 is connected to the crowning portion 313, and the other end is connected to the inner circumferential guide groove 322 of the direction change portion 321. Therefore, the chamfered portion 314 is formed between the load rolling surface 311 and the direction change path 530. The chamfered portion 314 is formed continuously with the crowning portion 313, and the chamfered portion 314 and the crowning portion 313 are smoothly connected to each other at a connection point Q with a curved surface without any corners. Note that the sizes of the crowning portion 313 and the chamfered portion 314 in the drawings are exaggerated to facilitate understanding.

[0024] As shown by the dashed lines in Figures 4 and 5, the chamfered portion 314 is formed in a shape that resembles a portion of an ellipse. That is, the chamfered portion 314 is formed so as to slope toward the unloaded passage 520 along a curve whose curvature changes continuously along the direction of movement of the rolling element. More specifically, the chamfered portion 314 is formed with the greatest curvature at the connection point α between the chamfered portion 314 and the direction change passage 530. The curvature gradually decreases toward the connection point β between the chamfered portion 314 and the crowning portion 313, and is smallest at the connection point β. Therefore, the curvature of the chamfered portion 314 gradually becomes gentler toward the connection point β. The path width at the location where the chamfered portion 314 is formed is set slightly larger than the diameter of the rolling element 400, and the rolling element 400 is in an unloaded state. The curvature of the chamfered portion 314 in the direction of movement of the rolling element can be appropriately changed in design as long as the curvature of the connection point α is larger than the curvature of the connection point β.

[0025] In this embodiment, the depth c of the chamfered portion 314 is set to be at least twice the depth b of the crowning portion 313, i.e., 2b≦c. This enables the rolling guide device 100 to sufficiently mitigate the impact when the rolling element 400 comes into contact with the chamfered portion 314. Note that the depths of the chamfered portion 314 and the crowning portion 313 can be appropriately changed in design.

[0026] The shape of the chamfered portion 314 can be expressed by the following mathematical formula 1. In this mathematical formula 1, the denominator of the major axis of the ellipse of the chamfered portion 314 is the diameter Da of the rolling element, and the denominator of the minor axis is c-b.

[0027]

[0028] The chamfered portion 314 is formed at a position deeper toward the no-load passage than the position where the crowning portion 313 is formed (see FIG. 5). In this way, the chamfered portion 314 is formed in a curved shape between the crowning portion 313 and the direction change passage 530, and at a position deeper than the crowning portion 313 from the reference position a.

[0029] 6A is a diagram showing the track member 200A and the track member 200B as viewed from above, and FIG. 6B is a diagram showing the track member 200A and the track member 200B as viewed from the side. DY in FIG. 6A indicates the horizontal step between the track member 200A and the track member 200B, and DT in FIG. 6B indicates the vertical step between the track member 200A and the track member 200B. The chamfered portion 314 is formed larger than these step differences, and the size of the chamfered portion 314 is expressed by the following equation 2. In addition, when the horizontal step DY and the vertical step DT are small when the track member 200A and the track member 200B are connected, the rolling element 400 does not bear a load on the chamfered portion 314. However, when the horizontal step DY and the vertical step DT are large, the rolling element 400 moving on the chamfered portion 314 may bear a load.

[0030]

[0031] As a result, the rolling guide device 100 can ensure horizontal and vertical widths at the connection point between the load passage 510 and the direction change path 530. Therefore, the rolling guide device 100 can suppress the impact of contact with the chamfered portion 314 of the rolling element 400 passing through the connection point between the direction change path 530 and the load passage 510.

[0032] In the rolling guide device 100 of this embodiment, the chamfered portion 314 can be set deep from position a on the loaded rolling surface 311, so even if the track member 200A and the track member 200B are attached with low precision, the impact of the rolling elements 400 moving between the direction change path 530 and the loaded path 510 on the chamfered portion 314 can be alleviated, thereby improving the durability of the product. As a result, the rolling guide device 100 can achieve the effect of extending the product life.

[0033] Furthermore, in the rolling guide device 100, the depth C of the chamfered portion 314 is set to 2B≦C, so that the impact of the rolling element 400 on the chamfered portion 314 can be sufficiently alleviated.

[0034] While the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and improvements can be made to the above embodiments.

Claims

1. A bearing comprising: a raceway member (200) having a rolling surface (202) along the longitudinal direction; and a moving member (300) assembled to the raceway member (200) via a number of rolling elements (400) that roll on the rolling surface (202), movable along the raceway member (200), and having an endless circulation path (500) for the rolling elements (400), wherein the moving member (300) comprises: a main body member (310) having a loaded rolling surface (311) that faces the rolling surface (202) of the raceway member (200) and forms a loaded passage (510) for the rolling elements (400), and an unloaded passage (520) for the rolling elements (400) that is parallel to the loaded passage (510); a pair of lids (320) attached to both end faces of the main body member (310) in the direction of movement, the lids (320) having a direction change path (530) for moving the rolling elements (400) between the loaded path (510) and the unloaded path (520), the loaded rolling surface (311) formed on the main body member (310) having a rolling section (312) on which the rolling elements (400) roll under load, and a pair of crowning sections (313) inclined from both end portions of the rolling section (312) toward the direction change path (530), the loaded rolling surface (311) having a pair of chamfered sections (314) at both ends, one end of which is connected to the crowning section (313) and the other end of which is connected to the direction change path (530) and is open to the end face of the main body member (310), The rolling guide device (100) is characterized in that the chamfered portion (314) is a curve whose curvature changes continuously along the moving direction of the rolling element (400) and is provided so as to incline from the connection point with the crowning portion (313) toward the no-load passage (520).

2. The rolling guide device (100) according to claim 1, characterized in that the curvature of the chamfered portion (314) is set to be larger at the connection point between the chamfered portion (314) and the direction change path (530) than at the connection point between the chamfered portion (314) and the crowning portion (313).

3. The rolling guide device (100) according to claim 1, characterized in that the curvature of the chamfered portion (314) gradually decreases from the connection point between the chamfered portion (314) and the direction change path (530) toward the connection point between the chamfered portion (314) and the crowning portion (313).

4. The rolling guide device (100) according to claim 2, wherein the chamfered portion (314) is formed in a shape that resembles a part of an ellipse.

5. When the diameter of the rolling element (400) is Da, the depth of the crowning portion (313) is b, and the depth of the chamfered portion (314) is c, The rolling guide device (100) according to any one of claims 1 to 4, characterized in that it is formed so as to be 6. A rolling guide device (100) according to any one of claims 1 to 4, characterized in that the depth c of the chamfered portion (314) is set so that 2b≦c holds, where b is the depth of the crowning portion (313).

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