Track element of a rolling guide device

Abstract

Track element (1) of a rolling guide device, with a plurality of heat pipes (7), wherein the heat pipes (7) are arranged in at least two rows along a longitudinal direction of the track element (1), wherein in each row a plurality of heat pipes (7) are arranged at intervals along the longitudinal direction of the track element (1), each heat pipe (7) having two ends, and wherein a respective end of both ends of the same heat pipe (7) in a row is arranged so as to overlap a respective other heat pipe from the group of two heat pipes (7) arranged in another row in a width direction of the track element (1), and wherein one of the ends of a corresponding heat pipe (7) of the plurality of heat pipes (7) positioned at an end portion of the track element (1) in the longitudinal direction protrudes from the track element (1), and a cooling device or a heating device is connected to the projecting end of the heat pipe (7).

Description

TECHNICAL FIELD

[0001] The present invention relates to a track member configured to guide a moving block along a linear path or an arc path in a rolling guide device used on a linear guide portion or a curved guide portion of machine tools or various industrial robots. STATE OF THE ART

[0002] Heretofore, as a rolling guide device serving as a guide portion of machine tools or various industrial robots, a rolling guide device has been known that includes a track member having a linear shape or an arc shape and a ball raceway surface along a longitudinal direction, and a moving block mounted on the track member through the intermediary of a large number of balls. The moving block has a load raceway surface opposed to the ball raceway surface of the raceway member and includes a circulation path for endlessly circulating the large number of balls rolling while bearing a load between the load raceway surface and the raceway surface of the track member. By circulating the balls in the endless circulation path, the moving block can move freely along an entire length of the track member.

[0003] Typically, the track element is fixed to a fixed portion, such as a bed or column of a machine tool, by fastening bolts. Generally, the track element is made of carbon steel to allow the rolling surface to be quenched. However, the material of the fixed portion may vary depending on the application of the rolling guide device. Thus, the thermal expansion coefficients of the track element and the fixed portion differ from each other. In recent years, there has been a case where fiber-reinforced plastic is used for the fixed portion, and the thermal expansion coefficient of the fixed portion can be significantly smaller than that of the track element.Therefore, if a temperature change occurs after the track element is attached to the fixed portion, depending on the difference in the thermal expansion coefficient, the expansion / contraction amount of the track element and the expansion / contraction amount of the fixed portion may differ significantly. As a result, there is a risk of inducing deformation of the track element, and the driving accuracy of the moving block may be affected.

[0004] Patent Literature 1 discloses a rolling guide device that actively controls the temperature change of the track element to prevent deformation of the track element. In this rolling guide device, a flow passage for a heat medium is provided along an entire length of the track element in a longitudinal direction, and a cooler configured to circulate the heat medium is connected to the flow passage.

[0005] Further relevant prior art is disclosed in the following documents: JP 2015 - 175 422 A, JP 2 632 445 B2, JP 2004 - 92 764 A and WO 2005 / 077 597 A1. CITATION LISTPATENT LITERATURE

[0006] [PTL 1] JP 2015-175422 A DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In general, a heat pipe is known as a mechanism for efficiently performing heat transfer, such as cooling or heating an object. Considering the more efficient implementation of temperature control of the trace element, it is conceivable to use the heat pipe instead of the flow channel for the heat medium.

[0008] However, the heat pipe is limited in a manufacturable length due to its internal structure, and it is difficult to provide a heat pipe along the entire length of a long conductor element of several meters. MEANS TO SOLVE THE PROBLEMS

[0009] The present invention has been made in view of such problems and has an object to provide a track member of a rolling guide device capable of efficiently performing temperature control of cooling or heating by using a heat pipe and capable of reliably performing the temperature control even when a long heat pipe of several meters is used.

[0010] To solve the problem described above, a track element is provided according to claim 1. Furthermore, a fastening plate is provided according to the independent claim 4. Further advantageous embodiments are defined in the dependent claims. EFFECTS OF THE INVENTION

[0011] According to the present invention, the track element comprises heat pipes arranged in at least two rows along the longitudinal direction of the track element, and both ends of a heat pipe belonging to any one of the rows are arranged to overlap two different heat pipes belonging to another of the rows in the width direction of the track element. Thus, heat transfer from the heat pipe belonging to any one of the rows to the heat pipes belonging to another of the rows is easily performed. Therefore, even though a plurality of short heat pipes are used in combination, the temperature of the entire track element can be easily adjusted to be uniform. In addition, if a cooling device or a heating device is connected to the heat pipe protruding from one end portion of the track element in the longitudinal direction, the temperature of the track element can be appropriately controlled. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1 is a perspective view illustrating a track member of a rolling guide device according to a first embodiment of the present invention. Fig. 2 is a bottom view of the track element according to the first embodiment. Fig. 3 is a sectional view along the line III-III of Fig. 2. Fig. 4 is a bottom view of a track element fixing plate according to a second embodiment of the present invention. Fig. Figure 5 is a sectional view taken along line VV of Figure 5.4. MODE FOR CARRYING OUT THE INVENTION

[0012] Now, a detailed description will be given of a track member of a rolling guide device according to an embodiment of the present invention with reference to the accompanying drawings.

[0013] Fig. 1 is a diagram of a track member according to a first embodiment of the present invention. The track member 1 is linearly formed, and a moving block 2, which is freely movable along the track member 1, is mounted on the track member 1 through the intermediary of a large number of balls 3, which are rolling elements. The track member 1 is installed on a fixed portion such as a bed or a column, and a moving block of various types is arranged on the moving block 2. Thus, the movable body can be guided reciprocally along the track member 1.

[0014] The track member 1 is formed into an elongated body with a substantially rectangular cross-sectional shape. The track member 1 has a plurality of bolt fastening holes 12 extending from an upper surface to a lower surface at predetermined intervals in the longitudinal direction. By using fastening bolts inserted into these bolt fastening holes 12, the track member 1 can be firmly attached to the fixed portion such as a bed or a pillar. Projecting portions are formed on both the right and left side surfaces of the track member 1 along the longitudinal direction, and a rolling surface 11 for the balls 3 is formed on an upper side and a lower side of each projecting portion. Four rolling surfaces 11 are formed on the entirety of the track member 1.The number of rolling surfaces 11 formed on the track member 1 is not limited to four, and the rolling elements may be rollers instead of the balls.

[0015] The moving block 2 mainly includes a metal block main body 21 and a pair of resin end plates 22 mounted at both ends of the block main body 21 in a moving direction. The moving block 2 has a plurality of endless circulation paths for the balls 3, which are formed to correspond to the rolling surfaces 11 of the track member. The endless circulation paths are completed by attaching the pair of end plates to the two ends of the moving block 2. A flexible retaining band 30 is incorporated into each of the endless circulation paths, and a large number of balls 3 are arranged in a row in the retaining band 30. Thus, when the moving block 2 is moved in the longitudinal direction of the track member 1 and the balls 3 roll on the rolling surfaces of the track member 1, the retaining band 30 circulates together with the balls 3 in each of the endless circulation paths.

[0016] The shape and structure of the movement block 2, which is in Fig. 1 is merely an example of the rolling guide device to which the present invention is applicable, and the present invention is not limited to the features including the presence or absence of the endless circulation paths for the rolling elements. Furthermore, only the balls 3, which are rolling elements, may be arranged in each of the endless circulation paths without using the tether 30.

[0017] In addition, various sealing elements 4, 5, and 6, configured to seal gaps between the moving block and the track element, are attached to the moving block. This prevents dust adhering to the track element 1 from entering the endless circulation paths. Fig. 1, for the sake of simplicity, the presence of the balls 3 and the retaining bands 30 in the endless circulation paths is shown, showing a state in which a quarter of the entire moving block 2 is cut out.

[0018] The track element 1 has heat pipes which are provided so that they extend along the longitudinal direction of the track element 1. As shown in Fig. As shown in Figure 1, end portions of heat pipes 7 protrude from end portions of the track element 1 in the longitudinal direction. Although not shown, for example, a heat sink, which is a cooling device, or a heater, which is a heating device, is connected to a protruding end of the heat pipe 7. The heat of the track element 1 can be transferred to the outside through the heat pipe 7, or heat can be transferred from the outside to the track element 1 through the heat pipe 7. Thus, the temperature of the track element 1 is managed.

[0019] Fig. 2 is a bottom view of the track element 1 in contact with the fixed section, and Fig. Figure 3 is a sectional view of the track element 1 taken along a plane orthogonal to the longitudinal direction. Due to its structure, it is generally difficult to manufacture a heat pipe with a total length of several meters. Even if such a heat pipe can be manufactured, the manufacturing cost is high. In contrast, the track element can have a total length of several meters, while the total length of the track element varies depending on the application.

[0020] Therefore, according to the present invention, the plurality of heat pipes 7 are arranged at constant intervals along the longitudinal direction of the track member 1. Moreover, the heat pipes 7 are not arranged in one row with respect to the track member 1, but are arranged in two rows so that they are arranged on both sides of the bolt fastening holes 12 in a width direction of the track member 1. The heat pipe 7 in one of the rows does not completely overlap the heat pipe 7 in another of the rows in the width direction of the track member and differs in position in the longitudinal direction of the track member.

[0021] In Fig. 2, the entire length of the track element 1 is not shown, and only a predetermined length from one end in the longitudinal direction is shown. In Fig. 2, an end portion of a heat pipe 7a protruding from one end of the track member overlaps an end portion of a heat pipe 7b in the width direction of the track member. Furthermore, another end portion of the heat pipe 7b overlaps an end portion of another heat pipe 7c in the width direction of the track member. Furthermore, end portions of the heat pipe 7a and the heat pipe 7b positioned on a side surface of the track member are not in contact with each other but are arranged at a constant distance. That is, the plurality of heat pipes 7a, 7b, and 7c are arranged in a staggered pattern in two rows along the longitudinal direction of the track member 1, and this arrangement is repeated over the entire length of the track member 1. In the first embodiment, the heat pipes 7 are arranged in two rows with respect to the track member 1.However, the heat pipes 7 may be arranged in a staggered pattern in three or more rows, depending, for example, on the size of the track element 1.

[0022] In addition, in the Fig. 2, the end portions of the heat pipes 7 are bent in the width direction toward the center of the track element 1. That is, the end portion of the heat pipe 7 located on one side surface of the track element 1 is bent toward another heat pipe 7 located on another side surface of the track element 1, and the bent distal end of the heat pipe 7 is located closer to another heat pipe 7.

[0023] As in Fig. 3, the heat pipes 7 are fixed to receiving grooves 13 formed in the bottom surface of the track member 1. The receiving grooves 13 are formed as cutout portions at both corner portions on the bottom surface side of the track member 1 and open in the bottom surface and side surfaces of the track member 1. In order to achieve favorable heat transfer between the receiving groove 13 and the heat pipe 7, a recessed groove 14 having a circular cross-sectional shape extending along an outer shape of the heat pipe 7 is further formed inside the receiving groove 13. Therefore, when the heat pipe 7 is inserted into the receiving grooves 13 and the track member 1 is fixed to the fixed portion, the heat pipe 7 is disposed between the fixed portion and the recessed groove 14 and is fixed to the inside of the receiving groove 13.

[0024] Furthermore, to achieve favorable heat transfer between the receiving groove 13 and the heat pipe 7, a heat-conductive substance (not shown), such as heat radiation grease, is disposed between the receiving groove 13 and the heat pipe 7, and the heat-conductive substance fills a tiny gap between the receiving groove 13 and the heat pipe 7. Thus, the heat transfer between the track element 1 and the heat pipe 7 can be performed smoothly.

[0025] With the track member 1 of the first embodiment, for example, even when only a portion of the track member 1 in the longitudinal direction is raised in temperature by frictional heat generated with the balls 3 due to the repeated movement of the moving block 2 along the track member 1, heat is quickly transferred from a high-temperature portion to a low-temperature portion through the heat pipe 7. Further, the plurality of heat pipes 7 are arranged in two rows with respect to the track member 1, and both ends of a heat pipe 7 belonging to one of the rows are arranged to overlap two different heat pipes 7 belonging to another of the rows in the width direction of the track member 1.Thus, the heat that has flowed from the high-temperature part of the track element into the heat pipe is transferred from the heat pipe to the low-temperature part of the track element, and is further transferred to a lower-temperature part of the track element along another heat pipe provided nearby. Therefore, a temperature increase is prevented only at a specific part of the track element, and the temperature can be instantly adjusted uniformly over the entire area of the track element in the longitudinal direction.

[0026] Furthermore, even if the heat pipes 7 are arranged in three or more rows with respect to the track member 1, as long as both ends of a heat pipe belonging to one of the rows are arranged to overlap two different heat pipes belonging to another of the rows in the width direction of the track member, heat transfer is uniformly performed by using the heat pipes 7, whereby the temperature can be uniformly adjusted over the entire area of the track member in the longitudinal direction.

[0027] In particular, in the first embodiment, which is shown in Fig. As shown in Figure 2, the end portions of the heat pipes 7 are bent toward the center of the track element 1 in the width direction, and the bent distal ends of the heat pipes 7 are arranged close to other heat pipes 7. Therefore, heat transfer can be performed evenly between the heat pipes 7 arranged adjacent to each other in the width direction of the track element 1. Thus, at this point as well, the temperature can be instantly adjusted uniformly over the entire area of the track element 1 in the longitudinal direction.

[0028] When a cooling device such as a heat sink is connected to one end of the heat pipe 7a protruding from one end of the track element 1, the heat pipe 7a removes heat from the end portion of the track element 1. Therefore, along with the effect of adjusting the temperature over the entire range of the track element 1 in the longitudinal direction, the entire track element 1 can be cooled. Similarly, when a heating device such as a heater is connected to the end portion of the heat pipe 7a, the entire track element 1 can be heated. Thus, if a device for detecting a temperature of the track element 1, such as a temperature sensor, is provided and the protruding end of the heat pipe 7a is cooled or heated based on a detection result, the entire track element 1 can be controlled to a freely selected temperature.

[0029] Fig. 4 is a diagram of a track element of a rolling guide device according to a second embodiment of the present invention.

[0030] In order to enable easy temperature management for an existing track element R in the second embodiment, heat pipes are not provided directly on the track element R. A fixing plate 8 for the track element R is provided between the track element R, and the fixed portion and the heat pipes 7 are provided in the fixing plate 8.

[0031] Fig.4 is a plan view of the fixing plate 8, and FIG. 5 is a sectional view of the fixing plate 8 taken along a plane orthogonal to the longitudinal direction. The fixing plate 8 is a plate-shaped member disposed between the track member R and the fixed portion and is formed to have a length substantially equal to that of the track member R. An upper surface of the fixing plate 8 has a fixing surface 80 for the track member R, and a stop surface 80a serving as a reference for fixing the track member is formed on one side of the fixing surface. Furthermore, the fixing plate 8 is fixed to the fixed portion by fixing bolts, and the fixing plate 8 has a plurality of bolt fixing holes 81 therefor formed at constant intervals in the longitudinal direction to pass through the fixing plate 8.Female screw holes 82 for fastening the track element R to the fastening plate 8 are each formed between adjacent screw fastening holes 81.

[0032] The heat pipes 7 are arranged in two rows with respect to the mounting surface 80 and are positioned on both sides of the plurality of bolt mounting holes 81 arranged in a row. One end of the heat pipe, positioned at an end portion of the mounting plate in the longitudinal direction, protrudes from the mounting plate. For example, a heat sink, which is a cooling device, or a heater, which is a heating device, is connected to the protruding end. The heat of the mounting plate 8 can be transferred to the outside through the heat pipe 7, or heat can be transferred to the mounting plate 8 from the outside.

[0033] Two receiving grooves 83 for fixing the heat pipes 7 are formed in the fixing surface 80, and the receiving grooves 83a and 83b extend from one end to the other end of the fixing plate 8. The plurality of heat pipes 7 are continuously arranged without any interval in each of the receiving grooves 83. That is, in each of the receiving grooves 83, one end of the heat pipe 7 is arranged near one end of another heat pipe 7 to a degree of being in contact with each other. Moreover, a seam of the heat pipes 7 in one receiving groove 83 is different in position with respect to a seam of the heat pipes 7 in another receiving groove 83 in the longitudinal direction of the track member R.That is, in the second embodiment, too, the plurality of heat pipes 7 are arranged in two rows along the longitudinal direction of the track member R, and both ends of a heat pipe 7 in one of the rows are arranged to overlap different heat pipes 7 in another of the rows in the width direction of the track member R, and this arrangement is repeated over the entire length of the track member R. In the second embodiment, the heat pipes 7 are arranged in two rows with respect to the fixing plate 8. However, the heat pipes 7 may be arranged in a staggered pattern in three or more rows, depending, for example, on the size of the fixing plate 8.

[0034] To achieve favorable heat transfer between the receiving groove 83 and the heat pipe 7, a circular cross-sectional shape of the receiving groove 83 is formed in an arc shape extending along the outer shape of the heat pipe 7. Therefore, when the heat pipes 7 are arranged with respect to the receiving grooves 83 and the track member R is fixed to the fixing plate 8, the heat pipes 7 are arranged between the track member and the receiving grooves 83, and the heat pipes 7 are fixed in the receiving grooves 83.

[0035] Furthermore, in the second embodiment, in order to achieve favorable heat transfer between the receiving groove 83 and the heat pipe 7, a heat-conductive substance (not shown) such as heat radiation grease is inserted between the receiving groove 83 and the heat pipe 7, and the heat-conductive substance fills a minute gap between the receiving groove 83 and the heat pipe 7.

[0036] When the track element R is to be installed on the fixed section using the fixing plate 8, the fixing plate 8 is first fixed to the fixed section using the fixing bolts. Then, the track element R, on the bottom surface of which the heat-conducting substance is applied, is fixed to the fixing plate 8 by the fixing bolts. This facilitates heat transfer between the track element and the fixing plate.

[0037] On the fixing plate 8, similar to the track member 1 of the first embodiment, the plurality of heat pipes 7 are arranged in two rows along the longitudinal direction of the track member R, and both ends of a heat pipe 7 in one of the two rows are arranged to overlap two different heat pipes 7 in another of the rows in the width direction of the track member R. Therefore, even if only a part of the track member R in the longitudinal direction is increased in temperature, heat is transferred from the track member R to the fixing plate 8 and is further instantly transferred in the longitudinal direction in the fixing plate 8 through the heat pipes 7. This prevents a temperature increase only at a specific part of the track member R, and the temperature can be instantly adjusted uniformly over an entire area of the track member R in the longitudinal direction.In addition, when a cooling device or a heating device is connected to one end of the heat pipe 7 projecting from one end of the fixing plate 8, the entire track element R can be controlled to a freely selected temperature.

[0038] Moreover, even if the heat pipes 7 are arranged in three or more rows with respect to the fixing plate 8, as long as both ends of a heat pipe belonging to any one of the rows are arranged to overlap two different heat pipes belonging to another one of the rows in the width direction of the fixing plate 8, the transfer of heat is performed uniformly by using the heat pipes 7, whereby it is possible to quickly adjust the temperature uniformly over the entire area of the fixing plate 8 in the longitudinal direction.

[0039] Thus, by using the fixing plate 8 according to the second embodiment, even if a track rail of the prior art which does not include the heat pipes 7 is provided, the temperature management therefor can be easily performed.

Claims

[1] Track element (1) of a rolling guide device, with a plurality of heat pipes (7), wherein the heat pipes (7) are arranged in at least two rows along a longitudinal direction of the track element (1), wherein in each row a plurality of heat pipes (7) are arranged at intervals along the longitudinal direction of the track element (1), each heat pipe (7) having two ends, and wherein a respective end of both ends of the same heat pipe (7) in a row is arranged so as to overlap a respective other heat pipe from the group of two heat pipes (7) arranged in another row in a width direction of the track element (1), and wherein one of the ends of a corresponding heat pipe (7) of the plurality of heat pipes (7) positioned at an end portion of the track element (1) in the longitudinal direction protrudes from the track element (1), and a cooling device or a heating device is connected to the projecting end of the heat pipe (7). [2] Track element according to claim 1, wherein receiving grooves (13) are formed for fixing the heat pipes (7) and a heat-conducting substance is arranged between the heat pipe (7) and the receiving groove (13). [3] A track member according to claim 1, wherein an end portion of each of the heat pipes (7) is bent toward a center of the track member (1) in the width direction. [4] A fixing plate (8) to be fixed when a track element (1) of a rolling guide device is to be installed on a fixed section, between the track element and the fixed section, the fixing plate (8) having a plurality of heat pipes (7), wherein the heat pipes (7) are arranged in at least two rows along a longitudinal direction of the track element (1), wherein in each row a plurality of heat pipes (7) are arranged at intervals along the longitudinal direction of the track element (1), each heat pipe (7) having two ends, and wherein a respective end of both ends of the same heat pipe (7) in a row is arranged so as to overlap a respective other heat pipe from the group of two heat pipes (7) arranged in another row in a width direction of the track element (1), and wherein one of the ends of a corresponding heat pipe (7) of the plurality of heat pipes (7) positioned at an end portion of the track member (1) in the longitudinal direction protrudes from the fixing plate (8), and a cooling device or a heating device is connected to the protruding end of the heat pipe (7). [5] The mounting plate according to claim 4, wherein receiving grooves (83) are formed for fixing the heat pipes (7) and a heat-conducting substance is arranged between the heat pipe (7) and the receiving groove (83). [6] The fixing plate according to claim 4, wherein an end portion of each of the heat pipes (7) is bent toward a center of the fixing plate (8) in the width direction.

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