Roller guide device

Abstract

Roll guide device, comprising: a rail element (1) with a rolling surface (11) extending along a longitudinal direction of the rail element (1); and a movable element (2) which is mounted on the rail element by arranging a large number of roller elements (6) between it, which roll on the rolling surface, so that the movable element (2) is movable along the rail element, and which has an endless circulation path (5) for the roller elements, the movable element includes: a main body element (21) with a load rolling surface (23) and a load-free return path (51) for the rolling elements, wherein the load rolling surface (23) is opposite the rolling surface of the rail element to define a load path (50) for the rolling elements, wherein the load-free return path (51) runs parallel to the load path; a pair of covers (22A and 22B) having direction change paths (52) to allow the rolling elements to move between the load path and the unloaded return path, and which is attached to both ends of the main body element in one direction of movement of the main body element; a measuring plate (3) which is arranged at least between the main body element (21) and a cover (22B) to form part of the continuous travel path, and which has a mounting section (32) for a sensor which is configured to detect an operating state of the movable element in relation to the rail element.

Description

Technical area

[0001] The present invention relates to a rolling guide device configured to guide a movable body such as a table so as to be reciprocated on a linear guide portion or a curved guide portion of industrial machines such as machine tools or various conveyors. State of the art

[0002] Previously, a rolling guide device of this type comprised a rail member and a movable member. The rail member has a rolling surface for rolling elements extending along a longitudinal direction of the rail member. The movable member is fixed to the rail member by interposing a large number of rolling elements that roll on the rolling surface, and is movable back and forth along the rail member. The movable member has a load rolling surface on which the rolling elements roll while carrying a load. The load rolling surface is disposed opposite the rolling surface of the rail member to define a load path for the rolling elements. Furthermore, the movable member has no-load paths for allowing the rolling elements to circulate the load path from one end to the other end. The load path and the no-load paths are continuously connected to define an endless circulating path for the rolling elements.With such a configuration, the movable element can be moved along the rail element without being limited in its stroke.

[0003] The product life of a rolling guide device essentially depends on the fatigue of the rolling surface of the rail element or the load rolling surface of the movable element. However, if the rolling surface and the load rolling surface, as well as the rolling elements such as balls or rollers that roll on them, are not sufficiently lubricated with lubricant, chipping of the rolling surface or the load rolling surface may occur prematurely, resulting in a shortened product life of the rolling guide device. If a lubricant defect occurs, the rolling resistance of the rolling elements increases. Consequently, there is a risk that, for example, the acceleration of the table movably supported by the rolling guide device will deteriorate, preventing the rolling guide device from performing its original function.

[0004] However, the rolling guide device is applicable to various uses, and a lubrication condition of the rolling surface or other parts is inevitably affected by, for example, a usage environment and an applied load depending on the usage (hereinafter referred to as "usage condition"). Therefore, in order to enable the rolling guide device to perform its original performance and fulfill its product life, it is desirable that an operating condition of the rolling guide device be continuously detected by various sensors and the supply of lubricant be controlled based on the detection results. Furthermore, it is desirable that an operation of an industrial machine in which the rolling guide device is installed be controllable as needed.

[0005] Patent Literature 1 discloses an example including a sensor mounted on the movable member and configured to detect the presence of lubricant on the rail member. However, the sensor is mounted on an outer side of the movable member. Although whether or not the lubricant adheres to the rail member can be checked, the lubrication state and the circulation state of the rolling elements in the endless circulation path of the movable member cannot be directly detected.

[0006] Further relevant prior art is disclosed in the following documents: US 6 333 628 B1, CH 674 668 A5 and EP 1 502 700 A1. Citation listPatent literature

[0007] [PTL 1] JP 2005-121215 A Disclosure of the present inventionThe problems to be solved by the invention

[0008] The present invention was conceived in view of the aforementioned problem, and it is an object of the present invention to provide a rolling guide device capable of incorporating therein various sensors configured to detect an operating state of a moving element with respect to a rail member, and directly detecting a circulation state of the rolling elements in an endless circulation path by using the various sensors. In particular, the subject matter of claim 1 is distinguished from the closest prior art of US Pat. No. 6,333,628 B1 by the measuring plate and the corresponding positioning as described in claim 1. Means to solve the problems

[0009] That is, according to one embodiment of the present invention, there is provided a rolling guide member comprising: a rail member having a rolling surface extending along a longitudinal direction of the rail member; and a movable member mounted on the rail member by interposing a large number of rolling elements that roll on the rolling surface so that the movable member is movable along the rail member, and having an endless circulation path for the rolling elements.The movable member further comprises: a main body member having a load rolling surface and a no-load return path for the rolling elements, the load rolling surface being opposed to the rolling surface of the rail member to define a load path for the rolling elements, the no-load return path being parallel to the load path; a pair of covers having direction-changing paths for allowing the rolling elements to move between the load path and the no-load return path, and mounted at both ends of the main body member in a moving direction of the main body member; a measuring plate disposed at least between the main body member and a cover to form part of the endless circulating path, and having a mounting portion for a sensor configured to detect an operating state of the movable member with respect to the rail member. Effects of the invention

[0010] According to the present invention, the measuring plate is provided between the main body member and the cover of the movable member, and the measuring plate has a mounting portion for various sensors configured to detect an operating state of the movable member with respect to the rail member. Thus, the rolling guide device incorporating various sensors can be easily provided. Furthermore, the measuring plate forms a part of the endless circulating path for the rolling elements. With the various sensors mounted on the measuring plate, the circulating state of the rolling elements in the endless circulating path can be directly detected. Therefore, an appropriate lubrication environment can be determined depending on a usage condition of the rolling guide device. Short description of the drawings Fig. 1 is a perspective view showing an example of a rolling guide device to which the present invention is applicable. Fig. 2 is a sectional view showing a configuration of an endless circulating path for balls. Fig. 3 is a sectional view showing a schematic configuration of a measuring plate according to a first embodiment of the present invention. Fig. 4 is a front view showing a measuring plate according to a second embodiment of the present invention. Embodiments of the present invention

[0011] Hereinafter, a rolling guide device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0012] Fig. 1 is a perspective view showing an example of a rolling guide device to which the present invention is applicable. The rolling guide device includes a rail member 1 and a movable member 2. The rail member 1 extends linearly. The movable member 2 is fixed to the rail member 1 by interposing a large number of balls, which are rolling elements. The rail member 1 is arranged on a fixed portion of various machine tools, and one type of movable body among various types is mounted on the movable member 2, whereby the movable body can be freely reciprocated along the rail member 1.

[0013] The rail member 1 is formed into an elongated body with a substantially rectangular cross-section. The rail member 1 has a plurality of screw fastening holes 12 arranged at predetermined intervals in a longitudinal direction, each penetrating from a top surface to a bottom surface. By using fastening screws inserted into the screw fastening holes 12, the rail member 1 can be firmly attached to a mounting portion. Two rolling surfaces 11 for the rolling elements are formed on the two right and left side surfaces of the rail member 1. The rail member has a total of four rolling surfaces 11. The number of rolling surfaces 11 formed on the rail member 1 is not limited to four.

[0014] Meanwhile, the movable member 2 essentially comprises a metal main body member 21, a pair of covers 22A and 22B made of synthetic resin, and a measuring plate 3. The pair of covers 22A and 22B are mounted at both ends of the main body member 21 in a moving direction of the main body member 21. The measuring plate 3 is arranged between one cover 22B and the main body member 21. The movable member 2 has a plurality of endless circulation paths for the balls that correspond to the rolling surfaces 11 of the rail member 1. Further, sealing members 4 configured to seal gaps between the movable member 2 and the rail member 1 are attached to the covers 22A and 22B to prevent dust or the like adhering to the rail member 1 from entering the endless circulation paths.

[0015] Fig. 2 shows a sectional view illustrating the endless circulation path. As in Fig. 2, the endless circulating path 5 includes a load path 50, a return path 51, and a pair of direction-changing paths 52. Furthermore, a part of the endless circulating path 5 is also formed in the measuring plate 3. The main body member 21 constituting the movable member 2 has a load rolling surface 23 opposite the rolling surface 11 of the rail member 1, and the rolling elements 6 roll while supporting a load between the rolling surface 11 of the rail member 1 and the load rolling surface 23 of the main body 21. In the endless circulating path 5, a path portion on which the rolling elements 6 roll while supporting the load corresponds to the load path 50. Further, the main body member 21 has the return path 51 extending parallel to the load path 50.Typically, the return path 51 is formed to pass through the main body member 21, and an inner diameter of the return path 51 is set to be slightly larger than a diameter of the rolling elements 6. With such a configuration, the rolling elements 6 roll on the return path without supporting the load.

[0016] The measuring plate 3 has a load-free connecting path 30 and a connecting return path 31. The load-free connecting path 30 is continuous with the load path 50 of the main body element 21. The connecting return path 31 is continuous with the return path 51 of the main body element 21. The rolling elements 6 roll in a load-free state without carrying the load in the load-free connecting path 30 and the connecting return path 31.

[0017] The direction change paths 52 are formed in the pair of covers 22A and 22B, respectively. One cover 22A is fixed to the end surface of the main body member 21. The direction change path 52 of the cover 22A connects one end portion of the load path 50 and one end portion of the return path 51 to each other, and allows the rolling elements 6 to move therebetween. The other cover 22B is fixed to the main body member by interposing the measuring plate 3 therebetween. The direction change path 52 of the cover 22B connects one end portion of the no-load connection path 30 and one end portion of the connection return path 31 of the measuring plate 3 to each other, and allows the rolling elements 6 to move therebetween.

[0018] Thus, when the measuring plate 3 and the pair of covers 22A and 22B are attached to the main body member 21, the endless circulating path 5 for the rolling elements 6, including the load-free connecting path 30 and the connecting return path 31 of the measuring plate 3, is completed. The rolling elements 6 roll on the endless circulating path 5, while the load is carried only in the load path 50 defined by the load rolling surface 23 of the main body member 21 and the rolling surface 11 of the rail member 1, which oppose each other.

[0019] Fig. 3 shows a representation of the measuring plate 3 according to a first embodiment of the present invention and a sectional view of the measuring plate along a plane perpendicular to the longitudinal direction of the rail element 1. The measuring plate 3 has spaces in its interior that serve as mounting sections 32 for various sensors, wherein a plurality of sensor types can be attached to the mounting sections 32. Furthermore, as shown in Fig. 1, signal cables 33 of the plurality of sensors accommodated in the mounting sections 32 are bundled into a single cable, led out of the measuring plate 3 and connected to a controller (not shown). Fig. 3 shows a schematic representation of the arrangement of the mounting portions 32 for the various sensors, wherein the specific positions and shapes of the mounting portions 32 in the measuring plate 3 can be changed appropriately depending on the objects to be used and measured by the sensors.

[0020] Examples of the sensors accommodated in the mounting portions 32 include a contamination sensor configured to detect contamination of the lubricant, a measuring head for a linear encoder configured to measure the amount of movement of the movable member with respect to the rail member, and an acceleration sensor.More specifically, for the contamination sensor, a photoelectric conversion type particle counter using laser light, an infrared wavelength absorption type moisture-in-oil sensor, a lubricating oil deterioration degree measuring sensor using a dielectric constant, a lubricating oil iron powder concentration measuring sensor, and a lubricating oil deterioration degree measuring sensor using a color tone difference may be further used, and various sensors for detecting a contamination state of the lubricating oil may be suitably accommodated in the mounting portions 32 of the measuring plate 3.

[0021] Furthermore, the measuring plate 3 forms a part of the endless circulation path 5, and thus, with the measuring plate 3, the supply of a lubricant can be carried out with respect to the rolling elements 6 rolling on the endless circulation path 5. In particular, a supply opening 34 (see Fig. 1) for lubricant is formed in the measuring plate 3, thereby forming a lubricant path extending from the supply port 34 to the no-load communication path 30 or the communication return path 31. A pipe, such as a flexible pipe, is connected to the supply port 34, and the lubricant is supplied to the supply port 34 by a lubricant pump provided outside the device.

[0022] In this case, a sensor configured to detect lubricant flow in the lubricant path may be provided on the measuring plate 3. With such a sensor, the supply state of the lubricant with respect to the endless circulation path 5 can be monitored substantially accurately. As a result, insufficient lubrication of the rolling surface 11 of the rail member 1 or the load rolling surface 23 of the movable member 2 can be prevented.

[0023] The rolling guide device according to the present embodiment, which will be described with reference to the drawings, includes a type in which the rail member is disposed on the fixed portion. However, the present invention is also applicable to a rolling guide device, such as a ball spline device or a ball screw device, of a type in which the rail member is formed into a rod shaft shape such that only both ends thereof are supported by the fixing portion. Furthermore, the present invention is also applicable to a rolling guide device incorporated in various actuators.

[0024] Fig. 4 is a view showing the measuring plate according to a second embodiment of the present invention, and is a front view showing the measuring plate 3 as viewed from the side of a joining surface with respect to the main body member 21.

[0025] The measuring plate 3 has a mounting portion 32 that is open toward the main body member 21. A vibration sensor 35 and a plurality of proximity sensors 36 are housed in the mounting portion 32. The vibration sensor 35 and the proximity sensors 36 are mounted on an electronic board 37 and are housed together with the electronic board 37 in the mounting portion 32. Further, a connector 38 for outputting a signal to the outside of the measuring plate 3 and supplying power to the electronic board 37 is connected to the electronic board 37, and the connector 38 is provided so as to pass through the measuring plate 3.

[0026] An acceleration sensor can be used as the vibration sensor 35. The vibration sensor 35 is held in a state in which the vibration sensor 35 is accommodated in the mounting portion 32 of the measuring plate 3, in abutment with the main body member 21 of the movable member 2. Specifically, the vibration sensor 35 is directly connected to the end surface of the main body member 21 to which the measuring plate 3 is attached. Furthermore, the proximity sensors 36 are attached to an inner wall of the mounting portion 32 at positions adjacent to the no-load connection paths 30 of the measuring plate 3. In the Fig. In the example shown in Fig. 4, the proximity sensors 36 are provided with respect to the two load-free connecting paths 30 arranged near the fastening section 32.

[0027] A microcontroller serving as a controller with a RAM and a ROM is mounted on the electronic board 37. Detection signals from the vibration sensor 35 and the proximity sensors 36 are input to the controller through, for example, an A / D converter. The controller executes a program stored in advance in the ROM, processes the detection signals from the vibration sensor and the proximity sensors, and outputs the various signals to the outside via the connector 38. An output destination of the signals generated by the controller may include, for example, a warning device or a user interface such as a display. It is not always necessary to mount the controller on the electronic board 37 housed in the mounting portion 32.Also, only the sensors 35 and 36 may be accommodated in the mounting portion 32, and the controller provided on the outside of the measuring plate 3 and each of the sensors 35 and 36 may be connected to each other via the connector 38.

[0028] The rolling guide device of this type is used, for example, as a part for moving a worktable and a headstock in a numerically controlled machine tool such as a machining center. An operating condition of the rolling guide device can significantly affect the machining accuracy of a workpiece by the numerically controlled machine tool. Thus, with a structure in which the detection signals from the various sensors provided in the measuring plate 3 are directly input to a controller of the numerically controlled machine tool, the operation of the numerically controlled machine tool can be controlled based on the detection signals, effectively reducing the occurrence of defective products.

[0029] As described above, according to one embodiment of the present invention, the measuring plate 3 is arranged between the main body member 21 constituting the movable member 2 and the cover 22B, and the mounting portions 32 of various sensors are provided in the measuring plate 3. Thus, the various sensors for detecting an operating state of the rolling guide device can be easily incorporated into the movable member 2. Furthermore, by using the detection results of the sensors, the operating state of the rolling guide device can be monitored in real time, thereby maintaining the optimal operating state of various industrial machines using the rolling guide device.

[0030] Furthermore, the measuring plate 3 forms part of the endless circulating path 5 for the rolling elements 6. Thus, the circulating state of the rolling elements 6 in the endless circulating path 5 can be directly detected using the sensors provided in the measuring plate 3, making it possible to adjust appropriate lubricant supply timing, lubricant supply duration, lubricant supply amount, and appropriate lubricant supply positions on the rail element 1 depending on the usage conditions of the rolling guide device. With this structure, the operating state of the rolling guide device can always be maintained at a high level.

[0031] In the rolling guide device according to the embodiments described with reference to the drawings, balls are used as rolling elements. However, the present invention is also applicable to a rolling guide device using rollers.

Claims

[1] Rolling guide device, comprising: a rail element (1) having a rolling surface (11) extending along a longitudinal direction of the rail element (1); and a movable element (2) mounted on the rail element by interposing a large number of rolling elements (6) rolling on the rolling surface so that the movable element (2) is movable along the rail element, and having an endless circulation path (5) for the rolling elements, wherein the movable element comprises: a main body element (21) having a load rolling surface (23) and a load-free return path (51) for the rolling elements, the load rolling surface (23) being opposite the rolling surface of the rail element to define a load path (50) for the rolling elements, the load-free return path (51) being parallel to the load path; a pair of covers (22A and 22B) having direction change paths (52) for allowing the rolling elements to move between the load path and the no-load return path, and mounted at both ends of the main body member in a direction of movement of the main body member; a measuring plate (3) arranged at least between the main body member (21) and a cover (22B) to form part of the endless circulating path, and having a mounting portion (32) for a sensor configured to detect an operating state of the movable member with respect to the rail member. [2] Rolling guide device according to claim 1, wherein the measuring plate (3) comprises: a load-free connecting path (30) opposite the rolling surface (11) of the rail element (1) and configured to guide the rolling elements (6) between the load path (50) and the direction change path (52); and a connecting return path (31) configured to guide the rolling elements between the return path (51) of the main body member and the direction change path (52) of the cover. [3] A rolling guide device according to claim 1, wherein the measuring plate (3) has a supply port (34) to which a supply pipe for lubricant is connected, and a lubricant path extending from the supply port and configured to supply lubricant to the rolling surface (11) of the rail member (1) or the rolling elements (6).

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