WO2019013220A1

WO2019013220A1 - Rolling device

Info

Publication number: WO2019013220A1
Application number: PCT/JP2018/026085
Authority: WO
Inventors: 義夫滝; 智則金子; 清水　博之; 友子天野; 嘉伸矢野; 佐藤　慎一郎
Original assignee: Thk株式会社; 清水電設工業株式会社
Priority date: 2017-07-12
Filing date: 2018-07-10
Publication date: 2019-01-17
Also published as: JP7016365B2; JPWO2019013220A1; TW201908615A

Abstract

This rolling device is provided with an inner member having an orbital surface on the outer surface, an outer member arranged outside of the inner member and having an orbital surface opposite of the orbital surface of the inner member, and a rolling body rollably arranged between the two orbital surfaces. In the rolling device, at least one of the orbital surface of the inner member, the orbital surface of the outer member, and the rolling body is configured from a base material (11) formed from a metal material, an underlayer (12) formed on the surface of the base material (11), and a functional layer (13) formed on the surface of the underlayer (12), and the functional layer (13) is configured as a composite layer having a laminate structure formed by alternately laminating WC layers and C layers. By forming a coating layer on constituent members, it is possible to achieve a rolling device which prevents metal contact and improves wear characteristics and lubrication life characteristics.

Description

Rolling device

The present invention relates to a rolling device.

As mechanical elements conventionally used, for example, rolling devices such as ball screws, linear guides, linear motion bearings, ball splines and the like are known. The rolling device includes an inner member having a raceway surface on the outer surface, an outer member having a raceway surface facing the raceway surface of the inner member and disposed outside the inner member, and the two raceways. This is a device in which the outer member can freely reciprocate or rotate in the axial direction or the circumferential direction of the inner member by having a plurality of rolling elements disposed rollably between the surfaces.

In this type of rolling device, since a plurality of rolling elements disposed between the inward member and the outward member repeatedly perform rolling motion, contact stress is repeatedly applied to the component members of these rolling devices. Will be added. Therefore, metal materials, resin materials and the like excellent in fatigue life, wear resistance and the like are generally adopted as materials constituting the inward member, the outward member and the rolling element.

In addition, since rolling devices of this type are sometimes used in applications requiring a clean environment such as clean rooms, semiconductor manufacturing devices, liquid crystal panel manufacturing devices, food processing devices, etc. or under a vacuum environment, With respect to the materials constituting the member, the outer member, and the rolling element, a film made of a solid lubricant is sometimes formed and used. For example, in Patent Document 1 below, in the rolling device in which one moving member and the other moving member relatively move linearly through the rolling elements in contact with the respective guide surfaces, the two moving members or the rolling elements For at least one of the above, there is disclosed a technique for forming a fluorocarbon resin film on the surface through an electroless nickel film. And according to the description of the following patent document 1, a semiconductor manufacturing apparatus, a liquid crystal panel manufacturing apparatus, and a food processing apparatus are formed by forming a fluorocarbon resin film on an element forming a rolling device through an electroless nickel film. It can be suitably used in an environment requiring a clean atmosphere, etc., and can also be used in a vacuum, high temperature, corrosive atmosphere environment.

However, the technology described in the following Patent Document 1 is to form a fluorocarbon resin film after forming an electroless nickel film on a substrate such as a metal material, a technology having many manufacturing processes and cost increase It is. As described in Patent Document 1, the electroless nickel film and the electroless nickel-phosphorus film originally have an anticorrosive effect on the film itself, and an effect of improving the corrosion resistance can be obtained. If a rolling device having both rolling fatigue resistance and corrosion resistance can be realized by applying only a coating or an electroless nickel-phosphorus coating, the industrial utility value becomes extremely high. However, as conventionally known, fine cracks and pores are present in the electroless nickel film, and therefore, when the film in such a state is used as a component of the rolling device, repeated contact is made. The peeling of the film or the like is generated by the stress, or the rust is generated from the crack or the hole as a starting point, so that the performance as a rolling device could not be sufficiently exhibited. As understood from this fact, the technology for forming a coating film which can suitably improve the wear characteristics and the lubricating life characteristics of the rolling device has not been completed in the past.

On the other hand, tools used in metal or plastic cutting and forming processes are often coated to improve their useful life and processing conditions, and such coatings have known methods such as CVD and PVD. It is used.

Japanese Patent Application Laid-Open No. 10-325414

However, in a rolling device in which a contact stress is repeatedly applied to a component, applying a coating of a mixture of tungsten carbide (WC) and carbon (C) to the component has not been conventionally performed. The optimum conditions for the coating were not yet known. In particular, in the rolling device, while having high hardness corresponding to the contact stress repeatedly applied, it is excellent in adhesion to the base material and has high ability to follow elastic deformation, and further, defects such as surface layer cracking hardly occur. There is a need to realize a coating, and no coating technology has been realized that satisfies such various required qualities.

The present invention has been made in view of the various problems existing in the above-mentioned prior art, and the object thereof is to prevent metal contact by forming a coating layer on a component, and to wear characteristics and lubrication life. An object of the present invention is to realize a rolling device with improved characteristics.

The rolling device according to the present invention comprises an inward member having a raceway surface on the outer surface, and an outward member having a raceway surface opposed to the raceway surface of the inward member and disposed outside the inward member. A rolling device disposed between the two raceway surfaces so as to roll freely, wherein the raceway surface of the inner member, the raceway surface of the outer member, and the rolling member At least one of them is composed of a base material made of a metal-based material, an underlayer formed on the surface side of the matrix, and a functional layer formed on the surface side of the underlayer, The functional layer is characterized in that it is configured as a composite layer having a laminated structure in which WC layers and C layers are alternately laminated.

According to the present invention, by forming a coating layer on a component, metal contact can be prevented, and a new rolling device having improved wear characteristics and lubrication life characteristics can be realized.

FIG. 1 is a view for explaining the specific contents of a coating layer according to the present invention, and a portion (a) in the figure is a schematic view showing a cross-sectional configuration of the coating layer, and a portion (b) These are photographs showing a part of the cross-sectional configuration of the coating layer. FIG. 2 is a graph showing the results of the oil lubrication load endurance test, and the test results of the respective test products shown on the vertical axis are represented as the travel distance shown on the horizontal axis. FIG. 3 is a graph showing the results of the non-lubricant load endurance test, and the test results of the respective test products shown on the vertical axis are represented as the travel distance ratio shown on the horizontal axis. FIG. 4 is a view for explaining a modified embodiment of the base layer according to the present invention, and a section (a) in the figure is a schematic view showing a cross-sectional configuration of the coating layer, and a section (b) is It is a graph which shows the change of the C component rate in the film thickness direction of the base layer which comprises a coating layer. FIG. 5 is a view illustrating one of the optimum design conditions of the coating hardness of the coating layer according to the present invention, and a diagram (a) in the figure is a schematic view showing a cross-sectional configuration of the coating layer Section (b) is a graph showing a design example of the hardness value in the film thickness direction of the coating layer. FIG. 6 is an external perspective view illustrating an embodiment in which the rolling device according to the present embodiment is configured as a linear guide device. FIG. 7 is a cross-sectional view for explaining an infinite circulation path provided in the linear guide device shown in FIG. FIG. 8 is a view exemplifying a case where the rolling device according to the present embodiment is configured as a ball screw device. FIG. 9 is a view illustrating the case where the rolling device according to the present embodiment is configured as a spline device. FIG. 10 is a partial vertical perspective view illustrating an embodiment in which the rolling device according to the present embodiment is configured as a rotating bearing device. FIG. 11 is a longitudinal sectional view of the rotary bearing device shown in FIG. FIG. 12 is an external perspective view illustrating an embodiment in which the rolling device according to the present embodiment is configured as a sliding screw device. FIG. 13 is a view for explaining various application examples of the present invention, and is an external perspective partial cross-sectional view showing a rolling device of a type in which a linear motion guide and a ball screw are combined to form an integral structure. .

Hereinafter, preferred embodiments for carrying out the present invention will be described using the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

First, the specific content of the coating layer which concerns on this invention applicable to the structural member of a rolling device is demonstrated using FIG. Here, FIG. 1 is a figure for demonstrating the specific content of the coating layer based on this invention, and the figure (a) in the figure in the figure is the schematic diagram which showed the cross-sectional structure of a coating layer, (B) is a photograph which showed a part of cross-sectional structure of a coating layer. The coating layer according to the present invention includes an inner member having a raceway surface on the outer surface, and an outer member provided with a raceway surface facing the raceway surface of the inner member and disposed outside the inner member. The present invention is applied to a rolling device including a rolling element disposed rollably between both raceway surfaces, and includes a raceway surface of an inward member, a raceway surface of an outward member, and a rolling At least one of the moving bodies is constituted by a base material made of a metal-based material, an underlayer formed on the surface side of the matrix, and a functional layer formed on the surface side of the underlayer, Specific embodiment examples will be described later.

As shown in the partial view (a) of FIG. 1, the coating layer according to the present invention includes a base material 11 made of a metal-based material, an underlayer 12 formed on the surface side of the matrix 11, and an underlayer 12. And the functional layer 13 formed on the surface side of

The base material 11 is assumed to be a metal material generally used for a rolling device, and is made of, for example, bearing steel such as SUJ 2 or the like, high carbon steel, tool steel, or the like. However, the applicable range of the base material according to the present invention is not limited to such iron-based metals, and includes non-ferrous metal alloys such as titanium alloys and aluminum alloys.

The foundation layer 12 is made of, for example, W (tungsten), and is a layer that suitably connects the base material 11 and the functional layer 13 described later.

The functional layer 13 is configured as a composite layer having a laminated structure in which a WC layer made of tungsten carbide and a C layer made of carbon are alternately laminated. The C layer according to the present invention is assumed to be configured as a coating layer made of DLC (Diamond-like Carbon), and constitutes a coating layer having a very high hardness single layer structure. . On the other hand, the WC layer laminated alternately with the C layer made of DLC constitutes a coated layer having a hardness lower than that of the C layer made of DLC. Therefore, by alternately laminating the C layer having high hardness and the WC layer having high hardness, the functional layer 13 as a whole has high adaptability to elastic deformation and a very suitable coating layer which hardly causes a crack in the film. It has become.

In the coating layer according to the present invention, the outermost surface of the composite layer constituting the functional layer 13 is constituted by the C layer. The components of the rolling device on which the coating layer is formed are required to have a high surface hardness in order to be subjected to repeated stress. Therefore, in the present invention, by forming the C layer on the outermost surface of the composite layer constituting the functional layer 13 having a laminated structure, the coating layer having a single-layer structure having a very high hardness is a constituent member It is possible to form on the outermost surface of With such a configuration, durability to a stress load required of the rolling device is exhibited, and it is possible to improve wear characteristics and lubrication life characteristics.

Furthermore, in the coating layer according to the present invention, as described above, the underlayer 12 is made of W (tungsten), but the WC layer is the connecting surface of the underlayer 12 and the functional layer 13 in the functional layer 13. It is configured to be The connection surface with the base layer 12 in the functional layer 13 formed on the surface side of the base layer 12 is a WC layer which forms a soft coating layer having a hardness lower than that of the C layer, and also forms the base layer 12 By forming a WC layer that is a metal material of the same system as W (tungsten), the base material 11, the base layer 12, and the functional layer 13 are bonded with high adhesion. That is, it can be said that the coating layer which concerns on this invention is a coating layer which is very hard to peel off. Therefore, according to the coating layer according to the present invention, it is possible to realize a new rolling device having improved wear characteristics and lubrication life characteristics.

In the configuration of the present invention described above, the W (tungsten) composition ratio of the WC layer constituting the functional layer 13 is as follows:
0% by weight <w ≦ 30% by weight
It is preferable to be configured under the condition satisfying the inequality below. The conditional expression consisting of 0% by weight <w ≦ 30% by weight is found by an experiment conducted by the inventors. By satisfying the conditional expression, the W (tungsten) composition in the functional layer 13 is satisfied. Since the optimization of the ratio is realized, it is an effective condition for forming a film surface which is hard to wear on the raceway surface of the rolling device.

Furthermore, the hardness value of the composite layer as the functional layer 13 constituting the coating layer according to the present invention is configured to have a Vickers hardness Hv of 800 to 1,500. In experiments conducted by the inventors in finding such a condition value, the hardness measurement of the composite layer is performed with a nano indenter, and the functional layer 13 constituting the coating layer according to the present invention has a Vickers hardness Hv. It is configured to have a value of 12 GPa to 17 GPa corresponding to 800 to 1,500. When the Vickers hardness Hv is less than 800 (12 GPa), there is a problem with the wear resistance, and the Vickers hardness is such that the condition of such hardness value is set for the composite layer constituting the functional layer 13 If Hv is greater than 1500 (17 GPa), coating cracking will occur. With regard to the hardness value of the composite layer constituting the functional layer 13, the Vickers hardness Hv is preferably 800 to 1,500 to be suitably used for a rolling device that generates high surface pressure and shear force. Can be realized.

In the above, the description about the suitable formation conditions of the coating layer which concerns on this invention which the inventors discovered was performed. Next, since the inventors have conducted verification experiments on the effects obtained by satisfying the formation conditions of the coating layer according to the present invention described above, the results will be described.

First, the inventors conducted a verification experiment on the load durability performance of the rolling device under the condition where oil lubrication was performed. This oil lubrication load endurance test was conducted by setting a linear guide to this tester using a load endurance tester installed in a laboratory room temperature environment. The linear guide prepares the coating member according to the present invention formed on the component members under various condition values, and the existing product without the coating layer according to the present invention which is the prior art, and forms a linear guide. It was decided to compare the endurance performance of the two by repeatedly reciprocating the moving block relative to the rail.

As more specific conditions of the oil lubrication load endurance test, the test product is an existing product as comparative example 1 and the comparative example 2 has a hardness value of 10 GPa of the functional layer 13 and further the embodiment of the present invention The hardness value of the functional layer 13 prepared five types of Examples 1, 2, 3 and 12 of 17 GPa as a form. Lubricating grease was initially sealed for the five types of test products, and then lubrication was continued under the condition of 0.5 cm ³ / min. A constant load of 12.6 kN in radial load is always applied to the moving block that constitutes the linear guide, and the maximum moving speed of 60 m / min and acceleration / deceleration of 9.8 m / s ² as relative moving conditions of the moving block with respect to the track rail. Each condition value of (1.0 G) and stroke 350 mm was set. Under these conditions, the moving block was repeatedly reciprocated with respect to the track rail constituting the linear guide, and the distance traveled by the linear guide while maintaining the performance was recorded, and the evaluation was made based on the distance traveled.

The results obtained under the test conditions described above are shown in FIG. Here, FIG. 2 is a graph showing the result of the oil lubrication load endurance test, and the test result of each test product shown on the vertical axis is represented as the travel distance shown on the horizontal axis.

As is clear from FIG. 2, in the oil lubrication load endurance test conducted this time, results superior to the existing products were obtained in all the examples. However, for Examples 1, 2 and 3 with hardness values of 12, 15 and 17 GPa of the functional layer 13 according to the embodiment of the present invention, the travel distance is 2500 to 4500 km, which is about 3 times longer than the existing products. Indicates the distance. From this result, the condition that the hardness value of the composite layer constituting the functional layer 13 performed by the nano indenter is 12 GPa to 17 GPa as the condition value of the functional layer 13 of the present invention is compared to the prior art. It can be evaluated that the longevity can be realized. That is, according to the oil lubrication load endurance test conducted by the present inventors, it has been confirmed that the coating layer according to the present invention suitably shows the improvement effect of the lubrication state in the oil lubrication environment.

In addition, as for the hardness value of the functional layer 13 of 10 GPa as an embodiment of the present invention, no significant difference was seen from the existing products. However, from these results, it was possible to confirm the effectiveness of setting the lower limit value of the condition value of the functional layer 13 of the present invention to 12 GPa.

Next, the inventors conducted a verification experiment on the load durability performance of the rolling device in a non-lubricated environment in which oil lubrication is not performed. This non-lubricated load endurance test was conducted by setting a linear guide to this tester using a load endurance tester installed under a room temperature environment in a laboratory. For the linear guide, prepare an embodiment in which the hardness value of the coating layer according to the present invention is 15 GPa and a MoS ₂ film formed as a comparative example for the component members, On the other hand, it was decided to compare the durability performance of the two by repeatedly reciprocating the moving block. The hardness value of the coating layer according to the present invention is 15 GPa because the hardness value of the composite layer constituting the functional layer 13 performed by the nano indenter is the condition value of the functional layer 13 of the present invention. A median value of about 12 GPa to 17 GPa is representatively selected.

Further, as more specific conditions of the no-lubrication load endurance test, one set of each of the two types of the above-described test products was prepared, and data of each was collected. The lubrication conditions were unlubricated, and the supply of lubricant during the test was also stopped. A constant load of 3.17 kN in radial load is constantly applied to the moving block that constitutes the linear guide, and the maximum moving speed of 30 m / min and acceleration / deceleration of 9.8 m / s ² as relative moving conditions of the moving block with respect to the track rail. Each condition value of (1.0 G) and stroke 350 mm was set. Under these conditions, the moving block was repeatedly reciprocated with respect to the track rail constituting the linear guide, and the distance traveled by the linear guide while maintaining the performance was recorded, and the evaluation was made based on the distance traveled.

The results obtained under the test conditions described above are shown in FIG. Here, FIG. 3 is a graph showing the results of the non-lubricant load endurance test, and the test results of the respective test products shown on the vertical axis are represented as the travel distance ratio shown on the horizontal axis.

As apparent from FIG. 3, in the non-lubricated load endurance test carried out this time, assuming that the travel distance ratio is 1 when the MoS ₂ film is formed as a comparative example conventionally used in a non-lubricated environment, For the embodiment in which the hardness value of the coating layer according to the present invention was 15 GPa, the travel distance ratio was 3.2. That is, the coating layer according to the present invention exhibited a life extending effect of about three times or more as compared with the prior art. In addition, about the fact that the result obtained in the non-lubricant load endurance test realized the life extension of about 3 times or more compared to the prior art, the improvement effect magnification is almost the same as the effect in the oil lubrication load endurance test . From this result, the condition that the hardness value of the composite layer constituting the functional layer 13 performed by the nano indenter is 12 GPa to 17 GPa as the condition value of the functional layer 13 of the present invention is compared to the prior art. It can be evaluated that the longevity can be realized. That is, according to the lubricant-free load endurance test conducted by the inventors, it has been confirmed that the coating layer according to the present invention suitably exhibits a long life effect even in a lubricant-free environment.

In the above, the description about the suitable formation conditions of the coating layer which concerns on this invention which the inventors discovered was performed. As described above, the coating layer according to the present invention can be suitably used for a rolling device which is subject to repeated rolling load and sliding load, and is about three times or more the conventional art. Achieved a long life. However, the preferable conditions for forming the coating layer according to the present invention described above relate to the functional layer 13. Therefore, the inventors worked on the modification of the underlayer 12 while considering the further improvement of the present invention. Then, as a result of intensive studies by the inventors, the main component is made of W (tungsten) instead of the underlayer 12 made of W (tungsten) alone, and the functional layer 13 from the connection surface with the base material 11 It has been confirmed that the base layer 12 excellent in peeling resistance can be formed by adopting the base layer 12 configured so that the C component is gradually increased toward the connection surface with. FIG. 4 is shown as a schematic view showing such a new base layer 12. Here, FIG. 4 is a view for explaining a modified embodiment of the base layer according to the present invention, and a portion (a) in the figure is a schematic view showing a cross-sectional configuration of the coating layer, a portion ((a) b) is a graph which shows the change of the C component rate in the film thickness direction of the base layer which comprises a coating layer.

As shown in FIG. 4, the base layer 12 according to the modified embodiment is mainly composed of W (tungsten), but in the range of a constant film thickness from the connection surface with the base material 11, the C component ratio Is 0 (zero)%, and is composed only of W (tungsten). The underlayer 12 according to the modified embodiment is configured such that the C component ratio gradually increases toward the surface layer side that is the connection surface with the functional layer 13, and the underlayer 12 connected to the functional layer 13. The outermost surface portion of is configured such that the C component ratio is 80%. As described above, with respect to the base layer 12 constituting the coating layer according to the present invention, the film is formed so that the C component ratio in W (tungsten) changes stepwise in the film thickness direction, whereby the peeling resistance is excellent. The effect of being the underlayer 12 can be obtained.

In addition, the inventors considered that when performing a film improvement experiment, a film that does not peel off in a high surface pressure environment is required as the optimum performance for the rolling device, so adhesion with the base material 11 is important. . In addition, in order to prevent abrasion of the mating material (rolling surface), it is necessary to reduce the unevenness on the surface of the ball, and it has been confirmed that it is effective to increase the hardness. In order to balance these two conditions, a method was adopted in which a portion close to the base material 11 was softened, laminated while inclining the hardness, and making the surface as hard as possible. Based on this idea, as a result of the inventors' earnest research, they have come to find conditions further excellent in film adhesion. The results are shown in FIG. Here, FIG. 5 is a diagram illustrating one of the optimum design conditions of the film hardness of the coating layer according to the present invention, and a diagram (a) in the diagram is a schematic diagram showing the cross-sectional configuration of the coating layer Part (b) of the drawing is a graph showing a design example of the hardness value in the film thickness direction of the coating layer.

In the improved example shown in FIG. 5, the coating hardness is increased from the connection surface of the base layer 12 with the base material 11 toward the surface of the functional layer 13 and the composite layer constituting the functional layer 13 An example configuration is shown where the coating hardness of the outermost surface C layer (DLC) is gradually reduced towards the surface. The inventors found that the wear of the sliding surface is increased when the outermost layer of the coating layer is a hard C layer (DLC) as a result of the experiment, but the final step of the functional layer 12 (that is, slightly before the outermost layer) is the most By making the hard outermost layer C layer (DLC) slightly soft, the outermost layer C layer (DLC) functions as a conformal layer, and the adhesion of the film is improved. By realizing the coating film satisfying the design condition of the coating film hardness shown in FIG. 5 as described above, a coating layer having further excellent adhesion of the film is realized, and a rolling device realizing a long life can be obtained. It became clear.

In the above, the description about the suitable formation conditions of the coating layer which concerns on this invention which the inventors discovered was performed. As described above, the coating layer according to the present invention can be suitably used for a rolling device that receives repeated rolling load and sliding load. Then, the case in which the coating layer according to the present invention is applied to a rolling device will be described next.

[Example of application to rolling device]
A specific embodiment of a rolling device using a coating layer according to the present invention will be described using the drawings. In addition, the embodiment of the rolling device illustrated below does not limit the invention according to each claim, and all combinations of the features described in the embodiments are essential for the solution means of the invention. Not necessarily. Further, the “rolling device” in the present specification includes, for example, general rolling bearings used in machine tools and the like, non-lubricated bearings used in vacuum, linear guides and linear guides, ball spline devices, ball screw devices, It includes devices with all rolling and sliding operations, such as roller screw devices, cross roller rings, etc.

(Example of application to linear guide device)
The rolling device according to the present embodiment can be configured as a linear guide device as shown in FIG. 6 and FIG. 7, and by forming the coating layer described above on such a linear guide device, wear characteristics are obtained. And a new rolling device with improved lubrication life characteristics can be realized. Here, FIG. 6 is an appearance perspective view illustrating one form of the linear guide device according to the present embodiment. 7 is a cross-sectional view for explaining an infinite circulation path provided in the linear guide device shown in FIG.

First, the configuration of the linear guide device 40 illustrated in FIGS. 6 and 7 will be described. The linear guide device 40 as the rolling device according to the present embodiment includes the track rail 41 as the inward member and the track rail 41. And a moving block 43 as an outer member slidably mounted via balls 42 installed as a large number of rolling elements. The track rail 41 is a long member whose cross section orthogonal to the longitudinal direction is formed in a substantially rectangular shape, and on the surface (upper surface and both side surfaces), a track surface which becomes a track when the ball 42 rolls. The rolling element rolling surface 41 a is formed over the entire length of the track rail 41.

Here, the track rail 41 may be formed to extend linearly or may be formed to extend curvilinearly. Further, although the number of rolling element rolling surfaces 41a illustrated in FIGS. 6 and 7 is a total of four in two on the left and two on the left and right, the number of the rows is arbitrarily changed according to the application of the linear guide device 40 can do.

On the other hand, the moving block 43 is provided with a load rolling element rolling surface 43a as a raceway surface at a position corresponding to the rolling element rolling surface 41a. A load rolling path 52 is formed by the rolling element rolling surface 41 a of the raceway rail 41 and the load rolling element rolling surface 43 a of the moving block 43, and a plurality of balls 42 are sandwiched. Furthermore, the moving block 43 is provided with four non-load rolling paths 53 extending in parallel to the rolling element rolling surfaces 41 a, and a direction changing path 55 connecting each non-loading rolling path 53 and each load rolling path 52. It is done. A combination of one load rolling path 52 and no load rolling path 53 and a pair of direction changing paths 55 connecting them forms one infinite circulation path (see FIG. 7).

A plurality of balls 42 are installed in the infinite circulation path constituted by the load rolling path 52, the no-load rolling path 53, and the pair of

direction changing paths

55, 55 in an infinitely circulating manner, whereby the moving block 43 is formed. Reciprocation relative to the track rail 41 is possible.

In the linear guide device 40 according to the present embodiment having the above configuration, the rolling element rolling surface 41 a of the track rail 41 as the inward member and the load rolling element rolling surface of the moving block 43 as the outward member. A coating layer composed of the above-described base layer 12 and the functional layer 13 can be formed on at least one of the balls 42 installed as a plurality of rolling elements and 43a.

For example, by forming a coating layer including the foundation layer 12 and the functional layer 13 on the surface of the ball 42 installed as a plurality of rolling elements, the rolling element rolling surface 41 a of the track rail 41 and the moving block 43 The metal contact between the load rolling element rolling surface 43 a and the ball 42 is prevented. The outermost surface of the functional layer 13 is a C layer which is a carbon-based coating film, and the functional layer 13 itself is a composite layer having a laminated structure, and the coating layer itself has lubricity. Can exhibit the reduction of frictional resistance and the function as a solid lubricant. Furthermore, by forming a coating layer consisting of the base layer 12 and the functional layer 13 on the surface of the ball 42, metal contact can be prevented even in an environment where an oil film is not formed. It is possible to extend the product life.

(Example of application to rolling element screw device)
Moreover, the rolling device according to the present embodiment can be configured as, for example, a ball screw device 56 as shown in FIG. FIG. 8 is a view exemplifying a case where the rolling device according to the present embodiment is configured as a ball screw device. The ball screw device 56 is a device including a screw shaft 57 as an inner member and a nut member 59 as an outer member attached to the screw shaft 57 so as to be relatively rotatable via a plurality of balls 58. .

The screw shaft 57 is an inward member in which rolling element rolling grooves 57a as a helical raceway surface are formed on the outer peripheral surface, while the nut member 59 corresponds to the rolling element rolling grooves 57a on the inner peripheral surface. Load rolling groove as a helical raceway surface. The nut member 59 can reciprocate relative to the screw shaft 57 in accordance with the relative rotational movement of the screw shaft 57 with respect to the nut member 59.

Then, for at least one of the rolling element rolling groove 57a of the screw shaft 57, the load rolling groove of the nut member 59, and the ball 58 constituting the ball screw device 56, the above-described underlayer 12 and functional layer 13 Coating layer can be formed. With this configuration, metal contact on the rolling element rolling groove 57a of the screw shaft 57, the load rolling groove of the nut member 59, and the ball 58 that will receive repeated rolling load is prevented, and the ball screw device 56 is worn out. It is possible to improve the characteristics and the lubrication life characteristics.

(Example of application to spline device)
Furthermore, the rolling device according to the present embodiment can be configured as, for example, a spline device 60 as shown in FIG. FIG. 9 is a view illustrating the case where the rolling device according to the present embodiment is configured as a spline device.

Here, the configuration of the spline device 60 shown in FIG. 9 will be briefly described. The spline device 60 includes a spline shaft 61 as an inward member and balls 62 as many rolling elements on the spline shaft 61. It has a cylindrical outer cylinder 63 as an outward member movably attached. On the surface of the spline shaft 61, a rolling element rolling surface 61a is formed as a raceway surface which becomes a track of the ball 62 and extends in the axial direction of the spline shaft 21. In the outer cylinder 63 attached to the spline shaft 61, a load rolling element rolling surface as a raceway surface corresponding to the rolling element rolling surface 61a is formed. On these load rolling element rolling surfaces, a plurality of strips of protrusions extending in the direction in which the rolling element rolling surfaces 61a extend are formed. A load rolling path is formed between the load rolling element rolling surface formed on the outer cylinder 63 and the rolling element rolling surface 61 a formed on the spline shaft 61. Next to the load rolling path, a no-load return path is formed to move the ball 62 released from the load. The outer cylinder 63 incorporates a holder 64 that aligns and holds the plurality of balls 62 in a circuit shape. Then, a plurality of balls 62 are rotatably installed between the load rolling element rolling surface of the outer cylinder 63 and the rolling element rolling surface 61 a of the spline shaft 61, and circulate endlessly through the no load return passage. The outer cylinder 63 can be reciprocated relative to the spline shaft 61 by being installed as described above.

Also in the case of the spline device 60 shown in FIG. 9, at least one of the rolling element rolling surface 61 a of the spline shaft 61 constituting the spline device 60 and the load rolling element rolling surface of the outer cylinder 63 and the balls 62. On the other hand, the coating layer which consists of base layer 12 and functional layer 13 which were mentioned above can be formed. With this configuration, metal contact on the rolling element rolling surface 61a of the spline shaft 61, the load rolling element rolling surface of the outer cylinder 63, and the balls 62 that will receive repeated rolling loads can be prevented. It becomes possible to improve wear characteristics and lubrication life characteristics.

(Example of application to rotary bearing device)
Furthermore, the rolling device according to the present embodiment can be configured, for example, as a rotating bearing device 70 as shown in FIGS. 10 and 11. Here, FIG. 10 is a partial vertical perspective view illustrating an embodiment in which the rolling device according to the present embodiment is configured as a rotating bearing device. 11 is a longitudinal sectional view of the rotary bearing device shown in FIG.

As shown in FIGS. 10 and 11, the rolling device configured as the rotating bearing device 70 has an inner race surface 72 (as an inner member or an outer member) having an inner raceway surface 72 having a V-shaped cross section on the outer peripheral surface. And an outer race 73 (as an outer member or an inner member) having an outer raceway surface 74 having a V-shaped cross section on the inner peripheral surface, and a substantially rectangular cross section formed by the inner raceway surface 72 and the outer raceway surface 74 The inner ring 71 and the outer ring 73 perform relative rotational movement in the circumferential direction by having a plurality of rollers 77 as rolling elements cross arranged in a rollable manner between the track paths 75.

Also in such a rotary bearing device 70, at least one of the inner raceway surface 72 of the inner ring 71 and the outer raceway surface 74 of the outer ring 73 of the rotary bearing device 70 and the roller 77 A coating layer composed of the functional layer 13 can be formed. With this configuration, metal contact on the inner raceway surface 72 of the inner ring 71 and the outer raceway surface 74 of the outer race 73 and the roller 77 that will receive repeated rolling loads can be prevented, and the wear characteristics and lubrication life of the rotary bearing device 70 It is possible to improve the characteristics.

(Example of application to slide screw device)
About each apparatus mentioned above, the apparatus of the form by which the several rolling element was interposed between the inward member and the outward member was illustrated and demonstrated. However, the application range of the present invention characterized in that a coating layer is formed on a component of a rolling device is not limited to the one using such a rolling element, and the inward member and the rolling member are not used. It is possible to use suitably also to the device constituted by direct contact with the outer member and capable of relative movement.

For example, as shown in FIG. 12, the present invention can be applied to a rolling device configured as a slide screw device 80. Here, FIG. 12 is an external appearance perspective view which illustrates one form at the time of comprising the rolling device which concerns on this embodiment as a sliding screw apparatus. The slide screw device 80 shown in FIG. 12 has a screw shaft 81 as an inward member in which a screw groove as a helical raceway surface is formed on the outer peripheral surface, and a spiral shape corresponding to the screw groove on the inner peripheral surface. By having a nut member 83 as an outward member in which a nut groove as a raceway surface is formed, the nut member 83 is attached to the screw shaft 81 in accordance with the relative rotational movement of the screw shaft 81 with respect to the nut member 83. It is configured to be able to reciprocate relative to it.

And also about the slide screw apparatus 80 shown in FIG. 12, the coating layer which consists of the foundation layer 12 mentioned above and the functional layer 13 is formed with respect to the screw groove of the screw shaft 81 which is the component, and the nut groove of the nut member 83. can do. With such a configuration, metal contact in the screw groove of the screw shaft 81 and the nut groove of the nut member 83 which will be subjected to repeated sliding loads can be prevented, and the wear characteristics and lubrication life characteristics of the slide screw device 80 can be improved. It becomes possible.

As mentioned above, although the suitable embodiment of the present invention was described, the technical scope of the present invention is not limited to the range given in the above-mentioned embodiment. It is possible to add various change or improvement to the above-mentioned embodiment.

For example, the present invention can be applied to a rolling device 90 of a type in which a linear motion guide and a ball screw are combined to form an integral structure as shown in FIG. In the case of the rolling device 90 shown in FIG. 13, although the screw shaft 91 and the moving block 93 are installed via the plurality of balls 95, the screw shaft 91 and the moving block are not performed via the plurality of balls 95. It is also possible that 93 is configured as a slide screw.

It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

The rolling device according to the present invention described above has various industrial applicability. For example, in the technical fields related to nuclear energy and energy, rolling devices may be used in a radiation exposure environment, but oil and resin are decomposed by radiation, and the decomposed substances become pollutants. However, by using the coating layer according to the present invention for the rolling device, oil-free can be realized, and according to the present invention, the rolling device can be suitably used even in a radiation exposure environment. It is possible to

Also, for example, in the case of the rolling and sliding movement in which the rolling movement and sliding movement are performed at a low speed and under a high load, formation of an oil film becomes difficult and wear progresses in a conventional lubricant using oil or grease A challenge existed. However, by using the coating layer according to the present invention for the rolling device, oil-free can be realized, so it is possible to provide a rolling device effective for use conditions under low speed and high load.

Also, for example, in the technical field in the space and aerospace industry, the use of a rolling device in a cryogenic environment is required, but with a conventional oil or grease lubricant, torque is increased due to the increase in viscous drag at low temperatures. There was a problem of getting higher. However, by using the coating layer according to the present invention for the rolling device, oil-free can be realized, so that the difference in frictional resistance due to temperature disappears, and it can be suitably used under any temperature condition. A dynamic device can be provided.

Further, for example, in the technical field of food manufacturing machinery and medical devices, there has been a problem that when using conventional oils and greases, they have to be sensitive to lubricant leakage and dripping. However, by using the coating layer according to the present invention for the rolling device, oil-free can be realized, so the rolling device can be used safely even in an environment sensitive to lubricant leakage and dripping. It is possible to provide

Further, for example, in the case of a use environment where vibration is added to the rolling device, there has been a problem that the formation of an oil film becomes difficult with a conventional lubricant using oil or grease, and wear progresses. However, since the metal contact can be prevented by using the coating layer according to the present invention for the rolling device, it is possible to provide the rolling device effective for the use environment where vibration is added.

As described above, the application range of the rolling device is greatly expanded by using the coating layer according to the present invention for the rolling device.

DESCRIPTION OF SYMBOLS 11 base material, 12 foundation layer, 13 functional layer, 40 linear guide apparatus, 41 track rail, 41a rolling element rolling surface, 42 ball, 43 moving block, 43a load rolling element rolling surface, 48, 49 screw hole, 52 Load rolling path, 53 no-load rolling path, 55 direction changing path, 56 ball screw device, 57 screw shaft, 57a rolling element rolling groove, 58 ball, 59 nut member, 60 spline device, 61 spline shaft, 61a rolling element rolling Running surface, 62 ball, 63 outer cylinder, 64 cage, 70 rotary bearing device, 71 inner ring, 72 inner raceway surface, 73 outer race ring, 74 outer raceway surface, 75 raceway, 77 roller, 80 slide screw device, 81 screw shaft , 83 nut member, 90 rolling device, 91 screw shaft, 93 moving block, 95 ball.

Claims

An inner member having a raceway surface on the outer surface,
An outer member disposed on the outer side of the inner member, the outer member having a raceway surface opposite to the raceway surface of the inner member;
A rolling element disposed rotatably between the two raceways;
In a rolling device provided with
At least one of a raceway surface of the inner member, a raceway surface of the outer member, and the rolling elements is
A base material made of a metallic material,
An underlayer formed on the surface side of the base material;
A functional layer formed on the surface side of the underlayer;
Is composed of
The functional layer is configured as a composite layer having a laminated structure in which WC layers and C layers are alternately laminated,
The outermost surface of the composite layer which comprises the said functional layer is comprised by C layer, The rolling device characterized by the above-mentioned.
In the rolling device according to claim 1,
The W (tungsten) composition ratio of the WC layer constituting the functional layer is
0% by weight <W ≦ 30% by weight
A rolling device characterized by satisfying the following inequality.
In the rolling device according to claim 1 or 2,
The underlayer is made of W (tungsten),
A rolling device characterized in that a connection surface of the functional layer with the base layer is constituted by a WC layer.
In the rolling device according to claim 1 or 2,
The base layer is configured so that the main component is W (tungsten), and the C component is gradually increased from the connection surface with the base material toward the connection surface with the functional layer. ,
A rolling device characterized in that a connection surface of the functional layer with the base layer is constituted by a WC layer.
In the rolling device according to claim 1 or 2,
A rolling device characterized in that a Vickers hardness Hv of a composite layer constituting the functional layer is 800 to 1,500.
In the rolling device according to claim 1 or 2,
A rolling device characterized in that the hardness value of the composite layer constituting the functional layer performed by a nano indenter is 12 GPa to 17 GPa.
In the rolling device according to claim 1,
The coating film of the C layer, which is the outermost surface of the composite layer constituting the functional layer, is configured to increase the coating hardness from the connection surface with the base material in the base layer toward the surface of the functional layer A rolling device characterized in that the hardness decreases gradually towards the surface.