Plate spring and bearing

Abstract

To realize a plate spring which makes proper surface contact between an outer ring and an inner ring in a bearing.SOLUTION: A plate spring is provided at a bearing (1) including an outer ring (11) and an inner ring (12) and includes: a ring shaped first ring (16) provided in the outer ring; and a ring shaped second ring (17) is provided in the inner ring and has a common center axis with the first ring. The first ring has a first slide part (23) and a first attachment part (21). The second ring has a second slide part (33) and a second attachment part (31). At least one of the first attachment part and the first slide part or the second attachment part and the second slide part are connected by three or more flexible spring parts.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a leaf spring for use in a bearing. [Background technology]

[0002] In a device having a rotating part, a bearing is provided between a fixed part and the rotating part. Patent Document 1 discloses a technology for establishing electrical continuity between an outer ring and an inner ring in this bearing by using a conductive seal part.

[0003] Furthermore, Patent Document 2 discloses a condition measuring device for use with bearings that generates electricity using friction caused by relative motion between a fixed part and a rotating part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-139251 [Patent Document 2] JP 2019-152565 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, the contact between the outer ring and the seal portion and the inner ring and the seal portion is line contact, so the conductive seal portion is prone to wear, and as a result, there is a possibility that stable contact cannot be obtained.

[0006] An object of one aspect of the present invention is to provide a leaf spring that can achieve appropriate surface contact between an outer ring and an inner ring in a bearing. [Means for solving the problem]

[0007] In order to solve the above problems, the leaf spring of the present invention is a leaf spring provided in a bearing having a first wheel and a second wheel sharing a central axis with the first wheel, and includes a ring-shaped first ring provided for the first wheel and a ring-shaped second ring provided for the second wheel and sharing a central axis with the first ring, the first ring has a first sliding part and a first mounting part attached to the first wheel, the second ring has a second sliding part that slides against the first sliding part and a second mounting part attached to the second wheel, and at least one of the first mounting part and the first sliding part or the second mounting part and the second sliding part are connected to each other by three or more flexible spring parts.

[0008] In order to solve the above problems, the leaf spring of the present invention comprises: a first ring having a ring shape attached to a fixed part; and a second ring having a ring shape attached to a rotating part that rotates relative to the fixed part and shares a central axis with the first ring, wherein the first ring has a first sliding part and a first mounting part attached to the fixed part, and the second ring has a second sliding part that slides relative to the first sliding part and a second mounting part attached to the rotating part, and at least one of the first mounting part and the first sliding part or the second mounting part and the second sliding part are connected to each other by three or more flexible spring parts.

[0009] In order to solve the above problems, the bearing of the present invention comprises a first wheel, a second wheel sharing a central axis with the first wheel, a first ring fixed to the first wheel, and a second ring fixed to the second wheel and having an area in contact with the first ring, wherein a conductive DLC is formed in at least one band-shaped area of ​​the contact surface between the first ring and the second ring. Effect of the Invention

[0010] According to the present invention, the outer ring and the inner ring of the bearing can be in appropriate surface contact at the first sliding portion and the second sliding portion. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a configuration of a bearing according to a first embodiment. [Diagram 2] 1 is a partial cross-sectional view of a bearing according to a first embodiment. [Diagram 3] 3 is an enlarged view of the first ring and the second ring in FIG. 2 according to the first embodiment. FIG. [Figure 4] FIG. 2 is a front view of a first ring according to the first embodiment. [Diagram 5] FIG. 2 is a front view of a second ring according to the first embodiment. [Figure 6] 13 is a graph plotting axial forces that influence each other with respect to the displacement of a first flexible spring portion and a second flexible spring portion. [Figure 7] 3 is a graph showing the electrical conductivity of the bearing 1. [Figure 8] 6 is a schematic diagram illustrating a flat spring according to a second embodiment. FIG. [Figure 9] FIG. 11 is a front view of a first ring according to a third embodiment. [Figure 10] 4 is a graph showing frequency characteristics of the bearing according to the first embodiment. [Figure 11] FIG. 11 is an enlarged view of the first ring and the second ring according to the fourth embodiment. [Figure 12] FIG. 11 is a perspective view showing the configuration of a bearing according to embodiment 5. [Figure 13] FIG. 11 is a front view of a first electrode according to embodiment 5. [Figure 14] FIG. 13 is a front view of a second electrode according to embodiment 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Embodiment 1] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0013] (Structure of bearing 1) Fig. 1 is a perspective view showing the configuration of a bearing 1 according to embodiment 1. Fig. 2 is a partial cross-sectional view of the bearing 1 according to embodiment 1. The bearing 1 is a so-called bearing that is provided between a fixed part and a rotating part, holds the rotating part in a correct position relative to the fixed part, and reduces friction in the rotational motion of the rotating part relative to the fixed part.

[0014] As shown in Figures 1 and 2, the bearing 1 comprises an outer ring (first ring) 11, an inner ring (second ring) 12, a rolling element 13, a retainer 14, a sealing portion 15, a first ring 16, and a second ring 17.

[0015] The outer ring 11 and the inner ring 12 share a central axis C and rotate relative to each other. One of the outer ring 11 and the inner ring 12 is provided on a fixed part, and the other is provided on a rotating part. The diameter of the outer ring 11 is larger than the diameter of the inner ring 12. Both the outer ring 11 and the inner ring 12 have a ring-like shape.

[0016] The rolling elements 13 are spheres, and rotate while in contact with a recess formed on the inner circumference of the outer ring 11 and a recess formed on the outer circumference of the inner ring 12. A plurality of rolling elements 13 are provided in the bearing 1. In order to arrange the rolling elements 13 at equal intervals, a cage 14 is provided that maintains the relative positions of the rolling elements 13.

[0017] The rolling element 13 maintains rotation by contacting the outer ring 11 and the inner ring 12. Therefore, frictional contact occurs between the outer ring 11 and the rolling element 13, and between the inner ring 12 and the rolling element 13. Grease (not shown) is added to reduce this frictional contact. A pair of sealing portions 15 is provided to prevent leakage of the grease. The sealing portions 15 are fitted slidably into the outer ring 11 and the inner ring 12. In other words, grease is filled between the pair of sealing portions 15, and the grease ensures smooth rotation of the rolling element 13.

[0018] (1st Ring 16 and 2nd Ring 17) Fig. 3 is an enlarged view of the first ring 16 and the second ring 17 in Fig. 2 according to embodiment 1. Fig. 4 is a front view of the first ring 16 according to embodiment 1. Fig. 5 is a front view of the second ring 17 according to embodiment 1.

[0019] 4, the first ring 16 includes a first attachment portion 21, a plurality of first flexible spring portions (flexible spring portions) 22, and a first sliding portion 23. In addition, a plurality of gaps 24 are formed as spaces where the first ring 16 is not formed. The first ring 16 is provided on the outer ring 11 and has a ring shape.

[0020] The first attachment portion 21 is a portion that comes into contact with the outer ring 11 and is fitted (fixed) to the outer ring 11. The first attachment portion 21 may be adhered to the outer ring 11. The first attachment portion 21 is formed in a ring shape.

[0021] The first sliding portion 23 is a portion that comes into contact with the second ring 17. The first sliding portion 23 is formed in a ring shape. The diameter of the first sliding portion 23 is smaller than the diameter of the first attachment portion 21.

[0022] The first flexible spring portion 22 is a plurality of thin flat springs that connect the first mounting portion 21 and the first sliding portion 23. At least three first flexible spring portions 22 may be provided. A gap 24 is formed so that the first flexible spring portion 22 can act as a thin flat spring. The gap 24 allows the first sliding portion 23 to float and be displaced relative to the first mounting portion 21. Even when the first sliding portion 23 floats relative to the first mounting portion 21, the first flexible spring portion 22 connects them to each other.

[0023] 5, the second ring 17 includes a second attachment portion 31, a plurality of second flexible spring portions (flexible spring portions) 32, and a second sliding portion 33. In addition, a plurality of gaps 34 are formed as spaces where the second ring 17 is not formed. The second ring 17 is provided on the inner ring 12, shares a central axis C with the first ring 16, and is ring-shaped.

[0024] The second attachment portion 31 is a portion that comes into contact with the inner ring 12 and is fitted (fixed) to the inner ring 12. The second attachment portion 31 may be adhered to the inner ring 12. The second attachment portion 31 is formed in a ring shape.

[0025] The second sliding portion 33 is a portion that comes into contact with the first ring 16. The second sliding portion 33 is formed in a ring shape. The diameter of the second sliding portion 33 is larger than the diameter of the second attachment portion 31.

[0026] The second flexible spring portion 32 is a plurality of thin flat springs that connect the second mounting portion 31 and the second sliding portion 33. At least three second flexible spring portions 32 may be provided. A gap 34 is formed so that the second flexible spring portion 32 can act as a thin flat spring. The gap 34 allows the second sliding portion 33 to float and be displaced relative to the second mounting portion 31. Even when the second sliding portion 33 floats relative to the second mounting portion 31, the second flexible spring portion 32 connects them to each other.

[0027] A conductive DLC (Diamond like carbon) may be formed in a strip-shaped region of at least one of the first ring 16 and the second ring 17. That is, as shown in FIG. 3, a conductive DLC film 25 is formed on the first ring 16, and a conductive DLC film 35 is formed on the second ring 17. Here, the strip-shaped region is a region having a width with respect to the extending direction. In the present embodiment, the extending direction is the circumferential direction.

[0028] The first ring 16 and the second ring 17 are conductors such as metal and may have conductivity. Therefore, the first ring 16 and the second ring 17 on which the conductive DLC films are formed are electrically connected by contacting each other at the first sliding portion 23 and the second sliding portion 33. Note that this contact may be made via the conductive DLC film 25 and the conductive DLC film 35.

[0029] The outer diameter d1 of the first sliding portion 23 is preferably equal to or larger than the outer diameter d2 of the second sliding portion 33. Also, the inner diameter d3 of the first sliding portion 23 is preferably equal to or larger than the inner diameter d4 of the second sliding portion 33. That is, the relationship of d4≦d3<d2≦d1 exists between the first sliding portion 23 and the second sliding portion 33. This is because when the center of the first ring 16 is displaced and fixed from the center of the outer ring 11, and when the center of the second ring 17 is displaced and fixed from the center of the inner ring 12, the centers of the first sliding portion 23 and the second sliding portion 33 are displaced from each other. Even in this case, this is to prevent the first sliding portion 23 from contacting the second flexible spring portion 32 and to prevent the second sliding portion 33 from contacting the first flexible spring portion 22.

[0030] (The first flexible spring portion 22 and the second flexible spring portion 32) As shown in Figs. 4 and 5, at least one of the first flexible spring portion 22 and the second flexible spring portion 32 is formed in an arc shape. When the first sliding portion 23 and the second sliding portion 33 come into contact with each other, a force (axial force) in the extension direction of the bearing 1 is applied to the first flexible spring portion 22 and the second flexible spring portion 32, and the first flexible spring portion 22 and the second flexible spring portion 32 are deformed. Since the first flexible spring portion 22 and the second flexible spring portion 32 are at least three or more thin flat springs, a plane can be formed by three points. Therefore, the planes can maintain contact with each other. In other words, the first flexible spring portion 22 and the second flexible spring portion 32 come into contact with each other with uniform pressure.

[0031] Fig. 6 is a graph plotting the axial forces that affect each other against the displacement of the first flexible spring portion 22 and the second flexible spring portion 32. As shown in Fig. 6, there is a linear relationship between the displacement (deformation amount) in the extension direction (direction of the axial force) of the bearing 1 and the axial force. This is because the first ring 16 and the second ring 17 are made of metal, and therefore there is a linear relationship between the displacement and the axial force in the elastic region.

[0032] Here, since the sealing portion, which is the conductive member in Patent Document 1, is made of rubber, a linear relationship cannot be obtained between the displacement and the axial force. In addition, since rubber behaves nonlinearly with respect to temperature, it is difficult to control the degree of contact by the sealing portion.

[0033] In contrast, in this embodiment, as shown in FIG. 6, there is a linear relationship between the displacement and the axial force, which has the advantage that the magnitude of the friction force caused by the contact between the first sliding portion 23 and the second sliding portion 33 can be easily designed.

[0034] Here, as shown in Fig. 3, an axial force corresponding to the sum of their respective displacements is generated in the first flexible spring portion 22 and the second flexible spring portion 32. Therefore, if the thickness of the first ring 16 and the second ring 17 is 0.1 [mm], for example, it can be seen from Fig. 6 that the axial force is a very small value of 27 [mN]. Since the frictional force is a value obtained by multiplying the axial force by the friction coefficient, low friction can be achieved and rotation is not hindered.

[0035] Furthermore, the first flexible spring portion 22 and the second flexible spring portion 32 are formed in an arc shape, and therefore have high rigidity in the rotational direction.

[0036] (Conductive) Here, with high-voltage components, there is a greater need to prevent electromagnetic interference between the components. As the number of high-voltage components increases, the electromagnetic interference between the components also increases. If the electromagnetic interference propagates to electronic devices, it may adversely affect the operation of the devices as electromagnetic noise. Therefore, devices that use high-voltage components need to take measures against electromagnetic noise. Therefore, in devices that have high-voltage components and a rotating part, it may be necessary to take measures against electromagnetic noise by grounding (conducting) the fixed part and the rotating part to each other.

[0037] For this reason, electrical continuity is sometimes ensured by bearings. Patent Document 1 is one example of this. In Patent Document 1, electrical continuity between the outer ring and the inner ring is ensured by linear conductive DLC formed in the conductive rubber seal. However, because it is linear contact, stress tends to concentrate and it is prone to degradation due to wear caused by friction.

[0038] In contrast, in this embodiment, contact between the first sliding portion 23 and the second sliding portion 33 can be achieved with uniform stress due to the surfaces of the first flexible spring portion 22 and the second flexible spring portion 32, thereby suppressing wear due to friction.

[0039] Fig. 7 is a graph showing the electrical conductivity of bearing 1. The graph in Fig. 7 compares bearing 1 with comparative example 100 in which first ring 16 and second ring 17 are removed from bearing 1. A conductive DLC film 25 is formed on first ring 16 in bearing 1, and a conductive DLC film 35 is formed on second ring 17. Note that Fig. 7 measures the electrical resistance between outer ring 11 and inner ring 12 as the rotation speed changes.

[0040] 7, bearing 1 achieves nearly 0 [Ω] at any rotation speed, but comparative example 100 exhibits a large electrical resistance. This indicates that it is difficult for rolling elements 13 to establish electrical continuity between outer ring 11 and inner ring 12.

[0041] When electromagnetic noise occurs in a bearing 100 having a large electrical resistance, as in the comparative example, the rolling elements 13 and the like may be burned. As a result, the rolling elements may deteriorate and the rotation performance may deteriorate. This phenomenon is called electrical corrosion.

[0042] In contrast, the bearing 1 has low electrical resistance, so that electrolytic corrosion can be prevented even in an electromagnetic noise environment. Therefore, the bearing 1 is a highly reliable bearing even in adverse environments.

[0043] (Conductive DLC) A conductive DLC film is formed on a strip-shaped region of at least one of the first ring 16 and the second ring 17. The conductive DLC has a low coefficient of friction and excellent wear resistance. In addition, it has low mating attack, chemical inertness, and corrosion resistance. Therefore, even if the first sliding part 23 and the second sliding part 33 directly contact each other and slide, their states do not change and smooth rotation can be maintained.

[0044] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0045] In the first embodiment, the bearing 1 includes the first ring 16 and the second ring 17, but in the second embodiment, the first ring 16 and the second ring 17 are provided in the fixed portion and the rotating portion.

[0046] FIG. 8 is a schematic diagram illustrating a leaf spring 18 according to a second embodiment. The leaf spring 18 includes a first ring 16 and a second ring 17. As shown in FIG. 8, a bearing 2 is disposed in a housing 51, which is a fixed part, and a shaft 50, which is a rotating part, is supported by the bearing 2. The leaf spring 18 is provided between the bearing 2, the housing 51, and the shaft 50. An appropriate axial force is applied to the leaf spring 18 by a clamp 52 provided in the fixed part or the rotating part. Note that, in FIG. 8, the clamp 52 is provided in both the fixed part and the rotating part, but it may be provided in only one of them. The clamp 52 is separate for the fixed part and the rotating part.

[0047] The leaf spring 18 is composed of a first ring 16 that contacts the outer ring 11 of the bearing 2, and a second ring 17 that contacts the inner ring 12 of the bearing 2. In other words, the leaf spring 18 is disposed in contact with the bearing 2 that supports the space between the fixed part and the rotating part.

[0048] The leaf spring 18 can ensure electrical continuity between the fixed part and the rotating part, and can prevent electrolytic corrosion. In particular, since electrolytic corrosion can be prevented simply by adding the leaf spring 18, it is easy to implement in existing equipment.

[0049] Here, the position at which the leaf spring 18 is disposed does not need to be in contact with the bearing 2, but may be disposed so as to be in contact with any position between the fixed portion and the rotating portion.

[0050] [Embodiment 3] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0051] In the first embodiment, the first sliding part 23 and the second sliding part 33 are formed in a ring shape without a cavity. In the third embodiment, at least one of the first sliding part 23 and the second sliding part 33 has a cavity (hole) in the ring.

[0052] 9 is a front view of the first ring 16a according to embodiment 3. The first ring 16a has at least one hole 26 in the first sliding portion 23 of the first ring 16. The shape of the hole 26 may be circular or may be another shape, such as a rectangle, a polygon, or a slit.

[0053] The hole 26 is not limited to be provided in the first sliding part 23, and may be provided in the second sliding part 33. Also, the first sliding part 23 may not have the hole 26, and only the second sliding part 33 may have the hole 26. In other words, at least one of the first sliding part 23 and the second sliding part 33 may have at least one hole 26.

[0054] 10 is a graph showing the frequency characteristics of the bearing 1 according to the first embodiment. As shown in FIG. 10, it can be seen that the bearing 1 without the hole 26 resonates at, for example, 197 Hz. Therefore, it is necessary to use the bearing 1 while avoiding frequencies around this frequency. In other words, the usable rotation speed is limited. The natural frequency at which this resonance occurs is determined depending on the masses of the first sliding portion 23 and the second sliding portion 33.

[0055] In contrast, in this embodiment, since the hole 26 is provided, at least one of the first sliding part 23 and the second sliding part 33 has a small mass. Therefore, the natural frequency at which resonance occurs can be increased, and the upper limit of the rotation speed at which the first ring 16a and the second ring 17 can be used can be raised.

[0056] [Embodiment 4] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0057] In the first embodiment, the first sliding portion 23 and the second sliding portion 33 are flat. In the fourth embodiment, at least one of the first sliding portion 23 and the second sliding portion 33 has projections and recesses.

[0058] 11 is an enlarged view of the first ring 16b and the second ring 17 according to the fourth embodiment. The first ring 16b has an uneven portion 27 in the region of the first sliding portion 23b where the second sliding portion 33 comes into contact. The uneven portion 27 can have various uneven shapes. For example, it may have dot-shaped unevenness, linear unevenness extending in the arc direction, etc. A conductive DLC film 25 may be formed on the surface of the uneven portion 27.

[0059] The concave-convex portion 27 may be formed by processing the concave-convex portion by pressing, sandblasting, wet etching, or the like when molding the first ring 16b. After the concave-convex portion is processed, the surface of the first ring 16b is coated with DLC. That is, the coating is formed on the concave-convex portion 27 as well.

[0060] The uneven portion 27 is not limited to the first sliding portion 23, and may also be present in the second sliding portion 33. Also, the first sliding portion 23 may not have the uneven portion 27, and only the second sliding portion 33 may have the uneven portion 27. In other words, at least one of the first sliding portion 23 and the second sliding portion 33 may have at least one uneven portion 27.

[0061] The first sliding portion 23 and the second sliding portion 33 of the bearing 1 according to the first embodiment are flat surfaces that come into contact with each other. It is known that when flat surfaces are brought into contact with each other, if moisture is present between the flat surfaces, a meniscus force is generated. Therefore, when the flat surfaces are brought into contact with each other, they may be attracted to each other and bonded together.

[0062] In contrast, in this embodiment, since the uneven portion 27 is provided, at least one of the first sliding portion 23 and the second sliding portion 33 is uneven rather than flat. Therefore, moisture present between them is located in the concave portion of the unevenness, and moisture is not located between the contacting flat surfaces. As a result, it is possible to prevent the first sliding portion 23 and the second sliding portion 33 from bonding. That is, the leaf spring in this embodiment can reduce the frictional resistance and the meniscus force, so it can be used even when the bearing rotates at high speed.

[0063] [Embodiment 5] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0064] In the fifth embodiment, a conductive pattern may be formed on the first sliding portion 23 and the second sliding portion 33. In this embodiment, frictional power generation using the conductive pattern accompanying rotation as shown in Patent Document 2 is performed in the first sliding portion 23 and the second sliding portion 33.

[0065] 12 is a perspective view showing the configuration of a bearing 3 according to embodiment 5. The bearing 3 includes an outer ring (first ring) 11, an inner ring (second ring) 12, a rolling element 13, a cage 14 (not shown), a first ring 16, a second ring 17, a first electrode 60, and a second electrode 70. A sealing portion 15 may also be included. The bearing 3 according to embodiment 5 differs from embodiment 1 in that it includes the first electrode 60 and the second electrode 70. In addition, the first ring 16 and the second ring 17 do not have to be formed with conductive DLC.

[0066] 13 is a front view of the first electrode 60 according to the fifth embodiment. The first electrode 60 is a divided conductive pattern provided on the first sliding portion 23 of the first ring 16. The first electrode 60 is a conductive pattern divided in the circumferential direction, and two-pole conductive patterns 63a and 63b are alternately arranged. Output terminals 63c and 63d are provided from each of the conductive patterns 63a and 63b. The conductive patterns 63a and 63b have the same size and pitch and are arranged at equal intervals.

[0067] 14 is a front view of the second electrode 70 according to the fifth embodiment. The second electrode 70 is a divided conductive pattern provided on the second sliding portion 33 of the second ring 17. In the second electrode 70, charged layers 78a and insulating portions 77 are alternately arranged in the circumferential direction. The charged layers 78a may be a conductive pattern. The charged layers 78a have the same size and are arranged at equal intervals. The number of charged layers 78a is equal to the number of conductive patterns 63a and 63b.

[0068] The first electrode 60 and the second electrode 70 do not have to be formed separately from the first ring 16 and the second ring 17, and may be formed integrally with them. That is, the first electrode 60 only needs to be formed on the first sliding portion 23 of the first ring 16. The second electrode 70 only needs to be formed on the second sliding portion 33 of the second ring 17. The first electrode 60 and the second electrode 70 may be formed interchangeably. Of the first electrode 60 and the second electrode 70, the electrode on the fixed portion side functions as a stator electrode, and the electrode on the rotating portion side functions as a rotor electrode.

[0069] The first electrode 60 and the second electrode 70 come into contact with each other and slide against each other. That is, they rub against each other. Therefore, in order to improve wear resistance and the like, DLC may be formed on the first electrode 60 and the second electrode 70, respectively. Note that it is preferable that the DLC formed is non-conductive. In this case, an analog voltage is generated between the first electrode 60 and the second electrode 70 by frictional power generation, and can be used to measure various state quantities.

[0070] The DLC formed on the first electrode 60 may be different from that formed on the second electrode 70. For example, a fluorine-containing DLC ​​is formed on the first electrode 60, and a hydrogen-containing DLC ​​is formed on the second electrode 70. Furthermore, a charged film may be laminated on either the first electrode 60 or the second electrode 70. The charged film is charged by sliding, and a voltage is generated between the first electrode 60 and the second electrode 70.

[0071] The DLC to be formed may be conductive DLC. In this case, for example, by applying a voltage to one of the first electrodes 60 and measuring the other electrode, a pulse can be generated and used as an encoder. Also, by configuring the first electrode 60 with three poles, it can be used as an encoder that supports forward and reverse rotation.

[0072] In this embodiment, the first ring 16 and the second ring 17 are not limited to being made of metal. For example, they may be made of a combination of materials that tend to be easily charged with electricity.

[0073] [Modifications] (Thrust bearing) Although the first to fifth embodiments have been described with reference to a radial bearing, the first ring 16 and the second ring 17 are not limited to being provided on a radial bearing. For example, the first ring 16 and the second ring 17 may be provided on a thrust bearing. In the case of a thrust bearing, the first ring 16 and the second ring 17 are provided as leaf springs between a shaft washer (first ring) and a housing washer (second ring).

[0074] (Shape of flexible spring part) The first flexible spring portion 22 and the second flexible spring portion 32 are formed in an arc direction so as to rotate in one direction, but this is not limited thereto. For example, they may be formed in an arc direction with the rotation directions alternated.

[0075] (Number of leaf springs) In the first to fifth embodiments, the first flexible spring portion 22 and the second flexible spring portion 32 are described as being provided, but this is not a limitation. It is sufficient to provide at least one of the first flexible spring portion 22 or the second flexible spring portion 32. Even in this case, the first ring 16 and the second ring 17 contact each other via the first sliding portion 23 and the second sliding portion 33, and electrical continuity can be ensured. By providing three or more first flexible spring portions 22 or three or more second flexible spring portions 32, uniform pressure can be applied and stable contact and sliding can be ensured.

[0076] In other words, at least one of the first mounting portion 21 and the first sliding portion 23, or the second mounting portion 31 and the second sliding portion 33, may be connected to each other by flexible spring portions that are three or more thin flat springs.

[0077] 〔summary〕 A leaf spring according to a first aspect of the present invention is a leaf spring mounted on a bearing including a first wheel and a second wheel sharing a central axis with the first wheel, the leaf spring comprising a first ring-shaped first ring mounted on the first wheel and a second ring-shaped second ring mounted on the second wheel and sharing a central axis with the first ring, the first ring having a first sliding portion and a first mounting portion mounted on the first wheel, the second ring having a second sliding portion sliding against the first sliding portion and a second mounting portion mounted on the second wheel, and at least one of the first mounting portion and the first sliding portion or the second mounting portion and the second sliding portion are connected to each other by three or more flexible spring portions.

[0078] According to the above configuration, the first and second wheels of the bearing can be in surface contact at the first sliding portion and the second sliding portion with a simple structure. That is, the leaf spring of this configuration can apply pressure uniformly and ensure stable contact sliding. Therefore, vibration can be reduced even when the bearing rotates at high speed. In addition, mass production is easy.

[0079] A leaf spring according to a second aspect of the present invention is the leaf spring of the first aspect, wherein the first ring and the second ring are electrically conductive.

[0080] According to the above configuration, electrical continuity between the first wheel and the second wheel can be ensured.

[0081] The leaf spring according to the third aspect of the present invention may be configured as in the first or second aspect above, wherein a conductive DLC (Diamond-like carbon) is formed in a strip-shaped region of at least one of the contact surfaces of the first sliding portion and the second sliding portion.

[0082] According to the above-mentioned configuration, it is possible to improve the wear resistance of the first sliding portion and the second sliding portion. Furthermore, since electrical conductivity can be ensured, it is possible to prevent electrolytic corrosion.

[0083] The leaf spring according to aspect 4 of the present invention may be configured as in any one of aspects 1 to 3 above, such that the diameter of the first sliding portion is smaller than the diameter of the first mounting portion, the diameter of the second sliding portion is larger than the diameter of the second mounting portion, and the diameter of the first sliding portion is equal to or larger than the diameter of the second sliding portion.

[0084] According to the above configuration, even if the rotation axis is slightly misaligned, the first sliding portion and the second sliding portion do not interfere with the flexible spring portion, thereby achieving stable surface contact.

[0085] A leaf spring according to a fifth aspect of the present invention is the leaf spring of any one of the first to fourth aspects, wherein the flexible spring portion is formed in an arc shape.

[0086] According to the above configuration, the flexible spring portion exhibits high rigidity against a load in the rotational direction, and therefore, stable surface contact can be achieved even when the flexible spring portion is provided in a location that is rotating for a long period of time.

[0087] A leaf spring according to a sixth aspect of the present invention is the leaf spring of any one of the first to fifth aspects, wherein at least one of the first sliding portion and the second sliding portion may have a hole.

[0088] According to the above-mentioned configuration, the natural frequency can be increased by reducing the mass of the first sliding part and the second sliding part, so that the leaf spring can be used normally even at a high rotation speed.

[0089] The flat spring according to a seventh aspect of the present invention is the flat spring of any one of the first to sixth aspects, wherein at least one of the first sliding portion and the second sliding portion is formed with projections and recesses.

[0090] According to the above configuration, projections and recesses are formed at the location where the first sliding portion and the second sliding portion contact each other, so that the area of ​​surface contact is reduced, making it possible to prevent the sliding portions from binding to each other.

[0091] A leaf spring according to an eighth aspect of the present invention is the leaf spring of any one of the first to seventh aspects, wherein the first ring and the second ring are made of metal.

[0092] According to the above-mentioned configuration, the first leaf spring and the second leaf spring can be electrically connected. Also, since the relationship between the displacement and the axial force is linear in the elastic region, it is easy to adjust the frictional force against the rotation.

[0093] A leaf spring according to a ninth aspect of the present invention may be configured as in any one of the first to eighth aspects above, wherein a first electrode having a divided pattern is formed on the first sliding portion, and a second electrode having a divided pattern is formed on the second sliding portion.

[0094] According to the above configuration, frictional electricity can be generated by the first electrode and the second electrode.

[0095] The leaf spring according to aspect 10 of the present invention comprises a first ring having a ring shape attached to a fixed part, and a second ring having a ring shape attached to a rotating part that rotates relative to the fixed part and shares a central axis with the first ring, wherein the first ring has a first sliding part and a first mounting part attached to the fixed part, and the second ring has a second sliding part that slides against the first sliding part and a second mounting part attached to the rotating part, and at least one of the first mounting part and the first sliding part or the second mounting part and the second sliding part are connected to each other by three or more flexible spring parts.

[0096] According to the above configuration, it is possible to achieve surface contact between the fixed portion and the rotating portion at the first sliding portion and the second sliding portion with a simple structure.

[0097] A bearing according to an eleventh aspect of the present invention comprises a first wheel, a second wheel sharing a central axis with the first wheel, a first ring fixed to the first wheel, and a second ring fixed to the second wheel and having an area in contact with the first ring, wherein a conductive DLC is formed in at least one of the band-shaped areas of the contact surfaces between the first ring and the second ring.

[0098] According to the above configuration, the conductive DLC is formed on the contact surface between the first sealing portion and the second sealing portion, so that the contact surface has high abrasion resistance. Furthermore, the conductivity is ensured, so that electrolytic corrosion can be prevented.

[0099] A twelfth aspect of the present invention relates to a bearing according to the eleventh aspect of the present invention, wherein the first ring has a first sliding portion and a first mounting portion that is mounted to the first wheel, and the second ring has The contact lens may have a second sliding portion that slides against the first sliding portion and a second mounting portion that is attached to the second wheel, and at least one of the first mounting portion and the first sliding portion, or the second mounting portion and the second sliding portion, are connected to each other by three or more flexible spring portions, and the first sliding portion or the second sliding portion may include the band-shaped region on which the conductive DLC is formed.

[0100] According to the above configuration, by providing the flexible spring portion, it is possible to realize surface contact between the first ring and the second ring.

[0101] A thirteenth aspect of the present invention relates to a bearing according to the eleventh or twelfth aspect above, and may be configured such that the first ring and the second ring are electrically conductive.

[0102] According to the above configuration, electrical continuity can be established between the first wheel and the second wheel via the first ring and the second ring.

[0103] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0104] 1, 2, 3, 100 Bearings 11 Outer wheel (first wheel) 12 Inner wheel (second wheel) 13 Rolling elements 14 Cage 15 Sealing part 16, 16a, 16b 1st Ring 17 Second Ring 18 Leaf spring 21 First mounting part 22 First flexible spring portion (flexible spring portion) 23, 23b first sliding portion 24, 34 void 25, 35 Conductive DLC film 26 holes 27 Uneven part 31 Second mounting part 32 Second flexible spring portion (flexible spring portion) 33 Second sliding part 50 Shaft 51 Housing 52 Clamp 60 1st electrode 63a, 63b Conductive patterns 64c, 63d Output terminals 70 2nd electrode 77 Insulation 78a Charged layer

Claims

1. A leaf spring provided in a bearing including a first wheel and a second wheel sharing a central axis with the first wheel, A first ring having a ring shape and provided to the first wheel; A ring-shaped second ring is provided to the second wheel and shares a central axis with the first ring, The first ring is A first sliding portion; A first attachment portion attached to the first wheel, The second ring is A second sliding portion that slides relative to the first sliding portion; A second mounting portion that is attached to the second wheel, At least one of the first mounting portion and the first sliding portion, or the second mounting portion and the second sliding portion, is connected to each other by three or more flexible spring portions.

2. The leaf spring of claim 1 , wherein the first ring and the second ring are electrically conductive.

3. 3. The leaf spring according to claim 1, wherein a conductive diamond-like carbon (DLC) is formed in a strip-shaped region of at least one of the first sliding portion and the second sliding portion at a contact surface between the first sliding portion and the second sliding portion.

4. The diameter of the first sliding portion is smaller than the diameter of the first mounting portion, The diameter of the second sliding portion is larger than the diameter of the second mounting portion, 3. The leaf spring according to claim 1, wherein a diameter of the first sliding portion is equal to or larger than a diameter of the second sliding portion.

5. The leaf spring according to claim 1 , wherein the flexible spring portion is formed in an arc shape.

6. The flat spring according to claim 1 , wherein at least one of the first sliding portion and the second sliding portion has a hole.

7. The flat spring according to claim 1 , wherein at least one of the first sliding portion and the second sliding portion has projections and recesses.

8. The leaf spring according to claim 1 or 2, wherein the first ring and the second ring are made of metal.

9. A first electrode having a divided pattern is formed on the first sliding portion, 3. The leaf spring according to claim 1, wherein the second sliding portion is provided with a second electrode having a divided pattern.

10. A first ring having a ring shape attached to the fixed portion; a ring-shaped second ring attached to a rotating part that rotates relative to the fixed part and shares a central axis with the first ring; The first ring is A first sliding portion; A first attachment portion attached to the fixed portion, The second ring is A second sliding portion that slides relative to the first sliding portion; a second attachment portion attached to the rotating portion, At least one of the first mounting portion and the first sliding portion, or the second mounting portion and the second sliding portion, is connected to each other by three or more flexible spring portions.

11. The first wheel, A second wheel sharing a central axis with the first wheel; a first ring fixed to the first wheel; a second ring fixed to the second wheel and having an area that contacts the first ring; A bearing, wherein a conductive DLC is formed in at least one band-shaped region of the contact surfaces between the first ring and the second ring.

12. The first ring is A first sliding portion; A first attachment portion attached to the first wheel, The second ring is A second sliding portion that slides relative to the first sliding portion; A second mounting portion that is attached to the second wheel, At least one of the first mounting portion and the first sliding portion or the second mounting portion and the second sliding portion is connected to each other by three or more flexible spring portions, The bearing according to claim 11 , wherein the first sliding portion or the second sliding portion includes the band-shaped region on which the conductive DLC is formed.

13. 13. A bearing according to claim 11 or 12, wherein the first ring and the second ring are electrically conductive.

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