Bearing with sensor
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- NTN CORP
- Filing Date
- 2022-09-14
- Publication Date
- 2026-06-26
Smart Images
Figure 0007880781000001 
Figure 0007880781000002 
Figure 0007880781000003
Abstract
Description
Technical Field
[0001] This invention relates to a bearing with a sensor, which includes a rolling bearing and a magnetic rotary sensor for detecting the relative rotational movement between the inner and outer rings of the rolling bearing.
Background Art
[0002] As a bearing with a sensor of this type, there is one in which a magnetic ring is connected to the outer peripheral portion of the inner ring of the rolling bearing, and a magnetic sensor unit is connected to the outer ring of the rolling bearing.
[0003] As the magnetic ring, one having magnetized magnetic rubber is used. The magnetic rubber has N poles and S poles alternately in the circumferential direction. In order to prevent deformation of the magnetic rubber, the magnetic rubber is fixed to a core metal. The magnetic ring is fixed to the inner ring by press-fitting the core metal into the outer peripheral portion of the inner ring. As the inner and outer rings rotate relative to each other, the magnetic ring and the magnetic sensor unit also rotate relative to each other, so the magnetic field detected by the magnetic sensor of the magnetic sensor unit changes. The magnetic sensor unit converts the change in the magnetic field into an electrical signal and outputs it (Patent Document 1).
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the case of a connecting structure in which the core of the magnetic ring is press-fitted onto the outer circumference of the inner ring, as in Patent Document 1, the magnetic ring is fixed by friction at the press-fitted fitting portion, so the width and radial interference fit of the fitting portion must be adequately secured. For this reason, if the thickness of the inner ring is small and the radial thickness between the inner and outer diameters of the rolling bearing (the bearing cross-sectional height from the inner diameter surface of the inner ring to the outer diameter surface of the outer ring) is small, there is a concern that the inner diameter surface of the inner ring will shrink due to the press-fitting of the core onto the outer circumference of the inner ring. Also, if the width of the inner ring is small, there is a concern that the width of the press-fit fitting portion on the outer circumference of the inner ring cannot be sufficiently secured. In the case of rolling bearings with these concerns, it is not possible to fix the magnetic ring to the outer circumference of the inner ring.
[0006] Furthermore, since the core of the magnetic ring is press-fitted onto the outer circumference of the inner ring, it is difficult to remove the magnetic ring from the inner ring without damaging it. For this reason, if the rolling bearing or inner ring needs to be replaced due to damage to the rolling bearing or inner ring, it is not possible to remove the magnetic ring from the inner ring and reuse it by attaching it to a new inner ring.
[0007] Therefore, the problem that this invention aims to solve is to prevent contraction of the inner diameter surface of the inner ring even when the magnetic ring of a magnetic rotation sensor is connected to the outer circumference of the inner ring of the inner ring of a rolling bearing, and to enable the connection of the outer circumference of the inner ring and the magnetic ring even when the width of the inner ring is small, while also improving the reusability of the magnetic ring when the inner ring is replaced. [Means for solving the problem]
[0008] To solve the above problems, this invention adopts a sensor bearing configuration 1 comprising a rolling bearing having an inner ring, an outer ring and a plurality of rolling elements, and a magnetic rotation sensor for detecting the relative rotational motion of the inner ring and the outer ring, wherein the inner ring has a raceway surface, a width surface located at one end of the width of the inner ring, and an outer circumference continuous from the width surface to the raceway surface, the magnetic rotation sensor has a magnetic ring connected to the outer circumference of the inner ring and a magnetic sensor unit connected to the outer ring, the magnetic ring having an annularly formed core and magnetic rubber fixed to the core, and further comprising an annularly formed hook member made of resin, an outer circumference groove extending in the circumferential direction formed on the outer circumference of the inner ring, the hook member having a projection that engages with the outer circumference groove of the inner ring, and the magnetic ring being held by the hook member.
[0009] According to the above configuration 1, the projection of the resin hook member can be pushed into the outer groove of the inner ring by utilizing the elastic deformation of the hook member, thereby locking it into the outer groove. Therefore, there is no need to secure a large radial interference fit and engagement width between the hook member and the outer circumference of the inner ring, as is the case with press-fit connection structures. Consequently, it is possible to fix the hook member to the outer circumference of the inner ring while avoiding contraction of the inner diameter surface of the inner ring, and it is also possible to fix the hook member to the outer circumference of the inner ring even when the width of the inner ring is small. Since the magnetic ring is held by the hook member, it is also possible to connect the magnetic ring to the outer circumference of the inner ring by the hook member and fix the position of the magnetic ring relative to the inner ring. Furthermore, since it is easy to extend the projection out of the outer groove of the inner ring by utilizing the elastic deformation of the hook member, it is less likely to damage the hook member and magnetic ring when removing them from the inner ring. Therefore, it is possible to improve the reusability of the magnetic ring when replacing the inner ring.
[0010] In the above configuration 1, a configuration 2 can be adopted in which the hook member has a groove extending in the circumferential direction, and the core metal is locked in the groove.
[0011] According to the above configuration 2, it is possible to push the core metal into the groove of the resin hook member and lock the core metal into the groove by utilizing the elastic deformation of the hook member. Therefore, it is not necessary to set a tight fit between the groove of the hook member and the core metal. Consequently, it is easy to remove the core metal from the groove by utilizing the elastic deformation of the hook member, making it less likely to damage the magnetic ring when removing the core metal from the groove. This improves the reusability of the magnetic ring after it has been removed from the hook member. Therefore, even if the hook member removed from the inner ring is damaged, deteriorated, etc. and unsuitable for reuse, it is possible to avoid replacing the magnetic ring.
[0012] In the above configuration 2, a configuration 3 can be adopted in which the hook member has an inner circumference including the groove, the core has a first plate surface and a second plate surface that face each other in the axial direction, the groove is located radially outward from the width surface of the inner ring, the first plate surface is in axial contact with the width surface of the inner ring, and the groove is engaged with the second plate surface.
[0013] According to the above configuration 3, since the groove is located radially outward on the inner circumference of the hook member compared to the width surface of the inner ring, the first plate surface can be in contact with the width surface of the inner ring to support the inner circumference of the mandrel in the axial direction, while the groove can be engaged with the second plate surface to support the outer circumference of the mandrel in the axial direction. Therefore, even if the engagement of the groove with the second plate surface is reduced, it is possible to maintain a constant position of the mandrel relative to the hook member and inner ring, and prevent the mandrel from tilting radially. Consequently, the radial depth of the groove can be made shallower to reduce the engagement of the groove with the second plate surface, thereby reducing the outer diameter of the hook member and making it easier to insert and remove the mandrel from the groove.
[0014] In the above configuration 3, configuration 4 can be adopted in which the magnetic rubber is adhered to the second plate surface.
[0015] According to the above configuration 4, the magnetic rubber can be positioned using the axial thickness of the part of the hook member that the groove portion of the core metal overlaps with the second plate surface, thereby reducing the amount of axial protrusion of the magnetic ring relative to the width surface of the inner ring.
[0016] In the above configuration 3 or 4, configuration 5 can be adopted in which the core is made of a metal plate oriented radially.
[0017] According to the above configuration 5, since the core is made of a metal plate oriented in the radial direction, it is possible to reduce the width and overall length of the core while keeping the processing cost low.
[0018] In any one of the above configurations 3 to 5, configuration 6 can be adopted in which the magnetic sensor unit has a magnetic sensor at a position facing the magnetic rubber in the axial direction.
[0019] According to the above configuration 6, the magnetic sensor and circuit board can be positioned while avoiding the space located radially outward from the magnetic rubber. Such an arrangement is suitable for positioning the magnetic rotation sensor so that it does not protrude radially from the rolling bearing, even when the radial thickness between the inner and outer diameters of the rolling bearing is small. [Effects of the Invention]
[0020] As described above, by adopting the above configuration 1, this invention makes it possible to avoid contraction of the inner diameter surface of the inner ring even when the magnetic ring of a magnetic rotary sensor is connected to the outer circumference of the inner ring of the rolling bearing, and also makes it possible to connect the outer circumference of the inner ring and the magnetic ring even when the width of the inner ring is small, while improving the reusability of the magnetic ring when the inner ring is replaced. [Brief explanation of the drawing]
[0021] [Figure 1] Figure 2 shows a longitudinal cross-sectional front view of a sensor-equipped bearing according to the first embodiment of this invention, cross-sectional view along line II. [Figure 2] Right side view of the sensor-equipped bearing according to the first embodiment. [Figure 3] Partial enlarged sectional view showing the sectional plane taken along line III-III in FIG. 2 [Figure 4] Diagram showing a jig set used in the process of attaching a magnetic ring to an inner ring according to the first embodiment [Figure 5] Diagram showing an example of a structure for applying preload to the bearing with sensor in FIG. 1 [Figure 6] Diagram showing another example of a structure for applying preload to the bearing with sensor in FIG. 1 [Figure 7] Vertical front view showing the bearing with sensor according to the second embodiment of this invention in a sectional plane similar to that in FIG. 1 [Figure 8] Partial enlarged sectional view showing the bearing with sensor in FIG. 7 in a sectional plane similar to that in FIG. 3 [Figure 9] Partial plan view showing a modified example of the outer protrusion of the sensor holder according to the second embodiment [Figure 10] Right side view showing an extract of the outer ring and the magnetic sensor unit of the bearing with sensor according to the second embodiment [Figure 11] Vertical front view showing the bearing with sensor according to the third embodiment of this invention in a sectional plane similar to that in FIG. 1 [Figure 12] Partial enlarged sectional view showing the bearing with sensor in FIG. 11 in a sectional plane similar to that in FIG. 3 [Figure 13] Right side view showing an extract of the outer ring and the magnetic sensor unit of the bearing with sensor according to the third embodiment
Mode for Carrying Out the Invention
[0022] The bearing with sensor according to the first embodiment as an example of this invention will be described based on FIGS. 1 to 6
[0023] The bearing with sensor shown in FIGS. 1 and 2 includes a rolling bearing 1 and a magnetic rotary sensor ⒉
[0024] The rolling bearing 1 has an inner ring 3, an outer ring 4, a plurality of rolling elements 5, a cage 6 for holding these rolling elements 5, and a seal 7 attached to the outer ring 4
[0025] The inner ring 3 has an outer circumference including the outer raceway surface 8 and an inner diameter surface 9 that defines the inner diameter of the rolling bearing 1, and consists of a single, seamless raceway ring. The outer ring 4 consists of a single raceway ring with a shape corresponding to the inner ring 3 and has an outer diameter surface 10 that defines the outer diameter of the rolling bearing 1. The inner ring 3 and the outer ring 4 are each formed from a metal such as bearing steel.
[0026] Hereinafter, the direction along the rotational axis of the rolling bearing 1 will be referred to as the "axial direction," the direction perpendicular to the rotational axis will be referred to as the "radial direction," and the direction around the circumference of the circle with the rotational axis as the centerline will be referred to as the "circumferential direction." In Figure 1, the axial direction corresponds to the left-right direction in the figure, and the radial direction corresponds to the up-down direction in the figure. The central axes of the inner ring 3 and the outer ring 4 coincide with the rotational axis of the rolling bearing 1.
[0027] The rolling elements 5 are interposed between the inner ring 3 and the outer ring 4. The cage 6 maintains the circumferential spacing between each rolling element 5. The inner ring 3 is used as a rotating wheel. The outer ring 4 is used as a stationary wheel. Due to the relative rotation of the inner ring 3 and the outer ring 4, the rolling elements 5 roll on the raceway surface 8 as the inner ring 3 rotates.
[0028] Although a ball bearing was used as an example of rolling bearing 1, it is also possible to change rolling bearing 1 to a roller bearing. Furthermore, although a non-separable bearing such as a deep groove ball bearing was used as an example of rolling bearing 1, it is also possible to change rolling bearing 1 to a separable bearing such as a tapered roller bearing.
[0029] Although the example shown illustrates a retainer 6 made from a press-formed thin metal sheet, the material and manufacturing method of the retainer 6 are not limited to this. It may be an iron plate retainer or a resin retainer formed by resin injection molding. As the resin, for example, a thermoplastic resin such as polyamide (PA) reinforced with glass fibers can be used. Furthermore, if the retainer 6 is made of resin, it may be a so-called crown-shaped retainer or a cage-shaped retainer.
[0030] The inner ring 3 has an outer circumference including a raceway surface 8 and an inner diameter surface 9 that defines the inner diameter of the rolling bearing 1. The inner ring 3 has a width surface 11 located at one end of the inner ring 3's width (right side in Figure 1), and an outer circumference 12 that extends from the raceway surface 8 to the width surface 11. The width of the inner ring 3 refers to its entire axial length. The width surface 11 is an annular surface aligned radially. An outer circumference groove 12a extending in the circumferential direction is formed on the outer circumference 12 of the inner ring 3. The outer circumference groove 12a has a groove width smaller than the width of the outer circumference 12 and extends continuously around the entire circumference. Of the outer circumference 12 of the inner ring 3, the shoulder portion 12b that extends between the outer circumference groove 12a and the width surface 11 consists of a cylindrical surface portion that is continuous with the outer circumference groove 12a and defines the outer diameter of the shoulder portion 12b, and a chamfer that extends from this portion to the width surface 11. A seal groove 13 extending around the entire circumference is formed on the outer circumference of the other end of the inner ring 3 (left side in Figure 1).
[0031] An inner circumferential groove 14 is formed at one end (the right end in Figure 1) of the inner circumference of the outer ring 4, and a seal groove 15 is formed at the other end (the left end in Figure 1). The inner circumferential groove 14 and the seal groove 15 are continuous around the entire circumference.
[0032] The inner ring 3 and outer ring 4 are standard sealed bearing components with a shape that is symmetrical with respect to a virtual plane along the radial direction, at positions that bisect the widths of the inner ring 3 and outer ring 4, respectively.
[0033] The seal 7 is attached to the other axial end (left side in Figure 1) of the annular bearing internal space formed between the inner ring 3 and the outer ring 4. It is locked into the seal groove 15 of the outer ring 4 (stationary ring). The seal 7 and the seal groove 13 of the inner ring 3 work together to prevent grease leakage from the bearing internal space and to prevent foreign matter from entering the bearing internal space. The seal 7 is made by vulcanizing and bonding oil-resistant rubber to a core metal made of press-formed thin sheet metal, and the oil-resistant rubber forms a lip that slides against the seal groove 13 and an outer circumference that is locked into the seal groove 15. Examples of oil-resistant rubber include nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluororubber (FKM), and acrylic rubber (ACM). The material and manufacturing method of the seal 7 are not particularly limited, and for example, it is possible to use a seal made by applying a rust-preventive coating such as tin plating or zinc plating to a press-formed thin metal sheet, or a seal made by press-forming a plated steel sheet that has been surface-treated in advance. Furthermore, while a contact seal was used as an example of seal 7, it is also possible to use a non-contact seal.
[0034] The magnetic rotation sensor 2 detects the relative rotational motion of the inner ring 3 and the outer ring 4. The magnetic rotation sensor 2 has a magnetic ring 16 connected to the outer circumference 12 of the inner ring 3 and a magnetic sensor unit 17 connected to the outer ring 4.
[0035] The magnetic ring 16 consists of a ring-shaped core metal 18 and magnetic rubber 19 fixed to the core metal 18. The magnetic ring 16 is connected to the outer circumference 12 of the inner ring 3 by a hook member 20.
[0036] The core metal 18 is made from a single, seamless metal sheet. The core metal 18 is press-formed from a single thin sheet. Examples of such metal sheets include mild steel sheets and stainless steel sheets. Examples of mild steel sheets include SPCC, SPCCT, SPCD, SPCE, and SPCEN as specified in the Japanese Industrial Standards (JIS). Examples of stainless steel sheets include SUS430, SUS201, SUS304, SUS316, SUS321, SUS403, and SUS410 as specified in the JIS. Furthermore, when machining the core metal 18, it is also possible to use carbon steel for machine structures such as S45C as specified in the JIS. In addition, using a magnetic material for the core metal 18 is advantageous for improving its magnetic properties.
[0037] The mandrel 18 has a concentric inner and outer circumference and is an annular shape along the radial direction. As shown in Figure 3, the mandrel 18 has a first plate surface 21 and a second plate surface 22 that face each other in the axial direction. The first plate surface 21 and the second plate surface 22 each consist of flat surfaces that are radially continuous and extend around the entire circumference. The mandrel 18 has an outer diameter surface 23 formed in a cylindrical shape. The periphery of one end side (right side in the figure) of the outer diameter surface 23 of the mandrel 18 forms a corner with the second plate surface 22. The outer diameter of the first plate surface 21 is set to be smaller than that of the outer diameter surface 23. Of the outer circumference of the mandrel 18, the portion between the periphery of the other end side (left side in the figure) of the outer diameter surface 23 and the first plate surface 21 is a tapered surface 24 that has an inclination in the direction of decreasing diameter from the outer diameter surface 23 towards the other end side (left side in the figure). The inner circumference of the mandrel 18 is cylindrical.
[0038] In order to reduce the overall length of the core metal 18 in the axial direction, a metal plate aligned radially was used as the core metal 18. However, this is not the only option. For example, a flange extending axially from the second plate surface 22 to one end can be press-formed by drawing or other processes for purposes such as positioning the magnetic rubber 19 or reinforcing the core metal.
[0039] The magnetic rubber 19 is formed in a ring shape from a rubber magnet material. The rubber magnet material is made by mixing magnetic powder with rubber. Examples of rubber include NBR, HNBR, FKM, and ACM. Examples of magnetic powder include ferrite powder, neodymium (Nd) powder, and samarium (Sm) powder.
[0040] The magnetic rubber 19 is fixed to the second plate surface 22 of the core metal 18 by adhesive. The magnetic rubber 19 has an inner and outer circumference concentric with the core metal 18 and is an annular shape along the radial direction. The outer diameter of the magnetic rubber 19 is set to be smaller than the outer diameter of the core metal 18 to avoid interference between the magnetic rubber 19 and the hook member 20.
[0041] The magnetic rubber 19 may be bonded to the core metal 18 along with vulcanization. When performing this vulcanization bonding, it is advisable to apply adhesive to the second plate surface 22 of the core metal 18 in advance.
[0042] The magnetic rubber 19 is multi-pole magnetized such that it has alternating north and south poles in the circumferential direction. The number of magnetization tracks is not particularly limited; at least one magnetization track is sufficient.
[0043] The magnetization process for the magnetic rubber 19 is not shown in the diagram, but for example, a magnetized ring is formed by fixing the magnetic rubber to the second plate surface of the core metal, and this magnetized ring is mounted on the rotating chuck (including the mounting jig) of the magnetization device and rotated in the circumferential direction at a constant rotational speed, thereby magnetizing the N pole and S pole alternately in the circumferential direction to form multiple poles. The magnetization device has a magnetization coil wound around a magnetization yoke and is positioned with a desired gap on the outer circumferential surface or width surface (flat surface) of the magnetized ring. Furthermore, by alternately switching the direction of the current flowing through the magnetization coil in synchronization with the rotation of the magnetized ring, the ring is magnetized to form multiple poles. The number of magnetized poles can be determined as appropriate.
[0044] Another magnetization method involves using a magnetization device in which a magnetization coil is wound around a magnetization yoke having a convex shape corresponding to the number of magnetic poles, which is positioned with a desired gap on the outer circumferential or width surface (flat surface) of the ring to be magnetized, which is fixed in a non-rotating state. In this case, the direction of the current flowing through the magnetization coil can be limited to one direction, and magnetization can be completed in a short time. This magnetization method is suitable for magnetizing Nd-based, Sm-based, and other types of materials.
[0045] The hook member 20 is formed in an annular shape from resin. The hook member 20 has an inner circumference and outer circumference concentric with the inner ring 3 and consists of a single, seamless resin member.
[0046] The inner circumference of the hook member 20 includes a projection 25 that engages with the outer circumferential groove 12a of the inner ring 3, and a groove 26 that extends in the circumferential direction.
[0047] The projection 25 consists of a portion of the hook member 20 that has a smaller diameter than the outer diameter of the shoulder portion 12b of the inner ring 3. The projection 25 is continuous around the entire circumference of the hook member 20. The other end of the projection 25 (left side in the figure) has a first inclined surface 25a that is inclined in a direction that increases in diameter from the inner diameter of the projection 25 (the inner circumference portion that defines the inner diameter of the projection 25) toward the other end (left side in the figure). The one end of the projection 25 (right side in the figure) has a second inclined surface 25b that is inclined in a direction that increases in diameter from the inner diameter of the projection 25 toward the one end (right side in the figure). The projection 25 engages axially with the outer groove 12a at the second inclined surface 25b. There is a space between the portion of the hook member 20 located on the inner diameter of the projection 25 and on the other end (left side in the figure) beyond that inner diameter, and the inner ring 3. This space and the first and second inclined surfaces 25a and 25b are designed to allow the hook member 20 to easily elastically deform when the projection 25 is inserted into and removed from the outer groove 12a over the shoulder portion 12b relative to the inner ring 3 from one end (the right side in the figure).
[0048] The groove 26 is continuous around the entire circumference and is positioned radially outward from the width surface of the inner ring. The mandrel 18 is locked into the groove 26. The groove 26 receives the outer diameter surface 23 of the mandrel 18 in the radial direction and is axially attached to the second plate surface 22. Of the groove 26, the bottom surface of the groove that receives the outer diameter surface 23 in the radial direction is cylindrical. Of the groove 26, the portion that is axially attached to the second plate surface 22 is aligned radially. The width of the groove 26 is wider than the width of the mandrel 18.
[0049] The hook member 20 is in radial contact with the outer diameter of the shoulder portion 12b of the inner ring 3 at the inner circumference portion connecting the groove portion 26 and the projection portion 25. The inner shoulder portion 27, which constitutes one end (the right end in the figure) of the inner circumference of the hook member 20, has a convex curved surface that protrudes most radially inward at the midpoint of the width of the inner shoulder portion 27.
[0050] The first plate surface 21 of the mandrel 18 is in axial contact with the width surface 11 of the inner ring 3, but not in axial contact with the hook member 20. There is a space between the first plate surface 21 and the hook member 20. This space, the curved shape of the inner shoulder portion 27 mentioned above, and the tapered surface 24 of the mandrel 18 are designed to easily elastically deform the hook member 20 and the mandrel 18 when inserting or removing the mandrel 18 into the groove portion 26 from one end (right side in the figure) over the inner shoulder portion 27 relative to the hook member 20.
[0051] The hook member 20 engages axially with the outer groove 12a of the inner ring 3 and the second plate surface 22 of the mandrel 18, thereby preventing the three components (inner ring 3, hook member 20, and mandrel 18) from separating axially from each other. The inner ring 3 and hook member 20 are concentrically positioned by the fit between the inner circumference of the hook member 20 and the outer groove 12a and shoulder portion 12b of the inner ring 3. The hook member 20 and mandrel 18 are concentrically positioned by the fit between the groove portion 26 of the hook member 20 and the outer diameter surface 23 of the mandrel 18. Relative rotation of these three components (20, 3, 19) is prevented by friction acting on the contact points between the outer circumference of the inner ring 3 and the inner circumference of the hook member 20, the contact points between the width surface 11 of the inner ring 3 and the first plate surface 21 of the mandrel 18, and the contact points between the second plate surface 22 and outer diameter surface 23 of the mandrel 18 and the hook member 20. Due to the axial displacement restriction, concentric arrangement, and rotation prevention of these three members (20, 3, 19), as shown in Figures 1 and 2, the hook member 20 is fixed to the outer circumference 12 of the inner ring 3, and the position of the magnetic ring 16 relative to the inner ring 3 is also fixed, thereby connecting the magnetic ring 16 to the outer circumference 12 of the inner ring 3. For this reason, the radial interference at the contact point between the inner circumference of the hook member 20 and the outer circumference 12 of the inner ring 3 is not set to a size that generates a force sufficient to contract the inner diameter surface 9 of the inner ring 3.
[0052] For example, an injection-molded thermoplastic resin can be used as the resin forming the hook member 20. For the portion of the core metal 18 that engages with the second plate surface 22 of the groove 26, a resin with elastic deformability, such as a polyacetal resin without fillers, can be used as appropriate, taking into consideration the ease of attaching and detaching the core metal 18 to the groove 26.
[0053] In the assembly process of connecting the magnetic ring 16 to the inner ring 3, the magnetic ring 16 can be easily connected to the inner ring 3 by using jigs Z1 to Z3 as shown in Figure 4.
[0054] The first step involves fitting the large-diameter shaft portion of the stepped shaft-shaped jig Z2 onto the inner diameter surface of jig Z1, which is set on the workbench. It is desirable that the gap between the fitting portions of jigs Z1 and Z2 be small.
[0055] Next, in the second step, the inner diameter surface 9 of the inner ring 3 of the rolling bearing 1 is fitted onto the large diameter shaft portion of the jig Z2 from the seal 7 side, and the inner ring 3 is brought into contact with the upper surface of the jig Z1. It is desirable that the gap between the large diameter shaft portion of the jig Z2 and the inner diameter surface 9 of the inner ring 3 be small.
[0056] Next, as a third step, the hook member 20 is placed with the projection 25 of the hook member 20 facing downwards, and the hook member 20 is passed through the small-diameter shaft portion of the jig Z2, so that the first inclined surface 25a of the projection 25 (see Figure 3) is in vertical contact with the chamfer of the shoulder portion 12b of the inner ring 3 (see Figure 3). The contact between the first inclined surface 25a of the projection 25 and the shoulder portion 12b of the inner ring 3 guides the hook member 20 to a position roughly concentric with the inner ring 3.
[0057] Next, as the fourth step, the projection 25 of the hook member 20 is pushed from above the inner ring 3 to the outer circumferential groove 12a, and locked into the outer circumferential groove 12a. In this fourth step, a jig Z3 having an inner diameter surface corresponding to the small diameter shaft portion of the jig Z2 shown in Figure 4 is used. By fitting the jig Z3 onto the small diameter shaft portion of the jig Z2 and pushing downward with the lower end of the jig Z3 directly above the projection 25 of the hook member 20 (the upper end portion facing the projection 25 in the vertical direction), a component force is generated at the contact point between the first inclined surface 25a of the hook member 20 and the shoulder portion 12b of the inner ring 3, which expands the diameter of the hook member 20. This makes it easy to cause the elastic deformation of the hook member 20 necessary for the hook member 20 to overcome the shoulder portion 12b downward. It is desirable that the gap between the small diameter shaft portion of the jig Z2 and the fitting portion of the jig Z3 be small.
[0058] Next, in the fifth step, with the magnetic rubber 19 of the magnetic ring 16 facing upwards, the core metal 18 is passed through the small diameter shaft portion of the jig Z2, and positioned so that the tapered surface 24 (see Figure 3) is in vertical contact with the inner shoulder portion 27 (see Figure 3) of the hook member 20. The contact between the tapered surface 24 of the core metal 18 and the inner shoulder portion 27 of the hook member 20 guides both members (18, 20) to be in a roughly concentric position.
[0059] Next, as the sixth step, the upper surface of the magnetic rubber 19 is pressed downwards from above, pushing the outer circumference of the core metal 18 into the groove 26 of the hook member 20, so that the core metal 18 is locked in the groove 26 as shown in Figure 4. This locking holds the core metal 18 in the groove 26 of the hook member 20. In this sixth step, by fitting the jig Z3 onto the small diameter shaft portion of the jig Z2 and pressing the upper surface of the magnetic rubber 19 downwards with the lower end of the jig Z3, a component force is generated at the contact point between the tapered surface 24 of the core metal 18 and the inner shoulder portion 27 of the hook member 20, which expands the diameter of the hook member 20. This makes it easy to cause the elastic deformation of the hook member 20 necessary for the outer circumference of the core metal 18 to move downwards over the inner diameter of the inner shoulder portion 27.
[0060] Furthermore, if the rolling bearing 1 is constructed by sealing grease in the internal space between the inner ring 3 and the outer ring 4, the grease sealing process may be carried out before fixing the hook member 20 to the inner ring 3.
[0061] The magnetic sensor unit 17 shown in Figure 1 has a sensor holder 28 connected to the outer ring 4 and a circuit board 29 attached to the sensor holder 28. A magnetic sensor 30, a connector 31, and the like are attached to the circuit board 29.
[0062] The sensor holder 28 is connected to the inner circumference of the outer ring 4 by being locked into the inner circumferential groove 14 of the outer ring 4. Therefore, the radial interference fit at the contact point between the sensor holder 28 and the inner circumferential groove 14 is not set to a size that would generate a force large enough to cause the outer diameter surface 10 of the outer ring 4 to expand.
[0063] The magnetic sensor 30 consists of an element that converts the magnetic field of the magnetic rubber 19 into an electrical signal. Of the magnetic sensor 30, the magnetosensitive part that converts the magnetic field into an analog electrical signal is positioned opposite the magnetic rubber 19 in the axial direction. The magnetic sensor 30 is surface-mounted on the other end (left side in the figure) of the circuit board 29. The sensor-side electrical circuit necessary for input and output between the magnetic sensor 30 and the outside is built on the circuit board 29. The connector 31 is the input / output terminal of the sensor-side electrical circuit and is connected to the external electrical circuit. The connector 31 is shaped to allow a cable (not shown) to be inserted and removed radially.
[0064] Furthermore, various electronic components (not shown) such as non-volatile memory and protection circuits are surface-mounted on the circuit board 29. These various electronic components are mounted for the purpose of attenuating or blocking harmful electrical noise from the outside. Examples of these various electronic components include common-mode filters, single-mode filters, resistors, ceramic capacitors, coils, varistors, inductors, ceramic filters, EMI filters, and ferrite beads.
[0065] The number of magnetic sensors 30 arranged using the sensor holder 28 may be one or more. If multiple magnetic sensors are used, they may be mounted on a single circuit board 29, or they may be mounted on two or more circuit boards. The sensor holder 28 may also be used to arrange sensors other than magnetic sensors 30, such as temperature sensors, vibration sensors, etc. These temperature sensors, etc., may be mounted on the circuit board 29, or they may be mounted on a separate circuit board from the circuit board 29 and then attached to the sensor holder.
[0066] It is desirable to use lead-free solder for soldering the magnetic sensor 30 and other components. It is desirable to surface mount the magnetic sensor 30, ceramic capacitor, and non-volatile memory on the same side of the circuit board 29, and surface mount other electronic components, such as protection circuit components and connector 31, on the opposite side. In particular, by mounting the ceramic capacitor close to the power supply terminal and GND terminal of the magnetic sensor 30, external electrical noise (voltage change) components superimposed on the power supply can be effectively grounded.
[0067] Furthermore, it is desirable to use glass-filled epoxy resin for the circuit board 29, and selecting a material with a compressive strength of 340-500 MPa and a bending strength of 390-550 MPa will increase rigidity and improve rotation detection accuracy. In addition, by making the circuit board 29 a multilayer board, the dimensions of the circuit board 29 can be made smaller.
[0068] The circuit board 29, magnetic sensor 30, and various electronic components may be covered with a sheet of thermosetting resin or coated with a resin-based moisture-proof film to prevent migration.
[0069] When employing a magnetic sensor 30 that can be programmed with data, a through-hole (not shown) is provided in a portion of the connector 31 mounting surface of the circuit board 29, allowing a connection terminal such as a pin header (not shown) to be inserted during the programming process to write the data, and then the connection terminal can be removed afterward.
[0070] As shown in Figure 1, the sensor holder 28 has a sensor window 32 formed in a position facing the magnetic rubber 19 of the magnetic ring 16 in the axial direction. The sensor window 32 is a space for positioning the magnetic sensor 30 in a position facing the magnetic pole surface of the magnetic rubber 19 in the axial direction.
[0071] As shown in Figures 2 and 3, the sleeve-integrated nut 33 is inserted into the through-hole of the sensor holder 28 from the other end (left side in Figure 3), the through-hole of the circuit board 29 and the round hole of the washer 35 are positioned on one end of the sensor holder 28 (right side in Figure 3), and the screw member 34 is screwed onto the sleeve-integrated nut 33 from one end (right side in Figure 3) relative to the washer 35, thereby fastening the circuit board 29 and the sensor holder 28. Two such fastening points are provided, separated on both sides in the circumferential direction of the circuit board 29.
[0072] The sensor holder 28 consists of an outer ring member 36 formed in a cylindrical shape from a metal plate and a rubber part 38 fixed to the outer flange portion 37 of the outer ring member 36. The outer ring member 36 has an inner flange portion 36a that protrudes radially inward at one end of the outer ring member 36 (the right end in Figure 3). The inner flange portion 36a is formed around the entire circumference. The sensor window 32 penetrates the inner flange portion 36a in the axial direction. Of the inner flange portion 36a, the range of the circumferential angle θ including the sensor window 32 protrudes radially inward more than the circumferential portion other than the angle θ. The circuit board 29 is fastened to this range of angle θ. The angle θ is, for example, 65°. The outer flange portion 37 protrudes radially outward at the other end of the outer ring member 36 (the left end in Figure 3). Such an outer ring member 36 can be manufactured by press forming a thin sheet of mild steel, stainless steel, etc. For example, a disc-shaped blank plate can be roughly drawn into a cup shape to form a cup body with an outer flange 37, and the bottom of the cup can be punched out to form an inner flange. Note that the outer flange 37 does not need to be continuous around the entire circumference, and although not shown in the illustration, it is also possible to provide the outer flanges intermittently in the circumferential direction and create slits (spaces) between adjacent outer flanges in the circumferential direction.
[0073] The rubber portion 38 is bonded to the sensor holder 28 so as to cover the outer circumference and both ends of the outer flange portion 37. The rubber portion 38 may be made of oil-resistant rubber such as NBR, HNBR, FKM, or ACM, which may be vulcanized and bonded to the outer ring member 36.
[0074] The assembly process for connecting the sensor holder 28 to the outer ring 4 is performed after attaching the magnetic ring 16 to the inner ring 3. This assembly process is also performed with the circuit board 29 attached to the inner flange portion 36a of the sensor holder 28. In this assembly process, the sensor holder 28 is positioned on one end (right side in Figure 3) of the outer ring 4, and the elasticity of the rubber portion 38 is used to compress and deform the rubber portion 38 into the inner circumferential groove 14, and then it is pushed in. After this pushing, the restoring force of the rubber portion 38 causes the rubber portion 38 to fit into the inner circumferential groove 14, thereby locking the sensor holder 28 into the inner circumferential groove 14. This locking restricts the axial, radial, and circumferential displacement of the sensor holder 28 relative to the outer ring 4, so that the sensor holder 28 is fixed to the inner circumference of the outer ring 4.
[0075] Even if there is no problem with the magnetic rotation sensor 2 of this sensor-equipped bearing shown in Figure 1, there may be cases where the inner ring 3 must be replaced with a new one. In the case of the sensor-equipped bearing shown in Figure 1, since the rolling bearing 1 is a non-separable bearing, if at least one of the inner ring 3, outer ring 4, rolling elements 5, and cage 6 is damaged and becomes unusable, the entire rolling bearing 1, including the inner ring 3, will have to be replaced with a new one. In such cases, the following measures can be taken to allow the reuse of the magnetic rotation sensor 2.
[0076] To reuse the magnetic sensor unit 17, first remove it from the outer ring 4. For example, by placing a suitable bearing puller (not shown) on the inner flange portion 36a of the sensor holder 28 (see Figures 1 and 3) and pulling the sensor holder 28 evenly in the circumferential direction toward one end (right side in the same figure) using the bearing puller, the rubber portion 38 of the sensor holder 28 is elastically compressed, allowing it to be easily removed from the inner circumferential groove 14 of the outer ring 4. If the removed sensor holder 28 is undamaged, the removed magnetic sensor unit 17 can be connected to the outer ring 4 of a new rolling bearing 1 and reused.
[0077] Even if the sensor holder 28 is damaged to the point of being unsuitable for reuse when it is removed from the outer ring 4, the circuit unit, including the circuit board 29 and magnetic sensor 30, can be removed from the damaged sensor holder 28 by unscrewing all the screw members 34 fastening the damaged sensor holder 28 to the circuit board 29. The removed circuit unit can then be attached to a new sensor holder 28 and connected to the outer ring 4 of the new rolling bearing 1, allowing the circuit unit to be reused.
[0078] Furthermore, when reusing the magnetic sensor unit 17, first, the hook member 20 that holds the magnetic ring 16 is removed from the inner ring 3. This removal can be done, for example, by placing a suitable bearing puller (not shown) on the other end of the hook member 20 (the left end in Figures 1 and 3) and pulling the hook member 20 evenly in the circumferential direction toward one end (the right side in the same figures) with the bearing puller. This generates a component force that expands the diameter of the hook member 20 at the contact point between the second inclined surface 25b of the projection 25 of the hook member 20 and the outer circumferential groove 12a of the inner ring 3. This allows the resin hook member 20 to be easily elastically deformed, and the projection 25 to be easily removed from the outer circumferential groove 12a. If the removed hook member 20 is undamaged, the removed hook member 20 and the magnetic ring 16 held therein can be connected to the inner ring 3 of a new rolling bearing 1 and reused.
[0079] Even if the hook member 20 is damaged to the point of being unsuitable for reuse when it is removed from the inner ring 3, the magnetic ring 16 can be removed from the damaged hook member 20 by extending the core metal 18 from the groove 26 of the damaged hook member 20, the removed magnetic ring 16 can be attached to a new hook member 20, and this can be connected to the inner ring 3 of a new rolling bearing 1, thereby allowing the magnetic ring 16 to be reused. Here, once the hook member 20 is removed from the inner ring 3, there is no longer any contact between the width surface 11 of the inner ring 3 and the first plate surface 21 of the core metal 18. This allows the core metal 18, which is held in the groove 26 of the removed hook member 20, to be moved to the other end of the groove 26 (the left side in the figure), creating a gap between the second plate surface 22 of the core metal 18 and the groove 26. Furthermore, the groove 26 of the resin hook member 20 is shallow in the radial direction, and there is little engagement with the second plate surface 22 of the core metal 18 (because the difference in diameter between the inner diameter of the inner shoulder 27 and the outer diameter surface 23 of the core metal 18 is small). By inserting a removal tool such as a flathead screwdriver into the gap between the inner shoulder 27 and the outer circumference of the magnetic rubber 19, and pushing the inner shoulder 27 radially outward with the removal tool, the hook member 20 is elastically deformed so that the inner shoulder 27 overcomes the outer diameter surface 23 of the core metal 18 to the other end (left side in the figure), and the core metal 18 can be easily removed from the groove 26.
[0080] An example of the use of this sensor-equipped bearing is shown in Figure 5. Figure 5 shows a cross-sectional view of a typical structure in, for example, an electric motor (induction motor / synchronous motor, DC motor, etc.).
[0081] The inner diameter surface 9 of the inner ring 3 is fitted to the small diameter shaft portion of the stepped shaft-shaped rotating shaft 100. The width surface of the other end (left side in the figure) of the inner ring 3 abuts against the shaft shoulder 101. The outer diameter surface 10 of the outer ring 4 is fitted to the housing 102. A nut 103 is screwed onto one end (right end in the figure) of the rotating shaft 100. An annular spacer 104 is sandwiched axially between the nut 103 and the inner ring 3. The inner ring 3 is mounted on the rotating shaft 100 by screwing on the nut 103. The width surface of the other end (left side in the figure) of the outer ring 4 abuts against the spacer 105. A cover 106 is fastened axially to one end (right end in the figure) of the housing 102. The cover 106 pushes the outer ring 4 toward the other end (left side in the figure), thereby fixing the outer ring 4 in the axial direction. At this time, force is transmitted from the width surface of one end of the outer ring 4 (right side in the figure) to the width surface of the other end of the inner ring 3 (left side in the figure) via the rolling elements 5, and preload is applied to the rolling bearing 1. As a result, the gaps between the inner ring 3, rolling elements 5, and outer ring 4 of the rolling bearing 1 are appropriately maintained. In this case, the width dimension of the spacer 105 is appropriately controlled. This increases the rigidity of the rolling bearing 1, improving high-speed rotation, rotational accuracy, positioning accuracy, etc.
[0082] When the rotating shaft 100 rotates relative to the housing 102, the inner ring 3, which rotates integrally with the rotating shaft 100, rotates relative to the outer ring 4. At this time, the magnetic rotation sensor 2 (see Figures 1 and 5) detects a change in the magnetic field of the magnetic rubber 19 of the magnetic ring 16 as it rotates relative to the magnetic sensor 30 in response to the relative rotation of the inner ring 3 and the outer ring 4. The magnetic sensor 30 converts this change in the magnetic field into an electrical signal and outputs it from the connector 31 as a signal indicating the rotation angle of the inner ring 3 (rotating shaft 100), etc.
[0083] Although Figure 5 illustrates a fixed-position preload method, as shown in Figure 6, it is also possible to adopt a constant-pressure preload method in which a spring 110 such as a wave washer is placed between the cover 106 and the inner ring 3, and the spring 110 is compressed by fastening the cover 106 to the housing 102, thereby applying preload to the rolling bearing 1.
[0084] The sensor-equipped bearing shown in Figures 1-3 is as described above, and comprises a rolling bearing 1 having an inner ring 3, an outer ring 4, and a plurality of rolling elements 5, and a magnetic rotation sensor 2 that detects the relative rotational motion of the inner ring 3 and the outer ring 4. The inner ring 3 has a raceway surface 8, a width surface 11 located at one end of the width of the inner ring 3, and an outer circumference 12 that extends from the width surface 11 to the raceway surface 8. The magnetic rotation sensor 2 has a magnetic ring 16 connected to the outer circumference 12 of the inner ring 3 and a magnetic sensor unit 17 connected to the outer ring 4. The magnetic ring 16 has a mandrel 18 formed in an annular shape and magnetic rubber 19 fixed to the mandrel 18.
[0085] In particular, this sensor-equipped bearing further includes a hook member 20 formed in an annular shape from resin, and an outer groove 12a extending in the circumferential direction is formed on the outer circumference 12 of the inner ring 3. The hook member 20 has a projection 25 that is locked into the outer groove 12a of the inner ring 3, and the magnetic ring 16 is held by the hook member 20. This makes it possible to push the projection 25 of the resin hook member 20 into the outer groove 12a of the inner ring 3 by utilizing the elastic deformation of the hook member 20, thereby locking it into the outer groove 12a. For this reason, it is not necessary to secure a large radial interference fit and engagement width between the hook member 20 and the outer circumference 12 of the inner ring 3, as is the case with press-fitting connecting structures. Therefore, it is possible to fix the hook member 20 to the outer circumference 12 of the inner ring 3 while avoiding contraction of the inner diameter surface 9 of the inner ring 3, and it is also possible to fix the hook member 20 to the outer circumference 12 of the inner ring 3 even when the width of the inner ring 3 is small. Since the magnetic ring 16 is held by the hook member 20, it is possible to connect the magnetic ring 16 to the outer circumference 12 of the inner ring 3 using the hook member 20, thereby fixing the position of the magnetic ring 16 relative to the inner ring 3. Furthermore, since it is easy to extend the protrusion 25 from the outer circumference groove 12a of the inner ring 3 by utilizing the elastic deformation of the hook member 20, the hook member 20 and the magnetic ring 16 are less likely to be damaged when removed from the inner ring 3. Therefore, it is possible to improve the reusability of the magnetic ring 16 when replacing the inner ring 3 (rolling bearing 1).
[0086] Thus, the purpose of this sensor-equipped bearing is to prevent contraction of the inner diameter surface 9 of the inner ring 3 even when the magnetic ring 16 of the magnetic rotary sensor 2 is connected to the outer circumference 12 of the inner ring 3 of the rolling bearing 1, and to enable connection of the outer circumference 12 of the inner ring 3 and the magnetic ring 16 even when the width of the inner ring 3 is small, while also improving the reusability of the magnetic ring 16 when the inner ring 3 is replaced.
[0087] Furthermore, in this sensor-equipped bearing, the hook member 20 has a groove 26 extending in the circumferential direction, and the core metal 18 is locked in the groove 26. This allows the core metal 18 to be pushed into the groove 26 of the resin hook member 20, and the elastic deformation of the hook member 20 is used to lock the core metal 18 into the groove 26. Therefore, there is no need to set a tight tension between the groove 26 of the hook member 20 and the core metal 18. Consequently, it is easy to remove the core metal 18 from the groove 26 using the elastic deformation of the hook member 20, making it less likely to damage the magnetic ring 16 when removing the core metal 18 from the groove 26. As a result, this sensor-equipped bearing can improve the reusability of the magnetic ring 16 after it has been removed from the hook member 20. Therefore, even if the hook member 20 removed from the inner ring 3 is damaged, deteriorated, or otherwise unsuitable for reuse, the replacement of the magnetic ring 16 can be avoided.
[0088] Furthermore, in this sensor-equipped bearing, the hook member 20 has an inner circumference including a groove 26, and the mandrel 18 has a first plate surface 21 and a second plate surface 22 that face each other in the axial direction. The groove 26 is located radially outward from the width surface 11 of the inner ring 3, the first plate surface 21 is in axial contact with the width surface 11 of the inner ring 3, and the groove 26 engages with the second plate surface 22. As a result, the inner circumference of the mandrel 18 can be supported in the axial direction by contacting the width surface 11 of the inner ring 3 with the first plate surface 21, while the outer circumference of the mandrel 18 can be supported in the axial direction by engaging the groove 26 with the second plate surface 22. Therefore, even if the engagement of the groove 26 with respect to the second plate surface 22 is reduced, it is possible to maintain a constant position of the mandrel 18 relative to the hook member 20 and the inner ring 3, and to prevent the mandrel 18 from tilting in the radial direction. Therefore, this sensor-equipped bearing reduces the radial depth of the groove 26, thereby reducing the engagement of the groove 26 with the second plate surface 22, and consequently reducing the outer diameter of the hook member 20, while also making it easier to insert and remove the core metal 18 from the groove 26.
[0089] Furthermore, in this sensor-equipped bearing, since the magnetic rubber 19 is bonded to the second plate surface 22, the magnetic rubber 19 can be positioned using the axial thickness (the width of the inner shoulder portion 27) of the core metal 18 where the groove portion 26 of the hook member 20 engages with the second plate surface 22, thereby reducing the amount of axial protrusion of the magnetic ring 16 relative to the width surface 11 of the inner ring 3.
[0090] Furthermore, this sensor-equipped bearing has a core metal 18 made of a metal plate oriented radially, Since the core metal 18 is made of a metal plate oriented in the radial direction, there is no need for flange forming or drawing during the manufacturing of the core metal 18. This allows for a core metal 18 with low processing costs while keeping the width and overall length in the radial direction of the core metal 18 to a minimum.
[0091] Furthermore, in this sensor-equipped bearing, the magnetic sensor unit 17 has the magnetic sensor 30 positioned axially opposite to the magnetic rubber 19, allowing the magnetic sensor 30 and the circuit board 29 to be positioned while avoiding the space located radially outward from the magnetic rubber 19. Such an arrangement is suitable for positioning the magnetic rotation sensor 2 so that it does not protrude radially from the rolling bearing 1, even when the radial thickness between the inner diameter (inner diameter surface 9 of the inner ring 3) and the outer diameter (outer diameter surface 10 of the outer ring 4) of the rolling bearing 1 is small.
[0092] Furthermore, in this sensor-equipped bearing, the outer ring 4 has an inner circumferential groove 14, and the magnetic sensor unit 17 is locked in the inner circumferential groove 14. This improves the reusability of the magnetic sensor unit 17 when the outer ring 4 is replaced, and even when the magnetic sensor unit 17 is connected to the inner circumference of the outer ring 4, expansion of the outer diameter surface 10 of the outer ring 4 can be avoided. Moreover, the magnetic sensor unit 17 can be connected to the inner circumference of the outer ring 4 even when the width dimension of the outer ring 4 is small.
[0093] As described above, this sensor-equipped bearing is economical because, when replacing the rolling bearing 1, the magnetic ring 16, hook member 20, and magnetic sensor unit 17 can be removed from the rolling bearing 1 and reused.
[0094] Furthermore, since this sensor-equipped bearing has a structure in which the hook member 20 is locked into the outer circumferential groove 12a of the inner ring 3 and the sensor holder 28 is locked into the inner circumferential groove 14 of the outer ring 4, it is possible to use a standard sealed bearing as the rolling bearing 1, and there is no need to increase the width dimensions of the inner ring 3 and outer ring 4, and no extra costs are incurred in the bearing manufacturing process, which is advantageous in reducing overall costs.
[0095] Furthermore, in this sensor-equipped bearing, the hook member 20 that holds the magnetic ring 16 is locked into the outer circumferential groove 12a of the inner ring 3, and the sensor holder 28 is locked into the inner circumferential groove 14 of the outer ring 4. Therefore, even if the radial thickness between the inner diameter (inner diameter surface 9 of the inner ring 3) and the outer diameter (outer diameter surface 10 of the outer ring 4) of the rolling bearing 1 is small, the inner diameter surface 9 of the inner ring 3 does not contract, and the outer diameter surface 10 of the outer ring 4 does not expand even when the sensor holder 28 is connected to the inner circumference of the outer ring 4.
[0096] Furthermore, in this sensor-equipped bearing, even when the magnetic ring 16 is connected to the outer circumference 12 of the inner ring 3 by the hook member 20, the inner diameter surface 9 of the inner ring 3 does not contract, and even when the sensor holder 28 is connected to the inner circumference of the outer ring 4, the outer diameter surface 10 of the outer ring 4 does not expand. Therefore, in terms of the dimensions of the rolling bearing 1, it is possible to treat it as a rolling bearing of standard dimensions.
[0097] Furthermore, this invention is not limited to rolling bearings with a small radial thickness between the inner and outer diameters, but is applicable to all rolling bearings.
[0098] Furthermore, the locking structure of the sensor holder against the inner circumferential groove of the outer ring is not limited to one that utilizes the elastic deformation of the rubber part, and can be changed to other locking structures. A second embodiment as an example is shown in Figures 7 to 10. In the following, only the differences from the first embodiment will be described.
[0099] The magnetic sensor unit 40 according to the second embodiment has a sensor holder 41 made of resin. The sensor holder 41 consists of a single, seamless cylindrical member. As shown in Figures 8 and 9, the outer circumference of the sensor holder 41 includes a first projection 42 located at the other end of the sensor holder 41 (the left end in Figure 8) and a second projection 43 located at one end relative to the projection 42 (the right side in Figure 8).
[0100] The first protrusion 42 is locked into the inner circumferential groove 14 of the outer ring 4. The first protrusion 42 is provided intermittently in the circumferential direction to facilitate pushing into the inner circumferential groove 14. There are slits (spaces) between each adjacent first protrusion 42 in the circumferential direction. It is also possible to have the first protrusion 42 continuous around the entire circumference.
[0101] The second protrusion 43 abuts axially against the width surface of one end of the outer ring 4 (right side in Figure 8) to restrict the axial displacement of the sensor holder 41 toward one end (right side in Figure 8). The second protrusion 43 is continuous around the entire circumference.
[0102] As shown in Figures 8 and 10, the sensor holder 41 has an inner flange portion 44 with the same shape as the first embodiment, but as shown in Figure 8, the thickness of the inner flange portion 44 and other required parts is increased compared to the first embodiment. Therefore, even though it is made of resin, it has sufficient strength and rigidity for fastening and supporting the circuit board 29. The area around the nut 33 is countersunk. Note that the inner ring, hook member and magnetic ring are not shown in Figure 10.
[0103] The sensor holder 41 can be formed seamlessly as a whole by, for example, injection molding a thermoplastic resin. The resin used to form the sensor holder 41 can be appropriately selected depending on the operating environment of the sensor holder 41. For example, if a thermoplastic resin made of polyphenylene sulfide (PPS) filled with glass fibers, calcium carbonate, etc. is used, the dimensional stability of the sensor holder 41 with respect to ambient temperature will be improved. Furthermore, when used in environments with generally little temperature fluctuation, such as room temperature, materials such as polybutylene terephthalate (PBT) or polyacetal (POM) can be used.
[0104] In the first and second embodiments, a sensor holder continuous around the entire circumference was illustrated, but it is also possible to make the sensor holder an end-ring shape with a complete discontinuity in a circumferential region. A third embodiment, as an example of this, is shown in Figures 11 to 13. The third embodiment is a further modification of the sensor holder from the second embodiment, so only the changes from the second embodiment will be described here. Note that the inner ring, hook member, and magnetic ring are not shown in Figure 13.
[0105] The sensor holder according to the third embodiment comprises a holder body 50 that is completely discontinuous in a part of the circumferential direction and has a first circumferential end 51 and a second circumferential end 52 that face each other in the circumferential direction, and a spring member 53 arranged to bias the holder body 50 in the radial expansion direction.
[0106] The holder body 50 consists of a single, seamless resin section and includes a first protrusion 42 and a second protrusion 43. There is a space between the first circumferential end 51 and the second circumferential end 52.
[0107] The spring member 53 is an annular shape with an end that is completely discontinuous in a portion of its circumferential direction. The spring member 53 is made of a thin metal plate formed into a C shape that is completely discontinuous in a portion of its circumferential direction. The spring member 53 is mounted in a groove that extends circumferentially with axial depth from the end face of the other end (left side in Figures 11 and 12) to the one end (right side in Figures 11 and 12) of the holder body 50. The spring member 53 extends for approximately the entire circumferential length of the holder body 50.
[0108] The first projection 42 is fitted into the inner groove 14 of the outer ring 4 while elastically deforming the holder body 50 (including the spring member 53) in a direction that brings the first circumferential end 51 and the second circumferential end 52 of the holder body 50, to which the spring member 53 is attached, closer together. After this fitting, when the holder body 50 and the spring member 53 are elastically restored, the first projection 42 becomes locked in the inner groove 14, and this state is maintained thereafter by the elastic restoring force of the spring member 53. As a result, the holder body 50 is fixed to the outer ring 4.
[0109] Furthermore, the spring member 53 is not limited to a C-shaped leaf spring; a C-shaped wire spring can also be used. Additionally, the spring member can be interposed between the first and second circumferential ends of the holder body, and the elastic restoring force of the spring member can push both circumferential ends of the holder body away from each other in the circumferential direction, thereby biasing the holder body in a direction that expands its diameter.
[0110] The sensor-equipped bearings according to each of the above embodiments can be applied to, for example, the following functions a to c, applications a to f, etc.
[0111] Function a: The absolute angle of rotation is detected by the absolute output of the magnetic rotation sensor. Function b: The speed and direction of rotation are detected by the incremental output of the magnetic rotation sensor. Function c: Detects the rotational position of a rotating body such as a motor rotor.
[0112] Application a: Detection of rotational angles of joints in various robots such as household robots, industrial robots, and AI robots. Application b: Detection of rotation angle of the swivel mechanism of various robots. Application c: Rotation detection of various motors such as AC servo motors, DC servo motors, and hydraulic motors. Application d: Rotation detection of various transmissions such as speed reducers and speed increasers. Application e: Position detection of various polygon mirrors that reflect laser light in laser printers, medical imaging equipment, etc. Application f: Rotation detection and position detection for various machines such as industrial machinery, construction machinery, and spindles.
[0113] Furthermore, sensor-equipped bearings with thin-walled or narrow-width rolling bearings are used, for example, in various robots, small motors, and the like.
[0114] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications in the sense and scope equivalent to the claims are intended to be included. [Explanation of Symbols]
[0115] 1 Rolling bearing 2. Magnetic rotation sensor 3. Inner Ring 4 Outer ring 5 Rolling element 8 Raceway surface 9 Inner diameter surface 10 Outer diameter surface 11 Width side 12 Outer periphery 12a Outer groove 16 Magnetic Rings 17,40 Magnetic Sensor Unit 18 Mandrel 19 Magnetic rubber 20 Hook members 21 First board surface 22 Second board surface 25 Protrusion 26 Groove 30 Magnetic Sensors
Claims
1. A rolling bearing comprising an inner ring, an outer ring, and a plurality of rolling elements, and a magnetic rotation sensor for detecting the relative rotational motion of the inner ring and the outer ring, The inner ring has a raceway surface, a width surface located at one end of the width of the inner ring, and an outer circumference that is continuous from the width surface to the raceway surface. The magnetic rotation sensor comprises a magnetic ring connected to the outer circumference of the inner ring and a magnetic sensor unit connected to the outer ring. In a sensor-equipped bearing having a magnetic ring formed in an annular shape and magnetic rubber fixed to the core, It further comprises a hook member formed in an annular shape from resin, An outer circumferential groove is formed on the outer circumference of the inner ring, The hook member has a projection that is engaged with the outer groove of the inner ring, The core metal is held by the hook member, The hook member has an inner circumference including a groove that extends in the circumferential direction, The core metal is locked in the groove, The core metal has a first plate surface and a second plate surface that face each other in the axial direction, The groove is located radially outward from the width surface of the inner ring. The first plate surface is in contact with the width surface of the inner ring, A sensor-equipped bearing characterized in that the groove portion is engaged with the second plate surface.
2. The sensor bearing according to claim 1, wherein the magnetic rubber is fixed to the second plate surface.
3. The sensor bearing according to claim 1 or 2, wherein the core is made of a metal plate oriented radially.
4. The sensor bearing according to claim 1 or 2, wherein the magnetic sensor unit has a magnetic sensor at a position facing the magnetic rubber in the axial direction.