Rotor, motor
The rotor design with a projection and storage space for wear particles ensures stable mounting of rolling bearings, addressing wear particle issues and improving motor performance by maintaining uniform load application and preventing particle entry.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2022-03-02
- Publication Date
- 2026-06-19
AI Technical Summary
Conventional methods for press-fitting rolling bearings into housings and shafts result in wear particle generation, which can lead to damage, abnormal noise, and improper alignment due to non-uniform force application, causing wear particles to enter the bearing and affect its operation.
A rotor design with a cylindrical inner ring featuring a projection that directs the press-fitting load to a specific area, creating a storage space for wear particles, ensuring uniform load application and preventing particle entry into the bearing.
The design stabilizes the mounting process by preventing wear particle interference, reducing damage and noise, and maintaining proper alignment of rolling bearings, thus enhancing the operational reliability of the rotor and motor.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a rotor and a motor.
Background Art
[0002] Conventionally, when inserting a rolling bearing into a shaft or a housing, a method of pressing using a press-fit jig or the like is known. The press-fit surface of the press-fit jig faces the press-fit surface of the rolling bearing and can press while applying an even load perpendicular to the press-fit surface. If there is a deviation in the load, the rolling bearing will be inserted in a tilted state, resulting in damage such as flaking and deterioration of the roundness of the rolling elements, which causes abnormal noise in the rolling bearing.
[0003] Therefore, a method for stably press-fitting a rolling bearing on a surface orthogonal to the press-fitting direction has been studied. As an example, a bearing mounting structure provided with a positioning portion capable of gently inserting a rolling bearing is known (see, for example, Patent Document 1). The structure will be described below with reference to FIG. 9.
[0004] FIG. 9 is a cross-sectional view of the rolling bearing mounting structure in Patent Document 1. In a bearing housing 112 provided in a frame 103, a positioning portion 114 is formed by making the vicinity of its open end 113 slightly larger than the outer diameter of the rolling bearing 102. Further, below the positioning portion 114 provided near the open end 113 of the inner peripheral surface of the bearing housing 112, the diameter of the inner peripheral surface of the bearing housing 112 is formed slightly smaller than the outer diameter of the rolling bearing 102 so that the rolling bearing 102 can be press-fitted and fixed.
[0005] With the above configuration, when the rolling bearing 102 is gently inserted into the open end 113 of the bearing housing 112, it is said that the rolling bearing 102 is held by the positioning portion 114 and can be correctly positioned in the press-fitting direction of the bearing housing 112.
Prior Art Documents
Patent Documents
[0006] [Patent Document 1] Japanese Utility Model Publication No. 62-166324 [Overview of the project] [Problems that the invention aims to solve]
[0007] Conventional configurations like this have the following problems.
[0008] In conventional configurations, friction between the rolling bearing and the housing generates wear particles when the rolling bearing is pressed into the housing. Because there is no gap between the rolling bearing and the housing, there is a risk that foreign matter such as the generated wear particles may enter the inside of the rolling bearing. Furthermore, if wear particles adhere to the press-fitting jig used to press-fit the rolling bearing, the press-fitting surface of the jig may deform, making it impossible to apply uniform force to the rolling bearing during press-fitting. As a result, the rolling bearing cannot be pressed in perpendicular to the press-fitting surface, leading to problems such as abnormal noise caused by damage to the rolling bearing.
[0009] Furthermore, even when pressing rolling bearings onto a shaft, a similar problem arises: the cutting dust from the shaft and the wear dust from the rolling bearings and shaft can prevent the rolling bearings from being pressed in perpendicularly to the press-fitting surface.
[0010] Therefore, the present invention aims to provide a rotor having a structure that allows for stable mounting of rolling bearings without being affected by wear particles generated during press-fitting of rolling bearings, and a motor equipped with the rotor. [Means for solving the problem]
[0011] To solve the above problems, the rotor according to the present invention comprises a rotor core, a shaft, and a rolling bearing inserted into the shaft, wherein the rolling bearing comprises a cylindrical inner ring inserted into the shaft, an outer ring disposed on the outer circumference of the inner ring, and a plurality of rolling elements held so as to be rotatable between the outer circumference of the inner ring and the inner circumference of the outer ring, the inner ring has a projection that protrudes in the direction of the cylindrical axis of the cylindrical shape from at least one of the cylindrical axial ends of the cylindrical shape, and a storage space for storing wear particles generated when the inner ring is inserted into the shaft is provided between the projection and the shaft, thereby achieving the intended purpose. [Effects of the Invention]
[0012] According to the present invention, it is possible to provide a rotor that can suppress adverse effects caused by wear particles and the like generated by press-fitting rolling bearings, or a motor equipped with such a rotor. [Brief explanation of the drawing]
[0013] [Figure 1] Cross-sectional view of a motor according to Embodiment 1 of the present invention [Figure 2] Cross-sectional view of a rolling bearing during press-fitting according to Embodiment 1 of the present invention [Figure 3] A top view of a rolling bearing according to Embodiment 1 of the present invention, as seen from the press-fitting jig side. [Figure 4] A top view of a rolling bearing according to Embodiment 1 of the present invention, as seen from the press-fitting jig side. [Figure 5] Enlarged view of the rolling bearing press-fit portion in Figure 2 according to Embodiment 1 of the present invention. [Figure 6] Cross-sectional view of a rolling bearing during press-fitting according to Embodiment 2 of the present invention [Figure 7] A top view of a rolling bearing according to Embodiment 2 of the present invention, as seen from the press-fitting jig side. [Figure 8] A top view of a rolling bearing according to Embodiment 2 of the present invention, as seen from the press-fitting jig side. [Figure 9] Cross-sectional view of a conventional rolling bearing mounting structure.
Best Mode for Carrying Out the Invention
[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are an example of embodying the present invention and do not limit the technical scope of the present invention. Also, throughout all the drawings, the same parts are denoted by the same reference numerals, and the description thereof is omitted after the first time. Further, in each drawing, the details of parts not directly related to the present invention are omitted or simplified.
[0015] (Embodiment 1) The rotor and the motor according to Embodiment 1 of the present invention will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view showing an outline of the internal structure of a motor 1 equipped with a rotor according to the present invention.
[0016] The motor 1 is an inner rotor type DC motor. For example, blades are attached to a shaft, and air is blown by rotating the shaft. In the following description, the side of the mold body top surface 23 (upper side in FIG. 1) will be referred to as the top surface direction as necessary, and the side facing the mold body top surface 23 (the opening side in the mold body 2: lower side in FIG. 1) will be referred to as the bottom surface direction.
[0017] The motor 1 includes a mold body 2, a bracket 6, and a rotor 7.
[0018] The mold body 2 is a hollow cylindrical shape having a circular mold body top surface 23 at one end and an opening at the other end, that is, a concave shape in a cross-sectional view, and the rotor 7 is stored in the internal space of the concave shape. The mold body 2 is formed by processing, for example, resin. The mold body 2 includes a stator 3, a winding 4, and a housing 21a.
[0019] The stator 3 is disposed on the outer periphery of the rotor 7.
[0020] Winding 4 is a conductive wire mainly made of copper or aluminum alloy, and is wound around the stator 3. Winding 4 generates a magnetic field that rotates the rotor 7 when power is supplied.
[0021] The housing 21a is a hollow cylindrical shape that protrudes upward from the center of the top surface 23 of the molded body, and has a concave shape with an open end face in the bottom direction. The housing 21a houses the rolling bearing 5, which will be described later, in the internal space of the concave shape. The housing 21a is formed integrally with the top surface 23 of the molded body. The housing 21a is provided with an insertion hole 24.
[0022] The through-hole 24 is a through-hole provided on the end face of the housing 21a in the direction of the top surface. The through-hole 24 allows the shaft 9, described later, to be inserted from the inside to the outside of the molded body 2. The through-hole 24 is circular and provided at the center of the end face of the housing 21a in the direction of the top surface.
[0023] Bracket 6 is positioned to cover the opening in the bottom direction of the mold body 2. In other words, bracket 6 together with the mold body 2 constitutes the outer casing of the motor 1. Bracket 6 includes a housing 21b.
[0024] Housing 21b is a hollow cylindrical shape having the same size as housing 21a, and is provided protruding from the center of bracket 6 toward the bottom. Housing 21b has a concave shape with an open end face toward the top, and the rolling bearing 5 is housed in the internal space of this concave shape.
[0025] The rotor 7 is rotatably fixed inside the motor 1 by rolling bearings 5, which will be described later. The rotor 7 comprises a shaft 9, a rotor core 11, and permanent magnets 8. When the motor 1 is driven, the shaft 9 acts as the axis of rotation, causing the rotor 7 to rotate.
[0026] The shaft 9 is a cylindrical rod. Here, "cylindrical" means a round tube or cylinder with a circular base. The shaft 9 virtually has a rotation axis 22 that passes through the centers of both end faces of the cylindrical shape. The shaft 9 rotates about the rotation axis 22 as its central axis. The shaft 9 is equipped with a rolling bearing 5 and an E-ring 10.
[0027] The rolling bearing 5 rotatably secures the shaft 9 inside the motor 1. The rolling bearing 5 is a hollow cylindrical shape with an inner diameter equal to the outer diameter of the shaft 9 and an outer diameter equal to the inner diameter of the housings 21a and 21b, which will be described later. One rolling bearing 5 is press-fitted into each end of the shaft 9. Details of the rolling bearing 5 will be described later.
[0028] The E-ring 10 is a locking part that positions the rolling bearing 5 on the shaft 9. The E-ring 10 is, for example, a hollow disc shape having an inner diameter equal to the outer diameter of the shaft 9. One E-ring 10 is provided at a position corresponding to the opening in the mold body 2, and another at a position corresponding to the top surface 23 of the mold body.
[0029] The rotor core 11 is cylindrical in shape, having an inner diameter equal to the outer diameter of the shaft 9, and is inserted into the shaft 9. The rotor core 11 is formed by stacking multiple sheets of electromagnetic steel in the longitudinal direction of the shaft 9 to create its cylindrical shape.
[0030] The permanent magnets 8 are, for example, ferrite sintered magnets and are arranged at equal intervals around the outer circumference of the rotor core 11. The permanent magnets 8 are integrally formed with the rotor core 11 by the connecting members 12.
[0031] The connecting member 12 is, for example, made of resin. Molten resin is poured between the permanent magnet 8 and the rotor core 11 and allowed to solidify, thereby integrating the permanent magnet 8 and the rotor core 11.
[0032] Next, the structure of the rolling bearing 5 will be explained with reference to Figures 1 and 2. Figure 2 is a cross-sectional view showing the movement when the rolling bearing 5 is pressed into the shaft 9.
[0033] In this embodiment, a press-fitting jig 19 is used to insert the rolling bearing 5 onto the shaft 9. The inner diameter of the rolling bearing 5 is the same as the outer diameter of the shaft 9. As shown in Figure 2, the press-fitting jig 19 applies a uniform load to the inner circumferential plane of the cylindrical rolling bearing 5 and presses it in until it reaches the E-ring 10. This fits the rolling bearing 5 onto the shaft 9. Here, the press-fitting direction in Figure 2 is the bottom direction for rolling bearing 5a in Figure 1, and the top direction for rolling bearing 5b in Figure 1.
[0034] The rolling bearing 5 of this embodiment comprises an inner ring 13 and an outer ring 14.
[0035] The inner ring 13 is cylindrical in shape and has an inner diameter equal to the outer diameter of the shaft 9, and is inserted into the shaft 9. The inner ring 13 has an outer diameter smaller than the outer diameter of the E-ring 10. The inner ring 13 is a rotating ring and rotates together with the shaft 9. The inner ring 13 includes a press-fitting jig opposing surface 27, an E-ring opposing surface 28, and a projection 18.
[0036] The press-fitting jig opposing surface 27 is a disc-shaped surface that faces the press-fitting surface of the press-fitting jig 19.
[0037] The E-ring opposing surface 28 is a disc-shaped surface that faces the E-ring 10.
[0038] The projection 18 is provided on the inner ring 13, protruding from the press-fitting jig opposing surface 27 in the opposite direction to the press-fitting direction. In other words, the projection 18 protrudes in the direction of the cylindrical axis of the cylindrical inner ring 13. The projection 18 directly transmits the load from the press-fitting jig 19 only to the inner ring 13 without directly transmitting it to the outer ring 14. The projection 18 is provided on the outer circumference side of the inner circumference end (the part in contact with the shaft 9) on the disc surface of the press-fitting jig opposing surface 27. In other words, the projection 18 is provided at a distance from the shaft 9 in the outer circumference direction. The projection 18 is molded integrally with the inner ring 13, for example. The projection 18 has a press-fit surface 29. The projection 18 also has a storage space 20 between it and the shaft 9. Details of the press-fit surface 29 will be described later.
[0039] The storage space 20 is a space for storing wear particles generated when the rolling bearing 5 is press-fitted. The storage space 20 has a concave shape in cross-section, surrounded by the projection 18, the press-fitting jig opposing surface 27, and the shaft 9, and the opening in this concave shape is provided opposite the press-fitting surface of the press-fitting jig 19.
[0040] The outer ring 14 is cylindrical in shape, having an inner diameter larger than the outer diameter of the E-ring 10 and an outer diameter equal to the outer diameter of the housing 21, and is positioned on the outer circumference of the inner ring 13. The outer ring 14 is a fixed ring and does not rotate with the shaft 9.
[0041] Furthermore, U-shaped grooves 26 are provided on the outer circumference of the inner ring 13 and the inner circumference of the outer ring 14, respectively, to hold the rolling elements 15, which will be described later.
[0042] Furthermore, the outer circumference of the inner ring 13 and the inner circumference of the outer ring 14 are provided with rolling elements 15, a cage 16, and a shield 17. Grease is filled between the outer circumference of the inner ring 13 and the inner circumference of the outer ring 14 to reduce wear of the rolling elements 15. For example, known grease for rolling bearings can be used.
[0043] The U-shaped channel 26 is provided around the entire circumference of the outer ring 13 and the inner ring 14.
[0044] The rolling elements 15 are formed, for example, as spherical metals. Multiple rolling elements 15 are held so as to be able to roll between two U-shaped grooves 26 provided on the outer circumference of the inner ring 13 and the inner circumference of the outer ring 14.
[0045] The retainer 16 is a component provided to maintain a constant circumferential spacing between the multiple rolling elements 15. The retainer 16 clamps the rolling elements 15 from the press-fitting jig opposing surface 27 and the E-ring opposing surface 28.
[0046] The shield 17 is hollow and disc-shaped. The shield 17 is provided at both ends of the rolling bearing 5, with its inner circumference coinciding with the outer circumference of the inner ring 13 and its outer circumference coinciding with the inner circumference of the outer ring 14. In other words, the shield 17 is positioned to cover the openings at both ends of the rolling bearing 5 formed by the inner ring 13 and the outer ring 14.
[0047] Next, the structure of the projection 18 will be described in detail with reference to Figures 3 and 4. Figures 3 and 4 are top views of the rolling bearing 5 as seen from the press-fitting jig 19 side.
[0048] The projection 18 is provided around the entire circumference of the press-fitting jig opposing surface 27, which is a disc surface located on the outer circumference side of the inner ring 13, as shown in Figure 3. This configuration allows the press-fitting jig 19 to apply an even load to the inner ring 13 when the rolling bearing 5 is pressed onto the shaft 9. Furthermore, the projection 18 does not necessarily need to be provided around the entire circumference of the press-fitting jig opposing surface 27; it can be provided in any way that allows the press-fitting jig 19 to apply an even load to the cylindrical plane of the inner ring 13. For example, as shown in Figure 4, the projection 18 may be provided at least at two points symmetrically with respect to the center 30 of the disc surface of the press-fitting jig opposing surface 27 as the center of symmetry, or at least at two points symmetrically with respect to the diameter 31 of the disc surface as the axis of symmetry. With these configurations, when the rolling bearing 5 is pressed onto the shaft 9, the press-fitting jig 19 can always apply a uniform load to only the inner ring 13, thereby preventing damage to the rolling elements 15.
[0049] Next, the effects of the projection 18 and the storage space 20 will be explained with reference to Figure 5.
[0050] The projection 18 is parallel to the press-fitting jig opposing surface 27 at its protruding tip and has a press-fit surface 29 that faces the press-fitting surface of the press-fitting jig 19. In other words, the press-fit surface 29 is a plane perpendicular to the cylindrical axis direction on the cylindrical inner ring 13. By having the press-fit surface 29, the projection 18 makes it possible to further equalize the load from the press-fitting jig 19 to the inner ring 13.
[0051] Furthermore, as mentioned in the problem section, conventionally, the rolling bearing 5 could not be pressed perpendicularly against the press-fitting jig's opposing surface 27 due to wear particles generated by friction with the shaft during insertion.
[0052] To address the above issues, the storage space 20 is provided as a concave space between it and the shaft 9 by the projection 18, and the opening in this concave shape faces the press-fitting jig 19. In other words, as shown in Figure 5, even if wear particles are generated by friction between the shaft 9 and the inner ring 13, and even if wear particles adhere to the press-fitting surface of the press-fitting jig 19, the part of the press-fitting jig 19 to which the wear particles have adhered, in other words, the wear particles themselves, are stored in the storage space 20. Therefore, the press-fitting jig 19 can stably mount the rolling bearing 5 without being affected by the wear particles, that is, without disrupting the uniform pressing pressure. In addition, the projection 18 prevents the wear particles stored in the storage space 20 from entering the inside of the rolling bearing 5.
[0053] This configuration makes it possible to provide a rotor with a structure that allows for the stable mounting of rolling bearings without being affected by wear particles generated by the press-fitting of rolling bearings, and a motor equipped with the rotor.
[0054] (Embodiment 2) A rotor and motor according to Embodiment 2 of the present invention will be described with reference to Figure 6. Figure 6 is a cross-sectional view showing the movement when the rolling bearing 5 according to Embodiment 2 is pressed into the housing 21.
[0055] The motor 1 according to Embodiment 2 is an outer rotor type. Therefore, the rotor 7 comprises a housing 21, a rotor core 11, and a permanent magnet 8. For example, blades are attached to the housing 21, and air is blown by rotating the housing 21.
[0056] In the rolling bearing 5 according to this embodiment, the outer ring 14 is a rotating ring that rotates together with the housing 21.
[0057] The outer ring 14 has a press-fitting jig facing surface 27 and is equipped with a projection 18 that protrudes from the press-fitting jig facing surface 27 in the opposite direction to the press-fitting direction. In other words, the projection 18 protrudes in the direction of the cylindrical axis of the cylindrical outer ring 14.
[0058] The projection 18 is provided to apply the load from the press-fitting jig 19 only to the outer ring 14 and not to the inner ring 13. The projection 18 is provided on the inner circumference side of the outer circumference end (the part in contact with the housing 21) of the disc surface of the press-fitting jig facing surface 27. In other words, the projection 18 is provided spaced inward from the housing 21. The projection 18 is, for example, molded integrally with the outer ring 14. The projection 18 has a press-fit surface 29. The projection 18 also has a storage space 20 between it and the housing 21.
[0059] The storage space 20 is a space for storing wear particles generated when the rolling bearing 5 is press-fitted. The storage space 20 has a concave shape in cross-section, surrounded by the projection 18, the press-fitting jig facing surface 27, and the housing 21, and the opening in this concave shape is provided facing the press-fitting surface of the press-fitting jig 19.
[0060] With these configurations, similar to Embodiment 1, the press-fit jig 19 can stably mount the rolling bearing 5 without being affected by wear particles. In addition, the projection 18 prevents wear particles stored in the storage space 20 from entering the inside of the rolling bearing 5.
[0061] Next, the structure of the projection 18 will be described in detail with reference to Figures 7 and 8. Figures 7 and 8 are top views of the rolling bearing 5 according to Embodiment 2, as seen from the press-fitting jig 19 side.
[0062] The projection 18 is provided around the entire circumference of the press-fitting jig opposing surface 27, which is a disc surface located on the inner circumference side of the outer ring 14, as shown in Figure 7. This configuration allows the press-fitting jig 19 to apply an even load to the outer ring 14 when the rolling bearing 5 is pressed into the housing 21. Furthermore, the projection 18 does not necessarily need to be provided around the entire circumference of the press-fitting jig opposing surface 27; it can be provided in any way that allows the press-fitting jig 19 to apply an even load to the outer ring 14. For example, as shown in Figure 8, the projection 18 may be provided at least at two locations with point symmetry around the center 30 on the disc surface of the press-fitting jig opposing surface 27 as the center of symmetry, or at least at two locations with line symmetry around the diameter 31 of the disc surface as the axis of symmetry. With these configurations, when the rolling bearing 5 is pressed into the housing 21, the press-fitting jig 19 can always apply a uniform load to only the outer ring 14, thereby preventing damage to the rolling elements 15.
[0063] Therefore, even if the motor 1 is of the outer rotor type, it is possible to provide a rotor having a structure that allows the rolling bearing to be stably mounted without being affected by wear particles generated by the press-fitting of the rolling bearing, and a motor equipped with the rotor. [Industrial applicability]
[0064] A motor equipped with the rotor according to the present invention can be applied, for example, to a drive motor for a ventilation fan. [Explanation of Symbols]
[0065] 1: Motor 2: Mold 3: Status 4: Winding 5: Rolling bearings 6: Bracket 7: Rotor 8: Permanent magnets 9: Shaft 10: E-ring 11: Rotor core 12: Connecting member 13: Inside 14: Outer ring 15: Rolling element 16:Retainer 17: Shield 18:Protrusion 19: Press-fitting jig 20: Storage space 21: Housing 22: Rotation axis 23: Top surface of the mold 24: Through hole 26:U-shaped groove 27: Opposing surfaces of press-fitting jig 28: E-ring opposing surface 29: Press-fit surface 30: Center 31: Diameter 102: Rolling bearings 103: Frame 112: Bearing housing 113: Open end 114: Positioning section
Claims
1. A rotor comprising a rotor core, a shaft, and a rolling bearing inserted into the shaft, The aforementioned rolling bearing is, A cylindrical inner ring inserted into the aforementioned shaft, An outer ring is positioned on the outer circumference of the inner ring, It comprises a plurality of rolling elements that are held so as to be rotatable between the outer circumference of the inner ring and the inner circumference of the outer ring, The aforementioned inner ring is When pressing in the aforementioned rolling bearing, the press-fitting jig's opposing surface faces the press-fitting surface, The press-fitting jig has a projection that protrudes from the opposing surface toward the opposite side of the press-fitting direction, Between the aforementioned projection and the shaft, A motor equipped with a storage space for storing wear particles generated when the inner ring is inserted into the shaft.
2. A rotor comprising a rotor core, a housing, and rolling bearings inserted into the housing, The aforementioned rolling bearing is, A cylindrical outer ring inserted into the aforementioned housing, An inner ring positioned on the inner circumference of the outer ring, It comprises a plurality of rolling elements that are held so as to be rotatable between the outer circumference of the inner ring and the inner circumference of the outer ring, The aforementioned outer ring is When pressing in the aforementioned rolling bearing, the press-fitting jig's opposing surface faces the press-fitting surface, The press-fitting jig has a projection that protrudes from the opposing surface toward the opposite side of the press-fitting direction, Between the aforementioned projection and the housing, A motor having a storage space for storing wear particles generated when the outer ring is inserted into the housing.
3. The aforementioned projection is The motor according to claim 1 or 2, wherein the tip has a plane perpendicular to the direction of the cylindrical axis in the cylindrical shape.
4. The aforementioned projection is The motor according to any one of claims 1 to 3, wherein at least two are provided in a point-symmetric manner with respect to the center of the disc surface in the cylindrical shape as the center of symmetry.
5. The aforementioned projection is The motor according to any one of claims 1 to 3, wherein at least two are provided symmetrically with respect to the diameter of the disc surface in the cylindrical shape as the axis of symmetry.
6. The aforementioned projection is The motor according to any one of claims 1 to 3, provided over the entire circumference of the disc surface in the cylindrical shape.
7. The aforementioned projection is The motor according to claim 1, which is integrally molded with the inner ring.
8. The aforementioned projection is The motor according to claim 2, which is integrally molded with the outer ring.