Rotor and manufacturing method for the same

Abstract

To provide a rotor and a manufacturing method for the same, capable of suppressing oil from reaching an outer surface of a slip ring.SOLUTION: The rotor includes: a rotor body 1 provided with a field coil 12; a shaft 2 fixed to the rotor body 1 and forming a rotational axis z; a first resin-molded body 31 covering an outer circumferential surface of the shaft 2 protruding from the rotor body 1 in a direction of the rotational axis z; a slip ring 32 disposed on the outer circumferential surface of the first resin-molded body 31; and a bus bar 33 having one end electrically connected to the slip ring 32 within the first resin-molded body 31 and the other end protruding from the first resin-molded body 31, and electrically connected to the field coil 12. The entire other end of the bus bar 33 protruding from the first resin-molded body 31 is sealed by a second resin-molded body 4 that is separate from the first resin-molded body 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a rotor and a method for manufacturing the same. [Background technology]

[0002] A rotor is known that supplies power to a field coil attached to a rotor core via a slip ring that contacts the brushes. Current flows from the brushes to the slip ring, and from the slip ring to the field coil via a connection terminal (hereinafter referred to as a bus bar). Oil is supplied to the rotor for cooling and lubrication. However, this oil can cause poor electrical connection between the brushes and the slip ring. Oil adhering to the field coil attached to the rotor core travels by capillary action along the bus bar held in the resin molded body, and flows from the coil side to the slip ring side within the resin molded body. Once the oil reaches the slip ring side, it reaches the outer surface of the slip ring through the gap between the resin molded body and the slip ring. In other words, an oil film forms on the outer surface of the slip ring that contacts the brushes, causing poor electrical connection between the brushes and the slip ring.

[0003] To address this problem, Patent Document 1 discloses a structure in which protrusions are provided on the side surfaces of the slip ring that come into contact with the resin molded body, thereby preventing oil from reaching the outer peripheral surface of the slip ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-202624 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors discovered the following problem with the rotor disclosed in Patent Document 1. While the rotor is in operation, the slip rings are continuously subjected to stress due to contact with the brushes. As a result, the slip rings are deformed by wear and stress, and gaps are formed between the projections on the side surfaces of the slip rings and the resin molded body, which can allow oil to reach the outer periphery of the slip rings.

[0006] The present disclosure has been made to solve such problems, and provides a rotor that can prevent oil from reaching the outer peripheral surface of a slip ring, and a manufacturing method thereof. [Means for solving the problem]

[0007] A rotor according to the present disclosure includes a rotor body including a field coil, a shaft fixed to the rotor body and constituting a rotation axis, a first resin molded body covering an outer peripheral surface of the shaft protruding from the rotor body in the direction of the rotation axis, a slip ring mounted on the outer peripheral surface of the first resin molded body, and a bus bar having one end electrically connected to the slip ring within the first resin molded body and the other end protruding from the first resin molded body and electrically connected to the field coil, wherein the other end of the bus bar protruding from the first resin molded body is entirely sealed in a second resin molded body separate from the first resin molded body, thereby preventing oil from reaching the outer peripheral surface of the slip ring.

[0008] The field coil may have coil end portions at both ends of the rotor body in the direction of the rotation axis, and the coil end portion on the first resin molded body side may be fixed to the second resin molded body.

[0009] The field coil may be sealed in the second resin molded body within the rotor body.

[0010] The rotor manufacturing method according to the present disclosure includes the steps of integrating a slip ring and a bus bar into a first resin molded body, covering the outer surface of a shaft with the first resin molded body, and fixing the shaft constituting a rotating shaft to a rotor body and protruding the first resin molded body from the rotor body in the direction of the rotating shaft, wherein one end of the bus bar sealed within the first resin molded body is electrically connected to the slip ring installed on the outer surface of the first resin molded body, and the other end of the bus bar protruding from the first resin molded body is electrically connected to a field coil provided on the rotor body, and the other end of the bus bar protruding from the first resin molded body is entirely sealed with a second resin molded body separate from the first resin molded body. [Effects of the Invention]

[0011] The present disclosure makes it possible to provide a rotor that can prevent oil from reaching the outer peripheral surface of a slip ring, and a method for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of a rotor according to the present disclosure. [Figure 2] FIG. 2 is a perspective view of the rotor according to the present disclosure with the second resin molded body removed. [Figure 3] FIG. 3 is a perspective view of a rotor according to the present disclosure. [Figure 4] FIG. 4 is a plan view of a rotor according to the present disclosure. [Figure 5] FIG. 5 is a flowchart of a method for manufacturing a rotor according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiment 1 Hereinafter, a rotor and a manufacturing method thereof according to the present disclosure will be described with reference to the drawings.

[0014] <Rotor configuration> First, the configuration of a rotor according to the present disclosure will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a cross-sectional view of a rotor according to the present disclosure. Fig. 2 is a perspective view of a rotor according to the present disclosure with a second resin molded body removed. Fig. 3 is a perspective view of a rotor according to the present disclosure. Fig. 4 is a plan view of a rotor according to the present disclosure.

[0015] As shown in FIG. 1, the rotor 100 includes a rotor body 1, a shaft 2, a slip ring device 3, and a second resin molded body 4.

[0016] The rotor body 1 rotates around a rotation axis (z-axis) formed by the shaft 2. The rotor body 1 includes a rotor core 11 and a field coil 12. The rotor core 11 is a magnetic member. As shown in FIG. 2, the rotor core 11 has a plurality of protrusions 11a arranged on its outer periphery and a shaft hole in its center to which the shaft 2 is fixed. The field coil 12 is a winding wound in an annular shape around the outer periphery of the protrusions 11a of the rotor core 11, and generates a magnetic field. Coil end portions 121, which are part of the field coil 12, protrude from both axial ends of the rotor core 11 about the rotation axis (z-axis).

[0017] Furthermore, in at least two protruding portions 11a of the rotor core 11, a lead wire (not shown) extends from one end of the field coil 12 provided in the protruding portion 11a for electrical connection to the bus bar 33. A crossover wire (not shown) extends from the other end of the field coil 12 provided with the lead wire and from both ends of the field coil 12 provided in the other protruding portions 11a. The field coils 12 provided in the protruding portions 11a adjacent to each other in the circumferential direction of the rotation axis (z-axis) are electrically connected to each other by the crossover wire.

[0018] The shaft 2 is a rod-shaped member fixed to the rotor body 1 and constituting the rotation axis (z-axis). The shaft 2 includes a main shaft 21 and a sub-shaft 22. The shaft 2 rotates integrally with the rotor body 1, the slip ring device 3, and the second resin molded body 4. The main shaft 21 and the sub-shaft 22 may be cylindrical members.

[0019] The slip ring device 3 includes a first resin molded body 31, a slip ring 32, and a bus bar 33. The slip ring device 3 is fixed to a shaft 2 that protrudes from the rotor body 1 in the direction of the rotation axis (z-axis).

[0020] The first resin molded body 31 is formed so as to cover the outer peripheral surface of the shaft 2 protruding from the rotor body 1 in the direction of the rotation axis (z-axis). The first resin molded body 31 is fixed to the shaft 2, for example, by being press-fitted into the shaft 2. The first resin molded body 31 is formed by molding an insulating resin. The first resin molded body 31 rotates integrally with the shaft 2. The first resin molded body 31 includes a slip ring 32 and a bus bar 33.

[0021] The slip ring 32 is an annular member disposed on the outer circumferential surface of the first resin molded body 31. The material of the slip ring 32 is, for example, a copper-based metal with excellent electrical conductivity. The slip ring 32 rotates integrally with the first resin molded body 31 while making contact with a brush (not shown) on the outer circumferential surface of the slip ring 32. A current is supplied to this brush from, for example, a motor control device. The supplied current is supplied to the field coil 12 provided in the rotor body 1 via the brush, the slip ring 32, and the bus bar 33. This generates a magnetic field in the field coil 12 of the rotor body 1.

[0022] The bus bar 33 electrically connects the slip ring 32 and the field coil 12. Specifically, one end of the bus bar 33 is electrically connected to the slip ring 32 inside the first resin molded body 31, and the other end protrudes from the first resin molded body 31 and is electrically connected to the field coil 12. The bus bar 33 is connected to the slip ring 32 and the field coil 12 by, for example, welding. The material of the bus bar 33 is, for example, a copper-based metal with excellent electrical conductivity.

[0023] The second resin molded body 4 is disposed on the outer peripheral surface of the first resin molded body 31, spaced apart from the slip ring in the axial direction of the rotation axis (z-axis). The second resin molded body 4 is formed by molding an insulating resin. The second resin molded body 4 entirely seals the other end of the bus bar 33 protruding from the first resin molded body 31. The bus bar 33 is electrically connected to the field coil 12 while sealed in the second resin molded body 4, which is separate from the first resin molded body 31. In other words, the bus bar 33 is electrically connected to the slip ring 32 and the field coil 12 while sealed in the first resin molded body 31 and the second resin molded body 4. This configuration prevents oil supplied to the rotor body 1 from adhering to the bus bar 33. Therefore, oil does not flow down the bus bar 33 by capillary action and leak into the slip ring 32 through a small gap. This prevents oil from reaching the outer peripheral surface of the slip ring 32.

[0024] 1 and 3, in the first embodiment, the second resin molded body 4 has a shape that seals the field coil 12 inside the rotor body 1. However, the shape of the second resin molded body 4 is not limited to this. For example, the second resin molded body 4 may have a shape that fixes only the coil end portion 121 of the field coil 12 on the first resin molded body 31 side.

[0025] 4, second resin molded body 4 is formed in a circular shape when rotor 100 is viewed from above, but is not limited to this. For example, second resin molded body 4 may have a shape that seals only the other end of busbar 33 protruding from first resin molded body 31. Similarly, first resin molded body 31 is also formed in a circular shape when rotor 100 is viewed from above, but is not limited to this. Note that FIG. 4 is a plan view of rotor 100 as viewed from the z-axis positive side.

[0026] <Rotor manufacturing method> Next, a method for manufacturing a rotor according to the present embodiment 1 will be described. Fig. 5 is a flowchart of the method for manufacturing a rotor according to the present disclosure. Note that the order of the steps is not limited to this, and may be changed as appropriate.

[0027] First, the slip ring 32 and the bus bar 33 are integrated with the first resin molded body 31 (step S101). In this step S101, the slip ring 32 and the bus bar 33 are connected in advance. For example, one end of the bus bar 33 is connected to the inner circumferential surface of the slip ring 32 by welding. Next, the connected slip ring 32 and bus bar 33 are placed at a predetermined position in a mold (not shown). Then, molten resin is injected into the mold and solidified to form the first resin molded body 31, and the slip ring 32 and the bus bar 33 are integrated with the first resin molded body 31. After the slip ring 32 and the bus bar 33 are integrated with the first resin molded body 31, the outer circumferential surface of the slip ring 32 and the other end of the bus bar 33 are exposed from the first resin molded body 31. In step S101, the slip ring 32 and the bus bar 33 are integrated with the first resin molded body 31 to form the slip ring device 3.

[0028] Next, the outer peripheral surface of the shaft 2 is covered with the first resin molded body 31 (step S102). More specifically, the slip ring device 3 is fixed to the shaft 2 so as to cover the outer peripheral surface of the shaft 2. For example, the slip ring device 3 may be fixed to the shaft 2 by press-fitting the first resin molded body 31 of the slip ring device 3 into the shaft 2, but this is not limiting.

[0029] Next, the shaft 2 constituting the rotation axis (z-axis) is fixed to the rotor body 1 (step S103). In this step S103, the shaft 2 is fixed to the rotor body 1 so that the slip ring device 3 protrudes from the rotor body 1 in the axial direction of the rotation axis (z-axis). Here, the field coil 12 may be wound in an annular shape around the outer peripheral surface of the protruding portion 11a of the rotor core 11 either before or after the shaft 2 is fixed to the rotor body 1.

[0030] Next, the other end of the bus bar 33 protruding from the first resin molding body 31 is connected to the field coil 12 (step S104). More specifically, a lead wire (not shown) of the field coil 12 is connected to the other end of the bus bar 33 protruding from the first resin molding body 31.

[0031] Next, the other end of the bus bar 33 protruding from the first resin molded body 31 is entirely sealed with the second resin molded body 4 (step S105). For example, the rotor 100 including the rotor main body 1, the shaft 2, and the slip ring device 3 is placed at a predetermined position in a mold (not shown). Then, a molten second resin molded body 4 is injected into the mold and solidified, thereby entirely sealing the other end of the bus bar 33 protruding from the first resin molded body 31 with the second resin molded body 4. The shape of the rotor 100 after sealing may be, for example, a shape in which the field coil 12 is sealed with the second resin molded body 4 inside the rotor main body 1, or a shape in which only the coil end portion 121 of the field coil 12 is fixed to the second resin molded body 4. Alternatively, only the other end of the bus bar 33 protruding from the first resin molded body 31 may be entirely sealed with the second resin molded body 4.

[0032] As described above, according to the rotor and manufacturing method thereof disclosed herein, the bus bar 33 is electrically connected to the slip ring 32 and the field coil 12 while being sealed between the first resin molded body 31 and the second resin molded body 4. This configuration can prevent oil supplied to the rotor body 1 from adhering to the bus bar 33. This can prevent oil from reaching the outer peripheral surface of the slip ring 32.

[0033] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention.

[0034] For example, although the first embodiment illustrates an example in which there are two pairs of slip rings 32 and bus bars 33, the present invention is not limited to this. For example, if the field coil 12 of the rotor body 1 is three-phase, there will be three pairs of slip rings 32 and bus bars 33. In other words, the rotor 100 includes two or more pairs of slip rings 32 and bus bars 33. [Explanation of symbols]

[0035] 1 Rotor body 2 shafts 3. Slip ring device 4 Second resin molded body 11 Rotor core 11a Projection 12 Field coil 21 Main shaft 22 Sub-shaft 31 First resin molded body 32 slip ring 33 Bus Bar 100 rotors 121 Coil end z axis of rotation

Claims

1. a rotor body including a field coil; a shaft fixed to the rotor body and constituting a rotation axis; a first resin molded body covering an outer peripheral surface of the shaft protruding from the rotor body in the direction of the rotation axis; a slip ring disposed on an outer peripheral surface of the first resin molded body; a bus bar having one end electrically connected to the slip ring within the first resin molding body and the other end protruding from the first resin molding body and electrically connected to the field coil; A rotor comprising: the other end of the bus bar protruding from the first resin molded body is entirely sealed in a second resin molded body that is separate from the first resin molded body; Rotor.

2. the field coil has coil end portions at both ends of the rotor body in the direction of the rotation axis, The coil end portion on the side of the first resin molded body is fixed to the second resin molded body. The rotor of claim 1 .

3. the field coil is sealed in the second resin molded body within the rotor body; The rotor of claim 2 .

4. Integrating the slip ring and the bus bar into a first resin molding body; covering an outer circumferential surface of a shaft with the first resin molded body; a step of fixing the shaft constituting a rotation axis to a rotor body and causing the first resin molded body to protrude from the rotor body in a direction of the rotation axis; A method for manufacturing a rotor comprising: one end of the bus bar sealed in the first resin molding is electrically connected to the slip ring installed on the outer circumferential surface of the first resin molding, and the other end of the bus bar protruding from the first resin molding is electrically connected to a field coil provided in a rotor body, the other end of the bus bar protruding from the first resin molded body is entirely sealed with a second resin molded body that is separate from the first resin molded body. A method for manufacturing a rotor.

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