JP2021035278A - Electric motor and manufacturing method of the same - Google Patents

Abstract

To provide an electric motor which achieves reduction of a possibility of failure caused by an excessive impregnant, and to provide a manufacturing method of the electric motor.SOLUTION: An electric motor 10 includes: a housing 14 which is attached to a stator 12 so as to cover a coil 22 and has a through hole 24 in which a shaft 18 is disposed; and a seal member 30 which seals a gap between the shaft 18 disposed in the through hole 24 and the housing 14. The housing 14 is formed with communication holes 26 which allow a stator 12 side inner surface 14a in the housing 14 and the through hole 24 to communicate with each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electric motor and a method for manufacturing the electric motor in which the risk of defects due to an excessive impregnating agent is reduced.

As disclosed in Patent Document 1, a motor (electric motor) including a stator, housings joined to both ends of the stator, and a varnish (impregnating agent) is known. The impregnating agent is often provided in the electric motor mainly for the purpose of impregnating the coil of the stator. In Patent Document 1, the impregnating agent is filled in the annular groove surrounding the shaft core formed on the contact surface of the housing in contact with the stator so that water or oil can enter the inside of the electric motor from the joint portion. It is preventing.

Japanese Unexamined Patent Publication No. 7-177698

Patent Document 1 proposes a structure of an electric motor for incorporating a large amount of an impregnating agent into the electric motor. However, if the excess impregnating agent remains in the motor, it causes a defect. The defect is that, for example, a part of the cured excess impregnant is broken into fragments by the vibration generated in the electric motor, and the coil provided in the stator comes into contact with the fragments and is damaged.

Therefore, an object of the present invention is to provide an electric motor and a method for manufacturing the electric motor in which the risk of defects due to an excessive impregnating agent is reduced.

One aspect of the invention is an electric motor.
A stator with a coil and
A rotor surrounded by the stator and to which a shaft is attached,
A housing that is attached to the stator so as to cover the coil and has a through hole in which the shaft is arranged.
The impregnating agent impregnated in the coil and
A sealing member that seals the gap between the shaft and the housing arranged in the through hole, and
With
The housing is formed with a communication hole that communicates the inner surface of the housing on the stator side with the through hole.

Another aspect of the invention is a method of manufacturing an electric motor.
The mounting process of mounting a housing with a through hole through which a rotor with a shaft is mounted to a stator provided with a coil, and
After the mounting step, a dipping step of immersing the stator and the housing in an impregnating agent, and
After the dipping step, the excess impregnating agent in the stator is discharged from the communication hole and the through hole formed in the housing, which communicate with the inner surface of the housing on the stator side and the through hole. Discharge process and
After the discharge step, a curing step of curing the impregnating agent impregnated in the coil and a curing step of curing the impregnating agent.
After the curing step, a mounting step of mounting the rotor on the stator and a mounting step.
After the mounting step, a sealing step of sealing the gap between the shaft and the housing arranged in the through hole with a sealing member,
including.

According to the present invention, there is provided an electric motor and a method for manufacturing the electric motor in which the risk of defects due to an excessive impregnating agent is reduced.

It is sectional drawing of the electric motor of an embodiment. It is a flowchart which showed a part of the manufacturing method of the electric motor of embodiment. It is sectional drawing which shows the state (1) during manufacturing of the electric motor of an embodiment. It is sectional drawing which shows the state (2) during manufacturing of the electric motor of an embodiment. It is sectional drawing of the electric motor of modification 1. FIG.

Hereinafter, preferred embodiments of the present invention will be given and described in detail with reference to the accompanying drawings.

[Embodiment]
FIG. 1 is a cross-sectional view of the electric motor 10 of the embodiment.

The electric motor 10 includes a stator 12 provided with a coil 22, a housing 14 attached to the stator 12 so as to cover the coil 22, and an impregnating agent 16 impregnated in the coil 22. The stator 12 of the present embodiment is a cylindrical part arranged so as to surround the shaft 18 which is the rotation shaft of the electric motor 10 and the rotor 20 to which the shaft 18 is attached. In FIG. 1, the shaft 18 and the rotor 20 are shown by an alternate long and short dash line. The shape of the stator 12 of the present embodiment is not limited to a cylindrical shape as long as it can surround the shaft 18 and the rotor 20.

The coil 22 provided on the stator 12 has coil ends 22a on both ends (one end 12a, the other end 12b) of the stator 12 in the axial direction of the shaft 18. By passing an electric current through the coil 22, torque is generated in the rotor 20, and the torque causes the shaft 18 to rotate.

The housing 14 covers both ends 12a and 12b of the stator 12 together with the coil 22. This prevents, for example, the possibility that the coil end 22a comes into contact with an external object and is damaged.

Each of the housing 14 covering one end 12a side of the stator 12 and the housing 14 covering the other end 12b side of the stator 12 is formed so as to have a recess. The cross section having the recess may be Π-shaped.

Each of the housing 14 covering one end 12a side of the stator 12 and the housing 14 covering the other end 12b side of the stator 12 has an inner surface 14a and an outer surface 14b. The inner surface 14a is the surface of the recess provided in the housing 14, in other words, the surface on the side that covers the stator 12. The outer surface 14b is a surface opposite to the inner surface 14a.

Each of the housing 14 covering one end 12a side of the stator 12 and the housing 14 covering the other end 12b side of the stator 12 has a through hole 24 for arranging the shaft 18. The through hole 24 penetrates between the inner surface 14a and the outer surface 14b, and the shaft 18 and the rotor 20 can be inserted therethrough.

A communication hole 26 that communicates the inner surface 14a and the through hole 24 is formed in the housing 14 that covers one end 12a side of the stator 12. The one end 12a side of the stator 12 is opposite to the side to which the encoder is attached to the stator 12.

As shown in FIG. 1, the number of the communication holes 26 may be two, one, or three or more. That is, at least one communication hole 26 is formed in the housing 14 that covers one end 12a side of the stator 12. When there are a plurality of communication holes 26, it is preferable that the communication holes 26 are arranged symmetrically with respect to the axis of the through holes 24. In FIG. 1, two communication holes 26 are arranged line-symmetrically with respect to the axis of the through hole 24.

At least one communication hole 26 formed in the housing 14 covering one end 12a side of the stator 12 may have an inclined portion 26SL as shown in FIG. The inclined portion 26SL is a portion that inclines from the opening 26OP on the through hole 24 side in the communication hole 26 toward the inner surface 14a of the housing 14 so as to move away from the through hole 24.

In the present embodiment, the impregnating agent 16 may be a varnish containing an insulating resin as a material, or may be an ester-based solvent-free material. The impregnant 16 is cured while being filled between the wires of the coil 22. Thereby, for example, the coil 22 is satisfactorily fixed to the stator 12. Further, the impregnating agent 16 is cured in a state of being filled in the gap 28 between the stator 12 and the housing 14. As a result, the stator 12 and the housing 14 are joined by the impregnating agent 16, and oil and water are prevented from entering the inside of the electric motor 10 through the gap 28 between the stator 12 and the housing 14.

In the present embodiment, the amount of the impregnating agent 16 adhering to the place excluding the gap 28 between the stator 12 and the housing 14 and the line between the coils 22 is minimized. That is, the electric motor 10 is not impregnated with the excess impregnating agent 16. Therefore, in the motor 10, the possibility that debris of the cured impregnant 16 is generated inside the motor 10 is minimized, and members such as the coil 22 provided inside the motor 10 are damaged by contact with the debris. The risk of sticking is also minimized. In this way, the motor 10 is less likely to be defective due to the excess impregnating agent 16.

The electric motor 10 further includes a sealing member 30 that seals a gap between a housing 14 that covers one end 12a side of the stator 12 and a shaft 18 arranged in a through hole 24 of the housing 14. As a result, it is possible to prevent water or oil from entering the housing 14 from one end 12a side of the stator 12. The seal member 30 may be an O-ring.

An encoder is attached to the housing 14 that covers the other end 12b side of the stator 12, and the encoder prevents water or oil from entering the housing 14 from the one end 12a side of the stator 12. Therefore, the gap between the housing 14 that covers the other end 12b side of the stator 12 and the shaft 18 arranged in the through hole 24 of the housing 14 does not have to be sealed by the sealing member 30.

In the present embodiment, the opening 26OP on the through hole 24 side of the communication hole 26 formed in the housing 14 is located closer to the stator 12 than the seal member 30. Therefore, even if the communication hole 26 is not closed, it is possible to prevent water or oil from entering the housing 14. Therefore, a dedicated member for closing the opening 26OP is unnecessary, and the number of parts can be reduced. The opening 26OP on the through hole 24 side of the communication hole 26 formed in the housing 14 may be closed by the seal member 30.

Next, a method of manufacturing the electric motor 10 will be described with reference to FIGS. 2 to 4.
FIG. 2 is a flowchart showing a part of the manufacturing method of the electric motor 10 of the embodiment, FIG. 3 is a cross-sectional view showing a state (1) during manufacturing of the electric motor 10 of the embodiment, and FIG. 4 is a cross-sectional view. It is sectional drawing which shows the state (2) during manufacturing of the electric motor 10 of embodiment.

As a premise, it is assumed that the work of molding the housing 14 and the work of providing the coil 22 on the stator 12 have been completed in advance.

First, the housing 14 is attached to the stator 12 (attachment step S1). In the present embodiment, the housing 14 is attached to both ends 12a and 12b of the stator 12 in the axial direction. As a result, both ends 12a and 12b of the stator 12 are covered by the housing 14 together with the coil ends 22a.

When the mounting step S1 is completed, as shown in FIG. 3, the stator 12 is surrounded by the stator 12, the housing 14 that covers one end 12a side of the stator 12, and the housing 14 that covers the other end 12b side of the stator 12. Space 32 is formed. The space 32 communicates with the outside through a gap 28 (FIG. 4) between the stator 12 and the housing 14, and a through hole 24 and a communication hole 26 formed in the housing 14.

Next, the stator 12 and the housing 14 are immersed in the impregnating agent 16 (immersion step S2). In this step, the impregnating agent 16 enters the space 32 through the gap 28 between the stator 12 and the housing 14, and the through hole 24 and the communication hole 26 formed in the housing 14. As a result, the impregnating agent 16 reaches the coil 22 and impregnates between the lines of the coil 22.

Next, the excess impregnating agent 16 in the space 32 is discharged to the outside through the through hole 24 and the communication hole 26 (discharge step S3). The "extra impregnant 16" remains in the space 32 except for the impregnant 16 impregnated in the gap 28 between the stator 12 and the housing 14 and the impregnant 16 impregnated between the lines of the coil 22. Refers to the impregnant 16.

In this step, the stator 12 and the housing 14 are pulled up from the impregnating agent 16. After that, the stator 12 and the housing 14 arranged so that the through hole 24 is located below the stator 12 in the direction of gravity are left to stand until a predetermined period of time elapses. As a result, the excess impregnating agent 16 is naturally discharged to the outside through the through hole 24 according to gravity. At this time, the communication hole 26 that communicates the inner surface 14a and the through hole 24 is formed, so that the impregnating agent 16 is discharged.

The impregnating agent 16 impregnated in the gap 28 between the stator 12 and the housing 14 remains without falling out of the gap 28 due to the surface tension acting on the impregnating agent 16 in the gap 28 or the viscosity of the impregnating agent 16 itself. .. Similarly, the impregnating agent 16 impregnated between the lines of the coil 22 remains without falling out of the lines of the coil 22 due to the surface tension acting on the impregnating agent 16 between the lines of the coil 22 or the viscosity of the impregnating agent 16 itself. To do. As a result, the configuration shown in FIG. 4 is obtained.

Next, the impregnating agent 16 impregnated in the gap 28 between the stator 12 and the housing 14 is cured (curing step S4). By curing the impregnating agent 16, oil and water are prevented from entering the space 32 through the gap 28 between the stator 12 and the housing 14. The impregnant 16 may be cured by heating.

Next, the rotor 20 is mounted on the stator 12 (mounting step S5).
In this step, the rotor 20 is arranged at a predetermined position surrounded by the stator 12 through the through hole 24 of the housing 14, and the arranged rotor 20 is mounted on the stator 12. By mounting the rotor 20, the shaft 18 is arranged in the through holes 24 of the housing 14 that covers one end 12a side of the stator 12 and the housing 14 that covers the other end 12b side of the stator 12.

Next, the gap between the shaft 18 arranged in the through hole 24 and the housing 14 is sealed with the sealing member 30 (sealing step S6). As a result, it is possible to prevent water or oil from entering the space 32 of the housing 14.

In the present embodiment, a hole (communication hole 26) for promoting discharge of the impregnating agent 16 communicates the inner surface 14a with the through hole 24. Therefore, even if the hole (communication hole 26) is not closed, it is possible to prevent water or oil from entering the space 32 of the housing 14. Therefore, the step of closing the hole (communication hole 26) for promoting the discharge of the impregnating agent 16 can be omitted.

The configuration shown in FIG. 1 can be obtained by the above manufacturing method. In this embodiment, a housing 14 having a communication hole 26 for communicating the inner surface 14a and the through hole 24 is attached to the stator 12. As a result, the excess impregnating agent 16 remaining in the space 32 in the discharge step S3 can be satisfactorily discharged to the outside of the space 32. As a result, the possibility that debris of the cured impregnating agent 16 is generated inside the motor 10 is reduced, and the risk that the members such as the coil 22 provided inside the motor 10 are damaged by contact with the debris is also reduced.

In particular, when the communication hole 26 has an inclined portion 26SL that inclines from the opening 26OP on the through hole 24 side toward the inner surface 14a of the housing 14 so as to move away from the through hole 24, the impregnating agent 16 Emission is promoted. As a result, the possibility that debris of the cured impregnant 16 is generated inside the motor 10 is further reduced, and the risk that the members such as the coil 22 provided inside the motor 10 are damaged by contact with the debris is minimized. It can be suppressed.

As described above, according to the above-mentioned manufacturing method, it is possible to manufacture the electric motor 10 in which the risk of defects due to the excess impregnating agent 16 is reduced.

[Modification example]
Although the embodiments have been described above as an example of the present invention, it goes without saying that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention.

FIG. 5 is a cross-sectional view of the electric motor 10 of the first modification. In the first modification, the communication hole 26 formed in the housing 14 does not have the inclined portion 26SL. That is, the communication hole 26 extends along the through hole 24 to a position separated from the inner surface 14a by a predetermined distance, and extends from the position to the through hole 24 in a direction substantially orthogonal to the through hole 24. As described above, the communication hole 26 does not have to have the inclined portion 26SL. As described above, it is preferable that the communication hole 26 has the inclined portion 26SL from the viewpoint of promoting the discharge of the excess impregnating agent 16 remaining in the space 32.

[Invention obtained from the embodiment]
The inventions that can be grasped from the above-described embodiments and modifications are described below.

<First invention>
The first invention is an electric motor (10).
A stator (12) provided with a coil (22) and a stator (12).
A rotor (20) surrounded by a stator (12) and to which a shaft (18) is attached,
A housing (14) having a through hole (24) attached to the stator (12) so as to cover the coil (22) and on which the shaft (18) is located.
The impregnating agent (16) impregnated in the coil (22) and
A sealing member (30) that seals the gap between the shaft (18) and the housing (14) arranged in the through hole (24), and
With
The housing (14) is formed with a communication hole (26) that communicates the inner surface (14a) of the housing (14) on the stator (12) side and the through hole (24).

This provides an electric motor (10) with reduced risk of defects due to the excess impregnating agent (16).

The housing (14) covers both ends of the stator (12) in the direction in which the shaft (18) extends, and the communication hole (26) and the sealing member (30) cover one end of the stator (12). It may be provided in (14). As a result, the strength of the housing (14) can be easily increased as compared with the case where the communication holes (26) and the sealing member (30) are provided in the respective housings (14) covering both ends of the stator (12), and the electric motor (10). ) Is easy to reduce the number of parts.

The opening (26OP) on the through hole (24) side in the communication hole (26) may be located closer to the stator (12) than the seal member (30). This prevents water and oil from entering the space (32) surrounded by the stator (12) and the housing (14) even if the opening (26OP) on the through hole (24) side is not closed. It is possible to reduce the number of parts of the electric motor (10).

The opening (26OP) on the through hole (24) side in the communication hole (26) may be closed by the sealing member (30). As a result, the seal member (30) can be shared to close the opening (26OP) on the through hole (24) side, and the number of parts of the electric motor (10) can be suppressed.

The communication hole (26) has an inclined portion (26SL) that inclines from the opening (26OP) on the through hole (24) side in the communication hole (26) toward the inner surface (14a) so as to move away from the shaft (18). You may have. As a result, when the water, oil, or excess impregnating agent (16) remaining in the space (32) surrounded by the stator (12) and the housing (14) is discharged from the communication hole (26), the discharge thereof is performed. Is prompted.

<Second invention>
The second invention is a method for manufacturing an electric motor (10).
A mounting step of mounting a housing (14) having a through hole (24) through which a rotor (20) to which a shaft (18) is mounted can be inserted into a stator (12) provided with a coil (22).
After the mounting step, a dipping step of immersing the stator (12) and the housing (14) in the impregnating agent (16), and
After the dipping step, the excess impregnating agent (16) in the stator (12) is applied to the inner surface (14a) of the housing (14) on the stator (12) side and the through hole (24) formed in the housing (14). ), And a discharge process for discharging from the communication hole (26) and the through hole (24).
After the discharge step, a curing step of curing the impregnating agent (16) impregnated in the coil (22) and a curing step of curing the impregnating agent (16).
After the curing step, the mounting step of mounting the rotor (20) to the stator (12) and the mounting step
After the mounting step, a sealing step of sealing the gap between the shaft (18) arranged in the through hole (24) and the housing (14) with the sealing member (30), and
including.

This provides a method for manufacturing the electric motor (10) in which the risk of defects due to the excess impregnating agent (16) is reduced.

In the mounting process, the housings (14) are mounted on both ends of the stator (12) in the direction in which the shaft (18) extends, and the communication holes (26) and the sealing member (30) cover one end side of the stator (12). It may be provided in the housing (14). As a result, the strength of the housing (14) can be easily increased as compared with the case where the communication holes (26) and the sealing member (30) are provided in the respective housings (14) covering both ends of the stator (12), and the electric motor (10). ) Is easy to reduce the number of parts.

The opening (26OP) on the through hole (24) side in the communication hole (26) may be located closer to the stator (12) than the seal member (30). This prevents water and oil from entering the space (32) surrounded by the stator (12) and the housing (14) even if the opening (26OP) on the through hole (24) side is not closed. Therefore, the manufacturing method can be simplified by omitting the step of closing the opening (26OP).

The opening (26OP) on the through hole (24) side in the communication hole (26) may be closed by the sealing member (30). As a result, the seal member (30) can be shared to close the opening (26OP) on the through hole (24) side, and the manufacturing method can be simplified.

The communication hole (26) has an inclined portion (26SL) that inclines from the opening (26OP) on the through hole (24) side in the communication hole (26) toward the inner surface (14a) so as to move away from the shaft (18). You may have. As a result, when the water, oil, or excess impregnating agent (16) remaining in the space (32) surrounded by the stator (12) and the housing (14) is discharged from the communication hole (26), the discharge thereof is performed. Is prompted.

10 ... Electric motor 12 ... Stator 12a ... One end 12b ... The other end 14 ... Housing 14a ... Inner surface 14b ... Outer surface 16 ... Impregnant 18 ... Shaft (rotating shaft) 22 ... Coil 24 ... Through hole 26 ... Communication hole 30 … Seal member

Claims (10)

A stator with a coil and
A rotor surrounded by the stator and to which a shaft is attached,
A housing that is attached to the stator so as to cover the coil and has a through hole in which the shaft is arranged.
The impregnating agent impregnated in the coil and
A sealing member that seals the gap between the shaft and the housing arranged in the through hole, and
With
An electric motor in which a communication hole for communicating the inner surface of the housing on the stator side and the through hole is formed in the housing. The electric motor according to claim 1.
The housing covers both ends of the stator in the direction in which the shaft extends.
An electric motor in which the communication hole and the seal member are provided in the housing that covers one end side of the stator. The electric motor according to claim 1 or 2.
An electric motor in which the opening on the through hole side of the communication hole is located on the stator side of the seal member. The electric motor according to claim 1 or 2.
An electric motor in which the opening on the through hole side of the communication hole is closed by the seal member. The electric motor according to any one of claims 1 to 4.
The communication hole is an electric motor having an inclined portion that inclines toward the inner surface from the opening on the through hole side in the communication hole so as to move away from the shaft. The mounting process of mounting a housing with a through hole through which a rotor with a shaft is mounted to a stator provided with a coil, and
After the mounting step, a dipping step of immersing the stator and the housing in an impregnating agent, and
After the dipping step, the excess impregnating agent in the stator is discharged from the communication hole and the through hole formed in the housing, which communicate with the inner surface of the housing on the stator side and the through hole. Discharge process and
After the discharge step, a curing step of curing the impregnating agent impregnated in the coil and a curing step of curing the impregnating agent.
After the curing step, a mounting step of mounting the rotor on the stator and a mounting step.
After the mounting step, a sealing step of sealing the gap between the shaft and the housing arranged in the through hole with a sealing member,
Manufacturing methods for electric motors, including. The method for manufacturing an electric motor according to claim 6.
In the mounting step, the housing is mounted on both ends of the stator in the direction in which the shaft extends.
A method for manufacturing an electric motor, wherein the communication hole and the seal member are provided in the housing that covers one end side of the stator. The method for manufacturing an electric motor according to claim 6 or 7.
A method for manufacturing an electric motor, wherein the opening on the through hole side of the communication hole is located on the stator side of the seal member. The method for manufacturing an electric motor according to claim 6 or 7.
A method for manufacturing an electric motor, wherein the opening on the through hole side in the communication hole is closed by the seal member. The method for manufacturing an electric motor according to any one of claims 6 to 9.
A method for manufacturing an electric motor, wherein the communication hole has an inclined portion that inclines from an opening on the through hole side of the communication hole toward the inner surface so as to move away from the shaft.

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