WO2020110238A1

WO2020110238A1 - Electric motor

Info

Publication number: WO2020110238A1
Application number: PCT/JP2018/043830
Authority: WO
Inventors: 治之長谷川
Original assignee: 三菱電機株式会社
Priority date: 2018-11-28
Filing date: 2018-11-28
Publication date: 2020-06-04
Also published as: JPWO2020110238A1; JP6608098B1; KR102256362B1; CN113169628B; KR20210043716A; CN113169628A

Abstract

This electric motor (100) is equipped with a detector (9) for detecting a rotational position of a rotor (2) and is provided with: a metal second bracket (6) for joining a frame (4) to which a stator (2) is attached and a detector (9); a first detector cover (10) for forming, together with the second bracket (6), a space for housing the detector (9); and a heat dissipation means (second detector cover (11)) attached to the second bracket (6) and dissipating heat stored in the second bracket (6).

Description

Electric motor

The present invention relates to an electric motor that includes a detector that detects the rotational position of a rotor.

When a motor is controlled with high accuracy, a detector is used to detect the rotational position of the rotor. The detector is composed of electronic parts, optical parts, magnetic parts, etc., but these parts are vulnerable to heat. Therefore, the temperature of the detector needs to be lower than that of the stator portion, which is the heat source of the electric motor.

Therefore, in the conventional electric motor, by disposing a resin member having low thermal conductivity between the metal detector cover and the electric motor bracket, the heat conducted from the stator side to the detector side of the electric motor The rise in temperature of the detector part is suppressed (see Patent Document 1).

In the electric motor described in Patent Document 1, a resin member cuts off heat generated on the stator side of the electric motor to suppress heat transfer to the detector. Further, in the electric motor described in Patent Document 1, since the metal detector cover has good heat dissipation, when the temperature of the detector rises, heat can be dissipated from the metal cover and an excessive temperature rise of the detector can be suppressed. ..

Japanese Patent Laid-Open No. 2018-82553

The motor described in Patent Document 1 can suppress the heat generated on the stator side of the motor from being transferred to the detector provided on the anti-load side. On the other hand, since the heat generated on the stator side of the motor is not transmitted to the anti-load side, the amount of heat generated on the stator side of the motor is radiated from the anti-load side, and the heat dissipation performance of the entire motor decreases To do. When the heat dissipation is lowered, there is a problem that the output of the electric motor needs to be reduced in order to suppress the heat generation amount of the electric motor. In addition, since the amount of heat transferred to the anti-load side is suppressed, there is a problem that the cooling efficiency is lowered when the electric motor is cooled by applying cold air to the anti-load side such as the cover portion of the detector.

The present invention has been made in view of the above, and an object of the present invention is to obtain an electric motor that can suppress both a rise in temperature of a detector and a decrease in heat radiation performance of the electric motor as a whole.

In order to solve the above-mentioned problems and to achieve the object, the present invention is an electric motor including a detector that detects a rotational position of a rotor, in which a frame to which a stator is attached and a detector are joined. A metal bracket, a first detector cover that forms a space for accommodating a detector together with the bracket, and a heat radiating unit that is attached to the bracket and radiates heat accumulated in the bracket are provided.

The electric motor according to the present invention has the effect of suppressing the temperature rise of the detector and suppressing the decrease of the heat dissipation performance of the electric motor as a whole.

The figure which shows the structural example of the electric motor concerning Embodiment 1. The figure which shows the modification of the electric motor concerning Embodiment 1. The figure which shows the structural example of the electric motor concerning Embodiment 2. The figure which shows the structural example of the electric motor concerning Embodiment 3.

The electric motor according to the embodiment of the present invention will be described below in detail with reference to the drawings. The present invention is not limited to this embodiment.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of an electric motor 100 according to the first exemplary embodiment of the present invention. FIG. 1 shows a cross section of the electric motor 100.

The electric motor 100 includes a shaft 1, a rotor 2, a stator 3, a frame 4, a first bracket 5, a second bracket 6, a first bearing 7, and a second bearing 8. The detector 9, a first detector cover 10, and a second detector cover 11 are provided. The detector 9 includes a printed circuit board 91 on which a detection circuit for detecting the rotational position of the rotor 2 is formed, a rotating plate 92, and a housing 93. A load (not shown) is connected to the load side of the electric motor 100 via the shaft 1. The opposite side of the load side is the anti-load side. The detector 9 is provided on the non-load side of the electric motor 100. That is, the detector 9 is attached to the anti-load side of the electric motor 100 by being joined to the frame 4 by the second bracket 6.

The shaft 1 is connected to the rotor 2 and can rotate around the axis A together with the rotor 2. The rotor 2 has a cylindrical shape, and a permanent magnet is provided on the curved surface facing the stator 3. The stator 3 is composed of a coil and an iron core, and has a cylindrical space that houses the rotor 2. When an electric current flows through the coil, the stator 3 generates a magnetic force to rotate the rotor 2. The stator 3 is attached to the frame 4. The first bracket 5 is provided on the load side of the electric motor 100, and the second bracket 6 is provided on the anti-load side of the electric motor 100. A first bearing 7 is installed on the side of the first bracket 5 facing the rotor 2, and a second bearing 8 is installed on the side of the second bracket 6 facing the rotor 2. There is. The first bearing 7 and the second bearing 8 rotatably support the shaft 1. The frame 4 is a metal frame. The first bracket 5 and the second bracket 6 are metal brackets.

The rotary plate 92 of the detector 9 is attached to the anti-load side of the shaft 1 while being housed in the metal housing 93, and rotates together with the shaft 1 and the rotor 2. The rotating plate 92 is provided with a slit, and the light passing through the slit is detected by a detection circuit formed on the surface of the printed board 91 facing the rotating plate 92, whereby the rotational position of the rotor 2 is specified. To be done. The printed circuit board 91 is attached to the counter load side of the housing 93, and forms a housing space for the rotary plate 92 together with the housing 93.

The first detector cover 10 is a resin cover and is attached to the second bracket 6. The first detector cover 10 surrounds the detector 9 together with the second bracket 6. The second detector cover 11 is a metal cover and covers the first detector cover 10. The second detector cover 11 is attached to the second bracket 6 with its inner surface in close contact with the first detector cover 10. In this way, the first detector cover 10 and the second detector cover 11 form the cover of the detector 9. The first detector cover 10 and the second detector cover 11 are attached to the second bracket 6 to form a space in which the detector 9 is housed. The thermal conductivity of the second detector cover 11 is higher than that of the first detector cover 10. In FIG. 1, the second detector cover 11 is configured to cover a part of the first detector cover 10, but the second detector cover 11 is configured to cover the entire first detector cover 10. Good.

As shown in FIG. 1, the electric motor 100 has a metal second detector cover 11 arranged on the outside and a resin first detector cover 10 arranged on the inside. Therefore, the heat generated in the stator 3 is hard to be transferred to the detector 9, while the heat is efficiently transferred to the external second metal detector cover 11. That is, the heat generated by the stator 3 is transmitted to the second detector cover 11 via the frame 4 and the second bracket 6. As a result, the second detector cover 11 that is in contact with the outside air can radiate heat to the outside air and improve the heat dissipation of the entire electric motor 100. Here, the second detector cover 11 constitutes a heat radiating means for radiating the heat accumulated in the second bracket 6. Further, the electric motor 100 is provided with a cooling fan on the anti-load side, and when cool air from the fan is applied to the electric motor 100, heat is radiated from the second detector cover 11 efficiently and the electric motor 100 is cooled efficiently. It becomes possible to do.

Further, by forming the second detector cover 11 with a metal of a ferromagnetic material, it is possible to suppress the transmission of electromagnetic waves and magnetic flux from the outside to the detection circuit of the detector 9, and to obtain the effect of suppressing malfunction of the detector 9. .. Further, it is possible to prevent the electromagnetic wave and the magnetic flux generated inside the detector 9 from leaking to the outside. Since the second detector cover 11 is exposed to the outside air, it can be made resistant to corrosion by plating it to prevent corrosion or by using stainless steel (SUS: Steel Use Stainless). .. Further, since the second detector cover 11 is provided with the first detector cover 10 made of resin inside, it is not necessary to provide a seal structure for preventing foreign matter from entering the inside of the detector 9. Absent. Therefore, the accuracy of the shape of the second detector cover 11 and the processing accuracy when manufacturing the second detector cover 11 can be simplified, and the second detector can be manufactured by a relatively inexpensive method such as pressing. The cover 11 can be manufactured. Further, even when the second detector cover 11 is manufactured by a method such as die casting and casting, it is not necessary to obtain accuracy by machining, and it is possible to attach a fin to the outside of the second detector cover 11. It is also possible to manufacture the second detector cover 11 and the first detector cover 10 by integral molding, reduce the number of parts, and reduce the number of assembly steps.

Also, it is necessary to arrange a connector for the detector on the cover of the detector 9. Therefore, it is not necessary to completely cover the first detector cover 10 with the second detector cover 11 to completely duplicate the first detector cover 10. The surface area of the second detector cover 11 may be designed according to the heat radiation required for the electric motor 100 to operate normally, and it is not necessary to duplicate the portion where the connector is arranged. When the detector 9 generates a large amount of heat, the heat of the detector 9 is released to the connector side, or a metal member is attached to the first detector cover 10 separately from the second detector cover 11, The heat of the detector 9 may be released from there. In this way, the thickness and shape of the second detector cover 11 are freely designed according to the required heat dissipation and function.

Furthermore, the configuration shown in FIG. 2 may be used. FIG. 2 is a diagram illustrating a modified example of the electric motor according to the first embodiment.

The electric motor 101 shown in FIG. 2 has a configuration in which a plate 12 which is a resin plate is inserted between the second bracket 6 of the electric motor 100 shown in FIG. 1 and the detector 9 and the first detector cover 10. Electric motor. The plate 12 is provided to suppress the amount of heat transferred from the second bracket 6 to the detector 9. That is, in the electric motor 101, the metal second bracket 6 and the detector 9 are separated by the plate 12 having low heat conductivity, and the heat transmitted from the second bracket 6 to the detector 9 is further suppressed. You can The same effect can be obtained by forming the housing 93 supporting the printed circuit board 91 of the detector 9 from resin instead of adding the plate 12. The plate 12 may be added and the housing 93 may be made of resin. Further, instead of the plate 12, the surface of the second bracket 6 in contact with the detector 9 and the first detector cover 10 may be heat-insulated to make it difficult for heat to be transmitted to the detector 9. Even when the second bracket 6 is heat-insulated, the second detector cover 11 is fixed to the second bracket 6 with a metal screw, or the second detector cover 11 of the second bracket 6 contacts. It is possible to facilitate the transfer of heat from the second bracket 6 to the second detector cover 11 by machining the part to be subjected to machining to remove the heat insulating coating. Further, instead of the plate 12, the housing 93 of the detector 9 may be heat-insulated to make it difficult for heat to be transferred to the inside of the detector 9.

As described above, in the

electric motors

100 and 101 according to the present embodiment, the cover of the detector 9 includes the first detector cover 10 on the inner side close to the detector 9 and the second detector cover 11 on the outer side. The first detector cover 10 is made of resin, and the second detector cover 11 is made of metal. Further, the second detector cover 11 is in contact with the second bracket 6 made of metal. Further, the electric motor 101 includes a plate 12 between the second bracket 6 and the detector 9. According to the

electric motors

100 and 101 according to the present embodiment, it is possible to suppress an increase in the temperature of the detector 9 and suppress deterioration of the heat dissipation performance of the electric motor as a whole. The electric motor 101 can further suppress the temperature rise of the detector 9 as compared with the electric motor 100.

Embodiment 2.
FIG. 3 is a diagram illustrating a configuration example of the electric motor according to the second embodiment. In FIG. 3, the same components as those of the electric motor 100 according to the first embodiment shown in FIG. 1 are designated by the same reference numerals. In the present embodiment, description of parts common to those of the electric motor 100 according to the first embodiment will be omitted.

The electric motor 102 according to the present embodiment has an air layer 13 between the first detector cover 10 and the second detector cover 11. That is, in the electric motor 100 according to the first embodiment, the first detector cover 10 and the second detector cover 11 are attached to the second bracket 6 in a state of being in close contact with each other to form the cover of the detector 9. Was there. On the other hand, in the electric motor 102, the cover of the detector 9 is formed by attaching the electric motor 102 to the second bracket 6 in a state where there is a gap between the first detector cover 10 and the second detector cover 11. is doing. Thus, in the electric motor 102, between the first detector cover 10 made of resin, the second detector cover 11 made of metal, and the first detector cover 10 and the second detector cover 11, The cover of the detector 9 is formed by the air layer 13 provided in the. In the electric motor 102, the air layer 13 plays a role of heat insulation by providing the gap, that is, the air layer 13 between the first detector cover 10 and the second detector cover 11, and the second detector cover is provided. The heat transfer from 11 to the first detector cover 10 is interrupted. As a result, the amount of heat transferred from the second detector cover 11 to the detector 9 is reduced. Further, the amount of heat released from the second detector cover 11 to the atmosphere is increased, and the heat dissipation of the entire electric motor 102 is improved.

By providing the air layer 13 between the first detector cover 10 and the second detector cover 11, it is possible to make it difficult for the heat of the second detector cover 11 to be transferred to the first detector cover 10 side. Is possible. In addition, by providing the air layer 13, it is possible to allow cool air or cooling water to flow through the air layer 13 to efficiently cool the electric motor 102. Further, by sealing the space between the first detector cover 10 and the second detector cover 11 and then lowering the pressure of the air layer 13, the heat from the second detector cover 11 to the detector 9 side is reduced. It is possible to further reduce the conductivity. The first detector cover 10 and the second detector cover 11 may be partially brought into contact with each other to keep the gap (thickness of the air layer 13) constant or to have strength.

As described above, the electric motor 102 according to the second embodiment has the air layer 13 as a gap between the first detector cover 10 and the second detector cover 11, and thus the electric motor according to the first embodiment. Compared with 100, the amount of heat conducted inside the detector 9 can be reduced, and the amount of heat radiated from the second detector cover 11 can be increased.

Note that, like the electric motor 101 shown in FIG. 2, the electric motor 102 has a configuration in which a plate is inserted between the second bracket 6 and the detector 9, and the amount of heat transferred from the second bracket 6 to the detector 9 is You may make it suppress.

Embodiment 3.
FIG. 4 is a diagram illustrating a configuration example of the electric motor according to the third embodiment. 4, the same components as those of the electric motor 102 according to the second embodiment shown in FIG. 3 are denoted by the same reference numerals as those in FIG. In the present embodiment, description of parts common to those of the electric motor 102 according to the second embodiment will be omitted.

As shown in FIG. 4, the electric motor 103 according to the present exemplary embodiment is similar to the electric motor 102 according to the second exemplary embodiment in that the air between the first detector cover 10 and the second detector cover 11 is reduced. It has a layer 13. Further, in the electric motor 103, the first detector cover 10 and the second detector cover 11 are attached to the second bracket 6 by the metal screws 14.

As described above, in the electric motor 103 according to the third embodiment, the second detector cover 11 and the first detector cover 10 are fixed to the second bracket 6 by co-tightening with the metal screw 14. There is. In the electric motor 103, the screw 14 for fixing the second detector cover 11 and the first detector cover 10 to the second bracket 6 is shared, so that the number of parts can be reduced and the man-hours for assembling the electric motor 103 can be reduced. Can be reduced. Further, in the electric motor 103, since the screw 14 used for joint tightening is made of metal, heat is easily transferred from the second bracket 6 to the second detector cover 11 via the screw 14, and the second bracket 6 The amount of heat transferred from the second detector cover 11 made of metal can be increased.

The location where the second detector cover 11 and the first detector cover 10 are fastened together with the screws 14 is not limited to the second bracket 6 shown in FIG. It may be a metal part of the body. Even when the location where the second detector cover 11 and the first detector cover 10 are fastened together with the screws 14 is the metal portion of the above-mentioned housing, the same as when fastening together with the second bracket 6. The effect can be obtained.

It should be noted that, similarly to the electric motor 101 shown in FIG. 2, the electric motor 103 has a configuration in which a resin plate similar to the plate 12 of the electric motor 101 is inserted between the second bracket 6 and the detector 9. The amount of heat transferred from the bracket 6 to the detector 9 may be suppressed.

The configurations described in the above embodiments are examples of the content of the present invention, and can be combined with another known technique, and the configurations of the configurations are not departing from the scope of the present invention. It is also possible to omit or change parts.

1 shaft, 2 rotor, 3 stator, 4 frame, 5 first bracket, 6 2nd bracket, 7 1st bearing, 8 2nd bearing, 9 detector, 10 1st detector cover, 11 second detector cover, 12 plate, 13 air layer, 14 screw, 91 printed circuit board, 92 rotating plate, 93 housing, 100, 101, 102, 103 electric motor.

Claims

An electric motor having a detector for detecting the rotational position of a rotor,
A bracket made of metal that joins the frame to which the stator is attached and the detector,
A first detector cover forming a space for accommodating the detector together with the bracket;
A heat radiating means attached to the bracket to radiate heat accumulated in the bracket,
An electric motor comprising:
The heat dissipation means is a second detector cover attached to the bracket and covering a part or all of the first detector cover,
The thermal conductivity of the second detector cover is higher than the thermal conductivity of the first detector cover,
The electric motor according to claim 1, wherein:
The electric motor according to claim 2, wherein the first detector cover is a resin cover and the second detector cover is a metal cover.
The electric motor according to claim 3, wherein the second detector cover is fixed to the bracket with a metal screw.
The electric motor according to claim 4, wherein the first detector cover and the second detector cover are fixed to the bracket by co-tightening with a metal screw.
The electric motor according to any one of claims 2 to 5, wherein a gap is provided between the first detector cover and the second detector cover.
7. A plate made of resin is provided between the bracket and the detector, and the bracket and the detector are separated by the plate, according to any one of claims 1 to 6. Electric motor.