JPH04359653A - Cooling equipment for motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor cooling device.

0002

2. Description of the Related Art In general, motors are required to be cooled sufficiently because various problems occur due to the heat generated by the motors. The most significant of the above-mentioned problems are thermal deterioration of the insulation material of the coils in the stator, etc., leading to poor insulation, and burnout of the coils. A mechanical error may occur in the bearing due to expansion, and if a bearing has a built-in encoder for detecting the rotation angle, its durability may deteriorate.

[0003] When cooling a motor used as an actuator in a robot, an air cooling method is generally used in which heat is conducted through air and released to the outside. By the way, if heat can be efficiently removed from the stator coil, the motor can be used at a higher output, and in this respect, a liquid cooling system is preferable to an air cooling system. Conventionally, in such a liquid cooling system, a water jacket is formed in the motor housing, etc., and a cooling liquid is flowed into the water jacket to remove heat from the stator coil via the cooling liquid.

0004

[Problems to be Solved by the Invention] However, although this water jacket structure provides higher cooling performance than an air cooling system, thermal resistance that exists between the cooling fluid and the stator coil cannot be avoided, and the cooling performance It is difficult to raise the level of confidence without thinking.

The present invention has been made in view of the above points, and its purpose is to improve the cooling structure of the motor.
The objective is to be able to obtain higher cooling efficiency than not only air cooling systems but also liquid cooling systems with a water jacket structure, so that the motor can be used with high output performance.

[0006]

[Means for Solving the Problems] In order to achieve this object, in the invention of claim 1, the housing of the motor has a sealed structure, and a refrigerant is circulated between the inside of the housing and the cooling means provided outside the housing. The liquid refrigerant condensed by the cooling means is injected to at least the stator coil, and the stator coil is cooled by the heat of evaporation.

Specifically, in the present invention, a stator and a rotor are fitted in a hermetically sealed housing;
The rotor is attached to an output shaft extending airtightly outside the housing, and includes a spraying means for spraying liquid refrigerant onto at least the coil of the stator, and a cooling means disposed outside the housing for cooling the gas refrigerant and condensing it into liquid refrigerant. and a circulation means for supplying the liquid refrigerant of the cooling means to the spraying means, and circulating the refrigerant so as to suck the gas refrigerant in the housing and return it to the cooling means.

[0008]

[Operation] According to the invention of claim 1, liquid refrigerant is injected from the spraying means toward the coil of the stator within the sealed housing of the motor, and this liquid refrigerant is heated and evaporated by contact with the coil. The heat cools the coil. The gas refrigerant that has become vapor inside the housing is sucked by the circulation means and supplied to the cooling means outside the housing, where it is cooled and condensed to return to the original liquid refrigerant. This liquid refrigerant is supplied to the spraying means by the circulation means and injected toward the stator coil, and the same refrigerant cycle is repeated thereafter. By doing this, there is no thermal resistance between the cooling fluid and the stator coil in the water jacket structure, and the stator coil inside the housing is cooled by direct contact with the refrigerant, effectively controlling the temperature of the stator coil. Can be lowered.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

FIG. 1 shows a motor M according to a first embodiment of the present invention. The motor M has a cylindrical housing 1 that is hermetically sealed, and the housing 1 includes a first housing 2;
It consists of a third housing 7 and a second housing 4 located between both housings 2 and 7, the first and third housings 2 and 7 having a cylindrical shape with a bottom, and the second housing 4 having a circular shape. They are each formed in a shape. These housings 2
, 4, and 7 have the same outer diameter, and are integrally assembled with the openings of the first and third housings 2, 7 abutting against each other, with the second housing 4 interposed therebetween. Bearing holes 3 and 5 are formed in the center of the bottom of the first housing 2 and in the center of the second housing 4, respectively.
The other end of the output shaft 8 is in the bearing hole 5 with bearings 9 and 1, respectively.
It is rotatably supported via 0. The bearing 9 in the bearing hole 3 of the first housing 2 is located outside the housing 1 within the bearing hole 3, and a seal member 11 is fitted into the bearing hole 3 inside the housing 1.

A rotor 12 is rotatably fixed to the output shaft 8. On the other hand, a stator 14 having a coil 13 wound thereon is integrally attached to the inner peripheral portion of the first housing 2, and the rotor 12 is rotated by supplying electric power to the coil 13 of the stator 14.

The second housing 4 has a plurality of openings 6,
6,... are formed around the bearing hole 5, and these openings 6, 6
, . . . communicates between the inside of the first housing 2 and the inside of the third housing 7. The third housing 7 extends toward the opposite side of the output shaft 8 with respect to the first and second housings 2 and 4.

Furthermore, inside the portion of the housing 1 surrounded by the first and second housings 2 and 4, a plurality of spray nozzles 21, 21, . . . constituting a spraying means are provided. Each spray nozzle 21 injects liquid refrigerant, and is arranged so that the injection direction is directed toward both sides of the coil 13 of the stator 14, that is, so as to inject the liquid refrigerant toward both sides of the stator coil 13. .

Each of the spray nozzles 21 is connected to a downstream end of a refrigerant supply branch pipe 22a. After these branch pipes 22a, 22a, . This cooler 2
6 is a heat exchanger that exchanges heat between a primary heat exchanger tube 26a and a secondary heat exchanger tube 26b, and the refrigerant supply pipe 22 is connected to one end of the primary heat exchanger tube 26a. Cooling water flows through the secondary heat transfer tube 26b, and the gas refrigerant pumped by a pump 24, which will be described later, is cooled by heat exchange with the cooling water in the cooler 26 and condensed into liquid refrigerant.

Further, the third housing 7 has an open end at the upstream end of a refrigerant return pipe 23 that passes through the housing 7. This return pipe 23 extends outside the housing 1, and its downstream end is connected to the primary heat exchanger pipe 2 in the cooler 26.
6a. Further, a pump 24 is disposed in the middle of the refrigerant return pipe 23, and the pump 24, the refrigerant supply pipe 22, and the refrigerant return pipe 23 supply the liquid refrigerant of the cooler 26 to each spray nozzle 21, 21,
A circulation means 25 is configured that circulates the refrigerant so as to supply the refrigerant to the refrigerant, and to suck the gas refrigerant in the housing 1 and return it to the cooler 26.

To explain the operation of the above embodiment, the pump 2
4, the refrigerant is circulated between the housing 1 of the motor M and the cooler 26. That is, the gas refrigerant discharged from the pump 24 flows through the primary heat exchanger tube 26a of the cooler 26.
There, the refrigerant is cooled by heat exchange with the cooling water in the secondary heat exchanger tube 26b and condensed into a liquid refrigerant. This liquid refrigerant is supplied to each spray nozzle 21 in the housing 1 through the refrigerant supply pipe 22, and from each nozzle 21 to the stator 1.
It is injected toward the coil 13 of No. 4. Accordingly, the liquid refrigerant is heated and evaporated by contact with the coil 13, and conversely, the coil 13 is cooled by this heat of evaporation. Then, the gas refrigerant that has become vapor in the housing 1 moves into the third housing 7 through the openings 6, 6, . and is sucked into the pump 24. Thereafter, the same refrigerant cycle as above is repeated.

Therefore, in this embodiment, the refrigerant is circulated between the housing 1 of the motor M and the cooler 26, and the liquid refrigerant is injected to the stator coil 13 to cool the stator coil 13, so that the water jacket structure is There is no thermal resistance existing between the cooling fluid and the stator coil, and the stator coil 13 within the housing 1 is cooled by direct contact with the coolant. As a result, stator coil 13
The temperature of the motor M can be efficiently lowered and its cooling efficiency can be increased, and the output of the motor M can be increased and used.

FIG. 2 shows a second embodiment of the present invention, which is applied to an actuator for a robot R for working in a vacuum environment (the same parts as in FIG. (omitted). This robot R is used to perform various tasks in a vacuum space. In the figure, 30 is a vacuum chamber, which is partitioned by a partition wall 31 (side wall) into an upper vacuum side (inside the vacuum chamber 30) and a lower atmospheric side in the figure. 1 arm 32 is attached and fixed. This first arm 32 is formed into a hollow shape and constitutes a sealed housing for the first motor M1, and a stator 36 having an output shaft 33, a rotor 34, and a coil 35 is located in the tip of the first arm 32. They are arranged with axes in orthogonal directions. Above output shaft 3
3 is hollow, one end of which protrudes airtightly outside the first arm 32, and the proximal end of the second arm 37 is rotatably joined to this protruding end. This second arm 37 is also
Like the arm 32, it is hollow, and the second motor M2
It constitutes a sealed housing, the internal space of which communicates with the space within the first arm 32 through the output shaft 33. A stator 41 having an output shaft 38 , a rotor 39 , and a coil 40 is disposed within the tip of the second arm 37 with its axis perpendicular to the second arm 37 . One end of the output shaft 38 projects out of the second arm 37 in an airtight manner, and a hand (not shown) is rotatably joined to this projecting end. Then, by operating the first and second motors M1 and M2, the second arm 37 and the hand are driven in a direct drive manner, and the hand on the distal end side is moved to the target position.

Also in this embodiment, each motor M1
, M2, spray nozzles 21', 21', . The downstream end of the pipe 22 is connected. Further, as described, the space within the second arm 37 is the internal space of the first arm 32 and the first motor M1.
The first arm 3
The upstream end of the refrigerant return pipe 23 is open at the base end wall of the refrigerant return pipe 23 . The upstream end of the refrigerant supply pipe 22 and the refrigerant return pipe 2
3 are connected to each other by a cooler 26, and this cooler 26 is placed on the atmosphere side. The rest of the structure is the same as that of the first embodiment.

In this embodiment, the operation of the pump 24 causes the refrigerant to flow into the first and second arms 32, 37 (
It is circulated between the housing of each motor M1, M2) and the cooler 26. That is, the gas refrigerant discharged from the pump 24 is supplied to the cooler 26 and condensed into liquid refrigerant, and this liquid refrigerant passes through the refrigerant supply pipe 22 to each spray nozzle 21.
' from each nozzle 21' to each motor M1.
, M2 toward the stator coils 35, 40, and the coils 35, 40 are accordingly cooled. The gas refrigerant that has become vapor in each of the arms 32 and 37 is
First and second arms 32, 3 whose internal spaces communicate with each other
The refrigerant flows into the refrigerant return pipe 23 through the pump 2
After that, the same refrigerant cycle as above is repeated.

[0021] Therefore, this embodiment also provides the same effects as those of the first embodiment. In particular, the cooling efficiency is better than the normal cooling structure used in robots, so even small motors M1 and M2 can be used with large torque, making this actuator for robots suitable for use in high temperature and vacuum environments. is obtained. Furthermore, although the spaces within the first and second arms 32 and 37 communicate with each other,
Since it is hermetically sealed from the outside, it has the advantage that there is no risk of deteriorating the degree of vacuum on the vacuum side.

In each of the above embodiments, the refrigerant is supplied to the motor M (
Although the fuel is injected only to the stator coils 13 (M1, M2), it may also be injected to the surrounding areas.

It goes without saying that the present invention can also be applied to motors for uses other than actuators in the robot R for working in a vacuum environment.

[0024]

As explained above, according to the invention of claim 1, the motor housing has a sealed structure, and a spraying means for spraying liquid refrigerant toward the stator coil fitted inside the housing is provided. In addition, a cooling means is provided to cool the gas refrigerant and return it to liquid refrigerant, and by circulating the refrigerant between this cooling means and the inside of the housing, the stator coil of the motor can be cooled by directly contacting the refrigerant. Therefore, the temperature of the stator coil can be efficiently lowered, cooling efficiency can be increased, and the motor can be used at a high output.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a motor according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a robot for working in a vacuum environment according to a second embodiment of the present invention.

[Explanation of symbols]

M, M1, M2...Motor 1...Housing 2...First housing 4...Second housing 7...Third housing (extension part) 8...Output shaft 12...Rotor 13...Coil 14...Stator 19...Fins 21, 21'... Spray nozzle (spray means) 22...refrigerant supply pipe 23...refrigerant return pipe 24...pump 25...circulation means 26...cooler (cooling means) R...robot 32, 37...arm (housing) 33, 38...output shaft 34, 39... Rotor 35, 40... Coil 36, 41... Stator

Claims (1)

[Claims] 1. A stator and a rotor are fitted in a hermetically sealed housing, the rotor is attached to an output shaft that extends airtightly outside the housing, and a spraying means for spraying liquid refrigerant onto at least the coils of the stator. a cooling means disposed outside the housing that cools the gas refrigerant and condenses it into a liquid refrigerant; and a cooling means that supplies the liquid refrigerant of the cooling means to the spraying means and sucks the gas refrigerant inside the housing to the cooling means. A cooling device for a motor, characterized in that it is equipped with a circulation means for circulating a refrigerant so as to return the coolant.