JP2003199291A - Cooling apparatus for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost cooling apparatus for a motor, capable of improving cooling efficiency with no increase in the flow rate of a refrigerant, and also capable of reducing the man-hour for machining of members forming a refrigerant groove, with no effect of circularity of a frame, with less assembling processes. <P>SOLUTION: The cooling apparatus for a motor comprises a stator iron-core 3 comprising a laminated iron-core with an equipped stator coil 4, and a frame so provided as to contact the outer peripheral surface of the stator iron-core 3, and cools the stator by making the refrigerant flow in the frame. The frame comprises a first frame 10 provided on the outer peripheral surface of the stator iron-core 3 and a second frame 11 so provided as to contact the outer peripheral surface of the first frame 10. On the surface of the first frame 10 that contacts the second frame 11, a refrigerant groove 5 is provided which comprises a minute annular gap, extending circumferentially. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an electric motor used, for example, for driving a machine tool spindle, and more particularly to a device for cooling a stator with a refrigerant liquid.

[0002]

2. Description of the Related Art Conventionally, a cooling device for an electric motor, which is used for driving a spindle of a machine tool and cools a stator with a coolant, is shown in FIG. FIG. 5 is a side sectional view of an electric motor showing a conventional technique. In the figure, 21 is a rotating shaft, 22 is a rotor, 23 is a stator core, 24 is a frame, 25 is a mold resin, 26 is a stator coil, 27 is an inlet, 28 is an outlet, 29 is a refrigerant liquid groove, 30 is a rotation stop screw. A stator core 23, which is a laminated core, is provided facing the outer periphery of a rotor 22 fixed to the rotating shaft 21. The stator core 23 includes a stator coil 26, and the frame 24 is fitted to the outer periphery of the stator core 23 via a resin film. On the surface of the inner periphery of the frame 24 that contacts the outer periphery of the stator core 23, multiple spiral coolant grooves 29 are provided, and the coolant inlets 27 and An outlet 28 is provided and opens at the outer periphery of the frame 24. Further, a mold resin 25 is filled between the inner circumference of the frame 24, the end surface of the stator core 23, and the coil end of the stator coil 26 to easily transfer the heat generated by the stator coil 26 to the frame 24. I am doing it. Then, between the stator core 23 and the frame 24, the rotation-preventing screw 30 is attached to the stator core 2 from the frame 24.
It is screwed in toward 3, and is adapted to transmit the torque applied between the stator core 23 and the frame 24 (see, for example, Patent Document 1).

[0003]

[Patent Document 1] Japanese Utility Model Publication No. 7-47973 (FIG. 1)

[0004]

By the way, in the means for cooling the stator by flowing the refrigerant liquid through the refrigerant liquid groove 29 provided in the frame 24 as in the prior art, in order to further improve the cooling efficiency, the cooling is generally performed. When the refrigerant is in contact with the stator by increasing the flow rate of the refrigerant liquid by increasing the capacity of the pump of the unit (not shown) or increasing the number of spiral refrigerant liquid grooves 29, the refrigerant that contributes to heat transfer The contact area is increased. However, the former means for increasing the pump capacity of the cooling unit has a problem in that the cost of the cooling unit itself increases due to an increase in the capacity of the pump electric motor and the power consumption during operation increases. there were. On the other hand, the latter means for increasing the number of the spiral refrigerant liquid grooves 29 increases the cost of machining the member for forming the refrigerant liquid grooves 29, which causes a cost increase, which results in cost reduction in recent years and energy saving. There was a problem that it was difficult to meet the request.

Further, in the prior art, since the turning locating screw 30 has to be tightened in the radial direction from the outer periphery of the frame 24 toward the stator core 23, if the fastening force of the anti-rotation screw 30 in the radial direction becomes too strong. The brackets 31 and 32 provided on the load side and the non-load side of the frame 24 while deteriorating the roundness of the frame 24.
Distortion occurs in the mating surface with and the distortion is caused by the bracket 31,
There is a problem that the bearings 33 and 34 fall through the shaft 32 and cause vibration of the electric motor. Then, in the above fastening method, the frame 24 is changed while changing the posture of the electric motor.
Because of the method of fastening from the radial direction on the entire circumference of
Since a larger electric motor requires a large-scale work using a crane, there is a problem that the number of assembling steps increases and the cost increases.

The present invention has been made to solve the above-mentioned problems, and it is possible to improve the cooling efficiency without increasing the flow rate of the refrigerant liquid, and to reduce the number of man-hours for machining the member forming the refrigerant liquid groove. It is an object of the present invention to provide an inexpensive electric motor cooling device that is capable of achieving the above, and that has a small roundness of the frame without being affected by the roundness of the frame.

[0007]

In order to solve the above-mentioned problems, the present invention according to claim 1 provides a stator core comprising a laminated core provided with a stator coil and an outer peripheral surface of the stator core. And a first frame provided on the outer peripheral surface of the stator core, and a first frame provided on the outer peripheral surface of the stator core. A second frame provided in contact with the outer peripheral surface of one frame;
The frame and the refrigerant liquid groove in which a minute annular gap is formed so as to extend in the circumferential direction are provided on the surface in contact with either one of the second frame and the other. According to a second aspect of the present invention, in the cooling device for the electric motor according to the first aspect, a cross-sectional area viewed from an inflow direction of an inflow port serving as an inlet portion of the refrigerant liquid groove is A, and a cross-sectional area viewed from an axial direction of the refrigerant liquid groove. When the sectional area is B, the relationship of A ≧ B is satisfied. According to a third aspect of the present invention, in the cooling device for an electric motor according to the first or second aspect, the refrigerant liquid groove is provided with a tapered portion at least in the vicinity of an inlet of the refrigerant liquid. According to a fourth aspect of the present invention, in the cooling device for the electric motor according to the first or second aspect, a stepped portion is formed at one end of the second frame in the axial direction, and the end portion of the first frame and the first frame are formed. The stepped portions of the two frames are fixed in the thrust direction by fastening screws. According to a fifth aspect of the present invention, in the electric motor cooling device according to the fourth aspect, the first frame and the second frame are fastened in a space in which the stator coil is housed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of an electric motor showing a first embodiment of the present invention, FIG. 2 shows a configuration of a frame, a refrigerant liquid groove and an inflow port, (a) of FIG. The right sectional view which follows the line, (b) is the sectional view which looked at the inflow mouth of (a) from the Y direction. In the figure, 1 is a rotary shaft, 2 is a rotor, 3 is a stator core, 4 is a stator coil, 5 is a refrigerant liquid groove, 6 is an inlet, 7 is a supply pipe, 8 is an outlet, and 9 is a recovery. Piping, 10 is the first frame, 10A is a female screw portion,
11 is a second frame, 11A is a through hole, 11B is a stepped portion, 12 is a cooling unit, 13 is a fastening screw, 14 and 15
Are brackets, and 16 and 17 are bearings. The configuration in which the stator core 3 having the stator coil 4 is provided on the outer circumference of the rotor 2 fixed to the rotary shaft 1 is the same as the conventional technique.

The features of the present invention are as follows. That is, as a component corresponding to the frame of the prior art,
The first frame 10 provided on the outer peripheral surface of the stator core 3
And a second frame 11 provided in contact with the outer peripheral surface of the first frame 10 is used.
The surface of the first frame 10 that contacts the second frame 11 is provided with a refrigerant liquid groove 5 having a minute annular gap that extends in the circumferential direction, and is processed into a smooth concentric cylindrical shape. Further, a coolant liquid inlet 6 and a coolant liquid outlet 8 are provided at both ends of the coolant liquid groove 5, and are opened to the outer periphery of the second frame 11. O-rings (not shown) are provided between the first frame 10 and the second frame 11 at both ends of the refrigerant liquid groove 5 to seal the refrigerant liquid so as not to leak. Further, as shown in FIG. 2, when the cross-sectional area viewed from the inflow direction of the inflow port 6 serving as the inlet portion of the refrigerant liquid groove 5 is A and the cross-sectional area viewed from the axial direction of the refrigerant liquid groove 5 is B, A ≧ B
Have a relationship of. Then, as shown in FIG. 1, a female screw portion 10A is provided on the end portion of the first frame 10,
A stepped portion 11B having a through hole 11A is formed at one end of the frame 11 in the axial direction, and the stepped portion 11B of the second frame 11 is passed through the female screw portion 10A at the end of the first frame 10. It is fixed by being screwed in the thrust direction with the fastening screw 13 through the hole 11A. The first frame 10 and the second frame 11 are fastened in a space S in which the stator coil 4 is housed.

In such a structure, the heat generated by the loss such as the copper loss or the iron loss generated in the stator coil 4 and the stator core 3 when the electric motor is operated is from the first frame 10 to the second frame. Although it conducts heat to 11, the refrigerant liquid supplied from the cooling unit 12 through the supply pipe 7 is fixed when passing through the refrigerant liquid groove 5 provided between the first frame 10 and the second frame 11. The heat generated in the child coil 4 and the stator core 3 is taken away, and the heat is exchanged from the refrigerant liquid groove 5 to the cooling unit 12 through the recovery pipe 9 and the above operation is repeated.

FIG. 3 is a diagram showing a comparison of the cooling effects of the present invention and the prior art. That is, the ratio of the motor loss to the armature coil temperature rise is compared in percentage. According to this, according to the present invention, the cooling effect of the present invention is about 2 times lower than the conventional one.
It is possible to increase by 0%.

Since the first embodiment of the present invention has the above-mentioned structure, since the refrigerant liquid groove 5 is processed into a smooth concentric cylindrical shape, it is processed into a complicated multi-thread spiral groove as in the conventional case. Compared to the above, it is possible to provide a cooling device for an electric motor, which is easy to process and can reduce the number of machining steps of a member that forms a flow path of a refrigerant liquid, and which enables cost reduction.

Further, since the refrigerant liquid groove 5 has a minute annular gap formed between the first frame 10 and the second frame 11, the capacity of the pump of the cooling unit is increased and the flow rate of the refrigerant liquid is increased. It is possible to increase the flow velocity of the refrigerant liquid without increasing the heat transfer efficiency between the first frame 10, the refrigerant liquid groove 5 and the second frame 11, thereby increasing the cooling efficiency.

Further, since the cross-sectional area A of the refrigerant liquid groove as viewed from the inflow direction of the inlet 6 is made larger than the cross-sectional area B of the refrigerant liquid groove 5 as viewed in the axial direction, the number of machining steps is reduced, The cost can be reduced.

The present embodiment can solve the problems that the cost of the cooling unit itself increases and the power consumption during operation increases.

Then, in this embodiment, a stepped portion 11B is formed at one axial end of the second frame 11, and the end portion of the first frame 10 and the stepped portion 11B of the second frame 11 are directed in the thrust direction. Since the fastening screw 13 fixes the fastening force of the fastening screw 13 mainly in the thrust direction, the first frame 10 and the second frame 11 are fastened.
The effect on the roundness of can be reduced. As a result, the fitting between the load-side and anti-load-side brackets 14 and 15 and the second frame 11 becomes smooth, the assembly becomes easy, and the vibration due to the tilting of the bearings 16 and 17 does not occur. Further, in the fastening method according to the present embodiment, the fastening is performed by the fastening screw 13 in the thrust direction of the second frame 11 to the first frame 10, so that the work can be performed without changing the posture with the electric motor left. You can
The number of assembly steps can be reduced and the cost can be suppressed. Furthermore, since the first frame 10 and the second frame 11 are fastened in the space S in which the stator coil 4 is housed, water or the like intrudes into the electric motor from the outside via the fastening screw 13. It can prevent problems and improve environmental resistance.

FIG. 4 is an enlarged side sectional view of a frame portion showing a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the refrigerant liquid groove 5 has tapered portions 6A and 8A for reducing the flow velocity of the refrigerant liquid in the vicinity of the refrigerant liquid inlet 6 and the refrigerant liquid outlet 8. That is the point.

In such a structure, the refrigerant liquid flowing from the inflow port 6 first flows around the entire circumference of the refrigerant liquid groove 5 at the axial position of the inflow port 6 before passing through the tapered part 6A, and then the tapered portion. Pass 6A. Since the refrigerant liquid flows in uniformly from the refrigerant liquid groove 5 in the axial direction on the outlet 8 side over the entire circumference thereof, the refrigerant liquid can flow in a predetermined direction in the circumferential direction of the stator core 3 and the stator coil 4. These can be cooled uniformly without being biased.

Since the second embodiment of the present invention has the above-mentioned structure, the flow velocity in the refrigerant liquid groove 5 is increased by providing the tapered portions 6A and 8A, so that the refrigerant liquid groove 5 is larger than that in the first embodiment. The heat transfer performance inside can be improved. Further, in the coolant liquid groove 5 located on the outer periphery of the stator coil 4 in the stator core 3, the coolant liquid evenly flows into the entire periphery thereof, so that the temperature rise of the stator core 3 and the stator coil 4, etc. Can be equalized in the circumferential direction, the cooling efficiency can be improved, and thermal deformation due to uneven thermal expansion can be prevented. For example, the electric motor according to the present invention is a machine tool spindle built-in type (built-in type electric motor).
When it is used for driving, it is possible to prevent the deformation due to uneven thermal expansion from adversely affecting the dimensional change and accuracy of the main shaft member. In addition, by using the coolant liquid inlet on the mounting side to the machine tool, the mounting side to the machine tool is cooled more effectively, preventing heat transfer from the electric motor to the machine tool and at the same time changing the dimensions of the members due to thermal expansion. Alternatively, the problem that the processing accuracy is adversely affected does not occur. In the present embodiment, the second frame of the first frame 10 is
Although the refrigerant liquid groove 5 having a minute annular gap formed so as to extend in the circumferential direction is provided on the surface contacting the frame 11, conversely,
The coolant liquid groove 5 may be provided on the surface of the second frame 11 that contacts the first frame 10.

[0020]

As described above, the present invention has the following effects. Since the first embodiment of the present invention has the above-described configuration, the refrigerant liquid groove is processed into a smooth concentric cylindrical shape, and therefore, compared with the conventional one processed into a complicated multi-row spiral groove. It is possible to provide a cooling device for an electric motor, which can easily reduce the number of man-hours for machining a member that forms a flow path of the refrigerant liquid, and can reduce the cost.

Further, the coolant liquid grooves are formed in the first frame and the second frame.
Since there is a minute annular gap formed between the frames, the flow rate of the refrigerant liquid can be increased without increasing the capacity of the cooling unit pump to increase the flow rate of the refrigerant liquid, and the first frame, The heat transfer between the coolant liquid groove and the second frame can be improved, and the cooling efficiency can be improved. Further, since the cross-sectional area of the refrigerant liquid groove as viewed from the inflow direction of the refrigerant liquid groove is made larger than the cross-sectional area of the refrigerant liquid groove as viewed in the axial direction, the number of machining steps can be reduced and the cost can be reduced. Then, it is possible to solve the problem that the cost of the cooling unit itself increases and the power consumption during operation increases.

In this embodiment, a stepped portion is formed at one end of the second frame in the axial direction, and the end portion of the first frame and the stepped portion of the second frame are fastened by a fastening screw in the thrust direction. Since the fixing is performed, the fastening force of the fastening screw is mainly applied in the thrust direction, so that the influence on the circularity of the first frame and the second frame can be reduced. As a result, the fitting between the load-side and anti-load-side brackets and the frame becomes smooth, assembly becomes easy, and vibration due to the tilting of the bearing does not occur. Also,
In the fastening method according to the present embodiment, fastening is performed from the second frame in the thrust direction of the first frame with fastening screws. Therefore, it is possible to perform work without changing the posture while leaving the electric motor, and the number of assembly steps is reduced. It can be reduced and the cost can be suppressed.

Furthermore, since the first frame and the second frame are fastened in the space in which the stator coil is housed, the problem of water invading from the outside into the electric motor through the fastening screw is prevented. The environment resistance can be improved.

Since the second embodiment of the present invention has the above-mentioned structure, the taper portion increases the flow velocity in the refrigerant liquid groove, and the heat transfer performance in the refrigerant liquid groove is improved as compared with the first embodiment. Can be improved. Further, in the coolant liquid groove located on the outer circumference of the stator coil in the stator core, the coolant liquid flows evenly over the entire circumference, so that the temperature rise of the stator core and the stator coil, etc. in the circumferential direction. It becomes equal and cooling efficiency can be improved, and thermal deformation due to uneven thermal expansion can be prevented. For example, when the electric motor according to the present invention is used for driving a machine tool spindle built-in type, it is possible to prevent the deformation caused by uneven thermal expansion from adversely affecting the dimensional change and accuracy of the spindle member.

Further, by making the inlet side of the coolant liquid on the mounting side to the machine tool, the mounting side to the machine tool is further cooled, the heat transfer from the electric motor to the machine tool is prevented, and at the same time, the member due to thermal expansion. The problem that the dimensional change or the processing accuracy is adversely affected does not occur.

[Brief description of drawings]

FIG. 1 is a side sectional view of an electric motor showing a first embodiment of the present invention.

2A and 2B are views showing a configuration of a frame, a refrigerant liquid groove, and an inlet, where FIG. 2A is a sectional view taken along line XX of FIG. 1, and FIG. 2B is an inlet of FIG. It is sectional drawing which looked at from the Y direction.

FIG. 3 is a diagram showing a comparison of cooling effects of the present invention and the prior art.

FIG. 4 is an enlarged side sectional view of a frame portion showing a second embodiment of the present invention.

FIG. 5 is a side sectional view of an electric motor showing a conventional technique.

[Explanation of symbols]

1 rotation axis 2 rotor 3 Stator core 4 Stator coil 5 Refrigerant liquid groove 6 Inlet 6A taper part 7 Supply piping 8 Outlet 8A taper part 9 Recovery piping 10 First frame 10A female thread 11 second frame 11A through hole 11B stepped section, 12 Cooling unit 13 Fastening screw 14, 15 bracket 16, 17 bearing

Claims (5)

[Claims] 1. A stator core comprising a laminated core provided with a stator coil, and a frame provided in contact with an outer peripheral surface of the stator core, wherein a coolant liquid is flown into the frame. In a motor cooling device for cooling a stator, the frame includes a first frame provided on an outer peripheral surface of the stator core and a second frame provided in contact with an outer peripheral surface of the first frame, A cooling device for an electric motor, comprising: a refrigerant liquid groove having a minute annular gap formed so as to extend in a circumferential direction on a surface of one of the first frame and the second frame that contacts the other. . 2. A ≧ B, where A is the cross-sectional area of the inlet of the refrigerant liquid groove viewed from the inflow direction and B is the cross-sectional area of the refrigerant liquid groove viewed from the axial direction. The cooling device for an electric motor according to claim 1, wherein the cooling devices have a relationship. 3. The refrigerant liquid groove is provided with a taper portion at least in the vicinity of an inlet of the refrigerant liquid.
Alternatively, the cooling device for the electric motor according to the item 2. 4. A stepped portion is formed at one end of the second frame in the axial direction, and the end portion of the first frame and the stepped portion of the second frame are fixed by a fastening screw in the thrust direction. The cooling device for an electric motor according to claim 1 or 2, wherein. 5. The cooling device for an electric motor according to claim 4, wherein the first frame and the second frame are fastened together in a space in which the stator coil is housed.