JPH10336966A - Cooling structure for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable cooling structure for motor which can exhibit a sufficient cooling effect. SOLUTION: Holding members 40 and 70 and respectively provided at both ends of a stator 12 having a plurality of salient poles 13a and 13b, 14a and 14b, 15a and 15b, 16a and 16b, 17a and 17b, and 18a and 18b wound with coils 20, 21, and 22 in the axial direction and the members 40 and 70 are coupled with the stator 12 by fixing both ends of a plurality of hollow connecting shafts 30 which are passed through the stator in the axial direction to the members 40 and 70 and, at the same time, flow passages for a cooling fluid are formed in the hollow sections 31 of the connecting shafts 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor cooling structure in which coils are wound around a plurality of salient poles of a stator, respectively.

[0002]

2. Description of the Related Art As a conventional cooling structure for a motor of this type, the following four structures are generally known. (1) A natural air cooling structure in which fins are provided outside the motor (such as a housing).

(2) A forced air cooling structure in which fins are provided inside or outside a motor housing, and cooled air outside is taken in and discharged inside or outside the motor.

(3) A water cooling structure in which a water cooling passage is provided inside the motor.

(4) An oil cooling structure by spraying oil from a motor shaft.

[0006]

However, in the above-mentioned structure (1), the cooling effect cannot be expected due to the absence of wind or the like depending on the installation location of the motor, and the cooling effect cannot be expected because of being far from the heat source. Is much smaller. Also,
Although the structure of (2) is generally used frequently, when dust and water are present in the use environment, the motor has a closed structure, and the cooling effect is reduced. Also, in the structure of (3), the cooling effect is small because it is far from the heat source. Further, in the case of a housing made of a casting, water may leak to the outside and inside of the motor in a casting cavity or the like.To prevent this, if the thickness of the casting is increased more than necessary, the weight of the motor increases and Invites upsizing. In addition, the provision of the water passage in the casting housing requires a very complicated mold, which leads to an increase in the manufacturing cost of the motor. Also,
According to the structure (4) described above, foreign matter is likely to be generated due to deterioration of oil or the like, and the foreign matter may be clogged in the oil ejection holes or passages, and the cooling effect may be lost, resulting in low reliability.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a highly reliable motor cooling structure capable of obtaining a sufficient cooling effect.

[0008]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned problems is that a holding member is provided at each of both axial ends of a stator having a plurality of salient poles around which a coil is wound. The stator is connected to the holding member by fixing both ends of a plurality of hollow connection shafts penetrating the stator in the axial direction to the holding member, and a cooling fluid is provided in a hollow portion of the connection shaft. Is formed.

In the above-mentioned means, the holding member may be formed with a communication path for communicating the flow paths formed in the adjacent connection shafts with each other.

According to this means, since cooling can be performed near the coil of the heat source, a great cooling effect can be obtained. In addition, by effectively utilizing the inside of the connection shaft connecting the stator and the holding member as a flow path, space can be saved and weight can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motor cooling structure according to the present invention will be described below with reference to the drawings.

1 to 5 show an example in which the present invention is applied to a switched reluctance motor. In FIG. 1, a switched reluctance motor 10 has a cylindrical housing 11 made of aluminum or the like. Housing 1
As shown in FIG. 2, holding members 40, 70
The brackets 61 and 80 are fixed via the. A cylindrical stator 12 is provided in an inner hole 11 a of the housing 11.
Are arranged. The stator 12 is formed by laminating annular magnetic steel sheets, and has an outer peripheral portion fixed to an inner hole 11 a of the housing 11 by shrink fitting.

The stator 12 has six pairs of stator pole portions 13a, 13b; 14a, 14b; 1 which protrude at regular intervals so as to face each other inward in the radial direction and extend in the axial direction.
5a, 15b; 16a, 16b; 17a, 17b; 18
a and 18b. Each pair of the stator pole portions, for example, the stator pole portions 13a, 13b; 16
A coil 20 is wound around each of a and 16b and connected in series. Similarly, two pairs of stator poles 1
4a, 14b; 17a, 17b and 15a, 15b; 1
Coils 21 and 22 are wound around 8a and 18b, respectively. Each coil is connected to a drive circuit (not shown).

A rotor 2 formed by laminating electromagnetic steel sheets
3 has a central hole in the axis thereof, and as shown in FIG.
The first output shaft 28 rotatably supported via 63 is fitted into the first output shaft 28, and both are integrally rotated via a key. Thereby, the rotor 23 can rotate integrally with the output shaft 28 in the stator 12. The first output shaft 28 has a hollow shape, and is internally splined at one end to the first output shaft 28 and connected at the other end to a speed reducer (not shown). The second output shaft 29 which allows a predetermined twist is provided. Further, the rotor 22 is provided with four pairs of rotor pole portions 2 which protrude radially outward at equal intervals in directions opposite to each other and extend in the axial direction.
4a, 24b; 25a, 25b; 26a, 26b; 27
a, 27b. Each of these rotor pole sections 24
a, 24b; 25a, 25b; 26a, 26b; 27
As shown in FIG. 1, the stator poles 13a, 13b;
a, 14b; 15a, 15b; 16a, 16b; 17
a, 17b; when facing the 18a, 18b, a predetermined gap is maintained between them. In the present embodiment, as shown in FIG.
The rotor 23 includes rotor pole portions 24a, 24b;
26a, 26b; 27a, 27b and the output shaft 28 are formed with axial holes 23b extending in the axial direction, respectively. These shaft holes 23b reduce the radial rigidity of the rotor pole portion, absorb the impact due to the suction force acting on the rotor pole portion, and prevent the impact from being transmitted to the output shaft 28. In addition, a shaft hole 23a is formed in each rotor pole portion on the anti-rotation direction side, so that a sudden decrease in magnetic attraction force when current supply to each coil is stopped is reduced, and vibration and noise accompanying vibration are reduced. I do.

At one end of the output shaft 28, a well-known rotation sensor such as an encoder or a resolver is disposed for detecting the rotation position of the rotor 23. The rotation sensor is electrically connected to a controller (not shown), and a position signal and an angle signal of the rotor 23 detected by the rotation sensor are sent to the controller (not shown).
The controller includes: stator pole portions 13a and 13b;
14a, 14b; 15a, 15b; 16a, 16b; 1
7a, 17b; electrically connected to a drive circuit (not shown) to which coils wound around 18a, 18b are connected, and transmits an output signal to the drive circuit in accordance with a position signal and an angle signal of the rotation sensor. The drive circuit is configured by an inverter including a switching element such as a transistor or a thyristor, and supplies a current to each coil according to an output signal of a controller corresponding to a position signal and an angle signal of the rotor 23 detected by the rotation sensor. Supply in pulse form.

In this embodiment, as shown in FIGS. 1 and 2, the stator 12 has 13a, 13b;
14b; 15a, 15b; 16a, 16b; 17a, 1
7b; 12 through holes 12a, 12b, 12c, 1 each located on the same circle in the radial outer peripheral portion of 18a, 18b
2d, 12e, 12f, 12g, 12h, 12i, 12
j, 12k, and 12l are formed, and hollow through bolts (connection shafts) 30 are passed through the respective through holes.
The through bolt 30 is press-fitted into each through hole or
They are fitted with a predetermined small gap.

As shown in FIGS. 3 and 4, the holding members 40, 70 have twelve holes 40a, 4a at the same positions as the through holes.
0b, 40c, 40d, 40e, 40f, 40g, 40
h, 40i, 40j, 40k, 40l and 70a, 70
b, 70c, 70d, 70e, 70f, 70g, 70
h, 70i, 70j, 70k, and 70l are formed, and one end and the other end of the through bolt 30 are fitted into each hole. A half-moon-shaped head is formed at one end of each through-bolt 30, and the head is non-rotatably fitted to a housing formed at one end of each hole of the holding member 40. The through-bolt 30 is formed with a hollow portion 31 that is open at one end and extends to the fitting portion with the holding member 70 at the other end. As shown, the plug 38 is press-fitted and fixed.

As shown in FIG. 5, an annular groove 3 is formed on the outer peripheral surface on one end side of the through bolt 30 fitted into each hole of the holding member 40.
2a are formed, and the annular groove 32a is
It communicates with the hollow part 31 via four communicating holes 32 formed. Further, a pair of annular grooves are formed on the outer peripheral surface of the through bolt 30 at both ends in the axial direction of the annular groove 32a,
O-rings 34 and 35 that are in contact with the inner peripheral surface of the hole of the holding member 40 in a liquid-tight manner are fitted into the respective annular grooves. Similarly, the through bolt 30 fitted into each hole of the holding member 70
An annular groove is formed on the outer peripheral surface on the other end side of the, and the annular groove communicates with the hollow portion 31 through two or four communication holes 33 radially formed. A pair of annular grooves are formed on the outer peripheral surfaces of the through bolts 30 at both ends in the axial direction of the annular grooves, and each annular groove is in contact with the inner peripheral surface of the hole of the holding member 70 in a liquid-tight manner. Rings 36 and 37 are fitted respectively. Thus, the hollow portions of the through bolts 30 are hermetically sealed, respectively.

As shown in FIG. 3, the holding member 30 has six communicating holes 41, 42, 43, 44,
45 and 46 are formed. Each communication hole 41, 42, 4
3, 44, 45, and 46 are holes 40 adjacent to each other.
a and 40c, 40e and 40g, 40i and 40k, 40b
And 40d, 40f and 40h, and 40j and 40l. In the present embodiment, each communication hole 41, 42, 4
3, 44, 45, and 46 are formed by drilling or the like from the outer peripheral surface of the holding member 40, and the openings of the communication holes are closed by plugs 47, 48, 49, 50, 51, and 52. Similarly, adjacent holes may be communicated with each other by grooves such as those described above. In FIG. 3, the holes 55, 56, 57, 58,
59 and 60 are mounting holes for fixing the holding member 40 to the bracket 61 with bolts (not shown).

As shown in FIG. 4, the holding member 70 has six communication holes 71, 72, 73, 74,
75 and 76 are formed. Each communication hole 71, 72, 7
3, 74, 75, and 76 are holes 70 adjacent to each other, respectively.
a and 70l, 70e and 70c, 70i and 70g, 70b
And 70k, 70f and 70d, and 70j and 70h, and the communication holes 41, 42, 4
The holes through which the holes 3, 44, 45, and 46 communicate are shifted by one in the circumferential direction. Each communication hole 41, 42, 43, 44, 45,
46, in the present embodiment, each communication hole 71, 72,
73, 74, 75, and 76 are formed by drilling or the like from the outer peripheral surface of the holding member 70, and the openings of the communication holes are closed by plugs 77, 78, 79, 80, 81, and 82. Similarly, adjacent holes may be communicated with each other by grooves such as those described above.

As shown in FIG. 3, the holding member 40 has an inlet 53 and an outlet 54 for the cooling fluid which extend in the axial direction so as to open at the center of the communication holes 43 and 46 located at the axially symmetric positions. A cooling fluid such as water is supplied to the inflow port 44 via a fluid conduit (not shown). The supplied cooling fluid is supplied to the holes 40i and 40k of the holding member 40 and the holes 70i and 70k of the holding member 70 through the communication hole 43.
Flows through the hollow portion 31 of the penetrating bolt 30 penetrating through to the other end side of the penetrating bolt 30, and through the communication holes 74 and 75, the holes 70 g and 70 b of the holding member 70 and the holding member 40
The fluid flows to one end of the through bolt 30 through the hollow portion 31 of the through bolt 30 passing through the holes 40g and 40b. As described above, the cooling fluid sequentially reciprocates in the hollow portions 31 of the adjacent through bolts 30 and flows out from the outlet 54 to the fluid conduit (not shown) through the communication hole 46. A nut is screwed to the other end of the through bolt 30, whereby the stator 12 is held in the axial direction by the holding members 40 and 70.

In the switched reluctance motor 10 having the above structure, four pairs of rotor pole portions 24a, 24b; 25a, 25b;
Two of 26b; 27a, 27b are six pairs of stator pole portions 13a, 13b; 14a, 14b; 15a, 1
5b; 16a, 16b; 17a, 17b; 18a, 18
When it is detected that the rotor 23 is located at a predetermined position where two rotors b start to face each other, a controller (not shown) sends an output signal corresponding to a detection signal of the rotation sensor to a drive circuit (not shown). In response to an output signal of a controller (not shown), a drive circuit (not shown) supplies a current to coils wound around the two pairs of stator poles which are beginning to face the two pairs of rotor poles. Thereby, the stator pole portion around which the coil is wound is magnetized, and a magnetic flux is generated between the stator pole portions via the rotor pole portion located therebetween. Attraction force acts between the stator pole portion and the rotor pole portion due to the magnetic flux, and torque acts on the rotor 23 so that the rotor pole portion faces the stator pole portion by the component force of the attraction force. This torque causes the rotor 2
3 is rotated, and the rotor 23 may be located at a predetermined position immediately before being completely opposed to the magnetized stator pole portion, in other words, the final effective position where the component force for applying the torque to the rotor 23 acts. When detected by the rotation sensor, the output signal of the controller in response to the detection signal of the rotation sensor causes the drive circuit to stop the current to the coil wound around the magnetized stator pole portion. Thus, the current to the coils wound on each pair of the stator pole portions where each pair of the rotor pole portions is opposed is:
The switch is turned on and off (supplied) in a pulse form by the drive circuit, and a predetermined motor torque is obtained by the action of the above-mentioned suction force. The start and stop timings of the above-described current supply are determined according to the demands of the rotation speed and the torque.

As described above, the coil which repeatedly supplies and stops the current generates heat. In the present embodiment, however, by flowing a cooling fluid such as water into the hollow portion 31 of the through bolt 30, it is effective. Is cooled. 2 to 4, a cooling fluid such as water flows from the inflow port 53 through the communication hole 43 through the holes 40 i and 40 k of the holding member 40 and the holes 70 i and 70 k of the holding member 70.
And flows toward the other end of the through bolt 30. Then, through the communication holes 74 and 75, the holes 70g and 70b of the holding member 70 and the holes 4
The fluid flows toward the one end side of the through bolt 30 through the hollow portion 31 of the through bolt 30 penetrating through 0 g and 40 b. Then, the holes 40 of the holding member 40 are
e, 40d and through-hole 30 of through-bolt 30 passing through holes 70e, 70d of holding member 70.
Flow toward the other end of the zero. As described above, the cooling fluid sequentially flows back and forth through the hollow portions 31 of the adjacent through bolts 30, and then flows out of the outlet 54 through the communication hole 46 into a fluid conduit (not shown). This effectively cools the motor with water or fluid near the coil, which is one of the heat sources of the motor.

In the present embodiment, the hollow portion 3 of the through bolt 30 connecting the stator 12 and the holding members 40 and 70 is provided.
By effectively utilizing 1 as a flow path, space saving and weight reduction can be achieved, and a large flow path area can be ensured, so that pressure loss is small and appropriate cooling efficiency can be maintained. . In addition, since a flow path is formed by the hollow portion 31 of the through bolt 30 and the communication holes provided in the holding members 40 and 70, there is no interference with a portion over the coil, and a sufficient space for wiring and connection of the coil. And a cooling structure can be obtained only by connecting a fluid conduit (not shown) to the inflow ports 53 and 54 provided in the holding member 30 in assembling the motor. Excellent cooling structure is obtained.

[0025]

As described above, according to the first aspect of the present invention, cooling can be performed at a position near the coil of the heat source, that is, the connection shaft that penetrates through the stator and connects the stator and the holding member. Therefore, a great cooling effect can be obtained.
In addition, by effectively utilizing the dead space inside the connection shaft as a flow path, space can be saved and weight can be reduced. Further, a cooling structure with higher vibration resistance can be obtained.

Further, according to the second aspect of the present invention, it is possible to prevent interference between the coil crossing portion and the communication passage, so that the assemblability of the motor can be improved.
A space-saving and highly reliable motor can be easily realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a switched reluctance motor showing one embodiment of a motor cooling structure according to the present invention.

FIG. 2 is a longitudinal sectional view of a switched reluctance motor showing one embodiment of a motor cooling structure according to the present invention.

FIG. 3 is a sectional view of a holding member 40 in FIG. 2;

FIG. 4 is a sectional view of a holding member 70 in FIG.

FIG. 5 is an enlarged cross-sectional view of a fitting portion between the holding member 40 and the through bolt 30 in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Switch reluctance motor (motor) 11 Housing 12 Stator (stator) 13a, 13b; 14a, 14b; 15a, 15b; 1
6a, 16b; 17a, 17b; 18a, 18b Stator pole portions (salient poles) 20, 21, 22 Coils 30 Through bolts (connection shafts) 31 Hollow portions (flow paths) 40 Holding members 41, 42, 43, 44, 45 , 46 communication hole (communication passage) 70 holding member 71, 72, 73, 74, 75, 76 communication hole (communication passage)

Claims (2)

[Claims] 1. A stator having a plurality of salient poles around which a coil is wound is provided with holding members at both ends in the axial direction, and the holding members are provided with a plurality of hollow connection shafts which penetrate the stator in the axial direction. A motor cooling structure in which the stator and the holding member are connected by fixing both ends, and a flow path through which a cooling fluid flows is formed in a hollow portion of the connection shaft. 2. The motor cooling structure according to claim 1, wherein a communication path that connects the flow paths formed in the adjacent connection shafts with each other is formed in the holding member.