JP2002345181A - Rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of deformation of a case and to surely fix a stator. SOLUTION: A stator core 51 is fixed by inserting the core with pressure into the internal circumference of a cylindrical member 52. The cylindrical member 52 is formed with a non-magnetic material having a linear expansion coefficient near to that of the stator core 51. The cylindrical member 52 is coupled by spline-coupling method to the internal circumference of the case member 1 from the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine, and more particularly to a stator fixing structure.

[0002]

2. Description of the Related Art A rotating electric machine, for example, a stator of an electric motor,
Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 9-84282, a stator core is shrink-fitted to a case or fixed to the case by bolts penetrating the stator core.

[0003]

However, when the stator core is shrink-fitted into the case, the torque reaction force applied to the stator is supported by the frictional force between the stator core and the case. A member having a larger coefficient of linear expansion than a stator core requires a higher fastening force at the time of assembling because the frictional force decreases as the temperature increases.

[0004] For this reason, distortion is likely to occur in the case, and the effect of the distortion is small if the case is a simple cylindrical shape. However, when a rotating electric machine is used in an automobile, it is often combined with a transmission or a reduction gear. The shape does not become a simple cylindrical shape, and shrink-fit causes uneven deformation on the circumference. In the case where the case member to which the stator is fixed is combined with another case member (for example, a case cover) and the shaft is supported by both case members, a shaft support portion (a bearing portion, etc.) of each case member Is displaced, the shaft is tilted, the operation of the bearings and gears becomes unstable, and noise is generated.

[0005] To avoid this, there is a method of shrink-fitting the stator core into the case and then machining the case. However, the process is complicated and the cost is increased. It may impair reliability by entering.

Further, in the case where the stator core is fixed to the case by the above-mentioned bolts, it is necessary to provide a through hole for the bolt at a position avoiding the stator coil. It will be.

An object of the present invention is to solve such a problem.

[0008]

According to a first aspect of the present invention, there is provided a rotating electric machine in which a stator is fixed inside a case, and a rotor is rotatably supported on an inner peripheral side of the stator. The cylindrical member is fixed by press-fitting, the cylindrical member is formed of a non-magnetic material, and a material having a linear expansion coefficient close to that of the stator core.

According to a second aspect of the present invention, in the first aspect, the case comprises at least two case members connected to each other, one end of a rotor shaft of the rotor being one case member, and the other end being the other case member. It is supported by a member.

In a third aspect based on the first or second aspect, the linear expansion coefficient of the cylindrical member is larger than that of the stator core material and smaller than that of the case material.

According to a fourth aspect of the present invention, in the first to third aspects, the spline connection determines the fitting at the time of assembling such that the radial gap at a high temperature is substantially zero.

According to a fifth aspect, in the first to fourth aspects, a pair of spline portions are provided on both sides in the axial direction of a cylindrical member formed to be longer in the axial direction than the stator core, and these spline portions are formed on the inner periphery of the case. And the spline portions are spline-coupled to each other, and the pair of spline portions are arranged outside the stator core in the axial direction.

In a sixth aspect based on the fifth aspect, a cooling passage is formed between the spline portion on the inner periphery of the case and the spline portion on the outer periphery of the cylindrical member, and cooling oil is guided to the cooling passage. .

According to a seventh aspect of the present invention, in the sixth aspect, an annular refrigerant chamber is defined at both ends of the stator in the case, and cooling oil guided to these refrigerant chambers is supplied to the cooling passage. I let it flow.

[0015]

In the present invention, the stator core is press-fitted into the inner periphery of the cylindrical member having a close coefficient of linear expansion, and the cylindrical member is spline-bonded to the inner periphery of the case. The change in interference at the time is small, so even if the press-fitting during assembly is not increased, the loosening does not occur at high temperatures, so the initial deformation of the cylindrical member can be reduced, and the thickness of the cylindrical member also increases accordingly Be reduced.

[0016] Further, the spline connection between the cylindrical member and the case allows the torque reaction force of the stator to be supported not by frictional force but by a tooth surface, so that the stator can be reliably supported without excessive interference. Can be made as small as possible.

According to the fourth aspect of the present invention, no radial gap is formed in the spline portion even at a high temperature, and it is possible to avoid the deterioration of output characteristics and the induction of vibration due to the variation in the gap between the stator and the rotor.

Further, in the fifth aspect, since the spline portion is arranged outside the stator core in the axial direction, the fitting at the time of assembly can be determined only by the relationship between the cylindrical member and the case without including a highly rigid stator core. In addition, the amount of deformation of the case can be suppressed.

In the sixth and seventh inventions, by cooling the space between the cylindrical member and the case with the cooling oil, the heat generated by the stator coil can be efficiently released, the cooling performance can be improved, and the deterioration of the output performance can be prevented. .

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example in which the present invention is applied to a motor unit. A motor unit 3 and a reduction gear unit 7 are arranged in a case.

A motor part 3 is housed in a case member 1 which is a part of a case, and a case member 2 in which a speed reducer part 7 is housed is mounted on a side surface thereof. A cover as another case member 8 is attached.

The motor section 3 is composed of a stator 5 and a rotor 6. The stator 5 is fixed to the case member 1, and the rotor shaft 6a is freely rotatable between the bearing 1a of the case member 1 and the bearing 8a of the case member 8. Supported by

The reduction gear unit 7 is composed of an input gear 11a and an output gear 11b. The input gear 11a is provided between the bearing 1b of the case member 1 and the bearing 2a of the case member 2.
The output gear 11b is rotatably supported between the bearing 1c of the case member 1 and the bearing 2b of the case member 2.

The rotor shaft 6a of the motor section 3 is connected to the input gear 11a of the reduction gear section 7, so that the output of the motor section 3 is transmitted to the reduction gear section 7.

Next, a structure for fixing the stator 5 to the case member 1 will be described with reference to FIG.

The stator 5 is constructed by winding a coil 50 around a stator core 51 in which thin electromagnetic steel sheets are laminated.
The stator core 51 is fixed to the inner periphery of the cylindrical member 52 by press-fitting such as shrink-fitting, which is formed of a nonmagnetic material whose coefficient of linear expansion does not significantly differ from that of the stator core 51.
Preferably, the cylindrical member 52 has a linear expansion coefficient larger than that of the stator core 51 and the case member 1
, For example, stainless steel.

The cylindrical member 52 is formed to be longer in the axial direction than the stator core 51, and a pair of spline portions 53a and 53b extending in the axial direction are provided on both sides of the outer periphery thereof. Spline 53
The spline portion 53 that engages with the a and 53b is formed, and the cylindrical member 52 is fixed to the case member 1 by spline engagement.

At both ends of the stator core 51, annular members 61a and 61b extending on an extension of the inner peripheral surface thereof are arranged, and these annular members 61a and 61b are disposed between the inner peripheral surfaces of the case members 1 and 8, respectively. The refrigerant chambers 58 and 59 which are closed annular spaces are defined before and after the stator 5. Refrigerant chamber 58
Cooling oil is supplied to the stator core 51.
Flows in the axial direction via the status lot accommodating the stator coil 50 and is guided to the refrigerant chamber 59.

A cooling passage 54 is formed between the outer peripheral portion of the cylindrical member 52 and the inner peripheral portion of the case member 1 at a spline engagement portion, and the cooling oil in the refrigerant chamber 58 is supplied to the cooling passage 54. Through the cutout 54 a provided at the right end of the cylindrical member 52, it is discharged to the refrigerant chamber 59. In this case, the cooling oil flows from the inner diameter side gap 56 of the spline portion 53a to the cooling passage 54, passes through the inner diameter side gap 57 of the opposite spline portion 53b, and passes through the cutout portion 54a.
To reach.

The outer diameter sides of the spline portions 53a and 53b are press-fitted without any gap with the root surface of the spline portion 53.
This prevents the cylindrical member 52 from moving in the axial direction. The notch 55 is formed at the end of the cylindrical member 52, but is desirably provided above the cooling passage 54 in order to release air.

With this structure, the difference between the linear expansion of the portion where the stator core 51 and the cylindrical member 52 are shrink-fitted is small. Therefore, even if the stator core 51 becomes hot due to the heat generated by the stator coil 50, it is assembled. The change of the interference between the time and the high temperature is small, and the press-fitting force at the time of assembly can be reduced as compared with the related art. Therefore, the thickness of the cylindrical member 52 can be reduced, and the size of the unit can be reduced.

Next, the cylindrical member 52 and the case member 1 are fixed by spline engagement. In order to support the torque reaction force of the stator 5, the engagement length (axial length) of the spline is set to a tooth. Since the surface pressure, tooth root bending, and shear stress only need to be satisfied, the torque reaction force of the stator 5 can be supported with a minimum necessary length by increasing the number of teeth.

The engagement by the spline can be controlled by providing a gap and sliding in the axial direction, by tightly fitting and fixing, or by selecting various conditions. Since the case member 1 is formed of an aluminum alloy, the gap is widened as the temperature rises. For this reason, the specifications at the time of assembly (room temperature) are determined so that the gap becomes zero at the time of high temperature. Also, it is possible to prevent gaps from occurring in the radial direction and the circumferential direction, and it is possible to prevent the radial gap with the rotor 6 from being biased and to prevent the generation of vibration noise due to rattling.

Further, since the spline portions 53a and 53b provided on the outer periphery of the cylindrical member 52 are arranged outside the stator core 51 in the axial direction, the amount of distortion of the case member 1 can be reduced.

Since the spline joint between the cylindrical member 52 and the case member 1 is outside the stator core 51 having high rigidity, the case member 1 is spline-joined.
Is not directly related to the amount of deformation of the stator core 51. If a spline is provided on the stator core 51, the iron-based component obtained by adding the thickness of the stator core 51 to the thickness of the cylindrical member 52 and the aluminum alloy case member 1 will be press-fitted to ensure the same interference. Then, it can be easily understood that the deformation of the case member 1 increases as compared with the present invention.

Of the spline portions 53a 53b on both sides,
It is conceivable to press-fit one side without a spline,
If the torque reaction force of the stator 5 is not designed to be mainly received on the spline side, the interference of the press-fitted portion without the spline becomes large, and eventually the deformation of the case member 1 becomes large. Further, as described above, regarding the spline specifications, the thickness of the cylindrical member 52 and the case member 1 can be reduced by supporting a predetermined torque reaction force by reducing the size of the module and increasing the number of teeth. This is advantageous for miniaturization of the entire unit.

Further, regarding the stator coil 50 which generates heat from the stator 5, cooling oil flows between the outer periphery of the cylindrical member 52 and the inner periphery of the case member 1 between the refrigerant chambers 58 and 59 provided before and after the stator core 51. 54, and flows in the axial direction in the status lot, so that heat can be effectively radiated and cooled.

In this case, by flowing cooling oil between the outer periphery of the cylindrical member 52 and the inner periphery of the case member 1, heat of the stator coil 50 is transferred from the cylindrical member 52 to the case member 1 via the cooling oil. The heat can be dissipated, and the heat dissipating property is remarkably improved as compared with the case where the air layer is simply used.

In the above-described embodiment, the present invention is applied to the motor unit. However, it is of course possible to apply the present invention to a generator or a generator unit.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea of the invention described in the appended claims.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case member 2 Case member 3 Motor part 5 Stator 6 Rotor 7 Reduction gear part 8 Case member 50 Stator coil 51 Stator core 52 Cylindrical member 53 Spline part 53a, 53b Spline part 54 Cooling passage 55 Notch 58 Refrigerant chamber 59 Refrigerant chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H002 AA04 AA08 AB04 AC00 AC06 5H615 AA01 BB01 BB02 PP01 PP06 PP25 PP28 SS09 SS10 SS15

Claims (7)

[Claims] 1. A rotating electric machine in which a stator is fixed inside a case, and a rotor is rotatably supported on an inner peripheral side of the stator, wherein a stator core is fixed to an inner periphery of the cylindrical member by press-fitting, and the cylindrical member is fixed. A rotating electric machine formed of a magnetic material and having a coefficient of linear expansion close to that of the stator core, and wherein the cylindrical member is spline-coupled to an inner periphery of the case from an axial direction. 2. The case according to claim 1, wherein said case comprises at least two case members connected to each other, one end of a rotor shaft of said rotor being supported by one case member and the other end being supported by the other case member. The rotating electric machine as described. 3. The linear expansion coefficient of the cylindrical member is larger than the material of the stator core and smaller than the material of the case.
Or the rotating electric machine according to 2. 4. The rotating electric machine according to claim 1, wherein said spline connection determines the fitting at the time of assembly such that a radial gap at a high temperature is substantially zero. 5. A pair of spline portions are provided on both sides in the axial direction of the cylindrical member formed longer in the axial direction than the stator core, and these spline portions are spline-coupled to spline portions on the inner periphery of the case. The rotating electric machine according to any one of claims 1 to 4, wherein the spline portions are respectively arranged outside the stator core in the axial direction. 6. The rotating electric machine according to claim 5, wherein a cooling passage is formed between the spline portion on the inner periphery of the case and the spline portion on the outer periphery of the cylindrical member, and cooling oil is guided to the cooling passage. 7. The cooling device according to claim 6, wherein annular coolant chambers are defined at both ends of the stator in the case, and cooling oil guided to the coolant chambers flows through the cooling passage. Rotating electric machine.