JPH04185244A - Stator of wheel motor - Google Patents

Abstract

PURPOSE:To secure a stator to the inside of a case accurately by a simple structure without using bolts by forming key slots with one or more spiral grooves formed on the outer surface of the stator which is made by laminating silicon steel plates with notches made on the outer surface being slid little by little and grooves formed on the inner surface of the case and by inserting spheres or elastic bodies into the slots as keys. CONSTITUTION:Notches 115 are made on a silicon steel plate 113 and a plural number of such silicon steel plates 113 are so laminated that the notches 115 may form spiral grooves. Thus fabricated cylindrical stator has spiral grooves 103 on its outer surface. The laminated silicon steel plates 113 are fixed to each other by some method or other so that the stator may not be disassembled. After that, a coil is wound round the stator. On the inner surface of a motor case 10 into which the stator 21 would be inserted, inner grooves 119 are formed which would correspond to the grooves formed on the stator. Then, the stator 21 is inserted into the case 10, with the result that key slots are formed by the grooves 103 of the stator and the inner grooves 119 of the case. Steel balls 105 are inserted into the key slots. After that, a snap ring 111 is put on the top to close the key slots.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stator for a wheel motor used in an electric vehicle.

[Conventional technology]

Generally, the stators of DC brushless motors and AC motors are made of laminated silicon steel plates, iron plates, etc., wound with coils, and press-fitted into an aluminum case. in this case,
Aluminum has a higher coefficient of thermal expansion than steel or silicon steel.
At high temperatures, the aluminum case expands more, weakening the binding force between it and the stator, and the stator may move due to the reaction force of rotor rotation, so it is necessary to provide a tightening mechanism to prevent this. For example, when considering iron and aluminum, the thermal expansion coefficient of iron is 11°7 x 10
-'/l, and if the outer diameter of the stator at a temperature of 20°C is 180.06 mm, then at 100°C it is 180.06 mm.
．． It will be 23mm. Therefore, at a temperature of 20°C, the inner diameter of the aluminum case is the same as the outer diameter of the stator at 100°C.
The inner diameter of the case at ℃ is 179.90 seconds, and the interference at this time is 180.06-179.9=0.1.6 mm. Therefore, it can be seen that in order to prevent the stator from rotating even at high temperatures, the interference is required to be 0.16 un or more. In reality, the stator is prevented from rotating by securing it with a holset bolt with a certain amount of tightening allowance for press-fitting.

[Problems to be Solved by the Invention] In the wheel motor of an electric vehicle, the stator must be completely fixed to the case in order to prevent a decrease in motor efficiency due to deviation in position detection of a position detector, for example, a resolver. However, if the interference is set large so that the stator does not move even when the temperature rises, a large stress may be applied to the case when it cools down, which may cause it to break. On the other hand, if the interference is reduced to prevent damage, the stator will rotate at high temperatures and will no longer function as a motor. Conventionally, holset bolts have been used for this purpose, but due to the shape of the case and built-in components such as wheel motors, it may be difficult to use bolts due to the structure, such as the inability to insert tools.

The present invention is intended to solve the above problems, and aims to provide a stator for a wheel motor that can securely fix the stator to the case with a simple structure without using a holset bolt. do.

[Means to solve the problem]

A stator for a wheel motor according to the present invention is a stator for a wheel motor that is press-fitted into a case and fixed therein, in which the stator has one or more notches formed on the outer circumferential surface of each laminated plate, and the position of the notch is determined. Shift sequentially and multiply 1
As a result, a spiral groove is formed on the outer peripheral surface, a groove is formed on the inner surface of the case, and a spherical or elastic groove is formed in the keyway formed by the spiral groove on the outer peripheral surface of the stator and the groove on the inner surface of the case. It is characterized in that the body is inserted and the stator is fixed to the case.

[Action and effect of the invention]

In the present invention, notches are provided on the outer peripheral surface of laminated plates such as silicon steel plates and iron plates, and by stacking the laminated plates with these notches shifted, one or more IJx spiral grooves are formed on the outer peripheral surface of the stator. A key groove is formed by the groove provided in the groove and the spiral groove. A sphere or elastic body is inserted here as a key to fix the stator to the case, so the stator can be fixed to the case without using a holset bolt, and it can be used for built-in motors like wheel motors. It can also be applied to

In addition, since there is no need to provide an excessive tightening margin, the case will not be destroyed at low temperatures, and the stator can be reliably prevented from rotating even at high temperatures. Since misalignment can be prevented, it is also possible to prevent a decrease in motor efficiency.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining the stator of the wheel motor of the present invention, FIG. 2 is a conceptual diagram of a motor case, and FIG. 3 is a plan view when the stator is fixed to the case. In the figure, 1
0 is the motor case, 21 is the stator, 103 is the groove, 10
5 is a steel ball, 111 is a snap ring, 113 is a silicon steel plate, 115 is a notch, and 119 is an inner groove.

The stator 21 is a silicon steel plate 11 as shown in FIG. 1(b).
3, or one insulated from each other and laminated to form a cylindrical shape. The silicon steel plate 113 has comb-like internal teeth 11.
4 to form a slot when stacked. If the silicon steel plates are stacked so that the slots form a straight line parallel to the axial direction of the cylinder, the magnetic circuit becomes non-uniform depending on the rotational position of the rotor, resulting in a cogging phenomenon in which the torque fluctuates. In order to prevent this and obtain a smooth torque, the slots are formed diagonally, and the slots are stacked so that they are shifted by, for example, one slot pitch over the entire length of the stator.

A coil is wound through the slot formed in this way, and forms a magnetic circuit facing, for example, a magnet of the rotor inserted inside, and generates a rotational force to the rotor when the coil is energized. It looks like this.

For example, if four notches 115 are provided in this silicon steel plate and the sheets are stacked to form diagonal slots, the cylindrical surface of the stator will have spiral grooves 103 as shown in FIG. 1(a).
is formed. In order to prevent the stator stacked in this way from coming apart, the coils are wound while being fixed in some way.
A sphere such as a steel ball 105 is inserted into each groove, and the top is fixed with a snap ring 111.

On the other hand, the motor case 10 into which the stator 21 is inserted has a groove 1 formed by the stator as shown in FIG.
03, four inner grooves 119 are formed.

The stator is inserted into the case 10 while the case is heated to a high temperature and expanded, and the stator is kept at room temperature. This creates a gap between the case and the stator, allowing for easy insertion.

FIG. 3 is a plan view showing the stator 21 inserted into the case 10.

A steel ball 105 is inserted into a groove formed by a groove 103 in the stator and an inner groove 119 in the case. As a result, even if a gap is created between the case and the stator due to a difference in thermal expansion, the steel balls will fix the gap between the two, thereby preventing the stator from moving.

Note that when actually inserting the steel ball into the keyway, there is a possibility that the steel ball may pop out in the condition shown in Figure 1 (a), so the stator is inserted in a case with high humidity, and the steel ball is inserted in that state. The balls may be poured one after another from above, and the top may be stopped with a snap ring 111 to cover the groove so that the steel balls do not jump out from the top. Of course, if the groove 103 is shaped so that the steel balls do not fly out, the stator may be inserted into the case after being placed in the groove 103 in advance.

Further, in the above description, all the grooves are used as key grooves, but for example, two of the grooves 103 facing each other are used as key grooves.
．． It is also possible to use 103 as a welded portion for fixing a silicon steel plate, and in that case, there is no need to provide an inner curvature in the case in the portion facing the welded portion. The stator may be fixed by any method other than welding, for example, the laminated plates may be fixed by adhesive.

In addition, in the above explanation, the stator groove 103 and the case inner groove 109 were made to completely match to insert the steel balls, but by making sure that both grooves cross somewhere, the case can be heated to high temperatures. The stator can also be fixed by cooling the stator by inserting steel balls only in the position where both grooves cross.

Furthermore, the object inserted into the keyway is not limited to a steel ball, but any spherical object with high rigidity may be used, and an elastic object such as a spring may also be inserted therein.

FIG. 4 is a sectional view showing one embodiment in which the stator of the present invention is applied to a wheel motor with a reduction gear.

In FIG. 4, the case body 10 has a two-part structure consisting of a cylindrical support-side housing 11 and a wheel-side housing 12, both of which are fixed with bolts (not shown). Further, the support side housing 11 is fixed to a side opposite to the wheel side housing 12 with a plate 13 and a cover 14 with bolts (not shown), and is fixed with bolts 62 to a support 61. Further, an oil pump motor 16 is provided at the bottom, and is configured such that oil is circulated and cooled from an oil reservoir 18 at the bottom through an oil passage formed between the plate 13 and the cover 14. An oil seal 19 is provided on the inlet side of 16. A large number of cooling fins 15 and heat vibrators 17 are provided on the outer peripheral surface of the cover 14 . and,
An electric motor 20 having a flat, hollow rotor 23 is housed inside the case body 10, and a planetary gear reduction gear W30 is housed in the hollow portion of the rotor 23.

The stator 21 of the electric motor 20 is fixed to the inner wall of the housing 12, and is formed with a spiral groove as shown in FIG. The top is fixed with a snap ring 111. A coil 22 is wound around the stator 21.

The rotor 23 of the electric motor 20 is composed of a hollow iron core, and a permanent magnet 24 is fixed to the outer periphery with a retaining band.
A thin section 26 protruding from the end surface of the permanent magnet 24 is provided at the blade end thereof, and is rotatably supported by this thin section 26 and the opposite ends thereof. In the illustrated example, one end thereof is supported by a ball bearing 41 on the housing ll side, and the other end is supported by a ring gear 31 of the planetary gear reduction device 30.
The ring gear 31 of the planetary gear reduction device 30 is press-fitted into the housing 12 and fixed with bolts. Further, the sun gear 33 of the planetary gear reduction device 30 is connected to the housing 11.
It is supported by a ball bearing 43 on the side and is spline-fitted into the hollow inside of the rotor 23 . The rotation of the resolver shaft 37 inserted and fixed into the sun gear is detected by the resolver 36. Also,
The sun gear is hollow, and lubricating oil is supplied to this part through an oil passage, and the part communicating from the oil passage to the hollow part of the sun gear is sealed by a seal ring 38. The pinion shaft 34 is connected to an output carrier 51 serving as an output rotating shaft, and the pinion gear 32 is rotatably supported by the pinion shaft 34 with a needle bearing 45 and is arranged so as to always mesh with the ring gear 31 and sun gear 33. ing.

The output flange 52 is connected to the output carrier 5
A double-row angular bearing 44 is spline-fitted to the outer periphery of the ring gear 1 and fixed so as not to be movable in the axial direction by a nut 53, and is engaged with the pinion gear 32 of the ring gear 31.
Supported by Double row angular bearing 4
Lubricating oil is supplied to the area 4 through an oil passage, and the area is sealed with an oil seal 39. A brake disc plate 56 is spline-fitted to the output 7 flange 52, and
A wheel 54 holding a tire 55 is attached with bolts and nuts.

The support 61 includes an angular bearing 46 and a nut 6.
4 is rotatably supported by a knuckle 63, and a cover internal 66 is fixed to this knuckle 63 with bolts. Then, the internal gear 65 is connected to the steering lever 6.
7 with bolts, and the cover internal 66 is fixed by a ball bearing 47 and a needle roller bearing 48.
It is rotatably supported by the support 61 and arranged to mesh with the support 61. When the internal gear 65 rotates as the lever 67 is steered in this manner, the rotation angle is amplified by, for example, twice, and the support 61 is rotated. Further, a brake pipe 109 for transmitting hydraulic pressure is connected to a brake connector 71 and is connected to a brake disc plate 5.
Hydraulic pressure to press the brake pads is supplied to 6.

Even if the motor is built-in as described above, the stator and case are fixed by steel balls inserted into the spiral keyway, so they can be fixed without using bolts. In addition, since the planetary gear reduction device 30 is arranged using the hollow part of the rotor 23, the length in the axial direction can be shortened to make it flat and compact, or high-speed rotation can be made possible to improve acceleration and deceleration performance. In this case, if the rotor is made flat and its diameter is increased, the distance between the two points of support will inevitably become narrower, and the influence of misalignment on the inclination of the shaft will increase, and the inclination of the rotor will cause the stator to This causes variations in the spacing between the magnets and the rotor magnets, and as a result, variations in torque demand occur. To solve this problem, in this embodiment, a thin wall part is provided next to the rotor, and the rotor is supported at two points near the outer circumference of the rotor at both ends, so that the diameter of the support part can be increased. Furthermore, homogeneity can be improved, and fluctuations in the inclination of the rotor and the gap between the rotor and the stator can be reduced.

Further, the ring gear 31 is fixed to the housing 12, and the output flange 52 and the output carrier 51 are supported by a double-row angular bearing 44 inside the ring gear 31, and the sun gear 33 is supported by the ball bearing 43 in the housing 11. Here, if the rotor 23 of the motor 20 and the sun gear 33 (man-powered gear of the reduction gear) are directly connected, the inclination of the rotor will affect the tooth contact of the sun gear 33, which is the input gear, and the durability of the gear will increase. It has a significant negative impact on sexuality. Therefore, in this embodiment, the rotor and sun gear are separated and supported by separate bearings as described above, and both are spline-fitted. Therefore, the input gears are supported by the self-aligning function, and a structure that allows different axes of the input gears to be tilted can be realized. As a result, the inclination of the shaft due to misalignment can be eliminated, the comradeship of the planetary gear reduction device 39 can be improved, and the variation in performance due to the inclination of the rotor can be eliminated.

As described above, in the present invention, in order to prevent the torque cogging phenomenon from occurring, the spiral grooves on the outer circumferential surface of the stator, which are formed by gradually shifting the notches of the laminated plates and the grooves provided on the inner surface of the case, are used. By forming a keyway and inserting a sphere or elastic body into it to fix the stator to the case, it is possible to fix the stator to the case without using a holset bolt, and it is possible to fix the stator to the case without using a holset bolt. It can also be applied to built-in stamps. Further, since there is no need to provide an excessive tightening margin, the case will not be destroyed at low temperatures, and rotation of the stator can be reliably prevented even at high temperatures.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the stator of the wheel motor of the present invention, Figure 2 is a conceptual diagram of the motor case, Figure 3 is a plan view when the stator is fixed to the case, and Figure 4 is a diagram for explaining the stator of the wheel motor of the present invention. FIG. 2 is a sectional view showing an embodiment I in which a stator is applied to a wheel motor with a reduction gear. 21... Stator, 103... Groove, 105... Steel ball, 111... Snap ring, 113... Silicon steel plate, 115... Notch, 10... Motor case, 11
9...Inner groove. Applicant Aisin AW Co., Ltd. Representative Patent Attorney Masanobu Hirukawa (7 others) Figure 1 (a) (b) Figures 2 and 3 1υb

Claims (1)

[Claims] (1) In the stator of a wheel motor in which the stator is press-fitted into the case and fixed, the stator is laminated by sequentially shifting the positions of the notches of each laminated plate having one or more notches formed on the outer peripheral surface. A spiral groove is formed on the outer peripheral surface of the stator, a groove is formed on the inner surface of the case, and a sphere or an elastic body is placed in a keyway formed by the spiral groove on the outer peripheral surface of the stator and the groove on the inner surface of the case. A stator for a wheel motor, characterized in that the stator is inserted into a case and fixed to the case.