JPH01259739A - Bearing device for electric rotary machine - Google Patents

Abstract

PURPOSE:To decrease the relative rotational speed of the inner and outer rings of a bearing, by forming the outer ring of a first bearing fitting a rotor shaft to said inner shaft and the inner ring of a second bearing fitted to a frame supporting a stator into an integral body. CONSTITUTION:A rotating shaft 4 fitted to the rotor 3 of an electric rotary machine is fitted to the inner ring of a first bearing 5. Also, a frame 1 is provided with a second bearing 8, the outer ring of said bearing 8 is fastened to said frame 1, and the inner ring 10 of said bearing 8 is formed into an integral body with the outer ring 10 of said bearing 5. Said bearings 5 and 8 are juxtaposed in the axial direction and the diameter of the inner ring of said bearing 8 is made smaller than that of the outer ring of said bearing 5. Thus, the number of relative revolutions of the inner and outer rings of a bearing is made small and the rotational speed is increased without impairing lubricating properties.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a bearing device for a rotating electric machine for a vehicle, and more particularly, to a bearing device that enables a shaft to rotate at a higher speed. .

(Prior Art) A conventional rotating electric machine for a vehicle has a structure as schematically shown in FIG. 7. Fig. 7 is a cross section taken along a plane passing through the shaft of a rotating electric machine. Reference numeral 1 in the figure is the frame of the rotating electric machine, and a stator 2 with a primary coil (not shown) wound inside the frame is attached. There is. Further, the symbol @3 denotes a rotor around which a secondary coil (not shown) is wound, and is fitted and fixed to the shaft 4.

The shaft 4 is rotatably supported by the frame 1 via a bearing 5.6, and one end of the shaft 4 is
In order to drive the wheels of the vehicle through a gear arrangement (not shown), it is interlocked with a gear arrangement via a coupling 7, and transmits the driving force of the rotating electric machine to the wheels. The bearing 5.6 is an in-shell type, and has a structure in which a large number of rollers or balls are arranged and held between an inner ring and an outer ring via a retainer.

By the way, there are constraints unique to vehicles, such as the fact that the space for the rotating electric machine is extremely small, and the fact that periodic maintenance can be easily performed to keep the rotating electric machine in good condition. Grease lubrication is a very common lubrication method because it has a simple and compact structure considering its performance.

Furthermore, in recent years, as part of efforts to improve vehicle performance, there has been a strong desire to increase starting acceleration and to reduce the weight of vehicles. One of the countermeasures is to use the rotating electric machine at high speed by increasing the gear ratio of the gears. By rotating the rotating electric machine at high speed, it is possible to improve the vehicle performance, that is, the starting acceleration, with a small torque from the rotating electric sign. Furthermore, since the torque of the rotating electrical machine is reduced, the rotating electrical machine can be made smaller and lighter. However, as mentioned above, the rotating electric machine supports the shaft 4 via the bearings 5 and 6 and rotates the rotor 3 fixed to the shaft 4 to generate driving force, so if the rotation speed of the rotor 3 is increased, However, contrary to the improvement in vehicle performance, the following problems occur in the bearing 5.6.

That is, the lubrication performance of the bearing 5.6 is reduced.

Generally, there is a phenomenon in bearings in which the lubrication performance decreases in proportion to the product of the size of the bearing and the number of rotations.

The degree of this decrease is evaluated by the dmN value, which is a lubricant term.

That is, in the case of a rolling bearing, dm is the average value of the outer diameter of the outer ring 5a and the inner diameter d of the inner ring 5b of the bearing 5, as shown in FIG. This is the relative rotation speed of the inner ring 5b. Therefore, the outer ring 5a
If it is fixed without rotating, it is the rotation speed of the inner ring 5b.

Due to the recent remarkable improvement in the performance of lubricating oils, the permissible dmN value that does not impede lubrication performance is gradually increasing. However, technological progress has been faster in improving the performance of vehicles, in other words, increasing the speed of rotating electric machines, and it can be said that increasing the speed of rotating electric machines is a measure against the dmN value.

(Problem to be solved by the invention) As mentioned above, increasing the speed of conventional rotating electric machines
There is a problem in that the dIllN value lowers the lubricity and seizure of the bearing occurs, and it is difficult to increase the speed of the rotating electric machine. Furthermore, the dmN value can be lowered by making the dimensions of the bearing as small as possible. However, due to the rigidity and strength of the shaft, the design is currently close to its limit, making it extremely difficult to increase the speed of rotating electric machines.

The present invention has been made in view of the above-mentioned problems, and aims to provide a bearing device that maintains the dmN value of the bearing at the same level as conventional bearings, while enabling higher speeds in rotating electric machines than conventional ones. .

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, a shaft on which a rotor is attached is rotatably supported in a frame that obstructs a stator in a rotating electric machine. In the bearing device, an outer ring of a first bearing whose inner ring is fitted to the shaft and an inner ring of a second bearing whose outer ring is blocked by the frame are integrally provided, and the outer ring of the first bearing and the inner ring of the second bearing are integrally provided. It is formed by integrating the inner ring of the second bearing via an intermediate body.

(Function) In the above configuration, when the shaft of the rotating electric machine is rotated,
The inner ring of the first bearing rotates together with the shaft, and the outer ring rotates at low speed in the same direction as the inner ring due to rolling friction with a plurality of rollers or balls arranged between the inner ring and the outer ring. Become. In other words, the rotation of the rotor of the rotating electric machine is shared by a plurality of bearings, and the rotation speed of the bearings can be reduced to, for example, 1/2. Furthermore, when looking at the bearing as a whole, since the outer diameter of the outer ring in a stationary state can be reduced, the speed of the rotating electric machine can be increased without increasing the dmN value of the bearing.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings. Components that overlap with the conventional configuration shown in FIG. 7 are designated by the same reference numerals and detailed explanations will be omitted.

Referring to FIG. 1, the inner ring of the first bearing 5 is connected to the shaft 4.
The outer ring of the bearing 5 and the frame 1
A second bearing 8 is provided between them. The outer ring of the second bearing 8 is supported by the frame 1, and the inner ring is integrally connected to the outer ring of the first bearing 5 via a cylindrical intermediate body 10.

As is clear from FIG. 1, the first bearing 5 and the second bearing 8 are arranged in parallel in the axial direction of the shaft 4, and the diameter of the outer ring of the first bearing 5 is larger than that of the second bearing 8. The diameter of the inner ring is made smaller. Therefore, according to this configuration, when viewed from the overall configuration of the bearing portion, the outer diameter of the outer ring in a stationary state can be reduced, and the above-mentioned dm can be reduced.

The intermediate body 10 has a cylindrical shape including a large diameter portion 10L and a small diameter portion 10S.
The outer ring of the first bearing 5 is fitted inside, and the small diameter portion 10S of the intermediate body 10 is fitted inside the inner ring of the second bearing 8. In addition, the bearing 6 that interfered with the narrow end of the shaft 4 is
This structure is exactly the same as the conventional structure shown in FIG.

In the above configuration, in the configuration of the bearing including the intermediate body 10, the rotation of the rotor 3 and shaft 4 of the rotating electric machine is transferred to the first bearing 5.
Since the second bearing 8 shares the responsibility, the number of rotations of each bearing is approximately halved.

Therefore, the permissible rotational speed of the bearings 5 and 8 based on the dmN value can be doubled, and the rotational speed of the rotor 3 of the rotating electric machine can be increased to twice the conventional speed.

In FIG. 2, the directionality of the intermediate body 10 is reversed, and the axial arrangement relationship of the first bearing 5 and the second bearing 8 in FIG. 1 is reversed, and the effect is the same as in FIG. The effect is exactly the same as that of the embodiment shown.

Figure 3 shows a plurality of bearings 5.8 on both ends of the shaft 4.
It has a two-stage bearing structure supported by a bearing 6.9, and compared to the embodiment shown in Figs. 1 and 2, it has a two-stage bearing structure on both end sides, so It is possible to increase the speed.

4 to 6 show that between the intermediate body 10 and the rotor 3,
This shows an embodiment in which a rotation adjustment device 11 that can control rotation is provided.

That is, in FIG. 4, as the rotation adjustment device 11, permanent magnets 12 having N and S magnetic poles are provided alternately in the circumferential direction of the intermediate body 10, and permanent magnets 12 having N and S magnetic poles are provided at positions opposite to the magnets 12. The rotor 3 is provided with a donut-shaped disk 13, such as an aluminum plate, which tends to generate eddy current.

Therefore, in this configuration, the intermediate body 10 is the magnet 12
Through this, the rotor 3 rotates while being accelerated in the rotational direction of the rotor 3, even though slippage occurs.

FIG. 5 shows a configuration in which the rotor 3 is provided with air holes 14, a blower fan 15 is provided on the side of the rotor 3, and a blower fan 16 is provided on the intermediate body 10.

According to this configuration, the rotation of the rotor 3 causes the wind generated by the blower fan 15 to be blown to the blower fan 16,
The rotation of the intermediate body 10 is promoted.

In FIG. 6, a plurality of fins 17 are provided protruding from the outer peripheral surface of the intermediate body 10 in order to suppress the rotational force of the intermediate body 10.

According to this configuration, the protruding fins 17 apply a brake to the rotational force, thereby reducing the effect of suppressing the rotational force.

Note that the present invention is not limited to the above-mentioned embodiments.
For example, it is possible to make the bearing have a triple or more structure, and by making various changes, other embodiments are also possible.

[Effects of the Invention] As can be understood from the description of the embodiments above, according to the present invention, the relative rotational speed between the inner ring and the outer ring in the bearing can be reduced. Therefore, it is possible to maintain the 6 mN value at the conventional level and increase the speed of the rotating electrical machine without impairing the lubricity of the bearing.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a sectional view showing another embodiment, in which the order of the bearings in FIG. 1 is reversed. FIG. 3 is a sectional view showing an embodiment in which the bearings at both ends of the shaft are arranged in two stages. FIGS. 4 and 5 are cross-sectional views of main parts showing an embodiment in which a rotation adjusting device for promoting rotation of the intermediate body is provided between the intermediate body and the rotor in the bearing device. Figure 6 shows the rotation [!] that suppresses the rotation of the intermediate body. FIG. 2 is a cross-sectional view of the main parts of an embodiment in which the device is provided. FIG. 7 is a schematic vertical assembly diagram showing the general structure of a conventional rotating electric machine for a vehicle. FIG. 8 is a longitudinal sectional view taken along a plane passing through the rotation axis of the roller bearing, and shows an example of a rolling bearing. 1... Frame 2... Stator 3... Rotor 4... Shaft 5... Bearing 5a... Outer ring 5b... Inner ring 8... Bearing 10... Intermediate body 11.・Rotation adjustment device

Claims (2)

[Claims] (1) In the frame that supports the stator of the rotating electric machine,
In a bearing device that rotatably supports a shaft to which a rotor is attached, an outer ring of a first bearing whose inner ring is fitted to the shaft and an inner ring of a second bearing whose outer ring is supported by the frame are integrated. 1. A bearing device for a rotating electrical machine, characterized in that the outer ring of the first bearing and the inner ring of the second bearing are integrated via an intermediate. (2) A bearing device for a rotating electric machine according to claim 1, characterized in that a rotation adjustment device is provided between the intermediate body and the rotor, which can adjust the rotation of the intermediate body according to the rotation of the rotor. .