JP7143033B2 - drive unit - Google Patents

Description

The present invention relates to a drive unit mounted on a hybrid vehicle (HV) or an electric vehicle (EV).

2. Description of the Related Art In recent years, vehicles equipped with a hybrid system having an engine and a drive motor as drive sources, so-called hybrid vehicles (HVs), have rapidly spread.

In an example of a hybrid system, the power of an engine is converted into electric power by a generator (motor generator for power generation), and the electric power generated by the generator is stored in a battery and used to drive a drive motor (motor generator for drive). be. The power of the drive motor is transmitted from the motor gear supported so as to rotate integrally with the rotary shaft to the differential gear, and from the differential gear to the drive wheels via the drive shaft. As a result, the vehicle equipped with the hybrid system runs.

JP 2018-33224 A

A permanent magnet magnetic field synchronous motor, for example, is adopted as a motor generator used as a generator and a drive motor. A permanent magnet field synchronous motor has a configuration in which a permanent magnet is provided in a rotor, and in a hybrid system, the rotating shaft of the rotor is rotatably supported via bearings in a case that forms the outer shell of the hybrid system. . The rotating shaft, bearings and case are all made of metal. Therefore, when the magnetic field generated by the permanent magnet of the rotor changes, a voltage is generated in the rotating shaft due to electromagnetic induction, and an induced current flows in a closed circuit formed by the rotating shaft, bearings and case. As a result, electrolytic corrosion may occur in bearings and the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drive unit that can suppress the occurrence of electrolytic corrosion in bearings and the like.

In order to achieve the above object, a drive unit according to the present invention includes a case, a rotating electric machine housed in the case and having a rotating shaft, and a sleeve-shaped member fitted on the rotating shaft, and integrated with the rotating shaft. and a plurality of bearings held by the case and rotatably supporting the rotating shaft, wherein at least one of the plurality of bearings supports the rotating shaft with the outer fitting member interposed therebetween. However, the outer fitting member is insulated.

According to this configuration, the rotary shaft of the rotary electric machine (motor, generator) is rotatably supported by the case via a plurality of bearings. An outer fitting member having a sleeve shape is fitted around the rotating shaft, and at least one of the plurality of bearings supports the rotating shaft with the outer fitting member interposed therebetween. The outer fitting member is insulated. As a result, it is possible to suppress the formation of a closed circuit by the rotating shaft, the plurality of bearings, and the case, and to suppress the flow of induced current in the closed circuit. can be suppressed.

Moreover, since the outer fitting member and the bearing overlap in the axial direction, the dimension of the drive unit in the axial direction can be reduced.

In addition, insulating means insulating the outer fitting member from other members. and the concept of applying.

According to the present invention, it is possible to suppress the occurrence of electrolytic corrosion caused by an induced current in bearings and the like, so that the life of bearings and the like can be extended.

1 is a skeleton diagram showing the configuration of a hybrid system according to an embodiment of the invention; FIG. 1 is a cross-sectional view showing a configuration of part of a hybrid system; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Hybrid system>
FIG. 1 is a skeleton diagram showing the configuration of a hybrid system 1 according to one embodiment of the invention.

A hybrid system 1 is a system mounted on a hybrid vehicle and includes an engine 2 and motor generators 3 and 4 .

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating electrical discharge in the combustion chamber. It is

Motor generator 3 (MG1) functions as a generator. A generator controller including an inverter and the like is connected to the motor generator 3 . The generator controller is connected to a battery composed of an assembled battery in which a plurality of secondary batteries are combined. The AC power output from the motor generator 3 is converted into DC power by the generator controller, and the DC power is supplied to the battery to charge the battery.

Motor generator 4 (MG2) functions as a drive motor. A motor controller including an inverter and the like is connected to the motor generator 4 . A battery is connected to the motor controller. The DC power output from the battery is supplied to the motor controller, the DC power is converted into AC power by the motor controller, and the AC power is supplied to the motor generator 4 to drive the motor generator 4 .

An engine gear 12 is provided so as to rotate together with a crankshaft 11 of the engine 2 . A generator gear 14 is provided so as to rotate together with the rotating shaft 13 of the motor generator 3 . The engine gear 12 and the generator gear 14 are in mesh with each other. The generator gear 14 has a smaller gear diameter than the engine gear 12 . Therefore, the power of the engine 2 is transmitted from the engine gear 12 to the generator gear 14 at an accelerated speed.

A motor gear 16 is provided so as to rotate integrally with the rotating shaft 15 of the motor generator 4 .

Hybrid system 1 includes counter shaft 21 , counter gear 22 and differential gear 23 . Counter shaft 21 extends parallel to rotation shaft 15 of motor generator 4 . The counter gear 22 is provided so as to rotate integrally with the counter shaft 21 and meshes with the motor gear 16 . An output gear 24 is provided so as to rotate together with the counter shaft 21 . The output gear 24 meshes with a ring gear 26 coupled to the differential case 25 of the differential gear 23 .

In the hybrid system 1, the power of the engine 2 is input from the engine gear 12 to the generator gear 14, and the motor generator 3 converts the power of the engine 2 input to the generator gear 14 into electric power.

The power of the motor generator 4 is transmitted to the ring gear 26 of the differential gear 23 via the motor gear 16, the counter gear 22 and the output gear 24, and is transmitted from the differential gear 23 via the drive shaft 27 to the vehicle in which the hybrid system 1 is mounted. is transmitted to the drive wheels 28 of the As a result, the drive wheels 28 rotate and the hybrid vehicle runs.

<Main part configuration>
FIG. 2 is a cross-sectional view showing the configuration of part of the hybrid system 1. As shown in FIG.

The hybrid system 1 includes a metal case 31 forming an outer shell. Motor generators 3 , 4 , differential gear 23 and the like are housed in a space provided inside case 31 .

The motor generator 3 employs, for example, a permanent magnet field synchronous motor including a concentrated coil winding stator 32 and a permanent magnet rotor 33 . The concentrated coil winding stator 32 is fixed to the case 31 with bolts 34 . The permanent magnet rotor 33 is fitted onto the rotating shaft 35 and fixed to the rotating shaft 35 with a lock nut 36 .

A rotor 42 of a resolver 41 for detecting the rotational phase of the rotating shaft 35 is attached to one end of the rotating shaft 35 so as to rotate together with the rotating shaft 35 . Specifically, the outer peripheral surface of one end of the rotating shaft 35 has a small diameter portion 43, a medium diameter portion 44 having a larger diameter than the small diameter portion 43, and a large diameter portion 45 having a larger diameter than the medium diameter portion 44. are formed adjacent to each other in this order. A stepped surface 46 is formed at the boundary between the medium diameter portion 44 and the large diameter portion 45 due to the step between them. The rotor 42 is formed in an annular shape and is fitted onto the medium diameter portion 44 . A lock nut 47 is screwed onto the small diameter portion 43 . By tightening the lock nut 47 , the rotor 42 is pressed between the stepped surface 46 and the lock nut 47 , thereby fixing the rotor 42 to the rotating shaft 35 .

A stator 48 of the resolver 41 is formed in an annular shape surrounding the outer circumference of the rotor 42 and fixed to the case 31 with bolts 49 .

The lock nut 47 has a sleeve portion 52 extending from the small diameter portion 43 to the end of the rotating shaft 35 . An inner ring (inner race) 53 of the bearing 51 is fixed to the sleeve portion 52 by press fitting. An outer ring (outer race) 54 of the bearing 51 is fixedly (non-rotatably) held on the inner surface of the case 31 .

On the other hand, an inner ring 56 of a bearing 55 is press-fitted to the rotary shaft 35 on the side opposite to the bearing 51 with respect to the permanent magnet rotor 33 . An outer ring 57 of the bearing 55 is fixedly (non-rotatably) held on the inner surface of the case 31 .

Thereby, the rotating shaft 35 is rotatably supported by the case 31 via two bearings 51 and 55 .

Although the lock nut 47 is made of metal, it is insulated by subjecting its surface to insulation treatment.

<Effect>
As described above, the rotating shaft 35 of the motor generator 3 is rotatably supported by the case 31 via the two bearings 51 and 55 . A lock nut 47 having a sleeve portion 52 is fitted around the rotating shaft 35 , and one bearing 51 supports the rotating shaft 35 with the sleeve portion 52 of the lock nut 47 interposed therebetween. And the lock nut 47 is insulated. As a result, it is possible to suppress the formation of a closed circuit by the rotating shaft 35, the plurality of bearings 51 and 55, and the case 31, and to suppress the flow of induced current in the closed circuit. It is possible to suppress the occurrence of electrolytic corrosion caused by

Moreover, since the lock nut 47 and the bearings 51 and 55 overlap in the axial direction, the dimension of the hybrid system 1 in the axial direction can be reduced.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, the lock nut 47 is insulated by subjecting its surface to insulation treatment, but the method of insulation is not limited to this, and a method of forming the lock nut 47 with an insulating material is adopted. may be

Further, a configuration may be adopted in which the lock nut 36 is formed to have a sleeve shape, the lock nut 36 is insulated, and the bearing 55 supports the rotating shaft 35 via the lock nut 36 .

Furthermore, in the above-described embodiment, the case where the present invention is applied to the hybrid system 1 was taken up. can be applied to

In addition, various design changes can be made to the above configuration within the scope of the matters described in the claims.

1: Hybrid system (drive unit)
3: Motor generator (rotating electric machine)
31: Case 35: Rotating shaft 47: Lock nut (outer fitting member)
51, 55: Bearing 52: Sleeve portion

Claims (1)

a case;
a rotating electrical machine housed in the case and having a rotating shaft;
an outer fitting member having a sleeve shape fitted on the rotating shaft and rotating integrally with the rotating shaft;
a plurality of bearings held by the case to rotatably support the rotating shaft ;
and a detector that detects the rotational phase of the rotating shaft ,
at least one of the plurality of bearings supports the rotating shaft across the outer fitting member;
The outer fitting member is insulated ,
The drive unit , wherein the outer fitting member fixes the rotor of the detector to the rotating shaft .

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