JPH07285422A - Electric vehicle - Google Patents

Abstract

PURPOSE:To prevent the breakage of a driving system including a parking mechanism when the parking mechanism of an electric vehicle starts operation when the vehicle is still in movement. CONSTITUTION:As for a driving system which is constituted so that the output of a motor 10 is decelerated by a reduction gear 14, and transmitted to a driving shaft 60, and the joined driving wheel is driven, a parking mechanism 12 is arranged between the motor 10 and the reduction gear 14, a buffering mechanism is arranged between the parking mechanism 12 and the motor 10. The buffering mechanism is installed. The buffering mechanism is equipped with a hollow-shaped output shaft 24 fixed with the rotor 22 of the motor 10 and a torsional shaft 30 which penetrate through the inside of the output shaft and whose one end is connected with the output shaft 24 and the other end is connected with the parking mechanism 12. If the parking lock operation is carried out during the movement of the vehicle, the inertia of the rotor 22 is absorbed by the torsional shaft 30, and the occurrence of the shocking stress is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle, and more particularly to the structure of a drive shaft of an electric vehicle having a parking mechanism for fixing the movement of the vehicle during parking.

[0002]

2. Description of the Related Art Electric vehicles have hitherto been used in limited applications because they do not emit exhaust gas and have a low running noise. For example, it has been used for carrying luggage indoors, delivering in the early morning, and in unusual places for leading vehicles such as marathons. On the other hand, most current automobiles are driven by an internal combustion engine that uses hydrocarbons such as gasoline and light oil as fuel, and emit carbon dioxide and nitrogen oxides into the atmosphere. In order to reduce the total amount of these exhaust gases, there is an increasing demand for wider use of electric vehicles.

An electric vehicle runs by driving drive wheels with an electric motor. The output (torque) characteristic of an electric motor is
At present, there is a characteristic that torque in a low speed range is large as compared with a reciprocating type internal combustion engine which is most popular as a vehicle drive engine. Therefore, it is not necessary to provide the electric vehicle with a transmission device such as a multi-stage transmission mechanism, a clutch mechanism, and a torque converter, which are provided in a vehicle driven by an internal combustion engine. Therefore, the output of the drive electric motor is transmitted to the drive wheels via the single-stage speed reducer, the differential mechanism, the drive shaft, and the like. Therefore, the drive system of the electric vehicle does not have a frictional transmission element such as a clutch or a fluid transmission element such as a torque converter, and thus the motor and the drive wheels are in a substantially direct connection state.

Further, although an electric vehicle is equipped with a side brake which is provided in a normal vehicle, engine braking cannot be expected. Therefore, like an automatic transmission vehicle, the rotational resistance of the engine when stopped is used. Since there is no such braking mechanism, a mechanical parking mechanism is provided. This parking mechanism is a mechanism for fixing rotation of a drive shaft by engaging a parking lock gear fixed to a drive shaft with a parking lock claw fixed to a gear case or the like. In general, this mechanism is a mechanism that prevents the vehicle from moving due to an inclination of the parking place because the side brake is not very effective during parking.

[0005]

As described above, in the drive system of an electric vehicle, the motor and the drive wheels are in a substantially completely connected state. For this reason, when the parking mechanism described above is provided, if the parking mechanism is activated while the vehicle is still moving, a large impact is applied to the drive system, and this impact causes damage to the weakest part. It was

Japanese Patent Laid-Open No. 527848/1993 discloses a device in which a parking lock gear is provided in a high-strength differential case so as to withstand this impact. However, the parking mechanism cannot be provided in the differential mechanism, such as when the reduction gear is arranged between the motor and the differential mechanism. Further, even if the strength of the parking lock gear portion is simply increased, stress concentrates on the other portion having low strength and the portion is damaged, so that it is not a fundamental solution to the above problems.

The present invention has been made to solve the above-mentioned problems, and an electric vehicle in which the drive system is not damaged by an impact generated when the parking device is operated while the vehicle is moving. The purpose is to provide.

[0008]

In order to achieve the above-mentioned object, an electric vehicle according to the present invention is provided on a drive shaft connecting a motor and drive wheels, and engages with a parking lock pawl to drive the drive shaft. A parking lock gear for fixing the rotation of the motor and a shock absorbing means provided on a drive shaft between the motor and the parking lock gear for absorbing a shock in a rotating direction.

Further, shock absorbing means for absorbing the shock in the rotating direction is fixed to the rotor side of the motor, penetrates the hollow motor output shaft and the hollow portion of the motor output shaft, and the motor output shaft. And a torsion shaft connected at one end and connected to the parking gear at the other end.

[0010]

The present invention has the above-mentioned structure, and the impact applied to the drive system can be relaxed by providing the drive system with the shock absorbing means. In particular, by arranging the buffering means between the rotor of the motor and the parking lock gear, a more effective buffering action against a shock due to the rotor inertial force of the motor having a larger inertia is exhibited.

Further, since the output shaft of the motor is a hollow shaft and the torsion shaft is arranged inside the output shaft, the device can be made compact. In particular, it is suitable for shortening the dimension in the output shaft direction.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a motor 10 and a parking mechanism 1.
2 shows a schematic configuration of a power plant of an electric vehicle including the two and the speed reducer 14. A stator 18 is fixedly arranged in the motor case 16 of the motor 10. By the predetermined alternating current flowing through the coil of the stator 18,
A rotating magnetic field is generated. A rotor 22 around which a permanent magnet 20 is provided is arranged inside the stator 18.
A motor output shaft 24 is fixed through the center of the rotor 22, and both ends of the output shaft 24 are sealed with the spherical bearing 2.
The motor case 16 is rotatably supported by the motors 6 and 28. The output shaft 24 has a hollow cylindrical shape, and a spline 24a is formed on the inner surface of the cylinder at the left end in the figure.

Inside the hollow cylinder of the output shaft 24, a torsion shaft 30 is arranged coaxially with the output shaft 24 so as to penetrate therethrough. Then, at the left end of the torsion shaft 30, the spline 3 is provided on the outer periphery thereof.
0a is provided, which meshes with the spline 24a on the inner surface of the output shaft cylinder. Therefore, the output shaft 24
And the torsion shaft 30 are coupled to each other and integrally rotate. A spline 30b is provided at the right end of the torsion shaft 30, and the rotation of the motor 10 is output from this.

As described above, the motor 10 of this apparatus basically adopts the structure of a permanent magnet type synchronous motor, and the output thereof is taken out from the right end portion of the torsion shaft 30 via the output shaft 24.

At the right end of the torsion shaft 30, a spline 32 having a cylindrical joint 32 is provided on the inner surface of the cylinder.
The a and the spline 30b of the torsion shaft are engaged with each other to be coupled. This joint is further extended in the right direction in the drawing from the portion that meshes with the spline 30b of the torsion shaft, and the spline 3 of the intermediate shaft 34 is extended at this extended portion.
4a is inserted and joined. The intermediate shaft 34 is rotatably supported by partition walls 42 and 44 inside the reduction gear case 40 via ball bearings 36 and 38.

A parking mechanism 1 is provided between the partition walls 42 and 44.
Two are provided. A spline 34b is provided in a portion of the intermediate shaft 34 located between the partition walls 42 and 44, and a parking lock gear 46 is coupled to the spline 34b. Therefore, the parking lock gear 46 rotates integrally with the intermediate shaft 34. That is, the rotor 2
2, the output shaft 24, the torsion shaft 30, the intermediate shaft 34, and the parking lock gear 46 rotate integrally. In addition, substantially rectangular lock ridges 46a are arranged at a predetermined interval on the outer peripheral portion of the parking lock gear 46. The parking mechanism 12 further includes a parking lock pawl 48 having a parking lock pawl 48a, and by engaging the parking lock pawl 48a and the lock crest 46a, a series of output shaft systems can be fixed so as not to rotate. The parking mechanism 12 described above will be described in detail later.

The intermediate shaft 34 is further extended to the speed reducer 14 having a planetary gear mechanism in the right direction in the figure, and the sun gear 5 of the speed reducer 14 is provided on a spline 34c provided in the extended portion.
Combined with 0. The sun gear 50 is rotatably supported by a planet shaft 52 fixed to the partition wall 42, and meshes with a planet gear 54 arranged around the sun gear, and the planet gear 54 further meshes with a ring gear 56 around the planet gear 54. ing. In this way, the speed reduction mechanism of the present device is configured so that the planetary gear shaft 5
2 is a fixed element, the sun gear 50 is an input element, and the ring gear 56 is an output element, which is a general planetary gear mechanism.

The output of the motor 10 is transmitted to the drive shaft 60 via the drive plate 58 fixed to the ring gear 56 of the speed reducer 14. Drive wheels (not shown) are connected to the drive shaft, so that the vehicle body is driven by the motor 10.

The details of the parking mechanism 12 are shown in FIG. FIG. 2 shows a side view of the parking mechanism shown in FIG. The parking lock gear 46 is fixed to the intermediate shaft 30 and rotates integrally with the intermediate shaft 30. On the outer periphery of the parking lock gear 46, there are four lock mountains.
6a are arranged at a predetermined pitch, and a parking pole 48 having a parking lock claw 48a is arranged at a position where it can mesh with the lock mountain.

The parking lock pole 48 is a pole shaft 6
It is rotatably supported at 0, and by rotating around this axis, the lock mountain 46a and the parking lock claw 48a are engaged and disengaged. Also, parking lock pole 48
Is urged clockwise by a return spring 62 in the figure. That is, the parking lock pole 48
Is biased away from the parking lock gear 46. A cam follower 48b is provided at the other end of the rotation shaft (pole shaft 60) of the parking lock pole 48, and engages with a lock cam 64 described later to control the rotation position of the parking lock pole 48.

The lock cam 64 is provided on the rod 66, and its shape has a small diameter portion 64a having a diameter slightly larger than that of the rod 66 and a large diameter portion 64b having a diameter larger than that. One end of the rod 66 is rotatably connected to the detent plate 68, and moves substantially in the left-right direction in response to the rotation of the detent plate 68 about the axis 70. By moving the rod 66 in the left-right direction, the contact position between the cam follower 48b and the cam 64 is changed to control the rotating position of the parking lock pole 48 to control the parking mechanism 12. That is, the release position of the parking mechanism 12 during normal traveling is set to the cam small diameter portion 64a.
And the cam follower 48b are engaged with each other, and the parking lock pole 48 is controlled to a position away from the parking lock gear 46.
6a is separated. In addition, the parking mechanism 1
The operating position of 2 is the cam large diameter portion 64b and the cam follower 48.
It is a position where b is engaged, and the parking lock pole 4
8 is controlled to a position close to the parking lock gear 46 so that the lock claw 48a and the lock crest 46a are engaged with each other. The intermediate shaft 30 is fixed in a state where the lock claw 48a and the lock crest 46a are engaged with each other, and the output shaft 24 and the torsion shaft 30 connected to the intermediate shaft 30 are fixed.
And the drive shaft 60 is fixed.

The above-described control of the parking mechanism 12 is performed by the driver of the vehicle by a shift lever provided near the driver's seat in the passenger compartment. By operating the shift lever, the detent plate 68 connected to the shift lever by a wire rotates. When locking the parking lock, the driver sets the shift lever to the parking position. In response to the movement of this shift lever, the detent plate 6
8 moves counterclockwise in FIG. 2, and further, the rod 66 moves leftward. Then, the cam large diameter portion 64b is fixed to the fixing pin 72.
Between the cam follower 48b and the cam follower 4b.
8 is rotated counterclockwise so that the lock claw 48a and the lock crest 46a are in mesh with each other.

If the above parking lock operation is performed in a state where the vehicle is not completely stopped, the rotations of the parking lock plate 46 and the intermediate shaft 34 suddenly stop. The shaft 30, the output shaft 24, and the rotor 22 try to continue rotating due to inertia. Due to this inertia, a shocking stress is generated in the shaft system. This stress is concentrated in the weakest part of this shaft system,
In the worst case, this weak part may be damaged. Therefore, the present device has a mechanism for buffering the shock in order to reduce the peak value of the shocking stress, which corresponds to a part of the torsion shaft 30 and the output shaft 24. As described above, when the parking lock is activated while the vehicle is still in motion, the parking lock gear 46 and the intermediate shaft 34 suddenly stop rotating, but the rotor 22 tries to continue rotating due to inertia. Due to this rotation difference, the portion of the output shaft 24 protruding to the left of the rotor 22 in FIG.
0 is twisted. By this action, the shock is absorbed, the generation of stress is dispersed over time, and the peak value is lowered. Therefore, in the shaft system described above, it is not necessary to adopt a structure corresponding to the peak value of shocking stress when there is no buffer mechanism.

Further, in the present apparatus, the buffer mechanism is provided between the parking mechanism 12 and the rotor 22 because the inertia which the drive shaft 60 side, that is, the vehicle body generally has, and the rotor 22.
When the inertias of the rotors 22 are compared, the inertia of the rotor 22 is larger, and the peak value of the stress is the parking mechanism 12 or the rotor 22.
It is based on the idea that it occurs somewhere in the axis system that connects this and the parking mechanism. Further, since the input from the drive shaft 60 is input to the parking mechanism 12 via the speed reducer 14,
Based on the judgment that the torque becomes smaller and smaller, it is sufficient to consider only the input from the rotor 22 side.

Further, with respect to the arrangement of the parking mechanism 12, in this device, it is arranged between the speed reducer 14 and the rotor 22. When this is installed after the speed reducer 14,
The inertial force of the rotor 22 is amplified by the speed reducer 14 and is applied to the parking mechanism 12, so that the parking mechanism 1
This is to avoid the need to increase the strength of 2.

As described above, in the present device, when the parking operation is performed while the vehicle is still moving, the stress generated by the buffer mechanism such as the torsion shaft 30 is dispersed in terms of time to reduce the stress. The peak value can be reduced. In other words, the inertial energy is temporarily stored in the buffer mechanism and gradually released to prevent temporal concentration of stress. As a result, the maximum stress value can be reduced, and when the parking lock operation is accidentally performed while the vehicle is still in motion, the parking lock claw 48a, the lock crest 46a, etc. of the parking mechanism 12 and the drive shaft system. Can be prevented from being damaged. Further, according to this embodiment, the permanent magnet fixed to the outer circumference of the rotor is less likely to be peeled off or damaged due to the impact at the time of parking lock, so that the performance can be secured for a long time.

In this embodiment, a preferred embodiment has been described by taking a torsion type shock absorbing mechanism using a torsion shaft as a shock absorbing mechanism, but the present invention is not limited to this, and a friction clutch is used, for example. The same effect can be obtained by using a sliding type cushioning mechanism.

Further, the same effect can be obtained by using a spring type cushioning mechanism in which coil springs are arranged in the circumferential direction.

[0030]

According to the present invention having the above-mentioned structure, the impact applied to the drive system can be relaxed by providing the drive system with the torsional shock absorbing means. Therefore, even if the parking lock operation is performed while the vehicle is still moving, it is possible to prevent damage to the drive system such as the parking lock gear and the lock claw or the rotor.

In particular, by arranging the buffering means between the motor and the parking lock gear, a more effective buffering action against a shock by the rotor of the motor having a larger inertia is exhibited. This buffering effect makes it possible to reduce the maximum value of stress. In other words, the required strength of the member is reduced, a lighter structure can be realized, and the overall weight and size of the device can be reduced.

Furthermore, by making the output shaft of the motor a hollow shaft and disposing the torsion shaft inside the output shaft, a device with good space utilization efficiency can be constructed. That is, downsizing of the device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a preferred embodiment of a power plant of an electric vehicle according to the present invention.

FIG. 2 is a detailed view of a parking mechanism of this embodiment.

[Explanation of symbols]

 10 Motor 12 Parking Mechanism 14 Reducer 22 Rotor 24 Output Shaft 30 Torsion Shaft 34 Intermediate Shaft 46 Parking Lock Gear 46a Lock Mountain 48 Parking Lock Pole 48a Parking Lock Claw

Claims (2)

[Claims] 1. In an electric vehicle that drives a drive wheel by a motor to travel, the rotation of the drive shaft is fixed by being provided on a drive shaft connecting the motor and the drive wheel and engaging with a parking lock pawl. An electric vehicle comprising: a parking lock gear; and a shock absorbing means provided on a drive shaft between the motor and the parking lock gear, for absorbing a shock in a rotational direction. 2. The electric vehicle according to claim 1, wherein the shock-absorbing means for shock-absorbing in the rotation direction is fixed to the rotor side of the motor, has a hollow motor output shaft, and a hollow portion of the motor output shaft. And a torsion shaft which is connected to the motor output shaft at one end and is connected to the parking lock gear at the other end.