JP7184124B2 - Drive control device for electric vehicle - Google Patents

Description

The present invention relates to a drive control device for an electric vehicle such as an electric wheelchair having a differential gear mechanism.

2. Description of the Related Art Japanese Laid-Open Patent Publication No. 2002-100000 discloses an electric vehicle drive device that includes a differential gear mechanism that distributes the drive torque of an electric motor to drive wheels provided at both ends of a drive shaft.

JP 2004-236386 A

However, in the drive device for an electric vehicle disclosed in Patent Document 1, when one drive wheel is locked in a groove, the drive torque of the electric motor concentrates only on the other drive wheel. In such a state, when one driving wheel escapes from the groove and the other driving wheel in idling comes into contact with the road surface, the vehicle suddenly starts in a direction not intended by the driver. There is

SUMMARY OF THE INVENTION An object of the present invention is to stop the driving torque of the electric motor when the driving torque of the electric motor concentrates on one of the driving wheels, thereby preventing the vehicle from suddenly moving unintended by the driver. An object of the present invention is to provide a drive control device for an electric vehicle that can prevent the vehicle from starting.

A drive control device for an electric vehicle according to the present invention is a drive control device for an electric vehicle that travels by transmitting drive torque from an electric motor to a drive shaft and driving drive wheels provided at both ends of the drive shaft, wherein: A differential gear mechanism that distributes and transmits driving torque generated by an electric motor to each of the driving wheels , a braking device that brakes the driving wheels, a control section that controls the driving torque generated by the electric motor, and at least one end of the driving shaft. and a torque sensor installed on the side of the differential gear mechanism for detecting the driving torque distributed by the differential gear mechanism, and the control unit detects when the difference in the driving torque distributed by the differential gear mechanism exceeds a predetermined value. It is characterized in that the driving torque output by the electric motor is stopped at times, and the driving wheels are braked by the braking device.
Further, a drive control device for an electric vehicle according to the present invention is a drive control device for an electric vehicle that travels by transmitting drive torque from an electric motor to a drive shaft and driving drive wheels provided at both ends of the drive shaft. , a differential gear mechanism that distributes and transmits the driving torque of the electric motor to each of the driving wheels ; a braking device that brakes the driving wheels; a control unit that controls the driving torque of the electric motor; and a rotational speed detection unit installed on at least one end side of the drive shaft for detecting the rotational speed of at least one end side of the drive shaft. When the difference in the number of rotations between both ends of the shaft exceeds a predetermined value, output of the driving torque by the electric motor is stopped, and the braking device brakes the driving wheels. is.

According to the present invention, when one of the driving wheels gets stuck in a groove or mud, and the driving torque from the electric motor concentrates on one of the driving wheels and this driving wheel spins idle, the driving torque from the electric motor is controlled by the control unit. will be stopped. Therefore, it is possible to prevent a situation in which the idling drive wheels contact the ground, for example, and the vehicle starts suddenly against the driver's intention.

1 is a left side view of an electric vehicle to which a drive control apparatus for an electric vehicle according to a first embodiment of the invention is applied; FIG. FIG. 2 is a plan view showing the electric vehicle of FIG. 1; FIG. 3 is a cross-sectional view showing the gear unit of FIG. 2; FIG. 4 is a partially enlarged sectional view showing an enlarged part of FIG. 3; The disk member of FIG.3 and FIG.4 is shown, (A) is a front view, (B) is a side view. FIG. 3 is a block diagram showing the configuration of the drive control device for the electric vehicle shown in FIGS. 1 and 2; FIG. FIG. 2 is a block diagram showing the configuration of a second embodiment of a drive control device for an electric vehicle according to the present invention;

Hereinafter, embodiments for carrying out the present invention will be described based on the drawings.
(A) First embodiment (FIGS. 1 to 6)
FIG. 1 is a left side view of an electric vehicle to which a first embodiment of a drive control device for an electric vehicle according to the present invention is applied. 2 is a plan view showing the electric vehicle of FIG. 1. FIG. As shown in FIGS. 1 and 2, in an electric vehicle 10 such as a steering wheel type electric wheelchair, a pair of left and right front wheels 12 and rear wheels 13 are supported by a body frame 11 via suspensions (not shown). The vehicle body frame 11 is covered with a resin cover including a front cover 14, a leg shield 15, a floor panel 16, a rear cover 17, and the like, except for a portion thereof.

The substantially box-shaped rear cover 17 at the rear of the vehicle body projects upward, and the drive control device 20 and a battery (not shown) are accommodated inside the rear cover 17 . The drive control device 20, which will be described in detail later, transmits drive torque from an electric motor 18 as an electric motor to an axle 19 as a drive shaft via a gear unit 25, and drive wheels installed at both ends of the axle 19. The electric vehicle 10 is caused to run by driving the rear wheels 13 , and the driving torque of the electric motor 18 is controlled by the control section 21 .

A seat 22 on which the driver sits is mounted above the rear cover 17 via a bracket (not shown) rising from the vehicle body frame 11 . This seat 22 includes a seat cushion 23 and a seat back (backrest) 24 . Furthermore, armrests 26 are provided on both sides of the seat back 24 , and each armrest 26 is rotatably supported around a fulcrum 27 .

The leg shield 15 is arranged vertically in the front part of the vehicle body and protects the legs of the driver seated on the seat 22 from the wind. A steering shaft 29 for steering the front wheels 12 is erected inside the leg shield 15 , and a handle unit 30 is attached to the upper end of the steering shaft 29 . During normal steering, the driver sits on the seat 22 and rotates the steering wheel unit 30 to steer the front wheels 12 as steered wheels left and right.

The handle unit 30 has semicircular operation handles 32 projecting from both left and right sides of a switch box 31, and an accelerator lever 33 protruding from the switch box 31 and rotatably provided inside the operation handles 32. be done. The switch box 31 is provided with a power switch 34M, a maximum speed setting knob 34N, and the like.

The accelerator lever 33 extends in the width direction of the vehicle by bending in a crank shape to both sides from a rotation shaft portion 33A at the central portion in the axial direction, and has an operation portion 33B at both ends thereof. The control unit 21 controls the electric motor 18 based on the amount of depression when the driver of the electric vehicle 10 places his palm on the grip portion 32A of the operation handle 32 and pushes down the operation portion 33B of the accelerator lever 33 with his finger. As a result, the running speed of the electric vehicle 10 is controlled.

The drive control device 20 has the electric motor 18, the gear unit 25, the axle 19, and the control section 21 as described above, and further has the rotation speed detection units 40A and 40B (FIG. 3) and the notification section 50 (FIG. 6). It consists of Among them, the axle 19 has a left axle 19A with the left rear wheel 13A of the rear wheel 13 installed at the tip, and a right axle 19B with the right rear wheel 13B of the rear wheel 13 installed at the tip. Become. 3 and 4, the gear unit 25 is constructed by accommodating a reduction gear mechanism 37, a differential gear mechanism 38 and an electromagnetic brake 39 in casings 35 and 36 which are divided into left and right.

The electric motor 18 is bolted to the front left side surface of the casing 35 with its output shaft 41 extending in the vehicle width direction. An output shaft 41 of the electric motor 18 protrudes from the right end of the electric motor 18 and is connected to an input shaft 43 of the reduction gear mechanism 37 using a coupling member 42 so as to rotate integrally.

The reduction gear mechanism 37 includes the input shaft 43 provided concentrically with the output shaft 41 of the electric motor 18, an intermediate shaft 44 provided parallel to the input shaft 43, and a right end portion of the input shaft 43, which rotates integrally. a driven counter gear 46 provided at the left end of the intermediate shaft 44 and meshing with the drive pinion gear 45; and a slide gear provided on the intermediate shaft 44 adjacent to the driven counter gear 46. 47 and .

The input shaft 43 is rotatably supported by the casing 35 via bearings 48 and 49 . The intermediate shaft 44 is arranged behind the input shaft 43 and rotatably supported by the casings 35 and 36 via bearings 51 . The driven counter gear 46 is provided to rotate integrally with the intermediate shaft 44 by means of a mesh clutch 63 and a slide gear 47 which will be described later. Further, the slide gear 47 is spline-coupled with the intermediate shaft 44 so as to be slidable in the axial direction of the intermediate shaft 44 . This slide gear 47 meshes with the differential ring gear 52 of the differential gear mechanism 38 .

A driven counter gear 46 is provided with a larger diameter than the drive pinion gear 45 , and a differential ring gear 52 is provided with a larger diameter than the slide gear 47 . As a result, the driving torque generated by the electric motor 18 is reduced by the drive pinion gear 45, the driven counter gear 46, the slide gear 47 of the reduction gear mechanism 37 and the differential ring gear 52 of the differential gear mechanism 38, and the differential gear It is transmitted to mechanism 38 .

The differential gear mechanism 38 includes the differential ring gear 52 rotatably supported by the casing 35 via bearings 53 , and the differential gear mechanism 38 , for example, bolted to the differential ring gear 52 and rotatably supported by the casing 36 via bearings 54 . a differential case 55, a plurality of (for example, two) differential pinion gears 57 rotatably supported by a differential shaft 56 supported by the differential case 55, and differential side gears 58 and 59 meshing with the differential pinion gears 57. and

A differential side gear 58 and a differential side gear 59 are coupled to the base end of the left axle 19A and the right axle 19B so as to rotate integrally. When the drive torque from the electric motor 18 is transmitted to the differential ring gear 52 of the differential gear mechanism 38 through the reduction gear mechanism 37, the revolution and rotation of the differential pinion gear 57 causes the differential side gear 58 to be transmitted to the left axle 19A. 59 to be distributed and transmitted to the right axle 19B to drive the left rear wheel 13A and the right rear wheel 13B.

Here, the left axle 19A is accommodated in a left axle case 61 attached to the casing 35, and rotatably supported by the left axle case 61 via a bearing 60. As shown in FIG. The right axle 19B is accommodated in a right axle case 62 attached to the casing 36 and rotatably supported by the right axle case 62 via bearings 60 .

The electromagnetic brake 39 is arranged on the input shaft 43 so as to be positioned between the electric motor 18 and the reduction gear mechanism 37 . This electromagnetic brake 39 brakes the rotation of the input shaft 43 by cutting off the power supply to the electromagnetic coil (not shown) when the accelerator lever 33 (FIG. 2) is no longer pushed down, thereby controlling the left wheel. 13A and the right wheel 13B are braked and stopped.

A mesh clutch 63 is provided between the driven counter gear 46 and the slide gear 47 in the reduction gear mechanism 37 . The mesh clutch 63 is brought into a clutch-engaged state when the slide gear 47 is pressed against the driven counter gear 46 by the biasing force of the spring 64 , and transmits the rotational force of the driven counter gear 46 to the intermediate shaft 44 via the slide gear 47 . . When the slide gear 47 is separated from the driven counter gear 46 against the urging force of the spring 64 by a clutch operating mechanism (not shown), the dog clutch 63 is released. As a result, the rear wheels 13 (the left rear wheel 13A and the right rear wheel 13B) are brought into a rotation-free state, and the electric vehicle 10 can be manually pushed.

As shown in FIG. 3, the rotation speed detection unit 40A detects the rotation speed of the left axle 19A which is one end of the axle 19, and the rotation speed detection unit 40B detects the right axle which is the other end of the axle 19. As shown in FIG. 19B and includes a disk member 65 and a rotation speed detection sensor 66 . The disc member 65 of the rotation speed detection unit 40A is attached to the tip of the left axle 19A in the left axle case 61, and the disc member 65 of the rotation speed detection unit 40B is attached to the tip of the right axle 19B in the right axle case 62. , are provided separately or integrally (separately in this embodiment) to rotate integrally. The disk member 65 has a plurality of projections or notches, and in this embodiment, as shown in FIG.

3 and 4, the rotation speed detection sensor 66 of the rotation speed detection unit 40A is attached to the left axle case 61, and the rotation speed detection sensor 66 of the rotation speed detection unit 40B is attached to the right axle case 62 by mounting bolts 67. is used to face the projection 65A of the disk member 65. As shown in FIG. The rotation speed detection sensor 66 detects the number of projections 65A of the disc member 65 rotated by the left axle 19A and the right axle 19B detected within a certain period of time. The rotation speeds of the axle 19A and the right axle 19B are detected. As shown in FIG. 6, the rotation speed detection sensor 66 of the rotation speed detection unit 40A detects the detected rotation speed of the left axle 19A, and the rotation speed detection sensor 66 of the rotation speed detection unit 40B detects the detected rotation speed of the right axle 19B. are transmitted to the control unit 21 respectively.

The control unit 21 controls the drive torque generated by the electric motor 18 as described above. Specifically, the control unit 21 controls the drive distributed by the differential gear mechanism 38 based on the rotation speeds of the left axle 19A and the right axle 19B detected by the disk members 66 of the rotation speed detection units 40A and 40B. When the difference in rotational speed between both ends of the axle 19 (that is, the left axle 19A and the right axle 19B), which rotates due to torque, exceeds a predetermined value O, the electric motor 18 is stopped and the electric motor 18 outputs drive torque. is stopped, power supply to the electromagnetic brake 39 is cut off, and the electromagnetic brake 39 brakes the rear left wheel 13A and the rear right wheel 13B.

The predetermined value O is set to a value that allows detection of concentration of the driving torque of the electric motor 18 on either the left axle 19A or the right axle 19B. Specifically, the predetermined value O is detected by a maximum speed set value set by a maximum speed setting knob 34N provided in the switch box 31 of the handle unit 30 (FIG. 2) and a steering angle sensor (not shown). It is set in consideration of the steering angle of the steering shaft 29 (FIG. 1). For example, when the steering angle is zero degrees (straight driving), the predetermined value O is set to zero ±5%, and the control unit 21 sets the difference in rotation speed between the left axle 19A and the right axle 19B to zero ±5. %, the electric motor 18 is stopped and the electromagnetic brake 39 brakes the left rear wheel 13A and the right rear wheel 13B.

When an abnormality occurs in the electric vehicle 10, the notification unit 50 notifies the occurrence of the abnormality by voice or image display. When the electric motor 18 is stopped and the output of the drive torque from the electric motor 18 is stopped, the control unit 21 notifies the driver or surrounding people of the occurrence of the abnormality through the notification unit 50 .

Either one of the rotation speed detection units 40A and 40B may be installed. For example, when only the rotational speed detection unit 40A is installed and the rotational speed of the left axle 19A is detected by the rotational speed detection unit 40A, the controller 21 detects the rotational speed of the electric motor 18 and the rotational speed of the left axle 19A. , and the difference between the left axle 19A and the right axle 19B may be compared with a predetermined value O.

With the configuration as described above, according to the first embodiment, the following effects (1) to (3) are obtained.
(1) The control unit 21 that controls the driving torque of the electric motor 18 rotates the left axle 19A and the right axle 19B by the driving torque distributed to the left axle 19A and the right axle 19B by the differential gear mechanism 38. When the difference in the numbers exceeds a predetermined value O, the electric motor 18 is stopped to stop the output of drive torque from the electric motor 18, and the electromagnetic brake 39 brakes the left rear wheel 13A and the right rear wheel 13B. Let

Therefore, either the left rear wheel 13A or the right rear wheel 13B gets stuck in a ditch or mud, and the wheel 13 on the opposite side of the wheel 13 stuck in the groove or the wheel 13 stuck in the quagmire is powered. When the driving torque of the motor 18 concentrates and the rear wheel 13 spins idle, the controller 21 stops the electric motor 18 to stop the driving torque of the electric motor 18, and the electromagnetic brake 39 causes the left rear wheel 13A to rotate. and the right rear wheel 13B is braked. Therefore, it is possible to prevent a situation in which the idling rear wheel 13 touches the ground, causing the electric vehicle 10 to suddenly start against the driver's intention.

(2) When an abnormality occurs that stops the electric motor 18 and stops the output of the drive torque from the electric motor 18, the control unit 21 notifies the driver of the electric vehicle 10 and the surrounding area of the abnormality by the notification unit 50. It is configured to notify people. Therefore, the driver or the like of the electric vehicle 10 can quickly grasp the abnormality of the electric vehicle 10 in which the electric motor 18 stops as a result of the idling of either the left rear wheel 13A or the right rear wheel 13B.

(3) The rotation speed detection units 40A and 40B have the disk member 65 attached to each of the left axle 19A and right axle 19B, and the rotation speed detection sensor 66 attached to each of the left axle case 61 and right axle case 62. It consists of Therefore, since the rotation speed detection units 40A and 40B use existing parts (left axle 19A, right axle 19B, left axle case 61, right axle case 62), the number of parts can be reduced. As a result, the man-hours for assembling the rotation speed detection units 40A and 40B can be reduced, and assembly defects can be suppressed, so that the quality of the rotation speed detection units 40A and 40B can be improved.

[B] Second embodiment (Fig. 7)
FIG. 7 is a block diagram showing the configuration of a second embodiment of the drive control device for an electric vehicle according to the present invention. In the second embodiment, the same reference numerals as in the first embodiment are used for the same parts as in the first embodiment, so that the description is simplified or omitted.

The drive control device 70 of the second embodiment differs from the first embodiment in that, instead of the rotational speed detection units 40A and 40B of the first embodiment, a torque sensor 71A is provided on the left axle 19A and a torque sensor 71A is provided on the right axle 19B. Sensors 71B are installed respectively, and the controller 21 performs control to stop the output of the drive torque by the electric motor 18 based on the detected values from these torque sensors 71A and 71B.

That is, the torque sensor 71A detects the drive torque generated by the electric motor 18 and distributed to the left axle 19A by the differential gear mechanism 38. As shown in FIG. The torque sensor 71B detects the drive torque generated by the electric motor 18 and distributed to the right axle 19B by the differential gear mechanism 38. As shown in FIG. The driving torques detected by these torque sensors 71A and 71B are transmitted to the control section 21. FIG. The control unit 21 stops the electric motor 18 and stops the electric motor 18 when the difference between the driving torques of the left axle 19A and the right axle 19B detected by the torque sensors 71A and 71B exceeds a predetermined value P. stop the output of the drive torque, further cut off the power supply to the electromagnetic brake 39, and the electromagnetic brake 39 brakes the left rear wheel 13A and the right rear wheel 13B.

As with the predetermined value O, the predetermined value P is set to a value that allows detection of concentration of the driving torque of the electric motor 18 on either the left axle 19A or the right axle 19B. Either one of these torque sensors 71A and 71B may be installed. For example, when only the torque sensor 71A is installed and the driving torque distributed to the left axle 19A is detected by this torque sensor 71A, the controller 21 distributes the driving torque generated in the electric motor 18 and the left axle 19A. The drive torque distributed to the right axle 19B is calculated from the difference between the drive torque and the drive torque distributed to the left axle 19A and the drive torque distributed to the right axle 19B. good.

Due to the configuration as described above, the second embodiment also has the same effect as the effect (2) of the first embodiment, and also has the following effect (4).

(4) The control unit 21 that controls the driving torque of the electric motor 18 controls the electric motor 18 when the difference between the driving torques distributed to the left axle 19A and the right axle 19B by the differential gear mechanism 38 exceeds a predetermined value P. is stopped to stop the output of drive torque from the electric motor 18, and the electromagnetic brake 39 brakes the left wheel 13A and the right wheel 13B.

Therefore, either the left rear wheel 13A or the right rear wheel 13B gets stuck in a ditch or mud, and the wheel 13 on the opposite side of the wheel 13 stuck in the groove or the wheel 13 stuck in the quagmire is powered. When the driving torque of the motor 18 concentrates and the rear wheel 13 spins idle, the controller 21 stops the electric motor 18 to stop the driving torque of the electric motor 18, and the electromagnetic brake 39 causes the left rear wheel 13A to rotate. and the right rear wheel 13B is braked. Therefore, it is possible to prevent a situation in which the idling rear wheel 13 touches the ground, causing the electric vehicle 10 to suddenly start against the driver's intention.

Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention, and these replacements and changes can be made. is included in the scope and gist of the invention, and is included in the scope of the invention described in the claims and its equivalents.

For example, the control unit 21 manages the difference in the number of rotations of the left axle 19A and the right axle 19B, or the difference in the drive torque distributed to the left axle 19A and the right axle 19B, so that these differences ( It is also possible to detect uneven wear of the rear wheel 13 on one side (rear left wheel 13A or rear right wheel 13B) when the difference in rotational speed and drive torque exceeds a predetermined threshold.

In addition, the disk members 65 of the rotation speed detection units 40A and 40B of the first embodiment are installed inside the left rear wheel 13A and right rear wheel 13B, or installed in the differential side gears 58 and 59 of the differential gear mechanism 38, respectively. Alternatively, the number of rotations of each of the left axle 19A and the right axle 19B may be indirectly detected by a number of rotations detection sensor 66 installed at a position corresponding to the disk member 65. FIG.

DESCRIPTION OF SYMBOLS 10... Electric vehicle 13... Rear wheel (drive wheel) 13A... Left rear wheel 13B... Right rear wheel 18... Electric motor (electric motor) 19... Axle (drive shaft) 19A... Left axle 19B... Right Axle 20 Drive control device 21 Control unit 38 Differential gear mechanism 40A, 40B Revolution detection unit 50 Notification unit 61 Left axle case 62 Right axle case 65 Disc Members 66... Rotational speed detection sensor 70... Drive control device 71A, 71B... Torque sensor O, P... Predetermined value

Claims (3)

In a drive control device for an electric vehicle that travels by transmitting drive torque from an electric motor to a drive shaft and driving drive wheels provided at both ends of the drive shaft,
a differential gear mechanism that distributes and transmits the drive torque generated by the electric motor to each of the drive wheels ;
a braking device that brakes the driving wheels;
a control unit that controls the driving torque of the electric motor;
a torque sensor installed on at least one end side of the drive shaft and detecting the drive torque distributed by the differential gear mechanism;
The control unit is configured to stop output of the driving torque by the electric motor and brake the driving wheels by the braking device when a difference in driving torque distributed by the differential gear mechanism exceeds a predetermined value. A drive control device for an electric vehicle, characterized by: In a drive control device for an electric vehicle that travels by transmitting drive torque from an electric motor to a drive shaft and driving drive wheels provided at both ends of the drive shaft,
a differential gear mechanism that distributes and transmits the drive torque generated by the electric motor to each of the drive wheels ;
a braking device that brakes the driving wheels;
a control unit that controls the driving torque of the electric motor;
a rotational speed detection unit installed on at least one end side of the drive shaft for detecting the rotational speed of at least one end side of the drive shaft;
The control unit causes the electric motor to stop outputting the drive torque when the difference in the number of rotations between both ends of the drive shaft rotated by the drive torque distributed by the differential gear mechanism exceeds a predetermined value. 1. A drive control device for an electric vehicle, wherein said braking device brakes said driving wheels. A notification unit for notifying an abnormality of the electric vehicle is provided, and the control unit is configured to notify the occurrence of the abnormality by the notification unit when an abnormality occurs that stops the output of the driving torque by the electric motor. 3. The drive control device for an electric vehicle according to claim 1 or 2.

Images