JPH1024812A - Brake structure for electric motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to, in an electric motor vehicle, use one brake means, brake both right and left rear wheels with a small braking torque, and install the brake means without a substantial design change of an existing electric motor vehicle. SOLUTION: In a brake structure for an electric motor vehicle, which is equipped with a pair of right and left rear wheels to be interlocked via a differential gear 24 and a driving motor driving the right and left rear wheels, a clutch means which consists of an internal-toothed dog 30a and a slide gear 32, and intermits the power transmission route is provided in the power transmission route from the driving motor to the differential gear, and a brake drum 52 which brakes the right and left wheels irrespective of the condition of engagement/disengagement of the slide gear 32 and the internal-toothed dog 30a is disposed on the route coaxially to a counter shaft 26 which is nearer to the driving motor than to be differential gear.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake structure for an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, three-wheel or four-wheel electric vehicles using an electric motor as a drive source have been widely used. Generally, an electric vehicle is equipped with a drive unit mainly including a drive motor, a gear transmission, and a gear case, and the drive unit drives a pair of left and right rear wheels.
Normally, the axles of the left and right rear wheels are interlocked via a differential device.

[0003]

By the way, when the conventional electric vehicle is provided with a brake for rear wheel braking,
It is conceivable to arrange a brake drum, which is operated by operating a lever provided on the steering wheel, on the rear wheel.

However, when the brake drum is provided on the rear wheel itself, the brake drum is required for each of the left and right rear wheels, which increases the cost. At the same time, since a large braking torque is required for the brake drum, each brake drum becomes large. When the electric vehicle is provided with a brake, it is preferable that the brake can be used regardless of the ON / OFF state of the clutch means provided in the power transmission path of the drive system. When a brake is provided, it is desired that existing components of the electric vehicle, particularly components of the drive unit, can be shared as much as possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to brake both left and right rear wheels with a single braking means and with a small braking torque. It is an object of the present invention to provide a brake structure for an electric vehicle that can be installed without a significant design change.

[0006]

The present invention has the following configuration to achieve the above object. That is, the invention according to claim 1 is an electric vehicle including a pair of left and right rear wheels interlocked via a differential device, and a drive motor for driving the left and right rear wheels. A clutch means for connecting / disconnecting the power transmission path to a power transmission path to a moving device, and a brake means capable of braking the right and left rear wheels regardless of the on / off state of the clutch means; A brake structure for an electric vehicle, wherein the brake structure is disposed closer to the drive motor.

According to a second aspect of the present invention, the left and right gear cases support a counter shaft, a counter gear driven by the drive motor is provided on the counter shaft, and the power transmission path includes the counter gear and the counter gear. A slide gear that is provided on the shaft so as to be slidable in the axial direction and engages and disengages with the counter gear to intermittently transmit power, and a final gear that is provided on the differential so as to always mesh with the slide gear. The slide gear is provided with a cylindrical portion at an end of the slide gear opposite to the counter gear, and always engages with the outer peripheral portion of the cylindrical portion in the rotational direction and controls the axial movement of the cylindrical portion. A coil spring for rotatably providing a brake shaft having an engagement hole capable of being absorbed to the counter shaft, and for urging the slide gear in a direction for engaging the counter gear; And a brake drum attached to an end of the brake shaft opposite to the engaging hole, the fitting being fitted to the counter shaft inside the cylindrical portion and the engaging hole. It is a brake structure of the electric vehicle of description.

According to a third aspect of the present invention, a ball bearing and an oil seal provided in the gear case on the brake shaft side are fitted to a position on the outer peripheral portion of the brake shaft and overlapping the engagement hole in the axial direction. The brake structure for an electric vehicle according to claim 2, wherein:

According to the first aspect of the present invention, since the brake means is provided in front of the differential device (on the side of the drive motor) in the power transmission path, both the right and left rear wheels can be braked by one brake means. . Further, since the rear wheel can be braked by the brake means regardless of the engaged / disengaged state (ON / OFF) of the clutch, the rear wheel can be braked even when the vehicle is manually pushed due to a dead battery or the like.

According to the second aspect of the invention, the braking force of the brake drum is transmitted to both left and right rear wheels via the brake shaft, slide gear, final gear, and differential. Therefore, both the left and right rear wheels can be braked by one brake drum, and at the same time, the rear wheels can be braked regardless of the engagement / disengagement state of the slide gear with respect to the counter shaft.

According to the third aspect of the present invention, the ball bearing and the oil seal are located radially outside the engagement hole for absorbing the movement of the slide gear. It can be arranged in the direction inside (the parts are overlapped). Therefore, even if the brake drum is arranged coaxially with the counter shaft, the entire width of the left and right gear cases can be set to the same size as the width of the existing electric vehicle, so that the body frame close to the gear case can be released. This eliminates the need for design changes. In addition, according to the third aspect of the present invention, the brake shaft and the brake drum are arranged on the counter shaft opposite to the counter gear with the slide gear interposed therebetween. Can be diverted from conventional products. Therefore, it is possible to equip the existing electric vehicle with a brake for rear wheel braking without making a significant design change.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the electric vehicle according to the present embodiment has two front wheels 2 and two rear wheels 4. The vehicle body mainly includes a front body A at the front and a rear body B at the rear. The driver drives the vehicle by sitting alone on the single seat 6. A front wheel steering handle 8 is provided at a position substantially above the center of the left and right front wheels 2 at the front of the vehicle body of the electric vehicle, and a front leg shield 10 is provided on a front body A below the handle 8. It is standing. In the front body A, a flat floor 12, which is a footrest, is formed at the center of the vehicle body from the rear side of the front leg shield 10 to the rear.

As shown in FIG. 1, the rear body B is located substantially rearward from the floor 12, and is substantially box-shaped as a whole. The rear body B accommodates a battery (not shown) at the front, and includes a drive motor 14 for the rear wheel 4 and a drive unit 18 (mainly composed of left and right gear cases 16L and 16R fastened by bolts 16a). 2 and 3) at the rear. Case structure 2
0, the cover 2 of the battery storage section is detachably mounted.
0a is provided, and a rear fender 22 protruding laterally so as to cover the rear wheel 4 is smoothly and continuously protruded from both left and right sides of a rear portion of the structure 20. Structure 20
The seat 6 is disposed on the upper side, and the back surface of the backrest 6 a of the seat 6 is located on substantially the same vertical plane as the rear wall of the case structure 20.

Next, the internal configuration of the drive unit 18 including the brake structure of the present embodiment will be described mainly with reference to FIGS. The drive unit 18 is disposed on the right side in the rear part of the case structure 20, and is fixed to a predetermined body frame by bolts or the like. Drive unit 1
A differential device 24 that connects the axles 4a of the left and right rear wheels 4 and allows relative movement of the left and right rear wheels 4 is provided in the internal space of the rear part of the gear cases 16L and 16R that mainly constitutes the rear wheel 8. The differential device 24 includes a pair of left and right large bevel gears 24a screwed to the inner ends of the left and right axles 4a, a pair of front and rear small bevel gears 24c meshing with the left and right large bevel gears 24a and supported by the shaft 24b. A housing 24d that supports both ends of the shaft 24b and the right large bevel gear 24a, and a housing 24d that is bolted 24e.
And a left and right gear case 16 fixed to the left side and rotating integrally with the left large bevel gear 24a.
It is mainly composed of a boss portion of the final gear 24f and a ball bearing 24g that supports the outer periphery of the right end of the housing 24d.

A counter shaft 26 is rotatably provided at the front of the left and right gear cases 16L and 16R. A left end of the counter shaft 26 has a ball bearing 28 press-fitted and fixed to the left gear case 16L. Supported by A counter gear 30 press-fitted into the counter shaft 26 is adjacent to the inside of the ball bearing 28, and the counter gear 30 is driven by a pinion (not shown) provided on the output shaft of the drive motor 14. .

A power transmission path from the drive motor 14 to the differential 24 is provided on the counter gear 30 and on a counter shaft 26 so as to be slidable in the axial direction, and is engaged with and disengaged from the counter gear 30. The slide gear 32 is configured to intermittently transmit power, and the final gear 24f is always meshed with the slide gear 32.

As shown in FIGS. 4 and 5, the slide gear 32 is formed by integrally forming a left gear portion 32a and a right cylindrical portion 32b via a small-diameter step portion 32c.
The left end of the gear portion 32a is capable of engaging and disengaging with an internal dog 30a formed on the right end surface of the counter gear 30. A spline 32b1 that is always engaged with a brake shaft described later is formed on the outer periphery of the cylindrical portion 32b.

The small diameter step 32c of the slide gear 32
As shown in FIG. 3, the shift fork 34 is sandwiched by the tip end thereof, and the base of the shift fork 34 is slidably slidable on a clutch shaft 36 rotatably supported on the front upper portions of the gear cases 16L and 16R. Axle-mounted. A shift cam 38 that is in pressure contact with the follower portion of the shift fork 34 is fixed to the clutch shaft 36, and a clutch lever 40 operated by a driver or the like is fastened to the right end of the clutch shaft 36 with a bolt 40a. ing. The clutch lever 40 indicated by a solid line in FIG.
2 shows the ON state of the clutch in which the gear portion 32a is fitted into the internal gear dog 30a. When the clutch lever 40 is tilted forward from this state to the position shown by the imaginary line in FIG. Moves rightward on the clutch shaft 36, the gear portion 32a of the slide gear 32 is completely disengaged from the internal gear dog 30a, and the OFF state of the clutch with the power transmission path interrupted is obtained.

As shown in FIG. 4, a brake shaft 42 is loosely and rotatably fitted to the right end of the counter shaft 26. As shown in FIG. 6, the brake shaft 42 includes a joint 42a having an inner peripheral surface having a spline 42a1 corresponding to the spline 32b1 of the slide gear 32,
The right end of the spline 42a1 is press-fitted and fixed to the shaft 42b. In the assembled state of the joint portion 42a and the shaft portion 42b, an engagement hole 42c is formed in the brake shaft 42 so as to be open to the slide gear 32 side and always engage with the outer peripheral portion (spline 32b1) of the cylindrical portion 32b. . The engaging hole 42c is connected to the moving cylindrical portion 32b.
And the depth thereof (the distance from the left end surface of the joint portion 42a to the left end surface of the shaft portion 42b) is set to be equal to or more than the movement amount of the slide gear 32, and the movement of the slide gear 32 It can be absorbed in the mating hole 42c.

As shown in FIG. 6, the shaft portion 42b has a bearing hole 42 for supporting the right end of the counter shaft 26 in a loosely fitted state.
b1. On the right side opposite to the bearing hole 42b1,
Step portion (breadth width) 42b2 having a rectangular cross section and step portion 42
A male screw portion 42b3 protruding rightward from b2 is provided.

As shown in FIG. 4, a coil spring 44 for urging the slide gear 32 in the direction of engagement with the counter gear 30 is fitted on the counter shaft 26 inside the cylindrical portion 32b and the engagement hole 42c. ing. The left end of the coil spring 44 abuts a step surface in the cylindrical portion 32b of the slide gear 32, and the right end is locked by a thrust washer 46 provided on the counter shaft 26 near the left end of the shaft portion 42b. .

As shown in FIG. 4, a ball provided in the gear case on the brake shaft 42 side, that is, the right gear case 16R, is located on the outer peripheral portion of the brake shaft 42 and overlaps the engaging hole 42c in the axial direction. The bearing 48 and the oil seal 50 are fitted. The step portion 42b2 and the male screw portion 42b3 of the brake shaft 42 project outside the right gear case 16R. Counter axis 2
The right end of 6 is stably supported by a ball bearing 48 via a brake shaft 42.

FIG. 4 shows a step 42b2 of the brake shaft 42.
As shown in FIG. 7, a substantially rectangular fitting hole 52a at the center of the brake drum 52 is fitted, and a nut 54 is screwed into the male screw portion 42b3 of the brake shaft 42. 42 and is integrally fixed.

As shown in FIGS. 4 and 8, a brake panel 56 is fastened to the outer surface of the right gear case 16R so as to include the brake drum 52 by bolts 58. An annular protruding edge 56a is provided at an edge of one side of the brake panel 56. By fitting the protruding edge 56a into an annular groove 16R1 provided on the outer surface of the gear case 16R, the brake panel 56 The positioning can be performed easily and accurately with respect to the gear case 16R.

At the front of the inside of the brake panel 56, FIG.
As shown in FIG. 8 and FIG. 8, a support pin 60 is protruded toward the internal space of the brake drum 52. As shown in FIG. The front end of the brake shoe 62 is rotatably mounted. A pair of upper and lower brake shoes 62
Is constantly urged inward by a pair of front and rear tension coil springs 62a.

As shown in FIGS. 2 and 9, a cam pin 64 is rotatably supported at the rear of the brake panel 56. A cam portion 64a at the tip of the cam pin 64 has
The rear ends of the upper and lower brake shoes 62 are fitted from above and below. As shown in FIGS. 4 and 9, one end of a brake lever 66 is fixed to the end of the cam pin 64 protruding to the outside of the brake panel 56, and the other end of the brake lever 66 is connected to the end shown in FIG. As shown, an operation rod 68 connected to the rear end of a brake wire (not shown) and inserted through the holding portion 56b of the brake panel 56 is attached via a pin 70 and a nut 72. A bellows-like cover 74 and a return spring (not shown) are interposed between the holding portion 56b of the brake panel 56 and the pin 70. The brake wire is connected from an operation rod 68 at the rear of the vehicle body to a lever provided on the right side of the handle 8. When the driver grips the lever and pulls the operating rod 68, the cam pin 64 rotates via the brake lever 66, and the upper and lower brake shoes 62 are spread in a direction away from each other by the cam portion 64a. As a result, the lining 62b of the brake shoe 62 is pressed against the inner peripheral surface of the brake drum 52, and a braking force is applied to the rotating brake shaft 42.

According to the present embodiment having the above-described configuration, the drum brake is provided in front of the differential device 24 in the power transmission path (on the drive motor 14 side of the final gear 24f). The wheel 4 can be braked by one drum brake. That is, the braking force on one brake drum 52 generated when the driver grips the lever is determined by the spline 42a2 of the four-sided width of the brake shaft 42, the spline 42a1 of the engagement hole 42c, and the spline of the cylinder 32b of the slide gear 32. Through 32b1, the gear portion 32a of the slide gear 32, the final gear 24f, and the components of the differential device 24, the power is transmitted to the left and right axles 4a and transmitted to both the left and right rear wheels 4. Further, the braking torque required for the brake drum 52 and the like can be very small as compared with the case where the brake means is provided on the rear wheel 4 itself, which is advantageous for reducing the size and weight of the electric vehicle.

Further, since the brake drum 52 is provided after the clutch means (the gear portion 32a of the slide gear 32 and the internal gear dog 30a of the counter gear 30) in the power transmission path, the rear wheel is provided regardless of the ON / OFF state of the clutch. 4 can be braked. Therefore, even when the driver or the like manually pushes the electric vehicle, the driver can grip the lever of the steering wheel 8 to apply a brake to the rear wheel 4.

Since the ball bearing 48 and the oil seal 50 are located outside the engagement hole 42c for absorbing the movement of the slide gear 32, the components (the brake shaft 42, the brake drum 42, 52, the brake panel 56, the brake lever 66, etc.) can be arranged to be packed inward in the axial direction. Therefore, even if a drum brake is added coaxially with the counter shaft 26,
The entire width of the drive unit 18 can be set to the same size as the width of the existing electric vehicle, whereby design changes such as releasing the body frame 76 (see FIGS. 2 and 3) close to the gear case 16R to the outside. Is no longer necessary. At the same time, the brake shaft 42 and the brake drum 52 are provided on the opposite side of the slide gear 32 from the counter gear 30, so that the existing parts of the counter gear 30 and the left gear case 16L are used as they are. can do. Therefore, a brake for rear wheel braking can be provided without making a significant design change to the existing electric vehicle.

FIG. 10 shows a structure around a counter shaft 26 in a conventional electric vehicle, and does not include a brake for rear wheel braking. When a drum brake is provided for such a structure, if the brake drum is mounted on the counter shaft 26 and on the right side of the coil spring 44 and the ball bearing 48 (the right end of the counter shaft 26), the brake on the outside of the brake drum The panel protrudes greatly outward. That is, the slide gear 32, the moving distance of the slide gear 32, the coil spring 44, the ball bearing 48, the oil seal, the brake drum, the brake panel, and the brake lever are connected in series. The gear case 16L has to be changed. On the other hand, in the present embodiment, the engagement hole 42c for releasing the slide gear 32 is formed, the coil spring 44 is stored in the engagement hole 42c and the like, and the slide gear 32 and the ball belling 48 Due to the unique configuration such as the superposition with the oil seal 50, the entire width of the drive unit 18 including the brake lever 66 is kept within the same size as the conventional one, so that peripheral parts such as the body frame 76 are not affected. The effect is obtained.

This embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment.

[0032]

As described above, according to the present invention, in an electric vehicle, both the left and right rear wheels can be braked with a single braking means and with a small braking torque, and the electric vehicle can be greatly reduced. It is possible to equip the brake means without making any major design changes.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electric vehicle according to an embodiment.

FIG. 2 is a side view of the structure around the gear case according to the embodiment, as viewed from the right side in the vehicle traveling direction.

FIG. 3 is a cross-sectional view of a structure around a gear case according to the present embodiment as viewed from a bottom surface side.

FIG. 4 is an enlarged sectional view of a structure around a counter shaft according to the embodiment.

FIG. 5 is a longitudinal sectional view of the slide gear according to the embodiment.

FIGS. 6A and 6B are views showing a brake shaft according to the embodiment, wherein FIG. 6A is a longitudinal sectional view, and FIG. 6B is a view taken in the direction of arrow B1 in FIG.

FIGS. 7A and 7B are views showing a brake drum according to the embodiment, wherein FIG. 7A is a longitudinal sectional view, and FIG.
It is an arrow view.

FIG. 8 is a view showing an assembly of the brake panel and the support pins according to the embodiment, wherein (a) is a longitudinal sectional view,
(B) is a view on arrow B3 in (a).

FIGS. 9A and 9B are views showing an assembly of the brake cam and the brake lever according to the present embodiment, wherein FIG. 9A is a longitudinal sectional view, and FIG. 9B is a view taken in the direction of arrow B4 in FIG.

FIG. 10 is a sectional view showing a structure around a conventional counter shaft.

[Explanation of symbols]

 Reference Signs List 4 rear wheel 14 drive motor 16L, 16R gear case 24 differential gear 24f final gear 26 counter shaft 30 counter gear 30a internal gear dog (clutch means) 32 slide gear 32b cylinder portion 42 brake shaft 42c engagement hole 44 coil spring 48 ball Bearing 50 Oil seal 52 Brake drum (braking means)

Claims (3)

[Claims] 1. An electric vehicle comprising: a pair of left and right rear wheels interlocked via a differential device; and a drive motor for driving the left and right rear wheels. A clutch means for connecting / disconnecting the power transmission path is provided in the power transmission path, and the brake means capable of braking the left and right rear wheels regardless of the on / off state of the clutch means is driven more than the differential device on the path. A brake structure for an electric vehicle, wherein the brake structure is arranged on a motor side. 2. A counter shaft supported by left and right gear cases, and a counter gear driven by the drive motor is provided on the counter shaft, and the power transmission path is defined by the counter gear and an axial direction on the counter shaft. And a final gear provided in the differential so as to always engage with the slide gear and to intermittently transmit power by engaging / disengaging with the counter gear. A cylindrical portion is provided at an end of the slide gear opposite to the counter gear, and is always engaged with an outer peripheral portion of the cylindrical portion in a rotational direction and capable of absorbing an axial movement of the cylindrical portion. A brake shaft having a hole is rotatably provided on the counter shaft, and a coil spring for urging the slide gear in a direction engaging with the counter gear is provided on the cylinder and the counter. 2. The electric vehicle according to claim 1, wherein the brake shaft is fitted into the counter shaft inside the engagement hole, and a brake drum is attached to an end of the brake shaft on a side opposite to the engagement hole. 3. Brake structure. 3. A ball bearing and an oil seal provided on a gear case on the brake shaft side are fitted at a position on an outer peripheral portion of the brake shaft and overlapping with the engagement hole in an axial direction. The brake structure for an electric vehicle according to claim 2.