Brake device for motorcycle

A brake device for a vehicle includes a brake pedal rotatably supported on a support shaft and extending in a front ward direction from the support shaft in the longitudinal direction of the vehicle. A master cylinder is located on the rear side of the support shaft in the longitudinal direction of the vehicle for generating a braking hydraulic pressure according to the rotational operation of the brake pedal. An operational amount detector is mechanically connected to the brake pedal for detecting the rotational amount of the brake pedal. The master cylinder includes an axis that is arranged vertically and is located above the support shaft with the operational amount detector being located on the rear side of the support shaft in the longitudinal direction of the motorcycle. Thus, the master cylinder and the operational amount detector can be densely arranged in the longitudinal direction of the vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2010-274025 filed on Dec. 8, 2010 the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a brake device for a motorcycle including a brake pedal, a master cylinder, and an operational amount detector for detecting the rotational amount of the brake pedal.

2. Description of Background Art

A technique is known wherein a potentiometer is used to obtain the operational amount of a brake pedal to provide control information for an ABS (Antilock Brake System). See, for example, FIGS. 1 and 2 of Japanese Patent Laid-Open No. Hei 9-164925.

As shown in FIG. 1 of Japanese Patent Laid-Open No. Hei 9-164925, a potentiometer (60) (the numbers in parentheses are the same as the numbers shown in Japanese Patent Laid-Open No. Hei 9-164925) and a brake pedal (40) are mounted on a bracket (30). An arm (70) extends from the brake pedal (40) to the potentiometer (60). The arm (70) is rotatable with the brake pedal (40).

As shown in FIG. 2 of Japanese Patent Laid-Open No. Hei 9-164925, a pin (71) is mounted at the front end of the arm (70). The pin (71) is engaged with a bifurcated arm (63a) extending from the potentiometer (60), so that the operational amount of the brake pedal (40) can be detected by the potentiometer (60).

In the case of applying the arrangement of the potentiometer (60) shown in Japanese Patent Laid-Open No. Hei 9-164925 to a motorcycle, the operational direction (rotational direction) of the brake pedal is changed from a longitudinal direction to a vertical direction, so that the layout of parts in the periphery of the brake pedal is susceptible to limitation.

Further, if the potentiometer (60), the brake pedal (40), and an input rod (21) are provided in a motorcycle without any changes, the potentiometer (60) and the input rod (21) are located directly below the brake pedal (40), so that it is difficult to ensure a road clearance.

SUMMARY AND OBJECTS OF THE INVENTION

It is accordingly an object of an embodiment of the present invention to provide a brake device for a motorcycle having a potentiometer that can suppress the limitation of layout of other members and can easily ensure a necessary road clearance.

It is accordingly an object of an embodiment of the present invention to provide a brake device for a motorcycle having a potentiometer that can suppress the limitation of layout of other members and can easily ensure a necessary road clearance. In accordance with an embodiment of the invention, there is provided a brake device for a motorcycle including a support shaft, a brake pedal rotatably supported to the support shaft and extending to the front from the support shaft in the longitudinal direction of the motorcycle, a master cylinder located on the rear side of the support shaft in the longitudinal direction of the motorcycle for generating a braking hydraulic pressure according to the rotational operation of the brake pedal, and an operational amount detector mechanically connected to the brake pedal for detecting the rotational amount of the brake pedal; wherein the master cylinder is located above the support shaft in such a manner that the axis of the master cylinder extends vertically, and the operational amount detector is located on the rear side of the support shaft in the longitudinal direction of the motorcycle.

In accordance with an embodiment of the present invention, the brake device further includes a support plate mounted on a vehicle body of the motorcycle, wherein a foot step is provided on the support plate so as to extend from the support plate in the laterally outward direction of the motorcycle, and the operational amount detector is provided on the lateral inside of the support plate.

In accordance with an embodiment of the present invention, the operational amount detector includes a potentiometer, and the support plate has a lower extending portion projecting downward from the lowermost end of the potentiometer.

In accordance with an embodiment of the present invention, the support shaft is supported to the support plate with a boss portion of the brake pedal being rotatably mounted on the support shaft. A first gear extends from the boss portion along the laterally inside surface of the support plate with a second gear meshing with the first gear being connected to an input shaft of the potentiometer. An inner cover is provided for covering the first gear and the second gear and is mounted on the laterally inside surface of the support plate.

In accordance with an embodiment of the present invention, the support plate has an upper extending portion, and the master cylinder is mounted on the upper extending portion of the support plate.

According to an embodiment of the present invention, the master cylinder is located above the support shaft in such a manner that the axis of the master cylinder extends vertically. If the master cylinder extends in the longitudinal direction of the vehicle or obliquely, a space cannot be ensured on the rear side of the master cylinder, causing an influence on the location of equipment.

In this respect, the present invention has an advantage such that the master cylinder is vertically positioned and a space can therefore be ensured on the rear side of the master cylinder. The operational amount detector is located in this space. Thus, the master cylinder and the operational amount detector can be densely arranged in the longitudinal direction of the vehicle. Accordingly, it is possible to provide a brake device for a motorcycle having a potentiometer which can suppress the limitation of layout of other members and can easily ensure a necessary road clearance.

Further, the space for vertically positioning the master cylinder can be ensured in the vicinity of the brake pedal where a plurality of pieces of equipment are arranged, by slightly displacing these pieces of equipment in the longitudinal direction of the vehicle. More specifically, the master cylinder can be located without any influence on the equipment provided near the brake pedal.

According to an embodiment of the present invention, the operational amount detector is provided on the lateral inside of the support plate for also supporting the foot step. Accordingly, the support plate functions as a protective cover for protecting the operational amount detector.

According to an embodiment of the present invention, the operational amount detector includes a potentiometer, and the support plate has a lower extending portion projecting downward from the lowermost end of the potentiometer. Accordingly, bouncing stones from the ground come into collision with the lower extending portion. More specifically, the potentiometer is also protected by the lower extending portion.

According to an embodiment of the present invention, the first gear and the second gear for transmitting the operational amount of the brake pedal to the operational amount detector are stored in a sealed case formed by the support plate and the inner cover.

Thus, the first gear and the second gear are stored in the sealed case, thereby ensuring a waterproof performance in the brake device.

Further, the support plate doubles as most of the sealed case, so that a compact and lightweight brake device for a motorcycle can be provided.

According to an embodiment of the present invention, the master cylinder is mounted on the upper extending portion of the support plate. Accordingly, all of the master cylinder, the foot step, the brake pedal, and the operational amount detector can be preliminarily mounted on the support plate to form an assembly, and this assembly can be mounted on a vehicle body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A mode for carrying out the present invention will now be described with reference to the attached drawings. The orientation of each drawing is the same as that of the reference numerals included therein.

As shown inFIG. 1, a motorcycle10includes a front wheel11, a rear wheel15, a steering handle16, and a vehicle body18. A front wheel speed sensor12F (F means the front side of the vehicle, and the same applies to the following), a brake disc13F and a brake caliper14F are provided in the vicinity of the front wheel11. A rear wheel speed sensor12R (R means the rear side of the vehicle, and the same applies to the following), a brake disc13R and a brake caliper14R are provided in the vicinity of the rear wheel15. A brake lever17to be operated by an operator's hand is provided on the steering handle16. A brake pedal19to be operated by an operator's foot is provided at a lower central portion of the vehicle body18. Hydraulic modulators30F and30R for adjusting a hydraulic pressure to be sent to the brake calipers14F and14R are provided on the vehicle body18. A controller21and a battery22are provided on the vehicle body18.

The mutual relation and operation of these components will now be described with reference toFIG. 2.

For ease of illustration, a front wheel braking system in a noncombination mode will now be described.

Front wheel braking is performed so as to select any one of a first mode where the rotational speed of the front wheel is zero or not greater than a predetermined value, a second mode where the rotational speed of the front wheel is greater than the predetermined value and the operational amount of the brake lever is not greater than a predetermined value, and a third mode where the rotational speed of the front wheel is greater than the predetermined value and the operational amount of the brake lever is greater than the predetermined value.

The first to third modes mentioned above will now be described in sequence with reference toFIG. 2.

First Mode:

Speed information obtained by the front wheel speed sensor12F is sent to the controller21. When the front wheel speed is determined to be less than or equal to the predetermined value, the controller21keeps closing a first solenoid valve31F (normally closed), opening a second solenoid valve32F (normally open), and closing a third solenoid valve33F (normally closed). When the brake lever17is operated, a hydraulic pressure is generated in a master cylinder34F and it is transmitted to the brake caliper14F. Accordingly, in a rest condition of the vehicle or during operation at very low speeds, each solenoid is not energized and an energy saving can therefore be expected. The brake caliper14F operates to brake the brake disc13F. The first mode is also applied in the case wherein a main switch is OFF.

When the normally closed solenoid becomes abnormal, it is maintained in a normally closed condition by the push force of a spring, whereas when the normally open solenoid becomes abnormal, it is maintained in a normally open condition by the push force of a spring.

Speed information obtained by the front wheel speed sensor12F is sent to the controller21. When the front wheel speed is determined to be greater than the predetermined value, the controller21opens the first solenoid valve31F. The second solenoid valve32F is maintained open and the third solenoid valve33F is maintained closed. The second mode is a standby mode prior to so-called BBW (the third mode).

Speed information obtained by the front wheel speed sensor12F is sent to the controller21. Further, operational amount information obtained by an operational amount detector36F is sent to the controller21. When the front wheel speed is determined to be greater than the predetermined value and the operational amount is determined to be greater than the predetermined value, the controller21keeps opening the first solenoid valve31F, closes the second solenoid valve32F, and opens the third solenoid valve33F.

Since the second solenoid valve32F is closed, the hydraulic pressure generated in the master cylinder34F is not transmitted to the brake caliper14F. Instead of the operation of the master cylinder34F, the controller21operates the hydraulic modulator30F. More specifically, the controller21starts a motor37F to rotate a camshaft39F through a reduction gear mechanism38F, thereby advancing pistons41F of master cylinders40F. A hydraulic pressure generated in the master cylinders40F is transmitted through the third solenoid valve33F to the brake caliper14F. The brake caliper14F operates to brake the brake disc13F.

The hydraulic pressure generated in the master cylinder34F is applied to a stroke simulator35F because the first solenoid valve31F is open. The stroke simulator35F operates in such a manner that a piston42F is moved against a spring43F according to the hydraulic pressure applied, so that the volume in an oil passage is increased. As a result, “play” is given to the brake lever17. That is, an operation feel of the brake lever17is maintained.

The operational amount of the brake lever17is converted into an electrical signal, which is in turn sent through a wire to the controller21. Then, the controller21controls the hydraulic modulator30F through a wire. Thus, the hydraulic modulator30F is controlled through the wires, so that this control system is referred to as a by-wire type brake system (brake-by-wire; BBW).

The first to third modes mentioned above are similarly applied to the rear wheel15and the brake pedal19. A master cylinder53and an operational amount detector54are provided in relation to the brake pedal19. The related components are affixed by the symbol R instead of the symbol F. The configuration and operation of these related components are the same as those of the components for the front wheel11, so the description thereof will be omitted herein.

In the braking system, combination braking and ABS operation are also performed.

The combination braking is performed in such a manner that when the brake lever17is operated, the front wheel11and the rear wheel15are both braked at a given braking ratio irrespective of the operation of the brake pedal19. This control is performed by the controller21.

Further, the difference between a vehicle speed and a rotational speed of the rear wheel is detected. When this difference is increased and the occurrence of slip of the rear wheel is therefore expected, a braking force applied to the rear wheel is reduced to prevent the occurrence of slip of the rear wheel. This control is similarly applied to the front wheel.

This control operation is referred to as ABS operation. More specifically, the controller21operates to return a camshaft39R and to thereby retract pistons41R, thus performing the ABS operation.

The present invention relates to a brake device50including the brake pedal19as an operating member. The detailed structure of this brake device50will now be described with reference toFIGS. 3 to 5.

FIG. 3is a perspective view of the brake device50as viewed from the lateral inside thereof in the lateral direction of the vehicle. As shown by the directional signs at the lower position inFIG. 3, the left downward direction inFIG. 3denotes the front side of the brake device50in the longitudinal direction of the vehicle, the rightward direction inFIG. 3denotes the lateral inside of the brake device50in the lateral direction of the vehicle, and the leftward direction inFIG. 3denotes the lateral outside of the brake device50in the lateral direction of the vehicle.

As shown inFIG. 3, the brake device50includes a support plate51mounted to the vehicle body18(seeFIG. 1) by a plurality of bolts49, a seesaw type brake pedal19is vertically swingably supported through a support shaft52to the support plate51on the lateral inside thereof so as to extend in a forward direction from the support shaft52in the longitudinal direction of the vehicle. A master cylinder53is connected to the brake pedal19on the rear side of the support shaft52in the longitudinal direction of the vehicle for generating pressure oil with an operational amount detector54being mounted on the lateral inside of the support plate51on the rear side of the support shaft52in the longitudinal direction of the vehicle for detecting the operational amount of the brake pedal19. A stop lamp switch56is mounted on the lateral inside of the support plate51and is connected through a spring55to the brake pedal19for generating a lighting signal for a stop lamp upon operation of the brake pedal19.

When the brake pedal19is depressed by the operator, it is rotated counterclockwise as viewed inFIG. 3. As a result, the lighting signal is generated from the stop lamp switch56. At the same time, the master cylinder53is operated to compress its piston, thereby generating pressure oil.

As is apparent fromFIG. 3, the master cylinder53is located above the support shaft52in such a manner that the axis53aof the master cylinder53extends vertically. If the master cylinder53extends in the longitudinal direction of the vehicle or obliquely, a space cannot be ensured on the rear side of the master cylinder53, causing an influence on the location of various equipment.

In this respect, the present invention has an advantage such that the master cylinder53is vertically positioned and a space can therefore be ensured on the rear side of the master cylinder53. The operational amount detector54is located in this space. Thus, the master cylinder53and the operational amount detector54can be densely arranged in the longitudinal direction of the vehicle.

The operational amount detector54for detecting the operational amount of the brake pedal19may be provided by a potentiometer, a rotary encoder, or various rotary switches. Of these detectors, a potentiometer is composed of a fixed conductor, a moving conductor, leads, and a case, so it is preferable because of its simple structure and low cost. Therefore, a potentiometer is adopted as the operational amount detector54in this preferred embodiment. The operational amount detector54will be hereinafter referred to as the potentiometer54.

The support plate51extends vertically and has a lower extending portion51aprojecting downwardly from the lowermost end of the potentiometer54by a distance A. Accordingly, bouncing stones from the ground come into collision with the lower extending portion51a. More specifically, the potentiometer54is protected by the lower extending portion51a.

As shown inFIG. 4, a perspective view of the brake device50as viewed from the lateral outside thereof in the lateral direction of the vehicle, a foot step57is mounted on the lateral outside of the support plate51so as to extend outward in the lateral direction of the vehicle. The foot step57is pivotably mounted through a pin58so as to be selectively positioned in a horizontal condition (operational condition) and in a condition (non-operational condition) rotated 90° about the pin58from the horizontal condition.

The potentiometer54is provided on the lateral inside of the support plate51which is also supporting the foot step57. Accordingly, the support plate51functions as a protective cover for protecting the potentiometer54.

The support plate51also has a triangular upper extending portion51b. The master cylinder53is mounted through two bolts59,59to the upper extending portion51bof the support plate51. Preferably, a cylinder cover61formed by bending a porous plate is sandwiched between the upper extending portion51band the master cylinder53and fastened by the bolts59,59.

Thus, the cylinder cover61is fastened to the support plate51by the common bolts59for fastening the master cylinder53, thereby reducing the number of fastening bolts.

Further, the master cylinder53can be protected by the cylinder cover61. More specifically, it is unnecessary to completely cover the lateral outside of the master cylinder53by using the upper extending portion51b. Accordingly, the upper extending portion51bcan be reduced in size.

The sectional structure of the support plate51shown inFIG. 4will now be described with reference toFIG. 5.

As shown inFIG. 5, the support shaft52is supported to the support plate51, and a boss portion19aof the brake pedal19is supported to the support shaft52. A first gear62is engaged with the boss portion19a. The first gear62extends along the lateral inside surface of the support plate51. The first gear62is preferably provided by a sector gear.

The support plate51has a plate body portion51cextending from the support shaft52to the lower extending portion51a, and an inner cover63is joined to the inside surface of the plate body portion51cso as to define a space for storing the first gear62.

A third gear64is mounted to the lower extending portion51aof the support plate51, and a second gear65is mounted to the third gear64. The second gear65is rotated by the first gear62.

The third gear64is supported through a bearing66to the plate body portion51cand also supported through a bearing67to the inner cover63.

The potentiometer54is mounted on the inner cover63. An input shaft54aextends laterally outwardly from the potentiometer54, and one end of the third gear64is engaged with the input shaft54a, thereby mechanically connecting the second gear65and the third gear64to the input shaft54aof the potentiometer54.

The number of teeth of the third gear64is smaller by one than that of the second gear65. The distance between the axis of rotation of the first gear62and the axis of rotation of the second gear65is equal to the distance between the axis of rotation of the first gear62and the axis of rotation of the third gear64. The second gear65and a wave washer75are fitted on a shaft portion of the third gear64and axially fixed by a C-shaped clip76.

The wave washer75is fixed in the condition that it is pressed and deformed by the C-shaped clip76, thereby pressing the second gear65on the third gear64.

When the first gear62is mounted in this condition, the second gear65and the third gear64mesh with the first gear62. Accordingly, the backlash between the gears becomes zero, so that the detection accuracy of the operational amount detector54can be improved.

The first gear62and the second gear65are stored in a sealed case formed by the plate body portion51cand the inner cover63, thereby ensuring a waterproof performance.

Further, the support plate51doubles as most of the sealed case (the plate body portion51c), so that a compact and lightweight brake device for a motorcycle can be provided.

The structure of the support shaft52is arbitrary. In this preferred embodiment, a flanged hollow shaft is adopted as the support shaft52. The flanged hollow shaft is a round rod with a flange68at one end thereof. From the other end of the flanged hollow shaft, a lightening hole69is formed by using a drill for weight reduction.

The support shaft52is inserted through the plate body portion51cfrom its lateral outside in such a manner that the flange68is engaged with a recess formed on the lateral outside surface of the plate body portion51c.

The support shaft52may be a rotating shaft or a non-rotating shaft.

In the case of a rotating shaft, the boss portion19aof the brake pedal19is fitted through a spline71to the support shaft52. A washer72and a C-shaped snap ring73are fitted to one end of the support shaft52(opposite to the flange68), so as to prevent the axial movement of the boss portion19a.

In the case of a non-rotating shaft, the spline71is replaced by a bearing metal mounted on the support shaft52, and the boss portion19ais slidable on the bearing metal.

By forming the flange68, the axial movement of the support shaft52toward the lateral inside can be limited. After mounting the support shaft52, the foot step57is mounted to the plate body portion51cthrough the pin58. The axial movement of the support shaft52toward the lateral outside is prevented by the C-shaped snap ring73. The foot step57also functions to subsidiarily prevent the axial movement of the support shaft52toward the lateral outside.

As shown inFIGS. 3 and 4, the support shaft52, the brake pedal19, the master cylinder53, the potentiometer54, the spring55, the stop lamp switch56, the foot step57, the cylinder cover61, the first gear62(seeFIG. 5), the third gear64(seeFIG. 5), and the second gear65(seeFIG. 5) are preliminarily mounted to the support plate51having the lower extending portion51aand the upper extending portion51b. The brake device50according to this preferred embodiment is an assembly of all the above, and the assembly can be mounted to the vehicle body18(seeFIG. 1).

In an assembly line for the motorcycle10, the brake device50thus assembled can be mounted to the vehicle body18. Accordingly, the number of man-hours for assembly in the assembly line can be greatly reduced.

The mutual relation of the components of the brake device50for a motorcycle will now be described with reference toFIGS. 6 and 7.FIG. 6is a front elevation of the brake device50as viewed from the lateral outside thereof in the lateral direction of the vehicle, andFIG. 7is a rear elevation of the brake device50as viewed from the lateral inside thereof in the lateral direction of the vehicle.

As shown inFIG. 6, the support plate51is fixed to the vehicle body (body frame)18by the bolts49,49. The support plate51has the lower extending portion51aextending obliquely downwardly in the rearward direction of the vehicle and the upper extending portion51b. The first gear62having a sectorial shape is accommodated in the lower extending portion51a. The master cylinder53and the cylinder cover61are fastened to the upper extending portion51bby the common bolts59,59.

As shown inFIG. 7as a rear elevation ofFIG. 6, the brake pedal19extends from the support shaft52in the frontward direction of the vehicle. The master cylinder53is located above the support shaft52in such a manner that the axis53aof the master cylinder53extends vertically. The operational amount detector54is located on the rear side of the support shaft52in the longitudinal direction of the vehicle (the brake pedal19being located on the front side of the support shaft52as viewed inFIG. 7). The lower extending portion51aof the support plate51projects downward from the lowermost end of the potentiometer54by the distance A.

As shown inFIG. 8, the foot step57extends from the support plate51to the lateral outside thereof. The operational amount detector54is provided on the lateral inside of the support plate51.

The support plate51extends vertically in such a manner that the support shaft52is located at the substantially central position in the vertical direction. The first gear62and the second gear65are accommodated in and in the vicinity of the lower extending portion51a.

The present invention is suitable for a rear brake device for a motorcycle.