Vehicle brake device

The vehicle brake device has the invalid depression region in a brake pedal operation by a driver. The vehicle brake device includes an input rod configured to move forward and rearward in conjunction with a depression operation of a brake pedal and a pedal bias unit configured to bias the input rod in a direction to which the brake pedal returns when the depression operation position of the brake pedal lies within the invalid depression region. The pedal bias unit includes an elastic body including one end portion attached to the input rod and the other end portion attached to the vehicle body side member to provide a spring force to the input rod in the direction to which the brake pedal returns.

TECHNICAL FIELD

This disclosure relates to a vehicle brake device in which there is an invalid depression region in a brake pedal operation by a driver.

BACKGROUND ART

As a conventional vehicle brake device, a device described in PTL 1 is known, for example. This vehicle brake device has a configuration in which a sleeve is coaxially disposed on an outer circumference of an input rod extending from a brake booster. The input rod receives a depression force associated with a depression operation on a brake pedal via the sleeve. Furthermore, a coil spring is disposed between the sleeve and a fixed portion of the brake booster, and the spring biases the sleeve with respect to the fixed portion, toward the brake pedal side.

Then, in the configuration of the vehicle brake device, forward and rearward movement of the sleeve associated with the depression operation on the brake pedal is not transmitted to the input rod and to the brake booster by the action of the spring, until the depression amount of the brake pedal reaches or exceeds a predetermined pedal depression amount. Furthermore, a predetermined pedal reaction force is generated due to compressive deformation of the spring at this time.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

The spring is disposed coaxially with the input rod such that the spring covers the outer circumference of the input rod at the front of the sleeve. Thus, the spring restricts a displacement of the input rod in the direction perpendicular to the axis direction, and a displacement of the brake pedal coupled to the input rod is disturbed, accordingly.

The present disclosure has been made in view of the above-mentioned problem, and has an object to allow a more displacement of the input rod in the direction perpendicular to the axis direction in the vehicle brake device in which there is the invalid depression region, even if there is an elastic body for generating the pedal reaction force.

Solution to Problem

In order to solve the above-mentioned problem, according to an aspect of the present disclosure, there is provided a vehicle brake device in which there is an invalid depression region in a brake pedal operation by a driver. The vehicle brake device includes a pedal bias unit configured to bias an input rod in a direction in which a brake pedal returns, when a depression operation position of the brake pedal lies at least within the invalid depression region, the input rod moving forward and rearward in conjunction with a depression operation of the brake pedal. The pedal bias unit includes an elastic body. One end portion of the elastic body is attached to the input rod, and the other end portion of the elastic body is attached to a vehicle body side member. The elastic body is configured to provide a spring force to the input rod in the direction to which the brake pedal returns.

DESCRIPTION OF EMBODIMENTS

Description will be made by an example of a case where a vehicle brake device according to the present disclosure is applied to a hybrid vehicle including a regeneration cooperation brake control device.

First, a configuration of a driving system of the hybrid vehicle will be described.

FIG. 1is a view illustrative of a whole system of a driving system of the hybrid vehicle to which the regeneration cooperation brake control device according to the present embodiment is applied.

As illustrated inFIG. 1, the driving system of the hybrid vehicle includes an engine E, the first motor generator MG1(generator), the second motor generator MG2, an output sprocket OS, and a power dividing mechanism TM.

The engine E may be a gasoline engine or a diesel engine, and a valve opening degree of a throttle valve thereof or the like is controlled on the basis of a control command from an engine controller41described later.

Each of the first motor generator MG1and the second motor generator MG2is a synchronous motor generator which has a rotor in which permanent magnets are embedded and a stator around which stator coils are wound. The first motor generator MG1and the second motor generator MG2are separately controlled by applying three-phase alternating currents produced by a power control unit43on the basis of a control command from a motor controller42described later.

Each of the motor generators MG1and MG2is capable of operating as an electric motor configured to rotationally drive with a power supplied from a battery44(hereinafter, such a operating state is referred to as a “driving state”). Furthermore, each of the motor generators MG1and MG2is capable of operating as a generator configured to develop an electromotive force at both ends of the stator coil to charge the battery44when the rotor is rotated by an external force (hereinafter, such an operating state is referred to as a “regeneration state”).

The power dividing mechanism TM is constituted of a simple planetary gear train including a sun gear S, a pinion P, a ring gear R, and a pinion carrier PC. A coupling relation among the three rotational elements (the sun gear S, the ring gear R, and the pinion carrier PC) of the simple planetary gear train, input members, and output members will be described. The sun gear S is coupled to the first motor generator MG1. The ring gear R is coupled to the second motor generator MG2and the output sprocket OS. The pinion carrier PC is coupled to the engine E via an engine damper ED. It is to be noted that the output sprocket OS is coupled to a left front wheel and a right front wheel via a differential, a drive shaft (not illustrated), a chain belt CB, or the like.

Next, a control system of the hybrid vehicle will be described.

As illustrated inFIG. 1, the control system of the hybrid vehicle according to the present embodiment includes the engine controller41, the motor controller42, a power control unit43, the battery44(rechargeable battery), a brake controller45, and an integration controller46.

The integration controller46is configured to receive input information from an accelerator opening degree sensor47, a vehicle speed sensor48, an engine speed sensor49, the first motor generator rotation speed sensor50, and the second motor generator rotation speed sensor51.

The integration controller46is configured to perform a function to manage energy consumption over the whole of the vehicle to run the vehicle with a highest efficiency. That is, the integration controller46is configured to control an engine operation point by the control command to the engine controller41in acceleration travelling. Furthermore, the integration controller46is configured to control a motor generator operation point by the control command to the motor controller42in stopping, travelling, braking, or the like. The integration controller46is configured to receive an accelerator opening degree AP, a vehicle speed VSP, an engine speed Ne, the first motor generator rotation speed N1, and the second motor generator rotation speed N2from sensors47,48,49,50, and51, respectively. Then, the integration controller46is configured to perform a predetermined computing processing on the basis of the inputted information to output the control commands based on the processing result to the engine controller41and the motor controller42. It is to be noted that a bidirectional communication line64is connected between the integration controller46and the engine controller41, a bidirectional communication line65is connected between the integration controller46and the motor controller42, and a bidirectional communication line66is connected between the integration controller46and the brake controller45, for information exchange.

The engine controller41is configured to output a command for controlling the engine operation point (Ne, Te) depending on a target engine torque command from the integration controller46, or the like, to a throttle valve actuator, not illustrated, for example. Herein, the integration controller46is configured to compute the target engine torque command or the like on the basis of the accelerator opening degree AP from the accelerator opening degree sensor47and the engine speed Ne from the engine speed sensor49.

The motor controller42is configured to compute a command for controlling the motor operation point (N1, T1) of the first motor generator MG1depending on a target motor generator torque command from the integration controller46, or the like. Separately from this, the motor controller42is configured to compute a command for controlling the motor operation point (N2, T2) of the second motor generator MG2depending on the target motor generator torque command from the integration controller46, or the like. Then, the motor controller42is configured to output these computed commands to the power control unit43. It is to be noted that the motor controller42is configured to use information of a battery SOC indicative of a state of charge of the battery44. Furthermore, the integration controller46is configured to obtain the target motor generator torque command or the like on the basis of the motor generator rotation speeds N1and N2from the motor generator rotation speed sensors50,51with resolvers.

The power control unit43includes a joint box, a boosting converter, an inverter for a drive motor and an inverter for a generator, which are not illustrated. Then, the power control unit43constitutes a high voltage power supply system capable of supplying the power to each of the motor generators MG1and MG2with less current. The stator coil of the second motor generator MG2is connected to the inverter for the drive motor. The stator coil of the first motor generator MG1is connected to the inverter for the generator. Furthermore, the joint box is connected to the battery44which is discharged in the driving state and charged in the regeneration state.

Furthermore, the power control unit43is configured to obtain an effective regeneration torque T(t) to output the effective regeneration torque T(t) to the brake controller45.

The brake controller45is configured to receive input information from a left front wheel speed sensor52, a right front wheel speed sensor53, a left rear wheel speed sensor54, a right rear wheel speed sensor55, a master cylinder pressure sensor57, and a brake stroke sensor58. Then, the brake controller45is configured to perform a regenerative brake cooperation control when braking by an engine brake or an operation of a brake pedal8a, by outputting a control command to the integration controller46and a control command to a brake hydraulic unit76.

Next, a basic configuration of a hydraulic brake device in a braking system to which the vehicle brake device according to the present embodiment is applied will be described with reference toFIG. 2.

InFIG. 2, reference symbol8ademotes a brake pedal to be operated by the driver to instruct a required braking torque. The brake pedal8ais disposed on a lower portion of a pedal arm8. The pedal arm8extends in the substantially vertical direction. An upper portion7of the pedal arm8is supported such that the pedal arm8is rotatable relatively to a vehicle body side member31. A rear end portion of an input rod35is coupled to a midway position in the vertical direction of the pedal arm8. Thus, the brake pedal8ais coupled to a servo unit70via the input rod35, and the servo unit70is coupled to the master cylinder74via a push rod71. Therefore, the depression force generated by depressing the brake pedal is input to the servo unit70via the input rod35. Then, the servo unit70is configured to boost the pedal depression force which depends on the depressing amount of the brake pedal8a, to move pistons74band74cin the master cylinder74forward and rearward via the push rod71. Reference symbol75denotes a reservoir tank for braking fluid.

The master cylinder74is connected to wheel cylinders60to63for the respective wheels via a pipe line constituting a hydraulic circuit76. A proportional type electromagnetic valve77for controlling fluid pressure is inserted on the upstream side of the pipe line.FIG. 2illustrates a state where the proportional type electromagnetic valve77for controlling fluid pressure is not energized and the fluid in the master cylinder74is supplied to the wheel cylinders60to63directly. The proportional type electromagnetic valve77for controlling fluid pressure is configured to adjust the fluid (fluid pressure) supplied from the master cylinder74to wheel cylinders60to63depending on a control current from the brake controller45. Furthermore, the pipe line includes a brake control pump78. The intake of the brake control pump78is connected to the master cylinder74and the exhaust port of the brake control pump78communicates with the wheel cylinders60to63. The brake control pump78is configured to increase the cylinder pressure of the wheel cylinders60to63on the basis of a control command from the brake controller45.

It is to be noted that a proportional type electromagnetic valve for controlling fluid pressure for boosting (hereinafter, referred to as “boosting electromagnetic valve”) or a proportional type electromagnetic valve for controlling fluid pressure for decompression (hereinafter, referred to as “decompression electromagnetic valve”) used for ABS control or the like may be provided on the pipe lines Lf and Lr connected to the master cylinder74such that the braking fluid pressure in the respective wheel cylinders60to63can be separately controlled. Furthermore, a master cylinder pressure sensor57is configured to detect an output pressure of the master cylinder74and to supply the detection signal to the brake controller45. Furthermore, a pressure sensor80is configured to detect brake fluid pressures in the respective wheel cylinders60to63and to output detection signals to the brake controller45.

The vehicle brake device according to the present embodiment further includes a depression invalidation mechanism100A, a pedal rearward movement suppression mechanism100b, and a pedal bias unit100C.

The depression invalidation mechanism100A is configured to make at least one hydraulic chamber74dof the master cylinder74communicate with the reservoir tank75, when the depression operation position of the brake pedal8alies within a preset invalid depression region. The depression invalidation mechanism100A is a mechanism configured to suppress a generation of a base hydraulic pressure by the master cylinder74within the invalid depression region. In the depression invalidation mechanism100A according to the present embodiment, the invalid depression region is set to be a region from a pedal depression start position to a position where the depression amount of the brake pedal reaches a preset initial depression amount. In the invalid depression region, the generation of the base hydraulic pressure by the master cylinder74is suppressed.

That is, the depression invalidation mechanism100A is a mechanism configured to invalidate a stroke of the input rod35or the push rod71corresponding to the operation of the brake pedal8awithin the invalid depression region to prevent the generation of the base hydraulic pressure in the master cylinder74. The depression invalidation mechanism100A may be provided in the servo unit70, may be provided between the brake pedal8aand the input rod35of the servo unit70like the above-mentioned prior art document, or may be provided in the master cylinder74. When the depression invalidation mechanism100A is provided in the servo unit70, the depression invalidation mechanism100A may include, for example, a mechanism to suppress the stroke of the push rod71corresponding to the stroke of the input rod35depending on the operation of the brake pedal8awithin the invalid depression region.

An example in which the depression invalidation mechanism100A is provided in the master cylinder74will be described with reference toFIG. 3.

Herein, the master cylinder74according to the present embodiment is a tandem type master cylinder74as illustrated inFIG. 3, and includes a housing74aformed in a bottomed cylindrical shape. The first and second pistons74band74care housed in the housing74aside by side, in a liquid-tight and slidable manner. A first spring74eis disposed in the first hydraulic chamber74dformed between the first piston74band the second piston74c. A second spring74gis disposed in a second hydraulic chamber74fformed between the second piston74cand a closed end of the housing74a. In this way, the second piston74cis biased to an opening end side (the first piston74bside) by the second spring74g, and the first piston74bis biased to the opening end side by the first spring74e. As a result, one end (an end on the opening end side) of the first piston74bcomes into contact with and is pressed to a tip of the push rod71extending from the servo unit70.

The housing74aof the master cylinder74is provided with a first port74hby which the first hydraulic chamber74dis communicated with the reservoir tank75and a second port74iby which the second hydraulic chamber74fis communicated with the reservoir tank75.

When the first piston74bis positioned at a first position (a returning position) in a state (a state illustrated inFIG. 3) in which the foot of the driver leaves from the brake pedal8a(that is, the brake pedal8ais not depressed), the first port74his provided at the second position away from a closing end for closing the first port74h, of the first piston74blocated at the first position by an invalid stroke distance “s” in a pressure-increasing direction of the first piston74b(direction toward the closing end: the left direction inFIG. 3). When the second piston74cis positioned at a certain position (a returning position) in a state (the state illustrated inFIG. 3) in which the foot of the driver leaves from the brake pedal8a, the second port74iis provided such a position that the position of a closing end for closing the second port74i, of the second piston74clocated at the certain position, coincides with the position of an opening end of the second port74i(that is, the second port74iis provided such a position that the closing end of the second piston74cpositioned at the certain position is about to start to close the opening the second port74i).

It is to be noted that when the first piston74bmoves from a initial position by the invalid stroke distance “s”, the restriction on generation of the base hydraulic braking force is released (release of the depression invalidation mechanism) and the brake enters a brake operation state in which the base hydraulic braking force starts rising corresponding to a state of the brake operation. The above-mentioned mechanism for constituting the invalid stroke distance “s” is the depression invalidation mechanism100A. It is preferable that the invalid stroke distance “s” be set such that the regenerative brake generates a maximum regenerative brake force when the brake operation state is a predetermined state. In this way, when the brake operation state becomes the predetermined state, the master cylinder74releases the restriction on generation of the base hydraulic braking force and the regenerative brake generates the maximum regenerative brake force.

Furthermore, the housing74aof the master cylinder74is provided with a third port74jby which the first hydraulic chamber74dis communicated with a oil pathway Lr constituting a system for rear wheels and a fourth port74kby which the second hydraulic chamber74fis communicated with a oil pathway Lf constituting a system for front wheels.

Next, the pedal rearward movement suppression mechanism100B will be described. The pedal rearward movement suppression mechanism100B is a mechanism for suppressing a rearward movement (a movement toward a driver's seat) of the brake pedal8aat the time of a front collision of the vehicle. In the present embodiment, an example to which the pedal rearward movement suppression mechanism100B is applied will be described. That is, the pedal rearward movement suppression mechanism100B is provided with a rotary supporting unit that rotatably supports the brake pedal Ba relative to a vehicle body side member31. When an impact stronger than a predetermined strength is input in a front-rear direction of the vehicle, the rotary supporting unit is displaced rearward in the front-rear direction of the vehicle to suppress the rearward movement of the brake pedal8a.

An example of the pedal rearward movement suppression mechanism100B will be described with reference toFIGS. 4 to 7.

A flange portion2C is formed on the front side of a pedal bracket2in the front-rear direction of the vehicle, and the flange portion2C is fastened and fixed to a dash lower panel30of the dash panel by bolts and nuts, not illustrated. The pedal bracket2is a member having a substantially U-shaped cross-sectional shape and includes a pair of sidewall portions2A disposed spaced from each other and an upper wall portion2B connecting the sidewall portions thereabove.

Furthermore, a pivot bracket3having a substantially U-shape is pivotally and rotatably supported by a shaft4provided on the pedal bracket2via a collar5. A pedal shaft6is provided at the pivot bracket3in front of the shaft4in the front-rear direction of the vehicle such that the pedal shaft6straddles sidewall portions3A of the pivot bracket3facing each other. A pedal arm8is pivotally and rotatably supported by the pedal shaft6via a collar7.

A slide plate9is fixed at a lower surface portion of the vehicle body side member31such as a dash upper panel connected to the upper end of the dash lower panel30and extending rearward in the front-rear direction of the vehicle. The slide plate9is a substantially flat plate-like member fixed to and overlapping the upper surface portion of the upper wall portion2B of the pedal bracket2. In the present embodiment, the slide plate9is formed in a dish shape having downward flanges9B at both sides of an upper wall9A. The flanges9B cover the upper wall portion2B of the pedal bracket2.

Specifically, the slide plate9is attached as follows. That is, bolt insertion holes10and11are formed the upper wall portion2B of the pedal bracket2and the upper wall9A of the slide plate9, respectively. Then, the rear end portion of the slide plate9is fastened and fixed to the lower surface of a vehicle side bracket32connected and disposed on the lower surface of the vehicle body side member31such as the dash panel with the upper wall portion2B of the pedal bracket2by a bolt12inserted through the bolt insertion holes10and11from a lower side of the vehicle, a fixing plate13provided on the lower surface side of the slide plate9(that is, a lower inner surface of the upper wall portion2B of the pedal bracket2), and a nut14.

Furthermore, in the present embodiment, the bolt insertion hole10of the upper wall portion2B is formed in a long hole shape extending frontward in the front-rear direction of the vehicle. In this way, the slide plate9is configured to be capable of relatively moving with respect to the pedal bracket2in the front-rear direction of the vehicle. Thus, there is constituted a collision absorbing means that allows a relative movement in the front-rear direction of the vehicle between the pedal bracket2and the slide plate9when an input in the rearward movement direction larger than a predetermined preset load is applied to the pedal bracket2, to absorb a collision by a sliding friction between the upper wall portion2B of the pedal bracket2and the upper wall9A of the slide plate9.

Furthermore, opening portions15are formed at edge portions on the both sides of the upper wall portion2B of the pedal bracket2, and hole portions (opening portions)16are formed on both side portions of a front end portion of the upper wall9A of the slide plate9. Protruding portions17are formed on front end portions of the sidewall portions3A of the pivot bracket3so as to protrude upward, and the protruding portions17are inserted through the opening portions15and the hole portions16. Then, a front end portion18of the hole portion16is engaged with a notch portion19formed on a front end portion of the protruding portion17.

Therefore, at a normal time when a collision does not occur, the front end portion18of the hole portion16of a front end portion of the slide plate9is engaged with the notch portion19of the front end portion of the pivot bracket3, as mentioned above. In this way, downward rotation of the pivot bracket3is restricted and a depression position of the pedal arm8is restricted to be positioned at a predetermined position. As a result, the pedal arm8rotates with the pedal shaft6as a fulcrum, and it is possible to make the servo unit70activate a master vac normally via the input rod35coupled with the pedal arm8.

Then, at the time of a front collision of the vehicle, the pedal bracket2relatively moves with respect to the slide plate9rearward in the front-rear direction of the vehicle within a length range of the bolt insertion hole10formed as a long hole. The relative movement releases the engagement between the protruding portion17of the pivot bracket3and the slide plate9and allows the rotation of the pivot bracket3. Thus the protruding portion17is pushed forward by a rear edge23of the hole portion16of the slide plate9. Accordingly, the pivot bracket3rotates rearward and downward with the shaft4as a fulcrum, and thus the pedal shaft6moves obliquely rearward and downward as illustrated inFIG. 7with the rearward movement of the shaft4. As a result, the pedal arm8rotates on a coupling point with the input rod35clockwise inFIG. 7, the depression position of the pedal arm8is pulled forward in the front-rear direction of the vehicle.

That is, the pedal shaft6of the pedal arm8moves rearward in the front-rear direction of the vehicle, and thus the depression position of the pedal arm8moves forward accordingly.

Furthermore, in the present embodiment, the protruding portion17is used as a rotation assist pressing portion20that comes into contact with the vehicle side bracket32provided on the vehicle body side member31when the pivot bracket3rotates to assist the rearward and downward rotation of the pivot bracket3.

The rotation assist pressing portion20is formed to have a rear end portion21protruding rearward, that is, toward the vehicle side bracket32positioned rearward thereof. As illustrated inFIG. 6A, the gap (L1) between the rear end portion21of the rotation assist pressing portion20and the vehicle side bracket32is set to be slightly larger than an engagement allowance (L) of the engaging portion between the pivot bracket3and the slide plate9.

Furthermore, as illustrated inFIG. 6B, a rear edge portion22of the rotation assist pressing portion20is formed in a curved shape. The curved shape is determined such that, when the slide plate9relatively moves forward with respect to the pedal bracket2to come into contact with the rear edge23of the hole portion16, a force component “f” input from the slide plate9to the rear edge portion22is applied substantially downward. Naturally, a gap (L2) between the rear edge portion22of the rotation assist pressing portion20and the opening portion15and a gap (L2) between the rear edge portion22and the hole portion16are set to be slightly larger than the engagement allowance (L) of the engaging portion between the pivot bracket3and the slide plate9such that the rear edge23of the hole portion16surely comes contact with the slide plate9, after the engagement of the engaging portion is released.

Furthermore, the slide plate9is provided with a restriction portion24. The restriction portion24is configured, when the rotating pivot bracket3receives a force in an opposite direction to the rotating direction of the pivot bracket3by interference between the pedal arm8and a peripheral component33, to come into contact with the rotation assist pressing portion20to restrict the rotation of the pivot bracket3in the opposite direction. The restriction portion24is provided rearward the hole portion16of the slide plate9, and includes an opening cover portion25(specifically, a portion of the upper wall9A of the slide plate9) configured to close the opening portion15of the pedal bracket2by the relative movement of the slide plate9when the input in the rearward direction larger than the predetermined load is applied to the pedal bracket2. In the present embodiment especially, the bolt insertion hole10formed in the long hole shape is formed to have such a length that the slide plate9can relatively move until the opening cover portion25of the slide plate9closes the opening portion15of the pedal bracket2.

According to the structure of the above-mentioned embodiment, since the rotation of the pivot bracket3is restricted by the slide plate9in a normal state, the pedal arm8rotates with the pedal shaft6as a fulcrum, and it is possible to make the servo unit70activate the master vac normally via the input rod35coupled with the pedal arm8.

On the other hand, at the time of a front collision of the vehicle, the slide plate9and the pedal bracket2relatively move in the front-rear direction of the vehicle within the range of the length of the bolt insertion hole10. In this way, the engagement between the pivot bracket3and the slide plate9is released to allow the rotation of the pivot bracket3. The pivot bracket3rotates rearward and downward with the shaft4as a fulcrum, and thus the depression position of the pedal arm8is pulled forward in the front-rear direction of the vehicle. Therefore, even if the servo unit70moves rearward, or even if a dash lower panel40is deformed toward a vehicle interior, and thus the input rod35extending from the servo unit moves rearward, it is possible to avoid the rearward displacement of the depression position of the pedal arm8which causes an odd feeling.

Furthermore, the rotation assist pressing portion20is projected upward the vehicle from the upper portion of the pivot bracket3. The rotation assist pressing portion20comes into contact with the vehicle side bracket32as the vehicle body side member31when the pivot bracket3rotates to assist the downward and rearward rotation of the pivot bracket3. Therefore, it is possible to forcibly rotate the pivot bracket3downward and rearward.

Furthermore, the rotation assist pressing portion20is provided rearward the engaging portion between the pivot bracket3and the slide plate9in the front-rear direction of the vehicle, and is projected toward the vehicle side bracket32positioned rearward the rotation assist pressing portion20. Furthermore, a gap between the rear end portion21of the rotation assist pressing portion20and the vehicle side bracket32is set to be slightly larger than the engagement allowance of the engaging portion. Therefore, immediately after the engagement between the slide plate9and the pivot bracket3is released, the rotation assist pressing portion20comes into contact with the vehicle side bracket32positioned rearward the rotation assist pressing portion20, and thus it is possible to promptly rotate the pivot bracket3downward and rearward.

Moreover, the rear edge portion22of the rotation assist pressing portion20is formed in the curved shape such that, when the slide plate9relatively moves forward with respect to the pedal bracket2to come into contact with the rear edge23of the hole portion16, a force component “f” input from the slide plate9to the rear edge portion22is applied substantially downward. Therefore, it is possible to more surely rotate the pivot bracket3downward and rearward.

Furthermore, the slide plate9is provided with the restriction portion24that is configured, when the rotating pivot bracket3receives the force in the opposite direction to the rotating direction of the pivot bracket3by the interference between the pedal arm8and the peripheral component33, to come into contact with the rotation assist pressing portion20to restrict the rotation of the pivot bracket3in the opposite direction. Therefore, even if the interference between the pedal arm8and the peripheral component at the time of a collision of the vehicle may generate a rotation force in the opposite direction to return the pivot bracket3to a previous position by any chance, the restriction portion24can suppress the rotation of the pivot bracket3in the opposite direction.

It is to be noted that an example in which the pedal bracket2is fixed to the vehicle side bracket32provided on the lower surface portion of the dash upper panel is described in the above description. The present disclosure is not limited thereto. The pedal bracket2may be fixed to a vehicle body side member such as a steering member, for example, that is positioned upward and rearward the dash lower panel30and extends in a vehicle width direction, for example.

Next, the configuration of the pedal bias unit100C will be described.

The pedal bias unit100C constitutes a mechanism configured to bias the input rod35in a direction to which a brake pedal8areturns (hereinafter, referred to as “returning direction”), when the depression operation position of the brake pedal8alies at least within the invalid depression region. As illustrated inFIG. 2, the pedal bias unit100C includes an elastic body82having one end portion attached to the input rod35and the other end portion attached to the vehicle body side member31to provide a spring force to the input rod35in the returning direction of the brake pedal8a. In the present embodiment, the other end portion of the elastic body82is positioned in the returning direction of the brake pedal8afrom the one end portion.

As illustrated inFIG. 8, a protruding portion81is formed on the input rod35. The protruding portion81protrudes in an outer diameter direction from the input rod35. In an example of the present embodiment illustrated inFIG. 8, the protruding portion81is formed to rise upward from the input rod35, but the protruding portion81may protrude downward or laterally. The first spring engaging portion is formed at the protruding portion81. The first spring engaging portion of the present embodiment is formed as a notch portion81aopening forward in the front-rear direction of the vehicle. The notch portion81aof the present embodiment is formed in a wedge shape having a vertical width that becomes narrower toward the rear in the front-rear direction of the vehicle. It is to be noted that the tip portion of the notch portion81amay be sharp or rounded.

A second spring engaging portion is formed at the vehicle body side member31positioned rearward from the protruding portion81in the front-rear direction of the vehicle. The second spring engaging portion of the present embodiment is formed as an opening portion on the vehicle body side member31.

The elastic body82includes a coil spring82aas a main body, and hook portions82band82cformed at the both ends in a longitudinal direction of the coil spring82aas attachment parts. Then, one hook portion82bis hooked on the notch portion81aas the first spring engaging portion and the other hook portion82cis hooked on the second spring engaging portion.

It is to be noted that the axis of the coil spring82ais set to be parallel or substantially parallel with the input rod35.

(Operation or the Like)

When the driver depresses the brake pedal8a, the input rod35moves toward the master cylinder74in conjunction with the depression amount and the push rod71also moves toward the master cylinder74depending on the movement of the input rod35. In this situation, when the depression operation position of the brake pedal8alies within the invalid depression region, at least one hydraulic chamber of the master cylinder74communicates with the reservoir tank75, and thus the master cylinder74is in a state not to generate the base hydraulic pressure.

Herein, the depression force in the operation of the brake pedal8ais formed by a reaction force by a pedal device and the servo unit70, and a hydraulic reaction force generated in the master cylinder74. The balance between the depression force and the stroke is important for improvement in controllability. However, when the invalid depression region is added as mentioned above, the pedal depression force is reduced in the invalid depression region, since the internal pressure of the master cylinder74becomes zero or decreases, and thus the controllability is worsened.

On the other hand, by providing the pedal bias unit100C, the spring force of the elastic body82is generated by the pedal bias unit100C depending on the stroke amount of the input rod35even within the invalid depression region, and the spring force of the elastic body82is added as the depression force in the operation of the brake pedal8a. As a result, the worsening of the controllability of the brake pedal8ais suppressed.

Herein, in an ordinary brake system, a necessary deceleration is obtained by controlling the hydraulic pressure in the master cylinder74depending on the operation of the brake pedal8a. In the present embodiment, however, since it is necessary to automatically control the hydraulic pressure depending on a regeneration torque in order to obtain a regeneration cooperation brake system, a certain invalid depression region in which the hydraulic pressure does not occur in the master cylinder74regardless of the pedal operation is added, and the deceleration is controlled depending on the regeneration torque and by the automatic hydraulic pressure control device in the invalid depression region.

It is to be noted that when an elastic body for reaction force is inserted between a sleeve and a servo unit such that the elastic body is coaxially disposed on the outer circumference of the input rod like the above-mentioned PTL 1, and when the input rod swings in a direction perpendicular to the axis direction, a displacement of the input rod in the direction perpendicular to the axis direction is restricted by the bending of the elastic body for reaction force in the direction perpendicular to the axis direction. On the other hand, in the pedal bias unit100C of the present embodiment, the elastic body82is disposed so as to couple the input rod35and the vehicle body side member31. Thus, it is possible to avoid bending of the elastic body82even if the input rod35is displaced in the direction perpendicular to the axis direction. Therefore, the pedal bias unit100C of the present embodiment reduces the restriction on the displacement of the input rod35in the direction perpendicular to the axis direction as compared with the elastic body of reaction force in the prior art document.

Furthermore, the elastic body of reaction force described in PTL 1 has to secure a space over the outer circumference of the input rod for dispose the elastic body between the servo unit and the brake pedal. Therefore, it is necessary to move the disposed position of the servo unit forward in the front-rear direction of the vehicle or to move the disposed position of the brake pedal rearward in the front-rear direction of the vehicle. The former may narrow an engine room and the latter may narrow the vehicle interior. On the other hand, the pedal bias unit100C of the present embodiment does not have to be disposed between the servo unit70and the brake pedal8aover the outer circumference of the input rod35. Therefore, it is possible to avoid such a problem.

Furthermore, the present embodiment includes the pedal rearward movement suppression mechanism100B for the time of a collision. That is, at the time of a front collision of the vehicle, the slide plate and the pedal bracket relatively moves in the front-rear direction of the vehicle, and thus the engagement between the pivot bracket and the slide plate is released. This allows the rotation of the pivot bracket and rotates the pivot bracket downward and rearward with the shaft as a fulcrum, and the depression position of the pedal arm8is pulled forward in the front-rear direction of the vehicle. Therefore, even if the servo unit70moves rearward or even if the dash lower panel is deformed toward the vehicle interior, and thus the push rod71extending from the servo unit70moves rearward, it is possible to avoid the rearward displacement of the depression position of the pedal arm8that causes an odd feeling. Furthermore, the rotation assist pressing portion is projected upward the vehicle from the upper portion of the pivot bracket, and the rotation assist pressing portion comes into contact with at least one of the vehicle body side member or the slide plate when the pivot plate rotates and assists the downward and rearward rotation of the pivot bracket. The opening portion from which the rotation assist pressing portion protrudes is formed on the upper wall portion of the pedal bracket and the slide plate. Therefore, it is possible to forcibly rotate the pivot bracket downward and rearward.

In this way, when the pedal rearward movement suppression mechanism100B operates to suppress the rearward movement of the brake pedal8aat the time of a front collision of the vehicle, the input rod35has to displace in the direction perpendicular to the axis direction. However, in the case in which the elastic body for reaction force like the prior art document is adopted, the operation of the pedal rearward movement suppression mechanism100B may be disturbed. That is, in a case the elastic body is combined with a brake device having a mechanism configured to suppress the rearward movement amount of the brake pedal8aat a time of a collision, as a reduction measure for influence of a collision accident to an occupant, the function of the pedal rearward movement suppression mechanism100B might be disturbed depending on how to dispose the elastic body for generating the pedal reaction force within the invalid depression region. Specifically, in the above-mentioned prior art document, there is a force pushing back the brake pedal8ato an initial position. Since the force acts to move the brake pedal8arearward, the rearward movement amount suppressing function may not operate at all, or a sufficient effect may not be obtained even if the function operates.

On the other hand, in the present embodiment, by devising an attaching method of the elastic body82, the elastic body82can serve as a biasing means in operating the pedal at a normal time, and can prevent disturbing the function of the pedal rearward movement suppression mechanism at the operating time thereof as illustrated inFIG. 9.

Furthermore, since the hook portion82bof the elastic body82is merely hooked on the notch portion81aconstituting the first spring engaging portion, the hook portion82beasily disengages from the notch portion81aas the first spring engaging portion when the rear end portion of the input rod35swings at the operating time of the pedal rearward movement suppression mechanism. The notch portion81a, especially, is formed in a wedge shape having an inclined upper portion and an inclined lower portion. Therefore, when the rear end portion of the input rod35displaces in the vertical direction, the slope of one of the upper portion and the lower portion becomes larger, and thus the hook portion82bmore easily disengages.

Herein, one end portion of the elastic body82may be attached to the pedal arm8instead of being attached to the input rod35(seeFIGS. 10A and 10B). However, when one end portion of the elastic body82attached to the pedal arm8, a moment assisting a forward movement of the brake pedal8ais undesirably applied on the pedal arm8, at the operating time of the pedal rearward movement suppression mechanism, as illustrated inFIGS. 10A and 10B. That is, as illustrated inFIG. 10A, when a spring is connected to the pedal so as to be pulled by the pedal stroke, the spring is pulled to generate a reaction force in a direction opposite to the rotation of the pedal by the rotation of the pedal and the swing of the pedal in a direction the pedal drops. On the other hand, as illustrated inFIG. 10B, when a spring is connected to the pedal so as to be compressed by the pedal stroke, the spring is compressed to generate the reaction force in the direction opposite to the rotation of the pedal by the rotation of the pedal and the swing of the pedal in the direction the pedal drops.

On the other hand, in the present embodiment, by attaching one end portion of the elastic body82to the input rod35, it is possible to suppress applying of a moment that assists the forward movement of the brake pedal8ato the pedal arm8.

Herein, the present embodiment does not limit the configuration of the servo unit70, and can be applied to any system having an invalid stroke in which the hydraulic pressure is not generated in the master cylinder74with a certain amount of the pedal operation. The servo unit70may be a negative pressure booster, a hydraulic booster, an electric booster, or the like, and the type thereof is not limited. Furthermore, any configuration and structure of the pedal rearward movement suppression mechanism may be applied.

Effects of the Present Embodiment

(1) The vehicle brake device includes the depression invalidation mechanism100A, the pedal rearward movement suppression mechanism100B, and the pedal bias unit100C configured to bias the input rod35in the returning direction of the brake pedal8a, when the depression operation position of the brake pedal8alies at least within the invalid depression region. The pedal bias unit100C includes the elastic body82having one end portion attached to the input rod35and the other end portion attached to the vehicle body side member31to provide the spring force to the input rod35in the returning direction of the brake pedal8a.

Acceding to the constitution, by applying the reaction force generated by the elastic body82to the pedal, it is possible to restrain the swing of the pedal from being disturbed even in the case in which the depression operation position of the brake pedal8alies within the invalid depression region.

Furthermore, by attaching one end portion of the elastic body82to the input rod35, it is possible to prevent the elastic body82from restricting the suppression of the rearward movement of the brake pedal8awhen the pedal rearward movement suppression mechanism100B operates. Thus, the pedal rearward movement suppression mechanism100B can operate efficiently.

Herein, when the elastic body82is attached to the pedal arm8(seeFIGS. 10A and 10B), there may be a problem that the elastic body82restricts the rotation of the brake pedal8aby the operation of the pedal rearward movement suppression mechanism100B. The present embodiment can avoid such a problem.

(2) One end portion of the elastic body82is attached to the input rod35such that the elastic body82is rotationally displaceable at least in the vertical direction.

In this way, it is possible to reduce the disturbing amount of the swing of the input rod35by the spring force of the elastic body82in the direction perpendicular to the axis direction, and to further restrain the swing of the pedal from being disturbed when the pedal rearward movement suppression mechanism100B operates. As a result, the pedal rearward movement suppression mechanism can operate more efficiently.

(3) The protruding portion81is formed on the input rod35. The protruding portion81protrudes in the outer diameter direction from the input rod35. The notch portion81ais formed at the protruding portion81. One end portion of the elastic body82is hooked on the notch portion81a.

According to the configuration, the engagement between one end portion of the elastic body82and the input rod35is easily released when the input rod35swings at the operating time of the pedal rearward movement suppression mechanism100B. When the elastic body82disengages from the input rod, there is no reaction force by the additional elastic body82restricting the swing of the pedal and the movable part (the input rod35). As a result, the pedal rearward movement suppression mechanism can operate more efficiently.

(4) The notch portion81ais formed in a shape having a vertical width that becomes narrower toward the rear in the front-rear direction of the vehicle. That is, the notch portion81ais formed in a wedge shape. It is preferable that the notch become deeper in the bias direction by the elastic body82.

According to the configuration, one end portion of the elastic body82engaged with the input rod35can easily disengage from the input rod35, when the input rod35swings more than a preset range.

According to the vehicle brake device, even in a case where the depression operation position of the brake pedal lies at least within the invalid depression region, the pedal reaction force can be generated on the brake pedal by the spring force of the elastic body. In this situation, it is not necessary to coaxially dispose the elastic body on the outer circumference of the input rod. Thus, even if there is the elastic body for generating the pedal reaction force, it is possible to allow a more displacement of the input rod in the direction perpendicular to the axis direction, accordingly.

This application claims priority from Japanese Patent Application No. 2013-027300 (filed on Feb. 15, 2013), which is incorporated herein by reference in its entirety.

While a limited number of embodiments have been described with illustration herein, it should be apparent that the present disclosure is not limited to them and modifications and adaptations to each of the embodiments on the basis of the above disclosure may occur to one skilled in the art.

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