JP4380512B2 - Brake device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake device including a stroke simulator that generates an appropriate stroke and reaction force in response to a driver's brake operation.

  In general, the brake-by-wire using a hydraulic circuit normally transmits the hydraulic pressure according to the brake operation to the wheel cylinder by a pump or the like in a state where the hydraulic pressure path from the master cylinder to the wheel cylinder is interrupted. The hydraulic pressure path from the master cylinder to the wheel cylinder is opened, and the hydraulic pressure corresponding to the brake operation is transmitted from the master cylinder to the wheel cylinder.

  In such a brake system, when the hydraulic path from the master cylinder to the wheel cylinder is interrupted, the brake pedal and the master cylinder are generated in order to generate an appropriate pedal stroke and pedal reaction force for the driver's brake operation. In between, there is an intervening stroke simulator composed of springs. However, the spring constant is set higher than the return spring of the master cylinder to prevent the spring as a stroke simulator from being compressed during fail safe when the hydraulic pressure path from the master cylinder to the wheel cylinder is opened. (See Patent Document 1).

Other brake systems include a stroke simulator connected between the master cylinder and the wheel cylinder so that the hydraulic pressure of the master cylinder can be transmitted to either the wheel cylinder or the stroke simulator (see Patent Document 2). .
Japanese Patent Laid-Open No. 11-157439 JP 2000-335390 A

  In the conventional examples described in Patent Documents 1 and 2, none of them is provided with a booster (booster), and therefore it is not possible to assist the driver's brake operation. For example, when performing brake-by-wire, an arbitrary hydraulic pressure can be supplied to the wheel cylinder by a pump or the like, so that it is possible to increase the braking force that is output relative to the pedal depression force that is input. The presence of the sliding resistance of the piston seal in the cylinder and the reaction force of the return spring cannot assist the brake operation itself. In addition, in the conventional example described in Patent Document 1, since the spring constant of the stroke simulator is set to a value higher than that of the return spring of the master cylinder, the brake operation is increasingly heavier when performing brake-by-wire. turn into. Since the system is based on the assumption that the brake-by-wire is originally performed, it is not preferable that the driver's brake operation becomes heavier than when the brake-by-wire is stopped by fail-safe.

  Therefore, the present invention has been made paying attention to the above-mentioned problem. When a stroke simulator that generates an appropriate stroke and reaction force for a driver's brake operation is provided, the driver's brake is applied by the action of self-help. An object of the present invention is to provide a vehicle brake device that can reduce the operating force.

In order to solve the above-described problems, a vehicle brake device according to the present invention transmits a master cylinder that generates a fluid pressure when the first piston rod is pressed, and a fluid pressure generated in the master cylinder. A compression spring that sometimes elastically contracts and moves the second piston rod in accordance with the elastic contraction, and an input unit that inputs a driver's brake operation are provided at one end, and between the one end and the other end Is connected to the first piston rod in a state where the intermediate portion is rotatable via the first clevis, and is connected to the second piston rod in a state where the other end portion is rotatable via the second clevis. When the driver's brake operation is input to one end, the moving force of the second piston rod accompanying the elastic contraction of the compression spring has the intermediate portion as a fulcrum in the same direction as the input of the brake operation. Times Characterized in that it comprises a brake operation element is transmitted as a force for assisting the.

That is, when a driver's brake operation is input to one end of the brake operator, the brake operator first rotates around the second clevis to press the first piston rod , so that the fluid is generated by the master cylinder. Pressure is generated. When the compression spring is elastically contracted by the fluid pressure generated in the master cylinder, the second piston rod connected in a state where the other end of the brake operator can be rotated moves. Rotation with the intermediate part of the brake operator in the same direction as the operation input as a fulcrum is assisted.

  According to the vehicle brake device of the present invention, when the driver's brake operation is input to one end portion of the brake operator and the stroke simulator elastically contracts, the second piston moves the intermediate portion of the brake operator. It will move so as to assist in the rotation of the fulcrum. Since the rotation of the brake operator with the intermediate portion as a fulcrum is the same as the input direction of the brake operation, the driver's brake operation can be lightened by the amount of assisting the rotation. Therefore, the driver's brake operation force can be reduced by the self-assist action without providing a booster such as a negative pressure booster.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the present invention. The brake pedal 1 (brake operator) in which a driver's brake operation is input to the pedal pad 1a (input unit) at one end is provided between the one end and the other end via a clevis 2 (first clevis). The other end is pivotally supported by the output rod 5 via a clevis 4 (second clevis) .

The push rod 3 is connected to a tandem master cylinder 7 fastened to the dash panel 6 with bolts and nuts.
A secondary return spring 7a, a secondary piston 7b, a primary return spring 7c, and a primary piston 7d are sequentially inserted into the master cylinder 7, and the tip of the push rod 3 abuts on the primary piston 7d in a pivotable manner. A pressure chamber 7e (7f) filled with brake fluid via a return spring 7a (7c) communicates with a reservoir tank 7i via a relief port 7g and a hose 7h. Here, the push rod 3, the secondary piston 7b, and the primary piston 7d correspond to the “first piston rod ”.

  In the master cylinder 7, when the push rod 3 moves forward and the pistons 7b and 7d move forward against the elastic force of the return springs 7a and 7c, the pistons 7b and 7d immediately close the relief port 7g and the pressure chambers 7e. 7f is sealed, and hydraulic pressure is generated in the pressure chambers 7e and 7f in accordance with the subsequent advancement of the pistons 7b and 7d. Further, when the pistons 7b and 7d and the push rod 3 are retracted due to the rising hydraulic pressure and the elastic force of the return springs 7a and 7c, the hydraulic pressure generated in the pressure chambers 7e and 7f is reduced and again. When the relief port 7g is opened and communicated with the reservoir tank 7i, the hydraulic pressure generated in the pressure chambers 7e and 7f disappears.

The hydraulic pressure generated in the master cylinder 7 can be transmitted to a stroke simulator 9 that is also built in the cylinder body via a flow path 8 formed in the cylinder body of the master cylinder 7.
The stroke simulator 9 is connected to a cylinder chamber 9a communicating with the flow path 8 and an output rod 5 that passes through the dash panel 6 and is slidably inserted into the cylinder body, and is slidable within the cylinder chamber 9a. and the piston 9 b, are interposed by a compression spring 9c for biasing the piston 9b in the backward direction, in configuration between the inner surface and the piston 9b of the cylinder chamber 9a. In addition, the section behind the piston 9b in the cylinder chamber 9a is open to the atmosphere. Further, the output rod 5 is prevented from wobbling by a guide member 6 a fixed to the dash panel 6. Here, the output rod 5 and the piston 9b correspond to the “second piston rod”.

  A gate valve 10 (second on-off valve) is interposed in the flow path 8. This gate valve 10 is a two-port, two-position switching, spring-offset type electromagnetically operated valve, and is configured to close the flow path at a non-excited normal position. Since the gate valve 10 only needs to be able to open and close the flow path, the flow path may be closed at the excited offset position.

  In the stroke simulator 9, when the hydraulic pressure is transmitted from the master cylinder 7 with the gate valve 10 opened, the piston 9b is pressed and the compression spring 9c is elastically contracted. The output rod 5 advances with advance. Further, when the hydraulic pressure from the master cylinder 7 is reduced and the compression spring 9c is extended by the elastic force, the piston 9b and the output rod 5 are retracted.

On the other hand, when the gate valve 10 is closed, the hydraulic pressure transmission from the master cylinder 7 to the stroke simulator 9 is prevented, so that the output rod 5 is also prevented from moving forward and is in a stationary state.
With the above configuration, when a pedal depression force is input to the brake pad 1a, the brake pedal 1 first rotates around the clevis 4 at the other end to move the push rod 3 forward. appear. When the stroke simulator 9 is elastically contracted by this hydraulic pressure, the output rod 5 that pivotally supports the other end portion of the brake pedal 1 moves forward, so that the brake pedal is in the same direction as the input of the brake operation by the driver. The rotation with the clevis 2 of 1 as a fulcrum is assisted.

  Further, as shown in FIG. 2, the hydraulic pressure generated in the master cylinder 7 can be transmitted to the wheel cylinders 11FL to 11RR disposed on the wheels. Specifically, the hydraulic pressure on the primary side can be transmitted to the rear left and right wheel cylinders 11RL and 11RR, and the hydraulic pressure on the secondary side can be transmitted to the front left and right wheel cylinders 11FL and 11FR. Here, a front / rear split system in which the brake system is divided by front and rear wheels is adopted, but of course, a diagonal split system in which the brake system is divided by front left and rear right and front right and rear left may be adopted.

Each of the wheel cylinders 11FL to 11RR is incorporated in a disc brake that presses a disc rotor with a brake pad to generate a braking force, or a drum brake that generates a braking force by pressing a brake shoe against the inner peripheral surface of the brake drum. Yes.
In the hydraulic system on the primary side, the flow between the gate valve 12r (first on-off valve) that can close the flow path between the master cylinder 7 and the wheel cylinders 11RL and 11RR, and the flow between the gate valve 12r and the wheel cylinder 11RL (11RR). An inlet valve 13RL (13RR) capable of closing the passage, and an outlet valve 14RL (14RR) capable of opening a flow path communicating between the inlet valve 13RL (13RR) and the wheel cylinder 11RL (11RR) and the reservoir tank 7i of the master cylinder 7. And a pump 15r having a suction side communicating between the outlet valves 14RL and 14RR and the reservoir tank 7i and a discharge side communicating between the gate valve 12r and the inlet valves 13RL and 13RR.

  Here, the gate valve 12r, the inlet valves 13RL and 13RR, and the outlet valves 14RL and 14RR are two-port, two-position switching, spring-offset electromagnetic operation valves, respectively. The gate valve 12r and the inlet valves 13RL and 13RR are The flow path is opened at the non-excited normal position, and the outlet valves 14RL and 13RR are configured to close the flow path at the non-excited normal position. Each valve only needs to be able to open and close the flow path. Therefore, the gate valve 12r and the inlet valves 13RL and 13RR open the flow path at the excited offset position, and the outlet valves 14RL and 14RR are excited. The flow path may be closed at the position.

The pump 15r is configured by a positive displacement pump such as a gear pump, a vane pump, a piston pump or the like that can ensure a substantially constant discharge amount regardless of the load pressure.
With the above-described configuration, the reservoir valve 13RL (13RR) and the outlet valve 14RL (14RR) are left in a non-excited normal position, and the gate valve 12r is excited and closed, and the pump 15r is driven, whereby the reservoir tank The brake fluid of 7i is sucked and the hydraulic pressure of the wheel cylinder 11RL (11RR) can be increased by the discharge pressure.

  In addition, the gate valve 12r and the inlet valve 13RL (13RR) are energized and closed while the outlet valve 14RL (14RR) is in the non-excited normal position, so that the reservoir tank 7i and the wheel cylinder 11RL (11RR) are closed. Each flow path to the pump 15r can be blocked, and the hydraulic pressure of the wheel cylinder 11RL (11RR) can be maintained.

Further, the outlet valve 14RL (14RR) is excited and opened, and the gate valve 12r and the inlet valve 13RL (13RR) are excited to close each other, whereby the hydraulic pressure of the wheel cylinder 11RL (11RR) is reduced to the reservoir tank 7i. And can be decompressed.
Furthermore, the hydraulic pressure from the master cylinder 7 is transmitted to the wheel cylinder 11RL (11RR) by setting all of the gate valve 12r, the inlet valve 13RL (13RR), and the outlet valve 14RL (14RR) to the non-excited normal position. It becomes a normal brake.

The secondary hydraulic system also includes the same gate valve 12f (first on-off valve) as the primary side, inlet valves 13FL and 13FR, outlet valves 14FL and 14FR, and a pump 15f. Since it is the same as that of the primary side, its detailed description is omitted.
Therefore, when both the gate valves 12f and 12r are closed, hydraulic pressure transmission from the master cylinder 7 to the wheel cylinders 11FL to RR is prevented.

The gate valve 10 shown in FIG. 1 and the gate valves 12f and 12r, inlet valves 13FL to 13RR, outlet valves 14FL to 14RR, and pumps 15f and 15r shown in FIG. 2 are driven and controlled by a controller 16 composed of, for example, a microcomputer. .
The controller 16 transmits the hydraulic pressure generated in the master cylinder 7 only to the stroke simulator 9 by closing the gate valves 12f and 12r and opening the gate valve 10 at the normal time when performing brake-by-wire. As a result, the compression spring 9c of the stroke simulator 9 is pressed by the piston 9b and elastically contracts, thereby generating an appropriate pedal stroke and pedal reaction force for the driver's braking operation. At this time, since the output rod 5 also moves forward in accordance with the advancement of the push rod 3, the controller 16 detects the advance amount of the push rod 3 and the advance amount of the output rod 5 by a stroke sensor (not shown), and the driver The inlet valves 13FL to 13RR, the outlet valves 14FL to 14RR, and the pumps 15f and 15r are driven and controlled so that the braking force corresponding to the pedal depression force is generated.

  On the other hand, at the time of fail-safe such as a pump failure, the gate valves 12f and 12r are opened and the gate valve 10 is closed, so that the hydraulic pressure generated in the master cylinder 7 is transmitted only to the wheel cylinders 11FL to 11RR. At this time, since the forward movement of the output rod 5 is prevented, the hydraulic pressure corresponding to the forward movement amount of the push rod 3 is simply transmitted from the master cylinder 7 to the wheel cylinders 11FL to 11RR, and the hydraulic pressure corresponding to the driver's pedaling force is controlled. Power is generated.

Here, the control processing of the controller 16 that opens the gate valve 10 and closes the gate valves 12f and 12r, and the control processing of the controller 16 that closes the gate valve 10 and opens the gate valves 12f and 12r are switched. Corresponds to “means”.
Next, operations and effects of the first embodiment will be described.
When normal brake-by-wire is performed, when the pedal depression force is input to the brake pad 1a from the non-operating state of the brake pedal 1 in FIG. 3A, first, as shown in FIG. 1 rotates with the clevis 4 at the other end as a fulcrum to advance the push rod 3, so that hydraulic pressure is generated in the master cylinder 7. At this time, since the gate valve 10 is opened and the gate valves 12f and 12r are closed, the hydraulic pressure generated in the master cylinder 7 is transmitted only to the stroke simulator 9.

Therefore, in the stroke simulator 9, the compression spring 9 c is elastically contracted according to the transmitted hydraulic pressure, and the output rod 5 that pivotally supports the other end of the brake pedal 1 moves forward accordingly. The rotation in the same direction as the input of the pedal depression force with the clevis 2 as a fulcrum is assisted.
That is, when the pedal effort of the driver is input, the output rod 5 moves forward so as to assist the rotation with the clevis 2 at the intermediate portion of the brake pedal 1 as a fulcrum. Since the rotation of the brake pedal 1 with the clevis 2 as a fulcrum is in the same direction as the input of the pedal effort, the driver's brake operation can be lightened by the amount of assisting the rotation. Therefore, the driver's pedal effort can be reduced by the self-assist action without providing a booster such as a negative pressure booster.

On the other hand, when the brake-by-wire is stopped by fail-safe, the gate valve 10 is closed and the gate valves 12f and 12r are opened, so that the hydraulic pressure generated in the master cylinder 7 is transmitted only to the wheel cylinders 11FL to 11RR. Is done.
Accordingly, the output rod 5 is prevented from moving forward and is in a non-moving state, and the brake pedal 1 simply turns around the clevis 4 as a fulcrum.

  If the output rod 5 is moved forward to assist the rotation with the clevis 2 of the brake pedal 1 as a fulcrum, as in the case of brake-by-wire, the pedal stroke increases instead of reducing the driver's brake operation. It will be. This is a loss stroke for fail safe when the driver's pedal effort is to be converted into braking fluid pressure without waste.

Therefore, even if pedal depression force is inputted, the forward movement of the output rod 5 is prevented, and the occurrence of a loss stroke can be prevented by simply rotating the brake pedal 1 around the clevis 4 as a fulcrum.
As described above, when performing the brake-by-wire, the gate valve 12f / 12r is closed and the gate valve 10 is opened, and when the brake-by-wire is stopped by fail-safe, the gate valve 12f / 12r is opened and the gate is opened. Since the valve 10 is configured to be switched to a closed state, when performing the brake-by-wire, the driver's pedaling force can be reduced by the self-assist action, and when the brake-by-wire is stopped by one fail-safe. The occurrence of a loss stroke can be prevented.

In addition, since the system is based on the assumption that the brake-by-wire is originally performed, it is possible to avoid a situation in which the driver's brake operation becomes heavier than when the brake-by-wire is stopped by fail-safe.
In addition, in said 1st Embodiment, although the master cylinder 7 and the stroke simulator 9 are comprised integrally, it is not limited to this, You may make it each comprise separately.

  Moreover, in said 1st Embodiment, although it has arrange | positioned so that the connection direction of the stroke simulator 9 with respect to the brake pedal 1 may become the same as the connection direction of the master cylinder 7, it is not limited to this, FIG. As shown in FIG. 5, the connecting direction of the stroke simulator 9 to the brake pedal 1 may be made to be opposite to the connecting direction of the master cylinder 7. In this case, the rod that pivotally supports the other end of the brake pedal 1 may be configured to be immersed in the stroke simulator 9 when the stroke simulator 9 is elastically contracted. In short, when a pedal depression force is input to one end of the brake pedal 1, the movement force of the piston 9 b due to the elastic contraction of the stroke simulator 9 is the rotation with the clevis 2 as a fulcrum in the same direction as the input of the pedal depression force. Any structure may be used as long as it is transmitted to the brake pedal 1 as a force for assisting the movement.

In the first embodiment, the hydraulic brake using the hydraulic pressure as the transmission medium is employed. However, the present invention is not limited to this, and an air brake using the compressed air as the transmission medium may be employed. Good.
Furthermore, in said 1st Embodiment, although the brake-by-wire using a fluid pressure is performed, it is not limited to this. Since it is only necessary to be able to control the braking force for the brake-by-wire, an electric brake that clamps the disc rotor with the brake pad or presses the brake shoe against the inner peripheral surface of the brake drum by controlling the driving of the electric actuator. Any brake may be used as long as it has an electronically controllable energy source such as a regenerative motor brake.

In the first embodiment, the brake-by-wire is performed according to the brake operation amount detected by the stroke sensor. However, the present invention is not limited to this, and the brake-by-wire is determined according to the pedal depression force detected by the pressure sensor. May be performed.
Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, as shown in FIG. 4, the check valve 17 and the throttle valve 18 are interposed in parallel between the stroke simulator 9 and the gate valve 10 in the first embodiment described above. Except for this, since it has the same configuration as that of the first embodiment, the parts corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

Here, the check valve 17 is arranged in a direction that allows only the passage of brake fluid to the stroke simulator 9. In addition, the throttle valve 18 is for causing the brake fluid sent from the master cylinder 7 to the stroke simulator 9 to flow around to the check valve 17 side, and the flow rate passing through the check valve 17 and the throttle valve 18. Are set to the same level.
Therefore, when performing brake-by-wire, the brake fluid passes through the check valve 17 and the throttle valve 18 when the pedal is depressed, but the brake fluid passes only through the throttle valve 18 when the pedal is returned. Thereby, the brake hysteresis can be produced when the pedal is depressed and when the pedal is returned, and the pedal feeling can be improved.

  Other functions and effects are the same as those of the first embodiment described above.

It is a schematic block diagram of 1st Embodiment. It is a figure of the hydraulic circuit which performs a brake-by-wire. It is a conceptual diagram which shows the effect of this invention. It is a schematic block diagram of 2nd Embodiment. It is the Example which made the connection direction of the stroke simulator with respect to a brake pedal and the connection direction of a master cylinder make it correspond.

Explanation of symbols

1 Brake pedal (brake operator)
2 Clevis 3 Input rod 4 Clevis 5 Output rod 6 Dash panel 7 Master cylinder 7a, 7c Return spring 7b, 7d Piston 7e, 7f Pressure chamber 7g Relief port 7h Hose 7i Reservoir tank 8 Channel 9 Stroke simulator 9a Cylinder chamber 9b Piston 9c Compression spring 10 Gate valve (second on-off valve)
11FL to 11RR Wheel cylinder 12f / 12r Gate valve (first on-off valve)
13FL-13RR Inlet valve 14FL-14RR Outlet valve 15f / 15r Pump 16 Controller 17 Check valve 18 Throttle valve

Claims (2)

A master cylinder that generates fluid pressure when the first piston rod is pressed;
A compression spring that elastically contracts when the fluid pressure generated in the master cylinder is transmitted, and moves the second piston rod in accordance with the elastic contraction;
An input portion for inputting a driver's brake operation is provided at one end portion, and an intermediate portion between the one end portion and the other end portion is pivotable via the first clevis to the first piston rod . A brake operator connected to the second piston rod in a state where the other end is rotatable via a second clevis ;
A wheel cylinder that generates a braking force by a fluid pressure transmitted from the master cylinder, a first on-off valve that can open and close a flow path between the master cylinder and the wheel cylinder, and a fluid pressure from the master cylinder. A flow path for transmitting to the compression spring, a second on-off valve capable of opening and closing the flow path, and a switching means for switching between opening and closing of the first on-off valve and opening and closing of the second on-off valve,
The switching means is
When the fluid pressure generated in the master cylinder is transmitted to the wheel cylinder, the second piston rod is moved by opening the first on-off valve and closing the second on-off valve. Stop,
When the fluid pressure generated in the master cylinder is transmitted to the compression spring, the first on-off valve is closed and the second on-off valve is opened to operate one end of the brake operator. when's braking operation is input, the moving force of the second piston rod due to the elastic contraction of the compression spring, and in and fulcrum said first clevis at the input the same direction of the brake operation the vehicle brake device comprising a Turkey to assist the rotation of the brake operation element. A check valve and a throttle valve interposed in parallel between the second on-off valve and the compression spring , wherein the check valve is disposed in a direction allowing only passage of fluid to the compression spring; The vehicular brake device according to claim 1 , wherein

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