JP2009166735A - Braking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a braking device capable of rapidly and reliably mitigating a shock given to a driver by a brake pedal during a collision of a vehicle by a simple structure. <P>SOLUTION: The braking device comprises a brake pedal 2 operated by a driver, a master cylinder 5 which is operated based on an operating force applied to the brake pedal 2 to give liquid pressure to a liquid pressure circuit 6, a rod 3 connected to the master cylinder 5, a lock cylinder 1 which has with a fluid storage part 11 for storing fluid therein and connected to the rod 3 to transmit the operating force applied to the brake pedal 2 to the rod 3, and a fluid distribution mechanism 8 capable of discharging the fluid from the fluid storage part 11 based on the result of the detection of a collision detection sensor 30 for detecting a collision of a vehicle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic brake device that pressurizes a master cylinder based on a pedaling force applied to a brake pedal and applies a braking force to a wheel.

  A general hydraulic brake device has a configuration in which a stepping force on a brake pedal by a driver is boosted by a booster to pressurize a master cylinder. The brake pedal is supported by a dashboard that rises from the floor panel at the lower part of the driver's seat in front of the vehicle. The booster and the master cylinder are arranged in the engine room on the opposite side of the brake pedal across the dashboard. When the vehicle collides forward, the dashboard may move backward together with the engine room, or the brake pedal may move backward due to a reaction force from the booster or the master cylinder, and may move toward the driver. At this time, there is a possibility that a large impact force is applied to the foot of the driver who operates the brake pedal.

  Therefore, conventionally, a brake device has been proposed that has a structure that alleviates the impact force applied to the driver by the brake pedal in the event of a vehicle collision. Japanese Patent Application Publication No. JP-A-2001-259542, which is cited below, discloses such a brake device technology. This brake device has a booster and a master cylinder on the engine room side of the dash panel, a pedal bracket is provided on the vehicle compartment side, and a brake pedal is rotatably supported by the pedal bracket. A fan-shaped gear is attached to the shaft of the brake pedal so as to rotate integrally with the shaft, and the gear is engaged with a rack formed on an input rod that transmits a pedaling force to the booster. When the driver depresses the brake pedal, the fan-shaped gear rotates to move the input rod toward the booster. Then, the master cylinder is actuated via the booster to generate brake hydraulic pressure. When the input rod moves backward due to a frontal collision of the vehicle or the like, the engagement between the sector gear and the rack is released, the brake pedal is not rotated by the input rod, and the brake pedal is prevented from moving backward. Thereby, the impact force from the brake pedal to the driver is alleviated.

  Japanese Patent Application Laid-Open Publication No. 2004-228561, which is cited below, includes a cartridge that transmits a reaction force from a master cylinder to a brake pedal, and has a configuration that reduces the impact force by reducing the reaction force in the cartridge. Is disclosed. The cartridge is provided with elastic means, and the reaction force is determined according to the compression rate of the elastic means. The compression rate of the elastic means is set by the compression means. The compression means changes the compression rate of the elastic means according to a damage risk detection command for the driver.

JP 2003-127847 A (7th-12th paragraphs, FIG. 1 etc.) JP 2005-503291 A (7th to 24th paragraphs, FIG. 1 etc.)

  The brake device described in Patent Document 1 is excellent in that the impact force applied to the driver from the brake pedal at the time of a collision or the like can be reduced. However, the brake pedal can rotate from the position where the brake pedal is depressed to the position where the engagement between the sector gear and the rack is released. In the case of a forward collision with a sudden brake, the driver depresses the brake pedal, and the driver's feet receive an impact from the brake pedal until the meshing between the gear and the rack is released. Become. In other words, the brake device of Patent Document 1 has a possibility that the effect of reducing the impact force may be limited depending on the situation.

  In addition, the brake device described in Patent Document 2 has a configuration that can reduce the impact force more quickly than the brake device disclosed in Patent Document 1. However, it is necessary to install a cartridge in the master cylinder, and the number of parts is large. For this reason, a brake device becomes large, manufacturing cost and product cost may increase, and weight may increase.

  In view of the above problems, the present invention has been invented for the purpose of providing a brake device that can quickly and surely relieve the impact force applied to the driver by the brake pedal in the event of a vehicle collision with a simple structure. Is.

The characteristic configuration of the brake device according to the present invention for achieving the above object is as follows:
A brake pedal operated by the driver;
A master cylinder that operates based on an operating force applied to the brake pedal and applies hydraulic pressure to the hydraulic circuit;
A rod linked to the master cylinder;
A lock cylinder having a fluid storage portion for storing fluid therein, provided between the rod and the brake pedal, and transmitting an operation force applied to the brake pedal in conjunction with the rod to the rod;
A fluid distribution mechanism capable of discharging a fluid from the fluid reservoir based on a detection result of a collision detection unit that detects a collision of the vehicle.

  The operating force applied to the brake pedal is transmitted to a rod linked to the master cylinder through a lock cylinder having a fluid reservoir. The fluid stored in the fluid storage unit is discharged by a fluid circulation mechanism that is driven based on the detection result of the collision detection means when the vehicle collides. As a result, the lock cylinder is not fixed to the brake pedal, and the function as the transmission means is released. That is, the operating force applied to the brake pedal is not transmitted to the master cylinder, and the reaction force from the master cylinder to the brake pedal is not transmitted. Moreover, even if the dashboard moves backward together with the engine room, the stress is not transmitted to the brake pedal. As a result, a reaction force from the master cylinder and a stress from the dashboard are applied to the brake pedal at the time of a vehicle collision, and an impact force can be suppressed from being applied to the driver's foot operating the brake pedal. Further, the lock cylinder may be provided between the master cylinder and the brake pedal. Therefore, for example, the lock cylinder can be disposed in the vehicle interior without modifying the central portion of the brake device including the master cylinder and the hydraulic circuit installed in the engine room. Therefore, the present invention can be widely applied to various brake devices, and safety can be improved by simply modifying the conventional brake device. Thus, according to this characteristic configuration, it is possible to provide a brake device that can quickly and surely relieve the impact force applied to the driver by the brake pedal in the event of a vehicle collision with a simple structure.

  In the brake device according to the present invention, the rod may be constituted by a shaft body, and the lock cylinder may be coupled to the rod so that the rod and the shaft coincide with each other.

  When the rods and the lock cylinder are connected with the axes aligned in this way, the operating force applied to the brake pedal can be efficiently transmitted to the master cylinder. Therefore, it is possible to cope with a collision without impairing the function of the brake device in normal times. In addition, since the lock cylinder provided in response to a collision can be made to have a very simple structure, mass productivity is good and the influence on the product price is small.

  The fluid stored in the fluid storage section of the brake device according to the present invention may be a liquid, and the brake device may include a reservoir for storing the liquid discharged through the fluid circulation mechanism.

  Since the liquid is basically an incompressible fluid, when the lock cylinder is configured to store the liquid in the fluid storage portion, the brake pedal is fixedly linked to the master cylinder. Therefore, in normal times, the operating force to the brake pedal is transmitted to the master cylinder with high responsiveness. Moreover, at the time of a collision, the fixed linkage state of the lock cylinder can be quickly released by discharging the liquid from the fluid reservoir. Furthermore, by having a reservoir for storing the discharged fluid, the discharged liquid is not scattered in a space where the lock cylinder is provided, such as an engine room or a vehicle interior. In particular, when oil such as brake fluid is used as the liquid, there is a possibility of vaporization, smoke generation, or ignition due to engine heat, or contamination of the passenger compartment. However, the occurrence of these undesirable situations can be suppressed by providing the reservoir.

  In the brake device according to the present invention, the lock cylinder may have a free piston structure.

  When the lock cylinder has a free piston structure, the distance between the brake pedal-side piston and the rod-side piston inside the lock cylinder can be appropriately changed according to the brake device. That is, the lock cylinder can be applied to various vehicle types and various brake devices in general, and the mass production effect is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing the configuration of the brake device of the present invention. As shown in FIG. 1, the brake device has a master cylinder 5 that operates based on an operating force applied to the brake pedal 2 and applies hydraulic pressure to the hydraulic circuit 6. The hydraulic circuit 6 applies hydraulic pressure to a wheel cylinder 7 provided corresponding to each wheel of the vehicle, and brakes each wheel. When braking the vehicle, the driver depresses the brake pedal 2. The pedaling force applied to the brake pedal 2, that is, the operating force is transmitted to the booster 4 through the rod 3, amplified and applied to the master cylinder 5. That is, the rod 3 is linked to the master cylinder 5. In the present embodiment, the operating force applied to the brake pedal 2 is transmitted to the rod 3 via the lock cylinder 1.

  The lock cylinder 1 has a fluid storage part 11 that stores a fluid therein. The fluid stored in the fluid storage unit 11 is preferably an incompressible fluid. A typical incompressible fluid is a liquid. When the lock cylinder 1 is configured by storing liquid in the fluid storage portion 11, the brake pedal 2 is fixedly linked to the master cylinder 5. That is, the brake pedal 2 is hydro-locked. Thereby, the operating force to the brake pedal 2 is transmitted to the master cylinder 5 with high responsiveness.

  In addition, the liquid stored in the fluid storage part 11 is desired to be a highly incompressible liquid without causing the lock cylinder 1 that is often configured as a metal part to rust. Specifically, low viscosity oil such as brake fluid is suitable.

  If the fluid reservoir 11 of the lock cylinder 1 is filled with an incompressible fluid, the pedaling force (operating force) applied to the brake pedal 2 is transmitted to the rod 3 with high efficiency, and the master cylinder via the booster 4 5 is transmitted. Then, hydraulic pressure is applied from the master cylinder 5 to the wheel cylinder 7 via the hydraulic circuit 6 to brake the vehicle. As described above, when the fluid reservoir 11 is filled with the incompressible fluid, braking can be performed with high responsiveness to the operation of the brake pedal 2. However, if a compressible fluid (such as air) is mixed in the fluid reservoir 11 within a range that does not impair the responsiveness, it is possible to cause the compressive fluid to absorb pedal vibration or the like due to the hunting phenomenon.

  As shown in FIG. 1, in this embodiment, the rod 3 is constituted by a shaft body. Further, the lock cylinder 1 is coupled to the rod 3 with the rod 3 and the shaft center aligned. Such a connection structure is an extremely simple structure, and can efficiently transmit the operating force to the brake pedal 2 to the master cylinder.

  Further, as shown in FIG. 1, it is preferable that the lock cylinder 1 has a free piston structure. When the lock cylinder 1 has a free piston structure, the distance between the piston 1a on the brake pedal 2 side inside the lock cylinder 1 and the piston 1b on the rod 3 side can be appropriately changed according to the brake device. That is, the lock cylinder 1 can be applied universally to various vehicle types and various brake devices, and the mass production effect is improved. In addition, the lock cylinder 1 can have a very simple structure. Furthermore, the position of the brake pedal 2 can be adjusted by adjusting the amount of fluid stored in the fluid storage unit 11.

  Of course, the structure of the lock cylinder 1 is not limited to the free piston, and may be a structure having the piston only on one side (the brake pedal 2 side). It is sufficient if the lock cylinder 1 is a cylinder structure that is fixedly linked to the master cylinder 5 at the time of non-collision and can release the fixed state at the time of collision as will be described later.

  The lock cylinder 1 is provided with a fluid circulation mechanism 8 that can discharge a fluid from the fluid reservoir 11. The fluid circulation mechanism 8 is configured by, for example, an electromagnetic valve provided with an actuator such as a valve 81 and a solenoid 82 that opens and closes the valve 81. The solenoid 82 is controlled by a brake control ECU (electronic control unit) 20 as control means. The brake control ECU 20 controls the solenoid 82 based on the detection result of the collision detection sensor 30 as the collision detection means. Specifically, the solenoid 82 is controlled so that the valve 81 is normally closed, and the solenoid 82 is controlled so that the valve 81 is opened when the collision detection sensor 30 detects a vehicle collision. Thereby, the fluid is discharged from the fluid reservoir 11 via the fluid circulation mechanism 8.

  It is preferable that the collision detection sensor 30 shares a sensor installed for controlling the operation of the airbag. As an example, such a sensor is a displacement sensor that is provided on a side member that is a member that supports a wheel and detects a displacement of a gap of a side member that contracts due to a collision, or a G sensor that detects an acceleration at the time of a collision. .

  As described above, the fluid is discharged from the lock cylinder 1 when the vehicle collides, so that the lock cylinder 1 is released from the fixed linkage state with respect to the master cylinder 5. That is, the linkage between the brake pedal 2 and the master cylinder 5 is cut off. As a result, the reaction force from the master cylinder 5 generated when the vehicle collides is not transmitted to the brake pedal 2, and the impact force applied to the driver's foot operating the brake pedal 2 can be suppressed.

  FIG. 2 shows the states of the pistons 1a and 1b of the lock cylinder 1 at the time of collision. Here, a state in which the dashboard 40 is retracted together with the engine room by a frontal collision is illustrated. The fluid is discharged from the fluid storage unit 11 via the fluid circulation mechanism 8 to be almost empty, and the pistons 1a and 1b are in a freely movable state without being linked to each other. The piston 1a is maintained in a state where it is pushed into the lock cylinder 1 by an operating force applied to the brake pedal 2. The piston 1 b is pushed into the lock cylinder 1 by the rod 3 that moves backward together with the dashboard 40. Both pistons 1a and 1b are configured not to contact each other even when both are pushed into the lock cylinder 1 to the maximum. Therefore, the stress accompanying the backward movement of the dashboard 40 is not transmitted to the brake pedal 2.

  The same applies to the reaction force from the master cylinder 5. The piston 1 b is pushed into the lock cylinder 1 by the reaction force from the master cylinder 5. However, both pistons 1a and 1b are configured not to contact each other even when both are pushed into the lock cylinder 1 to the maximum. Accordingly, the reaction force from the master cylinder 5 is not transmitted to the brake pedal 2.

  When the vehicle collides forward, as shown in FIG. 2, the driver often depresses the brake pedal 2 strongly, and stress from the dashboard 40 and reaction force from the master cylinder 5 against the brake pedal 2 are generated. If it is large, a large impact force may be applied to the driver's foot. However, in the lock cylinder 1, the impact force applied to the driver's foot is suppressed by disconnecting the linkage between the master cylinder 5 (rod 3) and the brake pedal 2.

  In order to reduce the speed of the vehicle at the time of a forward collision, it is preferable to make the braking force of the brake device function to the maximum. If the lock cylinder 1 is simply opened and the operating force to the brake pedal 2 is cut off, the master cylinder 5 will not be pressurized, and the hydraulic pressure of the hydraulic circuit 6 may be reduced to reduce the braking force of the brake device. There is. Thus, it is preferable that the brake control ECU 20 controls the fluid circulation mechanism 8 to the open side and controls the master cylinder 5 and the hydraulic circuit 6 to maintain or improve the hydraulic pressure for braking when the vehicle collides. . Of course, it is more suitable to use together with ABS (anti lock braking system), an automatic brake system, etc.

  For example, when using an automatic brake, it is preferable that the brake device has a structure capable of pressurizing the master cylinder 5 and the hydraulic circuit 6 regardless of the operation force applied to the brake pedal 2. As an example, a configuration capable of automatically pressurizing the hydraulic circuit 6 will be described. The brake device includes a valve that cuts off the connection between the master cylinder 5 and the hydraulic circuit 6, and an actuator that drives the valve. Based on the detection result of the collision detection sensor 30, the brake ECU 20 drives the actuator to place the hydraulic circuit 6 in a closed circuit state. Then, the brake ECU 20 applies a braking force to the wheel cylinder 7 by driving the pump to pressurize the hydraulic circuit 6.

  As another example, the brake device may include a mechanism that disconnects the connection between the booster 4 and the master cylinder 5. Similarly to the above, the brake ECU 20 brings the master cylinder 5 and the hydraulic circuit 6 into a closed circuit state based on the detection result of the collision detection sensor 30. Then, the brake ECU 20 applies a braking force to the wheel cylinder 7 by driving the pump to pressurize the master cylinder 5.

  In the above, at the upstream side of the position where the connection is cut off, that is, in the lock cylinder 1 linked to the brake pedal 2, the fluid is discharged and the linkage between the brake pedal 2 and the hydraulic circuit 6 is cut off. Therefore, while the braking force is maintained or improved, the reaction force accompanying pressurization is not transmitted from the hydraulic circuit 6 to the driver.

  The amount of liquid stored in the lock cylinder 1 according to the present invention is sufficient as long as the lock cylinder 1 is brought into a hydro-lock state and the brake pedal 2 can be fixedly connected. Accordingly, the amount of liquid is extremely small compared to the amount of liquid filled in the master cylinder 5 and the hydraulic circuit 6. The response at the time of the collision is preferably performed in a time equivalent to the operation time of the airbag (usually on the order of several milliseconds). Compared to the master cylinder 5 and the hydraulic circuit 6, the amount of liquid filled in the lock cylinder 1 is small, so that the discharge time is shortened and a quick response at the time of collision is possible. Of course, since the amount of liquid discharged is small, problems such as contamination due to discharged brake fluid are reduced.

  It is preferable that the fluid discharged from the fluid storage unit 11, particularly a liquid such as brake fluid, is stored in the reservoir 9. In order to achieve the object of the present invention, it is not always necessary to provide the reservoir 9 and receive the fluid discharged from the fluid reservoir 11. However, it is not preferable that liquid such as brake fluid is scattered in the vehicle interior or engine room without being received by the reservoir 9. In the case of a passenger compartment, it becomes a cause of dirt and a strange odor. Therefore, it is preferable that the reservoir 9 is provided. As described above, since the amount of liquid filled in the lock cylinder 1 is smaller than that of the master cylinder 5 and the hydraulic circuit 6, the reservoir 9 can also be reduced in size.

  The reservoir 9 is preferably provided with a circulation mechanism capable of filling the lock cylinder 1 again with the liquid discharged from the lock cylinder 1. With this configuration, the brake fluid can be returned to the fluid reservoir 11 by pulling up the brake pedal 2 and applying a negative pressure to the lock cylinder 1.

  Moreover, in the structure shown in FIG.1 and FIG.2, although the case where the lock cylinder 1 which has the fluid storage part 11, the fluid distribution mechanism 8, and the reservoir | reserver 9 were comprised separately was illustrated, these are one. It may be integrated. For example, a valve mechanism that controls the movement of fluid between both cylinders using one of the multiple cylinders as a lock cylinder and the other as a reservoir may be used as the fluid circulation mechanism.

  In the embodiment described above with reference to FIGS. 1 and 2, the operating force transmission path from the brake pedal 2 to the booster 4 is a straight line, and the lock cylinder 1 is provided in the linear path. It was explained using an example. However, the present invention is not limited to this structure, and can also be applied to a brake device having a structure in which operating force is transmitted from the brake pedal 2 to the booster 4 and the master cylinder 5 via the link means. That is, it is sufficient if the lock cylinder 1 that keeps the linkage between the brake pedal 2 and the master cylinder 5 in a normal state and cuts off the linkage in the event of a collision is provided on the transmission path of the operating force to the brake pedal 2. is there.

  Unlike the present invention, when the vehicle collides, not by the lock cylinder 1 provided separately from the main part constituting the brake device, but by discharging the liquid of the main part such as the master cylinder 5 and the hydraulic circuit 6. It is also conceivable to reduce the reaction force to the brake pedal 2. However, when such a method is used, it is difficult to reduce the impact force to the driver by the brake pedal 2 while maintaining or improving the braking force of the brake device itself. On the other hand, in the present invention, the lock cylinder 1 is provided as a separate member linked to the brake pedal 2, and the reaction force to the brake pedal 2 is suppressed without reducing the hydraulic pressure of the main part of the brake device at the time of collision. be able to.

  As described above, according to the present invention, it is possible to provide a brake device that can quickly and surely relieve the impact force applied to the driver by the brake pedal in the event of a vehicle collision with a simple structure. In a light-weight small vehicle, particularly a light vehicle with an engine displacement of 660 cc or less in Japan, the distance from the front end of the vehicle to the driver is short, and the brake pedal is more likely to give an impact force to the driver when the vehicle collides. Since the present invention can be provided at low cost with a simple structure, it can be widely applied to small cars such as light cars with low vehicle prices, and can protect many drivers. Become.

The block diagram which shows typically the structure of the brake device of this invention Explanatory drawing showing the state of the piston of the lock cylinder at the time of collision

Explanation of symbols

1: Lock cylinder 2: Brake pedal 3: Rod 5: Master cylinder 6: Hydraulic circuit 7: Wheel cylinder 8: Fluid flow mechanism 9: Reservoir 11: Fluid reservoir 30: Collision detection sensor

Claims (4)

A brake pedal operated by the driver;
A master cylinder that operates based on an operating force applied to the brake pedal and applies hydraulic pressure to the hydraulic circuit;
A rod linked to the master cylinder;
A lock cylinder having a fluid storage portion for storing fluid therein, provided between the rod and the brake pedal, and transmitting an operation force applied to the brake pedal in conjunction with the rod to the rod;
Based on the detection result of the collision detection means for detecting the collision of the vehicle, a fluid circulation mechanism capable of discharging the fluid from the fluid reservoir, and
A brake device comprising:   2. The brake device according to claim 1, wherein the rod is constituted by a shaft body, and the lock cylinder is coupled to the rod with an axial center coinciding with the rod.   3. The brake device according to claim 1, wherein the fluid stored in the fluid storage unit is a liquid and includes a reservoir for storing the liquid discharged through the fluid circulation mechanism.   The brake device according to any one of claims 1 to 3, wherein the lock cylinder has a free piston structure.

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