DE19549082B4 - Vehicle brake system, especially for racing use - Google Patents

Abstract

Vehicle brake system comprising a master brake cylinder (10) and at least one wheel brake cylinder (14), with a foreign energy source (58) for actuating the vehicle brake system regardless of a driver's foot or hand force, wherein the vehicle brake system has an anti-lock control device (12), and the external energy source (58 ) the vehicle brake system is actuated so strongly that a risk of locking on a vehicle wheel braked with the wheel brake cylinder (14) occurs, characterized
in that a triggering element (64) is provided for activating the external energy source (58) and
in that this external energy source (58) effects an actuating force acting on the master brake cylinder (10).

Description

The The invention relates to a vehicle brake system, in particular a hydraulic Vehicle brake system, according to the preamble of the main claim, in particular for the Racing use (car, motorcycle) is provided.

A generic vehicle brake system is known for example from the DE 44 15 613 C1 , This vehicle brake system comprises, in addition to a master cylinder and at least one wheel brake cylinder, a foreign energy source for operating the vehicle brake system regardless of the foot or hand force of a driver. This external power source consists of an auxiliary cylinder whose input is connected to a pressure source and whose output is connected only to one of the two existing brake circuits of the vehicle brake system. To activate the external energy source is a pedal position sensor, from whose signals the operating speed of a brake pedal is determined. From a predetermined speed threshold full braking is triggered automatically.

Another vehicle brake system is known from the US 5,195,606 A , This known vehicle brake system provides an automatic braking of the vehicle to a stop, which can be triggered by a passenger or the driver by means of an emergency button. For this purpose, the known vehicle brake system on an air compressor, which actuates a foot pedal of the vehicle brake system by means of an air cylinder. It is intended for emergencies. The well-known vehicle brake system has the disadvantage that it responds slowly. It has the further disadvantage that the braking process can not be interrupted, so the vehicle is braked to a standstill. Therefore, an automatic braking while driving, for example, to brake before turning, with the known vehicle brake system is not possible. In addition, the vehicle brake system has the disadvantage that it applies a fixed braking force, which means that the vehicle wheels are either not braked with the maximum possible force, or that block the vehicle wheels. In the first case braking distance is given away, in the latter case the vehicle is no longer steerable.

Finally, another vehicle brake system with means for detecting predetermined events for the purpose of forcibly performing a braking operation is still out of the document DE 44 22 664 A1 previously known.

The vehicle brake system according to the invention with the features of the main claim has the advantage that they automatically one for the existing road surface maximum possible braking deceleration of a Vehicle causes, wherein the braking force on each vehicle the for this bike maximum possible Value achieved and the vehicle remains fully steerable. According to the invention, the Vehicle brake system is a known anti-lock control device on. For example, by means of a button attached to the steering wheel or the like. As a triggering element an automatic braking with maximum possible vehicle deceleration is initiated: With the trigger element becomes the actuator activated, over the existing vehicle brake system brakes the vehicle. The actuating device builds up a brake fluid pressure in the wheel brake cylinders that on would be sufficient to block the vehicle wheels or at least one maximum possible Braking force of the vehicle wheels causes. By means of the anti-lock device, the brake fluid pressure modulated in the wheel brake cylinders in a conventional manner, that none the wheels blocked, however, that each anti-lock wheel with the maximum possible for it Force is slowed down.

The Automatic braking can be done by releasing the trigger element to be ended. You can also after a single press of the trigger element continue until you press the button again Trigger element, by operation another switching element, by pressing an accelerator pedal or Turning a throttle grip is stopped. The automatic braking let yourself easy and especially very fast simply by finger pressure without performing any muscle power application. This has the advantage of a short brake response time and a shortest possible braking distance. The driver can until the latest potential Time to stay on the gas and can stop the automatic directly by operation of the trigger element initiate without the foot before Remove from the gas, apply to a brake pedal and this trespass to have to (or grab a handbrake lever in motorcycle sport and pull). The longest possible "stay on the gas", the latest possible start of braking and the deceleration requiring no attention from the driver with maximum possible braking force on each vehicle wheel from the beginning to the end of the automatic Braking brings decisive advantages in racing.

The under claims have advantageous embodiments and developments of the main claim the subject invention.

By the hydraulic actuation the vehicle brake system during the means of the trigger element initiated automatic braking according to claim 2 has the advantage that the Brake fluid pressure built up very quickly in the wheel brake cylinders becomes. The response time of the vehicle brake system from pressing the trigger element until the braking of the vehicle wheels with maximum possible force is minimized by using a hydraulic actuator. The response time of the vehicle brake system is thereby even in comparison to the partially practiced in racing "left brakes" shorter, where the driver has his left foot on the brake pedal while himself the right foot on the Accelerator is located.

Preferably is the actuator according to claim 6 decoupled from the vehicle brake system, d. H. conventional Brakes are possible without elements the actuating device moved would have to be. The The muscle force to be applied by the driver during conventional braking will not enlarged and the conventional braking behavior unaffected.

through a displacement and / or force sensor according to claim 7, for example handy on the Steering wheel, in particular attachable to a steering wheel spoke, can be perform a manual braking with low operating force, wherein the braking force of the actuating force dependent is. It can be so as usual brake, the operating force Applied by hand instead of by foot becomes. The right foot can stay on the gas pedal and does not need to apply the brake pedal to become.

With a gas position sensor according to claim 8, for example, a potentiometer on the accelerator pedal, on a throttle grip on a motorcycle or on a throttle valve, a plausibility check can be carried out. So For example, the actuator activated only if the driver takes back the gas, which for example can be seen at the angular velocity of the throttle, or the gas position falls below a definable threshold or is in neutral position. Furthermore, by means of the gas position sensor the automatic braking stop when the gas is opened.

The Invention will now be described with reference to a drawing embodiment explained in more detail. It demonstrate:

1 a hydraulic circuit diagram of a vehicle brake system according to the invention;

2 a hydraulic actuator according to the invention in axial section in a schematic representation; and

3 an alternative solenoid valve according to arrow III in 1 ,

4 a modified embodiment of the in 1 shown vehicle brake system according to the invention.

In the 1 illustrated, inventive hydraulic vehicle brake system has two independent brake circuits I, II. It comprises a two-circuit master cylinder 10 , to the over a anti-lock device 12 four wheel brake cylinders 14 are connected. Structure and function of such vehicle brake systems with anti-lock device are known per se and are briefly described below with reference to the in 1 Right illustrated brake circuit I explained. The brake circuit II shown on the left has the same structure and works in the same way.

One from the master cylinder 10 coming main brake line 16 branches into two wheel brake lines 18 , each to a wheel brake cylinder 14 leads with this brake circuit I brakable vehicle wheels. In every wheel brake line 18 is a 3/3 solenoid valve 20 arranged, in its basic position the master cylinder 10 with the wheel brake cylinder 14 combines. The 3/3-solenoid valve 20 forms inlet and outlet valve 20 of the wheel brake cylinder 14 , In its place can also be two 2/2-solenoid valves as separate inlet and outlet valves for each wheel brake cylinder 14 be present (not shown).

In a switching position locks the inlet and outlet valve 20 the wheel brake line 18 , In this switching position, the brake fluid in the wheel brake cylinder 14 included, the brake fluid pressure in the wheel brake cylinder 14 is held.

In a second switching position connects the inlet and outlet valve 20 to the wheel brake cylinder 14 leading wheel brake line 18 with a return line 22 , In this position, the brake fluid pressure in the wheel brake cylinder can be 14 Lower and thus the braking force of this wheel brake cylinder 14 reduce the braked vehicle wheel. To lower the brake fluid pressure in the wheel brake cylinder 14 is a return pump designed as a piston pump 24 in the return line 22 arranged by means of which located in the second switching position inlet and outlet valve 20 Brake fluid from the wheel brake cylinder 14 in the direction of the master cylinder 10 is eligible. Each of the two brake circuits I and II has its own return pump 24 on top of a ge common electric pump motor 26 are drivable.

At each vehicle wheel is a Raddrehsensor 28 attached, whose signal is an electronic control unit 30 is supplied, which evaluates the signals and the pump motor 26 and the intake and exhaust valves 20 controls. If a vehicle wheel locks, the pump motor becomes 26 switched on and thus the return pumps 24 put into operation. There is a brake pressure modulation by means of the inlet and outlet valve 20 of the tendency to block the vehicle wheel in a conventional manner.

As a foreign energy source 58 , So for the operation of the vehicle brake system regardless of the muscle power of a driver, the vehicle brake system according to the invention has a power cylinder 32 with an axial through bore having annular piston 34 on (cf. 2 ). An extended piston rod 36 of the master cylinder 10 intersperses foreign power cylinder 32 and ring pistons 34 , About her is by means of a brake pedal 38 the master cylinder 10 and thus the vehicle brake system operable in the usual way. The brake pedal 38 engages a master cylinder 10 far end of the piston rod 36 on the master cylinder 10 side facing away from the power cylinder 32 protrudes.

The ring piston 34 is on a piece of pipe 40 inside the power cylinder 32 slidable, that of a master cylinder 10 opposite side to about the middle of the cylinder 32 enough. The ring piston 34 is to the power cylinder 32 and the pipe section 40 sealed, it closes on its the master cylinder 10 side facing away from a fluid chamber 42 to his activity.

A helical compression spring 44 in the foreign power cylinder 32 pushes the ring piston 34 in the direction of the master cylinder 10 away to a basic position. By applying the fluid chamber 42 with brake fluid can the ring piston 34 on the master cylinder 10 to be moved. He reaches over a flange disc 46 firmly on the piston rod 36 is attached to the piston rod 36 and actuates in this way the master cylinder 10 and thus the vehicle brake system. About the flange disc 46 are the ring piston 34 and the piston rod 36 in conventional brake operation by means of the brake pedal 38 and thus the external energy source 58 decoupled from the vehicle brake system.

For pressurizing the fluid chamber 42 in the foreign power cylinder 32 serves a designed as a piston pump power pump 48 that by means of an electric motor 50 is drivable. A suction side of the power pump 48 is to a storage container 52 of the master cylinder 10 and its pressure side via a power-operated valve 54 with the fluid chamber 42 in the foreign power cylinder 32 connected. On the pressure side of the power pump 48 is a foreign-pressure accumulator 56 connected, the brake fluid with a pressure of, for example, 210 bar stores. The in the foreign-pressure accumulator 56 contained brake fluid volume is sufficient for several full operations of the ring piston 34 out. The power pump 48 , the external force accumulator 56 , the external force valve 54 as well as from foreign power cylinder 32 and ring pistons 34 existing actuator together form a foreign energy source 58 , by means of which the vehicle brake system is operable independently of the muscular force of a driver.

4 shows a second embodiment of a foreign energy source 58 the vehicle brake system according to the invention. Their power pump 48 is mechanically, for example via a gear drive of a vehicle engine 51 driven. This provides greater reliability. The suction side of the power pump 48 is connected to a low-pressure accumulator 53 connected via the external force valve 54 with the fluid chamber 42 of the power cylinder 32 is connected when the power-operated valve 54 is in its basic position. In low-pressure storage 53 There is a pressure of 4 bar, for example.

The power pump 48 opposite in parallel is a pressure relief valve 55 connected. This limits the pressure in the external pressure accumulator 54 to 210 bar, for example, by braking fluid against the direction of the external power pump when this pressure is reached 48 lets flow back. In the 4 illustrated Fremenergiequelle 58 is hydraulically completely isolated from the rest of the vehicle brake system. It is a higher reliability achieved because, for example, in a leak in their high pressure circuit no brake fluid is sucked out of the vehicle brake system. The usual braking function remains fully guaranteed. Otherwise, the in 4 illustrated Alienengiequelle 58 equals and works in the same way as the one in 1 , To avoid repetition, reference is made to the corresponding statements.

It is also a Bremsflüssigkeitsbeaufschlagung the foreign-pressure accumulator 56 by means of one of the two return pumps 24 the vehicle brake system in particular possible if they are not needed to return, so then if no anti-lock control. In this case, the suction side of a return pump 24 with the master cylinder 10 or its reservoir 52 and their pressure side of the brake circuits I, II separated and with the foreign force accumulator 56 get connected. This can be done by means not shown solenoid valves and brake fluid lines.

It is also possible, the brake fluid pressure of the external energy source 58 instead of the fluid chamber 42 of the power cylinder 32 directly to the two brake circuits I, II supply. The foreign power cylinder 32 and the ring piston 34 are unnecessary in this case. However, the two brake circuits I, II, when actuated by the external energy source 58 in this case, for example by means of solenoid valves from the master cylinder 10 be disconnected, otherwise the brake fluid from the external energy source 58 through the master cylinder 10 in its reservoir 52 would flow and no pressure build-up would take place in the vehicle brake system.

The external force valve 54 is a 3/2 solenoid valve. In its basic position, it connects the fluid chamber 42 in the foreign power cylinder 32 with the reservoir 52 of the master cylinder 10 , The ring piston 34 is from the helical compression spring 44 pressed into its basic position and held there. The vehicle brake system is via the brake pedal 38 operable in the usual way.

Instead of the throttle valve as a foreign force valve 54 as it is in 1 can also be a pressure control valve 65 Find use as it is in 3 is shown. This regulates the brake fluid pressure in one to the external force cylinder 32 leading brake fluid line 66 to one of the energization of its electromagnet 68 through the electronic control unit 30 given and thus variable value. The brake fluid is supplied as in 1 represented by one of the pressure side of the power pump 48 or the foreign-pressure accumulator 56 coming brake fluid line 70 , Excess brake fluid is through a brake fluid line 72 to the reservoir 52 of the master cylinder 10 dissipated. In its basic position, the pressure control valve closes 65 that of the pressure side of the power pump 58 and the foreign-pressure accumulator 56 coming brake fluid line 70 and connects those to the foreign power cylinder 32 leading brake fluid line 66 with the to the reservoir 52 of the master cylinder 10 leading brake fluid line 72 ,

In its switching position, the external force valve connects 54 the pressure side of the power pump 48 and the foreign-pressure accumulator 56 with the fluid chamber 42 of the power cylinder 30 , The ring piston 34 will go in the direction of the master cylinder 10 moved and the piston rod 36 over the flange disc 46 moved so that the master cylinder 10 and thus the vehicle brake system is actuated. The means of external energy source 58 on the piston rod 36 of the master cylinder 10 applied force is so great that the brake fluid pressure caused in the vehicle brake system is sufficient to block the vehicle wheels. The blocking of each vehicle wheel is by means of the anti-lock device 12 prevented. In this way, a maximum possible braking force of each vehicle wheel is ensured.

The power pump 48 is from the electronic control unit 30 set in motion when the brake fluid pressure on its pressure side, ie in the foreign-pressure accumulator 56 falls below a lower threshold. Upon reaching an upper threshold value, for example, 210 bar, the power pump 48 switched off. The brake fluid pressure in the foreign-pressure accumulator 56 is by means of a pressure sensor 60 converted into an electrical signal to the electronic control unit 30 is supplied.

The external force valve 54 is preferably as in 1 shown, designed as a throttle valve whose flow resistance changes in the switching position depending on its energization. In this way, the brake fluid pressure can be in the fluid chamber 42 of the power cylinder 32 regulate with higher control quality.

The maximum braking force of the vehicle wheels is dependent on the road surface, it decreases, for example, in the wet road and has only a fraction of the value of dry ice on a slippery surface. For this reason, the brake fluid pressure in the fluid chamber 42 of the power cylinder 32 and thus the operating force of the brake cylinder 10 Adjustable: Tilt all vehicle wheels very fast to block what the electronic control unit 30 by means of the signals of the wheel rotation sensors 28 determines the brake fluid pressure in the fluid chamber 42 of the power cylinder 32 with the power-operated valve 54 adjusted to a lower value, but still sufficient to block the vehicle wheels. The brake fluid pressure in the fluid chamber 42 is by means of a pressure sensor 62 measured, whose signal is the electronic control unit 30 is supplied. The reduced fluid pressure of the fluid chamber 42 of the foreign-force cylinder 32 causes a lowered brake fluid pressure in the vehicle brake system, whereby the control performance of the anti-lock device 12 is improved.

The automatic braking is triggered by the external energy source 58 for example, by pressing a button 64 , which is conveniently located, for example, on a steering wheel, not shown, and its signal to the electronic control unit 30 is supplied.

A second possibility of actuation of the vehicle brake system by means of the external energy source 58 offers a force or displacement sensor 74 as he is known and exemplary in the DE 37 08 094 C1 is described. This is handy, for example, mounted on the steering wheel, not shown. He puts the force applied to him, for example, by means of a thumb force into an electrical signal that the electronic control unit 30 is supplied. This regulates by means of the external energy source 58 and its off-axis valve 54 . 65 the brake fluid pressure in the fluid chamber 42 of the power cylinder 32 and thus the operating force of the master cylinder 10 depending on the force transmitter 74 on brought strength. In this way, a comfortable manual braking is possible, with the brake pedal 38 not pressed, the right driver's foot not on the brake pedal 38 must be implemented.

By means of a gas position sensor 76 a plausibility check is possible. The gas position sensor may, for example, be a potentiometer which is attached to a throttle valve of a carburetor or an injection system of an internal combustion engine, to an accelerator pedal or to a throttle grip. An electrical signal from the gas position sensor 76 becomes the electronic control unit 30 fed. This makes it possible to use the external energy source 58 to operate only if the gas is withdrawn, if it falls below a threshold or is in neutral position. It is also possible to stop the automatic braking as soon as the driver accelerates again.

In addition, it is possible by means of the electronic control unit 30 to control a fuel injection system so that the fuel flow rate is throttled or turned off while using the external power source 58 is slowed down. Likewise, an ignition system during braking with the external energy source 58 be turned off.

Claims (8)

Vehicle brake system with a master cylinder ( 10 ) and at least one wheel brake cylinder ( 14 ), with a foreign energy source ( 58 ) for actuating the vehicle brake system independently of a foot or hand force of a driver, the vehicle brake system having an anti-lock control device ( 12 ), and the external energy source ( 58 ) the vehicle brake system is so strong that a danger of locking on one with the wheel brake cylinder ( 14 ) braked vehicle wheel, characterized in that a triggering element ( 64 ) for activating the external energy source ( 58 ) and that this external energy source ( 58 ) one on the master cylinder ( 10 ) acting actuating force causes. Vehicle brake system according to claim 1, characterized in that it comprises a hydraulic external energy source ( 58 ) having. Vehicle brake system according to claim 2, characterized in that the external energy source ( 58 ) a throttle valve ( 54 ) for controlling an actuator ( 32 . 34 ) having. Vehicle brake system according to claim 2, characterized in that the external energy source ( 58 ) a pressure relief or pressure control valve ( 65 ) for controlling the actuator ( 32 . 34 ) having. Vehicle brake system according to one of the preceding claims, characterized in that the external energy source ( 58 ) a braking force sensor ( 62 ) having. Vehicle brake system according to one of the preceding claims, characterized in that the external energy source ( 58 ) a decoupling element ( 46 ), which the external energy source ( 58 ) decoupled from the vehicle brake system by foot or by hand when not in use or under conventional brake control. Vehicle brake system according to one of the preceding claims, characterized in that it has a displacement and / or force sensor ( 74 ), with which the external energy source ( 58 ) can be actuated away and / or force-dependent. Vehicle brake system according to one of the preceding claims, characterized in that it comprises a gas position sensor ( 76 ), whose signal is dependent on the operation of the vehicle brake system with the external energy source ( 58 ) is prevented.