DE102007031750A1 - Vehicle brake system operating method, particularly motor cycle integrated brake system, involves designing or activating part of valves in such manner that pump piston of brake circuit is brought in position at upper dead center - Google Patents

Abstract

The method involves designing or activating a part of the valves in such a manner that the pump piston of a brake circuit (1) is brought in a position at the upper dead center during or after a completion of an actuation of the brake actuating element (5). The brake actuating element is hydraulically connected with a brake circuit.

Description

The The invention relates to a method according to the preamble of claim 1 and a vehicle brake system according to the preamble of claim 9th

The Motorcycle has been a cost-effective over the past few decades Means of transportation developed into a recreational vehicle in which Increases both the safety and the comfort of the driver is brought to the fore.

Similar to automobiles a few years ago, motorcycles are increasingly equipped with anti-lock braking systems (ABS). From the EP 0 548 985 B1 For example, an anti-lock device for motorcycles is known.

Traditionally have motorcycles one actuator each for each the two brake circuits. Mostly the front wheel brake is replaced by a "hand brake lever" and the rear wheel brake operated by a "foot brake lever".

In the context of motorcycles, an "integral brake system" is understood as meaning a brake system in which the brake of the second brake circuit is additionally braked when the handbrake lever or the footbrake lever is actuated However, combinations are also possible in which one brake lever acts on one wheel and the other brake lever acts on both wheels (partial integral brake) DE 38 03 563 A1 and DE 103 16 351 A1 known.

at motorcycles with integral function occurs due to the actuation of a single actuator (e.g., hand brake lever and / or foot brake lever) the automatic Brake force distribution or the brake pressure distribution between the front wheel and Rear wheel either by a fixed hydraulic connection, by means of which the braking force distribution in a predetermined ratio unchangeable is given, or over an electronics, by means of which the predetermined brake force distribution is controlled.

From the JP 2000071963 A is known a braking system for motorcycles, which ensures the functionality of ABS and integral brake. The brake system has a hydraulically actuated front and rear brake, in which can be constructed together and independently of each other via a foot and hand operated master cylinder brake pressure in the wheel brakes. For brake slip control (eg anti-lock function or electronic brake force distribution), electromagnetically activatable intake and exhaust valves and a dual-circuit pump drivable by an electric motor are used in the front and rear wheel brake circuits. Furthermore, in addition to the inlet and outlet valves and the pump additionally electrically operated isolation and changeover valves in the two brake circuits available to build electro-hydraulically manual pressure on one of the two master cylinder brake pressure in the non-manually operated brake circuit (integral function), including the Pump and the separating and switching valve are electrically activated in not manually operated brake circuit.

Currently find in the field of motor vehicle brake systems mostly eccentric driven piston pumps, e.g. Radial piston pumps, use, wherein each brake circuit of the vehicle brake system assigned an independent piston-cylinder unit which operates in opposite directions with respect to the other piston-cylinder unit. In other words, there is a piston-cylinder unit in an intake stroke while the other piston-cylinder unit in a displacement stroke located.

at Semi-integral and fully integral braking systems will give the driver the advantage These systems are very common use, i. through the operation either the foot brake or the hand brake lever is not the driver (manually) actuated Brake actively pressurized. But that means that the operated by the driver (manually) Brake should experience no active pressure buildup, which is usually is achieved in that the pressure medium inflow through a closed Changeover valve is prevented. One already in the corresponding Piston-cylinder unit located (brake fluid) volume when the Pump piston e.g. is at its bottom dead center, but becomes on Start of full integral / partial integral braking when the pump for one active pressure build-up in the other (not manually operated) Brake circuit starts, inevitably ejected. This leads to to a reaction on the brake lever / brake pedal, which the driver perceived as disturbing can.

Of the Invention is therefore the object of the above-described Problem of disturbing retroactive effect on a brake lever, which by pushing out one already in the pump located brake fluid volume (dead volume) can arise to minimize or at least partially remedy. So should one Comfort improvement when braking can be achieved. In addition, to the implementation costs as possible to keep low, no additional Hardware be used.

These The object is achieved by the Method according to claim 1 solved.

In Generalization according to the invention under a "manual" operation not only the operation understood with one hand but also the operation with one foot.

Of the Invention is based on the idea in a vehicle brake system with two brake circuits and a dual-circuit engine-piston pump unit by suitable structural design and / or control at least a portion of the valves the pump piston of a brake circuit during or after completion of an operation a brake actuator to bring into a position at top dead center. This will be the In the pump piston remaining brake fluid volume (dead volume) minimized, and so it comes with the next start of the pump, if that Remaining residual volume on the pressure side in the wheel brake promoted is in the associated Brake circuit too little or no feedback on the corresponding Brake actuator.

Prefers is the control of the valves to the pump piston of a brake circuit to bring into a position at top dead center, during the Termination of an operation a brake actuator carried out, because then there is enough pressure level difference between the brake circuits available is to the position of the pump piston to top dead center cause.

The Termination of the operation the brake actuating element is preferred on the basis of a solution the brake actuating element recognized, particularly preferably on the basis of the admission pressure (master cylinder pressure), for which very particularly preferably a pressure sensor is used.

Prefers the method is performed in a brake system in which the actuated brake actuator is hydraulically connected to only one brake circuit, wherein the pump piston of that Brake circuit, which with the brake actuator hydraulically is brought into position at the top dead center. This will, as described above, at the next start of the pump a retroactive effect on the pressed Brake actuator prevented or minimized.

As well it is preferred to carry out the process in a brake system, which a hand brake lever and a foot brake lever, wherein the handbrake lever hydraulically with only one of the two brake circuits is connected and the foot brake lever only hydraulically connected to the other brake circuit, and wherein the pump piston of that brake circuit in a position at the top Dead center is brought, which connected to the handbrake lever is. This has the advantage that repercussions on the handbrake lever prevented or minimized, since repercussions on the handbrake lever by the driver usually as disturbing be perceived as reactions on the foot brake lever. Particularly preferred is the pump piston of the brake circuit, which connected to the hand brake lever, during or after completion the operation of the handbrake lever brought into the position at top dead center. But it is additional also particularly preferred that the pump piston of the brake circuit, which is connected to the hand brake lever, during or after completion the operation the foot brake lever is brought into the position at top dead center. This is how it is the pump piston of the brake circuit, which with the handbrake lever is connected in the position at top dead center after each actuation of a Brake lever, independent, whether the hand or the foot brake lever actuated was, so the repercussions be prevented or minimized on the hand brake lever in any case.

According to one another preferred embodiment the method according to the invention is in a brake system, which is a hand brake lever and a Brake pedal includes, wherein the handbrake lever only with one of the two brake circuits hydraulically connected and the foot brake lever only with the other Brake circuit is hydraulically connected, learned which brake lever the driver more often actuated, and then the pump piston of that brake circuit in the position brought at the top dead center, which is connected to the more frequently actuated brake lever is. This ensures that the reaction to the brake lever, which more often actuated is, is suppressed or reduced, whereby an improved Comfort for the driver is reached. Again, it is particularly preferable that the pump piston of the more common manually operated Brake circuit during or after completion of the operation both the hand brake lever and the foot brake lever in the position is brought to top dead center, so as to achieve the greatest possible comfort gain becomes.

Prefers is in the brake system, in which the embodiments described above the method according to the invention carried out be connected, the handbrake lever with the front wheel brake and the foot brake lever connected to the rear wheel brake circuit.

To accelerate the setting of the pump piston to the top dead center or to ensure safe, preferably a check valve with an additional leakage in at least one of Brake circuits used. Particularly preferably, the check valve, which is located on the pressure side of the corresponding pump piston, provided with a leak. The leakage is particularly preferably dimensioned so small that the (dynamic) delivery behavior of the pump is not or little influenced. Very particular preference, the check valve in the other brake circuit than the brake circuit, the pump piston is to be brought into the position at top dead center, used. Due to the existing leakage easier brake fluid from the wheel can get into the piston chamber of the corresponding pump piston and so the other pump piston is brought into the top dead center position.

According to one another preferred embodiment the method according to the invention The pump piston is thereby in the position at top dead center brought that in the other brake circuit than the brake circuit, whose Pump piston is to be brought into the position at top dead center, a higher one Wheel brake pressure level is set as in the brake circuit, whose Pump piston is to be brought into the position at top dead center. In conjunction with the inevitable, usually always present Leaks in the check valves, which are located on the pressure side of the pump piston, so in the brake circuit with the higher Brake pressure level of the pump piston by penetrating into the piston chamber brake fluid in the bottom dead center position moved, so that the pump piston of the other brake circuit in the Position is moved at top dead center.

Around to bring the pump piston into the position at top dead center, it is also preferable the wheel brake pressure in the other brake circuit as the brake circuit, the pump piston in the position at the top Dead center to be brought, slower than the wheel brake pressure in the brake circuit, the pump piston in the position at the top Dead center should be brought. This results in a higher brake pressure levels in the other brake circuit and the embodiments described above apply accordingly. The slowed brake pressure reduction becomes special preferably by a suitable control of a separating valve, which most preferably in the other brake circuit than the Brake circuit, the pump piston brought into position at top dead center should be located between brake lever and pressure side of the pump, carried out.

alternative It is to the pump piston to the position at top dead center bring, preferably, that the wheel brake pressure in the brake circuit, whose Pump piston are brought into the position at top dead center should, is degraded faster than the wheel brake pressure in the other Brake circuit. Also by this leaves a higher one Achieve brake pressure levels in the other brake circuit.

According to one another preferred embodiment the method according to the invention The pump piston is thereby in the position at top dead center brought that on the suction side of the other pump piston for a given Time a pressure is built or created, which is particularly is preferably held until the operation of the brake actuator completely by the driver finished.

Prefers To build or apply the pressure, a valve in the associated brake circuit short open, the pressure for held for a predetermined period of time and then reduced the pressure again. The opening the valve is advantageously during the termination of the operation of the Brake operating member carried out. By adjusting the time to hold the Pressure, it is ensured that the pump piston is on the Has moved position at top dead center. Particularly preferred For pressure build-up an exhaust valve is actuated briefly, which is between the wheel brake and suction side of the pump is arranged. For pressure reduction is special preferably a switching valve used, which between suction side arranged the pump and brake actuator is, or the pressure is over an exhaust valve, which between wheel brake and suction side of the Pump is arranged, an inlet valve, which is between wheel brake and pressure side of the pump is arranged, and a separating valve, which between brake actuator and pressure side of the pump is located, dismantled.

One Advantage of the invention is the minimization of disturbing reactions on an actuated Brake lever when starting the pump. Furthermore, the inventive method offers the Advantage, the pump piston of a not manually operated brake circuit vorzubefüllen. This will be the next active pressure build-up in this brake circuit improves, as immediately brake fluid be encouraged can.

The The invention also relates to a vehicle brake system in which a method described above is performed.

Further preferred embodiments The invention will become apparent from the dependent claims and the following Description based on figures.

It demonstrate

1 schematically a Teilintegralbrems installation of a motorcycle for carrying out a method according to the invention, and

2 schematically a full integral brake system of a motorcycle for carrying out a method according to the invention.

The inventive method is based on a motorcycle brake system with partial integral braking function (see 1 ), but it can also in any other Bremsan position, the two brake circuits and a dual-circuit piston pump, in particular radial piston pump, for supplying hydraulic pressure in the two brake circuits, are performed. For example, the method may be used in a motorcycle full integral brake system (see 2 ) or in a passenger car brake system.

In 1 a partial integral brake system for a motorcycle is shown schematically. This consists of two brake circuits 1 . 2 , one for the front wheel VR and one for the rear wheel HR, each with a master cylinder 3 . 4 , With a handbrake lever 5 the driver directly actuates the front brake 6 and with a foot pedal 7 becomes the rear wheel brake 8th actuated.

For brake slip control are both in the front and rear brake circuit 1 . 2 Electromagnetically actuated inlet and outlet valves 9 . 10 arranged, each with an open in the basic position inlet valve 9 in the brake line of the front and the rear wheel brake circuit 1 . 2 is used, which is the respectively associated master cylinder 3 . 4 with the front or rear brake 6 . 8th combines. In the rear wheel brake circuit 2 There is also an opening in the basic position isolation valve 11 , The outlet valve closed in basic position 10 is in each case in a return line 12 used by each brake circuit, which the front or rear brake 6 . 8th each with a low-pressure accumulator 13 and the suction path 14 a two-circuit split pump 15 which works on the return flow principle. The pump 15 is on the pressure side with the brake lines 16 Both brake circuits in conjunction, so that in a brake slip control phase a needs-based return promotion of each of the front or rear brake 6 . 8th drained brake fluid volume in the brake lines 16 is guaranteed both brake circuits. The pump pistons of the two pump circuits are shared by an electric motor 17 driven.

Both brake circuits 1 . 2 are operated according to their circuit design together and independently, with the peculiarity that with a manual operation of the front wheel brake 1 connected master cylinder 3 not just a brake pressure build-up in the front brake 6 , but at the same time also an electro-hydraulic brake pressure build-up in the rear wheel brake 8th done by the electric motor 17 the pump 15 puts into operation as soon as a result of the rear wheel brake circuit 2 electrically initiated open position of the switching valve 18 the pump 15 Pressure medium from the master cylinder 4 takes off and to the rear brake 8th promotes while the isolation valve 11 in the rear wheel brake circuit 2 the pump pressure side of the master cylinder 4 separates.

At the in 2 shown full integral brake systems in which the front wheel brake 1' according to the rear wheel brake circuit 2 (with compared to partial integral brake system off 1 additional isolation valve 11 and changeover valve 18 ), the aforesaid operation example can be reversed by depending on the manual operation of the rear wheel brake 2 connected master cylinder 4 according to the same scheme an electrohydraulically initiated braking on the front brake 6 is triggered. It follows that for the full integral brake system off 2 upon actuation of one of the two master brake cylinders 3 . 4 each of the driver not operated brake circuit quasi electro-hydraulic fremdange controls by the dual-circuit pump 15 is pressurized so that when a single operation of one of the two master cylinder always both brake circuits actively contribute to braking deceleration.

For the detection of the main brake cylinders 3 . 4 in the brake circuits 1 . 2 Injected pressures are usually pressure sensors 19 used. For the analogue control of the intake valves 9 can the brake circuits 1 . 2 additionally with a wheel brake pressure sensing pressure sensors 19 be provided. To evaluate the pressure sensor signals is a logic circuit in an electronic control unit 20 provided (in 1 not shown) in which depending on the evaluation result of the pressure sensor signals by means of the electrically actuated pump 15 a hydraulic pressure is generated.

According to the above statements is in the exemplary motorcycle brake system with partial integral function (see 1 ) upon actuation of the handbrake lever 5 the brake pressure level on the not manually braked by the driver wheel, the rear wheel HR, via a (eg in the electronic control unit 20 ) Defined brake force distribution determined and it is active, a corresponding brake pressure in the rear wheel brake 2 be controlled. This is done with the separating and exhaust valve closed 11 . 10 through the pump 15 Brake fluid from the master cylinder 4 over the opened changeover and inlet valve 18 . 9 to the rear wheel brake 8th promoted.

To illustrate a first embodiment of the method according to the invention is the exemplary partial integral system 1 considered. In the partial integral brake system, it is defined which brake is actively pressurized (in the case described, the rear wheel brake 2 ) or which brake actuating element (in this case, the hand brake lever 5 ) is to be decoupled from disturbing influences. The basic hydraulic consideration for this is that on the pressure side of the pump 15 arranged pressure valve 21 always has a certain leakage (leakage), or the pressure valve 21 that in the circle 2 is arranged, the handbrake lever 5 can not be assigned, even a small leakage can be structurally impressed. However, this leakage is to be provided in such a way that it is intended for pump delivery 15 does not matter, because here the dynamic pumping 15 the leakage exceeds many times.

By the exemplary method, it should be achieved, the pump 15 (more precisely: the pump piston) in the front wheel brake circuit 1 into an OT (top dead center) position in order to reduce the dead volume to an absolute minimum. This is, for example, by a targeted asymmetric pressure setting in the brake circuits 1 . 2 reached.

The driver presses the handbrake lever 5 (For example, the front wheel VR is assigned), so the pressure is built up by the integral function on the rear wheel HR active. The integral pressure build-up is based on a stored characteristic that can be vehicle-specific. Until the release process by the driver, the pressure in the rear brake remains 2 ,

The driver begins the release process of the handbrake lever 5 , so starts a special control mode. It is provided that the pressure reduction at the front wheel VR is faster than the reduction in pressure on the rear rear wheel HR, with the entire degradation gradient based on the release behavior of the driver and the driver no "sticking" of the brake notices A faster pressure reduction on the front wheel VR can eg be realized by a timed control of the respective valves of the respective brake circuit When the driver the pre-pressure on the handbrake lever 5 reduced, so for example only a little later the isolation valve 11 of the rear wheel brake circuit 2 opened and thus achieved that when the front wheel brake 1 already reached zero bar, in the rear wheel brake circuit 2 still a few bar pressure apply.

The asymmetric pressure reduction with excessive brake pressure level at the rear axle causes the following: Due to the existing leakage at the pressure valve 21 ("Unintentionally" or structurally conditioned (additional)), volume flows from the wheel brake into the piston chamber of the pump Since the pistons assigned to the two brake circuits sit on an eccentric, the piston is subjected to the higher pressure (in the example of the piston of the rear wheel brake circuit), begin to press the eccentric into the BDC (bottom dead center) position, but this also means that the piston of the other, lower pressure circuit (in the example of the front brake piston) is in the TDC (upper dead center This ensures a minimum dead volume in the front wheel brake pump piston, which can thus produce only a minimal hand lever back-up at the next braking.

A second embodiment to the pump 15 (the pump piston) of the front wheel circuit 1 It is to set the pump rotation by a Druckbe aufschlagung means of the exhaust valve to TDC (top dead center) 10 to create. This is when releasing the handbrake 5 the outlet valve 10 of the rear wheel brake circuit 2 pressed briefly, causing a pressure build-up before the non-actuated changeover valve 18 entails. Does the driver have the brake? 5 now completely solved (the residual pressure of the rear wheel circle 2 is usually via the isolation valve 11 degraded), then causes the caged pressure on the suction side of the pump 15 (the pump piston) in the rear wheel circle 2 also turn to UT (bottom dead center) as the system tries to relax. An advantage of this embodiment is that the pressure can eventually be kept longer, which makes the pump rotation to TDC (top dead center) safer. If a predetermined time has elapsed, the pressure that is still present in front of the pump, eg via a change-over valve, will be reached 18 reduced. Alternatively, the pressure may also be via outlet valve 10 , Inlet valve 9 and isolation valve 11 be reduced.

An advantage of both embodiments is the pre-filled pump 15 of the rear wheel circle 2 , which improves the next active pressure build-up.

For fully integral brake systems (eg 2 ), the circuit in which pressure can be actively built can not be predetermined. It is therefore conceivable, for example, a learning algorithm, which detects the brake circuit preferably operated by the driver by statistical evaluation, and assigns the inventive method with the setting of the pump piston in a position at top dead center of this brake circuit. Alternatively, the inventive method, for example, even in a fully integral brake system "fixed" the handbrake lever 5 be assigned because the driver there feels the un wanted return funding of a dead volume as particularly disturbing.

in principle is the procedure also with the piston pumps of the car applications conceivable to achieve comfort improvements or about pre-filled pump conditions.

Claims (9)

Method, which in a vehicle brake system, in particular a motorcycle integral brake system, with two brake circuits ( 1 . 2 ), at least one brake actuation element ( 5 . 7 ), a dual-circuit engine-piston pump unit ( 17 . 15 ) for pressure medium conveying or for pressure increase and non-return valves ( 21 ) and electromagnetically actuated by an electronic controller valves ( 9 . 10 . 11 . 18 ), characterized in that at least a part of the valves ( 21 . 11 . 10 ) is designed and / or controlled such that the pump piston of a brake circuit ( 1 ) during or after completion of an operation of the brake operating member ( 5 ) is brought into a position at top dead center. Method according to Claim 1, characterized in that the brake actuating element ( 5 ) with only one brake circuit ( 1 ) is hydraulically connected, and that the pump piston of the brake circuit ( 1 ), which with the brake actuator ( 5 ) is hydraulically connected, is brought into a position at top dead center. Method according to Claim 1 or 2, characterized in that the vehicle brake system has a hand brake lever ( 5 ), which only with one of the two brake circuits ( 1 ), in particular the front wheel brake circuit, is hydraulically connected, and a footbrake lever ( 7 ), which only with the other brake circuit ( 2 ) is hydraulically connected comprises, and - that, in particular during or after completion of the operation of the handbrake lever ( 5 ), the pump piston of that brake circuit ( 1 ) is brought into a position at top dead center, which with the handbrake lever ( 5 ), or - that is taught which brake lever ( 5 . 7 ) the driver is actuated more frequently, and that the pump piston of that brake circuit ( 1 . 2 ) is brought into a position at top dead center, which with the more frequently actuated brake lever ( 5 . 7 ) connected is. Method according to at least one of claims 1 to 3, characterized in that the pump piston by using a check valve ( 21 ) with a leakage in at least one of the brake circuits, in particular in the other brake circuit ( 2 ) is brought as the brake circuit whose pump piston is to be brought into the position at top dead center, in the position at top dead center. Method according to at least one of claims 1 to 4, characterized in that the pump piston is thereby brought into the position at the top dead center that in the other brake circuit ( 2 ) as the brake circuit whose pump piston is to be brought into the position at top dead center, a higher wheel brake pressure level is set than in the brake circuit ( 1 ), whose pump piston is to be brought into the position at top dead center. Method according to at least one of claims 1 to 5, characterized in that the wheel brake pressure in the other brake circuit ( 2 ) than the brake circuit whose Pum penkolben is to be brought into the position at the top dead center, is degraded more slowly, in particular by suitable control of a separating valve ( 11 ) than the wheel brake pressure in the brake circuit ( 1 ), whose pump piston is to be brought into the position at top dead center, or that the wheel brake pressure in the brake circuit ( 1 ), whose pump piston is to be brought into the position at top dead center, is degraded faster than the wheel brake pressure in the other brake circuit ( 2 ). Method according to at least one of claims 1 to 4, characterized in that the pump piston thereby in the Position is brought at top dead center, that on the suction side of the other pump piston for a predetermined period of time a pressure is built up. A method according to claim 7, characterized in that to build up the pressure, a valve, in particular the outlet valve ( 10 ), in the associated brake circuit ( 2 ), in particular during the termination of the actuation of the brake actuation element ( 5 ), is opened briefly, the pressure is maintained for a predetermined period of time and then the pressure is reduced again, in particular via a changeover valve ( 18 ) or via an outlet valve ( 10 ), an inlet valve ( 9 ) and a separating valve ( 11 ). Vehicle brake system, in particular motorcycle integral brake system, characterized in that in this a method according to a the claims 1 to 8 performed becomes.