DE202006002734U1 - Device for wear monitoring of vehicle brake lining has arrangement for outputting or storing warning message if first or second wear parameter exceeds associated threshold - Google Patents

Abstract

The device has first and second arrangements for directly and indirectly detecting a first wear parameter while the vehicle is being operated, whereby the first wear parameter is determined independently of the second, and a third arrangement for outputting or storing a warning message if the first or second wear parameter exceeds an associated threshold.

Description

State of technology

The The invention is based on a device for detecting the wear at least a part of the components of a brake system of a vehicle the independent Claim.

By The strain on the brake system of a vehicle may be due to it from mechanical, electrochemical and / or electrical processes to one Wear of individual Components come. As an example of such subject to wear Components are motors, especially pump motors, mechanical Bellows for storing the hydraulic fluid and brake pads called. The occurring during use of the brake wear can for impairment the braking behavior and in extreme cases even a failure of the Systems lead. It is therefore desirable the wear of the Identify components to enable timely replacement.

From the DE 10 2005 060324 A1 For this purpose, a device for detecting the wear of the carbon brush drive of an electrically commutated DC motor is known, as used for example in the form of a pump motor in a motor vehicle. It can be concluded from the temporal behavior of the regenerative motor voltage on the wear of the carbon brushes. Another way to detect the abrasion of the carbon brushes of an electric motor is in the DE 10 2004 035318 A1 described. The wear is determined as a function of the speed of the electric motor.

From the DE 100 29 238 B4 On the other hand, a method for estimating brake lining wear in dependence on various operating parameters is known.

Advantages of invention

The The present invention describes an apparatus for detection of wear at least part of the components of a brake system in one Vehicle. In this case, means are provided in the device according to the invention two wear sizes independently determine. In addition to a first wear size, directly by physically measurable operating parameters of the monitored Components is detected, a second wear size is due Summed up the activation of the monitored components. It is provided in particular that the first and the second Wear size of the Wear the same Monitored components. additionally is another means provided which the two wear sizes with each predetermined thresholds and when exceeded sends a warning message to the driver or in a Memory stores.

to Determination of the first wear size in one first means is provided, the operating parameters one in the Brake components used to detect. It is conceivable here For example, the recording of the regenerative motor voltage or the current consumption required by the motor for operation from the vehicle electrical system. In addition, it is also conceivable, the pressure at various points of a hydraulic or pneumatic brake system, such as in the Store or in the wheel brakes. Furthermore, a consideration is the temporal behavior of the detected quantities possible, e.g. in the form of a gradient formation. Such a detection can impair the function of the monitored Components as a result of a change the operating parameters due to wear are detected.

In contrast, can the second wear size in the same or a separate means by the summation of the performed braking maneuvers, the Engine revolutions or the delivered brake fluid volume be determined indirectly. Also a consideration of activation of value-added functions in the context of brake system control conceivable to count on the wear of the monitored Close components.

Becomes exceeded one of the two thresholds, so this information can be used for later evaluation be stored in a suitable storage medium. It can be advantageously provided that for the two wear sizes respectively further thresholds are given and the storage from the transgression depends on further thresholds. This can advantageously differentiate the excess be reached by different thresholds. It is conceivable here e.g. that the registration of exceeding a first threshold the first wear size message merely serves to warn the driver about the wear of the monitored Informing components, whereas exceeding a third threshold results in an entry in a storage medium. Thus, at a read-out of the storage medium during a service stay in a workshop a further information about the state of wear the supervised Components are queried. This could be advantageous for example poorly accessible Be components of the brake system. Optional can also be provided be that any wear components own thresholds that indicate their wear.

In a development of the invention is quite generally provided that the further thresholds are below the first thresholds lie for the wear sizes. Optionally, it can also be provided that the exceeding of the first threshold values still no safety-critical wear of the components of the brake system represents.

Further Benefits emerge from the following description of exemplary embodiments or from the dependent ones Claims.

drawings

1 shows schematically the structure of a part of a brake system, in which the wear of at least one component to be detected. In 2 is shown on the basis of a block diagram, the independent determination of two wear sizes.

embodiment

The 1 schematically shows a hydraulic vehicle brake system 10 with a dual-circuit master cylinder 12 to which two independent brake circuits I and II are connected. For simplicity, however, only the brake circuit I is shown in the drawing 1, wherein the other brake circuit II is realized accordingly. It is expressly mentioned, however, that similarly equipped pneumatic vehicle brake systems or single-circuit brake systems can also be operated with the device according to the invention.

A branching main brake line 14 leads from the master cylinder 12 to two to the brake circuit 1 connected wheel brakes 15 and 16 , In the present embodiment, the two wheel brakes 15 and 16 associated with a front wheel and a diagonally opposite rear wheel of the associated vehicle, wherein the brake circuit II are assigned to the other two wheels. In addition to this so-called. X-brake circuit distribution, however, any other division of the brake circuits is conceivable.

In a common part of the main brake line 14 is between the master cylinder 12 and the pump 26 a changeover valve 18 arranged. Furthermore, in the branched parts of the main brake line 14 two inlet valves open in their normal position 20 and 21 arranged, each one of the wheel brakes 15 and 16 upstream. From the wheel brakes 15 and 16 performs a unifying return 22 in which for each of the two wheel brakes 15 and 16 a closed in its basic position exhaust valve 24 respectively. 25 is provided to the suction side of a hydraulic pump 26 , which can also be referred to as a return pump. In addition to the return line 22 a hydraulic accumulator 28 connected when the pump is switched off 26 and open exhaust valves 24 respectively. 25 Brake fluid from the wheel brakes 15 respectively. 16 can absorb, in the event that brake pressure is to be reduced. The pressure in the hydraulic accumulator 28 can be estimated or by means of a corresponding pressure sensor 50 be recorded. Optional is a pressure side of the hydraulic pump 26 via a damper chamber 30 and a throttle 32 between the switching valve 18 and the intake valves 20 and 21 to the main brake line 14 connected. Via a suction line 34 in which a in its basic position closed intake valve 36 is arranged, the suction side of the hydraulic pump 26 to a master cylinder 12 connected. With the help of a corresponding sensor 49 can the pressure in the master cylinder 12 are detected, which corresponds to the brake request of the driver by the operation of the brake pedal.

The hydraulic pumps 26 the illustrated and not shown brake circuit I or II, for example, a 6-piston pump can be driven by means of separate pump motors. In addition, however, is possible in a further embodiment, the pumps with a common electric pump motor 38 drive. The changeover valve 18 , the intake valves 20 and 21 , the exhaust valves 24 and 25 and the high pressure switching valve 36 are provided in the present embodiment as solenoid valves, including the anti-lock and traction control with an electronic control unit 40 are controllable. This controller 40 can also control the pump motor 38 take over and receive signals from Raddrehsensoren 42 and optionally at least one wheel pressure sensor 48 wherein the sensors for detecting a tendency to lock a vehicle wheel during braking or slipping when starting can be evaluated. Optionally, it can also be provided that each wheel brake 15 respectively. 16 one wheel pressure sensor each 47 respectively. 48 having. In addition, the controller receives 40 a signal from a brake pedal sensor (brake light switch) 44 , with which an actuation of the master cylinder 12 is detectable.

In a further embodiment of a brake system can also be provided that the pump 26 a high-pressure accumulator 60 filled, its pressure optionally by means of a pressure sensor 65 recorded or calculated using an estimation method.

To determine the wear of at least one component of the brake system is a unit 100 according to 2 provided, the example wise in the control unit 40 can be realized. In addition, however, is also a separate unit 100 conceivable. To independently determine the two wear sizes within the unit 100 to enable are separate subunits 110 and 120 provided, for example in the form of microprocessors that operate independently and thus independently. Optionally, it can also be provided that both subunits are operated by separate power supplies.

To detect a first wear size are in a first subunit 110 various parameters detected during operation of the brake system or the monitored components of the brake system. From corresponding measuring devices 150 respectively. 160 Thus, the regenerative motor voltage or the current absorbed by the motor can be detected. In addition, however, a recording of the wear of the bearing of the motor by the corresponding measuring devices is possible because the increase of the friction torque indirectly causes an increase in the motor current or a voltage drop at a shame by itself. Likewise, however, can also be detected by a speed drop, which is indicated by the reduction of the regenerative motor voltage, an increase in the friction torque.

Furthermore, sensors can 170 the memory pressure in the memories 28 respectively. 60 , the wheel brake pressure in the wheel brakes 15 respectively. 16 and / or detect the system pressure in the lines of the brake system. Thus, for example, it is conceivable to query at system startup of the vehicle or, the brake system, whether since the last operation, a discharge of the memory has taken place. Furthermore, the pump efficiency can be detected by determining the storage charge gradient or the wheel pressure gradient, in which, for example, the pressure increase per pump stroke or per unit time is detected. This can be done by means of a corresponding conversion in the unit 110 or in a separate external unit 180 respectively.

To calculate the second wear size is in a second subunit 120 takes into account the activation or the extent of activation of the brake system. It is from a corresponding institution 190 Information regarding the performed braking maneuver read. This information can be purely digital data on the activation of the brake system, but also the time exposure of the monitored components during activation. Furthermore, information about the revolutions of the engine can be read in, the one device 210 ready.

About the activation of the pump 220 can be concluded on the funded brake fluid volume and thus on the stress of the individual components. Finally, there is also the possibility to consider the activation of value-added functions in the framework of ABS or ESP regulations during the monitoring. Such activations may be for example from a separate unit 200 captured and sent to the second subunit 120 to get redirected.

The from the first subunit 110 generated first wear size and that of the second subunit 120 generated second wear size is sent to a processing unit 130 directed. In the processing unit 130 it is checked whether the first amount of wear exceeds a first threshold and / or the second amount of wear exceeds a second threshold. If at least one of the two threshold values is exceeded, the driver can use a corresponding warning device 250 be visually and / or acoustically informed about the impairment of the brake system. Due to this warning signal, the driver can then adjust his driving behavior or visit a workshop.

Optionally, it can also be provided that each wear quantity is compared with at least one further threshold value. For example, it may be provided that a third threshold value is provided for the first wear quantity, which is below the first threshold value and is thus exceeded earlier. The lower third threshold value can be selected such that the value of the wear quantity associated with this wear does not lead to any safety-critical impairment of the brake system. Accordingly, the second amount of wear may be assigned a fourth threshold, which is lower than the second threshold. However, in order to indicate wear to a service technician, it may be provided that the exceeding of such a further threshold value in a memory 140 , for example, also in the unit 100 can be accommodated, is stored. The service technician can then use a suitable interface 260 access this information and thus specifically exchange the affected components.

Farther is conceivable, each monitored components To assign each of the brake system two own wear sizes. The with these Wear variables associated Threshold values allow a clear identification of the components, the due to the wear need to be replaced.

In a further embodiment, it may also be provided that through the interface 260 an adjustment of the thresholds vorgenom can be, for example, after an exchange of components of the brake system with changed operating characteristics. The threshold values are first stored in the memory 140 from which the processing unit can read out the new threshold values as needed.

Claims (7)

Device for detecting the wear of at least part of the components of a brake system ( 10 ) in a vehicle, wherein it is provided that during operation of the vehicle - a first means ( 110 ) records directly a first amount of wear and - a second means ( 120 ) indirectly calculated a second wear size, wherein it is provided that - the first wear size is determined independently of the second wear size. and - a third remedy ( 250 ) is provided which outputs or stores a warning message when - the first amount of wear exceeds a first threshold or - the second amount of wear exceeds a second threshold. Wear detection device according to claim 1, characterized in that the first means directly measures the first amount of wear as a function of the detection - of the regenerative motor voltage of an engine ( 38 ) or - the current consumption of the motor or - the accumulator pressure in a pneumatic or hydraulic accumulator ( 28 . 60 ) or - the system pressure in the brake system ( 10 ) or - the storage charge gradient or - the Raddruckgradienten determined. Device for detecting the wear after Claim 1, characterized in that the second means the second Wear size indirect dependent on from - the conducted braking maneuvers of the vehicle, or - of the Activation of value added functions, or - Engine revolutions, in particular pump motor turns, or - The pumped volume of brake fluid calculated. Device for detecting wear according to claim 1, characterized in that a fourth means ( 140 ) is provided which stores the exceeding of a third threshold value by the first wear amount or the exceeding of a fourth threshold value by the second amount of wear. Device according to claim 4, characterized in that that the third threshold is lower than the first threshold and the fourth threshold lower than the second threshold is given. Apparatus according to claim 4, characterized in that the fourth means by a corresponding device ( 260 ), wherein it is provided in particular that it can be concluded from the exceeding of one or both threshold values to the components which has a predetermined wear. Device according to claim 1, characterized in that that crossing of the first or second threshold is not safety-critical Wear the Brake system represents.