WO2009138252A1

WO2009138252A1 - Electric parking brake that can be actuated using the brake pedal

Info

Publication number: WO2009138252A1
Application number: PCT/EP2009/003519
Authority: WO
Inventors: Heinz Leiber
Original assignee: Ipgate Ag
Priority date: 2008-05-16
Filing date: 2009-05-18
Publication date: 2009-11-19
Also published as: DE102008024019A1

Abstract

The invention relates to a parking brake comprising a hydraulically adjustable piston (101) that acts on at least one brake lining and can be locked in the parked position by means of a locking mechanism. A control device (11) controls the parking brake (8, 8e) and the components additionally required for activating and deactivating the parking brake, the parking brake (8, 8a) being activated by actuating the brake pedal (1).

Description

Applicant:

IPGATE AG Toblerstrasse 76a CH-8044 Zurich Switzerland

Description :

Brake pedal activatable electric parking brake

The present invention relates to a parking brake, with a hydraulically adjustable piston, which acts on at least one brake pad, wherein the piston can be locked in the Parkierstellung by means of a locking device, wherein a control device the parking brake and additionally required for the activation and deactivation of the Parkierbremse Controls components.

Electric parking brakes are known and are used in particular for better comfort. There are electric parking brakes with electric motor and gear known, the transmission acts on a brake piston. This solution is technically complex and expensive and disadvantageously has a high weight. In addition, electric Parkierbremsen are known in which an electric geared motor tensioned a cable mainly for Scheiben- with integrated drum brake.

Furthermore, electric parking brakes are known from DE 103 20 907 and DE 10 2007 015 809. In these parking brakes is the Used pressure support of a brake device, which supplies the parking brake with their activation with pressure. Here, the brake piston parking brake is held firmly by a motor with spindle drive, so that when the brake device is deactivated, the clamping force of the piston is maintained. These concepts are much easier and easier. They have not found any application until now, since the parking brake fails in case of failure of the pressure generation, whereby a security deficiency is given. As a pressure transmitter, a vacuum brake booster is usually used, which can generate a corresponding pressure in the master cylinder via an electromagnetic valve by a chamber is supplied with atmospheric pressure. If this valve fails, no parking brake can be activated. If the vacuum fails, z. B. at a longer downtime, the parking brake can not be disabled, ie not be solved. On the other hand, pressure can also be generated via the ESP hydraulic unit via the electromotive pump with appropriate valve circuit. In case of failure of the electric motor or the valves but no parking brake can be activated. In an electromotive brake booster according to DE 100 2005 018 649 falls in case of failure z. B. the electric motor also from the parking brake. Be switched above electrical parking brakes on a switch on the dashboard or automatically, z. B. at vehicle standstill.

The invention is therefore based on the object to provide a parking brake, in which an activation of the parking brake can be carried out with simple means and optionally also in case of failure of the amplifier to generate pressure.

This object is achieved according to the invention that the parking brake by using the already existing

Brake pedal is activated. Further advantageous embodiments of the parking brake according to claim 1 are obtained by the

Features of the dependent claims. By simply using the

Brake pedal according to the invention the parking brake is activated. This activation may vary depending on the vehicle speed. and / or also the inclination angle of the vehicle. Thus, the control device can be programmed such that, when the vehicle speed approaches zero, the control device activates the parking brake when the brake pedal is actuated. Likewise, a dependence of the selector lever can be taken into account in an automatic transmission. For example, when switching the selector lever in the park position, the parking brake can be activated, at the same time the brake pedal is printed, if not the fully automatic function is turned on. The control device can also be programmed such that the parking brake is only activated when the brake pedal has been actuated for a predetermined time when the vehicle is stationary.

The necessary brake pressure of the parking brake can advantageously be a fixed value. However, it is particularly advantageous if the necessary brake pressure is determined and predefined based on the measured data of an inclination sensor, wherein the inclination sensor can anyway be present as an acceleration sensor in the ESP system.

In an advantageous further embodiment of the invention, a display and / or an audible warning device is used to indicate to the driver when the required brake pressure for the parking position is not reached. The driver then has to press the brake pedal to build up the necessary activation pressure.

So that the required brake pressure can be built up by actuation of the brake pedal in the event of failure of the electric motor or of another pressure generator, it is necessary that the brake pedal is mechanically and / or hydraulically connected to the piston of the parking brake and the piston to brake pressure build-up Actuation of the brake pedal adjusted. Thus, the force required to operate the brake pedal is not too large, so that possibly weaker people can not build the necessary brake pressure, it is advantageous if a pressure interrupter between the piston and the brake pedal is arranged. It will be here In particular, a simple plunger proposed as a pressure interrupter, which can reduce the Fußkrafte for generating higher pressures, in particular with a steep slope or gradient by a factor of 2 to 3.

In addition to the possible failure of the electric motor, which is used to generate pressure, the electrical system may fail in case of power failure. Without this, the vehicle, d. H. Motor, light can not be operated. Critical, however, is the failure of the generator while driving, here is an emergency until the empty battery. In this limiting case, the internal combustion engine fails if the battery can no longer provide the power for supplying the ignition, injection and tank pump with about 10 A, which then causes the vehicle to be shut down. An advantage of the solution according to DE 10 2007 015 809 is additionally that the current strengths for the electric motor of the parking brake with about 2 A is small. This small current strength can still deliver the battery, even if the engine is already stopped, so that the function of the parking brake is still possible.

The proposed solution has additional advantages in addition to the aforementioned advantages in case of failure of the electromotive pressure generation or the electrical system. So fewer controls and cables are needed. The necessary pressure transducer for the invention,

The pedal travel sensor and brake light switch are already present in the vehicle through the existing ESP system. In addition, the parking brake according to the invention is considerably more cost and weight-saving than the electromotive parking brakes known from the prior art and has the potential, up to the present

To find small car application. Furthermore, the entire

Functions fully diagnosable. An automatic parking brake function for e.g. Parking, starting and stop-and-go can be optionally switched on as an option.

In accordance with the applicable regulations, an additional control element must be present next to the brake pedal sensor or switch for activating or deactivating the parking brake. In Usually, an additional switch is provided here, which is placed in the center console, for example. This means an additional effort for installation and wiring. Instead of the additional switch, an additional redundant brake pedal sensor or switch with separate operation, ie coupling to the pedal is proposed. The implementation is particularly possible with an integrated brake system, as described in DE 102005018649, since the internal wiring can be integrated for the redundant sensor or switch. In addition to the activation of the parking brake on the redundant sensor or switch, it is within the meaning of the invention that a fully automatic activation and deactivation without the driver. Switch and display are essentially only necessary if an error, such as failure of the electric brake booster occurs.

The invention is explained in more detail with reference to drawings.

Show it:

1 shows a block diagram of all components required for the parking brake according to the invention;

Fig. Ia: electro-hydraulic parking brake according to the prior art;

2 shows a block diagram of all components required for the parking brake according to the invention with diagonal brake circuit distribution;

Fig. 3: Scheme for the functions of the parking brake according to the invention.

FIG. 1 shows the essential components of the parking brake according to the invention involved in the function. To activate the parking brake, the driver actuates the brake pedal, which is sensed by a pedal travel sensor or brake light switch 2. In a system according to DE 100 2005 018 649.1, the electromotive Brake booster 3 turned on, then z. B. at vehicle standstill automatically a target pressure of z. B. 100 bar and measured by the pressure transducer 9. The pressure from the master cylinder 4 passes through the brake lines 16 and 17 and control valves 5 to the wheel brakes 6, 6a, 7, 7a. If the target pressure is reached, the control unit 11 switches the electric motor of the electric parking brake and the pressure is reduced to zero. If the process is completed, the amplifier 3 is switched off again.

Fully redundant to the pedal travel sensor or switch 2, a second sensor or switch 2a is provided to meet the legal requirements and to increase the safety of the function of the electric parking brake.

The function of actuation and release of the electric parking brake will be explained below with reference to FIG. 1a, which is described in more detail in DE 10 2007 015 809.4.

Fig. Ia shows the overall construction of brake caliper 102 with brake piston 101 and actuator. Known details such as construction of the brake, brake pad and seals are not described. About the pressure line 125 is controlled by the brake pressure during parking, as shown in detail with reference to Figures 3 and 4 and described in more detail later. The brake piston 101 prints on the brake pad, not described, simultaneously or with a time delay moves the rotor 113 via the pin coupling 113a, the spindle 103, which transmits the force on the movable pressure plate 104 on the piston 101. The pressure is maintained at the level for a short time until, preferably, the spindle 103 stops moving, since it bears against the pressure plate 104. The movement of the spindle is detected by the rotation angle sensor of the rotor. After pressure reduction, the clamping force of the caliper 102 fully on the pressure plate 104 and spindle 103 acts on the flange with main spindle nut 107 and ejection nut 108. The one-piece main spindle nut 107 can also be replaced by two easier-to-manufacture parts 105 and 106, wherein part 106 a Flange, which cooperates with the ejector nut 108. The movable pressure plate 104 prevents large lateral forces on the threads 103c, 107a and jamming to realize minimum driving forces of the spindle operation. The spindle 103 and the rotor 113 are separated via a coupling 113 a, so that a radial offset of the spindle 103 and rotor 113 does not affect the rotor 113. Furthermore, the rotor 113 is axially fixed, whereby the Baulange is kept short. However, given the large travel path for the spindle 103, which is needed to account for brake pad wear, there is still a short overall length of the overall device. For this purpose, the spindle 103 has an extension 103a, which has a slot 103b extending in the axial direction. The separation of the rotor 113 and spindle 103 via the pin coupling 113 a reduces the heat transfer of the spindle 103, which is in contact with the hot brake piston 101.

The rotor 113 has slip rings 116 and 117 at both ends which move on the inner wall 112b of the bell 112. The Gleitstuck 117 additionally carries the target 119, z. B. a permanent magnet, for the rotary encoder 120, if, for example, the Hall principle is used. Both Gleitstucke 116, 117 are preferably shaped so that they fill the free air space in the example grooves and bore of the rotor to ensure good ventilation via a bleeder screw, not shown, which is arranged in the region of the highest spatial location for good ventilation. On the rotor 113, a torque from the magnetic flux of the stator of a brushless electric motor acts. All known principles such as asynchronous, synchronous or reluctance motors can be used here. The latter is preferred because of the simple construction and the high temperature load. As in the lower half of the picture, the stator can conventionally be constructed from pole plates 114 and winding head 114a. The magnetic flux passes through the non-magnetic bell 112 and at the same time separates the stator 114 from the high-pressure space of the rotor 113. In the upper half of the figure, a disk-shaped structure of the iron circle 115 is shown with coil 115a, which corresponds in the example shown, a 3-pole stator of the reluctance motor. This embodiment is advantageous when redundant windings are used, which can be easily listed here as a cylindrical coil. The stator laminations abut in both embodiments on the outer circumferential surface of the bell 112 in order to brace them at the high pressure load. In addition, a Abstutzring 12 a is still used at the end of the stator. Stator 114, 115 with winding 114a, 115 are injected together with the rotary encoder 120 and Abstutzring 112a in the housing 121. It is advisable to inject the ABS speed sensor as well in order to save a separate watertight plug-in connection and if necessary to use a common ground line with a rotary encoder. Here, all lines can be routed to the body via a separating clutch. Also eliminates a separate attachment of the line to the wheel carrier. The Statorgehause 121 is also encapsulated on the front side, so that a heat insulation to the bell 12 can be used.

As shown in Figure 1, the function of the electric parking brake may be displayed in a display 13, e.g. Of course, the instrument cluster previously used may also include a parking brake indicator 14. When the electric parking brake is activated, it is sufficient to direct the pressure into the wheel brakes with the parking brake, in which case the control valves 5 in front of the wheel brakes will be switched off Deactivation is carried out as described in the same way by using the brake pedal with intact amplifier 3 automatically the pressure level for switching off the parking brake is controlled or in case of failure via the foot force with appropriate notice on display or display the required pressure is generated Operation is similar to the mechanical Fußfeststellbremse.

In addition, the parking brake automatically activated at each vehicle standstill, especially after stopping the engine become. This offers possibilities that are possible via networking with the on-board network and the systems.

A display 13 in the display 12 may e.g. preferably be made in the instrument cluster. As an alternative, an optical or acoustic display or warning may be used. Furthermore, the display in another display z. B. head unit or radio to be made.

Figure 2 shows the same arrangement with components, this time for a brake system with diagonal brake circuit distribution. The function of the parking brake 8 and 8a is described with reference to Figures 1 and Ia. It is here omitted to explain the basic functions again. In the figure 2, the switching positions of the control valves 5a, 5b, 5c and 5d are shown. In addition, the electromagnetic 2/2-way switching valves 19 / 19a for the Druckübersetzer available. The positions of the valves 5a and 5b correspond to the positions during normal operation of a braking, in which the control valves 5a and 5b are open and temporarily closed during ABS operation. The switching valve 19 for the pressure interrupter is closed.

The lower half of the picture with the control valves 5c and 5d shows the parking function. Here, the control valve 5c for the brake 7, which has no parking brake, closed to receive no additional volume from the master cylinder 4 with corresponding pedal travel. The control valve 5d for the brake 7a is also closed. The switching valve 19a to the pressurizer 15a is open, causing the pressure generated by the brake pedal via the master cylinder 4 to be translated to the parking brake 8a in accordance with the areal ratio of the pistons of the pressurizer 15a. Since for the two parking brakes 8 and 8a less volume eg two instead of four brakes from the master cylinder is needed with acceptable pedal travel a ratio of 2 to 3 is possible, ie with relatively small pedal forces enough pressure can be generated. The switching of the pressure interrupter is only in case of failure of the amplifier 3, in case of failure of the motor drive or also necessary in case of failure of the above generator with almost empty battery. The battery can still muster at least the necessary energy for driving the display 13/14 to inform the driver due to the low power consumption even in case of failure of the internal combustion engine. The control functions for all electrical components are provided by the central control unit 11, which may include the function for ABS / ESP, electromotive brake booster and parking brake with pressure interrupter. Communication with the display 13/14 takes place via a bus line, eg CAN. The electrical connection lines 10 connect the control unit 11 with all electrical components of the system. Symbolically, the inclinometer 18 is shown here for calculating the necessary parking pressure, which may be obtained in ESP systems in the sensor cluster. In hybrid vehicles, the on-board network is additionally supported by a DC / DC converter.

The left half of Figure 3 shows the circuit 20 for all functions of the invention Parkierbremse. The right half of Figure 3 shows the automatic function of Parkierbremse.

The logic circuit 20 has the two operating states "apply" and "lots" of Parkierbremse. The logic circuit 20 differentiates between "normal case" and "Electromotive pressure generation failure". In the "normal case", the circuit 20 according to the left-hand half of FIG. 3 is active. In the case of a "failure of the electromotive pressure generation", the circuit 20 according to FIG. the right half of Figure 3 active.

In the "normal case" it is necessary for the tensioning of the electric parking brake, that the brake pedal 1 is operated with pedal encoder 2 and the engine is "off", eg via ignition "off" as AND condition preferably via evaluation of the speed v = 0 after a time, for example 1 s, with or without actuation of the brake pedal 1 initiates the clamping or in particular engages the stop-and-go system with full automatic, the engine stops and initiates the tensioning of the electric parking brake. This system works, for example, only when the engine is warm and has priority over the aforementioned sub-automatic circuit. For example, it is also possible to use only the stop-and-go circuit for clamping in addition to the described input commands 1/2 and motor "off." These voltage signals are then converted at the output for actuation of, for example, the electromotive brake booster 3, which controls either the pressure for the parking brake to a fixed value in accordance with the pressure signal 9 and / or takes into account the measured vehicle inclination by means of the inclination sensor a _L and accordingly sets a pressure to reduce the stress on the parking brakes 8 and 8a This function has already been described.

The logic signals of the brake pedal sensor or switch 2 and 2a have a redundant effect on the control when tensioning and releasing the parking brake.

As an alternative to the operation of the parking brake, the service brake can also be switched on via the brake booster 3, if the fully automatic circuit contains the stop-and-go function, because here only a relatively short time, e.g. at the traffic light stop, the parking position is used.

The "activation or tensioning" of the parking brake is displayed as conventionally in a control lamp 22. The automatic function 23 can also be displayed in parallel in the event of failure of the parking brake with the warning lamp 24 for "failure".

The parking brake is released by renewed brake pedal actuation. Furthermore, as an And condition, a switched on internal combustion engine is required, eg ignition "on" or accelerator pedal actuation α _G p, ie the parking brake can also be released when the vehicle is downhill without a running engine. and-Go, the engine starts to accelerate, of great importance for the operation comfort is the approach control. This contributes Au ^¬ tomatikgetriebe the engine torque MM and the transmission with a torque which is aligned with the lots of the parking brake on 8, 8a on the amplifier 3, preferably, the inclinometer is used with a _L here. In a manual transmission, the signal of the clutch sensor is additionally used. These processes are introduced in series and are not described separately.

When the AND circuit and the fully automatic circuit act as the tension command simultaneously, the full automatic circuit has

Priority. The driver can for the "cocking" and "loose" the

Press the brake pedal without disturbing the automatic transmission.

The process of "clamping" and "lots" is similar to that of the so-called.

Keyless go systems. For these, the brake pedal must be pressed to stop and switch on the engine.

The right half of Figure 3 shows the function of the parking brake in case of failure of the brake booster 3. By a diagnostic test at door opening or at the latest when Bremspedalbetatigung this is detected and the displays 25 and 26 preferably driven in the display. Upon actuation of the brake pedal 1 and pedal encoder 2 and additional engine shutdown or V = O, the brake pressure acts on the parking brake or it is activated. When the setpoint pressure 9 is reached via the pressure sensor 9 or alternatively via the position of the brake pedal, the display lamp for the parking brake is activated. Again, the signal of the inclinometer a _L can be used with, so only in the extreme case of parking on a slope high Fußkrafte be needed. The function of the parking brake 8 and 8a remains the same. The automatic circuit can not work for cocking because the electrical amplifier 3 is missing.

To loose, the same And logic is effective as in the left half of Fig. 3. In contrast to the "tensioning" here can be a simplified traction help especially for manual transmissions are used, since the simultaneous handling of clutch, brake and Accelerator pedal is difficult, as the experience with the Fußfeststellbremse shows. Here, for example, when releasing after reaching the release pressure the parking brake 8 / 8a unlocked, the pressure on the control valves 5b and 5d via the pressure transducer in coordination with the engine torque and speed and forward or backward movement controlled so that an automatic start on the mountain is possible ,

Operation of this parking brake is similar to "normal case" operation and in the rare case of "electromotive pressure generation failure", making it easy for the driver to use and understandable. It is much simpler than a normal remote control vehicle, keyless go systems or vehicles with or without automatic transmissions that require the brake to be applied to keyless go systems. Here he has to press the brake on all vehicles. For cost savings and ease of use can also be dispensed with the usual switch.

The present inventive concept is also fully effective and cost-effective in the described borderline cases. This allows use in all vehicle types.

Reference sign list

1 brake pedal

2 pedal or brake light switch

2a redundant brake pedal sensor or switch 3 brake booster

4 master brake cylinders with reservoir

5 control valves for pressure control ABS / ESP

6 Wheel brake 1 6a Wheel brake 2 7 Wheel brake 3

7a wheel brake 4

8 / 8a electromotive parking brake

9 pressure transmitter

10 electrical line 11 central control unit

12 instrument cluster or device with display

13 display

14 warning lamp

15 pressure interrupter 16 brake pipe 1

17 brake line 2

18 Inclinometer 19 / 19a 2/2 shift valves α _L Engine inclination sensor Off Engine management Off α _GP Accelerator pedal sensor

Engine On Engine Management On

Ku coupling sensor

V Vehicle (wheel) Speed To Ignition

T time base

20 logic circuit for margins / lots

21 logic circuit for automatic parking brake

22 Parking brake warning lamp clamped 23 Display for automatic function

24 Warning lamp for failure Parking brake

25 Display in case of failure of brake booster

26 Emergency function parking brake

Claims

claims

1. parking brake, with a hydraulically adjustable piston

(101) acting on at least one brake pad, wherein the

Piston (101) in the parking position by means of a

Locking device can be locked, wherein a control device (11) controls the parking brake (8, 8a) and the components additionally required for the activation and deactivation of the parking brake, as indicated by cha ting that by operating the brake pedal (1) the parking brake (8, 8a) is activated.

2. Parking brake according to claim 1, dadu rch gekenn z e i chne t that the activation takes place only when the vehicle is stationary, the engine is off or the vehicle speed goes to zero, in particular after a predetermined time interval.

3. parking brake according to claim 1 or 2, dadur ch ge kenn ze zeke that by means of the brake pedal (1), which in particular mechanically and / or hydraulically with the piston (101) of the parking brake (8, 8a) is in communication, a for the adjustment of the piston (101) of the parking brake required hydraulic pressure is buildable.

4. parking brake according to claim 3, characterized zei chne t that a signaling device (26) the (or) the driver (in) then gives an audible and / or visual signal when the required for the Parkierstellung pressure build-up without actuation of the brake pedal ( 1) can be done or the required pressure level is not reached.

5. Parking brake according to one of claims 1 to 4, dadur ch gekenn zei chne t that the brake pedal (1) is mechanically in communication with a pressure interrupter (3,4), wherein the working space of the pressure interrupter with at least one parking brake (8, 8a ).

6. parking brake according to one of claims 1 to 5, dadur ch gekenn zei chne t that the control device (11, 21) adjusts or regulates the braking force of the parking brake (8, 8a) in response to the signal of a tilt sensor (a _L ) of the vehicle ,

7. parking brake according to claim 6, characterized ge kenn z e i chne t that the control device (11, 21), the signal of the inclination sensor of the ESP control for adjusting or setting the braking force of the parking brake (8, 8a) used.

8. Parking brake according to one of the preceding claims, characterized in that the control device (11, 21) automatically activates at least one parking brake (8, 8a) of the vehicle during each vehicle standstill, in particular after the engine has been switched off.

9. Parking brake according to one of the preceding claims, dadu rch gekenn z e i chne t that in stop-and-go trips when the vehicle is stationary instead of the parking brake (8, 8a) of the brake booster generates the brake pressure.

10. Parking brake according to one of the preceding claims, dadu rch gekenn zei chne t that the control device (11, 21), the parking brake (8, 8a) is activated when the selector lever is set to the position "N" in an automatic transmission vehicle and the vehicle speed is zero or the vehicle speed approaches zero.

11. Parkierbremse according to any one of the preceding claims, characterized e e ee t that optionally by the Betatigen of the brake pedal (1) or an additional operating element, in particular a switch, the activation of the at least one parking brake (8, 8a) takes place.

12. Parking brake according to one of the preceding claims, characterized in that the brake system has two brake pedal sensors, brake pedal sensors or brake light switches (2,2a) or a combination thereof to achieve a required redundancy.

13. Parking brake according to one of the preceding claims, characterized in that the control device (11, 21) releases the at least one parking brake (8, 8a) if the engine torque (MM) is greater than the braking force of the parking brake or parking brake of all the parking brakes (8, 8a) is together and / or the vehicle speed is greater than zero and / or increasing.

14. Parking brake according to one of the preceding claims, characterized in that when the amplifier (3) fails in a manual transmission vehicle for releasing the parking brake, the signal of the Kupplungsnehmer- cylinder and the engine speed for the engine torque control is used.