Brake System with Electromotively Driven Piston/Cylinder System

• US 20100026083A1
• Filed: 04/20/2006
• Published: 02/04/2010
• Est. Priority Date: 04/21/2005
• Status: Active Grant

• Current Assignee: IPGATE AG
• Original Assignee: Wolfram Gerber
• Inventors: Leiber, Thomas, Leiber, Heinz
• Granted Patent: US 8,371,661 B2
• Time in Patent Office: Days
• US Class Current: 303/3
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/266 using valves or actuators with external control means B60T8/261 takes precedence
• CPC Class Codes: B60T 8/268 using the valves of an ABS, ASR or ESP system
• CPC Class Codes: B60T 8/4077 Systems in which the booster is used as an auxiliary pressure source
• CPC Class Codes: B60T 8/44 co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device , i.e. open systems

Abstract

The invention relates to a brake system which comprises an actuating device (26), especially a brake pedal (30), and a control/regulation device (22). Said control/regulation device (22) controls an electromotive drive device (8) in response to the movement and/or position (38) of the actuating device (30). The drive device (8) adjusts a piston (1) of a piston/cylinder system via a non-hydraulic transmission device (6), thereby adjusting a pressure in the working compartment (4′) of the cylinder (4). Said working compartment (4′) is connected to a wheel brake (15, 17) via a pressure conduit (13). In case of drive device (8) failure, the actuating device (26) adjusts the piston (1) or the drive device (8).

Claims

1. A brake system comprising an actuating device, in particular a brake pedal, and a control and regulating device, the control and regulating device controlling an electromotive drive device using the movement and/or position of the actuating device, the drive device adjusting a piston of a piston-cylinder system via a non-hydraulic gearing device, so a pressure is adjusted in the working chamber of the cylinder, the working chamber being connected to a wheel brake by a pressure line, characterized in that in the case of failure of the drive device, the actuating device adjusts the piston (1) or the drive device.

2. The brake system according to claim 1, wherein a sensor device determines the position of the actuating device.

3. The brake system according to claim 1, wherein a device, in particular a haptic device, for presetting or adjusting a force/travel characteristic of the actuating device is actively connected thereto.

4. The brake system according to claim 1, wherein a valve controlled by the control and regulating device is arranged in the pressure line to the wheel brake.

5. The brake system according to claim 4, wherein after achieving the required braking pressure in the brake cylinder the valve closes and is opened to adjust a new brake pressure.

6. The brake system according to claim 1, wherein the piston generates the required change in pressure for power-assisted braking (PAB) and the anti-lock braking system (ABS)

7. The brake system according to claim 1, wherein a spring loads the piston or the drive device with force, the spring force acting in a direction such that the working chamber is enlarged.

8. The brake system according to claim 1, wherein the drive device comprises at least one electric motor with a particularly small time constant and/or a large acceleration capacity.

9. The brake system according to claim 8, wherein when the valve is closed the electric motor is supplied with an exciting current which is sufficient to keep the piston in position against the spring force.

10. The brake system according to claim 1, wherein each brake circuit comprises a piston-cylinder system.

11. The brake system according to claim 1, wherein the working chamber is connected to a plurality of brake cylinders via two or more pressure lines, a respective valve being arranged in each pressure line.

12. The brake system according to claim 1, wherein the valve is a 2/2-way valve.

13. The brake system according to claim 1, wherein the piston-cylinder system comprises first and second pistons which are axially displaceably arranged in a cylinder, the first piston being mechanically coupled to the electromotive drive device and the second piston being hydraulically coupled to the first piston, the two pistons between them forming a working chamber which is connected to at least one brake cylinder by at least one pressure line, and the second piston, with the cylinder, forming a second working chamber which is connected to at least one further brake cylinder by at least one further pressure line.

14. The brake system according to claim 13, wherein valves controlled by the control and regulating device, in particular 2/2-way valves, are arranged in the pressure lines.

15. The brake system according to claim 13, wherein the brake system comprises a pressure transducer or pressure sensor for detecting the pressure in one of the two brake circuits or their pressure lines, in particular in the primary brake circuit.

16. The brake system according to claim 15, wherein the controller uses the pressure transducer to adjust the brake pressures for the two brake circuits.

17. The brake system according to claim 1, wherein when generating power-assisted braking the actuating device is not mechanically connected, or not directly mechanically connected, to the piston or the drive device, and only in the case of failure of the drive device or activation of the ABS is the piston mechanically connected to the actuating device.

18. The brake system according to claim 1, wherein two piston-cylinder systems, each with associated drive device, are arranged side by side, in particular parallel to each other, the actuating device adjusting at least one of the two pistons directly or via inserted means in the case of failure of at least one drive device.

19. The brake system according to claim 18, wherein the actuating device adjusts a lever or the pivot of a rocker parallel to the adjustment travel of the piston of the piston-cylinder system, and each free end of an arm of the rocker is associated with a respective piston.

20. The brake system according to claim 19, wherein a limiting element limits the swivelling range of the rocker.

21. The brake system according to claim 18, wherein the rocker is mounted on a piston which is displaceably mounted in a cylinder parallel to the piston driven by the drives, the piston being pressurized by means of at least one, in particular non-linear, spring in the direction of the brake pedal, and the spring, together with the piston, forming what is known as a travel simulator, and a sensor determining the position of the piston.

22. The brake system according to claim 21, wherein the piston stroke of the piston connected to the rocker is limited by a stop, it being possible to turn off the stop via an, in particular, electromagnetic final control element.

23. The brake system according to claim 1, wherein a channel of the working chamber of the piston-cylinder unit is connected to a reservoir, the piston closing the channel when retracted into the cylinder and the channel being opened in the starting position, i.e. only when the piston is almost or completely reversed.

24. The brake system according to claim 23, wherein a shutoff valve, in particular a 2/2-way valve, is arranged in the channel.

25. The brake system according to claim 24, wherein when the piston is quickly reset, the seal of the piston does not snift liquid from the reservoir owing to the vacuum in the working chamber.

26. The brake system according to claim 1, wherein the driven drives a toothed rack which is mounted parallel to the adjustment travel of the piston, in particular next to the piston, so as to be displaceable and in particular low in friction, the toothed rack being connected, in particular permanently connected, to the piston by a coupling member.

27. The brake system according to claim 26, wherein a spring pressurizes the coupling member or the toothed rack.

28. The brake system according to claim 1, wherein the controller adjusts corresponding power-assisted braking as a function of the movement and/or application of force of the brake pedal and/or the driving state and/or braking effect of an electric machine.

29. The brake system according to claim 1, wherein the controller determines the braking pressure in the working chamber of the cylinder from the driving current of the drive.

30. The brake system according to claim 1, wherein a pressure sensor is provided for determining the braking pressure in the working chamber of the cylinder.

31. The brake system according to claim 1, wherein the control and regulating device has a memory in which performance data with various parameters for controlling the drive is stored.

32. The brake system according to claim 1, wherein the controller determines the piston position by means of at least one sensor, in particular an incremental sensor of the electric motor.

33. The brake system according to claim 1, wherein the drive moves the piston out of the cylinder, so it is mechanically connected to the brake pedal and exerts a force on the brake pedal.

34. The brake system according to claim 1, wherein for generating a quick pressure reduction in the wheel brake before opening of the respective valve, the controller generates a vacuum by means of the associated piston by enlarging the working chamber.

35. The brake system according to claim 1, wherein for establishing an increased blocking pressure before opening of the respective valve, the control and regulating device supplies the electric motor of the drive device with approx. 120% of the preceding blocking pressure in the control cycle.

36. The brake system according to claim 1, wherein high-speed energy stores, in particular capacitors with a large capacity, are provided for storing electrical energy in order to generate pulsed currents.

37. The brake system, according to claim 1, wherein an additional drive adjusts the actuating device or the stop of the travel simulator in such a way that during normal operation the actuating device is not mechanically connected to the piston.

38. The brake system according to claim 37, wherein the additional drive acts on a travel simulator, in the case of a low blocking pressure the additional drive moving the travel simulator into the starting position during the pressure reduction in such a way that the actuating device is not mechanically connected to the piston.

39. The brake system according to claim 1, wherein the control and regulating device pre-excites the valve for fast closing, so the valve immediately closes as a result of a slight excitation intensification.

40. The brake system according to claim 1, wherein the drive device comprises at least one piston pivot lever by means of which the piston can be adjusted.

41. The brake system according to claim 40, wherein the piston pivot lever is a two-armed rocker arm.

42. The brake system according to claim 40, wherein the gearing is an encapsulated gearing and is incorporated in particular in the motor casing.

43. The brake system according to claim 1, wherein the piston is driven by means of a spindle drive arranged inside the rotor of an electric motor.

44. The brake system according to claim 43, wherein the rotor drives the piston via an axial nut that is displaceably mounted in the rotor, the nut being held in the axial position when the rotor is turned by a lever actuated in particular by means of an electromagnet and/or centrifugal force, and in the case of failure of the electric drive the spindle can be axially displaced in the rotor together with the nut.

45. The brake system according to claim 44, wherein the electromagnets are supplied with current via the motor control circuit by evaluating the rotor movement.

46. The brake system according to claim 44, the lever can be deflected by means of an electromagnet, the electromagnet comprising a radially or axially encompassing yoke for the armature of the lever.

47. The brake system according to claim 43, wherein the spindle is prevented from twisting by two bearing pins outside of the piston which also receive the piston restoring springs.

48. The brake system according to claim 43, wherein a torsion spring resets the motor.

49. The brake system according to claim 1, wherein the brake system adjusts a boost proportional to the pedal force, the brake system determining the pedal force at the, piston.

50. The brake system according to claim 1, wherein a damping element, in particular in the form of a leaf spring, is arranged between the actuating device and the respective piston, the leaf spring being arranged on the rocker in particular, and in that a force and/or proximity sensor for pedal force measurement is arranged on the rocker or the damping element.

51. The brake system according to claim 1, wherein a channel connects the working chamber to the reservoir, in which a safety valve is arranged which opens in the event of a jamming piston and connects the working chamber to the reservoir to reduce the pressure in the working chamber.

52. The brake system according to claim 51, wherein the safety valve is a mechanical-hydraulic or electromagnetic valve.

53. The brake system according to claim 1, wherein each brake circuit has a pressure modulating piston which is driven by a separate drive, it being possible to mechanically connect only one pressure modulating piston to the brake pedal.

54. The brake system according to claim 53, wherein the drives arid pressure modulating piston are arranged parallel to each other.

55. The brake system according to claim 1, wherein the pressure in the brake line can be determined by means of a pressure transducer or pressure sensor upstream of each solenoid valve of each brake circuit respectively.

56. The brake system according to claim 1, wherein a wheel, in particular a toothed wheel, is driven by the rotor, the wheel carrying a target which cooperates with an angle of rotation sensor to generate an angle of rotation signal.

57. The brake system according to claim 56, wherein the angle of rotation sensor is a Hall sensor.

58. The brake system according to claim 56, wherein a plurality of angle of rotation sensors are disposed to determine the drive position and/or pressure modulating piston position.