Brake Actuation Unit

• US 20160009263A1
• Filed: 02/28/2014
• Published: 01/14/2016
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Feigel, Hans-Jrg, Kurbasa, Josko
• Granted Patent: US 10,131,333 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 11/103 in combination with other control devices conjoint control of brake system and at least another sub-unit B60W10/188
• CPC Class Codes: B60T 11/224 with pressure-varying means, e.g. with two stage operation provided by use of different piston diameters including continuous variation from one diameter to another
• CPC Class Codes: B60T 2270/82 Brake-by-Wire, EHB
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: B60T 8/321 deceleration B60T8/34, B60T8/52, B60T8/54, B60T8/56, B60T8/58, B60T8/72, B60T8/86, B60T8/88 take precedence
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence

Abstract

A brake actuation unit (I) having a master brake cylinder (2) and a pressure-medium reservoir (4); a pressure provision device (5), having a piston (51) actuated by an electric motor (35), wherein the piston delimits a pressure chamber (50); first and second groups of electrically actuatable valves (6a-6d, 7a-7d); and an electronic control unit (12, 12′). The electric motor has at least two independently operable drive units, each having at least one winding, for driving the electric motor. The electronic control unit has a first microcontroller (201) and a second microcontroller (301). The first microcontroller controls (205) one of the drive units and the second microcontroller controls (305) the other of the drive units. The first and second microcontrollers control (207, 307) the second group of valves.

Claims

1. A brake actuation unit for a brake-by-wire motor vehicle brake system for a motor vehicle comprising:

a brake-pedal actuatable master brake cylinder having at least one master brake cylinder pressure space to which hydraulically actuatable wheel brakes of the motor vehicle can be connected, a pressure medium reservoir vessel which is assigned to the master brake cylinder,

an electrically controllable pressure supply device which is formed by a hydraulic cylinder-piston arrangement having a piston actuated by an electric motor having a rotor and a stator, wherein the piston bounds a pressure space which is sealed with respect to the atmosphere by a first sealing element and which has a pressure medium connection for connecting to the wheel brakes, a first group of electrically actuatable valves for setting wheel-specific brake pressures,

a second group of electrically actuatable valves for disconnecting or connecting the wheel brakes from or to the master brake cylinder or from or to the pressure supply device,

an electronic control unit for activating the pressure supply device, the first group of valves, and the second group of valves, and

the hydraulic cylinder-piston arrangement configured such that after a predefined actuation displacement of the piston the pressure space is sealed by a second sealing element, in that the electric motor has at least a first and a second drive unit which can be operated independently of one another and each have at least one winding for driving the rotor of the electric motor, and in that the electronic control unit comprises a first microcontroller and a second microcontroller, wherein the first microcontroller is designed to activate the first drive unit of the electric motor, and the second microcontroller is designed to activate the second drive unit of the electric motor, and wherein the first and second the microcontrollers are designed to activate the second group of valves.

2. The brake actuation unit as claimed in claim 1, wherein the brake actuation unit further comprises a pedal travel simulator which gives a vehicle driver a pleasant brake pedal sensation in a brake-by-wire operating mode and which is embodied so as to be capable of being switched on and off by a simulator enabling valve, wherein the simulator enabling valve can also be activated by the first and the second microcontrollers.

3. The brake actuation unit as claimed in claim 1, wherein the pressure supply device further comprises a stepped bore arranged in the housing, and the piston is embodied as a stepped piston whose piston step with a smaller diameter fits into a smaller diameter portion of the stepped bore after the predefined actuation displacement of the stepped piston, with the result that the pressure space is divided into a first pressure space area at which the pressure medium connection is arranged, and a second pressure space area in the form of the an annular chamber.

4. The brake actuation unit as claimed in claim 3, further comprising in that in a state of the piston displaced beyond the predetermined actuation displacement the piston step the first pressure space area and the second pressure space area are sealed with respect to one another by the additional sealing element.

5. The brake actuation unit as claimed in claim 1 further comprising in that the first group of valves can be activated only by the first microcontroller, wherein the first group of valves comprises one inlet valve and one outlet valve for each of the wheel brakes.

6. The brake actuation unit as claimed in claim 5, further comprising in that only the valves of the first group, assigned to the rear wheel brakes, can be additionally activated by the second microcontroller.

7. The brake actuation unit as claimed in claim 1 wherein the brake actuation unit further comprises an electrically actuatable diagnostic valve which is arranged in a hydraulic connection between the master brake cylinder pressure space and the pressure medium reservoir vessel, wherein the diagnostic valve can be activated by at least the first microcontroller.

8. The brake actuation unit as claimed in claim 1 further comprising in that an electrically actuatable parking brake actuator on at least one of the wheel brakes which are arranged on the wheel brakes of the rear axle of the motor vehicle can be activated only by the second microcontroller.

9. The brake actuation unit as claimed in claim 1 further comprising in that the wheel brakes are arranged in first and second brake circuits, and in that the second group of valves which can be activated by the first and the second microcontrollers comprises at least one isolating valve for each of the brake circuits for disconnecting the master brake cylinder from the wheel brakes of the first and second brake circuits, and a sequence valve for each of the brake circuits for disconnecting the pressure supply device from the wheel brakes of the brake circuit.

10. The brake actuation unit as claimed in claim 1 further comprising in that the control unit is an open-loop and closed-loop control unit comprises a first and a second electrical connecting element, wherein the open-loop and closed-loop control unit can be supplied with electrical energy from at least a first electrical energy supply device via the first connecting element, and from at least a second electrical energy supply device via the second connecting element.

11. The brake actuation unit as claimed in claim 1 further comprising in that said brake actuation unit has a first pressure sensor, for detecting a pressure of the master brake cylinder, and a second pressure sensor, for detecting a pressure of the pressure supply device, wherein signals of the first pressure sensor are fed only to the first microcontroller, and signals of the second pressure sensor are fed only to the second microcontroller.

12. The brake actuation unit as claimed in claim 1 wherein the brake actuation unit further comprises a redundantly embodied travel sensor or two travel sensors for detecting a position of a brake pedal or of a master brake cylinder piston, wherein at least one signal of the travel sensor or the travel sensors is fed to the first and the second microcontrollers.

13. The brake actuation unit as claimed in claim 1 further comprising in that a first bus connection for a first databus and a second bus connection for a second databus are provided, wherein the first bus connection is connected only to the first microcontroller, and the second bus connection is connected only to the second microcontroller, and in that the first and the second microcontrollers are connected to one another via a third databus.

14. The brake actuation unit as claimed in claim 13, further comprising in that the first bus connection and the second bus connection are arranged on different electrical connecting elements.