WO2019097043A1

WO2019097043A1 - Pressure supply arrangement, braking system, and associated operating method

Info

Publication number: WO2019097043A1
Application number: PCT/EP2018/081687
Authority: WO
Inventors: Robert Grimm; Jochen Zimmermann; Harald Biller
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2017-11-20
Filing date: 2018-11-19
Publication date: 2019-05-23
Also published as: DE102017220686A1

Abstract

Disclosed is a pressure supply arrangement (2) for a braking system of a motor vehicle, comprising a brake master cylinder (6) with a primary chamber (24) and a secondary chamber (40), further comprising a pressure piston (36) which can be moved into a pressurization chamber using an actuator (A) that includes a motor (58) and by means of a rotational-translational gear mechanism, the pressurization chamber being identical to the secondary pressure chamber (40). Also disclosed are a braking system and an associated operating method.

Description

Pressure supply arrangement, brake system and associated operating method

The invention relates to a pressure supply arrangement for a brake system of a motor vehicle, comprising a

Master cylinder with a primary chamber and a seconds därkammer, further comprising one with the aid of an actuator, which comprises a motor and a ver by means of a Rotati ons translation gear in a pressure buildup chamber slidable plunger.

It further relates to a corresponding brake system and an operating method for such a brake system.

For future developments in the field of

By-wire brake systems, especially in the field of highly automated driving (HAF) robust pressure actuator or actuators are required, which can reliably build independent of the driver wheel brake pressure. Likewise, it must be ensured that legally required fallback levels are implemented. These actuators should be particularly suitable for fault tolerant braking systems with fail-silent and fail-operational scenarios.

Pressure delivery devices that can build up pressure independently of the driver are known from the prior art. A disadvantage of known solutions is the required space, which is very scarce in compact vehicles.

Known arrangements for brake-by-wire systems have generally integrated a pedal travel force simulator and are characterized by a large number of components with high system complexity.

The invention is therefore based on the object to provide a pressure provision arrangement that is suitable systems for use in fault tolerant braking in a small space size. Furthermore, a corresponding Braking system and an associated operating method can be specified.

With respect to the pressure supply arrangement, this object is achieved in that the Druckauf building chamber with the secondary pressure chamber is identical.

Advantageous embodiments of the invention are the subject of the dependent claims.

The invention is based on the consideration that Druckguel- lenkomponenten for fault-tolerant brake systems a mechanical African foot pedal operation ("fail-silent") or two electrical rule adjusting drives to realize a

Should have "fail-operational" operation, while at the same time they should require as little construction as possible.

As has now been recognized, these requirements can be met by sharing a chamber of the tandem main cylinder secondary circuit as a pressure chamber for active pressure build-up for space reduction. The secondary piston is rigidly connected to a linear drive and can be moved in both directions.

Advantageously, the pressure piston comprises a first cylinder and a second cylinder.

The second cylinder preferably surrounds the first cylinder at least partially in the radial direction. Preferably, at least one stop for the first and / or second cylinder is provided, which advantageously stops it in its movement in at least one axial direction of movement, while the other cylinder can move in this direction of movement at least for a predetermined path. Preferably, the two cylinders are coupled together via a pawl.

The actuator is coupled in a preferred embodiment with the first cylinder. In a second preferred embodiment, the actuator is coupled to the second cylinder.

The rotation-translation gear preferably comprises one or is formed as a ball screw, wherein the piston is mounted rotationally secured on a spindle of the ball screw, and wherein a nut mounted on the spindle is connected via a belt to the motor shaft, and wherein spindle and motor shaft axially parallel are arranged.

The maximum volume of the secondary chamber is preferably greater than the maximum volume of the primary chamber.

In a preferred embodiment, a second actuator is provided which is adapted to move the primary piston in the primary chamber. If one actuator fails, wheel brake pressure can continue to build up from the other actuator. This pressure supply arrangement is therefore suitable for the "fail-operational" scenario.

With regard to the brake system, the above object is achieved according to the invention with a brake system comprising hydraulically actuable wheel brakes, comprising a brake pedal, comprising a pressure medium reservoir, further comprising a pressure supply arrangement described above.

Advantageously, the secondary chamber is hydraulically connected by a first separating valve separable with two wheel brakes of a first brake circuit and hydraulically connected to two wheel brakes of a second brake circuit.

Preferably, the primary chamber with the wheel brakes of the first brake circuit is separably connected hydraulically by means of a second isolation valve.

With regard to the method, the above-mentioned object is achieved according to the invention by opening the first separating valve in a normal operating mode and the second separating valve is closed.

Advantageously, to generate a desired Pe dalgefühls the pressure in the primary circuit measured by means of a pressure sensor, wherein the pedal travel is measured, and wherein by driving the actuator or actuator and / the control of the second isolation valve, a force feedback is generated on the brake pedal.

Preferably, the secondary chamber is separably connected by means of a Nachsaugventils with the pressure fluid reservoir, wherein each wheel brake is assigned in each case an inlet valve, and wherein in a Nachsaugvorgang the Nachsaugventil is opened and the intake valves are closed.

The advantages of the invention are, in particular, that a pressure supply arrangement in a compact design he is made possible by the use of the THZ secondary chamber for the electric actuator and a small number of valves can be used in elimination of the component "pedal force simulator" in the overall hydraulic circuit diagram in a compact design ,

During normal braking, only two valves are permanently energized. In addition to the basic braking functions, regenerative braking also enables a Biending. The second pressure source for fail-operational operation is integrated into the existing basic architecture, allowing the system to generate a variable path / pressure-dependent area switching.

An embodiment of the invention will be explained in more detail with reference to a drawing. In it show in a highly schematic representation:

FIG. 1 shows a print supply arrangement in a first preferred embodiment;

FIG. FIG. 2 shows a pressure supply arrangement in a second preferred embodiment; FIG. F IG. 3 shows a brake system with a pressure supply arrangement according to FIG. 2; and

F IG. 4 shows a pressure supply arrangement in a third preferred embodiment.

Identical parts are provided with the same reference numerals in all figures.

An in FIG. 1 illustrated Druckbereit position arrangement 2 is formed substantially in the manner of a tandem master cylinder 6, which comprises an actuatable by means of an actuatable brake pedal 10 via a coupling rod 14 primary piston 20 which is moved upon actuation of the brake pedal 10 in a Pri märkammer 24. The primary piston 20 is acted upon by an arranged in the primary chamber 24 elastic element 28, whereby the primary piston 20 is moved in the unactuated state of the brake pedal 10 in its unactuated position. The piston travel of the primary piston 20 is measured by means of a, preferably redundant, displacement sensor 32 ge. A secondary piston 36 is in a secondary chamber 40 and is acted upon by an in the secondary chamber 40 arranged elastic element 42. The elastic elements 28, 42 are preferably each formed as a spring.

The secondary piston 36 includes an outer cylinder 52 and a radially disposed therein inner cylinder 50. A motor shaft or drive shaft 62 of an electric motor 58 is coupled via a belt 66 with a nut 70 of a ball screw GE. Motor, belt 66 and ball screw form a first drive or actuator A. The secondary piston 36 thus acts as a pressure piston in an active pressure build-up with the aid of the actuator A.

The inner cylinder 50 is rotatably supported on the spindle 74 of the ball screw. The inner cylinder 50 is also prevented by means of a rotation lock on its rotation ver, so that it rotates the spindle 74 in two opposite directions performs axial movements or Transla tions. The angle of rotation of the motor shaft 62 is detected by means of a preferably redundant rotational angle sensor 78, from which then a corresponding piston travel of the piston or cylinder 50, 52 is calculated.

In the starting position without pedal operation, the primary chamber 24 is connected via a Schnüffelloch 84 with a hydraulic line 88, which is connectable to a pressure medium reservoir or reservoir of a brake system. The secondary chamber 40 uses a central valve connection of the inner or inner cylinder 50 to the reservoir or the reservoir for pressure equalization.

A conventional dual-circuit brake system with the pressure supply arrangement in the fallback level is maintained. The primary chamber 24 preferably feeds a primary circuit I and the secondary chamber 40 preferably feeds the secondary circuit II.

The driver's request is via the Pedalstangenweg 32 and a pressure sensor 242, see FIG. 3. recorded. Pressure sensors (not shown) determine the pressure in the primary 24 and secondary chamber 40.

The illustrated pressure-providing arrangement 2 is suitable for operation in a "fail-silent" mode in a braking system This fall-back mode comes into effect when the electrical supply / control of the ready-to-print position arrangement 2 fails Actuation of the brake pedal 10 build up pressure in the primary and secondary circuit, this is achieved in particular by the fact that the pressure supply arrangement 2 in fail-silent mode can function as a master brake cylinder which allows the driver to build up brake pressure by means of muscular force. The secondary chamber 40 fulfills a dual function: on the one hand, it is a pressure chamber of a device for active pressure build-up with the aid of the motor and at the same time a secondary chamber of an actuatable by means of the brake pedal 10 tandem master cylinder. 6

A simultaneous movement of inner cylinder 50 and outer cylinder 52 is preferably carried out when as much volume of brake fluid is to be moved. A displacement of only the inner cylinder 52 is preferably performed by when a high pressure is to be generated. Preferably, the two cylinders 50, 52 are coupled together during normal braking. At high pressure requirements, z. B. in AEB operation, a further longitudinal movement of the outer piston is limited by a wegab dependent attack and a latching device. The inner piston is moved further and generates a higher pressure level due to this surface switching.

In FIG. 2, a pressure supply arrangement 2 is shown in a further preferred embodiment. In contrast to the in FIG. 1, the pressure supply arrangement 2 shown in FIG. 2 illustrated Druckbereitstellungsanordnung 2 without being actuated by a driver brake pedal. It is therefore particularly suitable for highly automated driving without mechanical-hydraulic fallback, in which the driver brakes by muscle power, suitable.

The pressure supply arrangement 2 has for this purpose a further electric motor 100. A motor shaft or drive shaft 104 of the further electric motor 100 is coupled via a belt 108 with a nut 110 of a further ball screw drive. The piston 20 is rotatably supported on the spindle 106 of the ball screw. The piston 20 is also prevented by means of a rotation assurance on its rotation, so that it performs axial movements or translations in rotations of the spindle 106 in two opposite directions. The rotation angle of the motor shaft 104 is detected by means of a preferably redundantly formed rotation angle sensor 112.

This variant of the pressure supply arrangement is in particular special suitable for a fail-operational mode. At a Failure of one of the two electric motors 58, 100 can still move the other electric motor, the corresponding piston 20, 36 in the respective pressure chamber 24, 40 to build up wheel brake pressure. Both engines are supplied from a separate and re dundanten board network and are galvanically separated from each other.

A braking system 140 of the type shown in FIG. 2 illustrated Druckbe provision arrangement is shown in FIG. 3 shown. It has four hydraulically actuated wheel brakes 150, 152, 154, 156, to each of which a normally open inlet valve 160-166 and a normally closed exhaust valve 170-176 is hydraulically arranged. Between the respective outlet valve 170-176 and the respective wheel brake 150-156, a filter is preferably arranged in each case. In the inlet valves 160-166, a filter is preferably arranged upstream of the inlet and outlet ports. Preferably, a check valve is hydraulically connected in parallel to the respective inlet valve 160-166. The return check valves are not shown in the drawing.

The primary chamber 24 is connected by a hydraulic compensation line 180 with a pressure medium reservoir 184. Via a hydraulic brake pressure supply line 188, the primary chamber 24 is connected to the input terminals of the input valves 160, 162. The primary chamber 24 and the input valves 160, 162 associated wheel brakes 150, 152 are part of a first brake circuit I and a primary circuit. The connection between the primary chamber and the wheel brakes 150, 152 is, if necessary, separable by means of a separating valve 190.

The secondary chamber 40 is connected via a hydraulic brake pressure supply line 204 to the input terminals of the A input valves 164, 166, so that they can supply the wheel brakes 154, 156 of a second brake circuit II or secondary circuit with wheel brake. Preferably, no separating valve is arranged in this particular connection. The secondary chamber 40 is connected by a hydraulic Bremsver sorgungsleitung 194 with the wheel brakes 150, 152 of the first brake circuit I, said compound is releasable or separable by a line 194 arranged, preferably normally closed Druckzuschaltventil 200. A hydraulic compensating line 220 connects the hydraulic line 194 with the pressure fluid reservoir 184, this connection being separable by a preferably normally closed separating valve 218.

During normal braking in "by-wire" operation, the valve 190 is energized closed and the valve 200 is energized open.Thus, in systems without regenerative braking, the number of energized valves remains reduced to two.The wheel brakes 150-156 are from the driven stepped piston Depending on the travel path, the stepped piston 36 permits a surface switchover - from a volume control (cylinder surface of the inner piston or cylinder 50 and the outer piston or cylinder 52) to a pressure control (cylinder end surface of the inner piston or piston). Cylinder 50). The system pressure is measured with a pressure sensor 240.

In the "fail-silent" mode, pressure generator arrangement according to the embodiment in FIG. 1, the entire braking energy comes from the driver Due to the dual-circuit nature, the primary circuit I supplies two wheel brakes 150, 152, whereas the remaining wheel brakes 154, 156 To supply all the wheel brakes 150-156 with an approximately equal pressure level, the cylinder end face of the inner piston or cylinder 50 is used in the hydraulic fallback level, so that when idle, the piston or cylinder 52 in its rest position The driver braking force is transmitted to the cylinder 1 via the bound DK piston.

To generate the pedal feel (embodiment FIG. 1), preferably no hydraulic or electrical simulator (passive Component) is used. The pedal feel is advantageously created with the pressure in the primary chamber 24. A pressure sensor 242 in the primary circuit I allows the exact monitoring / compliance with the required force-displacement curve. The pedal travel is determined via the sensor 32.

By the method of secondary piston 36 by controlling the motor 58 and / or the metered opening of the analog valve 190, the force feedback is generated on the driver pedal 10.

During autopilot braking system pressure in the secondary chamber 40 is generated according to the Nor malbremsfunktionalität. In case of failure with electrical failure of motor 58 or drive A accepts drive B and generates the pressure build-up in the primary chamber 24, a pressure in the secondary chamber 40. Alternatively, in this structure, the drive B can be replaced by a radial piston pump and pressure supply via the Primärkreisschnüffelloch a coupling to the secondary circuit II is achieved.

Alternatively, according to FIG. 4, the drive A are also tied to the outer cylinder 52. In FIG. FIG. 4 shows another preferred embodiment of a pressure supply arrangement 2. This differs from that shown in FIG. 2 variant shown that by the drive A of the outer cylinder 52 and not the inner cylinder 50 is driven by secondary piston 36.

For switching surfaces in the high-pressure operation of the secondary chamber 40, the cylinder 52 can be held at rest with variable displacement and / or pressure according to a method of drive or actuator A, and the cylinder 50 is triggered by operation of drive B in a force / pressure-dependent manner and moved on.

During an ABS operation, according to the open architecture of the brake system 140, hydraulic fluid is delivered via the outlet valves 170-176 into the reservoir or the pressure fluid reservoir 184. By the corresponding lumenverbrauch the driven secondary piston 36 moves toward the right stop. To avoid a sagging pedal 10 is due to the larger seconds därvolumens via the valve 190, a volume flow in the Pri märkammer 24 promoted to Pedalpositionsaufrechterhaltung.

A targeted secondary piston movement gives the driver a haptic pedal feedback. In order to recirculate the "lost hydraulic volume" in a refill cycle, the four intake valves 160-166 are closed and the valve 218 is opened, the secondary piston 36 is driven toward zero position from the primary circuit I fluid volume via the valve 190 into the secondary chamber 40 promoted.

During regenerative braking, the mechanical friction brakes are also added. In the case of a volume veneer, either the secondary piston 36 is moved to the right in accordance with the pedal feel, and secondary circuit volume is discharged through valve 218 into the pressure medium reservoir 184 or the volume is maintained at the corresponding pressure gradient across the valve 190 by moving the actuator with closed inlet valves 160-166 On the left, volumes from the primary chamber 24 are "redistributed" into the larger secondary chamber 40 via the opened valve 190. For self-diagnostic purposes, additional diagnosis valves are also conceivable.

Claims

claims

A pressure supply arrangement (2) for a brake system of a motor vehicle, comprising a master cylinder (6) having a primary chamber (24) and a secondary chamber (40), further comprising one by means of an actuator (A) comprising a motor (58) and a pressure piston (36) which can be displaced into a pressure build-up chamber by means of a rotation-translation gear,

characterized in that

the pressure buildup chamber is identical to the secondary pressure chamber (40).

2. Pressure-providing arrangement (2) according to claim 1, wherein the pressure piston comprises a first cylinder (50) and a second cylinder (52).

3. pressure supply arrangement (2) according to claim 2, wherein the second cylinder (52) surrounds the first cylinder (50) at least partially in the radial direction.

4. pressure supply arrangement (2) according to claim 2 or 3, wherein in at least one axial direction of movement, a stop for the first and / or the second cylinder is provided.

5. Pressure-providing arrangement (2) according to one of claims 2 to 4, wherein the actuator (A) is coupled to the first cylinder (50).

The pressurized supply assembly (2) according to any one of claims 2 to 4, wherein the actuator (A) is coupled to the second cylinder (52).

7. pressure supply arrangement (2) according to one of the claims 1 to 6, wherein the rotation-translation gear comprises a ball screw, wherein the pressure piston is rotatably mounted and rotationally secured on a spindle (74) of the Kugelge wind, and wherein on the spindle (74) mounted nut (70) via a belt (66 ) is connected to a motor shaft (62) of the motor (58), and wherein spindle (74) and motor shaft (62) are arranged axially parallel.

8. pressure supply arrangement (2) according to one of the preceding claims, wherein the maximum volume of the secondary chamber (40) is greater than the maximum volume of the primary chamber (24).

9. pressure supply arrangement (2) according to any one of the preceding claims, wherein a second actuator (B) is provided, which is adapted to move a primary piston (20) in the primary chamber (24).

10. A braking system (140) for motor vehicles, comprising hydraulically actuated wheel brakes (150-156), comprising a brake pedal (10) comprising a pressure fluid reservoir (184), further comprising a pressure supply arrangement (2) according to one of the preceding claims.

11. The brake system (140) according to claim 10, wherein the secondary chamber (40) by a first isolation valve (200) separable with two wheel brakes (150, 152) of a first brake circuit (I) hydraulically connected hydraulically and hydraulically with two wheel brakes (154, 156) of a second brake circuit (II) is connected.

12. Brake system (140) according to claim 11, wherein the primary chamber (24) with the wheel brakes (150, 152) of the first brake circuit (I) separable by means of a second isolation valve (190). hydraulically connected.

13. A method for operating a brake system (140) according to

Claim 12, wherein in a normal mode, the first isolation valve (200) is opened and the second isolation valve

(190) is closed.

14. The method of claim 13, wherein for generating a desired pedal feel, the pressure in the first brake circuit (I) by means of a pressure sensor (242) is measured, and wherein the pedal travel is measured, and wherein by driving the actuator (A) and / Triggering of the second isolation valve (190) a force feedback to the brake pedal (10) is generated.

15. The method of claim 13 or 14, wherein the secondary chamber (40) separable by means of a Nachsaugventils (218) to the pressure fluid reservoir (184) is connected, and wherein each wheel brake (150-156) each associated with an inlet valve (160-166) is, and wherein in a Nachsaugvorgang the Nachsaugventil (218) is opened and the inlet valves (160-166) are closed.