JPH079975A - Hydraulic type two circuit brake device - Google Patents

Abstract

PURPOSE: To avoid complete failure in a brake device based on the suction of air due to an error in a two-circuit brake device. CONSTITUTION: An auxiliary hydrounit 43 has a plunger 48 and a pressure piston 51, slidable in an axial direction aganist a return spring 52 in a work cylinder 50, restricts control and pressure chambers 53 and 54, to make the chamber 54 be connected to a plunger inlet 57 via a center valve incorporated into the piston 51, moreover be directly connected to a plunger outlet 58. The pluner 48 is arranged in a connection conduit assigned to an outlet passage 23 for a driving wheel 2 from another brake circuit outlet 16, and moreover the inlet 57 is connected to the outlet 16, to connect the outlet 58 to a control valve, thereby connecting the control chamber of the plunger 48 to the inlet of a pressure limit valve 47.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic two-circuit braking device having a diagonally divided braking circuit having a skid control system (ABS) and a traction control system (ASR). A master brake cylinder having two separate brake circuit outlets for controlling the output of brake pressure during operation, a brake fluid container connected to the master brake cylinders, and a four-passage hydro connected to both the brake circuit outlets. And a four-passage hydro unit is provided for each brake circuit.
Four outlet passages divided into two brake circuits for connecting the wheel brake cylinders of one driven vehicle wheel and an undriven vehicle wheel, each one of which
An electromagnetic control valve associated with one outlet passage for controlling the output of the brake pressure associated with the wheel slip, said control valve being connected on the one hand to said one outlet passage, respectively. , On the other hand, is connected to a master brake cylinder via a connecting conduit, and said four-passage hydro unit has a return feed pump,
The return feed pump comprises two separate pump elements acting in each one brake circuit for returning the brake fluid when the brake pressure is reduced, each pump element on the inlet side via the control valve. hand,
Connectable to an outlet passage belonging to one of the brake circuits, on the outlet side, connected to a master brake cylinder connection connected to a connecting conduit of the control valve associated with the outlet passage for the drive wheel, Further, the four-passage hydro unit is assigned to each one brake circuit for temporarily containing the brake fluid when the brake pressure is reduced.
Has two low-pressure accumulators, each low-pressure accumulator is connected to the inlet of each pump element, and an auxiliary hydro unit for supplying brake pressure during traction control operation is provided. A hydro unit has a suction conduit leading from the brake fluid container to an inlet of a pump element of the return feed pump, and a charge valve arranged in the suction conduit, the charge valve at least including the suction conduit. It is opened at the time of traction control and is shut off at the time of operating the brake pedal. Further, the auxiliary hydro unit has a switching valve, and the switching valve drives one of the brake circuit outlets of the master brake cylinder and the drive. Master of control valve assigned to the outlet passage for the wheel A pump element of the return feed pump, which is connected to the suction conduit, is connected to a control valve, which is arranged in a connecting conduit between the rake cylinder connection and is arranged in the outlet passage for the drive wheel. Of a type in which the control valve shuts off the connection conduit during traction control operation and connects the master brake cylinder connection part of the control valve to the brake fluid container via a pressure limiting valve. Regarding

[0002]

2. Description of the Prior Art In a known two-circuit braking device of this type having a diagonally divided braking circuit (DE 3816073), for each braking circuit, a charge valve and a A complete valve system consisting of a switching valve and a pressure limiting valve is provided, each of which is a 2-port 2 with charge valve hydraulically controlled.
As the position valve, the switching valve is configured as a 3-port 2-position solenoid valve.

In such a known two-circuit braking device, ASR operation is performed when there is an error such that the connecting conduit between the auxiliary hydro unit and the brake fluid container is pulled out from the auxiliary hydro unit. At times, there is a risk that air will be sucked in and both brake circuits will fail. That is, the vehicle is no longer braked due to a complete failure of the brake device.
Such a negligent case is temporarily placed at a high position for the purpose of preventing the brake fluid container from flowing out when the connecting conduit leading to the brake fluid container is pulled out from the auxiliary hydro unit during maintenance work of the auxiliary hydro unit, for example. Can be permanently installed and then forgetting to properly connect the connecting conduit to the auxiliary hydro unit again after the maintenance work is completed.

In order to avoid such a negligence case,
A second brake fluid container equipped with a level switch is arranged between the brake fluid container and the auxiliary hydro unit,
It has already been proposed to make the connecting conduit between the auxiliary hydro unit and the second brake fluid container non-decomposable. In this case, it is only necessary to separate the connecting conduit between the two brake vessels during maintenance work. If it is forgotten to remake the connection between the two brake fluid containers after maintenance is complete, the return feed pump draws in brake fluid from the second brake vessel during ASR operation, which means that It is performed until the liquid level in the liquid container falls below the specified value and the level switch returns and shuts off the feed pump. This will certainly abandon the brake system's ASR and ABS functions, but the brake system itself is still fully functional so that the vehicle can safely search for the next repair shop.

However, such an additional brake fluid container with a level switch would otherwise require an additional mounting space in the vehicle in addition to the already large volume hydro unit.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to improve a two-circuit braking device of the type mentioned at the outset to avoid the disadvantages mentioned above and to avoid complete failure of the braking device, which results in It is to provide a two-circuit braking device that ensures safety.

[0007]

In order to solve this problem, in the structure of the present invention, the auxiliary hydro unit has a plunger having a central valve, and
A pressure piston, which is slidable in the axial direction against the return spring in the working cylinder, limits the control chamber on the one hand and the pressure chamber on the other hand, which pressure chamber is incorporated in the pressure piston. It is connected to the plunger inlet through the central valve that is closed when the piston slides, and the pressure chamber is directly connected to the plunger outlet, and the plunger is connected from the other brake circuit outlet of the master brake cylinder to the other. A plunger conduit arranged in a connecting conduit leading to the control valve associated with an outlet passage for a drive wheel provided in the brake circuit, the plunger inlet being connected to the other brake circuit outlet, The outlet is connected to the control valve, and the control chamber of the plunger is connected to the inlet of the pressure limiting valve.

[0008]

The two-circuit braking device according to the present invention includes:
It has the following advantages over conventional ones. That is,
Even without the provision of a second brake fluid container with a level switch in the negligent case, a complete failure of the braking device is prevented and the vehicle remains braking even if limited. Air intake in the brake circuit, which is accidentally separated from the brake fluid container, can lead to failure of this brake circuit in this case too, but said air intake is limited to this brake circuit only. The other brake circuit, which is controlled during ASR operation by the plunger provided in the two-circuit brake circuit according to the invention, remains blocked against inhaled air and thus maintains its functionality when operating the brake pedal. There is. Due to the reduced braking power, the driver is aware of the fault and can search for a repair shop without risk.

At the expense of additional costs due to the additional plunger provided in the second brake circuit, the complete valve arrangement of charge valve, switching valve and pressure limiting valve for this brake circuit is saved. Therefore, the cost and the required construction space are offset each other. A second no longer needed brake fluid container with a level switch is also saved, which is clearly recognized both in terms of price and the required mounting space provided on the vehicle.

On the basis of the measures described in claims 2 and below, an advantageous improvement of the hydraulic two-circuit braking device according to claim 1 becomes possible.

In an advantageous configuration of the invention, a hydraulically controlled two-port two-position valve is connected in parallel to the pressure limiting valve, the control inlet of the two-port two-position valve being the master brake cylinder. Connected to the brake circuit outlet, the two-port two-position valve is configured to close in an uncontrolled basic position and open in an actuated position. During braking during ASR operation, the ABS function of the braking device can be activated very quickly, since the 2-port 2-position valve allows a rapid pressure relief of the plunger bypassing the pressure limiting valve.

The pump element of the return feed pump connected to a suction conduit leading to a brake fluid container comprises:
Generally, it is configured to be self-sucking. In another configuration of the invention, a pre-charge pump is connected to the suction conduit when it is made very long. If the suction conduit is short, the use of a pre-charge pump eliminates the need for the pump element to be self-suctioning. The reason is that the previous charge pump
This is because the brake fluid is supplied to the pump element from the brake fluid container at a constant charge pressure. In the case of ASR, the front charge pump together with the return feed pump closes the circuit.

In a further advantageous configuration of the invention, the four-passage hydro unit has four inlet passages, of which two inlet passages are for drive wheels in each brake circuit. Forming the master brake cylinder connection of the control valve assigned to the outlet passage of
One inlet passage forms the master brake cylinder connection of the control valve associated with the outlet passage for the vehicle wheel that is not driven in each brake circuit. Each inlet passage is connected to the master brake cylinder via a separate connecting conduit, the inlet passages belonging to a common brake circuit being connected to the same brake circuit outlet of the master brake cylinder. With such a configuration of the four-passage hydro unit, it is possible to eliminate the control of the control valve assigned to the vehicle wheel that is not driven during ASR operation.

In order to save the connecting conduit between the master brake cylinder and the four-passage hydro unit, in a further development of the invention, the four-passage hydro unit has only two inlet passages. , The inlet passage forms the master brake cylinder connection for each two control valves located in each brake circuit. Each inlet passage is connected via a connecting conduit to the brake circuit outlet of the corresponding master brake cylinder. In this case, during ASR operation, the control valve assigned to the wheel brake cylinder of the vehicle wheel that is not driven is switched to the shutoff position,
This interrupts the braking pressure reduction in the wheel brake cylinders of the vehicle wheel that is not driven.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

2 for a passenger vehicle with a diagonally divided braking circuit, which is shown in a block circuit diagram in FIG. 1 and which comprises a skid control system (ABS) and a traction control system (ASR), also called a front drive control system. In the circuit brake device, the wheel brake cylinder 10 of the drive wheels 11 and 12 is used.
Is divided into two brake circuits together with the wheel brake cylinders 10 of the non-driven wheels 13, 14, so that one wheel brake cylinder 10 for each drive wheel 11 or 12 and one for each non-driven wheel 13 or 14 are provided. The wheel brake cylinders 10 and 10 belong to one brake circuit. In general,
The drive wheels 11, 12 are the front wheels of a passenger car. 2 above
A master brake cylinder 15 belongs to the circuit brake system in a known manner, which master brake cylinder 15 has two separate brake circuits for connecting each one of the two brake circuits.
It has one brake circuit outlet 16, 17 and is connected to a brake fluid container 18. When the brake pedal 19 is operated, an equal amount of brake pressure is output-controlled at both brake circuit outlets 16 and 17.

A four-passage hydro unit 20 further belongs to the two-circuit braking device, and the four-passage hydro unit has four outlet passages 21, 22, 2.
3, 24 and four inlet passages 25, 26, 27, 28. The two inlet passages 25, 26 belonging to one of the braking circuits are respectively separate connecting conduits 29a, 29.
The two inlet passages 27, 28 connected to the brake circuit outlet 17 of the master brake cylinder 15 via b and belonging to the other brake circuit have separate connecting conduits 30a,
It is connected to the brake circuit outlet 16 of the master brake cylinder 15 via 30b. The wheel brake cylinders 10 of the wheels 11, 12, 13, and 14 are connected to the outlet passages 21, 22, 23, and 24 of the four-passage hydro unit 20, respectively. Each exit passage 21,22
Control valves 31, 32, 33, 34 are assigned to 23, 24. The control valves 31, 32, 33, 34 are controlled by an electronic control unit (not shown) to create a wheel slip-related brake pressure in the corresponding wheel brake cylinder 10. The return feed pump 35, which is a component of the four-passage hydro unit 20, has two
There are two pump elements 36, 37, which are driven together by an electric motor 38 and serve to carry back the brake fluid during pressure reduction in the brake. Each pump element 36 or 37 is designed to operate in a brake circuit and is connected on the inlet side to a control valve 31, 32 or 33, 34 belonging to that brake circuit. In addition, the pump elements 36, 37 are each connected on the inlet side to a low-pressure accumulator 40. The low-pressure accumulator 40 works to temporarily store the brake fluid flowing out from the wheel brake cylinder 10. Both pump elements 36, 37 are connected on the outlet side to the inlet passage 26 or the inlet passage 27 of the four-passage hydro unit 20. That is, the two pump elements are connected to the outlet passages 22 and 23 connected to the wheel brake cylinders 10 of the drive wheels 11 and 12 via the control valves 32 and 33, respectively.
That is, it is connected to 6, 27. The buffer chamber 41 and the throttle portion 42 can be connected to the respective connection paths between the pump elements 36 and 37 and the inlet paths 26 and 27. Each pump element 36, 37 has a pump inlet valve 60 and a pump outlet valve 61. The pump element 36 is configured to be self-sucking.

The control valves 31, 32, 33, 34 are designed as 3-port 3-position solenoid valves having a spring return position, in which case the first valve position, that is to say the unexcited basic valve position, is the inlet. A smooth flow is formed from the passages 25, 26, 27, 28 to the corresponding outlet valves 21, 22, 23, 24, so that the wheels 11, 12, 13, 14 are provided.
A predetermined brake pressure can be generated in the wheel brake cylinder 10 of the above. In the second valve position, i.e. the valve intermediate position, which can be produced by excitation with a half maximum current, the flow is cut off and all outlet valves 2
Since 1, 22, 23 and 24 are cut off, the brake pressure formed in the wheel brake cylinder 10 is retained. In the third valve position, i.e. in the valve position which can be produced by excitation at maximum current, the outlet valves 21, 22 or 23, 24 are connected to the pump element 36.
Alternatively, since it is connected to the inlet of 37, the brake fluid can be taken out from the wheel brake cylinder 10 again for the purpose of reducing the brake pressure. In the connection between the control valves 31, 32 and the inlet of the pump element 36, a check valve 39 having a flow direction facing the pump element 36 is provided.
Are arranged.

The auxiliary hydro unit 43 works to supply the brake pressure during the traction control operation (ASR operation). The auxiliary hydro unit includes a suction conduit 44 communicating with an inlet of a pump element 36 of the return feed pump 35 configured to be self-sucking from the brake fluid container 18, and a charge valve 45 arranged in the suction conduit 44. Connection conduit 2 leading from the brake circuit outlet 17 of the master brake cylinder 15 to the inlet passage 26
It has a switching valve 46 arranged at 9b, a pressure limiting valve 47 and a plunger 48 with a central valve 49. The charge valve 45 is designed as a hydraulically controlled two-port two-position valve with a spring return position which opens the suction conduit 44 in its uncontrolled basic position. , Shut off at the switching controlled operating position. For this purpose, the control inlet of the charge valve 45 is connected to the brake circuit outlet 17 of the master brake cylinder 15. The switching valve 46 is configured as a 3-port 2-position solenoid valve having a spring return position. Of the three valve connections, the first valve connection is connected to the inlet passage 26 of the four-passage hydro unit 20, and the second valve connection is connected to the brake circuit outlet 17 of the master brake cylinder 15. The third valve connection is connected to the inlet of the pressure limiting valve 47, the outlet of which is connected to the suction conduit 44 or the brake fluid container 18. The switching valve 46, which in this case is embodied as a three-port two-position solenoid valve, has its first valve connection connected to the second valve connection in its unexcited valve basic position and is generated by excitation. It is arranged to be connected to the third valve connection in the valve switching position provided. The switching valve 46 is constantly switched during the ASR operation, whereby the master brake cylinder 15 is separated from the inlet passage 26 of the four-passage hydro unit 20, and this inlet passage is connected to the inlet of the pressure limiting valve 47.

The plunger 48 has a working cylinder 50 in which the pressure piston 51 is
It is guided so as to be slidable in the axial direction against the spring force of the return spring 52. The pressure piston 51, together with the working cylinder 50, limits the control chamber 53 on the one hand and the pressure chamber 54 on the other hand. The return spring 52 is fitted in the pressure chamber 54 and is supported on the one hand by the pressure piston 51 and on the other hand by the cover 55 closing the working cylinder 50 at one end. The control chamber 53 is connected via a control conduit 56 to the third valve connection of the pressure limiting valve 47 or the switching valve 46. The plunger 48 has a plunger inlet 57 and a plunger outlet 58, and is connected from the brake circuit outlet 16 of the master brake cylinder 15 to the 4-passage hydro unit 2.
It is connected to the connecting conduit 30b leading to the 0 inlet passage 27. In this case, the plunger inlet 57 is located on the side of the brake circuit outlet 16 and the plunger outlet 58 is located on the side of the inlet passage 27. The plunger outlet 58 opens directly into the pressure chamber 54, while the plunger inlet 57 is connected to the pressure chamber 54 via a central valve 49. The central valve 49 is always open at the basic position of the pressure piston 51, and forms a connection path between the plunger inlet 57 and the plunger outlet 58 through the pressure chamber 54. After moving from the position, the central valve closes and the plunger inlet 57
And the plunger outlet 58 are configured to be blocked from each other. In the closed state of the central valve 49, the pressure piston 51 corresponds to the pressure input to the control chamber 53,
The spring force of the return spring 52 is shifted to the right as viewed in FIG. 1, whereby the brake pressure is output-controlled at the plunger outlet 58.

At least one of the drive wheels 11, 12 indicates a wheel slip, and when this is notified to an electronic control unit (not shown) via a wheel slip sensor (not shown), the electronic control unit is activated. The directional control valve 46 is switched by and the circuit of the return feed pump 35 is closed. The self-suction pump element 36 sucks the brake fluid from the brake fluid container 18 by means of the opened charge valve 45, and this brake fluid is transferred via the switched switching valve 46 to the pressure limiting valve 4
7 or return to the brake fluid container 18 as the case may be. The pressure on the outlet side of the pump element 36 is
This corresponds to the pressure adjusted by the pressure limiting valve 47, which is usually 70 bar. The pressure at the outlet of the pump element 36 or the pressure at the inlet of the pressure limiting valve 47 is guided to the control chamber 53 of the plunger 48 via the control conduit 56. This pressure moves the pressure piston 51, so that in this case the central valve 49 is first closed, disconnecting the master brake cylinder 15 from the other brake circuit. Due to the movement of the pressure piston 51, a pressure is generated in the inlet passage 27 of the four-passage hydro unit 20 which is approximately equal to the pressure on the outlet side of the pump element 36 in another brake circuit. The difference between these two pressures corresponds to the friction plus the return force of the return spring 52 that occurs when the pressure piston 51 slides. Thus, ASR
During operation, brake pressure is supplied to both brake circuits. Depending on which of the two drive wheels 11, 12 is exhibiting wheel slip,
Brake pressure is built up in the associated wheel brake cylinder 10 by appropriate control of the corresponding control valve 32 or 33 or both control valves. Control valve 32 or 3 assigned to drive wheel 11 or 12 that is not slipping
3 is in this case switched to the intermediate position. In this intermediate position, the corresponding wheel brake cylinder 10 is shut off, so that no brake pressure can be built up at this location. At the end of the ASR cycle, that is, when the slipping drive wheel 11 or 12 is braked until the wheel slip is eliminated, the respective control valve 32 or 33 is shifted to the valve end position. In this valve end position, the wheel brake cylinder 10 is connected to the pump element 36 or 37.

At the end of the ASR operation, the brake pressure of the wheel brake cylinder 10 is reduced, and the brake fluid volume is returned to the brake fluid container 18 and conveyed. The pressure piston 51 provided on the plunger 48 is returned to its basic position by the pump element 37 and the return spring 52, which also reduces the pressure in the inlet passage 27 and the brake circuit of the drive wheel 12. After that, the control of the switching valve 46 is released, and the switching valve returns to the basic position.

As shown by the broken line in FIG. 1, the pressure limiting valve 4
A hydraulically controllable two-port two-position valve 59 having a spring return position may be connected in parallel with 7. The control inlet of the 2-port 2-position valve 59 is connected to the brake circuit outlet 17 of the master brake cylinder 15. In the uncontrolled basic position, the 2-port 2-position valve 59 is closed, whereas in the switching-controlled actuated position it closes the pressure limiting valve 47. This 2-port 2-position valve 59 is used for the brake pedal 19 during ASR operation.
When it is braked through the control chamber 53, it allows a quick discharge. Due to the short circuit of the pressure control valve 47, the control chamber 53 can be emptied very quickly, so that the skid control system (ABS) is ready for functioning very quickly.

A front charge pump 62 may also be connected to the suction conduit 44, as also shown in dashed lines in FIG. This pre-charge pump is connected to and disconnected from the circuit together with the return feed pump 35 during ASR operation. In this case, the front charge pump 62 is located between the brake fluid container 18 and the connection point in the suction conduit 44 of the pressure limiting valve 47 connected to the switching valve 46. Another pressure limiting valve 63 is connected in parallel to the front charge pump 62, and this pressure limiting valve limits the outlet pressure of the front charge pump 62. Such a front charge pump 62 is used when the suction conduit 44 between the four-passage hydro unit 20 and the brake fluid container 18 is formed to be extremely long, or when the return feed pump 3 is used.
This is advantageous when the pump element 36 of No. 5 is not configured to be self-suctioning.

In the two-circuit braking device shown in the block circuit diagram of FIG. 2, a four-passage hydro unit 20 'is used.
Has only two inlet passages 26, 27. Inside the four-passage hydro unit 20 ', as shown in FIG.
In the circuit brake device, the control valves 31, 34, which were connected to the inlet passages 25, 28 which do not exist in this case, are connected to the inlet passages 26, 27. Based on this variant, the connecting conduits 29a, 30a shown in FIG. 1 are saved and two connecting conduits 29, passing through the auxiliary hydro unit 43 between the four-passage hydro unit 20 'and the master brake cylinder 15 are provided. There are only 30. However, during ASR operation, the wheel 1 not driven
It is necessary to switch the control valves 31, 34 of 3, 14 to the valve intermediate position so as to shut off the wheel brake cylinder 10 of the wheels 13, 14 so that no brake pressure is applied to this wheel brake cylinder. Become.

Since the two-circuit braking device shown in FIG. 2 corresponds to the two-circuit braking device shown in FIG. 1 in terms of structure and function type, the same components are designated by the same reference numerals.

The present invention is not limited to the above embodiment. That is, each of the control valves 31, 32, 33, 34 may be configured as one valve unit including an inlet valve and an outlet valve. The inlet valve and the outlet valve are each configured as a 2-port 2-position solenoid valve having a spring return position. In this case, the inlet valve is the inlet passage 25,
26, 27, 28 and the outlet passages 21, 22, 23, 24, whereas the outlet valves are the outlet passages 21, 22 or 23, 24 and the pump element 3.
It is located between 6 and 37 entrances.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a two-circuit brake device showing a first embodiment of the present invention.

FIG. 2 is a block circuit diagram of a two-circuit brake device showing a second embodiment of the present invention.

[Explanation of Codes] 10 Wheel Brake Cylinder, 11, 12 Drive Wheel, 13, 14 Wheel, 15 Master Brake Cylinder, 16, 17 Brake Circuit Exit,
18 brake fluid container, 19 brake pedal, 2
0,20 '4-passage hydro unit, 21,2
2,23,24 outlet passage, 25,26,27,28
Entrance passage, 29, 29a, 29b, 30, 30a,
30b connection conduit, 31, 32, 33, 34 control valve, 35 return feed pump, 36, 37 pump element, 38 electric motor, 39 check valve,
40 low-pressure accumulator, 41 buffer chamber, 42 throttle part, 43 auxiliary hydro unit, 44 suction conduit, 45 charge valve, 46 switching valve, 47
Pressure limiting valve, 48 plunger, 49 central valve,
50 working cylinder, 51 pressure piston, 52
Return spring, 53 Control chamber, 54 Pressure chamber, 55
Cover, 56 control conduit, 57 plunger inlet,
58 Plunger outlet, 59 2-port 2-position valve,
60 pump inlet valve, 61 pump outlet valve, 62
Front charge pump, 63 pressure limiting valve

Claims (9)

[Claims] 1. A skid control system (AB
S) and a traction control system (ASR), which is a hydraulic two-circuit brake device having a diagonally divided brake circuit, and two separate brakes for controlling the output of the brake pressure when the brake pedal is operated. A master brake cylinder having a circuit outlet, a brake fluid container connected to the master brake cylinder, and a four-passage hydro unit connected to the two brake circuit outlets are provided. , Four outlet passages divided into two brake circuits for connecting wheel brake cylinders, one for each driven and non-driven vehicle wheel per brake circuit, and one for each one outlet passage To control the output of brake pressure associated with wheel slips assigned Has a solenoid type control valve,
The control valves are connected on the one hand to each one of the outlet passages and on the other hand to a master brake cylinder via a connecting conduit, and the four-passage hydro unit has a return feed pump. The return feed pump comprises two separate pump elements acting in each one brake circuit for returning the brake fluid when the brake pressure is reduced, each pump element at the inlet side comprising the control valve. Via the outlet passage belonging to one of the brake circuits, and on the outlet side it is connected to the master brake cylinder connection connected to the connection conduit of the control valve assigned to the outlet passage for the drive wheel. In addition, the four-passage hydro unit has one brake for temporarily storing the brake fluid when the brake pressure is reduced. A low pressure accumulator assigned to the circuit, each low pressure accumulator connected to the inlet of each pump element, and an auxiliary hydro unit for supplying brake pressure during traction control operation. Is provided,
The auxiliary hydro unit has a suction conduit leading from the brake fluid container to an inlet of a pump element of the return feed pump, and a charge valve arranged in the suction conduit, the charge valve including the suction conduit. Is opened at least during traction control and is shut off when the brake pedal is operated, and the auxiliary hydro unit has a switching valve, and the switching valve is connected to one brake circuit outlet of the master brake cylinder. A control valve assigned to the drive wheel outlet passage, the control valve being assigned to the master brake cylinder connection of the control valve, the control valve assigned to the drive wheel outlet passage being connected to the suction conduit. The pump element of the connected return feed pump is connected, and further, the control valve is In the type in which the connection conduit is shut off during the traction control operation and the master brake cylinder connection part of the control valve is connected to the brake fluid container via the pressure limiting valve, the auxiliary hydro unit ( 43) has a plunger (48) with a central valve (49) with which the piston is axially slidable in the working cylinder (50) against the return spring (52). (51) limits the control chamber (53) on the one hand and the pressure chamber (54) on the other hand, said pressure chamber being closed during sliding of the piston incorporated in said pressure piston (51) Valve (49)
Is connected to the plunger inlet (57) via the pressure chamber and is directly connected to the plunger outlet (58), and the plunger (48) is connected to the other brake circuit outlet of the master brake cylinder (15). (16) to the drive wheel (1
Located in a connecting conduit leading to said control valve (33) assigned to an outlet passage (23) for (2), wherein said plunger inlet (57) is connected to said other brake circuit outlet (16) The plunger outlet (5
8) is connected to the control valve (33), and the control chamber (53) of the plunger (48) is connected to the pressure limiting valve (4).
A hydraulic two-circuit braking device characterized by being connected to the inlet of 7). 2. The switching valve (46) is configured as a 3-port 2-position solenoid valve, and the first valve connection portion of the three controlled valve connection portions of the 3-port 2-position solenoid valve is Master brake cylinder connection (2) of the control valve (32)
6), the second valve connection is connected to the brake circuit outlet (17) of the master brake cylinder (15), and the third valve connection is the pressure limiting valve (47).
The first valve connection is connected to the second valve connection in the unexcited valve basic position and is connected to the inlet of the third valve in the actuated position produced by excitation. The hydraulic two-circuit brake device according to claim 1, wherein the three-port two-position solenoid valve is configured to be connected to the connecting portion. 3. The charge valve (45) is configured as a two-port two-position valve controlled hydraulically, and the hydraulic control inlet of the two-port two-position valve is a master brake cylinder (15). Is connected to the brake circuit outlet (17) of the
3. The hydraulic two-circuit braking device according to claim 1, wherein the hydraulic two-circuit braking device is configured to open in an uncontrolled basic position and to be closed in a switching position. 4. A hydraulically controlled two-port two-position valve (59) is connected in parallel to the pressure limiting valve (47), and a control inlet of the two-port two-position valve is a master brake cylinder ( 15) Brake circuit outlet (17)
4. The two-port two-position valve according to claim 1, wherein the two-port two-position valve is configured to open in an actuated position and closed in an uncontrolled basic position. Hydraulic two-circuit braking device. 5. Pump element (36) of the return feed pump (35) connected to the suction conduit (44).
The hydraulic two-circuit braking device according to any one of claims 1 to 4, wherein is a self-suction type. 6. A pre-charge pump (62) is arranged in the suction conduit (44), the pre-charge pump (62) having another pressure limit with an opening direction towards the brake fluid container (18). Hydraulic two-circuit braking device according to any one of claims 1 to 5, wherein the valves (63) are connected in parallel. 7. The front charge pump (62) comprises the suction conduit (18) between a brake fluid container (18) and a connection point of the pressure limiting valve (47) connected to the switching valve (46). 44) The hydraulic two-circuit braking device according to claim 6, which is located at 44). 8. The four-passage hydro unit (20) has four inlet passages (25, 26, 27, 28), and two inlet passages (26, 27) among the inlet passages.
Control valves (32,3) assigned to the outlet passages (22,23) for the drive wheels (11,12) in each brake circuit.
The master brake cylinder connection part of 3) is formed,
Master brake cylinder of a control valve (31, 33) with another two inlet passages (25, 28) assigned to the outlet passages (13, 14) for vehicle wheels (13, 14) not driven in each brake circuit The hydraulic two-circuit braking device according to any one of claims 1 to 7, wherein a connecting portion is formed. 9. The four-passage hydro unit (20)
′) Has two inlet passages (26, 27) which connect the master brake cylinder connection of each two control valves (31, 32; 33, 34) located in each brake circuit. And the exit passages (21, 2) for vehicle wheels that are not driven during traction control.
4. The control valve (31, 34) assigned to 4) is switched to the shut-off position.
The hydraulic two-circuit braking device described in the item.