JP2009149111A - Vehicular brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular brake device capable of adding the automatic braking function with a simple constitution while ensuring the independency of two brake lines from each other. <P>SOLUTION: The vehicular brake device includes first and second communication passages 101, 102 for respectively feeding compressed air in front and rear air tanks 3, 5 to a front wheel side and a rear wheel side when stepping in a brake pedal 7, a third communication passage 103 communicated with and connected to any one air tank, a directional control valve 23 for communicating or blocking the third communication passage 103, fourth and fifth communication passages 104, 105 connected to the downstream side of the third communication passage 103, a first double check valve 19 for selecting and outputting the air of higher pressure to be fed from the first communication passage 101 and the fourth communication passage 104, and a second double check valve 21 for selecting and outputting air of higher pressure to be fed from the second communication passage 102 and the fifth communication passage 105. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle brake device that is particularly suitable for use in an automatic brake that automatically performs braking.

Conventionally, an anti-lock brake system (ABS) that prevents a wheel from being locked during braking of a vehicle has been developed and put into practical use, and various techniques for improving such an ABS have been proposed ( For example, see Patent Documents 1 and 2 below)
Various techniques for adding a function of automatic braking to a vehicle brake device have also been proposed (see, for example, Patent Document 3 below). In the technique disclosed in Patent Document 3, an air reservoir tank for automatic braking is provided in addition to an air tank that stores normal braking air, and the reservoir tanks are respectively provided on the front and rear brake fluid flow paths. A connected technology is disclosed. In addition, a valve (proportional valve) whose opening can be changed by a controller, etc., is provided at the connection between the reservoir tank and the communication passage on the front and rear sides, and automatic braking by adjusting the opening of these valves. Is disclosed.
Japanese Patent Laid-Open No. 10-129447 JP-A-8-324401 JP 2003-276585 A

  However, in the technique disclosed in Patent Document 3, it is necessary to add two proportional valves in order to add an automatic braking function, resulting in an increase in cost. In addition, even when an automatic braking function is added to the conventional ABS-related technology as disclosed in Patent Documents 1 and 2, a problem is that valves are required for two independent brake systems, front and rear, respectively. There is.

  Such a problem will be described in more detail with reference to FIGS. 3 and 4. FIG. 3 is a schematic diagram showing a basic configuration of an air brake system using air as a working fluid. As shown in the figure, the brake system of an automobile is composed of two independent brake lines for the purpose of ensuring safety. In FIG. 3, a front brake for applying braking force to the front wheel side and a braking force for the rear wheel side are shown. It consists of two systems with the rear brake which gives.

When the driver depresses the brake pedal 7, the brake valve 9 is opened, pressurized air is supplied from the front air tank 3 to the front wheel side wheel brakes 11 and 13 through the communication path 2, and the rear air tank 5 communicates with the compressed air. Pressurized air is supplied to the rear-wheel wheel brakes 15 and 17 through the passage 4. Reference numerals 25 and 27 in the figure are ABS valves that release the wheel lock by reducing or releasing the supplied air pressure when the wheel is locked on a slippery road surface. An attempt to add an automatic brake function while maintaining the independence of the two brake lines results in a configuration as shown in FIG. 4, for example. In this case, air supply passages 6 and 8 are provided for supplying air for automatic braking from the front and rear air tanks 3 and 5, and these air supply passages 6 and 8 are provided via double check valves 19 and 21. Connected to air supply paths 2 and 4 for normal braking. The double check valves 19 and 21 are valves that open the flow path on the higher pressure side and communicate with the output port.

In addition, valves (electromagnetic valves) 22 and 24 for switching the open / close state based on control signals from a controller (not shown) are provided in the air supply passages 6 and 8 for automatic braking, respectively. Automatic braking can be realized by opening both together.
However, in this case, as described above, two valves 22 and 24 are required, resulting in an increase in cost. In addition, the brake device is provided with a plurality of valves (solenoid valves) such as ABS valves and traction control valves. Depending on the specifications and standards on the controller side, there are no margins in the output port from the controller. There is a problem that the controller itself cannot be added or the controller itself needs to be changed in order to add two solenoid valves.

In addition, the brake system of an automobile requires two brake lines to be independent from legal requirements. However, if the automatic braking valves shown in FIG. Sometimes the front and rear brake line systems become common, and it may not be possible to maintain independence.
The present invention was devised in view of such problems, and provides a vehicle brake device that can add an automatic braking function with a simple configuration while ensuring independence of two brake lines. The purpose is to do.

  For this reason, the vehicle brake device of the present invention has two independent brake systems on the front wheel side and the rear wheel side of the vehicle, and pressurized air as working fluid is respectively applied to the front wheel side and the rear wheel side. A braking device for a vehicle that applies braking force by supplying a first communication passage that supplies pressurized air in a front air tank to a front wheel side when the brake pedal is depressed, and an additional pressure in the rear air tank when the brake pedal is depressed. A second communication path for supplying pressurized air to the rear wheel side; a third communication path connected to either the front air tank or the rear air tank; and a third communication path provided on the third communication path. A switching valve capable of switching to a communication state in which at least the upstream side and the downstream side are communicated in the passage or a cutoff state in which the upstream side is shut off and the downstream side is opened to the atmosphere, and the downstream side of the third communication passage The branched fourth communication path and fifth communication path, and the air connected to the first communication path and the fourth communication path and supplied from the two communication paths are selected with the higher pressure. Select the first double check valve that outputs to the front wheel side and the higher pressure of the air that is connected to the second communication path and the fifth communication path and is supplied from the two communication paths. A second double check valve that outputs to the wheel side is provided (claim 1).

In addition, the rear wheel side of the vehicle is configured as a rear two-shaft type vehicle having front and rear axles, and the front axle of the rear two axles is a drive shaft for transmitting driving force from the engine, and the rear axle is It is preferable that the shaft is configured as a driven shaft to which the driving force is not transmitted.
In addition, a pressure reducing circuit that reduces the air pressure supplied to the driven shaft side during braking according to the load of the vehicle, and the driving shaft and the left and right wheels of the driven shaft are controlled regardless of the braking operation of the driver. A vehicle behavior control circuit that controls the behavior of the vehicle by individually applying power, the second check valve is provided on the upstream side of the decompression circuit, and when the switching valve is switched to the communication state At the same time, it is preferable that air is supplied to the vehicle behavior control circuit by operating the vehicle behavior control circuit.

  Further, the control means for controlling the operation of the switching valve has an obstacle detection means for detecting an obstacle ahead of the vehicle, and a time until the vehicle collides with the obstacle. It is preferable to provide a collision time prediction means for predicting, and when the collision time predicted by the collision time prediction means falls below a predetermined time, the switching valve is switched to the communication state and the braking force is automatically applied. Item 4).

  According to the vehicle brake device of the present invention, in the brake device having two brake systems independent on the front wheel side and the rear wheel side, the function of an automatic brake can be added by adding one switching valve. There is an advantage that an increase in cost can be significantly suppressed. In addition, since the two brake systems do not interfere with each other or affect each other, even if a failure such as air leakage occurs in one brake system, it does not affect the other brake system, and reliability A high system can be constructed. In addition, since the configuration is simple, there is an advantage that a highly reliable system can be constructed from this aspect as well (claim 1).

  In addition, the rear wheel side of the vehicle is configured as a rear two-shaft type vehicle having front and rear axles, and the front axle of the rear two axles is a drive shaft to which a driving force is transmitted from the engine, and the rear axle has the driving force. When applied to a vehicle configured as a driven shaft that is not transmitted, there is an advantage that a braking force by automatic braking can be applied to all three shafts including the front wheels by adding only one switching valve ( Claims 2 and 3).

  In addition to the above-mentioned advantages, when there is an obstacle ahead of the vehicle and a collision is predicted, it is possible to avoid the collision of the vehicle by automatically applying a braking force or reduce the impact, There is an advantage that a highly safe vehicle can be realized (claim 4).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
-Description of 1st Embodiment First, when the brake device for vehicles which concerns on 1st Embodiment of this invention is demonstrated, FIG. 1 is a schematic diagram which shows the principal part structure.
The vehicle 1 is provided with a brake device including two systems of brake lines capable of supplying working fluid independently to the front wheel side and the rear wheel side. In the present embodiment, the vehicle 1 is a truck having one axle on the front and rear sides, and air is applied as the working fluid of the brake device. Therefore, the vehicle 1 has a front air tank 3 as an air source for supplying pressurized air to the front wheel side wheel brakes 11 and 13 and an air source for supplying pressurized air to the rear wheel side wheel brakes 15 and 17. And a rear air tank 5.

In addition, an engine-driven compressor (not shown) is connected to each of the air tanks 3 and 5 so that air pressurized to a predetermined pressure by the compressor is supplied to the air tanks 3 and 5. It has become.
A first communication path 101 and a second communication path 102 are connected to each of the air tanks 3 and 5, and a brake valve 9 integrated with the brake pedal 7 is interposed in these communication paths 101 and 102. ing. Here, the brake valve 9 shuts off the communication passages 101 and 102 when the brake pedal 7 is not depressed, and opens the communication passages 101 and 102 according to the depression amount when the brake pedal 7 is depressed. When the brake valve 9 is opened, the pressurized air from the air tanks 3 and 5 is supplied to the wheel brakes 11 to 17.

Further, the vehicle 1 is provided with brake pipes 109 and 110, of which the brake pipe 109 is connected to the front wheel side wheel brakes 11 and 13, and the brake pipe 110 is connected to the rear wheel side wheel brakes 15 and 17. It is connected.
A first communication path 101 is connected to the brake pipe 109 via a first double check valve 19 and a communication path (sixth communication path) 106, which will be described later. A second communication path 102 is connected via a double check valve 21 and a communication path (seventh communication path) 107.

  Here, these double check valves (hereinafter referred to as DCV) 19 and 21 are known valves each having two input ports and one output port, and are working fluids input from the two input ports. The higher pressure is selected and output. Specifically, due to the difference in pressure of the working fluid from the two input ports, the internal valve body is pushed by the working fluid having a higher pressure so as to block the lower pressure input port (low pressure side input port). Further, when the low-pressure side input port is closed, the other input port (high-pressure side input port) and the output port are configured to communicate with each other.

  The downstream end of the first communication path 101 is connected to one input port of the first DCV 19, and the output port of the first DCV 19 and the front wheel side brake pipe 109 are connected by a communication path 106. Similarly, the downstream end of the second communication path 102 is connected to one input port of the second DCV 21, and the output port of the second DCV 21 and the rear wheel side brake pipe 110 are connected by the communication path 107.

  As shown in the figure, the rear air tank 5 is connected to a communication path (third communication path) 103 different from the second communication path 102, and the third communication path 103 is connected to the interior of the communication path 103. Is provided with a switching valve 23 that can be switched between a communication state and a cutoff state. Here, the third communication path 103 is connected to the rear air tank 5, but it may be connected to the front air tank 3 instead of the rear air tank 5, or may be connected to another tank provided.

  Further, the operation state of the switching valve 23 is controlled based on a control signal from an ABS-ECU (control means) 33 described later. The switching valve 23 is a solenoid type on-off valve that operates based on the on / off state of an electrical signal, and is configured as a normally closed type valve that shuts off the communication path 103 during normal operation (when the operation signal is off). Has been. Further, at the normal time, the downstream side of the switching valve 23 is opened to the atmosphere.

The third communication path 103 is branched into two communication paths on the downstream side, and the fourth communication path 104 and the fifth communication path 105 are connected to the branched communication paths. Of these, the downstream end of the fourth communication path 104 is connected to the other input port of the first DCV 19, and the downstream end of the fifth communication path 105 is connected to the other input port of the second DCV 21.
The front wheel side brake pipe 109 is provided with ABS valves 25 and 27 for preventing the front wheel from being locked. When the brake ABS valves 25 and 27 are turned on, the front wheel side brake pipe 109 is opened to the atmosphere. Thus, the supply of air to the front wheel brakes 11 and 13 can be reduced or cut off. An ABS valve having the same function as that of the front wheel side is also provided on the brake circuit on the rear wheel side, but illustration of this is omitted. The operating states of the front wheel side ABS valves 25 and 27 are also controlled based on a control signal from the ABS-ECU 33.

  Here, the ABS-ECU 33 will be described. Although not shown, the ABS-ECU 33 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and a TIM (Random Access Memory) connected to each other by a bidirectional bus. Timer), CPU (microprocessor), input port, output port, and the like. The ECU 33 is connected to sensors such as a wheel speed sensor (not shown) provided for each wheel and a brake switch (not shown) for detecting a driver's brake pedal operation.

When the ABS-ECU 33 detects the lock of the wheel during braking, the ABS valve of the locked wheel is operated to reduce the air pressure and prevent the wheel from being locked.
By the way, the vehicle 1 detects a front obstacle and determines that there is a possibility of a collision with the vehicle. Equipped with a functioning automatic brake device.

A collision damage mitigation system ECU 35 and an automatic brake ECU 37 for controlling the operation of these systems are provided, and the ABS-ECU 33 is configured to be able to communicate with these ECUs 35 and 37. These ECUs 33, 35, and 37 constitute a control means.
Among these, the automatic brake device mainly includes the above-described communication paths 103 to 105, the first and second DCVs 19 and 21, the switching valve 23, and the automatic brake ECU 37, and the ABS is based on a command signal from the automatic brake ECU 37. -When an operation control signal is output from the ECU 33 to the switching valve 23, the switching valve 23 is opened, so that air is supplied to the wheel brakes 11 to 17 and braking force is automatically applied to the vehicle 1. It is like that.

  Specifically, a laser radar, a stereo camera, or the like (not shown) is connected to the collision damage mitigation system ECU 35, and these are detected by obstacle detection means (not shown) provided in the collision damage mitigation system ECU 35. An obstacle ahead of the vehicle 1 is detected based on information from the sensors. When an obstacle is detected, a collision time predicting means (not shown) obtains a relative speed with respect to the obstacle based on information from a vehicle speed sensor or the like, and predicts a time for collision with the obstacle.

  Then, when the collision time predicted by the collision time predicting means becomes a predetermined time or less, it is determined that the collision of the vehicle 1 cannot be avoided. Based on the operation control signal from the ECU 35 for collision damage mitigation system A collision damage reduction system (not shown) is activated, and this information is transmitted from the collision damage reduction system ECU 35 to the automatic brake ABS 37. Based on this information, the automatic brake ABS 37 outputs a command signal to the ABS-ECU 33 to operate the automatic brake.

Thereby, the switching valve 23 is switched to the communication state, and braking force is automatically applied to the wheels on the front wheel side and the rear wheel side.
Since the vehicle brake device according to the first embodiment of the present invention is configured as described above, its operation will be described as follows. First, since the brake valve 9 is turned off during normal operation (when the automatic brake device is not activated), both the communication passages 101 and 102 are cut off. Therefore, no air is supplied downstream of the brake valve 9. Further, since the switching valve 23 is also off, the communication path 103 is also shut off, and no air is supplied downstream of the switching valve 23.

For this reason, air is not supplied to each DCV19, 21 from any path | route, the wheel brakes 11-17 will be in a non-operation state, and braking force does not act on each wheel.
On the other hand, during normal braking (during braking when the automatic brake device does not operate), the driver depresses the brake pedal 7 so that the brake valve 9 is opened and the first DCV 19 is opened from the front air tank 3 via the first communication passage 101. Air is supplied to the second DCV 21 from the rear air tank 5 via the second communication passage 102.

  At this time, since the switching valve 23 is off, the third communication path 103 is blocked, and no air is supplied downstream of the switching valve 23. Further, since the fourth communication path 104 and the fifth communication path 105 are open to the atmosphere, in the first DCV 19, the first communication path 101 and the sixth communication path 106 are connected and connected to the front wheel side via the brake pipe 109. Air is supplied to the wheel brakes 11 and 13, and a braking force corresponding to the depression of the brake pedal 7 acts on the front wheels. Similarly, in the second DCV 21, the second communication path 102 and the seventh communication path 107 are connected in communication, and air is supplied to the wheel brakes 15 and 17 on the rear wheel side via the brake pipe 110, so that the brake pedal The braking force corresponding to the depression of 7 acts on the rear wheels.

  Further, in the configuration according to the present embodiment, the brake system on the front wheel side and the brake system on the rear wheel side are physically communicated by the first DCV 19, the fourth passage 104, the fifth passage 105, and the second DCV 21, Since the fourth passage 104 and the fifth passage 105 are opened to the atmosphere by the switching valve 23, both brake systems are independent of each other. Therefore, even if a failure occurs in one brake system, the other brake system is not affected by the failure.

  Next, the action at the time of automatic braking will be described. For example, if the collision damage mitigation system ECU 35 determines that the collision of the vehicle cannot be avoided based on information from a laser radar, a stereo camera or the like (not shown), this damage reduction at the time of collision A collision damage mitigation system (not shown) is activated based on an operation control signal from the system ECU 35, and this information is transmitted from the collision damage mitigation system ECU 35 to the automatic brake ABS 37. Then, the automatic brake ABS 37 outputs a command signal for operating the automatic brake to the ABS-ECU 33 based on this information.

  Upon receiving this automatic brake signal, the ABS-ECU 33 outputs a control signal to the switching valve 23, whereby the switching valve 23 is opened and the inside of the third passage 103 is switched to the communication state. Accordingly, the rear air tank 5 and the first DCV 19 are connected via the third communication path 103 and the fourth communication path 104, and the rear air tank 5 and the second DCV 21 are connected via the third communication path 103 and the fifth communication path 105. Are connected in communication.

In this case, even if the driver does not operate the brake pedal 7, the functions of the DCVs 19 and 21 connect the fourth communication path 104 and the sixth communication path 106 on the front wheel side, and connect the rear wheel side. The fifth communication path 105 and the seventh communication path 107 are connected in communication.
Therefore, air is supplied from the air tank 5 to the wheel brakes 11 to 17 regardless of the driver's brake operation, and a braking force is forcibly applied to each wheel. Even during such automatic braking, when the wheel lock is detected, the ABS functions and the wheel lock is avoided.

  Therefore, according to the vehicle brake device according to the first embodiment of the present invention, by adding one switching valve 23 in the brake device having two brake systems independent on the front wheel side and the rear wheel side. There are advantages that can be added in the function of automatic brakes. That is, in order to establish an automatic brake while maintaining the independence of each brake system, normally, a path for short-circuiting the air tank and the wheel brake is provided on the front wheel side and the rear wheel side, respectively, and a switching valve is provided on this path. However, in the case of such a configuration, since a switching valve is required on each of the front wheel side and the rear wheel side, a total of two switching valves are required, resulting in an increase in cost. There is.

  On the other hand, in this apparatus, while having a simple configuration in which one switching valve 23 is provided, it is possible to realize the automatic braking while maintaining the independence of the two brake systems, thereby suppressing an increase in cost. There is an advantage that you can. That is, in this apparatus, air as working fluid is supplied to the two brake lines by one switching valve 23, but the front brake system and the rear brake system do not interfere with each other and affect each other. Therefore, even if a failure such as air leakage occurs in one brake system, the other brake system is not affected. Therefore, there is an advantage that a highly reliable system can be constructed. In addition, since the configuration of the present apparatus is extremely simple, there is an advantage that a highly reliable system can be constructed from this aspect.

Further, when there is an obstacle ahead of the vehicle 1 and a collision is predicted, the braking force is automatically applied to avoid the collision of the vehicle 1 or to reduce the damage when the collision occurs. There is an advantage that the safety of the vehicle can be improved.
-Description of 2nd Embodiment Next, when the vehicle brake device which concerns on 2nd Embodiment of this invention is demonstrated, FIG. 2 is a schematic diagram which shows the principal part structure.

  As shown in the figure, the vehicle to which the second embodiment is applied is a so-called double axle type (rear 2-axle type) vehicle in which the rear axle is formed of two axles, and the rear axle of the rear wheel. A rear front shaft 39 and a rear rear shaft 41 which is a rear axle of the rear wheel. Among these, the rear front shaft 39 is a drive shaft to which driving force is transmitted from an engine (not shown), The rear rear shaft 41 is a driven shaft (driven shaft) to which no driving force is transmitted.

  Also in such a vehicle 1, as in the first embodiment, a brake device having two systems of brake lines capable of independently supplying working fluid to the front wheel side and the rear wheel side is provided. On the rear wheel side, wheel brakes 15 and 17 are provided on the rear front shaft 39, and wheel brakes 16 and 18 are provided on the rear rear shaft 41. The rear wheel brake system includes these four wheels. Brakes 15 to 18 are provided.

  As shown in FIG. 2, the vehicle 1 is provided with a front air tank 3 and a rear air tank 5. Similarly to the first embodiment, a communication passage 101 (first communication passage) and a communication passage 102a are connected to the air tanks 3 and 5, respectively, and these communication passages 101 and 102a are integrated with the brake pedal 7. Brake valve 9 is interposed. The brake valve 9 is a known dual brake valve configured in the same manner as that described in the first embodiment.

  The vehicle 1 is provided with brake pipes 109 to 111, of which the brake pipe 109 is connected to the front wheel side wheel brakes 11 and 13. Further, one brake pipe 110 on the rear wheel side is connected to the wheel brakes 15 and 17 of the rear front shaft 39, and the other brake pipe 111 is connected to the wheel brakes 16 and 18 of the rear rear shaft 41.

During normal braking, pressurized air as working fluid is supplied from the front air tank 3 to the front wheel side wheel brakes 11 and 13, and pressurization as working fluid is applied from the rear air tank 5 to the rear wheel side wheel brakes 15 to 18. Air is supplied.
A first communication path 101 is connected to the brake pipe 109 on the front wheel side via a first double check valve (first DCV) 19 and a communication path (sixth communication path) 106.

In addition to the communication passage 102 a, a communication passage 102 b is connected to the rear air tank 5, and the downstream ends of these communication passages 102 a and 102 b are both connected to the relay valve 36. Among these, the downstream end of the communication path 102 a is connected to the signal input port of the relay valve 36, and the downstream end of the communication path 102 b is connected to the input port of the relay valve 36.
The relay valve 36 is provided with two output ports, and communication paths 102c and 102d are connected to these output ports, respectively. The downstream side of one of the communication paths 102c is a path for supplying air to the wheel brakes 15 and 16 of the rear left wheel, and the downstream side of the other communication path 102d is This is configured as a route for supplying air to the wheel brakes 17 and 18 of the right wheel.

Here, the relay valve 36 is provided to enhance the response at the time of air supply to the rear side. In this embodiment, when the signal pressure is input from the communication path 102a, the input port is opened. Thus, the communication path 102b and the communication paths 102c and 102d are connected in communication.
Further, in the communication path 102d, a communication path 102e branches in the middle, and this communication path 102e is connected to one input port of the second double check valve (second DCV) 21 on the downstream side. Further, a fifth communication path 105 described later is connected to the other input port. And these 2nd communicating path is comprised by these communicating paths 102a-102e. A seventh communication path 107 is connected to the output port of the second DCV.

By the way, in the brake system downstream of the relay valve 36, there is a pressure reducing circuit 61 for preventing the rear rear shaft 41, which is a driven shaft, from being locked at the time of braking along with the reduction of the load load, and the behavior of the vehicle 1. If it is determined that the vehicle tends to be unstable, a vehicle behavior control circuit 63 that prevents the unstable behavior of the vehicle 1 by individually controlling the left and right braking forces is provided.
These circuits 61 and 63 are known techniques, but will be briefly described below. The decompression circuit 61 is mainly composed of a load sensing proportioning valve (hereinafter simply referred to as LSPV) 43. The LSPV 43 is connected to the output port of the second DCV 21 through the seventh communication path 107.

Here, the LSPV 43 is configured to mechanically detect the deflection amount of the rear suspension (that is, the load on the rear wheel side) and reduce the brake pressure as the rear wheel side load is reduced. By properly distributing the braking force between the front and rear wheels, the rear wheel, in particular, the rear rear shaft 41 is prevented from being locked, and the braking stability is maintained. Therefore, the LSPV 43 is provided on the downstream side of the relay valve 36, and the air pressure output via the relay valve 36 is reduced by the LSPV 43 and output to the wheel brakes 16 and 18 of the rear rear shaft 41. In FIG. 2, the communication path 102e input to the LSPV 43 is branched from the communication path 102d on the right wheel side, but may be branched from the communication path 102c on the left wheel. Further, if there is an empty output port of the relay valve 36, the communication path 102e may be directly connected to the relay valve 36.

Further, the air pressure supply paths to the left and right wheels are independent on the downstream side of the LSPV 43, and the left wheel side pressure reducing path 112 and the right wheel side pressure reducing path 113 are connected to the LSPV 43, respectively. These decompression paths 112 and 113 are both connected to input ports of known double cut-off valves (DCOVs) 45 and 47.
Here, the double cut-off valves (DCOV) 45 and 47 are configured as valves having functions opposite to the double check valves (DCV) 19 and 21 described in the first embodiment. That is, the DCVs 19 and 21 are configured to select and output the higher working pressure of the working fluid input from the two input ports, whereas the DCOVs 45 and 47 are input from the two input ports. Among the working fluids, the one with the lower pressure is selected and output.

  The other input ports of the DCOVs 45 and 47 are connected to communication paths 114 and 115 for supplying air output via the vehicle behavior control circuit 63. In addition, ABS valves 49 and 51 are interposed in the communication passages 114 and 115, respectively, and the communication passages 116 and 117 are branched from the communication passages 114 and 115 on the downstream side of the ABS valves 49 and 51, respectively. Yes. The branched communication paths 116 and 117 are connected to the wheel brakes 15 and 17 on the front wheel side.

When the brake ABS valves 49 and 51 are turned on, the downstream communication passage is opened to the atmosphere, and the supply of air can be reduced or cut off to reduce the braking force.
On the other hand, communication paths 121 and 122 are connected to the output ports of the DCOVs 45 and 47, respectively, and these communication paths 121 and 122 are connected to the wheel brakes 16 and 18 of the rear rear shaft 41 via the brake pipe 111. .

  Therefore, the lower air pressure of the air pressure reduced by the LSPV 43 and the air pressure supplied via the vehicle behavior control circuit 63 acts on the wheel brakes 16 and 18 of the rear rear shaft 41 as the brake pressure. Thus, it is possible to prevent the wheel brakes 16 and 18 of the rear rear shaft 41 from being supplied with an air pressure higher than the air pressure corresponding to the rear wheel load, thereby avoiding the locking of the wheels of the rear rear shaft 41. It has become.

Next, the vehicle behavior control circuit 63 will be briefly described. The vehicle behavior control circuit 63 is mainly composed of two DCVs 53 and 55 and an ASR valve 57. Here, the air output from the relay valve 36 is input to one input port of the DCVs 53 and 55 through the communication paths 102c and 102d, respectively.
The communication passage 102b connected to the rear air tank 5 has a communication passage 118 branched near its downstream end, and an ASR valve 57 is interposed in the communication passage 118. Further, the communication path 118 is branched into two communication paths 119 and 120 on the downstream side of the ASR valve 57, and the downstream end of these branched communication paths 119 and 120 is connected to the other input port of the DCVs 53 and 55. It is connected.

  Here, the ASR valve 57 is a solenoid-type on-off valve that operates based on on / off of an electrical signal, and shuts off the communication path 118 during normal time (when the operation signal is off). When the ABS-ECU 33 determines that the behavior of the vehicle 1 tends to be unstable (for example, spin tendency), a control signal is output to open the ASR valve 57 and the ASR valve 57 is opened. It is like that. As a result, when the behavior of the vehicle 1 tends to become unstable, the pressurized air from the rear air tank 5 is supplied to the DCVs 53 and 55 regardless of the operation state of the relay valve 36 and the downstream side of the DCVs 53 and 55 is connected. Air can be supplied to the passages 115 and 116. In this case, the operations of the ABS valves 49 and 51 are individually controlled as necessary, and the attitude control of the vehicle 1 is executed so that the left and right wheels are in a desired braking state.

Incidentally, in the second embodiment, the front air tank 3 is connected to a third communication path 103 different from the first communication path 101. As described in the first embodiment, the third communication path 103 is provided with a switching valve 23 that can switch the inside of the third communication path 103 to a communication state or a cutoff state.
The operation state of the switching valve 23 is controlled based on a control signal from the ABS-ECU 33. The switching valve 23 is a solenoid type on-off valve that operates based on the on / off state of an electrical signal, and is configured as a normally closed type valve that shuts off the communication path 103 during normal operation (when the operation signal is off). Has been. Further, at the normal time, the downstream side of the switching valve 23 is opened to the atmosphere.

Further, the third communication path 103 is branched into two communication paths (fourth communication path and fifth communication path) 104, 105 on the downstream side thereof, and the downstream end of the fourth communication path 104 is the above-described one. The other input port of the first DCV 19 is connected, and the downstream end of the fifth communication path 105 is connected to the other input port of the second DCV 21.
The front wheel side brake pipe 109 is provided with ABS valves 25 and 27 for preventing the front wheel from being locked. When the brake ABS valves 25 and 27 are turned on, the front wheel side brake pipe 109 is opened to the atmosphere. Thus, the supply of air to the front wheel brakes 11 and 13 can be reduced or cut off.

  Also in the second embodiment, in addition to the ABS-ECU 33, the collision damage mitigation system ECU 35 and the automatic brake ECU 37 are provided as in the first embodiment. Since it is the same structure, the overlapping description is abbreviate | omitted. In this embodiment, the ASR valve 57 is provided, but the operation of the ASR valve 57 is also controlled based on a control signal from the ABS-ECU 33.

Since the vehicle brake device according to the second embodiment of the present invention is configured as described above, its operation will be described as follows.
First, during normal operation (during non-braking), since the brake valve 9 is off, both the communication passages 101 and 102a are cut off. Therefore, no air is supplied downstream of the brake valve 9. For this reason, the relay valve 36 is also turned off, and air is not supplied to the downstream side of the relay valve 36.

Further, since the switching valve 23 is also off, the communication path 103 is also shut off, and no air is supplied downstream of the switching valve 23. For this reason, air is not supplied to each DCV19, 21 from any path | route, the wheel brakes 11-18 will be in a non-operation state, and braking force does not act on each wheel.
On the other hand, during normal braking, when the driver depresses the brake pedal 7, the brake valve 9 is opened and air is supplied from the front air tank 3 to the first DCV 19 via the first communication path 101. Also, an input signal is input from the rear air tank 5 to the relay valve 36 via the communication path 102a, and the relay valve 36 is turned on.

As a result, air is supplied to the second DCV 21 via the communication path 102b, the relay valve 36, the communication path 102d, and the communication path 102e.
At this time, since the switching valve 23 is off, the third communication path 103 is blocked, and no air is supplied downstream of the switching valve 23. Further, since the fourth communication path 104 and the fifth communication path 105 are open to the atmosphere, in the first DCV 19, the first communication path 101 and the sixth communication path 106 are connected and connected to the front wheel side via the brake pipe 109. Air is supplied to the wheel brakes 11 and 13, and a braking force corresponding to the depression of the brake pedal 7 acts on the front wheels.

  In the second DCV 21, the communication path 102 e and the communication path 107 are connected to each other, and the air decompressed according to the rear wheel load in the LSPV 43 is supplied to one input port of the DCOVs 45 and 47 through the communication paths 112 and 113. The Further, the air output from the DCVs 53 and 55 is supplied to the other ports of the DCOVs 45 and 47. In this case, the air pressure supplied through the LSPV 43 is lower unless the ABS valves 49 and 51 are operated. Supply to wheel brakes 16,18.

On the rear front shaft 39 side, the air output via the DCVs 53 and 55 is output to the wheel brakes 15 and 17 via the communication paths 114 and 115 and the communication paths 116 and 117.
As described above, during normal braking, air corresponding to the depression of the brake pedal 7 is supplied to the front front and rear wheels 39 of the front and rear wheels, and air reduced in accordance with the load is supplied to the rear rear shaft 41. Thus, a braking force acts on the vehicle 1.

  At this time, as in the first embodiment, the brake system on the front wheel side and the brake system on the rear wheel side are physically communicated by the first DCV 19, the fourth passage 104, the fifth passage 105, and the second DCV 21. Since the fourth passage 104 and the fifth passage 105 are opened to the atmosphere by the switching valve 23, both brake systems are independent from each other, and both brake systems do not affect each other due to failure.

  Further, during automatic braking, as in the first embodiment, when it is determined that the collision of the vehicle 1 cannot be avoided in the collision damage mitigation system ECU 35, it is illustrated based on the operation control signal from the collision damage mitigation system ECU 35. The collision damage mitigation system is activated, and this information is transmitted from the collision damage mitigation system ECU 35 to the automatic brake ABS 37. Then, the automatic brake ABS 37 outputs a command signal for operating the automatic brake to the ABS-ECU 33 based on this information.

  When the ABS-ECU 33 receives this automatic brake signal, it outputs a control signal to the switching valve 23, whereby the switching valve 23 is opened and the inside of the third passage is switched to the communication state. As a result, even if the driver has not operated the brake pedal 7, the front air tank 3 and the first DCV 19 are connected via the third communication path 103 and the fourth communication path 104, and the wheel brake 11 on the front wheel side, Air is supplied to 13.

  Further, the front air tank 3 and the second DCV 21 are connected in communication via the third communication path 103 and the fifth communication path 105. As a result, even if the driver does not operate the brake pedal 7, the function of the DCV 21 connects the fifth communication path 105 and the seventh communication path 107 on the rear wheel side, and the air decompressed by the LSPV 43 is connected. Is supplied to the DCOVs 45 and 47 through the communication passages 112 and 113. The DCOVs 45 and 47 are also supplied with air that has not been decompressed by opening the ASR valve 57 as will be described later.

Then, by the function of the DCOVs 45 and 47 for selecting and outputting the low pressure side, the air decompressed according to the loaded load is supplied from the DCOVs 45 and 47 to the wheel brakes 16 and 18 of the rear rear shaft 41.
On the other hand, at the time of such automatic braking, the ASR valve 57 is switched on simultaneously with the switching valve 23 being turned on. By controlling the ASR valve 57 in this way, the ASR valve 57 can function as a switching valve for realizing automatic braking. That is, when the ASR valve 57 is turned on, the air in the rear air tank 5 is communicated with the communication passage 102b, the communication passage 118, the communication passages 119 and 120, the communication passages 114 and 115, the DCV 53, regardless of whether the brake pedal 7 is operated. 55, the communication passages 114, 115 and the communication passages 115, 116 are supplied to the wheel brakes 15, 17 of the rear front shaft 39. Accordingly, the braking force can be automatically applied to the wheels of the rear front shaft 39.

  Accordingly, by simultaneously opening the ASR valve 57 together with the switching valve 23 during automatic braking, air is supplied from the air tank 3 to the wheel brakes 11 to 18 regardless of the driver's brake operation, and all the wheels are forcibly forced. A large braking force can be obtained by applying the braking force. Even during such automatic braking, the ABS functions when the wheel lock is detected, so that the wheel lock can be reliably avoided.

  As described above in detail, according to the vehicle brake device according to the second embodiment of the present invention, in the brake device having two brake systems independent on the front wheel side and the rear wheel side, one switching valve is provided. By adding the function of an automatic brake, there is an advantage that an increase in cost can be suppressed and there is an advantage that a highly reliable system can be constructed because the configuration is simple.

  In particular, the rear rear shaft 41 is prevented from being locked in a rear two-shaft three-axis vehicle as in the second embodiment, in which the rear front shaft 39 is configured as a drive shaft and the rear rear shaft 41 is configured as a driven shaft. In order to do so, a pressure reducing circuit including the LSPV 43 is required, so that the air pressure supplied to the two axles of the rear wheels is different. For this reason, it becomes difficult to provide one switching valve for the rear two shafts and supply air simultaneously during automatic braking.

  It is conceivable to deal with such a problem by providing a switching valve for each of the rear front shaft 39 and the rear rear shaft 41. However, with this configuration, there are three switching functions including the front wheel side. A valve is required, which increases costs. Furthermore, in such a case, three output ports are required on the ECU side that controls the switching valve in order to correspond to each switching valve, but the cost increases accordingly.

On the other hand, as in the present embodiment, air is supplied to the front wheel side and the rear rear shaft 41 with a single switching valve, and the ASR valve 57 originally provided for the rear front shaft 39 is provided. By using it, there is an advantage that a braking force by automatic braking can be applied to all three axes without any change in the ECU.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in each embodiment described above, the switching valve 23 is configured as an on / off valve that switches the third communication path 103 to the communication state or the cutoff state. However, the switching valve 23 can switch at least the communication state or the cutoff state. It is sufficient that a valve whose opening degree can be appropriately adjusted between fully open and fully closed may be applied, or the opening degree may be substantially adjusted by duty control of the on / off valve. Also good.

  Various modifications can be made to the detailed configuration of the brake circuit. For example, also in the first embodiment, a brake circuit may be configured using a relay valve in order to increase the response at the time of brake operation, or a brake circuit may be configured using a relay valve on the front wheel side of the second embodiment. Also good.

It is a typical brake circuit diagram explaining the principal part structure of the brake device for vehicles which concerns on 1st Embodiment of this invention. It is a typical brake circuit diagram explaining the principal part structure of the brake device for vehicles which concerns on 2nd Embodiment of this invention. It is a figure explaining the brake circuit of a common vehicle. It is a brake circuit figure devised in the creation process of this application, and is a figure explaining a subject of this application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 3 Front air tank 5 Rear air tank 7 Brake pedal 9 Brake valve 11, 13, 15-18 Wheel brake 19 1st double check valve 21 2nd double check valve 23 Switching valve 33 ABS-ECU (control means)
35 ECU for collision damage mitigation system (control means)
37 Automatic brake ECU (control means)
39 Rear front axle (front axle)
41 Rear rear axle (rear axle)
61 Pressure reducing circuit 63 Vehicle behavior control circuit 101 First communication path 102 Second communication path 103 Third communication path 104 Fourth communication path 105 Fifth communication path

Claims (4)

A vehicle brake having two independent brake systems on the front wheel side and the rear wheel side of the vehicle, and applying a braking force by supplying pressurized air as a working fluid to the front wheel side and the rear wheel side, respectively. A device,
A first communication passage for supplying pressurized air in the front air tank to the front wheels when the brake pedal is depressed;
A second communication path for supplying pressurized air in the rear air tank to the rear wheel when the brake pedal is depressed;
A third communication path that is connected in communication with either the front air tank or the rear air tank;
A switching valve provided on the third communication path and capable of switching to a communication state where at least the upstream side and the downstream side are communicated with each other in the third communication path or a cutoff state where the upstream side is blocked and the downstream side is opened to the atmosphere ,
A fourth communication path and a fifth communication path respectively connected to the downstream side of the third communication path;
A first double check valve connected to the first communication path and the fourth communication path, for selecting the higher pressure of the air supplied from the two communication paths and outputting it to the downstream front wheel side;
A second double check valve connected to the second communication path and the fifth communication path, for selecting the higher pressure of the air supplied from the two communication paths and outputting it to the downstream rear wheel side; A brake device for a vehicle, comprising: The rear wheel side of the vehicle is configured as a rear two-shaft type vehicle having front and rear axles, and the front axle of the rear two axles is a drive shaft for transmitting driving force from the engine, and the rear axle is the drive 2. The vehicle brake device according to claim 1, wherein the vehicle brake device is configured as a driven shaft to which no force is transmitted. A pressure reducing circuit for reducing the air pressure supplied to the driven shaft during braking according to the load of the vehicle;
A vehicle behavior control circuit that controls the behavior of the vehicle by individually applying a braking force to the left and right wheels of the drive shaft and the driven shaft regardless of the driver's braking operation,
The second check valve is provided upstream of the pressure reducing circuit;
3. The vehicle brake device according to claim 2, wherein when the switching valve is switched to the communication state, the vehicle behavior control circuit is simultaneously operated to supply air to the vehicle behavior control circuit. Having control means for controlling the operation of the switching valve;
The control means includes
Obstacle detection means for detecting an obstacle ahead of the vehicle;
A collision time predicting means for predicting the time until the vehicle collides with the obstacle;
4. The braking force is automatically applied by switching the switching valve to a communication state when the collision time predicted by the collision time predicting means becomes a predetermined time or less. The vehicle brake device according to the item.

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