JP4802706B2 - Electronically controlled hydraulic brake system - Google Patents

Description

  The present invention relates to a hydraulic brake system for a vehicle, and more particularly to an electronically controlled hydraulic brake system in which the hydraulic pressure of a wheel cylinder of a brake that suppresses the rotation of a wheel is controlled by an electronic control device.

In the electronically controlled hydraulic brake system, for example, as described in Patent Document 1 below, the operation state of the brake operation member is detected by the operation state detection device, and based on the detection result, at the time of pressure increase, The brake fluid of the power hydraulic pressure source is supplied to the front wheel cylinder and the rear wheel cylinder by the front pressure increasing valve and the rear pressure increasing valve, respectively, and at the time of pressure reduction, the brake fluid of the front wheel cylinder and the rear wheel cylinder is discharged by the front pressure reducing valve and the rear pressure reducing valve. Some types are allowed to flow out into the reservoir.
JP 2002-541010 Gazette JP-A-6-156243

In this type of electronically controlled hydraulic brake system, low-frequency noise may occur when the brake operating member is released, particularly when it is rapidly released. As a result of pursuing this cause, it has been found that the pulsation of the front pressure reducing passage connecting the front pressure reducing valve and the reservoir is transmitted to the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir. The reason is presumed as follows. In the conventional electronically controlled hydraulic brake system, the front decompression passage and the rear decompression passage are joined and then connected to the reservoir. In other words, the front decompression passage and the rear decompression passage have a common part. Since the front brake has a larger wheel cylinder than the rear brake, when the pressure is reduced simultaneously by releasing the brake operation member, the flow rate of the brake fluid discharged from the front wheel cylinder is larger than that of the rear wheel cylinder. Discharge from the wheel cylinder is hindered by brake fluid discharged from the front wheel cylinder. In this state, if a pulsation of hydraulic pressure is generated by the throttle portion present in the front pressure reducing passage, it is estimated that the pulsation is transmitted from the common portion to the rear pressure reducing passage and abnormal noise is generated. Alternatively, it is estimated that the pulsation is transmitted to the rear decompression passage in the following case. When decompression is performed simultaneously on the front side and the rear side, the flow of brake fluid in the rear decompression passage merges with the flow of brake fluid in the front decompression passage at the connection point of both the front and rear decompression passages. At that time, pulsation occurs, and the pulsation is transmitted more strongly from the front side to the rear side with a small flow rate, or the pulsation generated in the front decompression passage is transmitted more strongly to the rear decompression passage with a small flow rate than in the front decompression passage, In the rear decompression passage, an abnormal noise that causes discomfort to the occupant is generated. Alternatively, although the pulsation is transmitted not only to the rear decompression passage but also to the front decompression passage, the abnormal noise generated in the former may be greater than the abnormal noise in the latter, or at least it may cause more discomfort to the passenger. I don't know.
In any case, it is presumed that the occurrence of the abnormal noise is that the pulsation of the brake fluid is transmitted from the junction between the front decompression passage and the rear decompression passage to the brake fluid in the rear decompression passage.

As a result of various experiments based on the above assumption, the present invention has been achieved.
The present invention includes (a) an operation state detection device that detects an operation state of a brake operation member, and (b) a front pressure increasing valve, a rear pressure increasing valve, a front pressure reducing valve, and a rear A pressure reducing valve, (c) a power hydraulic pressure source connected by a pressure increasing passage common to the front pressure increasing valve and the rear pressure increasing valve, (d) the front pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve, and Each of the rear pressure reducing valves is electrically connected to each of the operation state detecting devices, and based on the detection result of the operation state detecting device, the front pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve, and the rear pressure reducing valve and a hydraulic control device for controlling each of the pressure increase, the front pressure-increasing valve and the brake fluid front wheel cylinder and Riyahoirushi of the power hydraulic pressure source by the rear booster valve Are respectively supplied to the cylinder, during decompression, the said form front pressure reducing valve and the brake fluid of the front wheel cylinder and the rear wheel cylinder by the rear pressure reducing valve is caused to respectively flow to the reservoir respectively via the front pressure decreasing passage and the rear pressure decreasing passage In the electronically controlled hydraulic brake system, the power hydraulic pressure source, the front pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve, and the rear pressure reducing valve are assembled in an integrated block, and the front pressure reducing valve, the reservoir, The front pressure reducing valve and the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir are respectively formed in the block respectively on the front pressure reducing valve and the rear pressure reducing valve side. The front decompression passage and the rear decompression passage It is an Abstract that bets is connected to the reservoir independently of each other.

If the electronically controlled hydraulic brake system is configured as described above, it is possible to prevent or reduce the generation of abnormal noise when the brake operating member is released.

Aspects of the Invention

The following invention which is considered claimable (hereinafter under "claimable invention" may be referred to. Claimable invention is an invention described in the scope of the billed "present invention" Some aspects of the concept concept invention, the superordinate concept of the invention of the present application, or an invention of another concept) are exemplified and described below. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

In addition, some of the following paragraphs are no longer the invention described in the claims or the subordinate concept thereof due to the amendment, but they are useful for understanding the invention described in the claims. This information is included, so it will be left as it is.

(1) The operation state of the brake operation member is detected by the operation state detection device, and based on the detection result, at the time of pressure increase, the brake fluid of the power hydraulic pressure source is supplied to the front wheel cylinder and the rear by the front pressure increase valve and the rear pressure increase valve. Electrons of a type that are supplied to the wheel cylinders, respectively, and at the time of pressure reduction, the front pressure reducing valve and the rear pressure reducing valve cause the brake fluid of the front wheel cylinder and the rear wheel cylinder to flow out to the reservoir through the front pressure reducing passage and the rear pressure reducing passage, respectively. In the control hydraulic brake system,
An electronically controlled hydraulic brake comprising: a transmission suppressing means for suppressing a pulsation of brake fluid from being transmitted to a brake fluid in a rear decompression passage from a junction between the front decompression passage and the rear decompression passage. system.
(2) The front pressure reducing passage connecting the front pressure reducing valve and the reservoir and the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir are connected to the reservoir independently of each other. The electronically controlled hydraulic brake system according to item (1), wherein an independent connection form constitutes the transmission suppressing means.
Thus, if the front decompression passage and the rear decompression passage are connected to the reservoir independently of each other so that they do not have a common portion, even if pulsation occurs in the front decompression passage, the pulsation is caused by the reservoir. It is absorbed and is not transmitted to the rear decompression passage. In addition, when pulsation occurs due to the joining of the brake fluid in the front decompression passage and the rear decompression passage, the occurrence of pulsation itself is avoided and eventually transmission of the pulsation to the rear decompression passage is prevented.
(3) One of the front decompression passage and the rear decompression passage is connected to a suction passage connecting the suction side of the power hydraulic pressure source and the reservoir, and is connected to the reservoir via the suction passage; The electronically controlled hydraulic brake system according to item (2), wherein the other is directly connected to the reservoir.
Thus, if the suction passage for the power hydraulic pressure source to suck the brake fluid is used as one of the front decompression passage and the rear decompression passage, the configuration of the fluid passage can be simplified.
(4) The front pressure reducing passage connecting the front pressure reducing valve and the reservoir and the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir are connected to the reservoir after joining. At least one of the front pressure reducing valve and the rear pressure reducing valve side portion from the junction of the front pressure reducing passage and the rear pressure reducing passage is provided with a transmission suppressing device that suppresses transmission of the pulsation to the rear pressure reducing passage. (1) The electronically controlled hydraulic brake system described in item (1).
In this aspect, the configuration in which the front decompression passage and the rear decompression passage have a common part is the same as the conventional one, but at least one of the front decompression valve and the rear decompression valve side portion from the junction of the front decompression passage and the rear decompression passage. By providing a transmission restraining device, the brake fluid pulsation is prevented from being transmitted to the rear decompression passage. The configuration of the liquid passage can be simplified more than in the above item (3).
(5) The transmission suppressing device includes a check valve provided in the rear pressure reducing passage and allowing a flow of brake fluid from the rear pressure reducing valve to the reservoir but preventing a reverse flow. Electronically controlled hydraulic brake system as described in
If a check valve is provided in the rear decompression passage, the pulsation of the brake fluid can be prevented from being transmitted to the rear decompression passage. The check valve is desirably provided at a position close to the junction of the rear decompression passage with the front decompression passage. This is because pulsation is prevented from being transmitted to most of the rear decompression passage. The check valve may have a spring that biases the valve element toward the valve seat, or may not have a spring and the valve element may be seated on the valve seat with its own weight. Is possible. The former is desirable from the viewpoint of satisfactorily performing the check valve's backflow prevention function (pulsation transmission suppressing function), and the latter is desirable from the viewpoint of less impeding the flow of brake fluid in the rear decompression passage.
(6) The transmission suppressing device is provided in at least one of the front pressure reducing valve and the rear pressure reducing valve side portion from the junction of the front pressure reducing passage and the rear pressure reducing passage, and absorbs at least one pulsation thereof. The electronically controlled hydraulic brake system according to (4) or (5), including a damper device.
If the damper device is installed in the front decompression passage, it is possible to avoid the occurrence of pulsation in the front decompression passage itself, or to eliminate or reduce the pulsation once generated, thereby suppressing transmission to the rear decompression passage. Can do. Further, if the damper device is provided in the rear decompression passage, the pulsation transmitted to the rear decompression passage can be eliminated or reduced. Therefore, it is desirable to provide the damper device at a position as close as possible to the junction of the rear decompression passage with the front decompression passage.
(7) At least the front pressure reducing valve and the rear pressure reducing valve are attached to an integral block, and ends of the front pressure reducing passage and the rear pressure reducing passage on the front pressure reducing valve and the rear pressure reducing valve side are The electronically controlled hydraulic brake system according to any one of items (1) to (6) formed in the block.
According to each aspect of this section and the following, it is possible to configure the connection passages of the constituent elements at a low cost as compared with the case where the constituent elements of the hydraulic brake system are connected by pipe lines, and thus the hydraulic pressure The cost of the brake system can be reduced.
(8) The electronically controlled hydraulic pressure according to (7), wherein the power hydraulic pressure source, the front pressure increasing valve, and the rear pressure increasing valve are attached to the block, and a fluid passage that connects them is formed in the block. Brake system.
(9) The front pressure reducing passage connecting the front pressure reducing valve and the reservoir and the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir are connected to the reservoir independently of each other, and the block The reservoir is connected by a discharge pipe and a suction pipe, and one of the front decompression passage and the rear decompression passage is formed in the block and forms the suction passage in cooperation with the suction pipe. The electronically controlled hydraulic brake system according to (7) or (8), wherein the electronic control hydraulic brake system is connected to a portion and the other is mainly composed of the discharge pipe.
(10) At least the front pressure reducing valve and the rear pressure reducing valve are attached to an integral block, and the front pressure reducing valve and the end of the rear pressure reducing passage on the side of the front pressure reducing valve and the rear pressure reducing valve are at the end. The electronically controlled hydraulic brake system according to item (5), wherein the electronically controlled hydraulic brake system is formed in a block, and the check valve is provided in a portion formed in the block.
If a check valve is provided in the block, the connection between the rear pressure reducing passage and the check valve is facilitated. Further, when a part of the block is used as the main body of the check valve, the check valve itself can be configured at low cost.
(11) At least the front pressure reducing valve and the rear pressure reducing valve are attached to an integral block, and ends of the front pressure reducing passage and the rear pressure reducing passage on the side of the front pressure reducing valve and the rear pressure reducing valve are The electronically controlled hydraulic brake system according to (6), wherein the damper device is formed in a block, and the damper device is connected to at least one of an end of a front decompression passage and a rear decompression passage formed in the block.
If a damper device is provided in the block, the connection between the rear decompression passage and the damper device is facilitated. In addition, when a part of the block is used as the main body of the damper device, the damper device itself can be configured at low cost.
(12) The transmission suppressing means performs a pressure reducing operation of at least one of the front pressure reducing valve and the rear pressure reducing valve when both the hydraulic pressure of the front wheel cylinder and the hydraulic pressure of the rear wheel cylinder are reduced. The electronically controlled hydraulic brake system according to any one of (1) to (11), including a pressure reducing operation suppressing unit for suppressing.
When both the hydraulic pressure of the front wheel cylinder and the hydraulic pressure of the rear wheel cylinder are reduced, if the pressure reduction of at least one of the two hydraulic pressures is suppressed, the pulsation of the brake fluid flowing out from the front wheel cylinder is caused by the rear wheel. Transmission to the brake fluid flowing out from the cylinder can be suppressed. Alternatively, if pulsation occurs when the brake fluid flow in the rear decompression passage merges with the brake fluid flow in the front decompression passage at the connection point of both the front and rear decompression passages, Can be suppressed.
(13) The electronically controlled hydraulic brake system according to the item (12), wherein the pressure reducing operation suppressing unit operates while the vehicle on which the electronically controlled hydraulic brake system is mounted is stopped.
The suppression of the decompression operation in the item (12) can be performed even while the vehicle is traveling. However, since it is inevitable that some influence will be exerted on the driving feeling (change in deceleration) of the vehicle, the deceleration is 0, there is no effect of suppressing the decompression operation, and there is little background noise. It is desirable to do this only when the vehicle is in a state where loud sounds can be heard.
(14) The rear pressure reducing operation in which the pressure reducing operation suppressing unit prohibits the pressure reducing operation of the rear pressure reducing valve until the hydraulic pressure of the front wheel cylinder drops below a threshold hydraulic pressure determined according to the hydraulic pressure of the rear brake cylinder. The electronically controlled hydraulic brake system according to (12) or (13), which includes an operation prohibition section.
While the pressure reducing operation of the rear pressure reducing valve is prohibited, the pulsation of the brake fluid flowing out from the front wheel cylinder is rarely transmitted to the brake fluid flowing out from the rear wheel cylinder. In addition, when pulsation occurs due to the merge of the brake fluid flow in the rear decompression passage and the brake fluid flow in the front decompression passage, the occurrence of the pulsation itself can be suppressed. Abnormal noise generated by the transmission of pulsation increases when the hydraulic pressure in the front wheel cylinder is relatively large relative to the hydraulic pressure in the rear wheel cylinder. If the pressure reducing operation of the rear pressure reducing valve is prohibited until the pressure drops below the threshold fluid pressure determined accordingly, the generation of abnormal noise can be effectively suppressed.
The threshold hydraulic pressure is preferably set to increase as the hydraulic pressure of the rear brake cylinder increases, and the following (20) is a typical one, but is not indispensable. It is also possible to select from a value in the range of 115 to 85% of the above, or to set a larger or smaller value that is set from a range of 20 to 5% of the hydraulic pressure difference between the front wheel cylinder and the rear wheel cylinder. is there.
(15) The rear pressure reducing operation prohibiting portion is activated when a target pressure reducing gradient of the front wheel cylinder determined based on an operating state of the brake operating member is equal to or larger than a set gradient, and is not activated when smaller than the set gradient. The electronically controlled hydraulic brake system described in (14).
When the target pressure reduction gradient of the front wheel cylinder is small, the brake fluid flowing out from the front wheel cylinder has little effect on the brake fluid flowing out from the rear wheel cylinder. .
(16) The electronically controlled hydraulic brake system according to (12) or (13), wherein the pressure reducing operation suppressing unit includes a front pressure reducing gradient suppressing unit that suppresses a pressure reducing gradient by the front pressure reducing valve.
Since the abnormal noise generated by the transmission of pulsation becomes large when the pressure reduction gradient of the hydraulic pressure of the front wheel cylinder is large, the generation of the noise can be effectively suppressed by providing a front pressure reduction gradient suppressing portion. .
(17) The front pressure reducing gradient suppressing unit suppresses the pressure reducing gradient by the front pressure reducing valve until the hydraulic pressure of the front wheel cylinder drops below a threshold hydraulic pressure determined according to the hydraulic pressure of the rear brake cylinder ( The electronically controlled hydraulic brake system according to item 16).
Abnormal noise generated by the transmission of pulsation increases when the hydraulic pressure in the front wheel cylinder is high, until the hydraulic pressure in the front wheel cylinder drops below the threshold hydraulic pressure determined by the hydraulic pressure in the rear brake cylinder. If the pressure reduction gradient of the hydraulic pressure of the front wheel cylinder is suppressed, the generation of abnormal noise can be effectively suppressed.
(18) The electronically controlled hydraulic brake according to (16) or (17), wherein the front decompression gradient suppression unit operates when a target decompression gradient of the hydraulic pressure of the front wheel cylinder is equal to or greater than a set decompression gradient. system.
As described above, the noise generated by the transmission of pulsation increases when the pressure reduction gradient of the hydraulic pressure of the front wheel cylinder is large. If it operates when it is equal to or higher than the set decompression gradient, useless suppression of the decompression gradient can be avoided.
(19) The electronically controlled hydraulic brake system according to any one of (16) to (18), wherein the front decompression gradient suppressing unit includes an upper limit regulating unit that regulates an upper limit of the decompression gradient of the front wheel cylinder.
(20) The electronic control hydraulic pressure according to any one of (16) to (18), wherein the front pressure reducing gradient suppressing unit includes a gain reducing unit that reduces a control gain of an electronic control unit that controls the front pressure reducing valve. Brake system.
(21) The electronically controlled hydraulic brake system according to (14) or (17), wherein the threshold hydraulic pressure is the hydraulic pressure itself of the rear wheel cylinder.

  Several embodiments of the claimable invention will now be described in detail with reference to the drawings. In addition to the following examples, the claimable invention can be practiced in various modifications based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. .

  FIG. 1 shows an electronically controlled hydraulic brake system as an embodiment of the claimable invention. The brake system shown in FIG. 1 includes a brake pedal 10 as a brake operation member, a master cylinder 12, a power hydraulic pressure source 14, brakes 16 to 19 provided respectively corresponding to wheels located on the left and right and front and rear. The brakes 16 and 17 are left and right front wheel brakes, and the brakes 18 and 19 are left and right rear wheel brakes. The brakes 16 to 19 are hydraulic brakes that are operated by the hydraulic pressure of the wheel cylinders (brake cylinders) 20 to 23.

  The master cylinder 12 includes two pressure pistons, and hydraulic pressure corresponding to the operation force is generated in the pressure chambers in front of the two pressure pistons by the operation of the brake pedal 10 by the driver. Be made. The left and right front wheel cylinders 20 and 21 are connected to the two pressurizing chambers of the master cylinder 12 via master passages 26 and 27, respectively. Master cutoff valves 29 and 30 are provided in the middle of the master passages 26 and 27, respectively. The master shut-off valves 29 and 30 are normally open electromagnetic on-off valves.

  In addition, four wheel cylinders 20 to 23 are connected to the power hydraulic pressure source 14 via a pressure increasing passage 36. The wheel cylinders 20 to 23 are supplied with hydraulic pressure from the power hydraulic pressure source 14 while being disconnected from the master cylinder 12, and the hydraulic brakes 16 to 19 are operated. The hydraulic pressure of the wheel cylinders 20 to 23 is controlled by a hydraulic pressure control valve device 38 including a plurality of electromagnetic control valves such as master cutoff valves 29 and 30.

  In this embodiment, as shown in FIG. 2, the power hydraulic pressure source 14, the hydraulic control valve device 38, etc. are unitized and provided in one integral block 39. 1 is a unit 40, a liquid passage is formed inside the block 39, and an electromagnetic fluid pressure control valve, a pump and the like are connected to each other through the liquid passage. Held in a state. Since the hydraulic pressure of the wheel cylinders 20 to 23 is controlled by the power hydraulic pressure source 14 and the hydraulic pressure control valve device 38 included in the unit 40 and the hydraulic brakes 16 to 19 are operated, the unit 40 is hereinafter referred to as the hydraulic pressure. This is referred to as a control actuator 40.

Two pressure chambers of the master cylinder 12 are connected to the ports 42 and 43 (only the port 42 is shown in FIG. 2) of the hydraulic control actuator 40, respectively, and the wheel cylinders 20 to 23 are connected to the ports 44 to 47, respectively. Connected. Portions between the ports 42 and 43 of the liquid passages 26 and 27 and the master cylinder 12 are master connection passages 48FL and 48FR. The ports 44 to 47 and the wheel cylinders 20 to 20 of the pressure increase passage 36 are provided. 23 are wheel cylinder connection passages 49FL, 49FR, 49RL, and 49RR. A reservoir 52 is connected to the reservoir connection port 50 via a reservoir hose 51. The reservoir 52 is a low-pressure container and stores the working fluid at atmospheric pressure.

The power hydraulic pressure source 14 includes a pump device including a pump 56 and a pump motor 58 that drives the pump 56. The pump 56 is connected to the reservoir connection port 50 through the suction passage 60 and is connected to an accumulator 62. The hydraulic fluid in the reservoir 52 is pumped up by the pump 56, supplied to the accumulator 62, and stored in a pressurized state. The passage in the reservoir hose 51 also constitutes a part of the suction passage 60.
The accumulator 62 and the suction side of the pump 56 are connected by a relief passage 66, and a relief valve 68 is provided in the relief passage 66. The relief valve 68 switches from the closed state to the open state when the hydraulic pressure of the accumulator 62 on the high pressure side or the hydraulic pressure of the hydraulic fluid discharged from the pump 56 exceeds the set pressure.

  The hydraulic control valve device 38 includes front-wheel and rear-wheel pressure-increasing linear valves 72 and 73 provided in the pressure-increasing passage 36, a front-wheel side pressure-reducing linear valve 76 provided in the front pressure-reducing passage 74, and a rear And a pressure reducing linear valve 80 on the rear wheel side provided in the pressure reducing passage 78. The front decompression passage 74 connects the decompression linear valve 76 and the reservoir 52. The rear pressure reducing passage 78 connects the pressure reducing linear valve 80 and the reservoir 52. In this embodiment, the rear pressure reducing passage 78 is provided in the middle of the suction passage 60 connecting the suction side of the power hydraulic pressure source 14 and the reservoir 52. It is connected. That is, the rear decompression passage 78 is connected to the reservoir 52 through the suction passage 60, while the front decompression passage 74 is directly connected to the reservoir 52, and is connected to the reservoir 52 independently of each other. Although not shown in FIG. 2, the block 39 is provided with a reservoir connection port 90 similar to the reservoir connection port 50, and the reservoir connection port 50 is provided by a reservoir hose 51 constituting a suction pipe, The connection ports 90 are respectively connected to the reservoirs 52 by discharge hoses 92 that form the main body of the front decompression passage 74.

  The hydraulic pressure of the front wheel cylinders 20 and 21 is controlled by a pressure increasing linear valve 72 and a pressure reducing linear valve 76, and the hydraulic pressure of the rear wheel wheel cylinders 22 and 23 is controlled by a pressure increasing linear valve 73 and a pressure reducing linear valve 80. Be controlled. By controlling these pressure increasing linear valves 72 and 73 and pressure reducing linear valves 76 and 80, the hydraulic pressures of the wheel cylinders 20 to 23 are independently controlled. The front wheel side and rear wheel side pressure increasing linear valves 72 and 73 and the front wheel side pressure reducing linear valve 76 are normally closed valves, and the rear wheel side pressure reducing linear valve 80 is a normally open valve.

  On the other hand, a stroke simulator device 180 is provided in the master passage 26. The stroke simulator device 180 includes a stroke simulator 182 and a normally-closed simulator opening / closing valve 184. The opening / closing of the simulator opening / closing valve 184 causes the stroke simulator 182 to be disconnected from the communication state connected to the master cylinder 12. And can be switched. In the present embodiment, when the hydraulic brakes 16 to 19 are in a state where they are actuated by the hydraulic fluid from the power hydraulic pressure source 14, the hydraulic brakes 16 to 19 are opened. In some cases it is closed.

  The brake device is controlled based on a command from the brake ECU 200 as a hydraulic pressure control device. The brake ECU 200 mainly includes a computer, and includes an execution unit 202, a storage unit 204, an input / output unit 206, and the like. Connected to the input / output unit 206 are a brake switch 210, a stroke sensor 211, a master pressure sensor 214, a brake hydraulic pressure sensor 216, a wheel speed sensor 218 for detecting the rotational speed of each wheel, a hydraulic pressure source hydraulic pressure sensor 220, and the like. In addition, the pressure-increasing linear valves 72 and 73, the pressure-decreasing linear valves 76 and 80, the master shut-off valves 29 and 30, the electromagnetic control valves such as the simulator on-off valve 184, the pump motor 58 and the like are connected via a drive circuit (not shown). Has been.

  During normal braking, the master cutoff valves 29 and 30 are closed to disconnect the wheel cylinders 20 to 23 from the master cylinder 12, and the hydraulic brakes 16 to 19 are operated by the hydraulic pressure of the power hydraulic pressure source 14. It is done. At the same time, the stroke simulator 182 communicates with the master cylinder 12 to give the driver a feeling of operation. Based on the operation stroke detected by the stroke sensor 211, the master cylinder hydraulic pressure detected by the master pressure sensor 214, etc., the driver's required braking force is obtained, and the wheel cylinder hydraulic pressure target is obtained so that the required braking force is obtained. The hydraulic pressure is determined. The current supplied to the solenoids of the pressure-increasing linear valves 72 and 73 and the pressure-decreasing linear valves 76 and 80 is controlled so that the actual wheel cylinder hydraulic pressure becomes the same as the target hydraulic pressure. When the pressure is increased, the brake fluid of the power hydraulic pressure source 14 is supplied to the wheel cylinders 20 to 23 by the pressure-increasing linear valves 72 and 73, respectively, and when the pressure is reduced, the brake fluid of the wheel cylinders 20 to 23 is supplied by the pressure-decreasing linear valves 76 and 80. Each is discharged to the reservoir 52. In the power hydraulic pressure source 14, the pump motor 58 is controlled and the pump 56 is operated so that the hydraulic pressure detected by the hydraulic pressure source hydraulic pressure sensor 220 is within the set range.

  In the present embodiment, the stroke sensor 211 and the master pressure sensor 214 constitute an operation state detection device. The pressure increasing linear valve 72 constitutes a front pressure increasing valve, the pressure increasing linear valve 73 constitutes a rear pressure increasing valve, the pressure reducing linear valve 76 constitutes a front pressure reducing valve, and the pressure reducing linear valve 80 constitutes a rear pressure reducing valve. Yes. Further, a form in which the front decompression passage 74 and the rear decompression passage 78 are connected to the reservoir 52 independently of each other constitutes a transmission suppressing means.

In the present embodiment, the front decompression passage 74 and the rear decompression passage 78 are connected to the reservoir 52 independently of each other, so that, as shown in FIG. When Pfr and the hydraulic pressure Prr in the rear decompression passage are lowered, the pulsation of the hydraulic pressure Prr in the rear decompression passage, which is caused by the pulsation of the brake fluid being transmitted to the rear decompression passage, is prevented.
In contrast to the present embodiment, the rear decompression passage may be directly connected to the reservoir 52 and the front decompression passage may be connected to the suction passage 60 in the middle.

  FIG. 4 shows an electronically controlled hydraulic brake system as another embodiment. However, the same components as those in the embodiment shown in FIG. 1 and FIG. The hydraulic control valve device 250 of the brake system shown in FIG. 4 includes front-wheel and rear-wheel pressure-increasing linear valves 72 and 73 provided in the pressure-increasing passage 36 and front-wheel-side air pressure in the front pressure-reducing passage 252. A pressure reduction linear valve 76 and a rear wheel side pressure reduction linear valve 80 provided in the rear pressure reduction passage 254 are included. The front decompression passage 252 and the rear decompression passage 254 connect the decompression linear valves 76 and 80 and the reservoir 52, respectively. In this embodiment, after the front decompression passage 252 and the rear decompression passage 254 merge, the common part is connected to the suction passage 60 that connects the suction side of the power hydraulic pressure source 14 and the reservoir 52. .

  Further, a check valve 260 is provided in the rear pressure reducing passage 254 at a portion closer to the pressure reducing linear valve 80 than the junction. That is, the check valve 260 is provided in the block 39. The check valve 260 allows the flow of the brake fluid from the pressure-reducing linear valve 80 toward the reservoir 52, but prevents the reverse flow so that the pulsation of the brake fluid is caused by the front pressure-reducing passage 252 and the rear pressure-reducing passage 254. Is prevented from being transmitted to the rear decompression passage 254 side from the merging point. The check valve 260 is provided at a position as close as possible to the junction point of the rear decompression passage 254, and transmission of pulsation to most of the rear decompression passage 254 is prevented. Therefore, it is avoided as much as possible to prevent the brake fluid from being discharged from the pressure reducing linear valve 80. The check valve 260 constitutes a transmission suppressing device.

As shown in FIG. 5, the transmission suppressing device can be configured by a damper device 280. In the illustrated example, the damper device 280 is provided at a position on the pressure reducing linear valve 80 side of the rear pressure reducing passage 254 with respect to the front pressure reducing passage 252 and as close as possible to the front pressure reducing passage 252. Yes. In the illustrated damper device 280, a piston 284 is slidably fitted into a cylinder bore 282 formed in the block 39, and is urged by an elastic member 286 in a direction to reduce the volume of the liquid chamber 288. It is supposed to be. However, it is made of a rubber bag, and the bag is elastically inflated so that the volume of the liquid chamber inside increases, or the liquid chamber communicated with the rear decompression passage 254 is made of rubber. It is also possible to employ a damper device or the like in which a bag filled with compressed gas is disposed and the volume of the liquid chamber increases with the elastic contraction of the rubber bag.
In any case, the pulsation transmitted to the rear decompression passage 254 from the junction of the front decompression passage 252 and the rear decompression passage 254 can be attenuated by the damper device 280.
It is also possible to provide a damper device 280 in the front decompression passage 252.

  It is not indispensable that the power hydraulic pressure source 14, the hydraulic pressure control valve device 38, and the like are provided in one integral block to be unitized. For example, the power hydraulic pressure source 14, the hydraulic pressure control valve device 38, It is also possible to apply the present invention to a type in which each is provided in a separate block, a brake system in which at least one is not provided in the block, or the like.

  The above is an embodiment in which the generation of abnormal noise is suppressed by hardware, but the generation of abnormal noise can also be suppressed by software, that is, by improving the control of the pressure reducing operation of the pressure reducing linear valves 76 and 80. An example is shown in FIG. FIG. 6 shows that the required braking force of the driver is obtained based on at least one of the operation stroke detected by the stroke sensor 211 and the master cylinder hydraulic pressure detected by the master pressure sensor 214 so that the required braking force can be obtained. For suppressing the pulsation of the brake fluid from being transmitted to the rear decompression passage 78 from the junction of the front decompression passage 74 and the rear decompression passage 78 from the fluid pressure control program for controlling the fluid pressure of the wheel cylinders 20 to 23. Only the part is taken out and shown. The hydraulic pressure control program is stored in the storage unit 204 of the brake ECU 200 and is executed by the execution unit 202.

  First, in S11, whether or not the vehicle is stopped based on whether or not the vehicle speed V obtained based on the rotational speeds of the front, rear, left and right wheels detected by the wheel speed sensor 218 is 0, and the master pressure sensor 214 is detected. It is determined whether or not the master cylinder hydraulic pressure Pm detected is decreasing, and if any determination result is NO, the execution of S12 to 14 is skipped and the process returns to the main routine (not shown). If both the determination results are YES, S12 is executed and the hydraulic pressure Pfwc of the front wheel cylinders 20 and 21 (specifically, the detected values of the two brake hydraulic pressure sensors 216 corresponding to the wheel cylinders 20 and 21). Is greater than the hydraulic pressure Prwc of the rear wheel cylinders 22, 23 (specifically, the average value of the detected values of the two brake hydraulic pressure sensors 216 corresponding to the wheel cylinders 22, 23), and Then, it is determined whether or not the depressurization gradient | ΔPfwc / ΔT | of the hydraulic pressure Pfwc of the front wheel cylinders 20 and 21 is larger than the set depressurization gradient α. If the result of both determinations is YES, the rear decompression linear valve 80 is brought into a closed state or close to a closed state in S13. The “nearly closed state” means that the opening of the rear pressure reducing linear valve 80 is set to 30% or less or 20% or less (for example, a current that is 80% of the valve closing current, which is a closing current, is supplied). The opening is set to 20%). While the decompression gradient of the front wheel cylinders 20 and 21 is larger than the set decompression gradient α and the hydraulic pressure of the front wheel cylinders 20 and 21 is larger than the hydraulic pressure of the rear wheel cylinders 22 and 23, the rear wheel cylinder The decompression of 22 and 23 is prohibited or at least strongly suppressed.

On the other hand, if any result of the above determination is NO, the rear pressure-reducing linear valve 80 is opened in S14. If the hydraulic pressure Pfwc of the front wheel cylinders 20 and 21 is smaller than the hydraulic pressure Prwc of the rear wheel cylinders 22 and 23, the pulsation of the brake fluid is caused from the junction of the front decompression passage 74 and the rear decompression passage 78 to the rear decompression passage. 78, and even if the pressure reduction gradient | ΔPfwc / ΔT | of the front wheel cylinders 20 and 21 is smaller than the set pressure reduction gradient α, the possibility of pulsation transmission is low, so the rear wheel cylinder 22 and 23 are allowed to be depressurized.
In this embodiment, it is well avoided that the pulsation of the brake fluid is transmitted to the rear decompression passage 78 from the junction of the front decompression passage 74 and the rear decompression passage 78, and the generation of abnormal noise is prevented.

  In this embodiment, the portion of the brake ECU 200 that executes S11 to S13 is a threshold hydraulic pressure (in this embodiment, the hydraulic pressure of the front wheel cylinders 20, 21 is determined according to the hydraulic pressure of the rear wheel cylinders 22, 23). Constitutes a rear pressure reducing operation prohibiting section for prohibiting the pressure reducing operation of the rear linear pressure reducing valve 80 until the pressure drops below the hydraulic pressure of the rear wheel cylinder itself). The rear pressure reducing operation prohibiting section includes S11, and is operated while the vehicle is stopped, and the liquid in the front wheel cylinders 20 and 21 is set by setting the conditions regarding the front pressure reducing gradient in S12. It operates when the target pressure reduction gradient is equal to or greater than the set pressure reduction gradient.

  In the flowchart of FIG. 6, if the determination result in S12 is once YES, the execution of S12 continues for a certain period of time, for example, while a preset number of cycles and a pulsation suppression routine are executed. It is also possible to change the rear decompression linear valve 80 to be “open” after the execution of S13 is terminated after a certain period of time.

FIG. 7 shows another embodiment that suppresses the generation of abnormal noise in terms of software. This pulsation suppression routine is also stored in the storage unit 204. From the hydraulic pressure control program executed in the execution unit 202, the pulsation of the brake fluid is detected from the junction of the front pressure reducing passage 74 and the rear pressure reducing passage 78. Only the portion for suppressing transmission to 78 is shown.
First, in S21 and S22, the same determination as in S11 and S12 is performed. If the determination results in S21 and S22 are both YES, the target pressure reduction gradient of the front wheel cylinders 20 and 21 is guarded in S23. Temporary provision of the wheel cylinders 20 and 21 corresponding to a change in the driver's required braking force determined based on at least one of the operation stroke detected by the stroke sensor 211 and the master cylinder hydraulic pressure detected by the master pressure sensor 214 When the target decompression gradient is larger than the guard gradient β, the final target decompression gradient is determined as the guard gradient β. When the temporary target decompression gradient is smaller than the guard gradient β, the temporary target decompression gradient is directly used as the final target decompression gradient. It is done. If the determination result in S22 is NO, in S24, the guard against the decompression gradient is released. When the provisional target pressure reduction gradient is smaller than the guard gradient β, or when the hydraulic pressure Pfwc of the front wheel cylinders 20 and 21 is smaller than the hydraulic pressure Prwc of the rear wheel cylinders 22 and 23, the front pressure reduction passage 74 and the rear pressure reduction passage. Since the possibility that the pulsation of the brake fluid is suppressed and transmitted to the rear decompression passage 78 from the junction point with 78 is low, normal decompression control is performed.
Also in the present embodiment, it is possible to satisfactorily avoid the brake fluid pulsation being transmitted to the rear decompression passage 78 from the junction of the front decompression passage 74 and the rear decompression passage 78, and the generation of abnormal noise is suppressed.

In the present embodiment, the portion of the brake ECU 200 that executes S21 to S23 constitutes an upper limit restricting portion that restricts the upper limit of the decompression gradient of the front wheel cylinder. By including S22, the hydraulic pressure of the front wheel cylinder The pressure reduction gradient by the front pressure reducing valve is suppressed until the pressure drops below the threshold hydraulic pressure determined in accordance with the hydraulic pressure of the rear brake cylinder (in this embodiment, the hydraulic pressure of the rear wheel cylinder itself). In addition, the upper limit restricting unit includes S21, and is operated during the stop of the vehicle, and the target depressurization gradient of the hydraulic pressure of the front wheel cylinder is determined by setting the conditions regarding the front depressurization gradient in S22. Is activated when the pressure is greater than or equal to the set pressure reduction gradient. And this upper limit control part is an example of the front pressure reduction gradient suppression part which suppresses the pressure reduction gradient by a front pressure reduction valve.
Further, the rear decompression operation prohibiting unit and the front decompression gradient suppressing unit are examples of the decompression operation suppressing unit, respectively.

1 is a circuit diagram of an electronically controlled hydraulic brake system that is an embodiment of the claimable invention. FIG. It is a perspective view which shows the external appearance of the hydraulic control actuator which is a component of the said electronically controlled hydraulic brake system. It is a graph which shows notionally the pulsation of the rear decompression passage which occurred conventionally. It is a circuit diagram of the electronically controlled hydraulic brake system which is another Example. It is a circuit diagram of the electronically controlled hydraulic brake system which is another Example. It is a flowchart showing the pulsation suppression routine implemented in the electronically controlled hydraulic brake system which is another Example. It is a flowchart showing the pulsation suppression routine implemented in the electronically controlled hydraulic brake system which is another Example.

Explanation of symbols

10: Brake pedal 12: Master cylinder 14: Power hydraulic pressure source 16, 17, 18, 19: Brake 20, 21, 22, 23: Wheel cylinder 38: Hydraulic control valve device 39: Block 40: Unit 51: Reservoir hose 52: Reservoir 60: Suction passage 72, 73: Pressure increasing linear valve 74: Front pressure reducing passage 76: Pressure reducing linear valve 78: Rear pressure reducing passage 80: Pressure reducing linear valve 92: Discharge hose 211: Stroke sensor 214: Master pressure sensor 250: Fluid pressure control valve device 252: Front pressure reducing passage 254: Rear pressure reducing passage 260: Check valve 280: Damper device

Claims (3)

An operation state detection device for detecting an operation state of the brake operation member;
A front pressure increasing valve, a rear pressure increasing valve, a front pressure reducing valve and a rear pressure reducing valve, which are solenoid valves that can be operated independently,
A power hydraulic pressure source connected by a common pressure increasing passage to the front pressure increasing valve and the rear pressure increasing valve;
Each of the front pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve and the rear pressure reducing valve is electrically connected to the operation state detecting device, and the front pressure increasing valve is based on the detection result of the operation state detecting device. A fluid pressure control device for controlling each of the pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve, and the rear pressure reducing valve;
Include, in the pressure increase, the brake fluid of the front booster valve and the power hydraulic pressure source by the rear pressure-increasing valve is supplied to the front wheel cylinder and the rear wheel cylinder, during decompression, the front pressure reducing valve and the rear pressure reducing valve In the electronically controlled hydraulic brake system of the type in which the brake fluid of the front wheel cylinder and the rear wheel cylinder is discharged to the reservoir through the front decompression passage and the rear decompression passage, respectively,
The front hydraulic pressure source, the front pressure increasing valve, the rear pressure increasing valve, the front pressure reducing valve, and the rear pressure reducing valve are assembled in an integral block, and the front pressure reducing passage connecting the front pressure reducing valve and the reservoir; The front pressure reducing valve and the rear pressure reducing valve side of the rear pressure reducing passage connecting the rear pressure reducing valve and the reservoir are respectively formed in the block, and the front pressure reducing passage and the rear pressure reducing passage are connected to the rear pressure reducing valve. An electronically controlled hydraulic brake system, characterized in that a passage is connected to the reservoir independently of each other.   One of the front decompression passage and the rear decompression passage is connected to a suction passage connecting the suction side of the power hydraulic pressure source and the reservoir, and is connected to the reservoir through the suction passage, and the other is connected to the reservoir. The electronically controlled hydraulic brake system according to claim 1 connected directly to the reservoir.   The block and the reservoir are connected by a discharge pipe and a suction pipe, and one of the front decompression passage and the rear decompression passage is formed in the block and cooperates with the suction pipe to form the suction passage. The electronically controlled hydraulic brake system according to claim 2, wherein the other is mainly composed of the discharge pipe.

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