JP2005162176A - Brake hydraulic pressure control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid stagnation of gas in a hydraulic pressure circuit in a brake hydraulic pressure control device with a pump. <P>SOLUTION: Brake liquid pumped up from a reservoir 30 through an intake passage 76 by the pump 70 and stored in an accumulator 72 is supplied to a brake cylinder 14, and brake cylinder pressure is controlled by opening/closing control of pressure increasing/reducing solenoid valves 42, 44. A pressure reducing valve 110 provided in a return passage 100 for returning the brake liquid of the brake cylinder 14 to the reservoir 30 is opened in a state that hydraulic pressure in a pressure reducing solenoid valve 44 side exceeds a set valve opening pressure and is higher than that in an intake passage 76 side, and allows a flow of the brake liquid from the pressure reducing solenoid valve 44 to the intake passage 76. The pressure reducing valve 110 is closed in a closed state of the pressure reducing solenoid valve 44, and transmission of intake negative pressure to the pressure reducing solenoid valve 44 is cut off at the time of operation of the pump. Leaving of bubbles generated due to reduction of pressure of the brake liquid when the pressure reducing solenoid valve 44 is opened, is avoided. A damper is provided in the return passage 100, and generation of the intake negative pressure may be suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brake fluid pressure control device equipped with a pump, and more particularly to measures against suction negative pressure during pump operation.

  Examples of the brake fluid pressure control device include a device including a reservoir, a pump, and an electromagnetic valve device as described in Patent Documents 1 and 2. The electromagnetic valve device includes a pressure increasing electromagnetic opening / closing valve provided in a liquid passage connecting the pump and a brake cylinder of the brake, and a pressure reducing electromagnetic opening / closing valve provided in a return passage connecting the brake cylinder and the reservoir. The brake fluid pumped up from the reservoir by the pump is supplied to the brake cylinder via the pressure increasing electromagnetic on-off valve, so that the brake cylinder pressure, which is the hydraulic pressure of the brake cylinder, is increased, and the brake pressure is increased via the pressure reducing electromagnetic on-off valve. Brake cylinder pressure is decreased by discharging brake fluid from the cylinder to the reservoir.

In such a brake fluid pressure control device equipped with a pump, the fluid pressure before and after the operation of the pump fluctuates, causing vibrations and abnormal noise. Therefore, in the brake fluid pressure control device described in Patent Document 1, a damper device is provided on the discharge side of the pump so as to absorb pressure fluctuations accompanying the discharge of brake fluid.
JP-A-6-127359 JP-T-2001-527485

However, it is desirable to suppress pressure fluctuations on the suction side of the pump. For example, if a negative pressure is generated as the brake fluid is sucked, bubbles generated by aeration may remain in the brake fluid, as will be described in detail later.
The present invention has been made in view of the above circumstances, and an object of the present invention is to avoid accumulation of gas in a hydraulic circuit in a brake hydraulic pressure control device including a pump.

  The present invention includes: (a) a reservoir in which the internal pressure is maintained at substantially atmospheric pressure and storing brake fluid; (b) a pump that pumps brake fluid directly from the reservoir through the intake passage and supplies the brake fluid to the brake cylinder; c) A brake having a pressure reducing solenoid valve provided in a return passage connecting the brake cylinder to the suction passage, allowing the brake fluid to flow out from the brake cylinder to the reservoir and reducing the hydraulic pressure of the brake cylinder. A hydraulic pressure control device that allows a flow of brake fluid from the pressure-reducing solenoid valve to the suction passage and that suppresses transmission of suction negative pressure of the pump to the pressure-reducing solenoid valve. A suppression device is included.

The internal pressure of the reservoir is maintained at substantially atmospheric pressure by, for example, a pressure adjusting device such as a relief valve provided on a lid that closes the opening of the reservoir.
"Directly from the reservoir" means that there are no components other than the suction passage forming member such as a rubber hose, pipe, joint member, etc. between the pump and the reservoir, and the suction port of the pump and the reservoir are always in communication. Alternatively, it means that the brake fluid does not pass through the valve or the like until the brake fluid is sucked into the pump from the reservoir. The return passage is connected to the suction passage, but is outside the suction passage, and the brake fluid pumped from the reservoir by the pump does not pass through a part of the return passage.
The brake fluid pumped from the reservoir by the pump is stored, for example, under pressure in an accumulator, and may be supplied to the brake cylinder by being controlled to an appropriate height by a solenoid valve for pressure increase. It may be supplied. In the latter case, the brake cylinder pressure is controlled to an appropriate height by controlling the operation of the pump.

As will be described later, the suppression of the suction negative pressure is allowed to occur, but it is achieved by blocking the generated suction negative pressure from being transmitted to the pressure reducing solenoid valve, or the suction negative pressure is suppressed. This is achieved by suppressing the generation of pressure itself. In any case, by suppressing the transmission of the suction negative pressure to the pressure reducing solenoid valve, for example, the occurrence of bubbles in the brake fluid is suppressed.
In this brake fluid pressure control device, the return passage is connected to the suction passage, and the brake fluid discharged from the brake cylinder through the pressure reducing solenoid valve returns to the reservoir through a part of the return passage and the suction passage. Part of the intake passage also serves as the return passage. When the pump is operated, the brake fluid is pumped from the reservoir through the suction passage. However, the brake fluid discharged from the pressure reducing solenoid valve to the return passage may be directly sucked into the pump. The internal pressure of the reservoir is maintained at almost atmospheric pressure, but if negative suction pressure is generated due to the inertia of the brake fluid itself or the flow path resistance of the suction path or return path, it is transmitted to the return path and further reduced. Is transmitted to the solenoid valve. As a result, bubbles are generated inside the pressure reducing solenoid valve and the return passage, or bubbles generated inside the pressure reducing solenoid valve when the brake cylinder pressure is reduced may remain in the brake fluid. The pressure reducing solenoid valve is opened when the hydraulic pressure in the brake cylinder is reduced, but the hydraulic pressure on the brake cylinder side is higher than the hydraulic pressure on the suction passage side than the pressure reducing solenoid valve in the return passage. The flow rate of the brake fluid in the vicinity of the valve element of the pressure reducing solenoid valve increases, the pressure decreases locally, and aeration is generated in which air dissolved in the brake fluid becomes bubbles. At this time, if the hydraulic pressure in the portion immediately downstream of the pressure reducing solenoid valve is equal to or higher than atmospheric pressure, once generated bubbles immediately dissolve into the brake fluid and disappear, but the suction negative pressure is reduced with the operation of the pump. If generated and transmitted to the pressure reducing solenoid valve, the generated bubbles are likely to remain without dissolving in the brake fluid.
On the other hand, in this brake fluid pressure control device, since the transmission of the suction negative pressure to the pressure reducing solenoid valve is suppressed, even if the pressure reducing solenoid valve is opened during the pump operation, the downstream portion of the fluid is controlled. Even if the pressure is kept above atmospheric pressure or lower than atmospheric pressure, it is negligible. For this reason, the generated bubbles immediately dissolve into the brake fluid, and it is well avoided that they remain. In addition, in the state where the pressure reducing solenoid valve is closed, the generation of bubbles in the brake fluid due to the suction negative pressure of the pump being transmitted to the return passage and the pressure reducing solenoid valve is also well avoided.
As a result, it is possible to satisfactorily avoid the occurrence of a problem that the brake fluid containing bubbles is pumped up by the pump and supplied to the brake cylinder or the like.

Aspects of the Invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. 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 each of the following items, (1) corresponds to claim 1, (2) corresponds to claim 2, and (7) corresponds to claim 3.

(1) a reservoir in which the internal pressure is maintained at substantially atmospheric pressure and the brake fluid is stored;
A pump that pumps brake fluid directly from the reservoir through the suction passage and supplies it to the brake cylinder;
Brake fluid pressure provided in a return passage connecting the brake cylinder to the suction passage, and a pressure reducing solenoid valve that allows the brake fluid to flow out from the brake cylinder to the reservoir and reduces the fluid pressure of the brake cylinder A control device,
Brake fluid pressure control including a suction negative pressure transmission suppressing device that allows the brake fluid to flow from the pressure reducing solenoid valve to the suction passage and suppresses the suction negative pressure of the pump to the pressure reducing solenoid valve. apparatus.
(2) The suction negative pressure transmission suppressing device is provided in a portion of the return passage between the connection portion to the suction passage and the pressure reducing solenoid valve, and the pressure reducing solenoid valve is a hydraulic pressure of the brake cylinder. Is opened to allow communication between the pressure reducing solenoid valve and the suction passage, and when the pressure reducing solenoid valve does not decrease the hydraulic pressure of the brake cylinder, it is closed to allow communication between the pressure reducing solenoid valve and the suction passage. The brake hydraulic pressure control device according to item (1), including a suction negative pressure transmission cutoff device that shuts off the transmission of the suction negative pressure of the pump to the pressure reducing solenoid valve.
As in the brake hydraulic pressure control device described in the next section, the suction negative pressure transmission cutoff device may be configured by a pressure reducing valve that opens and closes based on a hydraulic pressure difference between the front and rear, or may be configured by an electromagnetic on-off valve. In the case of the electromagnetic open / close valve, it is desirable that the electromagnetic open / close valve is controlled in synchronization with the pressure reducing electromagnetic valve so that both can be opened and closed together.
When the solenoid valve for pressure reduction is opened, the suction negative pressure transmission cutoff device is also opened, and the brake fluid flows out of the brake cylinder, and the brake cylinder pressure is reduced. The suction negative pressure transmission cutoff device is closed when the pressure reducing solenoid valve is closed and does not decrease the brake cylinder pressure. Even if suction negative pressure is generated by the operation of the pump, the suction negative pressure is reduced. Is not communicated to. Therefore, when the pressure reducing solenoid valve is opened while the pump is operating, the portion immediately downstream of the pressure reducing solenoid valve is not negative pressure, and bubbles generated due to the pressure drop are not dissolved in the brake fluid. It is avoided that it remains.
In addition, the suction negative pressure transmission cutoff device is provided in a portion between the return passage connecting to the suction passage and the pressure reducing solenoid valve, and the brake fluid pressure passing through the suction negative pressure transmission cutoff device is reduced. It is not as high as the brake fluid that passes through the solenoid valve, and bubbles are not generated due to a pressure drop downstream of the suction negative pressure transmission cutoff device. Therefore, the suction negative pressure is transmitted to the suction negative pressure transmission cutoff device, but the brake fluid can flow to the suction passage without causing a situation in which bubbles remain in the brake fluid.
(3) The suction negative pressure transmission shut-off device is closed while a hydraulic pressure difference between the pressure reducing electromagnetic valve side and the suction passage side is equal to or lower than a set valve opening pressure, and the liquid on the pressure reducing electromagnetic valve side is closed. In a state where the pressure is higher than the set valve opening pressure than the fluid pressure on the suction passage side, the brake fluid flows from the pressure reducing solenoid valve to the suction passage by being opened by a differential pressure acting force based on the difference between the fluid pressures. The brake fluid pressure control device according to item (2), including a pressure reducing valve that allows
The pressure reducing valve in this section is mechanically opened and closed based on the hydraulic pressure difference before and after it, and is inexpensive, but ensures that the pressure on the pressure reducing solenoid valve side is higher than the pump opening pressure. Can do.
(4) The pressure reducing valve is
With bento,
A valve seat,
The valve element is urged in the direction of seating on the valve seat, and the urging force is higher than the set valve opening pressure in which the hydraulic pressure on the pressure reducing solenoid valve side is higher than the hydraulic pressure on the suction passage side. The brake hydraulic pressure control device according to (3), wherein the brake hydraulic pressure control device is a seat valve provided with an urging means sized to allow the valve element to be separated from the valve seat in a state.
In this brake fluid pressure control device, the set valve opening pressure is set by selecting the urging force of the urging means. Even if the pump is operated and negative suction pressure is generated, the set valve opening pressure does not cause the valve element to be separated from the valve seat due to the negative pressure, and can be kept in a seated state on the valve seat. Then, it is set to a magnitude that can sufficiently reduce the brake cylinder pressure. Since the suction negative pressure is blocked by the pressure reducing valve having a very small pressure reducing amount, a check valve in which the valve element is biased toward the valve seat by the spring can be used in many cases.
(5) including a brake fluid outflow allowing passage when the pressure reducing valve is closed, which allows a brake fluid to flow at a flow rate equal to or less than ½ of the flow rate when the pressure reducing valve is open. ) Or the brake fluid pressure control device according to item (4).
When the pressure reducing valve is closed, the flow rate of the brake fluid allowed to flow is preferably less than or equal to 1/2 of the flow rate of the brake fluid when the pressure reducing valve is open, and is 1/3. It is further desirable that it is / 4 and 1/5.
According to the brake fluid pressure control device of this section, for example, when the brake operation is finished and the brake fluid in the brake cylinder is returned to the reservoir through the pressure reducing solenoid valve, the residual pressure in the brake cylinder is set to open the pressure reducing valve. The pressure can be made smaller than the valve pressure, and in some cases, the residual pressure can be made zero. The pressure reducing valve closes when the hydraulic pressure difference between the pressure on the pressure reducing solenoid valve and the pressure on the suction passage falls below the set valve opening pressure, but brake fluid is allowed to flow out when the pressure reducing valve is closed. This is because it is possible to return from the brake cylinder to the reservoir through the passage. The brake fluid flow allowing passage when the pressure reducing valve is closed allows a small amount of brake fluid, and the negative suction pressure when the pump is operated is prevented from being transmitted to the pressure reducing electromagnetic valve through this passage. From this point of view, it is desirable that the flow rate of the brake fluid outflow allowable passage when the pressure reducing valve is closed is small, but it is desirable that the flow rate be large in order to reduce the residual pressure of the brake cylinder. It is.
(6) The pressure reducing valve is
With bento,
A valve seat,
The valve element is urged in the direction of seating on the valve seat, and the urging force is higher than the set valve opening pressure in which the hydraulic pressure on the pressure reducing solenoid valve side is higher than the hydraulic pressure on the suction passage side. And a biasing means for biasing the valve element in a direction that allows the valve element to be separated from the valve seat, and the brake fluid outflow passage when the pressure reducing valve is closed is formed in the valve seat, Even in a state where the valve element is seated on the valve seat, a part on the pressure reducing solenoid valve side and a part on the suction passage side are communicated with each other from the pressure reducing valve of the return passage. The brake fluid pressure control device according to item (5), including a recess that forms a communication path to be maintained.
A bypass passage that bypasses the pressure reducing valve may be provided in the return passage, and a throttle may be provided in the bypass passage to provide a brake fluid outflow allowing passage when the pressure reducing valve is closed. However, if a recess is provided in the valve seat as in this section, the brake fluid outflow passage when the pressure reducing valve is closed can be easily formed.
(7) The suction negative pressure transmission suppression device includes a suction negative pressure generation suppression device that suppresses the generation of suction negative pressure in the pump while always allowing communication between the suction passage and the pressure reducing solenoid valve. The brake fluid pressure control device according to item 1).
In the brake fluid pressure control device of this section, since the generation of the suction negative pressure itself is suppressed, the suction negative pressure is not transmitted to the pressure reducing solenoid valve or is small. Therefore, communication between the suction passage and the pressure reducing electromagnetic valve can be always allowed. Further, by suppressing the generation of the suction negative pressure, the vibration of the suction passage and the like and the pump operation noise due to the suction pulsation are suppressed.
(8) The suction negative pressure generation suppressing device is connected near the suction port of the pump, supplies brake fluid to the suction port when the pump is sucked, and brake fluid from the suction passage side when the pump is not sucked. The brake fluid pressure control device according to item (7), including a damper that suppresses the generation of negative pressure at the suction port by allowing the inflow of.
Here, “near” means that the distance from the suction port is preferably in the range of 100 mm or less, more preferably in the range of 50 mm or less, and further preferably in the range of 30 mm or less.
The damper may be provided in the return passage or in the suction passage as long as it is in the vicinity of the suction port.
Even if there is resistance against pumping of brake fluid from the reservoir by the pump, the supply of brake fluid from the damper suppresses the generation of suction negative pressure, and inconvenience occurs due to the transmission of the suction negative pressure to the pressure reducing solenoid valve. Good avoidance. Since the damper is provided in the vicinity of the suction port, the brake fluid is quickly supplied to the suction port, and the generation of the suction negative pressure is well suppressed. The brake fluid supplied from the damper is returned to the damper by supplying brake fluid from the reservoir when not inhaling, for example, when discharging or stopping the pump operation.
(9) The brake hydraulic pressure control device according to (8), wherein the damper has an internal volume that increases or decreases with elastic deformation of the film-like elastic member.
The film-like elastic member may be constituted by, for example, a thin metal plate, or may be constituted by rubber or the like.
(10) The brake fluid pressure control device according to (8), wherein the damper is a chamber that houses brake fluid in a lower portion, accommodates atmospheric gas in an upper portion, and communicates with the suction port in the lower portion.
By supplying brake fluid from the chamber to the suction passage, the generation of suction negative pressure is satisfactorily suppressed. It is desirable that the chamber be blocked from communicating with the outside so that dust or the like does not enter. In that case, even if the volume of the brake fluid stored in the chamber increases or decreases due to the inflow or outflow of the brake fluid between the chamber and the suction passage, the pressure of the gas stored in the upper portion is maintained at atmospheric pressure. It is desirable to avoid the reduction of the suction negative pressure suppression effect due to the change in gas pressure.

  Several embodiments of the claimable invention will now be described in detail with reference to the drawings.

<First Example>
FIG. 1 conceptually shows a hydraulic brake system including a brake hydraulic pressure control device 10 according to an embodiment of the present invention. The brake fluid pressure control device 10 includes a brake operation device 12 for performing a brake operation by a driver, and a hydraulic pressure in a brake cylinder 14 of a brake provided on each of four wheels based on the brake operation. And a brake actuator 16 to be controlled. In FIG. 1, FL represents a left front wheel, FR represents a right front wheel, RL represents a left rear wheel, and RR represents a right rear wheel.

  The brake operation device 12 includes a brake pedal 20 and a master cylinder 22 as brake operation members rotatably provided on a vehicle body not shown. In the brake fluid pressure control device 10, fluid pressure is generated in the two pressurizing chambers of the master cylinder 22 based on the depression of the brake pedal 20, and the brake cylinders 14 of the left and right front wheels are based on the fluid pressures. Is activated. One of the two pressurizing chambers of the master cylinder 22 is also connected to the stroke simulator 28 via the on-off valve 26.

  The brake operating device 12 is further provided with a reservoir 30 for storing brake fluid together with the master cylinder 22. The reservoir 30 has a container shape, and its opening is closed by a cap that can be attached and removed, and stores brake fluid. The reservoir 30 is communicated with each of the two pressurization chambers of the master cylinder 22 in a state where the brake pedal 20 is not operated. When the brake pedal 20 is depressed, the communication with each of the two pressurization chambers is blocked. The hydraulic pressure is allowed to be generated in these pressurizing chambers. For example, the reservoir 30 is provided with a pressure adjusting device such as a relief valve in a cap that closes the opening thereof, so that the internal pressure of the reservoir 30 is maintained at substantially atmospheric pressure.

  As shown in FIG. 1, the brake actuator 16 includes two master cut valves 38, a hydraulic pressure source device 40, four pressure increasing solenoid valves 42 and four pressure reducing solenoid valves 44, and two master cylinder pressure sensors 46 and 4. Two brake cylinder pressure sensors 48 are provided. These components of the brake actuator 16 are integrally assembled to a box-shaped main body member (not shown). The brake actuator 16 is provided between the master cylinder 22, the four brake cylinders 14, and the reservoir 30, and the master cylinder passage 52 is used to connect the master cylinder 22 to the two master cylinder connection ports 50 provided in the main body member. Connected to the two pressurizing chambers, respectively, connected to the four brake cylinders 14 via the brake cylinder passage 56 at the four brake cylinder connection ports 54, and connected to the reservoir 30 via the reservoir passage 60 at the reservoir connection port 58. .

  Each of the two master cylinder connection ports 50 is connected to a brake cylinder connection port 54 connected to the brake cylinder 14 of each brake of the left and right front wheels by a liquid passage 64 in the main body member. A valve 38 is provided. The hydraulic pressure source device 40 includes a pump 70 that pumps brake fluid from the reservoir 30, an accumulator 72 that stores the brake fluid discharged from the pump 70 under pressure, and a relief valve for appropriately maintaining the hydraulic pressure in the accumulator 72. 74, and the brake fluid is supplied to the brake cylinder 14 at a constant pressure. The pump 70 is connected to the reservoir 30 by a suction passage 76, a reservoir connection port 58 and a reservoir passage 60 provided in the main body member. The pump 70 is driven by a motor 80 as a driving source, and is connected to the brake cylinder 14 together with the accumulator 72. The pump 70 is operated when the pressure of the accumulator 72 detected by the accumulator pressure sensor 82 becomes a set value or less. The brake fluid is pumped up from the reservoir 30 through the reservoir passage 60 and the suction passage 76, sucked from the suction port 84 and discharged from the discharge port 86, and the brake fluid is stored in the accumulator 72 under pressure. The hydraulic pressure source device 40 is a power hydraulic pressure source that generates hydraulic pressure by power. If the hydraulic pressure in the accumulator 72 exceeds the relief pressure, the relief valve 74 opens and the brake fluid is discharged from the accumulator 72 toward the reservoir 30, and the accumulator pressure that is the hydraulic pressure of the accumulator 72 is maintained at an appropriate height. The Between the pump 70 and the reservoir 30, there are no components other than a member for forming a suction passage (a suction passage including the reservoir passage 60 and the suction passage 76) such as a rubber hose, a pipe, and a joint member. The suction port 84 and the reservoir 30 are always in communication, and the brake fluid does not pass through the valve or the like until the brake fluid is sucked into the pump 70 from the reservoir 30. The brake fluid is pumped up through the suction passage 76. As will be described later, the return passage is connected to the suction passage 76, but the brake fluid that is outside the suction passage 76 and pumped up by the pump 70 from the reservoir 30 does not pass through a part of the return passage.

  In the present embodiment, each of the four pressure increasing solenoid valves 42 and the pressure reducing solenoid valves 44 is a linear solenoid valve, and the pressure increasing solenoid valve 42 increases the accumulator pressure by controlling the supply current. The pressure is controlled to an appropriate height and supplied to the brake cylinder 14 to increase the brake cylinder pressure. The pressure reducing solenoid valve 44 allows the brake fluid to flow from the brake cylinder 14 to the reservoir 30 to increase the brake cylinder pressure. Decrease. The four pressure-increasing solenoid valves 42 are all normally closed valves in this embodiment, and two of them are between the master cut valve 38 and the brake cylinder connection port 54 of the two fluid passages 64. A brake cylinder connection port 54 connected to the brake cylinder 14 of the left and right rear wheel brakes is provided in each of two power pressure passages or pressure-increasing passages 94 connecting the portion and the hydraulic pressure source device 40. Are provided in two power pressure passages or pressure-increasing passages 96 connecting the fluid pressure source device 40 and the fluid pressure source device 40, respectively.

  The four brake cylinder connection ports 54 also include each of the pressure increase solenoid valves 42 of the pressure increase passages 94 and 96 (including part of the fluid passage 64 for the pressure increase passage 94) and four brake cylinder connection ports. 54 is connected to the suction passage 76 by a return passage 98 connected to a portion between them and a return passage 100 to which the four return passages 98 are connected. Each of the four brake cylinders 14 is a part of each of the brake cylinder passage 56 and the pressure increasing passages 94 and 96 (or a part of the fluid passage 64 for the brake cylinder 14 to which hydraulic pressure is supplied by the pressure increasing passage 94) The return passage including the passages 98 and 100 is connected to the suction passage 76, and further connected to the reservoir 30 by the reservoir passage 60. The suction passage 76 and the reservoir passage 60 that is also the suction passage include the pump 70 and the reservoir 30. And a part of the suction passage 76 and the reservoir passage 60 also serve as a return passage that allows the brake fluid to return from the brake cylinder 14 to the reservoir 30. The four pressure reducing solenoid valves 44 are provided in each of the four return passages 98 that connect the brake cylinder 14 to the suction passage 76, and allow the brake fluid to flow from the brake cylinder 14 to the reservoir 30. Reduce fluid pressure.

  A return passage constituted by the return passages 98 and 100 is a portion between the connection portion to the suction passage 76 and the pressure reducing electromagnetic valve 44, and the pressure reducing valve 110 is provided in the return passage 100. In this embodiment, the pressure reducing valve 110 is a seat valve as shown in FIG. 2, and includes a casing 112, a valve element 114, a valve seat member 116, and a spring 118 as an elastic member which is a kind of biasing means. Including. The valve seat member 116 is provided with a passage 120 passing through the inside thereof, and a valve seat 122 is provided at the opening end of the passage 120 on the suction passage 76 side. The spring 118 is held by the casing 112 and urges the ball-shaped valve element 114 to be seated on the valve seat 122 against the hydraulic pressure of the return passage 100 on the pressure reducing electromagnetic valve 44 side.

  The pressure reducing valve 110 is closed while the hydraulic pressure difference between the pressure reducing electromagnetic valve 44 side and the suction passage 76 side is equal to or lower than the set valve opening pressure, and the communication between the pressure reducing electromagnetic valve 44 and the suction passage 76 is cut off. In a state where the hydraulic pressure on the pressure reducing solenoid valve 44 side is higher than the hydraulic pressure on the suction passage 76 side and exceeds the set valve opening pressure, the pressure is reduced by the differential pressure acting force based on the difference between the hydraulic pressures. The brake fluid is allowed to flow from the electromagnetic valve 44 to the suction passage 76. The pressure reducing valve 110 is opened when the valve element 114 moves away from the valve seat 122 against the urging force of the spring 118, and the urging force of the spring 118 is such that the hydraulic pressure on the pressure reducing electromagnetic valve 44 side is the suction passage 76. The valve element 114 has a size that allows the valve element 114 to be separated from the valve seat 122 in a state in which the set valve opening pressure is higher than the hydraulic pressure on the side. The set valve opening pressure is set by selecting the urging force of the spring 118. In this embodiment, as will be described later, even if the pump 70 is operated and suction negative pressure is generated, the valve element 114 is caused by the negative pressure. Is set to such a size that it can be kept seated on the valve seat 122 without being separated from the valve seat 122 and can sufficiently reduce the brake cylinder pressure. The pressure reducing valve 110 is a pressure reducing valve with a very small amount of pressure reduction, and a check valve is used in this embodiment. In FIG. 2, reference numeral 126 denotes an opening, which is provided in a plurality in the casing 112, and the brake fluid that flows in from the pressure reducing electromagnetic valve 44 side flows through the opening 126 to the suction passage 76 side.

  The valve seat 122 is formed with a plurality of grooves 128 as recesses. The groove 128 is provided through the valve seat 122 in the direction in which the brake fluid flows, and the pressure reducing valve 110 of the return passage 100 is located between the valve disc 114 and the valve disc 114 even when the valve disc 114 is seated on the valve seat 122. Further, a portion on the pressure reducing electromagnetic valve 44 side and a portion on the suction passage 76 side are provided so as to be in communication with each other to form a communication passage. In this embodiment, the cross-sectional area of the groove 128 is the sum of the flow rates of the brake fluid allowed by the plurality of grooves 128 when the pressure reducing valve 110 is closed, and 1 of the flow rate of the brake fluid when the pressure reducing valve 110 is open. The flow rate is set to / 5.

  In the brake fluid pressure control device 10 configured as described above, the brake actuator 16 is normally operated based on the depression of the brake pedal 20, and the brake cylinder pressure is controlled. At this time, the two master cut valves 38 are both closed, the communication between the master cylinder 22 and the brake cylinder 14 is shut off, and the on-off valve 26 is opened to allow the master cylinder 22 to communicate with the stroke simulator 28. Thus, a feeling of operation is given to the driver. On the other hand, in the brake actuator 16, opening and closing of the pressure-increasing solenoid valve 42 and the pressure-reducing solenoid valve 44 by a computer (not shown) based on the amount of operation of the brake pedal 20 by the driver, wheel speed, vehicle body speed, brake cylinder pressure, and the like. Control is performed, and braking control of the vehicle is performed by increasing or decreasing the hydraulic pressure in each brake cylinder 14.

  When increasing the brake cylinder pressure, the hydraulic pressure generated by the hydraulic pressure source device 40 is supplied to the four brake cylinders 14 via the pressure increase passages 94 and 96 and the brake cylinder passage 56. This hydraulic pressure is controlled to an appropriate height by the pressure increasing electromagnetic valve 42, and each of the four wheel brakes is operated. Further, when the brake cylinder pressure is maintained, the pressure increasing electromagnetic valve 42 is closed. In this way, when the brake cylinder pressure is increased and maintained and when the brake cylinder pressure is not decreased, the pressure reducing solenoid valve 44 is closed, the pressure reducing valve 110 is closed, and the pressure reducing electromagnetic valve 44 and the suction passage are closed. Block communication with 76. When the brake cylinder pressure is decreased, the pressure reducing solenoid valve 44 is opened, and the pressure reducing valve 110 is configured such that the hydraulic pressure on the pressure reducing solenoid valve 44 side exceeds the set valve opening pressure than the hydraulic pressure on the suction passage 76 side. In a high state, the valve opens and permits communication between the pressure reducing solenoid valve 44 and the suction passage 76, the brake fluid flows out of the brake cylinder 14, returns to the reservoir 30 through the return passages 98, 100, etc., and the brake cylinder pressure is increased. Reduced.

  In order to increase the brake cylinder pressure, the brake fluid is supplied from the accumulator 72 to the brake cylinder 14, and when the accumulator pressure becomes lower than the set value, the pump 70 is operated, and from the reservoir 30 through the reservoir passage 60 and the suction passage 76. The brake fluid is pumped up and stored in the accumulator 72 under pressure. Since the return passage 100 is connected to the suction passage 76, when the pump 70 pumps up the brake fluid from the reservoir 30, suction negative pressure is generated and transmitted to the return passage 100. Although the internal pressure of the reservoir 30 is maintained at almost atmospheric pressure, the reservoir 30 is separated from the brake actuator 16, and the brake from the reservoir 30 is caused by the inertia of the brake fluid itself and the flow path resistance of the suction passage 76. A delay occurs in the pumping of the liquid, and negative suction pressure is generated and transmitted to the return passage 100 connected to the suction passage 76. However, since the pressure reducing valve 110 is provided in the return passage 100 and is closed except when the brake cylinder pressure is reduced, the suction negative pressure is not transmitted to the pressure reducing electromagnetic valve 44 and the pump is in operation. Even if the pressure reducing solenoid valve 44 is opened, the generated bubbles do not remain in the brake fluid without being dissolved.

  When the pressure reducing solenoid valve 44 is opened, the hydraulic pressure on the brake cylinder 14 side is higher than the pressure pressure on the pressure reducing valve 110 and suction passage 76 side than the pressure reducing solenoid valve 44 in the return passages 98 and 100. The flow rate of the brake fluid in the vicinity of the valve element 114 of the valve 44 is increased, the pressure is locally reduced, cavitation occurs, and aeration in which air dissolved by several percent in the brake fluid becomes bubbles is generated. At this time, if the portion immediately downstream of the pressure reducing solenoid valve 44 is a negative pressure due to the transmission of the suction negative pressure of the pump 70, the bubbles generated when the pressure reducing solenoid valve 44 is opened are in the brake fluid. It will not melt and will remain. However, when the pressure reducing solenoid valve 44 is closed, the pressure reducing valve 110 is closed, the communication between the pressure reducing solenoid valve 44 and the suction passage 76 is cut off, and the pressure reducing solenoid valve for suction negative pressure by the pump operation is cut off. Even if the pressure reducing solenoid valve 44 is opened during the pump operation, the hydraulic pressure in the portion immediately downstream of the pressure reducing solenoid valve 44 is maintained at or above atmospheric pressure, or the atmospheric pressure is reduced. Even lower, very little. Therefore, the generated bubbles can immediately dissolve into the brake fluid and do not remain. The portion of the return passage 100 closer to the pressure reducing solenoid valve 44 than the pressure reducing valve 110 and the portion closer to the suction passage 76 are communicated by the groove 128 even when the pressure reducing valve 110 is closed. Is 1/5 of the flow rate of the brake fluid in the open state, and the suction negative pressure is not transmitted to the pressure reducing electromagnetic valve 44 through the groove 128. The pressure reducing valve 110 is provided at a portion between the connection portion of the return passage 100 to the suction passage 76 and the pressure reducing electromagnetic valve 44, and the pressure of the brake fluid passing through the pressure reducing valve 110 is reduced. 44 is not as high as the brake fluid passing through 44, and bubbles are not generated due to a pressure drop downstream of the pressure reducing valve 110. Therefore, the suction negative pressure is transmitted to the pressure reducing valve 110, but the brake fluid can flow to the suction passage 76 without causing a situation in which bubbles remain in the brake fluid.

  When the depression of the brake pedal 20 is released, the current supply to the pressure increasing solenoid valve 42 and the pressure reducing solenoid valve 44 is cut off. Therefore, the normally closed pressure increasing electromagnetic valve 42 is closed, and among the pressure reducing electromagnetic valves 44, the normally closed pressure reducing electromagnetic valve 44 is closed, and the normally open pressure reducing electromagnetic valve 44 is opened. Since the brake cylinder 14 provided with the normally closed pressure reducing solenoid valve 44 is connected to the master cylinder 22, the brake cylinder 14 passes through the master cut valve 38 that is opened when the current supply is cut off. The brake fluid returns to the master cylinder 22. The brake cylinder 14 provided with the normally open pressure reducing solenoid valve 44 is not connected to the master cylinder 22, and the brake fluid in the brake cylinder 14 is returned to the return passages 98, 100, and the pressure reducing solenoid valve is open. 44 and the groove 128 of the pressure reducing valve 110, the suction passage 76, and the reservoir passage 60 to return to the reservoir 30. In the pressure reducing valve 110, when the hydraulic pressure difference between the pressure reducing electromagnetic valve 44 side and the suction passage 76 side becomes equal to or less than the set valve opening pressure, the valve element 114 is seated on the valve seat 122 and closed by the bias of the spring 118. However, the plurality of grooves 128 keeps the portion of the return passage 100 closer to the pressure reducing electromagnetic valve 44 than the pressure reducing valve 110 and the portion closer to the suction passage 76, and the brake in the state where the pressure reducing valve 110 is open. The flow of the brake fluid at a flow rate that is 1/5 of the fluid flow rate is allowed, the brake fluid in the brake cylinder 14 can return to the reservoir 30, and the residual pressure in the brake cylinder 14 can be zero. .

<Second Example>
Another embodiment of the claimable invention will be described with reference to FIG.
In this brake hydraulic pressure control device 150, as shown in FIG. 3, a damper 160 constituting a suction negative pressure generation suppressing device is provided instead of the pressure reducing valve 110 as a suction negative pressure transmission cutoff device. In this embodiment, the damper 160 includes two metal thin discs 162 and the peripheral portions thereof are fixed to each other. The liquid chamber 164 formed by the discs 162 includes the suction passage 76 and the pressure reducing electromagnetic wave. It is connected to the return passage 100 in a state where communication with the valve 44 is always allowed. Each of the two discs 162 is provided with concavities and convexities in a concentric manner so that the cross-sectional shape in the axial direction is corrugated and can be elastically deformed to constitute a film-like elastic member. The damper 160 is provided in the vicinity of the suction port 84 of the pump 70, and in the present embodiment, in the vicinity of the connection portion of the return passage 100 to the suction passage 76 and at a distance from the suction port 84 of 50 mm. It has been. If possible, the damper 160 is preferably housed in a recess provided in the body member of the brake actuator 16, for example. Alternatively, the damper 160 may be housed in a protective case and attached to the body member.

  When the pump 70 is operated, the generation of the suction negative pressure is suppressed by the damper 160. The internal volume of the fluid chamber 164 of the damper 160 increases and decreases with the elastic deformation of the disc 162, supplying brake fluid to the suction port 84 when the pump 70 is inhaled, and braking from the suction passage 76 side when the pump 70 is not inhaled. Allow inflow of liquid. If there is a delay in pumping the brake fluid from the reservoir 30, the brake fluid is supplied from the damper 160, and the generation of negative pressure at the suction port 84 is suppressed. The amount of brake fluid supplied from the damper 160 is returned to the damper 160 by supplying brake fluid from the reservoir 30 when the pump 70 is not inhaled, for example, when discharging or stopping the pump operation. Due to the suppression of the generation of the suction negative pressure by the damper 160, the pressure reducing electromagnetic valve 44 is always in communication with the suction passage 76, but the portion immediately downstream of the pressure reducing electromagnetic valve 44 is negative pressure during the operation of the pump 70. Even if the pressure reducing solenoid valve 44 is opened during the pump operation, bubbles generated due to a local pressure drop are not maintained. It immediately dissolves in the brake fluid and does not remain in the brake fluid.

<Third embodiment>
When a damper is provided as the suction negative pressure generation suppressing device, a chamber 180 may be provided as shown in FIG. The chamber 180 has a container shape in this embodiment, and is connected to the vicinity of the suction port 84 of the pump 70 of the return passage 100 by, for example, a portion 50 mm away from the suction port 84 by the passage 182. The chamber 180 is provided at a position including the position of the level of the brake fluid stored in the reservoir 30 in the vertical direction, the brake fluid is stored in the lower portion, the atmospheric pressure gas such as air is stored in the upper portion, and the lower portion , The return passage 100 is connected in a state allowing the suction passage 76 and the pressure reducing electromagnetic valve 44 to communicate with each other, and is connected to the suction port 84.

  The opening of the chamber 180 is covered with a lid 190 to block communication with the outside, and entry of dust and the like is prevented. In this embodiment, the lid 190 is made of rubber, which is a kind of elastic member, and has a corrugated shape. The chamber 180 supplies the brake fluid to the suction port 84 when the brake fluid is sucked by the pump 70, allows the brake fluid to flow in from the suction passage 76 when not sucked, and suppresses the generation of the suction negative pressure. Even if the volume of the brake fluid stored in the lower portion of the chamber 180 increases or decreases due to the inflow or outflow of the brake fluid, the pressure of the air stored in the upper portion is maintained at the atmospheric pressure due to the elastic deformation of the lid 190. The elastically deformable lid 190 is also a pressure adjusting device, and it is avoided that the effect of suppressing the suction negative pressure is reduced due to a change in air pressure.

  The damper is provided with a single membrane elastic member in the casing, a liquid chamber provided on one side of the membrane elastic member is connected to the suction passage, and a gas chamber provided on the other side is connected to the atmosphere. It is good also as what makes it communicate. The gas chamber may be omitted, and the film-like elastic member may be directly exposed to the atmosphere.

  Further, the pressure reducing solenoid valve is not limited to a linear solenoid valve, and may be constituted by, for example, an electromagnetic on-off valve or a part of an electromagnetic direction switching valve. The same applies to the solenoid valve for pressure increase.

  Further, it is not indispensable to form a plurality of pressure increasing solenoid valves and pressure reducing solenoid valves or the like integrally with the main body member to constitute a brake actuator, but they may be provided separately.

  Further, in the hydraulic brake system including the brake hydraulic pressure control device of each of the above embodiments, a part of the four wheels, for example, the brake cylinder of each brake of the left and right front wheels, is generated in the pressurizing chamber of the master cylinder. And the hydraulic pressure obtained by the hydraulic pressure source device of the brake actuator is selectively supplied, and another part, for example, the brake cylinder of each brake of the left and right rear wheels, Although only the hydraulic pressure obtained by the pressure source device is supplied, two types of hydraulic pressures may be selectively supplied to all four wheels. At this time, the two hydraulic pressures respectively generated in the two pressurizing chambers of the master cylinder are supplied to the brake cylinders of the brakes of the four wheels in various modes. For example, it is supplied to the left and right front wheel system and the left and right rear wheel system, or is supplied to the left front wheel-right rear wheel system and the right front wheel-left rear wheel system.

  Further, the brake fluid pressure control device of each of the above embodiments includes a master cylinder, and the fluid pressure generated in the pressurizing chamber of the master cylinder and the fluid pressure supplied from the fluid pressure source device of the brake actuator are selected. However, it is not indispensable to include a brake operating device, although the brake is supplied to the brake cylinder and activated. For example, when using a brake to perform traction control or vehicle stability control that maintains vehicle running stability, the brake hydraulic pressure control device is used as a brake operation device. It is comprised without including. Even when the brake is operated based on an operation by the driver, it can be considered that the brake fluid pressure control device is configured without including the brake operation device.

  Although several embodiments of the claimable invention have been described in detail above, these are merely examples, and the claimable invention includes the aspects described in the above [Aspect of the Invention]. The present invention can be implemented in various forms based on the knowledge of the trader.

1 is a circuit diagram showing a hydraulic brake system including a brake hydraulic pressure control device according to an embodiment of the claimable invention. FIG. It is front sectional drawing which shows the pressure-reduction valve provided in the brake actuator of the said brake fluid pressure control apparatus. It is a circuit diagram which shows the hydraulic brake system containing the brake hydraulic pressure control apparatus which is another Example of this claimable invention. It is a figure which shows the chamber of the brake fluid pressure control apparatus which is another Example of this invention which can be claimed.

Explanation of symbols

  10: Brake hydraulic pressure control device 14: Brake cylinder 16: Brake actuator 30: Reservoir 44: Pressure reducing solenoid valve 60: Reservoir passage 70: Pump 76: Suction passage 100: Return passage 110: Pressure reducing valve 114: Valve element 118: Spring 122: Valve seat 128: Groove 150: Brake hydraulic pressure control device 160: Damper 180: Chamber

Claims (3)

The internal pressure is kept at almost atmospheric pressure and the reservoir for storing brake fluid;
A pump that pumps brake fluid directly from the reservoir through the suction passage and supplies it to the brake cylinder;
Brake fluid pressure provided in a return passage connecting the brake cylinder to the suction passage, and a pressure reducing solenoid valve that allows the brake fluid to flow out from the brake cylinder to the reservoir and reduces the fluid pressure of the brake cylinder A control device,
A suction negative pressure transmission suppressing device that allows a brake fluid to flow from the pressure reducing solenoid valve to the suction passage and that suppresses transmission of suction negative pressure of the pump to the pressure reducing solenoid valve; Brake fluid pressure control device.   The suction negative pressure transmission suppressing device is provided at a portion of the return passage between the connection portion to the suction passage and the pressure reducing solenoid valve, and the pressure reducing solenoid valve reduces the hydraulic pressure of the brake cylinder. Open in a state to allow communication between the pressure reducing solenoid valve and the suction passage, and close in a state where the pressure reducing solenoid valve does not decrease the hydraulic pressure of the brake cylinder to block communication between the pressure reducing solenoid valve and the suction passage. The brake hydraulic pressure control device according to claim 1, further comprising: a suction negative pressure transmission blocking device that blocks transmission of the suction negative pressure of the pump to the pressure reducing solenoid valve.   The suction negative pressure transmission suppressing device includes a suction negative pressure generation suppressing device that suppresses generation of suction negative pressure in the pump while always allowing communication between the suction passage and the pressure reducing solenoid valve. The brake fluid pressure control device according to claim 1.

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