US20130088076A1 - Automotive Hydraulic Brake System - Google Patents
Automotive Hydraulic Brake System Download PDFInfo
- Publication number
- US20130088076A1 US20130088076A1 US13/687,303 US201213687303A US2013088076A1 US 20130088076 A1 US20130088076 A1 US 20130088076A1 US 201213687303 A US201213687303 A US 201213687303A US 2013088076 A1 US2013088076 A1 US 2013088076A1
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- Prior art keywords
- passage
- pressure
- valve
- master cylinder
- intake
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
- B60T13/16—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using pumps directly, i.e. without interposition of accumulators or reservoirs
- B60T13/161—Systems with master cylinder
- B60T13/167—In combination with distributor valve
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/341—Systems characterised by their valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
- B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
- B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
- B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
- B60T8/4872—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems
Abstract
An automotive hydraulic brake system is provided which exhibits an excellent pressure reduction performance to a low μ road while restraining an intake resistance of a fluid pump. For providing the hydraulic brake system, a gate-in valve is connected to an intake passage that connects a master cylinder to an intake side of the fluid pump. The gate-in valve selectively opens and closes the intake passage in accordance with a mutual relation between a master cylinder pressure and a pressure produced at an intake side of the fluid pump.
Description
- This application is a continuation of U.S. patent application Ser. No. 12/683,139, filed Jan. 6, 2010, the entire disclosure of which is incorporated herein by reference, the priority of which is claimed, which claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2009-072248, filed Mar. 24, 2009, the priority of which is also claimed here.
- 1. Field of the Invention
- The present invention relates in general to automotive hydraulic brake systems, and more particularly to the automotive hydraulic brake systems of a type that obtains a sufficient pressure reduction performance to a low μ road while restraining a fluid intake resistance of a brake fluid pump.
- 2. Description of the Related Art
- Before describing the automotive hydraulic brake system of the present invention, meaning of the low μ road and the pressure reducing performance will be explained. That is, the low μ road is a road of which surface has a low coefficient of friction and the pressure reduction performance is a performance in effectively reducing the brake fluid pressure for wheel cylinders of the hydraulic brake system, that is needed when the vehicle is braked without skid.
- One of the automotive brake systems of the above-mentioned type is described in Japanese Laid-open Patent Application (Tokkai) 2007-238095. In the automotive hydraulic brake system of the publication, there is employed an internal reservoir that temporarily reserves a brake fluid from wheel cylinders for adjusting a fluid pressure that is applied from a master cylinder to an intake port of a fluid pump. The internal reservoir shown by the publication comprises a larger main case, a smaller auxiliary case, an apertured valve seat portion through which the main and auxiliary cases are connected, a piston slidably disposed in the main case, a biasing spring installed in the main case to bias the piston toward the auxiliary case, a pin connected to the piston and extending to the auxiliary case through the apertured valve seat portion, a ball (or valve body) placed in the auxiliary case and contactable to a leading end of the pin to move therewith. An operation chamber of the main case is connected to an inlet port of a rotary pump and the auxiliary case is connected to a downstream side of a brake fluid circuit.
- For properly operating the hydraulic brake system of the publication against a higher master cylinder pressure, the biasing spring of the reservoir should be set to have a higher spring force or a size (or pressure receiving area) of the ball (or valve body) should be reduced. However, if the biasing spring is set to have a higher spring force, the pressure of the brake fluid from the wheel cylinders becomes higher, and thus, it is difficult to obtain a sufficient pressure reduction performance to a low μ road. While, if the size of the ball (or valve body) is small, a sufficient pressure reduction performance to the low μ road is obtainable. However, in this case, a fluid intake resistance of the brake fluid pump at the time when the brake fluid is sucked from the master cylinder side is increased and thus pressure boosting performance is lowered.
- Accordingly, an object of the present invention is to provide an automotive hydraulic brake system which is free of the above-mentioned drawbacks.
- According to the present invention, there is provided an automotive hydraulic brake system which obtains a sufficient pressure reduction performance to a low μ road while restraining a fluid intake resistance of a brake fluid pump.
- In the automotive hydraulic brake system of the present invention, a fluid intake passage extending from a master cylinder to a rotary fluid pump is equipped with a gate-in valve that is operated to selectively open and close the fluid intake passage in accordance with a pressure relation between a master cylinder pressure and an inlet pressure of the rotary fluid pump.
- In accordance with a first aspect of the present invention, there is provided a hydraulic brake system which comprises an intake passage connecting a master cylinder to an intake side of a fluid pump; a discharge passage connecting a discharge side of the fluid pump to the master cylinder; a first passage branched from the discharge passage and connected to a wheel cylinder; a pressure reduction passage connected to a reservoir that reserves a pressure reduced brake fluid from the wheel cylinder; an outlet passage connecting the reservoir to the intake passage; and a gate-in valve that selectively opens and closes the intake passage in accordance with both a master cylinder pressure produced by the master cylinder and a pump intake side pressure produced in an intake side of the fluid pump.
- In accordance with a second aspect of the present invention, there is provided a hydraulic brake system which comprises a fluid pump driven by an electric motor; and a housing that houses therein the fluid pump, wherein the housing comprises a master cylinder port to be connected to a master cylinder that is arranged outside the housing; an intake passage connecting the master cylinder port to an intake side of the fluid pump; a discharge passage connecting a discharge side of the fluid pump to the master cylinder port; a first passage branched from the discharge passage; a wheel cylinder port connecting the first passage to a wheel cylinder that is arranged outside of the housing; a pressure reduction passage through which a brake fluid in the wheel cylinder is led into a reservoir through the wheel cylinder port; and an outlet passage connecting the reservoir to the intake passage, and wherein the intake passage is provided with a pressure valve that selectively opens and closes the intake passage in accordance with a pressure difference between pressures respectively appearing at upstream and downstream portions of the intake passage with respect to the pressure valve.
- In accordance with a third aspect of the present invention, there is provided a hydraulic brake system which comprises a housing housing therein a fluid pump; an intake passage connecting an outside portion of the housing to an intake side of the fluid pump; a discharge passage connecting a discharge side of the fluid pump to the outside portion of the housing; a first passage branched from the discharge passage and connected to a wheel cylinder that is positioned outside the housing; a pressure reduction passage through which a brake fluid in the wheel cylinder is led into a reservoir; an outlet passage connecting the reservoir to the intake passage; and a gate-in valve provided by the intake passage, the gate-in valve selectively opening and closing the intake passage in accordance with a pressure difference between pressures respectively appearing at upstream and downstream portions of the intake passage with respect to the gate-in valve, wherein the fluid pump is arranged to suck the brake fluid through the gate-in valve from the outside portion of the housing.
- Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:
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FIG. 1 is a schematic view of a hydraulic circuit of an automotive hydraulic brake system of a first embodiment of the present invention; -
FIGS. 2A and 2B are sectional views of a gate-in valve employed in the first embodiment,FIG. 2A showing an open condition of the valve andFIG. 2B showing a closed condition of the same; -
FIGS. 3A and 3B are sectional views of a known internal valve disclosed in the above-mentioned publication,FIG. 3A showing an open condition of the valve andFIG. 3B showing a closed condition of the same; -
FIG. 4 is a graph showing a relationship between a hydraulic pressure and a spring force; -
FIG. 5 is a time chart showing a pump up operation of the hydraulic brake system of the first embodiment; -
FIG. 6 is a view similar toFIG. 1 , but showing a second embodiment of the present invention; and -
FIG. 7 is a view similar toFIG. 1 , but showing a third embodiment of the present invention. - In the following,
embodiments - In the following, for ease of understanding, various directional terms, such as, right, left, upper, lower, rightward and the like are used in the direction. However, such terms are to be understood with respect to only a drawing or drawings on which the corresponding part or portion is shown.
- First, a hydraulic brake system of a
first embodiment 100 will be described with the aid ofFIGS. 1 to 5 . - As will become apparent as the description proceeds, the hydraulic brake system of the
first embodiment 100 is of a mechanical & electric part integral type which generally comprises a master cylinder M/C, wheel cylinders W/C, an electric motor, hydraulic pumps, electromagnetic valves, sensors, ahydraulic unit 31 that is interposed between the master cylinder M/C and each of the wheel cylinders W/C and a control unit CU that is integrally mounted to thehydraulic unit 31 to control the electric motors and electromagnetic valves by processing information signals from the sensors. Of course, thehydraulic unit 31 and the control unit CU may have separate construction. - Referring to
FIG. 1 , there is schematically shown a hydraulic circuit of an automotive hydraulic brake system of thefirst embodiment 100 of the present invention. - In the drawing, denoted by
numeral 31 is a hydraulic unit. The hydraulic brake system of thefirst embodiment 100 generally comprises P-system and S-system that are fluidly connected to each other via so-called X-piping. - As is seen from
FIG. 1 , to the P-system, there are connected both a wheel cylinder W/C(FL) of a front left road wheel and a wheel cylinder W/C(RR) of a rear right road wheel, and to the S-system, there are connected both a wheel cylinder W/C(FR) of a front right road wheel and a wheel cylinder W/C(RL) of a rear left road wheel. - The P-system and S-system are equipped with respective pumps PP and PS which are driven by a single electric motor M. However, if desired, these pumps PP and PS may be driven by respective electric motors. As the pumps PP and PS, various types may be used.
- Denoted by reference BP is a brake pedal that is to be depressed by a driver for braking an associated motor vehicle. A brake switch BS is connected to the brake pedal BP to detect an operation condition of the brake pedal BP. The brake pedal BP is connected to a master cylinder M/C through an
input rod 1. - The master cylinder M/C is connected to intake ports of the two pumps PP and PS through
respective intake passages intake passage intake passage valve numeral 111, and a part that extends between the gate-invalve numeral 112. The detail of the gate-invalve - Between the master cylinder M/C and the gate-in
valve 2P, there is connected a pressure sensor PMC that detects a hydraulic pressure produced by the master cylinder M/C. - Between the master cylinder M/C and an outlet port of each pump PP or PS, there extends a passage (or discharge passage) 13P or 13S.
- Between the outlet port of each pump PP or PS and intake ports of the wheel cylinders W/C(FL) and W/C(RR) or [W/C(RL) and W/C(FR)], there extends a passage (or first hydraulic passage) 12P or 12S. On a part of the
passage 12P that extends to the wheel cylinder W/C(FL), there is mounted a solenoid-in valve 4FL, and on the other part of thepassage 12P that extends to the wheel cylinder W/C(RR), there is mounted a solenoid-in valve 4RR. Similarly, on a part of thepassage 12S that extends to the wheel cylinder W/C(FR), there is mounted a solenoid-in valve 4FR, and on the other part of thepassage 12S that extends to the wheel cylinder W/C(RL), there is mounted a solenoid-in valve 4RL. These solenoid-in valves 4FL, 4RR, 4FR and 4RL are of a normal open type electromagnetic valve. - On the
discharge passage check valve check valve - To the
passage 12P, there are connected a bypass passage 17FL that bypasses the solenoid-in valve 4FL and another bypass passage 17RR that bypasses the solenoid-in valve 4RR, and to thepassage 12S, there are connected a bypass passage 17FR that bypasses the solenoid-in valve 4FR and another bypass passage 17RL that bypasses the solenoid-in valve 4RL. Each of these bypass passages 17FL, 17RR, 17FR and 17RL is equipped with a check valve 10FL, 10RR, 10FR or 10RL. As shown, the check valve 10FL, 10RR, 10FR or 10RL is arranged to permit a fluid flow from the wheel cylinder W/C(FL), W/C(RR), W/C(FR) or W/C(RL) to the pump PP or PS and check a fluid flow from the pump PP or PS to the wheel cylinder W/C(FL), W/C(RR), W/C(FR) or W/C(RL). - As shown, an upstream end of the
passage discharge passage check valve - As shown, on the
discharge passage valve bypass passage valve discharge passage bypass passage check valve - To the inlet side of the pump PP or PS, there is connected a
reservoir outlet passage check valve reservoir - The wheel cylinder W/C(FL) or W/C(RR) and the
outlet passage 15P is connected through apassage 14P, and the wheel cylinder W/C(FR) or W/C(RL) and thepassage 15S is connected through apassage 14S. Thepassage outlet passage reservoir check valve passage 14P that extends to the wheel cylinder W/C(FL) or W/C(RR) is equipped with a solenoid-out valve 5FL or 5RR, and a part of thepassage 14S that extends to the wheel cylinder W/C(FR) or W/C(RL) is equipped with a solenoid-out valve 5FR or 5RL. These solenoid-out valves 5FL, 5RR, 5FR and 5RL are of a normal close type electromagnetic valve. - The
hydraulic unit 31 comprises two master cylinder ports MPT through which feeding/receiving of a brake fluid between the master cylinder M/C and the P-system and that between the master cylinder M/C and the S-system are carried out respectively and four wheel cylinder ports WPT through which feeding/receiving of the brake fluid between thehydraulic unit 31 and the wheel cylinder W/C(FL), that between thehydraulic unit 31 and the wheel cylinder W/C(RR), that between thehydraulic unit 31 and the wheel cylinder W/C(FR) and that between thehydraulic unit 31 and the wheel cylinder W/C(RL) are carried out respectively. A brake piping is incorporated with the above-mentioned two master cylinder ports MPT and the four wheel cylinder ports WPT in such a manner as is shown inFIG. 1 . - Upon receiving information signals from various sensors, such as a road wheel speed sensor, a yaw rate sensor, an acceleration sensor and the like, the control unit CU processes the information signals and issues various instruction signals to various hardware elements for suitably carrying out an anti-lock brake control (viz., ABS control), a vehicle dynamics control (viz., VDC), an active cruise control (viz., ACC), etc., in accordance with an operation condition of the vehicle. The hardware elements are the electric motor M, the gate-out
valves - In the
first embodiment 100, the gate-outvalves first embodiment 100, the electric motor M is of a speed control type. However, if desired, the motor M may be of an ON/OFF type. - In the following description, various operations by which the pressure in each wheel cylinder W/C(FL), W/C(RR), W/C(FR) or W/C(RL) is increased will be referred to as “pump-up operation”.
- Referring to
FIGS. 2A and 2B , there is schematically shown the gate-invalve FIG. 2A shows an open condition of thevalve FIG. 2B shows a closed condition of thevalve valve body 81 is intimately seated on the valve seat surface. - As is seen from
FIG. 2A , the gate-invalve housing 86 that generally includes aball receiving chamber 860 and apiston receiving chamber 861 that are fluidly connected to each other through acylindrical passage 86 b as shown. A valve body (or ball) 81 is movably received in theball receiving chamber 860 to serve as a valve device, and acircular piston 83 is axially movably received in thepiston receiving chamber 861. As will be apparent hereinafter, thepiston receiving chamber 861 serves as a brake fluid reservoir. - The
housing 86 has above theball receiving chamber 860 anopening 87 to which the above-mentioned mastercylinder side passage 111 is connected. Theball receiving chamber 860 includes acylindrical chamber portion 86 a 1 in which theball 81 is axially movable, and a conical chamber portion that is mated with a lower end of thecylindrical chamber portion 86 a 1. A conical surface of the conical chamber portion, which serves as a valve seat for theball 81, is denoted by numeral 86 a. - As is seen from
FIG. 2B , when theball 81 is operatively put on thevalve seat surface 86 a to cause the gate-invale valve seat surface 86 a obtains an effective pressure receiving area S2. It is to be noted that the effective pressure receiving area S2 is an area of a circular tangential line described between theball 81 and thevalve seat surface 86 a. A diameter of the circular tangential line is denoted by reference “D”. - As is seen from
FIGS. 2A an 2B, thecylindrical passage 86 b has a diameter is smaller than the diameter of the circular tangential line D. Thecylindrical passage 86 b has aradially extending passage 88 to which the above-mentioned “pump intake side passage” 112 is connected. - The
piston receiving chamber 861 comprises a circularupper surface 86 c through which thecylindrical passage 86 b is exposed to thepiston receiving chamber 861, acylindrical wall 86 d that has the same diameter as the circularupper surface 86 c and a circularlower surface 86 e that has an opening “AO” exposed to the outside air. - Around the
piston 83, there is disposed anannular seal member 84 for achieving a sealing between upper and lower chamber parts of thepiston receiving chambers 861. Only upper chamber part (viz., reservoir chamber) is denoted bynumeral 89. A biasingspring 85 is disposed in the lower chamber part for biasing thepiston 83 upward, that is, in a direction of theball receiving chamber 860. Thus, as will be seen fromFIG. 2B , when the brake fluid is forced to flow into theupper chamber part 89, thepiston 83 is moved down against the biasing force of thespring 85 allowing theupper chamber part 89 to serve as a brake fluid reservoir. When the brake fluid has an atmospheric pressure, that is, when the brake fluid is not compressed, thepiston 83 is moved up to the uppermost position by the biasing force of thespring 85 as is shown byFIG. 2A . That is, a given set load is kept applied to the biasingspring 85. - The
piston 83 has apin 82 that is inserted into thecylindrical passage 86 b. Preferably, thepin 82 is welded to thepiston 83. As shown, thepin 82 has a diameter smaller than that of thecylindrical passage 86 b, so that a cylindrical clearance is defined between thepin 82 and an inner wall of thecylindrical passage 86 b. As will become apparent from the following description, thepin 82 pushes up theball 81 from thevalve seat surface 86 a when thepiston 83 is moved up to a certain position. - For ease of understanding, the following description on the operation will be commenced with respect to an initial condition of the hydraulic brake system wherein the brake pedal B is kept released. Then, the description will be directed to a condition wherein the brake pedal B is depressed to actuate the master cylinder M/C and then to a condition wherein due to the above-mentioned pump-up operation, a compressed brake fluid is led from the master cylinder M/C to the wheel cylinders W/C(FL), W/C(RR), W/C(FR) and W/C(RL).
- In the following, the master cylinder pressure is denoted by Pm, the effective pressure receiving area of the
piston 83 is denoted by S1, the effective pressure receiving area of theball 81 obtained when theball 81 is operatively put on thevalve seat surface 86 a is denoted by S2 (which is smaller than S1), and the set load of the biasingspring 85 is denoted by f1. Strictly speaking, the set load f1 of thespring 85 varies in accordance with shrinkage of the spring. However, since the variation is very small, the description will be made considering that the set load f1 is constant. - [Step 1: from Initial Condition to Starting of Master Cylinder Actuation]
-
FIG. 2A shows a condition of the gate-invalve spring 85, thepin 82 pushes up theball 81 from thevalve seat surface 86 a thereby to cause the gate-invalve - When now the master cylinder pressure Pm is generated due to depression of the brake pedal B by a driver, the master cylinder pressure Pm is applied to the
piston 83 through thepassage 86 b thereby to push down thepiston 83 with a certain force F (=Pm×S1). When the master cylinder pressure Pm is not sufficiently high, the force F produced is smaller than the set load f1 of the biasingspring 85. Under this condition, thecylindrical chamber portion 86 a 1, the pumpintake side passage 112 and the upper chamber part (or brake fluid reservoir) 89 of thepiston receiving chamber 861 are kept communicated. As is seen fromFIG. 1 , even under this condition, due to provision of thecheck valve valve reservoir reservoir - When now the master cylinder pressure Pm is increased and the force F produced becomes larger than f1, the
piston 83 is moved downward and thus thepin 82 is moved down together with theball 81. Under this condition, an inequality “f1<Pm×S1” is established. - When, due to the downward movement, the
ball 81 becomes put on thevalve seat surface 86 a as is shown inFIG. 2B , the fluid connection between the mastercylinder side passage 111 and the pumpintake side passage 112 is closed. In this condition, hydraulic pressures applied to theball 81 are represented by the following. - The master cylinder side of the ball: Pm
- The pump intake side: f1/S1 (=Ps0)
- If the master cylinder pressure Pm at the time when the
ball 81 is intimately put on thevalve seat surface 86 a is represented by Pm0, the inequality “Pm0×S1>f1” brings about the inequality “S1>f1/Pm0”. If this inequality “S1>f1/Pm0” is modified by using the above-mentioned relation, the equality “Ps0=f1/S1” brings about the inequality “Pm0>Ps0”. Accordingly, even when thepassage 86 b is closed by theball 81, it never occurs that the pressure “Ps0” of the pump intake side becomes higher than “f1/S1”. That is, under such closed condition, the pressure “Ps0” is kept lower than the master cylinder pressure “Pm0”. - When now the pump PP or PS is operated, the brake fluid is led thereinto from the pump
intake side passage 112, and thus, the pressure “Ps” at the pump intake side becomes lower than “Ps0”. Due to this reduction of the pressure “Ps” at the pump intake side, the force for pressing down thepiston 83 is reduced. Accordingly, if the inequality “f1−(Ps×S1)>Pm×S2”, theball 81 is moved upward. It is now to be noted that “Pm×S2” is the force of pressing down thepiston 83. Because of the upward movement, theball 81 becomes separated from thevalve seat surface 86 a thereby establishing the fluid communication between the mastercylinder side passage 111 and the pump intake side passage 112 (The pressure Ps of the pump intake side at this time is a third given pressure.) Accordingly, the pump PP or PS is able to intake the brake fluid from the master cylinder M/C. Since the pressure “Ps” becomes 0 (zero) instantly upon operation of the pump PP or PS, an inequality “f1>Pm×S2” is established. - [Comparison with Known Automotive Hydraulic Brake System]
-
FIGS. 3A and 3B are sectional views of a known internal reservoir disclosed in the above-mentioned Japanese Laid-open Patent Application (Tokkai) 2007-238095. As is seen from these drawings, the known internal reservoir generally comprises a ball (or valve body), a piston, a pin and a biasing spring. The internal reservoir functions not only to reserve a brake fluid from a pressure reducing control valve but also to adjust a hydraulic pressure that is applied from a master cylinder to a pump intake side. For simplifying the following explanation on the known internal reservoir, the pressure receiving area of the piston will be represented by “S1”, the effective pressure receiving area of the ball will be represented by “S2” and the set load of the spring will be represented by “F1”. Actually, the internal reservoir has both a function of a reservoir and a function of a gate-in valve, and the OPEN/CLOSE operation of the internal reservoir is mechanically carried out. However, as has been mentioned hereinabove, in this known internal reservoir, for obtaining a smoothed braking operation against a higher master cylinder, it is necessary to increase the set load of the biasing spring or reduce the pressure reducing area of the ball. Such necessity will be easily understood from the following description. -
FIG. 4 is a graph showing a relationship between a brake fluid pressure and a set load (or spring force) of a biasing spring. As is seen from the graph, when the set load of the spring is set high, the pressure “Pr” of the brake fluid from the pressure reducing control valve becomes increased because the pressure receiving area “S1” of the piston is fixed. This means that a reducible fluid pressure from the wheel cylinders of the road wheels shows a high value and thus a sufficient pressure reduction performance to a low μ road is not obtained. While, if the pressure receiving area of the ball is set to a smaller value, a sufficient pressure reduction performance to the low μ road may be obtained. However, in this case, an intake resistance appearing when the brake fluid is sucked from the master cylinder side, such as at the time of pump up operation caused by an auto-braking, is increased and thus the pressure increasing performance is lowered. If the set load (or spring force) of the biasing spring is set small, it becomes possible to lower the pressure “Pr” of the brake fluid flowing from the pressure reducing control valve, as is indicated by the set load “F1′” of the graph ofFIG. 4 . However, in this case, a sufficient pressure adjusting operation is expected only when the master cylinder pressure Pm is low, and thus, the range within which a sufficient pressure adjusting operation is carried out is reduced. That is, for increasing the range for the sufficient pressure adjusting operation, it is effective to increase the set load of the biasing spring. However, in this case, such sufficient pressure adjusting operation is not expected in a case wherein the pressure “Pr” of the brake fluid from the pressure reducing control valve is low. - In view of the above, in the
first embodiment 100 of the present invention, there is provided an automotive hydraulic brake system including a valve construction that allows flow of a brake fluid from a master cylinder side to a pump upon operation of the pump, and causes the brake fluid flowing from a pressure reducing control valve to be reserved by areservoir spring 85 of the gate-invalve reservoir reservoir - Thus, in the
first embodiment 100 of the present invention, by increasing the cross section of thecylindrical passage 86 b of the gate-invalve ball 81 can be increased and thus the fluid intake resistance of thepump reservoir -
FIG. 5 is a time chart showing a pump up operation of the hydraulic brake system of thefirst embodiment 100. As has been mentioned hereinabove, the pump up operation is the operation that is carried out when the master cylinder pressure Pm is practically applied to the hydraulic circuit of the brake system. - At the time t51, the brake pedal BP is depressed by a driver. Upon this, both the master cylinder pressure Pm and the wheel cylinder pressure Pw start to increase. At the time t52, that is, when “f1<Pm×S1” is established, the gate-in
valve - At the time t53, an instruction signal is issued for increasing the wheel cylinder pressure Pw. Upon this, the gate-out
valve valve FIG. 2B ) of the gate-invalve - When, at the time t54, the pump intake side pressure Ps becomes lower than the third given pressure, the gate-in
valve valve - When, at the time t55, the instruction signal for increasing the wheel cylinder pressure Pw is ceased, the motor M is de-energized. Upon this, the pump intake side pressure Ps starts to increase. When, at the time t56, the pump intake side pressure Ps exceeds the third given pressure, the gate-in
valve - When, at the time t57, an instruction signal is issued for reducing the pressure of the brake fluid fed to the wheel cylinders, the gate-out
valve valve - At the time t59, the master cylinder pressure Pm, the wheel cylinder pressure Pw and the pump intake side pressure Ps become 0 (zero).
- In the
first embodiment 100, thecheck valve such check valve valve reservoir such check valve - In the following, nine advantages of the automotive hydraulic brake system of the
first embodiment 100 will be enumerated. - (1) There is employed a unique circuit that comprises the
intake passage discharge passage passage discharge passage passage reservoir outlet passage reservoir intake passage valve intake passage first embodiment 100 of the present invention, besides theconventional reservoir valve intake passage 11P in accordance with the pressure difference between the master cylinder pressure Pm and the pump intake side pressure Ps. Thus, the characteristic of the gate-invalve - (2) The gate-in
valve intake passage intake passage valve intake passage intake passage - (3) Under a condition wherein the master cylinder pressure Pm is within a range from the first given pressure to the second given pressure, the gate-in
valve valve - (4) To the
outlet passage check valve valve reservoir reservoir - (5) The gate-in
valve intake passage intake passage piston 83 that is movable together with theball 81 through thepin 82 and the biasingspring 85 that biases thepiston 83 toward theball 81. Thus, the gate-invalve - (6) When the master cylinder pressure is represented by Pm, the sectional area of the
piston 83 is represented by S1, the sectional area of the intake passage that is closed by theball 81 is represented by S2 and the set load (or spring force) of the biasingspring 85 is represented by f1, the set load f1 of the biasingspring 85 can be defined or represented by “Pm×S1>f1>Pm×S2”. This inequality has substantially no influence on the performance of thereservoir - (7) Since f1/S1, f1/S2 and 0<f1/S1 can be represented by first, second and third given values or condition, the gate-in
valve - (8) The hydraulic unit 31 having therein the pumps PP and PS driven by the electric motor M comprises the two master cylinder ports MPT through which the master cylinder M/C and internal passages are connected, the intake passages 11P and 11S each connecting the master cylinder port MPT with an intake side of the corresponding pump PP or PS, the passages 13P and 13S each being branched from the intake passage 11P or 11S to connect the discharge side of the pump PP or PS with the corresponding master cylinder port MPT, the wheel cylinder ports WPT each connecting the passage 12P or 12S branched from the passage 13P or 13S with the corresponding one of the wheel cylinders W/C, the reservoirs 16P and 16S each receiving the brake fluid from the wheel cylinders W/C through corresponding wheel cylinder port WPT, the ports 14P and 14S each connecting the wheel cylinder port WPT with the corresponding reservoir 16P or 16S, the outlet passage 15P or 15S each connecting the reservoir 16P or 16S with the corresponding intake passage 11P or 11S, and the gate-in valves 2P and 2S each being mounted in the intake passage 11P or 11S and functioning to open and close the intake passage 11P or 11S in accordance with a pressure difference between pressures appearing in the intake passage 11P or 11S at front and rear portions of the gate-in valve 2P or 2S. That is, in the
first embodiment 100 of the present invention, besides thereservoirs valves corresponding intake passage valves - (9) The hydraulic brake system of the
first embodiment 100 comprises thehydraulic unit 31 that has therein the pumps PP and PS, theintake passages hydraulic unit 31 and the intake side of the corresponding pump PP or PS, thedischarge passages hydraulic unit 31, thepassages discharge passage passages reservoirs hydraulic unit 31, and the gate-invalves intake passage intake passage intake passage valve hydraulic unit 31 through the gate-invalve first embodiment 100, besides thereservoirs valves corresponding intake passage valves - In the following, an automotive hydraulic brake system of a
second embodiment 200 of the present invention will be described with reference toFIG. 6 . - Since the brake system of the
second embodiment 200 is similar to that of the above-mentionedfirst embodiment 100, only portions or parts that are different from those of thefirst embodiment 100 will be described in detail in the following. - Referring to
FIG. 6 , there is schematically shown a hydraulic circuit of the automotive hydraulic brake system of thesecond embodiment 200 of the present invention. - As is seen from the drawing, in this
second embodiment 200, in place of thecheck valves first embodiment 100,electromagnetic valves intake passages electromagnetic valve intake passage valve outlet passage electromagnetic valve outlet passage valve - In the following, operation of the
second embodiment 200 will be described with the aid ofFIG. 6 . - In normal braking, the
electromagnetic valves electromagnetic valves intake passages valves valves reservoirs first embodiment 100 is obtained since theelectromagnetic valves reservoirs valves reservoirs electromagnetic valves reservoirs - Accordingly, in the
second embodiment 200, besides the above-mentioned nine advantages (1) to (9) possessed by thefirst embodiment 100, the following advantage is obtained. - (10) Due to provision of the
electromagnetic valves respective intake passages reservoirs - In the following, an automotive hydraulic brake system of a
third embodiment 300 of the present invention will be described with reference toFIG. 7 . - Like in the above-mentioned
second embodiment 200, the brake system of thethird embodiment 300 is similar to that of the above-mentionedfirst embodiment 100, only portions or parts that are different from those of thefirst embodiment 100 will be described in detail in the following. - Referring to
FIG. 7 , there is schematically shown a hydraulic circuit of the automotive hydraulic brake system of thethird embodiment 300 of the present invention. - As is seen from the drawing, in this
third embodiment 300, in place of thecheck valves electromagnetic valves 81P and 81S are used which are operatively mounted on theoutlet passages electromagnetic valve 81P or 81S is mounted on theoutlet passage intake passage valve reservoir electromagnetic valve 81P or 81S carries out a suitable ON/OFF (or open/close) operation to selectively open and close theoutlet passage reservoir - In the following, operation of the
third embodiment 300 will be described with the aid ofFIG. 7 . - Only when it is needed to discharge the brake fluid, which has been reserved upon the anti-lock braking operation (viz., ABS control), from the
reservoirs electromagnetic valves 81P and 81S are opened, and in other cases, such as, the case of normal braking to and the case of controlling the wheel cylinder pressure Pw higher than the master cylinder pressure Pm, theelectromagnetic valves 81P or 81S are closed. Accordingly, substantially same advantages as those of the above-mentionedfirst embodiment 100 are obtained also in thisthird embodiment 300. Furthermore, in normal braking, until the time when, due to addition of the master cylinder pressure Pm to the gate-invalves valves reservoirs electromagnetic valves 81P and 81S are kept closed, and thus, the brake fluid that is to be sucked by the pumps PP and PS is supplied from only the master cylinder side. - Accordingly, in the
third embodiment 300, besides the above-mentioned nine advantages (1) to (9) possessed by thefirst embodiment 100, the following advantage is obtained. - (11) Due to provision of the
electromagnetic valves 81P and 81S on therespective outlet passages reservoirs - The entire contents of Japanese Patent Application 2009-072248 filed Mar. 24, 2009 are incorporated herein by reference.
- Although the invention has been described above with reference to embodiments of the invention, the invention is not limited to such embodiments as described above. Various modifications and variations of such embodiments may be carried out by those skilled in the art, in light of the above description.
Claims (5)
1. A hydraulic brake system comprising:
an intake passage connecting a master cylinder to an intake side of a fluid pump;
a discharge passage connecting a discharge side of the fluid pump to the master cylinder;
a first passage branched from the discharge passage and connected to a wheel cylinder;
a pressure reduction passage connected to a reservoir that reserves therein a pressure-reduced brake fluid from the wheel cylinder;
an outlet passage connecting the reservoir to the intake passage; and
a gate-in valve installed in the intake passage and closed when applied with a master cylinder pressure from the master cylinder, the gate-in valve selectively opening and closing the intake passage when the master cylinder pressure is applied to the gate-in valve and the fluid pump is in operation,
wherein when the master cylinder pressure is applied to the gate-in valve, the fluid pump takes therein a brake fluid through the gate-in valve that is carrying out the opening/closing operation.
2. A hydraulic brake system comprising:
a fluid pump driven by an electric motor; and
a housing that houses therein the fluid pump,
wherein the housing comprises:
a master cylinder port connected to a master cylinder that is arranged outside the housing;
an intake passage connecting the master cylinder port to an intake side of the fluid pump;
a discharge passage connecting a discharge side of the fluid pump to the master cylinder port;
a first passage branched from the discharged passage;
a wheel cylinder port connecting the first passage to a wheel cylinder that is arranged outside of the housing;
a pressure reduction passage through which a brake fluid in the wheel cylinder is led into a reservoir through the wheel cylinder port; and
an outlet passage connecting the reservoir to the intake passage,
wherein the intake passage is provided with a pressure valve that carries out an open/close operation in accordance with a pressure difference between a pressure appearing at an upstream portion of the intake passage and a pressure appearing at a downstream portion of the intake passage with respect to the pressure valve,
wherein the pressure valve is set to carry out the open/close operation when the master cylinder pressure is applied thereto and the fluid pump is in operation, and
wherein the fluid pump is set to suck therein the brake fluid through the pressure valve.
3. A hydraulic brake system as claimed in claim 2 , further comprising a check valve that is installed in the outlet passage at a position between a first point where the intake passage is connected to the outlet passage and a second point where the pressure reduction passage is connected to the outlet passage and arranged to suppress a flow of the brake fluid in a direction from the first point toward the reservoir while permitting a reversed flow of the brake fluid.
4. A hydraulic brake system as claimed in claim 2 , further comprising an electromagnetic valve that is installed in the intake passage at a position between a first position where the intake passage is connected to the gate-in valve and a second position where the intake passage is connected to the outlet passage and arranged to selectively open and close the intake passage.
5. A hydraulic brake system as claimed in claim 2 , further comprising an electromagnetic valve that is installed in the outlet passage at a position between a first point where the intake passage is connected to the outlet passage and a second point where the pressure reduction passage is connected to the outlet passage and arranged to selectively open and close the outlet passage.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/687,303 US20130088076A1 (en) | 2009-03-24 | 2012-11-28 | Automotive Hydraulic Brake System |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2009-072248 | 2009-03-24 | ||
JP2009072248A JP5080521B2 (en) | 2009-03-24 | 2009-03-24 | Brake device |
US12/683,139 US8342617B2 (en) | 2009-03-24 | 2010-01-06 | Automotive hydraulic brake system |
US13/687,303 US20130088076A1 (en) | 2009-03-24 | 2012-11-28 | Automotive Hydraulic Brake System |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/683,139 Continuation US8342617B2 (en) | 2009-03-24 | 2010-01-06 | Automotive hydraulic brake system |
Publications (1)
Publication Number | Publication Date |
---|---|
US20130088076A1 true US20130088076A1 (en) | 2013-04-11 |
Family
ID=42783231
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/683,139 Expired - Fee Related US8342617B2 (en) | 2009-03-24 | 2010-01-06 | Automotive hydraulic brake system |
US13/687,303 Abandoned US20130088076A1 (en) | 2009-03-24 | 2012-11-28 | Automotive Hydraulic Brake System |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/683,139 Expired - Fee Related US8342617B2 (en) | 2009-03-24 | 2010-01-06 | Automotive hydraulic brake system |
Country Status (2)
Country | Link |
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US (2) | US8342617B2 (en) |
JP (1) | JP5080521B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9010362B2 (en) | 2012-11-14 | 2015-04-21 | Denso Corporation | Pressure control reservoir with check valve |
US9260100B2 (en) | 2012-10-26 | 2016-02-16 | Denso Corporation | Pressure control reservoir with check valve |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102007038397A1 (en) * | 2007-08-14 | 2009-02-19 | Robert Bosch Gmbh | Braking system for a vehicle |
DE102008002539A1 (en) * | 2008-06-19 | 2009-12-24 | Robert Bosch Gmbh | Control valve for a vehicle brake system and corresponding vehicle brake system |
JP5080521B2 (en) * | 2009-03-24 | 2012-11-21 | 日立オートモティブシステムズ株式会社 | Brake device |
EP2670640A1 (en) * | 2011-01-31 | 2013-12-11 | Robert Bosch GmbH | Method for circuit separation testing in a double gearwheel pump |
JP5848980B2 (en) * | 2012-02-09 | 2016-01-27 | 日立オートモティブシステムズ株式会社 | Brake device |
JP5814158B2 (en) * | 2012-02-27 | 2015-11-17 | 日立オートモティブシステムズ株式会社 | Brake control device |
DE102012212546A1 (en) * | 2012-07-18 | 2014-01-23 | Robert Bosch Gmbh | Fluidically controlled pressure switching valve for a vehicle brake system and vehicle brake system |
DE102012218544A1 (en) * | 2012-10-11 | 2014-04-17 | Robert Bosch Gmbh | Hydraulically controlled storage chamber valve |
JP2015116878A (en) * | 2013-12-17 | 2015-06-25 | 株式会社デンソー | Pressure-adjusting reservoir |
JP6354692B2 (en) * | 2015-07-24 | 2018-07-11 | 株式会社アドヴィックス | Brake control device for vehicle |
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US5356210A (en) * | 1991-03-16 | 1994-10-18 | Alfred Teves Gmbh | Anti-lock hydraulic brake system |
US5538336A (en) * | 1994-12-23 | 1996-07-23 | General Motors Corporation | Integrated ABS/TCS hydraulic modulator braking system |
US8342617B2 (en) * | 2009-03-24 | 2013-01-01 | Hitachi Automotive Systems, Ltd. | Automotive hydraulic brake system |
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DE4202388A1 (en) | 1992-01-29 | 1993-08-05 | Bosch Gmbh Robert | Vehicular hydraulic antilock braking system with wheel-slip controller - has blocking valve in pump induction line with steel ball and seating opened by impact piston |
JPH0655909U (en) * | 1993-01-14 | 1994-08-02 | 住友電気工業株式会社 | Brake fluid pressure control device |
DE19626289B4 (en) * | 1996-07-01 | 2008-08-14 | Continental Teves Ag & Co. Ohg | Hydraulic brake system with a return pump |
JP4395793B2 (en) * | 1997-02-03 | 2010-01-13 | 株式会社デンソー | Hydraulic circuit provided with rotary pump and brake device using this hydraulic circuit |
JP3937554B2 (en) * | 1998-01-29 | 2007-06-27 | 株式会社デンソー | Brake control actuator |
JP3637813B2 (en) * | 1998-09-07 | 2005-04-13 | 株式会社デンソー | Pressure regulating reservoir for ABS and vehicle brake device using the same |
JP4191332B2 (en) * | 1999-08-26 | 2008-12-03 | 日信工業株式会社 | Brake hydraulic control device for vehicle |
-
2009
- 2009-03-24 JP JP2009072248A patent/JP5080521B2/en active Active
-
2010
- 2010-01-06 US US12/683,139 patent/US8342617B2/en not_active Expired - Fee Related
-
2012
- 2012-11-28 US US13/687,303 patent/US20130088076A1/en not_active Abandoned
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Publication number | Priority date | Publication date | Assignee | Title |
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US5356210A (en) * | 1991-03-16 | 1994-10-18 | Alfred Teves Gmbh | Anti-lock hydraulic brake system |
US5538336A (en) * | 1994-12-23 | 1996-07-23 | General Motors Corporation | Integrated ABS/TCS hydraulic modulator braking system |
US8342617B2 (en) * | 2009-03-24 | 2013-01-01 | Hitachi Automotive Systems, Ltd. | Automotive hydraulic brake system |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9260100B2 (en) | 2012-10-26 | 2016-02-16 | Denso Corporation | Pressure control reservoir with check valve |
US9010362B2 (en) | 2012-11-14 | 2015-04-21 | Denso Corporation | Pressure control reservoir with check valve |
Also Published As
Publication number | Publication date |
---|---|
US8342617B2 (en) | 2013-01-01 |
JP2010221890A (en) | 2010-10-07 |
JP5080521B2 (en) | 2012-11-21 |
US20100244553A1 (en) | 2010-09-30 |
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Legal Events
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AS | Assignment |
Owner name: HITACHI AUTOMOTIVE SYSTEMS, LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:OOSAWA, TOSHIYA;REEL/FRAME:029363/0853 Effective date: 20121122 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |