Liquid pressure generator

Abstract

To shorten the axial dimension in a liquid pressure generator.SOLUTION: A liquid pressure generator comprises: an electric motor that outputs rotational power Tm; a conversion mechanism that converts the rotational power Tm input to a rotating member into linear power Fn of a linear motion member to output the same; a piston NC that is inserted into a cylinder CC and moves with the linear power Fn to increase the liquid pressure in the cylinder CC; a housing HG in which the cylinder CC is formed and which holds a sealing member that seals the cylinder CC and the piston NC; and a rotation prevention member that is fixed to the housing HG and prevents the linear motion member from rotating about the rotation axis of the rotating member. In the liquid pressure generator, when parallel projection is performed in a direction perpendicular to the rotation axis, a portion of a projection Zms of a seal groove Ms1 that fixes the sealing member overlaps with a portion of a projection Zam of a hole Amd that fixes the rotation prevention member.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a hydraulic pressure generating device. [Background technology]

[0002] Patent Document 1 describes a piston pump assembly including an electric motor, a planetary gear, a worm gear, and a piston displaceable in a cylinder. Specifically, it describes that, to prevent the piston from rotating in the cylinder, the piston includes a ring connected to the piston by form fitting, and includes a semicircular groove on its outer periphery, into which a cylinder pin fixed in parallel in the cylinder is engaged. The device in Patent Document 1 uses an electric motor as a power source to generate hydraulic pressure by the movement of the piston, but in such a hydraulic pressure generating device, it is desirable to reduce the axial size in terms of mounting it on a vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2021 / 0122342 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above problems, an object of the present invention is to provide a hydraulic pressure generating device whose axial dimension can be shortened. [Means for solving the problem]

[0005] The hydraulic pressure generating device (PS) of the present invention comprises an electric motor (MT) which outputs a rotational power (Tm), a conversion mechanism (GH) which outputs the rotational power (Tm) input to a rotating member (BK) as a linear power (Fn) of a linear moving member (BD), a piston (NC) which is inserted into a cylinder (CC) and moves by the linear power (Fn) to increase the hydraulic pressure (Pc) of the cylinder (CC), a housing (HG) in which the cylinder (CC) is formed and which holds a sealing member (SL1) that seals the cylinder (CC) and the piston (NC), and a rotation prevention member (MD) which is fixed to the housing (HG) and prevents the linear moving member (BD) from rotating around the rotation axis (Jk) of the rotating member (BK).

[0006] In the hydraulic pressure generating device (PS) according to the present invention, when projected parallel to a direction (Hk) perpendicular to the rotation axis (Jk), a projection (Zms) of a seal groove (Ms1) for fixing the seal member (SL1) and a projection (Zam) of a hole (Amd) for fixing the anti-rotation member (MD) partially overlap. For example, the linear motion member (BD) has a notch, and the notch engages with the anti-rotation member (MD), thereby preventing the rotation. Alternatively, the piston (NC) has a notch and is fixed to the linear motion member (BD), and the notch engages with the anti-rotation member (MD), thereby preventing the rotation.

[0007] To fix the anti-rotation member MD, the mounting hole Amd needs to have a depth Lz (length in the axial direction Hj). With the above configuration, the depth required for the mounting hole Amd can be reduced, and the axial dimension (axial length) of the device can be shortened. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram for explaining the overall configuration of a braking control device SC. [Diagram 2] FIG. 2 is a partial cross-sectional view for explaining a first embodiment of a hydraulic pressure generating unit PS. [Diagram 3] 11 is a partial cross-sectional view for explaining a method of fixing the anti-rotation member MD to the housing HG. FIG. [Figure 4] FIG. 4 is a partial cross-sectional view for explaining a second embodiment of the liquid pressure generating unit PS. [Diagram 5] FIG. 11 is a partial cross-sectional view for explaining a third embodiment of a hydraulic pressure generating unit PS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Symbols for components, etc. and suffixes at the end of the symbols> In the following description, components, calculation processes, signals, characteristics, and values ​​with the same symbol, such as "CW", have the same function. The suffixes "f" and "r" at the end of the symbol for each wheel are generic symbols that indicate whether it is related to the front or rear wheel system. For example, the wheel cylinder CW provided on each wheel is written as "front wheel cylinder CWf, rear wheel cylinder CWr". Furthermore, the suffixes "f" and "r" at the end of the symbol may be omitted. When the suffixes "f" and "r" are omitted, each symbol represents its generic name. For example, "CW" is a generic name for wheel cylinders provided on the front and rear wheels of a vehicle. Furthermore, "CW" as a generic name can also be written as "CW (= CWf, CWr)".

[0010] The first actuator YA of the first braking unit SA, the second actuator YB of the second braking unit SB, and the wheel cylinder CW are connected by a fluid path (communication path HS). Furthermore, in the first and second actuators YA and YB, various components (PS, etc.) are connected by fluid paths. Here, the "fluid path" is a path for moving the brake fluid BF (working fluid), and corresponds to piping, flow paths in the actuators, hoses, etc. In the following explanation, the communication path HS, reservoir path HR, input path HN, servo path HU, supply path HH, etc. are fluid paths.

[0011] <Vehicle Brake Control Device SC> The overall configuration of the brake control device SC including the hydraulic pressure generating unit PS will be described with reference to the schematic diagram of Figure 1. For example, the brake control device SC is applied to a hybrid vehicle equipped with an electric motor for driving, or an electric vehicle.

[0012] The vehicle is equipped with a regenerative device KG. The regenerative device KG is composed of a generator GN for energy regeneration (also called an "electric motor / generator" or a "regenerative generator"), a control unit EG for the regenerative device KG (also called a "regenerative controller"), and a regenerative storage battery (not shown). The regenerative generator GN also serves as an electric motor for driving. In regenerative braking, the electric motor / generator GN operates as a generator, and the generated electric power is stored in the regenerative storage battery via the regenerative controller EG. At this time, a regenerative braking force Fg acts on the wheels. For example, the regenerative device KG is provided on the front wheels WHf, and a regenerative braking force Fg is generated on the front wheels WHf.

[0013] The front and rear wheels WHf, WHr of the vehicle are provided with braking devices SX (=SXf, SXr). The braking devices SX are composed of a brake caliper, a friction member (e.g., brake pad), and a rotating member KT (e.g., brake disc). The brake caliper (not shown) is provided with a wheel cylinder CW (=CWf, CWr). A hydraulic pressure Pw (referred to as "wheel pressure") in the wheel cylinder CW presses the friction member (not shown) against the rotating member KT (=KTf, KTr) fixed to each wheel WH, thereby applying a braking torque Tb to the wheel WH. As a result, a hydraulic braking force Fp is generated in the wheel WH.

[0014] The vehicle is equipped with a brake operating member BP and various sensors (SP, etc.). The brake operating member BP (e.g., a brake pedal) is an operating member for the driver to decelerate the vehicle. The vehicle is provided with an operation displacement sensor SP that detects an operation displacement Sp of the brake operating member BP. The operation displacement Sp is one of state quantities (state variables) that indicate the operation amount of the brake operating member BP. In addition to the operation displacement sensor SP, a hydraulic pressure Pn (referred to as "input pressure") in an input chamber Rn (described later) is adopted as another state quantity that indicates the braking operation amount. The input pressure Pn is detected by an input pressure sensor PN. The operation displacement Sp, the input pressure Pn, etc. are collectively referred to as the "braking operation amount Ba." Moreover, a sensor that detects the braking operation amount Ba, such as the operation displacement sensor SP or the input pressure sensor PN, is referred to as the "braking operation amount sensor BA."

[0015] The vehicle is equipped with a brake control device SC. The brake control device SC employs a so-called front and rear type (also called "type II") brake system as two systems. The brake control device SC adjusts the actual wheel pressure Pw of each wheel cylinder CW. The brake control device SC is composed of two brake units SA and SB.

[0016] <First braking unit SA> The first braking unit SA adjusts the hydraulic pressures Pwf, Pwr (front and rear wheel pressures) of the front and rear wheel cylinders CWf, CWr in response to the operation of a brake operating member BP (brake pedal). The first braking unit SA is composed of a first actuator YA and a first controller EA.

[0017] <First actuator YA> The first actuator YA is composed of an apply unit AP, a hydraulic pressure generating unit PS, and an input unit NR.

[0018] [Apply Unit AP] In response to the operation of the brake operating member BP, a supply pressure Pm is output from the apply unit AP. The apply unit AP is composed of a single-type master cylinder CM and a master piston NM.

[0019] A master piston NM is inserted into the single-type master cylinder CM. The interior of the master cylinder CM is divided into three hydraulic chambers Rm, Ru, and Rs by the master piston NM. The master chamber Rm is formed by the bottom of the master cylinder CM and the master piston NM. Furthermore, the interior of the master cylinder CM is divided into a servo chamber Ru and a reaction chamber Rs by a flange portion Tu of the master piston NM. Here, the pressure-receiving area rm of the master chamber Rm and the pressure-receiving area ru of the servo chamber Ru are set to be equal.

[0020] When braking is not being performed, the master piston NM is in the most retreated position (i.e., the position where the volume of the master chamber Rm is maximum). In this state, the master chamber Rm of the master cylinder CM is connected to the master reservoir RV. Brake fluid BF is stored inside the master reservoir RV (also called the "atmospheric pressure reservoir"). When the brake operating member BP is operated, the master piston NM is moved in the forward direction Da (the direction in which the volume of the master chamber Rm decreases). This movement blocks communication between the master chamber Rm and the master reservoir RV. Then, when the master piston NM is further moved in the forward direction Da, the supply pressure Pm (the internal pressure of the master chamber Rm, also called the "master pressure") is increased from "0 (atmospheric pressure)". As a result, the brake fluid BF pressurized to the supply pressure Pm is output (pressurized and fed) from the master chamber Rm of the master cylinder CM.

[0021] [Liquid pressure generating unit PS] The hydraulic pressure generating unit PS (also called the "hydraulic pressure generating device") uses an electric motor MT as its power source to generate front and rear wheel pressures Pwf, Pwr. The front and rear wheel pressures Pwf, Pwr are adjusted by a servo pressure Pc generated by the electric motor MT. Specifically, the hydraulic pressure generating unit PS and the servo chamber Ru of the apply unit AP are connected via a servo path HU (fluid path). The hydraulic pressure generating unit PS and the rear wheel cylinder CWr are connected via a rear wheel communication path HSR (fluid path). Furthermore, the hydraulic pressure generating unit PS is connected to the master reservoir RV via a supply path HH (fluid path) so that the brake fluid BF can be replenished when there is a shortage of brake fluid BF in the hydraulic pressure generating unit PS.

[0022] When the hydraulic pressure generating unit PS is operating (i.e., during braking), the supply path HH is cut off. This puts the hydraulic pressure generating unit PS and the master reservoir RV in a non-communicative state. In the front wheel braking system, the servo pressure Pc is supplied to the servo chamber Ru to generate a supply pressure Pm (master pressure). The supply pressure Pm generates a hydraulic pressure Pwf (front wheel pressure) in the front wheel cylinder CWf. Meanwhile, in the rear wheel braking system, the servo pressure Pc is directly supplied to the rear wheel cylinder CWr to generate a hydraulic pressure Pwr (rear wheel pressure) in the rear wheel cylinder CWr. The hydraulic pressure generating unit PS is provided with a servo pressure sensor PC to detect the servo pressure Pc. Details of the hydraulic pressure generating unit PS will be described later.

[0023] [Input unit NR] The input unit NR realizes regenerative cooperative control. "Regenerative cooperative control" cooperates hydraulic braking force Fp (braking force due to wheel pressure Pw) and regenerative braking force Fg (braking force due to regenerative generator GN) so that the kinetic energy of the vehicle can be efficiently recovered as electrical energy during braking. In regenerative cooperative control, the brake operating member BP is operated, but a state is created in which no wheel pressure Pw is generated. The input unit NR is composed of an input cylinder CN, an input piston NN, a first control valve VA, a second control valve VB, a stroke simulator SS, and an input pressure sensor PN.

[0024] The input cylinder CN is fixed to the master cylinder CM. An input piston NN is inserted into the input cylinder CN. The input piston NN is mechanically connected to a brake operating member BP (brake pedal) so as to move in conjunction with the movement of the brake operating member BP. There is a gap Ks (also called the "separation distance") between the end face of the input piston NN and the end face of the master piston NM. The separation distance Ks is adjusted by the servo pressure Pc, thereby achieving regenerative cooperative control.

[0025] The input chamber Rn of the input unit NR is connected to the reaction chamber Rs of the apply unit AP via an input path HN (fluid path). A normally closed first control valve VA is provided in the input path HN. The input path HN is connected to a master reservoir RV between the first control valve VA and the reaction chamber Rs via a reservoir path HR (fluid path). A normally open second control valve VB is provided in the reservoir path HR. An on-off type solenoid valve is used for the first and second control valves VA and VB. A stroke simulator SS is connected to the input path HN between the first control valve VA and the reaction chamber Rs.

[0026] When no power is supplied to the first and second control valves VA, VB, the first control valve VA is closed and the second control valve VB is open. When the first control valve VA is closed, the input chamber Rn is sealed and fluid locked. This causes the master piston NM to be displaced integrally with the brake operating member BP. When the second control valve VB is opened, the stroke simulator SS and the reaction chamber Rs are connected to the master reservoir RV.

[0027] When power is supplied (electricity is fed) to the first and second control valves VA, VB, the first control valve VA is opened and the second control valve VB is closed. This allows the master piston NM to be displaced separately from the brake operating member BP. At this time, the input chamber Rn is connected to the stroke simulator SS, so that the operating force of the brake operating member BP is generated by the stroke simulator SS. In order to detect the input pressure Pn, an input pressure sensor PN is provided in the input path HN between the input chamber Rn and the first control valve VA. The input pressure Pn is also the hydraulic pressure in the stroke simulator SS.

[0028] <First controller EA> The first actuator YA is controlled by a first controller EA. The first controller EA is composed of a microprocessor MP and a drive circuit DR. The first controller EA is connected to a communication bus BS so that signals (detection values, calculation values, control flags, etc.) can be shared between the first controller EA and other controllers (EB, EG, etc.).

[0029] The first controller EA directly receives various signals such as the operation displacement Sp (detection value of the operation displacement sensor SP), the input pressure Pn (detection value of the input pressure sensor PN), the servo pressure Pc (detection value of the servo pressure sensor PC), and the motor rotation angle Ka (detection value of the rotation angle sensor KA). Furthermore, the first controller EA receives various signals such as the supply pressure Pm and the limit regenerative braking force Fx from the communication bus BS. The first controller EA also outputs a target regenerative braking force Fh (target value of the regenerative braking force Fg) to the communication bus BS. The regenerative controller EG controls the regenerative braking force Fg (actual value) based on the target regenerative braking force Fh (target value) acquired from the communication bus BS.

[0030] An algorithm for pressure regulation control is programmed in the first controller EA (particularly, the microprocessor MP). The "pressure regulation control" is a control for adjusting the wheel pressure Pw (=Pwf, Pwr) and includes regenerative cooperative control. The pressure regulation control is executed based on the above-mentioned various signals (Sp, Pc, etc.). Based on the pressure regulation control algorithm, the drive circuit DR drives the electric motor MT and various solenoid valves (VA, etc.). The drive circuit DR includes an H-bridge circuit (also called an "inverter circuit") formed of switching elements (e.g., MOS-FET) to drive the electric motor MT. The drive circuit DR also includes switching elements to drive the various solenoid valves. In addition, the drive circuit DR includes a motor current sensor (not shown) that detects a supply current Im (also called a "motor current") to the electric motor MT. The electric motor MT is provided with a rotation angle sensor KA to detect a position Ka (rotation angle) of the motor shaft SM.

[0031] In the first controller EA, the drive signals Va, Vb of the first and second control valves VA, VB and the drive signal Mt of the electric motor MT are calculated. Then, the switching elements are driven in response to various drive signals (Mt, etc.). Specifically, in the control of the solenoid valve, power is supplied to the first and second control valves VA, VB based on the drive signals Va, Vb. As a result, the first control valve VA is opened and the second control valve VB is closed. In the control of the electric motor MT, a target pressure Pt is calculated based on the operation displacement Sp, etc. The "target pressure Pt" is a target value corresponding to the servo pressure Pc (actual value). Then, in the first controller EA, in response to the target pressure Pt and the drive signal Mt calculated based on the servo pressure Pc, the electric motor MT is controlled so that the servo pressure Pc (actual value) approaches and coincides with the target pressure Pt (target value).

[0032] <Second braking unit SB> A second brake unit SB is provided between the first brake unit SA and the wheel cylinder CW. The second brake unit SB executes antilock brake control, traction control, anti-skid control, etc. In the brake system related to the front wheels WHf (i.e., the front wheel connecting path HSf), a supply pressure Pm is supplied from the master cylinder CM to the second brake unit SB. On the other hand, in the brake system related to the rear wheels WHr (i.e., the rear wheel connecting path HSr), a servo pressure Pc is directly supplied from the hydraulic pressure generating unit PS to the second brake unit SB. In the second brake unit SB, the supply pressure Pm and the servo pressure Pc are adjusted (increased or decreased) and output as hydraulic pressures Pwf, Pwr (front and rear wheel pressures) of the front and rear wheel cylinders CWf, CWr. The configuration of the second brake unit SB is well known, so a description thereof will be omitted.

[0033] Normally, when the regenerative cooperative control is executed, the operation of the second actuator YB (electric motor, fluid pump, solenoid valve, etc.) is stopped. Therefore, the supply pressure Pm is outputted from the second braking unit SB as the front wheel pressure Pwf, and the servo pressure Pc is outputted as the rear wheel pressure Pwr.

[0034] <First embodiment of the hydraulic pressure generating unit PS> A first embodiment of the hydraulic pressure generating unit PS will be described with reference to the partial cross-sectional view of Fig. 2. In the hydraulic pressure generating unit PS (hydraulic pressure generating device), an electric motor MT is used as a pressure source (also called a "power source") to generate a servo pressure Pc. The wheel pressure Pw (=Pwf, Pwr) is adjusted by the servo pressure Pc.

[0035] <Shape and direction of movement of components> First, the directions related to the shapes, movements, etc. of the elements that make up the hydraulic pressure generating unit PS are defined. In the hydraulic pressure generating unit PS, the rotation axis Jm of the electric motor MT (particularly the motor shaft SM), the rotation axis Jk of the rotating member BK, the central axis Jn of the control piston NC, and the central axis Jc of the control cylinder CC are aligned in a straight line. The direction along (i.e., the parallel direction to) the axes Jm, Jk, Jn, and Jc is referred to as the "axial direction Hj." In contrast, the direction perpendicular to the axes Jm, Jk, Jn, and Jc is referred to as the "radial direction Hk." Therefore, the radial direction Hk is perpendicular to the axial direction Hj.

[0036] In a member (NC, BD, etc.) that is movable along the axial direction Hj, the direction approaching the bottom surface Mbc of the control cylinder CC is called the "forward direction Ha." Conversely, the direction moving away from the bottom surface Mbc of the control cylinder CC is called the "reverse direction Hb." Therefore, when the control piston NC is moved in the forward direction Ha, the volume of the control chamber Rc is decreased and its internal pressure Pc (servo pressure) is increased. In contrast, when the control piston NC is moved in the reverse direction Hb, the volume of the control chamber Rc is increased and the servo pressure Pc is decreased.

[0037] In the relationship between the rotational motion of the electric motor MT and the linear motion of the linear member BD (and thus the control piston NC), the forward rotation direction Hs of the electric motor MT corresponds to the forward direction Ha of the linear member BD. Therefore, the rotational motion of the electric motor MT in the reverse direction Hg corresponds to the backward direction Hb of the linear member BD. In other words, when the electric motor MT rotates in the forward rotation direction Hs, the linear member BD moves in the forward direction Ha. This reduces the volume of the control chamber Rc and increases the servo pressure Pc. Conversely, when the electric motor MT rotates in the reverse direction Hg, the linear member BD moves in the backward direction Hb. This increases the volume of the control chamber Rc and decreases the servo pressure Pc.

[0038] <Configuration of the hydraulic pressure generating unit PS> The hydraulic pressure generating unit PS is composed of a housing HG, an electric motor MT, a rotation angle sensor KA, a reducer GS, a conversion mechanism GH, a rotation stop member MD, and a control piston NC.

[0039] The housing HG holds the components (MT, GS, etc.) that make up the hydraulic pressure generating unit PS. The interior of the housing HG is separated into two spaces by a partition plate SK. One of the two spaces is a first storage chamber Ra (also simply referred to as the "first chamber"). The electric motor MT is stored in the first chamber Ra. The other of the two spaces is a second storage chamber Rb (also simply referred to as the "second chamber"). The reduction gear GS, conversion mechanism GH, etc. are stored in the second chamber Rb.

[0040] The housing HG is divided into multiple parts so that the components can be assembled. For example, the housing HG is divided into a cylinder housing HGc and a motor housing HGm. The motor housing HGm and the cylinder housing HGc are assembled together and ultimately integrated into the housing HG. In other words, the housing HG is a general term for the cylinder housing HGc and the motor housing HGm. In other words, the cylinder housing HGc and the motor housing HGm are parts of the housing HG.

[0041] Furthermore, the housing HG may be integrated with the first controller EA. Specifically, the first controller EA is composed of a control board on which the microprocessor MP and the drive circuit DR are mounted, and a controller housing (not shown) that houses the control board. The controller housing is then assembled and integrated with the housing HG. The housing HG (particularly, the cylinder housing HGc) holds the reducer GS and the conversion mechanism GH. The housing HG (particularly, the motor housing HGm) holds the electric motor MT.

[0042] A control cylinder CC (corresponding to a "cylinder") is formed in the housing HG (particularly, the cylinder housing HGc). A control piston NC (corresponding to a "piston") is inserted into the control cylinder CC. The control cylinder CC and the control piston NC form a control chamber Rc (hydraulic chamber). A discharge portion Au is provided in the control cylinder CC (particularly, the control chamber Rc). The discharge portion Au is connected to the servo path HU and the rear wheel communication path HSr. That is, the control chamber Rc is connected to the servo chamber Ru and the rear wheel cylinder CWr. As a result, the servo pressure Pc is supplied (output) to the servo chamber Ru and the rear wheel cylinder CWr.

[0043] The electric motor MT is a power source (pressurizing source) for generating the servo pressure Pc (hydraulic pressure in the control cylinder CC). Here, "power" refers to the energy required to move the movable members (BK, BD, etc.) in the hydraulic pressure generating unit PS. For example, power is defined as a physical quantity, namely, energy per unit time (also called "power"). The electric motor MT outputs a rotational power Tm (also called "first rotational power"). The rotational power Tm of the electric motor MT is obtained by multiplying the axial torque of the electric motor MT by the rotational speed of the electric motor MT (particularly, the motor shaft SM). The linear power Fn of the linearly moving member BD (described later) is obtained by multiplying the thrust of the linearly moving member BD (force acting in the axial direction Hj) by the linear speed of the linearly moving member BD (speed in the axial direction Hj).

[0044] A three-phase brushless motor is adopted as the electric motor MT. The electric motor MT is mounted in a motor housing HGm. The electric motor MT includes a motor coil CL, a motor shaft SM, and a rotation angle sensor KA. The motor coil CL (also simply referred to as a "coil (winding)") is fixed in the motor housing HGm. The motor coil CL is also referred to as a "stator." A motor line Lm is connected to the motor coil CL. Power is supplied to the motor coil CL from a first controller EA (particularly, a drive circuit DR) via the motor line Lm.

[0045] The motor shaft SM (also simply referred to as the "shaft") is rotatably supported relative to the motor housing HGm (i.e., the motor coil CL) by a bearing BB fixed within the motor housing HGm. A motor magnet Mm (permanent magnet) is fixed to the outer periphery of the shaft SM of the electric motor MT. For example, the motor magnet Mm is affixed to the motor shaft SM by adhesive or the like. The motor shaft SM is also referred to as the "rotor."

[0046] In the three-phase brushless motor MT, the magnetic pole position of the rotor SM (i.e., the rotation angle relative to the stator CL) is detected, and the current Im (motor current) flowing through the motor coil CL is switched. Here, the motor current Im is a general term for the currents flowing through the U phase, V phase, and W phase. The three-phase motor current Im relating to the U phase, V phase, and W phase is switched based on the rotation position Ka (also called the "rotation angle") of the motor shaft SM. In the first controller EA, the switching elements of the drive circuit DR (inverter circuit) are driven according to the rotation angle Ka. As a result, the motor current Im flowing through the motor coil CL is switched, and the electric motor MT is rotationally driven. Then, the rotational power Tm is output from the electric motor MT to the reducer GS.

[0047] A rotation angle sensor KA is provided on the electric motor MT (brushless motor) to detect a rotation angle Ka. The rotation angle sensor KA is composed of a sensor disk Ds, a sensor magnet Ms, a sensor board Kb, and a sensor wire Ls. The sensor disk Ds is fixed to the motor shaft SM to rotate integrally with the motor shaft SM. The sensor disk Ds is provided with a sensor magnet Ms. The sensor board Kb is fixed to the motor housing HGm. A hole is formed in the sensor board Kb so that the motor shaft SM passes through. A detection unit using a magnetic field detection element is provided around the hole to detect a change in the magnetic field generated when the motor shaft SM (i.e., the sensor magnet Ms) rotates. A signal detected by the magnetic field detection element is transmitted to the first controller EA (particularly, the microprocessor MP) by the sensor wire Ls.

[0048] The speed reducer GS reduces the speed of the first rotational power Tm output from the electric motor MT and outputs a second rotational power Tn. Specifically, the input shaft of the speed reducer GS and the motor shaft SM are fixed. Also, the output shaft of the speed reducer GS and the rotating member BK of the conversion mechanism GH are fixed. In the speed reducer GS, the speed input from the electric motor MT is reduced and the torque input from the electric motor MT is increased. Then, the second rotational power Tn is output from the speed reducer GS to the conversion mechanism GH.

[0049] For example, a planetary gear mechanism is used as the reducer GS. A "planetary gear mechanism" is a gear mechanism in which multiple planetary gears revolve around a sun gear while rotating on their own axes. The reducer GS is composed of a sun gear, planetary gears, an internal gear, and a planetary carrier. In a planetary gear mechanism, the planetary gears are supported by the planetary carrier, and orbital motion is extracted. For example, in the reducer GS, the internal gear (also called "inner gear") is fixed to the cylinder housing HGc. The sun gear (also called "sun gear") is fixed to the motor shaft SM, and a first rotational power Tm is input to the sun gear from the electric motor MT. Then, the planetary carrier of the reducer GS is fixed to a rotating member BK, and a second rotational power Tn is output from the planetary carrier to the conversion mechanism GH.

[0050] The conversion mechanism GH is composed of a rotating member BK that rotates and a linear motion member BD that moves linearly. In the conversion mechanism GH, a second rotational power Tn output from the reducer GS is input to the rotating member BK. The second rotational power Tn input to the rotating member BK is then converted into a linear power Fn of the linear motion member BD. The conversion mechanism GH is also called a "rotational-linear motion conversion mechanism."

[0051] For example, a "ball screw" is adopted as the conversion mechanism GH. Specifically, in the conversion mechanism GH, a rotating member BK, which is a shaft member, is fixed to the output shaft of the reducer GS. The rotating member BK is inserted into a linear motion member BD having a cylindrical shape. A ball screw groove Mzk is formed on the outer peripheral surface Mok of the rotating member BK. Similarly, a ball screw groove Mzd is also formed on the inner peripheral surface Mid of the linear motion member BD. A plurality of balls BL (steel balls) are fitted into the ball screw grooves Mzk and Mzd (see blow-out section XGH for the above).

[0052] In the conversion mechanism GH, the member having a screw groove on its outer circumferential surface is referred to as the "inner member." Also, the member having a screw groove on its inner circumferential surface is referred to as the "outer member." The outer member is disposed so as to cover the inner member, and the screw groove of the inner member and the screw groove of the outer member are meshed with each other. In detail, in the ball screw mechanism, the two screw grooves are meshed with each other via multiple balls BL.

[0053] In the ball screw mechanism employed as the conversion mechanism GH, a ball screw shaft (an inner member, also referred to as a "shaft member") is used as the rotating member BK, and a ball screw nut (an outer member, also referred to as a "nut member") is used as the linear motion member BD. In this configuration, a screw groove Mzk is formed on the outer circumferential surface Mok of the rotating member BK (inner member), and a screw groove Mzd is formed on the inner circumferential surface Mid of the linear motion member BD (outer member). The outer circumferential groove Mzk and the inner circumferential groove Mzd are engaged with each other via a ball BL.

[0054] A flange portion Fd is provided on the end of the linear motion member BD away from the control cylinder CC (particularly the control chamber Rc). The flange portion Fd is formed by extending the end of the cylindrical linear motion member BD in the radial direction Hk in a flange shape. A notch (an intentionally formed missing portion) is machined in the flange portion Fd. Here, the portion of the flange portion Fd where the notch is formed is referred to as the "fitting portion Kd."

[0055] The anti-rotation member MD is fixed to the cylinder housing HGc. For example, the anti-rotation member MD is a long and thin rod-shaped member (e.g., a pin member). The housing HG is provided with a plurality of holes Amd on the outer side of the linear motion member BD (i.e., on the side away from the rotation axis Jk with respect to the linear motion member BD). These holes Amd are opened in the axial direction Hj at equal intervals centered on the rotation axis Jk. The anti-rotation member MD is inserted into each of the plurality of holes Amd and fixed. A semicircular notch is provided in the flange portion Fd of the linear motion member BD. The notch (i.e., the fitting portion Kd) is engaged with the anti-rotation member MD, thereby preventing (restricting) the rotational movement of the linear motion member BD around the rotation axis Jk. As a result, when the rotating member BK is rotationally driven, the linear motion member BD moves along the axial direction Hj (forward direction Ha or backward direction Hb).

[0056] The control piston NC is inserted into a control cylinder CC formed in the cylinder housing HGc. More specifically, the control piston NC has a cylindrical shape with a bottom Btn. That is, the control piston NC is cup-shaped. The control piston NC is inserted into the control cylinder CC. Inside the control cylinder CC, a control chamber Rc (hydraulic chamber) is formed by the control piston NC (particularly, the bottom Btn).

[0057] The outer peripheral surface Mon of the control piston NC and the inner peripheral surface Mic of the control cylinder CC are sealed by two seal members SL1 and SL2. The first and second seal members SL1 and SL2 are fitted into first and second seal grooves Ms1 and Ms2 formed on the inner peripheral surface Mic of the control cylinder CC. Specifically, the first seal groove Ms1 is formed on the side farther from the bottom surface Mbc of the control cylinder CC. The first seal member SL1 is fixed to the first seal groove Ms1. Similarly, the second seal groove Ms2 is formed on the side closer to the bottom surface Mbc of the control cylinder CC, and the second seal member SL2 is fixed to the second seal groove Ms2. Between the two seal grooves Ms1 and Ms2, the cylinder housing HGc is provided with a hole (not shown, also referred to as a "housing hole") that penetrates the control cylinder CC. The housing hole is connected to the master reservoir RV via a supply path HH. The control piston NC is provided with a hole (not shown, also referred to as a "piston hole") that penetrates from the outer circumferential surface Mon to the bottom Btn so as to connect the housing hole and the control chamber Rc.

[0058] <Adjusting servo pressure Pc> In the brake control device SC, the wheel pressure Pw is adjusted by the servo pressure Pc which is the output of the hydraulic pressure generating unit PS. In the hydraulic pressure generating unit PS, the rotational power Tm (i.e., shaft torque) of the electric motor MT is converted by the conversion mechanism GH into a linear power Fn (i.e., thrust) of a linearly moving member BD (resulting in a control piston NC). Then, the control piston NC is moved by the linear power Fn, thereby generating and adjusting the servo pressure Pc. Note that the hydraulic pressure generating unit PS is provided with a servo pressure sensor PC to detect the servo pressure Pc.

[0059] The conversion mechanism GH is capable of both converting rotary motion into linear motion and converting linear motion into rotary motion. In the operation of the conversion mechanism GH, the former is called "positive operation" and the latter is called "negative operation." Therefore, the movement of the control piston NC is determined by the magnitude relationship between the torque output from the electric motor MT (also called "positive operation torque Qmt") and the torque input to the electric motor MT by the servo pressure Pc (also called "negative operation torque Qpc"). Adjustment (increase / decrease) of the servo pressure Pc will be explained below.

[0060] <Increase in servo pressure Pc> In Fig. 2, above the rotation axis Jk, a state in which the hydraulic pressure generating unit PS is not generating servo pressure Pc is shown. In this state, the control chamber Rc is connected to the master reservoir RV via the housing hole and the piston hole, and the servo pressure Pc is "0 (atmospheric pressure)." The positions of the linear motion member BD, the control piston NC, etc. in this state are referred to as the "initial position." In the initial position, the control piston NC is displaced to the maximum in the backward direction Hb, and the volume of the control chamber Rc is maximum.

[0061] When the braking demand value (a state quantity indicating a demand related to braking force, for example, the operation displacement Sp of the brake operating member BP) is increased, the target pressure Pt is increased from "0". The target pressure Pt is a target value corresponding to the servo pressure Pc (actual value). The target pressure Pt is increased as the braking demand value increases. As the target pressure Pt increases, the forward operating torque Qmt becomes larger than the reverse operating torque Qpc, and the electric motor MT rotates in the forward rotation direction Hs. In other words, the electric motor MT generates a rotational power Tm in the forward rotation direction Hs. The rotational power Tm is transmitted to the conversion mechanism GH via the reducer GS and is output as a linear power Fn of the linear moving member BD. Then, the control piston NC is pressed by the linear moving member BD. As a result, the control piston NC is moved in the forward direction Ha (the direction in which the volume of the control chamber Rc decreases).

[0062] This movement first blocks communication between the control chamber Rc and the master reservoir RV. When the control piston NC is further moved in the forward direction Ha, the servo pressure Pc (the internal pressure of the control chamber Rc) is increased from "0 (atmospheric pressure)". Brake fluid BF pressurized to the servo pressure Pc is output (pressurized) from the control chamber Rc of the control cylinder CC to the servo chamber Ru and the rear wheel cylinder CWr.

[0063] <Maintaining servo pressure Pc> When the braking demand value becomes constant, the target pressure Pt is maintained. The forward acting torque Qmt and the reverse acting torque Qpc become equal, and the electric motor MT stops rotating (i.e., the rotational speed of the electric motor MT becomes "0"). The movement of the control piston NC is stopped, and the servo pressure Pc is maintained constant (see the lower part of the rotation axis Jk in Figure 2).

[0064] <Decrease in servo pressure Pc> When the braking demand value is reduced, the target pressure Pt is reduced. This reduces the rotational power Tm of the electric motor MT. The reverse acting torque Qpc due to the servo pressure Pc becomes greater than the forward acting torque Qmt due to the electric motor MT, and the electric motor MT rotates in the reverse direction Hg. The control piston NC is moved in the backward direction Hb, and the volume of the control chamber Rc is increased. The brake fluid BF that had been moved to the servo chamber Ru and the rear wheel cylinder CWr is returned toward the control chamber Rc, so that the servo pressure Pc is reduced. As described above, in the hydraulic pressure generating unit PS, the control piston NC is moved along the rotation axis Jk by the linear power Fn, and the servo pressure Pc of the control cylinder CC is adjusted (increased, maintained, decreased).

[0065] <Fixing the anti-rotation member MD to the housing HG> A method of fixing the anti-rotation member MD to the housing HG (e.g., cylinder housing HGc) will be described with reference to the partial cross-sectional view of FIG. 3. FIG. 3(a) shows a structure adopted in the hydraulic pressure generating unit PS. FIG. 3(b) shows a structure adopted in the prior art (e.g., U.S. Patent Application Publication No. 2021 / 0122342).

[0066] A pin member is adopted as the anti-rotation member MD. The housing HG is provided with a hole Amd (also called a "mounting hole") and a groove Mmd (also called a "mounting groove") for mounting the anti-rotation member MD. For example, a surface Mm (also called a "fixing surface") perpendicular to the rotation axis Jk is formed inside the housing HG (particularly, inside the second chamber Rb). The mounting hole Amd is drilled perpendicular to the fixing surface Mm. Therefore, the mounting hole Amd is parallel to the rotation axis Jk (i.e., the axial direction Hj). Furthermore, a semicylindrical mounting groove Mmd is formed so as to be continuous with the mounting hole Amd. In detail, the mounting groove Mmd is connected to the mounting hole Amd and is dug in a shape of a continuous semicircle (i.e., a semicylindrical shape, also called a "half-moon shape") parallel to the rotation axis Jk (i.e., the axial direction Hj).

[0067] The anti-rotation member MD is fixed by being pressed into the mounting hole Amd while being fitted into the mounting groove Mmd. The portion of the anti-rotation member MD that protrudes from the mounting groove Mmd (referred to as the "guide portion") is engaged with the fitting portion Kd. The fitting portion Kd slides along the guide portion, thereby preventing the linear motion member BD from rotating around the rotation axis Jk.

[0068] The inner peripheral surface Mic of the control cylinder CC is provided with first and second seal grooves Ms1 and Ms2. The first and second seal members SL1 and SL2 are fitted into the first and second seal grooves Ms1 and Ms2. The first and second seal members SL1 and SL2 seal the inner peripheral surface Mic of the control cylinder CC and the outer peripheral surface Mon of the control piston NC. Here, the first seal groove Ms1 and the first seal member SL1 are disposed on the side farther from (distant from) the bottom surface Mbc of the control cylinder CC, and the second seal groove Ms2 and the second seal member SL2 are disposed on the side closer to the bottom surface Mbc.

[0069] With reference to FIG. 3(a), the positional relationship between the mounting hole Amd and the first seal groove Ms1 employed in the hydraulic pressure generating unit PS will be described. In the hydraulic pressure generating unit PS, the mounting hole Amd of the rotation prevention member MD overlaps with the first seal groove Ms1 to which the first seal member SL1 is attached in the direction along the rotation axis Jk. This structure is called an "overlap structure." In detail, in the overlap structure, as shown in the blowing portion ZMa, when parallel projection is performed in a direction perpendicular to the rotation axis Jk (i.e., the radial direction Hk), the image Zam (projection) of the mounting hole Amd projected on the projection plane ME and the image Zms (projection) of the first seal groove Ms1 projected on the projection plane ME have an overlapping portion. In other words, in the overlap structure employed by the hydraulic pressure generating unit PS, the mounting hole Amd exists in a cross section perpendicular to the rotation axis Jk, including the first seal groove Ms1 (see the AA cross section). Note that "projection" refers to the shadow of an object being projected onto a flat surface, or the projected image (shadow).

[0070] With reference to Fig. 3(b), the positional relationship between the mounting hole Amd and the first seal groove Ms1 employed in the above-mentioned conventional technology will be described. In the conventional technology, the mounting hole Amd of the anti-rotation member MD and the first seal groove Ms1 to which the first seal member SL1 is attached do not overlap. Therefore, in a parallel projection in the radial direction Hk, the projection Zam of the mounting hole Amd and the projection Zms of the first seal groove Ms1 do not overlap. In other words, the mounting hole Amd does not exist in a cross section perpendicular to the rotation axis Jk, including the first seal groove Ms1 (see the cross section BB).

[0071] By adopting an overlap structure, the hydraulic pressure generating unit PS can reduce the dimension in the axial direction Hj (also called the "axial length"). The mounting hole Amd for fixing the anti-rotation member MD requires a certain length Lz (hole depth). The flange portion Fd of the linear motion member BD fits into and slides on the guide portion (the portion protruding from the mounting groove Mmd) of the anti-rotation member MD. The guide portion is the portion of the anti-rotation member MD that is not inserted into the mounting hole Amd, and corresponds to the mounting groove Mmd. The length of the guide portion (i.e., the mounting groove Mmd) in the axial direction Hj must be greater than or equal to the maximum displacement of the control piston NC.

[0072] For example, if the overlap structure is not adopted, the mounting groove Mmd needs to be separated from the first seal groove Ms1 by at least the length Lz of the mounting hole Amd. Therefore, in the hydraulic pressure generating unit PS, the mounting hole Amd is arranged to overlap the first seal groove Ms1 when viewed in the radial direction Hk. By adopting the overlap structure in the hydraulic pressure generating unit PS, the length Lz (depth) required for the mounting hole Amd can be saved, so that the device can be made more compact (i.e., the axial length can be shortened). Note that, although the axial length is shortened when the overlap structure is adopted, this is disadvantageous in terms of the dimensions in the radial direction Hk. However, in the hydraulic pressure generating unit PS, the rotation axis Jm of the electric motor MT and the rotation axis Jk of the rotating member BK are on a straight line, so there is a dimensional margin in the radial direction Hk. Therefore, shortening the axial length has a higher priority than making the device more compact in the radial direction Hk.

[0073] <Second embodiment of the hydraulic pressure generating unit PS> A second embodiment of the hydraulic pressure generating unit PS will be described with reference to the partial cross-sectional view of FIG. 4. In the first embodiment, the linear motion member BD was prevented from rotating by fitting a notch (i.e., a first fitting portion Kd) formed in a flange portion Fd (also referred to as a "first flange portion") of the linear motion member BD to a rotation prevention member MD (particularly, a guide portion that is not inserted into the mounting hole Amd and protrudes from the mounting groove Mmd). In the second embodiment, a flange portion Fe (also referred to as a "second flange portion") is provided at an end of the control piston NC, and a fitting portion Ke in which a notch is machined is provided in the flange portion Fe. The fitting portion Ke (second fitting portion) is engaged with a guide portion of the rotation prevention member MD. The following mainly describes the differences. The shapes of the components and the directions of movement are the same as those in the first embodiment.

[0074] In the second embodiment, as in the first embodiment, a ball screw mechanism is used for the conversion mechanism GH. In the conversion mechanism GH, a linear motion member BD (ball screw nut) which is an outer member is arranged to cover a rotating member BK (ball screw shaft) which is an inner member, and the respective screw grooves Mzk, Mzd are engaged with each other via a ball BL. A control piston NC is fixed to the linear motion member BD and can move integrally therewith.

[0075] In the second embodiment, a flange portion Fe is provided at the end of the control piston NC farther from the bottom surface Mbc of the control cylinder CC. As with the flange portion Fd in the first embodiment, the end of the cylindrical control piston NC is extended in the radial direction Hk in a flange shape at the flange portion Fe. The flange portion Fe has a fitting portion Ke (a portion provided with a notch). The anti-rotation member MD is fixed to the housing HG by the above-mentioned overlap structure. The fitting portion Ke of the flange portion Fe is engaged with the guide portion (a portion not inserted into the mounting hole Amd and protruding from the mounting groove Mmd) of the anti-rotation member MD. The fitting portion Ke slides along the guide portion. This limits the rotational motion of the control piston NC (and thus the linear motion member BD).

[0076] <Third embodiment of the hydraulic pressure generating unit PS> A third embodiment of the hydraulic pressure generating unit PS will be described with reference to the partial cross-sectional view of FIG. 5. In the first and second embodiments, in the conversion mechanism GH, the linear motion member BD is used as the outer member, and the rotating member BK is used as the inner member. Conversely, in the third embodiment, the outer member (nut member) is the rotating member BK, and the inner member (shaft member) is the linear motion member BD. The following mainly describes the differences from the first and second embodiments. Note that the shapes of the components and the directions of motion are the same as in the first and second embodiments.

[0077] In the third embodiment, as in the first and second embodiments, a ball screw mechanism is used for the conversion mechanism GH. In the conversion mechanism GH according to the third embodiment, a linear motion member BD, which is a ball screw shaft, and a rotating member BK, which is a ball screw nut, are engaged with each other via balls BL. In the third embodiment, the control piston NC is fixed to the linear motion member BD and can move integrally therewith.

[0078] In the third embodiment, similarly to the second embodiment, a flange portion Fe (second flange portion) is provided at the end of the control piston NC (the side farther from the bottom surface Mbc of the control cylinder CC). At the flange portion Fe, the end of the cylindrical control piston NC is extended in the radial direction Hk in a flange shape. The flange portion Fe is provided with a fitting portion Ke (second fitting portion) having a notch so as to engage with the anti-rotation member MD. The anti-rotation member MD is fixed to the housing HG by the above-mentioned overlap structure (i.e., a structure in which the projection Zms of the seal groove Ms1 of the first seal member SL1 and the projection Zam of the mounting hole Amd of the anti-rotation member MD overlap). The fitting portion Ke slides along the guide portion of the anti-rotation member MD, thereby restricting the rotational motion of the control piston NC (as a result, the linear motion member BD).

[0079] <Other embodiments of the hydraulic pressure generating unit PS> Other embodiments of the hydraulic pressure generating unit PS will be described below. In the other embodiments, the hydraulic pressure generating unit PS also provides the same effects as those described above (such as shortening the axial dimension due to the overlap structure).

[0080] In the embodiment of the hydraulic pressure generating unit PS described above, a ball screw is used as the conversion mechanism GH. Alternatively, a sliding screw (e.g., a trapezoidal screw) may be used as the conversion mechanism GH. In a configuration in which a sliding screw mechanism is used, a male thread is formed as a screw groove on the inner member. Also, a female thread is formed as a screw groove on the outer member. The male thread and the female thread are directly engaged with each other. Reverse operation occurs even in a conversion mechanism GH in which a sliding screw is used.

[0081] In the embodiment of the hydraulic pressure generating unit PS described above, a configuration is adopted in which the axis Jm and the axes Jc, Jn, and Jk are aligned in a straight line. This configuration is called a "coaxial configuration (or single-shaft configuration)" because the axis Jm and the axis Jc, etc. are coaxial. In the coaxial configuration, a reducer GS in which the rotation axis of the input shaft and the rotation axis of the output shaft are coaxial (for example, a planetary gear mechanism) is used. Instead of this configuration, a "separate-shaft configuration (or two-shaft configuration)" in which the axis Jm and the axis Jc, Jn, and Jk are on different axes may be used. In the separate-shaft configuration, a reducer GS in which the rotation axis of the input shaft and the rotation axis of the output shaft are different (for example, a gear train) is used. In the separate-shaft configuration, the axis Jm and the axis Jc, Jn, and Jk are separate axes but are arranged in parallel. Even in the separate shaft configuration, the axes Jc, Jn, and Jk are in a straight line. However, as described above, in the coaxial configuration, it is more desirable to shorten the shaft length, so the overlap structure is very effective.

[0082] In the embodiment of the hydraulic pressure generating unit PS described above, the mounting hole Amd overlaps with the first seal groove Ms1. Alternatively, the mounting hole Amd may overlap with both the first and second seal grooves Ms1, Ms2. That is, the housing HG of the hydraulic pressure generating unit PS is formed with two seal grooves Ms1, Ms2, and the mounting hole Amd is machined so as to overlap with at least the first seal groove Ms1 (the side farther from the bottom surface Mbc).

[0083] In the embodiment of the hydraulic pressure generating unit PS described above, two seal members SL1 and SL2 are used to seal the control piston NC and the control cylinder CC. Alternatively, in the hydraulic pressure generating unit PS, the second seal member SL2 may be omitted and sealing may be performed by one seal member SL1. Even in this configuration, the mounting hole Amd overlaps the seal groove Ms1 that holds the seal member SL1.

[0084] The above-mentioned braking control device SC is applied to a vehicle in which the front wheels WHf are provided with a regenerative device KG and in which regenerative cooperative control is executed. In a vehicle in which regenerative cooperative control is executed, the regenerative device KG may be provided in at least one of the front wheels WHf and the rear wheels WHr. The braking control device SC may also be applied to a vehicle in which the regenerative device KG is power-saving and in which regenerative cooperative control is not executed. In other words, the braking control device SC may be applied to various vehicles, regardless of whether or not regenerative cooperative control is executed.

[0085] In the above-mentioned example of the configuration of the brake control device SC, a single-type master cylinder CM is used. A tandem-type master cylinder CM may be used in the brake control device SC. In this configuration, two master chambers Rm are formed inside the CM. Then, the servo pressure Pc is supplied from the hydraulic pressure generating unit PS to the servo chamber Ru, and the wheel pressure Pw is supplied from the master chamber Rm to the wheel cylinder CW. In this configuration, the brake control device SC may adopt not only a front-rear type but also a diagonal type (also called "X type") as the two-system brake system. In the diagonal type brake control device SC, one of the two master chambers Rm is connected to the right front wheel cylinder and the left rear wheel cylinder. Also, the other of the two master chambers Rm is connected to the left front wheel cylinder and the right rear wheel cylinder.

[0086] In the above-mentioned configuration example of the brake control device SC, in the first brake unit SA, the supply pressure Pm is outputted via the master cylinder CM. That is, the apply unit AP and the hydraulic pressure generating unit PS are arranged in series in the hydraulic pressure transmission path, and the servo pressure Pc supplied from the hydraulic pressure generating unit PS is transmitted as the supply pressure Pm via the master piston NM. Alternatively, the apply unit AP and the hydraulic pressure generating unit PS may be arranged in parallel. Specifically, the apply unit AP (particularly, the master cylinder CM) and the hydraulic pressure generating unit PS are each directly connected to the second actuator YB. Then, either one of "connection between the hydraulic pressure generating unit PS and the second actuator YB" and "connection between the apply unit AP and the second actuator YB" is selected by an on-off solenoid valve (referred to as a "switching valve"). When the former is selected, the servo pressure Pc generated in the hydraulic pressure generating unit PS is directly outputted as the supply pressure Pm without passing through the apply unit AP. At this time, the apply unit AP is connected to the stroke simulator SS, and the operating force of the brake operating member BP is generated by the stroke simulator SS. On the other hand, when the latter is selected, the hydraulic pressure in the master chamber Rm generated by the operation of the brake operating member BP is output as the supply pressure Pm. At this time, the apply unit AP is disconnected from the stroke simulator SS.

[0087] In the above-mentioned example of the configuration of the brake control device SC, in the apply unit AP, the pressure receiving area rm (master area) of the master chamber Rm and the pressure receiving area ru (servo area) of the servo chamber Ru are set to be equal. The master area rm and the servo area ru do not have to be equal. In a configuration in which the master area rm and the servo area ru are different, it is possible to perform a conversion calculation between the supply pressure Pm (master pressure) and the servo pressure Pc based on the ratio between the servo area ru and the master area rm (i.e., conversion based on "Pm·rm=Pc·ru").

[0088] <Summary of the embodiment> The following summarizes an embodiment of the hydraulic pressure generating unit PS (hydraulic pressure generating device): The hydraulic pressure generating unit PS is applied to a brake control device SC that adjusts the wheel pressure Pw of the wheel cylinder CW to control the braking force of the wheel WH.

[0089] The hydraulic pressure generating unit PS includes a housing HG, an electric motor MT, a conversion mechanism GH, a control piston NC (corresponding to a "piston"), a seal member SL1, and a rotation-stop member MD. The housing HG holds the conversion mechanism GH and the like. A control cylinder CC (corresponding to a "cylinder") is formed in the housing HG. A rotational power Tm is output by the electric motor MT. The rotational power Tm input to the rotating member BK is output as a linear power Fn of the linearly moving member BD by the conversion mechanism GH. The control piston NC is inserted into the control cylinder CC, and increases the hydraulic pressure Pc of the control cylinder CC by moving in the forward direction Ha (the direction approaching the bottom surface Mbc of the control cylinder CC) by the linear power Fn. The seal member SL1 is fixed (held) in a seal groove Ms1 provided in the housing HG, and seals the control cylinder CC (particularly, the inner peripheral surface Mic) and the control piston NC (particularly, the outer peripheral surface Mon). The anti-rotation member MD is fixed to the housing HG and prevents (restricts) the linear motion member BD from rotating around the rotation axis Jk of the rotating member BK. Here, the anti-rotation member MD is fixed to a mounting hole Amd provided in the housing HG.

[0090] When the hydraulic pressure generating unit PS is projected in a direction perpendicular to the rotation axis Jk (i.e., in the radial direction Hk), a projection (image) Zms of the seal groove Ms1 that fixes the seal member SL1 overlaps with a portion of the projection (image) Zam of the hole Amd (mounting hole) that fixes the anti-rotation member MD. In other words, the mounting hole Amd exists in a cross section in the radial direction Hk that includes the seal groove Ms1. A certain length is required for the mounting hole Amd to fix the anti-rotation member MD, but by employing an overlap structure, the length required for the mounting hole Amd in terms of the axial length can be shortened. As a result, the hydraulic pressure generating unit PS can be made more compact.

[0091] In the hydraulic pressure generating unit PS, a fitting portion Kd (first fitting portion) having a notch is provided on a linear motion member BD. The fitting portion Kd is engaged with a rotation prevention member MD to restrict rotation of the linear motion member BD (i.e., to prevent rotation). Alternatively, a control piston NC is fixed to the linear motion member BD, and a fitting portion Ke (second fitting portion) having a notch is provided on the control piston NC. The fitting portion Ke is engaged with the rotation prevention member MD to prevent rotation.

[0092] For example, a pin member with a circular cross section is used for the anti-rotation member MD. A plurality of circular mounting holes Amd are formed in the housing HG along the rotation axis Jk. Here, the plurality of mounting holes Amd are formed at equal intervals around the rotation axis Jk. The plurality of anti-rotation members MD are fixed by inserting a anti-rotation member MD (pin member) into each of the mounting holes Amd. A fitting portion Kd (or a fitting portion Ke) having a semicircular notch formed therein is provided on the flange portion Fd of the linear motion member BD (or the flange portion Fe of the control piston NC). The fitting portion Kd (or the fitting portion Ke) and the anti-rotation member MD (particularly, the guide portion not inserted into the mounting hole Amd) engage with each other, thereby restraining (restricting) the rotational motion of the linear motion member BD.

[0093] The anti-rotation member MD may be a key member having a square cross section. In a configuration in which a key member is used, the mounting hole Amd is a square hole. The fitting portion Kd (or the fitting portion Ke) is machined with a square notch that can fit the anti-rotation member MD (key member). [Explanation of symbols]

[0094] SC...Brake control device, SX...Brake device, BP...Brake operating member (brake pedal), BF...Brake fluid (hydraulic fluid), SA, SB...First and second brake units, YA, YB...First and second actuators, EA, EB...First and second controllers, BS...Communication bus, CM...Master cylinder, CW...Wheel cylinder, AP...Apply unit, NR...Input unit, PS...Hydraulic pressure generating unit (hydraulic pressure generator), MT...Electric motor, VA, VB...First and second control valves, SP...Operation Displacement sensor, Sp...operation displacement (detection value of SP), PC...servo pressure sensor, Pc...servo pressure (internal pressure of Rc, detected value of PC), Pm...supply pressure (internal pressure of Rm), Pwf, Pwr...front and rear wheel pressure, HG...housing (generic term for HGm and HGc), HGm...motor housing (part of HG), HGc...cylinder housing (part of HG), GS...reduction gear, GH...conversion mechanism, BK...rotating member, BD...linear member, NC...control piston, CC...control cylinder, MD... Anti-rotation member, Rc...control chamber (hydraulic chamber of CC), Fd...flange of BD, Kd...fitting part of Fd (first fitting part), Fe...flange of NC, Ke...fitting part of Fe (second fitting part), Tm...first rotational power (output from MT and input to GS), Tn...second rotational power (output from GS and input to BK), Fn...linear power (output of BD), Jm...rotational axis of MT, Jk...rotational axis of BK, Jn...central axis of NC, Jc...central axis of CC, Amd...mounting hole (MD to HG), Mmd...mounting groove (groove for fixing MD to HG), SL1, SL2...first and second seal members, Zs1, Zs2...first and second seal grooves (grooves for mounting SL1, SL2 to HG), ME...projection surface (plane on which the shadow is cast when projected parallel to Hk), Zam...projection of Amd (shadow of Amd projected onto ME), Zms...projection of Zs1 (shadow of Zs1 projected onto ME), Mm...fixing surface (inner surface of Rb on which Amd is formed).

Claims

1. an electric motor that outputs rotational power; a conversion mechanism that converts the rotational power input to a rotation member into linear power for a linearly moving member; a piston inserted into the cylinder and moving by the linear power to increase the hydraulic pressure in the cylinder; a housing in which the cylinder is formed and which holds a seal member that seals the cylinder and the piston; a rotation preventing member fixed to the housing and configured to prevent the linear motion member from rotating about a rotation axis of the rotation member; In a hydraulic pressure generating device comprising: a projection of a seal groove for fixing the seal member and a projection of a hole for fixing the anti-rotation member partially overlap with each other when projected parallel to a direction perpendicular to the rotation axis.

2. 2. The hydraulic pressure generating device according to claim 1, A hydraulic pressure generating device in which the linear motion member has a notch, and the blocking is performed by engaging the notch with the anti-rotation member.

3. 2. The hydraulic pressure generating device according to claim 1, The piston has a notch and is fixed to the linear motion member, and the prevention is performed by engaging the notch with the anti-rotation member.

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