Brake control device for vehicle

Abstract

To provide an integrated type brake control device that can efficiently carry out inspection.SOLUTION: A brake control device comprises: a main housing HGc which has first and second cylinders CC formed; a first piston which is inserted into the first cylinder, and can move together with a brake operation member to generate supply pressure Pm in the first cylinder; an electric motor MT which generates first rotary power Tm; a speed reducer GS which reduces the first rotary power Tm and output second rotary power Tn; a conversion mechanism GH which converts the second rotary power Tn into linear power Fn; a second piston which is inserted into the second cylinder CC, and moves with the linear power Fn to generate servo pressure Pc in the second cylinder CC; and a sub-housing HGs which holds the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the second piston, and is assembled in the main housing HGc.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a braking control device for a vehicle. [Background technology]

[0002] Patent Document 1 describes that in order to reduce the size of the brake fluid pressure supply unit, "the brake fluid pressure supply unit 10 is equipped with a linear motion conversion mechanism 14 that converts the rotational motion of the rotating shaft 112 of the electric motor 11 into linear motion of a ball screw 141 as a linear motion part, and moves the piston 122 by the ball screw 141, and a power transmission part 15 that includes a drive gear 151 that rotates together with the rotating shaft 112 and transmits the rotational motion of the rotating shaft 112 to the linear motion conversion mechanism 14, the rotating shaft 112 extending from the main body 111 of the electric motor 11 towards the housing 13, and the drive gear 151 being disposed between the main body 111 of the electric motor 11 and the housing 13."

[0003] Incidentally, the upstream unit U1 (also referred to as the "brake control device") in Patent Document 1 is configured as a single unit. This type of configuration is referred to as an "integrated type." In an integrated brake control device, a plurality of cylinder holes are formed in the housing, such as the master cylinder 17, the cylinder 121 for the electric cylinder device 12, and a cylinder for the simulator SS. A piston is assembled in each of these cylinder holes via a seal member. Furthermore, components such as an electromagnetic valve are assembled to complete the integrated brake control device. A large number of components are assembled in the integrated brake control device, and it is preferable that these components be inspected efficiently. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-056252 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above problems, an object of the present invention is to provide an integrated brake control device that can be efficiently inspected. [Means for solving the problem]

[0006] The vehicle brake control device (SA) of the present invention comprises a main housing (HGc) in which first and second cylinders (CM, CC) are formed, a first piston (NM) inserted into the first cylinder (CM) and capable of generating a supply pressure (Pm) in the first cylinder (CM) by moving in conjunction with a brake operating member (BP), an electric motor (MT) that generates a first rotational power (Tm), a reduction gear (GS) that reduces the speed of the first rotational power (Tm) and outputs a second rotational power (Tn), a conversion mechanism (GH) that converts the second rotational power (Tn) into a linear power (Fn), a second piston (NC) inserted into the second cylinder (CC) and moves by the linear power (Fn) to generate a servo pressure (Pc) in the second cylinder (CC), and a sub-housing (HGs) that holds the electric motor (MT), the reduction gear (GS), the conversion mechanism (GH), and the second piston (NC) and is assembled to the main housing (HGc).

[0007] In the vehicle brake control device (SA) according to the present invention, the sub-housing (HGs) includes a gear housing (HGg) that fixes a bearing (BC) that supports the conversion mechanism (GH), and when projected parallel to a direction (Hk) perpendicular to the rotation axis (Jk) of the bearing (BC), the projection of the bearing (BC) overlaps with the projection of the gear housing (HGg), but the projection of the second piston (NC) does not overlap with the projection of the gear housing (HGg). The sub-housing (HGs) also includes a motor housing (HGm) that supports the electric motor (MT), and the motor housing (HGm) and the gear housing (HGg) are fastened together to the main housing (HGc). According to the above configuration, a unit inspection of the sub-assembly SY can be easily performed. As a result, the inspection efficiency of the brake control device SA can be improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram for explaining an embodiment of a brake control device SA. [Diagram 2] 4 is a partial cross-sectional view for explaining the configuration of a liquid pressure generating unit PS. FIG. [Diagram 3] FIG. 13 is a schematic diagram for explaining the assembly of a subassembly SY. [Figure 4] FIG. 13 is a schematic diagram for explaining a first unit inspection example of the subassembly SY. [Diagram 5] FIG. 13 is a schematic diagram for explaining a second unit inspection example of the subassembly SY. 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 actuator YA of the brake control device SA, the actuator YB of the modulator device SB, and the wheel cylinder CW are connected by a fluid path (communication path HS). Furthermore, in the 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 a flow path within the actuator (for example, a flow path within the main housing HGc), piping, 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 SA> An embodiment of the brake control device SA will be described with reference to the schematic diagram of Fig. 1. For example, the brake control device SA 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. That is, the regenerative device KG can generate the regenerative braking force Fg. For example, the regenerative device KG is provided on the front wheels WHf, and the 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). The 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. This applies 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 provided with a brake operating member BP and various sensors (SP, etc.). The brake operating member BP (for example, 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, and in a brake-by-wire type brake control device SA, it is a signal that indicates the driver's braking intention (i.e., a braking command). 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] A vehicle is provided with various sensors for braking control, such as anti-lock brake control and anti-skid control, which individually controls the wheel pressure Pw of each wheel WH. Specifically, each wheel WH is provided with a wheel speed sensor VW that detects its rotational speed Vw (referred to as "wheel speed"). In addition, a steering amount sensor that detects a steering amount Sa (e.g., an operation angle) of a steering operation member (e.g., a steering wheel), a yaw rate sensor that detects a yaw rate Yr of the vehicle, a longitudinal acceleration sensor that detects a longitudinal acceleration Gx (also referred to as "deceleration") of the vehicle, and a lateral acceleration sensor that detects a lateral acceleration Gy of the vehicle are provided (all not shown).

[0016] <Brake control device SA> The vehicle is equipped with a brake control device SA. The brake control device SA employs a so-called front and rear type (also called "type II") brake system as the two-system brake system. The brake control device 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 the brake operating member BP (brake pedal). The brake control device SA is composed of an actuator YA and a controller EA. The actuator YA and controller EA are integrated in the brake control device SA. The brake control device SA adjusts the actual wheel pressure Pw of each wheel cylinder CW.

[0017] <YA actuator> The actuator YA is controlled by a controller EA. The actuator YA is composed of an apply unit AP, a hydraulic pressure generating unit PS, and an input unit NR. Each unit (AP, etc.) is formed in or assembled to the main housing HGc.

[0018] [Apply Unit AP] The apply unit AP is mounted to the main housing HGc. A supply pressure Pm can be output from the apply unit AP in response to operation of the brake operating member BP. The apply unit AP is composed of a single-type master cylinder CM and a master piston NM.

[0019] A single type master cylinder CM (i.e., a cylindrical hole, equivalent to a "first cylinder") is formed in the main housing HGc. 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 divided by one side 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. In other words, the master chamber Rm and the servo chamber Ru are arranged to face each other with the flange portion Tu in between. 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 is mounted in the main housing HGc. The hydraulic pressure generating unit PS generates a servo pressure Pc using an electric motor MT as a power source. 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). Therefore, the front and rear wheel pressures Pwf and Pwr are adjusted by the hydraulic pressure generating unit PS. 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 is replenished when the brake fluid BF is insufficient.

[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 is mounted to the main housing HGc. 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] An input cylinder CN (a cylindrical hole similar to that of the master cylinder CM) is formed in the main housing HGc. 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) via a clevis (U-shaped link) 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. Regenerative cooperative control is achieved by adjusting the separation distance Ks by the servo pressure Pc.

[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 passage HN (a fluid passage formed in the main housing HGc). A normally closed first control valve VA is provided in the input passage HN. The input passage HN is connected to a master reservoir RV between the first control valve VA and the reaction chamber Rs via a reservoir passage HR (a fluid passage formed in the main housing HGc). A normally open second control valve VB is provided in the reservoir passage HR. That is, the first and second control valves VA and VB are assembled to the main housing HGc. A stroke simulator SS is connected to the input passage HN between the first control valve VA and the reaction chamber Rs.

[0026] The first and second control valves VA and VB are solenoid valves of the on-off type. When no power is supplied to the first and second control valves VA and VB, the first control valve VA is closed and the second control valve VB is opened. When the first control valve VA is closed, the input chamber Rn is sealed and fluid-locked. As a result, the master piston NM is displaced integrally with the brake operating member BP. When the second control valve VB is opened, the stroke simulator SS and the reaction force chamber Rs are communicated with the master reservoir RV. On the other hand, when power is supplied to the first and second control valves VA and VB, the first control valve VA is opened and the second control valve VB is closed. As a result, the master piston NM can 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.

[0027] The stroke simulator SS is assembled to the main housing HGc. Specifically, a simulator cylinder is formed in the main housing HGc. The simulator cylinder is provided with a simulator piston and an elastic body (e.g., a compression spring) (not shown). When brake fluid BF is moved into the stroke simulator SS, the simulator piston is pushed by the inflowing brake fluid BF. A force is applied to the simulator piston by the elastic body in a direction that blocks the inflow of brake fluid BF, so that when the brake operating member BP is operated, an operating force corresponding to the operating displacement Sp is generated.

[0028] An input pressure sensor PN is provided in the input passage HN between the input chamber Rn and the first control valve VA to detect the input pressure Pn. The input pressure Pn is also the hydraulic pressure in the stroke simulator SS.

[0029] When power cannot be supplied to the components (MT, VA, VB, etc.) of the brake control device SA (i.e., when the power supply fails), the input chamber Rn is sealed and the master piston NM is displaced together with the brake operating member BP. This state is called "manual mode." In manual mode, the master piston NM moves in conjunction with the movement of the brake operating member BP. In other words, the front wheel pressure Pwf is generated and adjusted by the supply pressure Pm generated only by the driver's muscle force.

[0030] When power can be supplied to the components (MT, VA, VB, etc.) of the brake control device SA (i.e., when the power supply is normal), the master piston NM and the brake operating member BP can be displaced separately. This state is called "by-wire mode." In the by-wire mode, the front and rear wheel pressures Pwf, Pwr are generated and adjusted by the servo pressure Pc from the hydraulic pressure generating unit PS. In other words, the brake control device SA takes fail-safe into consideration, and the hydraulic pressure Pw in the wheel cylinder CW is generated by either the supply pressure Pm powered by the operating force of the brake operating member BP, or the servo pressure Pc powered by the electric motor MT.

[0031] <Controller EA> The actuator YA is controlled by a controller EA. The controller EA is housed in a controller housing HGe. The controller housing HGe is attached to the main housing HGc. The controller EA is composed of a microprocessor MP and a drive circuit DR. The controller EA is connected to a communication bus BS so that signals (detection values, calculation values, control flags, etc.) can be shared between the controllers EB, EG, etc.

[0032] The 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). In addition, the controller EA receives various signals such as the supply pressure Pm and the limit regenerative braking force Fx from the communication bus BS. The 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.

[0033] The controller EA (particularly the microprocessor MP) is programmed with a pressure regulation control algorithm. "Pressure regulation control" is a control for adjusting the wheel pressure Pw (=Pwf, Pwr) and includes regenerative cooperative control. Pressure regulation control is performed based on the various signals (Sp, Pc, etc.) mentioned above.

[0034] The electric motor MT and various solenoid valves (VA, etc.) are driven by the drive circuit DR based on the voltage regulation control algorithm. In the drive circuit DR, an H-bridge circuit (also called an "inverter circuit") is formed with switching elements (e.g., MOS-FET) to drive the electric motor MT. The drive circuit DR is also provided with switching elements to drive the various solenoid valves. In addition, the drive circuit DR includes a motor current sensor (not shown) that detects the supply current Im (also called the "motor current") to the electric motor MT. The electric motor MT is provided with a rotation angle sensor KA to detect the position Ka (rotation angle) of the motor shaft SM.

[0035] In the 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 according to the various drive signals (Mt, etc.). Specifically, in the control of the solenoid valve, the drive signals Va, Vb are determined so that the first and second control valves VA, VB are supplied with power. 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 controller EA, according to the target pressure Pt and the drive signal Mt calculated from 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).

[0036] <Modulator device SB> A modulator device SB is provided between the brake control device SA and the wheel cylinder CW. The modulator device SB executes anti-lock brake control to suppress wheel lock, traction control to suppress wheel spin, and anti-skid control (so-called ESC) to suppress understeer and oversteer to improve the directional stability of the vehicle.

[0037] In the braking system for the front wheels WHf (i.e., the front wheel connecting passage HSf), the supply pressure Pm is supplied from the master cylinder CM to the modulator device SB. On the other hand, in the braking system for the rear wheels WHr (i.e., the rear wheel connecting passage HSr), the servo pressure Pc is directly supplied from the hydraulic pressure generating unit PS to the modulator device SB. In the modulator device 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) for the front and rear wheel cylinders CWf, CWr. The modulator device SB is composed of an actuator YB and a controller EB.

[0038] The actuator YB of the modulator device SB is disposed in the communication path HS between the actuator YA of the brake control device SA and the wheel cylinder CW. The actuator YB includes an electric motor, a fluid pump, a solenoid valve, and a supply pressure sensor. The supply pressure Pm is detected by the supply pressure sensor (not shown). The supply pressure Pm is input to the controller EB. The configuration of the actuator YB is well known, and therefore a description thereof will be omitted.

[0039] In the modulator device SB, the actuator YB is controlled by the controller EB. The controller EB is connected to a communication bus BS. Therefore, the controllers EA and EB can share signals via the communication bus BS. Various signals, such as the wheel speed Vw, the steering angle Sa, the yaw rate Yr, the longitudinal acceleration Gx, and the lateral acceleration Gy, are input to the controller EB. The vehicle speed Vx is calculated based on the wheel speed Vw in the controller EB. The controller EB performs anti-lock brake control, traction control, anti-skid control, etc. based on the various signals (Vw, Yr, etc.).

[0040] Normally, when the regenerative cooperative control is executed, the operation of the actuator YB is stopped. Therefore, the supply pressure Pm is outputted from the modulator device SB as the front wheel pressure Pwf, and the servo pressure Pc is outputted as the rear wheel pressure Pwr.

[0041] <Liquid pressure generating unit PS> An example of the configuration 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, 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 ultimately adjusted by the servo pressure Pc.

[0042] <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 will be 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 the axes Jm, Jk, Jn, and Jc (i.e., the parallel direction) 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." The rotation axis Jk of the rotating member BK is also the rotation axis of the bearing BC that supports the conversion mechanism GH (particularly, the rotating member BK).

[0043] In a member (NC, BD, etc.) that can move 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 moves in the forward direction Ha, the volume of the control chamber Rc decreases and its internal pressure Pc (servo pressure) increases. In contrast, when the control piston NC moves in the reverse direction Hb, the volume of the control chamber Rc increases and the servo pressure Pc decreases.

[0044] 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. Conversely, the rotational motion of the electric motor MT in the reverse direction Hg corresponds to the backward direction Hb of the linear member BD. Therefore, 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.

[0045] When a current Ims (also called "forward current") is supplied to rotate the electric motor MT in a forward direction Hs, the direction of rotation of the electric motor MT is determined by the magnitude relationship between the torque (also called "forward operating torque") output from the electric motor MT and the torque (also called "reverse operating torque") input to the electric motor MT by the servo pressure Pc. Specifically, when the forward operating torque is greater than the reverse operating torque, the electric motor MT rotates in the forward direction Hs, and the servo pressure Pc is increased. When the forward operating torque and the reverse operating torque are equal, the electric motor MT does not rotate, and the servo pressure Pc is maintained. When the reverse operating torque is greater than the forward operating torque, the electric motor MT rotates in the reverse direction Hg, and the servo pressure Pc is decreased. Note that when a current Img (called "reverse current" and a current in the opposite direction to the forward current Ims) is supplied to rotate the electric motor MT in the reverse direction Hg, the electric motor MT is driven to rotate in the reverse direction Hg.

[0046] <Configuration of the hydraulic pressure generating unit PS> The hydraulic pressure generating unit PS is composed of a sub-housing HGs, an electric motor MT, a rotation angle sensor KA, a speed reducer GS, a conversion mechanism GH, and a control piston NC, and is assembled to the main housing HGc.

[0047] The sub-housing HGs holds the components (MT, GS, GH, etc.) that make up the hydraulic pressure generating unit PS. The sub-housing HGs is divided into multiple parts to facilitate assembly of the components. For example, the sub-housing HGs is divided into a motor housing HGm and a gear housing HGg. In other words, the sub-housing HGs is a general term for the motor housing HGm and the gear housing HGg. In other words, the motor housing HGm and the gear housing HGg are parts of the sub-housing HGs.

[0048] An electric motor MT is attached to the motor housing HGm. The electric motor MT is a power source (pressurizing source) for generating a servo pressure Pc (hydraulic pressure in the control cylinder CC). Here, "power" refers to energy required to move movable members (BK, BD, etc.) in the hydraulic pressure generating unit PS. For example, power is defined as a physical quantity, energy per unit time (also called "power"). A rotational power Tm (also called "first rotational power") is output from the electric motor MT. 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).

[0049] A three-phase brushless motor is adopted for the electric motor MT. 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 within a 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 from a controller EA (particularly, a drive circuit DR) via the motor line Lm.

[0050] 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 bearings BB (e.g., bearings) 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."

[0051] 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 order to detect the rotation angle Ka for switching the three-phase currents, a rotation angle sensor KA is provided in the electric motor MT (brushless motor). The detected rotation angle Ka is transmitted to the controller EA via the sensor line Ls. In the controller EA, the switching element of the drive circuit DR is 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, a first rotational power Tm is output from the electric motor MT to the reducer GS.

[0052] A reducer GS is attached to the gear housing HGg. A planetary gear mechanism is used for the reducer GS. The reducer GS (planetary gear mechanism) reduces the speed of the first rotational power Tm output from the electric motor MT and outputs a second rotational power Tn. Specifically, the reducer GS reduces the speed input from the electric motor MT and increases the torque input from the electric motor MT. The second rotational power Tn is then output from the reducer GS to the conversion mechanism GH.

[0053] The reducer GS (planetary gear mechanism) is a gear mechanism in which multiple planetary gears Gp revolve around a sun gear Gt while rotating on their own axis. The reducer GS is composed of a sun gear Gt, an internal gear Gu, planetary gears Sp, and a planet carrier Ca. The sun gear Gt (also called "sun gear") is fixed to a motor shaft SM. Therefore, the sun gear Gt rotates integrally with the motor shaft SM. The internal gear Gu (also called "inner gear") is fixed to a gear housing HGg so as not to rotate around the rotation axis Jk. The planetary gear Gp is ​​supported by the planet carrier Ca and meshes with the sun gear Gt and the internal gear Gu.

[0054] The planetary carrier Ca is rotatably supported by the gear housing HGg via a bearing BC (e.g., a bearing). For example, the planetary carrier Ca is integrated with the bearing BC. In detail, a groove is formed on the outer periphery of the planetary carrier Ca to form the inner ring of the bearing BC. Then, the outer ring of the bearing BC is press-fitted and fixed into the gear housing HGg. The planetary carrier Ca is fixed to the rotating member BK of the conversion mechanism GH. In the reduction gear GS, a first rotational power Tm is input to the sun gear Gt from the electric motor MT (particularly, the motor shaft SM), and a second rotational power Tn is output from the planetary carrier Ca to the conversion mechanism GH (particularly, the rotating member BK).

[0055] A partition plate SU is fixed to the internal gear Gu. A lubricant (e.g., grease) is used in the reducer GS and the like. The partition plate SU is provided to prevent the lubricant from scattering and affecting the electric motor MT, the rotation angle sensor KA, and the like. The partition plate SU has a disk shape and has a through hole at the center so that the motor shaft SM can pass through. The partition plate SU may be fixed to the gear housing HGg or the motor housing HGm.

[0056] The conversion mechanism GH is held in a gear housing HGg. The conversion mechanism GH is composed of a rotating member BK that rotates and a linearly-moving member BD that moves linearly. In the conversion mechanism GH, the rotating member BK is fixed to the reducer GS (particularly, the planetary carrier Ca). The conversion mechanism GH is supported in a rotatable state by the gear housing HGg via a bearing BC (such as a bearing) that supports the planetary carrier Ca. Therefore, the rotation axis Jk of the rotating member BK is also the rotation axis Jk of the bearing BC.

[0057] Since the rotating member BK is connected to the planetary carrier Ca, the second rotational power Tn output from the planetary carrier Ca 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."

[0058] The conversion mechanism GH can convert both rotational motion to linear motion and linear motion to rotational motion. In the operation of the conversion mechanism GH, the former is called "normal operation" and the latter is called "reverse operation". That is, in normal operation, the rotational power of the rotating member BK is converted into the linear power of the linear motion member BD. That is, in normal operation, the power is transmitted from the rotating member BK to the linear motion member BD. In contrast, in reverse operation, the linear power of the linear motion member BD is converted into the rotational power of the rotating member BK. That is, in reverse operation, the power is transmitted from the linear motion member BD to the rotating member BK. Note that the efficiency in normal operation (the ratio of the linear power, which is the output, to the rotational power, which is the input) is called "normal efficiency", and the efficiency in reverse operation (the ratio of the rotational power, which is the output, to the linear power, which is the input) is called "reverse efficiency". The conversion mechanism GH, which can transmit power in both directions, has not only normal efficiency but also reverse efficiency.

[0059] 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 a planetary carrier Ca 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 an outer peripheral surface Mok of the rotating member BK. Similarly, a ball screw groove Mzd is also formed on an 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).

[0060] In a ball screw mechanism employed as the conversion mechanism GH, a ball screw shaft (an inner member, also referred to as a "shaft member") is the rotating member BK, and a ball screw nut (an outer member, also referred to as a "nut member") is the linear motion member BD. In this configuration, a screw groove Mzk is formed on an outer circumferential surface Mok of the rotating member BK (inner member), and a screw groove Mzd is formed on an inner circumferential surface Mid of the linear motion member BD (outer member). Then, the outer circumferential groove Mzk and the inner circumferential groove Mzd are engaged with each other via a ball BL. Conversely, in the ball screw mechanism, the nut member (outer member) may be the rotating member BK, and the shaft member (inner member) may be the linear motion member BD.

[0061] A control piston NC (corresponding to a "second piston") is fixed to the linear motion member BD. A control cylinder CC (a cylindrical hole, corresponding to a "second cylinder") is formed in the main housing HGc. The control piston NC is inserted into the control cylinder CC. More specifically, the control piston NC has a cylindrical shape with a bottom. The outer peripheral surface Mon of the control piston NC is inserted into the inner peripheral surface Mic of the control cylinder CC. More specifically, two seal members SL are fitted into a seal groove formed in the inner peripheral surface Mic of the control cylinder CC. The seal member SL seals the outer peripheral surface Mon of the control piston NC and the inner peripheral surface Mic of the control cylinder CC.

[0062] Inside the control cylinder CC, a control chamber Rc (hydraulic pressure chamber) is formed by the control piston NC. The control cylinder CC (particularly, the control chamber Rc) is provided with a discharge portion (not shown, a hole penetrating the main housing HGc). The discharge portion (through hole) is connected to the servo path HU and the rear wheel communication path HSr. That is, since the control chamber Rc is connected to the servo chamber Ru and the rear wheel cylinder CWr, the servo pressure Pc is supplied to the servo chamber Ru and the rear wheel cylinder CWr.

[0063] A rotation-preventing member MD is fixed to the main housing HGc. For example, a long, thin rod-shaped member (e.g., a pin member) is used for the rotation-preventing member MD. The rotation-preventing member MD prevents the rotation of the linear motion member BD (rotation around the rotation axis Jk). The linear motion member BD has a flange portion Fd, and a notch into which the rotation-preventing member MD can be fitted is formed. The rotation-preventing member MD engages with the notch, thereby restraining (limiting) the rotation of the linear motion member BD. Therefore, when the rotating member BK is rotationally driven, the linear motion member BD moves in the axial direction Hj (forward direction Ha or backward direction Hb).

[0064] The state in which the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC are assembled into the sub-housing HGs (a collective term for HGm and HGg) is referred to as the "sub-assembly SY." Specifically, the members (CL, SM, KA, etc.) that constitute the electric motor MT are assembled into the motor housing HGm. In addition, the speed reducer GS, the conversion mechanism GH, and the control piston NC are assembled into the gear housing HGg.

[0065] When the subassembly SY is viewed in the radial direction Hk, the bearing BC supporting the conversion mechanism GH is housed in the subhousing HGs (particularly, the gear housing HGg), but the control piston NC protrudes from the subhousing HGs. In detail, when projected parallel to the direction perpendicular to the rotation axis Jk of the bearing BC (i.e., in the radial direction Hk), the projection of the bearing BC overlaps with the projection of the gear housing HGg, but the projection of the control piston NC does not overlap with the projection of the gear housing HGg. Here, "projection" refers to the shadow of an object being projected onto a flat surface (projection surface), and refers to the projected image.

[0066] <Adjusting servo pressure Pc> In the brake control device SA, 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., axial torque) of the electric motor MT is converted by the conversion mechanism GH into a linear power Fn (i.e., thrust) of the linearly moving member BD (resulting in the control piston NC). As a result, the servo pressure Pc is generated and adjusted by the control piston NC moving in the axial direction Hj. Specifically, the servo pressure Pc is increased by the control piston NC moving in the forward direction Ha, and the servo pressure Pc is decreased by the control piston NC moving in the backward direction Hb. The adjustment (increase / decrease) of the servo pressure Pc will be explained below. Note that the hydraulic pressure generating unit PS is provided with a servo pressure sensor PC to detect the servo pressure Pc.

[0067] <Increase in servo pressure Pc> In FIG. 2, above the rotation axis Jk, a state in which the hydraulic pressure generating unit PS does not generate a servo pressure Pc is illustrated. In this state, the control chamber Rc is connected to the master reservoir RV via the supply line HH, and the servo pressure Pc is "0 (atmospheric pressure)." The position of the linear motion member BD in this state is referred to as the "initial position." Also, the rotation angle Ka of the electric motor MT corresponding to the initial position is referred to as the "initial angle." In other words, the initial position corresponds to the zero point related to the linear motion member BD, and the initial angle corresponds to the zero point related to the rotation angle Ka.

[0068] 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 electric motor MT is driven in the forward rotation direction Hs to generate rotational power Tm. The rotational power Tm is transmitted to the conversion mechanism GH via the reducer GS and output as linear power Fn of the linear moving member BD. Then, the linear moving member BD moves the control piston NC in the forward direction Ha (the direction in which the volume of the control chamber Rc decreases). After the communication between the control chamber Rc and the master reservoir RV is cut off, the servo pressure Pc (the internal pressure of the control chamber Rc) is increased from "0 (atmospheric pressure)". As a result, brake fluid BF pressurized to servo pressure Pc is output from the control chamber Rc of the control cylinder CC to the servo chamber Ru via the servo path HU, and is also output to the rear wheel cylinder CWr via the rear wheel communication path HSR.

[0069] <Maintaining servo pressure Pc> When the braking demand value becomes constant, the target pressure Pt is maintained and the servo pressure Pc is made constant. For example, the linear motion member BD is maintained at a position displaced from the initial position (see the lower part of the rotation axis Jk in FIG. 2). At this time, the rotational force input to the electric motor MT by reverse operation due to the servo pressure Pc (i.e., reverse operation torque) and the rotational force output from the electric motor MT by forward operation (i.e., forward operation torque) are in balance.

[0070] <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 torque by the servo pressure Pc becomes greater than the forward torque by the electric motor MT, and the electric motor MT rotates in the reverse direction Hg. The linear motion member BD is moved in the backward direction Hb, and the volume of the control chamber Rc is increased. The brake fluid BF that was moved to the servo chamber Ru and the rear wheel cylinder CWr is returned toward the control chamber Rc, and the servo pressure Pc is reduced. Then, when the target pressure Pt is set to "0", the linear motion member BD is returned to the initial position, and the servo pressure Pc is set to "0". 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).

[0071] <Sub-assembly SY> In the subassembly SY, the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC are assembled to the subhousing HGs (a collective term for HGm and HGg). Here, the speed reducer GS, the conversion mechanism GH, and the control piston NC are also referred to as "power transmission members" because they transmit the power of the electric motor MT to generate the servo pressure Pc. In other words, the power transmission members are assembled to the gear housing HGg. The motor housing HGm and the gear housing HGg are then combined to form the subassembly SY. Therefore, in the hydraulic pressure generating unit PS, the subassembly SY is both a power generation source and a power transmission member.

[0072] In the main housing HGc, multiple cylinders (CM, CC, etc.) are machined and multiple solenoid valves (VA, VB, etc.) are attached. The cylinders, solenoid valves, etc. are connected by fluid paths (HS, HU, etc.). The braking control device SA performs its functions when all of these components function (operate) normally.

[0073] The hydraulic pressure generating unit PS is the most important component of the brake control device SA. Furthermore, the hydraulic pressure generating unit PS is both complex and expensive. For this reason, in an integrated brake control device SA, the hydraulic pressure generating unit PS is inspected individually to ensure efficient inspection. Specifically, in the brake control device SA, only the subassembly SY is inspected. A suitability inspection of the subassembly itself is called a "single inspection." In contrast, a suitability inspection of the entire brake control device SA, including the subassembly SY, is called a "total inspection." When inspecting the brake control device SA, a single inspection is first performed prior to the total inspection.

[0074] When the individual inspection confirms that the sub-assembly SY is operating normally, the sub-housing HGs (i.e., the sub-assembly SY) is assembled to the main housing HGc. This completes the brake control device SA (particularly the actuator YA). After that, a final inspection (i.e., an overall inspection) of the brake control device SA is performed. In the overall inspection, the presence or absence of leakage, the operation of the brake control device SA as a whole, etc. are checked.

[0075] For example, assume that an inspection procedure is adopted in which the inspection at the subassembly SY stage (i.e., individual inspection) is omitted and inspection is carried out only after all the elements constituting the brake control device SA are assembled. In such an inspection procedure, even if an abnormality is detected in the brake control device SA, it is not possible to identify which part is abnormal. Therefore, even if the abnormality is minor, the entire brake control device SA will be discarded.

[0076] In contrast to this, in the braking control device SA, first, the subassembly SY is judged to be abnormal / normal (suitable or unsuitable) through individual inspection. Then, the subassembly SY that is confirmed to be operating normally is assembled into the main housing HGc. Therefore, if an abnormality is judged in the overall inspection, the abnormality occurs in a part other than the subassembly SY. The subassembly SY that is confirmed to be operating normally is removed from the main housing HGc where the abnormality occurs, and is reassembled into another main housing HGc. In this way, in the braking control device SA, the inspection procedure is made more efficient by inspection through individual inspection. As a result, waste associated with the disposal of parts is reduced.

[0077] In the subassembly SY, the bearing BC that supports the reducer GS and the conversion mechanism GH (particularly the rotating member BK) is housed in the subhousing HGs, but at least the control piston NC protrudes from the subhousing HGs. Specifically, when projected parallel to the radial direction Hk (direction perpendicular to the rotation axis Jk of the bearing BC), the projected image of the bearing BC and the projected image of the gear housing HGg overlap on the projection plane. In other words, the projections of the reducer GS and the conversion mechanism GH have portions that overlap with the projection of the gear housing HGg. In contrast, the projected image of the control piston NC and the projected image of the gear housing HGg do not overlap. By adopting this structure in the subassembly SY, individual inspection can be easily performed.

[0078] Furthermore, in the subassembly SY, the electric motor MT (particularly the electromechanical portion) is disposed further outward from the main housing HGc. This allows the electric motor MT to be appropriately disposed, and also allows the radial dimensions Hk of the components housed in the motor housing HGm to be enlarged. As a result, the degree of freedom in the mounting layout of the brake control device SA is improved.

[0079] <Assembly of sub-assembly SY> A method of assembling the subassembly SY to the main housing HGc will be described with reference to the schematic diagram of FIG. 3. The subassembly SY is assembled to the main housing HGc in a detachable state. For example, the gear housing HGg supporting the reducer GS and the conversion mechanism GH (particularly the rotating member BK) has a flange portion Fg extending in the radial direction Hk. The flange portion Fg of the gear housing HGg is provided with a through hole Ag (through hole) for the bolt BT. Similarly, the motor housing HGm supporting the electric motor MT also has a flange portion Fm extending in the radial direction Hk. The flange portion Fm of the motor housing HGm is also provided with a through hole Am (through hole) for the bolt BT.

[0080] The main housing HGc has a female-threaded screw hole (also called a "female-threaded hole"). The gear housing HGg and the motor housing HGm are fastened together to the main housing HGc via through holes Ag and Am. "Fastening together" means that two or more members are fastened together at the same time while being stacked. Specifically, the bolts BT are passed through the through holes Ag and Am (through holes in the flange portions Fg and Fm) and fastened into the female-threaded hole of the main housing HGc. In this way, the subassembly SY is fixed to the main housing HGc in a detachable state.

[0081] <Example of the first unit inspection of subassembly SY> A first example of the unit inspection of the subassembly SY will be described with reference to the schematic diagram of FIG. 4. In the unit inspection, the subassembly SY is inspected individually before it is assembled to the main housing HGc. Specifically, in the unit inspection, the operation of the members constituting the subassembly SY (i.e., the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC) is confirmed. If there is an abnormality in at least one of the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC, it is determined that there is an abnormality in the subassembly SY. On the other hand, if all of the electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC are normal, it is determined that the operation of the subassembly SY is normal.

[0082] In the unit inspection, the subassembly SY is attached to an inspection housing HGk, which is different from the main housing HGc. Then, the subassembly SY and the inspection housing HGk are combined to perform the unit inspection. An inspection cylinder CK is formed in the inspection housing HGk. Two seal members SL are fitted into seal grooves machined on the inner peripheral surface of the inspection cylinder CK. In addition, a rotation prevention member MD is assembled to the inspection cylinder CK. In the subassembly SY, a notch formed in a flange portion Fd of the linear motion member BD is fitted into the rotation prevention member MD. This prevents the linear motion member BD from rotating around the rotation axis Jk.

[0083] The subassembly SY (particularly, the control piston NC) is inserted into the inspection cylinder CK and sealed with a seal member SL. That is, an inspection chamber Rk (hydraulic pressure chamber) is formed in the inspection cylinder CK by the control piston NC. A mechanism in which elastic deformation occurs due to hydraulic pressure is connected to the inspection chamber Rk. This mechanism is also called a "load mechanism" and corresponds to the wheel cylinder CW for the brake control device SA. The inspection chamber Rk and the load mechanism are filled with brake fluid BF. When the control piston NC is moved in the forward direction Ha by the electric motor MT, the brake fluid BF discharged from the inspection chamber Rk is absorbed by the load mechanism. The elastic deformation generated at this time applies a load to the electric motor MT. An inspection pressure sensor PK is provided in the inspection chamber Rk or the load mechanism to detect the hydraulic pressure Pk (also called "inspection pressure") in the inspection cylinder CK.

[0084] The sub-assembly SY is detachably fixed to an attachment hole At machined in the inspection housing HGk. Specifically, the sub-assembly SY is fastened to the inspection housing HGk by a fastener (bolt, ring, etc.). For example, the sub-assembly SY is assembled to the inspection housing HGk in the same manner as the assembly method described with reference to FIG. 3. Specifically, the sub-housing HGs and the inspection housing HGk are fastened together by a bolt BT through through holes Ag and Am provided in the sub-housing HGs (the motor housing HGm and the gear housing HGg). Alternatively, a knock pin is fixed to the inspection housing HGk, and a positioning hole is provided in the sub-housing HGs. The position of the sub-assembly SY with respect to the inspection housing HGk may be determined by the knock pin and the positioning hole. In any case, the sub-assembly SY is fixed to the inspection housing HGk in a state in which it can be removed from the inspection housing HGk.

[0085] The motor wire Lm and the sensor wire Ls are drawn out from the sub-housing HGs. The motor wire Lm and the sensor wire Ls are connected to an inspection controller EK (also called an "inspection device"). The inspection controller EK includes a drive circuit for driving the electric motor MT and a microprocessor in which a test pattern PT is programmed.

[0086] Based on the test pattern PT, the test controller EK drives the electric motor MT. Specifically, a three-phase current Im is supplied to the electric motor MT via the motor line Lm to realize the test pattern PT. At this time, the three-phase current Im is switched based on the rotation angle Ka input via the sensor line Ls. The test controller EK judges whether the operation of the subassembly SY is normal or not. Specifically, the test pattern PT has a time series waveform set for increasing, maintaining, and decreasing the test pressure Pk. Based on the test pressure Pk generated in response to the test pattern PT, the suitability of the subassembly SY (whether the operation is normal or abnormal) is judged. In detail, when the difference between the target pressure Pt in the test pattern PT and the detection value Pk (test pressure) of the test pressure sensor PK is within a predetermined range, the normality of the subassembly SY is identified.

[0087] Alternatively, the suitability of the subassembly SY may be determined based on the relationship between the rotation angle Ka and the inspection pressure Pk. In the characteristics of the load mechanism, the relationship between the rotation angle Ka and the inspection pressure Pk is predetermined. Therefore, when the relationship between the rotation angle Ka and the inspection pressure Pk is within a predetermined range, the subassembly SY is determined to be normal. On the other hand, when the relationship is outside the predetermined range, the subassembly SY is determined to be abnormal. In either case, the suitability of the subassembly SY is determined based on the inspection pressure Pk.

[0088] When the subassembly SY operates normally, the electric motor MT, the reducer GS, the conversion mechanism GH, and the control piston NC all function normally. In contrast, when the difference between the target pressure Pt and the test pressure Pk exceeds a predetermined range, an abnormality in the subassembly SY is identified. In this case, an abnormality has occurred in at least one of the electric motor MT, the reducer GS, the conversion mechanism GH, and the control piston NC. For example, when an abnormality is found in the individual inspection, "poor output of the electric motor MT," "reduced efficiency in the reducer GS and the conversion mechanism GH," "fluid leakage in the control piston NC," etc. have occurred.

[0089] After the individual inspection is completed, the subassembly SY is removed from the inspection housing HGk. Then, if the operation of the subassembly SY is normal, the subassembly SY is assembled to the main housing HGc. The assembly of the subassembly SY to the main housing HGc is also fixed in a removable state by fasteners. The subassembly SY is assembled to the main housing HGc, and an overall inspection is performed. If an abnormality is determined in the overall inspection, the subassembly SY is removed from the main housing HGc and assembled to another main housing HGc. Then, the overall inspection is performed again. In this way, in the braking control device SA, the subassembly SY is inspected individually in advance, thereby reducing waste associated with disposal.

[0090] <Second unit inspection example of subassembly SY> A second unit inspection example of the subassembly SY will be described with reference to the schematic diagram of FIG. 5. In the first unit inspection example, the inspection cylinder CK (particularly, the inspection chamber Rk) formed in the inspection housing HGk was filled with the working fluid BF (braking fluid), and a load was applied to the electric motor MT, which is the power source of the hydraulic pressure generating unit PS, by a load member connected to the inspection chamber Rk. Instead, in the second inspection example, the load is applied by an elastic body DK (e.g., a compression spring) arranged in the inspection cylinder CK. Below, the differences will be mainly described.

[0091] As in the first unit inspection example, in the second unit inspection example, the subassembly SY is attached to an inspection housing HGk different from the main housing HGc. An inspection cylinder CK is formed in the inspection housing HGk. In the inspection housing HGk, an elastic body DK and a load sensor FK are provided between the bottom of the inspection cylinder CK and the bottom of the control piston NC. When the electric motor MT is driven and the control piston NC is moved in the forward direction Ha, the elastic body DK is compressed and deformed. The inspection cylinder CK is provided with a load sensor FK that detects an elastic force Fk (also called an "inspection load") of the elastic body DK against the control piston NC. In the second inspection example, the inspection cylinder CK is not filled with brake fluid BF.

[0092] The inspection load Fk in the second unit inspection example corresponds to the inspection pressure Pk in the first unit inspection example. The electric motor MT is driven by the inspection controller EK based on the inspection pattern PT. The inspection pattern PT has a time series waveform set for increasing, maintaining, and decreasing the inspection load Fk. The subassembly SY is judged for suitability (whether the operation is normal or abnormal) based on the inspection load Fk generated in response to the inspection pattern PT. For example, in the second inspection example, the subassembly SY is judged for suitability based on the relationship between the rotation angle Ka and the inspection load Fk. In the characteristics of the elastic body DK, the relationship between the rotation angle Ka and the inspection load Fk is predetermined. Therefore, when the relationship between the rotation angle Ka and the inspection load Fk is within a predetermined range, the subassembly SY is judged for suitability. On the other hand, when the relationship is out of the predetermined range, the subassembly SY is judged for abnormality. That is, the subassembly SY is judged for suitability (i.e., unit inspection) based on the inspection load Fk.

[0093] In the second unit inspection example, since the inspection chamber Rk is not filled with brake fluid BF, leakage from the control piston NC is determined by a leakage test using gas (air, etc.). For example, in a leakage test, gas is injected into the inspection chamber Rk, and the pressure (atmospheric pressure) in the inspection chamber Rk is increased. Then, the presence or absence of a leakage is determined based on the change in air pressure. That is, if there is a leakage, the air pressure will decrease, but if normal, the air pressure will be maintained. Therefore, in the second unit inspection example, a unit inspection of the subassembly SY is performed, and the same effect as in the first unit inspection example is achieved.

[0094] <Another embodiment of the brake control device SA> Other embodiments of the brake control device SA will be described below. In the other embodiments, the brake control device SA also provides the same effects as those described above (improved efficiency of unit inspection, elimination of waste due to disposal, etc.).

[0095] In the above embodiment of the brake control device SA, a single-type master cylinder CM is used. A tandem-type master cylinder CM may be used in the brake control device SA. In this configuration, two master chambers Rm are formed inside the master cylinder CM. Then, the hydraulic pressure generating unit PS supplies the servo pressure Pc to the servo chamber Ru, and the master chamber Rm supplies the wheel pressure Pw to the wheel cylinder CW. In this configuration, the brake control device SA may use 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 SA, 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.

[0096] Even in a configuration in which a tandem type master cylinder CM is employed, in the event of a power failure, the input chamber Rn is sealed, causing the master piston NM and the brake operating member BP to displace together. In this state (manual mode), the front and rear wheel pressures Pwf, Pwr are generated and adjusted by the supply pressure Pm from the driver's muscle force. On the other hand, when the power is normal, the master piston NM and the brake operating member BP can be displaced separately. In this state (by-wire mode), the front and rear wheel pressures Pwf, Pwr are generated and adjusted by the servo pressure Pc from the hydraulic pressure generating unit PS.

[0097] In the embodiment of the brake control device SA described above, 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 actuator YB. Then, either "connection between the hydraulic pressure generating unit PS and the actuator YB" or "connection between the apply unit AP and the 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 by 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 a 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 operating the brake operating member BP is output as the supply pressure Pm. At this time, the apply unit AP is separated from the simulator SS. In this configuration, the input cylinder CN, the input piston NN, and the first and second control valves VA and VB are omitted from the main housing HGc, and the above-mentioned switching valve is provided.

[0098] In a configuration in which the apply unit AP and the hydraulic pressure generating unit PS are arranged in parallel, the master piston NM always moves in conjunction with the brake operating member BP. In the event of a power failure, the connection between the apply unit AP and the actuator YB is selected, and the front and rear wheel pressures Pwf and Pwr are generated and adjusted by the supply pressure Pm due to the driver's muscle force. On the other hand, in the event of a normal power supply, the connection between the hydraulic pressure generating unit PS and the actuator YB is selected, and the front and rear wheel pressures Pwf and Pwr are generated and adjusted by the servo pressure Pc by the hydraulic pressure generating unit PS. Even in this configuration, in consideration of a fail-safe, the hydraulic pressure Pw of the wheel cylinder CW is generated by either the supply pressure Pm powered by the operating force of the brake operating member BP or the servo pressure Pc powered by the electric motor MT. Note that the brake fluid BF discharged from the master cylinder CM when the power supply is normal is absorbed by the stroke simulator SS.

[0099] The above-mentioned brake control device SA 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 brake control device SA may also be applied to a vehicle in which the regenerative device KG is omitted and in which regenerative cooperative control is not executed. In other words, the brake control device SA may be applied to various vehicles, regardless of whether or not regenerative cooperative control is executed.

[0100] In the configuration example of the hydraulic pressure generating unit PS described above, the conversion mechanism GH is fixed to the reducer GS, and the reducer GS is rotatably supported by the gear housing HGg via the bearing BC. That is, the conversion mechanism GH is supported by the bearing BC via the reducer GS. Alternatively, the conversion mechanism GH may be directly supported by the gear housing HGg. That is, a bearing supporting the conversion mechanism GH and a bearing supporting the reducer GS are provided separately. Even in this configuration, when the bearing supporting the conversion mechanism GH is projected parallel to the direction perpendicular to the rotation axis Jk (i.e., the radial direction Hk), the projection of the bearing overlaps with the projection of the gear housing HGg.

[0101] In the configuration example 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.

[0102] <Summary of the embodiment> An embodiment of the brake control device SA will be summarized. The brake control device SA adjusts the wheel pressure Pw of the wheel cylinder CW to control the braking force of the wheel WH. The brake control device SA is composed of a main housing HGc, a master piston NM (first piston), an electric motor MT, a reduction gear GS, a conversion mechanism GH, a control piston NC (second piston), and a sub-housing HGs. The main housing HGc is formed with a master cylinder CM (first cylinder) and a control cylinder CC (second cylinder).

[0103] The master piston NM is inserted into the master cylinder CM and moves in conjunction with the brake operating member BP to generate a supply pressure Pm in the master cylinder CM. In other words, if the power supply that supplies power to the brake control device SA fails, the supply pressure Pm is generated only by the operating force of the brake operating member BP. The wheel pressure Pw is then generated by the supply pressure Pm.

[0104] The electric motor MT generates a first rotational power Tm. The reducer GS reduces the speed of the first rotational power Tm and outputs a second rotational power Tn. The conversion mechanism GH converts the second rotational power Tn into a linear power Fn. The control piston NC is inserted into the control cylinder CC and is moved by the linear power Fn from the conversion mechanism GH to generate a servo pressure Pc in the control cylinder CC. That is, when the power supply is normal, the wheel pressure Pw is generated by the servo pressure Pc.

[0105] The electric motor MT, the speed reducer GS, the conversion mechanism GH, and the control piston NC are supported (held) by a sub-housing HGs, which is assembled to the main housing HGc.

[0106] The subassembly SY is formed by assembling the electric motor MT, the reducer GS, the conversion mechanism GH, and the control piston NC into the subhousing HGs. The subassembly SY is the most important element in the brake control device SA (i.e., the power generation source for the hydraulic pressure generating unit PS and the power transmission member). In the brake control device SA, a unit inspection is performed before an overall inspection so that the suitability of at least the subassembly SY can be confirmed. Specifically, the subassembly SY is attached to an inspection housing HGk that is different from the main housing HGc. Then, the operation of the subassembly SY is confirmed by combining the inspection housing HGk with the subassembly SY.

[0107] In the brake control device SA, the electric motor MT, the reducer GS, the conversion mechanism GH, and the control piston NC are held by a sub-housing HGs so that the sub-assembly SY can be easily inspected as a single unit. The sub-housing HGs includes a gear housing HGg to which a bearing BC supporting the conversion mechanism GH is fixed. When the sub-assembly SY is projected parallel to a direction perpendicular to the rotation axis Jk of the bearing BC (i.e., the radial direction Hk), the projection of the bearing BC overlaps with the projection of the gear housing HGg, but the projection of the control piston NC does not overlap with the projection of the gear housing HGg. In other words, the bearing BC supporting the conversion mechanism GH is accommodated in the gear housing HGg, but a structure is adopted in which the control piston NC protrudes from the sub-housing HGs. With this structure, the sub-assembly SY can be easily assembled to both the inspection housing HGk and the main housing HGc. This facilitates the inspection of the sub-assembly in the brake control device SA. That is, the inspection efficiency is improved and waste due to disposal can be reduced.

[0108] The subassembly SY is assembled to both the inspection housing HGk and the main housing HGc in such a manner that it can be easily removed. For example, the motor housing HGm and the gear housing HGg have through holes Ag and Am. The motor housing HGm and the gear housing HGg are fastened together to the main housing HGc by bolts BT via the through holes Ag and Am. Similarly, the motor housing HGm and the gear housing HGg are fastened together to the inspection housing HGk by bolts BT via the through holes Ag and Am. In this way, the subassembly SY is fixed to the main housing HGc and the inspection housing HGk in such a manner that it can be easily removed. [Explanation of symbols]

[0109] SA...Brake control device, SB...Modulator device, SX...Brake device, BP...Brake operation member (brake pedal), BF...Braking fluid (hydraulic fluid), YA...Actuator, EA...Controller, BS...Communication bus, CM...Master cylinder (first cylinder), NM...Master piston (first piston), Pm...Supply pressure (internal pressure of Rm), CW...Wheel cylinder, AP...Apply unit, NR...Input unit, PS...Hydraulic pressure generating unit, MT...Electric motor (brushless motor), VA, VB...First and second control valves, SP...Operation displacement sensor, Sp...Operation displacement (detected value of SP), PC...Servo pressure sensor, Pc...Servo pressure (internal pressure of Rc, detected value of PC), KA...Rotation angle sensor, Ka...Rotation angle (rotation position of SM), Pwf, Pwr...Front and rear wheel pressure, HGc...Main housing, HGs...Sub-housing (total of HGm, HGg) nominal value), HGm...motor housing (part of HGs), HGg...gear housing (part of HGs), KA...rotation angle sensor, GS...reduction gear (planetary gear mechanism), GH...conversion mechanism (rotation-linear conversion mechanism), BK...rotating member, BD...linear member, CC...control cylinder (second cylinder), NC...control piston (second piston), MD...rotation stop member, BC...bearing (support member of GH for HGg), Rc...control chamber (hydraulic chamber of CC), Tm...first rotational power (output of MT), Tn...second rotational power (output of GS), Fn...linear power (output of BD), SY...subassembly, HGk...inspection housing, CK...inspection cylinder, Rk...inspection chamber, Pk...inspection pressure, PK...inspection pressure sensor, Fk...inspection load, FK...load sensor, At...inspection hole, EK...inspection device (inspection controller), PT...inspection pattern, Jk...rotation axis of BC (rotation axis of BK).

Claims

1. a main housing in which first and second cylinders are formed; a first piston that is inserted into the first cylinder and moves in conjunction with a brake operating member to generate a supply pressure in the first cylinder; an electric motor that generates a first rotational power; a reducer that reduces the speed of the first rotational power and outputs a second rotational power; a conversion mechanism for converting the second rotational power into linear power; a second piston that is inserted into the second cylinder and moves by the linear power to generate a servo pressure in the second cylinder; a sub-housing that supports the electric motor, the reduction gear, the conversion mechanism, and the second piston and is assembled to the main housing; A vehicle braking control device comprising:

2. 2. The vehicle brake control device according to claim 1, the sub-housing includes a gear housing that fixes a bearing that supports the conversion mechanism, A vehicle braking control device, wherein when projected parallel in a direction perpendicular to the rotation axis of the bearing, the projection of the bearing overlaps with the projection of the gear housing, but the projection of the second piston does not overlap with the projection of the gear housing.

3. 3. The vehicle brake control device according to claim 2, the sub-housing includes a motor housing supporting the electric motor; A vehicle braking control device, wherein the motor housing and the gear housing are fastened together to the main housing.

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