Hydraulic pressure generating device

Abstract

A hydraulic pressure generating device is provided with: an electric motor that outputs rotational power; a conversion mechanism that outputs the rotational power input to the rotating member as the linear power of the linear motion member; a piston inserted into the cylinder and moving by linear power to increase the hydraulic pressure of the cylinder; and an intermediate member disposed between the linear motion member and the piston and capable of sliding with respect to the linear motion member and the piston. The piston has a first bottom portion and a first cylindrical portion, and the intermediate member has a second cylindrical portion and is inserted into the first cylindrical portion. Among the slits between the inner peripheral surface of the first cylindrical portion and the outer peripheral surface of the second cylindrical portion, a slit (Ska) at a position closer to the first bottom portion is narrower than a slit (Skb) at a position farther from the first bottom portion.

Description

Technical Field

[0001] This disclosure relates to hydraulic generating devices. Background Technology

[0002] As described in Patent Document 1, the applicant has developed a device in an electric cylinder device (also known as a "hydraulic generating device") to suppress the separation of the piston and the linear actuator, comprising: a housing having a cylinder; a piston disposed inside the cylinder; a rotating member rotating about a rotation axis; a linear actuator mounted on the rotating member such that it moves along a first direction along the rotation axis or a second direction opposite to the first direction, depending on the rotation of the rotating member, and presses the piston by moving in the first direction to reduce the volume of the liquid chamber of the cylinder; a first engaging portion disposed on the piston; and a second engaging portion disposed on the linear actuator, which restricts the separation of the linear actuator from the piston in the second direction by abutting against the first engaging portion.

[0003] In this device, a spacer 46 (also called an "intermediate component") is sandwiched between the end face 45a of the nut component 45 and the inner surface 71a of the piston 22. The nut component 45 presses the piston 22 forward in a forward direction Df via the spacer 46. The diameter of the outer peripheral surface 92b of the spacer 46 is smaller than the diameter of the inner peripheral surface 72a of the piston 22, and a gap is provided between the outer peripheral surface 92b and the inner peripheral surface 72a. Therefore, the piston 22 and the spacer 46 can move relative to each other in the radial direction. Here, the spacer (intermediate component) also functions as a mechanism to compensate for the effects of axial misalignment (also called an "axial misalignment compensation mechanism"). In addition, in the axial misalignment compensation mechanism, the larger the gap, the greater its effect. However, if the gap is increased, there are still issues with the positioning accuracy of the intermediate component under small loads (including no load).

[0004] Patent Document 1: Japanese Patent Application No. 2023-054971. Summary of the Invention

[0005] In view of the above-mentioned problems, the object of the present invention is to provide a technique for improving the positioning accuracy of intermediate components in a hydraulic generating device equipped with a shaft offset compensation mechanism.

[0006] The hydraulic generating device (PS) of the present invention includes: an electric motor (MT) that outputs rotational power (Tm); a conversion mechanism (GH) that outputs the rotational power (Tm) input to a rotating member (BK) as linear power (Fn) for a direct-acting member (BD); a piston (NC) inserted into a cylinder (CC) that moves by the linear power (Fn) to increase the hydraulic pressure (Pc) of the cylinder (CC); and an intermediate member (BE) disposed between the direct-acting member (BD) and the piston (NC) and capable of sliding relative to the direct-acting member (BD) and the piston (NC).

[0007] In the hydraulic generating device (PS) of the present invention, the piston (NC) has a first bottom (Btn) and a first cylindrical portion (Enn). Furthermore, the intermediate component (BE) has a second cylindrical portion (Ene) and is inserted into the first cylindrical portion (Enn). Moreover, in the gap between the inner circumferential surface (Min) of the first cylindrical portion (Enn) and the outer circumferential surface (Moe) of the second cylindrical portion (Ene), the gap (Ska) near the first bottom (Btn) is narrower than the gap (Skb) further away from the first bottom (Btn).

[0008] For example, at least one of the end faces (Mpe) of the intermediate component (BE) that contacts the first bottom (Btn) and the end face (Mqe) of the intermediate component (BE) that contacts the direct-moving component (BD) is a convex surface. According to this configuration, the positioning accuracy of the intermediate component BE can be improved. Furthermore, axial offset compensation can be appropriately performed.

[0009] In the hydraulic generating device (PS) of the present invention, the aforementioned rotating member (BK) can enter the aforementioned second cylindrical section (Ene). This shortens the axial length of the device. Furthermore, the aforementioned second cylindrical section (Ene) has a vent (Ae). This suppresses air pressure fluctuations within the intermediate member BE. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating the overall structure of the braking control device SC.

[0011] Figure 2 This is a partial cross-sectional view used to illustrate an embodiment of the hydraulic generating unit PS.

[0012] Figure 3 This is a partial sectional view of a first configuration example used to illustrate the positioning of the intermediate component BE.

[0013] Figure 4 This is a partial sectional view of a second configuration example used to illustrate the positioning of the intermediate component BE. Detailed Implementation

[0014] <Symbols of constituent parts, etc., and suffixes at the end of the symbols>

[0015] In the following explanation, components, processing units, signals, characteristics, and values ​​that share the same symbol, such as "CW," have the same function. The suffixes "f" and "r" appended to the symbols of each wheel are general symbols indicating which system they relate to on the front or rear wheels. For example, in the wheel cylinder CW provided on each wheel, it is expressed as "front wheel cylinder CWf, rear wheel cylinder CWr." Furthermore, the suffixes "f" and "r" can be omitted. When the suffixes "f" and "r" are omitted, each symbol represents its general term. For example, "CW" is the general term for the wheel cylinders provided on the front and rear wheels of a vehicle. Additionally, "CW" as a general term is also expressed as "CW (=CWf, CWr)."

[0016] 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 via a fluid path (connection path HS). Furthermore, various components (PS, etc.) within the first and second actuators YA and YB are connected via fluid paths. Here, a "fluid path" is the path used to move the brake fluid BF (working fluid), equivalent to piping, flow paths within the actuator, hoses, etc. In the following description, the connection path HS, reservoir path HR, input path HN, servo path HU, and replenishment path HH are all considered fluid paths.

[0017] <Vehicle Braking Control Device SC>

[0018] Reference Figure 1 The diagram illustrates the overall configuration of the brake control device SC, which includes a hydraulic generation unit PS. For example, the brake control device SC is used in hybrid vehicles or electric vehicles equipped with an electric motor for driving.

[0019] The vehicle is equipped with a regenerative braking device KG. The regenerative braking device KG consists of a generator GN ("electric motor / generator," or, also called a "regenerative generator") for energy regeneration, a control unit EG (also called a "regenerative controller") for the regenerative braking device KG, and a regenerative battery (not shown). The regenerative generator GN also serves as the electric motor for driving. During regenerative braking, the electric motor / generator GN operates as a generator, and the generated electricity is stored in the regenerative battery via the regenerative controller EG. At this time, a regenerative braking force Fg is applied to the wheels. For example, if the regenerative braking device KG is installed at the front wheel WHf, a regenerative braking force Fg is generated at the front wheel WHf.

[0020] The front and rear wheels WHf and WHr of the vehicle are equipped with braking devices SX (=SXf, SXr). The braking device SX consists of a brake caliper, friction components (e.g., brake pads), and a rotating component KT (e.g., a brake disc). Wheel cylinders CW (=CWf, CWr) are provided in the brake calipers (not shown). Hydraulic pressure Pw (referred to as "wheel pressure") within the wheel cylinders CW presses the friction components (not shown) against the rotating component KT (=KTf, KTr) fixed to each wheel WH. This provides a braking torque Tb to the wheel WH. As a result, a hydraulic braking force Fp is generated at the wheel WH.

[0021] The vehicle is equipped with a braking control component BP and various sensors (SP, etc.). The braking control component BP (e.g., the brake pedal) is an operating component used by the driver to decelerate the vehicle. The vehicle is equipped with a control displacement sensor SP that detects the operating displacement Sp of the braking control component BP. The operating displacement Sp is one of the state quantities (state variables) that display the amount of braking operation of the braking control component BP. In addition to the operating displacement sensor SP, hydraulic pressure Pn (referred to as "input pressure") in the input chamber Rn (described later) is used as another state quantity to represent the amount of braking operation. The input pressure Pn is detected by the input pressure sensor PN. The operating displacement Sp, input pressure Pn, etc., are collectively referred to as "braking operation quantity Ba". In addition, the sensors such as the operating displacement sensor SP and the input pressure sensor PN that detect the braking operation quantity Ba are called "braking operation quantity sensors BA".

[0022] The vehicle is equipped with a brake control unit SC. The brake control unit SC employs a so-called front-rear type (also known as "Type II") system, serving as a dual-system braking system. The brake control unit SC adjusts the actual wheel pressure Pw of each wheel cylinder CW. The brake control unit SC consists of two brake units SA and SB.

[0023] <First Braking Unit SA>

[0024] The first braking unit SA adjusts the hydraulic pressures Pwf and Pwr (front and rear wheel pressures) of the front and rear wheel cylinders CWf and CWr according to the operation of the braking operation component BP (brake pedal). The first braking unit SA consists of a first actuator YA and a first controller EA.

[0025] ≪First Actuator YA≫

[0026] The first actuator YA consists of an application unit AP, a hydraulic generation unit PS, and an input unit NR.

[0027] [Application Unit AP]

[0028] Based on the operation of the braking control component BP, the application unit AP outputs supply pressure Pm. The application unit AP consists of a single-cylinder master cylinder CM and a master piston NM.

[0029] A master piston NM is inserted into a single-cylinder 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 main 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 the flange Tu of the master piston NM. Here, the pressure-bearing area rm of the main chamber Rm is set to be equal to the pressure-bearing area ru of the servo chamber Ru.

[0030] When not braking, the master piston NM is in its final retracted position (i.e., the position where the volume of the master chamber Rm is at its 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 known as the "atmospheric reservoir"). If the brake operating component BP is operated, the master piston NM moves in the forward direction Ma (the direction in which the volume of the master chamber Rm decreases). This movement disconnects the connection between the master chamber Rm and the master reservoir RV. Furthermore, if the master piston NM moves further in the forward direction Ma, the supply pressure Pm (the internal pressure of the master chamber Rm, also known as the "master pressure") increases from "0 (atmospheric pressure)". As a result, brake fluid BF pressurized to the supply pressure Pm is output (pressurized) from the master cylinder CM (especially the master chamber Rm).

[0031] [Hydraulic generation unit PS]

[0032] The hydraulic generating unit PS (also known as the "hydraulic generating device") uses the electric motor MT as a power source to generate the front and rear wheel pressures Pwf and Pwr. The front and rear wheel pressures Pwf and Pwr are adjusted by the servo pressure Pc generated by the electric motor MT. Specifically, the hydraulic generating unit PS is connected to the servo chamber Ru via the servo path HU (fluid path). Additionally, the hydraulic generating unit PS is connected to the rear wheel cylinder CWr via the rear wheel connection path HSr (fluid path). Furthermore, to replenish the brake fluid BF in the hydraulic generating unit PS when it is insufficient, the hydraulic generating unit PS is connected to the main reservoir RV via the replenishment path HH (fluid path).

[0033] When the hydraulic generating unit PS is operating (i.e., during braking), the supply line HH is cut off. This disconnects the hydraulic generating unit PS from the main reservoir RV. In the front wheel braking system, a supply pressure Pm (main pressure) is generated by supplying servo pressure Pc to the servo chamber Ru. Furthermore, the hydraulic pressure Pwf (front wheel pressure) of the front wheel cylinder CWf is generated by the supply pressure Pm. Conversely, in the rear wheel braking system, the hydraulic pressure Pwr (rear wheel pressure) of the rear wheel cylinder CWr is generated by directly supplying servo pressure Pc to the rear wheel cylinder CWr. A servo pressure sensor PC is installed in the hydraulic generating unit PS to detect the servo pressure Pc. Details of the hydraulic generating unit PS will be described later.

[0034] [Input Unit NR]

[0035] Regenerative coordinated control is achieved through the input unit NR. During braking, "regenerative coordinated control" coordinates the hydraulic braking force Fp (braking force based on wheel pressure Pw) and the regenerative braking force Fg (braking force based on the regenerative generator GN) to efficiently recover the vehicle's kinetic energy into electrical energy. In regenerative coordinated control, a state is achieved where the braking actuation component BP is operated, but wheel pressure Pw is not generated. The input unit NR consists of the input cylinder CN, the input piston NN, the first control valve VA, the second control valve VB, the stroke simulator SS, and the input pressure sensor PN.

[0036] 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 the brake operating component BP, so as to be linked with the action of the brake operating component BP (brake pedal). There is a gap Ks (also called "separation distance") between the end face of the input piston NN and the end face of the master piston NM. Regenerative coordinated control is achieved by adjusting the separation distance Ks according to the servo pressure Pc.

[0037] The input chamber Rn of the input unit NR is connected to the reaction chamber Rs of the application unit AP via the input path HN (fluid path). A normally closed first control valve VA is installed in the input path HN. The input path HN is connected to the main reservoir RV via the reservoir path HR (fluid path) between the first control valve VA and the reaction chamber Rs. A normally open second control valve VB is installed in the reservoir path HR. The first and second control valves VA and VB are on / off type solenoid valves. A stroke simulator SS is connected to the input path HN between the first control valve VA and the reaction chamber Rs.

[0038] Without power supply to the first and second control valves VA and VB, the first control valve VA is closed, and the second control valve VB is open. With the first control valve VA closed, the input chamber Rn is sealed, achieving fluid lock. This causes the main piston NM to move integrally with the braking operating component BP. Furthermore, with the second control valve VB open, the stroke simulator SS and the reaction chamber Rs are connected to the main reservoir RV.

[0039] When the first and second control valves VA and VB are powered, the first control valve VA opens and the second control valve VB closes. This allows the main piston NM to move independently of the braking actuation component BP. At this time, the input chamber Rn is connected to the stroke simulator SS, so the operating force of the braking actuation component BP is generated through the stroke simulator SS. An input pressure sensor PN is installed on the input path HN between the input chamber Rn and the first control valve VA to detect the input pressure Pn. Furthermore, the input pressure Pn is also the hydraulic pressure within the stroke simulator SS.

[0040] ≪First Controller EA≫

[0041] The first actuator YA is controlled by the first controller EA. The first controller EA consists of a microprocessor MP and a drive circuit DR. The first controller EA is connected to the communication bus BS so that it can share signals (detected values, calculated values, control flags, etc.) with other controllers (EB, EG, etc.).

[0042] The first controller EA directly inputs various signals, including the operating displacement Sp (detected by the operating displacement sensor SP), input pressure Pn (detected by the input pressure sensor PN), servo pressure Pc (detected by the servo pressure sensor PC), and motor rotation angle Ka (detected by the rotation angle sensor KA). Furthermore, it inputs various signals, such as the supply pressure Pm and the ultimate regenerative braking force Fx, from the communication bus BS to the first controller EA. Additionally, the first controller EA outputs the target regenerative braking force Fh (the target value of the regenerative braking force Fg) from the communication bus BS. Moreover, in the regenerative controller EG, based on the target regenerative braking force Fh (target value) obtained from the communication bus BS, it controls the actual regenerative braking force Fg.

[0043] In the first controller EA (specifically, the microprocessor MP), a voltage regulation control algorithm is programmed. This "voltage regulation control" is used to regulate the wheel pressure Pw (=Pwf, Pwr), and includes regenerative coordination control. Voltage regulation control is performed based on the various signals (Sp, Pc, etc.) mentioned above. Based on the voltage regulation control algorithm, the electric motor MT and various solenoid valves (VA, etc.) are driven via the drive circuit DR. In the drive circuit DR, an H-bridge circuit (also called an "inverter circuit") is formed by switching elements (e.g., MOS-FETs) to drive the electric motor MT. Additionally, the drive circuit DR includes switching elements to drive various solenoid valves. Furthermore, the drive circuit DR includes a motor current sensor (not shown) that detects the supply current Im (also called "motor current") to the electric motor MT. A rotation angle sensor KA is provided on the electric motor MT to detect the position Ka (rotation angle) of the motor shaft SM.

[0044] In the first controller EA, the drive signals Va and Vb of the first and second control valves VA and VB, and the drive signal Mt of the electric motor MT are calculated. Furthermore, the aforementioned switching elements are driven according to various drive signals (Mt, etc.). Specifically, in the control of the solenoid valves, power is supplied to the first and second control valves VA and VB based on the drive signals Va and Vb. This opens the first control valve VA and closes the second control valve VB. In the control of the electric motor MT, a target pressure Pt is calculated based on the operating displacement Sp, etc. The "target pressure Pt" is a target value corresponding to the servo pressure Pc (actual value). Furthermore, in the first controller EA, based on the drive signal Mt calculated based on the target pressure Pt and the servo pressure Pc, the electric motor MT is controlled to make the servo pressure Pc (actual value) approach and match the target pressure Pt (target value).

[0045] <Second Braking Unit SB>

[0046] A second braking unit SB is installed between the first braking unit SA and the wheel cylinder CW. Anti-lock braking control, traction control, and anti-skid control are performed via the second braking unit SB. In the braking system of the front wheel WHf (i.e., the front wheel connection path HSf), the supply pressure Pm is supplied from the master cylinder CM to the second braking unit SB. On the other hand, in the braking system of the rear wheel WHr (i.e., the rear wheel connection path HSr), the servo pressure Pc is directly supplied from the hydraulic generation unit PS to the second braking unit SB. The second braking unit SB adjusts (increases or decreases) the supply pressure Pm and the servo pressure Pc, and outputs the hydraulic pressures Pwf and Pwr (front and rear wheel pressures) for the front and rear wheel cylinders CWf and CWr, respectively. The configuration of the second braking unit SB is well-known, so its description is omitted.

[0047] Normally, when regenerative coordination 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 output from the second braking unit SB as the front wheel pressure Pwf, and the servo pressure Pc is output as the rear wheel pressure Pwr.

[0048] <Implementation of the Hydraulic Generating Unit PS>

[0049] Reference Figure 2 A partial cross-sectional view is provided to illustrate the implementation of the hydraulic generation unit PS. In the hydraulic generation unit PS (hydraulic generation device), an electric motor MT is used as a pressure source (also called a "power source") to generate servo pressure Pc. Furthermore, the wheel pressure Pw (=Pwf, Pwr) is adjusted by the servo pressure Pc.

[0050] ≪The shape of the constituent parts and the direction of their movement≫

[0051] First, the directions related to shape and movement of the elements constituting the hydraulic generating unit PS are defined. In the hydraulic generating unit PS, in the state where no axial offset occurs, the rotation axis Jm of the electric motor MT (especially the motor shaft SM), the rotation axis Jk of the rotating component BK, the central axis Jn of the control piston NC, the central axis Jc of the control cylinder CC, and the central axis Je of the intermediate component BE are aligned in a straight line. The direction along the axes Jm, Jk, Jn, Jc, Je (i.e., the direction parallel to them) is called the "axial direction Hj". In contrast, the direction perpendicular to the axes Jm, Jk, Jn, Jc, Je is called the "radial direction Hk". Therefore, the radial direction Hk is perpendicular to the axial direction Hj.

[0052] In components capable of moving along the axial direction Hj (NC, BE, BD, etc.), the direction approaching the bottom surface Mbc of the control cylinder CC is called the "forward direction Ha". Conversely, the direction away from the bottom surface Mbc of the control cylinder CC is called the "reverse direction Hb". Therefore, if the control piston NC moves in the forward direction Ha, the volume of the control chamber Rc decreases, while its internal pressure Pc (servo pressure) increases. Conversely, if the control piston NC moves in the reverse direction Hb, the volume of the control chamber Rc increases, while the servo pressure Pc decreases.

[0053] In the relationship between the rotational motion of the electric motor MT and the linear motion of the direct-acting component BD (resulting in the control piston NC), the forward rotation direction Hs of the electric motor MT corresponds to the forward movement direction Ha of the direct-acting component BD. Conversely, the reverse rotational motion Hg of the electric motor MT corresponds to the backward movement direction Hb of the direct-acting component BD. Therefore, if the electric motor MT rotates in the forward direction Hs, the direct-acting component BD moves in the forward direction Ha. As a result, the volume of the control chamber Rc decreases, while the servo pressure Pc increases. Conversely, if the electric motor MT rotates in the reverse direction Hg, the direct-acting component BD moves in the backward movement direction Hb. As a result, the volume of the control chamber Rc increases, while the servo pressure Pc decreases.

[0054] Composition of the Hydraulic Generating Unit PS

[0055] The hydraulic generating unit PS consists of a housing HG, an electric motor MT, a rotation angle sensor KA, a reducer GS, a conversion mechanism GH, an anti-rotation component MD, a control piston NC, and an intermediate component BE.

[0056] The housing HG holds the various components (MT, GS, etc.) that make up the hydraulic generating unit PS. The housing HG is divided into multiple parts to assemble the components. For example, the housing HG is divided into a cylinder housing HGc and a motor housing HGm. The motor housing HGm is assembled with the cylinder housing HGc, ultimately forming a single integrated housing HG. In other words, the housing HG is the collective term for the cylinder housing HGc and the motor housing HGm.

[0057] Furthermore, the housing HG can also be integrated with the first controller EA. Specifically, the first controller EA consists of a control board that mounts the microprocessor MP and the drive circuit DR, and a controller housing (not shown) that houses the control board. Moreover, the controller housing is assembled and integrated with the housing HG. The reducer GS and the conversion mechanism GH are held by the housing HG (especially the cylinder housing HGc). In addition, the electric motor MT is held by the housing HG (especially the motor housing HGm).

[0058] A control cylinder CC (equivalent to a "cylinder") is formed in the housing HG (especially the cylinder housing HGc). A control piston NC (equivalent to a "piston") is inserted into the control cylinder CC. Furthermore, a control chamber Rc (hydraulic chamber) is formed by the control cylinder CC and the control piston NC. A discharge section Au is provided in the control cylinder CC (especially the control chamber Rc). A servo circuit HU and a rear wheel connection circuit HSr are connected to the discharge section Au. That is, the control chamber Rc is connected to the servo chamber Ru and the rear wheel cylinder CWr. Thus, servo pressure Pc is supplied (output) to the servo chamber Ru and the rear wheel cylinder CWr.

[0059] The electric motor MT is the power source (pressurization source) used to generate servo pressure Pc (hydraulic pressure within the control cylinder CC). Here, "power" refers to the energy required to move the movable parts (NC, BK, BD, etc.) in the hydraulic generation unit PS. For example, power, as a physical quantity, is defined as the energy per unit time (also called "power"). The electric motor MT outputs rotational power Tm (also called "first rotational power"). The rotational power Tm of the electric motor MT is the power obtained by multiplying the shaft torque of the electric motor MT by the rotational speed of the electric motor MT (specifically, the motor shaft SM). Furthermore, the linear power Fn of the direct-acting part BD (described later) is the power obtained by multiplying the thrust of the direct-acting part BD (the force acting on the axial direction Hj) by the linear velocity of the direct-acting part BD (the velocity of the axial direction Hj).

[0060] The electric motor MT is a three-phase brushless motor. The electric motor MT is mounted within 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 the "coil (winding)") is fixed within the motor housing HGm. The motor coil CL is also called the "stator." Motor wires Lm are connected to the motor coil CL. Power is supplied to the motor coil CL via the motor wires Lm from the first controller EA (specifically, the drive circuit DR).

[0061] The motor shaft SM (also simply referred to as the "shaft") is rotatably supported on the motor housing HGm (which is also the motor coil CL) via a bearing BB fixed inside the motor housing HGm. A motor magnet Mm (a permanent magnet) is fixed to the outer periphery of the shaft SM of the electric motor MT. For example, the motor magnet Mm is attached to the motor shaft SM by adhesive or similar means. The motor shaft SM is also called the "rotor".

[0062] In a 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 the collective term for the current flowing through the U-phase, V-phase, and W-phase. The motor current Im of the three phases involved in 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, rotating the electric motor MT. Moreover, the first rotational power Tm is output from the electric motor MT to the reducer GS.

[0063] A rotation angle sensor KA is installed in the electric motor MT (brushless motor) to detect the motor's rotation angle Ka. The rotation angle sensor KA consists of a sensor disk Ds, a sensor magnet Ms, a sensor substrate Kb, and sensor wires Ls. The sensor disk Ds is fixed to the motor shaft SM so that it rotates integrally with the motor shaft SM. The sensor magnet Ms is installed on the sensor disk Ds. The sensor substrate Kb is fixed to the motor housing HGm. A hole is formed in the sensor substrate Kb to allow the motor shaft SM to pass through. A detection section using a magnetic field detection element is provided around the hole to detect changes in the magnetic field generated when the motor shaft SM (i.e., the sensor magnet Ms) rotates. The signal detected by the magnetic field detection element is transmitted to the first controller EA (specifically, the microprocessor MP) via the sensor wires Ls.

[0064] The speed reducer GS reduces the first rotational power Tm output from the electric motor MT, outputting a second rotational power Tn. Specifically, the input shaft of the speed reducer GS is fixed to the motor shaft SM. Furthermore, the output shaft of the speed reducer GS is fixed to the rotating component BK of the conversion mechanism GH. The speed reducer GS reduces the speed input from the electric motor MT and increases the torque input from the electric motor MT. Moreover, the second rotational power Tn is output from the speed reducer GS to the conversion mechanism GH.

[0065] For example, a planetary gear mechanism is used as the reducer GS. In a planetary gear mechanism, multiple planetary gears rotate on their own axes while revolving around a sun gear. The reducer GS consists of a sun gear, planetary gears, an internal gear, and a planetary carrier. For example, in the reducer GS, the internal gear (also called the "internal gear ring") is fixed to the cylinder housing HGc. The sun gear (also called the "sun gear") is fixed to the motor shaft SM, and the first rotational power Tm from the electric motor MT is input to the sun gear. Furthermore, the planetary carrier of the reducer GS is fixed to the rotating component BK, and the second rotational power Tn is output from the planetary carrier to the conversion mechanism GH.

[0066] The conversion mechanism GH consists of a rotating component BK that performs rotary motion and a linear component BD that performs linear motion. In the conversion mechanism GH, a second rotary power Tn output from the reducer GS is input to the rotating component BK. Furthermore, the second rotary power Tn input to the rotating component BK is converted into the linear power Fn of the linear component BD. The conversion mechanism GH is also called a "rotary / linear conversion mechanism".

[0067] For example, a ball screw is used as the conversion mechanism GH. Specifically, in the conversion mechanism GH, the rotating component BK, which is a shaft member, is fixed to the output shaft of the reducer GS. The rotating component BK is inserted into the linearly moving component BD, which has a cylindrical shape. A ball screw groove Mzk is formed on the outer peripheral surface Mok of the rotating component BK. Similarly, a ball screw groove Mzd is formed on the inner peripheral surface Mid of the linearly moving component BD. Multiple balls BL (steel balls) are embedded in the ball screw grooves Mzk and Mzd (refer to the discharge part XGH above).

[0068] In the conversion mechanism GH, the component with a threaded groove on its outer circumferential surface is called the "inner component." Conversely, the component with a threaded groove on its inner circumferential surface is called the "outer component." Furthermore, the outer component is configured to cover the inner component, and the threaded grooves of the inner component engage with the threaded grooves of the outer component. Specifically, in the ball screw mechanism, the two threaded grooves engage via multiple balls BL.

[0069] In the ball screw mechanism used as the conversion mechanism GH, the ball screw shaft (inner component, also called the "shaft component") is a rotating component BK, and the ball screw nut (outer component, also called the "nut component") is a linearly acting component BD. In this configuration, a threaded groove Mzk is formed on the outer circumferential surface Mok of the rotating component BK (inner component), and a threaded groove Mzd is formed on the inner circumferential surface Mid of the linearly acting component BD (outer component). Furthermore, the outer circumferential groove Mzk and the inner circumferential groove Mzd engage via balls BL.

[0070] In the direct-acting component BD, a flange portion Fd is provided at the end on the side away from the control cylinder CC (specifically, the control chamber Rc). The flange portion Fd extends radially Hk from the end of the cylindrical direct-acting component BD in a flange shape. A cutout is formed in the flange portion Fd. This cutout engages with the anti-rotation component MD.

[0071] An anti-rotation component MD is fixed to the cylinder housing HGc. For example, the anti-rotation component MD is a long, thin rod-shaped component (e.g., a pin component). In the housing HG, on the side of the direct-acting component BD away from the rotation axis Jk, a plurality of holes are provided at equal intervals around the rotation axis Jk. The anti-rotation component MD is inserted into and fixed in each of the plurality of holes. A semi-circular slit is provided on the flange portion Fd of the direct-acting component BD. Moreover, by engaging with the anti-rotation component MD through this slit, rotational movement about the rotation axis Jk is prevented in the direct-acting component BD. Thus, if the rotating component BK is rotated, the direct-acting component BD moves along the axial direction Hj (forward direction Ha or backward direction Hb).

[0072] A control piston NC is inserted into a control cylinder CC formed in a cylinder housing HGc. Specifically, the control piston NC consists of a bottom Btn (also called the "first bottom") and a cylindrical portion Enn (also called the "first cylindrical portion"). That is, the control piston NC has a cylindrical shape (cup shape) with a bottom Btn. A control chamber Rc (hydraulic chamber) is formed inside the control cylinder CC by the insertion of the control piston NC (especially the first bottom Btn).

[0073] 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 sealing components SL. The two sealing components SL are embedded in a sealing groove formed on the inner peripheral surface Mic of the control cylinder CC. Between the two sealing grooves, a through-hole (not shown, also referred to as the "shell hole") is provided in the cylinder housing HGc, leading to the control cylinder CC. The shell hole connects to the main reservoir RV via the replenishment path HH. A through-hole (not shown, also referred to as the "piston hole") is provided in the control piston NC, extending from the outer peripheral surface Mon to the bottom Btn, to connect the shell hole to the control chamber Rc.

[0074] The intermediate component BE is positioned axially Hj between the linearly driven component BD and the control piston NC. The intermediate component BE transmits power between the linearly driven component BD and the control piston NC. The linear power Fn from the linearly driven component BD is transmitted to the control piston NC via the intermediate component BE. Thus, the linearly driven component BD, the intermediate component BE, and the control piston NC can move as a unit in the forward direction Ha. Furthermore, the linearly driven component BD and the control piston NC are fixed by an anti-detachment component ND, ensuring that the linearly driven component BD, the intermediate component BE, and the control piston NC can also move as a unit when returning in the backward direction Hb.

[0075] Although the control piston NC is sealed relative to the control cylinder CC by the sealing member SL, if axial misalignment occurs (especially the misalignment of the direction of the linear power Fn with the direction of movement of the control piston NC), the contact between the outer peripheral surface Mon of the control piston NC and the sealing member SL becomes uneven. This results in reduced sealing performance and uneven wear of the sealing member SL. To suppress the effects of axial misalignment of the control piston NC (i.e., reduced sealing performance and uneven wear of the sealing member SL), an intermediate member BE is provided in the power transmission path from the linear actuator BD to the control piston NC.

[0076] The intermediate component BE consists of a bottom Bte (also called the "second bottom") and a cylindrical portion Ene (also called the "second cylindrical portion"). Similar to the control piston NC, the intermediate component BE has a cylindrical shape (i.e., a cup shape) with the second bottom Bte. Furthermore, the intermediate component BE is housed inside the control piston NC. That is, the control piston NC and the intermediate component BE are nested. This structure is called a "nested structure." In the nested structure, the control chamber Rc is sealed by the sliding of the outer control piston NC against the sealing component SL, and the influence of axial misalignment is compensated by the inner intermediate component BE.

[0077] A through-hole Ae (also called a "vent") is provided in the intermediate component BE (particularly the cylindrical portion Ene). Depending on the movement of the linear component BD, the rotating component BK enters and exits from the inside of the intermediate component BE. Specifically, when the linear component BD moves in the forward direction Ha (i.e., when the servo pressure Pc increases), the rotating component BK gradually exits from the interior of the intermediate component BE. Conversely, when the linear component BD moves in the backward direction Hb (i.e., when the servo pressure Pc decreases), the rotating component BK gradually enters the interior of the intermediate component BE. In other words, as the linear component BD moves, the volume of the gas (e.g., air) present inside the intermediate component BE changes, thus causing a change in the gas pressure inside the intermediate component BE. If a negative pressure is generated inside the intermediate component BE, it may cause the lubricant (e.g., grease) in the conversion mechanism GH to be drawn out. The vent Ae (e.g., a circular hole) is provided to allow the gas to move easily between the inside and outside of the intermediate component BE. The vent Ae may also be provided at the contact point between the intermediate component BE and the linear component BD. In this configuration, a cut is formed at the end of the intermediate component BE as a vent Ae.

[0078] ≪Adjusting the Servo PLC≫

[0079] In the braking control device SC, the wheel pressure Pw is adjusted by the servo pressure Pc, which is the output of the hydraulic generation unit PS. In the hydraulic generation unit PS, the rotational power Tm (i.e., shaft torque) of the electric motor MT is converted into the linear power Fn (i.e., thrust) of the direct-acting component BD (resulting in the control piston NC) via the conversion mechanism GH. Furthermore, the linear power Fn moves the control piston NC, thereby generating and adjusting the servo pressure Pc. A servo pressure sensor PC is installed in the hydraulic generation unit PS to detect the servo pressure Pc.

[0080] The conversion mechanism GH can perform both conversions from rotary motion to linear motion and from linear motion to rotary motion. In the operation of the conversion mechanism GH, the former is called "forward motion," and the latter is called "reverse motion." Therefore, the movement of the control piston NC is determined based on the relationship between the torque output from the electric motor MT (also called "forward motion torque Qmt") and the torque input to the electric motor MT through the servo pressure Pc (also called "reverse motion torque Qpc"). The adjustment (increase or decrease) of the servo pressure Pc will be explained below.

[0081] (Increase in servo voltage Pc)

[0082] exist Figure 2 In the diagram, at the upper part of the rotation axis Jk, the hydraulic generating unit PS is shown in a state where no servo pressure Pc is generated. In this state, the control chamber Rc is connected to the main reservoir RV via the housing hole and the piston hole, and the servo pressure Pc is "0 (atmospheric pressure)". The positions of the direct-acting components BD, control piston NC, etc., in this state are called the "initial positions". In the initial position, the control piston NC is displaced to its maximum extent in the backward direction Hb, and the volume of the control chamber Rc is at its maximum.

[0083] As described above, the control piston NC and the intermediate component BE have a bottomed cylindrical shape (cup shape) and are nested, so that the intermediate component BE is housed inside the control piston NC. Furthermore, with the control piston NC in its initial position, the rotating component BK enters the interior of the intermediate component BE. This structure allows for miniaturization of the axial dimension Hj (also known as the "shaft length") in the hydraulic generating unit PS.

[0084] If the braking requirement value (a state quantity displaying the required braking force, such as the operating displacement Sp of the braking operation component BP) increases, the target pressure Pt increases from "0". The target pressure Pt is the target value corresponding to the servo pressure Pc (actual value). The target pressure Pt increases with the increase of the braking requirement value. As the target pressure Pt increases, the forward operating torque Qmt is greater than the reverse operating torque Qpc, and the electric motor MT rotates in the forward direction Hs. In other words, the electric motor MT generates rotational power Tm in the forward direction Hs. The rotational power Tm is transmitted to the conversion mechanism GH via the reducer GS and output as the linear power Fn of the direct-acting component BD. Moreover, the direct-acting component BD presses the intermediate component BE, and the intermediate component BE presses the control piston NC. As a result, the control piston NC moves in the forward direction Ha (the direction in which the volume of the control chamber Rc decreases).

[0085] This movement first disconnects the connection between the control chamber Rc and the main reservoir RV. If the control piston NC moves further in the forward direction Ha, the servo pressure Pc (the internal pressure of the control chamber Rc) increases 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.

[0086] (Holding the servo pressure Pc)

[0087] If the braking requirement is constant, the target pressure Pt is maintained. The forward operating torque Qmt is equal to the reverse operating torque Qpc, and the rotation of the electric motor MT stops (i.e., the rotational speed of the electric motor MT becomes "0"). Since the movement of the control piston NC stops, the servo pressure Pc is maintained constant (see reference). Figure 2 (The lower part of the rotation axis Jk).

[0088] (Reduction of servo pressure PC)

[0089] If the braking requirement decreases, the target pressure Pt decreases. Consequently, the rotational power Tm of the electric motor MT decreases. The reverse operating torque Qpc based on the servo pressure Pc is greater than the forward operating torque Qmt based on the electric motor MT, causing the electric motor MT to rotate in the reverse direction Hg. The control piston NC moves in the backward direction Hb, increasing the volume of the control chamber Rc. The brake fluid BF, which has moved to the servo chamber Ru and the rear wheel cylinder CWr, returns towards the control chamber Rc, thus reducing the servo pressure Pc.

[0090] <Compensation for the Influence of Intermediate Component BE on Shaft Offset>

[0091] Reference Figure 3 A partial sectional view is provided to illustrate the suppression of the influence of the intermediate component BE on axial offset. Here, the suppression of the influence caused by axial offset is referred to as "axial offset compensation." Figure 3 This illustrates a situation where there is no axial offset, and the rotation axis Jk of the rotating component BK, the central axis Je of the intermediate component BE, 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.

[0092] ≪Axis Offset≫

[0093] First, let's explain shaft offset. In power transmission, it is desirable for the axes Jk, Jn, and Jc to be aligned in a straight line. However, since the conversion mechanism GH, control piston NC, and control cylinder CC are independent components, their axes Jk, Jn, and Jc may deviate from this straight line. This offset of axes Jk, Jn, and Jc is called "shaft offset." Shaft offset is an eccentricity (center misalignment) between axes, also known as "misalignment."

[0094] For example, there are two axes that intersect each other but have an angle (i.e., insufficient parallelism). Such axis offset is called "angular offset (or angular error)". Additionally, there are two axes that are offset parallel to each other. Such axis offset is called "parallel offset (or parallel error)". Typically, axis offset is a combination of angular and parallel offsets.

[0095] If shaft misalignment (center misalignment) occurs, as described above, the contact between the outer circumferential surface Mon of the control piston NC and the sealing component SL becomes uneven, raising concerns about reduced sealing performance and uneven wear of the sealing component SL. Furthermore, the load in the conversion mechanism GH also becomes uneven, potentially leading to uneven wear of the ball bearing components BL, threaded grooves Mzk and Mzd, etc. An intermediate component BE is provided in the hydraulic generation unit PS to compensate for shaft misalignment.

[0096] ≪Axis Offset Compensation Mechanism≫

[0097] The shaft offset compensation mechanism, consisting of a conversion mechanism GH, a control piston NC, and an intermediate component BE, will be described. The conversion mechanism GH consists of a rotating component BK and a linear component BD. The rotating component BK is held in a state where its translational motion (linear motion in the axial direction Hj) is restricted relative to the housing HG, but it is capable of rotational motion. Conversely, the linear component BD is held in a state where its rotational motion is restricted relative to the housing HG, but it is capable of translational motion. Thus, the conversion mechanism GH outputs the rotational power Tm input to the rotating component BK as the linear power Fn of the linear component BD. Here, in the conversion mechanism GH, the linear component BD is configured to cover the rotating component BK. For example, in a configuration using a ball screw mechanism as the conversion mechanism GH, the rotating component BK is a ball screw shaft, and the linear component BD is a ball screw nut.

[0098] A flange Fd is provided at the end of the linear actuator BD (specifically, the end away from the bottom surface Mbc of the control cylinder CC, or the end away from the bottom Btn of the control piston NC). A cut is formed on the outer periphery of the flange Fd. This cut engages with an anti-rotation component MD. The anti-rotation component MD is fixed to the housing HG. By preventing the rotational movement of the linear actuator BD relative to the housing HG, the rotational movement of the rotating component BK can be converted into the linear movement of the linear actuator BD.

[0099] A control piston NC is inserted into a control cylinder CC formed within a housing HG. The control piston NC is a bottomed cylindrical shape (cup shape), consisting of a first bottom Btn and a first cylindrical portion Enn. Two sealing grooves are formed on the inner circumferential surface Mic of the control cylinder CC. Sealing members SL are embedded in each of these grooves. The outer circumferential surface Mon of the cylindrical portion Enn and the inner circumferential surface Mic of the control cylinder CC are sealed by the sealing members SL. A control chamber Rc (hydraulic chamber) is formed within the control cylinder CC via the control piston NC (particularly the bottom Btn). Furthermore, a plane perpendicular to the central axis Jn of the control piston NC (i.e., the central axis of the first cylindrical portion Enn) is formed on the inner bottom surface Mtn of the first bottom Btn.

[0100] An annular groove is formed on the inner circumferential surface Min of the cylindrical portion Enn of the control piston NC. Additionally, an annular groove is also formed on the outer circumferential surface Mod of the linear actuator BD. Anti-disengagement components ND (e.g., retaining rings) are embedded in these grooves. The anti-disengagement components ND limit the relative displacement between the control piston NC and the linear actuator BD, preventing them from completely separating. Furthermore, the anti-disengagement components ND have gaps (slots) relative to the annular grooves in both the axial direction Hj and the radial direction Hk. Therefore, the control piston NC and the linear actuator BD can move relative to each other within the range of these gaps, regardless of whether they are in the axial direction Hj or the radial direction Hk.

[0101] The intermediate component BE is positioned between the control piston NC and the direct-acting component BD. The intermediate component BE, like the control piston NC, is a bottomed cylindrical shape (cup shape), consisting of a second bottom portion Bte and a second cylindrical portion Ene. In the nested structure (i.e., the intermediate component BE is disposed inside the control piston NC), the bottom portion Btn (first bottom) of the control piston NC and the bottom portion Bte (second bottom) of the intermediate component BE are in sliding contact. Here, "sliding" refers to the action of the two components sliding and moving simultaneously while in contact.

[0102] In detail, sliding is possible between the outer bottom surface Mpe (also called the "pressing surface") of the intermediate component BE and the inner bottom surface Mtn (also called the "pressure-bearing surface") of the control piston NC. A spherical protrusion with radius Rq is formed on the pressing surface Mpe (equivalent to an "end face") of the intermediate component BE. Furthermore, a fillet with radius Rp (also called an "R-corner") is formed at the location in the intermediate component BE where the pressing surface Mpe connects to the outer peripheral surface Moe of the cylindrical portion Ene (also called the "corner"). That is, a fillet is provided at the corner of the bottom Bte of the intermediate component BE. Here, the radius Rq of the convex spherical surface is particularly large relative to the radius Rp of the fillet. The part where the pressing surface Mpe (outer bottom surface) of the intermediate component BE contacts the pressure-bearing surface Mtn (inner bottom surface) of the control piston NC is called the "first sliding part Sda".

[0103] The end face Mqe (also called the "intermediate end face") of the cylindrical portion Ene of the intermediate component BE contacts the end face Mpd (also called the "direct-moving end face") of the linear component BD in a sliding state. For example, the intermediate end face Mqe (equivalent to the "other end face") is a plane perpendicular to the central axis Je of the intermediate component BE (i.e., the central axis of the second cylindrical portion Ene). The direct-moving end face Mpd is a plane perpendicular to the rotation axis Jk. Therefore, the direct-moving end face Mpd and the intermediate end face Mqe contact on a plane perpendicular to the axial direction Hj and parallel to the radial direction Hk. Here, the part where the intermediate end face Mqe of the intermediate component BE contacts the direct-moving end face Mpd of the linear component BD is called the "second sliding portion Sdb".

[0104] The configuration of the conversion mechanism GH, the control piston NC, and the intermediate component BE can be summarized as follows: The intermediate component BE is housed inside the control piston NC. The intermediate component BE is located between the linear actuator BD (specifically, the linear end face Mpd) and the control piston NC (specifically, the pressure surface Mtn). When the servo pressure Pc increases, the intermediate end face Mqe (plane) is pushed forward in the forward direction Ha by the linear end face Mpd (plane), thereby pushing the pressure surface Mtn (plane) in the forward direction Ha by the pressing surface Mpe (convex surface). This causes the control piston NC, the intermediate component BE, and the linear actuator BD to move in the forward direction Ha. Conversely, when the servo pressure Pc decreases, the pressing surface Mpe is pushed backward in the backward direction Hb by the pressure surface Mtn, thereby pushing the linear end face Mpd in the backward direction Hb by the intermediate end face Mqe. This causes the control piston NC, the intermediate component BE, and the linear actuator BD to move in the backward direction Hb. Here, the intermediate component BE has two parts (i.e., the first and second sliding parts Sda and Sdb) that are capable of sliding relative to the control piston NC and the direct-acting component BD.

[0105] ≪Axis Offset Compensation≫

[0106] The operation of the shaft misalignment compensation mechanism is explained. It compensates for the effects of shaft misalignment by allowing sliding in the radial direction (Hk) between the power transmission components (BD, BE, NC, etc.) and by allowing the intermediate component BE to rotate during contact between the control piston NC and the intermediate component BE. Although the control piston NC and the intermediate component BE are configured in a nested state, there is a gap (also called a "nesting gap") between them in the radial direction (Hk). This nesting gap allows sliding between the components in the hydraulic generation unit PS.

[0107] In the first sliding section Sda, the pressure surface Mtn of the control piston NC (e.g., a plane perpendicular to the central axis Jn of the first cylindrical section Enn) contacts the pressing surface Mpe of the intermediate component BE (e.g., a convex surface). The pressure surface Mtn and the pressing surface Mpe can be displaced relative to each other in the radial direction Hk within the gap (i.e., nested gap) between the inner circumferential surface Min of the control piston NC and the outer circumferential surface Moe of the intermediate component BE. In addition, since the pressing surface Mpe is a convex surface (e.g., a spherical surface), it can rotate and tilt relative to each other about the contact point between the pressure surface Mtn and the pressing surface Mpe. This rotational motion is called "oscillation". By oscillation (tilt) and sliding (slip) at the first sliding section Sda, the effects of axial offset (angular offset and parallel offset) of the control piston NC, etc., are suppressed. Furthermore, if the tilt (i.e., the degree of oscillation) of the pressure surface Mtn and the pressing surface Mpe increases, the pressure surface Mtn contacts the corner of the intermediate component BE. Because a rounded corner (chamfered corner) is provided at this corner, the contact pressure between the pressure surface Mtn and the pressing surface Mpe can be suppressed even if the angle deviation is too large.

[0108] In the second sliding section Sdb, the direct-acting end face Mpd of the direct-acting component BD (e.g., a plane perpendicular to the rotation axis Jk of the rotating component BK) contacts the intermediate end face Mqe of the intermediate component BE (e.g., a plane perpendicular to the central axis Je of the second cylindrical section Ene). During this contact, the direct-acting end face Mpd and the intermediate end face Mqe can slide relative to each other. Therefore, the direct-acting end face Mpd and the intermediate end face Mqe can be radially displaced relative to each other within the gap (i.e., the nested gap) between the inner circumferential surface Min of the control piston NC and the outer circumferential surface Moe of the intermediate component BE.

[0109] The control piston NC is held in the housing HG by the sealing member SL. The conversion mechanism GH is also held in the housing HG by bearings (e.g., bearings). The intermediate member BE is not directly held in the housing HG, but functions as a floating joint. Specifically, the intermediate member BE can slide and move parallel to both the control piston NC and the direct-acting member BD in the radial direction Hk. This appropriately suppresses the effect of parallel misalignment. Furthermore, since the intermediate member BE can oscillate relative to the control piston NC, the effect of angular misalignment can be appropriately suppressed. In addition, the presence of the second sliding part Sdb does not hinder sliding and oscillation at the first sliding part Sda. That is, because sliding / oscillation is easily generated, the compensation effect for angular misalignment can be improved. In the hydraulic generating unit PS, by providing two sliding parts Sda and Sdb through the intermediate member BE, not only the effect of parallel misalignment can be suppressed, but also the effect of angular misalignment can be appropriately compensated.

[0110] Positioning of intermediate component BE: First example of its composition

[0111] A first configuration example relating to the positioning of the intermediate component BE relative to the control piston NC will be described. In an axial offset compensation mechanism, the larger the nesting gap, the greater the effect of axial offset compensation. However, if the nesting gap is set too large, it becomes difficult to position the intermediate component BE when the linear power Fn is small. Therefore, in the hydraulic generation unit PS, in the nesting gap between the inner circumferential surface Min of the cylindrical portion Enn (first cylindrical portion) of the control piston NC and the outer circumferential surface Moe of the cylindrical portion Ene (second cylindrical portion) of the intermediate component BE, the nesting gap Ska near the bottom Btn (first bottom) of the control piston NC is made narrower than the nesting gap Skb far from the first bottom Btn. Here, the nesting gap Ska near the bottom Btn is referred to as the "approaching gap," and the nesting gap Skb far from the bottom Btn is referred to as the "far-away gap." Specifically, on a cross-section perpendicular to the central axis Jn, the difference between the inner diameter of the inner circumferential surface Min of the control piston NC and the outer diameter of the outer circumferential surface Moe of the intermediate component BE at a location relatively close to the contact area of ​​the first and second bottoms Btn and Bte is approximately the gap Ska. Conversely, on a cross-section perpendicular to the central axis Jn, the difference between the inner diameter of the inner circumferential surface Min of the control piston NC and the outer diameter of the outer circumferential surface Moe of the intermediate component BE at a location relatively far from the aforementioned contact area is approximately the gap Skb.

[0112] The size of the inner diameter (i.e., the diameter of the inner circumferential surface Min) of the cylindrical portion Enn of the control piston NC is formed in two stages, thereby setting the approach gap Ska and the distance from the gap Skb. Specifically, the inner circumferential surface Min of the portion near the bottom Btn (more specifically, the region from the contact portion of the pressure surface Mtn and the pressing surface Mpe to a predetermined distance La) is formed with a diameter Da (also called the "approach inner diameter"). Moreover, the inner circumferential surface Min of the portion away from the bottom Btn (more specifically, the region from the contact portion of the pressure surface Mtn and the pressing surface Mpe to a predetermined distance La or more) is formed with a diameter Db (also called the "distance from the inner diameter"). Furthermore, although the approach inner diameter Da is larger than the outer diameter De (i.e., the diameter of the outer circumferential surface Moe) of the cylindrical portion Ene of the intermediate component BE, it is smaller than the distance from the inner diameter Db by a predetermined value rx (i.e., "De < Da < Db"). Here, the outer diameter De of the cylindrical portion Ene of the intermediate component BE is constant.

[0113] The intermediate component BE is configured to be inserted into the control piston NC and to contact the bottom Btn (specifically, the pressure surface Mtn) of the control piston NC. Therefore, the approach gap Ska in the region from the pressure surface Mtn to a predetermined distance La is smaller than the distant gap Skb in the region separated from the pressure surface Mtn by at least a predetermined distance La. In other words, in the hydraulic generating unit PS, the approach gap Ska is set to be narrower than the distant gap Skb in the nested gaps. This improves the positioning accuracy of the intermediate component BE relative to the control piston NC in the hydraulic generating unit PS.

[0114] To compensate for the effects of parallel offset, the intermediate component BE can move in the radial direction Hk at least close to the distance of the gap Ska. Furthermore, it can also compensate for parallel offset between the intermediate component BE and the rotating component BK. In addition, to compensate for the effects of angular offset, the intermediate component BE can oscillate around the pressing surface Mpe. During this oscillation, the amount of movement in the arc direction is small near its center (i.e., the contact area of ​​the first and second bottom parts Btn and Bte), but the amount of movement in the arc direction increases further away from the center. In the hydraulic generating unit PS, the distance from the gap Skb is relatively greater than the distance from the gap Ska, thus ensuring a sufficient rotation angle (also called the "oscillation angle") during the oscillation (rotational motion). In other words, the positioning accuracy of the intermediate component BE can be improved in the hydraulic generating unit PS by appropriately compensating for the effects of axial offset (the combination of parallel offset and angular offset).

[0115] Suppression of poor lubrication caused by negative pressure

[0116] In the configuration employing a nested structure, the lubrication of the conversion mechanism GH will be ensured. In the hydraulic generation unit PS, the axial Hj dimension is shortened by "using a cup shape for the control piston NC and the intermediate part BE, and making them a nested structure," and "accommodating the rotating part BK inside the intermediate part BE." However, since the rotating part BK moves in and out of the cylindrical portion Ene of the intermediate part BE, pressure fluctuations occur within the cylindrical portion Ene. These pressure fluctuations can create negative pressure, leading to loss of lubricant (e.g., grease) that lubricates the conversion mechanism BH, etc. Furthermore, improving the positioning accuracy of the intermediate part BE increases the tightness of the contact between the direct-acting end face Mpd and the intermediate end face Mqe.

[0117] To suppress the reduction of lubricant (grease, etc.) caused by negative pressure, a vent hole Ae (e.g., a circular hole) is provided in the intermediate part BE (particularly the cylindrical part Ene). When the servo pressure Pc is increased, gas (e.g., air) flows from the outside to the inside of the intermediate part BE through the vent hole Ae. Conversely, when the servo pressure Pc is decreased, gas flows from the inside to the outside of the intermediate part BE through the vent hole Ae. Because the gas can move freely between the inside and outside of the intermediate part BE through the vent hole Ae, poor lubrication caused by lubricant ejection can be suppressed. Furthermore, since the vent hole Ae is for the purpose of gas movement, a vent hole Ae (e.g., a notch) can also be provided at the contact surface between the intermediate part BE and the direct-acting part BD.

[0118] <Positioning of intermediate component BE: Second configuration example>

[0119] Reference Figure 4 The partial cross-sectional view illustrates a second configuration example relating to the positioning of the intermediate component BE. In the first configuration example, the inner diameter of the cylindrical portion Enn of the control piston NC is formed in two stages. Instead, in the second configuration example, the outer diameter (i.e., the diameter of the outer circumferential surface Moe) of the cylindrical portion Ene of the intermediate component BE is formed in two stages. The following description focuses on the differences.

[0120] The outer peripheral surface Moe of the intermediate component BE, near the bottom Bte (specifically, the region from the contact point of the first and second bottoms Btn and Bte to a predetermined distance Lc), is formed with a diameter Dc (also called the "approach outer diameter"). Conversely, the outer peripheral surface Moe of the region farther from the bottom Bte (specifically, the region more than a predetermined distance Lc from the contact point of the first and second bottoms Btn and Bte) is formed with a diameter Dd (also called the "distant outer diameter"). Furthermore, while the approach outer diameter Dc is smaller than the inner diameter Dn of the cylindrical portion Enn of the control piston NC (i.e., the diameter of the inner peripheral surface Min), it is larger than the distant outer diameter Dd by a predetermined value rz (i.e., "Dn > Dc > Dd"). Here, the inner diameter Dn of the cylindrical portion Enn of the control piston NC is constant.

[0121] Similar to the first configuration, in the second configuration, the approach gap Ska (i.e., the nested gap near the first bottom Btn) in the region from the pressure surface Mtn (=Mpe) to a predetermined distance Lc is also smaller than the distant gap Skb (i.e., the nested gap away from the first bottom Btn) in the region separated from the pressure surface Mtn by at least a predetermined distance Lc. In other words, in the hydraulic generating unit PS, the approach gap Ska is set to be narrower than the distant gap Skb in the nested gaps, thus achieving the same effect as the first configuration (improved positioning accuracy and ensured axis offset compensation).

[0122] <Other implementations of the hydraulic generation unit PS, etc.>

[0123] The following describes other embodiments of the hydraulic generating unit PS. In other embodiments, the hydraulic generating unit PS achieves the same effects as described above (axis offset compensation, improved positioning accuracy of the intermediate component BE, shortened shaft length of the hydraulic generating unit PS, and ensured lubrication of the conversion mechanism GH, etc.).

[0124] In the aforementioned embodiment of the hydraulic generating unit PS, a ball screw is used as the conversion mechanism GH. Alternatively, a sliding screw (e.g., a trapezoidal screw) can be used instead of a ball screw in the conversion mechanism GH. In the configuration using a sliding screw mechanism, an external thread is formed on the inner component as a thread groove. An internal thread is formed on the outer component as a thread groove. Furthermore, the external and internal threads directly mesh. Reverse motion is also generated in the conversion mechanism GH using a sliding screw.

[0125] In the aforementioned embodiment of the hydraulic generating unit PS, a configuration is adopted in which axis Jm and axes Jc, Jn, and Jk are arranged in a straight line. This configuration is called a "coaxial configuration (or, single-axis configuration)" because axis Jm and axis Jc are coaxial. In a coaxial configuration, the reducer GS uses a mechanism where the rotation axis of the input shaft and the rotation axis of the output shaft are coaxial (e.g., a planetary gear mechanism). Alternatively, a "different-axis configuration (or, dual-axis configuration)" can be adopted where axis Jm and axes Jc, Jn, and Jk are on different axes. In a different-axis configuration, the reducer GS uses a mechanism where the rotation axis of the input shaft and the rotation axis of the output shaft are different (e.g., a gear train). In a different-axis configuration, axis Jm and axes Jc, Jn, and Jk are different axes but arranged parallel to each other. Furthermore, in a different-axis configuration, axes Jc, Jn, and Jk are coaxial.

[0126] In the above-described embodiment of the hydraulic generating unit PS, the approach gap Ska is narrower than the distance gap Skb by either "setting the inner diameters Da and Db of the control piston NC in two stages (refer to the first configuration example)" or "setting the outer diameters Dc and Dd of the intermediate component BE in two stages (refer to the second configuration example)". Alternatively, the first and second configuration examples can be combined. Therefore, in the hydraulic generating unit PS, "Ska < Skb" is achieved by at least one of "setting the inner diameters Da and Db of the control piston NC in two stages" and "setting the outer diameters Dc and Dd of the intermediate component BE in two stages".

[0127] In the above-described embodiment of the hydraulic generating unit PS, the "inner diameters Da and Db of the control piston NC" and / or the "outer diameters Dc and Dd of the intermediate component BE" are set in two stages within the nested gaps. Alternatively, these inner and / or outer diameters can be set in multiple stages. Or, they can be set to change gradually without stages. In summary, in the hydraulic generating unit PS, the gap Ska is narrower than the gap Skb.

[0128] In the above-described embodiment of the hydraulic generating unit PS, an example is shown where the end face Mpe of the intermediate component BE that contacts the first bottom Btn is convex, and the end face Mqe of the intermediate component BE that contacts the direct-acting component BD is planar. In the hydraulic generating unit PS, it is sufficient that at least one of the end face Mpe of the intermediate component BE that contacts the first bottom Btn and the end face Mqe of the intermediate component BE that contacts the direct-acting component BD is convex. In other words, in the hydraulic generating unit PS, "one of the end face Mpe of the intermediate component BE that contacts the first bottom Btn and the end face Mqe of the intermediate component BE that contacts the direct-acting component BD is convex and the other is planar," or "both the end face Mpe of the intermediate component BE that contacts the first bottom Btn and the end face Mqe of the intermediate component BE that contacts the direct-acting component BD are convex." By making at least one of the end faces Mpe and Mqe on both sides of the intermediate component BE convex (e.g., convex spherical surface), oscillation is easily generated. This improves the compensation effect for axial misalignment.

[0129] The aforementioned brake control device SC is applied to vehicles that have a regenerative braking device KG in the front wheel WHf and perform regenerative coordination control. In vehicles performing regenerative coordination control, the regenerative braking device KG only needs to be installed in at least one of the front wheel WHf and the rear wheel WHr. Furthermore, the brake control device SC can also be applied to vehicles that omit the regenerative braking device KG and do not perform regenerative coordination control. In other words, the brake control device SC is independent of the presence or absence of regenerative coordination control and can be applied to various types of vehicles.

[0130] In the above-described configuration of the brake control device SC, a single-cylinder master cylinder CM is used. The brake control device SC can also employ a tandem master cylinder CM. In this configuration, two main chambers Rm are formed inside the CM. Furthermore, a servo pressure Pc is supplied to the servo chamber Ru from the hydraulic generation unit PS, and wheel pressure Pw is supplied to the wheel cylinder CW from the main chambers Rm. In this configuration, the brake control device SC can also employ not only a front-rear system but also a diagonal (also called "X-type") system, serving as a dual-system brake system. In the diagonal brake control device SC, one of the two main chambers Rm is connected to the right front wheel cylinder and the left rear wheel cylinder. The other of the two main chambers Rm is connected to the left front wheel cylinder and the right rear wheel cylinder.

[0131] In the aforementioned configuration example of the brake control device SC, the supply pressure Pm is output via the master cylinder CM in the first brake unit SA. That is, the application unit AP and the hydraulic generation unit PS are connected in series along the hydraulic transmission path, and the servo pressure Pc supplied from the hydraulic generation unit PS is transmitted as the supply pressure Pm via the master piston NM. Alternatively, the application unit AP and the hydraulic generation unit PS can be connected in parallel. Specifically, the application unit AP (especially the master cylinder CM) and the hydraulic generation unit PS are each directly connected to the second actuator YB. Furthermore, either the connection between the hydraulic generation unit PS and the second actuator YB or the connection between the application unit AP and the second actuator YB can be selected by opening and closing a solenoid valve (called a "switching valve"). When the former is selected, the servo pressure Pc generated by the hydraulic generation unit PS is directly output as the supply pressure Pm without passing through the application unit AP. In this case, the application unit AP is connected to the stroke simulator SS, and the operating force of the brake operating component BP is generated by the stroke simulator SS. On the other hand, if the latter option is selected, the hydraulic pressure of the main chamber Rm generated by the operation of the brake operating component BP is output as the supply pressure Pm. At this time, the application unit AP is disconnected from the simulator SS.

[0132] <Summary of Implementation Methods>

[0133] The implementation method of the hydraulic generating unit PS (hydraulic generating device) is summarized. The hydraulic generating unit PS is used in the brake control device SC to control the braking force of the wheel WH by adjusting the wheel pressure Pw of the wheel cylinder CW.

[0134] The hydraulic generation unit PS includes an electric motor MT, a conversion mechanism GH, a control piston NC (equivalent to a "piston"), and an intermediate component BE. The electric motor MT outputs rotational power Tm. The conversion mechanism GH converts the rotational power Tm input to the rotating component BK into linear power Fn for the linear component BD. The control piston NC is inserted into the control cylinder CC (equivalent to a "cylinder"). Furthermore, the control piston NC moves via the linear power Fn, thereby increasing the hydraulic pressure Pc (servo pressure) of the control cylinder CC. Specifically, the control piston NC increases the servo pressure Pc by moving in the forward direction Ha (i.e., towards the bottom surface Mbc of the control cylinder CC).

[0135] In the hydraulic generating unit PS, the control piston NC has a first bottom Btn and a first cylindrical portion Enn. Furthermore, the intermediate component BE has a second cylindrical portion Ene and is inserted into the first cylindrical portion Enn. Here, in the gap (nested gap) between the inner circumferential surface Min of the first cylindrical portion Enn and the outer circumferential surface Moe of the second cylindrical portion Ene, the gap Ska (approach gap) on the side closer to the first bottom Btn is narrower than the gap Skb (away gap) on the side farther from the first bottom Btn. Moreover, at least one of the end face Mpe (pressing surface) of the intermediate component BE that contacts the first bottom Btn and the end face Mqe (intermediate end face) of the intermediate component BE that contacts the direct-acting component BD is machined as a convex surface. For example, the pressing surface Mpe is convex, and the intermediate end face Mqe is flat.

[0136] The intermediate component BE (specifically, the pressing surface Mpe) contacts the bottom Btn (specifically, the pressure-bearing surface Mtn) of the control piston NC. By setting the approach gap Ska narrow, the intermediate component BE can be properly positioned relative to the control piston NC. Furthermore, the intermediate component BE can move parallel to the radial Hk by at least a distance close to the gap Ska, thus compensating for parallel offset. Additionally, parallel offset is also compensated between the intermediate component BE and the rotating component BK. Moreover, since "Skb > Ska", the swing angle centered on the pressing surface Mpe can be sufficiently ensured. Therefore, in addition to parallel offset, angular offset can also be appropriately compensated. That is, in the hydraulic generating unit PS, the positioning accuracy of the intermediate component BE can be improved while appropriately compensating for axial offset.

[0137] In the hydraulic generating unit PS, the rotating component BK can enter the second cylindrical section Ene. This shortens the axial length of the hydraulic generating unit PS. Furthermore, to reduce pressure changes in the gas within the intermediate component BE caused by volume changes, a vent Ae (circular hole, slit, etc.) is provided in the intermediate component BE. The vent Ae prevents gas expansion and compression, thus suppressing lubricant (grease) loss from the conversion mechanism GH and other components due to pressure fluctuations.

Claims

1. A hydraulic generating device comprising: an electric motor that outputs rotational power; a conversion mechanism that outputs the rotational power input to a rotating component as linear power for a direct-acting component; a piston inserted into a cylinder and moved by the linear power to increase the hydraulic pressure in the cylinder; and an intermediate component disposed between the direct-acting component and the piston, capable of sliding relative to the direct-acting component and the piston, wherein... The piston described above has a first bottom and a first cylindrical portion. The aforementioned intermediate component has a second cylindrical portion and is inserted into the aforementioned first cylindrical portion. In the gap between the inner circumferential surface of the first cylindrical portion and the outer circumferential surface of the second cylindrical portion, the gap near the first bottom is narrower than the gap away from the first bottom.

2. The hydraulic generating device according to claim 1, wherein, At least one of the end faces of the intermediate component that contacts the first bottom and the intermediate component that contacts the linear component is a convex surface.

3. The hydraulic generating device according to claim 1 or 2, wherein, The aforementioned rotating component can enter the aforementioned second cylindrical section.

4. The hydraulic generating device according to claim 3, wherein, The aforementioned second cylindrical section has a vent.

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