Feature acquisition device

Abstract

To acquire operation characteristics of a linear valve used as a holding valve in a mechanism which adjusts braking force.SOLUTION: A characteristic acquisition device includes: a power supply control unit (242) which controls supply of electric current to a linear valve (182); a first acquisition unit (244) which acquires a first liquid pressure in a liquid passage (14a) connecting a pressurization source with the linear valve; a second acquisition unit (245) which acquires a second liquid pressure in a liquid passage (14b) connecting the linear valve with wheel cylinders (17A, 17B); and a calculation part (246) which calculates operation characteristics on the basis of a value of the electric current and a difference between the first liquid pressure and the second liquid pressure.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a characteristic acquisition device.

Background Art

[0002] For example, as described in Patent Document 1, a hydraulic control device has been developed in which a linear solenoid valve (hereinafter referred to as a "linear valve") is adopted as a pressure increasing valve (also referred to as a "holding valve") in a mechanism for performing antilock brake control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, it is desired to establish a method for acquiring the operating characteristics of a linear valve used as a holding valve in a mechanism for adjusting braking force such as antilock brake control. One aspect of the present invention aims to enable the acquisition of the operating characteristics of a linear valve used as a holding valve in a mechanism for adjusting braking force.

Means for Solving the Problems

[0005] To solve the above problems, a characteristic acquisition device according to one aspect of the present invention is a characteristic acquisition device for calculating the operating characteristics of a normally open linear valve, which is provided in a fluid passage of brake fluid connecting a wheel cylinder and a pressurizing source that pressurizes the wheel cylinder, and which can suppress pressurization of the wheel cylinder by the pressurizing source by receiving an electric current, comprising: a power supply control unit that controls the supply of electric current to the linear valve; a first acquisition unit that acquires a first fluid pressure in a first fluid passage which constitutes a part of the fluid passage and connects the pressurizing source and the linear valve; a second acquisition unit that acquires a second fluid pressure in a second fluid passage which constitutes a part of the fluid passage and connects the linear valve and the wheel cylinder; and a calculation unit that calculates the operating characteristics based on the value of the electric current supplied to the linear valve and the fluid pressure difference between the first fluid pressure acquired by the first acquisition unit and the second fluid pressure acquired by the second acquisition unit. [Effects of the Invention]

[0006] According to one aspect of the present invention, the operating characteristics of a linear valve used as a retaining valve in a mechanism for adjusting braking force can be obtained. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows a schematic configuration of a braking mechanism that includes a retaining valve, the target of acquiring the operating characteristics of the characteristic acquisition device according to the first embodiment of the present invention. [Figure 2] This diagram shows the details of the adjustment unit provided by the mechanism. [Figure 3] This is a diagram showing a magnified view of a portion of the same unit. [Figure 4] This is a block diagram showing the configuration of a characteristic acquisition device according to the first embodiment of the present invention. [Figure 5] These graphs show the time-dependent changes in the first and second hydraulic pressures, and the time-dependent changes in the current supplied to the linear valve, as the device acquires its operating characteristics. [Figure 6] This graph shows the operating characteristics of the linear valve calculated by the device. [Figure 7]This is a block diagram showing the configuration of a characteristic acquisition device according to a second embodiment of the present invention. [Figure 8] This diagram illustrates the method for estimating the second hydraulic pressure using the same device. [Figure 9] This figure illustrates a method for estimating the second liquid volume characteristic necessary for estimating the second liquid pressure using a characteristic acquisition device according to a modified example of the same embodiment. [Modes for carrying out the invention]

[0008] <First Embodiment> The first embodiment of the present invention will be described in detail below.

[0009] [Brake mechanism] Before describing the characteristic acquisition device 2 according to this embodiment, an example of the braking mechanism 1 will be described. This braking mechanism 1 is installed in a vehicle and includes a retaining valve 182. This retaining valve 182 is the target of the characteristic acquisition device 2's acquisition of operating characteristics.

[0010] {Configuration of the braking mechanism} The braking mechanism 1 applies braking force to the multiple wheels FL, FR, RL, and RR of the vehicle. As shown in Figure 1, the braking mechanism 1 comprises a pressurizing unit 1A, an adjustment unit 1B, a drive circuit 1C (see Figure 4), and a control device (not shown). The drive circuit 1C supplies current to the pressurizing unit 1A and the adjustment unit 1B. The control device controls the pressurizing unit 1A, the adjustment unit 1B, and the drive circuit 1C. Note that Figure 1 shows the state when each part is in its initial position before braking operation.

[0011] [Pressurization unit] The pressure unit 1A includes a master reservoir 11 for storing brake fluid, a master cylinder 12, a stroke simulator 13, a plurality of liquid passages 14A, 14B, 14C, and 14D, a first on-off valve 15A, a second on-off valve 15B, an electric cylinder 16, a front-wheel wheel cylinder 17A, a rear-wheel wheel cylinder 17B, and an output pressure sensor Sc. Hereinafter, each part will be described with the left side in FIG. 1 being the front in the pressure unit 1A and the right side in FIG. 1 being the rear in the pressure unit 1A.

[0012] (Master cylinder) The master cylinder 12 supplies brake fluid to the adjustment unit 1B. The master cylinder 12 includes a main cylinder 121, an input cylinder 122, a master piston 123, an input piston 124, a master spring 125, and an input spring 126.

[0013] The main cylinder 121 has a bottom wall 121a, a first peripheral wall 121b, a second peripheral wall 121c, and a first annular wall 121d. The bottom wall 121a is substantially disc-shaped. The first peripheral wall 121b is cylindrical and extends along the axis L of the bottom wall 121a from the bottom wall 121a. The second peripheral wall 121c is cylindrical and extends along the axis L of the first peripheral wall 121b from the rear end of the first peripheral wall 121b. The inner diameter of the second peripheral wall 121c is larger than the inner diameter of the first peripheral wall 121b. The first annular wall 121d extends from the rear end of the second peripheral wall 121c toward the axis L of the second peripheral wall 121c. The first annular wall 121d is annular.

[0014] The input cylinder 122 has a third peripheral wall 122a and a second annular wall 122b. The third peripheral wall 122a is cylindrical. The third peripheral wall 122a is joined to the first annular wall 121d so that the axis L coincides with the second peripheral wall 121c of the main cylinder 121. The second annular wall 122b is cylindrical and extends from the rear end of the third peripheral wall 122a toward the axis L of the third peripheral wall 122a.

[0015] The master piston 123 is accommodated in the master cylinder 12 in a state of surface contact with the inner peripheral surfaces of the first peripheral wall 121b, the second peripheral wall 121c, and the first annular wall 121d of the main cylinder 121. The rear end portion of the master piston 123 protrudes rearward from the first annular wall 121d and is located within the input cylinder 122. When the master piston 123 is arranged in this way a master chamber Ra, a first liquid chamber Rb, and a servo chamber Rc are formed in the main cylinder 121. The master chamber Ra is a liquid chamber partitioned by the bottom wall 121a, the first peripheral wall 121b, and the master piston 123 at a position closer to the front end of the master cylinder 12. The master chamber Ra is connected to the master reservoir 11. Specifically, it is connected to the master reservoir 11 through a port formed at a location closer to the rear end of the master chamber Ra in the first peripheral wall 121b. The first liquid chamber Rb is a liquid chamber partitioned by the second peripheral wall 121c and the master piston 123 behind the master chamber Ra. The servo chamber Rc is a liquid chamber partitioned by the second peripheral wall 121c, the first annular wall 121d, and the master piston 123 behind the first liquid chamber Rb. Also, the pressure receiving area of the servo chamber Rc is set to be equal to the pressure receiving area of the master chamber Ra. The master chamber Ra and the first liquid chamber Rb are not connected to each other, that is, they do not exchange braking fluid. Also, the first liquid chamber Rb and the servo chamber Rc are not connected to each other.

[0016] The master piston 123 is movable with respect to the main cylinder 121 and the input cylinder 122. When moving, the master piston 123 slides on the inner peripheral surfaces of the first peripheral wall 121b, the second peripheral wall 121c, and the first annular wall 121d. Also, when the master piston 123 moves forward from the initial position shown in FIG. 1, the master chamber Ra and the master reservoir 11 are blocked by the master piston 123. As a result, as the master piston 123 moves forward, the hydraulic pressure in the master chamber Ra increases.

[0017] The input piston 124 is housed in the master cylinder 12, in surface contact with the inner surface of the third circumferential wall 122a and the inner surface of the second annular wall 122b of the input cylinder 122. The rear end of the input piston 124 protrudes rearward from the second annular wall 122b and is connected to the brake pedal 124a. The front end of the input piston 124 is spaced apart from the rear end of the master piston 123. This arrangement of the input piston 124 forms a second fluid chamber Rd and a third fluid chamber Re within the input cylinder 122. The second fluid chamber Rd is a fluid chamber partitioned by the first annular wall 121d of the main cylinder 121, the master piston 123, the third circumferential wall 122a, and the input piston 124. The third fluid chamber Re is a fluid chamber located rearward from the second fluid chamber Rd, partitioned by the third circumferential wall 122a, the second annular wall 122b, and the input piston 124. The third liquid chamber Re is connected to the master reservoir 11. The second liquid chamber Rd and the third liquid chamber Re are not connected to each other.

[0018] The input piston 124 is movable relative to the input cylinder 122. Therefore, when the brake pedal 124a is operated, i.e., pressed, the input piston 124 moves forward, i.e., toward the master piston 123, in proportion to the amount of operation. At this time, the input piston 124 slides against the inner surface of the third circumferential wall 122a and the inner surface of the second annular wall 122b. When the input piston 124 moves forward, brake fluid is supplied from the master reservoir 11 to the third fluid chamber Re. When the brake pedal 124a is released, the input piston 124 moves backward. At this time, brake fluid is discharged from the third fluid chamber Re to the master reservoir 11.

[0019] The master spring 125 is located within the main cylinder 121, specifically between the master chamber Ra, or more precisely, between the bottom wall 121a of the main cylinder 121 and the master piston 123. The master spring 125 biases the master piston 123 backward, that is, in a direction that expands the volume of the master chamber Ra. In other words, the master spring 125 is elastically compressed when the master piston 123 moves forward. When the force moving the master piston 123 decreases, the master spring 125 pushes the master piston 123 back.

[0020] The input spring 126 is located within the input cylinder 122, specifically between the second fluid chamber Rd of the input cylinder 122, more precisely, between the first annular wall 121d of the main cylinder 121 and the input piston 124. The input spring 126 is positioned as follows: The input piston 124 biases the input piston 124 backward, i.e., in a direction that increases the volume of the second liquid chamber Rd. In other words, the input spring 126 is elastically compressed when the input piston 124 moves forward. When the force moving the input piston 124 decreases, the input spring 126 pushes the input piston 124 back.

[0021] (liquid path) The fluid passage 14A connects the master chamber Ra of the master cylinder 12 to the front wheel cylinder 17A via the adjustment unit 1B. The fluid passage 14B connects the first fluid chamber Rb to the second fluid chamber Rd. The fluid passage 14C connects the master reservoir 11 to the fluid passage 14B. The fluid passage 14D connects the servo chamber Rc of the master cylinder 12 to the rear wheel cylinder 17B via the adjustment unit 1B.

[0022] (First shut-off valve and second shut-off valve) The first on-off valve 15A is located in the fluid passage 14B on the side of the second fluid chamber Rd beyond the connection point with the fluid passage 14C. The second on-off valve 15B is located in the fluid passage 14C between the connection point with the fluid passage 14B and the connection point with the electric cylinder 16. Both the first on-off valve 15A and the second on-off valve 15B are normally closed solenoid valves. During braking, current is supplied to the first on-off valve 15A and the second on-off valve 15B, respectively. At this time, the first on-off valve 15A opens, and the first fluid chamber Rb and the second fluid chamber Rd are connected to the stroke simulator 13. At the same time, the second on-off valve closes, and the first fluid chamber Rb and the second fluid chamber Rd are isolated from the master reservoir 11. The stroke simulator 13 then generates a reaction force corresponding to the amount of operation of the brake pedal 114a.

[0023] (Electric cylinder) The electric cylinder 16 is a pressurizing source that supplies brake fluid to the master cylinder 12 and the adjustment unit 1B. The electric cylinder 16 is connected to the rear wheel cylinder 17B and the servo chamber Rc of the master cylinder 12. That is, the electric cylinder 16 can supply brake fluid to the rear wheel cylinder 17B and the servo chamber Rc. The electric cylinder 16 discharges brake fluid pressurized to an output pressure Pc (first hydraulic pressure) corresponding to the amount of operation of the brake pedal 124a (hereinafter referred to as the operating displacement amount Ss) from the output port 16a to the fluid passage 14D. Specifically, a control device (not shown) calculates a target pressure Pt based on the operating displacement amount Ss. The control device then controls the electric motor 163 of the electric cylinder 16 so that the output pressure Pc matches the target pressure Pt. The output pressure Pc is detected by the output pressure sensor Sc. Here, the output pressure sensor Sc is a hydraulic pressure sensor that measures the output pressure Pc. Furthermore, the amount of operating displacement Ss can be measured, for example, by a stroke sensor SS provided on the brake pedal 124a.

[0024] The brake fluid with hydraulic pressure Pc output from the electric cylinder 16 is supplied to the servo chamber Rc and the adjustment unit 1B via the fluid passage 14D. When brake fluid is supplied to the servo chamber Rc, the master piston 123 moves forward, i.e., in the direction that decreases the volume of the master chamber Ra, and generates the master pressure Pm. In other words, as the master piston 123 moves, pressurized brake fluid with hydraulic pressure Pm is discharged from the master chamber Ra into the fluid passage 14A. The brake fluid with hydraulic pressure Pm (=Pc) discharged into the fluid passage 14A is supplied to the front wheel cylinder 17A via the adjustment unit 1B. In other words, the front wheel cylinder 17A can be said to be connected to the electric cylinder 16 (pressure source) via the master cylinder 12. As described above, in this embodiment, the pressure-receiving area of ​​the master chamber Ra of the master cylinder 12 is set to be equal to the pressure-receiving area of ​​the servo chamber Rc. Therefore, the output pressure Pc is equal to the master pressure Pm.

[0025] The electric cylinder 16 (pressure source) has been described above, but the configuration of the pressure source in the pressurizing unit 1A according to this embodiment is not particularly limited. That is, the pressurizing unit 1A is equipped with an accumulator type pressure source (see Japanese Patent Publication No. 2013-107561, etc.) Alternatively, a recirculating pressure source (see Japanese Patent Publication No. 2019-059294, etc.) may be provided. This is because the braking mechanism 1 according to this embodiment measures the wheel pressure Pw using a wheel pressure sensor Sw.

[0026] (Wheel cylinder) When brake fluid is supplied, wheel cylinders 17A and 17B move brake pads (not shown). The moved brake pads are pressed against a rotating plate (not shown) that rotates integrally with the wheels FL, FR, RL, and RR. This applies a braking force to the wheels FL, FR, RL, and RR. The higher the wheel pressure Pw (second hydraulic pressure), which is the hydraulic pressure inside the wheel cylinders 17A and 17B, the stronger the brake pads are pressed against the rotating plate. In other words, the higher the wheel pressure Pw, the greater the braking force generated by the wheels FL, FR, RL, and RR.

[0027] [Adjustment Unit] As shown in Figure 2, the adjustment unit 1B is for performing anti-skid control to stabilize vehicle behavior. The adjustment unit 1B individually adjusts the wheel pressure Pw of each wheel cylinder 17A and 17B to individually adjust the braking force of the wheels FL, FR, RL, and RR. The adjustment unit 1B includes a front wheel hydraulic pressure adjustment section 18A and a rear wheel hydraulic pressure adjustment section 18B. The front wheel hydraulic pressure adjustment section 18A and the rear wheel hydraulic pressure adjustment section 18B are independent of each other in the hydraulic circuit. Therefore, the adjustment unit 1B can independently adjust the wheel pressure acting on the front wheel cylinder 17A and the wheel pressure acting on the rear wheel cylinder 17B. Hereinafter, the adjustment unit 1B will be described with the pressurizing unit 1A side as upstream and the wheel cylinders 17A and 17B side as downstream. Furthermore, since the front wheel hydraulic pressure adjustment unit 18A and the rear wheel hydraulic pressure adjustment unit 18B share many common components, we will first explain the components of the front wheel hydraulic pressure adjustment unit 18A, and then explain only the differences between the rear wheel hydraulic pressure adjustment unit 18B and the front wheel hydraulic pressure adjustment unit 18A.

[0028] (First hydraulic output section) The front wheel hydraulic pressure adjustment unit 18A is configured to pressurize the wheel pressure Pw of the front wheel cylinder 17A based on the master pressure Pm from the upstream side. Furthermore, the front wheel hydraulic pressure adjustment unit 18A is configured to regulate the wheel pressure Pw of the front wheel cylinder 17A. The front wheel hydraulic pressure adjustment unit 18A is located between the master cylinder 12 and the front wheel cylinder 17A of the pressurizing unit 1A.

[0029] Brake fluid is supplied to the front wheel hydraulic pressure adjustment unit 18A from the master cylinder 12 of the pressurizing unit 1A. The front wheel hydraulic pressure adjustment unit 18A is configured to increase the hydraulic pressure of the front wheel cylinder 17A based on the base hydraulic pressure generated by the pressurizing unit 1A. The front wheel hydraulic pressure adjustment unit 18A is configured to pressurize the front wheel cylinder 17A by generating a differential pressure between the input hydraulic pressure and the hydraulic pressure of the front wheel cylinder 17A.

[0030] The front wheel hydraulic pressure adjustment unit 18A includes a fluid passage 14A, a pressure boosting valve 181, a check valve 181a, a holding valve 182, a check valve 182a, a pressure reducing fluid passage 183a, a pressure reducing valve 183, a pump fluid passage 184a, a pump 184, an electric motor 185, a recirculation fluid passage 186a, a low-pressure reservoir 186, a master pressure sensor Sm, and a wheel pressure sensor Sw.

[0031] The fluid passage 14A is a fluid passage for brake fluid connecting the master cylinder 12 of the pressurizing unit 1A and the front wheel cylinder 17A. In this embodiment, the fluid passage 14A branches at branching section X into a right-side fluid passage 14A connected to the right front wheel cylinder 17A and a left-side fluid passage 14A connected to the left front wheel cylinder 17A. The configurations provided in each of the left and right fluid passages 14A are a holding valve 182, a check valve 182a, a pressure reducing fluid passage 183a, and a pressure reducing valve 183 The wheel pressure sensor Sw has the same configuration on both the left and right sides. Therefore, in the following description of the configurations provided in each of the left and right fluid passages 14A, only the configuration on the right side will be explained, and the configuration on the left side will be omitted.

[0032] The pressure boosting valve 181 is a normally open linear valve, or normally open linear solenoid valve, installed in the fluid passage 14A between the branch section X and the master pressure sensor Sm. By controlling the opening degree of the pressure boosting valve 181, a differential pressure can be generated between the upstream and downstream sides of the pressure boosting valve 181. In the rear wheel hydraulic pressure adjustment section 18B, the pressure boosting valve 181 is installed between the branch section X and the pressurizing unit 1A. This is because the rear wheel hydraulic pressure adjustment section 18B does not have a master pressure sensor Sm.

[0033] The check valve 181a is installed in parallel with the pressure boosting valve 181. The check valve 181a is configured to allow the flow of brake fluid only from the upstream side to the downstream side.

[0034] The retaining valve 182 is located in the fluid passage 14A of the brake fluid that connects the wheel cylinder 17A to the pressurizing source that pressurizes the wheel cylinder 17A. The retaining valve 182 is a normally open linear valve, or normally open linear solenoid valve, that can suppress the pressurization of the wheel cylinder 17A by the pressurizing source by receiving an electric current. In other words, the retaining valve 182 is located in the fluid passage 14A on the side of the wheel cylinder 17A that is connected to the position (branch X) where the brake fluid is supplied by the electric cylinder 16. When no current is supplied to the retaining valve 182, the retaining valve 182 is fully open. When current is supplied to the retaining valve 182, the amount of opening is reduced according to the value of the current. Therefore, a predetermined current is supplied in order to maintain a predetermined differential pressure.

[0035] Here, we will explain the difference between the pressure boosting valve 181 and the retaining valve 182 that has been described so far. When the electric motor 185 is driven, the pump 184 draws bremsert fluid from the upstream side of the pressure boosting valve 181 and discharges it to the downstream side (branch section X) of the pressure boosting valve 181. This generates a circulating flow of bremsert fluid through the pressure boosting valve 181. The thrust of the solenoid 181b of the pressure boosting valve 181 acts to counteract the circulating flow, i.e., the flow of bremsert fluid from branch section X toward the upstream side, as shown in Figure 3. When the gap between the valve seat 181c and the valve body 181d is narrowed by this thrust, the regulated pressure Pp, which is the fluid pressure in the fluid passage 14A between the pressure boosting valve 181 and the retaining valve 182, becomes greater than the master pressure Pm due to the orifice effect. Note that no current is supplied to the pressure boosting valve 181 when the operating characteristics of the retaining valve 182 are acquired by the characteristic acquisition device 2, which will be described later. Therefore, the pressure boosting valve 181 is fully open at this time.

[0036] On the other hand, the thrust of the solenoid 182b of the retaining valve 182 acts to counteract the flow of brake fluid from the branch X to the front wheel cylinder 17A. When this thrust narrows the gap between the valve seat 182c and the valve body 182d, the retaining valve 182 can prevent the regulating pressure Pp from being transmitted to the front wheel cylinder 17A. If an increase in wheel pressure Pw is required, the retaining valve 182 opens, and the fluid pressure acting on the wheel cylinder 17A becomes equal to the regulating pressure Pp.

[0037] As described above, by setting the pressure-receiving area of ​​the master chamber Ra and the pressure-receiving area of ​​the servo chamber Rc to be equal, the output pressure Pc is equal to the master pressure Pm. Furthermore, when the operating characteristics of the retaining valve 182 are acquired by the characteristic acquisition device 2 described later, the pressure boosting valve 181 is fully open. Therefore, the master pressure Pm at this time is equal to the adjustment pressure Pp. Consequently, the output pressure Pc, master pressure Pm, and adjustment pressure Pp are all equal when the operating characteristics are acquired. In other words, a hydraulic pressure equal to the output pressure Pc acts on the retaining valve 182 when the operating characteristics are acquired.

[0038] As shown in Figure 2, the check valve 182a is installed in parallel with the retaining valve 182. The check valve 182a is configured to allow the flow of brake fluid only from the downstream side to the upstream side.

[0039] The pressure reducing fluid passage 183a is a fluid passage in fluid passage 14A that connects the space between the retaining valve 182 and the wheel cylinder 17A to the low-pressure reservoir 186. A pressure reducing valve 183 is provided on the pressure reducing fluid passage 183a. The pressure reducing valve 183 is a normally closed solenoid valve provided on the pressure reducing fluid passage 183a. When the pressure reducing valve 183 is open, the brake fluid in the wheel cylinder 17A can flow into the low-pressure reservoir 186 via the pressure reducing fluid passage 183a. Therefore, by opening the pressure reducing valve 183, the pressure in the wheel cylinder 17A can be reduced.

[0040] The pump fluid passage 184a is a fluid passage that connects the space between the pressure reducing valve 183 and the low-pressure reservoir 186 in the pressure reducing fluid passage 183a to the branch X of the fluid passage 14A. A pump 184 is provided in the pump fluid passage 184a.

[0041] Pump 184 is a pump that operates in response to the drive of an electric motor 185, and is, for example, a well-known piston pump or gear pump. The suction side of pump 184 is connected to a low-pressure reservoir 186, and the discharge side of pump 184 is connected to a branching section X. When pump 184 operates, it draws in brake fluid from the low-pressure reservoir 186 and supplies brake fluid to the branching section X. For example, if each retaining valve 182 is closed and the brake fluid in the low-pressure reservoir 186 is to be pumped up by driving pump 184, the brake fluid discharged by pump 184 is supplied to the master cylinder 12 of the pressurizing unit 1A via the branching section X. In the case of the rear wheel hydraulic pressure adjustment section 18B, the brake fluid discharged by pump 184 is supplied to the electric cylinder 16 of the pressurizing unit 1A via the branching section X.

[0042] The low-pressure reservoir 186 is a well-known pressure-regulating reservoir that stores breech fluid and is connected to the depressurizing fluid passage 183a and the recirculating fluid passage 186a. The recirculating fluid passage 186a is a fluid passage that connects the fluid passage 14A upstream of the pressure boosting valve 181 to the low-pressure reservoir 186. The breech fluid in the low-pressure reservoir 186 is drawn in by the operation of the pump 184. When the amount of breech fluid in the low-pressure reservoir 186 decreases, the valve in the low-pressure reservoir 186 opens, and breech fluid is supplied from the fluid passage 14A to the low-pressure reservoir 186 via the recirculating fluid passage 186a.

[0043] The master pressure sensor Sm is a hydraulic pressure sensor that measures the master pressure Pm. The master pressure Pm is the hydraulic pressure of the brake fluid in the first fluid passage 14a and is a type of first hydraulic pressure. The first fluid passage 14a constitutes part of the fluid passage 14A and connects the electric cylinder 16 (pressure source) and the retaining valve 182 of the pressurizing unit 1A via the master cylinder 12. The master pressure sensor Sm is located in the fluid passage 14A on the pressurizing unit 1A side of the pressure boosting valve 181. The master pressure Pm data measured by the master pressure sensor Sm is output to the characteristic acquisition device 2. In the rear wheel hydraulic pressure adjustment section 18B, the first fluid passage 14a directly connects the electric cylinder 16 and the retaining valve 182.

[0044] The wheel pressure sensor Sw is a hydraulic pressure sensor that measures the second hydraulic pressure as the wheel pressure Pw. The second hydraulic pressure is the hydraulic pressure of the brake fluid in the second hydraulic passage 14b. The second hydraulic passage 14b constitutes part of the hydraulic passage 14A and connects the retaining valve 182 and the front wheel cylinder 17A. The wheel pressure sensor Sw is located in the hydraulic passage 14A on the side of the retaining valve 182 that is on the front wheel cylinder 17A side. The wheel pressure data Pw measured by the wheel pressure sensor Sw is output to the characteristic acquisition device 2. In this embodiment, the wheel pressure sensor Sw is placed in each hydraulic passage 14A (two in total, or four in total if combined with the rear wheel described later). Therefore, the adjustment unit 1B in this embodiment can measure the four wheel pressures Pw simultaneously and output them to the characteristic acquisition device 2 at once.

[0045] (Second hydraulic output section) The rear wheel hydraulic pressure adjustment unit 18B, like the front wheel hydraulic pressure adjustment unit 18A, is configured to pressurize the wheel pressure Pw of the rear wheel cylinder 17B based on the output pressure Pc from the upstream side using a pressure boosting valve 181, etc. Furthermore, the rear wheel hydraulic pressure adjustment unit 18B is configured to regulate the pressure of the wheel cylinder 17B using a holding valve 182, etc. The rear wheel hydraulic pressure adjustment unit 18B is located between the electric cylinder 16 and the rear wheel cylinder 17B. The rear wheel hydraulic pressure adjustment unit 18B is configured similarly to the front wheel hydraulic pressure adjustment unit 18A, except that it does not have a master pressure sensor Sm.

[0046] [Characteristics acquisition device] Next, the characteristic acquisition device 2 will be described. The characteristic acquisition device 2 calculates the operating characteristics of the retaining valve 182 of the adjustment unit 1B. The "operating characteristics (IP characteristics)" refer to the relationship between the current Ia supplied to the retaining valve 182 and the differential pressure ΔP generated by the retaining valve 182. Note that there are individual differences in these operating characteristics for each retaining valve 182.

[0047] {Configuration of the characteristic acquisition device} As shown in Figure 4, the characteristic acquisition device 2 comprises an input unit 21, a storage unit 22, an output unit 23, and a control unit 24.

[0048] [Input section] The input section 21 receives the output pressure Pc, master pressure Pm, and wheel pressure Pw. The input section 21 also receives the value of the current supplied to the retaining valve 182, etc. The braking mechanism 1 (i.e., the pressurizing unit 1A, adjustment unit 1B, and drive circuit 1C) is equipped with a current sensor Si, an output pressure sensor Sc, a master pressure sensor Sm, and a wheel pressure sensor Sw. Therefore, the input section 21 consists of terminals to which the current sensor Si, output pressure sensor Sc, and wheel pressure sensor Sw are connected.

[0049] [Output section] The output unit 23 outputs the calculation result from the control unit 24.

[0050] [Storage section] The memory unit 22 stores various types of data. These types of data include, for example, sensor measurement data and calculation results from the control unit 24. However, if the memory unit 22 does not need to store various types of data, for example, if the data is stored in the control unit 24 or in the vehicle's memory, the characteristic acquisition device 2 does not need to have a memory unit 22.

[0051] [Control Unit] The control unit 24 includes a pressure control unit 241, a power supply control unit 242, a current acquisition unit 243, a first acquisition unit 244, a second acquisition unit 245, a calculation unit 246, and an output control unit 247.

[0052] (Pressurization control unit) The pressurization control unit 241 controls the electric cylinder 16 (pressurization source) of the pressurization unit 1A. The specific control of the electric cylinder 16 will be described later.

[0053] (Power supply control unit) The power supply control unit 242 controls the supply of current to the holding valve 182. Specific details of the power supply control will be described later.

[0054] (Current acquisition part) The current acquisition unit 243 acquires the value Ia of the current supplied to the holding valve 182 at any arbitrary timing. The current acquisition unit 243 acquires the measurement value of the current sensor Si as the current value Ia. The current sensor Si is provided in the drive circuit 1C, or between the drive circuit 1C and the holding valve 182. The current acquisition unit 243 also stores the acquired current value in the storage unit 22.

[0055] (1st acquisition part) The first acquisition unit 244 acquires the output pressure Pc, that is, the first liquid pressure in the first liquid passage 14a. The first acquisition unit 244 acquires the output pressure Pc via the input unit 21 each time the current acquisition unit 243 acquires the value of the current. More specifically, the first acquisition unit 244 acquires the output pressure Pc at the same time that the current acquisition unit 243 acquires the value of the current. The timing at which the first acquisition unit 244 acquires the output pressure Pc may be slightly different from the timing at which the current acquisition unit 243 acquires the value of the current.

[0056] (Second acquisition part) The second acquisition unit 245 acquires the wheel pressure Pw, that is, the second hydraulic pressure in the second fluid passage 14b. The second acquisition unit 245 acquires the wheel pressure Pw via the input unit 21 each time the current acquisition unit 243 acquires the value of the current. More specifically, the second acquisition unit 245 acquires the wheel pressure Pw at the same time that the current acquisition unit 243 acquires the value of the current. Note that the timing at which the second acquisition unit 245 acquires the wheel pressure Pw may be slightly different from the timing at which the current acquisition unit 243 acquires the value of the current.

[0057] (Calculation section) The calculation unit 246 calculates the operating characteristics based on the value of the current supplied to the holding valve 182 and the hydraulic pressure difference between the output pressure Pc obtained by the first acquisition unit 244 and the wheel pressure Pw obtained by the second acquisition unit 245. The calculation unit 246 stores the calculated results (hydraulic pressure difference, operating characteristics, etc.) in the storage unit 22. The specific method for calculating the operating characteristics will be described later.

[0058] (Output control unit) The output control unit 247 outputs the calculation results (operating characteristics, etc.) from the calculation unit 246 to the output unit 23.

[0059] {Procedure for acquiring characteristics} The characteristic acquisition device 2 acquires the operating characteristics of the retaining valve 182 as follows.

[0060] When the operating start conditions for the characteristic acquisition device 2 connected to the braking mechanism 1 are met (for example, when a predetermined acquisition start operation is performed on the characteristic acquisition device 2, or when a predetermined time has elapsed since connection to the braking mechanism 1), as shown in Figure 5(b), the power supply control unit 242 first supplies a current of magnitude i0 to the retaining valve 182, thereby completely closing the retaining valve 182. As described above, the retaining valve 182 is a normally open linear valve. Therefore, by continuing to supply current, the retaining valve 182 gradually begins to close. The retaining valve 182 continues its closing operation thereafter and eventually closes completely.

[0061] After the retaining valve 182 is completely closed, the pressurizing control unit 241 controls the electric cylinder 16 so that the output pressure Pc remains constant at a predetermined value. Specifically, the pressurizing control unit 241 controls the electric cylinder 16 so that the output pressure Pc from the pressurizing unit 1A, which was initially 0 (atmospheric pressure), becomes a predetermined value p0 as shown in Figure 5(a) (t1~t2). After the output pressure Pc reaches the predetermined value p0, the pressurizing control unit 241 performs feedback control so that the output pressure Pc is maintained at the predetermined value p0 even if factors that cause fluctuations in the output pressure Pc act upon it. At this time, since the retaining valve 182 is completely closed, the wheel pressure Pw is initially It is the same as the output pressure, 0 (atmospheric pressure).

[0062] With the retaining valve 182 completely closed and the pressurization control unit 241 controlling the electric cylinder 16 so that the output pressure Pc remains constant at a predetermined value p0, the power supply control unit 242 gradually reduces the current supplied to the retaining valve 182 (t3~), as shown in Figure 5(b). The power supply control unit 242 gradually reduces the current from its previous magnitude i0 at a constant rate, that is, until it becomes 0, so that the relationship between time and the value of the current becomes linear. As the supplied current decreases, the thrust of the solenoid 182b (see Figure 3) decreases in the retaining valve 182. When the thrust of the solenoid 182b falls below the output pressure Pc, it can no longer resist the output pressure Pc and opens. As a result, the wheel pressure Pw begins to rise (t4) and eventually becomes equal to the output pressure Pc (t8).

[0063] While the power supply control unit 242 is reducing the current (t3~), the current acquisition unit 243 acquires the values ​​of the current supplied to the holding valve 182 i1, i2...in multiple times (t5, t6...t7). In this embodiment, the current acquisition unit 243 acquires the values ​​of the current i1, i2...in while the wheel pressure Pw is rising after the power supply control unit 242 has started to reduce the current. The period during which the current acquisition unit 243 acquires the values ​​of the current i1, i2...in may be constant or not.

[0064] Simultaneously with the current acquisition unit 243 acquiring current values ​​i1, i2, etc., the first acquisition unit 244 acquires the output pressure Pc at that time (t5, t6, etc., t7). As a result, multiple output pressures Pc corresponding to multiple current values ​​acquired by the current acquisition unit 243 are obtained. Also, simultaneously with the current acquisition unit 243 acquiring current values, the second acquisition unit 245 acquires the wheel pressure Pw at that time (t5, t6, etc., t7). As a result, multiple wheel pressures Pw corresponding to multiple current values ​​acquired by the current acquisition unit 243 are obtained.

[0065] Each time the first acquisition unit 244 and the second acquisition unit 245 acquire the output pressure Pc and wheel pressure Pw, after the data acquisition is complete, the calculation unit 246 calculates the hydraulic pressure differences Δp1, Δp2...Δpn. The hydraulic pressure differences Δp1, Δp2...Δpn are the differences between the output pressure Pc and wheel pressure Pw acquired at each timing. The calculation unit 246 then stores the calculated hydraulic pressure differences Δp1, Δp2...Δpn in the storage unit 22. In this embodiment, the calculation unit 246 calculates a function showing the relationship between current and hydraulic pressure difference as an operating characteristic, based on multiple current values ​​i1, i2...in obtained by the current acquisition unit 243 acquiring multiple times, and multiple hydraulic pressure differences Δp1, Δp2...Δpn. The "multiple hydraulic pressure differences" are the set of differences between the output pressure Pc acquired by the first acquisition unit 244 and the wheel pressure Pw acquired by the second acquisition unit 245 each time the current acquisition unit 243 acquires a current value. Specifically, the calculation unit 246 approximates the relationship between the obtained multiple current values ​​i1, i2··in and the multiple hydraulic pressure differences Δp1, Δp2··Δpn with a polynomial (e.g., a quadratic function). When this calculation is visualized, for example as shown in Figure 6, the relationship between the current values ​​i1, i2··in and the hydraulic pressure differences Δp1, Δp2··Δpn at each timing is plotted on a plane with the differential pressure ΔP on the horizontal axis and the current Ia on the vertical axis, and a gentle curve is drawn by smoothly connecting each point. Alternatively, the relationship between current and hydraulic pressure difference may be determined as a characteristic map. For example, in a characteristic map, the values ​​between each point are obtained by linear interpolation.

[0066] The first acquisition unit 244 acquired the output pressure Pc using the output pressure sensor Sc, but it may also acquire the measured value of the master pressure sensor Sm (master pressure Pm) as the output pressure Pc. Accordingly, the calculation unit 246 calculates the hydraulic pressure difference ΔP based on the detected value of at least one of the output pressure sensor Sc and the master pressure sensor Sm.

[0067] {Effects and Effects of the Characteristic Acquisition Device} According to the characteristic acquisition device 2 described above, the retaining valve 1 in the mechanism for adjusting the braking force The operating characteristics of the linear valve used as 82 can be obtained by pressurizing the wheel cylinder with the electric cylinder 16.

[0068] Furthermore, in this embodiment, the output pressure Pc of the pressurizing unit 1A is obtained from the output pressure sensor Sc, and the wheel pressure Pw acting on the multiple (four) wheel cylinders 17A and 17B is obtained from multiple wheel pressure sensors Sw, respectively, to calculate the operating characteristics. Therefore, the characteristic acquisition device 2 according to this embodiment can acquire the operating characteristics of multiple retaining valves 182 at once.

[0069] Furthermore, if, for example, the operating characteristics are to be acquired by reducing the amount of opening of the retaining valve 182 from an open state, that is, by increasing the current to the retaining valve 182 from "0", then each time the wheel pressure Pw is acquired, the wheel pressure Pw must be reduced for the next acquisition. However, according to the characteristic acquisition device 2 of this embodiment, the amount of opening of the retaining valve 182 is gradually increased from a state in which it is completely closed, so there is no need to reduce the wheel pressure Pw. For this reason, the operating characteristics can be efficiently calculated in a series of operations.

[0070] <Second Embodiment> Next, a second embodiment of the present invention will be described. For the sake of convenience of explanation, components having the same function as those described in the first embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0071] [Brake mechanism] First, we will explain the differences between the braking mechanism 1 according to this embodiment and the braking mechanism 1 according to the first embodiment.

[0072] The braking mechanism 1 according to the first embodiment described above was equipped with a wheel pressure sensor Sw. In contrast, the braking mechanism 1 according to this embodiment does not have a configuration equivalent to the wheel pressure sensor Sw.

[0073] Furthermore, the braking mechanism 1 according to the first embodiment did not have any particular limitations on the configuration of the pressure source. In contrast, the pressure source of the pressure unit 1A according to this embodiment is limited to an electric cylinder 16. That is, the electric cylinder 16 according to this embodiment includes a cylinder 161 and a piston 162, similar to the electric cylinder 16 according to the first embodiment shown in Figure 1. The piston 162 moves inside the cylinder by the drive of an electric motor 163. However, the electric cylinder does not need to be configured to transmit the output pressure Pc to the front wheel cylinder 17A via the master cylinder 12, as in the first embodiment. That is, the electric cylinder may be configured to directly supply the output pressure Pc to the front wheel cylinder 17A, as shown in, for example, Japanese Patent Application Publication No. 2022-052375.

[0074] [Characteristics acquisition device]

[0075] Differences in the configuration of the characteristic acquisition device. As shown in Figure 7, the characteristic acquisition device 2A according to this embodiment includes an input unit 21, a storage unit 22, and an output unit 23 similar to those of the characteristic acquisition device 2 according to the first embodiment, as well as a control unit 24A.

[0076] [Control Unit] The control unit 24A includes a pressure control unit 241, a power supply control unit 242, a current acquisition unit 243, a calculation unit 246, and an output control unit 247, similar to those of the characteristic acquisition device 2 according to the first embodiment, as well as a first acquisition unit 244A and a second acquisition unit 245A.

[0077] (1st acquisition part) The first acquisition unit 244A is configured to detect the measured value (master pressure Pm) of the master pressure sensor Sm located in the first liquid passage 14a as the output pressure Pc. The first acquisition unit 244A is also configured to detect the measured value (output pressure Pc) of the output pressure sensor Sc.

[0078] (Second acquisition part) The second acquisition unit 245A estimates the wheel pressure Pw based on the output pressure Pc and the displacement of the piston 162 relative to the cylinder 161. The specific method for estimating the wheel pressure Pw will be described later.

[0079] Differences in the process of acquiring characteristics. In the first embodiment described above, the characteristic acquisition device 2 calculated the operating characteristics using the wheel pressure Pw measured by the wheel pressure sensor Sw. In contrast, the characteristic acquisition device 2A according to this embodiment calculates the operating characteristics using the wheel pressure Pw estimated by the second acquisition unit 245A as follows. The method for calculating the operating characteristics is the same as in the first embodiment described above. The following describes how to estimate the wheel pressure Pw when the holding valve 182 is completely closed and the pressurization control unit 241 controls the electric cylinder 16 (pressurization source) so that the output pressure Pc is constant at a predetermined value p0. This estimation of the wheel pressure Pw is performed for each wheel cylinder 17A and 17B.

[0080] First, the second acquisition unit 245A calculates the total fluid consumption qa based on the displacement amount Sp of the piston 162. The total fluid consumption qa is the amount of brake fluid consumed by the wheel cylinders 17A, 17B, fluid passages 14A, 14D, etc. The displacement amount Sp of the piston 162 can be calculated, for example, based on the motor rotation angle measured by the rotation angle sensor Sk provided on the electric motor 163 of the electric cylinder 16. The total fluid consumption qa is also the amount of brake fluid discharged from the electric cylinder 16. The second acquisition unit 245A calculates the total fluid consumption qa by multiplying the pressure-receiving area of ​​the piston 162 by the displacement amount Sp of the piston 162.

[0081] After calculating the total fluid consumption qa, or in parallel with the calculation of the total fluid consumption qa, the second acquisition unit 245A calculates the first fluid consumption Qc based on the first fluid volume characteristic Zc and the output pressure Pc. The first fluid consumption Qc is the amount of brake fluid required to generate the output pressure Pc when all holding valves 182 are completely closed. In other words, the first fluid consumption Qc is the amount of brake fluid consumed by the electric cylinder 16, the master cylinder 12, and the first fluid passage 14a when generating the output pressure Pc. This first fluid consumption Qc is determined by the stiffness (spring constant) of the master cylinder 12, the electric cylinder 16, and the first fluid passage 14a. The first fluid volume characteristic Zc is the fluid consumption characteristic of the first fluid passage 14a, i.e., the relationship between the output pressure Pc and the first fluid consumption Qc, and when graphed, it draws a curve as shown in Figure 8. This first fluid volume characteristic Zc can be determined in advance by experiment. In this embodiment, the characteristic acquisition device 2A stores the first liquid volume characteristic Zc in the storage unit 22. The second acquisition unit 245A in this embodiment calculates the first liquid consumption q0 at that time by applying the value p0 of the output pressure Pc to the graph (for example, a mathematical formula) showing the first liquid volume characteristic Zc.

[0082] After calculating the total fluid consumption qa and the first fluid consumption q0, the second acquisition unit 245A calculates the second fluid consumption Qw. The second fluid consumption Qw is the amount of brake fluid consumed by the second fluid passage 14b. The second fluid consumption Qw is also the amount of brake fluid that contributes to the increase in wheel pressure Pw. The second fluid consumption Qw is the amount of brake fluid required to generate wheel pressure Pw, assuming that the retaining valve 182 is completely closed and the electric cylinder 16 is controlled so that the output pressure Pc remains constant at a predetermined value p0. In other words, the second fluid consumption Qw is the amount of brake fluid consumed by the retaining valve 182, wheel cylinders 17A and 17B, and the second fluid passage 14b when generating wheel pressure Pw. This second fluid consumption Qw is determined by the stiffness (spring constant) of the brake caliper, brake pads, and the second fluid passage 14b. The second acquisition unit 245A calculates the second liquid consumption amount Qw by subtracting the first liquid consumption amount q0 from the total liquid consumption amount qa.

[0083] After calculating the second fluid consumption, the second acquisition unit 245A estimates the wheel pressure Pw based on the second fluid consumption and the second fluid volume characteristic Zw. The second fluid volume characteristic Zw is the fluid consumption characteristic of each second fluid channel 14b, i.e., the relationship between the wheel pressure Pw and the second fluid consumption Qw, and when plotted on a graph, it forms a curve as shown in Figure 8. This second fluid volume characteristic Zw can be determined in advance by experiment. The characteristic acquisition device 2A according to this embodiment stores the second fluid volume characteristic Zw in the storage unit 22. The second acquisition unit 245A according to this embodiment calculates the fluid pressure px corresponding to the second fluid consumption Qw (value qa-q0) by referring to the second fluid volume characteristic Zw. This fluid pressure px is the estimated value of the wheel pressure Pw in the above situation (output pressure Pc=p0, current value Ia=ia). In the above situation, the differential pressure ΔP is the value obtained by subtracting this estimated value px from the measured value of the output pressure sensor Sc (output pressure Pc), or the measured value of the master pressure sensor Sm detected as output pressure Pc (master pressure Pm).

[0084] (modified version) In the characteristic acquisition device 2A according to the second embodiment described above, the wheel pressure Pw was estimated using the first fluid volume characteristic Zc and the second fluid volume characteristic Zw, which were obtained experimentally in advance. However, the characteristic acquisition device 2A may be configured to determine the first fluid volume characteristic Zc and the second fluid volume characteristic Zw based on the output pressure Pc and the displacement amount Sp of the piston 162 of the electric cylinder.

[0085] When determining the first liquid volume characteristic Zc, the modified characteristic acquisition device 2A first has the power supply control unit 242 supply a current of magnitude i0 to a plurality of holding valves 182 to completely close the holding valves 182. Next, while the holding valves 182 are completely closed, the electric cylinder is controlled to increase the output pressure Pc. At this time, the second acquisition unit 245A acquires the displacement amount Sp of the piston 162 of the electric cylinder. The displacement amount Sp may be acquired once or multiple times. The second acquisition unit 245A also converts the acquired displacement amount Sp into the first liquid consumption amount q0. Then, the second acquisition unit 245A determines the first liquid volume characteristic Zc from the relationship between the output pressure Pc and the first liquid consumption amount q0 when the displacement amount Sp was obtained. Specifically, for example, the relationship between the output pressure value pb and the first liquid consumption amount qc at that time is approximated by a polynomial (for example, a quadratic function). When visualizing the calculation when approximating with this polynomial, for example as shown in Figure 9, the relationship between the output pressure value pb and the first liquid consumption amount qc is plotted on a plane with the output pressure Pc on the horizontal axis and the liquid consumption amounts Qc and Qw on the vertical axes, and a gentle curve passing through the plotted points is drawn.

[0086] Furthermore, when determining the second liquid volume characteristic Zw, the characteristic acquisition device 2A according to the modified example first controls the electric cylinder with the holding valve 182 open to increase the output pressure Pc. At that time, the second acquisition unit 245A acquires the displacement amount Sp of the piston 162 of the electric cylinder. The displacement amount Sp may be acquired once or multiple times. The second acquisition unit 245A also converts the acquired displacement amount Sp into the total liquid consumption amount qa. Then, the second acquisition unit 245A determines the overall liquid volume characteristic Zz from the relationship between the output pressure Pc and the total liquid consumption amount qa when the displacement amount Sp was obtained. Specifically, for example, the relationship between the output pressure value pb and the total liquid consumption amount qa at that time is approximated by a polynomial (for example, a quadratic function). When visualizing the calculation when approximating with this polynomial, for example as shown in Figure 9, the relationship between output pressure Pc and total fluid consumption qa is plotted on a plane with output pressure Pc on the horizontal axis and fluid consumption Qc and Qw on the vertical axis, and a gentle curve passing through the plotted points is drawn.

[0087] Next, the second liquid volume characteristic Zw is determined based on the obtained overall liquid volume characteristic Zz and first liquid volume characteristic Zc. Specifically, the second acquisition unit 245A calculates the total liquid consumption qa at an arbitrary liquid pressure Pc by referring to the overall liquid volume characteristic Zz. The second acquisition unit 245A also calculates the first liquid volume characteristic The first fluid consumption amount q0 at the same fluid pressure Pc is calculated by referring to the characteristic Zc. Then, the second acquisition unit 245A subtracts the first fluid consumption amount q0 from the calculated total fluid consumption amount qa to determine the second fluid consumption amount at the same fluid pressure Pc. For example, as shown in Figure 9, the second fluid consumption amount qb (=qz-qc, also called the "fluid volume difference") at the same fluid pressure value pb is determined by subtracting the first fluid consumption amount q0 at the same fluid pressure value pb from the total fluid consumption amount qz at the same fluid pressure value pb. This calculation may be performed for only one fluid pressure Pc or for multiple fluid pressure values ​​pb. Furthermore, the second acquisition unit 245A obtains the second fluid volume characteristic Zw from the relationship between the fluid pressure Pc and the obtained second fluid consumption amount qb. Specifically, for example, the relationship between the fluid pressure Pc and the second fluid consumption amount qb is approximated by a polynomial (e.g., a quadratic function). This polynomial represents the second fluid volume characteristic Zw. The second fluid volume characteristic Zw is obtained for each of the holding valves 182.

[0088] {Effects and Effects of the Characteristic Acquisition Device} According to the characteristic acquisition device 2A described above, similar to the characteristic acquisition device 2 in the first embodiment, the operating characteristics of the linear valve used as the retaining valve 182 in the mechanism for adjusting the braking force can be acquired by pressurizing the wheel cylinders 17A and 17B with the electric cylinder 16.

[0089] Furthermore, by estimating the wheel pressure Pw using the second acquisition unit 245A, it becomes unnecessary to provide a hydraulic pressure sensor in the second fluid passage 14b for measuring the wheel pressure Pw. Therefore, the characteristic acquisition device 2A can be applied to hydraulic pressure control devices that do not have such a hydraulic pressure sensor.

[0090] <Embodiments and Others> The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Furthermore, embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of the present invention.

[0091] For example, in the first and second embodiments described above, the case of acquiring the operating characteristics of a retaining valve 182 provided in an adjustment unit 1B that performs anti-skid control was explained. However, the retaining valves whose operating characteristics are acquired by the present invention are not limited to those provided in a mechanism that performs anti-skid control. For example, retaining valves provided in any mechanism that adjusts braking force, such as an anti-lock brake control mechanism, can be targeted.

[0092] Furthermore, in the first embodiment described above, the wheel pressure Pw of all wheel cylinders 17A and 17B was measured by the wheel pressure sensor Sw, and in the second embodiment described above, all wheel pressure Pw was estimated by the second acquisition unit 245A. However, the wheel pressure Pw of some of the wheel cylinders among all wheel cylinders 17A and 17B may be measured by the wheel pressure sensor Sw, and the remaining wheel pressure Pw may be estimated.

[0093] Furthermore, the functions of the characteristic acquisition devices 2 and 2A (hereinafter referred to as "devices") can be realized by a program that causes the control units 24 and 24A to function as the devices, and by a program that causes the control units 24 and 24A to function as each control block of the devices (particularly each part included in the control units 24 and 24A). In this case, the devices have at least one control device (e.g., a processor) and at least one storage device (e.g., memory) as hardware for executing the program. By executing the program using this control device and storage device, each of the functions described in the above embodiments is realized.

[0094] Furthermore, some or all of the functions of each of the above control blocks can also be realized by logic circuits. For example, an integrated circuit in which logic circuits that function as each of the above control blocks are formed is also included in the scope of the present invention. In addition, for example, each of the above control blocks can be realized by a quantum computer. It is also possible to implement the functionality of a lock. [Explanation of symbols]

[0095] 1, 1A braking mechanism 1A Pressurization Unit 16 Electric cylinder (pressure source) 1B Adjustment Unit 182 Holding valve (linear valve) 2, 2A characteristic acquisition device 21 Input section 22 Memory section 23 Output section 24, 24A Control Unit 241 Pressurization Control Unit 242 Power supply control unit 243 Current acquisition section 244, 244A 1st acquisition part 245, 245A 2nd acquisition part 246 Calculation Section 247 Output Control Unit Si current sensor SK Rotation Angle Sensor Sm Master Pressure Sensor

Claims

1. A characteristic acquisition device for calculating the operating characteristics of a normally open linear valve, which is provided in a brake fluid passage connecting a wheel cylinder and a pressurizing source that pressurizes the wheel cylinder, and which can suppress pressurization of the wheel cylinder by the pressurizing source by receiving an electric current, A power supply control unit that controls the supply of current to the linear valve, A first acquisition unit that acquires a first liquid pressure in the first liquid passage, which constitutes a part of the liquid passage and connects the pressurizing source and the linear valve, A second acquisition unit that acquires the second hydraulic pressure in the second hydraulic passage, which constitutes a part of the aforementioned hydraulic passage and connects the linear valve and the wheel cylinder, A calculation unit calculates the operating characteristics based on the value of the current supplied to the linear valve and the hydraulic pressure difference between the first hydraulic pressure obtained by the first acquisition unit and the second hydraulic pressure obtained by the second acquisition unit. A characteristic acquisition device equipped with the following features.

2. The system includes a pressure control unit that controls the aforementioned pressure source, The power supply control unit is By supplying current to the linear valve, the linear valve is completely closed. The linear valve is completely closed and the pressure control unit is controlling the pressure source so that the first hydraulic pressure remains constant at a predetermined value. The current supplied to the linear valve is then reduced. The power supply control unit includes a current acquisition unit that acquires the value of the current multiple times while the current is decreasing. The first acquisition unit acquires the first hydraulic pressure each time the current acquisition unit acquires the value of the current, The second acquisition unit acquires the second hydraulic pressure each time the current acquisition unit acquires the value of the current, The calculation unit calculates the relationship between the current and the hydraulic pressure difference as the operating characteristic, based on a plurality of current values ​​obtained by the current acquisition unit acquiring the current multiple times, and a plurality of hydraulic pressure differences which are a set of differences between the first hydraulic pressure acquired by the first acquisition unit and the second hydraulic pressure acquired by the second acquisition unit each time the current acquisition unit acquires the current value. The characteristic acquisition apparatus according to claim 1.

3. The first acquisition unit is configured to detect the measurement value of the hydraulic pressure sensor located in the first liquid passage as the first hydraulic pressure. The pressurizing source comprises a cylinder and a piston that moves within the cylinder by the drive of an electric motor. The second acquisition unit estimates the second hydraulic pressure based on the first hydraulic pressure and the displacement of the piston relative to the cylinder. The characteristic acquisition apparatus according to claim 1 or 2.

4. The aforementioned second acquisition unit is, Based on the displacement of the piston, the total amount of liquid consumed, which is the amount of liquid consumed in the liquid passage, is calculated. Based on the liquid consumption characteristics of the first liquid channel and the first liquid pressure, the first liquid consumption amount is calculated. The second liquid pressure is estimated based on the second liquid consumption amount obtained by subtracting the first liquid consumption amount from the total liquid consumption amount, and the liquid consumption characteristics of the second liquid channel. The characteristic acquisition apparatus according to claim 3.

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