JP2022115193A - Hydraulic pressure control device - Google Patents

Abstract

To provide a hydraulic pressure control device which can stably reduce the pulsation of a desired frequency, and can suppress the size enlargement of the device.SOLUTION: A hydraulic control device 1 comprises: a fluid supply part 2 for discharging fluid from a discharge port 2a; a first liquid path 3 for connecting the discharge port 2a and a fluid supply object 9, and zoned by a first peripheral wall part 80; a dead-end second liquid path 4 branched from the first liquid path 3 so as to form a side-branch type damper; and a cylindrical or bottomed cylindrical sleeve member 5 arranged in the second liquid path 4 so that an external peripheral face 51 abuts on a second peripheral wall part 81 which defines the second liquid path 4, forming a sleeve liquid path 52 in which the fluid can circulate while communicating with the first liquid path 3 at a center portion, and constituted so that a Young's modulus becomes lower than that of the first peripheral wall part 80.SELECTED DRAWING: Figure 1

Description

The present invention relates to hydraulic control devices.

A hydraulic pressure control device for controlling the pressure of an object to which fluid is supplied is provided with a damper, for example, for suppressing pulsation of fluid discharged from an electric pump. Fluid pulsation generates noise, so it is required to reduce pulsation at a specific target frequency, especially in hydraulic circuits used in vehicles. A Helmholtz-type damper using a metal diaphragm is known as one example of a damper for a hydraulic control device used in a vehicle control device. Further, as another damper used in the hydraulic circuit, there is a side branch type damper as disclosed in Japanese Patent Application Laid-Open No. 2007-278517, for example. In the side branch type damper, the frequency at which the damping effect is obtained is determined by physical properties (Young's modulus) and shape (pipe diameter and length).

JP 2007-278517 A

Since the Helmholtz damper uses a metal diaphragm, the frequency targeted for pulsation reduction changes depending on the load pressure (fluid pressure received by the damper). This depends on the fluid consumption characteristics of the metal diaphragm (relationship between hydraulic pressure and fluid consumption). Therefore, in the Helmholtz damper, for example, when the load pressure increases, there is a possibility that the pulsation reduction effect corresponding to a specific frequency cannot be sufficiently exhibited. In other words, there is room for improvement regarding the stability of the pulsation reducing action against pressure fluctuations.

Therefore, the inventor has come up with the idea of adopting a side branch type damper as a damper for a hydraulic control device used in a vehicle. Due to the principle of the side branch type damper, the pulsating pressure generated at the branch point where the main fluid path and the branch fluid path diverge collides with the anti-phase pulsating pressure returning from the branch fluid path and is reduced.

However, simply applying a side branch type damper to a hydraulic control device makes it difficult to achieve the performance required for, for example, a vehicle. That is, the damper of a hydraulic control device suitable for a vehicle braking system must stably reduce pulsation at a specific frequency (especially in a low frequency band for vehicles) against hydraulic pressure fluctuations within the normal operating range, and It is required to be able to suppress the enlargement of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic control device capable of stably reducing pulsation of a desired frequency and suppressing an increase in the size of the device.

The liquid pressure control device of the present invention includes a fluid supply section that discharges fluid from a discharge port, a first liquid path that connects the discharge port and an object to be supplied with fluid, and is partitioned by a first peripheral wall portion, a side A second fluid path branched from the first fluid path to form a branch-type damper, and a second fluid path inside the second fluid path so that the outer peripheral surface is in contact with a second peripheral wall portion that partitions the second fluid path. A sleeve liquid passage in which the fluid can flow by communicating with the first liquid passage is formed in the central portion, and the Young's modulus is configured to be lower than that of the first peripheral wall portion. a tubular bottom sleeve member.

According to the present invention, the sleeve liquid path and the second liquid path or only the sleeve liquid path form a branch liquid path that exhibits a side branch type damper function. As a result, pulsation of a specific frequency can be stably reduced without using a metal diaphragm. The frequency to be reduced by the side branch damper is inversely proportional to the length of the liquid path. Therefore, for example, in order to reduce the pulsation of frequencies in the low frequency band, it is necessary to lengthen the second liquid passage.

However, according to the present invention, the sleeve member having a Young's modulus relatively lower than that of the first peripheral wall section defining the first liquid passage forms the sleeve liquid passage within the second liquid passage. The frequency at which the side branch type damper has a damping effect is proportional to the sound velocity of the fluid, and the sound velocity of the fluid is proportional to the Young's modulus of the fluid passage. Therefore, the sleeve member reduces the sound velocity of the fluid in the second fluid passage, thereby lowering the frequency to be reduced. As a result, the frequency to be reduced can be lowered without increasing the length of the second liquid path, that is, without increasing the size of the device. Thus, according to the present invention, it is possible to stably reduce the pulsation of a desired frequency and to suppress the enlargement of the device.

1 is a configuration diagram of a hydraulic control device 1 of a first embodiment; FIG. FIG. 2 is a configuration diagram (cross-sectional view) of the sleeve member of the first embodiment; FIG. 8 is a configuration diagram (cross-sectional view) of a sleeve member according to a second embodiment; FIG. 11 is a configuration diagram (cross-sectional view) of a sleeve member according to a third embodiment; FIG. 11 is a configuration diagram (cross-sectional view) of a sleeve member according to a fourth embodiment; FIG. 4 is a configuration diagram (cross-sectional view) of a modified form of the sleeve member of the present embodiment;

An embodiment of the present invention will be described below with reference to the drawings. In addition, in each of the following embodiments, the same reference numerals are given to the parts that are the same or equivalent to each other. The descriptions and drawings in each embodiment can also be referred to in other embodiments. Each figure used for explanation is a conceptual diagram.

<First Embodiment>
The hydraulic control device 1 of the first embodiment is applied to a vehicle braking device 100 as shown in FIG. 1, and is an actuator device that adjusts the hydraulic pressure of the wheel cylinder 9 (hereinafter referred to as "wheel pressure"). The hydraulic control device 1 includes an electric pump (corresponding to a "fluid supply section") 2, a first fluid passage 3, a second fluid passage 4, a sleeve member 5, a plurality of electromagnetic valves 6, and a brake ECU 7. and a housing 8.

The electric pump 2 is a fluid supply device that discharges fluid from a discharge port 2a. The electric pump 2 sucks the fluid from an inlet (not shown). The electric pump 2 includes an electric motor 21 driven by the control of the brake ECU 7 and a pump 22 (for example, a gear pump) operated by the driving force of the electric motor 21 .

The first fluid path 3 is a fluid path that connects the discharge port 2a of the electric pump 2 and the wheel cylinder (corresponding to the “fluid supply object”) 9 . The first liquid path 3 is partitioned by the first peripheral wall portion 80 . In this embodiment, the first liquid path 3 is formed inside a housing 8 made of a metal block. The first liquid path 3 is defined by a first peripheral wall portion 80 (inner wall) that is part of the housing 8 . In other words, a part of the housing 8 is the first liquid passage forming portion (the piping portion of the first liquid passage 3: the first peripheral wall portion 80), and the first liquid passage 3 is the space in which the fluid flows. Fluid discharged from the electric pump 2 is supplied to the wheel cylinder 9 via the first fluid path 3 and a fluid path (not shown) outside the housing 8 . The first liquid passage 3 is a portion of the liquid passage that connects the electric pump 2 and the wheel cylinder 9 and is formed in the housing 8 .

The second fluid path 4 is a fluid path branching from the first fluid path 3 to form a blind alley so as to form a side branch type damper. The second liquid passage 4 is formed so as to function as a branch liquid passage of the side branch type damper without the sleeve member 5 . The second liquid path 4 is formed inside the housing 8 . The second fluid path 4 is defined by a second peripheral wall portion 81 (inner wall) that is part of the housing 8 and an end portion (a plug 82 in this example) that closes the fluid path to form a dead end. The second liquid path 4 extends perpendicularly to the extending direction of the first liquid path 3 .

In the first embodiment, the second liquid path 4 includes a small path 41 connected to the first liquid path 3 and a large path 42 connected to the small path 41 and having a larger diameter (cross-sectional area) than the small path 41. and have. One axial end of the large path 42 is closed with a plug 82 . The plug 82 is a metal member and constitutes a dead end wall of the second fluid path 4 . The plug 82 is press-fitted and fixed to the housing 8, for example. For example, the existing fluid path used in the Helmholtz damper in the housing 8 can be used as the second fluid path 4 in the side branch damper. In this case, the large path 42 corresponds to a portion of the Helmholtz damper in which the metal diaphragm and orifice plate are accommodated.

As shown in FIG. 2, the sleeve member 5 is arranged in the second liquid passage 4 so that the outer peripheral surface 51 contacts the second peripheral wall portion 81 that partitions the second liquid passage 4, and the first liquid is provided in the central portion. It is a cylindrical or bottomed cylindrical member that communicates with the passage 3 to form a sleeve liquid passage 52 through which fluid can flow, and that has a Young's modulus lower than that of the first peripheral wall portion 80 . The sleeve member 5 of the first embodiment is formed in a cylindrical shape.

The sleeve member 5 is installed in the small path 41 . The outer peripheral surface 51 of the sleeve member 5 is in contact with the second peripheral wall portion 81 that defines the small path 41 . The sleeve member 5 is made of rubber. The sleeve member 5 can also be said to be a rubber piping member. The sleeve member 5 is fixed to the small path 41 by, for example, press fitting. The Young's modulus of the sleeve member 5 made of rubber is lower than the Young's modulus of the housing 8 (the first peripheral wall portion 80 and the second peripheral wall portion 81) made of metal.

The sleeve member 5 is arranged coaxially with the second liquid passage 4 . A sleeve liquid passage 52 extending along the small passage 41 is formed in the central portion of the sleeve member 5 . In this example, the sleeve fluid path 52 is formed parallel to the small path 41 . The fluid that has flowed from the first fluid path 3 into the second fluid path 4 reaches the large path 42 via the sleeve fluid path 52 having a diameter smaller than that of the small path 41 . Fluid reaching the large path 42 bounces off the plug 82 and returns to the first fluid path 3 via the sleeve fluid path 52 . As a result, the pulsation of a specific frequency is reduced at the branch point of the first liquid path 3 and the second liquid path 4, and the action of the side branch type damper is exhibited. It can be said that the entire second liquid passage 4 including the sleeve member 5 constitutes a side branch type damper.

Between the outer peripheral surface 51 of the sleeve member 5 and the second peripheral wall portion 81, an air chamber 53 is formed which is sealed against the second liquid path 4 and filled with air. The air chamber 53 is defined by a recess 54 (for example, a groove) formed in the outer peripheral surface 51 of the sleeve member 5 and the second peripheral wall portion 81 . Both ends of the sleeve member 5 in the axial direction can be said to be seal portions 55 that seal between the second liquid passage 4 and the air chamber 53 .

In the first embodiment, a plurality of recesses 54 are arranged in the axial direction on the outer peripheral surface 51 . Each recess 54 aligned in the axial direction may be, for example, one continuous annular groove, or may be a plurality of grooves arranged in an annular shape. In the inner peripheral surface of the sleeve member 5, the distance between the axial end (seal portion 55) and the axial center (the portion where the air chamber 53 is formed) is from the axial end to the axial center. It is formed in a tapered shape so that the diameter gradually decreases toward the . Thus, the axial end face of the sleeve member 5 and the step of the sleeve fluid path 52 may be tapered in consideration of the flowability of the fluid and the sealing performance of the air chamber 53 .

The air chamber 53 is formed so that the Young's modulus of the sleeve member 5 can be maintained with respect to fluid pressure fluctuations in the normal range (for example, 1 to 3 MPa) during brake operation. The air chamber 53 is formed so that the sleeve fluid passage 52 maintains a state in which the diameter can be expanded due to the physical properties of rubber even when the maximum pressure in the normal range of braking operation is applied.

The electromagnetic valve 6 is arranged in a fluid path inside the housing 8 and opens and closes under the control of the brake ECU 7 . Inside the housing 8, a hydraulic circuit including a plurality of fluid paths, an electromagnetic valve 6, a reservoir (not shown), and the like is formed.

Brake ECU7 is an electronic control unit provided with a processor and memory. The brake ECU 7 controls the electromagnetic valve 6 and the electric pump 2 according to the brake operation and the like, thereby controlling the wheel pressure and the braking force. The brake ECU 7 is fixed to the housing 8 via, for example, a fixed case (not shown). The hydraulic control device 1 constitutes, for example, an ABS actuator or an ESC actuator.

(Effect of the first embodiment)
According to the first embodiment, the second liquid path 4 and the sleeve liquid path 52 form a side branch type damper (branch liquid path). As a result, pulsation of a specific frequency can be stably reduced without using a metal diaphragm. The damping frequency of the side branch type damper is inversely proportional to the length of the liquid path (branch liquid path). Therefore, for example, in order to reduce the pulsation of frequencies in the low frequency band, it is necessary to lengthen the second liquid passage 4 .

However, according to the first embodiment, the sleeve member 5 having a relatively lower Young's modulus than the first peripheral wall portion 80 that defines the first liquid passage 3 forms the sleeve liquid passage 52 in the second liquid passage 4. is doing. The frequency to be reduced in the side branch type damper is proportional to the sound velocity of the fluid, and the sound velocity of the fluid is proportional to the Young's modulus of the liquid passage. Therefore, the sleeve member 5 reduces the sound velocity of the fluid in the second liquid passage 4, thereby lowering the frequency to be reduced. As a result, the frequency to be reduced can be lowered without increasing the length of the second liquid path 4, that is, without increasing the size of the device. The frequency to be reduced can be adjusted by the Young's modulus of the sleeve member 5 . As described above, according to the first embodiment, it is possible to stably reduce the pulsation of a desired frequency and to suppress the increase in size of the device.

Further, for example, by manufacturing the sleeve member 5 separately from the second fluid path 4, it becomes possible to retrofit the sleeve member 5 to the existing fluid path or damper chamber. As a result, a side branch type damper that satisfies the requirements can be formed in the existing housing 8 (hydraulic circuit) without design change.

In addition, since the air chamber 53 is formed by the sleeve member 5 and the second peripheral wall portion 81, the Young's modulus of the sleeve member 5 can be easily maintained. Air is a compressible fluid, and deformation of the sleeve member 5 that reduces the volume of the air chamber 53 is allowed. Even if a high load pressure is applied to the second liquid passage 4, the presence of the air chamber 53 allows the sleeve member 5 to not only compressively deform but also elastically deform in the radially expanding direction, thereby maintaining a low Young's modulus of the sleeve member 5. easier to be

For example, by forming the sleeve member 5 so that the Young's modulus is maintained with respect to hydraulic pressure fluctuations in the normal use range, the desired frequency reduction effect can be maintained with respect to brake operation in the normal use range. In other words, it is possible to stably suppress the generation of sound (sound of a frequency that bothers the occupant) during normal brake operation.

<Second embodiment>
The second embodiment differs from the first embodiment mainly in the position and shape of the sleeve member, and mainly the different points will be described below. The sleeve member 5A of the second embodiment is arranged in the large path 42 of the second fluid path 4, as shown in FIG. The sleeve member 5A is a bottomed cylindrical rubber member. Therefore, the end portion (plug 82 ) of the second liquid passage 4 is covered with the sleeve member 5 . That is, the sleeve member 5</b>A has a bottom portion 56 which is the end portion of the sleeve liquid passage 52 and which is arranged to face the end portion of the second liquid passage 4 .

The sleeve member 5A is formed so that the sleeve fluid path 52 has the same diameter as the small path 41 under atmospheric pressure. A concave portion 54 that partitions the air chamber 53 together with the second peripheral wall portion 81 is formed in the outer peripheral surface 51 of the sleeve member 5A. The recess 54 is, for example, an annular groove or a plurality of grooves arranged in the circumferential direction.

One axial end (left end in FIG. 3) of the sleeve member 5A abuts on the plug 82 . The plug 82 restricts the movement of the sleeve member 5A in one axial direction. That is, the plug 82 functions as a restricting portion that restricts the movement of the sleeve member 5A within the second liquid passage 4. As shown in FIG.

In the second embodiment, the sleeve member 5A is arranged along the entire axial direction of the large path 42 . In other words, the axial length of the sleeve member 5A is the same as the axial length of the large path 42 (from the connection position with the small path 41 to the plug 82) in the arranged state. The other axial end of the sleeve member 5 is in contact with the step formed by the second peripheral wall portion 81 . Thus, in the second embodiment, the plug 82 and the step of the housing 8 (the step between the small path 41 and the large path 42) restrict movement in one and the other axial direction. The housing 8 (second peripheral wall portion 81) can also be said to be a restricting portion. The step between the plug 82 and the housing 8 can also be said to be a positioning portion for positioning the sleeve member 5A within the second liquid passage 4 .

(Effect of Second Embodiment)
Also in the second embodiment, the same effect as in the first embodiment is exhibited. Further, since the plug 82 and the housing 8 form a restricting portion, the movement of the sleeve member 5A due to the flow of fluid is effectively suppressed. Moreover, since the existing plug 82 functions as a restricting portion, there is no need to form a restricting portion separately. In addition, since a concave portion 87 into which the sleeve member 5 is fitted is formed in the second liquid passage 4 by the restricting portions (82, 8) on both sides in the axial direction, the positioning of the sleeve member 5A is facilitated, and the post-installation work of the sleeve member 5A is facilitated. is also easier. For example, in the case of the configuration of FIG. 3, a desired side branch type damper is formed by press-fitting the plug 82 after press-fitting the sleeve member 5A into the volume chamber (large path 42) of the existing housing 8. can be done.

<Third embodiment>
The difference between the third embodiment and the second embodiment is mainly the configuration of the air chamber 53, and mainly the different points will be described below. As shown in FIG. 4, a plurality of air chambers 53 are formed inside the sleeve member 5B of the third embodiment. The sleeve member 5B is a rubber foam material. The air chamber 53 is formed by air bubbles positively formed in the rubber. The sleeve member 5B is formed in a cylindrical shape with a bottom as in the second embodiment. In addition, in FIG. 4, since there are many air chambers 53, some symbols are omitted.

(Effect of the third embodiment)
Also in the third embodiment, the same effect as in the second embodiment is exhibited. Further, since the air chamber 53 is formed inside the sleeve member 5, it is possible to easily form a seal between the second liquid passage 4 and the air chamber 53, thereby improving the degree of freedom in design. Further, since the air chamber 53 is formed inside only by using a foam material for the sleeve member 5, manufacturing is facilitated.

<Fourth Embodiment>
The fourth embodiment differs from the first embodiment mainly in the shape of the second liquid passage 4 and the position of the sleeve member, and the differences will be mainly described below. The second fluid path 4 includes an internal fluid path 44 formed within the housing 8 and an external fluid path 45 formed within a piping member 84 outside the housing 8, as shown in FIG. The inner diameter of the piping member 84 (the diameter of the external liquid passage 45) is larger than the diameter of the internal liquid passage 44. As shown in FIG. The piping member 84 is a metal piping, and is fixed to the surface 83 of the housing 8 by screwing or the like.

5 C of sleeve members of 4th Embodiment are arrange|positioned inside the piping member 84 (namely, inside the external liquid path 45). The sleeve member 5C is a bottomed cylindrical rubber member. The Young's modulus of the sleeve member 5C is smaller than the Young's modulus of the first peripheral wall portion 80, as in the above embodiment. That is, the Young's modulus of the sleeve member 5C is smaller than the Young's modulus of the housing 8 (the first peripheral wall portion 80 and the second peripheral wall portion 81). In addition, the Young's modulus of the sleeve member 5C is smaller than that of the piping member 84 (the second peripheral wall portion 81) that defines the external liquid passage 45. As shown in FIG.

A plurality of air chambers 53 are formed between the outer peripheral surface 51 of the sleeve member 5C and the piping member 84 (second peripheral wall portion 81), as in the first embodiment. The sleeve member 5C is arranged in the entire axial direction inside the piping member 84 . The interior of the piping member 84 is filled with the sleeve member 5 . The sleeve member 5C is formed so that the sleeve fluid path 52 has the same diameter as the internal fluid path 44 under atmospheric pressure. The sleeve fluid path 52 is connected to the internal fluid path 44 . In other words, the branch liquid passage acting as a side branch type damper is composed of the internal liquid passage 44 and the sleeve liquid passage 52 .

Thus, in the fourth embodiment, a portion of the second liquid passage 4 is formed by the housing 8, and the remaining portion 46 including the end of the second liquid passage 4 is formed by the piping member 84 fixed to the housing 8. It is

(Effect of the fourth embodiment)
Also in the fourth embodiment, the same effect as in the first embodiment is exhibited. Further, by preparing a piping member 84 (hereinafter also referred to as a "piping unit") having a sleeve member 5C, for example, a desired side branch type damper can be formed externally to the housing 8. FIG. This piping unit can be replaced on demand with respect to the housing 8 .

<Others>
The present invention is not limited to the first to fourth embodiments described above. For example, the material of the sleeve members 5-5C is not limited to rubber, and may be another elastic material. Also, the sleeve members 5 to 5C may be made of a plurality of materials. For example, as shown in FIG. 6, the sleeve member may be formed of two rubber members 501 and 502 having different Young's moduli. For example, the rubber member 501 having a relatively low Young's modulus may be arranged on the inside, and the rubber member 502 having a relatively high Young's modulus may be arranged on the outside (or vice versa). The Young's modulus of the entire sleeve member should be lower than the Young's modulus of the first peripheral wall portion 80 that defines the first liquid passage 3 . Also, the sleeve member may be configured by sandwiching a rubber piping member between metal or resin piping members having different diameters, for example. Thus, the sleeve member may be formed of multiple layers.

Further, the sleeve members 5 to 5C may be cylindrical or bottomed cylindrical. Also, the sleeve members 5 to 5C may be arranged in at least a part of the second liquid passage 4 in the axial direction. For example, when a sleeve member is arranged along the entire axial direction of the second liquid path 4 , the branch liquid path of the side branch type damper is composed only of the sleeve liquid path 52 .

Also, the sleeve members 5 to 5C do not have to have the air chamber 53 . In other words, the sleeve members 5 to 5C may be designed without the air chamber 53 so that they can maintain their own Young's modulus in the operating environment depending on the material and shape (thickness, etc.). Further, when the air chamber 53 is formed, the air chamber 53 may be formed between the outer peripheral surface 51 and the second peripheral wall portion 81 and at least one of the insides of the sleeve members 5 to 5C. For example, the sleeve members 5, 5C may be made of foam. In this case, the recess 54 may or may not be present.

Moreover, the second liquid path 4 is not limited to being linear, and may be curved or bent. Also, the angle formed by the first liquid path 3 and the second liquid path 4 may not be a right angle. Further, the hydraulic control device 1 can be applied to devices other than vehicle braking devices. That is, the object to be supplied with fluid is not limited to the wheel cylinder 9 . Further, the fluid supply unit that supplies fluid is not limited to the electric pump 2, and may be an electric cylinder, for example. Further, the restricting portion that restricts the movement of the sleeve member 5 is not limited to the plug 82, and may be, for example, a step formed in the housing 8 or a snap ring fitted to the housing 8 or the like.

Also, the end portion (wall) of the second liquid path 4 may not be the plug 82 or the piping member 84, and may be configured by the housing 8, for example. Moreover, the diameter of each liquid path may be the same or different. However, from the viewpoint of fluid flow, it is preferable that the pipe diameters change less (for example, be the same). A "liquid path" in the present disclosure can also be referred to as a pipe or conduit, and may be a fluid path within the housing 8 or a fluid path within a tubular piping member. Also, the first fluid path 3 can be called a main fluid path, and the second fluid path 4 can be said to be a branch path.

DESCRIPTION OF SYMBOLS 1... Liquid pressure control apparatus 2... Electric pump (fluid supply part) 2a... Discharge port 3... 1st fluid path 4... 2nd fluid path 5, 5A, 5B, 5C... Sleeve member 51... Outer periphery Surface 52 Sleeve liquid path 53 Air chamber 8 Housing 80 First peripheral wall portion 81 Second peripheral wall portion 82 Plug (restriction portion) 84 Piping member 9 Wheel cylinder (fluid supply object).

Claims (5)

a fluid supply unit that discharges fluid from a discharge port;
a first fluid path that connects the discharge port and an object to be supplied with fluid and is partitioned by a first peripheral wall;
a dead end second fluid path branched from the first fluid path to form a side branch damper;
A sleeve liquid passage is arranged in the second liquid passage so that the outer peripheral surface abuts on a second peripheral wall portion that defines the second liquid passage, and communicates with the first liquid passage at a central portion thereof so that fluid can flow therethrough. and a cylindrical or bottomed cylindrical sleeve member configured to have a Young's modulus lower than that of the first peripheral wall portion;
A hydraulic control device comprising: Between the outer peripheral surface of the sleeve member and the second peripheral wall portion and at least one of the interior of the sleeve member, an air chamber sealed against the second fluid path and filled with air is formed. 2. A hydraulic control device according to claim 1, wherein: The fluid supply unit is an electric pump,
The object to be supplied with fluid is a foil cylinder,
3. The hydraulic control device according to claim 2, wherein said air chamber is formed so as to maintain a Young's modulus of said sleeve member against fluctuations in hydraulic pressure in a normal range during braking operation. A part of the second liquid path is configured by a housing,
The remaining portion including the end of the second liquid path is composed of a piping member fixed to the housing,
The hydraulic control device according to any one of claims 1 to 3, wherein the sleeve member is arranged inside the piping member. The hydraulic control device according to any one of claims 1 to 4, further comprising a restricting portion that restricts movement of the sleeve member within the second fluid passage.

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