master cylinder

Abstract

Disclosed is a master cylinder. The master cylinder according to the present embodiment includes: a hydraulic module having a main hole formed in an axial direction inside; a first piston inserted into the main hole on one side and capable of displacement, the other side exposed to the outside of the hydraulic module and connected to a brake pedal; a mounting seat having a sub hole formed in an axial direction inside and configured to allow the first piston to be inserted therethrough and capable of displacement, and a connection port connecting the sub hole and a reservoir; a cover provided on a side portion of the first piston; and a gap flow path formed by a gap between the first piston and the cover to communicate a first hydraulic chamber divided by the first piston on the main hole and the connection port.

Description

TECHNICAL FIELD

[0001] The present invention relates to a master cylinder, and more particularly, to a master cylinder that achieves reliability of operation while reducing operation noise and vibration. BACKGROUND

[0002] A brake system for performing braking is installed in a vehicle, and various types of systems for obtaining more powerful and stable braking force have recently been proposed.

[0003] According to the existing brake system, when a driver steps on a brake pedal, a hydraulic pressure required for braking is supplied to a wheel cylinder using a mechanically connected brake booster, but recently, an electronic brake system is widely used, in which a driver's braking intention is received in the form of an electric signal from a pedal displacement sensor that senses displacement of the brake pedal when the driver steps on the brake pedal, and thus a hydraulic pressure required for braking is supplied to the wheel cylinder.

[0004] Such an electronic brake system includes a master cylinder connected to a brake pedal to generate a hydraulic pressure through a pedal force of the brake pedal, a pedal stroke sensor that senses displacement of the brake pedal, a hydraulic pressure supply device that activates a motor to generate a hydraulic pressure of a pressurized medium according to information sensed through the pedal stroke sensor, an oil pressure control unit that supplies a hydraulic pressure generated in the hydraulic pressure supply device to a wheel cylinder after adjusting the hydraulic pressure, and the like. SUMMARY

[0005] Technical Problem to be Solved

[0006] The present embodiment aims to provide a master cylinder that achieves reliability of operation and improved performance.

[0007] The present embodiment aims to provide a master cylinder that can rapidly release residual pressure of a pressurized medium in a hydraulic chamber.

[0008] The present embodiment aims to provide a master cylinder that can reduce noise and vibration generated when a piston is displaced.

[0009] The present embodiment aims to provide a master cylinder that can maintain a constant piston operation stroke.

[0010] The present embodiment aims to provide a master cylinder that can prevent leakage of a pressurized medium and inflow of impurities.

[0011] The present embodiment aims to provide a master cylinder that alleviates impact applied to component elements, thereby improving durability of a product.

[0012] The present embodiment aims to provide a master cylinder that can achieve product assemblability and miniaturization.

[0013] Means for Solving the Technical Problem

[0014] According to an aspect of the present application, a master cylinder can be provided, including: a hydraulic module having a master hole formed in an axial direction inside; a first piston inserted into the master hole on one side to be displaceable, and exposed to an outside of the hydraulic module on the other side to be connected to a brake pedal; a mounting seat having a sub-hole formed in an axial direction inside, and a connection port connecting the sub-hole and a reservoir; a cover provided at a side portion of the first piston; and a gap flow path formed by a gap between the first piston and the cover to communicate a first hydraulic chamber divided by the first piston on the master hole and the connection port.

[0015] The first piston can include a mounting portion recessed in an axial direction on one side surface, and the cover can include a main body inserted into the mounting portion, and a flange portion expanded in a radial direction from a side end portion of the main body.

[0016] The gap flow path can include a first slit recessed in an axial direction on an outer circumferential surface of the main body, and a second slit recessed in a radial direction on the other side surface of the flange portion facing the side end portion of the first piston, and connected to the first slit.

[0017] The first piston can further include a hollow portion extended from the mounting portion, a communication hole communicating the hollow portion and the connection port, and a step surface formed between the mounting portion and the hollow portion, facing the other side surface of the main body, and the gap flow path can further include a third slit recessed in the radial direction on the step surface and connected to the second slit.

[0018] The third slit can be formed in a plurality on the step surface, and the gap flow path can further include a fourth slit recessed in a rim direction on the step surface to connect the plurality of third slits to each other.

[0019] The master cylinder can further include a second piston inserted into an inside of the first piston on the master hole to be displaceable, and an elastic member provided between the first piston and the second piston to provide a pedal feel, and a side end portion of the elastic member inserted into and coupled to an inside of the main body.

[0020] The elastic member can include a coupling protrusion protruded from the other side surface, and the cover can further include a coupling hole through-formed in the main body to insert the coupling protrusion.

[0021] The input rod is connected to the first piston at one end and to the brake pedal at the other end. The support plate is fixed to the input rod. The cover is supported at one end by the mounting seat and at the other end by the support plate, and is capable of being extended and retracted. The support plate includes an exhaust hole formed in a manner of communicating the inside and outside of the cover. The exhaust hole is formed at an angle with respect to the axial direction.

[0022] The sub-hole can further include a first step portion formed in a stepped manner at one end portion. The sub-hole can further include a first bushing member inserted into the first step portion and guiding the reciprocal movement of the first piston.

[0023] The damper member can be provided such that at least a portion thereof enters the inside of the first step portion.

[0024] The main hole can include a first hole formed to allow the first piston to be displaced, and a second hole formed inside the first hole to allow at least a portion of the second piston to be displaced and having a diameter smaller than that of the first hole. The second hole can include a second step portion formed in a stepped manner at the other end portion facing the first hole. The second hole can further include a second bushing member inserted into the second step portion and guiding the reciprocal movement of the second piston.

[0025] The sub-hole can include a third step portion formed in a stepped manner at the other end portion. The sub-hole can further include a third bushing member inserted into the third step portion and guiding the reciprocal movement of the first piston.

[0026] The second bushing member can be formed in a ring shape and include an inside groove portion recessed in a circumferential direction at an inner circumferential surface.

[0027] The first piston can include a main stem portion extending in an axial direction and a hanging portion expanded in a radial direction at one end portion of the main stem portion. One side of the damper member is supported by the hanging portion, and the other side is capable of facing and contacting the first bushing member.

[0028] The damper member can include a plurality of outside groove portions recessed at at least any one of one side and the other side.

[0029] The mounting seat can include a mounting protrusion protruding in a direction along the edge of one end portion of the sub-hole. An outer circumferential surface of the mounting protrusion and an inner circumferential surface of the main hole face or contact each other.

[0030] The hydraulic module can further include an axial hole formed in an axial direction and a communication hole communicating the main hole and the axial hole, and the second piston can include a hooking stage protruded from an outer circumferential surface, and a first limiter provided on an inner circumferential surface of the main hole, the hooking stage being hooked to be supported, and having an opening part formed on one side, and the communication hole being positioned inside the opening part.

[0031] The main hole can further include a first limiting groove recessed in a circumferential direction on an inner circumferential surface, and at least a portion of the first limiter can be inserted and positioned in the first limiting groove.

[0032] The first limiting groove can include a separation preventing part protruded from an inner side of the opening part.

[0033] The hydraulic module can further include an input rod having one end connected to the first piston and the other end connected to the brake pedal, a support plate fixed to the input rod, a cover having one end supported by the mounting seat and the other end supported by the support plate and being capable of being extended and contracted, and a piston spring having one end supported by the mounting seat and the other end supported by the support plate to elastically support the input rod or the first piston, and a noise suppressing protrusion protruded from an inner circumferential surface of the cover toward an inner side to maintain contact with at least a portion of an outer circumferential surface of the piston spring.

[0034] The hydraulic module can further include a second limiter provided on an outer circumferential surface of the first piston at a position exposed to an outside of the mounting seat, and the second limiter can include a receiving part positioned inside and through which the first piston passes, and a mounting opening part formed on one side.

[0035] The outer circumferential surface of the first piston can be formed in a cylindrical shape, and the receiving part can include a first center, a first receiving part having a first radius from the first center, a second center, and a second receiving part having a second radius from the second center, and the second center can be formed further closer to the mounting opening part than the first center, and the second radius can be smaller than the first radius.

[0036] Inventive Effects

[0037] According to the master cylinder of the embodiment, a residual pressure of a pressurizing medium in a hydraulic chamber can be rapidly released, and thus, reliability and performance of work can be improved.

[0038] According to the master cylinder of the embodiment, noise and vibration generated when a piston is displaced can be reduced.

[0039] According to the master cylinder of the embodiment, a constant working stroke of the piston can be maintained.

[0040] According to the master cylinder of the present embodiment, leakage of the pressurizing medium and inflow of impurities can be prevented.

[0041] According to the master cylinder of the present embodiment, an impact applied to the component elements can be mitigated, thereby improving the durability of the product.

[0042] According to the master cylinder of the present embodiment, the assembly and miniaturization of the product can be achieved.

[0043] Mark Description

[0044] 1: Master cylinder 100: Gap flow path

[0045] 101: First slit 102: Second slit

[0046] 103: Third slit 103: Third slit

[0047] 110: Hydraulic module 111: First hole

[0048] 112: Second hole 116: First seal

[0049] 117: Second seal 118: Shaft hole

[0050] 119: Hydraulic flow path 121: First piston

[0051] 123: Elastic member 124: Second piston

[0052] 127: Cover 140: Mounting seat

[0053] 142: Sub-hole 144: Noise suppression protrusion

[0054] 145: Connection flow path 146: Cover

[0055] 147: Support plate 147a: Exhaust hole

[0056] 148: Piston spring 151: First bushing member

[0057] 152: Shock absorber member 160: Second bushing member

[0058] 170: Third bushing member 182: First limiter

[0059] 190: Second limiter BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 is a perspective view showing a master cylinder according to the present embodiment.

[0061] Figure 2 is a cross-sectional view showing a master cylinder according to the present embodiment.

[0062] Figure 3 is a cutaway perspective view showing the master cylinder according to the present embodiment.

[0063] Figure 4 is a cutaway perspective view showing the first piston according to the present embodiment.

[0064] Figure 5 is a perspective view showing the cap according to the present embodiment.

[0065] Figure 6 is a cutaway perspective view showing the first piston according to the present embodiment.

[0066] Figure 7 is a view showing a portion A of Figure 2 enlarged.

[0067] Figure 8 is a view showing a portion B of Figure 2 enlarged.

[0068] Figure 9 is a view showing a portion E of Figure 8 enlarged, and is a sectional view of the first seal according to the present embodiment.

[0069] Figure 10 is a view showing a state in which the first seal according to the present embodiment is deformed due to the hydraulic pressure of the pressurizing medium.

[0070] Figure 11 is a split perspective view showing the second seal according to the present embodiment.

[0071] Figure 12 is a view showing a portion F of Figure 8 enlarged, and is a sectional view of the second seal according to the present embodiment.

[0072] Figure 13 and Figure 14 are views showing a portion A of Figure 2 enlarged, and show a state in which the first piston according to the present embodiment advances and returns, respectively.

[0073] Figure 15 is a perspective view showing the first bush member according to the present embodiment.

[0074] Figure 16 is a perspective view showing the damper member according to the present embodiment.

[0075] Figure 17 is a view showing a portion C of Figure 2 enlarged.

[0076] Figure 18 is a perspective view showing the second bush member according to the present embodiment.

[0077] Figure 19 is a perspective view showing a third bush member according to the present embodiment.

[0078] Figure 20 is a cutaway perspective view showing a master cylinder according to the present embodiment.

[0079] Figure 21 is a side direction sectional view of the master cylinder according to the present embodiment, showing a state where the hitching platform is hitched with support by the first limiter.

[0080] Figure 22 is a view showing a portion D of Figure 21 in an enlarged scale.

[0081] Figure 23 is a sectional view showing the master hole and the shaft hole and other directions of the communication hole according to the present embodiment.

[0082] Figure 24 is a sectional view showing other directions of a state where the hitching platform is hitched with support by the first limiter according to the present embodiment.

[0083] Figure 25 is a view showing a portion D of Figure 2 in an enlarged scale.

[0084] Figure 26 is a side view showing other directions of the second limiter according to the present embodiment.

[0085] Figure 27 is a sectional view of A-A' direction of Figure 25 is a side view showing other directions of a state where the second limiter is installed in the first piston. DETAILED DESCRIPTION

[0086] Hereinafter, an embodiment of the present application will be explained in detail with reference to the attached drawings. The following embodiment is provided in order to fully convey the idea of the present application to those skilled in the art to which the present application pertains. The present application is not limited to the following embodiment, and can be realized in other ways. In order to make the present application clear, the illustration of portions irrelevant to the explanation is omitted in the drawings, and the size of the constituent elements is sometimes exaggerated in order to help the understanding.

[0087] Figure 1 is a perspective view showing a master cylinder 1 according to the present embodiment, Figure 2 is a sectional view showing the master cylinder 1 according to the present embodiment. And, Figure 3 is a cutaway perspective view showing the master cylinder 1 according to the present embodiment.

[0088] Referring to Figures 1 to 3According to the master cylinder 1 of the present embodiment, the hydraulic module 110 having the main holes 111, 112 formed in the axial direction inside, the first piston 121 configured to be inserted into the main holes 111, 112 on one side and to protrude outside the hydraulic module 110 on the other side, the second piston 124 inserted into the inside of the first piston 121 on the main holes 111, 112, the elastic member 123 disposed between the first piston 121 and the second piston 124, the mounting seat 140 into which the first piston 121 is inserted and through which the first piston 121 is coupled to the hydraulic module 110, the first seal 116 and the second seal 117 sandwiched between the hydraulic module 110 and the mounting seat 140 to seal the flow path and prevent leakage of the pressurized medium, the cover 127 provided to the first piston 121, and the gap flow path 100 formed by the interval between the first piston 121 and the cover 127.

[0089] The hydraulic module 110 includes the main holes 111, 112 formed in the axial direction and open on the other side (left side with reference to Figure 2 The main holes 111, 112 include the first hole 111 configured such that one side (right side with reference to Figure 2 of the first piston 121 described later is inserted thereinto and is capable of displacement, and the second hole 112 formed on the inside (right side with reference to Figure 2 of the first hole 111 and such that at least a portion of the second piston 124 described later is inserted thereinto and is capable of displacement. That is, the first hole 111 and the second hole 112 are configured in series with reference to the axial direction, and the first hole 111 is configured on the outside of the second hole 112 on the hydraulic module 110, and the second hole 112 is configured on the inside of the first hole 111 on the hydraulic module 110. The diameter of the second hole 112 can be formed to be smaller than the diameter of the first hole 111, whereby, as described later, the second hole 112 is provided with the second step portion 112a formed in a stepped manner on the other side end portion (left side end portion with reference to Figure 2

[0090] In addition to the main holes 111, 112 of the master cylinder 1 according to the present embodiment, the hydraulic module 110 includes various flow paths through which the pressurized medium is delivered. As an example, the other side surface of the hydraulic module 110 can be provided with the hydraulic flow path 119 formed therethrough, and the hydraulic flow path 119 can be connected to the inspection flow path side for inspecting whether the brake device is normally operating, such as leakage of the pressurized medium. That is, the hydraulic module 110 can be understood as a valve module constituting a brake system of a vehicle. The hydraulic module 110 can be fixed and supported on a vehicle body by the support bracket 130. Also, as described later, the hydraulic module 110 can be further provided with the shaft hole 118 through which the shaft 20 of the displacement sensing device (not shown) for sensing displacement of a pedal moves in the axial direction, and the communication hole 118a that communicates the main holes 111, 112 and the shaft hole 118. In the following, the hydraulic module 110 will be described with reference to Figures 20 to 24 ​This will be described in detail.

[0091] It can be configured to be inserted into the first hole 111 on one side (right side with reference to Figure 2 ) of the first piston 121 and be able to displace in the axial direction. The other side of the first piston 121 can be exposed to the outside of the hydraulic module 110, and pass through the mounting seat 140 described later, and be connected to the brake pedal (not shown) through the input rod 11. The first piston 121 includes a main stem portion 121a extending in the axial direction and formed in a cylindrical shape, and a hanging portion 121b formed in a radial direction at one end portion (right side with reference to Figure 2 ) of the main stem portion 121a. The hanging portion 121b can be configured to be housed in the first hole 111, and the outer diameter of the hanging portion 121b can be formed to be larger than the inner diameter of the sub-hole 142 of the mounting seat 140 described later. Thus, when the first piston 121 moves in the return direction (left direction with reference to Figure 2 ), the hanging portion 121b is hung by the mounting protrusion 141a of the mounting seat 140, so that it can be disposed at a certain position in a state where the pedal force on the brake pedal is released. Also, the first piston 121 includes a mounting portion 121d formed in a recess in the axial direction to stably combine the cover 127 and the elastic member 123 on one side (right side with reference to Figure 2 ), a hollow portion 121e extending from the mounting portion 121d, a communication hole 121f formed in a radial direction to communicate the hollow portion 121e and the connection port 149a, and a step surface 121g formed between the mounting portion 121d and the hollow portion 121e as the inner diameter of the mounting portion 121d is formed to be larger than the inner diameter of the hollow portion 121e. A gap flow path 100 is formed by the gap between the first piston 121 and the cover 127, which will be described in detail later.

[0092] It can be configured to insert at least a portion of the second piston 124 into the second hole 112 and be able to displace in the axial direction. The second piston 124 can be displaced by the first piston 121 and the elastic member 123 described later. In the first hole 111, the space divided by the first piston 121 and the second piston 124 described later can constitute a first hydraulic chamber 122, and in the second hole 112, the space divided by the inner side wall and the second piston 124 can constitute a second hydraulic chamber 125. The second hydraulic chamber 125 can be provided with a return spring 126 elastically supporting the second piston 124. Also, between the first piston 121 and the second piston 124, an elastic member 123 that can be extended and contracted can be provided, and the elastic restoring force due to the compression of the elastic member 123 can be provided to the driver as a pedal feel. The other side (left side with reference to Figure 2 ) of the elastic member 123 is provided with a coupling protrusion 123a formed in a protrusion and combined with the cover 127 described later.

[0093] The support bracket 130 is fixed to the vehicle body so as to support the hydraulic module 110 and the mounting seat 140 to be described later. The support bracket 130 can have a coupling portion 131 coupled to the mounting seat 140 to be described later and a support portion 132 fixed to the vehicle body by a fixing plate 133, the coupling portion 131 and the mounting seat 140 are coupled to each other by a plurality of bolts 136, and the support portion 132 and the vehicle body can be coupled and fixed to each other. The support bracket 130 can be formed of a metal material such as steel so as to secure sufficient rigidity.

[0094] The mounting seat 140 can be provided between the hydraulic module 110 and the support bracket 130 so that the first piston 121 exposed to the outside from the hydraulic module 110 is inserted thereinto and the hydraulic module 110 is fixed and supported. The hydraulic module 110 can have a right side surface (a right side surface with reference to the Figure 2 The mounting seat 140 can have a right side surface (a right side surface with reference to the Figure 2 The mounting seat 140 can have a right side surface (a right side surface with reference to the Figure 2 The mounting seat 140 can have a right side surface (a right side surface with reference to the

[0095] Also, the mounting seat 140 has a sub-hole 142 formed in the axial direction. The sub-hole 142 can be formed so that the first piston 121 is inserted and passed therethrough so as to be capable of displacement. A side end portion (a right side end portion with reference to the Figure 2 A side end portion (a right side end portion with reference to the Figure 2 The side end portion of the sub-hole 142 can have a mounting protrusion 141a formed to protrude in the axial direction at the edge thereof in the right side surface (a right side surface with reference to the

[0096] A cover 146 for preventing foreign substances such as dust from flowing into the sub-hole 142 and the inside of the hydraulic module 110 can be provided at the other side end portion of the extension portion 143. One end of the cover 146 can be supported by the extension portion 143 of the mounting seat 140, and the other end can be supported by a support plate 147 fixed to the input rod 11 so as to be capable of expansion and contraction along with the displacement of the input rod 11. Also, the other side end portion of the extension portion 143 can be supported by a piston spring 148 that elastically supports the input rod 11 so as to return the first piston 121. The piston spring 148 can be disposed inside the cover 146, and a noise suppression protrusion 144 for reducing noise and vibration caused by the operation of the piston spring 148 can be provided between the cover 146 and the piston spring 148. Details thereof will be described later. Figure 25 Details thereof will be described later.

[0097] The sub-hole 142 can be provided with a connection port 149a that communicates with a reservoir that houses the pressurized medium. At least one oil seal 149b that prevents leakage of the pressurized medium through the connection port 149a can be provided on one side and the other side of the connection port 149a. The oil seal 149b can be housed in an oil seal groove formed in the inner circumferential surface of the sub-hole 142. The connection port 129a can communicate with the first hydraulic chamber 122 through the gap flow path 100 described later, and the details thereof will be described later with reference to Figures 4 to 7 A detailed description thereof will be given.

[0098] The mounting seat 140 can include a connection flow path 145 that communicates the sub-hole 142 and the hydraulic flow path 119 of the hydraulic module 110. The hydraulic flow path 119 of the hydraulic module 110 can be formed at a distance from the main holes 111, 112, whereby one end of the connection flow path 145 is exposed on one side surface of the provided portion 141 of the mounting seat 140 and the other end is connected to the sub-hole 142 through the port 149a or the like, and can be formed to be inclined at a certain angle with respect to the axial direction. In order to achieve a simple arrangement and assembly, according to the present embodiment, the hydraulic module 110 and the mounting seat 140 are separately manufactured, and then the other side surface of the hydraulic module 110 and the one side surface of the mounting seat 140 are bonded to each other, whereby the flow path of the hydraulic module 110 and the hole of the mounting seat 140 need to be communicated with each other, so the connection flow path 145 is formed to be inclined at a predetermined angle with respect to the axial direction of the mounting seat 140, thereby smoothly maintaining the flow of the pressurized medium.

[0099] A cover 127 that forms the gap flow path 100, 100 is provided between the first piston 121 and the elastic member 123, so as to remove the residual pressure of the pressurized medium present in the first hydraulic chamber 122.

[0100] Figure 4 is a cutaway perspective view showing a state in which the first piston 121 is provided with the cover 127. Also Figure 5 is a perspective view showing the cover 127, Figure 6 is a cutaway perspective view showing the first piston 121. Figure 7 is a view that enlargedly shows Figure 2 A portion of FIG. 1.

[0101] Referring to Figures 4 to 7 , the cover 127 can be sandwiched between the one side portion (the right side portion with respect to Figure 2 and Figure 7 as a reference) of the first piston 121 and the other side portion (the left side portion with respect to Figure 2 and Figure 7 as a reference) of the elastic member 123. The cover 127 includes a main body 127a that is inserted into the mounting portion 121d, a first extension 127b that is formed to extend from the one side end portion (the right side portion with respect to Figure 7The coupling protrusion 123a of the elastic member 123 is inserted into the coupling hole 127c formed in the flange portion 127b formed in the radial direction at the right end portion of the cover 127, thereby achieving installation.

[0102] In order to stably couple the cover 127 to the first piston 121, the outer circumferential surface of the body 127a and the inner circumferential surface of the mounting portion 121d can face or contact each other, and the inner side of the body 127a can be formed hollow to allow easy entry of the elastic member 123. The body 127a can be crimped to the mounting portion 121d, but is not limited thereto and can be coupled in various ways.

[0103] The gap flow path 100 includes a first slit 101 formed in the outer circumferential surface of the body 127a in the axial direction, a second slit 102 formed in the other side surface of the flange portion 127b facing the right end portion of the first piston 121 (with the cover 127 as a reference) in the radial direction and connected to the first slit 101, a third slit 103 formed in the step surface 121g of the first piston 121 in the radial direction and connected to the second slit 102, and a fourth slit 104 formed in the step surface 121g of the first piston 121 in the edge direction and connecting the adjacent third slits 103 to each other. Figure 2 Figure 7 The gap flow path 100 includes a first slit 101 formed in the outer circumferential surface of the body 127a in the axial direction, a second slit 102 formed in the other side surface of the flange portion 127b facing the right end portion of the first piston 121 (with the cover 127 as a reference) in the radial direction and connected to the first slit 101, a third slit 103 formed in the step surface 121g of the first piston 121 in the radial direction and connected to the second slit 102, and a fourth slit 104 formed in the step surface 121g of the first piston 121 in the edge direction and connecting the adjacent third slits 103 to each other.

[0104] With the second slit 102 formed in the flange portion 127b, the second slit 102 can achieve oil pressure communication with the first hydraulic chamber 122. Also, the second slit 102 is connected to the first slit 101 and the third slit 103 and the fourth slit 104, so the first hydraulic chamber 122 can achieve oil pressure communication with the connection port 149a through the hollow portion 121e and the communication hole 121f. The connection port 149a is connected to a reservoir (not shown), so the first hydraulic chamber 122 and the reservoir can achieve oil pressure communication through the gap flow path 100.

[0105] The features of removing the residual pressure of the pressurized medium through the cover 127 and the gap flow path 100 will be described below. When the brake system is switched to a fallback mode in an emergency due to a failure or the like in the normal operation mode of the brake system, the hydraulic pressure of the pressurized medium supplied from a motor or a pump (not shown) or the like of the brake system can be instantaneously transmitted to the first hydraulic chamber 122, so the hydraulic pressure inside the first hydraulic chamber 122 can fail to be released and a residual pressure can remain. In this case, the driver can hardly carefully control the brake of the vehicle, and the pedal force on the brake pedal can also be affected, so the driver can feel an unusual feeling.

[0106] ​Therefore, when residual pressure of the pressurized medium remains in the first hydraulic chamber 122, the residual pressure of the pressurized medium can be discharged to the reservoir through the gap flow path 100 formed by the gap between the first piston 121 and the cover 127. Specifically, the residual pressure in the first hydraulic chamber 122 can be transmitted sequentially through the second gap 102, the first gap 101, and the third gap 103 of the cover 127 to the hollow portion 121e inside the first piston 121. The pressurized medium flowing into the hollow portion 121e is discharged to the reservoir through the connecting hole 121f and the connection port 149a. This not only prevents dragging phenomena, but also maintains a constant stroke of the first piston.

[0107] A first seal and second seals 116 and 117 can be sandwiched between the hydraulic module 110 and the mounting base 140 to prevent leakage of the pressurized medium.

[0108] Figure 8 It is shown in magnification Figure 2 The diagram in part B, Figure 9 It is shown in magnification Figure 8 Refer to the diagram in part E. Figures 2 to 10 The first seal 116 can be clamped onto one side of the mounting base 140 (to... Figure 2 The right side (based on the reference) and the other side of the hydraulic module 110 (based on the reference) Figure 2 Between the left side (as referenced), a sealing element is provided to seal the hydraulic flow path 119 of the hydraulic module 110 and the connecting flow path 145 of the mounting base 140. A first seal 116 extends along the periphery of the opening of the connecting flow path 145 on one side of the mounting base 140 or along the periphery of the opening of the hydraulic flow path 119 on the other side of the hydraulic module 110, thus forming a ring shape. Furthermore, the first seal 116 is inserted into and placed in a first receiving groove 113 recessed along the periphery of the opening of the hydraulic flow path 119 on the other side of the hydraulic module 110, thereby preventing the first seal 116 from dislodging even when a high-pressure pressurized medium is transmitted from the hydraulic flow path 119 or the connecting flow path 145.

[0109] The first seal 116 may have a central first body portion 116a and a first blade portion 116b and a second blade portion 116c respectively provided on both sides of the first body portion 116a, so as to effectively prevent leakage even when a pressurized medium with high pressure is transmitted from the hydraulic flow path 119 or the connecting flow path 145.

[0110] Figure 10 This is a diagram showing the deformation of the first seal 116 due to the hydraulic pressure of the pressurized medium, see reference. Figure 9 as well as Figure 10The first seal 116 can include a first body portion 116a provided centrally to constitute a main body, a first blade portion 116b protruding from the first body portion 116a toward an inner side (an upper side with reference to Figure 9 and Figure 10 ) adjacent to the hydraulic flow path 119, and a second blade portion 116c protruding from the first body portion 116a toward an outer side (a lower side with reference to Figure 9 and Figure 10 ) away from the hydraulic flow path 119. An inner peripheral surface of the first blade portion 116b and an outer peripheral surface of the second blade portion 116c, in other words, portions facing the inner surface of the first housing groove 113, can achieve surface contact with the inner surface of the first housing groove 113, so that leakage of the pressurized medium can be stably prevented even in the case where the pressurized medium is transmitted. For this reason, the inner peripheral surface of the first blade portion 116b and the outer peripheral surface of the second blade portion 116c can each be formed in a shape corresponding to the shape of the inner surface of the first housing groove 113. Thus, as shown, even if the pressurized medium is transmitted from the hydraulic flow path 119 or the connection flow path 145, since the contact area of the outer peripheral surface of the second blade portion 116c with the inner surface of the first housing groove 113 is enlarged, leakage of the pressurized medium can be more effectively suppressed and prevented. Figure 10

[0111] Further, in order to easily deform the first blade portion 116b and the second blade portion 116c when the pressurized medium is transmitted, the thickness (width in the left-right direction with reference to Figure 9 ) of the first blade portion 116b or the second blade portion 116c can be formed to be smaller than the thickness of the first body portion 116a. Specifically, the first body portion 116a can be formed in a circular shape whose cross-sectional shape becomes thicker toward the center, so as to maintain a state in which both sides are in contact with the hydraulic module 110 and the mounting seat 140 on the first housing groove 113, and the thickness of the first blade portion 116b or the thickness of the second blade portion 116c can be formed to be smaller than the diameter of the first body portion 116a. Thus, even if the pressurized medium is transmitted from the hydraulic flow path 119 or the connection flow path 145, first, the hydraulic module 110 and the mounting seat 140 are sealed by the first body portion 116a, and then the first blade portion 116b or the second blade portion 116c easily deforms, rapidly enlarges the contact area with the first housing groove 113, so that leakage of the pressurized medium can be stably prevented.

[0112] Figure 11 is a split perspective view showing the second seal 117 according to the present embodiment, Figure 12 is a view showing an F portion of Figure 8 enlarged, Figure 2 , Figure 11 and Figure 12 ​, the second seal 117 can be sandwiched between one side surface (right side surface with reference to Figure 2 ) of the mounting seat 140 and the other side surface (left side surface with reference to Figure 2 ) of the hydraulic module 110, and configured to seal the main holes 111, 112 and the shaft hole 118 of the hydraulic module 110.

[0113] The shaft hole 118 can be disposed at a distance from the main holes 111, 112 on the hydraulic module 110, and can be configured to extend in the axial direction so that the shaft 20 (not shown) of the displacement sensing device of the brake pedal can be displaced. A communication hole 118a can be formed between the main holes 111, 112 and the shaft hole 118 in the axial direction, and a connecting member for connecting the first piston 121 and the shaft 20 can be accommodated in the communication hole 118a (see Figure 20 and Figure 19 ).

[0114] The second seal 117 can be formed on the other side surface of the hydraulic module 110 along the periphery of the openings of the main holes 111, 112 and the shaft hole 118. Also, the second seal 117 can be inserted and placed in a second accommodation groove 114 recessed on the other side surface of the hydraulic module 110 along the periphery of the openings of the main holes 111, 112 and the shaft hole 118, so that even if a high-pressure pressurized medium is transmitted from the main holes 111, 112 or the shaft hole 118, the second seal 117 can be prevented from being detached.

[0115] The second seal 117 can have a central second body portion 117a, and third and fourth blade portions 117b and 117c provided on both sides of the second body portion 117a, so that even if a high-pressure pressurized medium is transmitted from the hydraulic flow path 119 or the connection flow path 145, leakage can be effectively prevented.

[0116] The second seal 117 can include a second body portion 117a provided at the center to constitute a main body, a third blade portion 117b protruding from the second body portion 117a toward the inside (upper side with reference to Figure 12 ) of the main holes 111, 112 or the shaft hole 118, and a fourth blade portion 117c protruding from the second body portion 117a toward the outside (lower side with reference to Figure 12The fourth blade portion 117c protrudes from the lower side (based on the reference). The inner peripheral surface of the third blade portion 117b and the outer peripheral surface of the fourth blade portion 117c, in other words, the portions facing the inner surface of the second receiving groove 114, can be in surface contact with the inner surface of the second receiving groove 114 to stably prevent leakage of the pressurized medium even when a high-pressure pressurized medium is being transmitted. For this purpose, the inner peripheral surface of the third blade portion 117b and the outer peripheral surface of the fourth blade portion 117c can be formed to correspond to the shape of the inner surface of the second receiving groove 114. Thus, with Figure 10 Similarly, the first seal 116 shown increases the contact area between the outer peripheral surface of the fourth blade portion 117c and the inner surface of the second receiving groove 114 even when pressurized medium is transmitted from the main bore 111, 112 or the shaft bore 118, thereby more effectively suppressing and preventing leakage of the pressurized medium.

[0117] Furthermore, in order to facilitate the deformation of the third blade portion 117b and the fourth blade portion 117c during the transmission of pressurized medium, the thickness of the third blade portion 117b or the fourth blade portion 117c (as shown in the figure) is... Figure 12 The width in the left-right direction (based on the reference) can be made smaller than the thickness of the second body portion 117a. Specifically, the second body portion 117a can be formed into a circular shape with a cross-sectional shape that thickens towards the center, so as to maintain contact between the hydraulic module 110 and the mounting base 140 on both sides of the second receiving groove 114, and the thickness of the third blade portion 117b or the fourth blade portion 117c can be made smaller than the diameter of the second body portion 117a. Thus, even if pressurized medium is transmitted from the main holes 111, 112 or the shaft hole 118, the second body portion 117a first seals the space between the hydraulic module 110 and the mounting base 140, and then the third blade portion 117b or the fourth blade portion 117c can easily deform, rapidly increasing the contact area with the second receiving groove 114, thereby stably preventing leakage of the pressurized medium.

[0118] The bushing assembly is configured to guide the first piston 121 and the second piston 124 to move smoothly back and forth while preventing excessive friction and scratches between the piston and the bore.

[0119] Figure 13 as well as Figure 14 It is shown in magnification Figure 2 The diagram in part A, Figure 15 This is a perspective view showing the first bushing component 151. Figure 16 This is a perspective view showing the shock absorber component 152.

[0120] Reference Figure 2 , Figure 3 , Figures 13 to 16 The first bushing component 151 and one side of the first piston 121 (with Figure 2, Figure 13 as well as Figure 14 Adjacent to the right side of the reference point, it is configured to guide the forward and backward movement of the first piston 121 to achieve stable sliding while preventing wear and damage caused by contact with the mounting base 140. One end of the secondary hole 142 (with...) Figure 13 as well as Figure 14 The right end portion (based on the reference) has a stepped first step portion 142a with an inner diameter larger than the inner diameter of the secondary hole 142. The first bushing member 151 is annular and its outer peripheral surface may abut against the inner peripheral surface of the first step portion 142a. The outer peripheral surface of the first bushing member 151 can be pressed against the inner peripheral surface of the first step portion 142a to stably support the first bushing member 151 on the first step portion 142a and prevent the first bushing member 151 from dislodging. The first bushing member 151 may be made of plastic, and the diameter of the inner peripheral surface of the first bushing member 151 may be formed to correspond to the diameter of the outer peripheral surface of the main body 121a of the first piston 121.

[0121] Shock absorber component 152 is configured to return the first piston 121 (to) Figure 2 , Figure 13 as well as Figure 14 To prevent noise and vibration caused by impact between the first piston 121 and the mounting base 140 when moving to the left (based on the reference direction). The shock absorber component 152 can be coupled to one end of the outer circumferential surface of the first piston 121 (to prevent noise and vibration caused by impact between the first piston 121 and the mounting base 140). Figure 13 as well as Figure 14 The shock absorber component 152 is positioned adjacent to the right end of the first piston 121 (based on the reference point) and can be made of an elastically deformable material to mitigate the impact from the contact between the first piston 121 and the mounting base 140. The shock absorber component 152 can be inserted into and closely fitted into a circumferentially recessed groove on the outer circumferential surface of the first piston 121, so that the shock absorber component 152 can be stably supported on the first piston 121 while preventing detachment. Furthermore, the shock absorber component 152 can be positioned on one side (with the reference point being the right end of the first piston 121). Figure 13 as well as Figure 14 The right side (based on the reference) is supported by the mounting portion 121b of the first piston 121, and the other side (with) Figure 13 as well as Figure 14 The left side (based on the reference) can face and contact the first bushing component 151, and the shock absorber component 152 can enter the inner side of the first step portion 142a as the first piston 121 moves back and forth. The shock absorber component 152 may be provided with an outer groove 152a formed by a recess on at least one of the sides to facilitate easy and rapid compression and recovery.

[0122] The second bushing component 160 is designed to guide the reciprocating movement of the second piston 124 while preventing wear and damage caused by contact with the hydraulic module 110.

[0123] Figure 17 is a view showing a C portion of Figure 2 , Figure 18 is a perspective view showing the second bush member 160.

[0124] Referring to Figure 2 , Figure 3 , Figure 17 and Figure 18 , the second bush member 160 can be provided between the second piston 124 and the second hole 112. The other side end portion (the left side end portion with reference to Figure 17 ) of the second hole 112 is provided with a second stepped portion 112a formed in a stepped shape so as to have an inner diameter greater than that of the second hole 112, and the second bush member 160 is formed in a ring shape and can be provided so that the outer circumferential surface thereof is in abutment with the inner circumferential surface of the second stepped portion 112a. The outer circumferential surface of the second bush member 160 can be crimped to the inner circumferential surface of the second stepped portion 112a so as to stably support the second bush member 160 on the second stepped portion 112a and prevent the second bush member 160 from being detached. The second bush member 160 can be formed of a plastic material, and the diameter of the inner circumferential surface of the second bush member 160 can be formed to correspond to the diameter of the outer circumferential surface of the second piston 124. Also, the second bush member 160 can include an inner groove portion 160a formed in a recessed shape in the circumferential direction of the inner circumferential surface so as to smoothly enable the sliding of the second piston 124. The direct friction between the second piston 124 and the hydraulic module 110 is reduced by the second bush member 160, so that scratching and damage can be prevented, and product durability can be improved.

[0125] The third bush member 170 is provided adjacent to the other side (the left side with reference to Figure 2 ) of the first piston 121 so as to guide the reciprocating movement of the first piston 121 while being provided to prevent abrasion and damage caused by contact with the mounting seat 140.

[0126] Figure 19 is a perspective view showing the third bush member 170, referring to Figure 2 and Figure 19 , the other side end portion (the left side end portion with reference to Figure 2The third step portion 142b is formed in a stepped shape with an inner diameter larger than that of the sub hole 142, and the third bushing member 170 can be inserted into the third step portion 142b. Like the first bushing member 151, the third bushing member 170 is formed in a ring shape, and can be configured such that an outer peripheral surface thereof abuts against an inner peripheral surface of the third step portion 142b. The outer peripheral surface of the third bushing member 170 can be crimped to the inner peripheral surface of the third step portion 142b, so as to stably support the third bushing member 170 on the third step portion 142b and prevent the third bushing member 170 from coming off. The third bushing member 170 can be made of a plastic material, and the diameter of the inner peripheral surface of the third bushing member 170 can be formed to correspond to the diameter of the outer peripheral surface of the stem portion 121a of the first piston 121.

[0127] Figure 20 is a cutaway perspective view of the hydraulic module 110. Figure 21 is a side cross-sectional view of the master cylinder 1, showing a state in which the hooking platform 181 is hooked to the first limiter 182, Figure 22 is an enlarged view showing the G portion of Figure 21 , and Figure 23 is a cross-sectional view in another direction showing the main holes 111, 112 and the shaft hole 118, and the communication hole 118a, Figure 24 is a cross-sectional view in another direction showing a state in which the hooking platform 181 is hooked to the first limiter 182.

[0128] Referring to Figures 20 to 24 , the hydraulic module 110 includes a shaft hole 118 in which a shaft 20 of a displacement sensing device (not shown) that senses displacement of a pedal moves in a shaft direction, and a communication hole 118a that communicates the main holes 111, 112 and the shaft hole 118. The shaft 20 is supported by a magnet or is made of a magnet, so that a sensor provided in the displacement sensing device senses a change in magnetic force or a change in magnetic flux density of the magnet, thereby being able to sense displacement of the first piston 121. Also, the shaft 20 and the first piston 121 can be connected and combined by a fastening member 30 that can move along the communication hole 118a. In this way, the main holes 111, 112 in which the first piston and the second piston 124 move inside the hydraulic module 110 and the shaft hole 118 in which the shaft 20 moves are communicated with each other by the communication hole 118a, so that no additional sealing member for sealing each hole is needed, the number of component elements is reduced, and the structure can be simplified. Also, the main holes 111, 112 and the shaft hole 118 can be disposed close to each other, so that miniaturization and lightening of the hydraulic module 110 can be achieved.

[0129] A hooking stage 181 which is expanded or protruded in a radial direction can be provided on the outer circumferential surface of the second piston 124, and a first limiter 182 which hooks and supports the hooking stage 181 can be provided on the inner circumferential surface of the main hole 111, 112. The outer diameter of the hooking stage 181 is formed to be greater than the inner diameter of the first limiter 182, so that the hooking stage 181 can be hooked in the first limiter 182. Specifically, the other side end (left side end with reference to Figure 21 and 18) of the hooking stage 181 contacts the one side end (right side end with reference to Figure 21 and 18) of the first limiter 182, so that the moving distance of the second piston 124 in the return direction is limited, and the working stroke can be uniformly maintained, so that the second piston 124 can be disposed at a certain position in a state where the pedal force on the brake pedal is released.

[0130] The first limiter 182 is installed on the inner circumferential surface of the main hole 111, 112, and can be expanded or protruded toward the inside of the main hole 111, 112 so as to hook and support the hooking stage 181. The first limiter 182 can have an open portion 182a which is formed in a ring shape and one side of which is open, and the communication hole 118a can be located inside the open portion 182a. Thus, even if the piston and the fastening member 30 move, interference with the first limiter 182 can be prevented. The first limiter 182 is made of a plastic material, so that noise and vibration generated at the time of contact with and collision against the hooking stage 181 can be suppressed. Also, the diameter of the inner circumferential surface of the first limiter 182 is formed to correspond to the diameter of the outer circumferential surface of the portion of the second piston 124 which faces it, so that sagging due to the weight of the second piston 124 can be prevented.

[0131] In order to stably support and install the first limiter 182 on the main hole 111, 112, specifically, the inner circumferential surface of the first hole 111 can be provided with a first limiting groove 183 which is recessed in a circumferential direction. The first limiter 182 is inserted and placed in the first limiting groove 183, so that it can be stably supported at a certain position and prevented from being detached. The first limiting groove 183 can include a detachment preventing portion 184 which is protruded toward the inside of the open portion 182a and faces both ends of the open portion 182a of the first limiter 182, and the rotation of the first limiter 182 is prevented by the detachment preventing portion 184, so that the first limiter 182 can be prevented from entering the communication hole 118a side. Also, the inner circumferential surface of the detachment preventing portion 184 can be formed to have continuity with the inner circumferential surface of the main hole 111, 112 or the first hole 111, so that the piston can be prevented from being interfered with by the detachment preventing portion 184. In Figure 22 and Figure 23The example shown in FIG. 10 illustrates that the anti-disengagement portion 184 is formed in a curved shape at both ends thereof by grinding in order to easily manufacture the anti-disengagement portion 184 on the hydraulic module 110, but this is only an example for helping understanding of the present application and is not limited to this shape. Depending on the manufacturing method, the shape of both ends of the anti-disengagement portion 184 can be variously formed.

[0132] Figure 25 is a view enlargedly showing Figure 2 D portion of FIG. 10.

[0133] Referring to Figure 25 , the support plate 147 can be fixed to the input rod 11. The cover 146 which is extended and contracted as the input rod 11 is displaced can be supported on the support plate 147, and the other end of the piston spring 148 which elastically supports the input rod 11 and the first piston 121 can be supported. The support plate 147 can be formed in a plate shape and fixed to the outer circumferential surface of the input rod 11 so as to stably support the cover 146 and the piston spring 148. The cover 146 can be formed of a material such as an elastically deformable rubber.

[0134] On the other hand, the input rod 11 and the first piston 121 are displaced in a forward and backward direction by the operation of the brake pedal, and the cover 146 is extended and contracted by the forward and backward displacement of the input rod 11. In order to smoothly deform the cover 146, the inside of the cover 146 needs to be communicated with the outside. In this case, if foreign matter such as dust or moisture flows into the inside of the cover 146, it can adversely affect the performance of the components such as the input rod 11 and the piston spring 148, and the possibility of the foreign matter flowing into the inside of the mounting seat 140 or the hydraulic module 110 increases, thereby posing a risk of reducing the performance and durability of the product.

[0135] To this end, the support plate 147 includes at least one exhaust hole 147a formed to communicate the inside and the outside of the cover 146, and the exhaust hole 147a can be formed to be inclined at a predetermined angle with respect to the axial direction. The inside and the outside of the cover 146 are communicated through the exhaust hole 147a, thereby enabling smooth deformation of the cover 146, and the exhaust hole 147a is formed to be inclined at a predetermined angle, thereby preventing foreign matter such as dust from directly intruding into the inside of the cover 146, so that the inflow of the foreign matter can be suppressed.

[0136] On the other hand, when the pedal force of the brake pedal is released or the brake is released after the input rod 11 and the first piston 121 are advanced by the operation of the brake pedal, the input rod 11 and the first piston 121 are returned to the original positions by the piston spring 148. At this time, the piston spring 148 is compressed and then expanded again, and a shake occurs due to the elastic restoring force of the piston spring 148 itself, thereby generating noise and vibration.

[0137] To this end, the master cylinder 1 according to the present embodiment is provided with a noise suppression protrusion 144 in order to reduce noise and vibration generated in the operation of the piston spring 148.

[0138] Figure 26 is a side view showing the other direction of the second limiter 190, Figure 27 is Figure 25 is a sectional view of the A-A' direction of

[0139] Referring to Figures 25 to 27 , the noise suppression protrusion 144 can be provided on the inner circumferential surface of the cover 146. The noise suppression protrusion 144 is formed to protrude inward on the inner circumferential surface of the cover 146, thereby maintaining contact with at least a portion of the outer circumferential surface of the piston spring 148. The noise suppression protrusion 144 can be integrally formed with the cover 146, and thus, like the cover 146, the noise suppression protrusion 144 can be composed of a material that can be elastically deformed, such as rubber. The noise suppression protrusion 144 is formed to protrude inward on the inner circumferential surface of the cover 146 or to extend to contact at least one portion of the outer circumferential surface of the piston spring 148, thereby absorbing the resonance generated by the piston spring 148 by the noise suppression protrusion 144, and thus, noise and vibration can be reduced. The noise suppression protrusion 144 can be provided to maintain a contact state with at least one portion of the outer circumferential surface of the piston spring 148 regardless of whether the piston spring 148 is compressed or expanded.

[0140] The second limiter 190 can be provided on the outer circumferential surface of the other side (the left side with reference to the Figure 25 ) of the first piston 121 exposed to the outside of the mounting seat 140. The second limiter 190 can be installed to radially expand or protrude from the outer circumferential surface of the first piston 121, and the second limiter 190 is formed in a ring shape and has a receiving portion through which the first piston 121 passes on the inside and a mounting opening 195 formed on the open side. Thus, as the first piston 121 advances as the brake pedal is operated, the second limiter 190 is hooked to the other side end (the left side end with reference to the Figure 25 ) of the mounting seat 140, thereby limiting the movement distance in the advancing direction of the first piston 121, and thus, the operating stroke can be uniformly maintained. The second limiter 190 can be inserted and seated in the second limiter 190 groove 121c formed to be recessed in the circumferential direction on the outer circumferential surface of the first piston 121, so as to be stably supported on the outer circumferential surface of the first piston 121.

[0141] On the other hand, noise and vibration can occur when the second limiter 190 contacts the other side end of the mounting seat 140. In order to reduce the noise and vibration that occurs at this time, the accommodation portion of the second limiter 190 can be divided into two parts having different diameters. Specifically, the accommodation portion can be divided into a first accommodation portion 191 having a first radius d1 with the first center 191a as a reference and a second accommodation portion 192 having a second radius d2 with the second center 192a as a reference, the second center 192a is more centrifugal than the first center 191a in the direction closer to the mounting opening 195, and the second radius d2 can be formed to be smaller than the first radius d1. Thus, when the second limiter 190 is mounted on the outer circumferential surface of the first piston 121, the inner circumferential surface of the second limiter 190 and the outer circumferential surface of the first piston 121 are combined with each other through three contact points 193. The second limiter 190 and the first piston 121 are combined with each other through the three contact points 193, thereby realizing the fastening force between the two component elements while minimizing the contact area, so that even if the second limiter 190 is in contact with the mounting seat 140 and shakes on the outer circumferential surface of the first piston 121, the generation of noise and vibration can be suppressed.

Claims

1. A master cylinder, comprising: The hydraulic module has a main bore formed along the axial direction inside; The first piston has one side inserted into the main hole and capable of displacement, and the other side exposed to the outside of the hydraulic module and connected to the brake pedal. The mounting base has an internal secondary hole and a connection port. The secondary hole is formed along the axial direction and allows the first piston to be inserted and pass through it for displacement. The connection port connects the secondary hole to the reservoir. A cover, which is located on one side of the aforementioned first piston; and An intermittent flow path is formed by the gap between the first piston and the cover, so as to connect the first hydraulic chamber divided by the first piston on the main bore and the connection port. The aforementioned first piston includes a mounting portion recessed along the axial direction on one side. The aforementioned cover includes a main body that is inserted into the aforementioned mounting portion and a flange portion that expands radially from one end of the main body. The aforementioned gap flow path includes: The first gap is formed by a recess along the axial direction on the outer peripheral surface of the aforementioned main body; as well as The second gap is formed radially recessed on the flange portion on the other side facing one end of the first piston and is connected to the first gap.

2. The master cylinder according to claim 1, wherein, The aforementioned first piston also includes: A hollow section, which extends from the aforementioned mounting section; A connecting hole, which connects the aforementioned hollow portion and the aforementioned connecting port; and The stepped surface is formed between the aforementioned mounting portion and the aforementioned hollow portion, facing the other side of the aforementioned main body. The aforementioned gap flow path also includes a third gap, which is formed by a recess in the aforementioned stepped surface along the aforementioned radial direction and is connected to the aforementioned second gap.

3. The master cylinder according to claim 2, wherein, Multiple third gaps are formed on the aforementioned stepped surface. The aforementioned gap flow path also includes a fourth gap, which is formed by a recess along the edge direction on the aforementioned stepped surface to connect the plurality of the aforementioned third gaps to each other.

4. The master cylinder according to claim 1, wherein, Also includes: The second piston is inserted into the inside of the first piston through the main hole and is able to move. as well as An elastic component, located between the first piston and the second piston, provides pedal feel. The other end of the aforementioned elastic component is inserted into and joined to the inner side of the aforementioned main body.

5. The master cylinder according to claim 4, wherein, The aforementioned elastic component includes a connecting protrusion formed on the other side. The cover also includes a connecting hole formed through the body for inserting the connecting protrusion.

6. The master cylinder according to claim 1, wherein, include: An input lever, one end of which is connected to the first piston and the other end of which is connected to the brake pedal; A support plate, which is fixed to the aforementioned input rod; as well as The cover, supported at one end by the aforementioned mounting base and at the other end by the aforementioned support plate, is telescopic. The aforementioned support plate includes an exhaust port, which is formed to connect the interior and exterior of the aforementioned cover. The aforementioned vent is formed at a certain angle relative to the aforementioned axial direction.

7. The master cylinder according to claim 1, wherein, The aforementioned secondary hole also includes a first stepped portion formed in a stepped shape at one end. The aforementioned master cylinder also includes: The first bushing component is inserted into the first stepped portion to guide the reciprocating movement of the first piston.

8. The master cylinder according to claim 7, wherein, Also includes: The shock absorber component, at least a portion of which can enter the inner side of the aforementioned first step, The shock absorber component includes at least one side of one side and the other side, which includes a plurality of recessed outer grooves.

9. The master cylinder according to claim 4, wherein, The aforementioned main holes include: The first hole is formed to allow the aforementioned first piston to be displaced; and A second hole is formed inside the first hole, configured to allow at least a portion of the second piston to be displaced, and its diameter is smaller than that of the first hole. The second hole includes a second stepped portion, which is formed in a stepped shape at the end opposite to the first hole. The aforementioned master cylinder also includes: The second bushing component, which is inserted into the second stepped portion, guides the reciprocating movement of the second piston. The aforementioned second bushing component is formed in a ring shape, and includes an inner groove formed in the circumferential direction on its inner circumferential surface.

10. The master cylinder according to claim 1, wherein, The aforementioned secondary hole includes a third stepped portion, which is formed in a stepped shape at the other end. The aforementioned master cylinder also includes: The third bushing component is inserted into the third step portion to guide the reciprocating movement of the first piston.

11. The master cylinder according to claim 8, wherein, The aforementioned first piston includes: The main stem, which extends along the axial direction; and The connecting part is formed by radial expansion at one end of the aforementioned main body. One side of the aforementioned shock absorber component is supported by the aforementioned mounting portion, and the other side is able to face and contact the aforementioned first bushing component.

12. The master cylinder according to claim 1, wherein, The aforementioned mounting base includes a mounting protrusion extending along the edge of one end of the aforementioned secondary hole. The outer peripheral surface of the aforementioned mounting protrusion faces or contacts the inner peripheral surface of the aforementioned main hole.

13. The master cylinder according to claim 4, wherein, The aforementioned hydraulic module also includes an axial hole formed along the axial direction and a connecting hole connecting the main hole and the axial hole. The aforementioned second piston includes a mounting platform protruding from its outer peripheral surface. The aforementioned master cylinder also includes: A first limiter is provided on the inner circumferential surface of the main hole, through which the mounting platform is mounted and supported, and has an opening on one side. The aforementioned connecting hole is located inside the aforementioned opening.

14. The master cylinder according to claim 13, wherein, The aforementioned main hole also includes a first limiting groove formed by a circumferential recess on its inner circumferential surface. At least a portion of the first limiter is inserted into and placed in the first limit groove.

15. The master cylinder according to claim 14, wherein, The aforementioned first limiting groove includes an anti-detachment part that protrudes and is formed inside the aforementioned opening.

16. The master cylinder according to claim 1, wherein, include: An input lever, one end of which is connected to the first piston and the other end of which is connected to the brake pedal; A support plate, which is fixed to the aforementioned input rod; The cover, one end of which is supported by the aforementioned mounting base and the other end by the aforementioned support plate, is telescopic; and A piston spring, one end of which is supported by the aforementioned mounting base and the other end by the aforementioned support plate, thereby elastically supporting the aforementioned input rod or the aforementioned first piston. The inner circumferential surface of the cover is provided with a noise-suppressing protrusion that protrudes inward so as to maintain contact with at least a portion of the outer circumferential surface of the piston spring.

17. The master cylinder according to claim 16, wherein, Also includes: The second limiter is provided on the outer peripheral surface of the first piston, at a portion that protrudes towards the outside of the mounting base. The second limiter includes: a receiving portion located on the inner side for the passage of the first piston; And an installation opening formed on one side.

18. The master cylinder according to claim 17, wherein, The outer circumferential surface of the aforementioned first piston is formed into a cylindrical shape. The aforementioned receiving portion includes a first center, a first receiving portion having a first radius from the first center, a second center, and a second receiving portion having a second radius from the second center. The second circle is formed by being closer to the mounting opening than the first circle. The second radius is smaller than the first radius.

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