Hydraulic pressure generating device

Abstract

The present invention provides a hydraulic pressure generating device, comprising: a cylinder tube; a plurality of pistons that displace within the cylinder tube; a pressure chamber which communicates with a hollow portion formed in the piston, is formed in the cylinder, and causes the brake fluid to generate a hydraulic pressure corresponding to the displacement of the piston; a reservoir for storing brake fluid and communicating with the inside of the cylinder through a discharge port; a plurality of first communication holes formed in the peripheral wall of the hollow part and switching between a communication state and a non-communication state with the discharge port by the displacement of the piston; and a second communication hole which is formed in the peripheral wall of the hollow part, is located on the rear side of the first communication hole in the advancing direction of the piston, and is used for switching a communication state and a non-communication state with the discharge port. The total flow rate of the brake fluid that can flow through the second communication hole per unit time is smaller than the total flow rate of the brake fluid that can flow through the first communication hole per unit time. When the hydraulic pressure generating device is in an initial state, the first communicating hole is in a non-communicating state, and the second communicating hole is in a communicating state.

Description

Technical Field

[0001] The present invention relates to a hydraulic pressure generating device, and more particularly to a hydraulic pressure generating device capable of shortening the time required for the brake hydraulic pressure to rise and improving the responsiveness of the braking force generation. Background Art

[0002] In an electric booster type brake system, an electric hydraulic pressure generating device uses an electric motor to drive a piston slidably mounted back and forth in a cylinder to generate brake hydraulic pressure. However, due to the driving of the electric motor, there is a loss stroke of the piston from when the piston starts to advance until brake hydraulic pressure is generated in the cylinder, and thus, there is a problem of reduced responsiveness of the braking force generation. Specifically, when the piston starts to advance and the valve is closed instantaneously, brake hydraulic pressure is generated in the cylinder. However, when the piston starts to advance until the valve is closed, no brake fluid pressure is generated, and during this period, the advancing distance of the piston becomes the loss stroke.

[0003] The object of Patent Document 1 is to be able to easily adjust the initial position of the piston of the brake hydraulic pressure generating device while minimizing the loss stroke of the piston. Therefore, the brake hydraulic pressure generating device has an adjustment member for adjusting the initial position in the axial direction of the piston. By minimizing the loss stroke from when the piston starts to move forward until brake hydraulic pressure is generated, the responsiveness of the braking force generation is improved without controlling the actuator and adjusting the initial position every time the piston operates.

[0004] [Prior Art Documents]

[0005] [Patent Documents]

[0006] [Patent Document 1]: Japanese Patent No.: JP 4953832B Summary of the Invention

[0007] [Problems to be Solved by the Invention]

[0008] In Patent Document 1, although the initial position can be easily adjusted, brake hydraulic pressure is generated only after the piston starts to advance until all the valves are closed. Therefore, there is a problem in shortening the time required for the brake hydraulic pressure to rise. In recent years, the responsiveness of electric brakes has been emphasized, and rapid pressure increase is required during emergency braking.

[0009] [Technical Means for Solving the Problems]

[0010] In order to solve the above problems, the present invention provides a hydraulic generating device that can shorten the time required for the brake hydraulic pressure to rise and improve the responsiveness of the braking force generation.

[0011] According to an aspect of an embodiment of the present invention, there is provided a hydraulic generating device including: a cylinder; a plurality of pistons linked to a brake pedal and displaced within the cylinder by a motor as the brake pedal is actuated; a pressure chamber formed within the cylinder and communicating with a hollow portion formed in the piston, the pressure chamber generating a hydraulic pressure corresponding to the displacement of the piston; a reservoir storing the brake fluid and communicating with the interior of the cylinder via a drain port; a plurality of first communication holes formed in the peripheral wall of the hollow portion, the communication state and non-communication state with the drain port being switched by the displacement of the piston; and a second communication hole formed in the peripheral wall of the hollow portion of the piston provided with the first communication hole, the second communication hole being located rearward in the advancing direction of the piston of the first communication hole, the second communication hole switching the communication state and non-communication state with the drain port; wherein the total flow rate of the brake fluid that can flow through the second communication hole per unit time is less than the total flow rate of the brake fluid that can flow through the first communication hole per unit time; in an initial state of the hydraulic generating device, the first communication hole is in the non-communication state and the second communication hole is in the communication state.

[0012] In an embodiment of the hydraulic generating device of the present invention, there is further included: a controller for controlling the driving amount of the motor, the controller configured to: when the piston returns from a pressurized state to the initial state, after the piston moves to a position where the first communication hole and the drain port become in the communication state, return to the initial state.

[0013] In an embodiment of the hydraulic generating device of the present invention, there is further included: a Vehicle Stability Assist (VSA) for supporting the stabilization of vehicle behavior; and a wheel brake cylinder, wherein the pressure chamber is connected to the wheel brake cylinder via the Vehicle Stability Assist, the controller configured to: when the Vehicle Stability Assist operates, move the piston to a position where the first communication hole and the drain port become in the communication state.

[0014] In an embodiment of the hydraulic generating device of the present invention, the total flow rate of the brake fluid that can flow through the second communication hole provided in each of the plurality of pistons per unit time is the same.

[0015] [Effects of the Invention]

[0016] The hydraulic generating device according to an embodiment of the present invention has at least the following technical effects:

[0017] In the initial state, the second communication hole communicates with the discharge port, maintaining an open state to the atmosphere. Since the total flow rate of the brake fluid that can flow through the second communication hole per unit time is less than the total flow rate of the brake fluid that can flow through the first communication hole per unit time, less brake fluid flows out, the loss stroke can be shortened, and it is easier to build up hydraulic pressure. Here, the loss stroke refers to the time required for the brake hydraulic pressure to rise after the valve closes, rather than the stroke amount of the piston.

[0018] By temporarily forming a state where the first communication hole communicates with the discharge port, the pressure in the pressure chamber can be reduced to the open state to the atmosphere in a short time.

[0019] When the vehicle behavior stabilizer operates, the first communication hole and the discharge port are in a communicating state, allowing more brake fluid to flow to one side of the vehicle behavior stabilizer than in the initial state, so that the vehicle behavior stabilizer operates smoothly.

[0020] It is possible to match the timing of applying pressure to each pressure chamber and the timing of applying braking.

[0021] To make the above features and advantages of the present invention more obvious and understandable, the following specific embodiments are given and described in detail in conjunction with the accompanying drawings. Description of the Drawings

[0022] Figure 1 is a schematic diagram of a hydraulic generating device according to an embodiment of the present invention.

[0023] Figure 2 is Figure 1 an enlarged schematic diagram of part A of

[0024] Figure 3 is a side view schematic diagram of a piston according to an embodiment of the present invention.

[0025] Figure 4 is a side view schematic diagram of a piston according to another embodiment of the present invention.

[0026] Figure 5 is a schematic diagram of the operation of a piston according to an embodiment of the present invention.

[0027] Figure 6 is according to Figure 5 the operation of the piston, a relationship diagram between the piston stroke and time in the hydraulic generating device, where the vertical axis is the piston stroke and the horizontal axis is time (seconds).

[0028] Description of the Reference Numerals:

[0029] 100: Hydraulic generating device

[0030] 110: Cylinder barrel

[0031] 112: Side wall of the cylinder barrel

[0032] 120: Piston

[0033] 120A: Hollow portion

[0034] 130: Pressure chamber

[0035] 140: Reservoir

[0036] 150: Drain port

[0037] 160: First communication hole

[0038] 170: Second communication hole

[0039] 180: Controller

[0040] 192: Vehicle behavior stabilizer

[0041] 194: Wheel brake cylinder

[0042] A: Portion

[0043] BP: Brake pedal

[0044] EM: Electric motor

[0045] FWD, REV, L: Arrow

[0046] MS: Master cylinder barrel

[0047] SP: Sealing position

[0048] O: Sealing member Detailed implementation mode

[0049] Hereinafter, exemplary embodiments of the present invention will be described based on the drawings. It should be noted that in each of the embodiments described below, the same reference numerals are assigned to common parts, and repeated descriptions are omitted. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0050] Figure 1 It is a schematic diagram of a hydraulic generating device according to an embodiment of the present invention. Figure 2 is Figure 1 an enlarged schematic diagram of part A of Figure 2 . In

[0051] Please refer to Figure 1 and Figure 2, the hydraulic pressure generating device 100 may include: a cylinder 110, a piston 120, a pressure chamber 130, a reservoir 140, a discharge port 150, a first communication hole 160, and a second communication hole 170. Hereinafter, the detailed structure of the hydraulic pressure generating device 100 will be further described.

[0052] A plurality of pistons 120 are linked to the brake pedal BP and displaced within the cylinder 110 by the electric motor EM as the brake pedal BP operates.

[0053] The pressure chamber 130 communicates with the hollow portion 120A formed in the piston 120 and is formed within the cylinder 110, generating a hydraulic pressure corresponding to the displacement of the piston 120 in the brake fluid.

[0054] Please refer to Figure 2 , on the inner peripheral wall of the cylinder 110, a sealing member O is provided. The sealing member O may be an annular sealing structure. The pressure chamber 130 located on the left side of Figure 2 is a space divided by the sealing member O and the side wall 112 of the cylinder 110, and, the pressure chamber 130 located in the middle of Figure 2 is a space divided by two sealing members O, O.

[0055] The reservoir 140 accumulates the brake fluid and communicates with the inside of the cylinder 110 via the discharge port 150.

[0056] A plurality of first communication holes 160 are formed on the peripheral wall of the hollow portion 120A, and the communication state and non-communication state with the discharge port 150 are switched by the displacement of the piston 120.

[0057] The second communication hole 170 is formed on the peripheral wall of the hollow portion 120A of the piston 120 where the first communication hole 160 is provided, and the second communication hole 170 is located on the rear side in the advancing direction of the piston 120 of the first communication hole 160. The second communication hole 170 switches the communication state and non-communication state with the discharge port 150; wherein, the total flow rate of the brake fluid that can flow through the second communication hole 170 per unit time is less than the total flow rate of the brake fluid that can flow through the first communication hole 160 per unit time; in the initial state of the hydraulic pressure generating device 100, the first communication hole 160 is in the non-communication state, and the second communication hole 170 is in the communication state.

[0058] Figure 3 is a side view schematic diagram of a piston according to an embodiment of the present invention. Please refer to Figure 3 , showing the piston 120 in the initial state (non-operating state) and located at the sealing position SP. In Figure 3 , the second communication hole 170 is located on the rear side in the advancing direction of the piston 120 of the first communication hole 160 ( Figure 3 arrow FWD of

[0059] Figure 4 This is a side view of the piston of another embodiment of the present invention. Please refer to Figure 4 , which shows the piston 120 in its initial state (non-operating state) and located at the sealing position SP. In Figure 4 , the second communication hole 170 has a shape with a relatively large part of its radius. For example, the second communication hole 170 can be a long hole, an oval hole, or a rectangular hole. In Figure 4 , in the initial state, at least a part of the second communication hole 170 is disposed at a position communicating with the discharge port 150 (refer to Figure 2 ) behind the sealing position SP. Here, behind the sealing position SP means the rear side in the direction opposite to the traveling direction of the arrow FWD of Figure 4 .

[0060] In Figure 3 and Figure 4 of the embodiment, the number of the second communication holes 170 is one. However, the present invention does not limit the number of the second communication holes 170. In other embodiments, the number of the second communication holes 170 can also be multiple. When the number of the second communication holes 170 is smaller, the loss stroke is smaller. Accordingly, an appropriate number of the second communication holes 170 can be set.

[0061] In addition, the total flow rate of the brake fluid that can flow through the first communication hole 160 per unit time refers to the total flow rate of the brake fluid flowing through a plurality of the first communication holes 160 per unit time. Furthermore, the total flow rate of the brake fluid that can flow through the second communication hole 170 per unit time refers to the total flow rate of the brake fluid flowing through at least one of the second communication holes 170 per unit time.

[0062] As described above, in the initial state, the second communication hole 170 communicates with the discharge port 150 and maintains the state of open atmosphere. Since the total flow rate of the brake fluid that can flow through the second communication hole 170 per unit time is smaller than the total flow rate of the brake fluid that can flow through the first communication hole 160 per unit time, the outflow of the brake fluid is less, the loss stroke can be shortened, and the hydraulic pressure can be more easily established.

[0063] Figure 5 This is a schematic diagram of the operation of the piston of the embodiment of the present invention. Figure 6 This is a graph showing the relationship between the piston stroke and time in the hydraulic generating device according to the operation of the piston of Figure 5 , where the vertical axis is the piston stroke and the horizontal axis is time (seconds).

[0064] Please refer to Figure 1 , Figure 5 and Figure 6, the hydraulic pressure generating device 100 may further include: a controller 180 configured to control the driving amount of the electric motor EM. The controller 180 is configured such that when the piston 120 returns from the pressurized state (such as state ② shown in Figure 5 ) to the initial state (such as state ① shown in Figure 5 ), after the piston 120 moves to a position where the first communication hole 160 and the discharge port 150 are in a communicating state (such as state ③ shown in Figure 5 ), it returns to the initial state (such as state ① shown in Figure 5 ).

[0065] In Figure 5 , the arrow L indicates the flow of the brake fluid.

[0066] In addition, as can be seen from Figure 6 , the entry process of the piston 120 (from state ① to state ②) and the return process of the piston 120 (from state ② to state ③) can be seen. During the return process, the slope of the piston stroke changes greatly.

[0067] As described above, by temporarily forming a state where the first communication hole 160 and the discharge port 150 are in communication, the pressure in the pressure chamber 130 can be reduced to the atmospheric open state in a short time.

[0068] Please refer to Figure 1 and Figure 5 again. The hydraulic pressure generating device 100 may further include: a vehicle behavior stabilizer 192 for supporting the stabilization of vehicle behavior; and a wheel brake cylinder 194. The pressure chamber 130 is connected to the wheel brake cylinder 194 through the vehicle behavior stabilizer 192. The controller 180 is configured such that when the vehicle behavior stabilizer 192 operates, the piston 120 is moved to a position where the first communication hole 160 and the discharge port 150 are in a communicating state.

[0069] As described above, when the vehicle behavior stabilizer 192 operates, the first communication hole 160 and the discharge port 150 are in a communicating state, allowing more brake fluid (such as the arrow L in state ③ shown in Figure 5 ) than the initial state to flow to the side of the vehicle behavior stabilizer 192, so that the vehicle behavior stabilizer 192 operates smoothly.

[0070] Please refer to Figure 2 again. In the hydraulic pressure generating device 100 according to an embodiment of the present invention, the total flow rate of the brake fluid that can flow through the second communication hole 170 provided in each of the plurality of pistons 120 per unit time is the same.

[0071] As described above, the timing of applying pressure to each pressure chamber 130 can be matched, and the timing of applying braking can be matched.

[0072] In an embodiment of the hydraulic generation device 100 of the present invention, the master cylinder MS that generates braking hydraulic pressure when the driver steps on the brake pedal (braking operation) and the cylinder 110 are separately provided (as Figure 1 shown in Figure 2 ), convert the driver's braking operation into an electrical signal to operate the cylinder 110, and use the braking hydraulic pressure generated by this cylinder 110 to operate the wheel brake cylinder 194, thus forming a brake-by-wire (BBW) structure. Additionally, in other embodiments, the master cylinder MS and the cylinder 110 may also be directly connected (not shown), forming a direct-acting brake structure.

[0073] In summary, the hydraulic generation device of the embodiment of the present invention has at least the following technical effects:

[0074] In the initial state, the second communication hole is in communication with the drain port, maintaining an open-atmosphere state. Since the total flow rate of the brake fluid that can flow through the second communication hole per unit time is less than the total flow rate of the brake fluid that can flow through the first communication hole per unit time, less brake fluid flows out, the loss stroke can be shortened, and the hydraulic pressure can be more easily established.

[0075] By temporarily forming a state where the first communication hole is in communication with the drain port, the pressure in the pressure chamber can be reduced to the open-atmosphere state in a short time.

[0076] When the vehicle behavior stabilizer operates, the first communication hole and the drain port are in a communicating state, allowing more brake fluid to flow to the side of the vehicle behavior stabilizer than in the initial state, thereby enabling the vehicle behavior stabilizer to operate smoothly.

[0077] It is possible to match the timing of applying pressure to each pressure chamber and the timing of applying brakes.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic generating device, characterized in that, Comprising: A cylinder barrel; A plurality of pistons, linked to the brake pedal, and displaced within the cylinder barrel by a motor in association with the actuation of the brake pedal; A pressure chamber, communicating with a hollow portion formed in the piston and formed within the cylinder barrel, generating a hydraulic pressure corresponding to the displacement of the piston in the brake fluid; A reservoir, accumulating the brake fluid and communicating with the interior of the cylinder barrel via a drain port; A plurality of first communication holes, formed on the peripheral wall of the hollow portion, switching the communication state and non-communication state with the drain port by the displacement of the piston; and A second communication hole, formed on the peripheral wall of the hollow portion of the piston provided with the first communication hole, and the second communication hole is located at the rear side in the traveling direction of the piston of the first communication hole, the second communication hole switching the communication state and the non-communication state with the drain port; Wherein, The total flow rate of the brake fluid that can flow through the second communication hole per unit time is less than the total flow rate of the brake fluid that can flow through the first communication hole per unit time; In the initial state of the hydraulic pressure generating device, the first communication hole is in the non-communication state, and the second communication hole is in the communication state.

2. The hydraulic generating device according to claim 1, wherein Further comprising: A controller for controlling the driving amount of the motor, The controller is configured to: When the piston returns from the pressurized state to the initial state, after the piston moves to a position where the first communication hole and the drain port become in the communication state, return to the initial state.

3. The hydraulic generating device according to claim 2, wherein, Further comprising: A vehicle behavior stabilizer for supporting the stabilization of vehicle behavior; And A wheel brake cylinder, Wherein, the pressure chamber is connected to the wheel brake cylinder via the vehicle behavior stabilizer, The controller is configured to: When the vehicle behavior stabilizer operates, move the piston to a position where the first communication hole and the drain port become in the communication state.

4. The hydraulic pressure generating device according to claim 1, wherein The total flow rate of the brake fluid that can flow through the second communication hole provided in each of the plurality of pistons per unit time is the same.

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