Tandem type drive-by-wire piston assembly

Abstract

The utility model provides a tandem type drive-by-wire piston assembly which comprises a piston cavity shell, a plug is installed at the bottom of the piston cavity shell, the side, away from the piston cavity shell, of the plug is installed on a manual piston, the side, away from the plug, of the manual piston is installed on a drive-by-wire piston, and the drive-by-wire piston is installed on the drive-by-wire piston. A valve element push rod is installed on the top of the piston cavity shell. The manual piston and the drive-by-wire piston form an independent closed piston chamber by adopting a star-shaped sealing ring, and the frictional resistance of piston movement can be effectively reduced due to small frictional resistance of the star-shaped sealing ring.

Description

Technical Field

[0001] This utility model relates to an electro-hydraulic braking system, and more particularly to a tandem-type drive-by-wire piston assembly. Background Technology

[0002] In current electro-hydraulic braking systems, piston assemblies are widely used, and they are basically in parallel configuration, as follows: Figure 1 As shown, during normal braking, the high-pressure valve core can be opened by manually piloting the piston, resulting in deceleration and braking. In emergency situations, to maximize the safety of the driver and passengers, electronic sensing equipment is used to autonomously identify sudden situations during driving. When the driver has not yet had time to brake, the drive-by-wire system automatically opens the high-pressure brake fluid and pushes the drive-by-wire piston forward to open the high-pressure valve core, thus performing autonomous deceleration and braking in place of the driver.

[0003] In this process, the drive-by-wire piston and the manual piston are connected in parallel, which is complex and has high manufacturing costs. The drive-by-wire piston is inserted into the manual piston. Due to the large number of seals during the process, the frictional resistance during movement is large, which will affect the normal return of the piston. When there is pressure inside the manual piston, the drive-by-wire piston cannot return in time, which can easily cause the brake to fail to be released, thus affecting the safety of braking.

[0004] Typically, the diameter of a drive-by-wire piston is smaller than that of a manual piston, resulting in a much smaller assist ratio for the drive-by-wire piston compared to the manual piston. During drive-by braking, a higher hydraulic pressure is required to achieve the same braking effect as manual braking, which affects the wheel-side pressure build-up speed. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of the prior art by providing a series-connected drive-by-wire piston assembly. This assembly employs a structure in which a manual piston and a drive-by-wire piston are arranged in series. During manual braking, the manual piston pushes the drive-by-wire piston to achieve braking and deceleration. During drive-by braking, the manual piston remains stationary, while the drive-by-wire piston moves under the action of high-pressure hydraulic fluid, pushing open the valve core to produce a braking and deceleration effect. The structure is novel and easier to assemble.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This utility model provides a series-type wire-controlled piston assembly, including a piston chamber housing, a plug installed at the bottom of the piston chamber housing, a manual piston installed on the side of the plug away from the piston chamber housing, a wire-controlled piston installed on the side of the manual piston away from the plug, and a valve core push rod installed at the top of the piston chamber housing.

[0008] Furthermore, the plug is equipped with an O-ring.

[0009] Furthermore, a wire retaining ring is installed at the contact point between the plug and the piston chamber housing.

[0010] Furthermore, both the manual piston and the wire-controlled piston are fitted with star-shaped sealing rings.

[0011] Furthermore, a human-operated piston return spring is installed between the human-operated piston and the wire-controlled piston.

[0012] Furthermore, a return spring for the wire-controlled piston is installed between the wire-controlled piston and the piston chamber housing.

[0013] Furthermore, the space between the wire-controlled piston and the valve core push rod forms a third chamber, which is connected to the oil return port.

[0014] Furthermore, the space between the wire-controlled piston and the manual piston forms a second chamber, which is connected to the wire-controlled brake inlet.

[0015] Furthermore, the space between the manual piston and the plug forms a first chamber, which is connected to the manual brake oil inlet.

[0016] Furthermore, the diameter of the wire-controlled piston is the same as the diameter of the manual piston.

[0017] The beneficial effects of this utility model are as follows: the manual piston and the wire-controlled piston are composed of independent sealed piston chambers with star-shaped sealing rings. Because the star-shaped sealing rings have low frictional resistance, they can effectively reduce the frictional resistance of piston movement.

[0018] Both pistons are equipped with piston return springs, which are used to return the pistons to their original positions when the braking pressure is released. The return spring force of the manual piston is greater than that of the return spring force of the wire-controlled piston, ensuring that the manual piston can return to its original position in a timely manner when the wire-controlled piston returns to its original position.

[0019] The wire-controlled piston has the same diameter as the manual piston, and the power assist ratio of manual and wire-controlled braking is the same. Under the same conditions as the original structure, the pressure in the wire-controlled piston chamber is lower than before, but it can still achieve the same wheel-side pressure effect, reducing the consumption of high-pressure discharge and improving the pressure build-up time. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a prior art structure for a series-type drive-by-wire piston assembly;

[0021] Figure 2 This is a schematic diagram of a tandem-type drive-by-wire piston assembly. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0023] Please see Figure 2 A series-connected wire-controlled piston assembly includes a piston chamber housing 1, a plug 5 installed at the bottom of the piston chamber housing 1, a manual piston 9 installed on the side of the plug 5 away from the piston chamber housing 1, a wire-controlled piston 10 installed on the side of the manual piston 9 away from the plug 5, and a valve core push rod 2 installed at the top of the piston chamber housing 1.

[0024] The plug 5 is equipped with an O-ring rubber ring 7.

[0025] A wire retaining ring 6 is installed at the contact point between the plug 5 and the piston chamber housing 1.

[0026] Both the manual piston 9 and the wire-controlled piston 10 are fitted with star-shaped sealing rings 8.

[0027] A human-operated piston return spring 4 is installed between the human-operated piston 9 and the wire-controlled piston 10.

[0028] A wire-controlled piston return spring 3 is installed between the wire-controlled piston 10 and the piston chamber housing 1.

[0029] The space between the wire-controlled piston 10 and the valve core push rod 2 forms a third chamber 103, which is connected to the oil return port 201.

[0030] The space between the wire-controlled piston 10 and the manual piston 9 forms a second chamber 102, which is connected to the wire-controlled brake oil inlet 202.

[0031] The space between the manual piston 9 and the plug 5 forms a first chamber 101, which is connected to the manual brake oil inlet 203.

[0032] The diameter of the wire-controlled piston 10 is the same as the diameter of the manual piston 9.

[0033] The working principle of a series-type wire-controlled piston assembly is as follows: two star-shaped sealing rings 8 divide the piston chamber housing 1 into three chambers, namely the first chamber 101, the second chamber 102 and the third chamber 103;

[0034] First, the wire-controlled piston return spring 3 is installed into the piston chamber housing 1, and then the wire-controlled piston 10 equipped with the star-shaped sealing ring 8 is installed, forming the third chamber 103. The manual piston return spring 4 is placed into the tail groove of the wire-controlled piston 10, and then the manual piston 9 equipped with the star-shaped sealing ring 8 is installed, forming the second chamber 102 and the entire piston assembly.

[0035] The plug 5 with the O-ring 7 is inserted into the piston hole of the piston chamber housing 1 and limited by the wire retaining ring 6 to form the first chamber 101 and the sealed area of ​​the entire piston.

[0036] When the manual piston 9 is used for braking, the foot pedal is pressed, and the brake master cylinder pumps out high-pressure oil. The high-pressure oil enters from the manual brake inlet 203 and pushes the manual piston 9 toward the valve core push rod 2. The manual piston 9 overcomes the resistance of the manual piston return spring 4, the wire-controlled piston return spring 3 and the two star-shaped seals 8, and contacts and pushes the wire-controlled piston 10, so that the wire-controlled piston 10 pushes the valve core push rod 2 to move and outputs thrust to realize the braking function.

[0037] At this time, the star-shaped sealing ring 8 and the O-ring rubber ring 7 form a sealed area of ​​the manual piston 9, which converts the oil into thrust. When the brake is released, the wire-controlled piston 10 first returns to the initial position under the action of the wire-controlled piston return spring 3. Then, the manual piston 9 returns to the initial position under the combined action of the manual piston return spring 4 and the wire-controlled piston return spring 3. The liquid in the valve core push rod 2 returns to the oil reservoir through the third chamber 103.

[0038] When braking is applied using the wire-controlled piston 10, the manual piston 9 remains stationary. The high-pressure hydraulic fluid drives the wire-controlled piston 10 to move. The wire-controlled piston 10 overcomes the resistance of the wire-controlled piston return spring 3, causing the top of the wire-controlled piston 10 to push the valve core push rod 2 to move and output thrust, thus achieving the braking function.

[0039] At this time, the sealed area of ​​the third chamber 103 converts the oil into thrust. When the brake is released, the wire-controlled piston 10 returns to the initial position under the action of the wire-controlled piston return spring 3, and the liquid in the valve core push rod 2 returns to the oil reservoir through the return port 201.

[0040] When the preload of the wire-controlled piston return spring 3 is greater than the preload of the manual piston return spring 4, it ensures that all pistons in series can return to their normal positions.

[0041] The embodiments described above merely illustrate the implementation of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be defined by the appended claims.

Claims

1. A tandem-type drive-by-wire piston assembly, characterized in that: The piston chamber housing (1) includes a plug (5) installed at the bottom of the piston chamber housing (1), and the side of the plug (5) that is away from the piston chamber housing (1) is installed with a manual piston (9). The side of the manual piston (9) that is away from the plug (5) is installed with a wire-controlled piston (10). A valve core push rod (2) is installed at the top of the piston chamber housing (1).

2. The tandem-type drive-by-wire piston assembly according to claim 1, characterized in that: The plug (5) is fitted with an O-ring (7).

3. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: A wire retaining ring (6) is installed at the contact point between the plug (5) and the piston chamber housing (1).

4. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: Both the manual piston (9) and the wire-controlled piston (10) are fitted with star-shaped sealing rings (8).

5. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: A human piston return spring (4) is installed between the human piston (9) and the wire-controlled piston (10).

6. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: A return spring (3) for the wire-controlled piston is installed between the wire-controlled piston (10) and the piston chamber housing (1).

7. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: The space between the wire-controlled piston (10) and the valve core push rod (2) forms a third chamber (103), which is connected to the oil return port (201).

8. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: The space between the wire-controlled piston (10) and the manual piston (9) forms a second chamber (102), which is connected to the wire-controlled brake inlet (202).

9. A series-connected drive-by-wire piston assembly according to claim 1, characterized in that: The space between the manual piston (9) and the plug (5) forms a first chamber (101), which is connected to the manual brake oil inlet (203).

10. A tandem-type drive-by-wire piston assembly according to claim 1, characterized in that: The diameter of the wire-controlled piston (10) is the same as the diameter of the manual piston (9).

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