A boosting structure for a brake valve

Abstract

The present invention provides a boosting structure of a brake valve, belonging to the field of hydraulic technology. It solves the problem that the existing brake pressure increase and large flow output cannot be taken into account at the same time. The boosting structure of the brake valve includes a valve body with a return oil circuit and a brake oil circuit, a main valve core is slidably connected in the valve body, a first oil chamber and a second oil chamber are formed between one end of the main valve core and the valve body, the first oil chamber is connected to the brake oil circuit, a first one-way component that can make the second oil chamber conduct to the brake oil circuit is provided in the valve body, a pressure relief chamber that is connected to both the second oil chamber and the return oil circuit is provided in the main valve core, a pressure relief valve core that can block the connection between the second oil chamber and the return oil circuit is slidably provided in the pressure relief chamber, the pressure relief chamber has an opening that is connected to the first oil chamber, and when the oil pressure of the first oil chamber increases and pushes the pressure relief valve core to slide, the second oil chamber is connected to the return oil circuit. The boosting structure of the brake valve has the advantages of increasing the output flow while increasing the brake pressure.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulics and relates to an assisting structure for a brake valve. Background Art

[0002] The function of a brake valve is a device for controlling the hydraulic braking of a vehicle. It includes a valve body having an inner cavity. A piston assembly is slidably connected in the valve body. The brake pedal is connected to one end of the piston assembly through a push rod. There is an oil cavity storing brake fluid between the piston assembly and the valve body. The valve body has a brake oil port for outputting brake fluid. When the driver steps on the brake pedal, the piston assembly is driven to move, the volume of the oil cavity decreases, the brake fluid is compressed, so that the brake fluid generates pressure, and the pressurized brake fluid flows to the brake through the brake oil port.

[0003] Engineering vehicles are heavy in self-weight and need to carry goods and drive in construction sites, mines or other rough areas, and the load may change frequently. This means that the braking of engineering vehicles requires greater braking pressure. The braking pressure is determined by the entire braking system, including the brake valve, brake fluid, brake pipelines, brake pads, brake discs / drums, etc. If starting from the brake valve, considering that the engineering vehicle requires a large flow rate of brake fluid for braking, the output flow rate of the brake valve needs to be increased. If the oil cavity volume is reduced to increase the brake fluid pressure, the output flow rate of the brake valve will be reduced, which cannot meet the large-flow braking requirements of engineering vehicles. Therefore, those skilled in the art will select a large-capacity brake valve, which has a larger oil cavity, and increase the acting force applied to the piston assembly, such as providing assistance for the movement of the piston assembly by means of oil pressure. For example, a fully hydraulic brake valve CN201620817367.7 disclosed in Chinese patent literature; or changing the existing pressurization method of brake fluid, pressurizing the brake fluid by a hydraulic pump, and guiding the brake fluid output by the hydraulic pump to the brake through the movement of the piston assembly of the brake valve. For example, a hydraulic brake valve CN200920119050.6 disclosed in Chinese patent literature. Summary of the Invention

[0004] The object of the present invention is to address the above problems existing in the prior art and propose an assisting structure for a brake valve, and the technical problem to be solved is how to increase the braking pressure while increasing the output flow rate.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] A boosting structure of a brake valve, comprising a valve body having an oil return circuit and a brake oil circuit. A main spool is slidably connected within the valve body. A first oil chamber and a second oil chamber are formed between one end of the main spool and the valve body. The first oil chamber is in communication with the brake oil circuit. A first one-way assembly capable of conducting the second oil chamber to the brake oil circuit is provided within the valve body. A pressure relief chamber communicating with both the second oil chamber and the oil return circuit is provided within the main spool. A pressure relief spool capable of blocking the communication between the second oil chamber and the oil return circuit is slidably disposed within the pressure relief chamber. The pressure relief chamber has an opening communicating with the first oil chamber. When the oil pressure in the first oil chamber increases and pushes the pressure relief spool to slide, the second oil chamber and the oil return circuit are in communication.

[0007] The oil return circuit of this application is in communication with the liquid storage tank of the prior art. Brake fluid is stored in both the first oil chamber and the second oil chamber of this application. When the driver steps on the brake pedal, the main spool moves to compress the second oil chamber. At this time, the pressure relief spool moves synchronously with the main spool, causing the brake fluid in the second oil chamber to generate pressure. The first oil chamber is in communication with the brake oil circuit. At this time, the pressure in the brake oil circuit is less than that in the second oil chamber. The first one-way assembly is opened under the oil pressure of the second oil chamber, and the oil in the second oil chamber supplies oil to the brake through the brake oil circuit. As the brake fluid in the second oil chamber flows to the brake through the brake oil circuit, the brake builds pressure. Initially, the pressure relief spool blocks the communication between the second oil chamber and the oil return circuit. When the oil pressure in the brake oil circuit exceeds the oil pressure in the second oil chamber, the first one-way assembly closes. Since the first oil chamber is in communication with the brake oil circuit and the opening of the pressure relief chamber is in communication with the first oil chamber, the oil pressure in the first oil chamber flows into and acts on the pressure relief spool through the opening of the pressure relief chamber. The pressure relief spool moves relative to the main spool under the action of the oil pressure in the first oil chamber, causing the second oil chamber to be in communication with the oil return circuit. The main spool moves further, and the brake fluid in the second oil chamber flows to the oil return circuit through the pressure relief chamber, that is, the second oil chamber is unloaded. The oil pressure in the first oil chamber further increases, causing the oil pressure of the oil flowing to the brake through the brake oil circuit to increase. Thus, while increasing the braking pressure, the output flow rate is also increased.

[0008] Furthermore, to achieve a large flow output of the brake valve in this application, instead of simply increasing the volume of the oil chamber for accommodating brake fluid within the brake valve, two oil chambers are provided. The pressure of the brake fluid is amplified step by step through the coordinated action of the two oil chambers, and the brake fluid is output through the brake oil circuit in two stages. In the first stage, the second oil chamber can quickly build pressure and output brake fluid under the push of the main spool to ensure the braking response speed of the brake valve. In the second stage, the first oil chamber outputs brake fluid with a greater pressure under the push of the main spool, thereby increasing the braking pressure while increasing the output flow rate.

[0009] In the boosting structure of a brake valve described above, the inner wall of the valve body has a ring-shaped and inwardly protruding contraction portion. The first oil chamber is located radially inside the contraction portion, and the second oil chamber is located axially outside the contraction portion. The main spool has a first compression portion that slides against the wall of the first oil chamber and a second compression portion that slides against the wall of the second oil chamber. The cross-sectional area of the second compression portion is 4 to 8 times that of the first compression portion. The first one-way assembly is arranged in the contraction portion. This structure makes the volume of the second oil chamber larger than that of the first oil chamber, and it can be set so that the second oil chamber can hold enough brake fluid to make the brake disc and brake pads fit. When the main spool moves, the second compression portion compresses the second oil chamber, and the second oil chamber supplies oil to the brake first. As the brake pressure increases, the second oil chamber unloads. According to the principle of fluid mechanics, the oil pressure P = the force F acting on the main spool divided by the piston acting area A. Since the cross-sectional area of the second compression portion is 4 to 8 times that of the first compression portion, the piston acting area is reduced, making the oil pressure output from the first oil chamber increase. When the brake disc and brake pads on the brake fit, the first oil chamber then outputs brake fluid to supply oil to the brake. In this way, both large displacement and high pressure can be ensured; the first one-way assembly is arranged inside the contraction portion to avoid the first one-way assembly occupying the space of the oil chamber.

[0010] In the boosting structure of a brake valve described above, a stepped hole is formed in the contraction portion. The large end of the stepped hole is communicated with the brake oil circuit, and the small end of the stepped hole is communicated with the second oil chamber. The first one-way assembly includes a steel ball located in the stepped hole. A first limiting member penetrating into the stepped hole is fixedly connected to the valve body. The steel ball can roll between the first limiting member and the stepped surface of the stepped hole. When the oil pressure in the second oil chamber is greater than that in the first oil chamber, the steel ball rolls towards the first limiting member, making the second oil chamber communicate with the first oil chamber through the stepped hole. The first limiting member prevents the steel ball from coming out of the stepped hole; when the oil pressure in the first oil chamber is greater than that in the second oil chamber, the steel ball rolls towards the stepped surface to block the second oil chamber, thereby realizing the one-way conduction function of the first one-way assembly.

[0011] In the boosting structure of a brake valve described above, the contraction portion has a ring-shaped guiding portion protruding axially along the main spool. The guiding portion is arranged along the inner circle of the contraction portion. The end of the main spool penetrates into the guiding portion to separate the first oil chamber and the second oil chamber. This structure makes the guiding portion located in the second oil chamber, increasing the volume of the first oil chamber, increasing the brake fluid that the first oil chamber can hold, and improving the oil pressure output by the brake valve.

[0012] In the boosting structure of a brake valve described above, a first return spring sleeved outside the guiding portion is arranged in the second oil chamber. One end of the first return spring abuts against the contracting portion, and the other end of the first return spring abuts against the main spool valve. The main spool valve has a limiting surface that can abut against the guiding portion. The guiding portion provides guidance for the movement of the first return spring, and the limiting surface defines the stroke of the main spool valve moving towards the first oil tank, so that the amount and pressure of the brake fluid output by the brake valve are determined.

[0013] In the boosting structure of a brake valve described above, the pressure relief chamber is arranged along the axial direction of the main spool valve, and the opening of the pressure relief chamber is located on the end face of the main spool valve. An oil inlet hole communicating the pressure relief chamber and the second oil chamber and an oil outlet hole communicating the pressure relief chamber and the oil return oil path are formed on the main spool valve. The oil inlet hole and the oil outlet hole are arranged at intervals along the length direction of the pressure relief chamber. The pressure relief spool valve blocks the orifice of the oil inlet hole, and an oil passing oil path capable of communicating the oil inlet hole and the oil outlet hole is arranged in the pressure relief spool valve. Arranging the opening of the pressure relief chamber on the end face of the main spool valve reduces the resistance of the oil in the first oil chamber entering the pressure relief chamber. Arranging the oil inlet hole and the oil outlet hole along the axial direction of the main spool valve realizes the on-off control of the oil inlet hole and the oil outlet hole through the pressure relief spool valve, and the oil inlet hole and the oil outlet hole are communicated by the oil passing oil path, improving the movement stability of the pressure relief spool valve.

[0014] In the boosting structure of a brake valve described above, the pressure relief chamber includes a sliding section in the shape of a circular hole and a connecting section. The aperture of the connecting section is larger than that of the sliding section. The orifice of the oil inlet hole is located on the sliding section, and the orifice of the oil outlet hole is located on the connecting section. The pressure relief spool valve is columnar and is slidably connected with the sliding section. The oil passing oil path has a first communication hole and a second communication hole on the outer wall of the pressure relief spool valve. The first communication hole can communicate with the oil inlet hole, and the second communication hole is located in the connecting section. This structure enables a gap between the pressure relief spool valve and the sliding section. When the pressure relief spool valve moves to make the first communication hole communicate with the oil inlet, the oil flowing in from the first communication hole can flow to the sliding section through the second communication hole without the second communication hole communicating with the oil outlet hole. This structure reduces the machining accuracy of the pressure relief spool valve.

[0015] In the boosting structure of a brake valve described above, an annular groove is formed on the outer wall of the pressure relief valve core. At least two of the above-mentioned first communication holes are formed at the bottom of the groove and are circumferentially spaced around the pressure relief valve core. A second limiting member located in the communication section is fixedly connected to the main valve core. A limiting retaining ring is positioned at the opening of the pressure relief cavity. The pressure relief valve core slides between the limiting retaining ring and the second limiting member. A second return spring is arranged in the communication section and elastically acts on one end of the pressure relief valve core, causing the other end of the pressure relief valve core to abut against the limiting retaining ring. When the pressure relief valve core abuts against the second limiting member, the first communication hole communicates with the oil inlet hole. The setting of the groove reduces the opening precision of the first communication. The pressure relief valve core slides between the limiting retaining ring and the second limiting member, making the sliding path of the pressure relief valve core determined, and improving the stability of the pressure relief valve core controlling the on-off of the second oil chamber and the oil return circuit.

[0016] In the boosting structure of a brake valve described above, a second one-way component is arranged in the main valve core. When the main valve core moves under the elastic force of the first return spring, the second one-way component can make the oil return circuit conduct to the second oil chamber. When braking ends and the main valve core moves back under the elastic force of the first return spring, the second one-way component opens, and the oil return circuit replenishes oil to the second oil chamber, preventing the second oil chamber from being sucked empty due to lack of brake fluid.

[0017] In the boosting structure of a brake valve described above, an oil replenishing circuit is formed on the main valve core. The second one-way component is located in the oil replenishing circuit. The oil replenishing circuit has a diversion hole communicating with the oil outlet hole and an oil replenishing hole communicating with the second oil chamber. The aperture of the oil replenishing hole is smaller than that of the diversion hole. The diversion hole utilizes the communication structure between the oil outlet hole and the oil return circuit. The oil outlet hole is used to discharge the brake fluid in the second oil chamber during braking, and the guiding hole replenishes oil to the second oil chamber after braking ends. Connecting the diversion hole with the oil outlet hole enables the oil lost in the second oil chamber during braking to be replenished again, reducing the flow path of the brake fluid, improving the timeliness of oil replenishment, and setting the aperture of the oil replenishing hole to be smaller than that of the diversion hole, enabling the oil output from the oil replenishing hole to assist in the resetting of the main valve core.

[0018] Compared with the prior art, the boosting structure of a brake valve provided by the present invention has the following advantages:

[0019] 1. This application adopts a double-chamber design, that is, two oil chambers for containing brake fluid are arranged between the valve body and the main spool. The two oil chambers respectively match the pressures required in different stages of the brake, and the volume of one oil chamber is larger than that of the other. When the main spool moves, first, the larger oil chamber delivers brake fluid to the brake to satisfy the contact between the brake pads and the brake disc in the brake. When the main spool continues to move, on the premise that the acting force driving the main spool to move remains unchanged, due to the increase in the area ratio between the smaller oil chamber and the main spool, the oil pressure output by the smaller oil chamber increases to satisfy the pressure required for the brake pads to clamp the brake disc, thereby increasing the braking pressure while increasing the output flow rate.

[0020] 2. On the basis of the double-chamber structure, during the braking process, the larger oil chamber is depressurized to reduce the moving resistance of the main spool, so that the acting force driving the main spool to move acts completely on the smaller oil chamber, further increasing the oil pressure that the smaller oil chamber can output. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of the brake valve in the initial state.

[0022] Figure 2 is Figure 1 a partial enlarged view of

[0023] Figure 3 is Figure 2 a partial enlarged view of the position A in

[0024] Figure 4 is a partial enlarged view of the brake valve in the braking state Figure 1 .

[0025] Figure 5 is a partial enlarged view of the brake valve in the braking state Figure 2 .

[0026] Figure 6 is Figure 5 a partial enlarged view of the position B in

[0027] In the figure, 1 is the valve body; 11 is the oil return circuit; 12 is the braking oil circuit; 13 is the contraction part; 131 is the guiding part; 14 is the stepped hole; 141 is the stepped surface; 2 is the main spool valve; 21 is the pressure relief cavity; 211 is the opening; 212 is the sliding section; 213 is the connecting section; 22 is the pressure relief spool valve; 221 is the oil passing circuit; 222 is the first connecting hole; 223 is the second connecting hole; 224 is the groove; 23 is the first compression part; 24 is the second compression part; 25 is the limiting surface; 26 is the oil inlet hole; 27 is the oil outlet hole; 28 is the oil replenishing circuit; 281 is the diversion hole; 282 is the oil replenishing hole; 3 is the first oil cavity; 4 is the second oil cavity; 5 is the first one-way component; 51 is the steel ball; 52 is the first limiting component; 6 is the first return spring; 7 is the second limiting component; 8 is the limiting retaining ring; 9 is the second return spring; 10 is the second one-way component; Br is the braking port; T is the oil return port. Detailed implementation mode

[0028] The following are specific embodiments of the present invention and in combination with the accompanying drawings, the technical solutions of the present invention are further described, but the present invention is not limited to these embodiments.

[0029] As Figure 1 and Figure 2 shown, the boosting structure of this brake valve includes a valve body 1 with an oil return circuit 11 and a braking oil circuit 12. A main spool valve 2 is slidably connected inside the valve body 1. There are a first oil cavity 3 and a second oil cavity 4 between one end of the main spool valve 2 and the valve body 1. The inner wall of the valve body 1 has an inwardly protruding and annular contraction part 13. The first oil cavity 3 is located radially inside the contraction part 13, and the second oil cavity 4 is located axially outside the contraction part 13. The first oil cavity 3 is communicated with the braking oil circuit 12. A first one-way component 5 that can conduct the second oil cavity 4 to the braking oil circuit 12 is provided inside the valve body 1. The main spool valve 2 has a pressure relief cavity 21 that communicates the second oil cavity 4 and the oil return circuit 11. A pressure relief spool valve 22 is slidably connected inside the pressure relief cavity 21. The pressure relief spool valve 22 controls the communication or disconnection between the second oil cavity 4 and the oil return circuit 11. The pressure relief cavity 21 has an opening 211 that communicates with the first oil cavity 3. When the pressure in the first oil cavity 3 is greater than the pressure in the second oil cavity 4, the pressure relief spool valve 22 slides to make the second oil cavity 4 and the oil return circuit 11 communicate.

[0030] The main spool valve 2 has a first compression part 23 that slides against the wall of the first oil chamber 3 and a second compression part 24 that slides against the wall of the second oil chamber 4. The cross-sectional area of the second compression part 24 is 4-8 times that of the first compression part 23. The contraction part 13 has a guiding part 131 that is annular and protrudes along the axial direction of the main spool valve 2. The guiding part 131 is arranged along the inner circle of the contraction part 13. The end of the main spool valve 2 passes through the guiding part 131 to separate the first oil chamber 3 and the second oil chamber 4. A first return spring 6 sleeved outside the guiding part 131 is arranged in the second oil chamber 4. One end of the first return spring 6 abuts against the contraction part 13, and the other end of the first return spring 6 abuts against the main spool valve 2. The main spool valve 2 has a limiting surface 25 that can abut against the guiding part 131.

[0031] The first one-way component 5 is arranged in the contraction part 13. A stepped hole 14 is formed in the contraction part 13. The large end of the stepped hole 14 is communicated with the braking oil circuit 12, and the small end of the stepped hole 14 is communicated with the second oil chamber 4. The first one-way component 5 includes a steel ball 51 located in the stepped hole 14. A first limiting member 52 that penetrates into the stepped hole 14 is fixedly connected to the valve body 1. The steel ball 51 can roll between the first limiting member 52 and the stepped surface 141 of the stepped hole 14.

[0032] The pressure relief cavity 21 is arranged along the axial direction of the main spool 2, and the opening 211 of the pressure relief cavity 21 is located on the end face of the main spool 2. An oil inlet hole 26 communicating the pressure relief cavity 21 and the second oil cavity 4 and an oil outlet hole 27 communicating the pressure relief cavity 21 and the oil return circuit 11 are formed on the main spool 2. The oil inlet hole 26 and the oil outlet hole 27 are arranged at intervals along the length direction of the pressure relief cavity 21. The pressure relief spool 22 plugs the orifice of the oil inlet hole 26, and an oil passage 221 capable of communicating the oil inlet hole 26 and the oil outlet hole 27 is provided in the pressure relief spool 22. The pressure relief cavity 21 includes a sliding section 212 in the shape of a circular hole and a connecting section 213. The aperture of the connecting section 213 is larger than that of the sliding section 212. The orifice of the oil inlet hole 26 is located on the sliding section 212, and the orifice of the oil outlet hole 27 is located on the connecting section 213. The pressure relief spool 22 is columnar and slidably connected to the sliding section 212. The oil passage 221 has a first communication hole 222 and a second communication hole 223 on the outer wall of the pressure relief spool 22. The first communication hole 222 can communicate with the oil inlet hole 26, and the second communication hole 223 is located in the connecting section 213. When the pressure relief spool 22 moves axially along the main spool 2 until the first communication hole 222 is aligned with the oil inlet hole 26, the first communication hole 222 communicates with the oil inlet hole 26. An annular groove 224 is formed on the outer wall of the pressure relief spool 22. At least two of the above-mentioned first communication holes 222 are formed at the bottom of the groove 224 at intervals along the circumferential direction of the pressure relief spool 22. A second limiting member 7 located in the connecting section 213 is fixedly connected to the main spool 2. A limiting retaining ring 8 is positioned at the opening 211 of the pressure relief cavity 21. The pressure relief spool 22 slides between the limiting retaining ring 8 and the second limiting member 7. A second return spring 9 is arranged in the connecting section 213 and elastically acts on one end of the pressure relief spool 22 to make the other end of the pressure relief spool 22 abut against the limiting retaining ring 8. When the pressure relief spool 22 abuts against the second limiting member 7, the first communication hole 222 communicates with the oil inlet hole 26.

[0033] The oil return circuit 11 has an oil return hole communicating with the second oil cavity 4. When the main spool 2 can be in the initial position under the elastic force of the first return spring 6, the second oil cavity 4 communicates with the oil return circuit 11 through the oil return hole. A second one-way assembly 10 is provided on the main spool 2, which can make the oil return circuit 11 conduct to the second oil cavity 4 when the main spool 2 moves under the elastic force of the first return spring 6. An oil replenishing circuit 28 is formed on the main spool 2. The second one-way assembly is located in the oil replenishing circuit 28. The oil replenishing circuit 28 has a diversion hole 281 communicating with the oil outlet hole 27 and an oil replenishing hole 282 communicating with the second oil cavity 4. The aperture of the oil replenishing hole 282 is smaller than that of the diversion hole 281.

[0034] As Figures 1 - 3 shown, when the main spool 2 is in the initial state, the second oil cavity 4 is directly communicated with the oil return port T of the oil return circuit 11, and the pressure relief spool 22 cuts off the communication between the second oil cavity 4 and the oil return circuit 11. As Figure 4As shown, when the driver steps on the brake pedal, the main spool 2 moves leftward, cutting off the connection between the second oil chamber 4 and the oil return port T. The main spool 2 continues to move leftward, compressing the brake fluid in the second oil chamber 4, causing the second oil chamber 4 to start building pressure. When the oil pressure in the second oil chamber 4 is greater than that in the brake oil circuit 12, at this time, the first oil chamber 3 is connected to the brake oil circuit 12. Therefore, the pressure in the first oil chamber 3 is also lower than that in the second oil chamber 4. The steel ball 51 abuts against the first limiting member 52 under the pressure of the second oil chamber 4. The oil fluid in the second oil chamber 4 flows into the brake oil circuit 12 through the stepped hole 14 and outputs the pressurized brake fluid to the brake through the brake port Br. The pressure of the brake gradually increases as the brake fluid flows in. The oil pressure in the brake oil circuit 12 is basically equivalent to that of the brake. When the oil pressure in the brake oil circuit 12 is greater than that in the second oil chamber 4, the steel ball 51 abuts against the stepped surface 141 under the pressure of the brake oil circuit 12, disconnecting the connection between the second oil chamber 4 and the first oil chamber 3. At this time, the oil pressure in the first oil chamber 3 is also greater than that in the second oil chamber 4, as Figure 5 and Figure 6 shown. The brake fluid in the first oil chamber 3 will enter the pressure relief chamber 21, pushing the pressure relief spool 22 to move rightward relative to the main spool 2 and abut against the second limiting member 7, making the notch of the groove 224 face the orifice of the oil inlet hole 26, connecting the oil inlet hole 26 and the first communication hole 222, so that the brake fluid in the second oil chamber 4 flows out through the second communication hole 223 and then flows to the oil return oil circuit 11 through the oil outlet hole 27, relieving the pressure of the second oil chamber 4. The leftward movement of the main spool 2 will compress the first oil chamber 3, and the acting force applied to the main spool 2 acts on the first oil chamber 3. Since the cross-sectional area of the second compression part 24 is 4 - 8 times that of the first compression part 23, the compression of the first oil chamber 3 will output an oil pressure greater than that of the second oil chamber 4 to assist the final stage of braking, and the brake pads clamp the brake disc, thus completing the vehicle braking. After braking is completed, the driver releases the brake pedal, and the main spool 2 moves rightward under the elastic force of the first return spring 6. The oil fluid of the brake returns to the brake valve through the opening 211 of the brake oil circuit 12. During the return movement of the main spool 2, the second one-way component opens, enabling the oil fluid in the oil return oil circuit 11 to enter the second oil chamber 4 through the oil replenishing oil circuit 28 to prevent the second oil chamber 4 from being sucked empty. The pressure relief spool 22 moves leftward under the elastic force of the second return spring 9, and the pressure relief spool 22 abuts against the limit retaining ring 8 again, cutting off the connection between the second oil chamber 4 and the pressure relief chamber 21. When the brake valve returns to the initial state, the second one-way component closes, and the second oil chamber 4 is reconnected to the oil return oil circuit 11. At this time, the oil return port T can be used as the oil replenishing port for the second oil chamber 4, that is, the brake fluid can be replenished to the second oil chamber 4 through the oil return port T.

[0035] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains may make various modifications or supplements to the described specific embodiments or use similar means for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0036] Although terms such as valve body 1, oil return oil path 11, brake oil path 12, contraction part 13, guiding part 131, stepped hole 14, stepped surface 141, main spool valve 2, pressure relief cavity 21, opening 211, sliding section 212, communicating section 213, pressure relief spool valve 22, oil passing oil path 221, first communication hole 222, second communication hole 223, groove 224, first compression part 23, second compression part 24, limiting surface 25, oil inlet hole 26, oil outlet hole 27, oil replenishing oil path 28, diversion hole 281, oil replenishing hole 282, first oil cavity 3, second oil cavity 4, first one-way assembly 5, steel ball 51, first limiting member 52, first return spring 6, second limiting member 7, limiting retaining ring 8, second return spring 9, second one-way assembly 10, brake port Br, oil return port T, etc. are used more frequently herein, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A brake valve booster structure, comprising a valve body (1) having an oil return oil circuit (11) and a brake oil circuit (12), wherein a main valve core (2) is slidably connected to the valve body (1), characterized in that: A first oil chamber (3) and a second oil chamber (4) are formed between one end of the main valve core (2) and the valve body (1); the first oil chamber (3) is connected to the brake oil circuit (12); a first one-way component (5) is provided in the valve body (1) to enable the second oil chamber (4) to be connected to the brake oil circuit (12); a pressure relief chamber (21) is provided in the main valve core (2) to be connected to both the second oil chamber (4) and the return oil circuit (11); a pressure relief valve core (22) is slidably provided in the pressure relief chamber (21) to block the connection between the second oil chamber (4) and the return oil circuit (11); the pressure relief chamber (21) has an opening (211) connected to the first oil chamber (3); when the oil pressure in the first oil chamber (3) increases, the pressure relief chamber (21) is opened. When the large and pushing pressure relief valve core (22) slides, the second oil chamber (4) and the oil return oil path (11) are connected, the inner wall of the valve body (1) has a contraction portion (13) protruding inward and in an annular shape, the first oil chamber (3) is located radially inside the contraction portion (13), the second oil chamber (4) is located axially outside the contraction portion (13), the main valve core (2) has a first compression portion (23) sliding against the cavity wall of the first oil chamber (3) and a second compression portion (24) sliding against the cavity wall of the second oil chamber (4), the cross-sectional area of ​​the second compression portion (24) is 4-8 times the cross-sectional area of ​​the first compression portion (23), and the first one-way component (5) is arranged in the contraction portion (13).

2. The booster structure of the brake valve according to claim 1, characterized in that: The contraction portion (13) is provided with a step hole (14), the large end of the step hole (14) is connected to the brake oil circuit (12), and the small end of the step hole (14) is connected to the second oil chamber (4), the first one-way component (5) includes a steel ball (51) located in the step hole (14), and the valve body (1) is fixedly connected with a first stopper (52) that penetrates into the step hole (14), and the steel ball (51) can roll between the first stopper (52) and the step surface (141) of the step hole (14).

3. The booster structure of the brake valve according to claim 1 or 2, characterized in that: The contraction portion (13) has a guide portion (131) which is annular and protrudes along the axial direction of the main valve core (2); the guide portion (131) is arranged along the inner ring of the contraction portion (13); the end of the main valve core (2) is inserted into the guide portion (131) to separate the first oil chamber (3) from the second oil chamber (4).

4. The booster structure of the brake valve according to claim 3, characterized in that: A first return spring (6) sleeved outside the guide portion (131) is provided in the second oil chamber (4); one end of the first return spring (6) abuts against the contraction portion (13); the other end of the first return spring (6) abuts against the main valve core (2); and the main valve core (2) has a limit surface (25) capable of abutting against the guide portion (131).

5. The booster structure of the brake valve according to claim 4, characterized in that: The pressure relief chamber (21) is arranged along the axial direction of the main valve core (2), and the opening (211) of the pressure relief chamber (21) is located on the end surface of the main valve core (2). The main valve core (2) is provided with an oil inlet hole (26) connecting the pressure relief chamber (21) and the second oil chamber (4), and an oil outlet hole (27) connecting the pressure relief chamber (21) and the oil return oil path (11). The oil inlet hole (26) and the oil outlet hole (27) are arranged at intervals along the length direction of the pressure relief chamber (21). The pressure relief valve core (22) blocks the opening of the oil inlet hole (26), and the pressure relief valve core (22) has an oil passage (221) that can connect the oil inlet hole (26) and the oil outlet hole (27).

6. The booster structure of the brake valve according to claim 5, characterized in that: The pressure relief chamber (21) comprises a circular hole-shaped sliding section (212) and a connecting section (213); the aperture of the connecting section (213) is larger than the aperture of the sliding section (212); the orifice of the oil inlet hole (26) is located on the sliding section (212); the orifice of the oil outlet hole (27) is located on the connecting section (213); the pressure relief valve core (22) is columnar and slidably connected to the sliding section (212); the oil passage (221) comprises a first connecting hole (222) and a second connecting hole (223) located on the outer wall of the pressure relief valve core (22); the first connecting hole (222) can be connected to the oil inlet hole (26); and the second connecting hole (223) is located in the connecting section (213).

7. The booster structure of the brake valve according to claim 6, characterized in that: The outer wall of the pressure relief valve core (22) is provided with an annular groove (224), and the bottom of the groove (224) is provided with at least two of the above-mentioned first communication holes (222) arranged at intervals around the pressure relief valve core (22) in the circumferential direction. The main valve core (2) is fixedly connected with a second limiter (7) located in the communication section (213). A limiter retaining ring (8) is positioned at the opening (211) of the pressure relief chamber (21). The pressure relief valve core (22) slides between the limiter retaining ring (8) and the second limiter (7). A second return spring (9) is provided in the communication section (213) and elastically acts on one end of the pressure relief valve core (22) and causes the other end of the pressure relief valve core (22) to abut against the limiter retaining ring (8). When the pressure relief valve core (22) abuts against the second limiter (7), the first communication hole (222) is communicated with the oil inlet hole (26).

8. The booster structure of the brake valve according to claim 7, characterized in that: A second one-way component (10) is provided in the main valve core (2). When the main valve core (2) moves under the elastic force of the first return spring (6), the second one-way component (10) can connect the return oil path (11) to the second oil chamber (4).

9. The booster structure of the brake valve according to claim 8, characterized in that: An oil replenishment circuit (28) is provided on the main valve core (2), the second single component is located in the oil replenishment circuit (28), the oil replenishment circuit (28) has a guide hole (281) connected to the oil outlet hole (27) and an oil replenishment hole (282) connected to the second oil chamber (4), and the diameter of the oil replenishment hole (282) is smaller than the diameter of the guide hole (281).

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