A brake valve

Abstract

The present invention provides a brake valve, belonging to the technical field of hydraulics. It solves the problem of the response lag of the existing brake valve. This brake valve includes a valve body and a push rod. 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 communicated with the brake oil circuit. A first one-way component capable of conducting the second oil chamber to the brake oil circuit is provided in the valve body. A pressure relief chamber communicated with both the second oil chamber and the oil return circuit is provided in the main spool. A pressure relief spool capable of blocking the communication between the second oil chamber and the oil return circuit is slidably arranged in the pressure relief chamber. The pressure relief chamber has an opening communicated with the first oil chamber. An installation hole communicated with both the oil inlet circuit and the oil return circuit is further provided in the main spool. An auxiliary spool capable of blocking the communication between the oil inlet circuit and the oil return circuit is slidably arranged in the installation hole. A pressure chamber is formed between one end of the auxiliary spool and the main spool. This end is connected to the push rod. The pressure chamber is communicated with the oil return circuit through the auxiliary spool. This brake valve has the advantages of improving the response timeliness and the braking effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulics and relates to 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 have a heavy self-weight and need to carry goods and drive on construction sites, mines or other rough areas, and the load may change frequently. This means that the braking of engineering vehicles requires a 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 the large flow rate of brake fluid required for the braking of engineering vehicles, 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, unable to meet the large-flow braking requirements of engineering vehicles. Therefore, those skilled in the art will select a brake valve with a large capacity. The brake valve with a large capacity has a larger oil cavity and increases 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 pressurizing 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.

[0004] Moreover, the movement of the piston assembly in the initial stage is driven by the acting force manually applied on the brake pedal, and the acting force direction is easily deflected when acting on the piston assembly through the push rod, thereby affecting the movement stability of the piston assembly. To improve the movement stability of the piston assembly, those skilled in the art easily think of setting a spring assembly between the push rod and the piston assembly, so that the acting force transmitted by the push rod acts on the piston assembly through the spring assembly. For example, a hydraulic brake valve for construction machinery vehicles CN202221738475.7 is disclosed in Chinese patent literature. Summary of the Invention

[0005] The object of the present invention is to address the above problems existing in the prior art by providing a brake valve, and the technical problem to be solved is how to improve the response timeliness while ensuring the braking effect.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A brake valve includes a valve body and a push rod. The valve body has an oil inlet circuit, an oil return circuit, and a brake oil circuit. A main spool is slidably connected within the valve body. It is characterized in that a first oil chamber is formed between one end of the main spool and the valve body, and the first oil chamber is in communication with the brake oil circuit. The main spool further has a mounting hole that is in communication with both the oil inlet circuit and the oil return circuit. An auxiliary spool that blocks the communication between the oil inlet circuit and the oil return circuit is slidably disposed within the mounting hole. A pressure chamber is formed between one end of the auxiliary spool and the main spool, and this end is connected to the push rod. The pressure chamber is in communication with the oil return circuit through the auxiliary spool. When the push rod drives the auxiliary spool to move, the pressure chamber is in communication with the oil inlet circuit through the auxiliary spool.

[0008] When the vehicle brakes, the driver steps on the brake pedal, and the push rod drives the auxiliary spool to move relative to the main spool, triggering the operation of the brake valve. The specific working process is as follows: First, the auxiliary spool cuts off the communication between the pressure chamber and the oil return circuit and connects the pressure chamber to the oil inlet circuit, so that the hydraulic oil in the oil inlet circuit enters the pressure chamber and acts on one end of the main spool, that is, the main spool is driven to move by means of the oil pressure. At this time, the main spool drives the pressure relief spool to move synchronously, compressing the first oil chamber, so that the first oil chamber delivers brake fluid to the brake through the brake oil circuit. It can be seen that in this application, the structure of driving the main spool to move by manually applying a force is cancelled, but the brake fluid entering the valve body acts on one end of the main spool to drive the main spool to move, improving the response speed of the brake valve after the driver steps on the brake pedal and ensuring the oil pressure output by the brake valve. Further, based on the structure of the main spool controlling the on-off of the oil circuit, the brake fluid is introduced into the interior of the main spool, that is, within the mounting hole. The auxiliary spool is slidably disposed within the mounting hole, so that the pressure chamber formed at one end of the main spool controls the inflow or outflow of the brake fluid into or out of the pressure chamber by driving the auxiliary spool to move, thereby realizing the control of the movement of the main spool.

[0009] A second oil chamber is also formed between the main spool valve and the valve body. Both the second oil chamber and the first oil chamber are located at one end of the main spool valve. A first one-way component capable of conducting the second oil chamber to the brake oil circuit is provided in the valve body. A pressure relief chamber communicating with both the second oil chamber and the oil return circuit is further provided in the main spool valve. A pressure relief spool capable of blocking the communication between the second oil chamber and the oil return circuit is slidably arranged in 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 communicated. During braking, the main spool valve moves to first compress the second oil chamber, so that the brake fluid in the second oil chamber generates pressure. The first oil chamber is communicated 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 component is opened under the action of the oil pressure in the second oil chamber. 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 component closes. Because the first oil chamber is communicated with the brake oil circuit and the opening of the pressure relief chamber is communicated 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. At this time, the pressure relief spool moves relative to the main spool valve under the action of the oil pressure in the first oil chamber, so that the second oil chamber is communicated with the oil return circuit. The main spool valve 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 brake fluid pressure in the first oil chamber further increases, so that the oil pressure of the oil flowing to the brake through the brake oil circuit increases. Thereby, while increasing the braking pressure, the output flow rate is increased. Further, the present application does not simply increase the volume of the oil chamber for accommodating the brake fluid in the brake valve, but two oil chambers are provided. The pressure of the brake fluid is amplified in stages through the cooperation 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 the brake fluid under the push of the main spool valve, so that the brake pads are abutted against the brake disc to ensure the braking response speed of the brake valve. In the second stage, the first oil chamber outputs the brake fluid with a greater pressure under the push of the main spool valve, thereby improving the braking effect while improving the response timeliness.

[0010] In the above-mentioned brake valve, the oil return oil path is located between the brake oil path and the oil inlet oil path, and the oil return oil path has a first oil return hole and a second oil return hole arranged at intervals along the axial direction of the main valve core. The main valve core has a second compression part which is columnar and slides against the wall of the second oil cavity. An annular first communication groove is formed in the upper part of the second compression part. The second oil cavity is communicated with the first oil return hole through the first communication groove. A first return spring is sleeved on the main valve core and located in the second oil cavity. The first return spring acts elastically on the second compression part. The second oil cavity can be communicated with the second oil return hole. During braking, when the second oil cavity is depressurized, the brake fluid flowing out of the second oil cavity flows to the oil return oil path through the first communication groove, so that part of the oil can be stored in the first communication groove. When braking ends, the main valve core moves back under the elastic force of the first return spring. The first communication groove can quickly replenish oil to the second oil cavity to avoid the second oil cavity being sucked empty and ensure the movement stability of the main valve core. When the main valve core moves back to the initial position, the second oil cavity is communicated with the second oil return hole, and the oil return oil path can replenish the oil required for the next braking to the second oil cavity to ensure the large-flow output of the second oil cavity.

[0011] In the above-mentioned brake valve, an assembly hole is formed in the main valve core and penetrates from one end to the other end. The brake valve further includes a second limiting member which is threadedly connected to the assembly hole and divides the assembly hole into the above-mentioned installation hole and the pressure relief cavity. This structure changes the oil path communication structure arranged on the valve body in the prior art to be arranged in the assembly hole of the main valve core. On the premise that the volume of the valve body remains unchanged, the cross-sectional area of the main valve core can be set larger, further increasing the area ratio between the first oil cavity and the main valve core, improving the braking force output by the first oil cavity. The assembly hole separates the installation hole and the pressure relief cavity through the second limiting member, so that the setting of the oil path is based on the main valve core.

[0012] In the above-mentioned brake valve, the second limiting member further has a head abutting against the bottom of the installation hole and a rod portion threadedly connected to the pressure relief cavity. The rod portion is stepped. The head and the rod portion are of an integral structure, and a first sealing ring is arranged between the rod portion and the wall of the pressure relief cavity. The head abuts against the first sealing ring, and a third return spring is sleeved outside the head. One end of the third return spring abuts against the bottom of the installation hole, and the other end of the third return spring abuts against the end of the auxiliary valve core. The head abuts against the bottom of the installation hole, so that the penetration depth of the rod portion in the communication section is determined. The first sealing ring improves the sealing performance between the communication section and the installation hole. The head plays a role in limiting the position of the third return spring to avoid the position deviation of the third return spring, so that the elastic force of the third return member acts stably on the end of the auxiliary valve core and improves the position stability of the auxiliary valve core.

[0013] In the above-mentioned brake valve, a second annular connecting groove is opened on the second compression part, and the second connecting groove is connected to the oil inlet circuit. The mounting hole includes a flared section and a straight hole section in the shape of a circular hole. The auxiliary valve core is columnar and is slidably connected to the straight hole section. The wall surface of the straight hole section is provided with an inflow hole and an outflow hole arranged along the axial direction of the main valve core. The outflow hole is connected to the first connecting groove, and the inflow hole is connected to the second connecting groove. The brake valve also includes a valve sleeve slidably connected to the valve body, and the pressure chamber is located between the wall surface of the flared section and the auxiliary valve core. One end of the valve sleeve is fixedly connected to the push rod, and the other end of the valve sleeve is connected to the auxiliary valve core. The second connecting channel provides assistance for the inflow and outflow of brake fluid, thereby increasing the speed at which the brake fluid enters or flows out of the pressure chamber; the inflow hole and the outflow hole are arranged at intervals along the axial direction of the connecting section, so that the inflow hole and the outflow hole are located on the moving path of the auxiliary valve core, and the valve sleeve is extended into the expansion section to shorten the setting length of the auxiliary valve core and improve the movement stability of the auxiliary valve core. The expansion section provides space for the setting of the pressure chamber, and this structure increases the effective area of ​​one end of the main valve core.

[0014] In the above brake valve, the aperture of the flared section gradually decreases from the end face of the main valve core toward the straight hole section, and a second limit retaining ring is fixedly connected to the wall surface of the small end of the flared section, the valve sleeve extends into the flared section, and the valve sleeve can abut against the first limit retaining ring, and the auxiliary valve core abuts against the second limit retaining ring under the elastic force of the third reset spring. The limit retaining ring has a limiting effect on the initial position of the auxiliary valve core on the one hand, and on the other hand limits the maximum movement stroke of the valve sleeve moving toward the main valve core installation hole to avoid interference between the main valve core and the valve sleeve.

[0015] In the above brake valve, one end of the auxiliary valve core extends out of the second limit retaining ring and is clamped with the valve sleeve, and the auxiliary valve core has a through hole extending from one end to the other end, and the pressure chamber is connected with the inflow hole or the outflow hole through the through hole. The valve sleeve and the auxiliary valve core are linked by the clamping structure, and the brake fluid enters the pressure chamber or flows out of the pressure chamber through the inside of the auxiliary valve core, which avoids the impact of the brake fluid on the auxiliary valve core during the flow process to the greatest extent, and increases the contact area between the auxiliary valve core and the mounting hole.

[0016] In the above-mentioned brake valve, the inner wall of the valve body has a constriction that protrudes inward and is annular. The first oil chamber is located radially inside the constriction, and the second oil chamber is located axially outside the constriction. The main spool also has a first compression part that is columnar and slides against the wall of the first oil chamber. The cross-sectional area of the second compression part is 4 to 8 times that of the first compression part. The first one-way assembly is arranged in the constriction. This structure makes the volume of the second oil chamber larger than that of the first oil chamber. The brake fluid contained in the second oil chamber is sufficient to make the brake disc and the brake pads fit together. When the main spool moves, the second compression part compresses the second oil chamber, and the second oil chamber supplies oil to the brake first. As the pressure of the brake 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 area A. Since the cross-sectional area of the second compression part is 4 to 8 times that of the first compression part, the piston area is reduced, making the oil pressure output by the first oil chamber increase. When the brake disc and the brake pads on the brake fit together, the first oil chamber 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 in the constriction to prevent the first one-way assembly from occupying the space of the oil chamber.

[0017] In the above-mentioned brake valve, the opening of the pressure relief chamber is located on the end face of the main spool. A first limit retaining ring is positioned at the opening of the pressure relief chamber. 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. One end of the connecting section is connected to the sliding section, and the other end of the connecting section has a thread. The rod part is threadedly connected to the connecting section. A second return spring that elastically acts on one end of the pressure relief spool and makes the other end of the pressure relief spool abut against the first limit retaining ring is sleeved on the rod part. An oil passage is provided in the pressure relief spool. When the pressure relief spool abuts against the end face of the rod part, the second oil chamber is communicated with the oil return passage through the pressure relief chamber. Setting the opening of the pressure relief chamber on the end face of the main spool reduces the resistance of the oil in the first oil chamber entering the pressure relief chamber. The aperture of the connecting section is larger than that of the sliding section. The first limit retaining ring prevents the pressure relief spool from coming out of the opening of the pressure relief chamber. The rod part of the second limiting member passes through the connecting section. On the one hand, the rod part provides support and guidance for the second return spring. On the other hand, the rod part defines the maximum moving stroke of the pressure relief spool relative to the main spool under the action of hydraulic pressure, ensuring the connection stability between the second oil chamber and the oil return passage. If there are machining errors, the depth of the rod part extending into the connecting section can be adjusted by rotating the second limiting member, and the moving stroke of the pressure relief spool can be finely adjusted to ensure the connection stability and reduce the machining accuracy of the main spool and the assembly accuracy of each component.

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

[0019] 1. When the auxiliary spool is in the initial state, the auxiliary spool blocks the inflow hole, and the pressure chamber is connected to the oil return circuit; when the auxiliary spool blocks the outflow hole, the pressure chamber is connected to the oil inlet circuit, and the brake fluid entering the pressure chamber acts on one end of the main spool, causing the main spool to move under the pressure of the oil, that is, the brake fluid provides assistance for the movement of the main spool.

[0020] 2. This application adopts a double-chamber design, that is, two oil chambers for accommodating brake fluid are provided 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 oil chamber. When the main spool moves, the larger oil chamber first delivers brake fluid to the brake to realize the contact between the brake pads and the brake disc in the brake. As the main spool continues to move, on the premise that the force driving the main spool to move remains unchanged, due to the increase in the area ratio of the smaller oil chamber to the main spool, the oil pressure output by the smaller oil chamber increases to meet the pressure required for the brake pads to clamp the brake disc, thereby increasing the braking pressure and the output flow rate at the same time.

[0021] 3. 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 force driving the main spool to move acts completely on the small oil chamber, further increasing the oil pressure that the small oil chamber can output. Brief Description of the Drawings

[0022] Figure 1 is a cross-sectional view of the brake valve in the initial state.

[0023] Figure 2 is Figure 1 a partial enlarged view of A in

[0024] Figure 3 is Figure 1 a partial enlarged view of

[0025] Figure 4 is Figure 3 a partial enlarged view of B in

[0026] Figure 5 is a cross-section of the brake valve in the braking state Figure 1 .

[0027] Figure 6 is Figure 5 a partial enlarged view of C in

[0028] Figure 7 is Figure 5 a partial enlarged view of

[0029] Figure 8 is a cross-section of the brake valve in the braking state Figure 2 .

[0030] Figure 9 is Figure 8 a partially enlarged view of

[0031] Figure 10 is Figure 9 a partially enlarged view of the position D in

[0032] In the figure, 1 is the valve body; 11 is the oil inlet passage; 12 is the oil return passage; 121 is the first oil return hole; 122 is the second oil return hole; 13 is the brake oil passage; 14 is the mounting hole; 141 is the flared section; 142 is the straight hole section; 143 is the outflow hole; 144 is the inflow hole; 145 is the second limit retaining ring; 15 is the pressure chamber; 16 is the pressure relief chamber; 161 is the opening; 162 is the sliding section; 163 is the connecting section; 17 is the contraction part; 171 is the stepped hole; 172 is the stepped surface; 2 is the push rod; 3 is the main spool valve; 31 is the first compression part; 32 is the second compression part; 321 is the first connecting groove; 322 is the second connecting groove; 33 is the assembly hole; 34 is the oil inlet hole; 35 is the oil outlet hole; 4 is the first oil chamber; 5 is the auxiliary spool valve; 51 is the through hole; 6 is the second oil chamber; 61 is the first return spring; 7 is the first one-way component; 71 is the steel ball; 72 is the first limiting component; 8 is the pressure relief spool valve; 81 is the oil passage; 82 is the first connecting hole; 83 is the second connecting hole; 9 is the second limiting component; 91 is the rod part; 92 is the head part; 93 is the first sealing ring; 10 is the first limit retaining ring; 101 is the second return spring; 102 is the third return spring; 103 is the valve sleeve; 104 is the second sealing ring; 105 is the second one-way component; Br is the brake port; T is the oil return port; P is the oil inlet port; PA is the accumulator interface. Specific Embodiments

[0033] The following are specific embodiments of the present invention in combination with the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0034] As shown in Figures 1-4As shown in the figure, this brake valve includes a valve body 1 and a push rod 2. The valve body 1 has an oil inlet oil passage 11, an oil return oil passage 12, and a brake oil passage 13. The oil inlet oil passage 11 has an oil inlet P and an accumulator interface PA located on the outer wall of the valve body 1. The oil return oil passage 12 has an oil return port T located on the outer wall of the valve body 1. The brake oil passage 13 has a brake port Br located on the outer wall of the valve body 1. A main spool 3 is slidably connected inside the valve body 1. There is a first oil chamber 4 and a second oil chamber 6 communicating with the brake oil passage 13 between one end of the main spool 3 and the valve body 1. And the other end of the main spool 3 faces the push rod 2. An installation hole 14 communicating with both the oil inlet oil passage 11 and the oil return oil passage 12 is provided at the end of the main spool 3 facing the push rod 2. An auxiliary spool 5 blocking the communication between the oil inlet oil passage 11 and the oil return oil passage 12 is slidably connected in the installation hole 14. One end of the auxiliary spool 5 is connected to the push rod 2, and a pressure chamber 15 is formed between this end and the main spool 3. The pressure chamber 15 communicates with the oil return oil passage 12 through the auxiliary spool 5. When the push rod 2 drives the auxiliary spool 5 to move, the pressure chamber 15 communicates with the oil inlet oil passage 11 through the auxiliary spool 5. A first one-way component 7 enabling the second oil chamber 6 to conduct to the brake oil passage 13 is provided inside the valve body 1. The other end of the main spool 3 has a pressure relief chamber 16 communicating with both the second oil chamber 6 and the oil return oil passage 12. A pressure relief spool 8 blocking the communication between the oil inlet oil passage 11 and the oil return oil passage 12 is slidably connected in the pressure relief chamber 16. The pressure relief chamber 16 has an opening 161 communicating with the first oil chamber 4. When the oil pressure in the first oil chamber 4 increases and pushes the pressure relief spool 8 to slide, the pressure relief spool 8 slides to make the second oil chamber 6 communicate with the oil return oil passage 12.

[0035] As Figure 3 shown, the inner wall of the valve body 1 has a inwardly protruding and annular constriction 17. The first oil chamber 4 is located radially inside the constriction 17, and the second oil chamber 6 is located axially outside the constriction 17. The main spool 3 has a first compression part 31 sliding against the wall of the first oil chamber 4 in a columnar shape and a second compression part 32 sliding against the wall of the second oil chamber 6. The cross-sectional area of the second compression part 32 is 4 - 8 times that of the first compression part 31. A stepped hole 171 is provided on the constriction 17. The large end of the stepped hole 171 communicates with the brake oil passage 13, and the small end of the stepped hole 171 communicates with the second oil chamber 6. The first one-way component 7 includes a steel ball 71 located in the stepped hole 171. A first limiting part 72 penetrating into the stepped hole 171 is fixedly connected to the valve body 1. The steel ball 71 can roll between the first limiting part 72 and the stepped surface 172 of the stepped hole 171.

[0036] As Figures 1-3As shown in the figure, the oil return circuit 12 is located between the brake oil circuit 13 and the oil inlet circuit 11. The oil return circuit 12 has a first oil return hole 121 and a second oil return hole 122 that are located on the inner wall of the valve body 1 and are spaced along the axial direction of the main spool 3. An annular first communication groove 321 is formed on the upper part of the second compression part 32. The second oil chamber 6 is communicated with the first oil return hole 121 through the first communication groove 321. A first return spring 61 is arranged in the second oil chamber 6, and the first return spring 61 acts on the second compression part 32 elastically. When the main spool 3 is in the initial state, the second oil chamber 6 is communicated with the second oil return hole 122. A second one-way component 105 is arranged on the main spool 3 to conduct the first communication groove 321 to the second oil chamber 6.

[0037] As Figure 1 shown, an assembly hole 33 running through from one end to the other end is formed on the main spool 3. The brake valve further includes a second limiting member 9. The second limiting member 9 is threadedly connected in the assembly hole 33 and divides the assembly hole 33 into the above-mentioned installation hole 14 and the pressure relief chamber 16. The opening 161 of the pressure relief chamber 16 is located on the end face of the main spool 3. A first limiting retaining ring 10 is positioned at the opening 161 of the pressure relief chamber 16. The pressure relief chamber 16 includes a sliding section 162 in the shape of a circular hole and a connecting section 163. The aperture of the connecting section 163 is larger than that of the sliding section 162. One end of the connecting section 163 is connected to the sliding section 162, and the other end of the connecting section 163 has a thread. The second limiting member 9 has a rod portion 91 passing through the connecting section 163 and a head portion 92 abutting against the bottom of the installation hole 14. The head portion 92 and the rod portion 91 are of an integral structure. The rod portion 91 is stepped and threadedly connected to the connecting section 163. A first sealing ring 93 with an outer ring abutting against the connecting section 163 is sleeved on the rod portion 91. The head portion 92 abuts against the first sealing ring 93, and a third return spring 102 is sleeved outside the head portion 92. One end of the third return spring 102 abuts against the bottom of the installation hole 14, and the other end of the third return spring 102 abuts against the end of the auxiliary spool 5. A second return spring 101 that elastically acts on one end of the pressure relief spool 8 and makes the other end of the pressure relief spool 8 abut against the first limiting retaining ring 10 is sleeved on the rod portion 91. An oil inlet hole 34 communicating the second oil chamber 6 and the sliding section 162 and an oil outlet hole 35 communicating the first communication groove 321 and the connecting section 163 are formed on the main spool 3. The pressure relief spool 8 is columnar and slidably connected to the sliding section 162. An oil passing circuit 81 is formed in the pressure relief spool 8. The oil passing circuit 81 has a first communication hole 82 and a second communication hole 83 located on the outer wall of the pressure relief spool 8. The first communication hole 82 can be communicated with the oil inlet hole 34. The second communication hole 83 is located in the connecting section 163. When the pressure relief spool 8 abuts against the end face of the rod portion 91, the first communication hole 82 is communicated with the oil inlet hole 34. A second sealing ring 104 that abuts against the wall surface of the sliding section 162 is sleeved on the pressure relief spring. The second sealing ring 104 prevents the oil in the first oil chamber 4 from entering the second oil chamber 6.

[0038] As shown Figures 5-6 in the figure, a ring-shaped second communication groove 322 is formed in the upper part of the second compression part 32. The second communication groove 322 is communicated with the oil inlet oil path 11. The installation hole 14 includes a flared section 141 and a straight hole section 142 in the shape of a round hole. The auxiliary valve core 5 is columnar and is slidably connected with the straight hole section 142. An inflow hole 144 and an outflow hole 143 are formed on the wall surface of the straight hole section 142 at intervals along the axial direction of the main valve core 3. The outflow hole 143 is communicated with the first communication groove 321, and the inflow hole 144 is communicated with the second communication groove 322. The aperture of the flared section 141 gradually decreases from the end face of the main valve core 3 towards the straight hole section 142. The pressure chamber 15 is located between the wall surface of the flared section 141 and the auxiliary valve core 5. A second limit retaining ring 145 is fixedly connected to the wall surface of the small end of the flared section 141. The auxiliary valve core 5 abuts against the second limit retaining ring 145 under the elastic force of the third return spring 102. The brake valve further includes a valve sleeve 103 slidably connected in the valve body 1. One end of the valve sleeve 103 is fixedly connected to the push rod 2. The other end of the valve sleeve 103 extends into the flared section 141 and is connected to the auxiliary valve core 5, and the valve sleeve 103 can abut against the first limit retaining ring 10.

[0039] As shown Figures 1-4 in the figure, when the main valve core 3 is in the initial state, the second oil chamber 6 is communicated with the oil return port T through the second oil return hole 122. The pressure relief valve core 8 blocks the orifice of the oil inlet hole 34, cutting off the communication between the second oil chamber 6 and the oil return oil path 12. The auxiliary valve core 5 blocks the inflow hole 144, cutting off the communication between the pressure chamber 15 and the oil inlet oil path 11. At this time, the pressure chamber 15 is communicated with the oil return oil path 12. As shown Figure 5 in the figure, when the driver steps on the brake pedal, as shown Figure 6 in the figure, the push rod 2 overcomes the elastic force of the third return spring 102 through the valve sleeve 103, driving the auxiliary valve core 5 to move leftward. The auxiliary valve core 5 blocks the orifice of the outflow hole 143, cutting off the communication between the pressure chamber 15 and the oil return oil path 12, and connecting the pressure chamber 15 and the oil inlet oil path 11. The brake fluid enters the pressure chamber 15 and acts on one end of the main valve core 3. As shown Figure 7 in the figure, the main valve core 3 moves leftward against the elastic force of the first return spring 61, cutting off the communication between the second oil return hole 122 and the oil return port T. The main valve core 3 continues to move leftward, compressing the brake fluid in the second oil chamber 6, causing the second oil chamber 6 to start building pressure. When the oil pressure in the second oil chamber 6 is greater than the pressure in the brake oil path 13, since the first oil chamber 4 is communicated with the brake oil path 13, the pressure in the first oil chamber 4 is also lower than that in the second oil chamber 6. The steel ball 71 abuts against the first limiting member 72 under the pressure of the second oil chamber 6. The brake fluid in the second oil chamber 6 flows into the brake oil path 13 through the stepped hole 171, and the pressurized brake fluid is output 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 path 13 is basically equivalent to that of the brake. As shown Figures 8-9As shown, when the hydraulic pressure in the brake oil circuit 13 is greater than that in the second oil chamber 6, the steel ball 71 abuts against the stepped surface 172 under the pressure of the brake oil circuit 13, disconnecting the connection between the second oil chamber 6 and the brake oil circuit 13. At this time, the hydraulic pressure in the first oil chamber 4 is also greater than that in the second oil chamber 6. As Figure 10 shown, the brake fluid in the first oil chamber 4 enters the relief chamber 16 through the opening 161 of the relief chamber 16 and acts on one end of the relief valve core 8, causing the relief valve core 8 to move rightward relative to the main valve core 3 against the elastic force of the second return spring 101. When the relief valve core 8 abuts against the end face of the rod portion 91 of the second limiting member 9, the first communication hole 82 is completely communicated with the oil inlet hole 34, so that the brake fluid in the second oil chamber 6 flows out through the second communication hole 83 and then flows to the oil return circuit 12 through the oil outlet hole 35, relieving the pressure in the second oil chamber 6. The leftward movement of the main valve core 3 will compress the first oil chamber 4, and the acting force applied to the main valve core 3 acts on the first oil chamber 4. Since the cross-sectional area of the second compression portion 32 is 4-8 times that of the first compression portion 31, the compression of the first oil chamber 4 will output a hydraulic pressure greater than that in the second oil chamber 6 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 auxiliary valve core 5 resets under the elastic force of the third return spring 102, disconnecting the connection between the pressure chamber 15 and the oil inlet circuit 11 and connecting the pressure chamber 15 and the oil return circuit 12, so that the pressure chamber 15 is unloaded. The main valve core 3 moves rightward under the elastic force of the first return spring 61, and the hydraulic fluid of the brake flows back to the brake valve through the brake port Br. The returned brake fluid fills the first oil chamber 4. At this time, the second one-way component 105 opens, so that the hydraulic fluid in the oil return circuit 12 enters the second oil chamber 6 through the oil replenishing circuit, preventing the second oil chamber 6 from being emptied. The relief valve core 8 moves leftward under the elastic force of the second return spring 101, and the relief valve core 8 abuts against the limit retaining ring again, so that the relief valve core 8 cuts off the connection between the second oil chamber 6 and the oil return circuit 12. When the brake valve returns to the initial state, the second one-way component 105 closes, and the second oil chamber 6 is reconnected to the second oil return hole 122. At this time, the oil return port T can be used as the oil replenishing port for the second oil chamber 6, that is, the brake fluid can be replenished to the second oil chamber 6 through the oil return port T.

[0040] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0041] Although terms such as valve body 1, inlet oil passage 11, return oil passage 12, first return oil hole 121, second return oil hole 122, brake oil passage 13, mounting hole 14, flared section 141, straight hole section 142, outflow hole 143, inflow hole 144, second limiting retaining ring 145, pressure chamber 15, pressure relief chamber 16, opening 161, sliding section 162, connecting section 163, constriction 17, stepped hole 171, stepped surface 172, push rod 2, main spool 3, first compression section 31, second compression section 32, first communication groove 321, second communication groove 322, assembly hole 33, inlet oil hole 34, outlet oil hole 35, first oil chamber 4, auxiliary spool 5, through hole 51, second oil chamber 6, first return spring 61, first one-way assembly 7, steel ball 71, first limiting member 72, pressure relief spool 8, oil passing passage 81, first communication hole 82, second communication hole 83, second limiting member 9, rod portion 91, head portion 92, first sealing ring 93, first limiting retaining ring 10, second return spring 101, third return spring 102, valve sleeve 103, second sealing ring 104, second one-way assembly 105, brake port Br, return port T, inlet port P, accumulator interface PA are used more frequently in this text, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any kind of additional limitation is contrary to the spirit of the present invention.

Claims

1. A brake valve, comprising a valve body (1) and a push rod (2), wherein the valve body (1) has an oil inlet circuit (11), an oil return circuit (12) and a brake circuit (13), and a main valve core (3) is slidably connected to the valve body (1), characterized in that: A first oil chamber (4) is formed between one end of the main valve core (3) and the valve body (1), and the first oil chamber (4) is connected to the brake oil circuit (13). The main valve core (3) has a mounting hole (14) that is connected to both the oil inlet circuit (11) and the oil return circuit (12). An auxiliary valve core (5) is slidably arranged in the mounting hole (14) to block the connection between the oil inlet circuit (11) and the oil return circuit (12). A pressure chamber (15) is formed between one end of the auxiliary valve core (5) and the main valve core (3), and the auxiliary valve core (5) is connected to the push rod (2). The pressure chamber (15) is connected to the oil return circuit (12) through the auxiliary valve core (5). When the push rod (2) drives the auxiliary valve core (5) to move, the pressure chamber (15) is connected to the oil inlet circuit (11) through the auxiliary valve core (5). A second oil chamber (6) is also formed between the main valve core (3) and the valve body (1), and the second oil chamber (6) is connected to the oil return circuit (12). The first oil chamber (6) and the first oil chamber (4) are both located at one end of the main valve core (3); the oil return passage (12) is located between the brake oil passage (13) and the oil inlet passage (11); the oil return passage (12) has a first oil return hole (121) and a second oil return hole (122) arranged at intervals along the axial direction of the main valve core (3); the main valve core (3) has a second compression portion (32) in a columnar shape and sliding against the cavity wall of the second oil chamber (6); a first annular communication groove (321) is provided on the second compression portion (32); the second oil chamber (6) is communicated with the first oil return hole (121) through the first communication groove (321); a first return spring (61) located in the second oil chamber (6) is sleeved on the main valve core (3); the first return spring (61) elastically acts on the second compression portion (32); the second oil chamber (6) can be communicated with the second oil return hole (122).

2. The brake valve according to claim 1, characterized in that: The valve body (1) is provided with a first one-way component (7) capable of connecting the second oil chamber (6) to the brake oil circuit (13); the main valve core (3) is also provided with a pressure relief chamber (16) connected to both the second oil chamber (6) and the oil return circuit (12); a pressure relief valve core (8) capable of blocking the connection between the second oil chamber (6) and the oil return circuit (12) is slidably provided in the pressure relief chamber (16); the pressure relief chamber (16) has an opening (161) connected to the first oil chamber (4); when the oil pressure in the first oil chamber (4) increases and pushes the pressure relief valve core (8) to slide, the second oil chamber (6) and the oil return circuit (12) are connected.

3. The brake valve according to claim 2, characterized in that: The main valve core (3) is provided with an assembly hole (33) extending from one end to the other end. The brake valve further comprises a second stopper (9), wherein the second stopper (9) is threadedly connected in the assembly hole (33) and separates the assembly hole (33) into the above-mentioned mounting hole (14) and the pressure relief chamber (16).

4. The brake valve according to claim 3, characterized in that: The second limiting member (9) further comprises a head portion (92) abutting against the bottom of the mounting hole (14) and a rod portion (91) screwed to the pressure relief chamber (16); the rod portion (91) is stepped; the head portion (92) and the rod portion (91) are an integrated structure; a first sealing ring (93) is provided between the rod portion (91) and the cavity wall of the pressure relief chamber (16); the head portion (92) abuts against the first sealing ring (93); a third return spring (102) is provided on the outer sleeve of the head portion (92); one end of the third return spring (102) abuts against the bottom of the mounting hole (14); and the other end of the third return spring (102) abuts against the end of the auxiliary valve core (5).

5. The brake valve according to claim 4, characterized in that: The second compression portion (32) is also provided with a second communicating groove (322) in the shape of an annulus, the second communicating groove (322) being communicated with the oil inlet passage (11), the mounting hole (14) comprising a flared section (141) and a straight hole section (142) in the shape of a circular hole, the auxiliary valve core (5) being columnar and slidably connected to the straight hole section (142), the wall surface of the straight hole section (142) being provided with outflow holes (143) and flow holes (144) arranged at intervals along the axial direction of the main valve core (3) The inlet hole (144) and the outlet hole (143) are connected to the first connecting groove (321), the inlet hole (144) is connected to the second connecting groove (322), the brake valve also includes a valve sleeve (103) slidably connected to the valve body (1), the pressure chamber (15) is located between the wall surface of the expansion section (141) and the auxiliary valve core (5), one end of the valve sleeve (103) is fixedly connected to the push rod (2), and the other end of the valve sleeve (103) is connected to the auxiliary valve core (5).

6. The brake valve according to claim 5, characterized in that The aperture of the expanded section (141) gradually decreases from the end face of the main valve core (3) toward the straight hole section (142), and a second limit retaining ring (145) is fixedly connected to the wall surface of the small end of the expanded section (141). The valve sleeve (103) extends into the expanded section (141), and the valve sleeve (103) can abut against the first limit retaining ring (10), and the auxiliary valve core (5) abuts against the second limit retaining ring (145) under the elastic force of the third return spring (102).

7. The brake valve according to claim 6, characterized in that One end of the auxiliary valve core (5) extends out of the second limit retaining ring (145) and is clamped with the valve sleeve (103), and the auxiliary valve core (5) has a through hole (51) extending from one end to the other end, and the pressure chamber (15) is connected to the inflow hole (144) or the outflow hole (143) through the through hole (51).

8. The brake valve according to any one of claims 1 to 7, characterized in that: The inner wall of the valve body (1) has an inwardly protruding annular contraction portion (17), the first oil chamber (4) is located radially inside the contraction portion (17), the second oil chamber (6) is located axially outside the contraction portion (17), the main valve core (3) also has a first compression portion (31) which is columnar and slides against the wall of the first oil chamber (4), and the cross-sectional area of ​​the second compression portion (32) is 4 to 8 times the cross-sectional area of ​​the first compression portion (31).

9. The brake valve according to any one of claims 4 to 7, characterized in that: The opening (161) of the pressure relief chamber (16) is located on the end surface of the main valve core (3); a first limit retaining ring (10) is positioned at the opening (161) of the pressure relief chamber (16); the pressure relief chamber (16) comprises a sliding section (162) and a connecting section (163) in the shape of a circular hole; the hole diameter of the connecting section (163) is larger than the hole diameter of the sliding section (162); one end of the connecting section (163) is connected to the sliding section (162), and the other end of the connecting section (163) has a The rod (91) is threadedly connected to the connecting section (163). A second return spring (101) is sleeved on the rod (91) and elastically acts on one end of the pressure relief valve core (8) to make the other end of the pressure relief valve core (8) abut against the first limit retaining ring (10). The pressure relief valve core (8) has an oil passage (81). When the pressure relief valve core (8) abuts against the end surface of the rod (91), the second oil chamber (6) is connected to the oil return passage (12) through the pressure relief chamber (16).

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