Relay valve with kink characteristic and braking method thereof

Abstract

The invention discloses a relay valve with a kink characteristic and a braking method thereof. The relay valve comprises a control pressure cavity, a relay valve BC pressure piston, a BC pressure acting part, a kink valve piston and a kink valve pressure limiting part. According to the braking method, after the right cavity of the right piston enters pressure, the right piston reversely moves leftwards under the action of the pressure of the left cavity and the right cavity, under the heavy load condition, a BC pressure acting part valve port is closed under the action of the right piston, along with rising of control pressure, a kink valve pressure limiting part is closed, and the pressure in the right cavity of the left piston is constant; the pressure of the left cavity of the left piston is larger than that of the right cavity of the left piston, the left piston moves rightwards under the action of the pressure of the left cavity and the right cavity, a valve port of the BC pressure acting part is pushed to be opened through the right piston till the valve port is completely opened, and the kink action is finished. The invention has the beneficial effects of simple principle, compact structure and high product integration level, and can be used for an SS-pole truck which is only provided with a tread brake.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of railway freight car braking system, and particularly relates to a relay valve with kink characteristics for UIC (International Union of Railways) standards. BACKGROUND

[0002] The relay valve meeting the UIC standard is a key part in the railway freight car braking system, and its main function is to amplify the signal from the distribution valve according to the load condition of the vehicle, output to the brake cylinder, shorten the brake response time, and automatically distribute the brake cylinder pressure to achieve the purpose that the braking force is proportional to the vehicle load.

[0003] In some countries, there are SS-level freight vehicles and S-level freight vehicles in railway freight vehicles. In terms of braking force, the braking force of the SS-level freight vehicle is greater than that of the S-level freight vehicle. When the two types of vehicles are mixed, the SS-level freight vehicle will bear more braking work, and if the freight car is only equipped with tread brake, it will cause excessive thermal load of the wheel during continuous downhill process.

[0004] Therefore, a relay valve with kink characteristics is needed, which has the characteristics of reducing the output pressure (brake cylinder pressure) under low braking demand, and the output pressure should be close to and finally restore the pressure value required under the current load condition under medium to high braking demand, so as to realize the braking performance equivalent to the pressure value under the maximum load and the maximum braking force, as shown in Figure 1 SUMMARY

[0005] The application provides a relay valve with kink characteristics, which solves the problem of kink characteristics of the relay valve.

[0006] The application achieves the purpose by the following technical scheme. A relay valve with kink characteristics, comprising a control pressure cavity and a relay valve BC pressure piston, further comprising a kink valve piston, the kink valve piston comprising a left piston and a right piston, the control pressure cavity being in communication with a left cavity of the left piston and a left cavity of the right piston of the kink valve piston respectively, the left cavity of the right piston being in communication with a kink valve pressure limiting part, the kink valve pressure limiting part being in communication with a right cavity of the left piston of the kink valve piston, the relay valve BC pressure piston being in communication with a right cavity of a BC pressure acting part, a left cavity of the BC pressure acting part being in communication with a right cavity of the right piston of the kink valve piston, and the right cavity of the right piston being in communication with a brake cylinder pressure cavity.

[0007] ​Further, it also includes a sub-air cylinder pressure chamber, the control pressure chamber is communicated with the BC jump limiting pressure part, the BC jump limiting pressure part is communicated with the relay valve BC pressure piston right chamber, the sub-air cylinder pressure chamber is communicated with the CV' pressure acting part left chamber, the CV' pressure acting part right chamber is communicated with the relay valve BC pressure piston left chamber, the relay valve BC pressure piston left chamber is communicated with the BC pressure acting part right chamber, the control pressure chamber is communicated with the CV pressure piston, the other end of the CV pressure piston is connected with the right end of the relay valve BC pressure piston.

[0008] Further, it also includes an empty weight adjustment part for adjusting the CV pressure piston fulcrum position, the empty weight adjustment part has an empty weight signal control pressure chamber.

[0009] Further, the left chamber of the left piston of the kink valve piston is equal in area, and the left chamber of the right piston of the kink valve piston is unequal in area.

[0010] Further, the left chamber of the right piston of the kink valve piston is smaller in acting area than the right chamber.

[0011] A brake method of a relay valve with kink characteristics, including a control pressure chamber and a relay valve BC pressure piston, in the brake position, the control pressure of the control pressure chamber enters the left chamber of the left piston and the left chamber of the right piston of the kink valve piston respectively, the pressure of the right chamber of the right piston enters the right chamber of the left piston of the kink valve piston through the kink valve limiting pressure part, the CV' pressure of the relay valve BC pressure piston enters the right chamber of the BC pressure acting part, the left piston of the kink valve piston does not act on the right piston under the action of the pressure in the left and right chambers, the right piston of the kink valve piston moves right under the action of the pressure in the left chamber and pushes the BC pressure acting part valve port to open, the CV' pressure in the right chamber of the BC pressure acting part sequentially passes through the BC pressure acting part valve port, the left chamber of the BC pressure acting part, the right chamber of the right piston of the kink valve piston, enters the brake cylinder pressure chamber and forms the brake cylinder pressure, and generates the jump pressure.

[0012] After the right chamber of the right piston enters the pressure, the right piston of the kink valve piston reversely moves left under the action of the pressure in the left and right chambers, in the empty load and intermediate load conditions, the BC pressure acting part valve port keeps completely open under the action of the right piston, with the increase of the control pressure, the brake cylinder pressure continuously increases and performs the brake action; in the heavy load condition, the BC pressure acting part valve port is closed under the action of the right piston, the kink action starts, with the increase of the control pressure, the kink valve limiting pressure part closes, the pressure in the right chamber of the left piston is constant, the pressure in the left chamber of the left piston is greater than that in the right chamber of the left piston, the left piston of the kink valve piston moves right under the action of the pressure in the left and right chambers, the right moving left piston pushes the BC pressure acting part valve port to open until completely open through the right piston, the kink action ends, and the brake cylinder pressure continuously increases and performs the brake action.

[0013] Furthermore, the aforementioned relay valve with kinking characteristics is used.

[0014] Furthermore, it also includes the auxiliary air cylinder pressure chamber. In the initial inflation position, the auxiliary air cylinder pressure in the auxiliary air cylinder pressure chamber enters the left chamber of the CV' pressure action part. Furthermore, in the braking position, the control pressure of the control pressure chamber enters the right chamber of the relay valve BC pressure piston through the BC rise pressure limiting part. Under the action of the right chamber pressure, the relay valve BC pressure piston moves to the left and pushes the valve port of the CV' pressure action part to open. The auxiliary air cylinder pressure in the left chamber of the CV' pressure action part enters the right chamber and forms the CV' pressure. The CV' pressure enters the relay valve BC pressure piston and then enters the right chamber of the BC pressure action part. The control pressure of the control pressure chamber enters the CV pressure piston. As the control pressure increases, the BC rise pressure limiting part closes, and the pressure in the right chamber of the relay valve BC pressure piston remains constant. At the same time, the CV pressure piston moves under the action of the control pressure, pushing the relay valve BC pressure piston to the left, widening the valve port of the CV' pressure action part, and increasing the CV' pressure.

[0015] In the brake pressure holding position, the CV' pressure increases, and the pressure in the left chamber of the relay valve BC pressure piston is balanced with the pressure in the right chamber and the pressure acting on the CV pressure piston. The balanced relay valve BC pressure piston causes the valve port of the CV' pressure acting part to close, and the CV' pressure stops rising. The pressure in the left chamber of the left piston and the pressure in the left chamber of the right piston are balanced with the pressure in the right chamber of the left piston and the right chamber of the right piston. The balanced toggle valve piston causes the valve port of the BC pressure acting part to close, and the brake cylinder pressure stops rising.

[0016] In the relief position, the control pressure is discharged through the distribution valve and the pressure decreases. The effect of the control pressure on the CV pressure piston weakens, and the effect of the CV pressure piston on the relay valve BC pressure piston weakens. The relay valve BC pressure piston moves to the right, the valve port of the CV' pressure action part closes, and the CV' pressure is discharged to the atmosphere through the internal air passage of the relay valve BC pressure piston. The BC rise pressure limiting part opens, and the pressure in the right chamber of the relay valve BC pressure piston is discharged through the distribution valve. The pressure in the left chamber of the left piston and the left chamber of the right piston decreases along with the control pressure. The kink valve piston moves to the left, the valve port of the BC pressure action part closes, and the brake cylinder pressure is discharged to the atmosphere through the internal air passage of the BC pressure action part. The kink valve pressure limiting part opens, and the pressure in the right chamber of the left piston is discharged through the distribution valve.

[0017] Furthermore, in the initial inflation position, the empty weight signal control pressure enters the empty weight signal control pressure chamber of the empty weight adjustment section. Different empty weight signal control pressures correspond to different fulcrum positions of the CV pressure piston. The CV pressure piston converts the control pressure into a force acting on the relay valve BC pressure piston through a lever structure.

[0018] Furthermore, in the braking position, the left and right chambers of the left piston of the kink valve piston have equal areas. Under the action of equal pressure and equal area in the left and right chambers, the left piston of the kink valve piston remains in balance and does not move the right piston. The left and right chambers of the right piston of the kink valve piston have unequal areas. After the right chamber of the right piston is pressurized, the right piston of the kink valve piston moves to the left and in the opposite direction under the action of unequal areas in the left and right chambers.

[0019] Furthermore, in the braking position, the working area of ​​the left chamber of the right piston of the toggle valve is smaller than that of the right chamber. After the right chamber of the right piston is pressurized, the right piston of the toggle valve moves to the left in the opposite direction under the action of the small area of ​​the left chamber with high pressure and the large area of ​​the right chamber with low pressure.

[0020] The beneficial effects of this application are: the relay valve can reduce the output pressure (brake cylinder pressure) under low braking demand, and the output pressure will approach and eventually recover the pressure value required under the current load conditions under medium to high braking demand, so as to achieve braking performance equivalent to the pressure value under maximum load and maximum braking force. Its principle is simple, its structure is compact, and its product integration is high. It can be used in SS-pole freight cars equipped only with tread brakes, and can prevent wheel overheating, especially when the vehicle is under heavy load and traveling long distances downhill.

[0021] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0022] Figure 1 This is a characteristic diagram showing the relationship between the output pressure and input pressure of the relay valve in this application.

[0023] Figure 2 This is a schematic diagram of the relay valve structure in this application.

[0024] Figure 3 This is a schematic diagram of the initial gas charging position structure of the relay valve in this application.

[0025] Figure 4 This is a schematic diagram of the relay valve braking position structure in this application.

[0026] Figure 5 This is a schematic diagram of the relay valve braking and pressure holding position structure in this application.

[0027] Figure 6 This is a schematic diagram of the relay valve release position structure in this application.

[0028] Figure 1In the diagram: Pi - Input pressure (kPa), Po - Output pressure (kPa), Line 2 - Input-output relationship under no-load (LCP-X), Line 3 - Input-output relationship under intermediate load (LCP-Y), Line 4 - Input-output relationship under heavy load (LCP-Z).

[0029] Figures 2-6 In the middle: 1-BC pressure limiting part, 2-CV' pressure acting part, 3-relay valve BC pressure piston, 4-empty weight adjustment part, 5-CV pressure piston, 6-BC pressure acting part, 7-torsion valve piston, 8-torsion valve pressure limiting part; 701-left chamber of left piston, 702-right chamber of left piston, 703-left chamber of right piston, 704-right chamber of right piston, 705-blocking; AR-auxiliary air cylinder pressure, CV-control pressure, BC-brake cylinder pressure, T-empty weight signal control pressure, EX1-brake cylinder pressure exhaust port, EX2-CV' exhaust port. Detailed Implementation

[0030] The following non-limiting embodiments are used to illustrate this application.

[0031] Example 1 refer to Figures 1-6 As shown, a relay valve with kinking characteristics includes a secondary air cylinder pressure chamber, a control pressure chamber, a brake cylinder pressure chamber, a BC rise pressure limiting part 1, a CV' pressure acting part 2, a relay valve BC pressure piston 3, an empty weight adjustment part 4, a CV pressure piston 5, a BC pressure acting part 6, a kinking valve piston 7, and a kinking valve pressure limiting part 8.

[0032] The auxiliary air cylinder pressure chamber is used to provide the auxiliary air cylinder pressure AR, the control pressure chamber is used to provide the control pressure CV, and the brake cylinder pressure chamber is used to provide the brake cylinder pressure BC.

[0033] The control pressure chamber is connected to the BC rise pressure limiting part 1, and the BC rise pressure limiting part 1 is connected to the right chamber of the relay valve BC pressure piston 3. The BC rise pressure limiting part 1 is used to control whether the pressure chamber is connected to the right chamber of the relay valve BC pressure piston 3. That is, when the control pressure CV is below the limit pressure (low pressure), the BC rise pressure limiting part 1 remains open, and when the control pressure CV is above the limit pressure (high pressure), the BC rise pressure limiting part 1 remains closed.

[0034] The auxiliary air cylinder pressure chamber is connected to the left chamber of the CV' pressure action part 2, and the right chamber of the CV' pressure action part 2 is connected to the left chamber of the relay valve BC pressure piston 3. The CV' pressure action part 2 can control the connection between its left and right chambers by opening and closing its own valve port. After the auxiliary air cylinder pressure AR enters the left chamber of the CV' pressure action part 2, it is converted into VC' pressure in the right chamber through the valve port and enters the left chamber of the relay valve BC pressure piston 3.

[0035] The relay valve BC pressure piston 3 acts on the CV' pressure action part 2 to control the opening and closing of the valve port of the CV' pressure action part 2 itself. The relay valve BC pressure piston 3 has left and right chambers, and the right end of the relay valve BC pressure piston 3 is connected to the CV pressure piston 5. That is, the relay valve BC pressure piston 3 moves under the combined action of the pressure in the left and right chambers and the force of the CV pressure piston 5.

[0036] The empty weight adjustment unit 4 is used to adjust the fulcrum position of the CV pressure piston 5, so that the CV pressure piston 5 itself forms different lever relationships to adjust the pressure proportionally for different load conditions. The empty weight adjustment unit 4 has an empty weight signal control pressure chamber, to which the empty weight signal control pressure T is sent. By converting the pressure into mechanical motion, the fulcrum position of the empty weight adjustment unit 4 is adjusted and changed.

[0037] The CV pressure piston 5 is used for force conversion. The control pressure chamber is connected to the CV pressure piston 5, and the other end of the CV pressure piston 5 is connected to the right end of the relay valve BC pressure piston 3. The control pressure CV is converted into a force on the relay valve BC pressure piston 3 through the lever structure of the CV pressure piston 5 itself.

[0038] The left chamber of the relay valve BC pressure piston 3 is connected to the right chamber of the BC pressure action part 6. The left chamber of the BC pressure action part 6 is connected to the right chamber 704 of the right piston of the toggle valve piston 7. The BC pressure action part 6 can control the connection between its left and right chambers by opening and closing its own valve port. After the CV' pressure enters the right chamber of the BC pressure action part 6, it is converted into the brake cylinder pressure BC in the left chamber through the valve port and enters the right chamber 704 of the right piston.

[0039] The kink valve piston 7 is used to achieve the kink characteristic. The kink valve piston 7 includes a left piston and a right piston. The control pressure chamber is connected to the left chamber 701 of the left piston and the left chamber 703 of the right piston, respectively. The left chamber 703 of the right piston is connected to the pressure limiting part 8 of the kink valve. The pressure limiting part 8 of the kink valve is connected to the right chamber 702 of the left piston of the kink valve piston 7. The left chamber of the BC pressure action part 6 is connected to the right chamber 704 of the right piston of the kink valve piston 7. The right chamber 704 of the right piston is connected to the pressure chamber of the brake cylinder. A constriction plug 705 is provided at the inlet of the left chamber 701 of the left piston.

[0040] The right piston of the toggle valve piston 7 moves under the combined pressure of the left chamber 703 and the right chamber 704 of the right piston. The right piston directly acts on the BC pressure action part 6 to control the opening and closing of the valve port of the BC pressure action part 6. In the braking position, since the valve port of the BC pressure action part 6 is closed, there is no pressure in the right chamber 704 of the right piston. Therefore, under the pressure of the left chamber 703 of the right piston, the right piston directly pushes the valve port of the BC pressure action part 6 to open. Then, due to the pressure in the right chamber 704 of the right piston, the right piston is subjected to a leftward force. In this case, the valve port of the BC pressure action part 6 may be affected and closed slightly or not at all.

[0041] The left piston of the toggle valve piston 7 moves under the combined pressure of the left chamber 701 and the right chamber 702 of the left piston. When in the braking position, the control pressure CV is below the limit pressure, and the pressure limiting part 8 of the toggle valve remains open. The left piston of the toggle valve piston 7 does not move the right piston under the pressure of the left and right chambers. When the control pressure CV is above the limit pressure, the pressure limiting part 8 of the toggle valve remains closed, and the pressure in the right chamber 702 of the left piston is constant. The control pressure CV gradually increases, making the pressure in the left chamber 701 of the left piston greater than the pressure in the right chamber 702 of the left piston. The left piston of the toggle valve piston 7 moves to the right under the pressure of the left and right chambers. The left piston moving to the right pushes the valve port of the BC pressure action part 6 to open wider or has no effect through the right piston.

[0042] The left piston of the kink valve piston 7 is preferably of equal area in both the left and right chambers. In the braking position, when the pressure limiting part 8 of the kink valve is kept open, the left piston of the kink valve piston 7 is kept in balance by the combined action of equal pressure and equal area in the left and right chambers of the left piston, and the right piston is not moved.

[0043] The right-side piston of the kink valve piston 7 preferably has unequal areas in its left and right chambers. This allows the right piston to move to the left after pressure is applied to its right chamber 704 in the braking position, creating a pressure difference due to the area difference. More preferably, the left chamber of the right-side piston of the kink valve piston 7 has a smaller effective area than the right chamber, so that a smaller pressure in the right chamber pushes the right piston to the left. Depending on design requirements, the left chamber may also have a larger effective area than the right chamber, allowing a larger pressure in the right chamber to push the right piston to the left.

[0044] Example 2 refer to Figures 1-6 As shown, a braking method for a relay valve with kinking characteristics includes the relay valve with kinking characteristics of Example 1. The braking method includes four operating positions: initial inflation position, braking position, braking pressure holding position, and release position.

[0045] refer to Figure 3As shown, in the initial inflation position, the auxiliary air cylinder pressure AR in the auxiliary air cylinder pressure chamber enters the left chamber of the CV' pressure action section 2. The weighing valve outputs a corresponding empty weight signal control pressure T according to the vehicle's load condition. The empty weight signal control pressure T enters the empty weight signal control pressure chamber of the empty weight adjustment section 4. Different empty weight signal control pressures T correspond to different fulcrum positions of the CV pressure piston 5.

[0046] refer to Figure 4 As shown, in the braking position, a jump pressure is first formed. The control pressure CV of the control pressure chamber enters the right chamber of the relay valve BC pressure piston 3 through the BC jump pressure limiting part 1. Under the pressure in the right chamber, the relay valve BC pressure piston 3 moves to the left and pushes the valve port of the CV' pressure action part 2 to open. The auxiliary air cylinder pressure AR in the left chamber of the CV' pressure action part 2 enters the right chamber and forms the CV' pressure. The CV' pressure enters the relay valve BC pressure piston 3 and then enters the right chamber of the BC pressure action part 6. The control pressure CV of the control pressure chamber enters the CV pressure piston 5. Due to the spring action on the right side of the CV pressure piston 5, the braking action cannot be initiated immediately.

[0047] The control pressure CV of the control pressure chamber enters the left chamber 701 of the left piston and the left chamber 703 of the right piston of the toggle valve piston 7 respectively. The inlet of the left chamber 701 of the left piston is provided with a constriction plug 705. The pressure of the left chamber 703 of the right piston enters the right chamber 702 of the left piston of the toggle valve piston 7 through the pressure limiting part 8 of the toggle valve. The CV' pressure of the relay valve BC pressure piston 3 enters the right chamber of the BC pressure action part 6. The left piston of the toggle valve piston 7 does not move the right piston under the action of the pressure of the left and right chambers. The right piston of the toggle valve piston 7 moves to the right under the action of the pressure of the left chamber and pushes the valve port of the BC pressure action part 6 to open. The CV' pressure of the right chamber of the BC pressure action part 6 enters the brake cylinder pressure chamber in sequence through the valve port of the BC pressure action part 6, the left chamber of the BC pressure action part 6, and the right chamber 704 of the right piston of the toggle valve piston 7 and forms the brake cylinder pressure BC, generating a jump pressure.

[0048] As the control pressure CV increases, the BC rise limiting part 1 closes, the pressure in the right chamber of the relay valve BC pressure piston 3 remains constant, and at the same time, the CV pressure piston 5 moves under the action of the control pressure CV, overcoming the spring force on the right side. The CV pressure piston 5 converts the control pressure CV into a force on the relay valve BC pressure piston 3 through the lever structure, pushing the relay valve BC pressure piston 3 to move to the left. The valve port of the CV' pressure action part 2 opens wider, the CV' pressure increases, and the brake cylinder pressure BC continuously increases with the CV' pressure and performs braking.

[0049] After pressure enters the right chamber 704 of the right piston, the right piston of the toggle valve piston 7 moves to the left and in the opposite direction under the pressure of the left and right chambers, in both no-load and intermediate-load conditions (corresponding to the attached diagram). Figure 1(Lines 2 and 3 in the diagram), the valve port of the BC pressure action section 6 remains fully open under the action of the right piston (so that the lines maintain their original slope). As the control pressure CV increases, the brake cylinder pressure BC continuously increases and performs braking.

[0050] Under heavy load conditions (corresponding appendix) Figure 1 (Line 4) The valve port of the BC pressure action part 6 closes slightly under the action of the right piston (the first inflection point of the kink in line 4; due to the valve port closing, the subsequent slope is less than the original slope), and the kink action begins. As the control pressure CV increases, the pressure limiting part 8 of the kink valve closes, the pressure in the right chamber 702 of the left piston remains constant, and the pressure in the left chamber 701 of the left piston is greater than the pressure in the right chamber 702 of the left piston. The left piston of the kink valve piston 7 moves to the right under the action of the pressure in the left and right chambers. The left piston moving to the right pushes the valve port of the BC pressure action part 6 to open wider through the right piston (the second inflection point of the kink in line 4; due to the valve port opening wider, the subsequent slope is greater than the original slope) until it is fully open (the third inflection point of the kink in line 4; at this time, the valve port is fully open, and the subsequent slope returns to the original slope), and the kink action ends.

[0051] Preferably, the left piston of the toggle valve piston 7 has equal areas in its left and right chambers. Under the action of equal pressure and equal area in the left and right chambers, the left piston of the toggle valve piston 7 remains balanced and does not move the right piston. The limiting pressure of the pressure limiting part 8 of the toggle valve is 150 kPa. Before the control pressure CV is less than 150 kPa, the pressure limiting part 8 of the toggle valve remains open, and the left piston does not move.

[0052] Preferably, the right piston of the toggle valve piston 7 has unequal areas in its left and right chambers. After pressure is applied to the right chamber 704 of the right piston, the right piston of the toggle valve piston 7 moves to the left and in the opposite direction due to the unequal areas of the left and right chambers. More preferably, the working area of ​​the left chamber of the right piston of the toggle valve piston 7 is smaller than that of the right chamber. After pressure is applied to the right chamber 704 of the right piston, the right piston of the toggle valve piston 7 moves to the left and in the opposite direction due to the combined effect of a small area with high pressure in the left chamber and a large area with low pressure in the right chamber.

[0053] Due to the area difference of the right piston, the growth slope of the brake cylinder pressure BC does not coincide with the growth slope of the control pressure CV before the brake pipe pressure BP is reduced to 420 kPa. As the brake pipe pressure BP is reduced to 350 kPa, the control pressure CV increases, the pressure limiting part 8 of the kink valve closes, and the pressure at the left chamber 701 of the left piston is greater than the pressure at the right chamber 702 of the left piston. The left piston of the kink valve piston 7 pushes the right piston to the right, gradually eliminating the influence of the area difference of the right piston. The growth slope of the brake cylinder pressure BC and the growth slope of the control pressure CV finally coincide before BP is reduced to 380 kPa.

[0054] refer to Figure 5As shown, in the braking and pressure-holding position, as the CV' pressure increases, the pressure in the left chamber of the relay valve BC pressure piston 3 is balanced with the pressure in the right chamber and the pressure applied by the CV pressure piston 5. The balanced state of the relay valve BC pressure piston 3 causes the valve port of the CV' pressure application part 2 to close, the CV' pressure stops rising, and the relay valve is in the braking and pressure-holding state.

[0055] As the brake cylinder pressure BC increases, the pressure in the left chamber 701 of the left piston and the pressure in the left chamber 703 of the right piston are balanced with the pressure in the right chamber 702 of the left piston and the right chamber 704 of the right piston. The balanced state of the toggle valve piston 7 causes the valve port of the BC pressure action part 6 to close, the brake cylinder pressure BC stops rising, and the toggle valve is in the brake pressure holding position.

[0056] refer to Figure 6 As shown, in the relief position, the control pressure CV is discharged through the distribution valve and its pressure decreases. The effect of the control pressure CV on the CV pressure piston 5 weakens, and the effect of the CV pressure piston 5 on the relay valve BC pressure piston 3 weakens. The relay valve BC pressure piston 3 moves to the right, the valve port of the CV' pressure action part 2 closes, and the CV' pressure enters the empty weight adjustment part 4 through the internal air passage of the relay valve BC pressure piston 3, and then is discharged to the atmosphere through the CV' exhaust port EX2. After the control pressure CV decreases, the BC rise pressure limiting part 1 opens, and the pressure in the right chamber of the relay valve BC pressure piston 3 is discharged through the distribution valve.

[0057] As the control pressure CV decreases, the left chamber 701 of the left piston and the left chamber 703 of the right piston move to the left, the valve port of the BC pressure action part 6 closes, and the brake cylinder pressure BC is discharged to the atmosphere through the internal air passage of the BC pressure action part 6 and the brake cylinder pressure exhaust port EX2. After the control pressure CV decreases, the pressure limiting part 8 of the flex valve opens, and the pressure in the right chamber 702 of the left piston is discharged through the distribution valve.

[0058] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A relay valve with kinking characteristics, comprising a control pressure chamber and a relay valve BC pressure piston (3), characterized in that: It also includes a kink valve piston (7), which includes a left piston and a right piston. The control pressure chamber is connected to the left chamber (701) of the left piston and the left chamber (703) of the right piston of the kink valve piston (7), respectively. The left chamber (703) of the right piston is connected to the pressure limiting part (8) of the kink valve. The pressure limiting part (8) of the kink valve is connected to the right chamber (702) of the left piston of the kink valve piston (7). The relay valve BC pressure piston (3) is connected to the right chamber of the BC pressure action part (6). The left chamber of the BC pressure action part (6) is connected to the right chamber (704) of the right piston of the kink valve piston (7). The right chamber (704) of the right piston is connected to the pressure chamber of the brake cylinder.

2. The relay valve with kinking characteristics according to claim 1, characterized in that: It also includes the auxiliary air cylinder pressure chamber, the control pressure chamber is connected to the BC rise pressure limiting part (1), the BC rise pressure limiting part (1) is connected to the right chamber of the relay valve BC pressure piston (3), the auxiliary air cylinder pressure chamber is connected to the left chamber of the CV' pressure action part (2), the right chamber of the CV' pressure action part (2) is connected to the left chamber of the relay valve BC pressure piston (3), the left chamber of the relay valve BC pressure piston (3) is connected to the right chamber of the BC pressure action part (6), the control pressure chamber is connected to the CV pressure piston (5), and the other end of the CV pressure piston (5) is connected to the right end of the relay valve BC pressure piston (3).

3. The relay valve with kinking characteristics according to claim 1 or 2, characterized in that: The left and right chambers of the kink valve piston (7) have equal areas, while the left and right chambers of the right piston have unequal areas.

4. The relay valve with kinking characteristics according to claim 3, characterized in that: The working area of ​​the left chamber of the piston on the right side of the kink valve piston (7) is smaller than that of the right chamber.

5. A braking method for a relay valve with kinking characteristics, comprising a control pressure chamber and a relay valve BC pressure piston (3), characterized in that: In the braking position, the control pressure (CV) of the control pressure chamber enters the left chamber (701) of the left piston and the left chamber (703) of the right piston of the toggle valve piston (7) respectively. The pressure of the left chamber (703) of the right piston enters the right chamber (702) of the left piston of the toggle valve piston (7) through the pressure limiting part (8) of the toggle valve. The CV' pressure of the relay valve BC pressure piston (3) enters the right chamber of the BC pressure action part (6). The left piston of the toggle valve piston (7) does not move the right piston under the action of the pressure of the left and right chambers. The right piston of the toggle valve piston (7) moves to the right under the action of the pressure of the left chamber and pushes the valve port of the BC pressure action part (6) to open. The CV' pressure of the right chamber of the BC pressure action part (6) enters the brake cylinder pressure chamber and forms the brake cylinder pressure (BC) by passing through the valve port of the BC pressure action part (6), the left chamber of the BC pressure action part (6), and the right chamber (704) of the right piston of the toggle valve piston (7) in sequence, generating a jump pressure. After the right chamber (704) of the right piston is pressurized, the right piston of the kink valve piston (7) moves to the left and in the opposite direction under the pressure of the left and right chambers. Under no-load and intermediate load conditions, the valve port of the BC pressure action part (6) remains fully open under the action of the right piston. As the control pressure (CV) increases, the brake cylinder pressure (BC) continuously increases and performs braking. Under heavy load conditions, the valve port of the BC pressure action part (6) closes under the action of the right piston and begins to kink. As the control pressure (CV) increases, the pressure limiting part (8) of the kink valve closes. The pressure in the right chamber (702) of the left piston is constant. The pressure in the left chamber (701) of the left piston is greater than the pressure in the right chamber (702) of the left piston. The left piston of the kink valve piston (7) moves to the right under the action of the pressure of the left and right chambers. The left piston moving to the right pushes the valve port of the BC pressure action part (6) to open until it is fully open through the right piston, ending the kink. The brake cylinder pressure (BC) continuously increases and performs braking.

6. The braking method for the relay valve with kinking characteristics according to claim 5, characterized in that: The relay valve with kinking characteristics described in any one of claims 1 to 4 is used.

7. The braking method for a relay valve with kinking characteristics according to claim 5 or 6, characterized in that: It also includes the auxiliary air cylinder pressure chamber. In the initial inflation position, the auxiliary air cylinder pressure (AR) of the auxiliary air cylinder pressure chamber enters the left chamber of the CV' pressure action part (2). In the braking position, the control pressure (CV) of the control pressure chamber enters the right chamber of the relay valve BC pressure piston (3) through the BC rise pressure limiting part (1). The relay valve BC pressure piston (3) moves to the left under the pressure of the right chamber and pushes the valve port of the CV' pressure action part (2) to open. The auxiliary air cylinder pressure (AR) of the left chamber of the CV' pressure action part (2) enters the right chamber and forms the CV' pressure. The CV' pressure enters the relay valve BC pressure piston (3) and then enters the right chamber of the BC pressure action part (6). The control pressure (CV) of the control pressure chamber enters the CV pressure piston (5). As the control pressure (CV) increases, the BC rise pressure limiting part (1) closes, and the pressure in the right chamber of the relay valve BC pressure piston (3) remains constant. At the same time, the CV pressure piston (5) moves under the action of the control pressure (CV) and pushes the relay valve BC pressure piston (3) to the left. The valve port of the CV' pressure action part (2) opens wider, and the CV' pressure increases. In the brake pressure holding position, the CV' pressure increases, and the pressure in the left chamber of the relay valve BC pressure piston (3) is balanced with the pressure in the right chamber and the pressure acting on the CV pressure piston (5). The balanced relay valve BC pressure piston (3) causes the valve port of the CV' pressure acting part (2) to close, and the CV' pressure stops rising. The pressure in the left chamber (701) of the left piston and the pressure in the left chamber (703) of the right piston are balanced with the pressure in the right chamber (702) of the left piston and the right chamber (704) of the right piston. The balanced toggle valve piston (7) causes the valve port of the BC pressure acting part (6) to close, and the brake cylinder pressure (BC) stops rising. In the relief position, the control pressure (CV) is discharged through the distribution valve and the pressure decreases. The effect of the control pressure (CV) on the CV pressure piston (5) weakens, and the effect of the CV pressure piston (5) on the relay valve BC pressure piston (3) weakens. The relay valve BC pressure piston (3) moves to the right, the valve port of the CV' pressure action part (2) closes, and the CV' pressure is discharged to the atmosphere through the internal air passage of the relay valve BC pressure piston (3). The BC jump pressure limiting part (1) opens, and the pressure in the right chamber of the relay valve BC pressure piston (3) is discharged through the distribution valve. The pressure in the left chamber (701) of the left piston and the left chamber (703) of the right piston follows the decrease of the control pressure (CV). The toggle valve piston (7) moves to the left, the valve port of the BC pressure action part (6) closes, and the brake cylinder pressure (BC) is discharged to the atmosphere through the internal air passage of the BC pressure action part (6). The toggle valve pressure limiting part (8) opens, and the pressure in the right chamber (702) of the left piston is discharged through the distribution valve.

8. The braking method for a relay valve with kinking characteristics according to claim 5 or 6, characterized in that: At the initial inflation position, the empty weight signal control pressure (T) enters the empty weight signal control pressure chamber of the empty weight adjustment section (4). Different empty weight signal control pressures (T) correspond to different fulcrum positions of the CV pressure piston (5). The CV pressure piston (5) converts the control pressure (CV) into a force on the relay valve BC pressure piston (3) through a lever structure.

9. The braking method for a relay valve with kinking characteristics according to claim 5 or 6, characterized in that: In the braking position, the left and right chambers of the left piston of the kink valve piston (7) have equal areas. The left piston of the kink valve piston (7) remains balanced under the action of equal pressure and equal area in the left and right chambers and does not move the right piston. The left and right chambers of the right piston of the kink valve piston (7) have unequal areas. After the right chamber (704) of the right piston enters the pressure, the right piston of the kink valve piston (7) moves to the left and in the opposite direction under the action of unequal areas in the left and right chambers.

10. The braking method for the relay valve with kinking characteristics according to claim 9, characterized in that: In the braking position, the working area of ​​the left chamber of the right piston of the kink valve piston (7) is smaller than that of the right chamber. After the right chamber (704) of the right piston enters the pressure, the right piston of the kink valve piston (7) moves to the left in the opposite direction under the action of the small area of ​​the left chamber with large pressure and the large area of ​​the right chamber with small pressure.

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