Two-stage empty truck adjustment device for truck lever scale

Abstract

The application discloses a two-stage empty and heavy vehicle adjusting device for truck lever weighing, which comprises a lever weighing mechanism, wherein the lever weighing mechanism comprises a lever support, the middle part of a lever is rotatably installed on the lever support through a rotating shaft, one end of the lever is connected with a pull wire, a restoring spring is arranged between the other end of the lever and the lever support, and the other end of the lever is provided with a contact head. The new linear control two-stage device is developed and designed for the railway main line coal transportation line in China, and the empty and heavy adjusting device is only provided with two-stage adjustment of full empty and full heavy in view of the full empty-full heavy transportation characteristics of the railway coal transportation line. Compared with the traditional stepless empty and heavy vehicle adjusting device, the structure of the new linear control two-stage device is simplified and optimized, the lever weighing mechanism with simple structure is used to replace the traditional sensing valve, the related gas circuit and pipeline are greatly saved and simplified, the leakage points and the failure frequency are greatly reduced, and the safety and reliability of the system are improved.

Description

Technical Field

[0001] This invention belongs to the field of railway train braking control technology, specifically relating to a two-stage empty / loaded car adjustment device for freight car lever weighing. Background Technology

[0002] my country's main railway lines include dedicated coal transport lines from west to east. During transport, trains only have two states: fully loaded and fully empty. The entire train is equipped with a traditional stepless automatic empty / load adjustment device, which is complex in structure and has a high failure rate. Considering the characteristics of coal transport lines, this paper proposes to study a novel two-stage lever-weighing empty / load adjustment device. This device has only two adjustment functions: fully empty and fully loaded. Its structure is simplified, saving on crossbeam structures and related air circuits and pipelines, significantly reducing the frequency of leakage and failures, and greatly improving the system's reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a two-stage empty / loaded vehicle adjustment device for truck lever weighing, which solves the problems of complex structure and high failure rate of traditional stepless automatic empty / loaded vehicle adjustment devices.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A two-stage empty / loaded vehicle adjustment device for truck lever weighing includes a lever weighing mechanism, which includes a lever support. The middle part of the lever is rotatably mounted on the lever support via a rotating shaft. One end of the lever is connected to a pull wire, and a restoring spring is provided between the other end of the lever and the lever support. The other end of the lever is provided with a contact.

[0006] Furthermore, the lever support is provided with a pull wire holder, and the pull wire is threaded through the pull wire holder.

[0007] Furthermore, the lever bracket is provided with a screw, and the pull wire support is fixedly mounted on the screw.

[0008] Furthermore, the contact point is a omnidirectional ball.

[0009] Furthermore, the rotating shaft is fixed on the lever bracket, and a bushing is rotatably sleeved on the rotating shaft. The bushing passes through and is fixed on the lever. The lever is connected to the pull line by a pin.

[0010] Furthermore, the lever bracket is located above the vehicle side frame, and the cable is connected to the adjusting piston of the empty / loaded vehicle adjustment unit. During braking, the adjusting piston of the empty / loaded vehicle adjustment unit is driven by the air circuit signal, and the adjusting piston pulls the cable. The cable drives the lever to rotate. When the vehicle is in the loaded position, the contact point contacts the side frame and the lever stops rotating, so that the adjusting piston reaches the partially traveled loaded position. When the vehicle is in the empty position, the contact point does not contact the side frame, so that the lever stops rotating after the adjusting piston reaches the fully traveled empty position.

[0011] Furthermore, when the adjusting piston moves to the empty position, the connection between the Z1 and Z2 air circuits is cut off, while the Z2 air circuit is connected to the atmosphere. Only the Z1 air circuit acts on the lower part of the acting piston of the relay action section, making the area of ​​the lower part of the acting piston participating in pressure balance smaller than the area of ​​the upper part of the acting piston, thus outputting empty vehicle pressure during braking. When the adjusting piston moves to the loaded position, the Z1 and Z2 air circuits are connected, so that the Z1 and Z2 air circuits act together on the lower part of the acting piston, making the areas of the upper and lower parts of the acting piston participating in pressure balance equal, thus outputting loaded vehicle pressure during braking.

[0012] Furthermore, when the adjusting piston moves to the empty position, the internal passage of the adjusting piston shifts to cut off the connection between the z1 and z2 air passages, while the internal passage of the adjusting piston allows the z2 air passage to be connected to the atmosphere; when the adjusting piston moves to the loaded position, the internal passage of the adjusting piston shifts to connect the z1 and z2 air passages.

[0013] Furthermore, the z1 air circuit is connected to the brake output end of the distribution valve or brake valve, the f air circuit is connected to the auxiliary air cylinder, and the z air circuit is connected to the brake cylinder. When the z1 air circuit receives a brake signal from the distribution valve or brake valve and pressurizes, the pressure at the lower part of the actuating piston increases. The actuating piston drives the actuating piston rod and the actuating valve rod to move upward, causing the sealing ring of the actuating valve rod to disengage from the valve seat. The f air circuit and the z air circuit are connected, opening the passage from the auxiliary air cylinder to the brake cylinder and generating a braking effect. At the same time, the pressure at the upper part of the actuating piston rises. When the pressure at the upper part of the actuating piston rises to balance with the pressure at the lower part of the piston, the actuating valve rod, under the action of the valve rod spring, drives the sealing ring to push back onto the valve seat to generate a seal, cutting off the connection between the f air circuit and the z air circuit to close the passage from the auxiliary air cylinder to the brake cylinder. The braking process ends and enters the brake pressure holding phase.

[0014] Furthermore, when a relief signal is received from the distribution valve or brake valve and the Z1 air circuit is depressurized, the pressure at the lower part of the actuating piston decreases. At this time, the pressure at the upper part of the actuating piston is higher than the pressure at the lower part of the actuating piston. The actuating piston drives the actuating piston rod to move downward, causing the actuating piston rod to leave the sealing ring between the actuating valve rod and the actuating piston rod. Then, the Z air circuit and the central exhaust passage of the actuating piston rod are connected, opening the passage from the brake cylinder to the atmosphere. The pressurized air in the brake cylinder is discharged to the atmosphere through the central exhaust passage of the piston rod, generating a relief effect until the pressure at the upper and lower parts of the actuating piston is equal and reaches equilibrium. Under the action of the actuating diaphragm, the actuating piston returns to its previous state. When the pressure in the Z1 air circuit is reduced to zero, the Z air circuit is also reduced to zero, and the relief effect ends.

[0015] The beneficial effects of this invention are:

[0016] 1) Targeted: The new two-stage line control device is designed and developed specifically for coal transportation lines on my country's main railway lines. In view of the "all-empty-all-loaded" transportation characteristics of coal transportation lines, the empty-weight adjustment device is only set up with two-stage adjustment for all-empty and all-weight.

[0017] 2) Safety and reliability: Compared with the traditional stepless empty / loaded vehicle adjustment device, the new two-stage wire-controlled device has a simplified and optimized structure. It uses a simple lever weighing mechanism to replace the traditional sensor valve, which greatly saves and simplifies the related air circuits and pipelines, significantly reduces the frequency of leaks and failures, and improves the safety and reliability of the system.

[0018] 3) Economic efficiency: The new two-stage empty weight adjustment device saves on crossbeam structure and reduces vehicle manufacturing costs when newly manufactured and installed. When in use, it significantly reduces the system failure rate, reduces the huge maintenance costs incurred by the vehicle, and improves the utilization rate of the vehicle.

[0019] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention; 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 the present invention, 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 the present invention, and will not be exhaustively listed here. Attached Figure Description

[0020] Figure 1 This is a structural front view of the lever weighing mechanism of the present invention.

[0021] Figure 2 This is a structural side view of the lever weighing mechanism of the present invention.

[0022] Figure 3 This is a schematic diagram of the two-stage relay valve of the present invention.

[0023] In the diagram: 1-Lever weighing mechanism, 2-Empty / loaded vehicle adjustment section, 3-Relay action section, 4-Two-stage relay action valve; 11-Lever bracket, 12-Lever, 13-Shaft, 14-Pull cable, 15-Restoring spring, 16-Contact, 17-Shaft sleeve, 18-Pin, 19-Screw, 110-Pull cable support; 21-Relay valve body, 22-Adjusting valve cover, 23-Adjusting valve sleeve, 24-Adjusting piston, 25-Oil seal; 31-Relay valve cover, 32-Action piston, 33-Action diaphragm, 34-Action piston rod, 35-Action valve seat, 36-Action valve stem, 37-First sealing ring, 38-Second sealing ring, 39-Top cover, 310-Dust filter sleeve, 311-Valve stem spring. Detailed Implementation

[0024] The following non-limiting examples are used to illustrate the present invention.

[0025] Example 1:

[0026] refer to Figures 1-3As shown, a two-stage empty / loaded vehicle adjustment device for a freight car lever weighing system includes a lever weighing mechanism 1, an empty / loaded vehicle adjustment section 2, and a relay action section 3. The empty / loaded vehicle adjustment section 2 and the relay action section 3 together form a two-stage relay action valve 4. Because this device uses a cable to control and adjust the empty and loaded vehicles, it is also referred to as a cable-controlled two-stage empty / loaded vehicle adjustment device.

[0027] The lever weighing mechanism 1 is activated first when the train brakes, weighing the vehicle and feeding the weighing information back to the empty / loaded car adjustment unit 2, which then performs corresponding empty / loaded car adjustments. The empty / loaded car adjustment unit 2 adjusts the empty / loaded car based on the empty / loaded signal generated by the weighing mechanism. The relay unit 3 outputs braking force based on the empty / loaded car status of the empty / loaded car adjustment unit when the vehicle brakes.

[0028] The lever weighing mechanism 1 includes a lever bracket 11, a lever 12, a rotating shaft 13, a pull cable 14, a restoring spring 15, a contact 16, a bushing 17, a pin 18, a screw 19, and a pull cable support 110. The mechanism is fixedly installed via the lever bracket 11, ensuring that the entire assembly is positioned above the vehicle's side frame. The middle part of the lever 12 is rotatably mounted on the lever bracket 11 via the rotating shaft 13. Specifically, the rotating shaft 13 is fixed to the lever bracket 11, and a bushing 17 is rotatably sleeved on the rotating shaft 13. The bushing 17 passes through and is fixed to the lever 12, enabling the rotational movement of the lever 12.

[0029] One end of lever 12 is connected to pull wire 14, which is preferably a flexible steel wire. A pin 18 is fixed on lever 12, and pull wire 14 is wound and fixed on pin 18. Pull wire 14 connects to adjusting piston 24 of empty / loaded vehicle adjusting part 2. During braking, adjusting piston 24 drives lever 12 to rotate and swing through pull wire 14. A screw 19 is fixed on lever bracket 11, and pull wire support 110 is fixed on screw 19. Pull wire 14 passes through pull wire support 110, which provides guidance and support for pull wire 14, ensuring smooth movement of pull wire 14.

[0030] A restoring spring 15 is provided between the other end of the lever 12 and the lever support 11. A pin 18 is fixed on the lever 12. The restoring spring 15 is hooked on the pin 18. The restoring spring 15 provides elastic force to the lever 12. After the pulling force of the pull line 14 on the lever 12 disappears, the restoring spring 15 pulls the lever 12 to achieve reset.

[0031] The other end of the lever 12 is provided with a contact 16, which is a universal ball. When the vehicle is empty, the contact is designed to be 70mm away from the side frame vertically, while when the vehicle is loaded, it becomes 24mm. The contact 16 can rotate and slide freely while in contact with the side frame, so as to avoid damage to the lever caused by relative rotation and displacement between the side frame and the weighing mechanism when the vehicle is turning.

[0032] The lever bracket 11 is located above the vehicle side frame, and the cable 14 is connected to the adjusting piston 24 of the empty / loaded vehicle adjustment section 2. During braking, the adjusting piston 24 of the empty / loaded vehicle adjustment section 2 is driven by a pneumatic signal, pulling the cable 14. The cable 14 drives the lever 12 to rotate. When the vehicle is in the loaded position, the contact 16 contacts the side frame, and the lever 12 stops rotating, allowing the adjusting piston 24 to reach the partially traveled loaded position. When the vehicle is in the empty position, the contact 16 does not contact the side frame, allowing the adjusting piston 24 to reach the fully traveled empty position before the lever 12 stops rotating. When braking in the loaded position, the displacement of the cable is 9mm, and when braking in the empty position, the displacement is the full stroke of the piston, 18mm.

[0033] The empty / loaded vehicle adjustment unit 2 includes a relay valve body 21, an adjustment valve cover 22, an adjustment valve sleeve 23, an adjustment piston 24, and an oil seal 25. The adjustment valve sleeve 23 is located within the mounting groove of the relay valve body 21. The adjustment piston 24 slides left and right within the adjustment valve sleeve 23, enabling left and right piston movement. The adjustment valve cover 22 seals the adjustment valve sleeve 23. The right end of the adjustment piston 24 passes through the adjustment valve sleeve 23 and the adjustment valve cover 22 and connects to the pull cable 14. Each air passage is aligned with the internal passage on the adjustment piston 24 via the radial passage of the adjustment valve sleeve 23.

[0034] An O-ring is provided between the relay valve body 21 and the adjusting valve sleeve 23 for sealing and dust prevention. In addition to the O-ring sealing, an oil seal 25 is also provided at the front end of the adjusting piston 24 for sealing. The oil seal 25 contacts the adjusting piston 24 to further prevent dust, moisture and other impurities from entering.

[0035] The empty or loaded car adjustment unit 2 determines the empty or loaded car position by adjusting the movement distance of the piston. Taking into account the influence of the bolster spring vibration (the maximum amplitude of the bolster spring is about 4mm), when the leftward movement distance of the adjusting piston is less than 12mm, it is the loaded car position, and when the leftward movement distance exceeds 12mm, it is the empty car position.

[0036] When braking, the right side of the adjusting piston of the empty / loaded car adjustment unit 2 is driven to the left by the pressure of the air circuit z1, and the traction cable makes the lever rotate. When the car is in the loaded position, the lever contact is in contact with the side frame and stops rotating, so that the adjusting piston stays in the loaded position. When the car is in the empty position, the lever does not contact the side frame, so that the adjusting piston reaches the full stroke position.

[0037] When the adjusting piston 24 moves to the empty position, the internal passage of the adjusting piston 24 shifts, cutting off the connection between the z1 and z2 air passages. Simultaneously, the internal passage of the acting piston 32 connects the z2 air passage to the atmosphere, leaving only the z1 air passage acting on the lower part of the acting piston 32 in the relay acting section 3. This results in the lower area of ​​the acting piston participating in pressure balancing being smaller than the upper area, thus outputting empty vehicle pressure during braking. When the adjusting piston 24 moves to the loaded position, the internal passage of the adjusting piston 24 shifts again, connecting the z1 and z2 air passages. Both the z1 and z2 air passages then act together on the lower part of the acting piston 32, making the upper and lower areas of the acting piston participating in pressure balancing equal, thereby outputting loaded vehicle pressure during braking.

[0038] The relay action unit 3 includes a relay valve body 21, a relay valve cover 31, an action piston 32, an action diaphragm 33, an action piston rod 34, an action valve seat 35, an action valve stem 36, a first sealing ring 37, a second sealing ring 38, an upper cover 39, a dust filter sleeve 310, and a valve stem spring 311.

[0039] The relay valve body 21 and the relay valve cover 31 are connected to form an integral actuating valve. The actuating piston 32 and the actuating diaphragm 33 are located in the actuating cavity formed between the relay valve body 21 and the relay valve cover 31. The actuating diaphragm 33 is sandwiched between the valve body and the valve cover and is fixed at the outer edge of the actuating piston 32. The actuating piston 32 and the actuating diaphragm 33 divide the actuating cavity into upper and lower parts. The actuating piston 32 can slide up and down the relay valve body 21. The z1 air passage is connected to the first contact surface inside the actuating piston 32, and the z2 air passage is connected to the second contact surface outside the actuating piston 32. An actuating piston rod 34 is fixed at the center of the actuating piston 32. The actuating piston rod 34 can slide up and down the relay valve body 21 and the relay valve cover 31. At the same time, the actuating piston 32 has a central passage inside.

[0040] An actuating valve seat 35 is mounted on a relay valve cover 31. An actuating valve stem 36 slides up and down on the relay valve cover 31, with its middle portion passing through the actuating valve seat 35. A first sealing ring 37, which mates with the actuating valve seat 35, is located in the middle of the actuating valve stem 36. A second sealing ring 38, which mates with the actuating piston rod 34, is located at the bottom of the actuating valve stem 36. The middle portion of the actuating valve stem 36 is situated between the Z-channel and the F-channel, and the first sealing ring 37 mates with the actuating valve seat 35 to open or close the channels. The bottom of the actuating valve stem 36 is located within the Z-channel, and the second sealing ring 38 separates it from the central passage of the actuating piston rod 34. The upper cover 39 is connected to the upper part of the relay valve cover 31. The upper cover 39 limits the movement of the actuating valve seat 35 and also supports the valve stem spring 311. The valve stem spring 311 is located between the upper part of the actuating valve stem 36 and the upper cover 39, and provides the restoring force for the actuating valve stem 36.

[0041] The z1 air path connects to the brake output end of the distribution valve or brake valve, the f air path connects to the auxiliary air cylinder, and the z air path connects to the brake cylinder. Additionally, the z air path connects to the upper part of the actuating piston 32 via a constriction orifice. When a brake signal is received from the distribution valve or brake valve and the z1 air path pressurizes, the lower pressure of the actuating piston 32 increases. The actuating piston 32 drives the actuating piston rod 34 and the actuating valve rod 36 upwards, causing the sealing ring of the actuating valve rod 36 to disengage from the valve seat. The connection between the f and z air paths opens the passage from the auxiliary air cylinder to the brake cylinder, generating a braking effect. Simultaneously, the upper pressure of the actuating piston 32 rises. When the upper pressure of the actuating piston reaches equilibrium with the lower pressure, the actuating valve rod 36, under the action of the valve rod spring 311, drives the sealing ring to re-press onto the valve seat, creating a seal and cutting off the connection between the f and z air paths to close the passage from the auxiliary air cylinder to the brake cylinder. The braking process ends, and the brake pressure holding phase begins.

[0042] Intermediate action unit 3: During braking, when the empty / loaded car is adjusted to empty, the z2 air circuit is open to the atmosphere and does not participate in the braking action. When the z1 air circuit acts alone on the lower part of the action piston, when the upper and lower pressures of the action piston reach equilibrium, because the upper and lower piston areas participating in the braking action are unequal, the lower area is smaller than the upper area, the pressure of the brake cylinder will be less than z1, thus generating the empty car braking action; when the empty / loaded car is adjusted to loaded, the z1 and z2 air circuits are connected and act simultaneously on the lower part of the action piston, the upper and lower areas of the action piston participating in the braking action are equal, and when the upper and lower pressures of the action piston reach equilibrium, the pressure of the brake cylinder will be equal to that of the z1 air circuit, thus generating the loaded car braking action.

[0043] When a relief signal is received from the distribution valve or brake valve, the pressure in the Z1 air circuit decreases, and the pressure in the lower part of the actuating piston 32 decreases. At this time, the pressure in the upper part of the actuating piston is higher than the pressure in the lower part of the actuating piston. The actuating piston 32 drives the actuating piston rod 34 to move downward, so that the actuating piston rod 34 leaves the sealing ring between the actuating valve rod 36 and the actuating piston rod 34. Then the Z air circuit and the central exhaust passage of the actuating piston rod 34 are connected, opening the passage from the brake cylinder to the atmosphere. The pressure air in the brake cylinder is discharged to the atmosphere through the central exhaust passage of the piston rod to produce a relief effect until the pressure in the upper and lower parts of the actuating piston is equal and reaches equilibrium. Under the action of the actuating diaphragm 33, the actuating piston 32 returns to its previous state. When the pressure in the Z1 air circuit is reduced to zero, the Z air circuit is also reduced to zero, and the relief effect ends.

[0044] Key points of this invention:

[0045] 1) Two-stage wire-controlled lever weighing empty / loaded car adjustment device:

[0046] An innovative method for weighing using levers was invented, along with an innovative empty / loaded car adjustment device that uses levers for weighing. The device mainly consists of a lever weighing mechanism and a two-stage relay valve (empty / loaded car adjustment section and relay section). When it receives a braking or releasing signal from the air circuit of the distribution valve z1, it performs braking or releasing action.

[0047] 2) Lever weighing mechanism:

[0048] An innovative lever-based empty / load switching mechanism was invented. During braking, the lever position changes according to the empty / loaded vehicle status. When the vehicle is loaded, the lever rotates and stops after contacting the side frame, ensuring the displacement of the adjusting piston is less than 12mm. When the vehicle is empty, the lever does not contact the side frame, allowing the adjusting piston to reach its full stroke. The stroke at the empty / loaded vehicle switching point is set at 12mm; that is, a displacement of less than 12mm indicates a loaded vehicle position, and a displacement of more than 12mm indicates an empty vehicle position.

[0049] 3) Empty / loaded car adjustment mechanism:

[0050] An innovative empty / loaded car adjustment mechanism using lever weighing was invented. When braking, the piston is driven to the left by the braking pressure signal z1. The moving distance is controlled by the weighing mechanism. When the moving distance of the push rod is less than 12mm, the adjusting piston is in the loaded position. When the piston stroke is greater than 12mm, the adjusting piston moves to the empty position. When in the loaded position, the z1 and z2 passages are connected. When in the empty position, the z1 to z2 passage is cut off.

[0051] 4) Two-stage relay mechanism:

[0052] An innovative two-stage relay braking mechanism utilizing lever weighing was invented. Upon receiving the braking pre-control command from the distribution valve z1, the actuating piston moves upward, generating a two-stage braking effect with either empty or loaded pressure based on the empty / loaded status of the empty / loaded vehicle adjustment mechanism. When the vehicle is empty, only the z1 air passage below the actuating piston participates in the braking effect; when the vehicle is loaded, both the z1 and z2 air passages below the actuating piston participate in the braking effect simultaneously.

[0053] The foregoing basic examples and their further alternative examples of the present invention can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed by the present invention. In the present invention, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A two-stage empty / loaded vehicle adjustment device for truck lever weighing, comprising a lever weighing mechanism (1), characterized in that: The lever weighing mechanism (1) includes a lever support (11), the middle part of the lever (12) is rotatably mounted on the lever support (11) via a pivot (13), one end of the lever (12) is connected to a pull wire (14), a restoring spring (15) is provided between the other end of the lever (12) and the lever support (11), and a contact (16) is provided at the other end of the lever (12). The lever bracket (11) is located above the vehicle side frame. The pull cable (14) is connected to the adjusting piston (24) of the empty and loaded vehicle adjustment section (2). When braking, the adjusting piston (24) of the empty and loaded vehicle adjustment section (2) is driven by the air circuit signal. The adjusting piston (24) pulls the pull cable (14), and the pull cable (14) drives the lever (12) to rotate. When the vehicle is in the loaded position, the contact (16) contacts the side frame and the lever (12) stops rotating, so that the adjusting piston (24) reaches the partially traveled loaded position. When the vehicle is in the empty position, the contact (16) does not contact the side frame. After the adjusting piston (24) reaches the fully traveled empty position, the lever (12) stops rotating. The relay valve body (21) and the relay valve cover (31) are connected to form the entire action valve. The action piston (32) and the action diaphragm (33) are located in the action cavity formed between the relay valve body (21) and the relay valve cover (31). The action diaphragm (33) is sandwiched between the valve body and the valve cover, and the action diaphragm (33) is fixed at the outer edge of the action piston (32). The action cavity is divided into upper and lower parts by the action piston (32) and the action diaphragm (33). The action piston (32) slides up and down on the relay valve body (21). The z1 air passage is connected to the first contact surface inside the action piston (32), and the z2 air passage is connected to the second contact surface outside the action piston (32). When the adjusting piston (24) moves to the empty position, the connection between the z1 air path and the z2 air path is cut off, and the z2 air path is connected to the atmosphere. Only the z1 air path acts on the lower part of the action piston (32) of the relay action part (3), so that the lower part of the action piston participating in pressure balance is smaller than the upper part of the action piston, and the empty vehicle pressure is output during braking. When the adjusting piston (24) moves to the loaded position, the z1 air path and the z2 air path are connected, so that the z1 air path and the z2 air path act together on the lower part of the action piston (32), so that the upper and lower parts of the action piston participating in pressure balance are equal, and the loaded vehicle pressure is output during braking.

2. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 1, characterized in that: The lever support (11) is provided with a pull wire holder (110), and the pull wire (14) is threaded through the pull wire holder (110).

3. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 2, characterized in that: The lever bracket (11) is provided with a screw (19), and the pull wire support (110) is fixed on the screw (19).

4. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 1, characterized in that: The contact (16) is a universal ball.

5. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to any one of claims 1 to 4, characterized in that: The rotating shaft (13) is fixed on the lever bracket (11), and a bushing (17) is rotatably sleeved on the rotating shaft (13). The bushing (17) is fixed on the lever (12), and the lever (12) is connected to the pull line (14) through the pin (18).

6. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 1, characterized in that: When the adjusting piston (24) moves to the empty position, the internal passage of the adjusting piston (24) shifts to cut off the connection between the z1 air passage and the z2 air passage, and at the same time, the internal passage of the acting piston (32) makes the z2 air passage open to the atmosphere; when the adjusting piston (24) moves to the loaded position, the internal passage of the adjusting piston (24) shifts to make the z1 air passage and the z2 air passage open to each other.

7. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 1, characterized in that: A piston rod (34) is fixed at the center of the piston (32). The piston rod (34) slides on the relay valve body (21) and the relay valve cover (31). At the same time, a central passage is provided inside the piston (32). The valve seat (35) is provided on the relay valve cover (31). The valve rod (36) slides up and down on the relay valve cover (31). The middle part of the valve rod (36) passes through the valve seat (35). The middle part of the valve rod (36) is provided with a first sealing ring (37) that cooperates with the valve seat (35). The bottom of the valve rod (36) is provided with a second sealing ring (38) that cooperates with the piston rod (34). Located between the Z-channel and the F-channel, the first sealing ring (37) cooperates with the actuating valve seat (35) to realize the connection or closure of the channel; the bottom of the actuating valve stem (36) is located inside the Z-channel, and is separated between the Z-channel and the central passage of the actuating piston rod 34 by the second sealing ring (38); the upper cover (39) is connected to the upper part of the relay valve cover (31), and the upper cover (39) limits the actuating valve seat (35), and the upper cover (39) can also support the valve stem spring (311). The valve stem spring (311) is located between the upper part of the actuating valve stem (36) and the upper cover (39), and the valve stem spring (311) provides the restoring elastic force for the actuating valve stem (36); The z1 air path is connected to the brake output end of the distribution valve or brake valve, the f air path is connected to the auxiliary air cylinder, and the z air path is connected to the brake cylinder. When the z1 air path receives a brake signal from the distribution valve or brake valve and the pressure rises, the pressure at the lower part of the action piston (32) increases. The action piston (32) drives the action piston rod (34) and the action valve rod (36) to move upward, causing the sealing ring of the action valve rod (36) to disengage from the valve seat. The f air path and the z air path are connected, which opens the passage from the auxiliary air cylinder to the brake cylinder and generates a braking effect. At the same time, the pressure at the upper part of the action piston (32) rises. When the pressure at the upper part of the action piston rises to balance with the pressure at the lower part of the piston, the action valve rod (36) is driven by the valve rod spring (311) to push the sealing ring back onto the valve seat to generate a seal, cutting off the connection between the f air path and the z air path to close the passage from the auxiliary air cylinder to the brake cylinder. The braking process ends and enters the brake pressure holding stage.

8. The two-stage empty / loaded vehicle adjustment device for truck lever weighing according to claim 7, characterized in that: When a relief signal is received from the distribution valve or brake valve, the pressure in the z1 air circuit is reduced. At this time, the pressure in the upper part of the piston is higher than that in the lower part of the piston. The piston (32) drives the piston rod (34) to move down, so that the piston rod (34) leaves the sealing ring between the valve rod (36) and the piston rod (34). Then the z air circuit and the central exhaust passage of the piston rod (34) are connected to realize the passage from the brake cylinder to the atmosphere. The brake cylinder pressurized air is discharged to the atmosphere through the central exhaust passage of the piston rod to produce a relief effect until the pressure in the upper and lower parts of the piston is equal and reaches equilibrium. The piston (32) returns to its previous state under the action of the diaphragm (33). When the pressure in the z1 air circuit is reduced to zero, the pressure in the z air circuit is also reduced to zero, and the relief effect ends.

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