Test equipment for vehicle brakes

Abstract

The application provides a test device for a vehicle brake, comprising a constant-pressure control valve and a control device. The constant-pressure control valve comprises a gas containing device, a charging electromagnetic valve, a constant-pressure sensing element, a vehicle connecting pipe and a gas supply device. The gas containing device has a containing cavity, and a spacer is movably connected in the containing cavity. The spacer divides the containing cavity into a constant-pressure cavity and a brake cavity. The charging electromagnetic valve is connected with the constant-pressure cavity. The constant-pressure sensing element is connected with the constant-pressure cavity. One end of the vehicle connecting pipe is connected with the brake cavity, and the other end is connected with a vehicle brake. The gas supply device has a gas supply port, and a gas supply valve is arranged at the gas supply port. The spacer abuts against the gas supply valve. When the pressure in the constant-pressure cavity is greater than the pressure in the brake cavity, the gas supply valve is opened under the pushing of the spacer. When the pressure in the constant-pressure cavity is equal to the pressure in the brake cavity, the gas supply valve is closed. The control device is connected with the constant-pressure sensing element and the charging electromagnetic valve.

Description

Testing equipment for vehicle brakes Technical Field

[0001] This application relates to the field of testing technology, and in particular to a testing device for vehicle brakes. Background Technology

[0002] Currently, railway vehicles require specialized testing equipment for testing so that railway vehicle manufacturers, repair shops, and depots can inspect or accept the performance of vehicle brakes, thereby ensuring the manufacturing and maintenance quality of vehicle brakes.

[0003] In existing technologies, testing equipment commonly employs integrated valve islands, consisting of six solenoid valves. Depending on the test function, each solenoid valve is configured with a different orifice diameter based on its flow rate, connecting to the air supply pipe or the main brake pipe of a vehicle's brake system. During testing, different solenoid valves are opened to perform air filling or air depressurization / exhaust operations as needed. Installed pressure sensors collect pressure data in real time, acquiring various required test data. Once the specified pressure value is reached, the solenoid valves are closed. Because this device uses fixed orifice diameters to control the solenoid valves, the pressure control accuracy is not high, often failing to meet the specified requirements, necessitating repeated adjustments or retesting.

[0004] Therefore, how to provide a testing device with high pressure control accuracy has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a testing device for vehicle brakes.

[0006] To address the aforementioned technical problems, this application provides the following technical solutions:

[0007] The first aspect of this application provides a test apparatus for a vehicle brake, comprising:

[0008] A constant pressure control valve, comprising a gas containment device, an air filling solenoid valve, a constant pressure sensing element, a vehicle connecting pipe, and a gas supply device;

[0009] The gas containing device has a containing cavity, and a spacer is movably connected inside the containing cavity. In the initial state, the spacer divides the containing cavity into a constant pressure cavity and a braking cavity on an even basis. The direction from the center of the constant pressure cavity to the center of the braking cavity is the first direction.

[0010] The air-filling solenoid valve is connected to the pressure-regulating chamber to supply air to the pressure-regulating chamber and increase the pressure inside the pressure-regulating chamber.

[0011] The constant pressure sensing element is connected to the constant pressure cavity to sense the pressure value inside the constant pressure cavity;

[0012] One end of the vehicle connecting pipe is connected to the brake chamber, and the other end is connected to the vehicle brake.

[0013] The air supply device has an air supply port, and an air supply valve is provided at the air supply port. The air supply valve is located in the first direction of the spacer. In the initial state, the air supply valve is closed, one end of the spacer abuts against the air supply valve, and the air supply port is closed to the vehicle connecting pipe. When the pressure in the constant pressure chamber is greater than the pressure in the brake chamber, the spacer moves in the first direction to push the air supply valve open, and the air supply port is connected to the vehicle connecting pipe to deliver gas into the vehicle connecting pipe. When the constant pressure sensor senses that the pressure value in the constant pressure chamber reaches a first preset pressure, the air charging solenoid valve closes.

[0014] In some modified embodiments of the first aspect of this application, a control device is also included, which is connected to the constant pressure sensor and the air filling solenoid valve respectively, to receive the pressure value in the constant pressure chamber sensed by the constant pressure sensor, and to control the air filling solenoid valve according to the pressure value in the constant pressure chamber. When the pressure value in the constant pressure chamber reaches a first preset pressure, the control device closes the air filling solenoid valve.

[0015] In some modified embodiments of the first aspect of this application, the constant pressure control valve further includes:

[0016] A pressure regulating solenoid valve is connected to the constant pressure chamber to vent air from the constant pressure chamber and reduce the pressure inside the constant pressure chamber. The pressure regulating solenoid valve is also connected to the control device. The control device controls the pressure regulating solenoid valve according to the pressure value inside the constant pressure chamber sensed by the constant pressure sensor. When the pressure value inside the constant pressure chamber reaches a second preset pressure, the control device closes the pressure regulating solenoid valve.

[0017] An exhaust device is provided, which is connected to the vehicle connecting pipe. The exhaust device has an exhaust port and an exhaust valve is provided at the exhaust port. When the exhaust valve is open, the vehicle connecting pipe is connected to the exhaust device, and the pressure in the vehicle connecting pipe is discharged through the exhaust port of the exhaust device. When the exhaust valve is closed, the vehicle connecting pipe is closed from the exhaust device.

[0018] In the initial state, the air supply valve is closed, and the spacer passes through the exhaust valve and abuts against the air supply valve; when the pressure in the constant pressure chamber is less than the pressure in the braking chamber, the exhaust valve is connected to the spacer, and the spacer moves in the second direction to drive the exhaust valve to open.

[0019] In some modified embodiments of the first aspect of this application, the constant pressure control valve further includes:

[0020] A pressure-holding solenoid valve is provided, wherein the first end of the pressure-holding solenoid valve is connected to the constant pressure chamber and the second end is connected to the braking chamber. When the pressure-holding solenoid valve is opened, the constant pressure chamber and the braking chamber are connected.

[0021] In some modified embodiments of the first aspect of this application, the spacer includes:

[0022] A piston is disposed within the receiving cavity in a direction perpendicular to the first direction, thereby dividing the receiving cavity into a constant pressure cavity and a braking cavity;

[0023] A push rod is provided along a first direction, with its first end fixedly connected to the piston and its second end abutting against the air supply valve.

[0024] In some modified embodiments of the first aspect of this application, the exhaust valve is disposed between the gas containing device and the gas supply valve, and the exhaust valve is provided with a through hole adapted to the push rod along a first direction, and the push rod passes through the through hole and abuts against the gas supply valve;

[0025] The top rod is provided with a hook. When the top rod moves from the initial position along the second direction, the hook is locked to the exhaust valve, so as to drive the exhaust valve to move along the second direction, so that the exhaust valve opens relative to the exhaust port.

[0026] In some modified embodiments of the first aspect of this application, the constant pressure control valve further includes:

[0027] An air source sensor is connected to the air-filling solenoid valve and the control device to sense the air source pressure value entering the air-filling solenoid valve and send the air source pressure value to the control device.

[0028] When the air source pressure is at the third preset value, the control device controls the air-filling solenoid valve to supply air to the constant pressure chamber.

[0029] In some modified embodiments of the first aspect of this application, the control device includes:

[0030] A computer processing center having at least one button, which is pressed to receive a control command;

[0031] A control board, connected to the computer processing center, controls the air-filling solenoid valve to supply air to the constant pressure chamber or to exhaust air from the constant pressure chamber through the pressure-regulating solenoid valve according to the control instructions; and the control board is also connected to the constant pressure sensor, the air-filling solenoid valve, and the pressure-regulating solenoid valve to control the air supply rate or exhaust rate of the air-filling solenoid valve or the pressure-regulating solenoid valve according to the pressure of the constant pressure chamber sensed by the constant pressure sensor.

[0032] Some modified embodiments of the first aspect of this application also include:

[0033] A vehicle sensor, which is connected to the vehicle connecting pipe, is used to sense the pressure value connected to the vehicle connecting pipe;

[0034] The vehicle sensor is also connected to the control device to transmit the pressure value of the vehicle connection pipe to the control device.

[0035] In some modified embodiments of the first aspect of this application, the air-charging solenoid valve is a pulse width modulation air-charging solenoid valve;

[0036] The pressure regulating solenoid valve is a pulse width modulation pressure regulating solenoid valve.

[0037] In some modified embodiments of the first aspect of this application, the gas supply device further includes a body and an elastic element, the body is provided with the gas supply port, one end of the elastic element is connected to the gas supply valve, and the other end is connected to the body.

[0038] Initially, the elastic element is in a normal state;

[0039] The push rod pushes the air supply valve to move in the first direction. When the air supply valve is opened, the elastic element is in a stretched state.

[0040] When the push rod moves in the second direction, the elastic element drives the air supply valve back to its initial state.

[0041] Compared to existing technologies, the first aspect of this application provides a test device for a vehicle brake, including a constant pressure control valve. The constant pressure control valve includes a gas receiving device, a constant pressure sensing element, a charging solenoid valve, a vehicle connecting pipe, and a gas supply device. The gas receiving device has a receiving cavity, inside which a spacer is movably disposed. Initially, the spacer is located in the middle of the receiving cavity, dividing the cavity into a constant pressure cavity and a braking cavity. The constant pressure cavity and the braking cavity are separated by the spacer, forming two sealed spaces where gas cannot flow. The direction from the center of the constant pressure cavity to the center of the braking cavity is a first direction. The charging solenoid valve is connected to the constant pressure cavity and supplies gas to it to increase the pressure. As the pressure in the constant pressure cavity continuously increases, the spacer, under the pressure within the cavity, pushes the gas supply valve along the first direction, thereby increasing the gas supply. The valve moves in the first direction, causing the air supply valve to move from the air supply port, thereby opening the air supply valve. Gas in the air supply device can enter the vehicle connection pipe through the air supply port, thus transmitting the gas in the air supply device to the vehicle connection pipe. The vehicle connection pipe is connected to the brake chamber and the test vehicle, respectively, thus transmitting gas to the brake chamber and the vehicle brake to increase the pressure in the brake chamber and the vehicle brake. During the process of the air charging solenoid valve charging the constant pressure chamber, as the pressure in the constant pressure chamber continuously increases, the air supply valve opens wider and wider, and the air charging rate of the air supply device to the brake chamber and the test vehicle becomes faster and faster. During this process, the constant pressure sensor connected to the constant pressure chamber senses the pressure value in the constant pressure chamber in real time. When the pressure in the constant pressure chamber reaches the first preset pressure, the air charging solenoid valve stops charging the constant pressure chamber. Then, as the air supply device transmits more gas to the brake chamber through the vehicle connecting pipe, reducing the pressure difference between the brake chamber and the constant pressure chamber, the opening of the air supply valve gradually decreases until the pressure in the brake chamber is the same as that in the constant pressure chamber. At this point, the spacer returns to its initial position, the air supply valve closes, and the air supply device stops supplying gas to the vehicle connecting pipe. At this time, the pressure in the constant pressure chamber, the brake chamber, and the vehicle brake is the same, all being the first preset pressure.

[0042] Therefore, the vehicle brake testing equipment provided in this application achieves a first preset pressure by using a constant pressure chamber with the same pressure as the brake chamber. This results in high pressure control accuracy, avoiding the problem of poor pressure control accuracy in the prior art. This allows for better pressure testing of the vehicle brake, thus improving the accuracy of the test and ensuring the manufacturing and maintenance quality of the vehicle brake. Attached Figure Description

[0043] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:

[0044] Figure 1 is a schematic diagram of a test device for a vehicle brake provided in an embodiment of this application;

[0045] Explanation of icon numbers:

[0046] The system includes a constant pressure control valve 1, a gas containment device 11, a constant pressure chamber 111, a brake chamber 112, a spacer 12, a piston 121, a push rod 122, an air charging solenoid valve 13, a constant pressure sensing element 14, a vehicle connecting pipe 15, an air supply device 16, an air supply valve 161, a pressure regulating solenoid valve 17, an exhaust device 18, an exhaust valve 181, a pressure holding solenoid valve 19, an air source sensing element 20, a vehicle sensing element 22, and a first connecting pipe 23. Detailed Implementation

[0047] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] As shown in Figure 1, this application provides a test apparatus for a vehicle brake, comprising:

[0049] The constant pressure control valve 1 includes a gas containing device 11, an air charging solenoid valve 13, a constant pressure sensing element 14, a vehicle connecting pipe 15, and an air supply device 16.

[0050] The gas containing device 11 has a containing cavity, and a spacer 12 is movably connected in the containing cavity. In the initial state, the spacer 12 divides the containing cavity into a constant pressure cavity 111 and a braking cavity 112. The direction from the center of the constant pressure cavity 111 to the center of the braking cavity 112 is the first direction.

[0051] The air-filling solenoid valve 13 is connected to the pressure-regulating chamber 111 to supply air to the pressure-regulating chamber 111, thereby increasing the pressure inside the pressure-regulating chamber 111;

[0052] The constant pressure sensing element 14 is connected to the constant pressure cavity 111 to sense the pressure value inside the constant pressure cavity 111;

[0053] One end of the vehicle connecting pipe 15 is connected to the brake chamber 112, and the other end is connected to the vehicle brake.

[0054] The air supply device 16 has an air supply port, and an air supply valve 161 is provided at the air supply port. The air supply valve 161 is located in the first direction of the spacer 12. When the air supply valve 161 is open, the air supply port is connected to the vehicle connecting pipe 15 to deliver gas into the vehicle connecting pipe 15. When the air supply valve 161 is closed, the air supply port is closed from the vehicle connecting pipe 15. In the initial state, the air supply valve 161 is closed, and one end of the spacer 12 abuts against the air supply valve 161. When the pressure in the constant pressure chamber 111 is greater than the pressure in the brake chamber 112, the spacer 12 moves in the first direction to push the air supply valve 161 open.

[0055] A control device is connected to the constant pressure sensor 14 and the air filling solenoid valve 13 respectively, to receive the pressure value in the constant pressure chamber 111 sensed by the constant pressure sensor 14, and to control the air filling solenoid valve 13 according to the pressure value in the constant pressure chamber 111. When the pressure value in the constant pressure chamber 111 reaches a first preset pressure, the control device closes the air filling solenoid valve 13.

[0056] As shown in Figure 1, the vehicle brake testing equipment provided in this application includes a constant pressure control valve 1 and a control device. The constant pressure control valve 1 includes a gas receiving device 11, a constant pressure sensing element 14, an air charging solenoid valve 13, a vehicle connecting pipe 15, and an air supply device 16. The gas receiving device 11 has a receiving cavity, and a spacer 12 is movably disposed inside the receiving cavity. In the initial state, the spacer 12 is located in the middle position of the receiving cavity, and the spacer 12 divides the receiving cavity into a constant pressure cavity 111 and a braking cavity 112. The braking chamber 112 is divided into two sealed spaces by the spacer 12, preventing gas flow. The direction from the center of the pressure-regulating chamber 111 to the center of the braking chamber 112 is the first direction. The air-charging solenoid valve 13 is connected to the pressure-regulating chamber 111 and is used to supply air into the pressure-regulating chamber 111 to increase the pressure inside the pressure-regulating chamber 111. As the pressure in the pressure-regulating chamber 111 continues to rise, the spacer 12, under the action of the pressure inside the pressure-regulating chamber 111, pushes the air supply valve 161 against it along the first direction, causing the air supply valve 161 to move along the first direction. The movement causes the air supply valve 161 to move from the air supply port, thereby opening the air supply valve 161. Gas from the air supply device 16 can then enter the vehicle connection pipe 15 through the air supply port, transferring the gas from the air supply device 16 to the vehicle connection pipe 15. The vehicle connection pipe 15 is connected to both the brake chamber 112 and the test vehicle, thus transferring gas to both the brake chamber 112 and the vehicle brake, increasing the pressure within them. The air filling solenoid valve 13 then directs gas to the pressure regulating chamber. During the inflation process, as the pressure inside the constant pressure chamber 111 continuously increases, the air supply valve 161 opens wider and wider, and the air supply device 16 increases the inflation rate to the brake chamber 112 and the test vehicle. During this process, the constant pressure sensor 14 connected to the constant pressure chamber 111 senses the pressure value inside the constant pressure chamber 111 in real time and transmits the pressure value to the control device. When the pressure inside the constant pressure chamber 111 reaches the first preset pressure, the control device controls the air inflation solenoid valve 13 to stop inflating the constant pressure chamber 111. Then, as the air supply device 16 transmits more gas to the brake chamber 112 through the vehicle connecting pipe 15, reducing the pressure difference between the brake chamber 112 and the constant pressure chamber 111, the opening range of the air supply valve 161 also decreases until the pressure in the brake chamber 112 is the same as the pressure in the constant pressure chamber 111. At this point, the spacer 12 returns to its initial position, the air supply valve 161 closes, and the air supply device 16 stops supplying air to the vehicle connecting pipe 15. At this time, the pressure in the constant pressure chamber 111, the brake chamber 112, and the vehicle brake are all the same, which is the first preset pressure.

[0057] Therefore, the vehicle brake testing equipment provided in this application, by using the same pressure in the constant pressure chamber 111 and the brake chamber 112, enables the brake chamber 112 and the vehicle brake connected to the brake chamber 112 to reach the first preset pressure, thereby achieving high pressure control accuracy and avoiding the problem of poor pressure control accuracy in the prior art. This allows for better pressure testing of the vehicle brake, thus improving the accuracy of the test and ensuring the manufacturing and maintenance quality of the vehicle brake.

[0058] As shown in Figure 1, in this embodiment of the application, it further includes:

[0059] The constant pressure control valve 1 also includes:

[0060] A pressure regulating solenoid valve 17 is connected to the constant pressure chamber 111 to vent air from the constant pressure chamber 111, thereby reducing the pressure inside the constant pressure chamber 111. The pressure regulating solenoid valve 17 is also connected to the control device. The control device controls the pressure regulating solenoid valve 17 according to the pressure value inside the constant pressure chamber 111 sensed by the constant pressure sensor 14. When the pressure value inside the constant pressure chamber 111 reaches a second preset pressure, the control device closes the pressure regulating solenoid valve 17.

[0061] An exhaust device 18 is provided, which is connected to the vehicle connecting pipe 15. The exhaust device 18 has an exhaust port, and an exhaust valve 181 is provided at the exhaust port. When the exhaust valve 181 is open, the vehicle connecting pipe 15 is connected to the exhaust device 18, and the pressure in the vehicle connecting pipe 15 is discharged through the exhaust port of the exhaust device 18. When the exhaust valve 181 is closed, the vehicle connecting pipe 15 is closed from the exhaust device 18.

[0062] In the initial state, the air supply valve 161 is closed, and the spacer 12 passes through the exhaust valve 181 and abuts against the air supply valve 161. When the pressure in the constant pressure chamber 111 is less than the pressure in the braking chamber 112, the exhaust valve 181 is connected to the spacer 12, and the spacer 12 moves in the second direction to drive the exhaust valve to open.

[0063] In this embodiment, the constant pressure control valve 1 further includes a pressure regulating solenoid valve 17 and an exhaust device 18. The pressure regulating solenoid valve 17 is connected to the constant pressure chamber 111 and is used to discharge the gas in the constant pressure chamber 111, thereby achieving pressure reduction and exhaust in the constant pressure chamber 111. When the pressure regulating solenoid valve 17 performs pressure reduction and exhaust operation on the constant pressure chamber 111, the pressure in the constant pressure chamber 111 decreases, and the pressure in the braking chamber 112 is greater than the pressure in the constant pressure chamber 111. The spacer 12 moves along the second direction, and the volume of the constant pressure chamber 111 gradually decreases relative to the volume of the braking chamber 112. When the spacer 12 drives the exhaust valve 181 of the exhaust device 18 to move in the second direction, the exhaust device 18 is opened. As the pressure inside the constant pressure chamber 111 continuously decreases, the exhaust valve 181 opens wider and wider. The exhaust device 18 is connected to the vehicle connecting pipe 15, which is connected to the brake chamber 112 and the vehicle brake. Thus, when the exhaust port is open, the gas inside the brake chamber 112 and the vehicle brake can be discharged, thereby reducing the pressure inside the brake chamber 112 and the vehicle brake. During the pressure reduction and exhaust process in the constant pressure chamber 111, the constant pressure sensor 14 senses the pressure inside the constant pressure chamber 111 in real time. When the constant pressure sensor 14 senses that the pressure inside the constant pressure chamber 111 has dropped to the second preset pressure, the control device controls the pressure regulating solenoid valve 17 to close. After the pressure regulating solenoid valve 17 is closed, the brake chamber 112 and the vehicle brake will discharge more gas through the exhaust port, causing the pressure in the brake chamber 112 to gradually decrease. The spacer 12 drives the exhaust valve 181 to move in the first direction, so that the opening of the exhaust valve 181 becomes smaller and smaller. When the pressure in the brake chamber 112 is the same as the pressure in the constant pressure chamber 111, the spacer 12 returns to the initial position, the exhaust valve 181 closes, and the brake chamber 112 and the vehicle brake no longer discharge gas. At this time, the pressure in the constant pressure chamber 111, the brake chamber 112 and the vehicle brake are the same, all of which are the second preset pressure. Thus, the pressure in the vehicle brake is precisely regulated in the above way, so that the pressure in the vehicle brake can be accurately reduced to the second preset pressure. This results in high pressure control accuracy, which can better conduct pressure tests on the vehicle brake, thereby improving the accuracy of the test and ensuring the manufacturing and maintenance quality of the vehicle brake.

[0064] The first preset pressure is greater than the second preset pressure.

[0065] As shown in Figure 1, in this embodiment of the application, the constant pressure control valve 1 further includes:

[0066] Pressure holding solenoid valve 19, the first end of which is connected to the constant pressure chamber 111 and the second end of which is connected to the braking chamber 112;

[0067] The pressure-holding solenoid valve 19 is also connected to the control device, which controls the opening or closing of the pressure-holding solenoid valve 19. When the pressure-holding solenoid valve 19 is open, the pressure-regulating chamber 111 is connected to the braking chamber 112.

[0068] In this embodiment, the constant pressure control valve 1 further includes a pressure holding solenoid valve 19. The two ends of the pressure holding solenoid valve 19 are connected to the constant pressure chamber 111 and the brake chamber 112, respectively. The pressure holding solenoid valve 19 is also connected to the control device. After the constant pressure chamber 111 is vented and depressurized by the pressure regulating solenoid valve 17, the pressure in the constant pressure chamber 111 is the same as the pressure in the brake chamber 112. When the spacer 12 is in the initial position, the control device controls the pressure holding solenoid valve 19 to open, so that the constant pressure chamber 111 is connected to the brake chamber 112. This further ensures that the pressure in the constant pressure chamber 111 is the same as the pressure in the brake chamber 112. This ensures that the pressure in the vehicle brake connected by the vehicle connecting pipe 15 is the same as the pressure in the brake chamber 112 and the constant pressure chamber 111, further improving the precise adjustment of the pressure in the vehicle brake.

[0069] As shown in Figure 1, in this embodiment of the application, the spacer 12 includes:

[0070] Piston 121 is disposed in the receiving cavity in a direction perpendicular to the first direction to divide the receiving cavity into a constant pressure cavity 111 and a braking cavity 112;

[0071] A push rod 122 is arranged along a first direction. The first end of the push rod 122 is fixedly connected to the piston 121, and the second end abuts against the air supply valve 161.

[0072] In this embodiment, the spacer 12 includes a piston 121 and a push rod 122. The piston 121 is disposed in the middle of the receiving cavity along a direction perpendicular to the first direction, thereby dividing the receiving cavity into a constant pressure cavity 111 and a braking cavity 112. The push rod 122 extends along the first direction, with its first end connected to the piston 121 and its second end abutting against the air supply valve 161. In the initial state, the piston 121 evenly divides the receiving cavity formed by the gas receiving device 11 into the constant pressure cavity 111 and the braking cavity 112. The brake chamber 112 is defined as follows, with the direction from the center of the constant pressure chamber 111 to the center of the brake chamber 112 being the first direction. The gas containing device 11 is equipped with an exhaust device 18 and an air supply device 16 along this first direction. The first end of the push rod 122 is connected to the piston 121, and the second end of the push rod 122 passes through the air supply device 16 and abuts against the air supply valve 161. When the air pressure inside the constant pressure chamber 111 changes, pushing the piston 121 to move, it will cause the rod and the air supply valve 161 against which the rod abuts to move as well. When the pressure inside the constant pressure chamber 111 increases, under the pressure of the constant pressure chamber 111, the piston 121 will move along the first direction, thereby causing the push rod 122 and the air supply valve 161 to move along the first direction, thus opening the air supply port of the air supply device 16 to supply air to the vehicle connecting pipe 15, the brake chamber 112, and the vehicle brake. When the pressure in the constant pressure chamber 111 decreases, the piston 121 will drive the rod to move in the second direction, so that the second end of the push rod 122 no longer abuts against the air supply valve 161, so that the air supply valve 161 is no longer subjected to external force, and slowly returns to the initial position to block the air supply port.

[0073] In this embodiment of the application, the exhaust valve 181 is disposed between the gas containing device 11 and the gas supply valve 161, and the exhaust valve is provided with a through hole in the first direction that is adapted to the push rod 122, and the push rod 122 passes through the through hole and abuts against the gas supply valve 161.

[0074] The top rod 122 is provided with a hook. When the top rod 122 moves from the initial position along the second direction, the hook is locked to the exhaust valve 181 to drive the exhaust valve to move along the second direction so that the exhaust valve opens relative to the exhaust port.

[0075] In this embodiment, the exhaust valve is located between the gas receiving device 11 and the air supply valve 161, and the exhaust valve 181 is provided with a through hole in the first direction that is adapted to the push rod 122, so that the arrangement of the exhaust valve 181 will not affect the push rod 122's pushing of the air supply valve 161. The push rod 122 is also provided with a hook. When the push rod 122 moves from its initial position in the second direction, the hook on the push rod 122 will be fixed with the exhaust valve 181, so that the push rod 122 drives the exhaust valve 181 to move in the second direction to open the exhaust port, thereby allowing the vehicle connecting pipe 15, the brake chamber 112, and the vehicle brake to exhaust air.

[0076] As shown in Figure 1, in this embodiment of the application, the constant pressure control valve 1 further includes:

[0077] The air source sensor 20 is connected to the air charging solenoid valve 13 and the control device, and is used to sense the air source pressure value entering the air charging solenoid valve 13 and send the air source pressure value to the control device.

[0078] When the air source pressure is at the third preset value, the control device controls the air supply solenoid valve 13 to supply air into the constant pressure chamber 111.

[0079] In this embodiment, the constant pressure control valve 1 also includes an air source sensor 20, which is used to sense the air source pressure and send the air source pressure value to the control device. When the air source pressure is at a third preset value, it meets the specified requirements. The control device controls the air charging solenoid valve 13 to supply air to the constant pressure chamber 111. Thus, the air charging solenoid valve 13 can only supply air when the air source pressure reaches the third preset value, thereby achieving precise control of the pressure inside the vehicle brake and ensuring the quality of manufacturing and maintenance.

[0080] In this embodiment of the application, the control device includes:

[0081] A computer processing center having at least one button, which is pressed to receive a control command;

[0082] A control board, connected to the computer processing center, controls the air-filling solenoid valve 13 to supply air to the constant pressure chamber 111 or to exhaust air from the constant pressure chamber 111 through the pressure-regulating solenoid valve 17 according to the control commands; and the control board is also connected to the constant pressure sensor 14, the air-filling solenoid valve 13 and the pressure-regulating solenoid valve 17 to control the air supply rate or exhaust rate of the air-filling solenoid valve 13 or the pressure-regulating solenoid valve 17 according to the pressure of the constant pressure chamber 111 sensed by the constant pressure sensor 14.

[0083] In this embodiment, the control device includes a computer processing center and a control board. The computer processing center includes multiple buttons, such as a start button, a brake sensitivity test button, a brake release sensitivity test button, a brake stability test button, and an end button. Control commands are sent by pressing any button. The control board is connected to the computer processing center, receives the control commands sent by the computer processing center, and performs different actions according to different control commands. After receiving the control command, the control board controls the constant pressure control valve 1 to supply air to the constant pressure chamber 111 through the air charging solenoid valve 13 or to exhaust air from the constant pressure chamber 111 through the pressure regulating solenoid valve 17, thereby realizing the supply or exhaust of air in the constant pressure chamber 111, and thus realizing the charging or venting of air in the vehicle brake. Furthermore, during the process of supplying air to the constant pressure chamber 111 via the air-inflating solenoid valve 13, or venting the constant pressure chamber 111 via the pressure-regulating solenoid valve 17, the constant pressure sensing element 14 transmits the real-time pressure value sensed within the constant pressure chamber 111 to the control device. The control device performs an air-inflating operation within the constant pressure chamber 111. When the pressure value within the constant pressure chamber 111 approaches the first preset pressure, the air-inflating solenoid valve 13 slows down its air-inflating speed, reducing the amount of air inflated per unit time. This ensures that the constant pressure chamber 111 reaches only the first preset pressure after inflation, and does not exceed the first preset pressure, thereby improving pressure control accuracy. Similarly, during the venting operation within the constant pressure chamber 111, when the pressure value within the constant pressure chamber 111 approaches the second preset pressure, the control device slows down the venting speed of the pressure-regulating solenoid valve, reducing the amount of air vented per unit time. This ensures that the constant pressure chamber 111 reaches only the second preset pressure after inflation, and does not fall below the second preset pressure, thereby improving pressure control accuracy.

[0084] As shown in Figure 1, in this embodiment of the application, it further includes: a vehicle sensor 22, which is connected to the vehicle connecting pipe 15 and is used to sense the pressure value connected to the vehicle connecting pipe 15.

[0085] The vehicle sensor 22 is also connected to the control device to transmit the pressure value connected to the vehicle connection pipe 15 to the control device.

[0086] In this embodiment, the vehicle brake testing equipment also includes a vehicle sensor 22. The vehicle sensor is connected to the vehicle connecting pipe 15 and is used to sense the pressure value inside the vehicle connecting pipe 15. The vehicle connecting pipe 15 is connected to the vehicle brake, and the pressure value inside the vehicle connecting pipe 15 is basically equal to the pressure value inside the vehicle brake. Thus, the pressure value inside the vehicle brake can be determined based on the pressure value inside the vehicle connecting pipe 15, and the pressure value inside the vehicle connecting pipe 15 is transmitted to the control device to obtain the test data of the vehicle brake. This facilitates the control device to obtain the test results of the vehicle brake based on the pressure value connected to the vehicle connecting pipe 15.

[0087] In this embodiment, the air-filling solenoid valve 13 is a pulse width modulation air-filling solenoid valve 13;

[0088] The pressure regulating solenoid valve 17 is a pulse width modulation pressure regulating solenoid valve 17.

[0089] In this embodiment, the pulse width modulation (PWM) air-filling solenoid valve 13 and the PWM pressure-regulating solenoid valve 17 have the advantages of simple control, flexibility, and good dynamic response. When the constant pressure chamber 111 needs to be filled to the first preset pressure, the PWM air-filling solenoid valve 13 can fill it quickly and instantly, and the filling speed slows down when approaching the first preset pressure. When the constant pressure chamber 111 needs to be lowered to the second preset pressure, the PWM pressure-regulating solenoid valve can exhaust the pressure quickly and instantly, and the exhaust speed slows down when approaching the second preset pressure, thus achieving better pressure control accuracy.

[0090] In this embodiment, the constant pressure sensing element 14 is a constant pressure sensor, the wind source sensing element 20 is a wind source sensor, and the vehicle sensing element 22 is a vehicle sensor.

[0091] As shown in Figure 1, in this embodiment of the application, it further includes:

[0092] The first connecting pipe 23 is connected at one end to the vehicle connecting pipe 15 and at the other end to the brake cavity 112.

[0093] In this embodiment, the vehicle connecting pipe 15 is connected to the brake chamber 112 via the first connecting pipe 23, thereby allowing the gas in the vehicle connecting pipe 15 to be filled into the brake chamber 112, or allowing the gas in the brake chamber 112 to be discharged through the vehicle connecting pipe 15.

[0094] In this embodiment of the application, the gas supply device 16 further includes a body and an elastic element. The body is provided with the gas supply port, and one end of the elastic element is connected to the gas supply valve 161, and the other end is connected to the body.

[0095] Initially, the elastic element is in a normal state;

[0096] The push rod 122 pushes the air supply valve 161 to move in the first direction. When the air supply valve 161 is opened, the elastic element is in a stretched state.

[0097] When the push rod 122 moves in the second direction, the elastic element drives the air supply valve 161 back to its initial state.

[0098] In this embodiment, the air supply device 16 includes a body / air supply valve 161 and an elastic element. The body is provided with an air supply port, and the air supply port is provided with an air supply valve 161. One end of the elastic element is connected to the air supply valve 161, and the other end is connected to the body. In the initial state, piston 121 is located in the middle position of gas receiving device 11, dividing the constant pressure chamber 111 and brake chamber 112 equally. At this time, the second end of push rod 122 connected to piston 121 abuts against air supply valve 161. After air is supplied to constant pressure chamber 111, the pressure in constant pressure chamber 111 increases. Under the action of pressure, piston 121 drives push rod 122 to move in the first direction, thereby moving air supply valve 161 away from air supply port, so that air supply port can be opened to supply air to vehicle connecting pipe 15 and constant pressure chamber 111. When constant pressure chamber 111 is no longer supplied with air, constant pressure chamber 111 continues to increase pressure. At this time, piston 121 will move in the second direction, so that piston 121 returns to the middle position. During this process, the second end of push rod 122 no longer abuts against air supply valve 161. Air supply valve 161 will return to the initial position under the action of elastic element, thereby ensuring the return of position of air supply valve 161.

[0099] The elastic element is a spring.

[0100] In this embodiment, when conducting a pressure test on the vehicle brake using the vehicle brake testing equipment, the testing equipment is powered on, and the touchscreen of the computer processing center displays the basic information of the test vehicle. After the test personnel input the vehicle model, vehicle number, brake model, and brake cylinder specifications, wireless pressure sensors are installed on the auxiliary air cylinder and the brake cylinder of the test vehicle's brake system. A wireless length measuring sensor is installed at the brake cylinder's caliper extension. After connecting the vehicle connection pipe 15 of the vehicle brake testing equipment to the hose connector of the test vehicle's brake system, the "Start" button for "Air Brake Test" on the computer processing center is clicked. After receiving the command, the control board collects pressure data from the air source sensor 20 via the constant pressure control valve 1. If the data meets the specified requirements, it controls the air-charging solenoid valve 13 to rapidly charge air into the constant pressure chamber 111. As the pressure inside the chamber continuously increases, the piston 121 pushes the push rod 122 in the first direction, gradually opening the air supply valve 161. The air source from the air supply port of the air supply device 16 enters the vehicle connecting pipe 15 through the opened air supply valve 161, and then charges the vehicle brakes of the test vehicle through the connected hose connector. As the pressure inside the constant pressure chamber 111 continuously increases, the air supply valve 161 opens wider and wider, and the charging rate increases rapidly. The system collects pressure data from the constant pressure sensor 14 and the vehicle connection pipe 15 from the vehicle sensor 22 in real time. It also receives pressure data from the wireless auxiliary air cylinder pressure sensor installed on the test vehicle via a wireless communication module and uploads it to the computer processing center in real time. When the pressure data from the constant pressure sensor 14 approaches the first preset pressure, the control board controls the air supply solenoid valve 13 to gradually reduce the air supply. Once the first preset pressure is reached, the air supply solenoid valve 13 is closed. As the pressure in the auxiliary air cylinder of the vehicle's brake system continuously increases, the pressure in the brake chamber 112 connected to the vehicle connection pipe 15 also continuously increases under the action of the first connection pipe 23. A continuous thrust is applied to the spacer 12 in the second direction, causing the push rod 122 to move in the second direction. The air supply valve 161 continuously reduces the gap between itself and the air supply port, thus decreasing the air supply volume. As the pressure in the vehicle's auxiliary air cylinder continuously increases, when it reaches the set pressure value, and the pressure in the set pressure chamber 111 equals the pressure in the brake chamber 112, the air supply valve 161 closes. The control board collects pressure data from the set pressure sensor 14 and the vehicle sensor 22 in real time, and receives pressure data from the wireless auxiliary air cylinder pressure sensor installed on the test vehicle via the wireless communication module. This data is then uploaded in real time to the microcomputer data processing center, completing the air filling operation.

[0101] In this embodiment, the tester clicks the "Brake Sensitivity Test" button in the "Air Brake Test" test project on the computer processing center touchscreen. The computer processing center issues a test command. Upon receiving the command, the control board controls the pressure regulating solenoid valve 17 via the constant pressure control valve 1 to reduce and release the pressure in the constant pressure chamber 111. The pressure in the second direction of the spacer 12 decreases, and the pressure in the brake chamber 112 becomes higher than that in the constant pressure chamber 111. The piston 121 drives the push rod 12220 to move in the second direction, and the push rod 122 opens the exhaust valve 181, releasing the pressure in the vehicle connecting pipe 15 through the exhaust valve 181. The pressure reduction is 40 kPa or 50 kPa depending on the brake model of the test vehicle. The control board collects the pressure data from the constant pressure sensor 14 in real time. When the pressure reduction approaches the constant pressure value, the control board controls the pressure regulating solenoid valve 17 to gradually reduce the exhaust volume. When the constant pressure value is reached, the pressure regulating solenoid valve 17 closes. When the pressure at both ends of the piston 121 gradually becomes equal, the exhaust valve 181 closes. The control board drives the pressure-holding solenoid valve 19 to open, at which time the pressure-regulating chamber 111 is connected to the brake chamber 112. The pressure is maintained for one minute, and the brake does not release. The control board collects the pressure data of the pressure-regulating sensor 14 and the pressure data of the vehicle sensor 22 in real time, and receives the pressure data of the wireless auxiliary air cylinder and the wireless pressure sensor installed on the test vehicle through the wireless communication module, and uploads it to the computer processing center in real time. The operation is completed.

[0102] In this embodiment, the tester clicks the "Relief Sensitivity Test" button in the "Air Brake Test" project on the computer processing center's touchscreen. The microcomputer data processing center issues a test command. Upon receiving the command, the control board controls the air-charging solenoid valve 13 to charge air into the constant pressure chamber 111 in a slow-charging mode via the constant pressure control valve 1. As the pressure inside the chamber continuously increases, the piston 121 pushes the push rod 122 to move in the first direction, opening the air supply valve 161. The air source from the air supply port enters the vehicle connecting pipe 15 through the opened air supply valve 161 and charges the vehicle brake of the test vehicle through the connected hose connector. The control board collects the pressure data of the constant pressure sensor 14, the vehicle sensor 22, and the pressure data of the wireless auxiliary air cylinder pressure sensor installed on the test vehicle in real time and uploads the data in real time. When the pressure data of the constant pressure sensor 14 reaches the set constant pressure value, the control board controls the air-charging solenoid valve 13 to close. When the pressure inside the constant pressure chamber 111 is equal to the pressure inside the braking chamber 112, the air filling is completed within 45 seconds.

[0103] In this embodiment, the tester clicks the "Brake Stability Test" button in the "Air Brake Test" test project on the touch screen of the computer processing center. The microcomputer data processing center issues a test command. After receiving the command, the control board controls the pressure regulating solenoid valve 17 through the constant pressure control valve 1 to reduce the pressure in the constant pressure chamber 111. Depending on the brake model of the test vehicle, the pressure reduction is 200 kPa, 170 kPa, or 140 kPa. The pressure in the second direction of the piston 121 decreases, and the pressure in the brake chamber 112 in the first direction is higher than that in the constant pressure chamber 111 in the second direction. The piston 121 drives the push rod 122 to move in the second direction and opens the exhaust valve 181. The pressure in the vehicle connecting pipe 15 and the brake chamber 112 is discharged to the outside through the exhaust valve 181. The control board collects the pressure data of the constant pressure sensor 14 in real time. When the pressure reduction is detected to be close to the constant pressure value, the control board controls the pressure regulating solenoid valve 17 to gradually reduce the exhaust volume. When the constant pressure value is reached, the pressure regulating solenoid valve 17 is closed. When the pressure at both ends of piston 121 gradually becomes equal, exhaust valve 181 closes. Once the pressure stabilizes, the control board drives the pressure-holding solenoid valve 19 to open, connecting the pressure-regulating chamber 111 to the brake chamber 112. Pressure is maintained for one minute; if leakage between the vehicle's brake lines does not exceed the limit, the brakes will not release. The control board collects pressure data from the vehicle's sensing element 22 and the wireless brake cylinder pressure sensor, as well as length measurement data from the wireless brake cylinder brake stroke length measuring sensor, and uploads this data in real time. The operation is then complete. The test personnel close the angle plug at one end of the brake main pipe connected to the single-vehicle tester on the test vehicle.

[0104] In this embodiment, the tester clicks the "End Operation" button on the "Air Brake Test" test project on the computer processing center touchscreen. The computer processing center issues an "End Operation" command and saves the experimental data. After receiving the command, the control board controls the pressure regulating solenoid valve 17 through the constant pressure control valve 1 to empty the pressure in the constant pressure chamber 111, and monitors in real time whether the constant pressure sensor 14 and the vehicle sensor 22 are zero. After completion, the tester disconnects the hose connector of the vehicle connection pipe 15 of the vehicle brake test equipment from the hose connector of the brake main pipe of the test vehicle, removes and recycles the wireless auxiliary air cylinder pressure sensor, wireless brake cylinder pressure sensor, and wireless brake cylinder stroke length measurement sensor installed on the test vehicle, and shuts down the equipment.

[0105] This application provides a test device for a vehicle brake, including a constant pressure control valve and a control device. The constant pressure control valve includes a gas receiving device, a constant pressure sensing element, a charging solenoid valve, a vehicle connecting pipe, and a gas supply device. The gas receiving device has a receiving cavity, inside which a spacer is movably disposed. Initially, the spacer is located in the middle of the receiving cavity, dividing the receiving cavity into a constant pressure cavity and a braking cavity. The constant pressure cavity and the braking cavity are separated by the spacer, forming two sealed spaces where gas cannot flow. The direction from the center of the constant pressure cavity to the center of the braking cavity is the first direction. The charging solenoid valve is connected to the constant pressure cavity and is used to supply gas into the constant pressure cavity to increase the pressure inside the constant pressure cavity. As the pressure in the constant pressure cavity continuously increases, the spacer, under the action of the pressure inside the constant pressure cavity, pushes the gas supply valve along the first direction, causing the gas supply valve to move along the first direction, thereby... This causes the air supply valve to move from the air supply port, thereby opening the air supply valve. Gas from the air supply device can then enter the vehicle connection pipe through the air supply port, thus transferring the gas from the air supply device to the vehicle connection pipe. The vehicle connection pipe is connected to the brake chamber and the test vehicle, respectively, thereby transferring gas to the brake chamber and the vehicle brake to increase the pressure in the brake chamber and the vehicle brake. During the process of the air charging solenoid valve charging the constant pressure chamber, as the pressure in the constant pressure chamber continuously increases, the air supply valve opens wider and wider, and the air charging rate of the air supply device to the brake chamber and the test vehicle becomes faster and faster. During this process, the constant pressure sensor connected to the constant pressure chamber senses the pressure value in the constant pressure chamber in real time and transmits the pressure value to the control device. When the pressure in the constant pressure chamber reaches the first preset pressure, the control device controls the air charging solenoid valve to stop charging the constant pressure chamber. Then, as the air supply device transmits more gas to the brake chamber through the vehicle connecting pipe, reducing the pressure difference between the brake chamber and the constant pressure chamber, the opening of the air supply valve gradually decreases until the pressure in the brake chamber is the same as that in the constant pressure chamber. At this point, the spacer returns to its initial position, the air supply valve closes, and the air supply device stops supplying gas to the vehicle connecting pipe. At this time, the pressure in the constant pressure chamber, the brake chamber, and the vehicle brake is the same, all being the first preset pressure.

[0106] Therefore, the vehicle brake testing equipment provided in this application achieves a first preset pressure by using a constant pressure chamber with the same pressure as the brake chamber. This results in high pressure control accuracy, avoiding the problem of poor pressure control accuracy in the prior art. This allows for better pressure testing of the vehicle brake, thus improving the accuracy of the test and ensuring the manufacturing and maintenance quality of the vehicle brake.

[0107] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A testing device for vehicle brakes, characterized in that, include: A constant pressure control valve includes a gas receiving device, an air-charging solenoid valve, a constant pressure sensing element, a vehicle connecting pipe, and an air supply device. The gas receiving device has a receiving cavity, within which a spacer is movably connected. Initially, the spacer divides the receiving cavity into a constant pressure cavity and a braking cavity, with the direction from the center of the constant pressure cavity to the center of the braking cavity being a first direction. The air-charging solenoid valve is connected to the constant pressure cavity to supply air to increase the pressure within it. The constant pressure sensing element is connected to... The constant pressure chamber is connected for sensing the pressure value within it; one end of the vehicle connecting pipe is connected to the brake chamber, and the other end is connected to the vehicle brake; the air supply device has an air supply port, and an air supply valve is provided at the air supply port, the air supply valve being positioned in the first direction of the spacer; initially, the air supply valve is closed, one end of the spacer abuts against the air supply valve, and the air supply port is closed to the vehicle connecting pipe; when the pressure within the constant pressure chamber is greater than the pressure within the brake chamber, the spacer moves along the first direction. The device is activated to open the air supply valve, connecting the air supply port to the vehicle connection pipe to deliver gas into the vehicle connection pipe. When the constant pressure sensor detects that the pressure value in the constant pressure chamber reaches the first preset pressure, the air charging solenoid valve closes. As the air supply device transmits gas to the brake chamber through the vehicle connection pipe, and the pressure difference between the brake chamber and the constant pressure chamber decreases, the opening of the air supply valve also decreases until the pressure in the brake chamber is the same as the pressure in the constant pressure chamber. At this point, the spacer returns to its initial position, the air supply valve closes, and the air supply device no longer supplies gas to the vehicle connection pipe. The pressure in the constant pressure chamber, the brake chamber, and the vehicle brake is the same, all being the first preset pressure. The spacer includes: a piston, which is disposed in the receiving cavity in a direction perpendicular to the first direction to divide the receiving cavity into a constant pressure chamber and a brake chamber; and a push rod, which is disposed in the first direction, with its first end fixedly connected to the piston and its second end abutting against the air supply valve.

2. The testing equipment for vehicle brakes according to claim 1, characterized in that, Also includes: A control device is connected to the constant pressure sensor and the air filling solenoid valve respectively, so as to receive the pressure value in the constant pressure chamber sensed by the constant pressure sensor, and control the air filling solenoid valve according to the pressure value in the constant pressure chamber. When the pressure value in the constant pressure chamber reaches a first preset pressure, the control device closes the air filling solenoid valve.

3. The testing equipment for vehicle brakes according to claim 2, characterized in that, The constant pressure control valve further includes: a pressure regulating solenoid valve, which is connected to the constant pressure chamber to vent air from the constant pressure chamber and reduce the pressure within it. The pressure regulating solenoid valve is also connected to the control device, which controls the pressure regulating solenoid valve based on the pressure value sensed by the constant pressure sensor. When the pressure value within the constant pressure chamber reaches a second preset pressure, the control device closes the pressure regulating solenoid valve. An exhaust device is also included, connected to the vehicle connection pipe and having an exhaust port. An exhaust valve is provided at the exhaust port; when the exhaust valve is open, the vehicle connecting pipe is connected to the exhaust device, and the pressure in the vehicle connecting pipe is discharged through the exhaust port of the exhaust device; when the exhaust valve is closed, the vehicle connecting pipe is closed to the exhaust device; in the initial state, the air supply valve is closed, and the spacer passes through the exhaust valve and abuts against the air supply valve; when the pressure in the constant pressure chamber is less than the pressure in the brake chamber, the exhaust valve is connected to the spacer, and the spacer moves in the second direction to drive the exhaust valve to open.

4. The testing equipment for vehicle brakes according to claim 3, characterized in that, The constant pressure control valve further includes a pressure holding solenoid valve, the first end of which is connected to the constant pressure chamber and the second end of which is connected to the brake chamber. When the pressure holding solenoid valve is opened, the constant pressure chamber and the brake chamber are in communication.

5. The testing equipment for vehicle brakes according to claim 3, characterized in that, The exhaust valve is disposed between the gas containing device and the gas supply valve. The exhaust valve is provided with a through hole in the first direction that is adapted to the push rod. The push rod passes through the through hole and abuts against the gas supply valve. The push rod is provided with a hook. When the push rod moves from the initial position in the second direction, the hook is locked with the exhaust valve to drive the exhaust valve to move in the second direction so that the exhaust valve opens relative to the exhaust port.

6. The testing equipment for vehicle brakes according to claim 3, characterized in that, The constant pressure control valve further includes: an air source sensor, which is connected to the air charging solenoid valve and the control device, for sensing the air source pressure value entering the air charging solenoid valve and sending the air source pressure value to the control device; when the air source pressure value is a third preset value, the control device controls the air charging solenoid valve to supply air to the constant pressure chamber.

7. The testing equipment for vehicle brakes according to claim 6, characterized in that, The control device includes: a computer processing center having at least one button, pressing the button to receive control commands; a control board connected to the computer processing center to control the air-filling solenoid valve to supply air to the constant pressure chamber or to exhaust air from the constant pressure chamber through the pressure-regulating solenoid valve according to the control commands; and the control board is also connected to the constant pressure sensor, the air-filling solenoid valve, and the pressure-regulating solenoid valve to control the air supply rate or exhaust rate of the air-filling solenoid valve or the pressure-regulating solenoid valve according to the pressure of the constant pressure chamber sensed by the constant pressure sensor.

8. The testing equipment for vehicle brakes according to claim 6, characterized in that, It also includes: a vehicle sensor connected to the vehicle connecting pipe for sensing the pressure value of the vehicle connecting pipe connection; the vehicle sensor is also connected to the control device to transmit the pressure value of the vehicle connecting pipe connection to the control device.

9. The testing equipment for vehicle brakes according to claim 4, characterized in that, The gas supply device also includes a body and an elastic element. The body is provided with the gas supply port. One end of the elastic element is connected to the gas supply valve, and the other end is connected to the body. In the initial state, the elastic element is in the normal state. The push rod pushes the air supply valve to move in the first direction. When the air supply valve is opened, the elastic element is in a stretched state. When the push rod moves in the second direction, the elastic element drives the air supply valve back to its initial state.

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