System for controlling retarder torque through electric pump and solenoid valve

Abstract

The present invention provides a system for controlling the torque of a retarder through an electric pump and a solenoid valve, and relates to the technical field of vehicle retarding mechanical devices. The system for controlling the torque of a retarder through an electric pump and a solenoid valve comprises a retarding mechanical device, a discharge valve, an electric oil pump and a current limiting device; the retarding mechanical device has a high-pressure chamber and a low-pressure chamber; the discharge valve is connected to the retarding mechanical device; the electric oil pump is connected to the discharge valve; the electric oil pump is connected to the retarding mechanical device; the current limiting device is arranged at the output port of the low-pressure chamber, and the opening of the current limiting device is adjustable, and the opening size of the current limiting device controls the torque size of the retarding mechanical device. The system for controlling the torque of a retarder through an electric pump and a solenoid valve not only alleviates the technical problem of the relatively slow torque regulation reaction speed of the retarding mechanical device existing in the prior art, but also achieves the technical effect of rapid torque regulation reaction and precise control, and enables the positive displacement pump principle to be applied to the retarding mechanical device.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle retarding mechanical devices, and in particular to a system for controlling the torque of a retarder through an electric pump and a solenoid valve. Background Art

[0002] Due to the large number of intersections, dense bus stops and large passenger flow on urban roads, buses often need to brake frequently; mountain roads are steep and have many sharp turns, and medium and large trucks and buses that travel on mountain roads for a long time also need to brake frequently. When the brakes work frequently for a long time, the brake shoes will wear quickly, the service life of the brake friction pads will be shortened, and the braking force will be lost or the braking performance will be greatly reduced due to the thermal decay of the brakes. Therefore, it is very necessary to equip the auxiliary braking system.

[0003] As an auxiliary braking component of the vehicle, the retarding mechanical device reduces the load of the original vehicle's braking system by acting on the original vehicle's transmission system, so that the vehicle can be decelerated evenly, thereby improving the reliability of the vehicle's braking system, extending the service life of the braking system, and significantly reducing the vehicle's operating costs.

[0004] At present, the retarding mechanical device includes a hydraulic retarding mechanical device. The hydraulic retarding mechanical device has at least the disadvantages of relatively slow reaction speed and insufficient low-speed braking force. Moreover, the current hydraulic retarding mechanical devices all adopt the principle of a stator-rotor mixed flow pump, which can enable the positive displacement pump to unload when it is no-load, resulting in very small no-load resistance. Therefore, the positive displacement pump principle can be applied to the retarding mechanical device. Summary of the invention

[0005] The object of the present invention is to provide a system for controlling the torque of a retarder through an electric pump and a solenoid valve, so as to alleviate the technical problem of relatively slow torque regulation reaction speed of the retarder mechanical device existing in the prior art.

[0006] The present invention provides a system for controlling the torque of a retarder through an electric pump and a solenoid valve, comprising: a retarder mechanical device, an unloading valve, an electric oil pump and a current limiting device;

[0007] The deceleration mechanical device has a high-pressure chamber and a low-pressure chamber; the unloading valve is connected to the high-pressure chamber and the low-pressure chamber respectively through two oil passages, and when unloaded, the unloading valve opens to connect the high-pressure chamber with the low-pressure chamber;

[0008] The electric oil pump is connected to the unloading valve, and the electric oil pump sucks medium oil from the oil storage chamber to increase the pressure of the unloading valve, so that the unloading valve is closed;

[0009] The electric oil pump is connected to the deceleration mechanical device, and the electric oil pump sucks medium oil from the oil storage chamber to increase the pressure of the high-pressure chamber;

[0010] The current limiting device is arranged at the output port of the low-pressure chamber, and the opening of the current limiting device is adjustable. The opening size of the current limiting device controls the torque size of the deceleration mechanical device.

[0011] Further, the unloading valve has a first working chamber and a second working chamber, the first working chamber has a high-pressure connection port, a low-pressure connection port and a control connection port, and the second working chamber has an oil storage chamber connection port;

[0012] The high-pressure connection port is connected to the high-pressure chamber, and the low-pressure connection port is connected to the low-pressure chamber;

[0013] The electric oil pump is connected to a first oil circuit, a second oil circuit and a third oil circuit. The first oil circuit is used to connect to the oil storage chamber. The second oil circuit is arranged in parallel with the third oil circuit. The second oil circuit is connected to the control connection port. The third oil circuit is connected to the high-pressure chamber.

[0014] Furthermore, a first solenoid valve is provided on the first oil circuit, and when the first solenoid valve is powered off, the electric oil pump is connected to the oil storage chamber.

[0015] Furthermore, the third oil circuit is provided with a second solenoid valve and a third solenoid valve which are arranged in series, and when both are powered on, the electric oil pump is connected to the high-pressure chamber through the third oil circuit.

[0016] Furthermore, the first solenoid valve is a reversing valve;

[0017] The second solenoid valve and the third solenoid valve are both two-position three-way valves.

[0018] Furthermore, an oil inlet one-way valve is also provided on the third oil circuit, and the oil inlet one-way valve is located between the third solenoid valve and the high-pressure chamber.

[0019] Furthermore, a fourth oil circuit is connected between the third solenoid valve and the high-pressure chamber, and the fourth oil circuit is arranged in parallel with the third oil circuit section between the third solenoid valve and the high-pressure chamber;

[0020] The third solenoid valve is in a power-off state and is connected to the high-pressure chamber through the fourth oil path;

[0021] Wherein, the unloading valve is in an open state, and the electric oil pump sucks medium oil from the oil storage chamber to replenish oil for the high-pressure chamber and the low-pressure chamber.

[0022] Furthermore, the output port of the low-pressure chamber and the connecting port of the oil storage chamber are connected to the oil storage chamber via a fifth oil circuit;

[0023] The flow limiting device comprises a flow limiting opening regulating valve, and the flow limiting opening regulating valve is arranged in the fifth oil circuit.

[0024] Furthermore, the unloading valve is provided in plurality, and the plurality of unloading valves are provided in parallel.

[0025] Furthermore, the electric oil pump is installed on the housing of the retarder mechanical device.

[0026] Beneficial effects:

[0027] The present invention provides a system for controlling the torque of a retarder through an electric pump and a solenoid valve, wherein the electric oil pump is connected to the unloading valve, and the electric oil pump can suck medium oil from the oil storage chamber to increase the pressure of the unloading valve, so that the unloading valve is in a closed state. At this time, the direct interconnection between the high-pressure chamber and the low-pressure chamber is disconnected; furthermore, through the control of the electric oil pump (rotation speed), increasing the rotation speed can make the electric oil pump suck medium oil from the oil storage chamber to increase the pressure of the high-pressure chamber, and conversely, reducing the rotation speed can reduce the pressure. Since a current limiting device is provided at the output port of the low-pressure chamber, and the opening of the current limiting device is adjustable, during this process, when the opening of the current limiting device is small, the torque of the retarder mechanical device can be increased, thereby achieving torque increase; conversely, when the opening of the current limiting device is large, the torque of the retarder mechanical device can be reduced, thereby achieving torque reduction.

[0028] In addition, the system of the present invention controls the torque of the retarder through an electric pump and a solenoid valve, generates control pressure for controlling the unloading valve through the electric oil pump and inhales medium oil from the oil storage chamber to increase the pressure of the high-pressure chamber. Since the electric oil pump responds quickly and has precise control, the response speed of increasing and reducing torque can be relatively fast and relatively precise. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of a system for controlling the torque of a retarder through an electric pump and a solenoid valve provided in an embodiment of the present invention;

[0031] Figure 2 A torque increase and decrease principle diagram of a system for controlling the torque of a retarder through an electric pump and a solenoid valve provided in an embodiment of the present invention, wherein the solid line is a passage, the dotted line is an open circuit, and the arrow indicates the flow path of the high-viscosity oil medium;

[0032] Figure 3 The oil replenishment principle diagram of the system for controlling the torque of the retarder through the electric pump and the solenoid valve provided by the embodiment of the present invention, wherein the solid line is the passage, the dotted line is the open circuit, and the arrow indicates the flow path of the high-viscosity oil medium;

[0033] Figure 4 A schematic structural diagram of a high-viscosity oil medium retarding mechanical device provided in an embodiment of the present invention.

[0034] icon:

[0035] 10-first oil circuit; 20-second oil circuit; 30-third oil circuit; 40-fourth oil circuit; 50-fifth oil circuit; 60-oil storage chamber;

[0036] 100-speed retarding mechanism; 110-high pressure chamber; 120-low pressure chamber;

[0037] 200-unloading valve; 210-high pressure connection port; 220-low pressure connection port; 230-control connection port; 240-oil storage chamber connection port;

[0038] 300-Electric oil pump;

[0039] 400-current limiting device;

[0040] 500-first solenoid valve;

[0041] 600-second solenoid valve;

[0042] 700-the third solenoid valve;

[0043] 800-Oil inlet check valve. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0047] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0048] In addition, the terms "horizontal" and "vertical" do not mean that the components must be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0049] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0051] Reference Figure 1 and Figure 2 The present embodiment provides a system for controlling the torque of a retarder through an electric pump and a solenoid valve, comprising a retarder mechanism 100, a relief valve 200, an electric oil pump 300 and a current limiting device 400; the retarder mechanism 100 has a high-pressure chamber 110 and a low-pressure chamber 120; the relief valve 200 is connected to the retarder mechanism 100; the electric oil pump 300 is connected to the relief valve 200, and the electric oil pump 300 sucks medium oil from the oil storage chamber 60 to increase the pressure of the relief valve 200, so that the relief valve is closed; the electric oil pump 300 is connected to the retarder mechanism 100, and the electric oil pump 300 sucks medium oil from the oil storage chamber 60 to increase the pressure of the high-pressure chamber 110; the current limiting device 400 is arranged at the output port of the low-pressure chamber 120, and the opening of the current limiting device 400 is adjustable, and the opening size of the current limiting device 400 controls the torque size of the retarder mechanism 100.

[0052] The present embodiment provides a system for controlling the torque of the retarder through an electric pump and a solenoid valve. The electric oil pump 300 sucks medium oil from the oil storage chamber 60 to increase the pressure of the unloading valve 200, so that the unloading valve 200 is in a closed state. At this time, the direct interconnection between the high-pressure chamber 110 and the low-pressure chamber 120 is disconnected; furthermore, by controlling the electric oil pump 300 (rotation speed), the electric oil pump 300 can suck medium oil from the oil storage chamber 60 to increase the pressure of the high-pressure chamber 110, and conversely, reducing the rotation speed can reduce the pressure. Since the output port of the low-pressure chamber 120 is provided with a flow limiting device 400, and the opening of the flow limiting device 400 is adjustable, in this process, when the opening of the flow limiting device 400 is small, the torque of the retarder mechanical device 100 can be increased, thereby achieving torque increase; conversely, when the opening of the flow limiting device 400 is large, the torque of the retarder mechanical device 100 can be reduced, thereby achieving torque reduction.

[0053] In addition, the control pressure of the unloading valve 200 is generated by the electric oil pump 300, and the medium oil is sucked from the oil storage chamber 60 to build up pressure in the high-pressure chamber 110. Since the electric oil pump 300 responds quickly and controls accurately, the torque increase and torque reduction response speed can be relatively fast and relatively accurate.

[0054] It should be noted that the deceleration mechanism 100 mainly adopts a cycloidal rotor type, blade type, planetary gear type and other mechanical structures arranged in the main cavity. The input shaft and the transmission shaft of the gearbox are connected by a speed-increasing and torque-reducing gear. Driven by the torque of the transmission shaft, a rotational motion is generated. The pressure change in the cavity drives the liquid (medium oil) in the cavity to circulate. Under the action of flow damping, mechanical energy is converted into heat energy, and finally a vehicle braking force is generated to realize the vehicle deceleration function.

[0055] Among them, the high-pressure chamber 110 and the low-pressure chamber 120 of the deceleration mechanism 100 are collectively referred to as working chambers, and high pressure and low pressure are relative. The high-pressure chamber 110 and the low-pressure chamber 120 are generated by the operation of the deceleration mechanism 100. As the pressure of the high-pressure chamber 110 gradually increases, the high- and low-pressure chamber channel opening pistons can be controlled to make the high- and low-pressure chamber channel openings gradually smaller, and vice versa. The high-pressure chamber 110 and the low-pressure chamber 120 are conventional names in the art, which are clear to those skilled in the art, and the specific structure of the deceleration mechanism 100 and the specific formation methods of the high-pressure chamber 110 and the low-pressure chamber 120 will not be described in detail here.

[0056] In a specific embodiment of the present application, the unloading valve 200 has a first working chamber and a second working chamber, the first working chamber has a high-pressure connecting port 210, a low-pressure connecting port 220 and a control connecting port 230, and the second working chamber has an oil storage chamber connecting port 240; the high-pressure connecting port 210 is connected to the high-pressure chamber 110, and the low-pressure connecting port 220 is connected to the low-pressure chamber 120; the electric oil pump 300 is connected to the first oil circuit 10, the second oil circuit 20 and the third oil circuit 30, the first oil circuit 10 is used to connect to the oil storage chamber 60, the second oil circuit 20 and the third oil circuit 30 are arranged in parallel, and the second oil circuit 20 is connected to the control connecting port 230; the third oil circuit 30 is connected to the high-pressure chamber 110.

[0057] It should be noted that the unloading valve 200 includes a valve body, in which a piston is provided. The piston divides the cavity in the valve body into a first working chamber and a second working chamber, and the volume of the first working chamber and the second working chamber increases or decreases with the movement of the piston. Furthermore, a return spring is provided between the piston and the second working chamber for returning the piston.

[0058] During specific operation, the electric oil pump 300 can build up pressure for the unloading valve 200. Specifically, under the pressurized state, the piston can move to the right, compressing the return spring, and the unloading valve 200 is closed, that is, the high-pressure connecting port 210 is disconnected from the low-pressure connecting port 220; under the decompressed state, the return spring returns to cause the piston to move to the left, and the unloading valve 200 is opened, that is, the high-pressure connecting port 210 is connected to the low-pressure connecting port 220.

[0059] Simply put, the electric oil pump 300 can generate a control pressure to control the unloading valve 200. When the pressure acts on the left side of the piston, that is, when pressurized, the unloading valve 200 is closed; when there is no pressure on the left side of the piston, the piston overcomes the return spring force, that is, when decompressed, the unloading valve 200 opens.

[0060] Reference Figure 2 A first solenoid valve 500 is provided on the first oil circuit 10 . When the first solenoid valve 500 is powered off, the electric oil pump 300 is connected to the oil storage chamber 60 .

[0061] Under the control of the first solenoid valve 500 , the electric oil pump 300 can suck medium oil from the oil storage chamber 60 to increase the pressure of the unloading valve 200 , so that the unloading valve is closed.

[0062] Please continue to refer to Figure 2 The third oil circuit 30 is provided with a second solenoid valve 600 and a third solenoid valve 700 which are arranged in series. When both are powered on, the electric oil pump 300 is connected to the high-pressure chamber 110 through the third oil circuit 30. With this arrangement, under the control of the first solenoid valve 500, the second solenoid valve 600 and the third solenoid valve 700, the electric oil pump 300 can suck medium oil from the oil storage chamber 60 and pressurize the high-pressure chamber 110 through the third oil circuit 30.

[0063] The first solenoid valve 500 is a reversing valve; the second solenoid valve 600 and the third solenoid valve 700 are both two-position three-way valves.

[0064] Specifically, by directly controlling the electric oil pump 300, different output control hydraulics are generated. The first solenoid valve 500 is a reversing valve for the electric oil pump 300 to suck in medium oil, and sucks in medium oil from the oil storage chamber 60 when the power is off; the second solenoid valve 600 and the third solenoid valve 700 are two-position three-way valves, which together close the atmospheric passage of the working chamber (the high-pressure chamber 110 and the low-pressure chamber 120), and at the same time open the output hydraulic passage of the electric oil pump 300, so that the electric oil pump 300 can suck in medium oil from the oil storage chamber 60; the output hydraulic pressure of the electric oil pump 300 is increased, the opening of the high and low pressure chamber passages in the working chamber is reduced, the working chamber rotor starts to work, and the torque is increased.

[0065] Please continue to refer to Figure 2 The third oil circuit 30 is also provided with an oil inlet check valve 800 , which is located between the third solenoid valve 700 and the high-pressure chamber 110 to allow the medium oil to flow in one direction, that is, to flow into the high-pressure chamber 110 .

[0066] Specifically, the flow path for increasing and decreasing torque is:

[0067] The first solenoid valve 500 is powered off, the second solenoid valve 600 and the third solenoid valve 700 are powered on, the electric oil pump 300 sucks medium oil from the oil storage chamber 60, and part of the medium oil enters the first working chamber of the unloading valve 200 through the second oil circuit 20 and the control connection port 230. According to the different output control hydraulic pressures generated by the electric oil pump 300, the degree of connectivity between the high-pressure connection port 210 and the low-pressure connection port 220 is adjusted, such as being completely disconnected; another part of the medium oil enters the high-pressure chamber 110 through the third oil circuit 30, squeezes the medium oil in the low-pressure chamber 120, and flows into the oil storage chamber 60 through the fifth oil circuit 50 and the current limiting device 400.

[0068] Reference Figure 3 A fourth oil circuit is also connected between the third solenoid valve 700 and the high-pressure chamber 110, and the fourth oil circuit 40 is arranged in parallel with the third oil circuit section between the third solenoid valve 700 and the high-pressure chamber 110; the third solenoid valve 700 is connected to the high-pressure chamber 110 through the fourth oil circuit 40 when the power is off; wherein the unloading valve 200 is in an open state, and the electric oil pump 300 sucks medium oil from the oil storage chamber 60 to replenish the high-pressure chamber 110 and the low-pressure chamber 120. The electric oil pump 300 works to replenish the working chamber with oil to achieve lubrication or loading.

[0069] It should be noted that the third oil circuit section between the third solenoid valve 700 and the high-pressure chamber 110 , and the fourth oil circuit 40 are arranged in parallel and are not connected at the same time, and can be specifically controlled by the on-off of the third solenoid valve 700 .

[0070] Specifically, the oil replenishment flow path is:

[0071] The first solenoid valve 500 is powered off, the second solenoid valve 600 is powered on, and the third solenoid valve 700 is disconnected. The electric oil pump 300 sucks in the medium oil from the oil storage chamber 60. Under the control of the second solenoid valve 600 and the third solenoid valve 700, the medium oil passes through the third oil circuit 30 between the electric oil pump 300 and the second solenoid valve 600 and enters the high-pressure chamber 110 through the fourth oil circuit 40, squeezes the medium oil in the low-pressure chamber 120, and flows into the oil storage chamber 60 through the fifth oil circuit 50 and the current limiting device 400.

[0072] Reference Figure 1 or Figure 2 In this embodiment, the output port of the low-pressure chamber 120 and the oil storage chamber connecting port 240 are connected to the oil storage chamber 60 through the fifth oil circuit 50; the flow limiting device 400 includes a flow limiting opening regulating valve, and the flow limiting opening regulating valve is arranged in the fifth oil circuit 50.

[0073] Specifically, increasing the opening of the flow-limiting opening regulating valve can reduce the torque, and decreasing the opening of the flow-limiting opening regulating valve can increase the torque.

[0074] On the basis of the above embodiment, the unloading valve 200 may be provided as one or more. Specifically, when the unloading valve 200 is provided as multiple, the multiple unloading valves 200 are provided in parallel.

[0075] In this embodiment, two unloading valves 200 are provided, and the two unloading valves 200 are arranged in parallel, and the first working chambers of the unloading valves 200 are connected to the high-pressure connecting port 210 , and the low-pressure connecting ports 220 are connected to the low-pressure chamber 120 .

[0076] Reference Figure 4 The present embodiment also provides a high-viscosity oil medium retarding mechanical device, which includes the system of controlling the retarder torque through an electric pump and an electromagnetic valve in the aforementioned embodiment. The high-viscosity oil medium retarding mechanical device also provided in the present embodiment includes a system of controlling the retarder torque through an electric pump and an electromagnetic valve, and thus, the technical advantages and effects that can be achieved by the high-viscosity oil medium retarding mechanical device also include the technical advantages and effects that can be achieved by the system of controlling the retarder torque through an electric pump and an electromagnetic valve, which will not be repeated here.

[0077] It should be noted that the medium oil is a high-viscosity oil medium with sufficient fluidity at low temperatures, high-temperature viscosity that can seal end gaps and meshing gaps above 0.08mm, high-temperature resistance, and appropriate flow resistance for easy heat dissipation. Its operating temperature range is -40 to 160 degrees Celsius.

[0078] Specifically, the electric oil pump 300 is installed on the housing of the retarding mechanism 100, and can also be modified according to the layout requirements of the vehicle and arranged at other positions of the housing of the retarding mechanism 100. For example, the electric oil pump 300 can be fastened to the housing of the retarding mechanism 100 by bolts, screws, etc.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for controlling the torque of a retarder by means of an electric pump and a solenoid valve, characterized in that: include: A retarding mechanical device (100), an unloading valve (200), an electric oil pump (300) and a current limiting device (400); The deceleration mechanical device (100) has a high-pressure chamber (110) and a low-pressure chamber (120); the unloading valve (200) is respectively connected to the high-pressure chamber (110) and the low-pressure chamber (120) through two oil passages; when the unloading valve (200) is unloaded, the high-pressure chamber (110) is connected to the low-pressure chamber (120); The electric oil pump (300) is connected to the unloading valve (200), and the electric oil pump (300) sucks medium oil from the oil storage chamber (60) to increase the pressure of the unloading valve (200), so that the unloading valve is closed; The electric oil pump (300) is connected to the deceleration mechanical device (100), and the electric oil pump (300) sucks medium oil from the oil storage chamber (60) to increase the pressure of the high-pressure chamber (110); The flow limiting device (400) is arranged at the output port of the low-pressure chamber (120), and the opening of the flow limiting device (400) is adjustable. The opening size of the flow limiting device (400) controls the torque size of the retarding mechanical device (100).

2. The system for controlling the retarder torque by an electric pump and a solenoid valve according to claim 1, characterized in that: The unloading valve (200) comprises a first working chamber and a second working chamber, the first working chamber comprises a high-pressure connecting port (210), a low-pressure connecting port (220) and a control connecting port (230), and the second working chamber comprises an oil storage chamber connecting port (240); The high-pressure connection port (210) is connected to the high-pressure chamber (110), and the low-pressure connection port (220) is connected to the low-pressure chamber (120); The electric oil pump (300) is connected to a first oil circuit (10), a second oil circuit (20) and a third oil circuit (30); the first oil circuit (10) is used to connect to an oil storage chamber (60); the second oil circuit (20) and the third oil circuit (30) are arranged in parallel; the second oil circuit (20) is connected to the control connection port (230); and the third oil circuit (30) is connected to the high-pressure chamber (110).

3. The system for controlling the torque of a retarder by an electric pump and a solenoid valve according to claim 2, characterized in that: The first oil circuit (10) is provided with a first solenoid valve (500), and when the first solenoid valve (500) is powered off, the electric oil pump (300) is connected to the oil storage chamber (60).

4. The system for controlling the retarder torque by an electric pump and a solenoid valve according to claim 3, characterized in that: The third oil circuit (30) is provided with a second solenoid valve (600) and a third solenoid valve (700) which are arranged in series. When both are powered on, the electric oil pump (300) is connected to the high-pressure chamber (110) through the third oil circuit (30).

5. The system for controlling the retarder torque by an electric pump and a solenoid valve according to claim 4, characterized in that: The first solenoid valve (500) is a reversing valve; The second solenoid valve (600) and the third solenoid valve (700) are both two-position three-way valves.

6. The system for controlling the retarder torque by an electric pump and a solenoid valve according to claim 4, characterized in that: The third oil circuit (30) is also provided with an oil inlet check valve (800), and the oil inlet check valve (800) is located between the third solenoid valve (700) and the high-pressure chamber (110).

7. The system for controlling the retarder torque by an electric pump and a solenoid valve according to claim 4, characterized in that: A fourth oil circuit is also connected between the third solenoid valve (700) and the high-pressure chamber (110), and the fourth oil circuit (40) is arranged in parallel with the third oil circuit section located between the third solenoid valve (700) and the high-pressure chamber (110); When the power is off, the third solenoid valve (700) is in communication with the high-pressure chamber (110) through the fourth oil path (40); The unloading valve (200) is in an open state, and the electric oil pump (300) sucks medium oil from the oil storage chamber (60) to replenish oil for the high-pressure chamber (110) and the low-pressure chamber (120).

8. The system for controlling the torque of a retarder by an electric pump and a solenoid valve according to claim 2, characterized in that: The output port of the low-pressure chamber (120) and the oil storage chamber connecting port (240) are connected to the oil storage chamber (60) via a fifth oil passage (50); The flow limiting device (400) comprises a flow limiting opening regulating valve, and the flow limiting opening regulating valve is arranged in the fifth oil passage (50).

9. The system for controlling the retarder torque by an electric pump and a solenoid valve according to any one of claims 1 to 8, characterized in that: The unloading valve (200) is provided in plurality, and the plurality of unloading valves (200) are arranged in parallel.

10. The system for controlling the torque of a retarder by an electric pump and a solenoid valve according to claim 9, characterized in that: The electric oil pump (300) is mounted on the housing of the retarder mechanical device (100).

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