Power control valve, variable displacement piston pump control system, control method and swash plate type variable displacement piston pump

Abstract

The invention discloses a power control valve, a variable displacement piston pump control system, a variable displacement piston pump control method and a swash plate type variable displacement piston pump in the technical field of hydraulic control. The power control valve comprises a push rod, a valve body, a valve element assembly and a spring assembly and further comprises a pump variable transmission device, an armature and an electromagnetic coil; a valve cavity is formed in the valve body, a push rod, a valve element assembly, a spring assembly and an armature are sequentially arranged in the valve cavity, and the outer side of the push rod extends out of the valve cavity to make contact with a pump variable transmission device. The electromagnetic coil surrounds the armature and is arranged on the outer side of the valve body; the pump variable transmission device is connected with a swash plate of the swash plate type variable plunger pump and used for pushing the push rod, oil liquid of the oil inlet X acts on the end face of the valve element to push the valve element assembly to jointly overcome the spring force of the spring assembly, and when the pressure of the oil liquid input by the oil inlet X continues to be increased to reach a set value, the oil drainage port T and the oil inlet X are communicated. The power limiting point of the electric control variable pump can be changed, and the limiting power of the hydraulic pump can be changed according to the environment and working conditions.

Description

Technical Field

[0001] The present invention relates to a power control valve, a variable plunger pump control system, a control method and a swash plate type variable plunger pump, belonging to the technical field of hydraulic control. Background Art

[0002] Variable displacement piston pumps, with their variable displacement mechanism, can adjust their output characteristics within a certain range based on operational needs. This feature has led to their widespread use in numerous hydraulic systems. Variable displacement mechanisms come in a variety of forms, including manual, motorized, electric, hydraulic, and electro-hydraulic proportional control. Their control functions are categorized into four main types: displacement regulation, flow regulation, pressure regulation, and power regulation.

[0003] Swash plate variable displacement piston pumps with electro-hydraulic proportional control are widely used in wheeled crane pump control systems due to their high precision, fast response, and flexible flow control. By adjusting the current in the solenoid valve, precise control of the pump's output flow rate can be achieved, achieving high control accuracy. Electrical control responds faster than hydraulic control, allowing cranes using electro-hydraulic proportional control piston pumps to quickly adapt to load changes and improve the overall dynamic performance of the crane.

[0004] When using electro-hydraulic proportional variable pumps on construction machinery, there's a need for power limitation. This means the pump output power cannot continue to rise after reaching a certain level, otherwise it would exceed engine power and cause the engine to stall. Currently, electro-hydraulic proportional variable pumps on construction machinery achieve this power limitation by limiting the pump's input current. However, if the pump's control characteristics shift due to environmental factors or if a control system malfunction causes pump current deviation, the pump power can exceed the engine power, leading to a stall. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a power control valve, a variable piston pump control system, a control method and a swash plate type variable piston pump.

[0006] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0007] In the first aspect, the present invention discloses a power control valve, comprising: a push rod, a valve body, a valve core assembly, a spring assembly, and also comprising: a pump variable transmission device, an armature and an electromagnetic coil. The valve body is provided with a valve cavity, in which a push rod, a valve core assembly, a spring assembly and an armature are sequentially provided, wherein the outer side of the push rod extends out of the valve cavity and contacts the pump variable transmission device; The electromagnetic coil is arranged on the outside of the valve body around the armature; The valve body is provided with an oil inlet X and an oil drain port T, and is connected to the valve cavity, with the oil inlet X being on the outside and the oil drain port T being on the inside; The pump variable transmission device is connected to the swash plate of the swash plate type variable piston pump, and is used to push the oil in the push rod oil inlet X to act on the valve core end surface to push the valve core assembly to overcome the spring force of the spring assembly. When the oil pressure input at the oil inlet X continues to increase and reaches the set value, the oil drain port T is connected to the oil inlet X.

[0008] Furthermore, the pump variable transmission device includes: a fixed plate, a connecting rod and a rocker arm; One end of the fixed plate is connected to one end of the connecting rod, the other end of the fixed plate is connected to the swash plate, the other end of the connecting rod is connected to one end of the rocker arm, and the other end of the rocker arm contacts the push rod.

[0009] Furthermore, the other end of the rocker arm is provided with a hemispherical protrusion for contacting the push rod.

[0010] Furthermore, the valve core assembly includes a valve sleeve and a valve core arranged in the valve sleeve.

[0011] Furthermore, the spring assembly includes a spring seat and a spring arranged therewith, and one end of the spring assembly close to the valve core assembly is a movable end, and the other end is a fixed end.

[0012] In a second aspect, the present invention further discloses a variable piston pump control system, comprising: an electric proportional displacement valve, a pressure cut-off valve, a load-sensing valve, a variable cylinder, and the power control valve as described in the first aspect; Among them, the P port of the electric proportional displacement valve is connected to the outlet of the variable piston pump, the A port of the electric proportional displacement valve is connected to the oil port of the variable cylinder, and the T port of the electric proportional displacement valve is connected to the A port of the pressure cut-off valve; The P port of the pressure cut-off valve is connected to the variable plunger pump outlet, and the T port of the pressure cut-off valve is connected to the A port of the load-sensing valve. The left and right ends of the valve core of the pressure cut-off valve are connected to the variable plunger pump outlet and the variable plunger pump oil drain channel respectively; the P port of the load-sensing valve is connected to the variable plunger pump outlet, and the two ends of the valve core of the load-sensing valve are connected to the pump outlet oil channel and the load feedback LS oil channel respectively. The power control valve is connected to the swash plate of the variable piston pump through a transmission mechanism. The A port of the power control valve is connected to the load feedback LS oil channel, and the B port of the power control valve is connected to the oil drain line of the variable piston pump. The variable cylinder has two oil ports, one of which is connected to the A port of the electric proportional displacement valve, and the other is connected to the T port of the electric proportional displacement valve through a one-way valve; Port A and port B represent the working oil port, port P represents the oil inlet port, port T represents the oil return port, and port LS represents the load feedback port.

[0013] In a third aspect, the present invention further discloses a control method for a variable displacement piston pump control system, comprising: Obtain the variable control current of the variable piston pump; controlling the current to control the tilt angle of the swash plate according to the variable; Get the maximum allowable output power of the variable piston pump; When the swash plate is working, the rotation of the swash plate is converted into the axial displacement of the push rod of the power control valve through the variable transmission device, and the variable plunger pump is controlled to work within the maximum allowable output power in conjunction with the oil pressure of the X port.

[0014] Furthermore, it also includes: When the pressure of the variable piston pump is high and the displacement continues to increase, the power control valve overcomes the spring force under the combined action of the push rod thrust and the pressure of the X port, connecting the X port and the T port; The pressure at port X decreases, and the oil at the outlet of the variable piston pump passes through the left position of the load-sensing valve and enters the variable cylinder, pushing the swash plate to move in the direction of reducing displacement until the maximum allowable output power of the variable piston pump is reached.

[0015] Furthermore, the maximum allowable output power of the variable displacement piston pump is adjusted by the magnitude of the current of the electromagnetic coil of the input power control valve.

[0016] In a fourth aspect, the present invention further discloses a swash plate variable displacement piston pump, comprising the variable displacement piston pump control system described in the second aspect.

[0017] The beneficial effects achieved by the present invention are: The present invention is different from the existing power limitation method of the electronically controlled variable pump. The plunger pump can realize its own power control without the need to use a program to control the variable control current of the pump under different load pressures. The present invention has the function of changing the power limit point of the electronically controlled variable pump. The variable pump can change the hydraulic pump limit power according to the environment and working conditions to ensure that the hydraulic pump operates within the engine output power range, avoiding the hydraulic system power exceeding the engine power and causing the engine to stall. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the power control valve structure; Figure 2 It is a schematic diagram of the structure of the variable transmission device of the pump; Figure 3 This is a schematic diagram of the variable piston pump control system principle; Figure 4 It is a structural diagram of a swash plate variable displacement piston pump.

[0019] In the figure: 01, electric proportional displacement valve; 02, pressure cut-off valve; 03, load-sensing valve; 04, variable cylinder; 05, power control valve; 1, pump variable transmission device; 2, push rod; 3, valve body; 4, valve sleeve; 5, valve core; 6, spring seat; 7, spring; 8, armature; 9, solenoid coil; 11, fixing plate; 12, connecting rod; 13, nut; 14, gasket; 15, rocker arm; 21, main shaft; 22, swash plate; 23, slipper; 24, plunger; 25, cylinder body. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0023] Example 1, as Figure 1 As shown, this embodiment introduces a power control valve, including: a push rod 2, a valve body 3, a valve core assembly, a spring assembly, and also includes: a pump variable transmission device 1, an armature 8 and an electromagnetic coil 9; The valve body 3 is provided with a valve cavity, in which a push rod 2, a valve core assembly, a spring assembly and an armature 8 are sequentially provided, wherein the outer side of the push rod 2 extends out of the valve cavity and contacts the pump variable transmission device 1; The electromagnetic coil 9 is arranged on the outside of the valve body 3 around the armature 8; The valve body 3 is provided with an oil inlet X and an oil drain port T, and is connected to the valve cavity, with the oil inlet X being on the outside and the oil drain port T being on the inside; The pump variable transmission device 1 is connected to the swash plate of the swash plate variable piston pump and is used to push the oil at the oil inlet X of the push rod 2 to act on the end surface of the valve core to push the valve core assembly to overcome the spring force of the spring assembly. When the oil pressure input at the oil inlet X continues to increase and reaches a set value, the oil drain port T is connected to the oil inlet X. The swash plate cooperates with the pump variable transmission device 1 of the power control valve to achieve the function of adding a variable power limit point to the electronically controlled pump.

[0024] In this embodiment, Figure 2 As shown, the pump variable transmission device 1 includes: a fixed plate 11, a connecting rod 12, and a rocker arm 15. One end of the fixed plate 11 is connected to one end of the connecting rod 12, the other end of the fixed plate 11 is connected to the swash plate, the other end of the connecting rod 12 is connected to one end of the rocker arm 15, and the other end of the rocker arm 15 contacts the push rod 2. Specifically, the fixed plate 11 is connected to the end surface of the swash plate via screws, and a square hole is machined into the fixed plate 11. The connecting rod 12 has the appearance features of a cylinder, a quadrangular prism, and a threaded column from the middle to the ends. The lower end of the connecting rod 12 is inserted into the square hole of the fixed plate 11 and connected to the fixed plate 11 via a nut and a washer. The axis of the connecting rod 12 coincides with the rotation axis of the swash plate. The upper end of the connecting rod 12 is connected to the rocker arm 15 via a nut 13 and a washer 14. The other end of the rocker arm 15 is provided with a hemispherical protrusion for contacting the push rod 2. The interaction between the swash plate and the power control valve is achieved through the pump variable transmission device 1, thereby converting the inclination angle of the plunger pump swash plate into the axial displacement of the power limiting valve push rod, controlling the opening and closing of the power control valve, and realizing the power limitation of the electronically controlled variable pump itself.

[0025] The valve core assembly includes a valve sleeve 4 and a valve core 5 arranged in the valve sleeve; the spring assembly includes a spring seat 6 and a spring 7 arranged therewith, and one end of the spring assembly close to the valve core assembly is a movable end, and the other end is a fixed end; thereby realizing the construction of the overall structure of the power control valve.

[0026] Example 2 is based on the same inventive concept as Example 1. This example introduces a variable piston pump control system, including: an electric proportional displacement valve 01, a pressure cut-off valve 02, a load-sensitive valve 03, a variable cylinder 04 and the power control valve 05 described in Example 1.

[0027] The specific connection relationship of this embodiment is: Among them, Figure 3As shown, the electric proportional displacement valve 01 is integrated in the variable piston pump housing, the P port of the electric proportional displacement valve 01 is connected to the variable piston pump outlet, the A port of the electric proportional displacement valve 01 is connected to the oil port of the variable cylinder 04, and the T port of the electric proportional displacement valve 01 is connected to the A port of the pressure cut-off valve 02; the pressure cut-off valve 02 and the load sensing valve 03 are installed on the variable piston pump housing, the P port of the pressure cut-off valve 02 is connected to the variable piston pump outlet, the A port of the pressure cut-off valve 02 is connected to the T port of the electric proportional displacement valve 01 through the oil channel inside the housing, the T port of the electric proportional displacement valve 01 is connected to the A port of the load sensing valve 03, and the left and right ends of the valve core of the pressure cut-off valve 02 are connected to the variable piston pump outlet and the variable piston pump oil drain channel respectively; the P port of the load sensing valve 03 is connected to the variable piston pump outlet, and the A port of the load sensing valve 03 is connected to the pressure cut-off valve 02 The T port of load-sensing valve 03 is connected to the variable piston pump drain channel. The two ends of the valve core of load-sensing valve 03 are connected to the variable piston pump outlet oil channel and the load feedback LS oil channel, respectively. Power control valve 05 is mounted on the variable piston pump housing and connected to the variable piston pump's swash plate through a transmission mechanism. Port A of power control valve 05 is connected to the load feedback LS oil channel, and the outlet of power control valve 05 is connected to the variable piston pump drain channel. Variable cylinder 04 has two oil ports: one is connected to port A of electric proportional displacement valve 01, and the other is connected to port T of electric proportional displacement valve 01 through a one-way valve.

[0028] Port A and port B represent the working oil ports, port P represents the oil inlet port, port T represents the oil return port, port LS represents the load feedback port, port S represents the variable piston pump oil suction port, port B1 represents the variable piston pump oil outlet port, and port L represents the oil drain port.

[0029] Example 3, based on the same inventive concept as the other examples, introduces a control method for a variable piston pump control system, including: When an electrically controlled variable displacement piston pump is operating, the pump's swashplate rotates a certain angle based on the input variable control current. The variable transmission device converts this rotation into axial displacement of the power control valve's push rod. If the swashplate's rotation angle is small (i.e., the variable displacement pump is at a low displacement), the corresponding push rod thrust is small, and the X-port pressure required to open the power valve is high. If the swashplate's rotation angle is large (i.e., the variable displacement pump is at a high displacement), the corresponding push rod thrust is high, and the X-port pressure required to open the power valve is low.

[0030] Therefore, when the pressure of the electronically controlled variable pump is high and the displacement continues to increase, the power control valve overcomes the spring force under the combined action of the push rod thrust and the X-port pressure, connects the X-port and T-port of the power control valve, and the X-port pressure decreases. The pump outlet oil passes through the left position of the load-sensing valve and enters the variable cylinder, pushing the swash plate to move in the direction of reducing displacement until the pump limit power is reached.

[0031] The maximum allowable power of the electric variable pump can be adjusted by the input current of the power control valve solenoid coil. When the input current is large, the spring force is large and the maximum allowable power is large.

[0032] Example 4 is based on the same inventive concept as the other examples. Figure 4 As shown, this embodiment introduces a swash plate type variable piston pump, including the variable piston pump control system described in Example 2.

[0033] In this embodiment, the structure of the swash plate variable piston pump includes a main shaft 21, a swash plate 22, a slipper 23, a plunger 24 and a cylinder body 25 arranged in sequence; the electric proportional displacement valve 01, the pressure cut-off valve 02, the load sensing valve 03 and the power control valve 05 are installed on the pump housing.

[0034] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0035] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0036] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0037] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A power control valve, comprising: A push rod (2), a valve body (3), a valve core assembly, and a spring assembly, characterized in that it also includes: a pump variable transmission device (1), an armature (8), and an electromagnetic coil (9); The valve body (3) is provided with a valve cavity, and a push rod (2), a valve core assembly, a spring assembly and an armature (8) are sequentially provided in the valve cavity, wherein the outer side of the push rod (2) extends out of the valve cavity and contacts the pump variable transmission device (1); The electromagnetic coil (9) is arranged around the armature (8) on the outside of the valve body (3); The valve body (3) is provided with an oil inlet X and an oil drain port T, and is connected to the valve cavity, with the oil inlet X being located outside and the oil drain port T being located inside; The pump variable transmission device (1) is connected to the swash plate of the swash plate type variable piston pump, and is used to push the oil in the oil inlet X of the push rod (2) to act on the end face of the valve core to push the valve core assembly to overcome the spring force of the spring assembly. When the oil pressure input into the oil inlet X continues to increase and reaches a set value, the oil drain port T is connected to the oil inlet X.

2. The power control valve according to claim 1, characterized in that: The pump variable transmission device (1) comprises: a fixed plate (11), a connecting rod (12) and a rocker arm (15); One end of the fixed plate (11) is connected to one end of the connecting rod (12), the other end of the fixed plate (11) is connected to the swash plate, the other end of the connecting rod (12) is connected to one end of the rocker arm (15), and the other end of the rocker arm (15) is in contact with the push rod (2).

3. The power control valve according to claim 2, characterized in that: The other end of the rocker arm (15) is provided with a hemispherical protrusion for contacting the push rod (2).

4. The power control valve according to claim 1, characterized in that: The valve core assembly comprises a valve sleeve (4) and a valve core (5) arranged in the valve sleeve.

5. The power control valve according to claim 1, characterized in that: The spring assembly comprises a spring seat (6) and a spring (7) arranged in combination therewith; one end of the spring assembly close to the valve core assembly is a movable end, and the other end is a fixed end.

6. A variable piston pump control system, characterized in that: include: An electric proportional displacement valve (01), a pressure cut-off valve (02), a load-sensing valve (03), a variable cylinder (04), and a power control valve (05) as claimed in any one of claims 1 to 5; Among them, the P port of the electric proportional displacement valve (01) is connected to the outlet of the variable piston pump, the A port of the electric proportional displacement valve (01) is connected to the oil port of the variable cylinder (04), and the T port of the electric proportional displacement valve (01) is connected to the A port of the pressure cut-off valve (02); The P port of the pressure cut-off valve (02) is connected to the outlet of the variable plunger pump, the T port of the pressure cut-off valve (02) is connected to the A port of the load sensing valve (03), and the left and right ends of the valve core of the pressure cut-off valve (02) are respectively connected to the outlet of the variable plunger pump and the oil drain channel of the variable plunger pump; the P port of the load sensing valve (03) is connected to the outlet of the variable plunger pump, and the two end surfaces of the valve core of the load sensing valve (03) are respectively connected to the pump outlet oil channel and the load feedback LS oil channel; The power control valve (05) is connected to the swash plate of the variable piston pump through a transmission mechanism, the A port of the power control valve (05) is connected to the load feedback LS oil passage, and the B port of the power control valve (05) is connected to the oil drain passage of the variable piston pump; The variable cylinder has two oil ports, one of which is connected to the A port of the electric proportional displacement valve (01), and the other is connected to the T port of the electric proportional displacement valve (01) through a one-way valve; Port A and port B represent the working oil port, port P represents the oil inlet port, port T represents the oil return port, and port LS represents the load feedback port.

7. A control method based on the variable piston pump control system according to claim 6, characterized in that: include: Obtain the variable control current of the variable piston pump; controlling the current to control the tilt angle of the swash plate according to the variable; Get the maximum allowable output power of the variable piston pump; When the swash plate is working, the rotation of the swash plate is converted into the axial displacement of the push rod of the power control valve (05) through the variable transmission device, and the variable piston pump is controlled to work within the maximum allowable output power in conjunction with the oil pressure of the X port.

8. The control method according to claim 7, characterized in that: Also includes: When the pressure of the variable piston pump is high and the displacement continues to increase, the power control valve (05) overcomes the spring force under the combined action of the push rod thrust and the pressure at port X, connecting port X and port T; The pressure at port X decreases, and the oil at the outlet of the variable piston pump passes through the left position of the load sensing valve (03) and enters the variable cylinder (04), pushing the swash plate to move in the direction of reducing displacement until the maximum allowable output power of the variable piston pump is reached.

9. The control method according to claim 7, characterized in that: The maximum permissible output power of the variable displacement plunger pump is adjusted by the magnitude of the electromagnetic coil current of the input power control valve (05).

10. A swash plate type variable displacement piston pump, comprising the variable displacement piston pump control system according to claim 6.

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