Proportional flow valve, proportional flow valve control method and hydraulic control system

Abstract

The invention discloses a proportional flow valve, a proportional flow valve control method and a hydraulic control system, and relates to the technical field of hydraulic valves.The proportional flow valve comprises a fluid resistance device, the fluid resistance device is provided with a first oil inlet and a first oil outlet, and the first oil inlet communicates with a main control cavity and a pilot spring cavity; the first oil outlet communicates with the pilot oil inlet and the pilot spring-free cavity, and the pressure of the first oil inlet is larger than that of the first oil outlet. The inlet and outlet pressure of the fluid resistance device is converted into hydraulic pressure acting on the pilot valve element, the output force of the electromagnetic force output device is controlled, the inlet and outlet pressure difference of the fluid resistance device is controlled, pilot valve flow control is achieved, and therefore main valve flow control is achieved. And at least one proportional flow valve is arranged in the hydraulic control system. The output flow of the main valve can be controlled without being influenced by load pressure changes, and the flow control precision is high; the structure of the valve is simplified, the weight is reduced, the pressure loss is reduced, and the system energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic valves, and in particular to a proportional flow valve, a proportional flow valve control method and a hydraulic control system. Background Art

[0002] The proportional flow valve is the core component of the electro-hydraulic control system. It controls the speed of the hydraulic actuator by continuously controlling the flow rate and is widely used in aerospace, mining machinery, marine engineering and other fields.

[0003] There are two types of proportional flow valves: direct-acting and pilot-operated. Large flow valves often use pilot-operated control. Traditional pilot-operated proportional flow valves (such as ordinary Valvistor valves) are Figure 1 As shown, the proportional flow valve consists of a pilot valve and a main cartridge valve. The pilot valve is directly controlled by a proportional solenoid. The main cartridge valve adopts a cone valve cartridge structure with a feedback groove inside, so that the proportional flow valve has a displacement-flow feedback mechanism. The flow of the main cartridge valve is an amplification of the flow of the pilot valve. Therefore, by controlling the pilot valve, continuous proportional control of the flow of the proportional flow valve can be achieved. However, the traditional pilot-operated proportional flow valve will be affected by load changes.

[0004] At present, in order to eliminate the influence of load changes on the proportional flow valve, such as Figure 2 As shown, a pressure compensator 7 is connected in series to the inlet or outlet of the ordinary Valvistor valve to maintain the pressure difference Δp at both ends of the proportional flow valve basically constant to achieve proportional control of the flow. However, the pressure compensator 7 is affected by nonlinear factors such as hydraulic force, which makes the compensation pressure difference fluctuate greatly and the flow deviation is large. In addition, the pressure compensator 7 installed in the oil circuit of the main cartridge valve also reduces the flow capacity of the proportional flow valve, increases the throttling loss, increases the system heat, and the mechanical structure of the proportional flow valve is also relatively complex.

[0005] The Chinese invention patent with the patent number CN102425581A provides a "flow valve and control method for pilot flow closed-loop control". On the basis of the flow amplification proportional cartridge valve, multiple pressure sensors are added to detect the pressure difference at the pilot valve port in real time, and the displacement of the pilot valve core is recalculated and corrected, so as to maintain the pilot valve flow without being affected by the pressure difference change. Then, the mapping relationship between the flow between the pilot valve and the main cartridge valve is used, and according to the flow amplification principle, the flow of the main cartridge valve is basically not affected by the load change. Although this method can overcome the shortcomings of large pressure loss and low precision caused by adding a pressure compensator 7, there are also some problems: 1) The cost of the pressure sensor is high, which is not conducive to the production and sales of proportional flow valve products; 2) As an electronic component, the pressure sensor is prone to failure in harsh working environments. Once the pressure sensor fails, the closed-loop flow control fails completely, which can easily lead to machine out of control and cause safety accidents. Summary of the invention

[0006] The object of the present invention is to provide a proportional flow valve, a proportional flow valve control method and a hydraulic control system to solve the problems existing in the above-mentioned prior art, which can control the output flow of the main valve without being affected by changes in load pressure, and has high flow control accuracy; the valve structure is simplified, the weight is reduced, the pressure loss is reduced, and the system energy consumption is reduced.

[0007] To achieve the above object, the present invention provides the following solutions: The present invention provides a proportional flow valve, comprising a main valve, a pilot valve and a fluid resistance device, wherein: The main valve has a main control chamber; The pilot valve comprises a pilot valve body, a pilot valve core, a pilot spring and an electromagnetic force output device, wherein the pilot valve core is arranged in the pilot valve body and can separate the pilot valve body into a pilot spring chamber and a pilot springless chamber, the pilot spring is arranged in the pilot spring chamber, the pilot spring can abut against the pilot valve core, the electromagnetic force output device is arranged on a side of the pilot valve core away from the pilot spring, and the electromagnetic force output device can drive the pilot valve core to move along the center line of the valve core hole of the pilot valve body by electromagnetic force; the pilot valve body is provided with a pilot oil inlet; The fluid resistance device has a first oil inlet and a first oil outlet, the first oil inlet is connected to both the main control chamber and the pilot spring chamber, the first oil outlet is connected to both the pilot oil inlet and the pilot springless chamber, and the pressure of the first oil inlet is greater than the pressure of the first oil outlet.

[0008] Preferably, it also includes a damping hole, the main valve has a main oil inlet, the main oil inlet is connected to the main control chamber through the damping hole; a flow feedback throttling groove is provided on the main valve, and the pre-opening amount of the flow feedback throttling groove is 0.

[0009] Preferably, it further comprises a displacement detection device, which is arranged on the pilot valve and can detect the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body.

[0010] Preferably, the fluid resistance device is a liquid resistance device or a flow meter.

[0011] Preferably, the liquid resistance device is a single liquid resistance or a liquid resistance network; the liquid resistance network is a series liquid resistance network, a parallel liquid resistance network or a series-parallel liquid resistance network; the series liquid resistance network includes a first series liquid resistance network or a second series liquid resistance network, the first series liquid resistance network includes at least two single liquid resistances connected in series in sequence; the second series liquid resistance network includes at least one single liquid resistance and at least one one-way valve, and all the single liquid resistances and all the one-way valves are connected in series; The parallel liquid resistance network includes a first parallel liquid resistance network or a second parallel liquid resistance network, the first parallel liquid resistance network includes at least two single liquid resistances, and all the single liquid resistances are connected in parallel; the second parallel liquid resistance network includes at least one single liquid resistance and at least one one-way valve, and all the single liquid resistances and all the one-way valves are connected in parallel; The series-parallel liquid resistance network includes a first series-parallel liquid resistance network and a second series-parallel liquid resistance network, the first series-parallel liquid resistance network includes at least three single liquid resistances, and all the single liquid resistances are connected in mixed series; the second series-parallel liquid resistance network includes at least one single liquid resistance and at least one one-way valve, the sum of the number of the single liquid resistances and the one-way valves in the second series-parallel liquid resistance network is not less than 3, and all the single liquid resistances and all the one-way valves are connected in mixed series.

[0012] The present invention also provides a proportional flow valve control method based on the proportional flow valve, comprising the following steps: S1. Determine the preset output flow of the main valve; S2. According to the preset output flow, the preset pilot flow of the pilot valve is obtained by formula 1; according to the preset pilot flow, the pressure difference between the first oil inlet and the first oil outlet of the fluid resistance device is obtained by formula 2; according to the preset pilot flow, the pressure difference between the first oil inlet and the first oil outlet is obtained by formula 3; wherein, formula 1, formula 2 and formula 3 are as follows: q y = q m / [ C dm w m / C ds w s (1+ )] Formula 1 Δ p R = (q y / C dy A R ) 2 ρ / 2Formula 2 F y =Δ p R A + F s + F t Formula 3 in, q y is the preset pilot flow, q m is the preset output flow, C dm is the valve port flow coefficient of the main valve, w m is the valve port area gradient of the main valve, C ds is the flow coefficient of the flow feedback throttling slot, w s is the area gradient of the throttling groove for the flow feedback, x 0 The pre-opening amount of the throttling groove for the flow feedback, x m is the valve core displacement of the main valve, Δ p R is the pressure difference between the first oil inlet and the first oil outlet of the fluid resistance device, C dy is the valve port flow coefficient of the pilot valve, A R is the flow area of ​​the fluid resistance device, ρ is the oil density, F y is the output force of the electromagnetic force output device, A is the effective area at both ends of the valve core of the pilot valve, F s is the hydraulic force of the pilot valve, F t is the spring force of the pilot spring.

[0013] Preferably, it further comprises a damping hole, the main valve has a main oil inlet, the main oil inlet is connected to the main control chamber through the damping hole; the pre-opening amount of the flow feedback throttling groove is 0; S2 also includes: x 0 is equal to 0.

[0014] Preferably, it further comprises a displacement detection device, wherein the displacement detection device is arranged on the pilot valve, and the displacement detection device can detect the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body; S2 also includes: compensating for the influence of the spring force of the pilot spring on the output force of the electromagnetic force output device, the compensation method including: monitoring the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body by the displacement detection device, and obtaining the spring force of the pilot spring according to formula 4; obtaining the magnitude of the output force of the electromagnetic force output device by formulas 1 to 4; wherein formula 4 is as follows: Formula 4 in, F t is the spring force of the pilot spring, k is the spring stiffness of the pilot valve, x 1 is the pre-compression amount of the pilot spring, x y It is the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body.

[0015] Preferably, S2 further includes: compensating for the influence of the hydraulic force of the pilot valve on the output force of the electromagnetic force output device, and the compensation method includes: obtaining the hydraulic force of the pilot valve according to Formula 5; obtaining the magnitude of the output force of the electromagnetic force output device through Formulas 1 to 5; wherein Formula 5 is as follows: Formula 5 in, F s is the hydraulic force of the pilot valve, C v is the flow rate coefficient of the pilot valve, ρ is the oil density, q y To preset the pilot flow, θ is the jet angle of the pilot valve, C dy is the valve port flow coefficient of pilot valve 2, A ( x y ) is the flow area of ​​the pilot valve.

[0016] This embodiment provides a hydraulic control system, which is provided with at least one proportional flow valve as described above.

[0017] Compared with the prior art, the present invention has achieved the following technical effects: The present invention provides a proportional flow valve, a proportional flow valve control method and a hydraulic control system, comprising a fluid resistance device, the fluid resistance device having a first oil inlet and a first oil outlet, the first oil inlet being connected to both the main control chamber and the pilot spring chamber, the first oil outlet being connected to both the pilot oil inlet and the pilot springless chamber, and the pressure of the first oil inlet being greater than the pressure of the first oil outlet. The pilot spring chamber is connected to the first oil inlet, and the pressure of the first oil inlet of the fluid resistance device is introduced into the pilot spring chamber, acting on the left end face of the pilot valve; the pilot springless chamber is connected to the second oil outlet of the fluid resistance device, and the pressure of the second oil outlet is introduced into the pilot springless chamber, acting on the right end face of the pilot valve. The inlet and outlet pressures of the fluid resistance device are converted into a hydraulic pressure acting on the pilot valve core, and the force balance state of the pilot valve core is changed by controlling the output force of the electromagnetic force output device, thereby controlling the inlet and outlet pressure difference of the fluid resistance device, and realizing the flow control of the pilot valve; the flow of the main valve is approximately a linear amplification of the flow of the pilot valve, thereby realizing the control of the flow of the main valve. The present invention changes the flow control method. The flow is a binary function of the valve port area and the valve port pressure difference. The traditional pressure compensator method is to make the pressure difference constant and control the flow by changing the flow area by controlling the valve port opening. However, the pressure compensator is affected by nonlinear factors such as hydraulic force, which makes the pressure difference fluctuate greatly and the flow deviation is large. The present invention adopts a method of fixed flow area and variable pressure difference by setting a fluid resistance device and a corresponding oil circuit design. The flow area of ​​the fluid resistance device is constant. The flow is controlled by changing the inlet and outlet pressure difference of the fluid resistance device through a pilot valve. The flow area of ​​the fluid resistance device will not be affected by other factors. Therefore, as long as the pilot valve is accurately controlled, the output flow of the main valve can be controlled without being affected by load pressure changes. The present invention can make the output flow not affected by load changes under open loop, and has high reliability; the main oil circuit of the present invention does not have a pressure compensator, which simplifies the valve structure, reduces weight, reduces pressure loss, and reduces system energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a common Valvistor valve provided in the background technology; Figure 2 The schematic diagram of the structure of the Valvistor valve provided in the background technology after adding a pressure compensator; Figure 3 A schematic diagram of the structure of the proportional flow valve provided in Example 1; Figure 4 A schematic diagram of the structure of the main valve provided in Example 1; Figure 5 A schematic diagram of the structure of the pilot valve provided in Example 1; Figure 6 A schematic diagram of the structure of a first series liquid resistance network provided in Example 1; Figure 7 Schematic diagram of the structure of the second series liquid resistance network provided in Example 1 Figure 1 ; Figure 8 Schematic diagram of the structure of the second series liquid resistance network provided in Example 1 Figure 2 ; Fig. 9 A schematic diagram of the structure of a first parallel liquid resistance network provided in Example 1; Fig.10 A schematic diagram of the structure of a second parallel liquid resistance network provided in Example 1; Fig.11 A schematic diagram of the structure of a first series-parallel liquid resistance network provided in Example 1; Fig.12 A schematic diagram of the structure of a second series-parallel liquid resistance network provided in Example 1; Fig.13 A schematic diagram of the structure of a third series-parallel liquid resistance network provided in Example 1; Fig.14 A control block diagram of a proportional flow valve control method provided in Example 2; Fig.15 A schematic diagram of the structure of a proportional flow valve provided in Example 3; Fig.16 A schematic diagram of the structure of a gear flow meter provided in Example 3; Fig.17 A schematic diagram of the structure of a worm gear flow meter provided in Example 3; Fig.18 A schematic diagram of the structure of a hydraulic control system provided in Example 4; In the figure: 100, proportional flow valve; 200, hydraulic control system; 1, main valve; 101, main valve core; 102, main valve sleeve; 103, flow feedback throttle groove; 104, return spring; 105, main oil inlet; 106, main oil outlet; 107, main control chamber; 2, pilot valve; 201, pilot valve core; 202, pilot valve body; 203, electromagnetic force output device; 204, pilot spring; 205, pilot spring chamber; 206, pilot oil inlet; 207, pilot oil outlet; 209, pilot springless chamber; 3, displacement detection device; 4, fluid resistance device; 401, first oil inlet; 402, first oil outlet; 403, fluid resistance device; 404, flow meter; 405, flow meter oil inlet; 406, flow meter oil outlet; 407, flow meter spring chamber; 408, flow meter displacement sensor; 409, single fluid resistance; 410, one-way valve; 5, damping hole; 6, reversing valve; 7, pressure compensator. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0021] The object of the present invention is to provide a proportional flow valve, a proportional flow valve control method and a hydraulic control system to solve the problems existing in the above-mentioned prior art, which can control the output flow of the main valve without being affected by changes in load pressure, and has high flow control accuracy; the valve structure is simplified, the weight is reduced, the pressure loss is reduced, and the system energy consumption is reduced.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 like Figure 3-13 As shown, this embodiment provides a proportional flow valve 100, including a main valve 1, a pilot valve 2 and a fluid resistance device 4, wherein: The main valve 1 has a main control chamber 107; The pilot valve 2 includes a pilot valve body 202, a pilot valve core 201, a pilot spring 204 and an electromagnetic force output device 203. The pilot valve core 201 is arranged in the pilot valve body 202 and can separate the pilot valve body 202 into a pilot spring chamber 205 and a pilot spring-free chamber 209. The pilot spring 204 is arranged in the pilot spring chamber 205. The pilot spring 204 can abut against the pilot valve core 201. The electromagnetic force output device 203 is arranged on a side of the pilot valve core 201 away from the pilot spring 204. The electromagnetic force output device 203 can drive the pilot valve core 201 to move along the center line of the valve core hole of the pilot valve body 202 through electromagnetic force. The pilot valve body 202 is provided with a pilot oil inlet 206. The fluid resistance device 4 has a first oil inlet 401 and a first oil outlet 402. The first oil inlet 401 is connected to the main control chamber 107 and the pilot spring chamber 205. The first oil outlet 402 is connected to the pilot oil inlet 206 and the pilot springless chamber 209. The pressure of the first oil inlet 401 is greater than the pressure of the first oil outlet 402.

[0024] The pilot spring chamber 205 is communicated with the first oil inlet 401, and the pressure of the first oil inlet 401 of the fluid resistance device 4 is introduced into the pilot spring chamber 205, acting on the left end face of the pilot valve 2; the pilot springless chamber 209 is communicated with the first oil outlet 402 of the fluid resistance device 4, and the pressure of the first oil outlet 402 is introduced into the pilot springless chamber 209, acting on the left end face of the pilot valve 2. Figure 3 The right end surface of the pilot valve 2 shown in FIG. The inlet and outlet pressures of the fluid resistance device 4 are converted into hydraulic pressure acting on the pilot valve core 201. By controlling the output force of the electromagnetic force output device 203, the force balance state of the pilot valve core 201 is changed, and then the inlet and outlet pressure difference of the fluid resistance device is controlled to achieve the flow control of the pilot valve 2. This embodiment changes the flow control method. The flow is a binary function of the valve port area and the valve port pressure difference. The traditional method of setting the pressure compensator 7 is to make the pressure difference constant and control the flow by changing the flow area by controlling the valve port opening. However, the pressure compensator 7 is affected by nonlinear factors such as hydraulic force, which makes the pressure difference fluctuate greatly and the flow deviation is large. However, this embodiment adopts a method of fixed flow area and variable pressure difference by setting the fluid resistance device 4 and the corresponding oil circuit design. The flow area of ​​the fluid resistance device 4 is constant. The flow is controlled by changing the inlet and outlet pressure difference of the fluid resistance device 4 through the pilot valve 2. The flow area of ​​the fluid resistance device 4 will not be affected by other factors. Therefore, as long as the pilot valve 2 is accurately controlled, the output flow of the main valve 1 can be controlled without being affected by the load pressure change. This embodiment can make the output flow rate not be affected by load changes under open loop, and has high reliability; the main oil circuit of this embodiment does not have a pressure compensator 7, which simplifies the valve structure, reduces weight, reduces pressure loss, and reduces system energy consumption.

[0025] The detailed working principle of this embodiment is as follows: The force balance state of the pilot valve core 201 is:

[0026] The pressure difference Δ between the first oil inlet 401 and the first oil outlet 402 of the fluid resistance device 4 is obtained by formula transformation: p R for:

[0027] When the spring force and hydraulic force of the pilot valve 2 are ignored, the pressure difference Δ of the fluid resistance device 4 p R It is only determined by the output force of the electromagnetic force output device 203 of the pilot valve 2 and has nothing to do with the size of the load pressure.

[0028] The flow area of ​​the fluid resistance device 4 is constant A R , the pilot flow is:

[0029] In summary, when the spring force and hydraulic force of the pilot valve 2 are ignored, the pilot flow rate is only determined by the output force of the electromagnetic force output device 203 of the pilot valve 2 and has nothing to do with the magnitude of the load pressure.

[0030] By controlling the output force of the electromagnetic force output device 203 F y , the pressure difference of the fluid resistance device 4 can be adjusted to control the pilot flow, and it is not affected by the load change. Then, the output flow of the main valve 1 can be controlled without being affected by the load pressure change by using the amplification relationship between the output flow of the main valve 1 and the flow of the pilot valve 2. The amplification relationship between the output flow of the main valve 1 and the flow of the pilot valve 2 is:

[0031] in, p E is the pressure of the first oil inlet 401 of the fluid resistance device 4, p F is the pressure of the first oil outlet 402 of the fluid resistance device 4, F y is the electromagnet output force, q y To preset the pilot flow, q m To preset the output flow, C dy is the valve port flow coefficient of pilot valve 2, C dm is the valve port flow coefficient of main valve 1, w mis the valve port area gradient of main valve 1, C ds is the flow coefficient of the flow feedback throttling slot 103, w s is the area gradient of the flow feedback throttling groove 103, x 0 The pre-opening amount of the flow feedback throttling groove 103, x m is the valve core displacement of main valve 1, Δ p R is the pressure difference between the first oil inlet 401 and the first oil outlet 402 of the fluid resistance device 4, A R is the flow area of ​​the fluid resistance device 4, ρ is the oil density, F y is the output force of the electromagnetic force output device 203, A is the effective area at both ends of the valve core of pilot valve 2, f s is the hydraulic force of pilot valve 2, F t is the spring force of the pilot spring 204 .

[0032] In this embodiment, a damping hole 5 is also included, and the main valve 1 has a main oil inlet 105, which is connected to the main control chamber 107 through the damping hole 5; a flow feedback throttle groove 103 is provided on the main valve 1, and the pre-opening amount of the flow feedback throttle groove 103 is 0. The pre-opening amount refers to the amount of the flow feedback throttle groove 103 of the main valve 1 that is opened in advance. The pre-opening of the flow feedback throttle groove 103 will affect the amplification relationship between the flow of the pilot valve 2 and the main valve 1, so that the flow of the main valve 1 and the flow of the pilot valve 2 are not in a constant amplification relationship. Even if the pilot flow is controlled with high precision, it is difficult to achieve accurate control of the flow of the main valve 1, which affects the flow control accuracy. The larger the pre-opening, the greater the impact, and often requires complex control algorithms for compensation. In this embodiment, the pre-opening of the flow feedback throttle groove 103 is replaced by the damping hole 5, and the pre-opening of the flow feedback throttle groove 103 is set to 0. Through a simple physical structure, the influence of the pre-opening amount of the flow feedback throttle groove 103 on the flow control is eliminated without the need for complex algorithms.

[0033] In this embodiment, a displacement detection device 3 is further included. The displacement detection device 3 is arranged on the pilot valve 2. The displacement detection device 3 can detect the displacement of the pilot valve core 201 along the center line of the valve core hole of the pilot valve body 202. By detecting the displacement of the pilot valve core 201 by the displacement detection device 3, the spring force of the pilot spring 204 and the hydraulic force of the pilot valve 2 can be obtained, so as to compensate for the influence of the spring force and the hydraulic force on the pilot flow, and then compensate for the influence of the spring force and the hydraulic force on the flow of the main valve 1, thereby improving the flow control accuracy.

[0034] In this embodiment, the fluid resistance device 4 is a liquid resistance device 403. As a pure mechanical component, the liquid resistance device 403 is not easy to be damaged, and overcomes the machine safety problem caused by the failure of the pressure sensor.

[0035] In this embodiment, the liquid resistance device 403 is a single liquid resistance 409 or a liquid resistance network; the liquid resistance network is a series liquid resistance network, a parallel liquid resistance network or a series-parallel liquid resistance network; the series liquid resistance network includes a first series liquid resistance network or a second series liquid resistance network, the first series liquid resistance network includes at least two single liquid resistances 409 connected in series in sequence; the second series liquid resistance network includes at least one single liquid resistance 409 and at least one one-way valve 410, and all single liquid resistances 409 are connected in series with all one-way valves 410. The parallel liquid resistance network includes a first parallel liquid resistance network or a second parallel liquid resistance network, the first parallel liquid resistance network includes at least two single liquid resistances 409, and all the single liquid resistances 409 are connected in parallel; the second parallel liquid resistance network includes at least one single liquid resistance 409 and at least one one-way valve 410, and all the single liquid resistances 409 and all the one-way valves 410 are connected in parallel; the series-parallel liquid resistance network includes a first series-parallel liquid resistance network and a second series-parallel liquid resistance network, the first series-parallel liquid resistance network includes at least three single liquid resistances 409, and all the single liquid resistances 409 are connected in mixed series; the second series-parallel liquid resistance network includes at least one single liquid resistance 409 and at least one one-way valve 410, the sum of the number of single liquid resistances 409 and one-way valves 410 in the second series-parallel liquid resistance network is not less than 3, and the single liquid resistances 409 and the one-way valves 410 are connected in mixed series.

[0036] As a preferred embodiment, the first series liquid resistance network includes two single liquid resistances 409 in series, the second series liquid resistance network includes a single liquid resistance 409 in series and a one-way valve 410; the first parallel liquid resistance network includes two single liquid resistances 409 in parallel, the second parallel liquid resistance network includes a single liquid resistance 409 in parallel and a one-way valve 410; the first series-parallel liquid resistance network includes a single liquid resistance 409 in parallel and a second series liquid resistance network, the second series-parallel liquid resistance network includes a single liquid resistance 409 in parallel and the first series liquid resistance network, and the third series-parallel liquid resistance network includes a single liquid resistance 409 in series and the first parallel liquid resistance network. The liquid resistance device 403 of this embodiment can be Figure 6-13 Any of the fluid resistance networks shown may be a single fluid resistance 409, or a fluid resistance network composed of multiple fluid resistances and one-way valves 410 connected in series, or a fluid resistance network composed of multiple fluid resistances and one-way valves 410 connected in parallel, or a fluid resistance network composed of multiple fluid resistances and one-way valves 410 connected in series and in parallel. It should be noted that the fluid resistance device 403 of this embodiment is not limited to Figure 6-13 The form shown, a hydraulic resistance network formed by any combination of multiple hydraulic resistances and one-way valves 410 is applicable to this embodiment.

[0037] In this embodiment, Figure 4 As shown, the main valve 1 is preferably a main cartridge valve, and the main valve 1 includes a main valve core 101 , a main valve sleeve 102 , a return spring 104 , a main oil inlet 105 , and a main oil outlet 106 .

[0038] In this embodiment, Figure 5 As shown, the electromagnetic force output device 203 is a proportional electromagnet, which can be one of a one-way proportional electromagnet and a two-way proportional electromagnet, and the displacement detection device 3 is a displacement sensor. The pilot valve 2 also has a pilot oil outlet 207. The displacement sensor can be installed on the pilot valve core 201, or can be installed on the side of the proportional electromagnet, or can be installed on the side of the spring chamber. The damping hole 5 can be set on the pilot valve body 202, or on the valve core.

[0039] The basic working process of the proportional flow valve 100 of this embodiment is: in the initial position, the proportional solenoid is not energized, the pilot valve 2 port is closed, the pre-opening amount of the flow feedback throttling groove 103 is 0, the main control chamber 107 of the main valve 1 and the main oil inlet 105 of the main valve 1 are connected through the damping hole 5, the pressure is equal, and the main valve core 101 is in a closed state due to the upper and lower area difference and the return spring 104; when the pilot valve port is opened, the pressure in the main control chamber 107 of the main valve 1 is reduced, and the main valve core 101 moves upward until the flow through the flow feedback throttling groove 103 and the pilot valve 2 is equal, and the main valve core 101 stops moving; the flow of the main valve core 101 is a linear amplification of the flow of the pilot valve 2.

[0040] Example 2 This embodiment provides a proportional flow valve 100 control method based on the proportional flow valve 100 of embodiment 1, comprising the following steps: S1, determine the preset output flow of main valve 1; S2. According to the preset output flow, the preset pilot flow of the pilot valve 2 is obtained through formula 1; according to the preset pilot flow, the pressure difference between the first oil inlet 401 and the first oil outlet 402 of the fluid resistance device 4 is obtained through formula 2; according to the preset pilot flow, the pressure difference between the first oil inlet 401 and the first oil outlet 402, the output force of the electromagnetic force output device 203 is obtained through formula 3; formula 1, formula 2 and formula 3 are as follows: q y = q m / [ C dm w m / C ds ws (1+ )] Formula 1 Δ p R = (q y / C dy A R ) 2 ρ / 2Formula 2 F y =Δ p R A + F s + F t Formula 3 in, q y To preset the pilot flow, q m To preset the output flow, C dm is the valve port flow coefficient of main valve 1, w m is the valve port area gradient of main valve 1, C ds is the flow coefficient of the flow feedback throttling slot 103, w s is the area gradient of the flow feedback throttling groove 103, x 0 The pre-opening amount of the flow feedback throttling groove 103, x m is the valve core displacement of main valve 1, Δ p R is the pressure difference between the first oil inlet 401 and the first oil outlet 402 of the fluid resistance device 4, C dy is the valve port flow coefficient of pilot valve 2, A R is the flow area of ​​the fluid resistance device 4, ρ is the oil density, F y is the output force of the electromagnetic force output device 203, A is the effective area at both ends of the valve core of pilot valve 2, F s is the hydraulic force of pilot valve 2, F t is the spring force of the pilot spring 204 .

[0041] In this embodiment, the damping hole 5 is also included, the main valve 1 has a main oil inlet 105, and the main oil inlet 105 is connected to the main control chamber 107 through the damping hole 5; the pre-opening amount of the flow feedback throttle groove 103 is 0; S2 also includes: x 0 Equal to 0. In this embodiment, by setting the damping hole 5, the pre-opening amount of the flow feedback throttling groove 103 is set to 0, so that the amplification relationship between the pilot flow and the flow of the main valve 1 is not affected by the pre-opening amount, so that when the output force of the electromagnetic force output device 203 is used to control the flow of the main valve 1, it can be unaffected by the pre-opening amount, thereby improving the control accuracy.

[0042] As a feasible implementation, the influence of the hydraulic force of the pilot valve 2 and the spring force of the pilot spring 204 is ignored, that is, the hydraulic force of the pilot valve 2 and the spring force of the pilot spring 204 are both 0, and the magnitude of the output force of the electromagnetic force output device 203 is obtained by formula 3 according to the preset pilot flow rate and the pressure difference between the first oil inlet 401 and the first oil outlet 402. When the proportional flow valve 100 is controlled by the implementation, the output flow of the main valve 1 can be controlled without being affected by the load pressure change, but the accuracy is low because the hydraulic force of the pilot valve 2 and the spring force of the pilot spring 204 are not compensated.

[0043] In this embodiment, a displacement detection device 3 is also included. The displacement detection device 3 is arranged on the pilot valve 2. The displacement detection device 3 can detect the displacement of the pilot valve core 201 along the center line of the valve core hole of the pilot valve body 202. S2 also includes: compensating for the influence of the spring force of the pilot spring 204 on the output force of the electromagnetic force output device 203, the compensation method includes: monitoring the displacement of the pilot valve core 201 along the center line of the valve core hole of the pilot valve body 202 by the displacement detection device 3, and obtaining the spring force of the pilot spring 204 according to formula 4; obtaining the magnitude of the output force of the electromagnetic force output device 203 by formulas 1 to 4; formula 4 is as follows: Formula 4 in, F t is the spring force of the pilot spring 204, k is the spring stiffness of pilot valve 2, x 1 is the pre-compression amount of the pilot spring 204, x y is the displacement of the pilot valve core 201 along the center line of the valve core hole of the pilot valve body 202. The pre-compression amount of the pilot spring 204 is predetermined. By detecting the displacement of the pilot valve core 201 along the center line of the valve core hole of the pilot valve body 202, the length of the pilot spring 204 can be obtained, thereby obtaining the spring force of the pilot spring 204. Substituting Formula 4 into Formula 3, the output force after spring force compensation can be obtained.

[0044] In this embodiment, S2 also includes: compensating for the influence of the hydraulic force of the pilot valve 2 on the output force of the electromagnetic force output device 203, and the compensation method includes: obtaining the hydraulic force of the pilot valve 2 according to Formula 5; obtaining the magnitude of the output force of the electromagnetic force output device 203 through Formulas 1 to 5, that is, the output force after the spring force and the hydraulic force are compensated can be obtained; wherein Formula 5 is as follows: Formula 5 in, F s is the hydraulic force of pilot valve 2, C v is the flow rate coefficient of pilot valve 2, ρ is the oil density, q y To preset the pilot flow, θ is the jet angle of pilot valve 2, C dy is the valve port flow coefficient of pilot valve 2, A ( x y ) is the flow area of ​​the pilot valve 2. Substituting formulas 4 and 5 into formula 3, the output force after the spring force and the hydraulic force compensation can be obtained, which can further improve the control accuracy of the inlet and outlet pressure difference of the fluid resistance device 4, thereby improving the flow control accuracy.

[0045] As a preferred implementation, the proportional flow valve 100 control method provided in this embodiment includes the following steps: Step 1: Convert the required output flow rate (preset output flow rate) of the main valve 1 into a function of the inlet and outlet pressure difference of the fluid resistance device 4 through formula 1 and formula 2, and give the command signal Δ p a Specifically: let the pre-opening volume in formula 1 be 0; obtain the preset pilot flow q y , and then use the preset pilot flow q y The pressure difference between the first oil inlet 401 and the first oil outlet 402 of the fluid resistance device 4 is obtained by formula 2, and the command signal Δ p a ; Step 2: Set the command signal Δ p a Converted into the output force of the proportional solenoid F a , that is, Δ in step 1 p a Substitute into formula 3; Step 3: Synchronously detect the displacement of the pilot valve core 201 through the displacement detection device 3x y , according to the formula Calculate the spring force of the pilot spring 204; Step 4: Based on the detected displacement of the pilot valve core 201 x y and preset pilot flow q y , obtain the hydraulic force of pilot valve 2 F s ;

[0046] Step 5: Superimpose the obtained hydraulic force and spring force on the output force command signal of the proportional solenoid, that is, obtain the corrected command output force through formula 3 F b , and input it into the signal processing module; Step 6: The signal processing module outputs the force output voltage signal according to the correction instruction u b To the proportional amplifier, which in turn controls the proportional solenoid to output electromagnetic force, thereby achieving flow control of main valve 1.

[0047] Example 3 This embodiment provides a proportional flow valve 100, such as Figure 15-17 As shown, the fluid resistance device 4 is replaced by a flow meter 404 by a fluid resistance device 403. Except for the fluid resistance device 4, the other structures and working principles of this embodiment are the same as those of embodiment 1. The control method of the proportional flow valve 100 of this embodiment is the same as that of embodiment 2.

[0048] In this embodiment, the flowmeter 404 is provided with a flowmeter oil inlet 405, a flowmeter oil outlet 406, a flowmeter spring chamber 407, and a flowmeter displacement detection device (such as a flowmeter displacement sensor 408). The flowmeter oil inlet 405 is the first oil inlet 401 of the fluid resistance device 4, the flowmeter oil outlet 406 is the first oil outlet 402 of the fluid resistance device 4, and the flowmeter oil outlet 406 is also connected to the flowmeter spring chamber 407. The pilot spring chamber 205 is connected to the flow meter oil inlet 405, and the pressure of the flow meter oil inlet 405 is introduced into the pilot spring chamber 205, acting on the left end face of the pilot valve 2. The pilot springless chamber 209 is connected to the flow meter oil outlet 406, and the pressure of the flow meter oil outlet 406 is introduced into the pilot springless chamber 209, acting on the right end face of the pilot valve 2, and the inlet and outlet pressures of the flow meter 404 are converted into the hydraulic pressure acting on the pilot valve core 201. By controlling the output force of the electromagnetic force output device 203, the force balance state of the pilot valve core 201 is changed, and then the inlet and outlet pressure difference of the flow meter 404 is controlled to achieve pilot flow control. At the same time, based on the flow meter displacement sensor 408, the pilot flow that the flow meter 404 can detect in real time can be used to achieve closed-loop high-precision control of the pilot flow, and then the amplification relationship between the output flow of the main valve 1 and the flow of the pilot valve 2 is used to achieve high-precision control of the flow of the main valve 1.

[0049] like Fig.16 and 17 As shown, the flow meter 404 in this embodiment can be a throttling flow meter 404, a gear flow meter 404, a turbine flow meter 404, etc.

[0050] Example 4 like Fig.18 As shown, this embodiment provides a hydraulic control system 200, which is provided with at least one proportional flow valve 100 of any one of Embodiment 1, and / or at least one proportional flow valve 100 of any one of Embodiment 3. In this embodiment, the proportional flow valve 100 is applied to the multi-way valve hydraulic control system 200, and the proportional flow valve 100 realizes flow regulation of the hydraulic control system 200.

[0051] In this embodiment, a reversing valve 6 is also included, and a proportional flow valve 100 is connected in series at the inlet and outlet of the reversing valve 6 to perform valve port independent flow / pressure control. During operation, the oil enters from the P port of the proportional flow valve 100 connected to the oil inlet of the reversing valve 6, and the flow is controlled by the proportional flow valve 100 on the oil inlet side; after the reversing valve 6, the oil flows into the actuator, and the oil in the other chamber of the actuator flows into the oil tank through the reversing valve 6 and the proportional flow valve 100 on the oil return side, forming a series circuit. Similarly, the proportional flow valve 100 on the oil return side can also perform flow control. The hydraulic control system 200 of this embodiment is a valve port independent control type multi-way valve system, which retains the traditional reversing valve 6, so that the system has two functions of independence and linkage. Not only can the valve port be independently controlled, but also four-side linkage control can be performed through the reversing valve 6. It can be applied to valve port independent systems, load sensitive systems, positive flow systems, and negative flow systems. It has good versatility and compatibility, and good flow control characteristics.

[0052] In this embodiment, the reversing valve 6 is in the form of a sliding valve, and the proportional flow valve 100 is in the form of a cartridge valve, which combines the advantages of the sliding valve and the cartridge valve. The sliding valve has good micro-motion characteristics, and the cartridge valve has low pressure loss and strong flow capacity, thereby taking into account low pressure loss, large flow control and fine small flow control.

[0053] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A proportional flow valve, characterized in that: It includes a main valve, a pilot valve and a fluid resistance device, wherein: The main valve has a main control chamber; The pilot valve comprises a pilot valve body, a pilot valve core, a pilot spring and an electromagnetic force output device, wherein the pilot valve core is arranged in the pilot valve body and can separate the pilot valve body into a pilot spring chamber and a pilot springless chamber, the pilot spring is arranged in the pilot spring chamber, the pilot spring can abut against the pilot valve core, the electromagnetic force output device is arranged on a side of the pilot valve core away from the pilot spring, and the electromagnetic force output device can drive the pilot valve core to move along the center line of the valve core hole of the pilot valve body by electromagnetic force; the pilot valve body is provided with a pilot oil inlet; The fluid resistance device has a first oil inlet and a first oil outlet, the first oil inlet is connected to both the main control chamber and the pilot spring chamber, the first oil outlet is connected to both the pilot oil inlet and the pilot springless chamber, and the pressure of the first oil inlet is greater than the pressure of the first oil outlet.

2. The proportional flow valve according to claim 1, characterized in that: It also includes a damping hole, the main valve has a main oil inlet, the main oil inlet is connected to the main control chamber through the damping hole; a flow feedback throttling groove is provided on the main valve, and the pre-opening amount of the flow feedback throttling groove is 0.

3. The proportional flow valve according to claim 1, characterized in that: It also includes a displacement detection device, which is arranged on the pilot valve and can detect the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body.

4. The proportional flow valve according to claim 1, characterized in that: The fluid resistance device is a liquid resistance device or a flow meter.

5. The proportional flow valve according to claim 4, characterized in that: The liquid resistance device is a single liquid resistance or a liquid resistance network; the liquid resistance network is a series liquid resistance network, a parallel liquid resistance network or a series-parallel liquid resistance network; the series liquid resistance network includes a first series liquid resistance network or a second series liquid resistance network, the first series liquid resistance network includes at least two single liquid resistances connected in series in sequence; the second series liquid resistance network includes at least one single liquid resistance and at least one one-way valve, and all the single liquid resistances and all the one-way valves are connected in series; The parallel liquid resistance network includes a first parallel liquid resistance network or a second parallel liquid resistance network, the first parallel liquid resistance network includes at least two single liquid resistances, and all the single liquid resistances are connected in parallel; the second parallel liquid resistance network includes at least one single liquid resistance and at least one one-way valve, and all the single liquid resistances and all the one-way valves are connected in parallel; The series-parallel liquid resistance network includes a first series-parallel liquid resistance network and a second series-parallel liquid resistance network, the first series-parallel liquid resistance network includes at least three single liquid resistances, and all the single liquid resistances are connected in mixed series; the second series-parallel liquid resistance network includes at least one single liquid resistance and at least one one-way valve, the sum of the number of the single liquid resistances and the one-way valves in the second series-parallel liquid resistance network is not less than 3, and all the single liquid resistances and all the one-way valves are connected in mixed series.

6. A proportional flow valve control method based on the proportional flow valve according to any one of claims 1 to 5, characterized in that: The steps include: S1. Determine the preset output flow of the main valve; S2. Obtaining a preset pilot flow of the pilot valve according to the preset output flow by using Formula 1; Obtaining the pressure difference between the first oil inlet and the first oil outlet of the fluid resistance device according to the preset pilot flow rate through Formula 2; The magnitude of the output force of the electromagnetic force output device is obtained by formula 3 according to the preset pilot flow and the pressure difference between the first oil inlet and the first oil outlet; wherein formula 1, formula 2 and formula 3 are as follows: q y = q m / [ C dm w m / C ds w s (1+ )] Official 1 Δ p R = (q y / C dy A R ) 2 ρ / 2 Formula 2 F y =Δ p R A + F s + F t Formula 3 in, q y is the preset pilot flow, q m is the preset output flow, C dm is the valve port flow coefficient of the main valve, w m is the valve port area gradient of the main valve, C ds is the flow coefficient of the flow feedback throttling slot, w s is the area gradient of the throttling groove for the flow feedback, x 0 is the pre-opening amount of the flow feedback throttling groove, x m is the valve core displacement of the main valve, Δ p R is the pressure difference between the first oil inlet and the first oil outlet of the fluid resistance device, C dy is the valve port flow coefficient of the pilot valve, A R is the flow area of ​​the fluid resistance device, ρ is the oil density, F y is the output force of the electromagnetic force output device, A is the effective area at both ends of the valve core of the pilot valve, F s is the hydraulic force of the pilot valve, F t is the spring force of the pilot spring.

7. The proportional flow valve control method according to claim 6, characterized in that: It also includes a damping hole, the main valve has a main oil inlet, and the main oil inlet is connected to the main control chamber through the damping hole; The pre-opening amount of the flow feedback throttling groove is 0; S2 also includes: x 0 is equal to 0.

8. The proportional flow valve control method according to claim 7, characterized in that: It also includes a displacement detection device, which is arranged on the pilot valve and can detect the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body; S2 also includes: compensating for the influence of the spring force of the pilot spring on the output force of the electromagnetic force output device, the compensation method including: monitoring the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body by the displacement detection device, and obtaining the spring force of the pilot spring according to formula 4; obtaining the magnitude of the output force of the electromagnetic force output device by formulas 1 to 4; wherein formula 4 is as follows: Equation 4 in, F t is the spring force of the pilot spring, k is the spring stiffness of the pilot valve, x 1 is the pre-compression amount of the pilot spring, x y It is the displacement of the pilot valve core along the center line of the valve core hole of the pilot valve body.

9. The proportional flow valve control method according to claim 7 or 8, characterized in that: S2 also includes: compensating for the influence of the hydraulic force of the pilot valve on the output force of the electromagnetic force output device, and the compensation method includes: obtaining the hydraulic force of the pilot valve according to Formula 5; obtaining the magnitude of the output force of the electromagnetic force output device through Formulas 1 to 5; wherein Formula 5 is as follows: Formula 5 in, F s is the hydraulic force of the pilot valve, C v is the flow rate coefficient of the pilot valve, ρ is the oil density, q y To preset the pilot flow, θ is the jet angle of the pilot valve, C dy is the valve port flow coefficient of pilot valve 2, A ( x y ) is the flow area of ​​the pilot valve.

10. A hydraulic control system, characterized in that: At least one proportional flow valve as claimed in any one of claims 1 to 5 is provided.

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