Flow valve, flow control module and hydraulic system

Abstract

The invention provides a flow valve, a flow control module comprising the flow valve and a hydraulic system, a first containing cavity, a second containing cavity, a third containing cavity and corresponding outlets are arranged, a variable opening channel is arranged between the first containing cavity and the second containing cavity, and a variable opening channel is arranged between the first containing cavity C1 and the third containing cavity; in the working state, hydraulic oil enters the flow valve from the first oil port to push away the valve element and flows out from the second oil port and the third oil port, and the second oil port can be communicated with the third oil port. Certain pressure differences are generated at the damping channels of the first containing cavity and the second containing cavity, the damping channels of the first containing cavity and the third containing cavity and the third oil port through which hydraulic oil flows, and in the steady state, the corresponding opening position of the valve element can be kept balanced. Under the condition of a certain pressure difference, the opening degree of the third oil port is controlled through the pilot valve, and accurate control over the flow is achieved.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202210865733.6, with an application date of July 21, 2022, and a title of "A Flow Valve, a Flow Control Module and a Hydraulic System". Technical Field

[0002] The present invention relates to the field of hydraulic flow control, and particularly to a flow valve, a flow control module and a hydraulic system. Background Art

[0003] Flow rate is an important control parameter in a hydraulic system and is a direct way to achieve speed control of a hydraulic-driven load. With the continuous improvement of the automation and intelligence levels of hydraulic drive control, traditional mechanically set flow valves can no longer meet the usage requirements of real-time speed adjustment of the load. In recent years, proportional flow control technology has made great progress. Currently, world-renowned hydraulic component manufacturers have all launched proportional multi-way valve system products that integrate circuit pressure, flow rate and direction control. However, the proportional multi-way valve has a complex structure, and the products of each manufacturer form their own systems with poor universality, resulting in a high cost of the proportional multi-way valve. In addition, due to the limitation of the power of the pilot stage and the space limitation of the pilot circuit, the frequency response of the pilot-operated proportional multi-way valve is not high; for the direct-acting proportional multi-way valve, although its frequency response is higher than that of the pilot-operated proportional multi-way valve, restricted by the thrust characteristics of the electromagnetic coil, its power range is small. Currently, existing proportional multi-way valves cannot meet the working condition requirements of high-power control with adjustable buffering and fast start-stop, such as large logging machines. Their automatic feeding action has a short action time, a large working flow rate, a feeding speed reaching 4 - 6 m / s, and a feeding position control accuracy requirement reaching the centimeter level. The entire feeding action needs to be completed within 0.6 s, which poses high requirements for the start-stop control and buffering performance of the valve. Existing multi-way valves cannot meet this control requirement. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a flow valve with precise flow control, including a valve core, a first cavity C1, a second cavity C2 and a third cavity C3, a first oil port Y1, a second oil port Y2 and a third oil port Y3. The first cavity C1 is communicated with the first oil port Y1, the second cavity C2 is communicated with the second oil port Y2, and the third cavity C3 is communicated with the third oil port Y3. It is characterized in that a variable opening channel T1 is provided between the first cavity C1 and the second cavity C2, and a variable opening channel T2 is provided between the first cavity C1 and the third cavity C3; a return spring is further included in the third cavity C3. When the flow valve is in a non-working state, the return spring can keep the valve core in an initial state; when the flow valve is in a working state, the valve core opens the variable opening channels T1 and T2, and the third oil port Y3 is the active control outlet. By controlling the flow area of the third oil port Y3, the opening degree of the valve core can be controlled.

[0005] Preferably, the flow area of the third oil port Y3 is controlled by a pilot valve.

[0006] Preferably, the second oil port Y2 is in communication with the third oil port Y3.

[0007] Preferably, A1 + A2 = A3, where A1 is the acting area of the pressure in the first chamber C1 on the spool, A2 is the acting area of the pressure in the second chamber C2 on the spool, and A3 is the acting area of the pressure in the third chamber C3 on the spool.

[0008] Preferably, ΔP = ΔP1 + ΔP2, where ΔP is the pressure difference between the first chamber C1 and the second chamber C2; ΔP1 is the pressure difference generated between the first chamber C1 and the third chamber C3, and ΔP2 is the pressure difference generated by flowing through the third oil port Y3.

[0009] Preferably, the flow area S of the third oil port Y3 y has the following relationship with the spool opening x:

[0010]

[0011] where A1 is the acting area A1 of the pressure in the first chamber C1 on the spool, A2 is the acting area of the pressure in the second chamber C2 on the spool, x is the displacement of the spool, ΔP is the pressure difference between the first chamber C1 and the second chamber C2; g(x) is the flow area of the valve port of the passage between the first chamber C1 and the second chamber C3; F x is the restoring force of the flow control valve spring.

[0012] Preferably, the acting force F of the return spring x is made small enough on the premise of keeping the spool in the initial state. x Sufficiently small.

[0013] Preferably, the acting area A1 of the pressure in the first chamber C1 on the spool is equal to the acting area A2 of the pressure in the second chamber C2 on the spool.

[0014] The present invention also provides a flow control module, which includes the above flow control valve.

[0015] The present invention also provides a hydraulic system, which includes the above flow control valve and the above flow control module. Compared with the prior art, the beneficial technical effects of the present invention are as follows: providing a flow control valve, a flow control module and a hydraulic system to achieve precise control of the flow rate, controlling the initial state of the flow control valve by setting the first chamber C1, the second chamber C2 and the third chamber C3 and the return spring, and achieving pressure difference balance during the working process, and controlling the opening of the spool by controlling the flow area of the third oil port in the third chamber C3. Brief Description of the Drawings

[0016] Figure 1 This is a schematic structural diagram of the flow valve of the present invention;

[0017] Figure 2 This is the schematic diagram of the principle of the flow valve of the present invention;

[0018] Figure 3 This is the schematic diagram of the principle of the flow valve of another embodiment of the present invention;

[0019] Figure 4 This is the schematic diagram of the principle of the constant differential pressure overflow flow control module of the present invention;

[0020] Figure 5 This is the schematic diagram of the principle of the pressure compensation flow control module of the present invention;

[0021] Figure 6 This is the schematic diagram of the principle of the load feedback flow control module of the present invention;

[0022] Figure 7 This is the schematic diagram of the principle of the pressure compensation and load feedback module flow control module of the present invention;

[0023] Figure 8 This is the schematic diagram of the principle of the chain flow control module of the present invention;

[0024] Figure 9 This is the schematic diagram of the principle of the flow direction control module of the present invention;

[0025] Figure 10 This is the schematic diagram of the principle of the chain flow direction control module of the present invention;

[0026] Figure 11 This is the fixed-displacement hydraulic system of the present invention;

[0027] Figure 12 This is the variable-displacement hydraulic system of the present invention. Detailed Description of the Invention

[0028] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0029] Such as Figures 1-3As shown in the figure, this embodiment provides a flow valve, which has a first cavity C1, a second cavity C2, a third cavity C3, a first oil port Y1, a second oil port Y2, and a third oil port Y3. The first cavity C1 is communicated with the first oil port, the second cavity C2 is communicated with the second oil port, and the third cavity C3 is communicated with the third oil port. A variable-opening damping channel T1 is provided between the first cavity C1 and the second cavity C2 for communication. The first cavity C1 is communicated with the third cavity C2 through a damping channel T2 related to the spool position on the spool, and the opening of the damping channel T2 is related to the position of the spool. A feedback spring is arranged in the third cavity C3. In the initial state, there is no fluid flow or only a tiny flow in the damping channel between the first cavity C1 and the third cavity C3. The pressure difference generated by this flow on the smallest damping channel does not affect the reset function of the spring. Under the action of the spring, the spool is in the right position, and the first cavity C1 and the second cavity C2 are in a separated state, that is, the first oil port and the second oil port are in a cut-off state. The third oil port Y3 is a damping hole with variable opening, and its opening is controlled by a pilot valve connected thereto (such as a proportional pilot valve). In the working state, the hydraulic oil enters the flow valve from the first oil port Y1 to push the spool open and flows out from the second oil port Y2 and the third oil port Y3, and the second oil port Y2 and the third oil port Y3 can be communicated. Certain pressure differences are generated at the damping channels of the first cavity C1 and the second cavity C2, the first cavity C1 and the third cavity C2, and the third oil port Y3 through which the hydraulic oil flows. At steady state, according to the spool force balance equation, the spool will maintain balance at the corresponding opening position. Under the condition of a certain pressure difference, the opening of the third oil port Y3 is controlled by the pilot valve to achieve the control of the flow valve.

[0030] Specifically, let the acting area of the pressure in the first cavity C1 on the spool be A1, the acting area of the pressure in the second cavity C2 on the spool be A2, the acting area of the pressure in the third cavity C3 on the spool be A3, and the displacement of the spool be x; among them,

[0031] A1 + A2 = A3; (1)

[0032] The valve port excess area S of the channel between the first cavity C1 and the second cavity C2 12 = f(x), the valve port flow area S of the channel between the first cavity C1 and the second cavity C3 13 = g(x); the flow area S of the third oil port Y3 actively controlled by the third cavity y ; The flow rate from the first cavity C1 to the second cavity C2 through S 12 is Q1, and at the same time, a pressure difference is generated between the first cavity C1 and the second cavity C2, that is, the pressure difference when passing through the flow rate Q1 at S 12 is ΔP. The flow from the first cavity C1 to the third cavity C3 through S 13 , and then through the flow area S of the actively controlled third oil port Y3 yThe flow rate is Q2, and at the same time, at S 13 and S y the pressure differences generated are ΔP1 and ΔP2 respectively. Since the second oil port Y2 and the third oil port Y3 are connected and their outlet pressures are equal, we have

[0033] ΔP1 + ΔP2 = ΔP (2)

[0034] For common load-sensitive systems, systems such as load-sensitive valves and flow regulating valves with compensation belong to constant pressure difference speed control systems, and ΔP is a constant.

[0035] For the spool, the restoring force of the flow valve spring is F x ; From the force balance equation, we get:

[0036] PA1 + (P - ΔP)A2 = (P - ΔP1)A3 + Fx (3)

[0037] From the valve port flow formula, we get:

[0038] At T2:

[0039] At Y3:

[0040] From (1) to (5), we get

[0041]

[0042] As can be seen from equation (6), in this embodiment, a variable damping channel related to the spool displacement is provided on the spool, thereby establishing a strong correlation correspondence between the opening of the spool and the flow area S y of the active control outlet Y3. By controlling the variable y, the flow area S y of the active control outlet Y3 is controlled, and then the opening x of the spool of this flow valve is controlled, thereby realizing the flow control of the constant pressure difference flow control system.

[0043] At this time, the total flow rate through the valve: Q = Q1 + Q2, that is:

[0044]

[0045] In the flow valve, the function of the return spring is to provide a definite initial position state for the spool. At the same time, the spring force will also cause a spring force single quantity pressure loss: ΔP F = F x / A3. Therefore, on the premise of meeting the requirement of providing a definite initial state of the spool, the smaller the spring force, the better.

[0046] Usually F x << ΔPA1, F x << ΔPA2, so equation (6) can be simplified to:

[0047]

[0048] When A1 = A2, g(x) = kx + b, where k and b are structural constants of the spool valve, Equation (6) can be further simplified to:

[0049]

[0050] As Figures 4-7 shown, the flow control module includes the above-mentioned flow valve, and also includes a constant-differential overflow module, a pressure compensation module, a load feedback module, or a pressure compensation load feedback module, etc.

[0051] As Figures 8-10 shown, the chain-type flow control module, the flow direction control module, and the chain-type flow direction control module include the above-mentioned flow valve.

[0052] As Figures 10-11 shown, the fixed-displacement hydraulic system and the variable-displacement hydraulic system include the above-mentioned flow valve or flow control module.

[0053] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is 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 should not be construed as a limitation of the present invention.

[0054] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0055] In the present invention, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "fixed", etc. 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art

[0056] The above content is a further detailed description of the present invention in combination with specific implementation manners, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made.

Claims

1. A flow valve, comprising a valve core, a first cavity C1, a second cavity C2, a third cavity C3, a first oil port Y1, a second oil port Y2, and a third oil port Y3. The first cavity C1 is in communication with the first oil port Y1, the second cavity C2 is in communication with the second oil port Y2, and the third cavity C3 is in communication with the third oil port Y3. It is characterized in that A variable opening channel T1 is provided between the first cavity C1 and the second cavity C2, and a variable opening channel T2 is provided between the first cavity C1 and the third cavity C3. The third cavity C3 further includes a return spring. When the flow valve is in a non-operating state, the return spring can keep the valve core in an initial state. When the flow valve is in an operating state, the valve core opens the variable opening channels T1 and T2. The third oil port Y3 is an active control outlet, and the opening of the valve core can be controlled by controlling the flow area of the third oil port Y3.

2. The flow valve according to claim 1, characterized in that, The flow area of the third oil port Y3 is controlled by a pilot valve.

3. A flow valve according to claim 2, characterized in that, The second oil port Y2 is in communication with the third oil port Y3.

4. The flow valve according to claim 3, characterized in that, A1 + A2 = A3, where A1 is the acting area of the pressure in the first cavity C1 on the valve core, A2 is the acting area of the pressure in the second cavity C2 on the valve core, and A3 is the acting area of the pressure in the third cavity C3 on the valve core.

5. A flow valve according to claim 4, characterized in that, ΔP = ΔP1 + ΔP2, where ΔP is the pressure difference between the first cavity C1 and the second cavity C2; ΔP1 is the pressure difference generated between the first cavity C1 and the third cavity C3, and ΔP2 is the pressure difference generated by flowing through the third oil port Y3.

6. A flow valve according to claim 5, characterized in that, The flow area S of the third oil port Y3 y has the following relationship with the spool opening x: Among them, A1 is the acting area A1 of the pressure in the first cavity C1 on the valve core, A2 is the acting area of the pressure in the second cavity C2 on the valve core, x is the displacement of the valve core, ΔP is the pressure difference between the first cavity C1 and the second cavity C2; g(x) is the flow area of the valve port of the channel between the first cavity C1 and the second cavity C3; F x is the restoring force of the flow control valve spring.

7. A flow valve according to claim 6, characterized in that The acting force F of the return spring x On the premise of ensuring that the spool valve remains in the initial state, make F x small enough.

8. A flow valve according to claim 7, wherein, The acting area A1 of the pressure in the first cavity C1 on the valve core is equal to the acting area A2 of the pressure in the second cavity C2 on the valve core.

9. A flow control module, characterized in that, It includes the flow valve according to any one of claims 1-8.

10. A hydraulic system, characterized in that, It includes the flow valve according to any one of claims 1-8 and the flow control module according to claim 9.

Images