Differential valve assembly

Abstract

The application discloses a differential valve assembly and relates to the technical field of differential control of hydraulic oil cylinders. The differential valve assembly comprises a valve body and a logic valve. A conical cavity is provided with a first oil port and a second oil port. The first oil port can be communicated with a first working oil port. The second oil port is communicated with a second communication port. A control oil port is communicated with a second working oil port. When oil enters the first working oil port and oil returns from the second working oil port, oil enters a rodless cavity of a hydraulic oil cylinder through the first working oil port and the first communication port. The rod cavity of the hydraulic oil cylinder returns oil. The returned oil enters the conical cavity through the second communication port and the second oil port. The returned oil of a spring cavity enters the second working oil port through the control oil port. The logic valve is opened. The returned oil of the rod cavity of the hydraulic oil cylinder enters the rodless cavity of the hydraulic oil cylinder through the logic valve and a first one-way valve. The differential of the rodless cavity of the hydraulic oil cylinder is realized. The piston rod is rapidly extended. The working efficiency is improved. The logic valve is detachably arranged on the valve body. The applicable flow is expanded. The cost is low.

Description

Technical Field

[0001] This invention relates to the field of differential control technology for hydraulic cylinders, and more particularly to a differential valve assembly. Background Technology

[0002] In the field of hydraulic engineering machinery, applications often involve the rapid extension of hydraulic cylinders. To improve the efficiency of cylinder extension, a differential circuit is often designed, such as... Figure 1 As shown, the return oil from the small chamber of the hydraulic cylinder 100 is not directly returned to the oil tank, but is returned to the large chamber of the hydraulic cylinder 100 through a series of valve groups, realizing the connection between the large and small chambers. At this time, the area of ​​the pressure oil is the area of ​​the large chamber minus the area of ​​the small chamber. Due to the area difference, the piston rod extends, and the volume that needs to be supplemented for the piston rod to extend becomes the volume of the piston rod. Under the same oil supply capacity, the extension speed of the piston rod is greatly increased.

[0003] Currently, the valve assemblies used in differential circuits are generally two-position three-way valves, and the hydraulic circuits are as follows: Figure 1 As shown, when the piston rod extends, it operates in the right position, with oil port 1 and oil port 3 connected. Pressure oil enters the large chamber of hydraulic cylinder 100. Due to the area difference between the large and small chambers, the piston rod extends, and oil returns from the small chamber to the large chamber, achieving differential operation. When the piston rod retracts, it operates in the left position, with oil port 2 and oil port 3 connected. Pressure oil enters the small chamber, and oil returns from the large chamber, allowing the piston rod to retract normally. Figure 2 As shown, a typical two-position three-way valve consists of a spool valve 200. An externally controlled pilot oil Pi acts on the valve core, causing the spool valve 200 to switch directions, thus connecting port 1 and port 3 or port 2 and port 3 respectively. However, due to structural limitations, the flow capacity of the spool valve 200 is restricted by the valve stem diameter. In high-flow applications, a large valve stem diameter is required, resulting in high processing and manufacturing costs for the valve assembly. Summary of the Invention

[0004] The purpose of this invention is to provide a differential valve assembly to form a differential circuit for hydraulic cylinders in high-flow applications, thereby improving operational efficiency, reducing manufacturing costs, and enhancing versatility.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A differential valve assembly, wherein the differential valve assembly is connected to a hydraulic cylinder to form a differential circuit, the differential valve assembly comprising:

[0007] The valve body is provided with a first working oil port, a second working oil port, a first connecting port, and a second connecting port. Of the first working oil port and the second working oil port, one is for oil inlet and the other is for oil return. The first connecting port is connected to the rodless chamber of the hydraulic cylinder, and the second connecting port is connected to the rod chamber of the hydraulic cylinder. The first working oil port and the first connecting port are connected, and the second working oil port can be connected to the second connecting port.

[0008] A logic valve, wherein the valve body has a first mounting cavity, and the logic valve is detachably mounted in the first mounting cavity, the logic valve includes a spring cavity and a conical cavity, the spring cavity has a control port, and the conical cavity has a first port and a second port, the first port communicating with a first working port, the second port communicating with a second connecting port, and the control port communicating with the second working port; when oil enters through the first working port and oil returns through the second working port, the return oil from the rod cavity of the hydraulic cylinder can pass through the second connecting port and the second working port. Oil enters the conical cavity through the control port, and the return oil from the spring cavity enters the second working port through the control port. This opens the logic valve, allowing the return oil from the rod-side cavity of the hydraulic cylinder to enter the rodless cavity through the logic valve, thus achieving differential operation of the rodless cavity. When oil enters through the second working port and returns through the first working port, the oil enters the spring cavity through the second working port and the control port. The return oil from the conical cavity enters the rodless cavity of the hydraulic cylinder through the first port and the first connecting port, closing the logic valve.

[0009] As an optional embodiment of the differential valve assembly, the differential valve assembly further includes a first check valve and a second check valve. The first check valve is used for unidirectional flow from the first oil port to the first connecting port; the second check valve is used for unidirectional flow from the second working oil port to the second connecting port and the second oil port.

[0010] As an optional embodiment of the differential valve assembly, the valve body is provided with a first control oil circuit, which connects the control oil port and the second working oil port. A throttling check valve assembly is provided on the first control oil circuit. The throttling check valve assembly includes a third check valve and a first throttling element. The third check valve is used for unidirectional flow from the second working oil port to the control oil port. When the logic valve is open, the return oil from the spring chamber returns through the first throttling element and the second working oil port. When the logic valve is closed, the oil enters the spring chamber through the second working oil port and the throttling check valve assembly, closing the logic valve.

[0011] As an alternative to the differential valve assembly, the first throttling element is a first throttling valve, and the first throttling valve and the third check valve are connected in parallel.

[0012] As an optional embodiment of the differential valve assembly, the third check valve includes a check valve seat, a check valve core, and a first spring. A second mounting cavity is provided in the first control oil circuit. The check valve seat is fixed to one end of the second mounting cavity, and the first spring is fixed to the other end of the second mounting cavity. The check valve core is located between the check valve seat and the first spring. The end of the second mounting cavity near the check valve seat is connected to the second working oil port, and the end of the second mounting cavity near the first spring is connected to the control oil port. The oil flowing from the second working oil port to the control oil port drives the check valve core to move relative to the check valve seat to connect the second working oil port and the control oil port.

[0013] As an optional solution for the differential valve assembly, the first throttling element is a first throttling orifice, which is disposed on the one-way valve core and is coaxially disposed with the one-way valve core, so that the oil in the spring cavity can flow to the second working oil port through the first throttling orifice.

[0014] As an alternative to the differential valve assembly, the differential valve assembly further includes a second throttling element, through which the spring cavity and the conical cavity are connected; the flow area of ​​the first throttling element is larger than the flow area of ​​the second throttling element.

[0015] As an alternative to the differential valve assembly, the second throttling element is a second throttling valve. The valve body is also provided with a second control oil circuit, which is used to connect the control oil port and the second oil port. The second throttling valve is located on the second control oil circuit.

[0016] As an optional embodiment of the differential valve assembly, the logic valve includes a logic valve seat, a logic valve core, and a second spring. The logic valve seat is disposed within the first mounting cavity. One end of the second spring is fixed to the valve body, and the other end is connected to the logic valve core. The logic valve seat has a limiting step inside, and the logic valve core has a limiting surface on its outer periphery. The logic valve core slides within the logic valve seat, dividing the interior of the logic valve seat into a spring cavity and a conical cavity. When oil enters the spring cavity, it drives the logic valve core to move towards the conical cavity, causing the limiting surface to abut against the limiting step, thus closing the logic valve. When oil enters the conical cavity, it drives the logic valve core to move towards the spring cavity, causing the limiting surface to disengage from the limiting step, thus opening the logic valve.

[0017] As an alternative to the differential valve assembly, the second throttling element is a second throttling orifice, which is disposed in the logic valve core and is coaxially disposed with the logic valve core so that the spring cavity and the conical cavity are connected.

[0018] As an optional solution for the differential valve assembly, the opening pressure of the logic valve is m, then 1 bar < m < 10 bar.

[0019] As an alternative to the differential valve assembly, if the area ratio of the spring cavity to the conical cavity is n, then 1.5 < n < 2.

[0020] The beneficial effects of this invention are:

[0021] The differential valve assembly provided by this invention includes a valve body and a logic valve. The logic valve includes a spring chamber and a conical chamber. The spring chamber has a control port, and the conical chamber has a first port and a second port. The first port can communicate with a first working port, and the second port can communicate with a second connecting port. The control port is connected to the second working port. When oil enters through the first working port and returns through the second working port, the oil enters the rodless chamber of the hydraulic cylinder through the first working port and the first connecting port. The returning oil from the rod chamber of the hydraulic cylinder enters the conical chamber through the second connecting port and the second port. The returning oil from the spring chamber enters the second working port through the control port. This opens the logic valve, allowing the returning oil from the rod chamber of the hydraulic cylinder to enter the rodless chamber of the hydraulic cylinder through the logic valve, thus realizing the differential of the rodless chamber of the hydraulic cylinder. This allows the piston rod to extend quickly, improving working efficiency. When oil enters through the second working port and returns through the first working port, the oil flows through the second working port and the control port into the spring chamber of the logic valve, closing the logic valve. At this time, the oil can only enter the rod chamber of the hydraulic cylinder through the second connecting port, and the return oil from the rodless chamber of the hydraulic cylinder returns through the first connecting port to the first working port. By detachably mounting the logic valve in the first mounting chamber within the valve body, a logic valve with a flow area matching the applied flow range can be selected, greatly expanding the applicable flow range of the differential valve assembly, improving its versatility, and reducing cost. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the differential circuit of a hydraulic cylinder provided by existing technology;

[0023] Figure 2 This is a schematic diagram of the structure of a spool valve connected to a hydraulic cylinder, provided by existing technology;

[0024] Figure 3 This is a schematic diagram of the differential valve assembly provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the differential valve assembly and hydraulic cylinder connected to form a differential circuit according to an embodiment of the present invention;

[0026] Figure 5 These are five views of the differential valve assembly provided in the embodiments of the present invention;

[0027] Figure 6 yes Figure 5 Sectional view along line AA;

[0028] Figure 7 yes Figure 6 Enlarged view of a section at point I;

[0029] Figure 8 yes Figure 5 Sectional view along the BB direction;

[0030] Figure 9 yes Figure 5 C-axis sectional view;

[0031] Figure 10 yes Figure 9 Enlarged view of section II in the middle.

[0032] In the picture:

[0033] 100. Hydraulic cylinder; 200. Spool valve;

[0034] 1. Valve body; 11. Body; 111. First working port; 112. Second working port; 113. First connecting port; 114. Second connecting port; 115. First mounting cavity; 116. First connecting oil passage; 117. Second connecting oil passage; 118. Third connecting oil passage; 119. Fourth connecting oil passage; 12. Valve cover; 121. First control oil passage; 122. Second control oil passage;

[0035] 2. Logic valve; 21. Logic valve seat; 211. First oil port; 212. Second oil port; 213. Control oil port; 22. Logic valve core; 23. Second spring;

[0036] 3. First check valve;

[0037] 4. Second check valve;

[0038] 5. Throttling check valve assembly; 51. Third check valve; 511. Check valve seat; 512. Check valve core; 5121. First throttling orifice; 513. First spring; 52. First throttling valve;

[0039] 6. Second throttle valve;

[0040] 71. Blockage in the first process; 72. Blockage in the second process;

[0041] 8. Tighten the bolts. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0043] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] like Figures 3-10 As shown, this embodiment provides a differential valve assembly, which is connected to a hydraulic cylinder 100 to form a differential circuit. The differential valve assembly includes a valve body 1, a logic valve 2, a first check valve 3, and a second check valve 4. The valve body 1 has a first working port 111, a second working port 112, a first connecting port 113, and a second connecting port 114. Of the first working port 111 and the second working port 112, one is for oil inlet and the other for oil return. The first connecting port 113 communicates with the rodless chamber of the hydraulic cylinder 100, and the second connecting port 114 communicates with the rod chamber of the hydraulic cylinder 100. A first connecting oil passage 116 is provided inside the valve body 1, and the first working port 111 and the first connecting port 113 are connected through the first connecting oil passage 116. The second working port 112 can communicate with the second connecting port 114.

[0045] The valve body 1 is provided with a first mounting cavity 115, and the logic valve 2 is detachably disposed in the first mounting cavity 115. The logic valve 2 includes a spring cavity and a conical cavity. The spring cavity is provided with a control oil port 213, and the conical cavity is provided with a first oil port 211 and a second oil port 212. The valve body 1 is also provided with a second connecting oil passage 117, a third connecting oil passage 118, a fourth connecting oil passage 119, and a control oil passage. The first oil port 211 can be connected to the first working oil port 111 through the second connecting oil passage 117. The second oil port 212 is connected to the second connecting port 114 through the third connecting oil passage 118. The fourth connecting oil passage 119 is used to connect the second working oil port 112 and the third connecting oil passage 118. The control oil port 213 is connected to the second working oil port 112 through the control oil passage. The logic valve 2 is detachably installed in the first mounting cavity 115. The logic valve 2 with a flow area that matches the applied flow range can be selected according to the applied flow range, which greatly expands the applicable flow range of the differential valve assembly, improves its versatility, and reduces costs.

[0046] Specifically, the logic valve 2 includes a logic valve seat 21, a logic valve core 22, and a second spring 23. The logic valve seat 21 is located in the first mounting cavity 115. One end of the second spring 23 is fixed to the valve body 1, and the other end is connected to the logic valve core 22. The logic valve seat 21 has a limiting step, and the logic valve core 22 has a limiting surface on its outer periphery. The logic valve core 22 slides in the logic valve seat 21. The limiting surface is a conical surface, which divides the logic valve seat 21 into a spring cavity and a conical cavity. When the oil entering the spring cavity drives the logic valve core 22 to move towards the conical cavity, the limiting surface abuts against the limiting step, and the logic valve 2 closes. When the oil entering the conical cavity drives the logic valve core 22 to move towards the spring cavity, the limiting surface disengages from the limiting step, and the logic valve 2 opens.

[0047] Furthermore, if the opening pressure of logic valve 2 is m, then 1 bar < m < 10 bar. For example, the opening pressure of logic valve 2 can be 6 bar, 7 bar, or 8 bar, etc., and those skilled in the art can adjust it according to different application scenarios with different flow ranges. The elastic coefficient of the second spring 23 determines the opening pressure of logic valve 2. The second spring 23 is selected according to the opening pressure of logic valve 2. The larger the elastic coefficient of the second spring 23, the greater its stiffness. The greater the stiffness of the second spring 23, the better the closing characteristics of logic valve 2. However, if the second spring 23 is too stiff, it will affect the micro-controllability of the hydraulic cylinder 100.

[0048] Furthermore, if the area ratio of the spring cavity to the conical cavity is n, then 1.5 < n < 2. If the area ratio of the spring cavity to the conical cavity is too large, it will affect the opening pressure of logic valve 2, and thus affect the opening time of logic valve 2.

[0049] like Figure 6 and Figure 8 As shown, the valve body 1 further includes a body 11 and a valve cover 12. A first mounting cavity 115 is provided on the body 11, and one side of the first mounting cavity 115 is set as an opening to facilitate the assembly and disassembly of the logic valve 2. The valve cover 12 is fixed above the opening by fastening bolts 8. A sealing ring is provided between the outer periphery of the logic valve seat 21 and the inner wall of the first mounting cavity 115 to ensure the sealing between the logic valve 2 and the valve body 1. The logic valve core 22 has a spring mounting hole at one end near the opening. One end of the second spring 23 is fixed in the spring mounting hole, and the other end abuts against the valve cover 12. The control oil port 213 is provided on the valve cover 12 and communicates with the spring cavity. The control oil circuit connects the valve cover 12 and the body 11. The first oil port 211 and the second oil port 212 are both provided on the logic valve seat 21 and both communicate with the conical cavity. The first connecting oil circuit 116, the second connecting oil circuit 117, the third connecting oil circuit 118 and the third connecting oil circuit 118 are all provided inside the body 11. The first working oil port 111, the second working oil port 112, the first connecting port 113, and the second connecting port 114 are all located on the body 11 and are external interfaces of the valve body 1.

[0050] The first check valve 3 is located in the second connecting oil passage 117 and is used for one-way flow from the first oil port 211 to the first connecting port 113. The second check valve 4 is located in the fourth connecting oil passage 119 and is used for one-way flow from the second working oil port 112 to the second connecting port 114 and the second oil port 212. When oil enters through the first working oil port 111 and returns through the second working oil port 112, the first check valve 3 restricts the flow direction of the oil, allowing the oil entering from the first working oil port 111 to enter the rodless chamber of the hydraulic cylinder 100 through the first connecting port 113. The second check valve 4 restricts the flow direction of the oil, allowing the return oil from the rod chamber of the hydraulic cylinder 100 to enter the rodless chamber of the hydraulic cylinder 100, forming a differential circuit. When oil enters through the second working port 112, the oil enters the rod chamber of the hydraulic cylinder 100 through the second check valve 4 and the second connecting port 114. The first check valve 3 restricts the flow direction of the return oil in the rodless chamber of the hydraulic cylinder 100, so that the return oil from the first connecting port 113 flows to the first working port 111. It can also ensure that the rodless chamber of the hydraulic cylinder 100 does not leak when it is subjected to gravity, thus playing a holding role.

[0051] Specifically, both the first check valve 3 and the second check valve 4 are equipped with a return spring. The lower the opening pressure of the return spring, the better, provided that the check valve can be reset. In some cases, the return spring inside the check valve can be removed.

[0052] The main body 11 is also provided with a third mounting cavity and a fourth mounting cavity. The third mounting cavity is located on the second connecting oil passage 117, and the first one-way valve 3 is installed in the third mounting cavity. The fourth mounting cavity is located on the fourth connecting oil passage 119, and the second one-way valve 4 is installed in the fourth mounting cavity.

[0053] When oil enters through the first working port 111 and returns through the second working port 112, the oil flows through the first connecting oil passage 116 and the first connecting port 113 into the rodless chamber of the hydraulic cylinder 100. The return oil from the rod chamber of the hydraulic cylinder 100 flows through the second connecting port 114, the third connecting oil passage 118, and the second port 212 into the conical chamber. The return oil from the spring chamber flows through the control port 213 and the control oil passage to connect with the second working port 112, opening the logic valve 2. The return oil from the rod chamber of the hydraulic cylinder 100 then flows through the logic valve 2 and the first check valve 3 into the rodless chamber of the hydraulic cylinder 100, achieving differential movement of the rodless chamber of the hydraulic cylinder 100, allowing the piston rod to extend rapidly and improving working efficiency. When oil enters through the second working port 112 and returns through the first working port 111, the oil enters the spring chamber through the second working port 112, the control oil circuit, and the control oil port 213, closing the logic valve 2 so that the oil enters the rod chamber of the hydraulic cylinder 100 through the second check valve 4. The return oil from the rodless chamber of the hydraulic cylinder 100 enters the first working port 111 through the first connecting port 113 and the first connecting oil circuit 116.

[0054] As an optional embodiment of the differential valve assembly, the control oil circuit includes a first control oil circuit 121, which connects to a control port 213 and a second working port 112. A throttling check valve assembly 5 is installed on the first control oil circuit 121. The throttling check valve assembly 5 includes a third check valve 51 and a first throttling element. The third check valve 51 allows unidirectional flow from the second working port 112 to the control port 213. When the logic valve 2 is open, the return oil from the spring chamber flows back through the first throttling element and the second working port 112. When the logic valve 2 is closed, the oil flows through the second working port 112 and the throttling check valve assembly 5 into the spring chamber, closing the logic valve 2. The first control oil circuit 121 controls the opening and closing of the logic valve 2. The first control oil circuit 121 extends from the control port 213 on the valve cover 12 to the body 11, connecting to the second working port 112 on the body 11. The throttling check valve assembly 5 is located inside the valve cover 12.

[0055] like Figure 9 and Figure 10 As shown, specifically, the third check valve 51 includes a check valve seat 511, a check valve core 512, and a first spring 513. A second mounting cavity is provided in the first control oil circuit 121, and the second mounting cavity is located inside the valve cover 12. The check valve seat 511 is fixed to one end of the second mounting cavity, and the first spring 513 is fixed to the other end of the second mounting cavity. The check valve core 512 is located between the check valve seat 511 and the first spring 513. The end of the second mounting cavity near the check valve seat 511 is connected to the second working oil port 112, and the end of the second mounting cavity near the first spring 513 is connected to the control oil port 213. The oil flowing from the second working oil port 112 to the control oil port 213 drives the check valve core 512 to move relative to the check valve seat 511 to connect the second working oil port 112 and the control oil port 213. When oil enters through the second working port 112, the oil flows through the third check valve 51 and the control port 213 into the spring chamber, driving the logic valve core 22 to move closer to the conical cavity until the limiting surface abuts against the limiting step, thereby closing the logic valve 2. This allows the oil to enter the rod chamber of the hydraulic cylinder 100 through the second connecting port 114. When oil enters through the first working port 111, the return oil from the rod chamber of the hydraulic cylinder 100 enters the third connecting oil passage 118 through the second connecting port 114, and then enters the conical cavity through the second port 212. This drives the logic valve core 22 to move closer to the spring chamber until the limiting surface disengages from the limiting step. The return oil from the spring chamber can only return to the second working port 112 through the first throttling element, causing the logic valve 2 to open slowly, reducing the impact caused by the differential flow.

[0056] In this embodiment, in order to facilitate the processing of the first control oil circuit 121 and the installation of the third check valve 51, the first control oil circuit 121 is connected to one side of the valve cover 12. After the third check valve 51 is installed, in order to block the first control oil circuit 121, a first process plug 71 is also provided at the end of the check valve seat 511 away from the first spring 513, and the control oil circuit is blocked by the first process plug 71.

[0057] The opening pressure of the first spring 513 should be as small as possible while still satisfying the reset of the one-way valve core 512.

[0058] In an optional embodiment of the present invention, such as Figure 3 In the schematic diagram of the differential valve assembly shown, the first throttling element is the first throttling valve 52, which is connected in parallel with the third check valve 51. With the first throttling valve 52 and the third check valve 51 connected in parallel, when the control logic valve 2 is closed, the oil from the second working port 112 enters the spring chamber via the third check valve 51. When the control logic valve 2 is open, the return oil from the spring chamber enters the second working port 112 via the first throttling valve 52.

[0059] In another optional embodiment of the invention, such as Figure 10 As shown, the first throttling element is a first throttling orifice 5121, which is disposed on the one-way valve core 512 and coaxially arranged with the one-way valve core 512, so that the oil in the spring cavity can flow to the second working oil port 112 through the first throttling orifice 5121. In this embodiment, by providing the first throttling orifice 5121 at the center of the one-way valve core 512 of the third one-way valve 51, when the third one-way valve 51 is closed, the return oil from the spring cavity can also flow to the second working oil port 112 through the first throttling orifice 5121 at the center of the one-way valve core 512.

[0060] In the existing technology, the spool of the spool valve connected to the hydraulic cylinder 100 to form a differential circuit needs to reciprocate within the spool valve body. A clearance exists between the spool valve core and the spool valve body to prevent jamming. However, this clearance results in some oil leakage, which cannot meet the settling requirements of some hydraulic cylinders 100. Especially when the load on the hydraulic cylinder 100 is heavy, the settling amount increases significantly, affecting the holding position of the hydraulic cylinder 100.

[0061] To reduce leakage in the differential valve assembly, a second throttling element is also included. The spring chamber and the conical chamber are connected through the second throttling element. When oil enters through the second working port 112, the oil enters the spring chamber through the first control oil circuit 121, and the oil in the conical chamber enters the spring chamber through the second throttling element. Under the action of the second spring 23, the limiting surface of the logic valve core 22 tightly abuts against the limiting step of the logic valve seat 21. In addition, when the rod chamber of the hydraulic cylinder 100 is subjected to gravity, the spring chamber and the conical chamber are connected. Under the action of the second spring 23, the logic valve core 22 is pressed tightly against the logic valve seat 21, preventing the pressure oil in the conical chamber from leaking and thus maintaining its position.

[0062] Furthermore, the flow area of ​​the first throttling element is greater than that of the second throttling element. Setting the flow area of ​​the second throttling element to be smaller than that of the first throttling element ensures that the return oil from the spring cavity is greater than the inlet oil from the conical cavity. This guarantees that when oil enters through the first working port 111, the return oil from the rod-side cavity of the hydraulic cylinder 100 can smoothly open the logic valve 2 and enter the rodless cavity of the hydraulic cylinder 100, thus achieving differential operation of the rodless cavity of the hydraulic cylinder 100.

[0063] In an optional embodiment of the present invention, such as Figure 3 and Figure 6 As shown, the second throttling element is a second throttling valve 6. The control oil circuit also includes a second control oil circuit 122, which connects the control oil port 213 and the second oil port 212. The second throttling valve 6 is installed on the second control oil circuit 122. With the second throttling element set as the second throttling valve 6, when oil enters through the second working oil port 112, the return oil from the conical cavity enters the spring cavity through the second control oil circuit 122, thereby causing the logic valve core 22 to press against the logic valve seat 21 to prevent leakage.

[0064] To facilitate the machining of the second control oil circuit 122 and the installation of the second throttle valve 6, one end of the second control oil circuit 122 is connected to the valve cover 12. After the second throttle valve 6 is installed, the second control oil circuit 122 is blocked by the second process plug 72.

[0065] In another optional embodiment of the present invention, the second throttling element is a second throttling orifice, which is disposed in the logic valve core 22 and coaxially disposed with the logic valve core 22, so that the control port 213 and the second port 212 are connected. By setting the second throttling orifice in the center of the logic valve core 22, the connection between the spring cavity and the conical cavity is realized, which also serves to prevent leakage.

[0066] In the differential valve assembly provided in this embodiment, when high-pressure oil enters through the first working port 111, due to the presence of the first check valve 3, the oil can only enter the rodless chamber of the hydraulic cylinder 100 through the first connecting port 113. The return oil from the rod chamber of the hydraulic cylinder 100, after passing through the second connecting port 114, cannot directly return through the second working port 112 due to the presence of the second check valve 4. Instead, it can only enter the conical chamber of the logic valve 2 through the second port 212 via the third connecting oil path 118. Part of the return oil from the spring chamber returns through the first control oil path 121 and the second working port 112, while the other part returns through the second control oil path 122 and the second connecting port 114. Because the flow area of ​​the second throttle valve 6 is smaller than that of the first throttle valve 52, the oil in the spring chamber returns through the second working port 112, the spring chamber is depressurized, and the logic valve 2 opens. The return oil from the rod chamber of the hydraulic cylinder 100 enters the first connection port 113 through the second connection port 114, the third connection oil passage 118, the logic valve 2, the first check valve 3, and the first connection oil passage 116, so as to enter the rodless chamber of the hydraulic cylinder 100, thereby realizing the differential of the rodless chamber of the hydraulic cylinder 100.

[0067] When high-pressure oil enters through the second working port 112, the oil passes through the second check valve 4 of the fourth connecting oil passage 119 to the third connecting oil passage 118. At this time, part of the oil passes through the second connecting port 114, and the other part enters the spring chamber through the second control oil passage 122. Simultaneously, the high-pressure oil from the second working port 112 enters the spring chamber through the first control oil passage 121 and the throttling check valve assembly 5. The oil from the first control oil passage 121 and the second control oil passage 122 simultaneously acts on the spring chamber. Under the action of the second spring 23, the logic valve core 22 is pressed tightly against the logic valve seat 21, the logic valve 2 is closed, and the oil from the second connecting port 114 can only enter the rod chamber of the hydraulic cylinder 100. The return oil from the rodless chamber of the hydraulic cylinder 100 returns through the first connecting port 113 and the first working port 111.

[0068] The differential valve assembly provided in this embodiment achieves differential control through the switching of logic valve 2. The flow range adaptable to logic valve 2 is greatly expanded, and it can adapt to a flow range from 200L / min to 800L / min by replacing logic valve 2 with different flow areas. Moreover, the logic valve core 22 has good sealing performance, which can meet the requirements of strict leakage control of hydraulic cylinder 100.

[0069] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A differential valve assembly, wherein the differential valve assembly is connected to a hydraulic cylinder (100) to form a differential circuit, characterized in that, include: The valve body (1) is provided with a first working port (111), a second working port (112), a first connecting port (113), and a second connecting port (114). Of the first working port (111) and the second working port (112), one is for oil inlet and the other is for oil return. The first connecting port (113) is connected to the rodless chamber of the hydraulic cylinder (100), and the second connecting port (114) is connected to the rod chamber of the hydraulic cylinder (100). The first working port (111) and the first connecting port (113) are connected, and the second working port (112) can be connected to the second connecting port (114). A logic valve (2) is provided on the valve body (1) with a first mounting cavity (115). The logic valve (2) is detachably disposed in the first mounting cavity (115). The logic valve (2) includes a spring cavity and a conical cavity. The spring cavity is provided with a control port (213). The conical cavity is provided with a first port (211) and a second port (212). The first port (211) can communicate with the first working port (111). The second port (212) is communicated with the second connecting port (114). The control port (213) is communicated with the second working port (112). When oil enters the first working port (111) and oil returns from the second working port (112), the return oil from the rod cavity of the hydraulic cylinder (100) can pass through the second connecting port (114). The oil enters the conical cavity through the second oil port (212) and the return oil from the spring cavity enters the second working oil port (112) through the control oil port (213), opening the logic valve (2) so that the return oil from the rod cavity of the hydraulic cylinder (100) enters the rodless cavity of the hydraulic cylinder (100) through the logic valve (2), realizing the differential of the rodless cavity of the hydraulic cylinder (100); when the second working oil port (112) is filled with oil and the first working oil port (111) is filled with oil, the oil enters the spring cavity through the second working oil port (112) and the control oil port (213), and the return oil from the conical cavity enters the rodless cavity of the hydraulic cylinder (100) through the first oil port (211) and the first connecting port (113), closing the logic valve (2); The differential valve assembly further includes a first check valve (3) and a second check valve (4). The first check valve (3) is used for one-way flow from the first port (211) to the first connecting port (113). The second check valve (4) is used for one-way flow from the second working port (112) to the second connecting port (114) and the second port (212).

2. The differential valve assembly according to claim 1, characterized in that, The valve body (1) is provided with a first control oil circuit (121), which is used to connect the control oil port (213) and the second working oil port (112). The first control oil circuit (121) is provided with a throttling check valve assembly (5), which includes a third check valve (51) and a first throttling element. The third check valve (51) is used for one-way flow from the second working oil port (112) to the control oil port (213). When the logic valve (2) is open, the return oil of the spring cavity returns through the first throttling element and the second working oil port (112). When the logic valve (2) is closed, the oil enters the spring cavity through the second working oil port (112) and the throttling check valve assembly (5), thus closing the logic valve (2).

3. The differential valve assembly according to claim 2, characterized in that, The first throttling element is a first throttling valve (52), and the first throttling valve (52) and the third one-way valve (51) are connected in parallel.

4. The differential valve assembly according to claim 2, characterized in that, The third one-way valve (51) includes a one-way valve seat (511), a one-way valve core (512), and a first spring (513). A second mounting cavity is provided in the first control oil circuit (121). The one-way valve seat (511) is fixed to one end of the second mounting cavity, and the first spring (513) is fixed to the other end of the second mounting cavity. The one-way valve core (512) is located between the one-way valve seat (511) and the first spring (513). The end of the second mounting cavity near the one-way valve seat (511) is connected to the second working oil port (112), and the end of the second mounting cavity near the first spring (513) is connected to the control oil port (213). The oil flowing from the second working oil port (112) to the control oil port (213) drives the one-way valve core (512) to move relative to the one-way valve seat (511) to connect the second working oil port (112) and the control oil port (213).

5. The differential valve assembly according to claim 4, characterized in that, The first throttling element is a first throttling orifice (5121), which is disposed on the one-way valve core (512). The first throttling orifice (5121) and the one-way valve core (512) are coaxially disposed so that the oil in the spring cavity can flow to the second working oil port (112) through the first throttling orifice (5121).

6. The differential valve assembly according to claim 2, characterized in that, The differential valve assembly further includes a second throttling element, through which the spring cavity and the conical cavity are connected; the flow area of ​​the first throttling element is greater than that of the second throttling element.

7. The differential valve assembly according to claim 6, characterized in that, The second throttling element is a second throttling valve (6). The valve body (1) is also provided with a second control oil circuit (122). The second control oil circuit (122) is used to connect the control oil port (213) and the second oil port (212). The second throttling valve (6) is provided on the second control oil circuit (122).

8. The differential valve assembly according to claim 6, characterized in that, The logic valve (2) includes a logic valve seat (21), a logic valve core (22), and a second spring (23). The logic valve seat (21) is located in the first mounting cavity (115). One end of the second spring (23) is fixed to the valve body (1), and the other end is connected to the logic valve core (22). The logic valve seat (21) has a limiting step inside, and the logic valve core (22) has a limiting surface on its outer periphery. The logic valve core (22) slides in the logic valve seat (21), dividing the logic valve seat (21) into a spring cavity and a conical cavity. When the oil entering the spring cavity drives the logic valve core (22) to move closer to the conical cavity, the limiting surface abuts against the limiting step, and the logic valve (2) closes. When the oil entering the conical cavity drives the logic valve core (22) to move closer to the spring cavity, the limiting surface disengages from the limiting step, and the logic valve (2) opens.

9. The differential valve assembly according to claim 8, characterized in that, The second throttling element is a second throttling orifice, which is disposed on the logic valve core (22), and the second throttling orifice and the logic valve core (22) are coaxially disposed so that the spring cavity and the conical cavity are connected.

10. The differential valve assembly according to claim 1, characterized in that, The opening pressure of the logic valve (2) is m, then 1 bar < m < 10 bar.

11. The differential valve assembly according to claim 1, characterized in that, If the area ratio of the spring cavity to the conical cavity is n, then 1.5 < n < 2.

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