Valve assembly and hydraulic cylinder

Abstract

The utility model relates to the technical field of fluid pressure executing mechanisms, and provides a valve assembly and a hydraulic cylinder. The valve assembly comprises a pressure expansion type one-way valve; the ratio of the cross sectional area of the matching part of the push rod of the valve assembly and the power source to the cross sectional area of the valve hole of the one-way valve is greater than 3 and less than 12; as the hydraulic control ratio of the one-way valve is the ratio of the cross sectional area of the matching part on the push rod to the cross sectional area of the valve hole of the one-way valve, under the condition that the installation space of the one-way valve in the hydraulic cylinder is fixed, the pressure expansion type one-way valve is used for replacing the existing insertion type one-way valve; the cross sectional area of the valve hole of the pressure-expansion type one-way valve is smaller than that of the valve hole of the plug-in type one-way valve, the hydraulic control ratio of the pressure-expansion type one-way valve can be larger than that of the plug-in type one-way valve, the pressure needed for opening the hydraulic cylinder is reduced by selecting the pressure-expansion type one-way valve, and then the sensitivity of the hydraulic cylinder is improved.

Description

Technical Field

[0001] This utility model relates to the field of fluid pressure actuator technology, specifically to a valve assembly and a hydraulic cylinder. Background Technology

[0002] Typically, the effective working volumes of the two chambers of a hydraulic cylinder (generally referred to as the rod chamber and the rodless chamber) differ significantly. To prevent the piston and piston rod from sliding down, i.e., to ensure rapid oil discharge while preventing reverse flow of hydraulic oil under the pressure of the hydraulic system, a check valve is installed in the valve assembly of the hydraulic cylinder. Since the hydraulic control ratio of the check valve affects the sensitivity of the hydraulic cylinder system, and the hydraulic control ratio is essentially the ratio of the area affected by the load pressure to the area affected by the control chamber pressure, and when the load pressure acts as an aid to opening the check valve, the opening pressure of the check valve equals the resistance of the check valve minus the load pressure, the larger the hydraulic control ratio of the check valve, the smaller the opening pressure of the valve assembly. Conversely, the smaller the hydraulic control ratio, the smaller the opening pressure of the valve assembly.

[0003] Existing check valves mounted on hydraulic cylinders are typically insert-type check valves. When the installation space for the check valve within the hydraulic cylinder is limited, only small-volume check valves can be selected. However, small-volume check valves, limited by their own size, can only be designed with a hydraulic control ratio of no more than 3:1, which cannot meet the sensitivity requirements of the hydraulic cylinder. Summary of the Invention

[0004] The purpose of this invention is to develop a valve assembly and a hydraulic cylinder that can improve the sensitivity of the hydraulic cylinder by increasing the hydraulic control ratio of the check valve when the installation space of the check valve in the hydraulic cylinder is limited.

[0005] This utility model is achieved through the following technical solution:

[0006] In a first aspect, a valve assembly is provided, comprising a valve body, a push rod, a return spring, and two plugs. The valve body has a first valve cavity and a second valve cavity, and the two plugs respectively block the openings of the first valve cavity and the second valve cavity located at opposite ends of the valve body. The second valve cavity includes a first mounting cavity connected to the first valve cavity and a second mounting cavity connected to the end of the first mounting cavity away from the first valve cavity. The push rod includes an insertion portion that clearance-fits with the inner wall of the first mounting cavity and a mating portion that slides and seals with the inner wall of the second mounting cavity. The return spring is sleeved on the insertion portion of the push rod and confined between the first mounting cavity and the mating portion. The assembly further includes:

[0007] A one-way valve is assembled between the first valve chamber and the first mounting chamber; the one-way valve is a pressure-expanding one-way valve, and the ratio of the cross-sectional area of ​​the mating part of the push rod to the cross-sectional area of ​​the valve hole of the one-way valve is greater than 3 and less than 12.

[0008] The cross-sectional area of ​​the valve orifice of the aforementioned check valve specifically refers to the cross-sectional area of ​​the valve orifice through which the check valve uses a valve ball to control the flow of fluid.

[0009] The beneficial effects of the above technical solution are as follows: the hydraulic control ratio of the check valve is the ratio of the cross-sectional area of ​​the mating part on the push rod to the cross-sectional area of ​​the valve hole of the check valve; in small-sized and compact hydraulic cylinders (specifically, the installation space of the check valve inside the hydraulic cylinder is small), replacing the existing insertion check valve with a pressure-expanding check valve can effectively improve the hydraulic control ratio, thereby improving the sensitivity of the hydraulic cylinder; the specific principle of its effect is as follows: under the condition that the installation space of the check valve inside the hydraulic cylinder remains unchanged, since the cross-sectional area of ​​the valve hole of the pressure-expanding check valve is smaller than that of the insertion check valve, the hydraulic control ratio of the pressure-expanding check valve is greater than that of the insertion check valve. Selecting a pressure-expanding check valve is equivalent to reducing the pressure required for the hydraulic cylinder to open, thus improving the sensitivity of the hydraulic cylinder.

[0010] In one possible implementation, the diameter of the first mounting cavity is smaller than the diameter of the second mounting cavity, and a stepped portion is formed between the first mounting cavity and the second mounting cavity; the diameter of the insertion portion of the push rod is smaller than the diameter of its mating portion, and a stepped surface is formed between the insertion portion and the mating portion, and the stepped portion and the stepped surface are mutually restrictive to limit the movement stroke of the push rod in the second valve cavity.

[0011] Secondly, a hydraulic cylinder is also provided, including an inner cavity, a piston assembly assembled in the inner cavity, and a valve assembly as described above, wherein the inner cavity of the hydraulic cylinder is connected to an oil tank through the valve assembly.

[0012] In one possible implementation, the piston assembly includes a piston and a piston rod, with the piston connected to one end of the piston rod. A guide sleeve is provided at the opening of the hydraulic cylinder into which the piston rod extends, guiding the piston rod and sealing the inner cavity of the hydraulic cylinder. The piston divides the inner cavity of the hydraulic cylinder into a rod chamber for piston rod extension and retraction, and a rodless chamber located on the side of the piston away from the piston rod. A third mounting cavity is provided between the second mounting cavity and the plug, with the bottom of the mating portion of the push rod exposed within the third mounting cavity. The rod chamber of the hydraulic cylinder is connected to the first valve chamber of the valve assembly via a fluid passage, and the rodless chamber of the hydraulic cylinder is connected to the third mounting cavity of the valve assembly via a rodless chamber channel.

[0013] In one possible implementation, the valve body is provided with a first inlet / outlet channel and a second inlet / outlet channel to connect to the oil tank; the first inlet / outlet channel connects to the third mounting cavity of the valve assembly, and the second inlet / outlet channel connects to the first mounting cavity of the valve assembly.

[0014] In one possible implementation, the check valve is a check valve that allows fluid to flow only from the first mounting chamber to the first valve chamber.

[0015] In one possible implementation, the center lines of the first valve chamber, the first mounting chamber, the second mounting chamber, and the third mounting chamber coincide.

[0016] In one possible implementation, a spherical bearing is provided on one side of the hydraulic cylinder to support the cylinder body and ensure the stability of the hydraulic cylinder operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the valve assembly in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the hydraulic cylinder in an embodiment of the present invention;

[0019] Figure 3 for Figure 2 Sectional view at point BB;

[0020] Figure 4 for Figure 2 Sectional view at point AA;

[0021] Figure 5 for Figure 2 A cross-sectional view of the hydraulic cylinder.

[0022] In the diagram, 1 is the valve assembly; 10 is the valve body; 100 is the valve chamber; 1000 is the first valve chamber; 1001 is the second valve chamber; 1001a is the first mounting chamber; 1001b is the second mounting chamber; 1001c is the third mounting chamber; 101 is the first inlet / outlet liquid channel; 102 is the second inlet / outlet liquid channel; 11 is the check valve; 12 is the push rod; 120 is the mating part; 121 is the insertion part; 13 is the return spring; 14 is the plug; 2 is the hydraulic cylinder; 200 is the rod chamber; 201 is the rodless chamber; 2011 is the rodless chamber channel; 210 is the piston; 211 is the piston rod; 22 is the guide sleeve; 23 is the spherical bearing; and 24 is the liquid passage. Detailed Implementation

[0023] First, those skilled in the art should understand that the following embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] To make the objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments are described in detail below with reference to the accompanying drawings.

[0027] like Figure 1 As shown, this embodiment provides a valve assembly 1 with a large hydraulic control ratio (compared to existing valve assemblies), which can be assembled onto various models of hydraulic cylinders to ensure uniform force distribution and smooth operation of the hydraulic cylinder. The valve assembly 1 includes a valve body 10, a push rod 12, a return spring 13, and two plugs 14. The valve body 10 has a valve cavity 100, which is divided into a first valve cavity 1000 and a second valve cavity 1001. The two plugs 14 respectively seal the openings of the first valve cavity 1000 and the second valve cavity 1001 located at both ends of the valve body 10, thereby enclosing a sealed space within the valve body 10 to facilitate the flow of hydraulic oil within the valve assembly 1.

[0028] Specifically, the second valve chamber 1001 includes a first mounting chamber 1001a and a second mounting chamber 1001b with successively increasing diameters and connected to each other, and a third mounting chamber 1001c located at the opening of the second valve chamber 1001; the center lines of the first valve chamber 1001, the first mounting chamber 1001a, the second mounting chamber 1001b, and the third mounting chamber 1001c coincide.

[0029] In this embodiment, a one-way valve 11 is provided between the first valve chamber 1000 and the first mounting chamber 1001a to control the flow of liquid from the first mounting chamber 1001a to the first valve chamber 1000; the one-way valve 11 is a pressure-expanding one-way valve (for example, the pressure-expanding one-way valve can be a pressure-expanding one-way valve of the Kongrui brand, with the product name BR660080024100). The cross-sectional area of ​​the valve orifice of the pressure-expanding one-way valve 11 is smaller (compared to existing insert-type one-way valves or cartridge-type one-way valves), and it can be assembled into the valve chamber 1000, which has a smaller space.

[0030] A stepped portion is formed between the first mounting cavity 1001a and the second mounting cavity 1001b; the push rod 12 includes a smaller diameter insertion portion 121 and a larger diameter mating portion 120, and a stepped surface is formed between the insertion portion 121 and the mating portion 120; the insertion portion 121 of the push rod 12 is inserted into the first mounting cavity 1001a and has a clearance fit with the inner wall of the first mounting cavity 1001a, and the insertion portion 121 of the push rod 12 is used to push the one-way valve 11 to control the first The oil passage between the mounting cavity 1001a and the first valve cavity 1000 is open or closed; the stepped surface of the push rod 12 is matched with the stepped limiting fit of the second mounting cavity 1001b, the second mounting cavity 1001b limits the movement stroke of the push rod 12, and the mating part 120 of the push rod 12 is slidably sealed with the inner peripheral wall of the second mounting cavity 1001b. When the stepped surface of the push rod 12 abuts against the stepped part of the second mounting cavity 1001b, the insertion part 121 of the push rod 12 pushes upward and opens the one-way valve 11.

[0031] Reference Figure 2-5 This utility model also provides an embodiment of a hydraulic cylinder, wherein the hydraulic cylinder 2 is connected to an oil tank through the valve assembly 1 in the above embodiment; the hydraulic cylinder 2 is provided with a piston 210, the piston 210 is connected to one end of a piston rod 211, a guide sleeve 22 is provided at the opening of the hydraulic cylinder 2 into which the piston rod 211 extends, and the guide sleeve 22 seals the inner cavity of the hydraulic cylinder 2; the piston 210 divides the inner cavity of the hydraulic cylinder 2 into a rod chamber 200 for the extension and retraction of the piston rod 211, and a rodless chamber 201 that does not accommodate the piston rod 211.

[0032] In this embodiment, the rod chamber 200 of the hydraulic cylinder 2 is connected to the first valve chamber 1000 of the valve assembly 1 through the fluid passage 24, and the rodless chamber 201 of the hydraulic cylinder 2 is connected to the third mounting chamber 1001c of the valve assembly 1 through the rodless chamber passage 2011; the one-way valve 11 controls the oil circuit between the first valve chamber 1000 and the first mounting chamber 1001a.

[0033] The valve assembly 1 is connected to the oil tank through a first inlet / outlet channel 101 and a second inlet / outlet channel 102. Specifically, the first inlet / outlet channel 101 connects to the third mounting cavity 1001c of the valve assembly 1, and the third mounting cavity 1001c connects to the rodless cavity 201 of the hydraulic cylinder 2 through a rodless cavity channel 2011. The second inlet / outlet channel 102 connects to the first mounting cavity 1001a of the valve assembly 1. A one-way valve 11 controls the opening and closing of the first mounting cavity 1001a and the first valve cavity 1000. The first valve cavity 1000 connects to the rod cavity 200 of the hydraulic cylinder 2 through a fluid passage 24.

[0034] A spherical bearing 23 is provided on one side of the hydraulic cylinder 2 to support the cylinder body of the hydraulic cylinder and ensure the stability of the operation of the hydraulic cylinder 2.

[0035] During the hydraulic cylinder retraction cycle:

[0036] The oil in the tank is pumped into the second inlet / outlet channel 102 and flows into the first mounting cavity 1001a. The hydraulic pressure of the oil pushes open the check valve 11, and the oil enters the first valve cavity 1000. From the first valve cavity 1000, it flows through the liquid passage 24 into the rod cavity 200, pushing against the piston 210 and causing the piston rod 211 to retract. Figure 5 (In the middle, piston rod 211 and piston 210 move to the right).

[0037] At the same time, the oil in the rodless chamber 201 enters the third mounting chamber 1001c through the rodless chamber channel 2011, and then flows into the oil tank through the first inlet and outlet channel 101.

[0038] When the oil pump stops supplying oil to the second inlet / outlet channel 102, the check valve 11 closes, blocking the oil passage between the first mounting chamber 1001a and the first valve chamber 1000, and preventing the oil in the rod chamber 200 from flowing back.

[0039] During the cylinder extension cycle:

[0040] The oil in the tank is pumped into the first inlet / outlet channel 101 and flows into the third mounting cavity 1001c. The oil applies pressure to the mating part 120 of the push rod 12. The second mounting cavity 1001b restricts the movement stroke of the push rod 12 and hydraulically pushes the push rod 12 upward until the insertion part 121 of the push rod 12 pushes the one-way valve 11 upward, opening the oil passage between the first mounting cavity 1001a and the first valve cavity 1000. After the one-way valve 11 is opened, the oil in the rod cavity 200 flows back to the tank through the liquid passage 24, the first valve cavity 1000, the first mounting cavity 1001a, and the second inlet / outlet channel 102.

[0041] During this process, the oil in the third mounting cavity 1001c enters the rodless cavity 201 through the rodless cavity channel 2011, pushing the piston 210 and causing the piston rod 211 to extend. Figure 5 (In the middle, piston rod 211 and piston 210 move to the left).

[0042] The pressure that the oil in the third mounting cavity 1001c needs to apply to the mating part 120 of the push rod 12 is determined by the hydraulic control ratio. If the pressure of the one-way valve locked at the valve hole is 24MPa, then the push rod 12 needs to overcome the 24MPa pressure to open the oil circuit. If the hydraulic control ratio is 12:1, then the hydraulic pressure that the mating part 120 of the push rod 12 needs to be subjected to is at least 2MPa in order to open the one-way valve 11.

[0043] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0044] In the description of this application, the reference to terms such as "this embodiment," "an embodiment," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A valve assembly, comprising a valve body (10), a push rod (12), a return spring (13), and two plugs (14), wherein the valve body (10) has a first valve chamber (1000) and a second valve chamber (1001), and the two plugs (14) respectively block the openings of the first valve chamber (1000) and the second valve chamber (1001) located at both ends of the valve body (10); The second valve chamber (1001) includes a first mounting chamber (1001a) connected to the first valve chamber (1000), and a second mounting chamber (1001b) connected to the end of the first mounting chamber (1001a) away from the first valve chamber (1000). The push rod (12) includes an insertion portion (121) that is clearance-fitted with the inner wall of the first mounting cavity (1001a) and a mating portion (120) that is slidingly and sealingly fitted with the inner wall of the second mounting cavity (1001b). The return spring (13) is sleeved on the insertion portion (121) of the push rod (12) and confined between the first mounting cavity (1001a) and the mating portion (120), characterized in that, Also includes: A one-way valve (11) is assembled between the first valve chamber (1000) and the first mounting chamber (1001a); the one-way valve (11) is a pressure-expanding one-way valve; the ratio of the cross-sectional area of ​​the mating part (120) of the push rod (12) to the cross-sectional area of ​​the valve hole of the one-way valve (11) is greater than 3 and less than 12.

2. The valve assembly according to claim 1, characterized in that, The diameter of the first mounting cavity (1001a) is smaller than the diameter of the second mounting cavity (1001b), and a stepped portion is formed between the first mounting cavity (1001a) and the second mounting cavity (1001b); the diameter of the insertion portion (121) of the push rod (12) is smaller than the diameter of its mating portion (120), and a stepped surface is formed between the insertion portion (121) and the mating portion (120), and the stepped portion and the stepped surface are mutually restrictive to limit the movement stroke of the push rod (12) in the second valve cavity (1001).

3. A hydraulic cylinder, characterized in that, The hydraulic cylinder includes an inner cavity, a piston assembly assembled in the inner cavity, and a valve assembly (1) as claimed in claim 1 or 2, wherein the inner cavity of the hydraulic cylinder is connected to an oil tank via the valve assembly (1).

4. The hydraulic cylinder according to claim 3, characterized in that, The piston assembly includes a piston (210) and a piston rod (211). The piston (210) is connected to one end of the piston rod (211). The hydraulic cylinder (2) has a guide sleeve (22) at the opening into which the piston rod (211) extends to guide the piston rod (211), and the guide sleeve (22) seals the inner cavity of the hydraulic cylinder (2). The piston (210) divides the inner cavity of the hydraulic cylinder (2) into a rod chamber (200) for the extension and retraction of the piston rod (211) and a rodless chamber (201) located on the side of the piston (210) away from the piston rod (211). A third mounting cavity (1001c) is provided between the second mounting cavity (1001b) and the plug (14), and the bottom of the mating part (120) of the push rod (12) is exposed in the third mounting cavity (1001c); The rod chamber (200) of the hydraulic cylinder (2) is connected to the first valve chamber (1000) of the valve assembly (1) through a fluid passage (24), and the rodless chamber (201) of the hydraulic cylinder (2) is connected to the third mounting chamber (1001c) of the valve assembly (1) through a rodless chamber passage (2011).

5. The hydraulic cylinder according to claim 4, characterized in that, The valve body (10) is provided with a first inlet / outlet channel (101) and a second inlet / outlet channel (102) to connect to the oil tank; the first inlet / outlet channel (101) connects to the third mounting cavity (1001c) of the valve assembly (1), and the second inlet / outlet channel (102) connects to the first mounting cavity (1001a) of the valve assembly (1).

6. The hydraulic cylinder according to claim 3, characterized in that, The one-way valve (11) is a one-way valve that allows fluid to flow only from the first mounting chamber (1001a) to the first valve chamber (1000).

7. The hydraulic cylinder according to claim 3, characterized in that, The center lines of the first mounting cavity (1001a), the second mounting cavity (1001b), and the third mounting cavity (1001c) coincide.

8. The hydraulic cylinder according to claim 3, characterized in that, The hydraulic cylinder (2) is provided with a spherical bearing (23) on one side.

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