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CN-224228978-U - Valve assembly and hydraulic cylinder

CN224228978UCN 224228978 UCN224228978 UCN 224228978UCN-224228978-U

Abstract

The utility model relates to the technical field of fluid pressure actuating mechanisms, and provides a valve assembly and a hydraulic cylinder, wherein the valve assembly comprises a pressure expansion type one-way valve, the ratio of the cross section area of a matched part of a push rod of the valve assembly and the cross section area of a valve hole of the one-way valve to the cross section area of the valve hole of the one-way valve is more than 3 and less than 12, and the hydraulic control ratio of the one-way valve is the ratio of the cross section area of the matched part of the push rod to the cross section area of the valve hole of the one-way valve.

Inventors

  • JIANG CHENGSHU
  • SHU PINGGUO
  • MAO YUPING

Assignees

  • 宁波中天联合机电制造有限公司

Dates

Publication Date
20260512
Application Date
20250519

Claims (8)

  1. 1. A valve assembly comprises a valve body (10), a push rod (12) and a return spring (13), and two plugs (14), wherein the valve body (10) is provided with a first valve cavity (1000) and a second valve cavity (1001), and the two plugs (14) are used for respectively plugging openings of the first valve cavity (1000) and the second valve cavity (1001) which are positioned on two end parts of the valve body (10); The second valve cavity (1001) comprises a first installation cavity (1001 a) connected with the first valve cavity (1000), and a second installation cavity (1001 b) connected with one end of the first installation cavity (1001 a) far away from the first valve cavity (1000); The push rod (12) comprises an insertion part (121) in clearance fit with the inner side wall of the first mounting cavity (1001 a), and a fit part (120) in sliding seal fit with the inner side wall of the second mounting cavity (1001 b); the return spring (13) is sleeved on the insertion part (121) of the push rod (12) and is limited between the first mounting cavity (1001 a) and the matching part (120), and is characterized by further comprising: The one-way valve (11) is assembled between the first valve cavity (1000) and the first mounting cavity (1001 a), the one-way valve (11) is a compression-expansion one-way valve, and the ratio of the cross section area of the matching part (120) of the push rod (12) to the cross section area of the valve hole of the one-way valve (11) is more than 3 and less than 12.
  2. 2. The valve assembly of claim 1, wherein the diameter of the first mounting cavity (1001 a) is smaller than the diameter of the second mounting cavity (1001 b), a step is formed between the first mounting cavity (1001 a) and the second mounting cavity (1001 b), the diameter of the insertion portion (121) of the pushrod (12) is smaller than the diameter of the mating portion (120) thereof, a step surface is formed between the insertion portion (121) and the mating portion (120), and the step is in limited engagement with the step surface to limit the travel of the pushrod (12) in the second valve cavity (1001).
  3. 3. A hydraulic cylinder comprising an inner chamber, a piston assembly fitted in the inner chamber, and a valve assembly (1) according to claim 1 or 2, the inner chamber of the hydraulic cylinder being connected to a tank via the valve assembly (1).
  4. 4. A hydraulic cylinder according to claim 3, wherein the piston assembly comprises a piston (210) and a piston rod (211), the piston (210) is connected to one end of the piston rod (211), a guide sleeve (22) for guiding the piston rod (211) is arranged at an opening of the hydraulic cylinder (2) for the piston rod (211) to extend into, and the guide sleeve (22) seals an inner cavity of the hydraulic cylinder (2), the piston (210) divides the inner cavity of the hydraulic cylinder (2) into a rod cavity (200) for the piston rod (211) to stretch out and draw back, and a rodless cavity (201) positioned at one side of the piston (210) away from the piston rod (211); A third installation cavity (1001 c) is arranged between the second installation cavity (1001 b) and the plug (14), and the bottom of the matching part (120) of the push rod (12) is exposed in the third installation cavity (1001 c); The rod cavity (200) of the hydraulic cylinder (2) is connected with the first valve cavity (1000) of the valve assembly (1) through a liquid passage (24), and the rodless cavity (201) of the hydraulic cylinder (2) is connected with the third installation cavity (1001 c) of the valve assembly (1) through a rodless cavity channel (2011).
  5. 5. The hydraulic cylinder according to claim 4, wherein the valve body (10) is provided with a first liquid inlet and outlet channel (101) and a second liquid inlet and outlet channel (102) for connecting an oil tank, the first liquid inlet and outlet channel (101) is communicated with a third mounting cavity (1001 c) of the valve assembly (1), and the second liquid inlet and outlet channel (102) is communicated with a first mounting cavity (1001 a) of the valve assembly (1).
  6. 6. A hydraulic cylinder according to claim 3, characterized in that the non-return valve (11) is a non-return valve allowing fluid to flow only from the first mounting chamber (1001 a) to the first valve chamber (1000).
  7. 7. A hydraulic cylinder according to claim 3, characterized in that the centre lines of the first (1001 a), second (1001 b) and third (1001 c) mounting chambers coincide.
  8. 8. A hydraulic cylinder according to claim 3, characterized in that one side of the hydraulic cylinder (2) is provided with a knuckle bearing (23).

Description

Valve assembly and hydraulic cylinder Technical Field The utility model relates to the technical field of fluid pressure actuating mechanisms, in particular to a valve assembly and a hydraulic cylinder. Background In general, the effective working volumes in two cavities (generally called a rod cavity and a rodless cavity) of a hydraulic cylinder are quite different, and in order to achieve the purpose of preventing the piston and a piston rod of the hydraulic cylinder from sliding downwards, namely, ensuring the hydraulic cylinder to discharge oil quickly and simultaneously preventing hydraulic oil from flowing reversely under the pressure action of a hydraulic system, a one-way valve is arranged in a valve assembly of the hydraulic cylinder. The hydraulic control ratio of the check valve can affect the sensitivity of the hydraulic cylinder system, and is essentially the ratio of the acting area of the load pressure to the acting area of the control cavity pressure, and when the load pressure is used as the assisting force for opening the check valve, the opening pressure of the check valve is equal to the resistance of the check valve minus the load pressure, so that when the hydraulic control ratio of the check valve is larger, the opening pressure of the valve assembly is smaller. And vice versa. The existing check valve assembled on the hydraulic cylinder is usually an inserted check valve, and when the installation space of the check valve in the hydraulic cylinder is limited, only a small-size check valve can be selected. The small-volume one-way valve is limited by the volume of the valve, and the hydraulic control ratio can only be designed to be not more than 3:1, so that the sensitivity requirement of the hydraulic cylinder can not be met. Disclosure of Invention The utility model aims to develop a valve assembly and a hydraulic cylinder, so that the sensitivity of the hydraulic cylinder is improved by increasing the hydraulic control ratio of a one-way valve under the condition that the installation space of the one-way valve in the hydraulic cylinder is limited. The utility model is realized by the following technical scheme: In a first aspect, a valve assembly is provided, which comprises a valve body, a push rod, a reset spring and two plugs, wherein the valve body is provided with a first valve cavity and a second valve cavity, the two plugs are used for respectively blocking the first valve cavity opening and the second valve cavity opening which are positioned on two ends of the valve body, the second valve cavity comprises a first installation cavity connected with the first valve cavity and a second installation cavity connected with one end of the first installation cavity far away from the first valve cavity, the push rod comprises an insertion part in clearance fit with the inner side wall of the first installation cavity and a matching part in sliding sealing fit with the inner side wall of the second installation cavity, and the reset spring is sleeved on the insertion part of the push rod and limited between the first installation cavity and the matching part, and further comprises: The one-way valve is arranged between the first valve cavity and the first installation cavity, the one-way valve is a compression-expansion one-way valve, and the ratio of the cross section area of the matched part of the push rod to the cross section area of the valve hole of the one-way valve is more than 3 and less than 12. The cross section area of the valve hole of the one-way valve specifically refers to the cross section area of the valve hole of the one-way valve for controlling the on-off of fluid by using a valve ball. The hydraulic control ratio of the one-way valve is the ratio of the cross section area of the matching part on the push rod to the cross section area of the valve hole of the one-way valve, the hydraulic control ratio can be effectively improved by using the expansion one-way valve to replace the existing plug-in one-way valve in a hydraulic cylinder with small size and compact structure (particularly, the installation space of the one-way valve in the hydraulic cylinder is small), and the sensitivity of the hydraulic cylinder is further improved. In one possible implementation, the diameter of the first mounting cavity is smaller than that of the second mounting cavity, a step part is formed between the first mounting cavity and the second mounting cavity, the diameter of the insertion part of the push rod is smaller than that of the matching part of the push rod, a step surface is formed between the insertion part and the matching part, and the step part is in limit fit with the step surface to limit the moving stroke of the push rod in the second valve cavity. In a second aspect, there is also provided a hydraulic cylinder comprising an inner chamber, a piston assembly fitted in the inner chamber, and a valve assembly as described above, the inner chamber of the hydraulic c