A hydraulic cylinder with a neutral position function

Abstract

This utility model relates to a hydraulic cylinder with a neutral position function, comprising a cylinder body, a first piston, and a second piston. The first and second pistons are movably fitted within a first piston accommodating cavity and a second piston accommodating cavity, respectively, dividing the interior of the cylinder body into a first oil chamber, a second oil chamber, and a third oil chamber. The cylinder body has three oil inlets. A middle push rod is provided between the first and second pistons. A piston rod is provided on the side of the second piston away from the first piston. The stroke of the first piston is less than the axial length of the middle push rod, and the sum of the stroke of the first piston and the axial length of the middle push rod is less than the stroke of the second piston. This utility model's hydraulic cylinder, by setting two independent pistons in different accommodating cavities within the cylinder body and using three oil inlets to control the pressure in the three oil chambers respectively, achieves left limit, neutral position, and right limit stop functions, improving control accuracy and starting smoothness.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, and in particular to a hydraulic cylinder with a neutral position function. Background Technology

[0002] A hydraulic cylinder, also known as a hydraulic actuator, is a hydraulic actuator that converts hydraulic energy into mechanical energy. It is mainly used to achieve linear reciprocating motion or oscillating motion. Conventional hydraulic cylinders only have two extreme positions, left and right. When the system pressure is released, the cylinder piston is in a free state, resulting in low stopping position accuracy of the actuator, a shocking feeling during startup, and poor starting smoothness.

[0003] Therefore, this utility model proposes a hydraulic cylinder with a neutral position function to solve the above problems. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a hydraulic cylinder with a mid-position function, which realizes the mid-position stop function, improves control accuracy and starting smoothness.

[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is: a hydraulic cylinder with a mid-position function, the innovation of which is: including a cylinder body, a first piston and a second piston;

[0006] The cylinder body has a first piston receiving cavity and a second piston receiving cavity that are interconnected. The first piston and the second piston are respectively movably fitted in the first piston receiving cavity and the second piston receiving cavity, and divide the inside of the cylinder body into a first oil cavity, a second oil cavity and a third oil cavity. The first oil cavity is located on the side of the first piston away from the second piston, the second oil cavity is located between the first piston and the second piston, and the third oil cavity is located on the side of the second piston away from the first piston. The cylinder body has three oil inlets, namely a first oil inlet communicating with the first oil cavity, a second oil inlet communicating with the second oil cavity, and a third oil inlet communicating with the third oil cavity.

[0007] An intermediate push rod is provided between the first piston and the second piston. One end of the intermediate push rod is fixed to the first piston, and the other end extends into the cavity of the second piston. A piston rod is provided on the side of the second piston away from the first piston. One end of the piston rod is fixed to the second piston, and the other end extends out of the cylinder body. The stroke of the first piston is less than the axial length of the intermediate push rod, and the sum of the stroke of the first piston and the axial length of the intermediate push rod is less than the stroke of the second piston.

[0008] Furthermore, the cylinder body includes a cylinder barrel, a left end cap, and a right end cap. A stepped through hole is axially opened in the middle of the cylinder barrel. The stepped through hole includes a first through hole section for forming a first piston accommodating cavity and a second through hole section for forming a second piston accommodating cavity. The left end cap and the right end cap are respectively installed at both ends of the cylinder barrel. The left end cap covers the second through hole section, and the inner end face of the left end cap forms a left limit position limiting surface. The right end cap covers the first through hole section, and the inner end face of the right end cap forms a right limit position limiting surface.

[0009] Furthermore, the inner diameter of the second through-hole section is smaller than the inner diameter of the first through-hole section, and the first through-hole section and the second through-hole section cooperate to form an intermediate position limiting step surface.

[0010] The advantages of this utility model are:

[0011] This invention relates to a hydraulic cylinder with two independent pistons housed in different cavities within the cylinder body. Three oil inlets control the pressure within each of the three cavities, thus controlling the smooth movement of the two pistons. When pressure is supplied through the third oil inlet while the first and second inlets are pressureless, the second piston, under pressure, moves its piston rod to the right, which in turn pushes the first piston to the right via a central push rod. The piston rod stops at its right limit position when the first piston reaches the right limit surface. Conversely, when pressure is supplied through both the first and third oil inlets while the second inlet is pressureless, and the third oil inlet... When the pressure at the first inlet is less than that at the second inlet, the first piston moves to the left under pressure, and the piston rod moves to the left via the intermediate push rod and the second piston. When the first piston hits the middle position limiting step surface, the piston rod stops at the middle position. When the second inlet is pressurized and oil enters, and the first and third inlets are not pressurized, the second piston moves the piston rod to the left under pressure. When the second piston hits the left limit position limiting surface, the piston rod moves to the left limit position, thus realizing the left limit, middle position, and right limit stop functions, improving control accuracy and starting smoothness. Attached Figure Description

[0012] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0013] Figure 1 This is a schematic diagram of the structure of the hydraulic cylinder with a center position function according to this utility model. Detailed Implementation

[0014] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0015] Example

[0016] This embodiment provides a hydraulic cylinder with a neutral position function, such as... Figure 1 As shown, it includes a cylinder block, a first piston 21, and a second piston 22.

[0017] The cylinder body has a first piston receiving cavity and a second piston receiving cavity that are interconnected. In this embodiment, the cylinder body includes a cylinder barrel 11, a left end cap 12, and a right end cap 13. A stepped through hole is axially opened in the middle of the cylinder barrel 11. The stepped through hole includes a first through hole section 51 for forming the first piston receiving cavity and a second through hole section 52 for forming the second piston receiving cavity. The left end cap 12 and the right end cap 13 are respectively installed at both ends of the cylinder barrel 11. The left end cap 12 covers the second through hole section 52, and the inner end face of the left end cap 12 forms a left limit position limiting surface 43. The right end cap 13 covers the first through hole section 51, and the inner end face of the right end cap 13 forms a right limit position limiting surface 41. The inner diameter of the second through hole section 52 is smaller than the inner diameter of the first through hole section 51. The first through hole section 51 and the second through hole section 52 cooperate to form an intermediate position limiting step surface 42.

[0018] The first piston 21 is movably disposed within the first piston receiving cavity, and the outer wall of the first piston 21 is sealed and connected to the inner wall of the first through hole section 51. The second piston 22 is movably disposed within the second piston receiving cavity, and the outer wall of the second piston 22 is sealed and connected to the inner wall of the second through hole section 52. The first piston 21 and the second piston 22 divide the interior of the cylinder into a first oil chamber, a second oil chamber, and a third oil chamber. The first oil chamber is located on the side of the first piston 21 away from the second piston 22, the second oil chamber is located between the first piston 21 and the second piston 22, and the third oil chamber is located on the side of the second piston 22 away from the first piston 21. The cylinder has three oil inlets, namely a first oil inlet 31 communicating with the first oil chamber, a second oil inlet 32 ​​communicating with the second oil chamber, and a third oil inlet 33 communicating with the third oil chamber.

[0019] An intermediate push rod 23 is provided between the first piston 21 and the second piston 22. One end of the intermediate push rod 23 is fixed to the first piston 21, and the other end extends into the cavity of the second piston. A piston rod 24 is provided on the side of the second piston 22 away from the first piston 21. One end of the piston rod 24 is fixed to the second piston 22, and the other end extends out of the cylinder body through the perforation of the front end cover 12. The stroke of the first piston 21 is less than the axial length of the intermediate push rod 23, and the sum of the stroke of the first piston 21 and the axial length of the intermediate push rod 23 is less than the stroke of the second piston 22.

[0020] The hydraulic cylinder uses two independent pistons located in different accommodating chambers within its cylinder body. Three oil inlets control the pressure within each of the three chambers, thus controlling the smooth movement of the two pistons. When pressure is supplied through the third oil inlet 33, and there is no pressure at the first and second oil inlets 31 and 32, the second piston 22, under pressure, drives the piston rod 24 to the right, which in turn pushes the first piston 21 to the right via the intermediate push rod 23. When the first piston 21 reaches the right limit position limiting surface 41, the cylinder piston rod 24 stops at the right limit position. When pressure is supplied through the first and third oil inlets 31 and 33, and there is no pressure at the second oil inlet 32... When there is pressure, and the pressure at the third oil inlet 33 is less than the pressure at the first oil inlet 31, the first piston 21 moves to the left under pressure, and pushes the piston rod 24 to the left via the intermediate push rod 23 and the second piston 22. When the first piston 21 abuts against the intermediate position limiting step surface 42, the piston rod 24 stops moving to the intermediate position. When the second oil inlet 32 ​​is pressurized and oil enters, and there is no pressure at the first oil inlet 31 and the third oil inlet 33, the second piston 22 drives the piston rod 24 to move to the left under pressure. When the second piston 22 abuts against the left limit position limiting surface 43, the piston rod 24 moves to the left limit position.

[0021] The hydraulic cylinder of this invention realizes the functions of stopping at the left limit, middle position, and right limit, thereby improving control accuracy and starting smoothness.

[0022] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A hydraulic cylinder with a neutral position function, characterized in that: Includes the cylinder block, the first piston, and the second piston; The cylinder body has a first piston receiving cavity and a second piston receiving cavity that are interconnected. The first piston and the second piston are respectively movably fitted in the first piston receiving cavity and the second piston receiving cavity, and divide the inside of the cylinder body into a first oil cavity, a second oil cavity and a third oil cavity. The first oil cavity is located on the side of the first piston away from the second piston, the second oil cavity is located between the first piston and the second piston, and the third oil cavity is located on the side of the second piston away from the first piston. The cylinder body has three oil inlets, namely a first oil inlet communicating with the first oil cavity, a second oil inlet communicating with the second oil cavity, and a third oil inlet communicating with the third oil cavity. An intermediate push rod is provided between the first piston and the second piston. One end of the intermediate push rod is fixed to the first piston, and the other end extends into the cavity of the second piston. A piston rod is provided on the side of the second piston away from the first piston. One end of the piston rod is fixed to the second piston, and the other end extends out of the cylinder body. The stroke of the first piston is less than the axial length of the intermediate push rod, and the sum of the stroke of the first piston and the axial length of the intermediate push rod is less than the stroke of the second piston.

2. The hydraulic cylinder with a neutral position function according to claim 1, characterized in that: The cylinder body includes a cylinder barrel, a left end cap, and a right end cap. A stepped through hole is axially opened in the middle of the cylinder barrel. The stepped through hole includes a first through hole section for forming a first piston accommodating cavity and a second through hole section for forming a second piston accommodating cavity. The left end cap and the right end cap are respectively installed at both ends of the cylinder barrel. The left end cap covers the second through hole section, and the inner end face of the left end cap forms a left limit position limiting surface. The right end cap covers the first through hole section, and the inner end face of the right end cap forms a right limit position limiting surface.

3. The hydraulic cylinder with a neutral position function according to claim 2, characterized in that: The inner diameter of the second through-hole section is smaller than that of the first through-hole section, and the first through-hole section and the second through-hole section cooperate to form a limiting step surface at the intermediate position.

Images