Load limiting oil cylinder

Abstract

The utility model discloses a load limiting oil cylinder which comprises a cylinder body, a piston rod is arranged in the cylinder body, an oil cavity is formed between the cylinder body and the piston rod, an oil port communicated with the oil cavity is formed in the cylinder body, a threaded hole is formed in the cylinder body, a limiting part is arranged on the piston rod, a cut-off screw is screwed into the threaded hole, and the cut-off screw is screwed into the limiting part. The front end of the cut-off screw enters the limiting part to support the piston rod, and the fracture portion of the cut-off screw is located at the fit clearance of the piston rod and the cylinder body. By means of the mode, the load limiting oil cylinder can bear a certain load in a non-oil-pressure state, can normally operate after oil pressure is loaded, and is simple in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to the field of oil cylinders, in particular to a load-limiting oil cylinder. Background Art

[0002] The position of the cylinder is driven by hydraulic oil. If the cylinder needs to remain in a certain position, it needs to be locked by the hydraulic oil circuit or positioned by an external oil pressure locking device. Due to the gap in the hydraulic system circuit, the cylinder is prone to movement when the position is locked for a long time, and long-term use of supplementary pressure also results in a certain amount of energy consumption.

[0003] Conventional cylinders can only be locked in position by hydraulic oil, or by a locking cylinder mechanism that is locked by external oil pressure. When the hydraulic oil is not under pressure, the position can only be limited by the structure at both ends of the cylinder stroke. Summary of the invention

[0004] The main technical problem solved by the utility model is to provide a load-limiting oil cylinder which can bear a certain load in a state without oil pressure and can operate normally after oil pressure is loaded, has a simple structure and is easy to use.

[0005] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide a load limiting oil cylinder, including a cylinder body, a piston rod is arranged in the cylinder body, an oil chamber is formed between the cylinder body and the piston rod, an oil port connected to the oil chamber is opened on the cylinder body, a threaded hole is arranged on the cylinder body, a limiting portion is provided on the piston rod, a cutting screw is screwed into the threaded hole, the front end of the cutting screw enters the limiting portion to support the piston rod, and the breaking part of the cutting screw is located at the fitting gap between the piston rod and the cylinder body.

[0006] In a preferred embodiment of the utility model, the cutting screw includes a threaded column and a cutting column, the fracture site is located at the junction of the threaded column and the cutting column, the threaded column is cooperatively connected with the threaded hole, and the cutting column extends into the limiting portion.

[0007] In a preferred embodiment of the present invention, the threaded hole has a positioning step, and the screw head of the cut-off screw cooperates with the positioning step.

[0008] In a preferred embodiment of the present invention, the cutting column contacts the limiting portion in the axial direction and has a movable space between the cutting column and the limiting portion in the circumferential direction.

[0009] In a preferred embodiment of the present invention, the limiting portion is a pin hole or a groove formed on the surface of the piston rod.

[0010] In a preferred embodiment of the present invention, a limiting protrusion is provided between the piston rod and the inner wall of the cylinder body, the limiting protrusion is located above the threaded hole and the limiting portion, and there is a distance between the limiting protrusion and the threaded hole and the limiting portion.

[0011] In a preferred embodiment of the utility model, the oil port applies pressure to the oil chamber, thereby pressing down the cutting screw through the piston rod, and the cutting screw breaks from the breaking position after being pressed.

[0012] In a preferred embodiment of the present invention, the cutting screw is arranged radially.

[0013] The beneficial effects of the utility model are as follows: the load-limiting oil cylinder of the utility model mechanically limits the piston rod at a specified position by means of a cutting screw, thereby ensuring that the oil cylinder can still withstand a certain axial load when the piston rod is not subjected to the action of oil pressure; after the oil cylinder is mechanically limited, a certain pressure is applied to break the cutting screw, and the oil cylinder can still operate freely.

[0014] The utility model discloses a load-limiting oil cylinder, a cutting screw and a cylinder body cooperate with the thread and the positioning step structure design to ensure that the cutting position is at the gap, the cutting screw cooperates with the limiting part to limit the extension distance of the piston rod in the axial direction, and the piston rod has a certain swing space in the circumferential direction to meet the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0016] Figure 1 This is a structural schematic diagram of a preferred embodiment of the load limiting oil cylinder of the utility model;

[0017] Figure 2 yes Figure 1 Schematic diagram of the local structure;

[0018] Figure 3 It is a schematic diagram of the structure of the piston rod;

[0019] Figure 4 It is a schematic diagram of the structure of cutting off the screw;

[0020] The markings of the components in the accompanying drawings are as follows: 1. cylinder body, 11. oil chamber, 12. oil port, 13. threaded hole, 2. piston rod, 21. limiting part, 3. cutting screw, 31. threaded column, 32. cutting column, 33. fracture part. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiment of the utility model will be described clearly and completely below. The structure, proportion, size, etc. illustrated in the drawings of this specification are only used to match the content disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the limiting conditions that can be implemented in the utility model, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that can be produced by the utility model and the purpose that can be achieved, should still fall within the scope of the technical content disclosed in the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of narration, and are not used to limit the scope that can be implemented. The change or adjustment of its relative relationship should also be regarded as the scope that can be implemented in the utility model without substantially changing the technical content.

[0022] See also Figures 1 to 4 A load-limiting oil cylinder includes a cylinder body 1, a piston rod 2 is arranged in the cylinder body 1, an oil chamber 11 is formed between the cylinder body 1 and the piston rod 2, and an oil port 12 connected to the oil chamber 11 is opened on the cylinder body 1. Hydraulic oil is introduced into the oil port 12, and the oil pressure acts on the piston rod 2, so that the piston rod 2 moves downward. There is a limiting protrusion between the piston rod 2 and the inner wall of the cylinder body 1. When the piston rod 2 moves down a certain distance, the limiting protrusions are in contact with each other, and the piston moves to the maximum stroke.

[0023] The cylinder body 1 is provided with a threaded hole 13, and the piston rod 2 is provided with a limiting portion 21. When the piston rod 2 moves downward for a certain distance, the threaded hole 13 is aligned with the limiting portion 21. Since the limiting protrusion is located above the threaded hole 13 and the limiting portion 21, and there is a spacing between the limiting protrusion and the threaded hole 13 and the limiting portion 21, the piston rod 2 has not reached the maximum stroke at this time. The cutting screw 3 is screwed into the threaded hole 13, and the front end of the cutting screw 3 enters the limiting portion 21 to support the piston rod 2. The broken part 33 of the cutting screw 3 is located at the matching gap between the piston rod 2 and the cylinder body 1. In this case, the cutting screw 3 mechanically limits the piston rod 2. Even if there is no hydraulic oil in the oil port 12 at this time, the cutting screw 3 ensures that the piston rod 2 can withstand a certain axial load.

[0024] The cut-off screw 3 includes a threaded column 31 and a cut-off column 32. The fracture portion 33 is located at the junction of the threaded column 31 and the cut-off column 32. The threaded column 31 is connected with the threaded hole 13. The fracture portion 33 has a concave reduced diameter portion, which is easier to fracture. After the oil cylinder is mechanically limited, the oil port 12 presses the oil chamber 11. After a certain pressure is loaded, the piston rod 2 presses down the cut-off screw 3. The cut-off screw 3 is broken from the fracture portion 33 after being pressed. The cut-off screw 3 is broken at the fracture portion 33. At this time, the piston rod 2 can continue to move downward until it reaches the maximum stroke.

[0025] The cutting column 32 extends into the limiting portion 21. The threaded hole 13 has a positioning step, and the screw head of the cutting screw 3 cooperates with the positioning step. The positioning step and the threaded connection ensure that the cutting part is in the matching gap between the piston rod 2 and the cylinder body 1, so as to avoid the threaded column 31 interfering with the operation of the piston rod 2 after the cutting screw 3 breaks.

[0026] The cutting column 32 contacts the limiting part 21 in the axial direction and has a movable space between the limiting part 21 in the circumferential direction. The limiting part 21 is a pin hole or a groove opened on the surface of the piston rod 2. The cutting column 32 limits the piston rod 2 in the axial direction to ensure that it bears a certain axial load, and at the same time, the piston rod 2 has a certain rotation space in the circumferential direction. The pin hole can be a waist hole, a square hole, an elliptical hole or a round hole.

[0027] The cutting screw 3 is arranged radially. The cutting screw 3, the threaded hole 13 and the limiter 21 are designed according to the load requirements, and the number of the cutting screw 3, the threaded hole 13 and the limiter 21 can be multiple. By controlling the size of the bottom diameter of the groove of the fracture part 33, the fracture load is ensured to be T1±t, and the number is set to n according to the requirements. When there is no pressure in the oil chamber 11, the cylinder piston rod 2 can withstand an external load of about n*T1.

[0028] Different from the prior art, the load-limiting oil cylinder of the utility model can bear a certain load in a state without oil pressure, and can operate normally after being loaded with oil pressure, has a simple structure, and is easy to use.

[0029] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A load-limiting oil cylinder, comprising a cylinder body (1), a piston rod (2) being arranged in the cylinder body (1), an oil chamber (11) being formed between the cylinder body (1) and the piston rod (2), an oil port (12) being opened on the cylinder body (1) and communicating with the oil chamber (11), characterized in that: The cylinder body (1) is provided with a threaded hole, the piston rod (2) is provided with a limiting portion (21), a cutting screw (3) is screwed into the threaded hole (13), a front end of the cutting screw (3) enters the limiting portion (21) to support the piston rod (2), and a breaking portion (33) of the cutting screw (3) is located at a fitting gap between the piston rod (2) and the cylinder body (1).

2. The load limiting cylinder according to claim 1, characterized in that: The cutting screw (3) comprises a threaded column (31) and a cutting column (32), the fracture portion (33) is located at the junction of the threaded column (31) and the cutting column (32), the threaded column (31) is cooperatively connected with the threaded hole (13), and the cutting column (32) extends into the limiting portion (21).

3. The load limiting oil cylinder according to claim 2, characterized in that: The threaded hole (13) has a positioning step, and the screw head of the cutting screw (3) cooperates with the positioning step.

4. The load limiting oil cylinder according to claim 2, characterized in that: The cutting column (32) contacts the limiting portion (21) in the axial direction, and has a movable space between the cutting column and the limiting portion (21) in the circumferential direction.

5. The load limiting cylinder according to claim 4, characterized in that: The limiting portion (21) is a pin hole or a groove formed on the surface of the piston rod (2).

6. The load limiting oil cylinder according to claim 1, characterized in that: A limiting protrusion is provided between the piston rod (2) and the inner wall of the cylinder body (1); the limiting protrusion is located above the threaded hole (13) and the limiting portion (21), and there is a spacing between the limiting protrusion, the threaded hole (13) and the limiting portion (21).

7. The load limiting oil cylinder according to claim 6, characterized in that: The oil port (12) applies pressure to the oil chamber (11), thereby pressing down the cutting screw (3) through the piston rod (2); the cutting screw (3) is broken at the breaking position (33) after being pressed.

8. The load limiting oil cylinder according to any one of claims 1 to 7, characterized in that: The cutting screw (3) is arranged radially.

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