Composite structure multi-stage cylinder
Patent Information
- Application Number
- CN202522152137.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-11
- Publication Date
- 2026-09-08
- Estimated Expiration
- 2035-10-11
AI Technical Summary
然而，当主机结构限定必须将油口设置在缸筒的尾部或侧方时，上述经典结构便无法直接应用
本实用新型设计的多级缸，该油缸结构融合了两种过油方式：最内一级采用中空过油结构，避免了因开设过油孔而增大壁厚的问题；后续各级则利用双层缸筒间的环形夹层（间隙为3mm）实现过油。该结构在保持壁厚适中的同时，显著缩短了轴向尺寸。
Smart Images
Figure CN224729850U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of hydraulic cylinder technology, and in particular relates to a multi-stage cylinder with a composite structure. Background Technology
[0002] As industrial equipment becomes more compact and modular, the application scenarios for multi-stage hydraulic cylinders are becoming increasingly widespread. OEMs are imposing more stringent integrated installation requirements on the external structure of hydraulic cylinders, particularly the location and dimensions of the oil ports. This means that the radial and axial dimensions of the hydraulic cylinder must be controlled as much as possible while meeting specific oil port placement requirements.
[0003] For multi-stage hydraulic cylinders, a common and well-established hydraulic circuit design involves delivering the working fluid through an internal channel in the innermost piston rod, with the inlet and outlet ports located at the rod tip. This structure has a compact radial dimension and is an ideal design choice. However, when the host machine structure necessitates placing the ports at the rear or side of the cylinder, the aforementioned classic structure cannot be directly applied.
[0004] Secondly, the above solution has an inherent drawback: the rod head of the double-acting multi-stage cylinder moves along with the extension and contraction of the rod body. When the two oil port joints are designed at the rod head, the external connecting oil pipes must have high toughness and length. However, the characteristic of multi-stage cylinders is their long stroke, and the external connecting oil pipes need to slide with the rod head. Therefore, this may lead to wear and breakage of the external oil pipes, thus affecting the use of the multi-stage cylinder. Utility Model Content
[0005] In view of the technical problems existing in the background art, this utility model provides a composite structure multi-stage cylinder.
[0006] To achieve the above objectives, the technical solution provided by this utility model is as follows: A multi-stage composite cylinder includes a cylinder barrel and a cylinder bottom fixedly connected to the cylinder barrel. The cylinder barrel is provided with a piston assembly, which includes a sleeve assembly with a sandwich structure and a hollow piston assembly. The sleeve assembly includes an outer cylinder and an inner cylinder. A jacketed piston is provided at one end of the outer cylinder and the inner cylinder, and an annular jacketed oil passage cavity is formed between the outer cylinder and the inner cylinder. Jacketed oil passage holes are provided on the side of the outer cylinder near the jacketed piston and on the side of the inner cylinder away from the jacketed piston. The hollow piston assembly includes a third-stage piston rod, a fourth-stage piston rod, a third-stage piston, and a fourth-stage piston. One end of the third-stage piston rod is connected to the third-stage piston, and one end of the fourth-stage piston rod is connected to the fourth-stage piston. A hollow oil passage is provided inside the third-stage piston. The fourth-stage piston slides close to the outer wall of the hollow oil passage and the inner wall of the third-stage piston rod. An outer oil passage hole is provided on the side of the third-stage piston rod near the third-stage piston. A radial channel is formed on the third-stage piston to connect the hollow oil passage to the outer oil passage hole. A third axial oil passage is formed on the third-stage piston. An inner oil passage hole is formed on the side of the fourth-stage piston rod near the fourth-stage piston. The sleeve assembly is provided in several stages, and the sleeve assemblies are slidably fitted inwards in stages; the interlayer piston of the outermost sleeve assembly is slidably disposed on the inner wall of the cylinder, and the three-stage piston is slidably disposed on the inner wall of the inner cylinder of the innermost sleeve assembly.
[0007] Optionally, the sleeve assembly is provided in two parts, including a primary sleeve assembly and a secondary sleeve assembly. The primary sleeve assembly includes a primary outer cylinder and a primary inner cylinder. A primary jacketed piston is provided at one end of the primary outer cylinder and the primary inner cylinder. The primary outer cylinder and the primary inner cylinder form a primary annular jacketed oil passage cavity. A first jacketed oil passage hole is provided on the side of the primary outer cylinder near the primary jacketed piston, and a second jacketed oil passage hole is provided on the side of the primary inner cylinder away from the primary jacketed piston. The secondary sleeve assembly includes a secondary outer cylinder and a secondary inner cylinder. A secondary jacketed piston is provided at one end of the secondary outer cylinder and the secondary inner cylinder forms a secondary annular jacketed oil passage cavity. A third jacketed oil passage hole is provided on the side of the secondary outer cylinder near the secondary jacketed piston, and a fourth jacketed oil passage hole is provided on the side of the secondary inner cylinder away from the secondary jacketed piston.
[0008] Optionally, the cylinder is provided with an oil inlet and an oil outlet, which are located at opposite ends of the cylinder.
[0009] Optionally, the first-stage jacketed piston has a first axial oil passage inside, and the second-stage jacketed piston has a second axial oil passage inside.
[0010] Optionally, the inner diameter of the fourth-stage piston rod is larger than the outer diameter of the hollow oil passage.
[0011] Optionally, the cylinder is equipped with a hydraulic valve, and the outlet of the hydraulic valve is connected to the oil inlet and oil outlet through pipes.
[0012] This utility model has the following advantages and beneficial effects: This invention relates to a multi-stage cylinder that integrates two oil passage methods: the innermost stage employs a hollow oil passage structure, avoiding the problem of increased wall thickness due to the opening of oil passage holes; subsequent stages utilize an annular interlayer (with a 3mm gap) between the double-layer cylinder barrels to achieve oil passage. This structure significantly shortens the axial dimension while maintaining a moderate wall thickness.
[0013] By combining the advantages of two structures through a composite oil passage design, the cylinder diameter is reduced by approximately 15% and the length by approximately 20%, achieving a high degree of unity between structural compactness and performance optimization. While meeting the installation requirement of 'oil port located in cylinder body', the multi-stage 'sandwich oil passage' structure on the outer side, combined with the innermost 'hollow oil passage' structure, results in a multi-stage hydraulic cylinder that both meets the host interface specifications and maintains a compact shape. Attached Figure Description
[0014] Figure 1 This is a structural diagram of the composite multi-stage cylinder in the present invention in a retracted state; Figure 2 This is a structural diagram of the multi-stage composite cylinder in this utility model achieving the first-stage extended state; Figure 3 This is a structural diagram of the multi-stage composite cylinder in this utility model to achieve a two-stage extension state; Figure 4 for Figure 3 Enlarged view of the middle section structure; Figure 5 This is a structural diagram of the composite multi-stage cylinder in this utility model to achieve a three-stage extension state; Figure 6 for Figure 5 Enlarged view of the middle section structure; Figure 7 This is a structural diagram of the composite multi-stage cylinder in this utility model to achieve a four-stage extension state; Figure 8 for Figure 7 Enlarged view of the middle section structure; Figure 9 for Figure 7 A magnified view of a portion of point a; Figure 10 for Figure 7 A magnified view of a section at point b in the middle; Figure 11 for Figure 7 A magnified view of a section at point c in the middle; Figure 12 for Figure 7 A magnified view of a portion at point d.
[0015] Reference numerals: 1-Cylinder barrel, 11-Cylinder bottom, 12-Oil inlet, 13-Oil outlet, 14-Pipeline, 15-Hydraulic valve, 2-First-stage sleeve assembly, 2a-First-stage annular jacketed oil passage, 21-First-stage outer cylinder, 211-First jacketed oil passage hole, 22-First-stage inner cylinder, 221-Second jacketed oil passage hole, 23-First-stage jacketed piston, 231-First axial oil passage, 3-Second-stage sleeve assembly, 3a-Second-stage annular jacketed oil passage, 31-Second-stage... 311-Third interlayer oil passage, 32-Second stage inner cylinder, 321-Fourth interlayer oil passage, 33-Second stage interlayer piston, 331-Second axial oil passage, 4-Third stage piston rod, 4a-Innermost rodless cavity, 41-Third stage piston, 411-Outer layer oil passage, 42-Third axial oil passage, 43-Radial channel, 5-Fourth stage piston rod, 51-Fourth stage piston, 511-Inner layer oil passage, 6-Hollow oil passage pipe, 6a-Annular oil passage inner cavity. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.
[0017] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0018] Example like Figures 1-12 As shown, a multi-stage composite cylinder includes a cylinder barrel 1 and a cylinder bottom 11 fixedly connected to the cylinder barrel 1. The cylinder barrel 1 is provided with a piston assembly, which includes a sleeve assembly with a sandwich structure and a hollow piston assembly.
[0019] like Figure 1 As shown, the cylinder barrel 1 is provided with an oil inlet 12 and an oil outlet 13, which are located at both ends of the cylinder barrel 1.
[0020] like Figures 1-12 As shown, the sleeve assembly includes an outer cylinder and an inner cylinder. A jacketed piston is provided at one end of the outer cylinder and the inner cylinder. An annular jacketed oil passage cavity is formed between the outer cylinder and the inner cylinder, and the thickness of the oil passage cavity is 3mm. Jacketed oil passage holes are provided on the side of the outer cylinder near the jacketed piston and on the side of the inner cylinder away from the jacketed piston.
[0021] like Figures 1-12As shown, the hollow piston assembly includes a third-stage piston rod 4, a fourth-stage piston rod 5, a third-stage piston 41, and a fourth-stage piston 51. One end of the third-stage piston rod 4 is connected to the third-stage piston 41, and one end of the fourth-stage piston rod 5 is connected to the fourth-stage piston 51. A hollow oil passage 6 is provided inside the third-stage piston 41, and the fourth-stage piston 51 slides close to the outer wall of the hollow oil passage 6 and the inner wall of the third-stage piston rod 4. An outer oil passage hole 411 is provided on the side of the third-stage piston rod 4 near the third-stage piston 41. A radial channel 43 is provided on the third-stage piston 41 to connect the hollow oil passage 6 with the outer oil passage hole 411. A third axial oil passage 42 is provided on the third-stage piston 41. An inner oil passage hole 511 is provided on the side of the fourth-stage piston rod 5 near the fourth-stage piston 51.
[0022] like Figures 1-12 As shown, there are several sleeve assemblies, which are slidably fitted inwards in stages; the outermost sleeve assembly's interlayer piston is slidably mounted on the inner wall of the cylinder 1, and the third-stage piston 41 is slidably mounted on the inner wall of the inner cylinder of the innermost sleeve assembly.
[0023] This invention relates to a multi-stage cylinder that integrates two oil passage methods: the innermost stage employs a hollow oil passage structure, avoiding the problem of increased wall thickness due to the opening of oil passage holes; subsequent stages utilize an annular interlayer (with a 3mm gap) between the double-layer cylinder barrel 1 to achieve oil passage. This structure significantly shortens the axial dimension while maintaining a moderate wall thickness.
[0024] By combining the advantages of two structures through a composite oil passage design, the cylinder diameter is reduced by approximately 15% and the length by approximately 20%, achieving a high degree of unity between structural compactness and performance optimization. While meeting the installation requirement of 'oil port located in cylinder body', the multi-stage 'sandwich oil passage' structure on the outer side, combined with the innermost 'hollow oil passage' structure, results in a multi-stage hydraulic cylinder that both meets the host interface specifications and maintains a compact shape.
[0025] like Figure 1 As shown, in a preferred embodiment of this utility model, two sleeve assemblies are provided, including a primary sleeve assembly 2 and a secondary sleeve assembly 3.
[0026] like Figures 1-12 As shown, the first-stage sleeve assembly 2 includes a first-stage outer cylinder 21 and a first-stage inner cylinder 22. A first-stage jacketed piston 23 is provided at one end of the first-stage outer cylinder 21 and the first-stage inner cylinder 22. The first-stage outer cylinder 21 and the first-stage inner cylinder 22 form a first-stage annular jacketed oil passage 2a. A first jacketed oil passage hole 211 is provided on the side of the first-stage outer cylinder 21 near the first-stage jacketed piston 23, and a second jacketed oil passage hole 221 is provided on the side of the first-stage inner cylinder 22 away from the first-stage jacketed piston 23.
[0027] like Figures 1-12As shown, the secondary sleeve assembly 3 includes a secondary outer cylinder 31 and a secondary inner cylinder 32. A secondary jacketed piston 33 is provided at one end of the secondary outer cylinder 31 and the secondary inner cylinder 32. The secondary outer cylinder 31 and the secondary inner cylinder 32 form a secondary annular jacketed oil passage 3a. A third jacketed oil passage hole 311 is provided on the side of the secondary outer cylinder 31 near the secondary jacketed piston 33, and a fourth jacketed oil passage hole 321 is provided on the side of the secondary inner cylinder 32 away from the secondary jacketed piston 33.
[0028] like Figures 1-3 As shown, the first-stage jacketed piston 23 is slidably disposed on the inner wall of the cylinder 1, and the first-stage outer cylinder 21 and the cylinder 1 form a rodless cavity.
[0029] like Figures 1-3 As shown, the secondary jacketed piston 33 is slidably disposed on the inner wall of the primary inner cylinder 22, and a rodless cavity is formed between the secondary outer cylinder 31 and the primary inner cylinder 22.
[0030] like Figure 6 As shown, the third-stage piston 41 is slidably disposed on the inner wall of the second-stage inner cylinder 32, and a rodless cavity is formed between the third-stage piston rod 4 and the second-stage inner cylinder 32.
[0031] like Figure 6 As shown, the fourth-stage piston 51 slides close to the outer wall of the hollow oil pipe 6 and the inner wall of the third-stage piston rod 4, and the fourth-stage piston rod 5 and the third-stage piston rod 4 form the innermost rodless cavity 4a.
[0032] like Figures 1-3 As shown, the first-stage jacketed piston 23 has a first axial oil passage 231 inside, and the second-stage jacketed piston 33 has a second axial oil passage 331 inside.
[0033] like Figure 12 As shown, in this invention, the inner diameter of the fourth-stage piston rod 5 is larger than the outer diameter of the hollow oil passage 6, forming an annular oil passage cavity 6a between the fourth-stage piston rod 5 and the hollow oil passage 6. When the fourth-stage piston 51 slides against the outer wall of the hollow oil passage 6 and the inner wall of the third-stage piston rod 4, driving the fourth-stage piston rod 5 to extend, the oil in the innermost rodless cavity 4a can flow through the inner oil passage hole 511 into the annular oil passage cavity 6a between the fourth-stage piston rod 5 and the hollow oil passage 6, and flow from the end of the hollow oil passage 6 into the interior of the hollow oil passage 6. Finally, it flows through the radial channel 43, the outer oil passage hole 411, the fourth interlayer oil passage hole 321, the second-stage annular interlayer oil passage cavity 3a, the third interlayer oil passage hole 311, the second interlayer oil passage hole 221, the first-stage annular interlayer oil passage cavity 2a, the first interlayer oil passage hole 211, and the oil outlet 13, thereby realizing the return of hydraulic oil.
[0034] In this utility model, a hydraulic valve 15 is provided on the cylinder 1, and the outlet of the hydraulic valve 15 is connected to the oil inlet 12 and the oil outlet 13 through the pipe 14.
[0035] Hydraulic cylinder extension principle: like Figure 1 As shown, the hydraulic cylinder is in a folded and retracted state.
[0036] like Figure 2 As shown, in Figure 1 In the state shown, oil enters through the oil inlet 12, pushing all piston assemblies inside the cylinder 1 to extend synchronously. At this time, the oil between the cylinder 1 and the first-stage outer cylinder 21 flows back through the oil outlet 13, which is the first-stage extension state.
[0037] like Figure 3 As shown, when the first-stage sleeve assembly 2 is extended into position, Figure 2 In the state shown, oil enters through the inlet 12, and the oil pushes the secondary sleeve assembly 3 and the hollow piston assembly to extend synchronously through the first axial oil passage 231. At this time, the oil between the first-stage inner cylinder 22 and the second-stage outer cylinder 31 flows back through the second interlayer oil passage 221, the first-stage annular interlayer oil passage cavity 2a, the first interlayer oil passage 211, and the outlet 13, thus realizing the return of hydraulic oil, which is the second-stage extension state.
[0038] like Figure 5 As shown, when the secondary sleeve assembly 3 is extended into position, Figure 3 In the state shown, oil enters through the inlet 12, and the oil pushes the hollow piston assembly out through the second axial oil passage 331. At this time, the oil between the second-stage inner cylinder 32 and the fourth-stage piston rod 5 flows back through the fourth interlayer oil passage 321, the second-stage annular interlayer oil passage cavity 3a, the third interlayer oil passage 311, the second interlayer oil passage 221, the first-stage annular interlayer oil passage cavity 2a, the first interlayer oil passage 211, and the outlet 13, thus realizing the return of hydraulic oil, which is the third-stage extended state.
[0039] like Figure 7 As shown, when the third-stage piston rod 4 is fully extended, in Figure 5 In the indicated state, oil enters through inlet 12, and the oil pushes the fourth-stage piston 51 out through the third axial oil passage 42. At this time, the oil between the third-stage piston rod 4 and the fourth-stage piston rod 5 flows through the inner layer oil passage hole 511 into the annular oil passage cavity 6a between the fourth-stage piston rod 5 and the hollow oil passage pipe 6, and flows from the end of the hollow oil passage pipe 6 into the interior of the hollow oil passage pipe 6. Finally, it flows through the radial channel 43, the outer layer oil passage hole 411, the fourth interlayer oil passage hole 321, the second-stage annular interlayer oil passage cavity 3a, the third interlayer oil passage hole 311, the second interlayer oil passage hole 221, the first-stage annular interlayer oil passage cavity 2a, the first interlayer oil passage hole 211, and the outlet 13, thereby realizing the return of hydraulic oil, which is the fourth-stage extended state.
[0040] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A multi-stage cylinder with a composite structure, characterized in that: Includes a cylinder barrel and a cylinder bottom fixedly connected to the cylinder barrel, wherein a piston assembly is provided inside the cylinder barrel, and the piston assembly includes a sleeve assembly with a sandwich structure and a hollow piston assembly; The sleeve assembly includes an outer cylinder and an inner cylinder, and a jacketed piston is provided at one end of the outer cylinder and the inner cylinder. An annular jacketed oil passage cavity is formed between the outer cylinder and the inner cylinder. The outer cylinder is provided with an oil passage hole on the side near the jacketed piston and the inner cylinder is provided with an oil passage hole on the side away from the jacketed piston. The hollow piston assembly includes a third-stage piston rod, a fourth-stage piston rod, a third-stage piston, and a fourth-stage piston. One end of the third-stage piston rod is connected to the third-stage piston, and one end of the fourth-stage piston rod is connected to the fourth-stage piston. A hollow oil passage is provided inside the third-stage piston. The fourth-stage piston slides close to the outer wall of the hollow oil passage and the inner wall of the third-stage piston rod. An outer oil passage hole is provided on the side of the third-stage piston rod near the third-stage piston. A radial channel is formed on the third-stage piston to connect the hollow oil passage to the outer oil passage hole. A third axial oil passage is formed on the third-stage piston. An inner oil passage hole is formed on the side of the fourth-stage piston rod near the fourth-stage piston. The sleeve assembly is provided in several stages, and the sleeve assemblies are slidably fitted inwards in stages; the interlayer piston of the outermost sleeve assembly is slidably disposed on the inner wall of the cylinder, and the three-stage piston is slidably disposed on the inner wall of the inner cylinder of the innermost sleeve assembly.
2. The composite structure multi-stage cylinder according to claim 1, characterized in that: The sleeve assembly comprises two parts: a primary sleeve assembly and a secondary sleeve assembly. The primary sleeve assembly includes a primary outer cylinder and a primary inner cylinder. A primary jacketed piston is provided at one end of the primary outer cylinder and the primary inner cylinder. The primary outer cylinder and the primary inner cylinder form a primary annular jacketed oil passage cavity. A first jacketed oil passage hole is provided on the side of the primary outer cylinder near the primary jacketed piston, and a second jacketed oil passage hole is provided on the side of the primary inner cylinder away from the primary jacketed piston. The secondary sleeve assembly includes a secondary outer cylinder and a secondary inner cylinder. A secondary jacketed piston is provided at one end of the secondary outer cylinder and the secondary inner cylinder forms a secondary annular jacketed oil passage cavity. A third jacketed oil passage hole is provided on the side of the secondary outer cylinder near the secondary jacketed piston, and a fourth jacketed oil passage hole is provided on the side of the secondary inner cylinder away from the secondary jacketed piston.
3. The composite structure multi-stage cylinder according to claim 1, characterized in that: The cylinder is provided with an oil inlet and an oil outlet, which are located at opposite ends of the cylinder.
4. The composite structure multi-stage cylinder according to claim 2, characterized in that: The first-stage jacketed piston has a first axial oil passage inside, and the second-stage jacketed piston has a second axial oil passage inside.
5. The composite structure multi-stage cylinder according to claim 1, characterized in that: The inner diameter of the fourth-stage piston rod is larger than the outer diameter of the hollow oil passage.
6. The composite structure multi-stage cylinder according to claim 3, characterized in that: The cylinder is equipped with a hydraulic valve, and the outlet of the hydraulic valve is connected to the oil inlet and oil outlet through pipes.