Two-stage thrust cylinder
By introducing a central tube and a narrowing oil passage into a single-stage hydraulic cylinder, combined with a movable locking key and a magnetostrictive displacement sensor, the problems of complex structure and unstable propulsion in existing two-stage hydraulic cylinders are solved, achieving simple, low-cost long-stroke propulsion and stable propulsion effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-03-06
AI Technical Summary
The existing two-stage hydraulic cylinders are complex in structure and costly in tunnel boring machines. Furthermore, the thrust and rigidity are uneven during the propulsion process, making it difficult to achieve a stable working state.
It adopts a single-stage hydraulic cylinder design, which achieves two-stage propulsion by setting a central tube and a shrinking oil passage inside the piston rod, combined with a movable key and a magnetostrictive displacement sensor, to ensure consistent thrust and rigidity.
It achieves long-stroke propulsion, simple structure, low cost, and no difference in thrust and rigidity during propulsion, meeting the requirements for stable working conditions.
Smart Images
Figure CN223975339U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a propulsion cylinder, and more particularly to a two-stage propulsion cylinder. Background Technology
[0002] Hydraulic cylinders are widely used in tunnel boring machines (TBMs). To achieve long-stroke propulsion of the front support plate of a TBM, two-stage cylinders are currently commonly used. This not only results in a more complex structure and higher cost, but also in the fact that the cross-sectional areas of the piston rods and pistons in the two stages are different, leading to differences in thrust and rigidity during the propulsion process, making it difficult to achieve a stable working state. Summary of the Invention
[0003] The purpose of this utility model is to address the aforementioned shortcomings of the existing technology by providing a two-stage propulsion cylinder. It can complete two-stage propulsion through a single-stage cylinder, which not only achieves long-stroke propulsion but also has a simple structure and low cost. In addition, the thrust and rigidity are the same during the propulsion process, which can meet the needs of stable working conditions.
[0004] To achieve the above objectives, this utility model provides a two-stage propulsion cylinder, comprising a cylinder bottom, a cylinder barrel, a guide sleeve, a piston rod, a rod head, and a piston; characterized in that a central tube with a radial clearance is fixedly disposed in the inner hole of the piston rod, and an extension port connected to the front end of the inner hole of the central tube is disposed in the rod head, the rear end of the inner hole of the central tube communicating with the rodless chamber behind the piston; the radial clearance between the central tube and the piston rod is a contraction chamber oil passage, a contraction chamber oil port connected to the front end of the contraction chamber oil passage is disposed in the rod head, a plug is fixedly disposed at the rear end of the contraction chamber oil passage, and a connecting oil passage connecting its inner hole and the rod chamber is disposed in the piston rod in front of the piston; a fixed flange is fixedly connected to the front end of the cylinder barrel, a pull-back keyway is disposed on the outer circle of the cylinder barrel behind the fixed flange, and a front keyway and a rear keyway are disposed on the outer circle of the cylinder bottom, a movable key engaging with the pull-back keyway, the front keyway, and the rear keyway.
[0005] In use, the workpiece is placed outside the cylinder behind the fixed flange, oil is introduced into the extension port, and the cylinder extends, thus performing the first stage of propulsion. Afterward, the cylinder retracts, the movable retaining key is placed in the front retaining key groove, the workpiece is then placed outside the cylinder bottom behind the movable retaining key, oil is introduced into the extension port, and the cylinder extends again, thus performing the second stage of propulsion. This utility model can complete two stages of propulsion with a single-stage hydraulic cylinder, which not only achieves long-stroke propulsion, but also has a simple structure and low cost. In addition, the thrust and rigidity are the same during the propulsion process, which can meet the needs of stable working conditions.
[0006] As a further improvement of this utility model, a bushing is fixed inside the cylinder bottom by a screw plug, and an electronic compartment for a magnetostrictive displacement sensor is installed inside the bushing by a wire ring. The cable connected to the electronic compartment passes through the screw plug. A support ring is fixed inside the piston rod on the rear side of the central tube. The support ring has several axial through holes, and a magnetic ring for a magnetostrictive displacement sensor is installed inside the support ring. The detection rod of the magnetostrictive displacement sensor passes through the magnetic ring and is placed inside the central tube; this can accurately detect the displacement of each stage of propulsion.
[0007] As a further improvement of this utility model, the movable locking key is fixedly connected to a handle; this facilitates the installation and removal of the sliding locking key.
[0008] As a further improvement of this utility model, the outer circumference of both the bushing and the electronic compartment is provided with a sealing ring; this can prevent oil leakage at the magnetostrictive displacement sensor.
[0009] In summary, this utility model can achieve two-stage propulsion through a single-stage hydraulic cylinder, which not only enables long-stroke propulsion but also features a simple structure and low cost. Furthermore, the thrust and rigidity remain unchanged during the propulsion process, thus meeting the requirements for stable operation. Attached Figure Description
[0010] Figure 1 This is a front view of an embodiment of the present utility model.
[0011] Figure 2 This is the front view of the active key in an embodiment of this utility model.
[0012] Figure 3 This is a front view of the first working state of this utility model embodiment.
[0013] Figure 4 This is a front view of the second working state of this utility model embodiment.
[0014] Figure 5 This is a front view of the third working state of this utility model embodiment. Detailed Implementation
[0015] The present invention will now be described in further detail with reference to the accompanying drawings.
[0016] like Figure 1 , Figure 2As shown, this embodiment of a two-stage propulsion cylinder includes a cylinder bottom 1 and cylinder barrel 2 welded together, a guide sleeve 3, a piston rod 4, a rod head 5, and a piston 6. A central tube 7 with a radial clearance is fixed in the inner hole of the piston rod 4. The front end of the central tube 7 is welded to the rod head 5. The rod head 5 has an extension port 8 connected to the front end of the inner hole of the central tube 7. The rear end of the inner hole of the central tube 6 communicates with the rodless chamber behind the piston 6. The radial clearance between the central tube 7 and the piston rod 4 is a constriction oil passage. The rod head 5 has a constriction oil port 9 connected to the front end of the constriction oil passage. A plug 10 is fixed at the rear end of the constriction oil passage. The rear end of the central tube 7 is welded to the piston rod 4. A connecting oil passage 11 connecting its inner hole and the rod chamber is provided in the piston rod 4 in front of the piston. A fixed flange 12 is welded to the front end of the cylinder barrel 2. The cylinder barrel has a pull-back keyway 13 on its outer circumference, and a front keyway 14 and a rear keyway 15 on its outer circumference. A movable key 16 is engaged with the pull-back keyway 13, the front keyway 14, and the rear keyway 15. A handle 17 is fixedly connected to the movable key 16. A bushing 19 is fixed inside the cylinder bottom 1 by a screw plug 18. An electronic compartment 22 of a magnetostrictive displacement sensor is installed inside the bushing 19 by a threaded ring 21. A cable 23 connected to the electronic compartment 22 passes through the screw plug 18. A support ring 26 is fixed inside the piston rod 4 on the rear side of the central tube 7 by a thread. The support ring 26 has several axial through holes 27. A magnetic ring 24 of a magnetostrictive displacement sensor is installed inside the support ring 26. The detection rod 25 of the magnetostrictive displacement sensor passes through the magnetic ring 24 and is placed inside the central tube 7. A sealing ring 28 or 29 is provided on the outer circumference of both the bushing 19 and the electronic compartment 22.
[0017] When using, such as Figure 3 As shown, the workpiece 31 is fitted onto the cylinder 2 behind the fixed flange 12, keeping the piston rod 4 and rod head 5 stationary. Oil enters through the extension port 8, the cylinder 2 extends, and the fixed flange 12 pushes the workpiece 31 backward, enabling a first-stage propulsion of the workpiece; then... Figure 4 As shown, oil is introduced into the shrinkage cavity oil port 9, causing the cylinder barrel 2 to retract. The workpiece 31 is located behind the front keyway 14. The movable key 16 is placed in the front keyway 14, and the workpiece 31 is then fitted onto the cylinder bottom 1 behind the movable key 16, as shown. Figure 5 As shown, oil is introduced into the extension port 8 and the cylinder 2 extends again, which can perform two-stage propulsion of the workpiece; when it is necessary to pull back the workpiece 31, the movable key 16 can be installed in the rear keyway 15 and the pull-back keyway 13 one after another, and oil is introduced into the shrinkage port 9, so that the cylinder bottom 1 and the cylinder 2 move forward and the movable key 16 drives the workpiece 31 back to its position.
[0018] This utility model can complete two-stage propulsion through a single-stage hydraulic cylinder, which not only achieves long-stroke propulsion, but also has a simple structure and low cost. In addition, the same piston rod 4 and piston 5 are used in the two-stage propulsion process, so there is no difference in their thrust and rigidity, which can meet the needs of stable working state.
[0019] During the two-stage propulsion process, the detection rod 25 of the magnetostrictive displacement sensor cooperates with the magnetic ring 24 to accurately detect the displacement of each stage of propulsion, which facilitates the control of the propulsion stroke; the sealing rings 28 and 29 can prevent oil leakage at the magnetostrictive displacement sensor.
Claims
1. A two-stage push oil cylinder comprising a cylinder bottom, a cylinder tube, a guide sleeve, a piston rod, a rod head and a piston; characterized in that The inner hole of the piston rod is fixed with a center tube arranged in a radial gap, the rod head is provided with an extension cavity oil port connected with the front end of the inner hole of the center tube, and the rear end of the inner hole of the center tube is communicated with a rodless cavity behind the piston; the radial gap between the center tube and the piston rod is a contraction cavity oil channel, the rod head is provided with a contraction cavity oil port connected with the front end of the contraction cavity oil channel, the rear end of the contraction cavity oil channel is fixed with a plug, the piston rod in front of the piston is provided with a connecting oil way communicated with the inner hole and a rod cavity; a fixed flange is fixed outside the front end of the cylinder barrel, a back-pulling key groove is arranged on the outer circle of the cylinder barrel at the rear side of the fixed flange, and front and rear key grooves are arranged on the outer circle of the cylinder bottom, and an active key is matched with the back-pulling key groove, the front key groove and the rear key groove.
2. A two-stage push oil cylinder as claimed in claim 1, characterized in that The inner hole of the cylinder bottom is fixed with a shaft sleeve through a screw plug, the shaft sleeve is provided with an electronic bin of a magnetic displacement sensor through a wire ring, a cable connected with the electronic bin passes through the screw plug, the piston rod at the rear side of the center tube is fixed with a support ring, the support ring is provided with a plurality of axial through holes, and the support ring is provided with a magnetic ring of the magnetic displacement sensor, and a detection rod of the magnetic displacement sensor passes through the magnetic ring and is arranged in the center tube.
3. A two-stage push oil cylinder according to claim 1 or 2, characterized in that The active key is fixed with a handle.
4. A two-stage push oil cylinder as claimed in claim 2, characterized in that The outer circles of the shaft sleeve and the electronic bin are both provided with sealing rings.