Compound fast hydraulic cylinder

Abstract

The utility model discloses a composite fast hydraulic cylinder, wherein a piston rod is arranged in the inner cavity of a cylinder body, a filling valve installation port and a filling cavity are arranged at the upper end of the cylinder body, a cylinder body diaphragm is arranged between the filling cavity and the top of the piston rod, and a plurality of diaphragm through holes are evenly arranged on the cylinder body diaphragm; a downwardly extending fast cylinder is arranged at the center of the upper end face of the piston rod, a fast rod is arranged in the fast cylinder, the upper part of the fast rod passes through the fast rod guide sleeve and is sealed with each other, and the upper end of the fast rod passes through the center hole of the cylinder body diaphragm; a radially penetrating fast cylinder oil inlet hole is arranged along the radius of the cylinder body diaphragm, the inner port of the fast cylinder oil inlet hole is communicated with the annular oil groove on the outer periphery of the upper part of the fast rod, the annular oil groove is connected with the upper end of the central oil hole of the fast rod through the radial hole of the fast rod, and the central oil hole of the fast rod extends downward to the outlet of the lower end face of the fast rod. The hydraulic cylinder can improve the idle fast down speed and return speed of the slider without increasing the installed power.

Description

Technical Field

[0001] The utility model relates to a hydraulic cylinder for a hydraulic press, in particular to a composite fast hydraulic cylinder, belonging to the technical field of hydraulic cylinders. Background Art

[0002] With the development of technology, especially the automation application in various industries, the speed of the hydraulic presses that match it can no longer meet the requirements of industrial production, and people have put forward higher and higher requirements for the working speed of hydraulic presses. In the working process of general small and medium-sized hydraulic presses, the fast descent of the slider is achieved by the deadweight of the moving parts such as the slider and the mold. The speed is uncontrollable and has a large fluctuation range. There are many factors that affect the fast descent speed of the slider, mainly including: the weight of the slider mold of the moving parts, the clearance of the guide rail, the form and position tolerance of the guide rail surface, the lubrication of the guide rail surface, the tightness of the hydraulic cylinder seal ring, the oil temperature, the viscosity of the hydraulic oil, the size of the pipeline diameter, the short bending radius and direction, the diameter of the valve, etc. Therefore, there are many uncontrollable factors to make the fast descent speed of a hydraulic press meet the design requirements.

[0003] Furthermore, the traditional methods to increase the hydraulic press's quick-down speed include: increasing the diameter of the filling valve installed above the hydraulic cylinder, increasing the diameter of the hydraulic cylinder's lower chamber pipeline, and increasing the diameter of the main cylinder's lower chamber oil discharge cartridge valve to quickly drain the oil in the hydraulic cylinder's lower chamber, etc. However, this solution often cannot achieve the expected slider quick-down speed. For example, when the tonnage and table of the hydraulic press are very small, the weight of the moving parts is very small, and the friction ratio is high, the effect achieved by the above methods is often limited and uncontrollable, and it is also easy to cause other faults such as loose screws and pipe bursts due to large hydraulic shock. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0006] The purpose of the utility model is to overcome the problems existing in the prior art and provide a composite fast hydraulic cylinder, which can greatly improve the idle fast descending speed and return speed of the hydraulic press slide without increasing the installed power, thereby improving the working speed of the hydraulic press.

[0007] In order to solve the above technical problems, the utility model provides a composite fast hydraulic cylinder, comprising a cylinder body, a piston rod is provided in the inner cavity of the cylinder body, a main cylinder upper cavity oil port communicating with the cylinder body upper cavity is provided on the upper circumference of the cylinder body, a main cylinder lower cavity oil port communicating with the cylinder body lower cavity is provided on the lower circumference of the cylinder body, a filling valve installation port is provided at the upper end of the cylinder body, a filling cavity is provided below the filling valve installation port, a cylinder body diaphragm is provided between the filling cavity and the top of the piston rod, and a plurality of axially penetrating diaphragm through holes are evenly provided on the cylinder body diaphragm;

[0008] A quick cylinder extending downward to the middle and lower part of the piston rod is provided at the center of the upper end surface of the piston rod, a quick rod is provided in the quick cylinder, the upper part of the quick rod passes through the quick rod guide sleeve and is sealed with each other, the quick rod guide sleeve is embedded in the step hole of the upper port of the quick cylinder, and the upper end of the quick rod passes through the center hole of the cylinder body diaphragm;

[0009] A radially penetrating quick cylinder oil inlet hole is provided along the radius of the cylinder body cross partition, the inner port of the quick cylinder oil inlet hole is communicated with the annular oil groove on the outer periphery of the upper part of the quick rod, the annular oil groove is connected with the upper end of the quick rod center oil hole through the quick rod radial hole, and the quick rod center oil hole extends downward to the lower end surface outlet of the quick rod.

[0010] As an improvement of the utility model, the upper outer step of the quick rod guide sleeve abuts against the lower side of the clamping nut, and the outer circumference of the clamping nut is screwed into the upper end screw hole of the piston rod.

[0011] As a further improvement of the utility model, a quick rod convex ring is provided on the upper periphery of the quick rod, and the quick rod convex ring abuts against the bottom of the cylinder body cross partition. A small lock nut is screwed on the outer periphery of the upper end of the quick rod, and the bottom of the small lock nut is pressed on the upper surface of the cylinder body cross partition; a cylinder body lock nut is screwed on the upper external thread of the cylinder body.

[0012] As a further improvement of the utility model, a piston rod sealing section is provided on the upper part of the piston rod, which cooperates with the inner wall of the cylinder body and seals with each other, and a piston rod upper reduced diameter section is provided above the piston rod sealing section; the lower part of the piston rod passes through the cylinder port guide sleeve, and the cylinder port guide sleeve is fixed in the lower port of the cylinder body.

[0013] As a further improvement of the utility model, the lower end face of the cylinder body is fixed with a cylinder mouth flange by screws, the inner edge of the cylinder mouth flange is sealed with the lower circumference of the piston rod, the upper inner stop of the cylinder mouth flange is pressed on the lower outer step of the cylinder mouth guide sleeve; the piston rod flange is screwed on the outer circumference of the lower end of the piston rod.

[0014] As a further improvement of the utility model, the upper part of the piston rod is provided with an upper reduced diameter section of the piston rod, and the outer periphery of the upper reduced diameter section of the piston rod is sleeved with a piston rod sealing sleeve, the inner wall of the piston rod sealing sleeve is sealed with the outer periphery of the upper reduced diameter section of the piston rod through an O-ring, and the outer periphery of the piston rod sealing sleeve cooperates with the inner wall of the cylinder body and seals with each other; the bottom of the piston rod sealing sleeve abuts against the outer step of the upper reduced diameter section of the piston rod, and the upper end of the piston rod sealing sleeve is pressed with a large lock nut, and the large lock nut is screwed onto the outer periphery of the external thread at the upper end of the piston rod.

[0015] As a further improvement of the utility model, the oil port of the upper chamber of the master cylinder is located on the side wall of the liquid filling chamber or on the side wall of the cylinder body below the cylinder body diaphragm.

[0016] As a further improvement of the present invention, an upwardly extending center cylinder is provided at the center of the lower end surface of the piston rod, a center rod is provided in the center cylinder, a center rod sealing section is provided on the upper circumference of the center rod to achieve sealing with the inner wall of the center cylinder, the lower end of the center rod extends out of the center rod guide sleeve and is sealed with each other, the outer circumference of the center rod guide sleeve is screwed to the lower port of the center cylinder, an annular groove is provided at the lower outer circumference of the piston rod, a split piston rod flange is embedded in the annular groove, and the piston rod flange is fixed to the slider by screws.

[0017] As a further improvement of the utility model, an upper chamber oil port of the center cylinder and a lower chamber oil port of the center cylinder are respectively provided on the lower circumference of the piston rod. The lower chamber oil port of the center cylinder is directly connected with the lower chamber of the center cylinder in the radial direction, the upper chamber oil port of the center cylinder is connected with the axial oil hole of the center cylinder, and the upper part of the axial oil hole of the center cylinder is directly connected with the upper chamber of the center cylinder through the radial oil hole of the center cylinder.

[0018] Compared with the prior art, the utility model has achieved the following beneficial effects: 1. It can meet the installation requirements of large-diameter filling valves. By setting the cylinder body cross partition and the partition through holes and the quick cylinder oil inlet holes thereon, it can meet the requirements of both the quick cylinder oil filling and the large amount of liquid filling into the upper chamber of the main cylinder.

[0019] 2. When the tonnage and table surface of the hydraulic press are very small, the weight of the moving parts is very small, and the friction ratio is high, injecting a small flow of oil into the quick rod can push the piston rod to move quickly, which can overcome the defects of relying on the weight of the slider and the mold to achieve the slow speed of the slider and the large fluctuation range. At the same time, it can overcome the adverse effects of the uncontrollable slider speed caused by other external factors.

[0020] 3. In conjunction with the servo pump, the slider can also be accelerated and decelerated flexibly to achieve smooth acceleration at the beginning of high-speed movement and smooth deceleration at the end. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0022] Figure 1 This is a front view of the first embodiment of the composite fast hydraulic cylinder of the utility model;

[0023] Figure 2 for Figure 1 A top view of

[0024] Figure 3 for Figure 1 A cross-sectional view of the middle cylinder body;

[0025] Figure 4 for Figure 3 Sectional view along AA;

[0026] Figure 5 This is a front view of the second embodiment of the composite fast hydraulic cylinder of the utility model;

[0027] In the figure: 1. Cylinder body; 1a. Oil port of the upper chamber of the main cylinder; 1b. Installation port of the filling valve; 1c. Filling chamber; 1d. Cylinder body diaphragm; 1e. Diaphragm through hole; 1f. Quick cylinder oil inlet hole; 1g. Oil port of the lower chamber of the main cylinder;

[0028] 2. Piston rod; 2a. Oil port of the upper chamber of the center cylinder; 2b. Radial oil hole of the center cylinder; 2c. Oil port of the lower chamber of the center cylinder;

[0029] 3. Piston rod sealing sleeve; 4. Large lock nut; 5. Quick rod; 5a. Quick rod center oil hole; 6. Small lock nut; 7. Quick rod guide sleeve; 8. Pressing nut; 9. Cylinder port guide sleeve; 10. Cylinder port flange; 11. Piston rod flange; 12. Center rod; 13. Center rod guide sleeve; 14. Cylinder body lock nut. DETAILED DESCRIPTION

[0030] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0031] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] like Figures 1 to 4 As shown, the composite fast hydraulic cylinder of the utility model comprises a cylinder body 1, and a cylinder body lock nut 14 is screwed on the upper external thread of the cylinder body 1, which is used to fix the cylinder body 1 on the upper crossbeam. The inner cavity of the cylinder body 1 is provided with a piston rod 2, and the lower circumference of the cylinder body 1 is provided with a main cylinder lower chamber oil port 1g that communicates with the cylinder body lower chamber, and the upper end of the cylinder body is provided with a filling valve installation port 1b, and a filling chamber 1c is provided below the filling valve installation port 1b, and the side wall of the filling chamber 1c is provided with a main cylinder upper chamber oil port 1a that communicates with the cylinder body upper chamber. A cylinder body diaphragm 1d is provided between the filling chamber 1c and the top of the piston rod 2, and a plurality of axially penetrating diaphragm through holes 1e are evenly provided on the cylinder body diaphragm 1d.

[0034] A quick cylinder is provided at the center of the upper end surface of the piston rod 2 and extends downward to the middle and lower part of the piston rod 2. A quick rod 5 is provided in the quick cylinder. The upper part of the quick rod 5 passes through the quick rod guide sleeve 7 and is sealed with each other. The quick rod guide sleeve 7 is embedded in the step hole of the upper port of the quick cylinder. The upper outer step of the quick rod guide sleeve 7 abuts against the bottom of the clamping nut 8, and the outer circumference of the clamping nut 8 is screwed into the upper end screw hole of the piston rod 2.

[0035] A quick rod convex ring is provided on the upper periphery of the quick rod 5, and the quick rod convex ring abuts against the bottom of the cylinder body cross partition 1d. The upper end of the quick rod 5 passes through the central hole of the cylinder body cross partition 1d, and a small lock nut 6 is screwed on the outer periphery of the upper end. The bottom of the small lock nut 6 is pressed on the upper surface of the cylinder body cross partition 1d, thereby realizing axial fixation of the quick rod 5.

[0036] A radially penetrating quick cylinder oil inlet hole 1f is provided along the radius of the cylinder body cross partition 1d. The inner port of the quick cylinder oil inlet hole 1f is communicated with the annular oil groove on the upper outer periphery of the quick rod 5. The annular oil groove is connected with the upper end of the quick rod center oil hole 5a through the quick rod radial hole. The quick rod center oil hole 5a extends downward to the lower end surface outlet of the quick rod 5.

[0037] The piston rod 2 is provided with a piston rod sealing section on the upper part thereof, which cooperates with the inner wall of the cylinder body and seals with each other. The piston rod upper diameter reduction section is provided above the piston rod sealing section. The peripheral space of the piston rod upper diameter reduction section forms the upper cavity of the master cylinder, and the lower part of the piston rod sealing section forms the lower cavity of the master cylinder. The lower part of the piston rod 2 passes through the cylinder port guide sleeve 9, which is fixed in the lower port of the cylinder body.

[0038] The lower end surface of the cylinder body is fixed with a cylinder mouth flange 10 by screws, the inner edge of the cylinder mouth flange 10 is sealed with the lower circumference of the piston rod 2, and the upper inner stop of the cylinder mouth flange 10 is pressed on the lower outer step of the cylinder mouth guide sleeve 9; the piston rod flange 11 is screwed on the outer circumference of the lower end of the piston rod 2, and the piston rod flange 11 is connected to the slider by flange screws.

[0039] When the slider moves downward quickly in the idle stroke, oil is injected into the central oil hole 5a of the quick rod through the oil inlet hole 1f of the quick cylinder. The oil flows out from the lower end of the central oil hole 5a of the quick rod and enters the quick cylinder, and the quick cylinder pushes the piston rod 2 to move at high speed. Since the diameter of the quick rod is much smaller than the bore of the main cylinder, the hydraulic oil of the same flow rate first enters the quick rod 5 to push the piston rod 2 to move, which can obtain a higher movement speed, and the movement speed of the piston rod 2 can be accurately calculated based on the flow rate and the cross-sectional area of ​​the quick rod 5. With the servo pump, flexible acceleration and deceleration movement can also be achieved, so as to achieve the purpose of smooth acceleration of the slider at the beginning of high-speed movement and smooth deceleration at the end.

[0040] In this way, the slider is driven by power to achieve high-speed free travel and fast descent, which can overcome the adverse effects of other external factors. For example, when the guiding accuracy requirements are high, the guide rail gap is small and the friction resistance increases significantly, this fast cylinder can still achieve stable high-speed movement.

[0041] A cylinder body transverse partition 1d is provided in the cylinder body for installing the quick rod 5 and the quick cylinder oil inlet hole 1f. A large-diameter filling valve installation port 1b is provided at the upper end of the cylinder body for installing a large-diameter filling valve to solve the requirements of large-volume filling of the slider through the filling valve when the slider is in a high-speed idle stroke and large-flow oil replenishment through the filling valve when the slider is in a high-speed return stroke.

[0042] Four larger-diameter partition through holes 1e are processed on the upper part of the cylinder body transverse partition 1d to communicate with the upper cavity of the cylinder body to meet the demand for large flow.

[0043] The annular oil groove of the quick rod 5 is connected with the quick cylinder oil inlet hole 1f in the cylinder body diaphragm 1d, so that the quick rod 5 can be reliably connected with the quick cylinder oil inlet hole 1f when it rotates arbitrarily.

[0044] like Figure 5As shown, in another embodiment of the hydraulic cylinder, a piston rod upper diameter reduction section is provided on the upper part of the piston rod 2, and a piston rod sealing sleeve 3 is sleeved on the outer periphery of the piston rod upper diameter reduction section, and the inner wall of the piston rod sealing sleeve 3 is sealed with the outer periphery of the piston rod upper diameter reduction section through an O-ring, and the outer periphery of the piston rod sealing sleeve 3 matches and seals with the inner wall of the cylinder body; the bottom of the piston rod sealing sleeve 3 abuts against the outer step of the piston rod upper diameter reduction section, and a large lock nut 4 is pressed on the upper end of the piston rod sealing sleeve 3, and the large lock nut 4 is screwed on the outer periphery of the upper end external thread of the piston rod 2. The upper chamber oil port 1a of the master cylinder is located on the side wall of the cylinder body below the cylinder body diaphragm 1d.

[0045] A center cylinder extending upward is provided at the center of the lower end face of the piston rod 2, in which a center rod 12 is provided. A center rod sealing section is provided on the upper circumference of the center rod 12 to achieve sealing with the inner wall of the center cylinder. The lower end of the center rod 12 extends out from the center rod guide sleeve 13 and is sealed with each other. The outer circumference of the center rod guide sleeve 13 is screwed on the lower port of the center cylinder. An annular groove is provided on the lower outer circumference of the piston rod 2, in which a split piston rod flange 11 is embedded, and the piston rod flange 11 is fixed to the slider by screws.

[0046] The lower circumference of the piston rod 2 is provided with a center cylinder upper chamber oil port 2a and a center cylinder lower chamber oil port 2c respectively. The center cylinder lower chamber oil port 2c is directly connected with the lower chamber of the center cylinder in the radial direction, the center cylinder upper chamber oil port 2a is connected with the axial oil hole of the center cylinder, and the upper part of the axial oil hole of the center cylinder is directly connected with the upper chamber of the center cylinder through the center cylinder radial oil hole 2b.

[0047] A small central cylinder is arranged at the end of the piston rod 2, and a central rod 12 in the central cylinder can be extended or retracted relative to the piston rod 2, so as to realize punching or execute other process requirements.

[0048] When the slider moves down quickly: first fill the quick rod 5 with oil, open the filling valve, and replenish oil in the upper chamber of the master cylinder through the filling valve. The quick rod 5 does not move, and the oil entering the quick cylinder cavity of the piston rod 2 pushes the piston rod 2 to move quickly, realizing the high-speed free-range quick downward movement of the slider.

[0049] During the working process pressurization: the filling valve is closed, the lower chamber has back pressure, and the oil from the pump enters the upper chamber of the main cylinder to realize the working process pressurization of the slider. The quick rod 5 can be pressurized or not. When pressurized, oil is simultaneously injected into the upper chamber of the main cylinder and the quick rod 5; when not pressurized, the quick rod 5 does not enter oil, and the inner chamber of the quick cylinder forms a vacuum with the movement of the piston rod 2 and the slider, and the oil is self-primed through the one-way valve.

[0050] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A composite fast hydraulic cylinder, comprising a cylinder body, wherein the inner cavity of the cylinder body is provided with a piston rod, the upper circumference of the cylinder body is provided with a main cylinder upper cavity oil port communicating with the cylinder body upper cavity, and the lower circumference of the cylinder body is provided with a main cylinder lower cavity oil port communicating with the cylinder body lower cavity, characterized in that: A filling valve installation port is provided at the upper end of the cylinder body, a filling cavity is provided below the filling valve installation port, a cylinder body diaphragm is provided between the filling cavity and the top of the piston rod, and a plurality of axially penetrating diaphragm through holes are evenly provided on the cylinder body diaphragm; A quick cylinder extending downward to the middle and lower part of the piston rod is provided at the center of the upper end surface of the piston rod, a quick rod is provided in the quick cylinder, the upper part of the quick rod passes through the quick rod guide sleeve and is sealed with each other, the quick rod guide sleeve is embedded in the step hole of the upper port of the quick cylinder, and the upper end of the quick rod passes through the center hole of the cylinder body diaphragm; A radially penetrating quick cylinder oil inlet hole is provided along the radius of the cylinder body cross partition, the inner port of the quick cylinder oil inlet hole is communicated with the annular oil groove on the outer periphery of the upper part of the quick rod, the annular oil groove is connected with the upper end of the quick rod center oil hole through the quick rod radial hole, and the quick rod center oil hole extends downward to the lower end surface outlet of the quick rod.

2. The compound fast hydraulic cylinder according to claim 1, characterized in that: The upper outer step of the quick rod guide sleeve abuts against the lower side of the clamping nut, and the outer circumference of the clamping nut is screwed into the upper end screw hole of the piston rod.

3. The compound fast hydraulic cylinder according to claim 1, characterized in that: A quick rod convex ring is provided on the upper periphery of the quick rod, and the quick rod convex ring abuts against the bottom of the cylinder body diaphragm. A small lock nut is screwed on the outer periphery of the upper end of the quick rod, and the bottom of the small lock nut is pressed on the upper surface of the cylinder body diaphragm; a cylinder body lock nut is screwed on the upper external thread of the cylinder body.

4. The compound fast hydraulic cylinder according to claim 1, characterized in that: The upper part of the piston rod is provided with a piston rod sealing section which cooperates with the inner wall of the cylinder body and seals with each other, and the piston rod upper reduced diameter section is provided above the piston rod sealing section; the lower part of the piston rod passes through the cylinder port guide sleeve, and the cylinder port guide sleeve is fixed in the lower port of the cylinder body.

5. The compound fast hydraulic cylinder according to claim 4, characterized in that: The lower end surface of the cylinder body is fixed with a cylinder mouth flange by screws, the inner edge of the cylinder mouth flange is sealed with the lower circumference of the piston rod, the upper inner stop of the cylinder mouth flange is pressed on the lower outer step of the cylinder mouth guide sleeve; the piston rod flange is screwed on the outer circumference of the lower end of the piston rod.

6. The compound fast hydraulic cylinder according to claim 1, characterized in that: The upper part of the piston rod is provided with an upper reduced diameter section of the piston rod, and the outer periphery of the upper reduced diameter section of the piston rod is sleeved with a piston rod sealing sleeve. The inner wall of the piston rod sealing sleeve is sealed with the outer periphery of the upper reduced diameter section of the piston rod through an O-ring, and the outer periphery of the piston rod sealing sleeve cooperates with the inner wall of the cylinder body and seals with each other; the bottom of the piston rod sealing sleeve abuts against the outer step of the upper reduced diameter section of the piston rod, and the upper end of the piston rod sealing sleeve is pressed with a large lock nut, and the large lock nut is screwed onto the outer periphery of the external thread at the upper end of the piston rod.

7. The compound fast hydraulic cylinder according to claim 1, characterized in that: The oil port of the upper chamber of the master cylinder is located on the side wall of the liquid filling chamber or on the side wall of the cylinder body below the cylinder body diaphragm.

8. The compound fast hydraulic cylinder according to any one of claims 1 to 7, characterized in that: A center cylinder extending upward is provided at the center of the lower end surface of the piston rod, a center rod is provided in the center cylinder, a center rod sealing section is provided on the upper circumference of the center rod to achieve sealing with the inner wall of the center cylinder, the lower end of the center rod extends out of the center rod guide sleeve and is sealed with each other, the outer circumference of the center rod guide sleeve is screwed to the lower port of the center cylinder, an annular groove is provided at the lower outer circumference of the piston rod, a split piston rod flange is embedded in the annular groove, and the piston rod flange is fixed to the slider by screws.

9. The compound fast hydraulic cylinder according to claim 8, characterized in that: The lower circumference of the piston rod is respectively provided with an upper chamber oil port of the center cylinder and a lower chamber oil port of the center cylinder. The lower chamber oil port of the center cylinder is directly connected with the lower chamber of the center cylinder in the radial direction, and the upper chamber oil port of the center cylinder is connected with the axial oil hole of the center cylinder. The upper part of the axial oil hole of the center cylinder is directly connected with the upper chamber of the center cylinder through the radial oil hole of the center cylinder.

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