CN212250685U - Hydraulic buffer cylinder - Google Patents

Abstract

The utility model relates to the field of hydraulic oil cylinders, in particular to a hydraulic buffer oil cylinder, which is provided with a buffer device at least at one end of a cylinder body, and the buffer device comprises a signal plug, a signal cavity, a valve core, a valve hole and a return spring, Three annular oil grooves extending radially outward from the surface of the valve hole are arranged in the valve holes in sequence along the axial direction at a certain distance: valve hole oil groove I, valve hole oil groove II and valve hole oil groove III, and the valve core is provided with a valve in the middle position. The core ring groove, the two ends of the valve core ring groove are also provided with an unloading groove and a throttling groove, a damping hole and a spring cavity are set at the center of the valve core, and one end of the return spring is installed in the spring cavity of the valve core. The buffer oil cylinder involved has a more simplified buffer structure, good manufacturability, reduced manufacturing difficulty and manufacturing cost, easy quality assurance, convenient mass production, optimized structural settings of the valve core and valve hole, and improved the adjustment of the buffer device. performance, high cushioning smoothness and good cushioning effect.

Description

Hydraulic buffer cylinder

technical field

The utility model relates to the field of hydraulic oil cylinders, in particular to a hydraulic buffer oil cylinder.

Background technique

Hydraulic cylinder is the key executive component of the hydraulic system of construction machinery, which provides power for the working mechanism of construction machinery and completes various operation cycles, such as shovelling operations of loaders and excavation operations of excavators. The utility model is further optimized on the basis of the CN201610419750.1 utility model patent, and mainly optimizes the structural arrangement of the valve core and valve hole of the buffer device in the hydraulic buffer cylinder, improves the adjustment performance and steady-state characteristics of the buffer device, and simplifies the The structure is improved, the processing technology performance is improved, and the mass production of products is facilitated.

Utility model content

The main purpose of the utility model is to provide a hydraulic buffer cylinder to solve the problems in the prior art that the hydraulic cylinder buffer valve has low adjustment performance and steady state characteristics, complex structure, difficult processing and high cost.

In order to achieve the above object, the utility model adopts the following technical scheme:

A hydraulic buffer oil cylinder, comprising a guide sleeve, a cylinder head flange, a cylinder barrel, a piston, a piston rod, and a cylinder bottom. The cylinder head flange and the cylinder bottom are respectively fixed at both ends of the cylinder barrel to form a cylinder body, and the guide sleeve passes through a guide hole. Slide fit on the piston rod, the piston is fixedly connected to one end of the piston rod to form a piston rod assembly and slide fit in the cylinder barrel, the guide sleeve is fixedly connected with the cylinder head flange, and the cylinder barrel is clamped between the guide sleeve and the cylinder bottom , the piston divides the inner cavity of the cylinder into two cylinder chambers, chamber I and chamber II, which can be used as the oil inlet chamber and the oil return chamber of the oil cylinder respectively. When one of them is used as the oil inlet chamber of the oil cylinder When the high pressure oil is fed, the other one will be used as the oil return chamber of the oil cylinder to return the oil at low pressure. A buffer device is provided. The buffer device includes a signal plug, a signal cavity, a valve core, a valve hole and a return spring. The valve hole and the signal cavity are arranged at the end of the cylinder body, and the signal plug is correspondingly arranged on the piston rod assembly. Three annular oil grooves extending radially outward from the surface of the valve hole are arranged in parallel in the axial direction at a certain distance: valve hole oil groove I, valve hole oil groove II and valve hole oil groove III, valve hole oil groove III and the oil cylinder at the corresponding end of the buffer device The chamber is connected, the valve hole oil groove I is connected with the oil cylinder chamber at the other end of the cylinder block, and the oil inlet and outlet of the oil cylinder chamber are set on the corresponding valve hole oil groove II; The two sides of the core ring groove are also provided with an unloading groove and a throttling groove respectively, and the unloading groove and the throttling groove are connected with the valve core ring groove; a damping hole and a spring cavity are arranged at the center of the valve core, and the damping hole is located on the valve core One end of the throttling groove is provided, and the spring cavity is set at the other end of the valve core. The valve core ring groove is connected to the spring cavity end of the valve core through the oil passage, and at the same time, it passes through the damping hole and the valve core drive cavity at the other end of the valve core. Through; the valve core is assembled in the valve hole, the valve core driving cavity and the valve core spring cavity are respectively located at both ends of the valve core, the end of the valve core with the damping hole faces the valve core driving cavity, and one end of the return spring is installed on the valve core. In the spring cavity, the other end is pressed against the parts at the bottom of the valve hole, and the valve core and the return spring are constrained in the valve hole. Under normal conditions, the valve core is provided with damping under the thrust of the return spring. One end of the hole is pressed against the bottom part of the valve core drive cavity. At this time, the valve core throttle groove corresponds to the position of the valve hole oil groove III. The valve hole oil groove II and the valve hole oil groove III are normally connected through the valve core ring groove. The valve port is in a normal open state with a large valve opening, and the corresponding cylinder chamber can be communicated with the oil inlet and outlet of the cylinder chamber through the valve hole oil groove III, the main valve port, and the valve hole oil groove II; at the same time, the valve The hole oil groove I is in a state that is completely closed by the outer surface of the valve core, the oil communication path between the valve hole oil groove I and the valve hole oil groove II is completely cut off, and the valve core unloading groove and the valve hole oil groove I are in a state of disconnection ; The signal cavity is correspondingly set on the parts at the end of the cylinder body, and communicates with the spool drive cavity of the valve hole through the signal oil passage; the signal plug is correspondingly set on the piston rod assembly, and can be moved in or out with the movement of the piston The corresponding signal cavity can be kept in a sliding fit or separation state with the corresponding signal cavity.

Further, the buffer device is arranged at the end of the chamber I, and the valve hole and the signal chamber are arranged on the guide sleeve to realize the buffering of the oil cylinder at the end of the chamber I.

Further, the buffer device is arranged at the end of the chamber II, and the valve hole and the signal chamber are arranged on the bottom of the cylinder to realize the buffering of the oil cylinder at the end of the chamber II.

Further, both ends of the oil cylinder are provided with buffer devices, the valve hole and the signal cavity of the buffer device at the cavity I end are arranged on the guide sleeve, and the valve hole and the signal cavity of the buffer device at the cavity II end are arranged on the bottom of the cylinder, which can be respectively Realize the buffering of the oil cylinder at the cavity I end and the cavity II end.

Further, the relief groove and/or the throttling groove is a shallow and narrow elongated structure.

Further, the unloading groove and/or the throttling groove is an inclined surface inclined at a certain angle along the surface of the valve core, and the inclined surface is inclined from the outside to the direction of the ring groove of the valve core.

Further, the relief groove and/or the throttling groove is a radial hole communicating with the through oil passage.

Further, the unloading groove and/or the throttling groove is a shallow and narrow elongated structure, the cross section is a variable cross section, and the cross section area starts from the spool ring groove and gradually decreases from large to outward.

Further, the width of the relief groove and/or the throttling groove is in the range of 1-12 mm, and the range of the groove depth is in the range of 0.1-4 mm.

Further, the value range of the valve core driving ratio is 0.5-1.5, the diameter of the damping hole is 0.8-3mm, and the stiffness range of the return spring is 2-10N/mm.

The utility model has the following beneficial effects:

(1) Compared with the traditional hydraulic cylinder, the buffer structure of the hydraulic buffer cylinder is more simplified, the manufacturability is good, the manufacturing difficulty and manufacturing cost are reduced, the quality is easy to ensure, and it is convenient for mass production;

(2) The structural settings of the valve core and the valve hole are optimized, the adjustment performance of the buffer device is improved, the buffer stability is high and the buffer effect is good.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the hydraulic buffer cylinder of the present utility model, a buffer device is provided at the I end of the cylinder cavity, and the cylinder is in a non-buffer working state;

Fig. 2 is a schematic diagram of the structure principle of the hydraulic buffer cylinder of Fig. 1 in a buffer state, in which the direction of the liquid flow and the flow path in this state are indicated by arrows;

Fig. 3 is the three-dimensional structure schematic diagram of the valve core of Fig. 1;

Fig. 4 is a partial enlarged view at E of Fig. 2;

Fig. 5 is the deformation of Fig. 4, the unloading groove and the throttling groove of the valve core are set as small round holes;

6 is a schematic diagram of the structural principle of the utility model where the second end of the cylinder cavity is provided with a buffer device;

Fig. 7 is a schematic diagram of the bidirectional buffer structure principle of the hydraulic buffer cylinder of the present invention, and the large cavity I of the cylinder is provided with a buffer device.

Fig. 8 is a deformation of the valve core of Fig. 3. The unloading groove and the throttling groove of the valve core are inclined planes cut out along the surface of the valve core at a certain angle.

Wherein, the above drawings include the following reference numerals: 1, guide sleeve; 1-1, valve hole oil groove I; 1-2, valve hole oil groove II; 1-3, valve hole; 1-4, valve hole oil groove III; 1-5, signal oil passage; 1-6, guide hole; 1-7, cavity I oil passage; 1-8, cylinder bore positioning hole; 2, cylinder head flange; 3, cylinder bore; 4, signal plug; 5, piston; 6, piston rod; 7, cylinder bottom; 8, valve core; 8-1, spring cavity; 8-2, unloading groove; 8-3, valve core ring groove; 8-4, throttle groove ;8-5, through oil passage; 8-6, damping hole; 9, return spring; 10, valve cover; 11, fuel tank; X, signal chamber; J, pressure relief valve port; K, main valve port; A1 , cavity II oil port; A2, cavity II unloading port; B1, cavity I oil port; B2, cavity I unloading port; C, cavity I; D, cavity II; Q, spool drive cavity.

Detailed ways

The utility model will be further described below in conjunction with the accompanying drawings.

Example 1

As shown in Figure 1 and Figure 2, a hydraulic buffer cylinder is provided with a buffer device only at one end of the cavity I, and the buffer valve is integrated in the guide sleeve, which can realize the buffering of the cylinder at the end of the cavity I end of the cylinder when the piston approaches the end of the cylinder stroke. The main components of the hydraulic buffer cylinder include a guide sleeve, a cylinder head flange, a cylinder barrel, a piston, a piston rod, and a cylinder bottom. The cylinder head flange and the cylinder bottom are respectively fixed and connected to the two ends of the cylinder barrel to form an integral body; it also includes a signal plug 4, The signal plug and the piston are sequentially sleeved on the piston rod to form a piston rod assembly, the piston and the piston rod are fixedly connected, the signal plug is limited between the stepped surfaces of the piston and the piston rod, the piston is slidingly fitted in the cylinder barrel, and at the same time, the piston rod is The guide sleeve is slidably fitted in the guide hole of the guide sleeve, and further, the guide sleeve is sleeved on the cylinder barrel through the positioning holes 1-8 of the cylinder barrel, and is fixedly connected with the cylinder barrel through the cylinder head flange. The piston divides the cylinder chamber into chamber IID and chamber 1C. The chamber IID enters or discharges oil through the chamber II oil port A1, the chamber 1C enters or discharges oil through the chamber I oil port B1, and the chamber I unloads the oil from the chamber I port B2. Drain or enter oil. The guide sleeve is also provided with a signal cavity X, and the signal cavity can be paired with a corresponding signal plug arranged in the cavity IC to form a sliding fit. The guide sleeve is also provided with valve holes 1-3, and the valve holes are provided with annular valve hole oil groove I, valve hole oil groove II and valve hole oil groove III which are formed along the valve hole axial direction and are arranged in parallel along the valve hole axial direction. The hole oil groove I is connected with the cavity II discharge port A2 and the cavity II oil port A1, the valve hole oil groove II is connected with the cavity I oil port B1, the valve hole oil groove III is connected with the cavity 1C through the cavity I oil passages 1-7; it also includes the valve core 8 and return spring 9, as shown in Figure 3, the valve core is provided with a valve core ring groove 8-3, the valve core ring groove is an annular oil groove with a certain width and depth formed by expanding inward along the valve core surface. The two ends of the core ring groove are also provided with an unloading groove 8-2 and a throttling groove 8-4 respectively. The unloading groove and the throttling groove are formed by cutting material from the edge of the valve core ring groove along the axial direction on the valve core surface. The valve core is also provided with a damping hole 8-6 and a spring cavity 8-1. The damping hole is located at one end of the valve core where the throttle groove is provided, and the spring cavity is set at the other end of the valve core. The valve core ring The groove is connected to the end of the valve core with the spring cavity through the through oil passages 8-5, and at the same time, it is connected to the other end of the valve core through the damping hole; one end of the valve hole is fixed with the valve cover 10, and the other end is connected with the cylinder head flange. The valve core is fitted in the valve hole, one end of the return spring 9 is installed in the spring cavity of the valve core, and the other end is low pressure on the cylinder head flange. The valve core and the return spring are constrained to the valve cover and the cylinder head flange. In the normal working state, under the thrust of the return spring, the end of the valve core with the damping hole is low pressure on the valve cover. At this time, the valve hole oil groove II and the valve hole oil groove III pass through the valve core ring groove. Normal connection, the main valve port K is in the normal valve port opening state, and the cavity 1C can normally enter or discharge oil through the oil passage in the cavity I, the valve hole oil groove III, the main valve port K, the valve hole oil groove II and the cavity I oil port B1. At the same time, the valve hole oil groove I is completely closed by the outer surface of the valve core, and the communication oil path between the valve hole oil groove I and the valve hole oil groove II is completely cut off; the guide sleeve is also provided with a signal oil. Channels 1-5, the signal chamber communicates with the spool drive chamber Q through the signal oil channel.

The working principle of the hydraulic buffer cylinder is: as shown in Figure 1, when the high pressure oil enters the cavity IID through the cavity II oil port A1, the piston is driven by the high pressure oil in the cavity II to drive the piston rod assembly in the cylinder bore and guide. Under the joint guidance of the guide holes of the sleeve, it protrudes outward along the axis of the cylinder in the direction shown by the arrow in Figure 1. At the same time, the hydraulic oil in the cavity IC passes through the oil passages and valves in the cavity I under the pressure of the piston. Hole oil groove III, main valve port K, valve hole oil groove II and cavity I oil port B1 flow back to the oil tank 11; in the process of the piston rod extending outwards, the signal plug moves synchronously with the piston and gradually approaches the signal chamber. After the signal plug enters the signal cavity to form a sliding fit, as shown in Figure 2 and Figure 4, the oil in the signal cavity is isolated from the oil in the cavity IC, and is pushed by the signal plug with the movement of the piston to form The control signal pressure oil enters the valve core drive chamber Q through the signal oil passages 1-5. Part of this part of the control signal pressure oil will pass through the damping hole 8-6 on the valve core, the through oil passage 8-5, and the valve hole oil groove II. The oil is returned to the oil port B1 of the chamber I, and the rest pushes the spool to move against the resistance of the return spring, so as to adjust the opening of the main valve port K, so that the oil return throttling back pressure is generated in the chamber IC, and the oil is returned through the chamber I. The way of throttling back pressure controls the moving speed of the piston and realizes the buffer function of the oil cylinder; at the same time, the movement of the valve core will also open the pressure relief valve port J, so that the unloading groove 8-2 and the valve hole oil groove I1-1 The pressure oil in cavity IID can pass through cavity II oil port A1, cavity II unloading port A2, valve hole oil groove I, pressure relief valve port J, unloading groove 8-2, valve hole oil groove II and cavity I oil port B1 is communicated with the oil return tank. At this time, the cavity IID is in the unloading state. The cavity IID realizes the control of the piston movement speed through the unloading effect of the high pressure oil, and achieves the utility model through the oil return cavity throttling back pressure and high pressure. The dual function of cavity pressure relief and unloading can realize the purpose of cylinder buffering, energy saving and high efficiency. The movement state of the spool is dynamically controlled by the movement speed of the piston, so as to dynamically adjust the opening of the main valve port K and the pressure relief valve port J, and then dynamically adjust and control the pressure of the cylinder chamber 1C and chamber IID, which is realized by the dynamic control of the pressure. High-quality cushioning of the cylinder. When the piston reaches the end of the cylinder stroke and stops moving, the buffering ends, and the spool returns under the action of the return spring. When the piston needs to return in the reverse direction, the main valve of the hydraulic system (not shown in the figure) is operated to connect the chamber IC with the high-pressure oil, and the chamber IID is connected with the oil return tank, so as to realize the reverse movement of the oil cylinder, and the piston rod retract into the cylinder.

Example 2:

As shown in Figure 6, a hydraulic buffer cylinder has a buffer device only at one end of the chamber II, and the buffer valve is integrated on the bottom of the cylinder, which can realize the buffering of the cylinder at the end of the chamber II when the piston is close to the end of the cylinder stroke. Compared with Embodiment 1, the main difference is that both the valve hole and the signal cavity are arranged on the bottom of the cylinder, and the signal plug is a cylindrical structure arranged at the center of the bottom of the piston rod. Its working principle is similar to that of Embodiment 1. Here no more repetitions.

Example 3:

As shown in Fig. 7, a hydraulic buffer cylinder is provided with buffer devices at both ends of the cylinder, which can realize buffering when the piston at any end of the cylinder is close to the end of the stroke of the cylinder. This embodiment is the composite structure of Embodiment 1 and Embodiment 2, which can realize the bidirectional buffering function of the oil cylinder. During the working process of the oil cylinder, when the piston approaches the stroke end of one end of the oil cylinder, only the buffer device provided at this end is activated to play the buffer function.

Example 4:

The setting form of the unloading groove and the throttling groove of the valve core can also be changed in many ways. According to the needs, the adjustment performance of the groove can be changed by changing the depth, width, shape, position and cross-sectional shape of the groove. More excellent speed regulation characteristics, improve the buffer performance of the cylinder.

The relief grooves and throttle grooves shown in Figures 3 and 4 are shallow and narrow elongated structures, wherein the cross-section of the throttle groove is a variable cross-section, and its groove width starts from the spool ring groove 8-3 outwards and gradually increases from width to width. It narrows to the arc head. The bottom surface of the unloading groove is a step surface with different depths, and the groove depth at the end of the arc head is shallower, thereby improving the stability of unloading. The setting of the above unloading groove varies from width and depth. In one aspect, the variable section of the throttling groove is realized, which improves the buffer performance of the oil cylinder; the throttling groove is basically a structure of equal width and depth, in order to simplify the processing;

The unloading groove and the throttling groove shown in FIG. 5 are small radial holes communicating with the through oil passages 8-5, and the structure is simplified.

The unloading groove and the throttling groove shown in Figure 8 are inclined planes cut along the surface of the valve core at a certain angle, and the processing is simple.

The above is an introduction to the structure of Embodiments 1-4. Obviously, with reference to the guidance of schematic diagrams 1-8 and the introduction of the above-mentioned Embodiments 1-4, more embodiments can be changed, which will not be described in detail here.

It should be pointed out that the above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Obviously, according to actual needs, various changes can also be made, such as: changes in the structure of the valve core and valve hole, changes in the setting method of the signal cavity and signal plug, changes in oil ports and oil passages (position, direction, shape, form) etc.), the shape and position of the oil groove or the oil cavity, the change of the quantity, the structural change of the oil cylinder, etc.; there are also many changes in the setting form of the buffer elastic piece, for example, it can be assembled in the elastic cavity in the form of compression, but it can also be stretched. The form is set at the other end of the spool valve and has the same effect. Any person skilled in the art who is familiar with the technical scope disclosed by the present utility model, according to the principle diagram of the present utility model, the embodiment and its utility model concept, make equivalent replacements or changes, all should be included within the protection scope of the present utility model. .

Claims (10)

1. A hydraulic buffer oil cylinder, comprising a guide sleeve (1), a cylinder head flange (2), a cylinder barrel (3), a piston (5), a piston rod (6), a cylinder bottom (7), and a cylinder head flange (2) and the cylinder bottom (7) are respectively fixed on both ends of the cylinder (3) to form a cylinder body, the guide sleeve (1) is slidingly fitted on the piston rod (6) through the guide holes (1-6), the piston (5) ) is fixedly connected to one end of the piston rod (6) to form a piston rod assembly and is slidably fitted in the cylinder (3), the guide sleeve (1) is fixedly connected to the cylinder head flange (2), and the cylinder (3) is clamped Between the guide sleeve (1) and the cylinder bottom (7), the piston (5) divides the inner cavity of the cylinder into two oil cylinder chambers: cavity I (C) and cavity II (D). One end of the body is provided with a buffer device, the buffer device includes a signal plug (4), a signal cavity (X), a valve core (8), a valve hole (1-3) and a return spring (9), the valve hole (1-3) ) and the signal cavity (X) are arranged at the end of the cylinder body, the signal plug (4) is correspondingly arranged on the piston rod assembly, the valve holes (1-3) are arranged in sequence along the axial direction at a certain distance from the valve hole (1) -3) Three annular oil grooves extending radially outward from the surface: valve hole oil groove I (1-1), valve hole oil groove II (1-2) and valve hole oil groove III (1-4), valve hole oil groove III (1-4) (1-4) It is communicated with the cylinder chamber at the corresponding end of the buffer device, the valve hole oil groove I (1-1) is communicated with the cylinder chamber at the other end of the cylinder block, and the oil inlet and outlet of the cylinder chamber are arranged in the corresponding valve holes On the oil tank II (1-2); the valve core (8) is provided with a valve core ring groove (8-3) in the middle position, and the two sides of the valve core ring groove (8-3) are also provided with unloading grooves (8- 2) and the throttling groove (8-4), the unloading groove (8-2) and the throttling groove (8-4) are communicated with the valve core ring groove (8-3); the central position of the valve core (8) is provided with a The damping hole (8-6) and the spring cavity (8-1), the damping hole (8-6) is located at the end of the valve core (8) where the throttle groove (8-4) is arranged, and the spring cavity (8-1) It is arranged at the other end of the valve core (8), and the valve core ring groove (8-3) is connected to the end of the valve core spring cavity (8-1) through the through oil passage (8-5), and at the same time passes through the damping hole (8-1). -6) Connect with the spool drive cavity (Q) at the other end of the spool (8); the spool (8) is fitted in the valve hole (1-3), the spool drive cavity (Q) and the spool spring cavity (8-1) are located at both ends of the valve core (8) respectively, the valve core (8) with the damping hole (8-6) at one end facing the valve core drive chamber (Q), and the return spring (9) at one end installed on the valve core In the spring cavity (8-1) of the core (8), the other end is pressed against the parts at the bottom of the valve hole (1-3), the valve core (8) and the return spring (9) are constrained in the valve hole (1) In -3), the signal chamber (X) is correspondingly arranged on the parts at the end of the cylinder body, and communicates with the spool drive chamber (Q) of the valve hole (1-3) through the signal oil passage (1-5); The signal plug (4) is correspondingly arranged on the piston rod assembly, and can move into or out of the corresponding signal cavity (X) with the movement of the piston (5), so as to maintain a sliding fit with the corresponding signal cavity (X). state of union or separation. 2. A hydraulic buffer cylinder according to claim 1, characterized in that the buffer device is arranged at the end of the chamber I (C), and the valve hole (1-3) and the signal chamber (X) are arranged at the guide sleeve (1) , to realize the buffering of the cylinder at the end of cavity I (C). 3. A hydraulic buffer cylinder according to claim 1, characterized in that the buffer device is arranged at the end of chamber II (D), and the valve hole (1-3) and the signal chamber (X) are arranged at the bottom of the cylinder (7) , to realize the buffering of the oil cylinder at the end of cavity II (D). 4. A hydraulic buffer cylinder according to claim 1, characterized in that a buffer device is provided at both ends of the cylinder, the valve hole (1-3) of the buffer device at the end of cavity I (C) and the signal cavity ( X) is arranged on the guide sleeve (1), the valve hole (1-3) and the signal chamber (X) of the buffer device at the end of chamber II (D) are arranged on the cylinder bottom (7), so that the cylinder can be placed in the chamber I ( C) end and Cavity II (D) end of the buffer. 5. A hydraulic buffer cylinder according to any one of claims 1-4, wherein the relief groove (8-2) and/or the throttle groove (8-4) are shallow and narrow elongated structures . 6. A hydraulic buffer cylinder according to any one of claims 1-4, wherein the unloading groove (8-2) and/or the throttling groove (8-4) are a spool (8) along the valve core (8) The surface is inclined at a certain angle, and the inclined surface is inclined from the direction of the outward spool ring groove (8-3). 7. A hydraulic buffer cylinder according to any one of claims 1-4, wherein the unloading groove (8-2) and/or the throttling groove (8-4) are one and the through oil passage (8-4) -5) Connected radial holes. 8. A hydraulic buffer cylinder according to claim 5, characterized in that the unloading groove (8-2) and/or the throttle groove (8-4) are shallow and narrow elongated structures with a cross-section of Variable cross-section, its cross-sectional area gradually decreases from large to outward from the spool ring groove (8-3). 9. A hydraulic buffer cylinder according to claim 5, characterized in that the groove width of the unloading groove (8-2) and/or the throttle groove (8-4) ranges from 1 to 12 mm, and the groove depth ranges from 1 to 12 mm. The range is 0.1-4mm. 10. A hydraulic buffer cylinder according to any one of claims 1-4, characterized in that the value range of the valve core drive ratio is 0.5-1.5, and the diameter of the damping hole (8-6) is 0.8-3mm ; The stiffness range of the return spring (9) is 2-10N/mm.

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