CN111927848A

CN111927848A - Hydraulic buffer oil cylinder

Info

Publication number: CN111927848A
Application number: CN202010751295.1A
Authority: CN
Inventors: 朱德伟; 荣晓瑜
Original assignee: Qingdao Jizhi Innovation Technology Co ltd
Current assignee: Qingdao Jizhi Innovation Technology Co ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2020-11-13

Abstract

The invention relates to the field of hydraulic oil cylinders, in particular to a hydraulic buffer oil cylinder, wherein a buffer device is arranged at least at one end of a cylinder body, the buffer device comprises a signal plug, a signal cavity, a valve core, a valve hole and a return spring, and three annular oil grooves which are expanded outwards from the surface of the valve hole in the radial direction are sequentially arranged in parallel at certain intervals along the axial direction in the valve hole: valve opening oil groove I, valve opening oil groove II and valve opening oil groove III, case middle part position is provided with the case annular, the both ends of case annular still are provided with off-load groove and throttle groove respectively, case central point puts and is provided with damping hole and spring chamber, return spring one end is installed in the spring intracavity of case, this novel buffer cylinder that relates, its buffer structure simplifies more, the manufacturability is good, the manufacturing degree of difficulty and manufacturing cost have been reduced, the quality is guaranteed easily, the mass production of being convenient for, the case has been optimized, the structure setting of valve opening, buffer's accommodation performance has been improved, the buffering stationarity is high and buffering effect is good.

Description

Hydraulic buffer oil cylinder

Technical Field

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

Background

The hydraulic oil cylinder is a key execution component of a hydraulic system of the engineering machinery, and provides power for a working mechanism of the engineering machinery to complete various operation cycles, such as shoveling operation of a loader, excavating operation of an excavator and the like. The invention is further optimized on the basis of the patent of CN201610419750.1 invention, mainly optimizes the structural arrangement of a valve core and a valve hole of a buffer device in the hydraulic buffer oil cylinder, improves the adjustment performance and the steady-state characteristic of the buffer device, simplifies the structure, improves the processing technology performance and is beneficial to the batch production of products.

Disclosure of Invention

The invention mainly aims to provide a hydraulic buffer oil cylinder, which aims to solve the problems of low adjusting performance and steady-state characteristic, complex structure, difficult processing and high cost of a hydraulic buffer valve in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a hydraulic buffer oil cylinder comprises a guide sleeve, a cylinder head flange, a cylinder barrel, a piston rod and a cylinder bottom, wherein the cylinder head flange and the cylinder bottom are respectively fixed at two ends of the cylinder barrel to form a cylinder body, the guide sleeve is in sliding fit on the piston rod through a guide hole, the piston is fixedly connected with one end of the piston rod to form the piston rod assembly and is in sliding fit in the cylinder barrel, the guide sleeve is fixedly connected with the cylinder head flange, the cylinder barrel is clamped between the guide sleeve and the cylinder bottom, the piston divides an inner cavity of the cylinder body into two oil cylinder cavities, namely a cavity I and a cavity II, the cavity I and the cavity II can be sequentially used as an oil inlet cavity and an oil return cavity of the oil cylinder respectively, when high-pressure oil is introduced into the oil inlet cavity of the oil cylinder, the other oil cylinder is used as oil return cavity of the oil cylinder, the oil cylinder drives the piston to move through the matching of the high, buffer includes signal stopper, signal chamber, case, valve opening and return spring, and valve opening and signal chamber set up at the cylinder body tip, and the signal stopper then corresponds the setting on the piston rod subassembly, and the valve opening is provided with the three annular oil groove of radially outwards expanding from the valve opening surface along the axial at the interval certain distance side by side in proper order: the buffer device comprises a valve hole oil groove I, a valve hole oil groove II and a valve hole oil groove III, wherein the valve hole oil groove III is communicated with an oil cylinder cavity at the corresponding end of the buffer device, the valve hole oil groove I is communicated with the oil cylinder cavity at the other end of the cylinder body, and an oil inlet and an oil outlet of the oil cylinder cavity are arranged on the corresponding valve hole oil groove II; a valve core annular groove is formed in the middle of the valve core, an unloading groove and a throttling groove are formed in the two sides of the valve core annular groove respectively and are communicated with the valve core annular groove; the center of the valve core is provided with a damping hole and a spring cavity, the damping hole is positioned at one end of the valve core provided with a throttling groove, the spring cavity is arranged at the other end of the valve core, and the valve core ring groove is communicated with the spring cavity end of the valve core through a through oil duct and is communicated with a valve core driving cavity at the other end of the valve core through the damping hole; the valve core is assembled in the valve hole in a matching mode, the valve core driving cavity and the valve core spring cavity are respectively located at two ends of the valve core, one end, with a damping hole, of the valve core faces the valve core driving cavity, one end of a return spring is installed in the spring cavity of the valve core, the other end of the return spring abuts against a part at the bottom of the valve hole, the valve core and the return spring are restrained in the valve hole, under the normal state, one end, provided with the damping hole, of the valve core abuts against a part at the bottom of the valve core driving cavity under the thrust action of the return spring, at the moment, a throttling groove of the valve core corresponds to a position of a valve hole oil groove III, the valve hole oil groove II and the valve hole oil groove III are normally communicated through a valve core annular groove, a main valve port is in a normal opening; meanwhile, the valve hole oil groove I is in a state of being completely closed by the outer circle surface of the valve core, a communication oil 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 not being communicated; the signal cavity is correspondingly arranged on a part at the end part of the cylinder body and is communicated with the valve core driving cavity of the valve hole through a signal oil duct; the signal plug is correspondingly arranged on the piston rod assembly and can enter or move out of the corresponding signal cavity along with the movement of the piston, so that the signal plug can be in sliding fit with or separated from the corresponding signal cavity.

Furthermore, buffer sets up at I end in chamber, and valve opening and signal chamber set up on the uide bushing, realize the buffering of hydro-cylinder at I end in chamber.

Furthermore, the buffer device is arranged at the end of the cavity II, and the valve hole and the signal cavity are arranged on the cylinder bottom, so that the oil cylinder is buffered at the end of the cavity II.

Furthermore, both ends of the oil cylinder are provided with buffer devices, a valve hole and a signal cavity of the buffer device at the end I of the cavity are arranged on the guide sleeve, and a valve hole and a signal cavity of the buffer device at the end II of the cavity are arranged on the cylinder bottom, so that the oil cylinder can buffer the end I of the cavity and the end II of the cavity respectively.

Further, the relief grooves and/or the throttle grooves are shallow and narrow elongated structures.

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

Further, the unloading groove and/or the throttling groove are radial holes communicated with the through oil passages.

Furthermore, the unloading groove and/or the throttling groove are shallow and narrow long and narrow structures, the cross section is a variable section, and the section area of the unloading groove and/or the throttling groove gradually decreases from large to small from the valve core annular groove to the outside.

Furthermore, the groove width range of the unloading groove and/or the throttling groove is 1-12mm, and the groove depth range is 0.1-4 mm.

Furthermore, the value range of the valve core drive ratio is 0.5-1.5, and the diameter range of the damping hole is 0.8-3 mm; the rigidity range of the return spring is 2-10N/mm.

The invention has the following beneficial effects:

(1) compared with the traditional hydraulic oil cylinder, the hydraulic buffer oil cylinder has the advantages that the buffer structure is simplified, the manufacturability is good, the manufacturing difficulty and the manufacturing cost are reduced, the quality is easy to guarantee, and the batch production is convenient;

(2) the structure setting of case, valve opening has been optimized, buffer's accommodation performance has been improved, and buffering stationarity is high and buffering effect is good.

Drawings

FIG. 1 is a schematic diagram of the structural principle of a hydraulic buffer cylinder of the present invention, wherein a buffer device is arranged at the end I of a cylinder cavity, and the cylinder is in a non-buffer working state;

FIG. 2 is a schematic diagram of the hydraulic cushion cylinder of FIG. 1 in a cushion state, wherein the flow direction and flow path are indicated by arrows;

FIG. 3 is a schematic three-dimensional structure of the valve cartridge of FIG. 1;

FIG. 4 is an enlarged view of a portion of FIG. 2 at E;

FIG. 5 is a variation of FIG. 4, with the relief groove and the throttle groove of the valve core configured as a small circular hole;

FIG. 6 is a schematic view of the structural principle of the present invention in which a buffer device is disposed at the end II of the cylinder chamber;

FIG. 7 is a schematic diagram of the principle of the bidirectional buffering structure of the hydraulic buffering cylinder of the present invention, wherein the large chambers I of the cylinder are provided with buffering devices.

FIG. 8 is a variation of the valve cartridge of FIG. 3, with the relief groove and the throttling groove of the valve cartridge being a beveled surface cut at an angle along the surface of the valve cartridge.

Wherein the figures include the following reference numerals: 1. a 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, a signal oil duct; 1-6, a guide hole; 1-7, a cavity I oil duct; 1-8, cylinder barrel positioning holes; 2. a cylinder head flange; 3. a cylinder barrel; 4. a signal plug; 5. a piston; 6. a piston rod; 7. a cylinder bottom; 8. a valve core; 8-1, a spring cavity; 8-2, an unloading groove; 8-3, valve core ring grooves; 8-4, a throttling groove; 8-5, a through oil duct; 8-6, damping holes; 9. a return spring; 10. a valve cover; 11. an oil tank; x, a signal cavity; J. a pressure relief valve port; K. a main valve port; a1, cavity II oil port; a2, cavity II unloading port; b1, a cavity I oil port; b2, a cavity I unloading port; C. a cavity I; D. a cavity II; and Q, a valve core driving cavity.

Detailed Description

The invention will be further explained with reference to the drawings.

Example 1

As shown in figures 1 and 2, a buffer device is arranged at one end of a cavity I, and a buffer valve is integrated in a guide sleeve, so that the buffer of the oil cylinder when a piston at one end of the cavity I approaches the end of the stroke of the oil cylinder can be realized. The hydraulic buffer oil cylinder main body component comprises a guide sleeve, a cylinder head flange, a cylinder barrel, a piston rod and a cylinder bottom, wherein the cylinder head flange and the cylinder bottom are respectively and fixedly connected with two ends of the cylinder barrel to form a whole; the piston rod assembly is characterized by further comprising 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 is fixedly connected with the piston rod, the signal plug is limited between the step surfaces of the piston and the piston rod, the piston is in sliding fit in the cylinder barrel, meanwhile, the piston rod is in sliding fit in a guide hole of the guide sleeve, and further, the guide sleeve is sleeved on the cylinder barrel through cylinder barrel positioning holes 1-8 and is fixedly connected with the cylinder barrel through a cylinder head flange. The piston divides the cylinder chamber into a cavity IID and a cavity IC, the cavity IID is fed with oil or discharged with oil through a cavity IIport A1, the cavity IC is fed with oil or discharged with oil through a cavity I port B1, and the cavity I is discharged with oil or fed with oil from a cavity I unloading port B2. Still be provided with signal chamber X on the uide bushing, the signal chamber can be paired with the signal stopper that corresponds the setting in chamber IC and form sliding fit. The guide sleeve is also provided with valve holes 1-3, annular valve hole oil grooves I, valve hole oil grooves II and valve hole oil grooves III which are formed by expanding outwards along the radial direction of the valve hole are arranged on the valve hole in parallel along the axial direction of the valve hole at intervals, the valve hole oil grooves I are communicated with a cavity II load release port A2 and a cavity II oil port A1, the valve hole oil grooves II are communicated with a cavity I oil port B1, and the valve hole oil grooves III are communicated with a cavity IC through cavity I oil ducts 1-7; the valve core is provided with a valve core ring groove 8-3 which is an annular oil groove with a certain width and depth and formed by expanding inwards along the surface of the valve core, two ends of the valve core ring groove are respectively provided with an unloading groove 8-2 and a throttling groove 8-4, and the unloading groove and the throttling groove are long and narrow oil grooves formed by cutting off materials from the edge of the valve core ring groove along the axial direction on the surface of the valve core, as shown in figure 3; the valve core is also provided with a damping hole 8-6 and a spring cavity 8-1, the damping hole is positioned at one end of the valve core provided with a throttling groove, the spring cavity is arranged at the other end of the valve core, and the valve core ring groove is communicated with one end of the valve core with the spring cavity through a through oil duct 8-5 and is communicated with the other end of the valve core through the damping hole; one end of the valve hole is fixed with a valve cover 10, the other end is connected with a cylinder head flange, the valve core is assembled in the valve hole in a matching way, one end of a return spring 9 is arranged in a spring cavity of the valve core, the other end of the return spring is at low pressure on the cylinder head flange, the valve core and the return spring are restrained between the valve cover and the cylinder head flange, under the normal working state, the valve core is under the thrust action of the return spring, one end of the valve core, which is provided with the damping hole, is low-pressure on the valve cover, at the moment, the valve hole oil groove II and the valve hole oil groove III are normally communicated through the valve core annular groove, the main valve port K is in a normal valve port opening state, the cavity IC can normally feed or discharge oil through the oil duct of the cavity I, the valve hole oil groove III, the main valve port K, the valve hole oil groove II and the oil port B1 of the cavity I, the valve hole oil groove I is in a state of being completely closed by the outer circular surface of the valve core, and a 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 signal oil ducts 1-5, and the signal cavity is communicated with the valve core driving cavity Q through the signal oil ducts.

The action principle of the hydraulic buffer oil cylinder is as follows: as shown in fig. 1, when high-pressure oil enters the cavity iid through the cavity iid port a1, the piston is pushed by the cavity ii high-pressure oil to drive the piston rod assembly to extend outward along the axial direction of the cylinder barrel in the direction indicated by the arrow in fig. 1 under the combined guidance of the inner bore of the cylinder barrel and the guide hole of the guide sleeve, and at the same time, the hydraulic oil in the cavity ic flows back to the oil tank 11 through the cavity i oil passage, the valve hole oil groove iii, the main valve port K, the valve hole oil groove ii and the cavity iid port B1 under the pushing and pressing of the piston; in the process that the piston rod extends outwards, the signal plug moves synchronously along with the piston and gradually approaches to the signal cavity, when the signal plug enters the signal cavity to form sliding fit, as shown in fig. 2 and 4, oil in the signal cavity is separated from oil in the cavity IC and pushed by the signal plug along with the movement of the piston to form control signal pressure oil, and then enters the valve core driving cavity Q through the signal oil passages 1-5, one part of the control signal pressure oil returns through a damping hole 8-6 on the valve core, a through oil duct 8-5, a valve hole oil groove II and a cavity I oil port B1, the rest part pushes the valve core to move against the resistance of the return spring, so as to adjust the opening of the main valve port K and further enable the cavity IC to generate return oil throttling back pressure, the moving speed of the piston is controlled in a mode of oil return throttling back pressure of the cavity I, and the buffering function of the oil cylinder is realized; meanwhile, the valve core moves to open the pressure relief valve port J, so that the unloading groove 8-2 is communicated with the valve hole oil groove I1-1, pressure oil in the cavity IID can be communicated with an oil return tank through the cavity II oil port A1, the cavity II load relief port A2, the valve hole oil groove I, the pressure relief valve port J, the unloading groove 8-2, the valve hole oil groove II and the cavity I oil port B1, the cavity II D is in an unloading state at the moment, and the cavity II D realizes control over the movement speed of the piston through the unloading effect of high-pressure oil, so that the purpose of oil cylinder buffering is achieved through the dual effects of throttling back pressure of the oil return cavity and pressure relief unloading of the high-pressure cavity, and the oil cylinder buffering is energy-saving and. The motion state of the valve core is dynamically controlled by the motion speed of the piston, so that the opening sizes of the main valve port K and the pressure relief valve port J are dynamically adjusted, the pressure of the cylinder cavity IC and the pressure of the cylinder cavity IID are dynamically adjusted and controlled, and the high-quality buffering of the oil cylinder is realized through the dynamic control of the pressure. After the piston stops moving when reaching the stroke end point of the oil cylinder, the buffering is finished, and the valve core returns under the action of the return spring. When the piston needs to return reversely, the cavity IC is communicated with high-pressure oil and the cavity ID is communicated with an oil return tank by operating a main valve (not shown in the figure) of a hydraulic system, so that the reverse motion of the oil cylinder is realized, and the piston rod retracts into the cylinder barrel.

Example 2:

as shown in figure 6, the hydraulic buffer oil cylinder is provided with the buffer device only at one end of the cavity II, and the buffer valve is integrated on the cylinder bottom, so that the buffer of the oil cylinder when the piston at one end of the cavity II approaches the stroke end of the oil cylinder can be realized. The main differences compared to example 1 are: the valve hole and the signal cavity are arranged on the cylinder bottom, and the signal plug is of a cylindrical structure and is arranged at the central position of the bottom of the piston rod, the action principle of the signal plug is similar to that of embodiment 1, and the function principle is not repeated.

Example 3:

as shown in fig. 7, the two ends of the hydraulic buffer cylinder are provided with the buffer devices, so that the buffer of the cylinder when the piston at any end approaches the end of the stroke of the cylinder can be realized. The present embodiment is a composite structure of embodiments 1 and 2, and can realize a bidirectional buffer function of the oil cylinder. When the piston approaches the stroke end of one end of the oil cylinder in the working process of the oil cylinder, only the buffer device arranged at the end is activated to play a buffer function, the action principle is similar to that of the previous device, and the operation is not repeated.

Example 4:

the arrangement form of the unloading groove and the throttling groove of the valve core can be changed in various ways, and the adjustment performance of the notch can be changed by changing the depth, width, form, position, cross-sectional shape and the like of the groove according to requirements, so that more excellent speed regulation characteristic is obtained, and the buffering performance of the oil cylinder is improved.

The unloading groove and the throttling groove shown in fig. 3 and 4 are of shallow and narrow long and narrow structures, wherein the cross section of the throttling groove is a variable cross section, the groove width of the throttling groove gradually narrows from the width of the valve core ring groove 8-3 to the arc sealing head from the outside, the bottom surface of the unloading groove is a step surface with different depths, and the groove depth of the arc sealing head end is shallow, so that unloading stability is improved, the variable cross section of the throttling groove is realized from the aspects of width and depth by the arrangement of the unloading groove, and the buffering performance of the oil cylinder is improved; the throttling groove is basically of a structure with equal width and equal depth, so that the processing is simple;

the unloading groove and the throttling groove shown in fig. 5 are radial small round holes communicated with the through oil passage 8-5, and the structure is simplified.

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

While the above is a description of the structure of embodiments 1-4, it is obvious that many more embodiments can be varied with reference to the guidance of the schematic diagrams 1-8 and the description of the above embodiments 1-4, and will not be described in detail here.

It should be noted that the above are only preferred embodiments of the present invention, but the scope of the present invention is not limited thereto. Obviously, various changes can be made according to actual needs, such as: the structure of the valve core and the valve hole is changed, the arrangement mode of the signal cavity and the signal plug is changed, the oil port and the oil channel are changed (position, direction, shape, form and the like), the shape, the position and the number of the oil groove or the oil cavity are changed, the structure of the oil cylinder is changed, and the like; the damping spring piece can be arranged in various forms, for example, the damping spring piece can be assembled in a compression mode in the elastic cavity, but can also be arranged at the other end of the slide valve in a stretching mode, and the same effect is achieved. Any person skilled in the art should also be able to substitute or change the principle diagrams, the embodiments and the inventive concept of the present invention within the technical scope of the present disclosure.

Claims

1. The utility model provides a hydraulic cushion cylinder, including uide bushing (1), cylinder end flange (2), cylinder (3), piston (5), piston rod (6), cylinder end (7), both ends formation cylinder body in cylinder (3) are fixed respectively in cylinder end flange (2) and cylinder end (7), uide bushing (1) is through guiding hole (1-6) sliding fit on piston rod (6), piston (5) fixed connection forms piston rod subassembly and sliding fit in cylinder (3) in the one end of piston rod (6), uide bushing (1) and cylinder end flange (2) fixed connection, cylinder (3) are by the centre gripping between uide bushing (1) and cylinder end (7), piston (5) separate the cylinder body inner chamber for two hydro-cylinder chambers of chamber I (C) and chamber II (D), its characterized in that: at least one end of the cylinder body is provided with a buffer device, the buffer device comprises 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 part of the cylinder body, the signal plug (4) is correspondingly arranged on the piston rod assembly, and three annular oil grooves which are radially expanded outwards from the surface of the valve hole (1-3) are sequentially arranged in parallel at certain intervals along the axial direction in the valve hole (1-3): the buffer device comprises a valve hole oil groove I (1-1), a valve hole oil groove II (1-2) and a valve hole oil groove III (1-4), wherein the valve hole oil groove III (1-4) is communicated with an oil cylinder cavity at the corresponding end of the buffer device, the valve hole oil groove I (1-1) is communicated with the oil cylinder cavity at the other end of the cylinder body, and an oil inlet and an oil outlet of the oil cylinder cavity are arranged on the corresponding valve hole oil groove II (1-2); a valve core ring groove (8-3) is formed in the middle of the valve core (8), an unloading groove (8-2) and a throttling groove (8-4) are formed in the two sides of the valve core ring groove (8-3) respectively, and the unloading groove (8-2) and the throttling groove (8-4) are communicated with the valve core ring groove (8-3); a damping hole (8-6) and a spring cavity (8-1) are arranged at the center of the valve core (8), the damping hole (8-6) is positioned at one end of the valve core (8) provided with a throttling groove (8-4), the spring cavity (8-1) is arranged at the other end of the valve core (8), and the valve core ring groove (8-3) is communicated with the end of the valve core spring cavity (8-1) through a through oil duct (8-5) and is communicated with a valve core driving cavity (Q) at the other end of the valve core (8) through the damping hole (8-6); the valve core (8) is assembled in the valve hole (1-3) in a matching mode, the valve core driving cavity (Q) and the valve core spring cavity (8-1) are located at two ends of the valve core (8) respectively, one end, provided with the damping hole (8-6), of the valve core (8) faces the valve core driving cavity (Q), one end of the return spring (9) is installed in the spring cavity (8-1) of the valve core (8), the other end of the return spring abuts against a part at the bottom of the valve hole (1-3), the valve core (8) and the return spring (9) are restrained in the valve hole (1-3), the signal cavity (X) is correspondingly arranged on a part at the end of the cylinder body and is communicated with the valve core driving cavity (Q) of the valve hole (1-3) through the signal oil duct (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) along with the movement of the piston (5), so that the signal plug can be in sliding fit with or separated from the corresponding signal cavity (X).

2. A hydraulic cushion cylinder as claimed in claim 1, wherein the cushion device is provided at the end of the chamber i (C), and the valve hole (1-3) and the signal chamber (X) are provided on the guide sleeve (1), so as to cushion the cylinder at the end of the chamber i (C).

3. A hydraulic cushion cylinder as claimed in claim 1, wherein the cushion device is provided at the end of chamber ii (D), and the valve hole (1-3) and the signal chamber (X) are provided on the cylinder bottom (7), so as to cushion the cylinder at the end of chamber ii (D).

4. The hydraulic buffer oil cylinder as claimed in claim 1, wherein the two ends of the oil cylinder are respectively provided with a buffer device, the valve hole (1-3) and the signal cavity (X) of the buffer device at the end of the cavity I (C) are arranged on the guide sleeve (1), and the valve hole (1-3) and the signal cavity (X) of the buffer device at the end of the cavity II (D) are arranged on the cylinder bottom (7), so that the oil cylinder can buffer at the end of the cavity I (C) and the end of the cavity II (D) respectively.

5. A hydraulic cushion cylinder according to any one of claims 1-4, characterized in that the relief groove (8-2) and/or the throttle groove (8-4) is of shallow and narrow elongate configuration.

6. A hydraulic cushion cylinder according to any one of claims 1-4, characterized in that the relief groove (8-2) and/or the throttle groove (8-4) is/are a slope inclined at an angle along the surface of the spool (8), the slope being inclined from the outside in the direction of the spool ring groove (8-3).

7. A hydraulic cushion cylinder according to any one of claims 1-4, characterized in that the relief groove (8-2) and/or the throttle groove (8-4) is a radial bore communicating with the through-going oil channel (8-5).

8. A hydraulic cushion cylinder according to claim 5, characterized in that the relief groove (8-2) and/or the throttle groove (8-4) is of a shallow and narrow elongated structure with a cross section of variable cross section, the cross section area of which gradually decreases from the valve core annular groove (8-3) to the outside.

9. The hydraulic cushion cylinder as claimed in claim 5, wherein the relief groove (8-2) and/or the throttle groove (8-4) has a groove width in the range of 1-12mm and a groove depth in the range of 0.1-4 mm.

10. The hydraulic cushion cylinder according to any one of claims 1 to 4, wherein the range of the valve core drive ratio is 0.5 to 1.5, and the diameter range of the damping hole (8 to 6) is 0.8 to 3 mm; the rigidity range of the return spring (9) is 2-10N/mm.