CN206530567U - Hydraulic cylinder - Google Patents

Abstract

The utility model is related to a kind of hydraulic cylinder, including cylinder bottom (1), cylinder barrel (2), piston rod (3) and hydraulic control one-way valve (4), cylinder barrel (2) one end is connected with cylinder bottom (1), piston rod (3) is telescopically inserted in cylinder barrel (2), hydraulic control one-way valve (4) is arranged on cylinder bottom (1), piston rod (3) is provided with one during piston rod (3) is retracted into cylinder barrel (2), hydraulic control one-way valve (4) can be opened, and after piston rod (3) is fully retracted, it can remain that hydraulic control one-way valve (4) is in open mode, so that the unlocking mechanism that outside oil piping system is turned on cylinder barrel (2) inner chamber.The utility model advantage is：Can not only piston rod be easy to be fully retracted, so that vehicle cab can be put down completely, security is good, and when vehicle cab is produced in vehicle travel process and pitched, the impulsive force to hydraulic cylinder can be greatly reduced, so as to can guarantee that the quality of hydraulic cylinder, hydraulic cylinder is prevented effectively from and is damaged.

Description

Hydraulic cylinder

Technical field

The utility model is related to a kind of fluid pressure actuator, specifically a kind of hydraulic cylinder.

Background technology

Hydraulic cylinder is that hydraulic energy is changed into mechanical energy, straight reciprocating motion is done or the hydraulic pressure of oscillating motion performs member Part.Its simple in construction, reliable operation, is realized with it during reciprocating motion, can remove deceleration device from, and without drive gap, Stable movement, therefore be used widely in various mechanical hydraulic systems.At present, the vehicle such as existing engineering truck, lorry Driving cabin bottom can all be provided with hydraulic cylinder, when needing to open the vehicle cabs such as engineering truck, lorry, and hydraulic cylinder just can be by Driving cabin side jack-up is come and supported.Existing hydraulic cylinder generally comprises cylinder barrel, cylinder bottom and piston rod, and the oil circuit of hydraulic cylinder Also hydraulic control one-way valve can be all provided with passage, the setting of hydraulic control one-way valve mainly plays two, one is when external oil pipe is quick-fried Split, the burst implementations such as gear pump is burst when, hydraulic control one-way valve can be closed automatically, and now the fluid in Barrel of Hydraulic Cylinders can stop Flow outwardly, stop in hydraulic cylinder, so as to avoid driving cabin dramatic decrease；The second is realizing the auto-lock function of hydraulic cylinder, i.e., After piston rod stretching, even if outside oil piping system fuel cut-off, hydraulic control one-way valve can also prevent the fluid in Barrel of Hydraulic Cylinders Flow outwardly, so as to reach the purpose that piston rod is locked in stretching state, realize in hydraulic cylinder and stop.But the hydraulic pressure of said structure Also there is a weak point in actual application in cylinder：The piston rod of above-mentioned this hydraulic cylinder is to be fully retracted, not only Need outside oil piping system to carry out oil extraction, and also need to by vehicle cab to its lower pressure cooperation, but work as Vehicle cab close to put down completely set back when, now hydraulic cylinder is close to horizontality, and the lower pressure of vehicle cab is applied The axial force being added on hydraulic cylinder piston rod is very small, so that being easily caused the piston rod of hydraulic cylinder can not be fully retracted, And then cause vehicle cab to put down completely, there is potential safety hazard；And when vehicle is travelled, outside oil piping system closes logical Often it is closed, and once outside oil piping system is closed, hydraulic control one-way valve just prevents the fluid in Barrel of Hydraulic Cylinders outside Outflow, now when vehicle cab is produced in vehicle travel process to pitch, will continually apply to hydraulic cylinder and make Firmly, and because the fluid in Barrel of Hydraulic Cylinders can not be discharged, therefore piston rod can not be retracted again, and such hydraulic cylinder is frequent Impact under be easy for damage.

Utility model content

The technical problems to be solved in the utility model is to provide one kind and is not only able to be easy to piston rod to be fully retracted, so that Vehicle cab is put down completely, security is good, and run above and below vehicle cab is produced in vehicle travel process When winnowing with a dustpan, the impulsive force to hydraulic cylinder can be greatly reduced, so as to ensure the quality of hydraulic cylinder, be prevented effectively from hydraulic cylinder by The hydraulic cylinder of damage.

In order to solve the above technical problems, the utility model provides a kind of hydraulic cylinder of following structure：Including cylinder bottom, cylinder Cylinder, piston rod and hydraulic control one-way valve, cylinder barrel one end are connected with cylinder bottom, and piston rod is telescopically inserted in cylinder barrel, wherein, hydraulic control Check valve is arranged on cylinder bottom, and piston rod is provided with one during piston rod is retracted into cylinder barrel, can be by fluid-control one-way Valve is opened, and after piston rod is fully retracted, can remain that hydraulic control one-way valve is in open mode, so that outside oil The unlocking mechanism that road system is turned on inner cavity of cylinder.

Hydraulic cylinder described in the utility model, wherein, cylinder bottom, which is provided with, to be used to connect hydraulic control one-way valve and the axial direction of cylinder barrel leads to Road, unlocking mechanism can extend into axial passage including one, and during piston rod is retracted into cylinder barrel, one end can Through axial passage and the second push rod of hydraulic control one-way valve is opened, the second push rod other end is connected with piston rod.

Hydraulic cylinder described in the utility model, wherein, unlocking mechanism also includes second spring, and piston rod one end is provided with axially First annular step is provided with the middle part of slot, the second push rod, first annular step maximum outside diameter is more than the maximum inner diameter of axial passage, Second push rod one end is located in axial socket, and the second push rod in axial socket is provided with the second ring-shaped step, the second ring The maximum outside diameter of shape step is more than the maximum outside diameter of first annular step, and second spring is located in axial socket, and is enclosed on second On push rod, while withstanding between the second ring-shaped step and axial socket bottom, the internal perisporium at axial socket opening is provided with ring Shape boss, annular boss is slidably connected with first annular step.

Hydraulic cylinder described in the utility model, wherein, annular boss inwall is provided with steel-backed bearing, steel-backed bearing and first Ring-shaped step is slidably connected.

Hydraulic cylinder described in the utility model, wherein, the second ring-shaped step is made up of at least one nut, and nut thread connects It is connected on second push rod of first annular step one end, second spring is withstood between the second collar nut and axial socket bottom.

Hydraulic cylinder described in the utility model, wherein, annular boss is provided with least one through hole, and through hole one end passes through cylinder Tube inner chamber is communicated with axial passage, and the through hole other end is communicated with axial socket.

Hydraulic cylinder described in the utility model, wherein, hydraulic cylinder is multistage hydraulic cylinder, and axial socket is arranged on afterbody On piston rod, other grades of piston rod one end in addition to afterbody piston rod are equipped with the perforation passed through for the second push rod.

Hydraulic cylinder described in the utility model, wherein, hydraulic control one-way valve includes valve seat, valve element, control piston, the first chamber Room, second chamber, the first logical hydraulic fluid port and the second logical hydraulic fluid port, valve seat, first chamber, second chamber, the first logical hydraulic fluid port and second are logical Hydraulic fluid port is arranged on cylinder bottom, and valve seat be located at first chamber is communicated between first chamber and second chamber, and on valve seat With the connecting hole of second chamber, valve element is slidably connected in second chamber, and valve element one end can be sealed with valve seat one end to be coordinated, control Piston processed is slidably connected in first chamber, and axial passage one end is communicated with second chamber, is retracted in piston rod into cylinder barrel Cheng Zhong, it is next that unlocking mechanism can be such that valve element is separated from from valve seat, and after piston rod is fully retracted, unlocking mechanism can make Valve element remains disengaged position with valve seat, so that hydraulic control one-way valve is in open mode all the time, control piston one end is provided with A piece one end can pass through connecting hole and push up the first push rod of valve opening core, the first logical hydraulic fluid port and first at the control piston other end Chamber, the second logical hydraulic fluid port is connected with connecting hole.

Hydraulic cylinder described in the utility model, wherein, valve element includes valve block, spring base and the first spring, and spring base is slided It is connected in second chamber, valve block is connected to spring base end, the first spring housing withstands on spring base and cylinder on spring base Between bottom, during piston rod is retracted into cylinder barrel, it is next that unlocking mechanism can be such that valve block is separated from from valve seat, and in work After stopper rod is fully retracted, unlocking mechanism can make valve block remain disengaged position with valve seat, so that hydraulic control one-way valve is all the time In open mode.

Hydraulic cylinder described in the utility model, wherein, spring base one end is provided with groove, and valve block is spherical in shape, and majority It is embedded in groove.

After said structure, the utility model has advantages below：The utility model hydraulic cylinder is in the work that will extend , also can be by unlocking mechanism by fluid-control one-way even if outside oil piping system is stopped during stopper rod is retracted into cylinder barrel Valve is opened, and outside oil piping system is constantly in conducting state with inner cavity of cylinder, so when vehicle cab is run in vehicle When generation pitches in journey, vehicle cab can produce impulsive force, percussive pressure of the hydraulic cylinder in vehicle cab to hydraulic cylinder Hydraulic oil in cylinder barrel can be just discharged to the outside oil piping system by power, so that piston rod can be fully retracted, and then make vehicle Driving cabin can be put down completely, substantially increase the security of vehicle；And after vehicle cab is put down completely, In vehicle travel process, not only the vertical tremor amplitude of vehicle cab can greatly reduce, and unlocking mechanism is complete in piston rod After full reduced time, can still remain that hydraulic control one-way valve is in open mode, even if therefore when vehicle jolts severity, vehicle is driven The vertical tremor amplitude for sailing cabin becomes big, and when the pulling force or pressure that make vehicle cab larger to hydraulic cylinder generation, piston rod also can Stretch out or retract with the vertical tremor of vehicle cab, thus substantially reduce impact of the vehicle cab to hydraulic cylinder Power, so as to ensure that the quality of hydraulic cylinder, effectively prevent hydraulic cylinder and is damaged.

Unlocking mechanism in the utility model hydraulic cylinder is not only simple in construction, and can also be easy to the utility model hydraulic cylinder Integration Design, good reliability.

Because the utility model hydraulic cylinder unlocking mechanism also includes second spring, piston rod one end is provided with axial socket, the First annular step is provided with the middle part of two push rods, first annular step maximum outside diameter is more than the maximum inner diameter of axial passage, the second top Bar one end is located in axial socket, and the second push rod in axial socket is provided with the second ring-shaped step, the second ring-shaped step Maximum outside diameter be more than the maximum outside diameter of first annular step, second spring is located in axial socket, and is enclosed on the second push rod, Withstand on simultaneously between the second ring-shaped step and axial socket bottom, the internal perisporium at axial socket opening is provided with annular boss, Annular boss is slidably connected with first annular step, therefore so that the length of the second push rod can be greatly increased, so in piston During in bar retraction cylinder barrel, the second push rod can be just entered in axial passage earlier, so in vehicle cab no longer Continue to decline, when user closes outside oil piping system, it is ensured that the second push rod has been able to open hydraulic control one-way valve；And work as piston rod After being fully retracted, the overall intrinsic energy again of the second push rod is in axial passage and axial socket, so that the second push rod is not required to take this The extra length space of utility model hydraulic cylinder, and then it is easy to control the length of the utility model hydraulic cylinder.

The setting of steel-backed bearing can effectively ensure that the second push rod in motion process with axial passage and axial socket it Between axiality, but also effectively increase the abrasion resistance between the second push rod and piston rod.

Second ring-shaped step is made up of at least one nut, and so by user, just energy adjusting nut is upper in the second push rod Put and state the pretightning force of second spring to adjust, so as to significantly facilitate the design and adjustment of unlocking mechanism.

The effect for the through hole being arranged on annular boss is can to make axial socket faster oil-feed or oil extraction, so as to effectively carry The operating efficiency of high the utility model hydraulic cylinder.

Hydraulic cylinder is multistage hydraulic cylinder, can thus greatly increase the stroke of the utility model hydraulic cylinder.

Hydraulic control one-way valve in the utility model hydraulic cylinder is not only simple in construction, and good reliability, so that not only significantly The Integration Design of the utility model hydraulic cylinder is facilitated, and the design of tripper can also be easy to.

Valve element in the utility model hydraulic cylinder is not only simple in construction, and good reliability, so as to not only greatly facilitate The Integration Design of the utility model hydraulic cylinder, and the design of tripper can also be easy to.

The attachment structure of spring base and valve block is not only simple in construction, and good reliability, so as to not only greatly facilitate this The Integration Design of utility model hydraulic cylinder, and the design of tripper can also be easy to；In addition, the spheroidal structure energy of valve block Enough it is easy to the second push rod to be opened valve opening core top is pushed up, but also second push rod one end can be avoided stuck situation hair occur with valve element It is raw.

Brief description of the drawings

Fig. 1 is the cross section structure diagram when piston rod of the utility model hydraulic cylinder is fully retracted；

Fig. 2 is the cross section structure diagram of the line A-A along along Fig. 1.

Embodiment

The utility model hydraulic cylinder is described in further detail with reference to the accompanying drawings and detailed description.

As depicted in figs. 1 and 2, the utility model hydraulic cylinder includes cylinder bottom 1, cylinder barrel 2, piston rod 3 and hydraulic control one-way valve 4, the one end of cylinder barrel 2 is connected with cylinder bottom 1, and piston rod 3 is telescopically inserted in cylinder barrel 2, is set between the other end of cylinder barrel 2 and piston rod 3 There is first sealing device 5, hydraulic control one-way valve 4 is arranged on cylinder bottom 1, piston rod 3 is provided with one when piston rod 3 is into cylinder barrel 2 During retraction, hydraulic control one-way valve 4 can be opened, and after piston rod 3 is fully retracted, fluid-control one-way can be remained Valve 4 is in open mode, so that the unlocking mechanism that outside oil piping system is turned on the inner chamber of cylinder barrel 2, cylinder bottom 1 is closed provided with first Second joint bearing 7 is provided with bearings 6, piston rod 3, cylinder bottom 1 is provided with the axial direction for being used for connecting hydraulic control one-way valve 4 and cylinder barrel 2 Passage 8, unlocking mechanism can extend into axial passage 8 including one, and during piston rod 3 is retracted into cylinder barrel 2, one End can pass through axial passage 8 and open the second push rod 9 of hydraulic control one-way valve 4, and the other end of the second push rod 9 is connected with piston rod 3, Unlocking mechanism also includes second spring 10, and the one end of piston rod 3 is provided with axial socket 11, and the middle part of the second push rod 9 is provided with first annular Step 12, the maximum outside diameter of first annular step 12 is more than the maximum inner diameter of axial passage 8, and the one end of the second push rod 9 is located at axially In slot 11, and the second push rod 9 being located in axial socket 11 is provided with the second ring-shaped step 13, the maximum of the second ring-shaped step 13 External diameter is more than the maximum outside diameter of first annular step 12, and in the present embodiment, first annular step 12 and axial passage 8 are circle Cylindricality, therefore the maximum outside diameter of first annular step 12 and the maximum inner diameter of axial passage 8 refer to their own diameter； Second spring 10 is located in axial socket 11, and is enclosed on the second push rod 9, while withstanding on the second ring-shaped step 13 and axial socket Between 11 bottoms, the internal perisporium at the opening of axial socket 11 is provided with annular boss 14, annular boss 14 and first annular step 12 are slidably connected, and the inwall of annular boss 14 is provided with steel-backed bearing 15, and steel-backed bearing 15 is slidably connected with first annular step 12, Second ring-shaped step 13 is made up of at least one nut 16, and nut 16 is threaded in second top of the one end of first annular step 12 On bar 9, second spring 10 is withstood between the second collar nut 16 and the bottom of axial socket 11, in the present embodiment, and nut 16 is Two, two nuts 16 are closely packed together, and so can be achieved with double nut pretension, it is to avoid nut 16 is during hydraulic cylinder use Displacement is produced with respect to the second push rod 9, a packing ring 17 can be set between nut 16 and second spring 10, annular boss 14 is provided with At least one through hole 18, one end of through hole 18 is communicated by the inner chamber of cylinder barrel 2 with axial passage 8, the other end of through hole 18 and axial socket 11 communicate, and hydraulic cylinder is that the hydraulic cylinder in multistage hydraulic cylinder, the present embodiment is level Four hydraulic cylinder, and axial socket 11 is arranged on finally On first stage piston bar 3, other grades of one end of piston rod 3 in addition to afterbody piston rod 3 are equipped with what is passed through for the second push rod 9 The second sealing device 20 is equipped between perforation 19, adjacent two-stage piston rod 3, first sealing device 5 is arranged on cylinder barrel 2 and first Between level piston rod 3, the concrete structure of the sealing device 20 of first sealing device 5 and second, other specific knots of piston rod at different levels 3 Fit structure between the mutual fit structure of structure, piston rod at different levels 3, cylinder barrel 2 and first order piston rod 3 is existing routine Technology, therefore do not repeat herein, hydraulic control one-way valve 4 includes valve seat 21, valve element 22, control piston 23, first chamber 24, second chamber 25th, the first logical hydraulic fluid port 26 and second leads to hydraulic fluid port 27, and valve seat 21, first chamber 24, second chamber 25, first lead to hydraulic fluid port 26 and second Logical hydraulic fluid port 27 is radially arranged on cylinder bottom 1, and valve seat 21 is located between first chamber 24 and second chamber 25, and on valve seat 21 The connecting hole 28 of first chamber 24 and second chamber 25 is communicated with, valve element 22 is slidably connected in second chamber 25, valve element 22 One end can be sealed with the one end of valve seat 21 to be coordinated, and control piston 23 is slidably connected in first chamber 24, one end of axial passage 8 and the Two chambers 25 are communicated, during piston rod 3 is retracted into cylinder barrel 2, and unlocking mechanism can be such that valve element 22 departs from from valve seat 21 Come, and after piston rod 3 is fully retracted, unlocking mechanism can make valve element 22 remain disengaged position with valve seat 21, from And hydraulic control one-way valve 4 is in open mode all the time, control piston 23 one end can be through connecting hole 28 simultaneously provided with an one end The first push rod 29 of valve opening core 22 is pushed up, the first logical hydraulic fluid port 26 is connected with the first chamber 24 at the control other end of piston 23, second Logical hydraulic fluid port 27 is connected with connecting hole 28, and control piston 23 perisporium is provided with sealing ring 30, and the setting of sealing ring 30 can avoid the One logical hydraulic fluid port 26 is connected with the second logical hydraulic fluid port 27 by first chamber 24, and valve element 22 includes valve block 31, the bullet of spring base 32 and first Spring 33, spring base 32 is slidably connected in second chamber 25, and valve block 31 is connected to the end of spring base 32, and the first spring 33 is enclosed on On spring base 32, and withstand between spring base 32 and cylinder bottom 1, in the present embodiment, connected on the cylinder bottom 1 of the one end of second chamber 25 There is plug 35, the one end of the first spring 33 is withstood on plug 35, and during piston rod 3 is retracted into cylinder barrel 2, unlocking mechanism can Make valve block 31 be separated from from valve seat 21 to come, and after piston rod 3 is fully retracted, unlocking mechanism can make valve block 31 and valve seat 21 remain disengaged position, so that hydraulic control one-way valve 4 is in open mode all the time, the one end of spring base 32 is provided with groove 34, Valve block 31 is spherical in shape, and majority is embedded in groove 34, and one end that the second push rod 9 is used to push up valve opening core 22 may be designed to cone Shape, taper not only has guide effect, so as to be easy to the one end of the second push rod 9 to stretch into axial passage 8 and will push up valve opening core 22 Open on top, it is to avoid stuck situation is produced between the one end of the second push rod 9 and axial passage 8 or valve element 22.

The operation principle of the utility model hydraulic cylinder is：In 3 fully retracted state of piston rod, the one end of the second push rod 9 exists The valve block 31 of spheroidal push up through axial passage 8 and from valve seat 21 opened under the elastic force effect of second spring 10, make outside oily Road system is turned on the inner chamber of cylinder barrel 2；When needing that piston rod 3 is protruding, the second logical hydraulic fluid port 27 passes through outside oil piping system Oil-feed, with the stretching of piston rod 3, the second push rod 9, with being axially moved, leaves the one end of the second push rod 9 by piston rod 3 Valve block 31, is then lifted off axial passage 8, now continues in the second logical hydraulic fluid port 27 under oil-feed, valve block 31 and control piston 23 quilt Push away and lift off a seat 21, hydraulic control one-way valve 4 is in open mode all the time；When outside oil piping system is stopped, i.e., outside oil circuit System stops to during the second logical 27 oiling of hydraulic fluid port, and in the first spring 33 under elastic force effect, valve block 31 is withstood on valve seat 21, hydraulic control Check valve 4 is closed, and now hydraulic cylinder is in the lock state；When needing to retract in piston rod 3, the first logical hydraulic fluid port 26 passes through outside Oil piping system oil-feed, now controls piston 23 to move and be pressed on valve seat 21 towards the direction of valve seat 21 after being pressurized, the first push rod 29 Valve opening block 31 is pushed up, now hydraulic control one-way valve 4 is opened, and hydraulic cylinder is under the suppressing action of vehicle cab, and piston rod 3 gradually contracts Return, the hydraulic oil in cylinder barrel 2 is gradually discharged, during piston rod 3 is gradually retracted, and the one end of the second push rod 9 gradually extend into axle Into passage 8 and eventually pass through axial passage 8 and enter in second chamber 25, when vehicle cab can not make piston rod 3 contract again Hui Shi, closes outside oil piping system and is stopped, i.e., outside oil piping system stops leading to the oiling of hydraulic fluid port 26 to first, now valve block 31 Moved in the first spring 33 under elastic force effect to the direction of valve seat 21, but under the stop of the one end of the second push rod 9, valve block 31 It can withstand on the second push rod 9 and can not withstand on valve seat 21, so allow for hydraulic control one-way valve 4 and be in open mode all the time；When Vehicle cab is produced in vehicle travel process when jolting, and vehicle cab will produce impulsive force, hydraulic cylinder to hydraulic cylinder Just the hydraulic oil in cylinder barrel 2 can be discharged to the outside oil piping system in the surge of vehicle cab, so that the energy of piston rod 3 Enough it is fully retracted, and then vehicle cab is put down completely；In addition, when the vertical tremor amplitude of vehicle cab becomes Greatly, when the vehicle cab is produced larger pulling force or pressure to hydraulic cylinder, piston rod 3 also can be with vehicle cab above and below Shake and stretch out or retract, impulsive force of the vehicle cab to hydraulic cylinder is thus substantially reduced, so as to ensure that hydraulic cylinder Quality, effectively prevent hydraulic cylinder be damaged.

Embodiment above is only that preferred embodiment of the present utility model is described, not to the utility model Scope be defined, on the premise of the utility model design spirit is not departed from, those of ordinary skill in the art are to this practicality Various modifications and improvement that new technical scheme is made, all should fall into the protection domain of the utility model claims determination It is interior.

Claims (10)

1. a kind of hydraulic cylinder, including cylinder bottom (1), cylinder barrel (2), piston rod (3) and hydraulic control one-way valve (4), the cylinder barrel (2) one End is connected with cylinder bottom (1), and the piston rod (3) is telescopically inserted in cylinder barrel (2), it is characterised in that：The hydraulic control one-way valve (4) it is arranged on cylinder bottom (1), the piston rod (3) works as piston rod (3) into cylinder barrel (2) during retraction provided with one, energy It is enough to open hydraulic control one-way valve (4), and after piston rod (3) is fully retracted, can remain that hydraulic control one-way valve (4) is in Open mode, so that the unlocking mechanism that outside oil piping system is turned on cylinder barrel (2) inner chamber.

2. hydraulic cylinder according to claim 1, it is characterised in that：The cylinder bottom (1), which is provided with, to be used to connect hydraulic control one-way valve (4) and cylinder barrel (2) axial passage (8), the unlocking mechanism can extend into axial passage (8), and in work including one Stopper rod (3) is to during retracting in cylinder barrel (2), and one end through axial passage (8) and can open the second of hydraulic control one-way valve (4) Push rod (9), the second push rod (9) other end is connected with piston rod (3).

3. hydraulic cylinder according to claim 2, it is characterised in that：The unlocking mechanism also includes second spring (10), institute Piston rod (3) one end is stated provided with axial socket (11), the second push rod (9) middle part is provided with first annular step (12), described The maximum outside diameter of first annular step (12) is more than the maximum inner diameter of axial passage (8), and described second push rod (9) one end is located at axle In to slot (11), and the second push rod (9) being located in axial socket (11) is provided with the second ring-shaped step (13), second ring The maximum outside diameter of shape step (13) is more than the maximum outside diameter of first annular step (12), and the second spring (10), which is located at, axially inserts In groove (11), and it is enclosed on the second push rod (9), while withstand between the second ring-shaped step (13) and axial socket (11) bottom, Internal perisporium at axial socket (11) opening is provided with annular boss (14), the annular boss (14) with first annular Rank (12) is slidably connected.

4. hydraulic cylinder according to claim 3, it is characterised in that：Annular boss (14) inwall is provided with steel-backed bearing (15), the steel-backed bearing (15) is slidably connected with first annular step (12).

5. hydraulic cylinder according to claim 3, it is characterised in that：Second ring-shaped step (13) is by least one nut (16) constitute, the nut (16) is threaded on second push rod (9) of first annular step (12) one end, second bullet Spring (10) is withstood between the second collar nut (16) and axial socket (11) bottom.

6. hydraulic cylinder according to claim 3, it is characterised in that：The annular boss (14) is provided with least one through hole (18), described through hole (18) one end is communicated by cylinder barrel (2) inner chamber with axial passage (8), through hole (18) other end and axle Communicated to slot (11).

7. the hydraulic cylinder according to claim 3 or 4 or 5 or 6, it is characterised in that：The hydraulic cylinder is multistage hydraulic cylinder, institute State axial socket (11) to be arranged on afterbody piston rod (3), other grades of piston rod (3) one end are equipped with for the second push rod (9) perforation (19) passed through.

8. the hydraulic cylinder according to claim 2~6 any one, it is characterised in that：The hydraulic control one-way valve (4) includes valve Seat (21), valve element (22), control piston (23), first chamber (24), second chamber (25), the first logical hydraulic fluid port (26) and second are logical Hydraulic fluid port (27), the valve seat (21), first chamber (24), second chamber (25), the first logical hydraulic fluid port (26) and the second logical hydraulic fluid port (27) it is arranged on cylinder bottom (1), and the valve seat (21) is located between first chamber (24) and second chamber (25), and it is described The connecting hole (28) of first chamber (24) and second chamber (25) is communicated with valve seat (21), the valve element (22) is slidably connected In second chamber (25), described valve element (22) one end can be sealed with valve seat (21) one end to be coordinated, and the control piston (23) is sliding Dynamic to be connected in first chamber (24), described axial passage (8) one end is communicated with second chamber (25), in piston rod (3) to cylinder During being retracted in cylinder (2), it is next that unlocking mechanism can be such that valve element (22) is separated from from valve seat (21), and in piston rod (3) After being fully retracted, unlocking mechanism can make valve element (22) remain disengaged position with valve seat (21), so that hydraulic control one-way valve (4) open mode is in all the time, and described control piston (23) one end can pass through connecting hole (28) and push up and open provided with an one end The first push rod (29) of valve element (22), the described first logical hydraulic fluid port (26) and the first chamber (24) at control piston (23) other end Connection, the described second logical hydraulic fluid port (27) is connected with connecting hole (28).

9. hydraulic cylinder according to claim 8, it is characterised in that：The valve element (22) includes valve block (31), spring base (32) and the first spring (33), the spring base (32) is slidably connected in second chamber (25), and the valve block (31) is connected to Spring base (32) end, first spring (33) is enclosed on spring base (32), and withstand on spring base (32) and cylinder bottom (1) it Between, during piston rod (3) is retracted into cylinder barrel (2), unlocking mechanism can be such that valve block (31) is separated from from valve seat (21) Come, and after piston rod (3) is fully retracted, unlocking mechanism can make valve block (31) remain disengaging shape with valve seat (21) State, so that hydraulic control one-way valve (4) is in open mode all the time.

10. hydraulic cylinder according to claim 9, it is characterised in that：Described spring base (32) one end is provided with groove (34), institute State valve block (31) spherical in shape, and majority is embedded in groove (34).