CN218598517U - Telescopic cylinder, hydraulic system and operation machine - Google Patents

Abstract

The utility model relates to the technical field of operating machinery, and provides a telescopic cylinder, a hydraulic system and operating machinery, which comprises a cylinder body, a piston rod and a limiting part for adjusting the maximum moving stroke of the piston rod, wherein the cylinder body is provided with a first port, a second port and a third port communicated with an external control source, a rodless cavity is communicated with the first port, and a rod cavity is respectively communicated with the second port and the third port; the limiting piece is arranged in the cylinder body in a sliding mode and can slide relative to the piston rod, and the piston can abut against the limiting piece; the limiting piece is positioned between the second through hole and the third through hole and is respectively in sealing fit with the rod part of the piston rod and the cylinder body; the limiting piece is provided with a first notch opposite to the second opening and a second notch opposite to the third opening. The position of the limiting piece can be adjusted by controlling the third through hole to enter or exit oil or gas so as to adjust the maximum moving stroke of the piston rod.

Description

Telescopic cylinder, hydraulic system and operating machine

Technical Field

The utility model relates to an operation machinery technical field especially relates to a telescoping cylinder, hydraulic system and operation machinery.

Background

When the existing partial mechanical structure is at the extreme position, the extending amount of the oil cylinder needs to be limited for preventing danger, and when the existing partial mechanical structure is at a normal position or a normal position, the limiting requirement on the oil cylinder needs to be removed so as to meet the normal working requirement of the mechanical structure.

At the present stage, the stroke limit of the oil cylinder is mainly regulated and controlled by two methods, one is as follows: through the regulation and control of a sensor, for example, a sensor for detecting the stroke of a piston rod is arranged in an oil cylinder, when the sensor detects that the stroke of the piston rod is a preset stroke, the piston rod can be controlled to stop moving, so that the extending amount of the oil cylinder is limited, but the sensor has high requirements on the external environment, and the service life of the oil cylinder is shortened and the precision is influenced in severe environments such as water, dust, slurry and the like; the other is that the extension of the oil cylinder is limited by physical limitation or mechanical limitation, for example, the piston rod is limited by an external stop block, a boss or a mechanical pull rod, when the piston rod moves to a specified position, the piston rod can not move any more so as to forcibly limit the piston rod, and the cylinder rod is impacted by the limitation structure in such a way and is easy to deform and damage.

SUMMERY OF THE UTILITY MODEL

The utility model provides a telescoping cylinder, hydraulic system and operation machinery for solve among the prior art and carry out spacing mode through the sensor to the stroke of hydro-cylinder piston rod in the sensor easily receive external environment influence and life-span and influence the precision, or, spacing and easily make the jar pole of hydro-cylinder receive limit structure's the defect of impact deformation damage through physics.

The utility model provides a telescopic cylinder, include:

a piston rod;

the cylinder body is provided with a first through hole, a second through hole and a third through hole, the first through hole is communicated with the rodless cavity, the second through hole and the third through hole are communicated with the rod cavity, and the third through hole is used for being communicated with an external control source;

the limiting piece is arranged in the cylinder body in a sliding mode and used for adjusting the maximum moving stroke of the piston rod, the limiting piece and the piston rod can slide relatively, and the piston can abut against the limiting piece;

the limiting piece is positioned between the second through hole and the third through hole and is respectively in sealing fit with the rod part of the piston rod and the cylinder body; the limiting piece is provided with a first gap, and the first gap can be arranged opposite to the second port; the limiting part is provided with a second notch, and the second notch can be arranged opposite to the third opening.

According to the utility model provides a pair of telescopic cylinder, the cylinder body still is provided with spacing cavity, the locating part slides and sets up in the spacing cavity, the second opening with the third opening is located respectively the both ends of spacing cavity, just the second opening with the third opening all with spacing cavity intercommunication.

According to the utility model provides a pair of telescopic cylinder, the locating part includes:

the first limiting block is arranged in the limiting cavity in a sliding mode and is in sealing fit with the cylinder body;

the second limiting block is sleeved outside the rod part of the piston rod, the second limiting block and the rod part of the piston rod can slide relatively, and the second limiting block is in sealing fit with the rod part of the piston rod;

the first limiting block is connected with the second limiting block in a sliding mode, the first limiting block is matched with the second limiting block in a sealing mode, and the piston can abut against the first limiting block and/or the second limiting block.

According to the utility model provides a pair of telescopic cylinder, the locating part with be provided with first sealing member between the cylinder body, the locating part with be provided with the second sealing member between the pole portion of piston rod.

According to the utility model provides a pair of telescopic cylinder, the locating part still includes:

the piston rod is provided with a first limiting block, a second limiting block and at least one third limiting block, the first limiting block, the third limiting block and the second limiting block are sequentially distributed along the radial direction of the piston rod, and the first limiting block, the third limiting block and the second limiting block are sequentially connected in a sliding mode and are in sealing fit.

According to the utility model provides a pair of telescopic cylinder, the first end of first stopper is provided with first arch, the second end of second stopper is provided with the second arch, first arch with the second arch can offset, just first stopper with the second stopper homoenergetic with the second end wall of spacing cavity or the end cover of cylinder body offsets.

According to the utility model provides a pair of telescoping cylinder, first stopper with be provided with the third sealing member between the second stopper.

The utility model also provides a hydraulic system, including the pneumatic cylinder, the pneumatic cylinder is as above-mentioned arbitrary one the telescoping cylinder.

According to the utility model provides a pair of hydraulic system still includes the switching-over valve, the switching-over valve with the third port intercommunication of pneumatic cylinder.

The utility model also provides a working machine, include as above-mentioned arbitrary one the telescoping cylinder or as above-mentioned arbitrary one hydraulic system.

The utility model provides a telescopic cylinder, hydraulic system and operation machinery, telescopic cylinder include cylinder body, piston rod, locating part, are provided with first through hole, second through hole and third through hole on the cylinder body, and no pole chamber communicates with first through hole, and there is the pole chamber to communicate with the second through hole, so that gas or hydraulic oil can pass in and out no pole chamber from first through hole, and gas or hydraulic oil pass in and out there is the pole chamber from the second through hole, so as to realize the flexible of piston rod, and the third through hole is used for communicating with external control source; the limiting piece is arranged in the cylinder body in a sliding mode and used for adjusting the maximum moving stroke of the piston rod, the piston can abut against the limiting piece to enable the limiting piece to limit the piston rod, the limiting piece is respectively matched with the rod portion of the piston rod and the cylinder body in a sealing mode, and the limiting piece is located between the second opening and the third opening; when the external control source discharges oil or air through the third port to enable the pressure in the second chamber to be lower than the pressure of the first chamber or the pressure of the second chamber to be zero, the limiting piece can move to the second position, and at the moment, due to the limiting effect of the limiting piece, the piston of the piston rod can only move to the second position, so that the maximum moving stroke of the piston rod can be adjusted; and be provided with first breach and second breach on the locating part, can prevent that the locating part from plugging up second opening or third opening and can't be so that can't adjust the position of locating part through second opening or third opening oil feed or admit air.

So set up, can restrict the movement stroke of piston rod through the locating part to the position of locating part can be adjusted in the business turn over oil or business turn over gas of control third port, can adjust the biggest movement stroke of piston rod promptly, need not to detect the movement stroke of piston rod through the sensor or carry out rigidity spacing to the piston rod through setting up physics is spacing or mechanical spacing, has both improved the life of hydro-cylinder, can increase the application scope of telescoping cylinder again, with the normal operating requirement of satisfying mechanical structure.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is one of the cross-sectional views of the telescopic cylinder provided by the present invention (when the piston rod is not extended);

fig. 2 is a second cross-sectional view of the telescopic cylinder provided by the present invention (when the piston rod moves to the second position);

fig. 3 is a third cross-sectional view of the telescopic cylinder provided by the present invention (when the piston rod moves to the first position);

fig. 4 is a sectional view of a cylinder body of the telescopic cylinder provided by the present invention;

fig. 5 is a cross-sectional view of a limiting member of the telescopic cylinder provided by the present invention (the limiting member may include a first-level limiting member);

fig. 6 is a fourth cross-sectional view of the telescopic cylinder provided by the present invention (when the piston rod moves to the second position);

fig. 7 is a fifth cross-sectional view of the telescopic cylinder provided by the present invention (when the piston rod moves to the first position);

fig. 8 is a fifth cross-sectional view of the telescopic cylinder provided by the present invention (when the piston rod moves to the third position);

fig. 9 is a cross-sectional view of the limiting member of the telescopic cylinder provided by the present invention (the limiting member may include two-stage limiting members).

Reference numerals:

1. a cylinder body; 2. a piston rod; 3. a limiting member;

4. a first chamber; 5. a second chamber; 6. a first seal member;

7. a second seal member; 11. an end cap; 12. a first port;

13. a second port; 14. a third port; 15. a limiting chamber;

21. a piston; 22. a rod portion; 31. a first notch;

32. a second notch; 33. a first stopper; 34. a second limiting block;

35. a spring; 331. a first protrusion; 341. a second protrusion.

Detailed Description

To make the objects, technical solutions and advantages of the present invention clearer, the drawings of the present invention are combined to clearly and completely describe the technical solutions of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The telescopic cylinder, the hydraulic system and the working machine according to the present invention will be described with reference to fig. 1 to 9.

As shown in fig. 1 and fig. 2, the present invention provides a telescopic cylinder, which may include a cylinder body 1, a piston rod 2, and a limiting member 3.

Wherein, the piston rod 2 removes to set up in cylinder body 1 to the piston 21 of piston rod 2 can divide into the inner chamber of cylinder body 1 and have the pole chamber and no pole chamber, can be provided with first opening 12 and second opening 13 on the cylinder body 1, no pole chamber can communicate with first opening 12, have the pole chamber to communicate with second opening 13, so that gaseous or hydraulic oil can follow first opening 12 and advance out of no pole chamber, gaseous or hydraulic oil can follow second opening 13 and advance out of and have the pole chamber, in order to realize the flexible of piston rod 2.

The limiting piece 3 is slidably disposed in the cylinder 1, the limiting piece 3 can be used to adjust the maximum moving stroke of the piston rod 2, and the piston 21 can abut against the limiting piece 3, so that the limiting piece 3 can limit the piston rod 2.

Here, the limiting rod and the piston rod 2 can slide relative to each other to avoid that the limiting member 3 moves synchronously with the piston rod 2.

In addition, a third through hole 14 may be further formed in the cylinder 1, the third through hole 14 may be communicated with the rod cavity, and the limiting member 3 may be located between the second through hole 13 and the third through hole 14, and the limiting member 3 is respectively in sealing fit with the rod portion 22 of the piston rod 2 and the cylinder 1.

The limiting member 3 may divide the rod cavity into two chambers, a first chamber 4 and a second chamber 5, respectively, the first chamber 4 being located between the piston 21 and the limiting member 3, and the second chamber 5 being located between the limiting member 3 and the end cap 11 of the cylinder 1. The first chamber 4 is connected to the second port 13, and the second chamber 5 is connected to the third port 14.

When the third port 14 is controlled to be filled with oil or air and the pressure in the second chamber 5 is higher than the pressure in the rodless chamber, the limiting member 3 moves to the first position, and at this time, due to the limiting action of the limiting member 3, the piston 21 of the piston rod 2 can only move to the first position;

when the third port 14 is controlled to discharge oil or gas and the pressure in the second chamber 5 is lower than the pressure in the first chamber 4 or the pressure in the second chamber 5 is not high, the limiting member 3 moves to the second position, and at this time, the piston 21 of the piston rod 2 can only move to the second position due to the limiting action of the limiting member 3.

In addition, the limiting member 3 can be provided with a first notch 31, and the first notch 31 can be arranged opposite to the second through hole 13, so that the limiting member 3 provided with the first notch 31 can prevent the limiting member 3 from blocking the second through hole 13 and preventing oil or air from entering through the second through hole 13, and when oil or air enters through the second through hole 13, the limiting member 3 can be moved in a direction away from the rodless cavity when hydraulic oil or air impacts the first notch 31. Here, the first notch 31 may be provided at the first end of the limiting member 3.

The limiting member 3 may be provided with a second notch 32, and the second notch 32 may be arranged opposite to the third through opening 14. Thus, the second notch 32 is disposed on the limiting member 3 to prevent the limiting member 3 from blocking the third through hole 14 and preventing oil or air from entering through the third through hole 14, and when oil or air enters through the third through hole 14, the limiting member 3 is convenient to move toward the direction close to the rodless cavity when hydraulic oil or air impacts the second notch 32. Here, the second notch 32 may be provided at the second end of the limiting member 3.

So set up, can restrict the maximum movement stroke of piston rod 2 through locating part 3, and the position of locating part 3 can be adjusted to the business turn over oil or business turn over gas of control third through-hole 14, thereby can adjust the maximum movement stroke of piston rod 2, need not to detect the movement stroke of piston rod 2 through the sensor or carry out hard spacing to piston rod 2 through setting up physics is spacing or mechanical spacing, both improved the life of telescoping cylinder, can increase the application scope of telescoping cylinder again, in order to satisfy mechanical structure's normal operating requirement.

In the optional embodiment of the present invention, the cylinder body 1 may further be provided with a limiting cavity 15, and the limiting member 3 is slidably disposed in the limiting cavity 15. Here, the limiting member 3 may be in sealing engagement with the sidewall of the limiting chamber 15.

When the third port 14 is controlled to be filled with oil or air and the pressure in the second chamber 5 is higher than the pressure in the rodless chamber, the limiting member 3 can move to the first end of the limiting chamber 15 and abut against the first end wall of the limiting chamber 15, so that the limiting member 3 moves to the first position;

when the third port 14 is controlled to discharge oil or gas and the pressure in the second chamber 5 is lower than the pressure of the first chamber 4 or the pressure in the second chamber 5 is not high, the limiting member may move to the second end of the limiting chamber 15 and abut against the second end wall of the limiting chamber 15 or the end cover 11 of the cylinder 1, so that the limiting member 3 moves to the second position.

It should be noted that the first end wall of the check chamber 15 may be the end wall of the check chamber 15 close to the rodless cavity, and the second end wall of the check chamber 15 may be the end wall of the check chamber 15 far from the rodless cavity, where the stroke of the piston 21 moving to the first position is smaller than the stroke of the piston 21 moving to the second position.

In an optional embodiment of the present invention, a first sealing member 6 may be disposed between the limiting member 3 and the cylinder 1, and a second sealing member 7 may be disposed between the limiting member 3 and the rod portion 22 of the piston rod 2. Thus, the stopper 3 can be brought into sealing engagement with the cylinder 1 and the rod portion 22 of the piston rod 2, respectively, so that the first chamber 4 and the second chamber 5 can be prevented from communicating.

Specifically, the first sealing element 6 may be a first O-ring, the second sealing element 7 may be a second O-ring, a first groove is provided on the outer side wall of the limiting element 3, a second groove is provided on the inner side wall of the limiting element 3, the first O-ring may be embedded in the first groove, and the second O-ring may be embedded in the second groove.

In an optional embodiment of the present invention, the second and third through holes 13 and 14 may be respectively located at two ends of the limiting chamber 15, and both the second and third through holes 13 and 14 may communicate with the limiting chamber 15 to communicate with the first and second chambers 4 and 5 through the limiting chamber 15 and the limiting member 3.

In an alternative embodiment, the first end of the limiting member 3 may be provided with an axial protrusion, and when the limiting member 3 moves to the first end of the limiting chamber 15, the axial protrusion axially protrudes from the limiting chamber 15, and the piston 21 of the piston rod 2 moves to the first position to abut against the axial protrusion. In this way, the maximum stroke of the piston rod 2 can be further reduced.

In an optional embodiment of the present invention, the limiting member 3 may include a first limiting member 33 and a second limiting member 34, the first limiting member 33 is slidably disposed in the limiting cavity 15, and the first limiting member 33 may be in sealing fit with the cylinder body 1; the second limiting block 34 may be sleeved outside the rod portion 22 of the piston rod 2, the second limiting block 34 and the rod portion 22 of the piston rod 2 can slide relatively, and the second limiting block 34 may be in sealing fit with the rod portion 22 of the piston rod 2.

The first stopper 33 and the second stopper 34 can be slidably connected, and the first stopper 33 and the second stopper 34 can be in sealing fit, so that the first stopper 33 and the second stopper 34 can move relatively.

Furthermore, the piston 21 can abut against the first stopper 33 and/or the second stopper 34.

When oil or air enters the third opening 14 until the first limiting block 33 moves to abut against the first end wall of the limiting cavity 15, the piston 21 of the piston rod 2 can only move to the first position to abut against the first limiting block 33; when oil or air enters the third opening 14 until the first limit block 33 moves to abut against the first end wall of the limit cavity 15 and the second limit block 34 slides towards the direction of the rodless cavity to abut against the first limit block 33, the piston 21 of the piston rod 2 can only move to the third position to abut against the second limit block 34; when the third port 14 discharges oil or discharges air to enable the pressure in the cavity far away from the rodless cavity to be lower than the pressure in the cavity near the rodless cavity or the pressure in the cavity far away from the rodless cavity to be zero, the first limiting block 33 drives the second limiting block 34 to move to abut against the second end wall of the limiting cavity 15, and the piston 21 of the piston rod 2 can only move to the second position to abut against the first limiting block 33 and the second limiting block 34.

Therefore, the maximum stroke of the piston rod 2 can be adjusted in three stages by adjusting the relative positions of the first limiting block 33 and the second limiting block 34 under different pressures.

In an alternative embodiment, a first end of the first stopper 33 may be provided with a first protrusion 331, a second end of the second stopper 34 may be provided with a second protrusion 341, and the first protrusion 331 and the second protrusion 341 may abut against each other, so that when the second stopper 34 slides relative to the first stopper 33 until the second protrusion 341 abuts against the first protrusion 331, the second stopper 34 cannot slide continuously in the direction of the rodless cavity, and the interaction between the first protrusion 331 and the second protrusion 341 may prevent the second stopper 34 from disengaging from the first stopper 33, so that the second stopper 34 and the first stopper 33 are relatively fixed.

In addition, the first limiting block 33 and the second limiting block 34 can both abut against the second end wall of the limiting cavity 15 or the cylinder cover of the cylinder body 1, so that the piston rod 2 can be limited when the first limiting block 33 and the second limiting block 34 move to the second end of the limiting cavity 15.

In an alternative embodiment, a third sealing member may be disposed between the first stopper 33 and the second stopper 34, and the third sealing member may be located between the first projection 331 and the second projection 341. Thus, the degree of sealing between the first stopper 33 and the second stopper 34 can be improved.

In an alternative embodiment, a spring 35 may be disposed between the first stopper 33 and the second stopper 34, the spring 35 may be located between the first protrusion 331 and the second protrusion 341, and two ends of the spring 35 respectively abut against or are connected to the first protrusion 331 and the second protrusion 341. Therefore, the first limiting block 33 and the second limiting block 34 can be prevented from being in rigid contact through the spring 35, and the first limiting block 33 and the second limiting block 34 can be effectively prevented from being collided and abraded due to impact, so that the service lives of the first limiting block 33 and the second limiting block 34 can be prolonged.

The utility model discloses an in the optional embodiment, locating part 3 can also include at least one third stopper, and the third stopper can be followed piston rod 2's radial distribution in proper order to first stopper 33, third stopper and second stopper 34 sliding connection in proper order, first stopper 33, third stopper and second stopper 34 are sealed fit in proper order. Therefore, the first limiting block 33, the third limiting block and the second limiting block 34 can have different positions under different pressures, and the maximum stroke of the piston rod 2 can be adjusted in multiple stages by adjusting the relative positions of the first limiting block 33, the third limiting block and the second limiting block 34.

In an optional embodiment, fourth sealing elements are disposed between the third limiting blocks and the first limiting block 33 and the second limiting block 34, and fourth sealing elements are disposed between every two adjacent third limiting blocks, so as to prevent the first chamber 4 and the second chamber 5 from communicating and causing a pressure difference between the first chamber 4 and the second chamber 5, so that the position of the limiting member 3 cannot be adjusted.

The following describes the hydraulic system provided by the present invention, and the hydraulic system described below and the above-described telescopic cylinder can be referred to in correspondence.

The utility model provides a pair of hydraulic system can include the pneumatic cylinder, and the pneumatic cylinder can be as above-mentioned arbitrary embodiment the telescoping cylinder.

The utility model provides a beneficial effect that hydraulic system reached with the utility model provides a beneficial effect that the telescoping cylinder reached is unanimous, can restrict piston rod 2's removal stroke through locating part 3 to the business turn over oil of control third port 14 can be adjusted the position of locating part 3, thereby can adjust the maximum movement stroke of piston rod 2, can increase the application scope of telescoping cylinder, with the normal operating requirement that satisfies mechanical structure.

In an optional embodiment, the hydraulic system may further include a directional valve, the directional valve is communicated with the third port 14 of the hydraulic cylinder, and when it is required to control the maximum stroke of the piston 21 of the hydraulic cylinder to the first position, the directional valve may be controlled to feed oil into the third port 14, so that the pressure of the second chamber 5 of the hydraulic cylinder is greater than the pressure of the rodless chamber, and the position-limiting member 3 in the hydraulic cylinder is moved to the first end of the position-limiting chamber 15; when the maximum stroke of the piston 21 of the hydraulic cylinder is required to be controlled at the second position, the reversing valve can be controlled to reverse and make the hydraulic oil in the second chamber 5 of the hydraulic cylinder flow out from the third port 14, so that the pressure of the second chamber 5 of the hydraulic cylinder is smaller than the pressure of the first chamber 4 or no pressure, and the limiting member 3 can move to the second end of the limiting chamber 15.

The following describes the utility model provides a working machine, and the working machine of following description and the telescopic cylinder or the hydraulic system of the above-mentioned description can correspond the reference each other.

The utility model provides a pair of operation machinery can include telescopic cylinder or hydraulic system as above-mentioned arbitrary one embodiment.

The utility model provides a beneficial effect that operation machinery reached with the utility model provides a beneficial effect that telescoping cylinder or hydraulic system reached is unanimous, then no longer gives unnecessary details here.

It should be noted that the working machine may be a rotary drilling rig, a pump truck, a crane, an excavator, or other engineering machines or engineering vehicles.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims (10)

1. A telescopic cylinder, comprising:

a piston rod;

the cylinder body is provided with a first through hole, a second through hole and a third through hole, the first through hole is communicated with the rodless cavity, the second through hole and the third through hole are communicated with the rod cavity, and the third through hole is used for being communicated with an external control source;

the limiting piece is arranged in the cylinder body in a sliding mode and used for adjusting the maximum moving stroke of the piston rod, the limiting piece and the piston rod can slide relatively, and a piston of the piston rod can abut against the limiting piece;

the limiting piece is positioned between the second through hole and the third through hole and is respectively in sealing fit with the rod part of the piston rod and the cylinder body; the limiting piece is provided with a first gap, and the first gap can be arranged opposite to the second opening; the limiting part is provided with a second notch, and the second notch can be arranged opposite to the third opening.

2. The telescopic cylinder as claimed in claim 1, wherein the cylinder body further comprises a limiting chamber, the limiting member is slidably disposed in the limiting chamber, the second port and the third port are respectively located at two ends of the limiting chamber, and the second port and the third port are both communicated with the limiting chamber.

3. A telescopic cylinder according to claim 2, wherein the stop comprises:

the first limiting block is arranged in the limiting cavity in a sliding mode and is in sealing fit with the cylinder body;

the second limiting block is sleeved outside the rod part of the piston rod, the second limiting block and the rod part of the piston rod can slide relatively, and the second limiting block is in sealing fit with the rod part of the piston rod;

the first limiting block is connected with the second limiting block in a sliding mode, the first limiting block is matched with the second limiting block in a sealing mode, and the piston can abut against the first limiting block and/or the second limiting block.

4. A telescopic cylinder according to claim 1, wherein a first seal is provided between the stopper and the cylinder block, and a second seal is provided between the stopper and the rod portion of the piston rod.

5. A telescopic cylinder according to claim 3, wherein the stopper further comprises:

the piston rod is provided with a first limiting block, a second limiting block and at least one third limiting block, the first limiting block, the third limiting block and the second limiting block are sequentially distributed along the radial direction of the piston rod, and the first limiting block, the third limiting block and the second limiting block are sequentially connected in a sliding mode and are in sealing fit.

6. A telescopic cylinder according to claim 3, wherein a first protrusion is provided at a first end of the first stopper, a second protrusion is provided at a second end of the second stopper, the first protrusion and the second protrusion can abut against each other, and both the first stopper and the second stopper can abut against the second end wall of the limiting cavity or the end cap of the cylinder body.

7. A telescopic cylinder according to claim 3, wherein a third sealing element is provided between the first and second stop blocks.

8. A hydraulic system comprising a hydraulic cylinder, the hydraulic cylinder being a telescopic cylinder according to any of claims 1 to 7.

9. The hydraulic system of claim 8, further comprising a directional valve in communication with the third port of the hydraulic cylinder.

10. A working machine comprising a telescopic cylinder according to any of claims 1-7 or a hydraulic system according to claim 8 or 9.

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