A piston stroke adjustment mechanism for a hydraulic cylinder of a dump truck

Abstract

The present invention discloses a piston stroke adjusting mechanism for a hydraulic cylinder of a dump truck, which includes a cylinder block, an oil inlet and an oil drain port. The oil inlet is provided below the surface of the cylinder block, and the oil drain port is provided above the surface of the cylinder block. A lower connector is arranged below the cylinder block, and a connecting seat is integrally arranged inside the lower connector. A lower buffer mechanism is installed below the interior of the cylinder block, and an upper buffer mechanism is installed above the interior of the cylinder block. For the piston stroke adjusting mechanism of the hydraulic cylinder of the dump truck, a plug body adjusting mechanism is provided, which can separate the pressing bolt from the rotating rod by rotating the pressing bolt, so that the rotating rod rotates in the second inner cavity, and then the positioning block on the movable block at the left end of the rotating rod is separated from the thread teeth on the surface of the connecting seat, thereby facilitating the threaded rotation of the connecting seat and the cylinder block, and facilitating the adjustment of the distance between the connecting seat and the internal piston, so as to conveniently adjust the stroke of the piston head in the hydraulic cylinder.

Description

Technical Field

[0001] The present invention relates to the technical field related to the hydraulic cylinder of a dump truck, and particularly to a piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck. Background Art

[0002] The hydraulic cylinder has a simple structure and reliable operation, and is widely used in dump trucks. The hydraulic cylinder of a dump truck is mainly used to control the lifting of the rear carriage of the dump truck. During its use, it is necessary to adjust the piston stroke to make the hydraulic cylinder meet the usage standards. For the existing piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck, there are still some defects, such as:

[0003] When the existing piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck is in use, the piston stroke adjustment is invariable. After adjustment, it is easy to affect the usage quality of the hydraulic cylinder. At the same time, the buffering effect inside the hydraulic cylinder is poor. During buffering, the piston rod cannot be locked to prevent the piston head from hitting the top of the cylinder body, which affects the service life of the hydraulic cylinder. In view of the above problems, an innovative design is carried out on the basis of the original piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck. Summary of the Invention

[0004] The purpose of the present invention is to provide a piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck to solve the problems in the above background art that the piston stroke adjustment inside the existing hydraulic cylinder of a dump truck is invariable, and the buffering effect inside the hydraulic cylinder is poor after adjustment, and it is easy for the piston head to hit the top of the cylinder body; it is realized that the hydraulic cylinder of the dump truck can automatically adjust the piston stroke, and when the piston rod inside the hydraulic cylinder works, it can buffer the internal piston rod to avoid the piston head hitting the top of the cylinder body.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck, including a cylinder body, an oil inlet and an oil drain port. The oil inlet is opened below the surface of the cylinder body, and the oil drain port is opened above the surface of the cylinder body. A lower connector is arranged below the cylinder body, and a connecting seat is integrally arranged inside the lower connector. A piston rod is arranged inside the cylinder body, and a piston head is fixed at the inner end of the piston rod. An upper connector is integrally arranged above the piston rod, and an air inlet hole is opened on the surface of the piston rod. A positioning rod is fixed in the middle of the connecting seat, and a rubber cover is fixed at the upper end of the positioning rod. A first inner cavity is opened inside the piston rod. A piston body adjusting mechanism is fixedly installed below the cylinder body, a lower buffering mechanism is installed below the inner part of the cylinder body, and an upper buffering mechanism is installed above the inner part of the cylinder body.

[0006] Preferably, the connecting seat is threadedly connected to the lower part of the cylinder body, and the positioning rod in the middle of the connecting seat and the rubber cover form a "T" - shaped structure, and the positioning rod penetrates through the inside of the piston rod and is connected to the first inner cavity.

[0007] Preferably, a gasket is arranged inside the first inner cavity, and the gasket is adhesively bonded above the piston head. At the same time, the positioning rod, rubber cover, plug rod, first inner cavity and air inlet hole form an air inlet mechanism.

[0008] Preferably, the plug body adjusting mechanism comprises an adjusting seat, a second inner cavity, a movable block, a positioning block, a first spring, a rotating rod and an extrusion bolt. The adjusting seat is integrally arranged below the cylinder block. A second inner cavity is formed between the adjusting seat and the cylinder block. The inner end of the second inner cavity is provided with the movable block. The outer end of the movable block is fixed with the positioning block. The outer side of the movable block is connected to the bottom of the second inner cavity on the surface of the adjusting seat through the first spring. A rotating rod is rotatably connected to the outer side of the inside of the adjusting seat, and an extrusion bolt is installed on the upper surface of the adjusting seat.

[0009] Preferably, the movable block and the second inner cavity on the surface of the adjusting seat form a sliding structure, and the positioning block on the surface of the movable block and the thread teeth on the surface of the connecting seat form an engaging structure.

[0010] Preferably, the lower buffer mechanism is composed of a lower buffer seat, and the lower buffer seat further comprises rubber rings, connecting pads and third springs. Connecting pads are connected between two adjacent rubber rings, and third springs are arranged on the outer sides of the rubber rings.

[0011] Preferably, the outer diameter of the rubber ring is matched with the inner diameter of the cylinder block. The third springs between two adjacent rubber rings are distributed in a staggered manner, and the lower part of the rubber ring is adhesively connected to the upper part of the connecting seat.

[0012] Preferably, the upper buffer mechanism comprises an upper buffer seat, a third inner cavity, a first buffer ring, a connecting rod, a second buffer ring and a second spring. The upper buffer seat is adhesively bonded to the top of the cylinder block. A third inner cavity is formed inside the upper buffer seat. The first buffer ring is arranged below the upper buffer seat. A connecting rod is fixed above the first buffer ring. The connecting rod penetrates through the upper buffer seat and is connected to the second buffer ring. A second spring is arranged on the outer side below the connecting rod. A locking mechanism is installed above the upper buffer seat.

[0013] Preferably, six groups of connecting rods are uniformly fixed between the first buffer ring and the second buffer ring. The connecting rods are slidably connected to the lower part of the upper buffer seat, and the inner diameter of the first buffer ring is matched with the outer diameter of the plug rod.

[0014] Preferably, the locking mechanism comprises a locking rod fixedly installed inside the upper buffer seat. A locking block is slidably connected to the inner end of the locking rod. A connecting hole is formed on the surface of the upper buffer seat. The outer end face of the locking block is arranged to be in conformity with the connecting hole on the surface of the upper buffer seat.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: For a piston stroke adjustment mechanism for a hydraulic cylinder of a dump truck,

[0016] 1. There are a positioning rod and a rubber cover. While the plug rod is moving, the rubber cover at the upper end of the positioning rod can perform a piston movement inside the plug rod, enabling the air intake holes on the outer surface of the plug rod to suck external air into the first inner cavity inside the plug rod, allowing the external air to contact the plug rod inside the cylinder block, facilitating the heat dissipation of the plug rod inside the cylinder block, and improving the heat dissipation effect of the hydraulic cylinder;

[0017] 2. There is a plug body adjustment mechanism. By rotating the extrusion bolt, the extrusion bolt can be separated from the rotating rod, enabling the rotating rod to rotate in the second inner cavity. Then, the positioning block on the movable block at the left end of the rotating rod is separated from the thread teeth on the surface of the connecting seat, facilitating the threaded rotation of the connecting seat and the cylinder block, and conveniently adjusting the distance between the connecting seat and the internal piston, thus conveniently adjusting the stroke of the piston head in the hydraulic cylinder;

[0018] 3. There are a lower buffer mechanism and an upper buffer mechanism. By using the rubber ring and the third spring inside the lower buffer mechanism and the first buffer ring and the second spring inside the upper buffer mechanism, it is convenient for the upper and lower buffer mechanisms to effectively buffer the internal piston, effectively avoiding the plug rod from hitting the upper and lower ends of the cylinder block, and effectively improving the service life of the hydraulic cylinder;

[0019] 4. By using the locking mechanism inside the upper buffer mechanism, it is convenient for the second buffer ring on the upper buffer mechanism to slide in the third inner cavity, enabling the generated air pressure to push the locking block slidably connected to the locking rod, facilitating the outward movement of the locking block, and then conveniently enabling the locking block to effectively lock the plug rod, improving the movement stability of the plug rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 is a schematic diagram of the front sectional structure of the present invention;

[0022] Figure 3 is of the present invention Figure 2 is a schematic diagram of the structure at A in

[0023] Figure 4 is of the present invention Figure 2 is a schematic diagram of the structure at B in

[0024] Figure 5 is a schematic diagram of the top sectional view of the adjustment seat of the present invention;

[0025] Figure 6 is a schematic diagram of the connection structure between the connecting seat and the lower buffer seat of the present invention;

[0026] Figure 7 This is a schematic diagram of the connection structure between the first buffer ring and the second buffer ring of the present invention.

[0027] In the figure: 1. Cylinder block; 2. Oil inlet; 3. Oil drain port; 4. Lower connector; 5. Plug rod; 6. Upper connector; 7. Air inlet hole; 8. Connection seat; 9. Positioning rod; 10. Rubber cover; 11. First inner cavity; 12. Piston head; 13. Sealing gasket; 14. Lower buffer seat; 141. Rubber ring; 142. Connection pad; 143. Third spring; 15. Adjusting seat; 16. Second inner cavity; 17. Movable block; 18. Positioning block; 19. First spring; 20. Rotating rod; 21. Extrusion bolt; 22. Upper buffer seat; 23. Third inner cavity; 24. Locking rod; 25. Locking block; 26. Connection hole; 27. First buffer ring; 28. Connecting rod; 29. Second buffer ring; 30. Second spring. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Please refer to Figure 1 , Figure 2 and Figure 6 , the present invention provides a technical solution: a piston stroke adjustment mechanism for a hydraulic cylinder of a dump truck, including a cylinder block 1, an oil inlet 2 and an oil drain port 3. In order to facilitate the heat dissipation of the hydraulic cylinder, an oil inlet 2 is opened below the surface of the cylinder block 1, and an oil drain port 3 is opened above the surface of the cylinder block 1. A lower connector 4 is provided below the cylinder block 1, and a connection seat 8 is integrally provided inside the lower connector 4. The connection seat 8 is threadedly connected to the lower part of the cylinder block 1, and a positioning rod 9 in the middle of the connection seat 8 and a rubber cover 10 form a "T" - shaped structure, and the positioning rod 9 passes through the inside of the plug rod 5 and is connected to the first inner cavity 11, which facilitates the disassembly of the connection seat 8 and the bottom of the cylinder block 1. A plug rod 5 is arranged inside the cylinder block 1, and a piston head 12 is fixed at the inner end of the plug rod 5. An upper connector 6 is integrally provided above the plug rod 5, and an air inlet hole 7 is opened on the surface of the plug rod 5. A sealing gasket 13 is arranged inside the first inner cavity 11, and the sealing gasket 13 is bonded above the piston head 12. At the same time, the positioning rod 9, the rubber cover 10, the plug rod 5, the first inner cavity 11 and the air inlet hole 7 form an air intake mechanism, which can make a piston movement of the rubber cover 10 at the end of the positioning rod 9 in the first inner cavity 11 inside the plug rod 5, facilitating the air intake hole 7 on the upper surface of the plug rod 5 to suck in external air, facilitating the heat exchange between the plug rod 5 inside the cylinder block 1 and the outside air, and facilitating the heat dissipation of the hydraulic cylinder;

[0030] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 5 For the convenience of adjusting the stroke of the piston head 12 inside the hydraulic cylinder, a positioning rod 9 can be fixed in the middle of the connecting seat 8, and a rubber cover 10 is fixed at the upper end of the positioning rod 9. A first inner cavity 11 is formed inside the plug rod 5, and a plug body adjusting mechanism is fixedly installed below the cylinder block 1. The plug body adjusting mechanism includes an adjusting seat 15, a second inner cavity 16, a movable block 17, a positioning block 18, a first spring 19, a rotating rod 20 and an extrusion bolt 21. The adjusting seat 15 is integrally arranged below the cylinder block 1. A second inner cavity 16 is formed between the adjusting seat 15 and the cylinder block 1. The inner end of the second inner cavity 16 is provided with a movable block 17. A positioning block 18 is fixed at the outer end of the movable block 17. The outer side of the movable block 17 is connected to the bottom of the second inner cavity 16 on the surface of the adjusting seat 15 through a first spring 19. A rotating rod 20 is rotatably connected to the outer side inside the adjusting seat 15, and an extrusion bolt 21 is installed on the upper surface of the adjusting seat 15. The movable block 17 and the second inner cavity 16 on the surface of the adjusting seat 15 form a sliding structure, and the positioning block 18 on the surface of the movable block 17 and the thread teeth on the surface of the connecting seat 8 form an engaging structure. By rotating the extrusion bolt 21, the extrusion bolt 21 can drive the rotating rod 20 to rotate inward, facilitating the extrusion of the movable block 17, so that the positioning block 18 at the inner end of the movable block 17 can catch the thread teeth on the surface of the connecting seat 8, thereby facilitating the positioning after the stroke adjustment of the piston head 12 inside the hydraulic cylinder.

[0031] Please refer to Figure 2 、 Figure 4 、 Figure 6 and Figure 7, for the buffer of the internal piston head 12 of the hydraulic cylinder, a lower buffer mechanism can be installed below the inside of the cylinder block 1. The lower buffer mechanism is composed of a lower buffer seat 14, and the lower buffer seat 14 further includes a rubber ring 141, a connecting pad 142 and a third spring 143. A connecting pad 142 is connected between two adjacent rubber rings 141. A third spring 143 is arranged on the outer side of the rubber ring 141. The outer diameter of the rubber ring 141 is matched with the inner diameter of the cylinder block 1. The third springs 143 between two adjacent rubber rings 141 are arranged in a staggered manner. The lower part of the rubber ring 141 is adhesively connected to the upper part of the connecting seat 8. By using the third springs 143 between the rubber rings 141 on the lower buffer seat 14, the lower end inside the cylinder block 1 can be buffered conveniently and effectively. An upper buffer mechanism is installed above the inside of the cylinder block 1. The upper buffer mechanism includes an upper buffer seat 22, a third inner cavity 23, a first buffer ring 27, a connecting rod 28, a second buffer ring 29 and a second spring 30. The upper buffer seat 22 is adhesively arranged on the top of the cylinder block 1. A third inner cavity 23 is opened inside the upper buffer seat 22. A first buffer ring 27 is arranged below the upper buffer seat 22. A connecting rod 28 is fixed above the first buffer ring 27. The connecting rod 28 passes through the upper buffer seat 22 and is connected to the second buffer ring 29. A second spring 30 is arranged on the outer side below the connecting rod 28. Six groups of connecting rods 28 are evenly fixed between the first buffer ring 27 and the second buffer ring 29. The connecting rod 28 is slidably connected to the lower part of the upper buffer seat 22. The inner diameter of the first buffer ring 27 is matched with the outer diameter of the plug rod 5. By using the first buffer ring 27 on the upper buffer mechanism in cooperation with the second spring 30 on the connecting rod 28, the upper part inside the cylinder block 1 can be buffered conveniently and effectively. A locking mechanism is installed above the upper buffer seat 22. The locking mechanism includes a locking rod 24 fixedly installed inside the upper buffer seat 22. A locking block 25 is slidably connected to the inner end of the locking rod 24. A connecting hole 26 is opened on the surface of the upper buffer seat 22. The outer end face of the locking block 25 is arranged to be in accordance with the connecting hole 26 on the surface of the upper buffer seat 22. When the locking block 25 on the locking mechanism is pushed by the second buffer ring 29, the locking block 25 can move outwards at the connecting hole 26 on the surface of the upper buffer seat 22, which is convenient for the locking block 25 to effectively press the plug rod 5, improving the locking after the buffering of the hydraulic cylinder and enhancing the safety of the use of the hydraulic cylinder.

[0032] Working principle: First, install the lower connector 4 and the upper connector 6 on the hydraulic cylinder on the dump truck. During use, hydraulic fluid can be poured into the interior of the cylinder body 1 through the oil inlet 2, causing the hydraulic fluid to squeeze the piston head 12 inside the cylinder body 1, making the piston head 12 move upward inside the cylinder body 1, and discharging the internal hydraulic fluid from the oil drain port 3, thereby facilitating the use of this hydraulic cylinder. A lower buffer mechanism is installed below the interior of this hydraulic cylinder. By using the rubber ring 141 and the third spring 143 on the lower buffer seat 14 inside the lower buffer mechanism, it is convenient and effective to buffer the lower part of the cylinder body 1, avoiding the piston head 12 hitting the lower part of the cylinder body 1. At the same time, an upper buffer mechanism is adhesively provided above the cylinder body 1. When the piston rod 5 drives the piston head 12 to move upward, the first buffer ring 27 below the upper buffer seat 22 made of rubber can move upward, causing the connecting rod 28 inside the first buffer ring 27 to slide on the upper buffer seat 22, and cooperating with the use of the second spring 30 outside the connecting rod 28, it is convenient for the first buffer ring 27 to effectively buffer the upward movement of the piston head 12, improving the buffering effect of the piston head 12. When the piston rod 5 moves, the rubber cover 10 at the end of the positioning rod 9 fixed in the middle of the connecting seat 8 can slide in the first inner cavity 11 inside the piston rod 5. The cross-sectional area of the rubber cover 10 is equal to the cross-sectional area inside the first inner cavity 11. Thus, when the piston rod 5 makes a piston movement, it is convenient for the positioning rod 9 to drive the rubber cover 10 to also make a piston movement inside the piston rod 5, so that the rubber cover 10 sucks external air into the first inner cavity 11 through the air inlet hole 7 on the surface of the piston rod 5, facilitating the adsorption of the heat generated by the work of the piston rod 5 by the external air, and thus facilitating the heat dissipation of this hydraulic cylinder;

[0033] When the first buffer ring 27 buffers, the second buffer ring 29 fixedly connected to the connecting rod 28 can slide in the third inner cavity 23 inside the upper buffer seat 22, causing the second buffer ring 29 to squeeze the locking block 25 on the locking mechanism, thereby causing the locking block 25 to slide outward on the locking rod 24, and thus effectively locking the piston rod 5, avoiding the piston rod 5 from moving outward, and improving the safety of the use of this hydraulic cylinder;

[0034] When it is necessary to adjust the stroke of the piston head 12, the extrusion bolt 21 on the surface of the adjusting seat 15 of the plug body adjusting mechanism can be rotated first, so that the extrusion bolt 21 moves upward on the adjusting seat 15, and then the rotating rod 20 in the second inner cavity 16 of the adjusting seat 15 rotates under the reset action of the elastically connected movable block 17, and then the positioning block 18 inside the movable block 17 is separated from the thread teeth on the surface of the connecting seat 8. Then, rotate the lower connector 4 so that the connecting seat 8 integrally arranged above the lower connector 4 moves in a threaded manner with the cylinder block 1, which is convenient for adjusting the distance between the lower buffer seat 14 above the connecting seat 8 and the piston head 12. Therefore, it is convenient to adjust the stroke used by the piston head 12. There are four groups of extrusion bolts 21 above the adjusting seat 15, which can effectively make the positioning block 18 catch the thread teeth on the surface of the connecting seat 8 when the stroke of the piston head 12 is adjusted, improving the stability of the adjustment of the cylinder block 1. This is the operating principle of the piston stroke adjusting mechanism for the hydraulic cylinder of a dump truck, and the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0035] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A piston stroke adjustment mechanism for a hydraulic cylinder of a dump truck, comprising a cylinder block (1) and an oil inlet (2) and an oil drain port (3), characterized in that: An oil inlet is provided below the surface of the cylinder block (1). (2), and an oil drain port (3) is provided above the surface of the cylinder block (1). Below the cylinder block (1) A lower connector (4) is provided, and a connecting seat (8) is integrally provided inside the lower connector (4). A piston rod (5) is provided inside the cylinder block (1), and a piston head (12) is fixed to the inner end of the piston rod (5). An upper connector (6) is integrally provided above the piston rod (5), and the piston rod (5) An air inlet hole (7) is provided on the surface of. A positioning rod (9) is fixed in the middle of the connecting seat (8), and A rubber cover (10) is fixed to the upper end of the positioning rod (9). A first Inner cavity (11) is provided inside the piston rod (5). A plug body adjustment mechanism is fixedly installed below the cylinder block (1). The cylinder block (1) A lower buffer mechanism is installed below the inside of, and an upper buffer mechanism is installed above the inside of the cylinder block (1). The upper buffer mechanism includes an upper buffer seat (22), a third inner cavity (23), a first buffer ring (27), A connecting rod (28), a second buffer ring (29) and a second spring (30). The upper buffer seat (22) is bonded And arranged on the top of the cylinder block (1), and a third inner cavity (23) is provided inside the upper buffer seat (22). A first buffer ring (27) is provided below the upper buffer seat (22), and the first buffer ring (27) A connecting rod (28) is fixed above. The connecting rod (28) penetrates through the upper buffer seat (22) and is connected to the second Buffer ring (29) is connected, and a second spring (30) is arranged outside the lower part of the connecting rod (28). A locking mechanism is installed above the upper buffer seat (22). The locking mechanism includes being fixedly installed on A locking rod (24) inside the upper buffer seat (22), and a lock is slidably connected to the inner end of the locking rod (24). Fixed block (25), and a connection hole (26) is provided on the surface of the upper buffer seat (22). The locking block (25) is arranged to fit the connection hole (26) on the surface of the upper buffer seat (22). The connection The seat (8) is threadedly connected to the lower part of the cylinder block (1), and the positioning rod (9) in the middle of the connection seat (8) and The rubber cover (10) form a "T" - shaped structure, and the positioning rod (9) penetrates through the inside of the piston rod (5) and is connected to the first Inner cavity (11) is connected. A sealing gasket (13) is provided inside the first inner cavity (11), and The sealing gasket (13) is bonded above the piston head (12). At the same time, the positioning rod (9), the rubber cover (10), The piston rod (5), the first inner cavity (11) and the air inlet hole (7) form an air inlet mechanism.

2. According to the piston stroke adjustment mechanism for a hydraulic cylinder of a dump truck described in claim 1, It is characterized in that: The plug body adjustment mechanism includes an adjustment seat (15), a second inner cavity (16), a movable Block (17), a positioning block (18), a first spring (19), a rotating rod (20) and an extrusion bolt (21). Moreover, the adjusting seat (15) is integrally provided below the cylinder block (1), and a second inner cavity (16) is formed between the adjusting seat (15) and the cylinder block (1). An inner end of the second inner cavity (16) is provided with a movable block (17). A positioning block (18) is fixed to an outer end of the movable block (17). The outer side of the movable block (17) is connected to a bottom of the second inner cavity (16) on a surface of the adjusting seat (15) through a first spring (19). Moreover, a rotating rod (20) is rotatably connected to an outer side inside the adjusting seat (15), and a pressing bolt (21) is mounted on an upper surface of the adjusting seat (15).

3. A piston stroke adjusting mechanism for a hydraulic cylinder of a dump truck according to claim 2, wherein the movable block (17) and the second inner cavity (16) on the surface of the adjusting seat (15) form a sliding structure, and a positioning block (18) on the surface of the movable block (17) and a thread tooth on the surface of the connecting seat (8) form an engaging structure.

4. A piston stroke adjusting mechanism for a hydraulic cylinder of a dump truck according to claim 1, It is characterized in that: wherein the lower buffer mechanism is composed of a lower buffer seat (14), and the lower buffer seat (14) further includes a rubber ring (141), a connecting pad (142) and a third spring (143). A connecting pad (142) is connected between two adjacent rubber rings (141), and a third spring (143) is arranged on an outer side of the rubber ring (141).

5. A piston stroke adjusting mechanism for a hydraulic cylinder of a dump truck according to claim 4, wherein an outer diameter of the rubber ring (141) is in conformity with an inner diameter of the cylinder block (1). The third springs (143) between two adjacent rubber rings (141) are distributed in a staggered manner, and a lower side of the lowermost rubber ring (141) and an upper side of the connecting seat (8) are adhesively connected.

6. A piston stroke adjusting mechanism for a hydraulic cylinder of a dump truck according to claim 1, It is characterized in that: wherein six groups of connecting rods (28) are uniformly fixed between the first buffer ring (27) and the second buffer ring (29). The connecting rods (28) are slidably connected to a lower side of the upper buffer seat (22), and an inner diameter of the first buffer ring (27) is in conformity with an outer diameter of the plug rod (5). ​ ​ ​ ​ It is characterized in that: ​ ​ ​ ​ It is characterized in that: ​ ​ ​

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