Engineering machinery oil cylinder and hydraulic control system thereof

Abstract

The invention relates to the technical field of hydraulic control, in particular to an engineering machinery oil cylinder and a hydraulic control system thereof.The engineering machinery oil cylinder comprises a cylinder body, a piston rod is arranged at the end of the cylinder body, a motor is arranged on the surface of the cylinder body, a rotating rod is arranged at the end of the motor, a jacking rod is fixed to the surface of the rotating rod, and an open groove is formed in the surface of the cylinder body; the top of the open groove is provided with a lifting block, the surface of the lifting block is provided with first teeth, the bottom of the lifting block is provided with a circular ring, the top of the lifting block is fixedly provided with a circular ring, the surface of the circular ring is fixedly provided with a vertical rod, the exterior of the vertical rod is provided with a circular plate, and the surface of the vertical rod is provided with a spring; the device has the beneficial effects that the first teeth are arranged on the surface of the lifting block, the first teeth are clamped in the second teeth along with descending of the lifting block, so that the position of the lifting block is stable, the lifting block is connected with the inserting rod, and after the inserting rod is kept stable, due to the fact that the inserting rod is fixed to the surface of the piston rod, the piston rod is kept stable.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and particularly to a construction machinery oil cylinder and its hydraulic control system. Background Art

[0002] A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion (or swinging motion). It is widely used in the hydraulic systems of various machines.

[0003] In the prior art, the patent number is CN113623287A, and the name is a construction machinery oil cylinder. An upper end cover is fixedly provided at the upper end of the cylinder block, and a lower end cover is fixedly provided at the lower end. A guide rod is provided at an eccentric position between the upper end cover and the lower end cover inside the cylinder block. A piston block is slidably connected inside the cylinder block along the vertical direction, and the piston block is slidably connected with the guide rod; a sliding hole is provided at the center of the piston block, and a piston body is slidably connected inside the sliding hole. A piston rod is provided at the upper end of the piston body. The cylinder block forms a rod chamber and a rodless chamber, and a first oil port and a second oil port are provided on the side surface of the cylinder block; a first chute is provided on the outer side of the piston body, and a rack is provided on the inner side wall of the sliding hole; an installation groove is provided inside the piston body, and a gear meshing with the rack is rotatably connected inside the installation groove. An adjustment assembly is provided inside the piston body, and a rotating block is rotatably connected inside the lower end cover; this construction machinery oil cylinder not only has a simple structure but also can realize the adjustment of the extending length of the piston rod.

[0004] However, the common locking method of existing hydraulic cylinders is to lock the oil cylinder by relying on the hydraulic circuit locking method, and use the oil pressure of the hydraulic oil in the oil cylinder to fix the piston rod. The hydraulic oil will deteriorate after long-term use, and the pressure of the hydraulic oil is insufficient, which may cause the piston rod to drop instantaneously. Summary of the Invention

[0005] The purpose of the present invention is to provide a construction machinery oil cylinder and its hydraulic control system to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A construction machinery oil cylinder, comprising:

[0007] A cylinder block, a piston rod is provided at the end of the cylinder block, a motor is provided on the surface of the cylinder block, a rotating rod is provided at the end of the motor, a holding rod is fixed on the surface of the rotating rod, a slot is provided on the surface of the cylinder block, a lifting block is provided at the top of the slot, a first tooth is provided on the surface of the lifting block, a ring is provided at the bottom of the lifting block, a ring is fixed at the top of the lifting block, a vertical rod is fixed on the surface of the ring, a circular plate is provided outside the vertical rod, and a spring is provided on the surface of the vertical rod.

[0008] Preferably, a fixing ring is fixed on the surface of the piston rod. A fourth screw hole is formed on the surface of the fixing ring. An adjusting plate is inserted into the surface of the fourth screw hole. The adjusting plate can move on the surface of the fixing ring. A fixing plate is fixed on the surface of the adjusting plate. A third screw hole is formed on the surface of the fixing plate. An L-shaped rod is fixed on the surface of the adjusting plate. The L-shaped rod moves along with the adjusting plate. An extension rod is fixed at the end of the L-shaped rod. The diameter of the extension rod is larger than that of the L-shaped rod. The other end of the extension rod is inserted with an insertion rod. The insertion rod can move inside the extension rod. The diameter of the insertion rod is smaller than that of the extension rod.

[0009] Preferably, a first screw hole is formed on the surface of the extension rod, and a second screw hole is formed on the surface of the insertion rod. A fixing block is fixed on the surface of the cylinder block. The insertion rod is inserted into the inside of the fixing block. The insertion rod can move inside the fixing block. The other end of the insertion rod is connected to a circular plate. The circular plate moves along with the insertion rod. A vertical rod is inserted into the surface of the circular plate. The vertical rod can move up and down inside the circular plate. A spring is arranged outside the vertical rod. One end of the spring is connected to the end of the vertical rod, and the other end is connected to the surface of the circular plate. The spring has a thrust on the vertical rod, so that the vertical rod is located at the top of the spring.

[0010] Preferably, the motor can drive the rotating rod to rotate. The rotating rod drives the supporting rod to rotate. The circle of the rotating rod is located at the bottom of the center of the supporting rod. A through hole is formed inside the ring. The supporting rod is inserted into the through hole inside the ring. The supporting rod can rotate in the through hole. After the supporting rod rotates, it supports on the surface of the through hole, so that the ring moves.

[0011] Preferably, first tooth teeth are arranged on both sides of the lifting block. The first tooth teeth rise and fall along with the lifting block. After the lifting block descends, it can be inserted into the slot. Second tooth teeth are arranged on both sides of the slot. When the lifting block is inserted into the slot, the first tooth teeth on the surface of the lifting block can be stuck in the second tooth teeth on both sides of the slot. Air outlet holes are formed on both sides of the lifting block. A rubber pad is fixed at the bottom of the lifting block. An air groove is formed inside the rubber pad. There is air in the air groove. The air can enter the air groove through the air outlet holes. When the rubber pad is squeezed, the air in the air groove is ejected through the air outlet holes.

[0012] Preferably, a vertical pipe is fixed at the bottom of the slot. A lifting rod is inserted into the top of the vertical pipe. The lifting rod can move up and down inside the vertical pipe. A spring is arranged inside the vertical pipe. The spring is connected to the inside of the vertical pipe and the end of the lifting rod. The spring in the vertical pipe has a thrust on the lifting rod, so that the lifting rod is located at the top of the vertical pipe. And the other end of the lifting rod is fixed with a baffle. The baffle rises and falls along with the lifting rod. The baffle is located in the slot.

[0013] Preferably, a clamping groove is formed on the surface of the supporting rod, and a clamping plate is fixed in the through hole inside the ring. When the supporting rod rotates in the through hole, the clamping plate can be inserted into the clamping groove on the surface of the supporting rod. A through groove is formed on the surface of the cylinder block. There are two groups of through grooves, which are communicated with the inside of the slotted groove and are located on both sides of the slotted groove.

[0014] Preferably, the supporting rod is elliptical, and the fixing point of the rotating rod and the supporting rod is located on one side of the supporting rod. When the rotating rod drives the supporting rod to rotate, the side of the supporting rod away from the rotating rod can abut against the surface of the through hole inside the ring, and the ring moves under the abutment of the supporting rod.

[0015] Preferably, when the lifting block descends and is inserted into the slotted groove, the rubber pad at the bottom of the lifting block first abuts against the surface of the first tooth in the slotted groove, causing the first tooth to descend. And because the rubber pad is squeezed, the air in the air groove is blown out through the air outlet hole, and the air blown out of the air outlet hole blows on the surface of the second tooth.

[0016] A hydraulic control system includes the above-mentioned construction machinery oil cylinder.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] When the position of the piston rod needs to be fixed in the present invention, the motor drives the rotating rod to rotate, the rotating rod drives the supporting rod to rotate, the clamping plate moves out of the clamping groove, the other end of the supporting rod abuts against the surface of the through hole, causing the ring to descend, the ring drives the lifting block to descend, the bottom of the lifting block abuts against the surface of the baffle plate, and the baffle plate is located at the top of the slotted groove under the abutment of the lifting rod. When the lifting block presses down the baffle plate, the baffle plate descends in the slotted groove, and the lifting rod is inserted into the vertical pipe. The rubber pad is squeezed, so that the air in the air groove is blown out through the air outlet hole, and the air blown out of the air outlet hole blows on the surface of the second tooth, blowing out the dust and impurities in the second tooth. And the surface of the lifting block is provided with first teeth, and the first teeth are stuck in the second teeth after the lifting block descends, so that the position of the lifting block is stable. The lifting block is connected to the plugging rod. After the plugging rod is stable, since the plugging rod is fixed to the surface of the piston rod, the piston rod is kept stable. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the present invention.

[0020] Figure 2 It is a schematic structural diagram of another perspective of the present invention.

[0021] Figure 3 It is a schematic diagram of a partially enlarged structure of the present invention.

[0022] Figure 4 It is a schematic diagram of another partially enlarged structure of the present invention.

[0023] Figure 5 is Figure 4 The enlarged schematic diagram of the structure at position A in

[0024] Figure 6 This is the schematic diagram of the sectional structure of the present invention.

[0025] Figure 7 is Figure 6 The enlarged schematic diagram of the structure at position B in

[0026] Figure 8 This is the schematic diagram of the sectional structure of the present invention from another perspective.

[0027] Figure 9 is Figure 8 The enlarged schematic diagram of the structure at position C in

[0028] Figure 10 is Figure 8 The enlarged schematic diagram of the structure at position D in

[0029] In the figure: cylinder block 1, piston rod 2, fixing ring 3, fixing plate 4, L-shaped rod 5, adjusting plate 6, extension rod 7, inserting rod 8, fixing block 9, through slot 10, vertical rod 11, spring 12, circular plate 13, holding rod 14, lifting block 15, first tooth 16, air outlet 17, circular ring 18, second tooth 19, slotted hole 20, rotating rod 21, motor 22, through hole 23, lifting rod 24, vertical pipe 25, baffle 26, air groove 27, rubber pad 28, clamping slot 29, clamping plate 30, first screw hole 31, second screw hole 32, third screw hole 33, fourth screw hole 34. Detailed implementation manners

[0030] In order to clearly and completely describe the purpose, technical solution of the present invention and make the advantages more clearly understood, the following further details the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, not to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0031] Please refer to Figures 1 to 10 , the present invention provides a technical solution:

[0032] Embodiment 1: An engineering machinery oil cylinder, comprising: a cylinder block 1, a piston rod 2 is arranged at the end of the cylinder block 1, a motor 22 is arranged on the surface of the cylinder block 1, a rotating rod 21 is arranged at the end of the motor 22, a holding rod 14 is fixed on the surface of the rotating rod 21, a slot 20 is formed on the surface of the cylinder block 1, a lifting block 15 is arranged at the top of the slot 20, a first tooth 16 is arranged on the surface of the lifting block 15, a circular ring 18 is arranged at the bottom of the lifting block 15, a circular ring 18 is fixed at the top of the lifting block 15, a vertical rod 11 is fixed on the surface of the circular ring 18, a circular plate 13 is arranged outside the vertical rod 11, and a spring 12 is arranged on the surface of the vertical rod 11.

[0033] Embodiment 2: On the basis of Embodiment 1, a fixing ring 3 is fixed on the surface of the piston rod 2. A fourth screw hole 34 is formed on the surface of the fixing ring 3. An adjusting plate 6 is inserted into the surface of the fourth screw hole 34. The adjusting plate 6 can move on the surface of the fixing ring 3. A fixing plate 4 is fixed on the surface of the adjusting plate 6. A third screw hole 33 is formed on the surface of the fixing plate 4. An L-shaped rod 5 is fixed on the surface of the adjusting plate 6. The L-shaped rod 5 moves along with the adjusting plate 6. An extension rod 7 is fixed at the end of the L-shaped rod 5. The diameter of the extension rod 7 is larger than that of the L-shaped rod 5. The other end of the extension rod 7 is inserted with an insertion rod 8. The insertion rod 8 can move inside the extension rod 7. The diameter of the insertion rod 8 is smaller than that of the extension rod 7. First tooth teeth 16 are arranged on both sides of the lifting block 15. The first tooth teeth 16 move up and down along with the lifting block 15. After the lifting block 15 descends, it can be inserted into a slot 20. Second tooth teeth 19 are arranged on both sides of the slot 20. When the lifting block 15 is inserted into the slot 20, the first tooth teeth 16 on the surface of the lifting block 15 can be stuck in the second tooth teeth 19 on both sides of the slot 20. Air outlet holes 17 are formed on both sides of the lifting block 15. A rubber pad 28 is fixed at the bottom of the lifting block 15. An air groove 27 is formed inside the rubber pad 28. There is air in the air groove 27. The air can enter the air groove 27 through the air outlet holes 17. And when the rubber pad 28 is squeezed, the air in the air groove 27 is ejected through the air outlet holes 17. A vertical pipe 25 is fixed at the bottom of the slot 20. A lifting rod 24 is inserted into the top of the vertical pipe 25. The lifting rod 24 can move up and down inside the vertical pipe 25. A spring is arranged inside the vertical pipe 25. The spring connects the inside of the vertical pipe 25 and the end of the lifting rod 24. The spring in the vertical pipe 25 has a thrust on the lifting rod 24, so that the lifting rod 24 is located at the top of the vertical pipe 25. And the other end of the lifting rod 24 is fixed with a baffle 26. The baffle 26 moves up and down along with the lifting rod 24. The baffle 26 is located in the slot 20. When the lifting block 15 descends and is inserted into the slot 20, the rubber pad 28 at the bottom of the lifting block 15 first abuts against the surface of the first tooth teeth 16 in the slot 20, so that the first tooth teeth 16 descend. And because the rubber pad 28 is squeezed, the air in the air groove 27 is blown out through the air outlet holes 17. The air blown out from the air outlet holes 17 blows on the surface of the second tooth teeth 19. The lifting rod 24 is inserted into the vertical pipe 25. The rubber pad 28 is squeezed, so that the air in the air groove 27 is blown out through the air outlet holes 17. The air blown out from the air outlet holes 17 blows on the surface of the second tooth teeth 19, blowing away the dust and impurities located in the second tooth teeth 19. And first tooth teeth 16 are arranged on the surface of the lifting block 15. After the first tooth teeth 16 descend along with the lifting block 15, they are stuck in the second tooth teeth 19, so that the position of the lifting block 15 is stable. The lifting block 15 is connected to the insertion rod 8. After the insertion rod 8 is stable, because the insertion rod 8 is fixed to the surface of the piston rod 2, the piston rod 2 is kept stable.

[0034] The surface of the extension rod 7 is provided with a first screw hole 31, the surface of the insertion rod 8 is provided with a second screw hole 32, a fixing block 9 is fixed on the surface of the cylinder block 1, the insertion rod 8 is inserted into the inside of the fixing block 9, the insertion rod 8 can move inside the fixing block 9, the other end of the insertion rod 8 is connected to a circular plate 13, the circular plate 13 moves along with the insertion rod 8, a vertical rod 11 is inserted into the surface of the circular plate 13, the vertical rod 11 can move up and down inside the circular plate 13, a spring 12 is arranged outside the vertical rod 11, one end of the spring 12 is connected to the end of the vertical rod 11, and the other end is connected to the surface of the circular plate 13. The spring 12 has a thrust on the vertical rod 11, so that the vertical rod 11 is located at the top of the spring 12.

[0035] The motor 22 can drive the rotating rod 21 to rotate, the rotating rod 21 drives the supporting rod 14 to rotate. The circle of the rotating rod 21 is located at the bottom of the center of the supporting rod 14. A through hole 23 is opened inside the ring 18, the supporting rod 14 is inserted into the through hole 23 inside the ring 18, the supporting rod 14 can rotate in the through hole 23, after the supporting rod 14 rotates, it abuts against the surface of the through hole 23, so that the ring 18 moves. A clamping groove 29 is opened on the surface of the supporting rod 14, a clamping plate 30 is fixed in the through hole 23 inside the ring 18. When the supporting rod 14 rotates in the through hole 23, the clamping plate 30 can be inserted into the clamping groove 29 on the surface of the supporting rod 14. A through groove 10 is opened on the surface of the cylinder block 1, there are two groups of through grooves 10, the through grooves 10 communicate with the inside of the slot 20, the through grooves 10 are located on both sides of the slot 20. The supporting rod 14 is oval, and the fixed point of the rotating rod 21 and the supporting rod 14 is located on one side of the supporting rod 14. When the rotating rod 21 drives the supporting rod 14 to rotate, the side of the supporting rod 14 away from the rotating rod 21 can abut against the surface of the through hole 23 inside the ring 18. Under the abutment of the supporting rod 14, the ring 18 moves, and the clamping plate 30 moves out of the clamping groove 29. The other end of the supporting rod 14 abuts against the surface of the through hole 23, so that the ring 18 descends. The ring 18 drives the lifting block 15 to descend. The bottom of the lifting block 15 abuts against the surface of the baffle 26. The baffle 26 is located at the top of the slot 20 under the abutment of the lifting rod 24. When the lifting block 15 presses down the baffle 26, the baffle 26 descends in the slot 20, and the lifting rod 24 is inserted into the vertical pipe 25, and the rubber pad 28 is extruded, so that the air in the air groove 27 is blown out through the air outlet 17.

[0036] The piston rod 2 can telescopically move at the end of the cylinder block 1. The fixing ring 3 is fixed at the end of the piston rod 2. The adjusting plate 6 is fixed on the surface of the fixing ring 3 through a screw, and the position of the adjusting plate 6 can be adjusted. The insertion rod 8 is inserted inside the extension rod 7, and the extension rod 7 and the insertion rod 8 can be fixed through a screw. When the position of the piston rod 2 needs to be fixed, the rotating rod 21 is driven to rotate by the motor 22. The rotating rod 21 drives the holding rod 14 to rotate, and the clamping plate 30 moves out of the clamping groove 29. The other end of the holding rod 14 abuts against the surface of the through hole 23, causing the circular ring 18 to descend. The circular ring 18 drives the lifting block 15 to descend. The bottom of the lifting block 15 abuts against the surface of the baffle plate 26. The baffle plate 26 is located at the top of the slot 20 under the abutment of the lifting rod 24. When the lifting block 15 presses down the baffle plate 26, the baffle plate 26 descends in the slot 20, and the lifting rod 24 is inserted into the vertical pipe 25. The rubber pad 28 is squeezed, so that the air in the air groove 27 is blown out through the air outlet hole 17. The air blown out from the air outlet hole 17 blows on the surface of the second tooth 19, and the dust and impurities located in the second tooth 19 are blown away. Moreover, the surface of the lifting block 15 is provided with a first tooth 16. After the first tooth 16 descends with the lifting block 15, it is stuck in the second tooth 19, making the position of the lifting block 15 stable. The lifting block 15 is connected to the insertion rod 8. After the insertion rod 8 is stable, since the insertion rod 8 is fixed to the surface of the piston rod 2, the piston rod 2 is kept stable. And the dust in the slot 20 can be blown out from the through slot 10. After the lifting block 15 rises, the holding rod 14 rotates so that the clamping plate 30 is inserted into the clamping groove 29, which can keep the lifting block 15 stable.

[0037] Although the above-described illustrative specific embodiments of the present application have been described to enable those skilled in the art to understand the present application, the present application is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present application defined and determined by the appended claims, all application creations using the concept of the present application are within the scope of protection.

Claims

1. An engineering machinery oil cylinder, characterized in that: Comprising: A cylinder block (1), a piston rod (2) is provided at the end of the cylinder block (1), a motor (22) is provided on the surface of the cylinder block (1), a rotating rod (21) is provided at the end of the motor (22), a holding rod (14) is fixed on the surface of the rotating rod (21), a slot (20) is formed on the surface of the cylinder block (1), a lifting block (15) is provided at the top of the slot (20), a first tooth (16) is provided on the surface of the lifting block (15), a ring (18) is provided at the bottom of the lifting block (15), a ring (18) is fixed at the top of the lifting block (15), a vertical rod (11) is fixed on the surface of the ring (18), a circular plate (13) is provided outside the vertical rod (11), and a spring (12) is provided on the surface of the vertical rod (11).

2. The construction machinery oil cylinder according to claim 1, wherein: A fixing ring (3) is fixed on the surface of the piston rod (2), a fourth screw hole (34) is formed on the surface of the fixing ring (3), an adjusting plate (6) is inserted into the surface of the fourth screw hole (34), the adjusting plate (6) can move on the surface of the fixing ring (3), a fixing plate (4) is fixed on the surface of the adjusting plate (6), a third screw hole (33) is formed on the surface of the fixing plate (4), an L-shaped rod (5) is fixed on the surface of the adjusting plate (6), the L-shaped rod (5) moves along with the adjusting plate (6), an extension rod (7) is fixed at the end of the L-shaped rod (5), the diameter of the extension rod (7) is larger than that of the L-shaped rod (5), the other end of the extension rod (7) is inserted with an insertion rod (8), the insertion rod (8) can move inside the extension rod (7), and the diameter of the insertion rod (8) is smaller than that of the extension rod (7).

3. The hydraulic cylinder of a construction machinery according to claim 2, wherein: A first screw hole (31) is formed on the surface of the extension rod (7), a second screw hole (32) is formed on the surface of the insertion rod (8), a fixing block (9) is fixed on the surface of the cylinder block (1), the insertion rod (8) is inserted into the fixing block (9), the insertion rod (8) can move inside the fixing block (9), the other end of the insertion rod (8) is connected to the circular plate (13), the circular plate (13) moves along with the insertion rod (8), a vertical rod (11) is inserted into the surface of the circular plate (13), the vertical rod (11) can move up and down inside the circular plate (13), a spring (12) is provided outside the vertical rod (11), one end of the spring (12) is connected to the end of the vertical rod (11), and the other end is connected to the surface of the circular plate (13). The spring (12) has a thrust on the vertical rod (11) so that the vertical rod (11) is located at the top of the spring (12).

4. The hydraulic cylinder for construction machinery according to claim 3, wherein: The motor (22) can drive the rotating rod (21) to rotate, the rotating rod (21) drives the holding rod (14) to rotate, the circle of the rotating rod (21) is located at the bottom of the center of the holding rod (14), a through hole (23) is formed inside the ring (18), the holding rod (14) is inserted into the through hole (23) inside the ring (18), the holding rod (14) can rotate in the through hole (23), and after the holding rod (14) rotates, it abuts against the surface of the through hole (23) to move the ring (18).

5. The hydraulic cylinder for construction machinery according to claim 4, characterized in that: On both sides of the lifting block (15), there are first teeth (16). The first teeth (16) move up and down with the lifting block (15). After the lifting block (15) descends, it can be inserted into the slot (20). On both sides of the slot (20), there are second teeth (19). When the lifting block (15) is inserted into the slot (20), the first teeth (16) on the surface of the lifting block (15) can be stuck in the second teeth (19) on both sides of the slot (20). On both sides of the lifting block (15), there are air holes (17). At the bottom of the lifting block (15), there is a rubber pad (28) fixed. Inside the rubber pad (28), there is an air groove (27). There is air in the air groove (27), and the air can enter the air groove (27) through the air holes (17). When the rubber pad (28) is squeezed, the air in the air groove (27) is ejected through the air holes (17).

6. The hydraulic cylinder for construction machinery according to claim 5, wherein: At the bottom of the slot (20), there is a vertical pipe (25) fixed. At the top of the vertical pipe (25), there is a lifting rod (24) inserted. The lifting rod (24) can move up and down inside the vertical pipe (25). Inside the vertical pipe (25), there is a spring. The spring connects the inside of the vertical pipe (25) and the end of the lifting rod (24). The spring in the vertical pipe (25) has a thrust on the lifting rod (24), making the lifting rod (24) located at the top of the vertical pipe (25). And at the other end of the lifting rod (24), there is a baffle (26) fixed. The baffle (26) moves up and down with the lifting rod (24). The baffle (26) is located in the slot (20). After the lifting block (15) presses down the baffle (26), the baffle (26) descends in the slot (20), and the lifting rod (24) is inserted into the vertical pipe (25). The rubber pad (28) is squeezed, making the air in the air groove (27) blow out through the air holes (17).

7. The hydraulic cylinder for construction machinery according to claim 6, wherein: On the surface of the holding rod (14), there is a card slot (29). Inside the through hole (23) of the ring (18), there is a card board (30) fixed. When the holding rod (14) rotates in the through hole (23), the card board (30) can be inserted into the card slot (29) on the surface of the holding rod (14). On the surface of the cylinder block (1), there are two groups of through grooves (10). The through grooves (10) are communicated with the inside of the slot (20). The through grooves (10) are located on both sides of the slot (20). The dust in the slot (20) can be blown out from the through grooves (10).

8. The hydraulic cylinder of a construction machinery according to claim 7, characterized in that: The holding rod (14) is oval, and the fixed point of the rotating rod (21) and the holding rod (14) is located on one side of the holding rod (14). When the rotating rod (21) drives the holding rod (14) to rotate, the side of the holding rod (14) away from the rotating rod (21) can hold against the surface of the through hole (23) inside the ring (18). Under the holding of the holding rod (14), the ring (18) moves. After the lifting block (15) rises, the holding rod (14) rotates to make the card board (30) inserted into the card slot (29), which can keep the lifting block (15) stable.

9. The hydraulic cylinder for construction machinery according to claim 8, characterized in that: When the lifting block (15) descends and is inserted into the slot (20), the rubber pad (28) at the bottom of the lifting block (15) first abuts against the surface of the first tooth (16) in the slot (20), causing the first tooth (16) to descend. And because the rubber pad (28) is squeezed, the air in the air groove (27) is blown out through the air outlet hole (17), and the air blown out from the air outlet hole (17) blows on the surface of the second tooth (19).

10. A hydraulic control system, characterized in that: Including the construction machinery oil cylinder according to claim 9 above.

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