Spring dead double piston oil cylinder

Abstract

A spring-loss double-piston oil cylinder belongs to the technical field of automotive parts. The purpose of the present invention is to improve the internal structure of the hydraulic cylinder and utilize the elastic force characteristics of the spring, thereby basically avoiding the problem of spring loss in the hydraulic cylinder. In the present invention, the piston rod is inserted into the cylinder body. A cab bottom bushing ring is fixedly installed at the upper end of the piston rod, and a vehicle body bushing ring is fixedly installed at the bottom end of the oil circuit base. A limiting barrier ring is provided in the middle of the piston rod extending into the cylinder body. The lower end of the piston rod extends into the piston, and the bottom end of the piston rod has a piston rod end head matching the inner diameter of the piston. The upper end of the piston has a piston end cover matching the outer diameter of the piston rod. A buffer spring is placed at the bottom of the piston interior. The middle part of the piston outer wall is divided into an upper oil chamber and a lower oil chamber by a sealing ring. The structure of the present invention is simple, the damping force is controllable, and the damping force can be adjusted according to the need by adjusting the spring stiffness; the problem of abnormal noise is solved, the damping force is reduced, and the abnormal noise generated during the driving of the hydraulic cylinder is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive parts. Background Art

[0002] The cab lifting hydraulic cylinder is a commonly used component. Its principle is to supply oil to both ends of the piston in the cylinder body, thereby completing the lifting or lowering of the cab by the hydraulic cylinder. The existing hydraulic rod is relatively simple, just a simple cylinder body with a piston inside. The piston is connected to a piston rod that extends out of the cylinder body. The bottom end of the cylinder body is installed on the axle beam of the vehicle body, and the extending end of the piston rod is installed on the axle beam at the bottom end of the cab. Both the cylinder body and the piston rod can rotate around their respective axle beams. Although this structure is simple, it has many drawbacks. For example: 1. When switching from lifting to lowering, or from lowering to lifting, due to the change in oil pressure at both ends of the piston, there is often jitter. Over time, it will damage components such as the hydraulic cylinder or pose a danger; 2. During the lifting or lowering process, due to uneven oil pressure, there is a high possibility of jitter, which is extremely dangerous and can sometimes cause casualties to personnel; and so on. In short, jitter is basically very dangerous. Summary of the Invention

[0003] The purpose of the present invention is to improve the internal structure of the hydraulic cylinder and utilize the elastic force characteristics of the spring to provide a spring jitter double piston oil cylinder that can basically avoid the problem of jitter in the hydraulic cylinder.

[0004] In the present invention, a piston rod is inserted into a cylinder body. A cab bottom shaft sleeve ring is fixedly installed at the upper end of the piston rod, and a vehicle body shaft sleeve ring is fixedly installed at the bottom end of an oil circuit base. A limiting barrier ring is arranged in the middle of the piston rod extending into the cylinder body. The lower end of the piston rod extends into a piston, and the bottom end of the piston rod has a piston rod end head matching the inner diameter of the piston. The upper end of the piston has a piston end cover matching the outer diameter of the piston rod. A buffer spring is placed at the bottom inside the piston. The middle part of the outer wall of the piston is divided into an upper oil cavity and a lower oil cavity by a sealing ring; Internal structure and oil circuit of the oil circuit base: An oil inlet passage and an oil return passage communicating with an external fuel tank are opened on the oil circuit base. The oil inlet passage is communicated with a first oil supply branch, and the first oil supply branch is communicated with a second oil supply branch. The inner diameter of the second oil supply branch is larger than that of the first oil supply branch. A spherical oil seal is arranged at the connection between the second oil supply branch and the first oil supply branch. One end of an oil pressure spring abuts against the inner wall of the oil circuit base, and the other end abuts against the bottom end of the spherical oil seal. The second oil supply branch communicates with the bottom end of the piston in the cylinder body through a third oil supply branch; The oil return passage is communicated with a first oil return branch. The first oil return branch is communicated with the upper end of the cylinder body through an oil return pipeline. The first oil return branch is blocked by a sealing cap, and the sealing cap is fixed on the oil circuit base. A return oil piston is arranged in the second oil return branch. A return oil branch sealing ring is sleeved on the outer wall of the return oil piston. The return oil branch sealing ring divides the second oil return branch into a front cavity of the second oil return branch and a rear cavity of the second oil return branch. The rear cavity of the second oil return branch is communicated with the first oil return branch, and the front cavity of the second oil return branch is communicated with the first oil supply branch. The front end of the return oil piston extends into the first oil supply branch and is a push rod corresponding to the spherical oil seal.

[0005] The structure of the present invention is simple, solving the problems of difficult processing technology and assembly technology of a double-oil hydraulic cylinder; The damping force is controllable, and the damping force can adjust the spring stiffness according to needs; The problem of abnormal noise is solved, the damping force is reduced, and abnormal noise generated during the driving of the hydraulic cylinder is avoided; There is no diameter-expanding structure, solving the problem of damage to the sealing ring of the differential cylinder; Small volume and light weight; Two wear-resistant rings are added to the piston to protect the sealing ring. Description of the Drawings

[0006] Figure 1 is a sectional view of the overall structure of the present invention;

[0007] Figure 2 is the present invention Figure 1 partial enlarged view of part A;

[0008] Figure 3 is the present invention Figure 1 sectional view taken along line B-B of the present invention. Detailed Embodiment

[0009] The piston rod 1 is inserted into the cylinder block 3. A cab bottom shaft sleeve ring 2 is fixedly installed at the upper end of the piston rod 1. A vehicle body shaft sleeve ring 5 is fixedly installed at the bottom end of the oil circuit base 6. This part adopts the same structure as the existing cab lifting device and is used for connecting the whole device with the cab and the vehicle body. The cab bottom shaft sleeve rings 2 at both ends of the whole device and the vehicle body shaft sleeve rings 5 are respectively connected to the shafts under the cab and on the vehicle frame body. The oil circuit base 6 also exists in the original equipment. The improvement of the present invention lies in the internal structure of the cylinder block and the oil circuit structure inside the oil circuit base 6.

[0010] In the present invention, a limit barrier ring 7 is provided in the middle of the piston rod 1 extending into the cylinder block 3. The limit barrier ring 7 is a snap ring. The limit barrier ring 7 is the upper limit position of the piston rod 1. That is to say, when the piston rod 1 extends out of the cylinder block 3, the barrier ring reaches the final position and cannot rise further. The position of the barrier limit of the limit barrier ring 7 can be set according to the actual situation.

[0011] The lower end of the piston rod 1 extends into the piston 13, and the bottom end of the piston rod 1 has a piston rod end 9 that matches the inner diameter of the piston 13. The upper end of the piston 13 has a piston end cover 12 that matches the outer diameter of the piston rod 1. The cooperation between the piston rod end 9 and the piston end cover 12 prevents the piston rod 1 from coming out of the piston 13.

[0012] A buffer spring 10 is placed at the bottom inside the piston 13. The elastic force of the buffer spring 10 is used to solve the problem of sudden movement and prevent sudden abnormal oil pressure conversion. Even if there is an abnormal oil pressure conversion, it will be absorbed by the buffer of this spring.

[0013] The middle part of the outer wall of the piston 13 divides the piston 13 into an upper oil chamber 8 and a lower oil chamber 14 through a sealing ring 11. This sealing ring 11 blocks the communication between the upper oil chamber 8 (descending oil chamber) and the lower oil chamber 14 (ascending oil chamber). The upper oil chamber 8 is also communicated with the outer oil chamber of the piston rod 1 inside the cylinder block 3 (this part is uniformly called the upper oil chamber 8 in the present invention), thus forming an ascending oil chamber and a descending oil chamber.

[0014] Internal structure and oil circuit of the oil circuit base 6: An oil inlet passage 25 and an oil return passage 22 communicating with an external fuel tank are opened on the oil circuit base 6. The oil inlet passage 25 is communicated with the first oil supply branch 18, the first oil supply branch 18 is communicated with the second oil supply branch 15, and the inner diameter of the second oil supply branch 15 is larger than that of the first oil supply branch 18. There is a spherical oil seal 27 at the connection of the second oil supply branch 15 and the first oil supply branch 18. One end of the oil pressure spring 28 abuts against the inner wall of the oil circuit base 6, and the other end abuts against the bottom end of the spherical oil seal 27. The second oil supply branch 15 communicates with the bottom end of the piston 13 in the cylinder block 3 through the third oil supply branch 17; the oil return passage 22 is communicated with the first oil return branch 26, the first oil return branch 26 communicates with the upper end of the cylinder block 3 through the oil return pipeline 4, the first oil return branch 26 is blocked by a sealing cap 21, and the sealing cap 21 is fixed on the oil circuit base 6. There is an oil return piston 20 in the second oil return branch 23, and an oil return branch sealing ring 29 is sleeved on the outer wall of the oil return piston 20. The oil return branch sealing ring 29 divides the second oil return branch 23 into a front chamber of the second oil return branch and a rear chamber of the second oil return branch. The rear chamber of the second oil return branch is communicated with the first oil return branch 26, and the front chamber of the second oil return branch is communicated with the first oil supply branch 18. The front end of the oil return piston 20 extends into the first oil supply branch 18 and is corresponding to the ejector rod 24 of the spherical oil seal 27. The internal oil circuit of the oil circuit base 6 is an oil supply passage for providing oil chambers for the cylinder block 3 to rise and fall. The oil supply line for the rising oil chamber is: the oil inlet passage 25, the first oil supply branch 18, the second oil supply branch 15, the third oil supply branch 17, and finally sent into the lower oil chamber 14. At this time, there is also oil in the second oil return branch 23, but it is sealed by the oil return branch sealing ring 29 outside the oil return piston 20 and will not be injected into the first oil return branch 26; the oil supply line for the falling oil chamber is: the oil return passage 22, the first oil return branch 26, the oil return pipeline 4, and finally injected into the upper oil chamber 8. The above-mentioned rising oil line is converted into an oil return passage to return the hydraulic oil to the fuel tank. While injecting oil into the upper oil chamber 8, the oil return piston 20 in the first oil return branch 26 will move towards the first oil supply branch 18, and the spherical oil seal 27 will be pushed open by the ejector rod 24, so that the oil in the lower oil chamber 14 finally returns to the fuel tank through the oil inlet passage 25.

[0015] Lifting process: The hydraulic oil enters the first oil supply branch 18 through the oil inlet passage 25, pushing open the spherical oil seal 27. The oil pressure spring 28 is compressed. The hydraulic oil enters the lower oil chamber 14 of the hydraulic cylinder from the second oil supply branch 15 along the third oil supply branch 17, pushing the piston 13 upward and compressing the buffer spring 10. When the buffer spring 10 is compressed to the limit position, it forms a rigid contact with the piston 1 and the piston 13. After there is no relative movement with the end of the piston rod 9, the piston 13 and the piston rod 1 coordinate to move upward together with the piston 13 and the buffer spring 10. The hydraulic oil in the upper oil chamber 8 enters the first oil return branch 26 through the oil return pipeline 4 and flows back into the manual pump housing along the oil return passage 22. When the cab flips over the center of gravity, the cab automatically flips. The buffer spring 10 will be released under the action of the elastic force, and the piston rod 1 and the piston 13 will have relative movement until the piston end cover 12 contacts the end of the piston rod 9, and the limit blocking ring 7 on the piston rod 1 contacts the guide sleeve to achieve the limit function. The hydraulic cylinder is lifted to the maximum position, and the hydraulic cylinder realizes the lifting.

[0016] Falling process: The hydraulic oil enters the first oil return branch 26 through the oil passage 22, pushing the oil return piston 20. The spherical oil seal 27 is pushed, and the oil pressure spring 28 is compressed. The third oil supply branch 17 is connected to the first oil supply branch 18. The hydraulic oil enters the upper oil chamber 8 through the oil return pipeline 4, pushing the piston 13 downward. The piston 13 is fixedly connected to the piston end cover 12, and the piston end cover 12 will drive the end of the piston rod 9 on the piston rod 1 downward. The compressed buffer spring 10 will be released, resulting in relative movement between the piston rod 1 and the piston 13 until the piston end cover 12 contacts the end of the piston rod 9. When the hydraulic cylinder starts to fall, the hydraulic oil in the lower oil chamber 14 of the hydraulic cylinder returns to the manual pump housing through the third oil supply branch 17 along the first oil supply branch 18 and the oil inlet passage 25, and the hydraulic cylinder realizes the descent. When the cab returns from the center of gravity, the instantaneous impact effect of the cab is reduced by compressing the buffer spring 10 to ensure that the cab can fall smoothly. At the same time, when the cab falls, the piston 13 needs to be lowered to the bottom of the hydraulic cylinder to ensure that the hydraulic cylinder can have enough movement distance during the next movement.

[0017] Slack movement process: When the hydraulic cylinder is in a vehicle moving normally, due to the damping effect of the cab, the hydraulic cylinder will be in a slack state. The piston rod 1 will reciprocate within the cylinder block 3 along with the bottom shaft sleeve ring 2 of the cab. Since the lower oil chamber 14 of the hydraulic cylinder cannot replenish the hydraulic cylinder, the piston 13 cannot move. The piston rod 1 and the piston rod end 9 will reciprocate up and down within the piston 13, and the buffer spring 10 in the piston 13 will be reciprocally compressed and released. The stiffness of the buffer spring 10 during the whole process should be less than the airbag damping force of the whole vehicle to ensure that the hydraulic cylinder will move with the whole vehicle. At the same time, to ensure the normal slack movement function of the hydraulic cylinder, the manual pump needs to use a three-position two-way commutation structure. In addition to the lifting and lowering states, a driving state needs to be added. In the driving state, the manual pump needs to seal the lifting oil port to prevent the piston from moving upward, and the lowering oil port needs to be connected to the housing to achieve oil suction and drainage in the upper chamber.

Claims

1. A spring-driven double-layer piston oil cylinder, with a piston rod (1) inserted into a cylinder block (3). A cab bottom shaft sleeve ring (2) is fixedly installed at the upper end of the piston rod (1), and a vehicle body shaft sleeve ring (5) is fixedly installed at the bottom end of an oil circuit base (6). It is characterized in that: A limit barrier ring (7) is provided in the middle of the piston rod (1) extending into the cylinder block (3). The lower end of the piston rod (1) extends into the piston (13), and the bottom end of the piston rod (1) has a piston rod end (9) matching the inner diameter of the piston (13). The upper end of the piston (13) has a piston end cover (12) matching the outer diameter of the piston rod (1). A buffer spring (10) is placed at the bottom inside the piston (13). The middle part of the outer wall of the piston (13) divides the piston (13) into an upper oil chamber (8) and a lower oil chamber (14) through a sealing ring (11); Internal structure and oil circuit of the oil circuit base (6): An oil inlet passage (25) and an oil return passage (22) communicating with an external oil tank are opened on the oil circuit base (6). The oil inlet passage (25) communicates with a first oil supply branch (18), and the first oil supply branch (18) communicates with a second oil supply branch (15). The inner diameter of the second oil supply branch (15) is larger than that of the first oil supply branch (18). A spherical oil seal (27) is provided at the connection between the second oil supply branch (15) and the first oil supply branch (18). One end of an oil pressure spring (28) abuts against the inner wall of the oil circuit base (6), and the other end abuts against the bottom end of the spherical oil seal (27). The second oil supply branch (15) communicates with the bottom end of the piston (13) in the cylinder block (3) through a third oil supply branch (17); The oil return passage (22) communicates with a first oil return branch (26). The first oil return branch (26) communicates with the upper end of the cylinder block (3) through an oil return pipe (4). The first oil return branch (26) is blocked by a sealing cap (21), and the sealing cap (21) is fixed on the oil circuit base (6). A return oil piston (20) is provided in the second oil return branch (23). A return oil branch sealing ring (29) is sleeved on the outer wall of the return oil piston (20). The return oil branch sealing ring (29) divides the second oil return branch (23) into a front chamber of the second oil return branch and a rear chamber of the second oil return branch. The rear chamber of the second oil return branch communicates with the first oil return branch (26), and the front chamber of the second oil return branch communicates with the first oil supply branch (18). The front end of the return oil piston (20) extends into the first oil supply branch (18) and is a push rod (24) corresponding to the spherical oil seal (27).

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