A hydraulic cylinder buffer system

Abstract

The present invention discloses a hydraulic cylinder buffer system, including a two-position four-way electromagnetic reversing valve and a one-way valve group. One end of the two-position four-way electromagnetic reversing valve is connected to two pipelines, and the other end is respectively connected to the one-way valve group and the pipeline. The one-way valve group includes a first one-way valve and a second one-way valve in parallel, and a throttle valve connected in series with the second one-way valve. The first one-way valve flows toward the hydraulic cylinder, and the second one-way valve flows away from the hydraulic cylinder. The hydraulic cylinder buffer system disclosed in the present invention improves the stability of the whole machine and the comfort of operation, reduces the physical impact of the piston on the cylinder, and prolongs the service life of the cylinder. It has a simple structure, a small number of hydraulic components, a low cost, and is more practical.

Description

Technical Field

[0001] The invention relates to a buffer system, in particular to a hydraulic cylinder buffer system. Background Art

[0002] During rapid movement, the hydraulic cylinder will generate strong impact, noise and even mechanical collisions such as tie rods at the end of the stroke. Especially under high pressure, this effect is more obvious, seriously affecting the service life of the cylinder. Therefore, proper braking and buffering must be performed before the end of the movement to ensure the service life of the system and the cylinder. At present, most of the hydraulic cylinders used in loaders have little buffer design (such as bucket cylinders). They only have a margin in the cylinder stroke and rely on the physical impact between the working device and the limit block to limit the position to avoid the tie rod. However, due to the strong physical impact, on the one hand, it affects the stability of the whole machine and the comfort of operation. On the other hand, due to the reaction of the physical impact, the cylinder will also bear a reaction force, which affects the service life of the cylinder.

[0003] The hydraulic system with buffer in the prior art includes a buffer cylinder, a piston rod and a cartridge valve system, including a relief valve, a three-position four-way valve, a one-way valve, a throttle valve and a two-position three-way valve, as well as other valves and oil tanks, oil pumps and pipelines used therewith. Chinese patent CN104613039A discloses a hydraulic control device for a load-bearing hydraulic lifting mechanism, which is used to control the lifting and lowering of a servo oil cylinder, including a three-position four-way electromagnetic reversing valve, a two-position two-way electromagnetic throttling reversing valve, a first throttle valve, a two-position three-way electromagnetic reversing valve, a one-way sequence valve, a two-position four-way electromagnetic reversing valve and a first relief valve interconnected with the servo oil cylinder; the downward position of the servo oil cylinder is detected by a position sensor arranged on the servo oil cylinder, and the sensor device is located in the oil cylinder for a long time. Long-term use affects the accurate performance of the sensor on the one hand, and shortens the service life of the sensor on the other hand, resulting in high maintenance costs for the hydraulic system. Chinese patent CN103470552A discloses a hydraulic system with a buffer function, including a buffer cylinder, a piston rod and a cartridge valve system, wherein the piston rod is arranged in the buffer cylinder, the buffer cylinder is connected to the oil port of the cartridge valve system through an oil pipe, and a reversing valve and a one-way throttle valve are installed on the control oil circuit between the buffer cylinder and the cartridge valve system, and the reversing valve and the one-way throttle valve are arranged in parallel. The hydraulic system with a buffer function is provided with a reversing valve and a one-way throttle valve, and the reversing valve and the one-way throttle valve can control the flow rate of hydraulic oil in the buffer cylinder to achieve the purpose of buffering. Although the buffer system in the above-mentioned prior art limits the flow rate of hydraulic oil during the working process through the throttle valve, it still takes a period of time to drive the reversing valve to reverse during the return process, which affects the working efficiency of the hydraulic system. In addition, the hydraulic system has a complex structure, a large number of types and quantities of hydraulic components, a high risk of oil leakage, and a high cost. Summary of the invention

[0004] In view of the above problems, the present invention provides a hydraulic cylinder buffer system, which aims to solve the problem that in the existing hydraulic system, due to the reaction of physical impact, the cylinder will also be subjected to a reaction force, which affects the service life of the cylinder; to solve the problem that in the initial stage of the hydraulic system's oil return process, it takes a period of time to pass through the throttle valve to drive the reversing valve to reverse, affecting the working efficiency of the hydraulic system; to solve the problems of complex hydraulic system structure, large number of types and quantities of hydraulic components, high risk of oil leakage, high cost, poor overall machine stability and operating comfort.

[0005] The present invention adopts the following technical solutions to achieve the above purpose:

[0006] A hydraulic cylinder buffer system includes a two-position four-way electromagnetic reversing valve and a one-way valve group; one end of the two-position four-way electromagnetic reversing valve is connected to two pipelines, and the other end is respectively connected to the one-way valve group and the pipeline; the one-way valve group includes a first one-way valve and a second one-way valve in parallel, and a throttle valve connected in series with the second one-way valve; the first one-way valve flows toward the hydraulic cylinder, and the second one-way valve flows away from the hydraulic cylinder. One pipeline at one end of the two-position four-way electromagnetic reversing valve is opposite to the pipeline at the other end, and the other pipeline at one end of the two-position four-way electromagnetic reversing valve is opposite to the one-way valve group at the other end.

[0007] When the rodless oil chamber enters the oil, the piston rod is pushed to move to the right. When the piston rod does not reach the specified position, the two-position four-way solenoid reversing valve is in the left position, the two-position four-way solenoid reversing valve has two opposite pipelines connected, the one-way valve group is not connected to the opposite pipeline, and the oil in the rod oil chamber flows through the pipeline through the two-position four-way solenoid reversing valve to discharge oil normally; when the piston rod moves to the specified position, the two-position four-way solenoid reversing valve is in the right position, at this time, the two-position four-way solenoid reversing valve has two opposite pipelines not connected, the one-way valve group is connected to the opposite pipeline, and the oil in the rod oil chamber is discharged through the two-position four-way solenoid reversing valve, the second one-way valve, and the throttle valve in turn. The throttle valve plays a role in limiting the oil outlet speed of the rod oil chamber, that is, limiting the oil return speed of the rodless oil chamber, and reducing the movement speed of the piston rod. The designated position of the two-position four-way solenoid reversing valve can be set according to the stroke of the oil cylinder. When a buffer is required at the end of the oil cylinder stroke, the stroke switch only needs to be set within the end of the safe stroke. Then, when the oil cylinder stroke reaches the end, the throttle valve will limit the speed of the piston rod. When the piston rod continues to move to the right after deceleration and reaches the terminal in parallel, the two-position four-way solenoid reversing valve is still working in the right position. The operator manipulates the handle to make the rod oil chamber enter the oil. Then the oil will pass through the first one-way valve, the two-position four-way solenoid reversing valve, and finally enter the rod oil chamber. At this time, the throttle valve does not work, so as not to affect the speed of the oil entering the rod oil chamber. When the piston rod continues to be recovered to the designated position, the two-position four-way solenoid reversing valve is working in the left position. At this time, the oil entering the rod oil chamber no longer passes through the one-way valve, but directly enters the rod oil chamber through the opposite pipelines at both ends of the two-position four-way solenoid reversing valve.

[0008] A further technical solution is that it also includes a travel switch, which is connected to the reversing valve signal and controls the reversing of the reversing valve through the travel switch. The reversing valve is controlled by the travel switch to perform reversing work.

[0009] Its further technical solution is a hydraulic system, including the hydraulic cylinder buffer system of the above solution; also including a rod oil chamber, a rodless oil chamber, a distribution valve, an oil tank, and a pump; the rod oil chamber is connected to one end of the distribution valve, and the hydraulic cylinder buffer system is connected in series therebetween, and is opposite to the pipeline connected to the oil tank at the other end of the distribution valve; the rodless oil chamber is connected to one end of the distribution valve, and is opposite to the pump at the other end of the distribution valve; the pump is connected to the oil tank. Under working conditions, the hydraulic cylinder buffer system at both ends of the distribution valve is connected to the oil tank through pipelines to form an oil outlet path of the rod oil chamber; the rodless oil chamber at both ends of the distribution valve is connected to the pump through pipelines to form an oil return path of the rodless oil chamber.

[0010] A further technical solution is that a safety valve is provided on the pipeline connecting the pump and the oil tank.

[0011] A further technical solution is characterized in that a contact of a travel switch is provided at one end of the piston rod, and the distance between the travel switch and the contact is smaller than the stroke of the piston.

[0012] Working principle: A travel switch is set in the stroke of the oil cylinder piston rod. When the rodless oil chamber enters the oil chamber, the piston rod is pushed to move to the right. Before the contact of the piston rod reaches the travel switch, the electromagnetic reversing valve is not energized and works in the left position under the action of the spring force. The oil in the rod oil chamber is discharged normally to the oil tank through the pipeline connected at both ends of the electromagnetic reversing valve and the pipeline connected at both ends of the distribution valve. When the piston rod continues to move to the right, after the contact connects to the travel switch, the electromagnetic reversing valve is energized and works in the right position. At this time, the oil in the rod oil chamber is discharged normally through the electromagnetic reversing valve, the second one-way valve, the throttle valve, and the pipeline connected at both ends of the distribution valve, and finally returns to the oil tank. The throttle valve plays a role in limiting the oil discharge speed of the rod oil chamber, that is, reducing the movement speed of the piston rod.

[0013] Similarly: when the piston rod continues to move rightward after deceleration and reaches the terminal (the electromagnetic reversing valve is still in the right position at this time), the operator manipulates the handle to allow oil to enter the rod oil chamber, and the oil will pass through the pump, the distribution valve, the first one-way valve, the electromagnetic reversing valve, and finally enter the rod oil chamber. At this time, the throttle valve does not work, so it does not affect the speed of oil entering the rod oil chamber. When the piston rod continues to retract and touches the travel switch again, the electromagnetic reversing valve loses power and works in the left position under the action of the spring force. At this time, the oil entering the rod oil chamber no longer passes through the one-way valve, but directly enters the rod oil chamber through the pipeline connected at both ends of the electromagnetic reversing valve.

[0014] The beneficial effects of the present invention are:

[0015] 1. The hydraulic cylinder buffer system provided by the present invention improves the stability of the whole machine and the operating comfort.

[0016] 2. The hydraulic cylinder buffer system provided by the present invention reduces the physical impact of the piston on the cylinder and prolongs the service life of the cylinder.

[0017] 3. The hydraulic cylinder buffer system provided by the present invention has a simple system structure, a small number of hydraulic components, reduced oil leakage risk, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the left-position operation of the reversing valve of the hydraulic cylinder buffer system described in the present invention.

[0019] Figure 2 The present invention is a schematic structural diagram of a reversing valve in a hydraulic cylinder buffer system working in the right position.

[0020] In the figure: 1. Two-position four-way solenoid reversing valve; 2. One-way valve group; 21. First one-way valve; 22. Second one-way valve; 23. Throttle valve; 3. Travel switch; 4. Oil cylinder; 41. Rod oil chamber; 42. Rodless oil chamber; 5. Distribution valve; 6. Oil tank; 7. Pump; 8. Safety valve; 9. Contact. DETAILED DESCRIPTION

[0021] The following is combined with Figure 1 to Figure 2 The present invention is described in detail with specific embodiments.

[0022] like Figure 1 , Figure 2 As shown, it is an embodiment of the present invention, which provides a hydraulic system with hydraulic cylinder buffer, including a rod oil chamber 41, a rodless oil chamber 42, a distribution valve 5, an oil tank 6, a pump 7 and a hydraulic cylinder buffer system; its hydraulic cylinder buffer system includes a two-position four-way electromagnetic reversing valve 1 and a one-way valve group 2; one end of the two-position four-way electromagnetic reversing valve 1 is connected to two pipelines, and the other end is respectively connected to the one-way valve group 2 and the pipeline, wherein one pipeline at one end of the two-position four-way electromagnetic reversing valve 1 is opposite to the pipeline at the other end, and the other pipeline at one end of the two-position four-way electromagnetic reversing valve 1 is opposite to the one-way valve group 2 at the other end; the one-way valve group 2 includes A first one-way valve 21 and a second one-way valve 22 are connected in parallel, and a throttle valve 23 is connected in series with the second one-way valve 22; the first one-way valve 21 flows in the direction pointing to the hydraulic cylinder 4, and the second one-way valve 22 flows in the direction away from the hydraulic cylinder 4; its rod oil chamber 41 is connected to one end of the distribution valve 5, and a hydraulic cylinder buffer system is connected in series therebetween, and the hydraulic cylinder buffer system is opposite to a pipeline connected to the oil tank 6 at the other end of the distribution valve 5; the rodless oil chamber 42 is connected to one end of the distribution valve 5 through a pipeline, and the pipeline is opposite to a pipeline connected to the pump 7 at the other end of the distribution valve 5; the pump 7 is also connected to the oil tank 6; and a travel switch 3 is provided in the piston rod stroke of the cylinder 4.

[0023] Under working conditions, the hydraulic cylinder buffer system at both ends of the distribution valve 5 is connected to the oil tank 6 through pipelines, forming an oil outlet path of the rod oil chamber 41; the rodless oil chamber 42 at both ends of the distribution valve 5 is connected to the pump 7 through pipelines, forming an oil return path of the rodless oil chamber 42. Before the contact of the piston rod reaches the travel switch, the rodless oil chamber 42 enters the oil, pushing the piston rod to move to the right, and the two-position four-way electromagnetic reversing valve 1 is not energized. Under the action of the spring force, the oil in the rod oil chamber 41 is normally discharged to the oil tank 6 through the pipelines connected at both ends of the two-position four-way electromagnetic reversing valve 1 and the pipelines connected at both ends of the distribution valve 5.

[0024] When the piston rod continues to move right and touches the travel switch 3, the two-position four-way solenoid reversing valve 1 is energized and works in the right position. At this time, the oil in the rod oil chamber is discharged in sequence through the two-position four-way solenoid reversing valve 1, the second one-way valve 22, the throttle valve 23, and the pipeline connected at both ends of the distribution valve 5, and finally returns to the oil tank 6. The throttle valve 23 limits the speed at which the oil flows out of the rod oil chamber 41, that is, reduces the movement speed of the piston rod.

[0025] When the piston rod continues to move rightward after deceleration and reaches the terminal, the operator manipulates the handle to allow oil to enter the rod oil chamber 41. The oil will pass through the pump 7, the distribution valve 5, the first one-way valve 21, the two-position four-way electromagnetic reversing valve 1, and finally enter the rod oil chamber 41. Since the second one-way valve 22 is in a closed state when the rod oil chamber 41 enters the oil, the throttle valve 23 does not work, so it does not affect the speed of oil entering the rod oil chamber 41. When the piston rod continues to retract and touches the travel switch 3 again, the two-position four-way electromagnetic reversing valve 1 loses power and works in the left position under the action of the spring force. At this time, the oil entering the rod oil chamber 41 no longer passes through the one-way valve group 2, but directly enters the rod oil chamber 41 through the pipeline connected at both ends of the two-position four-way electromagnetic reversing valve 1. This embodiment only uses an oil circuit consisting of a two-position four-way electromagnetic reversing valve 1, a first one-way valve 21, a second one-way valve 22, and a throttle valve 23 to achieve the buffering function of the hydraulic cylinder 4. It has a simple structure, simple parts, and a low risk of oil leakage.

[0026] The travel switch 3 in this embodiment can be provided with a contact 9 of the travel switch 3 at one end of the piston rod, and the distance between the travel switch 3 and the contact 9 is less than the stroke of the piston; or the travel switch 3 is a distance sensor arranged in the rod cylinder 41, and is connected to the signal of the two-position four-way electromagnetic reversing valve 1. When the distance is less than the set value, the two-position four-way electromagnetic reversing valve 1 is energized, and when it is greater than the set value, the two-position four-way electromagnetic reversing valve 1 is de-energized; or the travel switch 3 is a displacement sensor arranged in the rod cylinder 41, which is used to detect the displacement of the piston rod and is connected to the signal of the two-position four-way electromagnetic reversing valve 1. When the displacement is greater than the set value, the two-position four-way electromagnetic reversing valve 1 is energized, and when it is less than the set value, the two-position four-way electromagnetic reversing valve 1 is de-energized.

[0027] Another embodiment, based on the above embodiment, provides a hydraulic system with hydraulic cylinder buffer, and also includes a safety valve 8 on the pipeline connecting the pump 7 and the oil tank 6.

[0028] The present invention provides a hydraulic cylinder buffer system and a hydraulic system with the buffer system, which improve the stability of the whole machine and the operating comfort, reduce the physical impact of the piston on the cylinder, and extend the service life of the cylinder; the system structure is simple, the types and quantities of hydraulic components are small, the risk of oil leakage is low, and the cost is low.

Claims

1. A hydraulic cylinder buffer system, characterized in that: It comprises a two-position four-way electromagnetic reversing valve (1) and a one-way valve group (2); one end of the two-position four-way electromagnetic reversing valve (1) is connected to two pipelines, and the other end is respectively connected to the one-way valve group (2) and the pipeline; the one-way valve group (2) comprises a first one-way valve (21) and a second one-way valve (22) connected in parallel, and a throttle valve (23) connected in series with the second one-way valve (22); the first one-way valve (21) flows in a direction toward the hydraulic cylinder, and the second one-way valve (22) flows in a direction away from the hydraulic cylinder; A pipeline at one end of the two-position four-way electromagnetic reversing valve (1) is arranged opposite to a pipeline at the other end, and another pipeline at one end of the two-position four-way electromagnetic reversing valve (1) is arranged opposite to a one-way valve group (2) at the other end; when the two-position four-way electromagnetic reversing valve (1) is in the left position, the pipelines at both ends of the two-position four-way electromagnetic reversing valve (1) are connected, and the one-way valve group is not connected to the corresponding pipelines; when the two-position four-way electromagnetic reversing valve (1) is in the right position, the pipelines at both ends of the two-position four-way electromagnetic reversing valve (1) are not connected, and the one-way valve group (2) is connected to the corresponding pipelines; The hydraulic cylinder buffer system further comprises a travel switch (3), wherein the travel switch (3) is connected to a signal of a two-position four-way electromagnetic reversing valve (1), and the reversing of the two-position four-way electromagnetic reversing valve (1) is controlled by the travel switch (3).

2. A hydraulic system, characterized in that: It comprises the hydraulic cylinder buffer system as claimed in claim 1; it also comprises a rod oil chamber (41), a rodless oil chamber (42), a distribution valve (5), an oil tank (6), and a pump (7); the rod oil chamber (41) contains a piston rod and is connected to one end of the distribution valve (5), and the hydraulic cylinder buffer system is connected in series therebetween, and the other end of the distribution valve (5) is connected to the oil tank (6); the rodless oil chamber (42) is connected to one end of the distribution valve (5), and the other end of the distribution valve (5) is connected to the pump (7); the pump (7) is connected to the oil tank (6).

3. A hydraulic system according to claim 2, characterized in that: A safety valve (8) is provided on the pipeline connecting the pump (7) and the oil tank (6).

4. A hydraulic system according to claim 2, characterized in that: A contact (9) of a travel switch (3) is provided at one end of the piston rod, and the distance between the travel switch (3) and the contact (9) is smaller than the stroke of the piston.

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