Ramp lift hydraulic system, method, and construction vehicle

Abstract

This invention discloses a hydraulic system, method, and vehicle for raising and lowering a loading ladder on an engineering vehicle. The system includes a hydraulic cylinder connected to a first control system for controlling the ladder's ascent and a second control system for controlling its descent. The first control system includes a first hydraulic circuit switching valve and a second hydraulic circuit switching valve. The second control system includes a third hydraulic circuit switching valve and a power unit. This invention raises the loading ladder by simultaneously energizing the first and second hydraulic circuit switching valves, causing the cylinder piston to extend. It lowers the loading ladder by energizing the power unit and the third switching valve, causing the cylinder piston to retract. This method of controlling the loading ladder's raising and lowering is versatile, flexible, energy-efficient, and highly effective.

Description

Technical Field

[0001] This invention relates to the field of engineering vehicle washing technology, specifically to a hydraulic system, method, and engineering vehicle for lifting and lowering a loading ladder. Background Technology

[0002] With the increasing demand for national infrastructure construction, and against the backdrop of environmental pollution and energy shortages, the industry and market have placed higher demands on the high efficiency, energy saving, and environmental protection performance of construction machinery. Energy saving and emission reduction technologies have become an important direction for research and development in the field of construction machinery.

[0003] Large-scale construction machinery is a crucial piece of equipment in engineering construction, and its market share continues to rise due to its high efficiency. In large mobile construction machinery, the working platform is significantly higher than the ground; therefore, a liftable loading ladder is typically installed to facilitate worker access. Since hydraulic systems have a high power density, hydraulic control is employed to reduce space occupancy and facilitate maintenance and installation. Therefore, this paper proposes a hydraulic control system for lifting loading ladders on construction vehicles, which features low cost, good versatility, flexible control methods, energy efficiency, and suitability for widespread adoption. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a simple structure and good performance.

[0005] The present invention is achieved by the following technical solution: a hydraulic system for lifting and lowering a loading ladder for engineering vehicles, including a cylinder, wherein the cylinder is connected to a first control system for controlling the lifting of the loading ladder and a second control system for controlling the lowering of the loading ladder;

[0006] The first control system includes a first oil circuit switching valve and a second oil circuit switching valve. The oil inlet of the first oil circuit switching valve is connected to the pilot oil circuit, and the oil outlet of the first oil circuit switching valve is connected to the rodless chamber of the oil cylinder. The oil inlet of the second oil circuit switching valve is connected to the oil tank, and the oil outlet of the second oil circuit switching valve is connected to the rod chamber of the oil cylinder.

[0007] The second control system includes a third oil circuit switching valve and a power unit. The oil inlet of the third oil circuit switching valve is connected to the oil tank, and the oil outlet of the third oil circuit switching valve is connected to the rodless chamber of the oil cylinder. The power unit is connected to the rod chamber of the oil cylinder through a one-way valve I.

[0008] Furthermore, the first oil circuit switching valve, the second oil circuit switching valve, and the third oil circuit switching valve are two-position three-way solenoid directional valves.

[0009] The oil inlet of the third oil circuit switching valve is connected to the oil tank through a speed regulating valve, and the oil inlet of the third oil circuit switching valve is also connected to the rod chamber of the oil cylinder through a one-way valve II.

[0010] It also includes an accumulator and several shut-off valves. The accumulator is connected to the pilot oil circuit. A second shut-off valve is provided between the accumulator and the rod chamber of the cylinder. A third shut-off valve is provided between the rodless chamber of the cylinder and the oil tank.

[0011] Both the rodless chamber and the rod chamber of the hydraulic cylinder are connected to relief valve assemblies.

[0012] The overflow valve assembly includes an overflow valve and a check valve arranged in parallel. The oil inlet of the overflow valve is connected to the oil outlet of the check valve, and the oil outlet of the check valve is connected to the oil cylinder.

[0013] The method for using a hydraulic system for raising and lowering loading ladders on engineering vehicles includes the procedures for raising and lowering the loading ladder.

[0014] The ascent of the loading ladder includes the following control steps:

[0015] S1. When the engineering vehicle starts and the boarding ladder is raised, the first oil circuit switching valve and the second oil circuit switching valve are energized simultaneously.

[0016] S2, the first oil circuit switching valve and the second oil circuit switching valve switch to the working position;

[0017] S3. The pilot oil circuit outputs to the rodless chamber of the cylinder via the first oil circuit switching valve, and the oil in the rod chamber of the cylinder is output to the oil tank via the second oil circuit switching valve.

[0018] S4, the cylinder piston rod extends and the loading ladder rises;

[0019] The descent of the boarding stairs includes the following control steps:

[0020] T1. When the engineering vehicle stops and the boarding ladder is lowered, the power unit is started and the third oil circuit switching valve is energized.

[0021] T2, the third oil circuit switching valve switches to the working position;

[0022] T3. The power unit outputs oil to the rod chamber of the cylinder. The oil in the rodless chamber of the cylinder is divided into two paths after passing through the third oil circuit switching valve. One path is output to the rod chamber of the cylinder through a check valve, and the other path returns to the oil tank through the speed control valve.

[0023] T4, the cylinder piston rod retracts and the boarding ladder descends.

[0024] In step S3, the accumulator absorbs the pressure impact during the ascent of the boarding ladder and stores energy.

[0025] When the power to the engineering vehicle is lost, the shut-off valve and the shut-off valve are opened in sequence, the accumulator releases the stored energy, the oil in the rodless chamber of the cylinder is output to the oil tank through the shut-off valve, and the oil in the rod chamber of the cylinder absorbs the oil released by the accumulator and the oil passing through the one-way valve built into the overflow valve group, so that the boarding ladder can be lowered.

[0026] An engineering vehicle includes a hydraulic system for lifting and lowering the loading ladder of the engineering vehicle and a method for using the hydraulic system for lifting and lowering the loading ladder of the engineering vehicle.

[0027] This invention has the following advantages: The hydraulic system, method, and vehicle for raising and lowering a loading ladder in engineering vehicles, as described in this invention, achieve the following: By simultaneously energizing the first and second oil circuit switching valves, the piston in the hydraulic cylinder extends, causing the loading ladder to rise; by controlling the start of the power unit and energizing the third switching valve, the piston in the hydraulic cylinder retracts, causing the loading ladder to descend; simultaneously, relying on the weight of the loading ladder, a portion of the hydraulic fluid in the large chamber of the hydraulic cylinder enters the small chamber through a one-way valve, achieving flow regeneration, reducing the installed power of the power unit, and thus reducing costs and saving energy. The method of controlling the raising and lowering of the loading ladder in this invention has good versatility, flexible control, and is energy-efficient. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the hydraulic principle of the present invention;

[0029] Figure 2 This is a schematic diagram of the ascending action of the boarding ladder of the present invention;

[0030] Figure 3 This is a schematic diagram of the descent action of the boarding ladder according to the present invention.

[0031] In the diagram: 1. Power unit, 2. Check valve I, 3. First shut-off valve, 4. Speed ​​control valve, 5. Check valve II, 6. Third oil circuit switching valve, 7. First oil circuit switching valve, 8. Second oil circuit switching valve, 9. Accumulator, 10. Second shut-off valve, 11. Third shut-off valve, 12. Overflow valve assembly, 13. Oil cylinder. Detailed Implementation

[0032] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0033] like Figures 1 to 3The hydraulic system for raising and lowering a loading ladder for engineering vehicles, as shown, includes a cylinder 13. The cylinder 13 is connected to a first control system for controlling the upward movement of the loading ladder and a second control system for controlling its downward movement. The cylinder of this invention is connected to two control systems, which are used to control the raising and lowering of the loading ladder respectively. When the first system is in use, oil enters the rodless chamber of the cylinder and exits the rod chamber, causing the piston to extend and thus raising the loading ladder. When the second system is in use, oil enters the rod chamber of the cylinder and exits the rodless chamber, causing the piston to retract and thus lowering the loading ladder. Simultaneously, relying on the weight of the loading ladder, some oil from the rodless chamber of the cylinder enters the rod chamber, achieving flow regeneration, reducing the installed power of the power unit, and thus achieving cost reduction and energy saving.

[0034] like Figures 1 to 3 The hydraulic system for lifting and lowering a loading ladder for engineering vehicles shown includes a first control system comprising a first oil circuit switching valve 7 and a second oil circuit switching valve 8. The inlet of the first oil circuit switching valve 7 is connected to a pilot oil circuit, and the outlet of the first oil circuit switching valve 7 is connected to the rodless chamber of the cylinder 13. The inlet of the second oil circuit switching valve 8 is connected to an oil tank, and the outlet of the second oil circuit switching valve 8 is connected to the rod chamber of the cylinder 13. The first control system of this invention mainly includes a first oil circuit switching valve and a second oil circuit switching valve. The inlet P of the first oil circuit switching valve is connected to the pilot oil circuit, and the outlet B is connected to the A port of the cylinder. The outlet B of the second oil circuit switching valve is connected to the B port of the cylinder, and the inlet P is connected to the oil tank. When the first control system is working, it controls the first and second oil circuit switching valves to be simultaneously energized and switched to a second working position, controlling the cylinder piston to extend and thus raising the loading ladder.

[0035] like Figures 1 to 3 The hydraulic system for lifting and lowering the loading ladder of engineering vehicles shown includes a second control system, comprising a third oil circuit switching valve 6 and a power unit 1. The oil inlet of the third oil circuit switching valve 6 is connected to an oil tank, and the oil outlet of the third oil circuit switching valve 6 is connected to the rodless chamber of the cylinder 13. The oil inlet of the third oil circuit switching valve 6 is connected to the oil tank via a speed regulating valve 4, and the oil inlet of the third oil circuit switching valve 6 is also connected to the rod chamber of the cylinder 13 via a one-way valve II 5. The power unit 1 is connected to the rod chamber of the cylinder 13 via a one-way valve I 2. The second control system of the present invention mainly includes a third oil circuit switching valve and a power unit. The oil outlet B of the third oil circuit switching valve is connected to the oil port A of the oil cylinder, and the oil inlet P is connected to the oil inlet of the one-way valve II and the oil inlet of the speed regulating valve. The power unit is connected to the oil inlet of the one-way valve I, and the oil outlet of the one-way valve I is connected to the oil port B of the oil cylinder. When the second control system is working, it controls the power unit to start and the third switching valve to be energized to the second working position, controls the piston of the oil cylinder to retract, realizes the descent of the loading ladder, and at the same time, relying on the weight of the loading ladder, part of the oil in the large chamber of the oil cylinder enters the small chamber of the oil cylinder through the one-way valve II, realizes flow regeneration, reduces the installed power of the power unit, and achieves the purpose of reducing costs and saving energy.

[0036] like Figures 1 to 3 The hydraulic system for lifting and lowering the loading ladder of engineering vehicles shown is described, wherein the first oil circuit switching valve 7, the second oil circuit switching valve 8, and the third oil circuit switching valve 6 are two-position three-way solenoid directional valves. The three oil circuit switching valves of this invention have the same structure; they are all two-position three-way solenoid directional valves, and their working positions are controlled by energization and de-energization to achieve the connection and disconnection of the oil inlet and outlet.

[0037] like Figures 1 to 3 The hydraulic system for lifting and lowering the loading ladder of an engineering vehicle, as shown, also includes an accumulator 9 and several shut-off valves. The accumulator 9 is connected to a pilot oil circuit. A second shut-off valve 10 is provided between the accumulator 9 and the rod chamber of the cylinder 13, and a third shut-off valve 11 is provided between the rodless chamber of the cylinder 13 and the oil tank. A shut-off valve is provided between the inlet of the accumulator and the inlet P of the first oil circuit switching valve, and between the inlet oil circuit of the accumulator and the outlet B of the second oil circuit switching valve. A first shut-off valve 3 is also provided between the inlet oil circuit of the accumulator and the oil tank. The accumulator is used to absorb pressure shocks during the ascent of the loading ladder and to store energy.

[0038] like Figures 1 to 3 The hydraulic system for lifting and lowering the loading ladder of engineering vehicles shown in the diagram has a relief valve assembly 12 connected to both the rodless and rod-type chambers of the cylinder 13. The relief valve assembly 12 includes a relief valve and a check valve arranged in parallel. The inlet of the relief valve is connected to the outlet of the check valve, and the outlet of the check valve is connected to the cylinder 13. The relief valve assembly of this invention incorporates a relief valve and a check valve. The inlet of the relief valve is connected to the outlet channel of the check valve, and the outlet of the relief valve is connected to the inlet channel of the check valve. The outlet of the relief valve assembly is connected to the oil tank. The cylinder's A port and B port are respectively connected to the outlets of the two check valves built into the relief valve assembly. A shut-off valve is installed between the cylinder's A port and the oil tank. The check valve built into the relief valve assembly has a replenishing function.

[0039] The specific usage method of the hydraulic system for lifting and lowering loading stairs of engineering vehicles is as follows:

[0040] like Figure 2 As shown, when the engineering vehicle starts and the loading ladder is controlled to rise, the first oil circuit switching valve 7 and the second oil circuit switching valve 8 are simultaneously energized and switched to the second position. The pilot oil circuit is output to the large chamber of the hydraulic cylinder 13 through the second position of the first oil circuit switching valve 7, and the oil in the small chamber of the hydraulic cylinder 13 is output to the oil tank through the second position of the second oil circuit switching valve 8. The above steps realize the extension of the piston rod of the hydraulic cylinder 13 and the rise of the loading ladder. During this process, the accumulator 9 absorbs the pressure impact during the rise of the loading ladder and stores energy.

[0041] like Figure 3As shown, when the engineering vehicle stops and the loading ladder is lowered, the power unit 1 is started, and the third oil circuit switching valve 6 is energized and switched to the second position. The oil output from the power unit 1 flows through the check valve to the small chamber of the cylinder 13, and the oil in the large chamber of the cylinder 13 flows out through the second position of the third oil circuit switching valve 6 and is divided into two paths. One path is output through the check valve 5 to the small chamber of the cylinder 13, and the other path returns to the oil tank through the speed regulating valve 4. The above steps realize the retraction of the piston rod of the cylinder 13 and the descent of the loading ladder.

[0042] During the descent of the boarding ladder, the boarding ladder descends by its own weight. The oil in the large chamber of the hydraulic cylinder 13 is output to the small chamber of the hydraulic cylinder 13 through the third oil circuit switching valve 6 and the one-way valve 5, forming a regeneration circuit for the small chamber of the hydraulic cylinder. The power unit 1 outputs oil to the small chamber of the hydraulic cylinder 13 to prevent the small chamber of the hydraulic cylinder 13 from sucking in air. At the same time, the speed regulating valve 4 can adjust the descent speed of the boarding ladder to achieve a stable descent of the boarding ladder.

[0043] When the power to the engineering vehicle is lost, the shut-off valves 10 and 11 can be opened in sequence, the accumulator 9 releases the stored energy, the oil in the rodless chamber of the cylinder 13 is output to the oil tank through the shut-off valve 11, and the oil in the rod chamber of the cylinder 13 absorbs the oil released by the accumulator and the oil through the one-way valve built into the overflow valve group 12, so that the boarding ladder can be lowered.

[0044] An engineering vehicle includes the aforementioned hydraulic system for lifting and lowering the loading ladder of the engineering vehicle and a method for using the hydraulic system for lifting and lowering the loading ladder of the engineering vehicle.

[0045] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic system for lifting and lowering loading stairs for engineering vehicles, characterized in that: Includes a hydraulic cylinder (13), which is connected to a first control system for controlling the boarding ladder to rise and a second control system for controlling the boarding ladder to fall; The first control system includes a first oil circuit switching valve (7) and a second oil circuit switching valve (8). The oil inlet of the first oil circuit switching valve (7) is connected to the pilot oil circuit, and the oil outlet of the first oil circuit switching valve (7) is connected to the rodless chamber of the oil cylinder (13). The oil inlet of the second oil circuit switching valve (8) is connected to the oil tank, and the oil outlet of the second oil circuit switching valve (8) is connected to the rod chamber of the oil cylinder (13). The second control system includes a third oil circuit switching valve (6) and a power unit (1). The oil inlet of the third oil circuit switching valve (6) is connected to the oil tank, and the oil outlet of the third oil circuit switching valve (6) is connected to the rodless chamber of the oil cylinder (13). The power unit (1) is connected to the rod chamber of the oil cylinder (13) through a one-way valve I (2). The oil inlet of the third oil circuit switching valve (6) is connected to the oil tank through the speed regulating valve (4), and the oil inlet of the third oil circuit switching valve (6) is also connected to the rod chamber of the oil cylinder (13) through the one-way valve II (5). When the boarding ladder descends, the power unit (1) outputs oil to the rod chamber of the cylinder (13). The oil in the rodless chamber of the cylinder (13) is divided into two paths after passing through the third oil circuit switching valve (6). One path is output to the rod chamber of the cylinder (13) through the check valve (5), and the other path returns to the oil tank through the speed regulating valve (4).

2. The hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 1, characterized in that: The first oil circuit switching valve (7), the second oil circuit switching valve (8) and the third oil circuit switching valve (6) are two-position three-way solenoid directional valves.

3. The hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 1, characterized in that: It also includes an accumulator (9) and several shut-off valves. The accumulator (9) is connected to the pilot oil circuit. A second shut-off valve (10) is provided between the accumulator (9) and the rod chamber of the cylinder (13). A third shut-off valve (11) is provided between the rodless chamber of the cylinder (13) and the oil tank.

4. The hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 1, characterized in that: Both the rodless chamber and the rod chamber of the hydraulic cylinder (13) are connected to an overflow valve assembly (12).

5. The hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 4, characterized in that: The overflow valve assembly (12) includes an overflow valve and a check valve arranged in parallel. The oil inlet of the overflow valve is connected to the oil outlet of the check valve, and the oil outlet of the check valve is connected to the oil cylinder (13).

6. A method for using a hydraulic system for lifting and lowering a loading ladder for engineering vehicles, comprising the hydraulic system for lifting and lowering a loading ladder for engineering vehicles as described in any one of claims 1-5, characterized in that: This includes the ascending and descending of the boarding stairs. The ascent of the loading ladder includes the following control steps: S1. When the engineering vehicle starts and the boarding ladder is raised, the first oil circuit switching valve (7) and the second oil circuit switching valve (8) are energized at the same time. S2, the first oil circuit switching valve (7) and the second oil circuit switching valve (8) switch to the working position; S3. The pilot oil circuit outputs to the rodless chamber of the cylinder (13) via the first oil circuit switching valve (7), and the oil in the rod chamber of the cylinder (13) is output to the oil tank via the second oil circuit switching valve (8). S4, the piston rod of the hydraulic cylinder (13) extends and the loading ladder rises; The descent of the boarding stairs includes the following control steps: T1. When the engineering vehicle stops and the boarding ladder is lowered, the power unit (1) is started and the third oil circuit switching valve (6) is energized. T2, the third oil circuit switching valve (6) switches the working position; T3, the power unit (1) outputs oil to the rod chamber of the cylinder (13). The oil in the rodless chamber of the cylinder (13) is divided into two paths after passing through the third oil circuit switching valve (6). One path is output to the rod chamber of the cylinder (13) through the check valve (5), and the other path returns to the oil tank through the speed regulating valve (4). T4, the piston rod of the hydraulic cylinder (13) retracts and the boarding ladder descends.

7. The method of using the hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 6, characterized in that: In step S3, the accumulator (9) absorbs the pressure impact during the ascent of the boarding ladder and stores energy.

8. The method of using the hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in claim 6, characterized in that: When the engineering vehicle loses power, the shut-off valve (10) and shut-off valve (11) are opened in sequence, the accumulator (9) releases the stored energy, the oil in the rodless chamber of the cylinder (13) is output to the oil tank through the shut-off valve (11), and the rod chamber of the cylinder (13) absorbs the oil released by the accumulator and the oil through the one-way valve built into the overflow valve group (12), so that the boarding ladder can be lowered.

9. An engineering vehicle, characterized in that: The hydraulic system for lifting and lowering the loading ladder of engineering vehicles, as described in any one of claims 1-5.

10. An engineering vehicle, characterized in that: The method of using the hydraulic system for lifting and lowering the loading ladder of engineering vehicles as described in any one of claims 6-8.

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