Unloading valve group and erecting hydraulic cylinder

Abstract

This invention discloses a load relief valve assembly and a lifting hydraulic cylinder. The load relief valve assembly includes a throttle valve, a solenoid ball valve, a damper, a hydraulic control logic valve, and a load relief channel. The inlet of the throttle valve is connected to the rodless chamber port, and the outlet of the throttle valve is connected to two branch oil circuits in parallel. One oil circuit is directly connected to the inlet of the solenoid ball valve and the third port of the hydraulic control logic valve, and the other oil circuit is connected to the first port of the hydraulic control logic valve through the damper. The outlet of the solenoid ball valve and the second port of the hydraulic control logic valve are both connected to the drain port through the load relief channel. The throttle valve, the solenoid ball valve, and their respective oil circuits constitute the main load relief path, while the throttle valve, the damper, the hydraulic control logic valve, and their respective oil circuits constitute the high-temperature load relief path. The lifting hydraulic cylinder includes this load relief valve assembly. Through the above method, this invention, by integrating the load relief valve assembly, only requires initial pressure relief after lifting to the correct position, and subsequently automatically achieves overpressure relief. The entire process is simple to control, highly reliable, and ensures that the hydraulic cylinder is reliably locked by the steel ball lock.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and in particular to a load relief valve assembly and a lifting hydraulic cylinder. Background Technology

[0002] Currently, in hydraulic lifting systems, the lifting hydraulic cylinder acts as the actuator. It drives the piston rod to extend by supplying high-pressure oil to the rodless chamber, thereby achieving the lifting action. After the load is lifted into position, a mechanical locking mechanism is usually installed in the lifting hydraulic cylinder to maintain the long-term stable posture of the load and prevent the load from unexpectedly falling back due to leakage or external load fluctuations.

[0003] Currently, hydraulic cylinders with mechanical locking mechanisms are widely used in hydraulic lifting systems. Among them, the ball-locking cylinder is a typical locking type of hydraulic cylinder. This type of cylinder uses a ball-locking mechanism to achieve mechanical locking after positioning. Due to clearances during manufacturing and assembly, if the equipment is left idle for a long time after the cylinder is positioned and locked, and the ambient temperature varies greatly between day and night, the hydraulic oil inside the cylinder will expand due to the increased temperature. This causes the piston of the hydraulic cylinder to shift within the ball-locking gap, thereby changing the lifting angle of the equipment.

[0004] In high-precision applications such as radar, deviations in lifting accuracy will directly affect combat performance; in severe cases, if the temperature is too high and the oil expansion is too large, the piston may completely disengage from the steel ball lock, causing safety accidents such as equipment falling.

[0005] To address the aforementioned issues, a common approach is to integrate an unloading valve into the large chamber of the hydraulic cylinder. When the high-temperature hydraulic oil in the large chamber expands due to heat and its pressure rises to a set value, the unloading valve automatically opens, discharging the high-pressure oil and preventing the cylinder from disengaging. However, this method limits the cylinder's working pressure; the working pressure must not exceed the unloading valve's set pressure, otherwise, normal lifting operations will be affected. Therefore, this method only provides thermal expansion protection under ultra-high pressure conditions, and it cannot prevent the piston from moving slightly due to oil expansion under low-pressure conditions.

[0006] Another approach is to introduce a control program, using a pressure sensor in conjunction with an unloading valve for automatic control. Specifically, during the erection and holding phase, the pressure sensor monitors the pressure in the large chamber of the hydraulic cylinder in real time. When the pressure exceeds a set value, the unloading valve is automatically opened to release pressure. While introducing a control program can effectively solve the problem, the control structure is complex, and the reliability of precision electronic components such as pressure sensors is low under harsh operating conditions, making it difficult to meet the requirements for long-term stable operation. Summary of the Invention

[0007] The main technical problem solved by this invention is to provide a relief valve assembly and a lifting hydraulic cylinder. By integrating the relief valve assembly, the initial pressure relief can be completed by energizing the solenoid ball valve only once after the cylinder is lifted into position. Subsequently, overpressure relief can be automatically achieved. The whole process is simple to control, highly reliable, and ensures that the hydraulic cylinder is reliably locked by the steel ball lock.

[0008] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is to provide a relief valve assembly, including a throttle valve, a solenoid ball valve, a damper, a hydraulically controlled logic valve, and a relief channel. The inlet of the throttle valve is connected to the rodless chamber port of the hydraulic cylinder. The outlet of the throttle valve has two parallel branch oil circuits. One circuit directly connects to the inlet of the solenoid ball valve and the third port of the hydraulic control logic valve. The other circuit connects to the first port of the hydraulic control logic valve via the damper. The outlet of the solenoid ball valve and the second port of the hydraulic control logic valve are both connected to the drain port via a relief channel. The throttle valve, the solenoid ball valve, and their respective oil circuits constitute the main relief path, while the throttle valve, damper, hydraulic control logic valve, and their respective oil circuits constitute the high-temperature relief path. Through the main relief path and the high-temperature relief path, the high-pressure oil in the rodless chamber can be discharged to the drain port. After the relief action is completed, the oil pressure in the rodless chamber drops below the unlocking pressure of the steel ball lock and remains below this pressure value throughout the subsequent process. The hydraulic cylinder is locked by the steel ball lock.

[0009] In a preferred embodiment of the present invention, the throttle valve is a two-position two-way throttle valve.

[0010] In a preferred embodiment of the present invention, the damper is a threaded fixed throttling damper. The damper is used to limit the flow rate to the first port of the hydraulic control logic valve, generate a pressure difference between the third port and the first port, close the hydraulic control logic valve, realize the lifting of the mast, and avoid affecting the normal erection operation; when the lifting is in place, the solenoid ball valve is energized and opens, and the rodless chamber of the erection hydraulic cylinder is depressurized. At this time, the damper is used to limit the flow rate to the solenoid ball valve to prevent excessive pressure relief.

[0011] In a preferred embodiment of the present invention, the throttling orifice diameter of the damper is 0.3-0.8 mm.

[0012] In a preferred embodiment of the present invention, the hydraulic control logic valve is a pilot-operated closed, spring-biased normally open type logic valve. The cooperation between the hydraulic control logic valve and the solenoid ball valve realizes pressure release. After pressure relief, the hydraulic control logic valve remains in a normally open state and will not drive the load due to changes in oil temperature, ensuring that the facet angle does not change due to temperature variations.

[0013] In a preferred embodiment of the present invention, the electromagnetic ball valve is a normally closed two-position two-way electromagnetic valve.

[0014] In a preferred embodiment of the present invention, a spring for pushing the valve core is provided on the side of the hydraulic control logic valve near the third oil port, and the hydraulic control logic valve has a cut-off working position and a conduction working position. When the electromagnetic ball valve is de-energized, the third oil port is shut off, its pressure is greater than the pressure of the first oil port, and it pushes the valve core to overcome the spring force and switch to the shut-off working position, and the first oil port and the second oil port are shut off. When the electromagnetic ball valve is energized, the third oil port is connected to the drain port through the electromagnetic ball valve, causing the valve core to switch to the conducting working position under the action of the spring force, and the first oil port and the second oil port are connected.

[0015] In a preferred embodiment of the present invention, the oil outlet of the electromagnetic ball valve and the second oil port of the hydraulic control logic valve are connected in parallel and then connected to the unloading channel together.

[0016] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is: to provide a lifting hydraulic cylinder, including a cylinder body, a piston and piston rod disposed in the cylinder body, and the unloading valve assembly, wherein the piston and piston rod divide the inner cavity of the cylinder body into a rodless chamber and a rod chamber, the oil inlet of the unloading valve assembly is connected to the oil port of the rodless chamber, and the oil outlet of the unloading valve assembly is connected to the oil drain port through the unloading channel.

[0017] In a preferred embodiment of the present invention, a balance valve is further included. The balance valve is located on the oil line between the main oil supply port and the rodless chamber oil port, and is used to maintain the load when the hydraulic cylinder is not in the terminal steel ball locking position.

[0018] In a preferred embodiment of the present invention, the balancing valve is an externally controlled balancing valve.

[0019] The beneficial effects of this invention are: The unloading valve assembly does not affect the normal erection of the hydraulic cylinder, allowing the hydraulic cylinder to work reliably under any working pressure. After erection, only one energization operation of the solenoid ball valve is required to complete the initial pressure relief, and subsequent overpressure unloading can be automatically achieved. The entire control process does not require the installation of pressure sensors, the acquisition of pressure signals, or the adjustment of pressure. It only relies on the cooperation of the hydraulic control logic valve and the solenoid ball valve, which is simple to control and highly reliable. After the unloading valve assembly is integrated, the hydraulic cylinder can be reliably locked by the steel ball lock, and there will be no problem of the steel ball lock being disengaged due to high pressure or changes in oil temperature, or plastic deformation caused by thermal expansion of the oil cylinder. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic diagram of a preferred embodiment of the unloading valve assembly of the present invention; The components in the attached diagram are labeled as follows: 1. Balance valve, 2. Damper, 3. Hydraulic logic valve, 4. Throttle valve, 5. Solenoid ball valve, 6. Unloading channel, 7. Cylinder body, 8. Piston rod, 9. Rodless chamber, 10. Rod chamber. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] Please see Figure 1 The present invention provides a preferred embodiment of a relief valve assembly, which includes a throttle valve 4, a solenoid ball valve 5, a damper 2, a hydraulic logic valve 3, and a relief channel 6.

[0024] The connection relationships of the above valves are as follows: The inlet of the throttle valve 4 is connected to the rodless chamber port Aʹ of the hydraulic cylinder, and the outlet of the throttle valve 4 is connected in parallel to two branch oil circuits: One oil circuit is directly connected to the oil inlet of the solenoid ball valve 5 and the third oil port of the hydraulic control logic valve 3, while the other oil circuit is connected to the first oil port of the hydraulic control logic valve 3 via the damper 2. The oil outlet of the electromagnetic ball valve 5 and the second oil port of the hydraulic logic valve 3 are connected in parallel and then connected to the unloading channel 6, and then connected to the drain port T1.

[0025] Among them, throttle valve 4, solenoid ball valve 5 and their respective oil circuits constitute the main load relief path, while throttle valve 4, damper 2, hydraulic control logic valve 3 and their respective oil circuits constitute the high-temperature load relief path.

[0026] A balance valve 1 is also provided in the oil line between the main oil supply port A and the rodless chamber oil port Aʹ. The balance valve 1 is used to maintain the load when the hydraulic cylinder is not in the terminal steel ball locking position, to prevent the load from falling accidentally.

[0027] Furthermore, the throttle valve 4 is a two-position two-way throttle valve. In this embodiment, the NFBC-LCN type is preferred.

[0028] Furthermore, damper 2 is a threaded fixed throttling damper with a throttling orifice diameter of 0.3-0.8mm. In this embodiment, the preferred type is M6×1-7-φ0.5-CS (throttling orifice diameter 0.5mm).

[0029] Furthermore, the hydraulic control logic valve 3 is a pilot-operated, spring-biased normally open type logic valve, which has a spring on the side near the third oil port for pushing the valve core. In this embodiment, the hydraulic control logic valve 3 is preferably of type LODO-XDN.

[0030] Furthermore, the solenoid ball valve 5 is a normally closed two-position two-way solenoid valve, which opens when energized and closes when de-energized, cooperating with the hydraulic control logic valve 3 to ensure the operation of the two unloading paths. In this embodiment, the LSV6-08-2NCSP-M-2ER type is preferred.

[0031] The hydraulic control logic valve 3 has a cut-off working position and a conducting working position, and the energized state of the solenoid ball valve 5 determines different unloading paths: When the electromagnetic ball valve 5 is de-energized, the third oil port and the drain port T1 are cut off. The pressure of the third oil port is greater than that of the first oil port, and the valve core is pushed to overcome the spring force and switch to the cut-off working position. The first oil port and the second oil port are cut off, the unloading channel 6 is closed, and the erection action is carried out normally. When the electromagnetic ball valve 5 is energized, the third oil port is connected to the drain port T1 through the electromagnetic ball valve 5. At this time, the pressure at the third oil port of the hydraulic logic valve 3 drops, causing the valve core to switch to the conducting working position under the action of the spring force. The first oil port is connected to the second oil port, and the high-pressure oil in the rodless chamber 9 is discharged through the unloading valve group.

[0032] Furthermore, the balancing valve 1 is an externally controlled balancing valve. In this embodiment, the CBBA-LHN type is preferred.

[0033] The present invention also provides a preferred embodiment of an erecting hydraulic cylinder, which includes a cylinder body 7, a piston and piston rod 8 disposed within the cylinder body 7, and the aforementioned unloading valve assembly.

[0034] The piston and piston rod 8 divide the inner cavity of the cylinder 7 into a rodless chamber 9 and a rod chamber 10. The oil inlet of the unloading valve assembly is connected to the oil port Aʹ of the rodless chamber, and the oil outlet of the unloading valve assembly is connected to the oil drain port T1 through the unloading channel 6.

[0035] The operation process of the unloading valve assembly of the present invention is as follows: During normal erection: High-pressure oil supplied by the main oil supply port A flows into the rodless chamber 9 of the hydraulic cylinder through the balance valve 1, pushing the piston rod 8 to extend and driving the load to stand upright; high-pressure oil in the rod chamber 10 of the hydraulic cylinder flows back to the oil tank through the rod chamber oil port Bʹ. During this process, the electromagnetic ball valve 5 is in a de-energized and closed state, the oil inlet of the throttle valve 4 of the unloading valve group is connected to the oil port Aʹ of the rodless chamber, and the high pressure oil of the rodless chamber 9 is divided into two paths after passing through the throttle valve 4: one path flows directly to the third oil port of the hydraulic logic valve 3, and the other path flows through the damper 2 to the first oil port of the hydraulic logic valve 3. Because the solenoid ball valve 5 is closed, the third oil port of the hydraulic control logic valve 3 is closed. The high-pressure oil at the third oil port acts on the shut-off chamber of the hydraulic control logic valve 3. When the pressure is greater than the sum of the pressure at the first oil port of the hydraulic control logic valve 3 and the spring force, the hydraulic control logic valve 3 is in the shut-off chamber and remains closed. The oil in the rodless chamber 9 cannot leak through the unloading valve group, and the erection action proceeds normally.

[0036] Main unloading path after erection: After being erected into position, the solenoid ball valve 5 is energized and opened, and the high-pressure oil in the rodless chamber 9 enters the throttle valve 4. After being throttled by the throttle valve 4, it flows directly to the oil inlet of the solenoid ball valve 5, and then flows into the unloading channel 6 and the drain port T1 after passing through the oil outlet of the solenoid ball valve 5, and finally flows back to the oil tank. This path is the main unloading path, realizing the rapid pressure relief of the rodless chamber.

[0037] High-temperature load relief path after erection: When the temperature of the high-pressure oil rises, the pressure in the hydraulic cylinder and oil circuit increases, and the pressure is released through the high-temperature unloading path: When the solenoid ball valve 5 is energized and opens, the third oil port of the hydraulic control logic valve 3 is connected to the drain port T1 through the solenoid ball valve 5. As a result, the pressure at the third oil port decreases, and the hydraulic control logic valve 3 opens under the action of the spring force. At this time, the high pressure oil in the rodless chamber is throttled by the throttle valve 4 and flows into the first oil port of the hydraulic control logic valve 3 through the damper 2. Then it flows into the unloading channel and the drain port through the second oil port and finally flows back to the oil tank, realizing continuous pressure relief under high temperature conditions. This path is the high temperature unloading path.

[0038] During the high-temperature unloading process, since the hydraulic control logic valve 3 always remains in the normally open pressure relief state, even if the temperature change causes the hydraulic oil volume to change, the pressure in the rodless chamber 9 can be released in time through this high-temperature unloading path, and the pressure will not accumulate due to the thermal expansion of the oil, ensuring that the face angle will not change due to the oil temperature.

[0039] The high-pressure oil in the rodless chamber can be discharged to the drain port through the main unloading path and the high-temperature unloading path. After the unloading action is completed, the oil pressure in the rodless chamber drops to less than the unlocking pressure of the steel ball lock, and remains below this pressure value in the subsequent process. The hydraulic cylinder is locked by the steel ball lock.

[0040] The function of the unloading valve assembly is to release the high-pressure oil in the rodless chamber, so that the pressure inside the cylinder is less than the unlocking pressure of the steel ball lock. The hydraulic cylinder can then be reliably locked by the steel ball lock, and there will be no problem of the steel ball lock coming off due to high pressure or changes in oil temperature, or plastic deformation caused by thermal expansion of the cylinder.

[0041] In this embodiment, the erecting hydraulic cylinder integrates the above-mentioned unloading valve group. After the cylinder is erected in place, the main unloading path can be opened by energizing the solenoid ball valve 5 to achieve rapid pressure relief of the rodless chamber. Under high temperature conditions, continuous pressure release can be achieved through the high temperature unloading path of the hydraulic control logic valve 3 and the damper 2. After the unloading is completed, the pressure of the rodless chamber 9 drops to less than the unlocking pressure of the steel ball lock, and the steel ball lock achieves reliable locking.

[0042] During normal erection, the unloading valve group remains closed, which does not affect the erection action of the hydraulic cylinder. After the erection is in place, only one energization operation of the solenoid ball valve is required to complete the initial pressure relief. Subsequently, when the pressure in the rodless chamber exceeds the safe value due to temperature rise, the overpressure unloading action can be automatically completed. The entire control process does not require the setting of a pressure sensor, the collection of pressure signals, or the adjustment of pressure. Adaptive unloading control can be achieved solely by the cooperation of the hydraulic logic valve and the solenoid ball valve. The control is simple and highly reliable.

[0043] The beneficial effects of the unloading valve assembly and the erecting hydraulic cylinder of the present invention are: The unloading valve assembly remains closed during normal erection, which does not affect the normal erection action of the hydraulic cylinder and allows the hydraulic cylinder to work reliably under any working pressure. After being erected into position, the electromagnetic ball valve only needs to be energized once to complete the initial pressure relief. When the pressure in the rodless chamber exceeds the safe value due to the temperature rise, the high-temperature relief path is automatically opened, automatically draining the heated and expanded oil, and automatically completing the overpressure relief action. The entire control process requires no pressure sensor, no pressure signal acquisition or pressure adjustment. Adaptive unloading control can be achieved solely through the cooperation of hydraulic logic valves and solenoid ball valves. The control is simple and highly reliable. After integrating the unloading valve assembly, the hydraulic cylinder has the functions of rapid pressure relief, high-temperature adaptive unloading, and reliable locking.

[0044] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A load relief valve assembly, characterized in that, include: Throttling valve (4), solenoid ball valve (5), damper (2), hydraulic logic valve (3) and unloading channel (6). The inlet of the throttle valve (4) is connected to the oil port of the rodless chamber (9) of the hydraulic cylinder. The outlet of the throttle valve (4) is connected to two branch oil circuits in parallel. One oil circuit is directly connected to the inlet of the solenoid ball valve (5) and the third oil port of the hydraulic control logic valve (3). The other oil circuit is connected to the first oil port of the hydraulic control logic valve (3) through the damper (2). The outlet of the solenoid ball valve (5) and the second oil port of the hydraulic control logic valve (3) are both connected to the drain port through the unloading channel (6). The throttle valve (4), the solenoid ball valve (5) and their respective oil circuits constitute the main load relief path, and the throttle valve (4), the damper (2), the hydraulic logic valve (3) and their respective oil circuits constitute the high-temperature load relief path.

2. The unloading valve assembly according to claim 1, characterized in that, The throttle valve (4) is a two-position two-way throttle valve.

3. The unloading valve assembly according to claim 1, characterized in that, The damper (2) is a threaded fixed throttling damper.

4. The unloading valve assembly according to claim 3, characterized in that, The throttling orifice diameter of the damper (2) is 0.3-0.8 mm.

5. The unloading valve assembly according to claim 1, characterized in that, The hydraulic control logic valve (3) is a pilot-operated closed, spring-biased normally open type logic valve.

6. The unloading valve assembly according to claim 1, characterized in that, The solenoid ball valve (5) is a normally closed two-position two-way solenoid valve.

7. The unloading valve assembly according to claim 1, characterized in that, The hydraulic control logic valve (3) has a spring for pushing the valve core on the side near the third oil port. The hydraulic control logic valve (3) has a cut-off working position and a conduction working position. When the electromagnetic ball valve (5) is de-energized, the third oil port is shut off, its pressure is greater than that of the first oil port, and it pushes the valve core to overcome the spring force and switch to the shut-off working position, and the first oil port and the second oil port are shut off. When the electromagnetic ball valve (5) is energized, the third oil port is connected to the drain port through the electromagnetic ball valve (5), so that the valve core is switched to the conducting working position under the action of the spring force, and the first oil port is connected to the second oil port.

8. A hydraulic cylinder for erecting, characterized in that, include: The cylinder body, the piston and piston rod disposed in the cylinder body, and the unloading valve assembly as described in any one of claims 1-7, wherein the piston and piston rod divide the inner cavity of the cylinder body into a rodless chamber (9) and a rod chamber (10), the oil inlet of the unloading valve assembly is connected to the oil port of the rodless chamber (9), and the oil outlet of the unloading valve assembly is connected to the oil drain port through the unloading channel (6).

9. The erecting hydraulic cylinder according to claim 8, characterized in that, It also includes a balance valve (1), which is located on the oil line between the main oil supply port and the oil port of the rodless chamber (9).

10. The erecting hydraulic cylinder according to claim 9, characterized in that, The balancing valve (1) is an externally controlled balancing valve.

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