Hydraulic system and hydraulic device

Abstract

The utility model relates to a hydraulic technology field, concretely relates to a kind of hydraulic system and hydraulic device.A kind of hydraulic system, for the single double-acting switching of lifting cylinder, comprising: big cavity oil circuit, including big cavity oil inlet oil circuit and big cavity oil return oil circuit, all with the big cavity of lifting cylinder intercommunication, the lifting valve of control on-off is arranged on the big cavity oil inlet oil circuit, the down valve of control on-off is arranged on the big cavity oil return oil circuit;Small cavity oil circuit, with the small cavity of lifting cylinder intercommunication;Switching valve, control the oil inlet of big cavity oil inlet oil circuit and the oil inlet and outlet of small cavity oil circuit;Unloading oil circuit, in parallel in big cavity oil inlet oil circuit, unloading valve is arranged on the unloading oil circuit, the unloading valve is opened and closed under the pressure of oil inlet and outlet pressure of lifting valve.Solved the technical problem that hydraulic system in prior art cannot have single double-acting, poor applicability.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology, specifically to a hydraulic system and hydraulic device. Background Technology

[0002] In the tractor industry, if a single-acting hydraulic cylinder is used for the lifting device, the lifting device relies solely on gravity to descend without hydraulic oil drive. This process is more energy-efficient, but it suffers from low downward pressure and slow speed. However, the performance of a single-acting hydraulic cylinder lifting device is relatively poor when encountering conditions such as frozen soil. In this case, a double-acting hydraulic cylinder is needed to increase the downward pressure (commonly known as high pressure). However, if a double-acting hydraulic cylinder is used, it will cause energy loss when encountering non-frozen soil conditions.

[0003] For example, application number CN202222461845.3 discloses a hydraulic lifting and hydraulic output system for a tractor. The electrically controlled lifting valve assembly includes an electrically controlled lifting valve housing, a proportional lifting valve installed inside the housing on the right side for parameter adjustment, a constant pressure differential valve located at the lower end of the pipeline inside the housing for pressure stabilization, a lifting safety valve connected to the upper left end of the constant pressure differential valve for pressure relief protection, and a proportional lowering valve installed opposite to the left side of the proportional lifting valve for auxiliary parameter adjustment. The upper and lower end pipelines of the proportional lifting valve are respectively connected to the gear pump and the upper end of the constant pressure differential valve. The pipelines are connected, and the proportional riser valve and the proportional fallr valve on the left side operate in opposite directions to ensure that the proportional riser valve and the proportional fallr valve cooperate to adjust or continuously control the pressure and flow parameters of the hydraulic system. The constant pressure differential valve has pipeline interfaces at both ends, and the constant pressure differential valve is connected to the gear pump pipeline through the pipeline at the bottom to ensure that the internal pressure of the hydraulic system is stabilized through the constant pressure differential valve. The lifting safety valve is connected to the outer pipeline through pipeline interfaces at both ends, and the bottom output end of the lifting safety valve is connected to the pipeline at the left output end of the constant pressure differential valve to ensure that the lifting safety valve can stabilize the pipeline pressure relief protection activity.

[0004] The hydraulic cylinders in the aforementioned application are single-acting cylinders. When encountering frozen soil conditions, the pressure is insufficient, making it impossible to achieve both single and double-acting capabilities, resulting in poor applicability. Utility Model Content

[0005] To address the technical problem that existing hydraulic systems cannot perform both single and dual functions and have poor applicability, this utility model provides a hydraulic system and hydraulic device that solves the aforementioned technical problems.

[0006] To solve the above-mentioned technical problems, this utility model provides a hydraulic system for switching between single and double action of a lifting cylinder, comprising:

[0007] The large cavity oil circuit includes a large cavity inlet oil circuit and a large cavity return oil circuit, both of which are connected to the large cavity of the lifting cylinder. A lifting valve for controlling the on / off state is installed on the large cavity inlet oil circuit, and a lowering valve for controlling the on / off state is installed on the large cavity return oil circuit.

[0008] The small-cavity oil passage is connected to the small cavity of the lifting cylinder;

[0009] A switching valve controls the oil inlet of the large chamber oil inlet circuit and the oil inlet and outlet of the small chamber oil circuit;

[0010] An unloading oil circuit is connected in parallel to the large cavity oil inlet oil circuit. An unloading valve is installed on the unloading oil circuit. The unloading valve opens and closes under the action of the oil inlet pressure and oil outlet pressure of the lifting valve.

[0011] According to one embodiment of the present invention, the pressure oil is delivered to the switching valve in two separate paths: one path of pressure oil reaches the switching valve via the inlet oil path, and the other path of pressure oil reaches the switching valve via the intermediate oil path.

[0012] According to one embodiment of the present invention, when the switching valve is in the neutral position, the pressure oil arriving through the intermediate oil passage can be unloaded through the unloading oil passage; when the switching valve is in the first working position, the pressure oil arriving through the intermediate oil passage arrives at the large chamber oil inlet oil passage, and the small chamber oil passage returns oil through the switching valve; when the switching valve is in the second working position, the pressure oil arriving through the oil inlet oil passage arrives at the small chamber oil passage.

[0013] According to one embodiment of the present invention, the lifting valve has an oil inlet P3, an oil outlet P4, and an oil return port T2. The oil inlet P3 is connected to a switching valve, the oil outlet P4 is connected to the large cavity of the lifting cylinder, and the oil return port T2 is connected to the oil tank. A one-way valve is provided between the oil outlet P4 and the large cavity of the lifting cylinder. In the initial state, the oil outlet P4 is connected to the oil return port T2; after the lifting valve is reversed, the oil inlet P3 and the oil outlet P4 are connected.

[0014] According to one embodiment of the present invention, it further includes a control main valve, wherein there are several control main valves configured for the actuator, the control main valves are arranged upstream of the switching valve, the intermediate oil passage passes through the control main valves, and the pressure oil reaches the control main valves through the inlet oil passage.

[0015] This utility model also provides a hydraulic device for use in a hydraulic system, comprising:

[0016] The switching assembly includes a first valve body, and a switching valve is assembled inside the first valve body.

[0017] Tail coupling, including a second valve body, wherein a lifting valve, a lowering valve and an unloading valve are assembled in the second valve body;

[0018] The first valve body and the second valve body are stacked and fixed together.

[0019] According to one embodiment of the present invention, the lifting valve and the unloading valve are coaxially arranged. One end of the lifting valve is provided with an adjustment structure, which includes an adjusting screw and a push rod. The adjusting screw is threaded onto the second valve body. The push rod abuts against the end face of the adjusting screw under the action of the lifting spring. The push rod passes through the unloading valve core of the unloading valve and slides with it. The end of the push rod away from the adjusting screw forms a stepped limiting surface, and the lifting spring abuts against the stepped limiting surface.

[0020] According to one embodiment of the present invention, the descending valve includes a descending valve sleeve, a descending piston, a descending valve core, and a descending spring. The descending valve sleeve is fitted into the second valve body. The descending piston is slidably fitted into the descending valve sleeve. One end of the descending piston can abut against the inner wall of the descending valve sleeve to form a blockage. The other end of the descending piston is provided with a screw plug. The descending valve core is slidably fitted into the descending piston. In the initial state, the descending valve core abuts against the descending piston under the action of the descending spring, and drives the descending piston to abut against the descending valve sleeve, blocking the communication between the oil ports. After the descending valve core reverses direction, it pushes the screw plug, causing the descending piston to slide and release the abutment, and the oil ports are connected.

[0021] According to one embodiment of the present invention, the lowering valve further includes a pressure regulating structure, which includes a transmission-fitting worm gear and a worm. The worm rotates to drive the worm gear to move axially, the worm gear acts on the lowering spring, and the worm is tilted.

[0022] According to one embodiment of the present invention, both the lifting valve and the lowering valve are solenoid valves, and the solenoid components of the lifting valve and the lowering valve are respectively located on opposite sides of the second valve block.

[0023] Based on the above technical solution, the technical effects that this utility model can achieve are as follows:

[0024] 1. The hydraulic system of this utility model, by setting up a large-cavity oil circuit including a large-cavity inlet oil circuit and a large-cavity return oil circuit, and simultaneously setting up a switching valve to control the oil inlet of the large-cavity inlet oil circuit and the oil inlet and outlet of the small-cavity oil circuit, can switch the single-acting or double-acting of the lifting cylinder by coordinating the switching valve, lifting valve and lowering valve to control the direction of the oil. For example, the large-cavity return oil circuit can be kept in a connected state by the lowering valve, and the small-cavity oil circuit can be kept connected to the oil tank by the switching valve. At this time, the lifting cylinder returns oil in the large cavity and replenishes oil in the small cavity under vacuum, thus realizing the single-acting lowering of the lifting cylinder, with low downward pressure, more energy-saving, and suitable for non-frozen soil conditions; it can also be switched... The valve controls the pressure oil to enter the small chamber oil circuit, and the lowering valve controls the large chamber return oil circuit to be in a connected state. At this time, the small chamber of the lifting cylinder receives oil, and the large chamber receives oil, which can realize the double-acting descent of the lifting cylinder with high downward pressure, suitable for frozen soil conditions. As for the setting of the unloading oil circuit, when the lifting valve is in the open state, the pressure oil entering the large chamber oil circuit can be unloaded through the unloading oil circuit. In addition, the unloading valve opens and closes under the action of the inlet and outlet pressures of the lifting valve, so that the pressure difference between the inlet and outlet pressures of the lifting valve approaches a fixed value, that is, the unloading spring force, which makes the lifting action have load-sensitive characteristics.

[0025] 2. In the hydraulic system of this utility model, the pressurized oil can reach the switching valve through the inlet oil circuit and the intermediate oil circuit. When the switching valve is in the neutral position, the pressurized oil can enter the large cavity inlet oil circuit through the switching valve, and then be unloaded through the unloading oil circuit. The pressure will not impact the valve structure, which can play a protective role.

[0026] 3. The hydraulic system of this utility model specifically sets the oil port structure of the lifting valve so that when the lifting valve is in the initial state, the oil outlet of the lifting valve is connected to the oil return port and is in a low-pressure state. At this time, when the pressure oil enters the oil inlet circuit of the large chamber, it can be unloaded through the unloading valve. When the lifting valve is reversed, the oil inlet and oil outlet are connected, and the unloading valve can control the pressure difference between the oil inlet and oil outlet of the lifting valve.

[0027] 4. The hydraulic system of this utility model also includes a control main valve, and the pressure oil can also control the operation of other actuators. The intermediate oil circuit passes through the control main valve to ensure the mid-position unloading function.

[0028] 5. The hydraulic device of this utility model is equipped with a switching link and a tail link, which can assemble the valve into the corresponding valve body and then stack and fix the valve body to form an integral structure, which is convenient for assembly; the lifting valve and the unloading valve are set coaxially, which can reduce the number of mounting holes; the adjustment structure can adjust the pressure of the lifting valve on the one hand, and guide the unloading valve core of the unloading valve on the other hand; the plate structure can easily increase or decrease the number of expansion working links as needed.

[0029] 6. The hydraulic device of this utility model has a structure of lowering valve that, in the initial state, the lowering valve core, under the action of the lowering spring, drives the lowering piston to abut against the lowering valve sleeve to form a blockage. After the lowering valve core reverses direction, it can push the lowering piston away from the lowering valve sleeve to achieve connection. The pressure regulating structure of the lowering valve adopts a worm gear, with the worm gear obliquely cut upwards, which saves space and facilitates the pressure regulation of the lowering valve. Attached Figure Description

[0030] Figure 1 This is a hydraulic schematic diagram of the hydraulic system according to Embodiment 1 of this utility model;

[0031] Figure 2 for Figure 1 Enlarged view of part A;

[0032] Figure 3 This is a schematic diagram of the switching link structure;

[0033] Figure 4 This is a state diagram showing the switching valve in its first operating position.

[0034] Figure 5 This is a state diagram showing the switching valve in its second operating position.

[0035] Figure 6 This is a cross-sectional view of the switching coupling at the mounting hole of the switching valve;

[0036] Figure 7 This is a schematic diagram of the tail section structure;

[0037] Figure 8 A schematic diagram showing the structure in which the lift valve and unloading valve are installed in the second valve body;

[0038] Figure 9 A schematic diagram of the structure in which the downcomer valve is installed in the second valve body;

[0039] Figure 10 This is a cross-sectional view of the tail connector at the lift valve and unloading valve;

[0040] Figure 11 This is a cross-sectional view of the tail connector at the pressure regulating structure of the downcomer valve;

[0041] Figure 12 This is a hydraulic schematic diagram of the hydraulic system according to Embodiment 2 of this utility model;

[0042] In the diagram: 1-Large chamber oil passage; 11-Large chamber inlet oil passage; 111-One-way valve; 12-Large chamber return oil passage; 2-Small chamber oil passage; 3-Lifting valve; 31-Lifting valve core; 32-Lifting spring; 33-First electromagnetic assembly; 34-Adjusting structure; 341-Adjusting screw; 342-Push rod; 343-Locking nut; 4-Lowering valve; 41-Lowering valve sleeve; 42-Lowering piston; 421-Plug; 43-Lowering valve core; 431-Spring seat; 44-Lowering spring; 45-Pressure regulating structure; 451-Worm gear; 452-Worm; 46-Second electromagnetic assembly; 5-Cut 51-Valve replacement; 6-Unloading oil circuit; 61-Unloading valve; 611-Unloading valve core; 612-Unloading spring; 71-First safety valve; 72-Second safety valve; 81-Inlet oil circuit; 82-Intermediate oil circuit; 9-Control main valve; 10-Switching connection; 101-First valve body; 102-First oil port; 103-Second oil port; 104-First fixing hole; 20-Tail connection; 201-Second valve body; 202-Second fixing hole; 203-Plug; 30-First connection; 40-Working connection; 100-Lifting cylinder; 1001-Large chamber; 1002-Small chamber. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0046] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0047] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0048] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0049] Example 1

[0050] like Figure 1-11 As shown, this embodiment provides a hydraulic system for switching between single and double action of a lifting cylinder 100. The hydraulic system includes a large-cavity oil circuit 1, a small-cavity oil circuit 2, and a switching valve 5. The large-cavity oil circuit 1 is configured for the large cavity 1001 of the lifting cylinder 100. The large-cavity oil circuit 1 includes a large-cavity inlet oil circuit 11 and a large-cavity return oil circuit 12. Both the large-cavity inlet oil circuit 11 and the large-cavity return oil circuit 12 are connected to the large cavity 1001 of the lifting cylinder 100. The large-cavity inlet oil circuit 11 is used for the inlet of oil into the large cavity 1001 of the lifting cylinder 100, and the large-cavity return oil circuit 12 is used for the return of oil from the large cavity 1001 of the lifting cylinder 100. Small cavity oil passage 2 is set for small cavity 1002 of lifting cylinder 100. Small cavity oil passage 2 is connected to small cavity 1002 of lifting cylinder 100 and is used for oil inlet and outlet of small cavity 1002. Switching valve 5 controls the oil inlet of large cavity oil passage 11 and the oil inlet and outlet of small cavity oil passage 2.

[0051] like Figure 1 As shown, a lift valve 3 is installed on the large cavity oil inlet passage 11, which controls the opening and closing of the large cavity oil inlet passage 11. The lift valve 3 has an oil inlet port P3, an oil outlet port P4, and a return port T2. The oil inlet port P3 is connected to the switching valve 5, the oil outlet port P4 is connected to the large cavity 1001 of the lifting cylinder 100, and the return port T2 is connected to the oil tank. In the initial state, the oil outlet port P4 of the lift valve 3 is connected to the return port T2, and the large cavity oil inlet passage 11 is in the open state; after reversing, the oil inlet port P3 and the oil outlet port P4 of the lift valve 3 are connected, and the large cavity oil inlet passage 11 is in the open state.

[0052] As a preferred technical solution in this embodiment, the switching of the lift valve 3 can be achieved through electromagnetic drive, electro-hydraulic drive, motor drive, manual drive, etc. In this embodiment, the switching of the lift valve 3 is set to electromagnetic drive. Specifically, as shown in the example... Figure 8 , 10 As shown, a lifting spring 32 is provided at one end of the lifting valve core 31 of the lifting valve 3, and a first electromagnetic component 33 is provided at the other end. In the initial state, the first electromagnetic component 33 is de-energized, and under the action of the lifting spring 32, the lifting valve core 31 blocks the connection between the oil inlet P3 and the oil outlet P4. When the first electromagnetic component 33 is energized under the control of electromagnetic signal a2, the first electromagnetic component 33 drives the lifting valve core 31 to reverse the force of the lifting spring 32, and the oil inlet P3 and the oil outlet P4 are connected by the reversed lifting valve core 31.

[0053] As a preferred technical solution in this embodiment, such as Figure 1 As shown, in order to ensure the direction of the oil flow in the large cavity oil inlet passage 11, a one-way valve 111 is also provided on the large cavity oil inlet passage 11. In this embodiment, the one-way valve 111 is located between the lifting valve 3 and the large cavity 1001 of the lifting cylinder 100.

[0054] like Figure 1 As shown, a downcomer valve 4 is installed on the large cavity return oil passage 12, which is used to control the opening and closing of the large cavity return oil passage 12. The downcomer valve 4 has an oil inlet P5 and an oil return port T3. The oil inlet P5 is connected to the large cavity 1001 of the lifting cylinder 100, and the oil return port T3 is connected to the oil tank. In the initial state, the oil return port T3 of the downcomer valve 4 is connected to the oil inlet P5 in one direction, and the large cavity 1001 cannot return oil through the large cavity return oil passage 12; after reversing, the oil inlet P5 of the downcomer valve 4 is connected to the oil return port T3, and the large cavity 1001 can return oil through the large cavity return oil passage 12.

[0055] As a preferred technical solution in this embodiment, the switching of the descending valve 4 can be achieved through electromagnetic drive, electro-hydraulic drive, motor drive, manual drive, etc. In this embodiment, the switching of the descending valve 4 is set to electromagnetic drive. Specifically, as shown in the example... Figure 9 As shown, the end of the lowering valve 4 is provided with a lowering spring 44 and a second electromagnetic component 46. In the initial state, the second electromagnetic component 46 is de-energized. Under the action of the lowering spring 44, the lowering valve 4 controls the return port T3 to connect unidirectionally to the inlet port P5. The oil can only flow through the return port T3 to the inlet port P5, which can be used to replenish oil when the large chamber 1001 is sucked in air. When the second electromagnetic component 46 is energized under the control of electromagnetic signal b2, the second electromagnetic component 46 drives the lowering valve core 43 to reverse the force of the lowering spring 44, and the inlet port P5 is connected to the return port T3.

[0056] As a preferred technical solution in this embodiment, such as Figure 9As shown, the specific structure of the lowering valve 4 can be configured to include a lowering valve sleeve 41, a lowering piston 42, a lowering valve core 43, and a lowering spring 44. The lowering piston 42 is slidably assembled inside the lowering valve sleeve 41, and the lowering valve core 43 is slidably assembled inside the lowering piston 42. One end of the lowering piston 42 can abut against the inner wall of the lowering valve sleeve 41 to block the communication between the oil inlet P5 and the oil return port T3; a screw plug 421 is formed at the other end of the lowering piston 42; one end of the lowering valve core 43 is slidably assembled inside the lowering piston 42, and the lowering valve core 44... The other end of the valve core 43 extends out from the lowering piston 42 and is equipped with a lowering spring 44. Under the action of the lowering spring 44, the portion of the lowering valve core 43 located inside the lowering piston 42 can abut against the inner wall of the lowering piston 42. The lowering valve core 43 pushes the lowering piston 42 to press against the inner wall of the lowering valve sleeve 41 to form a blockage. When the lowering valve core 43 reverses its direction against the force of the lowering spring 44, the lowering valve core 43 can push the lowering piston 42 to slide by pushing the screw plug 421, releasing the abutment, and connecting the oil inlet P5 and the oil return T3. Preferably, a second electromagnetic component 46 is used to drive the lowering valve core 43 to reverse its direction. Both the lowering spring 44 and the second electromagnetic component 46 are located near the end of the lowering valve core 43 that extends out from the lowering piston 42. Preferably, a spring seat 431 is equipped at the end of the lowering valve core 43 that extends out from the lowering piston 42. The lowering spring 44 provides a force to the lowering valve core 43 toward the second electromagnetic component 46 by acting on the spring seat 431.

[0057] As a preferred technical solution in this embodiment, such as Figure 9 , 11 As shown, the lowering valve 4 also includes a pressure regulating structure 45, which includes a worm gear 451 and a worm 452. The worm gear 451 is threaded onto the second valve body 201 and is fitted with a gap on one end of the lowering valve core 43 that extends out of the lowering piston 42. The worm 452 meshes with the worm gear 451. The lowering spring 44 is located between the worm gear 451 and the spring seat 431. When the worm 452 is rotated, the axial position of the worm gear 451 can be adjusted, thereby adjusting the pre-compression of the lowering spring 44.

[0058] like Figure 1 As shown, the switching valve 5 is used to control the oil inlet of the large chamber oil inlet circuit 11 and the oil inlet and outlet of the small chamber oil circuit 2. The switching valve 5 is a three-position valve. When the switching valve 5 is in the neutral position, the pressurized oil can enter the large chamber oil inlet circuit 11 through the switching valve 5; when the switching valve 5 is in the first working position, the pressurized oil reaches the large chamber oil inlet circuit 11, and the small chamber oil circuit 2 is connected to the oil tank through the switching valve 5; when the switching valve 5 is in the second working position, the pressurized oil reaches the small chamber oil circuit 2.

[0059] Specifically, such as Figure 2-5As shown, the switching valve 5 has a first oil inlet P1, a second oil inlet P2, a return oil inlet T1, a working oil inlet A1, a working oil inlet B1, and an oil outlet C1. Both the first oil inlet P1 and the second oil inlet P2 can be used to introduce pressurized oil. The return oil inlet T1 connects to the oil tank. The working oil inlet A1 can be blocked (or can be omitted). The working oil inlet B1 connects to the small chamber oil passage 2, and the oil outlet C1 connects to the large chamber oil inlet oil passage 11. In the initial state, as... Figure 2-3 As shown, the second oil inlet P2 is connected to the oil outlet C1; when the switching valve 5 is in the first working position, as... Figure 2 , 4 As shown, the second oil inlet P2 is connected to the oil outlet C1, and the working oil port B1 is connected to the return oil port T1; when the switching valve 5 is in the second working position, as... Figure 2 , 5 As shown, the first oil inlet P1 is connected to the working oil inlet B1.

[0060] like Figure 1 As shown, the oil outlet C1 of the switching valve 5 is also connected to the unloading oil passage 6. The unloading oil passage 6 is equipped with an unloading valve 61, which is connected in parallel with the lifting valve 3. When the pressure oil enters the large cavity oil inlet passage 11 through the switching valve 5 and the lifting valve 3 is in the initial state, the pressure oil can be unloaded through the unloading oil passage 6.

[0061] As a preferred technical solution in this embodiment, the switching valve 5 can be switched by electromagnetic drive, electro-hydraulic drive, motor drive, manual drive, etc. In this embodiment, the switching valve 5 is set to be switched by electromagnetic drive. Specifically, both ends of the switching valve core 51 of the switching valve 5 are provided with electromagnetic components. Under the control of electromagnetic signal a1, the switching valve 5 can be switched to the first working position, and under the control of electromagnetic signal b1, the switching valve 5 can be switched to the second working position.

[0062] As a preferred technical solution in this embodiment, such as Figure 8 , 10 As shown, the unloading valve 61 has an oil inlet P6 and an oil outlet P7. The oil inlet P6 is connected to the oil outlet C1 of the switching valve 5, and the oil outlet P7 is connected to the oil tank. The unloading valve 61 opens and closes under the action of the oil inlet pressure and the oil outlet pressure of the lifting valve 3. Specifically, the unloading valve 61 includes an unloading valve core 611. One end of the unloading valve core 611 is provided with an unloading spring 612. The end of the unloading valve core 611 with the unloading spring 612 is connected to the oil outlet pressure of the lifting valve 3, that is, it is connected to the oil outlet P4 of the lifting valve 3 through an oil passage. The other end of the unloading valve core 611 is connected to the oil inlet pressure of the lifting valve 3, that is, it is connected to the oil inlet P3 of the lifting valve 3 through an oil passage.

[0063] like Figure 1As shown, the pressurized oil can reach the switching valve 5 in two paths. One path of pressurized oil reaches the switching valve 5 via the inlet oil passage 81, and the other path of pressurized oil reaches the switching valve 5 via the intermediate oil passage 82. Specifically, the inlet oil passage 81 is connected to the first pressure port P1 of the switching valve 5, and the intermediate oil passage 82 is connected to the second pressure port P2 of the switching valve 5. Preferably, an inlet check valve is provided on the inlet oil passage 81 to control the unidirectional flow of pressurized oil to the switching valve 5.

[0064] As a preferred technical solution in this embodiment, a safety valve is also provided to ensure that the system pressure is not too high. Specifically, the large chamber 1001 of the lifting cylinder 10 is connected to a first safety valve 71. When the oil pressure in the large chamber 1001 of the lifting cylinder 10 is too high, the oil can be depressurized to the oil tank through the first safety valve 71. A second safety valve 72 is provided on the main oil inlet line of the pressurized oil. When the oil pressure is too high, it can be depressurized to the oil tank through the second safety valve 72.

[0065] This embodiment also provides a hydraulic device, which is a plate-type structure, including a switching link 10 and a tail link 20, such as... Figure 3-6 As shown, the switching linkage 10 includes a first valve body 101, and the switching valve 5 is assembled inside the first valve body 101, as follows: Figure 7-11 As shown, the tail connector 20 includes a second valve body 201, a lifting valve 3, a lowering valve 4 and an unloading valve 61 are assembled inside the second valve body 201, and the first valve body 101 and the second valve body 102 are stacked and fixed.

[0066] like Figure 3-6 As shown, the switching valve 5 is assembled into the first valve body 101, and the switching valve core 51 is slidably assembled into the first valve body 101. Electromagnetic components on both sides are respectively assembled onto the two side surfaces of the first valve body 101 (not shown in the figure). Multiple oil passages are provided inside the first valve body 101. A first oil inlet P1, a second oil inlet P2, a return oil port T1, a working oil port A1, a working oil port B1, an oil outlet C11, and an oil outlet C12 are formed on the outer periphery of the switching valve core 51. Working oil ports A1 and B1 extend through oil passages to the outer surface of the first valve body 101, forming a first oil port 102 and a second oil port 103, respectively. The first oil port 102 is blocked. Figure 6 As shown, oil outlet C11 and oil outlet C12 are connected at oil outlet C1.

[0067] As a preferred embodiment, the first valve body 101 is provided with a first fixing hole 104 for easy fixing to other valve bodies. There are at least two first fixing holes 104; in this embodiment, four first fixing holes 104 are provided.

[0068] like Figure 7 , 8As shown in Figure 10, the lifting valve 3 and the unloading valve 61 are coaxially assembled within the second valve body 201. The lifting valve 3 may also include an adjusting structure 34, which includes an adjusting screw 341 and a push rod 342. The adjusting screw 341 is threaded onto the second valve body 201, with one end extending into the second valve body 201 and acting on the lifting spring 32 via the push rod 342. The push rod 342 passes through the unloading valve core 611 and slides with it.

[0069] As a preferred embodiment, the second valve body 201 has a through mounting hole, in which both the lifting valve 3 and the unloading valve 61 are mounted. The lifting valve core 3 is slidably mounted in the mounting hole and close to the first end opening of the mounting hole. The first electromagnetic component 33 is mounted on the outer side wall of one end of the second valve body 201, located outside the first end opening, and acts on the lifting valve core 3. A screw plug 203 is provided at the second end opening of the mounting hole, and the adjusting screw 341 is threaded onto the screw plug 203. One end of the push rod 342 acts on the lifting spring 32, and the other end abuts against the adjusting screw 341. Preferably, the end of the push rod 342 that acts on the lifting spring 32 forms a stepped limiting surface, and the lifting spring 32 abuts against the stepped limiting surface. More preferably, a groove is formed on the end face of the lifting valve core 3 away from the first electromagnetic component 33, the lifting spring 32 is located in the groove, the push rod 342 extends into the groove and acts on the lifting spring 32, and there is a gap between the push rod 342 and the inner wall of the groove.

[0070] As a preferred technical solution in this embodiment, the adjusting screw 341 is assembled on the screw plug 302, and the push rod 342 slides through the unloading valve core 611. The unloading valve core 611 is slidably assembled in the mounting hole. The above assembly can realize the coaxial assembly of the adjusting screw 341 and the push rod 342, and there will be no axial misalignment between the adjusting screw 341 and the push rod 342.

[0071] As a preferred technical solution in this embodiment, the outer periphery of the lifting valve core 31 is provided with an oil inlet P3, an oil outlet P4, and an oil return port T2, and the outer periphery of the unloading valve core 611 is provided with an oil inlet P6 and an oil outlet P7. The cavity V1 between the unloading valve core 611 and the lifting valve core 31 is connected to the oil inlet P3 through a small hole on the lifting valve core 31; the cavity V2 between the unloading valve core 611 and the screw plug 203 is connected to the oil outlet P4 through an oil passage in the second valve body 201. Therefore, the pressure difference before and after the lifting valve core 31 is: pressure difference = pressure at the oil inlet P3 - pressure at the oil outlet P4 = pressure in cavity V1 - pressure in cavity V2 = force of the unloading spring. Ignoring the change in force of the unloading spring 612 caused by the displacement of the unloading valve core 611, the force of the unloading spring 612 is approximately a fixed value. Therefore, the pressure difference before and after the lifting valve core 31 is approximately a fixed value, which makes the lifting action have load-sensitive characteristics.

[0072] The lowering valve 4 is assembled inside the second valve body 201, such as Figure 11 As shown, the worm 452 of the pressure regulating structure 45 of the downcomer valve 4 can be inclined. Specifically, the worm 452 is inclined upward, which can save space and facilitate the pressure regulation of the downcomer valve 4.

[0073] The one-way valve 111 and the first safety valve 71 are both assembled inside the second valve body 201. The second valve body 201 is provided with a second fixing hole 202, which is corresponding to the first fixing hole 104. Fasteners pass through the first fixing hole 104 and the second fixing hole 202 to fix the first valve body 101 and the second valve body 201 in a stacked manner.

[0074] As a preferred technical solution of this embodiment, the first electromagnetic component 33 and the second electromagnetic component 46 are respectively disposed on two opposite sides of the second valve body 201.

[0075] The hydraulic device also includes a first section 30, which includes a third valve body. An oil inlet passage 81 and an intermediate oil passage 82 are located within the third valve body. The third valve body is equipped with a main pressure port P, which introduces pressurized oil. The pressurized oil is divided into two paths via the oil inlet passage 81 and the intermediate oil passage 82. A second safety valve 72 is also located within the third valve body.

[0076] Based on the above technical solution, the hydraulic system and hydraulic device of this embodiment, when used to control the operation of the lifting cylinder 100, have the following single-acting and double-acting control logic table:

[0077] Table 1 Single / Double Action Control Logic Table

[0078] Different modes Electromagnetic signal a1 Electromagnetic signal b1 Electromagnetic signal a2 Electromagnetic signal b2 Single-acting enhancement + - + - Single-acting decrease + - - + Dual-effect enhancement + - + - Dual-effect decrease - + - + standby - - - -

[0079] Two examples of descent conditions are given.

[0080] 1. Single-acting decrease

[0081] Switching valve 5 is switched to the first working position under the control of electromagnetic signal a1, and lowering valve 4 is switched under the control of electromagnetic signal b2. Pressurized oil enters switching valve 5 through the second inlet P2, then flows out through the outlet C1 of switching valve 5 to the inlet P3 of lifting valve 3, and then reaches the oil tank through unloading oil passage 6. The large chamber 1001 of lifting cylinder 100 returns oil through the large chamber return oil passage 12. The small chamber 1002 of lifting cylinder 100 is connected to the oil tank. If the small chamber 1002 of cylinder 100 is emptied, oil can be replenished through switching valve 5. At this time, there is no high-pressure oil in the small chamber 1002 of cylinder 100 (commonly known as non-forced pressure).

[0082] 2. Dual-effect decrease

[0083] Under the control of electromagnetic signal b1, switching valve 5 switches to the second working position, and lowering valve 4 switches under the control of electromagnetic signal b2. Pressurized oil enters switching valve 5 through the first inlet P1, then flows out through the working port B1 of switching valve 5 to the small chamber oil passage 2, and enters the small chamber 1002 of lifting cylinder 100. The large chamber 1001 of lifting cylinder 100 returns oil through the large chamber return oil passage 12. Under this condition, the small chamber 1002 of cylinder 100 (commonly known as high pressure)...

[0084] Example 2

[0085] like Figure 12 As shown, this embodiment is basically the same as embodiment one, except that: this embodiment adds a working link 40, which can be set between the first link 30 and the switching link 10. The working link 40 includes a control main valve 9, which is used to control the actuator. The intermediate oil passage 82 passes through the control main valve 9, and the pressurized oil can reach the control main valve 9 through the oil inlet passage 81.

[0086] As a preferred technical solution in this embodiment, the number of working links 40 can be set as needed. Multiple working links 40 can be stacked between the first link 30 and the switching link 10. The working link 40 is located upstream of the switching valve 5. When all control main valves 9 are in the neutral position, the pressure oil can reach the switching valve 5 through the intermediate oil passage 82.

[0087] As a preferred technical solution in this embodiment, the oil inlet circuit 81 supplies oil to each control main valve 9 in one direction.

[0088] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A hydraulic system for switching between single and double action of a lifting cylinder (100), characterized in that, include: The large cavity oil passage (1) includes a large cavity inlet oil passage (11) and a large cavity return oil passage (12), both of which are connected to the large cavity (1001) of the lifting cylinder (100). The large cavity inlet oil passage (11) is equipped with a lifting valve (3) for controlling the on-off state, and the large cavity return oil passage (12) is equipped with a lowering valve (4) for controlling the on-off state. The small cavity oil passage (2) is connected to the small cavity (1002) of the lifting cylinder (100); Switching valve (5) controls the oil inlet of the large cavity oil inlet circuit (11) and the oil inlet and outlet of the small cavity oil circuit (2); The unloading oil passage (6) is connected in parallel to the large cavity oil inlet oil passage (11). The unloading oil passage (6) is equipped with an unloading valve (61). The unloading valve (61) is opened and closed under the action of the oil inlet pressure and oil outlet pressure of the lifting valve (3).

2. A hydraulic system according to claim 1, characterized in that, The pressure oil is divided into two paths to reach the switching valve (5). One path of pressure oil reaches the switching valve (5) through the inlet oil path (81), and the other path of pressure oil can reach the switching valve (5) through the intermediate oil path (82).

3. A hydraulic system according to claim 2, characterized in that, When the switching valve (5) is in the neutral position, the pressure oil arriving through the intermediate oil passage (82) can be unloaded through the unloading oil passage (6); when the switching valve (5) is in the first working position, the pressure oil arriving through the intermediate oil passage (82) arrives at the large cavity inlet oil passage (11), and the small cavity oil passage (2) returns oil through the switching valve (5); when the switching valve (5) is in the second working position, the pressure oil arriving through the inlet oil passage (81) arrives at the small cavity oil passage (2).

4. A hydraulic system according to claim 1, characterized in that, The lifting valve (3) has an oil inlet P3, an oil outlet P4 and an oil return port T2. The oil inlet P3 is connected to the switching valve (5), the oil outlet P4 is connected to the large cavity (1001) of the lifting cylinder (100), and the oil return port T2 is connected to the oil tank. A one-way valve (111) is provided between the oil outlet P4 and the large cavity (1001) of the lifting cylinder (100). In the initial state, the oil outlet P4 is connected to the oil return port T2. After the lifting valve (3) is reversed, the oil inlet P3 and the oil outlet P4 are connected.

5. A hydraulic system according to claim 2, characterized in that, It also includes a control main valve (9), which consists of several valves and is set for the actuator. The control main valve (9) is located upstream of the switching valve (5). The intermediate oil passage (82) passes through the control main valve (9), and the pressurized oil reaches the control main valve (9) through the oil inlet passage (81).

6. A hydraulic device, characterized in that, For use in the hydraulic system according to any one of claims 1-5, comprising: The switching link (10) includes a first valve body (101), and the switching valve (5) is assembled inside the first valve body (101); Tail connector (20) includes a second valve body (201), a lifting valve (3), a lowering valve (4) and an unloading valve (61) assembled inside the second valve body (201); The first valve body (101) and the second valve body (201) are stacked and fixed.

7. A hydraulic device according to claim 6, characterized in that, The lifting valve (3) and the unloading valve (61) are coaxially arranged. One end of the lifting valve (3) is provided with an adjustment structure (34). The adjustment structure (34) includes an adjustment screw (341) and a push rod (342). The adjustment screw (341) is threaded onto the second valve body (201). The push rod (342) abuts against the end face of the adjustment screw (341) under the action of the lifting spring (32). The push rod (342) passes through the unloading valve core (611) of the unloading valve (61) and slides with it. The end of the push rod (342) away from the adjustment screw (341) forms a stepped limiting surface. The lifting spring (32) abuts against the stepped limiting surface.

8. A hydraulic device according to claim 6, characterized in that, The lowering valve (4) includes a lowering valve sleeve (41), a lowering piston (42), a lowering valve core (43), and a lowering spring (44). The lowering valve sleeve (41) is assembled inside the second valve body (201). The lowering piston (42) is slidably assembled inside the lowering valve sleeve (41). One end of the lowering piston (42) can abut against the inner wall of the lowering valve sleeve (41) to form a blockage. The other end of the lowering piston (42) is provided with a screw plug (421). The lowering valve core (43) is slidably assembled inside the lowering piston (42). In the initial state, the lowering valve core (43) abuts against the lowering piston (42) under the action of the lowering spring (44) and drives the lowering piston (42) to abut against the lowering valve sleeve (41), blocking the connection between the oil ports. After the lowering valve core (43) reverses direction, it pushes the screw plug (421), causing the lowering piston (42) to slide and release the abutment, and the oil ports are connected.

9. A hydraulic device according to claim 8, characterized in that, The lowering valve (4) also includes a pressure regulating structure (45), which includes a transmission-coordinated worm gear (451) and a worm (452). The worm (452) rotates to drive the worm gear (451) to move axially. The worm gear (451) acts on the lowering spring (44), and the worm (452) is tilted.

10. A hydraulic device according to claim 6, characterized in that, Both the lifting valve (3) and the lowering valve (4) are solenoid valves. The solenoid components of the lifting valve (3) and the lowering valve (4) are located on opposite sides of the second valve body (201).

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