Valve structure and hydraulic device

Abstract

The utility model relates to the technical field of hydraulic pressure, in particular to a valve structure and a hydraulic device. A valve structure comprises a valve body which is internally provided with a pressure oil channel, a first working oil channel, a second working oil channel and an oil return oil channel; the valve element is assembled on the valve body in a sliding mode, and the valve element controls connection and disconnection between the oil channels in a sliding mode; when the valve element is located at the middle position, a gap AI is formed between the valve element located between the pressure oil channel and the first working oil channel and the valve body, a gap BI is formed between the valve element located between the pressure oil channel and the second working oil channel and the valve body, and the covering amount of the gap AI is larger than that of the gap BI. The utility model further provides a hydraulic device. The hydraulic device comprises a valve structure; the actuator comprises a cylinder body and a telescopic rod, the first working oil duct is communicated with a rodless cavity of the actuator, and the second working oil duct is communicated with a rod cavity of the actuator. The technical problem that a control valve in the prior art cannot accurately control an oil cylinder and prevent the oil cylinder from stretching out and drawing back automatically is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulics, and particularly relates to a valve structure and a hydraulic device. Background Art

[0002] During the long-term operation of an excavator, the P port is continuously under high pressure, while the swing spool is always in the middle position. The high-pressure oil at the P port leaks to the bridge circuit, and the high-pressure oil in the bridge circuit leaks to the working port through the gap. The oil at the working port then leaks to the T port through the gap. Due to the leakage, the pressure at the working port changes, causing the oil cylinder to extend automatically. When the excavator bucket starts or stops under heavy load during slewing, the inertial force acts on the large or small chamber of the swing oil cylinder, which can cause the oil cylinder to extend or retract.

[0003] To solve the above-mentioned problems, the prior art has proposed solutions. For example, the document with the application number CN202321576333.X discloses a new type of spool valve. The spool is arranged in the valve body assembly. The valve body assembly is provided with an oil inlet, an oil return port, a first working oil port, a second working oil port and multiple chambers. The oil inlet is connected to the first working oil port through a first flow channel, and the oil inlet is connected to the second working oil port through a second flow channel. The spool is movably arranged between the multiple chambers to control the connection or disconnection between the multiple chambers. Radial unloading holes and axial unloading holes are provided on the spool. The radial unloading holes are connected to the axial unloading holes, and the radial unloading holes and the axial unloading holes are adapted to connect the chambers and the oil return port to unload to the oil return port and cut off the leakage path from the oil inlet to the first working oil port and the second working oil port. That is, the pressure in the bridge circuit is connected to the T through the hollow spool, blocking the leakage of the P port pressure to the working port and causing the pressures in the two chambers of the oil cylinder to increase. Under the condition of continuous high pressure at the P port, the oil cylinder can remain stationary. However, when the inertial force of the excavator bucket during heavy-load slewing start and stop acts on the large or small chamber of the swing oil cylinder, the oil in the oil cylinder will leak to the T flow channel and the bridge flow channel simultaneously at this time, and the oil cylinder will still extend and retract automatically. In addition, the processing of the hollow spool is difficult and the cost is high. Summary of the Utility Model

[0004] In order to solve the technical problem that the control valve in the prior art cannot accurately control the oil cylinder and prevent the oil cylinder from automatically extending and retracting, the utility model provides a valve structure and a hydraulic device, which solve the above technical problems.

[0005] In order to solve the above technical problems, the utility model provides a valve structure, including:

[0006] A valve body, in which a pressure oil passage, a first working oil passage, a second working oil passage and an oil return passage are provided;

[0007] Spool valve, the spool valve is slidably assembled in the valve body, and the spool valve slidably controls the on-off between the oil passages;

[0008] When the spool valve is in the middle position, a gap AI is formed between the spool valve and the valve body between the pressure oil passage and the first working oil passage, a gap BI is formed between the spool valve and the valve body between the pressure oil passage and the second working oil passage, a gap AO is formed between the spool valve and the valve body between the first working oil passage and the oil return passage, and a gap BO is formed between the spool valve and the valve body between the second working oil passage and the oil return passage. The covering amount of the gap AI is greater than the covering amount of the gap BI, and the covering amount of the gap BO is greater than the covering amount of the gap AO.

[0009] According to an embodiment of the present invention, the covering amount of the gap AI is equal to the covering amount of the gap BO, and the covering amount of the gap AO is equal to the covering amount of the gap BI.

[0010] According to an embodiment of the present invention, the pressure oil passage includes a main oil passage and two branch oil passages that are connected. The two branch oil passages are respectively a first branch oil passage and a second branch oil passage. The two branch oil passages are respectively located on both sides of the main oil passage. The first working oil passage and the second working oil passage are located on both sides of the two branch oil passages. The first branch oil passage is arranged close to the first working oil passage. The gap AI is located between the first branch oil passage and the first working oil passage, and the gap BI is located between the second branch oil passage and the second working oil passage.

[0011] According to an embodiment of the present invention, the oil return passage extends to both sides of the first working oil passage and the second working oil passage. The gap AO is located between the first working oil passage and an adjacent part of the oil return passage, and the gap BO is located between the second working oil passage and an adjacent part of the oil return passage.

[0012] According to an embodiment of the present invention, a first sealing shoulder, a second sealing shoulder, a third sealing shoulder, and a fourth sealing shoulder are formed on the spool valve. When in the middle position, the gap AI is formed between the first sealing shoulder and the hole wall of the mounting hole of the valve body, the gap BI is formed between the second sealing shoulder and the hole wall of the mounting hole of the valve body, the gap AO is formed between the third sealing shoulder and the hole wall of the mounting hole of the valve body, and the gap BO is formed between the fourth sealing shoulder and the hole wall of the mounting hole of the valve body.

[0013] According to an embodiment of the present invention, the gaps AI, BI, AO, and BO are of the same size.

[0014] The present invention also provides a hydraulic device, including:

[0015] Valve structure;

[0016] An actuator, the actuator comprising a cylinder block and a telescopic rod, the first working oil passage communicating with the rodless cavity of the actuator, and the second working oil passage communicating with the rod chamber of the actuator.

[0017] According to an embodiment of the present invention, the covering amount of the gap AO is L, and the covering amount of the gap AI is (L + ΔL), then wherein, d is the rod diameter of the telescopic rod of the actuator, and D is the cylinder diameter of the cylinder block of the actuator.

[0018] Based on the above technical solutions, the technical effects that the present invention can achieve are:

[0019] 1. For the valve structure and hydraulic device of the present invention, by setting the covering amount relationship between the gap AI and the gap BI and the covering amount relationship between the gap AO and the gap BO, when in the neutral position, more high-pressure oil in the pressure oil passage leaks to the second working oil passage, making the oil pressure in the first working oil passage lower than that in the second working oil passage. And because the pressure difference between the first working oil passage and the oil return passage is smaller than the pressure difference between the second working oil passage and the oil return passage, the flow rate of the pressure oil passage leaking to the first working oil passage through the gap AI is the same as the flow rate of the first working oil passage leaking to the oil return passage through the gap AO, and the flow rate of the pressure oil passage leaking to the second working oil passage through the gap BI is the same as the flow rate of the second working oil passage leaking to the oil return passage through the gap BO. Thus, when the valve structure controls the operation of the oil cylinder as an actuator, the first working oil passage can communicate with the rodless cavity of the oil cylinder, and the second working oil passage can communicate with the rod chamber of the oil cylinder. When in the neutral position, the oil in the pressure oil passage will not flow into the rod chamber and the rodless cavity, and thus will not affect the state of the oil cylinder rod; at the same time, the oil pressure in the rodless cavity is lower than that in the rod chamber, and the effective area of the rodless cavity is larger than that of the rod chamber, making the acting force in the rodless cavity equal to the acting force in the rod chamber. In this way, the oil cylinder rod is in a balanced state and will not automatically extend or retract.

[0020] 2. For the valve structure and hydraulic device of the present invention, by setting the covering amount of the gap AI to be equal to the covering amount of the gap BO, and the covering amount of the gap AO to be equal to the covering amount of the gap BI, when the cylinder diameter and rod diameter of the oil cylinder are known, the accurate relationship between the covering amount of the gap AI and the covering amount of the gap AO can be known, and thus the oil cylinder can be accurately controlled to prevent the oil cylinder from automatically extending or retracting; in addition, by setting the covering amount of the gap AI to be equal to the covering amount of the gap BO, when the valve core slides to control the first working oil passage to admit oil, the second working oil passage can be synchronously communicated with the oil return passage to realize oil intake in the first working oil passage and oil return in the second working oil passage; by setting the covering amount of the gap BI to be equal to the covering amount of the gap AO, when the valve core slides to control the second working oil passage to admit oil, the first working oil passage can be synchronously communicated with the oil return passage to realize oil intake in the second working oil passage and oil return in the first working oil passage.

[0021] 3. The valve structure and hydraulic device of the present utility model have the same sizes of clearance AI, clearance BI, clearance AO, and clearance BO. That is, the aperture of the mounting hole of the valve body for mounting the valve core can be set to be constant, and the outer diameters of the first sealing shoulder, second sealing shoulder, third sealing shoulder, and fourth sealing shoulder on the valve core are the same, so that the clearance between each sealing shoulder and the hole wall of the mounting hole is the same. Only the axial covering length between the valve core and the hole wall of the mounting hole of the valve body needs to be controlled, and the valve core does not need to be machined with a shaft hole, greatly reducing the processing difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the hydraulic device of the present utility model;

[0023] Figure 2 is Figure 1 an enlarged view of part C in

[0024] Figure 3 is Figure 1 an enlarged view of part D in

[0025] Figure 4 is a schematic structural diagram of the valve core;

[0026] Figure 5 is a schematic diagram of the state for achieving the force balance of the actuator;

[0027] In the figure: 1 - valve body; 11 - pressure oil passage; 111 - main oil passage; 112 - first branch oil passage; 113 - second branch oil passage; 12 - first working oil passage; 13 - second working oil passage; 14 - oil return passage; 2 - valve core; 21 - first sealing shoulder; 22 - second sealing shoulder; 23 - third sealing shoulder; 24 - fourth sealing shoulder; 3 - actuator; 31 - cylinder block; 32 - telescopic rod; 33 - rodless cavity; 34 - rod cavity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present utility model and its application or use. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model.

[0029] It should be noted that the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not require further discussion in subsequent drawings.

[0031] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary instructions, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention; the orientation words "inside, outside" refer to inside and outside the contour of each component itself.

[0032] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figure of the device. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will then be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations are made for the spatial relative descriptions used here.

[0033] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of differentiating the corresponding components. Without further statement, the above terms have no special meaning, and thus cannot be construed as limiting the protection scope of the present utility model.

[0034] As Figures 1-5 shown, this embodiment provides a valve structure, which includes a valve body 1 and a valve core 2. A plurality of oil channels are arranged in the valve body 1, and an installation hole for assembling the valve core 2 is also arranged in the valve body 1. The valve core 2 is slidably assembled in the installation hole of the valve body 1 to control the on-off between the oil channels.

[0035] The valve body 1 is in a block shape. A pressure oil channel 11, a working oil channel, and a return oil channel 14 are arranged in the valve body 1. There are two working oil channels, namely a first working oil channel 12 and a second working oil channel 13. The pressure oil channel 11, the working oil channel, and the return oil channel 14 are all communicated with the installation hole where the valve core 2 is located. One end of the first working oil channel 12 away from the installation hole forms a working oil port A, and one end of the second working oil port 13 away from the installation hole forms a working oil port B.

[0036] As a preferred technical solution of this embodiment, the pressure oil channel 11 includes a connected main oil channel 111 and two branch oil channels. The two branch oil channels are respectively a first branch oil channel 112 and a second branch oil channel 113. The first branch oil channel 112 and the second branch oil channel 113 are respectively arranged on both sides of the main oil channel 111. The pressure oil entering the main oil channel 111 through the pressure oil port P enters the first branch oil channel 112 and the second branch oil channel 113 respectively. A load-sensitive valve can be inserted at the connection of the main oil channel 111 and the two branch oil channels.

[0037] As a preferred technical solution of this embodiment, the first working oil passage 12 and the second working oil passage 13 are respectively located on both sides of the two oil distribution passages. The first working oil passage 12 is arranged close to the first oil distribution passage 112, and the second working oil passage 13 is arranged close to the second oil distribution passage 113.

[0038] As a preferred technical solution of this embodiment, the oil return passage 14 can be set to one, and the oil return passage 14 can extend to both sides of the two working oil passages. The oil return passage 14 communicates with the fuel tank T. The oil return passage 14 can also be set to two, which are respectively arranged on both sides of the two working oil passages. In this embodiment, the oil return passage 14 is set to one.

[0039] The valve core 2 is slidably assembled in the mounting hole of the valve body 1. The valve core 2 is rod-shaped. The valve core 2 is provided with a first sealing shoulder 21, a second sealing shoulder 22, a third sealing shoulder 23 and a fourth sealing shoulder 24. The first sealing shoulder 21, the second sealing shoulder 22, the third sealing shoulder 23 and the fourth sealing shoulder 24 are in sealing sliding fit with the hole wall of the mounting hole. In the initial state, the first sealing shoulder 21 and the hole wall of the mounting hole cooperate to cut off the communication between the first oil distribution passage 112 and the first working oil passage 12, the second sealing shoulder 22 and the hole wall of the mounting hole cooperate to cut off the communication between the second oil distribution passage 113 and the second working oil passage 13, the third sealing shoulder 23 and the hole wall of the mounting hole cooperate to cut off the communication between the first working oil passage 12 and the oil return passage 14, and the fourth sealing shoulder 24 and the hole wall of the mounting hole cooperate to cut off the communication between the second working oil passage 13 and the oil return passage 14.

[0040] Due to the sliding fit between the valve core 2 and the valve body 1, there are still gaps between the first sealing shoulder 21, the second sealing shoulder 22, the third sealing shoulder 23 and the fourth sealing shoulder 24 and the hole wall of the mounting hole. A gap AI is formed between the first sealing shoulder 21 and the hole wall of the mounting hole. The gap AI is located axially between the first oil distribution passage 112 and the first working oil passage 12; a gap BI is formed between the second sealing shoulder 22 and the hole wall of the mounting hole. The gap BI is located axially between the second oil distribution passage 113 and the second working oil passage 13; a gap AO is formed between the third sealing shoulder 23 and the hole wall of the mounting hole. The gap AO is located between the first working oil passage 12 and an adjacent part of the oil return passage 14; a gap BO is formed between the fourth sealing shoulder 24 and the hole wall of the mounting hole. The gap BO is located between the second working oil passage 13 and an adjacent part of the oil return passage 14.

[0041] As a preferred technical solution of this embodiment, the outer diameters of the first sealing shoulder 21, the second sealing shoulder 22, the third sealing shoulder 23 and the fourth sealing shoulder 24 are the same. The aperture of the mounting hole is constant, so the sizes of the gap AI, the gap BI, the gap AO and the gap BO are the same.

[0042] As a preferred technical solution of this embodiment, when the spool 2 is in the middle position, the covering amount of the gap AI is greater than that of the gap BI.

[0043] As a preferred technical solution of this embodiment, when the spool 2 is in the middle position, the covering amount of the gap BO is greater than that of the gap AO.

[0044] As a preferred technical solution of this embodiment, when the spool 2 is in the middle position, the covering amount of the gap AI is greater than that of the gap AO, and the covering amount of the gap BI is less than that of the gap BO. Further preferably, the covering amount of the gap AI is equal to that of the gap BO, and the covering amount of the gap AO is equal to that of the gap BI.

[0045] This embodiment also provides a hydraulic device, including the aforementioned valve structure and an actuator 3. The actuator 3 can be set as an oil cylinder, including a cylinder block 31 and a telescopic rod 32. The actuator 3 is communicated with the working oil ports A and B. The valve structure controls the oil to enter the actuator 3, and further controls the operation of the actuator 3. Specifically, the inside of the actuator 3 is partitioned into a rodless chamber 33 and a rod chamber 34. The working oil port A is communicated with the rodless chamber 33, and the working oil port B is communicated with the rod chamber 34.

[0046] As Figure 5 shown, assuming that the covering amounts of the gaps AI and BO are the same, both being (L + ΔL), and assuming that the covering amounts of the gaps AO and BI are the same, both being L. During the operation of the hydraulic device, the factors affecting leakage include the clearance fit, covering amount, spool diameter, and pressure difference at both ends of the gap. The formula for calculating the gap flow rate of the concentric circular ring gap pressure difference flow is as follows:

[0047]

[0048] Among them, q p represents the leakage amount of the pressure difference flow; S represents the spool diameter; h represents the clearance fit, that is, the difference between the spool hole and the spool radius; μ represents the fluid dynamic viscosity; L represents the covering amount; ΔP represents the pressure difference at both ends of the gap, that is, the pressure difference at both ends of the gap.

[0049] According to the above formula, the analysis process is as follows: Assume that when the spool 2 is in the middle position, the actuator 3 is in a balanced state and does not expand or contract. Then the flow rates entering the working oil ports A and B are 0. Therefore, the flow rates leaking through the gaps AI and AO are equal, and the flow rates leaking through the gaps BI and BO are equal.

[0050] The flow rate Q AI leaking through the gap AI is:

[0051]

[0052] Among them, S represents the spool diameter; h represents the clearance fit, that is, the difference between the spool hole and the spool radius; μ represents the dynamic viscosity of the fluid; (L + ΔL) represents the covering amount of the clearance AI; PO represents the pressure of the pressure oil passage; PA represents the pressure of the rodless cavity 33 of the actuator 3; (PO - PA) represents the pressure difference across the clearance AI.

[0053] The flow rate Q leaking through the clearance AO AO is:

[0054]

[0055] Among them, S represents the spool diameter; h represents the clearance fit, that is, the difference between the spool hole and the spool radius; μ represents the dynamic viscosity of the fluid; L represents the covering amount of the clearance AO; PA represents the pressure of the rodless cavity 33 of the actuator 3; PT represents the return oil pressure; (PA - PT) represents the pressure difference across the clearance AO.

[0056] The flow rate Q leaking through the clearance BI BI is:

[0057]

[0058] Among them, S represents the spool diameter; h represents the clearance fit, that is, the difference between the spool hole and the spool radius; μ represents the dynamic viscosity of the fluid; L represents the covering amount of the clearance BI; PO represents the pressure of the pressure oil passage; PB represents the pressure of the rod cavity 34 of the actuator 3; (PO - PB) represents the pressure difference across the clearance BI.

[0059] The flow rate Q leaking through the clearance BO BO is:

[0060]

[0061] Among them, S represents the spool diameter; h represents the clearance fit, that is, the difference between the spool hole and the spool radius; μ represents the dynamic viscosity of the fluid; (L + ΔL) represents the covering amount of the clearance AI; PB represents the pressure of the rod cavity 34 of the actuator 3; PT represents the return oil pressure; (PB - PT) represents the pressure difference across the clearance BO.

[0062] Assume that the oil cylinder does not extend, then the flow rates entering the working oil ports A and B are both 0, and the flow rates leaking through the clearances AI and AO are equal, Q AI = Q AO That is:

[0063]

[0064] It can be deduced that:

[0065]

[0066] Among them, PO represents the pressure of the pressure oil passage; PT represents the oil return pressure; L represents the covering amount of the clearance AO; (L + ΔL) represents the covering amount of the clearance AI; ΔL represents the additional covering amount of the clearance AI compared to the clearance AO.

[0067] The flow rates leaking through the clearances BI and BO are equal, Q BI = Q BO , that is:

[0068]

[0069] It can be deduced that:

[0070]

[0071] Among them, PO represents the pressure of the pressure oil passage; PT represents the oil return pressure; L represents the covering amount of the clearance BI; (L + ΔL) represents the covering amount of the clearance BO; ΔL represents the additional covering amount of the clearance BO compared to the clearance BI.

[0072] Assume that the telescopic rod 32 of the actuator 3 does not extend. From the perspective of force, the telescopic rod 32 is subjected to equal oil pressure forces in the rodless chamber 33 and the rod chamber 34, that is:

[0073]

[0074] Among them, D represents the cylinder diameter of the cylinder block 31 of the actuator 3; d represents the rod diameter of the telescopic rod 32 of the actuator 3.

[0075] From the above formula, it can be deduced that:

[0076]

[0077] Then, according to the expressions of PA and PB obtained previously, it can be obtained that:

[0078]

[0079] In the actual use process, the oil return oil passage is connected to the fuel tank T, and its oil pressure is very low and can be ignored. Therefore, let PT = 0, then the above formula can be simplified to:

[0080]

[0081] The above formula gives the relationship between the covering amount and the cylinder diameter and rod diameter of the actuator. By adjusting the specific relationship of the covering amount, the force balance of the actuator can be achieved, and there will be no automatic telescoping.

[0082] For the hydraulic device of this embodiment, by adjusting the specific relationship of the covering amount, the telescopic rod of the actuator 3 can always be in force balance in the neutral state, and there will be no problem of automatic telescoping.

[0083] The embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the present utility model is not limited to the above embodiments, and various changes can be made without departing from the gist of the present utility model within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A valve structure, characterized in that, Comprising: A valve body (1), within which a pressure oil passage (11), a first working oil passage (12), a second working oil passage (13) and an oil return passage (14) are provided; A spool (2), which is slidably assembled in the valve body (1) and slidably controls the on-off of the oil passages; When the spool (2) is in the middle position, a gap AI is formed between the spool (2) and the valve body (1) between the pressure oil passage (11) and the first working oil passage (12), a gap BI is formed between the spool (2) and the valve body (1) between the pressure oil passage (11) and the second working oil passage (13), a gap AO is formed between the spool (2) and the valve body (1) between the first working oil passage (12) and the oil return passage (14), and a gap BO is formed between the spool (2) and the valve body (1) between the second working oil passage (13) and the oil return passage (14). The covering amount of the gap AI is greater than that of the gap BI, and the covering amount of the gap BO is greater than that of the gap AO.

2. The valve structure according to claim 1, wherein, The covering amount of the gap AI is equal to that of the gap BO, and the covering amount of the gap AO is equal to that of the gap BI.

3. A valve structure according to claim 1, characterized in that, The pressure oil passage (11) includes a main oil passage (111) and two branch oil passages that are connected. The two branch oil passages are respectively a first branch oil passage (112) and a second branch oil passage (113). The two branch oil passages are respectively located on both sides of the main oil passage (111). The first working oil passage (12) and the second working oil passage (13) are located on both sides of the two branch oil passages. The first branch oil passage (112) is arranged close to the first working oil passage (12). The gap AI is located between the first branch oil passage (112) and the first working oil passage (12), and the gap BI is located between the second branch oil passage (113) and the second working oil passage (13).

4. A valve structure according to claim 2, characterized in that, The oil return passage (14) extends to both sides of the first working oil passage (12) and the second working oil passage (13). The gap AO is located between the first working oil passage (12) and an adjacent part of the oil return passage (14), and the gap BO is located between the second working oil passage (13) and an adjacent part of the oil return passage (14).

5. A valve structure according to claim 1, characterized in that, On the spool (2), a first sealing shoulder (21), a second sealing shoulder (22), a third sealing shoulder (23) and a fourth sealing shoulder (24) are formed. When in the middle position, the gap AI is formed between the first sealing shoulder (21) and the hole wall of the mounting hole of the valve body (1), the gap BI is formed between the second sealing shoulder (22) and the hole wall of the mounting hole of the valve body (1), the gap AO is formed between the third sealing shoulder (23) and the hole wall of the mounting hole of the valve body (1), and the gap BO is formed between the fourth sealing shoulder (24) and the hole wall of the mounting hole of the valve body (1).

6. A valve structure according to claim 5, characterized in that, The gap AI, the gap BI, the gap AO and the gap BO are of the same size.

7. A hydraulic device, characterized in that, Comprising: The valve structure according to claim 2, Actuator (3), the actuator (3) includes a cylinder block (31) and a telescopic rod (32), the first working oil passage (12) communicates with the rodless cavity (33) of the actuator (3), and the second working oil passage (13) communicates with the rod chamber (34) of the actuator (3).

8. A hydraulic device according to claim 7, characterized in that, The covering amount of the gap AO is L, and the covering amount of the gap AI is (L + ΔL), then where d is the rod diameter of the telescopic rod (32) of the actuator (3), and D is the cylinder diameter of the cylinder block (31) of the actuator (3).

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