Two-way proportional overflow valve

Abstract

The invention belongs to the technical field of valves, and discloses a two-way proportional overflow valve which comprises a main valve sleeve, a pilot valve sleeve assembly, a main valve element, an elastic assembly, a pilot valve element and an electromagnetic assembly, a first oil port, a second oil port and an oil discharge port are formed in the main valve sleeve, and a first cavity is formed between the main valve element and the pilot valve sleeve assembly; the main valve element is provided with a first damping channel communicating with the first oil port and the first cavity and a second damping channel communicating with the second oil port and the first cavity, a first plugging piece is arranged in the first damping channel and used for enabling a medium to flow to the first cavity from the first oil port in a one-way mode, and a second plugging piece is arranged in the second damping channel and used for enabling the medium to flow to the second cavity from the second oil port in a one-way mode. And the second plugging piece is used for enabling the medium to unidirectionally flow to the first cavity from the second oil port. The two-way proportional overflow valve can replace the integrated state of two groups of overflow valves, space and cost are saved, reverse cut-off of the other damping channel can be achieved on the basis that overflow is completed through one damping channel, and normal work of the overflow valve is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and in particular to a two-way proportional relief valve. Background Art

[0002] A relief valve controls pressure by adjusting the size of the relief port. When the fluid pressure exceeds the set pressure, the valve core will open to relieve the pressure, so that the high pressure is unloaded. A proportional relief valve adjusts the pressure by adjusting the magnitude of the control current, and can precisely control the change of the system pressure. When the system pressure reaches the set value, the proportional relief valve opens, allowing part of the oil to directly return to the fuel tank from the outlet of the pump, thereby limiting the maximum pressure of the system, ensuring the stable operation of the system, preventing damage to system components due to excessive pressure, and being applicable to the hydraulic systems of construction machinery in fields such as agriculture, industry, construction, and ships.

[0003] In construction machinery, for example, the start and stop of a crane or the forward and reverse rotations of an excavator motor are relatively frequent, and there should be no large pressure shocks during start, stop, or the forward or reverse rotation of the motor. Therefore, a relief valve is generally provided to prevent overload. However, during start, stop, or the forward and reverse rotations of the motor, both directions are involved. Therefore, in the prior art, generally two sets of relief valves are used to separately achieve high-pressure unloading in two directions. However, the volume of the two sets of relief valves is relatively large and the cost is relatively high, so it is not very suitable for widespread use in small machinery.

[0004] Therefore, there is an urgent need to provide a two-way proportional relief valve to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a two-way proportional relief valve, which can replace the integrated state of two sets of relief valves, saving space and cost.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A two-way proportional relief valve, comprising:

[0008] A main valve sleeve, which is provided with a first oil port, a second oil port, and an oil discharge port;

[0009] A pilot valve sleeve assembly, connected to one end of the main valve sleeve;

[0010] The main spool valve is slidably arranged in the main valve sleeve to conduct or cut off the first oil port and the second oil port. A first chamber is formed between the main spool valve and the pilot valve sleeve assembly. The main spool valve is provided with a first damping channel communicating the first oil port and the first chamber and a second damping channel communicating the second oil port and the first chamber. A first blocking member is arranged in the first damping channel, and the first blocking member is used to make the medium flow unidirectionally from the first oil port to the first chamber. A second blocking member is arranged in the second damping channel, and the second blocking member is used to make the medium flow unidirectionally from the second oil port to the first chamber;

[0011] An elastic component is abutted between the pilot valve sleeve assembly and the main spool valve;

[0012] The pilot spool valve is slidably arranged in the pilot valve sleeve assembly to conduct or cut off the first chamber and the oil discharge port;

[0013] An electromagnetic component is sleeved outside the pilot valve sleeve assembly and the main valve sleeve and can drive the pilot spool valve to cut off the first chamber and the oil discharge port.

[0014] As an optional scheme, the first damping channel includes a first damping hole and a second damping hole. The first damping hole extends along the axial direction of the main spool valve and includes a first small-diameter section and a first large-diameter section that are coaxially communicated. The first small-diameter section is communicated with the first oil port. The second damping hole is communicated with the first chamber and is eccentrically communicated with the first large-diameter section. The first blocking member is arranged in the first large-diameter section and is used to open or block the first small-diameter section.

[0015] As an optional scheme, a first blocking piece is fixed inside one end of the first large-diameter section, and the first blocking member can abut against the first blocking piece when opening the first small-diameter section.

[0016] As an optional scheme, the second damping channel includes a third damping hole and a fourth damping hole. The third damping hole extends along the axial direction of the main spool valve and includes a second small-diameter section and a second large-diameter section that are coaxially communicated. The second small-diameter section is communicated with the second oil port. The fourth damping hole is communicated with the first chamber and is eccentrically communicated with the second large-diameter section. The second blocking member is arranged in the second large-diameter section and is used to open or block the second small-diameter section.

[0017] As an optional scheme, a second blocking piece is fixed inside one end of the second large-diameter section, and the second blocking member can abut against the second blocking piece when opening the second small-diameter section.

[0018] As an alternative, the elastic component is arranged in the first chamber. The elastic component includes a return spring and a spring seat. The spring seat is axially limited within the pilot valve sleeve assembly. One end of the return spring abuts against the main valve core, and the other end abuts against the spring seat. The spring seat is provided with a fifth damping hole axially penetrating therethrough.

[0019] As an alternative, the first chamber communicates with the oil drain port through an oil drain channel. An oil drain hole is provided on the side wall of the pilot valve sleeve assembly. A first oil drain gap is formed between the outer peripheral side of the pilot valve sleeve assembly and the electromagnetic component, and a second oil drain gap is formed between the outer peripheral side of the main valve sleeve and the electromagnetic component. The oil drain hole, the first oil drain gap, and the second oil drain gap are sequentially communicated to form the oil drain channel.

[0020] As an alternative, a second chamber is formed between one end of the pilot valve sleeve assembly away from the main valve sleeve and the electromagnetic component. The pilot valve core is provided with a sixth damping hole, and the sixth damping hole communicates the first chamber and the second chamber.

[0021] As an alternative, the pilot valve sleeve assembly includes an armature, a valve sleeve assembly, and a valve seat. The armature is inserted into one end of the main valve sleeve. The valve sleeve assembly and the valve seat are fixedly disposed through the armature. The pilot valve core slides through the valve sleeve assembly. A communication hole communicating the first chamber and the oil drain port is provided in the valve seat. The pilot valve core is used to open or block the communication hole.

[0022] As an alternative, the pilot valve sleeve assembly includes an armature and a valve sleeve assembly. The armature is inserted into one end of the main valve sleeve. The valve sleeve assembly is fixed within the armature. The pilot valve core slides through the valve sleeve assembly. A communication hole communicating the first chamber and the oil drain port is provided in the armature. The pilot valve core is used to open or block the communication hole.

[0023] Advantages of the present invention:

[0024] The present invention provides a two-way proportional overflow valve. Through ingenious setting and connection of the structure, the pressure overflow buffering function in two directions from the first oil port to the second oil port or from the second oil port to the first oil port is realized. One overflow valve can be applicable to two different working conditions, and can replace the integrated state of two groups of overflow valves. Compared with the prior art, the cumbersome problems of arrangement and pipeline connection caused by the connection of two valve bodies are reduced, the structure is more compact, space and cost are saved, and on the basis of realizing overflow buffering through one damping channel, reverse cutoff of the other damping channel can be realized, thereby avoiding the occurrence of liquid flow disorder and affecting the unloading function, and ensuring the normal operation of the overflow valve. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of a two-way proportional overflow valve provided by an embodiment of the present invention;

[0026] Figure 2 is a cross-sectional view of a two-way proportional overflow valve provided by an optional embodiment of the present invention;

[0027] Figure 3 is a cross-sectional view of a two-way proportional overflow valve provided by another optional embodiment of the present invention;

[0028] Figure 4 is a schematic structural diagram of a main spool provided by an embodiment of the present invention;

[0029] Figure 5 is Figure 4 a cross-sectional view at A-A in;

[0030] Figure 6 is Figure 4 a cross-sectional view at B-B in.

[0031] In the figure:

[0032] 1. Main valve sleeve; 11. First oil port; 12. Second oil port; 13. Drain port;

[0033] 2. Pilot valve sleeve assembly; 21. Stop iron; 22. Valve kit; 23. Valve seat; 24. Communication hole;

[0034] 3. Main spool; 31. First damping channel; 311. First damping hole; 3111. First small-diameter section; 3112. First large-diameter section; 312. Second damping hole; 32. Second damping channel; 321. Third damping hole; 3211. Second small-diameter section; 3212. Second large-diameter section; 322. Fourth damping hole; 33. First plugging member; 34. Second plugging member; 35. First blocking member; 36. Second blocking member;

[0035] 4. Elastic component; 41. Return spring; 42. Spring seat; 421. Fifth damping hole;

[0036] 5. Pilot spool; 51. Sixth damping hole;

[0037] 6. Electromagnetic component; 61. Magnetic conducting sleeve; 611. Tail collar; 612. Magnetic isolation tube; 613. Front collar; 62. Coil; 63. Moving iron; 631. First diversion hole; 632. Second diversion hole; 64. Locking nut; 65. Third plugging member;

[0038] X1. First chamber; X2. Second chamber; c1. Drain hole; c2. First drain gap; c3. Second drain gap. Detailed implementation manners

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of convenience of description, only the parts related to the present invention rather than all the structures are shown in the drawings.

[0040] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0042] In the description of this embodiment, the orientation or positional relationships such as "up", "down", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meanings.

[0043] Such as Figure 1 and Figure 2As shown in the figure, this embodiment provides a two-way proportional overflow valve, which includes a main valve sleeve 1, a pilot valve sleeve assembly 2, a main spool 3, an elastic assembly 4, a pilot spool 5, and an electromagnetic assembly 6. The main valve sleeve 1 is provided with a first oil port 11, a second oil port 12, and a drain port 13. One of the first oil port 11 and the second oil port 12 is an oil inlet, and the other is an oil return port. Through different states in the hydraulic system, such as the forward and reverse rotation states of an excavator motor, the oil inlet and outlet states of the first oil port 11 and the second oil port 12 can be switched. The drain port 13 is used to connect to the fuel tank. The pilot valve sleeve assembly 2 is connected to one end of the main valve sleeve 1. The main spool 3 is configured in the form of a stepped shaft and is slidably arranged in the main valve sleeve 1 to conduct or cut off the first oil port 11 and the second oil port 12. A first chamber X1 is formed between the main spool 3 and the pilot valve sleeve assembly 2. The main spool 3 is provided with a first damping channel 31 communicating the first oil port 11 and the first chamber X1 and a second damping channel 32 communicating the second oil port 12 and the first chamber X1. A first plugging member 33 is arranged in the first damping channel 31, and the first plugging member 33 is used to make the medium (hydraulic oil) flow unidirectionally from the first oil port 11 to the first chamber X1. A second plugging member 34 is arranged in the second damping channel 32, and the second plugging member 34 is used to make the medium flow unidirectionally from the second oil port 12 to the first chamber X1. The elastic assembly 4 abuts between the pilot valve sleeve assembly 2 and the main spool 3. The pilot spool 5 is slidably arranged in the pilot valve sleeve assembly 2 to conduct or cut off the first chamber X1 and the drain port 13. The electromagnetic assembly 6 is sleeved outside the pilot valve sleeve assembly 2 and the main valve sleeve 1 and can drive the pilot spool 5 to cut off the first chamber X1 and the drain port 13.

[0044] Among them, "slidably arranged" means that there is a certain gap between the main spool 3 and the main valve sleeve 1, and at the same time, relative sealing is maintained between the main spool 3 and the main valve sleeve 1. The main spool 3 is guided and slidably mated along the inner wall of the main spool 3, and there is a certain gap between the pilot spool 5 and the pilot valve sleeve assembly 2, and at the same time, relative sealing is maintained between the pilot spool 5 and the pilot valve sleeve. The pilot spool 5 is guided and slidably mated along the inner wall of the pilot valve sleeve assembly 2.

[0045] When the first oil port 11 is the oil inlet and the second oil port 12 is the oil return port, high-pressure oil enters from the first oil port 11, and the pressure acts on the right end face of the main spool 3. At the same time, the high-pressure oil pushes open the first plugging member 33 through the first damping channel 31 on the main spool 3, so that the oil flows into the first chamber X1 from the first damping channel 31, and the hydraulic pressure acts on the right end face of the pilot spool 5. When the electromagnetic assembly 6 is energized, it pushes to the right and acts on the left end face of the pilot spool 5. As the oil pressure increases, when the hydraulic pressure acting on the right end of the pilot spool 5 is greater than the electromagnetic force on the left end, the pilot spool 5 moves to the left against the electromagnetic force, so that the first chamber X1 is communicated with the oil discharge port 13, and the hydraulic oil in the first chamber X1 flows out through the oil discharge port 13 for unloading. Due to the damping effect of the first damping channel 31, the hydraulic oil at the first oil port 11 cannot quickly reach the first chamber X1. Therefore, a pressure difference is formed between the left and right ends of the main spool 3 at this time. The main spool 3 moves to the left against the action force of the elastic assembly 4 under the drive of the pressure difference, so that the first oil port 11 and the second oil port 12 are communicated, and the hydraulic oil flows from the first oil port 11 to the second oil port 12 for high-pressure unloading. During this process, the second plugging member 34 will block the second damping channel 32 under the action of the oil pressure in the first chamber X1, realizing the reverse cut-off of the second damping channel 32, avoiding the reverse flow of the hydraulic oil in the first chamber X1 through the second damping channel 32 to the second oil port 12 and affecting the oil pressure in the first chamber X1, thereby avoiding the occurrence of liquid flow disorder and affecting the unloading function, and ensuring the normal operation of the relief valve.

[0046] After the above unloading action is completed, the current is increased so that the electromagnetic force acting on the left end face of the pilot spool 5 is greater than the hydraulic pressure on the right end of the pilot spool 5. The pilot spool 5 moves to the right against the hydraulic pressure, so that the first chamber X1 is cut off from the oil discharge port 13, and the oil pressure in the first chamber X1 gradually increases. When the sum of the hydraulic pressure acting on the left end of the main spool 3 and the elastic force of the elastic assembly 4 is greater than the hydraulic pressure on the right end of the main spool 3, the main spool 3 moves to the right under the drive of the pressure difference, so that the first oil port 11 and the second oil port 12 are cut off.

[0047] Similarly, when the second oil port 12 is the oil inlet and the first oil port 11 is the oil return port, high-pressure oil enters from the second oil port 12, and the pressure acts on the stepped surface on the right side of the main spool 3. At the same time, the high-pressure oil pushes open the second plugging member 34 through the second damping channel 32 on the main spool 3, so that the oil flows into the first chamber X1 from the second damping channel 32, and the hydraulic pressure acts on the right end surface of the pilot spool 5. When the electromagnetic assembly 6 is energized, it pushes and acts on the left end surface of the pilot spool 5. As the oil pressure increases, when the hydraulic pressure acting on the right end of the pilot spool 5 is greater than the electromagnetic force on the left end, the pilot spool 5 moves to the left against the electromagnetic force, so that the first chamber X1 is communicated with the oil discharge port 13, and the hydraulic oil in the first chamber X1 flows out through the oil discharge port 13. Due to the damping effect of the second damping channel 32, the hydraulic oil at the second oil port 12 cannot quickly reach the first chamber X1. Therefore, a pressure difference is formed between the left and right ends of the main spool 3 at this time. The main spool 3 moves to the left against the action force of the elastic assembly 4 under the drive of the pressure difference, so that the second oil port 12 and the first oil port 11 are communicated, and the hydraulic oil flows from the second oil port 12 to the first oil port 11 for high-pressure unloading. During this process, the first plugging member 33 will block the first damping channel 31 under the action of the oil pressure in the first chamber X1, realizing the reverse cut-off of the first damping channel 31, avoiding the reverse flow of the hydraulic oil in the first chamber X1 through the first damping channel 31 to the first oil port 11 and affecting the oil pressure in the first chamber X1, thereby avoiding the occurrence of liquid flow disorder and affecting the unloading function, and ensuring the normal operation of the relief valve.

[0048] After the above unloading action is completed, the current is increased so that the electromagnetic force acting on the left end surface of the pilot spool 5 is greater than the hydraulic pressure on the right end of the pilot spool 5. The pilot spool 5 moves to the right against the hydraulic pressure, so that the first chamber X1 is cut off from the oil discharge port 13, and the oil pressure in the first chamber X1 gradually increases. When the sum of the hydraulic pressure acting on the left end of the main spool 3 and the elastic force of the elastic assembly 4 is greater than the hydraulic pressure on the right end of the main spool 3, the main spool 3 moves to the right under the drive of the pressure difference, so that the second oil port 12 and the first oil port 11 are cut off.

[0049] It can be seen that the two-way proportional relief valve provided in this embodiment realizes the pressure overflow buffering function in two directions from the first oil port 11 to the second oil port 12 or from the second oil port 12 to the first oil port 11 through ingenious setting and connection of the structure. One relief valve can be applied to two different working conditions, such as the starting and braking states of a crane or the forward and reverse rotation states of an excavator motor. It can replace the integrated state of two relief valves. Compared with the prior art, it reduces the cumbersome problems of layout and pipeline connection caused by the connection of two valve bodies, has a more compact structure, saves space and cost, and can realize the reverse cut-off of another damping channel on the basis of completing the overflow buffering through one of the damping channels, thereby avoiding the occurrence of liquid flow disorder and affecting the unloading function, and ensuring the normal operation of the relief valve.

[0050] Specifically, as Figure 4 and Figure 5 shown, the first damping passage 31 includes a first damping hole 311 and a second damping hole 312. The first damping hole 311 extends along the axial direction of the main spool 3 and includes a first small-diameter section 3111 and a first large-diameter section 3112 that are coaxially connected. The first small-diameter section 3111 is connected to the first oil port 11. The second damping hole 312 is connected to the first chamber X1 and is eccentrically connected to the first large-diameter section 3112. The first plugging member 33 is slidably disposed in the first large-diameter section 3112 and is used to open or block the first small-diameter section 3111. When the first plugging member 33 opens the first small-diameter section 3111 under the action of oil pressure, the first small-diameter section 3111 is sequentially connected to the first chamber X1 through the first large-diameter section 3112 and the second damping hole 312.

[0051] Similarly, as Figure 4 and Figure 6 shown, the second damping passage 32 includes a third damping hole 321 and a fourth damping hole 322. The third damping hole 321 extends along the axial direction of the main spool 3 and includes a second small-diameter section 3211 and a second large-diameter section 3212 that are coaxially connected. The second small-diameter section 3211 is connected to the second oil port 12. The fourth damping hole 322 is connected to the first chamber X1 and is eccentrically connected to the second large-diameter section 3212. The second plugging member 34 is slidably disposed in the second large-diameter section 3212 and is used to open or block the second small-diameter section 3211. When the second plugging member 34 opens the second small-diameter section 3211 under the action of oil pressure, the second small-diameter section 3211 is sequentially connected to the first chamber X1 through the second large-diameter section 3212 and the fourth damping hole 322.

[0052] When the first oil port 11 is the oil inlet and the second oil port 12 is the oil return port, high-pressure oil enters from the first oil port 11, then flows into the first small-diameter section 3111 and pushes the first plugging member 33 away, opening the first small-diameter section 3111. At this time, the hydraulic oil sequentially flows into the first chamber X1 through the first small-diameter section 3111, the first large-diameter section 3112, and the second damping hole 312, gradually building up oil pressure in the first chamber X1. During this process, the second plugging member 34 will block the second small-diameter section 3211 under the oil pressure in the first chamber X1, achieving the cutoff between the second small-diameter section 3211 and the second large-diameter section 3212, thereby realizing the reverse cutoff of the second damping passage 32, preventing the hydraulic oil in the first chamber X1 from flowing back to the second oil port 12 through the second damping passage 32 and affecting the oil pressure in the first chamber X1, and thus avoiding the occurrence of fluid flow disorder and affecting the unloading function, ensuring the normal operation of this relief valve.

[0053] Similarly, when the second oil port 12 is the oil inlet and the first oil port 11 is the oil return port, high-pressure oil enters from the second oil port 12, then flows into the second small-diameter section 3211 and pushes the second plugging member 34 away, opening the second small-diameter section 3211. At this time, the hydraulic oil sequentially flows through the second small-diameter section 3211, the second large-diameter section 3212, and the fourth damping hole 322 into the first chamber X1, gradually building up oil pressure in the first chamber X1. During this process, the first plugging member 33 will block the first small-diameter section 3111 under the oil pressure in the first chamber X1, achieving the cut-off between the first small-diameter section 3111 and the first large-diameter section 3112, thereby realizing the reverse cut-off of the first damping channel 31, preventing the hydraulic oil in the first chamber X1 from flowing reversely through the first damping channel 31 to the first oil port 11 and affecting the oil pressure in the first chamber X1, thus avoiding the occurrence of liquid flow disorder and affecting the unloading function, and ensuring the normal operation of the relief valve.

[0054] In this embodiment, the first oil port 11 is opened at one axial end of the main valve sleeve 1, the second oil port 12 and the third oil port are opened on the circumferential side of the main valve sleeve 1, the first damping hole 311 is coaxial with the main valve core 3, and the third damping hole 321 is eccentrically arranged with respect to the first damping hole 311.

[0055] In this embodiment, both the first plugging member 33 and the second plugging member 34 are spherical plugging members, and specifically, steel balls can be selected. The spherical plugging member can cooperate well with the cylindrical first small-diameter section 3111 or the second small-diameter section 3211, thereby ensuring the reliability of the sealing of the first small-diameter section 3111 or the second small-diameter section 3211, and the spherical plugging member can conveniently change its position during the dynamic process. In other alternative embodiments, the first plugging member 33 and the second plugging member 34 can also be conical, frustum-shaped, or conical-top cylindrical, etc.

[0056] Furthermore, as Figures 4 to 6 shown, in order to facilitate the installation of the first plugging member 33, one end of the first large-diameter section 3112 away from the first small-diameter section 3111 penetrates through the end of the main valve core 3. Therefore, in order to prevent the first plugging member 33 from being ejected from the first large-diameter section 3112 under the action of oil pressure, a first blocking member 35 is fixed inside the end of the first large-diameter section 3112 away from the first small-diameter section 3111. The first plugging member 33 can abut against the first blocking member 35 when opening the first small-diameter section 3111 to limit the first plugging member 33.

[0057] Similarly, for the convenience of installing the second plugging member 34, one end of the second large-diameter section 3212 away from the second small-diameter section 3211 penetrates through the end of the main spool 3. Therefore, in order to prevent the second plugging member 34 from being disengaged from the second large-diameter section 3212 under the action of oil pressure, a second blocking member 36 is fixed inside one end of the second large-diameter section 3212 away from the second small-diameter section 3211. The second plugging member 34 can abut against the second blocking member 36 when opening the second small-diameter section 3211 to limit the second plugging member 34.

[0058] It should be noted that the first blocking member 35 is a combination of a cylinder and a frustum of a cone. The cylindrical part can be fixed inside the first large-diameter section 3112 by interference fit, gluing, etc. The frustum part can make the first blocking member 35 be assembled inside the first large-diameter section 3112 more quickly and conveniently. And the plane of the frustum part contacts the spherical first plugging member 33, which is more stable and reliable and can avoid damage to structural parts. The second blocking member 36 is exactly the same as the first blocking member 35, so it will not be elaborated here.

[0059] As Figure 2 shown, the elastic component 4 is arranged in the first chamber X1. The elastic component 4 includes a return spring 41 and a spring seat 42. The spring seat 42 is axially limited inside the pilot valve sleeve assembly 2. One end of the return spring 41 abuts against the main spool 3, and the other end abuts against the spring seat 42. Most of the return spring 41 is located inside the pilot valve sleeve assembly 2, which can shorten the overall length of the overflow valve to a certain extent. The return spring 41 is configured to always have a tendency to prevent the main spool 3 from moving relative to the valve sleeve to conduct the first oil port 11 and the second oil port 12. When there is no pressure difference between the left and right ends of the main spool 3, it can ensure that the main spool 3 is in the plugging position, thus ensuring the reliability of the overflow valve.

[0060] Furthermore, as Figure 2 shown, the spring seat 42 is a plate-like structure and divides the first chamber X1 into two parts. A fifth damping hole 421 axially penetrating is opened at the center of the spring seat 42. When the hydraulic oil enters through the first damping channel 31 or the second damping channel 32, it enters the first chamber X1 on its left side through the fifth damping hole 421. The hydraulic pressure acts on the left end face of the pilot spool 5. When the hydraulic oil is depressurized through the oil discharge port 13, during this process, due to the damping effect of the fifth damping hole 421, the hydraulic oil cannot reach the first chamber X1 quickly, so the impact on the pilot spool 5 can be reduced.

[0061] As Figure 2As shown, in an alternative embodiment, the pilot valve sleeve assembly 2 includes a stop iron 21, a valve sleeve set 22, and a valve seat 23. The stop iron 21 is threadedly inserted into one end of the main valve sleeve 1. The valve sleeve set 22 and the valve seat 23 are fixedly inserted through the stop iron 21. The valve sleeve set 22 is fixed in the stop iron 21 by a circlip. The pilot valve core 5 slides through the valve sleeve set 22. A communication hole 24 communicating the first chamber X1 and the oil discharge port 13 is provided in the valve seat 23. The pilot valve core 5 is used to open or block the communication hole 24. Among them, the pilot valve core 5 is a conical valve core. The sealing surface of the conical valve core contacts the orifice of the communication hole 24 to form a seal. The sealing surface is a line contact seal formed by an annular line and a conical surface, and the sealing effect is good.

[0062] As Figure 3 shown, in another alternative embodiment, the valve seat 23 and the stop iron 21 can also be integrated into one part to reduce the assembly process, that is, the pilot valve sleeve assembly 2 includes a stop iron 21 and a valve sleeve set 22. The stop iron 21 is threadedly inserted into one end of the main valve sleeve 1. The valve sleeve set 22 is fixedly inserted through the stop iron 21 by a circlip. The pilot valve core 5 slides through the valve sleeve set 22. A communication hole 24 communicating the first chamber X1 and the oil discharge port 13 is provided in the stop iron 21. The pilot valve core � is used to open or block the communication hole 24.

[0063] Further, as Figure 2 shown, the first chamber X1 is communicated with the oil discharge port 13 through an oil discharge channel. An oil discharge hole c1 is provided on the side wall of the stop iron 21 of the pilot valve sleeve assembly 2. A first oil discharge gap c2 is formed between the outer peripheral side of the stop iron 21 and the electromagnetic assembly 6. A second oil discharge gap c3 is formed between the outer peripheral side of the main valve sleeve 1 and the electromagnetic assembly 6. The oil discharge hole c1, the first oil discharge gap c2, and the second oil discharge gap c3 are sequentially communicated to form an oil discharge channel. After the pilot valve core 5 moves to the left, the communication hole 24 is opened. At this time, the first chamber X1 is communicated with the oil discharge hole c1 through the communication hole 24. The hydraulic oil in the first chamber X1 sequentially passes through the communication hole 24, the oil discharge hole c1, the first oil discharge gap c2, and the second oil discharge gap c3, and finally flows out from the oil discharge port 13 to unload the pressure in the first chamber X1.

[0064] As Figure 2 shown, the electromagnetic assembly 6 includes a magnetic conductive sleeve 61, a coil 62, and an armature 63. The magnetic conductive sleeve 61 is sleeved outside the stop iron 21 and one end of the main valve sleeve 1. The coil 62 is sleeved on the outer periphery of the magnetic conductive sleeve 61. The armature 63 is inserted through the magnetic conductive sleeve 61, and the armature 63 and the stop iron 21 are arranged at intervals along the axial direction of the magnetic conductive sleeve 61. The armature 63 can move to the right along the axial direction of the magnetic conductive sleeve 61 under the electromagnetic force generated by the coil 62 to push the pilot valve core 5, so that the pilot valve core 5 moves to the right and blocks the communication hole 24, and the armature 63 can abut against the stop iron 21 to limit the extreme position of the armature 63 moving relative to the magnetic conductive sleeve 61 in the direction towards the pilot valve core 5 (i.e., to the right).

[0065] Further, a second chamber X2 is formed between one end of the pilot valve sleeve assembly 2 away from the main valve sleeve 1 and the armature 63 of the electromagnetic assembly 6. A sixth damping hole 51 is formed in the pilot valve core 5, and the sixth damping hole 51 communicates with the first chamber X1 and the second chamber X2. The hydraulic oil in the first chamber X1 can flow into the second chamber X2 through the sixth damping hole 51, so that the second chamber X2 forms a buffer chamber, and buffers the movement of the armature 63 and the pilot valve core 5, so that when the pilot valve core 5 moves leftward and the stop iron 21 moves rightward, they can move slowly, avoiding the problem of damage when the armature 63 and the pilot valve core 5 come into contact quickly.

[0066] Further, in combination with Figure 2 , the electromagnetic assembly 6 further includes a third plugging member 65. A first diversion hole 631 and a second diversion hole 632 are formed in the armature 63. The second diversion hole 632 axially penetrates the armature 63 and is a stepped hole. The first diversion hole 631 communicates with the second chamber X2 and the second diversion hole 632. The third plugging member 65 is located in the second diversion hole 632 near one end of the second chamber X2 and can abut against the stepped surface of the second diversion hole 632. During the process that the armature 63 moves rightward under the electromagnetic force generated by the coil 62, the hydraulic oil in the second chamber X2 can enter the second diversion hole 632 through the first diversion hole 631. A part of the hydraulic oil in the second diversion hole 632 flows leftward and acts on the left end face of the armature 63, applying a rightward acting force to the armature 63, thereby reducing the electromagnetic force when adjusting the pilot valve core 5. Another part of the hydraulic oil in the second diversion hole 632 flows rightward and acts on the third plugging member 65, so that the third plugging member 65 can abut against the left end of the pilot valve core 5 after moving rightward, closing the communication hole 24 by the pilot valve core 5. If the armature 63 directly abuts against the left end of the pilot valve core 5, it will cause an increase in the force to open the pilot valve core 5. The function of the third plugging member 65 is to adjust the air gap and can reduce the force to open the pilot valve core 5.

[0067] In this embodiment, the third plugging member 65 is a spherical plugging member, and specifically, a steel ball can be selected. The spherical plugging member can conveniently change its position during the dynamic process and has a better sealing effect. In other alternative embodiments, the third plugging member 65 can also be conical, frustum-shaped or cone-top cylindrical, etc.

[0068] Specifically, the magnetic conduction sleeve 61 includes a magnetic isolation tube 612, a tail collar 611 and a front collar 613. Among them, a coil 62 is sleeved on the outer periphery of the magnetic isolation tube 612. The tail collar 611 is welded to the inner periphery of the left end of the magnetic isolation tube 612, and the front collar 613 is welded to the outer periphery of the right end of the magnetic isolation tube 612. The magnetic isolation tube 612 is sleeved on a part of the stop iron 21, and the front collar 613 is threadedly sleeved on the left end of the main valve sleeve 1. In this embodiment, the right end of the tail collar 611 can abut against the left end of the moving iron 63, thereby restricting the extreme position of the moving iron 63 moving away from the pilot valve core 5 (i.e., moving to the left).

[0069] Furthermore, the electromagnetic assembly 6 further includes a lock nut 64. The left end of the tail collar 611 is threadedly connected with the lock nut 64. The lock nut 64 is used to press the coil 62 against the left end portion of the front collar 613, thereby preventing the coil 62 from moving axially and realizing the fixation of the coil 62 on the outer periphery of the magnetic isolation tube 612.

[0070] Combined with Figure 2 , in this embodiment, taking the forward and reverse rotation of the motor as an example, the working principle of the two-way proportional overflow valve will be described in detail:

[0071] For example, when the motor rotates forward: the first oil port 11 is the oil inlet, the second oil port 12 is the oil return port, high-pressure oil enters from the first oil port 11, and the pressure acts on the right end face of the main valve core 3. At the same time, the high-pressure oil pushes the first plug 33 open through the first small-diameter section 3111 on the main valve core 3, so that the first small-diameter section 3111 is opened. At this time, the hydraulic oil sequentially passes through the first small-diameter section 3111, the first large-diameter section 3112, the second damping hole 312 and the fifth damping hole 421 on the spring seat 42 and flows into the left-side first chamber X1, so that the oil pressure is gradually established in the first chamber X1, and the hydraulic pressure acts on the right end face of the pilot valve core 5. At the same time, the hydraulic oil in the first chamber X1 flows into the second chamber X2 through the sixth damping hole 51 on the pilot valve core 5 to form a buffer chamber. When the coil 62 is energized, the electromagnetic force generated by the coil 62 pushes the moving iron 63 to the right, and the third plug 65 acts on the left end face of the pilot valve core 5. As the oil pressure increases, when the hydraulic pressure acting on the right end of the pilot valve core 5 is greater than the electromagnetic force on the left end, the pilot valve core 5 overcomes the electromagnetic force and moves to the left to open the communication hole 24. The hydraulic oil in the first chamber X1 sequentially passes through the communication hole 24, the oil discharge hole c1, the first oil discharge gap c2 and the second oil discharge gap c3, and finally flows out from the oil discharge port 13 for unloading. Due to the damping effect of the first damping channel 31 and the fifth damping hole 421, the hydraulic oil at the first oil port 11 cannot quickly reach the first chamber X1. Therefore, a pressure difference is formed between the left and right ends of the main valve core 3. The main valve core 3 moves to the left under the drive of the pressure difference to overcome the acting force of the return spring 41, so that the first oil port 11 and the second oil port 12 are communicated, and the hydraulic oil flows from the first oil port 11 to the second oil port 12 for high-pressure unloading.

[0072] During this process, the second plugging member 34 will plug the second small-diameter section 3211 under the oil pressure of the first chamber X1, realizing the cut-off between the second small-diameter section 3211 and the second large-diameter section 3212, thereby realizing the reverse cut-off of the second damping channel 32, avoiding the hydraulic oil in the first chamber X1 from flowing reversely through the second damping channel 32 to the second oil port 12 and affecting the oil pressure in the first chamber X1, thus avoiding the occurrence of fluid flow disorder and affecting the unloading function, and ensuring the normal operation of this overflow valve.

[0073] After completing the above unloading action, increase the current to make the moving iron 63 move to the right. The third plugging member 63 pushes the pilot valve core 5 to move to the right against the hydraulic pressure, plugs the communication hole 24, cuts off the first chamber X1 from the oil discharge port 13, and the oil pressure in the first chamber X1 gradually increases. When the sum of the hydraulic pressure acting on the left end of the main valve core 3 and the elastic force of the return spring 41 is greater than the hydraulic pressure on the right end of the main valve core 3, the main valve core 3 moves to the right under the drive of the pressure difference, cutting off the first oil port 11 and the second oil port 12.

[0074] When the motor rotates reversely: The second oil port 12 is the oil inlet, and the first oil port 11 is the oil return port. High-pressure oil enters from the second oil port 12, and the pressure acts on the stepped surface on the right side of the main valve core 3. At the same time, the high-pressure oil pushes the second plugging member 34 open through the second small-diameter section 3211 on the main valve core 3, opening the second small-diameter section 3211. At this time, the hydraulic oil sequentially flows into the left first chamber X1 through the second small-diameter section 3211, the second large-diameter section 3212, the fourth damping hole 322, and the fifth damping hole 421 on the spring seat 42, enabling the first chamber X1 to gradually build up oil pressure, and the hydraulic pressure acts on the right end surface of the pilot valve core 5. At the same time, the hydraulic oil in the first chamber X1 flows into the second chamber X2 through the sixth damping hole 51 on the pilot valve core 5 to play a buffering role. When the coil 62 is energized, it pushes to the right and acts on the left end surface of the pilot valve core 5. As the oil pressure increases, the electromagnetic force generated by the coil 62 pushes the moving iron 63 to the right, and the third plugging member 63 acts on the left end surface of the pilot valve core 5. As the oil pressure increases, when the hydraulic pressure acting on the right end of the pilot valve core 5 is greater than the electromagnetic force on the left end, the pilot valve core 5 overcomes the electromagnetic force and moves to the left to open the communication hole 24. The hydraulic oil in the first chamber X1 sequentially passes through the communication hole 24, the oil discharge hole c1, the first oil discharge gap c2, and the second oil discharge gap c3, and finally flows out from the oil discharge port 13. Due to the damping effect of the second damping channel 32 and the fifth damping hole 421, the hydraulic oil at the second oil port 12 cannot quickly reach the first chamber X1. Therefore, a pressure difference is formed between the left and right ends of the main valve core 3 at this time. The main valve core 3 moves to the left under the drive of the pressure difference, overcoming the acting force of the return spring 41, connecting the second oil port 12 and the first oil port 11, and the hydraulic oil flows from the second oil port 12 to the first oil port 11 for high-pressure unloading.

[0075] In this process, the first plugging member 33 plugs the first small-diameter section 3111 under the oil pressure in the first chamber X1, achieving the cut-off between the first small-diameter section 3111 and the first large-diameter section 3112, thereby realizing the reverse cut-off of the first damping channel 31, avoiding the hydraulic oil in the first chamber X1 flowing reversely through the first damping channel 31 to the first oil port 11 and affecting the oil pressure in the first chamber X1, thus avoiding the occurrence of fluid flow disorder and affecting the unloading function, and ensuring the normal operation of this overflow valve.

[0076] After completing the above unloading action, increase the current to make the moving iron 63 move to the right. The third plugging member 65 pushes the pilot valve core 5 to move to the right against the hydraulic pressure, plugs the communication hole 24, cuts off the first chamber X1 from the oil discharge port 13, and the oil pressure in the first chamber X1 gradually increases. When the sum of the hydraulic pressure acting on the left end of the main valve core 3 and the elastic force of the return spring is greater than the hydraulic pressure on the right end of the main valve core 3, the main valve core 3 moves to the right under the drive of the pressure difference, cutting off the second oil port 12 and the first oil port 11.

[0077] Certainly, the reverse rotation of the motor can also correspond to the case where the first oil port 11 is the oil inlet and the second oil port 12 is the oil return port, and the forward rotation of the motor can correspond to the case where the first oil port 11 is the oil return port and the second oil port 12 is the oil inlet. The principle is exactly the same and will not be elaborated here.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A two-way proportional overflow valve, characterized in that, Comprising: A main valve sleeve (1) provided with a first oil port (11), a second oil port (12) and an oil drain port (13); A pilot valve sleeve assembly (2) connected to one end of the main valve sleeve (1); A main spool (3) slidably disposed within the main valve sleeve (1) to conduct or cut off the first oil port (11) and the second oil port (12). A first chamber (X1) is formed between the main spool (3) and the pilot valve sleeve assembly (2). The main spool (3) is provided with a first damping passage (31) communicating the first oil port (11) and the first chamber (X1) and a second damping passage (32) communicating the second oil port (12) and the first chamber (X1). A first blocking member (33) is provided within the first damping passage (31) for allowing the medium to flow unidirectionally from the first oil port (11) to the first chamber (X1). A second blocking member (34) is provided within the second damping passage (32) for allowing the medium to flow unidirectionally from the second oil port (12) to the first chamber (X1); An elastic component (4) abutted between the pilot valve sleeve assembly (2) and the main spool (3); A pilot spool (5) slidably disposed within the pilot valve sleeve assembly (2) to conduct or cut off the first chamber (X1) and the oil drain port (13); An electromagnetic component (6) sleeved outside the pilot valve sleeve assembly (2) and the main valve sleeve (1) and capable of driving the pilot spool (5) to cut off the first chamber (X1) and the oil drain port (13).

2. The bi-directional proportional overflow valve according to claim 1, characterized in that, The first damping passage (31) includes a first damping hole (311) and a second damping hole (312). The first damping hole (311) extends along the axial direction of the main spool (3) and includes a first small-diameter section (3111) and a first large-diameter section (3112) that are coaxially connected. The first small-diameter section (3111) communicates with the first oil port (11). The second damping hole (312) communicates with the first chamber (X1) and is eccentrically connected to the first large-diameter section (3112). The first blocking member (33) is disposed within the first large-diameter section (3112) and is used to open or block the first small-diameter section (3111).

3. The bi-directional proportional overflow valve according to claim 2, wherein A first blocking piece (35) is fixed inside one end of the first large-diameter section (3112). The first blocking member (33) can abut against the first blocking piece (35) when opening the first small-diameter section (3111).

4. The bi-directional proportional overflow valve according to claim 1, wherein, The second damping passage (32) includes a third damping hole (321) and a fourth damping hole (322). The third damping hole (321) extends along the axial direction of the main spool valve (3) and includes a second small-diameter section (3211) and a second large-diameter section (3212) that are coaxially connected. The second small-diameter section (3211) communicates with the second oil port (12). The fourth damping hole (322) communicates with the first chamber (X1) and is eccentrically connected to the second large-diameter section (3212). The second plugging member (34) is disposed in the second large-diameter section (3212) and is used to open or block the second small-diameter section (3211).

5. The bi-directional proportional overflow valve according to claim 4, characterized in that, A second blocking member (36) is fixedly installed inside one end of the second large-diameter section (3212). The second plugging member (34) can abut against the second blocking member (36) when opening the second small-diameter section (3211).

6. The bi-directional proportional overflow valve according to claim 1, characterized in that, The elastic component (4) is disposed in the first chamber (X1). The elastic component (4) includes a return spring (41) and a spring seat (42). The spring seat (42) is axially limited inside the pilot valve sleeve assembly (2). One end of the return spring (41) abuts against the main spool valve (3), and the other end abuts against the spring seat (42). A fifth damping hole (421) is axially formed through the spring seat (42).

7. The bi-directional proportional overflow valve according to claim 1, wherein The first chamber (X1) communicates with the oil drain port (13) through an oil drain passage. An oil drain hole (c1) is formed on the side wall of the pilot valve sleeve assembly (2). A first oil drain gap (c2) is formed between the outer peripheral side of the pilot valve sleeve assembly (2) and the electromagnetic component (6). A second oil drain gap (c3) is formed between the outer peripheral side of the main valve sleeve (1) and the electromagnetic component (6). The oil drain hole (c1), the first oil drain gap (c2), and the second oil drain gap (c3) are sequentially connected to form the oil drain passage.

8. The bi-directional proportional overflow valve according to claim 1, wherein A second chamber (X2) is formed between one end of the pilot valve sleeve assembly (2) away from the main valve sleeve (1) and the electromagnetic component (6). A sixth damping hole (51) is formed on the pilot spool valve (5). The sixth damping hole (51) communicates the first chamber (X1) and the second chamber (X2).

9. The bi-directional proportional overflow valve according to claim 1, wherein, The pilot valve sleeve assembly (2) includes an armature (21), a valve sleeve assembly (22), and a valve seat (23). The armature (21) is inserted into one end of the main valve sleeve (1). The valve sleeve assembly (22) and the valve seat (23) are fixedly disposed through the armature (21). The pilot spool valve (5) is slidably disposed through the valve sleeve assembly (22). A communication hole (24) that communicates the first chamber (X1) and the oil drain port (13) is formed in the valve seat (23). The pilot spool valve (5) is used to open or block the communication hole (24).

10. The bi-directional proportional overflow valve according to claim 1, wherein, The pilot valve sleeve assembly (2) includes a stop iron (21) and a valve sleeve set (22). The stop iron (21) is inserted into one end of the main valve sleeve (1), the valve sleeve set (22) is fixed inside the stop iron (21), the pilot valve core (5) slides through the valve sleeve set (22), a communication hole (24) communicating the first chamber (X1) and the oil drain port (13) is formed in the stop iron (21), and the pilot valve core (5) is used to open or block the communication hole (24).

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