Secondary buffering overflow valve and fluid control assembly

Abstract

The utility model belongs to the technical field of hydraulic valves, and discloses a two-stage buffer overflow valve and a fluid control assembly. The two-stage buffering overflow valve comprises a valve seat assembly, a valve body, a valve element mechanism, an oil passing channel and a buffering piston, the valve seat assembly is provided with an oil inlet, the valve body is arranged at the end, away from the oil inlet, of the valve seat assembly in a sleeving mode, the valve body is provided with an oil outlet, and the valve element mechanism comprises a sliding valve element arranged in the valve seat assembly in a sliding fit mode; the end, away from the oil inlet, of the sliding valve element is provided with a secondary pressure building cavity, the secondary pressure building cavity communicates with the oil inlet, at least part of the oil passing channel is arranged on the sliding valve element and / or the valve seat assembly and / or the valve body, and the oil passing channel communicates with the secondary pressure building cavity and the oil outlet; the buffer piston is arranged on the valve seat assembly in a sliding and sleeving mode and can block or open the oil outlet. By prolonging the completion time of secondary pressure establishment, the buffering effect is improved, and the impact generated when the hydraulic motor is started and braked is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic valve technical field especially relates to a two -stage buffer overflow valve and fluid control assembly. BACKGROUND

[0002] The hydraulic motor on the engineering machinery excavator can cause pressure fluctuation due to the instantaneous change of system hydraulic pressure in the process of starting and stopping because of inertia, thereby bringing greater impact to the hydraulic system, influencing the operating performance of the excavator, and generating greater work burden to the hydraulic elements in the hydraulic system. Therefore, a buffer overflow valve is usually installed in the hydraulic system to absorb the pressure pulse in the buffer system. However, the secondary pressure building time of the buffer overflow valve in the prior art is short, the buffer effect is not obvious, and the hydraulic motor still has a large impact when starting and braking.

[0003] Therefore, it is necessary to provide a two-stage buffer overflow valve and fluid control assembly to solve the above problems. SUMMARY

[0004] The utility model discloses a two-stage buffer overflow valve and fluid control assembly, which prolongs the time of establishing secondary pressure to improve the buffer effect and reduce the impact of the hydraulic motor when starting and braking.

[0005] To achieve this purpose, the utility model adopts the following technical scheme:

[0006] A two-stage buffer overflow valve comprises:

[0007] A valve seat assembly has an oil inlet, and a valve body is sleeved on one end of the valve seat assembly away from the oil inlet, and the valve body has an oil outlet;

[0008] A valve core mechanism comprises a sliding valve core slidingly fitted in the valve seat assembly, and one end of the sliding valve core away from the oil inlet has a secondary pressure building cavity, and the secondary pressure building cavity is communicated with the oil inlet;

[0009] An oil passage is at least partially arranged on the sliding valve core and / or the valve seat assembly and / or the valve body, and the oil passage is communicated with the secondary pressure building cavity and the oil outlet;

[0010] A buffer piston is slidingly sleeved on the valve seat assembly, and the buffer piston can block or open the oil outlet.

[0011] As preferred, the oil passage comprises:

[0012] A first passage is at least partially arranged on the sliding valve core, and the first passage is communicated with the secondary pressure building cavity;

[0013] a second passage formed by a gap between the spool and the valve seat assembly along a radial direction of the valve seat assembly;

[0014] a third passage at least partially provided on the valve seat assembly;

[0015] a fourth passage formed by a gap between the valve body and the valve seat assembly along a radial direction of the valve seat assembly;

[0016] a fifth passage at least partially provided on the valve body, the fifth passage being in communication with the oil outlet, and the first passage, the second passage, the third passage, the fourth passage and the fifth passage being in communication.

[0017] Preferably, the valve seat assembly comprises a regulating sleeve and a valve sleeve, one end of the regulating sleeve being connected to the valve sleeve, a wall of the second passage comprising a wall of the regulating sleeve and a wall of the spool, the spool having extreme positions comprising a first position and a second position, the first passage and the second passage being in communication from the first position to the second position, the second passage being in communication with the third passage.

[0018] Preferably, a gap between the spool and the regulating sleeve forms the second passage, and at least a part of the third passage is provided on the regulating sleeve.

[0019] Preferably, the regulating sleeve has an abutting surface, the spool mechanism being capable of abutting against the abutting surface, and the regulating sleeve being axially slidable to change the relative position of the regulating sleeve and the valve sleeve.

[0020] Preferably, the spool mechanism further comprises a cone spool, the cone spool being slidingly fitted in the valve seat assembly, the valve seat assembly further comprising a valve port and a return port, the valve port being capable of communicating the oil inlet and the return port, and the cone spool being capable of closing or opening the valve port.

[0021] Preferably, the spool mechanism further comprises an elastic assembly, two ends of the elastic assembly being connected to or abutting against the cone spool and the spool respectively.

[0022] Preferably, the elastic assembly comprises an elastic member and a support seat, the support seat being provided at an end of the elastic member, and the support seat abutting against or being connected to the cone spool and / or the spool.

[0023] Preferably, the spool is provided with a first damping hole, the cone spool is provided with a second damping hole, and the oil inlet, the second damping hole, the first damping hole and the secondary pressure building cavity are in communication in sequence.

[0024] The fluid control assembly comprises a mounting block and the two-stage buffer overflow valve, the two-stage buffer overflow valve is arranged in the mounting block, and the mounting block is provided with a limiting wall for limiting the limit position of the buffer piston moving rightwards in the axial direction.

[0025] The utility model discloses beneficial effects:

[0026] The two-stage buffer overflow valve comprises a valve seat assembly, a valve body, a valve core mechanism, an oil passing channel and a buffer piston, the valve seat assembly is provided with an oil inlet, the valve body is sleeved at one end of the valve seat assembly away from the oil inlet, the valve body is provided with an oil outlet, the valve core mechanism comprises a sliding valve core sleeved in the valve seat assembly, one end of the sliding valve core away from the oil inlet is provided with a secondary pressure building cavity, the secondary pressure building cavity is communicated with the oil inlet, at least part of the oil passing channel is arranged on the sliding valve core and / or the valve seat assembly and / or the valve body, and the oil passing channel is communicated with the secondary pressure building cavity and the oil outlet, and the buffer piston is sleeved in the valve seat assembly, and the buffer piston can block or open the oil outlet.

[0027] The hydraulic oil enters the secondary pressure building cavity through the oil inlet, the hydraulic oil pushes the sliding valve core to move rightwards to increase the pre-tightening force of the valve core mechanism, and then the secondary pressure is built. Since the secondary pressure building cavity is communicated with the oil outlet through the oil passing channel, the hydraulic oil in the secondary pressure building cavity flows to the oil outlet along the oil passing channel, and then flows out of the oil outlet to push the buffer piston to slide rightwards in the axial direction, and then the pressure in the secondary pressure building cavity slowly rises to prolong the time for the secondary pressure to be built, improve the buffer effect, reduce the impact of the hydraulic motor during starting and braking, improve the operation performance of the excavator, protect the hydraulic elements in the hydraulic system, and make the driver obtain a good driving feeling. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a sectional view of the two-stage buffer overflow valve provided by the utility model;

[0029] Figure 2 is Figure 1 a local enlarged view of A in Fig.

[0030] Figure 3 is a sectional view of the fluid control assembly provided by the utility model.

[0031] In the drawings:

[0032] 100, mounting block; 1001, limiting wall;

[0033] 1, valve seat assembly; 11, oil inlet; 12, adjusting sleeve; 121, limiting part; 122, body; 123, plug; 13, valve sleeve; 14, valve seat; 15, valve port; 16, oil return port;

[0034] 2, valve body; 21, oil outlet;

[0035] 3, valve core mechanism; 31, spool valve core; 311, first damping hole; 32, secondary pressure building chamber; 33, taper valve core; 331, second damping hole; 34, elastic assembly; 341, elastic member; 342, support seat;

[0036] 4, buffer piston;

[0037] 51, first channel; 52, second channel; 53, third channel; 54, fourth channel; 55, fifth channel. DETAILED DESCRIPTION

[0038] The utility model will be described in further detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the utility model, and not to limit the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.

[0039] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0040] In the utility model, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0041] In the description of the embodiment, the terms "upper", "lower", "right", etc. orientation or position relationship is based on the orientation or position relationship shown in the drawings, only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0042] The hydraulic motor on the excavator of the engineering machinery will cause the pressure fluctuation due to the instantaneous change of the system hydraulic pressure during the starting and stopping process because of the inertia, thereby bringing greater impact to the hydraulic system, affecting the operation performance of the excavator, and causing greater working burden to the hydraulic elements in the hydraulic system. Therefore, the buffer overflow valve is usually installed in the hydraulic system to absorb the pressure pulse in the buffer system. However, the secondary pressure building time of the buffer overflow valve in the prior art is short, the buffer effect is not obvious, and the hydraulic motor will still have a greater impact when starting and braking.

[0043] To solve the above problems, as shown in Figure 1 、 Figure 2 The embodiment provides a two-stage buffer overflow valve, which comprises a valve seat assembly 1, a valve body 2, a valve core mechanism 3, an oil passage and a buffer piston 4. The valve seat assembly 1 has an oil inlet 11. The valve body 2 is sleeved at one end of the valve seat assembly 1 away from the oil inlet 11. The valve body 2 has an oil outlet 21. The valve core mechanism 3 comprises a sliding valve core 31 which is slidably matched in the valve seat assembly 1. The sliding valve core 31 has a secondary pressure building cavity 32 at one end away from the oil inlet 11. The secondary pressure building cavity 32 is communicated with the oil inlet 11. At least part of the oil passage is arranged in the sliding valve core 31 and / or the valve seat assembly 1 and / or the valve body 2, and the oil passage is communicated with the secondary pressure building cavity 32 and the oil outlet 21. The buffer piston 4 is slidably sleeved in the valve seat assembly 1, and the buffer piston 4 can block or open the oil outlet 21.

[0044] The hydraulic oil enters the secondary pressure building cavity 32 from the oil inlet 11. The hydraulic oil pushes the sliding valve core 31 to move to the right, so that the pre-tightening force of the valve core mechanism 3 is increased, and then the secondary pressure is established. Since the secondary pressure building cavity 32 is communicated with the oil outlet 21 through the oil passage, the hydraulic oil in the secondary pressure building cavity 32 will flow to the oil outlet 21 along the oil passage, and then flow out from the oil outlet 21 to push the buffer piston 4 to slide to the right along the axial direction, so that the pressure in the secondary pressure building cavity 32 slowly rises, the time for completing the establishment of the secondary pressure is prolonged, the buffer effect is improved, the impact of the hydraulic motor when starting and braking is reduced, the operation performance of the excavator is improved, the hydraulic elements in the hydraulic system are protected, and the driver obtains a good driving feeling.

[0045] Specifically, as shown in Figure 1 、 Figure 2As shown, the oil passing channel includes the first channel 51, the second channel 52, the third channel 53, the fourth channel 54 and the fifth channel 55 in sequence. At least part of the first channel 51 is arranged on the spool 31, and the first channel 51 is in communication with the secondary pressure building chamber 32. The gap between the spool 31 and the valve seat assembly 1 forms the second channel 52 along the radial direction of the valve seat assembly 1. At least part of the third channel 53 is arranged on the valve seat assembly 1. The gap between the valve body 2 and the valve seat assembly 1 forms the fourth channel 54 along the radial direction of the valve seat assembly 1. At least part of the fifth channel 55 is arranged on the valve body 2, and the fifth channel 55 is in communication with the oil outlet 21. Thus, the hydraulic oil in the secondary pressure building chamber 32 passes through the first channel 51, the second channel 52, the third channel 53, the fourth channel 54 and the fifth channel 55 in sequence, and reaches the oil outlet 21 through the fifth channel 55, and then flows out from the oil outlet 21 to push the buffer piston 4 to slide.

[0046] Specifically, as shown in Figure 1 , Figure 2 the valve seat assembly 1 includes the adjusting sleeve 12 and the valve sleeve 13. One end of the adjusting sleeve 12 is connected with the valve sleeve 13. The wall of the second channel 52 includes the wall of the adjusting sleeve 12 and the wall of the spool 31. The limit position of the spool 31 includes the first position and the second position. In the first position to the second position, the first channel 51 is in communication with the second channel 52, and the second channel 52 is in communication with the third channel 53. By arranging the valve seat assembly 1 in a split type, the production process and the assembly process can be simplified, and the production cost of the two-stage buffer overflow valve can be reduced. The first position is the position of the spool 31 in the initial state, and the second position is the position of the spool 31 when the secondary pressure building is completed. During the movement of the spool 31, that is, during the establishment of the secondary pressure, the oil passing channel is always in communication with the secondary pressure building chamber 32 and the oil outlet 21, so that the hydraulic oil can flow out from the oil outlet 21 to push the buffer piston 4 during the secondary pressure building.

[0047] In the embodiment, the adjusting sleeve 12 has an abutting surface, and the spool 31 can abut against the abutting surface. At this time, the spool 31 is in the first position. The adjusting sleeve 12 also has a limiting portion 121. When the spool 31 moves to the right to abut against the limiting portion 121, the spool 31 is in the second position, and the secondary pressure building is completed. Specifically, the abutting surface and the limiting portion 121 are distributed along the axial direction.

[0048] Specifically, the adjusting sleeve 12 is slidable along the axial direction. By changing the relative position of the adjusting sleeve 12 and the valve sleeve 13 through the adjusting sleeve 12 sliding along the axial direction, the pre-tightening force of the valve core mechanism 3 can be changed, so as to change the primary pressure of the two-stage buffer overflow valve, and thus the versatility and flexibility of the two-stage buffer overflow valve can be improved.

[0049] In the embodiment, as shown in Figure 1 , Figure 2As shown, the adjusting sleeve 12 comprises a body 122 and a plug 123 arranged at the end of the body 122, the plug 123 is threadedly connected to the body 122, and the abutting surface is located at the plug 123. By arranging the adjusting sleeve 12 in a split manner, the production process and assembly procedure can be simplified, and the production cost can be reduced. Specifically, the adjusting sleeve 12 is threadedly connected to the valve body 2, and by screwing the adjusting sleeve 12, the adjusting sleeve 12 can be axially slid to change the relative position of the adjusting sleeve 12 and the valve sleeve 13.

[0050] Specifically, as shown in Figure 1 、 Figure 2 , the valve seat assembly 1 further comprises a valve seat 14, the valve seat 14 is arranged at both ends of the valve sleeve 13 with the adjusting sleeve 12, and the valve seat 14 has the oil inlet 11. By arranging the valve seat assembly 1 in a split manner, the production process and assembly procedure can be simplified, and the production cost of the two-stage buffer overflow valve can be reduced.

[0051] In the embodiment, as shown in Figure 1 、 Figure 2 , at least part of the adjusting sleeve 12 and at least part of the valve seat 14 are sealingly inserted into the valve sleeve 13 to ensure good circumferential sealing of the valve seat assembly 1.

[0052] Specifically, as shown in Figure 1 、 Figure 2 , the gap between the spool 31 and the adjusting sleeve 12 forms the second channel 52, and at least part of the third channel 53 is arranged on the adjusting sleeve 12.

[0053] Specifically, as shown in Figure 1 、 Figure 2 , the valve core mechanism 3 further comprises a cone spool 33, the cone spool 33 is slidingly fitted in the valve seat assembly 1, the valve seat assembly 1 further comprises a valve port 15 and a return oil port 16, the valve port 15 can communicate the oil inlet 11 and the return oil port 16, and the cone spool 33 can close or open the valve port 15. When the pressure in the hydraulic system changes suddenly, hydraulic oil will flow into the impact cone spool 33 from the oil inlet 11, and since the secondary pressure has not been established in the secondary pressure building chamber 32 at this time, the overflow pressure of this two-stage buffer overflow valve is the primary pressure at this time, the hydraulic oil pushes the cone spool 33 to move left to open the valve port 15, the hydraulic oil reaches the return oil port 16 from the valve port 15, and then flows to the oil tank from the return oil port 16 to absorb the instantaneous impact in the hydraulic system. With the hydraulic oil entering the secondary pressure building chamber 32 to establish the secondary pressure, the cone spool 33 moves right to close the valve port 15. When the pressure of the oil inlet 11 rises to be higher than the sum of the primary pressure and the secondary pressure, the two-stage buffer overflow valve normally starts to overflow.

[0054] Specifically, as shown in Figure 1 、 Figure 2As shown, the spool mechanism 3 further comprises an elastic assembly 34, two ends of the elastic assembly 34 being connected or abutting against the conical spool 33 and the sliding spool 31 respectively. The pre-tightening force of the elastic assembly 34 is the primary pressure of the two-stage buffer overflow valve. With the establishment of the secondary pressure, the sliding spool 31 moves to the right to compress the elastic assembly 34 so that the elastic force of the elastic assembly 34 increases, until the sliding spool 31 abuts against the limiting portion 121, at which time the elastic force of the elastic assembly 34 is the secondary pressure. The hydraulic oil at the oil inlet 11 pushes the conical spool 33, which can move to the left to instantaneously open the overflow when the pressure of the hydraulic oil is greater than the primary pressure. After the establishment of the secondary pressure, the conical spool 33 can move to the left to normally start the overflow when the pressure of the hydraulic oil is greater than the sum of the primary pressure and the secondary pressure. The cooperation of the conical spool 33, the sliding spool 31 and the elastic assembly 34 realizes the establishment of the secondary pressure and the overflow function.

[0055] In the embodiment, as shown in Figure 1 , Figure 2 , the elastic assembly 34 comprises an elastic member 341 and a support seat 342, the support seat 342 being arranged at the end of the elastic member 341 and abutting against or connected to the conical spool 33 and / or the sliding spool 31. The support seat 342 can provide stable support for the elastic member 341, ensuring that the elastic member 341 can stably stretch and contract.

[0056] In an optional embodiment, the elastic assembly 34 is arranged between the sliding spool 31 and the conical spool 33.

[0057] In the embodiment, as shown in Figure 1 , Figure 2 , the sliding spool 31 and the conical spool 33 are in sliding cooperation, so that they can guide and support each other when sliding, improving the stability and accuracy of sliding. At this time, the elastic assembly 34 is sleeved on the outer periphery of the sliding spool 31 and / or the conical spool 33.

[0058] Specifically, as shown in Figure 1 , Figure 2 , the sliding spool 31 is provided with a first damping hole 311, the conical spool 33 is provided with a second damping hole 331, the oil inlet 11, the second damping hole 331, the first damping hole 311 and the secondary pressure building chamber 32 are sequentially communicated. The first damping hole 311 and the second damping hole 331 can delay the flow of hydraulic oil to the secondary pressure building chamber 32 and make the hydraulic oil produce pressure loss, further prolonging the time for the establishment of the secondary pressure and improving the buffering effect.

[0059] As shown in Figure 3As shown, the embodiment also provides a fluid control assembly, which comprises the mounting block 100 and the secondary buffer overflow valve as described above, the secondary buffer overflow valve is arranged in the mounting block 100, the mounting block 100 is provided with a limiting wall 1001, the limiting wall 1001 is used for limiting the limit position of the buffer piston 4 moving rightwards along the axial direction. In the process of establishing the secondary pressure, the buffer piston 4 is pushed by the hydraulic oil to move rightwards, when the buffer piston 4 and the spool 31 are all moved rightwards to the limit position, the establishment of the secondary pressure is completed.

[0060] Obviously, the above embodiments of the utility model are only for clear illustration of the utility model, and are not the limitation of the embodiments of the utility model. For ordinary skilled in the art, various obvious changes, re-adjustment and replacement can be carried out without departing from the protection scope of the utility model. Here, all the embodiments need not and cannot be exhausted. Any modification, equivalent replacement and improvement within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. A two-stage cushion overflow valve characterized by, The valve seat assembly (1) has an oil inlet (11), and the valve body (2) is sleeved on the end of the valve seat assembly (1) away from the oil inlet (11), and the valve body (2) has an oil outlet (21). The spool mechanism (3) includes a sliding spool (31) that is slidingly fitted in the valve seat assembly (1), and the sliding spool (31) has a secondary pressure building cavity (32) at the end away from the oil inlet (11), and the secondary pressure building cavity (32) is in communication with the oil inlet (11). The oil passage is at least partially arranged on the sliding spool (31) and / or the valve seat assembly (1) and / or the valve body (2), and the oil passage is in communication with the secondary pressure building cavity (32) and the oil outlet (21). The buffer piston (4) is slidingly sleeved on the valve seat assembly (1), and the buffer piston (4) can block or open the oil outlet (21). The oil passage includes:

2. The two-stage cushion overflow valve of claim 1, wherein The first passage (51) is at least partially arranged on the sliding spool (31), and the first passage (51) is in communication with the secondary pressure building cavity (32); The second passage (52) is formed by the gap between the sliding spool (31) and the valve seat assembly (1) along the radial direction of the valve seat assembly (1); The third passage (53) is at least partially arranged on the valve seat assembly (1); The fourth passage (54) is formed by the gap between the valve body (2) and the valve seat assembly (1) along the radial direction of the valve seat assembly (1); The fifth passage (55) is at least partially arranged on the valve body (2), the fifth passage (55) is in communication with the oil outlet (21), and the first passage (51), the second passage (52), the third passage (53), the fourth passage (54), and the fifth passage (55) are in communication. The valve seat assembly (1) includes an adjusting sleeve (12) and a valve sleeve (13), one end of the adjusting sleeve (12) is connected with the valve sleeve (13), the wall of the second passage (52) includes the wall of the adjusting sleeve (12) and the wall of the sliding spool (31), the limit position of the sliding spool (31) includes a first position and a second position, and in the first position to the second position, the first passage (51) and the second passage (52) are in communication, and the second passage (52) is in communication with the third passage (53).

3. The two-stage cushion overflow valve of claim 2, wherein, The gap between the sliding spool (31) and the adjusting sleeve (12) forms the second passage (52), and at least part of the third passage (53) is arranged on the adjusting sleeve (12).

4. The two-stage cushion overflow valve of claim 3, wherein, The adjusting sleeve (12) has an abutting surface, the spool mechanism (3) can abut against the abutting surface, and the adjusting sleeve (12) is axially slidable to change the relative position of the valve sleeve (13).

5. The two-stage cushion overflow valve of claim 3, wherein, ​ 6. The two-stage cushion overflow valve of claim 1, wherein, The valve core mechanism (3) further comprises a conical valve core (33) which is slidingly fitted in the valve seat assembly (1), the valve seat assembly (1) further comprises a valve port (15) and an oil return port (16), the valve port (15) can communicate the oil inlet port (11) and the oil return port (16), the conical valve core (33) can close or open the valve port (15).

7. The two-stage cushion overflow valve of claim 6, wherein, The valve core mechanism (3) further comprises an elastic assembly (34), two ends of the elastic assembly (34) are connected or abutted with the conical valve core (33) and the sliding valve core (31) respectively.

8. The two-stage cushion overflow valve of claim 7, wherein, The elastic assembly (34) comprises an elastic piece (341) and a supporting seat (342), the supporting seat (342) is arranged at the end of the elastic piece (341), and the supporting seat (342) abuts or is connected with the conical valve core (33) and / or the sliding valve core (31).

9. The two-stage cushion overflow valve of claim 6, wherein, The sliding valve core (31) is provided with a first damping hole (311), the conical valve core (33) is provided with a second damping hole (331), the oil inlet port (11), the second damping hole (331), the first damping hole (311) and the secondary pressure building cavity (32) are sequentially communicated.

10. A fluid control assembly characterized by, The installation block (100) is provided with a limiting wall (1001) for limiting the limit position of the rightward axial movement of the buffer piston (4).

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