Multi-way valve and engineering machinery

Abstract

The present invention provides a multi-way valve and engineering machinery, which relates to the technical field of multi-way valves, including a valve body, a main valve core and a stopper sleeve; the end cover, the stopper sleeve and the end face of the valve body form a first cavity; the inner side wall of the main valve core and the stopper sleeve forms a second cavity, and a fixed throttle hole and a pressure relief structure are arranged between the first cavity and the second cavity, and the fixed throttle hole and the pressure relief structure are respectively used for the communication between the first cavity and the second cavity, and the pressure relief structure can be opened and closed so that the moving speed of the main valve core can be adjusted. When the main valve core returns to the middle position, the liquid in the second cavity can be connected to the first cavity through the fixed throttle hole and the pressure relief structure, and the main valve core can move quickly. As the main valve core approaches the middle position, the liquid in the second cavity can only flow to the first cavity through the fixed throttle hole, so that the speed of the main valve core is slowed down, avoiding the slow response of the actuator when starting, and reducing the impact when decelerating and stopping.

Description

Technical Field

[0001] The invention relates to the technical field of multi-way valves, in particular to a multi-way valve and engineering machinery. Background Art

[0002] The structure of the existing multi-way valve is as follows Figure 1 As shown, there is a main valve core hole 03 on the valve body 01, and the main valve core 02 is installed in the main valve core hole 03. The two ends of the main valve core hole 03 are equipped with end covers 04. The end cover 04 and the end surface of the valve body 01 form a closed oil chamber 0A, and the closed oil chamber 0A is equipped with a spring 05 and a stopper sleeve 06. When the hydraulic excavator equipped with this structure of the main valve is operated, the pilot pressure oil enters the closed oil chamber 0A formed by the end cover 04 and the valve body 01, so that the main valve core 02 moves to the other end, and the pressure oil at the other end returns to the oil tank. In this process, once the main valve core 02 returns to the middle position, at a large excavation speed, excavation force and travel speed, the excavator's working device, rotary device and travel device suddenly start and stop due to the inertia of the operation, which will affect the operating efficiency and safety of the excavator operator, and will also cause certain damage to the valve core inside the main valve, so this impact should be avoided.

[0003] In order to reduce the large impact force generated when the main valve core 02 returns to the middle position, a check valve core 11 with a throttling hole is added inside the stop sleeve 04. When operating the pilot valve, the pilot pressure oil enters the end cover and reaches the check valve core 11 inside the stop sleeve. Inside the check valve core 11 with a throttling hole, there is an end cover channel 010 in the closed cavity formed by the end cover 04 and the valve body 01. Therefore, after the pilot pressure oil enters, it can flow to the inside of the closed oil chamber 0A cavity without resistance, and then act on the end face of the main valve core 02 and the stop sleeve 06. The right end face of the main valve core 02 contacts the stop platform inside the right stop sleeve 06, compressing the spring 05 on the right side. Since the pilot pressure is greater than the spring force, the main valve core 02 in the closed oil chamber 0A at the other end will have a displacement st. When the spring force and the pilot pressure are balanced, the displacement of the main valve core 02 stops.

[0004] After that, when the pilot valve returns to the middle position, the oil pressure at this end of the pressure oil will decrease, and the end face of the main valve core 02 at the other end will be displaced in the opposite direction for a distance due to the action of the spring force, and then return to the middle position. At this time, when the oil flows out from the check valve core 11, because it blocks the channel for the oil to flow to the outside, when the oil enters the closed oil chamber 0A, it can only be discharged through the throttle hole in the middle of the check valve core 11. The throttle hole is used for flow regulation to control the speed of the actuator, so the result is that the speed of the main valve core 02 returning to the middle position is slowed down, and the speed of the oil returning to the oil tank through the throttle hole is also slowed down, thereby reducing the impact when the actuator stops.

[0005] The technical problems are as follows:

[0006] In the above structure, when the working mechanism stops and the main valve core 02 returns to the middle position, all the pressure oil in the return stroke is discharged back to the oil tank only through the throttle hole on the check valve core 11, that is, the return characteristics of the main valve core 02 are all determined by the characteristics of this throttle hole, but the characteristics of this throttle hole are easily affected by temperature changes, because the viscosity of hydraulic oil is very sensitive to changes in temperature. When the temperature rises, the cohesive force between the oil molecules decreases, and the viscosity decreases accordingly, and vice versa. The viscosity increases. Therefore, this structure is greatly affected by changes in the operating environment temperature and seasons; as a result, when the actuator stops, the impact degree of the main valve core 02 during the return stroke will fluctuate, that is, the actuator stop time will become very long in cold areas, and the impact reduction effect will be ineffective in high temperature environments. In addition, when this check valve core 11 is added between the two ends of the end cover of the main valve core 02, when the actuator starts, the oil to be discharged from the closed oil chamber 0A is only discharged through the throttle hole of the check valve core 11, so there will be problems such as slow start response and the actuator cannot start smoothly. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-way valve and engineering machinery to alleviate the technical problems that the throttle hole of the check valve core of the existing multi-way valve is greatly affected by temperature, and the starting response is slow and the actuator cannot start smoothly.

[0008] The multi-way valve provided by the present invention comprises a valve body, a main valve core and a stopper sleeve; end covers are arranged at both ends of the valve body, the main valve core is arranged in the main valve core hole on the valve body, the stopper sleeve is sleeved on the end of the main valve core, the end cover, the stopper sleeve and the end surface of the valve body form a first cavity, the main valve core and the inner side wall of the stopper sleeve form a second cavity, a fixed throttle hole and a pressure relief structure are arranged between the first cavity and the second cavity, and the fixed throttle hole and the pressure relief structure are respectively used for the communication between the first cavity and the second cavity;

[0009] The pressure relief structure can be opened and closed.

[0010] Furthermore, a piston hole is provided at one end of the stop sleeve away from the main valve core, a piston is provided in the piston hole, the inner cavity of the stop sleeve, the piston and the main valve core constitute the second cavity, and the fixed throttling hole is provided on the piston.

[0011] Furthermore, a first restoring member is disposed in the first cavity, one end of the first restoring member is connected to the end cover, and the other end of the first restoring member is connected to the stop sleeve.

[0012] Furthermore, a second return member is disposed in the second cavity, one end of the second return member is connected to the piston, and the other end of the second return member is connected to the stop sleeve;

[0013] The pressure relief structure comprises a first groove, a second groove and a connecting channel;

[0014] The first groove is arranged on the inner side wall of the stopper sleeve, the second groove and the connecting channel are arranged on the piston at intervals, the second groove is communicated with the first cavity and is closer to the end cover than the connecting channel; the connecting channel communicates the second cavity with the first groove;

[0015] The second groove and the first groove can be connected and disconnected during the sliding process of the piston and the stopper sleeve.

[0016] Furthermore, the first groove is an annular groove, which is arranged on the circumference of the inner side wall of the retaining sleeve.

[0017] Furthermore, the number of the second grooves is plural and they are arranged at intervals in the circumferential direction of the outer side wall of the piston.

[0018] Furthermore, there are multiple connecting channels, which are arranged at intervals along the circumference of the piston.

[0019] Furthermore, the cross-sectional area of ​​the piston is smaller than the cross-sectional area of ​​the main valve core.

[0020] Furthermore, the cross-sectional area of ​​the piston is 0.55-0.85 times the cross-sectional area of ​​the main valve core.

[0021] The engineering machinery provided by the present invention comprises the multi-way valve.

[0022] The multi-way valve provided by the present invention comprises a valve body, a main valve core and a stop sleeve; end covers are arranged at both ends of the valve body, the main valve core is arranged in the main valve core hole on the valve body, the stop sleeve is sleeved on the end of the main valve core, the end cover, the stop sleeve and the end surface of the valve body form a first cavity, the main valve core and the inner side wall of the stop sleeve form a second cavity, a fixed throttling hole and a pressure relief structure are arranged between the first cavity and the second cavity, the fixed throttling hole and the pressure relief structure are respectively used for the connection between the first cavity and the second cavity; the pressure relief structure can be opened and closed.

[0023] When the main valve core returns to the neutral position, the pressure relief structure opens, and the liquid in the second cavity can be connected to the first cavity through the fixed throttle hole and the pressure relief structure, and the main valve core can move quickly toward the neutral position. As the main valve core approaches the neutral position, the pressure relief structure closes. At this time, the liquid in the second cavity can only flow to the first cavity through the fixed throttle hole, thereby slowing down the speed at which the main valve core returns to the neutral position. In the process of the main valve core returning to the neutral position, the main valve core can move quickly in the front stroke and slowly in the rear stroke, which can avoid the slow response of the actuator when it is started and reduce the impact of the actuator when it decelerates and stops.

[0024] The engineering machinery provided by the present invention comprises the multi-way valve, so the engineering machinery also has the advantages of the multi-way valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a structural schematic diagram of a multi-way valve in the prior art;

[0027] Figure 2 A schematic diagram of the structure of a multi-way valve provided in an embodiment of the present invention;

[0028] Figure 3 for Figure 2 A magnified view of part W in FIG.

[0029] Figure 4 A schematic diagram of the opening of the pressure relief structure of the multi-way valve provided in an embodiment of the present invention;

[0030] Figure 5 A cross-sectional view of a piston of a multi-way valve provided in an embodiment of the present invention;

[0031] Figure 6 A structural diagram of a second groove of a multi-way valve provided in an embodiment of the present invention;

[0032] Figure 7 A simplified structural diagram of a multi-way valve provided in an embodiment of the present invention;

[0033] Figure 8 A multi-way valve provided in an embodiment of the present invention.

[0034] Icon: 01-valve body; 02-main valve core; 03-main valve core hole; 04-end cover; 05-spring; 06-stop sleeve; 010-end cover channel; 11-check valve core; 0A-enclosed oil chamber;

[0035] 1-valve body; 2-main valve core; 3-main valve core hole; 4-end cover; 5-first reset member; 6-stop sleeve; 9-stop platform; 10-end cover channel; 14-fixed throttle hole; 91-end face of main valve core; 99-piston hole; 101-piston; 102-second reset member; 103-connecting channel; 105-second groove; 106-first groove; 107-variable opening channel;

[0036] A-first cavity; B-second cavity. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figures 2 to 8 As shown, the multi-way valve provided in this embodiment includes a valve body 1, a main valve core 2 and a stop sleeve 6; end covers 4 are arranged at both ends of the valve body 1, the main valve core 2 is arranged in the main valve core hole 3 on the valve body 1, and the stop sleeve 6 is sleeved on the end of the main valve core 2, the end cover 4, the stop sleeve 6 and the end surface of the valve body 1 form a first cavity A, and the inner side walls of the main valve core 2 and the stop sleeve 6 form a second cavity B, and a fixed throttling hole 14 and a pressure relief structure are arranged between the first cavity A and the second cavity B, and the fixed throttling hole 14 and the pressure relief structure are respectively used for connecting the first cavity A and the second cavity B, and the pressure relief structure can be opened and closed so that the moving speed of the main valve core 2 can be adjusted.

[0039] When the main valve core 2 returns to the center position, the pressure relief structure opens, and the liquid in the second chamber B can be connected to the first chamber A through the fixed throttle hole 14 and the pressure relief structure, and the main valve core 2 can move quickly toward the center position. As the main valve core 2 approaches the center position, the pressure relief structure closes. At this time, the liquid in the second chamber B can only flow to the first chamber A through the fixed throttle hole 14, thereby slowing down the speed at which the main valve core 2 returns to the center position. In the process of the main valve core 2 returning to the center position, the main valve core 2 can move quickly in the front part of the stroke and slowly in the rear part of the stroke, which can avoid the slow response of the actuator when it is started and reduce the impact of the actuator when it decelerates and stops.

[0040] In this embodiment, since the end cover 4 and the main valve core 2 are arranged on the left and right, the present invention only takes the left side as an example for description, and the working structure and principle of the right side are similar to those of the left side.

[0041] Furthermore, a piston hole 99 is provided at one end of the stopper sleeve 6 away from the main valve core 2 , a piston 101 is provided in the piston hole 99 , the inner cavity of the stopper sleeve 6 , the piston 101 and the main valve core 2 constitute a second cavity B, and a fixed throttling hole 14 is provided on the piston 101 .

[0042] Furthermore, a first restoring member 5 is disposed in the first cavity A, one end of the first restoring member 5 is connected to the end cover 4 , and the other end of the first restoring member 5 is connected to the stopper sleeve 6 .

[0043] The present invention is similar to the prior art in that the first cavity A is provided at both ends of the main valve core 2. The extended portion of the main valve core 2 cooperates with the stopper sleeve 6, and its end can be supported by the stopper 9 inside the stopper sleeve 6, one end of the first reset member 5 is closely attached to the convex shoulder of the outer wall of the stopper sleeve 6, and the other end of the first reset member 5 is in contact with the end of the end cover 4.

[0044] A second restoring member 102 is disposed in the second cavity B. One end of the second restoring member 102 is connected to the piston 101 , and the other end of the second restoring member 102 is connected to the stopper sleeve 6 .

[0045] In the present invention, a piston hole 99 is provided on the other side of the matching part of the stopper sleeve 6 and the main valve core 2, and a piston 101 is assembled in the piston hole 99 so that the piston 101 is slidably connected in the piston hole 99. Through the structural matching between the piston 101, the stopper sleeve 6 and the main valve core 2, a second cavity B is formed in the first cavity A.

[0046] One end of the piston 101 is connected to the second cavity B, and the other end of the piston 101 is connected to the inner side of the end cover 4 .

[0047] In this embodiment, a second reset member 102 is arranged in the second cavity B, one end of the second reset member 102 is connected to the piston 101, and the other end of the second reset member 102 is connected to the inner wall of the stop sleeve 6. When the end of the piston 101 away from the main valve core 2 abuts against the inner wall of the end cover 4 and the main valve core 2 is about to return to the middle position, the second reset member 102 in the second cavity B can push the stop sleeve 6 to move to the right, thereby realizing the disconnection of the first groove 106 and the second groove 105.

[0048] Preferably, the first restoring member and the second restoring member 102 are both springs.

[0049] It should be noted that the first restoring member 5 and the second restoring member 102 may also be spring sheets.

[0050] A pressure relief structure is also provided between the second cavity B and the first cavity A. When the main valve core 2 returns to the middle position, the pressure relief structure is opened first, so that the first cavity A and the second cavity B can be connected through both the pressure relief structure and the fixed throttle hole 14, so that the liquid in the second cavity can quickly flow to the first cavity A and return to the oil tank through the oil circuit, so that the main valve core 2 can move quickly. When the main valve core 2 is about to reach the middle position, the pressure relief structure is closed. At this time, the liquid in the second cavity B can only be discharged to the first cavity A through the fixed throttle hole 14, so as to slow down the speed of the main valve core 2 returning to the middle position.

[0051] It should be noted that the liquid in the first cavity A and the second cavity B is hydraulic oil.

[0052] The pressure relief structure includes a first groove 106 , a second groove 105 and a connecting channel 103 .

[0053] The first groove 106 is arranged on the inner wall of the stopper sleeve 6, the second groove 105 and the connecting channel 103 are arranged on the piston 101 at intervals, the second groove 105 is connected to the first cavity A and is closer to the end cover 4 than the connecting channel 103; the connecting channel 103 connects the second cavity B with the first groove 106.

[0054] The second groove 105 and the first groove 106 can be connected and disconnected during the sliding process of the piston 101 and the stopper sleeve 6 .

[0055] Specifically, a first groove 106 is provided on the inner wall of the stopper sleeve 6, and the first groove 106 is connected to the second cavity B through the connecting channel 103 on the piston 101. The piston 101 is also provided with a second groove 105, which extends along the length direction of the piston 101 and is connected to the first cavity A. When the stopper sleeve 6 moves to the left relative to the piston 101, the first groove 106 can be connected to the second groove 105, and the liquid in the second cavity B can pass through the connecting channel 103, the first groove 105 in sequence. 6 and the second groove 105 are discharged to the first cavity A, thereby realizing resistance-free communication between the second cavity B and the first cavity A. At the same time, the liquid in the second cavity B can also be discharged to the first cavity A through the fixed throttling hole 14, and the speed at which the main valve core 2 returns to the middle position becomes faster. When the main valve core 2 moves quickly to the middle position, the stop sleeve 6 moves to the right relative to the piston 101, and the first groove 106 is disconnected from the second groove 105. The liquid in the second cavity B can only be discharged to the first cavity A through the fixed throttling hole 14, and the speed at which the main valve core 2 returns to the middle position becomes slower.

[0056] Preferably, the first groove 106 is an annular groove, which is arranged on the circumference of the inner side wall of the stopper sleeve 6 .

[0057] Specifically, when the stopper sleeve 6 is located Figure 3 When it is in the position, it is blocked by the part of length t shown in the figure, but as the baffle sleeve 6 moves to the left side in the figure, the second cavity B and the first cavity A are connected in addition to the fixed throttle hole 14, and the second groove 105 and the first groove 106 are connected through the variable opening channel 107.

[0058] Furthermore, there are multiple second grooves 105 , which are arranged at intervals in the circumferential direction of the outer side wall of the piston 101 .

[0059] In this embodiment, the number of the second grooves 105 is two. Figure 5 As can be seen in the figure, a second groove 105 is provided at the upper end of the piston 101, and a second groove 105 is also provided at the opposite lower end of the piston 101. Figure 6 FIG. 1 is a structural diagram of the second groove 105 .

[0060] Furthermore, there are multiple connecting channels 103 , which are arranged at intervals along the circumference of the piston 101 .

[0061] In this embodiment, the number of connecting channels 103 is four, and they are arranged at intervals along the circumference of the piston 101. Figure 5 As shown, the angle between two adjacent connecting channels 103 is 90 degrees. The advantage of multiple connecting through holes is that when some of the connecting through holes are blocked, the second cavity B can still communicate with the first groove 106 through other connecting channels.

[0062] Furthermore, the cross-sectional area m of the piston 101 is smaller than the cross-sectional area M of the main valve core 2 .

[0063] Preferably, the cross-sectional area m of the piston 101 is 0.55-0.85 times the cross-sectional area M of the main valve core 2 .

[0064] Furthermore, a stopper 9 is provided on the inner wall of the stopper sleeve 6 , and the stopper 9 is used to abut against the end surface 91 of the main valve core, so that the main valve core 2 can drive the stopper sleeve 6 to move.

[0065] The multi-way valve provided in this embodiment has Figure 7 , Figure 8 When the pilot pressure oil flows to the first cavity A through the end cover channel 10, Figure 7 As shown in the figure, the main valve core 2 moves with the stopper sleeve 6, compressing the spring in the first cavity A on the right, and stops after the displacement st. After that, when the main valve core 2 returns to the middle position, the pressure in the end cover channel 10 decreases, and the spring in the first cavity A on the right applies a force Fs to the main valve core 2 to return to the left in the figure through the stopper sleeve 6. Through this force, the end face 91 of the main valve core moves in the second cavity B, generating a pressure in the same direction as the elastic force of the above-mentioned spring. Through this pressure, part of the pressure oil in the second cavity B passes through the Figure 7 The fixed throttle hole 14 shown in the figure is arranged toward the first cavity A and flows out from the end cover channel 10. Figure 8 As shown, on the opposite side of the stopper sleeve 6, when the action cross sections of the main valve core 2 and the piston 101 are set to M and m respectively, the cross-sectional area M of the main valve core 2 is larger than the cross-sectional area m of the piston 101, so the hydraulic pressure formed acts together with the elastic force of the spring on the right side. At this time, the force of the spring is smaller than the combined force of the spring on the right side compressed during the movement of the main valve core 2 and the hydraulic pressure, so the pressure of the second cavity B causes the stopper sleeve 6 to move to the left in the figure. Figure 4 As shown, the variable opening passage 107 is opened. Finally, in this process, since the pressure oil in the second cavity B is discharged from the fixed throttle hole 14 and the variable opening passage 107 to the first cavity A, the speed at which the main valve core 2 returns to the middle position becomes faster.

[0066] Afterwards, when the main valve core 2 moves toward the neutral position, the force exerted by the spring in the first chamber A on the right side on the main valve core 2 gradually decreases, the pressure in the second chamber B also gradually decreases, and under the joint action of the second reset member 102 (i.e., the spring in the second chamber B), the stopper sleeve 6 returns to the neutral position. Figure 3 The position shown, so Figure 4 The variable opening passage 107 is blocked, and the pressure oil in the second chamber B is discharged only from the fixed throttle hole 14. Therefore, the speed at which the main valve core 2 returns to the neutral position is slowed down.

[0067] Finally, when the main valve core 2 returns to the middle position, in the above-mentioned first half of the stroke, the main valve core 2 returns to the middle position without delay, and in the second half of the stroke, the pressure oil in the second chamber B is only discharged from the fixed throttle hole 14, therefore, the impact of the actuator when it decelerates and stops can be appropriately reduced.

[0068] In general, after the main valve core 2 returns to the middle position, Figure 7 In the case where the pilot pressure oil flows into the end cover channel 10 on the right side, Figure 2 As shown in FIG. 1 , the main valve core 2 moves leftward together with the left stopper sleeve 6 in the figure. In this case, the pressure oil in the second chamber B is discharged to the first chamber A through the fixed throttle hole 14 of the piston 101. In addition, when the main valve core 2 moves with the stopper sleeve 6 as shown in FIG. Figure 3 After the length of t shown, due to Figure 4 The variable opening passage 107 is shown to be open, and the pressure oil in the second chamber B is discharged through the fixed throttle hole 14 and the variable opening passage 107. The main valve core 2 moves quickly in a short time, so that the actuator can be prevented from responding slowly when starting.

[0069] Furthermore, by appropriately setting the diameter of the piston 101 relative to the main valve element 2, the characteristics during startup and deceleration and stopping can be optimized.

[0070] The engineering machinery provided in this embodiment includes the multi-way valve, so the engineering machinery also has the advantages of the multi-way valve.

[0071] To summarize, the multi-way valve provided by the present invention comprises a valve body 1, a main valve core 2 and a stop sleeve 6; end covers 4 are arranged at both ends of the valve body 1, the main valve core 2 is arranged in the main valve core hole 3 on the valve body 1, the stop sleeve 6 is sleeved on the end of the main valve core 2, the end cover 4, the stop sleeve 6 and the end face of the valve body 1 form a first cavity A, the inner side walls of the main valve core 2 and the stop sleeve 6 form a second cavity B, a fixed throttling hole 14 and a pressure relief structure are arranged between the first cavity A and the second cavity B, the fixed throttling hole 14 and the pressure relief structure are respectively used for connecting the first cavity A and the second cavity B; the pressure relief structure can be opened and closed so that the moving speed of the main valve core 2 can be adjusted. When the main valve core 2 returns to the center position, the pressure relief structure opens, and the liquid in the second chamber B can be connected to the first chamber A through the fixed throttle hole 14 and the pressure relief structure, and the main valve core 2 can move quickly toward the center position. As the main valve core 2 approaches the center position, the pressure relief structure closes. At this time, the liquid in the second chamber B can only flow to the first chamber A through the fixed throttle hole 14, thereby slowing down the speed at which the main valve core 2 returns to the center position. In the process of the main valve core 2 returning to the center position, the main valve core 2 can move quickly in the front part of the stroke and slowly in the rear part of the stroke, which can avoid the slow response of the actuator when it is started and reduce the impact of the actuator when it decelerates and stops.

[0072] The engineering machinery provided by the present invention comprises the multi-way valve mentioned above, and therefore, the engineering machinery also has the advantages of the multi-way valve mentioned above.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-way valve, comprising a valve body (1), a main valve core (2) and a stopper sleeve (6); end covers (4) are arranged at both ends of the valve body (1); the main valve core (2) is arranged in a main valve core hole (3) on the valve body (1); the stopper sleeve (6) is sleeved on the end of the main valve core (2); the end cover (4), the stopper sleeve (6) and the end surface of the valve body (1) form a first cavity (A), characterized in that: The inner side walls of the main valve core (2) and the stopper sleeve (6) form a second cavity (B), and a fixed throttle hole (14) and a pressure relief structure are provided between the first cavity and the second cavity, and the fixed throttle hole (14) and the pressure relief structure are respectively used for the communication between the first cavity (A) and the second cavity (B); The pressure relief structure can be opened and closed; The end of the stopper sleeve (6) away from the main valve core (2) is provided with a piston hole (99), a piston (101) is provided in the piston hole (99), the inner cavity of the stopper sleeve (6), the piston (101) and the main valve core constitute the second cavity (B), and the fixed throttle hole (14) is provided on the piston (101); A first restoring member (5) is arranged in the first cavity (A), one end of the first restoring member (5) is connected to the end cover (4), and the other end of the first restoring member (5) is connected to the stop sleeve (6); A second restoring member (102) is disposed in the second cavity (B), one end of the second restoring member (102) is connected to the piston (101), and the other end of the second restoring member (102) is connected to the stopper sleeve (6); The pressure relief structure comprises a first groove (106), a second groove (105), a connecting channel (103) and a variable opening channel (107); the first groove (106) is arranged on the inner side wall of the stopper sleeve (6); the second groove (105) and the connecting channel (103) are arranged on the piston (101) at intervals; the second groove (105) is communicated with the first cavity (A) and is closer to the end cover (4) than the connecting channel (103); the connecting channel (103) communicates with the second cavity (B) and the first groove (106); The second groove (105) and the first groove (106) can be connected and disconnected during the sliding process of the piston (101) and the stopper sleeve (6); when connected, the second groove (105) and the first groove (106) are connected through the variable opening channel (107).

2. The multi-way valve according to claim 1, characterized in that: The first groove (106) is an annular groove, which is arranged on the circumference of the inner side wall of the stopper sleeve (6).

3. The multi-way valve according to claim 1, characterized in that: The number of the second grooves (105) is plural and they are arranged at intervals in the circumferential direction of the outer side wall of the piston (101).

4. The multi-way valve according to claim 1, characterized in that: The connecting channels (103) are multiple in number and are arranged at intervals along the circumference of the piston (101).

5. The multi-way valve according to claim 1, characterized in that: The cross-sectional area of ​​the piston (101) is smaller than the cross-sectional area of ​​the main valve core (2).

6. The multi-way valve according to claim 5, characterized in that: The cross-sectional area of ​​the piston (101) is 0.55-0.85 times the cross-sectional area of ​​the main valve core (2).

7. An engineering machine, characterized in that: A multi-way valve comprising the multi-way valve according to any one of claims 1 to 6.

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