Manual valve and forklift

Abstract

The manual valve comprises a main valve body, a valve rod and a compensation valve, the main valve body is provided with a valve cavity, a working channel and a first oil return channel, and the valve rod is movably arranged in the valve cavity; the compensation valve comprises a first valve body, a first elastic piece and a first valve element, and the first elastic piece exerts a preset pulling force effect on the first valve element in the direction close to the first valve body. When the manual valve is in a descending working condition, oil liquid entering the first oil return channel through the valve rod in the working channel can exert a first pressure effect on the end, away from the first valve body, of the first valve element; oil in the working channel can enter the first inner cavity and exert a second pressure effect on the end, close to the first elastic piece, of the first valve element; the first pressure effect, the second pressure effect and the preset tension effect can enable the first valve element to reach a stress balance state. According to the manual valve and the forklift, the problem that the controllability of the forklift is poor is solved.

Description

Technical Field

[0001] The present application relates to the technical field of forklifts, and in particular to a manual valve and a forklift. Background Art

[0002] In traditional forklift manual valves, the oil returns directly to the T port after passing through the valve stem throttle groove. The disadvantage is that when the cylinder is subjected to different loads, the oil pressure passing through the valve stem throttle groove is also different. Since the flow rate is proportional to the area and the pressure difference, the same throttle groove area and different loads will result in different flow rates. That is, for the same valve stem opening, when the forklift load is different, the forklift arm's descending speed will also be different. This results in poor controllability of the forklift. Utility Model Content

[0003] Based on this, it is necessary to provide a manual valve and a forklift to solve the problem that when the load of the existing forklift is different, the lowering speed of the forklift arm is also different, which leads to poor controllability of the forklift.

[0004] The manual valve provided in the present application includes a main valve body, a valve stem and a compensation valve. The main valve body is provided with a valve cavity, a working channel and a first oil return channel, and the valve stem is movably arranged in the valve cavity; the compensation valve includes a first valve body, a first elastic member and a first valve core, the first valve core extends out of one end of the first valve body, one end of the first elastic member is connected to the first valve body, and the other end is connected to the first valve core, so as to apply a preset pulling force on the first valve core toward the direction close to the first valve body; the end of the first valve core away from the first valve body can open or close the first oil return channel. When the manual valve is in a descending working condition, the working channel can be connected to the first oil return channel through the valve stem, and the oil entering the first oil return channel can apply a first pressure action on the end of the first valve core away from the first valve body; the first valve body is provided with a first inner cavity connected to the working channel, so that the oil in the working channel can enter the first inner cavity and apply a second pressure action on the end of the first valve core close to the first elastic member; the first pressure action, the second pressure action and the preset pulling force can make the first valve core reach a force balance state.

[0005] In one embodiment, the manual valve further includes a differential one-way valve and a solenoid valve. The movable end of the differential one-way valve is movably arranged in the working channel, and the solenoid valve can control the differential one-way valve to open or close the working channel.

[0006] In one embodiment, the main valve body is provided with a second oil return channel and a control channel, and the movable end of the solenoid valve is provided in the control channel to open or close the control channel; the differential one-way valve includes a second valve core and a second elastic member, the second elastic member has a tendency to push the second valve core to close the working channel, and the second valve core is provided with a second inner cavity connecting the working channel and the control channel; when the manual valve is in a descending condition and the solenoid valve opens the control channel, the oil in the working channel can pass through the second inner cavity, the control channel and the valve stem in sequence to connect to the second oil return channel, and the oil in the working channel can push the second valve core to overcome the elastic force of the second elastic member and move to open the working channel; when the solenoid valve closes the control channel, the oil in the working channel can enter the second inner cavity and increase the hydraulic pressure of the second inner cavity, and the oil in the second inner cavity can cooperate with the second elastic member to push the second valve core to close the working channel.

[0007] In one embodiment, the manual valve further includes a normally closed contact switch, which is electrically connected to the solenoid valve. When the driver leaves the seat, the normally closed contact switch is in an off-state to keep the solenoid valve closed. When the driver sits on the seat, the normally closed contact switch is in an on-state to keep the solenoid valve in a ready-to-open state.

[0008] In one embodiment, the end of the valve stem away from the compensating valve extends out of the main valve body, and the outer peripheral side of the end of the valve stem extending out of the main valve body is provided with an annular groove arranged around its own axial direction, and the annular groove is provided with a first inclined surface close to the main valve body, a second inclined surface away from the main valve body, and a bottom surface connecting the first inclined surface and the second inclined surface; when the valve stem is in the middle position, the normally closed contact switch is located between the first inclined surface and the second inclined surface and does not contact the annular groove, and the normally closed contact switch is in a power-off state; when the manual valve is in a descending condition, the first inclined surface can guide the normally closed contact switch.

[0009] In one embodiment, a communication groove extending along the axial direction of the first valve core is provided on the outer peripheral side of the first valve core, and the working channel is connected to the first inner cavity through the communication groove.

[0010] In one embodiment, the compensation valve also includes a connecting rod, one end of which is fixedly connected to the first valve core, and the other end extends toward the first inner cavity. The first elastic member is a compression spring, and the first elastic member is sleeved on the outer peripheral side of the connecting rod. One end of the first elastic member abuts against the connecting rod, and the other end abuts against the first valve body.

[0011] In one embodiment, the first elastic member is a tension spring, and one end of the first elastic member is fixedly connected to the inner wall of the first inner cavity, and the other end is fixedly connected to the first valve core.

[0012] In one embodiment, the main valve body is further provided with a feedback channel, and the valve stem is provided with a process hole. When the manual valve is in an ascending condition, the working channel can be connected to the feedback channel through the process hole, so that the feedback channel can feedback the oil pressure of the working channel.

[0013] The present application also provides a forklift, which includes the manual valve described in any one of the above embodiments.

[0014] Compared to the prior art, the manual valve and forklift provided by this application utilize a working channel to supply both sides of the first valve core. However, due to the loss of hydraulic pressure caused by the oil entering through the valve stem, the pressure of the oil directly entering the first inner chamber from the working channel is slightly greater than the pressure of the oil entering the first oil return channel from the working channel through the valve stem. Furthermore, actual measurements show that the difference between the first and second pressures remains constant regardless of the pressure of the oil in the working channel.

[0015] Therefore, by providing the first elastic member to compensate for pressure loss on the right side of the first valve core, the oil pressure on both sides of the first valve core can be dynamically balanced. When the first valve core closes the first oil return channel, the oil pressure in the first oil return channel near the working channel will rise, thereby breaking the pressure balance on both sides of the first valve core. At this time, the oil pushes the first valve core to open the first oil return channel, thereby achieving a new pressure balance and enabling oil backflow.

[0016] Since the pressure difference of the oil at both ends of the first valve core is fixed, the oil flow through the first valve core is only proportional to the throttling area of the oil. In this way, no matter how much the load at the output end of the forklift is, as long as the throttling area of the oil remains unchanged, the return speed of the oil is consistent, that is, the descent speed of the forklift is consistent, thereby greatly improving the controllability of the manual valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A cross-sectional view of a manual valve according to an embodiment of the present application;

[0019] Figure 2 This is a system connection diagram of a manual valve according to an embodiment of the present application.

[0020] Figure markings: 100, main valve body; 110, valve cavity; 120, working channel; 130, first oil return channel; 140, second oil return channel; 150, control channel; 160, feedback channel; 170, oil inlet channel; 200, valve stem; 210, throttling groove; 220, process hole; 230, annular groove; 231, first inclined surface; 232, second inclined surface; 233, bottom surface; 300, compensation valve; 310, first valve body; 311, first inner cavity; 312, second step structure; 320, first elastic member; 330, first valve core; 340, connecting rod; 341, first step structure; 400, differential one-way valve; 410, second valve core; 411, second inner cavity; 420, second elastic member; 500, solenoid valve; 600, bracket; 700, output end. DETAILED DESCRIPTION

[0021] In traditional forklift manual valves, the oil returns directly to the T port after passing through the valve stem throttle groove. The disadvantage is that when the cylinder is subjected to different loads, the oil pressure passing through the valve stem throttle groove is also different. Since the flow rate is proportional to the area and the pressure difference, the same throttle groove area and different loads will result in different flow rates. That is, for the same valve stem opening, when the forklift load is different, the forklift arm's descending speed will also be different. This results in poor controllability of the forklift.

[0022] In order to solve the problem that when the load of the existing forklift is different, the lowering speed of the forklift arm is also different, which leads to poor controllability of the forklift, the present application provides a manual valve and a forklift.

[0023] See also Figure 1 and Figure 2 The manual valve includes a main valve body 100, a valve stem 200 and a compensation valve 300. The main valve body 100 is provided with a valve cavity 110, an oil inlet channel 170, a working channel 120 and a first oil return channel 130. The oil inlet channel 170 is used to allow the oil pumped in by the oil pump to pass through. The valve stem 200 can be movably arranged in the valve cavity 110.

[0024] The compensation valve 300 includes a first valve body 310, a first elastic member 320 and a first valve core 330. The first valve core 330 extends from one end of the first valve body 310. One end of the first elastic member 320 is connected to the first valve body 310, and the other end is connected to the first valve core 330 to apply a preset pulling force to the first valve core 330 in the direction close to the first valve body 310.

[0025] The first valve core 330 is movably arranged in the first oil return channel 130, and the end of the first valve core 330 away from the first valve body 310 can open or close the first oil return channel 130. When the manual valve is in a descending working condition, that is, when the valve stem 200 moves downward, the working channel 120 is connected to the first oil return channel 130 through the valve stem 200, and the oil entering the first oil return channel 130 can apply a first pressure to the end of the first valve core 330 away from the first valve body 310.

[0026] The first valve body 310 defines a first inner cavity 311 , which is directly connected to the working channel 120 , so that the oil in the working channel 120 can enter the first inner cavity 311 and apply a second pressure to an end of the first valve core 330 close to the first elastic member 320 .

[0027] Among them, the difference between the second pressure and the first pressure is equal to the preset tension, and the first pressure and the preset tension are in the same direction. The resultant force formed by the two is equal to the second pressure in magnitude and opposite in direction. That is, the first pressure, the second pressure and the preset tension can make the first valve core 330 reach a force balance state.

[0028] It should be noted that although the oil on both sides of the first valve core 330 comes from the working channel 120, the oil entering through the valve stem 200 will lose a certain amount of hydraulic pressure. Therefore, the pressure of the oil directly entering the first inner cavity 311 from the working channel 120 will be slightly greater than the pressure of the oil entering the first oil return channel 130 from the working channel 120 through the valve stem 200. Moreover, regardless of the pressure of the oil in the working channel 120, actual measurements have shown that the difference between the first pressure and the second pressure is always constant.

[0029] Therefore, by providing the first elastic member 320 to compensate for pressure loss on the right side of the first valve core 330, dynamic balance can be achieved in the oil pressure on both sides of the first valve core 330. When the first valve core 330 closes the first oil return channel 130, the oil pressure in the end of the first oil return channel 130 near the working channel 120 increases, thereby breaking the pressure balance on both sides of the first valve core 330. At this time, the oil pushes the first valve core 330 to open the first oil return channel 130, thereby achieving a new pressure balance and enabling oil backflow.

[0030] Since the pressure difference between the two ends of the first valve core 330 is fixed, the oil flow rate through the first valve core 330 is directly proportional to the throttling area of the oil. In this way, regardless of the load size at the forklift output end 700, as long as the throttling area of the oil remains unchanged, the return speed of the oil is consistent, that is, the forklift's descent speed is consistent, thereby greatly improving the controllability of the manual valve.

[0031] In one embodiment, a communication groove (not shown) extending along the axial direction of the first valve core 330 is provided on the outer peripheral side of the first valve core 330 , and the working channel 120 is connected to the first inner cavity 311 through the communication groove.

[0032] In this way, on the one hand, the difficulty of connecting the working channel 120 and the first inner cavity 311 is reduced, and on the other hand, no matter where the first valve core 330 moves axially, it can ensure that the working channel 120 and the first inner cavity 311 remain connected.

[0033] However, the present invention is not limited thereto. In other embodiments, the communication groove may also be provided in the main valve body 100 .

[0034] In one embodiment, if Figure 1 As shown, an axially extending throttling groove 210 is provided on the outer peripheral side of the valve stem 200, and the working channel 120 can be connected to the first oil return channel 130 through the throttling groove 210, and the valve stem 200 adjusts the amount of oil entering the first oil return channel 130 from the working channel 120 through the throttling groove 210.

[0035] Specifically, the throttling groove 210 is U-shaped along a cross section parallel to the axial direction of the valve stem 200 .

[0036] In one embodiment, if Figure 1 As shown, the compensation valve 300 also includes a connecting rod 340, one end of the connecting rod 340 is fixedly connected to the first valve core 330, and the other end extends toward the first inner cavity 311. The first elastic member 320 is a compression spring, and the first elastic member 320 is sleeved on the outer peripheral side of the connecting rod 340. One end of the first elastic member 320 abuts against the connecting rod 340, and the other end abuts against the first valve body 310.

[0037] With this arrangement, the first elastic member 320 has a tendency to push the connecting rod 340 to drive the first valve core 330 to open the first oil return channel 130 .

[0038] Specifically, if Figure 1 As shown, the outer peripheral side of one end of the connecting rod 340 extending into the first inner cavity 311 is provided with a first step structure 341 protruding from the surface of the connecting rod 340, and the inner wall of the first inner cavity 311 is provided with a second step structure 312 protruding from its own surface, and the two ends of the first elastic member 320 are respectively in contact with the first step structure 341 and the second step structure 312.

[0039] However, the present invention is not limited thereto. In another embodiment, the first elastic member 320 is a tension spring, and one end of the first elastic member 320 is fixedly connected to the inner wall of the first inner cavity 311 , and the other end is fixedly connected to the first valve core 330 .

[0040] In one embodiment, if Figure 1 and Figure 2As shown, the main valve body 100 is also provided with a feedback channel 160, and the valve stem 200 is provided with a process hole 220. When the manual valve is in an ascending condition, that is, when the valve stem 200 moves upward, the working channel 120 can be connected to the feedback channel 160 through the process hole 220, so that the feedback channel 160 can feedback the oil pressure of the working channel 120.

[0041] In one embodiment, if Figure 1 and Figure 2 As shown, the manual valve further includes a differential one-way valve 400 and a solenoid valve 500 . The movable end of the differential one-way valve 400 is movably disposed in the working channel 120 , and the solenoid valve 500 can control the differential one-way valve 400 to open or close the working channel 120 .

[0042] Such an arrangement is beneficial to the control efficiency of the opening and closing of the working channel 120.

[0043] Specifically, in one embodiment, Figure 1 and Figure 2 As shown, the main valve body 100 is provided with a second oil return channel 140 and a control channel 150 . The second oil return channel 140 is connected to the first oil return channel 130 . The movable end of the solenoid valve 500 is provided in the control channel 150 to open or close the control channel 150 .

[0044] The differential one-way valve 400 includes a second valve core 410 and a second elastic member 420 . The second elastic member 420 has a tendency to push the second valve core 410 to close the working channel 120 . The second valve core 410 has a second inner cavity 411 connecting the working channel 120 and the control channel 150 .

[0045] Specifically, the second elastic member 420 is a compression spring or a spring.

[0046] When the manual valve is in the descending working condition and the solenoid valve 500 opens the control channel 150, the oil in the working channel 120 can be connected to the second oil return channel 140 through the second inner cavity 411, the control channel 150 and the valve stem 200 in sequence. At this time, the second inner cavity 411 is in a pressure relief state, that is, the oil in the second inner cavity 411 has no pressure effect on the second valve core 410, and the oil in the working channel 120 can push the second valve core 410 to overcome the elastic force of the second elastic member 420 to move and open the working channel 120.

[0047] When the solenoid valve 500 closes the control channel 150 , the oil in the working channel 120 enters the second inner cavity 411 and causes the hydraulic pressure of the second inner cavity 411 to rise. In addition, the oil in the second inner cavity 411 can cooperate with the second elastic member 420 to push the second valve core 410 to close the working channel 120 .

[0048] With this configuration, when the solenoid valve 500 is de-energized, it closes the control channel 150, and the hydraulic pressure in the second inner chamber 411 of the differential check valve 400 becomes equal to the hydraulic pressure in the working channel 120. The differential check valve 400 cannot open, and the mast cannot descend. This function is a safety feature. When the solenoid valve 500 is de-energized, even if the valve stem 200 is mistakenly operated, the mast will be locked and unable to descend.

[0049] Furthermore, in one embodiment, the manual valve also includes a normally closed contact switch (not shown), the seat of the forklift cab is connected to the normally closed contact switch, and the normally closed contact switch is electrically connected to the solenoid valve 500. When the driver leaves the seat, the normally closed contact switch is in an off-state to keep the solenoid valve 500 in a closed state. When the driver sits on the seat, the normally closed contact switch is in an on-state to keep the solenoid valve 500 in a ready-to-open state. It should be noted that the solenoid valve 500 requires manual operation by the driver to open.

[0050] This arrangement further ensures the safety of the forklift and prevents the solenoid valve 500 from opening and causing the forklift to fall when the driver leaves the seat.

[0051] Specifically, if Figure 1 As shown, the manual valve further includes a bracket 600 , and the normally closed contact switch is provided on the bracket 600 .

[0052] Furthermore, in one embodiment, if Figure 1 As shown, the end of the valve stem 200 away from the compensation valve 300 extends out of the main valve body 100, and the outer peripheral side of the end of the valve stem 200 extending out of the main valve body 100 is provided with an annular groove 230 arranged around its own axial direction, and the annular groove 230 is provided with a first inclined surface 231 close to the main valve body 100, a second inclined surface 232 away from the main valve body 100, and a bottom surface 233 connecting the first inclined surface 231 and the second inclined surface 232.

[0053] When the valve stem 200 is in the middle position, the normally closed contact switch is located between the first inclined surface 231 and the second inclined surface 232 and is not in contact with the annular groove 230 , and the normally closed contact switch is in a power-off state.

[0054] When the manual valve is in a descending state, that is, when the valve stem 200 moves downward, the first inclined surface 231 can guide the normally closed contact switch.

[0055] This arrangement further ensures the safety of the forklift. At this time, as long as any one of the conditions of the driver leaving the seat and the valve stem 200 being in the neutral position is met, the normally closed contact switch is in the power-off state. At this time, the solenoid valve 500 cannot be opened and the forklift cannot be lowered.

[0056] The present application also provides a forklift, which includes the manual valve described in any one of the above embodiments.

[0057] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of patent protection for the present application shall be determined by the appended claims.

[0059] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0061] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0062] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0063] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A manual valve, characterized in that: The invention comprises a main valve body (100), a valve stem (200) and a compensation valve (300); the main valve body (100) is provided with a valve cavity (110), a working channel (120) and a first oil return channel (130); the valve stem (200) is movably arranged in the valve cavity (110); The compensating valve (300) comprises a first valve body (310), a first elastic member (320) and a first valve core (330), wherein the first valve core (330) extends from one end of the first valve body (310), one end of the first elastic member (320) is connected to the first valve body (310), and the other end is connected to the first valve core (330), so as to apply a preset pulling force to the first valve core (330) in a direction close to the first valve body (310); The end of the first valve core (330) away from the first valve body (310) can open or close the first oil return channel (130); when the manual valve is in a descending state, the working channel (120) can be connected to the first oil return channel (130) through the valve stem (200); and the oil entering the first oil return channel (130) can exert a first pressure on the end of the first valve core (330) away from the first valve body (310); The first valve body (310) is provided with a first inner cavity (311) communicating with the working channel (120), so that the oil in the working channel (120) can enter the first inner cavity (311) and exert a second pressure on an end of the first valve core (330) close to the first elastic member (320); The first pressure action, the second pressure action and the preset pulling force can enable the first valve core (330) to reach a force balance state.

2. The manual valve according to claim 1, characterized in that: It also includes a differential one-way valve (400) and a solenoid valve (500), wherein the movable end of the differential one-way valve (400) is movably arranged in the working channel (120), and the solenoid valve (500) can control the differential one-way valve (400) to open or close the working channel (120).

3. The manual valve according to claim 2, characterized in that: The main valve body (100) is provided with a second oil return channel (140) and a control channel (150), and the movable end of the solenoid valve (500) is provided in the control channel (150) to open or close the control channel (150); The differential one-way valve (400) comprises a second valve core (410) and a second elastic member (420), wherein the second elastic member (420) has a tendency to push the second valve core (410) to close the working channel (120), and the second valve core (410) is provided with a second inner cavity (411) communicating with the working channel (120) and the control channel (150); When the manual valve is in a descending state and the solenoid valve (500) opens the control channel (150), the oil in the working channel (120) can sequentially pass through the second inner cavity (411), the control channel (150) and the valve stem (200) to communicate with the second oil return channel (140), and the oil in the working channel (120) can push the second valve core (410) to overcome the elastic force of the second elastic member (420) and move to open the working channel (120); When the solenoid valve (500) closes the control channel (150), the oil in the working channel (120) can enter the second inner cavity (411) and increase the hydraulic pressure of the second inner cavity (411), and the oil in the second inner cavity (411) can cooperate with the second elastic member (420) to push the second valve core (410) to close the working channel (120).

4. The manual valve according to claim 2, characterized in that: The invention also includes a normally closed contact switch, which is electrically connected to the solenoid valve (500). When the driver leaves the seat, the normally closed contact switch is in a power-off state to keep the solenoid valve (500) in a closed state. When the driver sits on the seat, the normally closed contact switch is in a power-on state to keep the solenoid valve (500) in a ready-to-open state.

5. The manual valve according to claim 4, characterized in that: One end of the valve stem (200) away from the compensation valve (300) extends out of the main valve body (100), and an annular groove (230) arranged around the outer circumference of the end of the valve stem (200) extending out of the main valve body (100) is provided. The annular groove (230) is provided with a first inclined surface (231) close to the main valve body (100), a second inclined surface (232) away from the main valve body (100), and a bottom surface (233) connecting the first inclined surface (231) and the second inclined surface (232); When the valve stem (200) is in a neutral position, the normally closed contact switch is located between the first inclined surface (231) and the second inclined surface (232) and is not in contact with the annular groove (230), and the normally closed contact switch is in a power-off state; When the manual valve is in a descending state, the first inclined surface (231) can conduct the normally closed contact switch.

6. The manual valve according to claim 1, characterized in that The outer peripheral side of the first valve core (330) is provided with a communication groove extending along its own axial direction, and the working channel (120) is connected to the first inner cavity (311) through the communication groove.

7. The manual valve according to claim 1, characterized in that The compensation valve (300) further includes a connecting rod (340), one end of which is fixedly connected to the first valve core (330), and the other end of which extends toward the first inner cavity (311); the first elastic member (320) is a compression spring, and the first elastic member (320) is sleeved on the outer peripheral side of the connecting rod (340); one end of the first elastic member (320) abuts against the connecting rod (340), and the other end abuts against the first valve body (310).

8. The manual valve according to claim 1, characterized in that The first elastic member (320) is a tension spring, and one end of the first elastic member (320) is fixedly connected to the inner wall of the first inner cavity (311), and the other end is fixedly connected to the first valve core (330).

9. The manual valve according to claim 1, characterized in that: The main valve body (100) is further provided with a feedback channel (160), and the valve stem (200) is provided with a process hole (220). When the manual valve is in an ascending working state, the working channel (120) can be connected to the feedback channel (160) through the process hole (220), so that the feedback channel (160) can feed back the oil pressure of the working channel (120).

10. A forklift, characterized in that: Comprising a manual valve according to any one of claims 1 to 9.

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