Load-sensitive multi-way valve for tractor

Abstract

The utility model discloses a load-sensitive multi-way valve for a tractor. The problems that pressure oil on an existing agricultural machine cannot be stored, oil leakage exists, and pressure is not stable are solved. The hydraulic control valve comprises a valve body, an oil inlet, a feedback oil way, an oil return opening, a first oil way and a pilot hydraulic lock. The pilot hydraulic lock comprises a first hydraulic lock and a pilot valve, and the first hydraulic lock is arranged on the first oil way; the first hydraulic lock comprises an interlocking block and a hydraulic control cavity, and the interlocking block has a first state for blocking the first oil way during installation and a second state for opening to enable the first oil way to be communicated; a hydraulic lock elastic piece is arranged in the hydraulic control cavity, and elastic force of the hydraulic lock elastic piece and / or pressure oil in the hydraulic control cavity are / is matched with each other to enable the interlocking block to tend to be in a first state. The first hydraulic lock and the pilot valve are arranged, and the first hydraulic lock can lock the first oil way, so that the pressure of the agricultural machinery can be maintained during transferring and working, the pressure of the product is constant, and the effect is good.

Description

Technical Field

[0001] The utility model relates to a hydraulic control system for a tractor, in particular to a load-sensitive multi-way valve for a tractor. Background Art

[0002] Agricultural machinery refers to various machines used in the production process of crop planting and animal husbandry, as well as in the primary processing and treatment of agricultural and livestock products. Agricultural machinery includes agricultural power machinery, farmland construction machinery, soil tillage machinery, planting and fertilizing machinery, plant protection machinery, farmland irrigation and drainage machinery, crop harvesting machinery, agricultural product processing machinery, animal husbandry machinery and agricultural transportation machinery. At present, there is a kind of agricultural machinery on the market, such as agricultural tractors, which usually have to realize functions such as sowing, lifting and flipping of agricultural tools. The action of the tractor is controlled by a hydraulic system. Load-sensitive multi-way valves are very common in engineering machinery, but they are not used much in the agricultural machinery industry. The existing multi-way valves in the agricultural machinery industry usually use manual control reversing, which is difficult to operate and has low operating accuracy. Traditional multi-way valves cannot guarantee accurate flow control and control of the position of the reversing valve, and need to add pilot pressure reducing valves, proportional pressure reducing valves used in each working connection to drive the reversing valve, and many complex pilot control oil circuits, and the structure is relatively simple and complex. In order to maintain the position or working state of agricultural implements, hydraulic locks are usually set. However, many existing agricultural machinery have high sealing requirements. For example, the lifting cylinder of a tractor requires high pressure retention performance. If the pressure retention performance is not good, the plowing depth will be different when plowing, affecting the plowing effect. When moving sites, if the plow cannot be supported for a long time, the site cannot be changed. However, after the existing agricultural machinery is lifted into place, there are practical problems such as oil leakage, inability to lock, and inability to reliably maintain pressure. Utility Model Content

[0003] In order to solve the problems in the prior art that the pressure oil on the existing agricultural machinery cannot be preserved, there is oil leakage and the pressure is unstable, the utility model provides a load-sensitive multi-way valve for a tractor.

[0004] The technical solution of the utility model is: a load-sensitive multi-way valve for a tractor, comprising a valve body, an oil inlet, a feedback oil circuit and an oil return port, and also comprising:

[0005] A first oil circuit is provided in the valve body;

[0006] A first working oil port is provided on the valve body and is connected to the first oil circuit;

[0007] A first reversing valve stem is disposed in the valve body;

[0008] Oil inlet union, used for oil inlet or oil return;

[0009] A first working joint, wherein a pilot hydraulic lock is provided on the first working joint; the pilot hydraulic lock comprises a first hydraulic lock and a pilot valve, wherein the first hydraulic lock is provided on a first oil circuit; the first hydraulic lock comprises an interlocking block and a hydraulic control chamber, wherein the interlocking block has a state of blocking the first oil circuit when installed and a second state of being opened so as to connect the first oil circuit; a hydraulic lock elastic member is provided in the hydraulic control chamber, wherein the elastic force of the hydraulic lock elastic member and / or the pressure oil in the hydraulic control chamber cooperate with each other so that the interlocking block tends to the first state; the pilot valve is provided on the valve body, wherein the hydraulic control chamber is connected to the oil return port after the pilot valve is opened;

[0010] A second working link is arranged in parallel with the first working link; the second working link is provided with a second reversing valve stem;

[0011] The first working joint and the second working joint are both provided with pressure compensators; the pressure oil at the oil inlet is fed back to the feedback oil circuit after passing through the pressure compensator.

[0012] As a further improvement of the utility model, the first hydraulic lock is provided with a connecting hole, the connecting hole is provided with a first damping hole, and the first oil circuit is connected to the hydraulic control chamber through the connecting hole and the first damping hole.

[0013] As a further improvement of the utility model, the pilot valve includes a push rod and a pilot valve block. A pilot valve ball is provided in the pilot valve block. The pilot valve ball has a first position for blocking the return of pressure oil in the hydraulic control chamber and a second position for being opened by the push rod so that the pressure oil in the hydraulic control chamber is connected to the return oil port.

[0014] As a further improvement of the utility model, a first arc-shaped portion is provided on the first reversing valve stem, and the first arc-shaped portion abuts against the push rod and opens the pilot valve ball through the push rod so that the pressure oil in the hydraulic control chamber is connected to the oil return port.

[0015] As a further improvement of the utility model, the oil inlet unit comprises:

[0016] The main overflow valve is located between the oil inlet and the oil return port;

[0017] A hydraulically controlled reversing valve is arranged between the oil inlet and the oil return port; the spring chamber of the hydraulically controlled reversing valve is connected to the feedback oil circuit;

[0018] Feedback relief valve; arranged between the feedback oil circuit and the oil return port, the opening pressure of the feedback relief valve is less than the opening pressure of the main relief valve.

[0019] As a further improvement of the utility model, it also includes:

[0020] Constant flow valve, located between the feedback oil circuit and the return oil port

[0021] The second damping hole is arranged between the spring chamber of the hydraulically controlled reversing valve and the feedback oil circuit; the opening pressure of the hydraulically controlled reversing valve is greater than the opening pressure of the pressure compensator.

[0022] As a further improvement of the utility model, it also includes a throttle valve, which is arranged on the valve body. The pressure oil at the oil outlet of the pressure compensator passes through the first reversing valve stem to the throttle valve and then flows to the feedback oil circuit and the first working oil port.

[0023] As a further improvement of the utility model, the throttle valve includes a throttle sleeve, a throttle rod and an adjusting piece. The throttle sleeve is arranged on the valve body and is detachably connected to the valve body. The adjusting piece is connected to the throttle sleeve through the throttle rod and adjusts the size of the throttle valve opening through the throttle rod.

[0024] As a further improvement of the utility model, the second working joint is provided with a unloading valve and a switching valve, the oil inlet is connected to the pressure compensator through the unloading valve, and the switching valve is arranged between the second working oil port and the oil return port; the switching valve has a first closed position and a second position that connects the second working oil port with the oil return port.

[0025] As a further improvement of the utility model, the first working joint has at least two joints, the first working joint adopts manual and / or electric control of the movement of the first reversing valve stem, and the second working joint adopts electric control of the second reversing valve stem.

[0026] The beneficial effect of the utility model is that the first hydraulic lock and the pilot valve are provided, the first hydraulic lock can lock the first oil circuit, so that the first working oil port is maintained and does not leak, so that the agricultural machinery can maintain pressure during transfer and operation, thereby making the product pressure constant and having a good effect. The first reversing valve stem can open the pilot valve, so that the first hydraulic lock can quickly drain oil and has a strong oil flow capacity. The utility model also has the advantages of simple structure, convenient assembly, reliable action, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Attached Figure 1 It is a schematic diagram of the hydraulic principle of an embodiment of the utility model.

[0028] Attached Figure 2 It is a schematic diagram of the hydraulic principle of the oil inlet connection of an embodiment of the utility model.

[0029] Attached Figure 3 This is a schematic diagram of the structure of the first working unit of an embodiment of the utility model.

[0030] Attached Figure 4 For attachment Figure 3 Schematic diagram of the enlarged structure at I in the middle.

[0031] Attached Figure 5This is a hydraulic principle diagram of the first working joint of an embodiment of the utility model.

[0032] Attached Figure 6 This is a hydraulic principle diagram of the second working joint of an embodiment of the utility model.

[0033] In the figure, 1, valve body; 11, first oil circuit; 12, first working oil port; 13, first reversing valve stem; 131, first arc-shaped portion; 2, oil inlet link; 21, main relief valve; 22, hydraulic control reversing valve; 23, feedback relief valve; 24, second damping hole; 25, constant flow valve; 3, first working link; 4, pilot hydraulic lock; 41, first hydraulic lock; 411, interlocking block; 412, hydraulic control chamber; 413, hydraulic lock elastic member ; 414, connecting hole; 415, first damping hole; 42, pilot valve; 421, push rod; 422, pilot valve block; 423, pilot valve ball; 5, second working link; 51, second reversing valve stem; 52, unloading valve; 53, switching valve; 54, second working oil port; 6, pressure compensator; 7, throttle valve; 71, throttle sleeve; 72, throttle rod; 73, adjusting part; P, oil inlet; LS, feedback oil circuit; T, oil return port. DETAILED DESCRIPTION

[0034] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings:

[0035] Depend on Figure 1 Combination Figure 2-6 As shown, a load-sensing multi-way valve for a tractor includes a valve body 1, an oil inlet P, a feedback oil circuit LS and an oil return port T, and also includes:

[0036] The first oil circuit 11 is provided in the valve body 1;

[0037] The first working oil port 12 is provided on the valve body 1 and connected to the first oil passage 11;

[0038] A first reversing valve stem 13 is disposed in the valve body 1;

[0039] Oil inlet 2, used for oil inlet or oil return;

[0040] A first working link 3, wherein a pilot hydraulic lock 4 is provided on the first working link 3; the pilot hydraulic lock 4 comprises a first hydraulic lock 41 and a pilot valve 42, wherein the first hydraulic lock 41 is provided on the first oil circuit 11; the first hydraulic lock 41 comprises an interlocking block 411 and a hydraulic control chamber 412, wherein the interlocking block 411 has a state of blocking the first oil circuit 11 when installed and a second state of being opened so as to connect the first oil circuit 11; a hydraulic lock elastic member 413 is provided in the hydraulic control chamber 412, wherein the elastic force of the hydraulic lock elastic member 413 and / or the pressure oil in the hydraulic control chamber 412 cooperate with each other so that the interlocking block tends to the first state; the pilot valve 42 is provided on the valve body 1, wherein the hydraulic control chamber 412 is connected to the oil return port T after the pilot valve 42 is opened;

[0041] The second working link 5 is arranged in parallel with the first working link 3; the second working link 5 is provided with a second reversing valve stem 51;

[0042] The first working joint 3 and the second working joint 5 are both provided with a pressure compensator 6; the pressure oil of the oil inlet P is fed back to the feedback oil circuit LS after passing through the pressure compensator 6. The beneficial effect of the utility model is that a first hydraulic lock and a pilot valve are provided, and the first hydraulic lock can lock the first oil circuit so that the first working oil port is maintained and does not leak, so that the agricultural machinery can maintain pressure during transfer and operation, thereby making the product pressure constant and having a good effect. The first reversing valve stem can open the pilot valve, so that the first hydraulic lock can quickly drain oil and has a strong oil flow capacity. The utility model also has the advantages of simple structure, convenient assembly, reliable operation, and long service life. In order to reduce the energy loss of the system in the standby state, when the working joint is not working, the pressure oil at the P port pushes the hydraulically controlled reversing valve to make it in an open state, and the oil returns to the oil tank through the hydraulically controlled reversing valve. The opening pressure of the hydraulically controlled reversing valve is very small, which can greatly reduce the energy loss in the standby state. When the electronically controlled working joint (second working joint) is working, the electronic actuator controls the reversing of the second reversing valve stem, and the pressure compensator ensures that the pressure difference before and after the reversing valve sensing port remains unchanged. The flow rate of the second working port is determined by the size of the reversing valve sensing port and has nothing to do with the workload. The excess flow returns to the oil tank from the oil inlet reversing valve. When the electronically controlled working joint unloading valve is working, the pressure compensator is closed, and the pressure oil cannot reach the second reversing valve stem. All the pressure oil enters other working joints that require large flow. The working state of the second joint does not affect other working joints (first working joint). Generally speaking, the second working joint is used to control the lifting of agricultural implements.

[0043] The first hydraulic lock 41 is provided with a connecting hole 414, the connecting hole 414 is provided with a first damping hole 415, and the first oil circuit 11 is connected to the hydraulic control chamber 412 through the connecting hole 414 and the first damping hole 415. Such a structure enables the first hydraulic lock to be locked reliably, thereby ensuring that the hydraulic lock is locked reliably.

[0044] The pilot valve 42 includes a push rod 421 and a pilot valve block 422. A pilot valve ball 423 is provided in the pilot valve block 422. The pilot valve ball 423 has a first position for blocking the return of the pressure oil in the hydraulic control chamber 412 and a second position for being opened by the push rod so that the pressure oil in the hydraulic control chamber 412 is connected to the return oil port T. Specifically, a first arc portion 131 is provided on the first reversing valve stem 13. The first arc portion 131 abuts against the push rod 421 and opens the pilot valve ball 423 through the push rod 421 so that the pressure oil in the hydraulic control chamber 412 is connected to the return oil port T. The utility model can realize the opening of the first hydraulic lock through the reversal of the valve stem, has a fast response, a large flow rate, and a rapid reaction, and is suitable for the hydraulic system of a high-horsepower tractor.

[0045] The oil inlet 2 comprises:

[0046] The main relief valve 21 is provided between the oil inlet P and the oil return port T;

[0047] The hydraulically controlled reversing valve 22 is arranged between the oil inlet P and the oil return port T; the spring chamber of the hydraulically controlled reversing valve is connected to the feedback oil circuit LS;

[0048] Feedback relief valve 23; arranged between feedback oil circuit LS and oil return port T, the opening pressure of the feedback relief valve 23 is less than the opening pressure of the main relief valve 21. The utility model is equipped with a main relief valve and a feedback relief valve, which are used to limit the maximum working pressure of the whole valve and the feedback oil circuit to ensure the safety of the system. The utility model is equipped with a hydraulically controlled reversing valve. In the quantitative pump system, the flow entering the valve directly returns to the oil tank through the hydraulically controlled reversing valve at a very low pressure, reducing unnecessary energy loss; at the same time, a pressure difference is provided for the pressure compensator to ensure a constant working joint flow. In the variable pump system, when the flow required at the working port suddenly decreases and the pump response speed is relatively lagging, the flow is directly returned to the oil tank to protect the system.

[0049] The utility model also includes:

[0050] The constant flow valve 25 is installed between the feedback oil circuit LS and the oil return port T.

[0051] The second damping hole 24 is arranged between the hydraulic control reversing valve spring chamber and the feedback oil circuit LS; the opening pressure of the hydraulic control reversing valve 22 is greater than the opening pressure of the pressure compensator 6. Such a structure ensures the normal operation of the pressure compensator and also makes the system more stable.

[0052] The utility model also includes a throttle valve 7, which is arranged on the valve body 1. The pressure oil at the oil outlet of the pressure compensator 6 flows to the feedback oil circuit LS and the first working oil port 12 after passing through the first reversing valve stem 13 to the throttle valve 7. Specifically, the throttle valve 7 includes a throttle sleeve 71, a throttle rod 72 and an adjusting member 73. The throttle sleeve 71 is arranged on the valve body 1 and is detachably connected to the valve body 1. The adjusting member 73 is connected to the throttle sleeve 71 through the throttle rod 72 and adjusts the opening size of the throttle valve 7 through the throttle rod 72. The inlet flow rate can be adjusted by setting the throttle valve, and the structure is simple, and the adjustment is convenient and reliable.

[0053] The second working link 5 is provided with an unloading valve 52 and a switching valve 53. The oil inlet P is connected to the pressure compensator 6 through the unloading valve 52. The switching valve 53 is arranged between the second working oil port 54 and the oil return port T. The switching valve 53 has a first position of closing and a second position of connecting the second working oil port 54 with the oil return port T. When the unloading valve of the second working link is working, the pressure compensator is closed, the pressure oil cannot reach the second reversing valve stem, and all the pressure oil enters other working links that require a large flow. The working state of the second link does not affect other working links (the first working link).

[0054] The first working link 3 has at least two links, the first working link 3 uses manual and / or electric control to move the first reversing valve rod 13, and the second working link 5 uses electric control to move the second reversing valve rod 51. Usually, the second working link is used to drive the agricultural implement to rise and fall, and the first working link has multiple links, which can drive the agricultural implement to rotate or do other actions.

[0055] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0056] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, in the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0057] Technical personnel should note: Although the utility model has been described according to the above specific implementation methods, the utility model concept is not limited to this utility model. Any modification using the utility model concept will be included in the scope of protection of the utility model patent right.

Claims

1. A load-sensitive multi-way valve for a tractor, comprising a valve body (1), an oil inlet (P), a feedback oil circuit (LS) and an oil return port (T), characterized in that Also included: A first oil circuit (11) is provided in the valve body (1); A first working oil port (12) is provided on the valve body (1) and is connected to the first oil passage (11); A first reversing valve stem (13) is disposed in the valve body (1); Oil inlet (2), used for oil inlet or oil return; A first working joint (3), wherein a pilot hydraulic lock (4) is provided on the first working joint (3); the pilot hydraulic lock (4) comprises a first hydraulic lock (41) and a pilot valve (42), wherein the first hydraulic lock (41) is provided on the first oil circuit (11); the first hydraulic lock (41) comprises an interlocking block (411) and a hydraulic control chamber (412), wherein the interlocking block (411) has a state of blocking the first oil circuit (11) when installed and a second state of being opened to allow the first oil circuit (11) to be connected; a hydraulic lock elastic member (413) is provided in the hydraulic control chamber (412), wherein the elastic force of the hydraulic lock elastic member (413) and / or the pressure oil in the hydraulic control chamber (412) cooperate with each other to make the interlocking block tend to the first state; the pilot valve (42) is provided on the valve body (1), wherein the hydraulic control chamber (412) is connected to the oil return port (T) when the pilot valve (42) is opened; A second working link (5) is arranged in parallel with the first working link (3); a second reversing valve stem (51) is provided on the second working link (5); The first working joint (3) and the second working joint (5) are both provided with a pressure compensator (6); the pressure oil at the oil inlet (P) passes through the pressure compensator (6) and then is fed back to the feedback oil circuit (LS).

2. A load-sensing multi-way valve for a tractor according to claim 1, characterized in that The first hydraulic lock (41) is provided with a connecting hole (414), the connecting hole (414) is provided with a first damping hole (415), and the first oil circuit (11) is connected to the hydraulic control chamber (412) via the connecting hole (414) and the first damping hole (415).

3. A load-sensing multi-way valve for a tractor according to claim 1, characterized in that The pilot valve (42) comprises a push rod (421) and a pilot valve block (422). A pilot valve ball (423) is arranged in the pilot valve block (422). The pilot valve ball (423) has a first position for blocking the return of pressure oil in the hydraulic control chamber (412) and a second position for being opened by the push rod so that the pressure oil in the hydraulic control chamber (412) is connected to the return oil port (T).

4. A load-sensing multi-way valve for a tractor according to claim 3, characterized in that The first reversing valve stem (13) is provided with a first arc-shaped portion (131), which abuts against the push rod (421) and opens the pilot valve ball (423) through the push rod (421), so that the pressure oil in the hydraulic control chamber (412) is connected to the oil return port (T).

5. A load-sensing multi-way valve for a tractor according to claim 1, characterized in that The oil inlet (2) comprises: A main relief valve (21) is provided between the oil inlet (P) and the oil return port (T); A hydraulically controlled reversing valve (22) is arranged between the oil inlet (P) and the oil return port (T); a spring chamber of the hydraulically controlled reversing valve is connected to a feedback oil circuit (LS); A feedback relief valve (23) is provided between the feedback oil circuit (LS) and the oil return port (T), wherein the opening pressure of the feedback relief valve (23) is lower than the opening pressure of the main relief valve (21).

6. A load sensing multi-way valve for tractors according to claim 5, characterized in that Also includes: The constant flow valve (25) is installed between the feedback oil circuit (LS) and the return oil port (T). The second damping hole (24) is arranged between the spring chamber of the hydraulically controlled reversing valve and the feedback oil circuit (LS); the opening pressure of the hydraulically controlled reversing valve (22) is greater than the opening pressure of the pressure compensator (6).

7. A load sensing multi-way valve for a tractor according to claim 1, characterized in that It also includes a throttle valve (7) disposed on the valve body (1), and the pressure oil at the oil outlet of the pressure compensator (6) flows through the first reversing valve stem (13) to the throttle valve (7) and then flows to the feedback oil circuit (LS) and the first working oil port (12).

8. A load sensing multi-way valve for a tractor according to claim 7, characterized in that The throttle valve (7) comprises a throttle sleeve (71), a throttle rod (72) and an adjusting member (73); the throttle sleeve (71) is arranged on the valve body (1) and is detachably connected to the valve body (1); the adjusting member (73) is connected to the throttle sleeve (71) via the throttle rod (72) and adjusts the opening size of the throttle valve (7) via the throttle rod (72).

9. A load sensing multi-way valve for a tractor according to claim 1, characterized in that The second working joint (5) is provided with a relief valve (52) and a switching valve (53); the oil inlet (P) is connected to the pressure compensator (6) via the relief valve (52); the switching valve (53) is arranged between the second working oil port (54) and the oil return port (T); the switching valve (53) has a first position in which it is closed and a second position in which the second working oil port (54) is connected to the oil return port (T).

10. A load sensing multi-way valve for a tractor according to claim 1, characterized in that The first working link (3) has at least two links. The first working link (3) uses manual and / or electric control to control the movement of the first reversing valve stem (13), and the second working link (5) uses electric control to control the second reversing valve stem (51).

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