Hydraulic system and tractor

Abstract

The utility model provides a hydraulic system and a tractor. Comprising an oil tank, a load-sensitive plunger pump, a clutch control oil way, a priority valve, a load sensing steering gear and a load-sensitive electric control valve. An oil inlet of the load-sensitive plunger pump is connected with the oil tank; the clutch control oil way comprises an oil pump connected with the load-sensitive plunger pump in parallel and a boosting oil cylinder connected with an oil outlet of the oil pump. An oil inlet of the priority valve is communicated with an oil outlet of the load-sensitive plunger pump; the load sensitive electric control valve and the load sensing steering gear are arranged in parallel through the priority valve. Oil pressure of the load sensing steering gear and the load sensitive electric control valve can be adjusted according to lifting load changes, working requirements of the hydraulic system are met, the whole hydraulic system is high in working efficiency, later maintenance of the hydraulic system is facilitated, a clutch control oil way and clutch operation arrangement are simpler and more reliable, and the service life of the hydraulic system is prolonged. And the working reliability of the clutch is ensured.

Description

Technical Field

[0001] The utility model relates to a hydraulic system for agricultural machinery, in particular to a hydraulic system and a tractor. Background Art

[0002] In the related art, the whole tractor hydraulic system shares the chassis oil for the braking system and the clutch system, and the lifting system and the steering system share the hydraulic oil and use a double - cylinder fixed - displacement pump for independent oil supply. The lifting system and the steering system are independent of each other and cannot change according to the change of the lifting load. The working efficiency of the whole hydraulic system is low. At the same time, each of the steering and lifting requires a pump to provide oil pressure for its work, which is not conducive to the cost control of the whole machine. Therefore, it is necessary to provide a hydraulic system for a tractor to overcome the defects existing above. Content of the Utility Model

[0003] The purpose of the utility model is to provide a hydraulic system and a tractor.

[0004] According to one aspect of the utility model, a hydraulic system for a tractor is provided, including: a fuel tank; a load - sensing piston pump, the inlet of the load - sensing piston pump is connected to the fuel tank; a clutch control oil circuit, the clutch control oil circuit includes an oil pump arranged in parallel with the load - sensing piston pump and a booster cylinder connected to the outlet of the oil pump; a priority valve, the inlet of the priority valve is communicated with the outlet of the load - sensing piston pump; a load - sensing steering gear, the inlet of the load - sensing steering gear is communicated with one outlet of the priority valve, and the feedback oil port of the load - sensing steering gear is communicated with the feedback oil port of the priority valve; a load - sensing electronic control valve, the load - sensing electronic control valve is connected to the other inlet of the priority valve, the return oil port of the load - sensing electronic control valve is connected to the fuel tank, and the load - sensing electronic control valve and the load - sensing steering gear are arranged in parallel.

[0005] Preferably, the clutch control oil circuit further includes a flow - dividing valve connected to the oil pump, one outlet of the flow - dividing valve is connected to the rodless cavity of the booster cylinder, and the other outlet of the flow - dividing valve is connected to a radiator.

[0006] Preferably, the rodless cavity of the booster cylinder is connected to the radiator, and the rodless cavity and the rod - less cavity of the booster cylinder are connected through a pipeline, and a solenoid valve is connected in series on this pipeline.

[0007] Preferably, the solenoid valve is controlled by a clutch pedal.

[0008] Preferably, it further includes a first shuttle valve, two inlets of the first shuttle valve are respectively communicated with the feedback oil port on the load - sensing steering gear and the feedback oil port of the load - sensing electronic control valve, and the outlet of the first shuttle valve is connected to the feedback oil port of the load - sensing piston pump.

[0009] Preferably, the load-sensitive electro-control valve includes a first reversing valve and a second reversing valve. The first reversing valve and the second reversing valve are arranged in parallel and are both connected to the outlet oil of the priority valve. The oil outlet of the first reversing valve is respectively connected to the lifting cylinder, and the oil outlet of the second reversing valve is connected to the hydraulic output joint.

[0010] Preferably, the load-sensitive electro-control valve further includes a safety valve, and the safety valve is arranged in parallel with the first reversing valve and the second reversing valve.

[0011] Preferably, the load-sensitive electro-control valve further includes a second shuttle valve and a third shuttle valve connected in series. The oil outlet of the second shuttle valve is connected to an oil inlet of the third shuttle valve. The oil outlet of the third shuttle valve is connected to an oil inlet of the next-stage third shuttle valve. The two oil inlets of the second shuttle valve and the other oil inlet of the third shuttle valve are connected to the feedback oil port of the lifting cylinder, the feedback oil port of the first reversing valve, and the feedback oil port of the second reversing valve. The oil outlet of the last-stage third shuttle valve is the feedback oil port of the load-sensitive electro-control valve.

[0012] Preferably, an oil suction filter element is connected in series on the oil inlet side of the load-sensitive piston pump, a pressure oil filter element is connected in series on the oil outlet side of the load-sensitive piston pump, and an oil return filter element is connected in series on the oil return sides of the load-sensing steering gear and the load-sensitive electro-control valve.

[0013] According to another aspect of the present invention, a tractor is provided, including the hydraulic system.

[0014] Compared with the prior art, the hydraulic system and the tractor provided by the present invention have the following beneficial effects:

[0015] On the one hand, in the present invention, the load-sensing steering gear and the load-sensitive electro-control valve share a common fuel tank and are powered by a load-sensitive piston pump, and a priority valve is connected in the hydraulic system. It can adjust the oil pressure of the load-sensing steering gear and the load-sensitive electro-control valve according to the change of the lifting load to meet their working requirements. The whole hydraulic system has high working efficiency, fast response, high reliability, low cost, and is beneficial to the later maintenance and servicing of the hydraulic system.

[0016] On the other hand, the clutch control oil circuit of the present invention adopts a hydraulic assist structure and uses different fuel tanks from the brake control oil circuit, making the clutch control oil circuit and the clutch operating arrangement simpler and more reliable, greatly reducing the cost, having high oil circuit cleanliness, and being beneficial to ensuring the reliability of the clutch operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0018] Figure 1This is the hydraulic schematic diagram of the present utility model.

[0019] Description of reference numerals: 1, fuel tank; 2, load-sensitive piston pump; 3, clutch control oil circuit; 4, priority valve; 5, load-sensing steering gear; 6, load-sensitive electronic control valve; 7, first shuttle valve; 31, oil pump; 32, flow dividing valve; 33, solenoid valve; 34, booster cylinder; 35, radiator; 61, first reversing valve; 611, lifting valve; 612, lowering valve; 62, second reversing valve; 63, safety valve; 64, second shuttle valve; 65, third shuttle valve; 66, lifting cylinder; 67, hydraulic output joint; 81, suction oil filter element; 82, pressure oil filter element; 83, return oil filter element. Detailed implementation manners

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] To make the drawings concise, only the parts related to the present utility model are schematically shown in each drawing, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, parts with the same structure or function are only schematically shown for one of them, or only one of them is marked. In this article, "one" not only means "only this one", but also means the situation of "more than one".

[0022] It should be further understood that the term "and / or" used in the description of this application and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0023] In this article, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0024] In addition, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will describe the specific embodiments of the present invention with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other embodiments can also be obtained.

[0026] Refer to Figure 1 , this embodiment provides a hydraulic system for a tractor, including: a fuel tank 1, a load-sensitive piston pump 2, a clutch control oil circuit 3, a priority valve 4, a load-sensing steering gear 5, and a load-sensitive electro-hydraulic valve 6.

[0027] The fuel tank 1 is a lifting hydraulic fuel tank 1. The load-sensitive piston pump 2 is connected to the fuel tank 1. The load-sensitive piston pump 2 is a variable pump and supplies oil to the load-sensing steering gear 5 and the load-sensitive electro-hydraulic valve 6. The oil pump 31 is connected to the fuel tank 1 and is arranged in parallel with the load-sensitive piston pump 2. The oil pump 31 is a fixed-displacement pump, preferably a gear pump, and supplies oil to the clutch control oil circuit 3.

[0028] The clutch control oil circuit 3 includes an oil pump 31 arranged in parallel with the load-sensitive piston pump 2, a flow dividing valve 32 connected to the oil pump 31, and an assist cylinder 34 connected to the oil outlet of the oil pump 31 through the flow dividing valve 32. One oil outlet of the flow dividing valve 32 is connected to the rod chamber of the assist cylinder 34, and the clutch is controlled through the assist cylinder 34. In this way, the clutch control oil circuit 3 adopts a hydraulic assist structure and uses different fuel tanks 1 from the brake control oil circuit respectively. The clutch control oil circuit 3 and the clutch operating arrangement are more concise and reliable, the cost is greatly reduced, the cleanliness of the oil circuit is high, which is conducive to ensuring the reliability of the clutch operation.

[0029] Another oil outlet of the flow dividing valve 32 is connected to the radiator 35, and the rodless chamber of the assist cylinder 34 is also connected to the radiator 35. The rod chamber and the rodless chamber of the assist cylinder 34 are connected through a pipeline, and a solenoid valve 33 is connected in series on this pipeline. The solenoid valve 33 is controlled by the clutch pedal, and the on-off of the solenoid valve 33 is controlled through the clutch pedal. When there is no force on the clutch pedal, the solenoid valve 33 remains connected, and the hydraulic oil passing through the assist cylinder 34 converges with another part of the hydraulic oil and flows to the radiator 35. When stepping on the clutch pedal, the rod chamber and the rodless chamber are not connected, and the hydraulic oil flows to the rod chamber of the assist cylinder 34. The hydraulic oil pushes the piston rod of the assist cylinder 34 to retract, and the piston rod drives the clutch to disengage. When the piston rod reaches the limit position, the rod chamber of the assist cylinder 34 will no longer receive oil, and the hydraulic oil directly flows to the radiator 35.

[0030] The oil inlet of the load sensing steering gear 5 is communicated with an oil outlet of the priority valve 4, and the feedback oil port of the load sensing steering gear 5 is communicated with the feedback oil port of the priority valve 4. The load sensitive electronic control valve 6 is communicated with another oil inlet of the priority valve 4, and the oil return port of the load sensitive electronic control valve 6 is connected to the fuel tank 1, and the load sensitive electronic control valve 6 and the load sensing steering gear 5 are arranged in parallel.

[0031] In this embodiment, the load sensing steering gear 5 and the load sensitive electronic control valve 6 are powered by a shared oil and a load sensitive piston pump 2, and a priority valve 4 is connected into the hydraulic system, which can adjust the oil pressure of the load sensing steering gear 5 and the load sensitive electronic control valve 6 according to the change of the lifting load to meet their working requirements. The whole hydraulic system has high working efficiency, fast response, high reliability, low cost, and is beneficial to the later maintenance of the hydraulic system.

[0032] The load sensing steering gear 5 and the load sensitive electronic control valve 6 are connected to the load sensitive piston pump 2 through a first shuttle valve 7. The two oil inlets of the first shuttle valve 7 are respectively communicated with the feedback oil port on the load sensing steering gear 5 and the feedback oil port of the load sensitive electronic control valve 6, and the oil outlet of the first shuttle valve 7 is connected to the feedback oil port of the load sensitive piston pump 2.

[0033] The load sensitive electronic control valve 6 includes a first reversing valve 61, a second reversing valve 62 and a safety valve 63. The first reversing valve 61 and the second reversing valve 62 are arranged in parallel and are both connected to the outlet oil of the priority valve 4. The oil outlet of the first reversing valve 61 is respectively connected to the lifting cylinder 66, and the oil outlet of the second reversing valve 62 is connected to the hydraulic output joint 67. The safety valve 63 is arranged in parallel with the first reversing valve 61 and the second reversing valve 62 to realize system pressure relief and ensure that the internal pressure of the multi-way valve does not exceed the specified value.

[0034] The lifting cylinder 66 corresponding to the first reversing valve 61 can be a double-acting cylinder, or the lifting cylinder 66 corresponding to the first reversing valve 61 can be a single-acting cylinder. For those skilled in the art, there are various conventional structure selections for the first reversing valve 61 and the second reversing valve 62.

[0035] In this embodiment, taking the single-acting cylinder as an example for illustration, the first reversing valve 61 includes a lifting valve 611 and a lowering valve 612. During the lifting process, the lifting valve 611 is opened, and the lifting valve 611 unidirectionally introduces hydraulic oil into the rodless cavity of the lifting cylinder 66. During the lowering process, the lifting cylinder 66 descends under the action of the load, the lowering valve 612 is opened, and the lowering valve 612 unidirectionally discharges the hydraulic oil to the fuel tank 1.

[0036] The load-sensitive electro-control valve 6 further includes a second shuttle valve 64 and a third shuttle valve 65 connected in series in sequence. The oil outlet of the second shuttle valve 64 is connected to an oil inlet of the third shuttle valve 65, and the oil outlet of the third shuttle valve 65 is connected to an oil inlet of the next-level third shuttle valve 65. The two oil inlets of the second shuttle valve 64, the other oil inlet of the third shuttle valve 65, the feedback oil port of the lifting cylinder 66, the feedback oil port of the first reversing valve 61, and the feedback oil port of the second reversing valve 62. The number of the third shuttle valves 65 is adapted to the number of feedback oil ports to be detected. The oil outlet of the last-level third shuttle valve 65 is the feedback oil port of the load-sensitive electro-control valve 6, and the maximum pressure in the load-sensitive electro-control valve 6 is conducted to the feedback oil port of the load-sensitive electro-control valve 6.

[0037] An oil suction filter element 81 is connected in series on the oil inlet side of the load-sensitive piston pump 2, a pressure oil filter element 82 is connected in series on the oil outlet side of the load-sensitive piston pump 2, and an oil return filter element 83 is connected in series on the oil return sides of the load-sensing steering gear 5 and the load-sensitive electro-control valve 6 to ensure the cleanliness of the entire hydraulic system.

[0038] It will be apparent to those skilled in the art that various modifications and variations can be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention cover modifications and variations of the present invention falling within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A hydraulic system for a tractor, characterized in that, Comprising: Fuel tank; Load-sensing piston pump, the inlet of which is connected to the fuel tank; Clutch control oil circuit, the clutch control oil circuit includes an oil pump arranged in parallel with the load-sensing piston pump and a booster cylinder connected to the outlet of the oil pump; Priority valve, the inlet of which is communicated with the outlet of the load-sensing piston pump; Load-sensing steering gear, the inlet of which is communicated with one outlet of the priority valve, and the feedback oil port of the load-sensing steering gear is communicated with the feedback oil port of the priority valve; Load-sensing electro-control valve, which is connected to the other inlet of the priority valve, the return oil port of which is connected to the fuel tank, and the load-sensing electro-control valve and the load-sensing steering gear are arranged in parallel.

2. The hydraulic system for a tractor according to claim 1, characterized in that, The clutch control oil circuit further includes a flow dividing valve connected to the oil pump, one outlet of the flow dividing valve is connected to the rodless cavity of the booster cylinder, and the other outlet of the flow dividing valve is connected to the radiator.

3. The hydraulic system for a tractor according to claim 2, characterized in that, The rodless cavity of the booster cylinder is connected to the radiator, and the rodless cavity and the rodless cavity of the booster cylinder are connected by a pipeline, and a solenoid valve is connected in series on this pipeline.

4. The hydraulic system for a tractor according to claim 3, characterized in that, The solenoid valve is controlled by the clutch pedal.

5. The hydraulic system for a tractor according to claim 4, characterized in that, It further includes a first shuttle valve, the two inlets of which are respectively communicated with the feedback oil port on the load-sensing steering gear and the feedback oil port of the load-sensing electro-control valve, and the outlet of the first shuttle valve is connected to the feedback oil port of the load-sensing piston pump.

6. The hydraulic system for a tractor according to claim 5, characterized in that, The load-sensing electro-control valve includes a first reversing valve and a second reversing valve, the first reversing valve and the second reversing valve are arranged in parallel and are both connected to the outlet oil of the priority valve, the outlet of the first reversing valve is respectively connected to the lifting cylinder, and the outlet of the second reversing valve is connected to the hydraulic output joint.

7. The hydraulic system for a tractor according to claim 6, characterized in that, The load-sensing electro-control valve further includes a safety valve, which is arranged in parallel with the first reversing valve and the second reversing valve.

8. The hydraulic system for a tractor according to claim 7, characterized in that, The load-sensing electro-control valve further includes a second shuttle valve and a third shuttle valve connected in series in sequence, the outlet of the second shuttle valve is connected to one inlet of the third shuttle valve, the outlet of the third shuttle valve is connected to one inlet of the next-level third shuttle valve, the two inlets of the second shuttle valve and the other inlet of the third shuttle valve are connected to the feedback oil port of the lifting cylinder, the feedback oil port of the first reversing valve, the feedback oil port of the second reversing valve, and the outlet of the last-level third shuttle valve is the feedback oil port of the load-sensing electro-control valve.

9. The hydraulic system for a tractor according to claim 8, characterized in that, An oil suction filter element is connected in series on the inlet side of the load-sensing piston pump, a pressure oil filter element is connected in series on the outlet side of the load-sensing piston pump, and a return oil filter element is connected in series on the return oil sides of the load-sensing steering gear and the load-sensing electro-control valve.

10. A tractor, characterized in that, Including the hydraulic system for tractor according to any one of claims 1 to 9.

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