Hydraulic control system and power shifting tractor

Abstract

The invention belongs to the technical field of agricultural machinery, and discloses a hydraulic control system and a power gear shifting tractor. The hydraulic system comprises a working accessory hydraulic loop which comprises an accessory controller; a PTO clutch and a reversing clutch are arranged in the gearbox; the control valve group comprises a PTO clutch control valve and a reversing control valve; the hydraulic pump set is used for pumping oil from a gearbox pump and comprises a first pump and a second pump; the first oil way is hydraulically connected between the oil return port of the accessory controller and the oil return port of the PTO clutch control valve; and the second oil way is hydraulically connected between the oil return port of the PTO clutch control valve and the gearbox, so that the return oil liquid of the accessory controller and the return oil liquid of the PTO clutch control valve are converged to the gearbox to be used as lubricating oil liquid. The working performance of the hydraulic control system can be improved and promoted, the valve is prevented from being impacted by back pressure, the service life of the valve is prolonged, the lubricating flow is large, a clutch in a gearbox is lubricated more sufficiently, and clutch model selection is wider.

Description

Technical Field

[0001] This application belongs to the field of agricultural machinery technology, specifically relating to a tractor and its hydraulic control system. Background Technology

[0002] like Figure 1 As shown, in existing tractors, the gearbox contains a common oil. The return oil from the steering controller (referred to as the steering gear) passes through the radiator and then controls the reversing valve and the PTO clutch control valve. Finally, the return oil from the PTO clutch control valve provides lubrication flow to the PTO clutch and reversing clutch in the gearbox.

[0003] When using this lubrication supply method, the lubrication flow for the reversing clutch and PTO clutch is provided solely by the steering pump. Insufficient lubrication flow will reduce the service life of the reversing clutch and PTO clutch, and the increased oil temperature will affect the transmission and the entire shared hydraulic system. This limits the types of reversing clutches and PTO clutches that can be used in the transmission, restricting the selection to clutches with low required lubrication flow. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies, this application discloses a hydraulic control system and a power shift tractor to improve and enhance the working performance of the hydraulic control system.

[0005] To achieve the above objectives, this application provides a hydraulic control system for a power shift tractor, the hydraulic system comprising: The hydraulic circuit for the working attachment, including the attachment controller; The gearbox includes a PTO clutch and a reversing clutch. The control valve assembly includes a PTO clutch control valve for controlling the on / off state of the PTO clutch and a reversing control valve for controlling the on / off state of the reversing clutch. A hydraulic pump assembly for drawing hydraulic fluid from the gearbox pump and including a first pump pumping hydraulic fluid toward the inlet of the attachment controller and a second pump pumping hydraulic fluid toward the inlet of the PTO clutch control valve and the inlet of the reversing control valve. The first oil circuit is hydraulically connected between the return port of the attachment controller and the return port of the PTO clutch control valve. The second oil circuit is hydraulically connected between the return port of the PTO clutch control valve and the gearbox, so that the return oil from the attachment controller and the return oil from the PTO clutch control valve flow into the gearbox to be used as lubricating oil for the PTO clutch and the reversing clutch.

[0006] In some embodiments, the return oil of the reversing control valve is hydraulically connected to the second oil circuit, so that the return oil of the reversing control valve flows into the gearbox as the lubricating oil.

[0007] In some embodiments, a radiator is provided in the first oil circuit.

[0008] In some embodiments, the pumping oil from the outlet of the second pump is filtered by a pressure oil filter and then connected in parallel to the inlet of the PTO clutch control valve and the inlet of the reversing control valve.

[0009] In some embodiments, an oil suction filter is provided in the oil suction circuit between the hydraulic pump assembly and the gearbox.

[0010] In some embodiments, the hydraulic circuit of the working attachment includes a steering hydraulic circuit, wherein the steering hydraulic circuit is provided with a steering controller as the attachment controller; The first oil circuit includes a steering return oil circuit hydraulically connected between the return port of the steering controller and the return port of the PTO clutch control valve.

[0011] In some embodiments, the hydraulic circuit of the working attachment includes a lifting hydraulic circuit, wherein the lifting hydraulic circuit is provided with a lifting multi-way valve as a controller for the attachment; The first oil circuit further includes a lifting return oil circuit hydraulically connected between the return port of the lifting multi-way valve and the return port of the PTO clutch control valve.

[0012] In some embodiments, the hydraulic circuit of the working attachment includes a chassis control hydraulic circuit, wherein the chassis control hydraulic circuit is provided with a chassis control valve as the attachment controller; The first oil circuit also includes a chassis return oil circuit hydraulically connected between the return port of the chassis control valve and the return port of the PTO clutch control valve.

[0013] In some embodiments, on / off valves are respectively provided in the lifting return oil circuit and the chassis return oil circuit.

[0014] In addition, this application also provides a power shift tractor, including the aforementioned hydraulic control system.

[0015] In the power shift tractor and its hydraulic control system of this application, a separate pump is added to provide control oil to the PTO clutch control valve and the reversing control valve, instead of connecting the return oil from other attachment hydraulic circuits to the inlet ports of the PTO clutch control valve and the reversing control valve. This avoids back pressure in the return oil circuit, which could adversely affect the attachment system. Moreover, the return oil from the first oil circuit flows into the gearbox as lubricating oil. The control oil pumped by the newly added separate pump passes through the PTO clutch control valve and the reversing control valve and returns through the return ports of their respective valves. This return oil can also be used directly as lubricating oil, thereby significantly increasing the flow rate of lubricating oil and allowing for a wider selection of models for the reversing clutch and PTO clutch used in the gearbox.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the hydraulic control system of a power shift tractor in the prior art; Figure 2 A hydraulic schematic diagram of the hydraulic control system of a power shift tractor according to a specific embodiment of this application; Figure 3 for Figure 2 A simplified diagram is provided, in which the steering controller is simplified and the steering cylinder is omitted for clarity. Figure 4 This is a hydraulic schematic diagram of the hydraulic control system of a power shift tractor according to another embodiment of this application.

[0018] Explanation of reference numerals in the attached figures Detailed Implementation

[0019] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this application.

[0020] The hydraulic control system and power shift tractor according to this application are described below with reference to the accompanying drawings.

[0021] This application aims to provide a common oil hydraulic control and lubrication system for the reversing clutch and the rear PTO clutch, which require high-flow-rate lubrication for the gearbox of a power shift tractor. To this end, this application discloses a hydraulic control system for a tractor, the hydraulic system comprising: The hydraulic circuit for the working attachment, including the attachment controller; Transmission 1, which includes a PTO clutch 11 and a reversing clutch; The control valve assembly includes a PTO clutch control valve 8 for controlling the on / off state of the PTO clutch 11 and a reversing control valve 9 for controlling the on / off state of the reversing clutch. A hydraulic pump assembly for drawing hydraulic fluid from a transmission 1 and including a first pump 2 pumping hydraulic fluid toward an inlet of an attachment controller and a second pump 3 pumping hydraulic fluid toward an inlet of a PTO clutch control valve 8 and an inlet of a directional control valve 9. The first oil circuit L0 is hydraulically connected between the return port of the attachment controller and the return port of the PTO clutch control valve 8. The second oil circuit L1 is hydraulically connected between the return port of the PTO clutch control valve 8 and the gearbox 1, so that the return oil from the attachment controller and the return oil from the PTO clutch control valve 8 flow into the gearbox 1 to be used as lubricating oil for the PTO clutch 11 and the reversing clutch.

[0022] See Figure 2 This application adds a second pump 3 to separately supply control oil to the PTO clutch control valve 8 and the reversing control valve 9. Simultaneously, it avoids connecting to... Figure 1 The return oil from the lifting multi-way valve of the lifting hydraulic system or the return oil from the steering controller of the steering hydraulic system is used as the control oil for the PTO clutch control valve 8 and the reversing control valve 9, so as to avoid excessive back pressure in the return oil circuit, which would have an adverse effect on the valves in the lifting hydraulic system or the steering hydraulic system.

[0023] Comparable, in Figure 1 In the existing technology shown, the method of using the steering return oil control valve and the PTO clutch control valve will keep the steering circuit in a high back pressure environment, which will affect the service life of the steering controller. Furthermore, the radiator will also be in a high back pressure environment, affecting its service life. As an example, Figure 2 The return oil of the first oil circuit L0 (i.e., the return oil of port T1 of the steering controller 14 shown in the figure) is only connected to the return oil port of the PTO clutch control valve 8, that is... Figure 3 As shown in port T2. In this way, the return oil from the first oil circuit L0 will not participate in the control of the PTO clutch control valve 8, but will directly participate in lubrication, thus avoiding the influence of the back pressure generated by the PTO clutch control valve 8 on the steering controller.

[0024] Meanwhile, because the newly added second pump 3 separately supplies control oil to the PTO clutch control valve 8 and the reversing control valve 9, the oil entering the P2 port of the PTO clutch control valve 8 and the P3 port of the reversing control valve 9, such as... Figure 3As shown. After passing through the control valve, the control oil returns through the return ports of the PTO clutch control valve 8 and the reversing control valve 9. The return oil of the control oil can also be used directly as lubricating oil. Combined with the return oil from the first oil circuit L0, the flow rate of the lubricating oil will be greatly increased, and the selection of the reversing clutch and PTO clutch used in the gearbox will no longer be easily restricted.

[0025] As can be seen, this application can prevent hydraulic valves such as the steering controller 14 and radiator from being impacted by back pressure, thereby improving the service life of the valves. Moreover, the lubrication flow rate is greatly improved, the clutch in the gearbox is more fully lubricated, and the clutch model selection is more flexible, thus ultimately improving and enhancing the working performance of the hydraulic control system.

[0026] Among them, the PTO clutch control valve 8 is used to control the on and off of the PTO clutch 11 to realize the on and off of the tractor's rear output shaft; the reversing control valve 9 is used to control the on and off of the reversing reverse gear clutch 12 and the reversing forward gear clutch 13 to realize the tractor's forward and reverse actions.

[0027] The return oil from the first oil circuit L0 can first be connected to the T2' port of the PTO clutch control valve 8, then through the internal oil circuit of the valve to the T2 port of the PTO clutch control valve 8, and finally through the second oil circuit L1 to the lubricating oil inlet 10 in the transmission, so that the return oil flows sequentially to each clutch through the internal channels of the transmission.

[0028] When the newly added second pump 3 supplies control oil separately, only the return oil from port T2 of the PTO clutch control valve 8 can flow into the lubricating oil inlet 10 as lubricating oil. Alternatively, the return oil from port T3 of the reversing control valve 9 can also flow into the lubricating oil inlet 10 as lubricating oil. Figure 3 In this circuit, the return oil from port T3 of the reversing control valve 9 is hydraulically connected to the second oil circuit L1, allowing the return oil from the reversing control valve 9 to flow as lubricating oil into the transmission 1. Thus, after this convergence, the lubrication flow required by the reversing clutch and PTO clutch 11 in the transmission is the sum of the return oil flows from the return ports of the steering controller 14, the PTO clutch control valve 8, and the reversing control valve 9.

[0029] See Figure 2 , Figure 3 The first oil circuit L0 is also equipped with a radiator 7 to ensure that the system oil temperature is within the allowable range. Since the first oil circuit L0 is hydraulically connected to the T2' port of the PTO clutch control valve 8, rather than hydraulically connected to the P2 port of the PTO clutch control valve 8, the back pressure of the first oil circuit L0 is extremely small, and the radiator 7 is always in a low-pressure environment, thus protecting the radiator 7.

[0030] When the newly added second pump 3 supplies control fluid independently, the pumping fluid from the outlet of the second pump 3 is filtered by the pressure oil filter 6 and then connected in parallel to the inlet of the PTO clutch control valve 8 and the inlet of the reversing control valve 9. The pressure oil filter 6 finely filters the shared fluid to ensure its cleanliness and prevent impurities from causing malfunctions in the valve ports or oil passages of the PTO clutch control valve 8 and the reversing control valve 9.

[0031] Correspondingly, a second suction filter 5 is provided in the suction oil passage between the second pump 3 and the gearbox 1 on the oil inlet side of the second pump 3. Similarly, a first suction filter 4 is provided in the suction oil passage between the first pump 2 and the gearbox 1 of the hydraulic pump assembly. In this way, the oil in the gearbox can be coarsely filtered before passing through the pumps to ensure the cleanliness of the oil, especially for the common oil in the gearbox.

[0032] Depend on Figure 2 , Figure 3 As can be seen, in this embodiment, the lubricating oil for each clutch in the transmission originates from the first pump 2 and the second pump 3. Both the first pump 2 and the second pump 3 are typically gear pumps, and the lubricating oil flow rate can be adjusted by controlling the pump speed. Of course, those skilled in the art will understand that the two pumps could theoretically also be variable displacement pumps, with variable adjustment of the flow rate into the lubricating oil passages within the transmission 1.

[0033] exist Figure 2 , Figure 3 In the illustrated embodiment, only the return oil from the steering hydraulic circuit is connected as lubricating oil to the lubricating oil inlet 10 in the gearbox. That is, the working attachment hydraulic circuit includes a steering hydraulic circuit, in which a steering controller 14 is provided as an attachment controller; wherein, the first oil circuit L0 includes a steering return oil circuit hydraulically connected between the return oil port T1 of the steering controller 14 and the return oil port T2 of the PTO clutch control valve 8.

[0034] The steering controller 14, also known as the steering control valve, is used to adjust the flow of hydraulic oil according to the mechanical signal input from the steering wheel. The steering cylinder 15 converts the hydraulic oil pressure provided by the steering controller 14 into mechanical force to drive the wheels to steer. During steering operations, the return oil flows sequentially through the return port T1 of the steering controller 14, the first oil circuit L0 shown in the diagram, the return port T2 of the PTO clutch control valve 8, and the second oil circuit L1 into the lubricating oil inlet 10 of the transmission, where it is used as lubricating oil.

[0035] Figure 2 , Figure 3The lifting hydraulic circuit is supplied with oil by a separate third pump 16, but the return oil from the lifting hydraulic circuit does not participate in clutch lubrication. However, those skilled in the art will understand that the working attachment hydraulic circuit may also include a lifting hydraulic circuit, which is equipped with a lifting multi-way valve 17 as an attachment controller, such as... Figure 4 As shown; wherein, the first oil circuit L0 may further include a lifting return oil circuit hydraulically connected between the return port of the lifting multi-way valve 17 and the return port of the PTO clutch control valve 8. That is, the return oil from the steering controller 14 and the return oil from the lifting multi-way valve 17 merge as lubricating oil, and flow into the lubricating oil inlet 10 in the gearbox through the second oil circuit L1, thereby increasing the lubrication flow.

[0036] Similarly, in other embodiments, the aforementioned hydraulic circuit for the working attachment may further include a chassis control hydraulic circuit. This chassis control hydraulic circuit includes a chassis control valve 19, which serves as the attachment controller and is supplied with oil by a fourth pump 18 alone, or by other pumps such as the first pump 2, the second pump 3, or the third pump 16. The first oil circuit L0 also includes a chassis return oil circuit hydraulically connected between the return port of the chassis control valve 19 and the return port of the PTO clutch control valve 8. In other words, the return oil from the chassis control valve 19 can also be used as lubricating oil.

[0037] See Figure 4 In this embodiment, on / off valves 20 are respectively installed in the lift return oil circuit and the chassis return oil circuit. Therefore, before the oil flows to the return port of the PTO clutch control valve 8, the flow rate of the lubricating oil flowing into the transmission 1 can be controlled by selecting whether the return oil from the lift hydraulic system and the chassis control hydraulic system is connected to the transmission lubrication oil circuit. Of course, on / off valves 20 can also be installed in the steering return oil circuit to increase the number of lubricating oil sources and more selection methods, thereby achieving more flexible and precise flow control of the transmission lubrication oil circuit.

[0038] See Figure 2 , Figure 3 In the hydraulic control system of this embodiment, the first circuit is where the common oil in the gearbox 1 is drawn out of the gearbox 1 by the third pump 16, filtered by the first suction oil filter 4, and then supplied to the lifting hydraulic circuit by the third pump 16. The return oil of the lifting hydraulic circuit goes directly back to the gearbox 1 and does not participate in clutch lubrication.

[0039] The second circuit is where the common oil is drawn from the gearbox 1 by the first pump 2, filtered by the first oil suction filter 4, and then sent by the first pump 2 to the oil inlet P1 of the steering controller 14. The steering controller 14 controls the steering cylinder 15 to achieve left and right steering of the tractor's front wheels. The return oil from the steering controller 14 enters the radiator 7 through the return oil port T1. After the oil is cooled, it flows through the T2' oil port of the PTO clutch control valve 8 into the valve, and then flows out from the T2 oil port of the PTO clutch control valve 8, providing lubrication flow to the gearbox through the second oil circuit L1.

[0040] The third circuit involves the shared oil being drawn from the transmission by the second pump 3, coarsely filtered by the second suction filter 5, and then finely filtered by the second pump 3 into the pressure filter 6. The finely filtered oil then supplies oil to the P2 port of the PTO clutch control valve 8 and the P3 port of the reversing control valve 9. The PTO clutch 11 is controlled by the PTO clutch control valve 8, and the reverse gear clutch 12 and forward gear clutch 13 are controlled by the reversing control valve 9. Oil flowing through the P2 port of the PTO clutch control valve 8 flows out through the T2 port, providing lubrication to the transmission through the second oil circuit L1. Similarly, oil flowing through the P3 port of the reversing control valve 9 flows out through the T3 port, also providing lubrication to the transmission through the second oil circuit L1. Therefore, the lubrication flow required by the reversing clutch and the PTO clutch at the rear end of the transmission is the sum of the flow rates from the return ports of the second and third circuits.

[0041] Furthermore, this application also protects a power shift tractor that includes the hydraulic control system described above. In this power shift tractor, a second pump 3 is added to provide a separate control oil source for the PTO clutch control valve 8 and the directional control valve 9, instead of using the return oil from the lifting hydraulic circuit or the steering hydraulic circuit as the control oil source for the PTO clutch control valve 8 and the directional control valve 9. This avoids the back pressure generated in the return oil circuit from affecting the steering or lifting system. This application is particularly applicable when the return oil from the steering hydraulic circuit is insufficient to support the lubrication flow required by the various clutches within the gearbox 1 when it participates in lubrication.

[0042] In the description of this application, it should be understood that 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 technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A hydraulic control system for a tractor, characterized in that, The hydraulic control system includes: The hydraulic circuit for the working attachment, including the attachment controller; The gearbox (1) is equipped with a PTO clutch (11) and a reversing clutch; The control valve assembly includes a PTO clutch control valve (8) for controlling the on / off state of the PTO clutch (11) and a reversing control valve (9) for controlling the on / off state of the reversing clutch. A hydraulic pump assembly for pumping oil from the gearbox (1) and including a first pump (2) pumping hydraulic oil toward the inlet of the attachment controller and a second pump (3) pumping hydraulic oil toward the inlet of the PTO clutch control valve (8) and the inlet of the reversing control valve (9). The first oil circuit (L0) is hydraulically connected between the return port of the attachment controller and the return port of the PTO clutch control valve (8); The second oil circuit (L1) is hydraulically connected between the return port of the PTO clutch control valve (8) and the gearbox (1), so that the return oil of the attachment controller and the return oil of the PTO clutch control valve (8) flow into the gearbox (1) to be used as lubricating oil for the PTO clutch (11) and the reversing clutch.

2. The hydraulic control system according to claim 1, characterized in that, The return oil of the reversing control valve (9) is hydraulically connected to the second oil circuit (L1), so that the return oil of the reversing control valve (9) flows into the gearbox (1) as the lubricating oil.

3. The hydraulic control system according to claim 1, characterized in that, The first oil circuit (L0) is equipped with a radiator (7).

4. The hydraulic control system according to claim 1, characterized in that, The pumped oil from the outlet of the second pump (3) is filtered by the oil pressure filter (6) and then connected in parallel to the inlet of the PTO clutch control valve (8) and the inlet of the reversing control valve (9).

5. The hydraulic control system according to claim 4, characterized in that, The oil suction line between the hydraulic pump assembly and the gearbox (1) is equipped with oil suction filters (4, 5).

6. The hydraulic control system according to any one of claims 1 to 5, characterized in that, The hydraulic circuit of the working attachment includes a steering hydraulic circuit, and the steering hydraulic circuit is provided with a steering controller (14) as the attachment controller. The first oil circuit (L0) includes a steering return oil circuit hydraulically connected between the return port of the steering controller (14) and the return port of the PTO clutch control valve (8).

7. The hydraulic control system according to claim 6, characterized in that, The hydraulic circuit of the working attachment includes a lifting hydraulic circuit, and the lifting hydraulic circuit is provided with a lifting multi-way valve (17) as the attachment controller. The first oil circuit (L0) also includes a lifting return oil circuit that is hydraulically connected between the return port of the lifting multi-way valve and the return port of the PTO clutch control valve (8).

8. The hydraulic control system according to claim 7, characterized in that, The hydraulic circuit of the working attachment includes a chassis control hydraulic circuit, and the chassis control hydraulic circuit is provided with a chassis control valve (19) as the controller of the attachment. The first oil circuit (L0) also includes a chassis return oil circuit that is hydraulically connected between the return port of the chassis control valve (19) and the return port of the PTO clutch control valve (8).

9. The hydraulic control system according to claim 8, characterized in that, The lifting return oil circuit and the chassis return oil circuit are respectively equipped with on / off valves (20).

10. A power shift tractor, characterized in that, The power shift tractor includes a hydraulic control system according to any one of claims 1 to 9.

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