Power takeoff hydraulic system and control method

Abstract

The invention relates to the technical field of power takeoffs, in particular to a power takeoff hydraulic system and a control method.The power takeoff hydraulic system comprises an oil pump assembly communicating with the interior of a power takeoff, a heat exchange unit arranged on the power takeoff, an operation oil way communicating with a gear engaging and disengaging unit and an electromagnetic reversing valve used for adjusting the oil supply state of the operation oil way; by optimizing an oil pump pipeline, on one hand, oil in the power takeoff is cooled through the heat exchange unit, the actual use requirement is met, and the service life of equipment is prolonged; and on the other hand, the oil supply state of the operation oil way is adjusted through the electromagnetic reversing valve, so that gear engaging and gear disengaging operation can be achieved, meanwhile, oil circulation can be achieved, the requirement for internal lubrication of the power takeoff is met, the service life of the power takeoff is further prolonged, and the actual operation requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of power take-offs, and in particular to a power take-off hydraulic system and a control method. Background Art

[0002] As society develops, the number of specialized vehicles continues to increase, and the use of power take-offs (PTOs) has become more widespread. As a key component that extracts mechanical power from the vehicle's power source and transmits it to various auxiliary equipment, PTOs play an indispensable role in specialized vehicles such as fire trucks, sanitation trucks, and construction vehicles.

[0003] According to regulations, the oil temperature of the power output device should not be greater than 100°C. Therefore, the power take-off as a power output device needs to maintain its oil temperature not too high; although the Chinese invention patent with publication number CN115158010B provides a special vehicle chassis and special vehicle, by cooling a power take-off port of the power take-off, thereby achieving engine cooling; but this method cannot effectively reduce the temperature of the power take-off; although the Chinese invention patent application with publication number CN117307521A provides a fire truck power take-off cooling fan control system and method, by using a temperature sensor to collect the temperature of the lubricating oil, so as to start the cooling fan time to cool the power take-off when the temperature is greater than a threshold, but the existing method only provides a power take-off cooling control strategy, and does not specifically disclose the oil circuit layout design for cooling in the power take-off, which cannot meet actual usage needs. Summary of the Invention

[0004] The purpose of the present invention is to provide a hydraulic system and control method for a power take-off, which can effectively cool the power take-off by optimizing the oil circuit design of the power take-off, thereby solving the technical problem that the current power take-off cooling oil circuit does not meet the usage requirements.

[0005] The present invention solves the above-mentioned technical problems by: A power take-off hydraulic system includes an oil pump assembly connected to the interior of the power take-off, a heat exchange unit provided on the power take-off, an operating oil circuit connected to a gear shifting unit, and an electromagnetic reversing valve for adjusting the oil supply state of the operating oil circuit; The electromagnetic reversing valve is connected to the operating oil circuit, and the operating oil circuit is also connected to the inside of the power take-off. The oil pump assembly is connected to the operating oil circuit through the oil pump pipeline. The heat exchange unit is connected to the oil pump pipeline to cool the oil in the power take-off.

[0006] It is further defined that the oil pump pipeline includes an oil pipe assembly, a first oil inlet pipe, a second oil inlet pipe, and a third oil inlet pipe; the oil pipe assembly, the first oil inlet pipe, and the second oil inlet pipe are connected in sequence, the heat exchange unit is connected between the second oil inlet pipe and the third oil inlet pipe, and the third oil inlet pipe is connected to the gear shifting unit through an operating oil circuit; The power take-off is provided with a main safety valve, a first oil inlet pressure relief pipe and a second oil inlet pressure relief pipe. The main safety valve is connected to the oil pipe assembly through the first oil inlet pressure relief pipe, and the main safety valve is connected to the inside of the power take-off through the second oil inlet pressure relief pipe.

[0007] It is further defined that the power take-off hydraulic system further includes a filter, the filter including a filter element and a filter bypass valve; The filter element is arranged in the housing of the power take-off, and a filter cavity is formed between the filter element and the housing of the power take-off. The outlet of the first oil inlet pipe is connected to the filter cavity, and the inlet of the second oil inlet pipe is connected to the interior of the filter element. The filter bypass valve is arranged on the filter element, and one end of the filter bypass valve is connected to the filter cavity, and the other end of the filter bypass valve is connected to the interior of the filter element.

[0008] It is further defined that the heat exchange unit includes a cooler connected to the power take-off and a cooling bypass valve connected to the cooler; The power take-off has two cooling oil circuit connection ports, each of which is provided with a connecting thread, and a sealing ring groove is provided on the outer side of the top of the cooling oil circuit connection port; the cooler is connected to the second oil inlet pipe through one cooling oil circuit connection port, and the cooler is connected to the third oil inlet pipe through another cooling oil circuit connection port; the cooling bypass valve is connected between the second oil inlet pipe and the third oil inlet pipe.

[0009] It is further defined that the shift engaging and disengaging unit includes a gear operating oil pipe, a cylinder, a piston, a piston return spring and a lubricating oil circuit; The inlet of the gear operating oil pipe is connected to the working oil circuit, one end of the piston is movably connected to the cylinder body, and a gear engagement chamber is formed between the piston and the cylinder body. The outlet of the gear operating oil pipe is connected to the gear engagement chamber, and the other end of the piston is connected to the piston return spring; the inlet of the lubricating oil circuit is connected to the working oil circuit, and the outlet of the lubricating oil circuit is connected to the interior of the power take-off for lubricating the interior of the power take-off; a throttle hole is provided on the gear operating oil pipe, and the throttle hole is connected to the interior of the power take-off.

[0010] It is further defined that the operating oil circuit includes a first operating oil pipe, a second operating oil pipe, a third operating oil pipe and a fourth operating oil pipe, and the first operating oil pipe, the second operating oil pipe, the third operating oil pipe and the fourth operating oil pipe are all connected to the electromagnetic reversing valve; The inlet of the first operating oil pipe is connected to the third oil inlet pipe, the second operating oil pipe is connected to the inlet of the gear operation oil pipe, the outlet of the third operating oil pipe is connected to the inlet of the lubricating oil circuit, the outlet of the fourth operating oil pipe is connected to the inside of the power take-off, and the second operating oil pipe is connected to the inlet of the lubricating oil circuit through the gear oil circuit bypass valve.

[0011] It is further defined that the gear-engaging oil bypass valve includes a valve body, a valve seat, a valve core and a valve body spring; The valve body is sleeved on the outside of the valve core, one end of the valve core is slidably connected to the inside of the valve body, and a valve seat is sleeved on the outside of the other end of the valve core, the valve seat is tightly connected to the valve body, one end of the valve seat cooperates with the other end of the valve core, the valve body spring is sleeved on the outside of the valve core, the valve body spring is located between the valve body and the valve core, one end of the valve body spring is connected to the valve core, and the other end of the valve body spring contacts the valve body; a pressure relief hole is opened on the valve body, the second operating oil pipe is connected to the other end of the valve seat, and the pressure relief hole is connected to the lubricating oil circuit.

[0012] It is further defined that the electromagnetic reversing valve is a two-position four-way reversing valve; When the electromagnetic reversing valve is energized, the first operating oil pipe is connected to the second operating oil pipe through the electromagnetic reversing valve; When the electromagnetic reversing valve loses power, the first operating oil pipe is connected to the third operating oil pipe through the electromagnetic reversing valve, and the second operating oil pipe is connected to the fourth operating oil pipe through the electromagnetic reversing valve.

[0013] It is further defined that the electromagnetic reversing valve is a two-position three-way reversing valve; When the electromagnetic reversing valve is energized, the first operating oil pipe is connected to the second operating oil pipe through the electromagnetic reversing valve; When the electromagnetic reversing valve loses power, the first operating oil pipe is connected to the third operating oil pipe through the electromagnetic reversing valve.

[0014] A power take-off hydraulic system control method, based on the above-mentioned power take-off hydraulic system, comprises the following steps: Power take-off gear shifting action: The electromagnetic reversing valve is energized; The oil pump assembly pumps oil through the oil pipe assembly, the first oil inlet pipe, the filter chamber, the filter element, the second oil inlet pipe, the cooler, the third oil inlet pipe, the first operating oil pipe, the solenoid reversing valve, the second operating oil pipe and the gear operation oil pipe in sequence, and flows into the gear engagement chamber, pushing the piston to move and compressing the piston return spring; Power take-off gear retention: The solenoid reversing valve remains energized and the oil pump assembly keeps pumping; When the pressure inside the second operating oil pipe exceeds the opening value of the gear-engaging oil bypass valve, the piston maintains the gear-engaging state of the power take-off under the pressure of the gear-engaging chamber. The second operating oil pipe is connected to the inlet of the lubricating oil circuit through the gear-engaging oil bypass valve to lubricate the inside of the power take-off. Power take-off disengagement action: The solenoid reversing valve loses power and the oil pump assembly keeps pumping; The piston return spring pushes the piston to move in the opposite direction. Part of the oil in the gear-engaging chamber flows into the power take-off through the gear operating oil pipe, the second operating oil pipe and the fourth operating oil pipe in sequence, and the other part flows into the power take-off through the throttle hole. Power take-off gear retention: The solenoid reversing valve remains de-energized and the oil pump assembly continues pumping; The oil pump assembly pumps oil through the oil pipe assembly, the first oil inlet pipe, the filter element, the second oil inlet pipe, the cooler, the third oil inlet pipe, the first operating oil pipe, the solenoid reversing valve, the third operating oil pipe and the lubricating oil circuit in sequence to lubricate the inside of the power take-off.

[0015] A power take-off hydraulic system control method, based on the above-mentioned power take-off hydraulic system, comprises the following steps: Power take-off gear shifting action: The electromagnetic reversing valve is energized; The oil pump assembly pumps oil through the oil pipe assembly, the first oil inlet pipe, the filter chamber, the filter element, the second oil inlet pipe, the cooler, the third oil inlet pipe, the first operating oil pipe, the solenoid reversing valve, the second operating oil pipe and the gear operation oil pipe in sequence, and flows into the gear engagement chamber, pushing the piston to move and compressing the piston return spring; Power take-off gear retention: The solenoid reversing valve remains energized and the oil pump assembly keeps pumping; When the pressure inside the second operating oil pipe exceeds the opening value of the gear-engaging oil bypass valve, the piston maintains the gear-engaging state of the power take-off under the pressure of the gear-engaging chamber. The second operating oil pipe is connected to the inlet of the lubricating oil circuit through the gear-engaging oil bypass valve to lubricate the inside of the power take-off. Power take-off disengagement action: The oil pump assembly keeps pumping, the electromagnetic reversing valve loses power, the piston return spring pushes the piston to move in the opposite direction, and the oil in the gear-engaging chamber flows into the power take-off through the throttle hole; Power take-off gear retention: The solenoid reversing valve remains de-energized and the oil pump assembly continues pumping; The oil pump assembly pumps oil through the oil pipe assembly, the first oil inlet pipe, the filter element, the second oil inlet pipe, the cooler, the third oil inlet pipe, the first operating oil pipe, the solenoid reversing valve, the third operating oil pipe and the lubricating oil circuit in sequence to lubricate the inside of the power take-off.

[0016] The beneficial effects of the present invention are: 1. The present invention optimizes the design of the oil circuit on the power take-off. On the one hand, a heat exchange unit is used to cool the oil inside the power take-off, thereby meeting actual use requirements and improving the service life of the equipment. On the other hand, an electromagnetic reversing valve is used to adjust the oil supply status of the operating oil circuit, so that it can achieve gear shifting and disengaging operations while also achieving oil circulation, thereby meeting the need for internal lubrication of the power take-off, further improving the service life of the power take-off, and meeting actual operation requirements.

[0017] 2. The present invention ensures stable and reliable cooling and lubrication of the power take-off by arranging a main safety valve, a filter bypass valve, a cooling bypass valve and a gear shift oil bypass valve, thereby improving the safety and stability of the power take-off.

[0018] 3. The electromagnetic reversing valve of the present invention uses a two-position four-way valve to achieve rapid gear shifting, effectively shortening the semi-clutch time during the gear shifting process of the power take-off, thereby extending the life of the gear shifting mechanism of the power take-off; at the same time, the electromagnetic reversing valve can also use a two-position three-way valve according to demand to reduce costs.

[0019] 4. The solution of connecting the cooler to the power take-off of the present invention can take into account both plate connection and threaded connection, and can meet the needs of different customers.

[0020] 5. Lubrication and gear shifting priority function. The cooling bypass valve ensures that when the cooler is blocked, the lubrication and gear shifting functions are prioritized. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the power take-off and its hydraulic system of the present invention; Figure 2 for Figure 1 Cross-section in the middle AA direction; Figure 3 for Figure 1 Cross-section in the middle DD direction; FIG4 is a schematic diagram of a cooling oil circuit connection port of the present invention; Figure 4a This is a cross-sectional view of the cooling oil circuit connection port. Figure 4b 4c is a schematic diagram of the threaded connection of the cooling oil circuit connection port; Figure 5 for Figure 6 Cross-section in the CC direction; Figure 6 for Figure 2 Cross-sectional view of a two-position four-way valve in the middle BB direction; Figure 7 for Figure 6 Cross-section in the middle EE direction; Figure 8 This is a structural diagram of the gear shift oil bypass valve of the present invention; Figure 9 is a schematic diagram of the working state of the electromagnetic reversing valve in Example 1, Figure 9a This is a schematic diagram of the electromagnetic reversing valve being energized. Figure 9b This is a schematic diagram of the electromagnetic reversing valve in the power-off state; Figure 10 for Figure 2 Cross-sectional view of a two-position three-way valve in the middle BB direction; Figure 11 is a schematic diagram of the working state of the electromagnetic reversing valve in Example 2, Figure 11a This is a schematic diagram of the electromagnetic reversing valve being energized. Figure 11bThis is a schematic diagram of the electromagnetic reversing valve in the power-off state.

[0022] In the figure, 100, power take-off; 110, main safety valve; 111, first oil inlet pressure relief pipe; 112, second oil inlet pressure relief pipe; 120, cooling oil circuit connection port; 200, oil pump assembly; 300, oil pump pipeline; 310, oil pipe assembly; 320, first oil inlet pipe; 330, second oil inlet pipe; 340, third oil inlet pipe; 400, gear shifting unit; 410, gear operation oil pipe; 411, throttle hole; 420, cylinder body; 430, piston; 440, piston return spring; 450, lubricating oil circuit; 460, gear shifting chamber; 500, filter; 510, filter element; 511, filter chamber; 520, filter bypass valve; 600, heat exchange unit; 610, cooler ; 611, cooling oil inlet pipeline; 612, cooling oil outlet pipeline; 621, connecting thread; 622, sealing ring groove; 630, cooling bypass valve; 700, working oil circuit; 710, first working oil pipe; 711, first working oil inlet pipe; 712, first working oil outlet pipe; 720, second working oil pipe; 721, second working oil inlet pipe; 722, second working oil outlet pipe; 730, third working oil pipe; 731, third working oil inlet pipe; 732, third working oil outlet pipe; 740, fourth working oil pipe; 750, gear shift oil circuit bypass valve; 751, valve body; 752, valve seat; 753, valve core; 754, valve body spring; 755, pressure relief hole; 800, solenoid reversing valve. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Example 1 refer to Figure 1~Figure 1 1. The present invention provides a power take-off hydraulic system, comprising an oil pump assembly 200 communicating with the interior of a power take-off 100, a heat exchange unit 600 disposed on the power take-off 100, an operating oil circuit 700 communicating with a gear shifting unit 400, and an electromagnetic reversing valve 800 for regulating the oil supply state of the operating oil circuit 700. The electromagnetic reversing valve 800 is connected to the operating oil circuit 700, which is also connected to the interior of the power take-off 100. The oil pump assembly 200 is connected to the operating oil circuit 700 via an oil pump pipeline 300. The heat exchange unit 600 is connected to the oil pump pipeline 300 for cooling the oil pump pipeline 300.

[0028] Specifically, the power for the oil pump assembly 200 is obtained from the transmission shaft or gear inside the power take-off 100. The oil suction port of the oil pump assembly 200 is connected to the interior of the power take-off 100, and is used to pump the oil inside the power take-off 100 into circulation to achieve gear shifting, lubrication and cooling. The oil is gear oil; the oil outlet of the oil pump assembly 200 is connected to the oil pump pipeline 300, and the oil pump pipeline 300 can be optionally set on the outside of the power take-off 100, or it can be opened in the shell of the power take-off 100.

[0029] For further explanation, see Figure 2 The oil pump pipeline 300 includes an oil pipe assembly 310, a first oil inlet pipe 320, a second oil inlet pipe 330 and a third oil inlet pipe 340; wherein the oil pipe assembly 310 can be optionally arranged outside the power take-off 100, and the first oil inlet pipe 320, the second oil inlet pipe 330 and the third oil inlet pipe 340 are all opened in the power take-off housing.

[0030] The oil pipe assembly 310, the first oil inlet pipe 320 and the second oil inlet pipe 330 are connected in sequence, and the heat exchange unit 600 is connected between the second oil inlet pipe 330 and the third oil inlet pipe 340, and is used to cool the gear oil input by the second oil inlet pipe 330, and then output the cooled gear oil through the third oil inlet pipe 340. The third oil inlet pipe 340 is connected to the gear shifting unit 400 through the operating oil circuit 700, so as to cool the gear oil of the power take-off 100 and thus meet the overall cooling requirements of the power take-off 100.

[0031] refer to Figure 3 In order to avoid damage to hydraulic system components caused by abnormal pressure fluctuations and ensure the safe and reliable operation of the power take-off 100, it is preferred to provide a main safety valve 110, a first oil inlet pressure relief pipe 111 and a second oil inlet pressure relief pipe 112 on the power take-off 100. The main safety valve 110 is connected to the oil pipe assembly 310 through the first oil inlet pressure relief pipe 111, and the main safety valve 110 is connected to the inside of the power take-off 100 through the second oil inlet pressure relief pipe 112; when the oil circuit at the rear end of the oil pipe assembly 310 is blocked, the oil pump assembly 200 is prevented from remaining open and causing damage to the oil pipe assembly 310 and the oil pump assembly 200. The main safety valve 110 is provided. Therefore, when the oil circuit at the rear end of the oil pipe assembly 310 is blocked, the main safety valve 110 is pushed to open, and the first oil inlet pressure relief pipe 111 and the second oil inlet pressure relief pipe 112 are connected to realize gear oil pressure relief.

[0032] For further explanation, see Figure 2 The power take-off hydraulic system also includes a filter 500, which includes a filter element 510 and a filter bypass valve 520, and is used to filter the gear oil pumped by the oil pump assembly 200, reduce blockage and wear, and ensure the service life of the power take-off.

[0033] Among them, the filter element 510 is arranged in the housing of the power take-off 100, and a filter chamber 511 is formed between the filter element 510 and the housing of the power take-off 100. The outlet of the first oil inlet pipe 320 is connected to the filter chamber 511, and the inlet of the second oil inlet pipe 330 is connected to the interior of the filter element 510. The filter bypass valve 520 is arranged on the filter element 510, one end of the filter bypass valve 520 is connected to the filter chamber 511, and the other end of the filter bypass valve 520 is connected to the interior of the filter element 510; by setting the filter bypass valve 520, the oil pressure in the filter chamber 511 is prevented from being too high when the filter element 510 is blocked, and at the same time, the normal operation of the power take-off 100 is ensured. When the oil pressure in the filter chamber 511 is too high, the filter bypass valve 520 is pushed open, so that the first oil inlet pipe 320, the filter chamber 511, the filter bypass valve 520, the interior of the filter element 510 and the second oil inlet pipe 330 are directly connected.

[0034] For further explanation, see Figure 1 and Figure 2 The heat exchange unit 600 includes a cooler 610 and a cooling bypass valve 630 , and the cooler 610 is disposed on the housing of the power take-off 100 .

[0035] 4, the power take-off 100 has two cooling oil connection ports 120, Figure 4aA connecting thread 621 is provided inside the cooling oil circuit connection port 120, and a sealing ring groove 622 is provided on the outer side of the top of the cooling oil circuit connection port 120; the cooler 610 is connected to the second oil inlet pipe 330 through one cooling oil circuit connection port 120, and the cooler 610 is connected to the third oil inlet pipe 340 through another cooling oil circuit connection port 120.

[0036] refer to Figure 4b When the cooler 610 is arranged on the power take-off 100, the cooler 610 is connected to the cooling oil circuit connection port 120 in a plate-type manner, and a sealing ring is set in the sealing ring groove 622, so that the gear oil enters the cooler 610 through the cooling oil circuit connection port 120 for heat dissipation.

[0037] refer to Figure 4c When the cooler 610 is arranged at a position far away from the oil inlet and outlet, the cooler 610 and the cooling oil circuit connection port 120 are threadedly connected using an oil pipe and a pipe joint, so that the gear oil enters the cooler 610 through the cooling oil circuit connection port 120 for heat dissipation.

[0038] In order to prevent the cooler 610 from being clogged and affecting the lubrication of the power take-off 100 , the cooling bypass valve 630 is preferably connected between the second oil inlet pipe 330 and the third oil inlet pipe 340 .

[0039] Specifically, such as Figure 2 As shown, the second oil inlet pipe 330 is connected to the cooler 610 through the cooling oil inlet pipe 611, and the third oil inlet pipe 340 is connected to the cooler 610 through the cooling oil outlet pipe 612. The end of the second oil inlet pipe 330 and the end of the third oil inlet pipe 340 are connected through a cooling bypass valve 630, so that after the cooler 610 is blocked, the high-pressure gear oil pushes open the cooling bypass valve 630, so that the second oil inlet pipe 330 and the third oil inlet pipe 340 are directly connected to ensure the normal operation of lubrication and shifting / shifting of the power take-off 100.

[0040] For further explanation, see Figure 5 The gear shifting unit 400 includes a gear operating oil pipe 410, a cylinder 420, a piston 430, a piston return spring 440 and a lubricating oil circuit 450. The cooled gear oil is controlled by the electromagnetic reversing valve 800 to supply the gear oil for shifting and the gear oil for lubricating the inside of the power take-off 100, thereby achieving cooling and lubrication of the power take-off 100.

[0041] Specifically, the inlet of the gear operating oil pipe 410 is connected to the operating oil circuit 700, one end of the piston 430 is movably connected to the cylinder body 420, and a gear engagement chamber 460 is formed between the piston 430 and the cylinder body 420. The outlet of the gear operating oil pipe 410 is connected to the gear engagement chamber 460, and the other end of the piston 430 is connected to the piston return spring 440. A throttle hole 411 is provided on the gear operating oil pipe 410, and the throttle hole 411 is connected to the interior of the power take-off 100 for lubricating the power take-off 100.

[0042] The inlet of the lubricating oil circuit 450 is connected to the operating oil circuit 700, and the outlet of the lubricating oil circuit 450 is connected to the inside of the power take-off 100 for lubricating the inside of the power take-off 100; thereby, the electromagnetic reversing valve 800 is used to supply gear oil for gear shifting and / or lubrication of the power take-off 100 after cooling.

[0043] To further illustrate, the operating oil circuit 700 includes a first operating oil pipe 710, a second operating oil pipe 720, a third operating oil pipe 730 and a fourth operating oil pipe 740, and the first operating oil pipe 710, the second operating oil pipe 720, the third operating oil pipe 730 and the fourth operating oil pipe 740 are all connected to the electromagnetic reversing valve 800. By controlling the power supply and power loss of the electromagnetic reversing valve 800, the connection and shutoff between the first operating oil pipe 710, the second operating oil pipe 720, the third operating oil pipe 730 and the fourth operating oil pipe 740 are achieved.

[0044] Specifically, refer to Figure 2 and Figure 6 The first operating oil pipe 710 includes a first operating oil inlet pipe 711 and a first operating oil outlet pipe 712. The inlet of the first operating oil inlet pipe 711 is connected to the outlet of the third oil inlet pipe 340, and the outlet of the first operating oil inlet pipe 711 is connected to the electromagnetic reversing valve 800 through the first operating oil outlet pipe 712.

[0045] refer to Figure 5 and Figure 6 The second operating oil pipe 720 includes a second operating oil inlet pipe 721 and a second operating oil outlet pipe 722. The inlet of the second operating oil outlet pipe 722 is connected to the electromagnetic reversing valve 800 through the second operating oil inlet pipe 721, and the outlet of the second operating oil outlet pipe 722 is connected to the inlet of the gear operating oil pipe 410.

[0046] refer to Figure 6 and Figure 7 The third operating oil pipe 730 includes a third operating oil inlet pipe 731 and a third operating oil outlet pipe 732. The inlet of the third operating oil outlet pipe 732 is connected to the electromagnetic reversing valve 800 through the third operating oil inlet pipe 731, and the outlet of the third operating oil outlet pipe 732 is connected to the inlet of the lubricating oil circuit 450.

[0047] refer to Figure 7The inlet of the fourth operating oil pipe 740 is connected to the electromagnetic reversing valve 800 , and the outlet of the fourth operating oil pipe 740 is connected to the interior of the power take-off 100 .

[0048] Among them, the second operating oil outlet pipe 722 is connected to the inlet of the lubricating oil circuit 450 through the gear shift oil circuit bypass valve 750. When the pressure of the gear operating oil pipe 410 is too high, the gear shift oil circuit bypass valve 750 can be opened, and the cooled gear oil can be lubricated and cooled through the lubricating oil circuit 450 to achieve the lubrication and cooling of the power take-off 100.

[0049] Specifically, refer to Figure 8 The gear-engaging oil circuit bypass valve 750 includes a valve body 751, a valve seat 752, a valve core 753 and a valve body spring 754. One end of the valve core 753 is a cylindrical structure, and the other end of the valve core 753 is a conical structure.

[0050] The valve body 751 is sleeved on the outer side of the valve core 753 as a whole. One end of the valve core 753 is slidably connected to the inside of the valve body 751. The outer side of the other end of the valve core 753 is sleeved with a valve seat 752. The valve seat 752 and the valve body 751 can be fastened by a clearance fit or a threaded connection. One end of the valve seat 752 cooperates with the other end of the valve core 753 so that the conical structure can block one end of the valve seat 752. At this time, the valve body spring 754 is sleeved on the outer side of the valve core 753. The valve body spring 754 is located between the valve body 751 and the valve core 753. The valve body spring 75 4 is connected to the valve core 753, and the other end of the valve body spring 754 is in contact with the valve body 751. In the initial state, the valve body spring 754 is subjected to a small extrusion to form a preset pressure of the oil bypass valve 750. The valve body spring 754 pushes the valve core 753 to block one end of the valve seat 752, and the other end of the valve seat 752 is connected to the external environment. When the external environment pressure is higher than the preset pressure of the oil bypass valve 750, the valve core 753 is pushed to move along the axis of the valve body 751, and the valve body spring 754 is further squeezed. At this time, the external environment is connected to the inside of the valve body 751.

[0051] Specifically, a pressure relief hole 755 is formed on the valve body 751 , the other end of the valve seat 752 is communicated with the interior of the second operating oil outlet pipe 722 , and the pressure relief hole 755 is communicated with the lubricating oil passage 450 .

[0052] For further explanation, see Figure 6 、 Figure 7 As shown in FIG9 , the electromagnetic reversing valve 800 is a two-position four-way reversing valve.

[0053] refer to Figure 9a When the electromagnetic reversing valve 800 is energized, the first operating oil outlet pipe 712 is connected to the second operating oil inlet pipe 721 through the electromagnetic reversing valve 800.

[0054] refer to Figure 9bWhen the electromagnetic reversing valve 800 loses power, the first operating oil outlet pipe 712 is connected to the third operating oil inlet pipe 731 through the electromagnetic reversing valve 800, and the second operating oil inlet pipe 721 is connected to the fourth operating oil pipe 740 through the electromagnetic reversing valve 800.

[0055] Example 2 refer to Figure 10 11 and Example 1 are different in that, in the power take-off hydraulic system provided in this embodiment, the electromagnetic reversing valve 800 is a two-position three-way reversing valve, thereby reducing costs.

[0056] refer to Figure 11a When the electromagnetic reversing valve 800 is energized, the first operating oil outlet pipe 712 is connected to the second operating oil inlet pipe 721 through the electromagnetic reversing valve 800; refer to Figure 11b When the electromagnetic reversing valve 800 loses power, the first operating oil outlet pipe 712 is connected to the third operating oil inlet pipe 731 through the electromagnetic reversing valve 800.

[0057] Example 3 Based on the power take-off hydraulic system described in Example 1, this embodiment provides a power take-off hydraulic system control method, including the following steps: Power take-off gear shifting action: The electromagnetic reversing valve 800 is energized. At this time, the first operating oil outlet pipe 712 is connected only to the second operating oil inlet pipe 721 through the electromagnetic reversing valve 800, and the oil pump assembly 200 keeps pumping.

[0058] The oil pump assembly 200 pumps the gear oil inside the power take-off 100, and the gear oil passes through the oil pipe assembly 310, the first oil inlet pipe 320, the filter chamber 511, the filter element 510, the second oil inlet pipe 330, the cooling oil circuit connection port 120, the cooler 610, another cooling oil circuit connection port 120, the third oil inlet pipe 340, the first operating oil inlet pipe 711, the first operating oil outlet pipe 712, the solenoid reversing valve 800, the second operating oil inlet pipe 721, the second operating oil outlet pipe 722 and the gear operation oil pipe 410 in sequence, and flows into the gear shifting chamber 460, pushing the piston 430 to move and squeezing the piston return spring 440, thereby ensuring the normal operation of the power take-off gear shifting action oil circuit. At the same time, the throttle hole 411 can be used to immediately discharge the air inside the gear operation oil pipe 410 to achieve quick gear shifting.

[0059] Power take-off gear retention: After the gear shifting action is completed, the electromagnetic reversing valve 800 remains energized and the oil pump assembly 200 keeps pumping. At this time, the throttle hole 411 discharges the pumped gear oil.

[0060] When the throttle hole 411 fails to release pressure in time, the internal pressure of the second operating oil outlet pipe 722 exceeds the opening value of the gear-engaging oil circuit bypass valve 750. The piston 430 keeps the power take-off 100 in the gear state under the pressure of the gear-engaging oil circuit bypass valve 750. The second operating oil outlet pipe 722 is connected to the inlet of the lubricating oil circuit 450 through the gear-engaging oil circuit bypass valve 750. Most of the gear oil continuously pumped by the oil pump assembly 200 cools and lubricates the inside of the power take-off 100 through the lubricating oil circuit 450.

[0061] Power take-off disengagement action: The electromagnetic reversing valve 800 loses power, the first operating oil outlet pipe 712 is connected to the third operating oil inlet pipe 731 through the electromagnetic reversing valve 800, and the second operating oil inlet pipe 721 is connected to the fourth operating oil pipe 740 through the electromagnetic reversing valve 800, and the oil pump assembly 200 keeps pumping.

[0062] At this time, the piston return spring 440 pushes the piston 430 to move in the opposite direction, and most of the gear oil inside the gear engagement chamber 460 flows into the power take-off 100 through the gear operation oil pipe 410, the second operating oil outlet pipe 722, the second operating oil inlet pipe 721 and the fourth operating oil pipe 740 in sequence, and a small part of the gear oil flows into the power take-off 100 through the throttle hole 411 in sequence, thereby achieving rapid gear shifting.

[0063] Power take-off gear retention: The electromagnetic reversing valve 800 remains de-energized and the oil pump assembly 200 keeps pumping.

[0064] At this time, the oil pump assembly 200 pumps the gear oil through the oil pipe assembly 310, the first oil inlet pipe 320, the filter chamber 511, the filter element 510, the second oil inlet pipe 330, the cooler 610, the third oil inlet pipe 340, the first operating oil inlet pipe 711, the first operating oil outlet pipe 712, the solenoid reversing valve 800, the third operating oil inlet pipe 731, the third operating oil outlet pipe 732 and the lubricating oil circuit 450 in sequence to lubricate the inside of the power take-off 100, thereby ensuring the normal operation of the power take-off lubrication.

[0065] Example 4 Based on the power take-off hydraulic system described in Example 2, this embodiment provides a power take-off hydraulic system control method, including the following steps: Power take-off gear shifting action: The electromagnetic reversing valve 800 is energized. At this time, the first operating oil outlet pipe 712 is connected only to the second operating oil inlet pipe 721 through the electromagnetic reversing valve 800, and the oil pump assembly 200 keeps pumping.

[0066] The oil pump assembly 200 pumps the gear oil inside the power take-off 100, and the gear oil passes through the oil pipe assembly 310, the first oil inlet pipe 320, the filter chamber 511, the filter element 510, the second oil inlet pipe 330, the cooling oil circuit connection port 120, the cooler 610, another cooling oil circuit connection port 120, the third oil inlet pipe 340, the first operating oil inlet pipe 711, the first operating oil outlet pipe 712, the solenoid reversing valve 800, the second operating oil inlet pipe 721, the second operating oil outlet pipe 722 and the gear operation oil pipe 410 in sequence, and flows into the gear shifting chamber 460, pushing the piston 430 to move and squeezing the piston return spring 440, thereby ensuring the normal operation of the power take-off gear shifting action oil circuit. At the same time, the throttle hole 411 can be used to immediately discharge the air inside the gear operation oil pipe 410 to achieve quick gear shifting.

[0067] Power take-off gear retention: The electromagnetic reversing valve 800 remains energized, and the oil pump assembly 200 keeps pumping. At this time, the throttle hole 411 discharges the pumped gear oil.

[0068] When the throttle hole 411 fails to release pressure in time, the internal pressure of the second operating oil outlet pipe 722 exceeds the opening value of the gear-engaging oil circuit bypass valve 750. The piston 430 keeps the power take-off 100 in the gear state under the pressure of the gear-engaging oil circuit bypass valve 750. The second operating oil outlet pipe 722 is connected to the inlet of the lubricating oil circuit 450 through the gear-engaging oil circuit bypass valve 750. Most of the gear oil continuously pumped by the oil pump assembly 200 cools and lubricates the inside of the power take-off 100 through the lubricating oil circuit 450.

[0069] Power take-off disengagement action: The electromagnetic reversing valve 800 loses power, the oil pump assembly 200 keeps pumping, the second operating oil inlet pipe 721 and the second operating oil outlet pipe 722 are blocked at this time, the piston return spring 440 pushes the piston 430 to move in the opposite direction, and the gear oil inside the gear engagement chamber 460 flows into the power take-off 100 through the throttle hole 411, thereby achieving gear shifting.

[0070] Power take-off gear retention: The electromagnetic reversing valve 800 remains de-energized, the oil pump assembly 200 keeps pumping, and the first operating oil outlet pipe 712 is only connected to the third operating oil inlet pipe 731 through the electromagnetic reversing valve 800.

[0071] The oil pump assembly 200 pumps gear oil through the oil pipe assembly 310, the first oil inlet pipe 320, the filter chamber 511, the filter element 510, the second oil inlet pipe 330, the cooler 610, the third oil inlet pipe 340, the first operating oil inlet pipe 711, the first operating oil outlet pipe 712, the solenoid reversing valve 800, the third operating oil inlet pipe 731, the third operating oil outlet pipe 732 and the lubricating oil circuit 450 in sequence to lubricate the interior of the power take-off 100, thereby ensuring the normal operation of the power take-off lubrication.

[0072] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0073] In addition, it should be understood that although this specification describes the embodiments, not every embodiment contains only one independent technical solution. This description is for clarity only. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for the purpose of illustrating the technical concept of the present invention and cannot be used to limit the scope of protection of the present invention. Any changes made based on the technical solution in accordance with the technical concept proposed by the present invention fall within the scope of protection of the claims of the present invention.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power take-off hydraulic system, characterized in that: It comprises an oil pump assembly (200) in communication with the interior of the power take-off (100), a heat exchange unit (600) provided on the power take-off (100), an operating oil circuit (700) in communication with the gear engaging / disengaging unit (400), and an electromagnetic reversing valve (800) for adjusting the oil supply state of the operating oil circuit (700); The electromagnetic reversing valve (800) is connected to the operating oil circuit (700), and the operating oil circuit (700) is also connected to the inside of the power take-off (100). The oil pump assembly (200) is connected to the operating oil circuit (700) through the oil pump pipeline (300), and the heat exchange unit (600) is connected to the oil pump pipeline (300) for cooling the oil in the power take-off (100).

2. The power take-off hydraulic system according to claim 1, characterized in that: The oil pump pipeline (300) includes an oil pipe assembly (310), a first oil inlet pipe (320), a second oil inlet pipe (330), and a third oil inlet pipe (340); the oil pipe assembly (310), the first oil inlet pipe (320), and the second oil inlet pipe (330) are connected in sequence; the heat exchange unit (600) is connected between the second oil inlet pipe (330) and the third oil inlet pipe (340); and the third oil inlet pipe (340) is connected to the gear engaging / disengaging unit (400) via an operating oil circuit (700); The power take-off (100) is provided with a main safety valve (110), a first oil inlet pressure relief pipe (111), and a second oil inlet pressure relief pipe (112); the main safety valve (110) is connected to the oil pipe assembly (310) via the first oil inlet pressure relief pipe (111), and the main safety valve (110) is connected to the interior of the power take-off (100) via the second oil inlet pressure relief pipe (112).

3. The power take-off hydraulic system according to claim 2, characterized in that: The power take-off hydraulic system further comprises a filter (500), wherein the filter (500) comprises a filter element (510) and a filter bypass valve (520); The filter element (510) is arranged in the housing of the power take-off (100), and a filter chamber (511) is formed between the filter element (510) and the housing of the power take-off (100). The outlet of the first oil inlet pipe (320) is in communication with the filter chamber (511), and the inlet of the second oil inlet pipe (330) is in communication with the interior of the filter element (510). The filter bypass valve (520) is arranged on the filter element (510), and one end of the filter bypass valve (520) is in communication with the filter chamber (511), and the other end of the filter bypass valve (520) is in communication with the interior of the filter element (510).

4. The power take-off hydraulic system according to claim 3, characterized in that: The heat exchange unit (600) comprises a cooler (610) connected to the power take-off (100) and a cooling bypass valve (630) connected to the cooler (610); The power take-off (100) is provided with two cooling oil circuit connection ports (120), the cooling oil circuit connection ports (120) are provided with connection threads (621) inside, and a sealing ring groove (622) is provided on the outer side of the top of the cooling oil circuit connection port (120); the cooler (610) is connected to the second oil inlet pipe (330) through one cooling oil circuit connection port (120), and the cooler (610) is connected to the third oil inlet pipe (340) through the other cooling oil circuit connection port (120); the cooling bypass valve (630) is connected between the second oil inlet pipe (330) and the third oil inlet pipe (340).

5. The power take-off hydraulic system according to claim 4, characterized in that: The gear engaging and disengaging unit (400) comprises a gear operating oil pipe (410), a cylinder (420), a piston (430), a piston return spring (440) and a lubricating oil circuit (450); The inlet of the gear operating oil pipe (410) is connected to the working oil circuit (700), one end of the piston (430) is movably connected to the cylinder (420), and a gear engaging chamber (460) is formed between the piston (430) and the cylinder (420). The outlet of the gear operating oil pipe (410) is connected to the gear engaging chamber (460), and the other end of the piston (430) is connected to the piston return spring (440); the inlet of the lubricating oil circuit (450) is connected to the working oil circuit (700), and the outlet of the lubricating oil circuit (450) is connected to the inside of the power take-off (100) for lubricating the inside of the power take-off (100); a throttle hole (411) is provided on the gear operating oil pipe (410), and the throttle hole (411) is connected to the inside of the power take-off (100).

6. The power take-off hydraulic system according to claim 5, characterized in that: The operating oil circuit (700) comprises a first operating oil pipe (710), a second operating oil pipe (720), a third operating oil pipe (730), and a fourth operating oil pipe (740); the first operating oil pipe (710), the second operating oil pipe (720), the third operating oil pipe (730), and the fourth operating oil pipe (740) are all connected to the electromagnetic reversing valve (800); The inlet of the first operating oil pipe (710) is connected to the third oil inlet pipe (340), the second operating oil pipe (720) is connected to the inlet of the gear operating oil pipe (410), the outlet of the third operating oil pipe (730) is connected to the inlet of the lubricating oil circuit (450), the outlet of the fourth operating oil pipe (740) is connected to the inside of the power take-off (100), and the second operating oil pipe (720) is connected to the inlet of the lubricating oil circuit (450) through the gear oil circuit bypass valve (750).

7. The power take-off hydraulic system according to claim 6, characterized in that: The gear-engaging oil circuit bypass valve (750) comprises a valve body (751), a valve seat (752), a valve core (753) and a valve body spring (754); The valve body (751) is sleeved on the outside of the valve core (753), one end of the valve core (753) is slidably connected to the inside of the valve body (751), and the other end of the valve core (753) is sleeved on the outside of a valve seat (752), the valve seat (752) is tightly connected to the valve body (751), one end of the valve seat (752) is matched with the other end of the valve core (753), the valve body spring (754) is sleeved on the outside of the valve core (753), and the valve body spring (754) is sleeved on the outside of the valve core (753). A spring (754) is located between the valve body (751) and the valve core (753), one end of the valve body spring (754) is connected to the valve core (753), and the other end of the valve body spring (754) is in contact with the valve body (751); a pressure relief hole (755) is provided on the valve body (751), the second operating oil pipe (720) is connected to the other end of the valve seat (752), and the pressure relief hole (755) is connected to the lubricating oil circuit (450).

8. The power take-off hydraulic system according to claim 6, characterized in that: The electromagnetic reversing valve (800) is a two-position four-way reversing valve; When the electromagnetic reversing valve (800) is energized, the first operating oil pipe (710) is connected to the second operating oil pipe (720) through the electromagnetic reversing valve (800); When the electromagnetic reversing valve (800) loses power, the first operating oil pipe (710) is connected to the third operating oil pipe (730) through the electromagnetic reversing valve (800), and the second operating oil pipe (720) is connected to the fourth operating oil pipe (740) through the electromagnetic reversing valve (800).

9. The power take-off hydraulic system according to claim 6, characterized in that: The electromagnetic reversing valve (800) is a two-position three-way reversing valve; When the electromagnetic reversing valve (800) is energized, the first operating oil pipe (710) is connected to the second operating oil pipe (720) through the electromagnetic reversing valve (800); When the electromagnetic reversing valve (800) loses power, the first operating oil pipe (710) is connected to the third operating oil pipe (730) through the electromagnetic reversing valve (800).

10. A method for controlling a hydraulic system of a power take-off, characterized in that: The power take-off hydraulic system according to claim 8 comprises the following steps: Power take-off gear shifting action: The electromagnetic reversing valve (800) is energized; The oil pump assembly (200) pumps oil through the oil pipe assembly (310), the first oil inlet pipe (320), the filter chamber (511), the filter element (510), the second oil inlet pipe (330), the cooler (610), the third oil inlet pipe (340), the first operating oil pipe (710), the electromagnetic reversing valve (800), the second operating oil pipe (720) and the gear operation oil pipe (410) in sequence, and flows into the gear engagement chamber (460), pushing the piston (430) to move and compressing the piston return spring (440); Power take-off gear retention: The electromagnetic reversing valve (800) remains energized, and the oil pump assembly (200) remains pumping; The internal pressure of the second operating oil pipe (720) exceeds the opening value of the gear-engaging oil circuit bypass valve (750), and the piston (430) maintains the gear-engaging state of the power take-off under the pressure of the gear-engaging action chamber (460). The second operating oil pipe (720) is connected to the inlet of the lubricating oil circuit (450) through the gear-engaging oil circuit bypass valve (750), thereby lubricating the interior of the power take-off (100); Power take-off disengagement action: When the electromagnetic reversing valve (800) loses power, the oil pump assembly (200) keeps pumping; The piston return spring (440) pushes the piston (430) to move in the reverse direction, and a portion of the oil in the gear-engaging chamber (460) flows into the power take-off (100) through the gear operating oil pipe (410), the second operating oil pipe (720), and the fourth operating oil pipe (740) in sequence, while the other portion flows into the power take-off (100) through the throttle hole (411); Power take-off gear retention: The electromagnetic reversing valve (800) remains de-energized, and the oil pump assembly (200) continues pumping; The oil pump assembly (200) pumps oil sequentially through the oil pipe assembly (310), the first oil inlet pipe (320), the filter element (510), the second oil inlet pipe (330), the cooler (610), the third oil inlet pipe (340), the first operating oil pipe (710), the electromagnetic reversing valve (800), the third operating oil pipe (730) and the lubricating oil circuit (450) to lubricate the interior of the power take-off (100).

11. A method for controlling a hydraulic system of a power take-off, characterized in that: The power take-off hydraulic system according to claim 9 comprises the following steps: Power take-off gear shifting action: The electromagnetic reversing valve (800) is energized; The oil pump assembly (200) pumps oil through the oil pipe assembly (310), the first oil inlet pipe (320), the filter chamber (511), the filter element (510), the second oil inlet pipe (330), the cooler (610), the third oil inlet pipe (340), the first operating oil pipe (710), the electromagnetic reversing valve (800), the second operating oil pipe (720) and the gear operation oil pipe (410) in sequence, and flows into the gear engagement chamber (460), pushing the piston (430) to move and compressing the piston return spring (440); Power take-off gear retention: The electromagnetic reversing valve (800) remains energized, and the oil pump assembly (200) remains pumping; The internal pressure of the second operating oil pipe (720) exceeds the opening value of the gear-engaging oil circuit bypass valve (750), and the piston (430) maintains the gear-engaging state of the power take-off under the pressure of the gear-engaging action chamber (460). The second operating oil pipe (720) is connected to the inlet of the lubricating oil circuit (450) through the gear-engaging oil circuit bypass valve (750), thereby lubricating the interior of the power take-off (100); Power take-off disengagement action: The oil pump assembly (200) keeps pumping, the electromagnetic reversing valve (800) loses power, the piston return spring (440) pushes the piston (430) to move in the reverse direction, and the oil in the gear-engaging chamber (460) flows into the power take-off (100) through the throttle hole (411); Power take-off gear retention: The electromagnetic reversing valve (800) remains de-energized, and the oil pump assembly (200) continues pumping; The oil pump assembly (200) pumps oil sequentially through the oil pipe assembly (310), the first oil inlet pipe (320), the filter element (510), the second oil inlet pipe (330), the cooler (610), the third oil inlet pipe (340), the first operating oil pipe (710), the electromagnetic reversing valve (800), the third operating oil pipe (730) and the lubricating oil circuit (450) to lubricate the interior of the power take-off (100).

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