Front-wheel drive system and paver

Abstract

Embodiments of the present invention provide a front-wheel drive system and a paver, wherein the front-wheel drive system includes: a load-sensing pump; a first front-wheel hydraulic motor having a first high-pressure port; a second front-wheel hydraulic motor having a second high-pressure port; a multi-way valve having an inlet, a third high-pressure port, and a fourth high-pressure port, the inlet being connected to the load-sensing pump, the third high-pressure port being connected to the first high-pressure port, and the fourth high-pressure port being connected to the second high-pressure port. In the technical solution of the present invention, by providing a multi-way valve, a free-wheel valve can be cancelled, large-flow switching can be performed, and the reaction speed is fast. In addition, the high-pressure ports of the multi-way valve are respectively connected to the high-pressure ports of the two hydraulic motors, and the two hydraulic motors can be individually controlled. The front-wheel speed can be matched according to the rear-wheel vehicle speed to improve the vehicle driving ability, effectively avoiding motor slippage. By giving different currents to the multi-way valve, differential speed and steering of the motor can be achieved, reducing the driving resistance and the degree of tire wear.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of construction machinery, and more particularly, to a front-wheel drive system and a paver. Background Art

[0002] A paver is a special construction equipment used to pave base stabilized soil materials and surface asphalt mixtures for various grades of roads, municipal roads, airports, parking lots, etc. It is of great significance to the construction quality of the road surface.

[0003] In the pavers of related technologies, the front-wheel drive system adopts the form of a load-sensing pump plus a flow-dividing valve. The load-sensing variable pump is connected to the left and right front-wheel drive motors of the wheeled paver through a front-wheel drive control valve group. The front-wheel drive control valve group includes a front-drive reversing valve arranged on the oil supply circuit and connected to the load-sensing variable pump. The front-drive reversing valve is connected to the flow-dividing valve, and the flow-dividing valve is connected to a differential lock solenoid valve. In the normal working state of the front-drive system, the differential lock solenoid valve is not energized, and the high-pressure oil port sides of the left and right front-wheel drive motors are in a connected state. At this time, the hydraulic oil is freely distributed to the left and right drive motors through the flow-dividing valve. When one side of the front wheels slips, all the oil will be supplied to the slipping drive motor. At this time, the slipping drive motor rotates at high speed and idles, while the drive motor on the side with adhesion loses power, and the entire front-wheel drive system is in a failure state. To solve this problem, the differential lock solenoid valve is energized, thereby cutting off the connection between the high-pressure sides of the left and right drive motors; the oil output by the load-sensing variable pump is evenly distributed to the left and right drive motors through the flow-dividing valve; the situation where one side slips at high speed while the other side loses power is avoided; that is, the function of the differential lock is realized through the forced distribution of the hydraulic oil by the hydraulic system.

[0004] The front-wheel drive system in the above related technologies has the following problems: 1) The free-wheel valve has a constant small-flow control, and the displacement switching time is long; 2) The differential lock solenoid valve and the flow-dividing valve are used to realize the working condition switching. The slip judgment and differential lock control need to be manually controlled, and it is often too late when people are aware, resulting in the interruption of the paving process and having a greater impact on the paving road surface quality. 3) The pressure loss of the flow-dividing valve is large and the heat generation is serious. Summary of the Invention

[0005] To solve or improve at least one of the above technical problems, an object of an embodiment of the present invention is to provide a front-wheel drive system.

[0006] Another object of the embodiments of the present invention is to provide a paver having the above front-wheel drive system.

[0007] To achieve the above object, an embodiment of the first aspect of the present invention provides a front-wheel drive system, comprising: a load-sensing pump; a first front-wheel hydraulic motor having a first high-pressure port; a second front-wheel hydraulic motor having a second high-pressure port; a multi-way valve having an inlet, a third high-pressure port and a fourth high-pressure port, the inlet being connected to the load-sensing pump through a first hydraulic line, the third high-pressure port being connected to the first high-pressure port through a second hydraulic line, and the fourth high-pressure port being connected to the second high-pressure port through a third hydraulic line.

[0008] According to the embodiment of the front-wheel drive system provided by the present invention, by providing a multi-way valve, a free-wheel valve can be cancelled, large-flow switching can be performed, and the reaction speed is fast. The high-pressure ports of the multi-way valve are respectively connected to the high-pressure ports of the two hydraulic motors, and the two hydraulic motors can be individually controlled. The front-wheel speed can be matched according to the rear-wheel speed to improve the vehicle driving ability, effectively avoiding motor slippage. Different currents given to the multi-way valve can achieve the differential speed and steering of the motor, which is beneficial to reducing the driving resistance and the tire wear degree. In addition, the multi-way valve also has the advantages of small pressure loss and small heat generation.

[0009] Specifically, the front-wheel drive system includes a load-sensing pump, a first front-wheel hydraulic motor, a second front-wheel hydraulic motor and a multi-way valve. Among them, the load-sensing pump is a new type of hydraulic compensator that can simultaneously sense the system pressure and flow requirements, enabling the piston pump to respond correctly according to the changes in the flow and pressure requirements. The hydraulic motor is an actuator of the hydraulic system and has a rotatable output shaft. The hydraulic motor can convert the liquid pressure provided by the hydraulic pump into the mechanical energy (torque and speed) of the output shaft. The first front-wheel hydraulic motor is drivingly connected to the first front wheel body located at the front end of the paver, and the second front-wheel hydraulic motor is drivingly connected to the second front wheel body located at the front end of the paver. In other words, the first front-wheel hydraulic motor can drive the first front wheel body to rotate, and the second front-wheel hydraulic motor can drive the second front wheel body to rotate.

[0010] Further, the first front-wheel hydraulic motor has a first high-pressure port, and the second front-wheel hydraulic motor has a second high-pressure port. The multi-way valve has an inlet, a third high-pressure port, and a fourth high-pressure port. The inlet of the multi-way valve is connected to the load-sensing pump through a first hydraulic line. The load-sensing pump can pump the working medium in the fuel tank to the multi-way valve through the first hydraulic line. The third high-pressure port of the multi-way valve is connected to the first high-pressure port of the first front-wheel hydraulic motor through a second hydraulic line, and the fourth high-pressure port of the multi-way valve is connected to the second high-pressure port of the second front-wheel hydraulic motor through a third hydraulic line. By providing the multi-way valve, the free-wheel valve can be cancelled, large-flow switching can be performed, and the reaction speed is fast. The high-pressure ports of the multi-way valve are respectively connected to the high-pressure ports of the two hydraulic motors, enabling individual control of the two hydraulic motors. Matching the front-wheel speed according to the rear-wheel vehicle speed can improve the vehicle's driving ability, effectively avoid motor slippage, and different currents given by the multi-way valve can achieve differential speed and steering of the motor, which is beneficial to reducing the driving resistance and the degree of tire wear. In addition, the multi-way valve also has the advantages of small pressure loss and small heat generation.

[0011] It should be noted that the multi-way valve in the present invention is an electro-hydraulic proportional double multi-way valve, and it can also be a multi-way valve of other forms.

[0012] In addition, the above technical solution provided by the present invention may further have the following additional technical features:

[0013] In the above technical solution, the load-sensing pump has a suction port. The first front-wheel hydraulic motor further has a first low-pressure port, and the second front-wheel hydraulic motor further has a second low-pressure port. The front-wheel drive system further includes: a fuel tank, the fuel tank is connected to the suction port through a fourth hydraulic line, the first low-pressure port is connected to the fuel tank, and the second low-pressure port is connected to the fuel tank.

[0014] In this technical solution, the load-sensing pump has a suction port. The first front-wheel hydraulic motor further has a first low-pressure port, and the second front-wheel hydraulic motor further has a second low-pressure port. Further, the front-wheel drive system further includes a fuel tank for storing the working medium. The fuel tank is connected to the suction port of the load-sensing pump through a fourth hydraulic line. The load-sensing pump can pump the working medium in the fuel tank to the multi-way valve, and then the working medium is distributed by the multi-way valve to the first front-wheel hydraulic motor or the second front-wheel hydraulic motor.

[0015] Further, the first low-pressure port of the first front-wheel hydraulic motor is connected to the fuel tank, and the second low-pressure port of the second front-wheel hydraulic motor is connected to the fuel tank. By connecting the low-pressure port of the hydraulic motor to the fuel tank, it is beneficial to reduce the pressure value of the low-pressure port, and then the pressure difference between the high-pressure port and the low-pressure port of the hydraulic motor can be increased, which is beneficial to improving the power performance of the hydraulic motor and has a good energy-saving effect with low back pressure.

[0016] Further, the load-sensing pump includes a pump body, a load-sensing valve, and a pressure cut-off valve. The load-sensing valve is connected to the Ls port of the multi-way valve and controls the pump displacement according to the flow demand of the multi-way valve. The pressure cut-off valve can limit the maximum pressure. When the system pressure exceeds the set pressure of the cut-off valve, it reduces the pump displacement and maintains the cut-off pressure.

[0017] It should be noted that the working medium in the present invention is hydraulic oil or other media.

[0018] In the above technical solution, the multi-way valve has an oil return port, a third low-pressure port, and a fourth low-pressure port. The first front-wheel hydraulic motor has a first oil drain port, and the second front-wheel hydraulic motor has a second oil drain port. After the third low-pressure port, the fourth low-pressure port, the first oil drain port, and the second oil drain port merge, they are connected to the fuel tank through a one-way valve. The working medium flows from the third low-pressure port and the fourth low-pressure port to the first oil drain port and the second oil drain port, and then flows back to the fuel tank through the one-way valve; or, the working medium flows from the first oil drain port and the second oil drain port to the third low-pressure port and the fourth low-pressure port, and then flows back to the fuel tank through the oil return port.

[0019] In this technical solution, the multi-way valve has an oil return port, a third low-pressure port, and a fourth low-pressure port. It can be understood that the multi-way valve has at least three oil ports, at least one oil port is the first three low-pressure port, at least one oil port is the fourth low-pressure port, and at least one oil port is the oil return port. The oil return port is used to connect to the fuel tank to form a hydraulic circuit. Further, the first front-wheel hydraulic motor has a first oil drain port. The second front-wheel hydraulic motor has a second oil drain port. After the third low-pressure port, the fourth low-pressure port, the first oil drain port, and the second oil drain port merge, they are connected to the fuel tank through a one-way valve. When the paver is in a non-front-drive working condition, the working medium can sequentially pass through the oil port, the oil drain port, the one-way valve, and the fuel tank. Specifically, a part of the working medium flows from the first oil port of the multi-way valve to the first oil drain port of the first front-wheel hydraulic motor, and another part of the working medium flows from the second oil port of the multi-way valve to the second oil drain port of the second front-wheel hydraulic motor. Finally, the working medium merges and flows back to the fuel tank through the one-way valve. The one-way valve controls the required switching pressure to quickly realize the switching of the motor free wheel.

[0020] In other words, after the two low-pressure ports of the multi-way valve merge, they are respectively connected to the oil drain ports of the two hydraulic motors, and a one-way valve is used to provide a stable back pressure for the oil drain of the motor for displacement switching, and the excess oil directly returns to the fuel tank. The low-pressure ports of the multi-way valve can adjust the housing pressure as needed, which is beneficial to reducing the back-pressure energy consumption.

[0021] Furthermore, the front-wheel drive system has a non-front-wheel drive condition and a front-wheel drive condition, that is, the front wheels can switch between the driving wheels and the driven wheels. When the front-wheel drive system is in the non-front-wheel drive condition, the working medium flows from the third low-pressure port and the fourth low-pressure port to the first oil drain port and the second oil drain port, and then flows back to the fuel tank through the check valve. At this time, the check valve controls the required switching pressure to quickly realize the switching of the motor free wheel. When the front-wheel drive system is in the front-wheel drive condition, the working medium flows from the first oil drain port and the second oil drain port to the third low-pressure port and the fourth low-pressure port, and then returns to the fuel tank through the oil return port of the multi-way valve. Thereby, the motor housing pressure can be reduced, the backpressure energy consumption can be reduced, and the displacement switching time can be shortened.

[0022] In the above technical solution, the first high-pressure port and the second high-pressure port are connected by a throttle valve.

[0023] In this technical solution, the first high-pressure port of the first front-wheel hydraulic motor and the second high-pressure port of the second front-wheel hydraulic motor are connected by a throttle valve, which can effectively avoid motor air suction or pressure lock. The high-pressure ports of the two hydraulic motors are connected by throttling, which is beneficial to simplifying the steering control program.

[0024] In the above technical solution, the load-sensing pump includes: a pump body, the pump body is connected to the inlet through a first liquid path; a load-sensing valve, connected to the pump body, and the feedback port of the load-sensing valve is connected to the signal port of the multi-way valve; a pressure cut-off valve, connected to the pump body and the load-sensing valve.

[0025] In this technical solution, the load-sensing pump includes a pump body, a load-sensing valve and a pressure cut-off valve. The pump body is connected to the inlet through a first liquid path. The pump body can pump the working medium from the fuel tank to the multi-way valve through the first liquid path, and then the multi-way valve distributes the working medium to the two hydraulic motors. Further, the load-sensing valve is connected to the pump body. The feedback port of the load-sensing valve is connected to the signal port of the multi-way valve, that is, the Ls port, to control the pump displacement according to the flow demand of the multi-way valve. The pressure cut-off valve is connected to the pump body, and the pressure cut-off valve is connected to the load-sensing pump. The pressure cut-off valve can limit the maximum pressure. When the system pressure exceeds the set pressure of the cut-off valve, the pump displacement is reduced and the cut-off pressure is maintained.

[0026] In the above technical solution, it further includes: a fifth liquid path, having a first end and a second end; a sixth liquid path, one end of the sixth liquid path is connected to the third low-pressure port, and the other end of the sixth liquid path is connected to the first end; a seventh liquid path, one end of the seventh liquid path is connected to the fourth low-pressure port, and the other end of the seventh liquid path is connected to the first end; an eighth liquid path, one end of the eighth liquid path is connected to the first oil drain port, and the other end of the eighth liquid path is connected to the second end; a ninth liquid path, one end of the ninth liquid path is connected to the second oil drain port, and the other end of the ninth liquid path is connected to the second end.

[0027] In this technical solution, the front-wheel drive system further includes a fifth hydraulic circuit, a sixth hydraulic circuit, a seventh hydraulic circuit, an eighth hydraulic circuit, and a ninth hydraulic circuit. Specifically, the fifth hydraulic circuit has a first end and a second end. One end of the sixth hydraulic circuit is connected to the third low-pressure port of the multi-way valve, and the other end of the sixth hydraulic circuit is connected to the first end of the fifth hydraulic circuit. One end of the seventh hydraulic circuit is connected to the fourth low-pressure port of the multi-way valve, and the other end of the seventh hydraulic circuit is connected to the first end of the fifth hydraulic circuit. A part of the working medium enters the sixth hydraulic circuit and the fifth hydraulic circuit successively from the third low-pressure port of the multi-way valve, and another part of the working medium enters the seventh hydraulic circuit and the fifth hydraulic circuit successively from the fourth low-pressure port of the multi-way valve. It can be understood that the fifth hydraulic circuit is a converging hydraulic circuit.

[0028] Further, one end of the eighth hydraulic circuit is connected to the first oil drain port of the first front-wheel hydraulic motor, and the other end of the eighth hydraulic circuit is connected to the second end of the fifth hydraulic circuit. One end of the ninth hydraulic circuit is connected to the second oil drain port of the second front-wheel hydraulic motor, and the other end of the ninth hydraulic circuit is connected to the second end of the fifth hydraulic circuit. A part of the working medium enters the eighth hydraulic circuit and the fifth hydraulic circuit successively from the first oil drain port of the first front-wheel hydraulic motor, and another part of the working medium enters the ninth hydraulic circuit and the fifth hydraulic circuit successively from the second oil drain port of the second front-wheel hydraulic motor. The working medium enters the fifth hydraulic circuit from the oil drain port of the hydraulic motor and finally flows back to the fuel tank.

[0029] In the above technical solution, it further includes: a tenth hydraulic circuit, one end and the second end of the tenth hydraulic circuit are connected, the other end of the tenth hydraulic circuit is connected to the fuel tank, and a check valve is arranged in the tenth hydraulic circuit.

[0030] In this technical solution, the front-wheel drive system further includes a tenth hydraulic circuit. Specifically, one end of the tenth hydraulic circuit is connected to the second end of the fifth hydraulic circuit, and the other end of the tenth hydraulic circuit is connected to the fuel tank. The working medium flows back to the fuel tank through the tenth hydraulic circuit. It can be understood that the low-pressure port of the hydraulic motor is communicated with the fuel tank, which is beneficial to reducing the system back pressure and has good energy-saving effect. Further, a check valve is arranged in the tenth hydraulic circuit. By arranging a check valve in the tenth hydraulic circuit, the working medium flows back to the fuel tank through the check valve after converging in the fifth hydraulic circuit. The check valve controls the required switching pressure to quickly realize the switching of the motor free wheel.

[0031] In the above technical solution, it further includes: an electro-hydraulic proportional relief valve, one end of the electro-hydraulic proportional relief valve is connected to the signal port of the multi-way valve and the feedback port of the load-sensing pump, and the other end of the electro-hydraulic proportional relief valve is connected to the fuel tank.

[0032] In this technical solution, the front-wheel drive system further includes an electro-hydraulic proportional relief valve. Specifically, one end of the electro-hydraulic proportional relief valve is connected to the signal port of the multi-way valve and the feedback port of the load-sensing pump, and the other end of the electro-hydraulic proportional relief valve is connected to the fuel tank. It can be understood that the Ls circuit of the multi-way valve is connected in parallel with the electro-hydraulic proportional relief valve. The electro-hydraulic proportional relief valve is used to adjust the system pressure, and the driving force of the hydraulic motor is changed by adjusting the flow rate and flow of the working medium.

[0033] In the above technical solution, it further includes: a filter disposed in the first liquid path.

[0034] In this technical solution, the front-wheel drive system further includes a filter. Specifically, the filter is disposed in the first liquid path. By providing the filter, the working medium entering the multi-way valve from the load-sensing pump can be filtered, which is beneficial to reducing the contamination of the hydraulic system by impurities and reducing potential safety hazards.

[0035] An embodiment of the second aspect of the present invention provides a paver, including: a frame body having a relatively arranged third end and fourth end; a first wheel body rotatably disposed at the third end; a second wheel body rotatably disposed at the fourth end; the front-wheel drive system in any of the above embodiments disposed on the frame body, the first front-wheel hydraulic motor of the front-wheel drive system being in transmission connection with the first wheel body, and the second front-wheel hydraulic motor of the front-wheel drive system being in transmission connection with the second wheel body.

[0036] According to an embodiment of the paver of the present invention, the paver includes a frame body, a first wheel body, a second wheel body, and a front-wheel drive system. Among them, the frame body has a relatively arranged third end and fourth end. The first end is the front end of the frame body, that is, the front end of the paver; the second end is the rear end of the frame body, that is, the rear end of the paver. The first wheel body is rotatably disposed at the third end, that is, the first wheel body can rotate relative to the frame body; the second wheel body is rotatably disposed at the fourth end, that is, the second wheel body can rotate relative to the frame body.

[0037] Further, the front-wheel drive system is disposed on the frame body. Specifically, the first front-wheel hydraulic motor of the front-wheel drive system is in transmission connection with the first wheel body, that is, the first front-wheel hydraulic motor can drive the first wheel body to rotate; the second front-wheel hydraulic motor of the front-wheel drive system is in transmission connection with the second wheel body, that is, the second front-wheel hydraulic motor can drive the second wheel body to rotate.

[0038] Among them, since the paver includes any of the front-wheel drive systems in the first aspect above, it has the beneficial effects of any of the above embodiments, which will not be elaborated here.

[0039] The additional aspects and advantages of the embodiments of the present invention will become apparent in the following description section, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The first schematic diagram of the front-wheel drive system according to an embodiment of the present invention is shown;

[0041] Figure 2 The second schematic diagram of the front-wheel drive system according to an embodiment of the present invention is shown;

[0042] Figure 3Shows a schematic diagram of a paver according to an embodiment of the present invention.

[0043] Among them, Figures 1 to 3 The corresponding relationship between the reference numerals and the component names in the figure is as follows:

[0044] 100: Front-wheel drive system; 110: Load-sensitive pump; 111: Suction port; 112: Pump body; 113: Load-sensitive valve; 114: Pressure cut-off valve; 120: First front-wheel hydraulic motor; 121: First high-pressure port; 122: First drain port; 123: First low-pressure port; 130: Second front-wheel hydraulic motor; 131: Second high-pressure port; 132: Second drain port; 133: Second low-pressure port; 140: Multi-way valve; 141: Third high-pressure port; 142: Fourth high-pressure port; 143: Third low-pressure port; 144: Fourth low-pressure port; 145: Inlet; 146: Return port; 150: Fuel tank; 161: Check valve; 162: Electro-hydraulic proportional relief valve; 163: Filter; 164: Throttle valve; 170: First hydraulic circuit; 171: Second hydraulic circuit; 172: Third hydraulic circuit; 173: Fourth hydraulic circuit; 174: Fifth hydraulic circuit; 1741: First end; 1742: Second end; 175: Sixth hydraulic circuit; 176: Seventh hydraulic circuit; 177: Eighth hydraulic circuit; 178: Ninth hydraulic circuit; 179: Tenth hydraulic circuit; 200: Paver; 210: Frame; 211: Third end; 212: Fourth end; 220: First wheel body; 230: Second wheel body. Detailed implementation manners

[0045] In order to more clearly understand the above objects, features and advantages of the embodiments of the present invention, the embodiments of the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0046] In the following description, many specific details are set forth in order to fully understand the present invention. However, the embodiments of the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the limitations of the specific embodiments disclosed below.

[0047] The following refers to Figures 1 to 3 Describe the front-wheel drive system 100 and the paver 200 provided according to some embodiments of the present invention. It should be noted that the front-wheel drive system 100 of the present invention can be applied to various working machines such as dump trucks and mixer trucks. Hereinafter, taking the application to a paver as an example, the front-wheel drive system 100 and the paver 200 of the present invention will be introduced exemplarily.

[0048] Embodiment 1

[0049] As Figure 1 AndFigure 2 As shown in Figure 2 , a front-wheel drive system 100 provided by an embodiment of the present invention includes a load-sensing pump 110, a first front-wheel hydraulic motor 120, a second front-wheel hydraulic motor 130, and a multi-way valve 140. Among them, the load-sensing pump 110 is a new type of hydraulic compensator that can simultaneously sense the requirements of system pressure and flow rate, enabling the piston pump to respond correctly according to the changes in flow rate and pressure requirements. A hydraulic motor is an actuator in a hydraulic system and has a rotatable output shaft. The hydraulic motor can convert the liquid pressure provided by the hydraulic pump into mechanical energy (torque and rotational speed) of the output shaft. The first front-wheel hydraulic motor 120 is drivingly connected to the first wheel body 220 located at the front end in the paver 200, and the second front-wheel hydraulic motor 130 is drivingly connected to the second wheel body 230 located at the front end in the paver 200. In other words, the first front-wheel hydraulic motor 120 can drive the first wheel body 220 to rotate, and the second front-wheel hydraulic motor 130 can drive the second wheel body 230 to rotate.

[0050] Further, the first front-wheel hydraulic motor 120 has a first high-pressure port 121, and the second front-wheel hydraulic motor 130 has a second high-pressure port 131. The multi-way valve 140 has an inlet 145, a third high-pressure port 141, and a fourth high-pressure port 142. The inlet 145 of the multi-way valve 140 is connected to the load-sensing pump 110 through a first hydraulic line 170, and the load-sensing pump 110 can pump the working medium in the fuel tank 150 to the multi-way valve 140 through the first hydraulic line 170. The third high-pressure port 141 of the multi-way valve 140 is connected to the first high-pressure port 121 of the first front-wheel hydraulic motor 120 through a second hydraulic line 171, and the fourth high-pressure port 142 of the multi-way valve 140 is connected to the second high-pressure port 131 of the second front-wheel hydraulic motor 130 through a third hydraulic line 172. By providing the multi-way valve 140, the free-wheel valve can be cancelled, large-flow switching can be performed, and the reaction speed is fast. In addition, the high-pressure ports of the multi-way valve 140 are respectively connected to the high-pressure ports of the two hydraulic motors, enabling individual control of the two hydraulic motors, matching the front-wheel speed according to the rear-wheel vehicle speed to improve the vehicle driving ability, effectively avoiding motor slip, and different currents given to the multi-way valve 140 can achieve differential speed and steering of the motor, which is beneficial to reducing the driving resistance and the degree of tire wear. In addition, the multi-way valve 140 also has the advantages of small pressure loss and small heat generation.

[0051] It should be noted that the multi-way valve 140 in the present invention is an electro-hydraulic proportional dual multi-way valve 140, and can also be other forms of multi-way valve 140.

[0052] In another embodiment, the first high-pressure port 121 of the first front-wheel hydraulic motor 120 is connected to the second high-pressure port 131 of the second front-wheel hydraulic motor 130 through a throttle valve 164, which can effectively avoid motor air suction or pressure buildup. The throttling connection of the high-pressure ports of the two hydraulic motors is beneficial to simplifying the steering control program.

[0053] Embodiment 2

[0054] As Figure 1 and Figure 2 shown, the front-wheel drive system 100 further includes an electro-hydraulic proportional relief valve 162. Specifically, one end of the electro-hydraulic proportional relief valve 162 is connected to the signal port of the multi-way valve 140 and the feedback port of the load-sensing pump 110, and the other end of the electro-hydraulic proportional relief valve 162 is connected to the fuel tank 150. It can be understood that the Ls circuit of the multi-way valve 140 is connected in parallel with the electro-hydraulic proportional relief valve 162, and the electro-hydraulic proportional relief valve 162 is used to adjust the system pressure, and the driving force of the hydraulic motor is changed by adjusting the flow rate and flow of the working medium.

[0055] In another embodiment, the front-wheel drive system 100 further includes a filter 163. Specifically, the filter 163 is provided in the first hydraulic circuit 170. By providing the filter 163, the working medium entering the multi-way valve 140 from the load-sensing pump 110 can be filtered, which is beneficial to reducing the pollution of the hydraulic system by impurities and reducing potential safety hazards.

[0056] Embodiment 3

[0057] As Figure 1 and Figure 2 shown, the load-sensing pump 110 has a suction port 111, the first front-wheel hydraulic motor 120 further has a first low-pressure port 123, and the second front-wheel hydraulic motor 130 further has a second low-pressure port 133. Further, the front-wheel drive system 100 further includes a fuel tank 150 for storing the working medium. The fuel tank 150 is connected to the load-sensing pump 110 through a fourth hydraulic circuit 173, and the load-sensing pump 110 can pump the working medium in the fuel tank 150 to the multi-way valve 140, and then the working medium is distributed by the multi-way valve 140 to the first front-wheel hydraulic motor 120 or the second front-wheel hydraulic motor 130.

[0058] Further, the first low-pressure port 123 of the first front-wheel hydraulic motor 120 is connected to the fuel tank 150, and the second low-pressure port 133 of the second front-wheel hydraulic motor 130 is connected to the fuel tank 150. By connecting the low-pressure port of the hydraulic motor to the fuel tank 150, it is beneficial to reduce the pressure value of the low-pressure port, and then the pressure difference between the high-pressure port and the low-pressure port of the hydraulic motor can be increased, which is beneficial to improving the dynamic performance of the hydraulic motor and has good energy-saving effect with low back pressure.

[0059] Further, the load-sensing pump 110 includes a pump body 112, a load-sensing valve 113, and a pressure cut-off valve 114. The pump body 112 is connected to the inlet 145 through a first hydraulic line 170. The pump body 112 can pump the working medium from the fuel tank 150 to the multi-way valve 140 through the first hydraulic line 170. Then, the multi-way valve 140 distributes the working medium to two hydraulic motors. The load-sensing valve 113 is connected to the pump body 112, and the feedback port of the load-sensing valve 113 is connected to the signal port of the multi-way valve 140 to control the pump displacement according to the flow demand of the multi-way valve 140. The pressure cut-off valve 114 is connected to the pump body 112 and is also connected to the load-sensing valve 113. The pressure cut-off valve can limit the maximum pressure. When the system pressure exceeds the set pressure of the cut-off valve, it reduces the pump displacement and maintains the cut-off pressure. At the same time, by controlling the front drive speed through the pump body 112, the pressure cut-off valve 114, and the multi-way valve 140, the requirements for the front drive multi-way valve 140 and the motor accuracy can be reduced, and the low-speed stability of the system can be improved.

[0060] It should be noted that the working medium in the present invention is hydraulic oil or other media.

[0061] Embodiment 4

[0062] As Figure 1 and Figure 2 shown, the multi-way valve 140 has an oil return port 146, a third low-pressure port 143, and a fourth low-pressure port 144. It can be understood that the multi-way valve 140 has at least three oil ports, at least one oil port is the third low-pressure port 143, at least one oil port is the fourth low-pressure port 144, and at least one oil port is the oil return port 146. The oil return port 146 is used to connect to the fuel tank 150 to form a hydraulic circuit, and the low-pressure ports on the multi-way valve 140 are used to connect to the drain ports of the hydraulic motors. Further, the first front-wheel hydraulic motor 120 has a first drain port 122, and the third low-pressure port 143 of the multi-way valve 140 is connected to the first drain port 122 of the first front-wheel hydraulic motor 120. The second front-wheel hydraulic motor 130 has a second drain port 132, and the fourth low-pressure port 144 of the multi-way valve 140 is connected to the second drain port 132 of the second front-wheel hydraulic motor 130. When the paver 200 is in a non-front-drive working condition, the working medium can sequentially pass through the oil port, the drain port, the check valve 161, and the fuel tank 150. Specifically, a part of the working medium flows from the third low-pressure port 143 of the multi-way valve 140 to the first drain port 122 of the first front-wheel hydraulic motor 120, and another part of the working medium flows from the fourth low-pressure port 144 of the multi-way valve 140 to the second drain port 132 of the second front-wheel hydraulic motor 130. Finally, after the working media converge, they flow back to the fuel tank 150 through the check valve 161. The check valve 161 controls the required switching pressure to quickly realize the switching of the motor free wheel.

[0063] In other words, after the two low-pressure ports of the multi-way valve 140 merge, they are respectively connected to the oil drain ports of the two hydraulic motors, and a check valve 161 is used to provide a stable back pressure for the oil drain of the motors for displacement switching. The excess oil directly returns to the fuel tank 150. The low-pressure port of the multi-way valve 140 can adjust the housing pressure as required, which is beneficial to reducing the back pressure energy consumption.

[0064] As Figure 1 shown, the front-wheel drive system 100 has a non-front-wheel drive condition and a front-wheel drive condition, that is, the front wheels can be switched between the driving wheels and the driven wheels. When the front-wheel drive system 100 is in the non-front-wheel drive condition, the working medium flows from the third low-pressure port 143 and the fourth low-pressure port 144 to the first oil drain port 122 and the second oil drain port 132, and then flows back to the fuel tank 150 through the check valve 161. At this time, the check valve 161 controls the required switching pressure to quickly realize the switching of the motor free wheel. When the front-wheel drive system 100 is in the front-wheel drive condition, the working medium flows from the first oil drain port 122 and the second oil drain port 132 to the third low-pressure port 143 and the fourth low-pressure port 144, and then returns to the fuel tank 150 through the oil return port 146 of the multi-way valve 140. It can be seen that compared with the prior art that continuously provides a fixed motor housing pressure, the back pressure is high, the system generates heat, and the displacement switching time is long. The present invention can adjust the motor housing pressure as required and reduce the back pressure energy consumption.

[0065] Embodiment Five

[0066] As Figure 1 and Figure 2 shown, the front-wheel drive system 100 further includes a fifth liquid path 174, a sixth liquid path 175, a seventh liquid path 176, an eighth liquid path 177, and a ninth liquid path 178. Specifically, the fifth liquid path 174 has a first end 1741 and a second end 1742. One end of the sixth liquid path 175 is connected to the third low-pressure port 143 of the multi-way valve 140, and the other end of the sixth liquid path 175 is connected to the first end 1741 of the fifth liquid path 174. One end of the seventh liquid path 176 is connected to the fourth low-pressure port 144 of the multi-way valve 140, and the other end of the seventh liquid path 176 is connected to the first end 1741 of the fifth liquid path 174. A part of the working medium enters the sixth liquid path 175 and the fifth liquid path 174 from the third low-pressure port 143 of the multi-way valve 140 in sequence, and another part of the working medium enters the seventh liquid path 176 and the fifth liquid path 174 from the fourth low-pressure port 144 of the multi-way valve 140 in sequence. It can be understood that the fifth liquid path 174 is a converging liquid path.

[0067] Further, one end of the eighth hydraulic line 177 is connected to the first oil drain port 122 of the first front-wheel hydraulic motor 120, and the other end of the eighth hydraulic line 177 is connected to the second end 1742 of the fifth hydraulic line 174. One end of the ninth hydraulic line 178 is connected to the second oil drain port 132 of the second front-wheel hydraulic motor 130, and the other end of the ninth hydraulic line 178 is connected to the second end 1742 of the fifth hydraulic line 174. A part of the working medium enters the eighth hydraulic line 177 and the fifth hydraulic line 174 successively from the first oil drain port 122 of the first front-wheel hydraulic motor 120, and another part of the working medium enters the ninth hydraulic line 178 and the fifth hydraulic line 174 successively from the second oil drain port 132 of the second front-wheel hydraulic motor 130. The working medium enters the fifth hydraulic line 174 from the oil drain port of the hydraulic motor and finally flows back to the fuel tank 150.

[0068] Further, the front-wheel drive system 100 further includes a tenth hydraulic line 179. Specifically, one end of the tenth hydraulic line 179 is connected to the second end 1742 of the fifth hydraulic line 174, and the other end of the tenth hydraulic line 179 is connected to the fuel tank 150, and the working medium flows back to the fuel tank 150 through the tenth hydraulic line 179.

[0069] Further, a check valve 161 is provided on the tenth hydraulic line 179. By providing the check valve 161 on the tenth hydraulic line 179, the working medium flows back to the fuel tank 150 through the check valve 161 after converging in the fifth hydraulic line 174, and the check valve 161 controls the required switching pressure to quickly realize the switching of the motor free wheel.

[0070] Embodiment Six

[0071] As Figure 3 shown, a paver 200 provided by an embodiment of the present invention includes a frame 210, a first wheel body 220, a second wheel body 230, and a front-wheel drive system 100. Among them, the frame 210 has a third end 211 and a fourth end 212 arranged oppositely, the first end 1741 is the front end of the frame 210, that is, the front end of the paver 200; the second end 1742 is the rear end of the frame 210, that is, the rear end of the paver 200. The first wheel body 220 is rotatably provided at the third end 211, that is, the first wheel body 220 can rotate relative to the frame 210; the second wheel body 230 is rotatably provided at the fourth end 212, that is, the second wheel body 230 can rotate relative to the frame 210.

[0072] Further, the front-wheel drive system 100 is provided on the frame 210. Specifically, the first front-wheel hydraulic motor 120 of the front-wheel drive system 100 is in transmission connection with the first wheel body 220, that is, the first front-wheel hydraulic motor 120 can drive the first wheel body 220 to rotate; the second front-wheel hydraulic motor 130 of the front-wheel drive system 100 is in transmission connection with the second wheel body 230, that is, the second front-wheel hydraulic motor 130 can drive the second wheel body 230 to rotate.

[0073] According to an embodiment of the front-wheel drive system and the paver of the present invention, by providing a multi-way valve, large-flow switching can be performed, and the response speed is fast. In addition, the high-pressure ports of the multi-way valve are respectively connected to the high-pressure ports of two hydraulic motors, enabling independent control of the two hydraulic motors. Matching the front-wheel speed according to the rear-wheel vehicle speed can improve the vehicle driving ability, effectively avoid motor slippage, and different currents given to the multi-way valve can achieve differential speed and steering of the motor, which is beneficial to reducing the driving resistance and the degree of tire wear. In addition, the multi-way valve also has the advantages of small pressure loss and small heat generation.

[0074] In the present invention, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected to", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be construed as a limitation to the present invention.

[0076] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0077] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A front-wheel drive system (100), characterized in that, comprising: a load-sensing pump (110); a first front-wheel hydraulic motor (120), the first front-wheel hydraulic motor (120) having a first high-pressure port (121); a second front-wheel hydraulic motor (130), the second front-wheel hydraulic motor (130) having a second high-pressure port (131); a multi-way valve (140), the multi-way valve (140) having an inlet (145), a third high-pressure port (141) and a fourth high-pressure port (142), the inlet (145) being connected to the load-sensing pump (110) through a first hydraulic line (170), the third high-pressure port (141) being connected to the first high-pressure port (121) through a second hydraulic line (171), and the fourth high-pressure port (142) being connected to the second high-pressure port (131) through a third hydraulic line (172); the load-sensing pump (110) having a suction port (111), the first front-wheel hydraulic motor (120) further having a first low-pressure port (123), the second front-wheel hydraulic motor (130) further having a second low-pressure port (133), and the front-wheel drive system (100) further comprising: a fuel tank (150), the fuel tank (150) being connected to the suction port (111) through a fourth hydraulic line (173), the first low-pressure port (123) being connected to the fuel tank (150), and the second low-pressure port being connected to the fuel tank (150); the multi-way valve (140) having a return port (146), a third low-pressure port (143) and a fourth low-pressure port (144), the first front-wheel hydraulic motor (120) having a first drain port (122), the second front-wheel hydraulic motor (130) having a second drain port (132), the third low-pressure port (143), the fourth low-pressure port (144), the first drain port (122) and the second drain port (132) merging and then being connected to the fuel tank (150) through a check valve (161), and the return port (146) being used to connect to the fuel tank (150), wherein, when the front-wheel drive system (100) is in a non-front-wheel drive working condition, the working medium flows from the third low-pressure port (143) and the fourth low-pressure port (144) to the first drain port (122) and the second drain port (132), and then flows back to the fuel tank (150) through the check valve (161); or, when the front-wheel drive system (100) is in a front-wheel drive working condition, the working medium flows from the first drain port (122) and the second drain port (132) to the third low-pressure port (143) and the fourth low-pressure port (144), and then flows back to the fuel tank (150) through the return port (146); the multi-way valve (140) is an electro-hydraulic proportional double multi-way valve.

2. The front-wheel drive system (100) according to claim 1, characterized in that, the first high-pressure port (121) is connected to the second high-pressure port (131) through a throttle valve (164).

3. The front-wheel drive system (100) according to claim 1, characterized in that, The load-sensing pump (110) includes: A pump body (112) connected to the inlet (145) through the first liquid path (170); A load-sensing valve (113) connected to the pump body (112), and the feedback port of the load-sensing valve (113) is connected to the signal port of the multi-way valve (140); A pressure cut-off valve (114) connected to the pump body (112) and the load-sensing valve (113).

4. The front-wheel drive system (100) according to claim 1, characterized in that, it further includes: A fifth liquid path (174) having a first end (1741) and a second end (1742); A sixth liquid path (175), one end of the sixth liquid path (175) is connected to the third low-pressure port (143), and the other end of the sixth liquid path (175) is connected to the first end (1741); A seventh liquid path (176), one end of the seventh liquid path (176) is connected to the fourth low-pressure port (144), and the other end of the seventh liquid path (176) is connected to the first end (1741); An eighth liquid path (177), one end of the eighth liquid path (177) is connected to the first oil drain port (122), and the other end of the eighth liquid path (177) is connected to the second end (1742); A ninth liquid path (178), one end of the ninth liquid path (178) is connected to the second oil drain port (132), and the other end of the ninth liquid path (178) is connected to the second end (1742).

5. The front-wheel drive system (100) according to claim 4, characterized in that, it further includes: A tenth liquid path (179), one end of the tenth liquid path (179) is connected to the second end (1742), the other end of the tenth liquid path (179) is connected to the fuel tank (150), and a check valve (161) is provided in the tenth liquid path (179).

6. The front-wheel drive system (100) according to claim 1, characterized in that, it further includes: An electro-hydraulic proportional relief valve (162), one end of the electro-hydraulic proportional relief valve (162) is connected to the signal port of the multi-way valve (140) and the feedback port of the load-sensing pump (110), and the other end of the electro-hydraulic proportional relief valve (162) is connected to the fuel tank (150).

7. The front-wheel drive system (100) according to any one of claims 1 to 6, characterized in that, it further includes: A filter (163) provided in the first liquid path (170).

8. A paver (200), characterized in that, it includes: A frame body (210) having a third end (211) and a fourth end (212) arranged oppositely; A first wheel body (220) rotatably provided at the third end (211); A second wheel body (230) rotatably provided at the fourth end (212); The front-wheel drive system (100) according to any one of claims 1 to 6, which is provided on the frame body (210), wherein the first front-wheel hydraulic motor (120) of the front-wheel drive system (100) is in driving connection with the first wheel body (220), and the second front-wheel hydraulic motor (130) of the front-wheel drive system (100) is in driving connection with the second wheel body (230).

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