Hydraulic travel system and engineering vehicle

Abstract

The present invention relates to the field of vehicles, and in particular to a hydraulic travel system and an engineering vehicle. The hydraulic travel system includes a power assembly, a first motor group, a second motor group, a speed control valve group, and a switching valve group. The hydraulic travel system and the engineering vehicle provided by the present invention adjust the speed of the first motor group through the speed control valve group so that the first motor group can achieve different speeds of travel in a two-wheel drive state. The switching valve group is used to connect the travel pump with the second motor group, thereby enabling the engineering vehicle to climb a slope in a four-wheel drive mode. The speed control valve group and the switching valve group cooperate with each other to enable the engineering vehicle to travel in a four-wheel drive mode, a two-wheel drive low-speed mode, and a two-wheel drive high-speed mode, thereby meeting the travel requirements under different working conditions and improving the working efficiency of the engineering vehicle.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a hydraulic travel system and an engineering vehicle. Background Art

[0002] In existing engineering vehicles, the travel hydraulic system can realize switching modes between two-wheel drive and four-wheel drive. However, in the existing technology, the speed is constant in the two-wheel drive mode, resulting in low speed during no-load movement, which in turn leads to low working efficiency of the engineering vehicle.

[0003] Therefore, a hydraulic travel system is urgently needed to solve the above technical problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a hydraulic travel system that can meet the travel requirements under different working conditions and improve the working efficiency of engineering vehicles.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, a hydraulic travel system is provided, comprising:

[0007] Power assembly, including travel pump;

[0008] a first motor group and a second motor group, wherein the first motor group is used to drive two wheels of the engineering vehicle to rotate and move, and the second motor group is used to drive the other two wheels of the engineering vehicle to rotate and move, and the first motor group and the second motor group are respectively connected to the travel pump to form a circulation loop;

[0009] a speed control valve group connected to the travel pump to distribute oil to the first motor group and the second motor group, and the speed control valve group is configured to at least adjust the speed of the first motor group;

[0010] The switching valve group is used to selectively connect or disconnect the speed control valve group and the second motor group, so that the oil of the travel pump selectively enters the second motor group.

[0011] As an optimal technical solution for the above-mentioned hydraulic walking system, the power assembly also includes an oil replenishing pump, the speed control valve group includes a first control valve, a first hydraulic control valve and a second hydraulic control valve, the first hydraulic control valve and the second hydraulic control valve are both connected to the walking pump, the first motor group is selectively connected to the walking pump through the first hydraulic control valve, the second motor group is selectively connected to the walking pump through the second hydraulic control valve, the first control valve is connected to the oil replenishing pump, and the first control valve is connected to the displacement regulating valve of the first motor group to adjust the displacement of the first motor group.

[0012] As an optimal technical solution for the above-mentioned hydraulic walking system, the speed control valve group also includes a second control valve and a diverter and collector valve. The two oil outlets of the diverter and collector valve are respectively connected to the first motor group and the second motor group, and the oil inlet of the diverter and collector valve is connected to the first power oil port of the walking pump. The second control valve is respectively connected to the walking pump, the oil tank, the hydraulic control end of the first hydraulic control valve and the hydraulic control end of the second hydraulic control valve. The second control valve is used to selectively connect the hydraulic control end of the first hydraulic control valve to the walking pump or the oil tank. The second control valve is also used to selectively connect the hydraulic control end of the second hydraulic control valve to the walking pump or the oil tank.

[0013] As a preferred technical solution for the above-mentioned hydraulic travel system, the two oil outlets of the diverter and collector valve are connected through a first throttling member.

[0014] As an optimal technical solution for the above-mentioned hydraulic walking system, the speed control valve group also includes a first one-way valve, which is used to connect the oil replenishment pump and the diverter and collector valve. The first one-way valve is limited to the oil flowing from the oil replenishment pump to the diverter and collector valve.

[0015] As an optimal technical solution for the above-mentioned hydraulic walking system, the switching valve group includes a first switching valve and a second switching valve. The first switching valve is connected to the oil replenishment pump, and the first switching valve is connected to the pilot end of the second switching valve. The second switching valve is used to selectively connect or cut off the diverter and collector valve or the second hydraulic control valve with the second motor group.

[0016] As a preferred technical solution of the above hydraulic travel system, the first switching valve is connected to the oil tank via a second throttle member;

[0017] The second throttling member is connected to the oil tank via a second one-way valve, and the second one-way valve only limits the oil from the travel pump to the second throttling member.

[0018] As a preferred technical solution for the above-mentioned hydraulic walking system, the switching valve group also includes a third one-way valve, which is connected to the first switching valve. The third one-way valve is limited to allowing oil to flow from the first switching valve to the first oil port of the second motor group. The first switching valve is used to selectively connect the second oil port of the second motor group with the third one-way valve.

[0019] As a preferred technical solution of the above-mentioned hydraulic traveling system, the power assembly also includes an oil supply pump, and the hydraulic traveling system also includes a parking valve, which is used to selectively connect the brake oil port of the first motor group with the oil supply pump or the oil tank to brake or release the brake of the first motor group.

[0020] In a second aspect, an engineering vehicle is provided, comprising the hydraulic travel system described in any one of the schemes.

[0021] The present invention has at least the following beneficial effects:

[0022] The hydraulic travel system and engineering vehicle provided by the present invention adjust the speed of the first motor group through the speed control valve group to enable the first motor group to achieve different speeds of travel in the two-wheel drive state. The switching valve group is used to connect the travel pump with the second motor group, thereby enabling the engineering vehicle to climb slopes in the four-wheel drive mode. The speed control valve group and the switching valve group cooperate with each other to enable the engineering vehicle to travel in the four-wheel drive mode, the two-wheel drive low-speed mode and the two-wheel drive high-speed mode, thereby meeting the travel requirements under different working conditions and improving the working efficiency of the engineering vehicle.

[0023] In addition, existing internal combustion engine-driven engineering vehicles use axle drive, and the height of the axle-driven machine is relatively high, and some height-restricted areas cannot be entered. The present invention uses hydraulic drive to reduce the height of the whole machine, which is conducive to entering the height-restricted area for operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without any creative work.

[0025] Figure 1 A hydraulic principle diagram of a hydraulic travel system provided in an embodiment of the present invention;

[0026] Figure 2 for Figure 1 A partial enlarged view of point C in the middle;

[0027] Figure 3 for Figure 1 A partial enlarged view of point B in the middle;

[0028] Figure 4 for Figure 1 A partial enlarged view of point D in the middle;

[0029] Figure 5 for Figure 1 A partial enlarged view of point A in the middle;

[0030] Figure 6 for Figure 1 A partial enlarged view of point F in the middle.

[0031] In the picture:

[0032] 1. Power assembly; 11. Travel pump; 111. First power oil port; 112. Second power oil port; 12. Charge pump; 121. Third power oil port; 13. Pressure relief member; 2. First motor group; 21. First motor; 22. Second motor; 23. First displacement regulating valve; 24. Second displacement regulating valve; 25. Brake; 26. Brake disc; 3. Second motor group; 31. Third motor; 311. First oil port of third motor; 312. Second oil port of third motor; 32. Fourth motor; 321. First oil port of fourth motor; 322. Second oil port of fourth motor; 4. Speed control valve group; 41. First control valve; 411. First oil port of first control valve; 412. Second oil port of first control valve; 413. Third oil port of first control valve; 42. First hydraulic control valve Valve; 43. Second hydraulic control valve; 44. Second control valve; 441. First oil port of second control valve; 442. Second oil port of second control valve; 443. Third oil port of second control valve; 45. Diverter and collector valve; 46. First throttling device; 47. First one-way valve; 5. Switching valve group; 51. First switching valve; 511. First oil port of first switching valve; 512. Second oil port of first switching valve; 513. Third oil port of first switching valve; 52. Second switching valve; 521. First oil port of second switching valve; 522. Second oil port of second switching valve; 523. Third oil port of second switching valve; 524. Fourth oil port of second switching valve; 53. Second throttling device; 54. Third one-way valve; 6. Parking valve; 7. Fuel tank; 8. Pipeline filter; 9. Radiator; 10. Second one-way valve. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0034] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0035] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0037] The present invention provides a hydraulic travel system, which can adjust the speed of the motor under the premise of switching between four-wheel drive and two-wheel drive.

[0038] It should be noted that the hydraulic travel system provided by the present invention has three working modes: four-wheel drive climbing mode, two-wheel drive high-speed travel mode and two-wheel drive low-speed travel mode.

[0039] like Figure 1 and Figure 4 As shown, the hydraulic travel system includes a power assembly 1, a first motor group 2, a second motor group 3, a speed control valve group 4 and a switching valve group 5. The power assembly 1 includes a travel pump 11, wherein the travel pump 11 is connected to the first motor group 2 to form a closed loop, and the travel pump 11 is connected to the second motor group 3 to form a closed loop. The first motor group 2 is used to drive two of the wheels of the engineering vehicle to rotate and move, and the second motor group 3 is used to drive the other two wheels of the engineering vehicle to rotate and move. The first motor group 2 and the second motor group 3 are respectively connected to the travel pump 11 to form a circulation loop with the travel pump 11. The speed control valve group 4 is connected to the travel pump 11 to distribute oil to the first motor group 2 and the second motor group 3, and the speed control valve group 4 is configured to at least adjust the speed of the first motor group 2; the switching valve group 5 is used to selectively connect or cut off the speed control valve group 4 with the second motor group 3 so that the oil of the travel pump 11 selectively enters the second motor group 3.

[0040] The hydraulic walking system provided by the present invention adjusts the speed of at least the first motor group 2 through the speed control valve group 4, so that the first motor group 2 can achieve different speeds of walking in the two-wheel drive state. The switching valve group 5 is used to connect the power component 1 with the second motor group 3, so as to enable the engineering vehicle to climb the slope in the four-wheel drive mode. The speed control valve group 4 and the switching valve group 5 cooperate with each other to enable the engineering vehicle to walk in the four-wheel drive mode, the two-wheel drive low-speed mode and the two-wheel drive high-speed mode, thereby meeting the walking requirements under different working conditions and improving the working efficiency of the engineering vehicle.

[0041] Specifically, the travel pump 11 has a first power oil port 111 and a second power oil port 112, one of the first power oil port 111 and the second power oil port 112 is a high-pressure oil port, and the other is a low-pressure oil port. The travel pump 11 is connected to the first motor group 2 through the first power oil port 111 and the second power oil port 112 to form a closed loop. The first motor group 2 is used to drive two of the wheels of the engineering vehicle to rotate and move, and the second motor group 3 is used to drive the other two wheels of the engineering vehicle to rotate and move. The first motor group 2 and the second motor group 3 are respectively connected to the first power oil port 111 and the second power oil port 112 to form a circulation loop with the power assembly 1. The speed control valve group 4 is connected to the first power oil port 111 of the power assembly 1 to selectively distribute the oil to the first motor group 2 and the second motor group 3, and the speed control valve group 4 is configured to adjust the speed of the first motor group 2; the switching valve group 5 is used to selectively connect or cut off the speed control valve group 4 with the second motor group 3 so that the oil of the power assembly 1 selectively enters the second motor group 3.

[0042] Specifically, if Figure 5 As shown, the first motor group 2 includes a first motor 21, a first displacement regulating valve 23, a second displacement regulating valve 24, and a second motor 22. Both the first motor 21 and the second motor 22 are dual-displacement radial piston motors. For example, the first motor 21 is connected to the left front wheel to drive the left front wheel, and the second motor 22 is connected to the right front wheel to drive the right front wheel. The first displacement regulating valve 23 is used to adjust the displacement of the first motor 21, and the second displacement regulating valve 24 is used to adjust the displacement of the second motor 22. The speed control valve group 4 is configured to adjust the speed of the first motor group 2. Motor displacement regulation is conventional technology, so the specific structure and principles of the first and second displacement regulating valves 23 and 24 are not further described.

[0043] The first motor group 2 has a brake oil port. Correspondingly, the first motor 21 and the second motor 22 both have a brake 25 and a brake disc 26. The brake 25 has a return spring. The brake 25 is used to drive the brake disc 26 to brake or release the first motor 21 and the second motor 22, thereby achieving the purpose of braking the first motor 21 and the second motor 22.

[0044] For example, the first displacement regulating valve 23 and the second displacement regulating valve 24 are both pilot valves, and the first displacement regulating valve 23 and the second displacement regulating valve 24 both have a first oil port, a second oil port, a third oil port, a fourth oil port and a fifth oil port. Taking the first displacement regulating valve 23 being connected to the first motor 21 providing power for the left front wheel to adjust the displacement of the first motor 21 as an example, the first oil port of the first displacement regulating valve 23 is connected to the second oil port of the first hydraulic control valve 42, the second oil port of the first displacement regulating valve 23 and the third oil port of the first displacement regulating valve 23 are respectively connected to the first oil ports of the two first motors 21, the second oil ports of the first motors 21 are both connected to the fourth oil port of the first displacement regulating valve 23, the fourth oil port of the first displacement regulating valve 23 is connected to the fifth oil port of the first displacement regulating valve 23, and the fifth oil port of the first displacement regulating valve 23 is connected to the second power oil port 112 of the power assembly 1, so as to realize high-speed running of the first motor 21.

[0045] The first displacement regulating valve 23 is a two-position five-way pilot valve. When oil enters the pilot end of the first displacement regulating valve 23, the upper position of the first displacement regulating valve 23 is connected, the first oil port of the first displacement regulating valve 23 is connected to the second oil port of the first displacement regulating valve 23, the third oil port and the fourth oil port of the first displacement regulating valve 23 are connected to the fifth oil port respectively, the second oil port of the first displacement regulating valve 23 is connected to the first oil port of the first motor 21, and the third oil port of the first displacement regulating valve 23 and the fourth oil port of the first displacement regulating valve 23 are connected to the second oil port of the first motor 21 respectively, so as to realize low-speed running of the first motor 21.

[0046] The displacement regulation of the second motor 22 is the same as that of the first motor 21. The first oil port of the second displacement regulating valve 24 is connected to the second oil port of the second hydraulic control valve 43. The second oil port and the third oil port of the second displacement regulating valve 24 are respectively connected to the first oil ports of the two second motors 22. The second oil ports of the second motors 22 are both connected to the fourth oil port of the second displacement regulating valve 24. The fourth oil port of the second displacement regulating valve 24 is connected to the fifth oil port of the second displacement regulating valve 24, and the fifth oil port of the second displacement regulating valve 24 is connected to the second power oil port 112 of the power assembly 1 to enable the second motor 22 to run at high speed.

[0047] The second displacement regulating valve 24 is a two-position five-way pilot valve. When oil enters the pilot end of the second displacement regulating valve 24, the upper position of the second displacement regulating valve 24 is connected, the first oil port of the second displacement regulating valve 24 is connected to the second oil port of the second displacement regulating valve 24, the third oil port and the fourth oil port of the second displacement regulating valve 24 are connected to the fifth oil port respectively, the second oil port of the second displacement regulating valve 24 is connected to the first oil port of the second motor 22, the third oil port and the fourth oil port of the second displacement regulating valve 24 are connected to the second oil port of the second motor 22 respectively, so as to realize low-speed running of the second motor 22.

[0048] like Figure 6 As shown, the second motor group 3 includes a third motor 31 and a fourth motor 32. For example, the third motor 31 is connected to the left rear wheel, and the fourth motor 32 is connected to the right rear wheel.

[0049] It should be noted that the motor housings of the first motor 21, the second motor 22, the third motor 31, and the fourth motor 32 are all in communication with the oil tank 7. The third motor 31 and the fourth motor 32 are both fixed displacement radial piston motors.

[0050] In some other embodiments, the first motor 21, the second motor 22, the third motor 31, and the fourth motor 32 are all dual-displacement radial piston motors. In this case, the speed control valve assembly 4 is configured to simultaneously adjust the speeds of the first motor assembly 2 and the second motor assembly 3.

[0051] Of course, it is also possible that the first motor 21 and the second motor 22 are both fixed displacement radial piston motors, and the third motor 31 and the fourth motor 32 are both dual displacement radial piston motors. In this case, the speed control valve group 4 is configured to adjust the speed of the second motor group 3.

[0052] For example, in the four-wheel drive climbing mode, the first motor 21, the second motor 22, the third motor 31 and the fourth motor 32 are all drive motors, that is, all four wheels are drive wheels. At this time, the driving force is large and the climbing ability is strong. It is suitable for uneven roads and working conditions that require climbing. At this time, the vehicle's travel speed is lower than that of the vehicle in the two-wheel drive mode.

[0053] Two-wheel drive high-speed walking mode: Among the four motors, only the motor in the first motor group 2 is the driving motor, and the motor in the second motor group 3 connected to the rear wheel is the follower motor, which rotates freely according to the forward and backward movement. Under this working condition, the first motor group 2 is in small displacement mode. This walking mode is the fastest and is suitable for transfers. It improves work efficiency and can avoid the problem of shortened working time due to long transfer distances.

[0054] Two-wheel drive low-speed walking mode: Among the four motors, only the motor in the first motor group 2 is the driving motor, and the motor in the second motor group 3 connected to the rear wheel is the follower motor, which rotates freely according to the forward and backward movement. Under this working condition, the first motor group 2 is in large-displacement mode. This walking mode has a medium speed and is suitable for compound movements. At this time, you can walk while performing the gantry movement, which improves work efficiency.

[0055] In some embodiments, as Figure 2 and Figure 4As shown, the power assembly 1 also includes an oil charge pump 12, and the speed control valve group 4 includes a first control valve 41, a first hydraulic control valve 42, and a second hydraulic control valve 43. The first oil port of the first hydraulic control valve 42 and the first oil port of the second hydraulic control valve 43 are both connected to the first power oil port 111, and the second oil port of the first hydraulic control valve 42 is connected to the first motor group 2. The first motor group 2 is connected to the travel pump 11 through the first hydraulic control valve 42. The second oil port of the second hydraulic control valve 43 is connected to the second motor group 3. The second motor group 3 is connected to the travel pump 11 through the second hydraulic control valve 43. The first control valve 41 is connected to the third power oil port 121 of the power assembly 1, and the first control valve 41 is connected to the displacement regulating valve of the first motor group 2. The displacement regulating valve is used to adjust the displacement of the first motor group 2. Specifically, the first oil port of the first control valve 41 is connected to the oil port of the oil charge pump 12 (that is, the third power oil port 121). The first hydraulic control valve 42 is used to connect or disconnect the power assembly 1 with the first motor group 2, and the second hydraulic control valve 43 is used to connect or disconnect the power assembly 1 with the second motor group 3. The first hydraulic control valve 42 and the second hydraulic control valve 43 cooperate to achieve the purpose of two-wheel drive, and the first control valve 41 adjusts the displacement of the first motor group 2, thereby realizing the adjustment of the motor speed during two-wheel drive to meet different driving requirements.

[0056] In some embodiments, the speed control valve assembly 4 further includes a second control valve 44 and a flow-dividing and combining valve 45. The first oil port of the second control valve 44 is connected to the first power oil port 111, and the second oil port of the second control valve 44 is connected to both the hydraulically controlled ends of the first hydraulically controlled valve 42 and the hydraulically controlled ends of the second hydraulically controlled valve 43. The second control valve 44 is used to selectively connect the hydraulically controlled end of the first hydraulically controlled valve 42 to the power assembly 1 or the fuel tank 7, and the second control valve 44 is also used to selectively connect the hydraulically controlled end of the second hydraulically controlled valve 43 to the power assembly 1 (i.e., the travel pump 11) or the fuel tank 7. The two oil outlets of the flow-dividing and combining valve 45 are connected to the first motor group 2 and the second motor group 3, respectively. The oil inlet of the flow-dividing and combining valve 45 is connected to the first power oil port 111 of the power assembly 1. The flow-dividing and combining valve 45 distributes the oil flowing out of the first power oil port 111 of the power assembly 1 to the first motor group 2 and the second motor group 3 according to a set ratio to meet the oil volume requirements of the first motor group 2 and the second motor group 3. The second control valve 44 is used to control the flow of oil to the hydraulic control ends of the first hydraulic control valve 42 and the second hydraulic control valve 43, so as to control the oil to enter the first motor group 2 and the second motor group 3 through the diverter and collector valve 45, or to control the oil to enter the first motor group 2 and the second motor group 3 through the first hydraulic control valve 42 and the second hydraulic control valve 43, thereby realizing the switching between four-wheel drive and two-wheel drive.

[0057] When the engineering vehicle is a forklift, the front wheels of the forklift are larger than the rear wheels. In this way, the amount of oil required by the motor group corresponding to the front wheels is larger than the amount of oil required by the motor corresponding to the rear wheels. The diverter and collector valve 45 can distribute the oil proportionally according to the actual needs of the first motor group 2 and the second motor group 3.

[0058] In some embodiments, the two oil outlets of the flow dividing and combining valve 45 are connected through a first throttle 46. For example, the first throttle 46 is a damping hole provided in the flow dividing and combining valve 45 to limit the flow between the two oil outlets of the flow dividing and combining valve 45.

[0059] The first motor group 2 is connected to the power assembly 1 to form a circulation loop. The circulation of oil will cause the oil temperature to be unable to cool down, affecting the operation of the first motor group 2. For this reason, in some embodiments, the speed control valve group 4 also includes a first one-way valve 47. The first one-way valve 47 is connected to the third power oil port 121 and the diverter and collector valve 45. The first one-way valve 47 is limited to the oil flowing from the third power oil port 121 to the diverter and collector valve 45. After passing through the third power oil port 121, the oil enters the first motor group 2 through the first one-way valve 47 to provide new oil for the first motor group 2.

[0060] In some embodiments, as Figure 3 As shown, the switching valve assembly 5 includes a first switching valve 51 and a second switching valve 52. The first oil port of the first switching valve 51 is connected to the third power oil port 121, and the second oil port of the first switching valve 51 is connected to the pilot end of the second switching valve 52. The second switching valve 52 is used to selectively connect or disconnect the first power oil port 111 from the second motor group 3. In other words, the third power oil port 121 can provide oil to the first switching valve 51 to enter the pilot end of the second switching valve 52. This ensures that the second switching valve 52 can connect or disconnect the speed control valve group 4 from the second motor group 3 according to actual needs, thereby achieving the purpose of switching to two-wheel drive or four-wheel drive.

[0061] In some embodiments, the second oil port of the first switching valve 51 is connected to the fuel tank 7 via a second throttle member 53, which in turn is connected to the fuel tank 7 via a second one-way valve 10. Specifically, the oil outlet of the second throttle member 53 serves as a feedback oil port and is connected to the oil inlet of the second one-way valve 10. The second one-way valve 10 limits oil flow from the third power oil port 121 to the second throttle member 53. The arrangement of the second throttle member 53 and the second one-way valve 10 ensures that oil pressure does not build up after entering the pilot end of the second switching valve 52, maintaining the second switching valve 52 in the lower position. The second one-way valve 10 limits the pressure of the second throttle member 53 to ensure that the oil pressure at the pilot end of the second switching valve 52 is maintained. For example, the second throttle member 53 can be a throttle valve.

[0062] The third oil port of the first switching valve 51 is defined as the first switching valve third oil port 513 .

[0063] In some embodiments, the switching valve assembly 5 includes a third one-way valve 54, which is connected to the third oil port 513 of the first switching valve. The third one-way valve 54 only allows oil to flow from the third oil port 513 of the first switching valve to the first oil port of the second motor assembly 3. The first switching valve 51 is used to selectively connect the second oil port of the second motor assembly 3 to the third one-way valve 54. The third one-way valve 54 is used to replenish oil to the system.

[0064] For example, the second switching valve 52 is a two-position, four-way pilot valve having a first oil port, a second oil port, a third oil port, and a fourth oil port. When the coil of the first switching valve 51 is energized, the left position is open. At this time, the pressurized oil in the first switching valve 51 is disconnected from the pilot port of the second switching valve 52. The fourth oil port of the second switching valve 52 is connected to the second oil port of the second switching valve 52, and the first oil port of the second switching valve 52 is connected to the third oil port of the second switching valve 52, thereby achieving four-wheel drive. When the coil of the first switching valve 51 is de-energized, the right position is open. At this time, the oil in the first switching valve 51 is connected to the pilot port of the second switching valve 52, and the fourth oil port of the second switching valve 52 is connected to the third oil port of the second switching valve 52. This prevents the oil from entering the second motor unit 3, thereby achieving two-wheel drive.

[0065] Continue to refer Figure 1 The hydraulic travel system also includes a parking valve 6. Its first oil port is connected to the third power oil port 121, and its second oil port is connected to the brake oil port of the first motor unit 2. When the coil of the parking valve 6 is energized, the right position is open, and the third power oil port 121 connects to the parking valve 6 through the first oil port of the parking valve 6. Oil then enters the brake 25, releasing the brake. When the coil of the parking valve 6 is de-energized, the left position is open, and the third power oil port 121 connects to the second oil port of the parking valve 6 through the third oil port of the parking valve 6. Oil then flows out of the brake 25 and into the fuel tank 7, applying the brake.

[0066] Combine Figure 1 and Figure 4The power assembly 1 includes a travel pump 11 and a replenishing oil pump 12. The travel pump 11 has a first power oil port 111 and a second power oil port 112. The travel pump 11 provides oil to the first motor group 2 and the second motor group 3, while the replenishing oil pump 12 has a third power oil port 121. The replenishing oil pump 12 provides oil to the hydraulic control end and the pilot end of the system and can replenish oil to the first motor group 2. The power assembly 1 also includes a pressure relief member 13. The oil inlet of the pressure relief member 13 is connected to the first power oil port 111 and the second power oil port 112 respectively, and the oil outlet of the pressure relief member 13 is connected to the oil tank 7. The pressure relief member 13 can unload the oil with low pressure in the first power oil port 111 and the second power oil port 112 into the oil tank 7. The specific structure of the pressure relief member 13 is existing technology and will not be repeated in this embodiment.

[0067] For ease of explanation, the second oil port of the second switching valve 52 is referred to as the second switching valve second oil port 522, the first oil port of the second switching valve 52 is referred to as the second switching valve first oil port 521, the third oil port of the second switching valve 52 is referred to as the second switching valve third oil port 523, and the fourth oil port of the second switching valve 52 is referred to as the second switching valve fourth oil port 524. The first oil port of the third motor 31 is referred to as the third motor first oil port 311, the second oil port of the third motor 31 is referred to as the third motor second oil port 312, the first oil port of the fourth motor 32 is referred to as the fourth motor first oil port 321, and the second oil port of the fourth motor 32 is referred to as the fourth motor second oil port 322. The first oil port of the second control valve 44 is referred to as the second control valve first oil port 441, the second oil port of the second control valve 44 is referred to as the second control valve second oil port 442, and the third oil port of the second control valve 44 is referred to as the second control valve third oil port 443. The first oil port of the first switching valve 51 is the first switching valve first oil port 511 , and the second oil port of the first switching valve 51 is the first switching valve second oil port 512 .

[0068] Combine Figures 1 to 6 The working principle of the hydraulic travel system is as follows:

[0069] When the construction vehicle is moving, the coil of parking valve 6 is energized, releasing the brakes and ensuring normal motor rotation. The oil flow is as follows: oil from travel pump 11 is delivered via third power oil port 121 to the inlet of line filter 8. After exiting line filter 8, a portion of the oil enters the first oil port of parking valve 6. The coil of parking valve 6 is energized, and oil is delivered via the second oil port of parking valve 6 to the brake disc inlets of first motor 21 and second motor 22, releasing the brakes.

[0070] Working principle of four-wheel drive climbing mode:

[0071] Take forward as an example:

[0072] At this point, the travel pump 11 rotates, drawing oil from the fuel tank 7. High-pressure oil is then delivered from the first power oil port 111, which is then piped to the first oil port 441 of the second control valve, the first oil port of the first hydraulic control valve 42, the first oil port of the second hydraulic control valve 43, and the first oil port of the diverter / combiner valve 45. The coil of the second control valve 44 is energized, and some oil flows through the first oil port 441 and then through the second oil port 442 of the second control valve to the spring chambers of the first and second hydraulic control valves 42, 43, respectively. The oil then holds the first and second hydraulic control valves 42, 43 in the closed position, effectively blocking their respective valve cores. The high-pressure oil is then distributed through the diverter / combiner valve 45 to the first motor unit 2 and the switching valve unit 5 according to the distribution ratio of the valve cores.

[0073] The coil of the first switching valve 51 of the switching valve group 5 is energized, and oil is taken in by the pilot end of the second switching valve 52 through the first oil port 511 and the second oil port 512 of the first switching valve 51. The second switching valve 52 is in the conducting position, the second oil port 522 of the second switching valve is connected with the fourth oil port 524 of the second switching valve, and the first oil port 521 of the second switching valve is connected with the third oil port 523 of the second switching valve; the high-pressure oil in the second oil port 522 of the second switching valve flows to the fourth oil port 524 of the second switching valve, and after flowing out of the fourth oil port 524 of the second switching valve, it flows through the pipeline to the first oil port 311 of the third motor and the first oil port 321 of the fourth motor to drive the motor to rotate. The low-pressure oil of the third motor 31 is connected through the second oil port 312 of the third motor, and the low-pressure oil of the fourth motor 32 is connected through the second oil port 322 of the fourth motor and returned to the third oil port 523 of the second switching valve through the second switching valve 52, and returned to the first oil port 521 of the second switching valve; the oil flowing out of the second oil port of the first motor 21 and the second oil port of the second motor 22 flows through the pipeline together with the oil of the first oil port 521 of the second switching valve to the second power oil port 112 of the travel pump 11 to form a closed loop. The oil return from each motor housing (which can enter radiator 9, and if the motor housing oil return requires no back pressure or very low back pressure, lower than the pressure caused by radiator 9 and pipeline losses, the motor housing oil return must be directly connected to the oil return port of fuel tank 7), the oil return port of switching valve group 5 (i.e., first switching valve third oil port 513), and the oil return port of speed control valve group 4 (i.e., second control valve third oil port 443 and / or first control valve third oil port 413) are all connected via pipelines to the oil inlet of radiator 9, and then return to fuel tank 7 after heat dissipation in radiator 9. The entire engineering vehicle achieves four-wheel climbing mode travel drive.

[0074] The reverse mode of the engineering vehicle is similar to the forward mode. The difference is that when reversing, the oil flows out through the second power oil port 112 of the travel pump 11. After the high-pressure oil passes through the switching valve group 5, the speed control valve group 4 and each motor, the oil pressure is reduced to low-pressure oil, and the low-pressure oil returns to the first power oil port 111 of the travel pump 11. The control logic is the same.

[0075] Working principle of two-wheel drive low speed mode:

[0076] Take forward as an example:

[0077] The travel pump 11 draws oil from the oil tank 7, and the first power oil port 111 of the travel pump 11 outputs high-pressure oil, which is transmitted to the speed control valve group 4 through the pipeline. At this time, the coil of the second control valve 44 shall not be energized, and the valve core of the second control valve 44 is in the default position. The second oil port 442 of the second control valve and the spring chamber control port of the second hydraulic control valve 43 and the spring chamber control port of the first hydraulic control valve 42 are all connected. The second oil port 442 of the second control valve is connected to the third oil port 443 of the second control valve, and the third oil port 443 of the second control valve is connected to the oil tank 7. The high-pressure oil cannot pass through the second control valve 44 into the spring chamber control port of the second hydraulic control valve 43 and the first hydraulic control valve 42, and the control oil introduced from the respective first oil ports of the second hydraulic control valve 43 and the first hydraulic control valve 42 will When the valve core is pushed to its respective conduction position, the high-pressure oil can enter the second motor group 3 and the first motor group 2 through the second hydraulic control valve 43 and the first hydraulic control valve 42, wherein the high-pressure oil flowing out of the second oil port of the first hydraulic control valve 42 flows through the pipeline to the first oil port of the first motor group 2 to drive the motor to rotate, and the high-pressure oil flowing out of the second oil port of the second hydraulic control valve 43 flows through the pipeline to the second oil port 522 of the second switching valve of the switching valve group 5; the coil of the first control valve 41 is not energized, then the oil flows back to the oil tank 7 through the second oil port 412 of the first control valve and the third oil port 413 of the first control valve, and no oil enters the first displacement regulating valve 23 and the second displacement regulating valve 24 of the first motor group 2, and each motor of the first motor group 2 remains in the default large displacement working condition.

[0078] The coil of the first switching valve 51 is de-energized. The output oil of the charge pump 12 is delivered to the input port of the line filter 8 through the third power oil port 121. After exiting the line filter 8, a portion of the oil enters the switching valve assembly 5. The oil then flows through the first switching valve 51 to the pilot port of the second switching valve 52. This means that oil enters the pilot port of the second switching valve 52, and the second switching valve 52 is in the lower position. At this point, the second switching valve 52 is blocked, and the oil flow from the second hydraulic control valve 43 is blocked. No high-pressure oil enters the rear wheels. The second throttle member 53 allows the oil entering the pilot port of the second switching valve 52 through the first switching valve 51 to maintain flow, thereby ensuring that the second switching valve 52 remains stably in the lower position and prevents high-pressure oil from entering the second motor unit 3. The oil then flows through the second oil port of the first motor unit 2 and through the pipeline to the second power oil port 112 of the travel pump 11, forming a closed loop. The oil return from each motor housing (if it can enter radiator 9, and if the motor housing oil return requires no back pressure or very low back pressure, lower than the pressure caused by radiator 9 and pipeline losses, then the motor housing oil return must be directly connected to the oil return port of fuel tank 7), the oil return port of switching valve group 5 (i.e., the third oil port 513 of the first switching valve), and the oil return port of speed control valve group 4 (i.e., the third oil port 443 of the second control valve and / or the third oil port 413 of the first control valve) are collectively connected via pipelines to the oil inlet of radiator 9. After heat is dissipated by radiator 9, it returns to fuel tank 7. The entire vehicle achieves two-wheel drive low-speed driving mode.

[0079] The reverse mode is similar to the forward mode, except that when reversing, the high-pressure oil output port of the travel pump 11 becomes the second power oil port 112 of the travel pump 11, and the high-pressure oil returns to the first power oil port 111 of the travel pump 11 through the speed control valve group 4 and the second oil port of the first motor group 2. The control logic is the same.

[0080] Working principle of two-wheel drive high-speed mode:

[0081] Take forward as an example:

[0082] The travel pump 11 draws oil from the oil tank 7, and the first power oil port 111 of the travel pump 11 outputs high-pressure oil, which is transmitted to the speed control valve group 4 through the pipeline. At this time, the coil of the second control valve 44 is not energized, and the valve core of the second control valve 44 is in the default position. The high-pressure oil cannot pass through the second control valve 44 to enter the spring chamber control ports of the second hydraulic control valve 43 and the first hydraulic control valve 42. The control oil introduced from the respective first oil ports of the second hydraulic control valve 43 and the first hydraulic control valve 42 pushes their respective valve cores to their respective conduction positions, that is, the oil can pass through the second hydraulic control valve 43 and the first hydraulic control valve 42 to the first motor group 2 and the switching valve group 5. The coil of the first control valve 41 is energized, and the second oil port 412 of the first control valve is connected to the third power oil port 121 through the first oil port 411 of the first control valve, and the oil enters the variable displacement oil port of the first motor group 2, so that the motor remains in the low-displacement operating condition.

[0083] The coil of the first switching valve 51 of the switching valve group 5 shall not be energized, and the output oil of the oil replenishment pump 12 is output to the input port of the pipeline filter 8 through the third power oil port 121. After the oil comes out of the pipeline filter 8, a part of it enters the switching valve group 5, and the oil is passed through the first oil port 511 of the first switching valve 51 and the second oil port 512 of the first switching valve to the pilot end of the second switching valve 52, that is, oil enters the pilot end of the second switching valve 52, and the second switching valve 52 is in the lower position. At this time, the second switching valve 52 is cut off, and the oil of the second hydraulic control valve 43 is cut off, and no high-pressure oil enters the rear wheel. The second throttle member 53 can enable the oil to enter the pilot end of the second switching valve 52 through the first switching valve 51 to maintain flow, thereby ensuring that the second switching valve 52 can always be stably maintained in the lower position, ensuring that the high-pressure oil cannot enter the second motor group 3.

[0084] After passing through the second oil port of the first motor assembly 2, the oil flows through a pipeline to the second power oil port 112 of the travel pump 11, forming a closed loop. The motor housing return oil (which can enter the radiator 9, if the motor housing return oil requires no back pressure or a very low back pressure, lower than the pressure caused by radiator 9 and pipeline losses, then the motor housing return oil must be directly connected to the oil return port of the fuel tank 7), the oil return port of the switching valve assembly 5 (i.e., the third oil port 513 of the first switching valve), and the oil return port of the speed control valve assembly 4 (i.e., the third oil port 443 of the second control valve and / or the third oil port 413 of the first control valve) all enter the oil inlet of the radiator 9 through a pipeline. After dissipation of heat in the radiator 9, the oil returns to the fuel tank 7. The entire vehicle achieves two-wheel drive low-speed travel mode.

[0085] The reverse mode is similar to the forward mode, except that when reversing, the high-pressure oil output port of the travel pump 11 becomes the second power oil port 112 of the travel pump 11, and the high-pressure oil returns to the first power oil port 111 of the travel pump 11 after passing through the first motor group 2 and the speed control valve group 4. The control logic is the same.

[0086] The present invention also provides an engineering vehicle, which includes the hydraulic travel system provided by the present invention.

[0087] The engineering vehicle provided by the present invention includes a hydraulic walking system. The hydraulic walking system adjusts the speed of the first motor group 2 through the speed control valve group 4 so that the first motor group 2 can achieve different speeds of travel in the two-wheel drive state. The switching valve group 5 is used to connect the travel pump 11 with the second motor group 3, so that the engineering vehicle can climb the slope in the four-wheel drive mode. The speed control valve group 4 and the switching valve group 5 cooperate with each other to enable the engineering vehicle to travel in the four-wheel drive mode, the two-wheel drive low-speed mode and the two-wheel drive high-speed mode, thereby meeting the walking requirements under different working conditions and improving the working efficiency of the engineering vehicle.

[0088] Since the engineering vehicle includes the above-mentioned hydraulic travel system, the engineering vehicle of the embodiment of the present invention has all the advantages and beneficial effects of the above-mentioned embodiments, which will not be described in detail here.

[0089] Furthermore, the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A hydraulic travel system, characterized in that: include: A power assembly (1) including a travel pump (11); A first motor group (2) and a second motor group (3), wherein the first motor group (2) is used to drive two wheels of the engineering vehicle to rotate and move, and the second motor group (3) is used to drive the other two wheels of the engineering vehicle to rotate and move, and the first motor group (2) and the second motor group (3) are respectively connected to the travel pump (11) to form a circulation loop; A speed control valve group (4), the speed control valve group (4) is connected to the travel pump (11) to distribute oil to the first motor group (2) and the second motor group (3), and the speed control valve group (4) is configured to at least adjust the speed of the first motor group (2); the speed control valve group (4) includes a second hydraulic control valve (43) and a diverter / collector valve (45), the second motor group (3) is selectively connected to the travel pump (11) through the second hydraulic control valve (43), the two oil outlets of the diverter / collector valve (45) are respectively connected to the first motor group (2) and the second motor group (3), and the oil inlet of the diverter / collector valve (45) is connected to the first power oil port (111) of the travel pump (11); a switching valve group (5), the switching valve group (5) being used to selectively connect or disconnect the speed control valve group (4) and the second motor group (3), so that the oil of the travel pump (11) selectively enters the second motor group (3); the switching valve group (5) comprising a first switching valve (51) and a second switching valve (52); the first switching valve (51) being connected to the oil pump (12); the first switching valve (51) being connected to the pilot end of the second switching valve (52); and the second switching valve (52) being used to selectively connect or disconnect the flow dividing and combining valve (45) or the second hydraulic control valve (43) with the second motor group (3); The hydraulic travel system includes a four-wheel drive climbing mode, a two-wheel drive high-speed travel mode, and a two-wheel drive low-speed travel mode. In the four-wheel drive climbing mode, the motors in the first motor group (2) and the second motor group (3) are both drive motors. In the two-wheel drive high-speed travel mode, the motor in the first motor group (2) is the drive motor, and the motor in the second motor group (3) connected to the rear wheel is the follower motor. In the two-wheel drive low-speed walking mode, the motor in the first motor group (2) is a driving motor, and the motor in the second motor group (3) connected to the rear wheel is a follower motor.

2. The hydraulic travel system according to claim 1, characterized in that: The power assembly (1) further includes an oil replenishing pump (12), the speed control valve group (4) includes a first control valve (41) and a first hydraulic control valve (42), the first hydraulic control valve (42) and the second hydraulic control valve (43) are both connected to the travel pump (11), the first motor group (2) is selectively connected to the travel pump (11) through the first hydraulic control valve (42), the first control valve (41) is connected to the oil replenishing pump (12), and the first control valve (41) is connected to the displacement regulating valve of the first motor group (2) to regulate the displacement of the first motor group (2).

3. The hydraulic travel system according to claim 2, characterized in that: The speed control valve group (4) further includes a second control valve (44), the second control valve (44) being respectively connected to the travel pump (11), the oil tank (7), the hydraulic control end of the first hydraulic control valve (42), and the hydraulic control end of the second hydraulic control valve (43), the second control valve (44) being used to selectively connect the hydraulic control end of the first hydraulic control valve (42) to the travel pump (11) or the oil tank (7), and the second control valve (44) being also used to selectively connect the hydraulic control end of the second hydraulic control valve (43) to the travel pump (11) or the oil tank (7).

4. The hydraulic travel system according to claim 1, characterized in that: The two oil outlets of the flow dividing and combining valve (45) are connected via a first throttle member (46).

5. The hydraulic travel system according to claim 1, characterized in that: The speed control valve group (4) further includes a first one-way valve (47), which is used to connect the oil replenishment pump (12) and the diverter / collector valve (45), and the first one-way valve (47) is limited to only allowing oil to flow from the oil replenishment pump (12) to the diverter / collector valve (45).

6. The hydraulic travel system according to claim 1, characterized in that: The first switching valve (51) is connected to the oil tank (7) via a second throttle member (53); The second throttling member (53) is connected to the oil tank (7) via a second one-way valve (10), and the second one-way valve (10) only allows oil to flow from the travel pump (11) to the second throttling member (53).

7. The hydraulic travel system according to claim 1, characterized in that: The switching valve group (5) further includes a third one-way valve (54), which is connected to the first switching valve (51). The third one-way valve (54) is limited to allowing oil to flow from the first switching valve (51) to the first oil port of the second motor group (3). The first switching valve (51) is used to selectively connect the second oil port of the second motor group (3) to the third one-way valve (54).

8. The hydraulic travel system according to claim 1, characterized in that: The power assembly (1) further includes an oil replenishing pump (12), and the hydraulic travel system further includes a parking valve (6), wherein the parking valve (6) is used to selectively connect the brake oil port of the first motor group (2) to the oil replenishing pump (12) or the oil tank (7) to apply or release the brakes of the first motor group (2).

9. An engineering vehicle, characterized in that: Comprising the hydraulic travel system according to any one of claims 1 to 8.

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