Hydraulic walking system and engineering vehicle

Abstract

The invention relates to the field of vehicles, in particular to a hydraulic walking system and an engineering vehicle. The hydraulic walking system comprises a power assembly, a first motor set, a second motor set, a speed control valve set and a switching valve set, according to the hydraulic walking system and the engineering vehicle, the rotating speed of the first motor set is adjusted through the speed control valve set, so that the first motor set walks at different rotating speeds in the two-drive state, and the working efficiency is improved. And the switching valve group is used for communicating the walking pump with the second motor group, so that the engineering vehicle can climb and walk in a four-wheel drive mode, and the speed control valve group and the switching valve group are matched with each other, so that the engineering vehicle can walk in the four-wheel drive mode, a two-wheel drive low-speed mode and a two-wheel drive high-speed mode, the walking requirements under different working conditions are met, and the working efficiency of the engineering vehicle is improved. The working efficiency of the engineering vehicle is improved.

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 the switching mode between two-wheel drive and four-wheel drive. However, in the prior art, 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, the speed control valve group being connected to the travel pump to distribute oil to the first motor group and the second motor group, and the speed control valve group being configured to at least adjust a rotation 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 a preferred technical solution of the above-mentioned hydraulic walking system, the power assembly also includes an oil replenishment 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 replenishment 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 flow 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 a preferred 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, the first switching valve is connected to the pilot end of the second switching valve, and the second switching valve is used to selectively connect or disconnect 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 through a second throttling 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 flow 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 oil flowing 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 replenishing 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 replenishing 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 rotational 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 the two-wheel drive state. The switching valve group is used to connect the travel pump with the second motor group, so as to enable the engineering vehicle to climb hills 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 work efficiency of the engineering vehicle.

[0023] In addition, existing internal combustion engine driven engineering vehicles use bridge drive, and the height of the bridge drive 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 the description of 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 paying any creative work.

[0025] Figure 1 A hydraulic principle diagram of a hydraulic travel system provided by 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 the middle A;

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

[0031] In the figure:

[0032] 1. Power assembly; 11. Travel pump; 111. First power oil port; 112. Second power oil port; 12. Make-up oil 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; 43, second hydraulic control valve; 44, second control valve; 441, second control valve first oil port; 442, second control valve second oil port; 443, second control valve third oil port; 45, flow dividing and collecting valve; 46, first throttling device; 47, first non-return valve; 5, switching valve group; 51, first switching valve; 511, first switching valve first oil port; 512, first switching valve second oil port; 513, first switching valve third oil port; 52, second switching valve; 521, second switching valve first oil port; 522, second switching valve second oil port; 523, second switching valve third oil port; 524, second switching valve fourth oil port; 53, second throttling device; 54, third non-return valve; 6, parking valve; 7, oil tank; 8, pipeline filter; 9, radiator; 10, second non-return valve. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] The present invention provides a hydraulic travel system, which can adjust the rotation speed of a 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: a four-wheel drive climbing mode, a two-wheel drive high-speed travel mode and a 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 walk, and the second motor group 3 is used to drive the other two wheels of the engineering vehicle to rotate and walk. 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 rotation speed of the first motor group 2; the switching valve group 5 is used to selectively connect or disconnect 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 realize the climbing walking of the engineering vehicle in the four-wheel drive mode. The speed control valve group 4 and the switching valve group 5 cooperate with each other to realize the walking of the engineering vehicle 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, 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, wherein the first motor 21 and the second motor 22 are both dual-displacement radial piston motors. For example, the first motor 21 is connected to the left front wheel to drive the left front wheel to move, and the second motor 22 is connected to the right front wheel to drive the right front wheel to move, wherein 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, and the displacement adjustment of the motor is a prior art, so the specific structure and principle of the first displacement regulating valve 23 and the second displacement regulating valve 24 are not repeated.

[0043] The first motor group 2 has a brake oil port, and 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, 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 the low-speed running of the first motor 21.

[0046] The displacement regulation of the second motor 22 is the same as the displacement regulation 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. 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 move 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 the 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 connected to 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 double displacement radial piston motors. In this case, the speed control valve group 4 is configured to simultaneously adjust the speeds of the first motor group 2 and the second motor group 3.

[0051] Of course, the first motor 21 and the second motor 22 may be fixed displacement radial piston motors, and the third motor 31 and the fourth motor 32 may be dual displacement radial piston motors.

[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 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 a driving motor, and the motor in the second motor group 3 connected to the rear wheel is a follower motor, which can rotate freely according to the forward and backward movement. Under this working condition, the first motor group 2 is a small displacement mode. This walking mode has the fastest speed and is suitable for transitions. It improves work efficiency and can avoid the problem of shortened working time due to long transition distances.

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

[0055] In some embodiments, Figure 2 and Figure 4As shown, the power assembly 1 also includes an oil replenishment 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, the second oil port of the first hydraulic control valve 42 is connected to the first motor group 2, and 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, and 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, and 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 replenishment 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 group 4 further includes a second control valve 44 and a flow dividing and collecting valve 45, wherein 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 the hydraulic control end of the first hydraulic control valve 42 and the hydraulic control end of the second hydraulic control valve 43, and the second control valve 44 is used to selectively connect the hydraulic control end of the first hydraulic control valve 42 to the power assembly 1 or the oil tank 7, and the second control valve 44 is also used to selectively connect the hydraulic control end of the second hydraulic control valve 43 to the power assembly 1 (that is, the travel pump 11) or the oil tank 7. The two oil outlets of the flow dividing and collecting valve 45 are respectively connected to the first motor group 2 and the second motor group 3, and the oil inlet of the flow dividing and collecting valve 45 is connected to the first power oil port 111 of the power assembly 1. The flow dividing and collecting valve 45 can distribute 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 the 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, so 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, which is arranged 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 component 1 to form a circulation loop. The circulation of oil will cause the oil temperature to be unable to cool down and affect 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, Figure 3 As shown, the switching valve group 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 with the second motor group 3. That is, 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, so that the second switching valve 52 can be ensured to connect or disconnect the speed control valve group 4 with 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 oil tank 7 through the second throttle 53, and the second throttle 53 is connected to the oil tank 7 through the second one-way valve 10. Specifically, the oil outlet of the second throttle 53 is a feedback oil port, and the oil outlet of the second throttle 53 is connected to the oil inlet of the second one-way valve 10. The second one-way valve 10 is limited to the oil flowing from the third power oil port 121 to the second throttle 53. The arrangement of the second throttle 53 and the second one-way valve 10 can ensure that the pilot end of the second switching valve 52 will not be blocked after entering the oil, so that the second switching valve 52 always maintains the lower position conduction, and the second one-way valve 10 can play a role in limiting the pressure of the second throttle 53 to ensure the oil pressure at the pilot end of the second switching valve 52. For example, the second throttle 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 group 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 is limited to the oil flowing from the third oil port 513 of the first switching valve 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. The third one-way valve 54 is used to replenish oil for the system.

[0064] For example, the second switching valve 52 is a two-position four-way pilot valve, and the second switching valve 52 has a first oil port, a second oil port, a third oil port, and a fourth oil port. After the coil of the first switching valve 51 is energized, the left position is connected, at which time the pressure oil of the first switching valve 51 is disconnected from the pilot end 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, so as to achieve the purpose of four-wheel drive. After the coil of the first switching valve 51 is de-energized, the right position is connected, at which time the oil of the first switching valve 51 is connected to the pilot end 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, so as to cut off the oil from entering the second motor group 3, so as to achieve the purpose of two-wheel drive.

[0065] Continue to refer Figure 1 The hydraulic travel system also includes a parking valve 6, the first oil port of the parking valve 6 is connected to the third power oil port 121, and the second oil port of the parking valve 6 is connected to the brake oil port of the first motor group 2. After the coil of the parking valve 6 is energized, the right position is conducted, and the third power oil port 121 is connected to the parking valve 6 through the first oil port of the parking valve 6, and then the oil enters the brake 25 to release the brake. After the coil of the parking valve 6 loses power, the left position is conducted, and the third power oil port 121 is connected to the second oil port of the parking valve 6 through the third oil port of the parking valve 6, and then the oil flows out of the brake 25 into the oil tank 7 to achieve braking.

[0066] Combination 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 for the first motor group 2 and the second motor group 3, and the replenishing oil pump 12 has a third power oil port 121. The replenishing oil pump 12 provides oil for the hydraulic control end and the pilot end of the system, and can replenish oil for 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 discharge 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 a prior art and will not be repeated in this embodiment.

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

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

[0069] When the engineering vehicle is moving, the coil of the parking valve 6 is energized, that is, the brake is released, ensuring that the motor can rotate normally. The oil flow is as follows: the travel pump 11 outputs the oil through the third power oil port 121 to the input port of the pipeline filter 8, and a part of the oil enters the first oil port of the parking valve 6 after exiting the pipeline filter 8. The coil of the parking valve 6 is energized, and the oil is output to the brake disc oil inlet of the first motor 21 and the second motor 22 through the second oil port of the parking valve 6, releasing the brake.

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

[0071] Take forward as an example:

[0072] At this time, the travel pump 11 rotates, and the travel pump 11 sucks oil from the oil tank 7. The first power oil port 111 outputs high-pressure oil, which is transmitted 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 and collector valve 45 through the pipeline. At this time, the coil of the second control valve 44 is energized, and part of the oil passes through the first oil port 441 of the second control valve and the second oil port 442 of the second control valve to reach the spring chambers of the first hydraulic control valve 42 and the second hydraulic control valve 43 respectively. At this time, the first hydraulic control valve 42 and the second hydraulic control valve 43 are kept in the cut-off position under the action of the oil, that is, the valve cores of the first hydraulic control valve 42 and the second hydraulic control valve 43 are not connected to oil. The high-pressure oil is distributed to the first motor group 2 and the switching valve group 5 according to the distribution ratio of its valve core through the diverter and collector valve 45.

[0073] The coil of the first switching valve 51 of the switching valve group 5 is energized, and the pilot end of the second switching valve 52 takes in oil through the first switching valve first oil port 511 and the first switching valve second oil port 512 of the first switching valve 51, the second switching valve 52 is in the conducting position, the second switching valve second oil port 522 is connected with the second switching valve fourth oil port 524, and the second switching valve first oil port 521 is connected with the second switching valve third oil port 523; the high-pressure oil at 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 pipeline, and returned to the first oil port 521 of the second switching valve through the second switching valve 52; 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 to the second power oil port 112 of the travel pump 11 through the pipeline together with the oil of the first oil port 521 of the second switching valve to form a closed loop. The oil return from the motor housing (such as being able to enter the radiator 9, if the motor housing oil return requires no back pressure or the back pressure requirement is very low, lower than the pressure caused by the radiator 9 and pipeline loss, the motor housing oil return needs to be directly connected to the oil return port of the oil tank 7), the oil return port of the switching valve group 5 (i.e. the third oil port 513 of the first switching valve), and the oil return port of the 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) enter the oil inlet of the radiator 9 through the pipeline, and return to the oil tank 7 after the heat is dissipated by the radiator 9. The whole engineering vehicle realizes the walking drive in the four-wheel climbing mode.

[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, and the high-pressure oil passes through the switching valve group 5, the speed control valve group 4 and each motor, and 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, and 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 cavity control port of the second hydraulic control valve 43 and the spring cavity 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 cavity control port of the second hydraulic control valve 43 and the first hydraulic control valve 42, and the control oil introduced from the first oil ports of the second hydraulic control valve 43 and the first hydraulic control valve 42 will The valve core is pushed to its respective conduction position, that is, 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 shall not be energized, then the oil passes through the second oil port 412 of the first control valve and the third oil port 413 of the first control valve to flow back to the oil tank 7, 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 is maintained at the default large displacement working condition.

[0078] The coil of the first switching valve 51 must not be energized, and the output oil of the replenishing 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 passes through the first switching valve 51 to the pilot end of the second switching valve 52, that is, the pilot end of the second switching valve 52 has oil entering, and the second switching valve 52 is in the lower position. At this time, the second switching valve 52 is cut off, the oil of the second hydraulic control valve 43 is cut off, and no high-pressure oil enters the rear wheel. The second throttle 53 can keep the oil entering the pilot end of the second switching valve 52 through the first switching valve 51 to 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. The oil flows through the second oil port of the first motor group 2 through the pipeline to the second power oil port 112 of the travel pump 11 to form a closed loop. The oil return from the motor housing (such as it can enter the radiator 9, if the motor housing oil return requires no back pressure or the back pressure requirement is very low, lower than the pressure caused by the radiator 9 and pipeline loss, the motor housing oil return needs to be directly connected to the oil return port of the oil tank 7), the oil return port of the switching valve group 5 (i.e. the third oil port 513 of the first switching valve), and the oil return port of the 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) enter the oil inlet of the radiator 9 through the pipeline, and return to the oil tank 7 after the heat is dissipated by the radiator 9. The whole vehicle realizes the walking drive of the two-wheel drive low-speed 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, and 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 shall not be 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 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 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, and the coil of the first control valve 41 is energized, then 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 is kept in a small displacement 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 replenishing 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 the oil enters the switching valve group 5, and the oil passes through the first switching valve 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 throttling member 53 can enable the oil to enter the pilot end of the second switching valve 52 through the first switching valve 51 to keep flowing, thereby ensuring that the second switching valve 52 can always be stably maintained in the lower position, and ensuring that the high-pressure oil cannot enter the second motor group 3.

[0084] The oil flows through the second oil port of the first motor group 2 through the pipeline to the second power oil port 112 of the travel pump 11 to form a closed loop. The motor housing return oil (such as can enter the radiator 9, if the motor housing return oil requires no back pressure or the back pressure requirement is very low, lower than the pressure caused by the radiator 9 and the pipeline loss, the motor housing return oil needs to be directly connected to the oil return port of the oil tank 7), the oil return port of the switching valve group 5 (that is, the third oil port 513 of the first switching valve), and the oil return port of the speed control valve group 4 (that is, the third oil port 443 of the second control valve and / or the third oil port 413 of the first control valve) enter the oil inlet of the radiator 9 through the pipeline, and return to the oil tank 7 after the heat is dissipated by the radiator 9. The whole vehicle realizes the travel drive of the two-wheel drive low-speed 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, and 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 walking in the two-wheel drive state. The switching valve group 5 is used to connect the walking 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 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.

[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] In addition, the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and 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), comprising 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) being 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) being configured to at least adjust the rotation speed of the first motor group (2); A switching valve group (5), the switching valve group (5) is 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).

2. The hydraulic travel system according to claim 1, characterized in that: The power assembly (1) also includes an oil replenishment 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 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), and the second motor group (3) is selectively connected to the travel pump (11) through the second hydraulic control valve (43), the first control valve (41) is connected to the oil replenishment pump (12), and the first control valve (41) is connected to the displacement regulating valve of the first motor group (2) to adjust 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 comprises a second control valve (44) and a flow-dividing and collecting valve (45); the two oil outlets of the flow-dividing and collecting valve (45) are respectively connected to the first motor group (2) and the second motor group (3); the oil inlet of the flow-dividing and collecting valve (45) is connected to the first power oil port (111) of the travel pump (11); the second control valve (44) is 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) is 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); the second control valve (44) is 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 3, characterized in that: The two oil outlets of the flow dividing and combining valve (45) are connected via a first throttle element (46).

5. The hydraulic travel system according to claim 3, characterized in that: The speed control valve group (4) further comprises a first one-way valve (47), wherein the first one-way valve (47) is used to connect the oil replenishment pump (12) and the flow dividing and collecting valve (45), and the first one-way valve (47) is limited to the oil flow from the oil replenishment pump (12) to the flow dividing and collecting valve (45).

6. The hydraulic travel system according to claim 3, characterized in that: The switching valve group (5) includes a first switching valve (51) and a second switching valve (52), wherein the first switching valve (51) is connected to the oil replenishment pump (12), the first switching valve (51) is connected to the pilot end of the second switching valve (52), and the second switching valve (52) is used to selectively connect or disconnect the diverter and collector valve (45) or the second hydraulic control valve (43) with the second motor group (3).

7. The hydraulic travel system according to claim 6, characterized in that: The first switching valve (51) is connected to the oil tank (7) via a second throttle element (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 limits the oil flow from the travel pump (11) to the second throttling member (53).

8. The hydraulic travel system according to claim 6, characterized in that: The switching valve group (5) further comprises a third one-way valve (54), wherein the third one-way valve (54) is connected to the first switching valve (51), and the third one-way valve (54) is limited to allow oil to flow from the first switching valve (51) to the first oil port of the second motor group (3), and 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).

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

10. An engineering vehicle, characterized in that: Comprising a hydraulic travel system as described in any one of claims 1-9.

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