Vehicle driving system and control method

Abstract

The invention provides a vehicle running system and a control method. The vehicle running system comprises an oil tank, a hydraulic pump, a hydraulic motor, a speed reducer and an axle. The hydraulic pump is respectively communicated with the oil tank and the hydraulic motor and is used for supplying hydraulic oil for driving the hydraulic motor to rotate to the hydraulic motor; the hydraulic motor is connected with the axle through the speed reducer and used for providing power for the axle. An oil outlet of the hydraulic motor is provided with a load component with preset pressure; in the traveling braking process of the vehicle, when the rotating wheels reversely drag the hydraulic motor, the oil at the outlet of the motor converts the kinetic energy of the vehicle into heat energy or pressure potential energy during traveling through the load component so as to perform deceleration braking. When the crane runs, hoisting operation is not carried out, the upper vehicle does not work, the running vehicle borrows power to the upper vehicle through the hydraulic system, the situation that mechanical driving and hydraulic driving work at the same time is achieved, and the power requirement of the vehicle is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of heavy machinery, and in particular relates to a vehicle driving system and a control method. Background Art

[0002] At present, wheeled cranes, especially all-terrain cranes, are used in heavy-load driving, outdoor lifting, construction, etc. Their working environment is usually harsh, with uneven roads and poor road conditions. Crane vehicles need to shuttle back and forth between various workplaces, and in most cases carry heavy loads. The driving performance of the vehicle is severely tested and has become an important indicator that customers are increasingly concerned about.

[0003] Existing super-large multi-bridge crane vehicles mostly adopt a dual-power drive mode with mechanical power as the main drive and hydraulic power as the auxiliary drive. The mechanical power drive system relies on the engine as the power source, and provides power to the axle through the gearbox, transfer case and drive shaft, etc. It is suitable for driving on flat roads. It has the advantages of high transmission efficiency and a wide speed range. However, for super-large cranes, it also needs to travel under non-road conditions, such as low speed and high torque. The mechanical power drive system cannot meet the above working conditions, and a hydraulic auxiliary drive system needs to be added; Figure 1 This is a dual-power drive power transmission flow chart. The dual engines provide driving force for the driving axle 1 and the driving axle 2 of the multi-bridge vehicle respectively, thereby driving the entire vehicle.

[0004] Hydraulic drive principle Figure 2 As shown, it includes structures such as a hydraulic pump, an oil tank, a reversing valve, a hydraulic motor, a reducer, and an axle. The engine drives the hydraulic pump to supply hydraulic oil to the hydraulic motor, and the hydraulic motor is directly connected to the axle to provide power for the vehicle.

[0005] Technical solutions of existing technology: like Figure 3As shown, Patent 1 "Hydraulic Assisted Drive System and Engineering Machinery Vehicle" (Announcement No.: CN105329096A) provides a hydraulic assisted drive system and engineering machinery vehicle, wherein the hydraulic assisted drive system is applied to the vehicle, including a hydraulic motor, a hydraulic pump, a switch valve and a controller, wherein the hydraulic motor is used to provide driving force for the vehicle; the hydraulic pump is used to supply hydraulic oil to the hydraulic motor to drive the hydraulic motor to rotate; the switch valve is located on the bypass oil circuit connecting the oil ports at both ends of the hydraulic motor, and is used to connect or disconnect the bypass oil circuit: the controller is connected to the switch valve, and the controller can control the switch valve according to the vehicle speed, so that the hydraulic assisted drive system is effective or ineffective during the driving process of the vehicle. The control process of the present invention mainly relies on the controller to adjust the switch valve according to the vehicle speed, so that the hydraulic assisted drive system can be effective or ineffective during the driving process of the vehicle without stopping the vehicle, which overcomes the problem that the hydraulic transmission system in the prior art cannot be used during the driving process of the vehicle, and the operation is simple.

[0006] like Figure 4 As shown, Patent 2 "Engineering Vehicle and Its Hydraulic Drive System" (Publication No.: CN113928981A) discloses an engineering vehicle and its hydraulic drive system, wherein the hydraulic drive system includes a boarding hydraulic system, a disembarking auxiliary drive system, and a common variable pump for supplying oil to the two systems, and the disembarking auxiliary drive system includes a working motor, a motor control valve for switching and controlling the working motor, and an electronically controlled stop valve in the disembarking auxiliary oil supply oil circuit between the motor control valve and the common variable pump. The present invention optimizes the hydraulic drive system of the engineering vehicle, and the boarding hydraulic system and the disembarking auxiliary drive system share a variable pump, making the power system more compact and reducing the cost of the whole machine; the disembarking auxiliary drive system can be turned on or off by the electronically controlled stop valve to prevent the boarding and disembarking systems from working at the same time. When the boarding hydraulic system is not working, the forward and reverse rotation of the disembarking working motor can be switched by the motor control valve, and finally the forward and backward rotation of the engineering vehicle can be realized, thereby improving the passing performance of the engineering vehicle on low-adhesion roads and roads with large slopes.

[0007] like Figure 5As shown, Patent 3 "Reducer, Hydraulic Drive System and Dual Power Drive System" (Publication No.: CN105501056A) relates to a reducer, a hydraulic drive system and a dual power drive system, wherein the reducer includes a first shaft, a second shaft and a clutch device, the clutch device includes an air control unit and a transmission unit, the transmission unit is connected to the first shaft, and the air control unit provides air pressure to drive the transmission unit to reciprocate, thereby enabling the first shaft to engage and disengage with the second shaft. In the present invention, when the first shaft and the second shaft are engaged, the drive torque provided by the hydraulic motor can be amplified by the reducer and transmitted to the axle. By amplifying the drive torque, the power of the hydraulic drive system can be made equivalent to the power of the mechanical drive system, thereby improving the driving performance of the hydraulic drive system. When the first shaft and the second shaft are disconnected, the power transmission between the hydraulic motor and the axle can be disconnected, and the hydraulic drive system can be selectively used.

[0008] However, the prior art for hydraulic driving of engineering vehicles still remains at how to use the hydraulic driving system and only provides forward and reverse functions for the vehicle, without realizing the function of deceleration braking during forward movement.

[0009] The driving system of a heavy-duty wheeled crane with multiple axles should have three basic functions: forward, reverse and braking, and should be responsive and reliable. In addition to the general air brake system, the current heavy-duty vehicle driving brake system is also equipped with engine retarding brake, gearbox retarding brake and eddy current retarding brake, etc. However, some vehicles still have insufficient braking force and cannot meet the requirements of safe driving. Summary of the invention

[0010] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a vehicle driving system and a control method. In order to achieve the above purpose / solve the above technical problems, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a vehicle travel system, including a fuel tank, a hydraulic pump, a hydraulic motor, a reducer and a vehicle axle; The hydraulic pump is connected to the oil tank and the hydraulic motor respectively, and is used to supply hydraulic oil to the hydraulic motor for driving the hydraulic motor to rotate; The hydraulic motor is connected to the axle via a reducer to provide power to the axle; The oil outlet of the hydraulic motor is provided with a load component having a preset pressure; When the vehicle is in the driving braking process, when the rotating wheels pull the hydraulic motor back, the oil at the motor outlet converts the vehicle's kinetic energy during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

[0011] The effect achieved by the above settings is as follows: During the vehicle's driving braking process, the rotating wheels reversely drag the hydraulic motor. When the motor's oil inlet continuously enters the oil port through active oil replenishment or negative pressure oil suction, the motor's oil outlet discharges the oil. When a load component with a certain pressure is set at the motor's oil outlet, the hydraulic motor outlet maintains a higher pressure, hindering the movement of the motor to achieve the purpose of deceleration.

[0012] Furthermore, the load component is a relief valve; one end of the relief valve is connected to the oil outlet of the hydraulic motor, and the other end is connected to the oil tank or the oil inlet of the hydraulic motor.

[0013] The effect achieved by the above settings is: by setting a certain pressure relief valve to keep the hydraulic motor outlet at a high pressure, the motor movement is hindered to achieve the purpose of deceleration. The motor outlet oil will overflow back to the oil tank or overflow back to the motor oil inlet through the relief valve. A large volume accumulator can also be connected to the motor outlet to store pressure oil. Thus, the vehicle kinetic energy during driving is converted into heat energy or pressure potential energy, achieving the purpose of vehicle deceleration and braking.

[0014] Further, the relief valve is connected to the oil outlet of the hydraulic motor via a load cartridge valve; The oil inlet of the load cartridge valve is connected to the oil outlet of the hydraulic motor, the oil outlet of the load cartridge valve is connected to the oil tank, and the control port of the load cartridge valve is connected to the oil inlet of the relief valve; The load cartridge valve is used for conducting only when the pressure of the motor oil outlet is greater than or equal to the pressure set by the relief valve, and the pressure oil at the motor oil outlet will flow back to the oil tank.

[0015] The effect achieved by the above setting is: when the load cartridge valve is used for driving braking, the motor oil outlet maintains a higher pressure, hindering the rotation of the motor and achieving the purpose of braking.

[0016] Furthermore, the load component is an accumulator; the accumulator is connected to the oil outlet of the hydraulic motor and is used to store pressurized oil.

[0017] Furthermore, the vehicle travel system also includes an oil circuit switching system; The oil circuit switching system is connected to the oil inlet and oil outlet of the hydraulic pump, and the oil inlet and oil return port of the hydraulic motor respectively, and is used to switch the running direction of the hydraulic motor.

[0018] Further, the oil circuit switching system includes a controller, a first cartridge valve, a second cartridge valve, a third cartridge valve, a fourth cartridge valve, a three-position four-way reversing valve, a first two-position three-way reversing valve, and a second two-position three-way reversing valve; When the pressure of the control ports of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve is high pressure, that is, when high-pressure oil enters, the main valve cores of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve are closed to seal the connecting oil path; when the pressure of the control ports of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve is low pressure, that is, when no high-pressure oil enters, the main valve cores of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve are opened to connect the oil path.

[0019] The P port of the three-position four-way reversing valve is connected to the outlet of the first two-position three-way reversing valve, the T port is connected to the oil tank, the A port is respectively connected to the third cartridge valve control port, the first cartridge valve control port and the A port of the second two-position three-way reversing valve, the B port is respectively connected to the fourth cartridge valve control port and the B port of the second two-position three-way reversing valve, and the three-position four-way reversing valve is controlled by the controller and is used to switch the operating direction of the hydraulic motor.

[0020] The first two-position three-way reversing valve is respectively connected to the oil outlet P of the hydraulic pump, the oil outlet B of the hydraulic motor and the P port of the three-position four-way reversing valve, and is controlled by the controller to respectively connect the P port of the three-position four-way reversing valve and the oil outlet P of the hydraulic pump or the oil outlet B of the hydraulic motor, thereby changing the connection state of the P port of the three-position four-way reversing valve.

[0021] The second two-position three-way reversing valve is connected to the A and B ports of the three-position four-way reversing valve and the control port of the second cartridge valve respectively, and is controlled by the controller to connect the control port of the second cartridge valve and the A port or B port of the three-position four-way reversing valve respectively, thereby changing the pressure of the control port of the second cartridge valve.

[0022] The first cartridge valve is respectively connected to the hydraulic motor oil return port A, the three-position four-way reversing valve port A, and the hydraulic oil tank, and is connected to the main oil circuit of the second cartridge valve and the fourth cartridge valve. The control port is controlled by the liquid pressure of the three-position four-way reversing valve port A.

[0023] The second cartridge valve is respectively connected to the hydraulic oil tank, the outlet of the second two-position three-way reversing valve, the hydraulic motor oil outlet B, and the inlet of the load cartridge valve, and is connected to the main oil circuit of the first cartridge valve and the third cartridge valve. The control port is controlled by the outlet liquid pressure of the second two-position three-way reversing valve.

[0024] The third cartridge valve is respectively connected to the oil outlet PP of the hydraulic pump, the inlet of the load cartridge valve, the A port of the three-position four-way reversing valve, and the oil outlet B of the hydraulic motor, and is simultaneously connected to the main oil circuits of the second cartridge valve and the fourth cartridge valve, and the control port is controlled by the liquid pressure of the A port of the three-position four-way reversing valve.

[0025] The fourth cartridge valve is respectively connected to the oil outlet P of the hydraulic pump, the oil return port A of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is connected to the main oil circuit of the second cartridge valve and the fourth cartridge valve. The control port is controlled by the liquid pressure of the B port of the three-position four-way reversing valve.

[0026] Furthermore, when the vehicle is in the forward mode, the controller controls the left path of the three-position four-way reversing valve to be connected (port T is connected to port B, and port P is connected to port A). The controller controls the first two-position three-way reversing valve and the second two-position three-way reversing valve to be in a power-off state. The first two-position three-way reversing valve is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve respectively; The second two-position three-way reversing valve is respectively connected to the B port of the three-position four-way reversing valve and the control port of the second cartridge valve; High-pressure oil enters the first cartridge valve and the third cartridge valve, the main valve core is closed, the first cartridge valve and the third cartridge valve are in the cut-off state, and the cartridge valves and are in the connected state. The hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, enters from the hydraulic motor return oil port A through the fourth cartridge valve, flows out from the hydraulic motor oil outlet B, and finally flows back to the oil tank through the second cartridge valve. In this process, the hydraulic motor rotates forward to drive the vehicle forward, so that the vehicle enters the forward mode.

[0027] Furthermore, when the vehicle is in the reverse mode, the controller controls the right path of the three-position four-way reversing valve to be connected (port T is connected to port A, and port P is connected to port B). The controller controls the first two-position three-way reversing valve and the second two-position three-way reversing valve to be in a power-off state. The first two-position three-way reversing valve is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve respectively; The second two-position three-way reversing valve is respectively connected to the B port of the three-position four-way reversing valve and the control port of the second cartridge valve; The high-pressure oil enters the second cartridge valve and the fourth cartridge valve, the main valve core is closed, the second cartridge valve and the fourth cartridge valve are in a cut-off state, and the first cartridge valve and the third cartridge valve are in a connected state.

[0028] The hydraulic oil flows from the hydraulic pump to the hydraulic pump outlet P, enters from the hydraulic motor outlet B through the third cartridge valve, flows out from the hydraulic motor return port A, and finally flows back to the oil tank through the first cartridge valve.

[0029] During this process, the hydraulic motor reverses to drive the vehicle backward, causing the vehicle to enter reverse mode.

[0030] Furthermore, when the vehicle enters the forward braking mode, the controller controls the left path of the three-position four-way reversing valve (port T is connected to port B, and port P is connected to port A). The first two-position three-way reversing valve and the second two-position three-way reversing valve are switched from a de-energized state to an energized state; The first two-position three-way reversing valve is connected to the hydraulic motor oil outlet B and the P port of the three-position four-way reversing valve respectively; the pilot oil for controlling the first cartridge valve and the third cartridge valve is changed from being provided at the pump outlet pipeline to being provided at the motor return oil pipeline, so that the cut-off pressure of the cartridge valve becomes higher.

[0031] The second two-position three-way reversing valve is connected to the A port of the three-position four-way reversing valve and the control port of the second cartridge valve respectively; the cut-off pressure of the cartridge valve is made the same as that of the first cartridge valve and the third cartridge valve, and the second cartridge valve is in a cut-off state.

[0032] The high-pressure oil acts on the first cartridge valve, the second cartridge valve, and the third cartridge valve, the main valve core is closed, the first cartridge valve, the second cartridge valve, and the third cartridge valve are in a cut-off state, and the fourth cartridge valve is in a connected state.

[0033] The hydraulic oil flows from the hydraulic pump to the hydraulic pump outlet P, enters from the hydraulic motor return port A through the fourth cartridge valve, and flows out from the hydraulic motor outlet B. At this time, the other three cartridge valves are in the cut-off state, and the motor return oil can only flow back to the tank from the load cartridge valve.

[0034] The load cartridge valve and the relief valve control the return oil pressure of the pipeline. When the motor return oil pipeline pressure is lower than the set pressure of the relief valve, the hydraulic motor only takes in oil but does not discharge oil. The motor oil outlet pressure rises until it is higher than the set pressure of the relief valve. Only when the motor return oil pipeline pressure is higher than the set pressure of the relief valve, can the motor return oil flow back to the tank.

[0035] The effect achieved by the above setting is: the set pressure of the overflow valve is greater than the normal working pressure of the motor oil return pipeline. In this way, when deceleration and braking are required, there will be a pressure build-up process in the motor oil return pipeline, which will hinder the forward rotation of the motor, thereby realizing the deceleration and braking function and causing the vehicle to enter the braking mode.

[0036] Further, the oil circuit switching system includes a first hydraulically controlled one-way valve, a second hydraulically controlled one-way valve, a third hydraulically controlled one-way valve, a fourth hydraulically controlled one-way valve, a fifth hydraulically controlled one-way valve, a three-position four-way reversing valve, and a two-position one-way reversing valve; The P port of the three-position four-way reversing valve is connected to the oil outlet P of the hydraulic pump, the T port is connected to the oil tank, the A port is connected to the control port of the third hydraulically controlled one-way valve and the two-position one-way reversing valve, and the B port is connected to the control ports of the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The three-position four-way reversing valve is controlled by the controller and is used to switch the operating direction of the hydraulic motor.

[0037] The two-position one-way reversing valve is connected to the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve, and is controlled by the controller to unidirectionally conduct or bidirectionally conduct the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve, thereby changing the pressure of the control port of the second hydraulically controlled one-way valve.

[0038] The first hydraulically controlled one-way valve is respectively connected to the hydraulic motor oil return port A, the hydraulic oil tank, and the three-position four-way reversing valve port B, and is also connected to the second hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The first hydraulically controlled one-way valve is controlled by the pressure of the three-position four-way reversing valve port B.

[0039] The second hydraulically controlled one-way valve is respectively connected to the two-position one-way reversing valve, the oil inlet of the load cartridge valve, the oil outlet B of the hydraulic motor, and the hydraulic oil tank, and is also connected to the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The second hydraulically controlled one-way valve is controlled by the outlet pressure of the two-position one-way reversing valve.

[0040] The third hydraulically controlled one-way valve is respectively connected to the oil return port A of the hydraulic motor, the oil outlet port P of the hydraulic pump, and the A port of the three-position four-way reversing valve, and is also connected to the first hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The third hydraulically controlled one-way valve is controlled by the pressure of the A port of the three-position four-way reversing valve.

[0041] The fourth hydraulically controlled one-way valve is respectively connected to the oil inlet of the load cartridge valve, the oil outlet B of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is also connected to the second hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The fourth hydraulically controlled one-way valve is controlled by the outlet pressure of the B port of the three-position four-way reversing valve.

[0042] The fifth hydraulically controlled one-way valve is connected to the oil outlet P of the hydraulic pump, the third hydraulically controlled one-way valve, and the fourth hydraulically controlled one-way valve respectively, and the control port is not connected to the pipeline, and is used for unidirectionally conducting the fourth hydraulically controlled one-way valve and the oil outlet P of the hydraulic pump.

[0043] Furthermore, when the vehicle enters the forward mode, the left path of the three-position four-way reversing valve is connected (port T is connected to port B, and port P is connected to port A). The two-position one-way directional valve is in the power-off state, and the A port of the three-position four-way directional valve and the control port of the second hydraulic one-way valve are connected; Pilot oil is introduced at the hydraulic pump outlet P to control different hydraulically controlled one-way valves through a three-position four-way reversing valve.

[0044] The pilot oil enters the control ports of the second hydraulically controlled one-way valve and the third hydraulically controlled one-way valve, and the main valve core opens and is in a connected state.

[0045] The hydraulic oil flows from the hydraulic pump to the hydraulic pump's oil outlet P, enters from the hydraulic motor's oil return port A through the third hydraulically controlled one-way valve, flows out of the hydraulic motor's oil outlet B, and finally flows back to the tank through the second hydraulically controlled one-way valve. During this process, the hydraulic motor rotates forward to drive the vehicle forward, putting the vehicle into forward mode.

[0046] Furthermore, when the vehicle enters the reverse mode, the controller controls the right path of the three-position four-way reversing valve to be connected (port T is connected to port A, and port P is connected to port B). The two-position one-way directional valve is in the power-off state, and the A port of the three-position four-way directional valve and the control port of the second hydraulic one-way valve are connected; Pilot oil is introduced at the oil outlet of the hydraulic pump to control different hydraulically controlled one-way valves through a three-position four-way reversing valve.

[0047] The pilot oil enters the control ports of the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve to open the main valve core, and the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve are in a connected state.

[0048] The hydraulic oil flows from the hydraulic pump to the hydraulic pump outlet P, enters from the hydraulic motor outlet B through the fourth hydraulic control check valve and the fifth hydraulic control check valve, flows out from the hydraulic motor return port A, and finally flows back to the tank through the first hydraulic control check valve. During this process, the hydraulic motor reverses to drive the vehicle backward, so that the vehicle enters the reverse mode.

[0049] When the vehicle is in forward braking mode, the controller controls the three-position four-way reversing valve to the left position (port T is connected to port B, and port P is connected to port A). The two-position one-way directional control valve is converted from a de-energized state to an energized state, unidirectionally closing the oil path from port A of the three-position four-way directional control valve to the control port of the second hydraulically controlled one-way valve, thereby making the control port of the second hydraulically controlled one-way valve have no control pressure.

[0050] The pilot oil enters the control port of the third hydraulically controlled one-way valve, the main valve core opens, and the third hydraulically controlled one-way valve is in a connected state.

[0051] The hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, enters from the hydraulic motor oil return port A through the third hydraulically controlled one-way valve, and flows out from the hydraulic motor oil outlet B.

[0052] Due to the presence of the second hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve, the motor return oil can only flow back to the oil tank from the load cartridge valve.

[0053] The load cartridge valve and the relief valve control the pipeline return oil pressure. Only when the motor return oil pipeline pressure is greater than the set pressure of the relief valve, the motor return oil can flow back to the tank.

[0054] The effect achieved by the above settings is: the set pressure of the overflow valve is greater than the normal working pressure of the motor oil return line. In this way, when deceleration and braking are required, there will be a pressure build-up process in the motor oil return line, which will hinder the motor from rotating forward, thereby achieving the deceleration and braking function and putting the vehicle into braking mode.

[0055] In a second aspect, the present invention provides a crane, comprising the vehicle travel system as described in the first aspect.

[0056] The above settings achieve the following effects: when the crane is traveling, it does not perform lifting operations, the vehicle does not work, and the traveling vehicle borrows power from the vehicle through the hydraulic system to achieve the simultaneous operation of mechanical drive and hydraulic drive to meet the power requirements of the vehicle. This patent also designs a new hydraulic system. When the vehicle needs to brake, the hydraulic system is changed to hinder the movement of the hydraulic motor, thereby providing braking force and reducing the vehicle speed.

[0057] In a third aspect, the present invention provides a method for controlling a vehicle driving system, based on the vehicle driving system described in the first aspect, comprising the following steps: When the vehicle is in forward braking mode, a load component with a preset pressure is connected to the oil outlet of the hydraulic motor, so that the motor outlet oil converts the vehicle's kinetic energy during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

[0058] The effect achieved by the above settings is as follows: During the vehicle's driving braking process, the rotating wheels reversely drag the hydraulic motor. When the motor's oil inlet continuously enters the oil port through active oil replenishment or negative pressure oil suction, the motor's oil outlet discharges the oil. When a load component with a certain pressure is set at the motor's oil outlet, the hydraulic motor outlet maintains a higher pressure, hindering the movement of the motor to achieve the purpose of deceleration.

[0059] Furthermore, the method further comprises: Determine whether the vehicle is in the forward gear position, and if so, determine whether the vehicle detects a forward signal. If both conditions are met, the vehicle enters the forward mode; If the vehicle is in a forward gear and a brake signal is detected, the vehicle enters braking mode.

[0060] If it is determined that the vehicle is in the reverse gear, the vehicle enters the reverse mode.

[0061] When the vehicle is not in the above three modes at the same time, it is determined whether the vehicle is in neutral gear. If the vehicle is in neutral gear and the vehicle speed is determined to be zero, the on / off switching valve is controlled to close and the vehicle driving ends.

[0062] If it is determined that the vehicle is in neutral but the vehicle speed is not zero, the vehicle forward gear determination is performed again.

[0063] Compared with the prior art, the present invention has the following beneficial effects: 1. During the vehicle braking process, the rotating wheels drag the hydraulic motor. When the motor oil inlet continuously enters the oil by active oil replenishment or negative pressure oil suction, the motor oil outlet discharges the oil. When the motor oil outlet is set with a load component of a certain pressure, the hydraulic motor outlet maintains a higher pressure, hindering the movement of the motor to achieve the purpose of deceleration. Reduce energy loss and improve the braking capacity of hydraulic vehicles.

[0064] 2. In view of the situation that some functions of the hydraulic drive system of a large crane vehicle cannot be realized during driving, the present invention provides a vehicle travel control system based on hydraulic drive. When the upper vehicle does not work, the driving vehicle borrows power from the upper vehicle through the hydraulic system to realize the simultaneous operation of mechanical drive and hydraulic drive to meet the power demand of the vehicle. It can not only realize the basic functions of moving forward and backward during driving, but also realize the function of deceleration and braking during the forward movement, thereby increasing the driving ability of the vehicle, improving the competitiveness of the product, and enhancing customer satisfaction with the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a dual-power drive power transmission flow chart of the prior art; Figure 2 Hydraulic principle diagram of the prior art Figure 3 It is a structural schematic diagram of the prior art CN105329096A; Figure 4 It is a structural schematic diagram of the prior art CN113928981A; Figure 5 It is a structural schematic diagram of the prior art CN105501056A; Figure 6 It is a schematic diagram of the vehicle driving control process of the present invention; Figure 7 It is a schematic diagram of the structure of the hydraulic system of the first embodiment; In the figure: 1-1, first cartridge valve; 1-2, second cartridge valve; 1-3, third cartridge valve; 1-4, fourth cartridge valve; 2, three-position four-way reversing valve; 3-1, first two-position three-way reversing valve; 3-2, second two-position three-way reversing valve; 4, relief valve; 5, oil tank; 6, load cartridge valve; 7, hydraulic pump; 8, hydraulic motor; 9, reducer; 10, axle; Figure 8 It is a schematic diagram of the hydraulic system structure of the second embodiment; In the figure: Y1-1, first hydraulically controlled one-way valve; Y1-2, second hydraulically controlled one-way valve; Y1-3, third hydraulically controlled one-way valve; Y1-4, fourth hydraulically controlled one-way valve; Y1-5, fifth hydraulically controlled one-way valve; 2, three-position four-way reversing valve; 3, two-position one-way reversing valve; 4, overflow valve; 5, oil tank; 6, load cartridge valve; 7, hydraulic pump; 8, hydraulic motor; 9, reducer; 10, axle. DETAILED DESCRIPTION

[0066] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0067] In the description of this embodiment, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this embodiment and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this embodiment. Example 1

[0068] This embodiment proposes a vehicle driving system and control method. By designing a hydraulic drive and auxiliary braking system, the vehicle can not only realize the functions of moving forward and backward, but also realize the function of braking while moving forward.

[0069] A vehicle driving system of this embodiment, such as Figure 7 As shown, it includes an oil tank 5, a hydraulic pump 7, a hydraulic motor 8, a reducer 9 and an axle 10; The hydraulic pump 7 is connected to the oil tank 5 and the hydraulic motor 8 respectively, and is used to supply hydraulic oil to the hydraulic motor 8 to drive the hydraulic motor 8 to rotate; The hydraulic motor 8 is connected to the axle 10 via a reducer 9 to provide power to the axle 10; The oil outlet of the hydraulic motor 8 is provided with a load component having a preset pressure; During the driving braking process of the vehicle, when the rotating wheels reversely drag the hydraulic motor 8, the oil at the motor outlet converts the kinetic energy of the vehicle during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

[0070] During the vehicle's driving braking process, the rotating wheels reversely drag the hydraulic motor 8. When the motor's oil inlet continuously enters the oil liquid through active oil replenishment or negative pressure oil suction, the motor's oil outlet discharges the oil liquid. When a load component with a certain pressure is set at the motor's oil outlet, the outlet of the hydraulic motor 8 maintains a higher pressure, hindering the movement of the motor to achieve the purpose of deceleration.

[0071] Preferably, the load component is a relief valve 4; one end of the relief valve 4 is connected to the oil outlet of the hydraulic motor 8, and the other end is connected to the oil tank 5 or the oil inlet of the hydraulic motor 8. The relief valve 4 is connected to the oil outlet of the hydraulic motor 8 through a load cartridge valve 6; The oil inlet of the load cartridge valve 6 is connected to the oil outlet of the hydraulic motor 8, the oil outlet of the load cartridge valve 6 is connected to the oil tank 5, and the control port of the load cartridge valve 6 is connected to the oil inlet of the relief valve 4; The load cartridge valve 6 is used to conduct only when the pressure at the motor oil outlet is greater than or equal to the pressure set by the relief valve 4, and the pressure oil at the motor oil outlet will flow back to the oil tank 5.

[0072] By setting a certain pressure relief valve 4 to keep the outlet of the hydraulic motor 8 at a high pressure, the motor movement is hindered to achieve the purpose of deceleration. The motor outlet oil will overflow back to the oil tank 5 or overflow back to the motor oil inlet through the relief valve 4. A large volume accumulator can also be connected to the motor outlet to store pressurized oil. Thus, the vehicle kinetic energy during driving is converted into heat energy or pressure potential energy, achieving the purpose of vehicle deceleration and braking.

[0073] Optionally, the load component is an accumulator; the accumulator is connected to the oil outlet of the hydraulic motor 8 and is used to store pressurized oil. The accumulator can store pressurized oil and release it after the car is started.

[0074] Specifically, the vehicle driving system further includes an oil circuit switching system; The oil circuit switching system is connected to the oil inlet and oil outlet of the hydraulic pump 7 and the oil inlet and oil return port of the hydraulic motor 8 respectively, and is used to switch the running direction of the hydraulic motor 8.

[0075] The oil circuit switching system preferably includes a controller, a first cartridge valve 1-1, a second cartridge valve 1-2, a third cartridge valve 1-3, a fourth cartridge valve 1-4, a three-position four-way reversing valve 2, a first two-position three-way reversing valve 3-1 and a second two-position three-way reversing valve 3-2; When the pressure of the control ports of the first cartridge valve 1-1, the second cartridge valve 1-2, the third cartridge valve 1-3, and the fourth cartridge valve 1-4 is high pressure, that is, when high-pressure oil enters, the main valve cores of the first cartridge valve 1-1, the second cartridge valve 1-2, the third cartridge valve 1-3, and the fourth cartridge valve 1-4 are closed, and the connecting oil path is blocked; when the pressure of the control ports of the first cartridge valve 1-1, the second cartridge valve 1-2, the third cartridge valve 1-3, and the fourth cartridge valve 1-4 is low pressure, that is, when no high-pressure oil enters, the main valve cores of the first cartridge valve 1-1, the second cartridge valve 1-2, the third cartridge valve 1-3, and the fourth cartridge valve 1-4 are opened, and the connecting oil path is connected.

[0076] The P port of the three-position four-way reversing valve is connected to the outlet of the first two-position three-way reversing valve 3-1, the T port is connected to the oil tank, the A port is respectively connected to the control port of the third cartridge valve 1-3, the control port of the first cartridge valve 1-1 and the A port of the second two-position three-way reversing valve 3-2, the B port is respectively connected to the control port of the fourth cartridge valve 1-4 and the B port of the second two-position three-way reversing valve 3-2, and the three-position four-way reversing valve 2 is controlled by the controller to switch the running direction of the hydraulic motor.

[0077] The first two-position three-way reversing valve 3-1 is respectively connected to the oil outlet P of the hydraulic pump, the oil outlet B of the hydraulic motor and the P port of the three-position four-way reversing valve 2, and is controlled by the controller to respectively connect the P port of the three-position four-way reversing valve and the oil outlet P of the hydraulic pump or the oil outlet B of the hydraulic motor, thereby changing the connectivity state of the P port of the three-position four-way reversing valve.

[0078] The second two-position three-way reversing valve 3-2 is connected to the A and B ports of the three-position four-way reversing valve 2 and the control port of the second cartridge valve 1-2 respectively, and is controlled by the controller to connect the control port of the second cartridge valve 1-2 and the A port or B port of the three-position four-way reversing valve 2 respectively, thereby changing the pressure of the control port of the second cartridge valve 1-2.

[0079] The first cartridge valve 1-1 is respectively connected to the hydraulic motor oil return port A, the three-position four-way reversing valve A port, and the hydraulic oil tank, and is connected to the main oil circuit of the second cartridge valve 1-2 and the fourth cartridge valve 1-4. The control port is controlled by the liquid pressure of the three-position four-way reversing valve A port.

[0080] The second cartridge valve 1-2 is respectively connected to the hydraulic oil tank, the outlet of the second two-position three-way reversing valve 3-2, the hydraulic motor oil outlet B, and the inlet of the load cartridge valve 6, and is connected to the main oil circuit of the first cartridge valve 1-1 and the third cartridge valve 1-3, and the control port is controlled by the outlet liquid pressure of the second two-position three-way reversing valve 3-2.

[0081] The third cartridge valve 1-3 is respectively connected to the oil outlet PP of the hydraulic pump, the inlet of the load cartridge valve 6, the A port of the three-position four-way reversing valve, and the oil outlet B of the hydraulic motor, and is simultaneously connected to the main oil circuit of the second cartridge valve 1-2 and the fourth cartridge valve 1-4, and the control port is controlled by the liquid pressure of the A port of the three-position four-way reversing valve.

[0082] The fourth cartridge valve 1-4 is respectively connected to the oil outlet P of the hydraulic pump, the oil return port A of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is connected to the main oil circuit of the second cartridge valve 1-2 and the fourth cartridge valve 1-4, and the control port is controlled by the liquid pressure of the B port of the three-position four-way reversing valve.

[0083] When the vehicle is in forward mode, the controller controls the left side of the three-position four-way reversing valve 2 to be connected (port T is connected to port B, and port P is connected to port A). The controller controls the first two-position three-way reversing valve 3-1 and the second two-position three-way reversing valve 3-2 to be in a power-off state. In the power-off state, the connection of the two-position three-way reversing valve is in accordance with Figure 8 The pipeline close to the spring is in a connected state.

[0084] The first two-position three-way reversing valve 3-1 is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve 2 respectively; The second two-position three-way reversing valve 3-2 is respectively connected to the B port of the three-position four-way reversing valve 2 and the control port of the second cartridge valve 1-2; High-pressure oil enters the first cartridge valve 1-1 and the third cartridge valve 1-3, the main valve core is closed, the first cartridge valve 1-1 and the third cartridge valve 1-3 are in the cut-off state, and the cartridge valves 1-2 and 1-4 are in the connected state. The hydraulic oil flows from the hydraulic pump 7 to the oil outlet P of the hydraulic pump, passes through the fourth cartridge valve 1-4, enters from the hydraulic motor oil return port A, flows out from the hydraulic motor oil outlet B, and finally flows back to the oil tank 5 through the second cartridge valve 1-2. In this process, the hydraulic motor rotates forward to drive the vehicle forward, so that the vehicle enters the forward mode.

[0085] When the vehicle is in reverse mode, the controller controls the three-position four-way reversing valve 2 to connect on the right (port T is connected to port A, and port P is connected to port B). The controller controls the first two-position three-way reversing valve 3-1 and the second two-position three-way reversing valve 3-2 to be in a power-off state. The first two-position three-way reversing valve 3-1 is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve 2 respectively; The second two-position three-way reversing valve 3-2 is respectively connected to the B port of the three-position four-way reversing valve 2 and the control port of the second cartridge valve 1-2; The high-pressure oil enters the second cartridge valve 1-2 and the fourth cartridge valve 1-4, the main valve core is closed, the second cartridge valve 1-2 and the fourth cartridge valve 1-4 are in the cut-off state, and the first cartridge valve 1-1 and the third cartridge valve 1-3 are in the connected state.

[0086] The hydraulic oil flows from the hydraulic pump 7 to the oil outlet P of the hydraulic pump, enters from the oil outlet B of the hydraulic motor through the third cartridge valve 1-3, flows out from the oil return port A of the hydraulic motor, and finally flows back to the oil tank 5 through the first cartridge valve 1-1.

[0087] During this process, the hydraulic motor reverses to drive the vehicle backward, causing the vehicle to enter reverse mode.

[0088] When the vehicle enters forward braking mode, the controller controls the three-position four-way reversing valve 2 to open on the left (port T is connected to port B, and port P is connected to port A). The first two-position three-way reversing valve 3-1 and the second two-position three-way reversing valve 3-2 are switched from a de-energized state to an energized state; The first two-position three-way reversing valve 3-1 is connected to the hydraulic motor oil outlet B and the P port of the three-position four-way reversing valve 2 respectively; the pilot oil for controlling the first cartridge valve 1-1 and the third cartridge valve 1-3 is changed from being provided at the pump outlet pipeline to being provided at the motor return oil pipeline, so that the cut-off pressure of the cartridge valve becomes higher.

[0089] The second two-position three-way reversing valve 3-2 is connected to the A port of the three-position four-way reversing valve 2 and the control port of the second cartridge valve 1-2 respectively; so that the cut-off pressure of the cartridge valve 1-2 is the same as that of the first cartridge valve 1-1 and the third cartridge valve 1-3, and the second cartridge valve 1-2 is in the cut-off state.

[0090] The high-pressure oil acts on the first cartridge valve 1-1, the second cartridge valve 1-2, and the third cartridge valve 1-3, the main valve core is closed, the first cartridge valve 1-1, the second cartridge valve 1-2, and the third cartridge valve 1-3 are in the cut-off state, and the fourth cartridge valve 1-4 is in the connected state.

[0091] The hydraulic oil flows from the hydraulic pump 7 to the hydraulic pump outlet P, passes through the fourth cartridge valve 1-4, enters the hydraulic motor return port A, and flows out of the hydraulic motor outlet B. At this time, the other three cartridge valves are in the cut-off state, and the motor return oil can only flow back to the tank from the load cartridge valve 6.

[0092] The load cartridge valve 6 and the relief valve 4 control the return oil pressure of the pipeline. When the motor return oil pipeline pressure is lower than the set pressure of the relief valve, the hydraulic motor 8 only takes in oil but does not discharge oil. The motor oil outlet pressure rises until it is higher than the set pressure of the relief valve 4. Only when the motor return oil pipeline pressure is higher than the set pressure of the relief valve, can the motor return oil flow back to the oil tank.

[0093] The set pressure of the relief valve is greater than the normal working pressure of the motor oil return pipeline. In this way, when deceleration braking is required, there will be a pressure accumulation process in the motor oil return pipeline, which hinders the forward rotation of the motor, thereby realizing the deceleration braking function and putting the vehicle into braking mode.

[0094] Notice, Figure 7 and Figure 8 In the figure, the solid dots indicate that the two pipelines are actually connected, and the hollow dots indicate that the two pipelines only intersect in the figure but are not actually connected.

[0095] Vehicle driving system control process: Taking a large crane as an example, the present invention designs a vehicle driving control process, the principle of which is as follows: Figure 6 As shown: At the beginning, the crane is powered on, the chassis is started, and then the hydraulic drive system is turned on, the vehicle is started, and the on-and-off switching valve is energized. Determine whether the clutch is engaged. If so, proceed to the next step, otherwise check the mechanical structure of the axle and return to the starting position. Determine whether the hydraulic drive system is effective. If so, proceed to the next step, otherwise check the control system problem and return to the starting position, then shift gears, release the handbrake, and release the footbrake. At this step, the vehicle driving system preparation stage has been completed, and the next step is to prepare for vehicle driving. First, determine whether the vehicle is in the forward gear position. If so, then determine whether the vehicle detects a forward signal. If both are met at the same time, the vehicle enters the forward mode (the oil pump is started, the motor rotates forward, and the system returns oil to the tank normally. For the specific principle, see the oil circuit conversion system). If the vehicle is in the forward gear position and a brake signal is detected, the vehicle enters the forward braking mode (the oil pump is started, the motor rotates forward, and the system returns oil to the tank at the set pressure value. For the specific principle, see the oil circuit conversion system). If the vehicle is judged to be in the reverse gear, the vehicle enters the reverse mode (the oil pump starts, the motor reverses, and the system returns oil to the tank normally. For the specific principle, see the oil circuit conversion system). When the vehicle is not in the above three modes at the same time, it is judged whether the vehicle is in neutral gear. If the vehicle is in neutral gear and the speed is judged to be zero, the handbrake is pulled, the motor is turned off, and the on / off switch valve is closed, and the vehicle driving ends. If the vehicle is judged to be in neutral gear but the vehicle speed is not zero, it returns to the vehicle forward gear judgment stage and enters the next logic judgment cycle.

[0096] The previous article has introduced the working principle of hydraulic drive, power transmission process and other aspects, which will not be repeated here. The main working idea of ​​the hydraulic auxiliary braking system is that during the vehicle's driving braking process, the rotating wheels reversely drag the hydraulic motor. When the motor oil inlet continuously enters the oil through active oil replenishment or negative pressure oil suction, the motor oil outlet discharges the oil. When a relief valve with a certain pressure is set at the motor oil outlet, the motor outlet oil will overflow back to the oil tank or overflow back to the motor oil inlet through the relief valve. A large-volume accumulator can also be connected to the motor outlet to store pressurized oil. By setting a certain pressure relief valve to keep the hydraulic motor outlet at a higher pressure, the motor movement is hindered, thereby converting the vehicle's kinetic energy during driving into heat energy or pressure potential energy, achieving the purpose of vehicle deceleration and braking. Example 2

[0097] This embodiment provides a vehicle driving system, which is mainly different from Embodiment 1 in that the oil circuit switching system uses different hydraulic valves to form different hydraulic systems to achieve the same function.

[0098] like Figure 8 As shown, the oil circuit switching system includes a first hydraulically controlled one-way valve Y1-1, a second hydraulically controlled one-way valve Y1-2, a third hydraulically controlled one-way valve Y1-3, a fourth hydraulically controlled one-way valve Y1-4, a fifth hydraulically controlled one-way valve Y1-5, a three-position four-way reversing valve 2, and a two-position one-way reversing valve 3; When the hydraulic pressure at the control ports of the first hydraulically controlled one-way valve Y1-1, the second hydraulically controlled one-way valve Y1-2, the third hydraulically controlled one-way valve Y1-3, the fourth hydraulically controlled one-way valve Y1-4 and the fifth hydraulically controlled one-way valve Y1-5 is higher than a preset value, the hydraulically controlled one-way valve is in a two-way conductive state; when the hydraulic pressure at the control ports of the first hydraulically controlled one-way valve Y1-1, the second hydraulically controlled one-way valve Y1-2, the third hydraulically controlled one-way valve Y1-3, the fourth hydraulically controlled one-way valve Y1-4 and the fifth hydraulically controlled one-way valve Y1-5 is lower than a preset value, the hydraulically controlled one-way valve is in a one-way conductive state.

[0099] The P port of the three-position four-way reversing valve 2 is connected to the oil outlet P of the hydraulic pump, the T port is connected to the oil tank, the A port is connected to the control port of the third hydraulically controlled one-way valve and the two-position one-way reversing valve, and the B port is connected to the control ports of the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The three-position four-way reversing valve is controlled by the controller and is used to switch the operating direction of the hydraulic motor.

[0100] The two-position one-way reversing valve 3 is connected to the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve Y1-2, and is controlled by the controller to unidirectionally conduct or bidirectionally conduct the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve Y1-2, thereby changing the pressure of the control port of the second hydraulically controlled one-way valve.

[0101] The first hydraulically controlled one-way valve Y1-1 is respectively connected to the hydraulic motor oil return port A, the hydraulic oil tank, and the three-position four-way reversing valve port B, and is also connected to the second hydraulically controlled one-way valve Y1-2 and the fourth hydraulically controlled one-way valve Y1-4. The first hydraulically controlled one-way valve Y1-1 is controlled by the pressure of the three-position four-way reversing valve port B.

[0102] The second hydraulically controlled one-way valve is respectively connected to the two-position one-way reversing valve 3, the oil inlet of the load cartridge valve 6, the oil outlet B of the hydraulic motor, and the hydraulic oil tank, and is also connected to the first hydraulically controlled one-way valve Y1-1 and the fourth hydraulically controlled one-way valve Y1-4. The second hydraulically controlled one-way valve Y1-2 is controlled by the outlet pressure of the two-position one-way reversing valve 3.

[0103] The third hydraulically controlled one-way valve is respectively connected to the oil return port A of the hydraulic motor, the oil outlet port P of the hydraulic pump, and the A port of the three-position four-way reversing valve, and is also connected to the first hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The third hydraulically controlled one-way valve is controlled by the pressure of the A port of the three-position four-way reversing valve.

[0104] The fourth hydraulically controlled one-way valve is respectively connected to the oil inlet of the load cartridge valve 6, the oil outlet B of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is also connected to the second hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The fourth hydraulically controlled one-way valve is controlled by the outlet pressure of the B port of the three-position four-way reversing valve.

[0105] The fifth hydraulically controlled one-way valve is connected to the oil outlet P of the hydraulic pump, the third hydraulically controlled one-way valve, and the fourth hydraulically controlled one-way valve respectively, and the control port is not connected to the pipeline, and is used for unidirectionally conducting the fourth hydraulically controlled one-way valve and the oil outlet P of the hydraulic pump.

[0106] When the vehicle enters the forward mode, the left side of the three-position four-way reversing valve 2 is connected (port T is connected to port B, and port P is connected to port A). The two-position one-way reversing valve 3 is in the power-off state, and the A port of the three-position four-way reversing valve and the control port of the second hydraulic one-way valve Y1-2 are connected; in the power-off state, the connection of the two-position three-way reversing valve is as follows Figure 8 The pipeline close to the spring is in a connected state.

[0107] Pilot oil is introduced at the hydraulic pump outlet P to control different hydraulically controlled one-way valves through the three-position four-way reversing valve 2.

[0108] The pilot oil enters the control ports of the second hydraulically controlled one-way valve Y1-2 and the third hydraulically controlled one-way valve Y1-3, the main valve core opens, and 1-2 and 1-3 are in a connected state.

[0109] The hydraulic oil flows from the hydraulic pump 7 to the hydraulic pump outlet P, passes through the third hydraulically controlled one-way valve Y1-3, enters from the hydraulic motor oil return port A, flows out from the hydraulic motor oil outlet B, and finally flows back to the oil tank 5 through the second hydraulically controlled one-way valve Y1-2. In this process, the hydraulic motor rotates forward to drive the vehicle forward, so that the vehicle enters the forward mode.

[0110] When the vehicle enters the reverse mode, the controller controls the right path of the three-position four-way reversing valve 2 to be connected (port T is connected to port A, and port P is connected to port B). The two-position one-way directional valve 3 is in the de-energized state, and the A port of the three-position four-way directional valve and the control port of the second hydraulically controlled one-way valve Y1-2 are connected; Pilot oil is introduced at the oil outlet of the hydraulic pump 7 to control different hydraulically controlled one-way valves through the three-position four-way reversing valve 2.

[0111] The pilot oil enters the control ports of the first hydraulically controlled one-way valve Y1-1 and the fourth hydraulically controlled one-way valve Y1-4, causing the main valve core to open, and the first hydraulically controlled one-way valve Y1-1 and the fourth hydraulically controlled one-way valve Y1-4 are in a connected state.

[0112] The hydraulic oil flows from the hydraulic pump 7 to the hydraulic pump outlet P, passes through the fourth hydraulically controlled one-way valve Y1-4 and the fifth hydraulically controlled one-way valve Y1-5, enters from the hydraulic motor outlet B, flows out from the hydraulic motor return port A, and finally flows back to the oil tank 5 through the first hydraulically controlled one-way valve Y1-1. In this process, the hydraulic motor reverses to drive the vehicle backward, so that the vehicle enters the reverse mode.

[0113] When the vehicle is in forward braking mode, the controller controls the three-position four-way reversing valve 2 to the left position (port T is connected to port B, and port P is connected to port A). The two-position one-way reversing valve 3 is converted from a de-energized state to an energized state, unidirectionally closing the oil circuit from port A of the three-position four-way reversing valve to the control port of the second hydraulically controlled one-way valve Y1-2, thereby making the control port of the second hydraulically controlled one-way valve Y1-2 have no control pressure.

[0114] The pilot oil enters the control port of the third hydraulically controlled one-way valve Y1-3, the main valve core opens, and the third hydraulically controlled one-way valve Y1-3 is in a connected state.

[0115] The hydraulic oil flows from the hydraulic pump 7 to the oil outlet P of the hydraulic pump, passes through the third hydraulically controlled one-way valve Y1-3, enters from the oil return port A of the hydraulic motor, and flows out from the oil outlet B of the hydraulic motor.

[0116] Due to the presence of hydraulically controlled one-way valves Y1-2 and 1-5, the motor return oil can only flow back to the oil tank from the load cartridge valve 6.

[0117] The load cartridge valve 6 and the relief valve 4 control the pipeline return oil pressure. Only when the motor return oil pipeline pressure is greater than the set pressure of the relief valve, the motor return oil can flow back to the oil tank.

[0118] The effect achieved by the above settings is: the set pressure of the overflow valve is greater than the normal working pressure of the motor oil return line. In this way, when deceleration and braking are required, there will be a pressure build-up process in the motor oil return line, which will hinder the motor from rotating forward, thereby achieving the deceleration and braking function and putting the vehicle into braking mode.

[0119] In addition, it should be noted that: The control valve or reversing valve used in the design of the present invention is not limited to the reversing function shown in the embodiment, and other structural valves that can achieve the same function are also protected. For example, the hydraulic one-way valve in the scheme can be replaced by an electromagnetic reversing valve or an air-controlled valve, and the one-way stop electromagnetic reversing valve can also be replaced by a two-way stop electromagnetic reversing valve.

[0120] This solution only demonstrates the application of the travel system and control method on large crane vehicles, but this solution is also applicable to other engineering vehicles.

[0121] This solution only provides the hydraulic auxiliary braking function and principle during the forward movement. Considering that the vehicle's reverse speed is generally not high, the vehicle usually does not need to be equipped with an auxiliary braking system. Therefore, this patent does not directly provide an introduction to the auxiliary braking function during the reverse movement of the vehicle. However, according to this patent, the auxiliary braking function during the reverse movement of the vehicle can be realized with a slight modification, which should also be included in the scope of the present invention. Example 3

[0122] This embodiment provides a crane, including the vehicle travel system as described in Example 1 or Example 2.

[0123] When the crane is in motion, it does not perform lifting operations and the upper vehicle does not work. The moving vehicle borrows power from the upper vehicle through the hydraulic system to achieve the simultaneous operation of mechanical drive and hydraulic drive to meet the power requirements of the vehicle. This patent also designs a new hydraulic system. When the vehicle needs to brake, the hydraulic system is changed to hinder the movement of the hydraulic motor, thereby providing braking force and reducing the vehicle speed. Example 4

[0124] This embodiment provides a control method for a vehicle driving system, based on the vehicle driving system described in Embodiment 1 or Embodiment 2, comprising the following steps: When the vehicle is in forward braking mode, a load component with a preset pressure is connected to the oil outlet of the hydraulic motor, so that the motor outlet oil converts the vehicle's kinetic energy during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

[0125] During the vehicle's driving braking process, the rotating wheels drag the hydraulic motor back. When the motor's oil inlet continuously enters the oil liquid through active oil replenishment or negative pressure oil suction, the motor's oil outlet discharges the oil liquid. When a load component with a certain pressure is set at the motor's oil outlet, the hydraulic motor outlet maintains a higher pressure, hindering the movement of the motor to achieve the purpose of deceleration.

[0126] Taking a large crane as an example, the present invention designs a vehicle driving control process, the principle of which is as follows: Figure 6 As shown: At the beginning, the crane is powered on, the chassis is started, and then the hydraulic drive system is turned on, the vehicle is started, and the on-and-off switching valve is energized. Determine whether the clutch is engaged. If so, proceed to the next step, otherwise check the mechanical structure of the axle and return to the starting position. Determine whether the hydraulic drive system is effective. If so, proceed to the next step, otherwise check the control system problem and return to the starting position, then shift gears, release the handbrake, and release the footbrake. At this step, the vehicle driving system preparation stage has been completed, and the next step is to prepare for vehicle driving. First, determine whether the vehicle is in the forward gear position. If so, then determine whether the vehicle detects a forward signal. If both are met at the same time, the vehicle enters the forward mode (the oil pump is started, the motor rotates forward, and the system returns oil to the tank normally. For the specific principle, see the oil circuit conversion system). If the vehicle is in the forward gear position and a brake signal is detected, the vehicle enters the forward braking mode (the oil pump is started, the motor rotates forward, and the system returns oil to the tank at the set pressure value. For the specific principle, see the oil circuit conversion system). If the vehicle is judged to be in the reverse gear, the vehicle enters the reverse mode (the oil pump starts, the motor reverses, and the system returns oil to the tank normally. For the specific principle, see the oil circuit conversion system). When the vehicle is not in the above three modes at the same time, it is judged whether the vehicle is in neutral gear. If the vehicle is in neutral gear and the speed is judged to be zero, the handbrake is pulled, the motor is turned off, and the on / off switch valve is closed, and the vehicle driving ends. If the vehicle is judged to be in neutral gear but the vehicle speed is not zero, it returns to the vehicle forward gear judgment stage and enters the next logic judgment cycle.

[0127] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features, and in the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0128] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0129] 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 above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0130] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0131] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A vehicle driving system, characterized in that: Including oil tank, hydraulic pump, hydraulic motor, reducer and axle; The hydraulic pump is connected to the oil tank and the hydraulic motor respectively, and is used to supply hydraulic oil to the hydraulic motor for driving the hydraulic motor to rotate; The hydraulic motor is connected to the axle via a reducer to provide power to the axle; The oil outlet of the hydraulic motor is provided with a load component having a preset pressure; When the vehicle is in the driving braking process, when the rotating wheels pull the hydraulic motor back, the oil at the motor outlet converts the vehicle's kinetic energy during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

2. The vehicle driving system according to claim 1, characterized in that: The load component is a relief valve; one end of the relief valve is connected to the oil outlet of the hydraulic motor, and the other end is connected to the oil tank or the oil inlet of the hydraulic motor.

3. The vehicle driving system according to claim 2, characterized in that: The relief valve is connected to the oil outlet of the hydraulic motor through a load cartridge valve; The oil inlet of the load cartridge valve is connected to the oil outlet of the hydraulic motor, the oil outlet of the load cartridge valve is connected to the oil tank, and the control port of the load cartridge valve is connected to the oil inlet of the relief valve; The load cartridge valve is used for conducting only when the pressure of the motor oil outlet is greater than or equal to the pressure set by the relief valve, and the pressure oil at the motor oil outlet will flow back to the oil tank.

4. The vehicle driving system according to claim 1, characterized in that: The load component is an accumulator; the accumulator is connected to the oil outlet of the hydraulic motor and is used to store pressurized oil.

5. The vehicle travel system according to claim 1, characterized in that: The vehicle travel system also includes an oil circuit switching system; The oil circuit switching system is connected to the oil inlet and oil outlet of the hydraulic pump, and the oil inlet and oil return port of the hydraulic motor respectively, and is used to switch the running direction of the hydraulic motor.

6. The vehicle travel system according to claim 5, characterized in that: The oil circuit switching system includes a controller, a first cartridge valve, a second cartridge valve, a third cartridge valve, a fourth cartridge valve, a three-position four-way reversing valve, a first two-position three-way reversing valve, and a second two-position three-way reversing valve; The P port of the three-position four-way reversing valve is connected to the outlet of the first two-position three-way reversing valve, the T port is connected to the oil tank, the A port is respectively connected to the third cartridge valve control port, the first cartridge valve control port and the A port of the second two-position three-way reversing valve, the B port is respectively connected to the fourth cartridge valve control port and the B port of the second two-position three-way reversing valve, and the three-position four-way reversing valve is controlled by the controller to switch the running direction of the hydraulic motor; The first two-position three-way reversing valve is connected to the oil outlet P of the hydraulic pump, the oil outlet B of the hydraulic motor and the P port of the three-position four-way reversing valve respectively, and is controlled by the controller to connect the P port of the three-position four-way reversing valve with the oil outlet P of the hydraulic pump or the oil outlet B of the hydraulic motor respectively, thereby changing the connection state of the P port of the three-position four-way reversing valve; The second two-position three-way reversing valve is respectively connected to the A and B ports of the three-position four-way reversing valve and the control port of the second cartridge valve, and is controlled by the controller to respectively connect the control port of the second cartridge valve and the A port or the B port of the three-position four-way reversing valve, thereby changing the pressure of the control port of the second cartridge valve; The first cartridge valve is respectively connected to the hydraulic motor oil return port A, the three-position four-way reversing valve port A, and the hydraulic oil tank, and is also connected to the main oil circuits of the second cartridge valve and the fourth cartridge valve, and the control port is controlled by the liquid pressure of the three-position four-way reversing valve port A; The second cartridge valve is respectively connected to the hydraulic oil tank, the outlet of the second two-position three-way reversing valve, the hydraulic motor oil outlet B, and the inlet of the load cartridge valve, and is also connected to the main oil circuits of the first cartridge valve and the third cartridge valve, and the control port is controlled by the outlet liquid pressure of the second two-position three-way reversing valve; The third cartridge valve is respectively connected to the oil outlet PP of the hydraulic pump, the inlet of the load cartridge valve, the port A of the three-position four-way reversing valve, and the oil outlet B of the hydraulic motor, and is also connected to the main oil circuits of the second cartridge valve and the fourth cartridge valve, and the control port is controlled by the liquid pressure of the port A of the three-position four-way reversing valve; The fourth cartridge valve is respectively connected to the oil outlet P of the hydraulic pump, the oil return port A of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is connected to the main oil circuit of the second cartridge valve and the fourth cartridge valve. The control port is controlled by the liquid pressure of the B port of the three-position four-way reversing valve.

7. The vehicle driving system according to claim 6, characterized in that: When the vehicle is in forward mode, the controller controls the left side of the three-position four-way reversing valve to connect, port T is connected to port B, port P is connected to port A, The controller controls the first two-position three-way reversing valve and the second two-position three-way reversing valve to be in a power-off state. The first two-position three-way reversing valve is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve respectively; The second two-position three-way reversing valve is respectively connected to the B port of the three-position four-way reversing valve and the control port of the second cartridge valve; High-pressure oil enters the first cartridge valve and the third cartridge valve, the main valve core is closed, the first cartridge valve and the third cartridge valve are in the cut-off state, and the cartridge valves and are in the connected state; the hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, passes through the fourth cartridge valve, enters from the hydraulic motor oil return port A, flows out from the hydraulic motor oil outlet B, and finally flows back to the oil tank through the second cartridge valve; in this process, the hydraulic motor rotates forward to drive the vehicle forward; When the vehicle is in the reverse mode, the controller controls the right path of the three-position four-way reversing valve to be connected, the T port is connected to the A port, and the P port is connected to the B port; The controller controls the first two-position three-way reversing valve and the second two-position three-way reversing valve to be in a power-off state. The first two-position three-way reversing valve is connected to the oil outlet P of the hydraulic pump and the P port of the three-position four-way reversing valve respectively; The second two-position three-way reversing valve is respectively connected to the B port of the three-position four-way reversing valve and the control port of the second cartridge valve; The high-pressure oil enters the second cartridge valve and the fourth cartridge valve, the main valve core is closed, the second cartridge valve and the fourth cartridge valve are in a cut-off state, and the first cartridge valve and the third cartridge valve are in a connected state; The hydraulic oil flows from the hydraulic pump to the hydraulic pump outlet P, enters from the hydraulic motor outlet B through the third cartridge valve, flows out from the hydraulic motor return port A, and finally flows back to the tank through the first cartridge valve; During this process, the hydraulic motor reverses to drive the vehicle backward; When the vehicle enters the forward braking mode, the controller controls the left path of the three-position four-way reversing valve, the T port is connected to the B port, and the P port is connected to the A port; The first two-position three-way reversing valve and the second two-position three-way reversing valve are switched from a de-energized state to an energized state; The first two-position three-way reversing valve is connected to the hydraulic motor oil outlet B and the three-position four-way reversing valve P respectively; the pilot oil for controlling the first cartridge valve and the third cartridge valve is changed from being provided at the pump outlet pipeline to being provided at the motor return oil pipeline, so that the cut-off pressure of the cartridge valve becomes higher; The second two-position three-way reversing valve is respectively connected to the A port of the three-position four-way reversing valve and the control port of the second cartridge valve; The cut-off pressure of the cartridge valve is made the same as that of the first cartridge valve and the third cartridge valve, and the second cartridge valve is in a cut-off state; The high-pressure oil acts on the first cartridge valve, the second cartridge valve, and the third cartridge valve, the main valve core is closed, the first cartridge valve, the second cartridge valve, and the third cartridge valve are in a cut-off state, and the fourth cartridge valve is in a connected state; The hydraulic oil flows from the hydraulic pump to the hydraulic pump outlet P, enters from the hydraulic motor return port A through the fourth cartridge valve, and flows out from the hydraulic motor outlet B; at this time, the other three cartridge valves are in the cut-off state, and the motor return oil can only flow back to the tank from the load cartridge valve; The load cartridge valve and the relief valve control the return oil pressure of the pipeline. When the motor return oil pipeline pressure is lower than the set pressure of the relief valve, the hydraulic motor only takes in oil but does not discharge oil. The motor oil outlet pressure rises until it is higher than the set pressure of the relief valve. Only when the motor return oil pipeline pressure is higher than the set pressure of the relief valve, can the motor return oil flow back to the tank.

8. The vehicle driving system according to claim 5, characterized in that: The oil circuit switching system includes a first hydraulically controlled one-way valve, a second hydraulically controlled one-way valve, a third hydraulically controlled one-way valve, a fourth hydraulically controlled one-way valve, a fifth hydraulically controlled one-way valve, a three-position four-way reversing valve, and a two-position one-way reversing valve; The P port of the three-position four-way reversing valve is connected to the oil outlet P of the hydraulic pump, the T port is connected to the oil tank, the A port is connected to the control port of the third hydraulically controlled one-way valve and the two-position one-way reversing valve, and the B port is connected to the control ports of the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The three-position four-way reversing valve is controlled by the controller and is used to switch the running direction of the hydraulic motor; The two-position one-way reversing valve is connected to the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve, and is controlled by the controller to unidirectionally conduct or bidirectionally conduct the A port of the three-position four-way reversing valve and the second hydraulically controlled one-way valve, thereby changing the pressure of the control port of the second hydraulically controlled one-way valve; The first hydraulically controlled one-way valve is respectively connected to the hydraulic motor oil return port A, the hydraulic oil tank, and the three-position four-way reversing valve port B, and is also connected to the second hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The first hydraulically controlled one-way valve is controlled by the pressure of the three-position four-way reversing valve port B. The second hydraulically controlled one-way valve is respectively connected to the two-position one-way reversing valve, the oil inlet of the load cartridge valve, the oil outlet B of the hydraulic motor, and the hydraulic oil tank, and is also connected to the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve. The second hydraulically controlled one-way valve is controlled by the outlet pressure of the two-position one-way reversing valve. The third hydraulically controlled one-way valve is respectively connected to the oil return port A of the hydraulic motor, the oil outlet port P of the hydraulic pump, and the port A of the three-position four-way reversing valve, and is also connected to the first hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The third hydraulically controlled one-way valve is controlled by the pressure of the port A of the three-position four-way reversing valve. The fourth hydraulically controlled one-way valve is respectively connected to the oil inlet of the load cartridge valve, the oil outlet B of the hydraulic motor, and the B port of the three-position four-way reversing valve, and is also connected to the second hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve. The fourth hydraulically controlled one-way valve is controlled by the outlet pressure of the B port of the three-position four-way reversing valve; The fifth hydraulically controlled one-way valve is connected to the oil outlet P of the hydraulic pump, the third hydraulically controlled one-way valve, and the fourth hydraulically controlled one-way valve respectively, and the control port is not connected to the pipeline, and is used for unidirectionally conducting the fourth hydraulically controlled one-way valve and the oil outlet P of the hydraulic pump.

9. The vehicle driving system according to claim 8, characterized in that: When the vehicle enters the forward mode, the left path of the three-position four-way reversing valve is connected, the T port is connected to the B port, and the P port is connected to the A port; The controller controls the two-position one-way directional valve to be in a power-off state, and conducts the A port of the three-position four-way directional valve and the control port of the second hydraulically controlled one-way valve; The pilot oil is introduced at the hydraulic pump outlet P to control different hydraulically controlled check valves through the three-position four-way reversing valve; The pilot oil enters the control ports of the second hydraulically controlled one-way valve and the third hydraulically controlled one-way valve, and the main valve core opens and is in a connected state; The hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, enters from the oil return port A of the hydraulic motor through the third hydraulically controlled one-way valve, flows out from the oil outlet B of the hydraulic motor, and finally flows back to the oil tank through the second hydraulically controlled one-way valve; during this process, the hydraulic motor rotates forward to drive the vehicle forward; When the vehicle enters the reverse mode, the controller controls the right path of the three-position four-way reversing valve to be connected, the T port is connected to the A port, and the P port is connected to the B port; The controller controls the two-position one-way directional valve to be in a power-off state, and conducts the A port of the three-position four-way directional valve and the control port of the second hydraulically controlled one-way valve; Pilot oil is introduced at the oil outlet of the hydraulic pump to control different hydraulically controlled check valves through a three-position four-way reversing valve; The pilot oil enters the control ports of the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve, so that the main valve core is opened, and the first hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve are in a connected state; The hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, enters from the oil outlet B of the hydraulic motor through the fourth hydraulically controlled one-way valve and the fifth hydraulically controlled one-way valve, flows out from the oil return port A of the hydraulic motor, and finally flows back to the oil tank through the first hydraulically controlled one-way valve; during this process, the hydraulic motor reverses to drive the vehicle backward; When the vehicle is in forward braking mode, the controller controls the three-position four-way reversing valve to the left position, the T port is connected to the B port, and the P port is connected to the A port; The two-position one-way directional control valve is converted from the de-energized state to the energized state, and the oil path from the A port of the three-position four-way directional control valve to the control port of the second hydraulically controlled one-way valve is unidirectionally closed, so that the control port of the second hydraulically controlled one-way valve has no control pressure; The pilot oil enters the control port of the third hydraulically controlled one-way valve, the main valve core opens, and the third hydraulically controlled one-way valve is in a connected state; The hydraulic oil flows from the hydraulic pump to the oil outlet P of the hydraulic pump, enters from the hydraulic motor return port A through the third hydraulically controlled one-way valve, and flows out from the hydraulic motor outlet B. The motor return oil can only flow back to the oil tank from the load cartridge valve. The load cartridge valve and the relief valve control the pipeline return oil pressure. Only when the motor return oil pipeline pressure is greater than the set pressure of the relief valve, can the motor return oil flow back to the oil tank.

10. A method for controlling a vehicle driving system, characterized in that: The vehicle driving system according to any one of claims 1 to 9 comprises the following steps: When the vehicle is in forward braking mode, a load component with a preset pressure is connected to the oil outlet of the hydraulic motor, so that the motor outlet oil converts the vehicle's kinetic energy during driving into heat energy or pressure potential energy through the load component to perform deceleration braking.

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