WO2017101034A1

WO2017101034A1 - Dual-power drive system, engineering machinery vehicle, and control method

Info

Publication number: WO2017101034A1
Application number: PCT/CN2015/097528
Authority: WO
Inventors: 单增海; 丁宏刚; 孙建华; 李丽; 朱磊
Original assignee: 徐州重型机械有限公司
Priority date: 2015-12-16
Filing date: 2015-12-16
Publication date: 2017-06-22

Abstract

A dual-power drive system, comprising a mechanical power drive subsystem and a hydraulic power drive subsystem which are respectively used for driving different axles, wherein when both power drive subsystems are enabled, the off-ground rotation speed of a wheel corresponding to the mechanical power drive subsystem is controlled not to be higher than the off-ground rotation speed of a wheel corresponding to the hydraulic power drive subsystem. The hydraulic power drive subsystem comprises: a hydraulic motor (6); a hydraulic pump mechanism; an on-off mechanism provided on a hydraulic circuit between the hydraulic pump mechanism and the hydraulic motor (6) for enabling or disabling the hydraulic oil supply to the hydraulic motor (6) by the hydraulic pump mechanism; and an overflow mechanism provided at an inlet of the hydraulic motor (6) for implementing an overflowing function of excess hydraulic oil at the inlet position of the hydraulic motor (6). Also provided are an engineering machinery vehicle comprising the dual-power drive system and a control method for the dual-power drive system. The dual-power drive system is capable of supplying drive power when non-rigid connection is utilized between axles driven by different power drive systems.

Description

Dual power drive system, construction machinery vehicle and control method

Technical field

The invention relates to a vehicle driving technology, in particular to a dual power driving system and a control method.

Background technique

Construction machinery vehicles are widely used in heavy-duty transportation, construction, field hoisting and public services. The construction environment is usually harsh, the road surface is uneven, and the road conditions are poor. Therefore, the driving performance of construction machinery vehicles has received increasing attention. For example, in the construction work of a wheeled crane, it is often necessary to transfer back and forth between the various construction sites. In the process of moving, it is often necessary to carry a large load or wading in the mountains, so the driving performance requirements are relatively high.

The existing construction machinery vehicles are mostly single power system driving modes. As shown in the mechanical power driving system shown in Fig. 1, the engine a1 provides power to the axle through the gearbox a2, the transfer case a3 and the transmission shaft a4. The power drive system is mainly applied to construction machinery vehicles that are driving on highways, and has high transmission efficiency and large speed range. For low-speed, high-torque, and off-highway construction machinery vehicles that often travel on the construction site, such as loader powertrain, excavator travel systems, and crawler crane travel systems, etc., The hydraulic power drive system, that is, the engine b1 drives the pump b2 to supply the hydraulic oil to the motor b3, and the motor b3 is connected with the drive axle b4 to provide driving power. The hydraulic power drive system has good stepless speed regulation performance and layout flexibility. However, its speed range is small and its efficiency is low, so it is less used on roads.

For multi-level axle construction machinery vehicles, there has been a dual-power drive system combining mechanical power drive and hydraulic power drive for more severe road conditions or climbing requirements, but such dual power The drive system is in use In the past, the phenomenon that the wheel speed of the mechanical power drive is inconsistent with the wheel speed of the hydraulic power drive, and the inconsistent speed may cause the problem that the power of the whole machine cannot be effectively improved or the wheel wear is prone to occur. In order to solve this problem, Usually, the axles corresponding to different power drives are rigidly connected through the transmission shaft, so that the rotational speeds are forced to be the same, but this will limit the transmission design of the axle, and also cause power switching difficulties.

Summary of the invention

The object of the present invention is to provide a dual power drive system, a construction machine vehicle and a control method capable of providing drive power in the case of a non-rigid connection between axles driven by different power drive systems.

To achieve the above object, the present invention provides a dual power drive system including a mechanical power drive subsystem and a hydraulic power drive subsystem for driving different axles, respectively, wherein the mechanical power drive subsystem and hydraulic power are When the driving subsystem is enabled, the wheel ground speed of the axle driven by the mechanical power driving subsystem is not higher than the wheel ground speed of the axle driven by the hydraulic power driving subsystem; the hydraulic power driving subsystem is specific include:

a hydraulic motor for providing driving power to the axle;

a hydraulic pump mechanism for supplying hydraulic oil for driving the hydraulic motor to the hydraulic motor;

An on-off mechanism, disposed on a hydraulic oil circuit between the hydraulic pump mechanism and the hydraulic motor, for connecting or disconnecting a hydraulic oil supply of the hydraulic pump to the hydraulic motor;

An overflow mechanism is provided at the inlet of the hydraulic motor for achieving an overflow function of excess hydraulic oil at an inlet position of the hydraulic motor.

Further, the on-off mechanism includes a first cartridge valve, an inlet port and an outlet port of the first cartridge valve respectively and an outlet of the hydraulic pump mechanism and the hydraulic motor The inlet of the first cartridge valve receives the pressure control signal, and opens or closes the internal oil passage between the oil inlet port and the oil outlet port of the first cartridge valve according to the pressure control signal.

Further, the on-off system further includes a reversing valve, wherein the two working ports of the reversing valve respectively communicate with the control port of the first cartridge valve and the return oil passage, and the reversing valve advances The oil port and the oil return port are respectively connected to the outlet of the hydraulic pump mechanism and the oil return oil passage, and an orifice is provided on the control port of the first cartridge valve, and the first is realized by switching of the reversing valve The cartridge valve is opened or closed.

Further, the overflow mechanism includes a first relief valve, and an inlet and an outlet of the first relief valve are respectively connected to an inlet and a return oil passage of the hydraulic motor, and the first relief valve is adjusted The set pressure is higher than the system pressure of the hydraulic motor at maximum torque.

Further, the overflow mechanism includes a second relief valve and a second cartridge valve, and an inlet and an outlet of the second cartridge valve are respectively connected to an inlet of the hydraulic motor and a return oil passage, the overflow The inlet and the outlet of the flow valve are respectively connected with the control port and the return oil passage of the second cartridge valve, and an orifice for connecting the inlet and the control port is arranged in the valve core of the second cartridge valve. The set pressure of the second relief valve is higher than the system pressure of the hydraulic motor at the maximum torque.

Further, a check valve for preventing backflow of the hydraulic oil is provided at an outlet of the hydraulic pump mechanism.

Further, the hydraulic motor is a bidirectional hydraulic motor, and the on/off mechanism is an electromagnetic reversing valve, and the two working ports of the electromagnetic reversing valve are respectively connected to the oil ports at both ends of the bidirectional hydraulic motor, and are switched by The electromagnetic reversing valve is capable of changing an inlet of the two-way hydraulic motor, the overflow mechanism including a third relief valve and a fourth relief valve respectively disposed at two end ports of the bidirectional hydraulic motor, The oil ports of the two-way hydraulic motor are used as the overflow function of the excess hydraulic oil at the time of inlet.

Further, the hydraulic pump mechanism includes a metering pump and a third relief valve, The metering pump outputs a constant flow of hydraulic oil, and controls the output flow of the metering pump to always exceed the required flow rate of the hydraulic motor, the inlet and outlet of the third relief valve and the outlet and back of the metering pump, respectively The oil passage is in communication for overflowing the outlet of the metering pump such that hydraulic oil flowing to the hydraulic motor conforms to a desired flow rate of the hydraulic motor.

Further, the hydraulic pump mechanism is a constant pressure variable pump capable of adaptively adjusting the output flow rate to match the required flow rate of the hydraulic motor.

To achieve the above object, the present invention also provides a construction machine vehicle comprising the aforementioned dual power drive system.

To achieve the above object, the present invention also provides a control method based on the foregoing dual power drive system, comprising:

When receiving the dual power drive mode operation command, the control on/off mechanism connects the hydraulic pump mechanism to the hydraulic motor supply of the hydraulic motor, and activates the hydraulic power drive subsystem to enable the mechanical power drive subsystem and the hydraulic power drive subsystem to be enabled. a dual power drive mode in which the wheel ground speed of the axle driven by the mechanical power drive subsystem is controlled to be no higher than the wheel ground speed of the axle driven by the hydraulic power drive subsystem;

Controlling the on/off mechanism to disconnect the hydraulic oil supply of the hydraulic motor to the hydraulic motor when the pure mechanical power drive mode operation command is received, and stopping the activation of the hydraulic power drive subsystem to achieve a pure mechanical power drive mode .

Further, in the dual power driving mode, the method further includes: adjusting a magnitude of driving power provided by the hydraulic motor to the axle according to a required vehicle speed.

Further, in the purely mechanical power driving mode, the method further comprises: determining whether the hydraulic motor is connected to the axle according to the speed measurement result of the hydraulic motor, and if yes, issuing a shutdown prompt.

Further, a pressure sensor is disposed at an outlet of the hydraulic pump mechanism for detecting a system pressure when the hydraulic power drive subsystem is working, in the dual power In the driving mode, the method further includes: determining whether the hydraulic power driving subsystem is abnormal according to the fluctuation of the system pressure, and if the abnormality is determined, decelerating the shutdown.

Based on the above technical solution, when the mechanical power drive subsystem and the hydraulic power drive subsystem are simultaneously activated, the wheel speed of the axle of the axle driven by the mechanical power drive subsystem is controlled to be no higher than the hydraulic power drive. The wheel speed of the axle driven by the subsystem is off-ground, and the wheel speed driven by the hydraulic power is determined by the hydraulic system flow. When the double-drive axle is grounded, the hydraulic power-driven wheel speed is not slipped. The mechanically driven wheels rotate at the same speed, which in turn reduces the hydraulic flow required by the hydraulic motor. The hydraulic pump supplies the hydraulic motor with the corresponding flow of hydraulic oil to maintain the same wheel speed. When encountering the unfavorable situation of system impact or climbing and rolling, the overflow mechanism at the inlet of the hydraulic motor can discharge excess hydraulic oil in the hydraulic system oil passage in time to avoid damage to the hydraulic system.

DRAWINGS

1 is a schematic structural view of an example of a conventional mechanical power drive system.

2 is a schematic structural view of an example of a conventional hydraulic power drive system.

Figure 3 is a schematic diagram of wheel speed and force analysis of a dual power drive system.

4 is a schematic view showing the hydraulic principle of a hydraulic power drive subsystem in an embodiment of the dual power drive system of the present invention.

FIG. 5 is a schematic view showing the hydraulic principle of a hydraulic power drive subsystem in another embodiment of the dual power drive system of the present invention.

6 is a schematic view showing the hydraulic principle of a hydraulic power drive subsystem in still another embodiment of the dual power drive system of the present invention.

detailed description

The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments.

When the mechanical power drive and the hydraulic power drive drive the partial axles respectively, the two-power drive system has inconsistencies in the rotational speed of the wheels from the ground. As shown in Fig. 3, it is assumed that the rotational speed of the wheels driven by the mechanical power is n1, and the hydraulic power is driven. The wheel rotates at a speed of n2. When n1>n2, the hydraulically driven wheels will be dragged by the mechanically driven wheels during the running of the vehicle, generating a resistance F3, so that the hydraulic power system cannot improve the power of the vehicle. effect.

On the other hand, when n1 < n2, the hydraulically driven wheel always provides the power of F2 during the running of the vehicle, but when the ground of the hydraulically driven wheel is wet or sagged, the wheel will wear and wear. It can be seen that the hydraulically driven wheels can provide both power and wheel wear only when the wheels are at the same speed n1 and n2 from the ground. According to the mechanical theory, to realize the same n1 and n2, the corresponding two axles must be connected through the transmission shaft, that is, the rigid connection between the two axles must be made, but this will limit the transmission design of the axle. It also causes power switching difficulties, and different power sources for rigid connections are difficult to match.

In order to overcome this limitation, to achieve effective driving of the axle under different power drive systems of non-rigid connection, the present invention controls the way to make the wheel speed of the axle driven by different power drive systems the same when the vehicle is running, in order to achieve this It is claimed that the dual power drive system of the present invention includes a mechanical power drive subsystem and a hydraulic power drive subsystem for driving different axles, respectively. The hydraulic power drive subsystem specifically includes: a hydraulic motor 6, a hydraulic pump mechanism, an on-off mechanism and an overflow mechanism, and the hydraulic motor 6 is connected to the corresponding axle, and provides driving power to the axle by converting hydraulic energy into torque. The hydraulic pump mechanism draws in hydraulic oil from the hydraulic oil tank, and supplies the hydraulic motor 6 with hydraulic oil that drives the hydraulic motor 6 to rotate.

The on-off mechanism is disposed on the hydraulic oil circuit between the hydraulic pump mechanism and the hydraulic motor 6, and is responsible for accessing or disconnecting the hydraulic oil supply of the hydraulic pump 6 to the hydraulic motor 6, and the user can control the on-off mechanism according to different road conditions. It is possible to realize whether the hydraulic power drive subsystem is connected to the power supply of the vehicle to realize the hydraulic power, thereby realizing There are many modes of power driving, such as pure mechanical power drive or dual power simultaneous drive.

The overflow mechanism is provided at the inlet of the hydraulic motor 6, and is responsible for achieving the overflow function of excess hydraulic oil at the inlet position of the hydraulic motor 6. When the hydraulic motor reverses when the engineering vehicle is rolling or reversing, the inlet pressure of the hydraulic motor 6 exceeds the system set pressure, and the hydraulic flow that cannot enter the hydraulic motor 6 can be flowed back to the hydraulic tank through the overflow mechanism, thereby being eliminated in time. Avoid hydraulic oil damage to the piping or hydraulic components of the hydraulic power drive subsystem.

Under the hydraulic power drive subsystem, the present invention further controls the wheel ground speed n1 of the axle driven by the mechanical power drive subsystem to be no higher than when the mechanical power drive subsystem and the hydraulic power drive subsystem are both activated. The wheel of the axle driven by the hydraulic power drive subsystem is off-ground speed n2.

According to the hydraulic theory, the wheel speed is determined by the hydraulic system flow. The system flow Q2 required for the wheel ground speed n2 and the system flow rate Q1 when the vehicle is grounded at the speed n1 are simultaneously activated when the dual power drive subsystem is activated. When the wheel speed is the same (except for wheel slip), and the hydraulically driven wheels only need to provide Q1 flow when n1≤n2, then for the fixed pump with overflow valve, the excess (Q2-Q1) The flow will flow back to the hydraulic tank through the relief valve.

Since the flow rate of (Q2-Q1) will flow back to the hydraulic tank through the relief valve, the system pressure is maintained constant at the maximum Pmax, so that the hydraulically driven wheels always provide the maximum driving force, and the wheel speed and the mechanically driven wheel speed The same goal. After the vehicle wheel is grounded, since the hydraulically driven wheel speed is the same as the mechanically driven wheel speed, that is, the hydraulic wheel speed is limited, the power provided by the hydraulic drive is a kind of ground load, driving speed, and flat road slope. The driving force is always the largest regardless of the driving force such as the working condition. It is not affected by other system factors, and the hydraulic drive wheel slips only after the local surface adhesion coefficient decreases. In other words, the present invention makes it possible to adjust the existing hydraulic drive power depending on the vehicle load or the travel speed. The switch is only dependent on the mechanically driven wheel speed. As long as the mechanically driven wheel speed is less than the hydraulically driven wheel speed, the power provided by the hydraulic drive will always provide the maximum driving force without slipping. For medium and high speed conditions, the displacement of the hydraulic motor can also meet the same requirements for the wheel speed under non-maximum driving force and the mechanically driven wheel speed.

In the hydraulic schematic diagram of the hydraulic power drive subsystem of the two dual power drive system embodiments shown in FIGS. 4 and 5, the on/off mechanism may include a first cartridge valve 2, the oil of the first cartridge valve 2 The port and the oil outlet are respectively connected with the outlet of the hydraulic pump mechanism and the inlet of the hydraulic motor 6, the control port of the first cartridge valve 2 receives the pressure control signal, and opens or closes the first cartridge valve 2 according to the pressure control signal. The internal oil passage between the oil inlet and the oil outlet. The pressure control signal can be realized by a module for supplying pilot oil (for example, an external pilot oil pump, etc.), or can be provided by the hydraulic pump mechanism itself, that is, the reversing valve 3 is added in the on-off system, and the two working ports of the reversing valve 3 are respectively The control port of the first cartridge valve 2 and the return oil passage 7 are connected, and the oil inlet port and the oil return port of the reversing valve 3 are respectively connected with the outlet of the hydraulic pump mechanism and the return oil passage 7 respectively, taking into account the outlet of the hydraulic pump mechanism The pressure is higher than the oil pressure requirement of the control port of the first cartridge valve 2, so that an orifice can be provided on the control port of the first cartridge valve 2 to reduce the oil pressure from the hydraulic pump mechanism. In another embodiment, the on-off mechanism may also employ a hydraulic directional valve instead of a cartridge valve.

As shown in FIG. 4, the reversing valve 3 can adopt a two-position four-way electromagnetic reversing valve. When the reversing valve 3 is de-energized, the first cartridge valve 2 is in the right position, and the outlet pressure of the hydraulic pump mechanism is transmitted to The control port of the first cartridge valve 2 causes the first cartridge valve 2 to be closed, so that the hydraulic oil discharged from the hydraulic pump mechanism cannot enter the inlet of the hydraulic motor 6 through the first cartridge valve 2; when the reversing valve 3 is energized When the first cartridge valve 2 is in the left position, the control port of the first cartridge valve 2 communicates with the return oil passage 7 through the reversing valve 3, so that the pressure oil at the inlet of the first cartridge valve 2 can be overcome. The spring force of the first cartridge valve 2 pushes the spool to move toward the spring side, thereby opening the passage between the inlet and the outlet of the first cartridge valve 2 The road realizes the output of the hydraulic oil of the hydraulic motor 6 to the hydraulic motor 6 .

In the present embodiment, the cartridge valve is preferably used to realize the opening and closing of the oil passage between the hydraulic pump mechanism and the hydraulic motor, mainly considering that an ordinary on-off valve (such as an electromagnetic reversing valve, etc.) may not be able to satisfy the driving axle. The flow rate and pressure requirements of the hydraulic oil, and the cartridge valve can withstand the on-off requirements of the pressure line of higher pressure and flow.

The overflow mechanism is capable of discharging excess hydraulic oil in the present invention, and the implementation thereof preferably employs the overflow mechanism of FIG. 4 or FIG. 5, wherein the overflow mechanism of FIG. 4 includes a first relief valve 4, the relief valve The inlet and outlet are respectively in communication with the inlet and return oil passages 7 of the hydraulic motor 6, and the set pressure of the first relief valve 4 is higher than the system pressure of the hydraulic motor 6 at the maximum torque. As described above, for the case of system impact or hill-climbing, a large pressure is accumulated at the inlet of the hydraulic motor 6, and if the pressure is not released in time, the hydraulic power drive subsystem is further destroyed. The hydraulic circuit or component, if the check valve of the pump outlet is not provided, may also cause oil to flow back to the hydraulic pump mechanism and cause damage to the pump.

The overflow process of the relief valve also consumes system energy, causing problems with oil return heat. Therefore, the overflow mechanism shown in Figure 5 takes the form of a specific overflow + unloading, that is, the overflow mechanism includes a second relief valve 4' and a second cartridge valve 5, the inlet and the outlet of the second cartridge valve 5 are respectively connected to the inlet and return oil passages 7 of the hydraulic motor 6, and the inlet and outlet of the second relief valve 4' Corresponding to the control port of the second cartridge valve 5 and the return oil passage 7 respectively, an orifice for connecting the inlet and the control port is provided in the valve core of the second cartridge valve 5, and the second relief valve 5 is adjusted. The constant pressure is higher than the system pressure of the hydraulic motor 6 at the maximum torque.

When the inlet pressure of the hydraulic motor 6 reaches the set pressure of the second relief valve 5, the hydraulic oil there flows to the second relief valve 4' through the orifice in the spool of the second cartridge valve 5. The inlet is returned to the hydraulic oil tank via the second overflow valve 4'. At this time, due to the action of the orifice, a pressure difference between the inlet of the second cartridge valve 5 and the control port is generated, which can overcome the spring force. Opening the second cartridge valve 5 to open the second cartridge valve 5 The inlet and the outlet, so that the hydraulic oil at the inlet of the hydraulic motor 6 can be unloaded through the second cartridge valve 5, and the partially unloaded hydraulic oil does not require work, and therefore does not consume energy and generates heat. When the inlet pressure of the hydraulic motor 6 returns to normal, the second relief valve 4' is closed, the pressure difference between the inlet of the second cartridge valve 5 and the control port disappears, and the second cartridge valve 5 is closed by the spring force. Unloading channel. In order to meet the pressure difference requirements of the inlet and the control port, it is also possible to provide a throttle valve between the control port of the second cartridge valve 5 and the inlet of the second relief valve 4' depending on the situation.

In the selection of the hydraulic pump mechanism of the hydraulic power drive subsystem, a metering pump or a variable pump may be employed, wherein the embodiment of FIG. 4 shows a form of a hydraulic pump mechanism using a metering pump, wherein the hydraulic pump mechanism includes a metering pump 1 and The third relief valve 9, the inlet and the outlet of the third relief valve 9, are in communication with the outlet of the metering pump 1 and the return oil passage 7, respectively. The overflow value of the relief valve is the system pressure. According to the mechanical principle, the torque of the hydraulic power drive subsystem is F=F1*i0*i1, F1 is the output torque of the hydraulic motor, the speed ratio of the i0 reducer, and i1 is the speed ratio of the axle. When the speed ratio of the speed reducer and the speed ratio of the axle are constant values, the larger the output torque of the hydraulic motor 6, the larger the hydraulic driving force. The output torque of the hydraulic motor 6 is T=V*Δp*ηm/20π(Nm), and ηm is the mechanical efficiency of the motor. It can be seen that the output torque of the hydraulic motor 6 depends on the displacement of the motor and the pressure difference between the motor inlet and outlet. When a certain type of motor is selected, the displacement of the motor is constant, then only the pressure difference between the motor inlet and outlet ports affects the output torque of the motor.

When the dosing pump 1 is used to drive the hydraulic motor 6 to rotate, if the dosing pump 2 discharge flow rate is greater than the required flow rate of the hydraulic motor 6, then the system pressure is constant at the maximum pressure Pmax, and the excess flow is returned through the third relief valve 9. Hydraulic tank. By controlling the output flow rate of the dosing pump 1 to exceed the required flow rate of the hydraulic motor 6, the pressure difference between the inlet and outlet ports of the hydraulic motor 6 can be maintained at the maximum and constant, and the output torque of the hydraulic motor 6 is maximized and constant, that is, the same project. The power provided by the hydraulic power drive subsystem in the mechanical vehicle is always the largest and constant, which effectively improves the driving performance of the whole vehicle. When the switching mechanism is closed, the hydraulic oil output from the metering pump 2 will overflow through the third relief valve 9. Flow back to the hydraulic tank.

Fig. 5 shows an example in which a constant pressure variable pump 1' is employed as a hydraulic pump mechanism, and the constant pressure variable pump 1' can be adaptively adjusted by its own control mechanism in accordance with the demand of the hydraulic motor 6 in terms of output driving force and required flow rate. Output flow and maintain constant pressure to reduce or eliminate energy loss from system flooding. When the switching mechanism is closed, the constant pressure variable pump 1' can automatically adjust to the minimum output flow to reduce or avoid system overflow energy loss.

At the outlets of the various hydraulic pump mechanisms described above, a check valve 8 for preventing backflow of the hydraulic oil may be provided, thereby improving the safety of the hydraulic pump mechanism.

Considering the two-way driving requirement of the construction machinery vehicle, the hydraulic motor 6 can select a two-way hydraulic motor, as shown in FIG. 6, which is a schematic diagram of the hydraulic principle of the hydraulic power driving subsystem in another embodiment of the dual power driving system of the present invention. In this embodiment, the on-off mechanism is an electromagnetic reversing valve 11, and the two working ports of the electromagnetic reversing valve 11 are respectively connected to the oil ports at both ends of the bidirectional hydraulic motor, and the bidirectional hydraulic pressure can be changed by switching the electromagnetic reversing valve 11. The inlet of the motor, the overflow mechanism includes a third relief valve 12 and a fourth relief valve 13 respectively disposed at the oil ports at both ends of the bidirectional hydraulic motor, for realizing the excess of the ports of the bidirectional hydraulic motor as the inlet The overflow function of hydraulic oil. Thus, the driver of the construction machine vehicle can realize the forward or backward traveling request by controlling the position of the electromagnetic reversing valve 11. In addition, in the embodiment, the on-off mechanism can also implement switching by using a plurality of cartridge valves to accommodate the displacement requirement of the hydraulic motor, and the third relief valve 12 and the fourth relief valve in the overflow mechanism. 13 can also be replaced with a single-way overflow mechanism in the embodiment of Fig. 5, respectively. In the selection of the hydraulic pump mechanism, the present embodiment employs a constant pressure variable pump 1', and may be replaced with a combination of the fixed pump 1 and the third relief valve 9 as needed.

The embodiments of the above dual power drive system can be applied to various types of construction machinery vehicles, especially engineering machinery vehicles with heavy working conditions such as heavy load and hill climbing. The present invention can provide the required driving force for the construction machinery vehicle, and can Hydraulic drive The moving wheel speed is the same as the mechanically driven wheel speed.

Based on the above dual power drive system, the present invention also provides a corresponding control method, including:

When receiving the dual power drive mode operation command, the control on/off mechanism connects the hydraulic pump mechanism to the hydraulic motor supply of the hydraulic motor 6, and activates the hydraulic power drive subsystem to realize both the mechanical power drive subsystem and the hydraulic power drive subsystem. An activated dual power drive mode, in which the wheel ground speed of the axle driven by the mechanical power drive subsystem is not higher than the wheel ground speed of the axle driven by the hydraulic power drive subsystem;

When receiving the pure mechanical power drive mode operation command, the on/off mechanism is controlled to disconnect the hydraulic oil supply of the hydraulic motor 6 to the hydraulic motor 6, and the hydraulic power drive subsystem is stopped to realize pure mechanical power drive. mode.

Among them, the operator of the construction machinery vehicle can issue different driving mode operation commands to the controller by hand touching the button, for example, when driving on the road, because the road condition is better, the speed is faster, and the hydraulic power drive is not suitable at this time. Subsystems can use pure mechanical power drive mode, and when the operator thinks that the current road conditions are poor, such as low speed and high torque required for slope or heavy load transportation, you can choose dual power drive mode, using hydraulic pressure. The power drive subsystem provides drive assistance.

When the hydraulic power drive subsystem is connected, the maximum driving power that the hydraulic motor 6 provides to the axle can be selected according to the actual speed and torque demand, or the driving power of the axle portion can be provided, for example, the full torque is realized at a low speed. The driving power of the partial torque is realized at the medium and low speed.

Considering that when switching from the dual-power drive mode to the purely mechanical drive mode, if the hydraulic power drive subsystem is not actually disconnected due to a device failure or the like, the wheel driven by the hydraulic power may be slower than the mechanical speed. The wheel driven by the power is dragged to form a resistance, which reduces the running speed of the whole vehicle. Therefore, in the pure mechanical power driving mode, the speed measurement result of the hydraulic motor 6 can also be used. It is judged whether or not the hydraulic motor 6 is connected to the axle, and if so, a shutdown instruction is issued. If the rotational speed of the hydraulic motor 6 is 0, indicating that the hydraulic power drive subsystem has been normally disconnected, there is no need to perform any operation for the hydraulic power drive subsystem, and if the hydraulic motor 6 has a certain rotational speed, the hydraulic pump mechanism is still The hydraulic motor 6 is supplied with hydraulic oil for rotating, and it can be judged that the on-off mechanism is not working normally, and it is necessary to stop as soon as possible to perform adjustment, so that the operator can be notified to stop or directly stop.

In another embodiment, a pressure sensor 10 is disposed at an outlet of the hydraulic pump mechanism for detecting a system pressure when the hydraulic power drive subsystem is in operation, and in the dual power drive mode, the method further includes: The fluctuation of the system pressure determines whether the hydraulic power drive subsystem is working abnormally, and if it is abnormal, the vehicle is decelerated to stop.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

A dual power drive system includes a mechanical power drive subsystem and a hydraulic power drive subsystem for driving different axles, respectively, wherein when the mechanical power drive subsystem and the hydraulic power drive subsystem are both enabled, the control mechanism The wheel ground speed of the axle driven by the power drive subsystem is not higher than the wheel ground speed of the axle driven by the hydraulic power drive subsystem; the hydraulic power drive subsystem specifically includes:

a hydraulic motor (6) for providing driving power to the axle;

a hydraulic pump mechanism for supplying hydraulic oil for driving the hydraulic motor (6) to the hydraulic motor (6);

An on-off mechanism disposed on a hydraulic oil line between the hydraulic pump mechanism and the hydraulic motor (6) for accessing or disconnecting a hydraulic oil supply to the hydraulic motor (6) by the hydraulic pump mechanism ;

An overflow mechanism is provided at the inlet of the hydraulic motor (6) for effecting an overflow function of excess hydraulic oil at the inlet position of the hydraulic motor (6).
The dual power drive system according to claim 1, wherein said on/off mechanism comprises a first cartridge valve (2), and said oil inlet port and said oil outlet port of said first cartridge valve (2) are respectively said An outlet of the hydraulic pump mechanism is in communication with an inlet of the hydraulic motor (6), a control port of the first cartridge valve (2) receives a pressure control signal, and opens or closes the first cartridge valve according to a pressure control signal (2) The internal oil passage between the oil inlet and the oil outlet.
The dual power drive system of claim 2, wherein the on/off system further comprises a reversing valve (3), the two working ports of the reversing valve (3) respectively communicating with the first cartridge valve (2) a control port and a return oil passage (7), wherein the oil inlet port and the oil return port of the reversing valve (3) are respectively connected to the outlet of the hydraulic pump mechanism and the return oil passage (7), An orifice is arranged on the control port of the first cartridge valve (2), The opening or closing of the first cartridge valve (2) is achieved by switching of the reversing valve (3).
A dual power drive system according to any one of claims 1 to 3, wherein said overflow mechanism comprises a first relief valve (4), said inlet and outlet of said first relief valve (4) being respectively said The inlet of the hydraulic motor (6) is in communication with the return oil passage (7), and the set pressure of the first relief valve (4) is higher than the system pressure of the hydraulic motor (6) at the maximum torque.
A dual power drive system according to any one of claims 1 to 3, wherein said overflow mechanism comprises a second relief valve (4,) and a second cartridge valve (5), said second cartridge valve ( 5) an inlet and an outlet are respectively connected to an inlet and a return oil passage (7) of the hydraulic motor (6), and an inlet and an outlet of the second relief valve (4') and the second insert respectively The control port of the valve (5) is in communication with the return oil passage (7), and an orifice communicating with the inlet and the control port is provided in the spool of the second cartridge valve (5), the second overflow The set pressure of the valve (5) is higher than the system pressure of the hydraulic motor (6) at the maximum torque.
The dual power drive system according to claim 1, wherein a check valve (8) for preventing backflow of hydraulic oil is provided at an outlet of said hydraulic pump mechanism.
The dual power drive system according to claim 1, wherein said hydraulic motor (6) is a two-way hydraulic motor, said on/off mechanism is an electromagnetic reversing valve (11), and two of said electromagnetic reversing valves (11) The working oil ports are respectively connected to the oil ports at the two ends of the two-way hydraulic motor, and the inlet of the two-way hydraulic motor can be changed by switching the electromagnetic reversing valve (11), and the overflow mechanism comprises respectively disposed in the two-way The third relief valve (12) and the fourth relief valve (13) of the oil ports at both ends of the hydraulic motor are used to realize the overflow function of the excess hydraulic oil when the ports of the two-way hydraulic motor are respectively used as inlets.
A dual power drive system according to any one of claims 1 to 3, wherein said hydraulic pump mechanism comprises a metering pump (1) and a third relief valve (9), said metering pump (1) outputting a constant flow rate Hydraulic oil and control the loss of the metering pump (1) The outflow always exceeds the required flow rate of the hydraulic motor (6), and the inlet and outlet of the third relief valve (9) are respectively connected to the outlet of the metering pump (1) and the return oil passage (7) For overflowing the outlet of the metering pump (1) such that the hydraulic oil flowing to the hydraulic motor (6) meets the required flow rate of the hydraulic motor.
The dual power drive system according to any one of claims 1 to 3, wherein said hydraulic pump mechanism is a constant pressure variable pump (1') capable of adaptively adjusting an output flow rate to match said hydraulic motor (6). The required traffic.
A construction machine vehicle comprising the dual power drive system according to any one of claims 1 to 9.
A control method for a dual power drive system according to any one of claims 1 to 9, comprising:

When receiving the dual power drive mode operation command, the control on/off mechanism connects the hydraulic pump mechanism to the hydraulic motor supply of the hydraulic motor (6), and activates the hydraulic power drive subsystem to realize the mechanical power drive subsystem and the hydraulic power drive. a dual power driving mode in which the system is enabled, in which the wheel ground speed of the axle driven by the mechanical power drive subsystem is not higher than the wheel ground speed of the axle driven by the hydraulic power drive subsystem ;

When receiving the pure mechanical power drive mode operation command, controlling the on/off mechanism to disconnect the hydraulic oil supply of the hydraulic pump mechanism to the hydraulic motor (6), and stopping the activation of the hydraulic power drive subsystem to realize pure mechanical Power drive mode.
The control method according to claim 11, wherein in the dual power driving mode, further comprising: adjusting a magnitude of driving power supplied to the axle by the hydraulic motor (6) according to a required vehicle speed.
The control method according to claim 11, wherein in the purely mechanical power driving mode, further comprising: determining whether the hydraulic motor (6) is connected to the axle according to a speed measurement result of the hydraulic motor (6), If yes, a shutdown prompt is issued.
The control method according to claim 11, wherein a pressure sensor (10) is provided at an outlet of said hydraulic pump mechanism for detecting a system pressure when said hydraulic power drive subsystem operates, in said dual power drive mode The method further includes: determining whether the hydraulic power drive subsystem is abnormal according to the fluctuation of the system pressure, and if the abnormality is determined, decelerating the shutdown.