CN111806216A - A loader traveling hydrostatic and mechanical hybrid drive system - Google Patents

Abstract

A loader walking hydrostatic and mechanical hybrid driving system belongs to the field of engineering machinery and comprises a machine body, wherein a hydraulic system is arranged on the machine body; the hydraulic system comprises a hydraulic driving walking system and an oil tank; the mechanical system comprises a loader mechanical drive traveling system; the engine body is provided with an engine and a transfer case; the engine is connected with a transfer case, the transfer case is connected with a variable hydraulic pump, the variable hydraulic pump is connected with an oil inlet of a three-position three-way electromagnetic valve, one path of an oil outlet of the three-position three-way electromagnetic valve is connected with a hydraulic motor, a driving motor drives a load, and the other path of the oil outlet enters an energy accumulator through the three-position three-way electromagnetic valve to store energy. The hydraulic motor is connected with the planetary gear set, the torque is transmitted to the speed reducer after being changed in speed by the motor through the gear set, and then the loader is driven to run by the output shaft of the speed reducer. The invention not only reduces the actual service time of the hydraulic torque converter so as to improve the energy utilization efficiency of the system, but also improves the recovery of the braking kinetic energy of the loader by the hydraulic system.

Description

A loader traveling hydrostatic and mechanical hybrid drive system

technical field

The invention relates to a hydrostatic and mechanical hybrid drive system control system loader technology, in particular to a hydrostatic and mechanical hybrid drive system control system applied to loader walking, belonging to the technical field of scraper construction machinery vehicles.

Background technique

Loaders are used for loading, unloading, pushing and construction of bulk materials such as soil, gravel, coal, etc., and are widely used in various construction sites. Loaders in the prior art are divided into fuel-driven loaders and natural gas loaders, where the fuel oil loader is powered by an internal combustion engine such as a diesel engine, and the natural gas loader is powered by a gas-burning engine. At present, a large number of wheel loader transmission systems use internal combustion engine power, and the transmission device is hydraulic transmission, which is mainly composed of an engine, a torque converter, a power shift transmission, a drive shaft, and a drive axle. The power transmission system of this method is mature in technology, and the engine is generally dominated by diesel engines. The engine consumes a lot of fuel, wastes energy and pollutes the environment. The transmission efficiency of the torque converter is low, and the average efficiency is only about 30% in general work; the power shift transmission used in the loader is a multi-speed transmission, generally three forward gears, three gears backward or four forward gears backward. Four gears; the transmission is manually operated by hydraulic pressure, and the multi-plate friction clutch and brake are used for gear shifting. The structure is complex, the manufacturing cost is high, and the maintenance is difficult.

In the prior art, the Chinese patent discloses "a kind of power transmission device for pure electric loader (ZL201110278118.7)", although it realizes the transmission device that uses the electric motor or the battery pack instead of the internal combustion engine as the power, but does not fundamentally change the original. There is a mechanical transmission principle, and the advantages of motor transmission are not fully utilized.

The Chinese patent also discloses "electric control device for small loader (ZL201210551131.X)", which uses a motor to drive an electric cylinder, the electric cylinder drives a mechanical transmission mechanism, and the mechanical transmission mechanism finally drives the action mechanism and each working mechanism. The power provided by the motor and the mechanical transmission mechanism is small, and most of the loaders need a large power to drive, and the power of the electric-driven loaders in the prior art is relatively insufficient.

The performance of a loader's travel drive train has a significant impact on a loader's fuel economy, work efficiency, emissions, and reliability. The loader mainly includes bucket 18, front tire 5, front drive axle 10, front drive shaft 9, transmission 2, rear drive shaft 11, rear drive axle 12, rear tire 16, engine 1, rear counterweight 17, etc., fully hydraulic The hydraulic speed control transmission system of the walking loader has the advantages of a wide stepless speed control range, good starting characteristics and high transmission efficiency. It can optimize the engine working state according to the road surface and working conditions, so that the vehicle can obtain the best performance. Driving performance can meet the requirements of vehicle economy, power and comfort, and is an ideal form of walking transmission. At present, the loaders produced and used in large quantities in my country are all hydro-mechanical transmissions. This hydro-mechanical transmission system is mainly composed of an engine, a twin-turbo hydraulic transmission, front and rear drive shafts and a drive axle. The main disadvantages of this transmission system are: (1) The transmission efficiency of the torque converter is low, especially at low speeds (2) The forward and reverse reversing of the transmission relies on the friction clutch, which has a large shift impact and poor transmission reliability. (3) The twin-turbo torque converter has a one-way clutch, which has a complex structure and is prone to failure.

SUMMARY OF THE INVENTION

In order to solve the shortcomings of the traditional loader relying on mechanical transmission, the torque converter has low transmission efficiency, and the multi-plate friction clutch and brake shift have the disadvantages of complex structure, high manufacturing cost and difficult maintenance. The present invention provides a loader walking hydrostatic and mechanical hybrid drive system control system.

The utility model relates to a traveling hydrostatic and mechanical hybrid drive system of a loader, which is characterized in that: a transfer case outputs two branches to drive the traveling system under different working conditions. One is when the loader is loading and unloading materials, the transmission system works in the independent control system of the hydraulic system inlet and outlet, the hydraulic system working path is the hydraulic pump-three-position three-way solenoid valve-hydraulic pump/motor, and a part of the hydraulic oil enters the inlet of the motor. The oil port drives the motor to output torque, and another part of the hydraulic oil enters the accumulator for energy storage;

The gear at the output shaft end of the hydraulic pump/motor is meshed with the planetary gear mechanism, and the mechanical drive is formed by the planetary gear mechanism-gearbox-drive axle; the other one is in the mechanical transmission mode when the loader is in a long-distance transition operation. The output shaft of the transfer case is directly connected to the planetary gear mechanism, and is connected to the drive axle through the gearbox to drive the loader to walk.

The transfer case has one input port and two output ports; the two output ports are respectively connected to the variable hydraulic pump and the planetary gear mechanism.

The planetary gear mechanism: the external gear is fixed on the box body of the reduction box, the output shaft of the hydraulic motor is connected to the planetary gear, and the output shaft of the transfer case is connected to the sun gear.

The transfer case of the invention outputs two transmission routes. When the loader is transferred to a long-distance operation, the mechanical transmission system is used to drive the traveling mechanism to quickly reach the target position; when it is in the working state of loading and unloading materials, a variable pump-three-position three-way is used. Solenoid valve—the way of hydrostatic transmission of hydraulic motor, so as to match the output power of diesel engine with real-time external load.

The bladder-type accumulator used is a device used to store and release energy, and has the advantages of small size, light weight, and separation of oil and gas. The first aspect plays the role of storing and releasing energy. On the other hand, when the system is subjected to shock or instantaneous large load, resulting in a rapid increase in pressure in a short period of time, the accumulator can absorb this part of the energy, buffer and ensure that the system pressure is normal, and can make the hydraulic system Instruments, components and sealing devices are protected from pressure shock damage.

The present invention implements different working condition control for the loader walking, and adopts hydraulic and mechanical transmission respectively for shoveling, loading and unloading materials, and long-distance running of the field, which can not only reduce the actual use time of the hydraulic torque converter and improve the energy utilization efficiency of the system, but also The hydraulic system can be improved to recover the kinetic energy of the loader.

Description of drawings

Fig. 1 is the system principle diagram of the present invention;

In the figure, A is a three-position three-way solenoid valve, B is a three-position three-way solenoid valve, C is a two-position three-way solenoid valve, D is a three-position three-way solenoid valve, E is a reducer, and F is a transfer case. G is the engine.

Detailed ways

In this embodiment, a variable hydraulic pump is connected to the transfer case of the existing loader, and the variable hydraulic pump is respectively connected to the oil inlets of two three-position three-way solenoid valves (three-position three-way solenoid valve A, three-position three-way solenoid valve A, three-position three-way solenoid valve A, three-position three-way solenoid valve Solenoid valve B) and a 3/2-way solenoid valve (C).

The oil outlet of the three-position three-way solenoid valve A is connected to the hydraulic motor all the way to drive the motor to drive the load, and the oil outlet of the three-position three-way solenoid valve A enters the accumulator through the three-position three-way solenoid valve B to store energy.

The hydraulic motor is connected to the planetary gear set, and the torque is transmitted from the motor to the speed reducer after the gear set, and then the output shaft of the speed reducer drives the loader to walk.

Hydraulic drive path: The output end of the engine is connected to the transfer case, the output torque of the transfer case is given to the variable motor, and the variable motor draws hydraulic oil from the oil tank through the one-way valve. The hydraulic oil output by the variable pump is respectively transmitted to the three-position three-way solenoid valve A and the three-position three-way solenoid valve B, and is connected to the oil inlet of the two-position three-way solenoid valve at the same time.

When it is necessary to move forward, the three-position three-way solenoid valve B is in the upper position, and the three-position three-way solenoid valve A is in the lower position. The oil port on the hydraulic motor drives the motor to work forward, converts the hydraulic energy into mechanical energy to drive the loader forward, and the other way passes through the three-position three-way solenoid valve D to the accumulator to charge the accumulator;

During normal operation, the three-position three-way solenoid valve D is in the neutral position, and when the loader is in the braking state, the three-position three-way solenoid valve D is in the upper position, and the accumulator is charged;

When the loader starts, the accumulator moves to the oil inlet of the variable pump through the two-position three-way solenoid valve C to the right, and at the same time, the hydraulic motor oil outlet (lower end) returns to the upper position through the balance valve and the three-position three-way solenoid valve B. tank;

When it needs to retreat, the three-position three-way solenoid valve A is in the upper position, and the three-position three-way solenoid valve B is in the lower position. The lower oil port of the hydraulic motor drives the motor to work in reverse, converts the hydraulic energy into mechanical energy to drive the loader back, and the other way passes through the three-position three-way solenoid valve D to the lower position of the accumulator to charge the accumulator; during normal operation, The three-position three-way solenoid valve D is in the neutral position. When the loader is in the braking state, the three-position three-way solenoid valve D is in the upper position to charge the accumulator; when the loader starts, the accumulator passes through the two-position three-way solenoid valve D. Connect the solenoid valve C to the right position to the oil inlet of the variable pump, and at the same time, the hydraulic motor oil outlet (upper end) returns to the oil tank through the balance valve and the three-position three-way solenoid valve A.

The loader has the following working conditions: approaching the stockpile, digging materials, fully loaded back, forward unloading and empty back.

When the loader moves forward or backward normally, the loader is in the motor condition; when the loader is in full-load backward or no-load backward braking, the loader is in the hydraulic pump condition, and the three-position three-way solenoid valve D is at the right position, the kinetic energy recovery circuit is activated, and the kinetic energy of the loader is converted into the hydraulic energy in the high-pressure oil through the secondary element, and is stored in the high-pressure accumulator;

When the loader is approaching the stockpile or starts unloading, the three-position three-way solenoid valve D is in the left position, the recovery circuit is closed, and the two-position three-way valve is connected to the accumulator and the inlet of the hydraulic main pump. The high-pressure oil in the energy device flows into the oil inlet of the main pump, and the hydraulic energy is converted into the kinetic energy of the hydraulic pump to assist the loader to start. This process realizes the recovery and reuse of braking kinetic energy, which can effectively reduce the installed power and energy consumption of the hydraulic pump of the system.

Mechanical drive path: The output end of the engine is connected to the transfer case, the output torque of the transfer case is given to the planetary gear, and the planetary gear transmits the mechanical energy to the loader tire through the reducer to drive the loader forward or backward.

Claims (3)

1. a loader travels hydrostatic and mechanical hybrid drive system, comprising the transfer case of the loader, it is characterized in that the transfer case of the loader is connected with a variable hydraulic pump, and the variable hydraulic pump is connected with a three-position three-way valve A The oil inlet, the oil outlet of the three-position three-way solenoid valve A is connected to the hydraulic motor, and the drive motor drives the load. The port enters the accumulator to store energy; the hydraulic motor of the loader is connected to the planetary gear set, and the torque is transmitted from the motor to the reducer after the gear set, and then the output shaft of the reducer drives the loader to walk. 2. A loader traveling hydrostatic and mechanical hybrid drive system according to claim 1 is characterized in that when the loader is in a long-distance transition operation, the loader transmission system is in a mechanical transmission mode, and the transfer case output shaft directly Connect the planetary gear mechanism, connect to the drive axle through the gearbox, and drive the loader to walk. 3. The hydrostatic and mechanical hybrid drive system for a loader according to claim 1, characterized in that when the loader moves forward or backward normally, the loader is in the motor condition; When the load is reversed and braked, the loader is in the working condition of the hydraulic pump. At this time, the three-position three-way solenoid valve D is in the upper position, the kinetic energy recovery circuit is activated, and the loader braking kinetic energy is converted into the hydraulic energy in the high pressure oil through the secondary element, and stored into the high pressure accumulator; When the loader is approaching the stockpile or starts unloading, the three-position three-way solenoid valve D is in the lower position, the recovery circuit is closed, and the two-position three-way solenoid valve is connected to the accumulator and the inlet of the hydraulic main pump. The high-pressure oil in the energy device flows into the oil inlet of the main pump, and the hydraulic energy is converted into the kinetic energy of the hydraulic pump to assist the loader to start; this process realizes the recovery and reuse of the braking kinetic energy, which can effectively reduce the installed power and energy consumption of the hydraulic pump of the system. .

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