Forklift hydraulic control technology
Posted: Nov 22nd, '24, 02:15
As a kind of material handling and stacking machinery, forklifthas been deeply involved in all aspects of social life and production because of its flexible operation and convenient use. Today, the series and variety of forklifts are wide, according to different users, different working objects and different working environments can be roughly divided into the following 7 categories: 1, the seat electric forklift; 2, small electric stacker truck; 3, small electric carrier; 4, balanced weight solid tire internal combustion forklift; 5, balanced weight inflatable tire internal combustion forklift; 6, electric and internal combustion passenger trailer; 7, off-road forklift.
First, the working principle of forklift
Taking counterweight forklifts as an example, forkliftare generally divided into the following seven systems, namely power system (engine, motor), walking system (gearbox, torque converter, axle, driving wheel, etc.), braking system, electrical system, steering system, working device, and hydraulic system. The hydraulic system is an important part of the forklift, the working device and the steering system are driven by the hydraulic system. Therefore, the hydraulic system of forkliftdirectly affects the performance of forklift. A simple forklift hydraulic system is generally composed of power source (engine, motor) gear oil pump, high pressure oil pipe, multi-way valve, lifting cylinder, tilt cylinder, steering cylinder and some other control valves. The working principle is that the engine (motor) drives the hydraulic gear pump to continuously produce high pressure oil (gear pump principle is the same as the engine oil pump). The hydraulic oil is sucked out from the oil tank and enters the multi-way valve through the oil pipe. According to different working conditions, the operation handle can be pulled to realize the lifting, landing, forward leaning, backward leaning, and steering wheel steering. So as to achieve the forklift handling, loading and unloading of goods to meet people's requirements.
Two, forklift hydraulic system control examples
1. Hydraulic control system of all-electric stacker truck
Full hydraulic electric forklift hydraulic system is a new type of hydraulic control system independently developed by a company in China with patent rights. The working and control schematic diagram is as follows:
The hydraulic system mainly consists of the following areas: a working device composed of a lifting cylinder and a tilting cylinder; The steering system is composed of a steering device and a steering cylinder; The walking system is composed of a hydraulic motor and a hydraulic motor brake and a hydraulic motor speed regulating valve arranged on the hydraulic motor.
The working characteristics of the hydraulic system are that the three parts of the working device, the steering system and the walking system are driven by a motor to run a gear pump to obtain the required hydraulic energy to work. The hydraulic energy generated by the gear pump is output in two ways: one way is supplied to the steering device through the priority valve and the working device controlled by the multi-way valve to realize the lifting and lowering operation of the cargo fork; The other path leads through the pressure switching valve to the drive device controlled by the control valve and the reversing brake valve. This system replaces variable pump with gear pump, which is convenient to control the motor gear pump through the electrical system, and overcomes the defects of low efficiency, high energy consumption, high oil temperature and poor stability performance of hydraulic motor, walking and braking caused by long-term use.
2. Regenerative forklift hydraulic control system
Compared with the traditional forklift truck, the walking mechanism is two wheel type hydraulic motors, which can be conveniently installed in the corresponding position of the forklift chassis, saving the chassis space of the forklift truck. It is easy to arrange the door frame and reduce the weight of the forklift. By changing the direction of the oil through the reversing valve, the forklift can be made to move forward or backward, saving the driveway size of the warehouse and increasing the utilization rate of the stacking site. Compared with the traditional mechanical transmission, the full hydraulic transmission omits a set of complex reducer, differential, half shaft and other components, and the hydraulic system can be made into an integrated valve block, which makes the structure simple. The application range of the hydraulic system is large, 0.5-2.5 tons of all kinds of forklifts, even stacking tractors, trucks, etc., can be used, and can quickly introduce new varieties, which can greatly simplify the production process equipment of manufacturers. The hydraulic forkliftuses only one motor to drive the entire working device and walking mechanism, and the wave pump and motor are completely immersed in the oil to reduce noise, which is more concise and quiet than the traditional forklift truck.
3. Working process of hydraulic system
When the vehicle starts, the electric signal is sent out through the pedal, so that the motor drives the hydraulic pump to work. Because the motor adopts frequency conversion speed regulation, the non-working state is equivalent to the idle state. At this time, the motor power is only 10% of the rated working state. Hydraulic pump hydraulic oil into the reversing valve, through the reversing valve, the hydraulic oil into the hydraulic motor, drive the wheel rotation. When the reversing valve is in the middle position, the hydraulic oil flows back to the tank. With the reversing valve in the left or right position, complete the forkliftforward or backward. When the forklift truck slows down and stops without emergency braking, due to the inertia of the forklift truck, the wheel drives the hydraulic motor to rotate, so that the hydraulic motor becomes a hydraulic pump condition. A check valve is arranged on the suction line to prevent the pressure oil output by the hydraulic motor from flowing back to the tank and entering the hydraulic pump. The hydraulic pump rotates with the motor, at this time the hydraulic pump becomes a hydraulic motor, the motor becomes a generator, and the electricity emitted is quickly charged to the electric storage oil. When the forklift lifts the goods, the variable hydraulic pump is also driven by the motor. The variable hydraulic pump outputs the oil into the reversing valve. When the reversing valve is on the right, the oil directly enters the hydraulic cylinder to lift the heavy objects.
Third, compared with foreign forklift hydraulic system problems in our country To battery balance forklift truck as an example, the current domestic battery forklifttruck is in a relatively backward state, there are four main problems:
1, there is no energy recovery function, resulting in short working time of the forklift, more power consumption of the forklift, serious loss of the brake device and other problems.
2, the energy consumption is large, the current domestic forklift truck generally uses a quantitative hydraulic pump, adopt the throttling way to speed regulation.
3, the noise is relatively large, due to the defects of the motor and the wave pump used in the manufacturing process of the domestic forklift truck, the noise of the forklifttruck is much larger than that of foreign forklifts.
4, the structure size is large, most domestic battery forklift lifting, tilt and steering using hydraulic transmission, walking using mechanical transmission, resulting in a low power to volume ratio, the same tonnage of forkliftvolume is too large.
5, the failure rate is high, the quality stability of domestic hydraulic components is poor, the leakage phenomenon is serious.
In foreign countries, forklift hydraulic systems generally use stepless speed regulation and energy recovery, but most of them are limited to kinetic energy recovery; The power device of the hydraulic system, more use of variable frequency motor to drive the quantitative, variable hydraulic pump drive device, this device can achieve the purpose of energy saving: install a number of flow sensors and pressure gauges in the oil circuit, monitor the system, and through the installation of sensors for feedback, to achieve a high control accuracy.
Four, the development direction of hydraulic control on the forklift
1, energy saving and electromechanical hydraulic integration of high technology application
The development and application of microelectronics technology, sensing technology and information processing technology will improve the overall level of the forklift industry, achieve composite functions, and ensure the safety, control and automation level of the whole machine and system, so that the combination of electronics and machinery, electronics and hydraulics will be closer. The future development of forklifts lies in the application level of its electronic technology. For example, the Linde electric forward lift truck uses an inductive electronic steering system to provide variable torque feedback to the operator to ensure perfect control performance, requiring very little steering force. The realization of the microprocessor as the core of the electromechanical hydraulic integration is the main direction of the future development of forklift control system, that is, with the microprocessor as the core, the control from local control to the network direction, so that the vehicle to maintain a good working condition, to achieve the intelligent operation of forklift. Using electronic steering system and power steering ratio can save 25%, it can control the motor speed timely according to the working condition of forklift truck, which is an effective measure for energy saving and noise reduction of forklifttruck. In addition, MOSFET transistor than resistance speed regulation can save 20%, release regenerative braking can save 5-8%, the use of hydraulic motor controller and load potential energy recovery technology can save 20% and 5% respectively.
2, micro control pedal instead of the general forklift foot pedal
When operating a forklift truck, the driver often fails to grasp the strength of the foot carelessly, causing avoidable losses. The micro control pedal enables the driver to move precisely on the micro surface, which can better control the operation of the forklift and avoid various operational errors. The micro-motion control pedal can ensure the precise operation of the forklifttruck in the short-distance accurate positioning, especially in the large volume and quantity of the loaded goods, the good effect of the micro-motion control pedal is more obvious.
In short, at present, the use of advanced hydraulic control technology of forklifttrucks in China is less, the quality stability of hydraulic basic parts is poor, resulting in China's forklift trucks in the field of hydraulic control lags behind foreign countries, the technical added value of products is low, low international competitiveness and other status quo, hope that the industry colleagues can widely apply the high-tech hydraulic control system to forklift trucks and other industrial vehicle manufacturing field. In order to promote the quality improvement of forklift performance in our country.
Choose DIG-DOG for high-quality, customizable brush cutters for skid steers with fast delivery. Contact us today to discover how our superior products can enhance your land management tasks!
for more info just visit our website at www.dig-dog.com
contact # : +86 158 6218 2088
email : sales@bonovogroup.com
First, the working principle of forklift
Taking counterweight forklifts as an example, forkliftare generally divided into the following seven systems, namely power system (engine, motor), walking system (gearbox, torque converter, axle, driving wheel, etc.), braking system, electrical system, steering system, working device, and hydraulic system. The hydraulic system is an important part of the forklift, the working device and the steering system are driven by the hydraulic system. Therefore, the hydraulic system of forkliftdirectly affects the performance of forklift. A simple forklift hydraulic system is generally composed of power source (engine, motor) gear oil pump, high pressure oil pipe, multi-way valve, lifting cylinder, tilt cylinder, steering cylinder and some other control valves. The working principle is that the engine (motor) drives the hydraulic gear pump to continuously produce high pressure oil (gear pump principle is the same as the engine oil pump). The hydraulic oil is sucked out from the oil tank and enters the multi-way valve through the oil pipe. According to different working conditions, the operation handle can be pulled to realize the lifting, landing, forward leaning, backward leaning, and steering wheel steering. So as to achieve the forklift handling, loading and unloading of goods to meet people's requirements.
Two, forklift hydraulic system control examples
1. Hydraulic control system of all-electric stacker truck
Full hydraulic electric forklift hydraulic system is a new type of hydraulic control system independently developed by a company in China with patent rights. The working and control schematic diagram is as follows:
The hydraulic system mainly consists of the following areas: a working device composed of a lifting cylinder and a tilting cylinder; The steering system is composed of a steering device and a steering cylinder; The walking system is composed of a hydraulic motor and a hydraulic motor brake and a hydraulic motor speed regulating valve arranged on the hydraulic motor.
The working characteristics of the hydraulic system are that the three parts of the working device, the steering system and the walking system are driven by a motor to run a gear pump to obtain the required hydraulic energy to work. The hydraulic energy generated by the gear pump is output in two ways: one way is supplied to the steering device through the priority valve and the working device controlled by the multi-way valve to realize the lifting and lowering operation of the cargo fork; The other path leads through the pressure switching valve to the drive device controlled by the control valve and the reversing brake valve. This system replaces variable pump with gear pump, which is convenient to control the motor gear pump through the electrical system, and overcomes the defects of low efficiency, high energy consumption, high oil temperature and poor stability performance of hydraulic motor, walking and braking caused by long-term use.
2. Regenerative forklift hydraulic control system
Compared with the traditional forklift truck, the walking mechanism is two wheel type hydraulic motors, which can be conveniently installed in the corresponding position of the forklift chassis, saving the chassis space of the forklift truck. It is easy to arrange the door frame and reduce the weight of the forklift. By changing the direction of the oil through the reversing valve, the forklift can be made to move forward or backward, saving the driveway size of the warehouse and increasing the utilization rate of the stacking site. Compared with the traditional mechanical transmission, the full hydraulic transmission omits a set of complex reducer, differential, half shaft and other components, and the hydraulic system can be made into an integrated valve block, which makes the structure simple. The application range of the hydraulic system is large, 0.5-2.5 tons of all kinds of forklifts, even stacking tractors, trucks, etc., can be used, and can quickly introduce new varieties, which can greatly simplify the production process equipment of manufacturers. The hydraulic forkliftuses only one motor to drive the entire working device and walking mechanism, and the wave pump and motor are completely immersed in the oil to reduce noise, which is more concise and quiet than the traditional forklift truck.
3. Working process of hydraulic system
When the vehicle starts, the electric signal is sent out through the pedal, so that the motor drives the hydraulic pump to work. Because the motor adopts frequency conversion speed regulation, the non-working state is equivalent to the idle state. At this time, the motor power is only 10% of the rated working state. Hydraulic pump hydraulic oil into the reversing valve, through the reversing valve, the hydraulic oil into the hydraulic motor, drive the wheel rotation. When the reversing valve is in the middle position, the hydraulic oil flows back to the tank. With the reversing valve in the left or right position, complete the forkliftforward or backward. When the forklift truck slows down and stops without emergency braking, due to the inertia of the forklift truck, the wheel drives the hydraulic motor to rotate, so that the hydraulic motor becomes a hydraulic pump condition. A check valve is arranged on the suction line to prevent the pressure oil output by the hydraulic motor from flowing back to the tank and entering the hydraulic pump. The hydraulic pump rotates with the motor, at this time the hydraulic pump becomes a hydraulic motor, the motor becomes a generator, and the electricity emitted is quickly charged to the electric storage oil. When the forklift lifts the goods, the variable hydraulic pump is also driven by the motor. The variable hydraulic pump outputs the oil into the reversing valve. When the reversing valve is on the right, the oil directly enters the hydraulic cylinder to lift the heavy objects.
Third, compared with foreign forklift hydraulic system problems in our country To battery balance forklift truck as an example, the current domestic battery forklifttruck is in a relatively backward state, there are four main problems:
1, there is no energy recovery function, resulting in short working time of the forklift, more power consumption of the forklift, serious loss of the brake device and other problems.
2, the energy consumption is large, the current domestic forklift truck generally uses a quantitative hydraulic pump, adopt the throttling way to speed regulation.
3, the noise is relatively large, due to the defects of the motor and the wave pump used in the manufacturing process of the domestic forklift truck, the noise of the forklifttruck is much larger than that of foreign forklifts.
4, the structure size is large, most domestic battery forklift lifting, tilt and steering using hydraulic transmission, walking using mechanical transmission, resulting in a low power to volume ratio, the same tonnage of forkliftvolume is too large.
5, the failure rate is high, the quality stability of domestic hydraulic components is poor, the leakage phenomenon is serious.
In foreign countries, forklift hydraulic systems generally use stepless speed regulation and energy recovery, but most of them are limited to kinetic energy recovery; The power device of the hydraulic system, more use of variable frequency motor to drive the quantitative, variable hydraulic pump drive device, this device can achieve the purpose of energy saving: install a number of flow sensors and pressure gauges in the oil circuit, monitor the system, and through the installation of sensors for feedback, to achieve a high control accuracy.
Four, the development direction of hydraulic control on the forklift
1, energy saving and electromechanical hydraulic integration of high technology application
The development and application of microelectronics technology, sensing technology and information processing technology will improve the overall level of the forklift industry, achieve composite functions, and ensure the safety, control and automation level of the whole machine and system, so that the combination of electronics and machinery, electronics and hydraulics will be closer. The future development of forklifts lies in the application level of its electronic technology. For example, the Linde electric forward lift truck uses an inductive electronic steering system to provide variable torque feedback to the operator to ensure perfect control performance, requiring very little steering force. The realization of the microprocessor as the core of the electromechanical hydraulic integration is the main direction of the future development of forklift control system, that is, with the microprocessor as the core, the control from local control to the network direction, so that the vehicle to maintain a good working condition, to achieve the intelligent operation of forklift. Using electronic steering system and power steering ratio can save 25%, it can control the motor speed timely according to the working condition of forklift truck, which is an effective measure for energy saving and noise reduction of forklifttruck. In addition, MOSFET transistor than resistance speed regulation can save 20%, release regenerative braking can save 5-8%, the use of hydraulic motor controller and load potential energy recovery technology can save 20% and 5% respectively.
2, micro control pedal instead of the general forklift foot pedal
When operating a forklift truck, the driver often fails to grasp the strength of the foot carelessly, causing avoidable losses. The micro control pedal enables the driver to move precisely on the micro surface, which can better control the operation of the forklift and avoid various operational errors. The micro-motion control pedal can ensure the precise operation of the forklifttruck in the short-distance accurate positioning, especially in the large volume and quantity of the loaded goods, the good effect of the micro-motion control pedal is more obvious.
In short, at present, the use of advanced hydraulic control technology of forklifttrucks in China is less, the quality stability of hydraulic basic parts is poor, resulting in China's forklift trucks in the field of hydraulic control lags behind foreign countries, the technical added value of products is low, low international competitiveness and other status quo, hope that the industry colleagues can widely apply the high-tech hydraulic control system to forklift trucks and other industrial vehicle manufacturing field. In order to promote the quality improvement of forklift performance in our country.
Choose DIG-DOG for high-quality, customizable brush cutters for skid steers with fast delivery. Contact us today to discover how our superior products can enhance your land management tasks!
for more info just visit our website at www.dig-dog.com
contact # : +86 158 6218 2088
email : sales@bonovogroup.com