WO2009100578A1

WO2009100578A1 - A full hydraulic ac electrical forklift

Info

Publication number: WO2009100578A1
Application number: PCT/CN2008/000316
Authority: WO
Inventors: Yong Chen
Original assignee: Zhejiang Jiali Technology Co., Ltd.
Priority date: 2008-02-04
Filing date: 2008-02-04
Publication date: 2009-08-20
Also published as: CN101711221A; GB2471217B; CN101711221B; DE112008003677T5; GB201014327D0; GB2471217A

Abstract

A full hydraulic AC electrical forklift, includes a hydraulic system and a electrical system. An accelerator of the electrical system controls the steering equipment and walking-driver equipment of the hydraulic system. The elevating and oblique switch, by way of an AC controller, controls the AC motor to drive the gear pump of the hydraulic system, and further controls the oblique elevating equipment by a multi-path valve. A stepless speed regulator system is composed of AC controller, AC motor and accelerator, which makes the walking system shift from low-speed to high-speed more freely, steadily, and reliably. Moreover, the AC controller is designed in this manner by which not only realizes the stepless speed regulation of the hydraulic walking system but also realizes the elevated and oblique control of the hydraulic system. This invention centers on the single AC motor and combines the design of the electrical system and that of the hydraulic system, in order to resolve the present technical problems of the large current, vast dissipation, high temperature, and the complicated circuit.

Description

Full hydraulic AC electric forklift technology

The invention relates to an electric forklift, in particular to a fully hydraulic AC electric forklift.

Background technique

The electrical principle design of the existing hydraulic electric forklift (such as the Chinese patent of ZL01125120. 4, the publication number is CN1405079A) is based on the DC controller to control the DC motor, and the technical solution of the forklift is in this application. No. 200610050420. No. 6 Chinese invention patent application "Full hydraulic electric forklift hydraulic system" (publication number: CN101058395A) and 200610050421. No. 0 Chinese invention patent application "Full hydraulic electric forklift electrical system" (publication number: CN101058396A) As mentioned above, this type of drive not only has low transmission efficiency and high noise, but also tends to maintain and replace the carbon brush in the motor, and causes large running current, high energy consumption, high temperature, and relatively short running time of the forklift. And the control of the motor is realized by the DC controller. This kind of electrical control method can not effectively control the motor, nor can it perform thermal drop control and heat rise protection on the temperature rise of the motor. For example: No frequency conversion vector speed control , no safety sensing control, etc.).

The invention solves the technical problems and the technical tasks to be solved by the prior art that the forklift has the disadvantages of large current, high energy consumption, high temperature and complicated connecting lines, and provides a new full-hydraulic AC electric forklift. To this end, the present invention adopts the following technical solutions:

Fully hydraulic AC electric forklift, including hydraulic system and electrical system, featuring:

The hydraulic system includes:

A tilting device consisting mainly of a lifting cylinder and a tilting cylinder and controlled by a multi-way valve, mainly composed of a steering device composed of a steering gear and a steering cylinder.

a travel drive consisting of a hydraulic motor and a hydraulic motor brake and a hydraulic motor speed control valve disposed on the hydraulic motor and controlled by a control valve and a reversing brake valve, and

a gear pump, the hydraulic energy generated by the gear pump is divided into two outputs: one via a priority ceramic supply to the steering device and the tilting lifting device, and the other through a pressure switching valve to the driving device; The electrical system includes:

Battery power, key switch, an AC motor and AC sensing control system, '

The battery power source is used as the energy source to be connected by the emergency stop switch and divided into the high voltage power source and the low voltage power source by the DC-DC transformer. The low voltage power source is connected to the AC sensor control system via the key switch, and one is mainly used for the control station. An AC controller of the AC motor, and an instrument connected to the AC controller, a temperature sensor,

a high voltage power supply is connected to the AC controller through a fuse and is connected to the AC motor via a main contactor controlled by the AC controller, and an accelerator and a lifting and tilting switch are connected to the AC controller. And turn on the load relay, insulation monitor, heat drop control, electronic protection grid, safety function switch;

The steering device and the traveling drive device are controlled by the accelerator, and the hoisting and tilting switch controls the AC motor to drive the gear pump via the AC controller and further controls the tilting and lowering device via the multi-way valve.

During operation, the battery power supply passes through the DC-DC transformer to the key switch. When the key switch is disconnected from the circuit, the electrical system and the hydraulic system stop working. When the key switch is turned on, the high voltage power supply is connected to the AC controller, and the main contactor is closed: at this time, if the accelerator is turned on, the AC motor is turned on by the AC controller output, and the AC motor is set by the AC controller. The idle speed of the forklift truck, with the acceleration of the accelerator (such as pedaling accelerator with foot), the speed of the AC motor runs from low speed to high speed, driving the gear pump to work for the steering device and the travel drive; In the original state (accelerator disconnect circuit), the forklift is still idle during the time set by the AC controller, until the set time is over, the system power is turned off; at this time, if the lift and tilt switches are turned on, the AC control is performed. The control of the AC motor runs the gear pump to operate the tilting lift.

The advantages of the invention are:

1. The stepless speed regulation system formed by the AC controller, AC motor and accelerator makes the traveling system free, stable and reliable from slow to fast running, and the AC controller is designed to realize the hydraulic walking stepless adjustment. The speed can realize the hydraulic lifting and tilt control (the accelerator is connected to the AC controller to control the motor to drive the gear pump to realize the hydraulic walking stepless speed regulation, and then the lifting and tilting switch is connected to the AC controller to control the motor to drive the gear pump to realize the operation. Lifting and tilting control of the forklift).

2. After the system is started, it is only in the idle state (set a minimum speed on the AC controller program, and the AC controller controls the motor to work at low speed), so that the steering system of the hydraulic system ensures energy supply within a certain period of time. The delay is turned off when not working, so that the system energy is not wasted and the energy consumption of the whole machine is reduced. 3, because it is a single-motor stepless speed regulation work, plus the motor must have the characteristics of the pump motor and the characteristics of the travel motor, so the form of the motor is AC, and its working time system is designed for 60 minutes, so the motor meets Conditions for hydraulic walking and hydraulic lifting.

4. The system has automatic fault diagnosis function, which displays the fault code through the instrument, which facilitates technical service.

5. The starting performance is good. Because the AC motor is maintenance-free, high efficiency, low current, low noise, etc., it will not cause damage to the motor and consume less energy.

In short, this combination of electrical system and hydraulic system design with a single AC motor as the core improves the efficiency of the whole system, reduces energy consumption, reduces maintenance, increases the safety of the whole machine, and is simple in structure. Flexible operation and enhanced functions.

Attachment

Figure 1 is a schematic view of a hydraulic system of the present invention.

Fig. 2 is an electrical schematic diagram of the present invention, wherein (a), (b), and (c) are electrical schematic diagrams of three portions of the electrical schematic diagram of the present invention which may be sequentially connected.

In the figure: 1 steering device, 2 - control 闽, 3 - multi-channel 4, 4 - tilting lifting device, 5 - walking drive device, 6 - reversing brake 闽, 7 - pressure switching valve, 8 - gear pump, 9-AC motor, 10 one fuel tank, 11 lift cylinder, 12-tilt cylinder, 13-steering, 14-steering cylinder, 15-tilt valve, 16-lift valve, 17-running unloading, 18-tone Pressure shift valve, 19-way reversing valve, 20 one brake valve, 21-two-speed hydraulic motor, 22-hydraulic speed control valve, 23-hydraulic brake, 24-second pressure regulating valve, 25-back pressure valve, 26—pressure reducing valve, 27—relief valve, 28—relief valve, 29—relief valve, 30—priority 闽;

201—battery power supply, 202—emergency stop switch, 203—key switch, 204—main contactor, 205 one temperature sensor, 206—insulation monitor, 207—overload relay, 209—AC controller, 210 one meter, 211— Fuse, 212 - lift tilt switch, 213 - DC-DC transformer, 214 - accelerator switch, 215 - thermal drop control sensor, 216 - electronic protection grid, 217 - system safety function switch.

detailed description

The full hydraulic AC electric forklift of the present invention comprises a hydraulic system and an electrical system, wherein: the hydraulic system is as shown in FIG. 1 and includes:

A single AC motor 9 and a gear pump 8 connected by a transmission constitute a power unit;

The tilting lifting device 4 is composed of a lifting cylinder 11 and a tilting cylinder 12;

The steering device 1 is composed of a steering gear 13 connected with a priority valve 30 and a steering cylinder 14; The traveling drive device 5 is composed of a two-speed hydraulic motor 21, a hydraulic brake 23 disposed on the motor, and a hydraulic speed regulating valve 22;

The hydraulic brake 23 is controlled by the travel unloading brake valve 17 of the control valve 2;

The multi-way valve 3 is composed of a tilt valve 15, a lift-up width 16, and the like: a multi-way valve 3 is provided with an overflow valve 27 for controlling the system pressure of the tilting lifting device 4, the main oil passage and the tilting valve 15 The lift valve 16 is provided with an overflow width 28 to control the lifting pressure, the tilt valve 15 is connected to the tilt cylinder 12, and the lift valve 16 is connected to the lift cylinder 11;

The control valve 2 is composed of a travel unloading valve 17, a pressure regulating shift valve 18, and the like: a control valve 2 is provided with a pressure reducing valve 26 on the main oil passage of the oil inlet valve to control the pressure, and the pressure regulating valve 18 - oil port and secondary adjustment The pressure is widened to 24, and the other port is connected to the hydraulic motor 闽22; the travel unloading valve 17-the oil port is returned to the oil tank 10 via the back pressure valve 25, and the other oil port is connected to the hydraulic motor brake 23;

The commutation brake width 6 is changed by the travel reversing 闽19, the brake valve 20, etc. ^ 3⁄4: The reversing brake valve 6 is provided with a relief valve 29 to control the pressure at the inlet; the reversing valve 19 is the return tank The other two ports are respectively connected to the positive and reverse ports of the hydraulic motor 21; the brake valve 20 is connected between the traveling reversing valve 19 and the hydraulic motor 21;

The pressure switching valve 7 is composed of a secondary pressure regulating port 24 and a back pressure valve 25, etc.: the secondary pressure regulating width 24 is connected with the control valve 2 and the gear outlet of the gear pump 8, and the back pressure valve 25 is connected to the oil returning path and the fuel tank 10 Between

The circuit composed of the control valve 2, the gear pump 8, the two-speed hydraulic motor 21, the reversing brake valve 6, and the pressure switching valve Ί serves as a hydraulic speed control circuit.

The electrical system is shown in Figure 2, which includes battery power supply 201, emergency stop switch 202, key switch 203, an AC motor 9 and an AC sensing control system:

The battery power source 201 is used as an energy source to divide the power source into a high-voltage power source and a low-voltage power source through the DC-DC transformer 213. The low-voltage power source is connected to the AC sensor control system via the key switch 203, and the main switch is controlled by the accelerator switch 214. The AC controller 209 of the AC motor 9; the voltage source is connected to the AC controller 209 and is connected to the AC motor 9 via the main contactor 204 controlled by the AC controller 209, and the accelerator 214 is connected to the AC controller 209. Lifting the tilt switch 212;

And: the AC motor 9 is operated for 60 minutes, and the AC controller 209 is connected to the meter 210. The low-voltage power source controls the power through the AC controller 209 via the function switches, and displays the accurate power through the meter 210; and has an automatic diagnosis function. The AC controller 209 displays a fault through the meter 210 for a system failure.

The AC sensing control system includes: an AC controller 209, an overload relay 207, a temperature sensor 205, an insulation monitor 206, a heat drop control sensor 215, an electronic protection grid 216, and the like. When the electrical system is in operation, the battery power source 201 is passed through the emergency stop switch 202 to the key switch 203. When the key switch 203 is turned on, the DC-DC transformer 213 is divided into two power supply outputs:

When the AC controller 209 is connected to a high voltage such as a 70V power source, the main contactor 204 is sucked and displayed by the meter 210 to display the power and the working state; when the accelerator switch 214 is turned on, the AC motor 9 is output through the AC controller 209, which is The AC motor 9 is in an idle state set by the AC controller 209. With the displacement of the accelerator 214 (foot pedal type), the rotational speed of the AC motor 9 is operated from a low speed to a high speed, and the gear pump is driven to operate for the steering device and the traveling drive device. When the accelerator switch 214' is in the original state (disconnecting the circuit), the AC motor 9 still keeps the system in the idle working state within the time set by the AC controller 209, until the set time is completed, the system power is turned off; When the up-and-down switch 212 is turned on, the AC motor 9 is controlled by the AC controller 209 to operate the gear pump 8 to operate the tilt lift device 4.

The other way is a low voltage such as 24 volts. When the key switch 203 is turned on, it is connected to the AC controller 209 through the insulation monitor 206. Since the insulation monitor 206 is connected to the whole circuit, when the insulation value of the whole circuit appears, the insulation is monitored. When the set value of the device 206 is controlled by the AC controller 209, the whole machine does not work (for example, when the insulation resistance of the battery 201 is lower than the standard); when the power is turned on, the working power source is connected to the AC controller 209 through the overload relay 207, when the operating current is When it is too large, the overload relay 207 turns off the power signal of the AC controller 209 to stop the whole system; when the system temperature is too high, the sensing signal is sent to the AC controller 209 through the heat drop temperature sensor 215 and is lowered by the AC controller 209. The operating load of the whole system is used to achieve the purpose of controlling the temperature rise of the system; when the system temperature exceeds the set standard, the temperature sensor 5 sends a sensing signal to the AC controller 209 and stops the whole system through it, when the temperature is lowered to When the setting is lower than the set standard, the whole machine automatically recovers the function; the system safety function switch 217 and the accelerator Guan 214 is connected via an electronic protection barrier 216 and communication controller 209, the function switch occurs when an abnormal operational state, the electronic blocking protection barrier 216 will play a protective role, the controller 209 exchanges will not work.

The following is a detailed description of the work of the forklift of the present invention in conjunction with a hydraulic system and an electrical system:

With the battery 201 as an energy source, when the key switch 203 is turned on, the 70V and 24V power sources are turned on by the DC-DC transformer 213, at which time the main contactor 204 is pulled in and the electrical system is energized.

When the pedal accelerator switch 214 is opened (the start switch is set in the accelerator, and the accelerator pedal start switch is turned on), the AC controller 209 controls the AC single motor 9 to directly drive the gear pump 8 to idle (the idle speed is The AC controller program is set to speed, and the flow leads to the hydraulic system to meet the displacement demand of the steering gear 13 to achieve the function of turning the forklift in place.

The forward and backward movement of the forklift is changed by manipulating the travel reversing valve 19, and the rotation speed of the AC motor 9 is controlled by the AC controller 209 by the stroke of the pedal accelerator 214 to control the displacement of the gear pump 8 to the liquid. The pressure motor 21 controls the traveling speed of the forklift; when the accelerator 214 is released and the brake valve 20 is depressed, the throttles of the A, B oil passages of the hydraulic motor 21 are closed.

The speed reversing valve 18 in the control valve 2 is operated and passed through the secondary pressure regulating valve 24 in the pressure switching valve 7 to realize high pressure and low pressure and pass through the hydraulic speed regulating valve 22 in the hydraulic motor 21 to achieve the climbing and climbing function of the forklift. And the high-speed walking function; the function of the traveling operation and the system unloading is changed by the traveling unloading brake valve 17 in the control valve 2, and the hand brake is realized by the hydraulic brake 23 in the hydraulic motor 21 through the wide brake gear.

In the multi-way valve 3, the lifter 16 and the tilting valve 15 are respectively provided with a micro-stroke limit switch 212, and when the lift valve 16 is operated, the installed stroke switch is closed to turn on the AC controller 209 to control the AC motor 9 to drive The full operation of the gear pump 8 causes the forklift to reach the take-off and landing function; the same principle is applied to the tilting valve 15 to achieve the tilting function of the forklift.

When the AC controller 209 controls the AC single motor 9 to idle, the energy can satisfy the demand of the steering system, and can play the role of low load and low energy consumption. Under normal working conditions, due to the configuration of the steering gear 13 The priority valve 30 makes the forklift turn sensitive and ensures that the forklift always has the priority to steer during any movement.

When the accelerator switch 214 is in the original state (open circuit), the AC controller 209 still keeps the system in the idle state for a set time, and the system power is turned off once the set time is reached (the delay time is in the AC controller program). Setting), this ensures that the steering function is guaranteed for a certain period of time without operation.

When the system malfunctions or an operation error occurs, the fault is displayed in the English and digital form on the meter 210 through the automatic diagnosis function in the AC controller 209, which facilitates the technical service.

Adopting AC variable frequency vector speed control, its flexibility, high accuracy and sturdy transmission make the forklift have good transmission efficiency, low temperature and low running current. Since AC motors do not have carbon brushes and commutators, AC motors are maintenance-free.

When the whole machine is working, the electrical system can conveniently set and adjust the working state of the hydraulic running system through the AC controller 209, and the load on the electrical system can be adjusted through the adjustment of the pressure switching valve 7 and the traveling relief brake valve 17. Overcurrent protection.

Claims

Claim

1. A fully hydraulic AC electric forklift comprising a hydraulic system and an electrical system, characterized in that: the hydraulic system comprises:

Mainly composed of a lifting cylinder (11) and a tilting cylinder (12) and consisting of a multi-way valve (3 controlled tilting lifting device (4),

a steering device (1) consisting mainly of a steering gear (13) and a steering cylinder (14),

It consists of a hydraulic motor (21) and a hydraulic motor brake (23) and a hydraulic motor speed control valve (22) arranged on the hydraulic motor (21) and consists of a control valve (2) and a reversing brake valve (6). Controlled travel drive (5), and

a gear pump (8), the hydraulic energy generated by the gear pump (8) is output in two ways: one way is supplied to the steering device (1) and the tilting lifting device (4) via a priority valve (30), The other way leads to the travel drive (5) via a pressure switch 闽 (7);

The electrical system includes:

Battery power supply (201), key switch (203), an AC motor (9) and AC sensor control system,

The battery power supply (201) is used as an energy source to be turned on by the emergency stop switch (202) and divided into a high voltage power supply and a low voltage power supply by the DC-DC transformer (213). The low voltage power supply is connected to the AC via the key switch (203). a sensing control system, an AC controller (209) mainly for controlling the AC motor, and a meter (210) connected to the AC controller (209), a temperature sensor (205), and a high voltage power supply A fuse (211) turns on the AC controller (209) and turns on the AC motor (9) via a main contactor (204) controlled by the AC controller (209), in the AC control An accelerator (214) and a lifting and tilting switch (212) are connected to the device (209), and the load relay (207), the insulation monitor (206), the heat drop control (215), and the electronic protection grid (216) are connected. , safety function switch (217); '

The steering device (1) and the travel drive device (5) are controlled by the accelerator (214), and the lifting and tilting switch (212) is controlled by the AC controller (209) to control the AC motor (9). The gear pump (8) is further controlled by a multi-way valve (3) to tilt the lifting device (4).

2. The hydraulic system of a fully hydraulic electric AC forklift according to claim 1, wherein said multi-way valve (3) comprises three-way six-way control for separately controlling the lifting cylinder (11) and the tilting cylinder (12). The valve acts as a lift valve (16) and a tilt valve (15), and a tilting lift overflow (27) is provided on the main oil passage of the multi-way valve (3) to control the lift cylinder (11) One on the three-position six-way valve Lift pressure relief valve (28).

3. The hydraulic system of a fully hydraulic electric AC forklift according to claim 1 or 2, wherein the pressure switching valve (7) comprises a secondary pressure regulating width (24) and a back pressure wide (25); Control valve

(2) Including a travel unloading valve (17) and a pressure regulating shift valve (18), a decompression crucible (26) is provided on the main oil passage of the control valve (2), and one of the pressure regulating shifting valves (18) The oil port is connected to the secondary pressure regulating valve (24), and the other oil port is connected to the hydraulic motor speed regulating valve (22), and a port of the running unloading valve (17) is passed through the back pressure valve (25) Return to the tank and the other port is connected to the hydraulic motor brake (23).

4. The hydraulic system of a fully hydraulic electric AC forklift according to claim 3, wherein said reverse brake valve (6) comprises a travel reversing valve (19) and a brake valve (20); The reversing brake valve (19) is a three-position spool valve, and its inlet port is provided with a relief valve (29), wherein the position is connected to the fuel tank, and the other two ports are respectively positive and negative with the hydraulic motor (21). Connected to the port; the brake valve (20) is connected between the travel reversing valve (19) and the hydraulic motor (21). '