CN114506800A - Electric fork truck portal motion control system - Google Patents

Electric fork truck portal motion control system Download PDF

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Publication number
CN114506800A
CN114506800A CN202210413038.6A CN202210413038A CN114506800A CN 114506800 A CN114506800 A CN 114506800A CN 202210413038 A CN202210413038 A CN 202210413038A CN 114506800 A CN114506800 A CN 114506800A
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China
Prior art keywords
controller
way valve
oil
opening degree
opening
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CN202210413038.6A
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Chinese (zh)
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CN114506800B (en
Inventor
李婧
金盈超
肖军成
裴伟
游颖捷
罗升
何景泉
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Hangcha Group Co Ltd
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Hangcha Group Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/08—Masts; Guides; Chains
    • B66F9/082—Masts; Guides; Chains inclinable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F15B13/08—Assemblies of units, each for the control of a single servomotor only
    • F15B13/0803—Modular units
    • F15B13/0846—Electrical details
    • F15B13/085—Electrical controllers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F15B13/08—Assemblies of units, each for the control of a single servomotor only
    • F15B13/0803—Modular units
    • F15B13/0846—Electrical details
    • F15B13/086—Sensing means, e.g. pressure sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/275—Control of the prime mover, e.g. hydraulic control

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Civil Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Analytical Chemistry (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The invention discloses an electric forklift gantry action control system, which is used in the technical field of forklift gantry control.A port A of a multi-way valve is used for being communicated with a rodless cavity of a lifting oil cylinder; when the controller receives a lifting signal and the opening O of the controller is less than or equal to O12, the controller controls the total flow of the hydraulic oil of the oil pump to be greater than the accessible flow of the multi-way valve; when the controller receives a lifting signal and the opening O12 of the controller is larger than O and is less than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve. And the throttle speed regulation is adopted at low rotating speed, and the volume speed regulation is adopted at high rotating speed, so that the micro-motion performance of the door frame action is improved, and the overall energy consumption is reduced.

Description

Electric fork truck portal motion control system
Technical Field
The invention relates to the technical field of forklift mast control, in particular to an electric forklift mast action control system.
Background
In the prior art, the controller controls the flow of the hydraulic oil provided by the oil pump to be always larger than the flow which can be passed by the multi-way valve, so that the waste of the hydraulic oil is caused, and the energy consumption of the whole vehicle is improved; meanwhile, the hydraulic oil flow is used for limiting the action speed of the door frame, the volume speed regulation of the oil pump is suitable for the rapid action of the door frame, but the fine adjustment of the action of the door frame is difficult to realize, and the micro-motion performance is poor.
In summary, how to improve the inching capability of the forklift mast motion control system and reduce energy consumption is a problem to be solved urgently by those skilled in the art.
Disclosure of Invention
In view of this, the present invention provides an electric forklift mast action control system, which not only improves the micro-motion performance of the mast action, but also reduces the overall energy consumption.
In order to achieve the above purpose, the invention provides the following technical scheme:
the controller is used for controlling the opening degree of the multi-way valve and the rotating speed of the motor, at least one opening A of the multi-way valve is used for being communicated with a rodless cavity of a lifting oil cylinder, when the controller receives a lifting signal, the opening A is opened by the controller and the motor is controlled to drive the oil pump to rotate, so that hydraulic oil in the hydraulic oil tank can enter the rodless cavity of the lifting oil cylinder through the oil pump and the opening A of the multi-way valve, and the opening degree of the opening A and the rotating speed of the motor are gradually increased along with the increase of the opening degree O of the controller;
when the controller receives the lifting signal and the opening degree O of the controller is not more than O12, the controller controls the total flow of hydraulic oil of the oil pump to be larger than the accessible flow of the multi-way valve;
when the controller receives the lifting signal and the opening O12 of the controller is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the accessible flow of the multi-way valve;
wherein the O12 is a first preset lifting opening degree.
Preferably, the number of the oil pumps is two, and the motors correspond to the oil pumps one by one;
when the controller receives the lifting signal and the opening O of the controller is not more than O11, the controller controls a single motor to drive the oil pump to rotate, and the flow rate of hydraulic oil of the single oil pump is larger than the accessible flow rate of the multi-way valve;
when the controller receives the lifting signal and the opening degree O11 of the controller is larger than O and is not larger than O12, the controller controls the two motors to drive the oil pumps to rotate, and the total flow of hydraulic oil of the two oil pumps is larger than the passing flow of the multi-way valve;
when the controller receives the lifting signal and the opening O12 of the controller is larger than O and is less than or equal to 100%, the controller controls the two motors to drive the oil pumps to rotate, and the total flow of hydraulic oil of the two oil pumps is smaller than the accessible flow of the multi-way valve;
and the O11 is a second preset lifting opening, and O11 is less than O12.
Preferably, a speed-limiting valve is arranged between the rodless cavity of the lifting oil cylinder and the multi-way valve, and when the controller receives a descending signal, the controller closes the motor and opens the port A corresponding to the lifting oil cylinder, so that the hydraulic oil flows back into the hydraulic oil tank through the speed-limiting valve and the multi-way valve;
the opening degree of the port A corresponding to the lifting oil cylinder is gradually increased along with the increase of the opening degree of the controller, and when the opening degree O of the controller is not more than O21, the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder is smaller than the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder when the opening degree O21 of the controller is not less than O22;
wherein the O21 is a first preset descending opening degree, and the O22 is a second preset descending opening degree.
Preferably, the port A3 of the multi-way valve is used for communicating with a rodless cavity of a tilt cylinder, and the port B3 of the multi-way valve is used for communicating with a rod cavity of the tilt cylinder;
when the controller receives an inclination signal, the controller opens the A3 port and controls the two motors to drive the oil pump to rotate, and the opening degree of the A3 port and the rotating speed of the motors are gradually increased along with the increase of the opening degree of the controller, so that the hydraulic oil can conveniently enter a rodless cavity of the inclination oil cylinder through the oil pump and the A3 port of the multi-way valve;
when the controller receives an inclination signal and the opening degree O of the controller is less than or equal to O31, the controller controls the total flow of the hydraulic oil of the oil pump to be greater than the passing flow of the multi-way valve;
when the controller receives the lifting signal and the opening O31 of the controller is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve;
wherein the O31 is a first preset inclination opening.
Preferably, the port a4 of the multi-way valve is used for communicating with the port a of the accessory valve and the rodless cavity of the second accessory cylinder, the ports B4 and a5 of the multi-way valve are both used for communicating with the port B of the accessory valve and the rodless cavity of the first accessory cylinder, and the port B5 of the multi-way valve is used for communicating with the rod cavity of the first accessory cylinder and the rod cavity of the second accessory cylinder;
when the controller receives an accessory action signal, the controller opens a working port of the multi-way valve corresponding to the accessory action signal and controls the two motors to drive the oil pump to rotate, and the opening degree of the working port and the rotating speed of the motors are gradually increased along with the increase of the opening degree O of the controller;
when the controller receives the accessory action signal and O is less than or equal to O41, the controller controls the total flow of the hydraulic oil of the oil pump to be greater than the passing flow of the multi-way valve;
when the controller receives the accessory action signal and O41 is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve;
wherein the O41 is a first preset accessory operation opening.
Preferably, a pressure sensor for detecting the pressure of a pump opening of the oil pump is arranged between the multi-way valve and the oil pump, the pressure sensor is connected with the controller, and when the pressure of the pump opening detected by the pressure sensor is greater than a preset overflow pressure, the controller closes the multi-way valve and reduces the rotating speed of the motor until the rotating speed is 0.
Preferably, the port T1 of the multi-way valve is communicated with the hydraulic oil tank through an oil return filter.
Preferably, the Pp port of the multi-way valve is connected with an accumulator.
When the electric forklift gantry motion control system works, a user inputs a lifting signal to the controller, the controller controls the opening of the port A communicated with the rodless cavity of the lifting oil cylinder and controls the motor to drive the oil pump to rotate, the oil pump pumps hydraulic oil in the hydraulic oil tank into the multi-way valve, and the hydraulic oil enters the rodless cavity of the lifting oil cylinder through the port A of the multi-way valve to lift the forklift gantry.
When the opening O of the controller is smaller than or equal to the first preset lifting opening O12, the controller controls the total flow of hydraulic oil of the oil pump to be larger than the accessible flow of the multi-way valve, the multi-way valve is utilized to limit the flow of the hydraulic oil entering the lifting oil cylinder, the flow of the hydraulic oil entering the lifting oil cylinder is stable and is not influenced by the fluctuation of the oil pump at low rotating speed, the defect that the volume speed regulation effect of the oil pump at low rotating speed is poor can be avoided, and the accuracy and the maneuverability of the micro-motion operation of the gantry motion are improved.
When the opening O of the controller is larger than O12 and smaller than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the accessible flow of the multi-way valve, so that the energy loss caused by throttling of the valve port of the multi-way valve is avoided, the overall energy consumption is reduced, the advantage of volume speed regulation of the oil pump at a high rotating speed is fully utilized, and the rapid action of the portal is realized.
Therefore, the electric forklift mast action control system provided by the invention effectively improves the micro-motion performance of the mast action and reduces the overall energy consumption.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a hydraulic schematic diagram of an embodiment of the electric forklift mast motion control provided by the present invention;
FIG. 2 is a schematic diagram showing the relationship between the opening of the multi-way valve, the rotation speed of the motor and the opening of the controller during lifting;
FIG. 3 is a schematic diagram showing the relationship between the opening of the multi-way valve, the rotation speed of the motor and the opening of the controller during descending operation;
FIG. 4 is a schematic diagram showing the relationship between the opening of the multi-way valve, the rotation speed of the motor and the opening of the controller during the tilting operation;
FIG. 5 is a schematic diagram showing the relationship between the opening of the multi-way valve, the rotation speed of the motor and the opening of the controller when the accessory is in operation;
FIG. 6 is a schematic diagram illustrating a relationship between a rotation speed of a motor and an opening of a controller during a lifting operation according to an embodiment;
FIG. 7 is a diagram illustrating a relationship between a digital value of a multi-way valve and an opening degree of a controller during a lifting operation according to an embodiment;
FIG. 8 is a diagram illustrating the relationship between the digital quantity of the multi-way valve and the opening of the controller during the descending operation according to an embodiment;
FIG. 9 is a schematic diagram illustrating the relationship between the rotation speed of the motor and the opening of the controller during the tilting operation according to an embodiment;
FIG. 10 is a diagram illustrating the relationship between the digital quantity of the multi-way valve and the opening of the controller during the tilting operation according to an embodiment;
FIG. 11 is a diagram illustrating a relationship between a rotation speed of a motor and an opening of a controller during an operation of an accessory according to an embodiment;
FIG. 12 is a diagram illustrating a relationship between a digital value of the multi-way valve and an opening of the controller during an accessory operation according to an embodiment.
In fig. 1-12:
the hydraulic oil tank 1, the oil pump 2, the motor 3, the multi-way valve 4, the lifting oil cylinder 5, the tilting oil cylinder 6, the accessory valve 7, the accessory oil cylinder 8, the speed limiting valve 9, the pressure sensor 10, the energy accumulator 11 and the oil return filter 12 are all arranged in sequence.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The core of the invention is to provide an electric forklift gantry action control system, which not only improves the micro-motion performance of gantry action, but also reduces the overall energy consumption.
Please refer to fig. 1-12.
It should be noted that, the controller mentioned in this document generally refers to a control handle of an electric forklift, and the controller opening O = (Δ L/L) × 100% with a movable pushing distance of the control handle being L and an actual pushing distance of the control handle being Δ L; the valve area of the multi-way valve 4 can be equally divided into M parts, that is, the digital quantity of the multi-way valve 4 is M, the digital quantity of the actual valve area of the multi-way valve 4 is M, and the opening of the multi-way valve 4 is M/M × 100%.
The invention provides an electric forklift gantry action control system which comprises a hydraulic oil tank 1, a controller, a multi-way valve 4, an oil pump 2 and a motor 3, wherein the controller is used for controlling the opening degree of the multi-way valve and the rotating speed of the motor, at least one opening A of the multi-way valve 4 is used for being communicated with a rodless cavity of a lifting oil cylinder 5, when the controller receives a lifting signal, the opening A is opened by the controller and the motor 3 is controlled to drive the oil pump 2 to rotate, so that hydraulic oil in the hydraulic oil tank 1 enters the rodless cavity of the lifting oil cylinder 5 through the opening A of the oil pump 2 and the opening A of the multi-way valve 4, and the opening degree of the opening A and the rotating speed of the motor 3 are gradually increased along with the increase of the opening degree O of the controller;
when the controller receives a lifting signal and the opening O of the controller is less than or equal to O12, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be greater than the accessible flow of the multi-way valve 4;
when the controller receives a lifting signal and the opening O12 of the controller is more than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the passing flow of the multi-way valve 4;
wherein O12 is a first preset lifting opening, the volume speed regulation of the oil pump 2 is considered to be beneficial to the quick lifting of the lifting oil cylinder 5, O12 is usually set to be less than or equal to 50%, and the specific value of O12 is determined according to factors such as the type of the electric forklift in actual production.
It should be noted that the opening degree of the port a and the rotation speed of the motor 3 both gradually increase with the increase of the opening degree O of the controller, and when the controller opening degree satisfies 0 < O1 < O2 < 100%, the opening degree O1 corresponding to the controller opening degree O1 is not more than the opening degree O2 corresponding to the controller opening degree O2, and the motor rotation speed n1 corresponding to the controller opening degree O1 is not more than the motor rotation speed n2 corresponding to the controller opening degree O2, and it is not mandatory that all O1 and O2 satisfy O1 < O2, n1 < n 2.
Referring to fig. 1, a1 and B1, a2 and B2, A3 and B3, a4 and B4, and a5 and B5 in fig. 1 are working ports of each unit of the multi-way valve 4, and the working ports are used for connecting with the lifting cylinder 5, the tilting cylinder 6, the accessory cylinder 8, and the like; a1 and b1, a2 and b2, a3 and b3, a4 and b4, and a5 and b5 are pilot valve working ports of all the multiple-way valve 4, and the pilot valves are in signal connection with a controller so that the controller controls the valve port opening of the corresponding working valve through the pilot valves; p, P2 and Pp are pressure oil inlets of the multi-way valve 4, and the Pp port of the multi-way valve 4 is connected with the accumulator 11; the T0 and the T1 are oil return ports of the multi-way valve 4, and a T1 port of the multi-way valve 4 is communicated with the hydraulic oil tank 1 through an oil return filter 12 so as to filter the returned hydraulic oil.
In order to realize the control of the lifting action of the forklift gantry, a port P of the multi-way valve 4 is communicated with a hydraulic oil tank 1 through an oil pump 2, and a port A of the multi-way valve 4 is communicated with a rodless cavity of a lifting oil cylinder 5. When the controller receives a lifting signal, pilot oil of the pilot valve is controlled to act on the port a of the multi-way valve 4, so that the corresponding port A on the multi-way valve 4 is opened, hydraulic oil flows into a rodless cavity of the lifting oil cylinder 5, and lifting of the forklift gantry is completed.
In actual production, the multi-way valve 4 can be communicated with a rodless cavity of the lifting oil cylinder 5 only by the port A of the working port of one joint; alternatively, as shown in fig. 1, the working port a1 of the first link and the working port a2 of the second link are both communicated with the rodless chamber of the lift cylinder 5.
When the forklift gantry lifting device works, a user inputs a lifting signal to the controller, the controller controls the opening A communicated with the rodless cavity of the lifting oil cylinder 5 to be opened, the motor 3 is controlled to drive the oil pump 2 to rotate, the oil pump 2 pumps hydraulic oil in the hydraulic oil tank 1 into the multi-way valve 4, and the hydraulic oil enters the rodless cavity of the lifting oil cylinder 5 through the opening A of the multi-way valve 4, so that the forklift gantry is lifted.
When the opening O of the controller is less than or equal to the first preset lifting opening O12, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be larger than the accessible flow of the multi-way valve 4, the opening of the multi-way valve 4 is used for limiting the flow of the hydraulic oil entering the lifting oil cylinder 5, the flow of the hydraulic oil entering the lifting oil cylinder is stable and is not influenced by the fluctuation of the oil pump 2 at a low rotating speed, the defect that the volume speed regulation effect of the oil pump 2 is poor at the low rotating speed can be avoided, and the accuracy and the maneuverability of the micro-motion operation of the gantry motion are improved.
When the opening degree O of the controller meets the condition that O is more than O12 and less than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the accessible flow of the multi-way valve 4, thereby avoiding the energy loss caused by the throttling of the valve port of the multi-way valve 4, reducing the overall energy consumption, fully utilizing the advantage of the volume speed regulation of the oil pump 2 at high rotating speed and realizing the rapid action of the portal.
Therefore, the electric forklift mast action control system provided by the embodiment effectively improves the micro-motion performance of the mast action and reduces the overall energy consumption.
In order to reduce the overall energy consumption, the total amount of hydraulic oil in the oil pump 2 is usually limited to not exceed the flow rate of the multi-way valve 4 when the opening O of the controller is not greater than O12. For example, the total flow of hydraulic oil is
Figure 474630DEST_PATH_IMAGE001
The flow rate of the multi-way valve 4 is
Figure 441449DEST_PATH_IMAGE002
Limit both of them to satisfy
Figure 681937DEST_PATH_IMAGE003
≤1.05
Figure 101417DEST_PATH_IMAGE002
。
The higher the rotating speed of the motor 3 is, the larger the opening degree of the multi-way valve 4 is, the larger the flow of hydraulic oil entering a rodless cavity of the lifting oil cylinder 5 in unit time is, and the faster the lifting speed of the forklift gantry is.
In the prior art, for the purpose of quick lifting of a forklift gantry, or a single high-power motor and a large-displacement oil pump are adopted, so that the type selection layout of the oil pump 2 and the motor 3 is limited; or a double-motor mode of the main motor and the auxiliary motor is adopted, the working conditions and working time difference of the main motor and the auxiliary motor are large, so that the service lives of the two motors 3 and the corresponding oil pumps 2 are greatly different, and the life cycle reliability of the whole vehicle and important parts is reduced.
On the basis of the above embodiment, please refer to fig. 1 and fig. 2, the number of the oil pumps 2 can be set to be two, and the motors 3 correspond to the oil pumps 2 one by one;
when the controller receives a lifting signal and the opening O of the controller is less than or equal to O11, the controller controls the single motor 3 to drive the oil pump 2 to rotate, and the flow rate of hydraulic oil of the single oil pump 2 is greater than the accessible flow rate of the multi-way valve 4;
when the controller receives a lifting signal and the opening degree O11 of the controller is greater than O and less than or equal to O12, the controller controls the two motors 3 to drive the oil pumps 2 to rotate, and the total flow of hydraulic oil of the two oil pumps 2 is greater than the accessible flow of the multi-way valve 4;
when the controller receives a lifting signal and the opening O12 of the controller is larger than O and is less than or equal to 100 percent, the controller controls the two motors 3 to drive the oil pumps 2 to rotate, and the total flow of hydraulic oil of the two oil pumps 2 is smaller than the accessible flow of the multi-way valve 4;
wherein O11 is the second preset lifting opening, O11 is more than O12, and O11 and O12 are determined according to the vehicle type of the electric forklift in actual production and other factors. O11 is mainly used for dividing the working area of the single oil pump at extremely low rotating speed, the value is not too high, and the value is usually set between 10% and 30%.
Referring to fig. 1, two oil pumps 2 and two motors 3 for driving the two oil pumps 2 respectively are disposed between a hydraulic oil tank 1 and a multi-way valve 4, and the two oil pumps 2 are respectively communicated with a port P and a port P2 of the multi-way valve 4. In order to control the rotation speed of the motor 3 and the total flow rate of the hydraulic oil of the oil pump 2 conveniently, the types and models of the two oil pumps 2 are generally set to be the same, and the types and powers of the two motors 3 are also set to be the same.
When the opening O of the controller is less than or equal to O11, the opening of the multi-way valve 4 is extremely small, the oil supply requirement can be met only by the single oil pump 2, the motor 3 is at an extremely low rotating speed, the hydraulic oil flow of the single oil pump 2 is controlled to be larger than the accessible flow of the multi-way valve 4, the hydraulic oil inflow of the lifting oil cylinder 5 is adjusted by utilizing the valve port opening of the multi-way valve 4, and the micro-motion of the lifting action of the gantry is realized by the throttling and speed regulating of the multi-way valve 4.
When the opening O11 of the controller is larger than O and smaller than or equal to O12, the opening of the multi-way valve 4 and the rotating speed of the motor 3 are increased relative to the opening O of the controller and smaller than or equal to O11, in order to meet the increased oil supply requirement, the two oil pumps 2 are controlled to work simultaneously, and the motor 3 drives the oil pumps 2 to rotate at a lower rotating speed, so that the total flow of the hydraulic oil of the two oil pumps 2 is larger than the accessible flow of the multi-way valve 4. At the moment, the opening degree of the valve port of the multi-way valve 4 is still utilized to adjust the hydraulic oil quantity entering the lifting oil cylinder 5, and the relative micro-motion of the lifting action of the gantry can be realized through the throttling and speed adjusting of the multi-way valve 4.
When the opening O12 of the controller is larger than O and is less than or equal to 100 percent, in order to realize the quick lifting of the lifting oil cylinder 5, the control motor 3 drives the two oil pumps 2 to work simultaneously, and the total flow of the hydraulic oil of the two oil pumps 2 is smaller than the accessible flow of the multi-way valve 4. At the moment, the opening of the valve port of the multi-way valve 4 does not limit the inflow of hydraulic oil of the lifting oil cylinder 5 any more, the lifting speed of the gantry is adjusted by utilizing the total flow of the hydraulic oil provided by the oil pump 2, and the rapid action of the lifting action of the gantry is realized through volume speed regulation.
It should be noted that, in the above process, when the two oil pumps 2 work simultaneously, the flow rates of the hydraulic oil output by the two oil pumps 2 at the same time may be controlled to be the same, or the flow rates of the hydraulic oil output by the two oil pumps at the same time may be controlled to be different. In order to avoid a great difference in the service life of the two oil pumps 2, the two oil pumps 2 are usually controlled to output the same flow rate of hydraulic oil at the same time.
Referring to fig. 2, the broken line ABC in the figure is a curve of the opening of the multi-way valve 4 with the controller opening, and a1b1cd and a2 back are curves of the motor speed of the motor 3 driving the two oil pumps 2 with the controller opening. And the coordinate axis of the motor rotating speed curve is the ratio of the actual rotating speed of the motor to the maximum preset lifting rotating speed.
It should be noted that, since the oil pump 2 is directly driven by the motor 3, the motor speed curve can also be regarded as the oil pump speed curve of the oil pump 2 driven by the motor.
When the controller opening degree O is less than or equal to O11, the controller controls the opening degree of the multi-way valve to gradually increase along with the increase of the controller opening degree O, and controls the rotating speed of the first oil pump to gradually increase to a first preset lifting rotating speed n 11;
when the controller opening degree O11 is larger than O and smaller than or equal to O12, the controller controls the opening degree of the multi-way valve to be continuously increased along with the increase of the controller opening degree O, the rotating speed of the second oil pump is gradually increased to a second preset lifting rotating speed n12, and the rotating speed of the first oil pump maintains the first preset lifting rotating speed n11 in the process;
when the controller opening degree O12 is larger than O and smaller than or equal to O14, along with the increase of the controller opening degree O, the controller controls the opening degree of the multi-way valve to be gradually increased to the maximum opening degree, and controls the rotating speeds of the first oil pump and the second oil pump to be gradually increased to the maximum preset lifting rotating speed, wherein when the controller opening degree is increased to the third preset opening degree O13, the rotating speed of the second oil pump is increased to the first preset lifting rotating speed n11, and then the rotating speed of the second oil pump and the rotating speed of the first oil pump are synchronously increased;
when the controller opening degree O14 is larger than O and is less than or equal to 100%, the controller controls the multi-way valve 4 to maintain the maximum opening degree and controls the first oil pump and the second oil pump to maintain the maximum preset lifting rotating speed.
It should be noted that preset lifting opening degrees such as O11, O12, O13, O14 and the like in the drawing are determined according to factors such as a vehicle model of the electric forklift in actual production, and the opening degree of the multi-way valve and the motor speed corresponding to the preset lifting opening degree, for example, the opening degree of the multi-way valve corresponding to the point a, the first preset lifting speed n11 corresponding to the section a1b1, the second preset lifting speed n12 corresponding to the section a2b2, and the like, may be selected according to an actual working condition of the electric forklift.
In an embodiment, please refer to fig. 6 and 7, the preset lift opening degrees of the controller are O11=20%, O12=30%, O13=35%, and O14=95%, respectively; the maximum preset lifting rotating speed of the first oil pump and the second oil pump is 2250r/min, the first preset lifting rotating speed n11 is 600r/min, and the second preset lifting rotating speed n12 is 450 r/min; the maximum digital quantity of the multi-way valve 4 is 250, and the digital quantity of the multi-way valve corresponding to the point A is 42.
In this embodiment, adopt the oil feed of double pump confluence mode during the portal fast action for two sets of oil pumps 2 are close with the life of motor 3, have prolonged holistic life, have improved the reliability of spare part in the whole life cycle.
On the basis of the above embodiment, a speed-limiting valve 9 is arranged between the rodless cavity of the lifting oil cylinder 5 and the multi-way valve 4, when the controller receives a descending signal, the controller closes the motor 3 and opens the port A corresponding to the lifting oil cylinder 5, so that the hydraulic oil flows back to the hydraulic oil tank 1 through the speed-limiting valve 9 and the multi-way valve 4;
the opening degree of the port A corresponding to the lifting oil cylinder 5 is gradually increased along with the increase of the opening degree of the controller, and when the opening degree O of the controller is less than or equal to O21, the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder 5 is less than the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder 5 when the opening degree O of the controller is more than O21 and less than or equal to O22;
the O21 is a first preset descending opening degree, the O22 is a second preset descending opening degree, the O21 is mainly used for dividing a micro-motion area for descending the portal frame, and the O22 is mainly used for dividing a full-speed descending area for descending the portal frame.
Considering the requirement of rapid descending of the portal, O21 is generally set to be less than or equal to 50%, and the specific value of O21 is determined according to factors such as the type of the electric forklift in actual production and the like; the opening degree of the multi-way valve 4 corresponding to the O21 is determined according to actual working conditions and the like.
Note that the opening degree of the port a described above gradually increases with the increase in the opening degree O of the controller, and when the controller opening degree satisfies 0 < O1 < O2 ≦ 100%, the port a opening degree O1 corresponding to the controller opening degree O1 is not more than the port a opening degree O2 corresponding to the controller opening degree O2, and it is not mandatory that O1 < O2 be satisfied for all of O1 and O2.
Referring to fig. 1, the speed-limiting valve 9 is disposed between the multi-way valve 4 and the rodless cavity of the lifting cylinder 5, and is used to limit the flow rate of the hydraulic oil that flows back from the lifting cylinder 5 to the multi-way valve 4, and the specific type, model, position, and installation manner of the speed-limiting valve 9 are determined according to the actual production requirements, and are not described herein again.
When the controller receives a descending signal, pilot oil of the pilot valve is controlled to act on the port b of the multi-way valve 4, so that the corresponding port A on the multi-way valve 4 is opened, hydraulic oil in the rodless cavity of the lifting oil cylinder 5 flows into the multi-way valve 4, and flows back to the hydraulic oil tank 1 through the oil return port T0 of the multi-way valve 4.
When the forklift gantry lifting device works, a user inputs a descending signal to the controller, the controller controls the motor 3 to be closed and controls the opening A communicated with the rodless cavity of the lifting oil cylinder 5 to be opened, so that hydraulic oil flows back into the hydraulic oil tank 1 through the speed limiting valve 9 and the opening A of the multi-way valve 4, and the forklift gantry descends.
When the opening O of the controller is less than or equal to the first preset descending opening O21, as shown in the section 0A in fig. 3, the opening of the multi-way valve 4 is small, and at this time, the multi-way valve 4 can throttle the returned hydraulic oil, so that the hydraulic oil flows back into the hydraulic oil tank 1 at a small flow rate, and the micro-motion of the descending motion of the gantry is realized.
When the opening degree O of the controller meets the condition that O is more than O21 and less than or equal to O22, as shown in the AB section in FIG. 3, the opening degree of the multi-way valve 4 is larger, the throttling effect of the multi-way valve 4 on the returned hydraulic oil is greatly reduced, so that the hydraulic oil can return to the hydraulic oil tank 1 at a large flow rate, and the rapid descending of the portal frame is realized;
when the opening O of the controller meets the condition that O22 is more than O and less than or equal to 100 percent, as shown in a BC section in figure 3, the controller controls the multi-way valve 4 to maintain the maximum opening, and the forklift mast descends at full speed at the maximum descending speed.
In order to improve the rapid descending of the forklift mast, the increasing rate of the opening degree of the multi-way valve 4 is generally set to be smaller when the opening degree O of the controller is less than O21 than when the opening degree O21 of the controller is less than O22.
Of course, the rate of increase of the opening degree of the multiplex valve 4 when the opening degree O of the controller is equal to O21 may be set to be equal to the rate of increase of the opening degree of the multiplex valve 4 when the opening degree O21 < O22 of the controller, as shown in FIG. 8.
In the embodiment, the micro-motion, rapid descending or full-speed descending of the descending action of the door frame can be adjusted by adjusting the opening of the controller, so that the descending requirements of the door frame under different working conditions are met; meanwhile, the speed limiting valve 9 can limit the maximum backflow amount of the gantry during descending, and the action safety is guaranteed.
On the basis of the above embodiment, the port A3 of the multi-way valve 4 is used for communicating with the rodless cavity of the tilt cylinder 6, and the port B3 of the multi-way valve 4 is used for communicating with the rod cavity of the tilt cylinder 6;
when the controller receives the inclination signal, the controller opens the port A3 and controls the two motors 3 to drive the oil pump 2 to rotate, the opening degree of the port A3 and the rotating speed of the motors 3 are gradually increased along with the increase of the opening degree of the controller, so that the hydraulic oil enters the rodless cavity of the inclination oil cylinder 6 through the oil pump 2 and the port A3 of the multi-way valve 4;
when the controller receives the inclination signal and the opening O of the controller is less than or equal to O31, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be greater than the passing flow of the multi-way valve 4;
when the controller receives a lifting signal and the opening O31 of the controller is more than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the passing flow of the multi-way valve 4;
wherein, O31 is a first preset inclination opening degree and is mainly used for dividing a micro-motion area of the inclination motion of the gantry; in order to facilitate the rapid tilting action of the portal frame, O31 is usually set to be less than or equal to 50%, and the specific value of O31 is determined according to factors such as the type of the electric forklift in actual production.
It should be noted that the opening degree of the A3 port and the rotation speed of the motor 3 gradually increase with the increase of the opening degree O of the controller, and when the controller opening degree satisfies 0 < O1 < O2 < 100%, the opening degree O1 'of the A3 port corresponding to the controller opening degree O1 is less than or equal to the opening degree O2' of the A3 port corresponding to the controller opening degree O2, the motor rotation speed n1 corresponding to the controller opening degree O1 is less than or equal to the motor rotation speed n2 corresponding to the controller opening degree O2, and it is not mandatory that O1 '< O2' and n1 < n2 are satisfied for all O1 and O2.
In order to realize the control of the lifting action of the forklift mast, the port A3 of the multi-way valve 4 is communicated with the rodless cavity of the tilt cylinder 6. When the inclination signal received by the controller is a forward inclination signal, the controller controls the pilot oil of the pilot valve to act on the port a3 of the multi-way valve 4; on the contrary, when the inclination signal received by the controller is a backward inclination signal, the controller controls the pilot oil of the pilot valve to act on the port b3 of the multi-way valve 4.
When the forklift mast is in work, a user inputs an inclination signal to the controller, the controller controls the opening of the A3 port communicated with the rodless cavity of the inclination oil cylinder 6 and controls the two motors 3 to drive the oil pump 2 to rotate, the oil pump 2 pumps hydraulic oil in the hydraulic oil tank 1 into the multi-way valve 4, and the hydraulic oil enters the rodless cavity of the inclination oil cylinder 6 through the A3 port of the multi-way valve 4, so that the forklift mast is inclined.
When the opening degree O of the controller is less than or equal to a first preset inclination opening degree O31, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be larger than the accessible flow of the multi-way valve 4, the opening degree of the multi-way valve 4 is used for limiting the flow of the hydraulic oil entering the inclination oil cylinder 6, and the micro-motion of the inclination motion of the gantry can be realized through throttling and speed regulation.
When the opening degree O of the controller meets the condition that O is more than O31 and less than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the accessible flow of the multi-way valve 4, and the rapid action of the inclination action of the gantry is realized through the volume speed regulation of the oil pump 2 at a high rotating speed.
Referring to fig. 4, the broken line ABC is a curve of the opening degree of the port a3 of the multi-way valve 4 according to the opening degree of the controller, and the broken line abcd is a curve of the motor rotation speeds of the two motors 3 driving the two oil pumps 2 according to the opening degree of the controller. And the coordinate axis of the motor rotating speed curve is the ratio of the actual rotating speed of the motor to the maximum preset inclined rotating speed.
It should be noted that, since the oil pump 2 is directly driven by the motor 3, the motor speed curve can also be regarded as the oil pump speed curve of the oil pump 2 driven by the motor.
When the controller opening degree O is less than or equal to O31, the controller controls the opening degree of an A3 port of the multi-way valve 4 to gradually increase along with the increase of the controller opening degree O, and controls the rotating speed of the two oil pumps 2 to gradually increase to a first preset inclined rotating speed n31, and at the moment, the total hydraulic oil flow of the two oil pumps 2 is greater than the accessible flow of an A3 port of the multi-way valve 4;
when the controller opening degree O11 is larger than O and smaller than or equal to O32, the controller controls the opening degree of the port A3 of the multi-way valve 4 to be continuously increased along with the increase of the controller opening degree O, and controls the rotating speeds of the two oil pumps 2 to be gradually increased to the maximum preset inclined rotating speed, and at the moment, the total hydraulic oil flow of the two oil pumps 2 is smaller than the accessible flow of the port A3 of the multi-way valve 4;
when the controller opening O32 is larger than O and is less than or equal to 100%, the controller controls the A3 port of the multi-way valve 4 to maintain the maximum opening, and controls the two oil pumps 2 to maintain the maximum preset inclined rotating speed, and at the moment, the total flow of the hydraulic oil of the two oil pumps 2 is smaller than the accessible flow of the A3 port of the multi-way valve 4.
It should be noted that preset inclination opening degrees such as O31 and O32 in the drawing are determined according to factors such as a vehicle type of the electric forklift in actual production, and the opening degree of the multi-way valve and the motor rotation speed corresponding to the preset lifting opening degree, for example, the opening degree of the multi-way valve corresponding to the point a and the first preset inclination rotation speed n31 corresponding to the ab segment, and the like, can be selected according to an actual working condition of the electric forklift.
In an embodiment, please refer to fig. 9 and 10, the preset lifting opening degrees of the controller are O31=25% and O32=95%, respectively; the maximum preset lifting rotating speed of the oil pump 2 is 1700r/min, and the first preset inclination rotating speed n31 is 450 r/min; the maximum digital quantity of the multi-way valve 4 is 250, and the digital quantity of the multi-way valve corresponding to the point A is 65.
In this embodiment, through the aperture of adjustment controller, can adjust the fine motion of portal slope action or descend rapidly, satisfied the portal slope demand under the different operating modes, improved the fine motion performance of portal slope action to whole energy consumption has been reduced effectively.
Meanwhile, the gantry is rapidly inclined by adopting double-pump confluence, so that the service life of the oil pump 2 and the motor 3 is prolonged, and the reliability of parts in the life cycle of the whole machine is improved.
In order to reduce the overall energy consumption, the total amount of hydraulic oil in the oil pump 2 is normally limited so as not to exceed the amount of hydraulic oil that can pass through the port A3 of the multi-way valve 4 when the opening O of the controller is equal to or less than O31. For example, the total flow of hydraulic oil is
Figure 718343DEST_PATH_IMAGE001
The passing flow rate of the A3 port of the multi-way valve 4 is
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', limit both to satisfy
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≤1.05
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'。
On the basis of the above embodiment, the port a4 of the multi-way valve 4 is used for communicating with the port a of the accessory valve 7 and the rodless cavity of the second accessory cylinder, the ports B4 and a5 of the multi-way valve 4 are both used for communicating with the port B of the accessory valve 7 and the rodless cavity of the first accessory cylinder, and the port B5 of the multi-way valve 4 is used for communicating with the rod cavity of the first accessory cylinder and the rod cavity of the second accessory cylinder;
when the controller receives the accessory action signal, the controller opens the working port of the multi-way valve 4 corresponding to the accessory action signal and controls the two motors 3 to drive the oil pump 2 to rotate, and the opening degree of the working port and the rotating speed of the motors 3 are gradually increased along with the increase of the opening degree O of the controller;
when the controller receives the accessory action signal and O is less than or equal to O41, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be larger than the passing flow of the multi-way valve 4;
when the controller receives the accessory action signal and O is more than O41 and less than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the passing flow of the multi-way valve 4;
wherein, O41 is a first preset accessory action opening degree and is mainly used for dividing a micro-motion area of the door frame accessory action; in order to facilitate quick action of the accessory, O41 is usually set to be less than or equal to 50%, and the specific value of O41 is determined according to factors such as the type of the electric forklift in actual production and the like.
It should be noted that the opening degree of the working port and the rotation speed of the motor 3 both gradually increase with the increase of the opening degree O of the controller, and when the controller opening degree satisfies 0 < O1 < O2 < 100%, the working port opening degree O1 ″ corresponding to the controller opening degree O1 is equal to or less than the working port opening degree O2 ″ corresponding to the controller opening degree O2, and the motor rotation speed n1 corresponding to the controller opening degree O1 is equal to or less than the motor rotation speed n2 corresponding to the controller opening degree O2, and it is not mandatory that O1 ″ < O2 ″ and n1 < n2 are satisfied for all of O1 and O2.
In order to realize the control of the action of the forklift truck accessory, the port A4 of the multi-way valve 4 is communicated with the port A of the accessory valve 7 and a rodless cavity of the second accessory oil cylinder, the ports B4 and A5 of the multi-way valve 4 are connected with the port B of the accessory valve 7 and the rodless cavity of the first accessory oil cylinder, and the port B5 of the multi-way valve 4 is connected with the rod cavity of the first accessory oil cylinder and the rod cavity of the second accessory oil cylinder. The first and second accessory cylinders may be collectively referred to as an accessory cylinder 8.
The accessory action signals specifically comprise a fork left-moving signal, a fork right-moving signal, a fork opening signal, a fork closing signal and the like. When the controller receives the fork left-moving signal, the controller controls the pilot oil of the pilot valve to act on the port a4 of the multi-way valve 4; when the controller receives the fork right movement signal, the controller controls the pilot oil of the pilot valve to act on the port b4 of the multi-way valve 4.
When the controller receives a fork opening signal, the controller controls the pilot oil of the pilot valve to act on the port a5 of the multi-way valve 4; when the controller receives the fork closing signal, pilot oil for controlling the pilot valve acts on the port b5 of the multi-way valve 4.
When the hydraulic oil pump works, a user inputs an accessory action signal to the controller, the controller controls the opening of a working port corresponding to the accessory action and controls the two motors 3 to drive the oil pump 2 to rotate, the oil pump 2 pumps hydraulic oil in the hydraulic oil tank 1 into the multi-way valve 4, and the hydraulic oil enters the accessory valve 7 and the accessory oil cylinder 8 through the working port of the multi-way valve 4 to finish the accessory action.
When the opening degree O of the controller is less than or equal to the first preset accessory action opening degree O41, the controller controls the total flow of the hydraulic oil of the oil pump 2 to be larger than the accessible flow of the multi-way valve 4, the outflow of the hydraulic oil of the multi-way valve 4 is limited by the opening degree of the multi-way valve 4, and the micro-motion of the forklift accessory action can be realized by throttling and speed regulating.
When the opening degree O of the controller meets the condition that O is more than O41 and less than or equal to 100 percent, the controller controls the total flow of the hydraulic oil to be less than the accessible flow of the multi-way valve 4, and the rapid action of the forklift attachment is realized through the volume speed regulation of the oil pump 2 at a high rotating speed.
Referring to fig. 5, the curve ABC is a curve of the opening degree of the multi-way valve 4 with the controller opening degree, and the curve abcd is a curve of the motor rotation speeds of the two motors 3 driving the two oil pumps 2 with the controller opening degree. And the coordinate axis of the motor rotating speed curve is the ratio of the actual rotating speed of the motor to the maximum preset action rotating speed of the accessory.
It should be noted that, since the oil pump 2 is directly driven by the motor 3, the motor speed curve can also be regarded as the oil pump speed curve of the oil pump 2 driven by the motor.
When the controller opening degree O is less than or equal to O41, the controller controls the opening degree of the multi-way valve 4 to gradually increase along with the increase of the controller opening degree O, and controls the rotating speed of the two oil pumps 2 to gradually increase to a first preset accessory action rotating speed n41, and at the moment, the total hydraulic oil flow of the two oil pumps 2 is greater than the accessible flow of the multi-way valve 4;
when the controller opening degree O41 is larger than O and smaller than or equal to O42, the controller controls the opening degree of the multi-way valve 4 to be continuously increased along with the increase of the controller opening degree O, and controls the rotating speeds of the two oil pumps 2 to be gradually increased to the maximum preset accessory action rotating speed, and at the moment, the total hydraulic oil flow of the two oil pumps 2 is smaller than the accessible flow of the A3 port of the multi-way valve 4;
when the controller opening O32 is larger than O and is less than or equal to 100%, the controller controls the A3 port of the multi-way valve 4 to maintain the maximum opening, and controls the two oil pumps 2 to maintain the maximum preset accessory action rotating speed, and at the moment, the total flow of the hydraulic oil of the two oil pumps 2 is smaller than the accessible flow of the A3 port of the multi-way valve 4.
It should be noted that preset inclination opening degrees such as O41 and O42 in the drawing are determined according to factors such as a vehicle type of the electric forklift in actual production, and the opening degree of the multi-way valve and the motor rotation speed corresponding to the preset lifting opening degree, for example, the opening degree of the multi-way valve corresponding to the point a and the first preset inclination rotation speed n41 corresponding to the ab segment, and the like, can be selected according to an actual working condition of the electric forklift.
In an embodiment, please refer to fig. 9 and 10, the preset lifting opening degrees of the controller are O41=45% and O42=95%, respectively; the maximum preset accessory action rotating speed of the oil pump 2 is 950r/min, and the first preset accessory action rotating speed n41 is 450 r/min; the maximum digital value of the multiplex valve 4 is 250, and the multiplex valve digital value corresponding to the point a is 117.
In the embodiment, the micro-motion or rapid decline of the accessory action can be adjusted by adjusting the opening of the controller, so that the accessory requirements under different working conditions are met, the micro-motion performance of the accessory action is improved, and the overall energy consumption is effectively reduced.
Meanwhile, when the accessory rapidly acts, double-pump confluence is adopted, so that the service life of the oil pump 2 and the motor 3 is prolonged, and the reliability of parts in the life cycle of the whole machine is improved.
In order to reduce the overall energy consumption, when the opening O of the controller is less than or equal to O41, the total amount of the hydraulic oil of the oil pump 2 is generally limited to not exceed the flow rate of the multi-way valve 4. For example, the total flow of hydraulic oil is
Figure 735178DEST_PATH_IMAGE003
The passing flow rate of the multi-way valve 4 is
Figure 676589DEST_PATH_IMAGE004
'' to limit both of them to satisfy
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≤1.05
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''。
On the basis of the above embodiment, a pressure sensor 10 for detecting the pump port pressure of the oil pump 2 is arranged between the multi-way valve 4 and the oil pump 2, the pressure sensor 10 is connected with the controller, and when the pump port pressure detected by the pressure sensor 10 is greater than the preset relief pressure, the controller closes the multi-way valve 4 and reduces the rotation speed of the motor 3 until the rotation speed is 0.
The specific type, model, position and installation mode of the pressure sensor 10 are determined according to the maximum value of the pump port pressure in actual production and other factors by referring to the prior art, and are not described herein again.
After the portal action is completed, the system pressure of the hydraulic system can reach the preset overflow pressure, and the pump port pressure of the oil pump 2 is greater than the preset overflow pressure due to the internal pipe loss of the hydraulic system. Therefore, the action of the gantry can be judged to be completed by the pump port pressure of the oil pump 2 being greater than the preset overflow pressure, and the controller controls the multi-way valve 4 and the motor 3 to be closed.
It should be noted that the preset overflow pressures corresponding to different mast actions are different, and the pump port pressure should be greater than the preset overflow pressure corresponding to the current action of the forklift mast.
For example, referring to fig. 1, when the pressure sensor 10 detects that the pressure at the pump port is greater than the preset lifting relief pressure during the lifting operation of the forklift mast, the controller controls the port a1 and the port a2 of the multi-way valve 4 to close, and controls the motor 3 to gradually slow down to 0 r/min.
In this embodiment, whether the gantry movement is completed or not can be accurately judged through the pressure sensor 10, so that the multi-way valve 4 and the motor 3 are closed in time, and the overflow energy loss of the hydraulic system during the gantry movement is effectively reduced.
In order to prevent the transient error of the pump port pressure, it is preferable that the pressure sensor 10 transmits a stop signal to the controller after the pressure sensor 10 detects that the pump port pressure is greater than the preset relief pressure for a preset time.
The preset time is determined according to the requirements in actual production, and is not described herein again.
It should be noted that the first and second of the first and second couplings and the first and second oil pumps mentioned in this document are only used to distinguish the difference of the positions, and do not limit the sequence.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The motion control system of the electric forklift gantry provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (8)

1. The electric forklift gantry motion control system comprises a hydraulic oil tank (1), a controller, a multi-way valve (4), an oil pump (2) and a motor (3), wherein the controller is used for controlling the opening degree of the multi-way valve and the rotating speed of the motor, and is characterized in that at least one opening A of the multi-way valve (4) is communicated with a rodless cavity of a lifting oil cylinder (5), when the controller receives a lifting signal, the opening A is opened by the controller and the motor (3) drives the oil pump (2) to rotate, so that hydraulic oil in the hydraulic oil tank (1) enters the rodless cavity of the lifting oil cylinder (5) through the oil pump (2) and the opening A of the multi-way valve (4), wherein the opening degree of the opening A and the rotating speed of the motor (3) are gradually increased along with the increase of the opening degree O of the controller;
when the controller receives the lifting signal and the opening degree O of the controller is not more than O12, the controller controls the total flow of hydraulic oil of the oil pump (2) to be larger than the passing flow of the multi-way valve (4);
when the controller receives the lifting signal and the opening O12 of the controller is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve (4);
wherein the O12 is a first preset lifting opening degree.
2. The electric forklift mast action control system according to claim 1, characterized in that the number of the oil pumps (2) is two, and the motors (3) are in one-to-one correspondence with the oil pumps (2);
when the controller receives the lifting signal and the opening degree O of the controller is not more than O11, the controller controls the single motor (3) to drive the oil pump (2) to rotate, and the flow rate of hydraulic oil of the single oil pump (2) is larger than the accessible flow rate of the multi-way valve (4);
when the controller receives the lifting signal and the opening degree O11 of the controller is larger than O and is not larger than O12, the controller controls the two motors (3) to drive the oil pumps (2) to rotate, and the total hydraulic oil flow of the two oil pumps (2) is larger than the accessible flow of the multi-way valve (4);
when the controller receives the lifting signal and the opening O12 of the controller is larger than O and is smaller than or equal to 100%, the controller controls the two motors (3) to drive the oil pumps (2) to rotate, and the total flow of hydraulic oil of the two oil pumps (2) is smaller than the accessible flow of the multi-way valve (4);
and the O11 is a second preset lifting opening, and O11 is less than O12.
3. The electric forklift gantry motion control system according to claim 2, wherein a speed limiting valve (9) is arranged between a rodless cavity of the lifting cylinder (5) and the multi-way valve (4), and when the controller receives a descending signal, the controller closes the motor (3) and opens the port A corresponding to the lifting cylinder (5), so that the hydraulic oil flows back into the hydraulic oil tank (1) through the speed limiting valve (9) and the multi-way valve (4);
the opening degree of the port A corresponding to the lifting oil cylinder (5) is gradually increased along with the increase of the opening degree of the controller, and when the opening degree O of the controller is not more than O21, the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder (5) is smaller than the increase rate of the opening degree of the port A corresponding to the lifting oil cylinder (5) when the opening degree O21 of the controller is larger than O and not more than O22;
wherein the O21 is a first preset descending opening degree, and the O22 is a second preset descending opening degree.
4. The electric forklift mast operation control system according to claim 2, characterized in that the port a3 of the multi-way valve (4) is used for communicating with the rodless chamber of the tilt cylinder (6), and the port B3 of the multi-way valve (4) is used for communicating with the rod chamber of the tilt cylinder (6);
when the controller receives a tilt signal, the controller opens the A3 port and controls the two motors (3) to drive the oil pump (2) to rotate, and the opening degree of the A3 port and the rotating speed of the motors (3) are gradually increased along with the increase of the opening degree of the controller, so that the hydraulic oil enters a rodless cavity of the tilt cylinder (6) through the oil pump (2) and the A3 port of the multi-way valve (4);
when the controller receives an inclination signal and the opening degree O of the controller is less than or equal to O31, the controller controls the total flow of the hydraulic oil of the oil pump (2) to be greater than the passing flow of the multi-way valve (4);
when the controller receives the lifting signal and the opening O31 of the controller is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve (4);
wherein the O31 is a first preset inclination opening.
5. The electric forklift mast operation control system according to claim 2, wherein the port a4 of the multi-way valve (4) is used for communicating with the port a of the accessory valve (7) and the rodless chamber of the second accessory cylinder, the ports B4 and a5 of the multi-way valve (4) are both used for communicating with the port B of the accessory valve (7) and the rodless chamber of the first accessory cylinder, and the port B5 of the multi-way valve (4) is used for communicating with the rod chamber of the first accessory cylinder and the rod chamber of the second accessory cylinder;
when the controller receives an accessory action signal, the controller opens a working opening of the multi-way valve (4) corresponding to the accessory action signal and controls the two motors (3) to drive the oil pump (2) to rotate, and the opening of the working opening and the rotating speed of the motors (3) are gradually increased along with the increase of the opening O of the controller;
when the controller receives the accessory action signal and O is less than or equal to O41, the controller controls the total flow of the hydraulic oil of the oil pump (2) to be greater than the passing flow of the multi-way valve (4);
when the controller receives the accessory action signal and O41 is larger than O and is less than or equal to 100%, the controller controls the total flow of the hydraulic oil to be smaller than the passing flow of the multi-way valve (4);
wherein the O41 is a first preset accessory operation opening.
6. The electric forklift mast action control system according to any one of claims 1 to 5, characterized in that a pressure sensor (10) for detecting the pump port pressure of the oil pump (2) is arranged between the multi-way valve (4) and the oil pump (2), the pressure sensor (10) is connected with the controller, and when the pump port pressure detected by the pressure sensor (10) is greater than a preset relief pressure, the controller closes the multi-way valve (4) and reduces the rotation speed of the motor (3) to 0.
7. The electric forklift mast operation control system according to claim 6, characterized in that the T1 port of the multi-way valve (4) is communicated with the hydraulic oil tank (1) through an oil return filter (12).
8. The electric fork lift mast action control system of claim 7, characterized in that the Pp port of the multi-way valve (4) is connected with an accumulator (11).
CN202210413038.6A 2022-04-20 2022-04-20 Electric fork-lift portal motion control system Active CN114506800B (en)

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CN117967622A (en) * 2024-04-01 2024-05-03 杭叉集团股份有限公司 Forklift attachment hydraulic system and control method thereof

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CN114955944A (en) * 2022-05-31 2022-08-30 杭叉集团股份有限公司 Fork truck equipment speed control hydraulic system
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CN117967622A (en) * 2024-04-01 2024-05-03 杭叉集团股份有限公司 Forklift attachment hydraulic system and control method thereof
CN117967622B (en) * 2024-04-01 2024-06-11 杭叉集团股份有限公司 Forklift attachment hydraulic system and control method thereof

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