Control method of reach forklift

Abstract

The invention discloses a control method of a reach forklift, and particularly relates to the technical field of forklifts, which comprises the following steps of: carrying out lifting, descending, forward moving and backward moving operations on a pallet fork, and independently setting a segmented control parameter of an opening and closing state of an electromagnetic valve and a segmented control parameter of a starting and stopping state of a pump motor for each action; when corresponding switches are operated, if the rotating speed of the pump motor is gradually increased, the accelerated speed of the rotating speed of the pump motor is gradually increased; the change rate of the valve port current of the electromagnetic valve is gradually increased; when the controlled switch is released, the deceleration of the rotating speed of the pump motor is gradually reduced; and the change rate of the electromagnetic valve port current is gradually reduced. The control method is simple in design, safe and reliable, the control method is designed according to a three-section mode, a multi-section segmentation mode can be carried out according to different gantry heights, the characteristics of a pump motor and the characteristics of an electromagnetic valve, the control comfort and safety of the reach forklift are improved, and the control method can be borrowed on other vehicle types.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, and more particularly, to a control method for a reach forklift. Background Art

[0002] It is known that reach forklifts are an important type of industrial forklift, which is widely used in scenarios such as warehousing and logistics, manufacturing, etc.; since reach forklifts can be equipped with high masts, they are widely used in high-standard warehouses; however, in actual use, because the masts of reach forklifts are relatively high, some are more than ten meters high, so when operating the forks on the mast at high cargo positions, they will be affected by motor response, switching impact of solenoid valves, low efficiency and instability of oil pumps, and tension of oil pipes. As a result, the mast drives the forks to lift, lower, and move forward and backward, which will be impacted, causing the forks to shake and even cause safety accidents.

[0003] In order to solve this potential safety hazard, a control method for a reach forklift is proposed as a further improvement to improve the safety of customer use. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a control method for a reach forklift to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a control method for a reach forklift, comprising the following operating steps:

[0006] S1: Set up the connections of the reach truck components to ensure that the forks on the mast can lift, lower, move forward and backward;

[0007] S2: For the lifting, lowering, forward and backward operations of the fork, the segmented control parameters of the solenoid valve opening and closing state and the segmented control parameters of the pump motor start and stop state are independently set for each action;

[0008] S3: If the fork is lifted, moved forward or moved backward, enter S4;

[0009] If the fork is lowered, proceed to S5;

[0010] If there is no operation, return to S2;

[0011] S4: When the corresponding switch is operated, the speed of the pump motor gradually increases, and the acceleration of the pump motor speed gradually increases; the current of the solenoid valve port gradually increases, and the rate of change of the solenoid valve port current gradually increases;

[0012] When the controlled switch is released, the speed of the pump motor gradually decreases, and the deceleration of the pump motor speed gradually decreases; the current of the solenoid valve port gradually decreases, and the rate of change of the solenoid valve port current gradually decreases; when the speed of the pump motor is 0 or the solenoid valve port current is 0, return to S3;

[0013] S5: When the corresponding switch is operated, the pump motor does not work; the current at the solenoid valve port gradually increases, and the rate of change of the current at the solenoid valve port gradually increases;

[0014] When the controlled switch is released, the pump motor does not work; the current at the solenoid valve port gradually decreases, and the rate of change of the solenoid valve port current gradually decreases; when the solenoid valve port current is 0, return to S3.

[0015] Furthermore, in the above S5, the pump motor does not participate in the work, and the flow rate of the hydraulic oil is controlled by the magnitude of the current at the valve port of the solenoid valve.

[0016] Furthermore, in S2, the segmented control parameters of the opening and closing states of the solenoid valve are set to three segments.

[0017] Furthermore, in S2, the segmented control parameters of the pump motor start and stop states are set to three segments.

[0018] Furthermore, in S2, the segmented control parameters of the opening and closing states of the solenoid valve include the rate of change of the valve port current of the solenoid valve.

[0019] Furthermore, in S2, the segmented control parameters of the pump motor start and stop state include the acceleration and deceleration of the pump motor speed.

[0020] Technical effects and advantages of the present invention:

[0021] Compared with the existing technology, the present invention has a simple design, is safe and reliable, and the control method is designed in a three-stage manner. It can be divided into multiple stages according to different mast heights, pump motor characteristics and solenoid valve characteristics, which helps to improve the operating comfort and safety of reach forklifts and can be borrowed on other models. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Flowchart of the present invention.

[0023] Figure 2 The present invention relates to a circuit diagram of a reach forklift.

[0024] The accompanying drawings are:

[0025] 2. Solenoid valve;

[0026] 21. Lifting electromagnetic coil; 22. Lowering electromagnetic coil; 23. Forward electromagnetic coil;

[0027] 24. Move back the electromagnetic coil;

[0028] 3. Thumb switch;

[0029] 31. Lift thumb switch; 32. Lower thumb switch; 33. Forward thumb switch;

[0030] 34. Move the thumb switch back;

[0031] 4. Pressure sensor; 5. Valve controller; 6. Pump motor; 7. Power battery; 8. Key switch;

[0032] 9. Pump controller;

[0033] 10. Main contactor; 101. Main contactor switch; 102. Main contactor coil;

[0034] 11. Fuse A; 12. Fuse B. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] A control method for a reach forklift includes the following steps: Figure 2 A reach forklift shown, a reach forklift includes: a solenoid valve 2, a thumb switch 3, a pressure sensor 4, a valve controller 5, a pump motor 6, a power battery 7, a key switch 8, a pump controller 9, a main contactor 10, a fuse A11, and a fuse B12;

[0037] The thumb switches 3 include a lifting thumb switch 31 , a lowering thumb switch 32 , a forward thumb switch 33 and a backward thumb switch 34 ;

[0038] The main contactor 10 includes: a main contactor switch 101 and a main contactor coil 102;

[0039] Specific connection embodiment: the positive electrode of the power battery 7 is connected to one end of the key switch 8, and the other end of the key switch 8 is fixedly connected to one end of the main contactor switch 101, the key end of the pump controller 9, one end of the main contactor coil 102 and one end of the fuse B12;

[0040] The other end of the main contactor coil 102 is connected to the main contactor terminal of the pump controller 9;

[0041] The other end of the main contactor switch 101 is connected to the positive terminal of the pump controller 9 through the fuse A11;

[0042] The other end of the fuse B12 is connected to the key end of the valve controller 5 and the positive end of the valve controller 5 respectively;

[0043] The negative terminal of the pump controller 9 and the negative terminal of the valve controller 5 are both connected to the negative terminal of the power battery 7;

[0044] The pump controller 9 is connected to the pressure sensor 4 for signal connection;

[0045] The valve controller 5 is respectively connected to the lifting thumb switch 31, the lowering thumb switch 32, the forward thumb switch 33, the backward thumb switch 34 and the solenoid valve 2;

[0046] The solenoid valve 2 includes a valve body and a valve core; the valve core is connected to the valve controller 5, and the valve core is an electromagnetic coil that controls the opening size of the valve body by varying the magnitude of the current; the opening size of the valve body directly affects the speed and maneuverability of the gantry, and the opening and closing of the valve body affect the impact of the gantry pipeline and prolong the time it takes for the cargo to stop. The main reason is that when the valve body is instantly closed, although the pump motor 6 stops rotating, the instantaneous closure causes an impact on the oil circuit in the gantry pipe, and coupled with the tension in the oil pipe, the gantry will move up and down; when the valve body is closed with a hysteresis, even if the thumb switch 3 is released, the gantry will still move and will not stop immediately;

[0047] Therefore, the present inventors provide a method for solving the above problem, which requires segmented control of the response between the solenoid valve 2 and the pump motor 6.

[0048] The valve body includes: a lifting valve body, a lowering valve body, a forward moving valve body, and a backward moving valve body; the solenoid valve 2 further includes: a lifting electromagnetic coil 21, a lowering electromagnetic coil 22, a forward moving electromagnetic coil 23, and a backward moving electromagnetic coil 24; and the lifting electromagnetic coil 21, the lowering electromagnetic coil 22, the forward moving electromagnetic coil 23, and the backward moving electromagnetic coil 24 are all connected to corresponding ports of the valve controller 5;

[0049] The signal terminals U, V, and W of the pump controller 9 are connected to the signal terminals of the pump motor 6 respectively;

[0050] Among them, the power battery 7 provides the power source for the entire vehicle; when the key switch 8 is turned on, the main contactor coil 102 is turned on, and the pump controller 9 and the valve controller 5 are powered on for self-testing. That is, the entire vehicle performs a self-test. If the pump controller 9 and the valve controller 5 are found to be normal, the main contactor switch 101 is pulled in. At this time, the power of the power battery 7 is transmitted to the pump controller 9 and the valve controller 5 through the fuse A11 and the fuse B12;

[0051] Among them, the output shaft of the pump motor 6 is connected to the output shaft of the oil pump, and the output pipeline of the oil pump is connected to each pipeline of the mast through the corresponding solenoid valve 2; then the pump controller 9 controls the speed of the oil pump, and the valve controller 5 controls the opening and closing of the solenoid valve 2. At the same time, the valve controller 5 obtains the input and output of the thumb switch 3.

[0052] Among them, the thumb switch 3 includes lifting and lowering functions and forward and backward movement functions; when the thumb switch 3 is turned, the pump motor 6 will rotate, thereby driving the oil pump to rotate. At this time, hydraulic oil will enter each solenoid valve 2 through the oil pump, and the solenoid valve 2 will be connected to each pipeline of the gantry, thereby driving the gantry to lift, lower, move forward or backward.

[0053] The valve controller 5 uses the triggering of the lifting thumb switch 31 to turn on the lifting electromagnetic coil 21, controlling the oil pump to drive the fork on the mast to lift;

[0054] The valve controller 5 uses the triggering of the descending thumb switch 32 to turn on the descending electromagnetic coil 22, and controls the oil pump to drive the forks on the mast to descend;

[0055] The valve controller 5 uses the triggering of the forward thumb switch 33 to turn on the forward electromagnetic coil 23, and controls the oil pump to drive the forks on the mast to move forward;

[0056] The valve controller 5 uses the triggering of the rearward movement thumb switch 34 to turn on the rearward movement electromagnetic coil 24, and controls the oil pump to drive the forks on the mast to move rearward;

[0057] Among them, the lifting thumb switch 31 and the lowering thumb switch 32 can be used as one component but with different output voltages; similarly, the forward thumb switch 33 and the backward thumb switch 34 can be used as one component but with different output voltages;

[0058] Among them, the pressure sensor 4 can only distinguish whether the vehicle is empty or fully loaded. For different empty and full loads, the valve core current of the solenoid valve 2 is different, but the control method of empty and full load is the same;

[0059] As attached Figure 1 A control method for a reach forklift shown includes the following steps:

[0060] S1: Set up the connections of the reach truck components to ensure that the forks on the mast can lift, lower, move forward and backward;

[0061] S2: For the lifting, lowering, forward and backward operations of the fork, the segmented control parameters of the opening and closing states of the solenoid valve 2 and the segmented control parameters of the start and stop states of the pump motor 6 are independently set for each action;

[0062] Among them, since the opening and closing states of the solenoid valve 2 and the pump motor 6 need to be controlled in sections, the corresponding parameters are set in a manner that they are first slow and then fast when opening, and first fast and then slow when closing;

[0063] S3: If the fork is lifted, moved forward or moved backward, enter S4;

[0064] If the fork is lowered, proceed to S5;

[0065] If there is no operation, return to S2;

[0066] The specific embodiments are:

[0067] 1. When the gantry is lifted, the valve core current of the solenoid valve 2 is controlled in three sections, and the currents of the valve port are EVP1, EVP2, and EVP3 respectively; the speed of the pump motor 6 is controlled in three sections, and the speeds are P1, P2, and P3 respectively.

[0068] That is: when the thumb switch 3 is operated to lift, the speed of the pump motor 6 increases from P1 to P2, and then to P3. The acceleration of P1 is less than that of P2, and the acceleration of P2 is less than that of P3. The current of the valve port gradually increases from EVP1 to EVP2, and then to EVP3. The rate of change of current EVP1 is less than that of EVP2, and EVP2 is less than that of EVP3.

[0069] When the thumb switch 3 is released, the speed of the pump motor 6 decreases from P3 to P2, and then to P1. The deceleration of P3 is greater than that of P2, and the deceleration of P2 is greater than that of P1. The current at the valve port gradually decreases from EVP3 to EVP2, and then to EVP1. The current change rate EVP3 is greater than EVP2, and EVP2 is greater than EVP1.

[0070] 2. When the gantry descends, the valve core current of the solenoid valve 2 is controlled in three sections, and the currents of the valve ports are EVP4, EVP5, and EVP6 respectively; the pump motor 6 does not participate in the work (setting the parameters is meaningless);

[0071] When thumb switch 3 is lowered, pump motor 6 is not involved in the operation. Therefore, the flow rate is controlled solely by the current flowing through the port of solenoid valve 2. The port current changes from EVP4 to EVP5 and then to EVP6. The rate of change of current in EVP4 is smaller than that in EVP5, which in turn is smaller than that in EVP6.

[0072] When the thumb switch 3 is released, the current at the valve port changes from EVP6 to EVP5 and then to EVP4. The current change rate EVP6 is greater than EVP5, and EVP5 is greater than EVP4.

[0073] 3. When the gantry moves forward, the valve core current of the solenoid valve 2 is controlled in three sections, and the currents of the valve ports are EVP7, EVP8, and EVP9 respectively; the speed of the pump motor 6 is controlled in three sections, and the speeds are P7, P8, and P9 respectively.

[0074] When the thumb switch 3 is moved forward, the speed of the pump motor 6 increases from P7 to P8, and then to P9. The acceleration of P7 is smaller than that of P8, and the acceleration of P8 is smaller than that of P9. The current of the valve port gradually increases from EVP7 to EVP8, and then to EVP9. The rate of change of current EVP7 is smaller than that of EVP8, and EVP8 is smaller than that of EVP9.

[0075] When the thumb switch 3 is released, the speed of the pump motor 6 changes from P9 to P8, and then to P7. The deceleration of P9 is greater than that of P8, and the deceleration of P8 is greater than that of P7. The current at the valve port gradually decreases, and the current size at the valve port changes from EVP9 to EVP8, and then to EVP7. The current change rate EVP9 is greater than EVP8, and EVP8 is greater than EVP7.

[0076] 4. When the mast moves backward, the valve core current of the solenoid valve 2 is controlled in three stages, and the valve port currents are EVP10, EVP11, and EVP12 respectively. The speed of the pump motor 6 is controlled in three stages, and the speeds are P10, P11, and P12 respectively.

[0077] When the thumb switch 3 is moved backward, the speed of the pump motor 6 changes from P10 to P11, and then to P12. The acceleration of P10 is less than that of P11, and the acceleration of P11 is less than that of P12. The current at the valve port changes from EVP10 to EVP11, and then to EVP12. The rate of change of current EVP10 is less than that of EVP11, and EVP11 is less than that of EVP12.

[0078] When thumb switch 3 is released, the speed of pump motor 6 changes from P12 to P11 and then to P10. The deceleration of P12 is greater than that of P11, and the deceleration of P11 is greater than that of P10. The current at the valve port changes from EVP12 to EVP11 and then to EVP10. The rate of change of current EVP12 is greater than that of EVP11, and EVP11 is greater than that of EVP10.

[0079] S4: When the corresponding switch is operated, the speed of the pump motor 6 gradually increases, and the acceleration of the speed of the pump motor 6 gradually increases; the current at the valve port of the solenoid valve 2 gradually increases, and the rate of change of the current at the valve port of the solenoid valve 2 gradually increases;

[0080] When the controlled switch is released, the speed of the pump motor 6 gradually decreases, and the deceleration of the speed of the pump motor 6 gradually decreases; the current at the valve port of the solenoid valve 2 gradually decreases, and the rate of change of the current at the valve port of the solenoid valve 2 gradually decreases; when the speed of the pump motor 6 is 0 or the current at the valve port of the solenoid valve 2 is 0, return to S3;

[0081] S5: When the corresponding switch is operated, the pump motor 6 does not participate in the work; the current of the valve port of the solenoid valve 2 gradually increases, and the rate of change of the current of the valve port of the solenoid valve 2 gradually increases;

[0082] When the controlled switch is released, the pump motor 6 does not work; the current at the valve port of the solenoid valve 2 gradually decreases, and the rate of change of the current at the valve port of the solenoid valve 2 gradually decreases; when the current at the valve port of the solenoid valve 2 is 0, return to S3.

[0083] In a preferred embodiment, as shown in the attached Figure 1 As shown, in S5, the pump motor 6 does not participate in the work, and the flow rate of the hydraulic oil is controlled by the magnitude of the valve port current of the solenoid valve 2.

[0084] In a preferred embodiment, as shown in the attached Figure 1 As shown, in S2, the segmented control parameters of the opening and closing states of the solenoid valve 2 are set to three stages.

[0085] In a preferred embodiment, as shown in the attached Figure 1 As shown, in S2, the segmented control parameters of the start and stop states of the pump motor 6 are set to three stages.

[0086] In a preferred embodiment, as shown in the attached Figure 1 As shown, in S2, the segmented control parameters of the opening and closing states of the solenoid valve 2 include the rate of change of the valve port current of the solenoid valve 2.

[0087] In a preferred embodiment, as shown in the attached Figure 1 As shown, in S2 , the segmented control parameters of the start and stop states of the pump motor 6 include the acceleration and deceleration of the rotational speed of the pump motor 6 .

[0088] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0089] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a reach forklift, characterized in that: The steps are as follows: S1: Set up the connections of the reach truck components to ensure that the forks on the mast can lift, lower, move forward and backward; S2: For the lifting, lowering, forward and backward operations of the fork, the segmented control parameters of the solenoid valve opening and closing state and the segmented control parameters of the pump motor start and stop state are independently set for each action; S3: If the fork is lifted, moved forward or moved backward, enter S4; If the fork is lowered, proceed to S5; If there is no operation, return to S2; S4: When the corresponding switch is operated, the speed of the pump motor gradually increases, and the acceleration of the pump motor speed gradually increases; the current of the solenoid valve port gradually increases, and the rate of change of the solenoid valve port current gradually increases; When the controlled switch is released, the speed of the pump motor gradually decreases, and the deceleration of the pump motor speed gradually decreases; the current of the solenoid valve port gradually decreases, and the rate of change of the solenoid valve port current gradually decreases; when the speed of the pump motor is 0 or the solenoid valve port current is 0, return to S3; S5: When the corresponding switch is operated, the pump motor does not work; the current at the solenoid valve port gradually increases, and the rate of change of the current at the solenoid valve port gradually increases; When the controlled switch is released, the pump motor does not work; the current at the solenoid valve port gradually decreases, and the rate of change of the solenoid valve port current gradually decreases; when the solenoid valve port current is 0, return to S3.

2. The control method of a reach truck according to claim 1, characterized in that: In the above-mentioned S5, the pump motor does not participate in the work, and the flow rate of the hydraulic oil is controlled by the magnitude of the current at the valve port of the solenoid valve.

3. The control method of a reach truck according to claim 1, characterized in that: In the above-mentioned S2, the segmented control parameters of the opening and closing states of the solenoid valve are set to three segments.

4. The control method of a reach truck according to claim 1, wherein: In the above-mentioned S2, the segmented control parameters of the pump motor start and stop states are set to three segments.

5. The control method of a reach truck according to claim 3, characterized in that: In the above S2, the segmented control parameters of the opening and closing states of the solenoid valve include the rate of change of the valve port current of the solenoid valve.

6. The control method of a reach truck according to claim 4, characterized in that: In the above S2, the segmented control parameters of the pump motor start and stop state include the acceleration and deceleration of the pump motor speed.

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