Forklift gearbox assembly based on electromagnetic proportional valve and hydraulic gear shifting control system

Abstract

The invention discloses a forklift gearbox assembly based on an electromagnetic proportional valve and a hydraulic gear shifting control system. The forklift gearbox assembly comprises a micro-reverse gear table look-up module, a micro-forward gear table look-up module, a micro-pedal angle table look-up module, a first selection switch, a second selection switch and a third selection switch. A gearbox oil pan temperature input interface is connected with the input port of the inching-backward gear table look-up module and the input port of the inching-forward gear table look-up module. The micro-motion pedal input interface is connected with the input end of the micro-motion pedal angle table look-up module, and the output end of the micro-motion pedal angle table look-up module is connected with the input port of the micro-motion-reverse gear table look-up module and the input port of the micro-motion-forward gear table look-up module; the output end of the reverse gear input interface and the output end of the inching-reverse gear table look-up module are connected with the input end of the first selection switch; the output end of the forward gear input interface and the output end of the inching-forward gear table look-up module are connected with the input end of the second selection switch; the output end of the second selection switch is connected with the input end of the first selection switch; and the output end of the first selection switch is connected with the input end of the third selection switch, the output end of the third selection switch outputs a control current value of the electromagnetic proportional valve, gear engagement, reversing and micro-motion function execution are more accurate and smooth in function, and gear shifting impact is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic shift systems, and in particular to a forklift gearbox assembly and a hydraulic shift control system based on an electromagnetic proportional valve. Background Art

[0002] The use scenario determines that the forklift needs to perform frequent gear shifting and reversing operations during the actual working process. In some working situations, the micro-motion function also needs to be used frequently. Traditional hydraulic transmission forklifts usually use mechanical switch valves or electromagnetic switch valves with several positions and several passes to achieve gear shifting and reversing operations, and additional micro-motion valves are required to achieve the micro-motion function. Due to their characteristics, traditional mechanical structures or electromagnetic switch valves will inevitably produce certain gear shifting shocks when the forklift cuts into gear or changes direction. In addition, coupled with the influence of the driver's operating experience, it will cause additional impact and wear on the gearbox clutch, affecting the vehicle performance, reliability and service life.

[0003] In the prior art, for example, the invention patent with patent publication number CN117869488A discloses a clutch control device and a clutch control method. In the patent, the shift control valve is replaced by a solenoid valve, and the shift control valve is used to replace the traditional pilot switch solenoid valve. The oil pressure in the control oil chamber of the clutch can be directly adjusted by adjusting the current of the shift control valve to reduce the shift shock and improve the shift response speed. However, the micro-motion function cannot be accurately controlled. Summary of the invention

[0004] The technical problem to be solved by the present invention is to realize accurate hydraulic control of the micro-motion function of a forklift.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A control system for a forklift gearbox assembly based on an electromagnetic proportional valve includes: an inching-reverse gear lookup module 10, an inching-forward gear lookup module 20, an inching pedal angle lookup module 30, a first selection switch 41, a second selection switch 42, and a third selection switch 43.

[0007] Among them, the gearbox oil pan temperature input interface 51 is connected to the input ports of the inching-reverse gear lookup module 10 and the inching-forward gear lookup module 20;

[0008] The inching pedal input interface 52 is connected to the input end of the inching pedal angle table lookup module 30, and the output end of the inching pedal angle table lookup module 30 is respectively connected to the input ports of the inching-reverse gear table lookup module 10 and the inching-forward gear table lookup module 20;

[0009] The reverse gear input interface 53 and the output end of the inching-reverse gear lookup module 10 are connected to the input end of the first selection switch 41;

[0010] The forward gear input interface 54 and the output end of the inching-forward gear table lookup module 20 are connected to the input end of the second selection switch 42;

[0011] The output end of the second selection switch 42 is connected to the input end of the first selection switch 41; and the output end of the first selection switch 41 is connected to the input end of the third selection switch 43, and the output end of the third selection switch 43 outputs the electromagnetic proportional valve control current value.

[0012] In one embodiment of the present invention, the inching pedal angle table lookup module 30 is associated with an angle and voltage curve table compiled according to the characteristics of the angle sensor, and outputs the pedal opening corresponding to the oil pressure.

[0013] In one embodiment of the present invention, the inching-reverse gear table lookup module 10 includes a first first-order table lookup module 11 and a first second-order table lookup module 12;

[0014] The output end of the inching pedal angle table lookup module 30 is connected to the input end of the first first-order table lookup module 11; the transmission oil pan temperature input interface 51 and the output end of the first first-order table lookup module 11 are connected to the input end of the first second-order table lookup module 12, and the output end of the first second-order table lookup module 12 is connected to the input end of the first selection switch 41;

[0015] The first-order table lookup module 11 is associated with a curve corresponding to the inching pedal opening voltage and the hydraulic system oil pressure compiled according to the test, and outputs the system oil pressure corresponding to the reverse gear position;

[0016] The first and second order table lookup modules 12 are associated with the corresponding curves of oil temperature, oil pressure and output current compiled based on the test and the characteristics of the electromagnetic proportional valve, and the output reverse gear position corresponds to the electromagnetic proportional valve control current.

[0017] In one embodiment of the present invention, the inching-forward gear table lookup module 20 includes a second first-order table lookup module 21 and a second second-order table lookup module 22;

[0018] The output end of the inching pedal angle table lookup module 30 is connected to the input end of the second first-order table lookup module 21; the transmission oil pan temperature input interface 51 and the output end of the second first-order table lookup module 21 are connected to the input end of the second second-order table lookup module 22, and the output end of the second second-order table lookup module 22 is connected to the input end of the second selection switch 42;

[0019] The second first-order table lookup module 21 is associated with a curve corresponding to the inching pedal opening voltage and the hydraulic system oil pressure compiled according to the test, and outputs the system oil pressure corresponding to the forward gear position;

[0020] The second second-order table lookup module 22 is associated with a curve corresponding to oil temperature, oil pressure and output current compiled based on experiments and electromagnetic proportional valve characteristics, and outputs a control current of the electromagnetic proportional valve corresponding to the forward gear position.

[0021] In one embodiment of the present invention, the control system of the forklift gearbox assembly also includes a calibration and overshoot mode current loop module 61 and a calibration and overshoot mode input module 62; and the calibration and overshoot mode current loop module 61 and the calibration and overshoot mode input module 62 are connected to the input end of the third selection switch 43.

[0022] In one embodiment of the present invention, the control logic of the reverse inching condition is:

[0023] The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal; the voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module 30, and then the system oil pressure value corresponding to the reverse gear position under the corresponding inching pedal opening is found through the first first-order lookup module 11; the temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the first first-order lookup module 11, and finds the electromagnetic proportional valve control current value corresponding to the reverse gear position through the first second-order lookup module 12;

[0024] At this time, the reverse gear signal corresponding to the first selection switch 41 is set to "1", the forward gear signal of the second selection switch 42 is set to "0", and the calibration and overshoot mode corresponding to the third selection switch 43 are set to "0"; after judgment by the second selection switch 42, the logic flow goes down, after judgment by the first selection switch 41, the logic flow goes up, and after judgment by the third selection switch 43, the logic flow goes down.

[0025] In one embodiment of the present invention, the forward inching working condition control logic route is:

[0026] The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal; the voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module 30, and then the system oil pressure value corresponding to the forward gear under the corresponding inching pedal opening is found through the second first-order lookup module 21; the temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the second first-order lookup module 21, and finds the electromagnetic proportional valve control current value corresponding to the forward gear through the second second-order lookup module 22;

[0027] At this time, the forward gear signal corresponding to the second selection switch 42 is set to "1", the reverse gear signal corresponding to the first selection switch 41 is set to "0", and the calibration and overshoot mode corresponding to the third selection switch 43 are set to "0"; after judgment by the second selection switch 42, the logic flow goes on the upper path, after judgment by the first selection switch 41, the logic flow goes off the lower path, and after judgment by the third selection switch 43, the logic flow goes off the lower path.

[0028] In one embodiment of the present invention, the control logic of the calibration and overshoot modes is as follows:

[0029] At this time, the calibration and overshoot mode is entered, the reverse gear signal corresponding to the first selection switch 41 is set to "0", the forward gear signal corresponding to the second selection switch 42 is set to "0", the calibration and overshoot mode input module 62 is set to "1", the logic flow is judged by the first selection switch 41, the logic flow is judged by the second selection switch 42, and the logic flow is judged by the third selection switch 43.

[0030] The calibration and overshoot mode input module 62 outputs the calibration and overshoot current according to the current curve preset in the calibration and overshoot mode current loop module 61, and outputs it through the third selection switch 43. At this time, the solenoid proportional valve works according to the current curve preset in the calibration and overshoot mode current loop module 61.

[0031] A forklift hydraulic shift control system, using the control system of the forklift gearbox assembly based on the electromagnetic proportional valve described above, comprising: an oil storage tank 1, a filter 2, an oil supply pump 3, an electromagnetic proportional valve 4, a forward gear clutch 5, a reverse gear clutch 6 and a main pressure regulating valve 7;

[0032] Wherein, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve is communicatively connected with the electromagnetic proportional valve 4;

[0033] The oil in the oil storage tank 1 is filtered by the filter 2, and the transmission oil is pressurized by the oil supply pump 3 and then divided into two paths at the outlet; after the main pressure regulating valve 7 adjusts the pressure, it is input into the oil inlet channel at the bottom of the electromagnetic proportional valve 4;

[0034] The control system of the forklift gearbox assembly based on the electromagnetic proportional valve accurately controls the movement of the electromagnetic proportional valve 4 through the output current, thereby controlling the oil pressure of the forward gear clutch 5 and the reverse gear clutch 6 to realize the functions of each gear and micro-motion.

[0035] In one embodiment of the present invention, in the neutral state, the electromagnetic proportional valve 4 does not work, the valve core of the electromagnetic proportional valve 4 is in the middle position, and both the forward gear and the reverse gear clutches have no oil pressure and are not engaged;

[0036] In the forward gear, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the gear position signal, proportionally increases the electromagnetic coil current of the electromagnetic proportional valve 4 at the S1 end, the valve core moves toward the S1 end, the main oil circuit is connected with the forward gear clutch cavity, and the oil pressure is proportionally established, the forward gear clutch 5 is engaged, and the forward gear power transmission is realized;

[0037] If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S1 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the forward gear clutch cavity oil circuit, and the forward gear clutch cavity is depressurized to realize the inching function in the forward gear mode. If the inching pedal is released at this time, the forward gear is restored;

[0038] In the reverse gear, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the gear signal, increases the electromagnetic coil current of the electromagnetic proportional valve 4 at the S2 end proportionally, the valve core moves toward the S2 end, the main oil circuit is connected with the reverse gear clutch cavity, the oil pressure is proportionally established, the reverse gear clutch is engaged, and the reverse gear power transmission is realized;

[0039] If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S2 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the reverse gear clutch cavity oil circuit, and the reverse gear clutch cavity is depressurized to realize the inching function in the reverse gear mode. If the inching pedal is released at this time, the reverse gear is restored.

[0040] Compared with the prior art, the beneficial effects of the present invention are: in view of the shortcomings of the existing small-tonnage forklift hydraulic transmission shifting system, a three-position four-way electromagnetic proportional valve is used to replace the traditional micro-valve, buffer valve, and gear valve to realize the functions of shifting and micro-movement, and a proportional valve control unit is used to control the solenoid valve to achieve more precise hydraulic control.

[0041] The present invention replaces the gear constant pressure valve, buffer valve, reversing solenoid valve and micro valve in the traditional structure with an electromagnetic proportional valve, which greatly reduces the amount of hardware, makes the entire system structure more streamlined and more compact in size, and is conducive to the layout of the entire vehicle.

[0042] The present invention uses an electromagnetic proportional valve to make the gear engagement, reversing and micro-motion functions more precise and smooth, reduce gear shifting shock, reduce friction plate wear and minimize the possible risk of friction plate ablation, extend the service life of components, reduce the economic loss and operating risk of the vehicle, and improve the operability and comfort of the vehicle.

[0043] The control system of the forklift transmission assembly based on the electromagnetic proportional valve has various connection and communication modes with the whole vehicle, which can be suitable for vehicles with different configurations and has strong versatility. In addition, the addition of the control module enables the whole vehicle to achieve a higher level of intelligent control, which greatly improves the informatization and intelligence of the whole vehicle.

[0044] The invention can calibrate the proportional valve pressure regulation curve and the inching pedal opening according to different working conditions and different usage scenarios, so that the whole vehicle can achieve efficient and comfortable operation under different working conditions and scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The figure is a schematic diagram of a control system of a forklift transmission assembly based on an electromagnetic proportional valve according to an embodiment of the present invention.

[0046] Figure 2 This is a logic roadmap for the reverse inching condition control of an embodiment of the present invention.

[0047] Figure 3 It is a control logic diagram of calibration and overshoot mode according to an embodiment of the present invention.

[0048] Figure 4 A diagram of a forklift hydraulic shift control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0050] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] See also Figures 1 to 3 As shown, the present invention provides a control system for a forklift transmission assembly based on an electromagnetic proportional valve, including: an inching-reverse gear lookup module 10, an inching-forward gear lookup module 20, an inching pedal angle lookup module 30, a first selection switch 41, a second selection switch 42, and a third selection switch 43.

[0052] In this embodiment, the gearbox oil pan temperature input interface 51 is connected to the input ports of the inching-reverse gear lookup module 10 and the inching-forward gear lookup module 20. The inching pedal input interface 52 is connected to the input end of the inching pedal angle lookup module 30, and the output end of the inching pedal angle lookup module 30 is respectively connected to the input ports of the inching-reverse gear lookup module 10 and the inching-forward gear lookup module 20. The reverse gear input interface 53 and the output end of the inching-reverse gear lookup module 10 are connected to the input end of the first selection switch 41. The forward gear input interface 54 and the output end of the inching-forward gear lookup module 20 are connected to the input end of the second selection switch 42. The output end of the second selection switch 42 is connected to the input end of the first selection switch 41; and the output end of the first selection switch 41 is connected to the input end of the third selection switch 43, and the output end of the third selection switch 43 outputs the electromagnetic proportional valve control current value.

[0053] In this embodiment, the first selection switch 41 has a "0" position and a "1" position, wherein the "0" position indicates that the vehicle is in the off-road mode, and the "1" position indicates that the vehicle is in the on-road mode, i.e., the reverse gear receives a signal to go on-road, and the vehicle does not receive a signal to go off-road. The second selection switch 42 has a "0" position and a "1" position, wherein the "0" position indicates that the vehicle is in the off-road mode, and the "1" position indicates that the vehicle is in the on-road mode, i.e., the forward gear receives a signal to go on-road, and the vehicle does not receive a signal to go off-road. And the third selection switch 43 has a "0" position and a "1" position, wherein the "0" position indicates that the vehicle is in the off-road mode, and the "1" position indicates that the vehicle is in the on-road mode, i.e., the vehicle receives a signal to go on-road, and the vehicle does not receive a signal to go off-road.

[0054] In one embodiment of the present invention, the inching pedal angle table lookup module 30 is associated with an angle and voltage curve table compiled according to the characteristics of the angle sensor, and outputs the pedal opening corresponding to the oil pressure.

[0055] In one embodiment of the present invention, the inching-reverse gear lookup module 10 includes a first first-order lookup module 11 and a first second-order lookup module 12. The output end of the inching pedal angle lookup module 30 is connected to the input end of the first first-order lookup module 11, the gearbox oil pan temperature input interface 51 and the output end of the first first-order lookup module 11 are connected to the input end of the first second-order lookup module 12, and the output end of the first second-order lookup module 12 is connected to the input end of the first selection switch 41. The first first-order lookup module 11 is associated with a curve corresponding to the inching pedal opening voltage and the hydraulic system oil pressure compiled based on the test, and the reverse gear position corresponding system oil pressure is output. The first second-order lookup module 12 is associated with a curve corresponding to the oil temperature, oil pressure and output current compiled based on the test and the characteristics of the electromagnetic proportional valve, and the reverse gear position corresponding electromagnetic proportional valve control current is output.

[0056] In one embodiment of the present invention, the inching-forward gear table lookup module 20 includes a second first-order table lookup module 21 and a second second-order table lookup module 22. The output end of the inching pedal angle table lookup module 30 is connected to the input end of the second first-order table lookup module 21. The transmission oil pan temperature input interface 51 and the output end of the second first-order table lookup module 21 are connected to the input end of the second second-order table lookup module 22, and the output end of the second second-order table lookup module 22 is connected to the input end of the second selection switch 42. The second first-order table lookup module 21 is associated with the inching pedal opening voltage and hydraulic system oil pressure corresponding curve compiled based on the test, and outputs the forward gear corresponding system oil pressure. The second second-order table lookup module 22 is associated with the oil temperature, oil pressure and output current corresponding curve compiled based on the test and the electromagnetic proportional valve characteristics, and outputs the electromagnetic proportional valve control current corresponding to the forward gear.

[0057] In one embodiment of the present invention, the control system of the forklift gearbox assembly further includes a calibration and overshoot mode current loop module 61 and a calibration and overshoot mode input module 62. Furthermore, the calibration and overshoot mode current loop module 61 and the calibration and overshoot mode input module 62 are connected to the input end of the third selection switch 43.

[0058] In one embodiment of the present invention, the control system of the forklift gearbox assembly further includes a current filter module 70 and an electromagnetic proportional valve current output interface 55. The input end of the current filter module 70 is connected to the output end of the third selection switch 43 to prevent current fluctuations from affecting the system. The current filtered by the current filter module 70 passes through the electromagnetic proportional valve current output interface 55 to control the opening of the electromagnetic proportional valve in the forklift hydraulic shift control system.

[0059] In one embodiment of the present invention, the control system of the forklift transmission assembly based on the electromagnetic proportional valve can be connected to the relevant system of the whole vehicle through a CAN line or a hard line, and the received gear signal is converted into a current signal of the electromagnetic proportional valve to realize gear control, and the received micro-motion pedal opening is converted into a current signal of the electromagnetic proportional valve to realize micro-motion control.

[0060] In one embodiment of the present invention, Figure 1 As shown in the figure, the control logic route of the forward inching condition is:

[0061] The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal. The voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module 30, and then the system oil pressure value corresponding to the forward gear under the corresponding inching pedal opening is found through the second first-order lookup module 21. The temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the second first-order lookup module 21, and finds the electromagnetic proportional valve control current value corresponding to the forward gear through the second second-order lookup module 22.

[0062] At this time, the forward gear signal corresponding to the second selection switch 42 is set to "1", the reverse gear signal corresponding to the first selection switch 41 is set to "0", and the calibration and overshoot mode corresponding to the third selection switch 43 are set to "0". The logic flow is judged by the second selection switch 42, the logic flow is judged by the first selection switch 41, and the logic flow is judged by the third selection switch 43. At this time, the logic runs as follows Figure 1 As shown, the solenoid valve working current corresponding to the forward gear output by the second second-order table lookup module 22 is input to the current filter module 70 through the second selection switch 42, the first selection switch 41, and the third selection switch 43, and is output to the solenoid proportional valve for execution through the solenoid proportional valve current output interface 55 after filtering. Figures 1 to 3 The middle dotted line,indicates the data flow.

[0063] In one embodiment of the present invention, Figure 2 As shown in the figure, the control logic route of the backward inching condition is:

[0064] The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal. The voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module 30, and then the system oil pressure value corresponding to the reverse gear position under the corresponding inching pedal opening is found through the first first-order lookup module 11. The temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the first first-order lookup module 11, and finds the electromagnetic proportional valve control current value corresponding to the reverse gear position through the first second-order lookup module 12.

[0065] At this time, the reverse gear signal corresponding to the first selection switch 41 is set to "1", the forward gear signal of the second selection switch 42 is set to "0", and the calibration and overshoot mode corresponding to the third selection switch 43 are set to "0". After the second selection switch 42 judges, the logic flow goes down, after the first selection switch 41 judges, the logic flow goes up, and after the third selection switch 43 judges, the logic flow goes down. At this time, the logic runs as follows Figure 2 As shown, the solenoid valve working current corresponding to the reverse gear output by the first second-order table lookup module 12 is input to the current filtering module 70 through the first selection switch 41 and the third selection switch 43, and after filtering, it is output to the solenoid proportional valve for execution through the solenoid proportional valve current output interface 55.

[0066] In one embodiment of the present invention, Figure 3As shown, the control logic route of the calibration and overshoot mode is: at this time, the calibration and overshoot mode is entered, the reverse gear signal corresponding to the first selection switch 41 is set to "0", and the forward gear signal corresponding to the second selection switch 42 is set to "0", and the calibration and overshoot mode input module 62 is set to "1". After judgment by the first selection switch 41, the logic flow goes down, after judgment by the second selection switch 42, the logic flow goes down, and after judgment by the third selection switch 43, the logic flow goes up.

[0067] The calibration and overshoot mode input module 62 outputs the calibration and overshoot current according to the current curve preset in the calibration and overshoot mode current loop module 61, and outputs it through the third selection switch 43. At this time, the solenoid proportional valve works according to the current curve preset in the calibration and overshoot mode current loop module 61.

[0068] At this point, the logic runs as follows Figure 3 As shown, the calibration and overshoot mode current loop module 61 outputs the calibration and overshoot current according to the preset current curve, and the third selection switch 43 inputs the current to the current filter module 70, which is output to the electromagnetic proportional valve for execution by the electromagnetic proportional valve current output interface 55 after filtering. At this time, the electromagnetic proportional valve works according to the preset current curve. This mode is mainly used to debug the gearbox and clutch functions and calibrate the clutch engagement point current during the test phase.

[0069] See also Figures 1 to 4 As shown, the present invention also provides a forklift hydraulic shift control system, which uses the control system of the forklift gearbox assembly based on the electromagnetic proportional valve as described above, including: an oil storage tank 1, a filter 2, an oil supply pump 3, an electromagnetic proportional valve 4, a forward gear clutch 5, a reverse gear clutch 6 and a main pressure regulating valve 7.

[0070] In this embodiment, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve is connected to the electromagnetic proportional valve 4 for communication. The oil in the oil storage tank 1 is filtered by the filter 2, and the transmission oil is pressurized by the oil supply pump 3 and then divided into two paths at the outlet, one entering the shift oil circuit and the other entering the acceleration oil circuit. The electromagnetic proportional valve 4, the forward gear clutch 5, and the reverse gear clutch 6 are on the shift oil circuit. After the main pressure regulating valve 7 adjusts the pressure, it is input into the oil inlet channel at the bottom of the electromagnetic proportional valve 4. The control system of the forklift gearbox assembly based on the electromagnetic proportional valve accurately controls the movement of the electromagnetic proportional valve 4 through the output current, thereby controlling the oil pressure of the forward gear clutch 5 and the reverse gear clutch 6, and realizing the functions of each gear and micro-motion.

[0071] In one embodiment of the present invention, in the neutral state, the electromagnetic proportional valve 4 does not work, the valve core of the electromagnetic proportional valve 4 is in the middle position, and both the forward gear and the reverse gear clutches have no oil pressure and are not engaged.

[0072] In one embodiment of the present invention, in the forward gear condition, the control system of the forklift transmission assembly based on the electromagnetic proportional valve receives the gear position signal, proportionally increases the electromagnetic coil current of the S1 end of the electromagnetic proportional valve 4, the valve core moves toward the S1 end, the main oil circuit is connected with the forward gear clutch cavity, the oil pressure is proportionally established, the forward gear clutch 5 is engaged, and the forward gear power transmission is realized.

[0073] If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S1 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the forward gear clutch cavity oil circuit, and the forward gear clutch cavity is depressurized to realize the inching function in the forward gear mode. If the inching pedal is released at this time, the forward gear is restored.

[0074] In one embodiment of the present invention, in the reverse gear situation, the control system of the forklift transmission assembly based on the electromagnetic proportional valve receives the gear signal, proportionally increases the electromagnetic coil current of the S2 end of the electromagnetic proportional valve 4, the valve core moves toward the S2 end, the main oil circuit is connected with the reverse gear clutch cavity, the oil pressure is proportionally established, the reverse gear clutch engages, and the reverse gear power transmission is realized.

[0075] If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S2 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the reverse gear clutch cavity oil circuit, and the reverse gear clutch cavity is depressurized to realize the inching function in the reverse gear mode. If the inching pedal is released at this time, the reverse gear is restored.

[0076] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0077] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A control system for a forklift gearbox assembly based on an electromagnetic proportional valve, characterized in that: include: An inching-reverse gear lookup module (10), an inching-forward gear lookup module (20), an inching pedal angle lookup module (30), a first selection switch (41), a second selection switch (42), and a third selection switch (43); The gearbox oil pan temperature input interface (51) is connected to the input ports of the inching-reverse gear table lookup module (10) and the inching-forward gear table lookup module (20); The inching pedal input interface (52) is connected to the input end of the inching pedal angle table lookup module (30), and the output end of the inching pedal angle table lookup module (30) is respectively connected to the input ports of the inching-reverse gear table lookup module (10) and the inching-forward gear table lookup module (20); The reverse gear input interface (53) and the output end of the inching-reverse gear look-up module (10) are connected to the input end of the first selection switch (41); The forward gear input interface (54) and the output end of the inching-forward gear table lookup module (20) are connected to the input end of the second selection switch (42); The output end of the second selection switch (42) is connected to the input end of the first selection switch (41); and the output end of the first selection switch (41) is connected to the input end of the third selection switch (43), and the output end of the third selection switch (43) outputs the electromagnetic proportional valve control current value.

2. The control system of the forklift gearbox assembly based on the electromagnetic proportional valve according to claim 1 is characterized in that: The micro-pedal angle lookup module (30) is associated with an angle and voltage curve table compiled according to the characteristics of the angle sensor, and outputs the pedal opening corresponding to the oil pressure.

3. The control system of the forklift gearbox assembly based on the electromagnetic proportional valve according to claim 2 is characterized in that: The inching-reverse gear table lookup module (10) comprises a first first-order table lookup module (11) and a first second-order table lookup module (12); The output end of the inching pedal angle table lookup module (30) is connected to the input end of the first first-order table lookup module (11); the gearbox oil pan temperature input interface (51) and the output end of the first first-order table lookup module (11) are connected to the input end of the first second-order table lookup module (12); and the output end of the first second-order table lookup module (12) is connected to the input end of the first selection switch (41); The first-order table lookup module (11) is associated with a curve corresponding to the inching pedal opening voltage and the hydraulic system oil pressure compiled according to the test, and outputs the system oil pressure corresponding to the reverse gear position; The first and second order table lookup modules (12) are associated with a curve corresponding to oil temperature, oil pressure and output current compiled based on experiments and electromagnetic proportional valve characteristics, and the output reverse gear position corresponds to the electromagnetic proportional valve control current.

4. The control system of the forklift gearbox assembly based on the electromagnetic proportional valve according to claim 2 is characterized in that: The inching-forward gear table lookup module (20) comprises a second first-order table lookup module (21) and a second second-order table lookup module (22); The output end of the inching pedal angle table lookup module (30) is connected to the input end of the second first-order table lookup module (21); the gearbox oil pan temperature input interface (51) and the output end of the second first-order table lookup module (21) are connected to the input end of the second second-order table lookup module (22); and the output end of the second second-order table lookup module (22) is connected to the input end of the second selection switch (42); The second first-order table lookup module (21) is associated with a curve corresponding to the inching pedal opening voltage and the hydraulic system oil pressure compiled according to the test, and outputs the system oil pressure corresponding to the forward gear position; The second second-order table lookup module (22) is associated with a curve corresponding to oil temperature, oil pressure and output current compiled based on experiments and electromagnetic proportional valve characteristics, and outputs a control current of the electromagnetic proportional valve corresponding to the forward gear position.

5. The control system of a forklift gearbox assembly based on an electromagnetic proportional valve according to claim 1, characterized in that: The control system of the forklift gearbox assembly further comprises a calibration and overshoot mode current loop module (61) and a calibration and overshoot mode input module (62); and the calibration and overshoot mode current loop module (61) and the calibration and overshoot mode input module (62) are connected to the input end of the third selection switch (43).

6. The control system of the forklift gearbox assembly based on the electromagnetic proportional valve according to claim 3 is characterized in that: The control logic of the backward inching condition is: The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal; the voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module (30), and then the system oil pressure value corresponding to the reverse gear position when the inching pedal opening is lowered is found through the first first-order lookup module (11); the temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the first first-order lookup module (11), and finds the electromagnetic proportional valve control current value corresponding to the reverse gear position through the first second-order lookup module (12); At this time, the reverse gear signal corresponding to the first selection switch (41) is set to "1", the forward gear signal of the second selection switch (42) is set to "0", and the calibration and overshoot modes corresponding to the third selection switch (43) are set to "0"; after the second selection switch (42) determines, the logic flow goes down, after the first selection switch (41) determines, the logic flow goes up, and after the third selection switch (43) determines, the logic flow goes down.

7. The control system of a forklift transmission assembly based on an electromagnetic proportional valve according to claim 4, characterized in that: The control logic of forward inching condition is: The angle sensor connected to the inching pedal converts the driver's demand into an electrical signal; the voltage value corresponding to the inching pedal opening is found through the inching pedal angle lookup module (30), and then the system oil pressure value corresponding to the forward gear position under the corresponding inching pedal opening is found through the second first-order lookup module (21); the temperature sensor collects the real-time oil pan temperature value and combines it with the system oil pressure value output by the second first-order lookup module (21), and finds the electromagnetic proportional valve control current value corresponding to the forward gear position through the second second-order lookup module (22); At this time, the forward gear signal corresponding to the second selection switch (42) is set to "1", the reverse gear signal corresponding to the first selection switch (41) is set to "0", and the calibration and overshoot modes corresponding to the third selection switch (43) are set to "0"; after the second selection switch (42) determines, the logic flow goes on the upper path, after the first selection switch (41) determines, the logic flow goes off the lower path, and after the third selection switch (43) determines, the logic flow goes off the lower path.

8. The control system of a forklift gearbox assembly based on an electromagnetic proportional valve according to claim 5, characterized in that: The control logic of calibration and overshoot mode is: At this time, the calibration and overshoot mode is entered, the reverse gear signal corresponding to the first selection switch (41) is set to "0", the forward gear signal corresponding to the second selection switch (42) is set to "0", the calibration and overshoot mode input module (62) is set to "1", the logic flow is judged by the first selection switch (41), the logic flow is judged by the second selection switch (42), and the logic flow is judged by the third selection switch (43). The calibration and overshoot mode input module (62) outputs the calibration and overshoot current according to the current curve preset in the calibration and overshoot mode current loop module (61), and outputs it through the third selection switch (43). At this time, the electromagnetic proportional valve works according to the current curve preset in the calibration and overshoot mode current loop module 61.

9. A forklift hydraulic shift control system, characterized in that: A control system for a forklift gearbox assembly based on an electromagnetic proportional valve according to any one of claims 1 to 8, comprising: an oil storage tank (1), a filter (2), an oil supply pump (3), an electromagnetic proportional valve (4), a forward gear clutch (5), a reverse gear clutch (6) and a main pressure regulating valve (7); Wherein, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve is communicatively connected with the electromagnetic proportional valve (4); The oil in the oil storage tank (1) is filtered by the filter (2), and the transmission oil is pressurized by the oil supply pump (3) and then divided into two paths at the outlet; after the pressure is adjusted by the main pressure regulating valve (7), it is input into the oil inlet channel at the bottom of the electromagnetic proportional valve (4); The control system of the forklift gearbox assembly based on the electromagnetic proportional valve accurately controls the movement of the electromagnetic proportional valve (4) through the output current, thereby controlling the oil pressure of the forward gear clutch (5) and the reverse gear clutch (6), thereby realizing the functions of each gear and micro-motion.

10. The forklift hydraulic shift control system according to claim 9, characterized in that: In the neutral state, the electromagnetic proportional valve (4) does not work, the valve core of the electromagnetic proportional valve (4) is in the middle position, and both the forward gear and the reverse gear clutches have no oil pressure and are not engaged; In the forward gear, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the gear position signal, proportionally increases the electromagnetic coil current of the electromagnetic proportional valve (4) at the S1 end, the valve core moves toward the S1 end, the main oil circuit is connected with the forward gear clutch cavity, the oil pressure is proportionally established, the forward gear clutch (5) is engaged, and the forward gear power transmission is realized; If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S1 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the forward gear clutch cavity oil circuit, and the forward gear clutch cavity is depressurized to realize the inching function in the forward gear mode. If the inching pedal is released at this time, the forward gear is restored; In the reverse gear, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the gear signal, increases the electromagnetic coil current of the electromagnetic proportional valve (4) at the S2 end in proportion, the valve core moves toward the S2 end, the main oil circuit is connected with the reverse gear clutch cavity, the oil pressure is built up in proportion, the reverse gear clutch is engaged, and the reverse gear power transmission is realized; If the inching pedal is pressed at this time, the control system of the forklift gearbox assembly based on the electromagnetic proportional valve receives the electrical signal converted from the inching pedal opening, releases the electromagnetic coil current at the S2 end proportionally, and the valve core moves to the middle position, reducing or cutting off the main oil circuit and the reverse gear clutch cavity oil circuit, and the reverse gear clutch cavity is depressurized to realize the inching function in the reverse gear mode. If the inching pedal is released at this time, the reverse gear is restored.

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