JPH0569016B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission control device for an industrial vehicle such as a forklift with an automatic transmission.

(Prior Art) In a forklift with an automatic transmission, a clutch drive means switches between a low speed side and a high speed side shift with the clutch disengaged, and after the shift is completed, the clutch is connected again. Conventionally, when switching from a low-speed shift to a high-speed shift, when the clutch drive means disengages the clutch, the throttle drive means closes the throttle regardless of the amount of depression of the accelerator pedal, and then gradually releases the throttle again. When the clutch was fully engaged, the throttle was opened to the opening corresponding to the accelerator pedal.

(Problems to be Solved by the Invention) For this reason, in the past, when the clutch was connected after the shift was completed, the engine speed increased, sometimes causing a shock.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and provides an automatic shift system that can prevent shift shocks as much as possible by reducing shift shocks when switching from a low speed shift to a high speed shift. The purpose of this invention is to provide a control device.

(Means for Solving the Problems) The present invention provides a shift changer for switching and connecting gears of a high-speed side shift or a low-speed side shift in an industrial vehicle equipped with a throttle drive means that drives a throttle based on the operation of a throttle operation means. a drive means; a clutch drive means for driving a clutch provided between the engine output and the automatic transmission to move toward and away from the automatic transmission when changing gears from the high-speed side shift to the low-speed side shift; When a gear is changed, a switching determination means determines whether the gear has been changed; a clutch connection determination means which calculates a clutch connection state by the clutch drive means; When the determining means determines that the clutch is in the disengaged state, it outputs a first control signal to the throttle driving means based on the results of both determinations, and closes the throttle regardless of the operation of the throttle operating means. A first method for reducing the throttle in proportion to the amount of operation of the throttle operation means according to the calculated value by the clutch connection determination means until the clutch connection determination means determines that the clutch is in a fully engaged state again.
When the clutch connection determining means determines that the clutch is fully engaged, a second control signal is output to the throttle driving means based on the determination result, and the throttle is opened until the clutch is fully engaged. The gist of the present invention is to include a throttle control means for opening the throttle from the first target opening degree to a second target opening degree corresponding to the operation amount of the throttle operation means after a predetermined period of time after the throttle operation means has touched the throttle.

(Operation) With the above configuration, when the gear is changed from the low speed side shift to the high speed side shift, the switching determination means determines the switching state. Further, a clutch connection determining means determines the disengaged state of the clutch. Then, based on the results of both determinations, the throttle control means outputs a first control signal to the throttle drive means. In response to this first control signal, the throttle driving means closes the throttle regardless of the operation of the throttle operating means, and then gradually adjusts the throttle to the operating amount of the throttle operating means until the clutch is fully engaged again. The opening is made to a first target opening degree which is smaller than the corresponding second target opening degree. When the clutch engagement determining means determines whether the clutch is fully engaged, the throttle controlling means outputs a second control signal to the throttle driving means based on the determination result. Then,
In response to this second control signal, the throttle drive means opens the throttle to the second target opening a predetermined time after the clutch is completely engaged. Therefore, in the present invention, the first stage is from when the clutch is disengaged due to gear switching until the clutch is fully engaged, and the second stage is from when the clutch is fully engaged until after a predetermined period of time has elapsed. Throttle drive control is performed in two stages.

(Embodiment) Next, a preferred embodiment in which the present invention is embodied in a forklift will be described below with reference to FIGS. 1 to 6.

Figure 1 shows the mechanism of the drive system of a forklift.The output of an engine 1 is transmitted to an automatic transmission 3 via a dry single-plate clutch 2.
The driving wheels 5 are driven forward and backward by a predetermined transmission via the differential gear 4. Also, engine 1
It is also used as a drive source for a hydraulic pump that supplies hydraulic oil to a lift cylinder for raising and lowering the fork and a tilt cylinder for tilting the mast.

The connection state of the dry single-plate clutch 2 that turns on and off the output of the engine 1 is adjusted in relation to the stroke amount of a rod 6a that expands and contracts based on the drive of a clutch control actuator 6 as a clutch driving means. . On the other hand, the automatic transmission 3 can be shifted to 1st speed (low speed) or 2nd speed (high speed) by driving a shift switching actuator 7 as a shift switching driving means, and drives a forward/forward switching actuator 8. It is possible to switch between forward travel, neutral (neutral), and reverse travel. The vehicle speed sensor 11 detects the rotational speed of the output shaft of the automatic transmission 3, as shown in FIG. 1, and outputs the detection signal to the input/output interface 14.

Next, an electric circuit for driving and controlling each of the actuators 6 to 8 will be explained with reference to FIG.

The stroke detection sensor 15 is composed of a potentiometer, and is connected to the clutch control actuator 6.
The stroke amount of the rod 6a is detected, and the detection signal is converted into a digital signal by the A/D converter 16 and output to the interface 14. The pedal operation amount detection sensor 17 is composed of a potentiometer, and detects the depression angle of an accelerator pedal 18, which is a throttle operation means provided at the driver's seat.
The detection signal is converted into a digital signal by an A/D converter 19 and output to the interface 14.

The forward/reverse movement detection sensor 20 detects the switching state (forward, neutral, reverse) of the forward/reverse movement operating lever 21 similarly provided at the driver's seat, that is, the direction point, and outputs the detection signal to the interface 14. The shift state detector 22 is provided in the shift switching actuator 7, and detects whether the shift switching actuator 7 is being driven to the 1st speed side.
It is detected whether the motor is being driven to the second speed side, and a detection signal thereof is output to the interface 14.

The microcomputer 25 is a switching determination means,
Central processing unit (hereinafter referred to as CPU) 2 as clutch connection determination means and throttle control means
6. Consisting of a program memory 27 consisting of a read-only memory (ROM) that stores control programs, and a working memory 28 consisting of a readable and rewritable memory (RAM) that temporarily stores arithmetic processing results, the CPU 26 uses the program memory It operates based on program data stored in 27.

The CPU 26 inputs detection signals from the respective sensors etc. through the interface 14. and,
The CPU 26 determines the accelerator pedal operation amount based on the detection signal from the pedal operation amount detection sensor 17, calculates the traveling speed of the forklift based on the detection signal from the vehicle speed sensor 11, and uses the calculation result for the work. It is stored in the memory 28. Then, the CPU 26 controls the opening degree of the engine throttle based on the determined accelerator pedal operation amount and controls the engine rotation speed. Note that the throttle opening degree corresponding to the operation amount of the accelerator pedal 18 is set in advance, and the data is stored in the program memory 27.

Further, the CPU 26 determines the stroke amount of the rod 6a of the clutch control actuator 6 at that time based on the detection signal from the stroke detection sensor 15.
That is, the connected state of the clutch 2 is calculated, and the direction point of the forward/reverse operation lever 21 at that time is determined based on the forward/reverse motion detection sensor 20.

Note that each calculation and judgment performed by the CPU 26 on these detection signals is performed based on data stored in the program memory 27 in advance.

Further, the CPU 26 drives and controls the clutch control, shift switching, and forward/reverse switching actuators 6 to 8 via the interface 14 and the actuator drive circuits 30, 31, and 32, respectively, based on predetermined program data. I'm starting to do that. Further, the CPU 26 drives and controls a stepping motor 34 as a throttle drive means via the interface 14 and the motor drive circuit 33 based on predetermined program data. The motor 34 is drivingly connected to the throttle valve of the engine 1.
The throttle opening degree is controlled based on the amount of rotation.

The program memory 27 stores not only control programs but also shift data for driving.
The shift data for driving is shift data for switching the automatic transmission 3 to the optimum shift state based on the amount of depression of the accelerator pedal 18, that is, the amount of accelerator opening and the traveling speed of the forklift. Based on this, switching control is performed to the gear corresponding to 1st or 2nd speed.

The program memory 27 also stores first throttle control data that is read out when shifting from 1st speed to 2nd speed, and the first throttle control data is stored when clutch 2 is activated as shown in FIG. Data for outputting a first control signal to the motor drive circuit 33 in order to open the throttle to a predetermined opening degree corresponding to the clutch stroke from when the clutch is disengaged to when the clutch is fully engaged, and the clutch stroke at each time. When the clutch stroke is fully engaged, the throttle opening is set as the first target opening at 80% of the opening corresponding to the accelerator pedal. Further, second throttle control data is stored in the program memory 27, and the second throttle control data is used to control the throttle 2 during a predetermined time period t after the clutch 2 is fully engaged, as shown in FIG. data for outputting a second control signal to the motor drive circuit 33 in order to open the throttle valve to a predetermined opening degree. The opening degree is set to correspond to the accelerator pedal. Readable and rewritable memory (hereinafter referred to as RAM)
28 is designed to temporarily store various calculation results of the CPU 26.

Next, the operation of the forklift constructed as described above will be explained according to the flowchart shown in FIG.

When the forklift is running in 1st gear and the accelerator pedal 18 is depressed, the CPU 2
6 calculates the current accelerator opening amount based on the detection signal from the pedal operation amount detection sensor 17, and calculates the current traveling speed based on the detection signal from the vehicle speed sensor 11, and runs based on both calculated values. Refer to the shift data for.

Then, the CPU 26 determines whether the current running state is the 2nd speed region or the 1st speed region.
Furthermore, based on the detection signal from the shift state detector 22, it is determined whether the current shift position of the shift switching actuator 7 is 1st gear or 2nd gear, and the determined result is combined with the shift data. It is determined whether or not the results determined based on the above match.

If they match, the CPU 26 continues running without shifting.
On the other hand, if it is determined that they do not match, the CPU 26
It is determined that this is a high-speed shift change (step 1, hereinafter the step will be referred to as S), and a shift process is performed. That is, the CPU 26 outputs a drive signal to the actuator drive circuit 30 to switch to a shift based on the shift data, and drives the clutch control actuator 6 to disengage the clutch 2 (time T0 shown in FIG. 4). Next, a drive signal is output to the actuator drive circuit 31 to drive and control the shift switching actuator 7, and the gears are brought into a predetermined connection state and set to a shift state (2nd speed) based on the read shift data, and then the actuator is driven. A drive signal is output to the circuit 30, and the clutch control actuator 6 is driven to connect the clutch 2 (at T2 shown in FIG. 4). That is, the clutch is displaced along line B shown in FIG.

Also, when the clutch 2 is disengaged (T 0 o'clock),
The CPU 26 outputs a control signal to the motor drive circuit 33 to drive the stepping motor 34 and close the throttle. Then, when the CPU 26 closes the throttle to the lowest position (time T1 shown in FIG. 4), it reads the first throttle control data and adjusts the clutch stroke based on the detection signal inputted from the stroke detection sensor 15 from time to time. is calculated, a control signal corresponding to the calculated clutch stroke is determined using the first throttle control data, and the determined control signal is output to the motor drive circuit 33. As a result, the throttle has an opening corresponding to the clutch stroke (S2). That is, the throttle opening changes along the curve shown by line A in FIG.

Further, the CPU 26 determines whether or not the clutch 2 is fully engaged based on the detection signal inputted from the stroke detection sensor 15 from time to time (S3), and continues the control in S2 until the clutch 2 is fully engaged. When clutch 2 is fully engaged (at T2) based on the control in S2, the throttle opening is 80% of the opening corresponding to the accelerator pedal, which is the first target opening. Become. Also, at this time, the CPU 26 determines in S3 that the clutch 2 is completely engaged, and then the CPU 26 reads the second throttle control data.

Then, the CPU 26 starts timing from when the clutch 2 is fully engaged based on a built-in timer, and uses the second throttle control data to determine a control signal corresponding to the measured time.
The determined control signal is output to the motor drive circuit 33. As a result, the throttle will have an opening corresponding to the measured time (S4). Then, the motor drive circuit 33 sends a control signal to open the throttle to an opening corresponding to the accelerator pedal when time t has elapsed since the clutch 2 was fully engaged.
By outputting the second target opening, the throttle opening corresponding to the accelerator pedal, which is the second target opening, can be obtained.

In this way, in the past, when the clutch was fully engaged, the throttle was opened to the opening corresponding to the accelerator pedal, as shown by the two-dot chain line in Fig. 4, which could cause a shock during gear shifting, but this invention completely solves the problem. This does not happen because the throttle is not opened sufficiently at the time of contact.

Note that the present invention is not limited to the above-mentioned embodiments, and can be arbitrarily modified without departing from the spirit of the present invention.

(Effects of the Invention) As described in detail above, when changing from a low-speed shift to a high-speed shift, the present invention first performs the following steps: , the throttle is opened only up to a first target opening degree which is reduced in proportion to the amount of operation of the throttle operating means, and the throttle is opened in a second stage until after a predetermined period of time has elapsed after the clutch is fully engaged. Since two-stage control is performed in which the gear is opened to the second target opening degree corresponding to the operation amount, it has an excellent effect of reducing the number of shift shocks and preventing shocks as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a mechanical diagram showing the drive system mechanism of a forklift according to an embodiment of the present invention, and FIG. 2 is an electric block circuit diagram of the same forklift.
Figure 3 is a flowchart for explaining the processing operation of the central processing unit (CPU), Figure 4 is an explanatory diagram showing clutch displacement and throttle opening displacement, and Figure 5 is a flowchart for explaining the processing operation of the central processing unit (CPU). FIG. 6 is an explanatory diagram showing the correspondence between the clutch stroke and the throttle opening. FIG. 6 is an explanatory diagram showing the correspondence between the elapsed time after the clutch is completely engaged and the throttle opening based on the second throttle control data. In the diagram, 1 is the engine, 2 is the dry single plate clutch,
3 is an automatic transmission, 6 is a clutch control actuator (clutch drive means), 7 is a shift changeover actuator (shift changeover drive means), 15 is a stroke detection sensor, 18 is an accelerator pedal (throttle operation means), and 22 is a gear shifter. status detector, 2
5 is a microcomputer, 26 is a central processing unit (switching determination means, clutch connection determination means, throttle control means), 27 is a program memory, 3
0 to 31 are actuator drive circuits, and 34 is a stepping motor.

Claims (1)

[Scope of Claims] 1. In an industrial vehicle equipped with a throttle drive means that drives the throttle based on the operation of the throttle operation means, there is provided a shift switching drive means for switching gears for a high-speed shift or a low-speed shift; A clutch driving means for driving a clutch provided between the engine output and the automatic transmission toward and away from the clutch when the gear is shifted or shifted to the low speed side; and when the gear is changed from the low speed side shift to the high speed side shift; a switching determining means for determining the switching; a clutch connection determining means for calculating the engagement state of the clutch by the clutch driving means; When it is determined that the clutch is in the fully engaged state, a first control signal is output to the throttle driving means based on the results of both determinations, and the throttle is closed regardless of the operation of the throttle operating means, and then the clutch is again in the fully engaged state. The throttle is opened to a first target opening degree which is decreased in proportion to the operation amount of the throttle operation means in accordance with the calculated value by the clutch connection determination means until the clutch connection determination means determines that When the clutch connection determining means determines that the clutch is fully engaged, it outputs a second control signal to the throttle driving means based on the determination result, and the throttle is activated after a predetermined period of time after the clutch is fully engaged. 1. An automatic transmission control device for an industrial vehicle, comprising a throttle control means for opening the throttle from a first target opening degree to a second target opening degree corresponding to the operation amount of the throttle operation means.