JPH0348370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a clutch control method in switchback running of a vehicle equipped with an automatic transmission.

(Prior Art) In recent years, various vehicles equipped with automatic transmissions have been proposed. Vehicles equipped with these automatic transmissions are required to be able to perform various types of driving similar to conventional manual transmission vehicles, including switchback driving.

(Problems to be Solved by the Invention) However, when a switchback operation is performed in a vehicle equipped with an automatic transmission, the control amount for the operation amount is uniquely determined.

Therefore, it is not possible to adjust the amount of control in switchback driving depending on various driving conditions such as the skill and preference of the driver or the conditions of the location where the vehicle is driven.

The purpose of this invention is to solve the above problems and to provide an automatic transmission that can select and execute switchback driving according to various driving conditions such as the skill and preference of the driver or the conditions of the place where the vehicle is driving. An object of the present invention is to provide a clutch control method for switchback driving of a vehicle.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned object, the present invention operates a forward/reverse control lever while the car is running, and moves from a direction point that corresponds to the direction of travel at the time to a direction in the opposite direction. In a driving method for a vehicle equipped with an automatic transmission that performs switchback driving by switching to a direction point in the driving direction, data for calculating negative acceleration relative to the depression angle of the accelerator pedal is provided for each different driving condition. Data is appropriately selected by the selection means, and based on the data selected by the selection means, the negative acceleration relative to the depression angle of the accelerator pedal at that time is compared with the actual negative acceleration at that time, and the actual negative acceleration is determined. The gist of this invention is to provide a clutch control method during switchback driving of a vehicle equipped with an automatic transmission, which controls the engagement state of the clutch so that the acceleration becomes a negative acceleration at the depression angle of the accelerator pedal.

(Function) The vehicle is decelerated when the gear of the automatic transmission is switched in the direction opposite to the direction of travel for switchback driving. At this time, the driver uses the selection means to select in advance one of the data for calculating the negative acceleration with respect to the depression angle of the accelerator pedal provided for each driving condition, and based on the selected data. A negative acceleration with respect to the depression angle of the accelerator pedal at that time is calculated. This calculated negative acceleration is then compared with the actual negative acceleration at that time. Based on the comparison, the vehicle is controlled to decelerate by adjusting the engagement state of the clutch so that the actual negative acceleration becomes a negative acceleration relative to the depression angle.

(Example) An example in which the present invention is embodied in a forklift will be described below with reference to the drawings.

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 drive wheels 5 are driven forward and backward through the differential gear mechanism 4 at a predetermined gear ratio. The engine 1 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 dry single plate clutch 2 that turns on and off the output of the engine 1 is connected to a clutch control actuator 6.
The connected state of the clutch 2 is adjusted relative to the stroke amount of the rod 6a, which expands and contracts based on the drive of the clutch 2. On the other hand, the automatic transmission 3 can be shifted between 1st speed (low speed) and 2nd speed (high speed) by driving the shift switching actuator 7, and can shift between forward travel and neutral speed by driving the forward/reverse switching actuator 8. (neutral) and reverse driving.

Next, an electric circuit for driving and controlling each of the actuators 6 to 8 will be explained with reference to FIG. 2.

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 12. The engine rotation speed sensor 13 detects the rotation speed of the output shaft of the engine 1, as shown in FIG. 1, and outputs the detection signal to the interface 12.

The stroke detection sensor 14 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 detected signal is converted into a digital signal by the A/D converter 15 and output to the interface 12.
The pedal operation amount detection sensor 16 is composed of a potentiometer, and is connected to the accelerator pedal 1 provided at the driver's seat.
7 is detected, and the detection signal is converted into a digital signal by the A/D converter 18 and output to the interface 12.

The forward/reverse movement detection sensor 19 detects the switching state (forward, neutral,
In other words, the direction point is detected and the detection signal is sent to the interface 12.
Output to.

Driving mode selection switch 21 as selection means
is a switch that is installed in the driver's seat and selects the deceleration level during switchback driving depending on the driving conditions.The selection operation of the selection switch 21 selects one of the three types of hard mode, normal mode, and soft mode described later. One switchback driving mode is selected and the selection signal is output to interface 12.

The microcomputer 31 includes a central processing unit (hereinafter referred to as CPU) 32, a program memory 33 consisting of a read-only memory (ROM) that stores control programs, and a readable and rewritable memory (ROM) that temporarily stores arithmetic processing results, etc. Consists of a working memory 34 consisting of RAM),
The CPU 32 operates based on program data stored in the program memory 33.

The CPU 32 receives signals from the sensors, switches, etc. through the interface 12. Then, the CPU 32 sequentially calculates the running speed Vx and acceleration Ax of the forklift at that time based on the detection signal from the vehicle speed sensor 11, and
The engine speed at that time is calculated based on the detection signal from the engine speed sensor 13, and the calculation result is stored in the working memory 34. Similarly, the CPU 32 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 14.
That is, in addition to calculating the connection state of the clutch 2, the depression angle x of the accelerator pedal 17 at that time is calculated based on the detection signal from the pedal operation amount detection sensor 16, and is stored in the working memory 34. .

Furthermore, the CPU 31 controls the forward and backward movement detection sensor 1.
The direction point of the forward/backward operating lever 20 at that time is determined based on the detection signal from the drive mode selection switch 21, and the switchback drive mode at that time is determined based on the selection signal from the drive mode selection switch 21. working memory 3
Store in 4.

Note that each calculation and judgment performed by the CPU 32 on these signals is performed based on program data stored in the program memory 33 in advance.

Further, the CPU 32 drives and controls the clutch control, shift switching, and forward/reverse switching actuators 6 to 8, respectively, via the interface 12 and the actuator drive circuits 35, 36, and 37 based on predetermined program data. I'm starting to do that. Further, the CPU 32 drives and controls the stepping motor 39 via the interface 12 and the motor drive circuit 38 based on predetermined program data. Same motor 3
Reference numeral 9 is drivingly connected to a throttle valve of the engine 1, and the opening degree of the throttle valve is controlled based on the amount of rotation of the motor 39.

When the CPU 32 determines that the forward/reverse operation lever 20 has been switched from a direction point corresponding to the direction of travel to a direction point in the opposite direction of travel during driving, the CPU 32 executes processing operations for switchback travel. ing.

The CPU 32 drives and controls the clutch control, shift switching, and forward/reverse switching actuators 6 to 8 in accordance with a predetermined program for switchback running.

Further, the CPU 32 selects the three types of driving modes shown in FIG. 3 selected by the driving mode selection switch 21 during switchback driving, which will be described later, and when the automatic transmission 3 is switched in the opposite direction to the driving direction. (Hard mode T1, normal mode T2, and soft mode T3), the negative acceleration An for the depression angle x of the accelerator pedal 17 at that time is determined in one driving mode, and the forklift is driven in that negative acceleration. acceleration
It has come to be controlled so that it becomes An.

This negative acceleration control is performed by the CPU 32 controlling the connection state of the dry single-plate clutch 2 (to be described later), that is, by controlling the amount of expansion and contraction of the rod 6a of the clutch control actuator 6.

Next, the operation of the electric block circuit constructed as described above will be explained according to the flowcharts shown in FIGS. 4 and 5.

Now, while the forklift is moving forward at a predetermined speed, the driver
When the vehicle is switched from forward to reverse, the CPU 32 determines that the direction point is switched from forward to reverse based on the detection signal from the forward/reverse detection sensor 19, and executes switchback control.

After disconnecting the dry single plate clutch 2, the CPU 32
The automatic transmission 3 is driven by controlling the forward/reverse switching actuator 8 via the actuator drive circuit 37.
Switch the gear from forward to reverse (step 1).

When the automatic transmission 3 changes gears from forward to reverse, the CPU 32 first determines the driving mode based on the selection operation of the driving mode selection switch 21 (step 2). When the hard mode T1 is selected by the selection switch 21, the hard mode driving control is activated, when the normal mode T2 is selected, the normal mode driving control is activated, and when the soft mode T3 is selected, the soft mode driving control is activated. is executed (steps 3, 4, 5).

If the normal mode T2 is selected in advance by the driver, the CPU 32 determines the depression angle of the accelerator pedal 17 according to the normal mode T2 among the hard mode T1, normal mode T2, and soft mode T3, as shown in FIG. Data for calculating the negative acceleration An with respect to x is selected from the program memory 33 (step 6).
Next, CPU32 uses accelerator pedal 1 at that time.
Pedal operation amount detection sensor 1 detects the depression angle x of 7.
6 (step 7).

As shown in FIG. 3, the CPU 32 calculates the calculated negative acceleration for the depression angle x based on the data for calculating the negative acceleration for the depression angle x in the selected normal mode T2.
Calculate An (step 8).

On the other hand, the CPU 32 performs differential processing on the detection signal from the vehicle speed detection sensor 11 to calculate the negative acceleration Ax of the forklift at that time (step 9 to
11). Then, CPU32 calculates this actual negative acceleration
The clutch control actuator 6 is operated to control the connection state of the dry single plate clutch 2 so that Ax becomes the negative acceleration An obtained above (step
12). In other words, the CPU 32 receives the actual negative acceleration
When Ax is larger than the negative acceleration An obtained by calculation, in the direction of disengaging clutch 2 (step 15),
On the other hand, when the actual negative acceleration Ax is smaller than the calculated negative acceleration An, the half-clutch connection state is controlled in the direction of connecting clutch 2 so that the calculated negative acceleration An is reached. Step 13).

Further, when the actual negative acceleration Ax matches the calculated negative acceleration An, the CPU 32 controls the connection state of the clutch 2 to maintain the half-clutch state at that time (step 14).

Therefore, for deceleration at this time, the negative acceleration An can be changed as appropriate depending on the depression angle x of the accelerator pedal 17.

And the forklift has this negative acceleration An
Accordingly, the vehicle decelerates, reverses direction, moves backward, and completes switchback travel.

In this embodiment, switchback driving from forward to reverse has been described, but switchback from reverse to forward is also performed by the same processing operation.

In this way, in this embodiment, the negative acceleration An can be changed as appropriate depending on the depression angle x of the accelerator pedal 17, so the reversal speed of switchback driving can be increased according to the driver's preference. Moreover, based on the selection of the driving mode selection switch 21, one of the hard mode T1, normal mode T2, and soft mode T3 can be selected, so that the desired switchback can be selected depending on the driving conditions such as the skill of the driver and the work place. Can run. That is, as shown in FIG. 3, in the hard mode T1, the negative acceleration An with respect to the depression angle x is larger as a whole than in the normal mode T2 and the soft mode T3, so the sensitivity of the accelerator pedal 17 depending on the depression angle x is It is better than the mode of
It is suitable for places where the work place is narrow, and on the contrary, in the case of soft mode T3, the negative acceleration An with respect to the depression angle It can decelerate and is suitable for cargo handling work that is likely to cause weight imbalance, or when a driver with low skill is driving because there is no sudden deceleration even if there is a mistake in pedal operation.

Further, although the above embodiment is applied to a forklift, it goes without saying that the invention may be applied to other vehicles without departing from the spirit of the invention.

Effects of the Invention As detailed above, according to the present invention, it is possible to select and execute switch-back driving according to various driving conditions such as the skill and preference of the driver, or differences in the driving location of the vehicle. This is an industrially excellent invention as a clutch control method for switchback driving of a vehicle equipped with a transmission.

[Brief explanation of drawings]

Fig. 1 is a mechanical diagram showing the mechanism of the drive system of a forklift embodying this invention, Fig. 2 is an electric block circuit diagram of the forklift, and Fig. 3 shows the negative effects of the accelerator pedal depression angle in each driving mode. 4 and 5 are flowcharts for explaining the action of this forklift. 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, 7 is a shift switching actuator, 8 is a forward/reverse switching actuator, 11 is a vehicle speed sensor,
14 is a stroke detection sensor, 16 is a pedal operation amount detection sensor, 17 is an accelerator pedal, 19 is a forward/reverse motion detection sensor, 20 is a forward/reverse motion control lever, 21
31 is a running mode selection switch, 31 is a microcomputer, 32 is a central processing unit (CPU), 33 is a program memory, and 34 is a working memory.

Claims (1)

[Claims] 1. While the vehicle is running, operate the forward/reverse control lever to switch from a direction point that corresponds to the current direction of travel to a direction point in the opposite direction of travel to perform switchback travel. In a driving method for a vehicle equipped with an automatic transmission, data for calculating negative acceleration with respect to the depression angle of an accelerator pedal is provided for each different driving condition, and the data is appropriately selected by a selection means, and the data is appropriately selected by the selection means. Compare the negative acceleration with respect to the depression angle of the accelerator pedal at that time and the actual negative acceleration at that time based on the selected data, so that the actual negative acceleration becomes the negative acceleration at the depression angle of the accelerator pedal. , a clutch control method in switchback driving of a vehicle equipped with an automatic transmission which controls the engagement state of the clutch.