JPS6239333A - Running condition detecting method for vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To improve operational performance, by making the following running a driver is going to drive to be detected depending on whether the next forward or backward lever shifting is set or not in a preset specific time when the forward/backward shift gear is converted to the neutral position in a running. CONSTITUTION:An automatic transmission 3 connected to the engine 1 of a fork lift through a clutch 2 is shifted to the low and the high stages by a shift converting actuator 7, and to the forward, backward, and the neutral stages through a forward/backward shift converting actuator 8. In this case, when the forward/backward shift lever is converted to the neutral stage, it is detected whether the direction point (converting position) depending on the lever shifting is the same or not in a specific time, as well as the clutch 2 is disconnected. And the automatic transmission 3 and the clutch 2 are controlled to convert for a switchback running, when the shift lever is converted to a different converting position from the position just the lever is converted to the neutral position.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for determining whether a vehicle is running, and more particularly to a method for determining whether a vehicle is running with an automatic transmission.

(Prior Art) Conventionally, in a vehicle equipped with an automatic transmission, for example, a forklift equipped with an automatic transmission with a dry single-plate clutch, each time the direction point of the forward/reverse operation lever is changed, that is, the direction point of the plane reverse operation lever is changed. Each time the state is changed to forward, neutral, or reverse, the clutch and automatic transmission are immediately switched to correspond to the direction point of the forward/reverse operating lever.

(Problem to be Solved by the Invention) However, there is no problem when coasting with the forward/reverse control lever set to neutral while driving, but for example, if the forward/reverse control lever is set from forward to neutral while driving forward. When switching the direction point to reverse to perform switchback driving, the clutch and automatic transmission first perform a switching operation based on a neutral operation, and then perform a switching operation based on the reverse operation.

Therefore, despite the driver's intention to immediately perform switchback driving, one extra clutch and automatic transmission switching operation is required, and the clutch switching drive means and automatic transmission shift switching drive means for this purpose are wasted. There was a problem with the operation.

Further, a similar problem occurs when the driver changes the forward/reverse operation lever from forward to neutral during forward driving, but then changes his/her mind and returns it to forward again (referred to as coasting shift driving).

In order to solve the above-mentioned problems, the present invention eliminates unnecessary operations of the clutch switching drive means and the shift switching drive means of an automatic transmission by accurately determining the driver's intention to operate the forward/reverse operation lever. It is an object of the present invention to provide a method for determining whether a vehicle equipped with an automatic transmission is running, which can improve operability, reduce the burden on these drive means, and improve durability.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a system in which, when the forward/reverse operation lever is operated and the direction point "" is switched to neutral, the clutch is disengaged and the clutch is disengaged.
The difference in direction points based on the operation of the forward/reverse operation lever is detected for a predetermined period of time without switching the automatic transmission. Then, when the forward/reverse operation lever is switched to a direction point different from the direction point before switching to the neutral position, the automatic transmission and clutch are controlled to switch back. Furthermore, when the forward/reverse operation lever returns to the direction point before switching to the 21 Utral position, switching control of the automatic transmission and clutch for coasting shift driving is performed. In addition, when there is no difference in direction points based on the operation of a forward/reverse operation lever for a predetermined period of time, an automatic transmission is configured to perform switching control of the automatic transmission and clutch for coasting. The gist of this paper is a method for determining whether a vehicle is running.

(Function) When the forward/reverse operation lever is switched to neutral, the automatic transmission and clutch are not immediately shifted to the neutral mode, but a shift operation other than neutral is performed at a predetermined time from the switching point. Detect whether.

As a result, it is possible to accurately and reliably determine the driver's intention to operate the forward/reverse operating lever, and it is possible to rationally control switching of the automatic transmission and clutch based on the determination result.

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

Figure 1 shows the mechanism of the drive system of a forklift, in which the output of the engine 1 is transmitted through a dry single-plate clutch 2 to an automatic transmission 3.
The automatic transmission 3 drives the running drive wheels 5 forward and backward at a predetermined gear ratio via the differential gear mechanism 4. 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 connection state of the dry single-plate clutch 2 that turns on and off the output of the engine 1 is adjusted relative to the stroke amount of a rod 6a that expands and contracts based on the drive of the clutch control actuator 6. On the other hand, the automatic transmission 3 can shift between 1 (fast, low speed) and 2 (fast, high speed) by driving the shift switching actuator 7, and can shift between forward travel and neutral (neutral) by driving the forward/reverse switching actuator 8. ) and reverse travel.

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

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 detects the stroke of the rod 6a of the clutch control actuator 6, and the detection signal is sent to the A/D converter 1.
5, the signal is converted into a digital signal and output to the interface 12.

The pedal operation amount detection sensor 16 is composed of a potentiometer and detects the depression angle ex of the accelerator pedal 17 provided at the driver's seat, and the detection signal is converted into a digital signal by the A/D converter 18 and sent to the interface 12. Output.

The forward/backward movement detection sensor 19 detects the switching state (forward, neutral, reverse) of the forward/backward movement operating lever 20, which is also provided on the driver's seat.
That is, it detects the direction point and outputs the detection signal to the interface 12. The load detection sensor 21 consists of a pressure sensor, and is connected to the lift cylinder 2.
Detects the hydraulic pressure of the hydraulic oil in 2, 1, that is, fork 23
The weight of the cargo 24 on the A/
The signal is converted into a digital signal by the D converter 25 and output to the interface 12.

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

The CPU 32 receives detection 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 also calculates the running speed VX and acceleration Ax of the forklift at that time.
The engine rotation speed at that time is calculated based on the detection signal from 3, and the calculation result is stored in the working memory 34.

Similarly, the CPtJ32 calculates the stroke base of the rod 6a of the clutch control actuator 6 at that time based on the detection signal from the stall detection sensor 14, that is, the connection state of the clutch 2, and also calculates the connection state of the clutch 2 using the pedal operation amount detection sensor. Based on the detection signal from the accelerator pedal 16, the depression angle ex of the accelerator pedal 17 at that time is calculated and stored in the working memory 34.

Furthermore, the CPU 31 determines the current direction point of the forward/reverse operation lever 20 based on the detection signal from the forward/reverse motion detection sensor 19, and the current load G based on the detection signal from the load detection sensor 21.
X, that is, the weight of the cargo is calculated, and the calculation result is stored in the working memory 34.

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

The CPLJ 32 also controls the interface 12 and each actuator drive circuit 35 . based on predetermined program data. , 36 and 37, the clutch control, shift switching, and forward/reverse switching actuators 6 to 8 are driven and controlled, respectively. Furthermore, C
The PU 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 39
is drivingly connected to the throttle valve of the engine 1, and controls the opening degree of the throttle valve based on the amount of rotation of the motor 39.

When the CPU 32 determines that the forward/reverse operating lever 20 has been switched to neutral during driving, the CPU 32 performs a running determination processing operation, that is, the forward/reverse operating lever 20 operated by the driver.
2) A processing operation is executed to determine whether the Utral operation is an operation for performing switchback driving, coasting shift driving, or coasting driving.

Based on the determination result, the CPU 32 operates the clutch control, shift switching, and forward/reverse switching actuators 6 according to a predetermined program for switchback driving, coasting shift driving, or driving for coasting. -8 are drive-controlled.

In addition, when the CPLI 32 is running in a switchback mode (to be described later) and the automatic transmission 3 is switched in the opposite direction to the running direction, the CPLI 32 calculates the load GX,'?, as shown in FIG.
1' That is, the negative acceleration An with respect to the depression angle θX of the accelerator pedal 17 at that time is determined in advance according to the weight of the cargo 240, and the forklift is controlled to the negative acceleration An.

Note that the negative acceleration Δn with respect to the depression angle ex is calculated based on data stored in the program memory 33 in advance.

This negative acceleration control is performed by the CPU 32 controlling the connection state of the dry single-plate clutch 2 (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 electrical block circuit configured as described above will be explained according to the flowcharts shown in FIGS. 4 to 6.

Now, when the driver switches the forward/reverse operation lever 20 from forward to neutral while the forklift is traveling forward at a predetermined traveling speed, the CPIj 32 changes the direction point to neutral based on the detection signal from the forward/reverse motion detection sensor 19. In step 1), the clutch control actuator 6 is controlled via the interface 12 and the actuator drive circuit 35 to disengage the dry single-plate clutch 2 at the maximum speed (step 2). At the same time, The CPtJ32 activates a timer built into the CPU 32 to determine whether the forward/reverse operating lever 20 has been switched to a direction point other than neutral during a predetermined time (hereinafter referred to as set time t, 1 second in this embodiment). (Steps 3 and 4).

C, even if the set time t has elapsed, the reverse operation lever 20
When is not operated and the direction point changes, the CPU 32 executes a coasting control processing operation to cause the forklift to coast (step 5). That is, the CPtJ32 determines that coasting is occurring in response to the time-up, drives and controls the forward/reverse switching actuator 8, switches the gear of the automatic transmission Ia3 from forward to neutral, and then switches the disconnected dry single-plate clutch 2. Connecting. Therefore, the forklift will coast in this state.

On the other hand, when the operating lever 20 is switched to forward again within the set time, the CPU 32 determines that it is a coasting shift (step 6), and executes coasting shift control processing operation to make the forklift move forward again (step 7).
). The CPU 32 simply connects the dry single plate clutch 2 in response to the direction point being switched to forward again.

Therefore, the forklift will continue moving forward again.

Further, when the operating lever 20 is switched to reverse within the set time, the CPU 32 determines that a switchback is occurring (step 6), and executes a switchback control processing operation to cause the forklift to travel in a switchback mode (step 6).
Step 8).

In response to the direction point being switched from neutral to reverse, the CPU 32 drives and controls the stepping motor 39 to completely close the throttle valve (
Step 9). At the same time, the CPU 32 operates the clutch control actuator 6 to connect the dry single plate clutch 2 so that the speed Vx of the forklift is adjusted to the first reference speed V1 (in this embodiment, automatic The engine brake is applied to decelerate the forklift until the speed at which the transmission 3 can be switched from 2nd speed to 1st speed is reached (step 10.11>. At this time, the CPU 32 uses the detection signal from the vehicle speed sensor 11 to decelerate the forklift. It is determined by successive comparison whether the speed has been decelerated to the first reference speed v1 based on the calculated speed X at that time.

When the speed VX becomes lower than the first reference speed v1, the CPU 3
Step 2 determines whether the automatic transmission is in second gear or first gear (step 12). And the automatic transmission is 1
When the CPU 32 is in the speed state, the CPU 32 changes the speed VX to be described later.
The process moves on to a judgment as to whether or not the vehicle has been decelerated below the second reference speed V2 (in this embodiment, the speed at which the automatic transmission 3 can be switched from forward to reverse) stored in advance in the program memory 33 (step 17).

On the other hand, when the automatic transmission 3 is in 2nd speed, the CPU 32 drives and controls the clutch control actuator 6 to once disengage the dry single disc clutch 2 (step 13), and then drives the shift switching actuator 7 via the actuator drive circuit 36.
The gear of the automatic transmission 3 is changed from 2nd speed to 1st speed by controlling the drive of the automatic transmission 3 (step 14). Then, when the automatic transmission 3 switches to 1st speed, the CPU 32 again drives and controls the clutch control actuator 6 to connect the dry single plate clutch 2 (step 15), so that the forklift speed VX is set in advance. The engine brake is applied to decelerate the forklift until it reaches the second reference speed ■2 (step 16.17>).

When the speed VX becomes less than the second reference speed ■2, the CPU3
2 disengages the dry single-plate clutch 2 in the same manner as described above (step 18), and then drives and controls the forward/reverse switching actuator 8 via the actuator drive circuit 37 to operate the automatic transmission 3.
Change gear from forward to reverse (one step). At the same time, the CPLI 32 controls the stepping motor 39 to control the throttle valve, which has been completely closed, to an opening relative to the depression angle ex of the accelerator pedal 17, and also controls the stepping motor 39 to reverse the direction of travel. (Step 20).

When the automatic transmission Ifi 3 changes gears from forward to reverse (step 19), the CPLJ 32 detects the depression angle ex of the accelerator pedal 17 at that time in order to cause the forklift to further decelerate and stop and then immediately move backward. The sensor 16 calculates the current load G based on the detection signal from the load detection sensor 21.
Calculate X (steps 21 and 22).

The CPU 32 selects data from the program memory 33 for calculating the negative acceleration An for the depression angle θX shown in FIG. 3 under the load Gx at that time. Then, when the data for calculating the negative acceleration with respect to the depression angle θX is selected, the CPU 32 calculates the negative acceleration An with respect to the computed depression angle θX based on the selected data (step 23).

On the other hand, the CPU 32 differentiates the detection signal from the vehicle speed detection sensor 11 and outputs the negative acceleration AX of the forklift at that time (steps 24 to 26). Then, the clutch control actuator 6 is operated to control the connection state of the dry single disc clutch 2 so that this actual negative acceleration AX becomes the determined negative acceleration An (steps 27 to 30). . That is, when the actual negative acceleration Ax is larger than the calculated negative acceleration An, the clutch 2 is disengaged (step 30); If it is smaller, the half-clutch connected state is controlled in the direction of connecting the clutch 2 so that the calculated negative acceleration An is achieved (step 28).

Also, the actual negative acceleration AX is the calculated negative acceleration A
If it matches n, the CPU 32 controls the connected state of the clutch 2 to maintain the half-clutch state at that time (step 29).

Therefore, in deceleration at this time, the negative acceleration An can be changed as appropriate according to the depression angle ex of the accelerator pedal 17.

Then, the forklift decelerates according to this negative acceleration An, reverses itself, starts traveling backwards, and completes the switchback traveling.

In this case, although the description has been made regarding traveling from forward to reverse, similar processing operations are performed such as switchback traveling from reverse to forward.

In this way, in this embodiment, the negative acceleration An can be changed as appropriate according to the depression angle ex of the accelerator pedal 17, so the reversal speed of switchback driving can be increased according to the driver's preference. Moreover, the negative acceleration An with respect to the depression angle ex of the accelerator pedal 17 is adjusted according to the load GX of the forklift, that is,
The larger the load GX is, the smaller the negative acceleration An with respect to the depression angle θX is, so ideal smooth deceleration is always possible regardless of the driver's skill and the presence or absence of a load, and the small output balance during deceleration is maintained. There is no risk that it will lose its weight and roll over.

Furthermore, in this embodiment, during switchback driving, the predetermined reference speed V1. Since the engine brake is applied to decelerate until V2 is reached, the automatic transmission 3 can be synchronized automatically to switch from 2nd gear to 1st gear and from forward to reverse for smooth back driving. Therefore, the automatic transmission 3 is not damaged, and the transmission can be smoothly switched for switchback driving regardless of the driver's skill.

Furthermore, in this embodiment, when the forward/reverse operation lever 20 is switched to neutral during driving, the automatic transmission 3 is not immediately shifted in response to the neutral, but is shifted during a predetermined time t. Since the driver is able to judge the driving (coasting driving, coasting shift driving, and switchback driving) that the driver is about to perform based on whether or not the next forward/reverse operation lever 20 is operated, the clutch switching drive means and It is possible to improve operability by eliminating unnecessary operations of the shift switching drive means of an automatic transmission, and
It is possible to reduce the burden on these driving means and improve durability.

Note that the present invention is not limited to the above-mentioned embodiment, and the set time t may be changed as appropriate within a range that does not impede driving, and the first and second reference speeds Vl, V may be changed as appropriate.
2 may be applied to a forklift truck with appropriate modifications, and the first and second reference speed V1. It may also be applied to a forklift truck in which V2 is set to the same value.

Furthermore, in deceleration control before switching from forward to reverse in switchback control, if the traveling speed VX at that time is large and it takes time to decelerate to the first reference speed v1, or if you want to decelerate faster, the CPU 32 Braking may be forcibly applied by controlling the drive of the disc brake. In this case, when the speed is above a predetermined speed, the disc brake is applied to decelerate, and when the speed is below the set speed, the disc brake is released.

Furthermore, in the embodiment described above, various negative accelerations An for the depression angle eX of the accelerator pedal 17 can be calculated according to the load Gx of the forklift, but this can be calculated as a negative acceleration An for a single depression angle θX regardless of the load Gx. It may also be applied to a forklift that is operated at an acceleration An of .

Furthermore, although the above embodiment was applied to a forklift,
Of course, the invention may be applied to other vehicles without departing from the spirit of the invention.

When the forward/reverse operating lever is switched to neutral, the automatic transmission does not immediately switch in response to the neutral, but instead determines whether or not the next forward/reverse operating lever is operated within a predetermined time. Since the driver's intention to operate the forward/reverse control lever is accurately determined based on the driver's intention to operate the clutch switching drive means and automatic transmission, It eliminates wasteful operation of the shift switching drive means and improves operability, as well as reduces the burden on these drive means and improves durability. It is an invention that has been developed since then.

[Brief explanation of the drawing]

Fig. 1 shows the structure of the drive system of a forklift that embodies this invention, Fig. 2 is an electric block circuit diagram of the forklift, and Fig. 3 shows the negative acceleration for each load with respect to the depression angle of the accelerator pedal. The figures showing the relationship, FIGS. 4 to 6, are flowcharts for explaining the operation of the forklift. In the figure, 1 is the engine, 2 is the dry single plate clutch, 3 is the automatic transmission, 6 is the clutch control actuator, 7 is the shift switching actuator, 8 is the forward/reverse switching actuator, 11 is the vehicle speed sensor, and 14 is the 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 is a load detection sensor, 24 is a cargo, 31 is a microcomputer, 32 is a central processing unit (CPtJ), 33 is a program memory, and 34 is a working memory. Patent applicant: Toyoda Automatic Machinery Co., Ltd. Fuji
General Co., Ltd. Agent Patent Attorney On 1) Concave chamber θX -111

Claims (1)

[Claims] When the direction point is switched to neutral by operating the forward/reverse operating lever, the clutch is disengaged and the forward/reverse operating lever is operated for a predetermined period of time without switching the automatic transmission. The automatic transmission and clutch are switched for switchback driving when the forward/reverse operating lever is switched to a direction point different from the direction point before switching to neutral. When the forward/reverse operation lever returns to the direction point before switching to neutral, the automatic transmission and clutch are controlled to shift to coasting, and the vehicle continues forward/reverse for a predetermined period of time. To provide a running determination method for a vehicle equipped with an automatic transmission, which controls switching of the automatic transmission and a clutch for coasting when there is no difference in direction points based on the operation of a control lever.