JPH0379860A - Failure detecting method for gear shift actuator for transmission - Google Patents

Abstract

PURPOSE:To detect failure accurately by detecting the operating quantity of a gear shift actuator at gear shifting, adding the count value of the retry action executed frequency when the detected value is less than the set value, and detecting the failure when the count value reaches the specified frequency. CONSTITUTION:In the case the gear position cannot be changed and retry action is performed, a CPU 21 compares the operating quantity detected at the detector 9 of a gear shift actuator 7 with the set value. When the operating quantity is less than the set value, a figure 1 is added to the executed frequency of the continuous retry action, and the count value is stored in a working memory 23. When the count value reaches the specified value, the failure of the gear shift actuator is judged and informed by the lighting of a first and a second alarm lamps 19, 20, as well as avoiding action is performed. The failure of the gear shift actuator 7 is thus detected always accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a failure detection method for a gear switching actuator of a transmission, and more particularly to a failure detection method that prevents erroneous detection.

[Prior Art] Conventionally, in a transmission in which a gear position is changed by a gear switching actuator, there is a transmission that automatically detects a failure of the gear switching actuator. That is, since such a transmission performs a retry operation in which, when a gear change is impossible, the gear position is returned to the position before the change operation, and then the gear position is changed again to a predetermined gear position.
If the gear switching is not completed even after performing this retry operation a predetermined number of times, it is determined that a failure has occurred in the gear switching actuator, the vehicle is stopped, and a warning lamp on the driver's seat is turned on. There is.

[Problems to be Solved by the Invention] However, the cause of inability to change gears, that is, the cause of retry operation, is gear 1. In addition to malfunctions of the IJ switching actuator, failures can also occur due to poor gear meshing, and the above-mentioned failure detection method simply detects failure of the gear switching actuator even when gear meshing defects occur several times. Sometimes I put it away. Therefore, a problem arises in that even a trivial problem such as gear meshing failure causes the vehicle to stop and become unable to travel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting a failure in a gear switching actuator of a transmission, which can always accurately detect a failure in a gear switching actuator without causing erroneous detection.

[Means for Solving the Problems] In the present invention, when the gear position of a transmission is changed by a gear change actuator and the gear position cannot be changed despite a change operation, when the gear change is impossible, the gear position before the change operation is changed. A retry operation is performed to temporarily return to the gear position and switch to a predetermined gear position again, and the number of times the retry operation is performed continuously is counted. When the count value reaches a predetermined number, the gear position is In a transmission that determines that the seven switching actuators are malfunctioning and performs an avoidance operation, the operating amount of the gear switching actuator at the time of gear switching is detected by an operating amount detection means, and the operating amount is set in advance. Failure detection of a gear switching actuator of a transmission in which the count value is added when the actuation amount is less than the set value, and the count value is not added when the actuation amount is greater than the setting IiIg. The gist is the method.

[If the working cogear position cannot be changed and a retry operation is performed, the actuation amount of the gear switching actuator is compared with a preset value.

When the amount of operation is less than the set value, the count value is added, and when the amount of operation is greater than or equal to the set value, the count value is not added. When the count value reaches a predetermined number, it is determined that the gear switching actuator is malfunctioning, and an avoidance operation is performed. Therefore, if the retry operation is simply continued, a failure determination of the gear switching actuator is not made, and no avoidance operation is performed.

[Embodiment 1] Hereinafter, an embodiment in which the present invention is embodied in a forklift truck equipped with an automatic transmission will be described with reference to the drawings.

Figure 1 shows the mechanism of the drive system of a forklift, and the output of the engine 1 is automatically shifted via a dry single plate clutch 2.
3, and the automatic transmission 3 moves the traveling drive wheels 5 forward and backward at a predetermined gear ratio via the differential gear mechanism 4. The connected state of the dry single plate clutch 2 is adjusted by a clutch ill actuator 6.

Further, the automatic transmission 3 can change its gear position between 1st speed (faster, lower speed) and 2nd speed (higher speed) by driving the speed change switching actuator 7, and change the gear position by driving the forward/reverse switching actuator 8. Forward, neutral, reverse 3
The position can be changed.

The shift position detector 9 consists of a potentiometer, and detects three positions, 1st gear, neutral, and 2nd gear, based on the position of the rod 7a of the shift switching actuator 7, and the detection signal is sent to the A/D converter 9a. The signal is digitally converted and output to the input/output interface 10 (shown in FIG. 2).

Further, the forward/reverse position detector 11 is composed of a potentiometer, and detects the three positions of forward, neutral, and reverse based on the position of the rod 8a of the forward/reverse switching actuator 8, and its detection signal is sent to the A/D converter 11a. The signal is converted into digital data and output to the input/output interface 10. Furthermore, what are the gear shift position detector 9 and the forward/reverse position detector 11? 1IJN detecting means is constituted, and as described later, the Otsudo 7 of the actuator 7.8 for shifting gears and forward/forward switching.
A, movement amount ΔL of 8a (actuation W of both actuators 7.8
Jfi) is also used for failure detection of each actuator 7.8.

The vehicle speed sensor 12 is designed to detect the rotational speed of the output shaft 3a of the automatic transmission 3. Further, the input shaft rotation speed sensor 13 is designed to detect the rotation speed of the input shaft 3b of the automatic transmission 3. Further, a throttle valve (not shown) of the engine 1 is opened by a throttle control actuator 18, and the engine speed is controlled accordingly.

Next, the electrical configuration of the forklift will be explained according to FIG. 2.

The accelerator sensor 14 is composed of a potentiometer and detects the depression of an accelerator pedal 15 provided at the driver's seat, and the detection signal is converted into digital data by an A/D converter 14a and output to the input/output interface 10. .

Further, the lever position detection sensor 16 detects the switching state B (forward, neutral, reverse) of the forward/reverse operation lever 17 similarly provided at the driver's seat, and outputs the detection signal to the interface 10.

The central processing unit 21 (hereinafter referred to as CPLI) inputs detection signals from the tJ notation structure detector and sensor via the input/output interface 10. The CPU 21 has a program memory 22 consisting of a read-only memory (ROM).
The controller operates according to a control program stored in the controller. Note that the working memory 23 is a readable and rewritable memory (R
AM), which temporarily stores the calculation results of the CPU 21.

Then, the CPU 21 drives and controls the throttle control actuator 18 via the actuator drive circuit 24, and opens and closes the throttle valve of the engine 1 according to the depression level of the accelerator pedal 15.

Further, the CPU 21 drives and controls the gear change actuator 7 via the actuator drive circuit 24 during driving, and in this embodiment, changes the automatic transmission 3 to 1st or 2nd gear depending on the amount of depression of the accelerator pedal 15 with respect to the vehicle speed. The gear position is controlled to switch to one of the two speeds.

Furthermore, CPtJ2'' is the lever position detection sensor 16.
The switching state of the forward/reverse operation lever 17 is determined based on the detection signal from the forward/reverse operation lever 17. Then, the CPU 21 drives and controls the forward/reverse switching actuator 8 via the actuator drive circuit 24 according to the switching state, and switches the automatic transmission 3 to one of the forward, neutral, and reverse gear positions I5!
It is meant to be controlled.

On the other hand, the CPU 21 controls the clutch control actuator 6 via the actuator drive circuit 24 during the above switching.
, and causes the dry single plate clutch 2 to engage and disengage.

Furthermore, when changing gears between the first and second speeds described above, the CPU 21 determines whether the gear has been changed to the target gear based on the detection signal from the shift position detector 9, and selects between forward, neutral, and reverse. When changing gears, it is determined whether the gear has been changed to the target gear based on the detection signal from the forward/reverse position detector 11. In any case of gear switching, if the gear switching is not completed even after a predetermined period of time has elapsed, the gear is temporarily returned to the gear position before shifting. At this time, in the case of neutral, the dry single plate clutch 2 is momentarily connected to achieve synchronization, and then the gear is switched again to the predetermined gear position (retry operation).
Determines the amount of movement ΔL of the rods 7a and 8a of the actuator 7.8 for speed change and forward/reverse change based on the detection signals from the shift position detector 9 and the forward/reverse position detector 11, and determines the amount of movement ΔL. A failure of each actuator 7.8 is detected based on.

Further, first and second warning lamps 19 and 20 are provided at the driver's seat of the forklift, and the first warning lamp 19 indicates a malfunction in the gears of the automatic transmission 3.
is the actuator 7 for shifting and forward/forward switching.
The system is designed to notify the driver of each of the 8 failures.

Next, the CPU 21 operates the gear shift switching actuator 7.
The failure detection operation will be explained according to the flowchart shown in FIG.

First, when the CPtJ21 determines that gear switching between 1st and 2nd speeds is to be performed in step 1, the error counter is cleared in step 2, and the shift position 1d detector 9 is detected in step 3.
The position P1 of the rod 7a of the speed change switching actuator 7 before the gear change is determined based on the detection signal from the , and the position data is stored in the working memory 23. CPU
21 clears and starts the timer in step 4, and in step 5 drives and controls the gear shift switching actuator 7 to move the gear position to the target position (if the current gear position is 1st gear, it shifts to 2nd gear; If so, switch to 1st speed.

Then, in step 6, the CPU 21 determines whether the gear position has been switched to the target position based on the detection signal from the shift position detector 9, and when the gear position has been switched, this series of gear switching processing is completed. On the other hand, if the switching is not possible, the process moves to step 7 and it is determined whether or not a preset time T1 has elapsed, and if the time has not elapsed, the process returns to step 6. Further, when the time T1 has elapsed in step 7, the process moves to step 8. Therefore, time T
If the gear position is not switched to the target position within 1 time, the CPLI 21 moves to step 8.

In step 8, the CPtJ21 determines the current position P2 of the rod 7a of the shift switching actuator 7, and determines the difference between the position P2 of the rod 7a and the position P1 of the rod 7a before shifting, that is, the amount of movement ΔL of the rod 7a. (=I P2-
Pl 1 ) is determined. Furthermore, the CPLI 21 sets the movement amount ΔL obtained in step 9 to a predetermined setting value L1.
When ΔL is larger than ΔL, the process moves to step 10. In this case, the CPIJ 21 determines that the gears do not mesh for some reason, although the shift actuator 7 is being driven, and executes the following process.

In step 10, the CPU 21 sets the first error counter to "
1'' is added, and in step 11 it is determined whether this first error counter is equal to or greater than the set value 01. When the first error counter is less than the set value 01, the CPU 21 performs step 1.
At step 2, the gear position is returned to the position before switching, and the process returns to step 3 described above. Then, the CPU 21 performs this step 3.
The process from step 12 to step 12 (retry operation) is repeatedly performed, and when switching to the target position is completed in step 6, this series of processes is completed, and if the switching is not completed, the number of repetitions is set to the set value in step 11. When C1 is reached, the process moves to step 13.

Then, in step 13, the CPU 21 determines that the cause of the inability to change the gear position is poor meshing of the gears, and in step 14 lights up the first warning lamp 19. Therefore, by lighting the first warning lamp 19, the driver can be informed of gear meshing failure.

On the other hand, if the movement amount ΔL is equal to or smaller than the set value 1 in step 9, the CPU 21 proceeds to step 15. In this case, the CPU 21 determines that a failure has occurred in the gear shift switching unit 7 and that it is not being driven, and the CPU 21 executes the following process.

The CPU 21 sets the second error counter to 1 in step 15.
is added, and in step 16 it is determined whether this second error counter is equal to or greater than the set value 02.

When the second error counter is less than the setting 1FJ02, C
In step 12, the PU 21 returns the gear position to the position before switching, and repeats the retry operation from step 3 to step 12. Then, when the switching to the target position is completed in step 6, the CPU 21 ends this series of processing, and when the switching is not completed and the number of repetitions reaches the set value C2 in step 16, the CPU 21 moves to step 17. do.

Then, in step 17, the CPtJ 21 determines that the cause of the inability to change the gear position is due to a failure in the gear shift switching actuator 7, and in step 18, the CPtJ 21 lights up the second warning lamp 20, and also turns on the throttle control actuator 18. to fully open the throttle valve of engine 1.

Therefore, by lighting the second warning lamp 20, the driver can be informed of the failure of the gear shift switching actuator 7, and can also automatically stop the running forklift to prevent an accident.

Note that the CPU 21 also uses the rod 8 detected by the reverse position detector 11 for the forward/reverse switching actuator 8.
The failure is determined based on the movement I6ΔL of a, but the process is performed by the shift switching actuator 7 described above.
Since this is exactly the same as in the case of , the explanation will be omitted.

In this way, in this embodiment, the shift position detector 9 and the forward/reverse position detector 11 detect the amount of movement ΔL of the rods 7a, 8a of the actuators 7, 8 for shifting and forward/reverse switching when changing gears. Then, the moving amount ΔL is compared with a preset value 1, and if the moving amount ΔL is less than the set value 1, the count value of the second error counter is added and the moving loss ΔL/% is calculated. When setting @11 or higher, the count value of the second error counter is no longer displayed. Furthermore, the count f+ti is a predetermined number 02
When this is reached, the actuator 7.8 for shifting gears or forward/reverse switching is determined to be malfunctioning, and an evasive action such as stopping the forklift is performed.

As a result, if the movement amount ΔL is greater than or equal to the setting (i1111), it is determined that the cause of the inability to switch gears is actuator 7.
It is assumed that this is not due to a malfunction in item 8, but rather a minor malfunction that does not interfere with the operation of the forklift, such as a gear misalignment.
The count value of the second error counter is not adjusted. Therefore, even if the gears cannot be changed due to poor gear meshing, the failure of the actuator 7.8 is not determined, and the forklift does not become unable to travel, so its transport work is not interrupted.

In addition, the first warning lamp 19 is turned on when the cause of the inability to change gears is poor gear meshing, and the second warning lamp 20 is turned on when there is a failure in the actuator 7.8, thereby saving operation. can easily and accurately determine the cause of the inability to change gears and deal with the problem.

Note that the present invention is not limited to the above-mentioned embodiments; for example, although the above-mentioned embodiments are directed to an automatic transmission that automatically switches between 1st speed and 2nd speed, the present invention is not necessarily limited to an automatic transmission. There's no need. Therefore, in the forklift of the above embodiment, switching between the first speed and the second speed may be performed using an operating lever on the driver's seat in the same way as forward and backward movement.

Also, actuator 7.8 for speed change and backward movement change.
Although the failure determination was made based on the movement amount Δ[ of the front doors a and 8a, the failure judgment may be made based on the actual movement amount of the gear, for example.

Further, the set value L1. CI and C2 can be set arbitrarily according to the specifications of automatic transmission, for example, actuator 7
．． The setting il@C2 for determining the failure of 8 may be set to once. In addition, the setting v1c2 may be set for each target position of gear switching. For example, when switching gears to 1st speed, there is little danger even if the gear cannot be changed, so the setting (fIC2) may be set to ensure failure determination. The setting value C2 may be set to 5 times, and the setting value C2 may be set to 1 time in order to quickly determine a failure since it is dangerous if the switch is not possible when switching to neutral.

On the other hand, in the forklift of the above embodiment, when the travel amount ΔL of the rod 7a is larger than the set value 1 in step 9 and the cause of the inability to change gears is due to poor meshing of the gears, steps 10 to 14 are performed. These processes are executed to light up the first warning lamp, but if these processes are omitted and the step movement amount ΔL is greater than the set value L1, the process directly proceeds to step 12 and the retry operation is repeated. You can do it like this.

[Effects of the Invention] As detailed above, according to the method for detecting a failure in a gear changing actuator of a transmission according to the present invention, failures in a gear changing actuator can always be accurately detected without causing false detection. It exerts a pervasive effect.

[Brief explanation of drawings]

FIG. 1 is a mechanical diagram showing the mechanism of a drive system of a forklift embodying the present invention, FIG. 2 is an electrical block diagram of the forklift, and FIG. 3 is a flowchart for explaining the operation. 3 is an automatic transmission, 7 is a gear switching actuator as a gear switching aquayuator, and 8 is a gear switching actuator 1.
9 is a shift position detector as an actuation amount detection means, 11 is a forward/reverse position detector as an actuation amount detection means, ΔL is a movement amount, Ll
, C2 is a set value.

Claims (1)

[Claims] 1. When the gear position of the transmission is changed by the gear change actuator and the gear position cannot be changed despite the change operation, the gear position is returned to the gear position before the change operation and the gear position is again set to the specified gear position. The gear switching actuator is determined to have a failure when the count value reaches a predetermined number. In a transmission that performs avoidance operation,
The actuation amount of the gear switching actuator at the time of gear switching is detected by the actuation amount detection means, and the actuation amount is compared with a preset setting value, and when the actuation amount is less than the set value, the count value is set. A failure detection method for a gear switching actuator of a transmission in which the count value is added and the count value is not added when the operating amount is greater than a set value.