JPH0379817A - Failure detection for automatic clutch - Google Patents

Abstract

PURPOSE:To provide positive failure judgment all the time during the whole stroke of a clutch by making the allowable time which it takes to reach from a present position different according to the desired position of the clutch determined in a then traveling condition. CONSTITUTION:The allowable time of failure judgment is made different according to the desired positions of a clutch 2 determined by a sensor 9 based on a then traveling condition. In proximity G1, P1 to the connecting point and in proximity G3, P3 to complete connection which have severe influence on the speed change or traveling stopping of a fork-lift, it is possible to take safety measures for vehicle stopping and so forth by making prompt failure judgment in a short allowable time. In clutch disengagement ranges G2, P2 which have little influence, failure judgment is made in a long allowable time to prevent a vehicle from stopping many times due to some failure in the above range. It is thus possible to make positive failure judgment in an optimum allowable time all the time over the whole range during clutch stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a failure detection method for automatic clutches, and more particularly to a failure detection method that prevents false detection.

[Prior Art] Conventionally, in a vehicle equipped with an automatic transmission with a dry single-plate clutch, clutch operations associated with gear changes, starting, etc. are automatically performed using a clutch control actuator. Clutch operation by this actuator is performed by constantly moving the current clutch position (current position) to a clutch position (target position) determined based on the current driving state.

Further, in such an automatic transmission, a failure of the clutch control actuator is detected. That is, when operating the clutch, a timer measures whether the current position has reached at least a predetermined vicinity of the target position within a predetermined allowable time, and if the current position has not reached the target position within the allowable time, the clutch control The system determines that the actuator is malfunctioning and stops the vehicle or lights up a warning lamp.

[Problems to be Solved by the Invention] However, during the entire stroke of the clutch, there are areas where accuracy is required for the operation, such as near the connection start point (where the current position needs to accurately follow the phonetic position). There is a certain range (region where the current position does not need to follow the target position very accurately) and a range where the accuracy of the operation is not required as long as the clutch is disengaged, such as near the complete disengagement (a range where the current position does not need to follow the target position very accurately).However, as mentioned above, In automatic transmissions, the allowable time is set to a fixed value, so if the allowable time is set to a long value, the detection of clutch malfunction that occurs in important areas such as near the starting point of the connection will be delayed;
If the permissible time is set short, there is a problem in that clutch malfunctions occurring in less important areas, such as near complete engagement, will be frequently detected.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic clutch failure detection method that can always perform accurate failure determination during the entire stroke of the clutch.

[Means for Solving the Problems] The present invention provides clutch control to move a clutch that turns on and off the output of the engine and transmits the output to the transmission from its current position to a target position determined based on the driving condition at that time. 7
A timer measures whether the actuator has reached at least a predetermined vicinity of the target position within a predetermined allowable time, and if the actuator has not reached the target position within the allowable time, it is determined that the actuator has failed. The gist of the automatic clutch failure detection method is to vary the allowable time depending on the target position.

[Effect] Since the allowable time is made different depending on the target position, for example, if the target position has a significant effect on the running of the vehicle, the allowable time is shortened, and conversely, the allowable time is shortened if the target position has an important influence on the running of the vehicle. In the case of a target position, by increasing the allowable time, the determination of clutch movement to an important target position is made quickly, and the determination of clutch movement to a less important target position is made slowly.

[Example] Hereinafter, an example in which the present invention is embodied in a forklift equipped with an automatic transmission with a dry single-plate clutch will be described with reference to the drawings.

FIG. 1 shows the mechanism and electrical configuration of a forklift drive system. The output of an engine 1 is transmitted to an automatic transmission 3 via a dry single-plate clutch 2, and the automatic transmission 3 is controlled by a differential gear mechanism 4.
The running drive wheels 5 are moved forward and backward at a predetermined gear ratio via the drive wheels 5.

The throttle III l actuator 6 opens and closes a throttle valve (not shown) of the engine 1, and the engine speed is controlled accordingly. The seven actuators 7 for the clutch υJlj maintain the connected state of the dry single plate clutch 2 by 111 m according to the stroke amount of the rod 7a. Moreover, the gear switching actuator 8 is the first gear of the automatic transmission 3,
It performs switching between two positions of 2nd speed and switching between three positions of forward, neutral, and reverse.

The stroke detection sensor 9 consists of a potentiometer,
The stroke amount of the rod 7a of the clutch control actuator 7 is detected, and the detection signal is sent to the A/D converter 10.
The signal is converted into a digital signal and output to the input/output interface 11.

Vehicle speed sensor 12 detects the rotational speed of output shaft 3 a of automatic transmission 3 and outputs the detection signal to input/output interface 11 . The input shaft rotation speed sensor 13 detects the rotation speed of the input shaft 3 b of the automatic transmission 3 and outputs the detection signal to the input/output interface 11 .

Further, the accelerator sensor 14 consists of a potentiometer,
The amount of depression of an accelerator pedal 15 provided at the driver's seat is detected, and the detected signal is digitally converted by an A/D converter 16 and output to the input/output interface 11. The lever position detection sensor 17 detects the FJJ (forward, neutral, reverse) of the forward/reverse operation lever 18 provided at the driver's seat, and outputs the detection signal to the interface 11. A warning lamp 19 is provided at the driver's seat to indicate a failure of the clutch control actuator 7.

A central processing unit 20 (hereinafter referred to as CP LJ) receives detection signals from each of the sensors via the input/output interface 11. The CPU 20 operates according to a control program stored in a program memory 21 consisting of a read-only memory (ROM). Further, the working memory 22 is a readable and paraphraseable memory (RAM), and is adapted to temporarily store the calculation results of the CPU 20.

Then, the CPU 20 drives and controls the throttle control actuator 6 via the actuator drive circuit 23,
The throttle valve of the engine 1 is opened and closed in accordance with the depression of the accelerator pedal 15.

In addition, CPtJ20 is connected to the actuator drive circuit 2 during driving.
4 to drive and control the gear switching actuator 8,
The automatic transmission 3 is switched to one of the first and second gear positions in accordance with the amount of depression of the accelerator pedal 15 relative to the vehicle speed. Further, the CP 20 operates the forward/backward operating lever 1 based on the detection signal from the lever position detection sensor 17.
8 is determined, and the gear switching actuator 8 is driven and controlled via the actuator drive circuit 24 according to the switching state, and the automatic transmission 3 is set to forward, neutral, or forward.
Switch to any reverse gear position.

Furthermore, the CPU 20 drives and controls the clutch control actuator 7 via the actuator drive amount 25 when changing the gear position or starting the forklift as described above, and causes the dry single-plate clutch 2 to engage and disengage. For this purpose, the CPU 20 determines the current position, which is the current connected state of the clutch 2, based on the detection signal from the stroke detection sensor 9, and reads out the target position from the clutch control data stored in the program memory 21. When the clutch 2 is connected or disconnected, the clutch control actuator 7 is controlled so as to always move the current position of the clutch 2 to the target position.

The program memory 21 stores in advance the positions of the rod 7a of the clutch control actuator 7 as set values when the clutch 2 is in six different connected states. Figure 3 shows the positional relationship of each set value during the entire stroke of clutch 2. As shown in the figure, each set value changes from the fully engaged position of clutch 2 to G3, P3, Pl, Gl.
.

In the following description, for convenience's sake, it is assumed that the value increases as the target position and the current position move toward the disengaged side of the clutch 2. Therefore, each of the above settings (the size relationship of white is G3
<P3<Pl <G1 <P2<G2.

If the CPU 20 determines that the current position does not reach 11 or more within a preset allowable time of 12 when the target position is 01 or more, it determines that the clutch control actuator 7 has malfunctioned. Further, the warning lamp 19 is turned on and the throttle control actuator 6 is driven and controlled to fully close the throttle valve.

Similarly, when the target position is 02 or more, the CPLJ20 has an allowable time Tl (>
If it is determined that the current position does not reach 12 or more within T2), it is determined that the clutch control actuator 7 has malfunctioned and is determined to be malfunctioning. Further, the warning lamp 19 is turned on and the throttle control acticoator 6 is driven and controlled to fully open the throttle valve.

On the other hand, if the CPU 20 determines that the current position does not become less than 13 within a preset allowable time of 12 when the target position is G3 (complete engagement), the CPU 20 determines that the clutch control actuator 7 has malfunctioned. Further, the warning lamp 19 is turned on and the throttle control actuator 6 is driven and controlled to fully open the throttle valve.

Next, the failure detection operation of the clutch control actuator 7 performed by the CPU 20 will be explained according to the flowchart shown in FIG.

Now, based on the driving condition at that time, G3 (<G2゜Gl
) is set and the actuator 7 starts operating based on the target position, each timer 1 to 3 is cleared and the second
The CPU 20 executes processing operations according to the flowchart. In step 1, it is determined whether the target position is 01 or more, and since the target position [(-G3) is less than G1, in step 3, timer 1 is cleared and the process moves to step 5.

Subsequently, in step 5, it is determined whether the target position is 02 or more, and since the target position (=G3) is less than 02, in step 7, timer 2 is cleared, and the process moves to step 9.

Next, in step 9, it is determined whether the target position is 03, and since the target position (=G3) is 03, subsequently, in step 10, it is determined whether the current position is greater than or equal to the set position 13.
That is, it is determined whether the current position is a distance of P3 or more from the target position (=G3). And the current position is P3
If the actuator 7 is closer to the contact side, the timer 3 is cleared in step 11, assuming that the actuator 7 is operating normally and is reaching the target position. On the other hand, if the current position is newer than P3, the timer 3 is incremented by one in step 12, assuming that the actuator 7 has not reached the target position.

Now, assuming that the target position has not been reached, timer 3
After adding 1, each timer 1 is added in steps 13 to 15.
~3 counts (T between each predetermined allowable FR)
l (=6), T2 (=2> or more. At this time, since the allowable time T1 and T2 have not been reached, respectively, go to step 1 again and execute the above and @-like processing. do.

Then, in steps 9 and 10, the current position is more than P3 r from the target position (=G3)! It is determined whether or not the current position is on the fI side, and if the current position is on the tangential side of P3, the timer 3 is cleared in step 11, assuming that the actuator 7 is operating normally and is reaching the target position. On the other hand, if the current position is newer than P3, it is assumed that the actuator 7 has not reached the target position, and the timer 3 increments the count value by one to make the count value "2".

Therefore, when the target position is G3 (complete connection), if the current position is less than 13, that is, does not reach the contact side from P3 before the count value of timer 3 reaches r2J, step 1
At step 6, it is determined that the actuator 7 has malfunctioned and is not in a normal connection state, and the alarm lamp 19 is turned on and the throttle is fully closed.

Next, G2 (>01, G
3) When the above target position is set and the actuator 7 starts operating based on the target position, in step 1, it is determined that the target position (>G2) is 01 or more,
In step 2, it is determined whether the current position is less than the set position JP1, that is, whether the current position is located on the tangent side of Pl.

Since P1 and 02 are set far apart, even if the actuator 7 has some malfunction, when a target position of 02 or higher is set, the current position will be at least above P11X, that is, below Pl. It can be assumed that it has reached the cut side. Therefore, unless a serious malfunction occurs in the actuator 7, the CPLJ 20 clears the timer 1 in step 3 and proceeds to step 5.

Next, in step 5, the target position (>G2> is 02
It is determined that the above is the case, and the process moves to step 6.

In step 6, whether the current position is less than the set position 92,
That is, it is determined whether the current position is on the contact side of P2 or not, and if the current position is on the distal side of P2, the timer 2 is determined to indicate that the actuator 7 is operating normally and is reaching the target position in step 7. Clear. On the other hand, the current position is P2
If it is closer to the contact side, in step 8, it is determined that the actuator 7 has not reached the target position, and the timer 2 is increased by one.

Then, after clearing timer 3 in step 11, in steps 13 to 15, the count values of each timer 1 to 3 are set to the predetermined allowable Ff# interval TI (=
6), it is determined whether or not T2 (=2) or more has been reached, and the process returns to step 1 to execute the same process as described above.

Thereafter, in step 5.6, it is determined whether the current position is less than P2 or not, and if it is not 22 or more, this processing operation is repeated until the count of timer 2 reaches "6".

Therefore, when the target position is 02 or more, if the current position does not reach 22 or more, that is, the incision side from P2, before the count value of timer 2 reaches "6", the actuator 7 is activated in step 16. It is determined that a malfunction has occurred and the connection is not in a normal state, and the warning lamp 19 is turned on and the throttle is fully opened.

On the other hand, in step 2, the current position is the set position 11.
If the value is less than 1, that is, if the actuator 7 has a serious malfunction, the CPU 20 proceeds to step 4 and increments the timer 1 by one. Further, as described above, the CPU 20 increments timer 2 by one in step 8, clears timer 3 in step 11, and then clears timer 3 in steps 13 to 15.
In the same way as above, the count values of each timer 1 to 3 are set to predetermined allowable times T1 (=6) and T2 (=2), respectively.
Determine whether or not the above has been reached, and proceed to step 1 again.
Execute the same process as above.

Therefore, in this case, timer 1 and timer 2 count up simultaneously. Then, the count value of timer 2 is “
Since it is faster for the count value of timer 1 to reach ``2'' than to reach ``6,'' if the current position does not reach 21 or more, that is, a new position than Pl, before the count value of timer 1 reaches 12. In step 16, it is determined that the actuator 7 has malfunctioned and is not in a normal connection state, and the alarm lamp 19 is turned on and the throttle is fully opened.

Next, G1 (<G2>-
When the above target position is set and the actuator 7 starts operating based on the target position, it is determined in step 1 that the target position is 01 or more, and the process moves to step 2. In step 2, it is determined whether the current position is less than the set position 11, that is, whether the current position is on the tangent side of Pl, and if it is at the new position, in step 3, the actuator 7
clears timer 1 assuming that it is operating normally and is reaching the target position. On the other hand, if the current position is on the tangent side of Pl, in step 4, it is determined that the actuator 7 has not reached the target position, and the timer 1 is incremented by one.

Then, after clearing timer 2 in step 8 and clearing timer 3 in step 11, steps 13 to 15
In the same way as above, it is determined whether the count values of each timer 1 to 3 have exceeded the predetermined allowable times T1 (=6) and T2 (=2), respectively, and the process returns to step 1. Execute similar processing.

Thereafter, in step 1.2, it is determined whether the current position is less than 11, and if it is not 21 or more, this processing operation is repeated until the count value of timer 1 becomes "2".

Therefore, when the target position is 01 or more, if the current position does not reach 21 or more, that is, the incision side from Pl, before the count value of timer 1 becomes "2", the actuator 7 is activated in step 16. It is determined that a malfunction has occurred and the connection is not in a normal state, and the warning lamp 19 is turned on and the throttle is fully opened.

The reason for distinguishing the allowable times into T1 and T12 as described above is that when the conditions of steps 1 and 2 are satisfied, clutch 2 should be disengaged, but in reality it is not at the connection point. This means that it is on the tangent side of a certain Pl and is not broken. As a result, if the clutch is operated to change gears, the gears cannot be changed, and if the clutch is operated to stop the vehicle, power continues to be transmitted to the driving drive wheels 5 and the forklift cannot be stopped. There is a possibility that this will happen. Therefore, in such a case, in this embodiment, a failure determination is made quickly within a short allowable time T2.

Also, when the conditions of steps 5 and 6 are satisfied, P2
is set fairly recently, so the current position is less than 12, that is, although it is on the contact side from P2, it is considered to be on the disconnection side from the connection start point P1.

Therefore, it is estimated that clutch 2 is actually disengaged,
There is no possibility that the above-mentioned situations such as the inability to shift gears or the inability to stop the vehicle will occur, and there is no need to urgently deal with such situations. Moreover, if the forklift frequently stops due to such a situation, the original transportation work will be hindered. Therefore, in such a case, in this embodiment, a failure determination is made within a relatively long allowable time T1.

On the other hand, when the conditions of steps 9 and 10 are satisfied,
Although clutch 2 should be fully engaged, it is actually in a half-clutch state, and clutch 2
There is a risk of wear and tear due to slippage and poor acceleration of the vehicle.

Furthermore, since P3 is set at a position quite far from G3, which is the fully connected position, a failure determination will not be made unless the current position is significantly behind the target position. Therefore,
There is very little possibility that a failure determination will be made incorrectly. Therefore,
In such a case, in this embodiment, a failure determination is quickly made within a short allowable time T2.

In this way, in this embodiment, the target position Gl.

G2. Allowable time T1 according to G3. Because T2 is set to be different, failures occur quickly within a short allowable time T2 near the connection start point (G1.Pl) and near the complete connection (G3.P3), which have a significant impact on the shifting, running, and stopping operations of the forklift. Once the judgment is made, safety measures such as stopping the vehicle can be taken. In addition, in the clutch disengagement region (02, P2) which does not have such a serious effect, the long allowable time T
A failure determination is made in step 1, and it is possible to prevent the vehicle from frequently stopping due to a malfunction in this area. Therefore, the allowable time T1. is always optimal in all regions during the clutch stroke. Failure can be accurately determined at T2.

Note that the present invention is not limited to the above-mentioned embodiments. For example, the gist of the present invention may be modified by setting T3 in addition to Tl and T2 as the allowable time, or setting the current position P3 to be newer than Pl. Any changes may be made within the range.

[Effects of the Invention] As described in detail above, the automatic clutch failure detection method of the present invention provides an excellent effect in that accurate failure determination can always be made during the entire stroke of the clutch.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the mechanism and electrical configuration of the forklift drive system, Fig. 2 is a flowchart to explain the operation, and Fig. 3 is an explanation showing the positional relationship of each setting value during the entire stroke of the clutch. It is a diagram. 1 is the engine, 2 is the clutch, 3 is the automatic transmission, 7 is the clutch control actuator, P1~P3゜01~G3
is the set value, and Tl and T2 are the allowable times.

Claims (1)

[Claims] The clutch, which turns on and off the output of the engine and transmits the output to the transmission, is moved from the current position to a target position determined based on the driving condition at that time using a clutch control actuator, which is set in advance. The automatic clutch uses a timer to measure whether the target position has reached at least a predetermined vicinity within the permissible time, and if the target position has not been reached within the permissible time, it is determined that the actuator has failed. A failure detection method for an automatic clutch, wherein the allowable time is varied depending on the target position.