JPH02221723A - Travel speed controller for vehicle - Google Patents

Abstract

PURPOSE:To improve riding quality by determining a degree of connection value to a car speed deviation and its changing portion on the basis of stored connection value data when a clutch is adjusted to a specified half-connecting state and actual car speed is gradually approximated to the desired value. CONSTITUTION:A central processing unit 22 of a controller 21 determines a desired car speed conformed to the manipulated variable of an accelerator pedal 16 being detected by an accelerator sensor 15 on the basis of car speed data of a memory 24, and it calculates a deviation with car speed by a car speed sensor 14 in addition to its changing portion. In order to be controlled to the desired car speed indicated, when a fact that a clutch 2 is adjusted to a specified half-connecting state being detected by a stroke sensor 11 and actual car speed is gradually approximated to the desired car speed if discriminated, a degree of clutch engaging value to the car speed variation and its changing portion is determined from the data of the memory 24, controlling the engaged value of the clutch 2 via a drive circuit 26 and an actuator 8, and it is converged on the desired car speed. Thus, it is possible to improve riding quantity without changing a clutch engaged state frequently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a traveling speed control device commonly used in vehicles such as forklifts.

[Prior Art] Conventionally, many cargo handling vehicles such as forklifts use a single engine as both a drive source for traveling and a drive source for cargo handling. That is, based on that one engine, the drive wheels are driven through a clutch and a transmission, and the cargo handling hydraulic pump is driven to operate each cargo handling cylinder such as a lift cylinder and a tilt cylinder via a hydraulic circuit. It looks like this.

Therefore, in order to obtain the desired engine output associated with cargo handling operations, the engine speed is controlled based on the amount of operation of the operating means such as the cargo handling lever, and the fluctuation in traveling speed based on the control of the engine speed is controlled by pressing the accelerator pedal. A speed control device for cargo handling operations has been proposed that is configured to control the clutch transmission torque or the brake force by 1 in order to adjust the traveling speed to the amount of travel.
Publication No. 5).

According to this speed control device, the traveling speed during cargo handling operations can be arbitrarily controlled by operating the cargo handling lever etc. and the accelerator pedal. It was possible to eliminate the inching pedal used for cargo handling, and improve the operability of cargo handling operations.

[Problems to be Solved by the Invention] However, in the speed control device, there is room for improvement in terms of ride comfort due to travel speed control. That is,
In order to converge the traveling speed to a desired speed, the clutch transmission torque is controlled by controlling the clutch drive means, etc., but at this time, the amount of clutch engagement is changed, which may cause discomfort to the driver. It had become.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to maintain the clutch in a predetermined half-engaged state in order to maintain a comfortable ride and to converge to the traveling speed instructed by an operating means such as an accelerator pedal. An object of the present invention is to provide a vehicle running speed control device that can control the speed of a vehicle.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a clutch drive means for adjusting the connection state of the clutch that turns on and off the output from the engine to the transmission, and a vehicle running speed. and an accelerator operation amount detection means for detecting the amount of operation of an accelerator operation means operated to instruct the traveling speed, in order to control the traveling speed to the one instructed by the accelerator operation means. , in a vehicle traveling speed control device that adjusts a clutch to a predetermined half-connected state, a detection operation is performed by a vehicle speed data storage means that stores in advance a vehicle speed corresponding to an operation amount of an accelerator operation means as vehicle speed data, and an accelerator operation amount detection means. a vehicle speed deviation calculation means for determining a target vehicle speed for a given amount based on vehicle speed data and calculating a vehicle speed deviation between the target vehicle speed and an actual vehicle speed detected by the vehicle speed detection means; and a change in the vehicle speed deviation before and after a predetermined elapsed time. a vehicle speed deviation change calculation means for calculating the vehicle speed deviation, and data instructing the degree of engagement of the clutch with respect to the vehicle speed deviation and the change in the vehicle speed deviation, wherein the degree of engagement of the clutch does not change as appropriate with respect to the vehicle speed deviation and the change in vehicle speed deviation. A connection amount data storage means that stores data having a region in advance as connection amount data, a multi-connection determination means that determines whether or not the actual vehicle speed has asymptotically approached the target vehicle speed, and the clutch is in a predetermined half-connected state. When the actual vehicle speed is determined to have asymptotically approached the target vehicle speed by the multiple connection determination means, in order to converge the actual vehicle speed to the target vehicle speed, the vehicle speed deviation calculated by the vehicle speed deviation calculation means and the vehicle speed deviation change calculation means are A clutch that determines a degree of engagement of the clutch with respect to a change in vehicle speed deviation calculated based on connection amount data stored in a connection amount data storage means, and drives and controls the clutch driving means in accordance with the determined degree of engagement. and control means.

[Operation] Therefore, while the vehicle is running, the vehicle speed deviation calculation means determines the target vehicle speed for the operation amount detected by the accelerator operation amount detection means based on the vehicle speed data in the vehicle speed data storage means, and detects the target vehicle speed and the vehicle speed detection means. The vehicle speed deviation from the actual vehicle speed is calculated.

Further, the vehicle speed deviation change calculating means calculates the change in the vehicle speed deviation before and after a predetermined elapsed time.

Then, in order to control the traveling speed to the speed instructed by the accelerator operating means, the clutch is adjusted to a predetermined half-connected state, and when the multiple connection determining means determines that the actual vehicle speed has asymptotically approached the target vehicle speed, the clutch control means In order to converge the actual vehicle speed to the target vehicle speed, connection amount data indicates the degree of clutch engagement with respect to the vehicle speed deviation calculated by the vehicle speed deviation calculation means and the vehicle speed deviation change calculated by the vehicle speed deviation change calculation means. The determination is made based on the connection amount data stored in the storage means, and the clutch driving means is drive-controlled in accordance with the determined degree of connection amount. As a result, the actual vehicle speed is converged to the target vehicle speed. At this time, since the connection amount data has an appropriate no-change area of the degree of connection with respect to the vehicle speed deviation and the change in vehicle speed deviation, in the process of converging the actual vehicle speed to the target vehicle speed, the connection amount data Even if a slight change occurs in the clutch, it is possible to maintain the clutch connection state appropriately without changing the connection state.

[Embodiment] Hereinafter, an embodiment in which the present invention is embodied in a forklift will be described in detail with reference to FIGS. 1 to 10.

FIG. 1 shows the drive system mechanism and electrical configuration of a forklift, in which the output of an engine 1 is transmitted to a transmission 3 via a dry single-plate clutch (hereinafter simply referred to as "clutch") 2.
Further, the driving drive wheels 5 are driven forward and backward through the differential gear mechanism 4 at a predetermined gear ratio. In this embodiment, the engine 1 is also used as a drive source for a hydraulic pump 6 that supplies hydraulic oil to a lift cylinder for raising and lowering a cargo handling fork (not shown) and a tilt cylinder for tilting a mast. ing.

The throttle opening of the engine 1 is adjusted by the drive of a throttle actuator unit made up of a step motor.
The rotation speed of the output shaft 1a of the engine 1 (engine rotation speed) is adjusted.

In addition, the clutch 2 for turning on and off the output from the engine 1 to the transmission 3 has a stroke amount of the rod 8a that expands and contracts based on the drive of a clutch drive actuator 8 as a clutch drive means. The connection state (connection position) is adjusted.

Further, the transmission 3 is switched between forward travel, neutral, and reverse travel based on the drive of its built-in forward/reverse switching actuator (as shown in the diagram), and is also switched between forward travel, neutral, and reverse travel based on the drive of the gear shift switching actuator (as shown in the diagram). It can be switched to 1st and 2nd speed. In this embodiment, forward/reverse switching and gear change of the transmission 3 are instructed by switching operations of a forward/reverse lever (not shown) provided at the driver's seat.

Next, an electrical configuration for driving and controlling each of the actuators 7, 8, etc. will be explained.

The engine rotation speed sensor 9 detects the rotation speed of the output shaft 1 a of the engine 1 and outputs the detection signal to the human output interface 10 .

The stroke detection sensor 11 is composed of a potentiometer, detects the stroke amount of the rod 8a of the clutch drive actuator 8, and sends the detection signal to the A/Il converter 12.
Convert to digital signal at input/output interface 1
Output to 0.

In addition, the input shaft rotation speed sensor 13 is connected to the input shaft 3a of the transmission 3.
The rotation speed (input shaft rotation speed) is detected and the detection signal is output to the input/output interface 10.

Further, a vehicle speed sensor 14 serving as vehicle speed detection means detects the rotational speed of the output shaft 3b of the transmission 3 relative to the vehicle speed, and outputs the detection signal to the input/output interface 10.

The accelerator sensor 15 as an accelerator operation amount detection means is composed of a potentiometer, and detects the operation amount ('Pi included amount) of an accelerator pedal 16 as an accelerator operation means installed in the driver's seat, and sends the detection signal to an A/D converter. At step 17, the signal is converted into a digital signal and output to the input/output interface 10.

A lever sensor 18 detects the amount of operation of a cargo handling lever 19 (in this embodiment, a lift lever for driving a lift cylinder) also provided at the driver's seat, and sends the detection signal to A.
The /D converter 20 converts the signal into a digital signal and outputs it to the input/output interface 10.

The microcomputer 21 includes a CPU (Central Processing Unit) 22 as a vehicle speed deviation calculation means, a vehicle speed deviation change calculation means, an overlap determination means, and a clutch control means, and a read-only CPU (Central Processing Unit) 22 as a vehicle speed data storage means and a connection amount data storage means. Program memory 23 consisting of memory (ROM)
and a work memo IJ24 consisting of a readable and rewritable memory (RAM) in which the results of arithmetic processing by the CPU 22 are temporarily stored. And C.P.
U22 operates based on a control program stored in program memory 23.

The program memory 23 stores in advance vehicle speed data corresponding to the amount of depression of the accelerator pedal 16, as shown in the map in FIG. Furthermore, the program memory 23 stores the target vehicle speed determined based on the map of the vehicle speed data and the vehicle speed sensor 14 as shown in the map in FIG.
The amount of engagement of the clutch 2 in each control cycle with respect to the vehicle speed deviation from the actual vehicle speed detected in is stored in advance as connection amount data, and as shown in the map in FIG. The periodic interval for finely moving the connection is stored in advance as interval data.

Furthermore, as shown in the map in FIG. 7, the program memory 23 stores the coupling degree (clutch control amount) of the clutch 2 with respect to the vehicle speed deviation and the change in vehicle speed deviation (difference in vehicle speed deviation) before and after each control period. It is stored in advance as connection amount data. This map is based on experiments in which the clutch control amount is determined in advance for the vehicle speed deviation and the difference between the vehicle speed deviations when the skilled driver arbitrarily operates the connection position of clutch 2 in order to converge the forklift to a predetermined running speed. Based on the results, this is a three-dimensional map created by creating rules for the clutch control amount for the vehicle speed deviation and the difference between the vehicle speed deviations in accordance with the characteristics of the clutch 2. That is, in this embodiment, the map shown in FIG. 7 is a map that rules out the relationship between the clutch control amount and the vehicle speed deviation and the difference between the vehicle speed deviations in order to execute fuzzy control of the vehicle speed. and,
In this map, an appropriate no-change region of the clutch control amount with respect to the vehicle speed deviation and the difference between the vehicle speed deviations is set in advance as a rule.

The CPU 22 detects each sensor 9, 11, 13, 14°15.1
8 detection signals are inputted via the input/output interface 10.

Then, the CPU 22 determines the current vehicle speed based on the detection signal from the vehicle speed sensor 14.

Further, the CPU 22 inputs the detection signal of the lever sensor 18 corresponding to the amount of operation of the cargo handling lever 19, and controls the input/output interface 10 and the throttle actuator drive circuit 25 in order to control the engine speed based on the amount of operation.
The throttle actuator 7 is driven and controlled via the throttle actuator 7.

Further, the CPU 22 determines whether to start operating the accelerator pedal 16 based on the detection signal of the accelerator sensor 15. When it is determined that the pedal 16 is not operated, the clutch 2 is held in a completely disengaged state, and the pedal 16 is held in a completely disengaged state.
6 has been operated, the clutch drive actuator 8 is driven and controlled via the input/output interface 10 and the clutch actuator drive circuit 26 in order to connect the clutch 2.

Further, the CPU 22 inputs the detection signal of the accelerator sensor 15 corresponding to the amount of operation of the accelerator pedal 16, and determines the target vehicle speed corresponding to the amount of operation based on the map shown in FIG. Then, the input/output interface 1
0 and a clutch actuator drive circuit 26 to drive and control the latch drive actuator 8.

At this time, the CPU'22 calculates the vehicle speed deviation between the determined target vehicle speed and the actual vehicle speed detected by the vehicle speed sensor 14, and also calculates the vehicle speed deviation for each control period (96 m5ec in this case).
Calculate the difference in vehicle speed deviation before and after.

Further, when the CPU 22 determines that the clutch 2 is in a predetermined half-engaged state and the actual vehicle speed detected by the vehicle speed sensor 14 has asymptotically approached the determined target vehicle speed, the CPU 22 performs a process to cause the actual vehicle speed to converge to the target vehicle speed. , the degree of engagement of the clutch 2 with respect to the vehicle speed deviation and the difference between the vehicle speed deviations is determined by a seventh
The decision is made based on the connection amount data shown in the map in the figure. Then, in order to adjust the half-engaged state of the clutch 2 according to the determined degree of engagement, the CPU 22 drives and controls the clutch drive actuator 8 via the input/output interface 10 and the clutch actuator drive circuit 26. That is, in this embodiment, the CPU 22 executes fuzzy control to cause the actual vehicle speed to converge to the target vehicle speed.

Along with this, the CPU 22 determines the engine speed at that time based on the detection signal from the engine speed sensor 9. At the same time, the CPU 22 detects the input shaft rotation speed sensor 13.
Based on the detection signal from the stroke detection sensor 11, the CPU 22 determines the input shaft rotation speed of the transmission 3 at that time.Furthermore, the CPU 22 calculates the stroke amount of the rod 8a of the clutch drive actuator 8 at that time, based on the detection signal from the stroke detection sensor 11. Determine the connection position of clutch 2. Then, the determined engine speed, input shaft speed, and stroke amount are input as feedback data for driving and controlling the clutch drive actuator 8.

Next, the operation of the forklift constructed as described above will be explained according to the flowcharts shown in FIGS. 9 and 10. In addition, in this embodiment, each flowchart is
22 shows the control operation of No. 22.

In this embodiment, when the cargo handling lever 19 is operated, the throttle actuator 7 is driven and controlled to increase the engine speed in order to obtain a desired engine output corresponding to the manipulated amount.

Further, the transmission torque of the clutch 2 is controlled in order to make the fluctuation in the traveling speed based on the control of the engine speed equal to the traveling speed relative to the amount of depression of the accelerator pedal 16.

First, speed control until the actual vehicle speed approaches the target vehicle speed will be explained according to the flowchart of FIG.

Now, in a state where cargo handling work is being performed by operating the cargo handling lever 19 as described above, in step 201 it is determined whether or not the accelerator pedal 16 is being depressed to instruct the forklift to travel. That is, it is determined whether or not there is a detection signal from the accelerator sensor 15.

If the accelerator pedal 16 is not depressed, it is assumed that the forklift is not instructed to run, and the process proceeds to step 202, in which the clutch drive actuator 8 is controlled to completely disengage the clutch 2, and processing is performed. end.

On the other hand, if the accelerator pedal 16 is depressed,
Proceeding to step 203, it is determined whether the clutch 2 is connected and in a static friction state. That is, based on the detection signals of the engine rotation speed sensor 9 and the input shaft rotation speed sensor 13, it is determined whether the engine rotation speed and the human power shaft rotation speed are substantially the same rotation speed.

If the clutch 2 is in a static friction state, the process moves to step 204, where the clutch 2 is moved to the learning point S1 where torque transmission from the engine 1 to the transmission 3 begins. The drive actuator 8 is driven and controlled, and the process ends. On the other hand, if the clutch 2 is not in a static friction state, the process moves to step 205;
A detection signal from the accelerator sensor 15 corresponding to the amount of depression of the accelerator pedal 16 is input, and a target vehicle speed corresponding to the amount of depression is determined based on vehicle speed data shown as a map in FIG.

Then, the process moves to step 206, where the actual vehicle speed is calculated based on the detection signal of the vehicle speed sensor 14, and further step 20
7, the vehicle speed deviation between the target vehicle speed and the actual vehicle speed is calculated.

Subsequently, the process moves to step 208, and it is determined whether the vehicle speed deviation is larger than necessary. That is, it is determined whether the vehicle speed deviation is within the first control region shown in FIG.

If the vehicle speed deviation is larger than necessary, the process moves to step 209, and based on the detection signals of the engine rotation speed sensor 9 and the input shaft rotation speed sensor 13, the engine rotation speed and the human power shaft rotation speed at that time are determined. , a torque transmission point S2 and a learning point s1 where the engagement position of the clutch 2 is on the disengaged side from the torque transmission point s2 shown in FIG. 3 based on both rotational speeds.
Determine whether or not there is a difference between the two. That is, it is determined whether the clutch 2 is in the connected position where the engine speed slightly exceeds the input shaft speed.

If the engagement position of the clutch 2 is not on the disengaged side of the torque transmission point S2, that is, if it is on the engagement side of the torque transmission point S2, the process moves to step 210, and this time the engagement position of the clutch 2 is the third one. Torque transmission point S2 and static friction transition point s3, which are on the cutting side of static friction transition point S3 shown in the figure.
Determine whether or not there is a difference between the two. That is, as shown in FIG. 3, it is determined whether the clutch 2 is at an intermediate position between the fully connected point S4, where the clutch 2 is fully connected, and the learning point Sl, which is a position where static friction is likely to occur. do.

If the connected position of the clutch 2 is not on the disengaged side of the static friction transition point S3, that is, if it is on the connected side of the static friction transition point S3, the process moves to step 211 to set the drive amount of the clutch 2 to zero. At that point, the drive of the clutch drive actuator 8 is stopped. Furthermore, the process moves to step 212, and the target engagement position of the clutch 2 is set at the static friction transition point S3.

Subsequently, the process moves to step 213, and it is again determined whether the engaged position of the clutch 2 is on the disengaged side of the static friction transition point s3. That is, as shown in FIG. 3, it is determined whether or not the area is above the level of the static friction transition point s3.

If the engagement position of the clutch 2 is not on the disengaged side than the static friction transition point S3, the process moves to step 214, and the clutch drive actuator 8 is activated to set the target engagement position of the clutch 2 to the static friction transition point S3. Drive control and end the process. On the other hand, in step 213, if the engaged position of the clutch 2 is on the disengaged side of the static friction transition point $3, the process ends.

Also, in step 208, if the vehicle speed deviation is larger than necessary and there is no vehicle speed deviation, that is, if the vehicle speed deviation is determined by the second control shown in FIG.
If it is in the a region, the process moves to step 215, and another vehicle speed control process to converge the vehicle speed to the target vehicle speed, which will be described later, is executed to change the engagement position of the clutch 2 to the static friction transition point S3.
After performing control so as to approach , the process jumps to step 213, executes the processing operations of steps 213 and 214, and ends the process.

Furthermore, in step 209, if the engagement position of the clutch 2 is on the disengaged side of the torque transmission point s2, then the process moves to step 216. In step 216, when the vehicle speed deviation between the target vehicle speed and the actual vehicle speed is large, the connection speed of the clutch 2 is increased so that the target vehicle speed is reached early, or as the vehicle speed deviation becomes smaller, the connection speed of the clutch 2 is increased. In order to slow down the vehicle speed and gradually approach the target vehicle speed, the amount of engagement of the clutch 2 is periodically controlled. That is, based on the connection amount data shown in the map in FIG. 4, the connection amount of the clutch 2, that is, the connection speed of the clutch 2 is controlled for each control period (95 m5ec in this embodiment) for vehicle speed deviation, and then step 213 Hejjump step 2
13. Executes the processing operation of 214 and ends the processing.

Further, in step 210, if the engaged position of the clutch 2 is on the disengaged side of the static friction transition point S3, the process moves to step 217. In step 217, the number of times the clutch 2 is connected is controlled in consideration of the fact that the transmission torque in the clutch 2 increases. That is, based on the interval data shown in the map in FIG. 5, the clutch 2 is driven by the minimum engagement amount in the first to fourth control cycles at the periodic intervals in which the clutch 2 is driven by the minimum engagement amount in response to the vehicle speed deviation at that time. In other words, as shown in Fig. 5, if the vehicle speed deviation is large, clutch 2 is driven by the minimum amount of engagement in each control cycle, and if the vehicle speed deviation is small, the clutch 2 is driven by the minimum engagement amount in each control cycle. 2 is driven by the minimum connection amount.

This clutch is used to deal with the fact that if the clutch 2 is stopped at the torque transmission point S2, the transmitted torque at the torque transmission point S2 will not be constant, and the vehicle speed may not increase. This is the second control.

After that, step 213 hedge jump, step 213
, 214 are executed, and the process ends.

As described above, in this embodiment, in the speed control until the vehicle speed asymptotically approaches the target vehicle speed, the clutch 2
The connection position is from learning point 81 to
It is adjusted in a semi-connected state within the area of the static friction transition point S3, and it is possible to asymptotically approach a desired traveling speed according to the amount of depression of the accelerator pedal 16, that is, a desired vehicle speed. Moreover, since the amount of engagement of the clutch 2 is periodically controlled according to the engagement position of the clutch 2 in the region from the learning point 81 to the static friction transition point S3, and the number of engagements of the clutch 2 is controlled, the curve shown in FIG. As shown in , it is possible to gradually move the clutch 2 toward the engagement side, and in the process of increasing the vehicle speed to the target vehicle speed, the engagement stiffness of the clutch 2 can be alleviated, and smooth vehicle speed control can be performed. .

Therefore, when the cargo handling speed is increased while maintaining the travel speed at a very low speed, that is, when the cargo handling lever 1 is
9, the output of the engine 1 is increased while the traveling speed is maintained at a very low speed. This can be done simply by operating the accelerator pedal 16. Therefore,
The inching pedal that is provided on a conventional forklift and used during cargo handling operations can be omitted, and the operability of cargo handling operations can be improved. That is, in this embodiment, the running speed of the forklift during cargo handling work can be easily controlled only by operating the cargo handling lever 19 and the accelerator pedal 16.

Next, after the actual vehicle speed asymptotically approaches the target vehicle speed, the speed control to further converge to the target vehicle speed, that is, the vehicle speed control in step 215 to be performed in the second control region shown in FIG. 8, is as shown in FIG. 1o. The explanation will be given according to the flowchart.

Now, in a state where the actual vehicle speed asymptotically approaches the target vehicle speed as described above, in step 301, it is determined whether or not the accelerator pedal 16 is depressed.

If the accelerator pedal 16 is not depressed, the process moves to step 302, where the clutch drive actuator 8 is controlled to completely disconnect the clutch 2, and the process ends. On the other hand, if the accelerator pedal 16 is depressed, the process moves to step 303, and the accelerator sensor 15 corresponds to the amount of depression of the accelerator pedal 16.
A detection signal is input, and a target vehicle speed corresponding to the amount of depression is determined based on the vehicle speed data shown in the map in FIG.

Next, the process moves to step 304, and it is determined whether the clutch 2 is connected and in a static friction state.

If the clutch 2 is in a static friction state, the process moves to step 305, and the target connection position of the clutch 2 is set to the torque transmission transition point (the torque transmission point S) as shown in FIG.
2) is set to S5, and the process is ended. On the other hand, if the clutch 2 is not in a static friction state, the process proceeds to step 306, where the actual vehicle speed is calculated based on the detection signal of the vehicle speed sensor 14, and the process further proceeds to step 307, where the vehicle speed deviation between the target vehicle speed and the actual vehicle speed is calculated. calculate.

Next, the process moves to step 308, and it is determined whether the vehicle speed deviation is larger than necessary. That is, it is determined whether the vehicle speed deviation is within the second control region shown in FIG.

If the vehicle speed deviation is larger than necessary, that is, if it is in the first control region in FIG. 8, step 309
Then, the vehicle speed control shown in the flowchart of FIG. 9 is executed. In other words, vehicle speed' control is executed to bring the actual vehicle speed asymptotically closer to the target vehicle speed.

On the other hand, if the vehicle speed deviation is not larger than necessary,
Proceeding to step 310, the difference in vehicle speed deviation before and after each control cycle is calculated.

Next, the process proceeds to step 311, in which the control amount of the clutch 2 for the vehicle speed deviation and the difference between the vehicle speed deviations is determined based on the map shown in FIG. Further, the process moves to step 312, and the clutch drive actuator 8 is drive-controlled in order to drive the clutch 2 by the control amount determined from the map in FIG. 7 from the current target connection position.

Subsequently, the process moves to step 313, and it is determined whether the engaged position of the clutch 2 is on the disengaged side with respect to the torque transmission transition point S5. If the engagement position of the clutch 2 is on the disengaged side of the torque transmission transition point S5, that is, in a region above the level of the torque transmission transition point S5 shown in FIG. 6, the process moves to step 314. , the target connection position of the clutch 2 is set at the torque transmission transition point S5. On the other hand, if the engagement position of the clutch 2 is not on the disengaged side than the torque transmission transition point s5, that is, if it is in the region below the level of the torque transmission transition point S5 shown in FIG. 6, the process moves to step 315. .

In step 315, it is determined whether the engagement position of the clutch 2 is closer to the engagement side than the static friction transition point S3.

If the engagement position of the clutch 2 is closer to the engagement side than the static friction transition point S3, that is, the static friction transition point S shown in FIG.
If it is in the region below level 3, the process moves to step 316, and the target engagement position of the clutch 2 is set at the static friction transition point S3.

On the other hand, if the engagement position of the clutch 2 is not closer to the engagement side than the static friction transition point s3, that is, the static friction transition point S3 shown in FIG.
If it is above the level, it is assumed that the vehicle speed control is going well and the process is terminated.

As described above, in this embodiment, in the speed control until the vehicle speed converges to the target vehicle speed, after the actual vehicle speed asymptotically approaches the target vehicle speed, the connection 2 position of the clutch 2 is changed to a torque level as shown by diagonal lines in FIG. Transmission transition point 85 to static friction transition point S3
The vehicle speed can be adjusted in a semi-connected state within the region of , and the vehicle speed can be converged to a desired vehicle speed according to the amount of depression of the accelerator pedal 16.

Moreover, in this embodiment, in the region from the torque transmission transition point 85 to the static friction transition point S3, the control amount of the clutch 2 is controlled by the clutch control amount with respect to the vehicle speed deviation and the difference between the vehicle speed deviations based on the map shown in FIG. At the same time, an appropriate no-change area for the clutch control amount with respect to the difference between the vehicle speed deviation and the vehicle speed deviation is set in this map, so in the process of converging the actual vehicle speed to the target vehicle speed, the difference between the vehicle speed deviation and the vehicle speed deviation Even if a slight change occurs in the target vehicle speed, the engagement position of the clutch 2 can be appropriately maintained near the torque transmission point S2, as shown by the solid line in FIG. 6, and the vehicle speed can be appropriately maintained at the target vehicle speed. It can be converged.

Therefore, in order to converge the actual vehicle speed to the target vehicle speed, the clutch drive actuator 8 is not driven frequently and the connection position of the clutch 2 is not frequently changed.
The driver's discomfort can be reduced. In other words, in order to converge the actual vehicle speed to the target vehicle speed, the engagement position of the clutch 2 can be controlled to provide a comfortable ride.

Note that this invention is not limited to the above embodiments,
The present invention can be implemented as follows by changing a part of the structure as appropriate without departing from the spirit of the invention.

(1) In the above embodiment, the relationship between the clutch control amount and the vehicle speed deviation and the difference between the vehicle speed deviations was specified as a rule in the three-dimensional map shown in FIG. 7, but the shape of this three-dimensional map may be changed as appropriate. You can make rules by doing so.

(2) In the embodiment described above, the accelerator pedal 16 was provided as the accelerator operating means, but another operating means such as an accelerator lever may be provided.

(3) In the embodiment described above, a cargo handling lever 19 corresponding to a lift lever is provided, but a cargo handling lever corresponding to a tilt lever or a tilt lever or other operating means may be provided.

(4) In the above embodiments, a forklift is used, but the invention may be applied to a cargo handling vehicle other than a forklift.

[Effects of the Invention] As detailed above, according to the present invention, the connection state of the clutch does not have to be changed frequently in order to converge to the traveling speed instructed by the operating means such as the accelerator pedal, and the riding comfort is improved. It exhibits an excellent effect in that the clutch can be kept in a half-connected state.

[Brief explanation of the drawing]

Figures 1 to 10 are drawings showing an embodiment embodying the present invention, in which Figure 1 shows the drive system mechanism and electrical configuration of a forklift, and Figure 2 shows the amount of depression of the accelerator pedal. 3 is a graph showing the transition of clutch stroke amount until it approaches the target vehicle speed, FIGS. 4 and 5 are maps showing clutch control with respect to vehicle speed deviation, and FIG. Graph showing the transition of clutch stroke amount until it converges to the target vehicle speed, No. 7
The figure is a map showing the clutch control amount with respect to the vehicle speed deviation and the difference between the vehicle speed deviations, Fig. 8 is a graph explaining the relationship between the vehicle speed deviation and the target vehicle speed, and Fig. 9 is a graph explaining the speed control until the target vehicle speed is approached asymptotically. Flowchart FIG. 10 is a flowchart illustrating speed control until convergence to the target vehicle speed. In the figure, 1 is an engine, 2 is a dry single plate clutch, 3 is a transmission, 8 is a clutch drive actuator as a clutch drive means, 14 is a vehicle speed sensor as a vehicle speed detection means,
15 is an accelerator sensor as an accelerator operation amount detection means; 16 is an accelerator pedal as an accelerator operation means; 2
Reference numeral 2 designates a CPU as vehicle speed deviation calculation means, vehicle speed deviation change calculation means, duplex determination means, and clutch control means. Reference numeral 23 represents a program memory as vehicle speed data storage means and connection amount data storage means. Patent applicant Toyota Industries Corporation Toyota Central Research Laboratory

Claims (1)

[Scope of Claims] 1. Clutch drive means for adjusting the connection state of the clutch that turns on and off the output from the engine to the transmission; Vehicle speed detection means for detecting the running speed of the vehicle; and For indicating the running speed. an accelerator operation amount detection means for detecting an operation amount of an operated accelerator operation means, and adjusts the clutch to a predetermined half-engaged state in order to control the traveling speed to a speed instructed by the accelerator operation means. The traveling speed control device includes: a vehicle speed data storage means that stores in advance a vehicle speed corresponding to an operation amount of the accelerator operation means as vehicle speed data; and a target vehicle speed corresponding to an operation amount detected by the accelerator operation amount detection means based on the vehicle speed data. vehicle speed deviation calculation means for calculating a vehicle speed deviation between the target vehicle speed and the actual vehicle speed detected by the vehicle speed detection means; and a vehicle speed deviation change calculation means for calculating the change in the vehicle speed deviation before and after a predetermined elapsed time. means, data for instructing the degree of engagement of the clutch with respect to the vehicle speed deviation and the change in the vehicle speed deviation, the data indicating an appropriate no-change area of the degree of engagement with respect to the vehicle speed deviation and the change in the vehicle speed deviation; a connection amount data storage means for storing in advance connection amount data as connection amount data; a vehicle speed determination means for determining whether or not the actual vehicle speed has asymptotically approached the target vehicle speed; When the vehicle speed determining means determines that the actual vehicle speed has asymptotically approached the target vehicle speed, in order to converge the actual vehicle speed to the target vehicle speed, the vehicle speed deviation calculated by the vehicle speed deviation calculating means and the vehicle speed are Determining the degree of engagement of the clutch with respect to the vehicle speed deviation change calculated by the deviation change calculation means based on the connection amount data stored in the connection amount data storage means, and according to the determined degree of connection. Clutch control means for driving and controlling the clutch drive means. A traveling speed control device for a vehicle.