JPH03168418A - Vehicle speed control device for cargo handling vehicle - Google Patents

Abstract

PURPOSE:To control vehicle speed following to a driver's likes at settling the actual vehicle speed on a target vehicle speed by deciding the connecting depth from connection data according to a selected setting mode, and adjusting the connecting condition of a clutch based on the decision. CONSTITUTION:A clutch control means 21 adjusts the output of an engine 1 through a throttle actuator driving circuit 25, so as to settle the actual vehicle speed detected with a vehicle speed sensor 14 on a target vehicle speed set from signals of an acceleration sensor 15 and a lever sensor 18. Simultaneously, the connecting depth of a clutch 2 is obtained from connection data of a program memory 23 according to the setting mode selected with a selection switch 29, and the connecting condition of the clutch 2 is adjusted based on the depth through a driving circuit 26 and a clutch actuator 8. Thus, a take-off of a vehicle accompanied with a cargo handling operation, a driver can optionally select and set a vehicle speed control mode according to the actual cargo handling operation, finely adjust acceleration by making the clutch in half clutch condition, and control the vehicle speed following to his likes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vehicle speed control device applied to a cargo handling vehicle such as a forklift.

[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 driving wheels are driven via 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 by adjusting the throttle opening based on the amount of operation of the operating means such as the cargo handling lever, and the vehicle speed is controlled based on the control of the engine speed. In order to adjust the fluctuation to a target vehicle speed relative to the amount of depression of the accelerator pedal, a speed control device for cargo handling operations has been proposed that is configured to be controlled by clutch transmission torque or braking force (for example, Japanese Patent Laid-Open No. 61-238535 Public bulletin).

According to this speed control device, the vehicle speed during cargo handling operations can be arbitrarily controlled by operating the cargo handling lever 1 and the accelerator pedal. It was possible to eliminate the inching pedal used for cargo handling operations, thereby improving the operability of cargo handling operations.

[Problem to be Solved by the Invention 1] However, in the conventional speed control device, the method of clutch control is unique in order to converge the actual vehicle speed to the target vehicle speed determined from the amount of accelerator depression when the vehicle starts due to cargo handling operation. Therefore, it was not possible to arbitrarily select and set vehicle speed control according to the content of cargo handling work according to the driver's personality and requests. For example, it has not been possible to arbitrarily select and perform vehicle speed control that has a different feel depending on the case, such as when it is desired to carry out cargo handling work carefully or when it is desired to carry out cargo handling work quickly.

Furthermore, the "automatic clutch control device" disclosed in Japanese Patent Application Laid-Open No. 60-12434 and the "automatic clutch control device" disclosed in Japanese Patent Application Laid-Open No. 61-102340 are capable of controlling slow or rapid starts. It has been proposed that a switch is provided to arbitrarily select and operate a clutch control mode for performing the following. However, in both of the above technologies,
The clutch connection speed was simply changed by operating a changeover switch, and no particular consideration was given to vehicle speed control accompanying cargo handling operations. That is, no consideration was given to controlling the vehicle speed without adjusting the clutch to a partially engaged state, and no consideration was given to adjusting the acceleration, which could have a subtle effect on the feeling of vehicle speed control in the partially engaged state. It wasn't.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to enable the driver to arbitrarily select and set a vehicle speed control mode depending on the content of the cargo handling operation when the vehicle is started for cargo handling operation. To provide a vehicle speed control device for a cargo handling vehicle which is capable of changing the acceleration while keeping the clutch in a half-connected state.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an engine that serves as both a drive source for traveling and a drive source for cargo handling;
Clutch driving means for adjusting the connection state of the clutch that turns on and off the output from the engine to the transmission, accelerator operation amount detection means for detecting the operation amount of the accelerator operation means operated to indicate the vehicle speed, and accelerator operation amount detection means A vehicle speed data storage means that stores in advance a target vehicle speed for the operation amount of the accelerator as vehicle speed data, and a vehicle speed detection means for detecting the vehicle speed, and the target vehicle speed for the operation amount detected by the accelerator operation amount detection means is determined based on the vehicle speed data. The clutch is set in a predetermined half-engagement state via the clutch drive means so that the actual vehicle speed detected by the vehicle speed detection means converges to the target vehicle speed. In a vehicle speed control device for a cargo handling vehicle that controls the vehicle speed by adjusting the vehicle speed to a continuous state, the mode selection means is operated to arbitrarily select a plurality of predetermined setting modes to control the vehicle speed with different feelings. , a connection data storage means that stores in advance different connection depths in a partially engaged state of the clutch as connection data according to the setting mode selected by operating the mode selection means, and convergence of the actual vehicle speed to the target vehicle speed. In order to determine the connection depth from the connection data according to the setting mode selected by operating the mode selection means, and adjust the connection state of the clutch based on the determined connection depth, the clutch and drive means and a clutch control means for controlling the drive of the clutch.

[Operation] According to the above configuration, one of a plurality of predetermined setting modes is arbitrarily selected by operating the mode selection means to perform vehicle speed control with a different feeling. When the accelerator operation means is operated when the vehicle starts, the target vehicle speed for the operation amount detected by the accelerator operation amount detection means is determined based on the vehicle speed data, and the actual vehicle speed detected by the vehicle speed detection means is determined based on the vehicle speed data. Until the vehicle speed converges to the target vehicle speed, vehicle speed control is performed by adjusting the clutch to a predetermined half-connected state via the clutch drive means. At this time, when converging the actual vehicle speed to the target vehicle speed, the clutch control means selects the clutch from the connection data pre-stored in the connection data storage means in accordance with the setting mode selected by operating the mode selection means. One of the different engagement depths in the half-engaged state is determined, and the clutch drive means is drive-controlled to adjust the engagement state of the clutch based on the determined engagement depth.

Therefore, by operating the mode selection means according to the content of the cargo handling work, the driver can arbitrarily set the vehicle speed control at the time of starting and perform it with a different feeling. In addition, since the clutch engagement depth is adjusted to control the vehicle speed, the acceleration when starting in a half-engaged state is set according to the setting mode selection, and varies from a gentle feeling to a sudden feeling. Subtle differences are given to the feel of vehicle speed control.

[Example] Hereinafter, an example in which the present invention is embodied in a forklift will be described in detail based on FIGS. 1 to 12.

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 also serves as a drive source for a cargo handling 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. It is used. The hydraulic oil from the hydraulic pump 6 is then distributed to a cargo handling hydraulic circuit 28 that includes a control valve 27 for supplying the lift cylinder and tilt cylinder. In this embodiment, the control valve 27 is drivably connected to a cargo handling lever I9 (in this embodiment, a lift lever for driving a lift cylinder) provided on the driver's seat, and is opened and closed in conjunction with the operation of the cargo handling lever 19. It is something that will be done.

The throttle opening of the engine 1 is adjusted by driving a throttle actuator 7 consisting of a step motor.
The rotation speed of the output shaft 1a of the engine I (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 engagement state, ie the engagement position (clutch stroke), is adjusted.

Furthermore, the transmission 3 is switched to forward travel, neutral, and reverse travel based on the drive of its built-in forward/reverse switching actuator (not shown), and is switched to l/l based on the drive of the gear change switching actuator (not shown). It can be switched to 1st or 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 input/output interface 10 .

The stroke detection sensor 1l is composed of a potentiometer, detects the stroke amount of the rod 8a of the clutch drive actuator 8, converts the detection signal into a digital signal by the A/D converter 12, and outputs the signal to the input/output interface 10.
Output to.

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 IO.

Further, a vehicle speed sensor l4 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 l5, which serves as an accelerator operation amount detection means, is composed of a potentiometer, and the accelerator sensor l5, which serves as an accelerator operation amount detection means, is configured to detect the operation amount (depression amount) of an accelerator pedal l6, which serves as an accelerator operation means provided in the driver's seat.
AC is detected, and the detection signal is converted into a digital signal by the A/D converter 17 and output to the input/output interface IO.

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

A mode selection switch 29 serving as a mode selection means performs vehicle speed control with different feelings in order to converge the actual vehicle speed detected by the vehicle speed sensor l4 to a target vehicle speed corresponding to the depression amount AC of the accelerator pedal l6. Be《
, is operated to arbitrarily select a plurality of predetermined setting modes, and outputs the setting signal to the input/output interface IO. Mode selection switch 2 of this embodiment
9. There is a "soft mode" where the feeling of vehicle speed control is gentle and slow, "hard mode" where the feeling of vehicle speed control is rapid, "soft mode" and "no x-mode" where the feeling of vehicle speed control is It is possible to select and set the "normal mode" which has a feeling between the two.

Microcomputer 2l constituting clutch control means
is a CPU (Central Processing Unit) 22, a program memory 23 consisting of a read-only memory (ROM) as a vehicle speed data storage means and a connection data storage means, and a readout memory 23 in which the arithmetic processing results of the CPU 22 are temporarily stored. It is composed of a working memory 24 consisting of a rewritable memory (RAM). And CPU2
2 operates based on a control program stored in program memory 23.

As shown in the map in FIG. 2, the program memory 23 stores in advance the throttle opening relative to the operation amount LC of the cargo handling lever l9 as first opening data.
As shown in the map in FIG. 3, the throttle opening relative to the depression amount AC of the accelerator pedal 16 is stored in advance as second opening data. Further, the program memory 23 stores in advance a target vehicle speed VO as vehicle speed data with respect to the depression ffiAc of the accelerator pedal 16, as shown in a map in FIG.

Furthermore, as shown in FIG. 5, the program memory 23 is used for control when both the accelerator pedal l6 and the cargo handling lever 19 are operated to start cargo handling, and the actual vehicle speed VL is recorded from the time the vehicle starts. Control areas A and B perform various controls to converge to the target vehicle speed VO. A map that classifies C is stored in advance, and as shown in FIG. 6, a map that defines the clutch stroke range with respect to the target vehicle speed VO in the control region C is also stored in advance.

Here, in the control region A shown in FIG. 5, in the initial stage from when the vehicle starts to when the actual vehicle speed VL converges to the target vehicle speed VO, the clutch is brought to a position where the clutch transmission torque necessary for starting the vehicle is obtained. 2 shows a region in which the clutch drive actuator 8 is drive-controlled so as to moderately suppress the connection speed of the clutch 2 after the clutch 2 is connected. Control area B of the same map is determined by calculating the deviation (vehicle speed deviation) VD of the actual vehicle speed VL from the target vehicle speed O in the middle stage following the initial stage, and adjusting the clutch 2 so that the vehicle speed deviation VD becomes small. This represents a feedback control area for driving and controlling the clutch drive actuator 8 in order to adjust the amount of connection.

Furthermore, the control region C of the same map is defined as a clutch stroke range (clutch stroke range) defined in advance relative to the target vehicle speed VO, as shown in the map in FIG. within the range),
This represents a feedback control area in which the clutch drive actuator 8 is drive-controlled by regulating the amount of engagement of the clutch 2 so that the vehicle speed deviation VD becomes small.

In the map shown in Fig. 5, the upper limit of the control region A is set to be constant regardless of the magnitude of the target vehicle speed VO except in the slow speed region, and the upper limit of the control region A is set to be constant regardless of the magnitude of the target vehicle speed VO except in the slow speed region. Correspondingly, the region upper limit is set to increase in proportion to the magnitude of the target vehicle speed VO. Also, the 6th
The map shown in the figure is set so that as the target vehicle speed VO decreases, the clutch stroke approaches the disengagement upper limit, that is, the engagement of the clutch 2 becomes shallower.

In addition, as shown in FIG. 7, the program memo 23 contains "
Soft mode J, "Normal mode", "Hard mode"
Connection data defining the connection depth of the clutch 2 in the half-connected state, that is, the depth of the clutch stroke, is stored in advance in accordance with each setting mode. This connection data is
Regarding the clutch stroke in the half-connected state of the clutch 2, from the learning point as the clutch stroke where torque transmission from the engine 1 to the transmission 3 begins to the complete contact point as the clutch stroke where the clutch 2 is fully connected. It is established. That is, a torque transmission transition point Sa corresponding to the control start point of the control area A;
The torque transmission point Sb1 corresponds to the switching point from the control in control area A to the control in control area B, and also corresponds to the upper limit of the depth of the clutch stroke in control area B, and is approximately the same as the complete contact point and the learning point. A static friction transition point Sc, which is an intermediate position and is a clutch stroke at which the clutch 2 is likely to enter a static friction state, is determined for each setting mode.

Furthermore, as shown in FIG. 8, the program memory 23 stores in advance the clutch control amount AD for the vehicle speed deviation VD, that is, the clutch engagement amount for each control period (96 ms in this case) as engagement amount data for each setting mode. has been done.

In addition, as shown in the map in FIG. 9, the program memory 23 stores clutch information as the degree of engagement of the clutch 2 with respect to the vehicle speed deviation VD and the vehicle speed deviation change (difference in vehicle speed deviation) ΔVD before and after each control period. The control amount AD is stored in advance as data for the "soft mode". Similarly, the program memory 23 stores in advance the clutch control MAD for the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations as data for the "normal mode". Furthermore, as shown in the map in FIG. 11, the program memory 23 stores in advance the clutch control amount AD for the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations as data for the "hard mode".

Each of the maps in Figures 9 to It shows the clutch control MAD for the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations when a skilled driver arbitrarily operates the clutch stroke in order to cause the forklift to converge to a predetermined target vehicle speed vO. The vehicle speed deviation V is determined in advance by an experiment and based on the experimental results
Clutch control ff for D and vehicle speed deviation difference ΔVD
This is a three-dimensional map created by creating rules based on iAD according to the characteristics of clutch 2. That is, in this example,
Each of the maps shown in FIGS. 9 to 11 is a map in which the relationship between the clutch control ffiAD and the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations is defined as a rule in order to execute fuzzy control of the vehicle speed. In these maps, appropriate no-change regions of the clutch control amount AD with respect to the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations are set in advance as rules.

The CPU 2 2 has each sensor 9, 11, 13, 14, 15 .
18 detection signals are inputted via the input/output interface 10, and a setting signal from the mode selection switch 29 is inputted.

Based on the detection signal from the engine rotation speed sensor 9, the CPU 22 determines the engine rotation speed relative to the engine output at that time. Further, the CPU 22 determines the current input shaft rotation speed transmitted to the transmission 3 via the clutch 2 based on the detection signal of the input shaft rotation speed sensor 13.

Furthermore, the CPU 22 determines the current actual vehicle speed VL based on the detection signal of the vehicle speed sensor l=1. Also, C.P.
U22 determines the stroke amount of the rod 8a of the clutch drive actuator 8, ie, the clutch stroke amount, based on the detection signal from the stroke detection sensor l1. Then, the CPU 22 inputs the determined engine rotational speed, input shaft rotational speed, actual vehicle speed VL, and stroke amount as feedback data for controlling the drive of each actuator 7, 8, etc.

Further, the CPU 22 determines that the set mode is "soft mode" based on the setting signal from the mode selection switch 29.
, "normal mode", or "hard mode".

Further, the CPU 22 determines based on the detection signals of the accelerator sensor 15 and the lever sensor 18 whether the cargo handling operation is in which only the cargo handling lever 19 is operated, the normal driving in which only the accelerator pedal l6 is operated, or whether the accelerator pedal 16 and the cargo handling lever 19 are both being operated, whether the running has been switched from normal running to cargo handling running, or whether the running has been switched from cargo handling running to normal running.

When the CPU 22 determines that the cargo handling operation is one in which only the cargo handling lever 19 is operated, the CPU 22 inputs the detection signal of the lever sensor 18 corresponding to the operating amount LC of the cargo handling lever l9, and The target opening degree is determined based on the map shown in FIG. Moreover, the CPU 22 is
In order to obtain the engine output accompanying the cargo handling operation, the throttle actuator 7 is drive-controlled via the input/output interface 10 and the throttle actuator drive circuit 25 based on the determined target opening degree.

Furthermore, the CPU 2 2 determines whether to start operating the accelerator pedal 16 based on the detection signal of the accelerator sensor 15, and if it determines that the pedal 16 is not operated, it holds the clutch 2 in a completely disengaged state. For this purpose, the clutch drive actuator 8 is drive-controlled via the input/output interface 1o and the clutch actuator drive circuit 26.

On the other hand, if the CPU 2 2 determines that it is normal driving in which only the accelerator pedal 6 is being operated, the CPU 2 2 connects the input/output interface 1o and the clutch actuator drive circuit 2G to bring the clutch 2 into a substantially fully connected state. The clutch driving actuator 8 is driven and controlled through the clutch driving actuator 8. At this time, the CPU 22 sets the throttle opening degree, that is, the target opening degree, to the third depression amount AC of the accelerator pedal l6.
Determine based on the map shown in the figure. Then, based on the determined target opening degree, the crowd flow interface 10
and drives and controls the throttle actuator 7 via the throttle actuator drive circuit 25.

In addition, when the CPU 22 determines that the accelerator pedal I6 and the cargo handling lever I9 are both being operated during cargo handling operation, the cargo handling lever I9 and the accelerator pedal I6 are operated in order to make the vehicle travel while carrying out cargo handling work. If both are operated, the target opening degree determined based on the operation amount LC of the cargo handling lever 19 and the target opening degree determined based on the depression amount AC of the accelerator pedal 1G are compared, and the target opening degree is determined. The throttle opening is controlled with priority given to the larger one. At the same time, the CPU 22 inputs the detection signal of the accelerator sensor I5 corresponding to the depression amount AC of the accelerator pedal l6, and sets the target vehicle speed VO corresponding to the depression amount AC to the fourth
Determine based on the map shown in the figure. Then, the clutch stroke is adjusted to a half-engaged state in accordance with each setting mode selected by the mode selection switch 29 so that the actual vehicle speed VL detected by the vehicle speed sensor l4 converges to the determined target vehicle speed VO. 0 and clutch actuator drive circuit 2
The clutch drive actuator 8 is driven and controlled via the clutch drive actuator 6 .

Next, in the forklift configured as described above, vehicle speed control at the time of starting cargo handling when both the accelerator pedal 16 and the cargo handling R/<-' 19 are operated will be explained according to the flowchart of FIG.

Note that this flowchart shows the control operation of the CPU 22.

When starting the vehicle, first, in step 101, a target vehicle speed VO for the depression and fflAc detected by the accelerator sensor 15 is determined based on the map shown in FIG. Here, for convenience, the target vehicle speed VO determined for the depression amount AC of the accelerator pedal 16 is assumed to be a value VIJ.

Next, in step 102, the actual vehicle speed VL detected by the vehicle speed sensor 14 is input.

Then, in step 103, it is determined whether or not the actual vehicle speed VL is within the control area A shown in the map of FIG. 5 with respect to the value VIJ of the target vehicle speed VO. At the initial stage of
Determine whether it is smaller than .

Here, if the actual vehicle speed VL is smaller than the value VABJ, control in the control area A is executed in steps 104 to 108.

That is, in step 104, the mode selection switch 2
Based on the setting signal from 9, it is determined whether the setting mode is "soft mode", "normal mode", or "hard mode".

Then, in step 105, from the map shown in FIG. A torque transmission point sb corresponding to the depth is determined according to the determined setting motor. In other words, as shown in Fig. 7, at the torque transmission transition point Sa, the clutch stroke is a soft mode point (
solid line arrow), a normal mode point tangential to it (dashed line arrow), or a hard mode point further tangential to it (dashed line arrow).
(two-dot chain arrow) and torque transmission point sb
Regarding, whether it is a soft mode point on the contact side of the torque transmission transition point Sa and closer to the learning point, a normal mode point on the contact side than that, or a hard mode point on the contact side further than that. decide.

These points Sa and Sb predetermine the depth of the clutch stroke within the control area A, and in the control of the control area A, the engagement speed of the clutch 2 is determined between these points Sa and Sb. will be controlled. or,
The torque transmission transition point Sa is related to the connection shock at the initial stage when the clutch 2 is connected when the vehicle starts, and in the soft mode, the shock is hardly felt even though the transmitted torque is relatively small, and in the hard mode In terms of modes, although the transmitted torque is relatively large, you will feel a light connection shock, and in terms of normal mode, it is set so that the shock is intermediate between the above two modes. Further, the difference in the engagement speed of the clutch 2 at the torque transmission point sb appears as a difference in the acceleration change rate. Furthermore, at a point in the control region A where the clutch stroke is deeper than the torque transmission point sb, the connection speed per control cycle is slow.
This difference in the depth of the torque transmission point sb also appears as a difference in the rate of change in acceleration.

Subsequently, in step 106, a vehicle speed deviation VD between the target vehicle speed VO and the actual vehicle speed VL is calculated. Then, in step 107, from the map shown in FIG. 8, the clutch control amount A for the calculated vehicle speed deviation VD is
Set D to the setting mode, that is, "soft mode",
Calculate according to "normal mode" and "hard mode". This clutch control amount AD corresponds to the amount of engagement of the clutch 2 to be driven in each control cycle of the CPU 22, and is set in advance so as to moderately suppress the engagement speed of the clutch 2 within the control area A. This is the value. Further, the difference in the magnitude of the clutch control ffiAD between the modes appears as a difference in the rate of change in acceleration, similar to the difference in the torque transmission point sb between the modes.

Then, in step 108, from the torque transmission transition point Sa determined according to the setting mode to the torque transmission point s
During period b, until the clutch transmission torque necessary for starting the vehicle is obtained, the clutch drive actuator 8 is activated in order to drive the clutch 2 at a convenient engagement speed according to the determined clutch control MAD. The drive is controlled and the subsequent processing is temporarily terminated.

After that, as a result of the processing in step lot-108, when the actual vehicle speed VL becomes equal to or higher than the "value VAB" in step 103, the process moves from step 103 to step 109, and the actual vehicle speed vehicle speed VL
It is determined whether or not it is in the control area B shown in the map in FIG. That is, in this case, in the middle stage following the initial stage, it is determined whether the actual vehicle speed VL is smaller than the value V BCJ at the boundary between the control area B and the control area C.

If the actual vehicle speed VL is smaller than the value V BCJ, control in the control region B is executed in steps 110 to 115.

That is, in step 110, mode selection switch 2
The setting mode is determined based on the setting signal from 9. Then, in step 111, the static friction transition point Sc in the clutch stroke is determined from the map shown in FIG. 7 in accordance with the determined setting mode. In other words,
As shown in Fig. 7, the static friction transition point Sc approximately halfway between the learning point and the complete contact point is either the soft mode point on the most disengaged side of the clutch stroke, the normal mode point on the more contact side, or Determine the hard mode point on the tangent side. This static friction transition point Sc predetermines the upper limit of the clutch stroke depth within the range of control region B, and in the control of control region B, the clutch 2 is connected until this static friction transition point Sc. The speed will be controlled. Further, the difference between the setting modes at the static friction transition point Sc, that is, the difference in the upper limit of the depth of the clutch stroke, appears as a difference in acceleration.

Next, in step 112, a vehicle speed deviation VD between the target vehicle speed V○ and the actual vehicle speed VL is calculated. Further, in step 113, a difference ΔVD in vehicle speed deviation before and after each control cycle is calculated.

That is, the difference between the vehicle speed deviation VD in the previous control cycle and the vehicle speed deviation VD in the current control cycle is calculated.

Next, in step 114, a map corresponding to the setting mode determined in step 110 is identified from among the maps shown in FIGS. 9 to 11, that is, a map corresponding to "soft mode,""normalmode," and "hard mode." A clutch control amount AD for the calculated vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations is determined from the specified map. Here, the clutch control ffi A. which is calculated from different maps for each setting mode. The difference in the upper limit of D appears as a difference in the rate of change in acceleration.

Then, in step 115, the engagement speed of the clutch 2 is set such that the vehicle speed deviation VD is small within the control region B in which the static friction transition point Sc determined according to the setting mode is the upper limit of the depth of the clutch stroke. In order to adjust the amount of connection for each control cycle, the clutch drive actuator 8 is feedback-controlled, and the subsequent processing is temporarily terminated.

After that, as a result of the processing in steps 101 to 103 and 109 to 115, in step 109 the actual vehicle speed VL is
If the value is greater than or equal to the value V BCJ, the actual vehicle speed V L
Assuming that the target vehicle speed VO is in the final stage where it converges to the value VIJ, control in the control region C is executed in steps 116 to 120.

That is, in step 116, the mode selection switch 2
The setting mode is determined based on the setting signal from 9. Next, in step 117, a vehicle speed deviation VD between the target vehicle speed VO and the actual vehicle speed VL is calculated. Furthermore, in step ll8, the difference ΔVD in vehicle speed deviation before and after each control cycle is calculated.

Next, in step 119, a map corresponding to the setting mode determined in step 116 is identified from among the maps shown in FIGS.
, "Normal mode" and "Hard mode", and determines the clutch control amount AD for the calculated vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations from the specified map.

Then, in step 120, as shown in the map in FIG. 6, within a predetermined clutch movable range relative to the target vehicle speed Vo, the vehicle speed deviation VD of the actual vehicle speed VL with respect to the value VIJ of the target vehicle speed VO is small. In order to drive the clutch 2 with the clutch control amount AD determined in step 119 so that
feedback control.

As described above, in this embodiment, the clutch 2 is slowly engaged in the initial stage until the actual vehicle speed VL converges to the target vehicle speed Vo when starting the vehicle for cargo handling, and the vehicle speed starts from zero. Starts smoothly. Further, in the middle stage following the initial stage, the amount of engagement of the clutch 2 is adjusted so that the deviation of the actual vehicle speed VL from the target vehicle speed V○ becomes small, so that the target vehicle speed VO is reached more quickly. Furthermore, at the final stage when the vehicle speed converges to the target vehicle speed VO, the amount of engagement of the clutch 2 is regulated based on a predetermined clutch movable range, and the movement of the clutch 2 is regulated around the target vehicle speed VO. The actual vehicle speed VL converges to the target vehicle speed VO, and the target vehicle speed V
O can be maintained stably.

In this embodiment, as described above, the actual vehicle speed VL
The vehicle speed is controlled in three stages: initial stage, middle stage, and final stage until convergence to the target vehicle speed VO, and the upper limit of the control region A performed in the initial stage is set to the target except for the slow speed range. It is set to be constant regardless of the magnitude of the vehicle speed VO. Therefore, the period during which the engagement speed of clutch 2 is suppressed before and after the engine torque necessary for starting can be obtained can be shortened, and as a result, the vehicle can quickly reach the target vehicle speed Vo from starting from zero vehicle speed. , drivability can be improved.

Further, in this embodiment, in the final stage when the actual vehicle speed VL converges to the target vehicle speed VO, the clutch movable range can be restricted to stably converge to the target vehicle speed V○, so that the target vehicle speed Vo Even if the actual vehicle speed VL is small, the movement of the clutch 2 can be restricted to stably converge the actual vehicle speed VL to the target vehicle speed VO, and the stable state can be maintained.

In this embodiment, the clutch stroke depths at the torque transmission transition point Sa, torque transmission point sb, and static friction transition point Sc in the control region A and control region B are set to "soft mode,""normal mode j," and "hard mode." Three slightly different points are determined in advance, and the driver can arbitrarily select and set each mode by operating the mode selection switch 29. In other words, by selecting this setting mode, the driver can arbitrarily select the feeling of vehicle speed control when the vehicle starts from among three types, ranging from a gentle feeling to a sudden feeling. In this way, the feeling of vehicle speed control during cargo handling can be adjusted more precisely and suitably according to the contents of the cargo handling work and the individuality and demands of the driver, and drivability can be improved. Furthermore, since the depth of the clutch stroke is adjusted according to each setting mode for vehicle speed control, the acceleration when starting in a half-engaged state will change depending on the setting mode, which may slightly affect the feeling of vehicle speed control. can make a huge difference.

Similarly, the clutch control amount AD in each control region A-C
Also, the driver selects "soft mode" from each map in FIGS. 8 to 11 by operating the mode selection switch 29.
Since the "normal mode" and "hard mode" can be changed subtly, the feeling of vehicle speed control can be made more finely suited to the content of cargo handling work.

Moreover, in control regions B and C, the clutch control amount AD is determined based on the three-dimensional maps shown in Figures 9 to 1l according to each setting mode, and the difference ΔVD between the vehicle speed deviation VD and the vehicle speed deviation
In addition, in the same three-dimensional map, the no-change area of the clutch control flAD with respect to the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations is set appropriately, so that the actual vehicle speed VL can be controlled by the clutch control HNAD. In the process of converging to the target vehicle speed VO, even if a slight change occurs in the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations, the clutch stroke is appropriately maintained within a predetermined upper limit range of clutch stroke depth. Therefore, the actual vehicle speed VL can be appropriately converged to the target vehicle speed VO. Therefore, in order to control the vehicle speed, the clutch drive actuator 8 is not driven frequently and the clutch stroke is not changed frequently, and the discomfort caused to the driver can be reduced, and the clutch 2 can have a comfortable ride.
can be controlled.

Therefore, when you want to carry out careful cargo handling work, by setting the mode selection switch 29 to "soft mode", you can start the vehicle quickly with a gentle and slow feeling with a small rate of change in acceleration. When you want to carry out cargo handling work, you can set the mode selection switch 29 to "hard mode" to start the vehicle with a rapid feeling with a relatively large rate of change in acceleration. "Normal mode"
By setting this, the vehicle can be started with a normal feeling in which the rate of change in acceleration is neither large nor small.

Note that this invention is not limited to the above embodiments,
A part of the structure can be changed as appropriate without departing from the spirit of the invention, and the invention can be implemented as follows.

(1) In the above embodiment, the torque transmission transition point Sa and the torque transmission point sb in each control of the control region A and the control region B
and “soft mode” for each point of static friction transition point Sc.
, ``Normal mode J'' and ``Hard mode'' have three slightly different points, but each of the points Sa,
Regarding points other than Sb and Sc, three slightly different points may be provided for each setting mode.

(2) In the above embodiment, all of the torque transmission transition point Sa, torque transmission point sb, and static friction transition point Sc are explained as follows.
There are three slightly different points for Soft Mode J, "Normal Mode" and "Hard Mode".
Each of the points Sa, Sb. Only one or two points of Sc may be provided with three slightly different points depending on each setting mode. (3) In the above embodiment, torque transmission in each control of control area A and control area B Transition point Sa, torque transmission point sb
and “soft mode” for each point of static friction transition point Sc.
, "Normal mode J" and "Hard mode" We have provided slightly different points depending on the three setting modes,
There may be two or four or more setting modes, each with slightly different points depending on the setting mode, and the selection may be made using a mode selection switch.

(4) In the above embodiment, in each control of the control area B and the control area C, the clutch control amount AD is determined for the vehicle speed deviation VD and the difference ΔVD between the vehicle speed deviations based on the three-dimensional maps shown in FIGS. 9 to 11. However, the clutch control itAD may be simply calculated based on a two-dimensional map in which the clutch control amount AD for the vehicle speed deviation VD is predetermined. (5) In the embodiment described above, the accelerator pedal l6 is used as the accelerator operation means. However, another operating means such as an accelerator lever may be provided.

(6) In the embodiment described above, a cargo handling lever l9 corresponding to a lift lever is provided, but a cargo handling lever corresponding to a tilt lever or a reach lever may be provided, or other operating means may be provided.

(7) 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, when the vehicle is started for cargo handling operation, the driver can arbitrarily select and set the vehicle speed control mode according to the content of the cargo handling operation. What's more, it has the unique effect of allowing the vehicle speed to be controlled in accordance with the driver's individuality and requests by subtly changing the acceleration while leaving the clutch in a partially engaged state.

[Brief explanation of the drawing]

Figures 1 to 12 are drawings showing embodiments of the present invention, in which Figure 1 shows the drive system mechanism and electrical configuration of the forklift, and Figure 2 shows the amount of operation of the cargo handling lever. 3 is a map showing the relationship between the throttle opening and the amount of accelerator pedal depression. FIG. 4 is a map showing the relationship between the target vehicle speed and the amount of accelerator pedal depression. is a map that divides the control region for converging the actual vehicle speed to the target vehicle speed from the time the vehicle starts, FIG. 6 is a map that defines the clutch stroke range for the target vehicle speed, and FIG. 7 is the torque transmission transition point, torque transmission 8 is a map showing the relationship between the clutch control amount and the vehicle speed deviation, and FIG. 9 is the difference between the vehicle speed deviation and the vehicle speed deviation in the soft mode. 10 is a map showing the relationship of the clutch control amount to the vehicle speed deviation in normal mode and the difference between the vehicle speed deviations. FIG. 11 is a map showing the relationship between the vehicle speed deviation and the difference between the vehicle speed deviations in the hard mode. A map showing the relationship between the clutch control amount and the
FIG. 12 is a flowchart illustrating vehicle speed control when starting cargo handling travel. In the figure, ■ is the engine, 2 is the clutch, 3 is the transmission, 8 is the clutch drive actuator as the clutch drive means, l4 is the vehicle speed sensor as the vehicle speed detection means, and l5 is the accelerator sensor as the accelerator operation amount detection means. , 16 is an accelerator pedal as an accelerator operation means, 2l is a microcomputer as a clutch control means, and 23 is a program memory as a vehicle speed data storage means and a connection data storage means. Figure 5 Figure 6 Figure 6 O Target vehicle speed (VO) Figure 8 U St series 1! Difference (VD) ○ Speed II difference (Km/h) ○ *Difference i (VD)

Claims (1)

[Scope of Claims] 1. An engine that serves as both a drive source for traveling and a drive source for cargo handling, a clutch drive means that adjusts the connection state of a clutch that turns on and off the output from the engine to a transmission, and a vehicle speed control system. an accelerator operation amount detection means for detecting an operation amount of an accelerator operation means operated to give an instruction; a vehicle speed data storage means for storing in advance a target vehicle speed as vehicle speed data for the operation amount of the accelerator operation means; a vehicle speed detection means for detecting, and determining a target vehicle speed for the operation amount detected by the accelerator operation amount detection means based on the vehicle speed data;
The vehicle speed of the cargo handling vehicle is controlled by adjusting the clutch to a predetermined half-connected state via the clutch drive means so that the actual vehicle speed detected by the vehicle speed detection means converges to the target vehicle speed. The control device includes: a mode selection means that is operated to arbitrarily select a plurality of predetermined setting modes to perform vehicle speed control with different feelings; Accordingly, connection data storage means stores in advance different connection depths in the half-engaged state of the clutch as connection data, and when converging the actual vehicle speed to the target vehicle speed, the mode selection means Clutch control means for determining a connection depth from the connection data according to the selected setting mode, and driving and controlling the clutch drive means to adjust the connection state of the clutch based on the determined connection depth; Vehicle speed control device for cargo handling vehicles equipped with