JP3536785B2 - Travel control device for industrial vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control device for an industrial vehicle such as a reach-type forklift truck which performs traveling control for preventing sudden acceleration and sudden start.

[0002]

2. Description of the Related Art For example, a reach-type forklift truck (hereinafter referred to as a reach-type forklift) has a pair of left and right reach legs extending forward of a vehicle body, and a mast device provided with a fork can move back and forth along the pair of reach legs. Is equipped with The left and right front wheels (driven wheels) are supported at the tip of the reach leg, and the rear wheels are drive steering wheels. The driver's seat provided at the rear of the vehicle body is of a standing type, and the operator gets on the vehicle while standing in the driver's seat.

When the forklift turns, the steered wheels are cut to a certain tire angle, and the steered wheels are driven in this state, whereby the vehicle turns so that the rear part of the vehicle body swings obliquely forward. Since a forklift is required to have a small turning performance, the steered wheels can be turned to a relatively large steering angle (for example, about 80 ° or more). At the time of turning, the driver's seat located at the rear of the vehicle body moves relatively greatly, so that the driver's body is easily swung sideways during turning of the vehicle.

[0004]

By the way, when the reach type forklift is started, even if the operation amount of the accelerator lever is the same, when the drive steered wheels are turned off and the steering angle is large, the vehicle is easy to start suddenly as compared with straight running. This is because, as the steering angle of the drive steering wheel increases, the traveling distance of the front wheel (driven wheel) during turning becomes smaller than the traveling distance of the driving steering wheel (rear wheel), and as the traveling distance of the front wheel decreases. This is because the starting resistance of the vehicle is reduced. Since the force for accelerating the vehicle body is obtained by subtracting the starting resistance from the driving force of the drive steered wheels, the vehicle body acceleration increases as the steering angle increases even with the same operation amount of the accelerator lever.

In a reach-type forklift, the steering wheel (steering wheel) can rotate more than two times, so that the steering angle of the driven wheels cannot be determined only by looking at the position of the steering wheel. Further, the driver's seat cannot see the steered wheels and cannot check the steering angle. Therefore, in the case of a reach type forklift, once it stops, the direction of the drive steered wheels is not known, and if the accelerator lever is tilted to the maximum with the intention of going straight despite the drive steered wheels being turned off, the vehicle will turn. However, there is a problem that, although not dangerous, the operator's body is pressed against the inner wall of the driver's seat or surprised. Also, not only when starting, but also when accelerating the accelerator lever during turning, or when performing switchback operation to move the accelerator lever to the opposite side to the direction of travel during turning, sudden acceleration against the operator's will Or sudden braking, a sudden acceleration could occur while the vehicle was turning.

[0006] As a prior art, a traveling control device (JP-A-2-299402) for reducing the driving torque of a traveling motor (electric motor) when a slip of a driven steering wheel is detected.
JP, JP-A-3-27701, JP-A-11-1
No. 78120). However, all of these prior arts reduce the driving torque at the time of detecting the slip of the driven steering wheel, but the driving torque of the traveling motor is not always limited when the steering angle is large. The problem was as well.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to suppress the acceleration of a vehicle when turning a vehicle and to reduce a force that a driver receives in a lateral direction when the vehicle turns. An object of the present invention is to provide a travel control device for an industrial vehicle, which can provide a travel control device for an industrial vehicle that can perform the above.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to claim 1 is directed to an industrial vehicle for controlling driving means for driving driving wheels of an industrial vehicle based on operation of operating means. In the travel control device, detecting means for obtaining a detection value for predicting or detecting turning of the vehicle, and when predicting or detecting turning of the vehicle based on the detection value of the detecting means, Control means for controlling the driving means so as to limit the maximum driving force of the driving wheel so as to limit acceleration , wherein the control means comprises a detecting means.
When the turning of the vehicle is predicted or detected based on the detected value of the step
In the case of the straight running,
The driving means should be controlled so as to be relatively small.
And the summary .

According to this configuration, when the turning of the vehicle is predicted or detected based on the detection value of the detecting means by the control means, the driving means is controlled, and the maximum driving force of the driving wheels is limited. Therefore, acceleration (including deceleration) during turning of the vehicle can be suppressed to a small value. For example, even when the operating means is largely operated at the time of starting with the intention of going straight without knowing that the steered wheels are in a turned state, sudden start of the vehicle against the driver's will is avoided. Also, the control means detects the detection value of the detection means.
When the turning of the vehicle is predicted or detected based on the
Is controlled, and the torque increase speed of the driving means is
It is limited to a very small amount.

[0010]

[0011]

[0012]

[0013]

According to a second aspect of the present invention, an industrial vehicle is driven.
Controls driving means for driving wheels based on operation of operating means
In a traveling control device for an industrial vehicle,
Detection means for obtaining a detection value for measurement or detection
Predicting the turning of the vehicle based on the detection value of the detection means,
Limits the acceleration of the vehicle when turning
Drive to limit the maximum drive force of the drive wheels
Control means for controlling the means , wherein the control means, when predicting or detecting the turning of the vehicle based on the detection value of the detection means, both the maximum output torque of the drive means and the torque increasing speed The gist of the present invention is to control the driving means so that the driving means is restricted to be smaller than that during traveling.

According to this configuration, the detection means is controlled by the control means.
When the turning of the vehicle is predicted or detected based on the detection value of the step,
The driving means is controlled and the maximum driving force of the driving wheels is limited
You. Therefore, the acceleration (including deceleration) when turning the vehicle
Can be kept small. For example, the steered wheels are turned off
The operation means is largely manipulated when starting
Even if you do, the vehicle will suddenly start against the driver's will
Be avoided. Further , when the turning of the vehicle is predicted or detected based on the detection value of the detecting means, the driving means is controlled by the control means, and both the maximum output torque and the torque increasing speed of the driving means are limited to be smaller than when traveling straight. You. For this reason, the acceleration at the time of turning the vehicle can be effectively suppressed to a small value.

[0016] The invention described in claim 3 is claim 1 or claim 3.
In the invention described in claim 2 , the detection means is a steering angle detection means for detecting a steering angle of a steering wheel of an industrial vehicle, and the control means detects a steering angle detected by the steering angle detection means. The gist of the present invention is to predict the turning of the vehicle based on this.

According to this structure, claim 1 or claim 2
In addition to the operation of the invention described in the above, the steering angle of the steered wheels of the industrial vehicle is detected by the steering angle detecting means. The control unit predicts the turning of the vehicle based on the steering angle detected by the steering angle detection unit. For this reason, the control of the driving means for limiting the maximum driving force of the driving wheels is started early. Therefore, the acceleration at the time of turning the vehicle can be suppressed without delay.

[0018] invention as set forth in claim 4, in the invention described in any one of claim 1 to 3, wherein the control means,
The gist of the present invention is to control the driving unit so as to limit the output value of the driving unit determined according to the operation amount of the operation unit to a small value.

According to this configuration, in addition to the effect of the invention according to any one of claims 1 to 3 , when the turning of the vehicle is predicted or detected, the driving means is controlled by the control means, and the operation is controlled. The output value of the driving means determined according to the operation amount of the means is limited to a small value. For this reason, at the time of turning of the vehicle, for example, the acceleration can be suppressed to an appropriate acceleration suitable for the operation amount of the operation means.

[0020]

[0021]

According to a fifth aspect of the present invention, there is provided the industrial vehicle according to any one of the first to fourth aspects, wherein one of the front wheel and the rear wheel is a drive steering wheel, and the front wheel and the rear wheel are The gist is that the driver's seat arranged near the drive steering wheel is a standing type.

According to this configuration, any one of claims 1 to 4
In addition to the effect of the invention described in any one of the above aspects, when turning , the industrial vehicle turns such that the drive steered wheels turn outward. For this reason, a driver standing in a standing driver's seat is likely to swing greatly to the side, but when the vehicle turns, the maximum driving force of the driving wheels is limited, and the acceleration during the vehicle turning is suppressed to a small degree. The lateral force applied to the driver in the driving posture is reduced and reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a travel control device for a reach type forklift truck will be described below with reference to FIGS.

As shown in FIGS. 2 and 3, a reach-type forklift truck (hereinafter, referred to as a reach-type forklift) 10 as an industrial vehicle is driven by left and right front wheels 1.
This is a three-wheeled vehicle provided with drive wheels 1 and 11 and drive steered wheels (rear wheels) 12 as drive wheels and steered wheels. The drive steering wheel 12 is located slightly to the left of the center of the vehicle width, and an auxiliary wheel (caster wheel) 13 is provided on the right side thereof at a predetermined distance.

The vehicle body 14 is provided with a pair of left and right reach legs 14A extending forward. Left and right front wheels 11, 1
Numerals 1 are respectively supported on the distal ends of the reach legs 14A. A mast device 15 is provided between the reach legs 14A so as to be able to perform a reach operation in the front-rear direction. The mast device 15 performs a reach operation by driving a reach cylinder 16 provided on the lower rear side of the vehicle body 14. The mast device 15 includes a mast 17, a lift cylinder 18, a fork 19, and the like. The mast 17 slides up and down by driving the lift cylinder 18 to expand and contract, so that the fork 19 moves up and down in conjunction with the mast 17.

On the rear left side of the vehicle body 14,
Is provided with a drive unit 20 for driving the. The drive unit 20 is provided with a driving means 21 as a driving means and an electric motor at an upper portion thereof.
The drive steering wheel 12 supported at the lower part of the drive unit 20 is driven by 1. In the present embodiment, an AC induction motor is used as the traveling motor 21.

On the rear right side of the vehicle body 14, an upright driver's seat 22 is provided. An operation panel 23 is provided in front of the driver's seat 22. The operation panel 23 is provided with an accelerator lever 24 and a cargo handling lever 25 as operation means.
A steering wheel 26 is provided on the left side of the driver's seat 22, and the steering wheel 12 is steered by operating the steering wheel 26.

As shown in FIG. 1, the drive unit 20
And the caster wheel 13 are supported by a suspension mechanism 27 so as to be displaceable upside down.
The suspension mechanism 27 is capable of driving the steering wheel 1 even if the weight at the rear of the vehicle changes due to a difference in the cargo handling state such as the presence or absence of a load.
The wheel weights of the drive steer wheels 12 and the caster wheels 13 are distributed so that the wheel weights required for No. 2 are secured.

The suspension mechanism 27 includes a drive unit support 28 for supporting the drive unit 20 so as to be vertically displaceable, and a caster arm 29 for supporting the caster wheel 13 so as to be vertically displaceable. The drive unit support 28 is fixed so as to be integrally rotatable with a first rotation shaft 30 rotatably supported on the vehicle body 14, and swings up and down in a plane orthogonal to the vehicle width direction (the left-right direction in FIG. 1). It is movably supported. The caster arm 29 is fixed to a second rotation shaft 31 rotatably supported by the vehicle body 14, and is supported so as to be able to swing up and down in a plane orthogonal to the vehicle width direction. The first rotation shaft 30 and the second rotation shaft 31 are engaged with a lever (not shown) fixed to the first rotation shaft 30 and a lever (not shown) fixed to the caster arm 29. Are operatively connected to rotate in opposite directions.

The traveling motor 21 is disposed on the upper surface of the drive unit support 28, and on the lower surface of the drive unit support 28, a gear box 32 for rotatably supporting the drive steering wheel 12 at a lower portion is rotatable within the surface. (Steerable). A steering gear 32A is provided at an upper portion of the gear box 32 so as to be integrally rotatable. The steering gear 32A is operatively connected to a steering shaft (not shown) of the steering wheel 26.

Drive unit support 28 and body 14
A suspension spring 35 for applying a preload that presses and biases the drive steering wheel 12 against the road surface is interposed between the drive steering wheel 12 and the caster wheel 13. An extra wheel weight is always added. A lock cylinder (hydraulic damper) 36 is provided between the drive unit support 28 and the vehicle body 14. Lock cylinder 36
The suspension mechanism 27 is locked when the lock cylinder 36 is locked by electromagnetically controlling the electromagnetic valve 37 mounted on the suspension valve 27.

As shown in FIG. 1, the cargo handling system hydraulic circuit includes an oil tank 40, a cargo handling motor 41, a hydraulic pump (a cargo handling pump) 42, a reach valve 43, and a lift valve 4
4, a tilt valve 45, the cylinders 16 and 18, the tilt cylinder 46, and the like. Specifically, each of the valves 43 to 45 is integrally incorporated as an oil control valve.

The cargo handling motor 41 drives a hydraulic pump 42 to supply hydraulic oil in an oil tank 40 to each of the valves 43, 44, 45 at a predetermined hydraulic pressure. Each of the valves 43 to 45 is manually driven by the operation of each of the cargo handling levers 25, and the operated cargo handling lever 2 of the cylinders 16, 18, 46 is operated.
The connection destination of the hydraulic path corresponding to 5 is connected to the cargo handling lever 2
Switching is performed between the supply pressure path from the hydraulic pump 42 and the discharge path to the oil tank 40 according to the operation direction of No. 5.

The electric control of the traveling system and the cargo handling system is shown in FIG.
Is performed by a controller 50 as a control means shown in FIG. The input side of the controller 50 includes an accelerator sensor 5
1. The traveling direction detection switches 52 and 53, the reach switch 54, the lift switch 55, the tilt switch 56, the drive wheel speed sensors 57 and 58, and the steering angle sensor 59 as the steering angle detecting means are electrically connected. The output side of the controller 50 is electrically connected to the traveling motor 21, the locking solenoid valve 37, and the cargo handling motor 41.

The accelerator sensor 51 includes an accelerator lever 2
The accelerator opening of 4, that is, the operation amount at the neutral position is “0”
And detects and outputs the accelerator opening Acc on the forward side and the reverse side.

The traveling direction detection switches 52 and 53 are both turned off when the accelerator lever 24 is at the neutral position. The switch 52 is turned on from off to output the forward signal SF only when the accelerator lever 24 is operated forward from the neutral position, and the switch 53 is operated when the accelerator lever 24 is operated backward from the neutral position. And the reverse signal SR is output.

Each of the switches 54 to 56 operates the corresponding cargo handling lever 25 (except for the lift lowering operation).
Is detected. The controller 50 includes switches 54 to 56
When a detection signal indicating that any one of the cargo handling levers 25 has been operated is input from, the cargo handling motor 41 is operated.

The drive wheel speed sensors 57 and 58 detect a gear (not shown) fixed to the output shaft of the traveling motor 21 as an object to be detected, so that a frequency proportional to the motor speed (rotation speed) N is obtained. Generate and output a pulse signal. Each of the rotation speed sensors 57 and 58 has a phase of the object to be detected of 9
The two pulse signals input from the controller 50 from each other are shifted in phase by 0 °, and the phase shift directions of the two pulse signals are reversed according to the rotation direction of the traveling motor 21. The controller 50 determines the motor rotation speed N by counting the number of input pulses per unit time of the pulse signal, and determines the motor rotation direction, that is, the traveling direction of the vehicle, by observing the direction of the phase shift between the two pulse signals. .

The steering angle sensor 59 is connected to the steering gear 3.
In the vicinity of 2A, the straight traveling state is set to “0”, and the steering angles θ of the right steering and the left steering are detected, and the detection signals are output to the controller 50.

The controller 50 includes a microcomputer (hereinafter simply referred to as a microcomputer) 60 and a motor drive circuit 61 including a three-phase inverter circuit and the like.
The microcomputer 60 stores a map M shown in FIG. 6 and a control program shown in FIG. 7 in a memory, and performs various controls by executing the control program.

The microcomputer 60 includes a traveling direction detection switch 5
The traveling motor 21 is controlled in the motor rotation direction according to the accelerator operation direction based on the forward / reverse signals SF and SR input from the ECU 2 and 53. Further, the microcomputer 60 obtains a target torque (motor torque) by referring to a map M in FIG. 6 based on two parameters of the accelerator opening Acc and the motor speed N, and obtains the target torque, a torque increasing speed described later, Is output to the motor drive circuit 61 to control the torque of the traveling motor (AC induction motor) 21. The traveling motor 21 is controlled by the motor drive circuit 61 to a current and a frequency corresponding to the torque command value.

In this map M, the accelerator operation direction is a positive (plus) direction. If the motor rotation direction is the same as the accelerator operation direction, the motor rotation speed at that time is set to a "positive" value, and the motor rotation If the direction is a negative direction opposite to the accelerator operation direction, the motor rotation speed at that time is set to a “negative” value. In the map M, the region where the accelerator operation direction is the same as the traveling direction and the motor rotation speed N takes a positive value is the powering mode, and the accelerator operation direction is opposite to the traveling direction and the motor rotation speed N is a negative value. The region to be taken is in the regeneration mode. The regeneration mode is set during the switchback operation.

The microcomputer 60 is set with a torque increasing speed (or a torque decreasing speed) until the target torque rises (or falls) to the target torque, and the torque increasing value (decreasing value) for each control cycle is increased. It is set in advance according to the speed (or the torque lowering speed).

The microcomputer 60 executes a torque limit control program shown in FIG. In the torque limit control program, the microcomputer 60 reviews the control content when performing torque control of the traveling motor 21 based on the steering angle θ detected based on the input signal from the steering angle sensor 59. That is, when the target torque is determined with reference to the map M in FIG. 6, the microcomputer 60 predicts whether or not the vehicle will turn with a small turning radius of a certain value or less based on the steering angle θ. When turning is predicted, the target torque and the command value for limiting the torque increasing speed are reviewed.

A method for predicting the turning of the vehicle will be described below. As shown in FIG.
0, the steering angle θ =
Steering up to 80 °, steering angle θ = 1 when steering left
Steering is possible up to 00 °. The maximum steering angle when the steering wheel 26 is fully turned (right steering θ = 80 ° or left steering θ)
= 100 °), the in-situ turning around the center O between the left and right front wheels 11, 11 as the turning center is possible.

FIG. 5 is a graph showing the relationship between the steering angle θ and the starting resistance. In this graph, the horizontal axis is the steering angle θ, and the vertical axis is the starting resistance. The starting resistance is represented by the product of the running rolling resistance of the front wheels 11, 11 and the drive steering wheel 12, and the weight. The starting resistance takes the maximum value fo when the vehicle is traveling straight at the steering angle θ = 0 °, and the value gradually decreases as the steering angle θ increases.

For example, at the time of starting (motor rotation speed N = 0), the vehicle is accelerated at the time of starting by subtracting the starting resistance from the driving force of the drive steering wheel 12 corresponding to the target torque determined by the operation amount of the accelerator lever 24. Therefore, the starting acceleration increases as the steering angle θ increases.
Therefore, the target torque is limited in a steering angle region where the starting resistance is equal to or less than fs so that the driver in the driver's seat 22 is hardly swung in the lateral direction (left / right direction) by receiving an excessively large force. I am trying to do it. Specifically, a steering angle region in which the steering angle θ is 60 ° or more for right steering and a steering angle θ of 80 ° or more for left steering is set as the torque limiting angle region.

In the torque limit control program, when the steering angle θ of the drive steered wheels 12 is within the torque limit angle region indicated by hatching in FIG. 4, the target torque and the torque increase speed are set to be limited. Note that the graph of FIG. 5 shows the starting resistance under the condition that the mast device 15 is reach-out, and under the condition that the mast device 15 is reached, the starting resistance shifts to the side where the starting resistance becomes large. Therefore, the torque limiting angle range is set in accordance with the starting resistance under a more severe reach-out condition in which a large acceleration is generated when the vehicle turns. Of course, it is also possible to adopt a method in which a reach sensor for detecting the reach amount of the mast device 15 is provided, and the torque limit angle region is changed according to the value detected by the reach sensor.

The method for limiting the target torque is as follows. When the steering angle θ exceeds the preset threshold value and is in the torque limiting angle range, the target torque obtained from the map M for normal operation in FIG.
) To limit the target torque to be smaller than the normal value by a predetermined ratio, thereby limiting the driving torque of the traveling motor 21. It should be noted that instead of the method of limiting the target torque obtained from the map by a calculation process, a torque limiting map may be used instead of the normal driving map when the steering angle θ is in the torque limiting angle region in advance. .

During operation of the vehicle, the microcomputer 60 controls each sensor 5
Motor speed N and accelerator opening Acc are obtained based on the input signals from 1, 57 and 58, and these parameters N and A are obtained.
Based on cc, a target torque is determined with reference to a map M in FIG. When the target torque is determined, the vehicle speed V in the powering mode
When the vehicle speed is below the set vehicle speed Vs at which sudden acceleration can occur,
In the regeneration mode, the microcomputer 60 executes the torque limit control program shown in FIG. Hereinafter, the torque limit control program will be described.

In step (hereinafter simply referred to as "S") 10, the steering angle θ is detected. In S20, it is determined whether or not the steering angle θ is within the torque limit angle region, that is, is not less than right turning 60 ° or not less than left turning 80 °.
If the steering angle θ is within the torque limit angle region, the process proceeds to S30, and if not, the subroutine is terminated.

In S30, the target torque is reduced. That is, the target torque obtained by referring to the map M of FIG. 6 is multiplied by the correction coefficient B, and the target torque is changed to a small value reduced by a preset ratio.

In the next S40, the torque increasing speed is reduced. That is, the torque increase value, which is an increment for increasing the target torque, is decreased for each control cycle. Next, the operation of the reach type forklift will be described.

When the vehicle is operating (key on),
Detection signals from various sensors 51, 52, 53, 57, 58, 59 and the like are input to the controller 50. For example, the steering wheel 26 is operated in the vicinity of the straight ahead,
Is outside the torque limit angle range, the steering angle θ is out of the torque limit angle range (right steering θ <60 ° or left steering θ <80 based on the detection signal from the steering angle sensor 59).
The microcomputer 60 determines that the condition (1) is satisfied. Also handle 2
6 is almost full and the steering angle of the drive steered wheels 12 is within the torque limit angle region, the steering angle θ is set based on the detection signal from the steering angle sensor 59 in the torque limit angle region (right steering θ ≧ 60 ° or left steering θ ≧ 80 °).

When the vehicle is stopped, the motor speed N =
Since 0 (rpm) and the accelerator opening Acc = 0, the target torque “0” is obtained with reference to the map M, the driving motor 21 is not driven, and the vehicle is kept stopped.

In this state, when the driver starts the reach-type forklift 10 and suddenly operates the accelerator lever 24 from the neutral position to almost the forward side, the accelerator opening Acc and the motor speed N (= 0) at that time. ), The target torque is determined with reference to the map M, and the torque increase value for each control cycle is determined.

Next, the microcomputer 60 determines whether or not the steering angle θ is within the torque limit angle region. For example, if the drive steered wheels 12 are directed straight ahead, the previously determined target torque and torque increase value are adopted. As a result, the traveling motor 21 is torque-controlled so that the normal target torque obtained from the map M is obtained. At this time, the steering angle θ does not reach the torque limit angle region and the starting resistance is relatively large. Therefore, even if the traveling motor 21 is controlled with the normal target torque, the forklift 10 starts with an appropriate acceleration.

On the other hand, when the steering angle θ is within the torque limit angle region (θ ≧ right turn 60 ° or θ ≧ left turn 80 °), the previously determined target torque is reduced by a preset ratio. The torque rise speed is limited to a small value. As a result, the torque of the traveling motor 21 is controlled so that the output torque increases at a relatively gentle increasing speed up to the limited target torque. Therefore, the steering angle θ
Is within the torque limiting angle range, the starting resistance (running resistance) is as small as the value fo or less as shown in FIG.
The vehicle starts at an appropriate acceleration corresponding to the operation amount of the accelerator lever 24 without sudden start.

Therefore, even if the driver does not know that the drive steered wheels 12 are severely cut, and even if the accelerator lever 24 is suddenly operated to make a straight run, the vehicle is prevented from suddenly turning and the acceleration is substantially the same as when the vehicle is running straight. Start turning. As a result, the operator is not pressed against the inner side wall of the driver's seat 22 or surprised.

The vehicle speed V is not limited to the time when the vehicle starts, and the vehicle speed V is the set vehicle speed V.
During the period of s or less, even when the accelerator lever 24 is accelerated during turning, if the steering angle θ is within the torque limiting angle range, the target torque and the torque increasing speed are limited. As a result, even when accelerating during the turning travel, the vehicle turns with the same acceleration as that in the straight running corresponding to the accelerator operation amount, thereby avoiding sudden acceleration against the operator's intention.

Further, when the accelerator lever 24 is switched back during the turning operation to enter the regeneration mode,
If the steering angle θ is within the torque limiting angle range, the target torque and the torque increasing speed are limited. As a result, when the switchback operation is performed during the turning of the vehicle, the regenerative braking force is reduced, and the vehicle is braked with the same braking force as when the vehicle is traveling straight according to the switchback operation amount. Therefore, the regenerative braking force is strong against the operator's will, and for example, the operator is prevented from being pressed against the inner wall of the driver's seat 22.

According to the reach type forklift of the present embodiment described in detail above, the following effects can be obtained. (1) When the steered wheels 12 are sharply cut and the steering angle θ is within the torque limit angle range, control is performed to limit the target torque of the traveling motor 21 to a small value, thereby preventing the vehicle from suddenly starting. be able to. For this reason, even if the driver does not know that the drive steerable wheels 12 are sharply cut off and suddenly operates the accelerator lever 24 to the full position for the straight running, sudden start accompanied by turning is prevented.
It will not be pressed or surprised against the inner wall of the second.

(2) By using the steering angle sensor 59, it is possible to predict beforehand that the vehicle will turn before starting from the steering angle θ, so that the torque limiting control can be executed from the beginning of starting. Therefore, the torque limit control is started without delay with the start operation of the accelerator lever 24, and it is possible to reliably avoid a sudden turning start contrary to the operator's intention.

(3) When the steering angle θ is within the torque limiting angle range, the control for limiting the target torque is performed not only at the time of starting but also at the time of acceleration during traveling. Even if the vehicle is suddenly operated, the vehicle is prevented from suddenly accelerating unexpectedly.

(4) Even when the accelerator lever 24 is switched back during turning while the steering angle θ is within the torque limit angle range, the torque limit control is performed and the regenerative braking force is reduced, so that the operator's Unintended sudden braking prevents the operator from being pressed or surprised against the inner wall of the driver's seat 22.

(5) Since the torque limiting control employs both the limitation of the target torque and the limitation of the speed of increasing the torque, it is possible to effectively prevent sudden turning acceleration during starting or running acceleration.

(6) Since an AC induction motor is used as the traveling motor 21 and torque control is employed, the precision of control can be improved by directly controlling the torque.
It is possible to almost certainly prevent sudden turning and sudden acceleration.

The embodiment is not limited to the above, and can be carried out, for example, in the following manner. In the above-described embodiment, the target torque is limited only when the steering angle θ exceeds the threshold, but for example, the reduction rate for limiting the target torque is continuously increased as the steering angle θ increases in the entire steering angle range. Alternatively, it can be changed intermittently. Of course, a configuration may be employed in which the reduction rate of the target torque is changed continuously or intermittently in a range where the steering angle θ exceeds the threshold value. Further, the reduction rate of the target torque can be changed in accordance with two parameters of the steering angle θ and the accelerator opening Acc.

The steering angle detecting means for predicting the turning of the vehicle includes a steering angle sensor 5 for detecting the steering angle of the drive steered wheels 12.
It is not limited to nine. For example, a steering wheel angle sensor that detects the steering angle of the steering wheel 26 can be used. In addition, the steering angle can be obtained by detecting the movement of other components that move in conjunction with the steered wheels and have a substantially unique positional relationship.

Further, the steering angle sensor 59 is used to drive the steered wheels 12.
Is a sensor that continuously detects the steering angle θ, but is not limited to such a sensor that can continuously detect the steering angle θ, and a switch can also be used. For example, a switch for detecting that the drive steerable wheel 12 has reached the threshold steering angle is provided, and the switch is turned on upon hitting a detected part (dog) provided on a component that moves in conjunction with the steering of the drive steerable wheel 12. Sometimes it is determined that the steering angle of the drive steered wheels 12 has exceeded a threshold. Of course, the switch and the dog may be mounted in reverse.
In addition, the same configuration can be adopted for other components such as the steering wheel 26 linked to the drive steering wheel 12 to detect that the steering angle exceeds the threshold value by using such a switch.

In the above-described embodiment, the torque limiting control is performed in consideration of only the steering angle θ of the drive steered wheels 12. However, whether the torque is limited by using the steering angle θ and the accelerator opening Acc as parameters. May be determined. For example, when the steering angle θ is large, the target torque is limited even when the accelerator opening Acc is small, and when the steering angle θ is small, the target torque is limited when the accelerator opening Acc is large.
For example, if it is determined from two parameters θ and Acc that the starting acceleration exceeds a certain threshold, the torque is limited.

The method is not limited to the method of predicting the turning of the vehicle from the steering angle θ using the steering angle sensor 59. The turning of the vehicle can be directly detected. For example, an acceleration sensor or a yaw rate sensor is attached to the vehicle body, and the turning of the vehicle body is directly detected based on the lateral acceleration acting on the vehicle body and the yaw rate (turning angular velocity) of the vehicle body. At the time of start, for example, a sign that the vehicle will suddenly start turning is detected when the lateral acceleration of the vehicle or the yaw rate of the vehicle exceeds a threshold value. If the sign is detected, a torque limit control program is executed. According to this method, although the start of the torque limiting control involves a slight delay, it is possible to avoid the occurrence of a sudden acceleration accompanying a turn contrary to the driver's will, such as a sudden start of the turn.

It is also possible to adopt a method of measuring the acceleration of the drive steered wheels. For example, the drive torque is limited only when the acceleration of the drive steered wheels is greater than the maximum acceleration when traveling straight. At this time, it is preferable that the acceleration can be measured in a state where the driven steering wheel is not slipping, because the slipping of the driven steering wheel causes erroneous detection.
The fact that the vehicle is not slipping can be determined, for example, by using the slippage speed (=) using the driven wheel converted vehicle speed Vf obtained from the front wheel rotation speed detection value and the drive wheel conversion vehicle speed Vd obtained from the drive steering wheel rotation speed detection value. Vf-Vd) and the slip ratio (= (Vf-V
d) / Vf) is calculated, and the presence or absence of slip is determined based on the calculated value. Further, the acceleration of the driver's seat portion is indirectly predicted by calculation from the steering angle θ and the driven wheel converted vehicle speed obtained from the detected value of the rotation speed of the front wheels, and the output of the traveling motor 21 is calculated so that this acceleration does not exceed the threshold value. Can also be restricted.

The timing for performing the torque limiting control can be appropriately selected, for example, (1) only at the time of starting, (2) only at the time of starting and switchback, (3) only at the time of starting and acceleration during running. For example, only at the time of start, the stop vehicle speed Vo at which the vehicle can be regarded as stopped
(For example, the torque limit control is performed only when the vehicle is started from a state where 0 ≦ Vo <2 (km / h), and the torque limit control is terminated when the vehicle speed exceeds a threshold value of the start vehicle speed. In some cases, the torque limiting control is not performed, and when the torque limiting control is completed, control may be performed so that the driving torque gradually approaches the normal target torque.

In the above-described embodiment, both the target torque and the torque increasing speed are limited, but a method of limiting only one of them can be adopted. For example, only the target torque is limited. In this case, the maximum driving force of the drive steered wheels is limited to a small value. Also, for example, only the torque increasing speed is limited. Also in this case, when the accelerator lever is fully operated for the start, after reaching the start end speed at which the start process is completed, if the torque rising speed is set to be slow enough to finally reach the target torque, the drive steering wheel is started in the start process. Is limited to a small value.

If the forklift is restarted immediately after stopping and the stop time is short enough not to be considered that the driver has been replaced, it is assumed that the driver is aware of the steering angle θ of the drive steered wheels 12. Regardless, even when the vehicle starts turning, the limitation of the driving torque is stopped.

The method of limiting the driving torque can be set as appropriate, and a method of limiting the target torque so as not to exceed a preset upper limit value (limit value) may be used. That is, while the target torque is equal to or less than the upper limit (limit value), the control is performed with the normal target torque obtained from the map M, and the target torque is changed to the upper limit only when the target torque exceeds the upper limit. In this case, the upper limit may be constant in the torque limit angle region, or the upper limit is set such that the value continuously or intermittently changes so as to take a smaller value as the steering angle θ increases in the torque limit angle region. Is also good.

The torque value after being limited at the time of turning start can be set to an appropriate value as long as it is limited with respect to the value at the time of normal operation (at the time of straight running). For example, as a result of the torque limitation, the starting acceleration at the time of turning start may be larger than the starting acceleration at the time of straight traveling because the reduction rate of the torque limitation is small, and the starting acceleration at the time of straight traveling because the reduction rate of the torque limitation is large. It can be smaller. In short, it can be appropriately set depending on how much the lateral force received by the driver is to be reduced.

In the above-described embodiment, the method of limiting the output torque of the driving means such as the traveling motor is employed. However, although the energy is wasteful, the turning is performed when the steering angle θ is within the torque limiting angle range. A method of alleviating the starting acceleration by weakly applying the brake during acceleration may be adopted.

The method for limiting the driving torque is not limited to the method for reducing the target torque. For example, a control method for alleviating the drive torque can be adopted by performing control to repeat on / off of the drive torque at a high frequency.

The traveling motor 21 may be a DC motor. In this case, when the steering angle θ is within the torque limit angle region, the drive voltage (drive current) that determines the output of the DC motor is limited to a small value to limit the output torque.

The operation means is not limited to the accelerator lever. An accelerator pedal may be used. Further, in an industrial vehicle in which the acceleration is set in advance, an operation switch such as an operation button for performing an operation of starting the vehicle may be used.

The steering wheels of the industrial vehicle are not limited to the driving wheels. For example, the present invention may be applied to a battery type forklift having a rear wheel as a steering wheel and a front wheel as a driving wheel, such as a counterbalance type forklift. Further, the industrial vehicle can be adopted for an industrial vehicle in which the steered wheels are front wheels. Further, the industrial vehicle may be of a three-wheel or four-wheel drive type. Further, the present invention is not limited to industrial vehicles in which the steered wheels are rear wheels. An industrial vehicle in which the drive steered wheels are front wheels and a standing-type driver's seat is arranged near the front wheels. Even with these configurations, it is possible to avoid sudden turning by limiting the driving torque of the driving wheels when the turning of the vehicle is predicted or detected based on the detected value such as the steering angle of the steered wheels. .

The present invention is not limited to electric industrial vehicles (battery vehicles). In the case of an engine vehicle, when a sudden turning acceleration is predicted or detected, the target value of the accelerator opening at the time of starting is limited, and the driving force of the drive wheels is weakened by controlling the connection pressure of the hydraulic clutch to make the turning sudden. Control to prevent starting.
In this case, the driving means is constituted by the engine, and the control means is constituted by the controller for controlling the engine.

The technical ideas other than the claims ascertained from the above embodiments are described below. (1) before SL drive means is an electric motor. (2) when the steering wheel steering angle detected by the pre-Symbol steering angle detecting means as exceeds the threshold value is off from the straight, said control means, so as to limit the maximum driving force of the driving wheel And controlling the driving means.

[0087] (3) before SL industrial vehicle includes a traveling direction selection operation means for switching the forward and backward (24), when the traveling direction selection operation means is switched back operation, the control means rotate the drive wheel Controlling the driving means so as to reverse the direction, and detecting the turning of the vehicle based on the detection value of the detection means, the driving means so as to limit the maximum driving force of the driving wheels during the switchback. Control means. In this case, the maximum braking force of the driving wheels is limited at the time of switchback during turning of the vehicle, so that the force that the driver swings sideways can be reduced.

[0088] (4) before Symbol detection means predicts or detects a pivoting may serve the turn acceleration exceeding a predetermined value to the vehicle. In this case, the maximum driving force of the drive wheels is limited when the vehicle is predicted or detected to be able to turn with a turning acceleration equal to or greater than a certain value. In the above-described embodiment, the turning in which the turning acceleration equal to or more than a certain value can work is the turning in which the starting resistance is equal to or less than the value fs in the entire steering angle range (θ> 0) where the turning is performed in FIG. It refers to right steering 60 ° or more or left steering 80 ° or more.

[0089] (5) before SL electric motor is an AC motor, said control means the electric motor torque control based on the target torque determined the operating amount of said operating means as one parameter, the maximum of the driving wheel The target torque is limited as control for limiting the driving force.

[0090] (6) The pre-SL control means control for limiting the maximum driving force of the driving wheel, limits the torque increase rate up launch to the target torque.

[0091] (7) before SL control means continuously up driving force to the steering angle so as to limit further reduce the maximum driving force of the driving wheel as the steering angle detected increases by the steering angle detection means The driving means or the electric motor is controlled so as to limit the electric power intermittently or intermittently.

[0092] (8) before Symbol detection means is a turning detection means for detecting turning of the vehicle, wherein, when said turning detecting means detects the turning of the vehicle, the driving force of the driving wheel The driving means (electric motor) is controlled so as to limit the driving.

[0093] (9) before SL turning detection means comprises an acceleration sensor. In this case, when the turning acceleration during the turning of the vehicle is detected by the acceleration sensor and the turning of the vehicle is detected based on the detected value of the turning acceleration, the driving force of the drive wheels is limited to a small value. For example, even if the vehicle is started to turn, the turning acceleration felt by the driver for the operation amount of the operation means can be suppressed to a small value.

[0094] (10) before SL turning detection means comprises a yaw rate sensor. In this case, when the turning angle at the time of turning of the vehicle is detected by the yaw rate sensor and the turning of the vehicle is detected based on the detected value of the turning angle, the driving force of the drive wheels is limited to a small value. For example, even if the vehicle is started to turn, the turning acceleration felt by the driver for the operation amount of the operation means can be suppressed to a small value.

[0095] (11) industrial vehicle is standing room type. It is a standing type and the driver is in an unstable position compared to the seat,
Since a sudden turning start can be avoided, there is no fear that the driver may be surprised or lose his posture.

[0096] (12) industrial vehicle equipped with the travel control device of the industrial vehicle.

[0097]

According to the invention described in the claims according to the present invention, since limiting the maximum driving force of the driving wheels as the vehicle acceleration is suppressed during the vehicle turning, a driver when the vehicle turning is subjected to a lateral force Can be alleviated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a travel control device of a reach type forklift.

FIG. 2 is a side view of a reach type forklift.

FIG. 3 is a partially broken plan view.

FIG. 4 is a schematic plan view of the vehicle for explaining a torque limit range of a steering angle.

FIG. 5 is a graph showing a relationship between a steering angle and a starting resistance.

FIG. 6 is a map diagram for motor control.

FIG. 7 is a flowchart illustrating torque limiting control.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Reach type forklift truck as an industrial vehicle, 11 ... Front wheel, 12 ... Driving steering wheel as a driving wheel and a steering wheel, 21 ... Running motor as a driving means and an electric motor, 22 ... Standing type driver's seat, 24 ... Accelerator lever as operating means, 50 ... Controller as control means, 59 ... Steering angle sensor as steering angle detecting means, 60
... Microcomputer constituting control means, Acc. Accelerator opening, N. motor rotation speed, θ.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-92931 (JP, A) JP-A-10-73033 (JP, A) JP-A-5-162995 (JP, A) JP-A-11-129 322298 (JP, A) JP-A-3-27701 (JP, A) JP-A-7-144649 (JP, A) JP-A-61-272593 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60L 1/00-3/12 B60L 7/00-13/00 B60L 15/00-15/42 F02D 29/02

Claims (5)

(57) [Claims] 1. A traveling control device for an industrial vehicle that controls driving means for driving driving wheels of an industrial vehicle based on an operation of an operating means, wherein detection for obtaining a detection value for predicting or detecting turning of the vehicle is provided. Means, when the turning of the vehicle is predicted or detected based on the detection value of the detecting means, the driving means is controlled so as to limit the maximum driving force of the driving wheels so as to limit the acceleration of the vehicle during turning of the vehicle. Control means , wherein the control means turns the vehicle based on a detection value of the detection means.
When the number of times is predicted or detected,
The climb speed is limited to a smaller value than when traveling straight.
And a driving control device for an industrial vehicle. 2. A driving means for driving a driving wheel of an industrial vehicle.
Travel control of industrial vehicles controlled based on operation of operation means
The device obtains a detection value for predicting or detecting turning of the vehicle.
Prediction or detection and eye detection means, the turning of the vehicle based on the detected value of said detecting means
The vehicle acceleration when turning the vehicle.
The driving means so as to limit the maximum driving force of the driving wheels.
Control means for controlling the turning of the vehicle based on the detection value of the detection means.
When the number of times is predicted or detected, the maximum
Both output torque and torque increase speed are
A travel control device for an industrial vehicle that controls the drive unit so that the drive unit is limited to an extremely small value . 3. The steering device according to claim 1, wherein the detecting means controls a steering wheel of the industrial vehicle.
Steering angle detecting means for detecting a steering angle, wherein the control means detects the steering angle by the steering angle detecting means .
Claim 1 or claim predict the turning of the vehicle based on a steering angle
3. The travel control device for an industrial vehicle according to 2 . 4. An operation amount of said operation means, wherein said control means is an operation amount of said operation means.
Limit the output value of the driving means determined according to
4. The method according to claim 1 , wherein the driving means is controlled in such a manner .
The travel control device for an industrial vehicle according to claim 1 . 5. In an industrial vehicle, one of a front wheel and a rear wheel is driven.
Steering wheels, of which the front and rear wheels are closer to the drive steering wheels.
The traveling control device for an industrial vehicle according to any one of claims 1 to 4, wherein the arranged driver's seat is of a standing type .