JP2000062428A - Car body swinging controller for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the stability of a vehicle and comfortableness. SOLUTION: This controller is constructed in such a manner that a driving wheel 3 and an auxiliary wheel 4 disposed in the left and right side of the car body of an industrial vehicle are suspended on the car body via a linking mechanism 20 so as to permit the swinging of the car body in a rolling direction, and the auxiliary wheel 4 is attached to the linking mechanism 20 via a capstan spring 30, and adapted to control the swinging of the car body. In this case, a first swinging regulating mechanism for locking the swinging of the driving wheel 3 and the linking mechanism 20 to the car body is provided between the driving wheel 3 and the car body, and a second swinging regulating mechanism for locking the swinging of the auxiliary wheel 4 to the car body is provided between the auxiliary wheel 4 and the car body.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a reach type forklift, etc.
In an industrial vehicle including a suspension in which a drive wheel and an auxiliary wheel are connected to a vehicle body by a link mechanism so that the vehicle wheel can swing in the roll direction, a control that locks the link mechanism and restricts the vehicle body from swinging in the roll direction. The present invention relates to a vehicle body swing control device for an industrial vehicle.

[0002]

2. Description of the Related Art For example, as a reach type forklift truck as an industrial vehicle, there is a three-wheel type vehicle having two front wheels and one rear wheel. In this three-wheeled vehicle type, an auxiliary wheel is usually provided at the rear part of the vehicle body so as to make a pair with one rear driving wheel. The drive wheels and auxiliary wheels are suspended by a link mechanism with respect to the vehicle body frame to allow swinging of the vehicle body in the roll direction, and suspension springs and dampers are provided between the vehicle body and the link mechanism. Rear suspension is configured.

For example, when traveling on an uneven road surface, the drive wheels and the auxiliary wheels swing with respect to the vehicle body by the movement of the link mechanism to absorb the unevenness of the road surface and stabilize the posture of the vehicle body in the lateral direction. Has been planned. However, when the forklift turns, a lateral force due to centrifugal force acts laterally on the vehicle body, but this suspension function causes the vehicle body to tilt back greatly, which reduces the stability of the vehicle body during turning. It was.

Therefore, in JP-A-6-191250 and JP-A-6-191251, an acceleration sensor is provided in a reach type forklift, and the tilt acceleration (lateral acceleration) detected by the acceleration sensor is a predetermined value or more. There is disclosed a suspension device in which the opening / closing valve is closed and the cylinder device interposed between the vehicle body frame and the link mechanism is locked when the temperature reaches 0. According to this forklift, when the tilt acceleration reaches a predetermined value or more during turning,
Since the link mechanism is fixed to the vehicle body frame and the swinging of the vehicle body in the roll direction is restricted, the lateral inclination of the vehicle body is suppressed to be small, and it becomes easy to maintain a stable vehicle body posture during turning.

[0005]

However, the above-mentioned conventional vehicle body swing control device for an industrial vehicle has the following problems. That is, in the above-mentioned reach type forklift, in order to absorb the impact caused by the riding of the auxiliary wheels and improve the riding comfort, it is attached to the link mechanism via an elastic member such as a caster spring.

Therefore, when the forklift turns in the direction in which the auxiliary wheel is the outer wheel, even if the tilting acceleration becomes a predetermined value or more and the cylinder device is locked, the caster spring will not move from the body posture when locked. If there is still room for compression deformation due to lateral acceleration, the caster spring will compress and deform, and the vehicle body will tilt further laterally.

Further tilting of the vehicle body is not a problem as long as the tilting is within a safe range. However, when the cylinder device is locked and the drive wheels are fixed to the vehicle body frame, the vehicle body tilts in the lateral direction, and the drive wheels tend to lift from the road surface. As a result, the ground pressure of the drive wheels may drop, and in some cases the drive wheels may rise above the road surface.

The present invention has been made in view of the above conventional problems, and it is an object of the present invention to provide a vehicle body swing control device for an industrial vehicle having a high vehicle body stability and a comfortable ride.

[0009]

According to a first aspect of the present invention, a drive wheel and an auxiliary wheel disposed on the left and right of a vehicle body of an industrial vehicle are linked to the vehicle body so as to allow the vehicle body to roll in a roll direction. It is suspended via a mechanism, and the auxiliary wheel is attached to the link mechanism via an elastic member.
In a vehicle body rocking control device for controlling the vehicle body rocking, the vehicle body rocking control device locks rocking of the drive wheel and the link mechanism with respect to the vehicle body between the drive wheel and the vehicle body. A vehicle body of an industrial vehicle, comprising: a first rocking regulation mechanism; and a second rocking regulation mechanism for locking the rocking of the auxiliary wheel with respect to the vehicle body, between the auxiliary wheel and the vehicle body. It is in the swing control device.

What is most noticeable in the present invention is that the vehicle body swing control device includes, in addition to the first swing control mechanism,
Second for locking the swing of the auxiliary wheel with respect to the vehicle body
It is to have a rocking regulation mechanism.

Next, the function and effect of the present invention will be described.
When the vehicle turns in the direction in which the auxiliary wheel is the outer wheel, even if the first swing restriction mechanism operates, there is still room for the elastic member to compressively deform due to lateral acceleration due to the body posture when locked. Then, the elastic member is compressed and deformed, and the vehicle body further tilts in the lateral direction.

Therefore, the vehicle body swing control device has the second swing control mechanism. Therefore, when the vehicle body is further tilted after the first swing restricting mechanism is activated and the tilt may impair the stability of the vehicle,
The rocking regulation mechanism operates and the auxiliary wheels and the vehicle body can be locked. As a result, the conventional problem that the vehicle is tilted too much due to the presence of the elastic member provided to improve the riding comfort can be solved.

As described above, according to the present invention, it is possible to provide a vehicle body swinging control device for an industrial vehicle having a high vehicle body stability and a comfortable ride.

Next, according to a second aspect of the invention, the timing at which the second swing restricting mechanism operates is the first
It is preferable that it is later than the timing at which the swing restriction mechanism operates. With this, the second swinging restricting mechanism can be operated only after the first swinging restricting mechanism is actuated, and when there is a possibility that the vehicle body further tilts and the stability of the vehicle is impaired.

Therefore, even if the first swing restricting mechanism operates and the drive wheels and the link mechanism are locked to the vehicle body, the elastic member does not operate when the second swing restricting mechanism does not operate. Since it works, the impact on the auxiliary wheels from the road surface etc. is absorbed, and the riding comfort does not decrease.

Next, as in the invention described in claim 3, it is preferable that the link mechanism is attached to the vehicle body through a suspension spring. As a result, it is possible to improve the riding comfort by absorbing the impact that the driving wheels receive from the road surface or the like. Further, it is possible to prevent the wheel pressure of the drive wheels from decreasing on the road surface.

Next, as in the invention described in claim 4, when the expansion and contraction amount of the suspension spring reaches or exceeds the set value, the first swing restricting mechanism can be operated. Accordingly, the vehicle body swing control device can detect the magnitude of the vehicle body swing by the amount of expansion and contraction of the spring, and operate the first swing restriction mechanism.

Next, as in the invention described in claim 5, when the expansion / contraction amount of the elastic member reaches or exceeds the set value, the second swing restricting mechanism can be operated. As a result, the vehicle body swing control device can detect the magnitude of vehicle body swing based on the amount of expansion and contraction of the elastic member, and operate the second swing restriction mechanism.

Next, as in the invention described in claim 6, when the vehicle body swing control device has a lateral acceleration measuring means, when the measured value of the lateral acceleration applied to the vehicle reaches each set value or more. The first swing restriction mechanism and the second swing restriction mechanism may be operated respectively.

In this case, by measuring the lateral acceleration, the magnitude of rocking of the vehicle body can be detected, and the first rocking restricting mechanism and the second rocking restricting mechanism can be operated. Therefore, the set value is set to the first swing restriction mechanism and the second swing control mechanism.
By providing a difference between the swing control mechanism and the swing control mechanism, it is possible to easily shift the operation timings of the first swing control mechanism and the second swing control mechanism.

Next, as in the invention described in claim 7, the vehicle body swing control device has yaw rate measuring means, and when the measured value of the yaw rate applied to the vehicle reaches each set value or more, the above-mentioned It is also possible to operate each of the first swing restriction mechanism and the second swing restriction mechanism.

In this case, by measuring the yaw rate, the magnitude of rocking of the vehicle body can be detected, and the first rocking restricting mechanism and the second rocking restricting mechanism can be locked. Therefore, by making the set value different between the first swing restriction mechanism and the second swing restriction mechanism, the operation of the first swing restriction mechanism and the second swing restriction mechanism can be easily performed. The timing can be easily shifted.

Next, as in the invention described in claim 8, when the tilting angle of the link in the link mechanism reaches or exceeds each set value, the first swing restricting mechanism and the second swing restricting mechanism. It is also possible to activate each mechanism.

In this case, by measuring the tilt angle, it is possible to detect the magnitude of rocking of the vehicle body and operate the first rocking restricting mechanism and the second rocking restricting mechanism. Therefore, the set value is set to the first swing restricting mechanism and the second swing restricting mechanism.
By providing a difference between the swing control mechanism and the swing control mechanism, it is possible to easily shift the operation timings of the first swing control mechanism and the second swing control mechanism.

Next, as in the invention described in claim 9, the vehicle body swing control device is provided with a turning change measuring means for measuring a yaw rate change rate or a lateral acceleration change rate of the vehicle, and the yaw rate change rate or the yaw rate change rate is measured. When the rate of change in lateral acceleration reaches or exceeds the set value, at least the first swing restriction mechanism may be activated.

In this case, at least when the yaw rate change rate or the lateral acceleration change rate in which the value rises rapidly at the time of turning exceeds the set value, at least the first swing restriction mechanism is operated. Therefore, at the start of turning, the drive wheels and the link mechanism are quickly locked to the vehicle body with no timing delay.

Next, as in the invention described in claim 10,
Regarding the timing of the operation of the second swing restriction mechanism,
The yaw rate change rate or the lateral acceleration change rate, which is the measurement value of the turning change measurement means, may be set not to be considered as a parameter for the lock control determination.

In this case, the yaw rate change rate or the lateral acceleration change rate measured by the turning change measuring means is not taken into consideration as the parameter for the lock control determination in the operation of the second rocking regulation mechanism. Therefore, it does not prevent the link mechanism from being locked after the vehicle body is tilted toward the auxiliary wheels by a predetermined angle. That is, it becomes possible to keep the second swing restriction mechanism inoperative until the vehicle body is further tilted to some extent after the first swing restriction mechanism is activated. Therefore, the riding comfort can be improved.

Next, as in the invention described in claim 11,
The lateral acceleration measuring means can selectively measure only the lateral acceleration when the vehicle is turning. As a result, only the lateral acceleration when the vehicle is turning is selectively measured by the lateral acceleration measuring means. Therefore, the lateral acceleration generated when the vehicle body leans to the left or right due to the unevenness of the road surface when the vehicle is not turning is not subject to the lock control, and the sway of the vehicle body due to the unevenness of the road surface is absorbed by the link mechanism.

Next, according to the invention of claim 12,
The lateral acceleration measuring means calculates the lateral acceleration by a steering angle detector that detects the steering angle of the steered wheels, a vehicle speed detector that detects the vehicle speed of the vehicle, and a calculation using both the steering angle and vehicle speed detection data. A lateral acceleration estimating means for estimating may be provided.

In this case, the lateral acceleration is calculated by using the steering angle data of the steered wheels detected by the steering angle detector and the vehicle speed data of the vehicle detected by the vehicle speed detector. Estimated by. for that reason,
By using the above steering angle data, it becomes possible to selectively detect only the lateral acceleration during turning. Also,
As the vehicle speed detector, it is possible to use one that is originally prepared for the vehicle.

Next, as in the invention described in claim 13,
The lateral acceleration measuring means includes a yaw rate detector for detecting a yaw rate of the vehicle, a vehicle speed detector for detecting a vehicle speed of the vehicle, and a lateral acceleration estimation for estimating a lateral acceleration by calculation using both the yaw rate and vehicle speed detection data. And means.

In this case, the lateral acceleration is estimated by the lateral acceleration estimating means by a calculation using the yaw rate data of the vehicle detected by the yaw rate detector and the vehicle speed data of the vehicle detected by the vehicle speed detector. . Therefore, by using the yaw rate data, it becomes possible to selectively detect only the lateral acceleration during turning. Further, as the vehicle speed detector, the one originally prepared for the vehicle can be used.

Next, as in the invention described in claim 14,
The lateral acceleration measuring means may be an acceleration sensor, and may include turning determination means for determining whether or not the lateral acceleration detected by the acceleration sensor is during turning of the vehicle.

In this case, the turning determination means determines whether or not the lateral acceleration detected by the acceleration sensor is the one when the vehicle is turning. Therefore, even in the configuration in which the lateral acceleration is directly detected by using the acceleration sensor, only the lateral acceleration during turning can be selectively detected.

Next, as in the invention described in claim 15,
The turning change measuring means is detected by a vehicle speed detector for detecting the vehicle speed of the vehicle, a detector provided for measuring the lateral acceleration other than the vehicle speed detector, and both detectors. It is also possible to provide a turning change rate estimating means for estimating the yaw rate change rate or the lateral acceleration change rate by calculation using two detection data including vehicle speed detection data.

In this case, two detection data detected by a vehicle speed detector for detecting the vehicle speed and a detector provided for measuring the lateral acceleration other than the vehicle speed detector are used. By the calculation, the yaw rate change rate or the lateral acceleration change rate is estimated by the turning change rate estimation means. Therefore, the detector provided to measure the lateral acceleration can be used to estimate the yaw rate change rate or the lateral acceleration change rate, and the vehicle speed detector originally provided in the vehicle is used. It is possible.

Next, as in the invention described in claim 16,
The vehicle body swing control device includes the first swing control mechanism and the second swing control mechanism after a predetermined time has elapsed from the time when the lock condition for operating the first swing control mechanism and the second swing control mechanism is not satisfied. It is preferably set so as to stop the operation of the swing restriction mechanism.

In this case, the operation of the rocking regulation mechanism is stopped after a lapse of a predetermined time from the time when the lock condition for operating the rocking regulation mechanism is not established. Therefore, when the measured values of the lateral acceleration and yaw rate change rate happen to fall near the set values, or when the measured values of the lateral acceleration and yaw rate change rate are both used as lock control parameters, the lateral acceleration and yaw rate change rate are changed. Even if a slight timing deviation occurs when the ratio becomes a value higher than each set value, frequent switching without control is avoided.

Next, according to the invention of claim 17,
The set values when the operations of the first swing restriction mechanism and the second swing restriction mechanism are stopped are set to be smaller than the set values when the first swing restriction mechanism and the second swing restriction mechanism operate. Preferably.

In this case, even if the rocking restricting mechanism is operated, the operation of the rocking restricting mechanism is not stopped unless the value is smaller than the set value when the operation is stopped and is smaller than the set value when the operation is stopped. Therefore, when the measured values of the lateral acceleration and yaw rate change rate happen to fall near the set values, or when the measured values of the lateral acceleration and yaw rate change rate are both used as lock control parameters, the lateral acceleration and yaw rate change rate are changed. Even if a slight timing deviation occurs when the ratio becomes a value higher than each set value, frequent switching without control is avoided.

Next, according to the invention of claim 18,
The first rocking regulation mechanism includes regulation force adjusting means capable of adjusting the regulation force applied to the link mechanism for locking, and performs the lock control by controlling the regulation force adjusting means. When stopping the operation of the first swing restriction mechanism, it is preferable to control the restriction force adjusting means so that the lock of the link mechanism is gradually released.

Thus, when the operation of the first swinging restricting mechanism is stopped, the restricting force for locking the link mechanism is gradually relaxed by controlling the restricting force adjusting means by the control means. Then, the lock of the link mechanism is gradually released. Therefore, when the lock of the link mechanism is released, a shock is less likely to occur in the vehicle body.

Next, as in the invention described in claim 19,
The turning change measuring means estimates the measured value of the yaw rate change rate or the lateral acceleration change rate by calculation using detection data of a plurality of detectors including a vehicle speed detector, and calculates the measured value. The calculation formula used for this purpose preferably includes a time differential term of the vehicle speed.

In this case, when the yaw rate change rate or the lateral acceleration change rate is estimated by the turning change measuring means by the calculation using the detection data of the plurality of detectors including the vehicle speed detector, A calculation formula including a differential term is used. Therefore, highly accurate measurement values can be obtained even when the vehicle speed changes when turning.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 A body swing control device for an industrial vehicle according to an embodiment of the present invention will be described with reference to FIGS. The vehicle body swing control device of this example is applied to a reach type forklift 1 (hereinafter referred to as a forklift) as an industrial vehicle as shown in FIGS.

The vehicle body rocking control device for the forklift 1 is designed so that the drive wheels 3 and the auxiliary wheels 4 arranged on the left and right sides of the vehicle body 1a allow the vehicle body 1a to rock in the roll direction. It is suspended via a link mechanism 20. The auxiliary wheel 4 is attached to the link mechanism 20 via a caster spring 30 which is an elastic member.

The vehicle body rocking control device has a first rocking regulating mechanism between the driving wheel 3 and the vehicle body 1a for locking the rocking of the driving wheel 3 and the link mechanism 20 with respect to the vehicle body 1a. . Further, a second swing restriction mechanism for locking the swing of the auxiliary wheel 4 with respect to the vehicle body 1a is provided between the auxiliary wheel 4 and the vehicle body 1a.

Further, the link mechanism 20 includes the vehicle body 1
It is attached to a via a suspension spring 32. The timing at which the second swing restriction mechanism operates is later than the timing at which the first swing restriction mechanism operates.

The vehicle body swing control device for the forklift 1 of this embodiment will be described in detail below. As shown in FIGS. 2 and 3, the forklift 1 is a three-wheel vehicle type having two front wheels and one rear wheel. The left and right front wheels 2 are driven wheels, and the rear one wheel is a driving wheel 3 that also serves as a steering wheel. The drive wheel 3 is offset to the left in the vehicle width direction, and an auxiliary wheel (caster wheel) 4 that is paired with the drive wheel 3 on the left and right is provided on the right side of the drive wheel 3.

The forklift 1 is a vehicle body (machine stand) 1a.
A mast 5 is provided on the front side. The mast 5 is movable in the front-rear direction along a pair of left and right reach legs 6 extending forward of the vehicle body 1a by driving a reach cylinder (not shown). The mast 5 includes an outer mast 7 and an inner mast 8. The inner mast 8 is driven by a lift cylinder 9 provided on the outer mast 7.
By moving up and down with respect to the outer mast 7, the lift bracket 10 moves up and down with a stroke about twice that. A fork 11 used as an attachment is tiltably attached to the lift bracket 10.

A main seat type cab 12 is provided on the right side of the rear portion of the vehicle body 1a. The steering wheel 1 is provided on the upper surface of the storage box 13 which is erected on the left side of the cab 12.
4 are provided. An instrument panel 15 on the front side of the operator's cab 12 is provided with an operation lever 16 for a cargo handling operation and an accelerator operation.

FIG. 4 shows the rear suspension structure of the forklift 1. A drive unit 17 having drive wheels 3 and a caster unit 18 having auxiliary wheels 4 are suspended from the rear portion of the vehicle body 1a so as to be vertically swingable with respect to a vehicle body frame 19 via a link mechanism 20.

The link mechanism 20 includes the upper link 2
1, a link 22, a lower link 23, and a caster link 24 are provided. The links 21 to 24 are connected by four shafts 25, 26, 27 and 28 located at the vertices of the quadrangle.

The upper link 21 extends substantially horizontally above the drive wheel 3, and its right end is rotatably connected to the vehicle body frame 19 by a fixed shaft 25. The lower link 23 is arranged to extend substantially horizontally obliquely below the upper link 21 and is rotatably connected to the vehicle body frame 19 by a fixed shaft 26 located near the center thereof.

The left end of the upper link 21 and the left end of the lower link 23 are connected to both ends of a substantially L-shaped link 22 extending substantially vertically by shafts 27 and 28, respectively, so as to be rotatable relative to each other.

The caster link 24 is arranged substantially horizontally to the right of the lower surface of the lower link 23, and the right end portion thereof is inserted into the guide shaft 29 attached to the right end portion of the lower link 23 so as to extend in the vertical direction. Is relatively displaceably connected to. On the other hand, the left end of the caster link 24 is rotatably connected to the fixed shaft 26.

A pair of front and rear caster springs 30 as elastic members are interposed between the lower link 23 and the caster link 24. The pair of auxiliary wheels 4 are supported by the caster link 24 in a rotatable state in a horizontal plane via a rotating mechanism (not shown).

The caster unit 18 is thus constructed. As shown in FIG. 5, each of the links 21 to 24 is formed in a substantially U-shape in a plan view having two arms facing each other with a predetermined distance in the front-rear direction. Are provided in a pair. In addition, drive unit 1
7 is configured as follows.

That is, the suspension spring 32 is interposed between the upper surface of the link 22 and the support member 31 fixed to the vehicle body frame 19, and the link 22 is moved downward by the suspension spring 32 with respect to the vehicle body frame 19. Being energized. Further, the shaft 27 connecting the upper link 21 and the link 22 is connected to the support base 34 to which the drive motor 33 is assembled.

The gear box 3 is provided below the support base 34.
A drive wheel 3 is rotatably supported on the lower portion of the gear box 35 so as to be rotatable relative to each other in a horizontal plane. As shown in FIG. 6, the gear wheel 36 fixed to the upper portion of the gear box 35 has a steering wheel 14
Is engaged with a gear portion 38 at the lower end of the steering shaft 37 that rotates in conjunction with the operation of the steering wheel 37, and the drive wheels 3 are steered according to the rotating operation of the steering wheel 14.

A gear box 40 having a motor 39 for power steering is arranged near the steering shaft 37, and the operating force is reduced by driving the motor 39 according to the operation of the steering wheel 14. . The steering wheel 14 and the steering shaft 37 are connected to each other by a shaft 41 that connects them.
Both ends of are connected by universal joints. The suspension spring 32 has the purpose of pressing the drive wheel 3 against the road surface to secure the ground pressure.

As shown in FIG. 4, one hydraulic damper 4 is provided between the support plate 42 extending horizontally from the support base 34 and the support member 43 extending horizontally from the vehicle body frame 19.
4 is installed. The damper 44 is composed of a double-acting hydraulic cylinder. The cylinder 44a of the damper 44 is connected to the support member 43 at its base end, and the piston rod 44b is connected to the support plate 42.

The cylinder 44a has a piston 4
Two pipelines 45 and 46 respectively communicating with the two chambers partitioned by 4c are connected, and both pipelines 45 and 46 are respectively connected to two ports of the electromagnetic switching valve 47. The electromagnetic switching valve 47 is a normally closed type 2-port 2-position switching valve that closes when demagnetized. Pipeline 4
An accumulator 49 that stores hydraulic oil is connected to the pipe 48 connected to the valve 6, and a check valve 50 is provided on the pipe 48 downstream of the accumulator 49. A throttle valve 51 is provided on the pipe line 46.

The damper 44 is provided with an electromagnetic switching valve 47.
When the spool is switched to the shut-off position shown in FIG. 4, the flow path for moving the hydraulic oil in the two chambers of the cylinder 44a is shut off, and the piston rod 44b is locked in a non-expandable state. Further, when the spool of the solenoid operated directional control valve 14 is switched to the communicating position (the position switched to the position opposite to the position shown in FIG. 4), the two chambers of the cylinder 44a are communicated with each other so that the hydraulic oil can move. The damper 44 is in a free (unlocked) state in which the piston rod 44b is allowed to expand and contract. The damper 44, the electromagnetic switching valve 47, and the like described above constitute a first swing restriction mechanism.

On the other hand, between the support plate 420 extending horizontally from the caster link 24 and the support member 430 extending horizontally from the vehicle body frame 19, one hydraulic damper 4 is provided.
40 is interposed. The damper 440 is the damper 44 described above.
It has the same structure as that of pipelines 450, 460, 48
0, the electromagnetic switching valve 470, the accumulator 490, and the check valve 500 throttle valve 510 constitute a second swing restriction mechanism. The second swing restricting mechanism has the same structure as the first swing restricting mechanism except the mounting position of the damper 440.

When the damper 44 is not locked, the link mechanism 20 works so that the ground pressure (wheel weight) between the drive wheel 3 and the auxiliary wheel 4 is distributed at the set ratio. For example, when the mast 5 moves forward and the position of the center of gravity moves to the front wheel 2 side, the link mechanism 20 moves so as to lower the drive wheel 3 relative to the vehicle body frame 19, and the drive wheel 3 receives a predetermined pressure or more. Ground pressure is secured. On the other hand, when the mast 5 moves backward and the center of gravity moves to the rear wheel side,
The link mechanism 20 moves so as to raise the drive wheels 3 relative to the vehicle body frame 19, and a part of the load is distributed to the auxiliary wheels 4 so that an excessive ground pressure is not applied to the drive wheels 3.

As shown in FIGS. 1 and 4, the gear wheel 3
A steering angle sensor 52 is provided in the vicinity of 6 as a steering angle detector that detects the rotation and outputs a detection signal necessary for obtaining the steering angle (tire angle) θ of the drive wheels 3. The steering angle sensor 52 includes, for example, a set of magnetic sensors capable of detecting rotation of the gear wheel 36 and outputting a detection signal having an amplitude number proportional to the rotation amount. Two types of detection signals having different phase differences are output so that they can be detected.

As the steering angle sensor 52, the drive wheels 3
Other detection method capable of detecting the steering angle θ of the vehicle may be used, for example, the motor 39 for power steering.
It is also possible to use a combination of a sensor for detecting the rotation of the steering wheel and a known sensor for detecting the rotation direction of the steering wheel 14 necessary for controlling the drive of the motor 39. A vehicle speed sensor 54 is provided above the drive motor 33 as a vehicle speed detector for indirectly detecting the vehicle speed V by detecting the rotation of the brake disc 53 that rotates integrally with the drive shaft.

Next, the electrical construction of the vehicle body swing control device provided in the forklift 1 will be described with reference to FIG.
The forklift 1 includes a controller 55 as a control means inside the housing box 13 (FIG. 3). The controller 55 is the microcomputer 5
6, A / D conversion circuits 57, 58 and excitation / demagnetization drive circuit 5
9 and so on.

The microcomputer 56 includes a central processing unit (hereinafter referred to as CPU) 60, a read-only memory (ROM) 61, a readable / writable memory (RAM) 62,
The counter 63, the input interface 64, and the output interface 65 are provided. The steering angle sensor 52, the vehicle speed sensor 54, and the CPU 60 constitute lateral acceleration measuring means and turning change measuring means. Also, the CPU 60
A lateral acceleration estimating means and a turning change rate estimating means are constituted by the above.

Further, the CPU 60 uses the steering angle sensor 5
2 and the vehicle speed sensor 54, the data of the steering angle θ and the vehicle speed V are acquired based on the respective detection signals input via the AD conversion circuits 57 and 58. Further, the solenoid 47a of the electromagnetic switching valve 47 is excited / demagnetized by turning on / off the excitation current output from the excitation / demagnetization drive circuit 59 based on the control signal output from the CPU 60.

That is, when the lock signal is commanded from the CPU 60, the current is no longer output from the excitation / demagnetization drive circuit 59, and the solenoid 47a is demagnetized, the electromagnetic switching valve 47 is activated.
Is switched to the cutoff position. Then, when the command of the lock signal is stopped from the CPU 60 and a current is output from the excitation / demagnetization drive circuit 59 to excite the solenoid 47a,
The electromagnetic switching valve 47 is switched to the communication position.

Although the operation based on the electrical configuration of the electromagnetic switching valve 47 in the first swing restriction mechanism has been described above, the same operation is performed for the electromagnetic switching valve 470 in the second swing restriction mechanism. .

The ROM 61 stores various program data including the program data for the swing control process shown in the flowcharts of FIGS. 11 to 13. Here, the swing control is to lock the damper 44 at a predetermined time when the centrifugal force during turning of the vehicle body 1a becomes large,
This is a control for increasing the stability of the vehicle body 1a in the left-right direction.

In this example, the lateral acceleration acting on the vehicle body 1a (centrifugal acceleration acting in the lateral direction of the vehicle body) G and the change rate (yaw rate change rate) ΔY / ΔT with respect to time of the yaw rate (turning angular velocity) Y when the vehicle turns. And are detected over time, and the first rocking regulation mechanism and the second rocking regulation mechanism are operated at the time when either one of the measured values of the lateral acceleration and the yaw rate change rate becomes equal to or more than the respective set value. Is set to.

As shown in FIG. 9A, two kinds of set values G ₁ and G ₂ are provided as set values of the lateral acceleration to the right when the vehicle turns left, and the set value G ₁ and the set value G ₂ are set. Have a difference. That is, the set value G ₂ is set to be larger than the set value G ₁ . Then, when the measured value of the lateral acceleration acting on the vehicle becomes the set value G ₁ or more, the first swing restricting mechanism is activated, and when the measured value becomes the set value G ₂ or more, the second swing restricting mechanism. Operate.

As a result, the vehicle turns left and the lateral acceleration G
_{After 1} operates and the first swing restriction mechanism operates, a larger lateral acceleration G ₂ acts and the caster spring 30 contracts to a predetermined length, so that the second swing restriction mechanism operates when the vehicle body further leans. To do. On the other hand, the set value G ₃ of the lateral acceleration at the time of turning right is set to a value larger than the set value G ₁ , and when the measured value becomes equal to or larger than the set value G _3, the first swing restriction mechanism is set. Activate.

The set values G ₁ and G ₃ are substantially equal to the inclination of the vehicle body 1a to the left when the lateral acceleration G ₃ is applied and the inclination of the vehicle body 1a to the right when the lateral acceleration G ₁ is applied. Is set to a value such that It should be noted that the second swing restriction mechanism is not operated during the right turn.

Further, as shown in FIG. 9B, the set value y ₀ of the set value of the yaw rate change rate ΔY / ΔT when the vehicle turns left is set, and the measured value of the yaw rate change rate ΔY / ΔT is set to the set value. When y ₀ or more, the first swing restriction mechanism is operated.

Note that the yaw rate change rate ΔY / ΔT is not considered as a parameter of the operating condition of the second rocking regulation mechanism. This is because the damper 440 is not locked until the caster spring 30 is contracted to a predetermined length to ensure a comfortable ride. On the other hand, when turning right, the yaw rate change rate ΔY / ΔT is not considered. This is to prevent the damper 44 from being locked until the suspension spring 32 contracts to a predetermined length.

Each set value G is stored in the ROM 61.₁, G₂，
G₃, Y₀The data of is stored. Each set value G₁，
G₂, G₃, Y₀The dampers 44 and 440 when necessary.
It is a value obtained from a running experiment so that the vehicle is locked. Well
In addition, the CPU 60 has four flags F_g, F _h, F_y, F_L
Is equipped with.

The flag F _g is set when the lateral acceleration Gs is equal to or greater than the set values G ₁ and G ₃ according to the turning direction, and is reset at other times. Also, the flag F _h is the lateral acceleration Gs is set when the set value G ₂ or more at the time of left turn, and is reset otherwise. Also, flag F
_y is set when the yaw rate change rate ΔY / ΔT is equal to or greater than the set value y ₀ during left turn, and is reset otherwise. Further, the lock flag _FL is set to the damper 44 (4
40) set in the lock, damper 44 (440)
Resets while unlocking.

In this example, the steering angle θ and the vehicle speed V obtained based on the detection signals of the steering angle sensor 52 and the vehicle speed sensor 54, respectively.
The lateral acceleration G and the yaw rate change rate ΔY / ΔT are estimated by the calculation using the above data. Lateral acceleration estimate G
s is expressed by the following equation (1) using the turning radius r determined from the steering angle θ.

Gs = V ² / r (1) Further, the yaw rate change rate ΔY / ΔT is expressed by the following equation (2) using two detection values θ and V.

ΔY / ΔT = V · (Δ (1 / r) / ΔT) (2) where r is the turning radius and Δ (1 / r) is the predetermined time of the reciprocal value 1 / r of the turning radius. It is the amount of change (deviation) per ΔT (for example, several tens of milliseconds). Deviation Δ (1 / r) is RA
Past a plurality of times and stored in M62 (a predetermined time [Delta] T min and once) from the steering angle data theta of, reads the steering angle data theta ₁ before a predetermined time [Delta] T, using the turning radius r ₁ that is determined from this data theta ₁ , Δ (1 / r) = | 1 / r−1 / r ₁ |.

By the way, the yaw rate change rate ΔY / ΔT
Is expressed by the following equation by differentiating the equation Y = V / r representing the yaw rate Y with respect to time. ΔY / ΔT = V · {Δ (1 / r) / ΔT} + (1 / r) · (ΔV / ΔT) (3) While the forklift 1 is turning, the vehicle speed V at time ΔT can be regarded as almost constant. Therefore, in this example, the equation (2) approximated by ignoring the latter term in the equation (3) is adopted as the arithmetic equation for estimating the ΔY / ΔT value.

Further, the ROM 61 stores the map MR shown in FIG. 8 for obtaining the turning radius r of the vehicle from the steering angle θ. In the present embodiment, the drive wheels 3 that are steering wheels
Considering that the vehicle is offset in the vehicle width direction, two types of map lines R and L for right turning and left turning are prepared to obtain the turning radius r from the steering angle θ.

For example, when the steering angle is θ = θ ₁ , the turning radius r _R is determined when the driving wheel 3 becomes the outer wheel and the turning radius r _R is determined, and the auxiliary wheel 4 is used.
When the vehicle turns to the left as an outer wheel, a turning radius r _{L that} is smaller than the r _R value when turning to the right is determined. Therefore, even if the method of calculating the measured value using the steering angle data θ is adopted, the lateral acceleration Gs
The estimated value of the yaw rate change rate ΔY / ΔT can be calculated correctly.

The lock release of the damper 44 is performed only when the lock condition is released (lock condition is not satisfied) for a predetermined time T. The duration of the lock condition release state is counted by the counter 63.

Next, the swing control process will be described with reference to FIG.
~ It demonstrates according to the flowchart of FIG. While the ignition key is on, the CPU 60 inputs detection signals from the sensors 52 and 54. The CPU 60 uses the sensors 52, 5
Steering angle θ and vehicle speed V obtained based on the detection signal from
The swing control process is executed at intervals of a predetermined time (for example, several tens of milliseconds) based on the above data.

First, the CPU 60 executes Step 10 (see FIG. 1).
S10 in FIG. 1, similarly S2 in FIGS.
0 to S270 represent Step 20 to Step 270), and the steering angle θ and the vehicle speed V which are detection data are read. In Step 20, the estimated lateral acceleration value Gs is calculated. That is, the map MR stored in the ROM 61
The turning radius r is calculated from the steering angle θ by using the equation (1), and the estimated lateral acceleration Gs is calculated from the vehicle speed V and the turning radius r using the equation (1).

At Step 30, the yaw rate change rate ΔY
Calculate / ΔT. That is, the steering angle data θ ₁ before a predetermined time ΔT is read from the predetermined storage area of the RAM 62, and the turning radius r ₁ determined from this data θ ₁ and the turning radius r determined from the current steering angle data θ are used to obtain Δ ( 1 / r) =
| 1 / r-1 / r 1 | and regarded, (2) from equation [Delta] Y / delta
Calculate T.

At Step 40, the current turning direction is judged. The turning direction is determined from the steering angle θ. When the turning angle is within the preset straight-ahead steering angle range, it is determined that the vehicle is going straight, when the steering angle is left, the vehicle makes a right turn, and when the steering angle is right, the vehicle makes a left turn. Step 50 when turning left
When the vehicle turns right, the process proceeds to Step 90, and when the vehicle goes straight, the routine ends.

When turning left, first in Step 50,
It is determined whether ΔY / ΔT is greater than or equal to the set value y ₀ .
If ΔY / ΔT ≧ y ₀ is satisfied, the process proceeds to Step 60 to set the flag F _y , and if ΔY / ΔT ≧ y ₀ is not satisfied, the process proceeds to Step 70 to reset the flag F _y .

At the next Step 80, it is judged if the lateral acceleration Gs is equal to or larger than the set value G ₂ . If Gs ≧ G ₂ is satisfied, the process proceeds to Step 100 to set the flag F _g , and if Gs ≧ G ₂ is not satisfied, the process proceeds to Step 110 to reset the flag F _g . When Gs ≧ G ₂ is satisfied, the lateral acceleration Gs is set to the set value G in Step 82.
Judge whether it is ₂ or more. If Gs ≧ G ₂ is established, the routine proceeds to Step 84, the flag F _h is set, and Gs
If ≧ G ₂ is not satisfied, the process proceeds to Step 86 and the flag F _h is reset.

When turning right, in Step 90, it is determined whether or not the lateral acceleration Gs is greater than or equal to the set value G ₃ . If Gs ≧ G ₃ is satisfied, the process proceeds to Step 100 to set the flag F _g , and if Gs ≧ G ₃ is not satisfied, the process proceeds to Step 110 to reset the flag F _g . In this way, the first swing restriction mechanism and the second swing restriction mechanism,
Also, the lock condition is different between right turn and left turn.
When turning right, the flags _Fh and _Fy are reset.

At Step 120, it is judged if at least one of the flags F _y and F _g is set. That is, it is determined whether or not the lock condition of the first swing restriction mechanism is satisfied (FIG. 12). If the lock condition is satisfied, the routine proceeds to Step 130, where the lock signal of the damper 44 is commanded. As a result, the spool of the electromagnetic switching valve 47 is switched to the shut-off position and the damper 44 is locked. On the other hand, the first
If the lock condition of the rocking | fluctuation control mechanism is not satisfied, Step14
Go to 0.

At Step 140, it is judged whether or not the switching is from lock to unlock. CPU60 lock flag F _L currently be in the unlock state if set, judges that the switching of Anrokkuhe from the lock. When the lock is switched to the unlock, the routine proceeds to Step 150, where the count value k of the counter 63 is incremented (k = k + 1). Counter 6
3 is reset, for example, when the damper 44 is switched from unlocked to locked. On the other hand, if the lock is not switched to the unlock, the process proceeds to Step 170.

At Step 160, it is judged whether or not the time counted by the counter 63 has passed a predetermined time T. That is, it is determined whether or not the lock condition is released (the flags F _g and F _y are both reset) for a predetermined time T. When it is determined that the predetermined time T has elapsed from the count value k of the counter 63, the process proceeds to Step 170. At Step 170, the command of the lock signal is stopped.

As a result, the spool of the electromagnetic switching valve 47 is switched to the communicating position, and the damper 44 is unlocked. When switching from lock to unlock in this way, the lock is not immediately released at the same time as the release of the lock condition, but the lock release of the damper 44 is executed after the lock condition release state continues for a predetermined time T. It

In the above Step 120,
When it is determined that either F _y or F _g is set and the lock signal output of the damper 44 is instructed in the above Step 130, the process proceeds to Step 220 and it is determined whether or not the flag F _h is set ( (Fig. 13). That is, it is determined whether or not the lock condition of the second rocking regulation mechanism is satisfied.

If the above lock condition is satisfied, Step 23
In step 0, the lock signal output of the second swing restriction mechanism is commanded. As a result, the damper 440 is locked. On the other hand, if the lock condition is not satisfied, the process proceeds to Step 240.
After proceeding to Step 240, a stop command of the lock signal output of the damper 440 is issued similarly to the case of the damper 44 described above. In addition, in FIG. 13, Step 24
0, 250, 260, 270 are each Step 14
It corresponds to 0, 150, 160, 170.

FIG. 14 is a graph showing changes in lateral acceleration Gs and yaw rate change rate ΔY / ΔT during turning. For example, as shown in FIG. 14A, when the vehicle makes a left turn from a straight line while traveling, the yaw rate change rate ΔY / ΔT exceeds the set value y ₀ before the lateral acceleration reaches the set value G ₁ , which leads to a faster movement. The damper 44 is locked. That is, the damper 44 is quickly locked almost at the same time when the turning is started.

Therefore, even if the vehicle is tilted to the right easily, as shown in FIG. 14B, the damper 44 is locked before the vehicle body 1a is largely tilted, and the link mechanism 20 is fixed to the vehicle body frame 19. To be done. After that,
As shown in (a), the lateral acceleration (Gs) exceeds the set value G ₁ until the yaw rate change rate ΔY / ΔT becomes less than the set value y ₀ after the steering angle θ has settled at a constant turning angle. The lock of the damper 44 is continued.

Thereafter, when the lateral acceleration Gs further increases, the caster spring 30 contracts and the vehicle body further tilts to the right. However, when the lateral acceleration Gs becomes equal to or greater than the set value G ₂ , the damper 440 of the second swing restriction mechanism is locked and the auxiliary wheel 4
Is fixed to the body frame 19. Therefore, during the left turn, the vehicle body 1a does not tilt significantly as shown in FIG. 15 (b).

Then, as shown in FIG. 14 (a), turn left
Turn right to the steering wheel (steering wheel) 14
Turning back and lateral acceleration Gs is G₂When less than,
The damper 440 is unlocked, and when turning right,
2 The swing control mechanism does not work and the damper 440 is unlocked.
Keep a state. Also, at this time, the lateral acceleration changes in that direction.
Set value G for a moment in the alternate section ₁Less than Only
However, since the turning direction is being changed, the yaw
Rate change rate ΔY / ΔT is set value y₀It takes the above value
Therefore, the operating condition of the first swing restriction mechanism continues, and the damper 44
The lock continues until it reaches a straight attitude. That
Then, when the vehicle turns straight after passing the straight attitude, the yaw rate is changed.
The rate of change ΔY / ΔT is used as a parameter for the lock control determination.
The damper 44 is unlocked because it is no longer used.
It

[0108] Then, when the vehicle 1a is left-tilted by the lateral acceleration of the left direction becomes the right turning, estimates Gs of lateral acceleration reaches a set value G _3, as shown in FIG. 15 (a) a damper 44 Is locked. Since the forklift 1 of this example is relatively hard to tilt to the left, as described above, the vehicle body 1a does not tilt significantly even if the locking of the link mechanism 20 is delayed, and vehicle stability does not pose a problem. .

On the other hand, as shown in FIG. 14 (b), when the vehicle turns straight ahead while traveling, the lateral acceleration Gs reaches the set value G ₃ as shown in FIG. 15 (a), and the damper 44 is turned on. Locked.

After that, the steering wheel 14 is turned from the right turn to the left turn.
When turning back, the damper 44 is unlocked when the lateral acceleration Gs becomes less than the set value G ₃ . Damper 44
Will be released after a predetermined time T from the time when the lock condition is released, but since it is an extremely short time, there is not much timing delay.

During the right turn, the yaw rate change rate ΔY / ΔT
Is not taken into account, so its value Δ in the turning process in the turning direction.
Even if Y / ΔT becomes equal to or greater than the set value y ₀ , the unlocked state of the damper 44 is continued until the vehicle takes the straight-ahead posture. If the yaw rate change rate ΔY / ΔT is already equal to or greater than the set value y ₀ when the vehicle makes a leftward turn after passing the straight-ahead posture, the vehicle body 1a is inclined before the vehicle body 1a tilts greatly when the leftward turn is started. The damper 44 is quickly locked.

The steering angle θ stabilizes at a constant turning angle and the yaw
Rate change rate ΔY / ΔT is set value y ₀Until less than
Then, the lateral acceleration Gs is the set value G₁As above, the damper 44
Will continue to be locked. After that, the lateral acceleration Gs is larger.
When it gets tight, the caster spring 30 contracts and the car body
Lean to the right. However, the lateral acceleration Gs is the set value G₂And above
Then, the damper 440 of the second rocking regulation mechanism is locked,
The auxiliary wheel 4 is fixed to the vehicle body frame 19. That
Therefore, the vehicle body 1a does not largely tilt during the left turn.

Next, the unlocking of the dampers 44, 440 is executed with a delay of a predetermined time T from the time when the respective locking conditions are not satisfied. Therefore, even if the flags F _y , F _g , and F _h are reset due to a slight timing difference between the changes in the ΔY / ΔT value and the Gs value during a right turn, the damper 44 or the damper 440 is locked. Continued. Further, even if the estimated value Gs of the lateral acceleration happens to fluctuate up and down at the set values G ₁ , G ₂ , and G ₃ during turning, the dampers 44 and 440 are still locked. Therefore, it is also possible to prevent unnecessary switching between locking and unlocking, which is caused by the fact that the estimated value Gs of the lateral acceleration happens to be a value near the set values G ₁ , G ₂ , and G ₃ .

As described in detail above, according to this embodiment, the following effects (1) to (7) can be obtained. (1) The vehicle body swing control device has the second swing control mechanism in addition to the first swing control mechanism. for that reason,
Even if the first rocking regulation mechanism operates and the damper 44 is locked, the second rocking regulation mechanism operates when the vehicle body 1a is still tilted and the tilt may impair the stability of the vehicle. The auxiliary wheel 4 and the vehicle body 1a can be locked. As a result, it is possible to solve the conventional problem that the vehicle 1a is tilted too much due to the presence of the caster spring 30 provided to improve the riding comfort. As described above, according to this example, it is possible to provide a vehicle body swing control device for an industrial vehicle that has a high vehicle body stability and a comfortable ride.

(2) Since the yaw rate change rate ΔY / ΔT is added to one of the parameters for determining whether or not the damper 44 should be locked, the damper 44 can be quickly locked at the start of the left turn, and the left turn is likely to occur. 1a due to the centrifugal force of
It is possible to prevent the inclination of the arrow from becoming too large.

Further, the yaw rate change rate ΔY / ΔT is not considered as a parameter for determining the lock control of the second rocking regulation mechanism and the lock control of the first rocking regulation mechanism at the time of turning right. The rocking restricting mechanism and the second rocking restricting mechanism, or the dampers 44, 44 during the right turn and the left turn.
It is easy to make a difference in the lock condition for locking 0.

(3) Since the lock release of the dampers 44, 440 is executed after the lock condition release state continues for the predetermined time T, unnecessary switching between lock and unlock can be prevented. For example, when the yaw rate change rate ΔY / ΔT becomes greater than or equal to the set value y ₀ and locks when the vehicle is turning to the left, the yaw rate change rate ΔY / ΔT is set to the set value due to a slight timing shift before the lateral acceleration Gs rises above the set value G _1. Both flags become less than y ₀ and both flags F _y , F
_{Even if g} is reset for a moment, the lock can be continued.

The estimated value Gs of the lateral acceleration during the turn is the set value G
_The damper 44 can be held in the locked state even when it fluctuates vertically at ₁ , G ₂ , and G _3, and the estimated lateral acceleration value Gs
It is possible to avoid frequent switching between locking and unlocking due to the fact that the value happens to be near the set values G ₁ , G ₂ and G ₃ .

(4) Since the lateral acceleration Gs and the yaw rate change rate ΔY / ΔT are calculated by using the respective detection data of the steering angle θ and the vehicle speed V, the acceleration sensor or the like which directly detects the lateral acceleration can be used. Eliminates the need for expensive detectors. In particular, if the vehicle speed sensor 54 originally attached to the forklift 1 can be used and the steering angle sensor 52 provided for other control or the like is used, the cost of the device can be relatively reduced by sharing the sensors. Can be suppressed to

(5) The lateral acceleration is estimated by the steering angle θ and the vehicle speed V.
Since the calculation is performed using each of the detection data, only the lateral acceleration Gs during turning can be estimated. Therefore, the estimated value Gs is not detected and the damper 4 is not detected even if the lateral acceleration occurs due to the left-right sway of the vehicle body 1a caused by the uneven road surface when traveling straight ahead.
4,440 is not locked. Therefore, the swing of the vehicle body 1a as described above is reliably absorbed.

(6) The map MR considering that the driving wheels 3 are offset in the vehicle width direction and the detection data of the steering angle θ is the same, but the turning radius r is different depending on the turning direction.
Since FIG. 8 is prepared, the estimated value Gs of the lateral acceleration and the yaw rate change rate ΔY / ΔT can be accurately obtained, and highly accurate swing control can be realized.

(7) The yaw rate change rate ΔY / ΔT is obtained by adding noise such as vibration of the vehicle body 1a to the detected value (lateral acceleration value) detected by the acceleration sensor, and performing a difference (differential) process on the noise. However, the noise is amplified by the difference processing, and the reliability of the estimated value ΔY / ΔT becomes poor. On the other hand, according to this example, the steering angle sensor 52
Since the value 1 / r obtained from the steering angle data θ that is less likely to be affected by the vibration or the like of the vehicle body 1a detected by is subtracted (differentiated), the highly reliable estimated value ΔY / ΔT can be obtained.

Embodiment 2 In this embodiment, as shown in FIGS. 16 and 17, the acceleration sensor 7
0 and the vehicle speed sensor 54 are used to detect the lateral acceleration directly and to estimate the yaw rate change rate ΔY / ΔT from the detected data of the lateral acceleration and the vehicle speed. is there. The configuration is the same as that of the first embodiment except that the combination of the sensors used for the swing control is changed, and therefore the same members are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 16, the acceleration sensor 70 serving as the turning change measuring means is provided in the housing box 1 at the rear of the vehicle body.
It is attached in the vicinity of the vehicle width center in 3 and is arranged in a posture capable of detecting the lateral acceleration of the vehicle body 1a. As shown in FIG. 17, the vehicle speed sensor 54 detects the rotation of the brake disc 53 as in the first embodiment. The acceleration sensor 70 and the vehicle speed sensor 54 are electrically connected to the controller 55.

The CPU 60 in the controller 55 is
The lateral acceleration Gr is obtained from the detection value of the acceleration sensor 70, and the yaw rate change rate ΔY / ΔT is estimated by calculation using the vehicle speed data V and the lateral acceleration data Gr obtained from the detection signal of the vehicle speed sensor 54. In addition, CPU6
0, the acceleration sensor 70 and the vehicle speed sensor 54 constitute a turning direction determining means.

The yaw rate change rate ΔY / ΔT is given by the following (4)
It is calculated by a formula. ΔY / ΔT = (ΔG / ΔT) · (1 / V) (4) Here, ΔG / ΔT is the lateral acceleration data stored in the RAM 62 for a plurality of past times (one predetermined time ΔT). , The lateral acceleration data Gr ₁ before the predetermined time ΔT is read out, and ΔG / ΔT is read using the current lateral acceleration data Gr.
= | Gr−Gr ₁ |.

In the swing control processing executed by the CPU 60, the detection data of the lateral acceleration Gr and the vehicle speed V is read in step 10 shown in FIG. Step 20
The calculation of Gs is omitted, and in step 30, the yaw rate change rate ΔY / ΔT is calculated using the equation (4). In step 40, the turning direction is determined based on whether the value detected by the acceleration sensor 70 is positive or negative.

Therefore, according to this example, the first embodiment described above is used.
The effects of (1) to (3) described in (4) are similarly obtained. Further, since the lateral acceleration during straight running is detected, when the vehicle body 1a sways to the left or right due to the unevenness of the road surface, the damper 44 is locked and the swaying to the left and right becomes difficult to be absorbed.
Even when traveling straight ahead, for example, when traveling on a road surface inclined to the left or right, the damper 44 is locked when the lateral acceleration Gr exceeds the set values G ₁ and G _3, and the damper 440 is locked when the lateral acceleration Gr exceeds the set value G _2. Therefore, the left and right stability of the vehicle body 1a can be ensured. Further, as the vehicle speed sensor 54, one originally attached to the forklift 1 can be used.

Embodiment 3 As shown in FIGS. 18 and 19, this embodiment uses a yaw rate sensor 71 and a vehicle speed sensor 54, and estimates the lateral acceleration and the yaw rate change rate ΔY / ΔT using these detected values. It is an example of a vehicle body swing control device of the forklift 1 configured to obtain a value. Since the configuration is the same as that of the first embodiment except that the combination of the sensors used for the swing control is changed, the same members are designated by the same reference numerals and description thereof will be omitted.

As shown in FIG. 18, a yaw rate sensor (gyroscope) 71 as a yaw rate detector is
It is mounted in the storage box 13 at the rear of the vehicle body near the center of the vehicle width. In this example, as the yaw rate sensor 71, a piezoelectric gyroscope including a piezoelectric element is used. As another method, for example, a gas rate gyroscope or an optical gyroscope can be used. As shown in FIG. 19, the vehicle body swing control device of this example includes a vehicle speed sensor 54 as a vehicle speed detector that detects the rotation of the brake disc 53, as in the first embodiment.

As shown in FIG. 19, the yaw rate sensor 7
1 and the vehicle speed sensor 54 are electrically connected to a controller 55 as a control means. The CPU 60 in the controller 55 includes a yaw rate sensor 71 and a vehicle speed sensor 54.
Using the data of the yaw rate Y and the vehicle speed V obtained from the respective detected values, the lateral acceleration Gs and the yaw rate change rate ΔY / ΔT
And estimate. The CPU 60 and the yaw rate sensor 7
1 and the vehicle speed sensor 54 constitute a lateral acceleration measuring means and a turning change measuring means, and the CPU 60 constitutes a lateral acceleration estimating means and a turning change rate estimating means.

The estimated lateral acceleration value Gs is calculated by the following equation (5). Gs = Y−V (5) Further, the yaw rate change rate ΔY / ΔT is the yaw rate data Y before the predetermined time ΔT from the past plural times yaw rate data stored in the RAM 62 (the predetermined time ΔT is one time). ₁ is read out, and using the current yaw rate data Y, ΔY / ΔT = | Y−Y ₁ |

In the swing control process executed by the CPU 60, the detection data of the yaw rate Y and the vehicle speed V is read in step 10 shown in FIG. Step 20
Then, the estimated value Gs of the lateral acceleration is calculated using the above equation (5). In step 30, the expression ΔY / ΔT = | Y
The yaw rate change rate ΔY / ΔT is calculated from −Y ₁ |. In step 40, the turning direction is determined based on whether the detected value of the yaw rate sensor 71 is positive or negative.

Therefore, according to this example, the effects (1) to (3), (5), and (6) described in the first embodiment can be similarly obtained. Further, the vehicle speed sensor 54 that is originally attached to the forklift 1 can be used. It should be noted that the detected value of the yaw rate sensor 71 is unlikely to include noise due to vibration of the vehicle body 1a, and there is no concern about amplification of noise even if the difference processing is performed, so a highly reliable estimated value ΔY / ΔT can be obtained.

Fourth Embodiment As shown in FIGS. 20 and 21, this embodiment has a configuration in which an acceleration sensor 70 and a vehicle speed sensor 54 are used as in the second embodiment, but only lateral acceleration during turning is selected. The second embodiment is different from the second embodiment in that it is obtained. Since the configuration is the same as that of the first embodiment except that the sensor used for swing control is changed, the same members are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 20, one acceleration sensor 70 as a lateral acceleration measuring means is attached near the center of the vehicle width in the accommodation box 13 at the rear of the vehicle body, and the reach leg 6 on one side (for example, the left side in this example) is attached. One acceleration sensor 72 is attached slightly to the front. The two acceleration sensors 70, 72 are respectively arranged in a posture capable of detecting lateral acceleration with respect to the vehicle body 1a. Further, as shown in FIG. 21, a vehicle speed sensor 54 as a vehicle speed detector for detecting the rotation of the brake disc 53 is provided as in the second embodiment.

As shown in FIG. 21, two acceleration sensors 70 and 72 and one vehicle speed sensor 54 are electrically connected to the controller 55. The CPU 60 in the controller 55 obtains the lateral accelerations Gar and GBr from the detection values of the two acceleration sensors 70 and 72, and the vehicle speed V obtained from the detection signal of the vehicle speed sensor 54 and the rear acceleration sensor 70, for example. The yaw rate change rate ΔY / ΔT is estimated by calculation using the detected lateral acceleration Gar. The CPU 60, the acceleration sensor 70, and the vehicle speed sensor 5
The turn change measuring means is constituted by 4. Also, CP
The U60 and the two acceleration sensors 70 and 72 constitute a turn determination means.

The yaw rate change rate ΔY / ΔT is calculated by using the above equation (4): ΔY / ΔT = (ΔG / ΔT)  (1
/ V). Where ΔG / ΔT is RA
The lateral acceleration data GAr ₁ before the predetermined time ΔT is read from the lateral acceleration data of the past multiple times (one time for the predetermined time ΔT) stored in M62, and the present lateral acceleration data GAr
Using DOO, ΔG / ΔT = | GAr- GAr 1 | is calculated by.

In the swing control processing executed by the CPU 60, in step 10 shown in FIG. 11, the detection data of the lateral accelerations Gar, GBr and the vehicle speed V are read. The calculation of Gs in step 20 is omitted, and in step 30, the yaw rate change rate ΔY / ΔT is calculated using the equation (4).
Is calculated. In step 40, lateral accelerations GAr and GBr
Difference δ = | GAr−GBr | is obtained. When the difference δ is equal to or greater than a preset value δ ₀ (δ ≧ δ ₀ ), it is determined that the vehicle is turning, and when δ ≧ δ ₀ , the acceleration sensor The turning direction is determined by the positive or negative of the detection value Gar of.

In other words, the acceleration sensors 70 and 72 are arranged at two locations on the vehicle body where the turning radii during turning will be different, and the detected values of the acceleration sensors 70 and 72 will differ by more than a certain value. When the vehicle is turned on, it is determined that the vehicle is turning. For example, the acceleration sensors 70, 7
If the detection value GAr of 2 has a positive value when turning to the right and a negative value when turning to the left, δ ≧ δ ₀ and GA
When r> 0, it is determined that the vehicle is turning right, when δ ≧ δ ₀ and GAr <0, it is determined that the vehicle is turning left, and when δ <δ ₀ , it is determined that the vehicle is traveling straight.

As shown in the flowchart of FIG. 11, the swing control process is performed by the dampers 44, 44 when the vehicle goes straight.
Don't lock 0. On the other hand, similarly to the second embodiment, when the lateral acceleration is detected even when the vehicle is traveling straight, the damper 44 is used when the detected value Gar is equal to or more than the set values G ₁ and G ₃ , and the damper is used when the detected value Gar is equal to or more than the set value G _2. 440 is locked so that, depending on the direction of the lateral acceleration Gar, when the direction is left, the set value G ₃ for right turn is used, and when the direction is right, the set value for left turn is used. it may be use G _1, G _2.

In the case of the former, the vehicle body 1a may be damaged by the unevenness of the road surface.
Swaying to the left and right, the damper 44 is not locked even when the lateral acceleration Gar becomes equal to or greater than the set values G ₁ and G ₃ , or the damper 440 is not locked even when the lateral acceleration becomes equal to or greater than the set value G ₂ , and the sway can be reliably absorbed. . In the latter case, if the lateral acceleration Gar is equal to or greater than the set values G ₁ and G ₃ even when traveling straight, the damper 44 is
Alternatively, the damper 440 is locked when the set value exceeds G ₂ . Therefore, for example, when traveling straight on a road surface inclined to the left and right, the left and right stability of the vehicle body 1a can be ensured.
In addition, according to this example, (1) to (1) described in the first embodiment
The effect of (3) is similarly obtained.

Embodiment 5 In this embodiment, as shown in FIG. 22, the electromagnetic proportional valve 75 is used in place of the electromagnetic switching valve 47 to adjust the opening thereof, and the above-mentioned Embodiments 1 to 4 are adopted. Different from It should be noted that, except that the electromagnetic switching valve used for swing control is changed to an electromagnetic proportional valve, the configuration is the same as that of the first embodiment, so the same members are given the same reference numerals and description thereof is omitted. Further, the electromagnetic switching valve 470 in the second swing restriction mechanism is also changed to an electromagnetic proportional valve similar to the electromagnetic proportional valve 75. The solenoid proportional valve 75 will be described below.

As shown in FIG. 22, the two conduits 45 and 46 connected to the cylinder 44a of the damper 44 are connected to the two ports of the solenoid proportional valve 75 as the regulating force adjusting means. The CPU 60 in the controller 55 controls the current flowing through the solenoid 75a of the solenoid proportional valve 75 by, for example, duty value control, and adjusts the opening of the solenoid proportional valve 75. It should be noted that the damper 44, the solenoid proportional valve 75, and the like constitute a swing restriction mechanism.

As shown in FIG. 23, when the lock condition is satisfied, the CPU 60 outputs a lock signal to output the solenoid 75a.
Immediately reduce the current to the solenoid proportional valve 75 and fully open it. Further, when the lock condition is released, the CPU 60 stops the output of the lock signal and gradually increases the current to the solenoid 75a to gradually open the opening of the solenoid proportional valve 75 from the fully closed to the fully opened at a substantially constant rate. Is set.

Therefore, according to this embodiment, when the lock of the damper 44 is released, the electromagnetic proportional valve 75 is gradually opened from the fully closed to the fully opened, so that the vehicle body 1a is released when the link mechanism 20 is unlocked. Shock is unlikely to occur. Therefore, for example, even if the vehicle body 1a is unlocked during turning, it is possible to prevent the vehicle body 1a from becoming unstable due to a shock at the time of unlocking.

Embodiment 6 As shown in FIGS. 24 and 25, this embodiment is different from the above embodiments in that the set value used for swing control is different when the damper 44 is locked and when it is unlocked. Different from the form example. It should be noted that the configuration is the same as that of the first embodiment except that the content of the swing control is partially changed.

As shown in FIG. 24, as a set value for ΔY / ΔT, “y ₀ ” is used when the damper 44 is locked (when the flag F _y is set), and the damper 44 is unlocked. when little smaller set value than "y _0" (when the flag F _y is reset) "alpha · y _0" (for example,
0.5 <α <1) is used.

Further, as shown in FIG. 25, as the set value for Gs, when locking the damper 44 (when the flag F _g is set), “G ₁ ” and “G ₃ ” are used, and the damper 44 When releasing the lock of (when the flag _Fg is reset), the set value "α ・" which is a little smaller than "G ₁ " and "G ₃ "
G ₁ ”and“ α · G ₃ ”(for example, 0.5 <α <1) are used.

Therefore, once the damper 44 is locked, α which is slightly smaller than the set value at that time (for example, 0 <
The lock is not released until it falls below the set value of α <1) times. Therefore, for example, the yaw rate change rate ΔY / ΔT
It is possible to prevent the occurrence of frequent switching between locking and unlocking due to the occurrence of a value near the set value y ₀ or the lateral acceleration Gs happening to reach a value near the set values G ₁ and G _3. It Therefore, the lock control of the damper 44 can be stably performed. The above settings can also be applied to the conditions for locking and unlocking the damper 440.

Embodiment 7 This example is an example in which a calculation formula that takes into account the time difference term (time differential term) of the vehicle speed V is used in the calculation of the yaw rate change rate.
In the first embodiment, the second embodiment, the fourth embodiment, and the like for calculating the yaw rate change rate ΔY / ΔT, the vehicle speed V is regarded as constant and the time difference term (time derivative term) of the vehicle speed V is ignored. Used a formula.

On the other hand, in this example, a calculation formula considering the time difference term (time differential term) of the vehicle speed V is used. The configuration is the same as in the first and third embodiments, etc., except that the calculation formula of the yaw rate change rate ΔY / ΔT is different. First, the steering angle sensor 52 and the vehicle speed sensor 5
In the configuration of the first embodiment and the like using No. 4, instead of the above equation (2) used in the first embodiment, for example, the equation (3) described above in which the time difference term of the vehicle speed V is considered is calculated. To use as. In other words, it is the following formula.

ΔY / ΔT = V− (Δ (1 / r) / ΔT) + (1 / r) · (ΔV / ΔT) (3) Here, ΔV / ΔT is the predetermined time ΔT (of the vehicle speed V For example, it is a change amount (deviation) per several tens of milliseconds. ΔV /
ΔT is a predetermined time Δ from the vehicle speed data V stored in the RAM 62 for a plurality of past times (one time is a predetermined time ΔT).
The vehicle speed data V ₁ before T is read and ΔV / ΔT = | V−V ₁
Calculate with |.

Also, the following equation can be adopted. ΔY / ΔT = Δ (V / r) / ΔT (6) where Δ (V / r) / ΔT is the calculated value V of the yaw rate.
/ R is a variation (deviation) per predetermined time ΔT (for example, several tens of milliseconds). Δ (V / r) / ΔT is RAM6
The yaw rate data V ₁ / r ₁ before the predetermined time ΔT is read from the yaw rate data V / r for the past multiple times (one time for the predetermined time ΔT) stored in 2, and Δ (V / r) / Δ
T = | V / r-V 1 / r 1 | by calculating.

Further, the acceleration sensor 70 and the vehicle speed sensor 54
The following equations are used in the configurations of Embodiment 2 and Embodiment 4 using ΔY / ΔT = (ΔG / ΔT) · (1 / V) + G · (Δ (1 / V) / ΔT) (7) where Δ (1 / V) / ΔT is the reciprocal of the vehicle speed 1 / It is a variation (deviation) of V per predetermined time ΔT (for example, several tens of milliseconds). From the vehicle speed data V stored in the RAM 62 for a plurality of past times (one time for a predetermined time ΔT),
The vehicle speed data V ₁ before the predetermined time ΔT is read, and using the current vehicle speed data V, Δ (1 / V) / ΔT = | 1 / V−
It is calculated by 1 / V ₁ |.

Also, the following equation can be adopted. ΔY / ΔT = Δ (G / V) / ΔT (8) where Δ (G / V) / ΔT is the calculated yaw rate value G
/ V is a variation (deviation) per predetermined time ΔT (for example, several tens of milliseconds). Δ (G / V) / ΔT is RAM6
The yaw rate data G ₀ / V ₁ before the predetermined time ΔT is read from the yaw rate data G / V for the past multiple times (one time for the predetermined time ΔT) stored in 2, and Δ (G / V) / Δ
It is calculated by T = | G / V−G ₀ / V ₁ |.

According to the configuration adopting the calculation formula in consideration of the time difference term of the vehicle speed V, it is possible to obtain the yaw rate change rate ΔY / ΔT with high accuracy even when the vehicle speed changes, so that the vehicle speed change is accompanied. Even when the vehicle turns, the damper 44 can be locked at an appropriate time.

Eighth Embodiment This example is an example in which a lateral acceleration change rate ΔG / ΔT is adopted instead of the yaw rate change rate ΔY / ΔT used in each of the above-described embodiments. First, the steering angle sensor 52 and the vehicle speed sensor 5
In the configuration of the first embodiment and the like using No. 4, the following equation is used as the equation for calculating the lateral acceleration change rate ΔG / ΔT.

ΔG / ΔT = V ² · Δ (1 / r) / ΔT (9) where Δ (1 / r) / ΔT is the reciprocal value 1 / r of the turning radius determined from the steering angle data θ. It is a change amount (deviation) per predetermined time ΔT (for example, several tens of milliseconds). Δ (1 /
r) / ΔT is the current data 1 / r obtained by reading the data 1 / r ₁ before the predetermined time ΔT out of the data stored in the RAM 62 for the past multiple times (one time for the predetermined time ΔT).
Using and, Δ (1 / r) / ΔT = | 1 / r−1 / r ₁ |
Calculate by

In the swing control process executed by the CPU 60, in step 30 shown in FIG. 11, the lateral acceleration change rate ΔG / ΔT is calculated using the equation (9). Then, in step 50, the lateral acceleration change rate Δ
G / ΔT is not less than the set value g ₀ (ΔG / ΔT ≧
g ₀ ) or not.

The time difference term of the vehicle speed V (time derivative term)
Instead of the above equation (9) ignoring the above, a calculation equation considering the time difference term of the vehicle speed V can be adopted. For example, one of the following two formulas can be adopted.

ΔG / ΔT = V ² · Δ (1 / r) / ΔT + (1 / r) · 2V · ΔV / ΔT ... (10) ΔG / ΔT = Δ (V ² /r)/ΔT...(11) Here, Δ (V ² / r) / ΔT in the equation (11) is a change amount (deviation) of the lateral acceleration data Gs (= V ² / r) per predetermined time ΔT (for example, several tens of milliseconds). is there. Δ (V
² / r) / ΔT is the lateral acceleration data Gs ₁ read a predetermined time ΔT before from the lateral acceleration data stored in the RAM 62 for a plurality of past times (assuming that the predetermined time ΔT is one time), and the current lateral acceleration data Gs Using and, Δ (V ² / r) / ΔT
= | Gs−Gs ₁ |

Further, the acceleration sensor 70 and the vehicle speed sensor 54
When the lateral acceleration change rate ΔG / ΔT is adopted in the configurations of Embodiment 2 and Embodiment 4 that use
The ΔG / ΔT value is calculated from the change amount (deviation) of the lateral acceleration data Gr per predetermined time ΔT (for example, several tens of milliseconds). As ΔG / ΔT, the lateral acceleration data Gr ₁ before the predetermined time ΔT is read from the past multiple times of lateral acceleration data stored in the RAM 62 (the predetermined time ΔT is one time), and the current lateral acceleration data Gr is used. , ΔG / ΔT = | Gr−
It is calculated by Gr ₁ |.

In the configuration of the second embodiment and the like using the yaw rate sensor 72 and the vehicle speed sensor 54, the following equation is used as the equation for calculating the lateral acceleration change rate ΔG / ΔT. ΔG / ΔT = V · ΔY / ΔT (12) Further, instead of the above formula (12) in which the time difference term (time differential term) of the vehicle speed V is ignored, a calculation formula considering the time difference term of the vehicle speed V is adopted. You can also For example, one of the following two formulas can be adopted.

ΔG / ΔT = V−ΔY / ΔT + Y · ΔV / ΔT (13) ΔG / ΔT = Δ (V · Y) / ΔT (14) Here, Δ (V · Y in the equation (14) ) / ΔT is a predetermined time ΔT of the lateral acceleration data Gs (= V · Y) (for example, Equation 1).
It is the amount of change (deviation) per 0 millisecond. Δ (V ・
Y) / ΔT is obtained by reading out lateral acceleration data Gs ₁ before a predetermined time ΔT from lateral acceleration data stored in the RAM 62 for a plurality of past times (assuming that the predetermined time ΔT is one time), and calculating the current lateral acceleration data Gs. Use, Δ (V ・ Y) / ΔT = | G
It is calculated by s-Gs ₁ |.

As described above, the yaw rate change rate ΔY / ΔT
Alternatively, in the configuration in which the lateral acceleration change rate ΔG / ΔT is used as one of the lock control determination parameters, Δ
By locking the damper 44 when G / ΔT ≧ g ₀ is satisfied, the link mechanism 20 is quickly locked at the start of the left turn, and the right tilt angle due to the centrifugal force during the left turn of the vehicle body 1a is prevented from becoming too large. be able to.

Further, as a calculation formula for calculating the lateral acceleration change rate ΔG / ΔT, if a calculation formula considering the time difference term (time differential term) of the vehicle speed V is used, when the vehicle speed changes when turning, However, the lateral acceleration change rate ΔG / Δ with high accuracy
After obtaining T, the damper 44 can be locked at an appropriate time. In addition, the same effects as those obtained in the respective corresponding embodiments can be obtained.

When the detected value of the acceleration sensor 70 is subjected to the difference processing (differential processing), it is desirable to filter the detected value in advance to remove noise. As the filtering process, for example, there is a method of averaging the detection data of the past multiple times. It is more preferable to perform the same filtering process on the detection data other than the lateral acceleration, because more accurate detection data can be obtained.

The embodiment of the present invention is not limited to the above, but can be modified as follows. First, it is not always necessary to use the yaw rate change rate ΔY / ΔT and the lateral acceleration change rate ΔG / ΔT as parameters for determining the swing control (lock control). That is, a configuration may be used in which only the lateral acceleration is used as a parameter for the lock control determination. Even with this configuration, the stability of the vehicle body 1a can be ensured.

Secondly, in the fourth embodiment, instead of using the two acceleration sensors 70 and 72, one acceleration sensor and a steering angle sensor or a yaw rate sensor as a turning determination means are used, and steering is performed. It may be possible to determine whether or not the vehicle is turning based on the data of the angle θ or the yaw rate Y.

Thirdly, in each of the above embodiments, a sensor is provided for detecting that the suspension spring 32 has expanded or contracted to a predetermined length, and the damper 44 is locked only when the sensor detects it. You may do it. Further, a similar sensor may be provided for the caster spring 30 and the damper 440 may be similarly locked and controlled. According to this structure, even if the lateral acceleration value detected during turning varies, when the suspension spring 32 (caster spring 30) is extended or contracted to a predetermined length, the damper 44 (damper 44
0) can be locked.

Fourthly, the first swing restricting mechanism is the damper 44 interposed between the link mechanism 20 and the body frame 19.
And an electromagnetic switching valve 47 (or an electromagnetic proportional valve 75) for controlling the lock of the damper 44, and the like. For example, a swinging restricting mechanism is composed of a stopper provided in a gap between the link mechanism and the vehicle body frame so as to be able to move forward and backward, and an actuator for moving the stopper forward and backward. It is also possible to adopt a method of locking.

The stoppers are brought into contact with the link mechanism at two points so that the movement of the link mechanism 20 in either direction can be restricted. Further, the contact surface where the stopper abuts on the link mechanism 20 is formed into a taper inclined in the entering direction, and the stopper is slowly retracted, whereby the link mechanism 2 is moved.
The 0 lock may be gradually released. In addition, the second swing control mechanism also includes the auxiliary wheel 4 and the vehicle body frame 19
It is not limited to the configuration including the damper 440 interposed between the damper 440 and the electromagnetic switching valve 470 (or the electromagnetic proportional valve) for controlling the lock of the damper 440.

Fifth, the auxiliary wheel 4 that makes a pair with the drive wheel 3 in the vehicle width (left-right) direction is not limited to a caster wheel that can simply rotate horizontally. For example, it may be a steered wheel that makes a pair with the drive wheel 3 on the left and right and is steered together. Also in this case,
It is possible to ensure the stability of the vehicle body 1a.

Sixthly, in each of the above embodiments, the lift sensor for detecting the lift of the fork 11 and the fork 11 are used.
A load sensor for detecting the weight of the upper load is provided, and when the load is loaded by these sensors, the position of the center of gravity of a vehicle at a high lift is detected to be relatively high, and the position of the center of gravity is higher than a predetermined value. In the state, the link mechanism 20 or the configuration in which the link mechanism 20 and the auxiliary wheel 4 are locked can be adopted.

Seventhly, the set value of the lateral acceleration or the yaw rate change rate is intermittently or continuously changed so as to become smaller as the position of the center of gravity is set, depending on the position of the center of gravity determined from the detection values of the above-mentioned sensors. However, it can be configured to further secure the left and right stability of the vehicle body in consideration of the position of the center of gravity of the vehicle.

Eighth, the method of measuring the lateral acceleration and the yaw rate change rate or the lateral acceleration change rate is not limited to the method of each of the above embodiments, and an appropriate method can be adopted. For example, a method may be adopted in which the lateral acceleration is indirectly derived from the lateral tilt angle of the vehicle body 1a detected by the tilt angle sensor. Further, a steering wheel angle sensor that detects the rotation angle of the steering wheel 14 can be used as a steering angle detector.

Ninth, the locking of the link mechanism 20 is not limited to completely fixing the link mechanism 20 to the vehicle body frame 19, and even if the movement range of the link mechanism 20 with respect to the vehicle body 1a is restricted to a narrow range. I do not care. A uniform effect can be obtained if the swing range of the drive wheel 3 and the driven wheel 4 is kept small.

In the above embodiment, the reach type forklift is explained as an example, but the present invention is not limited to such a vehicle body swing control device of the reach type forklift.

[0180]

As described above, according to the present invention, it is possible to provide a vehicle body swinging control device for an industrial vehicle having a high vehicle body stability and a comfortable riding comfort.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a vehicle body swing control device according to a first embodiment.

FIG. 2 is a side view of the reach type forklift according to the first embodiment.

FIG. 3 is a plan view of the reach type forklift according to the first embodiment.

FIG. 4 is an explanatory rear view showing the vehicle body swing control device according to the first embodiment.

FIG. 5 is a plan view showing a rear suspension structure according to the first embodiment.

FIG. 6 is a rear view showing a part of the rear suspension structure according to the first embodiment.

FIG. 7 is a block diagram showing an electrical configuration of a vehicle body swing control device according to the first embodiment.

FIG. 8 is a map diagram showing a relationship between a steering angle and a turning radius in the first embodiment.

FIG. 9 (a) Lateral acceleration in the first embodiment,
(B) A graph showing each lock condition of the yaw rate change rate.

FIG. 10 is a timing chart when stopping a command of a lock signal in the first embodiment.

FIG. 11 is a flowchart of swing control processing according to the first embodiment.

FIG. 12 is a flowchart continued from FIG. 11;

FIG. 13 is a flowchart continued from FIG. 12;

FIG. 14 is a diagram for explaining swing control during turning of the vehicle in the first embodiment.

FIG. 15 is a rear view showing (a) the link mechanism locked when turning to the right and (b) the link mechanism locking simultaneously to the left in the first embodiment.

FIG. 16 is a plan view showing a reach type forklift according to a second embodiment.

FIG. 17 is an explanatory diagram of a vehicle body swing control device according to the second embodiment.

FIG. 18 is a plan view showing a reach type forklift according to a third embodiment.

FIG. 19 is an explanatory diagram of a vehicle body swing control device according to the third embodiment.

FIG. 20 is a plan view showing a reach type forklift according to a fourth embodiment.

FIG. 21 is an explanatory diagram of a vehicle body swing control device according to the fourth embodiment.

FIG. 22 is a partial explanatory view of the vehicle body rocking control device according to the fifth embodiment.

FIG. 23 is a timing chart when stopping a lock signal command in the fifth embodiment.

FIG. 24 is a diagram showing the conditions for locking and unlocking the yaw rate change rate in the sixth embodiment.

FIG. 25 is a lateral acceleration lock according to the sixth embodiment;
A diagram showing conditions for unlocking.

[Explanation of symbols]

1. ． ． Reach-type forklift, 1a. ． ． Car body, 19. ． ． Body frame, 20. ． ． Link mechanism, 3. ． ． Drive wheel, 30. ． ． Castor spring, 32. ． ． Suspension springs, 4. ． ． Auxiliary wheels, 44, 440. ． ． Damper, 47, 447. ． ． Electromagnetic switching valve, 52. ． ． Steering angle sensor, 54. ． ． Vehicle speed sensor, 55. ． ． Controller, 60. ． ． Central processing unit (CPU), 70. ． ． Acceleration sensor, 71. ． ． Yaw rate sensor, 72. ． ． Acceleration sensor, 75. ． ． Solenoid proportional valve, Gs, Gr. ． ． Lateral acceleration, ΔY / ΔT ... Yaw rate change rate, ΔG / ΔT. ． ． Lateral acceleration change rate, G ₁ , G ₂ , G ₃ . ． ． Setting value, y ₀ . ． ． Set value, g ₀ . ． ． Set value,

Continued front page    F-term (reference) 3D001 AA03 AA13 CA09 DA02 DA14                       DA17 EA00 EA02 EA08 EA22                       EA36 EA42 EB00 EB08 EC00                       EC02 EC05 EC07 ED02 ED05                       ED16                 3F333 AA02 AB13 BE02 CA12 CA17                       DB02 FA20 FE03 FE09 FH08

Claims (19)

[Claims] 1. A drive wheel and an auxiliary wheel disposed on the left and right of a vehicle body of an industrial vehicle are suspended from the vehicle body via a link mechanism so as to allow the vehicle body to swing in a roll direction. An auxiliary wheel is attached to the link mechanism via an elastic member. In a vehicle body swing control device for controlling vehicle body swing, the vehicle body swing control device is configured to connect the drive wheel and the vehicle body. A first swing restriction mechanism for locking the swing of the drive wheel and the link mechanism with respect to the vehicle body is provided between them, and a swing of the auxiliary wheel with respect to the vehicle body is locked between the auxiliary wheel and the vehicle body. A vehicle body swing control device for an industrial vehicle, comprising: a second swing control mechanism for 2. The vehicle body swing control device for an industrial vehicle according to claim 1, wherein the timing at which the second swing control mechanism operates is later than the timing at which the first swing control mechanism operates. . 3. The vehicle body swing control device for an industrial vehicle according to claim 1, wherein the link mechanism is attached to the vehicle body via a suspension spring. 4. The vehicle body rocking control device for an industrial vehicle according to claim 3, wherein the first rocking regulation mechanism operates when the expansion / contraction amount of the suspension spring reaches or exceeds a set value. 5. The method according to any one of claims 1 to 4,
A vehicle body swing control device for an industrial vehicle, wherein the second swing restriction mechanism operates when the amount of expansion and contraction of the elastic member reaches or exceeds a set value. 6. The method according to any one of claims 1 to 5,
The vehicle body swing control device has a lateral acceleration measuring means, and when the measured value of the lateral acceleration applied to the vehicle reaches or exceeds each set value, the first swing restricting mechanism and the second swing restricting mechanism are activated. A vehicle body swing control device for an industrial vehicle, which is characterized in that each of them operates. 7. The method according to any one of claims 1 to 6,
The vehicle body swing control device has yaw rate measuring means, and when the measured value of the yaw rate applied to the vehicle reaches or exceeds the respective set values, the first swing control mechanism and the second swing control mechanism operate respectively. A vehicle body rocking control device for an industrial vehicle, comprising: 8. The method according to any one of claims 1 to 7,
The vehicle body swing control of an industrial vehicle, wherein the first swing control mechanism and the second swing control mechanism operate when the tilt angle of the link in the link mechanism reaches or exceeds respective set values. apparatus. 9. The method according to claim 1, wherein
The vehicle body swing control device includes turning change measuring means for measuring a yaw rate change rate or a lateral acceleration change rate of the vehicle,
A vehicle body swing control device for an industrial vehicle, wherein at least the first swing control mechanism operates when the yaw rate change rate or the lateral acceleration change rate reaches or exceeds a preset value. 10. The yaw rate change rate or the lateral acceleration change rate, which is the measured value of the turning change measuring means, is used to determine the lock control with respect to the operation timing of the second rocking regulation mechanism. A vehicle body swing control device for an industrial vehicle, which is set so as not to be considered as a parameter. 11. A vehicle body of an industrial vehicle according to claim 6, wherein the lateral acceleration measuring means selectively measures only the lateral acceleration when the vehicle is turning. Swing control device. 12. The lateral acceleration measuring means according to claim 6, wherein the lateral acceleration measuring means includes a steering angle detector that detects a steering angle of steered wheels, a vehicle speed detector that detects a vehicle speed of the vehicle, and A vehicle body swing control device for an industrial vehicle, comprising: a lateral acceleration estimating means for estimating the lateral acceleration by a calculation using both detection data of a steering angle and a vehicle speed. 13. The yaw rate detector for detecting the yaw rate of the vehicle, the vehicle speed detector for detecting the vehicle speed of the vehicle, and the yaw rate and the vehicle speed according to any one of claims 6 to 12. And a lateral acceleration estimating means for estimating a lateral acceleration by a calculation using both of the detection data described above. 14. The lateral acceleration measuring means according to claim 6, wherein the lateral acceleration measuring means is an acceleration sensor, and determines whether or not the lateral acceleration detected by the acceleration sensor is during turning of the vehicle. A vehicle body swing control device for an industrial vehicle, comprising: 15. The turning change measuring means according to claim 9, wherein the turning change measuring means includes a vehicle speed detector for detecting a vehicle speed of a vehicle and a detector provided for measuring the lateral acceleration. Turning change rate estimating means for estimating the yaw rate change rate or the lateral acceleration change rate by calculation using detectors other than the vehicle speed detector and two detection data including vehicle speed detection data detected by both detectors. A vehicle body swing control device for an industrial vehicle, comprising: 16. The vehicle body rocking control device according to claim 1, wherein a lock condition for operating the first rocking restricting mechanism and the second rocking restricting mechanism is not satisfied. The vehicle body swing control device for an industrial vehicle, which is set so as to stop the operation of the first swing control mechanism and the second swing control mechanism after a predetermined time has elapsed from the point of time. 17. The first swing restricting mechanism and the second swing restricting mechanism according to claim 1, wherein the first swing restricting mechanism and the second swing restricting mechanism are set based on a set value when the first swing restricting mechanism and the second swing restricting mechanism operate.
A vehicle body swing control device for an industrial vehicle, wherein a set value when the operation of the swing control mechanism is stopped is set small. 18. The regulating mechanism according to claim 1, wherein the first swing regulation mechanism includes regulation force adjusting means capable of regulating a regulation force applied to the link mechanism for locking. The lock control is performed by controlling the regulating force adjusting means, and when the operation of the first swing regulating mechanism is stopped, the regulating force adjusting means is set so that the lock of the link mechanism is gradually released. A vehicle body swing control device for an industrial vehicle, which is controlled. 19. The yaw rate change rate or the lateral acceleration change rate according to any one of claims 1 to 18, wherein the turning change measuring means is operated by using detection data of a plurality of detectors including a vehicle speed detector. The vehicle body swing control device for an industrial vehicle according to claim 1, wherein the calculation formula used to calculate the measured value includes a time differential term of the vehicle speed. .