JP3161365B2 - Body swing control device for industrial vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial vehicle body swing control device for fixing an axle swingably provided on the body of an industrial vehicle when predetermined traveling conditions and the like are satisfied. .

[0002]

2. Description of the Related Art Conventionally, in an industrial vehicle such as a forklift, an axle supporting a rear wheel is swingably attached to a vehicle body in order to stabilize the vehicle during traveling. When the forklift turns, the vehicle body tilts in the lateral direction due to the lateral force due to the centrifugal force. For this reason, running stability decreases during turning.

Japanese Patent Application Laid-Open No. 58-211903 discloses a forklift provided with a turning detecting means for detecting a centrifugal force. When the centrifugal force acting on the vehicle exceeds a predetermined value, the axle is fixed by an axle fixing mechanism. Techniques are disclosed. In this forklift, the axle is fixed at the time of turning and the tilting of the vehicle body is suppressed, so that the forklift can turn in a stable state.

[0004]

However, when the lateral acceleration (lateral G) caused by the centrifugal force is viewed only, there is a problem that the timing for fixing the axle is delayed. In other words, the axle is not immediately fixed even if the direction of the vehicle body begins to change due to turning of the steering wheel for turning, and the axle is fixed only when the lateral G reaches or exceeds the set value. Therefore, there is a possibility that the axle may be fixed in a state where it is slightly inclined from the horizontal.

[0005] Further, when turning back from left (right) turning to right (left) turning, there is a place where the lateral G becomes almost "0" for a moment in the middle, and in this vicinity, the lateral G becomes less than the set value and the axle is turned. Will be released. Therefore, at the time of this switching operation, there is a possibility that the axle swings and the vehicle body becomes unstable.

[0006] As one of the measures, the applicant of the present application detects a change in the direction of the vehicle body in addition to the lateral G, and observes the change in the direction of the vehicle body. Proposal of fixing technology (Japanese Patent Application No. 8-14)
No. 9560). That is, by attaching a detector such as a gyroscope to the vehicle body, detecting the yaw rate (angular velocity) ω, and subtracting the yaw rate ω with respect to time,
Yaw rate change rate ΔY which is a temporal change in the direction of the vehicle body
= Δω / ΔT is calculated. And the yaw rate change rate Δ
This is a technique for fixing the axle even when Y / ΔT becomes equal to or greater than the set value yo.

[0007] According to this technique, the axle is fixed earlier when the direction of the vehicle body begins to change after turning the steering wheel for turning, thereby avoiding delay in fixing the axle. Also, during the reversing operation, the axle fixing is continued even in the section where the lateral G is less than the set value on the way, because the yaw rate change rate ΔY / ΔT is equal to or more than the set value yo. And the stability of the vehicle body is maintained.

By the way, the centrifugal force acting on the vehicle body when turning is
The smaller the turning radius and the higher the vehicle speed, the larger the turning radius. Since the yaw rate is a physical quantity that is not affected by the vehicle speed, the yaw rate change rate ΔY / ΔT is also a physical quantity that is not affected by the vehicle speed. Therefore, in order to determine the timing of fixing the axle, it is necessary to consider not only the time change of the yaw rate of the vehicle but also the vehicle speed at that time.

[0009] Even when the yaw rate of the vehicle changes in a similar manner when the steering wheel is turned, the rising change of the lateral G becomes larger during high-speed running than at low-speed running. Therefore, in order to cope with any vehicle speed, the set value yo of the yaw rate change rate ΔY / ΔT is considered in consideration of high-speed running.
Had to be set lower. However, the set value y
If o was set low, the axle would be fixed more than necessary at low speeds. It is actually desirable that the axle not be locked more than necessary. This is because if the axle is locked while traveling on uneven road surface with the vehicle weight on the rear wheel side, there is a risk that one of the front wheels, which is the drive wheel, may be lifted, which is the cause This is because a slip is caused.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. A first object of the present invention is to restrain the axle from oscillating quickly at the start of a turn with a small delay in timing, and to swing the axle when switching. It is an object of the present invention to provide a vehicle body swing control device for an industrial vehicle that can maintain the state in which the movement is restricted and can reduce unnecessary axle swing restriction as much as possible. Also,
A second object is to suppress unnecessary axle swing even in a low-speed range where the vehicle speed is low, and to reliably limit axle swing when necessary. A third object is to obtain necessary measurement values without providing an acceleration detector. 4th
It is an object of the present invention to suppress the roll of the vehicle body due to hitting a projection or the like on a road surface when the vehicle changes direction. A fifth object is to improve the reliability of a measurement value indirectly calculated from a detection value of each detector provided in the vehicle.
A sixth object is to appropriately regulate axle swing even when the vehicle speed changes.

[0011]

In the invention described in 請 Motomeko 1 Means for Solving the Problems], an axle swingably supported relative to the vehicle body of the vehicle,
An axle regulating mechanism for regulating swing of the axle, a lateral G measuring means for measuring a lateral G of the vehicle, a lateral G change measuring means for measuring a rate of change of the lateral G with respect to time, wherein the lateral any of the measured values of the G rate of change becomes the respective set value or more, and a control means for actuating the axle restricting mechanism so as to restrict the swinging of the axle, the time of the yaw rate of the vehicle
A yaw rate change measuring means for measuring a change rate with respect to,
Vehicle speed detecting means for detecting a vehicle speed, wherein the control means
Determining means for determining whether or not the vehicle speed is less than a set value;
In addition, it is provided in the low speed range where the vehicle speed is less than the set value.
Sometimes, instead of the lateral G change rate,
Of the lateral G and the yaw rate change
If any of the conversion ratios exceeds each set value, the axle
It is necessary to operate the axle control mechanism to control the swing of
And the summary.

[0012] In the invention described in 請 Motomeko 2, the body swing control apparatus for industrial vehicle according to claim 1, said vehicle
Is provided with two or more detectors that are different from each other,
Calculation using two or more detection values detected by the detector
By this, it was determined whether or not the axle swing should be restricted.
Measurement value calculating means for calculating each of the measurement values for
Setting means.

[0013] 請 in the invention described in Motomeko 3, the body swing control apparatus for industrial vehicle according to 請 Motomeko 2, the measurement value
The calculating means calculates the lateral G change rate or
-When calculating the rate change rate,
The detection values of the two detectors that are hard to pick up the vibration are subtracted.

[0014] The invention according to claim 4, in body swing control apparatus for industrial vehicle according to claim 2, two or more
A vehicle speed detector is provided as one of the detectors,
The calculating means calculates two or more lateral G change rates as the measured values.
The horizontal G having the detection value of the above detector as a variable is calculated.
Time derivative of the theoretical equation
The calculation is performed using a calculation formula that is not ignored.

[0015] In the invention described in 請 Motomeko 5, the body of the vehicle
An axle supported to be swingable with respect to the
Axle regulation mechanism for regulation and measurement of lateral G of vehicle
Horizontal G measuring means, and measures the rate of change of the horizontal G with respect to time
Lateral G change measuring means, and the lateral G and the lateral G change rate
When any one of the measured values is equal to or more than each set value,
Activate the axle regulation mechanism to regulate axle swing
Control means, wherein the vehicle has two different detection targets.
The above-described detectors are provided, and each detector is detected.
The axle swings by calculation using two or more detected values.
Calculate each of the above measured values to determine whether or not to regulate
While each of the measurement means includes a measurement value calculation means to perform,
The measured value calculating means calculates a lateral G change rate among the measured values.
When calculating the vehicle vibration of each of the detectors
Difference between the detection values of the difficult detectors.

[0016] In the invention described in 請 Motomeko 6, in the body of the vehicle
An axle supported to be swingable with respect to the
Axle regulation mechanism for regulation and measurement of lateral G of vehicle
Horizontal G measuring means, and measures the rate of change of the horizontal G with respect to time
Lateral G change measuring means, and the lateral G and the lateral G change rate
When any one of the measured values is equal to or more than each set value,
Activate the axle regulation mechanism to regulate axle swing
Control means, wherein the vehicle has two different detection targets.
The above-described detectors are provided, and each detector is detected.
The axle swings by calculation using two or more detected values.
Calculate each of the above measured values to determine whether or not to regulate
While each of the measurement means includes a measurement value calculation means to perform,
A vehicle speed detector is provided as one of the two or more detectors,
The measured value calculating means calculates a lateral G change rate as the measured value.
And the horizontal G having the detection values of the two or more detectors as variables
Time derivative of the theoretical formula for calculation
Use a calculation formula that does not ignore the interderivative term.
Was.

[0017] In the invention described in 請 Motomeko 7, the body swing control apparatus for industrial vehicles according to any one of claims 2 to 6, wherein the vehicle is steered as the detector
Steering angle detector to detect wheel steering angle and vehicle speed
A vehicle speed detector, wherein the measurement value calculating means includes: a steering angle;
The measured values are calculated using both detected values of the vehicle speed. Claim
In the invention described in claim 8, any one of claims 2 to 6 can be used.
The vehicle body swing control device for an industrial vehicle according to claim 1
The vehicle has a yaw rate of a vehicle body as the detector.
Yaw rate detector to detect and vehicle speed detection to detect vehicle speed
A measuring device, wherein the measurement value calculating means includes a yaw rate and a vehicle speed.
Each of the measured values is calculated using both the detected values.

(Operation) Therefore, according to the first , fifth , and sixth aspects of the invention, the lateral G of the vehicle is measured by the lateral G measuring means, and the change rate of the lateral G with respect to time is measured by the lateral G change measuring means. Measured. Horizontal G
If any of the measured values of the lateral G change rate and the set values are equal to or greater than the respective set values, the axle restricting mechanism is operated by the control means to restrict the axle swing. When the vehicle turns, the lateral G change rate becomes equal to or higher than the set value, so that the swing of the axle is quickly regulated without delay at the start of the turn. Also,
When switching from left (right) turning to right (left) turning,
Since the rate of change is equal to or greater than the set value, the swinging of the axle is maintained in a state of being restricted at the time of this switching.

Further, the lateral G change rate is a value in which the factor of the vehicle speed is considered, and the set value is set to be lower in accordance with the high speed as in the case of using the change rate of the yaw rate in which the factor of the vehicle speed is not considered. There is no need to keep. Therefore, it is possible to set an appropriate set value common to the high speed and the low speed of the vehicle speed, and it is possible to minimize unnecessary axle swing regulation.

In particular, in the first aspect of the present invention, the rate of change of the yaw rate of the vehicle with respect to time is measured by the yaw rate change measuring means. The vehicle speed is detected by the vehicle speed detecting means. The determination means determines whether the vehicle speed is less than the set value. When the vehicle speed is in a high-speed region where the vehicle speed is equal to or higher than a set value, the control by the control means to regulate the axle swing due to factors other than the lateral G is performed based on the lateral G change rate. In some cases, this is performed based on the yaw rate change rate. At low speeds, the measured value to see the change over time at low speeds (measured value other than lateral G) by using the yaw rate change rate less affected by the vehicle speed than the lateral G change rate or not affected by the vehicle speed Can be set higher.

According to the second aspect of the present invention, each measured value for determining whether or not the swing of the axle should be restricted is determined by two or more detectors provided on the vehicle and having different detection targets. It is calculated by the measured value calculating means using two or more detected values. Therefore, necessary measurement values can be obtained without providing an acceleration detector for directly detecting the lateral G.

According to the third aspect of the present invention, the measurement value calculation
The output means calculates the lateral G change rate or the yaw rate change rate
In the detection, it is difficult to detect the vehicle vibration among the detectors.
The detected value of the transmitter is subtracted. For this reason, originally low noise
Detection value is subtracted, the difference (differential)
There is no fear of amplification. Claim 4 and claim 6
According to the invention, the measurement value calculation means includes one vehicle speed detector.
From the detected values of two or more detectors
The G change rate is calculated. This formula is based on the detection value of each detector.
Time derivative of the theoretical formula for calculating the lateral G with
And the time derivative of the vehicle speed is not neglected.
The more accurate calculation of lateral G change rate corresponding to changes in vehicle speed
The bid price is obtained.

According to the fifth aspect of the invention, the measurement value calculation
In calculating the lateral G change rate, the output means sets each detector
Among them, the detection value of the detector which is hard to pick up the vibration of the vehicle is subtracted.
For this reason, detection values originally having low noise are subtracted.
Therefore, there is no fear that noise is amplified by the difference (differential).

According to the seventh aspect of the present invention, the steering angle detection is performed.
The steering angle of the steered wheel detected by the driver and the vehicle speed detector
By using each detected value with the detected vehicle speed,
Whether the axle swing should be regulated by the measurement value calculation means
Each measurement value required for the determination of is calculated.

According to the invention described in claim 8, yaw rate
The vehicle yaw rate detected by the
Using each detected value with the vehicle speed detected by the
The axle swing should be restricted by the measurement value calculation means
The respective measurement values required for determining whether or not are determined. Also a car
Since both yaw rates are used, even if the steered wheels
The G change rate is accurately calculated. In addition, the vehicle speed
The configuration that adopts the yaw rate change rate in the full low speed range
In the case, the side G is
Even if the value is less than the set value, the value detected by the yaw rate
The required rate of change in yaw rate is not affected by vehicle speed
From which the rate of change of the yaw rate is
Swing of the axle is well regulated during turning. Follow
Even if the wheel stumbles on a bump on the road surface when turning
Because the axle does not swing, the vehicle body can roll greatly
Be avoided.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

The forklift 1 as an industrial vehicle in this embodiment is a four-wheeled vehicle driven by front wheels and steered by rear wheels.
An inner mast 3 is provided between a pair of left and right outer masts 2 erected at the front of the machine stand of the forklift 1 so that the inner mast 3 can be moved up and down via a chain (not shown). It is suspended in. The outer mast 2 is connected to a vehicle body frame 1a as a vehicle body via a tilt cylinder 5, and is tilted when a piston rod 5a of the tilt cylinder 5 is driven to expand and contract. The piston rod 6a of the lift cylinder 6 disposed on the back surface of the outer mast 2 is connected to the upper end of the inner mast 3, and the fork 4 is moved up and down by the expansion and contraction drive of the piston rod 6a of the lift cylinder 6. Has become.

The left and right front wheels 7 are operatively connected to an engine 9 via a differential ring gear 8 (shown in FIG. 1) and a transmission (not shown), and are driven by the power of the engine 9. As shown in FIGS. 1 and 2, a rear axle 10 as an axle is supported at the rear lower portion of the body frame 1a so as to be swingable (rotatable) about a center pin 10a in a state of extending in the vehicle width direction. I have. The left and right rear wheels 11 are steerably connected via link mechanisms (not shown) at respective distal ends of a pair of left and right piston rods of a steering cylinder (not shown) disposed on the rear axle 10. The steering wheel is supported so as to be able to swing integrally with the rear axle 10. The left and right rear wheels 11 are steered by driving the steering cylinder based on the operation of the steering wheel 12.

One hydraulic damper (hereinafter simply referred to as "damper") 13 is provided between the body frame 1a and the rear axle 10 so as to connect the two.
The damper 13 is a double-acting hydraulic cylinder, and a cylindrical cylinder 13a of the damper 13 is provided on the body frame 1a side.
The front end of a piston rod 13c extending from a piston 13b housed in a cylinder 13a is connected to the rear axle 10 side.

The damper 13 serves as a switching valve via a first pipe P1 and a second pipe P2 which are connected to each of a first chamber R1 and a second chamber R2 partitioned by a piston 13b. Are connected to the electromagnetic switching valve 14. Solenoid switching valve 14
Is a normally closed 2-port 2-position switching valve that closes when demagnetized, and has a spool formed with a stop valve portion 15 and a flow valve portion 16. The third pipe P2
An accumulator 17 for storing hydraulic oil via a pipeline P3
Are connected via a check valve 18.

By disposing the spool of the electromagnetic switching valve 14 at the shut-off position shown in FIG. The swing of the axle 10 is locked. On the other hand, the damper 13 is operated between the two chambers R1 and R2 by disposing the spool of the electromagnetic switching valve 14 at the communicating position with the body (the state where the spool position is switched to the opposite side from the state of FIG. 2). The oil is in a free state in which the outflow / inflow of the oil is possible, and the swinging of the rear axle 10 is allowed. Further, a throttle valve 19 is provided on the path of the second pipeline P2. Note that an axle control mechanism is constituted by the damper 13, the electromagnetic switching valve 14, and the like.

As shown in FIGS. 1 and 2, on one side of the king pin 20 that rotatably supports the rear wheel 11, the rotation amount of the king pin 20 is detected to detect the steering angle (tire angle) of the rear wheel 11.
θ to constitute a lateral G measuring means and a lateral G change measuring means, and a tire angle sensor 21 as a steering angle detector.
Is provided. The tire angle sensor 21 includes, for example, a potentiometer. As shown in FIG. 1, the differential ring 8 detects the rotation of the differential ring gear 8 to detect the vehicle speed V of the forklift 1 to constitute lateral G measuring means and lateral G change measuring means. A vehicle speed sensor 22 is provided as a container.

As shown in FIG. 1, the outer mast 2
Is provided at a predetermined height with a lift sensor 23 composed of, for example, a limit switch. The lift sensor 23 is turned on when the lift of the fork 4 exceeds the set value ho, and the set value ho
It is set to turn off with less than. In this embodiment, the set value ho is set to half the maximum lift height hmax. Further, the lift cylinder 6 is provided with a pressure sensor 24 for detecting the oil pressure inside the cylinder. The pressure sensor 24 outputs a detection value according to the load w on the fork 4.

Next, the electrical configuration of the forklift 1 will be described with reference to FIG. The forklift 1 is provided with a controller 25 as control means for performing swing control and the like to be described later. The controller 25 includes a microcomputer 26, AD conversion circuits 27 to 29, an excitation / demagnetization drive circuit 30, and the like. Microcomputer 2
Reference numeral 6 denotes a CPU (central processing unit) 31, a ROM (read-only memory) 32, a RAM (read-write memory) 33, which constitute the horizontal G measuring means and the horizontal G change measuring means, and serve as measured value calculating means. A clock circuit 34, counters 35 and 36, an input interface 37, and an output interface 38 are provided.

The CPU 31 stores the detected values θ, from the tire angle sensor 21, the vehicle speed sensor 22, and the pressure sensor 24,
V and w are input via the AD conversion circuits 27 to 29, and an on / off signal from the elevation sensor 23 is input. Further, the electromagnetic switching valve 14 has a C
The excitation current from the excitation / demagnetization drive circuit 30 to the solenoid 14a is turned on based on the control signal output from the PU 31.
The switching is controlled by being turned off and the solenoid 14a being demagnetized. That is, CPU
When the lock signal is output from 31 and the excitation current to the solenoid 14a is cut off from the excitation / demagnetization drive circuit 30 and the solenoid 14a is demagnetized, the electromagnetic switching valve 14 is placed in the cutoff position. Then, an unlock signal is output from the CPU 1 and the solenoid 14
When the exciting current flows through the solenoid a and the solenoid 14a is excited, the electromagnetic switching valve 14 is arranged at the communicating position.

Various kinds of program data are stored in the ROM 32, and one of them is the program data of the swing control processing shown in the flowcharts of FIGS. Here, the swing control means the rear axle 10
In the present embodiment, the lateral G acting on the vehicle (centrifugal acceleration acting in the lateral direction of the machine when turning) Gs and the temporal change rate Δ of the lateral G are locked.
G / ΔT is a measured value, and when one of the Gs value and ΔG / ΔT value exceeds each set value, the rear axle 10
Is set to lock the swing of In the flowcharts of FIGS. 7 and 8, S10 to S30 constitute the horizontal G measuring means, and S10, S20, and S40 are the horizontal G measuring means.
It constitutes a change measuring means.

The set value of the horizontal G (Gs) is shown in FIG.
As shown in the map of (b), it is set according to the load w and the lift H. That is, when the load w is less than the set value w0, as shown in FIG. 6A, when the lift H is less than ho (the lift sensor 23 is turned off), the set value is "G".
When the lift H is equal to or greater than ho (the lift sensor 23 is turned on), the set value is set to “G1” (G1 = G2 / 2 in the present embodiment). When the load w is equal to or more than the set value w0, as shown in FIG. 6B, the set value is set to "G2" when the lift H is less than ho, and is always set when the lift H is equal to or more than ho. Rear axle 1
0 is set to be locked.

The ROM 32 stores a lateral G change rate ΔG /
The set value go of ΔT is stored. Each set value G1, G
2, go is a value obtained from a driving experiment or a theoretical calculation, and is set so that the rear axle 10 is locked at a necessary time for driving stability. The CPU 31 has two flags Fg and Fgv. The flag Fg is set when the horizontal G (Gs) exceeds the set value G1 or G2, and when the horizontal G change rate ΔG / ΔT becomes equal to or more than the set value go. The flag Fgv is set.

The ROM 32 stores a map for obtaining the reciprocal value 1 / r of the turning radius of the vehicle from the tire angle θ. In the present embodiment, the lateral G (Gs) is estimated by calculation using two detected values θ and V from the tire angle sensor 21 and the vehicle speed sensor 22. Estimated value Gs of lateral G
Is given by the following equation (1) using the reciprocal value 1 / r of the turning radius determined from the tire angle θ.

Gs = V ² / r (1) The time difference ΔG / ΔT of the horizontal G is expressed by the following equation (2). ΔG / ΔT = V ² Δ (1 / r) / ΔT (2) In the present embodiment, the lateral G change rate ΔG / ΔT is expressed by (2)
It is calculated by the following equation using the two detected values θ and V based on the relationship of the equation.

ΔG / ΔT = V ² | 1 / r−1 / r1 | where ΔG / ΔT is the change amount of the lateral G per predetermined time ΔT (for example, several tens of milliseconds), 1 / r, 1 / r1 is a reciprocal value of the turning radius before and after the predetermined time ΔT has elapsed, respectively. In the present embodiment, the tire angle data θ for a plurality of past times (the control time interval ΔTo is one time) is stored in the RAM 32.
And a predetermined time ΔT (= n · ΔT
o) The previous tire angle data θ1 is read, and the reciprocal value 1 of each turning radius determined from the current detection value θ and the old detection value θ1 respectively.
Δ (1 / r) / ΔT is approximated by the difference between / r and 1 / r1 (= | 1 / r-1 / r1 |). In the present embodiment, for example, the tire angle θ takes a negative value at the left turning angle, and a positive value at the right turning angle, and the reciprocal value 1 / r obtained from the θ value also corresponds thereto. With a sign.

By the way, ΔG / ΔT corresponds to the time derivative of the equation (1) and is expressed by the following equation. ΔG / ΔT = V ² Δ (1 / r) / ΔT + (1 / r) 2 VΔV / ΔT (3) In the equation (3), the latter term ΔV / ΔT is the time-dependent change of the vehicle speed V. Normally, in the forklift 1, the vehicle speed V during the turning can be regarded as substantially constant.
The ΔT value is a value sufficiently smaller than the Δ (1 / r) / ΔT value in the preceding section. Therefore, in the present embodiment, the above equation (2) approximated by ignoring the latter term in the equation (3) is employed for estimating ΔG / ΔT.

In this embodiment, the load w, the lift H,
A measure is taken to prevent frequent switching between lock and unlock due to the lateral G change rate ΔG / ΔT taking a value near the set value. That is, when the flag Fgv is “1”, “go” is set as the set value for ΔG / ΔT.
A smaller set value “α · go” is adopted, and when the flag Fg is “1”, “wo” and “h” are set values for Gs.
The set values “α · wo” and “α · ho” (for example, 0.5 <α <1) smaller than “o” are adopted.

The two counters 35 and 36 are for measuring a predetermined time T based on the clock signal from the clock circuit 34, and have a horizontal G (Gs) and ΔG / ΔT
Are the values to be unlocked (that is, the judgment values Gs, ΔG
/ ΔT is less than each set value go, G1, G2, G3). The lock is released after the lock release condition is satisfied for a predetermined time T, and the two counters 35, 3
Numeral 6 is for measuring the duration time.

Next, the swing control of the forklift 1 will be described with reference to the flowcharts of FIGS. While the ignition key is on, each sensor 21 to 24
Detection signals θ, V, w, etc. from the
The CPU 31 executes the swing control process at intervals of a predetermined time ΔTo (for example, 10 to 50 milliseconds).

First, in step 10, the CPU 31 reads the detected values of the tire angle θ, the vehicle speed V, and the load w. In step 20, the reciprocal value 1 / r of the turning radius is obtained from the tire θ using the map stored in the ROM 32.

In step 30, the vehicle speed value V and the turning radius are calculated.
From the equation (1) using the reciprocal value 1 / r, the estimated value G
s = V^Two/ R is calculated. In step 40, the lateral G change
The ratio ΔG / ΔT is calculated. That is, the predetermined
Reads tire angle data θ1 before a predetermined time ΔT from the storage area.
And a turning radius before a predetermined time ΔT obtained from the θ1 value.
, The current 1 / r value, and the vehicle speed value V
Used, ΔG / ΔT = V ^Two・ | 1 / r-1 / r1 |
Using the equation, the lateral G change rate ΔG / Δ based on the relationship of equation (2)
Calculate T.

In step 50, ΔG / ΔT is equal to the set value g.
o Determine if this is the case. ΔG / ΔT is set value g
If it is equal to or more than 0, the process proceeds to step 60, where "1" is set in the flag Fgv. If ΔG / ΔT is less than the set value go, the routine proceeds to step 70, where the unlock condition (ΔG / ΔT <go when Fgv = 0, ΔG / ΔT when Fgv = 1)
It is determined whether or not <α · go) holds for a predetermined time T. The counter 35 measures the time T.
Each time / ΔT ≧ go holds, the counter 35 is reset, and ΔG / ΔT <go or ΔG / ΔT <α · g
o The counting of the counter 35 is started each time the condition is satisfied.

In step 70, when the counter 35 has not counted the predetermined time T, the routine proceeds to step 90, where the flag Fgv is not changed. On the other hand, if the lock release condition is satisfied for the predetermined time T, the routine proceeds to step 80, where the flag Fgv is set to "0". In other words, the lock is not released immediately when the lock release condition is satisfied, but the lock release is delayed by a predetermined time T.

The next steps 90 to 170 are for determining whether the rear axle 10 should be in a free state or a locked state based on the lateral G (Gs). In the present embodiment, the free / lock determination of the rear axle 10 based on the lateral G (Gs) is performed as shown in FIG.
As shown in the maps (a) and (b), the determination is performed based on the set values G1, G2, and the like set according to the load w and the lift H.

In step 90, it is determined whether or not the load w is equal to or greater than the set value w0. If the load w is less than the set value wo, the process proceeds to step 100, and if the load w is equal to or more than the set value wo, the process proceeds to step 110.

When the load w is less than the set value wo,
In step 100, it is determined whether or not the height H is equal to or greater than a set value ho. When the lift H is less than the set value ho, it is determined in step 120 whether or not Gs ≧ G2 is satisfied. When the lift H is not less than the set value ho, it is determined in step 130 whether Gs ≧ G1 is satisfied. Determine whether or not. In each step, when Gs ≧ G2 or Gs ≧ G1, the process proceeds to step 150, and the flag Fg is set to “1”. In each step, if Gs ≧ G2 or Gs ≧ G1 is not satisfied (that is, if Gs <G2 or Gs <G1), the routine proceeds to step 160. At step 160, the lock release condition (that is, Gs <G2 or Gs <G1)
It is determined whether or not the condition is continuously established. The counter 36 counts the predetermined time T. The counter 36 is reset each time Gs ≧ G2 or Gs ≧ G1 holds, and Gs ≧ G2.
Each time <G2 or Gs <G1 holds, the counter 36 starts counting time.

In step 160, when the counter 36 has not counted the predetermined time T (when the unlocking condition has not continued for the predetermined time T), the process proceeds to step 180, and the flag Fg is not changed. On the other hand, if the lock release condition is satisfied for the predetermined time T, the routine proceeds to step 170, where the flag Fg is set to "0". That is, also in this case, the lock is not immediately released at the same time as the lock release condition is satisfied, but the lock release is delayed by a predetermined time T.

On the other hand, when the load w is equal to or larger than the set value w0, it is determined in step 110 whether the lift H is equal to or larger than the set value ho. Then, the lift H is equal to the set value h.
o In the above case, the routine proceeds to step 150, where "1" is set in the flag Fg. When the height H is less than the set value ho, the routine proceeds to step 140, where it is determined whether or not Gs ≧ G2 holds. When Gs ≧ G2 holds, at step 150, the flag Fg is set to “1”. Further, Gs ≧ G2 is not satisfied (that is, Gs <G
In the case of 2), the routine proceeds to step 160, where it is determined whether or not the lock release condition (that is, Gs <G2) is continuously satisfied for a predetermined time T. If the condition is satisfied, the flag Fg is set to "1" in step 170. "0" is set, and if not satisfied, the flag Fg is not changed and the next step 18
Go to 0.

In step 180, if either of the flags Fgv and Fg is "1", a lock command (lock signal) is output. As a result, when at least one of the lateral G (Gs) and the lateral G change rate ΔG / ΔT exceeds each set value, the electromagnetic switching valve 14 is switched to the shut-off position and the rear axle 10 is locked.

FIG. 5 is a graph showing changes in the lateral G (Gs) and the lateral G change rate ΔG / ΔT during turning. In this graph, for example, when the vehicle turns left from straight ahead during traveling, the lateral G change rate ΔG / Δ, which is the rising change of lateral G,
When T (for example, (ΔG / ΔT) H) exceeds the set value go, the rear axle 10 is locked. for that reason,
The rear axle 10 is locked almost immediately at the same time as the turning start, and the lock timing is not delayed. Then, since the lateral G (Gs) immediately exceeds the set value, the tire angle θ
, The lock of the rear axle 10 is held as it is even when the lateral G change rate ΔG / ΔT becomes small due to the constant angle of inclination.

Then, the steering wheel 12 is turned from the left turn to the right turn.
When changing from the right side G to the left side G, there is a section where the side G is extremely short but less than the set value. However, the horizontal G is the set value (G1,
G2), the lateral G change rate ΔG / ΔT exceeds the set value go because the tire angle θ is changing. Therefore, the lock of the rear axle 10 is not released during the turning. In addition, since there is a time delay when the lock is released, an overlap in which both become “1” when the flag Fgv = 1 and the flag Fg = 1 are switched is secured. The lock is not unlocked due to a slight shift in the timing of the change in the horizontal G value.

Here, in the present embodiment, whether or not to lock is determined by looking at the lateral G change rate ΔG / ΔT instead of looking at the yaw rate change rate ΔY / ΔT. The lateral G change rate ΔG / ΔT has V ² as a factor as is apparent from the above equation (2). On the other hand, the yaw rate change rate Δ
Although Y / ΔT will be described later, the equation ΔY / ΔT = V · Δ (1 /
r) / ΔT. That is, the yaw rate change rate ΔY
/ ΔT has V as a factor. Therefore, as shown in the graph of FIG. 5, the lateral G change rate ΔG / ΔT is significantly different between high-speed running and low-speed running ((ΔG / ΔT) H and (ΔG / ΔT).
T) L). On the other hand, the yaw rate change rate ΔY / ΔT does not change with the vehicle speed as much as the lateral G change rate ΔG / ΔT ((ΔY / ΔT) H and (ΔY / ΔT) L). for that reason,
When the yaw rate change rate .DELTA.Y / .DELTA.T is adopted, the set value yo must be set relatively low in accordance with the high speed.

However, in the present embodiment, since the lateral G change rate ΔG / ΔT taking into account the influence of the vehicle speed is adopted, it is possible to set an appropriate set value go corresponding to the change in the vehicle speed. For example, as shown in FIG.
Even if the change rate (ΔG / ΔT) H is equal to or greater than the set value go and the rear axle 10 is locked,
At low speed traveling, the lateral G change rate (ΔG / ΔT) L is equal to the set value g.
The rear axle 10 is not locked because it is less than o.

Therefore, useless locking during low-speed running is reduced as compared with the case where the yaw rate change rate ΔY / ΔT is used for the determination of the lock control. Therefore, when the center of gravity of the vehicle is on the rear wheel 11 side, the swing of the rear axle 10 is locked, so that the ground pressure of one of the front wheels 7, which is the drive wheel, decreases, or the one wheel rises from the road surface. ,
The slip caused by this is reduced as much as possible. Note that GSH and GSL in FIG. 5 represent the lateral G during high-speed running and low-speed running, respectively.

In this embodiment, the rear axle 10
Once the lock is executed, the lock is not released unless the set value is slightly smaller than the set value at that time by α (for example, 0 <α <1). Therefore, each determination value ΔG / ΔT, H, w is set to its set value go, ho, w.
o Prevents frequent switching between lock and unlock due to accidental values around.

As described in detail above, according to the present embodiment,
The following effects can be obtained. (A) Lateral G change rate ΔG / Δ, which is a rise change of lateral G
T is adopted as one of the determination values for determining whether or not the rear axle 10 should be locked, so that the rear axle 10 can be locked quickly at the start of a turn, and the rear axle 10 is held in a locked state at the time of turning to stabilize the vehicle body. Nature can be secured.

(B) Transverse G change rate ΔG / V having V ² as a factor
Since ΔT is employed, it is possible to reduce useless lock at the time of low-speed running, which is a problem when the yaw rate change rate ΔY / ΔT is employed. For example, when the vehicle is traveling on an uneven road surface with the vehicle center of gravity being on the rear wheel 11 side, the rear axle 1
The occurrence of the problem that the front wheel 7 slips because the 0 is locked can be reduced as much as possible.

(C) The determination values ΔG / ΔT, Gs used for determining whether or not to lock are calculated by calculation using the detected values of the tire angle θ and the vehicle speed V. In addition, there is no need to provide a detector such as an acceleration sensor capable of directly detecting the lateral G. In particular, since the tire angle sensor 21 and the vehicle speed sensor 22 provided for other controls in the forklift 1 can be used for swing control, the cost of the apparatus can be relatively reduced by sharing the sensors.

(D) Set values (G1, G2) for determining whether or not to lock based on the lateral G (Gs) are set in accordance with the load w and the lift H in consideration of the change in the center of gravity of the vehicle. Therefore, useless locking when the center of gravity of the vehicle is low can be relatively reduced.

(F) Set values of horizontal G (Gs) (G1, G
2) is not separately changed in accordance with the load w and the lift H, but is separately set in two regions bounded by predetermined set values w o and ho. It's easy.

(G) In a configuration in which the lateral G is directly detected by the acceleration sensor, it is often thought that the lateral G change rate ΔG / ΔT may be obtained by directly performing a difference (differential) process on the detected lateral G value. The detection value of the acceleration sensor is easily affected by vibration of the vehicle body and the like, and noise due to vibration and the like is mixed in the detection value. Therefore, when a difference (differential) process is performed on the lateral G value, the noise is amplified, and the obtained estimated value Δ
G / ΔT is a value with poor reliability. On the other hand, according to the present embodiment, in calculating the ΔG / ΔT value, a method is used in which the 1 / r value obtained from the detection value θ of the tire angle sensor 21 that is hardly affected by vibration of the machine base or the like is subtracted. Therefore, the difference (differential) to the 1 / r value, which is very little affected by noise,
Even if the processing is performed, an error due to noise amplification hardly occurs, and a highly reliable estimated value ΔG / ΔT can be obtained.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to FIG. The present embodiment differs from the first embodiment in that the lateral G change rate ΔG / ΔT and the yaw rate change rate ΔY / ΔT are selectively used according to the vehicle speed. The ROM 32 stores the program data of the swing control process in which the part of FIG. 7 is replaced with the flowchart of FIG. 9 in the program data of the first embodiment, and other electrical configurations are described in the first embodiment. It has the same configuration as

In the first embodiment, a horizontal G having a factor of V ²
By adopting the change rate ΔG / ΔT, the set value go can be set higher, and unnecessary locking of the rear axle 10 is reduced. However, the lateral G change rate ΔG having V ² as a factor
/ ΔT draws a quadratic curve with respect to the variable V, whereas the yaw rate change rate ΔY / ΔT having V as a factor draws a linear line with respect to the variable V. Therefore, the vehicle speed V is in a low speed range (for example, a vehicle speed range where V <1 in the arithmetic processing of the CPU 31).
Then, in spite of the necessity of locking, the lateral G change rate ΔG / ΔT may become smaller than the set value go and the locking may not be achieved. Alternatively, if the set value go is set slightly lower in order to solve this, the rear axle 10 is unnecessarily locked in the high speed range. As a countermeasure against this, it is conceivable to set another set value for low speed with respect to ΔG / ΔT, but in this embodiment,
As one of the determination values in the low-speed range, V is a factor instead of ΔG / ΔT having V ² as a factor so that a set value that can reduce unnecessary lock more effectively in the low-speed range can be set. Is used as the measured value.

In the present embodiment, in consideration of the above, a predetermined value in the range of 5 to 10 km / h is set as the set value Vo for determining whether the vehicle speed V is high or low. I have. The maximum speed of the forklift 1 is 20 km /
h. Also, the yaw rate change rate ΔY / ΔT (=
Δω / ΔT (where ω is the yaw rate) is expressed by the formula ΔY / Δ
T = V · Δ (1 / r) / ΔT. In the present embodiment, using the reciprocal values 1 / r and 1 / r1 of the turning radius before and after the predetermined time ΔT has elapsed and the vehicle speed V, the yaw rate change rate ΔY / ΔT is calculated by the equation ΔY / ΔT = V · | 1 / r-1 / r
1 |.

The tire angle sensor 21 and the vehicle speed sensor 2
2 and the CPU 31 constitute a yaw rate change measuring means, and the CPU 31 constitutes a judging means. FIG.
In the flowchart of S10, S20, S210
Are the yaw rate change measuring means, S10, S20, S21
0, S220 is the lateral G change measuring means, S10, S20,
S230 constitutes the lateral G measuring means, and S240 constitutes the judging means.

The control by the CPU 31 is as follows. First, in step 10, the detected values θ, V, w, etc. from the sensors 21 to 24 are read, and in step 20, the tire angle θ
From the map, the reciprocal value 1 / r of the turning radius is calculated using a map.
In the next step 210, the yaw rate change rate ΔY / ΔT is calculated. That is, the tire angle data θ1 before the predetermined time ΔT is read from the predetermined storage area of the RAM 33, and the reciprocal value 1 / r1 of the turning radius obtained from the θ1 value using a map and the reciprocal value 1 / r based on the current detection value θ. And the vehicle speed value V, and ΔY / ΔT = V · | 1 / r−1 / r1 |
Calculate Y / ΔT.

In the next step 220, the lateral G change rate ΔG
/ ΔT = V · ΔY / ΔT is calculated. Then, in step 230 the lateral G is calculated by Gs = V ² / r. In step 240, it is determined whether or not the vehicle speed V is lower than the set value Vo. If the vehicle speed V is in the low speed range less than the set value Vo, in step 250, the yaw rate change rate ΔY / Δ
It is determined whether or not T is equal to or greater than the set value yo. If the vehicle speed V is in the high speed range equal to or greater than the set value Vo, it is determined in step 260 whether the lateral G change rate ΔG / ΔT is equal to or greater than the set value go. to decide.

In both steps 250 and 260, the respective lock conditions (ΔY / ΔT ≧ yo, ΔG /
When ΔT ≧ go) is satisfied, at step 270, the flag Fgv is set to “1”. On the other hand, when the unlock condition (ΔY / ΔT <yo, ΔG / ΔT <go) is satisfied, the routine proceeds to step 280, and if the time measured by the counter 35 is equal to or longer than the predetermined time T, the flag Fgv is set to “0” in step 290. If the time measured by the counter 35 is less than the predetermined time T, the process proceeds to the next step 90 without changing the flag Fgv. The processing after step 90 is the same processing as in FIG.

Therefore, when the vehicle is running at a high speed where the vehicle speed V is equal to or higher than the set value Vo, the rear axle 10 is locked when the lateral G change rate ΔG / ΔT becomes equal to or higher than the set value go. Also,
When the vehicle speed V is lower than the set value Vo, the rear axle 10 is locked when the yaw rate change rate ΔY / ΔT becomes equal to or more than the set value yo. That is, when ΔG / ΔT or ΔY / ΔT becomes equal to or more than the respective set values, the rear axle 10 is quickly locked at the start of turning. Further, since ΔG / ΔT or ΔY / ΔT is equal to or greater than the respective set values, the rear axle 10 is held in the locked state when switching.

In a high-speed region where the vehicle speed V is equal to or higher than the set value Vo, the set value go can be set higher by adopting the lateral G change rate ΔG / ΔT having V ² as a factor.
Useless locks can be reduced as much as possible. And the vehicle speed V
In a low-speed range where is smaller than the set value Vo, the yaw rate change rate ΔY / ΔT having V as a factor is adopted, so that the set value yo can be set higher even in the low-speed range. Useless locks can be reduced as much as possible.
Therefore, according to this embodiment, useless locking of the rear axle 10 in the low speed range can be further reduced as compared with the configuration of the first embodiment. Also, for example, the rear axle 1
It is possible to avoid the problem that the lock is not performed even when 0 is necessary.

In calculating ΔG / ΔT and ΔY / ΔT, a method of subtracting the 1 / r value determined from the detected value θ of the tire angle sensor 21 which is hardly affected by vibration of the machine base is adopted. As for the yaw rate change rate ΔY / ΔT, a highly reliable estimated value ΔY / ΔT can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the lateral G (Gs) and the lateral G change rate ΔG / ΔT
A detector for detecting a detection value used for estimating the above is different from the above embodiments.

As shown in FIG. 10, a horizontal G measuring means, a lateral G change measuring means and a yaw rate change measuring means are arranged on a balance weight 40 arranged at the rear of the forklift 1 and a gyro as a yaw rate detector is provided. A scope 41 is attached. In this embodiment, a piezoelectric gyroscope including a piezoelectric element is used as the gyroscope 41. For example, other types such as a gas rate gyroscope or an optical gyroscope can be used.

As shown in FIG. 11, the gyroscope 4
1 is an input interface 37 via an AD conversion circuit 42.
And detects a yaw rate (angular velocity) ω (rad / sec) at the time of turning of the forklift 1 and outputs a detected value ω corresponding to the yaw rate to the lateral G measuring means, the lateral G change measuring means, and the yaw rate change measuring means. And outputs it to the CPU 31 as a determining means and a measurement value calculating means. The present embodiment has a configuration in which a gyroscope 41 is provided as a detector in place of the tire angle sensor 21 used in each of the above embodiments, and the other configurations have the same configurations as those of the above embodiments. I have. However, ROM
32 is the same as that of the second embodiment shown in FIG.
2 is stored. Further, the lateral G is expressed by the equation Gs = V · ω, the yaw rate change rate ΔY / ΔT is expressed by the equation ΔY / ΔT = Δω / ΔT,
The lateral G change rate ΔG / ΔT is calculated by the equation ΔG / ΔT = V · Δω / ΔT
(= V · ΔY / ΔT).

The control by the CPU 31 is as follows.
First, in step 410, the CPU 31 reads each detected value such as the yaw rate ω, the vehicle speed V, and the load w. In step 420, the yaw rate change rate ΔY / ΔT is calculated. The CPU 31 stores yaw rate data for a plurality of past times before the predetermined time ΔT in a predetermined storage area of the RAM 33, reads the yaw rate data ω1 before the predetermined time ΔT, and uses the old detection value ω1 and the current detection value ω. , The yaw rate change rate ΔY / ΔT = Δω / ΔT (where Δω / ΔT =
| Ω-ω1 |). Next step 430
Then, the lateral G change rate ΔG / ΔT = V · ΔY / ΔT (= V ·
Δω / ΔT) is calculated. Then, in step 440, the horizontal G is calculated as Gs = V · ω.

The processing after step 240 is the same as that in the second embodiment. When the vehicle speed V is equal to or higher than the set value Vo, it is determined whether or not to lock based on the lateral G change rate ΔG / ΔT. When V is less than the set value Vo, it is determined whether or not to lock based on the yaw rate change rate ΔY / ΔT.

In the first and second embodiments, since the tire angle θ is used for calculating the lateral G change rate, the reliability of the calculated value of the lateral G change rate becomes poor when the rear wheel 11 slides. . However, according to this embodiment, since the yaw rate ω of the vehicle is used for calculating the lateral G change rate, the rear wheels 11
Can be accurately calculated even if the side slips.

For example, when the direction of the forklift 1 is changed, the vehicle speed is sufficiently reduced and the tire angle θ of the rear wheel 11 is greatly reduced. At this time, the vehicle body turns substantially around the front wheel 7. Become. In the configuration of the second embodiment, the yaw rate change rate ΔY / ΔT is determined by the vehicle speed V
(ΔY / ΔT = V · Δ (1 / r) / Δ
Therefore, at the time of a turn in which the vehicle speed is sufficiently reduced, ΔY / ΔT <yo, and a situation occurs in which the rear axle 10 is not locked.

However, in this embodiment, in the low speed range, the yaw rate change rate .DELTA.Y / .DELTA.
T (= Δω / ΔT) is used. Therefore, when the vehicle turns, even if the vehicle speed is low, the time change (Δω /
Since only ΔT) is observed, the ΔY / ΔT value becomes greater than or equal to the set value yo at the time of a direction change in which the direction of the vehicle greatly changes, and the rear axle 10 is securely locked. As a result, the direction is changed while the rear axle 10 is locked. For example, even if a tire hits a projection or the like on a road surface at the time of turning, the swinging of the rear axle 10 is restricted, so that the lateral inclination of the vehicle body at this time can be suppressed small.

In calculating ΔG / ΔT and ΔY / ΔT, the gyroscope 4 which is hardly affected by vibration of the machine base, etc.
1, a difference (differential) process is applied to the detection value ω having very little noise, and no significant error occurs due to amplification of the noise. The estimated values ΔG / ΔT and ΔY / ΔT can be obtained.

In this embodiment using the gyroscope 41 and the vehicle speed sensor 22 in order to detect the detection values ω and V used for calculating the lateral G, ΔG / ΔT, and ΔY / ΔT, The same effect as that of the embodiment can be obtained.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described. In each of the above embodiments, the lateral G change rate ΔG / ΔT is calculated by the equation ΔG / ΔT = V ² · Δ
(1 / r) / ΔT or the equation ΔG / ΔT = V · Δω
The vehicle speed V was calculated as being constant using / ΔT. On the other hand, in this embodiment, a change in the vehicle speed V is considered. Except that the formula for calculating the lateral G change rate ΔG / ΔT is different,
The configuration is the same as that of each of the above embodiments.

First, in the first and second embodiments having the tire angle sensor 21 and the vehicle speed sensor 22 as detectors, the case where the time change of the vehicle speed V is considered in the lateral G change rate ΔG / ΔT will be described. . This is performed based on, for example, the above-described equation (3) in which the time change of the vehicle speed V is considered, instead of the equation (2). That is, the following equation.

ΔG / ΔT = V ² Δ (1 / r) / ΔT + (1 / r) 2 VΔV / ΔT (3) The ROM 32 calculates the lateral G change rate ΔG based on the equation (3). The following equation is stored as the equation to be performed.

ΔG / ΔT = V ² · | 1 / r-1 / r1 |
+ (1 / r) · 2V · | V−V1 | Here, V1 and V are vehicle speeds before and after a predetermined time ΔT (= n · ΔTo) elapses. 1 / r1 and 1 / r are reciprocal values of the turning radii obtained by using the maps from the tire angles θ1 and θ before and after the lapse of the predetermined time ΔT, respectively. C
In the present embodiment, the PU 31 stores the tire angle data θ and the vehicle speed data V for a plurality of past times in the RAM 32.

The following equation (4) can also be used as the equation for calculating the lateral G change rate ΔG / ΔT. ΔG / ΔT = Δ (V ² / r) / ΔT (4) The lateral G change rate ΔG / Δ is stored in the ROM 32 based on the equation (4).
The following equation is stored as an equation for calculating T.

ΔG / ΔT = | Gs−Gs1 | (= | V ² /
r-V1 ² / r1 | In) where, Gs1, Gs is the lateral G data before and after the lapse of a predetermined time ^{ΔT, Gs1 = V1 2 / r1} , Gs = V 2
/ R. Here, V1, r1 and V, r are the vehicle speed and the turning radius before and after the predetermined time ΔT has elapsed, respectively. The CPU 31 stores a plurality of past horizontal G data Gs in the RAM 32. In addition, the detected value V of the vehicle speed before the difference calculation process is subjected to software-based filter processing by the CPU 31 so that the calculated value of the lateral G change rate is not significantly affected by noise that is amplified at the time of the difference calculation of the vehicle speed V. ing.

The CPU 31 outputs the current data V, 1 / r
Then, ΔG / ΔT is calculated using a calculation formula based on the formula (3) or (4) using the old data V1 and 1 / r1 before the predetermined time ΔT. According to this embodiment,
Since the lateral G change rate ΔG / ΔT is used in consideration of the time change of the vehicle speed calculated based on the equation (3) or the equation (4), such as during acceleration or deceleration (for example, during braking) Even when the time change of the vehicle speed V cannot be ignored, an accurate ΔG
/ ΔT value can be obtained. Therefore, even when the vehicle speed changes, the rear axle 10 is locked only when it is really necessary, and unnecessary lock can be avoided as much as possible.

Next, a description will be given of a case where the time change of the vehicle speed V is considered in the lateral G change rate ΔG / ΔT in the configuration of the third embodiment having the vehicle speed sensor 22 and the gyroscope 41 as detectors. Instead of the equation ΔG / ΔT = V · Δω / ΔT, one of the following equations taking into account the time change of the vehicle speed V is adopted.

ΔG / ΔT = V · Δω / ΔT + ω · ΔV / ΔT (5) ΔG / ΔT = Δ (V · ω) / ΔT (6) When the equation (5) is adopted, the ROM 32 has As a formula for calculating the G change rate ΔG / ΔT, the formula ΔG / ΔT = ω · | V−
V1 | + V · | ω−ω1 | is stored. Also,
When the equation (6) is adopted, the ROM 32 stores the equation ΔG / ΔT = | V · ω− as the equation for calculating the lateral G change rate ΔG / ΔT.
V1 · ω1 | is stored. Here, V1, ω1 and V, ω are the vehicle speed and the yaw rate before and after the predetermined time ΔT has elapsed, respectively. In this case as well, the detected value V of the vehicle speed is subjected to software-based filter processing by the CPU 31. The CPU 31 calculates the current data V, ω,
Using the old data V1 and ω1 before the predetermined time ΔT,
Using a calculation formula based on the formula (5) or (6), Δ
G / ΔT is calculated.

According to this embodiment, by using the lateral G change rate ΔG / ΔT in which the time change of the vehicle speed calculated using the equation (5) or (6) is taken into account, the acceleration or deceleration can be achieved. Even when the time change of the vehicle speed V cannot be ignored, such as at the time of braking (for example, during braking), it is possible to obtain an accurate ΔG / ΔT value. As a result, even when the vehicle speed changes, the rear axle 10 can be locked when it is really needed, and unnecessary lock can be avoided.

The present invention is not limited to the above embodiments, but may be modified as appropriate without departing from the spirit of the invention, and may be embodied as follows, for example. (1) Transverse G change rate ΔG / Δ regardless of vehicle speed range
In the first embodiment using T, the third detector
A configuration in which the vehicle speed sensor 22 and the gyroscope 41 used in the embodiment are combined may be employed. That is, using the detected value ω of the gyroscope 41 and the vehicle speed value V, the lateral G change rate ΔG / ΔT = V · Δω / ΔT, lateral G; Gs = V
・ Calculate ω. With this configuration, the same effect as in the first embodiment can be obtained. That is, the effect of preventing the delay of the lock of the rear axle at the start of turning, the effect of holding the lock of the rear axle during the switching operation, and the lateral G change rate ΔG / ΔT (= V · Δω / ΔT) having the vehicle speed V as a factor. By adopting this, an effect of avoiding unnecessary lock can be obtained.

(2) In the first embodiment, the lateral G is detected by the acceleration sensor, and the lateral G change rate ΔG / ΔT is calculated by time difference of the detected value of the acceleration sensor, thereby controlling the axle oscillation. A configuration may be made based on the lateral G and ΔG / ΔT. Also with this configuration, it is possible to prevent delay in regulation of the axle swing at the start of turning, and to maintain the axle in the swing regulation state during switching of the steering wheel. In this case, ΔG
/ ΔT can set an appropriate set value common to the level of the vehicle speed. Therefore, useless locking of the rear axle in the low speed range can be reduced.

(3) The detection value used for calculating the judgment value is not limited to the above embodiments. For example, instead of the tire angle sensor 21, a steering wheel angle sensor for detecting the rotation angle of the steering wheel 12 is used, and the reciprocal value 1 / r of the turning radius is obtained from the steering wheel angle θH, so that each determination value Gs,
A method of calculating ΔG / ΔT and ΔY / ΔT may be adopted.

(4) The lateral G is detected by the acceleration sensor, and the lateral G is detected.
Change rate ΔG / ΔT or yaw rate change rate ΔY / ΔT
May be estimated from the detected values from the steering angle detector and the vehicle speed detector, or from the detected values from the yaw rate detector and the vehicle speed detector. According to this configuration, when the detection value of the acceleration sensor is subjected to the difference (differential) processing, the noise is amplified and the determination values (ΔG / ΔT, ΔY
/ ΔT) becomes less reliable. To avoid this,
Since the detection value from the detector that is difficult to pick up noise such as vibration is subjected to difference processing, a highly reliable determination value can be obtained.

(5) The calculation formula for estimating the determination value ΔY / ΔT may be a formula that takes into account the time change of the vehicle speed. For example, when the configuration of the second embodiment using the tire angle sensor 21 and the vehicle speed sensor 22 or the configuration of the fourth embodiment is adopted in the second embodiment, ΔY / ΔT = V · Δ (1
/ R) / ΔT + 1 / r · ΔV / ΔT, ΔY / ΔT = Δ
(V / r) / ΔT may be adopted. When these formulas are employed, an accurate ΔY / ΔT can be obtained even when the vehicle speed changes, and even at a low speed, the rear axle 10 can be locked when it is really needed, and unnecessary locking can be avoided.

(6) Noise removal processing such as applying a low-pass filter to the detection value from each sensor or the determination value calculated using the detection value may be performed. (7) The method of detecting the tire angle θ is not limited to the method of detecting the amount of rotation of the king pin 20. For example, a detector that detects the position of a piston of a steering cylinder included in the power steering device may be employed as the tire angle sensor.

(8) The types of detectors for detecting each detection value used for calculating the determination value are not limited to two types. For example, the determination value may be estimated using each detection value obtained from three or more detectors having different detection targets.

(9) The regulation of the swing of the axle is not limited to the lock for completely fixing the axle. The regulation may be such that the swing range becomes narrower in the regulated state of the axle.
The effects of the present invention can be obtained if the swing range is reduced during the regulation of the axle.

(10) The present invention may be applied to a battery type forklift. Further, the present invention may be applied to industrial vehicles other than forklifts. Grasped from the above embodiments are listed in hereinafter the technical concept that is not described (invention) in the appended claims.

[0107] (i) pre-Symbol axle restricting mechanism, fixed a hydraulic damper which is connected to said vehicle body and an axle, and a permitting position for permitting the expansion and contraction motion of the hydraulic damper, the telescopic movement of the hydraulic damper A switching valve that can be switched to at least two positions with respect to a fixed position. The control means controls the switching of the switching valve based on the measured values .

[0108] (b) pre-Symbol measurement value calculating means, the rate of change with time of the reciprocal of the turning radius uniquely determined from the detection value is the steering angle of the steering angle detector, as the product of the square of the vehicle speed The lateral G change rate is calculated .

[0109] (c) before Symbol measurement value calculating means calculates the lateral G change rate as the product of the change rate and the vehicle speed with respect to time of the a detection value of the yaw rate detector yaw.

[0110] (d) comprises a center-of-gravity height measuring means for measuring the height of the center of gravity of the vehicles, the set value of the lateral G in response to centroid height measured by the height of the center of gravity measuring device are determined.
According to this configuration, the set value of the lateral G changes according to the height of the center of gravity of the vehicle measured by the center-of-gravity height measuring means, so that unnecessary regulation of axle swing can be reduced. The center-of-gravity height measuring means includes the lift sensor 23, the pressure sensor 24, and the CPU 31 in each of the above embodiments.

[0111] a filter means for filtering prior to use in advance of the lateral G change rate calculating a detection value of (e) prior Symbol vehicle speed is provided. According to this configuration, the lateral G change rate is calculated using the detected value of the vehicle speed from which the noise has been removed by the filter processing by the filter processing means, and the noise that is amplified during the difference calculation processing in calculating the lateral G change rate is calculated. Is removed beforehand as much as possible before the calculation processing, so that a highly accurate calculated value of the lateral G change rate with little influence of noise can be obtained.
Note that the CPU 31 constitutes a filter unit.

[0112]

As described in detail above, according to the invention described in each claim, the lateral G change rate is used as a measured value other than the lateral G for determining whether or not the axle swing should be restricted. Therefore, the swing of the axle can be restricted quickly at the start of turning, and the axle can be held in the swing restricted state at the time of switching. Also, since the lateral G change rate is a measured value in which the factor of the vehicle speed is taken into consideration, an appropriate set value common to high and low vehicle speeds can be set, and the yaw rate change rate in which the factor of the vehicle speed is not taken into account is used for the determination. Unnecessary axle regulation can be reduced as much as possible.

In particular, according to the first aspect of the present invention, when the vehicle speed is in a low speed range less than the set value, the lateral G change rate is used to determine whether or not the swing of the axle should be restricted. Since the yaw rate change rate is employed, even in a low-speed range where the vehicle speed is low, useless regulation of the axle swing can be suppressed, and the axle swing can be reliably regulated when necessary.

[0114] According to the invention described in claim 2, 5, 6, by calculation using the respective detected values of the two or more detectors with different detection target provided in the vehicle, the axle swinging Since each measurement value used for determining whether or not to restrict the movement is calculated, necessary measurement values can be obtained without providing an acceleration detector for directly detecting the lateral G.

[0115] According to the invention described in claim 3, the lateral
When calculating the rate of change of G or the rate of change of yaw rate,
Since the detected values of the two detectors, which are hard to pick up vibration, are compared,
No need to worry about noise amplification due to minute (derivative)
High measurement values can be obtained. Claim 4 and the contract
According to the invention described in claim 6, the detection value of each detector is a variable
Time derivative of the theoretical formula for calculating the lateral G
And the time derivative of vehicle speed is not neglected.
Since the output lateral G change rate is used as a measured value, the vehicle speed
Limit axle swing at the appropriate time to respond to changes
Can be.

[0116] According to the invention described in claim 5, the lateral
Detector that hardly picks up vehicle vibration when calculating G change rate
The difference between the detected values of
Obtain reliable measurements without worrying about amplification
Wear.

[0117] According to the invention described in claim 7, pressurized
Even without a speed detector, the steering angle detection provided on the vehicle
By calculation using each detection value from the output unit and the vehicle speed detector,
Each required measurement can be estimated.

[0118] According to the invention described in claim 8, pressurized
Even without a speed detector, the yaw
Calculation using the detected values from the speed detector and the vehicle speed detector.
Thus, each required measurement value can be estimated. Also, at low speeds
In the configuration that adopts the rate of change of rate, the axle
Because the swing is well regulated,
Minimize the roll of the vehicle body when stumbling on a projection
be able to.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing an axle regulating mechanism.

FIG. 3 is a side view of the forklift.

FIG. 4 is a block diagram showing an electric configuration of the vehicle body swing control device.

FIG. 5 is a graph showing a change in a lateral G and a lateral G change rate during turning.

FIG. 6 is a map diagram showing a horizontal G lock region with respect to load and lift.

FIG. 7 is a flowchart of a swing control process.

FIG. 8 is also a flowchart.

FIG. 9 is a flowchart of a part of a swing control process according to the second embodiment;

FIG. 10 is a plan view of a forklift according to a third embodiment.

FIG. 11 is a block diagram showing an electrical configuration of the vehicle body swing control device.

FIG. 12 is a flowchart of a part of a swing control process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Forklift as an industrial vehicle, 1a ... Body frame as a vehicle body, 10 ... Rear axle as an axle,
13: a hydraulic damper constituting the axle regulating mechanism; 14: an electromagnetic switching valve constituting the axle regulating mechanism and a switching valve; 21 ... constituting the lateral G measuring means, lateral G change measuring means and yaw rate change measuring means A tire angle sensor 22 serving as a steering angle detector; a vehicle speed sensor 22 serving as a vehicle speed detecting device and a vehicle speed detecting device, comprising lateral G measuring device, lateral G change measuring device, and yaw rate change measuring device;
Reference numeral 3 denotes a lift sensor constituting the center of gravity height measuring means, 24 a pressure sensor constituting the center of gravity height measuring means, 25 a controller as control means, 31 ... a lateral G measuring means, a lateral G change measuring means and a yaw rate change measuring means. A gyroscope constituting a lateral G measuring means, a lateral G change measuring means and a yaw rate change measuring means, and a gyroscope as a yaw rate detector; … Horizontal G, ΔG / Δ
T: lateral G change rate, ΔY / ΔT: yaw rate change rate.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 17/005 B60G 9/02 B60R 21/13

Claims (8)

(57) [Claims] An axle supported so as to be capable of swinging with respect to a vehicle body of the vehicle, an axle regulating mechanism for regulating swinging of the axle, a lateral G measuring means for measuring a lateral G of the vehicle, A lateral G change measuring means for measuring a rate of change of the lateral G with respect to time; and when any one of the measured values of the lateral G and the lateral G change rate is equal to or more than a respective set value, the swing of the axle is regulated. Means for operating the axle regulating mechanism, and a yaw for measuring a rate of change of the yaw rate of the vehicle with respect to time.
Rate change measuring means, and vehicle speed detecting means for detecting a vehicle speed, wherein the control means determines whether or not the vehicle speed is less than a set value.
The vehicle speed is set to a set value.
When the vehicle is in a low-speed range of less than
Using the yaw rate change rate as a measured value,
And either of the yaw rate change rates is greater than each set value
Then, the axle regulating device is used to regulate the swing of the axle.
A body swing control device for an industrial vehicle that operates a structure . 2. The vehicle has two or more different detection targets.
And two detectors detected by each detector are provided.
By the calculation using the above detected values, the swing of the axle is regulated.
Calculate each of the above measured values to determine whether to control
2. A measurement value calculating means provided in each of said measuring means.
3. The vehicle body swing control device for an industrial vehicle according to claim 1. 3. The measured value calculating means according to claim 1 , wherein
When calculating the lateral G change rate or the yaw rate change rate
Of the detectors, one of the detectors that is hard to pick up the vibration of the vehicle
The vehicle body swing of an industrial vehicle according to claim 2, wherein the detected value is subtracted.
Control device. 4. The vehicle speed as one of the two or more detectors.
A detector is provided, and the measurement value calculating unit is configured to determine the measurement value.
Change the lateral G change rate by two or more detection values of the detectors.
Time derivative of the theoretical formula for calculating the lateral G of a number
Calculated using a formula that does not ignore the time derivative term of vehicle speed.
The vehicle body swing control device for an industrial vehicle according to claim 2. 5. A vehicle swingably supported by a vehicle body.
Axle, an axle regulating mechanism for regulating swing of the axle, a lateral G measuring means for measuring a lateral G of the vehicle, and a lateral G change measurement for measuring a rate of change of the lateral G with respect to time.
Means, and each of the measured values of the lateral G and the lateral G change rate is
Above the set value of the axle
Control means for operating the axle regulating mechanism, wherein the vehicle is provided with two or more detectors different in detection target.
And two or more detection values detected by each detector
Whether the axle swing should be regulated by the calculation used
Measurement value calculation means for calculating the respective measurement values for the determination of
And the measurement value calculation means.
When calculating the lateral G change rate among the measured values,
Detected value of detectors that are difficult to pick up vehicle vibration
The vehicle body swing control device for an industrial vehicle that calculates 6. A swingably supported body of a vehicle.
Axle, an axle regulating mechanism for regulating swing of the axle, a lateral G measuring means for measuring a lateral G of the vehicle, and a lateral G change measurement for measuring a rate of change of the lateral G with respect to time.
Means, and each of the measured values of the lateral G and the lateral G change rate is
Above the set value of the axle
Control means for operating the axle regulating mechanism, wherein the vehicle is provided with two or more detectors different in detection target.
And two or more detection values detected by each detector
Whether the axle swing should be regulated by the calculation used
Measurement value calculation means for calculating the respective measurement values for the determination of
Is provided in each of the measurement means, and two or more of the detection
A vehicle speed detector as one of the detectors;
Is the lateral G change rate as the measured value, two or more of the
Theory for calculating the lateral G with the detection value of the detector as a variable
Time derivative of the equation, and ignore the time derivative term of the vehicle speed.
Body swing control system for industrial vehicles calculated using a simple calculation formula
Place. 7. The vehicle according to claim 1 , wherein the detector is a steering wheel.
Steering angle detector for detecting steering angle and vehicle speed for detecting vehicle speed
A detector, and the measured value calculating means includes a steering angle and a vehicle speed.
The two measured values are used to calculate each of the measured values.
Body rocking industrial vehicle according to an item of claims 6 sac Chiizure
Motion control device. 8. The vehicle according to claim 1 , wherein the detector is a vehicle body support.
Yaw rate detector that detects the vehicle speed and vehicle speed
A vehicle speed detector.
Calculate the measured values using both the detected values of the speed and the vehicle speed.
The industrial vehicle according to any one of claims 2 to 6.
Both body swing control devices.