JPH10226211A - Device for controlling rocking of industrial vehicle body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce more regulation of the rocking of an axle than required in a device regulating the rocking of an axle in accordance with the height of the center of gravity of a vehicle. SOLUTION: A rear axle 10 carrying rear wheels 11 is provided as to allow it to pivot on a center pin 10a against a body frame, and connected at its end to the body frame via a damper 13. A controller 25 uses the values θ and V detected respectively by a wheel angle sensor 21 and a vehicle speed sensor 22 to calculate the lateral gravity applied to a vehicle body, and switches over a solenoid operated selector valve 14 to lock the damper 13 when the lateral gravity exceeds the specified value. The specified value for the lateral gravity G is so determined, from the lift H detected by a lift sensor 23 and the load W detected by a pressure sensor 24, as to correspond step by step to the height of the center of gravity of vehicles, using a map.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body swing control device for an industrial vehicle which fixes an axle swingably provided on the vehicle body at a required time in order to secure the running stability of the industrial vehicle. .

[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. However, at the time of turning, the vehicle body may be tilted by receiving a lateral force due to centrifugal force, so that running stability may be rather deteriorated.

Japanese Patent Laid-Open Publication No. Sho 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, since the axle is fixed, the inclination of the vehicle body at the time of turning can be suppressed small, and the turning can be performed in a stable posture.

Japanese Unexamined Patent Application Publication No. 58-167215 discloses a heavy load detecting means for detecting that the load of a load on a fork has exceeded a predetermined weight, and a method for detecting that the fork has risen to a predetermined height or more. Uplift detecting means for detecting
A technique is disclosed in which the axle is locked when both detection means are in the detection state. According to this technique, when the center of gravity of the vehicle is relatively unstable due to heavy load and high elevation, the axle is locked, so that the vehicle can turn in a stable posture.

[0005]

Problems to be Solved by the Invention
According to the technique disclosed in Japanese Patent Application Laid-Open No. 15, the axle is always locked when the load is high and the lift is high.
Was taken into account. Therefore, the height of the center of gravity that locks the axle (set value considered as high load and high lift), assuming the most severe situation such as when making a sharp turn at high speed running
Had to be set lower. Therefore, if the height of the center of gravity is a certain height equal to or higher than the set value, the axle is locked even when the lateral G is small and the axle need not be locked.

Accordingly, the applicant of the present application has disclosed Japanese Patent Application Laid-Open No. 58-21 / 1983.
A configuration has been proposed in which a turning detection means such as the technique of 1903 is additionally provided and the lateral G is taken into consideration. Since the axle locks when the lateral G exceeds a certain value, the set value (center of gravity height) regarded as high load and high lift can be set as high as possible, and unnecessary locking of the axle can be prevented as much as possible. Can be reduced.

However, in this device, since the axle is locked when the lateral G exceeds a certain value, a severe case where the height of the center of gravity is highest within a range where the height of the center of gravity is less than a set value is assumed. Had to be set small. Therefore,
Even when the height of the center of gravity in which the lateral G is considered is within the range of less than the set value, if the height of the center of gravity is relatively low, the problem that the axle is locked unnecessarily still remains.

If the axle is locked unnecessarily, the running stability which must be ensured by swinging of the axle is impaired. Further, when the axle is locked while the vehicle weight is on the rear wheel side while traveling on an uneven road surface, one side of the front wheel, which is a drive wheel, may rise, and the ground pressure of the drive wheel may be raised. Slip is likely to occur due to a decrease in for that reason,
It is required not to lock the axle unnecessarily.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to provide an axle that does not require an axle in a configuration in which axle swing control is performed in accordance with the height of the center of gravity of the vehicle. It is an object of the present invention to provide a vehicle body swing control device for an industrial vehicle, which can reduce various swing regulations. The second purpose is
The purpose of the present invention is to determine the set value of the horizontal G only by performing a comparison determination process on both the detected values of the lift detector and the load detector, respectively, with a comparison value. A third object of the present invention is to set the set value of the lateral G by continuously changing the set value according to the height of the center of gravity so that an appropriate set value can be finely picked up and further reduce unnecessary swing regulation of the axle.

[0010]

In order to achieve the first object, according to the first aspect of the present invention, an axle supported to be vertically swingable with respect to a vehicle body, and a swing of the axle is provided. An axle regulating mechanism for regulating the vehicle, lateral G detecting means for detecting the lateral G of the vehicle, a gravity center height detecting means for directly or indirectly detecting the height of the center of gravity of the vehicle, A set value corresponding to the height of the center of gravity of the vehicle detected by the center-of-gravity height detecting means is selected from the set values set continuously or continuously, and the lateral G detected by the side-G detecting means is selected. And control means for operating the axle regulating mechanism to regulate the axle swing when the set value is equal to or more than the set value.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a yaw rate change detecting means for detecting a rate of change of the yaw rate of the vehicle with respect to time, and the control means is provided with the yaw rate change detecting means. Even when the detected rate of change of the yaw rate becomes equal to or greater than a preset value, the axle restricting mechanism is operated to restrict the axle from swinging.

According to a third aspect of the present invention, in the first or second aspect of the invention, the center-of-gravity height detecting means detects a height of a loading device provided to load a vehicle. Height detector, and a load detector for detecting the load of the load on the loading equipment, the control means, from among the set values set in advance, to both the detected values of the height and load The setting value is determined based on the center of gravity of the vehicle based on the set value.

According to a fourth aspect of the present invention, in order to achieve the second object, in the third aspect of the invention, a plurality of the preset values are set discontinuously with respect to the lift and the load. Have been.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, at least one of the lift detector and the load detector is a switch type detector. In order to achieve a third object, in the invention described in claim 6, in the invention described in claim 3, at least one of the lift detector and the load detector can detect a continuous change. Wherein the preset value set in advance with respect to the detection value detected by the detector is continuously changed.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the height detector is a detector capable of detecting a continuous change in the height, and the preset value is a predetermined value. It is set to change continuously with the height.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the load detector is a detector capable of detecting a continuous change in the load, and the preset value is set with respect to the load. It is set to change continuously.

According to a ninth aspect of the present invention, in the invention of the sixth aspect, both the lift detector and the load detector are detectors capable of detecting continuous changes in the lift and the load, respectively. The preset value is set so as to continuously change with respect to both the detected values of the lift and the load.

According to the first aspect of the invention, the lateral G of the vehicle is detected by the lateral G detecting means, and the height of the center of gravity of the vehicle is directly or indirectly detected by the height detecting means. Is done. The control means selects a set value corresponding to the height of the center of gravity detected by the center of gravity height detection means from among the set values which are set in advance discontinuously or continuously with respect to the height of the center of gravity. Then, when the lateral G becomes equal to or more than the selected set value, the axle restricting mechanism is operated to restrict the axle from swinging. The set value of the lateral G used for the axle swing regulation control by the control means changes according to the height of the center of gravity from among the set values prepared in advance, and the set value of the lateral G changes according to the height of the center of gravity at the time. Since an appropriate value is adopted, unnecessary swing regulation of the axle is reduced.

According to the second aspect of the present invention, the yaw rate change rate of the vehicle is detected by the yaw rate change rate detecting means. The control means operates the axle restricting mechanism to restrict the axle from swinging even when the rate of change of the yaw rate detected by the rate of change of the yaw rate is equal to or greater than the set value. Therefore, the swing of the axle is restricted early at the start of turning of the steering wheel, and the regulation of the swing of the axle is prevented from being released during the turning of the steering wheel when changing the turning direction of the vehicle.

According to the third aspect of the present invention, the lift of the loading equipment is detected by the lift detector, and the load on the loading equipment is detected by the load detector. Then, the set value of the lateral G corresponding to the height of the center of gravity of the vehicle is determined from the set values set in advance based on the detected values of the lift and the load. That is, the set value of the lateral G according to the height of the center of gravity of the vehicle is obtained indirectly from both the detected values of the lift and the load.

According to the fourth aspect of the present invention, the predetermined number (plurality) of preset values are set discontinuously with respect to the lift and the load. As a process for determining the required set value of the lateral G from the detected values of the above, a comparison determination process of comparing the detected values of the lift and the load with a preset comparison value can be adopted. Necessary setting values can be determined from a plurality of setting values. Therefore, complicated calculations, maps, and the like for obtaining necessary setting values using the detected values of the lift and the load become unnecessary.

According to the fifth aspect of the present invention, since the detector provided in at least one of the elevation detector and the load detector is a switch type detector, an AD conversion circuit or the like is unnecessary, and the The configuration is simple and the control is simple.

According to the invention described in claim 6, the preset set value changes continuously with respect to the detected value of the detector capable of detecting a continuous change among the height detector and the load detector. Is set. Therefore, a more appropriate set value of the lateral G according to the continuously changing detection value of at least one of the lift and the load is adopted, and unnecessary swing regulation of the axle is further reduced.

According to the seventh aspect of the invention, the preset value is set so as to be continuously changed with respect to the height continuously detected by the height detector. For this reason, the set value of the lateral G according to the height of the center of gravity of the vehicle is more finely and appropriately determined according to the height at each time, and unnecessary swing regulation of the axle is further reduced.

According to the eighth aspect of the present invention, the preset set value is set to be continuously changed with respect to the load continuously detected by the load detector. Therefore, the set value of the lateral G is finely and appropriately determined according to the load at that time, and unnecessary swing regulation of the axle is further reduced.

According to the ninth aspect of the present invention, the preset value is a continuous value between the lift continuously detected by the lift detector and the load continuously detected by the load detector. To be set. Therefore, the set value of the lateral G is almost optimally determined according to the height and load at that time,
Unnecessary swing regulation of the axle is further reduced.

[0027]

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 shown in FIG. 3 is a front-wheel drive and rear-wheel steering four-wheeled vehicle. An inner mast 3 is disposed 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.
Is suspended via a chain (not shown) so as to be able to move up and down. The outer mast 2 is a body frame 1a as a body.
Are connected via a tilt cylinder 5 to the
When the piston rod 5a of the tilt cylinder 5 is driven to expand and contract, it tilts. A piston rod 6a of a lift cylinder 6 disposed on the back surface of the outer mast 2 is connected to an upper end of the inner mast 3,
When the piston rod 6a of the lift cylinder 6 is driven to expand and contract, the fork 4 moves up and down. 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 FIG. 1 and FIG.
A rear axle 10 as an axle is supported at the rear lower part of the rear part a so as to be vertically swingable (rotatable) around a center pin 10a while extending in the vehicle width direction. Left and right rear wheels 11
Are steerably connected to each end of a pair of left and right piston rods of a steering cylinder (not shown) disposed on the rear axle 10 via a link mechanism (not shown). It is supported so as to be able to swing together. The left and right rear wheels 11 are steered by driving the steering cylinder based on the operation of the steering wheel 12.

As shown in FIG. 2, one hydraulic damper (hereinafter simply referred to as "damper") 13 is disposed between the vehicle body frame 1a and the rear axle 10 so as to connect them. ing. The damper 13 is a double-acting hydraulic cylinder. The cylinder 13a of the damper 13 is connected to the vehicle body frame 1a, and the tip of a piston rod 13c extending from a piston 13b housed in the cylinder 13a is connected to the rear axle 10 side. It is connected to.

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

When the spool of the electromagnetic switching valve 14 is disposed at the shut-off position shown in FIG. 2 with respect to the body, the damper 13 is in a locked state in which the outflow and inflow of the hydraulic oil in both chambers R1 and R2 is impossible. The swing of the axle 10 is locked. On the other hand, when the spool of the electromagnetic switching valve 14 is disposed at the communication position with the body (the state where the spool position is switched to the opposite side from the state of FIG. 2), the damper 13 operates between the two chambers R1 and R2. The oil is in a free state in which the outflow / inflow of the oil is possible, and the swing of the rear axle 10 is allowed. Further, a throttle valve 19 is provided on the path of the second pipeline P2. The axle regulating 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 a king pin 20 that rotatably supports the rear wheel 11, the amount of rotation of the king pin 20 is detected and the steering angle (tire angle) of the rear wheel 11 is detected.
A tire angle sensor 21 for detecting θ is provided. The tire angle sensor 21 includes, for example, a potentiometer.
As shown in FIG. 1, the differential ring gear 8 is provided with a vehicle speed sensor 22 for detecting the rotation of the differential ring gear 8 to detect the vehicle speed V of the forklift 1. Note that the tire angle sensor 21 and the vehicle speed sensor 22 constitute a lateral G detecting unit and a yaw rate change detecting unit.

As shown in FIGS. 1 and 3, on the upper end of the outer mast 2, a lift sensor 23 composed of a lift detector and a limit switch as a switch type detector is mounted. The lift sensor 23 is set to turn on when the lift of the fork 4 exceeds the set value ho, and to turn off when the fork 4 is less than the set value ho. In the present embodiment, the set value ho is set to be approximately half the maximum lift height hmax.
The lift cylinder 6 is provided with a pressure sensor 24 as a load detector for detecting the oil pressure inside the lift cylinder. The pressure sensor 24 outputs a detection value w corresponding to the load on the fork 4. As shown in FIG. 1, a solenoid 14a provided in the electromagnetic switching valve 14 and each of the sensors 21 to 24 are electrically connected to a controller 25 as control means. The lift sensor 23 and the pressure sensor 24 constitute a part of the center of gravity height detecting means.

Next, the electrical configuration of the forklift 1 will be described with reference to FIG. A controller 25 for swing control, which will be described later, provided in the forklift 1 includes a microcomputer 26 and AD conversion circuits 27 to 2.
9 and an excitation / demagnetization drive circuit 30 are incorporated. The microcomputer 26 constitutes a horizontal G detecting means and a yaw rate change detecting means and has a CPU (central processing unit) 31, a ROM (read only memory) 32, a RAM (read / write memory) 33, a clock circuit 34, a counter, and the like. 35, 36, an input interface 37 and an output interface 38.

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. The solenoid 14a is C
The PU 31 is excited / demagnetized based on a control signal output via the excitation / demagnetization drive circuit 30. That is, the electromagnetic switching valve 1
The solenoid 4a is switched to the cut-off position by demagnetizing the solenoid 14a based on the disappearance of the unlock signal, and is controlled based on the output of the unlock signal.
Is switched to the communication position by being excited.

The ROM 32 stores various program data including the program data of the swing control processing shown in the flowcharts of FIGS. Here, the swing control is a control for locking the rear axle 10 and restricting the swing of the rear axle 10 in order to maintain running stability at a predetermined time set in advance. In the present embodiment, the predetermined time is determined by detecting a lateral G (centrifugal acceleration acting in the lateral direction of the machine when turning) Gs acting on the vehicle and a rate of change of the yaw rate with respect to time (yaw rate change rate) ΔY over time.
, ΔY value is set to be equal to or more than each set value, and the rear axle 10 is set to be locked at this time. Note that in the flowcharts of FIGS. 7 and 8, S10 to S30 constitute the horizontal G detecting means,
10, S20 and S40 constitute a yaw rate change detecting means.

In this embodiment, the set value of the horizontal G (Gs) is
As shown in FIGS. 6A and 6B, the values are set for each combination of the load w and the height H, which indirectly detect the height of the center of gravity of the vehicle. That is, as shown in FIG. 6 (a), when the load w is less than the set value w0, "G2" when the lift H is less than ho, and "G1" when the lift H is more than ho.
(In the present embodiment, G1 = G2 / 2).
Further, as shown in FIG. 6B, when the load w is equal to or more than the set value w0, when the lift H is less than ho, the value becomes "G2".
It is set to “0” so that the rear axle 10 is always locked when the lift H is equal to or greater than ho. That is, two values G1 and G2 are prepared as the set values of the lateral G used when the height is not high (H ≧ ho) and the load is not high (w ≧ wo).

The ROM 32 stores a set value yo of the yaw rate change rate ΔY. Each set value G1, G
2, yo is a value obtained from a driving experiment or a theoretical calculation so that the rear axle 10 is locked at a necessary time when driving stability can be achieved. The CPU 31 has two flags Fg and Fy. The flag Fg is set when the horizontal G (Gs) exceeds the set value G1 or G2, and the flag Fy is set when the yaw rate change rate ΔY exceeds the set value yo.

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 calculated 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 yaw rate change rate ΔY is given by the following equation (2) using two detected values θ and V.

ΔY = V · Δ (1 / r) / ΔT (2) where Δ (1 / r) is a predetermined time ΔT (for example, several tens of milliseconds) of the reciprocal value 1 / r of the turning radius. Is the amount of change (deviation). The deviation Δ (1 / r) is calculated from the tire angle data θ of a plurality of past times (the predetermined time ΔT is taken as one) stored in the RAM 33 and the tire angle data θ before the predetermined time ΔT.
1 is read out, and the reciprocal value 1 / r1 of the turning radius determined from the data θ1 is used, Δ (1 / r) = | 1 / r−1 / r1
|. The reciprocal value of the turning radius 1 / r
Takes a negative value when the tire angle θ is the left turning angle and a positive value when the tire angle θ is the right turning angle.

Incidentally, the yaw rate change rate ΔY (= Δω)
/ ΔT) is expressed by the following equation by differentiating this equation with time since the yaw rate ω is expressed by the equation ω = V / r. ΔY = V · Δ (1 / r) / ΔT + ΔV / ΔT · (1 / r) (3) During the turning of the forklift 1, the vehicle speed V at the time ΔT can be regarded as substantially constant. Expression (2), which is approximated ignoring the latter term, is employed as an arithmetic expression for estimating ΔY.

In this embodiment, when the flag Fy is "1", the set value for .DELTA.Y is ".alpha..yo", which is slightly smaller than "yo", and when the flag Fg is "1", the set value for Gs is set. The set values “α · wo” and “α · ho” that are slightly smaller than “wo” and “ho” (for example,
0.5 <α <1).
This is because, after the rear axle 10 is once locked, the set value is set slightly smaller so that the respective judgment values w,
This is a measure for preventing frequent switching between lock and unlock due to H and ΔY taking values near the initial set value at the time of locking.

The release of the lock is determined by the judgment values Gs, Δ
It is set so that the lock release condition is satisfied when Y becomes less than the set values G1, G2, yo after a predetermined time T has elapsed. The two counters 35 and 36 are for counting the duration of the satisfaction of the unlock condition.

Next, the swing control of the forklift 1 will be described with reference to the flowcharts of FIGS. While the ignition key is on, the CPU 31 receives detection signals θ, V, w, and on / off (see FIG. 4) from the sensors 21 to 24. The CPU 31 executes the swing control process at predetermined time intervals (for example, 10 to 50 milliseconds) using the detected values θ, V, w, and the like.

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 angle θ using the map stored in the ROM 32.

In step 30, the estimated value Gs of the lateral G is calculated from the vehicle speed V and the reciprocal value 1 / r of the turning radius by using equation (1). In step 40, the yaw rate change rate ΔY 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 determined from the data θ1 is used.
Calculate ΔY from equation (2) (where Δ (1 / r) = |
1 / r-1 / r1 |).

In step 50, it is determined whether or not ΔY is equal to or greater than the set value yo. If ΔY is equal to or greater than the set value yo, the routine proceeds to step 60, where "1" is set in the flag Fy. If ΔY is less than the set value yo, the process proceeds to step 70.

In step 70, the unlock condition (Fy
= 0, ΔY <yo, and Fy = 1, ΔY <α ·
It is determined whether or not yo) has been established for a predetermined time T. Each time ΔY ≧ yo is satisfied, the counter 35 is reset, so that the counter 35 measures the duration during which the lock release condition is satisfied. If the time measured by the counter 35 is less than the predetermined time T, the routine proceeds to step 90, where the flag F
No changes are made to y. On the other hand, if the time counted by the counter 35 is equal to or longer than the predetermined time T, the routine proceeds to step 80, where the flag Fy is set to "0". As described above, 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 or not the rear axle 10 should be locked based on the lateral G (Gs). In order to determine whether or not the rear axle 10 should be locked, the side G (G
s) Set value used for comparison with (G1, G2, etc.)
Is selected in accordance with the detected values of the load w and the lift H which indirectly represent the height of the center of gravity of the vehicle, as shown in FIGS. 6 (a) and 6 (b).

First, at step 90, the load w is set to the set value w.
o Determine if this is the case. If the load w is less than the set value wo, the process proceeds to step 100, where the load w is set to the set value wo.
If so, 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. If the lift H is less than the set value ho, it is determined in step 120 whether or not Gs ≧ G2 is satisfied. If 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 the lock condition of Gs ≧ G2 or Gs ≧ G1 is satisfied, the process proceeds to step 150, and the flag Fg is set to “1”. That is, if the load w is relatively light below the set value w o, when the lift H is relatively low below the set value ho, the larger set value G2 is adopted, and the lift H is higher than the set value ho. Is relatively high, the set value G1 (<G
2) is adopted.

In each step (S120, S130), the lock condition is not satisfied (that is, the lock release condition is satisfied).
If so, the process proceeds to step 160. In step 160, it is determined whether or not the lock release condition has been satisfied for a predetermined time T. The counter 36 is reset every time the lock condition is satisfied, and the counter 36 measures the duration of time in which the lock release condition is satisfied.

In step 160, if the time measured by the counter 36 is less than the predetermined time T, step 180
And the flag Fg is not changed. On the other hand, when the time counted by the counter 36 is equal to or longer than the predetermined time T, the routine proceeds to step 170, where "0" is set in the flag Fg. In this case as well, the lock is not released immediately when the lock release condition is satisfied, but the lock release is delayed by a predetermined time T.

On the other hand, if the load w is equal to or greater than the set value w0, it is determined in step 110 whether the height H is equal to or greater 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. That is, when a heavy load (w ≧ wo) and a high lift (H ≧ ho) and the center of gravity of the forklift 1 is higher than a predetermined value, the rear axle 10
Is locked.

When the lift H is less than the set value ho, the routine proceeds to step 140, where it is determined whether or not Gs ≧ G2 holds. That is, when the load w is relatively heavy above the set value w0 and the lift H is relatively low below the set value ho, the larger set value G2 (> G1) is adopted. When the lock condition Gs ≧ G2 is satisfied, at step 150, the flag Fg is set to "1".

If Gs ≧ G2 is not satisfied, that is, if the unlock condition (Gs <G2) is satisfied, step 16 is executed.
Then, it is determined whether or not the unlock condition has been satisfied for a predetermined time T, and if the unlock condition has been satisfied, the flag Fg is set to "0" in step 170,
If the lock release condition is not satisfied, the process proceeds to the next step 180 without changing the flag Fg.

In step 180, if any one of the flags Fy and Fg is "1", the output of the lock release command (lock release signal) is stopped. As a result, the horizontal G (Gs)
When any one of the yaw rate change rate ΔY and the yaw rate change rate exceeds the respective set value, the electromagnetic switching valve 14 is switched to the shut-off position, and the rear axle 10 is locked.

Here, in the present embodiment, the set value of the lateral G is changed based on both the detected values of the load w and the lift H, so that the set value of the lateral G to be adopted is changed stepwise according to the height of the center of gravity. I try to change it. Therefore, always rear axle 1
0 is locked and the heavy load (w ≧ wo) and the high lift (H ≧
In cases other than ho), the set value of the horizontal G is selected in two stages of G1 and G2 according to the height of the center of gravity at that time. That is,
In the present embodiment, an area sandwiched between G1 and G2 in the free area in FIG. 6 (that is, an area which is a lock area in the conventional configuration in which the set value of the horizontal G is constant) is
It will increase as a free area. Therefore, the rear axle 10 is relatively less likely to be locked more than necessary, as compared with the conventional configuration in which the set value of the lateral G is always constant.

Since unnecessary lock of the rear axle 10 is reduced, stable running by swinging of the rear axle 10 is further ensured. Further, since the rear axle 10 is locked when the vehicle is running on an uneven road surface with the rear wheel 11 under a heavy vehicle weight, one side of the front wheel 7, which is a driving wheel, rises from the road surface and the contact pressure thereof decreases. As a result, the occurrence of slips resulting from the above is relatively reduced.

FIG. 5 is a graph showing changes in the lateral G (Gs) and the yaw rate change rate ΔY during turning. For example, when the vehicle turns left from straight ahead during traveling, the rear axle 10 is locked early because the yaw rate change rate ΔY exceeds the set value yo before the lateral G reaches the set value. When the tire angle θ falls to a constant angle, the yaw rate change rate ΔY becomes less than the set value yo, but by this time the lateral G (Gs) has reached the set value or more, so the rear axle 1
0 is kept in a locked state during turning.

When the steering wheel 12 is turned from the left turn to the right turn, when the direction of the side G is switched from right to left, there is a section where the side G is momentarily less than the set value.
However, during the switching, the yaw rate change rate ΔY is equal to the set value y.
o The rear axle 10
Will not be unlocked. Further, since the unlocking of the rear axle 10 involves a delay of a predetermined time T from the establishment of the unlocking condition, the flag Fy = 1 and the flag Fg = 1
At the time of switching, the timing overlap that both become "1" is secured. For this reason, a slight shift in the timing of the change between the ΔY value and the Gs value causes
It is unlikely that the lock will be released during the turning of the vehicle.

Further, in this embodiment, the rear axle 1
After the lock of 0 has been executed once, the set value α at that time
The lock will not be released unless it falls below a slightly smaller set value. Therefore, the occurrence of frequent switching between lock and unlock due to the fact that each of the determination values ΔY, H, and w happens to take on values near the set values yo, ho, and wo is also prevented.

As described in detail above, according to the present embodiment,
The following effects can be obtained. (A) The set value of the lateral G used to determine whether to lock the rear axle 10 is changed stepwise according to the height of the center of gravity at that time based on the detected values of the load w and the lift H. As a result, unnecessary locking of the rear axle 10 can be reduced. Therefore, the running stability due to the swinging of the rear axle 10 can be further secured, and the slip caused by the locking of the rear axle 10 when the vehicle weight is applied to the rear wheel 11 can be reduced.

(B) Since the set value of the lateral G corresponding to the height of the center of gravity can be indirectly determined from the combination of the detected values of the load w and the height H, the height of the center of gravity is not actually calculated. I can do it. (C) A method of determining the set value of the horizontal G by dividing the load w and the lift H into two stages, and determining which of the combinations divided into two stages to which of the combinations by a comparison determination process. Therefore, it is not necessary to use a complicated calculation or map for determining the set value of the horizontal G from the detected values w and H, and it is possible to perform simple control.

(D) Since a limit switch is employed as the elevation sensor 23, no AD conversion circuit is required and control is simple. (E) Since the yaw rate change rate ΔY is employed in addition to the lateral G as the determination value of the swing control, the rear axle 10 can be locked earlier at the timing of the start of turning of the steering wheel 12, and once locked during the turning of the steering wheel 12. The problem that the rear axle 10 is temporarily unlocked can be prevented.

(F) The tire angle sensor 21 whose detection value is not easily affected by noise or the like due to vibration of the machine base or the like is adopted, and when calculating the ΔY value, the 1 / r value obtained from the detection value θ is calculated as a difference ( Since the differential (differential) process is employed, there is no need to worry about amplification of noise due to the differential (differential) processing, and a highly reliable estimated value ΔY can be obtained.

(G) Since the determination values ΔY and Gs are estimated by calculation from the tire angle θ and the vehicle speed V, it is not necessary to provide a detector such as an acceleration sensor for detecting the direct lateral G. In particular, if the tire angle sensor 21 and the vehicle speed sensor 22 are configured to share the one originally provided in the forklift 1 for another purpose, the cost of the apparatus can be reduced.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, the method of determining the set value of the horizontal G is different from that of the first embodiment. That is, by setting the set value of the lateral G so as to continuously change with respect to the height H, and using a sensor capable of detecting a continuous change in the height as a height sensor,
The set value of the lateral G is selected more finely and appropriately for the height H detected by the height sensor. It should be noted that since the method of determining the set value of the lateral G is different from that of the first embodiment, and the other controls are the same, the lateral G
Only the process of determining the set value of will be described.

As shown in FIG. 9, in this embodiment, a reel 41 connected to the lift bracket 4a and capable of winding the wire 40 is provided.
A reel-type lift sensor 42 that detects the lift H by detecting the winding amount of 0 as the rotation amount is used. The lift H of the fork 4 is continuously detected by the lift sensor 42. The detection value of the lift sensor 42 is input to the microcomputer 26 via an AD conversion circuit (not shown). In addition, as the height sensor,
For example, a sensor of a type that continuously detects the piston position of the lift cylinder 6 may be employed.

The two maps shown in FIGS. 10A and 10B are stored in the ROM 32. The two maps are used depending on whether the detected value w of the pressure sensor 24 is less than wo or greater than wo. Each map is set by continuously changing the set value of the lateral G with respect to the lift H, and is the severest maximum load in the load range used (see FIG. 10).
The map of FIG. 10A is created on the assumption that the load is wo, and the map of FIG. 10B is created on the assumption that the load is wmax).

According to this embodiment, the CPU 31 determines whether the detected value w of the pressure sensor 24 is less than wo or greater than wo, selects a map to be used, and inputs the map from the elevation sensor 42 using the selected map. The set value of the horizontal G is determined according to the lift H at that time. As described above, since the set value of the lateral G can be more finely determined according to the actual lift H, unnecessary lock of the rear axle 10 can be further reduced as compared with the configuration of the first embodiment.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to FIG. This embodiment is also an embodiment in which the method of determining the set value of the horizontal G is different.
That is, the value for selecting the set value of the lateral G is set to the load w so that the appropriate set value of the lateral G according to the load can be determined.
Is set to change continuously.

In the present embodiment, the same height sensor 23 and pressure sensor 24 as in the first embodiment are used as the height detector and the load detector. CPU 31 is a pressure sensor 2
4 and the lift sensor 23
And an on / off signal from the controller. The lift sensor 23 is turned on when the lift H is equal to or greater than ho. FIG. 11 (a),
The two maps shown in (b) are stored in the ROM 32. The two maps are selectively used depending on whether the height H is less than ho or greater than ho based on the on / off signal of the height sensor 23. Each map is set by continuously changing the set value of the horizontal G with respect to the load w, and the severest maximum height in the height range used (the map of FIG. 11A is the height ho). And the map in FIG.
) Is created assuming the case of).

According to this embodiment, the CPU 31 determines whether the lift H is less than ho or more than ho in accordance with the on / off signal of the lift sensor 23, selects a map to be used, and uses the selected map. Then, the set value of the lateral G is determined according to the current load w input from the pressure sensor 24. As described above, since the set value of the lateral G can be more finely determined according to the actual load w, unnecessary lock of the rear axle 10 can be further reduced as compared with the configuration of the first embodiment.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is also an embodiment in which the method of determining the set value of the horizontal G is different.
That is, the value for selecting the set value of the lateral G is set to the load w so that the appropriate set value of the lateral G according to the load can be determined.
And the height H are set to change continuously.

In the present embodiment, similar to the second embodiment,
The pressure sensor 24 and the reel type lift sensor 42 are used as a load detector and a lift detector. The CPU 31 inputs a load w continuously detected by the pressure sensor 24 and a lift H continuously detected by the lift sensor 42. In addition, as the lift sensor, for example, a sensor of a type that continuously detects the piston position of the lift cylinder 6 can be adopted.

The map shown in FIG. 12 is stored in the ROM 32. This map is obtained by continuously changing the set value of the lateral G with respect to each of the load w and the lift H, and sets an appropriate lateral G according to the center of gravity determined by the load w and the lift H. Is created so that you can select it. for that reason,
The free area is wider than that of the second and third embodiments.

According to this embodiment, the CPU 31 uses the map shown in FIG. 12 to calculate the horizontal G according to the height of the center of gravity from the load w and the lift H input as the detection values from the sensors 24 and 42. Determine the set value. In this way, a more appropriate set value of the lateral G for the swing control can be determined according to the accurate center of gravity determined by the load w and the lift H at that time. Therefore, unnecessary lock of the rear axle 10 can be further reduced as compared with the configurations of the second and third embodiments, and the unnecessary lock can be almost eliminated. Instead of using the three-dimensional map as shown in FIG. 12, a method of calculating the set value of the horizontal G from each of the detected values w and H may be adopted. In this case, a relatively complicated three-dimensional map is used. Since it is not necessary to store the map, it is possible to save the trouble of creating the map and to reduce the amount of data that needs to be stored in advance for the swing control.

The present invention is not limited to the above-described embodiment, but may be modified as appropriate without departing from the spirit of the invention, for example, as follows. (1) A method of calculating the height of the center of gravity hw using both the detected values H and w of the lift and the load and determining the set value of the lateral G according to the height of the center of gravity hw may be adopted. The method of determining the set value of the lateral G from the height of the center of gravity hw may be based on a map or by calculation. According to this method, in the fourth embodiment, FIG.
Can be replaced by a two-dimensional map representing the relationship between the height of the center of gravity hw and the set value of the lateral G, so that the process for determining the set value of the lateral G can be simplified.

(2) When the set value of the lateral G at the time of a heavy load and a high lift is set to a set value Go larger than “0” (0 <Go <
G1), the set value of the lateral G at other times is set to a constant value (for example, G1), and the set value of the lateral G is set to two stages of Go and G1 according to the load and the lift (that is, the height of the center of gravity). The configuration may be as follows. According to this configuration, the rear axle 10 is not locked when the Gs value is less than the set value Go even when the load is heavy and the lift is high, so that the lock of the rear axle 10 more than necessary can be reduced.

(3) In the first and second embodiments, the load detector is replaced with a sensor such as the pressure sensor 24 capable of continuously detecting a load, and a switch-type sensor that turns on with a predetermined load (switch-type detection) Container). With a switch type sensor, an AD conversion circuit is not required, and the CPU
31 can be simplified.

(4) In the first embodiment, the present invention is not limited to the method of setting the lift H and the load w in two steps. At least one may be divided into three or more stages. Lift H 3
In the case of dividing into stages or more, a height sensor capable of continuously detecting the height may be used, or a plurality of switch type detectors such as limit switches are combined so as to be able to detect the height in each stage. A lift sensor with a configuration may be used. When the load w is divided into three or more stages, a pressure sensor capable of continuously detecting the load may be used, or a configuration in which a plurality of switch-type detectors having different detected loads may be combined. Of course, by adopting these configurations, in the second and third embodiments, one of the load and the lift that is not continuously detected may be set in three or more steps of discontinuity.

(5) The yaw rate change rate ΔY in addition to the lateral G may be determined based on the load and the lift, and the set value yo is determined according to the height of the center of gravity. That is, the set value yo is set by continuously or discontinuously changing the height of the center of gravity in advance so that the set value of the yaw rate change rate ΔY selected as the height of the center of gravity increases tends to become substantially small. Keep it. According to this configuration, it is not necessary to set the set value yo assuming that the center of gravity of the vehicle is high, and therefore, the yaw rate change rate ΔY when the height of the center of gravity of the vehicle is relatively low.
Unnecessary locking of the rear axle 10 can be reduced.
Of course, instead of the yaw rate change rate ΔY, the lateral G change rate Δ
The same control may be performed on the lateral G change rate ΔG by adopting G (= V · ΔY).

(6) The method of detecting the horizontal G is not limited to the above embodiment. For example, attach a gyroscope to the car body,
Using the detected value ω of the gyroscope and the vehicle speed value V of the vehicle speed sensor 22, the lateral G; Gs = V · ω, the yaw rate change rate Δ
A configuration for calculating Y = Δω / ΔT may be used. As the gyroscope, an appropriate type such as a piezoelectric gyroscope, a gas rate gyroscope, or an optical gyroscope can be used. Since the gyroscope is also a detector which is hardly affected by vibration of the machine base or the like, a highly reliable ΔY can be obtained. In addition, an acceleration sensor is attached to the vehicle,
May be detected. Further, instead of the tire angle sensor 21, a handle angle sensor for detecting the rotation angle of the handle 12 is used, the reciprocal value 1 / r of the turning radius is obtained from the handle angle θH, and the respective judgment values Gs, ΔY are calculated. Is also good. Further, a detector that detects the position of a piston of a steering cylinder constituting the power steering device may be employed as the tire angle sensor.

(7) 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 of the axle is small, or the axle may swing in a small range in the regulated state. It is sufficient if the swing range can be kept small when regulating the axle.

(8) The present invention may be applied to a battery type forklift. Further, the present invention may be applied to industrial vehicles other than forklifts. The technical ideas (inventions) grasped from the above embodiments and not described in the claims are listed below together with their effects.

(A) In the invention according to any one of claims 1 to 9, the vehicle includes a steering angle detector for detecting a steering angle of a steering wheel, and a vehicle speed detector for detecting a vehicle speed. The lateral G detecting means includes lateral G calculating means for calculating the lateral G using both the detected values of the steering angle and the vehicle speed. According to this configuration, since the lateral G is calculated by calculation using both the detected values of the steering angle of the steered wheels detected by the steering angle detector and the vehicle speed detected by the vehicle speed detector,
Even without using an acceleration sensor that can directly detect the lateral G
Can be obtained. In each of the above embodiments, the rear wheel 11 is a steered wheel, the tire angle sensor 21 is a steering angle detector, the vehicle speed sensor 22 is a vehicle speed detector, and the CPU 31 is a lateral G.
Each of the calculation means is configured.

(B) In the invention as set forth in claim 2, the control means sets the yaw rate change rate from a set value for the rate of change of the yaw rate, which is set in advance in a discontinuous or continuous manner relative to the height of the center of gravity. Select a set value according to the height of the center of gravity of the vehicle,
When the rate of change of the yaw rate is equal to or more than the set value, the axle restricting mechanism is operated to restrict the swing of the axle. According to this configuration, even when the axle restricting mechanism is operated based on the detected yaw rate change rate in addition to the lateral G, the set value for the yaw rate change rate is selected from the set values according to the height of the center of gravity. In addition, unnecessary regulation of the axle can be reduced in the regulation control of the axle swing based on the detected yaw rate change rate.

[0091]

As described above, according to the first aspect of the present invention, the set value of the lateral G used for determining whether or not to restrict the axle swing is set in advance to the height of the center of gravity of the vehicle. Depending on the height of the center of gravity of the vehicle, a more appropriate value of the lateral G is selected from the set values. Unnecessary regulation of the swing can be reduced.

According to the second aspect of the present invention, even when the rate of change of the yaw rate of the vehicle exceeds a set value, the swing of the axle is regulated. Of the axle can be prevented from being released during the turning of the steering wheel.

According to the third aspect of the present invention, the set value of the lateral G is selected from the preset set values based on both the detected values of the lift and the load. The set value of the lateral G according to the height of the center of gravity of the vehicle can be obtained indirectly from the detected values of the load and the load.

According to the fourth aspect of the present invention, since the plurality of preset values are discontinuous with respect to the lift and the load, each detected value of the lift and the load is determined by comparison with the comparison value. The set value of the horizontal G can be determined by a simple process.

According to the fifth aspect of the present invention, since the detector provided in at least one of the height detector and the load detector is a switch type detector, an AD conversion circuit or the like is unnecessary, and the The configuration can be simplified and the control can be simplified.

According to the sixth aspect of the invention, at least one of the height detector and the load detector is a detector capable of detecting a continuous change, and a preset value is set to the continuous change of the detector. Since the detected value is continuously changed, a more appropriate set value of the lateral G according to the height of the center of gravity is finely determined, and unnecessary swing regulation of the axle can be further reduced.

According to the seventh aspect of the present invention, the preset value is changed continuously with respect to the height continuously detected by the height detector. It is determined more appropriately, and unnecessary swing regulation of the axle can be further reduced.

According to the eighth aspect of the invention, since the preset set value is continuously changed with respect to the load continuously detected by the load detector, the set value of the lateral G is more appropriate. And the unnecessary swing regulation of the axle can be further reduced.

According to the ninth aspect of the present invention, since the preset value is continuously changed with respect to the lift and the load, the most appropriate lateral G according to the lift and the load is changed. Can be determined, and unnecessary swing regulation of the axle can be further reduced.

[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 yaw rate change rate during turning.

FIG. 6 is a map diagram for obtaining a set value of a horizontal G;

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

FIG. 8 is also a flowchart.

FIG. 9 is a partial side view of a forklift according to the second embodiment.

FIG. 10 is a map diagram for obtaining a set value of a horizontal G;

FIG. 11 is a map diagram for obtaining a set value of a horizontal G in the third embodiment.

FIG. 12 is a map diagram for obtaining a set value of a horizontal G in the fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Forklift as an industrial vehicle, 1a ... Body frame as a vehicle body, 4 ... Fork as loading equipment, 1
0 ... rear axle as axle, 11 ... rear wheel as steered wheel, 13 ... hydraulic damper constituting axle regulation mechanism, 1
4 ... an electromagnetic switching valve which constitutes an axle regulating mechanism and also serves as a switching valve; 21 ... a tire angle sensor which constitutes lateral G detecting means and yaw rate change detecting means; 22 ... a vehicle speed which constitutes lateral G detecting means and yaw rate change detecting means. Sensor, 23
... A lift sensor as a height detector and a switch type detector which constitutes a center-of-gravity height detector and 24. A pressure sensor which constitutes a center-of-gravity height detector and as a load detector, 25. 31 ... Side G
CP constituting detecting means and yaw rate change detecting means
U, 42: Height sensor as a height detector that constitutes the center of gravity height detecting means, Gs: lateral G, ΔY: yaw rate change rate.

Claims (9)

[Claims] An axle supported to be able to swing up and down with respect to a vehicle body, an axle regulating mechanism for regulating swing of the axle, and a lateral G detecting means for detecting a lateral G of the vehicle; A center-of-gravity height detecting means for directly or indirectly detecting the center-of-gravity height of the vehicle; and A set value corresponding to the height of the center of gravity of the vehicle detected by the above is selected, and when the lateral G detected by the lateral G detecting means is equal to or greater than the set value, the axle restricting mechanism is controlled to regulate the axle swing. A vehicle body swing control device for an industrial vehicle, comprising: a control unit for operating the vehicle body. 2. The vehicle according to claim 1, further comprising: a yaw rate change detection unit configured to detect a change rate of the yaw rate of the vehicle with respect to time, wherein the control unit sets the yaw rate change rate detected by the yaw rate change detection unit to a predetermined value or more. 2. The vehicle body swing control device for an industrial vehicle according to claim 1, wherein the vehicle axle regulation mechanism is set so as to operate the axle regulation mechanism even when the axle swings. 3. The height-of-gravity detecting means includes a height detector for detecting a height of a loading device provided for loading a load on a vehicle, and a load detecting device for detecting a load of the load on the loading device. The control means is set to determine the set value according to the height of the center of gravity of the vehicle based on both the detected values of the lift and the load from the set values set in advance. The vehicle body swing control device for an industrial vehicle according to claim 1 or 2, wherein 4. The vehicle body swing control device for an industrial vehicle according to claim 3, wherein a plurality of the preset values are set discontinuously with respect to the lift and the load. 5. The control device according to claim 4, wherein at least one of the height detector and the load detector is a switch-type detector. 6. At least one of said height detector and said load detector is a detector capable of detecting a continuous change, and said detector is set in advance with respect to a detection value detected by said detector. 4. The vehicle body swing control device for an industrial vehicle according to claim 3, wherein the set value is set to be continuously changed. 7. The height detector is a detector capable of detecting a continuous change in the height, and the preset value is continuously changed with respect to the height. 7. The vehicle body swing control device for an industrial vehicle according to 6. 8. The load detector according to claim 6, wherein the load detector is a detector capable of detecting a continuous change in load, and the preset value is set to be continuously changed with respect to the load. Body swing control device for industrial vehicles. 9. The lift detector and the load detector are both detectors capable of detecting a continuous change in the lift and the load, respectively, and the set value set in advance is both the lift and the load. The vehicle body swing control device for an industrial vehicle according to claim 6, wherein the vehicle body swing control device is set so as to continuously change with respect to the detected value.