JP2006160406A - Cargo-handling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo-handling vehicle, including wheels respectively mounted on a pair of straddle arms to move up and down through a suspension device, thereby restraining vibration of the vehicle and preventing useless rocking and inclination of the vehicle. <P>SOLUTION: This cargo-handling vehicle includes: regulating means 27L, 27R for regulating the operation of the suspension device to restrain vertical movement of the wheels; a height detecting means 4A for detecting the height of a cargo-handling tool; and a control means 14 for controlling the regulating means 27L, 27R according to the height. The control means 14 regulates the operation of both suspension devices by the regulating means 27L, 27R when the height is above a predetermined one, and releases the regulation of the regulating means 27L, 27R when it is not above the predetermined height. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cargo handling vehicle in which wheels are suspended by a suspension device.

  Some cargo handling vehicles used for cargo handling work include a straddle arm on one side of a vehicle body. For example, in a reach forklift, a pair of left and right straddle arms protrudes forward from the vehicle body, and a mast device equipped with a fork moves forward and backward along these straddle arms. It is supported freely. Further, for example, in an order picking truck, a pair of left and right straddle arms protrudes rearward from the vehicle body, and wheels are rotatably supported by these straddle arms, and are moved up and down to a mast device standing on the straddle arm. A cab that also serves as a workbench is provided.

  As a structure for supporting the wheel on the straddle arm, conventionally, a structure in which the wheel is fitted to the axle fixed to the straddle arm via a bearing has been adopted. When running, the car body vibrates, and there is a problem that the ride comfort is very bad and the cargo collapses easily. Thus, for example, as shown in Patent Document 1, a technique has been developed in which a wheel is provided so as to be movable up and down by a suspension device using a spring.

  Now, if the wheels are provided so that they can move up and down, vibrations can be suppressed even when traveling over unevenness on the road surface, so ride comfort can be improved and load collapse can be prevented.However, depending on the situation, if the wheels move up and down, the posture of the vehicle May become unstable. For example, in a reach-type forklift, if the rear wheel is provided on the vehicle body so that it can move up and down, sudden braking during a sharp turn may cause the vehicle body to sink to the rear wheel side due to inertia and cause the front wheel to float. . Therefore, for example, as shown in Patent Document 2, the vertical movement of the rear wheel is prevented to prevent the front wheel from lifting and the stability of the vehicle is maintained. Further, as shown in Patent Document 3, the speed of the suspension mechanism is limited or restricted during reverse acceleration, and as shown in Patent Document 4, the suspension mechanism is operated when a cargo handling device (mast device, fork) is operated. Attempts have also been made to limit or regulate speed.

JP 2004-277068 A JP 2003-81597 A JP 2002-29236 A JP 2001-328799 A

  Even in a cargo handling vehicle in which wheels are provided on a straddle arm via a suspension device so that the wheels can move up and down as shown in Patent Document 1, depending on the situation, the vehicle body becomes unstable due to the fact that the wheels can move up and down. It is possible to do. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to prevent unnecessary vehicle shake and tilt while suppressing the vibration of the vehicle by allowing the wheels to move up and down in such a cargo handling vehicle.

  In order to achieve the above object, the present invention is provided with a pair of straddle arms projecting from one side of the vehicle body to one side. In a cargo handling vehicle in which wheels are supported by a straddle arm via a suspension device so as to be able to move up and down, regulation means for regulating the operation of the suspension device so that the vertical movement of the wheels is suppressed, and the lifting height of the cargo handling equipment And a control means for controlling the restricting means based on the lift. When the lift is equal to or higher than a predetermined height, the control means uses the restricting means to When the operation of both suspension devices is restricted and the lifting height is not equal to or higher than the predetermined height, the restriction by the restriction means is released and the suspension device It has a configuration which is characterized by allowing dynamic.

  According to this, when the lifting height of the cargo handling equipment is higher than the predetermined height, the operation of the suspension device is restricted and the vertical movement of the wheel is suppressed. Even if the load fluctuates due to movement or the like, the wheel does not move up and down with respect to the straddle arm and the vehicle body, so that the posture of the vehicle can be kept stable. On the other hand, since the operation of the suspension device is not restricted when the lifting height of the cargo handling equipment is low, the wheels can move up and down according to the unevenness of the road surface, and the vibration of the vehicle can be suppressed.

  In the present invention, the vehicle includes a traveling speed detecting unit that detects a traveling speed of the vehicle and a steering angle detecting unit that detects a steering angle of a steering wheel included in the vehicle, and the control unit includes the lift height, The control means controls the regulating means based on the running speed and the rudder angle. The control means has the running speed equal to or higher than a predetermined speed when the lift is not higher than the predetermined height. When the rudder angle is equal to or greater than a predetermined angle from the straight traveling state, the operation of the suspension device that supports the outer ring is restricted by the restriction means, and the operation of the suspension device that supports the inner ring by releasing the restriction by the restriction means It can be set as the structure characterized by accepting.

  In this way, even when the lifting height of the cargo handling equipment is lower than the predetermined height, if the traveling speed is faster than the predetermined speed and the rudder angle is larger than the predetermined angle, the suspension device that supports the outer wheel Since the operation is restricted and the vertical movement of the outer ring is suppressed, it is possible to suppress the vehicle that is turning while being tilted outward. Further, since the restriction on the suspension device that supports the inner ring is released and the vertical movement of the inner ring is permitted, the ground contact state of the inner ring can be maintained, and the posture of the vehicle can be stably maintained.

  In the present invention, the cargo handling device includes a mast device supported by the straddle arm, and a work table on which an operator rides and is supported by the mast device so as to be movable up and down integrally with the cargo handling tool. If the work table extends from the mast device in the projecting direction of the straddle arm, the operation of the suspension device is appropriately restricted by the restricting means, and the vertical movement of the wheel is suppressed. By doing so, it is possible to keep the posture of the vehicle stable and prevent the mast device and the workbench from shaking or tilting so that the worker on the workbench does not feel anxiety.

  Further, in the present invention, to suppress the vertical movement of the wheel means that the vertical movement is completely disabled, and that the range in which the vertical movement is possible is limited, or the speed of the vertical movement is limited to be small. Including meaning, restricting the operation of the suspension device includes not only completely prohibiting (stopping) the operation, but also restricting the operable range narrowly or limiting the operating speed to be small. Meaning.

According to the present invention, since the operation of the suspension device is restricted during the work at a high place where the lifting height of the cargo handling equipment is higher than the predetermined height, and the vertical movement of the wheel is suppressed, the vehicle can be operated even if the load fluctuates. Can be kept stable. On the other hand, since the operation of the suspension device is not restricted when the lift height is low, the vehicle vibration can be suppressed by the vertical movement of the wheels.
Further, in the present invention, even when the lift height is low, the operation of the suspension device that supports the outer ring is restricted when the traveling speed is equal to or higher than the predetermined speed and the rudder angle is equal to or higher than the predetermined angle from the straight traveling state. If the operation of the supporting suspension device is allowed, the posture of the vehicle during turning can be stably maintained.

  Hereinafter, an embodiment in which the present invention is applied to an order picking truck which is a kind of cargo handling vehicle will be described with reference to the drawings.

  As shown in FIG. 1, the order picking truck according to this embodiment has a pair of straddle arms 2 projecting left and right from the rear portion of the vehicle body 1 toward the rear, and a base end portion of the straddle arm 2 ( A mast device 3 is erected on the front end portion. A cab 4 also serving as a work table is supported by the mast device 3 so as to be able to move up and down. The cab 4 extends rearward from the mast device 3 and is disposed above the straddle arm 2. A pair of left and right forks 5 project from the floor of the cab 4 toward the rear, and the cab 4 and the forks 5 move up and down integrally along the mast device 3. Further, the mast device 3 is provided with a lift height sensor 4A for detecting a lift height h from the ground of the driver's cab 4 and the fork 5 and the lift height h detected by the lift height sensor 4A is a control described later. To the device 14.

  Now, as shown in FIG. 1, the cab 4 includes a floor portion on which an operator gets on, a front wall portion supported by the mast device 3, and a ceiling portion that covers the floor portion from above. On the rear side (operator side), a steering handle 6, an accelerator lever 7, an ascending operation button 8, a descending operation button 9, and the like for driving the order picking truck are provided. A front wheel 10 is provided at the front portion of the vehicle body 1, and a rear wheel 20 is provided at the front end portion (rear end portion) of each straddle arm 2, and the front wheel 10 is rotated around the vertical axis according to the operation of the steering handle 6. The vehicle is steered by turning it to the right, and travels by rotating the front wheel 10 about the horizontal axis in accordance with the operation of the accelerator lever 7. Further, the cab 4 and the fork 5 are moved up and down by extending and retracting the mast device 3 in the vertical direction according to the operation of the ascending operation button 8 and the descending operation button 9.

  As shown in FIG. 2, a drive device 11 is provided at the center in the left-right direction of the front portion of the vehicle body 1 so as to be able to turn around a vertical axis, and the drive device 11 serves as a driving wheel and a steering wheel. 10 is supported rotatably around the horizontal axis. A drive motor 12 is connected to the drive device 11, and driving torque from the drive motor 12 is transmitted to the front wheel 10 via the drive device 11, and the front wheel 10 is rotated. The traveling motor 12 is driven in the forward rotation direction or the reverse rotation direction in accordance with the operation of the accelerator lever 7. For example, when the traveling motor 12 is driven in the forward rotation direction with the front wheel 10 in the straight traveling state, the forward traveling is performed straight. When the vehicle is driven in the reverse direction, the vehicle travels straight backward. The drive device 11 is provided with a steering motor (not shown), and the drive device 11 is turned to the left and right integrally with the front wheels 10 by the steering motor driven in accordance with the operation of the steering handle 6 and steered. Is made. Further, a hydraulic device 13 for extending and retracting the mast device 3 is provided on the right side of the drive device 11 at the front of the vehicle body 1, and a control device 14 is provided on the left side of the drive device 11. The drive device 11 is provided with a steering angle sensor 11A that detects a steering angle s that is a turning angle around the vertical axis, and the traveling motor 12 is provided with a speed sensor 12A that detects the rotational speed and the rotational direction. Therefore, the detection results by both sensors are transmitted to the control device 14.

  The front wheel 10 and the drive device 11 can turn 90 degrees left and right around the straight traveling state. As shown in FIG. 3, the rudder angle sensor 11A steers the front wheel 10 with the straight traveling state at 0 degree. The angle s is detected. That is, the rudder angle sensor 11A detects the rudder angle s when the front wheel 10 turns in the clockwise direction in the plan view from the straight traveling state as a positive value, and determines the rudder angle s in the case of the left turn in the plan view from the straight traveling state. Detect with negative value.

  As shown in FIG. 4, the straddle arm 2 has a hollow shape, and the rear wheel 20 is supported via suspension devices 21 </ b> L and 21 </ b> R provided in each straddle arm 2. A suspension device 21L is provided in the left straddle arm 2, and a suspension device 21R is provided in the right straddle arm 2, and one rear wheel 20 is supported by each suspension device. The suspension device 21L (R) includes a shaft 22L (R) fixed to the rear portion of the straddle arm 2 and a suspension arm 23L (R) supported by the shaft 22L (R) so as to be swingable up and down. The rear wheel 20 is rotatably supported at the rear part of the arm 23L (R). The suspension device 21L (R) includes a shaft 24L (R) fixed to the front portion of the straddle arm 2, a front portion supported by the shaft 24L (R), and a rear portion coupled to the suspension arm 23L (R). Suspension cylinder 25L (R). The suspension cylinder 25L (R) is arranged so as to expand and contract in the front-rear direction, that is, the projecting direction of the straddle arm 2, and a coil spring 26L (R) is interposed in the suspension cylinder 25L (R) and electromagnetic A valve 27L (R) is attached.

  Each of the suspension cylinders 25L and 25R includes a front and rear oil chamber and a hydraulic circuit that connects both the oil chambers. The suspension cylinders 25L and 25R are arranged on the front side (the shafts 24L and 24R side) from the oil chamber on the rear side (suspension arms 23L and 23R side). It is extended by the movement of the hydraulic oil to the oil chamber, and shortened by the movement of the hydraulic oil from the front oil chamber to the rear oil chamber. When the suspension cylinders 25L and 25R are extended, the suspension arms 23L and 23R are swung downward, thereby moving the rear wheel 20 downward. Further, when the suspension cylinders 25L and 25R are shortened, the suspension arms 23L and 23R are swung upward, thereby moving the rear wheel 20 upward. As shown in FIG. 5, the electromagnetic valves 27L and 27R are provided in the middle of the hydraulic circuit connecting the two oil chambers in the suspension cylinders 25L and 25R, respectively. When is stopped, the hydraulic circuit is switched off by a built-in spring. The coil springs 26L and 26R are provided to urge the suspension cylinders 25L and 25R, respectively, with a predetermined urging force in the extending direction.

  As shown in FIG. 5, the detection results by the elevation sensor 4A, the steering angle sensor 11A, and the speed sensor 12A are transmitted to the control device 14, and the control device 14 controls the electromagnetic valves 27L and 27R based on them. Then, when the electromagnetic valve 27L (R) is energized by the control device 14, the hydraulic circuit connecting both the oil chambers is connected to allow the suspension cylinder 25L (R) to extend and contract (hereinafter referred to as an unlocked state). It becomes. On the other hand, when the energization of the electromagnetic valve 27L (R) is stopped, the hydraulic circuit connecting the two oil chambers is cut off, and the suspension cylinder 25L (R) is prohibited from extending and contracting (hereinafter referred to as a locked state). .

  As shown in FIG. 6, the control device 14 determines whether or not the lift height h detected by the lift sensor 4A is equal to or higher than a predetermined height H (S1). The energization of the electromagnetic valves 27L and 27R is stopped, and the suspension cylinders 25L and 25R are locked (S2). If the lift height h is not higher than the height H, the traveling speed v of this order picking truck is obtained based on the rotational speed of the traveling motor 12 detected by the speed sensor 12A, and the traveling speed v is equal to or higher than the predetermined speed V. It is determined whether or not there is (S3). If the traveling speed v is equal to or higher than the speed V, the control device 14 subsequently obtains the magnitude (absolute value) | s | of the rudder angle s detected by the rudder angle sensor 11A, and this is a predetermined angle Sa (> 0). ) It is determined whether or not (S4). If the magnitude | s | of the steering angle s is equal to or greater than the angle Sa, it is further determined whether or not it is equal to or greater than a predetermined angle Sb (> Sa) (S5). If the magnitude | s | It is determined whether or not the value is greater than or equal to value B (S6). That is, the deceleration b which is the magnitude of the decrease rate of the traveling speed v is obtained and compared with the reference value B (> 0) set in the control device 14 in advance, whether or not it is equal to or more than the reference value B. Determine. If the deceleration b is not equal to or greater than the reference value B, the control device 14 stops energization of the electromagnetic valves 27L and 27R and puts the suspension cylinders 25L and 25R into a locked state (S2).

  In S5, if the magnitude | s | of the steering angle s is not equal to or greater than the angle Sb, that is, Sa ≦ | s | <Sb, the control device 14 is detected by the steering angle sensor 11A as shown in FIG. It is determined whether or not the steering angle s is a positive value (S7). Here, if the steering angle s is a negative value, the control device 14 energizes the electromagnetic valve 27L to bring the suspension cylinder 25L into an unlocked state, and stops energization of the electromagnetic valve 27R to activate the suspension cylinder 25R. The locked state is set (S8). If the steering angle s is a positive value, the control device 14 stops energization of the electromagnetic valve 27L to place the suspension cylinder 25L in the locked state, and energizes the electromagnetic valve 27R to bring the suspension cylinder 25R into the unlocked state. (S9).

  In S6, if the deceleration b is greater than or equal to the reference value B, that is, if the vehicle is rapidly decelerating, the control device 14 rotates the travel motor 12 detected by the speed sensor 12A as shown in FIG. It is determined whether or not the order picking truck is traveling forward based on the direction (S10). If the traveling motor 12 is rotating in the forward rotation direction, the control device 14 determines that the vehicle is traveling forward, and determines whether the steering angle s is a positive value (S7). Here, if the steering angle s is a negative value, the control device 14 sets the suspension cylinder 25L to the unlocked state and the suspension cylinder 25R to the locked state (S8), and if the steering angle s is a positive value. Then, the suspension cylinder 25L is locked and the suspension cylinder 25R is unlocked (S9). On the other hand, if the traveling motor 12 rotates in the reverse direction, the control device 14 determines that the vehicle travels backward and determines whether the steering angle s is a positive value (S11). Here, if the steering angle s is a positive value, the control device 14 sets the suspension cylinder 25L to the unlocked state and the suspension cylinder 25R to the locked state (S8), and if the steering angle s is a negative value. Then, the suspension cylinder 25L is locked and the suspension cylinder 25R is unlocked (S9).

  As shown in FIG. 6, if the traveling speed v is not equal to or higher than the speed V in S3 or the magnitude | s | of the rudder angle s is not equal to or greater than the angle Sa in S4, the control device 14 controls the electromagnetic valves 27L and 27R. Is energized to bring the suspension cylinders 25L, 25R into the unlocked state (S12).

  According to such an embodiment, when the lift height h of the cab 4 and the fork 5 is higher than the height H, the suspension cylinders 25L and 25R are locked and the suspension arms 23L and 23R are prohibited from swinging. Therefore, the vertical movement of both rear wheels 20 is stopped. Thereby, even if the load fluctuates due to loading / unloading of the load at a high place, the posture of the order picking truck can be stably maintained. Further, even when the lift height h of the cab 4 and the fork 5 is lower than the height H, the turning speed v is higher than the speed V, and the turning angle s | s | is larger than the angle Sb. When traveling, since the suspension cylinders 25L and 25R are locked, unnecessary vertical movement of the rear wheel 20 accompanying turning traveling can be stopped and the posture can be stabilized.

  When the lift height h of the cab 4 and the fork 5 is lower than the height H and the traveling speed v is faster than the speed V, the magnitude | s | of the rudder angle s is larger than the angle Sa and larger than the angle Sb. If it is small, the vertical movement of the rear wheel 20 as the outer ring is stopped, and the vertical movement of the rear wheel 20 as the inner ring is allowed. As a result, the vehicle body 1 can be prevented from sinking and tilting outward due to the centrifugal force acting during turning, and the grounding state of both rear wheels 20 can be maintained to stabilize the posture of the order picking truck. Can be kept. Further, if the traveling speed v is faster than the speed V and the magnitude of the rudder angle s | s | is larger than the angle Sb, braking is applied, and if the deceleration b at this time is larger than the reference value B, the process proceeds. The vertical movement of the rear wheel 20 on the direction side is stopped, and the vertical movement of the rear wheel 20 on the side opposite to the traveling direction is allowed. Thereby, even if an inertial force is applied due to sudden braking, the grounding state of both rear wheels 20 can be maintained and the posture can be stably maintained.

  When the lift height h of the cab 4 and the fork 5 is lower than the height H, if the traveling speed v is slower than the speed V or the magnitude | s | of the rudder angle s is smaller than the angle Sa, the suspension The cylinders 25L and 25R are unlocked, and the suspension arms 23L and 23R can swing. Therefore, each rear wheel 20 can move up and down according to the unevenness of the road surface, etc., and vibrations of the vehicle body 1 and thus the cab 4 and the fork 5 can be suppressed.

It is a perspective view of the embodiment of the present invention. It is a perspective view of the embodiment of the present invention. It is a schematic diagram of an embodiment of the present invention. It is a perspective view of the embodiment of the present invention. It is a functional block diagram of an embodiment of the present invention. It is a control flow figure of an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Straddle arm 4 Driver's cab 4A Lifting height sensor 10 Front wheel 11 Drive apparatus 11A Steering angle sensor 12 Running motor 12A Speed sensor 14 Control apparatus 20 Rear wheel 21L, 21R Suspension apparatus 25L, 25R Suspension cylinder 27L, 27R Electromagnetic valve

Claims (3)

A pair of straddle arms project from the vehicle body to one side, and the straddle arm is provided with a cargo handling device provided with a lifting tool that can be moved up and down, and wheels are moved vertically to each straddle arm via a suspension device. In a cargo handling vehicle that is supported,
Restricting means for restricting the operation of the suspension device so that vertical movement of the wheel is suppressed, lifting height detecting means for detecting the lifting height of the cargo handling equipment, and control for controlling the restricting means based on the lifting height Means and
The control means restricts the operation of the suspension devices by the restricting means when the lift is equal to or higher than a predetermined height, and controls the operation by the restricting means when the lift is not equal to or higher than the predetermined height. A cargo handling vehicle characterized in that the operation of the suspension device is permitted by releasing the regulation. A travel speed detecting means for detecting a travel speed of the vehicle; and a steering angle detecting means for detecting a steering angle of a steered wheel provided in the vehicle. The control means includes the lift, the travel speed, and the rudder. The control means is controlled based on the angle,
When the lift is not equal to or higher than the predetermined height, and the traveling speed is equal to or higher than the predetermined speed and the steering angle is equal to or higher than the predetermined angle from the straight traveling state, the control means 2. The cargo handling vehicle according to claim 1, wherein the operation of the suspension device to be supported is restricted, and the operation of the suspension device that supports the inner ring is permitted by releasing the restriction by the restriction means.   The cargo handling apparatus includes a mast device supported by the straddle arm, and a work table on which an operator gets on, which is supported by the mast device so as to be movable up and down, and moves up and down integrally with the cargo handling equipment. The cargo handling vehicle according to claim 1 or 2, wherein the platform extends from the mast device in a projecting direction of the straddle arm.

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