JP2631327B2 - Road Wheel Steering Device for Reach Type Forklift - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reach type forklift capable of steering a road wheel supported at the tip of a straddle arm. The present invention relates to a steering device capable of realizing steering of a road wheel with extremely small dimensions without increasing the size of the steering wheel. 2. Description of the Related Art Conventionally, a forklift k shown in FIGS. 6 and 7 has been proposed. This forklift k
When the traveling direction is assumed to be A, the caster wheels m and p are pivoted and fixed along the traveling direction, and the cylinders s1 and s2 are hydraulically controlled so that the caster wheels n can be pivoted. Ackerman steering can be performed by steering the wheel l. When the traveling direction is set to B, the caster wheels n and p are pivoted and fixed along the traveling direction, and the cylinders s1 and s2 are hydraulically controlled so that the caster wheel m can be pivoted. Ackerman steering can be performed in the same manner as described above by steering the direction and drive wheel l. [0004] However, since a forklift is usually required to perform a cargo handling operation in a narrow warehouse passage, as described above, a cylinder is provided in the straddle arms r, r. s1, s2 and the cylinder s
1, s2 and links i, j for steering each caster wheel
Is arranged, the width of the straddle arms r, r is large,
As a result, the width of the vehicle body is enlarged. Therefore, there is a problem that the minimum passage width must be increased, and the storage space for the load is reduced. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a road wheel for a reach type forklift in which the width of a straddle arm that supports the left and right road wheels so as to be steerable can be made extremely small. To provide a steering device. According to the present invention, the center of the left and right straddle arms is located near the tip of each of the left and right straddle arms and at the outer position in the vehicle body width direction. Each bracket is rotatably supported, and the hanging portions of the inverted L-shaped cross-section bracket fixed to the steering shaft are respectively arranged toward the outside of the vehicle body, and the hanging portions are parallel to the horizontal axis in the vehicle width direction. A shaft is fixed, the load shaft is rotatably supported on the bearing shaft by a predetermined distance from the center of the steering shaft in the width direction of the load wheel toward the center of the vehicle body and a width of the straddle arm. A gear that is cut out in a fan shape so as not to exceed, a gear whose arc side faces the center of the vehicle body is fixed to the bracket, and a drive gear that meshes with the gear that is cut out in the fan shape is a drive gear. Than notched gear shape in from the vehicle body center side, it is obtained by the structure that houses arranged on the left and right straddle arms within each. FIG. 1 to FIG. 4 show an embodiment of the present invention.
It will be described based on. The forklift 1 includes a main body 2 and
Left and right straddle arms 10 projecting from the main body 2,
The main body 2 is provided with a drive wheel 11 that can be steered by a steering wheel 6 while the road wheels 12L and 12R are steerably supported on each of the wheels 10. A mast 3 is provided between the straddle arms 10 and 10 to be able to slide back and forth and to be able to move up and down by a lift cylinder 5 to lock cargo handling devices 4 and 4 such as forks or various attachments. Reference numeral 7 denotes a cargo handling lever for operating the cargo handling implement 4, reference numeral 8 denotes a traveling operation lever for giving an instruction to accelerate the drive wheel, and reference numeral 9 denotes a battery. Next, the steering mechanism of the road wheel will be described in detail.
The bearing 14 is rotatably supported via a bearing.
The hanging portion 1 of the bracket 13 having a substantially "L" shape when viewed from the front.
3a. Also, the outer surface of the hanging part 13a
The straddle arm 10 is configured to substantially coincide with the outer surface. Further, on the upper surface of the bracket 13, a steering shaft 16 protruding upward is provided with a tapered roller bearing 21,
At 21, it is rotatably supported. Tapered roller bearing 2
1, 21 can support the moment load generated on the steering shaft 16 in combination with the rear surface. The center of the steering shaft 16 is located at an outer position in the vehicle width direction. At the inner end of the bracket 13, a gear 20 cut in a fan shape so as not to exceed the width of the straddle arm 10 is fixed by bolts 23, and a driving gear 19 meshed with the fan-shaped gear 20. Are fitted in the drive shaft 17. By forming the gear in a sector shape in this way, a gear that can obtain a sufficient reduction ratio can be used,
The straddle arm 10 can be prevented from expanding in the width direction.
The fan-shaped gear 20 has a circular arc portion of approximately 230 degrees, and can turn left and right by approximately 115 degrees. The upper surface of the bracket 13 does not come into contact with the straddle arm 10, and all the loads acting on the steering shaft 16 are carried by the tapered roller bearings 21, 21. The drive shaft 17 is provided in parallel with the steering shaft 16, is rotatably supported by a boss 22, and has a timing pulley 18 fixed to the upper end thereof.
A steering motor 34L is fixed in the straddle arm 10, and its pinion 33 is turned around a rotation shaft 29 via a one-stage reduction gear 31, an idle gear 32 formed coaxially therewith and a two-stage reduction gear 30. Can be moved. Further, a timing pulley 25 is fixed to the upper end of the rotary shaft 29, and the torque of the steering motor 34L is transmitted to the timing pulley 18 of the drive shaft 17 via a timing belt 35, so that the load wheel 12L is You can steer. In addition, 2 shown in FIGS.
Reference numeral 8 denotes an encoder, which is configured to detect a steering angle of the road wheel 12L by engaging a gear 27 provided at a tip of a detection shaft with a gear 26 fixed to the rotation shaft 29. The steering motor 34L described above,
The components such as the timing pulleys 18 and 25 and the steering shaft 16 are housed and arranged in the straddle arm 10 and have the same configuration for the other road wheel. Symmetrically around the center. Therefore, as shown in FIG. 8, when the steering motor 34L is driven to rotate the timing belt 35 as shown in FIG. 8, the torque is transmitted from the drive gear 19 to the sector gear 20 to pivot the load wheel 12L. The supporting bracket 13 can rotate around the center of the steering shaft 16 as a steering center. FIG. 8 shows the road wheel 12.
L is the maximum steering angle, and when the encoder 28 detects such a state, the steering motor 3
4L may be stopped, or it is of course possible to provide another mechanical stopper or the like to limit the steering angle. When the steering motor 34L is rotationally driven in a direction opposite to the direction shown in FIG.
Needless to say, L can also be steered in the opposite direction to the figure. Further, the center line of the road wheel 12L and the turning center of the steering shaft 16 can be eccentric by a distance e, which is a so-called kingpin offset. This means that, as shown in FIG.
In the case of running right beside, when the steering center is located at the center of the road wheel 12L, the wheel base becomes L. However, by providing the eccentric distance e as described above, L +
This is because a wheelbase of 2e can be secured. In addition, when the forklift 1 is stationary, the road wheel 12L is steered, that is, when the vehicle is stationary, so that the friction between the road wheel 12L and the ground can be reduced and rolling can be performed, so that the driving torque during steering can be reduced. This is because it can be planned. According to the present invention, as a result of adopting the above configuration, when the load wheel is rotatably supported, the center in the width direction of the load wheel and the center of the steering shaft are shifted by a predetermined distance toward the center of the vehicle body. Eccentric distance e
By setting, the steering torque can be reduced. The reduction of the steering torque as described above contributes to the miniaturization of various parts such as the steering motor, and the steering of the road wheel can be realized with extremely small dimensions without increasing the width of the straddle arm. A steering device can be provided, and a sufficient wheelbase can be ensured even when the vehicle is running sideways, and the effect of improving running stability and riding comfort can be obtained. Further, miniaturized components such as a steering motor, a timing pulley, and a steering shaft are housed and arranged in a straddle arm, and a hanging portion of a bracket having an inverted L-shaped cross section to which steering radiation is fixed is provided. By arranging them toward the outside of the vehicle body, it is possible to prevent a foreign substance or the like from entering from outside, and to obtain a remarkable effect that a gear, a timing belt and the like can be prevented from being damaged.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a reach type forklift. FIG. 2 is a front view of the present invention. FIG. 3 is a side view of the present invention. FIG. 4 is a plan view of the present invention. FIG. 5 is a plan view for explaining a wheel base. FIG. 6 is a plan view illustrating a conventional steering mechanism. FIG. 7 is a plan view illustrating a conventional steering mechanism. FIG. 8 is a plan view illustrating a steering state according to the present invention. [Description of Signs] 10 Straddle arm 12L Road wheel 12R Road wheel 13 Bracket 14 Bearing shaft 16 Steering shaft 19 Drive gear 20 Sector gear

Claims (1)

(57) [Claims] The left and right straddle arms are centered near the distal end of each of the left and right straddle arms and at the outer position in the vehicle body width direction, and the steering shaft parallel to the vertical axis in the vehicle body height direction is connected to the left and right straddle arms Each of the arms is rotatably supported, and the hanging portions of the inverted L-shaped bracket fixed to the steering shaft are respectively arranged toward the outside of the vehicle body, and the hanging portions are parallel to the horizontal axis in the vehicle width direction. And a support shaft rotatably supported on the support shaft at a predetermined distance from the center of the steering shaft to a center of the vehicle body in a widthwise direction of the load wheel at a predetermined distance from the center of the steering shaft. The gear is cut into a fan shape so as not to exceed the width of the fan, the gear with the arc side facing the center of the vehicle body is fixed to the bracket, and the drive gear meshing with the gear cut into the fan shape is Than notched gear shape in from the vehicle body center side, the steering apparatus of the road wheel in reach truck, characterized in that housed disposed on the left and right straddle arms within each.