JP2001191774A - Suspension device for industrial vehicle and reach type forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension device capable of extending a driver seat in the car width direction, lowering the flower of the driver seat, and enhancing the road surface fallow-up capability of wheels. SOLUTION: The suspension device 30 installed in a reach type forklift suspends a drive unit 31 having a driving steering wheel 19 and a caster 20 vertically movably in relation to a car body. A drive unit support 41 is rotatably connected to the drive unit 31 and the left part of a first rotation shaft 40 arranged in the front of the driver seat in an extending state in the car width direction. The first rotation shaft 40 is crossed with a reach cylinder 17 in the front from the driver seat. A caster arm 48 capable of swinging on a second rotation shaft 47 is operably connected to the left part of the first rotation shaft 40 through the engagement of a second arm part 54 with a transmission arm 46. Torque based on the wheel weight of the driving steering wheel 19 and that based on the wheel weight of the caster 20 are reversely inputted onto the right and left sides of the first rotation shaft 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device and a reach type forklift for an industrial vehicle in which a drive wheel and a driven wheel are vertically displaceably suspended on a vehicle body while allowing the vehicle body to swing in the roll direction. It is.

[0002]

2. Description of the Related Art For example, there is a reach-type forklift of a three-wheeled type having two front wheels and one rear wheel, and having a caster wheel adjacent to a drive steering wheel as a rear wheel at a predetermined distance in a vehicle width direction. The drive wheels and caster wheels are suspended from the vehicle body via a suspension device in a vertically displaceable state.

For example, Japanese Patent Laid-Open Publication No. Hei 8-164722 discloses a reach type forklift suspension device shown in FIG. An upright driver's seat 80 is provided at the rear right portion of the vehicle body, an operation panel 81 is provided in front of the driver's seat 80, and a steering wheel 82 is provided at the left side. The drive steering wheel 83 is located off the floor of the driver's seat 80 in the vehicle width direction, and the caster wheel 84 is located below the floor of the driver's seat 80. The drive steering wheel 83 is mounted below the drive unit gear 86 to which the driving force of the drive motor 85 is input.
6 and is displaceably supported integrally with a drive unit 87 having the same.

[0004] The drive unit 87 and the caster wheels 84 are suspended from the vehicle body via a parallel link mechanism 88 for operatively connecting them. The parallel link mechanism 88 supports the support link 9.
1, an upper link 92, a lower link 93, and a caster link 94. Each of the links 91 to 94 is connected by four axes 95 to 98 located at the vertices of a parallelogram. The parallel link mechanism 88 is set to a link ratio that distributes the load almost equally to the drive steering wheel 83 and the caster wheel 84,
A predetermined portion of the parallel link mechanism 88 is urged by the hydraulic cylinder 99 so that the drive steering wheel 83 is given a larger wheel load by the urging force of the hydraulic cylinder 99. Parallel link mechanism 8 according to the wheel weight of both wheels 83 and 84
8 rotates with respect to the vehicle body with the shafts 95 and 96 as fixed shafts,
Even if the mast device moves back and forth based on the driving of the reach cylinder (hydraulic cylinder) 100 and the vehicle center of gravity moves back and forth, the wheel weights of the two wheels 83 and 84 are appropriately distributed. It should be noted that there is also a device that urges using a suspension spring instead of the hydraulic cylinder 99.

Japanese Patent Application Laid-Open No. 8-156544 discloses that
A suspension device that does not employ a parallel link mechanism is disclosed. In this device, the suspension link is provided so as to be swingable about an axis arranged parallel to the vehicle front-rear direction, and the drive unit and caster wheels supported on both left and right sides of the suspension link can be vertically displaced with respect to the vehicle body Configuration.

[0006]

In the parallel link mechanism 88, a support base 91 for vertically supporting the drive motor 85 and the drive unit gear 86 is provided at the left end of the support link 91.
a extends horizontally above the floor surface 80a, while the lower link 93 and the caster link 94 that support the caster wheel 84 are arranged at a lower position below the floor of the driver's seat 80. Therefore, the arm portion 91b is bent downward from the right end of the support base portion 91a and extends downward, and the support link 71 is connected to the lower link 93 at the lower end portion of the arm portion 91b. Since the arm portion 91b is arranged on the right side of the drive unit 87, the space in the vehicle width direction of the driver's seat 80 is reduced accordingly. This problem is described in
The same applies to the swing-type device disclosed in Japanese Patent Application Publication No. 156544, as long as the drive unit is supported from the side (right side in the vehicle width direction) and operatively connected to the caster wheel side, the arm portion is disposed on the right side of the drive unit. The space had to be taken up, which reduced the width of the driver's seat.

As shown in FIG. 11, a reach cylinder 100 for moving the mast device back and forth is arranged at the center of the vehicle width at the bottom of the vehicle so as to extend in the front and rear direction.
The lower link 93 extending in the vehicle width direction is the reach cylinder 10.
It intersects 0 vertically. In addition, since it is necessary to secure a space for swinging the lower link 93 up and down between the reach cylinder 100 and the lower link 93, the height of the lower link 93 is relatively high, and the floor surface of the driver's seat 80 is compared. There was a problem that was getting high. In particular, in a reach-type forklift, the operator frequently gets on and off for cargo handling work. Therefore, a high floor surface of the driver's seat 80 tends to cause a decrease in work efficiency and fatigue of the driver. There was a request to lower the surface. This problem also occurred in the swing type device disclosed in Japanese Patent Application Laid-Open No. 8-156544.

Further, the parallel link mechanism 88 is connected to the drive steering wheel 8.
The input based on the wheel weight of No. 3 and the input based on the wheel weight of the caster wheel 84 stand still in a balanced posture. As shown in FIG. 11, in the parallel link mechanism 88, the plurality of links 91 to 94 are made of a beam-shaped relatively rigid member, and the parallel link mechanism 88 has a configuration that is hardly deformed such as bending or bending. . That is, the parallel link mechanism 88 does not have a structure having a spring rigidity to resiliently absorb two inputs from the wheels 83 and 84. For example, when a wheel rides on a convex portion or falls into a concave portion while traveling on an uneven road surface, the parallel link mechanism 88, the drive unit 87, and the caster wheel 84 try to maintain a stationary state due to inertia.
The movement of No. 8 was momentarily delayed, and the response as a suspension was not good. Therefore, as shown in FIG. 11, the caster spring 10 is provided between the caster link 94 and the lower link 93.
1 allows the caster wheel 84 to travel when traveling on uneven road surfaces.
To effectively absorb the vehicle vibration input from the vehicle. However, on the drive steering wheel 83 side, the support link 91
There is a problem that it is difficult to interpose a spring between the drive steering wheel 83 and the drive unit gear 86, and it is difficult to absorb vehicle vibration input from the drive steering wheel 83 when the drive steering wheel 83 travels on an uneven road surface. That is, it cannot be said that the road steering ability of the drive steering wheel 83 is sufficiently good.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to increase the width of the driver's seat in the vehicle width direction, lower the floor of the driver's seat, and improve the road following ability of the wheels. An object of the present invention is to provide an industrial vehicle suspension device and a reach type forklift that can be increased.

[0010]

In order to achieve the above object, according to the present invention, a floor surface of a driver's seat is disposed above a driven wheel of a pair of right and left driven wheels and driven wheels. And a drive unit having the drive wheels and the driven wheels are provided in an industrial vehicle in which the drive wheels are disposed at positions off the driver's seat floor and in the vehicle width direction, and the driven wheels swing in the roll direction of the vehicle body. In a suspension device for an industrial vehicle suspended vertically with respect to a vehicle body in an allowable state, a driving-side supporting means for supporting the drive unit and a driven-side supporting means for supporting the driven wheel are operatively connected to each other. A rotating shaft interposed rotatably between the driving wheels and the driven wheels, the two rotating forces based on the respective wheel loads of the driving wheels and the driven wheels being input in opposite directions on both axial sides, and interlocking with the rotating shaft. Of the driving side support means A movement starting point structure portion serving as a starting point of the position movement is arranged on the front side of the drive unit, and an operation connection mechanism including at least the rotation shaft for operatively connecting the drive side support means and the driven side support means is provided. And a reach driving device provided on the vehicle body for moving the cargo handling device back and forth with respect to the vehicle body, intersects ahead of the driver's seat. The term "both sides in the axial direction of the rotating shaft" does not mean both ends in the axial direction of the rotating shaft, but means two places separated by a distance that allows twisting in the axial direction of the rotating shaft.

Therefore, the rotating shaft is maintained in a torsion state because the opposite rotating force based on the respective wheel weights of the driving wheel and the driven wheel is input to both sides in the axial direction. Then, the driving wheel and the driven wheel are pressed and urged against the road surface by the torsional reaction force of the rotating shaft. For example, in comparison with a conventional device in which a drive wheel and a driven wheel are operatively connected through a parallel link mechanism formed of a rigid beam-shaped member, the rotation of the drive wheel and the driven wheel is not significantly affected by inertia of maintaining a stationary state. The disengagement of the torsion of the driving shaft makes it easier to displace semi-independently. Therefore, when an industrial vehicle equipped with the suspension device travels on an uneven road surface, the road surface followability of the drive wheel and the driven wheel is improved. Further, a movement starting point structure portion serving as a starting point of the displacement movement of the driving side support means is located on the front side of the drive unit, and a part of the drive side support means extending from the front with the movement starting point structure portion to support the drive unit is a drive unit. Located in front of. Accordingly, a space is opened at a position adjacent to the driven unit on the driven wheel side, so that the driver's seat can be widened in the vehicle width direction. Further, an operating connection mechanism including a rotation shaft for operatively connecting the driving-side support means and the driven-side support means intersects with the reach driving device in front of the driver's seat, so that the reach drive device and the operation connection mechanism are vertically moved. There is no need to secure the space required for the two-stage arrangement below the floor of the driver's seat. Therefore,
The floor of the driver's seat can be lowered.

According to a second aspect of the present invention, in the first aspect of the present invention, the one of the driving-side supporting means and the driven-side supporting means is connected to each other so as to be interlocked with each other; And a power transmission means for transmitting a rotational force about the support shaft when the other support means is displaced to the rotary shaft as a rotational force in the opposite direction. And

Therefore, a simple structure including the driving-side supporting means, the driven-side supporting means, the rotating shaft, the supporting shaft, and the power transmitting means is sufficient. Further, by selecting the link ratio of the power transmission means interposed between the one support means and the rotating shaft, it is easy to set the wheel weight distribution of the drive wheels and the driven wheels to a desired ratio. In other words, if the two support means are integrally connected to both sides of the rotating shaft in the axial direction, the wheel load distribution ratio is almost uniquely determined by the ratio of each distance between the driving wheel and the driven wheel to the rotating shaft. According to this configuration, the degree of freedom in setting the wheel load distribution ratio is increased by selecting the link ratio of the power transmission means. Further, it is possible to arrange the rotation shaft in a state where the driving wheel and the driven wheel are located on the same side (for example, the front side or the rear side of both wheels), and it is easy to layout the suspension device compactly.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the driving-side supporting means is arranged so that the driving wheel can swing in a plane orthogonal to the vehicle width direction. An arm that supports the drive unit and swings in conjunction with the rotation shaft.

Accordingly, when the drive wheels are vertically displaced with respect to the vehicle body, the arm supporting the drive unit swings in conjunction with the rotation shaft, so that the drive wheels swing in a plane orthogonal to the vehicle width direction. Therefore, when the drive wheel is vertically displaced with respect to the vehicle body, the drive wheel does not tilt with respect to the ground contact surface, and it is easy to prevent uneven wear of the tire of the drive wheel. Even if the driving wheel is a driving steering wheel, the driving wheel does not incline with respect to the ground contact surface at the time of straight forward steering with high frequency, and the tire of the driving steering wheel is less likely to be unevenly worn.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the driving-side supporting means operates in conjunction with a driving-side supporting member for supporting the drive unit and the rotating shaft. And a parallel link mechanism for moving the driving-side support member in parallel so as to be vertically displaceable while maintaining the attitude of the drive unit.

Accordingly, when the parallel link mechanism is operated in conjunction with the rotation axis, the drive-side support member moves in parallel while maintaining the attitude of the drive unit, and the drive wheel is vertically displaced. For this reason, it is easy to prevent uneven wear of the tire of the drive wheel without tilting the drive wheel with respect to the ground contact surface.
Further, even when the driving wheels are the driving steering wheels, the driving wheels do not tilt with respect to the ground contact surface irrespective of the steering angle of the driving steering wheels, so that it is also easy to prevent uneven wear of the tire.

According to the invention described in claim 5, according to claims 1-4
In the invention described in any one of the above, the rotation shaft is arranged to extend in the vehicle width direction. Therefore, there is a relatively large distance in the vehicle width direction between the drive wheel and the driven wheel that form a pair on the left and right, and if the rotating shaft that operatively connects the drive wheel and the driven wheel is arranged in a state that extends in the vehicle width direction, Since the rotating shaft is relatively long, it is easy to twist. Therefore, a relatively large amount of displacement of the wheel when the torsion of the rotation shaft is released can be secured relatively large, and it is easy to enhance the road surface followability of the drive wheel and the driven wheel.

According to a sixth aspect of the present invention, a reach type forklift is provided with the suspension device according to any one of the first to fifth aspects. Therefore, according to this reach type forklift, the same operation as the invention described in any one of claims 1 to 5 can be obtained.

[0020]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIGS. 2 and 3, a reach type forklift 10 (hereinafter referred to as a forklift) as an industrial vehicle is a three-wheeled vehicle having two front wheels and one rear wheel. A pair of left and right reach legs 12 extend forward from a front portion of the vehicle body 11. A driver's seat (driver's cab) 13 of a standing type is provided at a rear right portion of the vehicle body 11. An instrument panel 11A on the front side of the driver's seat 13 is provided with an operation lever 14 for cargo handling operation and the like, and a steering wheel (steering wheel) 15 is provided on an upper surface of a storage box 11B provided on the left side of the driver's seat 13. Is provided.

A mast device 16 is mounted on the vehicle body 11 so as to be movable in the front-rear direction along a pair of left and right reach legs 12. The mast device 16 is connected to a piston rod 17a of a reach cylinder (hydraulic cylinder) 17 as a reach drive device disposed at the center of the vehicle body 11 in the bottom vehicle width direction. By operating the reach lever of the operation lever 14, hydraulic oil is supplied from the oil control valve (not shown) to the reach cylinder 17, and the piston rod 17a is driven to expand and contract, thereby the mast device 16
Moves back and forth within a predetermined stroke range.

The left and right front wheels 18 are driven wheels and are attached to the distal ends of the left and right reach legs 12, respectively. Driving wheel (hereinafter referred to as driving steering wheel) 1 in which one rear wheel also serves as a steering wheel
The drive steering wheel 19 is positioned offset to the left in the vehicle width direction, and a caster 20 as a driven wheel that is paired with the drive steering wheel 19 on the right and left is provided on the right side at a predetermined distance. ing.

As shown in FIGS. 1, 4, and 6, a vehicle body frame 21 constituting a vehicle body 11 includes a front frame portion 22 and a rear frame portion 23 disposed in front and rear of the vehicle body, and both frame portions 22, 23. It has a support frame portion 24 that is connected back and forth at a substantially central position in the width direction and extends along a division line between the driver's seat 13 and the storage box 11B. A bottom plate 25 for connecting the left and right reach legs 12 to each other is welded to the lower surfaces thereof. A side surface and a rear surface (rear surface) of the vehicle body 11 are covered by a panel 26 attached to the vehicle body frame 21.

As shown in FIG. 4, a battery storage chamber 27 is formed in a lower front portion of the vehicle body 11 with a front opening. The battery 28 is accommodated in the battery accommodation room 27 in a state where the battery 28 is arranged almost completely in the vehicle width direction.

The suspension device 3 is provided at the rear of the vehicle body 11.
0 is equipped. The suspension device 30 sets the drive steering wheels 1 in a state where the vehicle body 11 is allowed to swing in the roll direction.
9 and casters 20 are suspended from the body frame 21 so as to be vertically displaceable.

As shown in FIGS. 1, 4, and 5, the suspension device 30 includes a drive unit 31 having a drive steering wheel 19 mounted on a lower portion thereof and a caster 20 so that the body 11 can swing in the roll direction. A suspension mechanism 30 </ b> A is provided as an operation connection mechanism that is operably connected to the apparatus 11 in a vertically displaceable state.

The suspension mechanism 30A includes a drive unit support 41 as a drive side support means and an arm for supporting the drive unit 31;
A first rotation shaft 40 as a rotation shaft rotatably supported with respect to the first rotation shaft, a second rotation shaft 47 as a support shaft, and a caster arm 48 constituting driven side support means for supporting the casters 20. . The first rotating shaft 40 is disposed at the center of the vehicle width at a length of about の or more of the vehicle width, and has four bearings 42 attached to the vehicle body frame 21 at both ends and two central positions, for a total of four locations. Supported. The second rotating shaft 47 is the first
The first rotating shaft 40 is disposed at a position close to the right side of the rotating shaft 40 in parallel with the first rotating shaft 40, and is supported at both ends by two bearings 52 attached to the vehicle body frame 21. The bearing 42 in this example is a bearing bracket supported by the frame and a bush (cylindrical) inserted into the hole.
Consists of

The first rotary shaft 40 is disposed at a position higher than the reach cylinder 17 in front of the driver's seat 13. Therefore, the first rotating shaft 40 crosses the reach cylinder 17 in front of the driver's seat 13. The second rotating shaft 47 is the driver's seat 1
3 is disposed below the floor plate 13a.

The base (lower end) 43 of the drive unit support 41 is fixed to the first rotating shaft 40 by spline fitting or serration so as to be integrally rotatable.
The drive unit support 41 can swing about a first rotation shaft 40 in a plane orthogonal to the vehicle width direction. In the present embodiment, the fixed connection portion between the base 43 of the drive unit support 41 and the first rotating shaft 40 is
The drive unit support 41 serves as a motion starting point structure portion that serves as a motion starting point of the rocking motion.

As shown in FIG. 4, the drive unit support 41 has a substantially crank shape in a side view, and has an arm 44 extending upward from the base 43 and a support base 45 extending substantially horizontally rearward from the upper end of the arm 44. . Drive unit 31
Is mounted on the support base 45. The arm portion 44 is located in a state of extending vertically to the front side of the drive unit 31 so as to support the drive unit 31 from the front.

The drive unit 31 includes a drive motor 32 mounted on the upper surface of the support base 45 and a drive motor 32 mounted on the support base 4.
And a gear housing 33 rotatably supported in a horizontal plane on a lower surface of the gear housing 5. The drive steering wheel 19 is rotatably supported below the gear housing 33. The gear wheel 33a fixed to the upper part of the gear housing 33 meshes with a gear portion (both not shown) at the lower end of the steering shaft connected to the handle 15 by a universal joint (not shown). The drive steering wheel 19 is steered in accordance with the rotation operation of.

On the other hand, as shown in FIGS. 1, 5 and 6, the base 53 of the caster arm 48 is connected to the second rotary shaft 47 so as to be integrally rotatable by spline fitting or serration connection. It can swing up and down around the two rotation shafts 47. Caster arm 4
Reference numeral 8 extends from the base 53 so as to bend to the rear right side.
0 is rotatably supported in a horizontal plane. Caster 2
0 has one set of caster wheels 35.

A base 49 of a transmission arm 46 is fixed to the right side of the first rotating shaft 40 by spline fitting or serration connection, and is connected to the first rotating shaft 40 so as to be integrally rotatable. A first arm portion 50 extends obliquely backward from the base portion 49 of the transmission arm 46 to the lower side in the rotation radial direction thereof. A pair of left and right protrusions 5 is provided from the rear surface of the first arm 50.
1 projects obliquely rearward and upward. Caster arm 48
A second arm portion 54 extends obliquely upward and forward from a base portion near the base portion 53, and abuts the projection 51 on the lower surface thereof. The rotational power of the caster arm 48 is the second arm 5
4, via the projection 51 and the first arm 50,
It is transmitted to the rotating shaft 40 as a rotating force in the opposite direction. In the present embodiment, the power transmission means is configured by the transmission arm 46 and the second arm portion 54. The driven-side support means is composed of the caster arm 48 and the components 46 and 54 of the power transmission means.

When the drive steering wheel 19 and the caster wheel 35 are in contact with the road surface, a force based on the wheel weight of the drive steering wheel 19 (more precisely, the drag received from the road surface by the wheel load) is applied to the left portion of the first rotary shaft 40. Is input as the clockwise rotation force in FIG. 6, and the force based on the wheel load of the caster wheel 35 is the first force.
The rotation force in the counterclockwise direction in FIG. That is, the rotational force input to the left side portion of the first rotating shaft 40 via the drive unit support 41 and the caster arm 48 to the second arm portion 54,
The rotational force input to the right side portion via the protrusion 51 and the first arm portion 50 is opposite to each other.

The suspension device 30 includes a bracket 56 provided on the rear surface of the front frame portion 22.
And a wheel load adjusting spring 58 interposed between a bracket 57 fixed to the upper surface of the support base 45 of the drive unit support 41. The wheel load adjusting spring 58 is disposed in an oblique position in which the axis is parallel to the tangent direction of the swing locus of the drive unit support 41, and the elastic force of the spring 58 adjusts the drive unit support 41.
Is urged downward.

The suspension mechanism 30A calculates the load obtained by subtracting the contribution of the urging force of the wheel weight adjusting spring 58 from the rear load of the vehicle supported by the rear two wheels by the drive steering wheel 19 and the caster wheels 35. The link ratio is set so as to be distributed almost equally. That is, the distance from the second rotation shaft 47 to the caster 20 is:
The value obtained by multiplying the ratio obtained by dividing the distance from the first rotation shaft 40 to the tip contact portion of the projection 51 by the distance from the second rotation shaft 47 to the tip contact portion of the projection 51 is the value of the drive from the first rotation shaft 40. The distance is set to be substantially equal to the distance to the steered wheels 19.

Although the wheel weight distribution ratio of the drive steering wheel 19 and the caster wheel 35 via the suspension mechanism 30A is substantially equal, the biasing force of the wheel weight adjusting spring 58 is added as the wheel weight of the drive steering wheel 19 extra. The wheel weight of the drive steering wheel 19 is always larger than the wheel weight of the caster wheel 35 by a certain value.

When the mast device 16 reaches the foremost position with the maximum load, the rear load of the vehicle becomes considerably small, but the wheel weight corresponding to the urging force of the wheel load adjusting spring 58 becomes excessive toward the drive steering wheel 19. , The wheel weight of the drive steering wheel 19 is always secured to a value equal to or more than the minimum necessary. Therefore, the slip of the drive steering wheel 19 is less likely to occur.

When the mast device 16 is empty and in the rearmost position, the rear load of the vehicle becomes extremely large.
A load having a value obtained by subtracting a constant value corresponding to the urging force of the wheel load adjusting spring 58 from the rear load is distributed to the two wheels 19 and 20 almost equally, so that the wheel load distribution ratio of the casters 20 is increased. Therefore, a wheel load exceeding the specified value is not applied to the drive steering wheel 19.

The first rotating shaft 40 has a rotational force based on the wheel load of the drive steering wheel 19 input to both left and right sides thereof, and a caster 2.
Since the rotational force based on the zero wheel load is in the opposite direction, it is maintained in a twisted state. The torsional reaction force of the first rotating shaft 40 is balanced with the respective wheel loads of the drive steering wheel 19 and the casters 20.

The first rotary shaft 40 is rotated so that two inputs (rotational forces) input from both right and left sides thereof are balanced, and the drive steering wheel 19 and the caster 20 are displaced upward with respect to the vehicle body 11 to drive. The wheel weights of the steered wheels 19 and the casters 20 are distributed to a suitable wheel load ratio.

The amount of torsion of the first rotary shaft 40 increases as the value of the two inputs from the left and right sides increases, and the torsional reaction force of the first rotary shaft 40 increases as the amount of twist increases.
Both wheels 19 and 20 are urged to press the road surface by the torsional reaction force of the first rotating shaft 40. Strictly speaking, the drive unit support 41 and the drive unit 31
Also contributes to the wheel weight of the drive steering wheel 19, and the weight of the caster arm 48 also contributes to the wheel weight of the caster 20.

The drive steering wheel 19 and the caster 20 are urged on the road surface by the torsional reaction force of the first rotating shaft 40. For example, when the drive steering wheel 19 rides on the convex portion during traveling of the forklift, the caster 20 and the caster arm 48 try to keep stationary due to the inertia force, but the first rotation shaft 40 of the drive steering wheel 19 is twisted momentarily. And is displaced upward so as to follow the convex portion. Then, the first rotary shaft 40 is rotated to a position where the two inputs on both the left and right sides are balanced while releasing the excess torsion, so that the caster 20 is displaced downward with respect to the vehicle body 11 with a slight delay, and the wheel load of the caster 20 is reduced. Increase.

Further, when the drive steering wheel 19 falls into the concave portion, the caster 20 and the caster arm 48 try to keep stationary due to the inertial force, but the first rotation for urging the drive steering wheel 19 to the road surface. When the twist of the shaft 40 is released, the drive steering wheel 19 follows the concave portion. And the first
By rotating the rotating shaft 40 to a position where the two inputs on both the left and right sides are balanced while returning the twist, the caster 20 is rotated.
Is slightly displaced upward with respect to the vehicle body 11 and the caster 2
Zero wheel weight is reduced.

The same applies to the case where the caster 20 rides on the convex portion or falls into the concave portion, and the first rotating shaft 40 is twisted or released, whereby the followability of the caster 20 to the road surface is enhanced. Accordingly, the road surface followability of the drive steering wheels 19 and the casters 20 is improved.

As described in detail above, according to the present embodiment,
The following effects can be obtained. (1) A structure in which the suspension mechanism 30A is arranged in a substantially U-shape in plan view to bypass the front, and the movement starting point structure of the drive unit support 41 is the drive unit 3
1 ahead. Therefore, the drive unit support 41 is arranged to support the drive unit 31 from the front, and the arm 44 of the drive unit support 41 is provided.
Are arranged so as to extend up and down on the front side of the drive unit 31, so that the driver's seat 13 can be widened in the vehicle width direction to a space where the arm portion was conventionally arranged beside (to the right of) the drive unit. .

(2) A structure in which the suspension mechanism 30A is arranged in a substantially U-shape in plan view to bypass the front.
The rotating shaft 40 intersects the reach cylinder 17 ahead of the driver's seat 13. Conventionally, the components (lower link, etc.) of the suspension device are arranged below the floor and intersect with the reach cylinder below the floor, so that the floor of the driver's seat 13 is raised. On the other hand, according to this embodiment, since the first rotating shaft 40 does not pass below the floor and intersects with the reach cylinder 17 in front of the driver's seat 13, the floor of the driver's seat 13 can be lowered. it can.

(3) Since the first rotating shaft 40 is kept twisted when both wheels 19 and 20 are in contact with the road surface,
Due to the torsional reaction force of the first rotating shaft 40, the two wheels 19, 20 are urged in a direction pressed against the road surface. The conventional parallel link mechanism type device (FIG. 11) has a structure in which a beam-shaped relatively rigid member is used and is hardly bent, and the conventional swing type device has a structure in which the shaft is hardly twisted. Was. On the other hand, in the present embodiment, the first rotating shaft 40 is a relatively long shaft arranged so as to extend along the vehicle width direction, and the rotating force in the opposite direction is input from both sides in the axial direction, and the first rotating shaft 40 is easily twisted. Therefore, the torsional reaction force can be used for urging the two wheels 19 and 20. Therefore, when the forklift 10 travels,
Road followability of the two wheels 19 and 20 can be improved. Therefore, traveling stability when traveling on uneven road surfaces can be improved as compared with the related art.

(4) Since a parallel link mechanism is not interposed between the drive steerable wheels 19 and the casters 20 and the suspension mechanism 30A utilizing the rotation of the rotating shaft 40 is employed, the conventional parallel link mechanism type is used. As compared with the prior art, the suspension device 30 can have a simple structure while having the wheel load distribution function as in the related art. Further, since the turning shaft can be arranged in a state where the drive steered wheels 19 and the casters 20 are located on the same side with respect to the turning shaft (the first turning shaft 40), the suspension device 30 can be laid out compactly.

(5) The drive unit 31 is supported from the front by the drive unit support 41 that swings about the first rotation shaft 40, and the drive steering wheel 19 swings in a plane perpendicular to the vehicle width direction. Therefore, the drive steering wheel 19 does not incline with respect to the ground contact surface when traveling straight, and it is possible to easily prevent uneven wear of the tire of the drive steering wheel 19. That is, in the conventional structure in which the drive unit is supported from the side, the drive steering wheel is tilted to the side even when traveling straight, but since the drive unit 31 is supported from the front and the drive steering wheel 19 swings in the traveling direction, Uneven wear of the tire is unlikely to occur.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. This embodiment is different from the first embodiment in that the drive unit support is connected to the first rotation shaft 40 so as to be able to move up and down in parallel using a parallel link mechanism. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only particularly different components will be described.

The first rotating shaft 40 has the same arrangement position and assembling structure as in the first embodiment. The first rotating shaft 40 is located in a state extending in the vehicle width direction in front of the driver's seat 13 and the drive unit 31, and the vehicle body frame. 21 is rotatably supported by a plurality of bearings 42. The first rotation shaft 40 intersects the reach cylinder 17 above. In this suspension device 60, the drive unit support 62 as a drive-side support member has a substantially L-shape in side view,
It has a support base 66 for supporting the drive unit 31 and an arm 65 bent downward at a substantially right angle from the front end of the support base 66.

The drive unit support 62 is supported by the first rotating shaft 40 and the body frame 21 via a parallel link mechanism 61 so as to be vertically displaceable. The parallel link mechanism 61 includes a drive unit support 62, a pair of left and right upper links 63 connected to upper left and right sides of the drive unit support 62, and a pair of left and right lower links 64 connected to lower left and right sides thereof.

The left and right upper links 63 are rotatably connected at their base ends to a bracket 67 attached to the rear surface of the front frame section 22 via a shaft 68, and have their front ends at the drive unit support 62. Is rotatably connected to the side of the support base 66 via a shaft 69. The base ends of the left and right lower links 64 are integrally rotatably connected to the first rotating shaft 40, and the front ends of the lower links 64 are connected to the drive unit support 62.
Is rotatably connected to the lower end of the arm 65 via a shaft 70.

The shafts 40, 68, 69, 70 are arranged so as to form a parallelogram in side view, and the drive unit support 62 can be vertically displaced by a part of the drive unit support 62 and both links 63, 64 and the like. A parallel link mechanism 61 for making a parallel movement is formed. For this reason, when the parallel link mechanism 61 is operated, the drive unit 31 is vertically moved in parallel with the drive unit support 62 while maintaining the vertical posture. In this embodiment, the drive unit support 62 of the parallel link mechanism 61 is used.
The movement starting point structure is constituted by the mechanical structure other than itself. Further, the parallel link mechanism 61 and the drive unit support 62 constitute driving side support means.

Also in this embodiment, the arm 65 extending downward from the support base 66 is located on the front side of the drive unit 31. The wheel load adjusting spring 58 is disposed substantially perpendicularly to the support base 66 such that the axial direction thereof is substantially parallel to the parallel movement direction of the drive unit support 62. The operation connecting structure between them is the same as that of the first embodiment as shown in FIG. In this case, the suspension mechanism 60A is configured to distribute the load of a value obtained by subtracting the biasing force contribution of the wheel load adjusting spring 58 from the rear load of the vehicle to the drive steering wheels 19 and the casters 20 almost equally. . That is, when the wheel weight of the caster 20 is substantially equal to the wheel weight obtained by subtracting the biasing force contribution of the wheel weight adjusting spring 58 from the wheel weight of the drive steering wheel 19, the suspension mechanism 60 </ b> A is on the left and right sides of the first rotating shaft 40. The link ratio is set such that the two rotational forces input in opposite directions are balanced.

Therefore, according to the second embodiment, the following effects can be obtained in addition to the effects (1) to (5) similar to the first embodiment. (6) With the adoption of the parallel link mechanism 61, the drive unit 31 translates (moves) up and down while maintaining its posture.
9 is not inclined, and uneven wear of the tire can be prevented.

(7) Since the parallel movement system employs the parallel link mechanism 61, the amount of displacement of the drive unit 31 in the vehicle front-rear direction is relatively small as compared with the swing system employed in the first embodiment. The space required for housing the drive unit 31 required to prevent interference with the drive unit 31 can be relatively reduced.

The embodiment is not limited to the above-described configuration, and can be implemented, for example, in the following manner. ○ Drive wheel (drive steering wheel 19) and driven wheel (caster 2)
The rotation axis for inputting the two rotational forces based on the respective wheel weights of 0) to both sides in the axial direction can be a torsion bar. For example, as shown in FIG. 9, a first rotating shaft 72 as a rotating shaft is provided with a small-diameter portion
It consists of a torsion bar having a. Therefore, the spring constant of the spring function provided by the torsion of the first rotating shaft 72 can be set small, and the road surface following properties of the two wheels 19 and 20 can be further enhanced. Of course, in the apparatus employing the parallel link mechanism of the second embodiment, the rotation axis may be a torsion bar.

A spring for absorbing the vibration input to the caster 20 from the road surface may be provided on the operation connection path of the suspension mechanism. For example, in the first and second embodiments, a caster spring 75 is interposed between the first arm 50 and the second arm 54 as shown in FIG. According to this configuration, the fine vibration input to the caster 20 from the road surface is applied to the spring (caster spring 59).
Therefore, the vehicle body 11 is unlikely to vibrate finely.

It is also possible to adopt a structure in which a support member corresponding to the caster link of the conventional apparatus is connected and supported below the caster arm via a spring (caster spring), and the caster is supported by this support member. With this configuration,
Similar to the structure of FIG. 9, the spring absorbs the vibration input to the caster from the road surface, and the vehicle body is less likely to vibrate finely.

The drive-side support member (drive unit support) is connected via a power transmission means so that the rotation direction can be transmitted in the direction opposite to the rotation axis, and the driven-side support member (caster arm) is connected to the rotation shaft. They may be connected so as to be integrally rotatable.

The power transmission means for inputting a rotational force in the opposite direction to both axial sides of the rotating shaft is not limited to the structures of the above embodiments. For example, a structure may be adopted in which a gear mechanism is adopted, and the rotation of the drive unit support or the caster arm is reversed through the gear mechanism and input to the rotation shaft.

The distribution ratio (link ratio) of the rear load of the vehicle of the suspension mechanism is not limited to substantially equal. When the vehicle wheel center (including the biasing force of the wheel load adjusting spring) is located at the frontmost position, the driving wheel (drive steering wheel 19) is secured with a minimum wheel load and the vehicle center of gravity is located at the rearmost position. An appropriate distribution ratio (link ratio) can be set so that the wheel load of the driven wheels (casters 20) can be increased so that the drive wheels (drive steering wheels 19) do not receive a wheel load exceeding a specified value (allowable value).

The supporting shaft is not limited to a rotating shaft such as the second rotating shaft 47. It may be a support shaft that swingably supports the driven-side support member (caster arm 48). The support shaft may be a pair of pins that support the base of the caster arm 48 from both left and right sides. In short, any support shaft is sufficient as long as the support shaft rotatably supports the driven-side support member.

The caster arm 48 may be supported so as to be able to move up and down in parallel via a parallel link mechanism interlocked with the second rotating shaft. In this case, an arm portion is provided that protrudes radially from the second rotation shaft, and this arm portion is connected to the first arm of the transmission arm.
Make contact with the projection on the arm. In this case, the parallel movement of the caster arm can be converted into rotation and transmitted to the first rotation shaft 40 (72) as a reverse rotation force.

The drive wheel does not need to be a drive steering wheel. Driving wheels that do not also serve as steering wheels may be used. In this case, a driven wheel that is not a caster is arranged below the driver's seat. As long as the driving wheels do not also serve as the steering wheels, the tires do not wear unevenly even in the swing type as in the first embodiment.

In the first and second embodiments, a hydraulic cylinder such as a hydraulic cylinder or a pneumatic cylinder may be used in place of the spring for adjusting the wheel load. ○ The drive for reach is not limited to the hydraulic cylinder.
For example, a power cylinder driven by a motor may be used. In short, any device capable of moving the cargo handling device back and forth is sufficient.

The industrial vehicle provided with the suspension device may be any industrial vehicle in which the left and right front wheels or the left and right rear wheels are composed of driving wheels and driven wheels and a driver's seat is provided above the driven wheels. It is not limited to. An industrial vehicle other than a forklift having a function of moving the cargo handling device back and forth may be used.

The technical ideas other than the claims that can be grasped from the embodiment and other examples are described below. (1) The operation coupling mechanism (suspension mechanism 30A) according to claim 2, which includes the drive-side support means, the driven-side support means, and the rotation shaft for operatively connecting the drive unit and the driven wheel. An elastic means (caster spring 75) is interposed at a position closer to the driven wheel than the rotation shaft on the connection path.

In this case, the vibration input to the driven wheel from the road surface is absorbed by the elastic means, so that the fine vibration of the vehicle body can be reduced. Further, since the elastic means is interposed on the operation connection path of the operation connection mechanism, the elastic means does not exert an urging force to increase the wheel weight of the driven wheel, and does not affect the adjustment of the wheel load distribution between the drive wheel and the driven wheel. The elastic means is not limited to a spring, but may be rubber or a damper (cylinder).

(2) In claim 1 or 2, the floor of the driver's seat is disposed above the driven wheel, and the drive wheel is disposed at a position deviated from the floor of the driver's seat in the vehicle width direction. An industrial vehicle, wherein the rotation axis is arranged in a vehicle width direction in front of a driver's seat, and the driving-side support means and the driven-side support means extend in a direction intersecting with the axis direction of the rotation axis. And an operation connection mechanism for operatively connecting the drive unit and the driven wheel is disposed in a substantially U-shape in plan view, bypassing the front of the driver's seat.

In this case, since the drive unit is supported from the front by the drive-side support means, the driver's seat can be widened in the vehicle width direction. Even if the drive-side support means is of the swing type, uneven wear of the tire of the drive wheel hardly occurs.

(3) In any one of claims 1 to 4,
The rotating shaft is located on the front side of the drive unit, and an arm portion that supports the drive unit from the front by the drive-side supporting means that can be interlocked with the rotating shaft extends forward of the drive unit.

In this case, since the arm of the drive-side support means for supporting the drive unit from the front extends on the front side of the drive unit, there is no need to provide a space for arranging the arm at the position adjacent to the driven wheel side of the drive unit. The driver's seat can be widened in the vehicle width direction.

(4) In any one of the first to sixth aspects and the technical ideas (1) to (3), the rotating shaft is a torsion bar. According to this configuration, the rotation shaft is easily twisted, and the road surface followability of the drive wheels can be further improved.

[0078]

As described in detail above, according to the first to sixth aspects of the present invention, the space in the vehicle width direction of the driver's seat can be widened, the floor of the driver's seat can be lowered, and the ability of the wheels to follow the road surface can be improved. be able to.

According to the second and sixth aspects of the present invention, in addition to the effects of the first aspect, the suspension apparatus is a suspension apparatus that displaces a wheel by using the rotation of a rotation shaft, so that the apparatus structure is simple. In addition, it is easy to set the wheel weight distribution between the drive wheel and the driven wheel, and the rotary shaft can be arranged in a state where the drive wheel and the driven wheel are located on the same side, so that the suspension device can be laid out compactly. it can.

According to the third and sixth aspects of the present invention, in addition to the effects of the first or second aspect, the drive wheels oscillate in a plane perpendicular to the vehicle width direction. Uneven wear is unlikely to occur.

According to the fourth and sixth aspects of the invention, in addition to the effects of the first or second aspect, the driving wheels are driven and steered by the parallel link mechanism because the driving wheels move up and down in parallel. Irrespective of the absence, uneven wear of the tire of the drive wheel can be prevented.

According to the fifth and sixth aspects of the present invention, in addition to the effects of any one of the first to fourth aspects, the rotating shaft extending in the vehicle width direction is relatively long and easily twisted. Road followability of the drive wheel and the driven wheel can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a partially broken schematic plan view showing a suspension device according to a first embodiment.

FIG. 2 is a side view of the reach type forklift.

FIG. 3 is a plan view of a reach type forklift.

FIG. 4 is a schematic side view showing a suspension device.

FIG. 5 is a schematic rear view showing the suspension device.

FIG. 6 is a schematic side view showing a caster side structure of the suspension device.

FIG. 7 is a schematic side view showing a suspension device according to a second embodiment.

FIG. 8 is a partially cutaway plan view showing a suspension device.

FIG. 9 is a partially cut-away schematic plan view showing another example of a suspension device.

FIG. 10 is a schematic side view of a caster side structure of another example of a suspension device.

FIG. 11 is a rear view showing a conventional suspension device.

[Explanation of symbols]

10 ... Reach type forklift as an industrial vehicle, 11
... Car body, 13 ... Driver's seat, 13a ... Floor board, 16 ... Mast device as cargo handling device, 17 ... Reach cylinder as reach drive device, 19 ... Drive steering wheel as drive wheel, 2
0: casters as driven wheels, 21: body frame, 3
0, 60: Suspension device, 30A, 60A: Suspension mechanism as an operation connection mechanism, 31: Drive unit, 40, 72: First rotation axis as rotation axis, 4
1 ... Drive-side support means, drive unit support as arm and drive-side support member, 46 ... Transmission arm constituting power transmission means, 47 ... Second rotary shaft as support shaft,
48 ... caster arms constituting driven side support means, 54
.., A second arm part constituting the power transmission means, 58... A wheel load adjusting spring constituting the suspension device, 61.
A parallel link mechanism constituting the drive-side support means and the movement starting point structure, 62... A drive unit support constituting the drive-side support means and the movement start point structure and serving as a drive-side support member.

Claims (6)

[Claims] 1. A driver's seat floor is disposed above a driven wheel among a pair of right and left driven wheels and driven wheels, and the drive wheel is located at a position deviated from the driver's seat floor in a vehicle width direction. A suspension device for an industrial vehicle, which is mounted on an industrial vehicle in which a drive unit having the drive wheels and the driven wheel are suspended vertically with respect to the vehicle body so as to allow swinging of the vehicle body in the roll direction. In the above, the drive-side support means for supporting the drive unit and the driven-side support means for supporting the driven wheel are rotatably interposed between the two in a state where they are operatively connected to each other, and the respective wheel loads of the drive wheel and the driven wheel The drive unit includes a rotation shaft in which two rotational forces based on the rotation axis are input in opposite directions on both sides in the axial direction, and a movement starting point structure portion serving as a starting point of a displacement movement of the drive-side support means interlocked with the rotation shaft is provided. in front Together they are arranged,
An operation connection mechanism including at least the rotating shaft for operatively connecting the drive side support means and the driven side support means,
A suspension device for an industrial vehicle that intersects a reach drive device provided on a vehicle body to move the cargo handling device back and forth with respect to the vehicle body in front of the driver's seat. 2. The rotating shaft, wherein one of the driving-side support means and the driven-side support means is operably connected to each other;
A power transmission mechanism for transmitting a rotational force about the support shaft when the other support means is displaced as a rotational force in a direction opposite to the rotational axis when the other support means is displaced; The suspension device for an industrial vehicle according to claim 1, further comprising: 3. The drive-side support means is an arm that supports the drive unit so that the drive wheels can swing in a plane orthogonal to the vehicle width direction, and swings in conjunction with the rotation shaft. The suspension device for an industrial vehicle according to claim 1 or 2. 4. The drive-side support means operates in conjunction with a drive-side support member that supports the drive unit, and the drive-side support member moves up and down while maintaining the drive-unit posture. And a parallel link mechanism for performing parallel movement as much as possible.
3. The suspension device for an industrial vehicle according to claim 1. 5. The suspension device for an industrial vehicle according to claim 1, wherein the rotation shaft is arranged to extend in a vehicle width direction. 6. A reach type forklift equipped with the suspension device according to claim 1.