JP2001105818A - Suspension lock device for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support a cylinder for locking without extending an exclusive bracket to the link for constituting a link mechanism for suspending a drive unit having a drive wheel and a driven unit having a driven wheel to a car body and prevent the rattle of the car body at the locking time of the cylinder device for locking. SOLUTION: In the rear suspension device 20 with a lock function, a drive unit 21 having a drive wheel 3 and a caster unit 22 having an auxiliary wheel 4 are suspended through a parallel link mechanism 24 against a car body frame so as to allow the swing of the roll direction of the car body. A suspension function is locked by the lock of the cylinder device 44 for locking interposed between a car body frame 23 and support link 26. The cylinder for locking 44 is connected to the bracket for connecting 26e of the upper surface of the support stand 26a arranged nearly horizontally of a support link 26 for supporting the drive unit 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension in which a driving wheel and a driven wheel forming a pair on the left and right are suspended from a vehicle body via a link mechanism so as to be able to swing in the roll direction of the vehicle body. The present invention relates to a suspension lock device for an industrial vehicle in which a locking cylinder device for restricting (locking) rocking of a vehicle body in a roll direction is interposed between a link mechanism and a vehicle body frame.

[0002]

2. Description of the Related Art For example, some reach-type forklifts are of a three-wheeled type having two front wheels and one rear wheel, and are provided with auxiliary wheels adjacent to one rear driving wheel. The drive wheels and the auxiliary wheels are suspended from the vehicle body via a rear suspension device.

Conventionally, for example, a suspension device shown in FIG. 6 has been employed. The drive unit 72 supporting the drive wheels 71 and the auxiliary wheels (caster wheels) 73 are suspended on the vehicle body frame 70 via the parallel link mechanism 74.
The parallel link mechanism 74 includes an upper link 75, a support link 76, a lower link 77, and a caster link 78,
Each link 75-78 is connected by four axes 79-82 located at the vertices of a parallelogram. The driving wheel 71 is pressed in the ground contact direction by the pressing force of the suspension spring 83 that urges a predetermined portion of the parallel link mechanism 74. The auxiliary wheel 73 is connected to the caster link 78 by a spring 84.
Is supported through. The support link 76 has a substantially inverted L-shape when viewed from the rear, and has a support base 76 a on which the traveling motor 85 is disposed.
And an arm 76b that is bent substantially at right angles from the right end of the support base 76a and extends downward. The parallel link mechanism 74 moves the shafts 79 and 8 in accordance with the wheel loads (wheel pressure) of the two wheels 71 and 73.
0 is fixed with respect to the vehicle body, and even if the center of gravity of the vehicle changes back and forth in accordance with the forward and backward movement of the mast, both wheels 71 , 7
The wheel weight of No. 3 was appropriately distributed.

For example, JP-A-6-191250, JP-A-6-191251 and JP-A-10-2979
Japanese Patent Publication No. 00-2004 and the like disclose that a cylinder device (locking cylinder device) is interposed between a vehicle body frame and a parallel link mechanism so that a predetermined lock condition is established based on a detection value of a sensor provided on the vehicle body. A suspension device with a lock function that restricts rocking of a vehicle body in a roll direction by closing an opening / closing valve of a working fluid and locking a cylinder device so that the cylinder device cannot expand and contract is disclosed. Locking conditions for locking the cylinder device include, for example, when the tilting acceleration detected by the acceleration sensor is equal to or more than a predetermined value, or when the vehicle speed detected by the vehicle speed sensor performs a cargo handling operation in which the vehicle tends to be unstable. When the vehicle is at a low vehicle speed, the cylinder device is locked when such a condition is satisfied to stabilize the vehicle body.

According to the former two of these prior arts, the locking cylinder device 86 is connected to the parallel link mechanism 74 by a support link 76 as shown in FIG. As shown in FIG. 7, a pedestal 76c for mounting a traveling motor 85 is formed at the front end (left end) of the support base 76a in the support link 76.
A dedicated bracket 76d for supporting the cylinder is formed so as to extend further outward (leftward) in the vehicle width direction from the tip (left end) portion of 6c. A connection bracket 76e for connecting to the lower end of the rod of the locking cylinder device 86 is formed on the upper surface of the special bracket 76d. As shown in FIG. 6, the lock cylinder device 86 includes a support bracket 87 extending from the vehicle body frame and a dedicated bracket 76d.
And both ends were connected. The reason why the dedicated bracket 76d is extended is that the locking cylinder device 86 is provided with a distance (link arm length) from the rotation axis of the support link 76 to reduce the load applied to the locking cylinder device 86. In order to obtain an effect of relatively reducing the size, the upper surface of the support base 76a is provided with a power steering device (not shown) and a suspension spring 83 provided on the base 76f (FIG. 7) before the lock mechanism is added. This is due to the inability to secure space for other parts already used.

[0006]

However, when the lock cylinder device 86 is locked, the lock cylinder device 86 receives an input load from the drive wheel 71 and the auxiliary wheel 73 when traveling on, for example, an uneven road surface. become. Further, the driving force of the driving wheels 71 is transmitted to the vehicle body frame via the drive unit 72, the parallel link mechanism 74, and the locking cylinder device 86, so that the locking cylinder device 86 serving as a driving force transmission path has a large force. Load will be applied. Therefore, the locking cylinder device 86
Is required to have rigidity and strength enough to withstand a large load, and it is necessary to use a relatively thick and heavy dedicated bracket 76d. Therefore, a large amount of material is used for the casting during the production of the support link 76, and a detailed inspection of the strength of the dedicated bracket 76d is required, so that the cost of parts is increased and the production cost of the suspension device is increased. It was also the cause.

On the other hand, a configuration in which the locking cylinder device 86 is directly attached to another link without forming the exclusive bracket 76d is also conventionally known. For example, Japanese Unexamined Patent Publication No.
In the technique of Japanese Patent Publication No. 00, the locking cylinder device is interposed between the lower link 77 and the vehicle body frame. In some cases, a locking cylinder device is interposed between the upper link 75 and the vehicle body frame. When the lock cylinder device is locked, the driving force of the drive wheels 71 is transmitted from the parallel link mechanism 74 to the vehicle body frame via the lock cylinder device. However, in these prior arts, the links between the links are connected because the driving force of the driving wheels 71 is transmitted from the support link 76 to another link and then transmitted to the vehicle body frame via the locking cylinder device. There is a problem that the vehicle body rattles even though the locking cylinder device is locked due to the backlash due to the structurally unavoidable gap between the connecting shaft and the insertion hole at the portion where the locking cylinder device is locked.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an industrial vehicle in which a drive unit having drive wheels and a driven unit having driven wheels are suspended from a vehicle body via a link mechanism. There is no need to extend a dedicated bracket for supporting the locking cylinder device on the link constituting the link mechanism, and it is possible to prevent rattling of the vehicle body when the locking cylinder device is locked. An object of the present invention is to provide a suspension lock device.

[0009]

According to a first aspect of the present invention, a drive unit having drive wheels and a driven unit having driven wheels are connected to a vehicle body frame via a link mechanism. A locking cylinder device for locking the link mechanism, wherein one of a plurality of links constituting the link mechanism and a vehicle body frame are provided. A suspension lock device for an industrial vehicle interposed therebetween, wherein the locking cylinder device is provided with two rotations of the support link for a support link supporting the drive unit among a plurality of links constituting the link mechanism. It is connected at the site sandwiched by the center of motion.

According to this configuration, when the locking cylinder device is locked, the driving force of the drive wheels is transmitted from the support link, which moves integrally with the drive unit, of the plurality of links constituting the link mechanism via the locking cylinder device. The transmission path of the driving force from the drive wheels to the vehicle body frame does not pass through the connection shaft of the links constituting the link mechanism, so that there is some structural backlash in the insertion part of the connection shaft. Even so, the body is locked securely. Further, since the locking cylinder device is connected to a portion sandwiched between the two rotation centers of the link, that is, a portion required for the support link to function as the link, a dedicated bracket for connecting the locking cylinder device is provided. Does not need to be extended to the support link.

According to a second aspect of the present invention, in the first aspect of the present invention, the support link has a support base on which a traveling motor constituting the drive unit is mounted, and the locking cylinder device is The traveling motor is connected to a position adjacent to the driven wheel with respect to the support base.

According to this configuration, the lock cylinder device is connected to the position adjacent to the driven wheel of the traveling motor with respect to the support base of the support link. The lock cylinder device is arranged by utilizing a space adjacent to the traveling motor.

According to a third aspect of the present invention, in the first or second aspect of the invention, the traveling motor and the locking cylinder device are provided at a position above the driving wheels in the vehicle width direction on the body of the industrial vehicle. A storage box in which is stored is erected, and a floor surface of a cab is formed at a position above the driven wheel.
An inner surface of a panel attached by a structure capable of opening the side facing the operator's cab of the housing box is arranged so as to face a component of the vehicle body frame and other housing components without being interposed therebetween.

According to this structure, the locking cylinder device accommodated together with the traveling motor and the like in the accommodation box provided upright at the position adjacent to the driving wheel side of the driver's cab in the vehicle width direction is provided with the operation room of the accommodation box. Since the panel that covers the facing portion and the other parts are positioned without interposition, the locking cylinder device can be maintained by opening or removing the panel. For this reason, maintenance work of the locking cylinder device becomes easy.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 5, a reach-type forklift truck 1 (hereinafter, referred to as a forklift) as an industrial vehicle is a three-wheeler type having two front wheels and one rear wheel. The left and right front wheels 2 are driven wheels, and one rear wheel is a driving wheel 3 also serving as a steering wheel. Drive wheel 3
The vehicle is offset to the left in the vehicle width direction, and an auxiliary wheel (caster wheel) 4 as a driven wheel that is paired with the drive wheel 3 on the left and right is provided on the right side thereof (see FIG. 1).

The forklift 1 has a mast 5 in front of a vehicle body (machine stand) 1a. The mast 5 is moved forward and backward along a pair of left and right reach legs 7 extending forward of the vehicle body 1a by driving the reach cylinder 6. The mast 5 includes an outer mast 8 and an inner mast 9. The inner mast 9 is moved up and down with respect to the outer mast 8 by driving the lift cylinder 10, so that the lift bracket 11 is moved up and down with a stroke approximately twice as large as that of the mast 5. Mounted fork 1
2 moves up and down. The fork 12 is tiltably attached to the lift bracket 11, and the fork 12 performs a tilting operation by driving a tilt cylinder (not shown).

A driver's cab 13 (see FIG. 1) of a standing type is provided on the rear right side of the vehicle body 1a, and a storage box 14 is provided on the left of the driver's cab 13. Storage box 14
The steering wheel 15 is provided on the upper surface of the steering wheel 15. Instrument panel 1 in front of cab 13
6 has an operation lever 17 for cargo handling operation and accelerator operation.
Is provided.

FIG. 1 and FIG. 2 show a rear suspension device with a locking function (rear suspension lock device) 20 mounted on the forklift 1. A drive unit 21 having a drive wheel 3 and a caster unit 22 as a driven unit having an auxiliary wheel 4 are provided at a rear portion of the vehicle body 1a.
Are suspended from the body frame 23 via a parallel link mechanism 24 as a link mechanism, so that the roll of the vehicle body 1a in the roll direction is allowed.

As shown in FIGS. 1 to 3, the parallel link mechanism 24 includes four upper links 25, support links 26, lower links 27, and caster links 28. FIG.
As shown in the figure, the links 25 to 28 are connected by four axes 29, 30, 31, 32 located at the vertices of the quadrilateral.

The right end of the upper link 25 is rotatably connected to the vehicle body frame 23 by a fixed shaft 29. The lower link 27 is rotatably connected to the body frame 23 by a fixed shaft 30 at a position near the center in the vehicle width direction. The support link 26 having an inverted L-shape in rear view as shown in FIG. 1 is connected to the left end of the upper link 25 at a central position in the vehicle width direction of the support base 26a by a shaft 31 so as to be relatively rotatable. The lower end of the arm 27b is connected to the left end of the arm 27 by a shaft 32 so as to be relatively rotatable.

As shown in FIG. 1, the caster link 28
The left end is rotatably connected to the fixed shaft 30, and the right end is inserted into a guide shaft 33 attached to the right end of the lower link 27, so that the left end is vertically opposed to the lower link 27. Displaceably connected. The set of two auxiliary wheels 4 is connected to the caster link 28 by a rotating mechanism 3.
5 (see FIG. 2) so as to be rotatable in a horizontal plane. A pair of caster springs 34 are interposed between the lower link 27 and the caster links 28 before and after the rotation mechanism 35 is sandwiched. The caster unit 22 includes the auxiliary wheel 4 and the rotation mechanism 35. Above the caster unit 22, a floor plate 13a of the cab 13 is arranged.

On the other hand, a drive motor 36 as a traveling motor is mounted on the upper surface of the support base 26a of the support link 26. A gear box 37 is attached to the lower part of the support base 26a so as to be rotatable in a horizontal plane, and the drive wheel 3 is rotatably supported by the lower part of the gear box 37. A gear wheel 38 fixed to an upper portion of the gear box 37 has a steering shaft 39 (shown in FIG. 2) that rotates in conjunction with operation of the steering wheel 15.
The drive wheel 3 is steered in accordance with the rotation operation of the steering wheel 15. The steering shaft 39 is inserted and connected to a power steering gear unit (PS gear unit) 41 to which a driving force of a power steering motor (PS motor) 40 is input.
The operating force of No. 5 is assisted (assisted) by the driving force of the PS motor 40.

As shown in FIGS. 1 and 2, the suspension spring 42 is mounted on a support plate 27a (shown in FIGS. 1 and 3) of the lower link 27, and its upper end extends from the body frame 23. It is arranged in a state where it is pressed and urged via the spring force adjusting mechanism 43 with respect to the bracket 23a to be pressed. The ratio at which the vehicle weight (rear wheel load) applied to the rear wheels is distributed to the driving wheels 3 and the auxiliary wheels 4 is determined by the link ratio of the parallel link mechanism 24 and the urging force of the suspension spring 42,
Each wheel pressure of the driving wheel 3 and the auxiliary wheel 4 is distributed at a suitable ratio according to the value of the rear wheel load. That is, the parallel link mechanism 24 rotates according to the rear wheel load that changes as the vehicle center of gravity moves back and forth due to the presence or absence of the load and the back and forth movement of the mast 5, and the wheel pressures of the drive wheel 3 and the auxiliary wheel 4 are reduced. Dispensed in a suitable ratio. For example, when the rear wheel load is relatively large in an unloaded state, the parallel link mechanism 24 takes a posture in which the auxiliary wheel 4 is rotationally displaced toward the side where the wheel pressure of the auxiliary wheel 4 is increased, and no excessive wheel pressure is applied to the drive wheel 3. Is adjusted as follows. When the rear wheel load is relatively small due to the reach of the mast 5 (moving forward to the mast position indicated by a chain line in FIG. 5) in a loaded state, the parallel link mechanism 24 increases the wheel pressure of the drive wheel 3. The required minimum wheel pressure is ensured for the drive wheel 3 by taking a posture that is rotationally displaced to the opposite side.

The locking cylinder device (hydraulic damper) 44 for locking the parallel link mechanism 24 is
3 and the support link 26. As shown in FIG. 3, a pedestal 26c for assembling the drive motor 36 on the upper surface of the support base 26a of the support link 26, a PS
26d for assembling the gear unit 41, a connecting bracket 26e for connecting the lower end of the rod 44a of the locking cylinder device 44, an insertion hole 26f of the shaft 31 for connecting to the upper link 25, and a lower link 27. 26g of the shaft 32 for connecting to the shaft 32. The connection bracket 26e is formed at a position closer to the auxiliary wheel 4 (right side) than the pedestal 26c and at the front side of the pedestal 26d.

The upper link 25 has an insertion hole 25a at a position facing the insertion hole 26f of the support link 26, and a hole 25c through which a shaft 29 connected to the vehicle body frame 23 is inserted by a cylinder 25b fixed to the right end. It is formed. The lower link 27 has an insertion hole 27b at a position facing the insertion hole 26g of the support link 26, and has an insertion hole 27c at a position facing the insertion hole 28a of the caster link 28.
The lower link 27 is provided with a support plate 27a near the left end and a base plate 27d near the right end. A seat (recess) 27e for mounting the suspension spring 42 is formed on the support plate 27a. A circular hole 27f is formed at the center of the base plate 27d to avoid interference with the rotating mechanism 35 of the caster unit 22. The caster link 28 has an assembly hole 28b into which the rotating mechanism 35 of the caster unit 22 is inserted, and the caster spring 3 is positioned before and after the assembly hole 28b.
A pair of seats (recesses) 28c for mounting the camera 4 is formed.

Locking cylinder device 44 and support link 2
6 is set at a position within a range between the two shafts 29 and 31 for rotating the support link 26. That is, the support link 26 is an essential part for functioning as a link, and is not a part additionally formed for connecting the locking cylinder device 44.

In particular, a support base portion of the support link 26 which is disposed substantially horizontally so that the lock cylinder device 44 does not need to be disposed sideways with its axial direction (longitudinal direction) oriented substantially horizontally. 26a is selected as the connection point. Further, the lower surface side of the support base portion 26a is a side where the arm portion 26b extends and it is difficult to take up space such as the presence of the gear wheel 38, whereas the upper surface side of the support base portion 26a is on the right side of the drive motor 36, Due to the bent shape of the arm 26b, a space equal to or greater than the thickness of the arm 26b is secured in the vehicle width direction.

Further, if the lower surface side of the support base 26a is selected as a connection point, it is necessary to extend the support base 26a rightward to secure a space, and accordingly, the upper link 25 also extends rightward. Driver's cab 1
3 becomes narrower in the vehicle width direction.

Further, a panel 45 is detachably attached to the accommodation box 14 at a position facing the operator's cab 13.
The maintenance inside is made possible. But,
When the lower surface side of the support base 26a is selected as a connection point, the arm 26
The position opposite to the operator's cab 13 is located at the position where the cylinder for locking is disposed, and the arm portion 26b hinders the cylinder maintenance work. For this reason, the upper surface side of the support base 26a is selected as a connecting portion of the locking cylinder device 44. Then, in order to facilitate maintenance work of the locking cylinder device 44 when the panel 45 is removed,
A layout is adopted in which the locking cylinder device 44 and the inner surface of the panel 45 are directly opposed to each other, and no intervening material such as a part of the vehicle body frame 23 or other housing components is disposed between the two. Of course, the connection location of the locking cylinder device 44 is not limited to the upper surface of the support base 26a, and the lower surface side of the support base 26a or the arm 26b may be selected as the connection location. In addition, the mounting structure of the panel 45 is not limited to a removable structure that can be detached, but may be any mounting structure that can open the inside of the storage box. For example, a structure of an opening / closing door system or a sliding system may be used.

In the prior art, the upper surface of the support base 26a is used for a space for disposing other components, and a suspension spring and a power steering device (PS gear unit) are disposed thereon. In the present embodiment, by disposing the suspension spring 42 on the upper surface of the support plate 27a formed on the lower link 27, a space for disposing the locking cylinder device 44 is secured on the upper surface of the support base 26a. The rod 44a of the locking cylinder device 44 is provided on the upper surface of the support base 26a at a position in front of the base 26d.
Is formed with a connecting bracket 26e for connecting the lower ends of the. In the state where the support link 26 is disposed on the body frame 23, the connecting bracket 26
A support bracket 46 for connecting and supporting the upper end of the cylinder body 44b of the locking cylinder device 44 is formed at a position directly above e. The locking cylinder device 44 is mounted on a support bracket 46 in which the upper end of the cylinder body 44b is fixed to the vehicle body frame 23.
The lower end of the rod 44a is connected to the connecting bracket 2 of the support link 26 (see FIG. 1).
6e so as to be rotatably connected and supported. The support base 26a of the locking cylinder device 44
The connection point in the vehicle width direction on the upper surface of the
It is located in the range between.

As shown in FIG. 4, the interior of the cylinder body 44b is divided into two chambers by a piston 44c, and two pipes 51 and 52 communicating with each of the two chambers are formed.
4b is connected. Opposite ends of the two pipelines 51 and 52 are connected to two ports of the electromagnetic switching valve 53, respectively. The electromagnetic switching valve 53 is opened and closed by controlling the solenoid 53 a to be deenergized by a controller 54. An accumulator 56 for storing hydraulic oil is connected to a pipe 55 connected to the pipe 51, and a check valve 57 for preventing backflow of the hydraulic oil to the accumulator 56 is provided on the pipe 55. I have. The electromagnetic switching valve 53 is shown in FIG.
When the valve is switched to the valve closing position shown in FIG. 7, the flow of hydraulic oil is disabled, and the locking cylinder device 44 is locked in a state where the rod 44a cannot be expanded or contracted. Further, when the electromagnetic switching valve 53 is switched to the valve opening position (the switching position opposite to the position in FIG. 4), the flow of the hydraulic oil is permitted, and the locking cylinder device 44 expands and contracts the rod 44a. Will be in an acceptable free state.

For example, the controller 54 is connected to an acceleration sensor 58 and a vehicle speed sensor 59 provided on the vehicle body 1a. When the tilting acceleration (lateral acceleration) detected by the acceleration sensor 58 exceeds a preset threshold value, the controller 54 switches the electromagnetic switching valve 53 to the valve closing position and switches the locking cylinder device 44, as in the prior art. Is to be locked. Further, the controller 54 locks the locking cylinder device 44 even when the vehicle speed detected by the vehicle speed sensor 59 is lower than the set value. This is when the fork 1
2 to raise the load and raise the height of the center of gravity of the vehicle to make the vehicle relatively unstable, so that the locking cylinder device 44 is locked during the cargo handling operation performed at a low speed or in a stopped state. This is to secure the stability of the vehicle body 1a. For this reason, the set vehicle speed is set to a value that allows a margin for the maximum vehicle speed during normal cargo handling work, for example, a value of about 5 km / h. The driving wheel 3
Lateral acceleration from a steering angle sensor that determines the steering angle (tire angle) θ of the vehicle and a steering angle θ (more specifically, a turning radius determined from the steering angle θ) and a vehicle speed V that can be determined from each detection value from a vehicle speed sensor 59 that detects the vehicle speed. Can be estimated by calculation.
Further, the height of the vehicle center of gravity at the time of loading a load is estimated based on each detection value from a lift sensor provided on the outer mast 8 and a load sensor including a pressure sensor for detecting the internal oil pressure of the lift cylinder 10, When the height of the center of gravity exceeds the threshold value, the locking cylinder device 44 may be locked.

For example, when the vehicle speed falls below the set value, the electromagnetic switching valve 53 is closed and the locking cylinder device 44 is locked. At this time, when the mast 5 loaded with the cargo for the cargo handling work reaches forward and the center of gravity of the vehicle moves forward, a force is lifted to the rear of the vehicle body 1a, but the locking cylinder device 44 is locked, and the Since the link mechanism 24 does not move, lifting of the rear portion of the vehicle body 1a is suppressed. Therefore, the vehicle body 1a during the cargo handling operation is stabilized.

The driving force of the driving wheels 3 is controlled by the drive unit 21.
From the support link 26 for supporting the lock cylinder device 4
4 and is transmitted to the vehicle body 1a without passing through the connecting shaft of the link of the parallel link mechanism 24,
Even if there is some backlash in the connection shaft portion of each link that is unavoidable due to the structure, the body 1a is locked when locked due to the backlash of the connection shaft.
No rattling phenomenon occurs.

As described in detail above, according to this embodiment,
The following effects can be obtained. (1) Since the locking cylinder device 44 is connected to the support link 26 at a portion sandwiched between the two shafts 31 and 32 that are the rotation centers thereof, the support link 26 is dedicated to cylinder support. There is no need to extend the bracket, and there is no connecting shaft of the parallel link mechanism 24 on the transmission path through which the input of the driving force from the driving wheels 3 and the like is transmitted to the vehicle body 1a via the locking cylinder device 44. Even if there is some backlash in the connection shaft of each link, it is possible to make it less likely that the vehicle body 1a will rattle due to the backlash during locking.

(2) Since the support link 26 is originally manufactured with high rigidity and strength, it can sufficiently cope with receiving a large load from the locking cylinder device 44 during locking. Therefore, the basic structure of the support link 26 can adopt the conventional structure as it is, and there is no need to change the design such as increasing the wall thickness. It is sufficient to change the design so that the connecting bracket 26e is additionally formed.

(3) The lock cylinder device 44 is connected to the upper surface of the support base 26a of the support link 26, which is disposed substantially horizontally, at a position adjacent to the drive motor 36 on the auxiliary wheel 4 side. Therefore, the lock cylinder device 44 can be arranged vertically, and there is no need to expand the storage box 14 in the vehicle width direction to secure a space for disposing the lock cylinder device 44. Therefore, the width of the cab 13 does not become narrow.

(4) The mounting position of the suspension spring 42 that urges the parallel link mechanism 24 is changed to the mounting position where the support plate 27a of the lower link 27 is pressed and urged from the upper surface, and locked to the upper surface of the support base 26a. A space for disposing the cylinder device 44 for the vehicle was secured. Therefore, the support base 26
The upper surface of “a” could be used as a connecting portion of the locking cylinder device 44.

(5) The locking cylinder device 44 is disposed on the upper surface of the support base 26a at a position adjacent to the auxiliary wheel 4 side of the drive motor 36, and faces the inner surface of the panel 45 with no other intervening members. When the panel 45 is removed and the inside is viewed, there is no obstacle in front of the locking cylinder device 44, and maintenance work of the locking cylinder device 44 is easy. In addition, suspension spring 4
Since there is no obstacle in front of the panel 2 when the panel 45 is removed, it is easy to adjust the urging force of the suspension spring 42.

It should be noted that the embodiment is not limited to the above-described embodiment, and can be implemented in the following modes. The connection point of the locking cylinder device 44 to the parallel link mechanism 24 is only required to be within a range sandwiched between the two rotation centers of the support link 26, and is not limited to the upper surface of the support base 26a. Absent. For example, the support base 26a
When the lower surface is selected as the connecting portion of the locking cylinder device 44, it is not necessary to extend the cylinder support dedicated bracket from the support link 26.

The suspension spring 42 may be attached so as to press the support link 26.
The structure of the link mechanism is not limited to that of the above embodiment. For example, the number of links constituting the parallel link mechanism and the shape of each link can be changed as appropriate. In short, a link mechanism in which the wheel pressures of the driving wheels and the auxiliary wheels are autonomously adjusted according to the rear wheel load is sufficient.

The locking cylinder device 44 may be disposed in an oblique position in which the axis is inclined with respect to the vertical line. For example, in FIG. 1, the upper end of the locking cylinder device 44 may be shifted rightward within a range until the upper end hits the inner surface of the panel 45 so that the axis is inclined at an angle of, for example, about 20 ° to 45 °.

The present invention is not limited to the reach type forklift. The present invention can also be applied to other industrial vehicles including a suspension device that is suspended on a vehicle body frame in a state in which a driving wheel and an auxiliary wheel are swingably connected by a link mechanism.

The technical ideas other than the claims that can be grasped from the embodiment and other examples will be described. (1) In claim 1, the connecting portion of the locking cylinder device to the support link is a support base on which the drive unit is mounted and arranged substantially horizontally. According to this configuration, the locking cylinder device can be arranged vertically, and the accommodation space in the vehicle width direction can be reduced.

(2) The support link according to any one of claims 1 to 3, wherein the support link has a substantially inverted L-shape when viewed from the rear, and a support base extending substantially horizontally and an arm extending substantially vertically when assembled. And the locking cylinder device is connected on the upper surface side of the support base. Since the installation space is secured on the upper surface side of the support base, it is not necessary to extend the support base long to secure the installation space of the locking cylinder device.

(3) In the technical idea of (1), wherein the link mechanism is a parallel link mechanism, and biases the parallel link mechanism to a side that increases the wheel pressure of the driving wheels. The biasing means (elastic member (suspension spring)) is disposed so as to be located on the auxiliary wheel side of the arm portion while pressing the upper surface of the lower link extending substantially horizontally and connected to the lower end of the arm portion of the support link. Have been. According to this configuration, the urging means (elastic member) is obtained by removing the panel.
Is easy to adjust the biasing force.

(4) The industrial vehicle according to any one of claims 1 to 3, wherein the industrial vehicle is a reach-type industrial vehicle in which a loading device moves back and forth with respect to the vehicle body, and the link mechanism is associated with the longitudinal movement of the vehicle center of gravity. Independently rotating so as to appropriately distribute the wheel pressures of the driving wheels and the driven wheels according to the load change.

[0048]

As described above in detail, according to the first to third aspects of the present invention, the locking cylinder device is provided between the two rotation centers with respect to the support link for supporting the driving wheels. It is not necessary to extend a dedicated bracket for connecting the locking cylinder device to the link, and it is also possible to prevent rattling of the vehicle body at the time of locking caused by play of the connecting shaft of the link mechanism. Can be.

According to the invention described in claim 3, according to claim 1
Alternatively, in addition to the effects of the second aspect of the present invention, the maintenance work of the locking cylinder device can be performed by removing the panel facing the cab of the storage box.

[Brief description of the drawings]

FIG. 1 is a rear view showing a rear suspension lock device according to an embodiment.

FIG. 2 is a plan view showing a rear suspension lock device.

FIG. 3 is an exploded perspective view of the parallel link mechanism.

FIG. 4 is a hydraulic circuit diagram of the rear suspension lock device.

FIG. 5 is a side view of the reach type forklift.

FIG. 6 is a rear view showing a conventional rear suspension device.

FIG. 7 is a perspective view of a link to which a conventional locking cylinder device is attached.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reach type forklift truck as an industrial vehicle, 1a ... Body, 3 ... Driving wheel, 4 ... Auxiliary wheel as a driven wheel, 13 ... Driver cab, 13a ... Floor plate, 14 ... Storage box, 20 ... Suspension lock device Rear suspension device with lock function, 21: drive unit, 22: caster unit as driven unit, 2
3 ... body frame, 24 ... parallel link mechanism as link mechanism, 25 ... upper link as link, 26 ... support link as link, 26a ... support base, 27 ... lower link as link, 28 ... as link Caster links 31, 32: shafts serving as rotation centers, 36: drive motors as traveling motors, 42: suspension springs, 44: locking cylinder devices, 45: panels.

Claims (3)

[Claims] A drive unit having a drive wheel and a driven unit having a driven wheel have a suspension suspended in a state of allowing the body frame to swing in a roll direction with respect to a body frame via a link mechanism, wherein the link is provided. A lock cylinder device for locking a mechanism is an industrial vehicle suspension lock device interposed between one of a plurality of links constituting the link mechanism and a vehicle body frame, wherein the lock cylinder is A suspension lock device for an industrial vehicle, wherein the device is connected to a support link supporting the drive unit among a plurality of links constituting the link mechanism at a portion sandwiched between two rotation centers of the support link. 2. The support link has a support base on which a drive motor constituting the drive unit is mounted, and the locking cylinder device is positioned adjacent to the support base on the driven wheel side of the drive motor. The suspension lock device for an industrial vehicle according to claim 1, wherein the suspension lock device is connected to the suspension lock device. 3. A housing box for housing the traveling motor and the locking cylinder device is provided upright at a position above the drive wheels in a vehicle width direction on a body of the industrial vehicle, and is provided above the driven wheels. A floor surface of an operator's cab is formed at a position, and the lock cylinder device includes an inner surface of a panel attached by a structure capable of opening a side of the storage box facing the operator's cab, and a body frame structure. The suspension lock device for an industrial vehicle according to claim 1, wherein the suspension lock device is disposed in a state in which the portion and another housing component are opposed to each other without any interposition.