JPS60124512A - Suspension system for fork-lift truck - Google Patents

Abstract

PURPOSE:To prevent a carbody from its excessive inclination to both directions, by installing a pair of center pins projectingly from the central part of a rear axle beam to the front and the rear, while making a body frame support them free of rotation, and installing a damper device inclusive of rubber in a tip part of each pin. CONSTITUTION:A pair of center pins 14 are projected in a longitudinal direction concentrically with each other and locked to the central part of a rear axle beam 10 to be attached to rear wheels 12 at both ends, while each pin 14 is rotatably supported on a bearing part 16 connectdly installed in the lower part of a body frame. Then, a cross-shaped cam 18 having four projections 22 is solidly installed in the tip part projected outward from the bearing part 16 of each pin 14, making a damper device 20 locked to the bearing part 16 engage each cam 18, and the body frame is made possible to be energized in a neutral attitude direction. The damper device 20 is made up of bonding and locking a quarter round0form rubber member 26, capable of partitioning a cross-shaped space, to the inside of a square box-form outer case 24.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a suspension system for forklifts ranked 1 to 1, and particularly relates to a suspension system that has an excellent ability to prevent the vehicle body from overturning when lifting a load at high altitude. .

BACKGROUND ART One type of suspension system for a conventional forklift trunk (hereinafter simply referred to as a forklift) is one in which a rear axle beam to which a rear wheel is attached is rotatably supported by a vehicle body frame via a center pin. In this case, the vehicle body is supported at three points: this center pin and the two front wheels, so a stopper is provided between the vehicle body and the rear axle beam to regulate the tilt angle of the vehicle body, preventing the vehicle from tipping over. Usually, this is done. However, with conventional suspension systems that simply restrict the maximum tilt angle of the vehicle body with respect to the rear axle beam by providing a stopper, when the center of gravity moves to a high position such as when unloading a load, the vehicle body tilts significantly. cannot be prevented from doing so.

On the other hand, as a means to avoid such drawbacks, a damper device having a predetermined elastic coefficient is interposed between the vehicle body and the axle beam, so that when the vehicle body is tilted with respect to the rear axle beam, the direction of the tilt is It is conceivable to apply a returning force in the opposite direction in proportion to the inclination angle. However, in this case, if the elastic modulus of the damper device is increased with emphasis on the function of preventing the vehicle body from tilting at a large angle,
When the vehicle body is not inclined to the rear axle beam that much, rotation of the rear axle beam relative to the vehicle body is obstructed, and the function to prevent the vehicle body from shaking due to uneven road surfaces is impaired, and on the contrary, the anti-swaying function is improved. If the elastic modulus of the damper device is made small in an attempt to achieve this, the function to prevent the vehicle body from tilting significantly with respect to the rear axle beam will be insufficient.

Purpose of the Invention The present invention has been made in view of the above circumstances, and its object is to provide a pair of center pins concentrically protruding forward and backward from the center of the rear axle beam. is a type of suspension system that is rotatably supported by the body frame of a forklift truck, and allows the vehicle body to tilt significantly relative to the rear axle beam without impairing the vehicle body's ability to prevent rocking as much as possible during driving. It is an object of the present invention to provide a suspension device that can adequately perform the function of preventing this.

Arrangement of the Invention To achieve this object, the present invention provides 1'I! , the suspension device as described above includes a cam provided integrally with at least one of the pair of center pins and having at least one protrusion extending outward in the radial direction of the center pin; (bl) has an outer case fixed to the vehicle body frame and two rubber parts located inside the outer case so as to be located on both sides of the protrusion in the circumferential direction of the center pin; a first damper device in which one of the two rubber members is in contact with one side of the protrusion while the other is spaced a certain distance from the other side of the protrusion; It has a similar structure, and is fixed to the vehicle body frame with a different relative phase with the first damper device or with the front and back reversed, and when the rear axle beam is in the neutral state, one of the two comb members is fixed to the vehicle body frame. a second damper device that is in contact with the other side surface of the protrusion of the cam or a side surface on the same side as that of the protrusion of another cam, while the other side is separated from the opposite side surface by a fixed ratio 1i11; configured.

Effects of the Invention With this method, when the angle of inclination that appears on the rear axle beam of the vehicle body increases, such as when cargo is lifted high, a large return force is applied to the vehicle body frame in the opposite direction to the direction of inclination. This makes it possible to prevent the vehicle body from tilting at a large angle, making cargo handling work easier, and also effectively preventing the vehicle body from overturning. In addition, during normal driving with a small angle of inclination of the vehicle body, by keeping the return force small, the return force does not impede the rotation of the vehicle body and rear axle beam. It is possible to effectively prevent the rocking of the

Moreover, in the present invention, since the two damper devices have the same structure, there is an advantage that the design, manufacturing and management costs of these damper devices and, by extension, the manufacturing cost of the suspension system can be reduced.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1 and 2 show forklift l-
4U is a diagram showing the main parts of an embodiment of the racking device, and in these figures, 10 is a rear axle beam,
A rear wheel 12 is attached to both end portions, and a pair of center pins 14 are fixed to the center portion of the rear wheel 12 so as to protrude concentrically from each other in the front-rear direction. Reference numeral 16 denotes a bearing portion extending downward from the body frame of the forklift, and is provided to sandwich the rear axle beam 10 from the front and back, and the center bin 14 of the rear axle beam 10 is rotated by the bearing portions 16. Possibly supported. In other words, Riet axle beam 10
is rotatably supported by the vehicle body frame around a center pin 14.

The tip portions of the center pin 14 of the rear axle beam 10 are made to project forward and rearward from the bearing portion 16, respectively, and cams 18 of the same shape are each integrally provided on these protruding tip portions. Further, damper devices 20 having the same shape as first and second damper devices are respectively fixed to the bearing portion 16 in a state where they are engaged with the cams 18. The bearing portion 16, that is, the vehicle body frame is normally held at a neutral position with respect to the rear axle beam 10. Note that the neutral position herein refers to a relative position when the vehicle body frame is in a neutral state in which it is not inclined to the left or right with respect to the rear axle beam 10.

In this embodiment, the vehicle body has a rear axle beam 10.
When the vehicle body is tilted relative to the neutral position and the tilt angle from the neutral position is smaller than the predetermined angle α, the return force that biases the vehicle body toward the neutral position is small relative to the tilt angle, and when the tilt angle is greater than or equal to α. When the angle of inclination reaches
The rotation of the rear axle beam 10 is maintained in a good condition, and the vibration of the rear axle beam 10 caused by irregular road surfaces is effectively prevented from being transmitted to the vehicle body. When the vehicle attempts to tilt significantly, a large return force acts to return the vehicle to the neutral position, effectively preventing the vehicle from tilting at a large angle.

That is, the cam 18, as shown in FIG.
4111 radially outward from the center pin 14, respectively.
The protrusions 22 of a are extended with a phase difference of 90'' to form a cross shape, and the cams 18 are provided in the same phase in the circumferential direction of the center pin 14 without forming a cross shape. , while damper device 2
As shown in FIG. 4, rubber members 2G each having an approximately quarter-circular cross section are fixedly disposed by adhesive at each corner of an outer case 24 having a square box shape. A space capable of accommodating the cam 18 is formed between the rubber members 26, and the outer case 24 is welded, bolted, etc. to the bearing portion 16 with the cam 18 accommodated in the space. It is fixed by appropriate means. In this embodiment, when the vehicle body frame is in a neutral position with respect to the rear axle beam IO, both damper devices 20 are moved around the center pin 14, as shown in FIGS. As shown in FIG. Each rubber member 26 contacts the right side surface 28 of the projection 22 in the circumferential direction of the center bin 14, and the left side surface 30 and each rubber member 26
The damper device 20 on the rear side of the vehicle body is separated by a predetermined distance from the , the left side surface 30 of each protrusion 22 of the cam 18
Each rubber member 26 is in contact with the right side surface 28 and the rubber member 26
There is a certain gap between them.

As shown in Fig. 1-C, stoppers 27 are provided at both ends of the lower part of the vehicle body frame to prevent the vehicle body from tilting more than a certain angle relative to the rear axle beam IO. ing.

In such a suspension system, when the vehicle body frame is in a neutral position with respect to the rear axle beam 10, the cam 18 merely contacts both damper devices 2o and does not receive any force from either of them. However, if the vehicle body frame is tilted rightward with respect to the rear axle beam 10 from its neutral position, each damper device 2o is rotated in the direction d1 relative to each cam 18 from the neutral position in FIG. In the damper device 2o on the +iiij side, as shown in FIG.
As shown in a), each rubber member 26 is separated from each protrusion 22 of the cam 18, and in the damper device 2o on the rear side of the vehicle body, each rubber member 26 is separated from each protrusion 22 of the cam 18, as shown in FIG. As a result, the damper device 20 on the rear side is forced onto the vehicle body frame in the opposite direction to the inclination direction.
A returning force based on the deformation of each rubber member 26 acts. Then, when the vehicle body frame tilts further to the right and the tilt angle from the neutral position exceeds α, as is clear from FIGS. As a result of being pushed and deformed by the cam 18, both damper devices 2 are attached to the vehicle body frame.
A returning force based on the deformation of each rubber member 26 of 0 is applied. Rear axle beam 10 of the above body frame
The relationship between the tilt angle and the return force acting on the vehicle body frame is the same even when the vehicle body is tilted leftward from the neutral position.

In the suspension system of this embodiment, as shown by the solid line in FIG. The force trying to return it suddenly increases,
This effectively suppresses the inclination of the vehicle body with respect to the rear axle beam 10, making cargo handling operations easier and effectively preventing the vehicle body from overturning. During normal driving, when the damper device 20 is small, only one of the damper devices 20 exerts a return force on the vehicle body, and the return force is kept small. is appropriately controlled, and therefore, even when driving on rough roads, shaking of the vehicle body can be effectively avoided. In addition, the 8th
In the figure, the broken line and the dashed-dotted line indicate the relationship between the return force applied to the vehicle body based on the deformation of each rubber member 26 of the damper device 20 at the front and rear of the vehicle body and the inclination angle of the vehicle body, respectively.

Although one embodiment of the present invention has been described above, this is literally an illustration, and the present invention should not be interpreted as being limited to the above embodiment.

For example, in the embodiment described above, when the vehicle body is in a neutral position with respect to the rear axle beam 10, each rubber member 26 of both tamper devices 20 simply contacts each protrusion 22 of the cam 18, and the cam 1B Although the explanation has been made on the assumption that no force is applied from the damper devices 20, each of the rubber parts +A26 of both damper devices 20 is brought into contact with each protrusion 22 of the cam 18 with the same amount of deformation in advance. It is also good. In this case, the eighth
The relationships between the return force and the inclination angle shown by solid lines, broken lines, and dashed-dotted lines in the drawings are as shown by the corresponding lines in FIG. 9, respectively.

Further, in the embodiment, each rubber member 2 of the damper device 20
6 were explained as being made of materials with the same elastic modulus, but for example, as shown in FIGS. 10(a) and (bl),
The rubber member 26 is the first rubber on the side that contacts each protrusion 22 of the cam 18! 40 and a second rubber layer 42 on the side opposite to each protrusion 22 at a certain distance. In this way, the rubber JLi0.42 of those two layers
By appropriately setting the elastic modulus of
It becomes possible to independently set the relationship between the return force and the inclination angle in the case where the force is smaller and when the force is larger. Note that the angle α can of course be set as appropriate depending on the situation, and each rubber part side has a multilayer structure.
It is also possible to change the relationship between the return force and the inclination angle more smoothly.

Further, in the embodiment described above, the front and rear cams 18 were made to have the same phase, and the damper device 20 was fixed with a phase difference α, but conversely, the front and rear damper devices 20 were made to have the same phase, and the cam 18 The effects of the present invention can be achieved even if the phase difference α is given to the phase difference α.

Further, in the above embodiment, the cam 18 was provided with four protrusions 22, and the damper device 20 was provided with four rubber members 26, but the cam and damper device do not necessarily have four protrusions 22. +1 lil protrusion and rubber part 10A
It is not necessary to have For example, as shown in FIG. Four cams are provided point-symmetrically around the axis of the center pin 14, and when the rear axle beam 10 is in a neutral state, the cam 18 on the front side of the vehicle body
A rubber member 26 located at a position facing the right side surface 28 of each protrusion 22 and the left side surface 30 thereof on the rear side of the vehicle body, respectively.
While touching each protrusion 22 of the cam 18 on the front side of the vehicle body.
The left side surface 30 of the vehicle body and the right side surface 28 thereof on the rear side of the vehicle body may be spaced a certain distance from the rubber member 26 located at the opposing position. In addition, the above-mentioned cam 18 and knocking device 20 are shown in the same figure (al, (bl).
The object of the present invention can also be achieved with a configuration of only the right half or left half of each. In addition, when the rubber member that contacts each protrusion of the cam and the rubber member that faces each protrusion of the cam at a certain distance from each protrusion of the cam are made into separate rubber members in this way, when the rear axle beam is in the neutral state, Since their elastic modulus can be set independently, it is possible to obtain the same effect as when the rubber layer is made of two layers fjh.

In addition, in the above embodiments, the
Damper devices 20 are provided at the front and back of the vehicle body with the rear axle beam 10 in between. They may be provided one over the other in the center direction.In this case, if the cams have the same phase, the two
The center pin 1 of the cam 18 is
4 can be replaced with one long cam in the axial direction, and the cost of installing the cam can be reduced. In addition, the fifth
In the case where a damper device having different phases as shown in FIGS. With one damper device that is long in the axial direction G of the center pin 14, it becomes possible to rotate the first and second damper devices, and there is an advantage that the damper device can be installed at a low cost.

In addition, it goes without saying that the present invention can be practiced with various modifications, improvements, etc. without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention with the body of a forklift truck 1 to the trunk removed, and FIG. 2 is a schematic view of FIG. Fig. 3 and Fig. 4 are cross-sectional views of the center pin perpendicular to the axis of the center pin for explaining the cam and the first and second damper devices shown in Figs. FIG. 5 is a diagram showing the relationship between the cam and the damper device in the neutral state of the rear axle beam of the embodiment shown in FIG. 1, and FIG. No. 5, which shows a state tilted to the right.
FIG. 7 is a diagram corresponding to FIG. 5 showing a state in which the vehicle body is tilted to the right even more than the state shown in FIG. 6, and FIG. 8 is a diagram corresponding to FIG. It is a graph showing the relationship between the inclination angle from the position and the return force acting on the vehicle body. FIG. 9 is a diagram corresponding to FIG. 8 in another embodiment of the present invention, and FIGS. 10 and 11 are diagrams corresponding to FIG. 5 showing still another embodiment. 10: Rear axle beam 14: Center pin 16: Bearing part of the vehicle body frame 18: Cam 20: Damper device (first, second) 22: Protrusion 24: Outer case 26: Rubber side 28 = Right side 30: Left side 40 :First rubber layer 42:Second rubber layer Applicant Toyota Industries Corporation Figure 8 Figure 9! , 4

Claims (1)

[Claims] A suspension system in which a pair of center pins concentrically protrude forward and backward from the center of a rear axle beam are rotatably supported by a body frame of a forklift 1 to I- rank. a cam provided integrally with at least one of the pair of center pins and having at least one protrusion extending outward in the radial direction of the center pin; an outer case fixed to the vehicle body frame; has two rubber members disposed on the inner side of the center pin so as to be located on both sides of the protrusion in the circumferential direction of the center pin, and when the rear axle beam is in a neutral state, one of the two rubber members is attached to the protrusion. a first damper device that contacts one side of the protrusion while the other is spaced a certain distance from the other side of the protrusion; and a first damper device that has a similar structure to the first damper device and has a relative phase with the first damper device. When the rear axle beam is in a neutral state, one of the rubber members is attached to the other side of the protrusion of the cam or the protrusion of another cam. 1u of a forklift truck, characterized in that it includes a second damper device that is in contact with the side surface on the same side as the second damper device, while the other is in a state where it is in a state where it is in a state where it is in a state where the other side is in contact with the side surface on the opposite side by a certain distance!1illPJl
Elevating equipment.