JPH0581441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a caster capable of actively changing direction, which is effective in forklifts, automatic guided vehicles, large mobile robots, and the like.

[Prior Art] The present inventor has previously proposed a caster capable of actively changing direction (Japanese Patent Laid-Open No. 60-252003).

As shown in FIG. 9, this previously proposed caster has a wheel support b supported by a rotary shaft c so as to be rotatable around a vertical axis on a machine body a, and a pair of wheels attached to the wheel support b. A horizontal wheel shaft e having wheels d rotatably attached to both ends thereof is supported so as to be movable in parallel to three positions in the horizontal direction by a pseudo-linear link mechanism constituting a wheel position control device f.

The pseudo-linear link mechanism described above has links g and h rotatably attached to a wheel support b, and the end and intermediate position of a third link i rotatably attached to the tips of these links g and h. A horizontal wheel shaft e is supported at the tip of the third link i, and in the illustrated wheel position control device f, this link mechanism is arranged symmetrically on both sides of the horizontal wheel shaft e. . This link mechanism is capable of imparting parallel movement in the horizontal direction to the horizontal wheel axis e at the tip of the third link i by providing a required dimensional relationship to each link. In addition, this link mechanism has a mechanism that drives the horizontal wheel axis e to rotate the rotation axis c.
A driving device j is connected to the drive device j for shifting the rotation position to three positions: a rotation position directly below the rotation position, and a pair of driven rotation positions that are translated in parallel on both sides of the rotation position.

Furthermore, the wheel support b is rotatably supported by a rotating shaft c, and is connected to a motor m via a clutch k in order to drive the rotating shaft c.

This caster is particularly effective when the vehicle body is to be rotated by a large angle close to a right angle at a stopping position.In such a case, the clutch k connects the motor m and the rotating shaft c. However, when the horizontal wheel shaft e is held at the central turning position by the drive device j and the motor m is rotated, the friction between the wheel d and the ground contact surface becomes minimal, so even when the vehicle body is stopped, The direction of the wheel d can be changed without resistance, and since the wheel d turns around the vertical axis around which the wheel support b rotates, the attitude of the vehicle body is not affected. In addition, with the horizontal wheel shaft e held in the driven rotation position, the clutch k is
If the connection between the motor m and the rotating shaft e is cut off, the caster can be used as having the same function as a normal caster.

However, in such a caster, a drive device j for horizontally translating the horizontal wheel shaft e is connected to a wheel support body b that rotates with respect to the machine body a.
Therefore, it is necessary to supply electric power and fluid pressure from the aircraft body a side to the drive device j on the wheel support body b side, and the power supply means such as power lines and pressure fluid piping for this purpose are connected to the wheel support body. It is necessary to make the body b rotate many times in any direction without causing any trouble, and even if the body b is passed through the rotation axis c of the wheel support b, this is likely to cause a malfunction.

[Problems to be Solved by the Invention] A technical problem to be solved by the present invention is that in the above-mentioned active direction changeable caster, the driving device (actuator) for horizontally translating the horizontal wheel shaft is connected to the wheel. It is installed on the machine body side that supports the support body, and allows stable parallel movement of the horizontal wheel shaft in the horizontal direction with a simple structure without supplying power or fluid pressure from the machine body side to the wheel support body side. It's about doing.

[Means for Solving the Problems] To achieve the above-mentioned problems, the active direction changeable caster of the present invention has a rotary shaft supporting a wheel support on a machine body so as to be rotatable around a vertical axis,
A horizontal wheel axle that rotatably supports a wheel at both ends is supported on the wheel support body so as to be movable in parallel in the horizontal direction by a link mechanism, and the horizontal wheel axle is
The rotary shaft of the wheel support is movable between a rotating position directly below the rotating shaft and a pair of driven rotating positions parallel to both sides from the rotating position, and the rotating shaft of the wheel support is connected to a rotary drive device on the fuselage via a clutch. A wheel shaft forced dislocation in which a sliding rod is slidably inserted into the rotating shaft of the wheel support, and the sliding rod acts on the link mechanism to move and hold the horizontal wheel shaft at the turning position. It is constructed by providing a mechanism and an actuator for driving the sliding rod in the axial direction on the body side.

[Function] The above-mentioned caster allows the wheels to change direction without resistance while the vehicle body is stopped when the vehicle body to which it is attached makes a large angle turn near a right angle at a certain stop position. When changing the direction of the wheels, first, the actuator on the fuselage operates the sliding rod, and the forced wheel axle displacement mechanism moves and holds the horizontal wheel axle to a turning position directly below the rotation axis of the wheel support. Furthermore, the wheel support clutch is connected to a rotary drive device such as a motor, and in this state the wheel support is rotated so that the wheels face the desired direction of travel.

In this case, since the friction between the wheels and the ground surface is minimal, the wheel support can smoothly rotate around the rotating shaft without resistance.
Moreover, since the wheels rotate around the rotation axis, the attitude of the vehicle body is not affected.

To run the vehicle from this state, the horizontal wheel axle is freed by returning the sliding rod,
In addition, all that is required is to release the connection between the wheel support and the rotary drive device that turns it using the clutch, and then move the vehicle in the desired direction. It will naturally move to the driven rotation position.

When the horizontal wheel axle is thus moved to the driven rotation position, it can be used in exactly the same way as a normal caster.

In addition, when the vehicle starts moving in the opposite direction to the direction in which it was traveling earlier, the horizontal wheel axle will naturally flow in the opposite direction as the vehicle moves forward, and after that, it will behave like a normal caster. It can be used for.

[Embodiment] FIG. 1 shows an embodiment of the present invention. In this caster, the machine body 1 is equipped with a wheel support 6 on which a rotating shaft 7 is rotatably supported via bearings 3 and 4. There is. This wheel support 6 has a horizontal wheel axle 8 on which a pair of wheels 9, 9 are rotatably attached at both ends.
The horizontal wheel shaft 8 is slidably supported by a pair of horizontal elongated holes 10 provided in the opposing walls of the wheel support 6, and is also supported by a support link of the pseudo-linear drive link mechanism 11. 12a, 12b
It is rotatably supported by the connecting part of.

This link mechanism 11 has links 13a and 14a rotatably attached to one side of the wheel support 6, and the ends and intermediate positions of the support link 12a are rotatably attached to the tips of these links 13a and 14a. Link 1 with a similar configuration to these
2b, 13b, and 14b are provided symmetrically, and the horizontal wheel axle 8 is supported by the connecting portion at the tip of the support links 12a, 12b. By giving the dimensional relationship, the support link 12
a, 12b, that is, the horizontal wheel axle 8 supporting the wheel 9, is moved horizontally, and the horizontal wheel axle 8 is moved to a turning position directly below the rotating shaft 7 by the wheel axle forced displacement mechanism 18, which will be explained below. and a pair of driven rotational positions that are translated from the rotational position to both sides in the horizontal direction.

For driving the link mechanism 11, the wheel support 6
A wheel shaft forced displacement mechanism 18 is used which is operated by a sliding rod 17 that slides within the rotating shaft 7 of the vehicle. This forced displacement mechanism 18 has a pair of rollers 20a, 20b rotatably attached to the lower end of the sliding rod 17, and these rollers 20a, 20b are operated by the urging force of a spring 22 interposed between the rollers 20a, 20b and a spring seat 21. By pressing down against the
Tapered contact portion 2 in either a or 14b
3a, 23b, and further the spring seat 21
By pressing and raising the tilted link 14a (or 14b) using the horizontal wheel shaft 8 as a stopper, the horizontal wheel shaft 8 is moved to a turning position directly below the rotating shaft 7, and is held at that position. Furthermore, when the sliding rod 17 is held in an elevated state, the link mechanism 11 becomes free, so that
The horizontal wheel axle 8 moves in the direction opposite to the traveling direction of the vehicle body, and the link 14a or 14b abuts the spring seat 21 as a stopper, so that the horizontal wheel axle 8 is moved in parallel in the horizontal direction from the above-mentioned turning position. It is transferred and held in the rotational position.

The sliding rod 17 is fitted by a spline 24 so that it slides axially but not rotates within the rotating shaft 7 of the wheel support 6; An axial driving force is transmitted to a driving body 26 in an actuator 25 such as a solenoid that is driven in the axial direction, but the actuator 26 is connected so as to be freely rotatable.

Moreover, the rotation shaft 7 of the wheel support body 6 mentioned above includes
A rotation transmission mechanism such as a gear 27 is provided at the upper end thereof, and is connected to a motor or other rotation drive device 29 via a clutch 28.

Therefore, the clutch 28 causes the rotary drive 29
is connected to the rotating shaft 7 , the horizontal wheel shaft 8 is held at a turning position directly under the rotating shaft 7 by the wheel shaft forced displacement mechanism 18 , and the wheel support 6 is moved in place via the rotating shaft 7 by the rotary drive device 29 . When the wheels 9 are rotated so as to face the direction in which the vehicle is moving, the friction between the wheels 9 and the ground contact surface is minimized, so even when the vehicle is stopped, the wheels 9 can be easily rotated without resistance, even in a large angle range of right angles. can be changed. Moreover, the rotating shaft 7
Since the wheels 9 turn around , the turning of the wheels does not affect the attitude of the vehicle body. Also,
By demagnetizing the actuator 25 and pushing up the sliding rod 17 with the spring 22, the horizontal wheel shaft 8 is freed, and the connection between the rotary drive device 29 and the rotary shaft 7 by the clutch 28 is severed. If the horizontal movement of the wheel 9 is free, the horizontal wheel shaft 8 is transferred and held at the driven rotation position in the direction opposite to the direction of movement of the vehicle body, as described above.
It can be used as having the same function as a normal caster. Furthermore, like this, the wheel 9
When the horizontal movement of is free,
When the vehicle body starts moving in the opposite direction to the direction in which it was previously traveling, the horizontal wheel axle 8 naturally flows in the opposite direction to the new direction as the vehicle body advances, and then the horizontal wheel axle 8 It is transferred and held in the other driven rotation position and used in the same way as a normal caster.

As described above, the actuator 25 that slides the sliding rod 17 of the wheel axle forced displacement mechanism 18 in the axial direction is provided on the side of the machine body 1 that rotatably supports the rotating shaft 7, thereby moving the horizontal wheel axle 8. When the actuator is transposed, the structure of the wheel support 6 can be simplified as compared to the case where the actuator is provided on the wheel support 6, and various considerations regarding power transmission means to the actuator are unnecessary.

FIGS. 2 and 3 are for explaining such an operating state. In FIG. 2, the wheel 9 is held at the center turning position and the wheel support 6 is placed at the solid line position around the rotating shaft 7. Fig. 3 shows a state in which the wheel 9 is rotated from the position shown in dotted lines to a position shown in dotted lines, and a state in which the wheel 9 is kept at one driven rotation position and used in the same way as a normal caster.

FIGS. 4 and 5 show another embodiment of the present invention. In this embodiment, as in the previous embodiment, a wheel support 36 is rotatably attached to the fuselage.
The left and right ends of the bearing frame 43 are rotatably supported by the two right and left support links 42a and 42b that constitute the link mechanism 41, thereby making the bearing frame 4
3 is mounted so as to be swingable in a substantially horizontal direction, and this bearing frame 43 supports a horizontal wheel shaft 38 with wheels 39 rotatably mounted on both ends, and the support links 42a,
A pair of pins 46a, 46b rotatably connecting the bearing frame 42b and the bearing frame 43 are slidably inserted into long holes 45a, 45b of a pair of drive links 44a, 44b constituting a wheel shaft forced displacement mechanism. The drive links 44a and 44b are rotatably attached by pins 48 to the lower ends of a sliding rod 47 which is slidable within the rotating shaft 37 of the wheel support 36.

The pair of support links 42a, 42b may or may not be parallel, but if they are parallel, the horizontal wheel axle 38 has a radius equal to the length of the support links 42a, 42b, similar to the pins 46a, 46b. It moves on a convex circular arc locus, and if it is not parallel, it draws a substantially horizontal locus determined according to the length of each support link, the distance between the pins 46a, 46b, etc.
Although it is desirable that these trajectories be as horizontal as possible, it is easier to move the horizontal wheel axle 38 to the central turning position if they are formed into a slightly upwardly convex arc shape.

Note that the other configurations and operations are the same as those of the embodiment shown in FIG.

FIG. 6 shows still another embodiment of the present invention, in which a horizontal wheel shaft 58 on which a wheel 59 is attached is inserted into a horizontal elongated hole provided in the opposite wall of a wheel support 56 that rotates around a rotation axis 57. 60 and whose horizontal wheel axle 58 is tiltably attached to the wheel support 56 by a pin 65;
It is inserted into the elongated hole 64 of. This drive link 63
constitutes a link mechanism for horizontally moving the horizontal wheel shaft 58 in parallel, and its drive link 63 is attached to the lower end of a sliding rod 67 that slides within the vertical shaft 57 of the wheel support 56. When the sliding rod 67 is pulled upward by an actuator (not shown), the drive link 63 is erected and the horizontal wheel axle 58 is moved to the central turning position. It is configured to be transposed.

This state is maintained immovably by the cylindrical holder 69, which is lowered by another actuator, fitting into the tapered portion 70 of the drive link 63 in the upright state.

In order to return the wheel 59 to the driven rotation position, it is sufficient to release the holding of the drive link 63 by the cylindrical holder 69 and at the same time release the traction of the sliding rod 67.If this state is maintained, the caster When the vehicle travels in a driven manner, the horizontal wheel shaft 58 moves in the direction opposite to the traveling direction within the long hole 60 of the wheel support 56, and shifts to the driven rotation position.

Furthermore, by making the upper guide surface of the long hole 60 into an upwardly convex arc shape as shown by the chain line, or by providing a concave portion in the center of the guide surface, the movement of the horizontal wheel shaft 58 to the center is facilitated. Furthermore, it becomes possible to hold the horizontal wheel axle 58 at the central turning position without providing the cylindrical holding body 69 and the actuator for driving it.

Furthermore, the horizontal wheel axle 58 is
It is also possible to eliminate the sliding part by supporting it with a link mechanism as shown in FIG. It can function in the same way as an arcuate guide surface.

7 and 8, two connecting links 88a and 88b are used in place of the cylindrical holder 69 and the actuator that drives it in the embodiment shown in FIG. A configuration that can be held in a rotating position is illustrated.
That is, in the embodiment of FIG.
Instead of the configuration in which the drive link 83 is fitted into the tapered portion 70 of the drive link 63, two connecting links 88a and 88b are connected to the driving link 83 with a pin 89, and the length of the tips of these connecting links 88a and 88b is A pair of pins 91a, 91b are fitted into the holes 90a, 90b and spaced apart from each other at the lower end of a sliding rod 87 that slides within the rotating shaft of the wheel support.

Therefore, when the sliding rod 87 is moved upward as shown in FIG. 8, the drive link 83 is erected by both connecting links 88a and 88b, and the horizontal wheel axle 78 is moved to the central turning position. can be held. Further, when the upward movement of the sliding rod 87 by the actuator is released, the drive link 83 is tilted and the horizontal wheel shaft 78 becomes movable to the driven rotation position, as shown in FIG.

[Effects of the Invention] According to the caster of the present invention described in detail above, like the previously proposed caster described above, the actuator for translating the horizontal wheel shaft in the horizontal direction and displacing it to the turning position is mounted on the wheel support. Since it is not provided on the body side, but is provided on the machine body side that supports the wheel support body, there is no need to supply power or fluid pressure from the machine body side to the wheel support body side, and the above horizontal wheels can be stably mounted with a simple structure. A parallel movement of the axis in the horizontal direction can be performed.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an active direction changeable caster according to the present invention, FIGS. 2 and 3 are illustrations of its operation, and FIGS. 4 and 5 are sectional views of other embodiments.
FIG. 6 is a sectional view of yet another embodiment, FIGS. 7 and 8 are side views of essential parts showing different operating states of the other embodiments, and FIG. 9 is a configuration diagram of an already proposed caster. 1... airframe, 6, 36, 56... wheel support,
7, 37, 57...Rotating axis, 8, 38, 58, 7
8... Horizontal wheel axle, 9, 39, 59... Wheel, 1
1... Link mechanism, 17, 47, 67, 87...
Sliding rod, 18...Wheel shaft forced displacement mechanism, 25...
Actuator, 28... clutch, 29... rotary drive device.

Claims (1)

[Scope of Claims] 1. Wheel supports 6, 36, 56 are supported by rotary shafts 7, 37, 57 in the body 1 so as to be rotatable around a vertical axis, and wheels 9 are attached to the wheel supports at both ends. , 39, 59 rotatably supported by the link mechanism 11 so as to be movable in parallel in the horizontal direction. The rotary shaft of the wheel support is connected to a rotary drive device 29 on the fuselage via a clutch 28.
In the one connected to the wheel support body, sliding rods 17, 47,
67 and 87 are slidably inserted into this sliding rod,
A wheel shaft forced displacement mechanism 18 that acts on the link mechanism to move and hold the horizontal wheel shaft at the turning position is provided, and an actuator 25 is provided on the body side that drives the sliding rod in the axial direction. The caster features active direction change.