JPH0459161B2 - - 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] A generally used caster has a wheel support supporting a wheel that rotates around a horizontal wheel axis, which is rotatable around a vertical axis. It is supported by a wheel support at a position slightly away from the axis.
Such a known caster turns when the vehicle body turns, and does not require any control.
Although it is very convenient, when an omnidirectional vehicle attempts to make a sharp turn at a near right angle, the turning becomes unsmooth, and at the same time, it is necessary to accurately control the attitude of the vehicle. Particularly when turning at a steep angle under heavy load, unreasonable force is applied to each part of the caster, making it difficult to turn the caster and causing damage.

Casters have also been known in the past, in which the horizontal wheel axle that supports the wheels is supported so that it can move in parallel on its support, making it easier to move backwards. When doing so, the same problem as above occurs.

[Problem to be Solved by the Invention] The technical problem of the present invention is to be able to change direction of the wheels without resistance even when the vehicle body is stopped, without affecting the attitude of the vehicle body, and furthermore, even when the vehicle body is stopped, it is possible to change the direction of the wheels without any resistance. The object of the present invention is to obtain an active caster capable of turning direction, which sometimes does not require special control and can be used in the same way as a conventional caster.

[Means for Solving the Problems] To solve the above problems, the active direction changeable caster of the present invention has a wheel support that is rotatably supported around a vertical axis by a rotary shaft portion, and a caster at both ends. A horizontal wheel axle that rotatably supports a wheel is supported so as to be movable in parallel in the horizontal direction, and the horizontal wheel axle is moved to a turning position where it intersects the vertical axis, and a pair of driven wheels are moved in parallel to both sides from the turning position. The present invention is constructed by providing a wheel position control device including a drive device for shifting the wheel support to a rotational position, and connecting the rotation shaft of the wheel support to a rotational drive source via a clutch.

[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 wheel support is connected to a rotational drive source such as a motor by a clutch, and then the horizontal wheel axle is moved to the turning position by the drive device such as a motor in the wheel position control device, and the horizontal wheel axle is moved to the turning position. Rotate the wheel support so that the wheels face the desired direction of travel. In this case, since the friction between the wheel and the ground surface is minimal, the wheel support can smoothly rotate around the vertical axis around which it rotates without any resistance, and it can also rotate around the vertical axis around the vertical axis. Since the wheels turn, it does not affect the attitude of the vehicle body.

To run the vehicle from this state, the clutch disconnects the wheel support from the rotational drive source.
Furthermore, the horizontal wheel axle is moved to a driven rotation position in a direction opposite to the direction in which the vehicle is traveling, thereby causing the vehicle to travel in the desired direction. 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.

[Embodiment] FIGS. 1 and 2 show an embodiment of the present invention, in which bearings 3, 4,
The wheel support body 6 is provided with a rotary shaft portion 7 rotatably supported via a wheel support member 5 . This wheel support 6 is
It supports a horizontal wheel axle 8 on which a pair of wheels 9, 9 are rotatably attached at both ends. 10, 10, and the horizontal wheel shaft 8 has a turning position directly below the rotating shaft part 7 of the wheel support 6, and a pair of driven wheels that are parallelly moved on both sides from the turning position. A wheel position control device 12 for forcibly displacing the rotational position is attached.

The wheel position control device 12 allows a cylindrical cam member 13 having a spiral cam groove 14 around it to be rotationally controlled by a drive device consisting of a motor 15 via a reducer 16, and projects onto a horizontal wheel shaft 8. A driven protrusion 17 provided therein is fitted into a cam groove 14, and the cam groove 14 has a slight circumferential linear shape at a position directly below the rotating shaft portion 7 in the wheel support body 6 and at both end positions of the cam member 13. Groove portions 14a, 14b, 14b
and curved grooves 14c, 14c as appropriate between them.
It has the form of being connected by. Therefore, when the cylindrical cam member 13 is rotated by the rotational drive of the motor 15, the driven protrusion 17 on the horizontal wheel shaft 8 does not need to accurately control the rotation of the motor 15.
can be transposed to the desired position.

The wheel support 6 is held rotatably around a vertical axis by its rotating shaft portion 7;
The rotary shaft portion 7 is connected to a rotary drive source such as a motor 20 via a clutch 18 and a speed reducer 19 in order to drive the rotary shaft portion 7 in rotation for turning the wheels 9, 9.
Therefore, when the clutch 18 connects the motor 20 and the rotating shaft section 7 and rotates the motor 20 with the horizontal wheel shaft 8 held at the central turning position, the wheels 9, 9
Since the friction between the wheels 9 and the ground contact surface becomes small, the direction of the wheels 9, 9 can be changed without resistance even when the vehicle body is stopped. Moreover, since the wheels 9, 9 turn around the vertical axis, the turning of the wheels does not affect the attitude of the vehicle body. Furthermore, by disconnecting the motor 20 from the rotating shaft portion 7 by the clutch 18 while holding the horizontal wheel shaft 8 in the driven rotation position, it can be used as having the same function as a normal caster.

3 and 4 show a case where a Geneva gear mechanism is used as the wheel position control device.

In this wheel position control device, a cylinder 31 rotatably supported by a pin 30 on a wheel support (not shown) is used as a drive device for shifting the horizontal wheel shaft between a turning position and a driven rotation position. The tip of the rod 32 is similarly connected to a rocking body 34 rotatably attached to a wheel support with a pin 33, and a pair of Geneva pins 35, 35 provided on this rocking body 34 are connected to a pair of concave grooves 35 in a Geneva gear 36. .
A concave arc portion 3 facing the circular arc portion 38 between 7 and 37
There are 9. The Geneva gear 36 has its central portion rotatably supported by a wheel support body through a shaft 42, and has a recessed groove 41 in which a driven protrusion 40 protruding from the horizontal wheel shaft engages. .

Therefore, the oscillating body 34 is
3, the groove 41 of the Geneva gear 36 allows the driven projection 4 of the horizontal wheel shaft to
0 is located at the central turning position, that is, directly below the rotating shaft of the wheel support, and when the cylinder 31 is extended and the swinging body 34 is in the position shown in FIG.
The driven projection 40 moves to one driven rotation position, and further moves to the other driven rotation position when the cylinder 31 is shortened.

When this Geneva gear mechanism is used, when the oscillating body 34 is in the neutral position as shown in FIG. 39 ensures that the Geneva gear 36 is accurately held in the neutral position.

The embodiment shown in FIG. 5 schematically shows a case where a pseudo-linear link mechanism is used as the wheel position control device.

This link mechanism includes a link 5 to a wheel support 50.
1 and 52 are rotatably attached, and the end and intermediate position of a third link 53 are rotatably attached to the tips of these links 51 and 52, and a horizontal wheel axle 54 is attached to the tip of the third link 53. By giving these links the dimensional relationship AD/CO=BC/DO, the third link 5
3, that is, the horizontal wheel shaft 54 supporting the wheel 55
can be given horizontal movement. This link mechanism is driven by a cylinder 56 that can be controlled in three positions.
etc. can be used. Further, as shown in the figure, the link mechanisms can be arranged symmetrically on both sides of the horizontal wheel axle 54.

In the wheel position control device using the Geneva gear mechanism or pseudo-linear link mechanism described above, it is necessary to hold the driven protrusion of the horizontal wheel shaft in three positions.
As a driving device for this purpose, as shown in FIG. 6, a structure in which two cylinders 60 and 61 are connected and one or both of them are operated, or a solenoid capable of holding three positions may be used. Can be done. However, without being limited to these,
For example, even in the case of an actuator that holds two positions, a means for positioning control may be added to an intermediate position.

Power, electrical signals, fluid pressure, etc., are supplied to these actuators through the rotating shaft of the wheel support, and in the case of power and electrical signals, they are supplied via slip rings as appropriate, and in the case of fluid pressure, they are supplied through slip rings, etc. Fluid will be supplied via the seal joint.

The above-mentioned caster can be used for various purposes, but it can be used extremely effectively in the following cases.

7A and 7B show the state in which the left and right sides of the vehicle body 70 are used for a vehicle that needs to move in the opposite direction and turn in a fixed position, such as a general heavy goods transport vehicle or a forklift. A pair of drive wheels 71, 7
1, and casters 72, 7 having the above configuration.
2 are placed in the front and back. Figure A shows the state when the vehicle is traveling straight in the direction of the arrow, and Figure B shows the state when the vehicle body 70 is turned in a fixed position.

Moreover, FIGS. 8A and 8B show a state in which the above-mentioned casters are used in an omnidirectional vehicle, in which driving wheels 81, 81 are connected to steering shafts 82, 81 relative to a vehicle body 80.
Since it is installed so that it can rotate around 2, it can not only move straight as shown in Figure A, move laterally as shown in Figure B, or move in any other arbitrary direction, but also as shown in Figure 7 B. Such fixed position rotations can also be performed.

When changing the direction of the caster from the state shown in each A of FIGS. 7 and 8 to a large angle such as a right angle, such as the state shown in each B of FIG.
The following operations allow you to change direction without resistance while the vehicle remains stationary.

That is, when changing the direction of the caster, first,
The wheel supports 6 and 50 are connected to a rotational drive source such as a motor 20 by a clutch 18, and further connected to a motor 15, a cylinder 31, and a cylinder 31 in the wheel position control device 12.
56 or the like, the horizontal wheel axles 8, 54 are moved to a turning position directly below the vertical axis on which the wheel supports 6, 50 turn, and in this state, the wheels 9, 55 are oriented in the desired direction of travel. The wheel supports 6, 50 are rotated by the rotational drive source in this manner. In this case, since the friction between the wheels 9 and 55 and the ground contact surface is small, it is possible to smoothly rotate the wheels 9 and 55 around the vertical axis around which the wheel supports 6 and 50 rotate without resistance. can. Moreover, since the wheels turn around the vertical axis, the turning of the wheels does not affect the attitude of the vehicle body.

When running the vehicle, the clutch 18 disconnects the wheel supports 6, 50 from the rotational drive source such as the motor 20, and further connects the horizontal wheel axles 8, 54.
is moved to a driven rotation position in the direction opposite to the traveling direction of the vehicle, and then the vehicle body is advanced in the desired direction. 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.

Note that even when the caster is used for various other purposes, it can be effectively operated in the same manner as described above.

[Effects of the Invention] According to the caster of the present invention detailed above, the direction of the caster can be changed without resistance even when the vehicle body is stopped, and the wheels can be rotated around the vertical axis around which the wheel support rotates. Since the wheels turn, the turning of the wheels does not affect the attitude of the vehicle body, and there is no need for special control during normal driving, so it can be used in the same way as conventional casters.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a caster capable of actively changing direction according to the present invention, FIG. 2 is a vertical sectional view of the main part thereof, and FIGS. 3 and 4 show configuration examples of the wheel position control device in different operating states. 5 is a configuration diagram of another wheel position control device, FIG. 6 is a configuration diagram of a drive device that drives the wheel position control device, and FIGS. It is an explanatory view showing an example of use of a caster. 6, 50...Wheel support body, 7...Rotating shaft part,
8,54...Horizontal wheel axle, 9,55...Wheel, 1
2...Wheel position control device, 18...Clutch.

Claims (1)

[Claims] 1. Horizontal wheel axles 8, 54, which rotatably support wheels 9, 55 at both ends, are attached horizontally to wheel supports 6, 50, which are rotatably supported around a vertical axis by rotating shafts 7. A wheel position that is supported so as to be able to move in parallel and is equipped with a drive device that shifts the horizontal wheel axles 8 and 54 between a turning position intersecting the vertical axis and a pair of driven rotational positions that are parallelly moved on both sides from the turning position. A control device 12 is provided,
A caster capable of actively changing direction, characterized in that the rotating shaft portion 7 of the wheel supports 6, 50 is connected to a rotational drive source via a clutch 18.