JPH05116654A - Travel mechanism - Google Patents

Abstract

PURPOSE:To enable traveling in small diameter piping while adjusting pressing force to the pipe wall. CONSTITUTION:Four endless belts 7, 7... are disposed in cross shape around a screw shaft 4 mounted in the rotatably driven state, and meshed with the screw part 4a of the screw shaft 4. At this time, bearings 10 for supporting the endless belts 7 are energized by torsion coil springs 17 in such a way as to protrude outward. The screw shaft 4 is rotatory-driven by a motor 2, and simultaneously, the endless belts 7 are partially pressed to the inner wall W of a pipe. The rotation of the screw shaft 4 is thereby converted into the rotation of the endless belts 7 in the axial direction of the pipe. As a result, the torque of the endless belts 7 functions as the propulsion force of a device by the drag from the pipe wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling mechanism and, more particularly, to a traveling mechanism capable of traveling in a narrow pipe having a small diameter while adjusting a pressing force against a wall during traveling.

[0002]

2. Description of the Related Art In recent years, a small mobile inspection vehicle for inspecting the inside of a pipe having a complicated arrangement has been developed and put into practical use in a nuclear power plant, a chemical plant or the like. Various types such as a wheel type, a crawler type, and a wiping type have been developed as the traveling system of these mobile inspection vehicles.

Further, in this type of piping, there are many portions where the deposit adheres to the inner wall of the tube and the cross section is blocked, or the diameter of the tube changes like a reducer. For this reason, a traveling mechanism such as an inspection vehicle that can cope with a change in pipe diameter is required. Also,
It is also required to provide a pressing mechanism for pressing the traveling mechanism portion against the inner wall of the pipe so that a vertical pipe or the like can be safely climbed.

In order to meet these demands, there has been proposed a device in which a shock absorbing device such as a spring is interposed between a wheel and a drive mechanism. According to this traveling device, the spring can be deformed to absorb the change in the pipe diameter. Further, there is a traveling device in which each wheel is provided with a pressing drive device for the inner wall of the pipe, and a large driving force is secured by the frictional force between the wheel and the wall surface, thereby making it possible to climb a vertical pipe.

[0005]

However, all the inspection vehicles are intended for pipes having a relatively large diameter,
When the above-mentioned traveling mechanism is incorporated, the entire apparatus becomes large and it is difficult to cope with the downsizing of the apparatus, and it is strongly desired to develop a traveling mechanism for a mobile inspection vehicle for pipes having a smaller diameter.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a traveling mechanism that can travel in a pipe having a smaller diameter with a simple structure.

[0007]

In order to achieve the above object, the present invention provides a screw shaft which can be rotationally driven, and a screw shaft which is arranged radially around the screw shaft and meshes with the screw shaft. A plurality of endless belts that can be driven by rotation, a plurality of rotary bearings that support the endless belts, and a biasing mechanism that biases at least one of the rotary bearings in the radial direction of the screw shaft. It is characterized by having.

[0008]

According to the present invention, a plurality of endless belts are radially arranged around a screw shaft mounted so as to be rotatable and are engaged with the screw shaft to be driven by the rotation of the screw shaft. At least one of a plurality of rotary bearings supporting a belt-shaped belt
Since the individual members are urged by the urging mechanism to project in the radial direction of the screw shaft and a part of the endless belt is pressed against the running surface, the endless belt radially arranged on the outer periphery of the screw shaft and meshed with the screw shaft. The endless belt rotates, converts the rotational movement of the screw shaft into the rotational movement of the endless belt in the tube axis direction, and allows the endless belt to move in the tube axis direction by contacting the tube wall. As a result, it is possible to reduce mechanical components such as a gear train, which causes an increase in the size of the traveling mechanism, and to realize an extremely small traveling mechanism by the minimum necessary constituent transmission elements of the screw shaft and the endless belt. At this time, since the endless belt is pressed against the wall surface, the drag force from the inner wall of the pipe acts and the propulsive force necessary for running can be secured, and the device is made compact by using the torsion coil spring as the urging mechanism. Can be Further, it is possible to cope with a change in the pipe diameter by deforming the torsion coil spring which is in a protruding state toward the outer periphery in the pipe axis direction, inward.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a traveling mechanism according to the present invention is shown in FIG.
It will be described with reference to FIGS.

FIG. 1 and FIG. 2 show a traveling mechanism 1 which is a part of a traveling device arranged inside a pipe. A screw shaft 4 of the traveling mechanism 1 is attached to a rotary shaft of an electric motor 2 which is a drive source via a coupling 3. Both ends of the screw shaft 4 are rotatably supported by bearings 5 and 6, and the bearings 5 and 6 are fitted to both ends of the bearing frame F having a substantially L-shaped cross section in the pipe axial direction. There is. Further, the screw portion 4a of the screw shaft 4
A part of the endless belt 7 is meshed with. The endless belt 7 is composed of a rubber timing belt, and is supported in its inner peripheral position in a state where a predetermined tension is applied by bearings 8, 9 and 10. At this time, the shaft ends of the shafts 11 and 12 supporting the bearings 8 and 9 have oblong holes 14 formed in the bearing frame F as shown in FIG.
The shafts 11 and 12 are slidable in the tube axis direction, that is, in the traveling axis direction of the traveling mechanism main body 1, by being engaged with and supported by 15. On the other hand, the shaft 1 supporting the bearing 10
As shown in FIGS. 1 and 3, 3 is engaged with an engaging groove 16 formed in the inner surface of the bearing frame F in the direction perpendicular to the tube axis, whereby the shaft 13 can slide in the direction perpendicular to the tube axis. You can

The relationship between the bearings 8, 9, 10 and the torsion coil spring 17 in the inner peripheral portion of the endless belt 7 is shown in FIG.
And FIG. 4 will be described. As shown in FIG. 4, the endless belt 7 is stretched by bearings 8, 9 and 10 which are biased in a predetermined direction by a torsion coil spring 17, and its shape is defined. That is, the shafts 11, 12, and 13 that support the bearings 8, 9, and 10 are wound around the shafts so that the coil portion of the torsion coil spring 17 is symmetrical about the shaft 13, and the bearings 8 and 9 are also bearings. The bearing 10 is biased so as to face each other with the pinch 10 in between, and the bearing 10 is biased by the torsion coil spring 17 so as to project in the radial direction of the screw shaft 4, that is, toward the inner wall of the pipe. At this time, the outer diameters of the bearings 8, 9 and 10 are the same as those of the torsion coil spring 17.
Is set to be larger than the outer diameter of the coil portion, so that the endless belt 7 is stretched so as to form a flat triangular shape, and securely supported by the outer peripheral portions of the bearings 8, 9, and 10.

Further, as shown in FIG. 2, the endless belt 7 configured as described above is arranged in a cross shape with a 90 ° interval with respect to the cross section, and is provided with four bearing frames F,
The shaft ends of the shafts 11, 12 and 13 are supported by F.

In this state, the output from the electric motor 2 is transmitted to the screw shaft 4 via the coupling 3, and the rotational force in the tube axis direction is applied to the endless belt 7 meshed with the screw portion 4a of the screw shaft 4. Is given. At this time, the bearing 10 is in a state of protruding with respect to the pipe wall W, and an appropriate pressing force acts on the pipe wall W from the endless belt 7, and the drag force from the pipe wall W secures the propulsive force in the pipe axial direction. It

In the free state in which the endless belt 7 does not come into contact with the tube wall, the shape of the endless belt 7 in the free state before the biasing mounting of the torsion coil spring 17 and the oblong hole 14 formed in the bearing frame F, The distance L between the shafts 11 and 12 determines the distance L between the shafts 11 and 12 to be the shortest. The shaft 13 is uniquely set to a predetermined height of the engagement groove 16 in correspondence with the distance L between the shafts. When the traveling mechanism 1 in this state reaches a portion where the pipe diameter is small, the drag force from the pipe wall W acting on the protruding bearing portion 10 increases, and the torsion coil spring 17 is deformed toward the central axis of the device. As a result, the inter-axial distance L between the shafts 11 and 12 expands using the oblong holes 14 and 15 as guides, and the shaft 13 that supports the bearing 10 slides along the engagement groove 16 in the central axis direction. As a result, the distance D between the outer edges of the endless belts 7 facing each other is reduced, and it is possible to cope with the reduction of the pipe diameter (see FIG. 3).

It should be noted that a traveling mechanism having a structure in which three endless belts 7 are arranged around the screw shaft 4 at intervals of 120 ° may be used. In this case, the total value of the sliding friction between the endless belt 7 and the screw shaft 4 becomes small, so that a large driving force is generated. Further, as shown in FIG. 5, instead of the torsion coil spring 17, the link 20,
A similar mechanism can be realized by the urging mechanism 23 that is a combination of 21 and the tension spring 22. According to this urging mechanism 23, the tension springs 22 urge the shafts 11 and 12 toward each other, and the distance L between the shafts is determined to be minimum.

Further, as the endless belt, a grooved belt 3 as shown in FIG. 6 is used instead of the above-mentioned timing belt.
It is also possible to use 0. The grooved belt 30 is a resin belt in which a locking groove 31 having a predetermined width is formed in a ladder shape. According to the grooved belt 30, the screw portion 4a is continuous with the locking groove 31 as the screw shaft 4 rotates. To engage,
The belt can be rotated. This grooved belt 30
Has no convex portion compared to the timing belt 7,
When the inner surface of the tube is flexible, it has an advantage that the surface is not damaged.

[0017]

As is apparent from the above description, according to the traveling mechanism of the present invention, a plurality of endless belts are radially arranged around the screw shaft rotatably mounted and mesh with the screw shaft. Then, the endless belt is driven by the rotation of the screw shaft, and at least one of a plurality of rotary bearings supporting the endless belt is urged by an urging mechanism to project in the radial direction of the screw shaft. Since I pressed some of the above against the running surface,
With the minimum required components of the screw shaft and endless belt, it is possible to realize an extremely small traveling mechanism, and it is possible to respond to changes in pipe diameter with the urging mechanism housed inside, which will ensure miniaturization. Produce an effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a traveling mechanism according to the present invention.

FIG. 2 is a front view of the traveling mechanism shown in FIG.

FIG. 3 is a side view of the traveling mechanism shown in FIG.

FIG. 4 is a sectional view taken along line IV-IV of the traveling mechanism shown in FIG.

FIG. 5 is a partial vertical sectional view showing a modified example of the biasing mechanism of the traveling mechanism according to the present invention.

FIG. 6 is a perspective view showing a modified example of the endless belt of the traveling mechanism according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling mechanism 4 Screw shaft 7,30 Endless belt 8,9,10 Bearing 14,15 Oval hole 16 Engaging groove 17,23 Energizing mechanism

Claims (1)

[Claims] 1. A screw shaft which can be rotationally driven, a plurality of endless belts which are arranged radially about the screw shaft and which are meshed with the screw shaft and can be driven by rotation of the screw shaft, and the endless belt. A traveling mechanism comprising: a plurality of rotary bearings that support a belt; and a biasing mechanism that biases at least one of the rotary bearings in the radial direction of the screw shaft.