JP2554986Y2 - Sealing device for universal joints in small-diameter pipe thrusters - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint sealing device for a small-diameter pipe propulsion machine in which a small-diameter pipe is buried underground.

[0002]

2. Description of the Related Art Conventionally, a small-diameter pipe propulsion device for burying a small-diameter pipe in the ground has a propulsion device b in a starting shaft a as shown in FIG.
Has been installed, and the propulsion device has a leading conduit c at the tip.
Is propelled into the ground. Also, a cutter head d is provided at the tip of the leading conduit c,
The cutter head d is driven to rotate by a drive motor e provided in the propulsion device b via a screw conveyor f, and the earth and sand excavated by the cutter head d is introduced into a front pipe c. After being taken in, it is conveyed to the starting shaft a by the screw conveyor f and discharged to the ground.

On the other hand, in the conventional small-diameter pipe propulsion device, the front portion of the front conduit c is bendable so that it can be corrected when the propulsion direction of the front conduit c deviates from the planned line. For this reason,
Screw conveyor f for transmitting rotation to cutter head d
(A) and (b) in FIG. 2 and (a), (b) and
A universal joint g as shown in FIG. 4 is provided, and the screw shaft h of the screw conveyor f also bends following the bending of the leading conduit c. Further, the conventional universal joint g has a structure in which both ends are fitted into a fitting convex portion i having a hexagonal shape and a fitting concave portion j on the screw shaft h side and are connected by a bolt k. The portion is provided with an O-ring m which is pressed against the inner peripheral surface of the fitting recess j.

[0004]

However, in the above-mentioned conventional universal joint g, when the screw shaft h is bent as shown in FIG. 4, the crushing allowance of the O-ring m is large, so that the O-ring having a large wire diameter is used. m, and a large gap n is generated between the ends of the screw shaft h, so that the O-ring m is damaged by earth and sand penetrating from the gap n, and the sealing effect is reduced early. there were. The present invention has been made for the purpose of improving the above-mentioned conventional problems, and an object thereof is to provide a universal joint of a small-diameter pipe propulsion machine capable of obtaining a sufficient sealing effect even with an O-ring having a small wire diameter. .

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention makes it possible to bend the distal end portion of a front conduit which is mounted on the distal end of a small-diameter pipe and is propelled into the ground. In a small-diameter pipe propulsion machine that is connected to a screw shaft of a screw conveyor provided by a universal joint so as to bend following the bending of the leading conduit, between the screw shafts connected by the universal joint,
A floating seal comprising an O-ring and a floating collar elastically supported by the O-ring is provided.

[0006]

According to the above construction, even if the screw shaft is bent by the universal joint following the swing of the leading conduit, the O-ring with a small wire diameter can be used because the crushing allowance of the O-ring is small. Since the gap is also small, it is possible to prevent the O-ring from being damaged due to the intrusion of earth and sand and the sealing effect from being deteriorated early.

[0007]

One embodiment of the present invention will be described in detail with reference to FIGS. FIG. 5 shows a universal joint for connecting a screw shaft of a screw conveyor provided in a front pipe (not shown) of a small-diameter pipe propulsion machine, and has a hexagonal fitting in the end of each screw shaft 1, 2. Joint recesses 1a, 2
The inner peripheral surfaces of the fitting recesses 1a, 2a are formed with tapered surfaces 1b, 2b having a large diameter on the end side. Both ends of the universal joint 3 are fitted into these fitting recesses 1a, 2a.

The universal joint 3 has hexagonal fitting projections 3a and 3b formed at both ends, and a bolt hole 3c is formed in each of the fitting projections 3a and 3b in a direction perpendicular to the axis. Bolt holes 1c, 2c formed in the ends of the screw shafts 1, 2 and fitting projections 3a, 3b
The screw shafts 1 and 2 are flexibly connected via the universal joint 3 by inserting the bolts 4 into the bolt holes 3c formed in the screw holes 3c.

On the other hand, small diameter portions 1d and 2d are formed on the outer periphery of the screw shafts 1 and 2 on the end side.
A floating seal 5 is provided between d and 2d. The floating seal 5 includes an O-ring 5a and a floating collar 5b. The O-ring 5a is formed in annular grooves 1e, 2e formed on the outer peripheral surfaces of the small diameter portions 1d, 2d.
It is inserted inside. The above floating collar 5
b is formed in an annular shape, and a ridge 5c protrudes in the circumferential direction at the center of the inner periphery. Then, the small-diameter portions 1d of the screw shafts 1 and 2 from both ends of the floating collar 5b,
2d is inserted, and O is accommodated in the annular grooves 1e and 2e.
The ring 5a is pressed against the inner peripheral surface of the floating collar 5b.

Next, the operation will be described. The rotation applied by a driving device (not shown) is applied to the other screw shaft 2 via the universal joint from one screw shaft 1.
To the cutter head (not shown) to rotate the cutter head. Also, even if a tensile force acts on the screw shafts 1 and 2, the screw shafts 1 and 2 and the universal joint are connected with the bolts 4 so that the screw shafts 1 and 2 do not come off, and between the screw shafts 1 and 2. The provided floating seal 5 prevents earth and sand from entering between the screw shafts 1 and 2 and the universal joint 3.

On the other hand, when the front conduit (not shown) is swung due to a direction correction or the like, the screw shafts 1 and 2 are also bent as shown in FIG. However, since the floating seal 5 is provided between the screw shafts 1 and 2, the crushing allowance of each O-ring 5a is small with respect to the swing angle θ, so that even the O-ring 5a having a small wire diameter has a sufficient seal. The effect will be obtained. Since the gaps between the screw shafts 1 and 2 and the floating collar 5b are also small, earth and sand are less likely to enter through these gaps.

[0012]

[Effects of the Invention] As described above in detail, the floating seal is provided between the screw shafts connected by the universal joint, so that even if the screw shaft is bent following the swing of the leading pipe, The squeeze allowance of the O-ring provided on the floating seal is reduced, and a sufficient sealing effect can be obtained even with an O-ring having a small wire diameter, which is economical. In addition, since there is no large gap between the screw shaft and the floating collar of the floating seal, O
Problems such as early deterioration of the sealing effect due to damage to the ring can be solved, and a large swing angle can be obtained by adopting the floating seal, so that the direction of the leading conduit can be efficiently corrected. In addition, since a large force is not applied to the end of the screw shaft during bending, even if this part is made thinner in order to increase the swing angle, there is no risk of damage due to external force, and the cross-sectional shape of the screw shaft end If the change is made smoothly, stress concentration and settling do not occur, so that a decrease in strength can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a conventional small-diameter pipe thruster.

FIG. 2A is a longitudinal sectional view of a conventional universal joint. (B) It is sectional drawing which follows the AA line of FIG.2 (a).

FIG. 3 (a) is a cross-sectional view of a conventional universal joint. (B) It is sectional drawing which follows the BB line | wire of FIG.3 (a).

FIG. 4 is an operation explanatory view of a conventional universal joint.

FIG. 5 is a sectional view showing a sealing device for a universal joint according to an embodiment of the present invention.

FIG. 6A is a longitudinal sectional view of a universal joint employing the sealing device according to one embodiment of the present invention. (B) It is sectional drawing which follows the CC line | wire of FIG.6 (a).

FIG. 7A is a cross-sectional view of a universal joint employing the sealing device according to one embodiment of the present invention. (B) It is sectional drawing which follows the DD line of (a) of FIG.

FIG. 8 is a diagram illustrating the operation of the sealing device according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw shaft 2 Screw shaft 3 Universal joint 5 Floating seal 5a O-ring 5b Floating collar

Claims (1)

(57) [Scope of request for utility model registration] 1. A front end portion of a front pipe which is attached to a front end of a small-diameter pipe and propelled into the ground is made bendable, and a screw shaft 1 of a screw conveyor provided in the front pipe is provided.
2 is a small-diameter pipe propulsion machine connected by a universal joint 3 so as to bend following the bending of the leading conduit,
A universal joint sealing device comprising a floating seal 5 comprising an O-ring 5a and a floating collar 5b elastically supported by the O-ring 5a between the screw shafts 1 and 2 connected by the universal joint 3.