JPH0634093U - Universal joint for small diameter pipe propulsion - Google Patents

Abstract

(57) [Summary] [Purpose] While reducing the surface pressure of the torque transmission surface,
The purpose is to alleviate stress concentration. [Structure] In a small-diameter pipe propelling machine, in which the sand excavated by a cutter head provided at the tip of the leading pipe is carried out by a screw conveyor provided in a small-diameter pipe subsequent to the leading pipe. A universal joint for connecting the screw shafts 1 and 2 is provided with a fitting portion 1a having peaks 1b, 2b and valleys 1c, 2c alternately arranged in the circumferential direction at the ends of the screw shafts 1, 2 to be connected to each other. 2a is formed, and the peaks 1b, 2b and the valleys 1c, 2c are fitted to each other, and the fitting portions 1a, 2
The reaction force receiving shaft 5 is inserted through the central portion of a, and the screw shafts 1 and 2 are connected via the reaction force receiving shaft 5. 1b,
2b and the valleys 1c and 2c are brought into surface contact with each other,
It is possible to reduce the surface pressure of the torque transmission surface and reduce the concentration of stress on the valley.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a universal joint for a small diameter pipe propulsion machine with an improved torque transmission structure.

[0002]

[Prior art]

 When burying a small-diameter pipe in the ground using a conventional small-diameter pipe propulsion machine, the tip pipe c is attached to the tip by the small-diameter pipe propulsion machine b installed in the starting shaft a as shown in FIG. The small diameter pipe d is propelled into the ground. A cutter head e is provided at the tip of the tip conduit c, and the earth and sand excavated by the cutter head e is carried out by a screw conveyor f provided in the small diameter pipe d. The driving device g of the small diameter pipe propulsion device b is connected via the screw shaft h of the screw conveyor f, and the driving device g rotates the cutter head e through the screw shaft h. There is.

Further, the screw conveyor e is divided for each unit length of the small diameter pipe d, and is connected when the small diameter pipe d is replenished. Therefore, torque transmission is performed between the screw shafts h. In order to be able to do so, they are connected by a universal joint i as shown in FIGS. The universal joint i has a structure in which the fitting portion k of the joint main body is fitted in the hexagonal fitting hole j formed on the screw shaft h side and the bolt m is penetrated between the two parts. Is designed to be performed using the width across flats.

[0004]

[Problems to be solved by the device]

In the conventional universal joint described above, when torque is transmitted in a state where there is a swing angle θ ₀ between the front and rear screw shafts h as shown in (a) of FIG. 4, the fitting hole j on the screw shaft h side is fitted. Will transmit torque while repeating the deformation shown by the solid and phantom lines in Fig. 5 (a). As a result, the top of the hexagon becomes a notch and the notch n is shown in Fig. 5 (b). As shown, the stress was concentrated and this part was prone to breakage.

Further, since the torque transmission is performed by point contact, the surface pressure of the transmission surface becomes extremely high, and the transmission surface is liable to be prematurely depressed, and peeling may occur, resulting in a short service life. . The present invention has been made in order to improve such a problem, and an object thereof is to provide a universal joint for a small-diameter pipe propulsion machine, which has a significantly improved life by improving the torque transmission structure. .

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has a small diameter so that the sand excavated by the cutter head provided at the tip of the leading conduit is carried out by the screw conveyor provided in the small diameter pipe following the leading conduit. In a pipe propulsion machine, a universal joint that connects the screw shafts of the screw conveyor is formed, and a fitting part that has peaks and valleys in the circumferential direction alternately is formed at the ends of the screw shafts that should be connected to each other. In addition, these peaks and troughs are fitted together, the reaction force receiving shaft is inserted through the center of each fitting, and the screw shafts are connected via this reaction force receiving shaft. I did it.

[0007]

[Action]

 With the above configuration, torque is transmitted between the peaks and troughs that fit together, so that the torque transmission surface does not come into surface contact and the surface pressure does not rise abnormally, and stress concentration is eased. Therefore, it is possible to prevent the durability of the fitting portion from decreasing.

[0008]

【Example】

 An embodiment of the present invention will be described in detail with reference to the drawings shown in FIG. FIG. 5 is a cross-sectional view of a universal joint used for a screw conveyor of a small-diameter pipe propulsion machine, and FIG. 6 is an exploded perspective view of the same, in which 1 and 2 indicate screw shafts. Fitting portions 1a, 2a are formed at the ends of the screw shafts 1, 2 for fitting with each other. As shown in FIG. 7, the fitting portions 1a and 2a have peaks 1b and 2b and valleys 1c and 2c which are alternately formed in the circumferential direction. Of the fitting portion 2a, and the ridge portion 2b of the other fitting portion 2a is fitted to the valley portion 1c of the one fitting portion 1a. The outer diameter of 2a is smaller than the outer diameters of the screw shafts 1 and 2, and the tubular collar 3 is fitted to the fitting portions 1a and 2a having the small diameter.

Dust seals 4 are provided on the inner peripheral surfaces of both ends of the collar 3 to prevent dirt and sand from entering and at the same time prevent lubricant such as grease filled in the fitting portions 1a and 2a from leaking. In addition, the inner diameters of the fitting portions 1a and 2a are smaller than the inner diameters of the screw shafts 1 and 2, and a hollow reaction force receiving shaft whose outer diameter is sufficiently smaller than the inner diameter is provided on the inner peripheral portion of the small diameter. 5 is inserted.

Both ends of the reaction force receiving shaft 5 are projected into the screw shafts 1 and 2, a reaction force receiving ring 6 is fitted to both end sides thereof, and a nut screwed to both ends of the reaction force receiving shaft 5. It is designed so that it does not come off due to 7. The reaction force receiving ring 6 has a spherical surface portion 6a, and the spherical surface portion 6a is locked to step portions 1d and 2d formed on the inner peripheral portions of the fitting portions 1a and 2a. The spherical surface 6a of the reaction force receiving ring 6 and the spherical bush 8 are provided with a seal 9 for preventing the lubricant enclosed in the fitting portions 1a, 2a from leaking.

Next, the operation will be described. The torque applied to one screw shaft 1 is transmitted to the other screw shaft 2 via the fitting portions 1a and 2a. Further, when one screw shaft 1 is swung with respect to the other screw shaft 1 as shown in FIG. 8 by controlling the direction of the leading conduit, etc., each of the swing shafts ₀ , 2 has a swing angle θ _0. However, since the spherical surface 6a of the reaction force receiving ring 6 provided at both ends of the reaction force receiving shaft 5 slides and absorbs this, the torque is the same as when the centers of the screw shafts 1 and 2 are aligned. Can communicate.

On the other hand, by engaging the fitting portions 1a and 2a with the ridge portions 1b and 2b and the valley portions 1c and 2c, it is possible to prevent stress from being concentrated. Explaining the reason for this, as shown in FIG. 9 (a), when the fitting portions 1a, 2a are formed of a convex portion and a concave portion and are meshed with each other, a concentrated stress is generated at the base portion A of the convex portion. Then, the strength of this portion is significantly reduced. Therefore, as in this invention, the fitting portions 1a and 2a are formed by the peak portions 1b and 2b and the valley portions 1c and 2c, and are engaged with each other. At this time, assuming that the length of the torque transmission surface is S, the height is h, and the transmission torque is N, the fitting portions 1a and 2a are peak portions 1b and 2b and trough portions 1c and 2c. ) transmission torque N in the shown Suyo is a component force to the torque transmission faces f _'T and f _P. The length S'of the torque transmission surface is S '= S / sin θ, and the transmission torque is N' = f _T / S. And the surface pressure is

[0013]

[Equation 1]

Therefore, the surface pressures of σ90 ° and σθ become equal. Note that f _P is a tensile force generated on the reaction force receiving shaft 5, and does not occur when the fitting portions 1a, 2a have an uneven shape. That is, even when the fitting portions 1a and 2a are the peak portions 1b and 2b and the trough portions 1c and 2c, the surface pressures generated on the torque transmitting surfaces are equal and the angle of the stress concentration portion A increases, so that the stress concentration portions concentrate. The stress can be reduced.

[0015]

[Effect of device]

 As described in detail above, the present invention forms a fitting portion composed of a peak portion and a valley portion at the ends of screw shafts which are connected to each other, and fits these fitting portions to each other, and Since they are connected via a reaction force receiving shaft, the torque transmission surface becomes surface contact during torque transmission and torque is transmitted, so the surface pressure can be significantly reduced compared to the conventional point contact transmission. You can This prevents the torque transmission surface from slumping or peeling off early, which can significantly improve the life of the universal joint and also reduce stress concentration, thereby improving strength and durability due to stress concentration. It is possible to prevent the deterioration. Also, since the swing angle can be made large, the direction can be easily corrected.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a conventional small-diameter pipe propulsion device.

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

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

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

5 (a) is an explanatory diagram showing stress strain of a conventional universal joint. FIG. (B) It is explanatory drawing which shows the stress concentration of the conventional universal joint.

FIG. 6 is a vertical sectional view of a universal joint according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view of a universal joint according to an embodiment of the present invention.

FIG. 8 is an operation explanatory view of the universal joint according to the embodiment of the present invention.

FIG. 9 (a) is an explanatory diagram showing the surface pressure of the torque transmission surface when the fitting portion is made uneven. (B) It is explanatory drawing which shows the surface pressure of the torque transmission surface of the fitting part which comprised the fitting part by the peak part and the trough part.

[Explanation of symbols]

 1 screw shaft 1a fitting part 1b crest part 1c valley part 2 screw shaft 2a fitting part 2b crest part 2c trough part 5 reaction force receiving shaft

Claims (1)

[Scope of utility model registration request] 1. A small-diameter pipe propelling machine in which the earth and sand excavated by a cutter head provided at the tip of the leading pipe is carried out by a screw conveyor provided in a small-diameter pipe following the leading pipe. A universal joint for connecting the screw shafts 1 and 2 of the conveyor, and a fitting portion having peaks 1b and 2b and valleys 1c and 2c alternately in the circumferential direction at the ends of the screw shafts 1 and 2 to be connected to each other. 1a and 2a are formed, and these ridges 1b and 2b are formed.
And the troughs 1c and 2c are fitted to each other, and each fitting 1
A universal joint for a small-diameter pipe propulsion machine, in which the reaction force receiving shaft 5 is inserted through the central portions of a and 2a, and the screw shafts 1 and 2 are connected via the reaction force receiving shaft 5. .