JPS60238594A - Producton of bit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for making and receiving corn bits used in oil drilling and the like.

Conventional technology For oil drilling, etc., so-called tricone bits are widely used, which consist of three cones supported by three journals erected diagonally toward the center line on the inner surface of the body. ing.

The conventional manufacturing method for this type of bit is shown in Figures 2(a) and (
b) , (explaining the υ order according to cl, (a)
The body 1 of the bit, which is integrally provided with a journal part 2 and a shank part 3 for cutting a thread for screwing the bit into a drill collar provided at the lower end of the drill pipe when in use, is shown on a plane including the longitudinal axis. (b) After finishing the journal part 2, a conical cone 4 having a large number of protrusions 5 on the surface is attached to the journal part 2. (c) The three body parts are integrally joined by welding 6.

It was specially manufactured.

The above manufacturing method not only requires a large amount of welding for the body 1, but also has the disadvantage that the welded portion has a complicated shape, making the construction method difficult and requiring a long construction time. Further, when the cone and journal portion were worn out over time due to use, it was not possible to replace only the cone and journal portion, and the entire bit was discarded, which was uneconomical. Furthermore, since the body and journal portion are made integrally, it is not possible to use a coating material suitable for each purpose and strength.

Problems to be Solved by the Invention In view of the above-mentioned problems of the conventional tricone pit manufacturing method, the present invention is easy to assemble, requires a small amount of welding, and eliminates the problem when the cone and journal parts wear out over time. To provide a rational bit manufacturing method that allows repair and remanufacturing by replacing only the cone and journal part, and allows use of abrasives suitable for the purpose and strength of the body and journal part, respectively. With the goal.

Means for Solving the Problems The bit manufacturing method of the present invention which solves the above-mentioned problems includes: making the body excluding the journal part integrally with a cast member;
The present invention is characterized in that each cone is held at a predetermined mounting position within the body, a journal is fitted into each cone from the outside, each cone is pivotally supported by the journal, and each journal is fixed to the body.

Effect: With the manufacturing method configured as described above, the only welding area is the area where the journal is added to the body, which not only reduces the amount of welding but also facilitates accurate attachment. In addition, by removing the extra edition from the journal body by drilling, cutting, etc., only the worn journal and cone can be easily removed from the body, and a new cone and journal can be replaced using the same method as when making a new one. It becomes possible to install it on the original body and regenerate it.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the embodiment shown in FIG. 1, (a) the pit body 1 excluding the journal portion is made integrally by centrifugal casting. A through hole 1a with a finishing allowance is provided in advance in the part where the journal is to be attached, and then cast, and after casting, it is finished to a predetermined size by poling.

('b) The journal portion 2 is formed separately by forging integrally with the portion 2a of the body 1 that fits into the through hole laK, and the outer peripheral surface of the portion that fits into the hole 1a of the body is finished to a predetermined outer diameter.

(e) The cone 4 is also completed using a separate centrifugal casting method, with the part supported by the journal part 2VC being used as a bearing.

(d) Insert the three cones 4 into predetermined positions in the body 1 and hold them there, insert the journal part 2 from the outside of the body 1, pass through the through hole 1a, and fit it into the cones 4. , apply a pull-out stop using a known method, and then connect the inner surface of the hole 1a of the body 1 and the body 1 of the journal portion 2.
This is completed by fixing the outer peripheral surface of the mounting portion 2a to the mounting portion 2a by welding 5.

The body does not necessarily have to be cast using centrifugal casting, but by using centrifugal casting, it is possible to create a high-quality body that is dense, has no holes, and is comparable to that produced by forging. It is particularly suitable for making pit bodies that require high strength.

The thickness of the part where the journal part 2 is attached to the body 1 is quite thick, the welding area is narrow and a large gap cannot be taken, and the amount of heat input is small to avoid deformation and mutual change due to heat of the bath weld. Preferably, and since the thickness varies depending on the location, it is appropriate to fix by numerically controlled electron beam welding, but various other known methods, such as shrink fitting, screw fitting, and various manual methods of fixing, are suitable. can do. When replacing the cone 4 and journal 2, use the journal mounting part 2a.
The journal can be easily removed by drilling from the outside.

In the above embodiment, the journal part was attached to the body by providing a circular hole in the body and fitting the circular cross section provided in the journal mounting part, but as shown in FIG. 2 is integrally formed with a portion 2b corresponding to the journal attachment portion of the body 1, and after attaching the cone, the body is cast into a shape excluding the portion corresponding to the portion 2b, and is then welded 6 or the like. It may also be fixed. In this case as well, if the cone and journal wear out over time, it is possible to regenerate them by cutting off the fixed parts and installing new ones.

Effects of the Invention As described above, the present invention simplifies bit assembly, reduces the amount of welding, and can be applied not only to new construction, but also to repairs and refurbishment of wear caused by use over time, improving economic efficiency. is effective.

FIG. 3 is a side view showing the shape of a journal member according to another embodiment of the present invention.

1...Body 2...Journal 4...Cone 5...Protrusion 6...Welding part voltage 1 (a) (b)

Claims (1)

[Claims] A method of manufacturing a bit in which three cones are rotatably supported on three journals that stand diagonally toward the center line on the inner surface of the body, and the body except the journal part is integrally formed by casting. The three cones are held at predetermined mounting positions within the body, the journal is fitted into each of the above cones from the outside, each cone is pivotally supported by the journal, and each journal is fixed to the body. Characteristic bit manufacturing method.