JPS5936076B2 - boring bit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of a bit body joined to a string of pipes, comprising several rims or bit segments supporting freely rotatable a conical drilling element. Each drilling element relates to a bit for poling relatively deep holes, such as in rock of the Earth's crust, having a journal or hole forming part of the journal bearing.

Such a bit is known, for example, from US Pat. No. 3,307,645.

However, the present invention discloses a polling pin I of the above-mentioned type which in principle solves the problem of bearing seals and also allows for a much improved construction of known ball locking devices or retaining bearings. do.

To this end, the invention provides that the outer ring of the bearing system is in principle an element that is removably connected to said bit segment, the outer surface of said outer ring together with the inner surface of the drilling element being on one side of the bit. It forms a slit-like space in open communication with the external space and connected on the other side by several liquid transfer ducts which generate a relatively high pressure at least during operation, thus forming a closed end of the slit-like space and an opening. It is intended that a bearing seal be formed by the differential pressure prevailing in the space between the ends.

This method replaces known mechanical sealing devices such as backing rings with fluid seals, as long as the liquid is conveyed under pressure from the inside to the outside of the outer ring of the bearing through the pipe string during poling. This allows sealing to be performed without any misalignment on the other side of the slit-type seal and having little effect on the actual journal bearing.

Corresponding to this, for example, French Patent No. 10
No. 53319 can be mentioned, which uses a portion of the polling fluid as a coolant for plain bearings, so the fluid can only be pumped directly to the bearings through a duct system. Not yet.

The polling bit of the present invention has a duct system,
One of the ducts passes through the segment or part of the segment and the outer ring of the bearing and ends in a slit-like space;
A duct can be opened between the duct and a cavity or a chamber for containing liquid in the bit body.

With this device, polling fluid, for example mud water, flows along the pipe string to which the bit is fixed, enters the duct system through the chamber or cavity of the bit body, and then flows along the slit-like space at the open end of the space. It may leak to.

This effectively prevents fine cutting debris from entering the bearing system from outside the bit against the liquid flow.

In order to achieve a stable fixation of the excavation element in the bearing system, known holding ball bearings must be used, but in the present invention the support is provided around the journal of the excavation element and at the open end of the slit-like space. A slit-shaped space is provided in the middle and communicates with a circular duct in which a duct passing through the bit segment and the outer ring of the bearing is connected, and the rolling element is housed in the circular duct, so that the holding bearing is a journal bearing. It has features that allow it to form a relatively large diameter locking mechanism for the drilling element thereon and to form part of a fluid seal.

Furthermore, the average diameter of the retaining bearing should preferably be equal to the outer diameter of the outer ring of the journal bearing.

This makes it possible to fit rolling elements such as balls into the circular duct better than in the prior art, which particularly contributes to a stable fixation of the excavation element in the pit segment I.

Therefore, by improving the fluid seal and the ball or roller bearing fixing device, i.e., the holding bearing, the conventional bit with a mechanical seal, i.e., para-gimbling, on the way to the open end of the sulin I-shaped space is finely divided. The bits of this invention have a much longer service life than known bits, although the packing rings are quickly damaged by the heavy wear caused in this area by drilling dust.

The present invention will now be described with reference to the accompanying drawings.

The figure shows a fitting 3 connected to a pipe string (not shown).
Pit 51 mainly consists of a body 2 provided on the upper part.
0 shows a partial cross section.

Fluid is pumped through this string into the cavity or chamber 4, with some of the fluid going to duct 5.

This duct 5 is formed under the lower part of the body 2 and under a part 6 of the segment 7.

In this embodiment, the segment portion 6 is g-wedge shaped, as disclosed in Dutch Patent Application No. 7507355 of the present applicant.

This segment part 6 is fixed to the segment 7 with a fixing pin 8.

In the segment part 6 there is a second duct 9 communicating with said duct 5.

This duct 9 has a diameter to allow the introduction of balls or other rolling elements 10 and accommodates end joint pins 11 which capture the rolling elements 10 in a duct 12 associated with the tip of the duct 9.

This duct 9 is also formed in the outer ring 13 of the journal bearing, and the associated duct 12 is annular around the journal 15 of the journal bearing 14, partly in the digging element 1
6, and the other portion is formed outside the outer ring 13.

In this way, the rolling elements 10 such as balls are connected to the excavating element 16 and the outer ring 1.
Since it is fitted via the duct 9 into the circular duct Y 12 formed in accordance with 3, the retaining bearing is located around the maximum diameter of the digging element 16, effectively at a certain distance outside the actual journal bearing. (located at , it becomes a stable holding bearing.

According to the invention, the duct 12 is open and communicates with both the slit-like space 17 between the outside of the outer ring 13 and the inside part of the digging element 16 and the duct 90 .

There is an annular seal 18 in the slit-shaped space 17 at a distance from the holding bearing 10.degree. 12, which opens a part of the slit-shaped space 17 into the second space 19.

This second space 19 belongs to the second duct system and communicates with a space 20 filled with two rows of υ rolling elements 21 and 22 inside.

One of the rolling elements 21 is a tapered roller, and the other 22 is a cylindrical roller, but the rolling elements of this journal bearing are not limited to such rollers.

That is, the journal bearing may be a sliding bearing or a combination of a sliding bearing and a rolling bearing.

The rolling elements 21 and 220 raceways are formed inside the outer ring 13 and outside the neck or journal 15.

In this embodiment, the second duct system includes the slit-like second space 19 and the space 23 of the head of the journal 150.
and a chamber 24 adjacent to the space 23 and having a wall 25 made of flexible material.

This flexible wall 25 mainly serves as a diaphragm,
For this purpose, the hole 26 communicates with the space outside the bit.

Preferably, the chamber 24 and the hole 26 are provided in the bit segment 6.

In operation, the bit 1 is screwed onto a pipe string (not shown) which is rotated by a 1 drive.

The poling action on the earth's crust is performed by rotation and indentation.

At the same time, a pump (not shown) forces fluid, often mud, into the pipe, and most of this fluid flushes the poling excavation.

Fluid is thus forced into the surroundings from the rotating cutter during poling.

However, according to the invention, some of this fluid
Used to form seals.

That is, after the fluid has flowed through the duct 5 and along the duct 9 (therefore, the pin 11 allows the fluid to pass through the duct 9 and into the duct 1).
In some cases, vertical grooves are formed to allow water to flow into the water.

1.) It flows into the slit-like space 17 through the circular duct 12, and is pushed out of the bit from here.

This flow through is effected by the pressure in the chamber 4 communicating with the duct system 5, 9, 12 and the space 17, which is at a higher pressure than outside the bit as long as the pumping device is in operation.

The second duct system 19, 20, 23, 24 has a flexible wall 25 which is exposed to the pressure prevailing outside the bit.

By suitably selecting or shaping this wall 25, it is possible to press it in or move it within limits that are a function of the poling depth, so that this second duct system The pressure in a chamber filled with a medium, for example a lubricant, is likewise affected by this.

The invention is not limited to the embodiments described above, but it is possible to provide a duct system in which a fluid seal is provided between the rotating drilling element and the static IE part of the bearing or bit part in accordance with the technical idea of the invention. It also includes all structures in which such a transfer path is provided.

[Brief explanation of the drawing]

The figure is a partial cross-sectional view of one embodiment of the present invention, in which 1 is a polling bit, 2 is a bit body, 4 is a cavity, 5 is a duct, 6 is a segment portion, 7 is a bit segment, and 9 is a third bit. 2 ducts, 10 a ball, 12 a circular duct, 13 an outer ring, 14 a journal bearing, 15 a journal, 16 an excavation element, and 17 a slit-like space.

Claims (1)

[Claims] 1. Consisting of a bit body joined to a pipe string and having several rims or bit segments supporting freely rotatable conical digging elements, each digging element being supported by a journal bearing. In a polling bit having a journal or neck forming part of it, the outer ring of the journal bearing is adapted to be removably connected to the bit segment, and the outer surface of this outer ring is coupled to the inner surface of the digging element. One side is open to the external space of the bit, and the other side forms a slit-like space in which several liquid transfer ducts, each of which has a relatively high pressure during operation, are connected, thereby forming a closed end inside the slit-like space. A poling bit characterized in that a bearing seal is formed by a pressure difference balanced between the open end and the open end. 2. The polling bit according to claim 1, in which one of the ducts of the duct system A poling bit in which a second duct passes through a segment or a segment part and an outer ring of a bearing and ends in a slit-like space, and a second duct opens between said duct and a cavity or liquid receiving chamber in the bit body. The bit according to ranges 1 or 2, in which the slit-like space communicates with a circular duct surrounding the journal of the drilling element, the circular duct being located close to the open end of the slit-like space, and the bit segment and a duct that penetrates the outer ring of the bearing. 4. The bit according to claim 3, wherein the circular duct is partially formed inside the excavation element, and the duct is connected to a duct that penetrates the outer ring of the bearing. A part of the bit is formed outside the outer ring. 5. The bit according to any one of claims 1 to 3 and 4, comprising: a circular duct; and a straight duct connected to the duct. The duct is
The bearings formed in this way do not only constitute a retaining mechanism between the digging element and the journal bearing, but also act as part of the fluid seal. A bit characterized in that it also forms a part. 6. In any one of claims 2 to 5 and the bit according to claim 1, another duct system is formed in a part of the slit-like space starting at a point some distance from the holding bearing. Bit, characterized in that, after extending into the journal bearing itself, it continues into the pressure equalization chamber through the space between the journal of the drilling element and the bit segment. 7. A bit according to claim 6, characterized in that the pressure equalization chamber has a flexible wall and is located in a removable segment. 8. In the bit according to any one of claims 1 to 7, the two (reduct system) are mutually connected in the slit-like space by seal rings located at equal distances y from the holding bearing and the journal bearing. 9. The bit according to any one of claims 2 to 8 and the bit according to claim 1, wherein the opening duct system is capable of discharging so-called polling slurry or polling fluid relatively. a lubricant, characterized in that the second duct system, i.e. the system forming part of the journal bearing, is configured to hold and direct lubricant; -6 10. The bit according to any one of claims 1 to 9, characterized in that a part of the fluid duct system is located in the removable segment part. 11. In the bit according to any one of claims 1 to 10, the journal bearing has two rows of rolling elements, and the orbit of the rolling elements is on one side due to the outward direction of the shaft or journal. and the other side by the inner side of the outer ring. 12. In the bit according to any one of claims 1 to 11, the journal bearing is a rolling bearing. and a sliding bearing, wherein the raceways and surfaces of the bearing are formed on one side of the socket or journal and on the other side inside the outer ring. 13. A bit according to any one of claims 1 to 12, characterized in that the retaining bearing is located at a distance outwardly from the journal bearing itself. Any one in the range 1 to 11 - 1
2 or 13, wherein the average diameter of the holding bearing is equal to the outer diameter of the outer ring of the journal bearing. 15 Claims 1 to 13 One of the following and 1
In the bit described in 4. A bit characterized in that the average diameter of the journal bearing is smaller than the average diameter of the holding bearing.