JPS6346540Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a mechanical seal used as an upper seal of a turbo drill.

In conventional turbo drills that use pressurized fluid to rotate a bit at high speed while drilling underground, a rotating shaft is supported by a radial bearing and a thrust bearing. In addition, an oil reservoir filled with lubricating oil is provided inside the turbo drill body, and this oil reservoir supplies lubricating oil to each of the above-mentioned bearings. Above the oil reservoir, the turbine side and the oil reservoir are separated. A mechanical seal shown in FIG. 5 is used as the upper seal. This mechanical seal is a chamber c between the turbo drill body a and the rotating shaft b, into which the mud flows.
and an oil reservoir d, and a seal ring f and a drive collar g, which rotate together with a rotating shaft b, are housed in the piston e, and a drive collar g is housed in the drive collar g. By pressing the seal ring f and drive collar g against the piston e-side seals i and j by a compression spring h, a seal is established between the rotating shaft b and the piston e.

Problems that the invention aims to solve In addition, the piston e pressurizes the oil reservoir d by receiving the pressure from the mat from the chamber c side, and stops when the pressure in the oil reservoir d is balanced, but the piston e is pumped from the ground to the chamber c. Since there is a pulsation in the mat being moved, this pulsation causes a force to act on the drive collar g in the piston e to push it toward the reservoir d. An O-ring k is provided between the drive collar g and the rotating shaft b, and the sliding resistance of this O-ring k prevents the seal ring f from moving for a short period of time, but once it starts moving, the
Since the ring k acts as a resistance and the compression spring h opposes the force pushing back the seal ring f, the seal surface i opens due to the pulsating pressure of the mud, causing the mud to flow into the oil reservoir d.

Means and Effects for Solving Problems This invention was made for the purpose of improving such problems, and it includes a seal ring on the side in contact with the inner surface of the turbo drill body, a piston on the side in contact with the rotating shaft, Further, there is provided a mechanical seal for a turbo drill which has a structure in which back pressure is applied to the seal ring so that the seal part is difficult to open due to the pulsation of the mud, thereby preventing mud from getting mixed into the oil reservoir. It is.

Embodiment An embodiment of this invention will be described in detail with reference to an embodiment shown in FIG.
The mud flowing in from this inlet 2 drives a turbine 3.

The rotation of the turbine 3 is controlled by a bearing 4 in the center of the main body 1.
The power is transmitted to the bit 6 provided at the tip of the rotating shaft 5 through the rotating shaft 5 supported by the rotary shaft 5, and the rotation of the bit 6 serves for drilling underground, and the mud that drives the turbine 3 is It reaches the bit 6 through a passage 5a formed in the rotating shaft 5, and is ejected from an ejection hole 6a opened in the bit 6.
Together with the earth and sand excavated by the bit 6, it ascends the annulus 8 formed between the well 7 and the outer periphery of the main body 1, and is discharged to the ground.

On the other hand, an oil reservoir 11 divided by a lower seal 9 and an upper seal 10 is provided between the rotating shaft 5 and the main body 1.
The oil sealed in the bearing 4 lubricates the bearing 4, and the upper seal 10 is equipped with a mechanical seal 12 shown in FIG. The mechanical seal 12 has a piston 13 provided so as to surround the rotating shaft 5, and a drive collar 14 divided into two parts between the inner circumferential surface of the main body 1. An O-ring 15 is interposed between each drive collar 14 and the inner peripheral surface of the main body 1 to ensure liquid tightness between the two, and a compression spring 16 is interposed between each drive collar 14. This compression spring 16 causes the drive collar 14 on the oil reservoir 11 side to
The seal ring 17 attached to the piston 13
The ring member 13a is pressed against a sealing surface 18 of a ring member 13a fixed to one end of the ring member 13a. A recessed step 14a is formed at the end of the drive collar 14 on the side of the upper chamber 19 into which the mats flow, and one end of the seal ring 20 is slidably fitted into this recessed step 14a. The seal ring 20 has a substantially V-shaped cross section, and a plurality of spring chambers 20a are formed in the circumferential direction at the end fitted into the recessed step 14a. A preload is applied to the seal ring 20 by the spring 21, and the inner peripheral surface of the recessed step 14a of the drive collar 14 is a convex spherical surface 14b as shown in FIG.
An annular groove 14c is formed at the top of this convex spherical surface 14b.

An O-ring 22 is accommodated in the annular groove 14c and performs a seal between the drive collar 14 and the seal ring 20, and also causes conical eccentric movement in the rotating shaft 5 due to play in the bearing 4 or play due to wear. When this occurs, the convex spherical surface 14b of the inner peripheral surface of the recessed step portion 14a prevents the drive collar 14 and the seal ring 20 from interfering with each other.

The same effect can be obtained even if the convex spherical surface 14b is provided on the seal ring 20 side as shown in FIG. 4, and an annular groove 20c for accommodating the O-ring 22 is provided at the top thereof.

On the other hand, the seal ring 20 on the upper chamber 19 side is pressed against the seal surface 23 of the ring member 13b fixed to the other end of the piston 13 by the action of the compression springs 16 and 21, and the seal ring 20 is in pressure contact with the seal surface 23 of the ring member 13b fixed to the other end of the piston 13.
The pressure inside the upper chamber 19 is received as back pressure.

Effects of the invention This invention has been described in detail above, so that the seal ring 20 on the side of the upper chamber 19 into which the mud flows is formed by the compression spring 16 that biases the drive collar 14 and the compression spring 21 that biases the seal ring 20. At the same time as it comes into pressure contact with the sealing surface 23 on the piston 13 side,
Since the pressure of the mat in the upper chamber 19 is used as back pressure, the seal ring 20
follows closely and can reliably prevent the sealing surface 23 from opening, and even if the sealing surface 23
Even when opened, the mat is on the outside with respect to the sealing surface, so that intrusion into the oil reservoir chamber 11 due to centrifugal force can be reduced. In addition, one of the sliding contact parts of the drive collar 14 and the seal ring 20 is pre-coated with a convex spherical surface 14.
By setting b, it is also possible to prevent interference between the two even if conical eccentric movement occurs in the rotating shaft 5.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a turbo drill that is an embodiment of this invention, Fig. 2 is an enlarged explanatory view of the mechanical seal portion, Figs. 3 and 4 are enlarged explanatory views of the drive collar and seal ring portion, FIG. 5 is an explanatory diagram showing a conventional mechanical seal. 1 is a turbo drill body, 3 is a turbine, 12 is a mechanical seal, 13 is a piston, 14 is a drive collar, 16 and 21 are compression springs, 19 is an upper chamber, 20 is a seal ring, and 23 is a sealing surface.

Claims (1)

[Scope of utility model registration request] A piston 13 and a mechanical seal 12 are provided between an oil reservoir 11 provided in the turbo drill body 1 and an upper chamber 19 into which a part of the mud that has exited the turbine 3 flows. on the side, and mechanical seal 1
2 drive collars 14 are disposed on the inner peripheral side of the main body 1, and a seal ring 20 preloaded by a compression spring 21 is provided on the end face of the drive collar 14 on the upper chamber 19 side. The compression spring 16 that biases the engine and the compression spring 21 that applies the preload are brought into pressure contact with the sealing surface 23 on the piston 13 side, and the mud pressure in the upper chamber 19 is applied to the seal ring 20 as back pressure. Mechanical seal for drill.