JPS64467Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mechanical seal used for the lower seal of a turbo drill.

Conventional turbo drills, in which the bit is rotated by a turbine driven by fluid pressure to drill holes in rocks, etc., have a radial bearing that supports the rotating shaft within the main body, and a thrust force that is applied to the rotating shaft by differential fluid pressure. Each thrust bearing is provided with a lubricating oil sealed between an upper seal provided at the upper part of the main body and a lower seal provided at the lower part of the main body. Further, a mechanical seal as shown in FIG. 1 is used as the lower seal. As shown in Fig. 1, the above mechanical seal is provided with a seal ring e between a floating seal b attached to the main body a side and a drive collar d provided on the rotating shaft c side. The sealing is performed by the sliding surface f of the seal b.

However, the turbo drill frequently performs bending excavation, and during bending excavation, the rotating shaft c deforms, and as shown in Figure 2, the center o of the rotating shaft c becomes eccentric with respect to the center o of the main body a. Due to the rotation, the seal ring e provided on the rotation axis c side moves conically eccentrically as shown by the arrow g. For this reason, in the conventional mechanical seal in which the floating seal b and the seal ring e are in plane contact, the seal ring e cannot follow the movement, causing oil leakage.

This idea was made to improve this problem, and the shape of the contact area between the drive collar and seal ring has been improved so that the seal ring can easily follow conical eccentric movement due to deformation of the rotating shaft. The present invention provides a mechanical seal for a turbo drill that provides a good sealing effect even during bending drilling.

This invention will be described in detail below with reference to an embodiment shown in FIG. 3 and subsequent figures. FIG. 3 is an overall view of the turbo drill, in which a mud inlet 2 is opened at one end of the main body 1, and a turbine 3 is rotated through this inlet 2. The rotation of the turbine 3 is transmitted to a rotating shaft 6 supported within the main body 1 via a radial bearing 4 and a thrust bearing 5. The rotating shaft 6 is the main body 1
The bit 7 attached to the tip of the rotating shaft 6 is used for drilling into the rock, and the soil excavated by the bit 7 passes through the passage 6a in the rotating shaft 6 to the bit 7. spout hole 7
The mud ejected from a is transported to the ground through an annulus 9 formed between the outer periphery of the main body 1 and the well 8. Further, an upper seal 10 and a lower seal 11 are provided in the main body 1, and the bearings 4 and 5 are lubricated by the lubricating oil sealed between these seals 10 and 11. The following mechanical seals are used. In the lower seal 11, a floating seal 13 is fluid-tightly attached to a sleeve 12 fixed to the inner circumference of the main body 1, and a seal surface 14a of a seal ring 14 is in sliding contact with one end of the floating seal 13. The protrusion 13a is provided in an annular manner. Further, the seal ring 14 is supported by a drive collar 15 attached to the rotating shaft 6 side. The drive collar 15 is fitted onto the outer peripheral surface of a sleeve 17 that rotates together with the rotating shaft 6, and is configured to be able to slide in the axial direction of the sleeve 17.
A retainer 18 is provided behind the drive collar 15 and is fixed to the sleeve 17. This retainer 18 is provided with a plurality of pin holes 18a. These pin holes 18a have a small diameter on the opening side, and this small diameter portion 18b makes the pin holes 18a
By supporting the intermediate portion of the drive pin 24 inserted therein, the distal end side of the drive pin 24 can freely move around the small diameter portion 18b as a fulcrum, and the distal end of each drive pin 24 is , is fitted into a recessed hole 15a formed in the end face of the drive collar 15, and the drive collar 15 is urged toward the seal ring 14 by a compression spring 19. The drive collar 15 has a substantially L-shaped cross section, and the end surface of the large diameter portion 15b is formed with a convex spherical surface 15c having a radius R centered on a point o'' provided on the center of the rotating shaft 6, Above points
The seal ring 14 is in sliding contact with the end surface of the seal ring 14, which is formed into a concave spherical surface 14c having a radius R' centered at o''.
Further, the small diameter portion 15d of the drive collar 15 is inserted into the annular recess 14b of the seal ring 14, and the seal ring 1 is located deep inside the annular recess 14b.
4 and the sleeve 17 is housed therein.

In addition, the seal ring 14 and drive collar 15
The concave spherical surface 14c and the convex spherical surface 15c provided on the seal ring 14 side may be a convex spherical surface, and the drive collar 15 side may be a concave spherical surface.

As described in detail above, this device has an end face of the seal ring 14 that makes sliding contact with the floating seal 13 provided on the main body 1 side for sealing, and an end face of the large diameter portion 15b of the drive collar 15 that makes sliding contact with this end face. Since the uneven spherical surfaces 14c and 15c are in close contact with each other, even if the rotary shaft 6 is deformed and performs conical eccentric movement during bending excavation, the uneven spherical surfaces 14c and 15
c absorbs this and does not transmit it to the seal ring 14 side, so the seal ring 14 always follows the floating seal 13 to perform sealing. As a result, even if the rotary shaft 6 is deformed and performs conical eccentric movement during bending excavation, there is no risk of the sealing effect being impaired, and the drive pin 24 that transmits the rotation of the rotary shaft 6 to the drive collar 15 is retained. 1
8, the movement of the drive collar 15 is not restricted by the degree of freedom of the drive pin 24, which further improves the followability of the seal ring 14. You can also do it.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a conventional mechanical seal, FIG. 3 is a sectional view of a turbo drill showing an embodiment of this invention, and FIG. 4 is an enlarged view of the lower seal. 1 is the turbo drill body, 4 is the radial bearing, 5 is the thrust bearing, 6 is the rotating shaft, 10
11 is an upper seal, 11 is a lower seal, 13 is a floating seal, 14 is a seal ring, 14b is an annular recess, 14c is a concave spherical surface, 15 is a drive collar, 15b is a large diameter portion, 15c is a convex spherical surface, 15d is a small diameter portion , 18 is the retainer, 22 is the o-ring, 24
is the drive pin.

Claims (1)

[Scope of utility model registration request] A rotating shaft 6 provided within the turbo drill body 1
is rotatably supported by a radial bearing 4 and a thrust bearing 5, and an upper seal 10 and a lower seal 11 are provided at the upper and lower parts of the bearings 4 and 5.
In the case where lubricating oil is sealed between the lower seal 11 and the floating seal 13 provided on the main body 1 side and the floating seal 13 provided on the rotating shaft 6 side, sealing is achieved by slidingly contacting the floating seal 13. A seal ring 14 and an annular recess 1 formed at the end of the seal ring 14 opposite to the sealing surface.
Drive collar 1 in which small diameter portion 15d fits into 4b
5 and a retainer 18 that transmits the rotation of the rotating shaft 6 to the drive collar 15 via the drive pin 24, and the annular recess 14 of the seal ring 14.
An o-ring 22 for sealing between the seal ring 14 and the sleeve 17 is interposed in b,
Concave and convex spherical surfaces 14c and 15c are formed on the end surface of the large diameter portion 15b of the drive collar 15, which is in contact with the drive collar 15 side end surface of the seal ring 14, and the drive pin 24 is swingably supported on the retainer 18. Mechanical seal for turbo drill.