JPS59192405A - Internal boring device for bent pipe - Google Patents

Abstract

PURPOSE:To make accurate boring attainable in a short time, by building in both of a tool turning drive mechanism and a center rest inside a boring bar having the same curvature as that of a workpiece, in case of an internal boring device for a bent pipe carrying a single radius form. CONSTITUTION:In time of internal boring for a workpiece 1 being a flange elbow type bent pipe of a steam inlet pipe or the like for a steam turbine, the workpiece 1 is locked upward to a jig 3 having a tilting angle of 45 deg. in consideration of exhaustibility in chipes out of the workpiece. On the other hand, a boring bar 4 is set down to an elbow form having the same curvature as the workpiece 1 and locked to a support arm 5 which is solidly provided with a slide base 6 to be slidably displaced by an adjust screw 7 in order to make a radius center adjustable according to curvature of the workpiece 1 and locked to a face plate 8 being free of rotation around an X-axis. And, the boring bar 4 is provided with a center rest device 15 inclusive of both of a boring head 10 supporting a tool 2 at its tip and a steel ball 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for processing the inner surface of a curved pipe having a single-R shape, such as a steam inlet pipe of a steam turbine.

[Technical background of the invention and its problems]

The bent pipe at the high-pressure side inlet of a steam turbine for a thermal power plant is made of thick special steel and is welded, cast, or
Although it is formed by forging, etc., in many cases, the inner surface is rough and has waves and undulations, so some kind of secondary processing is required. In general, it is necessary to rely on simple tools such as hand grinders, which can only remove scale and small irregularities on the surface, and high quality cannot be expected.

Recently, as the development of supercritical pressure steam turbines progresses, it has become desirable for the bent pipe to have a flange elbow shape with a straight part and a flange part forged integrally at the end for strength and quality reasons. In this case, the inner surface condition of the material becomes even worse, and there is a growing demand for higher accuracy and efficiency in inner surface processing.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a processing device that can perform precise poling processing in a short time by cutting the inner surface of a flange elbow-shaped bent pipe. .

[Summary of the invention]

In order to achieve the above object, the present invention provides a boring bar that has the same curvature as a bent pipe of a workpiece fixed on a jig and that can be inserted into this bent pipe, and a boring bar that supports this boring bar and that supports the bent pipe. A face plate that rotates along the pipe axis, a hydraulic motor installed inside this boring bar, a boring head driven by this hydraulic motor and attached to the tip of the boring bar, and a bent pipe attached to this boring head. The boring head is characterized by a tool for cutting the inner surface of the pipe, and a steady rest device that pivotally supports the boring head and comes into contact with the inner surface of the bent pipe.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to Figures 1 to 4. Considering the natural evacuation of chips, the workpiece (1) is machined with a jig (
3) Fix it facing upward. The boring bar (4) has a 9Cf' elbow shape with the same curvature as the workpiece (1), and is fixed at right angles to the support arm (5) with a flange. The support arm (5) has a slide base (6) and an adjusting edge (7) to adjust the R center according to the curvature of the workpiece (1), and is attached to the face plate (8) at the desired position. Can be fixed. In addition, the support arm (5) has a hollow structure, and inside it is used as a boring bar (41"-L%) for controlling parts such as hydraulic hoses.

The face plate (8) is integrated with a rotating shaft of a spindle head (not shown), and the turning movement of this rotating shaft around the central axis X serves as the so-called feeding function of the boring bar (4). On the text board (8), on the opposite side of the support arm (5) with respect to the X axis, a balance weight (9) is attached.
), the balance is adjusted to help smooth turns.

As shown in Fig. 3, a disk-shaped boring head 10) with a shaft is provided at the tip of the boring bar (4), and a tool (2) is attached.
). The shaft of the polling rod 00) is supported by a bearing 01), and its shaft end is connected to a hydraulic motor 00 by a universal joint (13) to transmit rotational force. The hydraulic motor circle is fixed to the connector I with a flange and is housed in a hollow boring bar (4). Next, a steady rest device 0■ is installed to prevent vibration and deflection due to cutting, which has another important function that helps stable boring processing.

Steady rest device θ is boring head 0υ and connector 0
The piston rods located at three locations on the circumference (the piston rods protrude radially and come into contact with the machining surface to firmly support the boring bar (4). 9
Since the contact type steel ball αη is built into the tip of the piston rod 06), smooth contact is possible. The piston rod α0 is operated by hydraulic pressure or air fluid, and the fluid that serves as the driving source is connected to the inside of the connector 04) and the steady rest by piping a hose through the boring bar (4) to the end of the connector α4). It is guided to the cylinder part 0 through the flow path formed in the device (1).A multi-groove labyrinth seal α9 is used between the steady rest device θ and the boring head 00 to prevent foreign matter from entering the bearing part. prevent.

Next, the effect will be explained.

Take out the machining centers of the workpiece (1) and the boring bar (4), align their center axes on the same circumference, and align the R center of this center line with the center axis X of the turning axis of the face plate (8). In the matching setup state, the boring head 00) with the tool (2) set to the machining diameter is driven by the hydraulic motor (+2). Next, the face plate (8) is rotated by the drive from the spindle head, and the boring bar (4) is sent to the back of the machined hole. At that time, confirm that the steady rest device 0!19 enters the hole, turn on the hydraulic pressure or air pressure, and extend the piston rod 06) on three sides to support the boring bar (4) to suppress vibration and deflection and ensure smooth operation. Perform processing. Machining ends at a position rotated 90 degrees from the start of machining, and returns to the starting position.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings; for example, the method of placing the workpiece horizontally, or the method of forcibly discharging chips using cutting oil, supply air, etc. It is also possible. In addition, it can be applied not only to cutting but also to grinding using a whetstone, and even when the tool is fixed without rotating.
Therefore, it can also be applied to shaper machining with only turning movements.

〔Effect of the invention〕

As explained above, according to the present invention, cutting conditions equivalent to those for straight hole machining can be obtained by compactly incorporating the tool rotation drive mechanism and steady rest device into a boring bar with the same curvature as the workpiece. It is possible to obtain a curved tube inner surface processing device with good performance that enables precise processing in a short time even on a workpiece with a large machining allowance.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the curved pipe inner surface machining device of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a sectional view showing the structure inside the tip of a boring bar, FIG. 4 is a sectional view taken along line A--A in FIG. 3. 1. Workpiece (bent pipe) 2. Tool 3. Jig 4. Boring bar 8. Face plate 10.
・Boring head 12...Yurazu motor 15・
... Steady Rest Device Agent Patent Attorney Noriyuki Chika (
(1 person) 1st cause 2nd cause 3rd cause

Claims (1)

[Claims] A boring bar that has the same curvature as the bent pipe of the workpiece fixed on the jig and can be inserted into the bent pipe, and a face plate that supports the boring bar and rotates along the pipe axis of the bent pipe. , an oil tank motor provided inside this boring bar, a boring head driven by this hydraulic motor and attached to the tip of the boring bar,
A tool that is attached to this boring head and cuts the inner surface of the curved pipe, and a tool that supports this boring head (
A device for processing the inner surface of a bent tube, which consists of a steady rest device that comes into contact with the inner surface of the bent tube.