JPS5918160Y2 - Rotating machine impeller device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a blade wheel device for a rotating machine, which is manufactured by installing moving blades in a T-shaped groove.

A blade wheel device for a rotating machine is manufactured by planting rotor blades around a rotating base.

To install rotor blades, grooves such as grooves are usually cut in the rotating base, and the blade roots of the rotor blade are fitted into these grooves.

There are two types of inlays.

There are two methods: inserting the blade root into a thick groove and tightening it with an appropriate means such as bolts, and the so-called "fitting method" in which a blade root of the same shape is tightly fitted into a groove of an appropriate shape.

By the way, the rotor blades of rotary machines such as axial flow compressors and axial flow turbines are designed to withstand thrust forces caused by centrifugal force, air pressure, steam pressure, etc., and to prevent vibrations. It must be devised.

Therefore, in the fitting method, the groove shape and the blade root shape are usually made to have the same shape as much as possible so that they fit perfectly together.

Grooves are formed as grooves in the axial direction or in the circumferential direction.In particular, when attempting to insert a blade root with the same shape in cross section into a groove that is formed long in the circumferential direction, it is difficult to precisely machine the same shape in advance. However, the higher the precision, the more difficult the insertion process becomes.

On the other hand, if the machining accuracy is intentionally compromised, that is, by creating a gap between the groove and the blade root in advance, the fixation of the rotor blade will deteriorate, and the rotor blade will not be able to handle the thrust force. vibrates,
The performance of the blade wheel is poor and the durability is also degraded.

Each of the two methods has its own merits and demerits, and it cannot be said that one is better in general.Due to various circumstances such as the technological tradition of the manufacturing factory and the type of rotating machinery, the appropriate method must be carefully considered in each case. A method is adopted.

The purpose of this invention is to eliminate the above-mentioned drawbacks of the fitting type blade wheel device, provide a blade wheel device for a rotating machine that has excellent fixation and vibration resistance, and is extremely easy to insert. This is an attempt to improve the so-called T-shaped groove shape, and the groove width is narrow in the middle part, and the middle part has a lower part and an upper part in which the groove width is wider on both sides in the radial direction. In a blade wheel device of a rotating machine in which a rotor blade with a blade root having the same shape as a groove with a cross section is inserted along the groove, the height width in the radial direction of the intermediate portion of the groove. If a is the height width in the radial direction of the corresponding part of the blade root that fits into the groove in the intermediate part, then a<b, and the groove continues to the lower side in the intermediate part of the groove. If the height width in the radial direction of the lower side part is C, and the height width in the radial direction of the corresponding part of the blade root that fits into this lower side part is d, then c>d, and the groove is A cylindrical elastic material is interposed between the bottom of the blade root at the corresponding part to be fitted and the bottom of the groove, and the cylindrical elastic material is interposed between the two to push the rotor blade upward. It is characterized in that the axial direction of the resilient material and the direction of the grooves intersect with each other.

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

In Figures 1 and 2, 1 is a rotor blade having a blade root 2, and 3 is a groove made in the rotating base 4 of the car body whose axial direction is the left and right direction in the paper, and whose cross section is so-called T-shaped. Because of this, it is generally called a T-shaped groove, but in this specification it will be called a square-shaped groove.

This groove consists of an intermediate portion 3a with a narrow groove width, and a lower side portion 3b and an upper side portion 3C with a wider width that continue on both sides of the intermediate portion 3a in the radial direction (in the vertical direction on the paper),
Therefore, the cross section shown in the figure is a square-shaped groove.

Further, this groove 3 is continuous in the circumferential direction (perpendicular to the paper surface at the illustrated cross-sectional position) and is a groove.

Now, let the height width in the radial direction of the middle part of this groove be a,
If b is the height width in the radial direction of the corresponding portion 2a of the blade root that fits into the groove in the intermediate portion, a<b, and
Let C be the height width in the radial direction of the lower part 3b following the intermediate part 3a of the groove 3, and the height width in the radial direction of the corresponding part 2b of the blade root 2 that fits into this lower part. If d, then the magnitude relationship is determined so that c>d.

The degree of this size need not be explained and is determined empirically, but I would like to state that it is possible to easily separate the two blades without forcibly displacing the blade root into the groove (without the two contacting each other). This is the extent to which relative displacement can be performed.

Between the bottom of the blade root 2 that fits into the groove 3 (e.g. 2d) and the bottom of the groove 3 (e.g. 31.), there is an elastic force between them so as to push the rotor blade upward. A cylindrical elastic material 5 is interposed to cause the cylindrical elastic material 5 to move in the axial direction of the cylindrical elastic material (in the left-right direction on the paper in FIG. 2, and perpendicular to the paper in FIG. 3).
and the direction of the groove 3 intersect with each other.

As the resilient material, preferably a roll pin, particularly preferably a cylindrical split pin 5 is used.

As clearly shown in FIG. 3, when the direction of the grooves 3 is the circumferential direction, the roll pin 5 is placed in the axial direction.

6 is a notch provided at the bottom of the rotor blade for stably positioning the roll pin 5 with respect to the rotor blade.

The split pin form of the roll pin 5 can be devised in various ways as shown in FIG.

In the above embodiment, the grooves continue in the circumferential direction of the vehicle body 4, but the grooves may be provided in the axial direction.

In the embodiment shown in FIG. 3, although not shown, the vehicle body 4
The rotor blade 1 is inserted through a relatively large hole drilled in the radial direction in a part of the rotor blade 1.
, and insert the blade root 2 into the groove 3 in the circumferential direction.At this time, fit the cotter pin 5 into the notch 6, and press the entire rotor blade from above to hold it down while moving forward. By doing so, the entire moving blade can be easily fitted to the rear while falling onto the cotter pin 5 with a relatively weak holding force.

When you stop pressing from above, as shown in Figure 2,
In the rotor blade, the upper surface of the shoulder of the lower part 2b of the blade root 2 abuts against the upper end surface of the lower part 3b of the groove 3, and is pushed upward by the resilient material 5 and stopped at a fixed position.

The same procedure is used to remove the rotor blades from the vehicle body for replacement.

As mentioned above, in the present invention, the dimensional accuracy of the blade roots and grooves is relaxed by setting the dimensions, which not only reduces processing costs but also makes sliding when fitting the rotor blades extremely easy.

It should be noted that the fixedness of the rotor blade of this invention, which is pushed up by the explosive material, is not as strong as that of tightly fitted bolts or wedges. Since the large centrifugal force acting on the rotor blades is added to the elastic force, a fixing force equivalent to bolt tightening can be obtained, and the fixing force that is actually necessary is to tighten the bolts more than necessary to avoid loosening. Rather, by carefully determining the elastic modulus of the elastic material for the combined force of centrifugal force, elastic force, and centripetal force applied to the rotor blade, it is possible to tolerate intense impact while allowing minute amplitude and long-period vibration. As for vibrations, it is possible to create a virtually vibration-free system, which results in even better results in terms of vibration prevention.
-It has the effect of killing two birds.

If the blades have a tight fitting structure (it is virtually impossible to contact each other on a continuous surface, and in reality it will be a multi-point contact), vibrations, misalignment, etc. may cause the rotor blades to loosen during long rotations. However, the present invention has excellent stability in fixed position over a long period of time, and therefore the gap e between the casing 7 and the tip 6 of the rotor blade 1 is reduced.
It has the effect of killing two birds with one stone in that it remains constant over a long period of time, and it also has the effect of killing two or three birds with one stone in that it is extremely easy to insert, assemble, remove and replace.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a specific example of the cylindrical elastic material of the present invention;
FIG. 2 is a side sectional view showing one embodiment of the present invention, and FIG. 3 is a front view showing an assembled state.

Claims (1)

[Scope of utility model registration request] The rotor blade has a blade root whose cross section is the same shape as the square-shaped groove, which is composed of an intermediate part with a narrow groove width, and a lower part and an upper part with a wide groove that continues in the radial direction on both sides of the intermediate part. In a blade wheel device of a rotating machine that is inserted and fitted along a groove, the height width in the radial direction of the intermediate portion of the groove is a,
If b is the height width in the radial direction of the corresponding part of the blade root that fits into the groove in the middle part, then a<b, and also, If the height width in the radial direction is C, and the height width in the radial direction of the corresponding part of the blade root that fits into this lower side part is d, then c>d, and the corresponding part that fits into the groove A cylindrical elastic material is interposed between the bottom of the blade root and the bottom of the groove of the part, and the elastic material is interposed between the two so as to push the rotor blade upward.
A blade wheel device for a rotating machine, characterized in that the axial direction of the cylindrical elastic material and the direction of the grooves intersect.