JP2004162766A - Flange coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability of a flange coupling. <P>SOLUTION: This flange coupling has a first coupling member 1a having a flange part 30a and a second coupling member 1b having a flange part 30b. A pressure receiving member 6 is held in the second coupling member. An end part of an upper side shaft 2 in which the first coupling is fitted has a tapered shape, and a tapered part 7 which coincides with the tapered shape is formed in the pressure receiving member. High hardness treatment is applied to an end part 8 of the upper side shaft. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flange coupling, and more particularly to a flange coupling suitable for fastening a large rotating shaft such as a nuclear pump.
[0002]
[Prior art]
An example of a conventional flange coupling is described in Patent Document 1. The coupling described in this publication is used for a reactor recirculation pump, and connects a motor shaft and a shaft of a vertical pump disposed below a vertical motor. The fit between the motor shaft and the flange member is a clearance fit, and the motor shaft and the flange member are relatively movable in the axial direction. The driving torque is transmitted using a sliding key. The pump shaft and the flange member are rigidly connected by bolts.
[0003]
During assembly, the pump shaft and the flange member are lowered by their own weight, and a gap of 2 to 3 mm is formed in the vertical direction between the spacer plug fixed to the flange member and the motor shaft. During operation, an upward axial load acts on the pump shaft to raise the pump shaft, so that the lower end of the motor shaft contacts the spacer plug. Thereby, the axial load of the pump shaft is transmitted to the motor shaft. The axial load transmitted to the motor shaft is supported by bearings of the motor shaft.
[Patent Document 1]
JP-A-5-18468 (FIG. 3)
[0004]
[Problems to be solved by the invention]
In the coupling described in the above publication, since there is a radial gap between the motor shaft and the outer cylinder cover of the coupling, the position of the outer cylinder cover may not be concentric or inclined with respect to the motor shaft. Also, when the outer cylinder cover is inclined with respect to the motor shaft, the contact surface receiving the axial load may come into contact with one side, resulting in excessive local stress or plastic deformation. This set causes an increase in misalignment and angular misalignment. Furthermore, the axial load of the pump shaft acts as a bending moment on the coupling, and appears as a set at the end of the slide contact portion or a galling at the time of movement in the axial direction, which may increase the misalignment or angular misalignment. Since misalignment or angular misalignment leads to an increase in shaft vibration, it is necessary to spend a great deal of effort to avoid this.
[0005]
The present invention has been made in view of the above-mentioned disadvantages of the related art, and has as its object to improve the reliability of a flange coupling used in a nuclear pump or the like.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a flange coupling includes a first coupling member coupled to a first shaft and a second coupling member coupled to a second shaft. The first feature of this configuration is that a pressure receiving member that is held by the second coupling member and that is in contact with the end of the first shaft is a tapered surface, a spherical surface, or a ring-shaped projection. It is in.
[0007]
The second feature is that a ring held by the first shaft and having an outer diameter larger than the outer diameter of the mounting portion of the first shaft and a ring held by the second coupling member and applied to the ring. And a pressure receiving member that comes into contact with the pressure receiving member. A third feature is that a pressure receiving member that can contact both the first shaft and the twenty-first coupling member is provided, and a working radius of a load applied from the first shaft to the pressure receiving member and a second cup. The difference is that the radius of the load from the ring member is different.
[0008]
In the above feature, it is preferable that the first flange member and the first shaft can be relatively moved in the axial direction using the first slide key, and the key groove in which the first slide key fits is formed. It is desirable for the first flange member to be smaller than the gap between the key and the key groove in the first sliding key portion.
[0009]
Further, at least one of a surface where the pressure receiving member contacts the first shaft and a surface where the first shaft contacts the pressure receiving member may be locally cured, and the pressure receiving member is fixed to the first shaft. The hardness of the surface of the lever receiving member opposite to the fixed side may be higher than other portions, and the pressure receiving member may be movable in the axial direction.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, several embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of one embodiment of the flange coupling according to the present invention. The flange coupling has a first coupling member 1a fitted to the upper shaft 2 and a second coupling member 1b fitted to the lower shaft, and the flange of each coupling member 1a, 1b. At the parts 30a and 30b, the bolts 21 and the nuts 22 are used to fasten the parts.
[0011]
The upper shaft 2 is fitted to the coupling member 1a while forming a gap 3 in the radial direction, and the upper shaft 2 and the coupling member 1a are relatively movable in the axial direction. A keyway 13 for the sliding key 4 for preventing the first coupling member 1a from moving in the circumferential direction with respect to the upper shaft 2 is formed on the outer peripheral portion of the upper shaft 2. Similarly, a key groove 5 is formed on the inner peripheral side of the first coupling member 1a so as to correspond to the position of the slide key 4. The key 4 is fixed in the groove 13.
[0012]
Inside the second coupling member 1b, a spacer plug (pressure receiving member) 6 having one surface in contact with the upper shaft 2 and the other surface in contact with approximately two coupling members 1b is held. The spacer plug 6 has a recess 41 at the center, and the peripheral edge 7 of the recess has an inclined tapered structure. The tapered shape of the peripheral portion 7 is formed so as to match the shape of the chamfered portion 2 a formed at the end of the upper shaft 2. Since the load of the upper shaft 2 is applied to the peripheral portion 7 of the spacer plug 6 from the chamfered portion 2a of the upper shaft 2, the peripheral portion 7 becomes a pressure receiving surface.
[0013]
The operation and function of the thus configured flange coupling of this embodiment will be described below. A driving torque generated by a driving source (not shown) is transmitted to the coupling member 1a via a sliding key 4 fixed to the upper shaft 2. At the same time, the axial load related to the upper shaft 2 is transmitted to the pressure receiving surface 7 of the spacer plug 6 held by the coupling member 1b. In this embodiment, since the pressure receiving surface 7 is tapered, when an axial load is generated, an aligning force is generated in which the center of the upper shaft 2 moves to the center of the spacer plug 6, and the upper shaft 2 and the coupling member 1a are generated. And reduce misalignment.
[0014]
Assuming that the inclination angle of the tapered surface 7 from the direction perpendicular to the axis is θ, if the inclination angle θ is close to 90 °, the surface pressure of the pressure receiving surface 7 becomes extremely large. In this case, the pressure receiving surface 7 is likely to be set. In order to improve maintainability, the vertical shaft and the coupling member 1b are lowered by their own weight when there is no axial load in the vertical shaft. That is, assuming that the axial load is F, the friction coefficient of the pressure receiving surface 7 is μ, and the own weight of the lower shaft 20 is m, each value is set so that the relationship of (Equation 1) is established.
[0015]
θ ≦ arctan (m / μF) (Equation 1)
By the way, when the axial center between the coupling member 1a and the upper shaft 2 is misaligned, a pressure receiving surface 7 for receiving an axial load and a slide contact portion where the upper shaft 2 faces the end of the coupling member 1a. The upper end 9 has a one-sided contact. Thereby, a large contact stress is locally generated. Therefore, the shaft end 8 of the upper shaft 2 and the upper end 9 of the slide contact portion are locally cured. For this hardening treatment, carburizing quenching, nitriding treatment or the like is used. By this hardening treatment, even if a partial contact occurs on the pressure receiving surface 7 of the axial load or the upper end portion 9 of the slide contact portion, set hardly occurs, and the misalignment and the angular misalignment can be reduced.
[0016]
Further, the inner diameter side of the end of the coupling member 1a opposite to the fastening portion with the coupling member 1b was formed in an arc shape. Due to this arc shape, a portion 30c is formed in the coupling member 1a to avoid contact with the upper shaft 2 by a distance d1 in the axial direction and by a distance d2 in the radial direction. The size of the distances d1 and d2 is set to 3% or more (d1, d2 ≧ 0.03D) of the diameter D of the upper shaft 2. When the upper shaft 2 moves relatively to the coupling member 1a, galling is less likely to occur at the upper end portions 30c and 9 of the slide contact portions, and the misalignment and the angular misalignment can be reduced. The shape of the avoiding portion 30c may be a tapered shape like a chamfer or a straight line.
[0017]
The radial gap 12 between the sliding key 4 and the keyway 5 is smaller than the radial gap 3 between the coupling member 1a and the upper shaft 2. The radial gap 12 between the sliding key 4 and the key groove 5 of the coupling member 1a is made as small as possible within a range where the upper shaft 2 and the coupling member 1 can move smoothly in the axial direction. In the present embodiment, the radial gap 12 is set to 25 μm or less. Since the radial gap 12 is small, misalignment and angular misalignment of the upper shaft 2 with respect to the coupling member 1a can be suppressed. The contact area between the sliding key 4 and the key groove 5 is smaller than the contact area between the upper shaft 2 and the coupling member 1a. Therefore, even if the radial gap 12 is reduced, there is almost no possibility that the smooth movement of the upper shaft 2 in the axial direction is hindered.
[0018]
In the above embodiment, the slide key 4 is fixed to the shaft, but the slide key 4 is fixed to the coupling member 1a so that a radial gap is formed between the slide key 4 and the key groove 13 of the shaft. Is also good. In this embodiment, both the pressure receiving surfaces 7 of the upper shaft 2 and the spacer plug 6 have a tapered shape, but only one of the pressure receiving surfaces of the upper shaft 2 and the spacer plug 6 may have a tapered shape. Further, although the spacer plug 6 is formed separately from the coupling member 1a, the coupling member 1b may be brought into direct contact with the upper shaft 2 without using the spacer plug 6. Although the upper shaft 2 is locally cured, the inner peripheral surface of the spacer plug 6 on the side opposite to the pressure receiving surface 7 of the spacer plug 6 and the coupling portion of the coupling member 1a with the coupling member 1b is cured. You may.
[0019]
FIG. 2 shows another embodiment of the flange coupling according to the present invention. This embodiment is different from the above embodiment in that a pressure receiving member 10 having a high hardness spherical shape is bonded or fixed to the lower end of the upper shaft 2, and a spherical surface 7a in which the high hardness pressure receiving member 10 is recessed is formed. That is, the pressure-receiving member 6a is supported by the pressure-receiving member 6a. Thereby, the sag of the upper shaft 2 due to the axial load and the misalignment of the coupling member 1a with respect to the upper shaft 2 are reduced. Since the contact surface is unlikely to have one-sided contact, sag due to local stress can be prevented. In this embodiment, the pressure receiving member 10 as a separate member is provided at the lower end of the upper shaft 2, but the same effect can be obtained even if the lower end surface of the upper shaft 2 is spherical.
[0020]
FIG. 3 shows still another embodiment of the flange coupling according to the present invention. This embodiment differs from the above embodiments in that the pressure receiving surface 7b of the spacer plug 6 held by the second coupling member, which supports the upper shaft 2, is formed as an annular projection. According to this embodiment, sagging and misalignment can be prevented.
[0021]
FIG. 4 shows still another embodiment of the present invention. A collar 11 is attached near the end of the upper shaft 2. The collar 11 is fitted in a groove 2c formed in the upper shaft 2. The inner diameter of the coupling member 1c into which the upper shaft 2 is fitted is such that a portion 24 corresponding to the collar 11 has a larger diameter than other portions. On the other hand, a recess 23 is formed in the spacer plug 6c held by the coupling member 1b so that the shaft end of the upper shaft 2 can be accommodated. When the flange 11 comes into contact with the edge 7c of the recess 23 of the spacer plug 6, the axial load is supported.
[0022]
In the structure of the embodiment shown in FIGS. 3 and 4, the acting radius of the axial load on the pressure receiving surfaces 7b and 7c is large. Therefore, the moment for suppressing the angular displacement on the pressure receiving surfaces 7b and 7c also increases, and the angular displacement of the upper shaft 2 with respect to the coupling member 1a can be suppressed. In the embodiment of FIG. 3, an annular projection may be provided on the upper shaft 2, and the contact surface of the annular projection may be spherical or tapered.
[0023]
FIG. 5 shows still another embodiment of the present invention. In this embodiment, the thickness of the spacer plug 6 is smaller than that of the above embodiment. The spacer plug 6 is a stepped disk, and the inner side of the second coupling member 1d is connected to the first coupling member 1a on the other side to hold the large diameter portion of the spacer plug 6. It is larger in diameter than the part. The radius of contact between the spacer plug 6 and the coupling member 1b is larger than the radius of contact between the spacer plug 6 and the upper shaft 2.
[0024]
Therefore, when an axial load is applied, the spacer plug 6 is elastically deformed as shown in an exaggerated manner in FIG. 5, and only the outer peripheral side of the pressure receiving surface 7d of the upper shaft 2 contacts. Thereby, the angular displacement of the upper shaft 2 with respect to the coupling member 1a can be suppressed for the same reason as shown in the embodiment of FIGS. In addition, since the spacer plug 6 is elastically deformed, an excessive surface pressure is prevented from being generated on the pressure receiving surface 7, and the upper shaft 2 is prevented from being angularly displaced with respect to the coupling member 1 a due to the pressure receiving surface 7. it can.
[0025]
The above embodiments can be used alone or in combination. In each of the above embodiments, the case of the vertical axis has been described as an example, but the present invention can be applied to the case of the horizontal axis.
[0026]
【The invention's effect】
According to the present invention, since the pressure receiving member housed inside the flange coupling aligns the shaft, when an axial load is generated, a force acts in a direction to match the center of the shaft with the coupling member. The misalignment of the flange with respect to the shaft can be reduced. Thereby, the reliability of the flange coupling can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of one embodiment of a coupling according to the present invention.
FIG. 2 is a longitudinal sectional view of another embodiment of the coupling according to the present invention.
FIG. 3 is a longitudinal sectional view of still another embodiment of the coupling according to the present invention.
FIG. 4 is a longitudinal sectional view of still another embodiment of the coupling according to the present invention.
FIG. 5 is a longitudinal sectional view of still another embodiment of the coupling according to the present invention.
[Explanation of symbols]
1a, 1b coupling member, 2 upper shaft, 3 radial gap, 4 sliding key, 5 key groove, 6 spacer plug (pressure receiving member), 7 pressure receiving surface, 8 local cured portion, 9 ... Locally cured portion, 10... Pressure receiving member, 11. Rim, 12... Radial gap, 13.

Claims (8)

A flange coupling having a first coupling member coupled to a first shaft and a second coupling member coupled to a second shaft, wherein the first coupling member is held by the second coupling member. 3. A flange coupling, comprising: a pressure receiving member having a surface in contact with an end of the shaft, which is one of a tapered surface, a spherical surface, and a ring-shaped projection. A flange coupling having a first coupling member coupled to a first shaft and a second coupling member coupled to a second shaft, wherein the first coupling is held on the first shaft. A flange having an outer diameter larger than the outer diameter of the mounting portion, and a pressure receiving member held by the second coupling member and in contact with the ring. In a flange coupling having a first coupling member coupled to a first shaft and a second coupling member coupled to a second shaft, the flange coupling includes a first coupling member and a second coupling member. A pressure receiving member that can be brought into contact with both of them, wherein the acting radius of the load from the first shaft to the pressure receiving member and the load radius from the second coupling member are made different from each other; . The flange according to any one of claims 1 to 3, wherein the first flange member and the first shaft are relatively movable in an axial direction using a first sliding key. Coupling. A key groove in which the first slide key fits is formed in the first flange member, and a gap between the key and the key groove in the first slide key portion is defined by an inner diameter of the first flange member and a first groove. The flange coupling according to claim 4, wherein the clearance is smaller than a gap between the shaft and the outer diameter of the shaft. 4. The device according to claim 1, wherein at least one of a surface of the pressure receiving member contacting the first shaft and a surface of the first shaft contacting the pressure receiving member is locally cured. 5. Flange coupling according to item. 4. The pressure receiving member according to claim 1, wherein the pressure receiving member is fixed to a first shaft, and a hardness of a surface of the pressure receiving member on a side opposite to a fixed side is higher than other portions. Flange coupling according to item. The flange coupling according to any one of claims 1 to 3, wherein the pressure receiving member is movable in an axial direction.

Images