Diaphragm coupling

Abstract

To provide a light-weight diaphragm coupling.SOLUTION: A diaphragm coupling 1 comprises a diaphragm 4 fixed to a drive shaft 2, a diaphragm 5 fixed to a driven shaft 3, and a cylindrical member 6 connecting the pair of diaphragms 4, 5, where the cylindrical member 6 has a large diameter part 6A and small diameter parts 6B, 6C, and one of the large diameter part 6A and the small diameter parts 6B, 6C is formed thinner than the other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a diaphragm coupling, for example, a diaphragm coupling that transmits a rotational force of a rotating shaft to a driven shaft. [Background technology]

[0002] 2. Description of the Related Art In rotary machines such as gas turbines and steam turbines, a coupling is disposed between the rotating shaft and a driven shaft of an auxiliary machine, and the rotational force of the rotating shaft is transmitted to the driven shaft via the coupling to drive the auxiliary machine.

[0003] For example, the coupling shown in Patent Document 1 transmits power from a power transmission mechanism to a gear box, and includes one diaphragm unit attached to the output shaft of the power transmission mechanism, the other diaphragm unit attached to the input shaft of the gear box, and a center tube disposed between the side tubes of both diaphragm units. In this way, the use of diaphragms makes it possible to absorb misalignment between the output shaft and the input shaft.

[0004] The side tube has a small diameter portion and a large diameter portion, the small diameter portion being fixed to the diaphragm, and the large diameter portion being fixed to the center tube. The center tube is connected to the large diameter portion of the side tube, so that the center tube can be configured to have a large diameter, and the natural frequency of the center tube is increased. This allows the critical speed during rotation of the coupling to be set outside the range of the steady operating speed of the output shaft of the power transmission mechanism. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-337394 A (page 2, figure 3) Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the coupling of Patent Document 1, although the critical speed of the coupling can be controlled, the center tube has a large diameter, which may increase the weight.

[0007] The present invention has been made in consideration of these problems, and has an object to provide a lightweight diaphragm coupling. [Means for solving the problem]

[0008] In order to solve the above problems, the diaphragm coupling of the present invention comprises: A diaphragm coupling including a diaphragm fixed to a drive shaft, a diaphragm fixed to a driven shaft, and a cylindrical member connecting the pair of diaphragms, The cylindrical member has a large diameter portion and a small diameter portion, One of the large diameter portion and the small diameter portion is formed thinner than the other. According to this, one of the large diameter portion and the small diameter portion can be formed thin, so that the diaphragm coupling can be made lightweight.

[0009] the cylindrical member has one fixed portion fixed to the diaphragm on the rotating shaft side, another fixed portion fixed to the diaphragm on the driven shaft side, and a base portion having a larger diameter than at least the other fixed portion, A thick portion that is thicker than the base portion may be provided on the other fixed portion side. This allows the thick-walled portion to withstand the torsional stress that occurs when the rotation speed of the rotating shaft changes, suppressing deformation of the connection portion between the base portion and the other fixed portion and improving durability. In addition, since the thick-walled portion is formed locally, the weight can be reduced compared to when the overall thickness is increased.

[0010] The thick portion may be welded to the diaphragm on the driven shaft side. According to this, since the thick portion has a large area, it is easy to weld the thick portion to the diaphragm on the driven shaft side.

[0011] The cylindrical member may be formed by pressing. According to this, since the cylindrical member is constructed as a single piece by press working, the strength of the connection portion between the other fixing portion and the base portion can be increased.

[0012] The connecting portion between the another fixing portion and the base portion may be tapered. According to this, the corners between the other fixing portion and the connecting portion and the corners between the base portion and the connecting portion are formed gently, so that the stress acting on these corners can be dispersed in the axial direction.

[0013] The thickness of the thick portion may be 1.5 to 5 times the thickness of the base portion. According to this, the thick portion has a sufficient thickness, and therefore has high strength against stress.

[0014] The base portion may be axially longer than the other fixed portion. This allows the thickness of the base portion, which is long in the axial direction, to be thin, thereby making it possible to reduce the weight. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing a diaphragm coupling according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a partially enlarged cross-sectional view showing the periphery of the diaphragm on the rotating shaft side. [Diagram 3] FIG. 4 is a partially enlarged cross-sectional view showing the periphery of a diaphragm on a driven shaft side. [Figure 4] FIG. 5 is a cross-sectional view showing a diaphragm coupling according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a diaphragm coupling according to the present invention will be described below with reference to the accompanying drawings. EXAMPLES

[0017] A diaphragm coupling according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In the following description, the left and right sides of the paper in Fig. 1 correspond to the left and right directions of the diaphragm coupling.

[0018] As shown in FIG. 1, the diaphragm coupling 1 of this embodiment is a shaft coupling that is disposed between a rotating shaft 2 serving as a drive shaft of a rotating machine and a driven shaft 3 of an auxiliary machine, and absorbs misalignment between the rotating shaft 2 and the driven shaft 3 to transmit the rotational force of the rotating shaft 2 to the driven shaft 3.

[0019] The rotating shaft 2 and the driven shaft 3 are metal members having a hollow structure.

[0020] The diaphragm coupling 1 is mainly composed of a first diaphragm 4, a second diaphragm 5, and a cylindrical member 6. Incidentally, for example, a cooling fluid can be passed through the rotating shaft 2, the driven shaft 3, and the cylindrical member 6 to cool a motor and a turbine (not shown).

[0021] 1 and 2, the first diaphragm 4 is an annular metal plate having an opening 4a in the center. An inner diameter portion 41 around the opening 4a is formed to be thicker than other portions on the outer diameter side. A right end portion 6D serving as one fixing portion of the cylindrical member 6 is fixed to the inner diameter portion 41 by welding in the axial direction.

[0022] The first diaphragm 4 is disposed on the left side of the flange 2a of the rotating shaft 2, and an annular guard 7 is disposed on the left side of the first diaphragm 4. The first diaphragm 4 and the guard 7 are fixed to the flange 2a of the rotating shaft 2 with bolts and nuts.

[0023] The guard 7 has a larger diameter than the portion of the cylindrical member 6 at the attachment position. When the first diaphragm 4 is excessively bent, the guard 7 causes a convex rib portion 613 of the cylindrical member 6, which will be described later, to come into contact with its inner peripheral surface 7a, thereby functioning to prevent the first diaphragm 4 from being excessively deformed.

[0024] 1 and 3, the second diaphragm 5 has substantially the same structure as the first diaphragm 4. A left end portion 6E of the cylindrical member 6, which serves as another fixed portion, is fixed in the axial direction to an inner diameter portion 51 of the second diaphragm 5 by welding.

[0025] This second diaphragm 5 is disposed to the right of a third diaphragm 8 fixed to the end of the driven shaft 3, and a guard 7' is disposed to the right of the second diaphragm 5. The third diaphragm 8 constitutes a part of the driven shaft 3. Furthermore, a guard 7'' is disposed to the left of the third diaphragm 8. The third diaphragm 8 has a structure obtained by inverting the second diaphragm 5 in the axial direction. Furthermore, the guard 7' has a structure obtained by inverting the guard 7 in the axial direction. Furthermore, the guard 7'' has approximately the same structure as the guard 7.

[0026] The second diaphragm 5 and the guards 7', 7'' are fixed to the third diaphragm 8 by bolts and nuts.

[0027] 1 to 3, the cylindrical member 6 has a large diameter portion 6A constituting a base portion, and small diameter portions 6B and 6C. The small diameter portion 6B is provided on the right side of the large diameter portion 6A, and the small diameter portion 6C is provided on the left side of the large diameter portion 6A. The large diameter portion 6A is longer in the axial direction than the small diameter portions 6B and 6C.

[0028] In this manner, since the cylindrical member 6 has the large diameter portion 6A having a larger diameter than the small diameter portions 6B, 6C, the natural frequency of the cylindrical member 6 is increased, and as a result, the critical speed during rotation of the diaphragm coupling 1 is set to be outside the range of the steady operating speed of the rotating shaft 2.

[0029] Specifically, the cylindrical member 6 has a divided structure including a first member 61, a second member 62, and a third member 63. Although the present embodiment illustrates an embodiment in which the cylindrical member 6 is composed of three members, the members constituting the cylindrical member can be freely changed. Also, the cylindrical member does not have to have a divided structure, and may be composed of a single member.

[0030] Referring particularly to Figure 2, the first member 61 on the right side includes a tubular portion 611 constituting the small diameter portion 6B, a right end portion 6D of the tubular portion 611, i.e., the right end portion 6D of the tubular member 6, and a flange portion 612 at the left end of the tubular portion 611.

[0031] The thickness L1 of the right end portion 6D is greater than the thickness L2 of the cylindrical portion 611 (L1>L2).

[0032] The right end 6D is provided with a protruding ridge 613 that protrudes radially outward. The protruding ridge 613 is disposed on the inside of the inner circumferential surface 7a of the guard 7.

[0033] The flange portion 612 is formed so as to protrude radially outward from the left end portion of the cylindrical portion 611. The flange portion 612 is fixed to a flange portion 622 of the second member 62, which will be described later, with bolts and nuts.

[0034] Further, an annular protrusion 614 having a smaller diameter than the second member 62 is provided on the left surface of the flange portion 612 so as to protrude to the left. By inserting this annular protrusion 614 into the inside of the second member 62, the relative inclination between the first member 61 and the second member 62 is regulated.

[0035] Referring particularly to FIG. 2, the second central member 62 includes a cylindrical portion 621 that constitutes the large diameter portion 6A, a flange portion 622 on the right end, and a flange 623 on the left end (see FIG. 1).

[0036] The cylindrical portion 621 has a larger diameter than the cylindrical portion 611 of the first member 61 .

[0037] Still, the cylindrical portion 621 includes a plurality of portions 621a having a plate thickness L10 and a plurality of portions 621b having a plate thickness L10' (L10 < L10'). The portion 621a is a portion machined by a lathe or the like for adjusting the rotational balance, for example, and the portion 621b is an un-machined portion.

[0038] As described above, the flange portion 622 is fixed to the flange portion 612 of the first member 61 with bolts and nuts. Further, the flange 623 is fixed to the flange portion 632 of the third member 63, which will be described later, with bolts and nuts (see FIG. 1).

[0039] Particularly referring to FIG. 3, the left third member 63 includes a cylindrical portion 631A that forms the large-diameter portion 6A, a cylindrical portion 631B that forms the small-diameter portion 6C, a connecting cylindrical portion 631C as a connecting portion, the left end portion of the cylindrical portion 631B, that is, the left end portion 6E of the cylindrical member 6, and a flange portion 632 (see FIG. 1).

[0040] The cylindrical portion 631A has substantially the same diameter as the cylindrical portion 621 of the second member 62.

[0041] The cylindrical portion 631A is disposed on the right side of the connecting cylindrical portion 631C, and the cylindrical portion 631B is disposed on the left side of the connecting cylindrical portion 631C. Still, the cylindrical portion 631A includes a portion 631a and a portion 631b formed by turning. The portion 631a has a plate thickness L11, and the portion 631b has a plate thickness L11' (L11 < L11').

[0042] The connecting cylindrical portion 631C has a tapered shape that tapers toward the left. Specifically, the cylindrical portion 631A, the cylindrical portion 631B, and the connecting cylindrical portion 631C are formed by pressing a single metal cylindrical material.

[0043] The thickness L3 of the cylindrical portion 631B is thicker than the thicknesses L11, L11' of the cylindrical portion 631A (L3>L11, L11'). Specifically, in this embodiment, the thickness L3 of the cylindrical portion 631B is about three times the thicknesses L11, L11' of the cylindrical portion 631A. That is, the cylindrical portion 631B is the thick-walled portion in this embodiment.

[0044] Furthermore, the thickness L3 of tubular portion 631B may be freely changed as long as it is thicker than the thicknesses L11, L11' of tubular portion 631A, and preferably, the thickness L3 of tubular portion 631B is 1.5 to 5 times the thicknesses L11, L11' of tubular portion 631A.

[0045] Furthermore, the plate thickness L4 of the connecting tubular portion 631C is substantially the same as the plate thickness L11 of the tubular portion 631A (L4=L11).

[0046] Furthermore, the plate thicknesses L11, L11' of the cylindrical portion 631A are approximately the same as the plate thicknesses L10, L10' of the cylindrical portion 621 (L10, L10'=L11, L11').

[0047] As described above, in the cylindrical member 6 of this embodiment, the plate thickness of the large diameter portion 6A, i.e., the plate thicknesses L10, L10' of the cylindrical portion 621 and the plate thicknesses L11, L11' of the cylindrical portion 631A, is formed to be thinner than the plate thicknesses of the small diameter portions 6B, 6C, i.e., the plate thickness L2 of the cylindrical portion 611 and the plate thickness L3 of the cylindrical portion 631B, thereby making the diaphragm coupling 1 lightweight.

[0048] In addition, since the large diameter portion 6A, which is axially longer than the small diameter portions 6B, 6C, is formed thinner than the small diameter portions 6B, 6C, the weight of the diaphragm coupling 1 can be further reduced.

[0049] In the diaphragm coupling 1 of this embodiment, the critical speed of the diaphragm coupling 1 can be controlled by providing the large diameter portion 6A, which is larger than the small diameter portions 6B, 6C, in the cylindrical member 6, but the circumferential speeds of the large diameter portion 6A and the small diameter portions 6B, 6C are different when the rotating shaft 2 rotates. Therefore, for example, when the rotating shaft 2 starts, accelerates, decelerates, etc., stress acts locally on the connection portion between the large diameter portion 6A and the small diameter portions 6B, 6C, especially on the connection portion between the large diameter portion 6A and the small diameter portion 6C on the driven shaft 3 side.

[0050] In the diaphragm coupling 1 of this embodiment, the cylindrical portion 631B having the left end portion 6E on the driven shaft 3 side is a thick-walled portion that is thicker than the large diameter portion 6A. This allows the cylindrical portion 631B to bear the stress in the torsional direction that occurs when the rotation speed of the rotating shaft 2 changes, so that deformation of the connecting cylindrical portion 631C that is the connecting portion between the large diameter portion 6A and the small diameter portion 6C can be suppressed, improving durability.

[0051] Moreover, the left surface of the left end 6E of the cylindrical portion 631B is welded to the right surface of the inner diameter portion 51 of the second diaphragm 5. In this manner, the thick portion has a wide area, and the left end 6E of the cylindrical portion 631B, which is the thick portion, is welded to the second diaphragm 5, so that there is little risk of distortion or holes being formed by welding, and the welding operation is easy.

[0052] Furthermore, since the right end 6D of the cylindrical member 6 welded to the first diaphragm 4 is also a thick portion, the welding operation between the first diaphragm 4 and the right end 6D of the cylindrical member 6 can be performed easily.

[0053] Furthermore, since the third member 63 is formed by pressing a single metal tubular material, the strength of the connecting tubular portion 631C can be increased.

[0054] In addition, the connecting tubular portion 631C has a tapered shape that reduces in diameter toward the left side. With this, the corners between the connecting tubular portion 631C and the tubular portion 631A and the corners between the connecting tubular portion 631C and the tubular portion 631B are gently formed, so that the stress acting on these corners can be dispersed in the axial direction.

[0055] Furthermore, the thickness of the cylindrical portion 631B, that is, the thickness of the small diameter portion 6C is three times the thickness of the large diameter portion 6A, and since the small diameter portion 6C has a sufficient thickness, it has high strength against stress.

[0056] In this embodiment, an example is given of a form in which small diameter portions 6B, 6C are provided at both ends of the large diameter portion 6A, but as long as the other fixing portion on the driven shaft side is a small diameter portion, the other portions, i.e., the base portion and one fixing portion, may be large diameter portions. EXAMPLES

[0057] Next, a diaphragm coupling according to a second embodiment will be described with reference to Fig. 4. Note that a description of the same configuration as in the previous embodiment will be omitted.

[0058] As shown in FIG. 4, in the diaphragm coupling 100 of the second embodiment, both left and right ends of the cylindrical member 60 are large diameter portions 60B, 60C, and the central base portion of the cylindrical member 60 is a small diameter portion 60A.

[0059] The left end tubular portion 600 of the large diameter portion 60C is a thick-walled portion formed thicker than the plate thicknesses of the small diameter portion 60A and the connecting tubular portion 631C. In addition, the right end portion 601 of the large diameter portion 60B is a thick-walled portion formed thicker than other portions of the large diameter portion 60B.

[0060] Since the torsional stress that occurs when the rotational speed of the rotating shaft 2 changes can be received by the thick-walled tubular portion 600, deformation of the connecting tubular portion 602, which is the connecting portion between the tubular portion 600 and the small diameter portion 60A, can be suppressed, and durability is improved.

[0061] In this embodiment, the small diameter portion 60A, which is the base portion, is formed thinner than the large diameter portions 60B and 60C. However, the large diameter portions may be formed thinner than the small diameter portions.

[0062] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0063] For example, in the first and second embodiments, the cylindrical member is asymmetrical, but it may be symmetrical.

[0064] In addition, in the above-mentioned Examples 1 and 2, a configuration was exemplified in which the base of the tubular member was formed thinner than both ends, i.e., the one fixing portion and the other fixing portion, but the one fixing portion and the other fixing portion may also be formed thinner than the base.

[0065] In addition, in the above-mentioned Examples 1 and 2, a configuration was exemplified in which the base of the tubular member is longer in the axial direction than both ends, i.e., the one fixing portion and the other fixing portion, but the one fixing portion and the other fixing portion may also be longer in the axial direction than the base.

[0066] In addition, in the first and second embodiments, the connecting portion between the large diameter portion and the small diameter portion is formed to be thinner than the other fixing portions, but it may be formed to be thick like the other fixing portions.

[0067] In addition, in the above-mentioned Examples 1 and 2, an example was given of the tubular member being fixed to the first diaphragm 4 and the second diaphragm 5 by welding, but this is not limited to this and the tubular member may be fixed by another fixing means such as a bolt or nut.

[0068] In addition, in the first and second embodiments, the third diaphragm 8 constitutes a part of the driven shaft 3, but the configuration of the third diaphragm 8 may be omitted. In this case, for example, an annular flange may be provided on the right end portion of the driven shaft 3, and the second diaphragm 5 may be directly connected to the annular flange. [Explanation of symbols]

[0069] 1 Diaphragm Coupling 2 Rotation Axis 3 Driven axis 4 First diaphragm (diaphragm on the rotating shaft side) 5 Second diaphragm (driven shaft side diaphragm) 6 Cylindrical member 6A Large diameter part (base) 6B,6C Small diameter part 6D Right end (one fixed part) 6E Left end (other fixed part, thick part) 631C Connecting tubular part (connecting part)

Claims

1. A diaphragm coupling including a diaphragm fixed to a drive shaft, a diaphragm fixed to a driven shaft, and a cylindrical member connecting the pair of diaphragms, The cylindrical member has a large diameter portion and a small diameter portion, A diaphragm coupling, wherein one of the large diameter portion and the small diameter portion is formed thinner than the other.

2. the cylindrical member has one fixed portion fixed to the diaphragm on the rotating shaft side, another fixed portion fixed to the diaphragm on the driven shaft side, and a base portion having a larger diameter than at least the other fixed portion, 2. The diaphragm coupling according to claim 1, wherein a thick portion that is thicker than the base portion is provided on the side of the other fixed portion.

3. 3. The diaphragm coupling according to claim 2, wherein the thick portion is welded to the diaphragm on the driven shaft side.

4. 3. The diaphragm coupling according to claim 2, wherein the cylindrical member is formed by pressing.

5. 3. The diaphragm coupling according to claim 2, wherein a connecting portion between said another fixing portion and said base portion is tapered.

6. 3. The diaphragm coupling according to claim 2, wherein the thickness of the thick portion is 1.5 to 5 times the thickness of the base portion.

7. 7. A diaphragm coupling according to claim 2, wherein the base portion is axially longer than the other fixed portion.

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