JPS63228936A - Bind ring - Google Patents

Abstract

PURPOSE:To obtain a lightweight, high-strength insulating bind ring arousing no question in its insulation by surrounding the whole surface of carbon fiber reinforced plastic with thin insulating fiber reinforced plastics. CONSTITUTION:After a yarn composed of epoxy resin has been wound under tension round a dividable metal mold 16, the whole body of a product thus obtained is cured by heating to manufacture a glass fiber reinforced plastic (GFRP) ring 11. Then, said GFRP ring 11 is subjected to a cutting work to form a thin ring with a groove-shaped section. Thereafter, a unidirectional carbon fiber impregnated with the same epoxy resin as that impregnated in said glass fiber is wound under tension round said part subjected to the cutting work. Then, a unidirectional glass fiber impregnated with the same epoxy resin as that used in the GFRP ring 11 is wound under tension from above said carbon fiber to form a GFRP cover 11b of which the whole body is cured by heating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an insulating binding ring for supporting a coil or a commutator of an electric machine, such as a rotating electric machine.

(Prior Art) Centrifugal force is applied to the coil end of a cylindrical rotor during rotation, causing the coil to deform. When rotating at high speed with a large diameter, this centrifugal force becomes strong and the coil deforms significantly, causing damage to the coil insulation or the possibility that the rotor may come into contact with the stator, leading to an accident.

Therefore, for a rotor with such a large centrifugal force,
Conventionally, as shown in Fig. 7, for example, an end ring (3) made of non-magnetic steel was attached to a support (2) fixed to the iron core (2) so as to press down the coil 0 outside the iron core through an insulator (1). The coil ends were supported by fitting together. still,
The dashed line ■ indicates the axial center line of the rotor, and the arrow (8) indicates the rotation direction of the rotor, that is, bidirectional rotation.

Additionally, glass fiber reinforced plastics (hereinafter referred to as GFRP) are used in small and medium-sized rotors instead of the end ring■, but this has a lower elastic modulus than an iron core, so a large centrifugal force is applied to it. If this happens, the coil will be deformed excessively in the radial direction and the coil insulation will be damaged.

Another example of the use of GFRP is to form a groove (1 (1)) on the surface of the copper band 0 of the commutator of a DC machine, as shown in Figure 8, and to fill this groove (1 (1) with thermosetting material such as epoxy) There is an example in which a bind ring of G F RP (11) is formed by winding a glass thread impregnated with a synthetic resin in multiple turns and heat-curing it to bind a commutator.

In this case as well, as centrifugal force and thermomechanical stress increase, G
Since the elastic modulus of F RP (11,) is lower than that of metal,
Each copper strip that forms the commutator becomes loose, causing problems such as abnormal brush wear, poor insulation, and unbalanced rotation.

(Problem to be Solved by the Invention) If the coil end is supported by an end ring as in the past, the end ring will become thicker in a rotor with large centrifugal force, and the weight will become too heavy, making it difficult to transport in some cases. Occasionally, this may cause problems.

In the rotor shown in FIG. 7, the coil ends are poorly cooled and the temperature rises rapidly. Furthermore, since both size and weight increase, there is a problem that, for example, a brushless exciter of a turbine generator cannot be overhanged onto the main body shaft, making it impossible to make it inexpensive and compact.

Therefore, carbon fiber reinforced plastic (hereinafter referred to as C
It is conceivable to use a ring made of FRP.

However, carbon fiber is electrically conductive, and if it becomes pulverized by vibration or friction, and if it adheres to an insulating surface, the surface insulation resistance decreases, causing a grounding accident, or electrical bridging occurs between coils or conductors, causing the operation of rotating electric machines. It starts to cause problems.

On the other hand, CFRP has a breaking elongation of about 0.6 to 0.9%, and
It is much smaller than the 2.5 to 3.0 of FRP. If the elongation at break is small, when a defect occurs, stress concentration at the defective part becomes large, making it easier to break.

An object of the present invention is to provide an insulating binding ring for support and binding that uses CFRP, which is lightweight and has high elastic modulus and strength, is not harmful in terms of insulation, and is less likely to cause defects in CFRP.

[Structure of the invention]

(Means for solving the problem) In order to prevent the generation of conductive powder that is harmful to insulation due to friction of CFRP, conductive CFRP is used between coils and conductors.
In order to prevent electrical bridging caused by defects and at the same time protect CFRP, which is prone to stress concentration due to defects, the entire surface of CFRP (1, 3) is covered with a thin insulating film, as shown in the cross-sectional view in Figure 1. Surround with fiber reinforced plastics (14) (hereinafter referred to as insulating FRP).

(Function) CFRr' is glass fiber reinforced plastics (hereinafter GF
RP) and other fiber-reinforced plastics (hereinafter referred to as F
RP) and specific strength (strength per weight) compared to metals.
, high specific modulus (modulus of elasticity per weight). Therefore, coils and conductors can be effectively supported and bound without making the rotating electric machine heavier than other materials. For example, as shown in Figure 7, a high-strength, high-modulus F is used at the coil end of the rotor.
If a bind ring is formed using RP, it can be made lighter than a metal one with the same strength.

By the way, when a FRP II binding ring is used at the coil end, elastic deformation occurs due to centrifugal force.

The maximum elongation difference Δr in the radial direction between the coil and the iron core when subjected to centrifugal force is expressed by the following equation (101), where ΔRo is the elongation in the radial direction of the iron core, and ΔRB is the elongation of the binding ring.

Δr=ΔRB−ΔRo−(101) However, it is assumed that Δr=ΔRB−ΔRo−(101). Here, the subscript B is the binding ring. represents an iron core. σ is the usable stress (elastic limit stress/safety factor)
, E represents the elastic modulus, and R represents the radius.

From equations (102) and (103), in order to make the elongation of the iron core equal to the elongation of the binding ring so that the coil does not deform when centrifugal force is applied, B EB = σB × - (104 ) It is sufficient to use a binding ring with an elastic modulus that is ΔRC. It can be seen from equation (104) that if a bind ring with a high elastic modulus is used, the radius can be increased, the usable stress can be increased, and the bind ring can be made thinner.

For example, when the usable stress is 60 kg/m2, if we use CFRP with an elastic modulus of 35,000 kg/ma, it is much higher than the elastic modulus of the iron core (approximately 21,000 kg/nu2), so the rotor of a variable speed synchronous water turbine generator motor with a diameter of 5 m is used. can be supported without deforming the coil.

Therefore, if the coil end is held and supported by an insulating FRP bind ring with a high elastic modulus that makes the radial extension of the core caused by centrifugal force almost equal to the radial extension of the coil end, the coil end can be held down and supported. No deformation,
It does not cause damage to the insulation at the coil ends.

Additionally, since it can be installed on-site, there is no problem with transportation.

In addition, by using insulating FRP with high elastic modulus,
Since the usable stress can be increased, the binding ring can be made thinner and its weight can be reduced, and high-speed rotation is also possible. Alternatively, it is possible to increase the diameter of the rotor.

Using CFRP rings in this way makes it possible to support and bind lightweight, high-strength coils and conductors, but CFRP is electrically conductive and tends to cause stress concentration due to the insulation problems and defects mentioned above. There is a problem that it becomes easy to destroy. Therefore, by surrounding the entire surface of CFRP with a thin insulating FRP that does not impair the original strength and modulus of CFRP, such as GFRP, KFRP (Kevlar fiber reinforced plastics), ALFRP (alumina fiber reinforced plastics), etc. , lightweight, high strength and no insulation problems, C
A ring that is less likely to cause defects in FRP can be provided.

Note that the insulating FRP mentioned here is CFRP.

Including GFRP, KFRP, ALFRP, etc., unidirectional fiber reinforcement is the best method to form a ring with high strength and high modulus.

(Examples) Example 1 A first example of the present invention will be described below with reference to FIGS. 1 to 3. Figure 1 is a cross-sectional view of the bind ring.The manufacturing method is as shown in Figure 2, which is a cross-sectional view of the binding ring. A thread made of unidirectional glass fiber (for example, T glass fiber manufactured by Nitto Keisha) impregnated with an epoxy resin (for example, XR521 (1) manufactured by Sumitomo 3M Co., Ltd.) is wound under a tension of approximately 35 kg/mm. After that, the whole is heated and hardened to produce a GFRP ring (11).

Next, this GFRP ring (11) is cut into a thin ring with a groove-shaped cross section as shown in FIG.

Next, unidirectional carbon fibers impregnated with the same epoxy resin as the glass fibers (for example, HM40A manufactured by Toho Rayon Co., Ltd.) are applied to the cut portion under a tension of 1.2 kg per 6,000 7-tone glass fibers. Roll it up. Next, unidirectional glass fibers impregnated with the same epoxy resin as used for the GFRP ring (11) described above were similarly wrapped around this under a tension of 7 kg per 6000 glass fibers, and the GFRP cover ( llb) is formed and the whole is heated and cured. Thereafter, the mold was removed to obtain a CFRP bind ring whose entire surface was surrounded by thin insulating FRP.

Here, if the matrices of CFRP and GFRP are the same, and their properties are different, stress such as thermal stress due to the difference in thermal expansion will occur at the interface between CFRP and GFRP, resulting in peeling. This is to prevent such problems from occurring.

In this way, CFR is lightweight and has high elastic modulus and strength.
Although P is used, an insulating binding ring that is not harmful to insulation and does not easily cause defects in CFRP can be made.

Example 2 As shown in the cross-sectional view in Fig. 4, a groove (1 (
1) Form. In this groove, a bind ring of CFRP (13) surrounded by a thin insulating FRP groove ring (4) and a cover (14a) is formed in the same manner as described in Example 1, and a commutator The copper belt (9) was tied down and supported.

In this way, because of its high strength, a small amount of insulating F
Since it is made of RP and has high elasticity, it can be tightened to prevent the commutator's copper band from loosening during rotation.

Example 3 As shown in the cross-sectional view in Fig. 5, a plurality of grooves (1 (1)) are provided on the outer surface of the rotor core (1). Similarly, a CFRP binding ring surrounded by thin insulating FRP was formed to bind and support coil 0.

By doing so, the coil 0 can be tightly bound, and since the number of air passages is increased compared to the conventional wedge-supported method, cooling is significantly improved.

Example 4 As shown in the cross-sectional view in Fig. 6, a lower coil (5A
) and temporarily fixed with a wedge, the end of the coil was wound with a thread made of high-strength glass fiber impregnated with epoxy resin (trade name: T-Glass manufactured by Nitto Keisha) under a tension of 35kg10n2, and then heated and cured. to form the lower GFRP ring (llb).

Next, after inserting the upper coil (5B), the L coil (5B)
Similarly, a thread made of unidirectional glass fiber impregnated with epoxy resin is wound under tension so as to hold it down, and then heated and cured to form the upper GFRP ring (11,c). Next, the outer peripheral surface of the upper ring (llc) of the GFRP holding the upper coil (5B) is cut into a true cylindrical shape. On the other hand, from the outer diameter of this cylinder, 0.1~
A CFRP ring (13) is produced by winding a unidirectional carbon fiber impregnated with an epoxy resin having an inner diameter as small as 0.5 mm around a winding frame (not shown) under tension and hardening it by heating. Then, the entire coil end portion is cooled with dry ice, and the CFRP ring (13) is fitted into the upper GFRP ring (llc) and cooled down. In this way, the CFRP ring (13) is replaced with the GFRP ring (l).
ie), then attach (not shown) to the surface of the upper GFRP ring (llc), divide it in half so that it can be removed, and place the metal ring, whose surface has been mold-released, one by one onto the CFRP ring (llc). Attach it slightly away from both sides of the ring (13). Next is the CFRP ring (13)
and the gap between the metal ring and the CFRP ring (13
) is wound with unidirectional glass fiber impregnated with oxy resin under tension in the same manner as described above, and then heated and cured to form a GFRP cover (lid). After that,
By removing the metal ring split in half,
A CFRP ring was obtained whose entire surface was surrounded by GFRP, which was a thin insulating FRP.

By doing this, we were able to manufacture a compact exciter that is lightweight, has good cooling performance, and can be overhanged onto the shaft of the turbine generator main body.

〔Effect of the invention〕

As explained below, the CFRP binding ring according to the present invention, which is entirely surrounded by thin insulating FRP, is lightweight, has high strength, and has little deformation under load.

Furthermore, it has the advantage of not having problems with insulation and being less susceptible to stress concentration due to defects.

By using this ring to support and bind the coils and conductors of electric machines, electric machines can be made smaller, lighter, and more compact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the bind ring of the present invention, FIGS. 2 and 3 are sectional views of an apparatus for explaining a method of manufacturing a CFRP ring, and FIGS. Figure, 6th
The figures are sectional views showing the main parts of the second, third and fourth embodiments of the present invention, and FIGS. 7 and 8 are sectional views showing the main parts of the conventional example. 13...CFRP ring, 14...Insulating FRP groove ring. 14a...Insulating FRP cover.

Claims (5)

[Claims] (1) A bind ring of carbon fiber reinforced plastics (hereinafter referred to as CFRP) whose entire surface is surrounded by insulating fiber reinforced plastics (hereinafter referred to as insulating FRP). (2) The bind ring according to claim 1, characterized in that unidirectional fibers are used as reinforcing fibers of CFRP and insulating FRP. (3) Claim 1 or 2, characterized in that glass fiber is used as reinforcing fiber of insulating FRP.
Binding ring as described in section. (4) The bind ring according to claim 3, characterized in that high-strength glass fiber is used as the glass fiber. (5) CFRP and insulating FRP matrix (
Claim 1 characterized in that the resins) are the same.
The binding ring according to any one of Items 1 to 4.