Windmill

Abstract

A windmill, characterized by connecting blade root parts to a hub in the radial direction of a windmill shaft by an undercut fitting structure which is suitable particularly for a small-sized windmill having FRP blades. By this structure, the blades can be connected to the hub at the blade root parts without basically requiring a bolt fastening structure, a reduction in the weight of the blades can be achieved, and the strength, rigidity and installation accuracy of connection parts between the blades and the hub can be satisfactorily maintained.

Description

technical field [0001] The invention relates to a windmill, in particular to a connection structure between a hub of a windmill shaft and a wing root. Background technique [0002] The wings of the windmill are usually arranged in three or so pieces, the roots of which are fixedly connected to the hub of the windmill shaft and rotate with the rotation of the windmill shaft. In particular, in a small windmill, the method of fixing the root of the wing to the hub with a through-bolt connection is the simplest and is often used. In recent years, in order to reduce the weight of high-strength and high-rigidity wings, fiber-reinforced plastics (hereinafter abbreviated as FRP) are used to form the main body of the wing. Among them, carbon fiber-reinforced plastics (hereinafter abbreviated as CFRP) are increasingly used to form the main body of the wing. section (for example, Patent Document 1). For such an FRP wing, a wing fixing method in which the above-mentioned through-bolts...

AI Technical Summary

Problems solved by technology

[0003] However, in the fixing method that has bolt holes in the wing main body and directly connects the wing main body with bolts, the bolt holes where stress concentration occurs will be the center of the bolt holes due to the vibration and centrifugal force generated by the rotation of the windmill, regardless of the magnitude of the bolt connection force. The starting point creates chaps on the wing and degrades the internals due to water intrusion into the interior of the wing

[0004] In addition, in the case where the wing body has bolt holes, in order to maintain the shape and strength of the bolt holes, it is necessary to insert a solid member inside the connecting portion, which inevitably increases the weight of the wing and damages the light weight mentioned above. The case for quantifying effects

In addition, the increase in the weight of the wing is related to the increase in the moment of inertia of the wing and the increase in the kinetic energy of the wing itself. As a result, the performance of the brake needs to be enhanced, and the cost of other parts such as the capacity of the motor, the increase in weight, and the reinforcement of the support arm are required. improve

In addition, the increase in the kinetic energy of the wing may lead to an increase in the damage to the surrounding environment once the wing is damaged and scattered

[0005] In addition, for example, in the case of small windmills that are often installed by individuals at high places in their homes or in mountain huts, the connection with bolts is likely to cause vibrations due to the need for construction accuracy.

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