DE1963928A1 - Storage of rotor blades for rotary wing aircraft - Google Patents

Description

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I. es G ex'schmi tt-Bölkow-Blohm
society with
limited liability
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Gttobrunn, December 16, 1969 2VP2 Hb / räu Bp 866

; the rotor blades of rotary wing aircraft.

A fundamental distinction is made between rotors of rotary wing aircraft three types of blade connections: the rigid, the semi-rigid and the articulated blade connection. With the rigid blade connection the rotor blades are firmly connected to the rotor head. For reasons of control and strength, however, it is expedient to connect the rotor head to the rotor shaft in an articulated manner. However, rotor blades can also be provided which absorb impact and pivoting moments through elastic deformability.

With the articulated blade connection, the rotor blades are connected to the rotor head via flapping and swivel joints; a so-called cardanic blade suspension is provided for the semi-rigid blade connection. There are already rotors known, in which diametrically opposed rotor blades without flapping and swivel joints by packet-like combined, torsionally elastic tension lamellas are blind with each other ν.

About a rotary movement of the rotor blades around their longitudinal axes to enable, i.e. to adjust the blade angle, additional blade connections are required for all of the aforementioned blade connections.

70002

From the German Patent Office

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storage required. For example, from US Pat. No. 3,193,019, a blade connector is known in which the individual rotor blades are rotatably mounted around their longitudinal axes by two spherical bearings. Such a leaf storage has the disadvantage that the leaf flies are not unambiguous can be accommodated by one of the two Shäric camps, so that both bearings and their fastening elements are each used solely to absorb the centrifugal forces and moments of the blade must be designed. The arrangement of the bearings is therefore statically indeterminate. In addition, there is a length compensation when stretching or heat not possible.

The object on which the present invention is based is to provide a mounting for eotor blades of rotary wing aircraft to create in rotor arms arranged on the rotor head, in which the rotor blades are rotatable about their longitudinal axes and the blade centrifugal forces are clearly absorbed by only one of the bearings assigned to each rotor blade.

This is achieved according to the invention in that the individual Rotor blades via a spherical bearing connection and by means of a coaxial to the axis of rotation of the blade angle adjustment bearing journals rigidly connected to the blade spar are mounted on the respective rotor arm in a wired manner.

According to the German Offenlegungsschrift 1 431 171 is a rotor blade connection is known in which the rotor blades are supported by spherical bearings with a spherical joint surface on the rotor head are attached. With this articulated blade connection, however, both flapping and pivoting movements of the rotor blades should be as well as a rotational movement of the same about their longitudinal axes essentially through closed ones in the main force direction Joint bearing surfaces are made possible.

With such an articulated blade connection, even with a relatively high surface pressure on the sliding surfaces the spherical bearings, especially under the effect of the centrifugal forces of the blades, Blade movements possible} However, the spherical plain bearings are subject to heavy wear and must therefore

209835/0002
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According to the present invention, a bearing arrangement for rotor blades is proposed in which the individual rotor blades are rotatably supported by a spherical bearing connection and by a further bearing in the manner of a radial bearing. The bearings are jointly absorbed and the effective surface pressures on the sliding surfaces of the joint bearing connection are reduced.

Ur. a 31attwin ": elverstellung to ensure even at high Flächenpresrungen to the sliding surfaces of the pivot bearing connection, this can then such ^r; be estaltet that the rotor blade is löigelstück movable about one, which is rigidly connected by an axially parallel to the rotor axis of rotation bolt with the rotor arm. In this way, joint bearing surfaces that are closed in the direction of the centrifugal forces and at the same time a bearing axis running transversely to the direction of main stress are achieved.

The invention is explained in more detail below using an example as shown in the drawing, namely shows

1 shows a longitudinal section extending in a vertical plane by a rotor arm in the area of the blade bearing and

FIG. 2 shows a section according to FIG. 1, but in a horizontal direction Level.

The spar end 1 of a rotor blade, not shown, is designed in the, if necessary, as an angular bearing sleeve.

209835/0002

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formed Eotorarm 2 rotatably mounted. It is also available with an in the plane of the sheet arranged ring 3 with a hollow spherical shape Slideway and one coaxial to the axis of rotation 4 of the blade angle adjustment running journal 5 is provided. The axis of rotation 4 of the blade angle adjustment, which is advantageous with the center of gravity of the rotor blade can coincide, runs through the center of the ring 3 · The ring 3 is around a Movable ball piece 6, which is rigidly connected to the rotor arm 2 by a bolt 7 arranged axially parallel to the rotor axis of rotation is. For this purpose, in the example, a bolt shank guided through bores in the rotor arm 2 is provided with a fixed one Head and a threaded part for a nut 8 are provided. The ball piece 6 can by a known frictional connection be attached to the bolt shank. Everything together forms the pivot bearing connection 11.

The bearing journal 5 is in a bearing bush 9 cLes rotor arm 2 rotatably mounted. Instead of such an undivided radial plain bearing with a bearing bush, however, a bearing with split bearing shell be provided if this is necessary for assembly reasons. A use of a radial roller bearing is also possible. A lever 10 firmly connected to the spar end 1 is used to adjust the blade angle.

To reduce the sliding friction, all bearing surfaces of the blade bearing can be coated with lubricants known per se, e.g. a Teflon-metal mixture, molybdenum disulfide or the like. Be coated.

According to the present invention, a structurally simple mounting for rotor blades is therefore proposed. It is it is immaterial whether a rigid, semi-rigid or articulated blade connection is provided.

Patent claims:

209835/0002

Claims (1)

Claims Bearing for rotor blades of rotary wing aircraft in rotor arms arranged on the rotor head, characterized by that the individual rotor blades via a spherical bearing connection (11) and mediating a bearing pin rigidly connected to the blade spar coaxially to the axis of rotation (4) of the blade angle adjustment (5) are rotatably mounted on the respective rotor arm (2). Bearing according to claim 1, characterized in that the rotor blade in the joint bearing connection (11) is movable around a ball piece (6), which is supported by a bolt (7) running axially parallel to the rotor axis is rigidly connected to the rotor arm (2). 3. Storage according to claim 1, characterized in that it is marked net that the bearing pin (5) in the rotor arm (2) in a Bearing bush (9) is rotatably mounted. 20983S / 0002 Blank page