GB2129554A

GB2129554A - Attitude gyro for projectile

Info

Publication number: GB2129554A
Application number: GB08111112A
Authority: GB
Inventors: Ernst Gruber
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1980-04-16
Filing date: 1981-04-09
Publication date: 1984-05-16
Also published as: FR2538540A1; GB2129554B; DE3014480C1

Abstract

An attitude stabilising gyro for a missile has a cardanic suspension for the rotor mounted in a frame in bearing assemblies, the frame being mounted in bearings for rotation about a further axis. The bearings 3, 4, 5, 6 and 8 of the rotor 1 and frames 2 and 7 being elastically mounted with a comparatively slight clearance and also having a rigid supporting bearing 21, 22 or surface 2.2, 7.3, 7.2, 10.1, with comparatively large clearances d1,7, d2,7 d7,10 therebetween. The elastical bearings being thus relieved of further load when certain predetermined acceleration values is exceeded. <IMAGE>

Description

SPECIFICATION Attitude gyro for projectile This invention relates to an acceleration resistant attitude gyro for a missile with a cardanic gyro rotor suspension system secured in bearings to a frame which is mounted in bearings for rotation about a further axis.

In gyros of this kind a comparatively small and heavy rotor is spun-up shortly before the missile is launched or during launching, this being achieved by means of gases generated by a combustible composition which act on parts of the rotor forming a turbine to set the latter in rotation to a few thousand r.p.m. in a short time. During this run-up phase the cardanic suspension of the rotor has to be locked. When the required speed is reached the suspension is then released. This release takes place when the projectile is subject to very high acceleration which in some cases may exceed 104g. The acceleration forces are transmitted to the frame and the rotor solely through the bearings, which have to be oversized in order to avoid damage but this adversely affects the sensitivity of the gyro.Despite the oversizing of the bearings the acceleration resistant properties are comparatively limited.

This invention has an object to provide an acceleration resistant gyro for a missile which remains capable of performing under high acceleration.

According to this invention there is provided an acceleration resistant gyro for a missile with a cardanic gyro rotor suspension system secured in bearings to a frame which is mounted in bearingsfor rotation about a further axis, characterized by the bearigs mounting the rotor and those mounting the frame having, at least: (a) one elastically mounted bearing and a small clearance between the parts mounted by the bearing, and (b) a rigid support bearing surface with a larger clearance between the parts mounted by the bearing whereby loading on the elastically mounted bearing is relieved at and above a predetermined acceleration force, are exceeded.

This invention is further described and explained below in more detail with reference to an embodiment shown by way of example in the accompanying drawings, wherein: Figure 1 shows a sectional view along the rotor axis through a gyro according to the invention, Figure 2 shows a section perpendicular to the axis of the gyro rotor of Figure 1.

In the attitude gyro shown in Figures 1 and 2 a rotor 1 is rotatably mounted in a first frame 2 by ball bearing assemblies 3 and 4. The frame 2 itself is further mounted in ball bearing assemblies 5 and 6 within a second frame 7 in such a way as to be rotatable about an axis 2.2 perpendicular to the gyro rotor axis 1.1. The second frame 7 is rotatably suspended in ball bearing assemblies 8 and 9 (Figure 2) in a housing 10 and provided with a transducer 11 which indicates changes in the angle between frame 7 and the housing 10.

In the frames 2 and 7 and also in the housing 10 bores 12, 13 and 14 are provided which are coaxial with one another and through which a propulsive gas is guided from a gas generator 15 and in a tangential direction to impinge onto the rotor 1, where it encounters the stepped turbine vanes 1.1 which have been formed in the surface of the rotor 1.

The gyro is built into a missile in such a way that the acceleration on launch (arrow b) acts in the direction shown along the axis 7.1 of the frame. A gyro installed in this manner is used, for example, to stabilizethe roll movement of the missile.

Where the acceleration forces act on the gyro in the direction shown the bearings 3 and 4 of the rotor and also the bearings Sand 6 of the frame 2 are embedded in rings 16,17,18 and 19, of a tough elastic material. The otherwise rigid bearings 3 to 6 may thus yield in a direction perpendiculartothe bearing axis under the effect of acceleration force.

The bearings 8 and 9 of the second frame 7 are secured in the housing 10 or on the axis of the frame in such a way as to enable axial movement to take place in a direction opposite to the acceleration force b. For this purpose the bearing 8 is elastically supported in the axial direction by a spring 20.

The high acceleration force occuring in the direction shown in launching cause the following effects: Under the influence of the mass moment of inertia the spring 20 is compressed until the surfaces 7.2.

and 10.1 of the second frame and the housing respectively and normally situated at a defined distance d7,10 apart come into contact. The surfaces 7.2. and 10.1 have a defined roughness and size and thus calculatable friction. The spring 20 and also the roughness and the distanced7,10 of the surfaces 7.2.

and 10.1 are coordinated in such a way that the frame 7 is reliably supported by the housing 10 and locked when a certain preselected acceleration value is exceeded.

Owing to inertia the elastic rings 18 and 19 will continue to deform until the surfaces 2.2. and 7.3 of the first and second frames respectively and normally situated at a defined distance d2,7 from each other are also in contact. The elastic properties of the rings 18 and 19 and also the distanced2,7 are coordinated in such a way that the bearings 5 and 6 are not subject to further load beyond a certain predetermined acceleration force, as the frame 2 is then directly supported by the frame 7 via the contact surfaces 2.2 and 7.3, the degree of roughness being here again defined.

Finally, due to the acceleration force, the toughly elastic rings 16 and 17 of the bearings 3 and 4 likewise undergo deformation until the gyro rotor axes 1.3 and 1.4 are displaced sideways to the distance required to enable then to come in contact with abutting discs 21 and 22. During the launching phase the gas generator 15 impinges on the rotor 1 which is thus set in rotation and as the abutting discs 21 and 22 are constructed as sliding bearings of relatively large area, the gyro rotor is only slightly braked during the acceleration. The elastic properties of the rings 16 and 17 and also the clearance d1,2 between the abutting discs and the gyro rotor axes when no acceleration takes place are coordinated in such a way that the bearings 3 and 4 can not be subject to any load beyond certain predetermined acceleration forces.

At the end of the launch phase the acceleration force decrease and the distances d1,2, d2,7 and d7,10 are restored as a result of the elastic properties of the rings 16 to 19 and the springs 20. As the contact surfaces 2.2 and 7.3, as well as 7.2 and 10.1, have not only a defined roughness but also a defined size, the acceleration force at which the gyro frames become free can be accurately determined in advance. If, therefore, the elastic mounting systems and the contact surfaces are suitably dimensioned and the gas generator 15 is caused to act for the appropriate period a special device for locking the gyro frames during the launching phase can be dispensed with.

Claims

CLAIMS 1. An acceleration resistant gyro for a missile with a cardanic gyro rotor suspension system secured in bearings to a frame which is mounted in bearings for rotation about a further axis, characterized by the bearins mounting the rotor and those mounting the frame having, at least: (a) one elastically mounted bearing and a small clearance between the parts mounted by the bearing, and (b) a rigid support bearing surface with a larger clearance between the parts mounted by the bearing whereby loading on the elastically mounted bearing is relieved at and above a predetermined acceleration force are exceeded. 2. A gyro in accordance with Claim 1,wherein further frames are provided and rotatable about axes at right angles in relation to each other and with at least one elastically mounted bearing, adjacent frames being provided on adjacent sides with contacting surfaces a defined distance apart when the gyro is not subject to acceleration forces. 3. A gyro in accordance with Claims 1 or 2, wherein a housing carries an outer frame rotatably mounted in at least one elastically mounted bearing, the housing and the frame having contacting surfaces which are a defined distance from one another when the gyro is not subject to acceleration forces. 4. A gyro in accordance with any one of Claims 1 to 3, wherein at least one of the support bearings is contructed as a plain sliding bearing. 5. A gyro in accordance with any one of Claims 1 to 4, wherein the elastically mounted bearings are movable in a radial and/or axial direction. 6. A gyro in accordance with any one of Claim 1 to 3, wherein the elastically mounted bearings have mountings of a tough elastic material. 7. A gyro constructed and arranged to function has been herein described with reference to and as shown in the accompanying drawings. 8. A missile incorporating a guidance or attitude control system having a gyro according to any preceding claim. New claims of amendments to claims filed on 11.4.83 Superseded claims 1 to 8 New or amended claims 1 to 13

1. A gyro arrangementfora missile with a gyro rotor rotationally mounted about a first axis in bearings to a frame, with the frame mounted in further bearings to a support member for rotation of the frame about a second axis, at least one of the bearings mounting the rotor being elastically supported with a clearance provided between a part of the rotor and part of the frame, the arrangement being such that loading applied to the elastically mounted bearing between the rotor and the frame in a direction across the clearance causes deformation of the elastic bearing support to reduce said clearance bringing the said parts into contact at and above a predetermined loading whereby further loading on the elastically mounted bearings is relieved.

2. A gyro arrangement for a missile with a gyro rotor rotationally mounted about a first axis in bearings to a frame, with the frame mounted in further bearings to a support member for rotation of the frame about a second axis, at least one of the bearings mounting the rotor being elastically supported, with a clearance provided between a part of the rotor and part of the frame and at least one of the bearings mounting the frame being elastically supported with a clearance provided between a part of the frame and a part of the support member, the arrangement being such that loading applied to the elastically mounted bearings between the rotor and the frame and the frame and support member respectively in a direction across the clearances causes deformation of the elastic bearing supports to bring the respective parts into contact at and above a predetermined loading whereby further loading on the elastically mounted bearings is relieved.

3. A gyro in accordance with Claim 2, wherein the frame has an outer surface with frictional areas thereon to contact opposed frictional areas on an inner surface of the support member, said areas defining the clearance between the frame and support members.

4. A gyro arrangement in accordance with Claim 1 or 2 or 3, wherein a further outer frame is provided rotatable about an axis at right angles to the first frame axis, said further frame comprising the support member and mounted to a housing through bearings.

5. A gyro in accordance with Claim 4, wherein the housing carries the outer frame rotatably mounted in at least one elastically supported bearing, the housing and the outer frame having contacting surfaces which are a defined distance apart when the gyro is not subject to acceleration forces, the bearing deflecting under load to bring the surfaces into contact.

6. A gyro in accordance with Claim 5, wherein the outer frame is supported by bearings deflecting in an axial direction of the bearing axis, an outer surface of the outer frame having frictional areas to contact opposed frictional areas on an inner surface of the housing, said areas lying radially of the rotatable mounting axis, and defining the contacting surfaces between the outer frame and housing.

7. A gyro in accordance with any preceding claim, wherein at least one of the bearings is a sliding bearing.

8. A gyro in accordance with any preceding claim, wherein the elastically supported bearings deflect in a radial and/or axial direction.

9. A gyro in accordance with an preceding claim, wherein the elastically supported bearings are mounted in a tough elastic material.

10. A gyro in accordance with any preceding claim, wherein the clearance between the part of the rotor and part of the frame is defined between the rotor shaft and a plate secured to the frame, the contacting surfaces of the shaft and plate forming a sliding bearing.

11. A gyro in accordance with any preceding claim, wherein the axes of the bearings mounting the rotor and the frames are contained in a plane normal to the direction of loading, the axes of the bearings mounting the second frame being parallel to the direction of loading.

12. A gyro constructed and arranded to fu nction as herein described with reference to and as shown in the accompanying drawings,

13. A missile incorporating a guidance attitude control system having a gyro according to any preceding claim.