GB617474A - Improvements relating to gas-turbine engines - Google Patents

Abstract

617,474. Coupling turbine discs. JUDSON, C. A., READ, J. R., and HUNTER, P. E. Oct. 2, 1946, No. 29429. [Class 80 (ii)] [Also in Groups XXV and XXVI] In a turbine rotor assembly comprising two or more axially-spaced discs, at least one disc is attached to an adjacent disc by a bolt member which passes through a central bore in one disc and engages a threaded part on the other and abutment means are provided to axially space the discs at a radius greater than that of the bolt member. The abutment means may be a separate spacer ring. A second abutment at a smaller radius than the first may also be provided. The turbine disc 20, Fig. 2, is attached to the turbine disc 19 by a bolt member 34 which engages a nut 33 spigoted and bolted to the flange 32 of the disc 19. The discs are spaced axially by a T-shaped member 35 which encircles the bolt member. A spigot 41 on the disc 20 is received in a recess of the nut 33 and abuts against a washer 42 accommodated in the bottom of the recess. This forms a second abutment between the two discs at a smaller radius than the first and by means of selective assembly of the T-shaped member 35 and the washer 42 it is possible to adjust the load between the discs and the member 35. A ring 44 bolted to the flange 46 has an axial flange formed with teeth which engage corresponding teeth on the bolt head 43 to prevent the bolt 34 slacking off. The leg of the T-shaped member 35 is formed at its inner radius with splines 38 which engage corresponding formations on the flanges 32 and 39 of the discs to assist in the transmission of torque from one disc to the other. The peripheral flange of the T-shaped member 35 may be frusto-conical in form and have its outer surface stepped to co-operate with a similarly shaped flange 37 on the sealing diaphragm between the discs. The T-shaped member is located on the nut 33 by lugs 40. The disc 19 is bolted to the shaft 12 and a sleeve 29 on which the bearing 30 is mounted. The sleeve 29 is formed with a flange in which are cut splines which engage splines cut in the flanges 27, 28 of the disc 19 and shaft 12. The bolt member may be hollow and used as a passage for the supply of cooling air as described and claimed in Specification 617,473, [Group XXVI]. According to the Provisional Specification the head of the bolt may be provided with a flange drilled with a circular series of holes which are used in conjunction with a series of holes in a flange of one of the discs to prevent rotation of the bolt. The holes are drilled so as to give a vernier adjustment.