Patent GB-746970-A (GB)
Title: Improvements in or relating to devices for the circulation of fluid
Inventor: BARRAQUE ALFRED DOMINIQUE
IPC: F16D65/827
Filed: 1953-12-03
Abstract: 746,970. Brake drums. SOC. ANON. FRANCAISE DU FERODO. Dec 3, 1953, No. 33703/53. Class 103 (1). [Also in Groups XXII, XXIV, XXVI and XXXI] A brake drum is cooled by an axial-flow fan, the impeller blades of which are formed from an annular undulated strip, each undulation of which has its general medial rectilinear direction inclined with respect to the axis of rotation but extending substantially in a plane parallel to the axis. Fig. 3 shows an automobile brake drum 10 which is cooled by a fan comprising an undulated ring 17. The direction of flow through each undulation makes an angle of between 20 and 60 degrees and preferably between 30 and 50 degrees with the axis of the drum. The undulations may be formed by folding and bonding a flat strip, the ends of which are joined by soldering by rivets 22. Material may be deposited or on the ring 17 to counterbalance the rivets 22. The ratio of the radius of the crests 18 to that of the crests 19 lies between 1 to 20 and 1 to 1, and is preferably between 1 to 10 and 1 to 2, say 1 to 4. The ring 17 is sprung over a chamfer 13, Fig. 8, on to the cylindrical surface 14 of the drum and held between annular shoulders 15, 25. The shoulder 25 may be omitted, as in Fig. 10. Instead of being cylindrical, the surface 14 may be conical or hyperboloidal. If formed from initially flat material with parallel sides, the undulated ring 17 has slightly sinuous edges, as shown in Fig. 10, but the ring may be shaped to provide edges lying in planes perpendicular to the axis of the drum. Fig. 10 also shows a modified form of the ring 17, having an extension 26 beyond the shoulder 15. The ring 17 may be formed from flat strip having oblique slots 31, Fig. 13, communinicating with slits 32. After formation of the undulations, the edges of each slot 31 are joined together to form crests 28, Fig. 10, which clear the shoulder 15. In another modification, Fig. 15, the material beyond the slits 32 is brought down against a cylindrical rebate 150 to assist in holding the ring 17 on the brake drum 10. The ring 17 may be formed with bayonet slots which engage bosses on the rim of the brake drum 10, a locking screw preferably being provided on each boss. In the embodiment shown in Fig. 22, holes 54 are provided in the wheel disc 48, through which air is drawn by the undulated ring 17. Air entering the brake drum 10 by way of holes 50, 51, 52 passes through holes 53 to join the main stream of air passing through the undulations. In addition, air is drawn out through the gap between the brake drum 10 and a stationary disc 43 by the ejector effect of air discharged at 44. Fan blades 55 may be provided. The holes 53 may be omitted. In a modification, the direction of air flow is reversed, and the holes 50, 51, 52 are replaced by holes in the disc 43. In a further embodiment, Figs. 24 and 25, air enters a stationary shroud 64 at 66 and passes around the annular space 68 between the brake drum 61 and the wheel 60 and is discharged by the undulated ring 62 into a second stationary shroud 65, from which it is expelled at 70. In the embodiment shown in Fig. 26, the lower half of the stationary disc 71 is extended to obstruct the flow of air through the undulated ring 62. Fig. 28 shows an undulated ring 101 applied to the internal periphery of a wheel disc 48. The main stream of air flows through holes 104, entraining subsidiary flows through holes 106, 107, and through the space 105 around the brake drum 10. Fig. 35 shows a brake pulley, i.e. a pulley which can rotate relative to the transmission belt 142, the belt acting as a brake lining. The pulley is cooled by an undulated ring 145. The ring 145 is carried by a cylindrical shell 148 which in turn is carried by fingers 147 projecting from the brake disc. In a modification, the fingers 147 extend from the rim 140 and the shell 148 is omitted.