US2131614A - Brake drum - Google Patents

Description

Sept. 27, 1938. T CH SE 2,131,614

BRAKE DRUM Filed May 26, 1957 Patented Sept. 27, 1938 BRAKE DRUM Theron P. Chase, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application May 26, 1937, Serial No.144g98 Claims.

This invention relates to brakes and particularly to brakes for use on vehicles.

Specifically, the invention aims to provide an improved brake drum for use with vehicle wheels. 5 The main object of the invention is so to modify the conventional drum as to facilitate cooling when the drum is subjected to the heating effect of frictional engagement with the brake shoes.

A secondary, but nevertheless important, object is the accomplishment of the main object by a construction which will be simple and which will involve but little expense over the cost of a drum without provision for cooling.

Other objects and advantages will be understood from the following description.

In the drawing: Figure 1 is a view of the novel drum in elevation.

Figure 2 is a section on line 2-2 in Figure 1.

Figure 3 is a section on line 3--3 of Figure 1.

Figure 4 shows in transverse section a modification.

Referring to the several figures of the drawing, numeral 5 is a shoe-engaging annulus to which a closure disc I is secured. The disc I is shown with holes 9 for the passage of fastening means for attaching the drum to a vehicle wheel. Preferably, the disc is of sheet metal and has axially directed parts II by which the annulus, preferably of cast-iron, is secured to the disc in the act of casting. As shown in the drawing, the cast annulus has a radial flange l3 and extending axially along the outer face of the annulus there are cooling ribs l5, these ribs terminating at the flange.

At this point it may be said that such axial ribs are easily and inexpensively formed in the process of casting the drum. Taken by themselves such axial ribs are less efilcient for cooling than circumferential ribs for the reason that the direction of drum rotation is perpendicular to the ribs. Circumferential ribs are, however, far more expensive to form, requiring either a large expensive core it formed when casting the drum or requiring a thick wall which is to be subsequently machined to form grooves and ribs.

This invention makes use of the inexpensive axial ribs and to produce a circulation of air between the ribs there is provided a shallow cup- 50 shaped stamping H. The annular side wall IQ of this cup-shaped stamping overlies the ribs l5 and stops somewhat short of the flange 13. The

base 2| of the stamping extends over and is holes 9. There are a plurality of depressed portions 25 in part 2|, these depressed portions arranged in a circular series. These depressed portions only contactwith the disc I and the disc and the cup are riveted as at 21 or otherwise 5 secured together in these regions of contact.

When a vehicle with drums such as are described above is traveling, a current of air flows in the direction of the arrows entering between the base 2| of the shallow cup and the disc I as at 23. The air passes over the annulus 5 and between the ribs and escapes adjacent the flange I3. Such a drum is but a little more expensive to manufacture than a drum having no provision for cooling. There is no appreciable addill tional expense in casting the annulus with the axial ribs and the cost of the cup-shaped stamping is negligible. A drum so made is efliciently cooled. Such an expedient is of particular utility in vehicles now being produced where provision of high speed requires a provision for severe braking and where, too,'smaller wheels seriously restrict the size and braking area of the brake drum annulus.

Figure 4 shows a slight modification. Brake drum 5 with its ribs l5 remains unchanged. The stamping ll differs slightly from the stamping ll. Instead of being attached rigidly thereto by rivets 21, it is resiliently secured thereto with provision for a slight circumferential movement relative to the drum. In place of each of the rivets 21 shown in Figure 1 there may be secured to the disc I a retaining bolt 3|. The stamping I1 is provided with a plurality of openings to surround these bolts, the opening affording a limited degree of clearance as shown at 33. A coil spring 35 engages the depressed portion of the stamping I1 and has for its outer abutment a member 31 secured in any preferred way to the bolt 31. The resiliently restrained slight circumferential movement makes possible a frictional engagement between the wall of the member I1 and the ribs 15. This is intended to prevent brake drum squeals.

I claim:

1. A brake drum having a braking annulus and an attaching disc secured thereto, said annulus having axial ribs, and a cup-shaped stamping having a base positioned to form a space between said base and disc and having an annular wall overlying said ribs whereby the space between the base and the disc is in communication with the spaces between the ribs and the overlying annular wall.

2. A brake drum having a disc and a braking annulus, the latter of cast-iron with axial ribs on its outer surface, said disc and annulus being secured together; and a stamped cup having a base secured to but in spaced relation from said disc and having an annular wall overlying said ribs.

3. A brake drum having a braking annulus of cast-iron formed with a radial flange and a plurality of axially extending ribs on its outer surface, said ribs extending to said flange, an attaching closure member secured to said annulus for securing said annulus to a wheel, a stamped cup having a base secured to but in spaced relatior. from said closure member and also having an annular flange overlying said ribs and terminating a short distance from said flange.

4. A brake drum having a braking annulus and an attaching disc secured thereto, said annulus having axial ribs, and a cup-shaped stamping having a base secured to said disc and an annular wall overlying said ribs, the attachment of said stamping providing a limited relative circumferential movement between said stamping and said drum.

5. A brake drum having a braking annulus and an attaching disc secured thereto, said annulus having axial ribs, and a cup-shaped stamping having a base secured to said disc and an annular wall overlying said ribs, the attachment of said stamping comprising a plurality of said bolts carried by said disc, said stamping having enlarged openings surrounding said bolts, and yielding means holding said stamping against said disc.

THERON P. CHASE.

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