Title of Invention

A BRAKE DRUM FOR PREVENTING BRAKE NOISE IN A VEHICLE

Abstract

"A BRAKE DRUM FOR PREVENTING BRAKE NOISE IN A VEHICLE" A brake drum for preventing brake noise in a vehicle comprising a cylindrical portion (6) coaxially surrounding a cylindrical boss (5) fixed to an axle (9), and a connecting portion (7) formed integrally at one end of said cylindrical portion (6) for connection between one end of said boss (5) and one end of said cylindrical portion (6), wherein a ring-shaped thick wall portion (6c) is formed integrally with said cylindrical portion (6) and wherein the cylindrical portion (6) comprises a small diameter cylindrical portion (6a) connected at one end to the outer circumference of the connecting portion (7) and a large diameter cylindrical portion (6b) larger is diameter than the small diameter cylindrical portion (6a).

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "A BRAKE DRUM FOR PREVENTING BRAKE NOISE IN A VEHICLE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan, The following specification particularly describes the invention and the manner in which it is to be performed: The present invention relates to a brake drum for preventing brake noise in a vehicle. The present invention relates to a brake drum for vehicle comprising a cylindrical portion coaxially surrounding a cylindrical boss fixed to an axle, and a connecting portion formed integrally at one end of the cylindrical portion for connection between one end of the boss and one end of the boss and one end of the cylindrical portion, and particularly to an improvement in the brake drum for preventing brake noise. [0002] [Prior Art] Hitherto, a structure for preventing brake noise by attaching an elastic ring to the outer circumference of a brake drum has been disclosed, for example, in Japanese Utility Model Laid-open No. 63-193131 (1988), and also a structure for preventing brake noise by attaching a metallic ring to the outer circumference of a brake drum has been known. [0003] [Problems to be Solved by the Invention] In the prior art mentioned above, the structures in which an elastic ring or a metallic ring is attached have the drawback that not only the number of component parts is increased but also an assembly step for the ring is needed, leading to a rise in cost. [0004] The present invention has been made in... consideration of the above-mentioned situations, and it is an object of the invention to provide a brake drum for vehicle by which a brake noise preventing effect can be obtained while enabling reductions in the number of component parts and the number of assembly steps. [0005] [Means for Solving the Problems] In order to attain the above object, the invention as set forth in claim 1 is characterized in that, in a brake drum for vehicle including a cylindrical portion coaxially surrounding a cylindrical boss fixed to an axle, and a connecting portion formed integrally at one end of the cylindrical portion for connection between one end of the boss and-one end of the cylindrical portion, a ring-shaped thick wall portion is formed integrally with the cylindrical portion. [0006] According to such a constitution as this, the thick wall portion formed at the cylindrical portion enhances rigidity of the cylindrical portion, whereby vibration of the cylindrical portion can be restrained and brake noise can be prevented. In addition, since the thick wall portion is formed integrally with the cylindrical portion at the time of forming the brake drum, the number of component parts can be reduced and the number of assembly steps can be reduced because an assembly step for a ring is unnecessitated, as compared to the prior art where a ring separate from a brake drum is attached to the outer circumference of a cylindrical portion. [0007] The invention as set forth in claim 2 is characterized, in addition to the constitution of the invention of claim 1, in that the boss is formed integrally with the connecting portion. According to such a constitution as this, a working step of finishing the inside surface of the cylindrical portion after welding thereof to the boss—i-s~ unnecessary and the number of working steps can be reduced, as compared to the prior 1 art where the connecting portion of a brake drum is welded to the boss. Namely, where the connecting portion v is welded to the boss, the welding heat may produce strains in the cylindrical portion and the boss, and a working step of correcting the strain is needed. On the other hand, where the boss and the connecting portion are formed as one body wi th each other, such a'strain can be prevented from being generated and the number"of working steps can be reduced. According to the present invention there is provided a brake drum for preventing brake noise in a vehicle comprising a cylindrical portion coaxially surrounding a cylindrical boss fixed to an axle, and a connecting portion formed integrally at one end of said cylindrical portion for connection between one end of said boss and one end of said cylindrical portion, wherein a ring-shaped thick wall portion is formed integrally with said cylindrical portion and wherein the cylindrical portion comprises a small diameter cylindrical portion connected at one end to the outer circumference of the connecting portion and a large diameter cylindrical portion larger is diameter than the small diameter cylindrical portion. [BRIEF DESCRIPTION OF THE DRAWINGS) [FIG. 1] A vertical sectional view of a wheel with a brake drum; [FIG. 2] Views sequentially showing steps of forming by forging of the brake drum. [Mode for Carrying Out the Invention] Now, a mode of carrying out the invention will be described based on one embodiment of the invention illustrated by the attached drawings. [0009] FIGS. 1 and 2 illustrate one embodiment of the invention, wherein PIG. 1 is a vertical sectional view of a wheel comprising a brake drum, and FIG. 2 sequentially shows steps of forming a brake drum by forging. ' [00010] First, in FIG. 1, the outer circumference of a spoke 3 is welded to a rim 2 on which a tire 1 is mounted, and the inner circumference of the spoke 3 is welded to the outer circumference of a brake drum 4 according to the invention. [00011] The brake drum 4 comprises, as one body, a cylindrical boss 5 fixed to an axle 9, a cylindrical portion 6 coaxially surrounding the boss 5, and a connecting portion 7 connecting between one end of the boss 5 and one end of the cylindrical portion 6, and a ring-shaped thick wall portion 6c is formed integrally with the cylindrical portion 6. [00012] The brake drum 4 as above may, for example, be formed by forging through the steps shown in FIG. 2. In the forming by forging, first, a blank member 11 is prepared as shown in FIG. 2 (a) . As material of the blank member 11, light metals such as aluminum alloys, titanium alloys and the like, carbon steel, stainless steel, copper alloys and so on can be used preferably. The blank member 11 is desirably annular in shape. [00013] The blank member 11 is worked by forging through sequentially subjecting it to the steps illustrated by PIGS. 2 (b) to 2(g). First, the blank member 11 is drawn to obtain a primary formed body 12 with a bell-shaped cross section as shown in FIG. 2(b). [00014] The primary formed body 12 is subjected to upset working, whereby a secondary formed body 15 having a semi - finished boss portion 13 and a semi - finished cup portion 14 is obtained as shown in FIG. 2(c), and the secondary formed body 15 is subjected to overhang working By this, as shown in FIG. 2(d), there is obtained a tertiary formed body 18 having a semi - finished boss portion 16 and a semi - finished cup portion 17 in such a shape that the semi - finished boss portion 13 -and the semi - finished cup portion 14 are stretched out like overhang. [00015] The tertiary formed body 18 is subjected to flattening of an end face of the semi-finished boss portion 16 and ironing of the semi - finished cup portion 17. By this, as shown in FIG. 2 (e), there is obtained a fourth-degree formed body 21 having a semi - finished boss portion 19 and a semi-finished cup portion 20, with a thick wall portion 20a formed at an opening end portion of the semi - finished cup portion 20. [00016] The fourth-degree formed body 21 is subjected to sizing working in which the semi-finished boss portion 19 is reduced in diameter and inside diameter portion of the semi - finished cup portion 20 is ironed. By this, as shown in FIG. 2(f), there is obtained a semi-product 4' corresponding substantially to the brake drum 4 . The semi-product 4' comprises, as one body, the cylindrical boss 5, the cylindrical portion 6 coaxially surrounding the boss 5, and the connecting portion 7 for connection between one end of the boss 5 and one end of the cylindrical portion 6. The cylindrical portion 6 comprises a small diameter cylindrical portion 6a connected at one end to the outer circumference of the connecting portion 7 and a large diameter cylindrical portion 6b larger in diameter than the small diameter cylindrical portion 6a, which are coaxially connected to each other through a ring-shaped thick wall portion 6c formed larger in thickness than the small diameter cylindrical portion 6a and the large diameter cylindrical portion 6b. Namely, the ring-shaped thick wall portion 6c is formed as one body with the cylindrical portion 6. [00017] The inside surface of the boss 5 in the semi¬product 4' is subj ected to working by spline forming, whereby there is obtained the brake drum 4 in which spline grooves 10 for spline connection with the axle 9 are formed in the inner circumference of the boss 5, as shown in FIG. 2 (g) . [00018] Next, the operation or effect of the embodiment will be described. Since the ring-shaped thick wall portion 6c is formed integrally with the cylindrical portion 6 of the brake drum 4, the thick wall portion 6c enhances the rigidity of the cylindrical portion 6, whereby vibration of the cylindrical portion 6 can be restrained and brake noise can be prevented Further, since the thick wall portion 6c is formed integrally with the cylindrical portion 6 at the time of forming the brake drum 4, the number of component parts can be reduced and the number of working steps can be reduced because an assembly step for a ring is unnecessary, as compared with the prior art where a ring separate from the brake drum 4 is attached to the outer circumference of the cylindrical portion 6. [00019] In addition, since the connecting portion 7 and the boss 5 of the brake drum 4 are formed as one body, the number of working steps can be reduced because finishing of the inside surface of the cylindrical portion 6 after welding to the boss is unnecessary, as compared to the prior art where the connecting portion 7 of the brake drum 4 is welded to the boss, and working accuracy of the spine grooves 10 provided in the inside surface of the boss 5 can be maintained at a high level. Namely, where the connecting portion 7 is welded to a boss, a step for correcting strains generated in the cylindrical portion 6 due to welding heat may be required, and the working accuracy of the spline grooves 10 in the inside surface of the boss 5 may be lowered. On the other hand, where the boss 5 and the connecting portion 7 are formed as one body, a step for correcting such strains is not needed, whereby the number of working steps can be reduced, and the working accuracy of the spline grooves 10 can be maintained at a high level. [00020] While the embodiment of the invention has been described, the invention is not limited to the embodiment and various design modifications can be made without departure from the invention as set forth in the claims. [00021] [Effects of the Invention] As described above, according to the invention as set forth in claim 1, the thick wall portion enhances the rigidity of the cylindrical—portion, whereby vibration of the cylindrical portion can be restrained and brake noise can be prevented. In addition, since the thick wall portion is formed integrally with the cylindrical portion at the time of forming the brake drum, the number of component parts can be reduced, and the number of assembly steps can be reduced because an assembly step for a ring is unnecessary, as compared with the prior art where a ring separate from the brake drum is attached to the outer circumference of the cylindrical portion. [00022] Besides, according to the invention as set forth in claim 2, the number of working steps can be reduced. Explanation of Symbols] 4: brake drum 5: boss 6: cylindrical portion 6c: thick wall portion 7; connecting portion 9: axle We Claim: 1. A brake drum for preventing brake noise in a vehicle comprising a cylindrical portion (6) coaxially surrounding a cylindrical boss (5) fixed to an axle (9), and a connecting portion (7) formed integrally at one end of said cylindrical portion (6) for connection between one-end-of-said boss~(5) and one end of said cylindrical portion (6), wherein a ring-shaped thick wall portion (6c) is formed integrally with said cylindrical portion (6) and wherein the cylindrical portion (6) comprises a small diameter ^cylindrical portion (6a) connected at one end to the outer circumference of the connecting portion (7) and a large diameter cylindrical portion (6b) larger is diameter than the small diameter cylindrical portion (6a). 2. A brake drum for vehicle as claimed in claim 1, wherein said boss (5) is formed integrally with said connecting portion (7). 3. A brake drum for vehicle substantially as herein described with reference to the accompanying drawings. Dated this the 12th day of March, 2001 ABSTRACT "A BRAKE DRUM FOR PREVENTING BRAKE NOISE IN A VEHICLE" A brake drum for preventing brake noise in a vehicle comprising a cylindrical portion (6) coaxially surrounding a cylindrical boss (5) fixed to an axle (9), and a connecting portion (7) formed integrally at one end of said cylindrical portion (6) for connection between one end of said boss and one end of said cylindrical portion (6), wherein a ring-shaped thick wall portion (6c) is formed integrally with said cylindrical portion (5)and wherein the cylindrical portion (6) comprises a small diameter cylindrical portion (6a) connected at one end to the outer circumference of the connecting portion (7) and a large diameter cylindrical portion (6b) larger is diameter than the small diameter cylindrical portion (6a).

Documents:

238-mum-2001-abstract(12-3-2001).doc

238-mum-2001-abstract(12-3-2001).pdf

238-mum-2001-abstract(amended)-(9-12-2005).pdf

238-mum-2001-abstract(granted)-(7-6-2006).doc

238-mum-2001-abstract(granted)-(7-6-2006).pdf

238-mum-2001-cancelled pages(9-12-2005).pdf

238-mum-2001-claims(12-3-2001).doc

238-mum-2001-claims(12-3-2001).pdf

238-mum-2001-claims(amended)-(9-12-2005).pdf

238-mum-2001-claims(granted)-(7-6-2006).doc

238-mum-2001-claims(granted)-(7-6-2006).pdf

238-mum-2001-correspondence(16-1-2006).pdf

238-mum-2001-correspondence(ipo)-(24-8-2006).pdf

238-mum-2001-description(complete)-(12-3-2001).pdf

238-mum-2001-description(complete)-(granted)-(7-6-2006).pdf

238-mum-2001-drawing(12-3-2001).pdf

238-mum-2001-drawing(granted)-(7-6-2006).pdf

238-mum-2001-form 1(12-3-2001).pdf

238-mum-2001-form 1(9-12-2005).pdf

238-mum-2001-form 13(9-1-2006).pdf

238-mum-2001-form 18(22-2-2005).pdf

238-mum-2001-form 2(12-3-2001).doc

238-mum-2001-form 2(12-3-2001).pdf

238-mum-2001-form 2(granted)-(7-6-2006).doc

238-mum-2001-form 2(granted)-(7-6-2006).pdf

238-mum-2001-form 2(title page)-(12-3-2001).pdf

238-mum-2001-form 2(title page)-(granted)-(7-6-2006).pdf

238-mum-2001-form 3(12-3-2001).pdf

238-mum-2001-form 3(9-12-2005).pdf

238-mum-2001-form 4(16-1-2006).pdf

238-mum-2001-form 5(12-3-2001).pdf

238-mum-2001-petition under rule 137(9-12-2005).pdf

238-mum-2001-petition under rule 138(9-12-2005).pdf

238-mum-2001-power of authority(29-6-2001).pdf

238-mum-2001-specification(amended)-(9-12-2005).pdf