Shim structure for brake squeal attenuation
View Patent ↗A shim structure is provided for damping vibration and attenuating noise in a brake system. The brake system includes a forcing member operable to urge a friction member against a rotating member to slow or stop the same. The shim structure includes a shim body that is adapted to be interposed within the brake system. The shim body includes one or more tabs that are configured to oscillate out-of-phase with vibrations generated by the brake system during urging of the friction member against the rotating member to thereby dissipate vibrational energy generated by the brake system. The dimensions, orientation, and/or location of each tab are selected or engineered to provide predetermined levels of vibration and noise attenuation. A mass may be attached to each tab. The geometry, location, and/or size of each mass may be selectively modified to provide predetermined levels of vibration and noise attenuation.
1. A shim structure for use in a brake system having a forcing member operable to urge a friction member against a rotating member to slow or stop the rotating member, the shim structure comprising:
a shim body adapted to be interposed within the brake system, said shim body having at least one tab that is configured to oscillate out-of-phase with vibrations generated by the brake system during urging of the friction member against the rotating member to thereby dissipate vibrational energy generated by the brake system;
wherein said at least one tab is defined within said shim body by at least one groove extending through the shim body, said at least one tab extending substantially coplanar with said shim body;
at least one mass at least partially surrounded by said at least one groove, wherein said at least one mass is not substantially co-planar with said at least one tab; and
a layer of adhesive extending between said shim body and a backing plate of the friction member to bond said shim body to the backing plate of the friction member, wherein said at least one tab is characterized by an absence of an adhesive layer thereon.
2. The shim structure of claim 1 , wherein at least one of the dimensions, orientation, and positioning of said at least one tab is engineered to provide a predetermined level of vibration and noise attenuation.
3. The shim structure of claim 1 , wherein said at least one tab extends from an outer peripheral edge of said shim body.
4. The shim structure of claim 3 , wherein said at least one tab extends substantially coplanar with said shim body.
5. The shim structure of claim 3 , wherein said at least one tab extends substantially orthogonally from said outer peripheral edge of said shim body.
6. The shim structure of claim 3 , wherein said at least one tab is oriented substantially flush against said shim body.
7. The shim structure of claim 1 , wherein at least one of the geometry, positioning, and size of said at least one mass is engineered to provide a predetermined level of vibration and noise attenuation.
8. The shim structure of claim 1 , wherein said at least one mass is attached to an outer surface of said at least one tab that is distal from the friction member.
9. The shim structure of claim 1 , wherein said at least one mass is attached to an inner surface of said at least one tab that is proximate to the friction member.
10. The shim structure of claim 9 , wherein said at least one mass is disposed substantially inside a complementary hole formed in a backing plate of the friction member.
11. The shim structure of claim 10 , wherein an outer peripheral surface of said at least one mass is configured to frictionally engage an inner peripheral surface of said complementary hole.
12. The shim structure of claim 10 , wherein an outer peripheral surface of said at least one mass includes a coating thereon configured to frictionally engage said at least one mass with an inner peripheral surface of said complementary hole.
13. The shim structure of claim 1 , further comprising:
a layer of viscoelastic material extending between and bonded to said shim body and a backing plate of the friction member.
14. The shim structure of claim 1 , wherein said shim body and said at least one tab consist essentially of a substantially flat single-piece plate member formed from a high temperature tempered metallic material.
15. The shim structure of claim 1 , wherein said at least one groove is substantially C-shaped.
16. A shim structure for damping vibration and attenuating noise in a motor vehicle disc brake assembly having a brake pad with a backing plate supporting a friction lining thereon, and a piston member operable to urge the brake pad against a brake rotor to thereby slow or stop the vehicle, the shim structure comprising:
a shim body adapted to be interposed between the backing plate and the piston member, said shim body having at least one tab that is configured to counterbalance resonance instability generated by the disc brake assembly during urging of the brake pad against the brake rotor to thereby dissipate vibrational energy generated by the brake system;
wherein said at least one tab is selectively positioned relative to said shim body to be immediately adjacent a predefined location of the brake pad having a predetermined vibrational amplitude or frequency;
wherein said at least one tab is defined within said shim body by at least one groove extending through the shim body, said at least one tab extending substantially coplanar with said shim body;
at least one mass at least partially surrounded by said at least one groove, wherein said at least one mass is not substantially co-planar with said at least one tab; and
a layer of adhesive extending between said shim body and a backing plate of the friction member to bond said shim body to the backing plate of the friction member, wherein said at least one tab is characterized by an absence of an adhesive layer thereon.
17. A disc brake assembly for a motorized vehicle having at least one wheel, the brake assembly comprising:
a rotor operatively mounted with respect to the at least one wheel to transmit braking forces thereto;
a housing member operatively mounted to the vehicle proximate to said brake rotor;
at least one brake pad operatively disposed within said housing member and configured to frictionally engage said brake rotor;
a piston member movably disposed within said housing member and operable to selectively effect the frictional engagement between said at least one brake pad and said rotor; and
a shim member interposed between said at least one brake pad and said piston member, said shim member having at least one tab that is configured to oscillate out-of-phase with vibrations generated by the disc brake assembly during urging of the brake pad against the rotor to thereby dissipate vibrational energy generated by the brake system;
wherein said at least one tab is defined within said shim body by at least one groove extending through the shim body, said at least one tab extending substantially coplanar with said shim body;
at least one mass at least partially surrounded by said at least one groove, wherein said at least one mass is not substantially co-planar with said at least one tab; and
a layer of adhesive extending between said shim body and a backing plate of the friction member to bond said shim body to the backing plate of the friction member, wherein said at least one tab is characterized by an absence of an adhesive layer thereon.