Patent Application
20070056816
The subject invention relates to a brake component assembly with a friction lining supported on a plate with a sealing barrier formed between the friction lining and plate.
Brake shoe and pad assemblies utilize a friction lining that is supported on a plate, which is often referred to as a brake table. Traditionally, an adhesive or a plurality of fasteners is used to attach the friction lining to the brake table. In response to a braking command, an actuator moves the brake shoe or pad assembly such that the friction lining contacts a rotating brake component, such as a drum or disc.
Corrosion or rust can develop at an interface between the brake table and friction lining. Over time this rust or corrosion can expand or grow, which can cause a separation of the friction lining from an outer surface of the brake table. This can deform the friction lining from its intended shape resulting in less efficient braking. Further, this expansion force, in combination with an attachment force of the adhesive or fastener, acting in an opposing direction from the expansion force, can cause the friction lining to crack. This can accelerate wear of the friction lining. Further, governmental restrictions can require a vehicle with cracked linings to be taken out of service. In this situation the friction linings are required to be changed before wear life is met.
It is known to provide a double-sided adhesive liner between the friction lining and brake table to protect against corrosion. This double-sided adhesive liner adheres to both the friction lining and the brake table. However, once a friction lining has worn, it is difficult and time consuming to replace the worn lining with a new friction lining due to the double-sided adhesive liner.
Thus, there is a need for a brake shoe or pad assembly that provides a sealing barrier to prevent corrosion, and which allows for easy replacement of new friction linings, as well as overcoming other deficiencies in the prior art.
A brake pad or shoe assembly includes a sealing bearing that prevents corrosion between a friction lining and a support plate. A liquid material is initially applied to at least one of the support plate and friction lining. After application of the liquid material, the friction lining is fastened to the brake table with a plurality of fasteners. The liquid material subsequently forms the sealing barrier.
In one example, the liquid material is a silicon based material that can be sprayed or rolled onto either or both of the support plate and friction lining. In another example, the liquid material is applied as a bead of material on either or both of the support plate and friction lining.
In one example, the support plate is dipped into the liquid material such that the support plate is substantially coated with the liquid material.
In another example, the sealing barrier comprises a flexible gasket that is positioned between the support plate and the friction lining. The sealing barrier is made from a resilient rubber material or cork, for example, and is solely used to provide a sealed interface between the friction lining and the support plate. Fasteners are then used to secure the friction lining to the support plate.
The sealing barrier is solely relied upon to provide a sealed interface between the friction lining and the support plate. Fasteners are relied upon to secure the friction lining to the support plate. This configuration allows worn friction linings to be easily and efficiently replaced. The worn friction lining is removed from the support plate, liquid material is applied as discussed above, and a new friction lining is secured to the support plate.
In addition to allowing worn friction linings to be easily replaced, the subject sealing barrier prevents rust/corrosion from forming between the friction lining and support plate, which results in improved brake performance and longer friction lining life.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A brake assembly 10 is shown in
Each brake shoe 12 is fixed at one end with an anchor pin 18. An actuator 20 is associated with an opposite end of each brake shoe 12 and is used to move the brake shoes 12 into engagement with a rotating brake component such as a brake drum (not shown), for example. In the example shown, the actuator 20 comprises an S-cam that moves the brake shoes 12 in response to a brake command. Other types of actuators 20 could also be used such as wedges or hydraulic cylinders, for example. Resilient members 22 assist in returning the brake shoes 12 to a non-applied position, as known.
One brake shoe 12 is shown in greater detail in
A plurality of fasteners 36 is used to secure the friction lining 16 to the brake table 14. In the example shown, rivets are used, however, other types of fasteners could also be used. The fasteners 36 are relied upon to provide a sufficient attachment force between the friction lining 16 and the brake table 14.
A sealing barrier 40 is formed between the friction lining 16 and the brake table 14 to prevent ingress of contaminants, which leads to the occurrence of rust and corrosion. The sealing barrier 40 comprises a sealant that, in additional to sealing, provides an additional benefit of filling in any surface irregularities in the friction lining 16 and/or the brake table 14 generated during manufacturing. The sealing barrier 40 is primarily relied upon to provide a sealing effect; however, the sealant may additionally provide some adhesion between the brake table 14 and friction lining 16. However, any adhesion provided by the sealant is not relied upon for securement purposes. The fasteners 36 are solely relied upon to provide sufficient securement between the brake table 14 and friction lining 16. Examples of the sealing barrier 40 are shown in
In the example shown in
The liquid material is at least one of a sealant and adhesive that may or may not include color additives. In one example, the liquid material is a silicon based material that is sprayed onto a painted or unpainted surface on the brake table 14. After the liquid has dried, the sealing barrier 40 is formed and will seal moisture and contaminants out while still being able to flex in response to heating/cooling, and can flex in response to brake torque deflections.
The example shown in
The example shown in
In the example shown in
In the example shown in
For any of the embodiments discussed above, the brake shoe 12 can be easily re-fitted with a new friction lining once a friction lining has worn to a level such that the friction lining needs to be replaced. To re-fit the brake shoe 12, a worn friction lining is removed from the brake table 14. A sealing barrier 40 is applied to at least one of the outer surface 28 of the brake table 14 and the new friction lining, and then the new friction lining is fastened onto the original brake table 14. The sealing barrier 40 can be applied in any one of the manners discussed above.
The subject sealing barrier 40 prevents moisture intrusion and rust/corrosion from forming between the friction lining 16 and brake table 14, which results in improved brake performance and longer friction lining life. Further, the subject sealing barrier 40 allows the brake shoe 12 to be easily re-fitted with new friction linings. The sealing bearing 40 is primarily relied upon to provide a sealing feature but may provide some adhesion between the brake table 14 and the friction lining 16. The fasteners 36 are solely relied upon to secure the friction lining 16 to the brake table. If the sealing barrier 40 does provide some adhesion, residual portions of the sealing barrier may have to be removed from the brake table 14 prior to re-fitting the brake table 14 with new friction linings.
It should be understood that while the sealing barrier 40 is shown in the figures as being associated with a brake shoe for a drum brake assembly, the sealing barrier could be used with pad or shoe assemblies for other types of brakes.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
