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KEYENCE Contact Sensor Prevents Automobile Part Defects


A tier two automotive supplier handles braking needs for cars and light duty pickups. Typical parts of a hydraulic disk braking system include a power booster, master cylinder, brake lines, and calipers to apply pressure to the rotors to stop the vehicle. The power booster is a component designed to amplify the mechanical energy inputted by the brake pedal fed into the master cylinder. It takes hundreds of pounds of force on the master cylinder piston to stop a vehicle quickly, and a booster makes it possible for a driver to accomplish this with little effort.

The booster examined in this study is constructed of two halves and the use of a “diaphragm” to seal the two halves. It is essentially a rubber gasket that lines the two halves as they come together during assembly. The diaphragm maintains an air tight seal between the two halves and allows for some flexibility of the booster under load.

The Problem

During assembly, if the diaphragm is not seated in the right place, the two halves will not seal properly creating a defective product. One half with a smaller diameter fits inside a larger one with the gasket acting as a cushion in between. During seating , a diaphragm can become “pinched” during the process sometimes creating tears and/or not allowing for the necessary tight seal required by the part.

Sensing the diaphragm is difficult with conventional methods due to the change in color of the rubber and powder coating that can often occur. There is a noticeable height change when the gasket is present , but since the rubber is flexible it can vary from 2-5 millimeters off the base of the unit. The diaphragm need s to be sensed in several locations to ensure that it is seated in critical areas. Space and mounting locations are limited.

The Solution

After consulting the customer, KEYENCE proposed a contact solution using the GT-A10L series sensor head. These heads provide the accurate sensing required and help push the rubber into a repeatable position so it can be checked accurately. The air actuated heads can make the necessary checks, and retract out of the way, all with minimal programming and setup. GT series sensor heads are also extremely compact and able to fit into the necessary spaces required.

The Results

When a booster is presented, air would be fed into the GT heads and they would extend to touch their target. Using the low stress to ensure safe handling of the diaphragm, the GT would then output either a hi/low/go signal discretely out of its amplifier. The simple setup allowed for easy integration into the existing equipment and provided this customer the ability to provide a quality product with confidence. KEYENCE has saved this supplier time and money with an easy to set up solution that eventually makes its way to the cars and trucks driven today.

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