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A Study of Parking Brake Cable Efficiency as Affected by Construction Type Paul Stoloff Brake Technical Lead Chrysler Group, LLC PAPER # 2011-01-2380.

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Presentation on theme: "A Study of Parking Brake Cable Efficiency as Affected by Construction Type Paul Stoloff Brake Technical Lead Chrysler Group, LLC PAPER # 2011-01-2380."— Presentation transcript:

1 A Study of Parking Brake Cable Efficiency as Affected by Construction Type Paul Stoloff Brake Technical Lead Chrysler Group, LLC PAPER #

2 Park Brake System Efficiency Cable Efficiency Force Efficiency Travel Efficiency Cable Testing Test Results Force Efficiency, Travel Efficiency and Work Efficiency Other Considerations Summary PAPER # Agenda

3 PAPER # Park Brake System Efficiency The mechanical efficiency of a parking brake system is determined by the sum of the losses of all components in the system Cables represent the greatest contribution to efficiency loss in a typical parking brake system. Since a parking brake lever delivers force and travel, work efficiency should be understood in order to optimize a system. Work is not simply the product of force and travel, but rather…

4 Input Force is limited by regulation and customer satisfaction Input travel is limited by packaging constraints and customer satisfaction Hence net work is limited. Since cables consume both force and travel efficiency, small improvements in cable performance can have significant affect on system performance Where to from here? PAPER # Cable Efficiency

5 Without data, you are just another person with an opinion, Anonymous With data, you are just another person with an analysis, Anonymous Independent data from different (biased) sources is insufficient to perform an analysis or draw any conclusions. Uniform testing is the proper method for gathering data. PAPER # Cable Testing

6 A simple cable test stand was developed and validated to measure input/output force and input/output travel under a fixed set of conditions. PAPER # Cable Testing

7 Cable samples from four leading cable suppliers were solicited. The following constructions were tested: PAPER # Cable Testing Flat Wire Conduit Twin Wire Conduit 1x19 Strand3 Samples 7x7 Strand3 Samples

8 The test stand was validated using one sample each of three different constructions that were expected to have measurable differences in performance. PAPER # Test Validation – Travel and Force Efficiency

9 Travel efficiency differences were clear and statistically valid. Force efficiency fell within a very narrow range and was repeatable. PAPER # Test Validation - Results

10 The testing was expanded to include all construction combinations from all suppliers; 48 pieces total. ANOVA analysis of the results showed a strong correlation for strand type. 1x19 Strand – 68.1% Mean 7x7 Strand – 61.1% Mean PAPER # Test Results – Travel Efficiency

11 ANOVA analysis of Force Efficiency revealed a moderate effect from Supplier, driven primarily by the poor performance of Supplier D and the good performance of Supplier A. PAPER # Test Results – Force Efficiency

12 Work efficiency was calculated using numerical integration. Of the sixteen combinations, the top eight were all 1x19 strand. Three of the top four were flat wire conduit. The worst performer had both the worst travel and worst force efficiency, compounding to create the worst overall performer. PAPER # Test Results – Work Efficiency 19%

13 Cable efficiency is not the only consideration in cable design. Others include Flexibility/Stiffness Cost Corrosion Resistance Supplier Strategy Application specific issues PAPER # Other Considerations

14 A method was demonstrated for quantifying parking brake cable performance. The method is simple, quick, repeatable, and reliable. Other variations of parts can be quickly evaluated and compared to previous results. This procedure provides the engineer the tools to remove the guesswork from cable selection. Proper selection of cable construction can result in significant improvements in parking brake system performance. PAPER # Summary


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