The Art of Suspension DDA Valve
Dynamic Damping Adjustment DDA The Tractive dampers are equipped with the Tractive DDA Valve (Dynamic Damping Adjustment ). Damping values are dictated from the suspension parameters and the need of the application rather than dictated by the principle. The Damping characteristics of shock absorbers with DDA technology are determined by the main shim stack on a piston with same tuning possibilities as known from other high end aftermarket shock absorbers. The DDA valve is based on a dynamically balanced solenoid valve. When the valve is energized, the bypass opens proportionally to applied current. At full current the Soft curve is achieved. The cross-section of the electromagnetic valve is shown during a rebound stroke (left) and compression stroke (right) to visualize the flow direction of the hydraulic fluid. As commonly seen with hydraulic dampers, rebound and compression flow are separated by different channels in the piston (1). Their respective shim stacks and preload determine the flow hydraulic fluid as function of pressure. The valve allows for the hydraulic fluid to flow through the center of the upper part of the spindle and disperse around the valve body. The valve is normally closed by a set springs (3). By applying a voltage on the solenoid, a current will be generated through the coil (4) as function of its resistance and inductivity
Dynamic Damping Adjustment DDA Continuously variable damping, any damping curve shape feasible: progressive, linear and digressive Fast, linear and proportional damping response to control input Wide dynamic range Not prone to stability and wear/leakage issues Compression and Rebound in a natural relation, can be tuned the traditional way. Possibly in combination with additional soft valving. Shock absorbers can be serviced or tuned easily. When current is off because of broken cables, damping is hard => this failsafe situation yields a safe situation, maybe uncomfortable, but safe. Linear range digressive range
DDA valve adjustment range: FIRM curve The DDA solenoid valve controls a bypass oil flow through the piston rod over the piston. At zero current the bypass is closed ( normally close or NC). The damping force is generated over the main piston only. The character and level of the FIRM damping curves are 100% determined by the shim stack on the main piston: rebound shim stack, compression shim stack.
DDA valve adjustment range: DAMPING RANGE At full current (2.0 Amp) the bypass is fully open. The oil still flows partly over the main piston, but the bypass through the valve results in the SOFT curves. Intermediate currents (0-2Amp) result in intermediate curves
DDA valve adjustment range: DAMPING CONTROL Because of very short step response, very low hysteresis and high reproducibility, the full damping range is available for continuous damping control. The DDA valve is used for OEM, aftermarket and racing applications in motorbike, snowmobile, ATVand car applications.
Design process, magnetic force calculations
Design process, fluid flow, pressure and force calculations PATENTED TECHNOLOGY Multiple Fluid Flow and Fluid Force calculations to balance the slider at most critical situations in order to eliminate self adjustment and valve instability.
Linearity calculations Flow versus Current Flow (mm2) Current (A)
Tractive direct proportional electro magnetic valve Dynamic Damping Adjustment valve valve is mounted on piston rod protected against outside influences controls directly rebound and compression oil flow in one valve Specifications Standard configuration valve normally closed (NC) Optional normally open, failsafe, tuneable soft setting Damping range from firm to soft: 0,5-2 A Power consumption 5 10 Watt Step response time 6 to 8 ms Range 0 10 kndamping force Package: 45 mm length effective, fits tubes >= 36 mm Ready for use in mono tube, emulsion and twin tube shock absorbers Part of the shock, therefore easy to install and package User friendly interface designed for a temperature range of -30 to 120 degrees Celsius R(Ohm) L(mH-120Hz) L(mH-1Khz) Bilstein ( Nissan GTR& Porsche ) 2.5 12.8 5.45 Tractive SAF series 3.2 5.7 1.5 Tenneco Motorcycle serie 3.0/3.1 13.7/13.4 5.8/5.8 PATENTED TECHNOLOGY ZF Sachs CDC 2.2 10.34 3.3
To be ready for the future. Industrialized Tractive Valve -Calculated magnetic force versus position @ specified current. -Magnetic Force versus spring rate = slider displacement. -Slider displacement versus flow area -Flow Area vscurrent vsshock velocity. EQUALS Linearity and ultimate stability PATENTED TECHNOLOGY
Tractive DDA Specifications Dynamic Damping Adjustment valve valve is mounted on piston rod protected against outside influences controls directly rebound and compression oil flow in one valve Specifications Standard configuration valve normally closed (NC) Optional normally open, failsafe, tuneable soft setting Damping range from firm to soft: 0,5-2 A Power consumption 5 10 Watt Step response time 6 to 8 ms Range 0 10 kndamping force Package: 45 mm length effective, fits tubes >= 36 mm Ready for use in mono tube, emulsion and twin tube shock absorbers Part of the shock, therefore easy to install and package User friendly interface Already in use in motorcycle, snowmobile, ATV, Side by Side, and car shocks R(Ohm) L(mH-120Hz) L(mH-1Khz) Bilstein ( Nissan GTR& Porsche ) 2.5 12.8 5.45 Tractive SAF series 3.2 5.7 1.5 Tenneco Motorcycle serie 3.0/3.1 13.7/13.4 5.8/5.8 ZF Sachs CDC 2.2 10.34 3.3
Tractive DDA specifications Dynamic Damping Adjustment valve valve is mounted on piston rod protected against outside influences controls directly rebound and compression oil flow in one valve Specifications Standard configuration valve normally closed (NC) Optional normally open, failsafe, tuneable soft setting Damping range from firm to soft: 0,5-2 A Power consumption 5 10 Watt Step response time 6 to 8 ms Range 0 10 kndamping force Package: 45 mm length effective, fits tubes >= 36 mm Ready for use in mono tube, emulsion and twin tube shock absorbers Part of the shock, therefore easy to install and package User friendly interface Already in use in motorcycle, snowmobile, ATV, Side by Side, and car shocks R(Ohm) L(mH-120Hz) L(mH-1Khz) Bilstein ( Nissan GTR& Porsche ) 2.5 12.8 5.45 Tractive SAF series 3.2 5.7 1.5 Tenneco Motorcycle serie 3.0/3.1 13.7/13.4 5.8/5.8 ZF Sachs CDC 2.2 10.34 3.3
DDA valve adjustment range: three adjustment ranges available: 12x3, 8x3, 4x3 12x3 8x3 46150001S 12x3 46150001S2 8x3 46150001S1 4x3
To be ready for the future. multiple steps ahead Testing history DDA Valve: Functional: Linearity testing Magnetic hysteresis testing Mechanical hysteresis testing Aeration testing ( mono and twin ) Sine sweep testing Extreme temperature testing Step response testing EMC Testing Reproducibility testing for series Phase shift test activities Endurance testing: Various endurance test motorcycle. Various endurance tests snowmobile Laboratory endurance test ( desired specifications 1,6 miocycles still functional. Tractive test 18 miocycles still functional ) Contaminated oil tests Extreme side load tests Roll dynamometer test (road specs)
Global electrical step response 6 ms. Global electro hydraulic step response 8 12 ms Tractive DDA Specifications
Tractive DDA Specifications General specifications EMC ( EMV ) GS 95002. The Tractive DDA has been checked for EMC in order to get ABE for TÜV Approval according to RREG 97/24/8. Mechanical structural specifications like side load, pull and push forces have been calculated in ProMechanica and applied to the Tractive DDA Valve 25 kn pull & 2 kn side
General information Tractive DDA Valve Design for manufacturing All parts have been developed with focus on functionality and ability to be easily produced. Design for assembly All parts are easy to assemble and the valve is easy to calibrate on the end of line test. Already in use in aftermarket, prototype and OEM applications in motorcycle, snowmobile, ATV, Side by Side and car shocks Released for OEM by BMW, BRP Design freeze since 2012 PATENTED TECHNOLOGY
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