The present invention relates generally to a hybrid vehicle, and more specifically to an arrangement to reduce the transmission of noise within a vehicle driveline.
Vehicle drivelines transmit power from a vehicle engine through a transmission and then to the front wheels, rear wheels or all four wheels as desired. Commonly, a driveshaft assembly, or propshaft, is used to transmit torque from an output shaft of the transmission to the rear of the vehicle. The driveshaft assembly would then be connected to an axle, to propagate the torque to the vehicle wheels.
Driveshaft assemblies are known to transmit noise and vibration from operation of the engine, transmission, and the driveshaft assembly itself to the axle and from there into the passenger compartment of the vehicle. Dampers are commonly used within the driveline to reduce the vibration and noise from transmitting farther within the vehicle.
However, hybrid vehicles additionally produce electromagnetic frequencies (EMF) due to the electrical components in the hybrid system. The EMF can cause disruption of the various non-hybrid electrical systems in a vehicle. One impact of the EMF is degradation of the AM radio reception. However, traditional dampers do not prevent transmission of the electrical frequencies. In fact, driveshaft assemblies within the driveline system can amplify the EMF that are transferred to the driveline by the hybrid system.
A vehicle having a driveline and a hybrid transmission where the transmission is electrically isolated from the remainder of the vehicle driveline is desired.
A vehicle driveline with a transmission having at least one motor/generator and an output shaft is provided. A driveshaft assembly is rotatably connected to the output shaft. The driveshaft assembly includes an isolator located between the transmission and at least a portion of the driveshaft assembly to electrically isolate the driveshaft assembly from the transmission.
The driveshaft assembly includes a transmission universal joint for mounting to a transmission, an axle universal joint for mounting to an axle and a shaft extending between the transmission universal joint and the axle universal joint. The isolator is located on the transmission universal joint.
A method for reducing noise and vibration in a vehicle driveline includes positioning the isolator on the driveshaft assembly to electrically isolate at least a portion of the driveshaft assembly from the transmission
The above features and advantages, and other features and advantages of the present invention will be readily apparent from the following detailed description of the preferred embodiments and best modes for carrying out the present invention when taken in connection with the accompanying drawings.
Referring to the Figures, wherein like reference numbers refer to the same or similar components throughout the several views,
The vehicle driveline 12 includes a hybrid transmission 14. The hybrid transmission 14 has at least one motor/generator 16 located therein to assist the vehicle engine 20 and store power as is known for hybrid transmissions. The transmission 14 includes a transmission output shaft 18 (shown in
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The yoke arm 38 may have a bore isolator 42. The bore isolator 42 is preferably a ceramic or nylon coating applied to the yoke arm 38 within the bore 40 to electrically isolate the yoke arm 38 from the spider 44 for the universal joint 23.
A bearing isolator 48 may also be located on an outer surface 50 of the bearing cup 46 to electrically isolate the yoke arm 38 from the spider 44. The bearing isolator 48 is preferably a ceramic or nylon coating applied to the outer surface of the bearing cup 46 to electrically isolate the yoke arm 38 from the spider 44 for the universal joint 23.
By providing at least one of the yoke isolator 34, the bore isolator 42 and the bearing isolator 48, the transmission 14 is electrically isolated from the driveshaft assembly 22 and the remaining portion of the driveline 12. In particular, the shaft 25 of the driveshaft assembly 22 is electrically isolated from the transmission 14 to prevent amplification of any electrical vibrations associated with the various electric components, such as the motor/generator 16, within the transmission 14. The vehicle 10 may utilize one or any combination of the yoke isolator 34, bore isolator 42 and the bearing isolator 48 as is necessary to electrically isolate the transmission 14 from the remaining portion of the driveshaft assembly 22 and the driveline 12.
The above example describes a rear wheel-drive hybrid transmission 14 configuration. Other hybrid transmission configurations, such as front wheel-drive or all wheel-drive may benefit as well.
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.