Abstract:
A sensor for sensing torque applied to a shaft such as the steering wheel shaft of a vehicle has a magnetostrictive sleeve and a sensing element responsive to torsional strain in the magnetostrictive sleeve. Each end of the magnetostrictive sleeve is torsionally engaged to a shear leveling member. Each shear leveling member has a region of varying torsional stiffness and a flared end. Each shear leveling member is bonded to the shaft by adhesive at its region of varying torsional stiffness and at its flared end. The regions of varying torsional stiffness and flared ends operate to level the shear stress in the adhesive resulting in uniform shear stress without peaks throughout the adhesive bond. With uniform adhesive shear stress, the maximum torque the adhesive can transmit is limited only by the yield torque of the shaft and the area of adhesive bond. The area of adhesive bond can be increased without limit by increasing the length of the shear leveling member thereby making the yield torque of the shaft the only limit to the torque transmitted. In one embodiment a stack of washers provides radial forces to stabilize the surface of the magnetostrictive sleeve without applying torque to the sleeve. The response of the sensor is made independent of angular position by providing a circularly symmetric sensing element located on the axis of rotation of the sleeve.
Abstract:
A canister contains two cartridges of activated carbon for storing fuel in gasoline powered motor vehicles. A first cartridge operates to adsorb gasoline vapor produced in the fuel tank while the vehicle is not operating. The second cartridge operates to adsorb gasoline vapor from the fuel tank. Vacuum from the intake manifold or a vacuum pump draws fuel saturated air from the fuel tank and through the second cartridge thereby charging it with adsorbed fuel. Charging is terminated when fuel passes through the second cartridge without being adsorbed. Much or most of the fuel adsorbed is the lightest and most volatile fraction of the gasoline which is usually butane. Fuel vapor from both cartridges is combined with air to fuel the vehicle on initial startup thereby providing vaporized fuel to the vehicle engine and purging both cartridges of fuel. An air-fuel ratio sensor and a fuel vapor sensor are jointly achieved by comparing the transit time of sound in two chambers, one containing air and the other containing a mixture of air and fuel. The air-fuel ratio sensor measures the ratio of air to fuel provided to the engine during initial startup. The fuel vapor sensor senses the onset of vapor passage during charging of the second cartridge. The ratio of air to fuel provided to the engine during initial startup may also be ascertained by providing a mass flow sensor in the outlet of the fuel vapor source. During initial startup a valve controls flow of vapor from the canister to maintain a desired air-fuel ratio.
Abstract:
A crash sensing switch for automotive vehicles has a cylindrical piston that moves sealingly in a tube during a crash to bridge a pair of contacts. Viscous flow of air through ducts creates pressures that resist movement of the piston. A venting valve may be incorporated in the piston to increase contact dwell. Impedance of the ducts may be adjusted during manufacture by blocking one or more of the ducts. The clearance between the piston and the tube limits air flow between the piston and the walls of the tube and provides aerodynamic lubrication between the piston and the tube during cross axis vibrations. A piston ring may assist in preventing air flow between the piston and the walls of the tube. There may be compensation for changes of air viscosity with temperature. One way to compensate is to make the contacts of thermostat metal which bends with temperature to change the distance the piston must move to bridge the contacts. Another way is to provide a valve incorporating thermostat metal which opens or closes certain ducts to compensate for changes of air viscosity with temperature. Compensation for variation of air viscosity with temperature may be provided at higher temperatures but not at lower temperatures. An injection molded cap includes connector pins to form an integral connector and hermetically seal the interior from the environment. Contact height setters may be incorporated into the cap to assure the desired piston movement for switch closure. Calibration may be done at manufacture by adjusting the piston movement required for switch closure. The combination of these elements provides a crash sensing switch having superior performance and costing much less than known crash sensing switches.
Abstract:
A crash sensor for automobiles of the type including a sensing mass movable in a closed chamber against pressure resulting from viscous flow has a disk shaped sensing mass suspended by one or two webs like those used to suspend the moving elements of audio speakers. The web suspending the sensing mass allows the sensing mass free axial motion while resisting radial motion. Movement of the sensing mass is resisted by air pressure resulting from viscous flow of air through conduits. Compensation for variation of air viscosity with temperature is achieved by varying the travel of the sensing mass. The sensor design enables accurate automatic calibration. The unit is compact and is made from a small number of inexpensive parts. The combination of these elements provides a crash sensor that is insensitive to cross axis vibrations and costs much less than current production sensors.
Abstract:
A crash sensor for automobiles of the type including a ball moving against viscous damping in a closed cylinder for releasing a firing pin for initiating a pyrotechnic sequence has an improved release mechanism. When the ball moves a predetermined distance from its normal or resting position during an automobile crash a release mechanism releases a belleville spring maintained under stress. The belleville spring thereupon initiates movement of a firing pin towards a stab primer. The release mechanism is a single piece of spring material having multiple levers extending radially inward from a torsionally elastic ring, each lever having a detent and a pivot. The firing pin is mounted on and driven by a snap disk which is normally in its position of higher energy equilibrium and is released to go to its position of lower energy equilibrium by pressure applied by the belleville spring.
Abstract:
A power steering system for vehicles is disclosed using an electric servomotor. The servomotor is energized for power assist in executing turns and for reducing the drag of the servomotor during the return of the dirigible wheels to the straight ahead position. A torque transducer operatively coupled with the steering wheel shaft and the steering gear generates a torque signal corresponding to the torque applied by the driver to the steering wheel. A lost motion coupling is provided between the servomotor and the steering gear and a lost motion transducer is operatively coupled therewith to develop a signal corresponding to lost motion. The torque signal and the lost motion signal are combined differentially and the resultant signal is applied to the servo amplifier for energization of the servomotor. When the driver turns the steering wheel, the torque signal predominates and the servomotor is energized to provide power assist. When the driver releases the steering wheel, the torque signal drops to zero and the lost motion signal controls the energization of the servomotor to overcome its resistance to the return of the dirigible wheels to the straight ahead position. A second configuration provides a compact unit of cylindrical symmetry.
Abstract:
A mechanical coupling for a power steering system and the like having a driven member reversibly rotated by a servo-motor in response to either clockwise or counterclockwise rotation of a control member, with the coupling normally connecting the motor to the driven member through a drive transmitting member. In the event of any failure of the motor to rotate the driven member synchronously with the control member, as for example, due to an electrical power failure, rotation of the control member relative to the driven member causes the coupling to disconnect the drive transmitting member and thereby disconnect the motor from the driven member to prevent transmission of torque in the direction opposite to the torque applied by the control member and simultaneously mechanically couple the control member to the driven member for direct drive. During that time, the coupling continues to connect the drive transmitting member to the driven member for transmission of torque in the direction of the torque applied by the control member. An improved drive transmitting coupling is disclosed which comprises a lost motion connection between the control member and the driven member with first and second one-way clutches for coupling the driven member with the drive transmitting member. Each of the clutches includes a set of pivoted pawls mounted on the driven member for driving engagement with the drive transmitting member for driving the driven member in one direction and a set of actuating members mounted on the driven member for disengaging the respective pawls in response to rotation in the opposite direction of the control member relative to the driven member.
Abstract:
A system for detecting fluid on a substrate is provided. The system includes, but is not limited to, a sensor board, a first capacitive sensor, and a platform upon which the substrate is to be placed. The first capacitive sensor is mounted on the sensor board. The first capacitive sensor has a transmit sensor pad for transmitting a signal, a receive sensor pad for receiving the signal, and an analog-to-digital convertor connected with the receive sensor pad for analyzing the received signal. The platform is a first distance from the transmit and receive sensor pads.
Abstract:
Systems and methods for controlling a heater to drive a load temperature to approximate a setpoint. At the beginning of each ½ AC cycle, a sigma delta modulation algorithm is computed to determine whether the AC cycle should be turned on or off. The running estimate of the past actual duty cycle is compared to the desired output duty cycle, and the difference between the two is used to adjust the next ½ cycle's output. This results in a pseudo-random pulse sequence output which does not contain significant periodic components that could cause undesirable small periodic thermal ‘ripples’ on the element being heated.
Abstract:
Systems and methods for controlling a heater to drive a load temperature to approximate a setpoint. At the beginning of each ½ AC cycle, a sigma delta modulation algorithm is computed to determine whether the AC cycle should be turned on or off. The running estimate of the past actual duty cycle is compared to the desired output duty cycle, and the difference between the two is used to adjust the next ½ cycle's output. This results in a pseudo-random pulse sequence output which does not contain significant periodic components that could cause undesirable small periodic thermal ‘ripples’ on the element being heated.