Intake manifold shaft and blade attachment

An arrangement for attaching a blade to a shaft for use in intake manifolds, uses fasteners that create a load on the blade. Fasteners are inserted through fastener holes in the blade and through shaft holes in the shaft. Once inserted outward pressure by the fastener on the shaft and the blade places the assembly under a constant load. The load prevents the shaft and the blade from vibrating against each other during engine operation. The same attachment method can also be used to retain and bias a shaft locater to the shaft.

BACKGROUND OF THE INVENTION

This invention relates generally to an arrangement for attaching a blade to a shaft for use in intake manifold assembly, which reduces noise and vibrations between the shaft and blade.

Intake manifolds control the amount of air entering internal combustion engines. Air enters the intake manifold and flows through to the engine. Intake manifolds use shaft and blade assemblies to control the intake of air into the manifold assembly.

The shafts have commonly been manufactured from plastic and coated with rubber to lower vibration and noise. However, plastic shafts have low durability and strength. The blades are also manufactured from plastic. Prior art blades are molded from plastic and have circular portions designed so the blade can slide onto the shaft.

During manufacture imperfections occur in the shaft, other assembly components, and the manifold housing due to manufacturing tolerances. Manufacturing variations in the shaft and the blades create clearance problems when the blades and the shaft are assembled. The imperfections may be minimal while at rest. However, during operation an imperfect fit between the blades and shaft may cause the blades and shaft to vibrate, creating chatter noise.

An arrangement for attaching intake manifold shafts and blades to reduce vibration noise during engine operation is needed.

SUMMARY OF THE INVENTION

The invention is an arrangement for attaching a blade to a shaft for use in intake manifolds. An intake manifold shaft sub-assembly has a shaft with at least one blade attached to the shaft by using fasteners that create a load on the blade. The load prevents the shaft and the blade from vibrating against each other during engine operation.

The fasteners are preferably spring pins. However, any fastener may be used which will apply a load to the shaft and blade once assembled. The blade has a shaft interface formed to at least partially surround the shaft. However, due to manufacturing variances the shape of the shaft interface may not exactly match the contour of the shaft.

The fasteners are inserted through fastener holes in the blade and through the shaft holes in the shaft. Once inserted the fasteners expands slightly to create a press fit. The outward pressure by the fastener on the shaft and the blade places the assembly under a constant load. The load prevents vibration between the shaft and blade, even when clearances exist.

The same attachment method can also be used to retain and bias a shaft locater to the shaft. Once the shaft assembly is assembled within the intake manifold housing, a housing wall prevents the fasteners from leaving the fastener holes and falling in the engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1shows an intake manifold assembly10. The intake manifold assembly10includes a housing12, a shaft assembly14, an intake insert16, and a flange seal18. The shaft assembly14is assembled into opening20within the housing12. The intake insert16is placed within the opening20to retain and support the shaft assembly14. The flange seal18is assembled last. The flange seal18seals around the opening20once the intake manifold assembly10is mounted to the engine. Bolts or other fasteners may be used to retain the shaft assembly14within the housing12until the intake manifold assembly10can be mounted to the engine. Once mounted to the engine the shaft assembly14is held in place by the engine. An actuator22is mounted on the housing12. Following assembly, actuator22is connected to the shaft assembly14. During operation of the engine the actuator22controls airflow through the main passage of the intake manifold assembly10by rotating the shaft assembly14, as known.

The shaft assembly14has a shaft24with at least one blade26attached to the shaft24. The shaft24and blade26may be manufactured from metal, preferably aluminum. As shown inFIG. 3, the blade26is attached using fasteners28. Fastener102is shown fully inserted within the shaft24and the blade26. Fastener104is shown partially inserted within the shaft24and the blade26. The blade106is shown positioned on the shaft24prior to insertion of the fasteners28. In the embodiment shown, the fasteners are spring pins. A spring pin fastener28has a c-shaped cross-section, shown inFIG. 2A. As represented by arrows P, pressure is applied to an outer surface29of the fastener28during assembly into the blade26and shaft24. Pressure may be applied with pliers, by hand, or other appropriate methods. Once the fastener28is inserted, pressure to the outer surface29is removed and the fastener28expands in circumference,FIG. 2B. The expanded circumference of the fastener28places a small load on the shaft24and the blade26. The load prevents the shaft24and the blade26from vibrating against each other during engine operation. Although spring pins are shown, any fastener28may be used which will apply a load to the shaft24and blade26once assembled.

Referring toFIG. 3, the blade26has a shaft interface30formed to at least partially surround the shaft24. The shape of the shaft interface30corresponds to the shape of the shaft24. Due to manufacturing variances the shaft interface30often does not exactly match the contour of the shaft24.

FIG. 4shows a cross-section of the shaft24and the blade26assembled in the housing12. Fastener holes32and32′ are drilled into the blade26during manufacture. The fastener holes32and32′ in the blade26correspond with shaft holes34once assembled. Fastener28is inserted through the fastener holes32and32′ in the blade26and through the shaft holes34in the shaft24. Once inserted pressure used to assemble the fastener28is removed. The fastener28expands slightly to create a press fit. The outward pressure by the fastener28on the shaft24and the blade26places the shaft assembly14under a load. The load prevents vibration between the shaft24and blade26. The pressure applied by the fastener28is enough to create a constant load however, is small enough to not stress the shaft24and blade26.

The fastener holes32and32′ in the blade26are formed to prevent the fastener28from being able to enter the cylinder head once the shaft assembly14has been installed within the intake manifold housing12. The fastener hole32extends completely through the shaft interface30while the fastener hole32′ does not extend all the way through the shaft interface30. That is, portion35of the shaft interface30prevents the fasteners28from passing through the fastener hole32′. Once the shaft assembly14is assembled within the housing12the walls33of the housing12prevent the fastener28from exiting back through the fastener holes32and32′. Thus, the fasteners28cannot become loose within the engine or intake manifold assembly10.

In addition, although the above embodiment showed fasteners28which create a bias between a blade26and a shaft24the fasteners28can also be used to retain and bias a shaft locater36, as shown inFIG. 5. Each shaft locator36is assembled to the shaft24by fasteners28, which operate to attach the shaft locator36to the shaft24in a manner similar to the attachment of the blade26to the shaft24as described above. The shaft locator36assists in controlling airflow through the intake manifold assembly10. The shaft locator36provides feedback on the rotational position of the shaft24to control the position of the blade26within the intake manifold assembly10.