Patent Application
20180320763
The disclosed inventive concept relates generally to pulley systems for vehicle engines. More particularly, the disclosed inventive concept relates to an adjustable bracket system fitted to a belt-driven component for use with a low modulus or stretch fit drive belt. The adjustable bracket system utilizes a rotatable insert having an offset fastener and an adjustable locking bracket arrangement.
The modern internal combustion engine usually incorporates a pulley drive system for powering accessories driven by the engine crankshaft. The accessories typically include an air conditioning compressor, a power steering pump, a water pump, and an alternator. Such accessories make up the front end accessory drive system (or “FEAD system”). Each of the accessories requires a driven pulley.
A front end accessory drive belt is trained around pulleys to supply power from the crankshaft of the engine to the accessories. The drive belt makes frictional contact with the face of the pulleys. Drive belts developed from the flat leather belt to V-belts and more recently to multi-V or serpentine belts. Most drive belts used today are formed from a flexible reinforced polymeric material.
However, to reduce both production cost and packaging, automobile manufacturers have more recently adopted low modulus or stretch fit belts that, unlike the widely-used multi-V or serpentine belts, have an effective degree of elasticity because of reinforcing cords made from polyamide material. The reinforcing cords of the most prevalent serpentine belt used today incorporate relatively inelastic aramid or polyester cords. The modern stretch fit belt is thus finding increased usage on FEAD systems to transmit torque from the engine crankshaft to one or more engine mounted accessories as is the case with traditional belts.
Stretch fit belt systems have a cost and package advantage over standard FEAD system belts that require and automatic spring loaded belt tensioner. No tensioning is required for stretch fit belts as these belts are self-tensioning. While having the appearance of conventional serpentine belts, stretch fit belts generally cannot be used on vehicles designed for use with standard drive belts. However, in some cases, it is possible to use a stretch fit belt on vehicles designed for use with conventional serpentine belts. This requires removal of the automatic tensioner and potentially some re-routing of the belt path.
The disadvantage of stretch fit belts is in the area of installation and service. The length of the stretch fit belt is actually less than the actual working length. However, when installed, the stretch fit belt is automatically tensioned. Installation is difficult because of assembly plant cycle time and the fact that the stretch fit belt has to be stretched over the pulley flanges for installation. This requires specialized tools that take up manufacturing line space and can also slow down cycle time. Belts are often cut off in service, creating additional cost for the customer, as a new belt is required even if the stretch fit belt is not the reason for the vehicle service.
As in so many areas of vehicle technology there is always room for improvements related to the design of a system for use with the modern stretch fit belt. Particularly, it would be advantageous to provide a modified FEAD system that can be readily adapted for use with a stretch fit belt without the need for specialized tools.
The disclosed inventive concept overcomes the problems of known FEAD systems for engines that utilize low modulus or stretch fit drive belts by providing an adjustable and lockable bracket assembly that allows the stretch drive belt to be installed loosely on the pulleys of the accessory drive system and then subsequently tightened by adjustment and tightening of the assembly. The bracket assembly includes a fixed bracket that is attached to the engine, a pivoting and lockable bracket attached to the fixed bracket and to an adjustable driven unit, an adjustable arm for moving the adjustable driven unit between a “belt install” position that allows for attachment of the stretch fit belt and a “final” position for stretching the attached belt, and a rotatable insert having an offset threaded hole into which a fastener is threadably inserted attached to the adjustable arm for moving the driven unit between the “belt install” and “final” positions.
When the rotatable insert is rotated to move the driven unit to the “belt install” position via the adjustable arm, the stretch fit belt may be fitted over the pulleys of the FEAD system including over the pulley of the driven unit. Once in position, the rotatable insert is rotated to move the driven unit to the “final” position again via the adjustable arm, thereby taking up the slack in the belt and putting it in tension for proper operation. The rotatable insert may be rotated using a conventional tool, thus avoiding the need for specialized tooling.
Once the rotatable insert is rotated so that the driven unit is in its “final” position, the pivoting and lockable bracket attached to the fixed bracket and the fastener attached to the rotatable insert are mechanically locked against movement. In the event that the engine requires service that necessitates the removal of the stretch drive belt, steps for removal of the belt are opposite those required to install the belt. Specifically, the fasteners of the pivoting bracket are loosened, the rotatable insert is rotated to release the tension on the belt, and the belt is removed without damage and re-used if necessary.
The above advantages and other advantages and features will be readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings.
For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention wherein:
In the following figures, the same reference numerals will be used to refer to the same components. In the following description, various operating parameters and components are described for different constructed embodiments. These specific parameters and components are included as examples and are not meant to be limiting.
In general, the disclosed inventive concept provides a practical and cost-effective approach to a pulley system that allows for simplified installation of a stretch fit belt without the need for specialized tooling. The system of the disclosed inventive concept allows the installer to (1) loosen fasteners on an adjustable bracket associated with the driven accessory using a conventional tool, (2) place the stretch fit belt on the pulleys of the FEAD system in its initial or “belt install” position, (3) rotate the rotatable element of an adjustment assembly using a conventional tool until the driven accessory is moved to its “final” position in which the belt is rendered taught, and (4) tighten the fasteners on the adjustable bracket and on the rotatable insert.
The arrangement of the disclosed inventive concept is illustrated in the accompanying figures and is illustrated in various stages in the figures. Particularly, in
With reference to
The driven accessory 12 includes an accessory pulley 20. The accessory pulley 20 provides an attachment surface for a low modulus or stretch fit drive belt 22. As illustrated in
One end of a first accessory arm 32 is fixedly attached to the driven accessory 12. The other end of the first accessory arm 32 is attached to a second end 34 of the movable cantilevered bracket 24. The first accessory arm 32 is releasably attached to the movable cantilevered bracket 24 by an adjustable fastener 36.
One end of a second accessory arm 38 is fixedly attached to the accessory 12 and the other end of the second accessory arm 38 and movably attached at one end to a rotatable adjustment assembly 40 (partially illustrated in broken lines in
The rotatable adjustment assembly 40 is illustrated in isolation in
As illustrated in
Once the stretch fit drive belt 22 has been loosely fitted over the pulley 20 of the driven unit 12, adjustment of the driven unit 12 can be undertaken.
Continued rotation of the rotatable cylinder body 46 results in movement of the stretch fit belt bracket assembly 10 to its “final” position in which the stretch fit drive belt 22 has been fully elongated to its operating condition. This aspect of the disclosed inventive concept is illustrated in
As shown particularly in
Once in the position illustrated in
The stretch fit belt bracket assembly 10 of the disclosed inventive concept offers several advantages over known FEAD systems that utilize a stretch fit belt. The stretch fit belt bracket assembly 10 avoids the need for special tooling for installation or removal and further avoids the need for a special service procedure. Not only does this advantage greatly aid the repair technician, it also helps on the production line where no specific installation equipment is required. In addition, because the adjustment elements that allow for easy and reliable belt installation and removal are integral with the stretch fit belt bracket assembly 10, the no tool other than, for example, the most basic socket wrench needs to be used when service is required. It is to be understood that while the stretch fit belt bracket assembly 10 is characterized herein as finding use with an automotive vehicle, the same assembly may be used in any situation where a low modulus or stretch fit belt is used including, without limitation, agricultural, marine and industrial settings.
One skilled in the art will readily recognize from the above discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.
