Patent Application
20050263127
The present invention relates to an automotive accessory drive pulley and, more particularly, to a double drive pulley assembly adapted to drive a plurality of automotive vehicle accessories and support loads associated therewith.
Automotive engine accessories such as generators, air conditioning compressors, and power steering pumps are typically driven by engine torque. The torque is transmitted through a serpentine belt wrapped around an engine crankshaft pulley and routed around a series of additional pulleys mounted on the front of the engine accessories. It is critical to position the accessories on the engine to ensure adequate belt wrap at the pulleys to provide maximum power transmission throughout all driving conditions. If the belt wrap is insufficient, the belt may slip under certain conditions. Belt slippage results in reduced accessory performance, reduced belt durability, and increased noise. Additionally, it is critical to ensure that the belt or belts are adequately taught to provide maximum power transmission and to minimize belt slippage. However, high belt tension results in high radial loads being transferred to the crankshaft and other pulleys. These radial loads are then transferred to the engine accessory drive shafts, which can ultimately reduce the useful life of the accessories.
Further design challenges relate to the desire of Original Equipment Manufacturers to increase the number of engine accessories, thereby increasing the complexity of these belt and pulley systems, while reducing the envelope available for the engine and the engine accessories. One attempt to overcome these challenges includes driving a plurality of belts directly from the crankshaft, thereby providing direct power to a plurality of accessories. Unfortunately, vehicle steering, suspension, or any other automotive system or systems may occupy the packaging space and preclude the use of a plurality of drive belts directly driven by the crankshaft.
The present invention provides a pulley assembly adapted to transmit torque from a drive pulley to first and second driven accessories. The pulley assembly generally includes a housing and an auxiliary drive component. The auxiliary drive component is rotatably supported by the housing and adapted to be coupled to the first driven accessory. The auxiliary drive component includes first and second annular drive surfaces. The first drive surface is adapted to be drivingly coupled to the drive pulley and the second drive surface is adapted to be drivingly coupled to the second driven accessory.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the scope of the invention, its application, or its uses.
Referring to
During operation, the serpentine belt 34 transfers torque produced by an engine 10, via the crankshaft pulley 14, to the air conditioner compressor 16 and power steering pump 24. In addition, the auxiliary belt 36 transfers drive torque from the crankshaft pulley 14 to the supercharger 30, via the pump pulley 26. It should be appreciated that while the double sheave pulley assembly 100 is illustrated as being employed on the power steering pump 24, alternate locations are within the scope of the present invention. For example, the double pulley assembly may be coupled to a water pump, a generator, a hydraulic pump, an air conditioning compressor, a supercharger, or another accessory not listed.
The housing 102 includes a body portion 106 and a flange portion 108. The body portion 106 includes a generally cylindrical interior surface 110 and a generally conical exterior surface 113. The flange portion 108 includes a plurality of recesses 107 that receive a plurality of fasteners 109 to mount the double sheave pulley assembly 100 to the engine 10.
The auxiliary drive component 104 includes a shaft 112 and a rotary member 114. The shaft 112 includes a first end 112a having a threaded internal bore 116 and a second end 112b having an external flange 118 and a plurality of internal teeth 120. The rotary member 114 includes a pulley portion 122 and a base portion 124. The pulley portion 122 is generally cylindrical in shape and includes a first plurality of annular grooves 126 defining the second pulley portion 100b and a second plurality of annular grooves 128 defining the first pulley portion 100a. The base portion 124 is a generally circular plate having an aperture 130. The aperture 130 receives the first end 112a of the shaft 112 to support the rotary member 114 thereon.
The shaft 112 supports the auxiliary drive component 104 for rotation relative to the housing 102. A first bearing 132 is positioned at the first end 112a of the shaft 112. A second bearing 134 is positioned at the second end 112b of the shaft 112. The first bearing 132 includes an inner race 136 and an outer race 140. The second bearing 134 includes an inner race 138 and an outer race 142. Outer race 140 is press-fit within a counter-bore 143 of the housing 102. Outer race 142 is press-fit within a counter-bore 145 of the housing 102. The inner races 136, 138 are slip-fit on the shaft 112. A shaft sleeve 144 is positioned on the shaft 112 between the first bearing 132 and the second bearing 134 to space apart the first 132 and second 134 bearings a predetermined distance.
A threaded fastener 146 threadably engages the threaded internal bore 116 of the shaft 112 to maintain axial engagement of the components of the assembly 100. A head 148 on the threaded fastener 146 engages a washer 150, which in turn engages the base portion 124 of the rotary member 114 on the auxiliary drive component 104. The base portion 124 engages the inner race 136 of the first bearing 132. The inner race 136 of the first bearing 132 engages the shaft sleeve 144. The shaft sleeve 144 engages the inner race 138 of the second bearing 134. Finally, the inner race 138 of the second bearing 134 engages the external flange 118 formed on the second end 112b of the shaft 112. Hence, the threaded fastener 146 clamps the rotary member 114, the first bearing 132, the shaft sleeve 144, and the second bearing 134 between the external flange 118 and the washer 150 to provide proper alignment and support for rotary member 114.
During operation, the plurality of internal teeth 120 on the second end 112b of the shaft 112 are splined to a plurality of external teeth 152 formed on the input shaft 105. A drive belt 34 (shown in
The housing 202 includes a body portion 206 and a flange portion 208. The body portion 206 has a substantially cylindrical interior surface 210 and a substantially conical exterior surface 212. The flange portion 208 includes a plurality of recesses 214 that receive a plurality of fasteners 216 for being mounted to the engine 10.
The auxiliary drive component 204 is a one piece member including a shaft portion 218, a pulley portion 220, and a base portion 222. The shaft portion 218 is rotatably supported within the housing 202, thereby rotatably supporting the pulley portion 220 outside the housing 202. The shaft portion 218 includes an outer end 218a and an inner end 218b. The inner end 218b includes a plurality of internal teeth 224 and an annular channel 226. The pulley portion 220 includes a first plurality of annular grooves 228 and a second plurality of annular grooves 230. The base portion 222 is a substantially circular plate that provides the radial transition between the shaft portion 218 and the pulley portion 220.
A first bearing 231 is positioned at the outer end 218a of the shaft portion 218. A second bearing 232 is positioned at the inner end 218b of the shaft portion 218. The first bearing 231 includes an inner race 234 and an outer race 238. The second bearing 232 includes an inner race 236 and an outer race 240. Outer race 238 is press-fit within counter-bore 242 of the housing 202. Outer race 240 is press-fit within counter-bore 244 of the housing 202. The inner races 234, 236 are slip-fit on the shaft portion 218. A shaft sleeve 246 is positioned between the bearings 231, 232. A snap ring 248 engages the annular channel 226 formed in the inner end 218b of the shaft portion 218.
During assembly, the bearings 231, 232, shaft sleeve 246, and housing 202 are assembled before applying the snap ring 248. This aforementioned assembly is pre-loaded in the axial direction and then the snap ring 248 is applied to the annular channel 226. The snap ring 248, thus, provides a clamping force to the components of the assembly 200. The snap ring 248 engages the inner race 236 of the second bearing 232. The inner race 236 of the second bearing 232 engages the shaft sleeve 246. The shaft sleeve 246 engages the inner race 234 of the first bearing 231. The inner race 234 of the first bearing 231 engages a shoulder 250 formed on an inside surface of the base portion 222 of the auxiliary drive component 204.
Operation of this alternative embodiment of the double sheave pulley assembly 200 is similar to that of the first embodiment described above. The plurality of internal teeth 224 on the inner end 218b of the shaft portion 218 are engagingly splined to a plurality of external teeth 252 on the input shaft 205 of the vehicle accessory. A drive belt 34 (shown in
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
