Combination electric generator with electric clutch

This application claims the benefit of Provisional Application No. 62/056,134, filed Sep. 26, 2014, and Provisional Application No. 62/058,577, filed Oct. 1, 2014. These prior applications are incorporated herein by reference in their entirety.

This invention relates to a combination of an electric generator and an electric clutch for use in a drive system that may be used in vehicles such as lawn and garden tractors, stand-on mowers, walk-behind snow throwers and mowers, and the like.

The invention comprises a combination of an electric generator and an electric clutch. In one embodiment disclosed herein, the electric clutch is integrated with the bottom housing member of the generator housing, such that the generator and clutch are located adjacent to one another in a low-profile configuration. A field coil of the electric clutch is mounted on an external surface of the generator housing, reducing the height of the overall unit. In a further embodiment, the generator and clutch are in a side-by-side relationship and a field coil of the electric clutch is mounted to an external surface of an extension of the generator housing, which also serves as a portion of a housing for a belt drive system to connect the generator and clutch to a common input from the prime mover, thus also providing a low-profile configuration. The combination generator and clutch taught herein may be used in connection with a vehicle, wherein both the electric clutch and other apparatuses on the vehicle are powered by the generator.

A better understanding of the invention will be obtained from the following detailed descriptions and accompanying drawings, which set forth illustrative embodiments that are indicative of the various ways in which the principals of the invention may be employed.

FIG. 1 is a partially schematic drawing of an exemplary vehicle incorporating a combination electric generator and clutch assembly.

FIG. 2 is a side elevational view of a combination electric generator and clutch assembly.

FIG. 3 is a cross sectional view of the combination electric generator and clutch assembly of FIG. 2 along line 3 - 3 in FIG. 2 .

FIG. 4 is a partially schematic drawing of an exemplary vehicle incorporating a second embodiment of a combination electric generator and clutch assembly.

FIG. 5 is a cross sectional view of the combination electric generator and clutch assembly of FIG. 4 along the line 5 - 5 in FIG. 4 .

FIG. 6 is a partially schematic drawing of another exemplary vehicle incorporating an alternative embodiment of a combination electric generator and clutch assembly in accordance with the teachings herein.

The description that follows describes, illustrates and exemplifies one or more embodiments of the invention in accordance with its principles. This description is not provided to limit the invention to the embodiment(s) described herein, but rather to explain and teach the principles of the invention in order to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiment(s) described herein, but also any other embodiment that may come to mind in accordance with these principles. The scope of the invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents.

It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers or serial numbers in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. As stated above, this specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood by one of ordinary skill in the art.

FIG. 1 illustrates a riding vehicle 100 including a pair of electric wheel motors 139 L, 139 R to power a pair of driven wheels 116 L, 116 R. A set of caster wheels 112 is disposed at the front of frame 110 , which also supports a mowing deck 117 having a plurality of mowing blades 119 . A prime mover 120 , which may be an internal combustion engine, is also disposed on frame 110 near the rear thereof. It will be understood that operator input controls and an operating seat or platform for the operator of the vehicles disclosed herein would be provided as well. In this embodiment, vehicle 100 includes a belt and pulley system 123 that connects the output shaft 120 a of prime mover 120 with mowing blades 119 via generator clutch brake assembly 160 ; the connecting belt and pulley system 123 can be of a standard form and is not critical to this invention.

Vehicle 100 also includes a controller 132 supported by frame 110 and operatively connected to battery 124 and to wheel motors 139 L, 139 R. As will be described below, controller 132 also supplies power to electric clutch-brake assembly 162 via conductor 126 .

Generator clutch brake assembly 160 is shown in FIGS. 2 and 3 , where it can be seen to include a generator 161 having upper housing member 167 and lower housing member 168 forming a single generator housing. A rotatable member, namely input tube 163 , extends through generator 161 and is supported in part by upper bearing 164 in upper housing member 167 and by intermediate bearing 165 in lower housing member 168 . A lower bearing 166 is located in output hub 153 to support rotation of output hub 153 and pulley 154 when the clutch is engaged. It is preferred that each of the bearings 164 , 165 , 166 be sealed bearings to eliminate the need for additional seals, thereby further reducing the height of the overall unit.

Input tube 163 also comprises clutch rotor 163 a formed therewith, and it will be understood that the output shaft 120 a of prime mover 120 extends into the input tube 163 and is connected thereto by known means, including fastener 170 so that input tube 163 rotates with the prime mover output shaft 120 a . It will be understood that other rotatable input means can be used to connect with an output shaft of the prime mover and transfer the rotational movement as outlined herein, in place of the disclosed input tubes.

Generator 161 comprises a stator 146 fixed within housing members 167 and 168 and incorporating coil windings formed in stator 146 in a known manner. Magnets 144 and 145 are fixed on upper rotor 142 and lower rotor 143 , respectively, to rotate adjacent stator 146 and generate an electric current in a known manner. The output of generator 161 is provided to battery 124 by means of conductor 125 , as shown in FIGS. 1 and 2 . At least one anti-rotation device 169 is provided to prevent rotation of generator clutch brake assembly 160 .

To simplify construction and operation, an electric clutch-brake assembly 162 is used in combination with generator 161 to selectively connect output hub 153 and pulley 154 to input tube 163 . A field coil 150 is fixed to an external surface of lower housing member 168 of generator 161 by known methods, such as adhesives. This arrangement helps to reduce the overall height of the assembly 160 , conserving ground clearance in utility vehicles such as riding vehicle 100 . Field coil 150 is powered by conductor 126 connected to controller 132 . Clutch-brake disk 151 is fixed to output hub 153 by means of a plurality of leaf springs 152 and engages the inner surface of brake shroud 155 , as shown in FIG. 3 , to provide a braking force to output hub 153 . Clutch-brake disk 151 is biased to this braking position by means of the plurality of leaf springs 152 . When field coil 150 is energized, clutch-brake disk 151 is magnetically pulled to engage clutch rotor 163 a , thereby engaging the output hub 153 and pulley 154 with input tube 163 to provide rotational output thereto. It will be understood that frictional material will be used on the various components as needed.

As shown in FIGS. 2 and 3 , brake shroud 155 is secured to the lower housing member 168 by a plurality of adjustment mechanisms 172 . Gap adjustment mechanisms 172 permit the distance between clutch-brake disk 151 and clutch rotor 163 a to be set and adjusted as needed. Each gap adjustment mechanism 172 comprises a wave spring 173 secured between a pair of washers 174 , and between the locknut 176 and the head of screw 175 . Thus, the gap adjustment mechanisms 172 act both to retain the brake shroud 155 and permit necessary adjustments, e.g., as clutch-brake disk 151 wears.

A second embodiment of a combination electric clutch-brake and generator is shown in FIGS. 4 and 5 , where generator 261 and clutch-brake assembly 262 are in a side-by-side relationship. FIG. 4 illustrates a riding vehicle 200 including a pair of electric wheel motors 239 L, 239 R to power a pair of driven wheels 216 L, 216 R. A set of caster wheels 212 is disposed at the front of frame 210 , which also supports a mowing deck 217 having a plurality of mowing blades 219 . Prime mover 220 , which may be an internal combustion engine, is also disposed on frame 210 near the rear thereof. In this second embodiment, vehicle 200 includes a standard belt and pulley system 223 that connects the output shaft 220 a of prime mover 220 with mowing blades 219 via clutch-brake assembly 262 . Controller 232 is operatively connected to battery 224 and to wheel motors 239 L, 239 R, and also supplies power to electric clutch-brake assembly 262 via conductor 226 . Generator 261 is connected to battery 224 by means of conductor 225 .

Generator 261 is disposed in a housing comprising upper generator housing member 267 and lower generator housing member 268 . As will be described in more detail below, upper generator housing member 267 includes a flange or extension 267 a . The shape of upper generator housing member 267 and its ability to serve multiple functions in this design help to minimize parts and reduce size of the overall unit. A stator 246 is fixed between upper generator housing member 267 and lower generator housing member 268 and incorporates coil windings formed in stator 246 in a known manner. Magnets 244 and 245 are fixed on upper rotor 242 and lower rotor 243 , respectively, to rotate adjacent stator 246 and generate an electric current in a known manner.

Generator drive belt 280 , and the two pulleys 281 , 282 are housed between a drive belt cover 279 and the upper generator housing member 267 which cooperate to form a transfer housing. Clutch-brake assembly 262 is directly connected to output shaft 220 a via a rotatable input member, namely input tube 263 , which also drives a driving pulley 281 . A generator drive belt 280 connects the driving pulley 281 to a driven pulley 282 which then rotates a second rotatable member, namely generator drive shaft 283 . It will be understood that although a timing belt system is shown, a standard belt and pulley system disposed in a similar transfer housing disposed above generator 261 and clutch-brake assembly 262 could be used in place of drive belt 280 and pulleys 281 , 282 .

Drive belt cover 279 also may include a plurality of mounting bosses 279 a spaced appropriately to permit drive belt cover 279 and the entire generator clutch-brake assembly 260 to be mounted to the bottom of prime mover 220 or to the vehicle frame 210 . Drive shaft 283 may be supported by upper bearing 284 located in drive belt cover 279 and lower bearing 285 in lower generator housing member 268 .

Electric clutch-brake assembly 262 is used to selectively connect output hub 253 and pulley 254 to input tube 263 . Input tube 263 also comprises clutch rotor 263 a formed therewith. Output shaft 220 a of prime mover 220 will also extend into the input tube 263 and is connected thereto by known means (not shown) to rotate therewith. Bearings, including upper bearing 264 in drive belt cover 279 and intermediate bearing 265 in upper generator housing member 267 , are used to support input tube 263 . A lower bearing 266 is located in output hub 253 to support rotation of output hub 253 and pulley 254 when the clutch is engaged.

As in the prior embodiment, a field coil 250 is used to activate the clutch function of the clutch-brake assembly 262 , as seen in FIG. 5 . Field coil 250 is fixed to an external surface 267 b of the flange or extension 267 a of upper generator housing member 267 to provide a compact arrangement. This arrangement reduces the overall height of the assembly 260 , thereby conserving ground clearance in utility vehicles such as riding vehicle 200 . Field coil 250 is powered by conductor 226 connected to controller 232 . Braking force is applied to output hub 253 by means of clutch-brake disk 251 , which is fixed to output hub 253 via leaf springs 252 and engages the inner surface of brake shroud 255 to provide the braking force. Leaf springs 252 bias the clutch-brake disk 251 to this braking position.

When field coil 250 is energized, clutch-brake disk 251 is magnetically pulled to engage clutch rotor 263 a , thereby engaging the output hub 253 and pulley 254 with input tube 263 to provide rotational output thereto. It will be understood that upper generator housing member 267 is shaped appropriately to permit brake shroud 255 to be secured thereto by a plurality of gap adjustment mechanisms 272 similar to that previously described. Gap adjustment mechanisms 272 are used to control the spacing between clutch-brake disk 251 and clutch rotor 263 a as needed.

A further embodiment of a combination electric clutch-brake and generator is shown in FIG. 6 , which illustrates a riding vehicle 300 similar to that shown in FIG. 4 in many respects, and including a pair of electric wheel motors 339 L, 339 R to power a pair of driven wheels 316 L, 316 R. A set of caster wheels 312 is disposed at the front of frame 310 , which also supports a mowing deck 317 having a plurality of mowing blades 319 . Prime mover 320 , which may be an internal combustion engine, is also disposed on frame 310 near the rear thereof. Vehicle 300 includes a standard belt and pulley system 323 that connects the output shaft 320 a of prime mover 320 with mowing blades 319 via a clutch-brake assembly that is operatively similar to clutch-brake assembly 262 . The primary difference between generator clutch-brake assembly 360 and the previously described generator clutch-brake assembly 260 is that the output shaft 320 a is directly connected to and drives the generator side of generator clutch-brake assembly 360 , permitting among other things a different orientation of generator clutch-brake assembly 360 with respect to vehicle frame 310 . Certain modifications to the structure of the generator clutch-brake assembly would be required to permit this variation, as would be understood by one of skill in the art. Controller 332 is operatively connected to battery 324 and to wheel motors 339 L, 339 R, and also supplies power to electric generator clutch-brake assembly 360 via conductor 326 , and the generator component is connected to battery 324 by means of conductor 325 .

While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalent thereof.