Exercise resistance device with magnets

An exercise resistance device for use in an exercise apparatus includes a rotatable shaft and an impeller rotatable within a fluid filled sealed chamber. A rotating member is joined for rotation with the rotatable shaft. The rotating member is external to the sealed chamber and is magnetically coupled to the impeller.

BACKGROUND OF THE INVENTION

The present invention relates generally to a resistance device for use with exercise equipment and, more particularly, to a resistance device for bicycle trainers.

Bicycle trainers have been used by bicycle enthusiasts to convert their bicycles for stationary riding. A typical user is a bicycle owner who competes in various bicycles races or rides often. When the weather prevents riding outdoors, such as when it is raining, too cold, or too hot, the cyclist can use the trainer indoors to simulate a ride. In some cases, cyclists may want to use a trainer while also reading or watching television. However, in all cases, the bicycle trainer should be easy to use and simulate bicycle riding on the open road.

A common bicycle trainer has a frame onto which the user mounts the bicycle. Typically, the rear wheel of the bicycle is in contact with a roller that, in turn, is coupled to a resistance unit. The resistance unit provides increasing resistance to match the energy output of the rider. Some resistance devices use fluid as a resistance medium. However, a significant problem of current fluid resistance units is that they can leak, which can damage or stain the surface upon which it rests.

SUMMARY OF THE INVENTION

An exercise resistance device for use in an exercise apparatus includes a rotatable shaft and an impeller rotatable within a fluid filled sealed chamber. A rotating member is joined for rotation with the rotatable shaft. The rotating member is external to the sealed chamber and is magnetically coupled to the impeller.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

FIG. 1illustrates a bicycle trainer1having a U-shaped frame2and legs3. The legs3can fold in towards frame2to allow bicycle trainer1to be easily stored. Referring also toFIG. 2, a rear wheel9of a bicycle8is held in place by clamps4and5. Handles6are provided to move the clamps4and5to engage the bicycle8and hold it upright.

A resistance unit is shown generally at10. In the embodiment illustrated, the resistance unit10includes a roller or a shaft20that is coupled to a flywheel30and an impeller unit100on opposite sides thereof. The rear wheel9of the bicycle8is in friction contact with the roller20. It should be noted that the frame2, the legs3and the clamps4and5are but one suitable embodiment wherein other frame configurations can be used to maintain the bicycle8and rider in a stable, upright position.

Referring toFIG. 3, the impeller unit100includes an impeller101located within enclosed chamber walls103, forming a sealed chamber103A. External to the chamber103A, but magnetically coupled to the impeller101, is a rotating member104that is directly coupled to the roller20to rotate therewith. The flywheel30is also provided and coupled to the roller20to rotate therewith, if needed.

The impeller101is disposed within the chamber103A to rotate therein. In the embodiment illustrated, at least one and preferably a plurality of magnets101A are secured to or molded within the impeller101on a disk portion101B thereof. Similarly, at least one and preferably a plurality of magnets104A are provided on the rotating member104or molded therein. In one embodiment, the plurality of magnets101A and104A are spaced approximately 0.110 inches apart. However, a wall portion103C, partially defining the chamber103A, extends between the impeller101and the rotating member104. The wall portion103C can be formed from a non-magnetic material, such as plastic, fiberglass or ceramic. In the example provided above, where the magnets are 0.110 inches apart, the wall portion103C can be 0.06 inches thick.

The impeller101is mounted within the chamber103A so as to rotate therein. In the embodiment illustrated, the impeller101is mounted to a cap107with a mounting bolt108and a bearing109. The cap107is joined to the chamber walls103and sealed therewith using an O-ring seal110to form the sealed chamber103A. A stationary vane assembly111is provided in the chamber103A, for example, integrally formed with the cap107. Ports120are provided to fill the chamber103. A fluid, such as silicone (e.g., having a viscosity approximately equal to 50 centistrokes) is provided in the chamber103A to provide resistance between the impeller101and the vane assembly111. The amount of fluid within the chamber103A can be varied to change the resistance. In addition, the number of vanes on the vane assembly111and the impeller101can be varied to obtain the desired resistance.

In the embodiment illustrated, an outer housing122is joined to the chamber walls103to enclose the rotating member104. Fins124can be provided on the outer housing122and the cap107for cooling purposes.

In the embodiment illustrated, although other configurations can be used, a center shaft130extends from the rotating member104to the flywheel30and is secured thereto with a nut32. The roller20is coupled to rotate with the shaft130using a setscrew134. Bearings136are provided to allow the shaft130to rotate on the frame2. Spacer bushings138and140are provided between the shaft130and the housing122, and the shaft130and the flywheel30, respectively.

The resistance unit10described herein provides a sealed chamber103A wherein the impeller101can rotate therein, being driven by the rotating member104in a non-contact, magnetically coupled manner. In the embodiment illustrated, no rotating seals are used, but rather, a stationary seal is provided, for example, by the O-ring seal110. The stationary seal significantly reduces the possibility of leaks.

FIGS. 4-18are views of many of the components described above.

FIGS. 19 and 20illustrate a second embodiment of an impeller unit150. The impeller unit150includes an impeller151located within enclosed walls153, forming a sealed chamber153A. Like the impeller101, the impeller151is magnetically coupled to a rotating member154that is directly coupled to the roller20.

The impeller151can be formed from a high-permeability magnet material; however, in this embodiment, the plurality of magnets101A are joined to a separate portion155. As used herein “high-permeability magnetic material” shall mean a material used to concentrate magnetic flux from the magnets along a desired path. Commonly, such a material is ferromagnetic, for example, iron or steel, although other materials can also be used. The magnets101A can be secured to the high-permeability magnetic material, herein embodied as a plate155, using magnetic attraction although an adhesive such as available from the Loctite Corporation of Rocky Hill, Conn., can also be used. The rotating member154can be constructed in a similar manner with the plurality of magnets104A secured to a high-permeability plate157.

The enclosed walls153forming the sealed chamber153A include a bowl portion156and a plate member158. The bowl portion156includes the stationary vanes111. The plate member158is held against a stationary seal160by a support portion164with a plurality of fasteners166. The support portion164and the plate member158form a second chamber167in which the rotating member154rotates. The plate member158is non-magnetic and can be formed from plastic, fiberglass or ceramic. In one embodiment, the plate member158is formed from Garolite™ available from McMaster-Carr of Chicago, Ill. The plate member158is generally thin, for example, 0.060 inches wherein 0.030 spacing can be provided between the plate member158and the magnets101A and104A.

In this embodiment, the impeller151is secured to the bowl portion156using a fastener170with thrust bearings172and174, spacer176and a washer178. As illustrated inFIG. 20, three opposed sets of vanes are formed between the impeller151and the stationary vanes111although more or less vanes can be used on the impeller151and rotating member154as desired.