受験番号：22IPM005
問１[0002]
Golf clubs (hereinafter referred to as clubs) are most required of attaining
large flying distances and high resistances to bending. Although such characteristics
are important for the clubs, golfers are greatly interested in selecting clubs suitable forthem. Clubs have been manufactured to date in consideration of static characteristics
such as the length of club shafts (hereinafter referred to as shafts), balance, club weight,
and shaft hardness, and golfers have no choice but to determine or guess suchcharacteristic values based on their experiences or select only by intuition.
[0003]On the other hand, based on the fact that a golf swing is a dynamic behavior,selection of clubs in consideration of dynamic characteristics of clubs, that is, eigen
frequency (that refers to a primary binding eigen frequency), has attracted attention.
The eigen frequency depends on flexural rigidity of a shaft, shaft weight, shaft length,
and weight of a club head (hereinafter referred to as a head), which is summarized asfollows. Specifically, a shaft warps and recovers in a down swing, and the head speed
is supposed to be at maximum when the shaft recovers to be straight. Thus, if the clubhits a ball at this point of time, the maximum flying distance in this swing can beobtained. (As long as the face of the head is appropriately oriented), such swing
behavior is supposed to be affected by the eigen frequency of the golf club. In the caseof using a club having an eigen frequency lower than an optimum eigen frequency, theclub hits the ball before the maximum head speed. On the other hand, in the case ofusing a club having an eigen frequency higher than the optimum eigen frequency, theclub hits the ball after the maximum head speed. In either case, the ball is expected tofly in an insufficient distance to an insufficient direction.

問２[0025]
As illustrated in FIG. 3, when the flange 10 of the cage 7 is pressed against aside surface of the outer race 2, a frictional force is generated on the contact surface toserve as a rotational resistance of the cage 7. When the frictional force then exceeds
an elastic force of the elastic body 11, relative rotation of the inner race 1 and the cage 7
occurs, and the roller 6 is engaged with the cylinder surface 3 and the cam surface 5 sothat rotation of the inner race 1 is transferred to the outer race 2 through the roller 6.
The relative rotation of the inner race 1 and the cage 7 elastically deforms the elastic
body 11.
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[0026]
While a rotational torque is being transferred from the inner race 1 to theouter race 2, when an axial load applied to the flange 10 is canceled, the elastic body 11
elastically recovers to cause the cage 7 to rotate toward a neutral position. Thisrotation cancels the engagement of the roller 6 with the cylinder surface 3 and the cam
surface 5 so that idle rotation of the inner race 1 occurs. Since the elastic body 11 isinterposed between the inner race 1 and the cage 7, the roller 6 revolves together withthe cage 7.
[0027]At this time, the roller 6 is biased by the elastic piece 9 toward the innerperiphery of the outer race 2 so that movement of the roller 6 in a radially inward
direction of the cage 7 is reduced or prevented. Accordingly, while the inner race 1rotates at a low speed, the roller 6 behaves stably, and a small drag torque is applied tothe cage 7. Thus, the roller 6 is not erroneously engaged with the cylinder surface 3
and the cam surface 5.
[0028]In addition, since the elastic piece 9 reduces or prevents movement of theroller 6 in a radial direction of the cage 7, the roller 6 does not repeatedly collide withthe cylinder surface 3 and the cam surface 5, and vibrations due to collision of the roller
6 hardly occur. As a result, a two-way roller clutch with excellent vibration
characteristics can be obtained.
問３
1.
An electromagnetic bearing (10) for an axial member (11) including a rotation
shaft (12) and having a distal region extending outward from the rotation shaft (12), theelectromagnetic bearing (10) comprising:a magnetic iron-based member (14) including a coil (15) and a pair ofprojections (20, 21) and extending over the distal region of the axial member (11), thepair of projections (20, 21) having opposed surfaces opposed to the axial member (11),the opposed surfaces defining a magnetic flux control gap at each axial end in therotation of the axial member (11), the coil (15) being configured to generate anelectromagnetic control magnetic flux passage (22) through the magnetic flux control
gap so that the axial member (11) is positioned in an axial direction with respect to themagnetic iron-based member (14); anda pair of annular permanent magnets (16, 17) mounted on the magnetic
iron-based member (14), having opposed surfaces opposed to the axial member (11),and defining a pair of magnetic gaps at locations radially separated from the magnetic
flux control gap, the pair of annular permanent magnets (16, 17) being configured togenerate, through the pair of magnetic gaps, bias magnetic flux paths (18, 19) parallel to2the electromagnetic control magnetic flux passage (22) and each different from theelectromagnetic control magnetic flux passage (22) in a portion longer than a half of alength thereof.

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