受験番号：22IPM019

問１[0002] A golf club (hereinafter referred to as a club) is mainly required to provide along distance shot and a shot that does not curve (or less likely to curve).

The

requirements of such characteristics to clubs are important, whereas golfers are also
very interested in finding clubs that fit themselves.

A typical club was manufactured

in consideration of static characteristics such as a length of a club shaft (hereinafterreferred to as a shaft), balance, a club weight, and a shaft flex, and golfers assessed,
imagined or only guessed the values of such characteristics from their past experiencesin order to select their clubs.
[0003] On the other hand, a golf swing is a dynamic behavior, and thus a clubselection has been focused on in consideration of dynamic characteristics, i.e., a specificvibration (which is a linear flexural specific vibration) of the club.

The amount of thisspecific vibration depends on a shaft flexural rigidity, a shaft weight, a shaft length, anda weight of a club head (hereinafter referred to as a head).

Specifically, during a downswing, a shaft is bent and recovered.

Thus, the head speed reaches the maximum when

the shaft is recovered and straight.

Therefore, if the ball is hit on this timing, themaximum distance of such swing can be obtained (if the face of the head is directed
correctly).

It is said that such a swing behavior relates to the specific vibration of agolf club.

A club having a specific vibration lower than the optimum reaches the hit

point before reaching the maximum head speed.

A club having a specific vibration

larger than the optimum reaches the fit point after reaching the maximum head speed,and this might end up with a lower distance and a bad shot direction.

1問２[0025] As illustrated in FIG. 3, if the flange 10 of the holder 7 is pressed onto the sidesurface of the outer ring 2, the friction produced on the contact surface therebetween
serves as a resistance against rotation of the holder 7.

If the friction exceeds the elastic

force of the elastic body 11, the inner ring 1 and the holder 7 rotate relative to eachother, and the roller 6 engages with the cylinder surface 3 and the cam surface 5, and therotation.

Then, the rotation of the inner ring 1 is transferred to the outer ring 2 throughthe roller 6.

The relative rotation between the inner ring 1 and the holder 7 also causes

elastic deformation of the elastic body 11.
[0026] If the axial load to the flange 10 is removed in a state in which the inner ring 1
and the outer ring 2 transfer the rotation torque to each other, the restoration elasticity ofthe elastic body 11 causes the holder 7 to rotate toward a neutral position.

Then, thisrotation removes the engagement of the roller 6 with the cylinder surface 3 and the cam
surface 5, and the inner ring 1 rotates alone.

The elastic body 11 is installed between

the inner ring 1 and the holder 7, and thus the roller 6 also revolves together with theholder 7.
[0027] During this time, the roller 6 is biased toward the inner periphery of the outerring 2 by the elasticity piece 9, and prevented from moving toward the inner direction of
the radius of the holder 7.

Thus, the behavior of the roller 6 is stable in a low-speedrotation of the inner ring 1, the drag torque applied to the holder 7 is small, and theroller 6 does not engage with the cylinder surface 3 and the cam surface 5 by mistake.
[0028] The elasticity piece 9 prevents the roller 6 from moving along the radiusdirection of the holder 7.

Thus, the roller 6 does not repeatedly collide with thecylinder surface 3 and the cam surface 5, and the vibration by the collision of the roller

26 hardly happen.

This provides a two-direction roller clutch having excellent vibration

characteristics.

問３1.

An electromagnetic bearing (10) for an axial force member (11)including a rotation shaft (12) and a distal region extending outwardly from the rotation
shaft (12),the electromagnetic bearing (10) comprising:a ring-shaped magnetic metal member (14) including a single coil (15) and apair of protrusions (20, 21),the magnetic metal member (14) sandwiching the distal region of theaxial force member (11),the protrusions (20, 21) each having a facing surface facing the axialforce member (11),the facing surface defining a magnetic flux control gap at each end of
the axial force member (11) along a rotation axis thereof,
the coil (15) generating a electromagnetic control magnetic flux
passage (22) through the magnetic flux control gap, andthe axial force member (11) being accordingly positioned in an axial
direction of electromagnetic bearing (10) relative to the magnetic metal member (14);andpair of ring-shaped permanent magnets (16, 17) attached on the magnetic metal
member (14) and each having a facing surface facing the axial force member (11),the permanent magnets (16, 17) defining pair of magnetic gaps remote3

from the magnetic flux control gaps in a diameter direction of the electromagnetic
bearing (10),the pair of ring-shaped permanent magnets (16, 17) being each parallelwith the electromagnetic control magnetic flux passage (22) through the pair ofmagnetic gaps, andthe permanent magnets (16, 17) generating bias magnetic flux
passages (18, 19) each including a passage, at least half of which is different from theelectromagnetic control magnetic flux passage (22).

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