1. A headphone set comprising:
a speaker housing which incorporates a speaker unit capable of outputting a sound, and is brought into contact with a user;
a connecting portion connected to the speaker housing in a state where the speaker housing is movable approximately linearly in a forward and rearward direction of the user;
a headband which mounts the connecting portion on an end portion and is wearable on a head of the user in a direction toward a crown of the head of the user; and
an ear pad, wherein:
the ear pad has an approximately elliptical shape,
the speaker housing and the headband are connected to each other with a predetermined angle \u03b1 formed between a direction of a center axis of the headband and a long axis direction of the ear pad in a state where the center axis of headband extends in a vertical direction, and
0<\u03b1<45\xb0.
2. The headphone set according to claim 1, wherein the ear pad in included in the speaker housing and substantially wraps an ear of the user.
3. The headphone set according to claim 1, wherein the speaker housing has a restriction on a wearable direction.
4. The headphone set according to claim 2, wherein the ear pad is made of a material capable of suppressing an amount of leakage of a sound output from the speaker unit to the outside of the speaker housing.
5. The headphone set according to claim 1, wherein the connecting portion is connected to the speaker housing in a state where the speaker housing is movable approximately linearly such that a position of the connecting portion is relatively raised with movement in the forward direction of the user, and is relatively lowered with movement in the rearward direction of the user.
6. The headphone set according to claim 1, wherein the connecting portion further includes a rotary shaft which rotates the speaker housing, and movement of the connecting portion in the forward and rearward direction is accompanied with feeling of resistance harder than feeling of resistance in the rotation of the speaker housing by the rotary shaft.
7. The headphone set according to claim 1, wherein the connecting portion and the speaker housing respectively have scales.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A drive device for erosion tools, comprising: a drive shaft, an electrode holder connected to the drive shaft, an axial drive which acts on the drive shaft, a rotational drive which acts on the drive shaft with magnetic contact, and a radial bearing; wherein the radial bearing is in the form of a ball track.
2. The drive device according to claim 1; wherein the ball track has a ball bearing race having a plurality of circular rows of balls which are separated a distance apart on the periphery.
3. The drive device according to claim 2; wherein the bails of the ball track are disposed directly on an outer periphery of the drive shaft.
4. The drive device according to claim 2, wherein the bearing race is comprised of plastic material.
5. The drive device according to claim 2; wherein the ball track has a bushing, wherewith the balls rest against an interior periphery of the bushing.
6. The drive device according to claim 1; wherein the direct drive comprises a synchronous motor, wherewith the drive shaft is constantly supplied with magnetization via permanent magnets.
7. The drive device according to claim 6; wherein the direct drive is a torque motor.
8. The drive device according to claim 1; wherein the axial drive has a ring shape, and surrounds the drive shaft.
9. The drive device according to claim 8; wherein the axial drive surrounds the ball track at least on one axial segment.
10. The drive device according to claim 1; wherein the axial drive is a piezo drive.
11. The drive device according to claim 10; wherein the piezo drive has a ring-shaped piezo actor.
12. The drive device according to claim 10; wherein the piezo drive has three stacked actors disposed symmetrically around the drive shaft.
13. The drive device according to claim 12; wherein the three stacked actors are interconnected in a zero-play and frictionless manner via solid linking bodies.
14. The drive device according to claim 1; wherein a spring-loaded disc which is disposed between the axial drive and a housing segment, under stress, and which axially pre-stresses the axial drive.
15. The drive device according to claim 1; wherein the drive shaft is in the form of a hollow shaft.
16. The drive device according to claim 3; wherein the bearing race is comprised of plastic material.
17. The drive device according to claim 16; wherein the ball track has a bushing, wherewith the balls rest against an interior periphery of the bushing.
18. The drive device according to claim 17; wherein the direct drive comprises a synchronous motor, wherewith the drive shaft is constantly supplied with magnetization via permanent magnets.
19. The drive device according to claim 1; wherein the axial drive has a ring shape, and surrounds the drive shaft.
20. The drive device according to claim 19; wherein the axial drive is a piezo drive.