JP2012198041A - Slip structure for watch wheel and watch using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip structure for watch wheel which is operated easily stably for a long time even in the state where a slip torque between a gear part and a shank is high to a certain extent, and an analog watch with the same.SOLUTION: A slip structure 1 for a minute gear body structure 3 of an analog watch 5 comprises a ceramic bush 50 which is fitted to a shank 30, and a gear part 40 which is fitted to the bush 50 in an elastic engage portion. The gear part 40 is elastically friction-engaged to the bush 50 in the elastic engage part in such a manner that the gear part 40 and the bush 50 integrally move under operation of a torque smaller than a predetermined level and that the gear part 40 is rotated while slipping with respect to the bush 50 under operation of a torque larger than the predetermined level. Typically, the bush 50 is fitted into a recess 38 in a terminal of the shank 30 by a tubular part 52 at one end side, and the elastic engage portion of the gear part 40 is friction-engaged to a tubular part 51 at the other end side of the bush 50.

Description

  The present invention relates to a timepiece car slip structure and a timepiece using the same.

  When using an analog clock that displays the time with the hands, when adjusting the time to correct the display time, set the winding stem to the pull-out position, engage the handwheel and the small wheel, and operate the crown to set the winding stem. Rotate the minute wheel and hour hand by turning the hour wheel and hour wheel by turning the minute wheel through the wheel and the small wheel. In this needle alignment, a slip is generated between the hour pinion and the minute gear to prevent the rotation from being transmitted to the second wheel.

  Here, in the minute gear structure that is slip-engaged to the cylindrical pinion by the elastic arm portion of the minute gear, the pinion pin is used to keep the torque (slip torque) generated between the pinion pinion and the minute gear low. In order to reduce the friction between the gear and the split gear, it has been proposed to form a narrow-width portion that is easily bent in the elastic arm portion to keep the spring constant of the elastic arm portion low (Patent Document 1).

  However, if slip can occur between the pinion pinion and the gear portion even with a small torque as in Patent Document 1, the engagement between the small wheel and the spur wheel is released, and a rotational load is actually applied to the small wheel. In the normal hand movement state, when an unexpected external force is applied, the minute hand and the cylindrical pinion are easy to rotate with respect to the minute gear connected to the speed increasing side (load), and there is a high possibility that the minute hand will be displaced. It becomes difficult to lengthen the length.

  On the other hand, if the friction between the pinion pinion and the split gear is increased too much and the slip torque is increased too much, the torque required for needle alignment will increase, which may make it difficult to turn the crown. There is a possibility that the pin on the back of the sun may be broken or the pinwheel or small wheel may be scraped.

  In addition, in a state where the slip torque between the minute gear, which is a metal product, and the minute gear fitting portion of the cylindrical pinion is high, the surface pressure or the pressing force at the contact portion between the metal parts is high, and the gap between them is increased. Adhesion tends to occur, and the initial initial torque at the start of slip may increase due to the adhesion.

JP 2003-194964 A

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a slip for a timepiece that can be stably operated for a long period of time even when a slip torque between a gear portion and a shaft portion is high to some extent. The object is to provide a structure and an analog timepiece having the structure.

  A slip structure for a timepiece wheel according to the present invention includes a ceramic bush fitted to a shaft portion and a gear portion fitted to the bush at an elastic engagement portion to achieve the above object. The elastic force is applied so that the gear portion and the bush move integrally under the action of torque smaller than a predetermined level, and the gear portion slips and rotates with respect to the bush under the action of torque larger than the predetermined level. The engaging portion is elastically frictionally engaged with the bush.

  In the timepiece wheel slip structure of the present invention, since the gear portion is frictionally engaged with and fitted to the ceramic bush by the elastic engagement portion, the elastic engagement portion of the gear portion and the bush are Even when frictionally engaged with a relatively strong surface pressure, the ceramic bush and the gear portion (the elastic engagement portion thereof) are difficult to adhere to each other, so that the possibility of occurrence of whisker torque due to adhesion is low. Thus, the bush and the elastic engagement portion of the gear portion can be relatively strongly frictionally engaged. That is, an appropriate amount of slip torque acts between the bush and the elastic engagement portion of the gear portion. On the other hand, even if the minute hand is long, even if an unexpected external force is applied, the minute hand position shifts. On the other hand, unlike the case where adhesion occurs, there is little possibility that the slip torque becomes excessively high. Further, in the slip structure of the timepiece wheel according to the present invention, the bush that slips by being frictionally engaged with the elastic engagement portion of the gear portion is made of ceramic and has high wear resistance. Damage due to can be minimized. Also, by sufficiently reducing the surface roughness of the hard ceramic bush compared to metal, the wear of the elastic engagement portion of the gear portion frictionally engaged with the bush can be minimized. As a whole, wear of the slip portion (sliding portion) can be minimized.

  In the slip structure of a timepiece wheel of the present invention, typically, the bush is slip-engaged with the elastic engagement portion of the gear portion in a state where the bush is fitted to the metal shaft portion. Here, the fitting is performed by driving the bush into the shaft portion.

In the timepiece car slip structure of the present invention,
(1) Even if a bush is fitted around the end of the shaft,
(2) The bush may be fitted and fitted in the concave portion at the end of the shaft portion at the cylindrical portion on one end side.

  In the former case (ie, (1)), the elastic engagement portion of the gear portion is frictionally engaged with the outer periphery of the bush.

  In the latter case (ie, (2)), a compressive stress acts on the cylindrical portion on the one end side of the ceramic bush, so that the bush is easily kept stable. In the case of (2), typically, the elastic engagement portion of the gear portion is frictionally engaged with the cylindrical portion on the other end side of the bush.

  In the slip structure of a timepiece wheel according to the present invention, typically, the gear portion is slip-engaged with the outer peripheral surface of the tapered bush so that the diameter becomes larger toward the free end.

  In that case, a possibility that the gear portion may come off from the bush can be minimized. In this case, slip engagement of the gear portion with the bush is typically realized by driving the gear portion into the bush.

  In the slip structure of the timepiece wheel of the present invention, the bush is typically formed of at least one ceramic material selected from the group consisting of zirconia, alumina, and silicon carbide.

  In that case, the slip structure of the timepiece car tends to operate stably. Here, the zirconia is typically made of stabilized zirconia or partially stabilized zirconia having high toughness. The alumina is made of α-alumina and may be ruby. If desired, other oxides may be used instead of zirconia and alumina, and other carbides and nitrides may be used instead of silicon carbide.

  On the other hand, since the gear portion includes an elastic engagement portion, the gear portion is made of a metal material having high spring properties such as phosphor bronze, white or manganese-containing white bronze. However, as long as the elastic engagement portion can provide a sufficient surface pressure to generate a desired frictional engagement force, there is no possibility of adhesion with the ceramic material constituting the bush, and the ceramic material is configured. As long as the compatibility with the material to be used is low, other spring metal materials or plastics may be used.

  In the slip structure of a timepiece wheel of the present invention, typically, the gear portion is constituted by a split gear and the shaft portion is constituted by a cylindrical pinion.

  In that case, the hand can be aligned by operating the crown with an appropriate amount of force while avoiding blurring of the second hand or the like.

  The analog timepiece of the present invention has the above-described slip structure for a timepiece car in order to achieve the above object.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional explanatory view of an analog timepiece according to a preferred embodiment of the present invention having a minute gear structure having a slip structure according to a preferred embodiment of the present invention. FIG. 2 is an enlarged cross-sectional explanatory view of a minute gear structure of the analog timepiece of FIG. 1. FIG. 2 is an enlarged perspective view of a bush of the minute gear structure of the analog timepiece of FIG. 1. The perspective explanatory drawing similar to FIG. 3 about the modification of a bush. The perspective explanatory drawing similar to FIG. 3 about another modification of a bush. Cross-sectional explanatory drawing of the analog timepiece of another preferable one Example of this invention which has a split gear structure provided with the slip structure of another preferable one Example of this invention. FIG. 7 is an enlarged cross-sectional explanatory view of a minute gear structure of the analog timepiece of FIG. 6. FIG. 7 is an enlarged perspective explanatory view of a bush of the minute gear structure of the analog timepiece of FIG. 6. The perspective explanatory drawing similar to FIG. 8 about the modification of a bush.

  Several preferred embodiments of the present invention will be described based on preferred examples shown in the accompanying drawings.

  FIG. 1 shows an analog timepiece 5 as a timepiece according to a preferred embodiment of the present invention having a minute gear structure 3 provided with a slip structure 1 according to a preferred embodiment of the present invention.

  The analog timepiece 5 includes a wheel train 7 between the main plate 11 and the train wheel bridge 12 and on the dial 13 side of the main plate 11. The handwheel train 7 includes an hour wheel 20, a minute wheel structure 3, a second wheel 60 that can rotate around a central axis C, and a minute wheel 70. A central pipe 15 is attached to the through hole 14 that penetrates the base plate 11.

  The hour wheel 20 includes a relatively large-diameter cylindrical portion 21 and a hour gear or a cylindrical gear 22 that are rotatably fitted to the center pipe 15 on the dial 13 side of the main plate 11. An hour hand 24 is attached to the tip 23 of the cylindrical portion 21.

  As shown in FIG. 2, which is an enlarged sectional explanatory view of the minute wheel structure body 3 in addition to FIG. 1, the minute wheel structure body 3 includes a cylindrical pinion 30, a minute gear or second gear 40, and a cylindrical pinion 30. A bush 50 is connected to the second gear 40.

  As can be seen from FIGS. 1 and 2, the cylindrical pinion 30 is centered from the small gear portion or the second pinion portion 31 located on the train wheel bridge 12 side of the main plate 11 and the dial plate 13 side of the second pinion portion 31. It has a medium-diameter cylindrical portion 32 that penetrates through the pipe 15 and protrudes toward the dial plate 13, and a bush mounting portion 35 formed on the train wheel bridge 12 side of the second pinion portion 31. A minute hand 34 is attached to the protruding end portion 33 of the medium diameter cylindrical portion 32. The second gear 40 is slip-engaged with the cylindrical pinion 30 via the bush 50.

  That is, the cylindrical pinion 30 includes a recess 38 in the end surface 37 of the end 36 on the train wheel bridge 12 side, and a bush 50 is fitted in the recess 38.

  More specifically, the bush 50 includes a large-diameter cylindrical portion 51 and a small-diameter cylindrical portion 52 as can be seen from FIG. 3 of the perspective explanatory view showing the bush 50 in addition to FIGS. 1 and 2. The small diameter cylindrical portion 52 is fitted into the concave portion 38 of the cylindrical pinion 30 by driving. The large-diameter cylindrical portion 51 of the bush 50 includes a frustoconical circumferential surface or a tapered surface 53 that is slightly inclined so as to become thinner toward the dial 13 side (so as to become thicker toward the train wheel bridge 12 side). Here, in the bush 50, the surface roughness of the peripheral surface 53 of the large-diameter cylindrical portion 51 is low.

  The bush 50 is made of zirconia. However, it may be made of other ceramic materials such as alumina or silicon carbide.

  The second gear 40 is slip-fitted in the central hole 41 by driving into the tapered large-diameter cylindrical portion 51 of the bush 50. The corner 51a of the maximum diameter portion of the large diameter cylindrical portion 51 is chamfered to facilitate driving.

  The second gear 40 includes elastic arm portions 42 and 42 as elastic engagement portions, and a bush is formed at a central opening or a central hole portion 41 defined by opposing side surfaces of the central portions of the elastic arm portions 42 and 42. The outer peripheral surface 53 of 50 large-diameter cylindrical portions 51 is frictionally engaged. More specifically, the second gear 40 includes an annular gear main body 44 having a spur gear portion 43 on the outer periphery, and elastic arm portions 42 and 42 which are connected to the main body portion 44 at both ends and extend generally in the diametrical direction. Between the gear main body 44 and the elastic arm portions 42, 42, substantially semicircular openings 46, 46 that define the strength of the springs of the elastic arm portions 42, 42 are formed. Since the second gear 40 has the elastic arm portions 42, 42, the second gear 40 is made of an elastic metal material such as phosphor bronze, white or manganese-containing white bronze.

  In order to minimize the twisting of the elastic arm portions 42, 42 with respect to the extending plane of the second gear 40, the tapered outer peripheral surface 53 of the elastic arm portions 42, 42 forming the central hole 41 is provided. The inner side surfaces 47, 47 engaged with each other may also be composed of surfaces inclined in a truncated cone shape. The opening or hole 41 is typically generally circular as a whole, but is non-circular so as to contact the large-diameter cylindrical portion 51 only at a part of the inner side surfaces 47, 47 in the circumferential direction. May be. When the analog timepiece 5 is a normal wristwatch, the pressing force by which each elastic arm portion 42 elastically presses the outer peripheral surface 53 of the large-diameter cylindrical portion 51 of the bush 50 with the respective inner side surface 47 is, for example, 4-5N. In the minute gear structure 3 of the analog timepiece 5, it is difficult to ignore the possibility that adhesion occurs when the second gear 40 is slip-engaged directly with the cylindrical pinion 30. Since the bush 50 is made of a ceramic such as zirconia, there is practically no risk of adhesion. Therefore, the pressing force may be larger or smaller than about 4 to 5N.

  Returning to FIG. 1, the second wheel 60 includes a true part or a fourth true 61 that extends from the train wheel bridge 12 through the dial 13 along the central axis C, and four fourths 61 formed on the fourth true 61. A pinion 62 and a second gear or a fourth gear 63 attached to the fourth stem 61 are provided. A second hand 65 is attached to the protruding end portion 64 of the fourth stem 61 on the dial 13 side.

  The second gear 40 and the fourth pinion 62 are meshed with each other via the pinion portion 81 and the gear portion 82 of the third wheel & pinion 80, and the cylindrical gear 22 and the pinion portion 31 of the tube pinion 30 are They are meshed with each other via the pinion 71 and the reverse gear portion 72.

  When a pinion wheel 92 is fitted to the winding stem 90 extending in the lateral direction with respect to the main plate 11 and the winding stem 90 is in the drawing position P1 drawn in the A1 direction (FIG. 1), the prism of the winding stem 90 A pinion wheel 92 that rotates integrally with the portion 91 is meshed with the small wheel 75 by the tip side gear portion 93. The small iron wheel 75 is meshed with the minute wheel portion 72 (not shown). Therefore, according to the rotation in the B1 and B2 directions around the central axis B of the winding stem 90, the minute wheel 70 is rotated around the central axis E via the pinion wheel 92 and the small iron wheel 75. In response to the rotation of the minute wheel 70, the cylindrical gear 22 and the cylindrical pinion 30 are rotated. When the winding stem 90 is in the normal position (not shown) pushed in the A2 direction, the pinion wheel 92 is displaced in the A1 direction, and the pinion wheel 92 is a cylindrical portion (see FIG. (Not shown) and the winding stem 90 does not interfere with the rotation of the minute wheel 70.

  In the analog timepiece 5 having the split gear structure 3 including the slip structure 1 including the bush 50, the second gear 40 constituting the split gear structure 3 is formed by the small diameter cylindrical portion 52 in the concave portion 38 of the cylindrical pinion 30. The elastic engagement portion 42 in the form of an elastic arm portion forming a part of the peripheral wall of the hole portion 41 is frictionally engaged with the large-diameter cylindrical portion 51 of the fitted zirconia bush 50. Even when the elastic engagement portion 42 of the number gear 40 is engaged with the large-diameter cylindrical portion 51 of the bush 50 with a relatively strong radial pressing force and the friction force is relatively large, the second gear 40. Since the adhesion between the elastic engagement (arm) portion 42 and the large-diameter cylindrical portion 51 of the zirconia bush 50 is difficult to occur, the second gear 40 and the cylindrical pinion 30 to which the bush 50 is fitted are formed. When relative sliding occurs between the two after standing relatively stationary, Possibility is small that a large beard torque that prevents the re-occurs. Accordingly, a torque in the B1 or B2 direction is applied to the winding stem 90 set in the drawer transfer position P1 in the A1 direction, and the torque is applied to the elastic engagement portion 42 of the second gear 40 and the large-diameter cylindrical portion 51 of the bush 50. When the friction with the peripheral wall is exceeded, the cylindrical pinion 30 that meshes with the pinion portion 31 of the reverse gear 72 with the rotation of the hour wheel 92 and the minute wheel 70 according to the torque becomes the cylindrical pinion 30. Along with the fitted zirconia bush 50, the needle can be aligned by slip rotation with respect to the second gear 40. As a result, the fear that the tenon portions at the true ends of the minute wheel 70 may be bent or the wheel 92 or the small wheel 75 may be scraped can be minimized.

  Further, in the analog timepiece 5 having the split gear structure 3 provided with the bush 50, the elastic arm portion 42 as an elastic engaging portion forming the peripheral wall of the second gear 40 and the large-diameter cylindrical portion of the bush 50 made of zirconia. Since the elastic engagement portion 42 of the second gear 40 is engaged with the large-diameter cylindrical portion 51 of the bush 50 with a relatively strong radial pressing force without causing a risk of adhesion with the second gear 51. Since the pinion gear 40 and the zirconia bush 50 of the cylindrical pinion 30 can be relatively frictionally engaged, even if an unexpected external force is applied in the normal hand movement state, the second gear 40 and the zirconia bush of the pinion pinion 30 No slip is likely to occur between the two and 50, and there is little risk of needle skipping.

  Further, in the minute gear structure 3 of the analog timepiece 5, the bush 50 which is slipped by friction engagement with the metal second gear 40 is made of zirconia and has high wear resistance. However, damage due to wear can be minimized. Further, by reducing the surface roughness of the outer peripheral surface 53 of the hard zirconia bush 50 compared to metal, the wear of the elastic engagement portion 42 of the metal second gear 40 can be suppressed to a minimum, and as a whole The wear of the slip portions (sliding portions) 42 and 53 can be minimized.

  Since the large-diameter cylindrical portion 51 of the bush 50 to which the elastic engagement portion 42 of the second gear 40 is fitted has a tapered surface 53 that becomes thinner toward the small-diameter end portion 52 side, the second gear 40 is configured to be the bush. There is no possibility of coming off from the 50 large-diameter cylindrical portion 51.

  In the minute gear structure 3 of the analog timepiece 5, the small-diameter cylindrical portion 51 of the bush 50 is fitted into the concave portion 38 of the cylindrical pinion 30 by driving, so that the small-diameter cylindrical portion 51 is subjected to compressive stress. Therefore, the possibility that the bush 50 is broken can be minimized.

  In order to make sure that the bush is easily fitted into the concave portion 38 of the cylindrical pinion 30, instead of the bush 50 having the small-diameter cylindrical portion 52 having the cylindrical peripheral surface 54 as shown in FIG. Even the bush 50A having the small-diameter cylindrical portion 52A provided with the male thread portion 55 as shown in FIG. 4 has the small-diameter cylindrical portion 52B provided with the spline-like vertical groove 56 as shown in FIG. Bush 50B may be sufficient. If the needle is often turned clockwise during needle alignment, the threaded portion typically comprises a right-hand thread.

  When the bush 50A is fitted in place of the bush 50 in the peripheral wall of the concave portion 38 of the cylindrical pinion 30, typically, the male thread portion 55 of the small diameter cylindrical portion 52A of the bush 50A is screwed. When the bush 50B is fitted instead of the bush 50, the spline-like vertical groove portion 56 of the small-diameter cylindrical portion 52B of the bush 50B is typically pushed in the extending direction of the axis. In order to prevent the relative rotation, a complementary spline-like vertical groove portion extending in parallel with the extending direction of the axis to be fitted by driving or the like is provided.

  In the above, the example in which the small-diameter cylindrical portion of the bush is fitted into the concave portion of the cylindrical pinion has been described. Instead, as shown in FIGS. The convex portion may be fitted.

  In another embodiment shown in FIGS. 6 and 7, elements that correspond to the elements of the embodiment shown in FIGS. 1 and 2 but are different are denoted by the suffix D after the same reference numerals. .

  In the minute gear structure 3D of the analog timepiece 5D shown in FIGS. 6 and 7, the end portion 36D on the train wheel bridge 12 side of the cylindrical pinion 30D is a small diameter end portion 39, and the bush 50D is connected to the small diameter end portion 39. Is inserted by driving. That is, the bush mounting portion 35D of the cylindrical pinion 30D is composed of a small-diameter convex portion 39 in this example.

  Further, in the minute gear structure 3D of the analog timepiece 5D, the bush 50D is generally composed of an annular body 57 as a whole as shown in FIG. 8 in addition to FIGS. A small-diameter convex portion or a small-diameter end portion 39 forming a bush mounting portion 35D of the cylindrical pinion 30D is fitted on the substantially cylindrical inner peripheral surface 58 of the annular body 57 forming the bush 50D. The annular body 57 constituting the bush 50D is provided with an outer peripheral surface 59 in the form of a tapered surface or a frustoconical peripheral surface 53D, similar to the large-diameter cylindrical portion 51 of the bush 50. The second gear 40 is fitted in the hole 41 and slip-engaged with the elastic engagement portions 42 and 42. The corner 57a of the annular body 57 is chamfered similarly to the corner 51a.

  Also in the analog timepiece 5D having the split gear structure 3D having the slip structure 1D having the bush 50D, the second gear 40 forming the split gear structure 3D constituting the handwheel train 7D has a cylindrical pinion 30D. Friction engagement by elastic engagement portions 42 and 42 defining the hole 41 with respect to the outer peripheral surface 59 of the annular body 57 of the zirconia bush 50D fitted to the small diameter end portion 39 by the hole or the inner peripheral surface 58. Therefore, when the elastic engagement portion 42 of the second gear 40 is engaged with the outer peripheral surface 59 of the annular body 57 constituting the bush 50D with a relatively strong radial pressing force, the frictional force is relatively large. Even in such a case, the second gear 40 and the bush 50D are fitted to each other because adhesion hardly occurs between the elastic engagement portion 42 of the second gear 40 and the outer peripheral surface 59 of the annular body 57 of the zirconia bush 50D. Tatana Kana 30D Possibility is small that a large beard torque when relative sliding between the two from the state of being left pair to occur hinder the slip occurs. Accordingly, torque in the B1 or B2 direction is applied to the winding stem 90 set in the pulling position P1 in the A1 direction, and the torque is applied between the elastic engagement portion 42 of the second gear 40 and the outer peripheral wall of the annular body 57 of the bush 50D. When the friction between them exceeds the hour pinion wheel 92 according to the torque and the hour wheel 70, the hour pinion 30D meshed with the hour pinion gear 72 at the hour portion 31 is fitted into the hour pinion 30D. Together with the zirconia bush 50D, the second gear 40 slips and rotates. In this minute gear structure 3D, since the adhesion hardly occurs between the peripheral wall 42 of the second gear 40 and the large-diameter cylindrical portion 51 of the zirconia bush 50D, the second gear 40 and the bush 50D are fitted. At the time of slip rotation in which relative slip occurs between the cylinder pinion 30D and a relatively stationary state, there is little possibility that a large whisker torque will interfere with the slip, and an excessively large torque is applied. The needle alignment can be performed with a desired torque without applying.

  Also in the analog timepiece 5D using the minute gear structure 3D, there is no possibility of adhesion between the peripheral wall 42 of the second gear 40 and the annular body 57 constituting the ceramic bush 50D such as zirconia. Since the elastic engagement portion 42 of the second gear 40 is engaged with the annular body 57 forming the bush 50D with a relatively strong radial pressing force, the second gear 40 and the bush 50D made of zirconia having a cylindrical pinion 30D Therefore, even if an unexpected external force is applied in a normal hand-operated state, there is no risk of slippage between the second gear 40 and the cylindrical pinion 30D zirconia bush 50D. There is little risk of flying.

  Further, since the outer peripheral surface 59 of the annular body 57 of the bush 50D with which the elastic engagement portion 42 of the second gear 40 is frictionally engaged has a tapered surface 53D that becomes narrower toward the dial 13 side, the second gear There is no possibility that 40 will come off from the outer peripheral surface 59 of the annular body 57 constituting the bush 50D.

  In the minute gear structure 3D of the analog timepiece 5D, the annular body 57 forming the bush 50D is fitted into the small diameter end portion 39 of the cylindrical pinion 30D through the hole 58, so that the inner peripheral surface 58 side of the bush 50D is fitted. However, since the second gear 40 is fitted to the outer peripheral surface 59 of the annular body 57 constituting the bush 50D through the hole 41, excessive tension stress is suppressed to the bush 50D to a minimum. Therefore, even if the bush 50D is made of a ceramic material such as zirconia, the possibility that the bush 50D is broken can be reduced.

  In order to ensure that the bushing is easily fitted to the small diameter convex part 39 of the cylindrical pinion 30D, instead of the bushing 50D comprising the annular body 57 having the cylindrical inner peripheral surface 58 as shown in FIG. A bush 50E made of an annular body 57E having a cylindrical inner peripheral surface 58E provided with a spline-like vertical groove 58Ea as shown in FIG.

  Note that the outer peripheral wall of the small diameter convex portion 39 of the cylindrical pinion 30D is typically a spline-like vertical strip on the cylindrical inner peripheral surface 58E of the bush 50E when the bush 50E is fitted instead of the bush 50D. The groove portion 58Ea has a complementary spline-like longitudinal groove portion extending in parallel to the extending direction of the axis so that the groove 58Ea can be pushed in the extending direction of the axis to inhibit relative rotation.

1,1D slip structure 3,3D minute gear structure 5,5D analog timepiece 7,7D hand train wheel train 11 base plate 12 train train bridge 13 dial plate 14 through hole 15 central pipe 21 tubular portion 22 tubular gear 23 tip 24 hour hand 30, 30D cylindrical pinion 31 second pinion part 32 medium diameter cylindrical part 33 protruding end part 34 minute hand 35, 35D bush mounting part 36, 36D end part 37 end face 38 concave part 39 small diameter end part (small diameter convex part)
40 Second gear 41 Center hole (center opening)
42 Elastic arm (elastic engagement part)
43 Spur gear portion 44 Gear body portion 46 Opening portion 47 Inner side surface 50, 50A, 50B, 50D, 50E Bush 51 Large diameter cylindrical portion 51a Chamfered corner portions 52, 52A, 52B Small diameter cylindrical portion 53 Tapered surface (conical Trapezoidal surface)
54 Cylindrical peripheral surface 55 Male threaded portion 56 Spline-shaped vertical groove portion 57 Annular body 57a Chamfered corners 58, 58E Inner peripheral surface 58Ea Spline-shaped vertical groove portion 59 Outer peripheral surface 60 Second wheel 61 Fourth true 62 Fourth pinion 63 Fourth gear 64 Protruding end 65 Second hand 70 Date wheel 71 Kana portion 72 Date wheel 75 Small iron wheel 80 Third wheel 81 Kana portion 82 Gear portion 90 Winding stem 91 Square pillar portion 92 Pull wheel 93 Front side gear portion A1, A2 direction B1, B2 Rotation direction B, C Center axis P1 Pull-out position

Claims (8)

A ceramic bush fitted to the shaft,
A gear portion fitted to the bush in the elastic engagement portion, and under the action of torque smaller than a predetermined level, the gear portion and the bush move together under the action of torque larger than the predetermined level. Then, the timepiece wheel slip structure having the elastic engagement portion elastically frictionally engaged with the bush so that the gear portion slips and rotates with respect to the bush.   The timepiece car slip structure according to claim 1, wherein a bush is fitted around an end of the shaft portion.   The slip structure of a timepiece car according to claim 1, wherein a bush is fitted into a concave portion at an end of the shaft portion at a cylindrical portion on one end side.   The timepiece car slip structure according to claim 3, wherein the elastic engagement portion of the gear portion is frictionally engaged with the cylindrical portion on the other end side of the bush.   5. The timepiece car slip structure according to claim 1, wherein a gear portion is slip-engaged with an outer peripheral surface of a bush having a taper so that a diameter thereof becomes larger toward a free end.   The timepiece car slip structure according to any one of claims 1 to 5, wherein the bush is made of at least one ceramic material selected from the group consisting of zirconia, alumina, and silicon carbide.   The timepiece wheel slip structure according to any one of claims 1 to 6, wherein the gear portion includes a split gear, and the shaft portion includes a cylindrical pinion.   An analog timepiece comprising the slip structure according to any one of claims 1 to 7.

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