EP2251746A2

EP2251746A2 - Timepiece Wheel and Timepiece

Info

Publication number: EP2251746A2
Application number: EP10160149A
Authority: EP
Inventors: Takuya Murazumi
Original assignee: Seiko Instruments Inc
Current assignee: Seiko Instruments Inc
Priority date: 2009-05-11
Filing date: 2010-04-16
Publication date: 2010-11-17
Also published as: JP2010261906A; EP2251746A3

Abstract

The present invention aims to provide a timepiece wheel of high wear resistance and superior in durability. The present invention provides a timepiece wheel 130 comprising: a base material 132 formed as a wheel of a metal allowing anodic treatment; and an anodic oxide film 133 formed on the surface of the base material through anodic treatment.

Description

The present invention relates to a timepiece wheel and a timepiece equipped with the same.
A great number of timepiece wheels are used in a timepiece such as a mechanical timepiece. Such timepiece wheels are formed in various shapes according to their uses; and they are combined with each other in a complicated manner to transmit power. In particular, high wear resistance is required of a timepiece wheel since it undergoes sliding a large number of times. In order to achieve an improvement in terms of durability and to enable timepieces to tick away the time more accurately, there is going to be a demand for a further improvement in terms of wear resistance.
Generally speaking, as methods for improving the wear resistance of a timepiece wheel, there are known, for example, a method in which a base material is coated with a protective film through thermal oxidation processing (See Patent Document JP-T-2008-544290 ), and a method in which a base material is coated with a protective film through physical vapor deposition (PVD). By thus covering a base material with a protective film, the base material is protected from wear, thereby achieving an improvement in terms of wear resistance.
However, with the conventional methods, it has been rather difficult to secure sufficient wear resistance. This will be illustrated in detail below.
First, the protective film formed by the conventional methods exhibits a high level of hardness; in particular, the protective film formed by PVD processing is a film of a very high level of hardness. In Vickers hardness (Hv), it exhibits a high hardness level of 1500 to 3000. On the other hand, the protective film formed by the conventional methods is characterized by high residual stress. Thus, there is nothing for it but to increase the film thickness. If the film thickness is increased, high residual stress is allowed to be accumulated, resulting in a large difference in stress between the film and the base material. Due to this difference in stress, it is highly probable that there are generated in the protective film cracks, fissures, etc. attributable to self-destruction. Accordingly, the film thickness of the protective film has to be as small as approximately 0.1 µm to 2 µm. However, due to this small film thickness, it is highly probable that even a protective film formed as a high hardness coating film is peeled off by rubbing, an impact or the like. As a result, as stated above, it is rather difficult to secure sufficient wear resistance.
Further, in the conventional methods, the strength with which the protective film is held in intimate contact with the base material is rather low, so that the possibility of the protective film being peeled off is high. Usually, the contact intimacy is enhanced as the processing temperature at the time of formation of the protective film increases; however, that is likely to adversely affect the base material (through thermal deformation, etc.), so that the processing temperature cannot be increased. Thus, it is rather difficult to enhance the strength with which the protective film is held in intimate contact with the base material. Thus, the protective film is subject to peeling off; thus, in this respect also, it is difficult to secure sufficient wear resistance.
It is an aspect of the present invention to provide a timepiece wheel exhibiting high wear resistance and superior in durability, and a timepiece equipped with the same.
To achieve the above aspect, the present invention provides the following means.
(1) In accordance with the present invention, there is provided a timepiece wheel comprising a base material formed as a wheel of a metal allowing anodic treatment, and an anodic oxide film formed on the surface of the base material through anodic treatment.
In the timepiece wheel of this invention, the surface of a base material formed as a wheel is coated with an anodic oxide film. In addition to being a coating film of high hardness, this anodic oxide film is characterized by low residual stress at the time of coating. Thus, unlike the conventional film, it does not easily generate a great difference in stress between itself and the base material even if the thickness of the anodic oxide film is increased, so that cracks and fissures are not easily generated. Thus, it is possible to coat the surface of the base material with an anodic oxide film of a sufficient thickness (e.g., ten and several µm), which has been impossible with the prior art. As a result, it is possible to protect the base material with an anodic oxide film of high hardness and sufficient thickness.
Further, unlike a film simply formed on the base material, the anodic oxide film is an oxide formed on the surface of the base material by oxidation reaction through anodic treatment. Thus, the anodic oxide film can exert high intimate contact strength, making it possible to enhance the intimacy with which the base material is held in contact with the anodic oxide film. Thus, even if it is subjected to rubbing, an impact or the like, the anodic oxide film is not easily peeled off from the base material.
In this way, it is possible to provide a timepiece wheel consisting of a base material whose surface is coated with an anodic oxide film of high hardness and sufficient thickness with high intimate contact strength. Thus, it is possible to achieve an enhancement in wear resistance, and to achieve an improvement in durability.
(2) According to the present invention, there is provided a timepiece wheel as described above characterized in that the base material is formed in a uniform thickness all over.
In the timepiece wheel of this invention, an enhancement in wear resistance is achieved by the anodic oxide film, so that there is no need to take general measures for achieving an improvement in wear resistance, such as provision of a step portion (oil sump) for retaining lubricating oil or the like. Thus, it is possible to form the base material in a uniform thickness all over, and to reduce its thickness itself.
Thus, it is possible to achieve a reduction in the weight of the timepiece wheel, and to improve its mobility as a wheel, making it possible to achieve an enhancement in operational efficiency.
(3) According to the present invention, there is provided a timepiece wheel as described above characterized in that the anodic oxide film is impregnated with lubricating oil.
In the timepiece wheel of this invention, the anodic oxide film is impregnated with lubricating oil, so that it is possible to achieve an enhancement in lubrication property, making it possible to achieve a further enhancement in wear resistance.
(4) According to the present invention, there is provided a timepiece equipped with a timepiece wheel according to the present invention as described above.
The timepiece of the present invention is equipped with a timepiece wheel of high wear resistance and improved in durability, so that it is possible to provide a high quality timepiece of high operational reliability capable of ticking away the time accurately for a long period of time.
With a timepiece wheel according to the present invention, it is possible to achieve an enhancement in wear resistance and to achieve an improvement in durability.
Further, with a timepiece according to the present invention, due to the provision of the timepiece wheel as described above, it is possible to provide a high quality timepiece of high operational reliability capable of ticking away the time accurately for a long period of time.
Embodiments of the present invention will now be described by way of further example only and with reference to the accompanying drawings, in which:

FIG. 1 is a front side plan view of a movement of a mechanical timepiece with an escape wheel & pinion constituting a timepiece wheel according to the present invention (with part of the components thereof omitted and a bridge member indicated by phantom lines).
FIG. 2 is a schematic partial sectional view of a portion extending from a movement barrel to the escape wheel & pinion of the movement shown in FIG. 1.
FIG. 3 is a schematic partial sectional view of a portion extending from the escape wheel & pinion to a balance with hairspring of the movement shown in FIG. 1.
FIG. 4 is a plan view of the escape wheel & pinion and a pallet fork forming the movement shown in FIG. 1.
FIG. 5 is an enlarged perspective view of a tooth portion of the escape wheel & pinion shown in FIG. 4.
FIG. 6 is a plan view of the front side of a movement of an automatic timepiece having a timepiece wheel according to the present invention.
FIG. 7 is a schematic partial sectional view of a portion of the movement shown in FIG. 6 extending from a movement barrel to a ball bearing.

In the following, an embodiment of the present invention will be described with reference to FIGs. 1 through 5. In the description of this embodiment, a mechanical timepiece is taken as an example of the timepiece, and an escape wheel & pinion is taken as an example of the timepiece wheel.
First, the mechanical timepiece will be described with reference to FIGs. 1 through 3. FIG. 1 is a plan view of the movement front side. FIG. 2 is a schematic partial sectional view of the portion extending from the movement barrel to the escape wheel & pinion. FIG. 3 is a schematic partial sectional view of the portion extending from the escape wheel & pinion to the balance with hairspring.
As shown in FIGs. 1 through 3, a mechanical timepiece 1 is equipped with a movement 100. The movement 100 has a main plate 102 constituting the substrate of the movement 100. A winding stem 110 is rotatably incorporated into a winding stem guide hole 102a of the main plate 102. A dial 104 (See FIGs. 2 and 3) is mounted to the movement 100.
Generally speaking, of both sides of the main plate 102, the side where the dial 104 is arranged is referred to as the back side of the movement 100, and the side opposite to the side where the dial 104 is arranged is referred to as the front side of the movement 100. A train wheel assembled to the front side of the movement 100 is referred to as the front train wheel, and a train wheel assembled to the back side of the movement 100 is referred to as the back train wheel.
The position of the winding stem 110 in the axial direction is determined by a switching device including a setting lever 190, a yoke 192, a yoke spring 194, and a setting lever jumper 196. A winding pinion 112 is rotatably provided on the guide shaft portion of the winding stem 110. When, with the winding stem 110 being at a first winding stem position (0th step), which is nearest to the inner side of the movement 100 as measured along the rotation axis, the winding stem 110 is rotated, the winding pinion 112 is rotated through rotation of a clutch wheel. A crown wheel 114 is rotated through rotation of the winding pinion 112. A ratchet wheel 116 is rotated through rotation of the crown wheel 114. Through the rotation of the ratchet wheel 116, a mainspring 122 (See FIG. 2) accommodated in a movement barrel 120 is wound up.
A center wheel & pinion 124 is rotated through rotation of the movement barrel 120. An escape wheel & pinion 130 is rotated through rotation of a second wheel & pinion 128, a third wheel & pinion 126, and the center wheel & pinion 124. The movement barrel 120, the center wheel & pinion 124, the third wheel & pinion 126, and the second wheel & pinion 128 constitute the front train wheel.
An escapement/governor device for controlling the rotation of the front train wheel is formed by a balance with hairspring 140, the escape wheel & pinion 130, and a pallet fork 142. As shown in FIG. 3, the balance with hairspring 140 is equipped with a balance staff 140a and a hairspring 140c. As shown in FIG. 2, based on the rotation of the center wheel & pinion 124, a cannon pinion 150 rotates simultaneously. And, a minute hand 152 mounted to the cannon pinion 150 indicates "minute."
Further, the cannon pinion 150 is equipped with a slip mechanism for the center wheel & pinion 124. Based on the rotation of the cannon pinion 150, an hour wheel 154 is rotated through rotation of a minute wheel. And, an hour hand 156 mounted to the hour wheel 154 indicates "hour."
As shown in FIG. 3, the hairspring 140c is a spiral (helical) thin-plate spring having a plurality of turns. The inner end portion of the hairspring 140c is fixed to a collet 140d fixed to the balance staff 140a. On the other hand, the outer end portion of the hairspring 140c is fixed in position by a screw via a stud 170a mounted to a stud support 170 fixed to a balance bridge 166 (See FIG. 1 ).
A regulator 168 is rotatably mounted to the balance bridge 166. The balance with hairspring 140 is rotatably supported with respect to the main plate 102 and the balance bridge 166.
As shown in FIG. 2, the movement barrel 120 is equipped with a barrel wheel 120d, a barrel arbor 120f, and the mainspring 122. The barrel arbor 120f is equipped with an upper shaft portion 120a and a lower shaft portion 120b. The barrel arbor 120f is formed of a metal such as carbon steel. The barrel wheel 120d is formed of a metal such as brass.
The center wheel & pinion 124 is equipped with an upper shaft portion 124a, a lower shaft portion 124b, a pinion portion 124c, a wheel portion 124d, and a bead portion 124h. The pinion portion 124c of the center wheel & pinion 124 is formed so as to be in mesh with the barrel wheel 120d. The upper shaft portion 124a, the lower shaft portion 124b, and the bead portion 124h are formed of a metal such as carbon steel. The wheel portion 124d is formed of a metal such as nickel.
The third wheel & pinion 126 is equipped with an upper shaft portion 126a, a lower shaft portion 126b, a pinion portion 126c, and a wheel portion 126d. The pinion portion 126c of the third wheel & pinion 126 is formed so as to be in mesh with the wheel portion 124d.
The second wheel & pinion 128 is equipped with an upper shaft portion 128a, a lower shaft portion 128b, a pinion portion 128c, and a wheel portion 128d. The pinion portion 128c of the second wheel & pinion 128 is formed so as to be in mesh with the wheel portion 126d. The upper shaft portion 128a and the lower shaft portion 128b are formed of a metal such as carbon steel. The wheel portion 128d is formed of a metal such as nickel.
The escape wheel & pinion 130 is equipped with an upper shaft portion 130a, a lower shaft portion 130b, an escape pinion portion 130c, and an escape wheel portion 132. The escape pinion portion 130c is formed so as to be in mesh with the wheel portion 128d.
As shown in FIG. 3, the pallet fork 142 is equipped with a body of pallet fork 142d and a pallet staff 142f. The pallet staff 142f is equipped with an upper shaft portion 142a and a lower shaft portion 142b.
As shown in FIG. 2, the movement barrel 120 is rotatably supported with respect to the main plate 102 and the barrel bridge 160. That is, the upper shaft portion 120a of the barrel arbor 120f is rotatably supported with respect to the barrel bridge 160. The lower shaft portion 120b of the barrel arbor 120f is rotatably supported with respect to the main plate 102.
The center wheel & pinion 124, the third wheel & pinion 126, the second wheel & pinion 128, and the escape wheel & pinion 130 are rotatably supported with respect to the main plate 102 and the train wheel bridge 162. That is, the upper shaft portion 124a of the center wheel & pinion 124, the upper shaft portion 126a of the third wheel & pinion 126, the upper shaft portion 128a of the second wheel & pinion 128, and the upper shaft portion 130a of the escape wheel & pinion 130 are each rotatably supported with respect to the train wheel bridge 162. The lower shaft portion 124b of the center wheel & pinion 124, the lower shaft portion 126b of the third wheel & pinion 126, the lower shaft portion 128b of the second wheel & pinion 128, and the lower shaft portion 130b of the escape wheel & pinion 130 are each rotatably supported with respect to the main plate 102.
As shown in FIG. 3, the pallet fork 142 is rotatably supported with respect to the main plate 102 and the pallet bridge 164. That is, the upper shaft portion 142a of the pallet fork 142 is rotatably supported with respect to the pallet bridge 164. The lower shaft portion 142b of the pallet fork 142 is rotatably supported with respect to the main plate 102.
Lubricating oil is applied to the bearing portion of the barrel bridge 160 rotatably supporting the upper shaft portion 120a of the barrel arbor 120f, the bearing portion of the train wheel bridge 162 rotatably supporting the upper shaft portion 124a of the center wheel & pinion 124, the bearing portion of the train wheel bridge 162 rotatably supporting the upper shaft portion 126a of the third wheel & pinion 126, the bearing portion of the train wheel bridge 162 rotatably supporting the upper shaft portion 128a of the second wheel & pinion 128, the bearing portion of the train wheel bridge 162 rotatably supporting the upper shaft portion 130a of the escape wheel & pinion 130, and the bearing portion of the pallet bridge 164 rotatably supporting the upper shaft portion 142a of the pallet fork 142.
Further, lubricating oil is applied to the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 120b of the barrel arbor 120f, the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 124b of the center wheel & pinion 124, the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 126b of the third wheel & pinion 126, the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 128b of the second wheel & pinion 128, the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 130b of the escape wheel & pinion 130, and the bearing portion of the main plate 102 rotatably supporting the lower shaft portion 142b of the pallet fork 142.
As the above-mentioned lubricating oil, it is desirable to employ precision instrument oil, in particular, so-called timepiece oil.
In order to enhance the lubricating oil retaining performance, it is desirable to provide a conical, cylindrical, or truncated-cone-shaped oil sump portion at each bearing portion of the main plate 102, the bearing portion of the barrel bridge 160, and each bearing portion of the train wheel bridge 162. Providing these oil sump portions makes it possible to effectively prevent diffusion of oil due to the surface tension of the lubricating oil.
The main plate 102, the barrel bridge 160, the train wheel 162, and the pallet fork 164 may be formed of a metal such as brass, or a resin such as polycarbonate.
Next, the above-described escape wheel & pinion 130 will be illustrated in more detail.
As shown in FIGs. 4 and 5, the escape wheel & pinion 130 is composed of a metal base material 132 formed in a predetermined thickness, an anodic oxide film 133 covering the entire surface of the base material 132 through anodic treatment, and a shaft member 131 driven into the center of the base material 132.
FIG. 4 is a plan view of the escape wheel & pinion 130 and the pallet fork 142 in mesh with each other. It should be noted, however, that, in FIG. 4, the anodic oxide film 133 is omitted. FIG. 5 is an enlarged perspective view of a tooth portion 132a of the escape wheel & pinion 133.
The base material 132 is formed as a wheel of a material allowing anodic treatment, for example, aluminum (AI). More specifically, its upper and lower surfaces are formed as flat surfaces; further, it is formed in a uniform thickness all over, and has a plurality of tooth portions 132a formed in a special, hook-like configuration. Pallet jewels 144a, 144b of the pallet fork 142 described below come into contact with the distal ends of the plurality of tooth portions 132a. That is, the side surfaces of the distal end portions of the tooth portions 132a are formed as sliding surfaces (impact surfaces) 132b with which the pallet jewels 144a, 144b come into contact to slide thereon.
The anodic oxide film 133 is a high hardness coating film whose hardness in Hv (Vickers hardness) ranges approximately from 1600 to 2000, and covers the surface of the base material 132 in a sufficient thickness (ten and several µm).
The shaft member 131 is a member mounted by being driven into a retention hole (not shown) provided at the center of the base material 132; its center axis is identical with the center axis of the escape wheel & pinion 130. The above-mentioned upper shaft portion 130a is provided at the upper end portion of the shaft member 131, and the lower shaft portion 130b is provided at the lower end portion thereof. Further, an escape pinion portion 130c is provided below the upper shaft portion 130a. As stated above, the escape pinion portion 130c is in mesh with the wheel portion 128d of the second wheel & pinion 128, whereby the rotational force of the second wheel & pinion 128 is transmitted to the shaft member 131 to rotate the escape wheel & pinion 130.
A plurality of tooth portions 132a of the escape wheel & pinion 130, constructed as described above, are held in mesh with the pallet fork 142. The pallet fork 142 is equipped with a body of pallet fork 142d formed in a T-shaped configuration by three pallet beams 143, and a pallet staff 142f; the body of pallet fork 142d is rotatable due to the pallet staff 142f consisting of a shaft.
The pallet jewels 144a, 144b are provided at the distal ends of two pallet beams 143 of the three pallet beams 143; an inter-horn member 145 is mounted to the distal end of the remaining pallet beam 143. The pallet jewels 144a, 144b consist of ruby formed in a rectangular-prism-like configuration; they are glued to the pallet beams 143 by adhesive or the like.
When the pallet fork 142, constructed as described above, rotates around the pallet staff 142f, the pallet jewel 144a or the pallet jewel 144b comes into contact with the distal end of a tooth portion 132a of the escape wheel & pinion 130, more specifically, with the sliding surface 132b thereof. In this process, the pallet beam 143 to which the inter-horn member 145 is mounted comes into contact with a banking pin (not shown), thereby preventing further rotation of the pallet fork 142 in the same direction. As a result, the rotation of the escape wheel & pinion 130 is also temporarily stopped.
Next, a method of manufacturing the escape wheel & pinion 130 described above will be briefly illustrated below.
First, there is prepared a flat aluminum (Al) plate adjusted to a predetermined thickness; then, press molding, cutting by a cutter, wire, laser or the like, etc. are conducted thereon to thereby form the base material 132 having a plurality of tooth portions 132a. Next, the shaft member 131 is driven into the center of the base material 132, and then anodic treatment is performed to thereby cover the entire surface of the base material 132 with the anodic oxide film 133. In this way, the escape wheel & pinion 130 shown in FIGs. 4 and 5 can be produced.
In particular, regarding the manufacturing of the escape wheel & pinion 130, it should be noted that, in addition to being a film of high level of hardness, the anodic oxide film 133 is characterized by low residual stress at the time of coating. Thus, unlike the conventional films, even if increased in thickness, the anodic oxide film 133 does not easily involve generation of a large difference in stress between itself and the base material 132, so that it is little subject to generation of cracks, fissures, etc. Thus, the anodic oxide film 133 can be formed in a thickness of 0.1 µm to ten and several µm (for example 0.1-15 µm or 20 µm or more), thus making it possible to coat the surface of the base material 132 with an anodic oxide film 133 of sufficient thickness, which has been impossible in the prior art. As a result, it is possible to protect the base material 132 with an anodic oxide film 133 of high hardness and sufficient thickness.
Unlike a film simply formed on the base material 132, the anodic oxide film 133 is an oxide formed on the surface of the base material 132 by oxidation reaction through anodic treatment. Thus, the anodic oxide film 133 can exhibit high strength for intimate contact, making it possible to enhance the intimacy with which the base material 132 and the anodic oxide film 133 are held in contact with each other. Thus, if subjected to rubbing, an impact or the like, the anodic oxide film 133 is not easily peeled off from the base material 132.
That is, it is possible to provide an escape wheel & pinion 130 in which the surface of the base material 132 is coated and held in intimate contact with an anodic oxide film 133 of high hardness and sufficient thickness. Thus, it is possible to achieve an enhancement in wear resistance, and to achieve an improvement in terms of durability.
In particular, the number of times that the escape wheel & pinion 130 undergoes sliding exceeds several million a year, which means it is a wheel very subject to wear. However, as stated above, in the escape wheel & pinion 130 of this embodiment, an enhancement in wear resistance is achieved due to the anodic oxide film 133, so that it is not so subject to wear despite the large number of times that it undergoes sliding, which means it is superior in reliability.
Further, in the escape wheel & pinion 130, in which an enhancement in wear resistance is enhanced due to the anodic oxide film 133, there is no need to take general measures for achieving an improvement in wear resistance, such as provision of the distal end of each tooth portion 132a with a step portion (oil sump) for retention of lubricating oil or the like. Thus, it is possible to form the base material 132 in a uniform thickness all over, making it possible to reduce its thickness itself. Thus, it is possible to achieve a reduction in the weight of the escape wheel & pinion 130, and to improve its mobility as a wheel, thereby enhancing its operational efficiency, that is, the escapement efficiency thereof. In particular, in this embodiment, the base material 132 is formed of aluminum (Al), which is a light metal, so that it is especially superior in escapement efficiency.
Further, the mechanical timepiece 1 of this embodiment is equipped with the escapement wheel & pinion 130 as described above, that is, the escapement wheel & pinion 130 which is of high wear resistance, which helps to achieve an improvement in durability, and which helps to achieve an enhancement in escapement efficiency, so that it can tick away the time accurately for a long period of time, thus making it possible to provide a high quality timepiece of high operational reliability.
In the above embodiment, the anodic oxide film 133 may be impregnated with various lubricants. The anodic oxide film 133 formed through anodic treatment is of such a nature as to be of a porous structure, so that when lubricating oil is applied as the lubricant, the lubricating oil can be reliably retained. That is, the anodic oxide film 133 can be sufficiently impregnated with lubricating oil, thus serving as an oil pool. Thus, it is possible to achieve an enhancement in lubrication property, making it possible to achieve a further improvement in terms of wear resistance.
The lubricant is not restricted to lubricating oil; it is also possible to adopt, for example, a granular solid lubricant, such as carbon, teflon (registered trademark), or molybdenum disulfide. In this case, the impregnation is possible by filling the anodic oxide film 133 with the solid lubricant through suction, rubbing or the like. In this case also, the same effect can be attained.
The technical scope of the present invention is not restricted to the above-described embodiment but allows various modifications without departing from the scope of the present invention.
For example, while in the above-described embodiment, the base material 132 is formed of aluminum (Al), it is also possible to employ aluminum alloy, or some other metal material as long as it is a metal allowing anodic treatment.
For example, it is also possible to employ a metal material, such as magnesium (Mg) or magnesium alloy, or titanium (Ti) or titanium alloy, or lithium (Li). In particular, of such metal materials, it is desirable to adopt a metal material that is as light as possible as in the case, for example, of aluminum (Al). This helps to achieve a reduction in weight and, at the same time, to achieve an improvement in the mobility of the product as a wheel, thereby achieving an enhancement in operational efficiency. From this point of view, it is desirable to adopt magnesium (Mg) or magnesium alloy.
While in the above-described example, the timepiece wheel of this embodiment is applied to the escapement wheel & pinion 130, it is applicable not only to the escapement wheel & pinion 130 but also to some other wheel. In particular, it is suitably applicable to a wheel which involves large sliding load and of which high wear resistance is required.
More specifically, as shown in FIGs. 6 and 7, it is applicable to various wheels related to an automatic device (a transmission wheel, a transmission intermediate wheel, etc.). FIG. 6 is a plan view of the front side of the movement of an automatic timepiece. FIG. 7 is a schematic partial sectional view showing a portion extending from a movement barrel to a ball bearing.
As shown in FIGs. 6 and 7, in a movement 200 of an automatic timepiece, a ratchet wheel 201 is rotated through rotation of a winding pinion (not shown), winding up a mainspring (not shown) accommodated in a movement barrel 202. The ratchet wheel 201 is in mesh with a center transmission pinion 205a of a center transmission wheel 205 whose upper and lower shaft portions are pivoted by a barrel bridge 203 and a transmission bridge 204. As a result, through rotation of the ratchet wheel 201, the center transmission wheel 205 is rotated. The center transmission wheel 205 is in mesh with the distal end of a pawl lever 206. The proximal end side of the pawl lever 206 is fixed to a first transmission wheel 209 whose upper and lower shaft portions are pivoted by a center wheel bridge 207 and a transmission wheel bridge 208.
The first transmission wheel 209 is in mesh with a first transmission intermediate wheel 211 whose upper and lower shaft portions are pivoted by a third wheel bridge 210 and the transmission wheel bridge 208. As a result, through rotation of the first transmission wheel, the first transmission intermediate wheel 211 is rotated. Further, the first transmission intermediate wheel 211 is in mesh with a gear 212a formed on the outer peripheral surface of a ball bearing 212. Thus, through rotation of the first transmission intermediate wheel 211, the ball bearing 212 is rotated.
The first transmission wheel 209, the first transmission intermediate wheel 211, and the center transmission wheel 205 are wheels which involve large sliding load and of which high wear resistance is required; and, the timepiece wheel of the present invention is also suitably applicable to these wheels.

Claims

A timepiece wheel (130) comprising:
a base material (132) formed as a wheel of a metal allowing anodic treatment; and

an anodic oxide film (133) formed on the surface of the base material through anodic treatment.
A timepiece wheel according to claim 1, characterized in that the base material is formed in a uniform thickness all over.
A timepiece wheel according to claim 1 or 2, characterized in that the anodic oxide film is impregnated with a lubricant.
A timepiece which is equipped with a timepiece wheel as claimed in one of claims 1 through 3.