Patent Grant
11042124
The present invention relates to a timepiece component constituting a machine component in a timepiece and a method of manufacturing a timepiece component.
In a mechanical timepiece, a speed governor (balance) is conventionally used that is made up of a hairspring and a balance wheel (with a balance staff) and that operates a drive mechanism (movement) while keeping a constant speed with regularity. The balance wheel regularly performs a reciprocating rotary motion according to extension and contraction of a so-called isochronous hairspring keeping a constant speed with regularity. To the balance, an escapement made up of an escape wheel and an anchor is coupled, and energy from the hairspring is transferred to sustain operation (vibration).
In general, a hairspring formed by processing metal is widely known. A hairspring formed by processing metal may not be shaped as designed in some cases due to variations in processing accuracy, effects of internal stress of metal, etc. If the hairspring required to regularly vibrate the balance cannot be formed in a shape as designed, the balance wheel cannot perform the isochronous motion. In this case, deviation in the so-called rate of the timepiece occurs expressed as a certain amount of advance or delay of the timepiece per day.
In recent years, attempts have been made to manufacture a timepiece component by etching processing of a silicon substrate. The timepiece component formed by etching processing of a silicon substrate may be reduced in weight as compared to timepiece components formed by using conventional metal components. Additionally, the timepiece component formed by etching processing of a silicon substrate may be mass-produced with precision. Therefore, small lightweight timepieces are expected to be manufactured by using timepiece components formed by etching processing of a silicon substrate.
A reactive ion etching (RIE) technique is a dry etching technique and may be used for etching a silicon substrate. RIE techniques have advanced in recent years and, among the RIE techniques, a Deep RIE technique has been developed to enable etching with a high aspect ratio. By etching a silicon substrate by using the RIE technique, a mask pattern may be faithfully reproduced in a vertical depth direction without etching going under a portion masked by photoresist, etc., and a timepiece component having a shape as designed may be manufactured accurately.
A timepiece component formed by using silicon has better temperature characteristics than metal and is more resistant to deformation resulting from environmental temperature as compared to a conventional hairspring formed by using metal. Therefore, it is conceivable that a dry etching technique such as the RIE technique may be applied to a timepiece component constituting a speed governing mechanism of a timepiece. On the other hand, since silicon is a brittle material, a timepiece component formed by using silicon may be damaged when subject to a strong impact.
To eliminate such trouble, in a conventional technique, for example, an opening portion is provided in an upper surface of a spring unit forming one flat surface in a planar view of a hairspring so as to reduce the mass of the hairspring, so that the hairspring is minimally affected by impacts while rigidity equivalent to a hairspring without the opening portion is maintained (see, for example, Patent Document 1).
However, the conventional technique described in Patent Document 1 described above has a problem in that since the provision of the opening portion reduces a thickness of a portion of the opening portion, the strength around the opening portion becomes insufficient and may result in damage of the hairspring when the timepiece is subject to a strong impact. In particular, for example, the size of the hairspring varies depending on the size, etc. of the timepiece incorporating the hairspring and, in the case of a typical wristwatch, a hairspring with a diameter of about 5 mm to 8 mm is used.
In a hairspring having such a diameter, the width of the upper surface of the portion constituting the spring unit is several dozen μm, and the conventional technique described in the patent document 1 described above has a problem in that since the opening portion is provided in such a thin portion, the spring unit is more susceptible to damage. Such a hairspring is damaged, for example, when the timepiece is subject to a strong force, resulting in contact between adjacent coil-shaped spring units.
Additionally, when some kind of impact is applied to a hairspring formed by using a brittle material such as silicon, stress concentrates at a corner of the hairspring. Therefore, when the timepiece is subject to a strong impact, the corner of the hairspring chips or cracks due to the force. If the hairspring is damaged or a portion thereof is chipped, the balance wheel cannot perform a regular reciprocating rotary motion and becomes unable to function as a timepiece. Moreover, a broken piece of the damaged hairspring entering a drive mechanism causes a problem in that a fatal failure may occur in the timepiece itself.
To solve the problems of the conventional technique described above, it is an object of the present invention to provide a timepiece component and a method of manufacturing a timepiece component that is highly accurate in terms of manufacturing, that enables a weight reduction, and that is resistant to breaking and capable of exhibiting high strength even when a strong external impact is applied.
To solve the problems above and achieve an object, according to the present invention, a timepiece component constituting a timepiece, includes a base material formed using a nonconductive first material as a main component; an intermediate film provided on at least a portion of a surface of the base material; and a buffer film stacked on the intermediate film and mainly composed of a second material having a tenacity higher than that of the first material.
In the timepiece component, the first material is silicon.
In the timepiece component, the second material is a resin.
In the timepiece component, the base material includes a stepped portion on an outer surface, and the intermediate film is provided at a position covering at least the stepped portion.
In the timepiece component, the timepiece component is a hairspring constituting a speed governing mechanism of a driving unit of a mechanical timepiece.
In the timepiece component, the timepiece component is one of a gear, an anchor, and a balance wheel constituting a driving unit of a timepiece and having a hole into which another member is fitted.
According to another aspect of the present invention, a method of manufacturing a timepiece component, includes forming a base material into a shape of a timepiece component by etching a substrate formed using a nonconductive first material as a main component; forming an intermediate film on at least a portion of a surface of the base material; and forming a buffer film by stacking on the intermediate film, a material mainly composed of a second material having a tenacity higher than that of the first material.
The method further includes forming a stepped portion on the surface of the base material, where the forming of the intermediate film is performed after the forming of the stepped portion.
In the method, the forming of the buffer film includes forming the buffer film by applying a predetermined voltage to the intermediate film after the base material having the intermediate film formed thereon is immersed in a predetermined electrodeposition liquid.
The timepiece component and the method of manufacturing a timepiece component according to the present invention provides an effect of being highly accurate in terms of manufacturing while enabling a weight reduction and resistance to breaking, and exhibiting high strength even when an external force is applied.
Embodiments of a timepiece component and a method of manufacturing a timepiece component according to the present invention will be described in detail with reference to the accompanying drawings.
(Drive Mechanism of Mechanical Timepiece)
First, a drive mechanism of a mechanical timepiece will be described as a drive mechanism of a timepiece incorporating a timepiece component of a first embodiment according to the present invention manufactured by a manufacturing method of the first embodiment according to the present invention.
In
The power mainspring is an elongated thin metal sheet in a wound state and is housed in the barrel 102. An end portion at the center of the power mainspring (an end portion located on the inner circumferential side in the wound state) is attached to a center axis (barrel arbor) of the barrel 102. An outer end portion (an end portion located on the outer circumferential side in the wound state) of the power mainspring is attached to an inner surface of the barrel 102.
The escapement 103 is made up of an escape wheel 106 and an anchor 107. The escape wheel 106 is a gear including key-shaped teeth, and the teeth of the escape wheel 106 mesh with the anchor 107. The anchor 107 converts the rotary motion of the escape wheel 106 into reciprocating motion by meshing with the teeth of the escape wheel 106.
The balance 104 is made up of a hairspring 108, a balance wheel 109, etc. The hairspring 108 and the balance wheel 109 are coupled by a balance staff 109a provided at the center of the balance wheel 109. The hairspring 108 is an elongated member in a wound state and has a spiral shape (see
The balance 104 may regularly reciprocate according to expansion and contraction due to a spring force of the hairspring 108. The balance wheel 109 forms a ring shape and adjusts/controls the repetitive motion from the anchor 107 to keep vibration at a constant speed. The balance wheel 109 is provided with arms extending radially from the balance staff 109a inside the ring shape formed by the balance wheel 109.
The train wheel 105 is provided between the barrel 102 and the escape wheel 106 and is made up of multiple gears meshing with each other. For example, the train wheel 105 is made up of a center wheel and pinion 110, a third wheel and pinion 111, a fourth wheel and pinion 112, etc. The barrel wheel of the barrel 102 meshes with the center wheel and pinion 110. A second hand 113 is mounted on the fourth wheel and pinion 112, and a minute hand 114 is mounted on the center wheel and pinion 110. In
In the drive mechanism 101, the center of the power mainspring is fixed to the center (barrel arbor) of the barrel 102 so as not to rotate backward and the outer end portion of the power mainspring is fixed to the inner circumferential surface of the barrel, so that when the power mainspring wound around the center (barrel arbor) of the barrel 102 attempts to return to an original state, the barrel 102 is urged by the outer end portion of the power mainspring attempting to loosen in the same direction as the wound-up direction and rotates in the same direction as the loosening direction of the wound-up mainspring. The rotation of the barrel 102 is sequentially transmitted through the center wheel and pinion 110, the third wheel and pinion 111, and the fourth wheel and pinion 112 and is transmitted from the fourth wheel and pinion 112 to the escape wheel 106.
Since the escape wheel 106 is meshed with the anchor 107, when the escape wheel 106 rotates, a tooth (impact surface) of the escape wheel 106 pushes up an entry pallet of the anchor 107 and, as a result, the balance 104 is rotated by a tip of the anchor 107 on the balance 104 side. When the balance 104 rotates, an exit pallet of the anchor 107 immediately stops the escape wheel 106. When the balance 104 rotates backward due to the force of the hairspring 108, the entry pallet of the anchor 107 is released and the escape wheel 106 rotates again.
In this way, the speed governing mechanism 104 causes the balance 104 to repeat the regular reciprocating rotary motion according to the expansion and contraction of the isochronous hairspring 108, and the escapement 103 continuously gives the force for reciprocation to the balance 104 and rotates the gears in the train wheel 105 at constant speed according to the regular vibrations from the balance 104. The escape wheel 106, the anchor 107, and the balance 104 constitute a speed governing mechanism converting the reciprocating motion of the balance 104 into the rotary motion.
(Structure of Hairspring 108)
In
In the spring arm 201, the spring arm 201a is located at the innermost circumferential side of the spring unit 2 with the spring arm 201b and spring arm 201c located in order from the inner circumferential side toward the outer circumferential side, and the spring arm 201d is located on the outermost circumferential side of the spring unit 2. Each of the spring arms 201a to 201d may be 50 μm in width and 100 μm in height, for example.
The spring arms 201a to 201d are made up of intermediate films 51a, 51b, 51c, 51d and buffer films 21a, 21b, 21c, 21d sequentially stacked on surfaces of base materials 11a, 11b, 11c, 11d. The buffer films 21a to 21d are formed on the outermost surface of the hairspring 108a. As described above, the spring arms 201a to 201d form a single integrated structure, and the base materials 11a to 11d therefore form a single structure as well. Similarly, the intermediate films 51a to 51d also form a single structure, and the buffer films 21a to 21d form a single structure as well.
The base materials 11a to 11d are formed by using a first material. For the first material, for example, a material mainly composed of quartz, ceramics, silicon, silicon oxide, etc. may be used. By using silicon as the first material for forming the base materials 11a to 11d, the hairspring 108a may be reduced in weight.
Additionally, by using silicon as the first material 11 for forming the base materials 11a to 11d, favorable processability may be ensured in manufacturing of the hairspring 108a. For example, by using silicon as the first material 11 for forming the base materials 11, the hairspring 108a may be manufactured by using a Deep RIE technique.
The Deep RIE technique is generally frequently used as a semiconductor manufacturing technique. The Deep RIE technique is a kind of reactive ion etching that is a kind of dry etching processing, and is widely known as a technique capable of microfabrication with high precision. By processing a silicon substrate through dry etching using the Deep RIE technique, the hairspring 108a may be manufactured with high precision. By manufacturing the hairspring 108a by using the Deep RIE technique, the spring unit 2, the collet 3, and the stud 4 may integrally be formed.
The intermediate films 51a to 51d are formed by using a material having a tenacity higher than that of the first material forming the base materials 11a to 11d. The tenacity indicates a property of being hard to break against an external pressure, or so-called “toughness”. Materials having high tenacity exhibit favorable toughness. For example, the intermediate films 51a to 51d may be formed by using, for example, silicon oxide (SiO2), alumina (aluminum oxide: Al2O3), or DLC (Diamond-Like Carbon).
The intermediate films 51a to 51d formed of silicon oxide include a natural oxide film formed of silicon oxide formed by exposing silicon to the atmosphere. DLC is mainly composed of carbon (C) isotopes and hydrocarbons and forms an amorphous structure. DLC is a hard film and includes those having a conductivity imparted thereto by various methods such as implanting plasma ions and adding metal elements by sputtering in recent years.
The intermediate films 51a to 51d may have a conductivity and may be formed by using a metal material such as copper (Cu), gold (Au), nickel (Ni), and titanium (Ti), for example. In particular, the intermediate films 51a to 51d may be formed by using an alloy acquired by mixing multiple materials.
For example, the intermediate films 51a to 51d may be formed, for example, by forming films of copper (Cu) with a thickness of 0.2 μm on the surfaces of the base materials 11a to 11d. Alternatively, for example, the intermediate films 51a to 51d may be achieved as natural oxide films formed by exposing silicon forming the base materials 11a to 11d to the atmosphere.
The material forming the intermediate films 51a to 51d may be set appropriately depending on the hardness required for the timepiece component such as the hairspring 108a, for example. The hardness required for the timepiece component such as the hairspring 108a may be set arbitrarily depending on the specifications, the usage environment, the cost of manufacturing of the mechanical timepiece, for example. The hardness required for the timepiece component such as the hairspring 108a may be adjusted by not only the material of the intermediate films 51a to 51d but also the film thickness of the intermediate films 51a to 51d, for example.
For example, when a high hardness is required for the timepiece component such as the hairspring 108a, titanium (Ti) may be used that is a metal harder than copper (Cu) and gold (Au). On the other hand, for example, when flexibility and ductility are required for the clock component such as the hairspring 108a, copper (Cu) or gold (Au) having relatively soft characteristics can be used. Copper (Cu) and gold (Au) may exhibit ductility because of soft characteristics and may therefore deform following the deformation of the hairspring 108a, so that even when silicon is used for forming the hairspring 108a, the fragility (brittleness) of the hairspring 108a may be reduced.
The buffer films 21a to 21d are mainly composed of a second material. The second material may be achieved by a material having a tenacity higher than that of the first material. For example, if the first material is silicon, the second material may be achieved by a resin having a tenacity higher than that of silicon. Materials usable as the second material include, for example, an acrylic resin, an epoxy resin, and a para-xylylene-based polymer that is a polymer synthetic material.
Various improvements have been made in acrylic resins in recent years, resulting in the development of an acrylic resin called electrodeposition resist that may be formed in to a film having a constant thickness by an electrodeposition method and that may be patterned. By using such an electrodeposition resist made of an acrylic resin, the buffer films 21a to 21d having a constant (uniform) film thickness may be provided on a surface of a timepiece component having a precise and complicated shape such as the hairspring 108a.
The hairspring 108a required to extend and contract in a constant cycle becomes unbalanced and eccentric if the thickness of the buffer films 21a to 21d provided on the surface of the hairspring 108a is not uniform. By using the acrylic resin called electrodeposition resist, the buffer films 21a to 21d having a constant (uniform) film thickness may be provided, so that the hairspring 108a may operate correctly. As described above, the electrodeposition resist made of an acrylic resin is suitable for a material of timepiece components having a precise and complicated shape, or particularly, the buffer films 21a to 21d etc. used for the hairspring 108a extending and contracting for operation.
Additionally, in not only the hairspring 108a but also other timepiece components, if a portion with uneven thickness such as a so-called “buffer film gathering” exists on the surfaces of the buffer films 21a to 21d or the buffer films 21a to 21d differs in film thickness depending on a location, a trouble may occur such as rubbing against another structure at the time of movement and generating inconsistency in operation, for example. If the buffer films 21a to 21d protrude from the surfaces of the base materials 11a to 11d, the outer shape of the timepiece component may become different from designed dimensions. In such a case, the shape is not formed as designed, resulting in a timepiece component lacking a predetermined performance (a defective product).
In this regard, by using the acrylic resin called electrodeposition resist as the second material to form the buffer films 21a to 21d with the electrodeposition method, the buffer films 21a to 21d having a constant (uniform) film thickness can be formed on the surfaces of the base materials 11a to 11d, so that the trouble as described can be avoided. The buffer films 21a to 21d are formed to be 5 μm in thickness, for example.
When the buffer films 21a to 21d are formed with the electrodeposition method, the intermediate films 51a to 51d can be used as electrodes to which a voltage is applied during electrodeposition. In the electrodeposition of an object by the electrodeposition method, a material to be electrodeposited (e.g., an acrylic resin) is formed on an upper portion (surface) of an underlying electrode. Therefore, by providing the intermediate films 51a to 51d having shapes matched to the shapes of the buffer films 21a to 21d desired to be formed, the buffer films 21a to 21d reflecting the shapes of the underlying intermediate films 51a to 51d may easily be formed.
(Method of Manufacturing Hairspring 108a)
A method of manufacturing the hairspring 108a will be described as a method of manufacturing a timepiece component of the first embodiment according to the present invention.
For manufacturing the hairspring 108a, first, a silicon substrate 60 is prepared. The silicon substrate 60 has an area and a thickness sized such that at least the hairspring 108a may be taken out. Considering the productivity of the hairspring, the silicon substrate 60 is preferably sized such that a number of the hairsprings 108a can be taken out.
Subsequently, as depicted in
Subsequently, as depicted in
Subsequently, as depicted in
The silicon substrate 60 can be processed into a shape of an hairspring having a predetermined width by performing dry etching through the mask layer 91a. The silicon substrate 60 may be processed to a predetermined height (depth) by managing the processing time of the dry etching. By the dry etching through the mask layer 91a to the silicon substrate 60, the base materials 11a to 11d serving as the spring arms 201a to 201d are formed as denoted by reference characters 11a to 11d in
Subsequently, as depicted in
Subsequently, as depicted in
The intermediate films 51a to 51d using copper (Cu), gold (Au), nickel (Ni), etc. are formed, for example, by using a sputtering method that is a kind of a vacuum film formation method to be 0.2 μm in thickness, for example. Alternatively, the intermediate films 51a to 51d may be achieved by natural oxide films (silicon oxide) formed on the surface of the silicon substrate 60 by exposing the silicon substrate 60 to the atmosphere, for example.
The intermediate films 51a to 51d serve as a foundation when the buffer films 21a to 21d are provided at the subsequent step. Additionally, the intermediate films 51a to 51d using copper (Cu), gold (Au), nickel (Ni), etc. act as electrodes when the buffer films 21a to 21d are formed by using an electrodeposition method described later. In the case of causing the buffer films 21a to 21d to act as electrodes, preferably, the intermediate films 51a to 51d are formed by using a material having a low electrical resistance.
Subsequently, as depicted in
The second material forming the buffer films 21a to 21d may be selected depending on the hardness required for a timepiece component such as the hairspring 108a and the material forming the intermediate films 51a to 51d. In other words, the material forming the intermediate films 51a to 51d may be selected depending on the second material forming the buffer films 21a to 21d.
For example, when the intermediate films 51a to 51d are formed by using copper (Cu), the second material constituting the buffer films 21a to 21d may b be preferably achieved by using an acrylic resin or an epoxy resin. The buffer films 21a to 21d may be formed easily by using various known techniques such as a technique of spraying an acrylic resin or an epoxy resin (e.g., sputtering) or dropping a liquefied resin (e.g., spin coating) onto the silicon substrate 60 in a state of being rotated by a spin coating apparatus, for example, and a technique of immersing the substrate in a liquid tank containing a liquefied resin and then removing the substrate to form the films.
For example, in the case of forming the buffering films 21a to 21d by using a technique of dropping a liquefied resin for forming the films, first, a dispenser (not depicted) filled with a predetermined liquefied resin is prepared. Subsequently, for example, while a movable table (not depicted) with the hairspring 108a placed thereon is moved in a predetermined direction, the resin of the buffer films 21a to 21d is dropped from this dispenser. In this case, the resin is dropped so as not to protrude from the intermediate films 51a to 51d on the surfaces of the spring arms 201a to 201d.
Subsequently, a predetermined curing treatment is performed to cure the resin. The curing treatment curing the resin may be achieved by, for example, radiating ultraviolet light for a predetermined time in the case of using an ultraviolet curable resin. Alternatively, the curing treatment may be achieved by, for example, heating for a predetermined time in the case of using a thermosetting resin. As a result, the buffer films 21a to 21d may be formed on the surfaces of the intermediate films 51a to 51d formed on the surfaces of the spring arms 201a to 201d.
The buffer films 21a to 21d may also be formed by using an electrodeposition method. In the technique of dropping the resin for forming the buffer films 21a to 21d, the resin may not be formed uniformly in rare cases. In contrast, by using the electrodeposition method, the resin constituting the buffer films 21a to 21d may be formed into films having a constant thickness, and may be patterned easily, on the surfaces of the intermediate films 51a to 51d. When the buffer films 21a to 21d are formed by the electrodeposition method, an acrylic resin called electrodeposition resist is used. The electrodeposition method is a widely known film formation method in which a substance precipitated by electrolysis is attached for film formation onto the intermediate films 51a to 51d to which a voltage is applied.
For example, when the buffer films 21a to 21d are formed by using the electrodeposition method, the intermediate films 51a to 51d are formed in advance on a predetermined portion of the hairspring 108a. When the buffer films 21a to 21d are formed by using the electrodeposition method, preferably, the intermediate films 51a to 51d are formed by using copper (Cu) having a low electrical resistance, for example. A terminal region (not depicted) electrically connected to the intermediate films 51a to 51d is formed at the same time as the formation of the intermediate films 51a to 51d. This terminal region is provided in a portion not affecting the shape of the hairspring 108a.
Subsequently, the silicon substrate 60 with the intermediate films 51a to 51d and the terminal region formed is immersed in a state of being fixed by a known holding device into a liquid tank filled with an electrodeposition liquid containing the electrodeposition resist. In this case, a probe, etc. are preliminarily brought into contact with the terminal region electrically connected to the intermediate films 51a to 51d. The probe, etc. are connected to a predetermined power supply unit so that a predetermined voltage may be applied to the intermediate films 51a to 51d.
When a predetermined voltage is applied to the intermediate films 51a to 51d immersed in the electrodeposition liquid tank with the probe, etc. brought into contact with the terminal region, the electrodeposition resist precipitated by electrolysis in the liquid tank is attached to the surfaces of the intermediate films 51a to 51d. The voltage is applied until the electrodeposition resist reaches a predetermined film thickness. Although not particularly limited hereto, the electrodeposition resist is formed into a film having a thickness of 5 μm. The film thickness of the electrodeposition resist may be freely set in view of specifications, etc. of the mechanical timepiece. Therefore, when the buffer films 21a to 21d are formed by using the electrodeposition method, the film thickness of the electrodeposition resist may be adjusted easily by managing the time of application of the voltage.
Subsequently, the application of the voltage is terminated and the silicon substrate 60 is taken out from the liquid tank. As a result, the buffer films 21a to 21d reflecting the shapes of the intermediate films 51a to 51d may be formed on the surfaces of the intermediate films 51a to 51d to have a constant film thickness. By using the electrodeposition method, the buffer films 21a to 21d may be formed without significantly varying the shape of the hairspring 108a before and after forming the buffer films 21a to 21d.
For example, when the intermediate films 51a to 51d are achieved by natural oxide films (silicon oxide), the second material constituting the buffer films 21a to 21d may be preferably achieved by a resin material such as a para-xylylene-based polymer. The para-xylylene-based polymer is a polymer of an organic compound, para-xylylene, and can be formed into a thin film shape by causing a polymerization reaction on the surface of the hairspring 108a.
The para-xylylene-based polymer has a high conformal coatability. Therefore, by using the para-xylylene-based polymer, the buffer films 21a to 21d having a uniform film thickness without a pinhole may be formed even when a component has a fine complicated shape due to groove/hole/edge portions as in the case of a timepiece component such as the hairspring 108a used in a wristwatch, for example. The buffer films 21a to 21d made of the para-xylylene-based polymer may be formed by using a gas phase vapor deposition polymerization method that is a kind of chemical vapor deposition (CVD), for example.
With the manufacturing method as described above, the hairspring 108a with the buffer films 21a to 21d formed on the entire surface may be manufactured. In the hairspring 108a that is the timepiece component of the first embodiment, the base materials 11a to 11d are main members forming the shape of the timepiece component and are made of the first material (e.g., silicon) that is a nonconductive material, and the intermediate films 51a to 51d are included at least partially on the surfaces of the base materials 11a to 11d. The buffer films 21a to 21d made of the second material having a tenacity higher than that of the first material are provided on the surfaces of the intermediate films 51a to 51d.
As described above, the timepiece component of the first embodiment includes the base materials 11a to 11d formed by using silicon. Therefore, microfabrication may be performed with high accuracy by etching processing using the Deep RIE technique, so that a timepiece component forming a fine complicated shape may be manufactured with high precision and reduced variations in processing accuracy.
Moreover, the timepiece component of the first embodiment includes at least partially on the surfaces of the base materials 11a to 11d the intermediate films 51a to 51d formed by using a material having a tenacity higher than that of silicon forming the base materials 11a to 11d. Therefore, the timepiece component of the first embodiment may reduce the fragility of silicon to achieve a robust timepiece component even when silicon is used for forming the base materials 11a to 11d.
Furthermore, the timepiece component of the first embodiment includes the buffer films 21a to 21d having a high tenacity on the surfaces of the intermediate films 51a to 51d. Therefore, the timepiece component of the first embodiment has the buffer films 21a to 21d acting as a cushion and may mitigate the impact with the buffer films 21a to 21d even when the timepiece component comes into contact with another structure. Additionally, inclusion of the buffer films 21a to 21d enables the timepiece component of the first embodiment to prevent cracking and chipping due to stress concentration at a corner, etc. Therefore, the durability of the timepiece component may be improved.
As described above, the timepiece component of the first embodiment may reduce the fragility of silicon with the intermediate films 51a to 51d provided at least partially on the surfaces of the base materials 11a to 11d formed by using a silicon material and may mitigate external forces applied to the timepiece component by the buffer films 21a to 21d having a high tenacity provided on the surfaces of the intermediate films 51a to 51d so as to prevent cracking or chipping due to stress concentration at corners, etc.
According to the timepiece component of the first embodiment, since two different types of films are included as the intermediate films 51a to 51d and the buffer films 21a to 21d, a timepiece component may be achieved that is robust and resistant to breakage even when a contact with another structure or stress concentration occurs due to an impact.
According to the timepiece component of the first embodiment 1, the intermediate films 51a to 51d may be formed by using a material having a conductivity such as a metal material so as to use the intermediate films 51a to 51d as electrodes. In this case, the buffer films 21a to 21d may be formed by using the electrodeposition method, and the use of the electrodeposition method enables the formation of the buffer films 21a to 21d having a constant film thickness and a high coatability to the foundation (e.g., the intermediate films 51a to 51d).
According to the timepiece component of the first embodiment, even when a metal material is used, the metal material is used as a material forming the intermediate films 51a to 51d covering the surfaces of the base materials 11a to 11d. Therefore, the film thickness of the intermediate films 51a to 51d is extremely thin with respect to the thickness of the silicon. As a result, the timepiece component of the first embodiment does not adversely affect the excellent temperature characteristics of silicon.
Thus, even when the intermediate films 51a to 51d are formed by using a metal material having inferior temperature characteristics for the timepiece component as compared to the silicon forming the base materials 11a to 11d, the temperature characteristics of the first material such as silicon is not adversely affected unlike a metal plate formed by rolling, etc. of metal having a predetermined plate shape. As a result, the timepiece component of the first embodiment may exert the excellent temperature characteristics of silicon and may exhibit high strength.
As described above, according to the timepiece component of the first embodiment, the hairspring 108a highly accurate in terms of manufacturing may be reduced in weight by using the first material mainly composed of silicon, etc. for forming the base materials 11a to 11d and since the intermediate films 51a to 51d and the buffer films 21a to 21d are provided, the timepiece component is resistant to breakage and may exhibit high strength even when an external impact is applied.
A hairspring will be described as a timepiece component of a second embodiment according to the present invention manufactured by a manufacturing method of the second embodiment according to the present invention. In the second embodiment, portions identical to as those of the first embodiment described above are denoted by the same reference characters used in the first embodiment and will not be described. In the description of the second embodiment, the hairspring 108 will be denoted by reference character 108b.
The spring arms 202a to 202d may be, for example, 50 μm in width and 100 μm in height as is the case in the first embodiment. Both end portions of the spring unit 2 are formed by overlapping intermediate films 52a, 52b, 52c, 52d and buffer films 22a, 22b, 22c, 22d as is the case in the first embodiment. In the spring arms 202a to 202d, for example, the base materials 11a to 11d may be formed by using silicon as is the case in the first embodiment.
In the spring arms 202a to 202d, the intermediate films 52a to 52d are provided to cover four corners 1100 of the base materials 11a to 11d made of the first material. The intermediate films 52a to 52d can be formed by using the same material as the first embodiment in the same way as the manufacturing method of the first embodiment. For example, as is the case in the first embodiment, the film thickness of the intermediate films 52a to 52d can be 0.2 μm.
In the spring arms 202a to 202d, the buffer films 22a to 22d are provided as upper layers on the intermediate films 52a to 52d. The buffer films 22a to 22d are formed by using the second material as a main component. Although not particularly limited hereto, the film thickness of the buffer films 22a to 22d may be 5 μm, for example. The second material may be achieved by, for example, a resin or an electrodeposition resist as is the case in the first embodiment. If the electrodeposition resist is used as the second material, the buffer films 22a to 22d having a constant film thickness may be formed on the surfaces of the intermediate films 52a to 52d as is the case in the first embodiment.
The electrodeposition resist is the same as the photoresist and, therefore, by combining known photolithography and etching techniques, the buffer films 22a to 22d patterned in a predetermined shape may be formed only at the four corners 1100 of the base materials 11a to 11d in the spring arms 202a to 202d.
If some impact is applied to the hairspring 108b, the stress concentrates at the corners 1100. Therefore, when the hairspring 108b is formed by using a brittle material such as silicon, the corners 1100 may possibly chip or crack due to the effects of the impact. In this regard, as depicted in
(Method of Manufacturing Hairspring 108b)
A method of manufacturing the hairspring 108b will be described as a method of manufacturing a timepiece component of the second embodiment according to the present invention.
The buffer films 22a to 22d are patterned into a predetermined shape. As depicted in
The buffer films 22a to 22d of the second embodiment may be formed by using, for example, the electrodeposition resist made of a photosensitive material of a type in which an exposed portion is developed and dissolved. In this case, the exposure masks 500, 510 used are designed such that a portion to be left as a pattern is not exposed. For example, if it is desired to leave buffer films on the corners 1100 of the hairspring 108b, the exposure masks 500, 510 are shaped such that the ultraviolet light 600 is not applied to the corners 1100.
In patterning the buffer films 22a to 22d, as depicted in
Subsequently, the exposed portions of the buffer films 21a to 21d made of the electrodeposition resist are removed as depicted in
Subsequently, the intermediate films 51a to 51d are etched by using, as a mask, the buffer films 22a to 22d patterned only on the corners 1100 of the hairspring 108b. For example, if the intermediate films 51a to 51d are formed by using copper (Cu), the intermediate films 51a to 51d may be etched by using a cupric chloride-based etchant.
As a result, as depicted in
As described above, in the timepiece component of the second embodiment, by forming the buffer films 21a to 21d from the electrodeposition resist in advance, the buffer films 21a to 21d may be processed easily by combining well-known photolithography and etching techniques using a conventional photoresist. As a result, the buffer films 22a to 22d covering only the four corners 1100 of the base materials 11a to 11d may easily be formed.
In the manufacturing method of the second embodiment, the subsequent processing may be eliminated in the state depicted in
A hairspring will be described as a drive mechanism of a timepiece incorporating a timepiece component of a third embodiment according to the present invention manufactured by a manufacturing method according to the third embodiment according to the present invention. In the third embodiment, portions identical to those of the first and second embodiments described above are denoted by the same reference characters used in the first and second embodiments and will not be described. In the description of the third embodiment, the hairspring 108 will be denoted by reference character 108c.
In the spring unit 2, end surfaces (flat surfaces) 81 on the front surface side of the base materials 11a to 11d are provided with groove portions 71a, 71b, 71c, 71d recessed in center portions in the width direction from the flat surfaces 81 toward end surfaces (flat surfaces) 82 on the back side of the base materials 11a to 11d. The groove portions 71a to 71d are recesses having a predetermined width and a predetermined depth. As a result, stepped portions are formed by the flat surfaces 81 and the groove portions 71a to 71d on the front surface side of the base materials 11a to 11d.
Additionally, in the spring unit 2, the flat surfaces 82 of the base materials 11a to 11d are provided with groove portions 72a, 72b, 72c, 72d recessed in center portions in the width direction from the flat surfaces 82 toward the flat surfaces 81. The groove portions 72a to 72d are recesses having a predetermined width and a predetermined depth. As a result, stepped portions are formed by the flat surfaces 82 and the groove portions 72a to 72d on the back surface side of the base materials 11a to 11d.
The groove portions 71a to 71d and the groove portions 72a to 72d are formed to have dimensions of 20 μm in width and 40 μm in depth. The dimensions of the groove portions 71a to 71d and the groove portions 72a to 72d are not particularly limited. Intermediate films 53a, 53b, 53c, 53d are provided on the inner sides (inner surfaces) of the groove portions 71a to 71d and the groove portions 72a to 72d.
As is the case in the first and second embodiments, the intermediate films 53a to 53d are formed by using a material having a tenacity higher than that of the first material forming the base materials 11a to 11d. The intermediate films 53a to 53d may be formed by using, for example, silicon oxide, alumina, DLC, a metal material, or an alloy acquired by mixing a metal material and other materials. As is the case in the first and second embodiments, the intermediate films 53a to 53d may be formed to be 0.2 μm in thickness, for example.
Buffer films 23a to 23d are provided on the surfaces of the intermediate films 53a to 53d as upper layers on the intermediate films 53a to 53d. The buffer films 23a to 23d are provided to fill the groove portions 71a to 71d and the groove portions 72a to 72d. The buffer films 23a to 23d are formed by using the second material having a tenacity higher than that of the first material, for example, as is the case in the first and second embodiments described above. For example, a resin, an electrodeposition resist, etc. may be used as the second material for the buffer films 23. By using the electrodeposition resist, the buffer films 23a to 23d having a constant film thickness (e.g., 5 μm) may be formed as the upper layers on the intermediate films 53a to 53d. In the third embodiment, the buffer films 23a to 23d are provided to fill the groove portions 71a to 71d and the groove portions 72a to 72d as depicted in
Resin generally has a density lower than silicon. Therefore, by providing the groove portions 71a to 71d and the groove portions 72a to 72d in the base materials 11a to 11d formed of silicon and by filling the groove portions 71a to 71d and the groove portions 72a to 72d with the buffer films 23 formed of a resin as in the case of the hairspring 108c, the hairspring 108c may be reduced in weight by the volume of the groove portions 71a to 71d and the groove portions 72a to 72d.
Furthermore, by covering the inside of the groove portions 71a to 71d and the groove portions 72a to 72d with the intermediate films 53a to 53d formed by using a metal material, the hairspring 108c may be compensated for decreased strength due to provision of the groove portions 71a to 71d and the groove portions 72a to 72d (removal of volumes corresponding to the groove portions 71a to 71d and the groove portions 72a to 72d from the base materials 11a to 11d), and the strength of the hairspring 108c may be improved.
Moreover, by providing the buffer films 23 having a high tenacity as the upper layers on the intermediate films 53a to 53d, the hairspring 108c becomes resistant to destruction, and the durability of the hairspring 108c may be improved. Additionally, since the intermediate films 53a to 53d are provided to cover the corners of the groove portions 71a to 71d and the groove portions 72a to 72d, even when the hairspring 108c is subject to a strong impact, the corners may be prevented from being damaged due to stress concentration. As a result, the robust hairspring 108c may be manufactured.
By providing the buffer films 23 inside the groove portions 71a to 71d and the groove portions 72a to 72d, the resin may be provided inside the base materials 11a to 11d and as a result, the spring unit 2 may be given an elastic quality so that the spring unit 2 may be made resistant to breakage.
In the third embodiment described above, the groove portions 71a to 71d and the groove portions 72a to 72d are formed by making concave-shaped recesses in the flat surfaces 81, 82 so as to constitute the stepped portions; however, the stepped portions are not limited to those formed of a concave shape. For example, the flat surfaces 81, 82 may be projected in a convex shape in the direction opposite to the groove portions 71a to 71d and the groove portions 72a to 72d to constitute protrusions, and the intermediate films 53a to 53d and the buffer films 23 may be formed to cover the protrusions. As a result, the robust hairspring 108c may be manufactured.
In the description of the third embodiment, the hairspring 108c is provided with the groove portions 71a to 71d and the groove portions 72a to 72d in both the flat surface 81 and the flat surface 82; however, this is not a limitation. The groove portions 71a to 71d and the groove portions 72a to 72d may be provided in only one of the flat surface 81 and the flat surface 82.
(Method of Manufacturing Hairspring 108c)
A method of manufacturing the hairspring 108c will be described as a method of manufacturing the timepiece component of the third embodiment according to the present invention.
Subsequently, as depicted in
The mask layers 92a, 92b function as protective films in processing using the Deep RIE technique performed at the subsequent step. The mask layers 92a, 92b may be preferably formed of silicon oxide (SiO2) having an etching rate slower than silicon. The mask layers 92a, 92b may be formed by growing silicon oxide to a film thickness of 1 μm, for example.
Subsequently, as depicted in
In other words, a silicon substrate 62 is formed that has the groove portions 71a to 71d formed on the flat surface 81 side and the groove portions 72a to 72d formed on the flat surface 82 side. Although not particularly limited hereto, the groove portions 71a to 71d and the groove portions 72a to 72d are formed to be 20 μm in width and 40 μm in depth, for example. When the silicon substrate 61 is dry-etched by the Deep RIE technique, the etching may be performed twice, separately on respective surfaces as the dry etching performed on the flat surface 81 side and the dry etching performed on the flat surface 82 side.
Subsequently, as depicted in
Subsequently, as depicted in
The mask layers 93a, 93b function as protective films in processing using the Deep RIE technique performed at the subsequent step. The mask layers 93a, 93b may be preferably formed of silicon oxide (SiO2) having an etching rate slower than that of silicon. The mask layers 93a, 93b may be formed by growing silicon oxide to a film thickness of 1 μm, for example.
Subsequently, as depicted in
Subsequently, as depicted in
Subsequently, as depicted in
Subsequently, as depicted in
Subsequently, as depicted in
For a material having a high tenacity and capable of being patterned (easy to process), for example, an electrodeposition resist made of an acrylic resin used in an electrodeposition method is preferable. Use of the electrodeposition resist made of an acrylic resin enables the buffer films 25a to 25d having a constant thickness to be formed and the buffer films 25a to 25d may be favorably patterned.
Use of such an electrodeposition resist made of an acrylic resin as the buffer films 25a to 25d, as depicted in
Subsequently, as depicted in
For patterning the buffer films 25a to 25d, as depicted in
Subsequently, the exposed portions of the buffer films 25a to 25d made of the electrodeposition resist are removed as depicted in
Subsequently, the intermediate films 55a to 55d are etched by using, as a mask, the buffer films 23a to 23d formed in the groove portions 71a to 71d and the groove portions 72a to 72d of the hairspring 108c. For example, if the intermediate films 55a to 55d are formed by using copper (Cu), the intermediate films 55a to 55d may be etched by using a cupric chloride-based etchant.
As a result, as depicted in
In the manufacturing method of the third embodiment, the subsequent processing may be eliminated in the state depicted in
As depicted in
Although the third manufacturing method described above has been described as the manufacturing method in which the buffer films 23a to 23d are formed in the groove portions 71a to 71d and the groove portions 72a to 72d having the concave shape as the stepped portions, even stepped portions having a convex shape (not depicted) may be manufactured by the same manufacturing method. In particular, when the stepped portions are formed, a mask may be patterned to form protrusions on the flat surfaces 81, 82. Portions to be masked and portions to be etched in this case will not be described in detail since this is widely used in the processing of semiconductor devices.
(Method of Manufacturing Hairspring)
A method of manufacturing a hairspring of a fourth embodiment according to the present invention will be described as a method of manufacturing a timepiece component of the fourth embodiment according to the present invention. In the fourth embodiment, portions identical to those of the first to third embodiments described above are denoted by the same reference characters used in the first to third embodiments and will not be described. In the fourth embodiment, a method of manufacturing the hairspring 108 (108d) will be described.
Subsequently, as depicted in
As depicted in
The first mask layers 95a, 95b function as protective films in processing using the Deep RIE technique performed at the subsequent step. The first mask layers 95a, 95b are preferably formed of silicon oxide (SiO2) having an etching rate slower than silicon. The first mask layers 95a, 95b may be formed by growing silicon oxide to a film thickness of 1 μm, for example.
The second mask layers 97a, 97b function as protective films when a groove shape is patterned on the first mask layers 95a, 95b at the subsequent step. The second mask layers 97a, 97b are preferably formed of a material having a corrosion resistance with respect to etching of the first mask layers 95a, 95b. For example, if the first mask layers 95a, 95b are formed by using silicon oxide, the second mask layers 97a, 97b may be formed by growing a photosensitive resist to a film thickness of 1 μm.
Subsequently, as depicted in
Subsequently, as depicted in
As a result, as depicted in
Subsequently, as depicted in
Subsequently, the second mask layers 97a, 97b and the processed first mask layers 96a, 96b are removed. As a result, the base materials 13a to 13d of the hairspring 108d as depicted in
The processed mask layers 96a, 96b may be removed, for example, by immersing the silicon substrate 62 in a known etchant mainly composed of hydrofluoric acid. The second mask layers 97a, 97b may be removed, for example, by immersing the silicon substrate 62 in a liquid of an organic solvent such as acetone. Subsequently, the hairspring 108d depicted in
As described above, the manufacturing method according to the fourth embodiment is a method of manufacturing the hairspring 108d provided with the groove portions 71a to 71d and the groove portions 72a to 72d that are stepped portions in the spring arms 203a to 203d and provided with the intermediate films 53a to 53d and the buffer films 23a to 23d in the groove portions 71a to 71d and the groove portions 72a to 72d as is the case in the third embodiment described above, and the groove portions serving as the stepped portions may be formed after the step of forming the outer shape. Although the manufacturing method of the fourth embodiment is described as the manufacturing method in which the intermediate films 53a to 53d and the buffer films 23a to 23d are formed in the groove portions 71a to 71d and the groove portions 72a to 72d having a concave shape, convex-shaped steps may also be manufactured by the same manufacturing method as is the case in the third embodiment.
An anchor 107 will be described as a drive mechanism of a timepiece incorporating a timepiece component of a fifth embodiment according to the present invention manufactured by a manufacturing method according to the fifth embodiment according to the present invention. In the fifth embodiment, portions identical to those of the first to fourth embodiments described above are denoted by the same reference characters used in the first to fourth embodiments and will not be described.
The anchor 107 regularly advances and stops the escape wheel 106 attempting to rotate according to the power transmitted through the train wheel 105. The anchor 107 includes one beam portion 6 and two arm portions 7a, 7b extending in three respective different directions from a shaft hole 10 that is the rotation center of the anchor 107.
A box portion 8 opened in a U shape is provided at a tip of the beam portion 6. As an impulse pin performs a rotational reciprocating motion in a regular cycle according to the hairspring 108 (108a to 108c) and comes into contact with the box portion 8, the anchor 107 reciprocates in a regular cycle around the shaft hole 10.
Stone slots 9a, 9b are provided at tips of the arm portions 7a, 7b. Components called pallet stones are pushed and fixed into the stone slots 9a, 9b. The regular motion transmitted from the hairspring 108 (108a to 108c) through the impulse pin to the anchor 107 is transmitted to the escape wheel 106 by flicking the escape wheel 106 with the pallet stones so as to advance and stop the escape wheel 106.
In the balance 104 as described above, the transmission efficiency of the power generated by the hairspring 108 (108a to 108c) may be increased by achieving the weight reduction of the components. Therefore, in the anchor 107 of the fifth embodiment, silicon having a light weight and a favorable processability is used as the first material forming the base material 15 of the anchor 107.
As described above, since the anchor 107 of the fifth embodiment has the base material 15 formed by using silicon, the silicon forming the base material 15 may be processed by using the Deep RIE technique. For example, as depicted in
The anchor 107 of the fifth embodiment may be prevented from being damaged due to a strength reduction attributable to hollowing, by forming an intermediate film 53 on the surface of the base material 15 and further forming a buffer film 24 as an upper layer on the intermediate film 53. In particular, by providing the intermediate film 53 formed by using the various materials described above on the surface of the base material 15, the brittleness of silicon may be alleviated and, additionally, by providing on the surface of the intermediate film 53 the buffer film 24 formed by using the second material having a tenacity higher than that of silicon used as the first material, external impact to the anchor 107 may be mitigated to prevent a damage such as cracking and chipping due to stress concentration at corners, etc.
The box portion 8 is a portion coming into direct contact with the impulse pin and, if the buffer film 24 is provided on the surface of the box portion 8, the transmission efficiency of the force from the impulse pin is reduced. Therefore, in the anchor 107, as depicted in
In the timepiece component such as the anchor 107, the interlayer 53 of the box portion 8 may be removed in addition to the buffer film 24 of the box portion 8 depending on the specifications of the mechanical timepiece using the timepiece component, so as to expose the first material (in this example, silicon) that is the base material 15. As a result, the force from the impulse pin may efficiently be transmitted to the escape wheel 106.
In the fifth embodiment, the anchor 107 is formed into a hollow shape by providing the multiple holes 12 penetrating along the thickness direction; however, the shape of the anchor 107 is not limited thereto. For example, as described in the third embodiment, a groove portion serving as a stepped portion may be provided on the surface of the anchor 107. As a result, the weight may be reduced further in addition to a weight reduction achieved by forming the base material 15 from silicon.
If the weight is reduced by providing the groove portion in this way, the buffer intermediate film 53 and the buffer film 24 may be provided along the shape of the groove portion or the groove portion may be filled with the buffer film 24. As a result, damage may be prevented from occurring due to reduced strength attributable to hollowing.
In the fifth embodiment, the anchor 107 is taken as an example of a timepiece component reduced in weight by hollowing and prevented from being damaged due to a strength reduction attributable to hollowing in the description; however, this is not a limitation. Such a timepiece component may be achieved by other timepiece components such as gears (a wheel and pinion, an escape wheel) and a balance wheel, instead of, or in addition to, the anchor 107.
A gear will be described as a drive mechanism of a timepiece incorporating a timepiece component of a sixth embodiment according to the present invention manufactured by a manufacturing method according to the sixth embodiment according to the present invention. In the sixth embodiment, portions identical to those of the first to fifth embodiments described above are denoted by the same reference characters used in the first to fifth embodiments and will not be described.
As described above, in the gear 331 of the sixth embodiment, by using silicon to form the base material 16, the weight of the gear 331 is reduced and, by providing the intermediate film 54 and the buffer film 25 on the inner circumferential surface of the shaft hole 331, external impact to the gear 331 may be mitigated to prevent a damage such as cracking and chipping due to stress concentration on corners etc.
An electret will be described as a timepiece component of a seventh embodiment according to the present invention manufactured by a manufacturing method according to the seventh embodiment according to the present invention. In the seventh embodiment, portions identical as those of the first to sixth embodiments described above are denoted by the same reference characters used in the first to sixth embodiments and will not be described.
The electret 340 includes a shaft hole 351 into which a shaft 341 is fitted. The electret 340 includes charged bodies 342 arranged radially from the shaft 341, around the shaft 341. Charged films are provided on front surfaces of the charged bodies 342. The charged films are positively or negatively charged by being subjected to a treatment such as corona discharge.
Openings 343 are provided between the charged bodies 342 along the circumferential direction of a circle around the shaft 341. As a result, the electret 340 may be reduced in weight. The charged bodies 342 are connected to the shaft 341 via an elastic member not depicted. The electret 340 is configured to perform an oscillating motion around the shaft 341 when vibration is externally applied.
The electret 340 of the sixth embodiment includes a base material formed by processing a silicon substrate by using the Deep RIE technique. The shape of the electret 340 is formed by the base material. The electret 340 has an intermediate film and a buffer film (both not depicted) provided at positions other than the portions provided with the charged films, i.e., other than the front surfaces of the charged bodies 342. The intermediate film and the buffer film are provided in all the portions other than the portions provided with the charging films and are also provided on the inner circumferential surface of the shaft hole 351.
The intermediate film is provided to cover the surface of the base material of the electret 340 other than the front surfaces of the charged bodies 342. The buffer film is stacked as an upper layer on the intermediate film and is provided to cover the charged bodies 342 except the front surfaces. The intermediate film and the buffer film are respectively formed by using the same materials as those in the embodiments described above.
While a weight reduction is required, the electret 340 described above is an extremely fine component and therefore may cause a concern about reduced resistance to external impact when formed by using silicon, etc. Since the electret 340 of the sixth embodiment has the intermediate film and the buffer film provided at positions other than the front surfaces of the charged bodies 342 on the surface of the base material, a weight reduction may be achieved by forming the base material from silicon while the external impact may be mitigated by the intermediate film and the buffer film.
Additionally, the electret 340 has the intermediate film and the buffer film provided on the inner circumferential surface of the shaft hole 351 so that the inner circumferential surface of the shaft hole 351 and the outer circumferential surface of the shaft 341 come into contact with each other via the buffer film. As a result, even if an impact is applied to the electret 340 when the shaft 341 is fitted into the shaft hole 351, the impact may be mitigated. Therefore, the electret 340 may be prevented from breaking or cracking when the shaft 341 is fitted into the shaft hole 351.
A shaft stone will be described as a timepiece component of an eighth embodiment according to the present invention manufactured by a manufacturing method according to the eighth embodiment according to the present invention. In the eighth embodiment, portions identical to those of the first to seventh embodiments described above are denoted by the same reference characters used in the first to seventh embodiments and will not be described.
In the mechanical timepiece, for example, as depicted in
Rather than being in the same shape to which the shaft stone 361 is exactly fitted into the cutout 363, the cutout 363 allows the multiple projecting portions 362a projecting toward the inside of the cutout 363 to come into contact with the outer circumferential surface of the shaft stone 361 so as to support the shaft stone 361. The cutout 363 causes a contact force to act on the shaft stone 361 via the projecting portions 362a in directions indicated by arrows so as to support the shaft stone 361.
When the shaft stone 361 is held by causing the projecting portions 362a to come into contact with the shaft stone 361, the projecting portions 362a must be brought into strong contact with the shaft stone 361 for reliable holding; however, the strong contact places a burden on the shaft stone 361 at the positions of contact with the projecting portions 362a. On the other hand, if the contact force of the projecting portions 362a against the shaft stone 361 is weak, it is difficult to sufficiently hold the shaft stone 361. Particularly when the shaft stone 361 is arranged at the outer end portion (outer edge) of the bottom plate 362, it is difficult to hold the shaft stone 361.
In this regard, the shaft stone 361 of the eighth embodiment is formed by providing an intermediate film on a surface of a base material formed by using ruby, silicon, etc. as a first material and providing a buffer film as an upper layer on the intermediate film (detailed illustrations and reference characters of both films are not depicted). Thus, the base material of the shaft stone 361 is covered with the interlayer film and the buffer film.
By achieving the shaft stone 361 having the intermediate film and the buffer film provided on the surface of the base material in this way, the shaft stone 361 may be held reliably without damaging the shaft stone 361 even when the projecting portions 362a are brought into strong contact with the shaft stone 361 so as to strongly hold the shaft stone 361.
The shaft stone 361 is not limited to the shape depicted in
By using the shaft stone 371 and the cutout 373 having such a shape, the shaft stone 371 may be held stably. As a result, the shaft hole 371a may be arranged at a position close to the end portion (outer edge) of the bottom plate 362. The shape of the shaft stone is not limited to the shapes depicted in
A backlash compensating member will be described as a timepiece component of a ninth embodiment according to the present invention manufactured by a manufacturing method according to the ninth embodiment according to the present invention. The backlash compensating member is provided in a mechanism mutually engaged with a gear (or screw) to transmit a motion such as the train wheel 105 and a screw in the mechanical timepiece so as to compensate a gap (so-called backlash) intentionally provided in the direction of motion of the gear (or screw) in the mechanism. The backlash compensating member is described as a conventional technique in Japanese Patent No. 4851945, for example.
The backlash compensating member is provided, for example, at a position of a tooth (or screw thread) at which a gear (or screw) is engaged with an engagement counterpart. Alternatively, the backlash compensating member is provided between the gear (or screw) and the engagement counterpart. The backlash compensating member includes a tooth portion engaged with the gear (or screw), and rotates in conjunction with the gear (or screw) when the rotation of the gear (or screw) is transmitted through the tooth portion. The tooth portion is configured to elastically deform with respect to the rotation direction. This allows the backlash compensating member to compensate a backlash between the gear (or screw) and the engagement counterpart.
In this backlash compensating member, at least the tooth portion is made up of a base material, and the intermediate and buffer films described above are provided on the tooth portion made up of the base material. As a result, an impact caused by transmission of power of the gear (or screw), etc. may be mitigated so as to prevent cracking or chipping of the backlash compensating member attributable to a stress concentrating at the tooth portion due to a collision of the gear (or screw) against the tooth portion of the backlash compensating member. Additionally, by providing the buffer film, the impact may be mitigated, so that the backlash compensating member and the gear or the screw, etc. colliding with the backlash compensating member may be prevented from being damaged.
As described above, the timepiece component and the method of manufacturing a timepiece component according to the present invention are useful for a timepiece component constituting a mechanical component in a timepiece and a method of manufacturing the timepiece component and is particularly suitable for a timepiece component used in a speed governing mechanism of a mechanical timepiece and a method of manufacturing the timepiece component.
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| WO2016/093354 | 6/16/2016 | WO | A |
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