This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2015-175603, filed on Sep. 7, 2015, and the entire contents of which are incorporated herein by reference.
The present invention relates to an electronic timepiece.
In the related art, there are known electronic timepieces, each of which has a plurality of motors such as stepping motors, and an antenna for receiving a standard radio wave which is a long radio wave, and performs various operations, such as time correction based on the standard radio wave.
If the operation accuracy of the motors is regarded as important, it is preferable to dispose antimagnetic plates for magnetically shielding the motors from external magnetic fields which may exert influence on the operations of the motors.
However, the antimagnetic plates are made of a material having high relative-permeability, and if such members having high relative-permeability are disposed near the antenna, it becomes easier for eddy current to occur, and loss of electric energy (eddy-current loss) occurs, whereby the receiving sensitivity of the antenna decreases.
For this reason, for example, in Japanese Patent Application Laid-Open No. 2014-062852, it is proposed a technology in which antimagnetic plates for magnetically shielding motors from external magnetic fields are provided and an antenna is disposed so as not to overlap the antimagnetic plates.
However, in a case where an electronic timepiece is a small instrument such as a wristwatch, since every module should be assembled in a limited space of the inside of a case, inevitably, motors and an antenna are disposed close to one another.
In this regard, in the technology disclosed in Japanese Patent Application Laid-Open No. 2014-062852, the antimagnetic plates are formed in different shapes such that the antimagnetic plates do not overlap the antenna while covering the motors.
However, significant manufacturing cost is required in making the antimagnetic plates in different shapes, and the shapes of the antimagnetic plates should be changed depending on the assembly position of the antenna. Therefore, there is a problem that it is impossible to commoditize the antimagnetic plates.
Further, according to the layout of the motors and the antenna, even though the antimagnetic plates have different shapes, it may be difficult to provide sufficient distances between each antimagnetic plate and the antenna, and it may be apprehended that the receiving sensitivity of the antenna will decrease.
In an electronic timepiece which performs time correction on the basis of a standard radio wave, a decrease in the receiving sensitivity of an antenna causes the intrinsic timepiece performance to deteriorate.
For this reason, in electronic timepieces, the antimagnetic properties of motors have been sacrificed to some extent in order to secure the radio-wave reception performance of antennae.
An object of the present invention is to provide an electronic timepiece capable of securing the radio-wave reception performance of an antenna while securing the operation accuracy of motors.
An electronic timepiece according to the present invention comprises:
an antenna;
a motor including a stator, a coil magnetically connected to the stator, and a rotor magnet disposed in a receiving part of the stator; and
a belt-like antimagnetic plate configured to have a width equal to or greater than a diameter of the rotor magnet and to cover a portion of the motor including the rotor magnet
Hereinafter, preferred embodiments of an electronic timepiece according to the present invention will be described with reference to the accompanying drawings.
Although technically preferable various limitations are added to the embodiments to be described below in order to embody the present invention, the scope of the invention is not limited to the following embodiments and examples shown in the drawings.
[First Embodiment]
First, with reference to
As shown in
The timepiece case 1 of the present embodiment is formed in a short column shape having a hollow, and on the front side of the timepiece 100 (the viewable side of the timepiece), a windshield member 11 made of transparent glass or the like is attached.
Also, on the back side of the timepiece 100, a back lid (not shown) is attached.
Both end portions of the timepiece case 1 in the upward and downward direction of
Also, the timepiece 100 has an operation button 13 on a side portion or the like of the timepiece case 1.
The inserted end portion of the operation button 13 is connected to a module (not shown) stored inside the timepiece case 1. Also, the operation button 13 is configured such that a user can perform various operations by pressing or rotating the operation button 13.
In the space between the timepiece case 1 and the windshield member 11, a display unit 14 is provided.
The display unit 14 of the present embodiment is an analog type display unit having a dial 15, and hands 17 such as a time hand, a minute hand, and a second hand disposed above the dial 15 as shown in
On the circumferential portion of the front side of the dial 15, hour markers 16 are disposed as indicators of time to be shown by the hands 17.
However, the configuration and the like of the display unit 14 are not limited to the example shown in
Inside the timepiece case 1, for example, a module (not shown) including a timepiece movement (not shown) which is composed of gear train mechanisms and motors 4 (see
The hand spindle 18 of the present embodiment is a spindle in which a plurality of rotating shafts for the hour hand, the minute hand, the second hand, and the like are arranged so as to overlap on the same axis, and the hands 17 (for example, the hour hand, the minute hand, and the second hand) are connected to the rotating shafts of the hand spindle 18, respectively.
If the hand spindle 18 rotates according to an operation of the timepiece movement, the various hands 17 fit on the individual rotating shafts of the hand spindle 18 individually rotate around the hand spindle 18 over the front surface of the dial 15.
However, the number and the like of hands 17 which are attached to the hand spindle 18 and are movable around the hand spindle 18 are not limited to the example shown the drawings. For example, only one hand 17 may be provided, or a function hand for performing display related to various functions may be provided as a hand 17 in addition to the hour hand, the minute hand, and the second hand. Also, besides the hand spindle 18 for supporting the hands such as the hour hand, a hand spindle for supporting the function hand may be separately provided.
In the present embodiment, as shown in
However, the number, arrangement, and the like of the antenna 3 and the motors 4 shown in
The antenna 3 of the present embodiment is for receiving a standard radio wave including time information.
The antenna 3 has a core 3 made of, for example, a magnetic material such as an amorphous metal or ferrite, and a coil 32 wound around the core.
The timepiece 100 performs various operations, such as time correction based on a standard radio wave received by the antenna 3.
The motors 4 are for operating operation units. In the present embodiment, six motors 4 (that is, the motors 4a to 4f) are provided.
In the present embodiment, three hands 17 (that is, the second hand, the minute hand, and the hour hand) are shown as operation units in the drawings. However, operation units which are provided in the timepiece 100 are not limited thereto. More operation units may be provided.
In
As shown in
The motor 4 (each of the motors 4a to 4f) is a stepping motor having a rotor 43 which rotates by a predetermined step angle if an appropriate drive pulse is applied to a coil 42 magnetically connected to a stator 41.
The stator 41 is a plate-like member configured to extend in the longitudinal direction of the motor 4 (the transverse direction in
The stator 41 is mad of a high permeability material such as permalloy. However, a material for making the stator 41 is not limited to permalloy.
As shown in
The receiving part 411 is a substantially circular hole. In the present embodiment, the receiving part is disposed at an approximately central portion in the longitudinal direction of the stator 41 (in the present embodiment, this direction is the transverse direction of
Also, on the inner surface of the receiving part 411, two inner recesses (inner notches) 412 are formed at positions substantially facing each other.
The inner recesses 412 constitute positioning parts for determining a position (a stable stop position) for the rotor 43 to stably stop.
A rotor magnet 431 of the rotor 43 has a tendency to stick to a closer metal. For this reason, when two poles of the rotor magnet 431 face parts other than the inner recesses 412, that is, the polarization position of the rotor magnet 431 of the rotor 43 faces two inner recesses 412, the holding torque of the motor 4 is maximized. Therefore, in a power cutoff state where any drive pulse is not applied to the coil 42 to be described below, the rotor 43 magnetically stably stops such that the polarization position of the rotor magnet 431 faces the inner recesses 412 as shown in
Also, the inner recesses 412 are disposed such that a line connecting the deepest parts of the inner recesses 412 and passing through the center of the circle shape of the receiving part 411 forms a certain angle with a line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411.
The certain angle slightly varies depending on various conditions such as the specification of the motor 4, and it is preferable to appropriately set the certain angle between 30° to 50°. In the present embodiment, the certain angle is set to 45° (see
Also, on the outer surface of the stator 41, a pair of outer recesses (outer notches) 413 are formed so as to substantially face each other with the receiving part 411 interposed therebetween.
The outer recesses 413 are for determining a magnetic flux saturation part of the stator 41.
Parts of the stator 41 which are positioned between the outer recesses 413 and the receiving part 411 have narrow widths, and thus become saturable parts in which magnetic flux saturation can easily occur as compared to the other part.
Each saturable part is configured such that it is not magnetically saturated by magnetic fluxes of the rotor 43, and when the coil 42 (to be described below) is excited, the saturable part is magnetically saturated, thereby becoming a magnetic flux saturation part having high magneto-resistance.
However, the shapes, sizes, arrangements, and the like of the inner recesses (inner notches) 412 and the outer recesses (outer notches) 413 are not limited to the examples shown in the drawings.
The coil 42 is formed by winding wire around a portion of an elongated coil core 421.
The coil core 421 is made of a high permeability material such as permalloy.
Both end portions of the coil core 421 in the longitudinal direction are magnetically joined with both end portions of the stator 41 in the longitudinal direction, respectively, whereby the coil 42 is magnetically connected to the stator 41.
The motor 4 is fixed on the main plate 21, for example, by superimposing both end portions of the coil core 421 in the longitudinal direction and both end portions of the stator 41 in the longitudinal direction and screwing them to the main plate 21.
As shown in
The rotor magnet 431 is magnetized to have two poles (an S pole and an N pole) in a radial direction.
As a magnet for constituting the rotor magnet 431, for example, a permanent magnet such as a rare-earth magnet (for example, a samarium-cobalt magnet) can be suitably used. However, the type of a magnet for constituting the rotor magnet 431 is not limited thereto.
At the center of the circular shape of the rotor magnet 431, a rotor shaft 432 is provided.
As shown in
The rotor 43 is stored in the receiving part 411 of the stator 41 (to be described below), such that the rotor can rotate around the rotor shaft 432. In the present embodiment, the rotor 43 can rotate in the receiving part 411 by a predetermined step angle if a drive pulse is applied to the coil 42.
On the rotor shaft 432, a rotor pinion 433 is provided. The rotor pinion 433 is connected to a component such as a gear (not shown) constituting a gear train mechanism for moving a hand 17 of the timepiece 100. Therefore, if the rotor 43 rotates, the component, such as a gear, engaged with the rotor pinion 433 rotates.
As shown in
Each individual antimagnetic plate 5 has a belt-like member configured to have a width equal to or greater than the diameter of the rotor magnet 431 of a corresponding motor 4 and cover a portion of the motor 4 including the rotor magnet 431.
Specifically, as shown in
The first antimagnetic portion 51 has the width equal to or greater than the diameter of the rotor magnet 431. Further, the first antimagnetic portion 51 is formed such that the length of the first antimagnetic portion in the extension direction is longer than the length of the stator 41 in the longitudinal direction. Also, the second antimagnetic portion 52 has the width equal to or greater than the diameter of the rotor magnet 431. Further, the second antimagnetic portion 52 is formed such that the length of the second antimagnetic portion in the extension direction is longer than the length of the stator 41 of the motor 4 in a direction perpendicular to the longitudinal direction of the stator.
Here, the width equal to or greater than the diameter of the rotor magnet 431 means a width which is substantially the same as or larger than the diameter of the rotor magnet 431. In a case of setting a width larger than the diameter of the rotor magnet 431, it is possible to appropriately set a width according to the size of the motor 4, the antimagnetic property which is obtained, and so on.
It is preferable to dispose the individual antimagnetic plates 5 with slight gaps from the motors 4 such that the antimagnetic plates are not in contact with the motors 4. In the present embodiment, the individual antimagnetic plates 5 are disposed on the circuit board 23 so as to correspond the motors 4, respectively.
In other words, in the present embodiment, as shown in
However, the layout of the individual antimagnetic plates 5 is not limited to that example. For example, the individual antimagnetic plates 5 may be disposed on one surface of the main plate 21 (for example, the lower surface of the main plate 21 in
The individual antimagnetic plates 5 are made of, for example, SPCC (cold-reduced carbon steel sheets and strips).
However, since the individual antimagnetic plates 5 need only to gather magnetic fields, a material for making the individual antimagnetic plates 5 is not limited to SPCC. For example, the individual antimagnetic plates may be made of permalloy or the like.
Now, the operation of the timepiece (electronic timepiece) 100 according to the present embodiment will be described with reference to
When the timepiece 100 is assembled, the antenna 3 and the motors 4 are disposed on the main plate 21, and the bearing member 22 is disposed on the main plate with the antenna 3 and the motors 4 interposed therebetween, and the circuit board 23 is superimposed thereon.
Subsequently, at positions on the circuit board 23 corresponding to the motors 4, the individual antimagnetic plates 5 are disposed, such that the first antimagnetic portions 51 are positioned along the longitudinal directions of the stators 41, and the second antimagnetic portions 52 are positioned along directions perpendicular to the first antimagnetic portions 51.
Then, the main plate 21 having the antenna 3 and the motors 4 disposed thereon, the bearing member 22, and the circuit board 23 having the individual antimagnetic plates 5 disposed thereon are stored in the module.
Subsequently, the module, the display unit 14 including the dial 15, and the like are stored inside the timepiece case 1, and the windshield member 11 is attached to the viewable-side opening part of the timepiece case 1, and the back lid is attached to the back-side opening part of the timepiece case.
As a result, the timepiece 100 is completed.
If an external magnetic field enters the timepiece 100, the external magnetic field acts on the motors 4, thereby influencing the operation accuracy of the motors 4. Especially, each motor 4 is easily influenced by an external magnetic field entering the motor from a direction perpendicular to the longitudinal direction of the stator 41 and an external magnetic field entering the motor from a direction along the longitudinal direction, as shown in
First, with reference to
As described above, the receiving part 411 has one pair of inner recesses 412 as positioning parts for determining a position for the rotor 43 to stably stop. The inner recesses 412 are disposed such that the line connecting the deepest parts of the inner recesses 412 and passing through the center of the circle shape of the receiving part 411 forms 45° with the line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411. Therefore, normally, in a power cutoff state, the rotor 43 magnetically stably stops such that the polarization position of the rotor magnet 431 faces the inner recesses 412. Thereafter, if a drive pulse is applied to the coil 42, this state becomes an initial state, and drive control is performed such that the rotor 43 rotates.
However, in a case where an external magnetic field passes through the motor in a direction perpendicular to the longitudinal direction of the stator 41, the upstream side of the flow of the external magnetic field becomes an N pole, and the downstream side becomes an S pole. As shown in
However, the direction of the external magnetic field which causes the above described state is not strictly limited to a direction perpendicular to the longitudinal direction of the stator 41. In a case where an external magnetic field passes through the motor while forming an angular range between −45° and 45° with a line extending at 90° with respect to the line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411 as shown in
Also, as described above, the positions to form the inner recesses 412 for determining the stop position of the rotor 43 are determined such that the line connecting the deepest parts of the inner recesses 412 and passing through the center of the circle shape of the receiving part 411 forms a predetermined angle with the line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411. However, the positions of the inner recesses are not strictly limited to the case where both lines form 45°, and have a slight tolerance. However, even in a case where the positions of the inner recesses 412 are slightly shift, in a case where an external magnetic field passes through the motor while forming an angular range between −45° and 45° with the line extending at 90° with respect to the line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411, it is apprehended that the above described situation will occur.
In this regard, each individual antimagnetic plate 5 of the present embodiment has the second antimagnetic portion 52 configured to extend in a direction perpendicular to the longitudinal directions of the stator 41. Therefore, an external magnetic field flowing into the motor from a direction perpendicular to the longitudinal direction of the stator 41 (that is, a direction forming 90° with the line extending in the longitudinal direction of the stator 41 through the center of the circle shape of the receiving part 411), or from a range between −45° and 45° with respect to the corresponding direction is guided to the second antimagnetic portion 52, and flows along the second antimagnetic portion 52 without acting on the motor 4.
Especially, in the present embodiment, the second antimagnetic portion 52 is formed to be longer than the length of the stator 41 of the motor 4 in a direction perpendicular to the longitudinal direction of the stator. Therefore, as shown in
Now, with reference to
For example, it is assumed a case where a drive pulse has been applied to the coil 42, whereby magnetic fluxes have been generated in a direction shown by an outlined arrow in
In this regard, the individual antimagnetic plates 5 of the present embodiment each have the first antimagnetic portion 51 configured to extend in the longitudinal direction of the stator 41. Therefore, the external magnetic field flowing into the motor along the longitudinal direction of the stator 41 is guided to the first antimagnetic portion 51, and flows through the first antimagnetic portion 51 without acting on the motor 4.
Especially, in the present embodiment, the first antimagnetic portion 51 is formed to be longer than the length of the stator 41 of the motor 4 in the longitudinal direction of the stator. Therefore, as shown in
Also, in a case where a drive pulse is applied to the coil 42, whereby magnetic fluxes are generated in a direction shown by an outlined arrow in
In this case, if an external magnetic field acts from a direction as shown by solid lines in
In this regard, in a case where the individual antimagnetic plate 5 has the first antimagnetic portion 51 configured to extend in the longitudinal direction of the stator 41 like in the present embodiment, the external magnetic field entering the motor from such a direction that it can nullify the flows of the magnetic field lines is guided to the first antimagnetic portion 51, and passes through the first antimagnetic portion 51, without acting on the motor 4. Therefore, it is possible to prevent the flows of the magnetic field lines from being nullified by the external magnetic field.
As shown in
However, in a case of disposing the antimagnetic plate 50 so as to cover all motors 4 as described above, a portion of the antimagnetic plate 50 is disposed at a position close to the antenna 3.
Since the antimagnetic plate 50 is a member made of a high relative-permeability material, if the antimagnetic plate 50 is in the vicinity of the antenna 3 when the antenna 3 receives a radio wave, magnetic fluxes easily pass through the antimagnetic plate 50.
If magnetic fluxes pass through the antimagnetic plate 50, eddy current occurs, and loss of electric energy (eddy-current loss) occurs, whereby the receiving sensitivity of the antenna 3 decreases.
In order to prevent such eddy current from occurring, it is preferable to dispose the antimagnetic plate 50 as far away from the antenna 3 as possible. However, in this case, motors 4 also cannot be disposed near the antenna 3. Therefore, in a case where a plurality of motors 4 should be mounted, the layout of the motors is limited.
Also, if all of the motors 4 including the coils 42 are covered with the antimagnetic plate 50, some of magnetic fluxes generated by the motors 4 are absorbed by the antimagnetic plate 50, whereby the performance of the motors 4 may deteriorate.
In this regard, in the timepiece 100 of the present embodiment, the minimal individual antimagnetic plates 5 capable of excluding external magnetic fields which may exert negative influence on the motors 4 are provided for the motors 4, respectively. Therefore, even though the motors 4 are disposed near the antenna 3, the influence of the individual antimagnetic plates 5 on the antenna 3 is less, and occurrence of eddy current attributable to the individual antimagnetic plates 5 is suppressed, and it is possible to maintain good receiving sensitivity of the antenna 3.
Also, the second antimagnetic portion 52 of each individual antimagnetic plate 5 is disposed so as to cover a portion of the coil 42 of a corresponding motor 4. Unlike a case where all motors 4 are covered with the antimagnetic plate 50 like in the related art, since each second antimagnetic portion 52 is disposed so as to extend in a direction perpendicular to the longitudinal direction of a corresponding stator 41 which is the direction of the flow of magnetic fluxes generated by a corresponding motor 4, it is difficult for the second antimagnetic portion 52 to influence the magnetic fluxes generated by the motor 4, and it is possible to improve the antimagnetic property without lowering the performance of the motor 4.
As described above, according to the present embodiment, a belt-like individual antimagnetic plate 5 having a width equal to or greater than the diameter of the rotor magnet 431 of a corresponding motor 4 is disposed so as to cover a portion of the motor 4.
Therefore, the motors 4 are magnetically shielded by the individual antimagnetic plates 5, whereby it becomes difficult for an external magnetic field which may influence the operations of the motors 4 to reach the motors 4. Therefore, problems such as malfunction of the motors 4 are prevented, and the operation accuracy is improved, and it is possible to satisfy high antimagnetic property standards as required, for example, for antimagnetic timepieces, in JIS (Japanese Industrial Standards).
In other words, it is possible to improve the antimagnetic properties of the motors 4 by preventing an external magnetic field from acting on the rotor magnets 431 most likely to be adversely influenced by the external magnetic field.
Therefore, even in a case where the motors 4 having the individual antimagnetic plates 5 are disposed near the antenna 3, since the individual antimagnetic plates 5 are small, occurrence of eddy current is less as compared to the case of providing the antimagnetic plate 50 to cover all motors 4, and it is possible to maintain good receiving sensitivity of the antenna 3.
Also, in case of the planar antimagnetic plate as shown in
Also, as described above, especially, as shown in
Further, the first antimagnetic portion 51 is formed such that the length of the first antimagnetic portion in the extension direction is longer than the length of the stator 41 of the motor 4 in the longitudinal direction of the stator, and the second antimagnetic portion 52 is formed such that the length of the second antimagnetic portion in the extension direction is longer than the length of the stator 41 of the motor 4 in a direction perpendicular to the longitudinal direction of the stator. Therefore, it is possible to more effectively release an external magnetic field gathered by the individual antimagnetic plate 5 to the outside of the motor 4.
Also, since the individual antimagnetic plate 5 is small, as compared to a case of providing an antimagnetic plate to cover all motors like in the related art, it is possible to reduce the weight of the whole product while improving the antimagnetic properties of the motors. Further, as compared to the antimagnetic plate for covering all motors, it is possible to make the individual antimagnetic plates 5 with a smaller amount of material, and it is possible to reduce the cost of the timepiece.
Also, since the present embodiment is used in the timepiece (electronic timepiece) 100 which has the antenna 3 for receiving radio waves and where the individual operation units are driven by the motors 4, it is possible to secure the radio-wave receiving sensitivity of the antenna 3 while securing the operation accuracy of the motors 4. Therefore, it is possible to implement the timepiece 100 capable of accurate time adjustment based on a standard radio wave, without sacrificing the antimagnetic property.
Also, since the present embodiment is used, the degree of freedom of the arrangement relation between the antenna 3 and the motors 4 is improved, whereby it is possible to expect an effect that the degree of freedom of product design increases.
Also, in the present embodiment, a case where each of the individual antimagnetic plates 5 is one member in which the first antimagnetic portion 51 which is a belt-like portion configured to extend in the longitudinal direction of a corresponding stator 41 and the second antimagnetic portion 52 which is a belt-like portion configured to extend in a direction perpendicular to the first antimagnetic portion 51 are connected has been described as an example. However, the first antimagnetic portion 51 configured to extend in the longitudinal direction of the stator 41 and the second antimagnetic portion 52 configured to extend in a direction perpendicular to the first antimagnetic portion 51 may be separate members.
For example, if the first antimagnetic portions 51 and the second antimagnetic portions 52 are belt-like members having the same shape, and the individual antimagnetic plates 5 are configured by manufacturing a plurality of belt-like members and combining and disposing the belt-like members in a cross shape, it is possible to easily make the individual antimagnetic plates 5 at a low cost.
Also, in a case where each of the individual antimagnetic plates 5 has the first antimagnetic portion configured to extend in the longitudinal direction of a corresponding stator 41 and the second antimagnetic portion configured to extend in a direction perpendicular to the first antimagnetic portion, if the first antimagnetic portion 51 and the second antimagnetic portion 52 are separate members, one may be disposed on the front side of a corresponding motor 4 and the other may be disposed on the back side of the motor 4.
For example, in
Also, in the present embodiment, a case where the individual antimagnetic plates 5 are disposed on the front surface of the circuit board 23 (the upper surface in
For example, the antimagnetic plates may be disposed on the back surface of the circuit board 23 (the lower surface in
Also, the individual antimagnetic plates 5 may be disposed on the front and back of each of the motors 4 (the upper and lower surfaces in
Also, in this case, the individual antimagnetic plates 5 which are disposed on the front and back of each motor 4 (the upper and lower surfaces in
Also, in the present embodiment, a case where each individual antimagnetic plate 5 is an almost cross-shaped plate having both of a first antimagnetic portion 51 configured to extend in the longitudinal direction of a corresponding stator 41 and a second antimagnetic portion 52 configured to extend in a direction perpendicular to the first antimagnetic portion 51 has been described as an example. However, the shape of the individual antimagnetic plates is not limited to the cross shape.
For example, as shown in
Also, even in this case, it is preferable that each belt-like individual antimagnetic plate 71 which is configured to extend in the longitudinal direction of a corresponding stator 41 should be formed such that the individual antimagnetic plate has a width equal to or greater than the diameter of the rotor magnet 431 of a corresponding motor 4 and the length of the individual antimagnetic plate in the extension direction is longer than the length of the stator 41 of the motor 4 in the longitudinal direction of the stator. Also, it is preferable that each belt-like individual antimagnetic plate 72 which is configured to extend in a direction perpendicular to the longitudinal direction of a corresponding stator 41 should be formed such that the individual antimagnetic plate has a width equal to or greater than the diameter of the rotor magnet 431 of a corresponding motor 4 and the length of the individual antimagnetic plate in the extension direction is longer than the length of the stator 41 of the motor 4 in a direction perpendicular to the longitudinal direction of the stator.
The direction of an external magnetic field to influence the operation of a motor 4, that is, the direction of an external magnetic field to more strongly influence the motor 4, thereby causing the antimagnetic property of the motor 4 to decrease depends on the size and shape of the motor 4, and both of an external magnetic field entering the motor from the longitudinal direction of the stator 41 and an external magnetic field entering the motor from a direction perpendicular to the longitudinal direction of the stator 41 do not always make the operation of the motor instable.
Therefore, according to the specifications of the motors 4, it is conceivable either to dispose the individual antimagnetic plates 71 so as to extend in the longitudinal directions of the stators 41 as shown in
In this case where only the individual antimagnetic plates 71 are disposed to extend in the longitudinal directions of the stators 41 or only the individual antimagnetic plates 72 are disposed to extend in directions perpendicular to the longitudinal directions of the stators 41, since the areas of the antimagnetic plates are small, it is possible to further reduce the influence of the individual antimagnetic plates on the antenna 3, and it is possible to reduce the weight of the timepiece. Also, it is possible to reduce the manufacturing cost (material cost) of the individual antimagnetic plates.
Also, all of the individual antimagnetic plates which are provided in the timepiece 100 do not need to have the same shape, and individual antimagnetic plates having various shapes and forms as described above (that is, the cross-shaped individual antimagnetic plates 5, the belt-like individual antimagnetic plates 71 and 72, and the like) may be appropriately used for the individual motors 4.
[Second Embodiment]
Now, a second embodiment of the electronic timepiece according to the present invention will be described with reference to
As shown in
Further, at least with respect to some (in
In other words, the individual antimagnetic plates 5 which are disposed for the motors 4a to 4c are belt-like members configured to have widths equal to or greater than the diameters of corresponding rotor magnets 431 and cover portions of the motors 4 including the rotor magnets 431.
Further, in the present embodiment, the timepiece further includes a planar antimagnetic plate 8 configured to cover some or all of the motors 4 disposed outside the predetermined range from the antenna 3. The material and the like of the planar antimagnetic plate 8 are the same as those of the individual antimagnetic plates 5, and thus will not be described.
In the present embodiment, as shown in
Also, the shape and size of the planar antimagnetic plate 8, the number of motors 4 which are covered by the planar antimagnetic plate 8, and the like are not particularly limited.
The planar antimagnetic plate 8 does not need to cover all of the motors 4 disposed outside the predetermined range from the antenna 3, and may be configured to cover only some of them.
Also, only one planar antimagnetic plate 8 may be provided, or two or more planar antimagnetic plates may be provided.
Here, a reference for determining whether a motor 4 is inside the predetermined range from the antenna 3 is appropriately set on the basis of the extent to which the receiving sensitivity of the antenna 3 is influenced by providing an antimagnetic plate (the planar antimagnetic plate 8) to cover the whole of the motor 4. The influence on the receiving sensitivity decreases as the antimagnetic plate (the planar antimagnetic plate 8) gets further away from the antenna 3, and specifically, it is preferable to individually determine the specific distance, arrangement relation, and the like between the antenna 3 and each motor 4 in view of the level of the receiving sensitivity of the antenna 3, the size and the like of the timepiece case 1 where the antenna 3, the motors 4, and the like are assembled, and so on.
In the present embodiment, an example in which the motors 4 directly facing the antenna 3 (in
Also, the other configuration is the same as that of the first embodiment, and thus identical members are denoted by the same reference symbols and will not be described.
Now, the operation of the timepiece (electronic timepiece) 100 according to the present embodiment will be described.
First, with respect to each of the motors 4 disposed in the predetermined range from the antenna 3 (in
Then, with respect to the motors 4 disposed outside the predetermined range from the antenna 3 (in
In this case, the motors 4d to 4f are magnetically shielded from external magnetic fields by covering all of the motors 4 with the planar antimagnetic plate 8.
Also, the motors 4a to 4c disposed in the predetermined range from the antenna 3 are shielded from external magnetic fields from such directions that the magnetic fields may exert negative influence particularly on the operations of the motors 4, by efficiently gathering the external magnetic fields by the individual antimagnetic plates 5 which are relatively small in size and in which occurrence of eddy current is less. Therefore, the operation accuracy of the motors 4 is secured, without reducing the receiving sensitivity of the antenna 3.
The other points are the same as those of the first embodiment, and thus will not be described.
As described above, according to the present embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
In other words, in the present embodiment, only with respect to the motors 4a to 4c disposed in the predetermined range from the antenna 3, the individual antimagnetic plate 5 are provided, and the motors 4d to 4f disposed outside the predetermined range from the antenna 3 are magnetically shielded from external magnetic fields by the planar antimagnetic plate 8.
Therefore, as compared to the case of providing the individual antimagnetic plates 5 with respect to all motors 4, the number of components is smaller, and thus it is possible to achieve a reduction in the assembly man-hours, and the like.
Even in this case, since the motors 4a to 4c disposed in the predetermined range from the antenna 3 are shielded from external magnetic fields from such direction that the magnetic fields may exert negative influence particularly on the operations of the motors 4, by efficiently gathering the external magnetic fields by the individual antimagnetic plates 5, it is possible to minimize the influence of provision of the antimagnetic plates on the antenna 3. Therefore, the operation accuracy of the motors 4 is secured, without reducing the receiving sensitivity of the antenna 3.
Also, the shapes and configurations of the individual antimagnetic plates 5 which are applied for the motors 4 disposed in the predetermined range from the antenna 3 (in
For example, as described above, belt-like individual antimagnetic plates configured to extend in the longitudinal directions of the stators 41 (see the individual antimagnetic plates 71 of
Also, all of the individual antimagnetic plates do not need to have the same shape, and individual antimagnetic plates having various shapes and forms as described above may be appropriately used for the individual motors 4.
Also, in the present embodiment, a case where the individual antimagnetic plates 5 and the planar antimagnetic plate 8 are separately and independently provided has been described as an example. However, the configuration of the antimagnetic plates is not limited thereto, and some or all of the individual antimagnetic plates may be connected to the planar antimagnetic plate.
Specifically, as shown in
For example, in
In this case where some or all of the individual antimagnetic plates are connected to the planar antimagnetic plate, the number of components is smaller than that in the case of individually manufacturing and assembling the antimagnetic plates. Therefore, the assembly man-hours also decrease.
Also, since portions of the individual antimagnetic plates having less influence on the antenna 3 are connected to the planar antimagnetic plate, it is possible to more effectively gather external magnetic fields, without reducing the receiving sensitivity of the antenna 3, as compared to the case of individually providing the antimagnetic plates. Therefore, the operation accuracy of the motors 4 can be expected to be more surely improved.
However, all of the individual antimagnetic plates 82 may not need to be connected to the planar antimagnetic plate 8. For example, in
Also, the individual antimagnetic plates 82 connected to the planar antimagnetic plate 8 by the connection portions 823 may be connected to each other by a connection portion.
[Third Embodiment]
Now, a third embodiment of the electronic timepiece according to the present invention will be described with reference to
As shown in
Further, with respect to the plurality of motors 4 (in the present embodiment, the motors 4a to 4f), belt-like individual antimagnetic plates 9 (in
Similarly in the first embodiment, each individual antimagnetic plate 9 (in
Further, in the present embodiment, some or all of the individual antimagnetic plates 9 are connected by connection portions 93. Individual antimagnetic plates having longitudinal directions substantially aligned with each other are connected, whereby it is possible to improve the antimagnetic property in the connection direction.
Specifically, the individual antimagnetic plates 9a to 9c provided with respect to the motors 4a to 4c are connected by connection portions 93, thereby constituting an antimagnetic connection plate 90.
Similarly, the individual antimagnetic plates 9d to 9f provided with respect to the motors 4d to 4f are connected by connection portions 93, thereby constituting another antimagnetic connection plate 90.
In the present embodiment, a case where two antimagnetic connection plates 90 each including three individual antimagnetic plates 9 connected are provided has been described as an example. However, the configuration of the antimagnetic connection plates 90 is not limited thereto. For example, all of six individual antimagnetic plates 9a to 9f may be connected, thereby constituting one antimagnetic connection plate 90.
Also, the other configuration is the same as that of the first embodiment or the like, and thus identical members are denoted by the same reference symbols and will not be described.
Now, the operation of the timepiece (electronic timepiece) according to the present embodiment will be described.
First, with respect to the plurality of motors 4 (in
Then, as some of the individual antimagnetic plates 9 having longitudinal directions aligned with one another, the individual antimagnetic plates 9a to 9c provided with respect to the motors 4a to 4c are connected by the connection portions 93, thereby forming an antimagnetic connection plate 90. Similarly, as other antimagnetic plates having longitudinal directions aligned with one another, the individual antimagnetic plates 9d to 9f provided with respect to the motors 4d to 4f are connected by the connection portions 93, thereby forming another antimagnetic connection plate 90.
Even in this case, the motors 4a to 4f are shielded from external magnetic fields from such directions that the magnetic fields may exert negative influence particularly on the operations of the motors 4, by efficiently gathering the external magnetic fields by the individual antimagnetic plates 9a to 9f which are relatively small in size and in which occurrence of eddy current is less. Therefore, the operation accuracy of the motors 4 is secured, without reducing the receiving sensitivity of the antenna 3.
Further, since the individual antimagnetic plates 9a to 9c are connected by the connection portions 93, thereby constituting an antimagnetic connection plate 90, and the individual antimagnetic plates 9d to 9f are connected by the connection portions 93, thereby constituting another antimagnetic connection plate 90, in the connection directions, it is possible to expect higher magnetism gathering effect and an improvement in the antimagnetic property.
The other points are the same as those of the first embodiment or the like, and thus will not be described.
As described above, according to the present embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
In other words, in the present embodiment, the individual antimagnetic plates 9a to 9c are connected by the connection portions 93, thereby constituting an antimagnetic connection plate 90, and the individual antimagnetic plates 9d to 9f are connected by the connection portions 93, thereby constituting another antimagnetic connection plate 90. Therefore, in the connection directions, it is possible to expect higher magnetism gathering effect and an improvement in the antimagnetic property, as compared to the case using the separate individual antimagnetic plates 9a to 9f.
Also, since some or all of the individual antimagnetic plates 9 are connected into one member, the number of components is less than that in the case of separately and independently providing the individual antimagnetic plates 5 with respect to all motors 4. Therefore, it is possible to achieve a reduction in the assembly man-hours, and the like.
Although the embodiments of the present invention have been described above, the present invention is not limited to those embodiments, and it goes without saying that various modifications are possible without departing from the scope of the present invention.
For example, in each embodiment, the layout of the individual antimagnetic plates has been described with reference to a case where it is necessary to dispose the antimagnetic plates near the antenna 3. However, a situation in which the individual antimagnetic plates are disposed is not limited to the case of disposing the antimagnetic plates near the antenna 3.
For example, components (such as a magnetic sensor) may be influenced by antimagnetic plate if the antimagnetic plates are disposed near the components. In a case of mounting such components, if the individual antimagnetic plates shown in the embodiments are applied, it is possible to secure the accuracy of the components while improving their antimagnetic properties.
Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above described embodiments, and includes the scopes of inventions disclosed in claims and the scopes of their equivalents.
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2015-175603 | Sep 2015 | JP | national |
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