JP2014048200A - Rotational position detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational position detection device which is reasonably configured and achieves high reliability.SOLUTION: A rotational position detection device includes: a light emitting element 110 and a light receiving element 120 both mounted on a circuit board 300; and a light guide 130. The rotational position detection device is arranged so that a rotating body 10 is positioned in a path A of light emitted from the light emitting element 110. According to rotation of the rotating body 10, a transparent portion 11, provided on the rotating body 10, crosses the path A of the light, so that a rotational position of the rotating body 10 is detected. A case body 200 includes a first case component 210 and a second case component 220 which hold the rotating body 10 in between at both sides of the rotating body 10 in its rotation axis direction. The circuit board 300 is provided in the first case component 210, and the light guide 130 is provided in the second case component 220. On a surface of the second case component 220, which serves as an outer surface of the case body 200, is provided a light guide insertion depression 221 to which the light guide 130 is inserted.

Description

  The present invention relates to an apparatus for detecting a rotational position of a rotating body using a light emitting element and a light receiving element.

  As a rotational position detection device provided in the drive mechanism, a device configured to detect a light transmitting portion provided in a rotating body by arranging a light emitting element and a light receiving element so as to sandwich the rotating body is known. ing. This is a basic application form of a so-called transmissive photosensor. Further, the light emitting element and the light receiving element can be arranged on one side with respect to the rotating body by reversing the traveling direction of light using a light guide. Such a configuration has the advantage that the wiring structure inside the drive mechanism is simplified. Patent Documents 1 to 5 disclose a movement of an analog timepiece provided with this type of rotational position detection device.

JP 2002-107465 A JP 2009-198421 A Japanese Patent No. 4643941 JP 2010-203828 A JP 2010-281773 A

  As described above, when the light emitting element and the light receiving element are arranged on one side with respect to the rotating body, there is a great advantage that the wiring structure is simplified. It is necessary to set the part where the body is provided and to assemble it accurately. The inventor of the present application has studied the arrangement structure of the light guides in consideration of the manufacturability of the drive mechanism and has achieved the present invention.

  The present invention has been made in view of such circumstances, and an object of the present invention is to obtain a more reliable rotational position detection device configured more rationally.

  The invention described in claim 1 of the present application is provided in a drive mechanism (1) for rotating the rotating body (10), and in the rotational position detecting device (100) for detecting the rotational position of the rotating body (10), The drive mechanism (1) includes a case body (200) for housing the rotating body (10) and a circuit board (300) provided on the case body (200), and the rotational position detection device (100). Includes a light emitting element (110) and a light receiving element (120) mounted on the circuit board (300), and a light guide (130) for guiding the light of the light emitting element (110) to the light receiving element (120). The rotating body (10) is located in the light path of the light emitting element (110), and the light transmitting portion (11) provided in the rotating body (10) is accompanied with the rotation of the rotating body (10). By traversing the light path (A), The case body (200) detects a rotational position of the body (10), and the case body (200) includes a first case member (210) and a second case member (sandwiching the rotating body (10) from both sides in the rotational axis direction. 220), the circuit board (300) is provided on the first case member (210), and the light guide (130) is provided on the second case member (220). The second case member (220) is provided with a rotational position detection device (221) having a light guide insertion recess (221) for inserting the light guide (130) from the outer surface of the case body (200). 100).

  The invention described in claim 2 of the present application is that, in claim 1, the light guide body (130) has a contour shape viewed from the insertion direction into the light guide body insertion recess (221) and the reverse of the insertion direction. This is a rotational position detection device having a configuration that does not match the contour shape seen from the side.

  According to the third aspect of the present invention, in the first or second aspect, the second case member (220) is covered with the light guide (130) inserted into the light guide insertion recess (221). This is a rotational position detection device (100) having a configuration provided with a light shielding member (222).

  According to a fourth aspect of the present invention, in the third aspect, the light shielding member (222) is a plate-like or seal-like member, and the light guide is inserted into the second case member (220). The rotational position detection device (100) is configured to have a light shielding member mounting recess (223) that surrounds the entire recess (221).

  According to the present invention, it is possible to obtain a highly reliable rotational position detection device that is configured more rationally.

It is a front view which shows the movement of a timepiece according to the Example of this invention. It is a back view which shows the movement of the timepiece concerning the Example of this invention. It is a side view which shows the movement of a timepiece according to the Example of this invention. FIG. 4 is a side sectional view showing the inside of the movement of the watch according to the embodiment of the present invention. FIG. 5 is an enlarged view of a main part of FIG. 4 according to the embodiment of the present invention, and is an explanatory view showing a rotational position detection device. 1 is an exploded perspective view (front side) showing a movement of a timepiece according to an embodiment of the present invention. FIG. 4 is an exploded perspective view (back side) showing a movement of a timepiece according to the embodiment of the present invention. It is a rear view which shows the circuit board concerning the Example of this invention. It is a front view which concerns on the Example of this invention and shows a case body. It is a perspective view (front side) which shows the principal part of a light guide, a shielding member, and a 2nd case member concerning the Example of this invention. It is a perspective view (back side) which shows the principal part of a light guide, a shielding member, and a 2nd case member concerning the Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. A driving mechanism 1 shown in FIGS. 1 to 11 is an analog timepiece movement for driving hands. The drive mechanism 1 includes a motor, a speed reduction mechanism including a gear train connected to the motor, a pointer pipe for mounting the pointer, a case body 200 for storing them, and a circuit board 300 for controlling the motor. Is. The pointer pipe is driven to rotate at a predetermined speed by a motor via a speed reduction mechanism. The indicator pipe includes a minute hand pipe for attaching a minute hand and an hour hand pipe for attaching an hour hand. The hour hand pipe follows the minute hand pipe through the minute wheel.

  The rotational position detection device 100 of this example is provided in the drive mechanism 1 that rotates the rotating body 10 and detects the rotational position of the rotating body 10. The rotating body 10 to be detected is not particularly limited, but in this example, is a gear portion provided at the proximal end portion of the minute hand pipe and a gear portion provided at the proximal end portion of the hour hand pipe.

  The rotational position detection apparatus 100 includes a light emitting element 110 and a light receiving element 120 mounted on a circuit board 300, and a light guide 130 that guides light from the light emitting element 110 to the light receiving element 120. Each rotating body 10 is a light emitting element. 110, each light transmitting portion 11 provided in each rotating body 10 crosses the light path A along with the rotation of the rotating body 10, whereby each rotating body 10 is located. The rotation position is detected. The light emitting element 110 and the light receiving element 120 are arranged on one side with respect to the rotating body 10. The positions of the minute hand and hour hand are detected from the detection pattern of the light receiving element 120.

  The case body 200 includes a first case member 210 and a second case member 220 that sandwich the rotating body 10 from both sides in the rotation axis direction. The first case member 210 and the second case member 220 are injection molded members having a predetermined shape. The circuit board 300 is provided on the first case member 210, and the light guide 130 is provided on the second case member 220.

  The illustrated case body 200 is a flat type formed by assembling the first case member 210 on the front side and the second case member 220 on the back side in the thickness direction. A motor, a speed reduction mechanism, and a proximal end portion of a pointer pipe are accommodated. The first case member 210 and the second case member 220 are snapped or screwed together. The circuit board 300 is provided on a surface that is the outside (front side) of the case body 200. Specifically, the first case member 210 is screwed on the front side. The tip of the pointer pipe protrudes from the first case member 210 toward the front, and the circuit board 300 is provided with a hole through which the tip of the pointer pipe is inserted.

  The first case member 210 is provided with a light emitting element insertion concave portion 211 and a light receiving element insertion concave portion 212 into which the light emitting element 110 and the light receiving element 120 are inserted from the surface which is the outside (front side) of the case body 200, respectively.

  The second case member 220 includes a light guide body insertion recess 221 into which the light guide body 130 is inserted from the outer (back side) surface of the case body 200, and a light guide body inserted into the light guide body insertion recess 221. A light shielding member 222 covering 130 is provided. The light guide 130 is press-fitted into the light guide insertion recess 221. The light guide 130 reflects light incident from one part at a pair of end surfaces and emits light from the other part. The light shielding member 222 is a plate-like or seal-like member, and the second case member 220 is provided with a light shielding member mounting recess 223 that surrounds the entire light guide insertion recess 221. The light shielding member 222 is attached by being adhered to the light shielding member mounting recess 223.

  With such a configuration, the light guide 130 can be accurately and easily assembled to the case body 200. It is also possible to inspect the light emitting element 110 and the light receiving element 120 from the outside of the case body 200 using the light guide insertion recess 221 before assembling the light guide 130.

  In particular, in the case of this example, the light guide 130 has a configuration in which the contour shape viewed from the insertion direction into the light guide insertion recess 221 does not match the contour shape viewed from the opposite side of the insertion direction. That is, if the contour shapes match, the light guide 130 may be inserted in the wrong insertion direction during manufacturing. Once the light guide 130 is inserted, it takes time to extract the light guide 130, and the member may be deformed or damaged. Therefore, in this example, the projecting piece 131 is provided at the main point of the light guide 130 to prevent such a situation in advance. The illustrated light guide 130 has a shape in which a plurality of protruding pieces 131 are provided in a rectangular shape when viewed from the insertion direction. The protrusion 131 is provided on each of two sides forming a corner. The shape of the light guide insertion recess 221 is slightly larger than the contour shape. The light guide 130 is not inserted into the light guide insertion recess 221 when the insertion direction is reversed.

  Further, at least one of the first case member 210 and the second case member 220 is provided with pipe portions 210a and 220a that protrude toward the other of them. The light path A is configured to pass through the pipe portions 210a and 220a.

  In the case of this example, the first case member 210 is provided with a first pipe portion 210 a that protrudes toward the second case member 220, and the second case member 220 protrudes toward the first case member 210. A second pipe portion 220a is provided. The first pipe part 210a and the second pipe part 220a are in contact with each other at the tip, and the light path A is configured to pass through the inside of the first pipe part 210a and the second pipe part 220a.

  The light of the light emitting element 110 that has passed through the light transmitting part 11 enters the light guide 130, is reflected twice by 90 ° at a pair of end surfaces provided on the light guide 130, and is emitted from the light guide 130. . The emitted light sequentially passes through the second pipe part 220a and the first pipe part 210a and is brought to the light receiving element 120. Note that the positional relationship between the light emitting element 110 and the light receiving element 120 can be reversed. In that case, the traveling direction of the light path A is reversed.

  According to such a configuration, the detection accuracy of the rotational position detection device 100 can be reliably improved. That is, when the light emitting element 110 and the light receiving element 120 are arranged on one side with respect to the rotating body 10, a loss occurs in the light with the reversal of the traveling direction of the light. According to this example, diffusion of light is prevented by the pipe portions 210a and 220a. Therefore, loss of light can be reduced. Further, it is possible to prevent a situation in which the light receiving element 120 directly receives the light of the light emitting element 110 or receives the light reflected inside the driving mechanism 1.

  As described above, the rotational position detection device of this example is extremely rationally configured as a device that detects the rotational position of the rotating body. In addition, it is needless to say that the configuration of each part in the present example can be appropriately changed in design within the technical scope described in the claims, and is not limited to that illustrated in the drawings.

  For example, in this example, the circuit board is provided on the outer surface of the case body, but the circuit board may be provided on the inner surface of the case body. In that case, the first pipe portion is not provided, and the tip of the second pipe portion may be configured to contact the circuit board.

  The rotational position detection device of the present invention can be suitably used as a device that is provided in a movement of an analog timepiece and detects the position of the hands.

1 Drive mechanism (analog clock movement)
DESCRIPTION OF SYMBOLS 10 Rotating body 11 Light transmission part 100 Rotation position detection apparatus 110 Light emitting element 120 Light receiving element 130 Light guide body 131 Projection piece 200 Case body 210 1st case member 210a 1st pipe part 211 Light emitting element insertion recessed part 212 Light receiving element insertion recessed part 220 1st 2 case member 220a 2nd pipe part 221 Light guide insertion recessed part 222 Light shielding member 223 Light shielding member mounting recessed part 300 Circuit board A Light path

Claims (4)

In a rotational position detection device that is provided in a drive mechanism that rotates the rotational body and detects the rotational position of the rotational body,
The drive mechanism includes a case body that houses the rotating body, and a circuit board provided in the case body,
The rotational position detection device includes a light emitting element and a light receiving element mounted on the circuit board, and a light guide that guides light of the light emitting element to the light receiving element, and the rotating body is a light path of the light emitting element. The light transmitting portion provided in the rotating body crosses the light path with the rotation of the rotating body, thereby detecting the rotational position of the rotating body,
The case body includes a first case member and a second case member that sandwich the rotating body from both sides in the rotation axis direction,
The circuit board is provided on the first case member, and the light guide is provided on the second case member.
The rotational position detecting device, wherein the second case member is provided with a light guide insertion recess for inserting the light guide from the outer surface of the case body.   The rotational position according to claim 1, wherein the light guide has a contour shape seen from an insertion direction into the light guide insertion recess and a contour shape seen from the opposite side of the insertion direction. Detection device.     The rotational position detection device according to claim 1, wherein the second case member is provided with a light shielding member that covers the light guide inserted into the light guide insert recess. The light shielding member is a plate-like or seal-like member,
4. The rotational position detecting device according to claim 3, wherein the second case member is provided with a light shielding member mounting recess surrounding the entire light guide insertion recess.

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