JPH04263154A - Position detector - Google Patents

Abstract

PURPOSE:To obtain a position detector which has sufficient function with a small area of a pattern film attached to a movable member by a method where in a cover is provided to cover the movable member. CONSTITUTION:A sensor holder 5 in which a photosensor 7 is housed is attached to the hole 6 of the chassis 1 of a position detector and, further, a position detecting gear 2 unified with a pattern film 4 is attached to the rear of the chassis 1 so as to have a certain distance from the photosensor 7. Then a cover 8 is attached to the chassis 1 so as to have the position detecting gear 2 between the chassis and itself. With this constitution, although the necessary area of the pattern film cannot be assured if a partially cut-off member such as a semicircular gear is used as the movable member of the position detector, by providing a cover, a sufficient function can be obtained with a small area of the pattern film.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detection device used for detecting operating positions in magnetic recording and reproducing devices such as video tape recorders.

0002

2. Description of the Related Art FIG. 6 is a plan view showing a conventional position detecting device disclosed in, for example, Japanese Patent Laid-Open No. 64-89057. In the figure, 100 is a motor, 101 is a motor 100
102 is a cam gear that meshes with the worm gear 101, 103 is the center of rotation of the cam gear 102, and 104 is a cam groove provided inside the cam gear 102. 105 is an arm, 106 is an arm 105
A rotation center 107 is provided at one end of the arm 105,
The pin 109 that engages with the cam groove 104 is the position detection gear 1
This is the center of rotation of 08. In addition, 110 is the position detection gear 1
Pattern film pasted on the bottom surface of 08, 111
111b is a light-reflecting portion formed on the surface of the pattern film 110, and a is a light-reflecting portion formed on the surface of the pattern film 110. 7 is installed at a certain distance from the position detection gear 108, and includes a light emitting element 7a and a light receiving element 7b.
112 is a system controller connected between the photosensor 7 and the motor 100.

Next, the operation will be explained. motor 100
The worm gear 101 is rotated by the rotational driving force, and the arm 105 is driven. The rotation of the cam gear 102 causes the position detection gear 108 to rotate. Position detection gear 108
A pattern film 110 having light reflecting portions 111a and light non-reflecting portions 111b in a predetermined pattern is adhered to the lower surface of the device, and the pattern film 110 also rotates as the position detection gear 108 rotates.

A photosensor 7 is disposed at a predetermined distance from the pattern film 110, and the light receiving element 7b receives the light emitted from the light emitting element 7a and reflected by the light reflecting portion 111a of the pattern film 110. Therefore, the rotation of the position detection gear 108, that is, the pattern film 1
10, the photosensor 7 sends a level change signal according to the pattern formed on the pattern film 110 to the system controller 112. The system controller 112 detects the position of the drive system based on this output signal and outputs an operation signal to the motor 100.

[0005]

Since the conventional position detecting device is constructed as described above, the rotation angle of the position detecting gear can be rephrased as the angle necessary for transitioning between all operating modes. Therefore, the area of the pattern film must be at least equivalent to the rotation angle of the position detection gear necessary for detecting the operating mode. Furthermore, the size of the position detection gear must be at least the same as or larger than the pattern film, so the position detection gear becomes large.

Therefore, in order to avoid interference near the position detection gear, other members cannot be placed on the same plane as the position detection gear, so it is necessary to change the height to avoid interference or to place them on the same plane. It must be placed in a place where it will not interfere with the equipment. This poses a problem in that the device becomes large in plan or height. This invention was made to solve the above-mentioned problems, and provides a position detection device that can make the position detection gear small with a simple configuration, and further realizes the miniaturization and thinning of the device. aim at something.

[0007]

[Means for Solving the Problems] The position detection device according to the present invention has the following features: (1) a movable body for position detection, such as a gear, assembled to a drive transmission mechanism driven by a drive source such as a motor, and a light reflecting portion; A predetermined pattern consisting of a light non-reflecting portion is provided, a photosensor consisting of a light emitting element and a light receiving element is disposed facing the pattern, and the photo sensor is used to transmit light through the light reflecting portion and the light non-reflecting portion. In the position detection device that detects the position of the movable body based on a detection signal obtained from a detection signal, a cover configured to face the photosensor and configured to at least hardly reflect light is provided so that the pattern faces the photosensor. The cover acts as a light non-reflection part when the light is not in use. (2) A cover configured to easily reflect at least light is provided facing the photosensor so that the cover acts as a light reflecting section when the pattern does not face the photosensor. This is what I did. Furthermore, (3) a movable member is provided within the operating plane of the movable body, the movable member having a surface facing the photosensor that is configured to at least hardly reflect light and moves with the movement of the movable body; When the movable member is not facing the photosensor, the movable member acts as a non-light reflecting portion, and when the movable body is facing the photosensor, the movable member is moved to a position where it does not face the photosensor. It is configured to be moved. Furthermore, (4) a movable member is provided within the operating plane of the movable body, the movable member having a surface facing the photosensor that is configured to easily reflect at least light and moving with the movement of the movable body; When the movable body is not facing the photosensor, the movable member acts as a light reflecting portion, and when the movable body is facing the photosensor, the movable member is moved to a position where it does not face the photosensor. It is configured to be moved.

[0008]

[Operation] The position detecting device of the present invention detects the light reflecting portion and the non-light reflecting portion of the movable body using a photosensor consisting of a light emitting element and a light receiving element, and detects the position. The same effect is achieved, the area of the pattern film is minimized, and the size of the movable body is thereby reduced.

[0009]

[Example] Example 1. 1 is a plan view showing the configuration of a position detecting device according to a first embodiment of the present invention, FIG. 2 is a side view showing the configuration of the main parts, and FIG. 3 is a plan view showing the operating state of the position detecting device. In FIGS. 1 to 3, 1 is a chassis;
Reference numeral 2 is rotatable around a shaft 3 attached to the back surface of the chassis 1, and a fan-shaped position detection gear with gears provided on the outer periphery; 4 is provided on the surface of the position detection gear 2; A pattern film composed of a light reflecting part 4a and a light non-reflecting part 4b, 5 a sensor holder attached through a hole 6 provided in the chassis 1, and 7 a light emitting element 7a and a light receiving element 7b integrated together. This is a photosensor attached to the sensor holder 5. 8 is a cover attached to the chassis 1; 9 is a drive gear that meshes with the position detection gear 2 and transmits driving torque to the position detection gear 2; 10 is a shaft that is the center of rotation of the drive gear 9; 11 is a position A gear A meshes with the detection gear 2; 12 is a shaft that is the center of rotation of the gear A11; 13 is a joint provided inside the gear A11; 14 is a rod rotatably held at one end in the joint 13; 15 is a gear B having a gear portion on a part of its outer peripheral surface; 16 is a joint that rotatably holds the other end of the rod 14; and 17 is a shaft that is the center of rotation of the gear B15.

[0010] Here, the configuration around the sensor holder 5 will be explained. As shown in FIG. 2, the sensor holder 5 with the required number of photosensors 7 attached thereto is attached to the chassis 1 by passing through the hole 6 provided in the chassis 1 with the photosensors 7 facing the back surface of the chassis 1. . (In this embodiment, two photosensors are shown.) Furthermore, the pattern film 4 provided on the position detection gear 2 is attached at a predetermined distance from the photosensor 7 described above. On the other hand, the cover 8 is provided on the back surface of the chassis 1 facing the photosensor 7 with the position detection gear 2 and the pattern film 4 in between, and at least the surface facing the photosensor 7 is made with a glossy finish, for example, to make it difficult to reflect light. It has a matte black color.

Next, the operation will be explained. As shown in FIG. 1, the photosensor 7 is on the pattern film 4 at the start of operation. Here, the driving force of the motor (not shown) is transmitted to the drive gear 10, thereby causing the position detection gear 2 to rotate clockwise. A predetermined number of predetermined patterns are drawn on the pattern film 4 on concentric circles with the shaft 3 as the center. As the position detection gear 2 rotates, the pattern film 4 also rotates clockwise.
The light reflecting section 4a and the light non-reflecting section 4b alternately pass over the photosensor 7. If the light reflecting section 4a is positioned above the photosensor 7, the light emitted from the light emitting element 7a will be reflected by the light reflecting section 4a.
The light is reflected by the light receiving element 7b and received by the light receiving element 7b.

[0012] Furthermore, a light non-reflecting portion 4b is provided on the photosensor 7.
If the light emitting element 7a is located, the light emitted from the light emitting element 7a will not be reflected by the light non-reflecting portion 4b, and therefore will not be received by the light receiving element 7b. The photosensor 7 outputs signals corresponding to the above two light receiving states of the light receiving element 7b to a sensor controller (not shown). Therefore, a signal having the same pattern as the pattern drawn on the pattern film 4 is sent to the sensor controller. The sensor controller receives this signal, detects the operating mode of the drive mechanism, and controls the operation of the motor.

On the other hand, as the position detection gear 2 rotates, the gear A11 also rotates counterclockwise around the shaft 12. Then, the rod 14 also moves to the right in the figure, thereby causing the gear B15 to rotate counterclockwise around the shaft 17, thereby operating other driving parts (not shown). Now, as mentioned above, since the position detection gear 2 is fan-shaped, the photo sensor 7 and the pattern film 4 face each other until the rotation angle of the position detection gear 2 reaches a certain angle. As shown in FIG. 3, the pattern film 4 is no longer located on the photosensor 7. Here, by attaching the matte black cover 8 facing the photosensor 7, the light emitted from the light emitting element 7a is not reflected by the cover 8, and therefore is not received by the light receiving element 7b. Therefore, even if the pattern film 4 is not located, the light-receiving element 7b will not mistakenly receive disturbance light or receive the light emitted from the light-emitting element 7a, and the non-reflective portion 4b will not act as a photo sensor. Exactly the same signal as when positioned above 7 is output to the sensor controller. Therefore, the sensor controller will not make a mistake in the operation mode.

Example 2. In the first embodiment described above, by providing the cover 8 facing the photo sensor 7 and configured to hardly reflect light, the same state as the non-light reflecting portion 4b is formed for the light receiving element 7b. In this embodiment, by providing a cover facing the photosensor 7 and configured to easily reflect light, the same state as the light reflecting portion 4a can be formed for the light receiving element 7b, so that the same effect can be achieved. You can expect it.

Example 3. 4 is a plan view showing the configuration of a position detecting device according to a third embodiment of the present invention, and FIG. 5 is a plan view showing the operating state of the position detecting device. In FIGS. 4 and 5, reference numeral 18 is a moving member that rotates about the shaft 3 and is provided within the operating plane of the position detection gear 2, and its upper surface is configured to at least not easily reflect light. 19 is a spring that urges the moving member 18 in the clockwise direction in the figure;
0 is a stopper that prevents the moving member 18 from rotating.

Similar to the first embodiment, in the state shown in FIG. 4, if the light reflecting section 4a is located on the photosensor 7, the light emitted from the light emitting element 7a is reflected by the light reflecting section 4a and passes through the light receiving element 7b. The light is received by Moreover, if the light non-reflection part 4b is located on the photosensor 7, the light emitted from the light emitting element 7a will not be reflected by the light non-reflection part 4b, and will not be received by the light reception element 7b. In this way, the light reception mode is controlled by the state of the pattern film 4. Now, by transmitting the drive torque to the drive gear 9, the position detection gear 2 rotates in the clockwise direction. The moving member 18 is the spring 1
Since the movable member 18 is always biased clockwise by the movable member 9, the moving member 18 also rotates clockwise.

[0017] Then, a state is reached in which the photosensor 7 and the moving member 18 face each other. When the position detection gear 2 continues to rotate, the moving member 18 comes into contact with the stopper 20, and the position detection gear 2 continues to rotate further, reaching the state shown in FIG. 5. In such a state where the photosensor 7 and the moving member 18 face each other, the light emitted from the light emitting element 7a is not reflected by the moving member 18, and therefore is not received by the light receiving element 7b. Therefore, even if the pattern film 4 is not located, the light-receiving element 7b will not mistakenly receive disturbance light or receive the light emitted from the light-emitting element 7a, and the non-reflective portion 4b will not act as a photo sensor. Exactly the same signal as when positioned above 7 is output to the sensor controller. For this reason,
The sensor controller never makes a mistake in the operating mode.

Example 4. In the third embodiment, the side of the moving member 18 that moves in the same plane as the position detection gear 2 as the position detection gear 2 moves, facing the photosensor 7, is configured to at least reflect light less easily. Although the moving member 18 forms the same state as the non-reflecting portion 4b for the light receiving element 7b, in this embodiment, the moving member 18 forms the same state as the non-reflecting portion 4b.
By configuring the opposite side to easily reflect light, the movable member 18 can form the same state with the light receiving element 7b as the light reflecting portion 4a, and the same effect can be expected.

[0019]

As described above, according to the present invention, just by providing the cover, the same output signal as when the photo sensor and pattern film are positioned facing each other can be sent to the sensor controller. Therefore, the same effect can be obtained even if the area of the pattern film cannot be increased due to interference with other parts or due to miniaturization of the device, so that it is effective in making the device smaller and thinner.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of a position detection device according to a first embodiment of the present invention.

FIG. 2 is a side view showing the configuration of main parts of the position detection device according to the first embodiment of the present invention.

FIG. 3 is a plan view showing the operating state of the position detection device according to the first embodiment of the present invention.

FIG. 4 is a plan view showing the configuration of a position detection device according to a third embodiment of the present invention.

FIG. 5 is a plan view showing the operating state of a position detection device according to a third embodiment of the present invention.

FIG. 6 is a plan view showing a conventional embodiment.

[Explanation of symbols]

2 Position detection gear 4 Pattern film 4a Light reflecting part 4b Non-light reflective part 7 Photo sensor 7a　Light emitting element 7b Photo receiving element 8 Cover 18 Moving member

Claims (4)

[Claims] 1. A movable body for position detection, such as a gear, assembled to a drive transmission mechanism driven by a drive source such as a motor, is provided with a predetermined pattern consisting of a light reflecting part and a light non-reflecting part, and the pattern is A photo sensor consisting of a light emitting element and a light receiving element is disposed facing each other, and the position of the movable body is detected by the photo sensor using a detection signal obtained through the light reflecting part and the light non-reflecting part. In the detection device, a cover configured to at least hardly reflect light is provided facing the photosensor so that the cover acts as a light non-reflecting part when the pattern does not face the photosensor. A position detection device characterized by: 2. A cover configured to easily reflect at least light is provided facing the photosensor, so that the cover acts as a light reflecting section when the pattern does not face the photosensor. The position detection device according to claim 1, characterized in that: 3. A movable member is provided within the operating plane of the movable body, the movable member having a surface facing the photosensor that is configured to at least hardly reflect light and moves with the movement of the movable body, and wherein the pattern is When the movable member is not facing the photosensor, the movable member acts as a non-light reflecting portion, and when the movable body is facing the photosensor, the movable member is moved to a position where it does not face the photosensor. 2. The position detecting device according to claim 1, wherein the position detecting device is configured to be moved. 4. A movable member is provided within the operating plane of the movable body, the movable member having a surface facing the photosensor that is configured to easily reflect at least light and moving with the movement of the movable body, the pattern being When the movable member is not facing the photosensor, the movable member acts as a light reflecting portion, and when the movable body is facing the photosensor, the movable member is moved to a position where it is not facing the photosensor. 2. The position detecting device according to claim 1, wherein the position detecting device is configured to force the user to move.