JPH07225999A - Rotary position detecting device - Google Patents

Abstract

PURPOSE:To promote the latitude of design for a cam groove by equipping a 2nd gear to be meshed with a 1st gear provided on a rotary position detector and a mode cam gear respectively and connecting the rotary position detector and the mode can gear to each other with the 2nd gear. CONSTITUTION:The device is equipped with the mode can gear 9 with the can groove 13 formed to be rotationally driven by a motor 1 and the rotary position detector 14 for detecting a rotary position of the gear 9 in accordance with a contact position provided opposite to this gear 9 and rotating with the gear 9. The device is also equipped with the 1st gear 11 provided on the detector 14 and the 2nd gears 8 and 10 to be meshed with the 1st gear 11 and the gear 9 respectively, and the rotary position detector 14 and the gear 9 are connected up by the 2nd gears 8 and 10. Thus, since the detector 14 and the gear 9 are connected up by the 2nd gears 8 and 10, it is not necessary to form a connecting means on the surface formed with the can groove 13 of the gears 9 and 11 opposite to the detector 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational position detecting device, and more particularly to a rotational position detecting device for detecting the rotational position of a mode cam gear.

[0002]

2. Description of the Related Art For example, as in a VHS system video tape recorder, a β system video tape recorder, an 8 mm video tape recorder, and a digital audio tape recorder, the rotational position of a mode cam gear is used to attach and detach the cassette housing and detect the tape running mode. There is a rotational position detection device that detects

FIG. 6 is a plan view showing an example of a conventional rotational position detecting device used in a digital audio tape recorder, and FIG. 7 is a side view showing an example of a conventional rotational position detecting device used in a digital audio tape recorder. Is.

In both figures, reference numeral 50 denotes a loading motor. The loading motor 50 is rotationally driven by turning on a mode switch (not shown) when a cassette is mounted in a cassette holder (not shown), for example. It The rotational driving force of the loading motor 50 is transmitted from the cylindrical worm 52 fixed to the rotating shaft 51 of the loading motor 50 to the cylindrical worm wheel 53.

The rotational driving force of the cylindrical worm wheel 53 is transmitted from a gear 54 formed coaxially with the cylindrical worm wheel 53 to a gear 55 meshing with the gear 54. The rotational driving force of the gear 55 is transmitted from the gear 56 formed coaxially with the gear 55 to the gear 57 that meshes with the gear 56. The rotational driving force of the gear 57 is transmitted from the gear 58 formed coaxially with the gear 57 to the mode cam gear 59 that meshes with the gear 58.

A coupling recess 60 and a cam groove 61 are formed on the upper surface of the mode cam gear 59. A mode cam (not shown) is engaged with the cam groove 61. The position of this mode cam differs depending on the attachment / detachment state of the cassette housing and the tape running mode.

A rotary position detector 63 is arranged above the rotary support shaft 62 of the mode cam gear 59. The rotational position detector 63 includes a printed circuit board 64, a housing 65, and a rotating portion 66. A connecting convex portion 67 is formed to project from the rotating portion 66, and the rotational position detector 63 and the mode cam gear 59 are connected by engaging the tip of the connecting convex portion 67 with the connecting concave portion 60.

As a result, when the mode cam gear 59 rotates based on the rotation of the loading motor 50, the rotating portion 6
6 rotates. A contact (not shown) made of a metal conductor is arranged on the upper surface of the rotating portion 66. Printed circuit board 6
A plurality of print patterns (not shown) are concentrically formed on the bottom surface of the switch 4. The print patterns and the contacts form a switch circuit.

The plurality of print patterns on the bottom surface of the printed circuit board 64 are formed so that the contact positions of the contact points and the plurality of print patterns are changed to change the conduction state of the plurality of print patterns. Therefore, the switch circuit detects that the conduction state of the plurality of print patterns changes according to the rotation position of the rotation unit 66, and the rotation position of the mode cam gear 59 is detected.

[0010]

However, according to the conventional rotational position detecting device described above, the mode cam gear 59 is used.
The connecting recess 60 and the cam groove 61 are formed on the upper surface of the above, and the existence of the connecting recess 60 impairs the degree of freedom in designing the cam groove 61.

The connecting recess 60 is formed by the mode cam gear 5
It was provided at a substantially central position in the radial direction of 9 with a slight clearance with respect to the connecting convex portion 67. Therefore, there is a problem that the detection positional accuracy of the rotational position of the mode cam gear 59 is deteriorated due to the backlash.

Therefore, the present invention has been made in view of the above points, and provides a rotational position detecting device in which the degree of freedom in the design of the cam groove is not impaired and the detection position accuracy is not impaired. With the goal.

[0013]

In order to solve the above problems, the present invention has the following configuration.

That is, the rotational position of the mode cam gear is determined in accordance with the position of the mode cam gear which is formed with the cam groove and is driven to rotate by the motor, and the position of the contact which is arranged so as to face the mode cam gear and rotates together with the mode cam gear. A rotational position detector including a rotational position detector for detecting; a first gear disposed in the rotational position detector;
A second gear that meshes with each of the first gear and the mode cam gear is provided, and the rotation position detector and the mode cam gear are connected by the second gear.

[0015]

According to the present invention having the above-described structure, since the rotational position detector and the mode cam gear are connected by the second gear, the connecting means is provided on the cam groove forming surface of the mode cam gear facing the rotational position detecting device. It acts so that it does not need to be formed. Further, since the second gear meshes with each of the first gear and the mode cam gear, there is no need to connect the rotation position detector and the mode cam gear at a position close to the rotation center position of the mode cam gear.

[0016]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a side view showing an embodiment of the present invention.

In both figures, 1 indicates a loading motor. The loading motor 1 is rotationally driven by turning on a mode switch (not shown) when a cassette is mounted on a cassette holder (not shown), for example. It The rotational driving force of the loading motor 1 is transmitted from the cylindrical worm 3 fixed to the rotating shaft 2 of the loading motor 1 to the cylindrical worm wheel 4.

The rotational driving force of the cylindrical worm wheel 4 is
From the gear 5 formed coaxially with the cylindrical worm wheel 4 to the gear 5 at the lower stage of the three-stage gear 6 corresponding to the second gear.
Is transmitted to the gear 7 that meshes with. The rotational driving force of the gear 7 is transmitted from a gear 8 formed coaxially with the gear 7 in the middle stage of the three-stage gear 6 to a mode cam gear 9 that meshes with the gear 8.

Further, the rotational driving force of the gear 7 is the three-stage gear 6
The gear 10 formed coaxially with the gear 7 and the gear 8 in the upper stage
The gear 1 corresponding to the first gear that meshes with the gear 10.
It is transmitted to 1.

That is, the mode cam gear 9 and the gear 11 are connected via the three-stage gear 6, and the common rotary shaft 12 is provided.
have. Therefore, it is not necessary to form a connecting recessed portion on the upper surface of the mode cam gear 9, unlike the conventional case, and only the cam groove 13 is formed on the upper surface of the mode cam gear 9.
Therefore, the degree of freedom in designing the cam groove 13 can be increased.

A mode cam (not shown) is engaged with the cam groove 13. The position of this mode cam differs depending on the attachment / detachment state of the cassette housing and the tape running mode. A rotation position detector 14 is disposed above the rotation shaft 12 of the mode cam gear 9. The rotational position detector 14 is roughly composed of the gear 11, the printed circuit board 15, and the rotating portion 16 described above.

FIG. 3 is a view showing the rotational position detector 14, FIG. 3 (A) is a plan view, and FIG. 3 (B) is a side view.
In FIG. 3, reference numeral 17 is a flexible printed wiring which is connected to the printed circuit board 15 from the outside to be conductive.

The rotating portion 16 is rotatably inserted into a hole 18 formed in the printed circuit board 15, and has a connecting portion 19 fixed to the rotating shaft 12 and a housing 20 fixed to the outside of the connecting portion 19. Composed of and. On the bottom surface of the housing 20,
A contact member 21 made of a metal conductor such as copper is provided. The gear 11 is fixed to the lower surface of the connecting portion 19 by, for example, an adhesive.

As a result, when the mode cam gear 9 is rotated based on the rotation of the loading motor 1, the gear 11 is rotated via the three-stage gear 6, so that the housing 20 is rotated. According to this, the contact member 21 also rotates.

By the way, the contact member 21 has a bent leaf spring shape having elasticity as shown in FIGS. 4 (A) and 4 (B). The terminals 21 ₁ and the members 21 ₂ and 21 ₃ are arranged in a row in the radial direction from the rotation center position.

On the other hand, on the upper surface of the printed circuit board 15, FIG.
A plurality of print patterns such as shown in the terminal 21 ₁ and 21 ₂
And 21 ₃ are formed concentrically. A switch circuit is configured by the plurality of print patterns and the contact member 21 of FIG. 4, and the switch circuit detects that the conduction mode of the plurality of print patterns changes according to the rotating position of the contact member 21, and the mode is detected. The rotational position of the cam gear 9 is detected.

For example, the terminal 21₁Is the rotation of the contact member 21.
Print pattern 15 according to position₁Do not come into contact with
Or Also, the terminal 21₂Is the rotational position of the contact member 21
Print pattern 15 according to₂Or 15₃Contact with
There are none. Furthermore, the terminal 21₃Is the contact member 21
Print pattern 15 according to the rotating position_FourContact with
I am disappointed. Print pattern 15_FourIs projected to the inner peripheral side
Protruding part 15_Five~ 15 ₈Are formed discretely.

According to the present embodiment constructed as described above, since the gear 11 of the rotational position detector 14 and the mode cam gear 9 are connected by the three-stage gear 6, only the cam groove 13 is provided on the upper surface of the mode cam gear 9. Can be formed. Therefore, the degree of freedom in designing the cam groove 13 can be increased.

Further, since the three-stage gear 6 meshes with the gear 11 and the mode cam gear 9, respectively, the rotational position detector 14 and the mode cam gear are located closer to the rotation center position than the outer peripheral position of the mode cam gear 9 as in the conventional case. It is not necessary to connect 9 and. That is, at the outer peripheral position of the mode cam gear 9 and the outer peripheral position of the gear 11, the rotational position detector 14 and the mode cam gear 9 are connected by the gears 9 and 11 meshing with the three-stage gear 6.

Therefore, even if there is backlash between both gears 9 and 11, it is possible to reduce the influence on the positional accuracy of the contact 21 arranged inside the outer peripheral positions of both gears 9 and 11. . As a result, the detection position accuracy of the rotational position of the mode cam gear 9 can be improved.

[0031]

As described above, according to the present invention, since it is not necessary to form the connecting means on the cam groove forming surface of the mode cam gear facing the rotational position detecting device, the cam groove forming surface is configured freely. Therefore, the degree of freedom in designing the cam groove can be improved. In addition, since it is not necessary to connect the rotation position detector and the mode cam gear at a position close to the rotation center position of the mode cam gear, the detection position accuracy can be reduced even if connection rattling occurs at each meshing portion of the second gear. There are features such as no

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view showing an embodiment of the present invention.

FIG. 3 is a diagram showing a rotational position detector 14.

FIG. 4 is a diagram showing a contact member 21.

FIG. 5 is a diagram showing a printed circuit board 15.

FIG. 6 is a plan view showing an example of a conventional rotational position detecting device.

FIG. 7 is a side view showing an example of a conventional rotational position detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 6 Three-step gear 9 Mode cam gear 11 Gear 13 Cam groove 14 Rotation position detector 21 Contact member

Claims (1)

[Claims] 1. A mode cam gear having a cam groove formed therein, the mode cam gear being rotationally driven by a motor, and the mode cam gear being disposed so as to face the mode cam gear. The mode corresponding to the position of a contact rotating with the mode cam gear. In a rotational position detecting device including a rotational position detector that detects a rotational position of a cam gear, a first gear disposed in the rotational position detector meshes with the first gear and the mode cam gear. Second
The rotation position detecting device is characterized in that the rotation position detector and the mode cam gear are connected by the second gear.