JPH10206107A - Rotary position detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary position detecting apparatus by which an angle of rotation outside a prescribed angle range can be detected. SOLUTION: A rotary position detecting apparatus is provided with a rotor 2 which comprises a gear part in the outer circumferential part and which is attached to a board 1 by a mounting member so as to be rotatable around guide shaft, with two sets of brushes 3, 4 which are attached integrally to the rotor 2 and which are slid on patterns formed on the board, with a first set of patterns which are formed in a concentric circle shape on the board in such a way that a digital signal is output by being brought into contact with the brushes 3 when the rotor is situated within a prescribed range and with a second set of patterns which are formed in a concentric circle shape on the board so as to change a resistance value across the brushes in an analog manner according to the angle of rotation of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary position detecting device, and more particularly to a rotary position detecting device for detecting a mechanism mode of a magnetic recording device such as a VTR.

[0002]

2. Description of the Related Art In general, the mechanism mode of a magnetic recording / reproducing apparatus such as a VTR is determined by rotating a cam gear having gears on the outer periphery for operating various levers from a driving source such as a motor via a gear train. . Therefore, in order to detect the rotation phase of the cam gear and the like in the detection of the mechanism mode, a rotary position detecting device is arranged in a part of the gear train of the mechanism.

FIG. 4 is a diagram showing an example of the configuration of such a conventional rotary position detecting device. FIG. 4A is a top view and FIG. 4B is a cross-sectional view.

The rotary position detecting device is fixed to the main chassis 5 by a tightening member 6 together with the substrate 1.
The rotor 2 has a gear portion on an outer peripheral portion, meshes with a part of a gear train (not shown) of the mechanism, and is mounted by a mounting member 8 so as to be rotatable around a guide shaft 7. A brush 3 that slides on a pattern provided on a substrate is integrally attached to the rotor 2.

FIG. 5 is a diagram for explaining the relationship between the pattern provided on the substrate 1 and the rotor.

FIG. 5A is a pattern diagram, and FIG. 5B is a diagram for explaining the rotation of the rotor.
Rotate in the CCW and CW directions from the ° position to the END position. In FIG. 5A, the outermost track of the brush is G
ND pattern, two inner tracks are SW-A, S
Each phase is composed of WB and SW-C. Position detection is performed digitally by applying a voltage V to SW-A, SW-B, and SW-C, and using a brush to determine whether each of SW-A, SW-B, and SW-C is electrically connected to GND. Determine.

FIG. 3 shows the rotation phase of the rotor (brush) and each SW.
FIG. 4 is a diagram showing an ON-OFF relationship of FIG. G of each SW in the figure
"L" when conducting with ND, non-conducting (when each SW voltage is V)
Is described as “H”. As shown in the upper part of FIG. 3, the rotation phase of the rotor can be detected in six modes by the detection device of the conventional example, but between the modes, SW-A, SW-B, and S are all used.
WC can recognize only the same mode of "H". Generally, the portion between these modes is not the mode actually used during the mode transition period of the mechanism, so that there is no hindrance to the basic operation.

[0008]

In the conventional rotary position detecting device configured as described above, when the mechanism is not in a predetermined operation mode but is shifting to another operation mode, a power supply such as a power failure occurs. If a situation occurs in which the mechanism is dropped (extracted), it is not possible to determine which mode the mechanism is in when the power is turned on again. Therefore, the mechanism mode is shifted by rotating the rotor in a certain direction, the position is determined, and then a predetermined mode shifting process is performed.

Therefore, since these processes are required, not only a recovery time is required, but also an optimum process for the recovery cannot be performed, which causes problems such as damaging the tape.

[0010]

SUMMARY OF THE INVENTION The above-mentioned problems are solved by a substrate,
A rotor rotatably mounted on the substrate, two sets of brushes fixed to the rotor and sliding on the substrate, and one set of the brushes when the rotor is within a predetermined angular range; A first pattern concentrically provided on the substrate so as to output a specific signal upon contact with the substrate; and a resistance value between the other set of the brushes continuously changed according to a rotation angle of the rotor. And a second pattern provided concentrically on the substrate so as to make it possible to solve the problem.

[0011] In addition to the conventional configuration of brushes and patterns, the rotary position detecting device of the present invention has a structure in which the resistance between the second set of brushes is continuously changed according to the rotation angle of the rotor. The concentric second pattern makes it possible to detect the rotation angle of the rotor other than when it is within a predetermined angle range, which cannot be determined by the conventional position detection device.

[0012] It is preferable that the second pattern is a pattern made of a resistor, the resistance being linearly changed in accordance with the rotation angle of the rotor.

The rotary position detecting device of the present invention can be used for detecting a mechanism mode of a magnetic recording / reproducing device.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a rotary position detecting device according to the present invention. FIG. 1 (a) is a top view and FIG. 1 (b) is a sectional view.

In the configuration of the rotary position detecting device of the present embodiment, a brush 4 is added to the configuration of the conventional example described above.
Other configurations indicated by the same reference numerals are the same as those of the conventional example, and the description is omitted.

FIG. 2 is a diagram for explaining the relationship between the pattern and the rotor according to the present embodiment.

FIG. 2A is a pattern diagram, and FIG. 2B is a diagram for explaining rotation of the rotor. In the figure, SW-
A, SW-B, SW-C, GND, and the brush 3 have the same functions as those of the above-described conventional example, and a description thereof is omitted.

In the pattern diagram of FIG.
Further, a pattern is formed by a resistor on the inner peripheral portion of one stage, and a voltage V is applied to both ends. The brush 4 provided on the rotor slides on the pattern between the pattern and the innermost peripheral portion.

Therefore, as the rotor and brush 4 rotate from the rotor rotation angle of 0 ° to END in the CCW direction in the figure, the voltage obtained at Vd has a variable resistance value due to the rotation of the rotor. It changes linearly like a graph showing the relationship with Vd. As a result, the rotation angle can be detected even during the transition to the mechanism mode.
The obtained voltage of Vd is connected to a mechanism control circuit for controlling a mechanism (not shown).

As described above, in the normal state, the rotary detection device of this embodiment has the same SW-A, S
The mechanism mode is determined based on WB and SW-C. When the mechanism is in the operation transition mode, if the power is cut off due to a power failure or the like, the pattern and the brush whose resistance value changes analogously when the power is turned on again are changed. 4, the current rotation angle is detected on the basis of the voltage Vd obtained. Thus, even when the mode is being shifted to the mode when the power is turned off, the current rotation angle can be detected. Therefore, it is possible to control the mechanism control circuit to always perform the optimal mechanism return operation in a short time when the power is turned on again to return.

In the pattern diagram of FIG. 2A, the innermost pattern may be a simple pattern having no resistance or a pattern having a variable resistance value, and is determined by a circuit connected at a subsequent stage.

[0023]

According to the rotary position detecting device of the first aspect, the resistance value between the second pattern and the sliding brush changes continuously according to the rotation angle of the rotor, thereby providing a predetermined value. It is possible to detect the rotation angle of the rotor even when the rotation angle is not within the above range.

According to the rotary position detecting device of the present invention, the resistance between the second pattern and the sliding brush changes linearly in accordance with the rotation angle of the rotor.
The rotation angle can be easily detected.

According to the third aspect of the present invention, the present rotation angle is detected after the power is turned on again, even if the magnetic recording / reproducing apparatus is in the mode when the power is turned off. can do. Therefore, when the power is turned on again and restored, the circuit for controlling the mechanism can be controlled so as to always perform the optimal restoration operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a rotary position detecting device of the present invention.

FIG. 2 is a diagram for explaining a relationship between a pattern and a rotor according to the embodiment of FIG. 1;

FIG. 3 is a diagram illustrating a relationship between a rotation angle of a rotor and a signal obtained from a pattern.

FIG. 4 is a diagram showing an example of the configuration of a conventional rotary position detection device.

FIG. 5 is a diagram for explaining a relationship between a conventional pattern and a rotor.

[Explanation of symbols]

 1 board 2 rotor 3,4 brush

Claims (3)

[Claims] 1. A substrate, a rotor rotatably mounted on the substrate, two sets of brushes fixed to the rotor and sliding on the substrate, and the rotor being within a predetermined angular range. A first pattern provided concentrically on the substrate to output a specific signal in contact with one set of the brushes and another set of the brushes according to a rotation angle of the rotor. And a second pattern provided concentrically on the substrate so as to continuously change the resistance value of the rotary position detecting device. 2. The pattern according to claim 1, wherein the second pattern is a pattern made of a resistor, the resistance of which is configured to change linearly in accordance with the rotation angle of the rotor. The rotary position detecting device as described in the above. 3. The rotary position detecting device according to claim 1, wherein the rotary position detecting device is used for detecting a mechanism mode of the magnetic recording / reproducing device.