JPS6030450B2 - Tuning device in receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tuning device in a receiver (for example, a radio receiver), and more particularly to a tuning device in which a motor drives a tuning variable capacitor.

While driving a variable capacitor for tuning of a high frequency amplifier circuit or a variable capacitor for varying the oscillation frequency of a local oscillation circuit (hereinafter collectively referred to as a variable capacitor for tuning) by a motor, the tuning state at that time is detected, and the output is used as described above. When controlling the rotation of a motor to perform automatic tuning or automatic tuning deviation correction, it is relatively easy to achieve high precision electrical processing to create a motor control signal based on the detected tuning status signal. However, the mechanical transmission system that transmits the rotation of the motor to the tuning variable capacitor has various problems in accuracy, responsiveness, operability, etc. In addition, in the case of a tuning device in a receiver that can drive the tuning mechanism from either the rotational force applied from the tuning knob or the rotational force applied from the motor, When the tuning mechanism is driven by the rotational force, the tuning knob also rotates at the same time, which may cause surrounding objects to get caught in the tuning knob or children's fingers to be caught. In addition, it is aesthetically undesirable for the tuning knob to rotate by itself, and if there is a load with large inertia such as a flywheel on the tuning knob, an extra load will be placed on the motor, preventing overrun. Therefore, there were problems such as the need to increase the size of the motor or install a special brake. This invention was made to solve the above-mentioned problems in the mechanical transmission system, and is a tuning device for a receiver that has excellent accuracy, responsiveness, and operability, and has a simple structure and can be manufactured at low cost. It provides:

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

FIG. 1 is a front view of a radio receiver to which the present invention is applied, and FIG. 2 is a plan view showing the radio receiver with its top surface opened.

As shown in FIG. 1, the front panel 2 of the radio receiver 1 includes a rotary knob 3 for tuning, which also serves as a touch switch contact part, a rotary knob 4 for volume adjustment, a power-on push button 5, and a function push button. 6a to 6e, tuning meter 7,
A detection output meter 8, a dial display section 9, etc. are provided, and the dial display section 9 is also provided with preset channel selection push buttons 10a to 10h.

On the other hand, in the dial display section 9, a pointer member 13 having a pointer 12 displayed thereon is slidably attached to a guide bar 11 extending along the longitudinal direction, as shown in FIG.
3 is pulled by a dial rope 14. This dial rope 14 is stretched in a loop shape via a dial pulley 16 attached to the main chassis 15, and is sequentially fed left and right as the rope drive pulley rotates, which will be described later. be done.

Reference numeral 17 denotes a multiple variable IJ converter in a high frequency amplifier circuit and a local oscillation circuit which will be described later. This multiple variable converter 17 is rotated by a dial rope 14 via a variable converter pulley 18.

On the other hand, 19 is a flywheel that rotates integrally with the channel selection droplet 3, 2 is a variable capacitor drive motor which will be described later, 21 is a clutch plate that is selectively pressed into contact with the flywheel 19 and variable capacitor drive motor 20, and 22 is a A rope drive pulley 23 rotates together with the clutch plate 21, and 23 is a solenoid plunger that drives the clutch plate 21 to separate.These will be explained in detail below with reference to FIGS. 3 to 8.

In FIG. 6, reference numeral 24 denotes a wheel bearing fixed to the sub-chassis, which will be described later.This wheel bearing 24 is made of a non-conductive synthetic resin material.
A wheel shaft 25 is rotatably inserted into the wheel 4.

A wheel bush 27 is fixed to this wheel shaft 25 via a screw 26, a flywheel 19 is integrally fixed to this wheel bush 27, and furthermore, a selected legitimate child 3 is fixed to the wheel shaft 25. A dial shaft 28 for fixing is fixed with iron. Therefore, the dial shaft 28 and the flywheel 19 rotate integrally. Further, a clutch bush 29 made of yellow steel or the like is inserted into the wheel shaft 25 so that it can freely rotate and slide in the axial direction, and the rope drive pulley 22 is fixed to this clutch bush 29 by screws 30'. In addition, a clutch plate support disk 31 made of synthetic resin such as acetal copolymer is integrally fixed to the clutch bush 29.

A non-slip layer 32 made of a material with a high coefficient of friction such as chloroprene rubber is coated on the green outer periphery of the clutch plate support disk 31, and as will be described later, it provides sufficient friction when it comes into pressure contact with the flywheel 19. This is how the clutch plate 21 is constructed. Therefore, when the dial shaft 28 is rotated with the clutch plate 21 and the flywheel 19 in direct contact, the rope drive pulley 22 is integrally connected to the dial shaft 28 via the clutch plate support disk 31 and the clutch bush 29. It will rotate to . On the other hand, as shown in FIG. 2, a sub-chassis 33 is fixed horizontally within the main chassis 15, and the wheel bearings 24,
Variable capacitor drive motor 20 and solenoid plunger 2
The war calendar of the 3rd class is integrally fixed on this sub-chassis 33.

That is, as shown in FIGS. 3 to 5, the wheel bearing 24 is made of a non-conductive material and is inserted into the ratchet insertion hole 34 formed in the vertical bent portion 33a of the sub-chassis 33. While inserting the threaded portion 24a, a ring 35 made of an insulating material (hereinafter referred to as an insulating ring) and a washer 36 are stacked in this order from the other side.
A detection terminal 37 of a touch switch, which will be described later, protrudes from 6, and is fixed by tightening a nut 38 from above. On the other hand, the channel selection droplet 3 fixedly fixed to the dial shaft 28 is made of a conductive material such as metal, for example, aluminum. It is electrically conductive to the detection terminal 37 of the touch switch.

Further, the detection terminal 37 of the touch switch is insulated from the sub-chassis 33 by a non-conductive wheel bearing 24 and an insulating ring 35. Therefore, the touch switch operates only when the channel selection legitimate child 3 is touched. As shown in FIG. 2, FIG. 3, and FIG. 5, a solenoid plunger 23 is fixed to the raised rear stage of the sub-chassis 33, and the tip of the plunger iron core 23a of the solenoid plunger 23 is is L as shown in Figure 8.
The clutch lever 39 made of synthetic resin is connected to the screw 4.
0' Trowel is fixed.

Between the spring locking hole 42 drilled in the plunger side end of the clutch lever 39 and the spring locking piece 43 formed by vertically bending the sub-chassis 33,
A coil spring 44 for drawing out the plunger is tensioned, so that the plunger iron core 23a is biased in the drawing direction when the solenoid plunger 23 is not energized.
On the other hand, a rectangular hole 41 having four rounded corners is bored in the seat portion 39a formed at the other end of the clutch lever 39, and the clutch bush 29 is rotated in this rectangular hole 41. They will be able to play together freely.

Moreover, especially in the state where the plunger 23a protrudes,
Rope drive pulley 22 and clutch lever 39 seat portion 3
It is set so that a gap S is created between it and 9a.
It is configured so that the load at the initial stage of the retracting operation of the plunger 23a can be reduced as much as possible when the solenoid is energized, which will be described later. As shown in FIGS. 2 to 4, a motor support piece 45 having an L-shaped cross section is mounted on the sub-chassis 33.
is attached to this motor support piece 45, and the axis of the motor 20' for driving the converter is parallel to the clutch plate 21, and as shown in FIG. Push 46 and washer 4
It is fixed with a screw 48 via 7.

Therefore, as will be described later, when the clutch plate 21 hits the rotating shaft 20a of the motor 20 in conjunction with the retracting operation of the solenoid plunger 23, the elastic bushing 46 retracts appropriately while resisting the force received from the clutch plate 21. As a result, the pulling margin of the plunger 23a is secured, and the rotating shaft of the motor 20 and the clutch plate 21 come into contact with each other with appropriate elasticity.Furthermore, vibrations generated by the motor 20 are also absorbed by the elastic bushing 46, reducing noise. Occurrence is prevented. It also absorbs load changes on the motor shaft and suppresses uneven rotation. Further, as shown in FIG. 7, the rotating shaft 20a of the motor 20 is covered with a cap 49 made of a material with a high friction coefficient, such as urethane rubber or chloroprene, to ensure that the rotation of the motor 20 is transmitted to the clutch plate 21. It is configured so that it can be done. Thus, during manual channel selection, that is, when the solenoid plunger 23 is in a de-energized state, the clutch plate 21 is elastically pressed against the flywheel 19 by the force applied from the spring 44 via the clutch lever 39. , dial shaft 28, wheel shaft 25, wheel shaft 27
The rotational force of the selection heir 3 is transmitted to the flywheel 19 via the friction force between the clutch plate 21 and the flywheel 19, and is also transmitted to the clutch plate 21 via the clutch bush 29 to the rope drive. The rotation is transmitted to the pulley 22, and the rotation is further transmitted to the dial rope 14.
The signal is transmitted to the variable comparator pulley 18 via the variable capacitor 18, and the tuning variable capacitor 17 is driven. On the other hand, during automatic channel selection, that is, when the solenoid plunger 23 is energized, the electromagnetic force applied via the clutch lever 39 pulls the clutch plate 21 away from the flywheel 19, and conversely, the rotation of the motor 20 It is elastically pressed against the shaft 20a.

As a result, the rotational force of the motor 20 is transmitted to the clutch plate 21 via the frictional force between the cap 49 and the clutch plate 21, and the tuning variable capacitor 17 is driven in the same manner as described above. At this time, the power transmission system from the tuning knob 3 to the flywheel 19 (first power transmission system) and the power transmission system consisting of the motor 20 (second power transmission system) are completely mechanically separated. Since they are constructed independently, no forces act between the two transmission systems, which means that both transmission systems can rotate freely relative to each other. Therefore, as in this embodiment, the first power transmission system includes a flywheel 19 having a large inertia, or the wheel bearing 24
Even if a frictional force occurs between the wheel shaft 25 and the like, if the clutch plate 21 is connected to the motor 20 side, all of the above inertial force and frictional force will be transferred to the motor that constitutes the second power transmission system. Therefore, when the motor 20' starts rotating, the inertia force and frictional force of the flywheel 19 may overload the motor 20', impairing its operational response, or when the motor 20 stops. There is no fear that the motor 20 will overrun due to the inertial force of the flywheel 19, and the accuracy, responsiveness, etc. of this type of variable capacitor drive system can be significantly improved. There is also a visual and design effect in that the tuning knob 3 does not rotate inside.

FIG. 9 is a block diagram showing the electrical configuration of the radio receiver 1 described above. In this figure, for example, FM broadcast waves input to the antenna 50 are amplified by a high frequency amplification circuit 51, and then localized by a radio frequency amplifier circuit 52. The intermediate frequency signal obtained by mixing with the local oscillation output from the oscillation circuit 53 is amplified by the intermediate frequency amplification circuit 54 and then demodulated via the FM detection circuit 55 and the demodulation circuit 56.

Reference numerals 17a and 17b denote variable capacitors constituting the multi-variable capacitor 17. The variable capacitor 17a is used to change the tuning frequency limit s of the high frequency amplifier circuit 51, and the variable capacitor 17b is used to change the frequency limit L of the local oscillation circuit 53. used. 57 is preset with a numerical value corresponding to the intermediate frequency iP, and then outputs the local oscillation output for a predetermined period of time (for example,
Count every 10-5 seconds), and measure 100 iP = 100 seconds.
Numeric value (BCD coded value) signal S of KHz or higher
, and 58 is a frequency display that displays the output of the counter 57.

59 is configured to memorize a numerical signal S corresponding to the frequency of each broadcast station by giving a write control signal and an address designation signal each time the receiver is completely tuned to a plurality of broadcast stations in advance. memory.

6. The memory 5 by providing a write control signal
9 is stored, and one-shot pulses outputted from the waveform shaping circuit 62 each time the pushbutton switch 61 for manual electronic tuning is pressed, or when the switch 63 for automatic electronic tuning is turned on. The counter is configured to count the output blocks of the oscillation circuit 65 that are supplied via the gate circuit 64, and the gate circuit 64 is configured to close upon receiving the output of the tuning detection circuit 66 which is generated when the tuning is completed. has been done.

Reference numeral 67 is a so-called charge pump type digital comparator, which performs digital calculation (subtraction) on the BCD signal S supplied from the counter 57 and the BCD signal S2 supplied from the counter 60, and corresponds to the result of this calculation. The control voltage that was holding the DC voltage at that time (DC voltage)
, and outputs the control voltage Vc obtained by this subtraction.

When the gate circuit 68 is opened, this control voltage Vc is supplied to the switching transistor 71 via the plunger drive circuit 69, thereby energizing the solenoid plunger 23 and driving the motor. Motor 20 rotates via circuit 70. On the other hand, the gate circuit 68 is configured to be closed by the output (touch output) of the contact detection circuit 72 obtained when a part of the human body, such as a fingertip, touches the channel selection legitimate child 3.

The presence or absence of a human body's contact with the tuning knob 3 is detected via the detection terminal 37 electrically connected to the dial shaft 28, as described above. Thus, the function pushbuttons 6a to 6e or the preset pushbuttons 10a to 10 arranged on the front panel 2 shown in FIG.
h as necessary, selectively turn on and off the manual electronic channel selection pushbutton switch 61 and the automatic electronic channel selection switch 63 shown in FIG. 9, or give an address designation signal to the memory 59. At the same time, when a write control signal is given to the counter 60, the digital comparator 67 outputs a control voltage Vc corresponding to the difference between the frequency selected at that time and the desired frequency, and this control voltage Vc
In response, the solenoid plunger 23 is energized, the clutch plate 21 is pressed against the rotating shaft 20a of the motor 20, and at the same time, the control voltage Vc is supplied to the motor 20 via the motor drive circuit 70. The motor 20 rotates.

This rotational force is transmitted to the rope drive pulley 22 via the clutch plate 21 to tension and drive the dial rope 14, and the tensile force is transmitted via the variable comparator pulley 18 to the multiple variable capacitor 17 for tuning. As a result, the tuning variable capacitor 17a built into the high frequency amplifier circuit 51 and the frequency variable variable capacitor 17b built into the local oscillation circuit 53 rotate to perform a desired tuning operation. In the case of preset tuning and manual electronic tuning, the motor 20 stops when the value corresponding to the preset desired frequency on the counter 60' matches the counted value on the counter 57, and the automatic electronic In the case of tuning, the counter 60 stops advancing when synchronization with one of the broadcast frequencies is achieved, and at the same time, the two motors also stop. On the other hand, when the selection knob 3 is pinched with a fingertip in order to switch to manual selection using the channel selection legitimate child 3 during the above-mentioned electronic tuning, the contact detection circuit 72 is activated and the gate circuit 68 is closed by its output. , the power to the solenoid plunger 23 is cut off, and the motor 2
0 is also cut off, and as a result, the clutch plate 21 is pressed against the flywheel 19 by the force of the spring 44, and the rotational force of the tuning knob 3 is transmitted to the tuning variable capacitor 17 as described above. It turns out.

In other words, even during electronic tuning by motor drive,
It is possible to switch to manual channel selection by simply touching the channel selection heir 3 without any special switching operation, which greatly simplifies the operation. FIG. 10 is a block diagram showing yet another example of the electrical configuration of this radio receiver, and the feature of this circuit is that the detection output of the FM detection circuit 55 is introduced into the AFC (automatic frequency control) circuit 73. A frequency correction signal is obtained and applied to the local oscillation circuit 53 via the gate circuit 74 to automatically correct tuning deviations due to fluctuations in the local oscillation frequency. configured to be closed by the output of the contact detection circuit 72,
This allows AF to be selected during manual channel selection using channel selection knob 3.
The C circuit 73 is turned FF to eliminate fluctuations in the local oscillation frequency due to the influence of the AFC circuit 73, making it possible to more sharply find the tuning point.

Further, in this embodiment, an analog comparator 75 is used in place of the digital comparator 67,
F/V is connected to the output side of the local oscillation circuit 53 and memory 59.
A conversion circuit 76 and a D/A conversion circuit 77 are provided to achieve analog comparison processing. In this example, the configuration for automatic and manual electronic tuning is omitted, but this is achieved by, for example, a D on the output side of the counter 60 shown in FIG.
It will be easily understood that what is necessary is to provide a /A conversion circuit.

As is clear from the above description, the tuning device according to the present invention has a first power transmission shaft that transmits the rotational force applied from the tuning knob, and a second power transmission shaft that transmits the rotational force applied from the motor. power transmission shafts are provided facing each other with their respective terminal ends abutted against each other and are mechanically separated from each other, and a power transmission shaft is provided between each terminal end of the two transmission shafts that can be selectively connected to each terminal end. A bidirectional clutch mechanism is provided, and a switching control means for controlling switching of the bidirectional clutch mechanism is provided, and the tuning mechanism is driven by the power taken out from the bidirectional clutch mechanism, The switching control means is constituted by a touch switch circuit that is activated by contact with the channel selection eldest child and uses its output to switch and connect the clutch mechanism to the first power transmission shaft. The second power transmission shaft can rotate freely without affecting each other, so when manually selecting a channel using the channel selection knob, there is no influence from the second power transmission system including the motor. It is possible to smoothly rotate the channel selection heir without being influenced by it at all, and conversely, in the case of electronic tuning using a motor, the motor can be rotated without being affected by the first power transmission system including the station knob. It can be rotated with as light a load as possible, and when switching from automatic or manual electronic tuning or preset tuning where the tuning variable capacitor is driven by the motor to manual tuning using the tuning knob, All you have to do is touch the tuning knob with your fingertips, and there is no need for any special sliding operation, which can significantly improve the accuracy, responsiveness, and operability of a tuning device using this type of motor. .

In addition, especially in the case where the flywheel is attached to the first power transmission system so as to rotate together with the selected heir as in the embodiment, the first and second power transmission systems may be configured to be mechanically separated. This prevents the inertia of the flywheel from overloading the motor when it starts, impairing the responsiveness of the tuning operation, or, for similar reasons, overrunning the motor when it stops, causing tuning errors. In addition to the remarkable device-specific effects, there is also the visual and design effect that the tuning knob does not rotate during the tuning operation by the motor.

[Brief explanation of the drawing]

FIG. 1 is a front view of a radio receiver to which this invention is applied;
Fig. 2 is a plan view showing the radio receiver with the front upper surface open; Fig. 3 is a plan view showing the motor, clutch mechanism, etc. installed on the sub-chassis; Fig. 4 is a partially cutaway view of the same part. Figure 5 is a front view, Figure 5 is a side view, Figure 6 is a half-cut sectional view showing main parts around the flywheel and clutch mechanism, Figure 7 is a sectional view showing the motor mounting structure, and Figure 8 is a clutch lever. FIG. 9 is a block diagram showing an example of the electrical configuration of the radio receiver, and FIG. 10 is a block diagram showing another example. 1... Receiver, 3... Tuning legitimate child, 17, 17a
, 17b... Tuning variable capacitor, 28, 25, 2
7, 19...First power transmission system, 20a, 49
...Second power transmission system, 21, 23, 39, 44.
...Clutch mechanism, 3, 72, 68, 69, 71...
...Switching control means, 3,72...Touch switch circuit. Figure 3 Figure 4 Figure 5 Ship diagram N Rudder Figure 6 Figure 7 Figure 8 Sphere diagram 〇 Ship

Claims (1)

[Scope of Claims] 1. A first power transmission shaft that transmits the rotational force applied from the tuning knob and a second power transmission shaft that transmits the rotational force applied from the motor, each end of which is connected to the other. They are placed facing each other and mechanically separated from each other, and:
A bidirectional clutch mechanism is provided between each terminal end of the two transmission shafts, and the bidirectional clutch mechanism is selectively connectable to each terminal end; Further, a switching control means for controlling switching of the bidirectional clutch mechanism is provided:
The tuning mechanism is driven by the power taken out from the two-way clutch mechanism, and the switching control means is operated by contact with the tuning knob, and the switching control means operates by contacting the tuning knob, and uses its output to drive the tuning mechanism. 1. A tuning device for a receiver, comprising a touch switch circuit for selectively connecting a clutch mechanism to the first power transmission shaft. 2. The tuning device in a receiver according to claim 1, wherein the tuning device is configured to turn off an AFC circuit for correcting tuning deviation by the output of the touch switch circuit.