JPS5819868Y2 - VHF tuner fine adjustment mechanism - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fine adjustment mechanism for a VHF tuner.

Generally, the fine adjustment methods for VHF tuners are broadly classified into a bush preset method and a rotary preset method.

The former button preset type fine adjustment mechanism has a so-called fine adjustment shaft, and by rotating the fine adjustment shaft 11 times, the fine adjustment element in the tuner is adjusted to perform fine adjustment. Since the fine adjustment shaft must be rotated by the pusher 11, there is a drawback that the operation is cumbersome.

Therefore, recently, the latter rotary preset type fine adjustment mechanism, which allows fine adjustment simply by rotating the fine adjustment shaft, has been mainly adopted.

A configuration as shown in FIG. 1 has been proposed for this type of rotary preset type VHF tuner fine adjustment mechanism, but there is a problem in creating a drag force during fine adjustment rotation.

That is, 1 is a chassis, 2 is a main shaft for channel switching, and 3 is a cylindrical fine adjustment driver coaxial with the main shaft 2.
It is rotatably loosely fitted onto the main shaft 2, and its sliding in the axial direction is restricted via a retainer or the like, although not shown in the drawings.

A plurality of cams 4 (four in the embodiment shown in the drawings) having cam surfaces opposite in direction are integrally formed on the end face of the fine adjustment driver 3.

A cylindrical slide gear 5 is coaxial with the main shaft 2, and is loosely fitted onto the main shaft 2 so as to be rotatable and slidable in the axial direction.

On the end face of the slide gear 5 facing the fine adjustment driver 3, there are formed the same number of engaging pieces 6 as the cams 4 of the fine adjustment driver 3, that is, four, which can slide along the cam surface of the cam 4.
The rotation of the fine adjustment driver 3 is configured to be transmitted to the slide gear 5.

Reference numeral 7 denotes a fine adjustment spring in the form of a leaf spring interposed between the chassis 1 and the slide gear 5, which uses its elasticity to press the slide gear 5 toward the fine adjustment driver 3, thereby causing the cam 4 on the end surface of the fine adjustment driver 3 to slide. The gear 5 is elastically engaged with the engagement piece 6 on the end face.

8 is a cluster gear, and 9 is a tuning stick having a different tuning coil wound for each channel, and has a gear screw 10 for fine adjustment at its tip.

The cluster gear 8 is rotatably supported by a fine adjustment spring 7, and is normally tilted by the elastic force of the fine adjustment spring 70. At this time, the cluster gear 8 and the gear screw 10 are also disengaged.

Such a rotary preset type VHF tuner is similar to the "fine tuning device" disclosed in, for example, Japanese Utility Model Publication No. 55-28043, and its operation is performed as follows.

If a fine adjustment operation is required, the fine adjustment driver 3 is rotated in either direction.

This rotation is transmitted to the slide gear 5 through the engagement of the cam 4 and the meshing piece 6, but the transmission to the slide gear 5 first appears as movement in the axial direction, and then rotational torque is subsequently applied to the fine adjustment driver. This becomes a rotational motion and the rotation is transmitted to the cluster gear 8.

During this operation process, the cluster gear 8 is elastically press-fitted into the fine adjustment spring 7, and a braking force is generated to prevent its rotation.

This braking force naturally acts as rotation braking for the slide gear 5, so that an axial component force is generated that tends to cause the slide gear, the engagement piece 6 of the fine adjustment driver, and the cam 4 to move away from each other.

On the other hand, since the fine adjustment driver 3 is mounted at a predetermined position on the main shaft with its axial movement restricted, the slide gear 5 moves toward the chassis 1 against the fine adjustment spring 7. Deformation occurs, changing the inclination state of the cluster gear 8 supported here, and changing the inclination state of the cluster gear 8.
A fine adjustment state in which the teeth 8a and the gear screw 10 are normally engaged is obtained.

In this state, when a rotational torque of driving force is further applied to the fine adjustment driver 3, the rotational torque rotates the gear screw 10 via the slide gear 5 and the cluster gear 8.

As a result, the gear screw 10 moves back and forth within the coil of the tuning stick 9 to change its inductance.

In other words, the initial part of the rotation of the fine adjustment driver 3 is a fine adjustment preparation operation in which the slide gear 5 moves toward the chassis side and the cluster gear 8 is normally connected to the gear screw 10, and the subsequent part of the rotation is a fine adjustment operation. This will make a contribution.

This is because the stopper 11 of the fine adjustment spring 7 is on the chassis 1.
This is a fine adjustment rotation after the spring stops moving when it hits.

When the rotational torque is released from being applied to the fine adjustment driver 3 after the fine adjustment, the slide gear 5 is pushed back to its original position by the elasticity of the fine adjustment spring 7 and becomes out of synchronization.

By the way, in the above fine adjustment mechanism, the fine adjustment driver 3
The rotational torque for fine adjustment is very small.

Therefore, if the rotational torque of the fine adjustment driver 3 during fine adjustment is small, the operational feel will be lost and fine adjustment operations with a good feel cannot be performed. , the rotational torque of the fine adjustment driver 30 becomes intermittent, making it impossible to perform fine adjustment of the tuner smoothly.

On the other hand, the most important feature of this type of fine adjustment mechanism is the mechanism that allows the slide gear to slide and properly mesh the gears.

In other words, the goal is to find a mechanism that increases the resistance to rotation in the slide gear and allows free axial movement, since axial force can be obtained from the cam surface of the driver.One of these is to increase frictional force to the cluster gear. Another method is to create rotational resistance by friction between the gear bearing and the main shaft, as in the present invention, and to create a dimension that allows freedom between the gear bearing and the slide in the axial direction. The method is to make it into a relationship.

By the way, with the former method of increasing friction in the cluster gear, there is a risk that the gear will escape due to the pressure angle of the gear, causing the slide gear to spin idly, deformation of the fine adjustment spring, problems in maintaining the relative dimensions of the press-fitted part of the cluster gear, and problems in assembly. There were practical problems such as inconvenience.

Therefore, this invention provides a fine adjustment mechanism with a good operating feel by increasing the rotational torque of the fine adjustment driver during fine adjustment.The configuration of this invention will be explained below with reference to an embodiment shown in the drawings. It is as follows.

In FIGS. 2 to 4, 21 is a chassis, and 22 is a main shaft rotatably mounted on this for channel switching.

Reference numeral 23 denotes a hollow cylindrical fine adjustment driver coaxial with the main shaft 22, and although not shown in the drawing, it is loosely fitted onto the main shaft 22 so as to be freely rotatable with axial sliding being prevented by a retainer or the like. There is.

The fine adjustment driver 23 has a large-diameter cylindrical portion 24 on one side, and a plurality of cams 25, in the embodiment shown in the drawings, four cams 25 having mutually opposite cam surfaces on the end surface of the large-diameter cylindrical portion 24. It is being formed.

Reference numeral 26 denotes a gear bearing consisting of a cylindrical body having one groove 27 in the axial direction, and includes a fine adjustment driver 230 and a dog-diameter cylindrical portion 2.
4 is elastically fitted onto the main shaft 22 using the split 27.

A slide gear 28 is loosely fitted on the main shaft 22 so as to be rotatable concentrically with the fine adjustment driver 23 and slidable in the axial direction, and is formed at opposing positions on the inner peripheral surface of the slide gear. The locking piece 29 is engaged with a groove 30 provided in the axial direction of the gear bearing 26.

On the end face of the slide gear 28 facing the fine adjustment driver 23, the same number of engagement pieces 31 as the cams 25, that is, four, which can slide along the cam surface of the cam 25 are formed, and the rotation of the fine adjustment driver 23 is controlled. The structure is such that the information is transmitted to the slide gear 28.

Reference numeral 32 denotes a fine adjustment spring in the shape of a leaf spring, which is interposed between the chassis 21 and the slide gear 28, and uses its elasticity to press the slide gear 28 toward the fine adjustment driver 23, thereby increasing the force A25 on the end surface of the fine adjustment driver 23. Slide gear 2
The engagement pieces 31 on the eight end faces are elastically engaged.

33 is a cluster gear, 34 is a tuning stick having a different tuning coil wound for each channel, and has a gear screw 35 for fine adjustment at its tip.

The cluster gear 33 is rotatably held by the fine adjustment spring 32, and is normally tilted by the elastic force of the fine adjustment spring 32, and at this time the cluster gear 33 is disengaged from the gear screw 35.

The above is the configuration of this invention, and next, the fine adjustment operation according to this invention will be explained.

Fine adjustment operations using the fine adjustment device according to the present invention are performed in substantially the same manner as in the case of FIG.

However, in the case of the present invention, the driving force applied to the fine adjustment driver 23 is also transmitted to the gear bearing 26 by the engagement between the locking piece 29 of the slide gear and the groove 30 of the gear bearing.

However, this gear bearing 26 is press-fitted into the main shaft 22 and is elastically fitted to the outer peripheral surface of the main shaft, and due to its frictional force, f
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When a driving force is further applied from the fine adjustment driver 23 to the slide gear 28 that has been subjected to a braking force, a component force is generated between the cam surfaces of the fine adjustment driver and the slide gear that tends to separate in the axial direction, and the fine adjustment spring 32 resists. and slide gear 2
8 moves in a fixed position on the chassis side in the axial direction.

Here, the teeth 28a of the slide gear 28 and the cluster gear 33
The meshing of the teeth 33b of the cluster gear and the meshing of the gear screw 35 with the teeth 33a of the cluster gear become normal, resulting in a fine adjustment state.

In this state, if the driving force applied to the fine adjustment driver 23 is further increased, the frictional force between the gear bearing 26 and the main shaft 22 will no longer be able to resist it, and the gear bearing 26 itself will begin to rotate, and this rotation will simultaneously cause the slide gear 28 and the cluster gear 3 to rotate.
3 to the gear screw 35, and moves the gear screw 35 forward and backward within the tuning stick 34.

The driving force of the fine adjustment driver 23 is released by the fine adjustment spring 32.
The slide gear 28 is moved in the axial direction by the zero rebound return,
At the same time, the gear screw 35 and the cluster gear 33 are also released from meshing, returning to the original non-fine adjustment state.

These operations are performed in the same manner for both left and right rotations of the fine adjustment driver, thereby achieving fine adjustment operation.

As explained above, this invention transmits the rotation of the drive side fine adjustment driver to the driven side gear screw through elastic engagement with the cluster gear only when the slide gear is slid to a fixed position by the rotation of the fine adjustment driver. In the rotary preset VHF tuner fine adjustment mechanism,
A gear bearing is elastically fitted onto the main shaft by using a gap between the large diameter cylindrical part provided on one side of the fine adjustment driver and the main shaft, and a locking piece formed on the inner peripheral surface of the slide gear is used. Since it is engaged with the groove provided in the axial direction of the outer circumferential surface of the gear bearing, an appropriate rotational torque is applied to the fine adjustment driver during fine adjustment, which stabilizes the rotational torque of the fine adjustment driver and allows smooth fine adjustment. At the same time, it is possible to operate with a good fine-tune feel.

[Brief explanation of the drawing]

Fig. 1 is a side view of the fine adjustment mechanism of a VHF tuner which is the premise of the present invention, Fig. 2 is a side view of the fine adjustment mechanism of the VHF tuner of this invention, Fig. 3 is an enlarged half sectional view of part A in Fig. 2, Fourth
The figure is a sectional view taken along the line ■-■ in FIG. 3. 21...Chassis, 22...Main shaft, 2
3...Fine adjustment driver, 24...Large diameter cylinder section, 25...Cam, 26...Gear bearing, 27...Cut , 28...Slide gear, 29...Latching piece, 30...
Groove, 31...Meshing piece, 32...Fine adjustment spring, 33...Cluster gear, 34...
...Synchronization stick, 35...Gear screw.

Claims (1)

[Scope of utility model registration request] A main shaft for channel switching supported by the chassis, a fine adjustment driver having a cam on the end face rotatably fitted loosely at a predetermined position on the main shaft, and a slide having an engagement piece on the end face arranged to be able to slide and rotate on the main shaft. a gear, a fine adjustment spring interposed between the slide gear and the chassis;
and a rotary preset type VHF tuner comprising a cluster gear supported by the spring and transmitting the fine adjustment rotation of the fine adjustment driver transmitted by engagement between the cam and the engagement piece to the driven gear screw, wherein the fine adjustment driver is A large diameter cylindrical portion is formed on the cam side, and a gear bearing elastically fitted to the main shaft is disposed therein, and a locking piece formed on the inner surface of the slide gear is formed on the outer surface of the gear bearing. A VHF tuner fine adjustment mechanism characterized by engaging a groove along the axial direction.