JPH08122450A - Viscous coupling gear - Google Patents

Abstract

PURPOSE: To obtain a thin and compact viscous coupling gear employing a stepping motor as a drive source in which the second hand wheel performs a substantially smooth continuous rotational motion. CONSTITUTION: The disc part 11a of a fourth gear 11 is provided, on one side thereof, with a tubular wall part 11b projecting therefrom. The wall part 11b is provided with a pinion 11c and a recess 11d, respectively, on the outside and inside thereof and the recess 11d is idly fitted with a protrusion 2a formed on an upper base plate 2 located on the wall part side. A gap part C between the recess 11d and the protrusion 2a is filled with a viscous fluid 12. A groove part 2b for receiving the viscous fluid 12 flowing out of the gap part C is made closely and oppositely thereto at the root of the upper base plate 2 where the protrusion 2a is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscous coupling gear device, and more particularly, to a viscous coupling which uses a step motor as a drive source and causes a second hand wheel to make a substantially smooth continuous rotary motion. The present invention relates to a gear device.

[0002]

2. Description of the Related Art A timepiece mechanical body of a quartz timepiece transmits rotation of a drive motor to a second hand wheel through a train wheel and rotates the second hand wheel. Usually, the second hand wheel is decelerated to rotate a minute hand wheel. , It has a mechanism to further reduce the speed and rotate the hour wheel. As the drive motor, a step motor with extremely low battery consumption is used. Since the step motor makes intermittent rotary motion, the second hand wheel also makes intermittent motion at 1 second intervals.

With respect to the movement of the second hand wheel, there are some voices of consumers who desire a sweep movement in which the hands continuously display the flow of time.

A sweep motor is generally used as a means for realizing such a sweep motion, but it has drawbacks that the manufacturing cost of the motor is high and the battery consumption is high. For this reason, it has been practiced to provide a motion converting means for converting the intermittent rotary motion of the step motor into a continuous rotary motion. Several proposals have been made for providing a continuous rotating motion to the second hand wheel of a timepiece machine body having a step motor as a drive source by providing such a motion converting means (for example, the actual flat plate 2-. 128994).

According to the above proposal, the rotation of the step motor is transmitted to the gear fixed to the bush loosely fitted to the second hand shaft through the train wheel, and the motion converting means provided in the rotation transmission path after the bush is transmitted. By adopting a configuration that gives continuous rotation to the second hand axis. As the motion converting means, as a first means, a disc positioned so as to surround the bush is provided above the bush loosely fitted to the second hand shaft so as to rotate integrally with the second hand shaft, and the bush and the disc are separated from each other. The gaps are connected by a spiral spring so that changes in speed due to intermittent motion can be absorbed.

As a second means, a plate-like member is loosely fitted to the tip of the second hand shaft, and the disc and the plate-like member are connected by a spring member so that the plate-like member can be driven by the disc. Thus, the speed difference due to the intermittent motion is absorbed. Further, as a third means, the above-mentioned plate-like member is housed in a container in a hermetically sealed manner, and a viscous fluid such as lubricating oil is filled in the container to prevent the viscous resistance of the plate-like member from rotating in the viscous fluid. Upon generation, the second hand shaft is allowed to make smooth continuous rotational movement.

In addition to the above technique, as a second conventional technique, there is a first means for elastically coupling a gear and a pinion by a coil spring in a train wheel for transmitting the rotation of a step motor to a second hand wheel, and a main plate and a gear. There is one in which the second hand shaft is provided with a protruding portion on one side and a concave portion on the other side so as to be loosely fitted, and a second means for providing a viscous fluid in the gap between the protruding portion and the concave portion is provided to make the second hand shaft a smooth continuous rotational movement. .

[0008]

SUMMARY OF THE INVENTION In the above-mentioned first prior art, the second hand wheel is made to rotate continuously by absorbing the discontinuity of the speed by the triple means of the intermittent motion of the step motor. Is. However, since all of these motion converting means are laminated in the axial direction of the second hand shaft, there is a problem that the timepiece mechanical body becomes thick. Second
In the prior art of, in order to prevent the viscous fluid provided in the gap from adhering to the teeth of the gear and becoming a load when flowing out,
There is a problem that miniaturization is difficult because the teeth have to be sufficiently separated from the gap.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact and thin viscous coupling gear device that uses a step motor as a drive source and allows a second hand wheel to make a substantially smooth continuous rotary motion.

[0010]

In order to achieve the above object, the viscous coupling gear device of the present invention has a protrusion on one of a gear and a ground plate viscously coupled to the gear,
The other side is provided with a recess into which the protrusion is loosely fitted, and a viscous fluid is provided in a gap between the recess and the protrusion, and the other of the protrusions is provided. A groove portion is provided at a base portion of the protrusion to accommodate the viscous fluid flowing out from the gap portion so as to closely face the gap portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a base plate 1 and an upper base plate 2 as an example of a base plate face each other, and an intermediate plate 3 is provided in parallel between them. A well-known step motor (not shown) and a rotor 4 which is intermittently rotated by this step motor are provided through a shaft portion and a bearing hole portion respectively formed in the base plate 1, the upper base plate 2, and the middle plate 3. A reduction gear train R for transmitting the rotation to a second hand wheel 13 described later is provided.

A magnet 4a is attached to the rotor 4. In the rotor 4, both ends of a rotor shaft 4b are pivotally supported by a base plate 1 and an upper base plate 2, and a rotor pinion 4c integrally formed with the rotor shaft 4b meshes with a drive wheel 5. The pinion portion 5a of the driving vehicle is the third gear 7 of the third wheel 6 described later.
Meshes with.

The third wheel & pinion 6 includes a third wheel 7 and an intermediate gear 10 coaxially rotatably supported by a shaft 7a of the third wheel 7.
A disk 8 provided below the intermediate gear so as to face the intermediate gear, and a coil spring 9 coaxially provided on the shaft 7a of the third gear so as to transmit a rotational force from the disk to the intermediate gear 10. It is composed of and. The disk 8 is press-fitted onto the shaft 7a of the 3rd gear and rotates integrally with the 3rd wheel 6.

Both ends of the coil spring 9 have a disk 8 and an intermediate gear 1.
When the disk 8 rotates, the coil spring 9 is wound and tightened to absorb the torque received from the disk 8 and apply the rotational torque to the intermediate gear 10. 3
As a means for preventing the coil spring 9 from being excessively tightened or unwound and damaged when an unexpected load is applied to the wheel 6 side, the engaging protrusion 10a is fitted to the intermediate gear 10.
Is formed, and an engaging protrusion 8a is formed on the outer periphery of the disk 8. When a force equal to or larger than the allowable value is applied to the coil spring 9, the engagement protrusion 10a comes into contact with the engagement protrusion 8a so that the coil spring 9 is not excessively tightened or unwound.

The intermediate gear 10 meshes with the fourth gear 11. A cylindrical wall portion 11b is projected from one side of the disk portion 11a of the No. 4 gear 11, and a can 11c is provided outside the wall portion 11b and a recess 11d is provided inside. A wall-shaped projection 2a formed on the upper base plate 2 located on the wall side is loosely fitted in the recess 11d. A viscous fluid 12 such as grease that applies a load of viscous resistance to the second hand wheel 13 is placed in a gap C between the recess 11d and the protrusion 2a. The recessed portion 11d also has a function of preventing sink marks at the time of molding the disk portion 11a of the fourth gear 11, and a means for applying a load of viscous resistance is configured by utilizing this. 4th gear 1
The hole 11e provided in the central portion of 1 is fitted to the protruding shaft 1a provided in the base plate 1.

The pinion 11c of the fourth gear 11 is a second hand wheel 13
Is meshed with the second hand gear 13a that is integral with. Viscous fluid 12
Has a function of absorbing a rotational speed change accompanied by intermittentness transmitted from the third wheel & pinion 6 by viscous force. For this reason,
The change in the rotational speed that remains even after being absorbed by the coil spring 9 provided in the third wheel 6 is further buffered by the viscous fluid 12, and the second hand wheel 13 makes a substantially smooth continuous rotational movement. .

As shown in FIG. 2, a groove 2b for accommodating the viscous fluid 12 flowing out from the gap C is provided at the root of the upper base plate 2 where the protrusion 2a is formed so as to closely face the gap C. There is. The outer edge E of the groove 2b faces the top T of the wall 11b, and the opening width W of the groove 2b is formed to be wider than the facing distance L1 between the wall 11b and the upper base plate 2. Groove 2b
Depth L2 is larger than the opening width W. As a result, the viscous fluid 12 that has flowed out of the gap portion C is prevented from flowing into the groove portion 2b.
Be retained in. As shown in FIG. 1, the second hand wheel 13 and the middle plate 3
The second hand wheel spring 14 is fitted between the second hand wheel 13 and the second hand wheel 13 and elastically contacts the second hand wheel 13 to regulate the movement of the second hand wheel 13. Second hand shaft 13b protruding from the center of the second hand wheel 13
Penetrates through the intermediate plate 3 and, together with a minute hand pipe (not shown) and an hour hand pipe (not shown), projects downward from the base plate 1 to form a pointer shaft. A pointer 15 is attached to the tip of the pointer shaft.

When the rotor 4 is rotated by the step motor, the intermittent rotation motion thereof is transmitted to the third wheel & pinion 6 via the drive wheel 5. When the third wheel & pinion 6 rotates, this rotational movement is transmitted from the disk 8 to the intermediate gear 10 via the coil spring 9. Here, the intermittent rotation motion transmitted to the disk 8 is absorbed by the change in speed by the coil spring 9, converted into a smooth rotation motion, and transmitted to the intermediate gear 10. Intermediate gear 10
Rotates the 4th gear 11 meshing with it. The No. 4 gear 11 is further absorbed by the change in speed by the viscous fluid 12, and combined with the absorption of change in speed by the coil spring 9, the second hand makes smoother continuous rotation.

As another embodiment, a cylindrical wall portion 71b is projected on one side of the disk portion 71a of the No. 4 gear 71, and a pinion 71c is provided outside the wall portion 71b and a wall shape is provided inside. The protrusion 71d may be provided, and the wall-shaped protrusion 71d may be loosely fitted in the recess 62a formed in the upper base plate 62 located on the wall side (see FIG. 3). Reference numeral 72 is a viscous fluid, and other reference numerals are the same as those in the first embodiment.

[0020]

According to the present invention, one of the gear and the ground plate viscously coupled to the gear is provided with a protrusion, and the other is provided with a recess into which the protrusion loosely fits, and between the recess and the protrusion. Since the viscous fluid is provided in the gap and the protrusion is provided on the other side, the groove for accommodating the viscous fluid flowing out from the gap close to and facing the gap is provided at the root of the protrusion. Does not turn into kana. As a result, the viscous coupling gear device can be made compact and thin.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a sectional view of an essential part of another embodiment of the present invention.

[Explanation of symbols]

 2,62 Ground plate (upper ground plate) 2a, 71d Projection part 2b, 71e Groove part 11,71 Gear (4th gear) 11d, 62a Recessed part 12,72 Viscous fluid C Gap part

Claims (1)

[Claims] 1. A protrusion is provided on one of the gear and a ground plate viscously coupled to the gear, and a recess into which the protrusion is loosely fitted is provided on the other side, and the recess and the protrusion are provided. The viscous fluid is provided in the gap between the two, and the other of the protrusions is provided with a groove for accommodating the viscous fluid flowing out from the gap in close proximity to the gap. A viscous coupling gear device, wherein the viscous coupling gear device is provided at a base portion of the protrusion.