JPS598227Y2 - Intermittent rotating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermittent rotation device that can be applied to, for example, a clock mechanism.

As one of the intermittent rotation devices, an intermittent gear mechanism is known, which is used as a carry device in, for example, a totalizing counter or a leaf-type or drum-type digital clock.

However, this known mechanism has complex tooth configurations for both the driving and driven wheels, making it difficult to shape, and the transmission efficiency is significantly inferior to that of regular gears, and the drive source is of high output (for example, an AC motor). It was often used in cases.

An object of the present invention is to obtain a device that can achieve intermittent rotation by meshing teeth in the same plane.

Another object of the present invention is to improve the transmission efficiency in an intermittent rotating device that generally has poor transmission efficiency.

Still another object of the present invention is to manufacture the driving gear and the driven gear inexpensively and easily.

An embodiment of the present invention will be described.

As shown in FIG. 1, a minute drum 1 in a digital display type timepiece is pivotally supported by a central shaft 2, and a frame 3 of the minute drum is supported by a central shaft 2.
A minute gear 4, which is a driving gear, is pivotally attached to the projecting end of the minute drum, and this minute gear rotates in conjunction with the rotation of the minute drum.

A reverse gear 6, which is a driven gear, meshes with the minute gear 4, and the shapes of the teeth 5 and 7 of both gears are as shown in the second figure.

That is, the tooth portion 5 of the minute gear 4 has a trapezoidal shape in which the tip end surface in the rotational direction almost coincides with the line 14 in the radial direction, and the tooth portion 7 of the minute gear 6 has a trapezoidal surface that connects with the minute gear. Radial direction 15
It has a sawtooth shape that almost matches the .

The pitch of the tooth portions of the minute gear 4 is slightly shorter than twice the pitch of the minute wheel 6, and in the illustrated example is about 1.8 times.

There is a protrusion 1 on the surface of the hour hand gear that meshes with the hour hand pinion 8.
0 is provided, and this protrusion can be fitted when facing the hole 12 of the reference wheel 11.

The position at the start of meshing between the minute gear 4 and the minute gear 6 (0 minute or 5 minutes) is such that the pitch of the minute gear 4 on this day is
Since it is 1.8 times that of
3, or a radial line 14.
Each meshing surface 5 of each tooth portion 5, 7 located along 15
a and 7a are in contact with each other.

The operation will be explained.

Continuous rotation of the minute gear 4 in the counterclockwise direction from the position shown in FIG. 2A causes the minute gear 6 to rotate in a clockwise direction.

When one minute has elapsed from the position shown in 2A, the position shown in 2B is reached.

After another 30 seconds have passed, the position shown in 2C is reached.

After another minute has elapsed, the position shown in 2D is reached.

After another 30 seconds have elapsed, the position shown in 2E is reached.

2nd E after 3 minutes have passed since the start of engagement shown in 2nd A
In the illustrated position, the meshing surface 5a of the tooth 5 is line 16
, the meshing surface 7a of the tooth 7 is along the line 17, and at this position the tooth 5 finishes feeding the tooth 7.

That is, while the minute gear 4 rotates through the central angle formed by lines 14 and 16, the minute gear 6 is moved by the central angle formed by lines 15 and 17.

Then, the rotation is not transmitted to the minute gear 6 for 2 minutes while the tooth portion 5 of the minute gear 4 rotates around the center angle from the position along the line 16 shown in the second E diagram to the position along the line 18 shown in the second A diagram. figure,
The meshing surface 7a remains in the position along the line 17, and the outer periphery of the trapezoidal tooth portion of the minute gear 40 slides on the tooth tip of the reverse gear at this time, locking the rotation of the reverse gear. There is.

In this way, of the 5 minutes of continuous rotation of the minute gear 4, the minute gear 6 is sent for the first 3 minutes, but the minute gear 6 is rotated intermittently in the latter 2 minutes without sending the minute gear.

Due to this intermittent rotation of the date gear 6, the hour hand wheel 9 also rotates intermittently.

In other words, the rotation of the minute hand gear 4 for 3 minutes causes the hour hand wheel 9 to rotate.
performs a rotation for 5 minutes, that is, a rotation with a central angle of 2.5°.

Figure 3 shows a graph of the relationship between time and the amount of movement of the hour hand gear.

If the horizontal axis is time t (minutes) and the vertical axis is the center angle θ (degrees) of rotation of the hour hand gear, then the hour hand gear 9 is rotated in a continuous manner, compared to graph 19 when the hour hand gear 9 rotates continuously. In graph 20 where the gear rotates intermittently, the rotational speed of the hour hand gear is faster, and the accuracy of the guideline is therefore higher.

According to conventional continuous rotation, the standard accuracy is about ±5 minutes, so the standard settings are set at 10-minute intervals, but with the intermittent rotation of the present invention, the accuracy of the teeth on the same plane is Although it is engaged and has a simple tooth profile configuration, the standard accuracy is about ±1 minute, and the standard setting can be set at 5 minute intervals.

As described above, according to the present invention, intermittent feeding and locking of the driven gear can be realized by meshing the tooth portions on the same plane.

Furthermore, according to the structure of the present invention, it is possible to set the start of meshing to be as late as possible in one cycle of feed of one tooth of the driven gear by the driving gear, and the starting point of meshing can be set to the line connecting the centers of both gears. Since the pressure angle at that time is close to , and the pressure angle at that time is small, the transmission efficiency is better than the known partially toothed gear mechanism or Geneva mechanism.

Furthermore, since the tooth profile structure is simple, it is easy to manufacture a mold for the preform, and both the driving gear and the driven gear can be produced at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which the first figure is a sectional view and the second figure is a cross-sectional view.
AE is a partial front view for explaining the driving state from the driving gear to the driven gear, and FIG. 3 is a graph showing the relationship between the amount of movement of the hour hand gear and time. 4... Drive gear (minute gear), 5... Teeth of drive gear, 6... Driven gear (minute gear)
, 7... Teeth of driven gear, 5a, 7a...
...Meshing surface of teeth, 13... Line connecting the centers of the driving gear and driven gear.

Claims (1)

[Claims for Utility Model Registration] Consisting of a driving gear and a driven gear that meshes with the driving gear and rotates intermittently, the teeth of the driving gear have a base whose end surface in the rotational direction is approximately aligned with the radial direction. The teeth of the driven gear have a sawtooth shape in which the surface that engages with the tip end surface of the trapezoidal tooth of the drive gear is substantially aligned in the radial direction, and the trapezoidal tooth of the drive gear has the following shapes: The pitch is approximately twice the pitch of the teeth of the driven gear, and after the tooth of the driven gear has been fed one tooth, the tip of the teeth of the driven gear until just before starting to feed the next tooth. An intermittent rotation device characterized in that the tooth tip has a tooth width that allows sliding contact.