JP3104376B2 - Clock wheel train - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a clock train.

[0002]

2. Description of the Related Art In a hand-held timepiece, the rotation of a drive source such as a step motor is transmitted to hands such as an hour hand, a minute hand and a second hand via a wheel train mechanism comprising a plurality of wheel trains, and the hands are operated. Indicates the time. In such a train wheel mechanism, in order to make the hour hand, minute hand, and second hand the same center of rotation, a second pinion pinion that moves the minute hand is rotatably arranged in an hour wheel that moves the hour hand. It has a structure in which the axis of the fourth wheel that moves the second hand is rotatably arranged. In the fourth wheel of this wheel train mechanism, a fitting hole 4 is provided at the center of a gear portion 3 in which a fourth gear 1 and a fourth pinion 2 are integrally formed on the same shaft as shown in FIG. By press-fitting the lower press-fitting portion 6 of the shaft 5 into the fitting hole 4, the gear portion 3 is press-fitted and fixed to the shaft 5, and the flange-shaped pressing portion 7 provided on the shaft 5 is attached to the upper surface of the gear portion 3. The abutment prevents the shaft 5 from tilting with respect to the gear portion 3.

[0003]

However, in such a fourth wheel, since the shaft 5 is inserted into the cylindrical pinion of the second wheel, the diameter of the shaft 5 is formed small. Lower press-fit portion 6 of shaft 5 press fit into fitting hole 4 of gear portion 3
Is formed smaller than the diameter of the shaft 5 because the root circle of the fourth pinion 1 is substantially the same as the diameter of the shaft 5. For this reason, in this fourth wheel, even if the lower press-fitting portion 6 of the shaft 5 is press-fitted into the fitting hole 4 of the gear portion 3, a sufficient holding force cannot be obtained because the diameter of the lower press-fitting portion 6 is small. There is a problem that the holding force is reduced due to a temperature change or a change over time, and the gear portion 3 and the shaft 5 slip with each other. In order to increase the holding force, the gear portion 3 is formed of a high-strength material, and
When the pressure input is increased by slightly reducing the pressure, there is a problem that the gear portion 3 is cracked. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wheel train of a watch capable of increasing the holding force by increasing the diameter of a press-fit portion of a shaft and a gear. .

[0004]

In order to achieve the above object, the present invention provides a metal shaft having a flange-shaped large-diameter press-fit portion formed therein, a through hole into which the shaft is inserted, and the large-diameter press-fit. A synthetic resin gear having a fitting recess into which the portion is press-fitted and formed coaxially, wherein the large-diameter press-fit portion is press-fitted into the fitting recess, and an inner peripheral surface of the fitting recess and the large-diameter When the outer peripheral surface of the press-fit portion is pressed against each other, the shaft and the gear are fixed.
The outer diameter of the large-diameter press-fit portion.
The axial length of the press contact surface that presses against the inner peripheral surface of the joint recess is as described above.
The tooth width of the gear is smaller than the tooth width of the gear;
It is characterized in that it is press-fitted and fixed in the fitting recess within the width .

[0005]

According to the present invention, the large-diameter press-fit portion of the shaft is formed large in the form of a flange, and this large-diameter press-fit portion is press-fitted into the fitting recess of the gear. The mutual pressing force with the inner peripheral surface of the shaft increases, and the holding force between the shaft and the gear increases. Ma
In addition, the pressure contact surface of the large-diameter press-fit portion that presses against the inner peripheral surface of the fitting concave portion
The axial length is made thinner than the gear tooth width, and the diameter is large.
Press the press-contact surface of the press-fit portion into the fitting recess within the gear tooth width.
By pressing in and fixing, the press-in force of the large-diameter press-fitting part is strengthened.
Also, it is possible to prevent cracking around the fitting recess.
Wear.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a fourth wheel. This fourth wheel is axis 10
And a gear unit 20. The shaft 10 is rotatably inserted into a cylindrical pinion of a second wheel (not shown). This shaft 10 has a shaft main body 11 disposed in a cylindrical cannula.
The upper part and the lower part are provided with a vibration-preventing part 12, respectively, a needle mounting part 13 is provided at an upper end part protruding from the cylindrical pinion, the insertion part 14 is provided at a lower end part protruding from the cylindrical pinch, and a flange-shaped large diameter is formed at the upper part. Press-fit portions 15 are provided, each of which is integrally formed of a metal material having high wear resistance such as carbon tool steel. The anti-vibration portion 12 is formed to have a slightly larger diameter than the shaft main body 11, and rotates by contacting the inner peripheral surface of the cylindrical pinion.
This is to prevent the shaft 10 from swinging when rotating. The needle mounting portion 13 is formed in a tapered portion having a smaller diameter than the shaft main body 11, and is press-fitted into the mounting hole 17 of the second hand 16, so that
The second hand 16 is attached. The insertion portion 14 is formed to have a smaller diameter than the shaft main body 11 for the reason described later. Further, the flange-shaped large-diameter press-fit portion 15 has a diameter
Is formed in a disk shape approximately three times as large as the diameter of the disk. A press-contact surface 18 is formed on a lower side of the outer peripheral surface of the large-diameter press-fitting portion 15 in the axial direction (thickness direction), and a tapered surface 1 having an upper portion having a diameter gradually decreasing upward.
9 are formed.

The gear section 20 includes a fourth gear 21 and a fourth pinion 22.
Are provided on the same axis, and these are integrally molded with a polyacetal resin containing potassium titanate. The fourth gear 21 is a spur gear having a thick central portion, and a fourth pinion 22 is integrally formed at the center of the lower surface. This fourth pinion 22 has a tooth root circle formed to have substantially the same diameter as the shaft main body 11 of the shaft 10. The shaft 1 is located at the center of the gear unit 20.
A through-hole 23 through which the zero insertion portion 14 is inserted is provided through the fourth gear 21 and the fourth pinion 22. The through hole 23 has a smaller diameter than the shaft main body 11 because the tooth root circle of the fourth pinion 22 has substantially the same diameter as the shaft main body 11.
For this reason, the insertion portion 14 of the shaft 10 is formed with a smaller diameter than the shaft main body 11. Further, a fitting recess 24 into which the large-diameter press-fit portion 15 of the shaft 10 is press-fitted is provided on the upper surface of the gear portion 20, that is, the upper surface of the fourth gear 21. The fitting recess 24 is a circular recess formed coaxially with the through hole 23.
A ring-shaped rib 25 is provided around the periphery.

In such a fourth wheel, the insertion portion 1 of the shaft 10
4 is inserted into the through hole 23 of the gear portion 20, and the large-diameter press-fit portion 15 of the shaft 10 is press-fitted into the fitting concave portion 24 of the gear portion 20. The outer peripheral surface of the large-diameter press-fit portion 15 is pressed against the inner peripheral surface of the fitting concave portion 24 in a state in which the shaft 10 is in contact with the bottom portion and the inclination of the shaft 10 with respect to the gear portion 20 is prevented. The part 20 will be fixed. In particular, since the large-diameter press-fit portion 15 is formed to be approximately three times as large as the diameter of the shaft main body 11, the mutual pressing force between the outer peripheral surface of the large-diameter press-fit portion 15 and the inner peripheral surface of the fitting concave portion 24 is increased. And the holding force between the shaft 10 and the gear portion 20 increases. For this reason, since the holding force does not decrease due to a temperature change or a change over time, the shaft 10 and the gear unit 20 do not slip with each other, and the gear unit 2 does not slip.
The rotation of 0 can be transmitted to the shaft 10 reliably.
In this case, since the outer peripheral surface of the large-diameter press-fit portion 15 has a tapered surface 19 formed on the upper side thereof, the portion of the tapered surface 19 becomes a flank to the inner peripheral surface of the fitting concave portion 24, and the large-diameter press-fit portion is reasonably large. The press-fit portion 15 can be press-fit into the fitting recess 24.

Next, referring to FIG. 2, a second embodiment of the present invention will be described.
An embodiment will be described. The same parts as those in the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

This fourth wheel and pinion has the same construction as that of the first embodiment except that the shape of the large-diameter press-fit portion 15 of the shaft 10 is different. That is, the outer peripheral surface of the large-diameter press-fitting portion 15 is formed at its lower side with a press-contact surface 30 that presses against the inner peripheral surface of the fitting concave portion 24, and gradually increases in diameter upward above the press-contact surface 30. The tapered surface 31 is formed. In this case, the length of the press contact surface 30 in the axial direction (thickness direction) is shorter than the tooth width t of the gear portion 20, and the press contact portion 30 is
It is press-fitted and fixed to the fitting recess 24 within the zero tooth width t. In other words, the press contact portion 30 has a structure in which the upper end which is the boundary with the tapered surface 31 is press-fitted and fixed in the fitting recess 24 at the same height as the upper end of the tooth width t of the gear portion 20.

In such a fourth wheel, as in the first embodiment, the large-diameter press-fit portion 15 is press-fitted into the fitting recess 24 so that the press-contact surface 30 of the large-diameter press-fit portion 15 becomes the inner surface of the fitting recess 24. , The gear portion 20 is fixed to the shaft 10 with a high holding force. In addition, since the width of the tapered surface 31 of the large-diameter press-fitting portion 15 is wider than that of the first embodiment, the fitting recess 24 is formed.
Press-fitting of the large-diameter press-fitting part 15 to
For this reason, the ribs 25 around the fitting concave portion 24 do not crack or the like, and can be press-fitted very well.

Next, referring to FIG. 3, a third embodiment of the present invention will be described.
An embodiment will be described. Also in this case, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

The fourth wheel is also configured in exactly the same manner as the first embodiment except that the large-diameter press-fit portion 15 of the shaft 10 is different. That is, on the outer peripheral surface of the large-diameter press-fitting portion 15, a large number of concave and convex grooves 35 running in the vertical direction (axial direction) are formed. In such a fourth wheel, when the large-diameter press-fit portion 15 is press-fitted into the fitting concave portion 24, the concave-convex grooves 35 formed on the outer peripheral surface of the large-diameter press-fit portion 15 bite into the inner peripheral surface of the fitting concave portion 24. Therefore, a sufficient torque can be obtained, and the slip between the shaft 10 and the gear portion 20 can be reliably prevented.

Next, referring to FIG. 4, a fourth embodiment of the present invention will be described.
An embodiment will be described. In the fourth embodiment, the large-diameter press-fit portion 1
5, a notch 36 is formed on the inner peripheral surface of the fitting recess 24 of the gear portion 20, and the notch 36 is engaged with the protruding portion 26. And the gear portion 20 are prevented from slipping with each other.

The present invention can be applied not only to the fourth wheel train described in each of the above-described embodiments but also to other wheel trains such as the second wheel train and the third wheel train.

[0017]

As described above, according to the first aspect of the present invention, the flange-shaped large-diameter press-fit portion formed on the shaft is press-fitted into the fitting recess of the gear. Surface and the inner peripheral surface of the fitting concave portion can increase the mutual pressure contact force,
The holding force between the shaft and the gear can be made sufficiently high. For this reason, the holding force does not decrease due to a change in temperature or a change with time, and it is possible to prevent the shaft and the gear from slipping with each other. Also, the axial length of the press-contact surface of the large-diameter press-fit portion that presses against the inner peripheral surface of the fitting concave portion is formed to be smaller than the tooth width of the gear,
In addition, by fixing the press-contact surface of the large-diameter press-fit portion into the fitting concave portion within the tooth width of the gear, even if the press-fit of the large-diameter press-fit portion is increased, cracks are generated around the fitting concave portion. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a fourth wheel of a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a fourth wheel of the second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a fourth wheel of a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a fourth wheel & pinion according to a fourth embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a conventional fourth wheel.

[Explanation of symbols]

 10 Shaft 15 Large-diameter press-fit part 20 Gear part 23 Through-hole 24 Fitting concave part 30 Press-contact surface 35 Uneven groove 36 Notch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-36392 (JP, A) JP-A 54-133875 (JP, U) JP-A 1-168893 (JP, U) JP-A 51- 156867 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G04B 13/02 G04B 19/02-19/04 G04C 3/14 F16B 4/00 F16D 1/06

Claims (3)

(57) [Claims] A synthetic resin in which a metal shaft having a flange-shaped large-diameter press-fit portion formed therein, a through hole into which the shaft is inserted, and a fitting recess into which the large-diameter press-fit portion is press-fitted are formed coaxially. The large-diameter press-fit portion is press-fitted into the fitting concave portion, and the inner peripheral surface of the fitting concave portion and the outer peripheral surface of the large-diameter press-fit portion are pressed against each other, thereby forming the shaft. And the gear are fixed, and of the outer peripheral surface of the large-diameter press-fitting portion,
The axial length of the pressure contact surface pressed against the inner peripheral surface is the tooth of the gear.
And the pressing surface is within the tooth width of the gear.
A timepiece wheel train, wherein the timepiece is press-fitted and fixed in the fitting recess . 2. The wheel train of a watch according to claim 1, wherein an uneven portion that cuts into an inner circumferential surface of the fitting concave portion is formed on an outer peripheral surface of the large-diameter press-fit portion. 3. A notch is formed in the large-diameter press-fit portion,
On the inner peripheral surface of the fitting recess, there is a projection that engages with the notch.
The timepiece according to claim 1, wherein the timepiece is formed.
Wheel train.