JPH0617887A - Power transmission gear - Google Patents

Abstract

PURPOSE:To provide a normally/reversely rotatable power transmission gear for a facsimile device or the like easy to manufacture and capable of distributing power by providing a first gear having retrorse ratchets on both faces, and disposing gears, provided with ratchets to be engaged with the ratchets of the first gear, on both sides of the first gear. CONSTITUTION:Both faces of a gear 23, to which the normal/reverse rotating power of a motor M is transmitted through gears 21, 22, are provided with ratchets 23a, 23b disposed retrorsely and circularly around a rotary shaft. Gears 24, 25 are then disposed on both sides of the gear 23, and ratchets 24a, 25a to be engaged with the ratchets 23a, 23b of the gear 23 are respectively formed at the gears 24, 25. The ratchets 24a, 25a of both gears 24, 25 are of the same shape. Spaces between the gear 23 and gears 24, 25 are formed in such a way that either the ratchets 23a, 25a or 23b, 24a are engaged with each other, and the gears 24, 25 are respectively engaged with gears 26, 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device,
In particular, it relates to a power transmission device that distributes forward and reverse power.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional power transmission device that distributes forward and reverse power in a facsimile machine, for example. The motor M uses the forward rotation power and the reverse rotation power of the gear 1
, Gear 1 to gear 2, and gear 2 to gear 3. The gear 3 has one-way clutches 6, 7 on both sides of its axis of rotation on its axis of rotation, these one-way clutches 6, 7 being incorporated in the respective gears 4, 5.
The forward rotation power is transmitted to the gear 5 via the one-way clutch 7, for example, while the reverse rotation power is transmitted to the gear 4 via the one-way clutch 6. In this way, the conventional power transmission device transmits normal rotation and reverse rotation to each gear via each one-way clutch.

FIG. 5 shows a conventional dog clutch for transmitting and separating power in a transmission of an automobile, for example. The gear 11 and the gear 12 are the gear 11
The dog (claw) 14 of the gear 12 is fitted into the hole 13 of the gear 12 to be connected, and the rotation of the gear 12 is transmitted to the gear 11. The gear 11 and the gear 12 are connected to each other by a suitable means from the outside, for example, by traversing the gear 12 in the direction of the rotation axis. In this configuration itself, the dog 14 of the gear 12 is dragged to the hole 13 of the gear 11. No attempting force, i.e., trying to connect the gears 11 and 12 to each other, is generated.

[0004]

However, in the former conventional technique, since the one-way clutch is used, the structure is complicated and the cost is increased. In the latter conventional technique, a means for traversing the gear is required, and the structure is also complicated and the cost is high.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a power transmission device which is easy to manufacture and has a simple structure for distributing forward and reverse power.

[0006]

In order to achieve the above-mentioned object, the present invention has a first gear having ratchets provided in opposite directions on both sides, and a ratchet capable of engaging with each of the ratchets. And a power transmission device comprising a second gear and a third gear arranged on both sides of the gear. And, preferably, when the first gear rotates in a certain direction, the first gear separates from the second gear and engages with a third gear, and when the first gear rotates in the opposite direction, the first gear becomes The first gear and the second and third gears are arranged to be relatively movable so as to be separated from the third gear and engage with the second gear.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described with reference to the drawings. 1 is a side view of a power transmission device of the present invention, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a main view for explaining the operation of the power transmission device. FIG.

In FIGS. 1 and 2, the forward and reverse power from the motor M is transmitted from the gear 21 to the gear 22, and from the gear 22 to the gear 23. Gear 2
Numeral 3 is arranged so as to slide along its rotation axis 28 as indicated by arrow Y, that is, movably up and down as seen in the drawing, and the rotation axis is centered on both sides of the gear. Is provided with ratchets 23a and 23b arranged in a circular shape. The directions of the claws of the ratchets 23a and 23b are opposite to each other. Gear 2 on the rotating shaft
3, a gear 25 and a gear 24 are arranged above and below the gear 3, and the gears 25 and 24 are engaged with the ratchets 23a and 23b of the gear 23, respectively.
a and 24a. The configuration including the gear 24 and the ratchet 24a is exactly the same as the configuration including the gear 25 and the ratchet 25a, and the same components may be arranged so that the ratchet is inside. The relationship between the intervals of the gears 23, 25, 24 is such that at least one of the ratchets 25a, 24a of the gears 25, 24 engages with at least one of the ratchets 23a, 23b of the gear 23. FIG. 1 shows a ratchet 23 a of the gear 23 and a ratchet 25 of the gear 25.
It shows a state in which a is engaged.

The gear 25 is engaged with the gear 27, and the gear 24 is engaged with the gear 26. Therefore, the power transmitted to the gear 25 is further transmitted to the gear 27, and the power transmitted to the gear 24 is transmitted to the gear 26.

Next, the operation of the ratchet provided on the gear will be described with reference to FIG. The side surface of each pawl of each ratchet of each gear has a substantially trapezoidal shape, and connects these surfaces with an acute angled surface (eg 30, 31), an obtuse angled surface (eg 32, 33) and these surfaces. It consists of a surface parallel to the gear surface. Now ratchet 23a of gear 23 and gear 2
5 is engaged with the ratchet 25a, the gear 23
When is rotated in the direction of arrow X, the claw surface 30 of the ratchet 25a of the gear 25 and the claw surface 31 of the ratchet 23a of the gear 23 are engaged, and a thrust force, that is, a force for pushing the gear 23 downward is generated. To do. Therefore, the gear 23 is pushed downward, and the ratchet 23b of the gear 23 comes into engagement with the ratchet of the gear 24. After the engagement, the pawl surface 35 of the ratchet 23b of the gear 23 and the ratchet 24a of the gear 24 are engaged.
The ratchet 23b of the gear 23 and the ratchet 24a of the gear 24 are completely engaged by the thrust force acting on the surface 34 of the claw of the gear, that is, the force pulling the gear 23 downward, and as a result, the gear 23 is separated from the gear 25. , The state in which the gear 24 is engaged, that is, the state opposite to the state shown in FIG. on the other hand,
When the gear 23 is rotated in the direction opposite to the arrow X, the gear 23 separates from the gear 24 and engages with the gear 25 for the same reason as described above. As described above, the ratchet gear of the present invention can generate a push force-pull force (pressing force-pulling force) to distribute or switch power transmission.

The formation of the ratchet on the gear can be easily performed by upper and lower molds (not shown) having a shape complementary to the surface of the ratchet.

[0012]

As described above, according to the present invention,
The power transmission device has a small number of parts, the manufacturing cost is low,
It has a simple structure and can be made compact.

[Brief description of drawings]

FIG. 1 is a side view of a power transmission device of the present invention.

2 is a cross-sectional view taken along line 2-2 of FIG.

FIG. 3 is an enlarged side view of an essential part for explaining the operation of the power transmission device.

FIG. 4 is a side view showing an example of a conventional power transmission device.

FIG. 5 is a side view showing another example of the conventional power transmission device.

[Explanation of symbols]

 23, 24, 25 gears 23a, 23b, 24a, 25a ratchet

Claims (2)

[Claims] 1. A first gear having ratchets provided in opposite directions on both sides, and second and third gears having ratchets capable of engaging with the respective ratchets and arranged on both sides of the gears. A power transmission device comprising: 2. The power transmission device according to claim 1,
When the first gear rotates in a certain direction, the first gear moves to the second
When separated from the gear and engaged with the third gear and the first gear rotates in the opposite direction, the first gear separates from the third gear and the second gear
A power transmission device characterized in that a first gear and second and third gears are arranged so as to be relatively movable so as to engage with the gear.