JPH0518521Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is suitable for applications where the frequency of gear changes is low, such as the pawl shaft shift of a rotary tiller or the adjustment of plant spacing in a rice transplanter. The present invention relates to a gear transmission device used in a transmission section that maintains

[Conventional technology]

Conventional gear transmissions have generally been configured so that a power transmission path from an input gear to an output gear can be switched by operating a lever.

FIG. 3 shows an example of a pawl shaft transmission device for a rotary tiller, in which torque can be transmitted by spline fitting to the first shaft 11 to which power is input, and the lever 14 can be operated. The shift gear 15 is externally fitted so as to be movable in parallel, and the shift gear 15 is moved toward the first gear 12 that is loosely fitted to the distal end side of the first shaft 11.
2, the power transmission path changes from the first gear 12 to the second gear 18 and third gear 13.
The shift gear 15 is moved to the fourth gear 19 side to reach the fourth gear 19 on the output side loosely fitted to the base end side of the first shaft 11. By engaging with the first gear 12 and the second gear 18, the power transmission path is connected to the first gear 12 and second gear 18.
In addition, there was a configuration in which the gear was directly connected to the fourth gear 19 without passing through the third gear 13, and the chain was transmitted from there to the pawl shaft located below in the figure.

[Problem that the invention attempts to solve]

Such a conventional transmission needs to be equipped with a switching lever and its accessory parts, and also needs to arrange some gears with appropriate distances from each other. That is, to explain using the conventional example described above, it is necessary to equip the switching lever 14 and the shift gear 15 that is moved in parallel by the operation of the lever 14, and the first gear 12 and the fourth gear 19 are need to be spaced apart from each other so that the shift gear 15 can move in parallel therebetween.

The present invention was devised in view of this situation, and aims to provide an inexpensive and compact transmission device that does not require parts such as a switching lever or a shift gear, and can compactly integrate each part. .

[Means for solving problems]

The gear transmission device according to the present invention arranges a first shaft for input and a third gear for output concentrically, and transmits power from the first shaft to the third gear as described in [A] to A gear transmission device configured to be operated by a gear transmission mechanism having the configuration described in [d].

[B] The gear transmission mechanism includes a second shaft arranged parallel to the first shaft, a fourth gear mounted on the second shaft, and a fourth gear mounted on the first shaft and second shaft. It is composed of a first gear and a second gear.

[B] The third gear and the fourth gear are mounted to be rotatable relative to the first shaft and the second shaft, respectively, and are provided with an engaging portion protruding in the axial direction on one side.

[C] The first gear and the second gear each have a first gear.
The shaft is mounted so as to rotate integrally with respect to the shaft and the second shaft, and each is configured to be attachable and detachable to either the first shaft or the second shaft by exchanging the mounting shaft. There is.

[d] The first gear includes an engaging portion on one side thereof that can be selectively engaged with either the engaging portion of the third gear or the engaging portion of the fourth gear, The second gear is arranged so as to maintain a non-engaged state with the engaging portion of the third gear and the engaging portion of the fourth gear when attached to either the first shaft or the second shaft. The functions and effects are as follows.

[Effect]

In a transmission with such a configuration, when the first gear is externally attached to the first shaft, the power transmission path will directly connect from the first gear to the third gear, while the first gear will be externally attached to the second shaft. When fitted, the power transmission path is from the second gear through the first and fourth gears to the third gear.
This brings us to the gear.

[Effect of idea]

Therefore, when using the speed change device of the present invention,
A large gear ratio can be obtained by using four gears, which is the same as that of the conventional speed change device shown in the figure. Moreover, since the speed change is achieved by replacing the first gear and the second gear with the first shaft and the second shaft, rather than by operating a shift lever as in the conventional speed change device, the shift lever, shift gear, and other parts are not required, and the space for the shift gear to move in parallel is also not required, and each part can be compactly arranged. As a result, the speed change device of this invention is inexpensive and compact, and can be effectively used in transmission systems that do not change gears frequently.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a pawl shaft transmission device of a rotary tiller will be described based on the drawings.

In Fig. 1, reference numeral 1 denotes a first shaft that is interlocked and connected to the PTO shaft of the power tiller body via an auxiliary chain case to which power is input. A first gear 2 provided with engaging portions 2a is spline-fitted and externally fitted to enable torque transmission. Further, on the base end side of the first shaft 1, claw-shaped engaging portions 3a that can be engaged with the engaging portions 2a from the axial direction are provided on the side surface facing the first gear 2. A third gear 3 having teeth formed on its peripheral surface on the distal end side is loosely fitted through a bush 4. Note that the third gear 3 is used as an output gear. That is, the sprocket 6, around which the output chain 5 is wound, is spline-fitted to the proximal end of the sprocket 6 so as to be able to transmit torque. Although not shown, the chain 5 is wound around a passive sprocket provided on a lower pawl shaft (not shown).

Furthermore, a second gear 8 that meshes with the first gear 2 is spline-fitted to the distal end side of the second shaft 7, which is arranged parallel to the first shaft 1, and is externally fitted to enable torque transmission. ing. In addition, the second gear 8
The side surface of the first gear 2 is not provided with protrusions such as the engaging portions 2a provided on the side surface of the first gear 2. Further, the outer diameter dimensions and spline shapes of the first gear 2 fitting portion of the first shaft 1 and the second gear 8 fitting portion of the second shaft 2 are configured to correspond, and the first gear 2 and second gear 8 are designed to be interchangeable.

Further, a fourth gear 9 that meshes with the third gear 3 is loosely fitted on the base end side of the second shaft 7 via a bushing 10. The second shaft 7 is provided with claw-shaped engaging portions 9a that engage with the engaging portions 2a of the first gear 2 from the axial direction when the second shaft 7 is externally fitted as shown in FIG.

If the transmission is configured as described above,
When the first gear 2 is externally attached to the first shaft 1 as shown in FIG. 1, the power transmission path goes directly from the first gear 2 to the third gear 3, resulting in a high-speed transmission state.
When the first gear 2 is externally attached to the second shaft 7 as shown in FIG. (deceleration) transmission state.

[Another example]

In the above-mentioned embodiment, the engaging portions provided on each side of the first gear 2, third gear 3, and fourth gear 9 were claw-shaped, but pin holes were formed on each side, The engaging portion may be provided by fitting a pin into the pin hole so that its head protrudes.

Note that although reference numerals have been entered in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of drawings]

1 and 2 show an embodiment of the gear transmission according to the present invention, and FIG. 1 is a longitudinal sectional view showing the main parts;
FIG. 2 is a longitudinal sectional view showing a state in which the first gear and second gear of the transmission shown in FIG. 1 have been replaced. FIG. 3 is a vertical cross-sectional view of a main part of a conventional transmission. 1...First shaft, 2...First gear, 2a...Engaging portion, 3...Third gear, 3a...Engaging portion, 7...Second shaft, 8...Second gear, 9 ...4th gear, 9a...
...Engagement part.

Claims (1)

[Claims for Utility Model Registration] The first shaft 1 for input and the third gear 3 for output are arranged concentrically, and
A gear transmission device configured to transmit power to the gear 3 by a gear transmission mechanism having the configurations described in [A] to [D] below. [B] The gear transmission mechanism includes a second shaft 7 disposed parallel to the first shaft 1, a fourth gear 9 attached to the second shaft 7, and
It is composed of a first gear 2 and a second gear 8 attached to a shaft 7. [B] The third gear 3 and the fourth gear 9 are
Engagement portions 3a and 9a are provided on one side of the shafts, respectively, so as to be rotatable relative to the first shaft 1 and the second shaft 7, respectively, and protrude in the axial direction. [C] The first gear 2 and the second gear 8 are mounted so as to rotate integrally with respect to the first shaft 1 and the second shaft 7, respectively, and each of the first gear 2 and the second gear 8 is
It is configured such that it can be attached to and detached from any of the second shafts 7 by replacing the mounting shaft. [D] The first gear 2 has an engagement on one side that can be selectively engaged with either the engagement portion 3a of the third gear 3 or the engagement portion 9a of the fourth gear 9. The second gear 8 is provided with a joint part 2a, and the second gear 8 has a joint part 2a.
The gear is disposed so as to maintain a non-engaged state with the engaging portion 3a of the third gear 3 and the engaging portion 9a of the fourth gear 9 when attached to either the shaft 1 or the second shaft 7. be.