JPH0318765Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a chain tensioning structure in which a tightener is provided to be compressed by a transmission chain wound within a transmission case.

[Conventional technology]

In general, in such a chain tensioning structure, one or both ends of a tightener made of a leaf spring or the like is pivotally connected to a boss provided in the transmission case, and the middle of the tightener is pressed into contact with the chain (for example, in practice). 1986-95823).

[Problem that the invention attempts to solve]

In the above conventional structure, in order to provide a boss for attaching the tightener, the shape and processing of the transmission case are not only complicated, but also a support pin is required to connect the tightener to the boss, which increases the number of parts. However, there were disadvantages in terms of implementation and production, and there was room for improvement.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to simplify the transmission case and reduce the number of parts while still allowing the tightener to be attached.

[Means for solving problems]

The characteristic structure of the present invention is that the tightener is made of a spring material and is compressed by a transmission chain wound inside the transmission case, and one end of the tightener is externally fitted onto a shift fork shaft mounted inside the transmission case. The functions and effects are as follows.

[Effect]

That is, while fitting the tightener externally to the shift fork shaft mounted inside the transmission case,
By sandwiching the tightener between the shift fork shaft and the transmission case, one end of the tightener is fixed.

[Effect of idea]

Therefore, the tightener can be attached by externally supporting the shift fork shaft, which is originally provided, so there is no need for a boss to support the tightener, and the shape of the transmission case can be simplified. At the same time, a support pin for fixing the tightener is no longer necessary, and the number of parts can be reduced, resulting in a chain tensioning structure that is advantageous in terms of actual manufacturing.

〔Example〕

FIG. 3 shows an example of a walking rice transplanter equipped with a transmission case 1 having the chain tension structure of the present invention. This walk-behind rice transplanter has an engine 2 and a transmission case 1 that is belt-transmitted to the engine 2 at the front of the machine, and a planting transmission case 3 that also serves as the machine frame towards the rear from the transmission case 1. In addition, the aircraft is equipped with a seedling planting device 4 at the rear of the aircraft, and a control handle 5 extending rearward and upward from the vicinity of the seedling planting device 4.
a pair of left and right propulsion wheels 7 pivotally supported by transmission cases 6, 6 attached to both sides of the transmission case 1;
7, and a group of floats consisting of a front float 8a and a pair of left and right rear floats 8b, which slide on the field, support the field at an appropriate height while sequentially
It is configured to plant seedlings in rows.

In detail, the transmission system inside the transmission case 1 is, as shown in FIGS. 1 and 2, integrally formed with an input shaft 10 on which an input pulley 9 that receives power from the engine 2 is externally fitted. A first gear 11 that meshes with the input gear 10a is loosely fitted into the first transmission shaft 12, and an engagement hole 11a formed in the first gear 11 is fitted loosely into the first transmission shaft 12.
The main clutch sleeve 13, which has an engaging protrusion 13a that engages with the main clutch sleeve 13, is loosely fitted onto the first transmission shaft 12, and then the shift fork shaft 14a is fitted onto the shift fork shaft 14, which is mounted on the transmission case 1. The main clutch mechanism for transmitting power is configured such that the main clutch sleeve 13, which is biased toward the engagement side by the spring 15, is operated toward the disengagement side. A gear 16 is rotatably fitted to the center of the first transmission shaft 12 through a bearing 17, and a manual switching clutch sleeve 18 for adjusting the distance is provided with gears 18a and 18b having different diameters.
are spline fitted. In addition, 19 in the figure is
This is a manual setting lever for adjusting the distance between plants. A second gear 20 that engages with a gear portion 13b formed on the main clutch sleeve 13 is externally fitted onto the second transmission shaft 21, and the power of the input gear 10a is transmitted through the main clutch sleeve 13 and the second gear 20. The power transmitted from the second transmission shaft 21 is transferred to the clutch sleeve 18.
In order to transmit power, gears 12a and 21a are fitted onto the first and second transmission shafts 12 and 21, respectively, so as to mesh with each other. Gears 22 and 23 are arranged in parallel toward the center of the body of the second gear 20,
A traveling clutch sleeve 25 in which these gears 20, 22, 23 are spline-fitted to a third transmission shaft 24.
It is configured so that it can be interlocked with. By sliding the running clutch sleeve 25, gear portions 25a and 25b of different diameters provided on the clutch sleeve 25 are brought into engagement with the gears 20, 22, and 23. That is, the engagement between the gear portion 25a and the gear 20 causes the forward movement 2.
1st forward speed due to the engagement between the gear portion 25b and the gear 22, the gear portion 25b and the gear 2
By engaging with 3, it is possible to change gears to reverse. 26 in the figure is a slide rod for sliding the traveling clutch sleeve 25, and the slide rod 26 is attached to the shift fork 2.
It is operated by 7. Gear portions 28a and 28b having different diameters are provided approximately at the center of the second transmission shaft 21.
The gear 28 equipped with the gear 28 is fitted onto the gear portions 18a, 18b of the manual switching clutch sleeve 18 for adjusting the spacing in a freely rotating state, and the clutch sleeve 18 is then slid. By switching gear parts 18a, 18b, 28a, and 28b to engage each other, it is possible to switch between the plants in three stages. A gear 29 that meshes with the gear 28 is fixed to an intermediate transmission shaft 30, and a transmission chain 34 is wound around a gear 31 that is arranged in parallel to the gear 29 and a gear 33 that is externally fitted on the planting output shaft 32. When the engine 2 is rotated, the output from the engine 2 is transmitted to the first output shaft 12, the transmitted output is shifted in speed by sliding of the clutch sleeve 18, and the shifted output is transferred to the intermediate transmission. axis 30
The seedling planting device 4 is driven by being transmitted to the planting output shaft via.

A tightener 35 for tensioning the transmission chain 34 is installed inside the transmission case 1, and its installation structure will be described.

As shown in FIG. 1, the shift fork shaft 1 has one end of a dogleg-shaped tightener 35 made of a plate spring material mounted in the transmission case 1.
4, and both ends of the tightener 35 are brought into contact with the inner surface of the case.
5 is configured so that it does not rotate around the shift fork shaft 14.

[Another example]

The present invention can be applied not only to rice transplanters but also to various working machines equipped with a transmission chain 34.

[Brief explanation of drawings]

The drawings show an embodiment of the chain tension structure according to the present invention, in which Fig. 1 is a longitudinal side view of the transmission case, Fig. 2 is a longitudinal rear view of the transmission case, and Fig. 3 is an overall side view of the walking rice transplanter. It is a diagram. 1...Mission case, 14...Shift fork shaft, 34...Transmission chain, 35...Tightener.

Claims (1)

[Scope of utility model registration request] A tightener 35 that is pressed by a transmission chain 34 wound inside the mission case 1 is made of a spring material, and one end of the tightener 35 is supported externally on a shift fork shaft 14 that is mounted inside the mission case 1. Chain tension structure.