JPH069878Y2 - Belt tension type traveling transmission for agricultural vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an agricultural work in which each tension pulley for a plurality of transmission belts having different transmission ratios is selectively turned on / off by one lever operation to shift gears. The present invention relates to a belt tension type traveling transmission device.

[Conventional technology]

Conventionally, it has been configured so that a neutral state, that is, a non-transmission state is once brought about by a lever operation during switching from low speed to high speed and from high speed to low speed (see, for example, Japanese Patent Laid-Open No. 52-31277).

[Problems to be solved by the invention]

In the structure in which the non-transmission state is brought about during the shift change as described above, when shifting from the low speed to the high speed, the traveling system is further temporarily lowered from the low speed rotation state due to the load in the non-transmission state during the shift change, After that, a shock occurred because of switching to a high-speed rotation state.
In particular, in agricultural work vehicles such as rice transplanters that perform work in a wetland where the traveling load is large, the above phenomenon is more likely to appear.

The present invention is to reduce the switching shock at the time of a gear shift operation and to suppress a sudden and temporary decrease in power due to the switching by devising the switching means of the transmission.

[Means for solving problems]

The characteristic configuration of the present invention for achieving the above object is to operate the operation lever and each tension pulley by operating the lever.
The point is that both transmission belts are linked by a pulley operated on the disengagement side and a pulley operated on the entry side via a linkage mechanism that exposes a half-clutch state.

[Action]

Both the transmission belts are in the slip transmission state, that is, the half-clutch state by the tension pulley operated on the entry side and the tension pulley operated on the cutting side. The non-transmission state is not brought on the way.

[Effect of device]

Since the gear shift is performed via the half-clutch state, the gear shift from low speed to high speed can be smoothly performed with less shock.

〔Example〕

The drawing shows a riding type rice transplanter, which is an example of an agricultural vehicle, and a seedling planting device (4) is connected to a rear part of a traveling machine body (2) equipped with a driver's seat (1) via a link mechanism (3), The seedling planting device (4) can be moved up and down by a hydraulic cylinder (5) that moves the link mechanism (3) up and down.

The traveling machine body (2), power is transmitted from the engine (E) to the mission (M) via the triple belt transmission (A) also serving as the main clutch, and the wheels (6a), (6b) and seedlings are transmitted from the mission. Power is transmitted to each device such as the planting device (4).

The tribble belt transmission (A) has one operating lever (1
According to 3), it is configured so that it can be switched to a low speed, a medium speed and a high speed alternatively, and the structure will be described below.

Low, medium and high speed transmission belts with different transmission ratios (7a), (7b),
Each tension pulley (8a), (8b), (8c) for (7c) is 1
It is pivotally attached to the horizontal axis (9) of the book, and is biased toward the entrance side by springs (10a), (10b), (10c), and these tension pulleys (8a ), (8b), (8c)
3 on the control side via each link mechanism (11a), (11b), (11c)
The two rocking arms (12a), (12b), (12c) are respectively connected.

Each of the swing arms (12a) is configured to be swingable by respective cams (15a), (15b), (15c) fixed to the rotary shaft (14) of the lever (13). ing.

That is, the rollers (16a) attached to the swinging arms (12a) ... are provided to the arms (15a) ..
Recesses (17a), (17b) and (17c) into which a), (16b) and (16c) fall are formed, and when the rollers (16a) fall into the recesses (17a), the tension pulley ( 8a) ... is operated on the entrance side, and when it comes out of the recesses (17a) ..., it is operated on the cutting side.

The recesses (17a) formed on the cams (15a) ... are arranged such that the recesses (17a) ...
When operating the lever (13) from low speed to medium speed, or from medium speed to high speed, both transmission belts (7a and 7b) or (7b and 7c) are both in slip transmission state, that is, a half clutch. In order to bring about a state, the phase of each recess (17a) ... Is set and provided.

In other words, taking the medium speed transmission belt (8b) as an example,
The clutch engaged state of FIG. 2 to the half clutch state of FIG. 3 and the clutch disengaged state of FIG. 4 are configured to appear.

And, in each of the cams (15a), in the same phase, when all the transmission belts (7a) are cut, a small detent recess (18a) for maintaining the cut state, (18b),
(18c) is formed.

The cams (15a), (15b) and (15c) are lower links (3A).
When the seedling planting device (4) is lifted above a certain level by the arm (3a) attached to the plant, that is, the height position of the seedling planting device is changed due to the change in the depth of the cultivator and the work is lifted above the working lifting range It is configured so that when it is lifted up to, the high-speed transmission state is switched to the low-speed transmission state.

In the above embodiment, the relationship between the swing lever and the operation lever, which are connected to the tension pulley via the link mechanism, has been illustrated, but the roller is attached to the place where the link mechanism of the tension arm equipped with the tension pulley is connected. Then, the roller may be directly operated by a cam.

Further, in the above embodiment, the third speed is exemplified, but the second speed may be used.

Further, in the case of the second speed, in addition to the means by the cam, as shown in FIG. 6, the link (19) is used to set the link ratio, and the pulley operated on the entry side and the cutting side are operated. Depending on the pulleys that are operated, both transmission pulleys may be configured to be shifted after the half-clutch state appears.

The cam group provided with the recess and the links having different lever ratios are referred to as a linkage mechanism (B) in which both transmission belts are in a half-clutch state.

[Brief description of drawings]

The drawings show an embodiment of a belt tension type traveling transmission device for agricultural vehicles according to the present invention. FIG. 1 is a perspective view showing the belt tension type transmission device, and FIGS. 2 to 4 are side views showing the operating state of a cam. Fig. 5 is a side view showing the whole rice transplanter,
FIG. 6 is a schematic view showing another embodiment. (7a), (7b), (7c) …… Transmission belt, (8a), (8b), (8c) …… Tension pulley, (13) …… Lever, (B) …… Coupling mechanism.

Claims (1)

[Scope of utility model registration request] 1. A plurality of transmission belts (7a), (7) having different transmission ratios.
Tension pulleys (8a), (8b), (8c) for b) and (7c)
In a belt tension type traveling speed change device for an agricultural work vehicle which selectively turns on and off by operating one lever (13), the operating lever (13) and each tension pulley (8
Both a), (8b), and (8c) are operated by the lever (13) so that both transmission belts (7a and 7b or 7b and 7c) are operated by the pulley operated on the cutting side and the pulley operated on the entrance side. A belt-tensioned traveling speed change device for agricultural work vehicles, characterized in that they are linked via a linking mechanism (B) that shows a half-clutched state.