JPH0642121Y2 - Small tiller gearbox - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a transmission for a cultivator.

(B) Conventional technology Conventionally, in a small tiller-type cultivator, the auxiliary transmission mechanism of the transmission (mechanism that can be operated during traveling) is
In many cases, the so-called double tension clutch mechanism was adopted. In other words, the output shaft of the prime mover and the input shaft of the transmission were connected by two sets of pulleys and a belt mechanism, and two tensions of the belt were selectively acted to obtain two shifts. This is because, when this method is adopted, the transmission can be downsized, and the structure is simple and the cost is low.

(C) Problems to be solved by the device However, in this method, when the speed is changed to change the speed of the machine, the rotational speed of the PTO shaft provided in the transmission also changes, and the system is driven by this. External output device (eg,
There was the inconvenience that the rotation speed of the cultivator etc. also changed.
For example, if the speed is changed to high speed while cultivating at a low speed, the rotation speed of the cultivating shaft will increase at the same time, which is dangerous, and the prime mover will run out of horsepower and stall. There was also something.

The present invention solves such a problem by providing a no-clutch transmission mechanism in the transmission and replacing it with a double-tension clutch mechanism. It can be taken out as a PTO axis.

(D) Means for Solving the Problems Therefore, the present invention introduces the rotational force of the prime mover to the input shaft of the transmission, and appropriately changes the rotational force of the input shaft to transmit it to the output shaft and the PTO shaft. In a transmission of a machine, a rotational force having a constant rotational speed is introduced to the input shaft, the rotational force is provided between the input shaft and the second shaft, and the gear group is constantly meshed with the gear group. The transmission force is transmitted to the output shaft through a clutchless speed change mechanism that is composed of a clutch body that selects a specific rotational speed, and further, the rotational force of one of the constantly meshed gear groups is connected to the PTO shaft. The above-mentioned problems have been solved.

(E) Action As a result, the speed shift can be easily performed by the sub-clutch shift mechanism described above, and the gear that rotates at the constant rotation speed that constitutes the no-clutch shift mechanism is set on the PTO shaft. The rotation speed becomes constant, which is preferable for the output device.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a developed sectional view of a main part of a transmission showing a specific example of the present invention, and FIG. 2 is a sectional view around the third shaft.

This transmission includes a case 1, an input shaft 2, a second shaft 3, and a third shaft 4.
And the output shaft 5, respectively. Then, in this case, the rotational force of the prime mover is input to a pulley (hereinafter not shown) fixedly fitted to the input shaft 2 at a constant rotational speed, so that this is appropriately decelerated and transmitted to the output shaft 5 or the like. .

Therefore, two types of gears 6 and 7 are fixedly fitted to the input shaft 2, and two types of gears 8 and 9 which are constantly meshed with the gears 6 and 7 are loosely fitted to the second shaft 3. Between the gears 8 and 9, slide between these 8 and 9,
A clutch body 10 is provided which presses the ball 10a contained therein against the groove 3a of the second shaft 3 to enable co-rotation. In addition,
The sliding of the clutch body 10 is performed by the operation fork 11. Thus, if the operating fork 11 is operated and the clutch body 10 is slid, one of the gears 8 and 9 and the input shaft 2 are integrated, and two types of rotation speeds are given to the input shaft 2 and Since this gear shifting operation can be performed without stopping the rotation of the input shaft 2, it constitutes a so-called auxiliary gear shifting mechanism of the clutchless gear shifting mechanism 12. Further, a slide gear 13 that is slidably fixed to the second shaft 3 and a loose fit gear 14 that is fixedly loosely fitted are meshed with each other when the slide gear 13 slides toward the loose fit gear 14 side. It is fitted so that it can be engaged. Further, a transmission gear 15 in which a gear portion 15a which is engaged and disengaged by sliding of the slide gear 13 and a gear portion 15b which is constantly meshed with the loose fitting gear 14 are integrally fitted to the input shaft 2 is loosely fitted. As described above, the gear slide type transmission mechanism 17 in which two kinds of rotation speeds are given to the transmission gear 15 by the slide operation of the slide gear 13 (also performed by the operation fork 16) is configured. On the other hand, the third shaft 4 is the input shaft 2
Adjacent to this, and the gear portion 15a of the transmission gear 15 described above.
And a slide gear 18 that slidably engages with another separately formed gear portion 15c is slidably fitted. Therefore, since the third shaft 4 also obtains two kinds of rotation speeds by the sliding operation of the slide gear 18 (also performed by the operation fork 19), it is convenient to combine it with the rotation speed of the transmission gear 15 described above. It is possible to obtain various kinds of gear shifts (this is the main gear shift mechanism, but these cannot be shifted unless the rotation of each axis is stopped). In addition, by sliding the slide gear 18 beyond the normal sliding range and engaging with the above-mentioned free fitting gear 14 (at this time, the slide gear 13 and the free fitting gear 14 are engaged). The shaft 4 rotates in the opposite direction to the second shaft 3, and the reverse rotation can be obtained. Further, the gears 20 and 21 are fixedly fitted to the third shaft 4 and the output shaft 5, and the two 20, 21 are always meshed, so that the power transmitted to the third shaft 4 passes through the output shaft 5. Is transmitted to an axle (not shown).

By the way, in this case, one of the two types of the loosely fitted gears 8 and 9 loosely fitted to the second shaft 3, that is, the gear 8 on the low speed side close to the wall surface of the case 1 has the largest reduction ratio. The boss 8a is extended to the outside of the case 1 and is formed on the PTO shaft 22. That is, the inner peripheral side is loosely fitted to the second shaft 3, and the outer peripheral side is supported by the bearing 23 or the like with respect to the case 1. A spline or the like is formed on the PTO shaft 22, and a sprocket 24 is fixedly mounted on the spline so that the power transmitted to the spline can be transmitted to an external working device, for example, a tiller. Of.

(G) Effects of the Invention Since the invention has been described above, the following effects can be expected.

That is, the auxiliary transmission mechanism is the above-mentioned clutchless transmission mechanism.
Because it is based on 12, like the conventional double tension system, it is possible to shift gears even while running. In addition, since the PTO shaft 22 is the rotational force of one of the gear groups 6, 7, 8, and 9 that are constantly meshed, it is rotating at a constant rotation speed regardless of gear shifting, and Even if the speed changes, the rotation speed of the external work equipment such as the tiller does not change, and fine work can be performed. Since the take-out structure of the PTO shaft 22 is also used as the clutchless speed change mechanism 22, the clutchless speed change mechanism 12 and the gear slide type speed change mechanism 17 are assembled on the second shaft 3 to be compact. Together, the overall space could be made extremely small, and an optimal transmission could be developed for this type of small cultivator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a developed cross-sectional view of a main part of a transmission showing a specific example of the present invention, and FIG. 2 is a cross-sectional view around a third shaft. (Code) 1 …… Case 2 …… Input shaft 3 …… Second shaft 5 …… Output shaft 6 ～ 9 …… Gear group 10 …… Clutch body 12 …… No clutch transmission mechanism 22 …… PTO shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Moriyasu 428 Enami, Okayama City, Okayama Prefecture Seirei Industry Co., Ltd. In-company (72) Inventor Susumu Noguchi 1-32, Chaya-cho, Kita-ku, Osaka City, Osaka Prefecture Yanma Agricultural Machinery Co., Ltd. (56) Reference JP-A-54-31860 (JP, A) JP-A-50-76465 ( JP, A) JP 57-90455 (JP, A)

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. A rotating shaft of a prime mover, and an input shaft (2) of a transmission.
In the transmission of a small cultivator that guides to the output shaft (5) and the PTO shaft (22) by appropriately changing the rotational force of the input shaft (2), the input shaft (2) is rotated at a constant rotation speed. In addition to guiding the rotational force, the rotational force is applied to a gear group (6), (7), (8), (9) that is always meshed between the input shaft (2) and the second shaft (3). , The output shaft via a clutchless transmission (12) consisting of a clutch body (10) for selecting an alternative rotation speed of the gear groups (6), (7), (8), (9). It is transmitted to (5), and
The gear group (6), (7), (8), (9) that is always meshed
A transmission for a small field cultivator, characterized in that the rotational force of one of the two is connected to the PTO shaft (22). 2. Of the gear groups (6), (7), (8) and (9) according to claim 1, the gear group (6) meshing on the wall side of the case (1). , (8) has the largest reduction ratio, and the gear (8) fitted to the second shaft (3) is set to the PTO shaft (22). Gearbox.