JPH0137250Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a transmission case in a tiller or the like.

So-called management machines such as small-sized tillers, inter-cultivators, and planting machines are mainly used for inter-tilling between row crops and weeding, and are required to be smaller and more compact as a whole, especially in the cultivation case. .

However, the transmission case installed between the wheels has the function of changing the speed of the power from the engine and transmitting it to the axle or PTO shaft by gear transmission or chain transmission using a combination of many gear groups. In order to fulfill the above-mentioned functions, such as the shift range of the sliding gear that governs the shift range and the space for each gear to be placed, sufficient space is required, and there is a certain limit to how small and compact the gear can be made. In particular, in a structure in which a side clutch is provided on an axle and a link shaft for operating the side clutch is rotatably supported within a transmission case, a boss is provided in a part of the transmission case to support the link shaft. It is necessary to have the boss part protrude inward of the case and to space it a certain distance apart so that the boss part does not interfere with the adjacent gears, which is an inconvenience that forces the capacity of the transmission case to become large. It was hot.

In view of this, the present invention provides a support boss for the link shaft in a connecting stepped portion of a transmission case formed by a wide upper gear storage chamber and a narrow lower chain storage chamber, and also provides support for the link shaft. A notch 12a is provided in a part of the inner wall surface of the inner end side of the link shaft 13 facing the gear in the thick part of the transmission case that forms the boss part, and the link shaft 13 portion in the notch 12a is cut out. The parallel shaft and the link shaft 13 are exposed inside the transmission case 1, and the inner end of the support boss on the opposite side to the notch is substantially aligned with the narrow side wall of the transmission case. By providing such a structure, the link shaft and the gear shaft adjacent to the link shaft can be arranged as close as possible, thereby making the transmission case smaller and more compact. The purpose is to improve lubrication of the link shaft, thereby making clutch operation smooth and stable.

The structure of the present invention will be explained with reference to an embodiment shown in the drawings. Reference numeral 1 is a transmission case for a tiller, etc. The upper part of the case 1 is a wide transmission gear storage chamber M, and the lower part is a transmission case M. It is a narrow transmission chain storage room P. The transmission gear storage chamber M houses various shafts such as an input shaft (transmission shaft) 2, an intermediate shaft 3, an auxiliary transmission shaft 4, an output shaft 5, etc., and each of these shafts is equipped with a gear group that constitutes a transmission mechanism. The power of the engine is transmitted to an output shaft 5 whose speed is appropriately changed by a shift operation not shown, and then transmitted to an axle 6 by chain transmission. 7 is a drive sprocket fixed to the output shaft 5, 8 is a driven sprocket fixed to the axle 6, and 9 is a transmission chain suspended between the sprockets 7 and 8.

Final gears 10 and 11 are spline-engaged with the left and right sides of the output shaft 5, respectively, with the drive sprocket 7 in between. As shown in FIG. 2, oil is contained in the transmission case 1, and the lower portions of the final gears 10 and 11 are immersed in the oil during normal operation.

12, 12 is the link shaft 1 for operating the side clutch
3 and 13, the boss parts 12 and 12
As shown in FIG. 2, the boss portion 12 is provided with a slightly thick wall at the connecting step between the transmission chain storage chamber M and the transmission chain storage chamber D of the transmission case 1, and the inner end of the case 12 is provided with a transmission chain. It has a structure that is substantially aligned with the side wall of the case that constitutes the chain storage chamber D.

and an upper part on the inner end side of the boss parts 12, 12;
That is, the portion facing the final gears 10, 11 is cut out to form a notch 12a, and the outer peripheral surfaces of the link shafts 13, 13 are exposed inside the transmission case 1 at the notches 12a, 12a. ing.

Reference numerals 14 and 14 indicate side clutch operation connection wires, one end of which is fixed to the side clutch (not shown) provided on the axle 6, and the other end connected to arms 15, 15 fixed to the inner ends of the link shafts 13, 13. are connected to each other.

Arms 16, 16 are fixed to the outer ends of the link shafts 13, 13, and wires 17, 17 led out from side clutch levers (not shown) are connected to the arms 16, 16. Reference numeral 18 denotes a protective cover that is integrally provided on the fender 20 that is integrated with the engine frame 19 by a method such as welding or bolting, and the external link parts 21, 21 are shielded from the outside by this protective cover 18. It has a closed structure.

Although the present invention is constructed as described above, in particular, the notch 12a is provided in a part of the inner wall surface on the inner end side of the link shaft 13 supporting boss portion 12 facing the final gears 10, 11. The link shaft 13 and the output shaft 5 can be brought closer to each other by the amount of the notch, thereby making it possible to make the transmission case 1 smaller and more compact. The connecting step portion of the transmission case 1, which is formed by the gear storage chamber M and the narrow lower chain storage chamber D, is formed into a slightly thicker shape, and the support boss portion 12 on the opposite side from the cutout portion 12a is formed.
The inner end of the hub is made to almost match the narrow side wall of the transmission case 1, so even if a large load is applied to the inner end of the boss when the side clutch is operated, this can be strongly held by the side wall of the chain storage chamber D. Even if the upper part of the boss part 12 on the opposite side is notched, there will be no strength problem, and not only will the clutch operation be stabilized, but the link shaft 13 at the notch part 12a can be cut out.
Since a portion thereof is exposed inside the transmission case 1, the lubrication of the rotating portion of the link shaft 13 is improved.

Like the conventional one, the boss part 12 has a notch 12a.
In the case where the boss part 12 is thick, it is not only impossible to reduce the size of the case 1 by reducing the distance between the link shaft 13 and the output shaft 5, but also to reduce the size of the link shaft. The entire outer peripheral surface of the link shaft 13 is surrounded by the boss portion 12, and the link shaft 13
Since the inner end of the link shaft 13 was covered by the arm 15, the lubrication of the link shaft 13 was poor.
Particularly, when the oil level drops below the link shaft 13, the lubrication effect of the link shaft 13 is significantly reduced. However, as in the present invention, the gear storage chamber M and chain storage chamber D of the transmission case 1 By providing the cutout portion 12a in the boss portion 12 at the connecting step portion, these difficulties can be solved at once.

In addition, since the external link part 21 of the present invention has a sealed structure with the protective cover 18, mud, pebbles, etc. scattered by wheels, work equipment, etc. can be removed from the fender 2.
Therefore, it is possible to reliably eliminate the problem of accumulation of mud or the like that would hinder the rotation of the arm 16.

In short, the present invention provides left and right side clutches on the axle 6, and supports the left and right link shafts 13 for operating the side clutches in the transmission case 1 so as to face each other so as to be rotatable. A parallel shaft with a gear is provided at the upper part of the link shaft 13, and the lower part of the gear is immersed in oil at normal times. It is provided in the connecting step part of the transmission case 1 formed by the gear storage chamber M and the narrow lower chain storage chamber D, and is also provided in the thick part of the transmission case 1 that forms the support boss part 12. A notch 12 is formed in a part of the inner wall surface on the inner end side of the link shaft 13 facing the gear.
a, and the link shaft 13 in the notch 12a
A portion of the supporting boss portion 12 is exposed inside the transmission case 1 to bring the parallel shaft and the link shaft 13 closer together, and an inner end portion of the support boss portion 12 on the side opposite to the notch portion 12a is exposed inside the narrow transmission case 1. Since it is provided approximately in line with the side wall, the link shaft 13 and the link shaft 1
3 and the adjacent gear can be arranged as close as possible,
Although this makes it possible to make the mission case 1 smaller and more compact,
Even if a large load is applied when the side clutches are operated, their support is reliable, and the link shaft 13
This has the effect of ensuring good lubrication at all times, making clutch operation smooth and stable.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention,
FIG. 1 is a side view of the mission case, FIG. 2 is a longitudinal sectional front view of the main part, and FIG. 3 is a longitudinal sectional side view of the boss portion. 1...Mission case, 6...Axle, 12...
...Boss part, 13...Link shaft, M...Gear storage chamber, D...Chain storage chamber.

Claims (1)

[Scope of utility model registration request] Left and right side clutches are provided on the axle 6, and the left and right link shafts 13 for operating the side clutches are rotatably supported in the transmission case 1 so as to face each other on the left and right sides, and the upper portions of both link shafts 13 are The supporting boss portion 1 of the link shaft 13 is provided with a parallel shaft equipped with a gear, and the lower part of the gear is immersed in oil during normal operation.
2 is provided at the connection step portion of the transmission case 1 formed by the wide upper gear storage chamber M and the narrow lower chain storage chamber D, and the transmission case that forms the support boss portion 12. A notch 12a is provided in a part of the inner wall surface of the inner end side of the link shaft 13 facing the gear in the one thick part.
The link shaft 13 portion in a is exposed inside the transmission case 1, and the parallel shaft and link shaft 13 are
A transmission in a tiller, etc., characterized in that the inner end of the support boss 12 on the opposite side to the notch 12a is provided so as to substantially match the narrow side wall of the transmission case 1. Case.