JPH0243782Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an improvement of a transmission mechanism mounted on a tractor.

<Prior Art> In general, agricultural tractors are used as traction vehicles for various types of work equipment, and have a much larger low-speed reduction ratio than cars that drive on paved roads, and require a large number of gears. The series becomes extremely complex, which is not only cumbersome in terms of design and construction, but also the shape of the shaft arrangement is unique in that it tends to be difficult to fit in a narrow space, and this becomes especially noticeable as the tractor becomes smaller. Become.

In this regard, in the conventional transmission mechanism, as illustrated in FIGS. 5 and 6, the clutch 1 is centered on the input main shaft 3 to which the rotational power of the engine 2 is intermittently transmitted, and the transmission mechanism is located above the input main shaft 3. A countershaft 4 for PTO transmission and a countershaft 5 for PTO transmission are mounted horizontally and parallel to each other, and are connected to each other by gears that mesh and rotate with each other.

<Problems to be solved by the invention> As a result, the transmission case 6, which houses a total of three shafts, becomes extremely tall and long, and the driver has to stand on the step protruding from the side of the case 6. While putting his feet on the tractor, he has no choice but to operate it while straddling the case, making it impossible to get on and off the tractor safely and easily.

In addition, it is far from a planar shape with a wide leg area and little undulations like the driver's seat of the above-mentioned car, which makes it less comfortable to live in, and also makes it difficult to install the cabin and other accessories, such as the layout. There are problems that are easily subject to restrictions.

<Means for Solving the Problems> The present invention is intended to solve these problems, and its technical configuration includes an input main shaft in which rotational power of the engine is intermittently received via a clutch. and two countershafts for traveling transmission and PTO transmission which are transmitted from the main shaft. In a tractor transmission mechanism that is located below the rotational axis of the crankshaft and is arranged with equal left and right distribution at the remaining two vertices of an imaginary isosceles triangle, the above-mentioned input is The rear part of the main shaft is bearing on the intermediate partition wall of the clutch housing, and the gear for distributing transmission to both countershafts is integrally fixed to the rear end of the main shaft facing into the gear chamber divided by the partition wall. Both countershafts have the same front hollow shaft that is mounted inside the gear chamber of the clutch housing, and a rear solid shaft that is mounted inside the transmission case that is assembled into the clutch housing from the rear. The same gears spline-fitted onto the front hollow shaft are kept in a transmission state in which they are constantly meshed with the distribution transmission gear of the main shaft, while the rear solid shaft is formed into a front hollow shaft. It is characterized in that both countershafts are directly connected to each other as a whole by spline fitting them into the shaft from the rear.

<Example> Hereinafter, the configuration of the present invention will be specifically explained based on the illustrated example. In FIGS. 1 to 4, 10 is an engine mounted on the front part of the tractor body T;
Reference numeral 11 designates the crankshaft, and a flywheel 12 that rotates integrally with the crankshaft faces into the clutch housing S1, and a spline hub 13 is fixed to the center of the flywheel 12 with bolts 14.

The rear part of the clutch housing S1 is divided into a gear chamber 15 that also serves as a heat dissipation oil tank, and furthermore, a transmission case S2 and a final transmission case S3 are located at the rear part of the clutch housing S1.
are sequentially connected and integrated. Both cases S
2. Of course, S3 also serves as a heat radiation oil tank. The upper surface of the transmission case S2 forms a flat floor 16 as a whole, so that the driver can sit on the driver's seat 17 installed on the final transmission case S3 while using the steering wheel 18 and the like. pedal 1
9 etc. can now be operated without danger to the suspension.

Reference numeral 20 denotes a pair of left and right steps for getting on and off, and the height H between the upper surface and the above-mentioned floor 16 is
Based on the fact that the transmission case S2 is formed one step lower than the clutch housing S1 and the final transmission case S3, it is preferable that the transmission case S2 is flush with the same height or has a small dimension close to this. It is being

Moreover, the step 20 is fixedly suspended not only across the side of the transmission case S2, but also across both sides of the clutch housing S1 and the final transmission case S3, which are parallel to each other in the front and rear positions. Therefore, it also has the function of reinforcing the connection of the three case bodies. 21 is the reinforcing material 2 for attaching the step 20.
2 is also a bolt.

As mentioned above, transmission case S2
The reason why the floor 16 and step 20 can be installed rationally with little difference in height is that the following three shafts are enclosed in a special arrangement within the transmission case S2 and clutch housing S1. It comes from what happened.

That is, in the expanded enlarged plan view of FIG. 4 that clarifies this, 23 is the crankshaft 11.
It is a horizontal input main shaft arranged on the same rotational axis as the main shaft, and the front part thereof is connected to the spline hub 13.
Similarly, the rear part is an intermediate partition wall 24 with the gear chamber 15.
Both are supported via bearings 25 and 26. 27 is a general term for single clutch,
The clutch cover 28 is fixed to the flywheel 12. Reference numeral 29 is also a clutch disk, which is spline-fitted to the main shaft 23. 30 is a pressure plate, 31
is a clutch release hub whose thrust bearing 32 presses a release lever 33.
34 indicates a release fork that hangs down from the clutch lever 35.

The main shaft 23 has a hollow shaft 23 as a whole.
A, and a distribution transmission gear 36 is integrally carved in the rear end facing into the gear chamber 15. Further, 37 and 38 collectively refer to the countershafts for traveling transmission and PTO transmission, and these are mounted horizontally parallel to the main shaft 23, and in particular, both of them are connected to the rotation of the crankshaft 11. They are arranged in a left-right and left-right distribution configuration so as to be located below the axis.

In other words, as is clear from FIG. 2, both countershafts 37 and 38 are aligned with the main shaft 23 so that the main shaft 23 is located at the remaining two vertices Y and Z of the virtual isosceles triangle, which is the top vertex X. In the lower row, they are equally distributed and arranged in parallel so as to form left and right pairs. Therefore, the above three shafts 23, 37, 38
In installing these, the limited internal space of the clutch housing S1 and transmission case S2 can be used rationally, and they can be arranged in a row with an optimal overall weight balance, resulting in a compact tractor. It is particularly effective for The main shaft 23 has a solid shaft, and both countershafts 37 and 38 are attached to it.
The distribution transmission gear 36 may be fixed so as to be integrally rotatable.

Furthermore, 37a is a front hollow shaft 37a forming the front part of the countershaft 37 for traveling speed change, and is installed in the gear chamber 15 of the clutch housing S1, and is connected to the front hollow shaft 37a through a gear 39 spline-fitted thereto. , meshes with the gear 36 of the main shaft 23. Reference numeral 40 denotes a collar for positioning the mesh, which is fitted onto the front hollow shaft 37a. Also countershaft 37
The rear part extends into the transmission case S2 as a rear solid shaft 37b, and the front part thereof is spline-fitted to rotate integrally with the front hollow shaft 37a. In other words, transmission case S to clutch housing S1.
When assembling 2, the countershaft 3
The rear solid shaft 37b of No. 7 is the front hollow shaft 37a.
It is spline-fitted by inserting it from the rear.

The rear solid shaft 37b is connected to the main transmission chamber 4.
1, a plurality of gears 42, 43, 44, 45 forming a traveling gear group are fitted so as to rotate together, and the rear solid shaft 3
A pair of front and rear hub gears 47 and 48 for switching between forward and reverse gears are fitted on the way where 7b faces the sub-transmission chamber 46 so as to freely rotate. 49 is a coupling sleeve for switching between forward and backward movement.

On the other hand, the front part of the PTO transmission countershaft 38 also serves as a front hollow shaft 38a, and the front hollow shaft 3 of the traveling transmission countershaft 37 is also used as a front hollow shaft 38a.
7a, and this front hollow shaft 38a is also mounted within the gear chamber 15 of the clutch housing S1. The gear 36 on the main shaft 23 is connected to the gear 50 spline-fitted onto the front hollow shaft 38a.
It meshes with. That is, the gear 36 installed at the rear end of the main shaft 23 is connected to both front hollow shafts 37a, 38a, which form a pair on the left and right, for common transmission to both countershafts 37, 38.
The rotational power of the main shaft 23 is distributed and transmitted to the two. 51 is a collar for positioning the gear 50. Similarly, the rear part of the countershaft 38 passes through the transmission case S2 as a rear solid shaft 38b forming a PTO shaft to the work machine (not shown), but the hollow countershaft 38
It is supported in a freely rotatable and enclosed state by c. When assembling the transmission case S2 to the clutch housing S1, the sawyer hollow shaft 38b of the PTO transmission countershaft 38 is also spline-fitted to the front hollow shaft 38a by being inserted from the rear. Similarly to the traveling speed change countershaft 37,
The PTO transmission countershaft 38 is directly connected as a whole.

A plurality of gears 52, 53, 54, and 55 are spline-fitted to the hollow countershaft 38c, and constitute a gear group for PTO shifting, which includes a pair of front and rear coupling sleeves 56, 57.
is mediated. Both coupling sleeves 56,5
7 rotates integrally with its own fitted shaft, similar to the coupling sleeve 49 described above;
Needless to say, it is slidably spline-fitted in the axial direction.

Further, both forward and reverse gears 58 and 59 are fixedly installed at the location where the hollow countershaft 38c faces into the sub-transmission chamber 46, and the hub gear 4 on the traveling transmission countershaft 37 is fixedly installed.
It corresponds to 7,48. Reference numeral 60 denotes a reverse idle gear shaft installed in parallel within the auxiliary transmission chamber 46 at a lower position facing the middle of the traveling transmission countershaft 37 and the PTO transmission countershaft 38, and is clearly visible in FIG. The hub gear 48 on the traveling speed change countershaft 37 is connected to the hub gear 48 on the traveling speed change countershaft 37 through the gear 61 loosely fitted therein.
Gear 5 on countershaft 38 for PTO transmission
9 are interlockingly connected.

As I said earlier, both countershafts 3
The front hollow shafts 37a and 38a of 7 and 38 are formed identically, but in order to mesh with the distribution transmission gear 36 on the main shaft 23,
Gears 39 and 50 spline-fitted to both front hollow shafts 37a and 38a are also formed identically. Therefore, the front hollow shaft 37a,
38a and gears 39 and 50 can be used interchangeably for traveling transmission and PTO transmission, and in this sense, the mass production effect can be significantly improved.

<Effects of the Invention> As described above, in the present invention, the rotational power of the engine 10 is intermittently received through the input main shaft 23 via the clutch 27, and the input main shaft 23 is transmitted from the main shaft 23 to the driving gear and PTO.
The main shaft 23 is located at the topmost vertex X defining a virtual isosceles triangle, and both countershafts 37 and 38 are connected to the rotation axis of the crankshaft 11. In particular, in a tractor transmission mechanism in which the shafts are mounted in parallel with each other, with the left and right equally distributed arrangement located at the remaining two vertices Y and Z of the virtual isosceles triangle, the above-mentioned input is below. The rear part of the main shaft 23 is supported by the intermediate partition wall 24 of the clutch housing S1, and the rear end of the main shaft 23 facing into the gear chamber 15 divided by the partition wall 24 is provided with a bearing for both countershafts 37 and 38. The distribution transmission gear 36 is integrally fixed, and both of the countershafts 37 and 38 are mounted on mutually identical front hollow shafts 37a and 38a that are mounted in the gear chamber 15 of the clutch housing S1.
and rear solid shafts 37b and 38b mounted in the transmission case S2 which is assembled from the rear into the clutch housing S1, and mutual spline-fitted shafts on the front hollow shafts 37a and 38a, respectively. identical gears 39, 50
is maintained in a transmission state in which it constantly meshes with the distribution transmission gear 36 of the main shaft 23, while the rear solid shafts 37b, 38b are spline-fitted to the front hollow shafts 37a, 38a, both inserted from the rear. By doing so, the overall countershafts 37 and 38 are directly connected to each other, which has the effect of easily solving the problems of the prior art described at the beginning.

That is, the input main shaft 23 is located at the topmost apex X that defines a virtual isosceles triangle, and both the countershafts 37 and 38 for travel gear shifting and PTO gear shifting are located below the rotational axis of the crankshaft 11. , and the rear part of the main shaft 23 is mounted on the intermediate partition wall 24 of the clutch housing S1, with the left and right equally distributed arrangement located at the remaining two vertices Y and Z of the virtual isosceles triangle. The countershafts 37 and 38 are arranged in an array across the gear chamber 15 and the transmission case S2 behind the partition wall 24. The entire gear room 15 and transmission case S2 located at the rear can be designed to be extremely low-volume, and the floor 16, which is the upper surface of the gear room, can be designed to be as flat as possible with little difference in height between the step 20 and the transmission case S2. As a result, getting in and out of the driver's seat 17 can be done easily.
Also, the livability of the suspension can be improved.

Moreover, in the case of the present invention, both the countershafts 37 and 38 for travel transmission and PTO transmission, which are arranged in an equally distributed left and right state, are connected to the front hollow shafts 37a, 38a and the rear solid shaft 3.
7b, 38b, and in particular the front hollow shafts 37a, 38a.
are mounted in the gear chamber 15 of the clutch housing S1 adjacent to the transmission case S2, while the rear solid shafts 37b and 38b are arranged and mounted on the transmission case S2. When assembling the clutch housing S2 to the clutch housing S1, the rear solid shafts 37b, 3 of both countershafts 37, 38
8b to the front hollow shafts 37a, 38a from the rear and can be easily and correctly spline-fitted, and the assembly workability is excellent. This ensures a stable transmission state.

And the gear chamber 15 of the clutch housing S1
Inside, gears 39 on front hollow shafts 37a, 38a in both countershafts 37, 38,
50 is maintained in a transmission assembled state in which it is previously engaged with the gear 36 present at the rear end of the input main shaft 23, so that the front hollow shaft 37
The rotational power of the input main shaft 23 is transferred to both countershafts 3 without being affected by the assembly work between a, 38a and the rear solid shafts 37b, 38b.
The transmission gear 36 common to both the countershafts 37 and 38 allows the transmission to be properly distributed and transmitted to both the countershafts 37 and 38 at all times.

Further, the front hollow shafts 37a, 38a of both countershafts 37, 38 are formed identically, and furthermore, the front hollow shafts 37a, 38a of both countershafts 37, 38 are formed identically.
Since the gears 39 and 50 on 38a are also set to be the same, they are spline-fitted to the front hollow shafts 37a and 38a of both countershafts 37 and 38 for travel and PTO transmission. The gears 39, 50 can be used interchangeably between the countershafts 37, 38, and in this sense, the mass production effect can be maximized. Since it is possible to further improve the balance effect in terms of the overall arrangement with 23 and the space-saving effect in terms of installation, it can be said that this is extremely beneficial, especially in downsizing the tractor.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic side view of the tractor according to the present invention, and Figs. 2 and 3 are the - lines and - of Fig. 1.
Fig. 4 is an enlarged sectional plan view showing the transmission mechanism developed, Fig. 5 is a side sectional view schematically showing the conventional mechanism, and Fig. 6 is a front cross-sectional view. It is a diagram. T...Tractor body, S1...Clutch housing, S2...Transmission case, H
... Interval height, X, Y, Z ... Vertex of virtual triangle, 10 ... Engine, 11 ... Crankshaft, 16 ... Floor, 20 ... Step, 23
...Input main shaft, 27...Clutch, 3
7... Countershaft for traveling speed change, 38...
PTO shifting countershaft, 23a, 37
a, 38a...Hollow shaft, 37b, 38b...Solid shaft, 36, 39, 50...Gear.

Claims (1)

[Claims for Utility Model Registration] An input main shaft 2 to which the rotational power of the engine 10 is intermittently received via a clutch 27.
3 and both countershafts 37 and 38 for traveling transmission and PTO transmission, which are transmitted from the main shaft 23, to the top vertex X that defines the virtual isosceles triangle. The countershafts 37 and 38 are located below the rotational axis of the crankshaft 11, and the left and right countershafts are equally distributed, located at the remaining two vertices Y and Z of the virtual isosceles triangle, so that the shafts are parallel to each other. In a tractor transmission mechanism constructed by a rack, the rear part of the input main shaft 23 is bearingly supported by an intermediate partition wall 24 of the clutch housing S1, and the main shaft 23 faces into the gear chamber 15 divided by the partition wall 24. A transmission gear 36 for distributing transmission to both countershafts 37 and 38 is integrally fixed at the rear end, and both countershafts 37 and 38 are pivotally mounted in the gear chamber 15 of the clutch housing S1. The front hollow shafts 37a and 38a are each formed from mutually identical front hollow shafts 37a and 38a, and rear solid shafts 37b and 38b that are mounted in a transmission case S2 that is assembled from the rear to the clutch housing S1, and the front hollow shafts 37a and Mutual identical gears 39, 50 each splined onto 38b
is maintained in a transmission state in which it constantly meshes with the distribution transmission gear 36 of the main shaft 23, while the rear solid shafts 37b, 38b are spline-fitted to the front hollow shafts 37a, 38a, both inserted from the rear. A tractor transmission mechanism characterized in that both countershafts 37 and 38 are directly connected to each other as a whole.