JPS6359885B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is directed to reducing the vertical height of a transmission chamber A, which is composed of a rear transmission case of a clutch housing of an agricultural tractor, a rear axle case, etc. This eliminates the protruding part under the feet of the operator sitting in the seat, and also eliminates the gear shift levers.By installing them on the side of the case, the step part is widened, and the riding position is changed from the straddling position of a conventional tractor. It allows you to ride in a step-through mode like a scooter.

(b) Prior Art Conventionally, it has been known that an input shaft is provided protrudingly supported in a transmission case in a cantilevered state, and a main transmission is configured by shafts arranged on the left and right sides below the input shaft. It is.

For example, Utility Model Publication No. 53-4581 and Utility Model Publication No. 57-
This is similar to the technology described in Publication No. 20410.

(c) Problems to be solved by the invention In a tractor, the diameters of the front and rear tires are almost determined, and the heights of the front axle and rear axle that support them are also determined from the beginning. We are being affected by this.

Once the heights of these two positions, front and rear, are determined,
The line connecting the two positions is also determined.

Furthermore, since the height of the seat is determined by regulations for small special vehicles, the position of the seat's feet is also determined by the relationship with the upper surfaces of the front axle and rear axle.

Under these regulations, the only way to create a step-through configuration is to reduce the height of only the transmission case, clutch housing, and rear axle case and widen them laterally.

Furthermore, since the height of the engine is determined by its relationship to the front axle, the height of the main clutch device and the distance from the clutch shaft to the input shaft must be approximately the same height as the engine crankshaft.

As a result, the position of the input shaft is determined, so the height of the transmission case can be lowered by leaving the input shaft as it is and lowering the height of the shafts of the subsequent main transmission, auxiliary transmission, and PTO transmission. It is possible.

Further, in order to bulge out in the width direction, it is necessary to arrange the shafts on the left and right instead of the top and bottom, and in the present invention, the main shaft and counter shaft are arranged on the left and right below the input shaft. Further, by keeping the upper surfaces of the clutch housing and transmission case low, step-through is made possible.

Further, according to the present invention, it is possible to eliminate obstacles in the step portion while maintaining the same strength and ground clearance.

(d) Means for Solving the Problems The objects of the present invention are as described above, and the configuration for achieving the objects will now be explained.

Main transmission, auxiliary transmission, PTO in transmission room A
In a structure in which a transmission is provided, an input shaft 11 that transmits power from an engine E into a transmission chamber A is cantilever-supported on the front wall of the transmission chamber A and protrudes into the transmission chamber A. is the topmost shaft in the transmission chamber A, and the main transmission, auxiliary transmission, and PTO transmission are
A main transmission device is disposed on a shaft other than the input shaft 11 and below the input shaft 11, and which first changes the speed of the rotation of the input shaft 11. The main shaft 12 and counter shaft 13 are arranged on the left and right sides below the input shaft 11, and a fixed gear 15 is fixed to the rear end of the input shaft 11, and a double loosely fitted gear 16 is loosely fitted to the front end of the lower main shaft 12. ,1
7 are meshed with each other, and the two loosely fitted gears 16, 17
The other side of the countershaft 13 and the main shaft 1 are meshed with a fixed gear 23 fixed to the front end of the countershaft 13.
The auxiliary transmission is placed behind the main transmission, which is placed between the two.

(E) Embodiments The object and structure of the present invention are as described above, and next, the structure for achieving the object will be explained.

Figure 1 is an overall side view of the agricultural tractor, Figure 2 is a sectional side view of the clutch housing, transmission case, and rear axle case, Figure 3 is an enlarged sectional view of the rear side of the clutch housing, and Figure 4 is the rear axle. It is a rear sectional view of a case part.

In FIG. 1, a clutch housing 1 is fixedly installed on the rear surface of an engine E.
A transmission case 2 is fixed to the rear surface with a center plate 57 in between, and a rear axle case 3 is fixed to the rear surface of the transmission case 2.

On the left side of the rear axle case 3, there is a PTO switching lever 4, a sub-shift lever, a front wheel drive clutch lever,
The PTO gear lever, etc. protrude, and the creep gear lever, PTO clutch lever, etc. protrude from the right side of the rear axle case. 6 is a PTO axis, and 5 is a lift arm.

It is an object of the present invention to provide a step-through by keeping the step position clear of obstructions when the operator sits on the seat 65.

The power transmission system will be explained with reference to the drawing in FIG.

The rear part of the clutch housing 1, the transmission case 2, and the rear axle case 3 constitute an oil bath type transmission chamber A. The rotation of the engine E is transmitted to the fixed gear 15 from the input shaft 11 via the main clutch device within the clutch housing 1.

The fixed gear 15 rotates through two loosely fitted gears 16 and 17.
to the fixed gear 23 on the counter shaft 13.

Fixed gears 24, 2 are mounted on the counter shaft 13.
5 and 26 are provided, and the fixed gear 25 is transmitted to the loose-fit gear 18 on the main shaft 12, and the fixed gear 26 is transmitted to the loose-fit gear 20 on the main shaft via the reversing gear 19.

The aforementioned double loose fit gear 17 is a hydraulic clutch device 2.
It also serves as the drive gear for 1a. Hydraulic clutch devices 21a and 21b on the main shaft 12 change the forward speed to 2nd speed and 1st speed, and the hydraulic clutch device 22 changes the main speed to reverse.

By selecting the hydraulic clutch devices 21a, 21b, 22, the main shaft 12 is subjected to a main speed change. The rotation after the main gear shift is controlled by the hydraulic clutch devices 38a, 3
8b, the main gear is shifted to low or high.

When the hydraulic clutch device 38a is "engaged", a low speed of the main shift can be obtained.

That is, the rotation of the main shaft 12 is controlled by the hydraulic clutch device 38a.
From fixed gear 39, fixed gear 35a, detour shaft 3
5, the fixed gear 35b, the fixed gear 40, and the shaft 70.

Also, due to the "engagement" of the hydraulic clutch device 38b,
Power is directly transmitted from the main shaft 12 to the fixed gear 40 via the hydraulic clutch device 38b, resulting in high speed.

The shaft 70 and the shaft 12 are aligned on the same axis, and a detour shaft 42 is also provided at this connecting portion, and the speed is changed into two stages: creep speed and normal speed.
Creep shifting is performed by sliding the sliding gear 44 back and forth by the shifter 71.

That is, the sliding gear 44 is slid forward, and the detour shaft 4
When meshing with the fixed gear 41 on 2, the detour shaft 42,
The deceleration rotation is transmitted from the installed gear 42a to the fixed gear 72 on the shaft 36.

When the sliding gear 44 is moved backward, the shaft 43 and the shaft 36 are integrally connected and the speed becomes normal.

A sub-shift is performed between the shaft 36 and the pinion shaft 37. High speed is obtained by the sliding gear 48 meshing with the fixed gear 45 on the shaft 36, and the sliding gear 48
By integrating with the loose fit gear 47, a low speed can be obtained.

PTO shifting is performed between the counter shaft 13 and the PTO shifting shaft 14.

Fixed gears 23, 24, 2 on counter shaft 13
5, 26 and the loosely fitted gear 27 on the PTO transmission shaft 14,
28, 29, and 30 are always in mesh with each other, and PTO shifting is performed by sliding sliders 75 and 76.

The rotation of the PTO transmission shaft 14 is the shaft 77, shaft 10,
It is transmitted to the PTO shaft 6 via the PTO clutch device.

The sliding gear 9 is a switching gear between the ground PTO and the normal PTO, and when the sliding gear 9 is moved forward and the shafts 77 and 10 are integrated, the normal PTO is switched.
rotation, and the internal gear 5 is rotated by retracting the sliding gear 9.
3, the driving rotation is transmitted from the pinion shaft 37 to the fixed gears 50 and 51 while being reduced in speed, and becomes the ground PTO.

A fixed gear 54 on a shaft 78 is always meshed with the fixed gear 52, and the rotation of the front wheel power take-off shaft 31 is "disconnected" or "engaged" by the sliding of the clutch shifter 55.
do.

The main transmission has 1st and 2nd forward speeds, a first stage for reverse speed, and a second stage that changes the rotation speed after the previous stage is shifted to higher or lower speeds, both of which are comprised of hydraulic clutch type transmissions.

This main transmission for the front and rear gears ultimately allows for four forward motions.
It can be shifted to 6 gears, including 2 reverse gears and 2 reverse gears. All gear changes by this main clutch device are performed by a hydraulic clutch type transmission, so the spool of the hydraulic control valve for front-stage operation and the spool of the hydraulic control valve for rear-stage control are placed side by side, so that one main shift lever can be operated. It is configured to be able to change gears into four forward speeds and two reverse speeds by rotating back and forth.

The hydraulic control valve device V is made small and installed at the front of the clutch housing, etc., and the main gear shift lever M is installed on the dash board surface under the steering handle, so that the hydraulic control valve and the main gear shift lever do not protrude into the step-through section. I have to.

Further, three sets of hydraulic clutch devices 21a, 21b, 22 at the front stage of the main transmission and two sets of hydraulic clutch devices 38a, 38b at the rear stage are also provided on the main shaft 12,
A seal case 32 is provided above the center of the main shaft 12, with its central portion supported by a bearing on a center plate 57.
Power is transmitted from the outer peripheral oil passage 12a to five hydraulic clutch devices at the front and rear.

Further, a hydraulic pump 33 is provided on the center plate 57, and the hydraulic pump is driven by the counter shaft 13. The pump case of the hydraulic pump 33 is extended to the front end of the detour shaft 35, and the extension of the shaft 13 and the detour shaft 35 are connected via a one-way clutch 34, so that when the engine is stopped, the rear wheel The rotational force of the engine is configured so that it passes through the hydraulic clutch device and directly reaches the engine.

As shown in FIGS. 2 and 3, in the present invention, the input shaft 11 that protrudes rearward from the height of the crankshaft of the engine E is supported in a cantilever manner by the part that protrudes into the transmission chamber, and is placed at the top of the transmission chamber. The rear axles are the main shaft 12, the shaft 43, the shaft 36, the counter shaft 13, the detour shaft 35, the pinion shaft 37, the PTO transmission shaft 14, the shaft 77, the shaft 10, the PTO shaft 6, the front wheel,
A power output shaft 31 and the like are provided below the input shaft 11.

As shown in FIG. 4, only the detour shaft 42 for creep shifting can be mounted at a position approximately at the same level or slightly lower than the input shaft 11.

Further, as shown in FIG. 4, a main shaft 12 and a counter shaft 13 are provided below the input shaft 11 and at the apexes of the base of the triangle on the left and right, and the input shaft is connected to the transmission chamber A.
Since it only protrudes in a cantilevered manner from the front end of the gearbox, from then on, the main shaft 12 and counter shaft 13 lined up on the left and right are the uppermost shafts, and the height of the transmission chamber is lowered and the width is increased. -ing

In addition, the operating levers are also provided on the side of the case to prevent obstacles from protruding from the top. 60 is a gear shift lever shaft for sub-shift, 60a is an arm, 60
b is a speed shifter. 61 is a PTO switching lever shaft, 61a is an arm, and 61b is a PTO switching shifter.

62 is a front wheel drive clutch lever, and 62a is its arm. 63 is the PTO clutch lever shaft,
63a is an arm.

71a is a creep speed change lever shaft, 71b is an arm, and 71 is a speed change shifter.

The gear shifter shaft 71a is fixed to a lid 69 of a creep gear shift kit that supports a creep gear set, and by attaching the lid 69, the shifter shaft 71a can be removed together with the gear shifter 71.

The PTO clutch device is composed of a clutch case 7, a friction plate device 8, and a spline body 80 that meshes with the inner peripheral spline of the clutch case.The clutch case 7 is moved back and forth by a link device that interlocks with the lift arm 5, and power is disconnected.

When connecting and disconnecting, the friction plate type clutch first connects and disconnects, and then the meshing type clutch connects and disconnects.

(F) Effects of the Invention Since the present invention is configured as described above, it has the following effects.

First, it is no longer necessary to provide a transmission with shafts arranged above and below an input shaft that coincides with the engine's crankshaft axis, as in the past.

That is, in the present invention, the input shaft is cantilevered just by inputting power into the transmission chamber, and then the speed is changed between the shafts below it, so the upper surface of the part where the operator's step will be placed after this is cut off. This made it possible to lower the height and create a step-through configuration.

Also, there is a step 1 from the rear of the clutch housing 1.
A was provided to lower the height, and a step 3a was provided from the front end of the rear axle case 3 to return it to its original height.

Second, a main transmission device that first changes the rotation of the input shaft is provided between the main shaft below the input shaft and the counter shaft, and the main shaft 12 and the counter shaft 13 are arranged on the left and right sides below the input shaft. Therefore, after the input shaft is cantilevered and interrupted, the upper surface formed by the main shaft 12 and counter shaft 13 can be removed, and the part beyond that can be removed, creating a wide transmission chamber A with a flat upper surface. This makes it possible to create a step-through transmission with the same strength as conventional transmissions.

Thirdly, the fixed gear 15 fixed to the rear end of the input shaft 11 is meshed with one of the two loosely fitted gears 16 and 17 loosely fitted to the front end of the lower main shaft 12, and the two loosely fitted gears are engaged with each other. By meshing the other of 16 and 17 with a fixed gear 23 fixed to the front end of the counter shaft 13, the rotation input from the input shaft 11 to the main transmission can be reduced in two stages with a large reduction ratio. This makes it possible to reasonably reduce the reduction ratio of the subsequent transmission, and to reduce gear noise mainly in the rotating main transmission.

Fourth, by arranging the main transmission between the counter shaft 13 and the main shaft 12, and arranging the width transmission behind the main transmission, the vertical dimensions are reduced to the extent that step-through is possible. It was possible to do that.

[Brief explanation of drawings]

Figure 1 is an overall side view of the tractor, Figure 2 is a side sectional view of the transmission chamber A consisting of the clutch housing, transmission case, and rear axle case, and Figure 3 is an enlarged side sectional view of the clutch housing. FIG. 4 is a rear sectional view of the rear axle case portion. A... Gearbox, E... Engine, 11... Input shaft, 12... Main shaft, 13... Counter shaft, 15
...Fixed gear, 16, 17...Two loose fitting gears, 2
3...Fixed gear.

Claims (1)

[Claims] 1 Main transmission, auxiliary transmission,
In a structure equipped with a PTO transmission, the input shaft 11 transmits power from the engine E into the transmission chamber A.
is cantilever-supported on the front wall of the transmission chamber A and protrudes into the transmission chamber A, and the input shaft 11 is the uppermost shaft in the transmission chamber A, and the main transmission, sub-transmission, and PTO transmission are connected to each other. is arranged on a shaft other than the input shaft 11 and below the input shaft 11, and a main transmission device that first changes the speed of the rotation of the input shaft 11 is connected to the main shaft 1 below the input shaft 11.
A fixed gear 15 is provided between the main shaft 12 and the counter shaft 13, the main shaft 12 and the counter shaft 13 are arranged below the input shaft 11 on the left and right, and the fixed gear 15 is fixed to the rear end of the input shaft 11.
and a fixed gear in which one of two loosely fitted gears 16 and 17 that are loosely fitted to the front end of the lower main shaft 12 is meshed, and the other of the two loosely fitted gears 16 and 17 is fixed to the front end of the counter shaft 13. 23 and counter shaft 1
A transmission device for an agricultural tractor, characterized in that a sub-transmission device is arranged behind a main transmission device arranged between a main shaft 12 and a main shaft 12.