JPS61263832A - Speed change gear for farm tractor - Google Patents

Abstract

PURPOSE:To make plural transmission shafts possible to be housed in a narrow space, by setting up shafts, which are set up in a transmission case parallelly in a longitudinal direction and transmits an engine speed to a differential gear mechanism upon gearshifting, in a loop form at a sectional view in the longitudinal direction. CONSTITUTION:As for shafts housed inside a transmission case for a farm tractor and supported by bearings, there are an input shaft 1, a counter shaft 2, a hydraulic clutch shaft 3, a subtransmission shaft 4, a pinion shaft 5 and a power takeoff shaft 6. In this case, these shafts 1-5 are connected with their own axial cores whereby they are set up in a loop form so as to describe a side-long oblong. And, the PTO shaft 6 is set up in central part of the transmission case 9 at an upper part of the input shaft 1. With this constitution, height in a vertical direction ranging from the input shaft 1 to the pinion shaft 5 is lowered as compared with the conventional one, while a step part corresponding to a position where an operator puts his feet is formable into being flat.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention is for use in a transmission for agricultural tractors, in which the height of the transmission case is lowered to make the part where the operator's feet are flat. It concerns the arrangement of the axes.

(B) Prior art The transmission case of conventional agricultural tractors is usually seated by an operator who rides on it, straddling it, and when viewed in cross section in the front-rear direction, it has a rectangular shape that is long in the vertical direction. .

For example, see Utility Model Application No. 58-188224.

(C) Problems to be Solved by the Invention The object of the present invention is to provide a step-through structure in which the left and right steps are connected by a flat surface so that the operator seated in the seat can drive with his or her feet aligned. be. In order to do this, it is necessary to change the mission case from one that is long vertically to one that juts out from side to side.
It is also necessary to change the arrangement of each gear shift shaft inside the transmission case.

The present invention provides an optimal arrangement of the transmission shaft when the transmission case is made to extend laterally.

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

It is arranged in parallel in the longitudinal direction inside the transmission case of an agricultural tractor, and the shaft from the input shaft to the pinion shaft is arranged in a loop shape when viewed in cross section in the longitudinal direction, and changes the speed of the engine rotation and transmits it to the differential gear device. It is.

(E) Embodiment The object and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

Fig. 1 is an overall side view of the agricultural tractor of the present invention, Fig. 2 is a sectional side view of the vicinity of the clutch housing, and Fig. 3 is a sectional view of the transmission case attached to the clutch housing, when the transmission is a hydraulic clutch type transmission. 4 is a rear sectional view of the clutch housing and transmission case, FIG. 5 is a side sectional view of a transmission case equipped with a hydraulic clutch type transmission, and FIG. 6 is a rear sectional view of the transmission case. FIG. 7 is a front view of the center plate.

In FIG. 1, B is a bonnet in which the engine is placed. A clutch housing 51 is attached to the rear surface of the engine. A transmission case 50 is further attached to the rear surface of the clutch housing 51. The position of the engine and clutch housing 51 in the transmission case 50 is higher than the position of the step S of the agricultural tractor, and if the shaft were directly extended from here to the transmission case 9, the clutch shaft would pass through the position of the operator's foot. Therefore, since there is no step-through configuration, the clutch shaft and the step S are configured not to interfere with each other by changing the speed within the transmission case 50 and lowering the position of the shaft one step.

As shown in FIG. 2, FIG. 3, and FIG. Even when a transmission is installed, the same transmission case 50 can be used.

Flywheel 5 at the rear end of the engine crankshaft
9 is fixedly installed, and a main clutch device Tl7160 is disposed on the rear surface of the flywheels 5 and 9 so as to be able to connect and disconnect power. The main clutch device 60 is connected and disconnected by rotating a shaft 67 using a wire 68 and by sliding a clutch release bearing 61 on the clutch shaft 58 using an arm 62.

When driving the HST type transmission in the mission case 9 as shown in FIG. 2, power is directly transmitted from the gear 52 to the gear 53 and the universal joint shaft 55 is driven from the shaft 54.

In addition, when a hydraulic clutch type transmission is disposed inside the transmission case 9, another shaft 66 is inserted between the shafts 58 and 54 in the transmission case 50, as shown in FIG. , a rotation opposite to that in the HST type transmission is transmitted thereon via a reverse gear 64. The reason why the rotation direction is different between the H3T type transmission and the hydraulic clutch type transmission is that the height of the mission case 9 needs to be lowered in order to step through, and for that reason, conventionally The differential ring gear of the differential gear device was placed on the left side of the pinion gear, but it must be placed in the opposite direction, and in the case of a hydraulic clutch type transmission,
Although it was possible to reverse the direction of rotation using a gear train in the middle, the HST type transmission had a fixed direction of rotation and could not be changed.

As shown in Figure 2, the shape of the transmission case is different between the HST type transmission and the hydraulic clutch type transmission (because the shape of the transmission case is different, the position where the input shaft and universal joint shaft 55 are connected is also different). The position of the input shaft 56 in the HST type transmission is at the front, and the position of the pump shaft 14 in the case of the hydraulic clutch type transmission is at the rear.

Next, the configuration of the hydraulic clutch type transmission will be explained with reference to FIGS. 5, 6, and 7.

The transmission case 9 of this gear is not connected to the clutch housing 51 like the transmission case of a conventional tractor, but is supported separately.

A center plate 8 is attached to the front surface of the mission case 9, and a hydraulic pump device 11 and a seal case 13 are further attached to the front surface of the center plate 8. The structure of the center plate 8 is as shown in FIG. 7, and a delay relief valve device 47 and a control valve 46 are fitted therein.

Conventionally, the front wheel drive shaft 10 was generally arranged at the bottom of the transmission case, but in the present invention, it is arranged immediately next to the input shaft 1.

The input shaft, counter shaft 2, hydraulic clutch shaft 3, auxiliary transmission shaft 4, pinion shaft 5, and PTO shaft 6 are arranged in a loop to form a horizontally long ellipse when their axes are connected. There is.

In particular, the PTO shaft 6, which conventionally usually protrudes from below the rear surface of the mission case, is arranged above the input shaft 1b and in the center of the mission case. The first half of the drawing in FIG. 5 shows a drawing developed following the axis, so it cannot be used as a reference for the arrangement of the axis. The arrangement of the shafts is precisely shown in FIGS. 6 and 7.

Based on FIG. 5, the configuration of the hydraulic clutch type transmission will be explained in the order of power transmission.

The input shaft 1 is connected to the rear end of the pump shaft 14, and power is transmitted from the gear 15 of the input shaft 1 to the gear 16 of the counter shaft 2. In addition, three gears 18, 19, and 20 are fixedly installed on the counter shaft 2, and the hydraulic clutch shaft 3
It meshes with the upper loose fit gears 17, 21, 22, and 23.

A reversing gear is interposed between the gear 20 and the loosely fitted gear 23, forming a gear train for reverse speed.

The four sets of gear trains are connected to hydraulic clutch devices C1, C2, C3,
By selectively engaging C4, the gears are brought into engagement and the main shift is performed.

The rotation of the hydraulic clutch shaft 3 is controlled by the gear 30.
The transmission is transmitted to the gear 24, and the sub-shift is performed in three stages between the sub-shift shaft 4 and the pinion shaft 5.

The gears 24, 25, 26 on the sub-shift shaft 4 and the gears 29, 27, 28 on the pinion shaft 5 engage with each other to perform high, medium, and low gear shifts. The gears 27 and 28 are constructed as an integral sliding gear, and the sliding of the sliding gear selects among the three sets of gear trains. The rotation of the pinion shaft 5 is connected to and disconnected from the front wheel drive shaft 10 via the clutch device 49. The clutch device 49 is moved back and forth by a front wheel drive clutch lever shaft 45 as shown in FIG.

Also, a creep speed that is even slower than the speed of the secondary transmission is obtained by sliding the sliding gear 28 further rearward. That is, the creep reduction shaft 3 is connected to the gear 26 on the sub-transmission shaft 4.
Gear 37 on top of 8 is meshed, and gears 39, 41, 40
The super-decelerated rotation is transmitted to the pinion shaft 5 by the meshing of the sliding gear 28 with the gear 40.

The rotation after being shifted on the PTO shift shaft 7 is transmitted to the PTO shaft 6 . The PTO transmission shaft 7 is arranged on the same axis as the input shaft 1. Gear 31 on PTO transmission shaft 7
32 and the gears 18 and 19 on the counter shaft 2 are always in mesh with each other, and by selectively engaging the two sets of gears by the PTO shift slider 35, the PTO shift is performed.

The rotation after shifting in the PTO transmission is from the gear 33 to the PTO transmission.
It is transmitted to the gear 34 on the TO axis 6. The PTO shaft 6 passes above the differential gear device 12 and projects rearward from the rear surface of the mission case 9.

In Fig. 6, 44 is the PTO gear shift lever shaft, and 36 is the PTO gear lever shaft.
It is a TO transmission shifter and moves the PTO transmission sliding body 35 back and forth.

Reference numeral 43 denotes an auxiliary transmission lever shaft, which allows the auxiliary transmission shifter 42 to slide the sliding gears 27 and 28 back and forth.

(f) 0 Functions and Effects The configuration of the present invention is as described above. Next, the functions and effects of this configuration will be explained.

First, in the present invention, the shaft from the input shaft to the pinion shaft, which changes the speed of the engine rotation and transmits it to the differential gear device, is arranged in a loop shape in a longitudinal cross-sectional view. The vertical height of the can be made smaller than before. The conventional layout of the shafts inside the transmission case of a tractor was such that the input shaft was located at the top, the speed was gradually changed as the shaft moved down the shaft, and the pinion shaft was configured on the lower shaft, so the transmission case was inevitably elongated. However, in the mission case of the present invention, by arranging each axis in a loop that rotates once, it is possible to fit five or more axes from the input axis to the nion axis within a narrow space. This is what was created.

Second, by configuring the mission case as described above, the step part where the operator places his/her feet can be made flat, allowing the operator to drive in a posture without fatigue, and the lowest ground level of the tractor. The height could be raised, and the front height could be lowered, making it possible to carry out technical work in orchards. This also improves stability as an agricultural tractor.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of the agricultural tractor of the present invention, Fig. 2 is a sectional side view of the vicinity of the clutch housing, and Fig. 3 is a sectional view of the transmission case attached to the clutch housing, when the transmission is a hydraulic clutch type transmission. 4 is a rear sectional view of the clutch housing and transmission case, FIG. 5 is a side sectional view of the Mitsushiron case equipped with a hydraulic clutch type transmission, and FIG. 6 is a rear sectional view of the transmission case. FIG. 7 is a front view of the center plate. 1...Input shaft 2...Counter shaft 3...Hydraulic clutch shaft 4...Sub-shift shaft 5...Pinion shaft 6...PTO shaft 7...PTO shift shaft 9...Mission Case applicant Yanmar Diesel Co., Ltd. Agent Patent attorney Toshibe Yano Figure 6

Claims (1)

[Claims] Arranged in parallel in the front-rear direction inside the transmission case of an agricultural tractor, the shaft from the input shaft to the pinion shaft is arranged in a loop shape in a cross-sectional view in the front-rear direction, and changes the speed of the engine rotation and transmits it to the differential gear device. A transmission for agricultural tractors featuring: