JPS6058045B2 - Agricultural tractor transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a traveling system transmission mechanism that can easily achieve a normal traveling speed suitable for rotary work and an extremely low traveling speed suitable for falcon work. The present invention relates to an agricultural tractor having a transmission device interposed therein that can be switched between a super deceleration state and other speed change states.

In the transmission mechanism of this type of agricultural tractor, when a running load above a certain level is applied during work at normal running speeds, such as rotary work, the abnormal load is transmitted to the engine via the running system transmission mechanism. In other words, the abnormal load mentioned above can be effectively absorbed by stopping the operation of the engine.In other words, the engine can function as a torque limiter against abnormal loads during work at normal running speeds. Therefore, there is no need to provide a special torque limiter mechanism, and the transmission mechanism can be simplified. As a result, the above-mentioned abnormal load does not affect the engine,
In other words, the engine can also function as a torque limiter, which may damage the gears between the transmission and the axle.

In addition, in order to prevent damage to the transmission mechanism and parts due to abnormal loads during driving operations in such super-deceleration conditions, if the entire transmission system is configured to transmit a large amount of torque, the entire device will become larger and the cost will increase. . In view of the above-mentioned circumstances, the present invention reliably prevents damage to gears, etc. caused by abnormal load when the transmission is in a super-deceleration state, without increasing the size of the device or increasing costs. In the above-mentioned system, the front end of the transmission shaft interposed in the traveling system transmission mechanism, and the transmission shaft externally fitted rotatably sun gears with different numbers of teeth are respectively connected to the front end of the cylindrical member, and a support shaft that rotatably supports a planetary gear that is interlockingly connected to the sun gear is arranged in a direction in which the power is transmitted relative to the transmission shaft. The first support member is connected to the rear end of the output shaft on the upper side of the cylindrical member, and the second support member is rotatably fitted onto the outside of the cylindrical member. A transmission member capable of sliding only in one direction is provided, and an engaging portion for producing a transmission state other than the super deceleration state is provided between the transmission member and the second support member, and a fixed portion between the transmission member and the aircraft body is provided. are each provided with an engagement structure that fixes the movement of the transmission member to create a super deceleration state, and the engagement structure is configured to be able to rotate together when engaged with the transmission member, and is normally elastic. A restrictor is provided using an elastic member that prevents the engaging structure from rotating together by applying a pressing force, and allows the engaging structure to rotate together against the elastic pressing force when the load exceeds a certain level. Features.

That is, according to the present invention, when a running load of a certain level or more is applied during work in which the transmission is in a normal speed change state other than a super deceleration state, this difference occurs.

In addition to being able to effectively absorb normal loads by stopping the engine, when a running load above a certain level is applied while the transmission is in a super-deceleration state, it is safe to operate based on this abnormal load. By the action of the clutch, in other words. The engagement structure provided on the fixed wall rotates idly against the elastic pressing force of the restrictor and rotates together with the switching member, thereby automatically disconnecting the transmission, which makes it possible to automatically cut off the transmission during super-deceleration traveling work. Damage to transmission parts such as gears due to abnormal loads can be reliably avoided.Moreover, by simply incorporating a safety clutch, the entire transmission system must be constructed to ensure high torque transmission. Because of this, the entire device is relatively small and easy to construct economically, yet the safety effect against abnormal loads as described above can be achieved. In particular, in the present invention, since the engagement structure for fixing the movement of the transmission member and switching and maintaining the planetary reduction gear in the super-deceleration state is structured to double as a safety clutch, the device can be miniaturized. This has the advantage of being able to contribute even more to the Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an agricultural tractor, which is equipped with a transmission case 3 directly connected to an engine 1 via a cylindrical frame 2, a driver's seat 4 and a driving rear wheel 5, and a lower frame 6 on which the engine 1 is mounted. A bonnet 8 is provided with driving front wheels 7 for steering and covers the circumference of the engine 1.
A steering handle 9 for steering the driving front wheels 7 via a steering device (not shown) is provided at the rear end.

The internal structure of the mission case 3 is constructed as shown in FIG. That is, among the transmission spaces 3A, 3B, and 3C divided into three in the longitudinal direction of the aircraft, the propulsion shaft 10 driven by the engine 1 and the output shaft 11 of the traveling system transmission mechanism are located in the front space 3A. The output shaft 12 of the working device system transmission mechanism is mounted parallel to each other, and a hydraulic clutch 1 is installed between the propulsion shaft 10 and the traveling system output shaft 11.
3... by selectively entering and operating the output shaft 11.
A transmission device 14 is provided which can change the speed of the drive to three forward speeds and one reverse speed, and a PTO shaft mounted in the rear space 3C is provided between the propulsion shaft 10 and the work equipment system output shaft 12. 1
Transmission device 16 capable of changing the rotation speed of 5 into 3 steps
has been established.

Further, in the central space 3B, there is provided a first intermediate transmission shaft 17 that rotates about the same axis as the traveling system output shaft 11, and this shaft 1.
A second intermediate transmission shaft 18 having a gear 18A that is always engaged with a gear 17A fixed to the gear 7, a fat mechanism 19 for the drive rear wheel 5 provided in the rear space 3C, and a transmission case 3.
A bevel pinion shaft 21 that transmits power to the front wheel drive shaft 20 protruding forward from the front wheel drive shaft 20 is mounted between the rear end of the traveling system output shaft 11 and the front end of the first intermediate transmission shaft 17. A planetary speed reduction device 22 that can be freely switched between an active position and a non-active position that produces a super-deceleration state is arranged, and this planetary speed reduction device 22 and the transmission 14 with the hydraulic clutch 13 are arranged.
The transmission device 2 is capable of switching freely between a super deceleration state and a high speed state.
3, and the transmission device 23 includes a safety clutch 24 at the rear end of the first intermediate transmission shaft 17 for automatically cutting off transmission when a load above a certain level is applied. It is provided in such a way that it only works when the condition is present.

A transmission 25 is provided between the second intermediate transmission shaft 18 and the bevel pinion shaft 21, which can change the speed of the bevel pinion shaft 21 into two high and low stages. PTO transmission shaft 2 installed across
6, the power from the working device system output shaft 12 is transferred to the PTO
A synchronization clutch 27 is provided that can be switched between a first state in which the transmission is transmitted to the shaft 15 and a state in which the PTO shaft 15 is synchronized with the bevel pinion shaft 21 of the traveling system.

The planetary reduction gear 22 is constructed as shown in FIGS. 3 and 4.

That is, sun gears 29A and 29B having different numbers of teeth are connected to the front end of the first intermediate transmission shaft 17 and the front end of a cylindrical member 28 rotatably fitted thereon.
A support shaft 31 that rotatably supports a planetary gear 30 that is interlocked with 9A and 29B is rotated by the first support member 32 spline-fitted to the rear end of the traveling system output shaft 11 and the cylindrical member 28. The spline portion 2A of the cylindrical member 28 is fitted with a dock claw 33a formed at the rear end of the second support member 33. A transmission member 34 having a docking claw 34a that can be engaged and a docking claw 34b that can be fitted and engaged with the docking claw 24a of the safety clutch 24 held in the transmission case 3 side is slidably fitted on the outside. , by shifting the speed change member 34 in the axial direction of the cylindrical member 28 and engaging it with the dock claw 33a of the second support member 33 or the dock claw 24a of the safety clutch 24, the first intermediate transmission shaft 17 a high-speed state in which the traveling system output shaft 11 rotates at the same speed as the traveling system output shaft 11, and a super-deceleration state in which the first intermediate transmission shaft 17 is rotated by the difference in the number of teeth between the sun gears 29A and 29B during one rotation of the traveling system output shaft 11. It is configured to switch.

The safety clutch 24 is constructed as follows.

That is, the clutch plate 2 on which the dock pawl 24a is formed
4A is attached to the transmission case 3 side so as to be rotatable around the axis of the first intermediate transmission shaft 17, and a lockable lock that can be engaged with a recess 24b formed on the outer periphery of the clutch plate 24A. Rotation regulating arm 2 with protrusion 24B
4C is configured to be swingable around an axis parallel or substantially parallel to the axis of the first intermediate transmission shaft 17, and between the free end of the rotation regulating arm 24C and the transmission case 3,
A spring 24D that presses and biases the rotation regulating arm 24C toward the clutch plate 24A side is interposed, so that when the transmission 23 is in a starting/decelerating state, a load above a certain level, in other words, the first load is applied to the wheel. When a load above a certain level is applied to the intermediate transmission shaft 17, the clutch plate 24A is rotated idly against the biasing force of the spring 24D, thereby reducing the transmission of power from the traveling system output shaft 11 to the first intermediate transmission shaft 17. It is configured to cut off automatically.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the transmission mechanism for an agricultural tractor according to the present invention, in which Fig. 1 is an overall side view of the agricultural tractor, Fig. 2 is a schematic side view showing the transmission system of the main part, and Fig. 3 is the main part. FIG. 4 is an enlarged rear view of the main parts. 3...Fixed part of the fuselage, 11...Output shaft, 13...Hydraulic clutch, 14...Transmission device, 17...Transmission shaft , 22... Planetary reduction gear, 23... Transmission, 24... Safety clutch, 24A... Engagement mechanism, 24C...
...Restrictor, 24D...Elastic member, 28.
... Cylindrical member, 29A, 29B ... Sun gear, 30 ... Planet gear, 32 ... First support member, 33 ... Second Support member, 34...
...speed change member, 33a, 34a...engaging portion.

Claims (1)

[Claims] 1. In an agricultural tractor in which a transmission device 23 that can freely switch between a super deceleration state and other speed change states is interposed in the traveling transmission mechanism, the front end of the transmission shaft 17 interposed in the traveling transmission mechanism. Sun gears 29A, 29B having different numbers of teeth are connected to the front end of a cylindrical member 28 which is rotatably fitted onto the transmission shaft 17, respectively.
A first support member 3 in which a support shaft 31 that rotatably supports a planetary gear 30 interlockingly connected to the transmission shaft 17 is connected to the rear end of the output shaft 11 on the upper side of the transmission shaft 17 in the power transmission direction.
2 and a second support member 33 that is rotatably fitted onto the outside of the cylindrical member 28, and the cylindrical member 2
8 is provided with a transmission member 34 that can only freely slide in the axial direction,
Further, the speed change member 34 and the second support member 33 have engaging portions 34a, 33 that exhibit a speed change state other than the super deceleration state.
In addition, an engagement structure 24A is provided on the transmission member 34 and the fixed part 3 of the aircraft body to fix the movement of the transmission member 34 and create a super deceleration state, and the engagement structure 24A is connected to the transmission member 34 When engaged with the engagement structure 24A, the engaging structure 24A is configured to be able to rotate together, and normally prevents the engagement structure 24A from rotating together by the elastic pressing force, and engages against the elastic pressing force when the load exceeds a certain level. A transmission mechanism for an agricultural tractor characterized by being provided with a restrictor 24C using an elastic member 24D that allows a structure 24A to rotate together.