JPS6390435A - Running transmission structure for farm tractor - Google Patents

Abstract

PURPOSE:To aim at making a front balance weight lightweight, by attaching a front speed change gear to a front wheel transmission casing. CONSTITUTION:A front wheel output shaft 14 which is provided in a running transmission 9 so that it projects forward from a mission casing 8, is associatingly coupled with an input shaft 16 which projects rearward from a front wheel transmission casing 5, through the intermediary of a rotary shaft 15. Further, torque is transmitted from the input shaft 16 to a front wheel differential mechanism 19 through a reduction bevel gear 17 attached inside of the front wheel transmission casing 5 and a front wheel speed change gear 18.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a driving transmission which is disposed at the rear of the aircraft body, and which detects the average circumferential speed of a pair of left and right steerable front wheels and the average circumferential speed of a pair of left and right rear wheels. A front wheel transmission device that can freely switch between a standard transmission state in which the speeds are the same or almost the same, and an increased speed transmission state in which the average circumferential speed of the pair of front wheels is higher than the average circumferential speed of the pair of rear wheels. The present invention relates to a running power transmission structure for an agricultural tractor.

[Conventional technology]

The agricultural tractor mentioned above switches the front wheel transmission to an increased speed transmission state in conjunction with the steering operation of the front wheels to drive the front wheels at increased speed, so that the front wheels pull the machine and turn.
This is designed to enable turning with a smaller radius than keeping the front wheel circumferential speed the same as the rear wheel circumferential speed.

Conventionally, in this type of agricultural tractor, for example,
As shown in Japanese Patent No. 3-119530, a front wheel transmission was attached to a traveling transmission located at the rear of the fuselage.

[Problem that the invention seeks to solve]

In agricultural tractors, various types of work equipment such as rotary tillers are often connected to the rear of the machine, and when this work equipment is connected, the weight of the work equipment applied to the rear of the machine causes the load on the front wheels to be reduced when the work equipment is not connected. A balance weight may be attached to the front of the fuselage in order to prevent or suppress a reduction in the turning effect when the front wheels are driven at increased speed. When installing balance weights in this way, in the conventional case, the weight of the front wheel transmission is more on the rear wheels than on the front wheels, so the weight of the installed weights had to be increased.

An object of the present invention is to make it possible to fully utilize the small turning action of the speed-increasing front wheels while keeping the weights as light as possible, even when it is necessary to install balance weights, and to enable switching of the front wheel transmission. The aim is to make it easy to obtain a structure that is easy to operate.

[Means for solving problems]

A characteristic configuration of the present invention is that, in the driving transmission structure for an agricultural tractor, the front wheel transmission device is attached to a front wheel transmission case to which the front wheels are attached, and the front wheels are in a steering state less than a set angle. If so, the front wheel transmission is operated to the standard transmission state, and when the front wheels are steered beyond the set angle, the front wheel transmission is automatically switched to the increased speed transmission state. The operation part of the front wheel transmission is linked to the knuckle arm or tie rod of the front wheel, and its functions and effects are as follows.

[For production]

By attaching the front wheel transmission to the front wheel transmission case, the front wheel transmission can be provided with more weight being applied to the front wheels than before due to the location of the front wheel transmission case.

Due to the linkage between the knuckle arm or tie rod and the operating section, the front wheel transmission can be switched simply by operating the steering wheel to steer the front wheels.
In addition, compared to linking the knuckle arm or tie rod to the pitman arm, which is located further from the wheel transmission case, the operation section of the front wheel transmission can be easily adjusted by simply adding a smaller interlocking mechanism in terms of the interlocking distance. can be linked to the steering wheel.

〔Effect of the invention〕

Even if it becomes necessary to install a front balance weight in order to ensure sufficient front wheel ground pressure so that the front wheels can fully exert the aircraft turning action when the speed is increased, the weight of the front wheel transmission is Since more weight is placed on the front wheel than before, the balance weight can now be lighter than before, making it easier to attach and detach the balance weight that is required when connecting and separating work equipment. .

Furthermore, since switching of the front wheel transmission can be done all at once by steering the front wheels, it is possible to easily change the front wheel transmission by simply controlling the direction of the aircraft, but this requires an additional interlocking mechanism. Since the structure can be made relatively small, the structure can be simplified, which is economically advantageous.

〔Example〕

As shown in FIG. 5, a pair of left and right front wheels (1a).

(1b) so that it can be steered and driven, and a pair of left and right non-steering type rear wheels (2a) and (2b) that can be driven. Lift arm (
3), and a power take-off shaft (4
) to form an agricultural tractor.

The pair of front wheels (1a), (1b) are connected to the fuselage frame (1a), (1b) via front wheel transmission cases (5) which are separately attached to both ends.
6) is installed. And the front wheel transmission case (
5) is the longitudinal axis of the aircraft (P,
) is connected to the fuselage frame (6) so that it can swing around the pair of front wheels (
1a) and (1b) are configured to move up and down against the aircraft body in order to swing the front wheel transmission case (5) relative to the aircraft body, and maintain the aircraft horizontally or in a posture close to this when viewed in the longitudinal direction. It is. As shown in FIG. 1, the front wheel transmission case (5) has a fuselage side case part (5a) and a fuselage vertical axis (p) at both ends of the fuselage side case part (5a).
It consists of a pair of wheel-side case parts (5b), (5b) connected to swing around the wheel-side case part (5b), which is connected to the shaft center (5b) by a knuckle arm (7). P2) is operated to swing around the front wheel (1a
) and (1b) are configured to be steered.

Front wheels (1a), (1b) and rear wheels (2a),
(2b), a driving transmission (9) is installed inside the transmission case (8) which forms the rear part of the fuselage, and the output of the engine (10) is transferred to the clutch (11) and the rotating shaft (2b). 12) configured to transmit the information to the driving transmission (9) via the
Then, the rotational output of the driving transmission (9) is transmitted to the transmission case (8) through the internal rear wheel differential mechanism (
13), and is provided with a front wheel output shaft (14) that protrudes forward from the transmission case (8) to the driving transmission (9) via a rotating shaft (15). Interlockingly connected to the rearwardly projecting input shaft (16) of the front wheel transmission case (5),
As shown in Fig. 1, the rotational force of the J-axis (16) is transmitted to the front wheels via a reduction bevel gear (17) and a front wheel transmission (18) installed inside the front wheel transmission case (5). The signal is configured to be transmitted to the differential mechanism (19).

The front wheel transmission (18) is constructed as shown in FIG.

That is, a standard transmission gear (21) is rotatably attached to the input cylinder shaft (20) linked to the reduction bevel gear (17), and the first gear (22) is connected to the standard transmission gear (21).
), the speed-increasing gear (25) interlocked with the speed-increasing gear via the gear support shaft (23) and the second gear (24) is connected to the differential gear case (19a) of the front wheel differential mechanism (19).
It is attached to the output cylinder shaft (26) which is connected to the output cylinder shaft (26) so as to be relatively rotatable, and is attached to the output cylinder shaft (26) through the cylinder body (27a) so as to rotate integrally and to slide. A dog clutch (28) is provided between the transmission member (27) and the standard transmission gear (21), and the output cylinder shaft (
A multi-disc friction clutch (29) is provided between the speed-increasing interlocking gear (26) and the speed-increasing interlocking gear (25). Then, the transmission member (
27) is the sliding shifter (30) and spring (43)
The clutches (28) and (29) are constructed so as to be turned on and off as they are slidably operated by a bush rod-type operating portion (31) as shown in FIG. The transmission member (
27) and the operating section (31) are urged by a spring (32).

To explain in more detail, the operation section (31) is located at the first operation position (S
), the friction clutch (29) is disengaged, the dog clutch (28) is engaged, and the standard transmission gear (21) is operated.
) is transmitted to the output cylinder shaft (26) via the transmission member (27).
), and the front wheel differential mechanism (
13), and when the operation part (31) is operated to the second operation position (old), the dog clutch (28) is disengaged and the friction clutch (29) is engaged. The rotational force of the speed-increasing transmission gear (25) is transferred to the output sleeve (26).
) to the left and right front wheels (1a).

The average circumferential speed of (1b) is the left and right rear wheels (2a), <2b
) so that the front wheel differential mechanism (1
9) is set to an increased speed transmission state.

Then, the power is restored to the standard transmission state.

As shown in FIGS. 2 and 3, the operating portion (31) is connected to a rotating cam (44), a cam support shaft (45),
The swing arm (46) and the push/pull rod (45) are integrally rotatably attached to the protrusion from the fuselage side case part (5a).
7), and is interlocked with the knuckle arm (7) via a swing arm (48) attached to one knuckle arm (7) so as to be able to swing integrally therewith. And the position for going straight (N)
When the front wheels (1a) and (1b) are in a steering state in which the leftward and rightward steering angles are smaller than the set angle (A), the rotating cam (44) rotates as shown in FIG. 1 cam portion (44a) faces the roller (31a) of the operating portion (31) to allow the operating portion (31) to be operated to the first operating position (S) by the spring (43). and the front wheels (1a
), (1b) is steered, the rotating cam (
44) is the second cam part (44b) or the third cam part (44
c) to operate the operating section (31) to the second operating section (11). In other words, the front wheel (1a)
, (1b) is in a steering state less than the set angle (A), the front wheel transmission (18) is in the standard transmission state,
When the front wheels (1a), (1b) are steered beyond the set angle (A), the front wheel transmission (18) is configured to automatically switch to the speed increasing transmission state, 1a)
, (1b), the front wheel transmission (18
) can be switched.

Note that the shifter (49) shown in FIG.
44) is slid on the cam support shaft (45) between a lowering action position and a raising non-action position relative to the roller (31a), and the operation part (31) and knuckle arm (7) are brought into an interlocking state and a non-interlocking state. This is for switching between.

[Another example]

FIG. 6 shows another embodiment of the front wheel transmission (18), in which the rotational force from the driving transmission (9) is applied to the front wheel transmission case (5) at the same rotational speed or by increasing the speed.
) and located outside the front wheel transmission case (5) and attached to the fuselage side case portion (5a) of the front wheel transmission case (5). It is. A planetary gear speed increasing transmission mechanism (36) is provided between the input shaft (34) and the output cylinder shaft (35), and a planetary gear support member (37) of this speed increasing transmission mechanism (36) is provided.
A clutch member (3) is attached to the cylindrical portion (37a) of the input shaft (34) so as to integrally rotate and slide by spline engagement, and is provided with a rotating body (39) on the input shaft (34). When the input shaft (34) and the planetary gear support member (37) are engaged with the provided claw portion (40), the input shaft (34) and the planetary gear support member (37) are interlocked and connected so that they rotate together, and the rotational force of the input shaft (34) is transferred directly to the planetary gear support member (37). When the standard transmission state is established so that rotational speed is transmitted to the output cylinder shaft (35), and the clutch member (38) is engaged with the stopper (42) fixed to the transmission case (41), the planetary gear The support member (37) is fixed so as not to rotate, and is in an increased speed transmission state so that the rotational force of the input shaft (34) is increased in speed and transmitted to the output cylinder shaft (35).

Then, as shown in FIG. 7, the clutch member (38)
A swing-type operating section (50), which is disposed outside the transmission case (41), is interlocked with a swing shifter (not shown) via a swing shifter (not shown). Cam (52
), a pair of left and right knuckle arms (7), (
7) is interlocked with a tie rod (53). That is, the front wheel (1a).

(1b) is in a steering state below the set angle (A), even though the tie rod (53) operates the cam operating portion (53a) to press the swinging cam (52), the swinging cam (52) does not move. The first cam part (52a) of the cam (52) is the sliding rod (51)
The operation part (50) is in the standard transmission position (S) due to self-restoring force, and the front wheel (1a)
, (1b) is steered beyond the set angle (A), the swing cam (52) is operated by the tie rod (53) to swing the swing cam (52) beyond the set angle. The second cam part (52b) or the third cam part (52c) is configured to press the sliding rod (51) to operate the operating part (50) to the speed-increasing transmission position (I). .

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the transmission structure for running an agricultural tractor according to the present invention, in which FIG. 1 is a partially expanded cross-sectional view of the front wheel transmission case, and FIG. 2 is a plan view of the interlocking part between the front wheel transmission and the knuckle arm. , Figure 3 is a sectional view of the front wheel transmission operating section, Figure 4 is
The figure is a plan view of the rotary cam, Figure 5 is a partially cutaway side view of the entire agricultural tractor, Figure 6 is a sectional view of a front wheel transmission implemented separately, and Figure 7 is a plan view of the operating section of the front wheel transmission. be. (1a), (1b) ...-front wheel, (2a)
, (2b) ... Rear wheel, (5) ...
・Transmission case for front wheels, (7)...Knuck lure 4, (9)...Transmission for driving, (
18)...Front wheel transmission, (31), (5
0)......Operation unit, (53)...Tie rod, (A)...Setting angle.

Claims (1)

[Claims] The driving transmission (9) is located at the rear of the aircraft, and the average circumferential speed of the pair of left and right steerable front wheels (1a), (1b) and the average circumferential speed of the pair of left and right rear wheels (2a), (2b) are determined. and a standard transmission condition that makes them the same or nearly the same,
A front wheel transmission ( 1
8), wherein the front wheel transmission (18) is connected to the front wheels (1a), (
1b) attached to the front wheel transmission case (5),
When the front wheels (1a), (1b) are in a steering state less than the set angle (A), the front wheel transmission (18) is operated to the standard transmission state, and the front wheels (1a), (1b) are operated to the standard transmission state. 1b
) is steered beyond the set angle (A), the front wheel transmission (18) is automatically switched to the speed-increasing transmission state.
or 50) is interlocked with the knuckle arm (7) or tie rod (53) of the front wheels (1a), (1b).