JPH062038Y2 - Travel speed change structure of agricultural tractor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is a traveling speed change of an agricultural tractor incorporating a hydraulic clutch type speed change mechanism capable of direct switching operation without requiring the operation of turning on and off the main clutch. Regarding the structure.

[Conventional technology]

In this type of agricultural tractor traveling speed change structure, as the hydraulic clutch type speed change mechanism, only one of the auxiliary speed change mechanism and the forward / reverse switching mechanism is equipped (for example, Japanese Patent Laid-Open Publication No. Sho.
61-252922).

[Problems to be solved by the invention]

Therefore, if one of the sub-transmission mechanism and the forward / reverse switching mechanism is of the hydraulic clutch type, the other is of the gear type, so that both are inferior in operability to the hydraulic clutch type. Especially in the case of operations such as snow shoveling, in which the forward and backward movements are repeated frequently and the traveling speed is switched between forward and reverse traveling, it is necessary to adopt a speed change mechanism that can further improve operability. Was there.

It is an object of the present invention to provide an arrangement capable of efficiently arranging a speed change structure and simplifying a hydraulic piping structure associated therewith in order to improve drivability.

[Means for solving problems]

The characteristic configuration according to the present invention is that a sub-transmission mechanism of a hydraulic clutch type and a forward / reverse switching mechanism of a hydraulic clutch type are arranged in front of and behind the main gear transmission mechanism, and that a hydraulic clutch mounted at a rear portion of the main gear transmission mechanism is mounted. The point where the front end of the shaft and the rear end of the transmission shaft in the main gear speed change mechanism are relatively rotatably fitted and connected, and the oil passage to the rear hydraulic clutch of the main gear speed change mechanism is provided between the mounting shaft and the transmission shaft. And a point that a rotary joint mechanism for connecting an oil passage is provided at the front end of the transmission shaft, and the operation and effect thereof are as follows.

[Action]

By changing the sub-transmission mechanism and the forward / reverse switching mechanism to those of the hydraulic clutch type from the configuration, it is possible to directly change both mechanisms without operating the seed clutch. However, since the speed change mechanism with such a hydraulic clutch has a large structure from the beginning, it is advantageous to position it on the input side where the shaft torque is small because the structure can be made as small as possible. Therefore, it is inevitable that both hydraulic clutch type transmissions are arranged in the front and rear and the main gear transmission is located in the rear part, and the installation position of the main gear mechanism is displaced rearward from the transmission structure in the above-mentioned prior art publication. To do. However, assuming that two hydraulic clutch type speed change mechanisms are incorporated into the existing mission structure, by disposing both hydraulic clutch type mechanisms before and after the main gear speed change mechanism as in the present invention, the main gear speed change mechanism is arranged. Since there is no need to change the position of the mechanism,
It is possible to reduce changes in the installation position of the operation lever and the linkage mechanism between the operation lever and the main gear speed change mechanism, which are provided on the driver side. Moreover, in the conventional speed change structure, since the gear type auxiliary speed change mechanism can be incorporated in the main gear speed change mechanism, either one of the hydraulic clutch mechanisms can be put in the empty space, and a hydraulic clutch is realized. However, there is no need to change the layout significantly.

However, in order to configure the hydraulic pressure supply structure for this hydraulic clutch by arranging one hydraulic clutch type speed change mechanism at the rear part of the main gear speed change mechanism, this hydraulic clutch includes the main gear speed change mechanism and the rear wheel differential mechanism ( Since it is sandwiched by the super-reduction mechanism in the above publication), it is positioned in the middle of the transmission case, and if a rotary joint mechanism for supplying hydraulic pressure is arranged before and after the hydraulic clutch, the adjacent main gears The transmission mechanism and the super-reduction mechanism must be provided separately from this hydraulic clutch, and the front-rear length of the transmission case becomes longer accordingly. In the case of the present invention, however, the oil is not placed in the transmission shaft of the main gear transmission mechanism. By providing a path and supplying oil from the front end of this transmission shaft, the installation position of the rotary joint mechanism can be located at the front end of the mission case. The empty space below the main clutch is available.

[Effect of device]

The operation (a) facilitates the operation, and is particularly effectively used in the case where the traveling speed is different in the forward / rearward traveling state. Further, from the action B, it is possible to reduce the modification of the structure of the mission when hydraulicizing the existing mission structure, and it is advantageous in terms of remodeling cost.

〔Example〕

As shown in FIG. 3, the agricultural tractor has front and rear wheels (1),
The vehicle (3) supported by (2), the vehicle (3), the main clutch (5) on the rear surface of the engine (4) via the housing, the mission case (6), the rear of the mission case (6). PTO shaft (7) arranged at the end, driver's seat arranged in the center of the vehicle
(8), and is comprised.

As shown in FIG. 2, in the mission case (6), the output from the engine (4) is concentrically arranged on the PTO transmission shaft.
(9) and transmitted to the PTO shaft (7) and the front and rear wheels (1), (2) via the traveling first transmission shaft (11) fitted onto the PTO transmission shaft (9), respectively. The transmission system is configured as described above. That is, the PTO transmission shaft (9) is separated into front and rear via the hydraulic clutch (12), and the power transmitted to the front PTO transmission shaft (9A) is the rear PTO transmission shaft (9B) and the reduction gear. It is transmitted to the PTO shaft (7) via the mechanism (13). On the other hand, the power transmitted from the first drive shaft for traveling (11) is a hydraulic clutch planetary gear type auxiliary transmission mechanism (14) (known as a dual transmission mechanism, in which the low speed is reduced by about 25% relative to the high speed, Used when a person senses insufficient torque)
It reaches the rear wheel differential mechanism (18) via a main gear transmission mechanism (15) capable of shifting in four stages, a hydraulic clutch type forward / reverse switching mechanism (16), and a super speed reduction mechanism (17). Also, rear wheel differential mechanism (18)
Power to the front wheel transmission shaft (20) via the reduction gear mechanism (19)
To the front wheel (1).

The main gear speed change mechanism (15) is provided with four pairs of gear mechanisms extending over the traveling first transmission shaft (11) and the traveling second transmission shaft (10) installed in parallel with the second transmission shaft (11). The clutch sleeves (21), (21) provided on the (10) side shift the gear in four stages.

Next, the forward / reverse switching mechanism (16) will be described in detail. As shown in FIG. 1, a third traveling drive shaft (22) as a hydraulic clutch mounting shaft concentric with the second traveling drive shaft (10) is provided behind the second traveling drive shaft (10). And the second for traveling
The front end of the traveling third transmission shaft (22) is fitted into the rear end of the transmission shaft (10) so as to be relatively rotatable. The hydraulic clutch case (23) is keyed and fixed to the traveling third transmission shaft (22), and the reverse drive input gear (24) is positioned behind the hydraulic clutch case (23). Axis (2
It is loosely fitted in 2). On the other hand, an output gear (26) is located in front of the hydraulic clutch case (23), and the output gear (26) is formed integrally with the rear end of the second traveling transmission shaft (10). And before and after the partition wall (23A) of the hydraulic clutch case (23),
Wet friction multi-plate clutch (25
A) and (25B) are provided, and when the front friction multi-plate clutch (25A) operates, the hydraulic clutch case (23) and the output gear (26) are integrated, and when the rear friction multi-plate clutch (25B) operates. The hydraulic clutch case (23) and the reverse drive input gear (24) are integrated.

A fourth traveling power transmission shaft (27) is arranged concentrically behind the traveling first transmission shaft (11), and the traveling fourth transmission shaft (27) is arranged.
A large diameter input gear (29) is integrally formed on the
(30) is fitted with a spline. Large diameter input gear (29)
Is always in mesh with the output gear (26) of the second transmission shaft (10) for traveling, and the small diameter output gear (30) is the input gear of the third transmission shaft (22) for traveling through the idle gear (31). It is linked to (24). Therefore, when the front friction multi-plate clutch (25A) is activated, the traveling second transmission shaft (10) and the traveling third transmission shaft (2
2) and are integrated and the forward state appears. On the contrary, when the rear friction multi-plate clutch (25B) is activated, the output from the second drive shaft for traveling (10) is transferred to the third drive shaft for traveling via the fourth drive shaft for traveling (27). It is transmitted to (22) and the reverse state appears.

The hydraulic pressure supply structure for the front and rear friction multi-plate clutches (25A, 25B) will be described below. As shown in FIG. 1, the friction plate is configured so as to be pressed and urged by a piston (33) urged by a spring (32) in a separating direction, and a hydraulic oil is provided on the rear side of the piston (33). An outlet is provided for this piston
(33) is pushed and moved against the urging force in the direction of pressing the friction plate. The oil passage (a) to the front friction multi-plate clutch (25A) is bored at the axial center positions of the traveling second transmission shaft (10) and the traveling third transmission shaft (22), and the traveling second transmission shaft is formed. It communicates with an oil passage connecting rotary joint mechanism (34) provided at the front end of (10). On the other hand, the oil passage (b) to the rear friction multi-plate clutch (25B) is located at a position eccentric from the shaft center of the second and third transmission shafts (10) and (22) and
A rotary joint mechanism for oil passage connection drilled in parallel with (a)
It communicates with (34). In this oil passage (b), since the traveling second transmission shaft (10) and the traveling third transmission shaft (22) rotate relative to each other,
The rotary joint mechanism (35) is required at the connection with the second and third transmission shafts (10), (22). This revolving joint mechanism (35)
Is the rear end surface of the second traveling transmission shaft (10) and the front end surface of the third traveling shaft between the traveling second transmission shaft side outlet and the traveling third transmission shaft side inlet of the oil passage (b). Oil sump space surrounded by
It is formed by providing (c). On the other hand, the rotary joint mechanism (34) for oil passage connection has the second drive shaft (10) for traveling.
Supply ports (d) and (d) that are loosely fitted to the front end of the shaft in a state that allows relative rotation and communicate with the oil passages (a) and (b) from the two outer peripheral surfaces of the transmission shaft (10).
Is provided.

[Another embodiment]

The sub-transmission mechanism (14) and the forward / reverse switching mechanism (16) may be installed at different positions.

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 shows an embodiment of a traveling speed change structure of an agricultural tractor according to the present invention, and FIG. 1 is a longitudinal sectional view showing the structure of a forward / backward movement mechanism,
FIG. 2 is a schematic configuration diagram showing a mission case structure, and FIG.
FIG. 1 is a side view of an agricultural tractor. (10) …… Transmission shaft, (14) …… Sub transmission mechanism, (15) …… Main gear transmission mechanism, (16) …… Forward / reverse switching mechanism, (22) …… Hydraulic clutch mounting shaft, (25) ...... Rear hydraulic clutch, (34) …… Revolving joint for oil passage connection.

Claims (1)

[Scope of utility model registration request] 1. A hydraulic clutch type auxiliary transmission mechanism (14) and a hydraulic clutch type forward / reverse switching mechanism before and after the main gear transmission mechanism (15).
(16) and the front end of the hydraulic clutch mounting shaft (22) located at the rear of the main gear speed change mechanism (15) and the rear end of the transmission shaft (10) of the main gear speed change mechanism (15) are opposed to each other. The main gear speed change mechanism (15) has a rear hydraulic clutch (2
The oil passages (a) and (b) to 5) are provided in the shaft of the mounting shaft (22) and the transmission shaft (10), and the oil passage connection rotation is provided at the front end of the transmission shaft (10). A traveling speed change structure for an agricultural tractor provided with a joint mechanism (34).