JPS6152014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hydraulic continuously variable transmission and a speed detection device for detecting the output rotational speed of each of the front wheels and rear wheels, respectively. The operating member of one of the transmissions is configured to be linked to a travel shift lever to perform a gear shift operation, and
A speed detection device that is provided with a drive mechanism that performs a speed change operation on an operating member of the other transmission, and that a detected value by the speed detection device that detects the output rotational speed of the other transmission detects the output rotational speed of the one transmission. Relating to a traveling transmission device for a tractor configured to automatically operate the drive mechanism so as to have a preset relationship with respect to a detected value,
Sudden shift of one gear by traveling gear lever,
Further, it is an object of the present invention to enable the other transmission to quickly and efficiently shift gears in response to a wide range of gear shifts.

In the above-mentioned traveling transmission, the traveling speed can be changed steplessly using hydraulic continuously variable transmissions provided for each of the front and rear wheels, and one of the transmissions can be operated directly using the traveling gear lever. The rotation of the front and rear wheels is controlled by using a drive mechanism to shift the other transmission so that it has a preset relationship based on the detected output rotational speed of the other transmission. Although it is possible to always maintain the speed in an appropriate relationship throughout the entire shifting range, it has the following problem.

In other words, although the time required to shift the other transmission by a unit amount using the drive mechanism is small, it is longer than the time required to rapidly shift one transmission by a unit amount using the shift lever. When one transmission is suddenly operated over a large range with the gear shift lever, the output rotational speed of one transmission and the output rotational speed of the other, in other words, the rotational speed of the front and rear wheels temporarily change to an appropriate level. There was a risk that the wheels would come out of alignment, causing problems such as the front and rear wheels slipping unnecessarily and causing premature wear.

The present invention has been made with the above-mentioned problems in mind, and provides a traveling transmission for a tractor having the above-mentioned structure, in which the drive mechanism and the operation member of the other transmission operated by the drive mechanism are frictionally operated. The speed change lever and the operating member of the other transmission are interlocked via a transmission mechanism so as to be able to change gears, and the shift lever and the operating member of the other transmission are interlocked via a linkage mechanism that has the flexibility to release the link within a certain small range. It is characterized by

In other words, even when you want to change the speeds of the transmissions corresponding to the front and rear wheels rapidly and over a large range,
Conventionally, one transmission device could suddenly change gears over a large range by directly operating the gear lever;
Since the entire shift operation amount for the other transmission device is operated by the drive mechanism, it takes time, and there is a risk that the rotational speeds of the front and rear wheels may temporarily deviate significantly from the appropriate relationship. According to the invention, since the gear shift lever and the operating member of the other transmission are interlocked via a linkage mechanism that has the flexibility to release the link within a certain small range, sudden changes that exceed this certain small range are possible. When operating the gear shift lever,
The other transmission is operated in conjunction with the other transmission, and the gear can be shifted to a value close to the preset relationship even though it is out of the preset relationship, so the time required for subsequent gear shifting by the drive mechanism is reduced, and the gear can be quickly shifted to the desired relationship. can.

Moreover, since the drive mechanism and the operating member of the other transmission are linked via a friction transmission mechanism, the drive mechanism is not forced to be forced to be driven even though the other transmission is operated by the gear shift lever. This prevents breakdowns caused by forced drive of the drive mechanism. Since the amount of shift operation by the drive mechanism is relatively small, the shift operation of the other transmission by the drive mechanism is performed within a certain small range of flexibility in which the link between the shift lever and the operating member of the other transmission is released. Nevertheless, the gearshift lever does not move and one of the transmissions is not operated by this drive mechanism. Also,
To obtain a traveling transmission for a tractor which can be used more conveniently by preventing the output rotational speeds of both transmissions from greatly deviating from a desired setting relationship during sudden gear changes.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 illustrates a side view of a four-wheel drive agricultural tractor, where 1, 1 is the front wheel whose direction is changed;
3 is a rear wheel, 3 is an engine provided at the front of the aircraft, 4 is a clutch housing directly connected to the engine 3,
5a and 5b are hydraulic pumps that are interlocked with the engine 3 via a transmission clutch (not shown) in the clutch housing 4; 6 is a rear rear wheel transmission case in which a differential transmission mechanism and the like are installed; 7 is an attachment. PTO used to drive work equipment
8 is a lift arm used to raise and lower the attachment working device; 9 is a driver's seat; and 10 is a steering handle.

Next, the traveling transmission will be explained.

That is, the hydraulic pumps 5a and 5b are configured as variable displacement types, and one pump 5a is configured to supply pressure oil to the front wheel drive motor 11, and the other pump 5b is configured to supply pressure oil to the rear wheel drive motor 12. One pump 5a and the front wheel drive motor 11 constitute a hydraulic continuously variable transmission for the front wheels 1, 1, and the other pump 5b and the rear wheel drive motor 12 From rear wheel 2,
A hydraulic continuously variable transmission for No. 2 is constructed.

As shown in FIG. 2, a speed change lever 14 is fixed to a rotary operation shaft 13 for adjusting the discharge amount of a hydraulic pump 5a as an operation member in the continuously variable transmission device corresponding to the front wheels 1, 1. 14
The front wheel continuously variable transmission is configured to change gears by the rocking motion of the front wheel. The speed change lever 14 is configured to be held at a desired position by a friction mechanism (not shown) installed between the case of the hydraulic pump 5a and the base of the lever.

As shown in FIG. 3, a multi-plate friction transmission mechanism 16 is connected to a rotary operating shaft 15 for adjusting the discharge amount of the hydraulic pump 5b as an operating member in the continuously variable transmission device corresponding to the rear wheels 2, 2. The first operating arm 17 is supported relatively rotatably, and the second operating arm 18 is supported relatively non-rotatably. The first operating arm 17 is interlocked and connected via a rod 21 to a swinging arm 20 that is swing-operated by an electric motor 19 serving as a drive mechanism, and the electric motor 19 is connected to an axle 1a that supports the front wheel 1. A second speed detection unit detects the output rotational speed of the rear wheel drive motor 12 based on the detection result of the first speed detection device 22 which detects the rotational speed of the front wheels 1, 1 as the output rotational speed of the continuously variable transmission of the front wheels 1, 1. The device 23 is configured to automatically rotate forward and backward so that the detected value has a preset relationship with the detected value of the first speed detecting device 22. The device is configured to be operated to change speed using an electric motor 19 so as to have a preset relationship with the output rotational speed of the continuously variable transmission for the front wheels.

Further, the second operating arm 18 is connected to the first rod 2.
4a and the second rod 24b are interlocked and connected to the lever 14 via a telescopic rod 24, which serves as a linkage mechanism in which the lever 4a and the second rod 24b are telescopically engaged and connected only within a certain small range. When the gear shift lever 14 is suddenly operated over a large range, the gear is directly operated by the lever 14, and then when the gear is operated by the motor 19 in a manner that is corrected to a desired value, The lever 14
and the second operating arm 18 are disengaged from each other.

[Brief explanation of the drawing]

The drawings show an embodiment of the traveling transmission device for a tractor according to the present invention, in which FIG. 1 is a side view of the agricultural tractor, FIG. 2 is a diagram of the connection between the speed change lever and the hydraulic pump, and FIG. FIG. DESCRIPTION OF SYMBOLS 1... Front wheel, 2... Rear wheel, 13, 15... Operation member, 22, 23... Speed detection device, 14... Gear shift lever, 16... Friction transmission mechanism, 19... Drive mechanism, 24... Coordination mechanism.

Claims (1)

[Claims] 1 Separate hydraulic continuously variable transmissions and speed detection devices 22 and 23 for detecting the output rotational speed thereof are provided corresponding to each of the front wheels 1 and the rear wheels 2, and one of the transmissions is The operating member 13 is configured to be linked to the traveling speed change lever 14 to perform a speed change operation, and a drive mechanism 19 is provided to perform a speed change operation on the operation member 15 of the other transmission, and the output rotational speed of the other transmission is detected. Speed detection device 2
The driving mechanism 19 is configured to automatically operate so that the detected value by the speed detecting device 22 that detects the output rotational speed of the one transmission device has a preset relationship with the detected value by the speed detecting device 22 that detects the output rotational speed of the one transmission device. This is a traveling transmission for a tractor, in which the drive mechanism 19 and an operating member 15 of the other transmission operated by the drive mechanism 19 are linked to enable gear changes via a friction transmission mechanism 16, and the gear shift lever 1
4 and the operating member 15 of the other transmission device, the linkage mechanism 2 has the flexibility to release the linkage within a certain small range.
1. A traveling transmission for a tractor, characterized in that the transmission is interlocked and connected via a transmission gear.