JPH0334343Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention provides a transmission system for the steerable front wheels with a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and a rear wheel drive speed The front wheel transmission is equipped with a front wheel transmission that switches to an accelerating drive state in which transmission is performed at a higher drive speed, and the front wheel transmission is operated as standard in conjunction with depression of either the left or right handbrake pedal, which independently brakes the left and right rear wheels. The present invention relates to a front wheel speed change operation structure for an agricultural tractor configured to switch from a drive state to an increased speed drive state.

[Conventional technology]

If you want to turn with a small turning radius in a narrow field, etc. while working in the field with standard drive, stop one side of the rear wheels and drive only one side, and set the front wheels to speed-up drive to quickly turn with a small turning radius. In this case, the means to link the depression of the left and right handbrake pedals of the rear wheels with the front wheel transmission is to detect the depression by a limit switch or the like, and use a logic circuit to determine whether the left or right handbrake pedal is Some systems are configured to send an operation command to the actuator that operates the control lever of the front wheel transmission only when either side of the handbrake pedal is depressed, but with this type of electrical linkage, the following Had a problem.

[Problem that the invention attempts to solve]

In other words, with this structure, an electrical line would be installed near the left and right handbrake pedals, but this is located at the bottom of the machine and is equipped with a limit switch to break through mud and water while driving in the field. This caused a decline in the reliability and durability of the electrical system. Furthermore, in order to improve the reliability and durability of the electrical circuit, it may be considered to subject the electrical circuit to mud and water shielding treatment, but this would only unnecessarily increase manufacturing costs.

An object of the present invention is to construct an interlocking mechanism between the left and right side brake pedals for braking the rear wheels and the front wheel transmission into a mechanism that has high reliability and durability while minimizing costs.

[Means for solving problems]

The feature of the present invention is that in the above-mentioned front wheel shift operation structure of an agricultural tractor, wire support arms are connected to the left and right handbrake pedals, and one wire support arm is connected to the inner wire of the first release wire and the second release wire. The outer wire of the first release wire and the inner wire of the second release wire are connected and supported by the other wire support arm, and the other end of each inner wire of the first and second release wires is connected and supported. is linked to the operating lever of the front wheel transmission, and by depressing either the left or right handbrake pedal, only one of the first and second release wires is pulled, and the operating lever operates to increase speed transmission. The operation and effects are as follows.

[Effect]

With the above-described structure, when only one of the left and right handbrake pedals is depressed, one of the inner wires of the first and second release wires is pulled and operated in conjunction with this. Since the outer wire of the inner wire that has been pulled is attached to the side of the handbrake that has not been pressed, the inner wire is pulled with respect to the outer wire at the other end of the released release wire that has been operated, and this inner wire The operating lever of the front wheel transmission linked to is switched to the front wheel speed increasing state. On the other hand, if both the left and right hand brake pedals are depressed simultaneously, both the outer wire and the inner wire of the first and second release wires are linked to the left and right hand brake pedals, so both inner wires at the other ends of both release wires are connected to both outer wires. The wire is not pulled in, and the front wheel transmission control lever is not switched.

[Effect of idea]

As explained above, the interlocking mechanism between the left and right handbrake pedals and the front wheel transmission uses a mechanical release wire, which has higher reliability and durability against mud and water than electrical structures. By doing so, it was possible to improve the reliability and durability of the interlocking mechanism while suppressing costs as much as possible.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An agricultural tractor that is an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a fuselage frame 3 that supports a pair of left and right steering type front wheels 1, 1 and rear wheels 2, 2 in a freely drivable manner includes an engine 4, a main clutch 5, a transmission case 6, and a control section. 7, and a lift arm 8 that can be driven up and down to freely swing up and down to connect various working devices such as a rotary tiller to the rear of the machine, and a PTO that transmits power to the working devices.
A four-wheel drive agricultural tractor is constructed by providing a shaft 9.

Next, to explain the power transmission system of the agricultural tractor in detail, as shown in FIG. The power is transmitted to a device (not shown), which performs a gear change operation to drive the rear wheels 2, 2, and the power branched from the sub-transmission device is sent to the front wheel differential mechanism 1a via the front wheel transmission device 10 and the front wheel output shaft 15. and drives the front wheels 1,1.

The front wheel transmission 10 has a standard drive state A in which the power branched from the auxiliary transmission is driven at a speed substantially equal to the front and rear wheel drive speed, and a standard drive state A in which the front wheels are driven at a speed faster than the rear wheel drive speed. Speed-up drive state B
It is configured to perform a gear change operation and transmit the information to the front wheels 1, 1.

Next, the linkage structure between the left and right side brake pedals 12a, 12b, which brake the rear wheels 2, 2 independently on the left and right sides, and the front wheel transmission 10 will be described in detail.As shown in FIG. The handbrake pedals 12a, 12b are supported downward in parallel so that they can be depressed and operated independently, and wire support arms 13a, 13 are attached to the swinging boss portions of the left and right handbrake pedals 12a, 12b, respectively.
b, and connect the first release wire 1 to the wire support arm 13a of the left side brake pedal 12a.
While attaching the inner wire 14a of No. 4 and the outer wire 16b of the second release wire 16,
An outer wire 14b of the first release wire 14 and an inner wire 16a of the second release wire 16 are attached to the wire support arm 13b of the right side brake pedal 12b.

The other ends of the first and second release wires 14 and 16 are linked to the front wheel transmission 10, and the details thereof are as follows.
The outer wires 14b and 16b are fixed to the outer wall of the front wheel transmission 10, and the inner wire 1
4a and 16a are in the standard drive state A by the spring 17.
It is connected to an operating lever 10a for shifting gears which is biased toward the side.

[Brief explanation of the drawing]

The drawings show an embodiment of the front wheel speed change operation structure for an agricultural tractor according to the present invention, and FIG.
FIG. 2 is an overall side view of the agricultural tractor. 1...Front wheel, 2...Rear wheel, 10...Front wheel transmission, 10a...Operation lever, 12a, 12b...
Left and right side brake pedals, 13a, 13b...
...Wire support arm, 14...First release wire, 14a...Inner wire of first release wire, 14b...Outer wire of first release wire, 16...Second release wire, 16a...
...Inner wire of second release wire, 16b
...Outer wire of the second release wire.

Claims (1)

[Scope of utility model registration request] In the transmission system to the steerable front wheels 1, 1, the rear wheels 2,
2, and a front wheel transmission 10 that switches between a standard drive state in which transmission is performed at a drive speed substantially equal to the drive speed of the rear wheels 2, and an increased speed drive state in which transmission is performed at a drive speed greater than the drive speed of the rear wheels 2, 2. Left and right side brake pedals 12a, 1 that brake 2 independently on the left and right sides
2b, the front wheel transmission device 10 is configured to switch from a standard drive state to an increased speed drive state in response to a depression operation of either one of the left and right hand brake pedals 12a, 12b. Wire support arms 13a and 13b are connected from each other, and one wire support arm 13a connects and supports the inner wire 14a of the first release wire 14 and the outer wire 16b of the second release wire 16, and the other wire support arm 13b connects and supports the outer wire 14b of the first release wire 14 and the inner wire 16a of the second release wire 16, and connects the other end of each inner wire 14a, 16a of the first and second release wires 14, 16 to the front wheel. In conjunction with the operating lever 10a of the transmission 10, only one of the first and second release wires 14, 16 is pulled by depressing either the left or right side brake pedals 12a, 12b, and the operating lever is 10a is a front wheel speed change operation structure for an agricultural tractor configured to be switched to an increased speed transmission state.