JPH04271930A - Brake device for tractor - Google Patents

Abstract

PURPOSE:To prevent the floating-up of the rear part of a car body and reduce the brake capacity of a rear wheel brake by operating the rear wheel brake, together with a front wheel brake, in the selection to the two-wheel drive traveling state in which traveling is performed by the drive of only front wheels, in a four-wheel drive traveling type tractor for steering rear wheels. CONSTITUTION:In interlocking with the selection between the four and two wheel drive travelings, a rear wheel brake 3 can be operated by switching to the two-wheel drive traveling, and the rear wheel brake 3 can not be operated by switching to the four-wheel drive traveling.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a brake device for a tractor.

0002

[Prior Art and Problems to be Solved by the Invention] In a tractor that uses four-wheel drive with the rear wheels as steering wheels, when traveling on the road or when working with a mower, the rear wheels are not driven and two wheels are driven. When driving on steep slopes, the rear wheels are often driven, resulting in front and rear four-wheel drive. When driving in two-wheel drive, if only the front wheels are braked when moving forward, it is easy to fall forward, and the rear wheels use small-capacity brakes, so they are constantly used in four-wheel drive. If you leave it in a condition where it can, it will easily cause wear and damage.

[0003] The present invention eliminates these deficiencies.

0004

[Means for Solving the Problems] This invention provides four-wheel drive driving in which the front wheels 1 and steerable rear wheels 2 are driven, and two-wheel drive driving in which only the front wheels 1 are driven. For tractors that can be switched, when traveling in two-wheel drive, the rear wheel 2
The brake device is configured to switch and interlock so that the rear wheel brake 3 is applied and the rear wheel brake 3 is not applied during four-wheel drive driving.

[0005]

[Operation and Effects of the Invention] When driving on the road or mowing lawns on flat land, the driving of the rear wheels 2 is cut off and the mode is switched to two-wheel drive driving using only the front wheels 1. In this configuration, the rear wheel brake 3 of the rear wheel 2 is simultaneously in a state where it can be applied together with the front wheel brake of the front wheel 1. Therefore, if the front wheels 1 are driven to move forward and the rear wheels 2 are used for steering, and the brakes are applied while driving, the rear brake 3 of the rear wheels 2 will be applied as well as the front brake of the front wheels 1. Therefore, it is difficult for the rear wheel 2 side of the vehicle body to rise and form an unstable posture in which the vehicle body falls forward around the front wheel.

When working or traveling on sloped or soft ground, the rear wheels 2 are also driven to provide a four-wheel drive mode. As a result, only the front wheel brake of the front wheel 1 can be applied without the rear wheel brake 3 being applied. In this configuration, even if only the front wheel brakes are applied while moving forward, the rear part of the vehicle body does not float up, etc., and is stable, and the rear wheel brakes 3 are not used, so there is less wear.

[0007] In this way, the rear wheel brake 3 can be switched and applied only when necessary with a simple operation, safe driving can be maintained, and the brake capacity can be reduced.

[0008]

[Embodiment] In FIGS. 1 to 3, the tractor body includes an engine 4 and a clutch housing 5 from the rear to the front.
, the transmission case 6, the front axle transmission case 7, etc. are integrally connected, and the front wheels 1 are mounted on both left and right sides of the front axle transmission case 7, and the front axle transmission is transmitted from the transmission device in the mission case 6. Transmission is transmitted to the front axle 8 via a differential gear in the center of the case 7, and the front wheel brakes 9 are interlocked by brake pedals 11 at the front of the control floor 10 so as to brake the rotation of the left and right front axles 8. It is configured so that it can be operated. 12 is a brake arm that operates the front wheel brake 9; 13 is this brake arm 12 and the brake pedal 1;
This is a rod that connects 1 to 1.

A rear axle bracket 14 is provided at the rear end of the vehicle body.
are integrally supported, and the center part of the rear axle transmission case 15 is supported swingably around the center pivot 16 on the lower side, and a differential gear is provided in the center part of the rear axle transmission case 15. The configuration is such that the power is transmitted to the left and right rear wheels 2 via a rear axle, gears, etc. Further, power transmission to the rear wheels 2 is transmitted from the transmission device of the front axle case 7 to the rear wheel transmission shaft 18.
The differential gear in the rear axle transmission case 15 is interlocked with the center pivot 16 via the center pivot 16. The rear wheel brake 3 is provided in front of the center pivot 16 of the rear axle transmission case 15, and brakes the transmission shaft located at the center pivot 16 and interlocked with the rear wheel transmission shaft 18, thereby controlling the left and right rear wheels. This is a configuration that brakes the rotation of the wheels 2.

This rear wheel brake 3 has an outer wire 17
An arm 21 integrated with the switching lever 20 is connected to a sliding member 24 which is fitted and guided by a pin 22 and an elongated hole 23 via an inner wire 19 passing therethrough, and the tip of this sliding member 24 is engaged. The pin 25 can be switched into and out of the rotation range of the brake arm 12 by operating the switching lever 20. A switching clutch is provided in the front axle transmission case 7 to the transmission case 6 to turn on and off the transmission to the front wheel transmission shaft 18, and this switching clutch is switched by operating the switching lever 20 to transmit the transmission to the front wheel transmission shaft 18. It is possible to set the vehicle to wheel drive, and to switch off the transmission to the front wheel transmission shaft 18 to create two-wheel drive. In the two-wheel drive position 2WD of the switching lever 20, the engagement pin 25 is located within the rotation range of the brake arm 12, and the operation of the brake pedal 11 applies the front wheel brake 9 and the rear wheel brake 2 (FIG. 1). Also, switching lever 20
When the rear wheel brake 3 is operated to the four-wheel drive position 4WD, the brake arm 12 cannot engage the engagement pin 25, so the rear wheel brake 3 cannot be applied (FIG. 2).

The rear wheel brake 3 has a smaller brake drum diameter and smaller brake capacity than the front wheel brake 9. The rear wheels 2 are steerably linked by operating a steering handle 26 at the front of the vehicle body. 27 is a cockpit, and 28 is a radiator at the rear end. A mower 29 is connected to the front of the vehicle body by a lift link 30 so as to be movable up and down.

[0012] In FIGS. 4 and 5, the points different from the above example are as follows.
A sub-shift lever 32 for shifting the sub-transmission device 31 in the mission case 6 is linked to switching of the rear wheel brake 9. The sub-shift lever 32 can be rotated back and forth from the neutral position N to a low-speed position L or a high-speed position H, and at this low-speed position L or high-speed position H, it can be moved sideways to engage the operation panel 33. When engaged with the joints 34 and 35, a four-wheel drive position can be achieved. The base of the sub-transmission lever 32 interlocks a shift arm 36 that interlocks the shifter of the sub-transmission device 31, interlocks a rod 38 to engage and disengage a switching clutch gear 37 of the rear wheel transmission shaft 18, and further interlocks a rod 38 to engage and disengage a switching clutch gear 37 of the rear wheel transmission shaft 18. 11 and the brake arm 39 of the rear wheel brake 3, the wire receiving member 40 at the end of the outer wire 17 through which the inner wire 19 is inserted is configured to be rotated, and the wire receiving member 40 and the sub-shift lever 32 are connected to each other by a rod. It is connected by 41.

[0013]Thereby, the sub-shift lever 32 can be operated back and forth from the neutral position N to shift to the high-speed position H or the low-speed position L, but this shift is performed in the two-wheel drive position 2WD (FIG. 4). When switching from the two-wheel drive position 2WD to the four-wheel drive position 4WD, operate the sub-shift lever 32 laterally in the low-speed position L or high-speed position H to engage the engaging portion 34 or 35, and the changeover will occur. When the clutch gear 37 is engaged, the sub-shift is performed at the low speed position L to transmit four-wheel drive (FIG. 5), or at the high speed position H. Moreover, the two-wheel drive position 2W of the sub-shift lever 32
In D, when the outer wire 17 is pushed by the wire receiving member 40 and the inner wire 19 is pulled, and the brake pedal 11 is stepped on, the rear wheel brake 3 can be applied by pulling the inner wire 19 (FIG. 4). Furthermore, when the sub-shift lever 32 is in the four-wheel drive position 4WD, even if the outer wire 17 is loosened and the brake pedal 11 is depressed, the rear wheel brake 3 cannot be applied (FIG. 5).

42 is a spring, and 43 is a return spring. Figure 6
The difference from the above example is that the brake pedal 11 and the brake arm 12 of the rear wheel brake 3 are directly connected by an inner wire 19, and the end of the outer wire 17 is connected to the switching clutch gear between the two-wheel drive position 2WD and the four-wheel drive position. When the switching lever 20 is pivoted to the four-wheel drive position 4WD, the outer wire 17 is loosened and the inner wire 19 is loosened. , when the front wheel brake is applied with the brake pedal 11, the rear wheel brake 3 by this inner wire 19 is not applied. However, when switching to the two-wheel drive position 2WD, the outer wire 17 is pushed by the link arm 45 and the inner wire 19
is tensioned, and by depressing the brake pedal 11, the rear wheel brake 3 can also be applied.

[Brief explanation of the drawing]

The figure shows an embodiment of the invention.

FIG. 1 is a side view showing the interlocking state of brakes.

FIG. 2 is a side view showing the interlocking state of the brakes.

FIG. 3 is a side view of the tractor.

FIG. 4 is an interlocking mechanism diagram showing the interlocking state of the brake and the sub-shift lever.

FIG. 5 is an interlocking mechanism diagram showing the interlocking state of the brake and the sub-shift lever.

FIG. 6 is an interlocking mechanism diagram showing a partial example.

[Explanation of symbols]

1 Front wheel 2 Rear wheel 3 Rear wheel brake

Claims (1)

[Claims] Claim 1: A tractor capable of switching between four-wheel drive driving in which the front wheels 1 and steerable rear wheels 2 are driven, and two-wheel drive driving in which only the front wheels 1 are driven; This braking device operates in conjunction with switching so that the rear wheel brake 3 of the rear wheels 2 is applied during drive driving, and the rear wheel brake 3 is not applied during four-wheel drive driving.