JPH079892A - Propulsion control mechanism for hst driven tractor - Google Patents

Abstract

PURPOSE:To eliminate the occurrence of an improper cultivating pitch due to a drop in the speed of a cultivator shaft for soil resistance acting on a rotary cultivator, and an increase in the travel speed of a cultivating rake over the driving speed of the cultivator for a propulsive force from the soil. CONSTITUTION:A brake is intermittently actuated to control a travel wheel, so as to keep a ratio of a value detected with a PTO shaft speed detecting sensor S1 to a value detected with an axle speed detecting sensor S2 identical to a preset value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for controlling a propulsion tendency of a tractor driven by a rotary cultivator driven by an HST transmission.

[0002]

2. Description of the Related Art Conventionally, the rotation speed of a rotary cultivator mounted on the rear part of a tractor and the rotation speed of wheels of a tractor unit are both mechanically transmitted from an engine output shaft of the tractor unit. , Had a constant relationship. That is, the vehicle speed and the number of rotations of the tilling shaft are in a proportional relationship, and as a result, a constant tilling pitch could be maintained even if the vehicle speed changed.

[0003]

However, in recent years, there has been an increasing demand for a tractor that is driven and driven in a continuously variable manner via an HST transmission device because of advantages such as stability and operability at low speed traveling. . In the case of this HST-driven tractor, the driving force of the traveling wheels of the tractor main unit is transmitted from the engine output shaft through the hydraulic pump and hydraulic motor of the HST transmission, and this hydraulic system is used to drive the traveling wheels. The running resistance received is reduced. That is, since the hydraulic pressure is always kept constant, the force for driving the hydraulic motor remains almost unchanged. Therefore, even when the tiller claw of the rotary tiller receives a strong resistance from the field and the rotation speed drops, the traveling wheels themselves maintain a strong driving force without interlocking with it, and the resistance from the field is reduced. Since the rotary cultivator when strongly receiving it gives a stronger propulsive force to the tractor main body side, the wheel rotation speed becomes larger than the rotation speed of the cultivating shaft of the rotary cultivator, and both of them were conventionally constant. Since the relationship cannot be kept constant and the tilling pitch is not constant, good tilling work cannot be obtained. In addition, the forward drive of the tractor is suddenly promoted,
It is dangerous for workers.

[0004]

The present invention uses the following means in order to solve the above problems. That is, the HS driven to travel via the HST transmission
In the T drive type tractor, the brake is intermittently applied so that the rotation speed of the rotary tiller and the vehicle speed always have a constant proportional relationship.

[0005]

[Function] Since the traveling speed of the tractor is brake-controlled and interlocked with a change in the rotation speed of the rotary tiller, a constant relationship is maintained, so that the tilling pitch is kept constant.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the configuration of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a drive structure of a tractor and a rotary cultivator, and FIG. 2 is a configuration diagram showing a propulsion control mechanism of the tractor.

The drive structure of the tractor T and the rotary cultivator R will be described with reference to FIG. In the tractor T, the output shaft 1 of the engine E is inserted into the transmission case MC via the main clutch 2, and the output shaft 3 is input from the transmission case MC to the hydraulic pump P of the HST transmission 4. By inserting the motor shaft 5 of the hydraulic motor M driven by the hydraulic pump P into the differential gear device 6,
The rear wheel RW is driven. On the other hand, the rotary work machine R is mounted so as to be able to move up and down by a work machine mounting link mechanism at the rear part of the tractor, and further, the PTO shaft 8 from the mission case MC via the PTO shaft transmission 7 and the universal joint 9 to the rotary cultivator. R drive shaft 1
It is connected to 0 and is configured to drive the tiller shaft 11 of the rotary tiller.

In the HST driven tractor T equipped with the rotary cultivator R as described above, the PTO shaft rotation speed detection sensor S1, the axle rotation speed detection sensor S2 and the cultivator speed setting device S shown in FIG. 2 are provided. To do. The PTO
The shaft rotation speed detection sensor S1 is a sensor that detects the rotation speed of the PTO shaft 8, and the axle rotation speed detection sensor S2 is a sensor that detects the rotation speed of the axle of the rear wheel RW. The tilling speed setting device S sets the vehicle speed and the tilling shaft rotation speed, that is, the ratio of the PTO shaft rotation speed and the rear wheel axle rotation speed to a constant value, regardless of changes in the vehicle speed and the rotation speed of the tilling shaft. It is a setter for the purpose of keeping the tilling pitch constant. The controller C is configured to input the detected values of the sensors S1 and S2 and the set value of the setter S into the controller C.

When the ratio of the detection values of both sensors S1 and S2 is different from the setting value of the tilling speed setting device S, that is,
When the resistance applied to the tilling claw of the rotary tiller R becomes strong and the PTO shaft rotation speed decreases, the tiller speed setting device S
The brake is intermittently applied in order to reduce the rotational speed of the rear wheel axle so as to match the ratio set in. That is, the controller C detects the sensors S1 and S2.
The PWM drive signal is transmitted to the electric motor of the brake solenoid 12 so as to match the ratio of the detected value with the set value S of the setter, and the brake 13 is intermittently applied by repeating ON / OFF of the motor to rotate the axle. Number detection sensor S
When it is confirmed that the rear wheel axle rotation speed detected at 2 matches the ratio set at the tilling speed setting device S with respect to the detection value detected at the PTO shaft rotation speed detection sensor S1. , The brake braking is stopped. in this way,
The brake control reduces the traveling speed according to the decrease in the number of rotations of the tiller shaft of the rotary tiller, and holds the ratio set by the tiller speed setting device S, so that the tiller speed is kept constant,
Good plowing work can be obtained.

Brake braking is performed by PWM as described above.
In the drive control method, the transmission type brake solenoid 12 is turned on and off intermittently, in order to prevent a worker from danger due to sudden braking. The ON / OFF interval of the brake solenoid 12, that is, the pulse width of the pulse signal sent from the controller C to the electric motor of the brake solenoid can be changed, and the brake braking time can be changed by the change.

[0011]

The present invention has the following effects by being configured as described above. That is, in an HST-driven tractor equipped with a rotary tiller, the tiller pitch is kept constant because the ratio of the tiller shaft to the traveling wheel rotation speed of the rotary tiller is originally constant, but the rotary tiller is fixed. The field braking force applied to the machine reduces the number of rotations of the tiller axis of the tiller, and the driving force causes the number of traveling wheels to increase compared to the number of rotations of the tiller. Since the wheels are braked and returned to a constant ratio, the tilling pitch is kept constant and good tilling work can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a drive structure of a tractor and a rotary tiller.

FIG. 2 is a configuration diagram showing a propulsion control mechanism of a tractor.

[Explanation of symbols]

 T Tractor R Rotary Tiller S1 PTO Shaft Rotation Speed Detection Sensor S2 Axle Rotation Speed Detection Sensor S Tillage Speed Setting Device 12 Brake Solenoid 13 Brake

Claims (1)

[Claims] 1. An HST drive type tractor that is driven to travel via an HST transmission, and is configured to intermittently apply a brake so that a rotation speed of a rotary cultivator and a vehicle speed always have a constant proportional relationship. A propulsion control mechanism for an HST-driven tractor characterized in that