JPH0132491Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is based on a pair of left and right lower lift arms that swing up and down around a horizontal axis, and a pair of left and right lowers that are supported in a suspended state via a lift rod. The machine is equipped with a three-point link mechanism consisting of a link and a top link located above the lower link, and the horizontal tilt angle of the machine is detected on the side of the traveling machine connected to the ground work equipment via this three-point link mechanism. One of the lift rods is extended and retracted in order to operate toward a posture corresponding to a control target signal set based on the horizontal inclination angle of the traveling machine detected by the sensor. A rolling control mechanism is provided to adjust the ground posture of the ground work device, and a sensor is provided to detect the swing angle of the lift arm, and based on the detection result of the sensor, the device corresponds to the unit horizontal inclination of the traveling main body. A rolling control mechanism comprising a correction means for outputting a corrected control target signal obtained by correcting the control target signal to the rolling control mechanism so that the amount of rolling operation of the ground work device is maintained at a predetermined value. The present invention relates to a work vehicle, and specifically relates to a technique for setting a ground work device in a position parallel to a traveling main machine.

[Prior art] The work vehicle with the above configuration is equipped with left and right tilt sensors on the machine side, so rolling control can be performed no matter what kind of work equipment is attached to the three-point linkage mechanism, Unlike the conventional method in which a rolling detection sensor was installed to control the rolling of the work equipment to the desired left/right tilted position, there is no need to replace and set the rolling detection sensor each time the work equipment is replaced, making it convenient. It has characteristics that can be used for

Conventionally, as a technique for setting the ground work device in a posture parallel to the traveling main machine (hereinafter referred to as parallel control), there is a control lever of a hydraulic cylinder that raises and lowers the lift arm of the three-point linkage mechanism. It has been proposed that the control lever is provided with a mechanism such as a limit switch that detects that the control lever is operated to the highest position, and that the rolling control is forcibly inhibited by an ON signal from this switch.

As shown in FIG. 5, in the case where the lower link 4' is suspended from the lift arm 3' via the lift rod 7',
When the lift arm 3' is moved up and down, the connection angle β between the lift rod 7' and the lower link 4' changes.

When the connection angle β changes in this manner, a difference occurs in the amount of swing of the lower link 4' with respect to the unit expansion and contraction amount of the lift rod 7', resulting in an error in the rolling operation. Therefore,
In the rolling control system, the correction means is configured to perform correction based on the swing angle of the lift arm 3' to prevent the occurrence of errors.

Incidentally, the swing amount of the lower link 4' with respect to the unit expansion/contraction amount of the lift rod 7' becomes smaller as the connection angle β approaches a right angle, and is basically unrelated to the swing angle α of the lift arm 3'. (Can be understood by drawing).

[The problem that the idea aims to solve]

In addition, the parallel control allows the ground work equipment to be raised significantly when the aircraft makes a U-turn or when it is not operating, and is forced to take a position parallel to the main machine regardless of the aircraft's inclination angle. This is to prevent rolling control while the vehicle is running, and to prevent the work device from accidentally coming into contact with the ground when not working.

However, in the conventional parallel control mechanism, the parallel control is activated by mechanically detecting the operating position of the lift arm elevation operating lever, so that the operating lever is If the lift arm is not operated securely to the highest position, the attitude of the ground work equipment may not be parallel even if the lift arm is raised, and if this is done, there is a risk of the aircraft falling during a turn.
Further, it is necessary to conduct wiring from the switch to the control section of the rolling control mechanism, and the mechanism for detecting the lever position also becomes complicated.

The present invention effectively utilizes the mechanism equipped to perform highly accurate rolling control as described above, and has a simple structure that omits the operating position detection means of the lift arm elevation control lever, allowing from rolling control to parallel control. The purpose is to improve safety by automatically switching to

[Means to solve the problem]

A feature of the present invention is that in a working vehicle with a rolling control mechanism that has a correction means as described above, when the sensor detects a swing of the lift arm by a predetermined angle or more, the traveling main body Regardless of the rolling attitude of the ground work equipment relative to It has a forced restoration means for outputting to the control mechanism, and its construction and effects are as follows.

[Effect]

If the above characteristics are configured as shown in FIGS. 2 and 3, for example, when the lift arm 3 is operated in the upward direction to raise the ground work 2,
A comparator A15 compares a voltage _V0 corresponding to a preset swing angle of the lift arm 3 with a voltage from a sensor _S2 that detects the swing angle of the lift arm 3, and the comparator A15 When it is detected that the swing angle has reached a preset swing angle or more, the switch circuit SW ₂ is switched by the output signal from the comparator A15, so that the ground work device 2 is in a parallel posture with respect to the traveling machine body 1. The control target signal VθH corresponding to the above is output to the rolling control mechanism A via the switch circuit _SW2 .

That is, in the present invention, the level of the ground work device 2 is detected based on the detection result of the sensor S ₂ provided for obtaining the correction control target signal, and a switch is provided that is linked to the operating lever as described above. Therefore, parallel control becomes possible.

In addition, in Fig. 3, sensor S ₂ and multiplier
A ₂ is collectively referred to as correction means E, and the sensor
_S2 , the comparator A15, and the switch circuit _SW2 are collectively referred to as forced restoration means F, and the sensor _S2 is shared by each of the means E and F.

[Effect of idea]

Therefore, a manually operated switch for switching between rolling control and parallel control is not required, and the mechanism is simplified by making the sensor that was originally provided for correcting the control also serve as a dual-purpose sensor. This has made it possible to perform posture control with high precision and safety.

〔Example〕

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

As shown in FIGS. 1 and 2, a tilling rotary 2, which is an example of a ground work device, is connected to a pair of left and right lift arms 3, 3' at the rear of a tractor 1 as a traveling main machine. A working machine that is connected to the tractor 1 through a three-point link mechanism 6 consisting of lower links 4, 4' and a top link 5 so that it can be driven up and down while rolling integrally with the tractor 1. A sensor S1 is attached to the tractor ₁ side for detecting the accompanying rolling of the tilling rotary 2, that is, the horizontal tilt angle θ with respect to the horizontal, and based on the detection by this sensor S1, the corresponding lower links 4, 4' By expanding and contracting one 7' of the pair of left and right lift rods 7, 7' that connect the lift arms 3, 3' with the left and right lift rods 7, 7' via the hydraulic cylinder 8, the left and right attitude of the tilling rotary 2 relative to the ground can be adjusted to the set attitude (horizontal). A rolling control mechanism A is provided that automatically corrects the posture so that the posture is adjusted.

The three-point linkage mechanism 6 is configured so that the tilling rotary 2 can be raised and lowered with respect to the tractor 1 by driving its lift arms 3 and 3' up and down by a hydraulic cylinder 9, A sensor _S2 for detecting the lift angle α of the lift arms 3, 3' with respect to the tractor 1 is provided at the lift arm fulcrum.

On the other hand, the hydraulic cylinder 8 that extends and contracts the lift rod 7' has a sensor that detects the amount of extension and contraction.
_S3 is provided and is arranged to detect the length displacement of the lift rod 7'.

The sensors S ₁ and S ₂ are rotary potentiometers, and are configured to generate voltages V ₁ and V ₂ corresponding to the rotation angles θ and α, respectively. In particular, the sensor S ₁ is A device that is rotated by a hanging weight that can swing left and right is used.

On the other hand, the sensor S ₃ is a linear sliding type potentiometer, and is configured to generate a voltage V ₃ corresponding to the amount of expansion/contraction 1 of the hydraulic cylinder 8.

Next, the detection voltages V ₁ of the sensors S ₁ , S ₂ , S ₃ ,
A control circuit for adjusting the left and right tilted posture of the tilling rotary 2 based on V ₂ and V ₃ will be explained in detail with reference to FIG. 3.

The control circuit 10 basically converts the aircraft inclination angle θ detected by the sensor S ₁ into a target control amount corrected according to the lift arm angle α detected by the sensor S ₂ and the sensor S ₃ . The hydraulic cylinder 8 is configured to be driven so that the amount of expansion and contraction of the hydraulic cylinder 8 detected by the .

That is, the output voltage of the preamplifier A ₁ that converts the output voltage V ₁ of the sensor S 1 into a voltage V θ that can determine the magnitude and direction of the displacement amount of the aircraft inclination angle θ from the reference (horizontal state θ = ₀ ). A gain converter 11 for changing the control gain according to the displacement direction of Vθ with respect to the reference of the tilt angle θ, an output voltage V|θ| of this converter 11, an output voltage V ₂ of the lift angle detection sensor S ₂ A multiplier that generates a voltage V〓, which is obtained by dividing the voltage V|θ|, by multiplying by the lift angle α
A ₂ , the voltage V〓 corresponding to the lift angle α output from the multiplier A ₂ and the output voltage Vθ of the amplifier A ₁ are added and subtracted to obtain the target voltage of the cylinder length corresponding to the expansion/contraction amount l of the hydraulic cylinder 8. an operational amplifier A ₃ for converting the output voltage V ₃ of the sensor S ₃ into _a voltage V _l corresponding to a cylinder length of the same scale as the scale of _the target voltage V _z ; A comparator group 13 generates a control signal for driving the electromagnetic valve 12 of the hydraulic cylinder 8 by comparing the voltage _Vz and the detected voltage _Vl , and the output voltage _V2 of the lift angle detection sensor _S2 and the predetermined lift angle. A comparator that compares α ₀ with a reference voltage V ₀ and outputs an “H” level signal C ₅ when the output voltage V ₂ becomes higher than this reference voltage V ₀
The output signal _C5 of _A15 causes the comparator group 1 to
A switch circuit SW ₂ switches the target voltage V _z input to the output of the operational amplifier A ₃ to the reference voltage Vθ _H corresponding to the state in which the aircraft is horizontal (θ = 0), and the output signal of the comparator group 13. Receiver solenoid valve 1
A driver circuit 14 for driving 2 is provided,
Controlling the amount of expansion and contraction of the hydraulic cylinder 8 so that the target voltage V _z converted based on the body inclination angle θ of the sensor S ₁ and the detected voltage V _l corresponding to the cylinder length of the sensor S ₃ are equal; Therefore, the attitude of the tilling rotary 2 is maintained horizontally regardless of the horizontal inclination and lift angle of the tractor 1, and when the lift arms 3, 3' are raised to the predetermined angle α ₀ or more, the body inclination angle is Regardless of θ, the attitude of the tilling rotary 2 is forced to be parallel to the tractor 1.

The preamplifier A ₁ converts the voltage V ₁ output from the sensor S ₁ into a voltage Vθ proportional to the tilt angle θ with respect to a reference voltage Vθ _H corresponding to the state where the aircraft is horizontal (θ = 0). It is configured as expected.

That is, when the output voltage Vθ is larger than the reference voltage Vθ _H , the aircraft corresponds to an upward movement to the right (θ>0), and when it is smaller, the aircraft corresponds to an upward movement to the left (θ<0).

The gain converter 11 inverts and amplifies the voltage in the negative range (Vθ< _VθH ) with a predetermined gain _K1 with respect to the reference voltage _VθH of the output voltage Vθ of the preamplifier _A1 , and An inverting amplifier _A5 whose output voltage is 0V in the range (Vθ≧ _VθH ) and a voltage in the positive range (Vθ> _VθH ) with a predetermined gain _K2 with respect to the reference voltage VθH of the voltage Vθ _. A non-inverting amplifier A ₆ which performs inverting amplification and whose output voltage is 0 V in the negative range (Vθ≦Vθ _H ), this amplifier A ₆ and the amplifier A ₅
an adder A ₇ that synthesizes the output voltages V|+θ|, V|−θ|, and a reference voltage Vθ _H of the detection voltage Vθ.
A comparator that determines the direction of the inclination angle θ and outputs a logic signal _C1 that is “H” level when rising to the right (θ≧0) and “L” level when rising to the left (θ<0). A ₈ , which constitutes a circuit equivalent to an absolute value circuit.

The operational amplifier _A3 outputs a voltage Vθ corresponding to the tilt angle θ and an output voltage V| of the gain converter 11.
θ｜ is a multiplier based on the output voltage V ₂ of sensor S ₂
Voltage V 〓 corrected according to lift angle α by A ₂
An analog switch SW ₁ is provided to switch the addition polarity according to the direction of the tilt angle θ, and as shown in FIG _. It happens.

The comparator group 13 is provided with four comparators A ₉ , A ₁₀ , A ₁₁ , A ₁₂ having the following configuration, and a control signal C ₂ for extending the hydraulic cylinder 8,
It is configured to output a control signal C ₃ for reducing the frequency and a control signal C ₄ for switching the oscillation frequency of the oscillator 15 of the driver circuit 14 .

That is, the comparators A ₉ and A ₁₀ are connected to the voltages V _z ,
Reference voltage with the difference between V _l set as dead band width
They compare Vθ ₂ and Vθ ₁ and output control signals C ₂ and C ₃ , respectively.

The comparators A ₁₁ and A ₁₂ are connected to the voltages V _z ,
The difference in V _l is compared with the reference voltages VD ₁ and VD ₂ set outside the reference voltages Vθ ₂ and Vθ ₁ with 0V as the center, and the range of these reference voltages VD ₁ and VD ₂ (VD ₁ < | V _z −V _l
In order to output the “H” level control signal C ₄ when there is a voltage difference |V _z −V _l | in |<VD ₂ ),
Logical product (AND) processing is performed by AND gate _G1 .

The driver circuit 14 of the electromagnetic valve 12 includes:
An oscillator 15 provided to drive the electromagnetic valve 12 intermittently, and an output of the oscillator 15 is opened and closed.
AND gates G ₂ and G ₃ and solenoid drive circuits A ₁₃ and A ₁₄ for intermittently driving the electromagnetic valve 12 by the oscillator 15 via the gates G ₂ and G ₃ are provided.

The gates G ₂ and G ₃ are connected to the comparators A ₉ and
The output of the oscillator 15 is input to one of the drive circuits A ₁₃ and A ₁₄ by control signals C ₂ and C ₃ output from A ₁₀ .

Further, the oscillator 15 is configured to be able to switch its oscillation frequency, and the comparators A ₁₁ and A ₁₂
The control signal C ₄ is output through the AND gate G ₁ of
The configuration is such that the oscillation frequency can be switched according to the following.

This switching of the oscillation frequency is performed at the aircraft inclination angle θ
When adjusting the posture of the tilling rotary 2 by expanding and contracting the hydraulic cylinder 8 according to the angle of inclination θ, the expansion and contraction speed of the hydraulic cylinder is slowed to prevent the posture from changing suddenly It is set up for this purpose.

On the other hand, when the control valve (not shown) of the hydraulic cylinder 9 for lifting the lift arm is switched to the up position, the lift arm is raised, and the lift angle α becomes equal to or larger than the predetermined angle α ₀ , the comparator Switch circuit SW ₂ by output C ₅ of A ₁₅
is automatically switched so that the reference voltage _VθH is input to the comparator group 13 instead of the target voltage from the operational amplifier _A3 .

Therefore, when the machine makes a U-turn on a headland or when the tilling rotary 2 is raised for non-working travel, the tilling rotary 2 is automatically corrected to the reference posture parallel to the tractor 1.

Further, SW ₃ is an automatic/manual changeover switch provided to manually vary the attitude (horizontal inclination) of the tilling rotary 2 with respect to the tractor 1, and P is a potentiometer as a means for setting the inclination angle.

Further, the switch circuit SW ₂ is configured to be able to be switched manually, so that the tilling rotary 2 can be set to the tractor 1 regardless of the lift angle α when adjusting the reference posture, etc.
It may also be possible to take a reference posture parallel to .

As shown in FIG. 3, in this embodiment, the sensor S ₂ and the multiplier A ₂ are collectively referred to as a correction means E.
The sensor S ₂ , the converter A 15, and the switch circuit SW ₂ are collectively referred to as forced restoration means F, and the former corrects rolling control based on the swing angle α of the lift arm 3, and the latter corrects the rolling control based on the swing angle α of the lift arm 3. When the tilling rotary 2 is raised above a predetermined level, the tilling rotary 2 is operated to be parallel to the traveling main machine 1.

[Brief explanation of the drawing]

The drawings show an embodiment of a working vehicle with a rolling control mechanism according to the present invention, in which FIG. 1 is an overall side view, FIG. 2 is a perspective view of main parts, and FIG. 3 is a block diagram of the control mechanism.
FIG. 4 is a characteristic diagram of the control gain, and FIG. 5 is a side view showing the connection angle between the lift rod and the lower link. 1... Traveling main machine, 2... Ground work device, 3,
3'...Lift arm, 4,4'...Lower link, 5...Top link, 6...Three-point link mechanism, 7,7'...Lift rod, A...Rolling control mechanism, E...Correction means , F...forced restoring means, _S1 ...body tilt detection sensor, _S2 ...lift angle detection sensor, θ...incline angle, α...lift angle.

Claims (1)

[Scope of utility model registration request] A pair of left and right lower links 4, 4' are supported in a suspended state via lift rods 7, 7' for a pair of left and right lift arms 3, 3' that swing up and down around a horizontal axis, and this lower link The machine is equipped with a three-point linkage mechanism 6 consisting of a top link 5 located above 4 and 4', and the machine is tilted left and right towards the side of the traveling main machine 1 connected to the ground work device 2 via this three-point linkage mechanism 6. A sensor S ₁ for detecting the angle θ is provided, and the lift rod is operated toward a posture corresponding to a control target signal set based on the left-right tilt angle θ of the traveling main body 1 detected by the sensor S ₁ . a sensor S for detecting the swing angle α of the lift arm 3; ₂ , and based on the detection result of this sensor _S2 , the control target signal was corrected so that the amount of rolling operation of the ground work device 2 corresponding to the unit horizontal inclination of the traveling main machine 1 was maintained at a predetermined value. The working vehicle is equipped with a rolling control mechanism and includes a correction means E that outputs a correction control target signal to the rolling control mechanism A, and the sensor _S2 detects the movement of the lift arm 3 by a predetermined angle or more. When motion is detected, the ground working device 2 is set to a posture parallel to the traveling main machine 1, regardless of the rolling posture of the ground working device 2 with respect to the traveling main machine 1, so that the parallel posture is supported. A work vehicle with a rolling control mechanism, comprising forced restoration means F for outputting a control target signal to the rolling control mechanism A instead of the corrected control target signal.