JPH11168936A - Reaping height controller of combine harvester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reaping height controller of a combine harvester capable of making up for the low reliability of the results of detection with a noncontact type sensor such as an ultrasonic sensor by detection of the quantity of variation related to pitching which is a variation in the front and rear direction of a mobile machine body and designed not to cause a delay in lifting and lowering control of a reaping pretreatment device and the damage to parts or the like of the reaping pretreatment device. SOLUTION: This reaping height controller of a combine harvester is obtained by liftably and lowerably installing a reaping pretreatment device through a hydraulic cylinder at the front end of a mobile machine body, providing a pitching sensor which is capable of detecting the quantity of variation related to the pitching in the front and rear directions on the side of the mobile machine body, on the other hand, providing an ultrasonic sensor for detecting the height from the ground surface in the reaping pretreatment device and performing the lifting and lowering control related to the pitching for lifting and lowering the reaping pretreatment device in the direction opposite the direction of pitching of the mobile machine body only within a prescribed time (S4: yes) when the quantity of variation in pitching exceeds a prescribed value from the results' of detection (S1) by a pitching sensor (S2: yes).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a harvesting pre-processing device mounted on the front of a traveling body of a combine so as to be able to move up and down, and a detection signal of a non-contact type cutting height sensor and a longitudinal pitching mounted on the traveling body. The present invention relates to a technique for automatically adjusting the cutting height from a field scene in consideration of both the amount and the amount.

[0002]

2. Description of the Related Art Conventionally, as a cutting height sensor device in a combine, Japanese Patent Publication No. 63-32410,
The ultrasonic sensor, which is a non-contact type sensor device disclosed in JP-A-300833 and the like, can set a wide detection range of the height of the ground with respect to the field scene, but detects the straw debris and the like in the field scene and detects the field. There is a problem that the reliability remains, such as the height of the surface being erroneously sensed.

On the other hand, the construction of a grounding type cutting height sensor device is disclosed in Japanese Utility Model Laid-Open Publication No. 51-153227 and JP-A-7-274650.

[0004]

However, in the grounding-type sensor device, a sensing lever associated with a sensor body such as a limit switch is extended rearward and downward, and a grounding portion (sled portion) is disposed at the rear end. The limit switch was turned on within a certain range of vertical movement of the sled part →
It is only possible to detect a height position where OFF or OFF → ON. For example, even when the traveling body is folded forward, for example, over a ridge in a field or being fitted into a recess,
If the ground-type sensor device does not come into contact with the ground, the mowing pre-processing device will not be raised upward, so the timing of the raising operation will be delayed, and the grounding body of the ground-type sensor device and the lower end part of the mowing pre-processing device will be described. However, there was a problem that it was easily broken. Of course, it has been difficult to detect sudden irregularities in the field even with the ultrasonic sensor.

The present invention compensates for the low reliability of the detection result of a non-contact type sensor such as an ultrasonic sensor by detecting a variation related to pitching which is a variation in the front-rear direction of the traveling machine body. It is an object of the present invention to provide a cutting height control device in a combine which prevents a delay in raising / lowering control of a combine and prevents damage to components of a pre-cutting device.

[0006]

In order to achieve the above object, a cutting height control device in a combine according to the present invention is configured such that a cutting pre-processing device can be moved up and down by a lifting drive means with respect to a front portion of a traveling body. A cutting height control device in a combine configured to operate the lifting / lowering driving means by a detection signal of a non-contact type cutting height sensor that detects a ground height of the cutting pretreatment device; A pitching sensor capable of measuring a variation in pitching in the front-rear direction of the traveling body is provided, and when it is determined that the variation in pitching based on the detection result of the pitching sensor is equal to or greater than a predetermined value, the non-contact cutting height is determined. The operation of the elevation drive means may be controlled in the direction opposite to the pitching direction of the traveling body, prior to the elevation control based on the detection signal of the sensor. It is those that you have configured.

[0007]

FIG. 1 is a side view of a combine having a pair of right and left traveling devices 2 provided with a traveling crawler 2a, and FIG. 2 is a diagram showing a combine. , FIG. 3 is a front view of the combine, FIG. 4 is a side view of an elevating position sensor for detecting an ascent / descent position between the mowing pre-processing device and the traveling aircraft, and FIG. 6 is a skeleton diagram of power transmission. 7 is a functional block diagram of the hydraulic circuit and the control device.

As shown in FIGS. 1 to 3, a threshing device 3 having a conventionally known structure is mounted on the left side in the traveling direction of the traveling machine 1 and a single-acting type is mounted on the front of the traveling machine 1. A cutting pretreatment device 4 that can be moved up and down by a hydraulic cylinder 9 is arranged. A clipper-type cutting blade device 5 is disposed below the lower frame of the pre-cutting device 4, and a grain stem raising device 6 for six rows is disposed in front of the clipping blade device 5. A grain stalk transport device 8 is arranged between the feed chain 3 and the front end of the feed chain 7 for supplying the grain stalk to the grain stalk raising device 6.
In the lower front part of the tree, a weeding body 10 for six rows protrudes. A driver's cab 11 is arranged at the front right side of the traveling machine body 1, and a grain tank 12 is arranged at the rear side. In the cereal stalk transport device 8, the stalk root raised by the cereal stalk raising device 6 is conveyed while pinching the root portion of the cereal stem, and the root portion of the feed chain 7 is inherited by the feed chain 7.

As shown in FIGS. 4 and 5, the base of a vertically downwardly inclined elevating and lowering cylinder frame 14 having a front end mounted on the pre-cutting device 4 is fixed to a horizontal cylinder 15, and the horizontal cylinder 15 is mounted on a traveling machine body. 1 is rotatably supported by a plurality of bearing brackets 16 (one of which is not shown) provided at a front portion of the vehicle body 1 and receives power from an engine 35 on the traveling machine body 1 in each of the horizontal cylinder 15 and the lifting cylinder frame 14. Transmission shafts 17 and 19 arranged in the inner diameter portion,
Power is transmitted to each part of the pre-cutting device 4 via the bevel gear pair 18 and the like. The lifting pre-processing device 8 is driven up and down by a lifting hydraulic cylinder 9 mounted between the middle part of the lifting cylinder frame 14 and the traveling machine body 1.

As shown in a skeleton diagram (FIG. 6) showing the power transmission system of the combine, one of the outputs from the engine 35 is supplied to a bottom conveyor 37 and a vertical conveyor 38 in the grain tank 12 via a clutch 36. And then to a screw conveyor (not shown) in the discharge auger 28. The other output from the engine 35 is transmitted via the power branching mission 39 to the handling cylinder drive shaft 40 and the sorting drive shaft 4.
1. A hydraulic pump for traveling The power is transmitted to a drive shaft 43 to a hydraulic motor type (HST type) traveling drive unit 42 and to a constant speed rotation drive shaft 44 to a pre-cutting device 4. The other output from the engine 35 turns ON / OFF the power transmission via the threshing clutch 48a in the power branching mission 39, and the handling cylinder 13 via the handling cylinder drive shaft 40 or the sorting drive shaft 41. And the processing cylinder 29, the first gutter screw conveyor 26a, the Karino Juan 27, the second gutter screw conveyor 26b and the second reduction conveyor 25, the straw chain 3
1, transmitted to the suction fan 30 and the straw cutter 33.

On the other hand, from a cutting and tuning drive shaft 45 output from the (HST type) traveling drive unit 42, a cutting shaft 47 is transmitted via a one-way clutch 45a (which can be transmitted only when the traveling drive unit is rotating forward) and a tuning clutch 46. Power to
It is transmitted directly to the feed chain 7. The power transmission to the pre-cutting device 4 is turned ON / OFF via a cutting clutch 49 provided on the cutting shaft 47. In order to turn on / off the threshing clutch 48a, the tuning clutch 46, the inflow clutch 48, and the reaping clutch 49, respectively, a clutch actuator such as an electromagnetic solenoid corresponding to each clutch is turned on / off. . The tuning clutch 46 may be a tension clutch that cuts off the power by tensioning and relaxing the tension of the belt. Therefore, as described later, when the vehicle speed tuning control is prohibited (stopped) or the like, power is transmitted to the reaping shaft 47 via the constant-speed rotation drive shaft 44 of the power branching mission 39, and the HST traveling drive unit 42 The one-way clutch 45a idles when the output rotation speed of the cutting synchronization drive shaft 45 is lower than the rotation speed from the constant speed rotation drive shaft 44 or when the cutting synchronization drive shaft 45 rotates in the retreating direction of the combine. .

The swash plate of each hydraulic pump or the like of the HST type (in which a mechanical speed change mechanism is incorporated in a stepless speed change mechanism using two hydraulic motors and two hydraulic pumps) of the traveling drive unit 42 is adjusted to reduce the vehicle speed. Main shift lever 85 for step shifting
Is a seat 11a in the cab 11 as shown in FIG.
Is turned forward and backward by the side operation unit, and when it is tilted forward with respect to the neutral position (stop position) in a substantially vertical posture, it is the forward position. The larger the inclination angle with respect to the vertical, the higher the vehicle speed. When the vehicle is tilted backward, the vehicle retreats, and the vehicle speed increases as the angle of inclination increases.

A sub-transmission lever 86, which is also disposed on the side operation section of the seat 11a, controls an actuator such as a transmission motor for operating a mechanical transmission mechanism (not shown) provided in the HST type traveling drive section 42. When the sub-transmission lever 86 is switched to each of the road traveling mode, the standard operation mode, and the low-speed operation mode, the microcomputer-based control unit (controller unit) 70 mounted on the combine unit issues a command. The output (horsepower) and the number of revolutions of the traveling drive unit 42 adapted in the work mode can be set and maintained in a predetermined range.

When a normal harvesting and threshing operation is performed while the traveling machine 1 is traveling forward (in the low-speed operation mode and in the standard operation mode), the power branching mission 39 is used.
OFF (power cutoff) the inflow clutch 48 at
The threshing clutch 48a, the tuning clutch 46, and the reaping clutch 49 are turned on (power connection), and while monitoring the detection values of the fuel injection amount sensor and the vehicle speed sensor, the reaping of the rotational speed tuned to the output of the traveling drive unit 42 is performed. The mowing shaft 47 is driven via the tuning drive shaft 45 to tune and drive the pre-cutting device 4 and the feed chain 7, while the handling cylinder drive shaft 40 and the sorting drive shaft 41 are driven to handle the handling cylinder 13 and the processing cylinder 2.
9. Driving the blower fan, the Karaoke fan 27, the swing sorting mechanism, and the like.

When the traveling machine 1 is to be stopped or retreated when the traveling machine is to change direction during the harvesting and threshing work in the field, when the drive of the pre-cutting device 4 and the feed chain 7 is stopped. The tuning clutch 46 and the inflow clutch 48 are turned off. To drive only the feed chain 7, the reaping clutch 49 must be turned off.
Change to F. In this case, power is not transmitted to the pre-cutting device 4, but is transmitted only from the power branching mission 39 to the feed chain 7 via the cutting shaft 47.

The ultrasonic sensor 20 as a non-contact type cutting height sensor for detecting the cutting height by detecting the ground height between the pre-cutting device 4 and the field scene is provided by the culm raising device 6. The transmitter (horn) of the transmitter 20a and the receiver of the receiver 20b in the ultrasonic sensor 20 are arranged on a field scene as shown in FIG. Place it so that it faces. Ultrasonic sensor 20
When the installation height of the cutting blade 5 is different from the installation height of the cutting blade 5, the detection value of the cutting height is obtained by a predetermined conversion from the detection value of the ultrasonic sensor 20.

On the other hand, the elevation position sensor 22 is for detecting the relative height between the traveling machine body 1 and the pre-cutting device 4, and in this embodiment, as shown in FIGS. The rotation arm 23 of the rotation position sensor 22 of the rotation potentiometer type fixed to the bearing bracket 16 is brought into contact with a sensor shaft 24 fixed to the outer surface of the horizontal cylinder 15 to detect the rotation angle θ of the horizontal cylinder 15. Thereby, the rotation angle of the elevating cylinder frame 14 and, consequently, the relative elevating position of the pre-cutting device 4 with respect to the traveling machine 1 (the elevating position of the machine body) can be detected. The setting value by the cutting height setting unit 73 described later corresponds to a predetermined value in the detection value of the elevation position sensor 22.

When mounted on the traveling body 1, the amount of pitching variation (the amount of pitching (the amount of vertical rotation of the traveling body in the front-rear direction)) which is the amount of variation in the vertical inclination of the traveling body 1, and the per unit time The pitching sensor 92 for measuring the pitching variation (pitching angular velocity) is installed in the cockpit 11 or the like. The pitching sensor 92 may be any sensor that can measure the forward and backward rotation and swing of the traveling body 1. For example, when an angular velocity sensor using two piezoelectric elements is used, the pitching angular velocity is a detection value. The pitching amount may use the value obtained by integrating the pitching angular velocity with respect to time. The value obtained by integrating the detected values of the gyro-type angular velocity sensor, piezoelectric acceleration sensor, servo acceleration sensor, strain gauge acceleration sensor, and semiconductor diffusion acceleration sensor over time can be used as the pitching angular velocity. Can be

FIG. 7 shows a functional block diagram of a control device 70 for executing the cutting height control.
An electronic control device such as a microcomputer, not shown, a central processing unit (CPU) for executing various arithmetic processing and control, a read-only memory (ROM) storing a control program, various detected values, Read / write memory (RAM) for temporarily storing data etc.,
A nonvolatile memory (flash memory) for holding stored data even when the power of the control device is turned off, a clock as a timer function, an interface, a bus, and the like are provided.

An ultrasonic wave is transmitted to the transmitter 20a of the ultrasonic sensor 20 at an appropriate time interval T1 through a transmission drive circuit 71 in accordance with a command from the control device 70, and a reflected wave reflected by an object or the like is reflected. Is received by the receiver 20b, and the detection signal is input to the control device 70 via the reception amplifier circuit 72. The detection signal of the elevation position sensor 22 is also A /
The control device 70 is provided via the D converter at each of the time intervals T1.
To enter.

Further, the pitching sensor 92, a variable resistance type (volume type) cutting height setting device 73, a three-position detection type manual switch 76 for performing a threshing operation in a manual mode, and an automatic control mode for the same operation. In order to change the vertical movement amount and / or vertical movement speed of the pre-cutting device 4 to a smaller side when the manual operation is performed, the operator depresses the foot switch 74 to perform ON / OFF operation. Each signal is also individually controlled by the control unit 70.
Is input to A display unit such as a liquid crystal panel operated by an output from the control device 70 is provided on an operation panel unit which can be viewed by an operator sitting on a seat in the cab 11 so that the cutting height detection value of the ultrasonic sensor 20 can be displayed as a numerical value. is set up.

The control device 70 outputs a predetermined elevating command signal to the first driving circuit 77 and the second driving circuit 78 in accordance with a predetermined calculation result, and outputs a hydraulic pressure in accordance with an output from the first driving circuit 77. While the electromagnetic solenoids 80a and 80b of the hydraulic switching valve 80 in the circuit 79 are operated, the electromagnetic solenoid 50a of the electromagnetic proportional pressure reducing valve 50, which is an example of a high-speed response electromagnetic valve, is operated according to the output from the second drive circuit 78. Then, the single-acting hydraulic cylinder 9 for raising and lowering the pre-cutting device 4 is operated.

In the hydraulic circuit 79 shown in FIG. 7, a pair of left and right rolling control hydraulic cylinders for controlling the relative left and right vehicle heights of the single-acting lifting hydraulic cylinder 9 and the right and left traveling devices 3 and the traveling body 1 are provided. Pressure oil is also supplied to a hydraulic control valve 51 and the like (not shown). In this case, the hydraulic circuit 79
A relief valve 54 is inserted in the oil supply passage 53 from the hydraulic pump 52 to the hydraulic switching valve 49. A check valve 55 and a slow return check valve 56 are connected in the middle of the hydraulic pipe from the output port of the 4-port 3-position switching electromagnetic hydraulic switching valve 80 to the single-acting hydraulic cylinder 9. The hydraulic switching valve 80
The other output ports are configured to supply oil to the other hydraulic control valves 51 at the same time.

A return throttle pipe 57 connected between the check valve 55 of the hydraulic pipe and the slow return check valve 56 has a variable throttle valve 58 for lowering the piston rod of the single-acting hydraulic cylinder 9 and an emergency lowering valve 59. And are connected in parallel. The variable throttle valve 58 is a two-port two-position switching type valve.
The pilot port has one of the aforementioned high-speed response solenoid valves.
The output port of the electromagnetic proportional pressure reducing valve 50 is connected as an example.

The operation control of the hydraulic cylinder 9 for raising and lowering the pre-cutting device 4 is executed as follows. That is, when the hydraulic hydraulic pressure switching valve 80 is switched to extend the hydraulic cylinder 9 (when the pre-cutting device 4 is driven upward).
, The electromagnetic solenoid 80a is controlled by pulse width modulation (PW
M), the pilot pressure appropriately adjusted to the hydraulic pressure by the electromagnetic proportional pressure reducing valve 50 acts on the variable throttle valve 58, the degree of throttle of the variable throttle valve 58 is arbitrarily changed, and the return oil pipe 57 is connected to the oil tank. Drained to 60. In that case,
The operating speed of the hydraulic cylinder 9 is adjusted according to the degree of throttle of the variable throttle valve 58.

When the hydraulic cylinder 9 is reduced (when the pre-cutting device 4 is driven downward), the hydraulic switching valve 80 is set to neutral, and the electromagnetic proportional pressure reducing valve 50 is controlled in the same manner as described above by pulse width modulation control ( The operation is performed by a PWM (PWM) method, and the throttle opening of the variable throttle valve 58 is adjusted by adjusting the pilot pressure, whereby the operating speed of the hydraulic cylinder 9 is adjusted.

Next, the cutting height control will be described. When the automatic switch 75 for setting the automatic mode is turned on, the ultrasonic sensor 2 as a non-contact sensor is used.
The detected value of 0 is input to the control device 70 and the cutting height setting device 7
3, a comparison is made with a preset cutting height set value, and when the detection value of the ultrasonic sensor 20 is higher, the cutting pre-processing device 4 via the hydraulic pressure switching valve 80 and the electromagnetic proportional pressure reducing valve 50. Is moved downward, and when the detection value of the ultrasonic sensor 20 is lower, the mowing pre-processing device 4 is driven to rise, and is automatically adjusted so as to reach the set mowing height. In these cases, when the deviation between the setting value of the cutting height and the detection value of the ultrasonic sensor 20 is large, the hydraulic cylinder 9 is driven quickly by the continuous drive signal, and the lifting / lowering speed of the pre-cutting device 4 is increased. Is smaller, the drive speed of the hydraulic cylinder 9 is reduced by the pulse width modulation control (PWM) method, and the vertical movement speed of the pre-cutting device 4 is reduced, thereby enabling fine adjustment of the cutting height.

By the way, the field scene is not sufficiently scratched, or the field scene becomes uneven due to the application of fertilizers and chemicals, grooving work and the like. As shown in FIG. 8, when the combine enters the field over the ridges, the traveling body 1
The front of the traveling body 1 is pitched greatly in the front-rear direction such that the front of the traveling body 1 is tilted forward and downward, and then the pre-cutting device 4 on the front side of the traveling body 1 first touches the field scene to ground. I will. Since the ultrasonic sensor 20 as a non-contact type cutting height sensor is disposed behind the weeding body 10 and the detection result is apt to vary, the cutting height control delay occurs, or the unevenness portion is partially reduced. The ultrasonic sensor 20 detects a sudden change in the vertical distance between the ground and the ultrasonic sensor 20 due to a sudden change in the posture of the traveling body 1 in the front-rear direction.
If the lower end of the herd body 10 is brought very close to the field scene, the tip of the herb body 10 may be protruded into the convex portion of the field scene.

Accordingly, in the present invention, the ultrasonic sensor 2
When the cutting height control is performed by zero, a fluctuation amount relating to pitching (a pitching amount or a pitching fluctuation amount per unit time is measured from the detection result of the pitching sensor 92 mounted on the traveling machine 1 and the fluctuation amount is determined to be a predetermined value). When the value exceeds the value, the cutting pre-processing device 4 is controlled to move up and down in the direction opposite to the pitching direction of the traveling machine body 1, and this raising and lowering control is given priority over the raising and lowering control by the ultrasonic sensor 20.

The lifting control will be briefly described with reference to the flowchart shown in FIG. 9. Following the start of the control, the detection values of the ultrasonic sensor 20 and the pitching sensor 92 are extracted at regular time intervals (S1). Next, it is determined whether or not the fluctuation amount related to the pitching based on the detection result of the pitching sensor 92 is equal to or more than a predetermined value (including the case where the value detected by the pitching sensor 92 is equal to or more than a predetermined value) (S2).
If the value is equal to or more than the predetermined value (S2: yes), the control unit controls the raising and lowering of the pre-cutting device 4 in a direction opposite to the pitching direction (S3). For example, when the traveling body 1 is suddenly pitched forward and downward, the pre-cutting device 4 is raised and the pre-cutting device 4 is moved relatively upward with respect to the front end of the traveling body. Conversely, when pitching so that the front end of the traveling machine body 1 suddenly faces upward, the cutting pre-processing device 4 is moved downward. Such control is referred to as pitching-related elevation control. Next, it is determined whether a predetermined time has elapsed (S4), and if the predetermined time has elapsed (S4: yes)
s) The normal cutting height control is executed (S5). At the time of normal mowing and threshing work, it is considered that the sudden pitching phenomenon of the traveling body in the front-rear direction does not continue very much.
By executing the pitching-related control with a time limit as shown in 3, it is possible to quickly return to the normal cutting height control.

In the pitching-related elevation control,
The electromagnetic solenoid is continuously excited so as to raise and lower the hydraulic cylinder 9 at a high speed. Next, a description will be given of a mode of the elevation control of the pre-cutting device 4 in the manual mode.
The operation lever 76a of the manual switch 76 can be tilted back and forth and is urged to automatically return to the neutral position.
6a is downwardly moved at a predetermined elevating speed Vo (for example, an operating speed in a state in which the electromagnetic solenoid is continuously excited) while tilting forward, and is predetermined elevating speed Vo while tilting backward.
To continue rising.

In the manual mode, as a fine adjustment switching means for finely raising and lowering the raising and lowering speed of the pre-cutting device 4 at the fine speed V2 lower than the predetermined speed Vo, the ON / OFF of the foot switch 74 is used. As shown in FIG. 8, a step-up petal 87 projects upward from a floor plate below the left front side of the seat 11a. A pouring petal 88 for turning on / off the pouring clutch 48 is disposed so as to protrude from a floor plate below the round handle 89.

When the foot switch 74 is ON,
That is, assuming that the operator operates the fine adjustment switching means, when the depressed petal 87 is depressed, the mowing pre-processing device 4 is raised or lowered at the slow speed V2 only during the depression (the raising or lowering is performed manually. Switch 76
Corresponding to the raised position or the lowered position). The very low speed V2 is executed by operating the hydraulic cylinder 9 by the pulse width modulation control (PWM) method.

During a few hundred milliseconds after the manual switch 76 is turned on to the descending side, the direct drive in the descending direction by the solenoid valve 58 is prohibited, and the flow rate is controlled by the pulse width modulation control (PWM) method. Then, when the manual switch 76 remains ON on the descending side, the continuous descending drive is executed. Similarly, for several hundred milliseconds after the manual switch 76 is turned on to the ascending side, direct drive in the ascending direction by the solenoid valve 58 is prohibited, and pulse width modulation control (PWM) is performed.
When the manual switch 76 is kept ON on the ascending side after that, the fine ascending is executed by the flow control in the method, and the continuous ascending drive is executed.

[0035]

As described above, the cutting height control device in the combine according to the first aspect of the present invention is configured such that the cutting pretreatment device can be raised and lowered with respect to the front portion of the traveling machine body by the lifting drive means. The cutting height control device in the combine which is configured to operate the lifting / lowering driving means based on a detection signal of a non-contact type cutting height sensor for detecting a ground height of the cutting pre-processing device, A pitching sensor capable of measuring a variation in pitching of the traveling body in the front-rear direction, and when it is determined that the variation in pitching based on the detection result of the pitching sensor is equal to or greater than a predetermined value, the non-contact cutting height is determined. The lifting control based on the detection signal of the sensor is prioritized, and the operation of the lifting drive means is controlled in a direction opposite to the pitching direction of the traveling body. Are those that you configured.

Therefore, when the traveling body rapidly pitches up and down in the front-rear direction, such as when passing through a large uneven portion in a field or when entering a field over a ridge, the detection result of the non-contact type sensor is used. Since the response of the lifting control becomes impossible or the control delay occurs, the pitching sensor detects the pitching magnitude of the traveling body quickly and accurately, and uses the detection result of the pitching sensor to reverse the pitching direction. By raising and lowering the pre-cutting device in the direction, it is possible to reliably prevent the lower end of the pre-cutting device from colliding with the ground.

[Brief description of the drawings]

FIG. 1 is a side view of a combine.

FIG. 2 is a plan view of the combine.

FIG. 3 is a front view of the combine.

FIG. 4 is a side view showing a mounting position of a position sensor.

FIG. 5 is a plan view showing a mounting position of a position sensor.

FIG. 6 is a skeleton diagram of a power transmission system.

FIG. 7 is a functional block diagram of a hydraulic circuit and control means.

FIG. 8 is a view showing a state of a combine over a ridge.

FIG. 9 is a flowchart of the lifting control of the pre-cutting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running body 4 Cutting pre-processing device 9 Hydraulic cylinder 20 Ultrasonic sensor 70 Control device 92 Pitching sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Taiji Mizukura 1-32 Chaya-cho, Kita-ku, Osaka-shi Yanmar Agricultural Machinery Co., Ltd. Inside

Claims (1)

[Claims] A cutting pre-processing device is configured to be able to move up and down with respect to a front part of a traveling machine body by a lifting drive means, and a detection signal of a non-contact type cutting height sensor for detecting a ground height of the cutting pre-processing device. The cutting height control device in a combine which is configured to operate the lifting / lowering drive means according to the following: The traveling body is provided with a pitching sensor capable of measuring a variation amount of pitching of the traveling body in the front-rear direction. When it is determined that the fluctuation amount relating to the pitching based on the detection result is equal to or greater than a predetermined value, priority is given to the lifting / lowering control based on the detection signal of the non-contact type cutting height sensor, and the pitching direction of the traveling body is reversed. A cutting height control device in a combine, wherein the lifting drive means is controlled to operate in a direction.