JPH10331679A - Vehicular speed control device in working car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control vehicular speed of a combine by a hydraulic system. SOLUTION: This device transmits power from an engine 17 to a traveling part through a hydraulic system consisting of a hydraulic pump 33 capable of shift control and a hydraulic motor 34 and controls the pump 33 to hold constant vehicular speed by controlling to increase and decrease a discharge amount of pressure oil by operating a cam plate of the hydraulic pump 33 by a manual change-over valve 79 and a hydraulic servo cylinder 78 so as to hold vehicular speed corresponding to an operational position of a main shift lever in an automatic vehicular speed control mode. In the meantime, the cam plate of the hydraulic pump 33 is operated by detecting that a load factor of the engine becomes higher than a specified value by an electronic governor device, sending a speed reduction command signal to a solenoid 77a for speed reduction of a solenoid control valve 77 so as to reduce the vehicular speed by a specified ratio or specified quantity to holding vehicular speed, moving a position of a piston 78a of the hydraulic servo cylinder 78. When a load of the engine 17 returns to a proper value, it is controlled to return to the holding vehicular speed by taking a specified period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural machine such as a harvester such as a thresholder or a combine for harvesting rice, wheat, soybeans, etc. For controlling a vehicle speed in a working machine (working vehicle) for civil engineering, such as a motor scraper or a concrete mixer truck.

[0002]

2. Description of the Related Art In a harvester such as a thresholder or a combine equipped with a pre-cutting device in front of a traveling machine body equipped with a processing unit for threshing and the like, a gasoline engine or a diesel engine mounted on the traveling machine body is used. The power from the two engines is transmitted to a traveling drive unit, the above-mentioned mowing pre-processing device, and a work unit for threshing and the like, and a predetermined work is performed at each location.

[0003] In this case, since the vehicle travels at a low speed with a large traveling load when traveling in a wet field, the cutting speed is low and the load on the threshing unit is not very large. Conversely, when harvesting the rain-grained culm in the dry field, even if the running load is not so large, the load on the running section changes such that the load on the threshing section increases due to threshing of the rain-grained culm, It does not always link with the fluctuation of the load of the working unit.

Accordingly, as disclosed in Japanese Patent Application Laid-Open No. 2-2573, prior art, power from an engine is transmitted to a traveling section via hydraulic drive means capable of controlling gear shifting, while the hydraulic drive means In many cases, the power from the engine is transmitted to the working unit in parallel, and the shift operation between the traveling unit and the working unit is often performed in different systems. In Japanese Patent Publication No. 49-34494, a charge pump and a control valve are provided in a hydraulic circuit of an HST-type continuously variable transmission mechanism including a hydraulic pump and a hydraulic motor, and the control valve is operated in accordance with the load of the engine. By interlocking with the operating governor, the vehicle speed control means of the combine, which operates to change the inclination angle of the swash plate of the hydraulic pump and controls to run at the optimum vehicle speed according to the load of the work machine, It has been disclosed.

[0005]

However, in the above-mentioned vehicle speed control, the load is decelerated if the load becomes overloaded even if the load is slightly smaller than the load set value by the governor. However, since the vehicle speed is controlled so that the rotation speed of the handling cylinder of the combine is always constant, the hunting phenomenon tends to occur in the vehicle speed control.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle speed control device for a working machine which solves the above-mentioned problems and does not cause a hunting phenomenon in the vehicle speed control and is simple in control.

[0007]

According to a first aspect of the present invention, there is provided a vehicle speed control apparatus for a working machine, comprising: a hydraulic pump capable of controlling a speed of an engine mounted on the working machine; A vehicle speed control means for transmitting the load of the engine to a traveling unit via a hydraulic drive means comprising a motor, detecting the load of the engine by detecting a fuel supply amount of an electronic governor device or the like, and controlling the vehicle speed in a deceleration direction when overloaded. In the working machine provided, the swash plate of the hydraulic pump in the hydraulic drive means is operated to increase or decrease the discharge amount of the pressure oil in association with the operation of the main shift lever, and the vehicle speed control means includes: In the vehicle speed control mode, while controlling to maintain the vehicle speed corresponding to the operation position of the main shift lever, while providing hydraulic servo means for operating the swash plate of the hydraulic pump, The speed control means detects that the load factor of the engine has become a certain value or more, and sends a deceleration command signal to the hydraulic servo means to reduce the vehicle speed by a certain ratio or a certain amount with respect to the holding vehicle speed, When the load of the engine returns to an appropriate value, control is performed so that the vehicle speed returns to the holding vehicle speed in a predetermined time.

[0008]

As described above, the vehicle speed control means is:
In the vehicle speed control mode, while controlling to maintain the vehicle speed corresponding to the operation position of the main shift lever,
Hydraulic servo means for operating the swash plate of the hydraulic pump is provided, and the vehicle speed control means detects that the load factor of the engine has become equal to or more than a certain value, and detects a constant ratio or a constant value with respect to the holding vehicle speed. A deceleration command signal is sent to the hydraulic servo means to reduce the vehicle speed by an amount, and when the load of the engine returns to an appropriate value, control is performed so as to return to the holding vehicle speed. Hunting phenomenon does not occur in control.

Further, since the vehicle speed control is executed by the hydraulic servo means of the hydraulic system different from the hydraulic circuit for closing the hydraulic pump and the hydraulic motor, there is an effect that the reliability is high and the control is simple. Furthermore, since the vehicle speed is gradually increased after a predetermined time, the operator riding on the combine can safely operate the vehicle and the power transmission mechanism is not adversely affected.

[0010]

Next, an embodiment in which the present invention is applied to a combine serving as a harvester will be described. FIG. 1 is a side view of a traveling body 1 of a combine which is a traveling vehicle having a pair of left and right traveling crawlers 2a and 2b.
A threshing device 3 is mounted on the upper side, and a pre-cutting device 4 is mounted on a front portion of the threshing device 3 so as to be able to move up and down by a hydraulic cylinder (not shown). , A clipper-type reaper 5 on the lower surface side of the lower frame,
A grain stalk raising device 6 for six rows is arranged in the front, and a grain stalk transport device is arranged between the grain stalk raising device 6 and the feed chain 7 in the threshing device 3, and a lower front portion of the grain stalk raising device 6 is provided in front of the grain stem raising device 6. The weeds 8 protrude.

The handling cylinder in the handling room of the threshing device 3 is arranged so that the axis thereof is along the traveling direction of the traveling machine body 1, and the root portion is held by the feed chain 7 arranged on one side of the handling room. The spike of the grain culm to be conveyed is threshed by the handling cylinder 3a in the handling room. In the lower part of the handling room, a rocking sorter using a catching net and a sheave and a wind sorter using the wind of Karino Juan are installed. On the side of the threshing device 3, a paddy tank 9 for storing threshed grains is mounted. ing. Further, a grain discharging auger 10 protruding from the rear portion of the traveling machine 1 is configured to be horizontally rotatable and vertically rotatable for discharging threshed grains from the paddy tank 9 to a carrier (not shown) outside the machine. ing. As shown in FIG. 2, a driver's cab 11 provided on one side of the front of the traveling body 1 has a round handle 12 for steering the traveling body 1, a main speed change lever 13 for changing the speed, and a subtransmission. Lever 1
4, and switches (not shown) for various operations are arranged.

The left and right traveling crawlers 2a and 2b are respectively connected to left and right output shafts 21 of a power transmission device 20 shown in FIG.
a, crawler belts 24, 24 wound around starting wheels 22, 22 driven to rotate by the power output from a, 21 b, and guide wheels 23, 23 urged rearward toward the rear end side of the traveling body 1.
Each of the crawler belts 24 includes a lower rolling wheel 25 for supporting a lower inner peripheral surface.

Next, a description will be given of the structure of a power transmission device 20 comprising a two-pump two-motor type HST type continuously variable transmission mechanism. In the embodiment shown in FIG. 3, a differential gear mechanism including a pair of left and right planetary gear mechanisms 31, 31 described below, and a traveling hydraulic pressure including a first hydraulic pump 33 and a first hydraulic motor 34 are provided in a transmission case 30. A swing type hydraulic drive unit including a second hydraulic pump 36 and a second hydraulic motor 37, a power transmission gear mechanism, and the like are provided. In addition,
The rotational force from the engine 17 mounted on the traveling body 1 is transmitted to both hydraulic pumps 33 and 36 outside the transmission case 30 via the chain sprocket and the endless chain 60.
, And hydraulic power is transmitted to the hydraulic motors 34 and 37 via hydraulic paths in the transmission case 61.

The pair of left and right planetary gear mechanisms 31, 31 are symmetrical in the left-right direction, and a plurality (three in the embodiment) are provided on the same radius.
A pair of left and right bracelets 38, 38 on which the planetary gears 39, 39, 39 are rotatably supported, respectively.
It is arranged so as to be opposed to each other on the coaxial line within 0 as appropriate. Sun gear 4 meshing with each of the planetary gears 39
The left and right ends of the sun shaft 41 to which 0 and 40 are fixed are
It is rotatably supported by a bearing located at the center of rotation of the inner side of each of the insides 8 and 38. The ring gear 42 having the inner teeth on the inner peripheral surface and the outer teeth on the outer peripheral surface is arranged concentrically with the sun shaft 41 so that the inner teeth mesh with the three planetary gears 39, 39, 39, respectively. And this ring gear 4
2 is rotatably supported via a bearing on the sun shaft 41 or on a central shaft 43 projecting outward from the outer surface of the wristband 38.

The direction and amount of discharge of the pressure oil to the first hydraulic motor 34 by changing and adjusting the inclination angle of the rotary swash plate of the variable displacement type first hydraulic pump 33 in the traveling hydraulic drive means. , The rotation direction and the number of rotations of the output shaft of the first hydraulic motor 34 can be adjusted.
The rotational power from the input shaft of the first hydraulic motor 34 is transmitted to the auxiliary transmission mechanism 50 constituted by a conventionally known gear mechanism via gears 44, 45, 46, 47.
The light is transmitted to a center gear 49 fixed to the sun shaft 41 via the output gear 48.

A PT for transmitting a rotational force to a working machine or the like through a gear mechanism 51 associated with a shaft 44a of the gear 44.
Output to the O-axis 52. In this case, a clutch means 52a is provided in the middle of the PTO shaft 52. Accordingly, the rotational power from the traveling hydraulic drive means is transmitted to the center gear 49 via the transmission gear mechanism and the auxiliary transmission mechanism 50, and then the pair of left and right planetary gear mechanisms 31, 31.
The transmission gear 53 fixed to the central shaft 43 of the left arm ring 38 meshes with the transmission gear 54 fixed to the left output shaft 21a, and is output. Similarly, the transmission gear 53 fixed to the central shaft 43 of the right wrist ring 38 meshes with the transmission gear 54 fixed to the right output shaft 21b and outputs.

On the other hand, by changing and adjusting the inclination angle of the rotary swash plate of the variable displacement type second hydraulic pump 36 in the turning hydraulic drive means, the discharge direction and pressure of the pressure oil to the second hydraulic motor 37 are changed. By changing the amount, the rotation direction and the number of rotations of the output shaft of the second hydraulic motor 37 can be adjusted. The rotational power from the second hydraulic motor 37 is transmitted to a pair of transmission gears 56 and 57 via a gear mechanism 55. Next, as shown in FIG.
The transmission gear 56 directly meshes with the transmission gear 56, the transmission gear 57 on the right side meshes with the reverse rotation gear 59 mounted on the reverse rotation shaft 58, and the rotation reduction gear 59 and the external teeth of the ring gear 42 on the right side mesh with each other.

Therefore, when the left ring gear 42 rotates reversely at a predetermined rotation speed by the forward rotation of the second hydraulic motor 37, the right ring gear 42 rotates forward at the same rotation speed as described above. With this configuration, for example, if the turning hydraulic drive unit is stopped, the rotation of the left and right ring gears 42, 42 is in a fixed state stopped. When the traveling hydraulic drive unit is driven in this state, the rotational force from the first hydraulic motor 34 is applied to the center gear 49 of the sun shaft 41.
Is input to the sun gear 40,
It is transmitted to the left and right output shafts 21a and 21b via the planetary gear 39 and the arm gear 38 of the planetary gear mechanism on both the left and right sides at the same rotational speed in the same direction in the same direction. , Can go straight. Therefore, when only the traveling hydraulic drive means is driven in the forward direction, the traveling body 1 advances straight ahead, and when driven in the reverse direction, it moves straight forward and backward.

On the other hand, when the traveling hydraulic drive means is stopped, the sun shaft 41 and the left and right sun gears 4 are stopped.
0 and 40 are fixed. In this case, it is preferable to operate a brake means (not shown). In this state, when the turning hydraulic drive means (second hydraulic motor 37) is driven, for example, in forward rotation, the planetary gear mechanism including the left planetary gear 39 and the arm gear 38 rotates in the reverse direction, while the right planetary gear rotates. Gear 39,
The planetary gear mechanism including the arm gear 38 rotates forward. Therefore, the left traveling crawler 2a moves backward while the right traveling crawler 2b moves forward, so that the traveling body 1 spins to the left at that location.

Similarly, the turning hydraulic drive means (second
When the hydraulic motor 37) is driven in reverse rotation, the left planetary gear mechanism 31 rotates forward, the right planetary gear mechanism 31 rotates in reverse, and the left traveling crawler 2a moves forward while the right traveling crawler 2b moves backward. Therefore, the traveling body 1 spins right on the spot. When the turning hydraulic drive unit is driven while the traveling hydraulic drive unit is driven, it is possible to turn right or left with a turning radius larger than the spin turn turning radius during forward or backward movement. The turning radius is determined according to the speed of the left and right traveling crawlers 2a and 2b.

In each of the above cases, the sub-transmission lever 14 is moved and set to a road running mode, an agricultural work mode, an ultra low speed mode, or the like. In this state, if the main shift lever 13 is set to the upright posture, the neutral position (N position) is reached, and the main shift lever 1
When the vehicle 3 is tilted forward, the traveling vehicle moves forward, and when the forward lean angle is large, the forward speed increases. Conversely, when the main transmission lever 13 is tilted backward, the traveling vehicle moves backward, and when the inclination angle is large thereafter, the speed of the backward movement increases. By turning the handle 12 right or left, the traveling vehicle can turn in a predetermined direction.

FIG. 5 shows a hydraulic circuit 70 in the traveling hydraulic drive means, in which a charge pump 71 is separately driven by a drive shaft from the engine 17, and the hydraulic oil therefrom is used as a functional hydraulic servo means to be described later. Send to 72. A pair of hydraulic adjustments as a brake valve for absorbing inertia acting on the hydraulic motor 34 at a downstream side in a hydraulic passage formed of a closed circuit from the first hydraulic pump 33 for traveling to the first hydraulic motor 34. The valve 73 is connected. As shown, each hydraulic pressure adjusting valve 73 includes a pair of a check valve and a relief valve. A check valve and a throttle valve are provided upstream of the pair of hydraulic adjustment valves 73, and the main hydraulic circuit 7
0 (closed circuit) is connected to a pair of pressure oil adjusting valves 74 for switching the pressure oil little by little.
The pressure oil passage 76 from 1 is connected between the pair of pressure oil adjustment valves 74, 74, and is connected to a relief valve 75 for releasing the pressure oil to the drain.

The extension of the pressure oil passage 76 includes
The electromagnetic control valve 77 at the port 3 position and the manual switching valve 79 are connected in parallel. The manual switching valve 79 is connected to the main transmission lever 13 via an interlocking mechanism (not shown),
On the basis of the operation position of the main transmission lever 13, the manual switching valve 79
The piston 78a of the cutting hydraulic servo cylinder 78 is moved in accordance with the switching operation, and the hydraulic pressure is changed via the passage 80 by operating the swash plate of the first hydraulic pump 33 in accordance with this movement. Part (cylinder)
The inclination angle of the swash plate is changed so that the vehicle can be maintained at a vehicle speed corresponding to the set position of the main transmission lever. On the other hand, the output port from the electromagnetic control valve 77 is connected to the output port of the manual switching valve 79 from the hydraulic servo cylinder 78.
Connect in parallel to the passage to. The electromagnetic control valve 77 sends a predetermined command signal (a signal corresponding to the degree of engine load) from a computer-type controller described later to the deceleration solenoid 77a or the speed-up solenoid 77b.
By moving the piston 78a in the hydraulic servo cylinder 78 regardless of the operation of the manual switching valve 79,
As described above, the vehicle speed can be controlled to increase or decrease by changing the inclination angle of the swash plate of the first hydraulic pump 33.

Numeral 81 shown in FIG. 6 is a control device as control means for executing vehicle speed control of the traveling machine body and control of fuel supply to the engine, and at least when the load factor of the engine exceeds a certain value. The inclination angle of the swash plate of the first hydraulic pump 33 is changed and adjusted via the hydraulic servo cylinder 78 to adjust the amount of hydraulic oil discharged, and finally, the rotational speed of the first hydraulic motor 34, As a result, the vehicle speed can be controlled to decelerate. The control device 81 is a central processing unit (CPU) that is electronically controlled by a microcomputer or the like.
A read-only memory (ROM) for storing in advance a control program and an initial value necessary for arithmetic processing by the central processing unit, an arithmetic map necessary for a conversion operation to be described later, and the like;
It comprises a read / write memory (RAM) for temporarily storing various input data used for arithmetic processing, an input / output interface, and the like, and is connected to the following input / output units.

That is, the vehicle speed control mode is turned ON / OFF.
Vehicle speed automatic switch 82, a vehicle speed sensor 83 in a traveling section, an engine speed sensor 84 such as a pulse encoder provided on an output shaft of the engine 17 or an output shaft of a transmission case for detecting the speed of the engine 17. A load sensor 85 for detecting a fuel supply amount in the fuel supply device as a load sensor capable of detecting a load state of the engine, and an ON / OF of a cutting clutch device for power-connecting the cutting pre-processing device 4 by turning the cutting pre-processing device 4 ON.
An F-switch 86, an ON / OFF switch 87 of a threshing clutch device for power-connecting the threshing unit 3 by ON, a lever position sensor 88 for detecting an operation position of the main transmission lever 13, and the like are connected to input ports of the control device 81. Connecting.

The output port of the controller 81 has a solenoid 77a for deceleration of the electromagnetic control valve 77 for changing and adjusting the angle of the swash plate of the first hydraulic pump 33 for traveling of the traveling crawlers 2a and 2b. Solenoid 77b for the right turn solenoid and the left turn solenoid 89b of the electromagnetic control valve for changing and adjusting the angle of the swash plate of the second hydraulic pump 36 for turning, and a display indicating that the automatic operation is being performed. The control device 2 includes a lamp 90 and a display device 91 capable of displaying the load state of the engine with characters such as liquid crystal or the like and displaying the load state such as overload of the working unit with a warning display lamp.
8 output ports.

Although not shown, an electromagnetic solenoid of a cutting clutch device, an electromagnetic solenoid of an auger clutch device of a discharge auger 10 for discharging grain from a paddy tank, an electromagnetic solenoid of a traveling clutch device, an electromagnetic solenoid of a threshing clutch device, and the like. Are also connected to the output ports of the control device 28, respectively. The fuel supply device is a fuel injection pump installed at a location such as a throttle valve or an air flow meter of a carburetor of an intake system when the engine 17 is a gasoline engine, and is directly injected into a cylinder when the engine 17 is a diesel engine. In the case of the throttle valve, an actuator such as a solenoid that rotates a valve operating shaft for operating the opening / closing degree of the throttle valve is used as a fuel injection pump. In the case of an injection pump, it is an actuator such as a step motor which is mounted on a rack for adjusting the position of a plunger for adjusting the injection amount and moves the same.

The load sensor 85 may be a potentiometer for detecting the rotation angle of the throttle valve, or a linear differential transformer type displacement sensor which can be mounted in parallel with the rack to detect the moving position of the rack. Next, a mode of vehicle speed control in the vehicle speed control mode will be described. When the vehicle speed automatic switch 82 is pressed and turned on to rotate the main speed change lever 13 forward from the neutral position (stop position), the vehicle can travel forward at the vehicle speed Vs according to the rotation angle. When the main transmission lever 13 is rotated backward from the neutral position, the vehicle travels backward according to the angle. The traveling speed of the combine is maintained at a speed corresponding to the set position of the main transmission lever 13.

Then, as shown in FIG. 7 (a), when the engine load becomes 95% or more of the rated value, the deceleration command signal is turned from OFF to ON, and conversely, when the engine load becomes 85% or less of the rated value, it is turned on. A signal is issued from the control device 81 so as to switch to OFF. In the state where the deceleration command signal is ON, a continuous drive signal or a pulse signal for pulse width modulation control is output to the deceleration solenoid 77a of the electromagnetic control valve 77 regardless of the rotational position of the main transmission lever 13. Then, the speed is reduced by a fixed rate of the holding speed Vs (see FIG. 7B).

Next, when the engine load returns to an appropriate value (85% or less of the rated value in the embodiment), the deceleration command signal switches from ON to OFF, and as shown in FIG. The speed returns to the speed Vs. In this case, the speed is not increased rapidly, but is gradually increased after a predetermined time t (for example, several seconds). When the vehicle speed is gradually increased in this manner, the operator riding on the combine can safely operate the vehicle and does not adversely affect the power transmission mechanism.

It is needless to say that the present invention can be applied to not only the combine but also other types of agricultural work machines and civil engineering work machines.

[Brief description of the drawings]

FIG. 1 is a side view of a combine.

FIG. 2 is a front view of the combine.

FIG. 3 is a skeleton diagram of a two-pump two-motor type hydraulic stepless speed change mechanism.

FIG. 4 is a partial sectional view of a pair of planetary gear mechanism units.

FIG. 5 is a hydraulic circuit diagram.

FIG. 6 is a functional block diagram of a vehicle speed control means.

FIG. 7A shows ON / OFF of an engine load and a deceleration command signal.
FIG. 4B is a time chart showing a change in vehicle speed due to ON / OFF of a deceleration command signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling body 2a, 2b Traveling device 3 Threshing device 4 Harvesting pretreatment device 17 Engine 33 First (for traveling) hydraulic pump 34 First (for traveling) hydraulic motor 70 Hydraulic circuit 71 Charge pump 77 Electromagnetic control valve 78 Servo hydraulic pressure Cylinder 79 Manual switching valve 80 Passage 81 Control device

Claims (1)

[Claims] An engine mounted on a work machine is transmitted to a traveling unit via a hydraulic drive unit including a hydraulic pump and a hydraulic motor capable of speed change control, and the engine load is transmitted to a fuel such as an electronic governor device. In a working machine comprising a vehicle speed control means for detecting the supply amount and detecting the vehicle speed in the deceleration direction when overloaded, the swash plate of the hydraulic pump in the hydraulic drive means is associated with the operation of the main transmission lever. It is configured to operate to increase or decrease the discharge amount of pressure oil,
In the vehicle speed control mode, the vehicle speed control means includes:
Hydraulic servo means for operating the swash plate of the hydraulic pump is provided while controlling to maintain the vehicle speed corresponding to the operation position of the main shift lever, and the vehicle speed control means sets the load ratio of the engine to a constant value. Detecting that it became above,
A deceleration command signal is sent to the hydraulic servo means to reduce the vehicle speed by a fixed ratio or a fixed amount with respect to the holding vehicle speed, and when the load of the engine returns to an appropriate value, it takes a predetermined time to return to the holding vehicle speed. Speed control device in a working machine, characterized in that the vehicle speed is controlled as follows.