JPH10339181A - Car speed controller in work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a controllable application range by setting car speed control of a combine to be changeable between two types. SOLUTION: Power from an engine 17 is transmitted through a hydraulic system comprising a speed-change controllable hydraulic pump 33 and a hydraulic motor 34 to a running part, a swash plate of the hydraulic pump 33 is operated by a manual selector valve 79 at a hydraulic servo means 72 in a speed reduction control mode to hold car speed corresponding to the operation position of a main speed change lever for controlling discharge quantity of pressure oil to keep a constant car speed, and a load rate of the engine 17 becoming a specified value or more is detected by an electronic governor to actuate an electromagnetic control valve 77 to decrease the car speed for a specified quantity from the held car speed, when a position of a piston is moved to operate the swash plate in the hydraulic pump 33. As load on the engine 17 returns to a correct value, the car seed is controlled to return to the held car speed in a specified time. In a car speed control mode, speed is controlled to be decreased when the engine load rate exceeds a specified value, and increased when it is a specified value or less.

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.

Also, depending on the conditions of the workplace, there is a problem that the work is not stabilized only by the vehicle speed control. An object of the present invention is to provide a vehicle speed control device for a working machine that solves the above-described problem and does not cause a hunting phenomenon in vehicle speed control and can increase the applicable range of control. is there.

[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 work machine having vehicle speed control means for transmitting to a traveling unit via a hydraulic drive means including a motor, detecting an engine load by detecting a fuel supply amount of an electronic governor device or the like, and controlling a vehicle speed to increase or decrease. Wherein the swash plate of the hydraulic pump in the hydraulic drive means is operated to increase or decrease the discharge amount of pressurized oil in association with the operation of the main transmission lever, and the vehicle speed control means comprises a vehicle speed control mode and a deceleration. In the vehicle speed control mode, control is performed such that the engine speed decreases when the engine load factor exceeds a certain value, and increases when the engine load factor is less than the certain value. Detecting that the load factor of the engine has exceeded a predetermined value, the vehicle speed is reduced by a predetermined ratio or a predetermined amount with respect to a holding vehicle speed corresponding to the operation position of the main shift lever, and the engine speed is reduced. When the load returns to the appropriate value, control is performed such 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 deceleration control mode, while controlling to maintain the vehicle speed corresponding to the operating position of the main shift lever, while detecting that the load factor of the engine has become a certain value or more, the vehicle speed with respect to the holding vehicle speed When the vehicle speed is reduced by a certain ratio or a certain amount and the load of the engine returns to an appropriate value,
Since control is performed so as to return to the holding vehicle speed, no hunting phenomenon occurs in the conventional vehicle speed control.

Further, since the vehicle speed is gradually increased after a predetermined period of time, the operator on the working machine can safely operate the vehicle, and the vehicle speed (work speed) can be restored.
Since the speed does not exceed the speed corresponding to the position of the main shift lever set in advance, the vehicle speed does not abnormally increase and safety can be ensured. On the other hand, in the vehicle speed control mode, the engine speed is maintained at the rated speed by decelerating when the load factor of the engine exceeds a certain value during work and increasing the speed when the load factor of the engine is less than the certain value. This is a control for properly maintaining the engine load while the vehicle speed is being controlled. By executing this vehicle speed control mode, the work is stabilized.

[0010] By selectively switching between the vehicle speed control mode and the deceleration control mode, under the working conditions, for example, the vehicle speed control alone, when the lodging grain culm is harvested and threshed, the vehicle speed exceeds the ability of the reaping section to cause the grain culm. When trouble occurs early, or when field conditions and crop conditions are not constant, hunting tends to occur due to vehicle speed control, and the riding comfort of the onboard operator deteriorates. When the mode is switched to the control mode, the speed does not exceed the speed corresponding to the position of the main shift lever set in advance, so that there is an effect that occurrence of trouble and occurrence of hunting can be prevented. In addition, when the field condition and the crop condition are good, the mode can be switched to the vehicle speed control mode, and the work can be streamlined.

As described above, there is an effect that the range of control can be expanded by switching the mode.

[0012]

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 disposed so that the axis thereof is along the traveling direction of the traveling machine body 1, and the root 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. The rotational force from the engine 17 mounted on the traveling body 1 is transmitted to the input shaft 33a of both hydraulic pumps 33 and 36 outside the transmission case 30 via the chain sprocket and the endless chain 60, or the belt and the pulley. Then, each hydraulic motor 3 is transmitted through a hydraulic path in the transmission case 61.
4 and 37 to transmit hydraulic power. The common shaft 33a
A charge pump 71 for supplying pressure oil to a hydraulic servo means to be described later is attached to one end of the motor (see FIG. 3,
(See FIG. 5).

As shown in FIGS. 3 and 4, the pair of left and right planetary gear mechanisms 31, 31 are bilaterally symmetric, and a plurality of (three in the embodiment) planetary gears 39, 39, 3 are arranged on the same radius.
A pair of left and right bracelets 3 each rotatably supported on a shaft 9
8, 38 are arranged facing each other on the coaxial line in the transmission case 30 as appropriate. The left and right ends of a sun shaft 41, to which sun gears 40, 40 meshing with the respective planetary gears 39 are fixed, are rotatably supported by bearings located at the center of rotation inside the two arm rings 38, 38. .
Ring gear 42 having inner teeth on the inner peripheral surface and outer teeth on the outer peripheral surface
Is arranged concentrically with the sun shaft 41 such that its inner teeth mesh with the three planetary gears 39, 39, 39, respectively. The ring gear 42 is provided on the sun shaft 41 or on the arm ring 38. It is rotatably supported via a bearing on a central shaft 43 projecting outward from the outer side surface.

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 discharge direction and discharge amount of the pressure oil to the first hydraulic motor 34 are changed. , 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 a subtransmission mechanism 50 constituted by a conventionally well-known gear mechanism via gears 44, 45, 46, 47, and an output gear 48 thereof. Through the center gear 49 fixed to the sun shaft 41.

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 in reverse 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 sun gears 4 on the left and right sides 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 the road running mode, the agricultural work mode, the super low speed mode, and 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. 7 shows a hydraulic circuit 70 in a first embodiment of vehicle speed control which can be switched between vehicle speed control and deceleration control in the traveling hydraulic drive means. , And sends the pressure oil therefrom to the hydraulic servo means 72 described later. In a hydraulic passage having a closed circuit from the first hydraulic pump 33 for traveling to the first hydraulic motor 34, a pair of brake valves as a brake valve for absorbing inertia acting on the hydraulic motor 34 in a downstream bypass passage. The hydraulic adjustment valve 73 is connected. As shown, each hydraulic pressure adjusting valve 73 includes a pair of a check valve and a relief valve. In the bypass passage upstream of the pair of hydraulic pressure adjusting valves 73, a check valve and a throttle valve are provided, and a pair of pressure oil adjustments for changing the pressure oil of the main hydraulic circuit 70 (closed circuit) little by little. Valves 74, 74
Is connected to the pressure oil passage 7 from the charge pump 71.
6 is connected between the pair of pressure oil regulating valves 74, 74, and is connected to a relief valve 75 for releasing the pressure oil to the drain.

The hydraulic servo means 72 provided at the extension of the pressure oil passage 76 moves the piston 100 linearly (in the embodiment, up and down) so that the first hydraulic pump 33 of the cradle type is moved. The vehicle speed is changed by changing the inclination angle of a swash plate (not shown). The electromagnetic control valve 77 at a 4-port 3-position for automatic vehicle speed control, and a manual switching valve 79 ( Spool 10 described later
1 may be moved relative to the piston 100). The manual switching valve 79 is connected to the main transmission lever 13 via an interlocking mechanism (not shown), and can switch the manual switching valve 79 based on the operation position of the main transmission lever 13. Based on the hydraulic servo means 72
, The inclination angle of the swash plate of the swash plate of the first hydraulic pump 33 is changed via the interlocking mechanism 80 in accordance with this movement, so that the vehicle speed corresponding to the set position of the main transmission lever 13 It is configured to be able to hold. On the other hand, the output port from the electromagnetic control valve 77 is connected in parallel to the passage from the output port of the manual switching valve 79 to the piston 100. The electromagnetic control valve 77 transmits a predetermined command signal (a signal corresponding to the degree of the engine load) from a computer-type controller described later to the deceleration solenoid 7.
7a or the speed increasing solenoid 77b, and only when the manual switching valve 79 is in the forward position, the piston 100 in the hydraulic servo means 72 is moved to tilt the swash plate of the first hydraulic pump 33 as described above. Change the angle,
The vehicle speed can be controlled to increase or decrease. Note that when the main transmission lever 13 and thus the manual switching valve 79 are at the neutral position and the retreat position, no command signal for increasing / decelerating the electromagnetic control valve 77 is issued (prohibited).

Next, the piston 100 and the spool 1 as the hydraulic servo means 72 will be described with reference to FIGS.
The configuration of 01 and the manual switching valve 79 will be described. FIG.
5 shows a plan view (partially imaginary line) of a power transmission device 20 composed of a two-pump two-motor type HST-type stepless speed change mechanism. A first hydraulic pump 33 for traveling is shown on the right side of FIG. The second hydraulic pump 36 is disposed so as to be driven by the input shaft 33a.
4 is arranged. The second hydraulic motor 37 for turning is disposed below the second hydraulic pump 36. First
Below the hydraulic pump 33, the same case block 110 is provided.
Inside the vehicle speed piston 100 as hydraulic servo means 72
And a spool 101 slidably fitted in the inner diameter portion of the vehicle speed piston 100.

Case block 110 of power transmission device 20
The pivot shaft 104 is rotatably fitted to the inner diameter of a boss 103 protruding from the outer surface side (the lower side in FIG. 5) of the pivot shaft 10.
4 is a nut 10
8, a neutral holding roller 106 a that is in contact with a neutral holding cam surface 105 a formed on the distal end surface of the travel stopper rod 105 is rotatably provided at the distal end of the neutral holding arm 106. The neutral holding arm 106 is rotatably supported by a support shaft 106 b projecting from the case block 110, and the neutral holding roller 106 a is constantly pressed against the neutral holding cam surface 105 a by the urging force of the urging spring 107. (See FIGS. 6 and 8).

A stopper plate 111 and a main transmission lever 13 are mounted on a cylindrical shaft 109 rotatably fitted on the boss 103.
And an operation arm 10 that rotates through an interlocking mechanism (not shown)
2 are fixedly connected to each other, and both ends of a torsion spring 112 for shock absorption fitted on the cylindrical shaft 109 are locked to the traveling stopper rod 105. The travel stopper rod 105
The engaging portion 105b provided at the other end of the arm and the engaging notch portion 111a of the stopper plate 111 engage with each other to
02 is restricted from rotating beyond a predetermined angle.

A pin 114 projecting from the free end of a crank arm 113 fixed to the inner end of the pivot 104 is
The lower groove 115 of the spool 101 is engaged. Therefore, the free end side of the crank arm 113 is rotated according to the rotation angle of the operation arm 102, and the spool 10
1 is configured to be able to move up and down (axial direction) relative to the inner diameter portion 100c of the vehicle speed piston 100. Thus, a manual switching valve 79 is configured.

FIG. 11A is a longitudinal sectional view of the piston 100, FIG. 11B is a view taken along the line XIb-XIb in FIG. 11A, FIG. 11C is a right side view, and FIG. ) Is FIG.
11C is a right end view, and FIG. 11E is XIe of FIG.
-XIe line arrow view, FIG. 11 (f) is XIf- of FIG. 11 (e).
It is a sectional view taken along the line XIf. As can be understood from these figures, the spool 1 is provided on the inner diameter portion 100c of the piston 100.
01 has an inner diameter portion 100a movable along an axis,
An insertion hole 100b into which the pin 114 can be loosely inserted is formed on one side surface of the notch formed in the middle of the outer periphery. A pressure oil hole 117 for supplying pressure oil from the charge pump 71 is formed on one side peripheral surface of the cylinder 116 formed on the case block 110. A long pump port 118 is formed in a recess, and a drilled oil passage 118a is formed from the pump port 118 toward the inner diameter portion 100c of the piston 100. In addition, in the inner diameter portion 100c of the piston 100,
A first port 119 and a second port 120 are formed at a position sandwiching the portion of the drilled oil passage 118a in the axial direction (see FIGS. 11A and 11E). Two oil passages 121 and 122 are formed outside the inner diameter portion 100c of the piston 100 along the axial direction and open to each end surface of the piston 100. The oil passage 121 is provided with a first port 119 and The other oil passage 122 is formed so as to communicate with the first end chamber 123 of the cylinder 116, and is connected to the second port 12.
0 and the second end chamber 124 of the cylinder 116 (see FIGS. 8 and 11A).

FIG. 12 (a) is a longitudinal sectional view of the spool 101, and FIG. 12 (b) is a side view of the outer periphery of the spool 101. An inner diameter passage 125 is provided, and the outer peripheral surface of the spool 101 is provided with the lower concave groove 115.
The first outer peripheral oil passage 126, the second outer peripheral oil passage 127, and the third outer peripheral oil passage 128 are formed at predetermined intervals above the position of the first outer peripheral oil passage 126, the third outer peripheral oil passage 126, and the third outer peripheral oil passage. Discharge passages 129 and 130 communicating with the inner diameter passage 125 are formed in the oil passage 128, respectively.

Further, rectangular parallel notches 131 and 132 having a predetermined dimension in the axial direction are formed in a land between the first outer peripheral oil passage 126 and the second outer peripheral oil passage 127, and the second outer peripheral oil passage 127 is formed. A land portion between the oil passage 127 and the third outer peripheral oil passage 128 has a rectangular parallel notch 13 having a predetermined dimension in the axial direction.
3 and 134 are formed (see FIG. 12B). The parallel notches 131 and 132 overlap the first inner diameter passages 119 of the piston 100 which have moved upward or downward relative to the spool 101 by operating the electromagnetic control valve 77 or the main transmission lever 13, respectively. obtain. The parallel notches 133 and 134 may each overlap the second inner diameter passage 120 in the piston 100 that has also moved up or down relative to the spool 101.

Therefore, the spool 101 and the piston 100
Relative to the third direction of the spool 101.
When the outer peripheral passage 128 (and the parallel notch 134) communicates with the second port 120 of the piston 100, the piston 10
0 and the inner diameter passage 12 of the spool 101
5 communicates. Similarly, the first outer peripheral passage 126 (and the parallel notch 131) of the spool 101 is
When the first port 119 communicates with the first port 119, the oil passage 121 of the piste 100 communicates with the inner diameter passage 125 of the spool 101.

The vertically moving piston 100
A connecting pin 136 as an interlocking mechanism 80 engaged with the outer peripheral recess 135 of the cradle is connected to a swash plate (not shown) of the cradle-type first hydraulic pump 33, and the swash plate is inclined according to the movement of the piston 100. The swash plate is rotated to change the angle, and the vehicle speed is controlled accordingly. FIG. 8 shows the deceleration solenoid 77a and the speed increasing solenoid 7 of the electromagnetic control valve 77.
This indicates a state in which no command signal is input to 7b, and the pressure oil from the charge pump 71 does not act on either the first end chamber 123 or the second end chamber 124 of the cylinder 116.

On the other hand, when the main shift lever 13 is located at the neutral position, the operation arm 102 and the neutral holding arm 106
The neutral holding cam surface 105 of the traveling stopper rod 105 via
While the neutral holding roller 106a is located at the neutral position a, the spool 101 is moved to the piston 100 by the pin 114 at the tip thereof and the lower groove 115 via the stopper rod 105, the pivot 104 and the crank arm 113. To stop at a predetermined position. In this state, the pressure oil from the charge pump 71 flows through the pressure oil hole 117 into the piston 100.
Although supplied to the pump port 118 on the outer peripheral surface, the spool 101 is in the neutral position, and only the pressure oil enters the land between the first outer peripheral oil passage 126 and the second outer peripheral oil passage 127 in the spool 101, Other land part is piston 100
Port 119 and second port 120 on the inner circumference of
Therefore, the hydraulic pressure is cut, so that the piston 100 does not move up and down. Therefore, the combine stops moving forward and backward.

When the electromagnetic control valve 77 is OFF,
When the main transmission lever 13 is turned forward from the neutral position, the control for moving forward at a speed corresponding to the turning angle includes:
The operation arm 120 rotates in a predetermined direction through an interlocking mechanism that interlocks with the movement of the main transmission lever 13, and this movement is performed by moving the crank arm 113 in a predetermined direction through the travel stopper rod 105 and the rotation pivot 104. Rotate by an angle.
Since the pin 114 at the tip of the crank arm 113 is fitted in the lower groove 115 of the spool 101, the spool 101 moves by a predetermined amount to the upper or lower position. Then, for example, the spool 101 moves relatively upward with respect to the piston 100, and the second outer peripheral oil passage 127
When the pressure oil comes to a position communicating with the second port 120 at 0, pressure oil from the charge pump 71 is supplied to the pressure oil hole 117 →
It is sent to the second end chamber 124 at the lower end side of the piston 100 via the pump port 118 → the second outer oil passage 127 → the second port 120 → the oil passage 122, and moves the piston 100 upward. The swash plate of the first hydraulic pump 33 is rotated through a predetermined angle via the
The pressure oil is sent so that 4 is driven to rotate at a predetermined speed. The return oil from the first end chamber 123 is supplied to the oil passage 1
21 → first port 119 → first outer peripheral passage 126 → discharge passage 129 → return to the drain via inner diameter passage 125.

Conversely, when the main speed change lever 13 is rotated backward from the neutral position, the spool 101 moves downward to control the speed to retreat at a speed corresponding to the rotation angle, and the second shift lever 13 moves downward. When the outer peripheral oil passage 127 comes to a position communicating with the first port 119 of the piston 110, the pressure oil from the charge pump 71 is discharged from the pressure oil hole 117 → the pump port 118 → the second outer peripheral oil passage 127 → the first port 1
19 → the second hydraulic motor 34 is sent to the first end chamber 123 on the upper end side of the piston 100 via the oil passage 121, moves the piston 100 downward, rotates the swash plate, and retreats the combine. Send pressure oil to At this time, the return oil from the second end chamber 124 is returned to the drain via the oil passage 122 → the second port 120 → the third outer peripheral passage 128 → the discharge passage 130 → the inner diameter passage 125. Thus, it can be easily understood from the above description that this configuration corresponds to the manual switching valve 79.

Only when the main shift lever 13 and thus the manual switching valve 79 is in the forward position, the electromagnetic control valve 77
Solenoid 77a for deceleration or solenoid 7 for speed increase
When a predetermined signal is input to 7b, the piston 100 is moved up or down relative to the spool 101 to change and control the rotation angle of the swash plate in the first hydraulic pump 33 for traveling. The connecting pin 136 can be moved up or down by a predetermined amount. For example, in the forward vehicle speed control, a pulse signal having a predetermined duty ratio is given to the speed increasing solenoid 77b, and the pressure oil from the charge pump 71 is supplied to the first end chamber 123 as shown in FIG. When it starts to be sent through 77, hydraulic pressure acts on the upper end of the piston 100 to lower the piston 100.
When the first outer peripheral passage 126 of the spool 101 communicates with the first port 119 of the inner diameter of the piston 100, excess oil is returned from the discharge passage 129 to the drain via the inner diameter passage 125. The first outer peripheral passage 1 of the spool 101
The parallel notch 131 communicating with the first port 119 has the first port 119.
When the communication is established, the flow rate is controlled by the throttle effect of the parallel notch 131. Further, when the piston 100 descends,
The second outer peripheral passage 127 and the second port 120 communicate with each other, and the pressure oil from the charge pump 71 is supplied to the lower end side of the piston 100 via the pump port 118 → the second outer peripheral passage 127 → the second port 120 → the oil passage 122. Although supplied to the second end chamber 124, it is returned to the drain via the return oil circuit on the side of the electromagnetic control valve 77, and a stable state is reached in which the piston 10 is not moved upward (see FIG. 10).

The turning hydraulic servo mechanism 137 for changing and adjusting the angle of the swash plate in the turning second hydraulic pump 36 is disposed near the second hydraulic pump 36 as shown on the left side of FIG. The hydraulic servomechanism 137 for turning and the servo means 72 for traveling (for controlling the vehicle speed) have substantially the same configuration, and the turning of the turning round handle 12 allows the vehicle speed to be changed during turning as described above. To run,
Hydraulic servo mechanism 1 for turning via the connecting pin 136
A piston (not shown) at 37 and a piston 100 at the running servo means 72 are connected and configured to interlock.

Next, the vehicle speed control mode and the deceleration control mode in this configuration will be described. Here, in the vehicle speed control mode, the engine speed is reduced when the load factor of the engine 17 exceeds a certain value during work, and the engine speed is increased when the load factor of the engine 17 is equal to or less than the certain value. This is a control for properly maintaining the engine load while maintaining the vehicle speed, and stabilizing the work by executing this vehicle speed control mode.

On the other hand, in the deceleration control mode, when the load factor of the engine 17 exceeds a certain value during operation, the vehicle speed is reduced by a certain amount or a certain ratio, and when the engine load returns to an appropriate value, the vehicle speed is reduced to the original value. The control is performed so as to return to a set value. In addition to avoiding a hunting phenomenon at the time of changing the vehicle speed due to a change in engine load, the vehicle speed (working speed) is restored at a position of the main transmission lever set in advance. Since the vehicle speed does not exceed the corresponding speed, the vehicle speed does not increase abnormally and safety can be ensured.

Reference numeral 81 shown in FIG. 13 is a control device as control means for executing the vehicle speed control mode and the deceleration control mode by controlling the vehicle speed of the traveling body and controlling the amount of fuel supplied to the engine. When the load factor of the engine becomes equal to or more than a certain value, the inclination angle of the swash plate of the first hydraulic pump 33 is changed and adjusted via the hydraulic servo means 72 to adjust the pressure oil discharge amount. The rotation speed of the first hydraulic motor 34, and thus the vehicle speed, can be decelerated. The control device 81 stores in advance a central processing unit (CPU) that is electronically controlled by a microcomputer or the like, a control program required for arithmetic processing by the central processing unit, initial values, an arithmetic map required for arithmetic operations described later, and the like. A read-only memory (ROM), a read / write memory (RAM) for temporarily storing various input data used for arithmetic processing, an input / output interface, and the like. Connect the parts.

That is, a mode changeover switch 82 for switching between a vehicle speed control mode and a deceleration control mode, a vehicle speed sensor 83 in the traveling section, and an output shaft of the engine 17 or a transmission case for detecting the number of revolutions of the engine 17. An engine speed sensor 84 such as a pulse encoder provided on an output shaft or the like; a load sensor 85 as a load sensor capable of detecting a load state of the engine, which detects a fuel supply amount in a fuel supply device; ON / OFF switch 86 of the mowing clutch device for power-on operation of the threshing unit 3, ON / OFF switch 87 of the threshing clutch device for power-on operation of the threshing unit 3, and the operating position of the main shift lever 13. The lever position sensor 88 and the like are connected to the input port of the control device 81

The output port of the control device 81 has a deceleration solenoid 77a 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, and a speed increase. Solenoid 77b for the right turn and 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, the fuel supply device 84a, and the automatic operation are being performed. And a display device 91 capable of displaying the load state of the engine with characters such as liquid crystal or displaying a load state such as an overload of the working unit with a warning display lamp. Each is connected to an output port.

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 84a includes the engine 17
When the engine 17 is a gasoline engine, it is a fuel injection pump installed at a location such as a throttle valve or an air flow meter of an intake carburetor, and when the engine 17 is a diesel engine, it is a fuel injection pump that injects directly into a cylinder. 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 an adjusting position driving means of the fuel supply amount. It is an actuator such as a step motor which is attached to a rack for adjusting the position of a plunger for adjusting the amount and moves the rack.

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 deceleration control mode will be described. The mode switch 82 is switched to the deceleration control mode. When the main transmission lever 13 is rotated forward from the neutral position (stop position), the vehicle can travel forward at a 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. The main shift lever 13
Is detected by the lever position sensor 88, and when the main shift lever 13 is detected to be in the forward position, the controller (control device) 81 sends the electromagnetic control valve 7
7, the output of the command signal to the main shift lever 13 is allowed.
Is detected at the neutral position (stop position) and the retreat position, the output of the command signal from the controller (control device) 81 to the electromagnetic control valve 77 is prohibited, and the combine moves inadvertently or increases when the combine moves. Safety is ensured by avoiding such situations as speeding up.

As shown in FIG. 14A, 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, the deceleration solenoid 77a of the electromagnetic control valve 77 is supplied with a deceleration continuous drive signal or pulse width modulation regardless of the rotational position of the main transmission lever 13 at the time of forward movement. A pulse signal for control is output, and the holding speed Vs is reduced by a fixed rate (see FIG. 14B).

Next, when the engine load returns to an appropriate value (85% or less of the rated value in the case of 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, an operator riding on the combine can safely operate the vehicle and does not adversely affect the power transmission mechanism.

Next, a control mode in the vehicle speed control mode will be described. In this mode, so-called isochronous control is performed, in which the rotation speed of the engine 17 is kept constant by the electronic governor, and the vehicle speed is controlled in accordance with the load factor of the engine 17 to keep the load on the working machine constant. Is what you do. That is, by decelerating when the load factor of the engine 17 exceeds a certain value, and increasing the speed when the load factor of the engine is less than the certain value, the engine load can be properly adjusted while maintaining the engine speed at the rated speed. This is the control to be held. When the changeover switch 82 is switched to the vehicle speed control mode, the controller 81 sends a control signal to the electronic governor of the fuel supply device 84a to keep the engine speed constant. The electronic governor receiving this signal adjusts the fuel supply amount by moving the rack of the fuel injection pump by the actuator. In the engine speed control unit, when the detected engine speed is different from the set speed due to the load, a number table (table) for obtaining a correction set speed set to return the speed to the set speed. Map) or an arithmetic expression, a table map or an arithmetic expression for obtaining a relationship between a correction set rotation speed when the engine is not loaded and a rack position (a rack position corresponding to no load) at which the rotational speed can be obtained, Rack position (target rack position) required to obtain the set number of rotations from the equivalent rack position and the detected rack position
Is stored, and a maximum allowable position of the rack at each of the rotation speeds is stored.

When the detected rotational speed is different from the set rotational speed due to a change in load, a corrected set rotational speed is calculated, and a rack position corresponding to the no-load corresponding to the corrected set rotational speed is read out. A target rack position is calculated from the rack position and the actual rack position. The engine speed controller outputs to the electronic governor a signal for moving the rack to the target rack position obtained in this manner.

In this embodiment, the engine speed to be kept constant is a predetermined value, for example, a rated speed. The vehicle speed control unit controls the electromagnetic control valve 77 according to the control output signal of the engine speed control unit, and the hydraulic servo means 72 controls the first hydraulic pump 33 for traveling.
The rotation speed is increased by the displacement of the swash plate to make the engine load substantially constant. That is, the load state of the engine is detected by the load sensor (rack position sensor) 85, and the rated engine speed is detected by the engine speed sensor 84. In the control state in which the engine speed is maintained at the rated speed, in order to keep the load factor of the engine at a constant value, a dead zone in which the vehicle speed is not changed is selected in a certain range within the range of movement of the rack position. When the vehicle is located outside the range of the dead zone, control for increasing (decreasing) the vehicle speed is executed. In this case as well, the vehicle speed control mode is set only when the main shift lever 13 is at the forward position.
When the vehicle 3 is in the neutral position and the reverse position, the vehicle speed control mode is not executed.

FIGS. 15 and 16 show another embodiment. The input section of a control device (controller) 81 such as a microcomputer having the same configuration as that of the above-described embodiment has a vehicle speed control mode and a deceleration control mode. Mode switch 82 for switching to the vehicle speed sensor 8 in the traveling section
3. an engine speed sensor 84 such as a pulse encoder provided on the output shaft of the engine 17 or the output shaft of the 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 / OFF switch 86 of a reaping clutch device for power-operating the reaping pre-processing device 4 by turning on. An ON / OFF switch 87 of a threshing clutch device for power-connecting the threshing unit 3 by ON and a lever position sensor 88 for detecting an operation position of the main transmission lever 13 are connected to an input port of the control device 81.

The output port of the control device 81 includes a fuel supply device 84a, an actuator 92 such as a forward / reverse rotatable motor or the like for changing and adjusting the angle of the swash plate of the first hydraulic pump 33 for traveling. Are solenoids 89a and 89b for right and left turn of the electromagnetic control valve for changing and adjusting the angle of the swash plate of the second hydraulic pump 36 for turning, a display lamp 90 for displaying that the automatic operation is being performed, and an engine. Are connected to output ports of the control device 28. The display device 91 is capable of displaying the load state by characters such as liquid crystal or displaying the load state such as overload of the working unit by a warning display lamp. The actuator 92 operates in accordance with an output signal corresponding to a turning position of the main transmission lever 13 such as forward or backward.

In this embodiment, the changeover switch 82
When the control of the vehicle speed mode and the control of the deceleration control mode are executed in response to the mode switching, the rotation position of the swash plate in the first hydraulic pump 33 in FIG. Make your changes. The control mode in the vehicle speed mode and the control mode in the deceleration control mode are almost the same as those in the above-described embodiment, and thus detailed description is omitted.

Also in this embodiment, the main shift lever 13
Is in the vehicle speed control mode and the deceleration control mode only when the vehicle is in the forward position. When the main speed change lever 13 is in the neutral position and the reverse position, the two control modes are not executed. In each of the above embodiments, by switching between the vehicle speed control mode and the deceleration control mode, work conditions, for example, only by vehicle speed control, when cutting and threshing the lodging grain culm, the vehicle speed is faster than the grain culm causing ability of the cutting unit. When troubles occur, or when field conditions and crop conditions are not constant, hunting tends to occur due to vehicle speed control, and the riding comfort of the boarded operator deteriorates. When the mode is switched to the mode, the speed does not become higher than the speed corresponding to the position of the main shift lever set in advance, so that there is an effect that occurrence of trouble and occurrence of hunting can be prevented. In addition, when the field condition and the crop condition are good, the mode can be switched to the vehicle speed control mode, and the work can be streamlined.

As described above, there is an effect that the range of control can be expanded by switching the mode. In addition, it goes without saying that the present invention can be applied to not only the combine but also other types of agricultural working machines and civil engineering 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 partial plan view of a two-pump two-motor type hydraulic stepless speed change mechanism.

FIG. 6 is a partially cutaway front view of a first hydraulic pump portion taken along line VI-VI of FIG. 5;

FIG. 7 is a hydraulic circuit diagram of the first embodiment.

FIG. 8 is a sectional view of the hydraulic servo means when the electromagnetic control valve is neutral.

FIG. 9 is a sectional view of the hydraulic servo means at the beginning of operation.

FIG. 10 is a sectional view of the hydraulic servo means in a stable state.

11A is a longitudinal sectional view of a piston 100, and FIG.
11A is a view taken along line XIb-XIb of FIG. 11A, FIG. 11C is a right side view, FIG. 11D is a right end view of FIG. 11C, and FIG.
FIG. 11A is a view taken along line XIe-XIe, and FIG.
It is a sectional view taken along line XIf-XIf.

12A is a longitudinal sectional view of a spool, and FIG. 12B is an outer peripheral side view of the spool.

FIG. 13 is a functional block diagram of the vehicle speed control device according to the first embodiment.

FIG. 14 (a) shows ON of the engine load and the deceleration command signal.
FIG. 3B is a time chart showing a change in vehicle speed due to ON / OFF of a deceleration command signal.

FIG. 15 is a functional block diagram of a vehicle speed control device according to a second embodiment.

FIG. 16 is a hydraulic circuit diagram of a second embodiment.

[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 72 Hydraulic servo means 79 Manual changeover valve 81 Control device 82 Mode changeover switch 100 Piston 101 Spool

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/14 330 F02D 41/14 330D // F16H 59:30

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 having a vehicle speed control means for detecting and detecting the supply amount and increasing / decreasing a vehicle speed, a swash plate of a hydraulic pump in the hydraulic drive means is operated in association with an operation of a main shift lever to provide hydraulic oil. The vehicle speed control means is configured to be selectively switchable between a vehicle speed control mode and a deceleration control mode. In the vehicle speed control mode, the engine load ratio exceeds a certain value. In the deceleration control mode, it is detected that the load factor of the engine has exceeded a certain value, and the operation of the main shift lever is performed. The vehicle speed is reduced by a fixed ratio or a fixed amount with respect to the holding vehicle speed corresponding to the working position, and when the load of the engine returns to an appropriate value, control is performed to return to the holding vehicle speed in a predetermined time. A vehicle speed control device for a working machine.