JP4984393B2 - Work vehicle - Google Patents

Description

The present invention relates to work vehicles for agriculture, transportation, construction, and the like.

Conventionally, in the technology of a shift control device for a work vehicle, a selector switch is used to select whether an operation angle of an accelerator pedal is input to a controller or an operation angle of a shift lever is input to the controller. When the angle is input to the controller, the engine speed is changed in conjunction with the depression angle of the pedal, and the shift position of the travel disguise device is switched, while when the operation angle of the shift lever is input to the controller, A configuration is known in which the shift position of the travel transmission is switched in conjunction with the operation angle of the lever.
JP 2000-18375 (FIGS. 4 and 5)

The conventional shift control device switches the changeover switch by judging the traveling state of the vehicle by itself. For example, when traveling on a general road at high speed, the shift position is switched using an accelerator pedal, During work, that is, when the load on the vehicle is large, the shift performance is switched by using the shift lever to improve the running performance or the durability of the engine.

However, when such work vehicles are repeatedly operated and moved, it is necessary to operate the changeover switch each time, and there is still room for improvement in order to improve the operability of the vehicle.

In order to solve the above problems, the present invention has taken the following technical means.
That is, the invention according to claim 1 transmits the rotational driving force from the engine (E) to the traveling wheels (4, 5) via the speed change mechanism (3), and the speed change position of the speed change mechanism (3). In the work vehicle that switches according to the operation position of the transmission lever (15),
A shift position sensor (15s) for detecting a shift position of the speed change mechanism (3);
An engine rotation sensor (33) for detecting the actual rotation speed of the engine (E);
A throttle position sensor (35) for detecting the set rotational speed of the engine (E),
“Low speed range”, “medium speed range” and “high speed range” are set in the lever guide (26) of the speed change lever (15), and the speed change lever (15) is moved forward along the lever guide (26). According to the configuration to switch at high speed,
It is determined by the shift position sensor (15s) of the shift lever (15) that the shift position of the transmission mechanism (3) is set within a preset high speed range;
It is determined whether the work machine (R) is raised above a predetermined angle assumed to be a non-working position based on the detection value of the lift arm angle sensor (7s),
The brake pedal sensor (36) determines the connection state of the left and right brake pedals,
When all the conditions are determined, an automatic shift control by the accelerator pedal (19) is performed,
In the automatic shift control by the accelerator pedal (19), the engine speed set by the detection value of the throttle position sensor (35) and the actual engine speed by the engine rotation sensor (33) are compared for each vehicle speed range, A control unit (C) configured to determine whether or not an engine speed corresponding to the set engine speed is detected, and to switch the shift position according to the detected engine speed ,
When the shift lever (15) is operated to the extreme end of the lever guide (26), a shift position sensor (28) for shift control provided at the end of the lever guide (26) is turned on, and the accelerator pedal (19) is used. The work vehicle is characterized by performing automatic shift control .
(Operation of claim 1)
In the work vehicle configured as described above, when the speed change lever (15) is in the high speed range, the work implement (R) is at a predetermined angle or more, and the left and right brake pedals are in the connected state, the accelerator pedal (19) The automatic shift control by is performed. The automatic shift control using the accelerator pedal (19) compares the engine speed set by the detection value of the throttle position sensor (35) with the actual engine speed set by the engine speed sensor (33) for each vehicle speed range, and sets the engine. It is determined whether or not the engine speed corresponding to the speed is detected, and the shift position is switched accordingly.
When the speed change lever (15) is operated to the extreme end of the lever guide (26), the speed control shift position sensor (28) is turned on, and automatic speed change control by the accelerator pedal (19) is performed.

Further, the invention according to claim 2 is characterized in that a differential lock on / off switch (23) is provided to enable automatic shift control by the accelerator pedal (19) when the differential lock device (12) is inactive. The work vehicle according to claim 1 is provided.
(Operation of claim 2)
In the work vehicle configured as described above, in addition to the operation of the first aspect, automatic shift control by the accelerator pedal (19) is enabled when the differential lock device (12) is in an inoperative state.

In the work vehicle according to claim 1 configured as described above, the shift lever (15) is moved forward along the lever guide (26), the shift lever (15) becomes a high speed region, and the work implement (R) Is greater than a predetermined angle, and when the left and right brake pedals are in the connected state, automatic shift control by the accelerator pedal (19) is performed. Then, the shift position is switched by the control unit (C) in conjunction with the engine speed, and there is no need to switch the shift position with the shift lever. For example, the vehicle can be operated by operating the accelerator pedal like an automobile. It is possible to improve the fuel efficiency and the fuel consumption.
Further, when the automatic shift control is operated, the operability of the vehicle can be further improved without requiring detailed attention such as checking the lever position.

Further, in the work vehicle of claim 2, when the differential lock device (12) is in the non-operating state, it is possible to perform the automatic shift control by the accelerator pedal (19), thereby adding the operation requirement of the automatic shift control, thereby improving the operability. Will improve.

Hereinafter, the present invention will be described with respect to a form in which the agricultural tractor 1 is mounted.
As shown in FIG. 1, the tractor 1 is equipped with an engine E at the front of the vehicle body, transmits the rotational power of the engine E to the speed change mechanism 3 in the transmission case 2, and the speed reduced by the speed change mechanism 3 as appropriate. The power is transmitted to the left and right front wheels 4 and the left and right rear wheels 5 to travel. The left and right front wheels 4 are configured so that the steering operation of the steering handle 13 can be freely controlled via a power steering device. The rear wheel 5 includes a brake device for braking the left and right rear wheels 5 and a left and right brake. A differential lock device 12 for stopping the differential action of the rear wheel 5 is provided.

In addition, a cylinder case that houses a working machine ascending / descending cylinder 6 is provided at the rear upper part of the transmission case 2, and the lift arm 7 on the side of the case is rotated up and down by a piston telescopic drive of the cylinder 6. Yes. A lift arm angle sensor 7s is provided at the rotation base of the lift arm 7 as means for detecting the rotation position of the work machine R. As a result, the ground work machine, that is, the rotary work machine R in the example of FIG. 1 is connected to the rear ends of the lower link 9 and the top link 11, and it is detected whether this height is the working position or the non-working position. It is the composition to do.

Further, the left and right lift arms 7 and the lower link 9 are connected by a lift rod 10 and a rolling hydraulic cylinder 10S, and the piston of the cylinder 10S is extended and retracted to move the left and right sides of the working machine R up and down. Thus, the left / right inclined posture is changed.

Further, a steering handle 13 for steering the left and right front wheels 4 to the left and right is provided in front of the cockpit 14 on the vehicle, and the throttle lever 17 for holding the throttle position of the engine E and the forward / backward movement of the vehicle are switched below the handle 13. A forward / reverse switching lever 18 is provided, and an accelerator pedal 19 and a clutch pedal 20 are provided near the lower foot.

The accelerator pedal 19 is linked to the throttle arm 61 on the side of the engine E via a wire or the like, and the amount of depression of the pedal 19 from the rotational position where the rotational speed of the engine E is held by the throttle lever 17. The speed is increased according to the speed.

Further, as shown in FIG. 2, a differential lock on / off switch 23 for switching the differential lock device 12 to ON / OFF is provided below the handle 17, and further, left and right brake pedals 21L and 21R are provided below the handle 17. Yes. Each of the left and right brake pedals 21L and 21R includes a brake connector 22 that can be connected to both pedals, and a brake pedal sensor 36 that detects a use state of the connector 22.

Further, on the side of the cockpit 14, a shift lever 15 and a work machine elevating lever 16 for raising and lowering the work machine are protruded and supported, and potentiometer-type lever position sensors 15 s and 16 s are provided at respective lever bases. Yes.

The transmission mechanism 3 in the mission case 2 includes a main transmission that can switch between four stages from the first speed to the fourth speed, and “high”, “medium”, “ It is configured to have a sub-transmission device that can switch between three stages of “low”, and a combination of these main and sub-transmission devices obtains a total of 12 shift positions (see FIG. 5). Further, the shift positions of the main and auxiliary transmissions are switched by outputting current to the solenoid of the control valve from the shift actuator provided for each.

Further, as shown in FIGS. 3 and 4, the speed change mechanism 3 switches the speed change lever 15 to a high speed position by energizing output of the control unit C described later as it tilts forward along the lever guide 26. It becomes the composition which is done. Also, here, the shift position range from 1 to 4 of the total 12 shift speeds is referred to as “low speed range”, and the shift position range from 5 to 8 shifts is referred to as “medium speed range”. , The shift position range from 9 to 12 stages is set as the “high speed range”.

The speed change lever 15 is provided with a speed change control on / off switch 27 for turning on / off the automatic speed change control of the present invention at the handle of the lever.
Next, the control part C of this invention is demonstrated based on FIG.

The control unit C includes a shift control controller 30 that performs shift control and a work implement controller 50 that controls the attitude of the work implement R, and connects both the controllers 30 and 50 via a communication line. Are mutually transmitted and received.

On the input side of the shift control controller 30, the shift control on / off switch 27, a main shift position sensor 31 and a sub shift position sensor 32 for detecting the state of the shift actuator, and an engine for detecting the rotational speed of the engine E are shown. A rotation sensor 33, a throttle position sensor 35 for detecting the throttle position of the engine E, a brake pedal sensor 36 for detecting whether the left and right brake pedals 21L and 21R are connected or not, and a depression state of the clutch pedal are detected. The clutch pedal sensor 39, the forward switch 37F and the reverse switch 37R at the base of the forward / reverse switching lever 18, the differential lock on / off switch 23, the vehicle speed sensor 29 for detecting the vehicle speed of the tractor 1, and the like are connected.

Further, on the output side of the controller 30, a control valve solenoid 41 for driving the main transmission actuator, a control valve solenoid 42 for driving the auxiliary transmission actuator, and the forward / reverse switching lever 18 are operated to operate the machine body. Are connected to solenoids 43F and 43R of a forward / reverse switching control valve for switching between forward and backward, and a differential lock solenoid 45 for switching the differential lock device 12 between a locked state and an unlocked state.

Further, the work machine controller 50 has a front wheel turning angle sensor 51 for detecting the steering angle of the vehicle on its input side, a lever position sensor 16s at the base of the work machine lifting / lowering lever 16, a work machine rolling control mode setting unit 53, a horizontal A sensor 54, a lift arm angle sensor 7s, and the like are connected, and on the output side of the controller 50, solenoids 56L and 56R of control valves for operating the brake devices for the left and right rear wheels, and the working machine R are moved up and down. Control valve solenoids 57a and 57b, control valve solenoids 58a and 58b for operating the rolling hydraulic cylinder 10s, and the like are connected.

The front wheel turning angle sensor 51 detects the turning operation of the tractor 1 and energizes the solenoids 56L and 56R of the control valves for operating the brake devices for the left and right rear wheels. The work machine rolling control mode setting unit 53 is a sensor that constitutes a so-called auto brake control that brakes the rear wheels. The work machine rolling control mode setting unit 53 uses a ground inclination reference when driving the right and left inclined posture of the work machine R by the rolling cylinder 10S. Or a horizontal reference.

In the tractor 1 configured as described above, as shown in the flowchart of FIG. 7, automatic shift control is performed by the accelerator operation of the present invention.
First, when the power system is turned on by the engine key of the tractor 1, it is determined whether or not the shift control on / off switch 27 is ON. If “ON”, it continues within a predetermined time, for example, within 1 minute. It is determined whether or not the start of traveling of the tractor 1 is detected. As a result, the control is executed as much as possible in the state recognized by the operator, and the vehicle speed is prevented from increasing without knowing that the control is on.

The liquid crystal monitor 24 blinks the characters “road driving mode” within the predetermined time to indicate that the control is set to ON.
Then, it is determined whether or not the position sensor 15s of the base of the speed change lever 15 is set to any operation position in the high speed range, and the working machine R is assumed to be a non-working position based on the detection value of the lift arm angle sensor 7s. It is determined whether or not the angle is raised above a predetermined angle.

Subsequently, whether or not the operation position is below a certain value that is assumed to be traveling on the road by the throttle position sensor 35, or whether the differential lock device 12 is in an inoperative state due to the ON / OFF state of the differential lock on / off switch 23. The brake pedal sensor 36 determines whether the left and right brake pedals are in a connected state, and automatic shift control by the accelerator pedal 19 is performed when these determinations are all YES. ing.

Further, the automatic shift control by the accelerator pedal 19 is performed by comparing the engine speed set by the detection value of the throttle position sensor 35 with the actual engine speed by the engine speed sensor 33 for each vehicle speed range, And determining whether the engine speed corresponding to the set speed is detected and energizing the solenoid of each control valve according to this to change the speed change position to increase / decrease It is said.

In the tractor 1 configured as described above, the shift position is switched in accordance with the engine speed by switching the shift position to any position in the high speed range, and the shift position is set by the shift lever as in the operation. Since it is not necessary to switch and it can drive | work on a road by operation of the accelerator pedal 19 like a motor vehicle, the improvement of operativity and the improvement of a fuel consumption can be aimed at. In particular, since the automatic shift control is activated according to the work position of the work machine R, even when the work is performed at substantially the same speed as the moving speed, such as a spraying work or a scraping work on the tractor 1. During the work, the shift position is maintained, that is, the engine torque is ensured as much as possible, and the workability is not impaired. Further, the operability of the tractor 1 can be improved by accurately operating the control device.

As another form of the invention, the means for determining the shift position of the transmission mechanism 3 may be the operating side, that is, the main shift position sensor and the sub shift position sensor. Further, in a configuration including a shift lever for switching the shift position between the main transmission and the sub-transmission of the tractor 1, as shown in FIG. 8, the shift control on / off switch is used as a condition for performing the automatic shift control. At the same time as the switch 27 is turned on, the main transmission lever may be set to a predetermined speed or higher and the sub transmission lever may be operated when it is in the “high” position.

As another form of the shift lever, as shown in FIG. 9, when the lever 15 is operated to the extreme end position on the high speed side of the guide 26 ', the shift control shift position sensor 28 provided at the guide end is turned on. Thus, the automatic shift control may be “on”. As a result, the operator can improve the operability of the vehicle without requiring detailed attention such as confirming the lever position when operating the shift control.

Next, the mounting structure of the throttle position sensor 35 will be described with reference to FIG.
The throttle position sensor 35 detects the amount of operation of the throttle lever 17 and the accelerator pedal 19 and is linked to the sensor arm 62 and the rod 63, and is connected to the bonnet support member 65 that covers the upper side of the engine E. It is configured to be detachably attached with a fastening screw 67 through an attachment plate 66.

A side view of a tractor. The top view of a tractor. The top view of a transmission lever and a lever guide. The side view which shows the operation mechanism of a transmission lever. Shift position correspondence table The block diagram which shows the connection state of a controller. The control flowchart. The control flowchart which shows another form. The top view of the speed-change lever and lever guide which show another form. (A) Side view of the engine. (B) Side view of the mounting portion of the throttle position sensor. (C) Front view of the mounting portion of the throttle position sensor.

C Control part E Engine R Work implement 3 Transmission mechanism 4 Traveling wheel (front wheel)
5 Running wheel (rear wheel)
7s Lift arm angle sensor 15 Shift lever 15s Shift position sensor 19 Accelerator pedal 26 Lever guide 27 Shift control on / off switch 30 Shift control controller 31 Main shift position sensor 32 Sub shift position sensor 33 Engine rotation sensor 35 Throttle position sensor 36 Brake pedal Sensor 50 Work machine controller

Claims (2)

The rotational driving force from the engine (E) is transmitted to the traveling wheels (4, 5) via the speed change mechanism (3), and the speed change position of the speed change mechanism (3) depends on the operation position of the speed change lever (15). In the work vehicle to switch
A shift position sensor (15s) for detecting a shift position of the speed change mechanism (3);
An engine rotation sensor (33) for detecting the actual rotation speed of the engine (E);
A throttle position sensor (35) for detecting the set rotational speed of the engine (E),
“Low speed range”, “medium speed range” and “high speed range” are set in the lever guide (26) of the speed change lever (15), and the speed change lever (15) is moved forward along the lever guide (26). According to the configuration to switch at high speed,
It is determined by the shift position sensor (15s) of the shift lever (15) that the shift position of the transmission mechanism (3) is set within a preset high speed range;
It is determined whether the work machine (R) is raised above a predetermined angle assumed to be a non-working position based on the detection value of the lift arm angle sensor (7s),
The brake pedal sensor (36) determines the connection state of the left and right brake pedals,
When all the conditions are determined, an automatic shift control by the accelerator pedal (19) is performed,
In the automatic shift control by the accelerator pedal (19), the engine speed set by the detection value of the throttle position sensor (35) and the actual engine speed by the engine rotation sensor (33) are compared for each vehicle speed range, A control unit (C) configured to determine whether or not an engine speed corresponding to the set engine speed is detected, and to switch the shift position according to the detected engine speed ,
When the shift lever (15) is operated to the extreme end of the lever guide (26), a shift position sensor (28) for shift control provided at the end of the lever guide (26) is turned on, and the accelerator pedal (19) is used. A work vehicle characterized by performing automatic shift control . The work vehicle according to claim 1, wherein a differential lock on / off switch (23) is provided to enable automatic shift control by the accelerator pedal (19) when the differential lock device (12) is inactive. .

Images