JP2001349429A - Gear shift control device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily reduce working load without reducing workability when the working load is large, in the working vehicle comprising a transmission operation part for setting a gear shift position of a transmission device and a display part for displaying the gear shift position of the transmission device. SOLUTION: A switch type transmission operation part 36 is provided in a grip part of a transmission lever 18, and the display part 37 displays a transmission indication position corresponding to a transmission command of the transmission operation part 36. When the working load is large, the display part 37 displays a proper gear shift position for keeping an engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a work vehicle, and more particularly to a shift control device for a vehicle having a means for detecting a work load and a display unit for displaying a shift position. .

[0002]

2. Description of the Related Art
This type of work vehicle such as an agricultural tractor includes a work machine connected to be able to move up and down, a means for detecting a work load,
2. Description of the Related Art There is known a shift operation unit that sets a shift position of a transmission, an actuator that switches a shift position according to a shift command of the shift operation unit, and a display unit that displays a shift position of the transmission. .

[0003] However, with the increase in the number of stages of the transmission, there is a possibility that an operator may erroneously recognize a shift instruction position according to a shift instruction of the shift operation section. In particular, when the work load is large, it is difficult to determine to which shift position the transmission is to be shifted.
Further, when the work load is large, it is convenient if it is possible to select whether the load is reduced by lowering the shift position or the load is reduced by raising the work implement according to the work content.

Therefore, in a work vehicle provided with a shift operation portion for setting the shift position of the transmission and a display portion for displaying the shift position of the transmission, the workability is not reduced when the work load is large. A technical problem to be solved arises in order to reduce the load quickly, and an object of the present invention is to solve this problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object, and includes a work machine 16 connected so as to be able to move up and down, a means 75 for detecting a work load, and transmissions 41 and 43. A shift operation section 36 for setting the shift position of
The actuators 60 and 61 for switching the shift position in accordance with the shift command of the shift operation unit 36 and the transmissions 41 and
43, a display unit 37 for displaying the shift position of the vehicle.
In addition to displaying the gear shift command position according to the gear shift command,
When the work load is large, a shift control device for a work vehicle that displays an appropriate shift position of the transmissions 41 and 43 in a different manner from the shift instruction position, and a work machine 16 that is vertically movable. Means for detecting the workload 75
And a shift operation unit 36 for setting a shift position of the transmissions 41 and 43, and actuators 60 and 61 for switching the shift position in accordance with a shift command of the shift operation unit 36. When the workload is large by the workload detection means, the transmission 41,
The shift of the work vehicle provided with the setting means 21 for selecting between a first load control state for lowering the shift position 43 and a second load control state for raising the work implement 16 to a predetermined height when the work load is large. A control device is provided.

[0006]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an agricultural tractor 10 as an example of a working vehicle. An engine 11 is mounted on a front portion of a vehicle body, and after appropriately changing the rotational power of the engine 11 by various transmissions in a transmission case 12 as described later. , To the rear wheel 13 or the front and rear wheels 14, 13. A working machine 16 such as a rotary is connected to a rear portion of the vehicle body via a link device 15 so as to be able to move up and down.

On the other hand, in the vicinity of the driver's seat 17, various levers such as a speed change lever 18 for performing a speed change operation, a position lever 19 for changing the height of the work implement 16, a load automatic control switch 20, a vehicle speed / tilling, and the like. Various switches such as a depth switch 21 are provided. A handle post 24 is provided in front of the driver's seat 17, and a steering handle 25 is mounted on the handle post 24.
By rotating the steering handle 25, the front wheel 14, which is a steered wheel, turns and the vehicle body turns.

A forward / backward switching lever 26 is provided on the side surface of the handle post 24 so as to protrude therefrom.
A meter panel 27 is provided in front of the steering wheel 25, and pedals such as a clutch pedal 28 and left and right brake pedals (not shown) are provided below the steering handle 25.
Reference numeral 30 denotes a controller serving as a control unit described later,
Reference numeral 1 denotes a lift arm angle sensor that detects the height of the working machine.

FIG. 2 shows the speed change lever 18. The speed change lever 18 is projected upward from an h-shaped lever guide 34 and has three speed change patterns of "high speed", "medium speed" and "low speed". By rotating the shift lever 18 along the lever guide 34, the sub-transmission 44 described later is manually switched to one of "high speed", "medium speed", and "low speed" via the link mechanism. Is configured. The grip portion of the shift lever 18 includes a first shift operation portion 35 for setting a shift position of a first main transmission device 41 described later, a first shift device 41 and a second main transmission device 43 described later. And a second shift operation section 36 for setting the shift position of the main shift pattern in which the above-described steps are performed in cooperation with each other.

[0010] The first speed change operation portion 35 is
A pair of momentary switches 35a and 35b are provided, and by operating these switches 35a and 35b, the shift position of the first main transmission 41 is set to "high speed" or "low speed".
Up or down command. In addition, instead of a pair of momentary switches in the horizontal direction, an up or down command is issued by a seesaw type momentary switch, or an up or down command is issued alternately each time a single momentary switch is operated. Is also good.

On the other hand, the second speed change operation section 36 is provided with a pair of momentary switches 36a and 36b in the up and down direction, and combines the first main speed change device 41 and the second main speed change device 43 in cooperation. The main shift pattern is commanded to increase or decrease. An indicator 37 is provided near the shift lever 18 to indicate the shift position of the first main transmission 41 and the second main transmission 43, and the first main transmission 41 and the second main transmission 43 are provided. The current shift position of the main shift pattern combined with the device 43 is displayed.

Alternatively, as shown in FIG. 3, an indicator 38 is provided in the meter panel 27, and the current position of the main transmission pattern in which the first main transmission 41 and the second main transmission 43 are combined in cooperation. And the current position of the subtransmission pattern of the subtransmission 44 may be displayed at the same time. As will be described later, the first main transmission 41 has a two-speed gear shift pattern, and the second main transmission 43 has at least three or more gear shift patterns in the present embodiment. Accordingly, the four stages of the second main transmission 43 can be switched between high and low, respectively, so that the first main transmission 41 and the second main transmission 43
The main speed change pattern in which the speed change pattern is combined with at least six speeds or more, and in the present embodiment, the speed change pattern of eight speeds (first
Speed to the eighth speed), and the auxiliary transmission 4
No. 4 has three sub-shift patterns of three speeds.

FIG. 4 is a diagram of a power transmission system, FIG. 5 is a hydraulic circuit diagram, and FIG. 6 is a block diagram of a shift control system. The rotational power of the engine 11 is intermittently operated by a main clutch 40 in a clutch housing, and is sequentially turned into a first main transmission device 41, a forward / reverse switching device 42 in the transmission case 12,
The transmission is transmitted to the second main transmission 43 and the auxiliary transmission 44.

The first main transmission 41 is "high speed" or "low speed".
This is a transmission having a wet multi-plate Hi-Lo clutch 47 for switching between the two gear sets 45 and 46. If the Hi-Lo clutch valve 48 is switched to the "high speed" position by the controller 30 as control means. , The Hi-L
The o-clutch 47 is turned “on” on the Hi side, and power is transmitted at “high speed” via one gear set 45. Also, Hi
-When the Lo clutch valve 48 is switched to the "low speed" position, the Hi-Lo clutch 47 is turned "on" to the Lo side, via the other gear set 46 having a higher reduction ratio than the one gear set 45. Power is transmitted at "low speed". As described above, the first main transmission device 41 has two high and low gear positions, and the rotational power shifted by the first main transmission device 41 is transmitted to the forward / reverse switching device 42.

The forward / reverse switching device 42 is a transmission having a wet-type multi-plate forward / reverse clutch 51 for switching between two forward and backward gear sets 49 and 50. Side, the forward operation position switch 52 is turned on, and the controller 3
From 0, a signal is sent to the forward solenoid of the forward / backward valve 54, the forward clutch of the forward / backward clutch 51 is turned “on”, and the power is rotated through the one gear set 49 in the forward direction and the power is transmitted to the second main transmission. 43.

On the other hand, when the forward / reverse switching lever 26 is operated to the reverse side, the reverse operation position switch 5
3 is turned on, and the forward / reverse valve 5
3, a signal is sent to the reverse solenoid, and the reverse clutch 51 is turned on by the forward / reverse clutch 51, and the power is transmitted through the other gear set 50 including the counter gear by the reverse rotation to the second main transmission 43. Is transmitted to When the forward / reverse switching lever 26 is in the neutral position, both the forward operation position switch 52 and the reverse operation position switch 53 are turned off, the forward / reverse clutch 51 is turned off, the rotational power is cut off, and the second main speed change is performed. It is not transmitted to the device 43.

The second main transmission 43 is a synchromesh gear type transmission composed of four gear sets. The second main transmission 43 transmits the rotational power output from the forward / reverse switching device 42 to the fourth speed gear set 56, 3 High speed gear set 57, second speed gear set 58,
The power is transmitted to the auxiliary transmission 44 through one of the first-speed gear sets 59. A shifter ring having a synchromesh mechanism is provided between the drive side gears of the fourth speed gear set 56 and the third speed gear set 57, and this shifter ring is slid forward and backward by expansion and contraction of a first shift hydraulic cylinder 60 which is a shift actuator. And the second speed gear set 58
A shifter ring having a synchromesh mechanism is also provided between the drive side gears of the first gear set 59 and the first speed gear set 59, and the shifter ring is configured to slide back and forth by expansion and contraction of a second shift hydraulic cylinder 61 which is a shift actuator. It is.

The main shift "3-4th" from the controller 30
When a signal is sent to the fourth speed solenoid of the valve 62, the first
When the transmission hydraulic cylinder 60 is extended, power is transmitted through the fourth-speed gear set 56 to become “fourth-speed”, and when a signal is sent to the third-speed solenoid of the main-transmission “3-4th-speed” valve 62, Due to the contraction of the first shift hydraulic cylinder 60,
Power is transmitted via the third-speed gear set 57 to “third speed”.
Becomes In addition, the controller 30 sends the main transmission “1-2”
When a signal is sent to the second speed solenoid of the "speed" valve 63,
By the extension of the second shift hydraulic cylinder 61, power is transmitted through the second speed gear set 58 to become “second speed”, and a signal is sent to the first speed solenoid of the main shift “1-2 speed” valve 63. Power is transmitted via the first-speed gear set 59 by the contraction of the second speed-change hydraulic cylinder 61, and "1"
Speed. As described above, the second main transmission 43 has four shift positions from “first speed” to “fourth speed”, and the rotational power shifted by the second main transmission 43 is transmitted to the subtransmission 44. Is transmitted to

The auxiliary transmission device 44 is a sliding mesh gear type transmission device that is switched via a link mechanism by manual operation of the transmission lever 18, and is "low speed".
It has three gear positions, a “medium speed” gear set 65 and 66 and a “high speed” (directly connected) gear set 67. The rotational power shifted by the second main transmission 43 is further shifted by the auxiliary transmission 44.

The second main transmission 43 includes a main transmission "1-N-2" as means for detecting a gear combination.
A "speed" position sensor 68 and a main speed "3-N-4 speed" position sensor 69 are provided. The auxiliary speed change device 44 is provided with a sub speed "low speed" position sensor 70 as a means for detecting a gear combination.
And the sub-shift "medium speed" position sensor 71 and the sub-shift "high speed"
A position sensor 72 is provided. These sensors 6
The detection signals 8 to 72 are sent to the controller 30.

Reference numeral 22 denotes a run / work switch as a means for designating whether the vehicle is in a running state or a working state.
Reference numeral 73 denotes a clutch pedal sensor for detecting a depression operation of the clutch pedal 28, 74 a vehicle speed sensor for detecting a running speed of the vehicle body, and 75 an engine speed sensor as a means for detecting a work load. Reference numeral 77 denotes a power steering device that is operated by rotating the steering handle 25. Reference numeral 78 denotes a four-wheel switching clutch that switches the power transmitted to the front wheels 14 to "constant speed" or "increased speed".
79L and 79R are left and right brake cylinders for independently braking the left and right rear wheels. Further, the working machine lifting / lowering valve 80 is controlled by a signal from the controller 30, and the working machine 16 is moved up and down by expansion and contraction of the lift cylinder 76.

The rotational power shifted by the auxiliary transmission 44 is reduced by a reduction gear 82 of a rear axle via a rear differential 81, and the rear wheel 13 is driven. The rotational power shifted by the auxiliary transmission 44 is also transmitted to the four-wheel drive switching clutch 78, and after being switched to “constant speed” or “increased speed” by the four-wheel drive clutch 78, the front differential device The speed is reduced by a reduction gear 85 of the front axle via 84, and the front wheels 14 are driven. Further, the rotational power of the engine 11 is branched to a PTO system before the main clutch 40, disconnected and connected by a PTO clutch 86, sequentially passed through a PTO reverse rotation device 87 and a PTO transmission 88, and protruded from the rear of the vehicle body. It is transmitted to the PTO take-out shaft 89.

Thus, as shown in FIG. 3 and FIG. 7, the first main transmission 41 and the second main transmission
The main speed change pattern of the gear stage is obtained, and further, the gear ratio of 24 speeds can be obtained by combining the three speed change patterns of the auxiliary speed change device 44. Then, the aforementioned shift lever 18
The first main transmission 41 is switched to either "high speed" or "low speed" by the operation of the first speed change operation unit 35 provided on the gripping portion of the first main transmission 43, and the speed change pattern of the second main transmission 43 is changed to "1st speed". In any case, the current position of the second main transmission 43 is not switched, and only the shift pattern of the first main transmission 41 is moved up or down from the current position. As a result, the speed is increased or decreased by one step. For example, if the Hi switch 35a of the first speed change operation unit 35 is pressed when the linked main speed change pattern is “first speed”, the main speed change pattern is “second speed”.
And the main shift pattern is "6th gear"
At this time, if the Lo switch 35b of the first speed change operation unit 35 is pressed, the main speed change pattern is reduced to the "fifth stage".

On the other hand, by operating the second speed change operation portion 36 provided on the grip portion of the speed change lever 18, a main speed change pattern in which the first main speed change device 41 and the second main speed change device 43 are combined in cooperation is displayed. Move up or down from the position. When the speed-up switch 36a or the speed-reduction switch 36b of the second speed-change operation unit 36 is pressed, the controller 30 presses the speed-up switch 36a or the speed-reduction switch 36b in accordance with the running state or work state of the vehicle body, which will be described later. A first shift control state in which the gear is shifted up or down by one step from the current position for each operation, or the speed-up switch 36a
Alternatively, a second step of raising or lowering the current position by one step at a specified time during the pressing operation of the deceleration switch 36b.
Set to shift control state.

In this embodiment, in the first shift control state, the speed-up switch 36a or the speed-down switch 36
Each time the switch b is pressed, the current position is shifted up or down by one step, but each time the switch is pressed, the position is shifted up or down by two or more steps from the current position (third shift control state). ). In the second shift control state, the speed is increased or decreased by one step from the current position every time the speed-up switch 36a or the deceleration switch 36b is pressed, but two or more steps from the current position every time the switch is pressed. The speed may be increased or decreased step by step (fourth shift control state).

In the first shift control state, for example, if the speed increase switch 36a of the second shift operation section 36 is pressed when the main shift pattern is "first shift", the main shift pattern becomes "2nd shift". If the speed-up switch 36a is pressed when the main speed change pattern is "second speed", the main speed change pattern increases to "third speed". Further, for example, when the main speed change pattern is “sixth stage”, the second speed change operation unit 3
When the speed change switch 36b of No. 6 is pressed, the main speed change pattern is lowered to "5th speed". When the speed change switch 36b is pressed and operated when the main speed change pattern is "5th speed", the main speed change pattern becomes "4". Go down to the "Dai-me".

On the other hand, in the second shift control state, for example, when the main shift pattern is "first gear", the second shift control state is set.
If the speed-up switch 36a of the speed change operation unit 36 is continuously pressed, the main speed change pattern is changed to the "second speed" every specified time.
"3rd stage" ..... sequentially up one stage at a time. In addition, for example, if the deceleration switch 36b of the second speed change operation unit 36 is continuously pressed when the main speed change pattern is “7th speed”,
The main shift pattern is "6th gear", "5th gear" every specified time ...
.., And sequentially down one stage.

On the other hand, as described above with reference to FIGS.
The indicator 37 or 38, which is a display unit that displays all the shift positions of the main shift pattern in which the first main shift device 41 and the second main shift device 43 are combined in cooperation, shows that the first main shift device 41 has a low speed. When shifting to the gear set 46 side,
The left portion (one of the first, third, fifth, and seventh speeds) of the main speed change pattern is displayed, and when the first main speed change device 41 is shifted to the high-speed gear set 45 side, the main speed change pattern is displayed. The right portion (any of second speed, fourth speed, sixth speed, and eighth speed) is displayed.

Therefore, the indicator 37 or 38
The operator can reliably recognize whether the first speed change operation unit 35 can be operated to the "high speed" side or the "low speed" side by the display position of. When the second speed change operation unit 36 is operated to the “increased speed” side, the display moves upward, and the second speed change operation unit 3
When the "6" is operated to the "deceleration" side, the display moves downward, and the change of the shift position becomes clear, and the operability is remarkably improved.

Further, if the indicator 37 or 38 is constituted by a switch having a display function instead of a display lamp, the indicator 37 or 38 not only displays the shift position but also the indicator 3
By pressing the corresponding switch 7 or 38, the main shift pattern can be shifted to a desired shift position.
That is, the gear can be directly shifted to the desired shift position by the indicator 37 or 38, instead of the stepwise shift by the second shift operation section 36.

Here, the load automatic control switch 20
Is set to ON, when the workload increases and the engine speed drops below a predetermined value,
From the controller 30 to the Hi-Lo clutch valve 4
8 or the main transmission "3-4 speed" valve 62 or the main transmission "1-2 speed" valve 63, a signal is sent to control the main transmission pattern to a gear set having a large reduction ratio. (Eg one step down). Therefore, the vehicle speed of the tractor 10 decreases, the work load decreases, and the engine speed returns to the original state. Such a load control state in which the main shift pattern is reduced is referred to as a first load control state.

However, depending on the magnitude of the work load, the engine speed does not return to the original state only by lowering the main speed change pattern by one stage, and it is necessary to further reduce the engine speed by one or more stages. The controller 30 calculates an appropriate shift position according to the magnitude of the work load, and causes the indicator 37 or 38 to display it. For example, when the main shift pattern is shifted by a switch operation of the second shift operation section 36, a shift instruction position by the switch operation is displayed by lighting of a corresponding portion of the indicator 37 or 38. An appropriate shift position of the main shift pattern is displayed by a different display method from the shift instruction position, for example, by flashing a corresponding portion of the indicator 37 or 38. As described above, by changing the display method of the indicator 37 or 38, it is possible to reliably notify the operator of an appropriate shift position when the work load is large.

Therefore, in the first load control state, when the work load is large, the indicator 37 or 38 is first used.
When the worker does not perform the deceleration operation, the main shift pattern is lowered by one step after a predetermined time elapses according to a command from the controller 30 when the worker flashes the corresponding portion. Further, when the work load is large, whether the gear is shifted to an appropriate shift position stepwise by the second
Alternatively, as described above, the indicator 37 or 3
When the switch 8 has a display function, the main switch pattern is directly shifted to an appropriate shift position by pressing the corresponding switch of the indicator 37 or 38.

Here, as a method of load control, there is a second load control state in which the work implement 16 is raised to a predetermined height, in addition to the first load control state in which the main shift pattern is reduced, and It is convenient if any one can be selected according to the work content. In the present invention, by setting the vehicle speed / depth changeover switch 21 provided near the driver's seat 17 to the "vehicle speed" side, the first load control state is established. Lower the shift pattern. On the other hand, when the vehicle speed / cultivation depth switch 21 is set to the "plowing depth" side, a second load control state is established. And the work machine 16 is raised to a predetermined height.

On the other hand, irrespective of the load control, there is a case where the main speed change pattern is skipped by several steps to decelerate at the request of the operator. In such a case, by operating the existing auto-brake device (not shown) and shifting the main shift pattern while decelerating the vehicle body, the shock at the time of deceleration is reduced and the pressure increase control of the auto brake is performed. Subsequently, the pressure control of the forward / reverse valve 54 is performed, and the deceleration shock can be reduced without using the Hi-Lo clutch valve 48 as a proportional pressure control valve. It should be noted that since a large deceleration is not performed in the work in the field, the deceleration control accompanying the automatic brake is executed only when the left and right brake pedals are connected.

Only when the sub-transmission 44 is set to "medium speed" or "low speed", the main transmission pattern can be skipped by several steps, and when the sub-transmission 44 is set to "high speed". Makes it possible to shift the main shift pattern only one step at a time in consideration of safety.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0038]

As described in detail in the above embodiment, the invention according to claim 1 is characterized in that the shift operation portion 36 for setting the shift position of the transmissions 41, 43, and the transmissions 41, 43
And a display unit 37 for displaying the shift position of the shift operation unit 36. The display unit 37 displays a shift instruction position according to the shift instruction of the shift operation unit 36, and when the work load is large. Since the appropriate shift position is displayed in a different manner from the shift instruction position, the possibility of an operator erroneously recognizing the shift position when the shift position is multi-stage is eliminated, and the shift position is determined according to the magnitude of the load. Thus, an appropriate shift position can be determined, and the load can be reduced quickly.

According to a second aspect of the present invention, there is provided a first load control state in which the shift position is lowered when the work load is large, and a second load control state in which the work implement 16 is raised to a predetermined height when the work load is large. Is provided, the load control state can be selected according to the work content, and the operability and convenience can be improved.

[Brief description of the drawings]

 The figure shows an embodiment of the present invention.

FIG. 1 is a side view of a tractor.

FIG. 2 is a perspective view showing a shift lever.

FIG. 3 is a front view showing an indicator of the transmission.

FIG. 4 is a diagram of a power transmission system.

FIG. 5 is a hydraulic circuit diagram.

FIG. 6 is a block diagram of a shift control system.

FIG. 7 is a list showing shift patterns of the transmission.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 automatic load control switch 21 vehicle speed / cultivation depth changeover switch 30 controller 36 second speed change operation part 37 indicator 41 first main transmission 43 second main transmission

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 59:44 F16H 59:44 59:50 59:50 59:70 59:70 63:20 63:20 ( 72) Inventor Shiro Ito 1 Hachikura, Tobe-cho, Toyo-cho, Iyo-gun, Ehime Prefecture, Iseki Agricultural Machinery Co., Ltd. LA02 LA05 LB05 LB15 MA14 PC01 PC07 PD02 QA02 QA03 QA05 QB22 RA02 RA27 RB01 3D036 CA02 CA15 DA01 GA31 GA46 GA48 GH16 GH22 GJ13 3J552 MA04 MA13 MA24 MA25 NA07 NB01 PB10 QB02 RC14 SB02 SB20 VA62Z VB01V

Claims (2)

[Claims] 1. A work machine 16 connected to be able to move up and down, a means 75 for detecting a work load, a shift operation section 36 for setting a shift position of the transmissions 41 and 43, and a shift operation section 36.
In the work vehicle provided with the actuators 60 and 61 for switching the shift position in accordance with the shift command of the transmission device and the display unit 37 for displaying the shift position of the transmissions 41 and 43, the shift operation is performed on the display unit 37. In addition to displaying the shift instruction position according to the shift instruction of the section 36, when the work load is large, the appropriate shift position of the transmissions 41 and 43 is displayed differently from the shift instruction position. A shift control device for a work vehicle. 2. A work machine 16 which is connected to be able to move up and down, means 75 for detecting a work load, a shift operation section 36 for setting a shift position of the transmissions 41 and 43, and a shift operation section 36.
And the actuators 60 and 61 for switching the shift position in accordance with the shift command of the work vehicle, the work vehicle includes a shift position of the transmissions 41 and 43 when the work load is large by the work load detecting means. A setting means 21 for selecting between a first load control state in which the work load is lowered and a second load control state in which the work implement 16 is raised to a predetermined height when the work load is large. Transmission control device.