JP2015004439A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tractor which can perform traveling and stop by a single operation of a brake pedal without operating a clutch pedal.SOLUTION: In a tractor, a forward/reverse clutch 48 for switching advance and backing to a neutral position is arranged in a power transmission passage to traveling devices such as front wheels 2 and rear wheels 3 from an engine 5, the traveling device is made to operate a brake 135 accompanied by the pedal-in of brake pedals 19L, 19R, the connection operation pressure of the forward/reverse clutch 48 is lowered, the forward/reverse clutch 48 is held at stop operation pressure being prescribed low pressure when a machine body is in a traveling stop state, and the stop operation pressure of the forward/reverse clutch 48 is set to be higher as a gear change position of a sub-gear shift change lever 15 is at a high-speed side.

Description

  The present invention relates to a tractor that is an agricultural machine, and more particularly to a braking control device for a tractor.

  The tractor is provided with a plurality of clutches, a transmission, and the like in the power transmission device in order to transmit engine power to traveling devices such as front wheels and rear wheels. The aircraft has an accelerator pedal, a brake pedal, and a clutch pedal. When the vehicle stops traveling, it is common to apply the brake by depressing the brake pedal and to decouple the clutch clutch by depressing the clutch pedal. However, it is troublesome to frequently disengage and brake the clutch during frequent travel and stop. Therefore, the clutch is automatically disengaged only by the brake operation and the aircraft is stopped. By simply releasing the brake and releasing the brake, the clutch is automatically engaged to allow the vehicle to run.

  For example, in the brake control device for a work vehicle described in Japanese Patent Application Laid-Open No. 2012-116301, there is a technology in which the airframe is stopped by automatically disengaging the power transmission clutch of the power transmission device in accordance with the depression operation of the brake pedal. It is disclosed.

JP 2012-116301 A

  In the brake control device for a work vehicle described above, when the disconnection operation of the hydraulic multi-plate clutch is automatically performed as the brake pedal is depressed, the connection pressure of the hydraulic multi-plate clutch is set to zero. Since the connection response of the hydraulic multi-plate clutch is poor when starting the vehicle, there is a problem that the start is delayed.

  Therefore, an object of the present invention is to provide a tractor that can smoothly run and stop by operating a brake.

The problems of the present invention are solved by the following technical means.
The invention according to claim 1 is provided with a forward / reverse clutch (48) for switching between forward / reverse and neutral on a power transmission path from the engine (5) to a traveling device such as the front wheels (2) and the rear wheels (3), When the pedals (19L) and (19R) are depressed, the travel device is actuated with the brake (135) and the connection operating pressure of the forward / reverse clutch (48) is reduced. The clutch (48) is held at a predetermined low stop operating pressure, and the stop operating pressure of the forward / reverse clutch (48) is set higher as the shift position of the auxiliary transmission lever (15) is higher. The tractor is characterized by this.

  The invention according to claim 2 is configured such that the power of the forward / reverse clutch (48) can be turned on and off by operating the clutch pedal (1002), and the brake pedal (19L), without stepping on the clutch pedal (1002), The tractor according to claim 1, further comprising an informing unit (146) for informing a state where the airframe can be stopped only by an operation of (19R).

  According to a third aspect of the present invention, when the brake pedal (19L), (19R) is released, the auxiliary transmission lever (15 The tractor according to claim 1 or 2, wherein a higher gear position is set at a higher speed side.

  According to a fourth aspect of the present invention, when the accelerator pedal (18) is depressed after the brake pedals (19L) and (19R) are released, the brake pedals (19L) and (19R) are released. The tractor according to any one of claims 1 to 3, wherein the stop operating pressure is returned to the connection operating pressure of the total pressure at a pressure increasing rate higher than the pressure increasing rate at the time.

  In the first aspect of the invention, when the brake pedals 19L and 19R are depressed, the connection operating pressure is reduced without completely disengaging the forward / reverse clutch 48, and the pressure is maintained at the low stop operating pressure. And the brake 135 act | operates to a traveling apparatus.

  Thus, since the low pressure is applied to the forward / reverse clutch 48 even when the airframe is stopped, the forward / reverse clutch 48 is quickly and completely connected when the vehicle starts running from the stopped state, so that smooth You can start.

  Further, since the stop operating pressure of the forward / reverse clutch 48 is set higher as the shift position of the auxiliary transmission lever 15 is higher, the target speed can be reached earlier as the target speed is higher. Become.

  In the second aspect of the present invention, the notifying means 146 is provided for notifying that the airframe can be stopped only by operating the brake pedals 19L and 19R without stepping on the clutch pedal 1002. It can be visually recognized.

  According to the third aspect of the present invention, when the brake pedals 19L and 19R are released, the pressure increase rate for returning the connection operating pressure of the forward / reverse clutch 48 to the full pressure is increased as the shift position of the auxiliary transmission lever 15 is higher. Since the target speed is higher, the target speed can be reached earlier.

  In the invention according to claim 4, when the depression of the accelerator pedal 18 is performed after the depression of the brake pedals 19L, 19R is released, the pressure increase rate is higher than the pressure increase rate when the depression of the brake pedals 19L, 19R is released. Since the stop operating pressure is returned to the full connection operating pressure, the target speed can be reached quickly.

(A) It is the whole tractor shown as a work vehicle of the present invention. (B) It is a top view of a brake pedal and an accelerator pedal part. It is a power transmission diagram from the engine to the front and rear wheels and the PTO shaft. It is a cross-sectional development view of a mission case. It is a front sectional view of a mission case. It is a section perspective view of a mission case. It is a front view of a front panel. It is a left side perspective view of a steering handle. It is an automatic control block diagram. It is a control flowchart figure of clutch holding pressure. It is a control flowchart figure of a no clutch brake. It is a gear position control flowchart figure at the time of a brake. It is a control flowchart figure at the time of a no clutch brake release. It is a graph of the full pressure return of the forward / backward clutch operating hydraulic pressure.

An example of a tractor as an example of a work vehicle will be described below.
In the present specification, the left and right directions in the forward direction of the work vehicle are referred to as left and right, respectively, the forward direction is referred to as front, and the reverse direction is referred to as rear.

  As shown in FIG. 1, the tractor 1 includes front wheels 2, 2 and rear wheels 3, 3 at the front and rear portions of the fuselage, and the rotation of the engine output shaft 20 of the engine 5 mounted on the front portion of the fuselage The transmission is decelerated as appropriate and transmitted to the front wheels 2 and 2 and the rear wheels 3 and 3. The rear wheels 3 and 3 may be crawlers.

  A steering handle 7 is provided on the handle post 6 at the center of the machine body, and a seat 9 is provided behind the steering handle 7. A forward / reverse lever 10 is provided on the lower left side of the steering handle 7 to switch the advancing direction of the airframe between the forward direction and the reverse direction. When the forward / reverse lever 10 is shifted to the front side, the airframe moves forward, and when it is shifted to the rear side, it moves backward. The forward / reverse lever 10 is configured to be operated with a fingertip while holding the steering handle 7.

  For this reason, the protruding portion 10a of the forward / reverse lever 10 protruding from the handle post 6 has a refracting portion 10b and has a gripping portion 10c upward. For this reason, the grip portion 10c can be operated with the fingertip while the steering handle 7 is being gripped. When the forward / reverse lever 10 is slightly lifted and moved forward, the forward position is reached, and when the forward / backward lever 10 is lifted slightly and moved backward, the reverse position is reached.

  An accelerator lever 11 for adjusting the engine speed is provided on the opposite side of the forward / reverse lever 10 with the handle post 6 in between, and an accelerator for similarly adjusting the engine speed is provided at the right corner of the step floor 13. A left brake pedal 19L and a right brake pedal 19R for operating a pedal 135 and a brake 135 provided on each of the left and right rear wheels 3, 3 are provided.

  A brake connecting rod 94 for integrally connecting the left brake pedal 19L and the right brake pedal 19R is provided, and when either the left brake pedal 19L or the right brake pedal 19R is depressed with the brake connecting rod 94 connected, the tractor 1 The travel stops, and the stop control will be described later.

  When the brake connecting rod 94 is in a non-connected state, the left brake pedal 19L and the right brake pedal 19R can be used independently, and the turning radius can be increased by depressing the brake pedal inside the turning when turning in the field. Can turn small (manual brake turn).

A clutch pedal 1002 is provided on the opposite side of the left brake pedal 19L and the right brake pedal 19R across the handle post 6.
A front meter panel 16 shown in FIG. 1 is provided on the front side of the steering handle 7 above the handle post 6, and a liquid crystal display unit 1001 is provided at the center of the front meter panel 16. A tachometer 136 is provided on the left side of the liquid crystal display unit 1001, and an indicator lamp panel 145 is provided on the right side of the liquid crystal display unit 1001.

  The engine speed is displayed on the tachometer 136, and a no-kura indicator lamp 146 and a low-pressure warning lamp 147 are provided on the indicator lamp panel 145. As shown in FIG. 7, a no-clutch switch 126 is provided at the lower left portion of the handle post 6. A display change-over switch 1000 is provided on the right side of the no-clutch switch 126, and the content displayed on the liquid crystal display unit 1001 is switched every time the display change-over switch 1000 is pressed.

  The main transmission lever 14 for shifting from the first speed to the eighth speed is located on the left front side of the seat 9, and the sub-transmission lever 15 can select any one of the super-low speed, low-speed, medium-speed, high-speed four-stage and neutral positions. Is on the rear side thereof, and further, on the right side thereof, a PTO speed change lever 12 for shifting in four steps is provided.

A rotary working machine 17 is mounted on the rear part of the tractor 1 and is driven by a PTO output shaft 111 protruding rearward from the mission case 8.
FIG. 2 is a transmission line diagram showing a power transmission mechanism of the transmission in the transmission case 8 in which the front case 8F and the rear case 8R are assembled together, from the engine 5 to the front wheels 2, the rear wheels 3, and the rotary work machine 17. A transmission transmission mechanism for the PTO output shaft 111 will be described.

  The rotation of the engine output shaft 20 of the engine 5 is transmitted to the input shaft 21 in the mission case 8. The first input gear 22 and the second input gear 23 fixed to the input shaft 21 are a first low speed gear 26 of the first high / low clutch 24, a second low speed gear 27 of the second high / low clutch 25, and the first input gear 21, respectively. The first high speed gear 30 of the high / low clutch 24 and the second high speed gear 31 of the second high / low clutch 25 are engaged with each other to transmit the rotation.

  When the first high / low clutch 24 is connected to the first low speed gear 26 side, the first low speed gear 26 is transmitted to the first clutch shaft 28, and when the first high / low clutch 24 is connected to the first high speed gear 30 side, When the second high / low clutch 25 is connected to the second low speed gear 27 side, the second high / low clutch 25 is connected to the second clutch shaft 29 and connected to the second high speed gear 31 side. It is transmitted from the second high speed gear 31 to the second clutch shaft 29.

  The first high / low clutch 24 and the second high / low clutch 25 are the same hydraulic multi-plate clutch, and the first clutch shaft 28 decelerates the rotation of the input shaft 21 in two stages of high and low at the same reduction ratio. And transmitted to the second clutch shaft 29.

  Further, as shown in FIG. 4, the first high / low clutch 24 and the second high / low clutch 25 are immersed in the lubricating oil, and the first clutch shaft 28 and the second clutch shaft 29 are separated from the liquid level OL of the lubricating oil. Located slightly above.

  Further, as shown in FIG. 3, the lubrication machined by drilling from the left and right opening side of the case to the built-up portion 181 a formed on the front partition wall 181 that supports the first clutch shaft 28 and the second clutch shaft 29 to the transmission case 8. A hole 8b is provided to supply oil to the shafts of the first high / low clutch 24 and the second high / low clutch 25 from the oil supply hole 8b.

Further, as shown in FIG. 5, the first high / low clutch 24 and the second high / low clutch 25 are arranged on the left and right in the lower part of the downward inclined portion 8 c of the mission case 8.
The first gear 113 fixed to the first clutch shaft 28 shown in FIG. 2 meshes with the second gear 35 fixed to the low-speed transmission shaft 34 and is decelerated and transmitted, and the third gear 149 fixed to the second clutch shaft 29 is transmitted. The fourth gear 33 fixed to the high-speed transmission shaft 32 meshes with the fourth gear 33 to increase the transmission.

With the speed change transmission up to this point, the low speed transmission shaft 34 is shifted in two stages at a low speed, and the high speed transmission shaft 32 is shifted in two stages at a high speed, so that a total of four speeds are achieved.
The rotation of the low-speed transmission shaft 34 and the high-speed transmission shaft 32 is transmitted to the first sync change 42 and the second sync change 36 respectively, and the first sync small gear 43 of the first sync change 42 and the second sync of the second sync change 36. The small gear 37 meshes with the fifth gear 40 of the first transmission shaft 39, and the first synchronization gear large 44 of the first synchronization change 42 and the second synchronization large gear 38 of the second synchronization change 36 are the first transmission shaft 39. Engage with the six gears 41 to transmit.

  The first sync small gear 43 and the first sync large gear 44 of the first sync change 42 and the second sync small gear 37 and the second sync large gear 38 of the second sync change 36 are exactly the same gear and have a low speed transmission shaft. Since 34 is rotated at a low speed and the high-speed transmission shaft 32 is rotated at a high speed, when the first sync change 42 is switched, the gear is further shifted in two steps at a low speed, and when the second sync change 36 is switched, the gear is shifted in two steps at a high speed. The That is, the rotation of the first input shaft 21 is shifted by the first transmission shaft 39 between the low speed four stages and the high speed four stages.

  The first sync change 42 and the second sync change 36 are accommodated in the transmission case 8 with the shifter stay and the shifter being sub-assembled, and the case openings of the speed change operation portion are provided on the left and right sides of the case. It is provided above the liquid level OL of the lubricating oil.

  The shift position of the main shift lever 14 operated by the operator is read by the main transmission section 150 so far, and the high / low hydraulic multi-plate clutches 24 and 25 and the first and second sync change are automatically performed by the travel system ECU 120. 36 and 42 are controlled so that the speed is changed to a low-speed four-stage and a high-speed four-stage (eight-stage shift).

  Further, in the transmission case 8, the first high / low clutch 24 and the second high / low clutch 25 are arranged on the left and right, and the low-speed transmission shaft 34 and the second sync change which are fitted with the first sync change 42 on the lower side. Since the high-speed transmission shaft 32 on which the 36 is mounted is arranged on the left and right, the left and right width of the transmission case 8 is narrow and the height can be reduced.

  Further, the first transmission shaft 39 is connected to the second transmission shaft 45 by shaft connection. A seventh gear 46 and an eighth gear 47 are fixed to the second transmission shaft 45, and meshed with a forward clutch gear 49 of a hydraulic multi-plate forward / reverse clutch 48 and a reverse gear 51 of a reverse shaft 52. 51 meshes with the reverse clutch gear 50 of the forward / reverse clutch 48.

  Therefore, when the forward clutch 48a of the forward / reverse clutch 48 is connected and connected to the forward clutch gear 49, it is transmitted to the auxiliary transmission shaft 53 connected to the forward / rearward clutch 48 in the forward rotation state (forward movement). When the reverse clutch 48b is connected to the reverse clutch gear 50, it is transmitted to the auxiliary transmission shaft 53 in the reverse state (reverse). The reduction ratio is different between forward rotation and reverse rotation, and the reverse rotation is slower. When the forward / reverse lever 10 is set to the forward position, the forward clutch 48a is connected, and when the forward / backward lever 10 is set to the reverse position, the reverse clutch 48b is connected.

  Further, an oil supply hole 182b drilled from the outside of the case case is provided in the built-up portion 182a formed on the rear partition wall 182 that supports the support shaft of the forward / reverse clutch 48 on the transmission case 8, and the front and rear of the oil supply hole 182b Oil is supplied to the support shaft of the advance clutch 48.

An oil supply hole for the front wheel acceleration clutch 79 and the PTO main clutch 97 is also formed in a built-up portion provided inside the transmission case 8.
Next, the auxiliary transmission unit 154 will be described.

  A ninth gear 54 and a tenth gear 55 are fixed to the auxiliary transmission shaft 53 and mesh with the third sync large gear 56 and the third sync small gear 59 of the third sync change 58, respectively. Accordingly, when the third sync change 58 is connected to the third sync large gear 56 side, the fifth transmission shaft 60 is accelerated by the rotation transmitted from the ninth gear 54 to the third sync large gear 56 and driven at a high speed. When the third sync change 58 is connected to the third sync small gear 59 side, the fifth transmission shaft 60 is decelerated by the rotation transmitted from the tenth gear 55 to the third sync small gear 59 and driven at medium speed.

  Further, an eleventh gear 57 is fixed to the third sync change gear 58 on the side of the third sync change gear 59 and meshes with the fourth sync change gear 69 of the fourth sync change 71. The fifteenth gear 70 is fixed to the fourth synchro small gear 69 side, and the fifteenth gear 70 meshes with the seventeenth gear 75 of the second cylindrical shaft 114 and is fixed to the second cylindrical shaft 114. The eighteenth gear 76 is transmitted to the fourth synchro large gear 72. A sixteenth gear 74 is fixed to the first cylinder shaft 73 on which the fourth sync change 71 is mounted.

  Accordingly, when the third sync change 58 is made neutral, the rotation of the tenth gear 55 is transmitted to the third sync small gear 59, and the eleventh gear 57 fixed to the third sync small gear 59 side to the fourth sync small gear. It is transmitted to 69.

  In this state, when the fourth sync change 71 is connected to the fourth sync small gear 69 side, the rotation of the fourth sync small gear 69 becomes the rotation of the sixteenth gear 74 and the speed is lowered. When connected to the fourth synchro large gear 72 side, the rotation of the fourth synchro small gear 69 is transmitted from the fifteenth gear 70 to the seventeenth gear 75, the eighteenth gear 76, and the fourth synchro large gear 72, and the sixteenth gear. 74 becomes extremely low speed.

When the third sync change 58 is connected to the third sync large gear 56 side or the third sync small gear 59 side, the fourth sync change 71 is made neutral.
Therefore, the low-speed four-speed and the high-speed four-speed shifted by the main transmission unit 150 are shifted to the four-speed by the sub-transmission unit 154, so that the speed is changed to the low-speed 16-speed and the high-speed 16-speed (total of 32 speeds). Will be. As a result, the forward / reverse clutch 48 is switched to provide a forward 32 shift and reverse 32 shift.

  Further, the sixteenth gear 74 is engaged with the twelfth gear 61 fixed to the fifth transmission shaft 60 to drive the fifth transmission shaft 60. The first bevel gear 62 fixed to the shaft end of the fifth transmission shaft 60 meshes with the second bevel gear 63 of the rear bevel case 64, and from the bevel output shaft 65 of the rear bevel case 64 to the thirteenth gear 66 and the fourteenth gear. The rear wheel output shaft 68 is rotated via the gear 67 to drive the rear wheel 3. The left and right rear wheel output shafts 68 are provided with brakes 135 that are operated by the right brake pedal 19R and the left brake pedal 19L, respectively.

  A twenty-first gear 117 is fixed to the fifth transmission shaft 60, and a twenty-second gear 118 and a twenty-second gear 148 fixed to a second cylindrical shaft 119 supported by the auxiliary transmission shaft 53 are provided. Thus, the sixteenth gear 77 of the first front wheel drive shaft 78 is transmitted to the nineteenth gear 77, and the sixteenth gear 74 is rotated to the first front wheel drive shaft 78 by the low-speed sixteenth and high-speed sixteenth rotations.

  The first front wheel drive shaft 78 is transmitted to the second front wheel drive shaft 84 via the front wheel speed increasing clutch 79, and is transferred to the third front wheel drive shaft 85, the fourth front wheel drive shaft 86, and the front wheel drive bevel shaft 87. The first front bevel gear 88 fixed to the shaft end of the front wheel drive bevel shaft 87 is meshed with the second front bevel gear 115 of the front bevel case 89, and the first front bevel gear set 91 extends from the front bevel output shaft 90 of the front bevel case 89. The front wheel output shaft 93 is rotated via the front longitudinal axis 116 and the second front bevel gear set 92 to drive the front wheel 2.

  When the speed increasing clutch 79b of the front wheel speed increasing clutch 79 is connected, the first speed increasing clutch gear 82, the first speed increasing gear 83, the first speed increasing gear 83, the second speed increasing clutch gear 80, and the second front wheel driving shaft 84 are connected. This flow is transmitted to increase the speed of the front wheel relative to the rear wheel. When the 4WD clutch 79 a of the front wheel acceleration clutch 79 is connected, the rotation of the first acceleration clutch gear 82 is transmitted to the second front wheel drive shaft 84. This flow is a 4WD drive that makes the front wheels the same speed as the rear wheels. When neither the speed increasing clutch 79b nor the 4WD clutch 79a is connected, 2WD traveling with only rear wheel driving is performed.

The sub-transmission unit 154 reads the shift position of the sub-transmission lever 15, and the traveling ECU 120 automatically controls the third sync change 58 and the fourth sync change 71 to change the speed.
Further, the first cylinder shaft 73 to which the fourth sync change 71 is attached is disposed below the fifth transmission shaft 60 to which the third sync change 58 is attached, so that the length of the transmission case 8 can be shortened. The third sync change 58 and the fourth sync change 71 may be connected to the auxiliary transmission lever 15 by a link mechanism or the like to constitute a mechanical change.

Next, the transmission path of the PTO output shaft 111 will be described.
The main clutch gear 96 of the PTO main clutch 97 is engaged with the second input gear 23, and the power is interrupted by the PTO main clutch 97. As shown in FIG. 5, the PTO main clutch 97 is positioned below the first high / low clutch 24 and the second high / low clutch 25 and is cooled and lubricated with lubricating oil accumulated in the transmission case 8. The

The first PTO shaft 95 to which the PTO main clutch 97 is attached is provided with a PTO transmission 157 as follows.
The first PTO gear 98, the second PTO gear 99, the fifth synchro small gear 100 of the fifth sync change 151 and the fifth synchro large gear 101 are mounted, and the twentieth gear 102 and the twentieth gear 20 are attached to the second PTO shaft 104. The three gears 152, the twenty-first gear 103 and the twenty-fourth gear 153 are fixed, and the PTO reverse rotation gear 105 is pivotally supported on the counter shaft 106.

  When the first PTO gear 98 is slid and meshed with the twentieth gear 102, the third PTO shaft 107 becomes the second speed, and when the first PTO gear 98 is slid and engaged with the second PTO gear 99, the first PTO When the rotation of the shaft 95 is transmitted to the third PTO shaft 107 through the second PTO gear 99 and the twenty-third gear 152 to become the fourth speed, and the fifth sync change 151 is connected to the fifth sync small gear 100, the fifth sync. When the fifth synchro change gear 151 is connected to the fifth synchro large gear 101 from the small gear 100 to the twenty-first gear 103, the fifth gear is transmitted from the fifth synchro large gear 101 to the twenty-fourth gear 153. When the third speed is established and the PTO reverse rotation gear 105 is engaged with the first PTO gear 98 and the twentieth gear 102, the rotation of the first PTO shaft 95 is changed from the first PTO gear 98 to the PTO reverse rotation gear 105. Article is transmitted to the gear 102 becomes reverse rotation transmitted to the third PTO shaft 107 Te.

  As shown in FIG. 5, the first PTO gear 98, the second PTO gear 99, and the fifth sync change 151 include the first high / low clutch 24, the second high / low clutch 25, the first sync change 42, and The second synchro change 36 is disposed on the lower side.

  The rotation of the third PTO shaft 107 is transmitted to the fifth PTO shaft 108 via the fourth PTO shaft 156, and further decelerated by the transmission from the first PTO output gear 109 to the second PTO output gear 110, and the PTO output shaft 111 is driven.

  As shown in FIG. 4, the input shaft 21 and the fourth front wheel drive shaft 86 are located in the center of the left and right of the transmission case 8, and the first high / low clutch 24 and the second high / low clutch 25, the high speed transmission shaft 32 and the low speed transmission. The shaft 34, the fourth PTO shaft 156, and the auxiliary transmission shaft 53 are arranged in a symmetrical position.

Further, the fourth PTO shaft 156, the auxiliary transmission shaft 53 and the fourth front wheel drive shaft 86 are arranged in a substantially isosceles triangle in front view at a position inside the transmission case 8.
FIG. 8 is a control block diagram of automatic control for controlling the shift in the mission case 8. Input of control data to the travel system ECU 120 includes an on / off signal from the clutch pedal sensor 121, a travel speed of the vehicle speed sensor 122, and the like. The on / off signal of the right brake sensor 123R, the on / off signal of the left brake sensor 123L, the switching signal of the forward / reverse selector switch 124, the on / off signal of the brake connection sensor 125, and the on / off signal of the no-clutch switch 126 Off signal.

  The control output from the traveling system ECU 120 includes an operation signal to the forward solenoid 127 and the reverse solenoid 128, an operation signal to the brake proportional solenoid 129, an operation signal to the right brake solenoid 130R and the left brake solenoid 130L, and a high speed proportional solenoid. 132 and an operation signal to the low-speed proportional solenoid 133.

Next, braking control will be described.
As described above, when the left brake pedal 19L and the right brake pedal 19R are depressed, the brake 135 on the depressed side is actuated to turn to the activated side.

  When the brake connection sensor 125 detects that the left brake pedal 19L and the right brake pedal 19R are connected by the brake connecting rod 94 and detects that the no-clutch switch 126 is turned on, a “no-clutch brake operation state” is set. . In this state, the no-kura indicator lamp 146 of the indicator lamp panel 145 is turned on. In addition, when the brake connection sensor 125 is in the non-connected state, the no-kura indicator lamp 146 blinks to notify that the “no clutch brake operating state” is not functioning. “No clutch brake operating state” means that the airframe can be stopped and started without stepping on the clutch pedal.

  Even if the main key switch is stopped, if the no-clutch switch 126 is on, it is memorized as an on-state. Therefore, when the main key switch is turned on again, the “no-clutch brake operation state” is entered, and the no-clutch indicator 146 Lights up. At this time, when the brake connection sensor 125 is in the non-connected state, the no-kura indicator lamp 146 blinks.

  During traveling, when the right brake pedal 19R or the left brake pedal 19L is depressed with the no-clutch brake activated, that is, when the left and right brake pedals 19L and 19R are depressed simultaneously, the right brake sensor 123R or the left brake sensor 123L is Detect depressing operation. The clutch on the side of the forward clutch 48a or the reverse clutch 48b of the forward / reverse clutch 48 is in a low pressure state (half clutch state). In this half-clutch state, the left and right brakes 135 are operated to bring the aircraft to a stop state. When the brake pedal is depressed, the low pressure warning lamp 147 of the indicator lamp panel 145 is turned on. The right brake sensor 123R and the left brake sensor 123L are on / off type sensors.

  If the low-pressure stop state continues for a long time (about 2 minutes), the oil temperature becomes high, so that the lighting state of the low-pressure warning lamp 147 blinks to notify the operator. At this time, when the clutch pedal 1002 is depressed or the forward / reverse lever 10 is set to the neutral position, the low pressure state of the forward clutch 48a or the reverse clutch 48b of the forward / reverse clutch 48 is released. Thus, the half-clutch state is completely neutralized. At this time, the nokura indicator light 146 is turned off.

  In order to start again when the aircraft is stopped in the “no clutch brake operation state”, power is transmitted in the low pressure stop state (half-clutch) state by releasing the brake pedal and releasing the brake pedal. So, the response is good and the start starts smoothly. Thereafter, the pressure is gradually increased, and the clutch is completely connected after a specified time. When it is desired to accelerate quickly, the accelerator pedal 18 is stepped on to increase the engine speed, thereby rapidly accelerating.

  When the sub-shift is in the neutral position when starting in the initial state, the no-clutch switch 126 is turned on and the brake pedal is depressed. Then, the clutch pedal 1002 is depressed to shift the auxiliary transmission lever 15. The main transmission lever 14 is also operated for shifting. Thereafter, the forward / reverse lever 10 is operated forward or backward. Then, the foot is released from the clutch pedal 1002, and the clutch pedal 1002 is released. In this state, the airframe is stopped in a “no clutch brake operation state”.

  In the “no clutch brake operating state”, when the brake pedal is depressed, if the clutch pedal 1002 is depressed, the “no clutch brake operating state” does not function.

  If the no-clutch switch 126 is pressed while both the brake pedal and the clutch pedal 1002 are depressed in the “no-clutch brake operating state”, the “no-clutch brake operating state” is released and does not function.

  If the no-clutch switch 126 is pressed when both the brake pedal and the clutch pedal 1002 are not depressed in the “no-clutch brake operation state”, the “no-clutch brake operation state” is released and does not function.

  When the brake connection sensor 125 is not connected in the “no clutch brake operation state” when the brake pedal is not depressed and stopped, the function of the “no clutch brake operation state” is temporarily interrupted.

  In the “no clutch brake operation state”, when the brake pedal is depressed and stopped, the function of the “no clutch brake operation state” is not temporarily interrupted even if the brake connection sensor 125 is disconnected. After that, when the depression operation of the brake pedal is released, the “no clutch brake operation state” function is temporarily suspended. However, when the brake pedal depression operation is released and the brake connection sensor 125 is connected again, the “no clutch brake operation state” function is not temporarily suspended.

  Even when the “no clutch brake operation state” function is temporarily suspended, the “no clutch brake operation state” function is maintained even if the no clutch switch 126 is pressed.

  The no-kura indicator lamp 146 is turned on when the function of “no clutch brake operation state” is entered and the brake pedal is not stopped. Flashes when stopped with the brake pedal. Further, when the “no clutch brake operation state” function is turned off or the “no clutch brake operation state” function is temporarily suspended, the light is turned off.

  The low-pressure warning light 147 enters the function of “no clutch brake operation state” and blinks when stopped by the brake pedal. When the brake pedal is stopped for 2 minutes or longer, it flashes rapidly.

As shown in FIG. 9, the low-pressure stop pressure of the forward / reverse clutch 48 in the no-clutch brake operating state is changed according to the shift position by reading the shift position of the sub-shift lever 15 with the sub-shift sensor 134. That is, 1.5 kg / cm 2 at extremely low speed and low speed, and 2.0 k at medium speed.
Feedback control is performed at g / cm @ 2 and at 2.3 kg / cm @ 2 at high speed. The low-pressure stop pressure can be changed with an external communication device. The feedback control of the clutch pressure is performed after a certain time after the control output. FIG. 13 shows this low pressure holding state. B1 indicates low pressure holding when the shift position of the sub-shift lever 15 is medium speed. B2 indicates the low pressure holding when the shift position of the auxiliary transmission lever 15 is extremely low and low. C indicates low pressure holding when the shift position of the sub-shift lever 15 is high. As described above, since the pressure is maintained at a low pressure, the transition from the stopped state to the traveling state can be performed quickly.

As described above, since the low pressure holding pressure is increased as the sub-shift is performed at a higher speed, the vehicle can start smoothly when starting again.
In the feedback control, when pressure sensors are mounted on both the forward side and the reverse side of the forward / reverse clutch 48, the feedback control is performed by each pressure sensor, and either one (reverse side) has no pressure sensor. In this case, the feedback control may be performed using the latest value of the pressure sensor on the other side (forward side). Thereby, it becomes an inexpensive structure.

  If the vehicle speed exceeds the predetermined speed (3 km / h) when the brake pedal is depressed, the first high / low clutch 24 and the second high / low clutch 25 are disconnected for a predetermined time (about 1 second). By doing so, the power from the engine is cut off for 1 second, so that deceleration can be started smoothly. The first high / low clutch 24 and the second high / low clutch 25 are kept disconnected until the vehicle speed becomes (3 km / h) or less, not limited to one second.

When the brake pedal is depressed, if the main gear shift is 5th or higher, it is possible to smoothly decelerate and stop by automatically setting it to 4th. At this time, since the position of the main transmission lever 14 is 5th speed or higher, when the accelerator pedal 18 is depressed and the indicated value becomes 1350 rpm or higher (
The travel is started again), and the speed is returned to the original speed change position (position of the main speed change lever 14) shifted one step. However, the speed increase will be canceled if there is an auxiliary speed change operation. When the position of the main shift lever 14 matches the position of the main shift stage in the transmission, the speed increase is released, and thereafter the shift to the shift by the shift of the main shift lever 14 is performed. Further, when the main transmission lever 14 is operated until the position of the main transmission lever 14 and the position of the main transmission gear stage in the mission coincide with each other, the main transmission gear stage in the mission is set so that the gear position is reached. However, the speed may be increased or decreased or the speed may be changed at a stroke. At this time, the connection of the hydraulic clutch for the main speed change is slowed to prevent a speed change shock.

  When the vehicle is stopped by stepping on the brake pedal in the no-clutch brake operation state, the forward / reverse clutch 48 pressure increase after the foot is released from the brake pedal is configured to vary the pressure increase curve at the position of the sub-shift (FIG. 13). At this time, when the accelerator pedal is operated, the pressure is boosted by another boosting curve. The boosting curve when the foot is released from the brake pedal and the boosting curve when the accelerator pedal 18 is depressed are compared, and the higher boosting curve is selected to boost the pressure.

  When the brake pedal is depressed and the vehicle is stopped with the no-clutch brake activated, if the clutch pedal 1002 is depressed (the command pressure of the forward / reverse clutch 48 is zero to cut off the power), the command pressure is lower. That is, the command pressure of the clutch pedal 1002 is selected.

  In addition, as described above, the boost curve when the foot is released from the brake pedal and the boost curve when the accelerator pedal 18 is depressed are compared, and the higher boost curve is selected to boost the pressure. When there is an operation of depressing the clutch pedal 1002 (the command pressure of the forward / reverse clutch 48 is zero in order to cut power), the command pressure of the clutch pedal 1002, that is, the command pressure of the clutch pedal 1002 is selected. Since the clutch pedal sensor 121 of the clutch pedal 1002 is a position sensor, the command pressure to the forward / reverse clutch 48 can be changed linearly in accordance with the amount of depression. Even in this case, the one with the lower command pressure is selected and output.

  In the no-clutch brake operation state, the first high / low clutch 24 and the second high / low clutch 25 are not operated and the forward / reverse clutch 48 is disengaged even if the clutch pedal sensor 121 is turned on, that is, the clutch pedal is depressed. Let

  Even if the no-clutch switch 126 is pressed and the brake coupling rod 94 is removed even if the no-clutch brake is in operation, the no-clutch brake operation is interrupted and the forward / reverse clutch 48 is not in the low-pressure stop state.

  As shown in FIG. 10, when the right brake pedal 19R or the left brake pedal 19L is depressed in the no-clutch brake operating state, the forward / reverse clutch 48 is kept in the low pressure holding state, but when the vehicle speed exceeds 3 km / h. , Turn off the connected first high / low clutch 24 or second high / low clutch 25 for 1 second, and if the vehicle speed still exceeds 3 km / h, keep the clutch disengaged until the speed drops below that. To cut off.

  When the clutch pedal sensor 121, the right brake sensor 123R, and the left brake sensor 123L are all on or off and the no clutch switch 126 is turned off, the no clutch brake operating state is released.

  As shown in FIG. 11, when the travel shift position of the shift lever is 5th speed or higher and no clutch is stopped, the gear position is automatically changed to 4th speed. Further, when the travel starts when the travel shift position of the shift lever is 5th speed or higher, as shown in FIG. 12, when the engine speed reaches 1350 rpm, the speed is increased step by step and returned to the original speed. Then, the automatic shift is canceled when the original shift stage is restored. If the sub-shift is changed at that time, the automatic return is stopped.

  When the right brake sensor 123R and the left brake sensor 123L are both off and the brake connection sensor 125 is turned off, the no-clutch brake operation state is interrupted, but either the right brake sensor 123R or the left brake sensor 123L is on, that is, stopped. Even if the brake connection sensor 125 is turned on, the no clutch brake operation state is not released. However, when the right brake sensor 123R and the left brake sensor 123L are turned off with the brake connection sensor 125 turned off, the no-clutch brake operation state is released.

The nokura indicator lamp 146 and the low pressure warning lamp 147 shown in FIG. 6 are lit under the following conditions.
The no-kura indicator lamp 146 is turned on when the no-clutch brake is operated, and is turned off when the no-clutch brake is released or interrupted.

  The low-pressure warning lamp 147 lights up or flashes normally when the no-clutch brake is stopped in the no-clutch brake operation state, and when this state exceeds 2 minutes, it flashes rapidly to warn the user not to continue the no-clutch brake for a long time. It turns off in the state.

  FIG. 13 is a pressure increase pattern of the forward / reverse clutch 48. A is a case where the accelerator pedal 18 is depressed to start, or a case where the accelerator pedal 18 is depressed when starting from the brake stop state, and the vehicle starts moving. Use full pressure. B1 is a case where the brake is released from the brake stop state to return to traveling when the shift position of the sub-shift lever 15 is medium speed. B2 is a case in which the brake is released from the brake stop state to return to traveling when the shift position of the auxiliary transmission lever 15 is extremely low and low. C is a case where the brake is released from the brake stop state to return to traveling when the shift position of the auxiliary transmission lever 15 is high. When the accelerator pedal 18 is stepped on the way to return to the full pressure by releasing the brake, the pressure goes up to the pressure increasing pattern A and the pressure is rapidly increased. As a result, the pressure is increased with a higher pressure increasing pattern as the sub-shift is faster, so that the target speed can be reached quickly.

  When the accelerator pedal 18 is depressed, the A boosting pattern is compared with the B1 boosting pattern, the B2 boosting pattern, or the C boosting pattern, and the higher pressure is selected and boosted. It is configured.

  If the accelerator pedal 18 is depressed immediately after the brake pedal depression operation is released, the boost curve A1 is selected. However, if a certain amount of time has passed after the brake pedal depression operation is released, the B1 boost pattern or Since the boosting pattern of B2 or the boosting pattern of C is advanced, the boosting pattern of B1 or the boosting pattern of B2 or the boosting pattern of C is higher than the boosting pattern of A. Therefore, the boosting pattern of B1 Alternatively, the pressure of the boosting pattern of B2 or the boosting pattern of C is selected. However, when the A boost pattern increases with time, the pressure of the A boost pattern is selected and output.

  The boost pattern and the low pressure holding pressure (low pressure operating pressure) are changed according to the position of the sub-shift, but may be changed according to the position of the main shift. Further, it may be changed by a combination of the sub-shift and the main shift. Also in this case, the higher the speed, the higher the pressure.

  The main speed change lever 14 is configured to be operable in a straight line from the first speed to the eighth speed from the neutral position toward the front of the machine body. Further, when the main shift lever 14 is moved from the neutral position to the “automatic shift position” on the rear side of the machine body, the automatic shift is started. The main shift lever 14 is moved to the “automatic shift position” once in the lateral direction (rightward or leftward) and then moved backward. This is to prevent erroneous operation.

  When the main shift lever 14 is set to the “automatic shift position”, the main shift in the mission is set to the fourth speed. Press the clutch pedal to select the sub-shift. The forward / reverse lever 10 is set to the forward position. Thereafter, when the foot is released from the clutch pedal, the vehicle starts running. As the accelerator pedal 18 is depressed, the vehicle speed increases as the engine rotates. As the engine speed increases, the main shift in the mission increases. When the depression of the accelerator pedal 18 is reduced, the main shift is decelerated. When the clutch pedal 1002 is depressed and the brake pedal is depressed to stop the aircraft, the main shift returns to the fourth speed. In addition, when the forward / reverse lever 10 is moved backward before starting or running, the automatic transmission function is temporarily interrupted, and the main transmission maintains the fourth speed.

2 Front wheel 3 Rear wheel 5 Engine 14 Main transmission lever 15 Sub transmission lever 18 Accelerator pedal 19L Left brake pedal 19R Right brake pedal 48 Forward / reverse clutch 135 Brake 146 Notifying means (nocler indicator)
1002 Clutch pedal

Claims (4)

  A forward / reverse clutch (48) for switching between forward / reverse and neutral is provided in the power transmission path from the engine (5) to the traveling device such as the front wheels (2) and the rear wheels (3), and brake pedals (19L), (19R) The brake (135) is actuated on the travel device in accordance with the depression, and the connection operating pressure of the forward / reverse clutch (48) is reduced, and the forward / reverse clutch (48) is set to a predetermined low pressure when the vehicle is in a travel stop state. A tractor characterized in that it is held at a stop operating pressure, and the stop operating pressure of the forward / reverse clutch (48) is set higher as the shift position of the auxiliary transmission lever (15) is higher.   The power of the forward / reverse clutch (48) can be turned on and off by operating the clutch pedal (1002), and the airframe can be operated only by operating the brake pedal (19L) and (19R) without stepping on the clutch pedal (1002). The tractor according to claim 1, further comprising an informing means (146) for informing a state where the vehicle can be stopped.   When the brake pedals (19L) and (19R) are released, the pressure increase rate at which the connection operating pressure of the forward / reverse clutch (48) is returned to the full pressure is increased as the shift position of the auxiliary transmission lever (15) is higher. The tractor according to claim 1, wherein the tractor is set as follows.   When the accelerator pedal (18) is depressed after the brake pedals (19L) and (19R) are released, the pressure increases higher than the pressure increase rate when the brake pedals (19L) and (19R) are released. The tractor according to any one of claims 1 to 3, wherein the stop operating pressure is returned to the connection operating pressure of the total pressure at a rate.

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