JP2010106960A - Travel transmission device for tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To diminish shocks at a travel start time or a travel stop time in the travel transmission device of a working vehicle to stop the travel by putting the transmission, which is arranged in the power transmission path to a travel gear, in a double mating condition. <P>SOLUTION: The power transmission path to the travel gear A from the engine 2 sequentially includes a main clutch B, a multiple gear transmission device C, and a sub-clutch D in the travel transmission device of a tractor, and when the transmission device of the shift handling tool E is less than a predetermined transmission step F or less, disengaging the main clutch B causes, the multiple gear transmission device C to be put in a double mating condition. Further, when the running speed of the travel gear A is detected and the detected running speed is a predetermined speed G or more, disengaging the sub-clutch D in all the transmission positions of the transmission shift handling tools E causes multiple gear transmission devices C not to be put in the double mating condition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a traveling transmission device for a work vehicle having a friction multi-plate transmission clutch as a main clutch and a transmission capable of shifting in multiple stages in a transmission case that transmits engine power to the traveling device.

  In the work vehicle, by operating the transmission clutch to the transmission cut-off side, the power transmission to the traveling device can be cut off and the running can be stopped. However, in the friction multi-plate type transmission clutch, this is the transmission cut-off side. There are few situations where the engine power is completely cut off even if the engine is operated, the so-called friction plate rotation phenomenon occurs, the engine power is gradually transmitted from the transmission clutch to the lower side, and the aircraft slowly A moving phenomenon may occur.

As a means for preventing such a phenomenon that the friction plate rotates when the transmission clutch is disconnected, as described in Japanese Patent No. 3370231, when the transmission clutch is operated to the transmission disconnection side, In the transmission, a plurality of transmissions having different transmission ratios are automatically operated in a transmission state, that is, a double-engaged state, and the power transmission is locked.
Japanese Patent No. 3370231

  When the transmission clutch is operated to the transmission cut-off side and the transmission is in the double-engaged state, the power transmission to the traveling device is completely locked, causing the body to move slowly along with the friction plate Will not occur, but you will be shocked by a sudden stoppage.

  Therefore, the present invention provides a shock transmission at the start or stop of a travel in a travel transmission device of a work vehicle in which a transmission provided on a power transmission path to the travel device is double-engaged to stop the travel. It is an issue to reduce.

The problems of the present invention are solved by the following technical means.
The invention according to claim 1 is a tractor comprising a main clutch (B), a multi-stage gear transmission (C), and a sub-clutch (D) as a power transmission path from the engine (2) to the traveling device (A). In the traveling transmission device, when the main clutch (B) is disengaged when the shift position of the transmission operating tool (E) is equal to or lower than the predetermined shift speed (F), the multi-stage gear transmission (C) should be brought into a double-engaged state. The tractor travel transmission device is characterized by being configured.

  With this configuration, the multi-stage gear transmission C is in the double-engaged state only when the speed change position of the speed change tool E is equal to or lower than the predetermined speed F. Therefore, when the main clutch B is engaged at the predetermined speed F or higher and the engine is started. There is no shock due to the release of double biting, and since the start speed is low below the predetermined speed F, there is almost no shock due to the release of double biting.

  According to a second aspect of the present invention, the traveling speed of the traveling device (A) is detected, and when the traveling speed is equal to or higher than the predetermined speed (G), the sub-clutch is operated at all the shifting positions of the transmission operating tool (E). The tractor travel transmission device according to claim 1, wherein the multi-stage gear transmission (C) is not double-engaged when (D) is turned off.

  With this configuration, when the traveling speed is equal to or higher than the predetermined speed G, the multistage gear transmission C can be stopped without a sudden stop shock due to the double-engagement state. Even in the double-engaged state, there is no feeling of stop shock, and by disengaging the sub-clutch D, the driving of the traveling device A due to the rotation of the main clutch B can be turned off to completely stop.

  According to the first aspect of the present invention, since the multi-stage gear transmission C is in the double-engaged state only when the speed change position of the speed change tool E is equal to or lower than the predetermined speed F, the speed change position of the speed change tool E is set to the predetermined speed. There is an effect that there is no shock due to the release of double biting when starting at F or higher.

  Further, according to the invention described in claim 2, since the double-engagement state does not occur while the traveling speed is higher than the predetermined speed G, there is an effect that a stop shock is not felt when the traveling is stopped. is there.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a tractor 1 as a working machine in which the present invention is implemented.
The tractor 1 has an engine 2 mounted in a bonnet at the front of the airframe, transmits the rotational power of the engine 2 to a transmission in the transmission case 3, and the rotational power reduced by the transmission is transmitted to the front wheels 4 and the rear wheels 5. To tell. The area around the cockpit 6 on the fuselage is covered with a cabin 7. This engine 2 is a common rail type diesel engine, and is controlled so that the cell motor is rotated until a complete explosion occurs and rotation is stabilized when the engine key is turned once at the start.

  As shown in FIGS. 2 and 3, a steering handle 8 is erected on the front side of the cockpit 6 inside the cabin 7, and a forward / reverse lever 9 is provided on the lower right side thereof. On the left side of the cockpit 6, a parking brake lever 10 and a first PTO transmission lever 11 and a second PTO transmission lever 12 for shifting the PTO shaft that outputs power to the work implement are arranged.

  The lower floor of the steering handle 8 is provided with a left brake pedal 56 that brakes the left and right front and rear wheels 4 and 5, a right brake pedal 57, and an all brake pedal 58 that brakes all the wheels at once. An accelerator pedal 13 is provided for controlling the rotation. This accelerator pedal 13 is used to adjust the traveling speed.

  When the left brake pedal 56 and the right brake pedal 57 are depressed simultaneously, the brake is applied and the main gear shift stage is shifted to the low speed side to cause the engine brake to act. Further, when the left brake pedal 56 and the right brake pedal 57 are depressed more than a predetermined limit depression amount, the engine speed is decreased. At this time, if the left brake pedal 56 and the right brake pedal 57 are depressed and restored, the engine rotation is restored, and the power transmission to the front and rear wheels 4 and 5 and the power transmission to the PTO output shaft are restored. Try to release the brake.

  A front panel 14 on which a meter panel 72 (FIG. 5) for displaying the traveling speed and an operation panel 73 (FIG. 5) for displaying the usage status of the work implement are provided on the front side of the steering handle 8.

  When the throttle lever 15 is erected on the right side of the cockpit 6 and is tilted forward from the foremost idling position, the rotation of the engine 2 increases. The throttle lever 15 is used to set the engine speed during operation. Reference numeral 16 denotes a seesaw-type first engine rotation storage switch. When the switch is tilted upward, the first stored rotational speed is obtained. When the switch is tilted downward, the second stored rotational speed is obtained. When the finger is released, the position returns to the neutral position. Reference numeral 17 denotes a seesaw-type second engine rotation storage switch. When the switch is tilted upward, the rotational speed increases. When the switch is tilted downward, the rotational speed decreases, and the rotational speed when the switch is released is stored. The rotation speed of the engine 2 is set by turning the first engine rotation storage switch 16 upward or downward and tilting the second engine rotation storage switch 17 upward or downward to increase or decrease the rotation speed. , 17 is released, the speed at that time is stored as the set speed of the first engine speed storage switch 16.

  Next to the throttle lever 15, an auxiliary transmission lever 18 is erected. The sub-shift lever 18 has three speeds of low speed, medium speed, and high speed and a shift position for traveling on the road. -Shifts at a high speed and the main shift can be shifted to eight stages, and at the road running position, the main gear can be shifted using a gear stage with three or more speeds at a high speed and the speed is suitable for road driving.

  The main shift is a combination of high and low two-speed shifts by hydraulic control, as in the case of four-speed shifts by hydraulic control, and has a total of eight shift stages. The average vehicle speed by these shift stages is the low / medium of the sub-shift lever 18. Combined with high speed and high speed, there are a total of 24 shift stages. The shift stage of the main shift is changed by a travel shift increase switch 33 and a travel shift decrease switch 34 which will be described later.

  Reference numerals 19 and 20 are sub-control levers for taking out external hydraulic pressure, and are used when hydraulic oil is supplied to a hydraulic cylinder or the like of the working machine. 21 and 22 are spare sub-control lever mounting grooves. 23 is a draft ratio adjustment dial, which turns to the left when turned to the position side, reduces the amount of change in the working machine's lifting with respect to the load, reduces the tilling depth, and conversely turns to the right to become the draft side. The amount of change in the lifting and lowering of the work implement with respect to increases the plowing depth.

  Reference numeral 24 denotes a lifting adjustment dial. When the dial 24 is turned counterclockwise, the rising height of the three-point link is lowered. Depending on the working machine, when it is raised to the highest level, when it hits the tractor body or when it is more efficient to continue the work if it is not raised too much, adjustment is made with this raising adjustment dial 24. Reference numeral 25 denotes an inclination adjustment dial. When the dial is turned counterclockwise, the work implement is raised to the right, and conversely, when the knob is turned right, the work implement is lowered.

  26 is a four-WD changeover switch, which has a travel loader, a super full turn, and a two-WD turn position, and the travel loader automatically switches to four WD when it becomes a muddy, steep hill or uneven road, usually with two WD, Even if the brake is applied or stopped during operation, the state becomes four WD. Two-WD is a rear-wheel two-wheel drive, and four-WD is a front-rear four-wheel drive. In the super full turn, the speed of the front wheel is increased by turning at the 4WD, and quick turning is possible, and in the 2WD turn, the driving of the front wheel is removed by turning at the 4WD and the rear wheel is turned by one brake. Quick and smooth turn in hard fields.

  Reference numeral 27 denotes a horizontal cylinder raising / lowering switch which can move the horizontal cylinder of the three-point link and is used for attaching / detaching the work machine. Reference numeral 28 denotes a PTO switch. When the switch is pushed and turned to the right, the PTO clutch is engaged. Reference numeral 29 denotes a PTO automatic switch, which is manually operated when turned to the left and the PTO shaft is always rotated when the PTO clutch is engaged, and is automatically turned when turned to the right and stops rotating when the travel clutch is stepped on or the three-point link is raised. This PTO automatic switch 29 is mainly used during paddy field work.

Reference numeral 30 denotes a diff lock switch. When it is pushed outward once, it becomes diff lock, and when it is pushed outward again, the diff lock is released. It cannot be pushed inward, but switches each time it is pushed outward.
31 is a working machine raising / lowering lever, the front side descends and the rear side rises. Reference numeral 32 denotes a work implement lifting switch, which is raised to the uppermost position set by the raising adjustment dial 24 by pushing the rear side once, and lowered to the position set by the work implement raising / lowering lever 31 when the front side is pushed once.

  Reference numeral 33 denotes a travel shift increase switch, 34 a travel shift decrease switch, and a switch for setting a start shift stage. Each time the travel shift increase switch 33 is pressed once, the start shift stage is shifted up, and the travel shift decrease switch 34 is set to 1. Every time the switch is pressed, the starting gear is shifted down. The travel shift increase switch 33 and the travel shift decrease switch 34 change the start shift stage up and down in the same manner when the sub-shift lever 18 is driven on the road and the sub-shift is at a high speed and the main shift is at the third speed. To do.

Reference numeral 36 denotes a switch box. When the lid is opened, various adjustment switches shown in FIG. 3 are arranged.
In the switch box 36 shown in FIG. 3, reference numeral 37 denotes a work machine ascent / descent monitor lamp which is lit and displayed when the work machine is raised and lowered. Reference numeral 38 denotes an AT shift sensitivity dial which changes the sensitivity for increasing or decreasing the vehicle speed when the AT shift work switch 42 is pressed to perform automatic shifting.

  No. 39 is a descent speed dial that adjusts the descent speed of the work implement. When it is turned to the right, the work implement descends quickly, so it is used for light work implements. Conversely, turning it counterclockwise lowers the work implement slowly, so it is heavy. Used for work machines.

Reference numeral 40 denotes a travel brake adjustment dial, which adjusts the degree of application of the turning brake that acts when the auto brake on / off switch 48 is turned on.
The AT shift road switch 41 automatically shifts the main shift when traveling on the road, that is, the sub-shift is at a high speed, and the AT shift work switch 42 automatically shifts the main shift when traveling, that is, the sub-shift is at the middle / low speed, When the switch is turned on, the main shift is automatically shifted to the shift stage that has been used the longest last time according to the shift position of the sub shift lever 18, and when it is turned off, it is arbitrarily set according to the shift position of the sub shift lever 18 The gear shifts to the main gear.

  43 is a connection sensitivity shift switch for the main shift, which changes the connection feeling when the main shift is shifted, and when the switch is turned on, the monitor is turned on and a gentle shift is performed. When the connection sensitivity shift switch 43 is turned off and a traction system such as a plow is operated, the shift connection time of the main transmission is shortened, and the operation can be performed lightly.

  44 is a connection sensitivity PTO switch, which has a rotary, pasture 1 and pasture 2; when it is set to rotary, the connection of PTO becomes faster, and the rotary immediately turns with a rotational force that does not lose the resistance of soil. When it is set to 2, the connection of PTO becomes loose and it is used with pasture work machines and snow blowers.

45 is a horizontal sensitivity switch, and the operation sensitivity of the automatic horizontal control device of the work machine changes. When the switch is pressed, the movement of the automatic horizontal control becomes slow, and when the switch is pressed again, it returns to the original state.
46 is a backup on / off switch, and when it is turned on, the work machine is automatically raised when the vehicle moves backward. 47 is an auto lift on / off switch, and when the handle is turned on, the work machine is automatically raised. 48 is an auto brake on / off switch, and when it is turned on and the handle is turned, only the rear wheel inside the turn is automatically braked.

  49 is a horizontal changeover switch. When the level is automatically leveled, the level of the work machine is automatically maintained by the level sensor. When the level is set manually, the tilt adjustment dial 25 can be adjusted. Is always kept parallel, and when tilted, the three-point link is held at a constant tilt angle with respect to the ground.

Reference numeral 50 denotes a 3P changeover switch, which performs control changeover selection based on the lift cylinder mounting position to the three-point link.
Reference numeral 51 denotes an auto accelerator switch. When the work machine is raised in the on state, the engine speed decreases to 1700 rpm.

FIG. 4 is a diagram showing a driving force transmission mechanism, and a power transmission configuration from the engine 2 to the front wheels 4 and the rear wheels 5 will be described.
A first gear 111 is fixed to an input shaft 110 directly connected to an output shaft of the engine 2 and a forward / reverse switching clutch 101 is mounted.

  One second gear 112 of the forward / reverse switching clutch 101 meshes with a third gear 114 fixed to the first transmission shaft 113 and decelerates, and the other fourth gear 115 of the forward / reverse switching clutch 101 is connected via a counter gear 117. The power is transmitted in reverse by meshing with the fifth gear 118 fixed to the first transmission shaft 113. That is, when the forward / reverse switching clutch 101 is placed (connected) on the second gear 112 side, the rotation of the input shaft 110 is transmitted in the reverse direction to the first transmission shaft 113, and when it is placed on the fourth gear 115 side, The rotation is transmitted to the first transmission shaft 113 in the forward direction, and the neutral state away from both the second gear 112 and the fourth gear 115 is the main clutch disengaged state where the power transmission is cut off. The clutch disengaged state can be maintained. That is, the forward / reverse switching clutch 101 operated by automatic control or the forward / reverse lever 9 functions as a main clutch.

  A first speed / three-speed switching first transmission clutch 102 and a second speed / four-speed switching second transmission clutch 103 are mounted on the first transmission shaft 113 on the lower transmission side of the forward / reverse switching clutch 101. That is, the first speed / third speed switching first transmission clutch 102 and the second speed / fourth speed switching second transmission clutch 103 function as the multi-stage gear transmission clutch of the present invention. 34 is used to change the speed.

  The first clutch gear 120 and the second clutch gear 122 of the first transmission clutch 102 are engaged with a third clutch gear 121 and a fourth clutch gear 123 fixed to the second counter shaft 119, and are decelerated for the first speed or for the third speed. The rotation of the first transmission shaft 113 is transmitted to the second counter shaft 119 with a slight increase in speed. Further, the fifth clutch gear 124 and the sixth clutch gear 126 of the second transmission clutch 103 are engaged with the seventh clutch gear 125 and the eighth clutch gear 127 fixed to the second counter shaft 119, and are slightly increased for the second speed. The speed of the first speed change shaft 113 is transmitted to the second countershaft 119 by greatly increasing the speed for the fourth speed.

  In the present invention, the double-engaged state is, for example, a state in which the first speed / third speed switching first speed change clutch 102 is set to the first speed and the second speed / fourth speed speed change second speed change clutch 103 is simultaneously set to the second speed. Thus, the state where the rotation of the second counter shaft 119 is completely locked and the rotation is not transmitted first is controlled by the traveling system controller 87 under the operating conditions described later.

  A third counter shaft 129 is connected to the lower transmission side of the second counter shaft 119 by a coupling 128 to transmit the rotation as it is. A small gear 130 and a large gear 131 are fixed to the third counter shaft 129. The small gear 130 and the large gear 131 are engaged with the clutch large gear 133 and the clutch small gear 134 of the high / low speed switching clutch 107 mounted on the second transmission shaft 132, respectively, and the third counter shaft 129 rotates at a high speed or a low speed. It is transmitted to the two speed change shaft 132. A high / low speed switching clutch 107 that is automatically controlled or operated by a high / low speed shift lever 109 functions as a sub-clutch of the present invention.

  The sixth gear 136 is fixed to the lower transmission side end portion of the second transmission shaft 132, and the sixth gear 136 and the large gear portion 138 of the large and small gear 152 pivotally supported by the third drive shaft 143 are engaged with each other. Is decelerating.

  The small gear portion 139 of the large and small gears 152 meshes with the seventh gear 137 of the double auxiliary transmission clutch 135 that is pivotally supported by the bevel gear shaft 142 and is transmitted at a reduced speed. Further, the eighth gear 141 provided integrally with the seventh gear 137 is engaged with the second large gear 144 fixed to the fifth counter shaft 216 for transmission at a reduced speed.

  A second small gear 145 is further fixed to the fifth counter shaft 216, and the second small gear 145 meshes with the third large gear 140 of the bevel gear shaft 142 to further reduce the transmission. Accordingly, the rotation of the second transmission shaft 132 is the sixth gear 136 → the large gear portion 138 → the small gear portion 139 → the seventh gear 137 → the eighth gear 141 → the second large gear 144 → the second small gear 145 → the third large gear. The gear 140 is transmitted while being sequentially decelerated.

  The first shifter 217 and the second shifter 218 of the double sub-shift clutch 135 operated by the auxiliary transmission lever 18 are slidably engaged with the bevel gear shaft 142 in the axial direction, and the first shifter 217 is engaged with the seventh gear 137. When the second shifter 218 slides and engages with the eighth gear 141, the rotation of the eighth gear 141 is transmitted to the bevel gear shaft 142. Accordingly, the bevel gear shaft 142 is sequentially decelerated and rotates at a low speed.

  The rotation of the bevel gear shaft 142 is transmitted to the differential gear 219 via the first bevel gear 148 and the second bevel gear 149, and is transmitted from the differential gear 219 to the rear wheel 5 via the axle 150 and the planetary gear 151.

  To summarize the above description, the rotation of the input shaft 110 is first switched to forward rotation or reverse rotation by the forward / reverse switching clutch 101, and the first speed / three-speed switching first shift clutch 102 and the second / fourth-speed switching first gear 102 are switched. The speed is changed from the first speed to the fourth speed by the two speed clutch 103, the speed is changed to the high speed and the low speed by the high / low speed switching clutch 107, and the high speed, the middle speed and the low speed are further increased by the double sub-shift clutch 135. And is transmitted to the bevel gear shaft 142. That is, the rotation of the input shaft 110 is shifted to 4 × 2 × 3 = 24 speeds and transmitted to the axle 150.

  For driving force transmission to the front wheel 4, the ninth gear 147 is fixed to the bevel gear shaft 142, the ninth gear 147 is meshed with the relay gear 190, and further meshed with the tenth gear 146 fixed to the third drive shaft 143. The third drive shaft 143 is driven. The third drive shaft 143 is connected by a second coupling 170 to a transmission shaft 160 to which a front wheel speed increasing clutch 163 is attached. The eleventh gear 167 and the twelfth gear 168 of the front wheel speed increasing clutch 163 are engaged with the thirteenth gear 165 and the fourteenth gear 166 fixed to the seventh counter shaft 164, so that the front wheel speed increases from the normal front wheel drive. To switch to. When the front wheel acceleration clutch 163 is neutral, the driving of the front wheels 4 is cut off and only the rear wheels are driven.

  The seventh counter shaft 164 is connected to the front wheel drive shaft 169 by a third coupling 191, and is further connected to the front wheel drive bevel shaft 171 by a fourth coupling 192, an extension shaft 194 and a fifth coupling 193.

  The power of the front wheel drive bevel shaft 171 is as follows: front first bevel gear 172, front second bevel gear 173, front differential gear 174, front third bevel gear 175, front fourth bevel gear 176, vertical shaft 177, front fifth bevel gear 178, front sixth The front wheel 4 is driven via the bevel gear 179 and the front planetary gear 180.

Next, the flow of the control signal will be described with reference to the control block diagram of FIG.
First, the engine controller 60 receives the exhaust temperature from the engine exhaust temperature sensor 61, the engine speed from the engine rotation sensor 62, the engine lubricating oil pressure from the engine oil pressure sensor 63, and the engine water temperature sensor 64. The temperature of the cooling water enters, the pressure of the common rail enters from the rail pressure sensor 55, a drive signal is output to the fuel high-pressure pump 66, and a fuel supply adjustment control signal is output to the high-pressure injector 65.

  Next, the work implement elevating controller 67 includes an operation signal of the work implement elevating sensor 59 provided on the work implement elevating lever 31, an elevating signal of the lift arm sensor 68, a raising position restriction signal of the raising adjustment dial 24, and a lowering speed dial 39. A descent speed setting signal is input, and a work implement elevating signal is output to the main ascending solenoid 69 and the main descent solenoid 70 to operate the work implement elevating cylinder 71.

  The engine controller 60, the work implement elevating controller 67, and a travel system controller 87, which will be described later, communicate with each other, and the engine panel, the elevating state of the work implement, the travel speed of the travel device, and the like are displayed on the meter panel 72. The operation position of each lever and pedal is displayed on the panel 73.

  The travel system controller 87 receives the clutch engagement signal, that is, the gear position of the multi-stage gear transmission C, from the shift 1 clutch pressure sensor 74, the shift 2 clutch pressure sensor 75, the shift 3 clutch pressure sensor 76, and the shift 4 clutch pressure sensor 77, The shift position of the sub-clutch D is input from the high-speed clutch pressure sensor 78 and the low-speed clutch pressure sensor 79, and forward / neutral / reverse of the main clutch B is input from the forward clutch pressure sensor 80 and the reverse clutch pressure sensor 81, and the forward / backward lever A shift operation position signal is input from the operation position sensor 82 and the auxiliary shift lever operation position sensor 83, a mission oil temperature is input from the mission oil temperature sensor 85, and a brake pedal depression signal is input from the brake pedal operation position sensor 86. The accelerator mode designation switch 84 A front wheel drive angle switch 100 and a front wheel drive on / off signal from a front wheel drive changeover switch 106, and a rear wheel drive shaft rotation sensor 104 and a front wheel drive shaft. The rotational speed is input from the rotation sensor 105, the set gear stage signal is input from the traveling shift increase switch 33 and the traveling shift decrease switch 34, and the upper and lower limit rotational speeds of the engine are determined from the accelerator upper limit change switch 52 and the accelerator lower limit change switch 53. Then, an accelerator instruction signal is input from the accelerator sensor 54 of the throttle lever 15, and a check signal is input from the check switch 99.

Further, an ON / OFF signal is input to the traveling system controller 87 from the AT shift road switch 41 and the AT shift work switch 42.
As for the output from the travel system controller 87, the switching signal of the forward / reverse switching clutch 101 is output to the forward / reverse switching solenoid 88, and the hydraulic relief pressure adjustment signal for driving the forward / reverse switching solenoid 88 is output to the linear boost solenoid 89. The clutch engagement shock is reduced, an on / off signal is output to the clutch solenoid 90, and the first to third switching solenoid 91 of the hydraulic cylinder that drives the first speed / three-speed switching first shift clutch 102 is driven to the first or third speed. A high-speed input signal is output, and a hydraulic relief pressure adjustment signal for driving the first-speed / third-speed clutch is output to the shift 1-3 boost solenoid 92 to reduce the shock of clutch connection, and for two-speed / four-speed switching A second or fourth speed on signal is output to the shift 2-4 switching solenoid 93 of the hydraulic cylinder that drives the second shift clutch 103, and the shift 2-4 boost solenoid A high-speed clutch switching solenoid 95 that operates a hydraulic cylinder that drives the high / low-speed switching clutch 107 by outputting a relief pressure adjustment signal for hydraulic pressure that drives the second / fourth speed clutch to the id 94 to reduce the shock of clutch connection; The low speed clutch switching solenoid 96 outputs a high speed clutch input signal and a low speed clutch input signal.

  Further, the traveling system controller 87 outputs a front wheel drive switching clutch switching signal to the front wheel acceleration 4WD solenoid 97 and the front wheel constant speed 4WD solenoid 98 of the hydraulic cylinder that drives the front wheel acceleration clutch 163.

FIG. 6 shows a flowchart of control for automatically braking the rotation of the transmission shaft by double-engaging the multi-stage gear transmission C.
When the operation of disengaging the main clutch B with the forward / reverse lever 9 being neutral is performed (S1), it is first determined whether the traveling speed is equal to or less than a predetermined speed G (0.5 km / h) (S2). The clutch B is disengaged (S6), a time count of 6 seconds is performed (S7), and the process proceeds to step S10.
If the traveling speed is equal to or lower than the predetermined speed G, the shift position is next to the predetermined shift speed F (medium speed of four speeds (the multiple sub-transmission clutch 135 is medium speed, the sub-clutch D is low speed and the multi-speed gear transmission C is 4th speed state))), it is determined whether it is on the low speed side (S3). If it is on the low speed side, the main clutch B is disengaged (S4), the main transmission clutch C is double-engaged (S5), and step S10 Migrate to

  If the shift position is higher than the predetermined shift stage F, the main clutch B is disengaged (S8), and it is determined whether the oil temperature in the transmission case 3 is 10 ° C. or less (S9). The main shift clutch C is double-engaged, and if it is the above, the process proceeds to step S10.

  In step 10, the sub-clutch D is disengaged and it is determined again whether the traveling speed is 0.5 km / h or less (S11). If it is the following, the sub-clutch D is disengaged (S12), and the traveling is stopped (S13). Return. If the traveling speed is 0.5 km / h or more, the sub-clutch D is disengaged.

FIG. 7 is a flowchart for correcting pressure values detected by pressure sensors such as the shift 1 clutch pressure sensor 74 and the shift 2 clutch pressure sensor 75.
First, it is determined whether or not the correction mode switch has been pressed when the oil temperature is in the range of 30 ° C. to 70 ° C. (S20). If the condition is satisfied, an appropriate set value a is set in the resolution DA and the pressure is set to the theoretical pressure. P0 is set (S21).
Then, the theoretical pressure P0 is compared with the actual pressure Pn (S22). If the theoretical pressure P0 and the actual pressure Pn coincide with each other, the correction value is set to 0 (S27) and the process returns.

  If the theoretical pressure P0 is smaller than the actual pressure Pn, the correction value is set to -1 (S23), -1 is subtracted from the resolution DA and output (S24), and the theoretical pressure P0 is compared with the actual pressure Pn again (S25). The correction is repeated until the pressure P0 and the actual pressure Pn match, and if they match, the resolution DA is set as a correction value (S26) and the process returns.

  If the theoretical pressure P0 is greater than the actual pressure Pn, the correction value is incremented by 1 (S28), the resolution DA is incremented by 1 and output (S29), the theoretical pressure P0 is compared with the actual pressure Pn again (S30), and the theoretical pressure P0 The correction is repeated until the actual pressure Pn and the actual pressure Pn match, and if they match, the resolution DA is set as a correction value (S31) and the process returns.

FIG. 8 shows a relief valve used in the hydraulic circuit.
A pressure adjusting ball 155 is sandwiched between the tip of the plug 154 and the spring seat 156 between a plug 154 that is screwed into the body 153 from one end and an adjustment screw 159 that is screwed into the other end, and a spring 157 that presses the spring seat 156 is provided. A spring retainer 158 is provided, and the spring retainer 158 is received by an adjustment screw 159 via a ball 186. Inside the spring 157, a damper portion 185 is formed by a spring seat 156 and a spring retainer 158.

The oil hole 182 of the plug 154 has a small-diameter throttle hole 183 in the middle of reaching the pressure adjusting ball 155, thereby preventing chattering from occurring as a laminar flow of oil.
The pressure adjusting ball 155 is received by the hole portion of the spring seat 156. The inlet end surface 184 of the hole portion is a tapered surface inclined toward the hole direction, so that the pressure adjusting ball 155 is easily lifted by the flow of oil. .

The receiving ball 186 is fitted into the hole of the spring retainer 158, and the adjustment screw 159 side is received by the V hole 181 to prevent the spring 157 from falling and stabilize the receiving ball 186.
The spring seat 156, the spring 157, and the spring retainer 158 have outer diameter dimensions so that the spring seat 156, the spring retainer 158, and the body 153 can move smoothly without contacting the holes.

It is a whole side view of a tractor of a present Example. It is an expansion perspective view around the cockpit of a tractor. It is a front view of a switch box. It is a power transmission diagram of a mission case. It is a block diagram of control. It is a flowchart figure of control. It is a correction | amendment flowchart figure of a pressure detection value. It is sectional drawing of a relief valve.

Explanation of symbols

A traveling device (front wheel 4 and rear wheel 5)
B Main clutch (forward / reverse switching clutch 101)
C multi-stage gear transmission (first speed / three-speed switching first speed change clutch 102 and second speed / four speed speed change second speed clutch 103)
D Sub-clutch (High / low speed switching clutch 107)
E Gearshift operation tool (travel gearshift up switch 33, travel gearshift switch 34, and subshift lever 18)
F Predetermined gear position (medium speed four steps)
G Predetermined speed (0.5km / h)
2 Engine

Claims (2)

  In a tractor traveling transmission device in which a power transmission path from an engine (2) to a traveling device (A) is composed of a main clutch (B), a multi-stage gear transmission (C), and a sub-clutch (D) in sequence, A tractor characterized in that when the main clutch (B) is disengaged when the shift position of E) is equal to or lower than a predetermined shift speed (F), the multi-stage gear transmission (C) is brought into a double engagement state. Traveling transmission device.   When the traveling speed of the traveling device (A) is detected and the traveling speed is equal to or higher than the predetermined speed (G), the multi-stage is established when the sub-clutch (D) is disengaged at all shift positions of the transmission operation tool (E). The tractor travel transmission device according to claim 1, wherein the gear transmission (C) is configured not to be in a double-engaged state.

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