JP2009107456A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle which can be operated by an operator at proper engine speed, running speed and PTO speed of rotation by detecting the load state of an engine under working, and letting an operator know a current engine load state. <P>SOLUTION: The working vehicle calculates the engine speed and an engine load; determines the propriety of the engine speed based on the calculated engine load state; instructs the change of the engine speed to the proper engine speed when it is determined that the engine speed is not proper; and instructs shift to maintain the running speed of a vehicle body and the PTO speed of rotation at a state prior to the instruction of the change of the engine speed according to the engine speed whose change has been instructed. The working vehicle is provided with a control device which causes an engine speed change instruction means and a shift instruction means to perform shift instruction when the instructed engine speed is equal to or more than the prescribed engine speed and instructs the prescribed engine speed to the engine speed change instruction means when the engine speed is less than the prescribed engine speed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to work vehicles such as tractors and construction vehicles.

  When driving a machine with an engine, the output corresponding to the load cannot be obtained unless the engine speed is increased at high loads, but the fuel consumption is reduced by setting the engine speed low at medium to low loads. be able to. When performing farm work or the like with a tractor, an operator often sets operation conditions such as engine speed, traveling speed, and PTO speed so as to obtain target work accuracy and work efficiency. In that case, the operator sets the operating conditions sensuously and empirically from the sound of the engine, the color of the exhaust smoke, and the vibration state when the engine is operating, so it is not always possible to set appropriate operating conditions with low fuel consumption. It was.

Based on this background, the invention described in Japanese Patent Application Laid-Open No. 2006-125295 detects the tractor workload without relying on experience, and calculates the appropriate engine speed, running speed and PTO speed. A technique for controlling is disclosed.
In addition, the invention described in Japanese Patent Application Laid-Open No. 2006-123724 discloses a technique for detecting the work load of a tractor and calculating and instructing an appropriate engine speed, traveling speed stage and PTO speed stage with low fuel consumption. Has been.
JP 2006-125295 A JP 2006-123724 A

  In Patent Document 1, the engine load is calculated from the engine speed and the exhaust temperature of the engine, and whether or not the engine speed is appropriate is determined. If the engine speed is not appropriate, the engine speed is changed to an appropriate engine speed. Along with this, there is disclosed a technique for performing shift control so that the traveling speed of the airframe and the PTO rotational speed do not change.

  However, since there is no limit value for the engine speed when the engine speed is decelerated, there is a problem that if the engine speed is too low, the engine will stall when a sudden load is applied. For example, when the actual engine speed is lower than the set engine speed and a large load (such as when a piece of stone or a piece of wood bites) acts on a work machine such as a rotary, the engine stops. There is a problem.

  Also in the above-mentioned Patent Document 2, when the engine speed is instructed to be decelerated, there is no limit value for the engine speed, so if the engine speed is decreased too much as instructed, a sudden load is applied. Sometimes there are problems similar to those described above.

  An object of the present invention is to detect the load state of the engine during work, inform the operator of the current engine load state, and instruct the engine speed, travel speed and PTO speed to be changed, or automatically rotate the engine. It is to provide a work vehicle that can be operated in an appropriate state by performing change control of the number, the traveling speed, and the PTO rotational speed.

The above-described problems of the present invention are solved by the following solution means.
According to the first aspect of the present invention, the engine (5) mounted on the airframe, the work machine (18) connected to the airframe, the engine speed detection means (119), and the engine load acting on the engine (5) are calculated. Engine load calculating means (111), engine speed appropriateness determining means (113) for determining appropriateness of engine speed (N) based on the calculated engine load state, and engine speed (N) being not appropriate If it is determined, the engine speed change instructing means (114) for instructing to change the engine speed to an appropriate speed, and the instruction engine speed (Nk, Nk, instructed to change by the engine speed change instructing means (114)) Nj) is provided with shift instruction means (115, 116) for instructing a shift to the side for maintaining the traveling speed of the aircraft and the PTO rotation speed in a state before the engine rotation speed change instruction. Comparing means (117) for comparing the indicated engine speed (Nk) with a preset predetermined speed (Ns) is provided, and the indicated engine speed (Nk) is a predetermined speed (Ns). ) In the above case, a shift instruction is issued by the engine speed change instruction means (114) and the shift instruction means (115, 116), and when the indicated engine speed (Nk) is less than a predetermined speed (Ns), the engine A work vehicle characterized in that a control device (100) for instructing the predetermined rotation speed (Ns) is provided to the rotation speed change instructing means (114).

  According to the first aspect of the present invention, the actual engine speed is detected by the engine speed detecting means (119) and input to the control device (100). The engine load is calculated in the control device (100). Appropriateness of the engine speed is determined based on the calculated engine load state. If it is determined that the engine speed is not appropriate, the engine speed change instructing means (114) instructs to change to an appropriate engine speed. In order to change the engine speed to an appropriate value, it is necessary to maintain the airframe's traveling speed and PTO rotational speed so that they do not change. Therefore, the traveling speed and PTO rotational speed are determined by the shift instruction means (115, 116). Is instructed to shift to the side that maintains the state before the engine speed change instruction.

  A predetermined engine speed is set in the control device (100). This predetermined rotational speed is a rotational speed that causes an engine stall when a sudden load is applied. When the engine speed that is instructed to change by the engine speed change instructing means (114) is larger than a predetermined engine speed that causes the engine stall, the engine speed change instruction, the running speed, Instructs the PTO rotation speed to be changed. However, if the engine speed instructed to change by the engine speed change instructing means (114) is smaller than a predetermined engine speed that causes a preset engine stall, the engine speed is instructed to be the predetermined engine speed. To do.

  The invention according to claim 2 calculates the engine load acting on the engine (5) mounted on the airframe, the work machine (18) connected to the airframe, the engine speed detection means (119), and the engine (5). Engine load calculating means (111), engine speed appropriateness determining means (113) for determining appropriateness of engine speed (N) based on the calculated engine load state, and engine speed (N) being not appropriate An engine speed control means (126) for predicting an appropriate engine speed by the engine speed prediction means (118) and changing and controlling the predicted engine speed (Nk ′, Nj ′) when judged. Speed change means (1) for shifting to the side for maintaining the traveling speed of the airframe and the PTO rotation speed in the state before the change control to the predicted engine rotation speed (Nk ′, Nj ′) according to the predicted engine rotation speed. 7, 128) and a comparison means (117) for comparing the predicted engine speed (Nk ′) with a predetermined speed (Ns ′) set in advance. When the number (Nk ′) is equal to or greater than a predetermined number of revolutions (Ns ′), change control is performed by the engine revolution number control means (126), the traveling speed of the airframe and the speed change means (127, 128) of the PTO revolution number, Provided is a control device (100) for controlling the engine speed to be changed to a predetermined engine speed (Ns') by the engine speed control means (126) when the predicted engine speed (Nk ') is less than the predetermined speed (Ns'). This is a working vehicle.

  According to the second aspect of the present invention, the actual engine speed is detected by the engine speed detecting means (119) and is input to the control device (100). The engine load is calculated in the control device (100). Appropriateness of the engine speed is determined based on the calculated engine load state. If it is determined that the engine speed is not appropriate, the engine speed predicting means (118) predicts an appropriate engine speed. When changing to the predicted appropriate engine speed, it is necessary to maintain the traveling speed of the airframe and the PTO rotational speed so as not to change. Therefore, the traveling speed and the PTO rotational speed are changed by the speed change means (127, 128). The number is shifted to the side that maintains the state before the change to the predicted engine speed.

  When the engine speed predicted by the engine speed predicting means (118) is larger than the predetermined engine speed that causes the engine stall, the engine speed is changed to the predicted engine speed. The traveling speed and the PTO rotation speed are also changed.

  However, when the engine speed predicted by the engine speed predicting means (118) is lower than the predetermined engine speed that causes the engine stall, the engine engine speed becomes the predetermined engine speed. Change control to.

  According to the first aspect of the present invention, the engine load is calculated to instruct the engine speed to be changed to an appropriate engine speed, and the airframe traveling speed and the PTO speed are the values before the engine speed change instruction. By instructing to maintain the state, it becomes possible to operate under an appropriate load state and to reduce the fuel consumption. Further, when the engine speed that is instructed to be changed is less than a predetermined engine speed that causes a preset engine stall, the engine engine speed is set to the predetermined engine speed when the engine is suddenly loaded. Can be prevented.

  According to the second aspect of the invention, the engine load is calculated to predict an appropriate engine speed, the control is performed to change the engine speed so as to be the predicted engine speed, and the engine speed is predicted. The gear speed is controlled so that the traveling speed of the aircraft and the PTO rotational speed are maintained in the state before the engine rotational speed is changed to the predicted rotational speed in accordance with the change to the rotational speed. Operation is possible and fuel consumption can be reduced. Further, when the engine speed is less than the predetermined engine speed causing the engine stall, the engine engine speed is increased to the predetermined engine speed to prevent engine stall when a sudden load is applied.

  Embodiments of the present invention will be described with reference to the drawings. The present embodiment is a tractor capable of shifting to a main shift of 8 speeds and a sub-speed of 3 speeds, and a total of 24 speeds. FIG. 1 is a side view of the tractor 1, FIG. 2 is a power transmission mechanism diagram, and FIG. A schematic side view of the lever installation portion (FIG. 3A) and a plan view of the lever guide (FIG. 3B) are shown.

  The sub-transmission device is switched by the sub-transmission lever 34, and the acceleration / deceleration switch 37, 38 provided on the knob of the sub-transmission lever 34 is operated to switch the acceleration / deceleration of the main transmission one step at a time. It is a tractor that can change the main shift.

  The tractor 1 has front wheels 2 and 2 for steering and rear wheels 3 and 3 as propulsion wheels, and the rotational power of the engine 5 mounted in the bonnet 4 is appropriately decelerated by a transmission in the transmission case 6. The rotational power is transmitted to the rear wheels 3 and 3. The rotational power of the engine 5 may be transmitted not only to the rear wheels 3 and 3 but also to the front wheels 2 and 2 to drive all four wheels.

  Further, in the transmission case 6, a forward / reverse switching device 9 for switching the advancing direction of the airframe, a main transmission device 10 capable of shifting in eight steps, and an auxiliary transmission device 12 capable of shifting in three steps are connected in series. ing. These transmission systems will be described later with reference to FIG.

  In FIG. 1, a hydraulic cylinder case 14 is provided at an upper portion of the transmission case 6, and lift arms 15, 15 are pivotally attached to left and right sides of the hydraulic cylinder case 14. Lift rods 17, 17 are connected between the lift arms 15, 15 and the lower links 16, 16, and a rotary tiller 18, which is a work machine, is connected to the rear of the lower links 16, 16.

  When operating oil is supplied to the hydraulic cylinder 14a accommodated in the hydraulic cylinder case 14 by operating the hydraulic operation lever 28, the lift arms 15 and 15 are rotated upward, via the lift rod 17, the lower link 16, and the like. As a result, the work machine (rotary tiller 18) is raised. On the contrary, when the hydraulic control lever 28 is operated to the lower side, the hydraulic oil in the hydraulic cylinder 14a is discharged into the transmission case 6 which also serves as a hydraulic tank, and the lift arms 15 and 15 are lowered.

  A rotary tiller 18 is connected to the rear of the body of the tractor 1. The rotary tiller 18 includes a main cover 20 that covers the tiller 19, the upper part of the tiller 19, and a rear cover 22 that is pivotally attached to the rear of the main cover 20. Etc.

  A forward / reverse switching lever 27 for operating the forward / reverse switching device 9 is provided on the upper left side of the handle post 25 that supports the steering handle 24. When the forward / backward switching lever 27 is tilted forward from the neutral position, the aircraft moves forward. On the other hand, if you pull it backward, the aircraft will move backward.

Next, the power transmission system will be described based on the power diagram shown in FIG.
A main clutch 30 is provided at the rear of the engine 5, and a forward / reverse switching device 9 is provided at the rear of the transmission of the main clutch 30. The forward / reverse switching device 9 comprises multi-plate friction type hydraulic clutches 9a, 9b, which are normally maintained in a neutral position, and the forward hydraulic clutch 9a is connected by operating the forward / reverse switching lever 27 in the forward / backward direction. Alternatively, the reverse hydraulic clutch 9b is connected.

When the forward hydraulic clutch 9a is connected, power is transmitted from the input gear 60 via the gear 62 of the counter shaft 61 and the gear 65 of the reverser shaft 64 to the forward hydraulic clutch 9a, so that the reverser shaft 64 rotates forward. .
When the reverse hydraulic clutch 9b is connected, the reverse gear 73 is moved from the input gear 60 via the gear 62 of the counter shaft 61, the gear 66 of the counter shaft 61, and the gear 69 of the counter shaft 68. Then, power is transmitted to the reverse hydraulic clutch 9b, and the reverser shaft 64 rotates in the reverse direction.

  At the rear of the forward / reverse switching device 9, there is provided a first synchromesh main transmission 10 capable of four-speed shifting. When an actuator 31, 31 expands or contracts in response to a command from a controller 100 described later, a shifter 32, 32 is moved back and forth to change speed. In FIG. 2, when the front shifter 32 moves back and forth, the fourth speed and the third speed are obtained, and when the rear shifter 32 moves back and forth, the second speed and the first speed are obtained. In this case, when the main shift is switched, the hydraulic clutch of the hydraulic forward / reverse switching device 9 is first returned to neutral, and the hydraulic clutch of the forward / reverse switching device 9 is connected again after the shift. It is configured.

  A hydraulic second main transmission 11 that can be switched between high and low two stages is provided at the rear of the first main transmission 10. The front hydraulic clutch 11a is a high speed clutch, and the rear hydraulic clutch 11b is a low speed hydraulic clutch. Therefore, the main transmissions 10 and 11 in this embodiment are capable of 4 × 2 and 8 shifts.

  Further, the rear portion of the second main transmission 11 is provided with a sub-transmission 12 that is capable of three speeds and has a relatively large reduction ratio as compared with the main transmissions 10 and 11. As shown in FIGS. 2 and 3, when the sub shift lever 34 is operated to move the front shifter 35 back and forth, high speed (H) and medium speed (M) are obtained, and the rear shifter 35 is moved to the rear side. When moving to, low speed (L) is obtained.

  When the auxiliary transmission 12 is operated, the main clutch 30 needs to be turned on and off. That is, the main clutch pedal 29 is depressed to operate the sub-shift operation lever 34 in the front-rear direction or the left-right direction, and after the shift operation, the main clutch pedal 29 is released to transmit the engine rotational power to the transmission side.

  Note that the main transmissions 10 and 11 are shifted by pushing in a speed increasing switch 37 and a speed reducing switch 38 provided on the knob of the sub transmission lever 34 (see FIG. 2). Even if the acceleration switch 37 is pressed or the deceleration switch 38 is pressed, the shift is performed only one step at a time. The main transmissions 10 and 11 are shifted in the range from the first slow speed to the eighth fast speed. Then, the power decelerated by the auxiliary transmission device 12 is transmitted to the drive pinion shaft 40, and the rear wheels 3 and 3 are driven through the rear wheel differential device 41 and the final reduction device 42 in this order.

  The power branched from the rear wheel drive system in front of the rear wheel differential device 41 is used as a front wheel drive system. In the front wheel drive system, the front wheels 2 and 2 are driven at the same speed as the rear wheels 3 and 3, or the front wheels A front wheel speed increasing device 44 is provided for rotating 2 and 2 at a speed higher than that of the rear wheels 3 and 3. When the front hydraulic clutch 44a of the front wheel speed increasing device 44 is connected, the front wheel speed increasing state is established, and when the rear hydraulic clutch 44b is connected, the constant speed four-wheel driving state is established, and both hydraulic clutches 44a, 44b are engaged. When is turned OFF, only the rear wheels 3 and 3 are driven. A front wheel differential device 46 and a front wheel final reduction device 47 are provided on the front wheel drive shaft.

  In the power transmission diagram of FIG. 2, only when the auxiliary transmission 12 is at a high speed (H), if the auxiliary transmission lever 34 is moved sideways as it is (see FIG. 3B), It switches to the road speed position (HH) suitable for the road running speed. In this case, the main speed can be selected from the 1st to 8th speeds of the 5th, 6th, 7th, and 8th speeds on the high speed side. Even if 37 and 38 are operated, it cannot be selected in the program. When driving on the road, high speed driving is premised, so only the high speed side is prioritized, and the low speed side is automatically cut so that shifting operation is not performed so that it does not enter the 1st to 4th speeds, improving operability I am letting.

  In this embodiment, the selectable high-speed side shift pattern is four steps of 5, 6, 7, and 8. However, it is set to 3 steps of 6, 7, and 8 speeds, or 7 speeds. Alternatively, the number of shift stages may be reduced such that only the second stage of the eighth speed.

  FIG. 3 shows the positional relationship between the auxiliary transmission lever 34, the cockpit 48, and the lever guide 49. The lever guide 49 is provided on the left side of the cockpit 48. The shape of the lever guide 49 is an inverted U shape when viewed from above, and the sub-transmission lever 34 moves in the groove of the lever guide 49. As is clear from the figure, the high speed (H) and the medium speed (M) are in an opposing positional relationship, and the road speed (HH) and the low speed (L) face each other in the opposite groove.

  In the high speed (H) and the road speed (HH), only the shift range of the main transmissions 10 and 11 is changed without changing the shift position of the auxiliary transmission 12. That is, the position of the sub-transmission device 12 is at the high speed (H) position, and only the shiftable range of the main transmissions 10 and 11 in this state is changed by the program. The lever guide 49 is provided with four switches 50, 51, 52, 53 in order to detect which shift position the auxiliary transmission lever 34 for operating the auxiliary transmission device 12 is in. Instead of these switches 50, 51, 52, 53, a position of the auxiliary transmission operation lever 34 may be detected by a potentiometer type position sensor.

The PTO output shaft 83 is driven as follows.
Power is transmitted from the input gear 60 to the driving gear 75 of the PTO clutch 70 via the gear 62 of the counter shaft 61, and is transmitted to the PTO clutch 70. When the PTO clutch 70 is engaged, a four-speed transmission gear mechanism that is controlled to slide by two hydraulic cylinders 76 and 77 (a third gear 81a, a first gear 81b, a fourth gear 81c, and a second gear) The PTO drive shaft 71 is driven at the speed selected with the gear 81d.

  For example, when the gear 80 a on the driven shaft 79 slid by the hydraulic cylinder 76 meshes with the gear 81 a of the PTO transmission shaft 72, the output of the PTO output shaft 83 is output from the PTO transmission shaft 72 via the output gear 82 of the driven shaft 79. Power is transmitted to the gear 85 to drive the PTO drive shaft 71 (PTO 2nd speed). Similarly, when the gear 80b meshes with the gear 81b by the hydraulic cylinder 76, the PTO 4th speed is obtained.

When the gear 80c is engaged with the gear 81c by the hydraulic cylinder 77, the first PTO speed is achieved. When the gear 80d is engaged with the gear 81d by the hydraulic cylinder 77, the PTO third speed is obtained.
When the gear 80a is not engaged with the gear 81a and the reverse gear 87 on the reverse shaft 86 is slid to mesh with the gear 81a and also engaged with the gear 80a, the PTO drive shaft 71 is reversely driven. In the case of reverse rotation, this is only the first speed.

Conventionally, the operator can only recognize the load factor of the tractor only sensibly and empirically from the sound of the engine 5, the color of the exhaust smoke, and the vibration.
Therefore, in this embodiment, the sum of the traveling load corresponding to the engine speed and the engine exhaust temperature and the load of the PTO is calculated by the method described in Patent Document 1 to obtain the engine load acting on the engine 5. The load factor of the PTO drive shaft 71 (FIG. 2) is calculated from the ratio of the current PTO output to the PTO maximum output at each engine speed. Further, the traveling load is, for example, about 5% to 10% in the dry paddy, and the engine load acting on the engine 5 is mainly based on the load of the PTO drive shaft 71.

  Based on the engine load obtained from the sum of the travel load and the load of the PTO, it is determined whether or not the engine speed currently being output is appropriate, and if it is determined that the engine speed is not appropriate, the engine Change the rotation speed to an appropriate rotation speed.

Further, the traveling speed of the airframe and the PTO rotational speed are not changed in accordance with an appropriate change in the engine rotational speed. This is due to the following reason.
The tractor works by selecting the most suitable traveling speed and PTO rotational speed according to the field conditions. During the work, the work and the running are performed at the selected constant traveling speed and the selected constant PTO rotational speed. At this time, the traveling speed and the PTO rotational speed are changed according to the state of the field, but the work and the traveling are performed at a constant traveling speed and the PTO rotational speed even after the change.

  However, when the engine speed currently being output is changed to an appropriate speed based on the engine load as described above, the traveling speed and the PTO speed also change. Therefore, it is necessary to keep (maintain) the traveling speed and the PTO rotational speed before changing the engine rotational speed. Since the transmission of this embodiment is not a continuously variable transmission but a gear meshing stepped transmission, the transmission speed closest to the running speed and PTO speed before the engine speed change is set. desirable. In the present embodiment, as shown in FIG. 8, when the load is light A, the traveling stage and the PTO stage are increased by one stage, and when the load is heavy C, the traveling stage and the PTO stage are decreased by one stage. If a hydrostatic continuously variable transmission (HST), other belt-type continuously variable transmission, or a transmission equipped with a tridal continuously variable transmission is used, the traveling speed of the engine speed before the change is substantially matched. be able to.

FIG. 4 shows a block diagram provided with a control device (controller) 100 of the present embodiment, and FIG. 5 shows any engine load state among the loads A, B, and C currently shown in the drawing in the vehicle. FIG. 5 shows a flowchart for obtaining an instruction for changing the engine speed and for changing the running speed and the PTO speed. In the flowchart shown in FIG. 5, the calculation of “PTO speed from PTO speed and engine speed” is calculated as PTO reduction ratio = (PTO shaft speed) / (engine speed).
It can be done by seeking.

  The PTO shaft rotational speed is the rotational speed of the PTO drive shaft 71 shown in FIG. 2, and is detected by the PTO shaft rotational speed detection means 124a. As for the number of PTO stages, the PTO position detecting means 124 may directly detect the shift position of the PTO shift lever.

Further, step S14 of “Is PTO turned ON?” Is to detect whether or not the switch to be turned on when actually using the PTO-driven work machine is pressed. If not used, the tractor determines that the vehicle is traveling on the road (step S27) and does not give an instruction in this embodiment. However, a towing operation that does not perform PTO driving, such as a plow, can also be an instruction target. In this case, when “Is PTO turned ON?” Is NO, only the engine speed and the traveling speed stage are instructed.

  In the present embodiment, the engine load corresponding to the current engine speed detected by the engine speed detecting means (sensor) 119 and the engine exhaust gas temperature detected by the exhaust temperature detecting means (sensor) 120 is shown in FIG. The engine load calculation unit 111 calculates which zone of the loads A, B, and C belongs to the predetermined engine load map 112 shown in FIG.

  First, the exhaust temperature of the engine 5 is detected at step S10 in FIG. 5, and the engine speed and the PTO speed are detected at step S11. The PTO rotational speed is the rotational speed of the PTO drive shaft 71 and is detected by the sensor 124a. In step S12, the current PTO shift speed is calculated from the PTO rotational speed and the engine rotational speed. As another example, the position of the PTO shift lever may be directly detected.

In step S13, the load shown in FIG. 7 is calculated from the exhaust temperature and the engine speed.
In step S14, whether or not the PTO is in operation is confirmed by checking that the PTO switch for starting and stopping the PTO is turned on, and the process proceeds to a step for making the next engine load appropriate.

  Next, in step S15, it is determined whether or not the actual engine speed Nr exceeds a predetermined engine speed Ns (for example, preset 1600 rpm). If it is less than the predetermined engine speed, an instruction coefficient “0” is determined in step S16. To display on the display. In step S23, a message “Please increase the engine speed to a predetermined speed Ns (1600 rpm) or more” is displayed.

Further, if the actual engine speed Nr is equal to or greater than the predetermined engine speed Ns (1600 rpm), the current detection is performed depending on which of the engine loads A, B, and C in the map of FIG. Appropriateness of the actual engine speed Nr is determined by the engine speed appropriateness determining means 113.
The map of FIG. 7 is provided as an engine load map 112 in the control device 100 as shown in the block diagram of FIG.

  The engine loads A, B, and C are defined as “light load” when the load at a certain engine speed is light, “appropriate load” when the load is appropriate, and “heavy load” when the load is large. Correspond to each. In step 17 of FIG. 5, it is determined whether or not the load is light A, and whether or not the load is appropriate is determined in step 18. In step S19, the heavy load C is determined.

  When the engine speed is equal to or higher than the predetermined speed and the engine load is “light load A” or “heavy load C”, an instruction to change the engine speed is calculated by the engine speed change instruction unit 114 The engine speeds Nk and Nj are output to the display unit 125. Nk is the indicated engine speed at light load, and Nj is the indicated engine speed at heavy load.

  However, when the instruction engine speed (instruction engine speed at light load) Nk is less than the predetermined engine speed Ns, the engine engine speed is instructed to be the predetermined engine speed Ns. The display unit 125 is a display display, but may be output by voice or the like. In addition, the traveling speed and the PTO rotational speed of the airframe become the traveling speed and the PTO rotational speed before the engine rotational speed change described above in accordance with the instruction engine rotational speeds Nk and Nj instructed to change by the engine rotational speed change instructing means 114. Instruct to shift (to maintain).

  If it is determined in step S17 of FIG. 5 that the load is light A, in step S17, the engine speed appropriateness determination means 113 determines whether the engine speed is appropriate. If it is determined that the engine speed is not appropriate, in step 20, an instruction engine speed Nk to be changed by the engine speed change instruction means 114 is calculated.

  In step 21, the comparison engine 117 compares the designated engine speed Nk at the time of light load instructed to change with a predetermined speed Ns (1600 rpm). In particular, in the case of a light load A, since this is an operation for lowering the engine speed, it is important not to reduce the engine speed more than the predetermined speed Ns.

If the instructed instruction engine speed Nk is less than the predetermined engine speed Ns, the process proceeds to step S16, and the engine engine speed is instructed to be the predetermined engine speed Ns as described above.
As a result, the instructed engine speed Nk can be prevented from falling below the predetermined engine speed Ns, so that engine stall when a sudden load is applied can be prevented.

  When the instructed instruction engine speed Nk is equal to or greater than the predetermined engine speed Ns, the process proceeds to step S22, and the instruction coefficient “1” is selected and displayed on the display unit 125. Then, in step S23, “Please lower the engine speed to the command speed Nk and raise the traveling stage and the PTO stage by one stage” is displayed.

  Thereby, in the case of the light load A, the fuel efficiency is improved by lowering the engine speed. Further, by raising the traveling stage and the PTO stage by one stage, the traveling speed before the engine speed change and the PTO rotational speed are not significantly separated from each other, so that stable work can be performed.

  If it is determined in step S17 that the load is not light A, the process proceeds to step S18 to determine whether the load is appropriate load B or not. In the case of the appropriate load B, the process proceeds to step S24, the instruction coefficient “2” is displayed on the display unit 125, and the process further proceeds to step S23 to display the characters “appropriate engine speed”.

  If it is determined in step S18 that the load is not appropriate, the process proceeds to step S19 to determine heavy load C. In step S19, the engine speed determination unit 113 determines whether the engine speed is appropriate. In step S25, the engine speed Nj for heavy load to be changed by the engine speed change instructing unit 114 is calculated, and the process proceeds to step S26.

  In step S26, the instruction coefficient “3” is displayed on the display unit 125, and the process proceeds to step S23, where “display the engine speed is increased to the indicated engine speed Nj and lower the travel stage and the PTO stage by one stage”. Is displayed.

  This makes it possible to prevent engine drops under heavy load conditions and reduce black smoke emissions from the engine, and to prevent excessive separation from the running speed before changing the engine speed and the PTO speed. Is possible. In the case of the heavy load C, the engine speed is not lowered, so that the comparison with the predetermined speed Ns as in the case of the light load A is not performed.

The “instruction engine speed” is a number calculated by the following equation (1).
Instruction engine speed =
Current engine speed-(current speed x 0.25 x (2-instruction coefficient)) (1)
The reason why the coefficient “0.25” is selected in the above equation (1) is that there is an average change of 25% per vehicle speed shift of the tractor.
Here, as shown in FIG. 8, the instruction coefficient is set to an integer from 0 to 3 corresponding to each engine load.

  As described above, in accordance with an instruction to change to an appropriate engine speed according to the obtained load state of the engine 5, the instruction engine speed is compared with a predetermined engine speed set in advance. When the number is equal to or higher than the predetermined number of revolutions, a change instruction for making the engine speed appropriate is issued, and operation is possible at an appropriate engine speed. In particular, in the case of a light load A, the fuel consumption can be reduced. Further, when the instruction engine speed is less than the predetermined engine speed, the instruction engine speed is changed to the predetermined engine speed so that the engine is not stalled when a sudden load is applied.

  Here, the display on the display unit 125 and the voice instruction by the engine speed change instructing unit 114 may be too redundant and “inconvenient” depending on the operator. It is desirable to be able to arbitrarily change the instruction time at.

  Further, when an operation is being performed with the appropriate load B, an indicator lamp with a display such as “ECO” is displayed on the screen of the display unit 125, so that the operator can realize that energy saving work is in progress.

  Further, the engine load state is determined based on the engine speed and the exhaust temperature, and the relationship between the engine speed, the PTO output, and the temperature as shown in FIG. 9 is obtained as a regression curve for each engine speed, The current load of the engine 5 may be notified.

  In this case, the engine load state of the tractor can be recognized sensuously and empirically from the sound of the engine 5, the color of exhaust smoke, vibrations, etc., even if it is not a skilled operator. When there is a margin, the vehicle can run while limiting the engine speed, and when the load increases, energy saving operation can be achieved by maneuvering such as limiting the maximum vehicle speed by changing the reduction ratio.

  In this embodiment, the sub-shift position has a plurality of stages (three-stage shift). However, when the sub-shift position by the sub-shift position detecting means 122 is at the highest speed position, the vehicle is traveling on the road. The change instruction unit 114 does not perform display on the display unit 125 or instruction by voice.

  The flowchart of FIG. 5 described above is configured to instruct to change the engine speed according to the load state and only to instruct to change the traveling speed and the PTO speed, but the embodiment of the flowchart shown in FIG. The engine speed is changed automatically, and the traveling speed and the PTO speed are changed automatically.

Also in this embodiment, the actual engine speed Nr ′ detected by the engine speed detecting means (sensor) 119 and the engine exhaust gas detected by the exhaust temperature detecting means (sensor) 120 in the same procedure as in the first embodiment. The engine load calculation means 111 calculates whether the engine load corresponding to the gas temperature belongs to the engine load A, B, or C shown in FIG. 7 from a predetermined engine load map shown in FIG.

  First, the processing from step S10 to step S13 in FIG. 6 is the same as that in FIG. In step S30 following step S13, it is determined whether or not the PTO is turned on as in the case of FIG. In step S30, it is further determined whether or not automatic shift is on. The automatic transmission is turned on when the automatic mode switch 55 (FIG. 3) of the auxiliary transmission lever 34 is turned on.

  If both PTO and automatic transmission are on in step S30, the process proceeds to step S15. In step S15, it is determined whether the actual engine speed Nr ′ is equal to or greater than the predetermined engine speed Ns ′, the light load A is determined in step S17, the appropriate load B is determined in step S18, and the heavy load C is determined in step S19. The determination is the same as in the case of FIG.

  If the actual engine speed Nr 'is lower than the predetermined engine speed Ns' in step S15, the process proceeds to step S31, where the governor 126 automatically changes the engine engine speed to the predetermined engine speed Ns' (1600 rpm).

  If light load A is determined in step S17, the process proceeds to step S32. In step S32, the engine speed predicting means 118 calculates a predicted engine speed Nk 'at light load. In particular, in the case of a light load A, since this is an operation for lowering the engine speed, it is important not to reduce the engine speed more than the predetermined speed Ns ′.

  In step S33, if the predicted engine speed Nk 'at light load is equal to or lower than the predetermined speed Ns', the process proceeds to step S31, and the engine speed is controlled to be automatically set to the predetermined speed Ns'. If the predicted engine speed Nk ′ is equal to or greater than the predetermined speed Ns ′ in step S33, the process proceeds to step S34.

  In step S34, the engine speed is controlled to be the predicted engine speed Nk ', and it is further determined that the main shift (traveling speed) is increased by one and the PTO speed change position (PTO speed) is increased by one. In step S35, the governor 126 automatically controls the engine speed to become the predicted speed Nk '. Further, the main shift control unit 127 automatically raises the main shift (running speed) by one step and the PTO shift control unit 128 automatically raises the PTO shift position (PTO gear) by one step.

  As a result, the engine speed is controlled to automatically decrease when the load is light A, so that useless fuel consumption can be suppressed. Further, even if the engine speed is lowered, the traveling speed and the PTO rotational speed are set to a state close to the state before the engine speed change, so that stable work travel can be performed.

If it is determined that the load is appropriate B in step S18, the process proceeds to step S36, and the traveling speed and PTO shift are not performed.
If it is determined in step S18 that the load is not the proper load B, the process proceeds to step S19 to determine the heavy load C. If it is determined that the load is heavy C, the routine proceeds to step S37, where the engine speed prediction means 118 calculates a predicted engine speed Nj ′ at the time of heavy load. In the case of the heavy load C, since the engine speed is increased, the comparison with the predetermined speed Ns ′ is not performed.

Next, the routine proceeds to step S35, where the engine speed is controlled to become the predicted engine speed Nj ', and the main shift (traveling speed) is lowered by one step and the PTO speed changing position (PTO gear) is lowered by one step. I do.
In step S35, the governor 126 automatically controls the engine speed to become the predicted speed Nj ′. Further, the main shift control unit 127 automatically lowers the main shift (running speed) by one step and the PTO shift control unit 128 automatically reduces the PTO shift position (PTO gear) by one step.

  As a result, the engine stall can be prevented by automatically increasing the engine speed when the load C is heavy. Further, even if the engine speed is increased, the traveling speed and the PTO rotational speed are set to a state close to the state before the engine speed change, so that stable work traveling can be performed.

  The traveling vehicle of the present invention can be used as a work vehicle capable of energy saving work such as a tractor having a PTO or a construction vehicle.

It is a side view of the tractor of one Example of this invention. It is a power transmission mechanism figure from the engine of the tractor of FIG. FIG. 3 is a schematic side view (FIG. 3 (a)) of the auxiliary transmission lever installation portion of the tractor of FIG. 1 and a plan view (FIG. 3 (b)) of the lever guide. It is a block diagram which shows the structure of the control part of the tractor of FIG. 3 is a flowchart of control according to the first embodiment. 6 is a flowchart of control according to the second embodiment. It is an engine load map of the tractor of FIG. It is the engine load state and change state of the tractor of FIG. FIG. 2 is a relationship diagram of exhaust temperature and PTO output for each engine speed of the tractor of FIG. 1.

Explanation of symbols

1 Tractor 2 Front wheel 2
3 Rear wheel 4 Bonnet 5 Engine 6 Transmission case 9 Forward / reverse switching device 9a, 9b Hydraulic clutch 10 First main transmission 11 Second main transmission 11a, 11b Hydraulic clutch 12 Subtransmission 14 Hydraulic cylinder case 14a Hydraulic cylinder 15 Lift Arm 16 Lower link 17 Lift rod 18 Working machine (rotary tillage device)
DESCRIPTION OF SYMBOLS 19 Tilling part 20 Main cover 22 Rear cover 24 Steering handle 25 Handle post 27 Forward / reverse switching lever 28 Hydraulic operation lever 29 Main clutch pedal 30 Main clutch 31 Actuator 32 Shifter 34 Sub-shift lever 35 Shifter 37 Speed increase switch 38 Deceleration switch 40 Drive pinion 41 Rear wheel differential device 42 Final speed reducer 44 Front wheel speed increase device 44a, 44b Hydraulic clutch 46 Front wheel differential device 47 Front wheel final speed reducer 48 Pilot seat 49 Lever guide 50-53 switch 55 Automatic mode switch 58 Accelerator pedal 60 Input gear 61 Counter Shaft 62 Gear 64 Reverser shaft 65 Gear 66 Transmission gear 68 Counter shaft 69 Gear 70 PTO clutch 71 PTO drive shaft 72 PTO speed change shaft 73 Reverse gear 75 Gears 76, 77 Hydraulic cylinder 79 Drive shafts 80a to 80d Gear 81a to 81d Gear 82 Output gear 83 PTO output shaft 85 Output gear 86 Reverse rotation shaft 87 Gear 100 Control device (controller)
111 Engine load calculation means 112 Engine load map 113 Engine speed appropriateness determination means 114 Engine speed change instruction means 115 Traveling speed instruction means 116 PTO speed change instruction means 117 Comparison means 118 Engine speed prediction means 119 Engine speed detection means 120 Exhaust Temperature detection means 122 Sub-shift position detection means 124 PTO shift position detection means 124a PTO shaft rotation speed detection means 125 Display 126 Engine rotation speed control means 127 Travel speed transmission means 128 PTO speed change means N Engine speed Nr Actual engine speed Nr 'Actual engine speed Nk Indicated engine speed Nj at light load Instructed engine speed Nk at heavy load Predicted engine speed Nj at light load Predicted engine speed Ns at heavy load Ns Predetermined speed Ns' Predetermined Rotational speed

Claims (2)

An engine (5) mounted on the airframe and a work machine (18) connected to the airframe;
Engine speed detection means (119);
Engine load calculating means (111) for calculating an engine load acting on the engine (5);
Engine speed propriety determination means (113) for determining the propriety of the engine speed (N) based on the calculated engine load state;
When it is determined that the engine speed (N) is not appropriate, an engine speed change instruction means (114) for instructing to change the engine speed to an appropriate speed;
In accordance with the instruction engine speed (Nk, Nj) instructed to change by the engine speed change instructing means (114), the speed of the airframe and the PTO speed are changed to maintain the state before the engine speed change instruction. A work vehicle provided with shift instruction means (115, 116) for instructing;
Comparing means (117) is provided for comparing the indicated engine speed (Nk) with a predetermined speed (Ns) set in advance,
When the instructed engine speed (Nk) is equal to or greater than a predetermined speed (Ns), a shift instruction is issued by the engine speed change instructing means (114) and the shift instructing means (115, 116),
A control device (100) for instructing the predetermined engine speed (Ns) to the engine engine speed change instructing means (114) when the instructed engine engine speed (Nk) is less than the predetermined engine speed (Ns). Work vehicle. An engine (5) mounted on the airframe and a work machine (18) connected to the airframe;
Engine speed detection means (119);
Engine load calculating means (111) for calculating an engine load acting on the engine (5);
Engine speed propriety determination means (113) for determining the propriety of the engine speed (N) based on the calculated engine load state;
When it is determined that the engine speed (N) is not appropriate, the engine speed predicting means (118) predicts an appropriate engine speed and controls the change to the predicted engine speed (Nk ′, Nj ′). Engine speed control means (126);
Speed change means (127, 128) for changing the speed of the airframe and the PTO rotation speed in accordance with the predicted engine speed to the side that maintains the state before the change control to the predicted engine speed (Nk ′, Nj ′). A work vehicle provided with
Comparing means (117) for comparing the predicted engine speed (Nk ′) with a predetermined speed (Ns ′) set in advance is provided,
When the predicted engine speed (Nk ′) is equal to or higher than the predetermined speed (Ns ′), change control is performed by the engine speed control means (126), the traveling speed of the machine body, and the speed change means (127, 128) of the PTO speed. And
A control device (100) is provided for controlling the engine speed control means (126) to change to a predetermined engine speed (Ns') when the predicted engine speed (Nk ') is less than a predetermined speed (Ns'). A working vehicle characterized by that.

Images