JP2007269072A - Work vehicle - Google Patents

Abstract

In a work vehicle adopting a hybrid system, an electric motor can be efficiently driven even in a work vehicle that requires various travel modes.
The rotation of the engine E is transmitted to the front and rear wheels (4, 5) via the transmission (3), and the rotation of the engine (E) is charged using a generator (90). 91), the driving battery (92) of the electric motor (M1, M2) is charged, and the front wheel (4) and the rear wheel (5) are driven by the electric motor (M1, M2), respectively. In the work vehicle configured as described above, a means for detecting the peripheral speed of the front wheels (4) and the rear wheels (5) is provided, and the difference between the peripheral speeds is the two-wheel drive in which only the rear wheels (4) are driven to travel. When the value is equal to or greater than the predetermined value, the electric motor (M2) that drives the front wheel (5) is rotated and output.
[Selection] Figure 2

Description

  The present invention relates to a work vehicle such as an agricultural tractor, and more particularly to a hybrid work vehicle provided with an internal combustion engine and an electric motor as power sources.

  Conventionally, a working vehicle adopting a so-called hybrid system is equipped with an engine and a motor, and the driving force of the engine is used to drive the management machine body and the generator, and the driving force of the motor is used to drive the working machine. There is a technology that attempts to reduce the number of parts in a mission case by configuring it to be used (Patent Document 1).

In addition, there is a configuration in which the engine margin output is improved so as to be stored in a battery (Patent Document 2).
JP 2001-161104 A JP 2004-242558 A

  However, both Patent Document 1 and Patent Document 2 are configured so that the driving force of the electric motor is used to drive the work machine, but there is no consideration for the travel transmission system, and work requiring various travel modes. Improvement is still required in the case of vehicles.

In order to solve the above problems, the present invention has taken the following technical means.
That is, the invention described in claim 1 is configured to transmit the rotation of the engine E to the front and rear wheels (4, 5) via the transmission (3), and to transmit the rotation of the engine (E) to the generator (90 ) To charge the drive battery (92) of the electric motor (M1, M2) via the charger (91), and the electric motor (M1, M2) uses the front wheel (4) and the rear wheel ( 5) is provided with means for detecting the peripheral speed of the front wheels (4) and the rear wheels (5), and is driven by driving only the rear wheels (4). When the difference between the peripheral speeds is greater than or equal to a predetermined value, the work vehicle is configured to rotate and output to the electric motor (M2) that drives the front wheels (5). As a result, even if the two-wheel drive is selected when traveling on the road such as moving between fields, the front wheel (5) is also driven when the peripheral speed difference between the front and rear wheels exceeds a predetermined value due to the slip of the rear wheel (4). Escape from the slip state.

  According to a second aspect of the present invention, in the first aspect, the set vehicle speed (Vs) and the actual vehicle speed (Vn) are compared to determine whether or not the predetermined vehicle speed (Vn) is within the predetermined value (β). ), The rotation is output to the electric motor (M2) that drives the front wheels (5). This increases power transmission and improves acceleration performance.

  According to a third aspect of the present invention, there is provided a means for detecting a load current of the electric motor (M1, M2) according to the second aspect, wherein a difference between the set vehicle speed (Vs) and the actual vehicle speed (Vn) is the predetermined value ( If it is larger than β), the load currents of the electric motors (M1, M2) are read to determine whether or not each is overloaded. When the wheel is driven and the electric motor (M2) is overloaded, only the front wheel (5) is switched to the transmission gear and driven by the engine drive. As a result, when the electric motor (M1) is overloaded, both the front and rear wheels (4, 5) are switched to driving by the engine (E) via the transmission (3), and the electric motor (M2) is overloaded. When the vehicle is under load, the front wheels (5) are switched to drive by the engine (E) via the transmission (3).

  According to the first aspect of the present invention, even when the two-wheel drive is selected when traveling on the road such as the movement between fields, the front wheel (5) when the rear wheel (4) slips or the like causes the difference in the peripheral speed between the front and rear wheels to become a predetermined value or more. Can also escape from the slip state.

In addition to the effect of the first aspect, the invention according to the second aspect can increase power transmission and improve acceleration performance.
In the invention according to claim 3, in addition to the effect of claim 2, when the electric motor (M1) is overloaded, both the front and rear wheels (4, 5) are connected via the transmission (3) to the engine (E When the electric motor (M2) is overloaded, the front wheels (5) are switched to driving by the engine (E) via the transmission (3), so the electric motors (M1, M2) Can be protected, and driving can be stabilized.

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an agricultural tractor which is an example of a work vehicle. An engine E is mounted on the front portion of the tractor 1, and the rotational power of the engine E is transmitted to a transmission 3 in a transmission case 2. The rotational power decelerated by the transmission 3 is transmitted to the front wheels 4 and the rear wheels 5.

  A hydraulic cylinder case 6 is provided above the transmission case 2, and a lift arm 7 is pivotally attached to the hydraulic cylinder case 6. When the hydraulic oil is supplied into the hydraulic lifting cylinder in the hydraulic cylinder case 6, the lift arm 7 is turned up, and when it is discharged, the lift arm 7 is lowered.

  The lift arm 7 and the lower link 9 are connected by a lift rod 10, and a rotary tiller 12 as a work machine is connected to a three-point link mechanism composed of the lower link 9 and the top link 11, and the lift The arm 7 is configured to move up and down by driving up and down.

  The steering handle 13 disposed in the control unit at the center of the airframe is configured to steer the left and right front wheels 4 to the left and right by a left-right rotation operation, and a cockpit 14 is disposed behind the steering handle 13. A main transmission lever 15 and an auxiliary transmission lever 16 are provided near the cockpit 14.

  A throttle lever 17 is provided near the steering handle 13, an accelerator pedal 18 and left and right brake pedals 19, 19 are provided on the right side, and a clutch pedal 20 is provided on the left side near the feet below the handle 13. The accelerator pedal 18 is linked to the throttle of the engine E through a wire or the like, and is configured to control the rotational speed of the engine E in accordance with the amount by which the accelerator pedal 18 is depressed.

  FIG. 6 shows a power transmission path diagram of the traveling system of the tractor. Rotational power from the engine E is transmitted to the transmission 3 in the transmission case 2 via the transmission shaft 30. The transmission 3 includes a forward / reverse switching device 31 in the form of a multi-plate clutch, a main transmission 32 in the form of a multi-plate clutch, and an auxiliary transmission 33. The power from the transmission shaft 30 is input to the forward / reverse input shaft 34 of the forward / reverse switching device 31 and connected to the multi-plate clutch 35f side to be in the forward-side transmission state via the gear groups 36, 37, or the multi-plate The configuration is such that the reverse transmission state is established via the gear groups 38, 39, 40 by the connection of the clutch 35r. The multi-plate clutches 35f and 35r are both configured to be disconnected by detecting the disconnection of the clutch pedal sensor 41 that detects the depression of the clutch pedal 20, and are configured to replace the main clutch.

  In the illustrated example, the main transmission 32 includes four-stage transmission input gears 44, 45, 46, 47 disposed on the transmission input shaft 43, and transmission output gears 49, 50, 51, disposed on the transmission output shaft 48. The speed can be changed to four speeds by selecting and setting any one of the combinations with 52, and each speed switch 53, 54, 55, 56 disposed at each position of the main speed change lever 15 is turned on. In this configuration, the shift clutches 57, 58, 59, and 60 provided for each stage are selectively connected, and four-stage shift power is output to the shift output shaft 48.

  An extension portion of the speed change output shaft 48 is configured as a sub speed change input shaft 61, and two-stage gears 62, 63 provided fixedly to the sub speed change input shaft 61 are engaged with the sub speed change gears 65, 66 on the drive shaft 64. Thus, the mechanical sub-transmission device 33 is obtained in which the sliding clutch 67 member obtains a two-step shift by operating the sub-transmission lever 16.

The drive shaft 64 can transmit power to the left and right rear wheels 5 and 5 via a differential mechanism 68 and a final reduction mechanism 69, respectively.
An output gear 72 that interlocks with a transmission gear 71 provided on the start end side of the PTO transmission shaft 70 is disposed in the middle of the transmission shaft 30. A PTO shaft 73 protruding toward the rear of the machine body is interlocked with the end portion of the PTO transmission shaft 70.

  The drive shaft 64 includes an output gear 74 for front wheel transmission output, and the front wheel transmission shaft 77 is driven via an intermediate gear 75 and an input gear 76 that are interposed by using the PTO transmission shaft 70. . A front wheel speed increasing device 84 can be selected by selecting and connecting a pair of clutch means 78 and 79 provided on the front wheel transmission shaft 77 to standard rotation via the gears 80 and 81 and speed increasing rotation via the gears 82 and 83. The front wheel drive shaft 85 is configured to be able to transmit power to the left and right front wheels 4 and 4 via the front wheel differential mechanism 86 and the final reduction mechanism 87 in conjunction with the standard rotation or the speed increasing rotation. In addition, it can be set as the two-wheel drive state which makes the front-wheel drive shaft 85 a non-interlocking state by making the pair of clutch means 78 and 79 into a non-connection state.

  The power source of the agricultural tractor 1 of this embodiment is basically the engine E. However, the electric motor M1, M2, M3 is used in addition to the engine E as shown in FIG. It is configured to switch between a charging mode in which the electric motor M is charged and an assist mode in which the electric motor M assists the engine EW. When the load on the engine E is small, the battery 90 for driving the electric motor M is charged via the charger 91 using the generator 90.

  When the engine E is driven, the generator 90 is also operated, and the electric power generated by the generator 90 is stored in the battery 92 from the charger 91 (charge mode). The electric power stored in the battery 92 is supplied from the controller C to the electric motor M via the inverter 93.

  Of the electric motors M, the electric motor M1 has a configuration that allows the drive shaft 64 to be interlocked to transmit the rear wheels 4 independently. Specifically, the output gear 74 on the drive shaft 64 is configured to mesh with the output gear 94 of the electric motor M1, and the output gear 74 can rotate integrally with the shaft 64 by spline fitting. It is configured to be slidable in the axial direction, and can be selectively engaged with the output gear 94 of the electric motor M1 or the intermediate gear 75 for driving the front wheels.

  The electric motor M2 is configured to directly link the front wheel drive shaft 85, the electric motor M3 is configured to directly transmit the PTO transmission shaft 70, and is configured to independently transmit the front wheel 4 and the PTO shaft 73, respectively. .

  During the charging mode for the electric motor M, the power from the engine E is transmitted to the front and rear wheels 4 and 5 through the main and auxiliary transmissions 31 and 32, and the PTO shaft 73 is transmitted. The front and rear wheels 4 and 5 and the PTO shaft 73 are interlocked by the electric motor M by switching to the assist mode. The mode switching between the charging mode and the assist mode is performed by a mode switch 95 serving as a mode switching unit.

  The tractor 1 is configured to charge the battery 92 for driving the electric motor M with the generator 90 when the load of the engine E is small. The engine E load is detected by an engine load sensor 96, and the rotation speed of the engine E is detected by an engine rotation sensor 97. Further, the charging solenoid 98 is always on during the operation of the engine E, and the motor power transmission solenoid 99 is turned on when the assist mode of the electric motor M is entered. The engine transmission solenoid 100 is used for turning on and off the transmission of the engine E, and operates when the vehicle is set to travel only in the assist mode.

Next, the traveling state when the assist mode is selected will be described with reference to FIG.
When the assist mode is selected by the mode switch 95 and the load of the engine E is below a predetermined value, the mode is shifted to the assist mode, and the controller C rotates and outputs to the electric motor M (step 102). While reading the detection data of the various sensors, the vehicle speed setting dial 101 detection value is first read, and then the detection value of the accelerator pedal sensor 102 is read, so that the vehicle speed in straight traveling and thus the rotation speed of the electric motor M1 and the electric motor M2 are read. Can be determined (step 102 to step 106).

  Based on the detected value of the rear axle rotation sensor 103, the rotational speed of the electric motor M1 is first corrected to be increased / decreased based on a comparison between the set vehicle speed and the detected vehicle speed (step 109), and then the electric motor M2 is rotated at a rotation corresponding to the electric motor M1. A rotation interlocking output is performed (step 110).

  Furthermore, the work machine in which the type of the work machine is set with the work machine setting dial 104 is determined. For example, when a rotary work machine is mounted, rotation output is output to the electric motor M3 so that the rotation speed set by the PTO rotation speed setting dial 105 is set (step 111 to step 113), while when a plow work machine is mounted. Since the traction load is large, even if the assist mode is selected and set by the mode switch 95, the driving is forcibly switched from the driving by the electric motors M1 and M2 to the front and rear wheel transmission by the transmission of the engine E, and the assist mode is switched to the charging mode. Switching (steps 114 and 115).

  In step 105 in FIG. 4, it is determined whether or not the vehicle is in the turning mode. When it is determined that the vehicle is in the turning state, the vehicle is driven to travel in the procedure shown in FIG. That is, if there is an operation of the steering handle 13, if the steering sensor 104 detects a predetermined angle or more, it is determined as the turning mode, and it is determined whether the 2WD turning, the 4WD turning or the front wheel acceleration turning, and the rotation of the electric motors M1, M2 respectively. An output is made (step 201 to step 204). For example, in the front wheel acceleration turning, the ratio between the rotation speed of the rear wheel electric motor M1 and the rotation speed of the front wheel electric motor M2 is controlled so as to be the rotation ratio set by the front and rear wheel rotation ratio setting dial 105 (step). 205-step 207). If comprised in this way, since the ratio of the front-wheel and rear-wheel by front-wheel acceleration can be preset, it can turn at an appropriate ratio according to an operator's skill level, the wet field conditions of a field, etc.

  When 4WD turning is selected in step 205, the front / rear wheel rotation ratio is set to 1: 1. Alternatively, the front wheel may be set to be slightly faster. By selecting the 4WD turning in this way, the rotation ratio of the electric motors M1, M2 is controlled to a preset rotation ratio, so that the electric motors M1, M2 are released from the individual settings and the turning is easy.

Further, when 2WD turning is selected in step 205, the rotation output of the electric motor M2 is off and the driving to the front wheels is cut (step 210).
When the airframe is in a straight traveling state (step 204) and the accelerator pedal 18 is in a non-operating state and there is a brake operation, the battery is charged by the electric motors M1 and M2, and if it is detected that there is no braking operation, The battery is charged by the motor M1 (step 211 to step 214).

  The function of operating the clutch pedal 20 in the assist mode will be described with reference to FIG. The operation of the clutch pedal 20 is detected by the clutch pedal sensor 41, and the clutch engagement position or the disengagement position or the clutch depression amount can be detected. In the charging mode, after reading of the clutch pedal sensor 41, it is detected whether or not it has been turned off, and when it is in the turned position, the forward / reverse clutch 35 is turned off, otherwise the clutch 35 is kept in the connected state. (Step 302 to Step 305). On the other hand, in the assist mode, it is detected by the clutch pedal sensor 41, and when it is in the cut position, the electric motors M1 and M2 are turned off and are not interlocked with rotation (steps 306 to 308). The vehicle speed based on the value is called to control the rotational speeds of the electric motors M1 and M2 (steps 309 and 310). With this configuration, the vehicle speed is gradually increased as the clutch pedal 20 is gradually shifted from the depressed position to the engaged position in the same manner as in a normal clutch pedal operation feeling, and can be operated without a sense of incongruity. Note that after the speed is increased to a predetermined speed, the engine speed is constant, and thereafter, the engine speed is controlled so that the vehicle speed is calculated based on the detection result of the depression amount of the accelerator pedal 18 and the engine speed detection result.

Next, PTO rotation control will be described with reference to FIGS.
First, the PTO set rotational speed is read, and a predetermined rotational speed is output to the electric motor M3. Then, the output of the electric motor M3 is turned off when the detected value of the clutch pedal sensor 41 by the depression of the clutch pedal 20 is the cut position or the cut position + α (α> 0) (step 401 to step 406). On the other hand, as shown in FIG. 8 (b), when the electric motor M3 rotates at a predetermined number of revolutions, a work implement ascending command signal is output, the lift arm 7 is raised and rotated, and the lift arm angle sensor 106 determines the amount of rotation. If it is detected and it is detected that the position is the working machine raised position, the electric motor M3 is stopped and output (steps 407 to 409).

  FIG. 9 relates to electric motor control during traveling on the road such as movement between fields. First, it is determined whether or not the selection mode by the operation of the mode changeover switch is the assist mode, and various sensor detection values are read and rotated and output to the electric motor M1 (steps 501 to 503). Next, the front and rear axle rotational speeds are detected by the detection sensors 103 and 108 (step 504). When the rotational speed difference is greater than or equal to a predetermined value, the rotational speed is output to the control motor M2 to eliminate the rotational speed difference (step 505). 506). When the rotational speed difference is within the predetermined range in step 505, the set vehicle speed Vs is compared with the actual vehicle speed Vn calculated from the detected values of the detection sensors 107 and 108 for the front and rear axle rotational speeds. It is determined whether or not the value is β (step 507). Here, when the value is larger than the predetermined value β, a predetermined rotation output is output to the electric motor M2, and improvement is achieved. When the value is larger than the predetermined value β, the load currents of the electric motors M1 and M2 are read to determine whether each is overloaded (steps 508, 509, 510). If it is determined in step 509 that there is an overload, the front and rear wheels 4 and 5 are driven by engine driving by switching to gear shifting. When the electric motor M2 is overloaded, only the front wheels are switched to transmission gears and driven by engine drive (steps 511 and 512).

  In order to drive the rear wheel 5 with the electric motor M1 and to drive the front wheel 4 with the engine, the transmission configuration in FIG. 2 is improved as follows. That is, the drive shaft 64 has two front and rear shafts 64a and 64b, and a gear 74a is provided integrally with the front shaft 64a. The front wheel transmission shaft 77 is driven from the gear 74a through the intermediate gear 75 and the input gear 76. The configuration. A clutch pawl 74b is provided at the rear end of the gear 74a, and a clutch gear 74c that is spline-fitted to the rear shaft 64b and slidable in the axial direction is provided. When the clutch gear 74c is engaged with the clutch pawl 74b, the engine power is transmitted to the differential device 68 via the drive shafts 64a and 64b. On the other hand, when the gear portion of the clutch gear 74c is engaged with the output gear 92 of the electric motor M1, the rear wheels are driven by the electric motor M1, and the front wheels 4 can be independently driven by the engine (FIG. 10).

  FIG. 11 relates to start control during traveling on the road. When a lift arm load sensor 109 capable of detecting the load of the work machine 12 applied to the lift arm 7 is provided, and whether or not the work machine is mounted is determined based on the detection result, and when it is determined that the work machine is mounted Is driven by both the electric motor M1 and the electric motor M2 to be in a four-wheel drive state (steps 601 to 604). On the other hand, when it is determined that the work implement is not mounted, only the electric motor M1 is driven and Two-wheel drive is used. If comprised in this way, the start at the time of working machine mounting will become easy, and it will be hard to invite the overload state by two-wheel drive.

Tractor side view Transmission mechanism diagram Control block diagram Flow chart Flow chart Flow chart Clutch pedal sensor-speed relationship graph (A) (B) Flowchart diagram flowchart Transmission mechanism diagram showing another example Flow chart Front view showing an example of the operation panel

Explanation of symbols

E Engine M1 Electric motor M2 Electric motor C Controller 3 Transmission 4 Front wheel 5 Rear wheel 90 Generator 91 Battery charger 92 Battery 95 Mode changeover switch 103 Rear axle rotation sensor 108 Front axle rotation sensor

Claims (3)

The rotation of the engine E is transmitted to the front and rear wheels (4, 5) via the transmission (3), and the rotation of the engine (E) is transmitted via the charger (91) using the generator (90). Thus, the battery (92) for driving the electric motor (M1, M2) is charged, and the electric motor (M1, M2) is configured to drive the front wheel (4) and the rear wheel (5), respectively. The vehicle is provided with means for detecting the peripheral speeds of the front wheels (4) and the rear wheels (5), and the difference between the peripheral speeds is greater than or equal to a predetermined value when the vehicle is driven by driving only the rear wheels (4). A work vehicle configured to rotate and output to an electric motor (M2) that drives the front wheels (5). The set vehicle speed (Vs) is compared with the actual vehicle speed (Vn) to determine whether or not the vehicle speed is within a predetermined value (β), and when it is larger than the predetermined value (β), the electric motor that drives the front wheels (5) 2. The work vehicle according to claim 1, wherein the work vehicle is configured to rotate and output to a motor (M2). A means for detecting the load current of the electric motor (M1, M2) is configured, and when the difference between the set vehicle speed (Vs) and the actual vehicle speed (Vn) is larger than the predetermined value (β), the electric motor (M1, M2) ) To determine whether or not each is overloaded. When the electric motor (M1) is overloaded, the transmission is linked to the transmission to drive the front and rear wheels by driving the engine, and the electric motor (M2) is overloaded. 3. The work vehicle according to claim 2, wherein when it becomes, only the front wheels (5) are switched to transmission gears and driven by engine drive. 4.

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