JP2014143965A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tractor which uses an electric motor as a driving source and is configured compact by preventing enlargement of the electric motor.SOLUTION: In a tractor using an electric motor 6 as a driving source, the electric motor 6 is a PTO (power take-off) electric motor 6 for driving a working machine 14 having fixed torque characteristics, a PTO output part to a PTO output shaft 13 for driving the working machine 14 is installed on the output side of the electric motor 6, a revolution number representing the fixed torque characteristics of the electric motor 6 is set two times or more and three times or less the maximum value of the revolution number of the PTO output shaft 13, a PTO deceleration part 30 for obtaining the maximum value of the revolution number of the PTO output shaft 13 is installed between the PTO output part and the electric motor 6, and a traveling output part to traveling devices 18, 19 is installed on the output side of the PTO deceleration part 30. By installing the PTO deceleration part 30 between the PTO output part and the PTO electric motor 6, the PTO electric motor 6 can be miniaturized and a power source, such as a battery 5, can be miniaturized.

Description

  The present invention relates to a tractor that uses an electric motor as a drive source.

As a tractor using an engine and an electric motor as driving sources, there is Patent Document 1 below.
This tractor connects the transmission case and generator from the output shaft of the engine via the power split mechanism, supplies the power generated by the generator to the battery and the electric motor via the inverter, and uses the output shaft of the electric motor In a tractor that is connected to a mission case and drives the traveling device from the mission case, the traveling device can be driven by the driving force of the engine and the electric motor during work traveling. With this configuration, the remaining power of the engine driving force is effectively converted into the output of the electric motor, so that the fuel efficient tractor is obtained.

JP 2011-245906 A

  The tractor described in Patent Document 1 is a combination type of an engine and an electric motor, and a PTO (power take-off, a power source for a work machine) may be driven only by the motor depending on the situation. For this purpose, a large motor is provided, and there is a problem that the electric motor becomes large in order to ensure the torque of the electric motor.

  An object of the present invention is to provide a tractor having a compact configuration by preventing an increase in size of an electric motor in a tractor using an electric motor as a drive source.

The above-described problems of the present invention are solved by the following solution means.
The invention according to claim 1 is provided with a traveling device (18, 19) and a work machine (14), and an electric motor (6) is used as a drive source for the traveling device (18, 19) and the work machine (14). The electric motor (6) is a PTO electric motor (6) for driving the work machine (14) having a constant torque characteristic in which the torque is constant within a predetermined range of the motor rotational speed. A PTO output unit to a PTO output shaft (13) for driving the work machine (14) is provided on the output side of the PTO electric motor (6), and a predetermined torque characteristic indicating the constant torque characteristic of the PTO electric motor (6) is provided. The rotation speed is set to be not less than 2 times and not more than 3 times the maximum rotation speed of the PTO output shaft (13), and the PTO output shaft (13) is connected between the PTO output section and the PTO electric motor (6). PTO deceleration part (30) for obtaining the maximum value of rotation speed Only a tractor provided with a running system output portion of the travel device (18, 19) on the output side of the PTO speed reduction unit (30).

A second aspect of the present invention is the tractor according to the first aspect, wherein a traveling system electric motor (7) for outputting a driving force to the traveling system output section is provided separately from the PTO system electric motor (6).
The invention described in claim 3 is the tractor according to claim 2, wherein the traveling electric motor (7) is a motor having a smaller output than the PTO electric motor (6).

  According to a fourth aspect of the present invention, a travel speed reduction part (32) for obtaining torque of the travel device (18, 19) is provided between the PTO speed reduction part (30) and the travel system output part, and the travel speed reduction part The output to (32) is switched to the output of both the travel system electric motor (7) and the PTO system electric motor (6), the output of only the travel system electric motor (7), or the output of only the PTO system electric motor (6). The tractor according to claim 2 or 3, wherein the tractor can be configured.

  The invention according to claim 5 is provided with a selection switch (37) for selecting work travel and road travel, and during the work travel for selecting work travel by the selection switch (37), the PTO electric motor (6) and the While driving both the travel system electric motors (7), the road system electric motor (7) is driven by driving the PTO system electric motor (6) during the road travel where the selection switch (37) selects the travel on the road. The tractor according to any one of claims 2 to 4, wherein a control device (100) having a function of stopping is provided.

In a conventional tractor, even if an engine and an electric motor are used in combination, the PTO may be driven only by the motor. For this purpose, a large motor is provided.
On the other hand, in this configuration, a motor (constant torque characteristic) that forms a flat portion of torque at a motor rotation speed within a predetermined range is used as the PTO electric motor (6). The constant torque characteristic is a characteristic in which the torque is substantially constant with respect to the rotation speed.

  And about the rotation speed of this flat part, it sets to 2 times or more and 3 times or less of the maximum value of the output rotation speed to the PTO system output part actually used, and on the transmission downstream side of the PTO system electric motor (6), A PTO deceleration unit (30) for obtaining the maximum value of the necessary PTO output rotational speed is provided. Thus, the size of the PTO electric motor (6) itself is not increased without increasing the size of the deceleration portion (for deceleration from 1/2 to 1/3) and the size of the PTO electric motor (6) itself. It is possible to reduce the thickness. Therefore, even if the PTO deceleration unit (30) is provided, the size of the PTO deceleration unit (30) and the PTO electric motor (6) can be made smaller than that of the conventional motor.

  That is, according to the first aspect of the present invention, the PTO deceleration unit (30) for obtaining the torque of the PTO output shaft (13) is provided between the PTO system output unit and the PTO system electric motor (6). Thus, the PTO electric motor (6) can be reduced in size. If there is no PTO speed reduction part (30), the PTO system electric motor (6) must be enlarged to obtain the torque of the PTO system electric motor (6). The electric motor (6) can be downsized. In addition, miniaturization of the power source such as the battery (5) can be achieved by miniaturization of the PTO electric motor (6).

According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the traveling system electric motor (7) that outputs the driving force to the traveling system output unit separately from the PTO electric motor (6). ) Can be output to the traveling system output unit independently of the PTO system power transmission unit. Therefore, when shifting the travel device (18, 19), it can be performed independently and the operability is excellent.
A larger load than the traveling system acts on the PTO system. For this reason, when the PTO system and the traveling system motor are shared, the traveling speed may be slowed down or restored depending on the load. In this case, the aircraft hunts due to load fluctuations and the ride comfort is deteriorated. However, by using a separate motor for the traveling system, even when a large load acts on the work machine (14) side, particularly during work traveling. , Can run stably.

In general, the tractor has more work travel by the work implement than the road travel (non-work travel) for moving, and the travel system electric motor (7) having a small output is sufficient.
Therefore, according to the invention described in claim 3, in addition to the effect of the invention described in claim 2, the traveling electric motor (7) has a smaller output than the PTO electric motor (6). In addition, power consumption can be reduced and downsizing can be achieved.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 2 or claim 3, the traveling speed reducing portion (32) is provided between the PTO speed reducing portion (30) and the traveling system output portion. The motor to be used is selected according to the required torque by providing a configuration that allows switching to both the traveling electric motor (7) and the PTO electric motor (6). it can. For example, in the scraping work traveling, a large load may act on the traveling device (18, 19), so that it is stabilized by assisting with the PTO electric motor (6) in addition to the traveling electric motor (7). Driving is possible.

  According to the invention described in claim 5, in addition to the effect of the invention described in any one of claims 2 to 4, the PTO electric motor (6) and the traveling electric motor ( 7), while driving on the road, by driving the PTO electric motor (6) and stopping the traveling electric motor (7), the torque of the traveling devices (18, 19) is reduced during work traveling. If necessary, both the traveling electric motor (7) and the PTO electric motor (6) can be used. And the motor to be used can be selected according to a required torque.

  Normally, no load is applied when driving on the road, but the load is applied and torque is required for towing the heavy cargo truck or plowing (running in the field at the same high speed as when driving on the road). May be. In this case, a PTO electric motor (6) having a sufficient torque may be used.

It is a left view of the tractor of the Example of this invention. It is the motive power transmission system diagram of the tractor of FIG. 1, and the block diagram of a control apparatus. It is another example of the power transmission system diagram and block diagram of FIG. It is the figure which showed the torque characteristic of the electric motor. It is another example of the power transmission system diagram of FIG. It is a figure of the steering wheel vicinity.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall side view of a tractor referred to in the present invention. In this specification, the left and right directions in the forward direction of the tractor are referred to as left and right, respectively.

  A battery 5 and an electric motor 6 are mounted in a bonnet 15 at the front of the machine body, the power of the electric motor 6 is appropriately decelerated and decelerated in the mission case 3, and a front wheel shaft 16 protruding left and right before and after the mission case 3 The rear wheel shaft 17 is transmitted to drive both the front wheel 18 and the rear wheel 19 or only the rear wheel 19, and the PTO output shaft 13 protruding rearward of the transmission case 3 is driven. Although the front wheels 18 and the rear wheels 19 are shown as the traveling devices, a semi-crawler traveling device in which a crawler belt is wound around a triangle in a side view may be used instead of the rear wheels 19.

  A cabin 20 is placed on the body, and an operator travels in the cabin 20 while operating the steering handle 21 to steer the front wheels 18. A work machine 14 such as a rotary tiller is mounted on the lift arm 23 projecting backward from the machine body, and the work machine 14 is driven by a PTO output shaft 13 projecting rearward from the mission case 3. The tractor 1 performs work such as tillage in the farm field by driving the work machine 14 and running the machine body. The work machine 14 is lifted and lowered by a lift arm 23 (operated by a lift cylinder (not shown)).

  2 shows a power transmission system diagram of the tractor of FIG. 1 and a block diagram of the control device, FIG. 3 shows another example of the power transmission system diagram and block diagram of FIG. 2, and FIG. 6 shows the torque characteristics.

  The tractor 1 of the present embodiment uses the electric motor 6 as a drive source. The electric motor 6 is used as a PTO electric motor 6 for driving the work implement 14, and the PTO system is used as shown in FIGS. A PTO output unit for the PTO output shaft 13 is provided on the output side of the electric motor 6, and a PTO deceleration unit 30 for obtaining torque of the PTO output shaft 13 is provided between the PTO output unit and the PTO electric motor 6. Provided. A traveling system output unit for the front wheels 18 and the rear wheels 19 is provided on the output side of the PTO deceleration unit 30. And it is good to fix the reduction ratio of the PTO reduction part 30 to the gear ratio which can obtain the required maximum number of rotations as the number of rotations of the PTO output shaft 13. This maximum rotational speed is determined by the model (size of tractor and work content).

  As the PTO deceleration unit 30, a speed change mechanism such as a gear is used. In a mechanical speed change mechanism such as a gear, the speed can be changed only by the current value when the speed is changed by the PTO electric motor 6, and a trunnion shaft swash plate like a hydraulic continuously variable transmission (HST). Since the speed change is simple and the transmission efficiency is stable compared to HST (the transmission efficiency is about 97%).

  As shown in FIG. 4, the torque characteristic of the PTO electric motor 6 forms a flat portion with a rated torque ratio of 100% up to a rotational speed of 60 Hz (general specifications) (constant torque characteristic). By making the PTO electric motor 6 a motor having a rated level of 60 Hz, the cost can be reduced because it can be made inexpensive. In the constant torque characteristic of the motor, if the armature current is the same, the same torque is produced regardless of the rotational speed. This configuration uses this constant torque characteristic.

  Here, 60 Hz corresponds to 3600 rpm, and the PTO reduction unit 30 reduces the speed to about 1/3 (1200 rpm), for example. At this time, the torque is three times as it is the reciprocal of the reduction ratio. The PTO deceleration unit 30 may reduce the speed to about ½ (1800 rpm), and the torque of the PTO output shaft 13 is preferably 2 to 3 times. Considering the load acting on the PTO output shaft 13, the necessary torque can be obtained by decelerating the driving force of the PTO electric motor 6 so that the torque of the PTO output shaft 13 is 2 times or more and 3 times or less. be able to.

  Here, the rotational speed of the flat portion in FIG. 4 is set to be twice or more the maximum value of the rotational speed of the PTO output shaft 13 actually used. This maximum value is determined by the model (size of tractor and work contents). For example, when the maximum rotational speed of the PTO output shaft 13 is 1800 rpm, the rotational speed of the flat portion is at least 3600 rpm, and when the maximum rotational speed of the PTO output shaft 13 is 1200 rpm, the rotational speed of the flat portion is at least 2400 rpm. And

  And the deceleration part for obtaining the maximum value of the rotation speed of the PTO output shaft 13 required in the transmission downstream side of the PTO system electric motor 6 is provided. As a result, the size of the PTO deceleration unit 30 (for deceleration from 1/2 to 1/3) does not increase, and the PTO electric motor 6 does not increase.

  If there is no PTO deceleration unit 30, the PTO system electric motor 6 must be enlarged to obtain the torque of the PTO system electric motor 6. However, the PTO deceleration unit 30 allows the PTO system electric motor 6 to be downsized. It becomes. Further, the size reduction of the power source such as the battery 5 is achieved by the size reduction of the PTO electric motor 6.

  Then, using the PTO electric motor 6 in which the rotation speed of the flat portion is set to be not less than 2 times and not more than 3 times the maximum value of the rotation speed of the PTO output shaft 13, the output rotation speed of the PTO reduction unit 30 is thus obtained. However, if the reduction ratio is such that the maximum rotational speed of the required PTO output shaft 13 is about 1000 + α (α <1000), a large torque can be obtained with the small PTO electric motor 6. it can.

  Further, as shown in FIG. 2, a traveling electric motor 7 that outputs driving force to the traveling system output unit may be provided separately from the PTO electric motor 6. The traveling system electric motor 7 can output driving force to the traveling system output unit independently of the PTO system power transmission unit. Therefore, when shifting the front wheel 18 and the rear wheel 19, it can be performed independently and the operability is excellent. In particular, during work travel, even if a large load acts on the work implement 14 side, it can travel stably.

  If the traveling system electric motor 7 is a motor having an output smaller than that of the PTO system electric motor 6, the power consumption can be reduced and the size can be reduced. Normally, a tractor has a larger number of work travels by a work machine than a travel on the road for movement, so that the travel system electric motor 7 having a small output is sufficient.

  In addition, as shown in FIG. 2, a travel speed reduction unit 32 for obtaining the driving torque of the front wheels 18 and the rear wheels 19 is provided between the PTO speed reduction unit 30 and the travel system output unit, and output to the travel speed reduction unit 32. May be switched to an output from both the traveling electric motor 7 and the PTO electric motor 6, an output from the traveling electric motor 7 alone, or an output from the PTO electric motor 6 alone.

  By making the output of the traveling electric motor 7 and the PTO electric motor 6 switchable, the motor to be used can be selected according to the required torque. For example, when the driving torque of the front wheels 18 and the rear wheels 19 is necessary, such as during work travel, both the travel system electric motor 7 and the PTO system electric motor 6 can be used. In particular, by using the PTO electric motor 6 having a larger output than the traveling electric motor 7, it is possible to secure a torque necessary for work traveling. In the scraping work traveling, a large load may act on the front wheels 18 and the rear wheels 19, so that stable traveling is possible by assisting with the PTO electric motor 6.

  Specifically, PTO clutches 35 a and 35 b are provided on the output side of the PTO deceleration unit 30, and a travel system clutch 35 c is provided on the output side of the travel system electric motor 7. Each clutch 35a-35c can be turned on and off independently. The number of clutches 35a to 35c may be larger than this. The driving force is transmitted from the PTO deceleration unit 30 to the PTO system output unit (PTO output shaft 13 side) via the PTO system clutch 35a and to the travel reduction unit 32 via the PTO system clutch 35b. The driving force is transmitted to the traveling speed reduction unit 32 also from the traveling system electric motor 7 through the traveling system clutch 35c.

Therefore, the transmission and non-transmission of the driving force to the PTO output unit and the traveling output unit is performed by the on / off operation of the clutches 35a to 35c, thereby improving the operability of the tractor.
In addition, a selection switch 37 for selecting work travel and road travel is provided in the cabin 20 (in the vicinity of the steering handle 21 or the like), and the PTO electric motor 6 and the travel electric motor are used during work travel in which the work travel is selected by the selection switch 37. A control device (ECU) 100 having a function of driving the PTO system electric motor 6 and stopping the travel system electric motor 7 during driving on the road where both of the motors 7 are driven and the road switch is selected by the selection switch 37 is provided. And good. The traveling system electric motor 7 normally outputs to the traveling system output unit to the front wheels 18 and the rear wheels 19, but such usage is also possible.

In the illustrated example, two selection switches 37, ie, a PTO switch 37a and a traveling switch 37b are provided. However, a configuration may be adopted in which the motor used by one switch is switched.
When the PTO switch 37a is turned on by inputting the on / off signal of the PTO switch 37a and the travel switch 37b to the control device 100, both the motor drive devices 9 of the PTO system electric motor 6 and the travel system electric motor 7, When a signal is output to 10 and the travel switch 37b is turned on, a signal is output to the motor drive device 9 of only the PTO electric motor 6.

  By adopting this configuration, both the traveling electric motor 7 and the PTO electric motor 6 can be used when driving torque for the front wheels 18 and the rear wheels 19 is required during work traveling. And the motor to be used can be selected according to a required torque.

  Note that a load is not normally applied when traveling on the road, but a load may be applied and a torque may be required during towing traveling of a heavy cargo truck or plow work. In this case, a PTO electric motor 6 with sufficient torque may be used.

  When the PTO switch 37a is turned on and signals are output to the motor drive devices 9 and 10 of both the PTO electric motor 6 and the traveling electric motor 7, power consumption for traveling the tractor due to a downhill or the like When the amount is small, regenerative braking of electric power may be possible. Regenerative braking is a method of an electric brake that applies braking by operating a motor such as a motor, which is normally used as a driving force, as a generator and converting kinetic energy into electric energy and collecting it.

  By collecting the electric power from both the PTO electric motor 6 and the traveling electric motor 7 and charging the battery 5, the regenerative braking can be performed and the safety is increased although the generated energy cannot be exceeded. In addition, the power regeneration can be increased.

  Further, when the vehicle travels on the road where the vehicle switch is selected by the travel switch 37b, the PTO system clutch 35a on the PTO system output unit side is turned off (non-transmission), and the PTO system clutch 35b on the travel system output unit side is engaged (transmission). Further, the output to the PTO output shaft 13 may be cut off and the driving force may be transmitted to the traveling speed reduction unit 32.

  Then, by selectively using which one of the clutches 35a to 35c is engaged and which is to be disengaged, transmission and non-transmission of driving force to the PTO output unit and the traveling output unit can be performed.

  Each of the clutches 35a to 35c may be manually turned on and off. However, the clutch 35a to 35c is a hydraulic electromagnetic clutch, and a signal for turning on and off the PTO switch 37a and the travel switch 37b is input to the control device 100. If a signal of entering or cutting out to 35c is output, the labor of the operator can be saved.

Since it is not necessary to drive the work machine 14 when traveling on the road, by adopting this configuration, unnecessary output is not required and the loss of the battery 5 is reduced, leading to energy saving.
In addition, when traveling on the road where the traveling switch 37b selects the traveling on the road, the traveling speed reduction unit 32 in FIG. 2 may fix the speed reduction ratio and reduce the speed by changing the motor rotational speed of the PTO electric motor 6. Speed can be changed easily, transmission efficiency is stable, and driving torque is stable. The reason for limiting to traveling on the road is to change the speed while traveling on the road.

The traveling speed reducing unit 32 may be a hydraulic continuously variable transmission (HST), a belt type continuously variable transmission, a stepped transmission with a chain (structure like a bicycle), a geared stepped transmission, or the like.
Then, during work travel with the PTO switch 37a turned on, signals are output to the motor drive devices 9, 10 of both the PTO electric motor 6 and the travel electric motor 7, but this does not drive the PTO output shaft 13. The same applies to work using scraping or skiing.

That is, even during work travel, during work using scraping or skiing that does not drive the PTO output shaft 13, the PTO electric motor 6 outputs to the travel speed reduction unit 32.
Since the clutches 35a, 35b, and 35c are hydraulic electromagnetic clutches, if the work implement 14 is scraped or skived, the other shaft is not connected to the PTO output shaft 13, so this non-connection is provided on the PTO output shaft 13. Detected by the connection sensor 40.

  In this case, the PTO clutch 35a is disengaged, the PTO clutch 35b is engaged, and is not output from the PTO deceleration unit 30 to the PTO output shaft 13, but is decelerated from the PTO electric motor 6 via the PTO clutch 35b. Is output to the unit 32.

  In addition, the operation traveling without driving the PTO output shaft 13 includes the turning of the tractor during the plowing work with a cultivator or the like. It is desirable not to drive the PTO output shaft 13 during the turning of the tractor in order to prevent mud from scattering. And in such a case, the large torque required for work traveling can be secured by outputting from the PTO system electric motor 6 to the traveling system output unit.

  When the work implement 14 is raised during work travel, the PTO system clutch 35a and the travel system clutch 35c are operated so as to be transmitted to the travel speed reduction unit 32 via the PTO system clutch 35b. Also good. The steering handle 21 is provided with a steering angle sensor 60. When the steering angle sensor 60 detects a predetermined value or more (when the steering handle 21 is turned more than a predetermined amount), the control device 100 automatically operates the lift arm 23 to operate. Thus, the work machine 14 rises.

  Normally, the driving force is transmitted to the traveling speed reduction unit 32 by driving the traveling system electric motor 7 and entering the traveling system clutch 35c, but it happens to drive the PTO system electric motor 6 to engage the PTO system clutch 35b. In such a case, it is better to use this way.

  During swiveling of the tractor when plowing work is performed with a cultivator or the like, a large torque may be required particularly in wet fields. By adopting this configuration, a large torque necessary for work travel can be secured by outputting from the PTO electric motor 6.

FIG. 5 shows another example of the power transmission system diagram of FIG. This example differs from the power transmission system diagram of FIG. 2 in that the PTO deceleration unit 30 and the travel deceleration unit 32 are not provided.
Instead of providing a transmission that outputs driving force to the PTO system output unit and the travel system output unit, the speed may be reduced by changing the motor speed (output) of the travel system electric motor 7 or the PTO system electric motor 6. . That is, the traveling electric motor 7 and the PTO electric motor 6 also function as a speed reduction unit.

  The clutches 35a to 35c for transmitting and not transmitting the driving force from the motors 6 and 7 to the PTO system output unit and the traveling system output unit are necessary, and each output unit is turned on and off by the clutches 35a to 35c. The transmission and non-transmission of the driving force can be freely performed.

  When a transmission having a transmission mechanism such as a gear is provided in the PTO system output unit and the traveling system output unit, the noise of the gear becomes a problem. In particular, in a tractor that is not equipped with an engine and that uses an electric motor as a drive source, there is no engine noise, so gear noise is conspicuous.

  However, by adopting this configuration, the gear noise can be reduced, and the gear shift to the PTO system output unit and the travel system output unit can be made continuously variable, thereby improving the traveling performance and operability of the tractor. .

  FIG. 3 shows another example of the power transmission system diagram and block diagram of FIG. 2. In this example, the power transmission system diagram of FIG. 2 is not provided in that the traveling system electric motor 7 and the traveling system clutch 35c are not provided. And different.

  In this case, the traveling speed reduction unit 32 is not a fixed reduction ratio, and is equipped with a variable transmission (traveling variable speed reduction unit). The travel variable deceleration unit 32 includes HST and HMT (a combination of HST and a planetary transmission mechanism). Each has its own characteristics and transmission efficiency is different. Also in HST, the transmission efficiency is about 97% as described above, but there are speed ranges lower than 97% and higher speed ranges depending on the speed range. The trunnion shaft swash plate should be fixed (held in that position) in the speed range with the best transmission efficiency.

  By setting the traveling speed reducing unit 32 as a traveling variable speed reducing unit, it is possible to decelerate to an arbitrary speed. Then, the reduction ratio is maintained so that the transmission efficiency of the driving force in the traveling speed reduction unit 32 is near the maximum. By making the traveling speed reducing unit 32 a variable transmission, the speed can be changed easily, the transmission efficiency is stabilized, and the driving torque is stabilized.

  Also in the case of FIG. 3, the PTO clutches 35a and 35b can be turned on and off independently. The driving force transmitted to the traveling system output unit and the PTO system output unit can be freely controlled by turning the PTO system clutches 35a and 35b on and off using one PTO system electric motor as the motor.

  Also in the case of FIG. 3, when traveling on the road where the traveling switch 37 b selects the traveling on the road, the PTO system clutch 35 a on the PTO system output unit side is turned off (not transmitted), and the PTO system clutch 35 b on the travel system output unit side It is good also as a structure which cuts off the output to the PTO output shaft 13, and transmits a driving force to the driving | running | working deceleration part 32.

  When the vehicle travels on the road where the travel switch 37b selects road travel, the travel speed reduction unit 32 in FIG. 3 maintains the speed reduction ratio, and the motor speed of the PTO electric motor 6 is changed to reduce the speed. Speed can be changed easily, transmission efficiency is stable, and driving torque is stable.

  In the case of the configuration of FIG. 3, if the traveling variable speed reducing unit 32 is set to HST so that the speed of the tractor can be made zero without providing the PTO clutch 35b, the number of transmission parts such as the clutch is reduced, The configuration is simplified.

The trunnion shaft 47 for changing the inclination angle of a swash plate (not shown) for adjusting the hydraulic pressure output from the HST is neutralized by an HST lever (or an HST pedal) 45 by setting the travel variable deceleration unit 32 to HST. Since the tractor speed can be reduced to zero, the PTO clutch 35b is not required. The operation amount of the HST lever 45 is detected by a sensor, and the trunnion shaft 47 of the HST is rotated by a trunnion shaft drive motor (forward rotation side in forward rotation, reverse rotation side in reverse) 49 by the control device 100 corresponding to the detected value. .
With this configuration, finer speed control is possible.

Further, when the power consumption for traveling the tractor is small due to a downhill or the like, regenerative braking of power may be performed.
In this case, the speed reduction ratio of the travel variable speed reduction unit 32 may be maintained at a speed ratio at which the rotation speed of the PTO electric motor 6 is close to the maximum. When it is desired to rotate the front wheel 18 and the rear wheel 19 quickly, the power generated by increasing the power generation efficiency can be utilized to the maximum.

  Further, a monitor 50 such as a color liquid crystal panel is provided in the cabin 20 of the tractor. When the PTO switch 37a is turned off, the screen is displayed in green tone. When the PTO switch 37a is turned on, the screen is displayed in orange tone. The configuration is to be displayed. The control device 100 changes the base color of the screen of the monitor 50 based on the on / off signal of the PTO switch 37a.

  In a conventional engine-driven tractor, if the engine is turned off for some reason during the work, the engine cannot be restarted unless the PTO switch is turned off, and the tilling work may be started with the PTO switch turned off. .

According to this configuration, since it is easy to determine whether the PTO switch 37a is on or off based on the basic color of the monitor 50, the state of the PTO switch 37a can be confirmed, and plowing work can be performed with the PTO switch 37a turned off. There is no beginning. In particular, it is easy to recognize that it is safe by setting the green color as the cutting case, and it is easy to recognize that it is driven by setting it as the orange color when entering. The condition is suitable and suitable.
Since it is possible to visually confirm whether or not the working machine is in a driving state, the work can be performed more safely.

  The present invention is also applicable to work vehicles other than tractors.

DESCRIPTION OF SYMBOLS 1 Tractor 3 Mission case 5 Battery 6 Electric motor 7 Traveling electric motor 9, 10 Motor drive device 13 PTO output shaft 14 Working machine 15 Bonnet 16 Front wheel shaft 17 Rear wheel shaft 18 Front wheel 19 Rear wheel 20 Cabin 21 Steering handle 23 Lift arm 30 PTO decelerating section 32 Traveling decelerating sections 35a to 35c Clutch 37 selection switch 37a PTO switch 37b Traveling switch 40 Unconnected sensor 45 HST lever 47 Trunnion shaft 49 Trunnion shaft drive motor 50 Monitor 60 Steering angle sensor 100 Controller

Claims (5)

In a tractor including a traveling device (18, 19) and a work machine (14), and using the electric motor (6) as a drive source of the traveling device (18, 19) and the work machine (14),
The electric motor (6) is a PTO electric motor (6) for driving the work machine (14) having a constant torque characteristic in which the torque is constant within a predetermined range of the motor rotation speed. A PTO output unit to the PTO output shaft (13) for driving the work machine (14) is provided on the output side of the electric motor (6),
A predetermined rotational speed indicating a constant torque characteristic of the PTO electric motor (6) is set to be not less than 2 times and not more than 3 times the maximum value of the rotational speed of the PTO output shaft (13);
A PTO deceleration unit (30) for obtaining the maximum value of the rotational speed of the PTO output shaft (13) is provided between the PTO system output unit and the PTO system electric motor (6).
A tractor characterized in that a traveling system output unit to the traveling device (18, 19) is provided on the output side of the PTO deceleration unit (30).   The tractor according to claim 1, wherein a traveling system electric motor (7) that outputs a driving force to the traveling system output unit is provided separately from the PTO system electric motor (6).   The tractor according to claim 2, wherein the traveling electric motor (7) is a motor having a smaller output than the PTO electric motor (6).   A travel speed reduction part (32) for obtaining torque of the travel device (18, 19) is provided between the PTO speed reduction part (30) and the travel system output part, and the output to the travel speed reduction part (32) is traveled. The system can be switched to an output from both the electric motor (7) and the PTO electric motor (6), an output from the traveling electric motor (7), or an output from the PTO electric motor (6) only. The tractor according to claim 2 or 3.   A selection switch (37) for selecting work travel and road travel is provided, and during the work travel for selecting work travel by the selection switch (37), the PTO electric motor (6) and the travel electric motor (7) While driving both, a control device having a function of driving the PTO electric motor (6) and stopping the traveling electric motor (7) during road driving for selecting road driving by the selection switch (37) ( 100) is provided, The tractor of any one of Claim 2 to 4 characterized by the above-mentioned.

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