Electric work vehicle
11021071 · 2021-06-01
Assignee
Inventors
Cpc classification
B60K2001/0411
PERFORMING OPERATIONS; TRANSPORTING
B60L58/21
PERFORMING OPERATIONS; TRANSPORTING
B60L58/18
PERFORMING OPERATIONS; TRANSPORTING
B60L58/12
PERFORMING OPERATIONS; TRANSPORTING
B60L50/60
PERFORMING OPERATIONS; TRANSPORTING
Y02T10/70
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B60L2220/46
PERFORMING OPERATIONS; TRANSPORTING
B60K2001/0416
PERFORMING OPERATIONS; TRANSPORTING
B60K1/04
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60L50/60
PERFORMING OPERATIONS; TRANSPORTING
B60L58/12
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Disclosed is an electric work vehicle that includes a traveling vehicle body, a wheel unit having wheels on the right and left sides of the traveling vehicle body, a motor for supplying rotational drive force to the wheel unit, and a battery for supplying electric power to the motor. The battery includes a first battery disposed at a right/left center of the traveling vehicle body, and second batteries disposed in right/left symmetricity on the traveling vehicle body to act as supplementary batteries.
Claims
1. An electric work vehicle comprising: a traveling vehicle body; a wheel unit having wheels on the right and left sides of the traveling vehicle body; a motor for supplying rotational drive force to the wheel unit; a battery for supplying electric power to the motor, the battery including: a first battery disposed at a right/left center of the traveling vehicle body, a right/left centerline of the first battery being in substantial alignment with a right/left centerline of the traveling body; and second batteries disposed in symmetricity across the right/left centerline of the first battery and right and left fenders that are disposed on the right and left sides of the traveling vehicle body, wherein the second batteries are disposed on respective fenders, with at least a part of each of the second batteries being overlapped with the fender associated therewith in a top view of the traveling vehicle body.
2. The electric work vehicle as defined in claim 1, wherein: the first battery is disposed at a rear portion of the traveling vehicle body; and the second batteries are disposed in right/left symmetry across the first battery at the rear portion of the traveling vehicle body.
3. The electric work vehicle as defined in claim 1, wherein: the first battery is disposed at a front portion of the traveling vehicle body; and the second batteries are disposed at rear portions of the traveling vehicle body across the right/left centerline of the first battery.
4. The electric work vehicle as defined in claim 1, wherein: the second batteries include a second right battery disposed on the right side of the traveling vehicle body and a second left battery disposed on the left side of the traveling vehicle body; and the second left battery and the second right battery are identical in shape and weight to each other.
5. The electric work vehicle as defined in claim 1, further comprising: a switching mechanism for manually or automatically switching between the first battery and the second batteries.
6. The electric work vehicle as defined in claim 5, wherein: the switching mechanism controls an electric power amount supplied from the first battery to the motor and an electric power amount supplied from the second batteries to the motor to be substantially equal to each other.
7. The electric work vehicle as defined in claim 1, further comprising: a stored electric power control section configured to effect at least one of (i) a display control for displaying stored power amounts stored in the first battery and the second batteries and (ii) an alarm control for effecting alarming in accordance with the stored power mounts.
8. The electric work vehicle as defined in claim 1, wherein an even number of the second batteries are provided and only a single first battery is provided.
9. The electric work vehicle as defined in claim 8, wherein the second batteries are sized identically to each other in the top view of the traveling vehicle body.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
(6) Regarding an electric work vehicle according to the invention, preferred embodiments will be described next using as an example thereof, a riding electric lawn mower called a “zero-turn” mower having a mower unit mounted on a vehicle body. Unless indicated otherwise, a “front/rear direction” used in the detailed disclosure means a longitudinal direction of a vehicle body of the riding electric lawn mower which is the traveling direction of the riding electric work vehicle. A “lateral direction”, a “transverse direction” or a “right/left direction” means a direction horizontally traversing the vehicle body longitudinal direction. And a “vertical direction” or a “height direction” means the direction of the normal relative to the ground surface or the vehicle body horizontal plane.
(7) The riding electric work vehicle mounts thereon batteries for supplying electric power to a driving wheel unit having driving wheels, a mower unit having mower blades for mowing grass or lawn, etc. As a layout of the batteries, there are e.g. a type relating to a first embodiment in which the batteries are disposed at a rear portion of the riding electric lawn mower, and another type relating to a second embodiment in which the batteries are disposed in distribution at a front portion and a rear portion of the riding electric lawn mower. As typical examples, riding electric lawn mowers of each type will be described hereinafter.
First Embodiment
(8) [General Arrangement]
(9) As shown in
(10) Further, from the rear side of the driver's seat 11, a ROPS (rollover protection structure) frame 12 is mounted vertically. Rearwardly of the ROPS frame 12, a rear hood 45B is provided.
(11) Further, between the front wheel unit 1 and the driving wheel unit 2 and in a space beneath the frame unit 9, a mower unit 3 is suspended from the frame unit 9 to be liftable up/down via a lift link mechanism provided as a lift mechanism 13.
(12) Forwardly of the driver's seat 11, there is provided a floor plate 95 as a “footrest” for the foot of the driver, from which a brake pedal 14 protrudes. On the opposed sides of the driver's seat 11, there is provided a maneuvering unit 15 consisting of a left maneuvering lever 15a and a right maneuvering lever 15b which are pivotable about a horizontal pivot axis in the vehicle body transverse direction.
(13) Though not shown, around the driver's seat 11, there are disposed operational tools such as a mower blade operational lever, a mower unit lift pedal, etc.
(14) [Batteries]
(15) In the riding electric lawn mower, the driving wheel unit 2 and the mower unit 3 are driven by electric power. Thus, the riding electric lawn mower includes a battery 51 for supplying electric power to these units 2, 3. In the case of the electric lawn mower relating to the instant embodiment, the battery 51 includes a main battery (an example of a “first battery”) 51A and supplementary batteries (an example of a “second batteries”) 51B. The main battery 51A has an approximately rectangular parallelepiped body and is disposed rearwardly of the driver's seat 11. More specifically, this main battery 51A is disposed in such a manner that the right/left center of this main battery 51A is in substantial alignment with the right/left center of the traveling vehicle body 10. In the instant embodiment, the main battery 51A may be disposed beneath the rear hood 45B, for instance. However, the main battery 51A can be alternatively disposed within the rear hood 45B.
(16) Further, in the traveling vehicle body 10, as shown in
(17) Each of the right and left supplementary batteries 51B is approximately rectangular parallelepiped, and they are identical in shape and weight to each other. Thus, even when the supplementary batteries 51B are provided in addition to the main battery 51A, it is still possible to keep favorable weight balance in the right/left direction of the riding lawn mower.
(18) [Mower Unit]
(19) As shown in
(20) More particularly, the mower blade 20 located at the center in the vehicle body transverse direction (right/left direction) protrudes in the vehicle body forward traveling direction relative to the mower blade 20 disposed on the left side and the mower blade 20 disposed on the right side. In other words, the second rotational shaft 22 protrudes more to the front side in the vehicle body front/rear direction than the first rotational shaft 21 on the left side and the third rotational shaft 23 on the right side. With this arrangement, an unused space is created on the outer side of the rotational loci of the three mower blades 20, in particular, on the rear side of the vehicle body as seen in the plan view. As shown in
(21) In the example as shown in
(22) [Electric System and Power Transmitting System]
(23) As shown in
(24) In the battery 51, the main battery 51A and the supplementary batteries 15B are connected to the inverter 4 switchably by a switching mechanism 53. Thus, as being switched by the switching mechanism 53, the inverter 4 will be connected selectively to either the main battery 51A or the supplementary batteries 51B. The switching mechanism 53 can comprise a mechanism such as a switch and a relay, and can be switched manually or automatically.
(25) With provision of the switching mechanism 53 for switching over between the main battery 51A and the supplementary batteries 51B as described above, when the stored power amount in the main battery 51A becomes short, it is possible to switch over from the main battery 51A to the supplementary batteries 51B manually or automatically. Thus, in the event of shortage of power supply by the main battery 51A via the inverter 4 to the motors such as the left motor 61, the right motor 62 and the blade motor 64, etc., by switching from the main battery 51A to the supplementary batteries 51B, power can be supplied from the supplementary batteries 51B to the motors, so that a long working period for the riding electric lawn mower can be secured.
(26) Further, with the provision of the switching mechanism 53, power charging can be effected separately to the main battery 51A and to the supplementary batteries 51B, thus degree of freedom in charging can be increased.
(27) Moreover, since the switching mechanism 53 allows power supply to the motors from the main battery 51A and power supply to the motors from the supplementary batteries 51B to be effected independently, even if stored power amounts are different between the main battery 51A and the supplementary batteries 51B, power charging/discharging between the main battery 51A and the supplementary batteries 51B can be suppressed.
(28) Preferably, the switching mechanism 53 is configured to control the power amount from the main battery 51A to the motors and the power amount from the supplementary batteries 51B to the motors to be substantially equal to each other. Then, as the amounts of power supplied to the motors from the main battery 51A and the supplementary batteries 51B are made substantially equal to each other, even when switchover is effected between the main battery 51A and the supplementary batteries 51B, this will not result in any change in the amount of electric power supplied to the driving wheel unit 2 and the mower unit 3 before/after the switchover, so that these units 2, 3 can be driven smoothly.
(29) On the traveling vehicle body 10, there are disposed a left rotational speed detection sensor 71 functioning as a left rotational speed measurement section for detecting rotation (rotational speed) of the left motor 61 or the left rear wheel 2a, and a right rotational speed detection sensor 72 functioning as a right rotational speed measurement section for detecting rotation (rotational speed) of the right motor 62 or the right rear wheel 2b. Further, on the traveling vehicle body 10, there are also disposed a yawing rate detector 70 for detecting yawing of the traveling vehicle body 10, an acceleration sensor 73 for detecting an acceleration state of the traveling vehicle body 10, a left maneuvering angle detection sensor 74a and a right maneuvering angle detection sensor 74b.
(30) As shown in
(31) [Other Arrangements]
(32) The power supplies to the left motor 61 and the right motor 62 for traveling and to the blade motor 64 for mowing via the inverter 4 are effected automatically under an inverter control by a controller 5 which is also referred to as an ECU (electric control unit). However, these power supplies via the inverter 4 to the left motor 61 and the right motor 62 and to the blade motor 64 for mowing can be switched over with a manual operation by a user of an unillustrated operational unit.
(33) Further, though the left motor 61, the right motor 62 and the blade motor 64 are provided in the above-described arrangement, these motors can be configured as a single motor and power can be supplied from this single motor for providing rotational drives to the driving wheel unit 2 and the motor unit 3 in distribution.
(34) As the battery 51 for supplying electric power to the motors for rotatably driving the driving wheel unit 2 and the mower unit 3, there are provided the main battery 51A and the supplementary batteries 51B. Thus, in comparison with an arrangement having only the main battery 51A, it is possible to ensure a sufficient stored power amount in the battery 51 as a whole. Therefore, it is possible to secure a long operational period for the driving wheel unit 2 and consequently a long operational period for the riding electric lawn mower.
(35) Moreover, since the main battery 51A is disposed substantially at the right/left center at a rear portion of the traveling vehicle body 10 and the supplementary batteries 51B are disposed substantially in right/left symmetry at the rear portion of the traveling vehicle body 10, there is obtained favorable weight balance in the right/left direction of the riding electric lawn mower. Thus, with effective suppression of tilting of the gravity center of the riding electric lawn mower to either right or left side, the riding electric lawn mower can travel and make a stop, etc. smoothly.
(36) Moreover, as the supplementary batteries 51B are disposed on the right and left sides of the traveling vehicle body 10, these can be readily mounted/dismounted from the right and left sides respectively of the traveling vehicle body 10. Thus, when the supplementary batteries 51B are not needed, these supplementary batteries 51B can be readily dismounted. On the other hand, when the supplementary batteries 51B become necessary, the supplementary batteries 51B can be readily mounted. Thus, the work period associated with mounting and dismounting of the supplementary batteries 51B can be reduced advantageously.
(37) Incidentally, in the riding electric lawn mower relating to the first embodiment, the main battery 51A is disposed at a rear portion of the traveling vehicle body 10, and the supplementary batteries 51B are disposed substantially in right/left symmetry across the main battery 51A. Whereby, in the riding electric lawn mower having a free space at the rear portion of the traveling vehicle body 10, it is possible to employ a battery layout taking weight balance into consideration.
(38) Further, in the instant embodiment, since the supplementary batteries 51B are disposed respectively in correspondence with the fenders 41 that are provided on the right and left sides of the traveling vehicle body 10, these supplementary batteries 51B do not protrude from the right and left sides of the traveling vehicle body 10 prominently, so that the riding electric lawn mower can be formed compact.
Second Embodiment
(39) [General Arrangement]
(40) With reference to
(41) The riding electric lawn mower of the type relating to the second embodiment includes a frame unit 9 as a basic structure of a traveling vehicle body 10. The frame unit 9 includes a left frame and a right frame and a plurality of cross frames interconnecting the right and left frames, and a floor plate 95 around a driver's seat 11. The frame unit 9 is supported on a ground surface via a front wheel unit 1 consisting of freely rotatable caster type left front wheel 1a and right front wheel 1b, and a driving wheel unit 2 consisting of a left rear wheel 2a and a right rear wheel 2b. At a rear portion of the frame unit 9, the driver's seat 11 is disposed; and in the periphery of the driver's seat 11, there are provided a pair of right and left fenders 41.
(42) Further, from the rear side of the driver's seat 11, a ROPS (rollover protection structure) frame 12 is mounted vertically.
(43) Further, between the front wheel unit 1 and the driving wheel unit 2 and in a space beneath the frame unit 9, a mower unit 3 is suspended from the frame unit 9 to be liftable up/down via a lift link mechanism provided as a lift mechanism 13.
(44) Forwardly of the driver's seat 11, there is provided a floor plate 95 as a “footrest” for the foot of the driver, from which a brake pedal 14, a forward traveling speed changer pedal 82 and a reverse traveling speed changer pedal 83 coupled to a trunnion shaft of HST (hydrostatic transmission), etc. protrude. Forwardly of the driver's seat 11, there is disposed a steering wheel 81 for steering the front wheels. Forwardly of the steering wheel 81, a front hood 45F is provided.
(45) Though not shown, around the driver's seat 11, there are disposed operational tools such a mower blade operational lever, a mower unit lift pedal, etc.
(46) [Batteries]
(47) In the riding electric lawn mower, the driving wheel unit 2 and the mower unit 3 are driven by electric power. The riding electric lawn mower includes a battery 51 for supplying electric power to these units 2, 3. In the electric lawn mower relating to the instant embodiment, the battery 51 includes a main battery (an example of a “first battery”) 51A and supplementary batteries (an example of a “second batteries”) 51B. The main battery 51A has an approximately rectangular parallelepiped body and is disposed forwardly of the driver's seat 11. More specifically, this main battery 51A is disposed in such a manner that the right/left center of this main battery 51A is in substantial alignment with the right/left center of the traveling vehicle body 10. In the instant embodiment, the main battery 51A may be disposed inside the front hood 45F, for instance.
(48) Further, in the traveling vehicle body 10, as shown in
(49) Each of the right and left supplementary batteries 51B is approximately rectangular parallelepiped, and they are identical in shape and weight to each other. Thus, even when the supplementary batteries 51B are provided in addition to the main battery 51A, it is still possible to keep favorable weight balance in the right/left direction of the riding lawn mower.
(50) [Mower Unit]
(51) The configuration of the mower unit 3 is substantially same as that of the first embodiment. Although no mower blades are shown in the mower shown in
(52) [Electric System and Power System]
(53) In the battery 51, the main battery 51A and the supplementary batteries 15B are connected to be switched over manually or automatically, via a switching mechanism (which may be configured like the switching mechanism 53 in the first embodiment, though not shown in
(54) Preferably, the switching mechanism is configured to control the power amount from the main battery 51A to the motors and the power amount from the supplementary batteries 51B to the motors to be substantially equal to each other. Then, the driving wheel unit 2 and the mower unit 3 can be driven smoothly, as receiving no change in the power amounts before/after the switchover.
(55) To receive electric power from the battery 51 to drive the driving wheel unit 2 and the mower unit 3, there are provided motors. For instance, motors are provided independently of each other, in correspondence with the driving wheel unit 2 and the mower unit 3, respectively. Such motors may be provided in correspondence with the left rear wheel 2a and the right rear wheel 2b, respectively (the motors may be configured like the motors 61, 62, 64 in the first embodiment, though not shown in
(56) Since the supplementary motors 51B are provided in addition to the main battery 51A, it is possible to secure a longer operational period for the riding electric lawn mower than an arrangement including only the main battery 51A.
(57) Further, since the main battery 51A is disposed at a front portion of the traveling vehicle body 10 at the substantial right/left center of the traveling vehicle body 10 and the supplementary batteries 51B are disposed at rear portions of the traveling vehicle body 10 in substantial right/left symmetry, there is achieved favorable weight balance in the right/left direction of the riding electric lawn mower. Thus, with effective suppression of tilting of the gravity center of the riding electric lawn mower to either right or left side, the riding electric lawn mower can travel and make a stop, etc. smoothly. Still further, the main battery 51A disposed at the front portion of the traveling vehicle body 10 and the supplementary batteries 51B disposed at the rear portions of the traveling vehicle body 10 achieves favorable weight balance in the front/rear direction of the riding electric lawn mower.
(58) Moreover, as the supplementary batteries 51B are disposed on the right and left sides of the traveling vehicle body 10, these can be readily mounted/dismounted from the right and left sides of the traveling vehicle body 10.
(59) Incidentally, in the riding electric lawn mower relating to the second embodiment, since the main battery 51A is disposed at a front portion of the traveling vehicle body 10 and the supplementary batteries 51B are disposed in substantial right/left symmetry, in the riding electric lawn mower having a free space at the front portion of the traveling vehicle body 10, it is possible to employ a battery layout taking weight balance into consideration.
(60) Further, in the above-described embodiment, since the supplementary batteries 51B are disposed in correspondence with the respective fenders 41 that are provided on the right and left sides of the traveling vehicle body 10, these supplementary batteries 51B do not protrude from the right and left sides of the traveling vehicle body 10 prominently, so that the riding electric lawn mower can be formed compact.
Other Embodiments
(61) (1) In the first embodiment and the second embodiment described above, the riding electric lawn mower can include a stored power control section (not shown) which executes at least one of (i) display control for causing a display (not shown) to display stored power amounts stored in the main battery 51A and the supplementary batteries 51B and (ii) alarm control for effecting alarming in accordance with the stored power amounts.
(62) As stored power amounts of the main battery 51A and the supplementary batteries 51B are displayed and/or alarmed according to the stored power amounts, a user can switch over between the main battery 51A and the supplementary batteries 51B in accordance with the stored power amounts.
(63) The stored power control section can be preferably incorporated in the above-described controller 5 (ECU) or the switching mechanism 53, or can be provided in operable connection thereto in the vicinity of either one of them. However, the stored power control section may be provided in any other position or can be provided as an independent controller.
(64) (2) In the first embodiment and the second embodiment described above, there was cited a riding electric lawn mower called zero-turn mower in which the left front wheel 1a and the right front wheel 1b can be controlled in their driving independently of each other. However, the present invention is applicable to a lawn mower in which the left rear wheel 2a and the right rear wheel 2b are operably coupled via differential mechanism, with the left front wheel 1a and the right front wheel 1b acting as steerable wheels. In this case, the motors receiving power supply from the batteries will provide rotational drive to the left front wheel 1a and the right front wheel 1b.
(65) (3) In the foregoing embodiments, the mower unit 3 was equipped with three blades. Instead thereof, two or four or more blades can be provided.
(66) (4) In the foregoing embodiments, a lawn mower having a mower unit was cited as an example. However, the electric lawn mower can omit the mower unit. Further, the invention is applicable to an electric work vehicle operated by electric power, other than a lawn mower.
(67) (5) In the foregoing embodiments, in the periphery of the driver's seat 11, a pair of right and left fenders 41 are provided. However, the fenders 41 can be formed integral along the right/left direction around the driver's seat 11.