Electric work vehicle

Abstract

To provide a technology that enables proper arrangement of a component of an electric work vehicle.SOLUTION: An exemplary electric work vehicle comprises: a battery; an electric motor to which electric power is supplied from the battery; a traveling part that travels by a driving force of the electric motor; and a drive transmission part that transmits the driving force of the electric motor to the traveling part. The electric motor and the drive transmission part are arranged on one side of the battery.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electric work vehicle.

Background Art

[0002] Conventionally, an electric ride-on work vehicle including a pair of left and right drive wheels, a traveling motor that drives the drive wheels, and a battery for supplying power to the traveling motor is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When performing full electrification in which the work vehicle is driven only by electricity, the battery tends to be large because it is necessary to increase the capacity of the battery. On the other hand, when trying to perform as wide a range of work or long-term work as possible with a work vehicle that is fully electrified by a single charge of the battery, a small work vehicle with a small vehicle class and low power consumption is desired. For this reason, for example, problems arise such as how to appropriately arrange the battery and power electronics components required for the use of the battery in order to achieve compactness and optimization of the weight balance.

[0005] In view of the above points, an object of the present invention is to provide a technique capable of appropriately arranging components in an electric work vehicle.

Means for Solving the Problems

[0006] An exemplary electric work vehicle of the present invention includes a battery, an electric motor powered by the battery, a traveling unit that travels by the driving force of the electric motor, and a drive transmission unit that transmits the driving force of the electric motor to the traveling unit. The electric motor and the drive transmission unit are disposed on one side of the battery.

Advantages of the Invention

[0007] According to an exemplary aspect of the present invention, in an electric work vehicle, its components can be appropriately arranged.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

[0009] Embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

[0010] [[1. Outline of Electric Work Vehicle]] FIG. 1 is a diagram showing a schematic configuration of an electric work vehicle 1 according to an embodiment of the present invention. The electric work vehicle 1 can be used, for example, for various operations such as agricultural work, civil engineering work, or construction work. The electric work vehicle 1 preferably does not have a passenger space for an operator to ride. That is, the electric work vehicle 1 is an unmanned work vehicle on which an operator does not ride. The electric work vehicle 1 is operated by an operator located at a position away from the electric work vehicle 1 using a remote control device 2 provided to be capable of wireless communication with the electric work vehicle 1.

[0011] In addition, in the present embodiment, the electric work vehicle 1 can also perform work while automatically traveling in response to an instruction from an operator using the remote control device 2. However, the electric work vehicle 1 may be configured not to be able to automatically travel. Note that automatic driving means that at least steering is autonomously performed by controlling devices related to driving by a control device. In addition to steering, automatic driving may also autonomously perform, for example, adjustment of vehicle speed.

[0012] Generally, in an electric work vehicle, the proportion occupied by components such as batteries and power electronics components in the vehicle tends to increase. On the other hand, since it is necessary to perform work using only the power of the battery, when trying to perform work over as wide a range as possible or for a long time with a single charge of the battery, it is not easy to increase the vehicle class in view of power consumption problems, etc., and it is necessary to reduce the size of the vehicle. For this reason, when a passenger space is provided, there is a space conflict between the passenger space and the space for arranging components such as the battery. In this regard, in the electric work vehicle 1 of the present embodiment, since there is no passenger space, the degree of freedom in component layout can be increased. And because the degree of freedom in component layout can be increased, the basic performance of the work vehicle such as weight balance and compactness can be improved. Details of this point will be described later.

[0013] In addition, since the electric work vehicle 1 of the present embodiment can perform work without an operator boarding it, it can perform work safely even in a narrow space. Examples of work in a narrow space include management work in greenhouses and orchards. By using the electric work vehicle 1 without a passenger space, for example, it is possible to perform work without causing a situation where a part of the human body such as the neck gets caught on the beam of a house or the branches of fruit trees.

[0014] As shown in FIG. 1, the electric work vehicle 1 includes a vehicle body 10 and a working machine 3.

[0015] Here, for the convenience of the following description, the directions are defined as follows. The direction in which the vehicle body 10 and the working machine 3 are aligned is defined as the front-rear direction, and it is assumed that the working machine 3 is on the rear side when viewed from the vehicle body 10. The left side when looking from the rear to the front is defined as the left side, and the right side is defined as the right side to define the left-right direction. Further, the gravitational direction perpendicular to the front-rear direction and the left-right direction is defined as the up-down direction, the upstream side in the gravitational direction is defined as the upper side, and the downstream side is defined as the lower side. In the drawings, as necessary, the front is indicated by the symbol "F", the rear by "B", the right by "R", the left by "L", the upper by "U", and the lower by "D". Note that these directions are merely names used for explanation and are not intended to limit the actual positional relationship and direction.

[0016] Details of the vehicle body 10 will be described later.

[0017] The working machine 3 is connected to the vehicle body 10 using a working machine connection portion 11 provided at the rear end portion of the vehicle body 10. Specifically, the working machine 3 is detachably attached to the working machine connection portion 11. That is, the working machine 3 can be replaced with various types. In FIG. 1, the working machine 3 is a tiller. However, the working machine 3 may be, for example, a plow, a fertilizer applicator, a pesticide sprayer, a harvesting device, a mowing device, a snow removal device, an earth discharge device, etc. in addition to the tiller. In the present embodiment, the working machine 3 is provided so as to be liftable, but the working machine 3 may not be liftable.

[0018] In the present embodiment, the working machine 3 is attached only to the rear of the vehicle body 10, but this is merely an example. In addition to the rear of the vehicle body 10, a device for performing work may also be arranged in the front. Alternatively, the working machine may be attached only to the front of the vehicle body 10.

[0019] <2. Configuration of Vehicle Body> Next, the configuration of the vehicle body 10 will be described. First, with reference to FIGS. 2, 3, and 4, the schematic configuration of the vehicle body 10 will be described. FIG. 2 is a schematic perspective view showing the vehicle body 101 without the exterior cover 12 removed from the vehicle body 10 shown in FIG. 1 and the exterior cover 12. FIG. 3 is a schematic exploded perspective view showing the vehicle body 101 without the exterior cover shown in FIG. 2 disassembled. FIG. 4 is a schematic side view of the vehicle body 101 without the exterior cover shown in FIG. 2.

[0020] As shown in FIGS. 2 to 4, in addition to the exterior cover 12, the vehicle body 10 includes a traveling unit 13, a main frame 14, a traveling drive device 15, a power electronics (hereinafter sometimes referred to as power electronics) unit 16, a battery unit 17, and an electrical component arrangement frame unit 18. As shown in FIGS. 3 and 4, the traveling unit 13, the main frame 14, the power electronics unit 16, the battery unit 17, and the electrical component arrangement frame unit 18 are arranged one above the other in this order from bottom to top. The traveling drive device 15 is arranged in front of the main frame 14, the power electronics unit 16, and the battery unit 17.

[0021] Although not shown in FIG. 3, as shown in FIG. 4, behind the main frame 14, the power electronics unit 16, and the battery unit 17, the above-described working machine connection portion 11 for connecting the working machine 3 is arranged. The working machine connection portion 11 includes a working machine drive device 111 for operating the working machine 3. The working machine drive device 111 has an electric motor that serves as a drive source for operating the working machine 3 and a PTO (Power Take Off) power transmission portion that can transmit the power from the electric motor to the working machine 3.

[0022] [2-1. Traveling Unit] As described above, the electric work vehicle 1 includes a traveling unit 13. The traveling unit 13 enables the vehicle body 10 to travel. Specifically, the traveling unit 13 is composed of a pair of left and right crawlers 13a and 13b. The configurations of the left crawler 13a and the right crawler 13b are the same. For this reason, hereinafter, taking the case of the left crawler 13a shown in FIG. 4 as a representative example, the configurations of the crawlers 13a and 13b will be described.

[0023] The left crawler 13a includes a track frame 131 extending in the front-rear direction. In front of the track frame 131, a drive sprocket 132 attached to the external output shaft 62 (see FIG. 23 etc.) of the traveling drive device 15 is arranged as a drive wheel. At the rear end of the track frame 131, an idler 133 is arranged as a driven wheel. The idler 133 is rotatably supported by the track frame 131. Between the drive sprocket 132 and the idler 133 of the track frame 131, a plurality (five in this example) of rolling wheels 134 are rotatably supported. The left crawler 13a is configured by winding a crawler belt 135 around the drive sprocket 132, the idler 133, and the plurality of rolling wheels 134.

[0024] In this embodiment, the left and right crawlers 13a and 13b are configured such that one drive wheel (drive sprocket 132) and one driven wheel (idler 133) are arranged side by side in the front-rear direction and the crawler belt 135 is wound around them, but other configurations may also be possible. For example, each of the left and right crawlers may be of a type in which a crawler belt is wound around one drive wheel and two driven wheels in a triangular shape. However, a crawler with a flat configuration like that of this embodiment is preferable because it is easier to reduce the height of the vehicle and make the vehicle more compact. Also, in this embodiment, the traveling unit 13 is configured by the crawler method, but the traveling unit of the electric work vehicle may be configured by other methods than the crawler method, for example, it may be configured by the wheel method.

[0025] [2-2. Main Frame] The main frame 14, together with the traveling unit 13 and the traveling drive device 15, constitutes the chassis of the electric work vehicle 1. The main frame 14 is made of metal although there is no particular intention to limit the material. The above-described exterior cover 12 is attached at least to the main frame 14. The exterior cover 12 is fixed to the main frame 14 using fastening tools such as bolts and nuts. In the present embodiment, the exterior cover 12 is also attached to the electrical component arrangement frame portion 18.

[0026] As shown in FIG. 3, the main frame 14 includes a U-shaped upper frame portion 141 extending in the front-rear direction and a frame-shaped lower frame portion 142 disposed at a distance downward from the upper frame portion 141. The main frame 14 has a structure in which the upper frame portion 141 and the lower frame portion 142 are connected at a plurality of locations including the front end portion and the rear end portion. Due to such a configuration, the main frame 14 has an internal space surrounded by the frame. Further, the upper frame portion 141 is wider in the left-right direction (lateral width) than the lower frame portion 142. Very roughly speaking, the outer shape of the main frame 14 is trapezoidal with the upper side being longer than the lower side in a plan view (front view) from the front-rear direction.

[0027] As shown in FIG. 3, frame attachment portions 131a protruding inward in the left-right direction are provided at the front and rear portions of each track frame 131 of the left and right crawlers 13a and 13b. The main frame 14 is attached to the left and right crawlers 13a and 13b by overlapping the upper surfaces of these four frame attachment portions 131a and the lower surface of the lower frame portion 142 of the main frame 14 in a facing state and performing fastening using a fastening tool. That is, the electric work vehicle 1 includes a main frame 14 supported by the traveling unit 13. For example, bolts and nuts are used as the fastening tools for fastening the main frame 14 to the frame attachment portions 131a.

[0028] In addition, in the present embodiment, as a preferred form, the frame attachment portion 131a has a tread adjustment structure that enables changing the lateral interval (tread change) between the left and right crawlers 13a and 13b. The tread adjustment structure is, for example, a structure provided with a plurality of bolt holes in the lateral direction so that the lateral position of the bolts fastening the main frame 14 and the frame attachment portion 131a can be changed.

[0029] FIG. 5 is a schematic perspective view showing a state in which the main frame 14 is attached to the traveling unit 13. As shown in FIG. 5, in a state where the main frame 14 is attached to the traveling unit 13, the lower side of the lower frame portion 142 is disposed between the left and right crawlers 13a and 13b in the lateral direction. Also, the upper side of the lower frame portion 142 and the upper frame portion 141 are disposed above the upper ends of the left and right crawlers 13a and 13b. Specifically, the left frame portion of the U-shaped upper frame portion 141 is disposed laterally outward (leftward) of the inner end (right end) in the lateral direction of the left crawler 13a. Also, the right frame portion of the upper frame portion 141 is disposed laterally outward (rightward) of the inner end (left end) in the lateral direction of the right crawler 13b.

[0030] [2-3. Traveling drive device] As shown in FIG. 3, the traveling drive device 15 includes an electric motor 151 and a drive transmission portion 152. That is, the electric work vehicle 1 includes the electric motor 151 and the drive transmission portion 152. The drive transmission portion 152 transmits the driving force of the electric motor 151 to the traveling unit 13. Specifically, the drive transmission portion 152 transmits the driving force of the electric motor 151 to the above-described drive sprocket 132 (see FIG. 4). In other words, the traveling unit 13 travels by the driving force of the electric motor 151.

[0031] The traveling drive device 15 is attached to the traveling unit 13 and the main frame 14. As described above, the traveling drive device 15 has an electric motor 151. For this reason, in other words, the electric motor 151 is supported by the traveling unit 13 and the main frame 14. By supporting the electric motor 151 with a plurality of members in this way, the electric motor 151 can be firmly supported.

[0032] As shown in FIG. 5, at the front end of each track frame 131 of the left and right crawlers 13a and 13b, a first device mounting portion 131b having a rectangular plane (front end face) extending in the vertical direction (up and down direction) is provided. Further, on the front surface of the main frame 14, a pair of second device mounting portions 143a and 143b arranged at intervals in the left-right direction are provided. The pair of second device mounting portions 143a and 143b are arranged symmetrically left and right. The pair of second device mounting portions 143a and 143b are flat plate-like protruding pieces that protrude forward from the front surface of the main frame 14 and extend in the vertical direction.

[0033] FIG. 6 is a perspective view showing a schematic configuration of the traveling drive device 15. FIG. 6 is a view seen from a direction different from that of the traveling drive device 15 shown in FIG. 3 (specifically, diagonally rearward to the left). As shown in FIG. 6, at the lower part of the rear surface of the traveling drive device 15, a pair of lower mounting portions 153a and 153b arranged at intervals in the left-right direction are provided. The pair of lower mounting portions 153a and 153b have a rectangular plane (rear end face) extending in the vertical direction (up and down direction). Further, at the upper part of the rear surface of the traveling drive device 15, a pair of upper mounting portions 154a and 154b arranged at intervals in the left-right direction are provided. The pair of upper mounting portions 154a and 154b are provided symmetrically left and right. The pair of upper mounting portions 154a and 154b are flat plate-like protruding pieces that protrude rearward from the rear surface of the traveling drive device 15 and extend in the vertical direction.

[0034] When the traveling drive device 15 is attached to the traveling unit 13, among the pair of lower attachment portions 153a and 153b, the rear end surface of the left lower attachment portion 153a is overlapped in the front-rear direction in a state of facing the front end surface of the first device attachment portion 131b provided on the left crawler 13a. Also, the rear end surface of the right lower attachment portion 153b is overlapped in the front-rear direction in a state of facing the front end surface of the first device attachment portion 131b provided on the right crawler 13b. Then, the two overlapped portions are fastened by fasteners such as bolts and nuts, so that the traveling drive device 15 is fixed to the traveling unit 13.

[0035] In addition, similar to the case of attaching the main frame 14 to the traveling unit 13, the first device attachment portion 131b has a tread adjustment structure that enables tread change. The tread adjustment structure is, for example, a structure in which a plurality of bolt holes are provided in the left-right direction so that the left-right position of the bolts that fasten the lower attachment portions 153a and 153b and the first device attachment portion 131b can be changed.

[0036] Also, when the traveling drive device 15 is attached to the main frame 14, a pair of upper attachment portions 154a and 154b provided on the traveling drive device 15 side are arranged so as to sandwich a pair of second device attachment portions 143a and 143b provided on the main frame 14 side in the left-right direction. As a result, the left upper attachment portion 154a and the left second device attachment portion 143a overlap in the left-right direction, and the right upper attachment portion 154b and the right second device attachment portion 143b overlap in the left-right direction. Note that the left upper attachment portion 154a overlaps in a state of being positioned on the left side with respect to the left second device attachment portion 143a. The right upper attachment portion 154b overlaps in a state of being positioned on the right side with respect to the right second device attachment portion 143a. The left and right overlapping protruding pieces are fastened by fasteners such as bolts and nuts, so that the traveling drive device 15 is fixed to the main frame 14.

[0037] FIG. 7 is a perspective view showing a schematic configuration of a chassis 102 including a traveling unit 13, a main frame 14, and a traveling drive device 15. As shown in FIG. 7, the traveling drive device 15 is disposed in front of the main frame 14. Further, the traveling drive device 15 is disposed in front of a first idler 134a of the left and right crawlers 13a, 13b (see FIG. 4). The first idler 134a is an idler 134 disposed at the foremost end of the ground contact area of the crawlers 13a, 13b. The front end of the traveling drive device 15 is located in front of the front ends of the traveling unit 13 (the left and right crawlers 13a, 13b) (see FIG. 4).

[0038] With such a configuration, in the electric work vehicle 1, the traveling drive device 15 is configured to be disposed on the opposite side of the work implement connection portion 11 (specifically, the opposite side in the front-rear direction). In this case, the traveling drive device 15 can function as a counterweight for a vehicle rear member including the work implement 3. That is, by disposing the traveling drive device 15 at the front of the vehicle, the weight balance can be improved in a state where the work implement 3 is attached to the vehicle body 10. Further details of the traveling drive device 15 will be described later.

[0039] [2-4. Power Electronics (Power Ele) Section] The power ele section 16 is a portion where power ele components, which are electronic components including power control components such as an inverter and a converter, are intensively arranged, and has a structure in which at least some of the electronic components are unitized. As shown in FIG. 3, specifically, the power ele section 16 includes a storage box 161 and a high-voltage cable 163. The high-voltage cable 163 is an electric cable for high voltage such as 300V.

[0040] The storage box 161 is a box that houses at least some of the power electronics related components. Inside the storage box 161, for example, an inverter (described below), a DC-DC converter that converts high voltage to low voltage, a charger for charging the battery 171 included in the battery unit 17, a controller that integrally controls the power electronics components, an inverter for an external power supply for extraction (e.g., AC 100V), a junction box, a relay, a fuse box, and a blower (not shown in any case) for cooling the DC-DC converter, etc. are arranged. Inside the storage box 161, power electronics related components including power electronics components are arranged, and the storage box 161 can be said to be a power electronics unit. The storage box 161 is provided with a plurality of holes (not shown) through which electric wires for electrically connecting the components arranged inside and the external components pass.

[0041] The storage box 161 enables a plurality of electronic components including power electronics components to be unitized. By this unitization, when performing maintenance on the vehicle body 10, the plurality of electronic components can be detached and attached as a unit, so that the maintainability can be improved. Also, by unitizing, the number of attachment and detachment points of the harness during maintenance can be reduced, and the work load during maintenance can be reduced.

[0042] The inverter included in the power electronics unit 16 is connected to the battery 171 included in the battery unit 17, the electric motor 151 included in the traveling drive device 15, and an electric motor (not shown) included in the work implement drive device 111 by a high voltage cable 163. Also, the inverter is connected to a controller arranged inside the storage box 161 by a signal line. The inverter converts the DC power supplied from the battery 171 into AC power and supplies it to the electric motor.

[0043] In addition, in the present embodiment, the electric work vehicle 1 includes a cooling system 164 for cooling the inverter (see FIG. 3). The cooling system 164 is disposed behind the storage box 161. The cooling system 164 includes a pipe 164a through which a coolant for cooling the inverter flows, a pump 164b for circulating the coolant, and a tank 164c for storing the coolant. In addition, the cooling system 164 may include a radiator. The cooling system 164 may or may not be included in the power electric unit 16.

[0044] FIGS. 8 and 9 are diagrams for explaining the attachment structure of the storage box 161 to the chassis 102. FIG. 8 shows a state before the storage box 161 is attached to the chassis 102. FIG. 9 shows a state where the storage box 161 is attached to the chassis 102.

[0045] As shown in FIGS. 8 and 9, the storage box 161 has an L-shaped structure in plan view in which the front part is wider in the left-right direction than the rear part. In addition, an extension member 1611 extending in the left-right direction is attached to the upper edge of the rear end of the storage box 161. The extension member 1611 extends leftward beyond the left side surface of the rear part of the storage box 161.

[0046] On the left side surface of the storage box 161, a first leg portion 161a protruding leftward from the upper edge of the front part of the box and a second leg portion 161b protruding leftward from the left end of the extension member 1611 are provided. The first leg portion 161a and the second leg portion 161b are arranged at intervals in the front-rear direction with the same positions in the vertical and horizontal directions. On the right side surface of the storage box 161, a third leg portion 161c protruding rightward from the upper edge of the front part of the box and a fourth leg portion 161d protruding rightward from the upper edge of the rear part of the box are provided. The third leg portion 161c and the fourth leg portion 161d are arranged at intervals in the front-rear direction with the same positions in the vertical and horizontal directions.

[0047] On the left frame 141a of the upper frame part 141 that constitutes the main frame 14, the first mounting part 1411, the second mounting part 1412, and the third mounting part 1413 are arranged in this order from the front to the back at intervals in the front-rear direction. Also, on the right frame 141b of the upper frame part 141, the fourth mounting part 1414, the fifth mounting part 1415, and the sixth mounting part 1416 are arranged in this order from the front to the back at intervals in the front-rear direction. Some of these mounting parts 1411 to 1416 are used in combination with the four legs 161a to 161d of the storage box 161.

[0048] When the storage box 161 is attached to the chassis 102, the first leg 161a and the first mounting part 1411 are arranged overlapping each other in the vertical direction. Also, the second leg 161b and the third mounting part 1413 are arranged overlapping each other in the vertical direction. Also, the third leg 161c and the fifth mounting part 1415 are arranged overlapping each other in the vertical direction. Also, the fourth leg 161d and the sixth mounting part 1416 are arranged overlapping each other in the vertical direction. And the overlapping parts are fastened using fasteners such as bolts and nuts. Note that the storage box 161 is attached to the main frame 14 after taking anti-vibration measures, which will be described later.

[0049] Since the first to fourth legs 161a to 161b of the storage box 161 are arranged at the upper end of the storage box 161, the storage box 161 is attached to the chassis 102 in a state where the periphery (side surface part) is surrounded by the main frame 14. In other words, the storage box 161 attached to the chassis 102 is arranged inside the main frame 14.

[0050] Note that in the above, the number of locations where the storage box 161 is attached to the main frame 14 is four, but this is only an example, and the number and position of the locations where the storage box 161 is attached to the main frame 14 may be changed as appropriate.

[0051] In addition, in this embodiment, the storage box 161 is provided in an L shape in plan view, but the shape of the storage box 161 may be changed as appropriate.

[0052] As shown in FIGS. 9 and 4, etc., the power generation unit 16 is arranged behind the traveling drive device 15. Further, the power generation unit 16 is arranged in front of the work implement connecting portion 11 including the work implement drive device 111. Furthermore, the power generation unit 16 is arranged so as to overlap the traveling unit 13 in plan view. Specifically, in plan view, a part of the power generation unit 16 is arranged between the left and right crawlers 13a, 13b, and another part is arranged so as to overlap at least one of the left and right crawlers 13a, 13b.

[0053] Also, the power generation unit 16 is arranged between the battery 171 and the traveling unit 13 in the vertical direction. In other words, at least one power generation component is arranged between the battery 171 and the traveling unit 13. In the traveling unit 13 composed of the left and right crawlers 13a, 13b, a gap is generated between the left and right crawlers 13a, 13b. A part of the power generation unit 16 (power generation component) may enter this gap. Even in such a case, as long as a part of the power generation component exists between the lower end of the battery 171 and the upper end of the traveling unit 13 in the vertical direction, the power generation component is regarded as existing between the battery 171 and the traveling unit 13. By arranging the battery 171, the power generation unit 16 (power generation component), and the traveling unit 13 side by side, the outer shape of the electric work vehicle 1 can be made compact by using the space without waste.

[0054] In this embodiment, electronic components (power electronics related components) including power electronics components are arranged at the central part in the vertical direction of the electric work vehicle 1. That is, the power electronics related components are integrally arranged near the center of gravity of the electric work vehicle 1. When the electric work vehicle 1 is disturbed by a step on the road surface or the like, it tends to rotate around the center of gravity. In this regard, according to this embodiment, since the power electronics related components are integrally arranged near the center of the rotation, the sway of the power electronics related components due to the disturbance can be reduced. In particular, power electronics components are often delicate to vibration, and it is important to suppress the vibration of the power electronics components by arranging them as in this embodiment. That is, by arranging the power electronics unit 16 as in this embodiment, the reliability of the electric work vehicle 1 can be improved.

[0055] [2-5. Battery unit] As shown in FIG. 3, the battery unit 17 includes a battery 171 and a battery frame 172. That is, the electric work vehicle 1 includes the battery 171. As described above, the battery 171 supplies power to the electric motor 151 that is the drive source of the traveling unit 13. In other words, the electric motor 151 is supplied with power from the battery 171. Also, as described above, the battery 171 supplies power to the electric motors included in the work implement drive device 111 that is the drive source of the work implement 3.

[0056] The battery frame 172 supports the battery 171. Specifically, the battery frame 172 has a left battery frame portion 172a, a right battery frame portion 172b, and a front battery frame portion 172c. The left battery frame portion 172a and the right battery frame portion 172b each have a ladder shape with two upper and lower frames and a plurality of connecting frames connecting the two frames. The left battery frame portion 172a and the right battery frame portion 172b are arranged at intervals in the left - right direction. The distance between the left battery frame portion 172a and the right battery frame portion 172b in the left - right direction is the same as the distance between the left frame 141a and the right frame 141b (see FIG. 8) of the upper frame portion 141 of the main frame 14. The front battery frame portion 172c connects the front end portion of the upper frame of the left battery frame portion 172a and the front end portion of the upper frame of the right battery frame portion 172b.

[0057] The battery 171 is arranged so as to be surrounded by the right battery frame portion 172b, the left battery frame portion 172a, and the front battery frame portion 172c. The battery 171 is attached to the battery frame 172 via at least one battery attachment piece 173 (see FIG. 10). Note that the battery 171 may be attached to the battery frame 172 without passing through the battery attachment piece 173.

[0058] The battery 171 is attached to the main frame 14 via the battery frame 172. With the configuration of attaching the battery 171 to the main frame 14 using the battery frame 172, even when the shape of the battery 171 is changed, the battery 171 can be attached to the main frame 14 without changing the shape of the main frame 14.

[0059] FIG. 10 and FIG. 11 are diagrams for explaining the mounting structure of the battery unit 17 to the chassis 102. FIG. 10 shows the state before the battery unit 17 is mounted to the chassis 102. FIG. 11 shows the state after the battery unit 17 is mounted to the chassis 102. In FIGS. 10 and 11, the power electronics unit 16 is already mounted on the chassis 102.

[0060] On the left side surface of the battery frame 172, the first mounting location 1721, the second mounting location 1722, and the third mounting location 1723 are provided at intervals in this order from the front to the rear on the lower frame of the left battery frame portion 172a. Also, on the right side surface of the battery frame 172, the fourth mounting location 1724, the fifth mounting location 1725, and the sixth mounting location 1726 are provided at intervals in this order from the front to the rear on the lower frame of the right battery frame portion 172b.

[0061] When mounting the battery unit 17 to the chassis 102, the six mounting portions 1411 to 1416 provided on the upper frame portion 141 of the main frame 14 described above are used. Specifically, the first mounting location 1721 and the first mounting portion 1411 are overlapped in the vertical direction for mounting. The second mounting location 1722 and the second mounting portion 1412 are overlapped in the vertical direction for mounting. The third mounting location 1723 and the third mounting portion 1413 are overlapped in the vertical direction for mounting. The fourth mounting location 1724 and the fourth mounting portion 1414 are overlapped in the vertical direction for mounting. The fifth mounting location 1725 and the fifth mounting portion 1415 are overlapped in the vertical direction for mounting. The sixth mounting location 1726 and the sixth mounting portion 1416 are overlapped in the vertical direction for mounting. In each mounting pair, mounting (fastening) with vibration-proof measures using bolts, nuts, and vibration-proof rubber is performed.

[0062] Note that, as described above, the first leg portion 161a is attached to the first attachment portion 1411. For this purpose, on the first attachment portion 1411, the first leg portion 161a and the first attachment location 1721 are stacked in order from bottom to top, and the three stacked portions are fastened using bolts or the like. Similarly, the second leg portion 161b is attached to the third attachment portion 1413. For this purpose, on the third attachment portion 1413, the second leg portion 161b and the third attachment location 1723 are stacked in order from bottom to top, and the three stacked portions are fastened using bolts or the like. Further, the third leg portion 161c is attached to the fifth attachment portion 1415. For this purpose, on the fifth attachment portion 1415, the third leg portion 161c and the fifth attachment location 1725 are stacked in order from bottom to top, and the three stacked portions are fastened using bolts or the like. Also, the fourth leg portion 161d is attached to the sixth attachment portion 1416. For this purpose, on the sixth attachment portion 1416, the fourth leg portion 161d and the sixth attachment location 1726 are stacked in order from bottom to top, and the three stacked portions are fastened using bolts or the like. That is, the storage box (power unit) 161 is co-fastened to the main frame 14 together with the battery unit 17 in a state where anti-vibration measures are taken.

[0063] FIG. 12 is a schematic cross-sectional view showing a co-fastening structure of the storage box 161 and the battery unit 17 with respect to the main frame 14. FIG. 12 is a schematic cross-sectional view at the XII-XII position in FIG. 11. Specifically, it is a co-fastening structure in the third attachment portion 1413 of the main frame 14. Note that the co-fastening structures of the other portions are the same as the structure shown in FIG. 12.

[0064] As shown in FIG. 12, between the upper and lower directions of the head of the bolt 4 and the upper vibration isolator 7, the third mounting portion 1723 (a part of the left battery frame portion 172a) and the second leg portion 161b (a part of the storage box 161) that overlap vertically are sandwiched. Further, the third mounting portion 1413 (a part of the main frame 14) is sandwiched between the upper and lower vibration isolators 7 in the vertical direction. The portion on the side opposite to the head of the bolt 4 penetrates downward from the lower vibration isolator 7, and the washer 6 and the nut 5 are attached to the penetrated portion. When the bolt 4 and the nut 5 are tightened in this state, the third mounting portion 1723, the second leg portion 161b, and the third mounting portion 1413 are fastened in a state where vibration isolation measures are taken by the vibration isolator 7.

[0065] Note that for the parts that are not tightened together (for example, the mounting part for the second mounting portion 1412, etc.), the part corresponding to the second leg portion 161b shown in FIG. 12 disappears, but the other configurations are the same as the structure shown in FIG. 12. Also, in the above, there are 4 parts that are tightened together, but this number may be changed as appropriate. For example, tightening may be performed at all 6 fastening parts between the main frame 14 and the battery frame 172, or the number of parts tightened together may be less than 4 in this embodiment.

[0066] As can be understood from the above description, the main frame 14 supports the battery 171 via a vibration isolation portion (a specific example is the vibration isolator 7 shown in FIG. 12). The main frame 14 is a highly rigid part in the electric work vehicle 1. By attaching the battery 171 via the vibration isolation portion in such a place, the battery 171 can be made less susceptible to the influence of vehicle vibration, and the possibility of problems occurring in the battery 171 can be reduced.

[0067] In addition, the main frame 14 further supports at least one power electronics component (included in the power electronics unit 16). By supporting the battery 171 and the power electronics component on the same frame, the support structures of multiple components can be shared. And in this embodiment, the battery 171 and at least one power electronics component are attached to the main frame 14 using the same member. Specifically, "using the same member" means, in detail, "using the same bolts 4, nuts 5, and vibration isolators 7". In other words, the battery 171 and at least one power electronics component are clamped together to the main frame 14. With such a configuration, it is possible to prevent the battery 171 and the power electronics component from moving separately with respect to vehicle vibrations.

[0068] Specifically, since the battery unit 17 and the storage box (power electronics unit) 161 are clamped together in a vibration-isolated state using the same bolts 4, etc., relative movement between them can be suppressed. As a result, it is possible to suppress the harness connecting the battery 171 and the storage box 161 from bending or a large load being applied to the connector part, thereby improving the reliability of the power electronics system of the electric work vehicle 1.

[0069] Also, as shown in FIG. 11 etc., the main frame 14 supported by the traveling unit 13 supports the battery 171 and the electric motor 151. By attaching the traveling unit 13, the battery 171, and the electric motor 151 to the same frame, it is possible to share the components for support and make the electric work vehicle 1 more compact.

[0070] Also, as shown in FIG. 11, FIG. 4, etc., the electric motor 151 and the drive transmission unit 152 are arranged on one side of the battery 171. With such a configuration, the electric motor 151 and the drive transmission unit 152 can be arranged close to each other. As a result, the drive system mounted on the electric work vehicle 1 can be made more compact.

[0071] Then, as shown in FIG. 4 and the like, the electric motor 151 is disposed on one side rather than on the opposite side (the other side) of the end portion of the drive transmission portion 152. With such a configuration, a space can be created on the other side of the electric motor 151 to form a space for placing components such as frame members with a gap between the battery 171. Note that the end portion on the other side of the drive transmission portion 152 corresponds to the lower attachment portions 153a and 153b described above (see also FIG. 6).

[0072] Specifically, one side is the front side of the vehicle. That is, the electric motor 151 and the drive transmission portion 152 are disposed on the front side of the battery 171. The electric motor 151 is disposed on the front side rather than the rear end portion (the lower attachment portions 153a and 153b) of the drive transmission portion 152. Further, the electric work vehicle 1 has a work implement 3 disposed behind the battery 171 (see FIGS. 1 and 4). For this reason, in the electric work vehicle 1, the electric motor 151, the drive transmission portion 152, and the work implement 3 are disposed on opposite sides in the front-rear direction with the battery 171 interposed therebetween. As a result, heavy objects can be disposed at the front and rear portions of the electric work vehicle 1 to balance the front and rear.

[0073] FIG. 13 is a schematic plan view showing the relationship between the traveling portion 13 and the battery 171. Note that the battery 171 shown in FIG. 13 does not include the battery attachment piece 173 (see FIG. 10) for attachment to the battery frame 172. As shown in FIG. 13, the battery 171 is disposed inside the left and right end portions of the traveling portion 13. Specifically, the left end portion of the battery 171 is located to the right of the left end portion of the left crawler 13a. The right end portion of the battery 171 is located to the left of the right end portion of the right crawler 13b. With such a configuration, the amount by which the upper portion of the electric work vehicle 1 protrudes outward in the left-right direction with respect to the traveling portion 13 can be reduced, and the possibility of collision with obstacles existing on the side of the electric work vehicle 1 can be reduced.

[0074] In addition, in the present embodiment, the battery unit 17 protrudes outward in the left - right direction on both the left and right sides with respect to the traveling unit 13. However, this is an example, and the battery unit 17 may be configured to be arranged inside the left and right ends of the traveling unit 13. With such a configuration, the possibility that the upper part of the electric work vehicle 1 collides with an obstacle existing on the side of the electric work vehicle 1 can be reduced.

[0075] [2 - 6. Electrical component arrangement frame part] As shown in FIG. 3, the electrical component arrangement frame part 18 includes a sub - frame 181. In other words, the electric work vehicle 1 includes a sub - frame 181 arranged above the main frame 14. The sub - frame 181 supports various electrical components 182 arranged on the upper part of the electric work vehicle 1. The electrical components 182 are, in detail, electrical components driven by a low voltage (for example, 12V).

[0076] The power supply to the electrical components 182 is performed from the battery 171 via a DC - DC converter (not shown) included in the power electronics unit 16 and a low - voltage harness 183 which is a harness for low voltage. The low - voltage harness 183 is also supported by the sub - frame 181. In detail, not all of the low - voltage harness 183 is arranged on the sub - frame 181. Among the low - voltage harness 183, the main harness is arranged on the side of the chassis 102, and the harness bundling auxiliary wires connected to the electrical components 182 arranged on the upper part of the vehicle is supported by the sub - frame 181.

[0077] FIG. 14 is a perspective view showing a schematic configuration of the sub - frame 181. FIG. 15 is a schematic perspective view showing a state in which the sub - frame 181 is attached to the chassis 102. In FIG. 15, the power electronics unit 16 and the battery unit 17 are attached to the chassis 102.

[0078] The sub-frame 181 is fixed to the chassis 102. At least a part of the sub-frame 181 is disposed above the battery 171 and the electric motor 151. Specifically, the sub-frame 181 is attached to the chassis 102 so as to surround the upper part from the front of the chassis 102. In other words, the sub-frame 181 is attached to the chassis 102 so as to surround the traveling drive device 15, the power generation unit 16, and the battery unit 17.

[0079] The front and upper parts of the electric work vehicle 1 are the places where the load is first received during a collision or a rollover. Since the sub-frame 181 is provided at such a position, it is possible to guard against direct external force being applied to the battery 171, the electric motor 151, and the power generation unit 16 during a collision or a rollover. Although the sub-frame 181 may be damaged by such guarding, even in such a case, it is only necessary to replace the frame, which is an inexpensive part, and the maintainability can be improved.

[0080] In addition, in the present embodiment, the sub-frame 181 is covered from above by the exterior cover 12 (see FIG. 2 etc.). However, this is an example. At least a part of the sub-frame 181 may be disposed outside the exterior cover 12. For example, the upper part of the sub-frame 181 may protrude outside the exterior cover 12, and the sub-frame 181 may be used as a loading platform during material transportation. Thereby, the convenience of the electric work vehicle 1 can be improved.

[0081] The sub-frame 181 has a split structure (a structure that can be split). FIG. 16 is a diagram for explaining the split structure of the sub-frame 181. As shown in FIG. 16, the sub-frame 181 can be split into a vehicle upper frame part 181a, a vehicle front frame part 181b, and a vehicle lower frame part 181c.

[0082] The upper frame portion 181a of the vehicle has a pair of upper main frames 1810a and 1810b that are arranged at intervals in the left - right direction and extend in the front - rear direction. The pair of upper main frames 1810a and 1810b are connected by a plurality of upper connecting frames 1811 that extend in the left - right direction. At the front end of each of the pair of upper main frames 1810a and 1810b, upper front frames 1812a and 1812b that extend downward are provided. At the rear end of each of the pair of upper main frames 1810a and 1810b, upper rear frames 1813a and 1813b that extend downward are provided.

[0083] The front frame portion 181b of the vehicle has a front main frame 1814 in a U - shaped frame that extends obliquely rearward and has a portion that is bent in the middle and extends horizontally rearward. At the left and right rear ends of the front main frame 1814, intermediate connecting frames 1815 that connect the left and right rear ends are provided. At the left and right ends of the intermediate connecting frame 1815, intermediate connecting frame extension portions 1815a and 1815b that are bent downward are provided. Also, on the lower side portions that extend left and right of the front main frame 1814, rectangular front plate portions 1816 that spread downward are provided.

[0084] The lower frame portion 181c of the vehicle has a pair of lower main frames 1817a and 1817b that are L - shaped in a side view. At the front - side ends of the pair of lower main frames 1817a and 1817b, a lower first connecting frame 1818 that extends in the left - right direction and connects the two frames 1817a and 1817b is provided. At the rear - side ends of the pair of lower main frames 1817a and 1817b, a lower second connecting frame 1819 that extends in the left - right direction and connects the two frames 1817a and 1817b is provided.

[0085] The left and right upper front frames 1812a and 1812b are fastened to the intermediate connecting frame 1815 using fasteners (such as bolts and nuts), thereby connecting the upper vehicle frame portion 181a and the front vehicle frame portion 181b. The front plate portion 1816 is fastened to the lower first connecting frame 1818 using fasteners, thereby connecting the front vehicle frame portion 181b and the lower vehicle frame portion 181c.

[0086] Further, the sub-frame 181 formed by integrating the three frame portions 181a to 181c is attached to the main frame 14. Specifically, the lower end portions of the left and right upper rear frames 1813a and 1813b are fastened to the rear end surface of the upper frame portion 141 (see FIG. 3) of the main frame 14 using fasteners. Also, the left and right intermediate connecting frame extensions 1815a and 1815b are fastened to the upper surface of the front end portion of the main frame 14 using fasteners. Further, the lower second connecting frame 1819 is fastened to the front end surface of the lower frame portion 142 (see FIG. 3) of the main frame 14 using fasteners.

[0087] When the sub-frame 181 has a split structure as in this embodiment, the disassembly method of the sub-frame 181 can be selected according to the part to be maintained, and the workability during maintenance can be improved. For example, when it is desired to maintain the battery 171, the upper vehicle frame portion 181a of the sub-frame 181 may be disassembled, whereby the operator can easily access the battery 171.

[0088] FIG. 17 is a diagram for explaining an example of disassembling the electric work vehicle 1 during maintenance of the battery 171 such as battery replacement. In FIG. 17, the exterior cover 12 has already been removed. As shown in FIG. 17, during maintenance of the battery 171, together with the upper vehicle frame portion 181a of the sub-frame 181, the electrical components 182 and the low-voltage harness 183 attached to the upper vehicle frame portion 181a are also removed from the chassis 102.

[0089] The low-voltage harness 183 is provided with a connector 183a at a position where the sub-frame 181 can be divided. In accordance with the disassembly (division) of the sub-frame 181, the connector 183a is removed at the necessary locations. When the upper vehicle frame portion 181a is removed, the connector 183a disposed in the vicinity of the upper vehicle frame portion 181a and the front vehicle frame portion 181b is removed. Thereby, the low-voltage harness 183 attached to the upper vehicle frame portion 181a and the low-voltage harness 183 fixed to the main frame 14 and the front vehicle frame portion 181b can be easily disconnected.

[0090] Note that in the present embodiment, the battery unit 17 is configured to be disposed above the electric work vehicle 1. For this reason, simply by removing the upper vehicle frame portion 181a (including electrical components and the low-voltage harness), it becomes possible to easily access the battery 171. For this reason, if a replacement battery 171 is prepared, continuous work can be performed with less time loss without increasing the number of vehicles.

[0091] [2-7. Hydraulic Device (Hydraulic System)] The electric work vehicle 1 includes a hydraulic device 19 that constitutes a hydraulic system in a portion indicated by a broken line frame in FIG. 4 or in the vicinity thereof. The hydraulic device 19 is a device for raising and lowering the work implement 3. The elements constituting the hydraulic device 19 are concentrated and arranged at the rear part of the electric work vehicle 1 where the work implement 3 is provided. By configuring in this way, the oil passage can be shortened and the energy loss can be reduced. As a result, consumption of extra electric power can be suppressed and the time during which the electric work vehicle 1 can work can be lengthened.

[0092] The hydraulic device 19 includes at least a hydraulic cylinder and a hydraulic pump. The hydraulic pump is configured to be driven by a motor. The hydraulic device 19 preferably further includes a valve block having a relief valve. Also, the hydraulic device 19 preferably further includes a control valve. Also, the hydraulic device 19 preferably further includes a pipe (hydraulic pipe) through which oil flows.

[0093] In this embodiment, the hydraulic device 19 is disposed between the battery 171 and the traveling unit 13 and behind the power electronics component (power electronics unit 16). Further, the hydraulic device 19 is disposed below the electric motor included in the work implement drive device 111. With such a configuration, it is possible to configure such that electrical components such as power electronics components, the battery, and the electric motor are not disposed below the hydraulic device 19. As a result, even if oil leaks due to a failure of the hydraulic device 19, the possibility of the leaked oil adhering to the electrical components can be reduced. Since the possibility of a failure of the electrical components due to the adhesion of oil can be reduced, the possibility of a fatal defect such as inability to travel can be reduced.

[0094] In the traveling unit 13 composed of the left and right crawlers 13a and 13b, a gap is generated between the left and right crawlers 13a and 13b. A part of the hydraulic device 19 may enter this gap. Even in such a case, if a part of the hydraulic device 19 exists in the vertical direction between the lower end of the battery 171 and the upper end of the traveling unit 13, the hydraulic device 19 is regarded as existing between the battery 171 and the traveling unit 13.

[0095] <3. Details of Traveling Drive Device> Next, the traveling drive device 15 of the electric work vehicle 1 will be described in detail.

[0096] [3-1. Configuration of Traveling Drive Device] FIG. 18 is a perspective view showing a schematic configuration of the traveling drive device 15. FIG. 19 is a side view showing a schematic configuration of the traveling drive device 15. As shown in FIGS. 18 and 19, the traveling drive device 15 includes a traveling electric motor 151a, a turning electric motor 151b, a speed reducer 155, a connecting portion 156, an output end portion 157, and a brake portion 158.

[0097] Note that the traveling electric motor 151a and the turning electric motor 151b are included in the above-described electric motor 151. Also, the speed reducer 155, the connecting portion 156, and the output end portion 157 are included in the above-described drive transmission portion 152. Further, although a drive sprocket 132 is also shown in FIGS. 18 and 19, in the present embodiment, the drive sprocket 132 is a component of the traveling portion 13. However, the drive sprocket 132 may also be regarded as a component of the traveling drive device 15.

[0098] The traveling electric motor 151a generates traveling power. Specifically, the traveling power generated by driving the traveling electric motor 151a is transmitted to the output end portion 157 via power transmission elements included in the speed reducer 155 and the connecting portion 156. Details of this point will be described later. Also, the power source of the traveling electric motor 151a is the above-described battery 171 (see FIG. 3 etc.). Specifically, the traveling electric motor 151a is supplied with power from the battery 171 via an inverter (not shown) included in the power electronics unit 16.

[0099] The turning electric motor 151b generates turning power. Specifically, the turning power generated by driving the turning electric motor 151b is transmitted to the output end portion 157 via power transmission elements included in the speed reducer 155 and the connecting portion 156. Details of this point will be described later. Also, the power source of the turning electric motor 151b is the above-described battery 171. Specifically, the turning electric motor 151b is supplied with power from the battery 171 via an inverter included in the power electronics unit 16.

[0100] The speed reducer 155 is connected to the traveling electric motor 151a and the turning electric motor 151b. The speed reducer 155 includes a case 155a and a speed reduction mechanism 155b (see Fig. 20 etc.) provided inside the case 155a. That is, the traveling drive device 15 includes the speed reduction mechanism 155b. Specifically, the case 155a has a left case 155aL arranged on the left side and a right case 155aR arranged on the right side. Note that the pair of upper mounting portions 154a, 154b (see Fig. 6) described above are provided separately on the left case 155aL and the right case 155aR.

[0101] Fig. 20 is a perspective view showing a schematic configuration of the traveling drive device 15 with the right case 155aR removed. Fig. 21 is a perspective view showing a schematic configuration of the traveling drive device 15 with the case 155a removed. Fig. 21 is a view seen from the same direction as Fig. 20. Fig. 22 is a schematic perspective view of the traveling drive device 15 with the case 155a removed, seen from a direction different from Fig. 21.

[0102] As shown in Figs. 20 to 22, the speed reduction mechanism 155b has a left speed reduction mechanism 155bL arranged on the left side and a right speed reduction mechanism 155bR arranged on the right side. In this embodiment, the right speed reduction mechanism 155bR is the speed reduction mechanism of the traveling electric motor 151a, and the left speed reduction mechanism 155bL is the speed reduction mechanism of the turning electric motor 151b. However, the left and right positions of the traveling electric motor 151a and the turning electric motor 151b may be swapped, and accordingly, the positions of the left and right speed reduction mechanisms 155bL, 155bR may also be swapped. As will be described later, the left speed reduction mechanism 155bL and the right speed reduction mechanism 155bR share the final output shaft, and the outputs of both mechanisms 155bL, 155bR are integrated and output.

[0103] Each of the speed reduction mechanisms 155bL and 155bR is configured to include a plurality of power transmission elements. Specifically, the power transmission elements include gears. In addition to gears, the power transmission elements may include a chain or a belt. Details of the configurations of the speed reduction mechanisms 155bL and 155bR will be described later. Further, in the present embodiment, the traveling drive device 15 includes a differential mechanism 159 (see FIG. 24) that interlocks with the turning electric motor 151b. The differential mechanism 159 is also included in the case 155a, and this will also be described later.

[0104] The connecting portion 156 connects the speed reduction mechanism 155b and the output end portion 157 so as to be capable of power transmission. Specifically, the connecting portion 156 has a left connecting portion 156L disposed on the left side and a right connecting portion 156R disposed on the right side. That is, the output of the speed reduction mechanism 155b is taken out to the outside from two locations on the left and right. The connecting portions 156L and 156R each include a plurality of power transmission elements, and details of this will be described later.

[0105] The output end portion 157 is a portion that outputs the driving forces of the traveling electric motor 151a and the turning electric motor 151b to the outside of the device 15. Since the connecting portion 156 has the left and right connecting portions 156L and 156R, the output end portion 157 also has the left and right output end portions 157L and 157R. In the present embodiment, the left output end portion 157L is constituted by a part of the left connecting portion 156L. The right output end portion 157R is constituted by a part of the right connecting portion 156R. Details of this will be described later.

[0106] The brake portion 158 applies a brake to the power transmission elements included in the speed reduction mechanism 155b. The brake is a brake for maintaining the stopped state of the electric work vehicle 1 during parking. That is, the brake is a parking brake. Specifically, the brake maintains the stopped state of the vehicle when parked on an inclined surface. The brake portion 158 specifically applies a brake to the power transmission elements included in the right speed reduction mechanism 155bR provided corresponding to the traveling electric motor 151a. Details of the brake mechanism for operating the brake portion 158 will be described later.

[0107] [3-2. Details of Power Transmission] Next, the details of power transmission in the traveling drive device 15 will be described.

[0108] FIG. 23 is a power transmission system diagram of the traveling system. FIG. 24 is a power transmission system diagram of the turning system. As shown in FIGS. 23 and 24, a pair of left and right planetary speed change mechanisms 57L and 57R are commonly included in the power transmission systems of the traveling system and the turning system. The left and right planetary speed change mechanisms 57L and 57R constitute a differential mechanism 159 that interlocks with the turning electric motor 151b as will be understood from the following description.

[0109] The left and right planetary speed change mechanisms 57L and 57R are arranged symmetrically with respect to the sun shaft 56. The left and right planetary speed change mechanisms 57L and 57R each have a plurality (for example, three) of planetary gears 571. In the left planetary speed change mechanism 57L, each of the plurality of planetary gears 571 is rotatably supported by a planetary carrier 572 arranged on the left side. In the right planetary speed change mechanism 57R, each of the plurality of planetary gears 571 is rotatably supported by a planetary carrier 572 arranged on the right side. In each of the planetary speed change mechanisms 57L and 57R, the plurality of planetary gears 571 are located at the same radius around the sun shaft 56 and are arranged in mesh with sun gears 573 fixed to both left and right ends of the sun shaft 56.

[0110] In the left and right planetary speed change mechanisms 57L and 57R, ring gears 574 are respectively arranged concentrically with the sun shaft 56. Each ring gear 574 has internal teeth on its inner peripheral surface and external teeth on its outer peripheral surface. Each ring gear 574 is arranged in mesh with a plurality of planetary gears 571 with its internal teeth. Each ring gear 574 is rotatably supported via a bearing on the sun shaft 56 or on a center shaft 58 protruding outward in the left and right directions from the planetary carrier 572.

[0111] As shown in FIG. 23, the rotational power of the first motor shaft 51 protruding from the traveling electric motor 151a is transmitted from the output gear 52 of the first motor shaft 51 to the center gear 55 fixed to the sun shaft 56 via transmission gears 53 and 54. The rotational power transmitted to the center gear 55 is transmitted to a pair of left and right planetary speed change mechanisms 57L and 57R.

[0112] The rotational power transmitted to the left planetary speed change mechanism 57L is transmitted to the left bevel gear 59L fixed to the left end portion of the central axis 58 of the planetary carrier 572 via the planetary carrier 572. Similarly, the rotational power transmitted to the right planetary speed change mechanism 57R is transmitted to the right bevel gear 59R fixed to the right end portion of the central axis 58 of the planetary carrier 572 via the planetary carrier 572. Note that the central axis 58 of the planetary carrier 572 corresponds to the output shaft of the speed reducer 155 (differential mechanism 159 included in the speed reducer 155).

[0113] The rotational power transmitted to the left bevel gear 59L is transmitted to the relay shaft 60 included in the left connecting portion 156L and having bevel gears 61 fixed to both end portions thereof. The rotational power transmitted to the relay shaft 60 is transmitted to the external output shaft 62 having a bevel gear 63 fixed to one end portion (right end portion). The other end portion (left end portion) of the external output shaft 62 constitutes the left output end portion 157L, and the left drive sprocket 132 is attached to this portion.

[0114] Similarly, the rotational power transmitted to the right bevel gear 59R is transmitted to the relay shaft 60 included in the right connecting portion 156R and having bevel gears 61 fixed to both end portions thereof. The rotational power transmitted to the relay shaft 60 is transmitted to the external output shaft 62 having a bevel gear 63 fixed to one end portion (left end portion). The other end portion (right end portion) of the external output shaft 62 constitutes the right output end portion 157R, and the right drive sprocket 132 is attached to this portion.

[0115] As shown in FIG. 24, the rotational power of the second motor shaft 71 protruding from the swivel electric motor 151b is transmitted from the output gear 72 of the second motor shaft 71 to the center gear 80 fixed to the steering shaft 79 via a pair of transmission gears 73, 74 fixed to the first intermediate shaft 75 and a pair of transmission gears 76, 77 fixed to the second intermediate shaft 78. The rotational power transmitted to the steering shaft 79 via the center gear 80 is transmitted to a pair of left and right planetary speed change mechanisms 57L, 57R constituting the differential mechanism 159.

[0116] The transmission gear 81 attached to the left end side of the steering shaft 79 meshes with the external teeth of the ring gear 574 of the left planetary speed change mechanism 57L. For this reason, the rotational power transmitted to the steering shaft 79 is directly transmitted to the ring gear 574 of the left planetary speed change mechanism 57L. On the other hand, the transmission gear 82 attached to the right end side of the steering shaft 79 meshes with the reverse gear 84 attached to the reverse shaft 83, and this reverse gear 84 meshes with the external teeth of the ring gear 574 of the right planetary speed change mechanism 57R. For this reason, the rotational power transmitted to the steering shaft 79 is transmitted to the ring gear 574 of the right planetary speed change mechanism 57R after the rotational direction is reversed by the reverse gear.

[0117] For example, in a state where the rotation of the traveling electric motor 151a is stopped, the sun shaft 56 and the sun gears 573 on both the left and right sides are fixed. For this reason, when the swivel electric motor 151b rotates forward (or reversely), the left and right ring gears 574 rotate at the same rotational speed in opposite directions. Here, assume that the left ring gear 574 rotates forward and the right ring gear 574 rotates reversely. In this case, the left planetary gears 571 and the planetary carrier 572 rotate forward about the sun shaft 56, while the right planetary gears 571 and the planetary carrier 572 rotate reversely about the sun shaft 56. Therefore, the external output shaft 62 to which the rotational power is transmitted from the central shaft 58 of the left planetary carrier 572 via the relay shaft 60 rotates forward, and the external output shaft 62 to which the rotational power is transmitted from the central shaft 58 of the right planetary carrier 572 via the relay shaft 60 rotates reversely. Thus, the left crawler 13a moves forward and the right crawler 13b moves backward. In this case, the electric work vehicle 1 will spin turn to the right on the spot.

[0118] On the one hand, when the traveling electric motor 151a is rotated, as described above, the rotational power of the traveling electric motor 151a is transmitted to the sun shaft 56. If the rotation of the swivel electric motor 151b is stopped, the rotation of the ring gears 574 on both the left and right sides stops and becomes fixed. Therefore, the rotational power transmitted to the sun shaft 56 is equally transmitted to the left external output shaft 62 (left output end 157L) and the right external output shaft 62 (right output end 157R) via the left and right planetary speed change mechanisms 57L and 57R. As a result, the left and right drive sprockets 132 rotate in the same rotational direction at the same rotational speed, and the electric work vehicle 1 travels straight. That is, the electric work vehicle 1 moves forward or backward according to the rotational direction of the traveling electric motor 151a.

[0119] Based on the above principle, by appropriately combining and controlling the rotational speeds and rotational directions of the traveling electric motor 151a and the swivel electric motor 151b, the electric work vehicle 1 can be swiveled while traveling. Note that the rotational speeds and rotational directions of the traveling electric motor 151a and the swivel electric motor 151b can be adjusted by operating an operation unit composed of a lever or the like of the remote operation device 2 (see FIG. 1).

[0120] Here, referring to FIG. 23, the details of the brake unit 158 will be described. As shown in FIG. 23, the brake unit 158 is composed of an electromagnetic brake. Specifically, the brake unit 158 includes an electromagnetic unit 1581, a brake shaft 1582, and a brake gear 1583 fixed to the brake shaft 1582.

[0121] The electromagnetic unit 1581 switches between a state in which a brake is applied to the rotor 1581a that rotates together with the brake shaft 1582 and a state in which no brake is applied. When a brake is applied to the rotor 1581a, the rotation of the brake shaft 1582 and the brake gear 1583 becomes impossible. When the rotation of the brake gear 1583 becomes impossible, the transmission gear 53, which is the above-described power transmission element of the traveling system connected to the brake gear 1583 via the intermediate gear 65, also becomes non-rotatable. As a result, the left and right external output shafts 62 connected via the transmission gear 53 and a plurality of power transmission elements also become non-rotatable, and the stopped state of the electric work vehicle 1 during parking (standing still) is maintained. On the other hand, when no brake is applied to the rotor 1581a, the transmission gear 53 can rotate freely, so the brake unit 158 does not apply a brake to the traveling system of the electric work vehicle 1.

[0122] In the present embodiment, when the electromagnetic unit 1581 is energized, no brake is applied to the rotor 1581a, and when the energization in the electromagnetic unit 1581 is interrupted, a brake is applied to the rotor 1581a. By adopting such a configuration, it is possible to apply a brake without energization when the electric work vehicle 1 is parked. Further, when a failure occurs in the electrical system of the electric work vehicle 1 and the electric motor 151 stops operating, the electric work vehicle 1 can be safely stopped in a braked state. However, contrary to the configuration of the present embodiment, a configuration may be adopted in which a brake is applied to the rotor 1581a when the electromagnetic unit 1581 is energized, and no brake is applied to the rotor 1581a when the energization in the electromagnetic unit 1581 is interrupted.

[0123] Also, in the present embodiment, the intermediate gear 65 is configured to mesh with the transmission gear 53, but it is sufficient that the rotation of the traveling system can be stopped, and the gear with which the intermediate gear 65 meshes may be a gear fixed to another shaft. For example, the intermediate gear 65 may be configured to mesh with a gear fixed to the sun shaft 56. However, a configuration in which the intermediate gear 65 meshes with a gear fixed to a shaft disposed upstream of the speed reduction mechanism 155b (with a small torque) is preferable because a brake can be applied with a small force.

[0124] As can be understood from the above, in this embodiment, the intermediate gear 65 is disposed between the power transmission element of the speed reduction mechanism 155b and the brake unit 158. Specifically, the intermediate gear 65 is disposed between the power transmission element (gear 53) of the right speed reduction mechanism (speed reduction mechanism for the traveling system) 155bR and the brake gear 1583 of the brake unit 158.

[0125] If an attempt is made to configure a brake mechanism for maintaining the stopped state of the electric work vehicle 1 without using the intermediate gear 65, it becomes necessary to dispose the brake mechanism at the end of any shaft that performs power transmission in the traveling system. In this case, it is necessary to dispose the brake mechanism while avoiding the arrangement areas of the left and right electric motors 151a and 151b, and providing the brake mechanism tends to increase the size of the traveling drive device. In this regard, in the configuration in which the intermediate gear 65 is provided as in this embodiment, the brake mechanism can be configured with a smaller number of shafts with respect to the speed reduction mechanism 155b disposed between the left and right electric motors 151a and 151b. For this reason, the traveling drive device 15 having the brake mechanism can be configured compactly.

[0126] Also, if the left and right crawlers 13a and 13b are configured to be driven by separate electric motors, it becomes necessary to separately provide brake units (brake mechanisms) on the left and right output shafts (traveling drive shafts). On the other hand, in this embodiment, the number of the brake units 158 may be one, and the configuration of this embodiment can also be said to be an advantageous configuration in this regard.

[0127] [3-3. Layout of Each Part, etc.] Next, the layout and the like of each part constituting the traveling drive device 15 will be described.

[0128] As shown in FIG. 18, the speed reducer 155 is disposed between the traveling electric motor 151a and the turning electric motor 151b. In other words, the speed reduction mechanism 155b is disposed between the traveling electric motor 151a and the turning electric motor 151b (see also FIG. 21). By disposing the speed reduction mechanism 155b between the two electric motors 151a and 151b, the components (elements) constituting the speed reduction mechanism 155b can be concentrated and disposed near both electric motors 151a and 151b. For this reason, the traveling drive device 15 can be made more compact.

[0129] Specifically, the traveling electric motor 151a and the turning electric motor 151b are arranged side by side with a space therebetween in the left-right direction. That is, the traveling electric motor 151a and the turning electric motor 151b are arranged separately in the left-right direction with respect to the speed reduction mechanism 155b. Since the two electric motors 151a and 151b are arranged side by side in the left-right direction, the width of the traveling drive device 15 in the front-rear direction can be shortened.

[0130] More specifically, as shown in FIG. 22 and the like, the first motor shaft 51 connected to the speed reduction mechanism 155b of the traveling electric motor 151a and the second motor shaft 71 connected to the speed reduction mechanism 155b of the turning electric motor 151b are arranged on the same axis (on the first axis L1). Specifically, the first motor shaft 51 and the second motor shaft 71 are arranged on the same axis L1 extending in the left-right direction. Further, the first motor shaft 51 is, specifically, the output shaft of the traveling electric motor 151a and is connected to the right speed reduction mechanism 155bR. The second motor shaft 71 is, specifically, the output shaft of the turning electric motor 151b and is connected to the left speed reduction mechanism 155bL.

[0131] If the first motor shaft 51 and the second motor shaft 71 are arranged on the same axis L1, in the speed reducer 155 arranged between the two electric motors 151a and 151b, it is possible to support the two motor shafts 51 and 71 with the same member. Based on this point, in the present embodiment, as shown in FIGS. 20 to 22, the first motor shaft 51 and the second motor shaft 71 are rotatably held by a holding portion 1551 provided in a case 155a that covers the speed reduction mechanism 155b. The first motor shaft 51 and the second motor shaft 71 are rotatably held by the same (one) holding portion 1551. With such a configuration, the mounting structure of the output shafts of the two electric motors 151a and 151b can be simplified.

[0132] Specifically, the holding portion 1551 configured as one member is arranged inside the case 155a. The holding portion 1551 arranged inside the case 155a may be attached to either the left and right cases 155aL and 155aR. In the present embodiment, as shown in FIG. 20, the holding portion 1551 is attached to the left case 155aL.

[0133] FIG. 25 is a schematic cross-sectional view showing the support structure of the two motor shafts 51 and 71 by the holding portion 1551. The holding portion 1551 has a left concave portion 1551aL that is recessed rightward on the left side surface. Further, the holding portion 1551 has a right concave portion 1551aR that is recessed leftward on the right side surface. A bearing 1552 that rotatably supports the tip end portion (left end portion) of the first motor shaft 51 is arranged in the right concave portion 1551aR. Also, a bearing 1552 that rotatably supports the tip end portion (right end portion) of the second motor shaft 71 is arranged in the left concave portion 1551aL.

[0134] In this embodiment, the traveling drive device 15 is attached to the traveling unit 13 and the main frame 14. As can be understood from the above description, the attachment direction to these is the front-rear direction (see FIGS. 5 to 7). In the traveling drive device 15 having such an attachment direction, the brake unit 158 is disposed on one side in the front-rear direction of the speed reduction mechanism 155b. With such a configuration, as described above, the brake unit 158 can be disposed near the speed reduction mechanism 155b by using the intermediate gear 65. As a result, the traveling drive device 15 can be configured compactly.

[0135] Specifically, as shown in FIG. 19, the brake unit 158 is located forward of the first axis L1 of the traveling electric motor 151a and the turning electric motor 151b that are on the same axis as each other. Further, the second axis L2, which is the axis of the output shaft of the differential mechanism 159, is located forward of the first axis L1. With such a configuration, in the electric work vehicle 1, the traveling electric motor 151a and the turning electric motor 151b can be configured not to be at the foremost part. As a result, even if the electric work vehicle 1 collides with an obstacle, the electric motors 151a and 151b can be configured not to directly receive an external force. That is, even if it collides with an obstacle, the possibility of the high-voltage electric motors 151a and 151b malfunctioning can be suppressed to a low level. Note that the second axis L2 corresponds to the axis of the above-described central axis 58 (see FIG. 23).

[0136] Also, in this embodiment, in the traveling drive device 15 mounted on the electric work vehicle 1, the brake unit 158 is at the foremost part. For this reason, even if the electric work vehicle 1 collides with an obstacle, the possibility of the electric motors 151a and 151b and the speed reducer 155, which are behind the brake unit 158, malfunctioning can be suppressed. That is, even if it collides with an obstacle, the possibility of the drive system of the electric work vehicle 1 suffering a fatal failure that renders it unable to travel can be suppressed.

[0137] In addition, in the present embodiment, the first axis L1, the second axis L2, and the third axis L3 (see FIG. 19), which is the axis of the brake shaft 1582 of the brake unit 158, all extend in the left - right direction. As shown in FIG. 19, when viewed in plan (side view) from one side in the left - right direction, the third axis L3 is located between the first axis L1 and the second axis L2 in the direction in which the virtual line VL1 connecting the first axis L1 and the second axis L2 extends. With such a configuration, it is possible to suppress the brake unit 158 from protruding with respect to the two electric motors 151a, 151b and the differential mechanism 159, and the outer shape of the traveling drive device 15 can be made compact.

[0138] In addition, in the present embodiment, the height position of the output end portion 157 is further below the second axis L2, which is below the first axis L1. This is realized by the lower side of the traveling drive device 15 having a portal shape. The portal shape is realized by arranging bevel gears 59L, 59R (see FIG. 23) at the left and right ends of the output shaft (corresponding to the above - mentioned central shaft 58) of the speed reduction mechanism 155b (differential mechanism 159) and providing left and right connecting portions 156L, 156R.

[0139] By making the lower side of the traveling drive device 15 have a portal shape, in the electric work vehicle 1, the height positions of the electric motors 151a, 151b can be increased with respect to the output end portion 157 to which the drive sprocket 132 is attached. As a result, in the present embodiment, the electric motors 151a, 151b are at a higher position than the crawlers 13a, 13b. As a result, even if the left - right interval of the crawlers 13a, 13b is not widened, it is possible to avoid the two electric motors 151a, 151b arranged side by side in the left - right direction from contacting the crawlers 13a, 13b. Also, in a front view, the outer ends of the left and right electric motors 151a, 151b in the left - right direction can be configured not to protrude outward in the left - right direction with respect to the crawlers 13a, 13b. As a result, the electric work vehicle 1 can be made compact. Also, by making it a portal shape, it is possible to easily adjust the tread and the minimum ground clearance.

[0140] Note that the connecting portion 156 (left and right connecting portions 156L and 156R) specifically includes a first connecting portion 1561 and a second connecting portion 1562. The first connecting portion 1561 extends in the left-right direction, and one end thereof is connected to the output end portion 157. Specifically, the first connecting portion 1561 includes the external output shaft 62 (see FIG. 23) that extends in the above-described left-right direction. And the left-right outward end portion of the external output shaft 62 is directly connected to the output end portion 157. In other words, the left-right outward end portion of the external output shaft 62 constitutes the output end portion 157.

[0141] Also, the second connecting portion 1562 extends in a direction intersecting the left-right direction and is connected to the speed reduction mechanism 155b and the first connecting portion 1561. The second connecting portion 1562 includes the relay shaft 60 to which the bevel gears 61 are attached at both ends thereof. The relay shaft 60 is specifically the central shaft 58 that is the output shaft of the speed reduction mechanism 155b (differential mechanism 159), and is arranged in a direction orthogonal to the external output shaft 62. The relay shaft 60 is connected to be capable of power transmission with the central shaft 58 and the external output shaft 62 via the bevel gears 61 provided at both ends thereof.

[0142] With the connecting portion 156 configured in this way, the direction for transmitting the output of the speed reduction mechanism 155b (differential mechanism 159) to the output end portion 157 can be two directions. And by adopting such a two-direction configuration, it is easy to adjust the length in each direction according to the characteristics required for the electric work vehicle 1. For example, by adding a seat or extending the shaft, it is possible to expand in the left-right direction (tread direction) and in the height direction.

[0143] <4. Precautions, etc.> Various technical features disclosed in this specification can be variously modified without departing from the gist of the technical creation. Also, a plurality of embodiments and modification examples shown in this specification may be implemented in combination within the possible range.

[0144] <5. Supplementary Note> The exemplary electric work vehicle of the present invention includes a battery, an electric motor supplied with power from the battery, a traveling unit that travels by the driving force of the electric motor, and a drive transmission unit that transmits the driving force of the electric motor to the traveling unit. The electric motor and the drive transmission unit may be arranged on one side of the battery (first configuration).

[0145] In the electric work vehicle having the first configuration, the electric motor may be arranged on one side rather than at an end on the side opposite to the one side of the drive transmission unit (second configuration).

[0146] In the electric work vehicle having the first or second configuration, the one side may be the vehicle front side (third configuration).

[0147] In the electric work vehicle having any one of the first to third configurations, at least one power electronics component may be arranged between the battery and the traveling unit (fourth configuration).

[0148] In the electric work vehicle having the fourth configuration, the one side is the vehicle front side, and a work implement arranged behind the battery may be provided (fifth configuration).

[0149] In the electric work vehicle having the fifth configuration, a hydraulic device for raising and lowering the work implement may be arranged between the battery and the traveling unit and behind the power electronics component (sixth configuration).

[0150] In the electric work vehicle having any one of the first to sixth configurations, the battery may be arranged inside rather than at the left and right ends of the traveling unit (seventh configuration).

[0151] The electric work vehicle having any one of the first to seventh configurations includes a main frame supported by the traveling unit, and the main frame may be configured to support the battery and the electric motor (eighth configuration).

[0152] In the electric work vehicle having the eighth configuration, the main frame may be configured to support the battery via a vibration damping portion (ninth configuration).

[0153] In the electric work vehicle having the eighth or ninth configuration, the main frame may be configured to further support at least one power electronics component (tenth configuration).

[0154] In the electric work vehicle having the tenth configuration, the battery and the at least one power electronics component may be configured to be attached to the main frame using the same member (eleventh configuration).

[0155] In the electric work vehicle having any one of the eighth to eleventh configurations, the battery may be configured to be attached to the main frame via a battery frame that supports the battery (twelfth configuration).

[0156] The electric work vehicle having any one of the eighth to twelfth configurations includes a sub-frame disposed above the main frame, and at least a part of the sub-frame may be disposed above the battery and the electric motor (thirteenth configuration).

[0157] In the electric work vehicle having any one of the eighth to thirteenth configurations, the electric motor may be configured to be supported by the main frame and the traveling unit (fourteenth configuration).

Explanation of Reference Numerals

[0158] 1 ··· Electric work vehicle 3 ··· Working machine 7 ··· Vibration damping rubber (vibration damping portion) 13 ··· Traveling unit 14 ··· Main frame 19 ··· Hydraulic device 151 ··· Electric motor 152 ··· Drive transmission unit 171 ··· Battery 172 ··· Battery frame 181 ··· Sub-frame

Claims

1. A battery, an electric motor powered by the battery, a traveling unit that travels by the driving force of the electric motor, a drive transmission unit that transmits the driving force of the electric motor to the traveling unit, and comprising, wherein the electric motor and the drive transmission unit are arranged on one side of the battery, an electric work vehicle.

2. The electric work vehicle according to claim 1, wherein the electric motor is arranged on the one side rather than at an end on the opposite side of the one side of the drive transmission unit.

3. The electric work vehicle according to claim 2, wherein the one side is the front side of the vehicle.

4. The electric work vehicle according to claim 1, wherein at least one power electronics component is arranged between the battery and the traveling unit.

5. The one side is the front side of the vehicle, and the electric work vehicle according to claim 4, comprising a work implement arranged behind the battery.

6. The electric work vehicle according to claim 5, wherein a hydraulic device for raising and lowering the work implement is arranged between the battery and the traveling unit and behind the power electronics component.

7. The electric work vehicle according to claim 1, wherein the battery is arranged inside rather than at left and right ends of the traveling unit.

8. Comprising a main frame supported by the traveling unit, wherein the main frame supports the battery and the electric motor, the electric work vehicle according to claim 1.

9. The electric work vehicle according to claim 8, wherein the main frame supports the battery via a vibration damping portion.

10. The electric work vehicle according to claim 9, wherein the main frame further supports at least one power electronics component.

11. The electric work vehicle according to claim 10, wherein the battery and the at least one power electronics component are attached to the main frame using the same member.

12. The electric work vehicle according to claim 8, wherein the battery is attached to the main frame via a battery frame that supports the battery.

13. Comprising a sub-frame arranged above the main frame, wherein at least a part of the sub-frame is arranged above the battery and the electric motor, the electric work vehicle according to claim 8.

14. The electric work vehicle according to claim 8, wherein the electric motor is supported by the main frame and the traveling unit.

Images