Patent Description:
In recent years, in a view of a reduction in environmental load, even in a field of commercial vehicles, such as trucks, developed have been electric trucks that do not include an internal combustion engine, and are driven solely by an electric motor (see Patent Document <NUM>). Another example of electric truck is also provided in the Patent Document <NUM>.

As in the case with trucks using an internal combustion engine as a drive source, also in case of the electric trucks described above, there has been a demand to develop electric work vehicles having a mounted body, to be mounted on a vehicle body of a truck, enabling specific operations, such as a garbage vehicle, a freezing vehicle, a refrigeration vehicle, a dump truck vehicle, a mixer vehicle, a fire vehicle, and the like.

Such an electric work vehicle has an electric power take off (PTO) unit, including a motor, for supplying power to a mounted body. However, the PTO unit is usually added to an existing electric truck restricting it in terms of layout.

For example, in an electric truck, a component for driving the vehicle etc. is mounted in an under-cab region corresponding to an engine room in a truck using an internal combustion engine as a drive source, and a space in which the PTO unit is to be mounted is limited. Further, in a view of manufacturing cost, there is a demand that an electric work vehicle requiring a PTO unit and a common electric truck requiring a PTO unit share an identical mounting layout of electrical components.

Considering the limitation of layout of an under-cab region, it may also be conceivable to mount the PTO unit in a cab back space, between the cab and a cargo bed. However, in this case, to secure enough space in a cab back space for a large PTO unit, a front face of the cargo bed must be laid backward, which may disadvantageously result in reducing a length of the cargo bed, i.e. reducing load capacity.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric work vehicle capable of preventing reduction in the length of the cargo bed (load capacity) due to mounting the PTO unit while influence of change in layout of the under-cab region in case the PTO unit is mounted is reduced.

The present invention has been made to overcome at least some of the problems described above, and can be implemented as the following embodiments or application examples.

The mounted motor may be mounted without influencing the layout of the electrical component unit by disposing the mounted motor in a space in the lowermost layer region where the electrical component unit is disposed. Further, disposing a work machine drive unit, for driving a work machine of a mounted body, behind the mounted motor enables decrease in the distance between the work machine drive unit and the work machine, and reducing an influence on the layout on the side of the mounted body.

Thus, in a case in which the PTO unit, for driving the work machine drive unit by the mounted motor, is mounted, decrease in the length of the cargo bed (load capacity) resulting from mounting of the PTO unit may be prevented while influence of change in layout of the under-cab region is reduced.

The work machine drive unit may be modified into various work equipment in accordance with contents of a specific work of the mounted body. The mounted motor may be disposed in a space, which is a lowermost layer region and in which the electrical component unit is disposed, considering influence of change in layout of the under-cab region. However, if the water resistance of the devices is low, and the vehicle runs at a place where a water level is high, the devices may break. For this reason, the work machine drive unit requires higher water resistance. Accordingly, the devices cannot be freely selected.

However, according to the electric work vehicle of the present application example, the work machine drive unit is positioned behind the mounted motor and in a position higher than the height at which the mounted motor is mounted and disposed. Thus, the work machine drive unit requires lower water resistance. Hence, even devices having a relatively low water resistance may be selected.

In view of layout of the equipment, space between main frames, space between sub-frames and the like in the vicinity of a cab back space between the cab and the cargo bed are usually hardly to be utilized and are likely to become dead space. However, the electric work vehicle of the aspects stated above, has the work machine drive unit arranged in such the spaces. Thus, mounting the PTO unit does not make influence of change in layout of the under-cab region. Further, it is possible to mount the PTO unit without increase of the cab back space between the cab and the cargo bed, in contrast with a case when the whole PTO unit is to be mounted in the cab back space.

Embodiments of the present invention will be now described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following description and can be implemented within the scope of the present invention as defined in the appended claims.

Further, all the drawings used in the description of the embodiments schematically illustrate components. For ease of understanding, the drawings may be partially emphasized, enlarged, constricted, or omitted and they may not precisely illustrate the scale or the state or the components.

<FIG> is a side view of an electric work vehicle <NUM> according to a first embodiment of the present invention. The electric work vehicle <NUM> is an electric work vehicle for performing a specific operation, and the vehicle includes a vehicle body <NUM> as a driving component, a mounted body <NUM> mounted on the vehicle body <NUM>, and a PTO unit <NUM> driving the mounted body <NUM>. In the present embodiment, the electric work vehicle <NUM> will be described as a freezing vehicle, but the vehicle may be any other work vehicle such as a garbage vehicle, a dump truck vehicle, a mixer vehicle, a fire vehicle, a crane vehicle, or the like.

The vehicle body <NUM> includes a main frame <NUM>, a battery <NUM>, a running driving unit <NUM>, wheels <NUM>, and a cab <NUM>.

The main frame <NUM> is a frame that support, in addition to the cab <NUM> and the mounted body <NUM>, further heavy load to be mounted on the vehicle body <NUM>. The battery <NUM> is a power supply source that supplies electric power necessary for running and driving the vehicle body <NUM> and driving electric equipment mounted on the electric work vehicle <NUM>. As will be described later in detail, the running driving unit <NUM> converts the electric power supplied from the battery <NUM> into running power of the vehicle body <NUM> and transmits the electric power thus converted to the wheels <NUM>. The wheels <NUM> are suspended on the main frame <NUM> and include a front wheel 14F provided below the cab <NUM> in the vehicle height direction (Z direction in the figure) and a rear wheel 14R driven by the running driving unit <NUM>. The cab <NUM> is a structure including a driver seat and the like, and is provided in a front portion of the main frame <NUM> in the vehicle longitudinal direction (X direction in the figures).

In the present embodiment, the mounted body <NUM> is a mounted system for a freezing vehicle, and includes a freezing loading unit <NUM>, a freezer <NUM>, and sub-frames <NUM>.

The freezing loading unit <NUM> is a structure onto which cargo or the like transported by the electric work vehicle <NUM> is loaded and in which the cargo or the like is frozen by keeping the inside of the unit at a low temperature. The freezer <NUM> is a work machine for freezing, and includes a freezing capacitor, and cools the inside of the freezing loading unit <NUM> by supplying refrigerant. The sub-frames <NUM> are disposed behind the cab <NUM> and interposed between the upper side of the main frame <NUM> and the freezing loading unit <NUM>. Each of the sub-frames <NUM> is a support member supporting and fixing the freezing loading unit <NUM> indirectly to the main frame <NUM>.

The PTO unit <NUM> converts the electric power supplied from the battery <NUM> into rotational power and drives the freezer <NUM> of the mounted body <NUM>. In the present embodiment, the PTO unit <NUM> has a mounted motor <NUM> that is rotatably driven by the electric power of the battery <NUM>, and a compressor <NUM> (work machine drive unit) that is driven by transmitting the rotational power of the mounted motor <NUM> via a belt <NUM>, as will be described in detail later. As the compressor <NUM> is rotatably driven, the refrigerant is supplied to the freezer <NUM>. More specifically, the PTO unit <NUM> circulates refrigerant to the freezer <NUM> through a refrigerant circuit 30a arranged along a surface of the freezing loading unit <NUM> that faces the cab <NUM>.

Next, the configuration of the vehicle body <NUM> will be described in more detail. <FIG> is a perspective view illustrating the configuration of the vehicle body <NUM> and the PTO unit <NUM>. More specifically, <FIG> is a perspective view of the electric work vehicle <NUM> viewed obliquely from a left rear side with the mounted body <NUM> removed.

The main frame <NUM> includes a left main frame <NUM> and a right main frame 11R that are paired. The left main frame <NUM> and the right main frame 11R extend in the vehicle longitudinal direction X of the electric work vehicle <NUM> and are disposed in parallel to each other in the vehicle width direction Y. The left main frame <NUM> and the right main frame 11R are connected by a plurality of cross members <NUM> (only one shown in <FIG>) which extend in the vehicle width direction Y and constitute a so-called ladder frame. Although not illustrated in <FIG>, the sub-frames <NUM> also extend in the vehicle longitudinal direction X, and includes a left sub-frame <NUM> disposed on the left main frame <NUM>, and a right sub-frame 23R disposed on the right main frame 11R.

As described above, the battery <NUM> is a secondary battery that supplies electric power necessary for running and driving the vehicle body <NUM> and driving the electric equipment. The battery <NUM> includes a plurality of battery modules (not shown) relatively large in size and having relatively large capacity in order to store the electric power required for both the vehicle body <NUM> and the electric equipment. Further, the battery <NUM> is configured to be capable of supplying electric power independently to the front and to the rear in the vehicle longitudinal direction X.

The battery <NUM> of the present embodiment has two integral portions: a portion formed into a roughly cuboid shape and disposed between the left main frame <NUM> and the right main frame 11R in the vehicle width direction Y; and a portion formed into a roughly cuboid shape and disposed below the main frame <NUM> in the vehicle height direction Z. The battery <NUM> has a cross-sectional shape of an inverted T taken along a plane perpendicular to the vehicle longitudinal direction X. The battery <NUM> is arranged such that the left main frame <NUM> and the right main frame 11R pass by a step portion formed due to a difference in a width of the two upper and lower portions. Accordingly, the battery <NUM> effectively utilizes the space below the mounted body <NUM>, thereby increasing the battery capacity. Note that the shape of the battery <NUM> is not limited to the example stated above and may be changed depending on the required battery capacity and layout of the vehicle body <NUM> as appropriate.

The battery <NUM> is elastically suspended on the main frame <NUM> by a plurality of battery support members 12a from outside in the vehicle width direction Y. Further, the battery <NUM> is provided with a power distribution unit 12b serving as an "output terminal" in a front region in the vehicle longitudinal direction X. The power distribution unit 12b supplies electric power to the PTO unit <NUM> and an electrical component unit <NUM>, which will be described later, via a high-voltage cable 12c.

More specifically, the power distribution unit (PDU) 12b distributes electric power from the battery <NUM> to each element of the electric equipment including the PTO unit <NUM> and the electrical component unit <NUM>. In the present embodiment, the power distribution unit 12b is provided between the left main frame <NUM> and the right main frame 11R, in the vehicle width direction Y, and on a front outer surface of the battery <NUM> in the vehicle longitudinal direction X. Note that the position of the power distribution unit 12b is not limited to the example stated above. For instance, the power distribution unit 12b may be installed in the center portion of the upper surface of the battery <NUM>, or independently, in a position spaced away from the front outer surface of the battery <NUM>, to the front in the vehicle longitudinal direction X. In this case, the power distribution unit 12b is connected to the main body of the battery <NUM> through wiring. In addition, the power distribution unit 12b may be provided on a front interior surface inside a housing of the battery <NUM> in the vehicle longitudinal direction X. The high-voltage cable 12c may be extended from a front outer surface of the housing of the battery <NUM> in the vehicle longitudinal direction X.

The running driving unit <NUM> includes a running inverter 13a, a running motor 13b, and a speed reducer 13c, and converts electric power supplied from the battery <NUM> into running power for the vehicle body <NUM>, as described above. More specifically, the running driving unit <NUM> converts DC power supplied from the battery <NUM> into AC power suitable for a proper running as appropriate, and supplies the AC power to the running motor 13b. Then, the speed reducer 13c decelerates the rotational power generated in the running motor 13b. Then, the vehicle body <NUM> is run by driving the rear wheel 14R via a differential and a rear axle.

Here, although not illustrated, the cab <NUM> has its front end lower portion vertically rotatably supported on the main frame <NUM>, and forms a tiltable cab mount structure. A rear end lower portion of the cab <NUM> is supported by an elastic support member (not shown) in an inverted U-shaped cab bridge <NUM> that is provided to bridge the left main frame <NUM> and the right main frame 11R.

Referring to <FIG> and <FIG>, <FIG> is a cross-sectional view taken along the line A-A of <FIG>, and <FIG> is a cross-sectional view taken along the line B-B of <FIG>.

As shown in <FIG> and <FIG>, an under-cab region <NUM> corresponding to an engine room in a conventional cab-over engine truck is formed below a lower surface 15a of the cab <NUM>. Further, as shown in <FIG>, a cab back space <NUM> is formed between a back surface 15b of the cab <NUM> and the front surface of the mounted body <NUM>, i.e., the front surface 21a of the freezing loading unit <NUM>. In the present embodiment, the PTO unit <NUM> and the electrical component unit <NUM> are accommodated in a space reaching from an under-cab region <NUM> to the cab back space <NUM>.

Specifically, in the under-cab region <NUM>, an electrical component support member <NUM>, having a multilayered structure, is provided on the main frames <NUM> that are paired. The electrical component support member <NUM> includes a plurality of support members. Each main frame <NUM> has a base plate <NUM> attached on the internal side in the vehicle width direction. The base plate <NUM> is provided with support props <NUM>, each extending upward in the vehicle height direction Z. In the upper portion of the support props <NUM>, an upper beam <NUM> extends in the vehicle width direction Y between the left support prop and the right support prop. Below the upper beam <NUM> in the vehicle height direction Z, a middle beam <NUM> extends in the vehicle width direction Y between the left support prop and the right support prop. Further, lower brackets <NUM> are provided at the front and the back in a lower portion of each base plate <NUM>. A bottom plate <NUM> is supported by each lower bracket <NUM> via dampers <NUM>. As described above, the electrical component support member <NUM> has a three-layer structure consisting of a top level, a middle level, and a bottom level.

The electrical component unit <NUM> is provided in the top level and the middle level of the electrical component support member <NUM>. The electrical component unit <NUM> consists of one or more electrical components mainly for driving the vehicle. The electrical component unit <NUM> includes: for example, a high-voltage inverter <NUM> converting DC power, supplied via the high-voltage cable 12c from the power distribution unit 12b, into AC power; a DC-DC converter <NUM> converting DC power, from the battery <NUM> for driving, into low-voltage; and a control unit <NUM> that performs various controls of the vehicle. The high-voltage inverter <NUM> is connected to the mounted motor <NUM> via wiring 12d. Note that the type of electrical component is not limited to this example, and these electrical components may be not equipped, or another electrical component may be included.

Further, the bottom plate <NUM> (a motor support member) corresponding to the bottom level of the electrical component support member <NUM> is disposed at a position lower than the main frame <NUM>. The mounted motor <NUM> of the PTO unit <NUM> is provided on the right side in the vehicle width direction Y from the center on the top of the bottom plate <NUM>. That is, the mounted motor <NUM> is disposed at the lowest position of the electrical component support member <NUM>. The mounted motor <NUM> is elongated in the vehicle longitudinal direction X, and has the output shaft extending rearward. A motor-side pulley 31a is attached to the output shaft.

The compressor <NUM> of the PTO unit <NUM> is disposed in the cab back space <NUM>. Specifically, a support plate <NUM> (drive unit support member) extending in the vehicle width direction and is stretched between the left and right main frames <NUM> that are paired. The compressor <NUM> is provided on the left side viewed from the center in the vehicle width direction Y on the top of the support plate <NUM>. The length of the compressor <NUM> in the vehicle longitudinal direction X fits in the cab back space <NUM> and is located in front of the freezing loading unit <NUM> and the sub-frames <NUM> of the mounted body <NUM>.

A compressor-side pulley 33a is provided on an input shaft of the compressor <NUM>. The belt <NUM> is wound around the compressor-side pulley 33a and the motor-side pulley 31a such that the rotational power of the mounted motor <NUM> can be transmitted to the compressor <NUM> via the belt <NUM>.

In the electric work vehicle <NUM> configured as described above, electric power of the battery <NUM> is supplied to the mounted motor <NUM> through the high-voltage inverter <NUM> of the electrical component unit <NUM>, and is converted into the rotational power by the mounted motor <NUM>. The rotational power generated by the mounted motor <NUM> is transmitted to the compressor <NUM> via the belt <NUM>. Thereafter, the refrigerant is supplied to the freezer <NUM> through the refrigerant circuit 30a by driving of the compressor <NUM>. The operation is then executed by the freezer <NUM>.

As described above, the mounted motor <NUM> may be mounted in the under-cab region <NUM> of the electric work vehicle <NUM> of the first embodiment of the present invention while influence the layout of the electrical component unit <NUM> is reduced, by disposing the mounted motor <NUM> of the PTO unit <NUM> in the lowermost layer region of the space where the electrical component unit <NUM> is disposed. Further, disposing the compressor <NUM> for driving the freezer <NUM> of the mounted body <NUM> behind the mounted motor <NUM> in the vehicle longitudinal direction X enables decrease in the distance between the compressor <NUM> and the freezer <NUM>, as well as reduction in influence on the layout on the side of the mounted body <NUM>.

Thus, in case of mounting the PTO unit <NUM> for driving the compressor <NUM> by the mounted motor <NUM>, the risk of decrease in the length of the cargo bed (load capacity) resulting from mounting of the PTO unit <NUM> may be prevented while influence of change in layout of the under-cab region <NUM> is reduced.

Further, the mounted motor <NUM> is arranged such that its output shaft is directed rearward. Accordingly, even a mounted motor <NUM> that is long in the axial direction can be easily disposed in the under-cab region <NUM> regardless of the interval between the left and right main frames <NUM>.

In addition, the space in which the electrical component unit <NUM> is disposed has a multilayered structure including the plurality of electrical component support members on which the electrical component unit <NUM> is mounted and supported. The mounted motor <NUM> is disposed on the bottom plate <NUM> which is an electrical component support member constituting the bottom surface of the multilayered structure. Thereby, the mounted motor <NUM> may be mounted without influencing the layout of the electrical component unit <NUM> and the mounted body <NUM>.

Further, the compressor <NUM> is disposed higher than the mounted motor <NUM>. Accordingly, the water resistance required for the compressor <NUM> becomes lower. Hence, even a device having a relatively low water resistance may be selected.

Furthermore, the compressor <NUM> is arranged on the main frame <NUM> via the support plate <NUM> between the cab <NUM> and the mounted body <NUM> in the cab back space <NUM> in the vehicle longitudinal direction X. Accordingly, the compressor <NUM> may be mounted while influence on the layout of the electrical component unit <NUM> and the mounted body <NUM> is reduced. Further, the compressor is arranged at a position higher than the main frame <NUM>, which may reduce the influence of stones and water, bouncing from the ground, on the compressor <NUM>. Therefore, the layout of the PTO unit <NUM> like that of the present embodiment is suitable particularly in a case in which a work machine drive unit has lower durability and waterproof properties than a mounted motor and the like.

A second embodiment of the present invention will be now described. A PTO unit <NUM> of an electric work vehicle <NUM> of the present invention is different from the PTO unit <NUM> of the electric work vehicle <NUM> of the foregoing first embodiment. Hereinafter, parts different from those of the first embodiment will be described. Components common to those of the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

<FIG> is a side view of the electric work vehicle <NUM> of the second embodiment of the present invention. <FIG> is a cross-sectional view taken along line C-C of <FIG>, and <FIG> is a cross-sectional view taken along line D-D of <FIG>.

The electric work vehicle <NUM> according to the second embodiment illustrated in <FIG> is a garbage work vehicle including a mounted body <NUM> for driving a garbage work machine <NUM> with hydraulic pressure. The garbage work vehicle includes a PTO unit <NUM>. The PTO unit <NUM> transmits the rotational power of a mounted motor <NUM> to a hydraulic pump <NUM> via a gearbox <NUM> and drives the garbage work machine <NUM> with the hydraulic pressure generated by the hydraulic pump <NUM>.

Specifically, as shown in <FIG> and <FIG>, in an under-cab region <NUM>, as in the first embodiment, an electrical component support member <NUM> having a multilayered structure is provided on main frames <NUM> that are paired, and an electrical component unit <NUM> is provided in a top level and a middle level of the electrical component support member <NUM>.

The mounted motor <NUM> of the PTO unit <NUM> is provided on a top of a bottom plate <NUM> corresponding to a bottom level of the electrical component support member <NUM>. That is, also in the second embodiment, the mounted motor <NUM> is disposed at the lowest position in the electrical component support member <NUM>. The mounted motor <NUM> is elongated in a vehicle longitudinal direction X. The output shaft of the mounted motor <NUM> extends rearward, and the gearbox <NUM> is attached to the output shaft. The gearbox <NUM> is configured to convert rotational power from the mounted motor <NUM>, via a plurality of internal gears, into the number of revolutions and the torque suitable for the hydraulic pump <NUM> to output them to the coupling shaft <NUM> coupled with the hydraulic pump <NUM>.

The hydraulic pump <NUM> of the PTO unit <NUM> is disposed in a cab back space <NUM>. Specifically, a coupling plate 59a extends rearward from a bottom plate <NUM> supporting the mounted motor <NUM>, and a pump support bracket 59b is set upright from the rear end of the coupling plate 59a. The hydraulic pump <NUM> has its front surface coupled to the pump support bracket 59b and is thus supported by the pump support bracket 59b via the coupling plate 59a from the bottom plate <NUM>. The hydraulic pump <NUM> extends, in the vehicle longitudinal direction X, from the cab back space <NUM> to a front of sub-frames <NUM> supporting the mounted body <NUM>. The hydraulic pump <NUM> is positioned closer to the right side than the center in the vehicle width direction Y. The hydraulic pump <NUM> is disposed higher than the mounted motor <NUM> in the vehicle height direction Z, and extends from the main frame <NUM> to the sub-frames <NUM>. The hydraulic pump <NUM> is connected to the garbage work machine <NUM> via a hydraulic circuit (not shown), and the hydraulic pressure generated by the driving of the hydraulic pump <NUM> is supplied to the garbage work machine <NUM>.

As described above, also in the electric work vehicle <NUM> according to the second embodiment, the mounted motor <NUM> may be mounted without influencing the layout of the electrical component unit <NUM> by arranging the mounted motor <NUM> of the PTO unit <NUM> lower than the electrical component unit <NUM>, in the under-cab region <NUM>. Further, the hydraulic pump <NUM> for driving the garbage work machine <NUM> of the mounted body <NUM> is disposed behind the mounted motor <NUM> in the vehicle longitudinal direction X, which enables decrease in the distance between the hydraulic pump <NUM> and the garbage work machine <NUM>, and reduction in influence on the layout on the side of the mounted body <NUM>.

Thus, in case of mounting the PTO unit <NUM> for driving the compressor <NUM> by the mounted motor <NUM>, it is possible to reduce the risk of decrease in the length of the cargo bed (load capacity) resulting from mounting the PTO unit <NUM> while influence of change in layout of the under-cab region <NUM> is reduced.

In addition, the same advantages as those of the first embodiment can be achieved. Further, the hydraulic pump <NUM> of the second embodiment is disposed between the left and right main frames <NUM>, which are paired, and between the sub-frames <NUM>. In view of layout of the equipment, space between main frames, space between sub-frames and the like in the vicinity of a cab back space are usually hardly to be utilized and are likely to become dead space. However, in the electric work vehicle <NUM> of the present embodiment, the hydraulic pump <NUM> is arranged in such a space. Thus, mounting the PTO unit <NUM> does not make influence of change in layout of the under-cab region <NUM>. Further, it is possible to mount the PTO unit <NUM> without increase of the cab back space <NUM>, in contrast with a case when the whole PTO unit <NUM> is to be mounted in the cab back space <NUM>.

The mounted motor <NUM> is supported by the bottom plate <NUM> coupled to the main frame <NUM>. The hydraulic pump <NUM> is supported by the coupling plate 59a, which is coupled to the bottom plate <NUM>, and the pump support bracket 59b. In this way, the mounted motor <NUM> and the hydraulic pump <NUM> are supported on the coupled support member, which enables alleviating the deviation due to vibration between the mounted motor <NUM> and the hydraulic pump <NUM>, and more reliably transmitting the rotational power of the mounted motor <NUM> to the hydraulic pump <NUM>.

Although the detailed description of the embodiments of the present invention has been described above, the aspect of the present invention is not limited to the foregoing embodiments but solely by the appended claims.

In the foregoing embodiments, the battery <NUM> is disposed between the left and right main frames <NUM> that are paired. However, the battery may be disposed at an outer side of the main frame in the vehicle width direction.

Claim 1:
An electric work vehicle that includes a mounted body enabling execution of a specific work and is capable of running by electric power supplied from a battery, the electric work vehicle comprising:
left and right main frames that are paired and extend in a vehicle front-rear direction;
a cab provided in a front portion of the main frame in the vehicle front-rear direction;
an electrical component unit disposed on the main frame in a position lower than a lower surface of the cab; and
a PTO unit having a work machine drive unit for driving a work machine to execute the specific work by the mounted body, and a mounted motor for supplying rotational power, by electric power of the battery, to the work machine drive unit, wherein
in the PTO unit, the mounted motor is in a position lower than the lower surface of the cab and in a lowermost layer region of a space where the electrical component unit is disposed, and the work machine drive unit is disposed in a position rearward from the mounted motor.