Patent Description:
As an example of a working vehicle, a hydraulic excavator, a track loader, and the like including a lower body to which driving crawlers or tires are mounted, an upper body provided on the lower body, and a working unit that is mounted to the lower body or the upper body and that works by a hydraulic pressure are known.

Recently, a working vehicle driven by an electric motor instead of a conventional engine is under development. In the electrification of the working vehicle, it is important to thermally control on-board devices (refer to <CIT>). <CIT> discloses an electric excavator having the features in the preamble of claim <NUM>. <CIT> discloses further prior art.

In the working vehicle described above as an example, improved cooling efficiency is attained by partitioning a vehicle body interior into an electrical device chamber where electrical devices are accommodated and a hydraulic device chamber where hydraulic devices are accommodated, and separately providing a cooling system dedicated to cool the electrical devices and a cooling system dedicated to cool the hydraulic devices. As for device cooling, it is necessary to actuate the cooling system at a reference temperature matched to the device with the lowest heat resistance in each device chamber. However, with mere categorization into the electrical devices and the hydraulic devices, a proper temperature zone wildly fluctuates among the devices, resulting in difficulty in controlling the cooling systems and failure to achieve efficient cooling. As a result, availability factors of the cooling systems tend to rise, leading to an increase in power consumption and the generation of noise from the cooling systems (such as fans).

The present invention has been accomplished under the solutions as disclosed below. An object of the present invention is to provide a working vehicle capable of improving cooling efficiency and achieving reduced power consumption and suppressed noise.

The present invention solves the problems by the following solutions.

A working vehicle having a vehicle body, a travel unit, a working unit working by a hydraulic pressure, and an electric motor that serves as a drive source for the travel unit or the working unit, includes: a first device chamber provided in a front portion of the vehicle body; a second device chamber provided in a rear portion of the vehicle body; a first partition that partitions the first device chamber from surroundings inside the vehicle body; and a second partition that partitions the second device chamber from the surroundings inside the vehicle body, the first device chamber including devices that generate heat and that become relatively high temperature or have relatively high heat resistance, the device including a hydraulic pump that supplies hydraulic oil to the travel unit or the working unit; an electric motor that drives the hydraulic pump; and an inverter that controls a driving voltage of the electric motor, the second device chamber including devices that generate heat and that do not become relatively high temperature or have relatively low heat resistance, the device including an on-board charger that supplies electric power for driving the electric motor; a battery pack having a rechargeable battery that stores the electric power supplied from the on-board charger; a converter that converts an output voltage of the battery pack; and a controller, and the first device chamber and the second device chamber being cooled by separate cooling fans, respectively.

According to the configurations, ranges of the proper temperature zones of the devices provided in the device chambers can be reduced, facilitating the management of the reference temperatures (that is, cooling fan control). Therefore, improved cooling efficiency, reduced power consumption, and suppressed noise caused by the cooling fans can be achieved. Furthermore, isolating the first device chamber and the second device chamber by the partitions can prevent heat generated in the first device chamber from being transferred to the second device chamber. Therefore, it is possible to prevent heat damage to devices with low heat resistance.

Furthermore, the first device chamber has a first air inlet in the front portion of the vehicle body and a first air outlet in one side portion of the vehicle body.

It is also preferable that the second device chamber has a second air inlet in the other side portion of the vehicle body and a second air outlet in the one side portion of the vehicle body, and includes a third partition that partitions the on-board charger disposed at a position closer to the second air inlet from the battery pack disposed at a position farther from the second air inlet.

Furthermore, it is preferable that the vehicle body includes a counterweight that is provided in the rear portion and that maintains a balance during slewing, that the counterweight has a third air inlet at a position closer to the second air inlet, and that the battery pack is cooled by outside air taken in mainly from the third air inlet.

Moreover, it is preferable that the second device chamber includes an oil cooler proximate to the second air outlet, that the counterweight has a fourth air inlet at a position closer to the second air outlet, and that the oil cooler is cooled by the outside air taken in from the second air inlet, the third air inlet, and the fourth air inlet.

According to the present invention, it is possible to improve the cooling efficiency of the working vehicle. Therefore, it is possible to realize the reduced power consumption and the suppressed noise.

Embodiments of the present invention will be described hereinafter in detail with reference to the drawings. <FIG> and <FIG> are schematic diagrams (a perspective view from upper rear left and a perspective view from upper right front) illustrating an example of a working vehicle <NUM> according to an embodiment of the present invention. For the sake of convenience of description, arrows may indicate up and down, front and back, and left and right directions in the drawings. In addition, members having the same function are denoted by the same reference sign and may not be repeatedly described in all the drawings for describing the embodiments.

A hydraulic excavator will be described as an example of the working vehicle <NUM> according to the present embodiment. However, the working vehicle <NUM> is not limited to the hydraulic excavator.

As illustrated in <FIG> and <FIG>, the working vehicle <NUM> includes, as a vehicle body, a lower body <NUM> and an upper body <NUM> provided on the lower body <NUM>. The upper body <NUM> is slewed by an electric slew motor (not illustrated). It is noted that the lower body <NUM> and the upper body <NUM> of the working vehicle <NUM> may be configured as one piece.

The lower body <NUM> includes a travel unit <NUM> that travels. The lower body <NUM> includes a pair of left and right crawlers (tracks) <NUM> as an example of the travel unit <NUM>. However, the travel unit <NUM> is not limited to the crawlers <NUM>. As another example, the working vehicle <NUM> may include tires (not illustrated) instead of the crawlers <NUM>. The crawlers <NUM> are each driven (to travel) by a hydraulic travel motors <NUM>.

The working vehicle <NUM> includes working units <NUM> and <NUM> mounted to the lower body <NUM> or the upper body <NUM> and worked by a hydraulic pressure (hydraulic oil at a predetermined pressure).

The working vehicle <NUM> includes a blade <NUM> as an example of the working unit <NUM>. The blade <NUM> is mounted to the lower body <NUM> in such a way as to be able to swing upward and downward (including forward and backward components). The blade <NUM> is driven by a hydraulic cylinder (blade cylinder) <NUM>. However, the working unit <NUM> is not limited to the above configurations.

The working vehicle <NUM> includes a boom <NUM>, an arm <NUM>, and an attachment (a bucket in the present embodiment) <NUM> as an example of the working unit <NUM>. However, the attachment <NUM> is not limited to the bucket. The boom <NUM> is mounted to the upper body <NUM> in such a way as to be able to swing upward and downward (including forward and backward components). In the present embodiment, a boom bracket <NUM> is provided between the upper body <NUM> and the boom <NUM>. The boom bracket <NUM> enables the boom <NUM> to swing to left and right (including forward and backward components) in relation to the upper body <NUM>. It is noted that the boom bracket <NUM> may be omitted. The arm <NUM> is mounted to the boom <NUM> in such a way as to be able to swing upward and downward (including forward and backward components). The attachment <NUM> is mounted to the arm <NUM> in such a way as to be able to swing upward and downward (including forward and backward components). The boom <NUM> is driven by a hydraulic cylinder (boom cylinder) <NUM>. The arm <NUM> is driven by a hydraulic cylinder (arm cylinder) <NUM>. The attachment <NUM> is driven by a hydraulic cylinder (bucket cylinder) <NUM>. However, the working unit <NUM> is not limited to the above configurations.

A driving mechanism for driving the hydraulic travel motors <NUM> and the hydraulic cylinders is configured from hydraulic pumps (to be described later in detail) driven by a drive source, a control valve (not illustrated), and the like. The control valve is actuated by an operator operating the operating units to exercise control to supply hydraulic oil at a predetermined pressure delivered from the hydraulic pumps to the hydraulic travel motors <NUM> and the hydraulic cylinders. This allows for the travel unit <NUM> to travel and for the working units <NUM> and <NUM> to work. In the present embodiment, the working vehicle <NUM> includes electric motors (to be described later in detail) as the drive source.

The working vehicle <NUM> also includes an on-board charger <NUM> that supplies electric power to the electric motors. The electric power output from the on-board charger <NUM> is supplied to the electric motors via a battery pack <NUM> and inverters (to be described later in detail). The battery pack <NUM> includes a first rechargeable battery (e.g., lithium-ion rechargeable battery) that stores the supplied electric power, a control section controlling the supply of the electric power to the electric motors and the rechargeable battery (first rechargeable battery), and the like (all of which are not illustrated). A second rechargeable battery (e.g., lead-acid rechargeable battery) and switches (controllers) are connected to the battery pack <NUM> (all of which are not illustrated).

Configurations of the upper body <NUM> will next be described in detail. The upper body <NUM> includes a main body frame <NUM> that is provided in a lower portion and that serves as both a reinforcement member and a support member for the on-board devices. The main body frame <NUM> is formed from plates, beams, and the like worked into predetermined shapes and welded integrally. The upper body <NUM> includes a cab <NUM> provided in a front left portion and in which operating units for an operator to operate traveling and working are provided. In the present embodiment, an air conditioner for air-conditioning an interior of the cab <NUM> is provided.

The upper body <NUM> includes a counterweight <NUM> that is provided in a rear portion and that maintains a balance during slewing. The upper body <NUM> includes a hydraulic oil tank <NUM> provided in a right central portion and storing hydraulic oil. The upper body <NUM> includes exterior covers (a right side cover <NUM>, a left side cover <NUM>, and a battery cover <NUM>) covering devices on board the main body frame <NUM>. The cab <NUM>, the counterweight <NUM>, and the hydraulic oil tank <NUM> are mounted to the main body frame <NUM>. The exterior covers are mounted to a floor frame (not illustrated).

As illustrated in <FIG>, the upper body <NUM> includes a first device chamber <NUM> in a front portion (to the right of the cab <NUM> and in front of the hydraulic oil tank <NUM>). The first device chamber <NUM> is partitioned from the surroundings inside the upper body <NUM> by a first partition <NUM> constituted from a partition plate <NUM> built on the main body frame <NUM> and a front surface 22a of the hydraulic oil tank <NUM>. An upper portion of the first device chamber <NUM> is covered with the right side cover <NUM>. The upper body <NUM> includes a second device chamber <NUM> in a rear portion (in the rear of the cab <NUM> and the hydraulic oil tank <NUM>). The second device chamber <NUM> is partitioned from the surroundings inside the upper body <NUM> by a second partition <NUM> constituted from a partition plate <NUM> built on the main body frame <NUM> and a rear surface 22b of the hydraulic oil tank <NUM>. An upper portion of the second device chamber <NUM> is covered with the left side cover <NUM> and the battery cover <NUM>.

First, the first device chamber <NUM> will be described (refer to <FIG>). In the first device chamber <NUM>, devices that generate heat when the working vehicle <NUM> operates and that become relatively high temperature or have relatively high heat resistance (hereinafter, "in a high proper temperature zone") are provided. Specifically, the first device chamber <NUM> includes a first hydraulic pump <NUM> and a second hydraulic pump <NUM>. The first device chamber <NUM> includes a first electric motor <NUM> and a second electric motor <NUM>. The first device chamber <NUM> includes a first inverter <NUM>, a second inverter <NUM>, a third inverter <NUM>, and a fourth inverter <NUM>. The first device chamber <NUM> includes an air conditioner compressor <NUM> and a mini electric motor <NUM>.

The first electric motor <NUM> and the second electric motor <NUM> are mounted to be aligned upward and downward on an electric motor bracket <NUM>. The first electric motor <NUM> drives the first hydraulic pump <NUM>. The second electric motor <NUM> drives the second hydraulic pump <NUM>.

The first hydraulic pump <NUM> is mounted to a rear portion of the first electric motor <NUM>. The second hydraulic pump <NUM> is mounted to a rear portion of the second electric motor <NUM>. The first hydraulic pump <NUM> and the second hydraulic pump <NUM> draw in the hydraulic oil stored in the hydraulic oil tank <NUM> and supply (pump) the hydraulic oil to the travel unit <NUM> or the working units <NUM> and <NUM>.

The first inverter <NUM>, the second inverter <NUM>, the third inverter <NUM>, and the fourth inverter <NUM> are mounted to the partition plate <NUM>. The first inverter <NUM> controls a driving voltage of the first electric motor <NUM>. The second inverter <NUM> controls a driving voltage of the second electric motor <NUM>. The third inverter <NUM> controls a driving voltage of the electric slew motor. The fourth inverter <NUM> controls a driving voltage of the mini electric motor <NUM>.

The air conditioner compressor <NUM> is provided above the electric motor bracket <NUM>.

The mini electric motor <NUM> is mounted to a front portion of the air conditioner compressor <NUM>. The mini electric motor <NUM> drives the air conditioner compressor <NUM>.

The first device chamber <NUM> has a first air inlet <NUM> in a front portion of the upper body <NUM> (right side cover <NUM>). One or a plurality of first air inlets <NUM> are provided. The first device chamber <NUM> has a first air outlet <NUM> in a right side portion of the upper body <NUM> (right side cover <NUM>). One or a plurality of first air outlets <NUM> are provided.

The first device chamber <NUM> includes cooling fans <NUM> and <NUM>. The cooling fans <NUM> and <NUM> are provided to be aligned upward and downward in the front portion (in front of the first air inlet <NUM>). The cooling fan <NUM> is a normally driven main fan. The cooling fan <NUM> is a sub-fan operating in an auxiliary manner depending on an operational status of the working vehicle <NUM>. The cooling fan <NUM> may be omitted.

Cooling air (outside air) is taken in the first device chamber <NUM> via the first air inlet <NUM> by rotating the cooling fans <NUM> and <NUM>. The cooling air taken in flows in the first device chamber <NUM> along the first partition <NUM> and cools the devices in the first device chamber <NUM>. The cooling air heated up after absorbing heat from the devices is discharged outside the first device chamber <NUM> via the first air outlet <NUM>.

Next, the second device chamber <NUM> will be described (refer to <FIG>, <FIG>). In the second device chamber <NUM>, devices that generate heat when the working vehicle <NUM> operates and that do not become relatively high temperature or have relatively low heat resistance (hereinafter, "in a low proper temperature zone") are provided. Specifically, the second device chamber <NUM> includes the on-board charger <NUM>, the battery pack <NUM>, a converter <NUM>, and a controller <NUM>.

The second device chamber <NUM> also includes an oil cooler <NUM> and an air conditioner condenser <NUM>.

The on-board charger <NUM> is provided in a left portion of the second device chamber <NUM> (at a position closer to a second air inlet <NUM> (to be described later in detail)). The on-board charger <NUM> supplies electric power for driving the electric motors <NUM>, <NUM>, and the like.

The battery pack <NUM> is provided in a central portion of the second device chamber <NUM> (at a position farther from the second air inlet <NUM>). The battery pack <NUM> is partitioned from the on-board charger <NUM>, the converter <NUM>, and the controller <NUM> inside the second device chamber <NUM> by a third partition <NUM> constructed from partition plates <NUM> and <NUM>. The partition plate <NUM> is provided between the on-board charger <NUM> and the battery pack <NUM>. The partition plate <NUM> is provided above the battery pack <NUM>. The battery pack <NUM> stores electric power supplied from the on-board charger <NUM>.

The converter <NUM> is mounted on the partition plate <NUM>. The converter <NUM> converts an output voltage of the battery pack <NUM>.

The controller <NUM> is located to the left of the converter <NUM> and mounted on the partition plate <NUM>. The controller <NUM> exercises a plurality of controls, including controls over the operation of the working vehicle <NUM> (such as slewing by the electric slew motor, traveling by the travel unit <NUM>, working by the working units <NUM>, <NUM>, and running of the air conditioner for air-conditioning the interior) and controls over the supply of the electric power to the on-board devices. It is noted that these controls may be performed by a plurality of controllers (not illustrated).

The oil cooler <NUM> is provided in a right portion (at a position proximate to a second air outlet <NUM>). The oil cooler <NUM> cools the hydraulic oil returned from the travel unit <NUM> and the working units <NUM> and <NUM>.

The air conditioner condenser <NUM> is provided below the oil cooler <NUM>.

The second device chamber <NUM> has the second air inlet <NUM> in a left side portion of the upper body <NUM> (left side cover <NUM>). One or a plurality of second air inlets <NUM> are provided. The second device chamber <NUM> has the second air outlet <NUM> in a right side portion of the upper body <NUM> (right side cover <NUM>) (at a position rearward of the first air outlet <NUM>). One or a plurality of second air outlets <NUM> are provided.

The second device chamber <NUM> includes cooling fans <NUM> and <NUM>. The cooling fan <NUM> is mounted to the left of the oil cooler <NUM>. The cooling fan <NUM> is mounted to the left of the air conditioner condenser <NUM>. It is noted that the cooling fan <NUM> is a cooling fan that mainly cools the air conditioner condenser <NUM>.

Cooling air (outside air) is taken in the second device chamber <NUM> via the second air inlet <NUM> by rotating the cooling fans <NUM> and <NUM>. The cooling air taken in flows in the second device chamber <NUM> along the second partition <NUM> and the third partition <NUM> and cools the devices in the second device chamber <NUM>. Specifically, the cooling air cools the on-board charger <NUM> first, the controller <NUM> next, the converter <NUM> next, and then the oil cooler <NUM> and the air conditioner condenser <NUM>. The cooling air heated up after absorbing heat from the devices is discharged outside the second device chamber <NUM> via the second air outlet <NUM>.

Here, the heated cooling air does not flow to the battery pack <NUM> since the battery pack <NUM> is partitioned (shielded) by the third partition <NUM>. This can inhibit a temperature rise of the battery pack <NUM>, which is particularly vulnerable to heat.

A rear portion of the battery pack <NUM> is covered with the counterweight <NUM>. The counterweight <NUM> has a third air inlet <NUM> in a left portion (at a position closer to the second air inlet <NUM>). The counterweight <NUM> has a fourth air inlet <NUM> in a right portion (at a position closer to the second air outlet <NUM>).

The battery pack <NUM> is cooled by cooling air taken in via the third air inlet <NUM>. The cooling air taken in resolves the stagnation of heat generated from the battery pack <NUM>. This can prevent heat damage to the battery pack <NUM>.

The oil cooler <NUM> and the air conditioner condenser <NUM> are cooled by not only the cooling air taken in via the second air inlet <NUM> but also the cooling air taken in via the third air inlet <NUM> and the fourth air inlet <NUM>. The cooling air taken in is discharged outside the second device chamber <NUM> via the second air outlet <NUM>. This can efficiently cool the oil cooler <NUM> and the air conditioner condenser <NUM>.

As described so far, the working vehicle <NUM> according to the present embodiment includes: the first device chamber <NUM> provided in the front portion of the upper body <NUM>; and the second device chamber <NUM> provided in the rear portion of the upper body <NUM>, the devices in the high proper temperature zone are provided in the first device chamber <NUM>, the devices in the low proper temperature zone are provided in the second device chamber <NUM>, and the first device chamber <NUM> and the second device chamber <NUM> are cooled separately by the cooling fan <NUM> (<NUM>) and the cooling fan <NUM> (<NUM>), respectively. This can reduce ranges of the proper temperature zones of the devices provided in the device chambers <NUM> and <NUM>, facilitating the management of the reference temperatures (that is, cooling fan control). Therefore, improved cooling efficiency, reduced power consumption, and suppressed noise caused by the cooling fans can be achieved. Furthermore, isolating the device chambers <NUM> and <NUM> by the partitions <NUM> and <NUM> can prevent heat generated in the first device chamber <NUM> from being transferred to the second device chamber <NUM>. Therefore, it is possible to prevent heat damage to devices with low heat resistance.

Moreover, the working vehicle <NUM> according to the present embodiment has the first air inlet <NUM> in the front portion of the upper body <NUM> and the second air inlet <NUM> in the left side portion of the upper body <NUM>. The working vehicle <NUM> has the first air outlet <NUM> and the second air outlet <NUM> in the right side portion of the upper body <NUM>. That is, the air inlets <NUM> and <NUM> are provided facing the vehicle body surface where the air outlets <NUM> and <NUM> are provided or are provided on the other side surface of the vehicle body surface; therefore, fresh cooling air (that is, cooling air at outside air temperature) can always be taken in the first device chamber <NUM> and the second device chamber <NUM>. Therefore, the cooling efficiency can be improved.

As described so far, according to the present invention, the working vehicle capable of realizing improved cooling efficiency can be provided.

While the working vehicle mounting the two hydraulic pumps that configure the driving mechanism has been described as an example of the working vehicle <NUM>, the working vehicle <NUM> may mount one or three or more hydraulic pumps depending on configurations, loads, and the like of the working units <NUM> and <NUM> and the travel unit <NUM>. Furthermore, the number of electric motors that configure the drive source may be changed as appropriate depending on the number, rated output power, and the like of the hydraulic pumps.

While the working vehicle mounting the air conditioner in the cab <NUM> for air-conditioning the interior of the cab <NUM> has been described as an example of the working vehicle <NUM>, the working vehicle <NUM> may be configured without the air conditioner. In that case, the air conditioner compressor <NUM>, the mini electric motor <NUM>, the fourth inverter <NUM>, the air conditioner condenser <NUM>, and the cooling fan <NUM> are omitted.

Claim 1:
A working vehicle (<NUM>) having:
a vehicle body (<NUM>);
a travel unit (<NUM>);
a working unit (<NUM>, <NUM>) working by a hydraulic pressure; and
an electric motor (<NUM>, <NUM>) that serves as a drive source for the travel unit (<NUM>) or the working unit (<NUM>, <NUM>), wherein
the working vehicle (<NUM>) comprises:
a first device chamber (<NUM>) provided in a front portion of the vehicle body (<NUM>);
a second device chamber (<NUM>) provided in a rear portion of the vehicle body (<NUM>);
a first partition (<NUM>) that partitions the first device chamber (<NUM>) from surroundings inside the vehicle body (<NUM>); and
a second partition (<NUM>) that partitions the second device chamber (<NUM>) from the surroundings inside the vehicle body (<NUM>), wherein
the first device chamber (<NUM>) and the second device chamber (<NUM>) are separately cooled by different fans (<NUM>, <NUM>), respectively, wherein
the first device chamber (<NUM>) comprises
devices that generate heat and that become relatively high temperature or have relatively high heat resistance, the device including:
a hydraulic pump (<NUM>, <NUM>) that supplies hydraulic oil to the travel unit (<NUM>) or the working unit (<NUM>, <NUM>);
an electric motor (<NUM>, <NUM>) that drives the hydraulic pump (<NUM>, <NUM>); and
an inverter (<NUM>, <NUM>) that controls a driving voltage of the electric motor (<NUM>, <NUM>), characterized in that
the second device chamber (<NUM>) comprises
devices that generate heat and that do not become relatively high temperature or have relatively low heat resistance, the device including:
an on-board charger (<NUM>) that supplies electric power for driving the electric motor (<NUM>, <NUM>);
a battery pack (<NUM>) having a rechargeable battery that stores the electric power supplied from the on-board charger (<NUM>);
a converter (<NUM>) that converts an output voltage of the battery pack (<NUM>); and
a controller (<NUM>), and wherein
the first device chamber (<NUM>) has a first air inlet (<NUM>) in the front portion of the vehicle body (<NUM>) and a first air outlet (<NUM>) in one side portion of the vehicle body (<NUM>).