Patent Description:
In recent years, a construction machine such as a hydraulic excavator sees increasing demands for a hybrid construction machine equipped with an engine and an electric motor for a drive source, and an electric-drive construction machine equipped with an electric motor for a drive source, due to consideration to environment and restrictions on workplaces. In an electric-drive construction machine, electric power is supplied from a commercial power source to an electric motor using a cable, or electric power is supplied to an electric motor from batteries placed on a machine-body frame of the electric-drive construction machine (see, for example, <CIT>).

From <CIT> an electric work vehicle is known, comprising a plurality of batteries stored in a at least partially welded shelf-like member, which together form a battery unit that is mounted on a revolving superstructure. <CIT> discloses an electric construction machine comprising a battery device that is mounted on a vehicle rear part by means of a flange. Furthermore, <CIT> discloses a construction machine having a battery fixing device that is formed by a battery platform, which is fixed to the revolving frame using a J-bolt and hooking construction. From <CIT> a further battery holding structure of a battery-driven construction machine is known. Furthermore, <CIT> discloses a battery connected to a revolving frame, wherein connection cables are suspended by an adjacent inverter.

From <CIT> an electric work vehicle is known, comprising a plurality of batteries stored in a shelf-like member, which together form a battery unit that is mounted on a revolving superstructure. <CIT> discloses an electric construction machine comprising a battery device that is mounted on a vehicle rear part by means of a flange. Furthermore, <CIT> discloses a construction machine having a battery fixing device that is formed by a battery platform, which is fixed to the revolving frame using a J-bolt and hooking construction. From <CIT> a further battery holding structure of a battery-driven construction machine is known.

However, since a machine-body frame, to which batteries are fixed, is formed by welding a metal material such as a steel plate, the portion to which the batteries are fixed may be distorted by welding. In such a case, local high stresses are caused in the batteries when the batteries are fixed to the machine-body frame, and thus there is a risk that the batteries may be damaged.

An object of the present invention that has been made in view of the above-mentioned fact is to provide a construction machine capable of preventing damages to batteries placed on a machine-body frame.

For solving the above-mentioned problem, the present invention provides a construction machine as follows. That is, the present invention provides a construction machine comprising a machine-body frame, a supporting plate installed on the machine-body frame via elastic mounts, and batteries fixed to a topside of the supporting plate, wherein welding is not performed on the supporting plate, i.e. each of the supporting plates is free of welds.

The construction machine comprises a shelf having a plurality of shelf plates, which is arranged at intervals in an up-down direction and is installed on a rear end portion of the machine-body frame, wherein a plurality of the supporting plates is provided and installed on respective topsides of the plurality of shelf plates via the elastic mounts. The shelf is preferably installed on the rear end portion of the machine-body frame via additional elastic mounts. It is convenient to comprise a cover member that covers upper part, rear part, and side part of the shelf. Base plates are preferably fixed to the rear end portion of the machine-body frame, and the supporting plates are installed on topsides of the base plates via the elastic mounts. Also, electrical components other than the batteries are preferably fixed to the topsides of the supporting plates.

In a construction machine of the present invention, since a supporting plate to which batteries are fixed is installed on the machine-body frame via elastic mounts, the effect of distortion of the machine-body frame on the supporting plate is reduced, by the elastic mounts located between the machine-body frame and the supporting plate, even if the machine-body frame is distorted by welding. Further, since welding is not performed on the supporting plate that supports the batteries, distortion due to welding is not caused in the supporting plate. Therefore, in the construction machine of the present invention, it is possible to suppress generation of local high stresses in the batteries and prevent damages to the batteries.

Hereinbelow, a preferred embodiment of a construction machine configured in accordance with the present invention will be described with reference to the drawings, taking an electric-drive hydraulic excavator provided with an electric motor for a drive source as an example.

When giving a description with reference to <FIG>, the whole of an electric-drive hydraulic excavator denoted by reference numeral <NUM> comprises a lower traveling structure <NUM>, an upper revolving structure <NUM> supported in a freely revolvable manner by the lower traveling structure <NUM>, and a working arm device <NUM> installed on the upper revolving structure <NUM>.

The working arm device <NUM> includes a boom <NUM> (a base end thereof is connected to the upper revolving structure <NUM>), an arm <NUM> (a base end thereof is connected to a tip end of the boom <NUM>), and a bucket <NUM> connected to a tip end of the arm <NUM>, a boom cylinder <NUM> that swings the boom <NUM> with respect to the upper revolving structure <NUM>, an arm cylinder <NUM> that swings the arm <NUM> with respect to the boom <NUM>, and a bucket cylinder <NUM> that swings the bucket <NUM> with respect to the arm <NUM>. Then, in the electric-drive hydraulic excavator <NUM>, various works such as excavating work are adapted to be performed by swinging the boom <NUM>, the arm <NUM>, and the bucket <NUM> of the working arm device <NUM> by respective cylinders <NUM>, <NUM>, and <NUM>.

On a frame <NUM> (hereinafter referred to as "machine-body frame <NUM>") of the upper revolving structure <NUM>, mounted are a cab <NUM>, an electric motor (not shown) as a drive source, and a hydraulic pump (not shown) connected to an output shaft of the electric motor. The machine-body frame <NUM> is formed by welding an appropriate metal material such as a steel plate. In the electric-drive hydraulic excavator <NUM>, high pressure hydraulic oil is adapted to be suppled from the hydraulic pump to the hydraulic actuators such as the boom cylinder <NUM>, by driving the hydraulic pump by the electric motor.

As shown in <FIG>, a shelf <NUM> that accommodates a plurality of batteries <NUM> for supplying electric power to the electric motor is arranged at the rear end portion of the machine-body frame <NUM>. As the batteries <NUM>, for example, a lithium ion battery can be used. When giving a description with reference to <FIG>, the shelf <NUM>, which can be formed by welding an appropriate metal material such as a steel material, includes a top plate <NUM> extending substantially horizontally, a plurality of (four in the illustrated embodiment) shelf plates <NUM> arranged at intervals in an up-down direction below the top plate <NUM>, and a connecting member <NUM> for connecting the top plate <NUM> and the plurality of shelf plates <NUM>. Respective shelf plates <NUM> are arranged substantially horizontally, and the lowermost shelf plate <NUM> is fixed to the rear end portion of the machine-body frame <NUM> by a plurality of bolts <NUM> (see <FIG>).

The connecting member <NUM> of the illustrated embodiment, as shown in <FIG>, has a pair of side plates <NUM> extending downward from both ends in a width direction of the top plate <NUM>, and a plurality (<NUM> in the illustrated embodiment) of partition plates <NUM> arranged between the top plate <NUM> and the shelf plates <NUM> and between neighboring shelf plates <NUM> in an up-down direction between the pair of side plates <NUM>. One side plate <NUM> is welded to one end portion in the width direction of the top plate <NUM> and one end portions in the width direction of respective shelf plates <NUM>, and the other side plate <NUM> is welded to the other end portion in the width direction of the top plate <NUM> and to the other end portions in the width direction of respective shelf plates <NUM>. As can be understood by referring to <FIG>, lower end portions of respective partition plates <NUM> are welded to topsides of the shelf plates <NUM>, and upper end portions of respective partition plates <NUM> are welded to an underside of the top plate <NUM> or undersides of the shelf plates <NUM>.

When giving a description with reference to <FIG>, a plurality of elastic mounts <NUM> is fixed to the topsides of respective shelf plates <NUM>. The elastic mount <NUM> may have a known configuration, but the elastic mount <NUM> of the illustrated embodiment has a lower plate <NUM> made of metal in a diamond shape fixed to the topside of the shelf plate <NUM> with bolts <NUM>, a rubber <NUM> in a column shape anchored to a topside of the lower plate <NUM>, and an upper plate <NUM> made of metal in a diamond shape anchored to a topside of the rubber <NUM>. Nuts <NUM> are welded to an underside of the upper plate <NUM>.

As shown in <FIG>, supporting plates <NUM> in a rectangular shape are arranged substantially horizontally above respective shelf plates <NUM>, and the supporting plates <NUM> are each installed to the elastic mounts <NUM>, by fastening the bolts <NUM> and the nuts <NUM> of the elastic mounts <NUM>. That is, a plurality of the supporting plates <NUM> is provided and installed on respective topsides of the shelf plates <NUM> via the elastic mounts <NUM>. The respective supporting plates <NUM> are formed of an appropriate metal material such as a steel plate. On the supporting plates <NUM>, drilling for forming a hole through which the bolt <NUM> is passed and a tapping for forming a female thread are performed, but welding is not performed.

As can be understood by referring to <FIG>, in the illustrated embodiment, the plurality of batteries <NUM> is fixed to the topsides of respective supporting plates <NUM> by bolts <NUM>. The number of batteries <NUM> to be fixed to respective supporting plates <NUM> may be one. Further, the fixing of the batteries <NUM> to the supporting plates <NUM> is not limited to the bolts <NUM>, and although not shown, for example, recesses may be formed on side surfaces of the batteries <NUM>, and fixtures formed with protrusions configured to fit into the recesses of the batteries <NUM> may be adapted to be attached to the supporting plates <NUM>.

In a case where the plurality of batteries <NUM> is fixed to one sheet of the supporting plate <NUM> as shown in the illustrated embodiment, each interval between neighboring batteries <NUM> can be made smaller than a case where one battery <NUM> is fixed to one supporting plate <NUM>, and therefore, the plurality of batteries <NUM> is preferably fixed to one supporting plate <NUM>. In a case where one battery <NUM> is fixed to one supporting plate <NUM>, when the batteries <NUM> swing with respect to the shelf plates <NUM> due to vibration generated when the electric-drive hydraulic excavator <NUM> travels, for example, the plurality of batteries <NUM> will make different movements respectively. For this reason, it is necessary to make the interval between the neighboring batteries <NUM> relatively large to prevent the neighboring batteries <NUM> from interfering with each other. On the other hand, when the plurality of batteries <NUM> is fixed to one sheet of the supporting plate <NUM>, the batteries <NUM> fixed to the same supporting plate <NUM> make the same movement, so that the neighboring batteries <NUM> do not interfere with each other, and thus the interval between the neighboring batteries <NUM> can be made relatively small.

Any electrical component other than the batteries <NUM> may be fixed to the topsides of the supporting plates <NUM>. In the illustrated embodiment, as shown in <FIG>, battery disconnect units <NUM> are fixed to the topsides of the supporting plates <NUM>. Each of the battery disconnect units <NUM> includes a contactor, a fuse, a current measuring instrument, a device (none of which is shown) that acquires information such as cell temperatures and voltages of the batteries <NUM> from the batteries <NUM>.

As shown in <FIG>, a cover member <NUM> that covers upper part, rear part, and side part of the shelf <NUM> is installed to the machine-body frame <NUM>. The cover member <NUM>, which can be formed of an appropriate metal material, may be provided with a door and the like and may be configured to be accessible to the batteries <NUM> and the like accommodated in the shelf <NUM> by opening the door during maintenance.

In the electric-drive hydraulic excavator <NUM> configured as described above, since the supporting plates <NUM>, to which the batteries <NUM> are fixed, are installed on respective shelf plates <NUM> of the shelf <NUM> via the elastic mounts <NUM>, the effect of distortions of the shelf plates <NUM> on the supporting plates <NUM> is reduced by the elastic mounts <NUM> located between the shelf plates <NUM> and the supporting plates <NUM>, even if the shelf plates <NUM> are distorted by welding. Further, since welding is not performed on the supporting plates <NUM> that support the batteries <NUM>, distortion due to welding is not caused in the supporting plates <NUM>. Therefore, in the electric-drive hydraulic excavator <NUM>, damages of the batteries <NUM> can be prevented by suppressing generation of local high stresses on the batteries <NUM>.

Further, in the electric-drive hydraulic excavator <NUM>, since vibrations generated during traveling or the like are diminished by the elastic mounts <NUM>, malfunctions or internal damages of the batteries <NUM> due to exceeding allowable vibration of the batteries <NUM> can be prevented.

When assembling the electric-drive hydraulic excavator <NUM>, a plurality of batteries <NUM> can be easily installed on the machine-body frame <NUM>, by preparing in advance a battery shelf assembly (see <FIG>) in which the batteries <NUM> are attached to the shelf <NUM>, and fixing the battery shelf assembly to the rear end portion of the machine-body frame <NUM>, as shown in <FIG>.

The above-mentioned shelf <NUM> is fixed to the rear end portion of the machine-body frame <NUM> by bolts <NUM>, but as shown in <FIG>, the shelf <NUM> may be installed on the rear end portion of the machine-body frame <NUM> via additional elastic mounts <NUM>. In the example shown in <FIG>, a retainer plate <NUM> for retaining the plurality of additional elastic mounts <NUM> is fixed to the rear end portion of the machine-body frame <NUM> by bolts <NUM>, and the lowermost shelf plate <NUM> of the shelf <NUM> is fixed to the additional elastic mounts <NUM> by bolts <NUM>, and thereby the shelf <NUM> is installed on the rear end portion of the machine-body frame <NUM> via the additional elastic mounts <NUM>. In the example shown in <FIG>, vibrations transmitted to the batteries <NUM> are further reduced by the additional elastic mounts <NUM>. As the additional elastic mounts <NUM>, a liquid-filled viscous mount, for example, can be used.

In the illustrated embodiment, a description has been given of an example in which the supporting plates <NUM> are installed on the topsides of the shelf plates <NUM> via the elastic mounts <NUM>, and the shelf <NUM> and the elastic mounts <NUM> are interposed between the machine-body frame <NUM> and the supporting plates <NUM>. However, in the present invention, only the elastic mounts <NUM> may be configured to be interposed between the machine-body frame <NUM> and the supporting plates <NUM>.

Alternatively, as shown in <FIG>, one or more base plates <NUM> may be fixed to the rear end portion of the machine-body frame <NUM> by bolts <NUM>, and the supporting plates <NUM> may be installed on the topsides of the base plates <NUM> via the elastic mounts <NUM>. That is, the base plates <NUM> and the elastic mounts <NUM> may be interposed between the machine-body frame <NUM> and the supporting plates <NUM>. Not only drilling and tapping but also welding may be performed on the base plates <NUM>. The shelf <NUM>, in which the plurality of batteries <NUM> is installed, may be arranged above the base plates <NUM>.

Further, also in an example shown in <FIG>, damages of the batteries <NUM> are prevented by suppressing generation of local high stresses in the batteries <NUM>, and malfunctions or internal damages of the batteries <NUM> due to exceeding the allowable vibration of the batteries <NUM> can be prevented. Further, the plurality of batteries <NUM> can be easily installed on the machine-body frame <NUM>, by preparing in advance a battery base plate assembly in which the plurality of batteries <NUM> is attached to the base plate <NUM>, and fixing the battery base plate assembly to the rear end portion of the machine-body frame <NUM>.

Claim 1:
A construction machine comprising a machine-body frame (<NUM>), a supporting plate (<NUM>) installed on the machine-body frame (<NUM>), and batteries (<NUM>) fixed to a topside of the supporting plate (<NUM>), wherein a shelf (<NUM>) having a plurality of shelf plates (<NUM>) arranged at intervals in an up-down direction is installed on a rear end portion of the machine-body frame (<NUM>),
characterized in that
a plurality of supporting plates (<NUM>) is provided and installed on respective topsides of the plurality of shelf plates (<NUM>) via elastic mounts (<NUM>), wherein each of the supporting plates (<NUM>) is free of welds.