JP2024049237A - Electric Construction Machinery - Google Patents

Abstract

[Problem] To provide an electric construction machine capable of reducing the transmission of noise from an electric fan to a driver's cab and protecting the electric fan. [Solution] A revolving body 2 of an electric shovel includes a driver's cab 11 arranged at the front of a revolving frame 10, a counterweight 12 arranged at the rear of the revolving frame 10, a battery 13 arranged between the driver's cab 11 and the counterweight 12 on the revolving frame 10, electric fans 26a, 26b driven by the power of the battery 13, a heat exchanger 27a that cools hydraulic oil with cooling air generated by the electric fan 26a, and a heat exchanger 27b that cools cooling water with cooling air generated by the electric fan 26b. The electric fans 26a, 26b are arranged so that the battery 13 is interposed between them and the driver's cab 11, and the left and right sides are covered by the counterweight 12, for example. [Selected Figure] Figure 3

Description

The present invention relates to an electric construction machine.

Engine-driven construction machinery includes an engine, a hydraulic pump driven by the engine, a hydraulic actuator driven by hydraulic oil pressurized by the hydraulic pump, a fan connected to the output shaft of the engine, and a heat exchanger that cools the hydraulic oil or cooling water with cooling air generated by the fan. On the other hand, electric construction machinery includes an electric motor instead of an engine, and an electric fan instead of the fan connected to the output shaft of the engine. Compared to a fan connected to the output shaft of the engine, an electric fan has greater freedom in layout and is easier to control the speed.

Patent Document 1 discloses an electric shovel, which is one type of electric construction machine. This electric shovel comprises a running body, a rotating body rotatably provided above the running body, and a working device connected to the front side of the rotating body. The rotating body comprises a rotating frame, a cab-type driver's cab located at the front of the rotating frame, a battery located at the rear of the rotating frame, a main storage room formed between the driver's cab and the battery on the rotating frame, an electric motor, a hydraulic pump, a hydraulic oil tank, and a heat exchanger located in the main storage room, an opening/closing cover that opens and closes the opening of the main storage room, and an electric fan attached to the opening/closing cover.

JP 2021-063339 A

Electric construction machinery is not equipped with an engine, so the noise of the electric fan is easily noticeable. If the noise of the electric fan propagates through the structure that constitutes the electric construction machinery and reaches the driver's cab, it will disturb the driver inside the cab. In order to increase the degree of sound attenuation, it is preferable that the structure interposed between the electric fan and the driver's cab has a structure that is less likely to generate vibration, i.e., is a heavy object. In the electric excavator of Patent Document 1, a hydraulic oil tank or the like is interposed between the electric fan and the driver's cab. However, it cannot be said that the hydraulic oil tank has a structure that is less likely to generate vibration, or is a heavy object. Therefore, there is room for improvement in terms of reducing the transmission of the noise of the electric fan to the driver's cab.

In addition, in the electric excavator of Patent Document 1, the electric fan is covered with an openable cover. Therefore, there is room for improvement in terms of protecting the electric fan, considering the case where an object flies in and hits the fan, or the case where the rotation of the rotating body causes a collision with a surrounding object.

The present invention was made in consideration of the above, and its purpose is to provide an electric construction machine that can reduce the noise of the electric fan from being transmitted to the driver's cab and protect the electric fan.

In order to achieve the above object, the present invention provides an electric construction machine comprising a running body, a rotating body rotatably provided above the running body, and a work device connected to the front side of the rotating body, the rotating body comprising a rotating frame, a cab arranged at the front of the rotating frame, a counterweight arranged at the rear of the rotating frame, a battery arranged on the rotating frame between the cab and the counterweight, an electric motor driven by the power of the battery, a hydraulic pump driven by the electric motor and pressurizing hydraulic oil, an electric fan driven by the power of the battery, and a heat exchanger that cools the hydraulic oil or the cooling water with the cooling air generated by the electric fan, the electric fan is arranged so that the battery is interposed between the electric fan and the cab, and at least one of the upper side, lower side, left side, and right side is covered by the counterweight.

This invention reduces the noise of the electric fan from being transmitted to the driver's cab and protects the electric fan.

1 is a perspective view showing an overall structure of an electric shovel in one embodiment of the present invention. FIG. 2 is a top view showing the arrangement of equipment in a rotating body of the electric shovel in one embodiment of the present invention. FIG. 2 is a side view showing the arrangement of equipment in a rotating body of the electric shovel in one embodiment of the present invention. FIG. 2 is a rear view showing the arrangement of equipment in a rotating body of the electric shovel in one embodiment of the present invention. 1 is a diagram showing a configuration of a drive device of an electric shovel in one embodiment of the present invention. FIG.

One embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a perspective view showing the overall structure of an electric shovel in this embodiment. Figures 2 to 4 are a top view, a side view, and a rear view showing the arrangement of equipment on the rotating body of the electric shovel in this embodiment. Note that for convenience, some equipment has been omitted from Figure 2.

The electric excavator of this embodiment includes a running body 1, a rotating body 2 rotatably provided on the upper side of the running body 1, and a working device 3 connected to the front side of the rotating body 2. The running body 1 runs by the rotation of a running motor (not shown), and the rotating body 2 rotates by the rotation of a rotation motor (not shown).

The working device 3 includes a boom 4 connected to the front of the rotating body 2 so as to be rotatable in the vertical direction, an arm 5 connected to the tip of the boom 4 so as to be rotatable in the vertical direction, and a bucket 6 (working tool) connected to the tip of the arm 5 so as to be rotatable in the vertical direction. The boom 4 rotates by the extension and retraction of a boom cylinder 7, the arm rotates by the extension and retraction of an arm cylinder 8, and the bucket 6 rotates by the extension and retraction of a bucket cylinder 9 (working tool cylinder). The bucket 6 is replaceable with another working tool.

The rotating body 2 comprises a rotating frame 10 forming the lower foundation structure, a cab-type operator's cab 11 located at the front of the rotating frame 10, a counterweight 12 located at the rear of the rotating frame 10, and a battery (e.g., a lithium-ion battery) 13 located between the operator's cab 11 and the counterweight 12 on the rotating frame 10. A number of operating devices (not shown) that can be operated by the operator are provided within the operator's cab 11.

The electric shovel is equipped with a drive unit that drives multiple hydraulic actuators (more specifically, the travel motor, swing motor, boom cylinder 7, arm cylinder 8, and bucket cylinder 9) in response to the operation of multiple operating devices. Figure 5 shows the configuration related to the boom cylinder 7 of the configuration of the drive unit of the electric shovel in this embodiment.

The drive device of this embodiment includes an inverter 14 that converts DC power from the battery 13 into AC power, an electric motor 15 that is driven by the power converted by the inverter 14, a hydraulic pump 16 and a pilot pump 17 that are driven by the electric motor 15, a control valve 18 that controls the flow of pressurized oil (more specifically, the direction and flow rate) from the hydraulic pump 16 to the boom cylinder 7, and an operating device 19 that switches the control valve 18. As described above, the operating device 19 is mounted in the cab 11 of the rotating body 2, and the inverter 14, the electric motor 15, the hydraulic pump 16, the pilot pump 17, and the control valve 18 are mounted in other parts of the rotating body 2.

The operating device 19 has an operating lever 20 that can be operated by the driver, a pilot valve 21a that reduces the discharge pressure of the pilot pump 17 to generate pilot pressure depending on the amount of operation of one side of the operating lever 20, and a pilot valve 21b that reduces the discharge pressure of the pilot pump 17 to generate pilot pressure depending on the amount of operation of the other side of the operating lever 20.

When the operator operates the control lever 20 to one side, pilot pressure generated by the pilot valve 21a according to the amount of operation is output to the pressure receiving portion 22a of the control valve 18. This switches the control valve 18 to the switching position on the right side in the figure, and pressure oil pressurized by the hydraulic pump 16 is supplied to the rod side of the boom cylinder 7 via the control valve 18, causing the boom cylinder 7 to retract. As a result, the boom 4 is lowered.

When the operator operates the operating lever 20 to the opposite side, pilot pressure generated by the pilot valve 21b according to the amount of operation is output to the pressure receiving portion 22b of the control valve 18. This switches the control valve 18 to the switching position on the left side in the figure, and pressure oil pressurized by the hydraulic pump 16 is supplied to the bottom side of the boom cylinder 7 via the control valve 18, causing the boom cylinder 7 to extend. As a result, the boom 4 rises.

Returning to Figures 2 to 4 above, the counterweight 12 is made up of counterweight segments 23a and 23b that are split in the left-right direction, and has an overall arch-like shape when viewed from above (in other words, a shape consisting of a circular arc and line segments connecting both ends of the arc). The counterweight segments 23a and 23b are made, for example, by filling a steel container with heavy concrete or the like. A storage chamber 24 is formed between the counterweight segments 23a and 23b, and a cover (not shown) is attached to cover the upper and rear sides of the storage chamber 24.

As a feature of this embodiment, the storage chamber 24 of the counterweight 12 houses heat exchanger units 25a and 25b. The heat exchanger unit 25a is composed of an electric fan 26a driven by the power of the battery 13, and a heat exchanger (oil cooler) 27a that cools the hydraulic oil with the cooling air generated by the electric fan 26a. The heat exchanger unit 25b is composed of an electric fan 26b driven by the power of the battery 13, and a heat exchanger (radiator) 27b that cools the cooling water with the cooling air generated by the electric fan 26b.

In the present embodiment configured as described above, the electric fans 26a, 26b are arranged with the battery 13 between them and the cab 11, and the left and right sides (in other words, both sides in the width direction of the rotating body 2) are covered by the counterweight segments 23a, 23b (see Figures 2 to 4). The battery 13 is a heavy object, that is, it is less likely to generate vibrations compared to, for example, a hydraulic oil tank. Therefore, the noise of the electric fans 26a, 26b can be reduced from being transmitted to the cab 11. In addition, the left and right sides of the electric fans 26a, 26b are covered by the counterweight segments 23a, 23b. Therefore, the electric fans 26a, 26b can be protected even if an object flies in and collides with them, or if the rotating body 2 collides with surrounding objects due to its rotation.

In the above embodiment, the counterweight 12 is divided into counterweight segments 23a and 23b, and the left and right sides of the electric fans 26a and 26b are covered by the counterweight segments 23a and 23b. However, this is not limiting. The counterweight 12 does not have to be divided, and at least one of the upper, lower, left, and right sides of the electric fans 26a and 26b needs to be covered by the counterweight 12. This allows the electric fans 26a and 26b to be protected, although the degree of protection varies.

In the above, an electric shovel has been used as an example of an application of the present invention, but the present invention is not limited to this. In other words, the present invention may be applied to electric construction machines other than electric shovels.

REFERENCE SIGNS LIST 1 Traveling body 2 Swinging body 3 Working device 10 Swing frame 11 Cab 12 Counterweight 13 Battery 15 Electric motor 16 Hydraulic pump 26a, 26b Electric fan 27a, 27b Heat exchanger

Claims (3)

The vehicle includes a traveling body, a rotating body rotatably provided on an upper side of the traveling body, and a working device connected to a front side of the rotating body,
In an electric construction machine, the rotating body includes a rotating frame, a cab arranged in front of the rotating frame, a counterweight arranged in the rear of the rotating frame, a battery arranged on the rotating frame between the cab and the counterweight, an electric motor driven by power from the battery, a hydraulic pump driven by the electric motor and pressurizing hydraulic oil, an electric fan driven by power from the battery, and a heat exchanger that cools the hydraulic oil or cooling water with cooling air generated by the electric fan,
1. An electric construction machine comprising: a driver's cab and an electric fan; a counterweight that covers at least one of an upper side, a lower side, a left side, and a right side of the electric fan; and a counterweight that covers at least one of the upper side, the lower side, the left side, and the right side of the electric fan. The electric construction machine according to claim 1,
The electric construction machine is characterized in that the electric fan is covered on both the left and right sides by the counterweight. The electric construction machine according to claim 2,
The electric construction machine is characterized in that the counterweight has an overall shape of a bow when viewed from above.

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