Electric construction machine

Abstract

Provided is an electric construction machine capable of suppressing damage to a power feed cable. An electric excavator includes a rotation angle sensor that detects a rotation angle of a rotating body, a cable support frame that is disposed on the rotating body and has a grip portion that grips a power supply cable, a rotation angle sensor that detects a rotation angle of the grip portion of the cable support frame, a rotation lock valve, and a controller. When the connection sensor detects that the power supply cable is connected to the power supply port, the controller calculates the position of the holding part of the cable support frame based on the rotation angle sensor and the detection result of the rotation angle sensor. Furthermore, when the calculated position of the grip part is out of the predetermined range, the rotation lock valve is controlled to be in an off state, and the rotation of the rotating body is prohibited.

Description

Technical Field

[0001] The invention relates to an electric engineering machine capable of being connected with a feeder cable. Background Art

[0002] An electric excavator, which is one of the electric construction machines, has, for example: a traveling body; a rotating body rotatably arranged on the upper side of the traveling body; a working device connected to the front side of the rotating body; an electric motor mounted on the rotating body; a hydraulic pump mounted on the rotating body and driven by the electric motor; and a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump. Some electric excavators are configured to connect a feeder cable to the rotating body side, and supply power from an external power source via the feeder cable. And the electric motor is driven by the power supplied via the feeder cable. Alternatively, the battery mounted on the rotating body is charged by the power supplied via the feeder cable, and the electric motor is driven by the power of the battery.

[0003] The electric excavator of Patent Document 1 is configured such that the excavator does not perform operations (specifically, rotation operations and travel operations) when the power supply cable is connected, thereby preventing the power supply cable from being damaged.

[0004] The electric excavator of Patent Document 2 is configured to be able to perform excavation operations when a feeder cable is connected, and has a cable support frame for suppressing damage to the feeder cable. The cable support frame is arranged on the rear side of the rotating body (in other words, the opposite side of the working device), has a gripping portion for gripping the feeder cable, and is configured in a manner that the gripping portion can be rotated around a vertical axis. In addition, for example, according to the rotation of the rotating body, the gripping portion of the cable support frame is rotated in the opposite direction thereof, thereby preventing an excessive load from being applied to the feeder cable.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 4504940

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-084099 Summary of the invention

[0009] If the cable support frame of Patent Document 2 is used, even when the feeder cable is connected, damage to the feeder cable can be suppressed while the excavator is in motion. However, the position of the gripping portion of the cable support frame will change significantly depending on the rotation angle of the rotating body, and there is a possibility that the feeder cable gripped by the gripping portion of the cable support frame will come into contact with the traveling body and be damaged. In addition, depending on the position of the gripping portion of the cable support frame and the traveling direction of the traveling body, there is a possibility that the feeder cable gripped by the gripping portion of the cable support frame will be crushed and damaged by the traveling body.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric construction machine capable of suppressing damage to a power feeder cable.

[0011] In order to achieve the above-mentioned purpose, the representative present invention comprises: a traveling body; a rotating body rotatably arranged on the upper side of the traveling body; a working device connected to the rotating body; a feeding port arranged on the rotating body and connected to a feeding cable from an external power source; a cable support frame arranged on the rotating body and having a gripping portion for gripping the feeding cable, the cable support frame being constructed in a manner that enables the gripping portion to rotate around a vertical axis, wherein the electric construction machinery comprises: a connection sensor that detects a state in which the feeding cable is connected to the feeding port; a rotation angle sensor that detects a rotation angle of the rotating body ; a rotation angle sensor that detects the rotation angle of the grip of the cable support; a rotation locking device that is set to a locked state that prohibits the rotation of the rotating body; and a controller that controls the rotation locking device, wherein the controller calculates the position of the grip of the cable support based on the rotation angle sensor and the detection results of the rotation angle sensor when the connection sensor detects that the feeding cable is connected to the feeding port, and controls the rotation locking device to a locked state when the calculated position of the grip of the cable support is out of a specified range.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to suppress damage to the power feeder cable caused by the operation of the electric construction machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view showing the structure of the electric excavator in the first embodiment of the present invention.

[0015] Figure 2 It is a plan view showing the structure of a rotating body of the electric excavator in the first embodiment of the present invention.

[0016] Figure 3It is a diagram showing a configuration related to a swing motor among the configurations of a drive device for an electric excavator according to a first embodiment of the present invention.

[0017] Figure 4 It is a diagram showing the configuration of an electrical system of an electric excavator in the first embodiment of the present invention.

[0018] Figure 5 This is a flowchart showing the contents of the rotation lock control in the first embodiment of the present invention.

[0019] Fig. 6A It is a plan view showing a specific example of the operation of the electric excavator in the first embodiment of the present invention and showing a predetermined range set with respect to the position of the grip portion of the cable support.

[0020] Figure 6B It is a plan view showing a specific example of the operation of the electric excavator in the first embodiment of the present invention and showing a predetermined range set with respect to the position of the grip portion of the cable support.

[0021] Figure 7 It is a diagram showing the configuration of an electrical system of an electric excavator in a first modified example of the present invention.

[0022] Figure 8 It is a plan view showing a predetermined range set with respect to the position of the gripping portion of the cable support in the first modified example of the present invention.

[0023] Fig. 9A It is a plan view showing a specific example of the operation of the electric excavator in the first modified example of the present invention.

[0024] Fig. 9B It is a plan view showing a specific example of the operation of the electric excavator in the first modified example of the present invention.

[0025] Fig.10 It is a diagram showing a configuration related to a travel motor among the configurations of a drive device for an electric excavator according to a second embodiment of the present invention.

[0026] Fig.11 It is a diagram showing the configuration of an electrical system of an electric excavator in a second embodiment of the present invention.

[0027] Fig.12 This is a flowchart showing the content of the travel lock control in the second embodiment of the present invention.

[0028] Fig.13A It is a plan view showing a specific example of the operation of the electric excavator in the second embodiment of the present invention and showing a first range and a second range set with respect to the position of the grip portion of the cable support.

[0029] Fig. 13B It is a plan view showing a specific example of the operation of the electric excavator in the second embodiment of the present invention.

[0030] Fig.14 It is a diagram showing the configuration of an electrical system of an electric excavator in a second modified example of the present invention.

[0031] Fig.15 It is a plan view showing a first range and a second range set with respect to the position of the gripping portion of the cable support in a second modified example of the present invention.

[0032] Fig.16A It is a plan view showing a specific example of the operation of the electric excavator in the second modified example of the present invention.

[0033] Fig. 16B It is a plan view showing a specific example of the operation of the electric excavator in the second modified example of the present invention. DETAILED DESCRIPTION

[0034] A first embodiment of the present invention will be described with reference to the drawings.

[0035] Figure 1 It is a side view showing the structure of the electric excavator in this embodiment. Figure 2 1 is a plan view showing the structure of the rotating body of the electric excavator in this embodiment. Figure 2 In FIG. 1 , in order to show the equipment mounted on the rotating body, a state in which a part of the outer cover of the rotating body is removed is shown.

[0036] The electric excavator of this embodiment includes a traveling body 11, a rotating body 12 rotatably provided on the upper side of the traveling body 11, and a front side ( Figure 1 The rotating body 12 is rotated by the rotation of the rotating motor 14, and its rotation angle is detected by the rotation angle sensor 15 (see below). Figure 4 ) detection.

[0037] The traveling body 11 has: a crawler frame 16 that is, for example, H-shaped when viewed from above; Figure 1 The invention also includes a driving wheel 17 at the rear end (the paper surface is the near front side); a driven wheel 18 arranged at the front end of the left side of the track frame 16; a crawler track 19 wound around the left driving wheel 17 and the left side of the driven wheel 18; and a travel motor 20A on the left side that drives the left driving wheel 17 (and thus, the left crawler track 19).

[0038] In addition, the traveling body 11 has: a right side (relative to the right side) of the crawler frame 16; Figure 1The invention also includes a driving wheel (not shown) at the rear end of the track frame 16 (with the paper surface as the inner side); a driven wheel (not shown) arranged at the front end of the right side of the track frame 16; a crawler track on the right side wound around the right driving wheel and the driven wheel; and a right travel motor 20B (see the figure described later) that drives the right driving wheel (and thus, the right crawler track).

[0039] The working device 13 includes, for example, a swing column 21 rotatably connected to the front side of the swing body 12 in the left-right direction, a boom 22 rotatably connected to the upper side of the swing column 21 in the up-down direction, an arm 23 rotatably connected to the front end side of the arm 22 in the up-down direction, and a bucket 24 rotatably connected to the front end side of the arm 23 in the up-down direction. The swing column 21 rotates by extension and contraction of a swing hydraulic cylinder (not shown), the boom 22 rotates by extension and contraction of an arm hydraulic cylinder 25, the arm 23 rotates by extension and contraction of an arm hydraulic cylinder 26, and the bucket 24 rotates by extension and contraction of a bucket hydraulic cylinder 27.

[0040] The rotating body 12 has: a rotating frame 28 constituting a lower basic structure; a rotating frame 28 provided on the left side (relative to the left side) of the rotating frame 28; Figure 1 The paper side is near the front side, Figure 2 and provided on the rear side of the rotating frame 28 ( Figure 1 as well as Figure 2 The counterweight 30 is on the right side of the device.

[0041] In addition, the rotating body 12 has: a feeding port 31 arranged on the upper side of the counterweight 30 and for connecting a feeding cable 2 from an external power source 1 (e.g., a commercial power supply); a connection sensor 32 for detecting a state in which the feeding cable 2 is connected to the feeding port 31; and a cable support frame 33 provided on the upper side of the counterweight 30 and for guiding the feeding cable 2.

[0042] The cable support frame 33 includes: a rotating shaft 34 supported in a manner rotatable around a vertical axis; a support frame 35 extending in the horizontal direction from the rotating shaft 34; a gripping portion 36 (clamp) provided on the front end side of the support frame 35 and gripping the feed cable 2; and a rotation angle sensor 37 (see below) for detecting the rotation angle of the rotating shaft 34, that is, the rotation angle of the gripping portion 36. Figure 4 ).

[0043] For example, when the rotating body 12 rotates in a clockwise direction as viewed from above relative to the traveling body 11, the gripping portion 36 of the cable support frame 33 rotates in a counterclockwise direction as viewed from above relative to the rotating body 12. In addition, for example, when the rotating body 12 rotates in a counterclockwise direction as viewed from above relative to the traveling body 11, the gripping portion of the cable support frame 33 rotates in a clockwise direction as viewed from above relative to the rotating body 12. As a result, an excessive load is not applied to the feed cable 2. However, for reasons such as avoiding contact between the gripping portion 36 of the cable support frame 33 and the cabin 29, etc., the rotation range of the rotating shaft 34, that is, the rotation range of the gripping portion 36 is limited by a stopper not shown.

[0044] In this embodiment, the grip portion 36 is directed toward the rear of the rotating body 12 (see Figure 1 as well as Figure 2 ) is defined as the reference value (0 degree) of the rotation angle of the grip portion 36 of the cable support frame 33. And, when it is defined that the rotation angle of the grip portion 36 increases as the grip portion 36 rotates clockwise from the above state, the rotation angle of the grip portion 36 is limited to 90 degrees, for example. In addition, when it is defined that the rotation angle of the grip portion 36 increases as the grip portion 36 rotates counterclockwise from the above state, the rotation angle of the grip portion 36 is limited to 90 degrees, for example.

[0045] A driver's seat (not shown) is provided in the cabin 29. A driving operation lever and pedals 38A and 38B (see the following) that can be operated by the driver are provided in front of the driver's seat. Fig.10 The travel operating levers and pedals 38A and 38B indicate the movement of the travel body 11 by operating in the front-rear direction. A swing operating pedal (not shown) operable by the driver is provided on the right side of the travel operating levers and pedals 38A and 38B. The swing operating pedal indicates the movement of the swing column 21 by operating in the left-right direction.

[0046] On the left side of the driver's seat, there is provided an operating lever 39 (see the following description) which can be operated by the driver. Figure 3 The operation lever 39 indicates the movement of the rotating body 12 by operating in the left-right direction, and indicates the movement of the boom 23 by operating in the front-back direction. A work operation lever (not shown) that can be operated by the operator is provided on the right side of the driver's seat. The work operation lever indicates the movement of the bucket 24 by operating in the left-right direction, and indicates the movement of the boom 22 by operating in the front-back direction.

[0047] The electric excavator has a drive device that drives a plurality of hydraulic actuators (specifically, the aforementioned swing motor 14 , travel motors 20A, 20B, swing cylinder, boom cylinder 25 , arm cylinder 26 , and bucket cylinder 27 ). Figure 3 It is a diagram showing a configuration related to a swing motor among the configurations of a drive device of an electric excavator in the present embodiment.

[0048] The drive device of this embodiment includes: an electric motor 40; a hydraulic pump 41 and a pilot pump 42 driven by the electric motor 40; a rotation control valve 43 that controls the flow (specifically, direction and flow rate) of hydraulic oil from the hydraulic pump 41 to the rotation motor 14; and a work operation device 44 that switches the rotation control valve 43. In addition, the work operation device 44 is mounted in the cabin 29 of the rotating body 12, and the electric motor 40, the hydraulic pump 41, the pilot pump 42, and the rotation control valve 43 are mounted in other parts of the rotating body 12 (refer to the above Figure 2 ).

[0049] The operating device 44 for operation includes: the above-mentioned operating lever 39 for operation; a first pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the left operation amount of the operating lever 39 for operation; and a second pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the right operation amount of the operating lever 39 for operation.

[0050] When the driver operates the operation lever 39 to the left, the pilot pressure generated by the first pilot valve according to the operation amount is output to the pressure receiving part on one side of the rotation control valve 43. As a result, the rotation control valve 43 is switched to the switching position on the left side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the left side of the figure of the rotation motor 14 through the rotation control valve 43, and the rotation motor 14 rotates in one direction. As a result, the rotating body 12 rotates in the left direction (in other words, the counterclockwise direction when viewed from above).

[0051] When the driver operates the operation lever 39 to the right, the pilot pressure generated by the second pilot valve according to the operation amount is output to the pressure receiving part on the other side of the rotation control valve 43. As a result, the rotation control valve 43 is switched to the switching position on the right side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the right side of the figure of the rotation motor 14 through the rotation control valve 43, and the rotation motor 14 rotates in the opposite direction. As a result, the rotating body 12 rotates in the right direction (in other words, the clockwise direction when viewed from above).

[0052] As one of the features of this embodiment, a rotation lock valve 45A that can be switched between a shutoff state and a connected state is provided in the oil passage between the first pilot valve of the operating device 44 and the pressure receiving portion on one side of the rotation control valve 43, and a rotation lock valve 45B that can be switched between a shutoff state and a connected state is provided in the oil passage between the second pilot valve of the operating device 44 and the pressure receiving portion on the other side of the rotation control valve 43. The rotation lock valves 45A and 45B correspond to the rotation lock devices that are set to a locked state to prohibit the rotation of the rotating body as described in the technical solution.

[0053] When the rotation lock valves 45A and 45B are in the blocked state (locked state), the rotation control valve 43 is not switched regardless of the left-right operation of the work operating lever 39, so the rotation motor 14 does not rotate. In other words, the rotation of the rotating body 12 is prohibited. On the other hand, when the rotation lock valves 45A and 45B are in the connected state (unlocked state), the rotation control valve 43 is switched according to the left-right operation of the work operating lever 39, so the rotation motor 14 rotates. In other words, the rotation of the rotating body 12 is allowed.

[0054] The electric motor 40 is driven by electric power supplied from the external power source 1 via the power supply cable 2. Alternatively, the electric motor 40 is driven by a battery 46 (see the following description) charged by electric power supplied from the external power source 1 via the power supply cable 2. Figure 4 ) is used to drive the Figure 4 The electrical system of the electric excavator configured in this manner will be described. Figure 4 This is a block diagram showing the configuration of the electrical system of the electric excavator in the present embodiment together with related devices.

[0055] The electrical system of this embodiment includes: a rectifier 47 that converts AC power supplied from an external power source 1 via a feed cable 2 into DC power; an inverter 48 that controls the rotation speed of the electric motor 40; a converter 49 that switches the connection between the rectifier 47, the inverter 48, and the battery 46; and a controller 50 that controls the converter 49 and the inverter 48. In addition, the battery 46, the rectifier 47, the inverter 48, the converter 49, and the controller 50 are mounted on the rotating body 12 (see the above Figure 2 ).

[0056] Although not shown, the controller 50 includes a processor that executes processing according to a program, a memory that stores programs and data, etc. When the connection sensor 32 detects that the feed cable 2 is connected to the feed port 31, the controller 50 controls the converter 49 to connect the rectifier 47 and the inverter 48. In this case, the electric motor 40 is driven by the power supplied from the external power supply 1 via the feed cable 2.

[0057] Alternatively, when the connection sensor 32 detects that the feed cable 2 is connected to the feed port 31, the controller 50 controls the converter 49 to connect the rectifier 47 to the battery 46. Thus, the battery 46 is charged by the power supplied from the external power supply 1 via the feed cable 2. When the connection sensor 32 detects that the feed cable 2 is not connected to the feed port 31, the controller 50 controls the converter 49 to connect the inverter 48 to the battery 46. In this case, the electric motor 40 is driven by the power of the battery 46.

[0058] As one of the features of this embodiment, when the connection sensor 32 detects that the feed cable 2 is connected to the feed port 31, the controller 50 calculates the position of the grip 36 of the cable support frame 33 (for example, polar coordinates with the center of the traveling body 11 as the origin) based on the detection results of the rotation angle sensor 15 and the rotation angle sensor 37. Then, the controller 50 performs rotation locking control of the rotation locking valves 45A and 45B based on the calculated position of the grip 36 of the cable support frame 33.

[0059] use Figure 5 The above-mentioned rotation lock control will be described. Figure 5 : is a flowchart showing the content of the rotation lock control in this embodiment.

[0060] In step S1, the controller 50 determines whether the feed cable 2 is connected to the feed port 31 based on the detection result of the connection sensor 32. If the feed cable 2 is not connected to the feed port 31, the process proceeds to step S2. In step S2, the controller 50 controls the rotation lock valves 45A and 45B to be unlocked. Thus, the rotation of the rotating body 12 is allowed.

[0061] When the power cable 2 is connected to the power feed port 31, the process proceeds to step S3. In step S3, the controller 50 calculates the position of the gripping portion 36 of the cable support frame 33 based on the detection results of the rotation angle sensor 15 and the rotation angle sensor 37. Then, the process proceeds to step S4 to determine whether the calculated position of the gripping portion 36 of the cable support frame 33 is within the specified range D1. Fig. 6A as well as Figure 6B As shown, the predetermined range D1 is preset as a range where the power supply cable 2 held by the holding portion 36 of the cable support frame 33 does not contact the traveling body 11 assuming that the external power source 1 is disposed on the rear side of the traveling body 11 , and is stored in the controller 50 .

[0062] For example Fig. 6AAs shown, when the calculated position of the gripping portion 36 of the cable support frame 33 is within the predetermined range D1, the process proceeds to step S2. In step S2, the controller 50 controls the rotation lock valves 45A and 45B to be unlocked. Thus, the rotation of the rotating body 12 is allowed. On the other hand, for example Figure 6B As shown, when the calculated position of the gripping portion 36 of the cable support 33 is out of the predetermined range D1, the process proceeds to step S5. In step S5, the controller 50 controls the rotation lock valves 45A and 45B to lock the state. Thus, the rotation of the rotating body 12 is prohibited.

[0063] As described above, the electric excavator of this embodiment can perform a rotational motion even when the feeder cable 2 is connected. However, in the case where there is a possibility that the feeder cable 2 held by the holding portion 36 of the cable support frame 33 contacts the traveling body 11 and is damaged, the rotational motion is prohibited. Thus, damage to the feeder cable 2 can be suppressed.

[0064] In addition, in the first embodiment, the case where the predetermined range set relative to the position of the grip portion 36 of the cable support frame 33 is fixed is described as an example based on the premise that the external power source 1 is arranged at the rear side of the traveling body 11, but the present invention is not limited to this. In other words, the predetermined range set relative to the grip portion 36 of the cable support frame 33 may be changed according to the arrangement of the external power source 1. Figure 7 , Figure 8 , Fig. 9A ,as well as Fig. 9B The same reference numerals are given to the same parts as those in the first embodiment, and the description thereof will be omitted as appropriate.

[0065] The electric excavator of this modified example has an input device 51 (see FIG. 1 ) which is arranged in the cabin 29 and can input the position of the external power source 1 with respect to the traveling body 11. Figure 7 The input device 51 includes, for example, a display for displaying that any one of the rear side, left side, and right side of the traveling body 11 is selected as the configuration of the external power source 1, and a button for selecting any one of the rear side, left side, and right side of the traveling body 11 as the configuration of the external power source 1.

[0066] The controller 50 stores the predetermined ranges D1, D2, and D3 (see Figure 8 The predetermined range D1 is as described above when the external power source 1 is arranged on the rear side of the traveling body 11 ( Figure 8 The predetermined range D2 is a range in which the power supply cable 2 held by the holding portion 36 of the cable support frame 33 does not contact the traveling body 11, based on the premise that the external power supply 1 is arranged on the left side of the traveling body 11 ( Figure 8The predetermined range D3 is a range where the power supply cable 2 held by the holding portion 36 of the cable support frame 33 does not contact the traveling body 11, provided that the external power supply 1 is disposed on the right side of the traveling body 11 ( Figure 8 The range in which the power feeding cable 2 held by the holding portion 36 of the cable support frame 33 does not come into contact with the traveling body 11 is pre-set as a premise.

[0067] The controller 50 changes the predetermined range according to the configuration of the external power source 1 inputted from the input device 51. For example Fig. 9A as well as Fig. 9B As shown in FIG. 1 , when the external power source 1 input by the input device 51 is disposed on the right side of the traveling body 11, the range is changed to the predetermined range D3. Fig. 9A as well as Fig. 9B As shown, when the position of the gripping portion 36 of the cable support 33 deviates from the predetermined range D1, the rotation lock valves 45A and 45B are controlled to be locked, and the rotation of the rotating body 12 is prohibited.

[0068] In this modification as well, the same effects as those of the first embodiment can be obtained.

[0069] A second embodiment of the present invention will be described with reference to the drawings. In this embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and the description thereof will be omitted as appropriate.

[0070] Fig.10 It is a diagram showing a configuration related to a travel motor among the configurations of a drive device of an electric excavator in the present embodiment. Fig.11 This is a block diagram showing the configuration of the electrical system of the electric excavator in the present embodiment together with related devices.

[0071] The drive device of this embodiment includes: a travel control valve 52A that controls the flow (specifically, direction and flow rate) of hydraulic oil from the hydraulic pump 41 to the travel motor 20A on the left side; a travel operating device 53A that switches the travel control valve 52A; a travel control valve 52B that controls the flow (specifically, direction and flow rate) of hydraulic oil from the hydraulic pump 41 to the travel motor 20B on the right side; and a travel operating device 53B that switches the travel control valve 52B. In addition, the travel operating devices 53A and 53B are mounted in the cabin 29 of the rotating body 12, and the travel control valves 52A and 52B are mounted in other parts of the rotating body 12.

[0072] The travel operating device 53A includes: the above-mentioned travel operating lever·pedal 38A; a third pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the front side operation amount of the travel operating lever·pedal 38A; and a fourth pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the rear side operation amount of the travel operating lever·pedal 38A.

[0073] The travel operating device 53B includes: the above-mentioned travel operating lever·pedal 38B; a 5th pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the front side operation amount of the travel operating lever·pedal 38B; and a 6th pilot valve (not shown) that reduces the discharge pressure of the pilot pump 42 and generates a pilot pressure according to the rear side operation amount of the travel operating lever·pedal 38B.

[0074] When the driver operates the travel operating lever and pedal 38A to the front side, the pilot pressure generated by the third pilot valve according to the operation amount is output to the pressure receiving part on one side of the travel control valve 52A. As a result, the travel control valve 52A is switched to the switching position on the left side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the left side of the figure of the travel motor 20A via the travel control valve 52A, and the travel motor 20A rotates forward. At the same time, when the driver operates the travel operating lever and pedal 38B to the front side, the pilot pressure generated by the fifth pilot valve according to the operation amount is output to the pressure receiving part on one side of the travel control valve 52B. As a result, the travel control valve 52B is switched to the switching position on the left side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the left side of the figure of the travel motor 20B via the travel control valve 52B, and the travel motor 20B rotates forward. As a result, the travel body 11 moves forward.

[0075] When the driver operates the travel operating lever and pedal 38A to the rear side, the pilot pressure generated by the fourth pilot valve according to the operation amount is output to the pressure receiving part on the other side of the travel control valve 52A. As a result, the travel control valve 52A is switched to the switching position on the right side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the right side of the figure of the travel motor 20A via the travel control valve 52A, and the travel motor 20A rotates backward. At the same time, when the driver operates the travel operating lever and pedal 38B to the rear side, the pilot pressure generated by the sixth pilot valve according to the operation amount is output to the pressure receiving part on the other side of the travel control valve 52B. As a result, the travel control valve 52B is switched to the switching position on the right side of the figure, and the hydraulic oil from the hydraulic pump 41 is supplied to the port on the right side of the figure of the travel motor 20B via the travel control valve 52B, and the travel motor 20B rotates backward. As a result, the travel body 11 moves backward.

[0076] As one of the features of this embodiment, a forward locking valve 54A that can be switched between a shutoff state and a connected state is provided in the oil passage between the third pilot valve of the travel operating device 53A and the pressure receiving portion on one side of the travel control valve 52A, and a forward locking valve 54B that can be switched between a shutoff state and a connected state is provided in the oil passage between the fifth pilot valve of the travel operating device 53B and the pressure receiving portion on one side of the travel control valve 52B. The forward locking valves 54A and 54B correspond to the forward locking devices that are set to a locked state to prohibit the forward movement of the travel body as described in the technical solution.

[0077] When the forward locking valves 54A and 54B are in the blocked state (locked state), the travel control valves 52A and 52B are not switched regardless of the front operation of the travel operating levers and pedals 38A and 38B, so the travel motors 20A and 20B do not rotate forward. In other words, the forward movement of the travel body 11 is prohibited. On the other hand, when the forward locking valves 54A and 54B are in the connected state (unlocked state), the travel control valves 52A and 52B are switched according to the front operation of the travel operating levers and pedals 38A and 38B, so the travel motors 20A and 20B rotate forward. In other words, the forward movement of the travel body 11 is permitted.

[0078] As one of the features of this embodiment, a reverse locking valve 55A that can be switched between a shutoff state and a connected state is provided in the oil passage between the fourth pilot valve of the travel operating device 53A and the pressure receiving portion on the other side of the travel control valve 52A, and a reverse locking valve 55B that can be switched between a shutoff state and a connected state is provided in the oil passage between the sixth pilot valve of the travel operating device 53B and the pressure receiving portion on the other side of the travel control valve 52B. The reverse locking valves 55A and 55B correspond to the reverse locking device that is set to a locked state to prohibit the travel body from moving backward as described in the technical solution.

[0079] When the reverse locking valves 55A and 55B are in the cut-off state (locked state), the travel control valves 52A and 52B are not switched regardless of the rear side operation of the travel operating levers and pedals 38A and 38B, so the travel motors 20A and 20B do not rotate backward. In other words, the travel body 11 is prohibited from moving backward. On the other hand, when the reverse locking valves 55A and 55B are in the connected state (unlocked state), the travel control valves 52A and 52B are switched according to the rear side operation of the travel operating levers and pedals 38A and 38B, so the travel motors 20A and 20B rotate backward. In other words, the travel body 11 is allowed to move backward.

[0080] As one of the features of this embodiment, when the connection sensor 32 detects that the feed cable 2 is connected to the feed port 31, the controller 50 calculates the position of the grip 36 of the cable support frame 33 (for example, polar coordinates with the center of the traveling body 11 as the origin) based on the detection results of the rotation angle sensor 15 and the rotation angle sensor 37. And, the forward locking valves 54A, 54B and the reverse locking valves 55A, 55B are controlled to travel lock according to the calculated position of the grip 36 of the cable support frame 33.

[0081] use Fig.12 The above-mentioned travel lock control will be described. Fig.12 : is a flowchart showing the content of the travel lock control in this embodiment.

[0082] In step S1, the controller 50 determines whether the feed cable 2 is connected to the feed port 31 based on the detection result of the connection sensor 32. If the feed cable 2 is not connected to the feed port 31, the process proceeds to step S6. In step S6, the controller 50 controls the forward locking valves 54A, 54B and the reverse locking valves 55A, 55B to be unlocked. Thus, the forward and reverse movement of the traveling body 11 is allowed.

[0083] When the power cable 2 is connected to the power feed port 31, the process proceeds to step S3. In step S3, the controller 50 calculates the position of the gripping portion 36 of the cable support frame 33 based on the detection results of the rotation angle sensor 15 and the rotation angle sensor 37. Then, the process proceeds to step S7 to determine whether the calculated position of the gripping portion 36 of the cable support frame 33 is within the first range E1. The first range E1 is, if Fig.13A As shown, the range is preset as a possibility that the power supply cable 2 held by the holding portion 36 of the cable support frame 33 may be crushed by the moving body 11 , assuming that the external power source 1 is disposed on the rear side of the traveling body 11 , and is stored in the controller 50 .

[0084] For example Fig.13A As shown, when the calculated position of the gripping portion 36 of the cable support frame 33 is not within the first range E1, the process proceeds to step S8. In step S8, the controller 50 controls the forward locking valves 54A and 54B to be unlocked. Thus, the forward movement of the traveling body 11 is permitted. On the other hand, for example Fig. 13B As shown, when the calculated position of the gripping portion 36 of the cable support 33 is within the first range E1, the process proceeds to step S9. In step S9, the controller 50 controls the forward locking valves 54A and 54B to be in the locked state. Thus, the forward movement of the traveling body 11 is prohibited.

[0085] Then, the process proceeds to step S10, where the controller 50 determines whether the calculated position of the gripping portion 36 of the cable support frame 33 is within the second range F1. Fig.13A As shown, the second range F1 is pre-set as a range in which the power supply cable 2 held by the holding portion 36 of the cable support frame 33 may be crushed by the backward movement of the traveling body 11, assuming that the external power source 1 is disposed on the rear side of the traveling body 11. The range is stored in the controller 50. In the present embodiment, the second range F1 is 360 degrees.

[0086] Assuming that the calculated position of the gripping portion 36 of the cable support frame 33 is not within the second range (however, the second range F1 of the present embodiment is not possible, but the second range F2 of the modified example described later is possible), the process proceeds to step S11. In step S11, the controller 50 controls the reverse locking valves 55A and 55B to be unlocked. Thus, the reverse movement of the traveling body 11 is permitted. On the other hand, if Fig.13A as well as Fig. 13B As shown, when the calculated position of the gripping portion 36 of the cable support 33 is within the second range F1, the process proceeds to step S12. In step S12, the controller 50 controls the reverse locking valves 55A and 55B to be locked, thereby prohibiting the reverse movement of the traveling body 11.

[0087] As described above, the electric excavator of this embodiment can travel (only move forward in this embodiment) even when the feeder cable 2 is connected. However, if there is a possibility that the feeder cable 2 held by the gripping portion 36 of the cable support frame 33 may be crushed by the travel of the travel body 11, the travel action is prohibited. In this way, damage to the feeder cable 2 can be suppressed.

[0088] In addition, in the second embodiment, the first range and the second range set relative to the position of the grip 36 of the cable support frame 33 are fixed, assuming that the external power source 1 is disposed at the rear side of the vehicle 11, but the present invention is not limited thereto. In other words, the first range and the second range set relative to the grip 36 of the cable support frame 33 may be changed according to the configuration of the external power source 1. Fig.14 , Fig.15 , Fig.16A ,as well as Fig. 16B The same reference numerals are used for the parts equivalent to those in the second embodiment, and the description thereof will be omitted as appropriate.

[0089] The electric excavator of this modified example has an input device 51 (see FIG. 1 ) which is disposed in the cabin 29 and can input information about the arrangement of the external power source 1 with respect to the traveling body 11. Fig.14 ).

[0090] The controller 50 further stores the first range E2 and the second range F2 set relative to the position of the gripping portion 36 of the cable support frame 33 (see Fig.15 In the first range E2, the external power source 1 is arranged on the left side of the traveling body 11 ( Fig.15 ) or right side ( Fig.15 The first range F2 is pre-set as a range in which the power feed cable 2 held by the holding portion 36 of the cable support frame 33 may be crushed by the forward movement of the traveling body 11, assuming that the external power source 1 is disposed on the left or right side of the traveling body 11. The second range F3 is pre-set as a range in which the power feed cable 2 held by the holding portion 36 of the cable support frame 33 may be crushed by the backward movement of the traveling body 11, assuming that the external power source 1 is disposed on the left or right side of the traveling body 11.

[0091] The controller 50 changes the first range and the second range according to the configuration of the external power source 1 inputted from the input device 51. For example Fig.16A as well as Fig. 16B As shown, when the external power source 1 inputted by the input device 51 is arranged on the right side of the traveling body 11, the first range E2 and the second range F2 are changed. Fig.16A As shown, when the position of the gripping portion 36 of the cable support frame 33 is in the first range E2, the forward locking valves 54A and 54B are controlled to be locked to prohibit the forward movement of the traveling body 11. Fig. 16B As shown, when the position of the gripping portion 36 of the cable support 33 is in the second range F2, the reverse locking valves 55A and 55B are controlled to be in the locked state, and the reverse movement of the traveling body 11 is prohibited.

[0092] In this modification as well, the same effects as those of the second embodiment can be obtained.

[0093] In addition, in the first embodiment and its modified example and the second embodiment and its modified example, the operating device has a pilot valve that reduces the discharge pressure of the pilot pump 42 according to the operation amount of the operating member and generates a pilot pressure, and outputs the generated pilot pressure to the pressure receiving part of the control valve. However, it is not limited to this. The operating device may also have a potentiometer that detects the operation amount of the operating member and outputs the detection signal to the controller 50. In this modified example, the controller 50 generates a drive signal corresponding to the detection signal of the operating device, and outputs the generated drive signal to the electromagnetic proportional valve. The electromagnetic proportional valve reduces the discharge pressure of the pilot pump 42 according to the drive signal and generates a pilot pressure, and outputs the generated pilot pressure to the pressure receiving part of the control valve. The controller 50 switches the lock valve of the oil circuit provided between the electromagnetic proportional valve and the pressure receiving part of the control valve to a cut-off state and a connected state, or switches the validity and invalidation of the detection signal output from the operating device. Thus, rotation lock control or travel lock control can also be performed. In this modified example, the same effect as above can also be obtained.

[0094] In the first embodiment and its modified example, the case of performing the rotation lock control is described as an example, and in the second embodiment and its modified example, the case of performing the travel lock control is described as an example, but these cases may be combined.

[0095] Furthermore, in the above, the electric excavator is described as an example of an applicable object of the present invention, but the present invention is not limited thereto and can be applied to other electric construction machines.

[0096] Description of Reference Numerals

[0097] 1 External power supply

[0098] 2 Feeder cable

[0099] 11. Travelling body

[0100] 12 Rotating body

[0101] 13 Operating equipment

[0102] 15 Rotation angle sensor

[0103] 31 Feed port

[0104] 32 Connecting Sensors

[0105] 33 Cable support

[0106] 36 Grip

[0107] 37 Rotation angle sensor

[0108] 45A, 45B Rotary Lock Valve (Rotary Lock Device)

[0109] 50 Controller

[0110] 51 Input device

[0111] 54A, 54B Forward Locking Valve (Forward Locking Device)

[0112] 55A, 55B Reverse locking valve (reverse locking device).

Claims

1. An electric construction machine, comprising: a traveling body; a rotating body rotatably provided on the upper side of the traveling body; a working device connected to the rotating body; a power supply port disposed on the rotating body and connected to a power supply cable from an external power source; a cable support frame disposed on the rotating body and having a gripping portion for gripping the power feeding cable, wherein the cable support frame is configured so that the gripping portion can rotate around a vertical axis, The electric construction machine is characterized by having: A connection sensor, which detects a state in which the feeder cable is connected to the feeder port; A rotation angle sensor, which detects the rotation angle of the rotating body; A rotation angle sensor, which detects the rotation angle of the gripping portion of the cable support; A rotation locking device, which is set to a locked state to prohibit the rotational movement of the rotating body; and a controller, which controls the rotation locking device, When the connection sensor detects that the feeding cable is connected to the feeding port, the controller calculates the position of the holding portion of the cable support frame based on the detection results of the rotation angle sensor and the rotation angle sensor, and controls the rotation locking device to a locked state when the calculated position of the holding portion of the cable support frame deviates from a specified range.

2. The electric construction machine according to claim 1, characterized in that: An input device is provided to input the position of the external power source relative to the traveling body, The controller changes the prescribed range according to the configuration of the external power source input by the input device.

3. An electric construction machine, comprising: a traveling body; a rotating body rotatably provided on the upper side of the traveling body; a working device connected to the rotating body; a power supply port disposed on the rotating body and connected to a power supply cable from an external power source; a cable support frame disposed on the rotating body and having a gripping portion for gripping the power feeding cable, wherein the cable support frame is configured so that the gripping portion can rotate around a vertical axis, The electric construction machine is characterized by having: A connection sensor, which detects a state in which the feeder cable is connected to the feeder port; A rotation angle sensor, which detects the rotation angle of the rotating body; A rotation angle sensor, which detects the rotation angle of the gripping portion of the cable support; A forward locking device configured to lock the vehicle in a locked state to prohibit forward movement of the vehicle; A reverse locking device, which is set to a locked state to prohibit the reverse movement of the traveling body; and a controller that controls the forward locking device and the reverse locking device, The controller is configured as follows: When the connection sensor detects that the power cable is connected to the power feed port, the position of the gripping portion of the cable support frame is calculated based on the detection results of the rotation angle sensor and the rotation angle sensor. When the calculated position of the gripping portion of the cable support is within a first range, the forward locking device is controlled to be in a locked state. When the calculated position of the gripping portion of the cable support is within a second range, the retreat locking device is controlled to be in a locked state.

4. The electric construction machine according to claim 3, characterized in that: An input device is provided to input the position of the external power source relative to the traveling body, The controller changes the first range and the second range according to the configuration of the external power source input by the input device.

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