Work machine

Abstract

An electric shovel as a work machine includes an electric motor, a working portion rotated by the electric motor, and a restricting member that restricts rotation of the working portion.

Description

TECHNICAL FIELD

[0001] The present invention relates to a work machine.BACKGROUND ART

[0002] A construction machine including a bucket as an acting portion (working portion) and an electric motor for rotationally driving the bucket is known as a prior art (see, for example, Patent Document 1).PRIOR ART DOCUMENTPatent Document

[0003] Patent Document 1: Japanese Unexamined Patent Publication No. 2021-88834SUMMARY OF INVENTIONTechnical Problem

[0004] The electric motor (specifically, an output shaft of the electric motor) is capable of infinite rotation. Therefore, in the configuration of Patent Document 1, the bucket is infinitely rotationally driven (rotated). However, when the bucket is infinitely rotationally driven, for example, the bucket may unintentionally come into contact with a member other than the bucket inside the construction machine, and the member may be damaged.

[0005] The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a work machine capable of avoiding contact of a working portion with a member different from the working portion by limiting a rotation range of the working portion.Solution to Problem

[0006] A work machine according to one aspect of the present invention includes an electric motor, a working portion rotated by the electric motor, and a restricting member that restricts rotation of the working portion.ADVANTAGEOUS EFFECTS OF INVENTION

[0007] According to the above configuration, it is possible to avoid contact of the working portion with the member different from the working portion by limiting a rotation range of the working portion.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a right side view showing a schematic configuration of an electric shovel that is an example of a work machine according to an embodiment of the present invention.

[0009] FIG. 2 is a block diagram schematically showing a configuration of an electric system of the electric shovel.

[0010] FIG. 3 is a right side view showing a configuration of a working portion included in the electric shovel.

[0011] FIG. 4 is a right side view of the working portion in a posture different from that of FIG. 3.

[0012] FIG. 5 is a perspective view showing a configuration of a restricting member against which the working portion abuts.

[0013] FIG. 6 is a flowchart showing a flow when rotation stop control of the electric motor that rotates the working portion is executed.

[0014] FIG. 7 is a left side view showing a configuration of the working portion in a first modification.

[0015] FIG. 8 is a left side view of the working portion according to the first modification in a posture different from that of FIG. 7.

[0016] FIG. 9 is a right side view showing a configuration of the working portion in a second modification.DESCRIPTION OF EMBODIMENTS

[0017] An embodiment of the present invention will be described below with reference to the drawings.1. Schematic Configuration of Work Machine

[0018] FIG. 1 is a right side view showing a schematic configuration of an electric shovel 1 that is an example of a work machine according to an embodiment of the present invention. The electric shovel 1 includes a machine body 2 and a working portion 3.

[0019] Here, directions used in the description of the present embodiment are defined as follows. One side in one direction when the machine body 2 travels straight along the one direction is referred to as “front”, and the other side is referred to as “rear”. For example, in a direction in which the machine body 2 travels straight along one direction, a side on which the working portion 3 is disposed is referred to as “front”, and the opposite side is referred to as “rear”. In addition, a left side and a right side when viewed from the rear to the front are defined as “left”and “right”, respectively. Furthermore, a gravity direction perpendicular to the front-rear direction and the left-right direction is defined as an up-down direction, an upstream side in the gravity direction is defined as “up”, and a downstream side is defined as “down”. In the drawings, when necessary, forward is denoted by a symbol “F”, backward by “B”, rightward by “R”, leftward by “L”, upward by “U”, and downward by “D”.

[0020] The working portion 3 includes a boom 31, an arm 32, and an attachment 33. By independently driving the boom 31, the arm 32, and the attachment 33, various kinds of work can be performed.

[0021] The boom 31 is rotated by a boom electric motor 31M. The arm 32 is rotated by an arm electric motor 32M. The attachment 33 is rotated by an attachment electric motor 33M. The boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M are each constituted by a synchronous motor, an inductive motor, or the like. The configurations of the boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M are not limited to the above-described types of motors.

[0022] Further, a brake mechanism (not shown) used to decelerate and stop driving (rotation) is incorporated in each of the boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M. The brake mechanism may be provided outside each of the boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M.

[0023] In the present embodiment, the boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M are collectively referred to as electric motors 3M. That is, the electric shovel 1 of the present embodiment includes the electric motor 3M, and the working portion 3 is rotated by the electric motor 3M. The configuration of the working portion 3 will be described in detail later.

[0024] The machine body 2 includes a boom support portion 21. The boom support portion 21 rotatably supports the boom 31. That is, the boom 31 is rotatably coupled to the machine body 2 by the boom support portion 21. The configuration of the boom support portion 21 will be described later.2. Configuration of Electric System

[0025] A configuration of an electric system 5 of the electric shovel 1 will be described with reference to FIG. 2. FIG. 2 is a block diagram schematically showing the configuration of the electric system 5 of the electric shovel 1.

[0026] The electric shovel 1 includes a battery unit 51, an inverter 52, a control device 53, and a sensor 54 as the electric system 5. The electric system 5 includes the electric motor 3M in addition to these devices.

[0027] The battery unit 51 is constituted by, for example, a lithium ion battery, and stores electric power to be supplied to the electric motors 3M (the boom electric motor 31M, the arm electric motor 32M, and the attachment electric motor 33M). The battery unit 51 may be constituted by a plurality of battery cells as a unit or may be constituted by a single battery cell. The inverter 52 converts a DC voltage supplied from the battery unit 51 into an AC voltage and supplies the AC voltage to the electric motor 3M. Thus, the electric motor 3M is driven.

[0028] The control device 53 is constituted by an electronic control unit (ECU). The control device 53 receives a steering command from a steering device (not shown) and electrically controls each part of the electric shovel 1. In particular, the control device 53 controls the rotation of the electric motor 3M. More specifically, an AC voltage is supplied from the inverter 52 to the electric motor 3M based on a rotation command output from the control device 53.

[0029] The sensor 54 is connected to the control device 53. The sensor 54 detects information related to the working portion 3 and outputs the detected information to the control device 53 as a detection result. The sensor 54 includes a first sensor 54a and a second sensor 54b. The configuration of the second sensor 54b will be described later.

[0030] The first sensors 54a are disposed near the boom electric motor 31M, near the arm electric motor 32M, and near the attachment electric motor 33M, respectively. The first sensor 54a located near the boom electric motor 31M detects the rotation angle of the boom 31. The first sensor 54a located near the arm electric motor 32M detects the rotation angle of the arm 32. The first sensor 54a located near the attachment electric motor 33M detects the rotation angle of the attachment 33. The first sensor 54a is, for example, an encoder. That is, the electric shovel 1 includes a first sensor 54a that detects the rotation angle of the working portion 3 (in the present embodiment, the boom 31, the arm 32, and the attachment 33).

[0031] The rotation angle of the working portion 3 detected by the first sensor 54a is output to the control device 53 as a detection result. Based on the rotation angle of the working portion 3, the control device 53 performs control related to stop of the rotation of the electric motor 3M (also simply referred to as rotation stop control). The rotation stop control of the electric motor 3M will be described later.3. Configuration of Working Portion

[0032] The configuration of the working portion 3 will be described with reference to FIGS. 3 and 4. FIGS. 3 and 4 are right side views showing the configuration of the working portion 3. FIG. 3 illustrates a case where the boom 31 abuts against a first restricting member 101 described later, and the arm 32 and the attachment 33 abut against second restricting members 102 described later. FIG. 4 illustrates a case where the boom 31 abuts against the second restricting member 102, and the arm 32 and the attachment 33 abut against the first restricting members 101.

[0033] The boom 31 is formed of a metal hollow member that extends while being curved in one direction (substantially in the up-down direction in FIG. 3). The boom 31 is not limited to the above-described configuration, and may be formed of, for example, a metal solid member.

[0034] A base end portion of the boom 31 is rotatably supported by the boom support portion 21. Further, the base end portion of the boom 31 is coupled to an output shaft 31M1 of the boom electric motor 31M via a boom power transmission portion (not shown). The boom electric motor 31M is fixed to the boom support portion 21 in a direction in which the output shaft 31M1 extends in the left-right direction. The above-described boom power transmission portion includes a speed reduction mechanism, and transmits the rotational power of the output shaft 31M1 of the boom electric motor 31M to the base end portion of the boom 31 while reducing the speed of the rotational power. Therefore, when the boom electric motor 31M is driven and the output shaft 31M1 of the boom electric motor 31M rotates, the boom 31 rotates with respect to the boom support portion 21. Specifically, the boom 31 rotates about a rotation axis (extending in the left-right direction) positioned on the same line as the output shaft 31M1 of the boom electric motor 31M. Thus, the boom 31 rotates in the up-down direction and the front-rear direction with respect to the machine body 2. Note that the boom 31 may be directly coupled to the output shaft 31M1 of the boom electric motor 31M. That is, the boom power transmission portion may be removed.

[0035] The boom support portion 21 includes a plurality of metal plate members that are joined by welding or the like. A restricting member 100 is provided inside the boom support portion 21. In FIGS. 3 and 4, a part of the boom support portion 21 is not shown for the purpose of clarifying the arrangement position of the restricting member 100 located inside the boom support portion 21.

[0036] The restricting member 100 is formed of a rectangular parallelepiped elastic body (for example, rubber). The restricting member 100 is fixed to a member located inside the boom support portion 21 by a fastening member such as a bolt. Accordingly, the restricting member 100 is firmly fixed, and for example, in a case where the restricting member 100 is damaged, the restricting member 100 is easily replaced. The restricting member 100 is not limited to the above-described configuration. For example, the restricting member 100 may be formed of a metal member, or may be formed of a combination of an elastic body and a metal member. Further, the restricting member 100 may have a circular columnar shape or a polygonal columnar shape.

[0037] When the boom 31 is rotated, the boom 31 abuts against the restricting member 100. Thus, the rotation of the boom 31 is stopped. That is, the rotation of the working portion 3 (the boom 31) is restricted by the restricting member 100. More specifically, when the boom 31 is rotated to one side in the rotation direction (counterclockwise when the working portion 3 is viewed from the right) by the driving of the boom electric motor 31M, the first abutment surface 31a of the boom 31 abuts against the restricting member 100 (particularly, see FIG. 3). The first abutment surface 31a is a surface (a surface located on the rear side in FIG. 3) extending in the left-right direction at the base end portion of the boom 31. On the other hand, when the boom 31 is rotated to the other side in the rotation direction (clockwise when the working portion 3 is viewed from the right) by the driving of the boom electric motor 31M, the second abutment surface 31b of the boom 31 abuts against the restricting member 100 (particularly, see FIG. 4). The second abutment surface 31b is a surface (a surface located on the lower side in FIG. 4) extending in the left-right direction that is different from the left-right direction of the first abutment surface 31a at the base end portion of the boom 31.

[0038] In the present embodiment, when the working portion 3 (for example, the boom 31) is rotated to one side in the rotation direction (in the present embodiment, counterclockwise direction when the working portion 3 is viewed from the right side), the restricting member 100 against which the working portion 3 abuts is referred to as a first restricting member 101. That is, the first restricting member 101 restricts the rotation of the working portion 3 to one side in the rotation direction. Further, when the working portion 3 is rotated to the other side in the rotation direction (in the present embodiment, clockwise direction when the working portion 3 is viewed from the right side), the restricting member 100 against which the working portion 3 abuts is referred to as a second restricting member 102. That is, the second restricting member 102 restricts the rotation of the working portion 3 to the other side in the rotation direction. That is, the restricting member 100 of the present embodiment includes the first restricting member 101 and the second restricting member 102.

[0039] The second sensor 54b is attached to an upper portion of the boom support portion 21 via an attachment bracket 54b1 (see FIG. 4 in particular). The attachment bracket 54b1 is formed of a metal plate member extending substantially in the up-down direction.

[0040] The second sensor 54b is disposed at a position overlapping with the boom 31 slightly rotated to the other side in the rotation direction from the position at which the boom 31 abuts against the first restricting member 101 located in the boom support portion 21 when the working portion 3 is viewed from the right side or the left side. The second sensor 54b detects approach of the boom 31 to the first restricting member 101. That is, the electric shovel 1 includes the second sensor 54b that detects the approach of the working portion 3 (the boom 31 in the present embodiment) to the restricting member 100 (the first restricting member 101 in the present embodiment).

[0041] Information detected by the second sensor 54b (information on the approach of the boom 31 to the first restricting member 101) is output to the control device 53 as a detection result. Based on the detection result of the second sensor 54b, the control device 53 conducts the rotation stop control of the boom electric motor 31M.

[0042] A rib 31c is provided at the base end portion of the boom 31. The rib 31c is formed of a substantially triangular metal plate member. In this embodiment, two ribs 31c are provided. One rib 31c is provided on one side (the rear side in FIG. 3) in the rotation direction of the boom 31, and the other rib 31c is provided on the other side (the front side in FIG. 3) in the rotation direction of the boom 31. When the rib 31c is provided as in the present embodiment, even in a configuration in which the boom electric motor 31M (driving power source) is coupled to the base end portion of the boom 31, that is, a configuration in which a large stress is applied to the base end portion of the boom 31, the stress applied to the boom 31 is efficiently dispersed. That is, the strength of the boom 31 is improved by the rib 31c.

[0043] The configuration of the rib 31c is not limited to the above. For example, two ribs 31c may be added in addition to the above-described two ribs 31c. In this case, one of the two ribs 31c to be added may be provided on the left side of the base end portion of the boom 31, and the other of the two ribs 31c to be added may be provided on the right side of the base end portion of the boom 31.

[0044] The first restricting member 101 and the second restricting member 102 against which the arm 32 abuts are provided at the tip end portion of the boom 31 via an angle adjusting member 31d. In the posture of the boom 31 shown in FIG. 3, the first restricting member 101 is positioned rearward of the second restricting member 102. The angle adjusting member 31d is a metal member that enables adjustment of the mounting angles of the first restricting member 101 and the second restricting member 102 against which the arm 32 abuts (positioned at the tip end portion of the boom 31).

[0045] A pair of left and right arm support portions 31e are attached to the tip end portion of the boom 31 by a fastening member such as a bolt. In FIGS. 3 and 4, illustration of the arm support portion 31e on the right side is omitted for the purpose of clarifying the arrangement positions of the first restricting member 101 and the second restricting member 102 located at the tip end portion of the boom 31.

[0046] Each of the left and right arm support portions 31e is formed of a metal plate member extending in a direction in which the tip end portion of the boom 31 extends (in FIG. 3, a direction upward toward the front). The left and right arm support portions 31e rotatably support the arm 32. That is, the arm 32 is coupled to the machine body 2 via the boom 31.

[0047] An arm electric motor 32M is fixed to the left arm support portion 31e. The arm electric motor 32M is connected to a first high-voltage wiring WH1 used for high-voltage power supply and a first low-voltage wiring WL1 used for low-voltage power supply. For example, electric power for driving is supplied to the arm electric motor 32M via the first high-voltage wiring WH1. Electric power (signal) for controlling a brake mechanism incorporated in the arm electric motor 32M is supplied to the arm electric motor 32M via the first low-voltage wiring WL1.

[0048] Each of the first high-voltage wiring WH1 and the first low-voltage wiring WL1 is attached along the surface of the boom 31. For example, the first high-voltage wiring WH1 is disposed along the left end portion on the other side in the rotation direction of the boom 31. The first low-voltage wiring WL1 is disposed along the left end portion on one side in the rotation direction of the boom 31. Therefore, the first high-voltage wiring WH1 and the first low-voltage wiring WL1 can be attached more easily than in the case where the first high-voltage wiring WH1 and the first low-voltage wiring WL1 are attached inside the boom 31. In addition, since the first high-voltage wiring WH1 and the first low-voltage wiring WL1 are disposed separately from each other, it is possible to prevent electrical noise from being added to control power (signal) supplied through the first low-voltage wiring WL1.

[0049] The arm 32 includes an arm main body portion 32a, a first block 32b, and a second block 32c. The arm main body portion 32a is formed of a metal hollow member extending in one direction (in FIG. 3, a direction downward toward the front). More specifically, the arm main body portion 32a is formed by joining a plurality of metal plate members by welding or the like. Specifically, the arm main body portion 32a includes a pair of left and right arm side plates 32a1, an arm upper plate 32a2, and an arm lower plate 32a3. The left and right arm side plates 32al are spaced apart from each other in the left-right direction and extend in the one direction. The arm upper plate 32a2 extends in the left-right direction, and is coupled to one end portions (end portions on the front upper side in FIG. 3) of the left and right arm side plates 32a1 by welding. The arm lower plate 32a3 extends in the left-right direction, and is coupled to the other end portions (end portions on the rear lower side in FIG. 3) of the left and right arm side plates 32a1 by welding.

[0050] The first block 32b is coupled to the base end portion of the arm main body portion 32a by welding. The first block 32b is formed of a metal member extending in the left-right direction. Note that the first block 32b is not limited to a specific shape. In addition, a reinforcing member corresponding to the rib 31c provided in the boom 31 may be provided in a joint portion between the arm main body portion 32a and the first block 32b.

[0051] The first block 32b is rotatably supported by the arm support portion 31e. The first block 32b is coupled to the output shaft 32M1 of the arm electric motor 32M via an arm power transmission portion (not shown). The arm electric motor 32M is fixed to the arm support portion 31e such that the output shaft 32M1 extends in the left-right direction. The above-described arm power transmission portion includes a speed reduction mechanism, and transmits the rotational power of the output shaft 32M1 of the arm electric motor 32M to the first block 32b while reducing the speed of the rotational power. Therefore, when the arm electric motor 32M is driven and the output shaft 32M1 of the arm electric motor 32M rotates, the first block 32b rotates with respect to the arm support portion 31e. Specifically, the first block 32b rotates about a rotation axis (extending in the left-right direction) positioned on the same line as the output shaft 32M1 of the arm electric motor 32M. Thus, the arm 32 rotates in the up-down direction and the front-rear direction with respect to the boom 31.

[0052] When the arm 32 is rotated, the arm 32 abuts against the restricting member 100. Thus, the rotation of the arm 32 is stopped. That is, the rotation of the working portion 3 (arm 32) is restricted by the restricting member 100. More specifically, when the first block 32b is rotated to one side in the rotation direction by the driving of the arm electric motor 32M, a third abutment surface 32b1 of the first block 32b abuts against the first restricting member 101 provided on the boom 31 (particularly, see FIG. 4). The third abutment surface 32b1 is a surface extending in the left-right direction of the first block 32b (a surface positioned on the upper side in FIG. 4). On the other hand, when the first block 32b is rotated to the other side in the rotation direction by the driving of the arm electric motor 32M, a fourth abutment surface 32b2 of the first block 32b abuts against the second restricting member 102 provided on the boom 31 (particularly, see FIG. 3). The fourth abutment surface 32b2 is a surface different from the third abutment surface 32b1 and extending in the left-right direction of the first block 32b (a surface located on the lower side in FIG. 3).

[0053] The second block 32c is coupled to the tip end portion of the arm main body portion 32a by welding. The second block 32c is formed of a metal member extending in the left-right direction. Note that the second block 32c is not limited to a specific shape. The second block 32c is provided with the first restricting member 101 and the second restricting member 102 against which the attachment 33 abuts. In the posture of the arm 32 shown in FIG. 3, the first restricting member 101 is positioned frontward of the second restricting member 102.

[0054] An attachment support portion 32d is attached to the left side of the second block 32c by a fastening member such as a bolt. The attachment support portion 32d is formed of a metal plate member extending in a direction in which the tip end portion of the arm main body portion 32a extends (in FIG. 3, a direction downward toward the right). The attachment support portion 32d rotatably supports the attachment 33. That is, the attachment 33 is rotatably coupled to the arm 32 by the attachment support portion 32d.

[0055] An attachment electric motor 33M is fixed to the attachment support portion 32d. The attachment electric motor 33M is connected to a second high-voltage wiring WH2 used for high-voltage power supply and a second low-voltage wiring WL2 used for low-voltage power supply. For example, electric power for driving is supplied to the attachment electric motor 33M via the second high-voltage wiring WH2. Electric power (signal) for controlling a brake mechanism incorporated in the attachment electric motor 33M is supplied to the attachment electric motor 33M via the second low-voltage wiring WL2.

[0056] The second high-voltage wiring WH2 is attached along the surface of the boom 31 and the surface of the arm 32. The same applies to the second low-voltage wiring WL2. For example, the second high-voltage wiring WH2 is disposed along the left end portion on the other side in the rotation direction of the boom 31, and is disposed along the left end portion on the other side in the rotation direction of the arm 32. That is, the second high-voltage wiring WH2 is disposed together with the first high-voltage wiring WH1 on the surface of the boom 31. The second low-voltage wiring WL2 is disposed along the right end portion on the one side in the rotation direction of the boom 31, and is disposed along the right end portion on the one side in the rotation direction of the arm 32.

[0057] Therefore, the second high-voltage wiring WH2 and the second low-voltage wiring WL2 can be attached more easily than in the case where the second high-voltage wiring WH2 and the second low-voltage wiring WL2 are attached inside the boom 31 and inside the arm 32. In addition, since the second high-voltage wiring WH2 and the second low-voltage wiring WL2 are disposed separately from each other, it is possible to prevent electrical noise from being added to control power (signal) supplied through the second low-voltage wiring WL2. Further, since the first low-voltage wiring WL1 and the second low-voltage wiring WL2 are also disposed separately from each other, it is possible to reliably prevent electrical noise from being added to control power (signal).

[0058] Note that the attachment positions of the first high-voltage wiring WH1, the second high-voltage wiring WH2, the first low-voltage wiring WL1, and the second low-voltage wiring WL2 are not limited to the above. For example, the first high-voltage wiring WH1 and the first low-voltage wiring WL1 may be attached to the inside of the boom 31, and the second high-voltage wiring WH2 and the second low-voltage wiring WL2 may be attached to the inside of the boom 31 and the inside of the arm 32. With this configuration, for example, the first high-voltage wiring WH1, the second high-voltage wiring WH2, the first low-voltage wiring WL1, and the second low-voltage wiring WL2 are protected from earth and sand or the like flying from the vicinity of the attachment 33. In addition, for example, an operator is prevented from erroneously touching the first high-voltage wiring WH1 or the like and getting an electric shock.

[0059] The attachment 33 includes an attachment main body portion 33a and a coupling portion 33b for coupling the attachment main body portion 33a and the attachment support portion 32d. The coupling portion 33b is formed of a metal plate member extending in one direction (substantially in the front-rear direction in FIG. 3). The coupling portion 33b is rotatably supported by the attachment support portion 32d. That is, the coupling portion 33b is coupled to the arm 32.

[0060] In the present embodiment, the attachment main body portion 33a is a bucket used for excavation work of earth and sand or the like. The attachment main body portion 33a may be, for example, a breaker, a grapple, or the like in addition to the bucket.

[0061] The attachment main body portion 33a is replaceably attached to the coupling portion 33b. That is, the attachment main body portion 33a can be replaced with various types. More specifically, the attachment main body portion 33a and the coupling portion 33b are coupled to each other via a coupling shaft portion 33c. That is, the attachment 33 includes the coupling shaft portion 33c that couples the attachment main body portion 33a and the coupling portion 33b. The coupling shaft portion 33c includes a coupling shaft 33c1. The coupling shaft 33c1 is formed of a metal rod member extending in the left-right direction.

[0062] A first mounting hole (not shown) that penetrates in the left-right direction is provided in a base end portion of the attachment main body portion 33a. In addition, a second mounting hole (not shown) that penetrates in the left-right direction is provided in a tip end portion (a portion on a side opposite to a side coupled to the arm 32) of the coupling portion 33b. The coupling shaft 33c1 is inserted into the first mounting hole and the second mounting hole from the right side (or the left side). Then, the coupling shaft 33c1 is fitted into the first mounting hole and the second mounting hole. As a result, the attachment main body portion 33a is attached to the coupling portion 33b. That is, the attachment main body portion 33a is coupled to the coupling portion 33b.

[0063] The coupling portion 33b is coupled to the output shaft 33M1 of the attachment electric motor 33M via an attachment power transmission portion (not shown). The attachment electric motor 33M is fixed to the attachment support portion 32d such that the output shaft 33M1 extends in the left-right direction. The above-described attachment power transmission portion includes a speed reduction mechanism, and transmits the rotational power of the output shaft 33M1 of the attachment electric motor 33M to the coupling portion 33b while reducing the speed of the rotational power. Therefore, when the attachment electric motor 33M is driven and the output shaft 33M1 of the attachment electric motor 33M rotates, the coupling portion 33b rotates with respect to the attachment support portion 32d. Specifically, the coupling portion 33b rotates about a rotation axis (extending in the left-right direction) positioned on the same line as the output shaft 33M1 of the attachment electric motor 33M. Thus, the attachment 33 rotates in the up-down direction and the front-rear direction with respect to the arm 32. Note that the coupling portion 33b may be directly coupled to the output shaft 33M1 of the attachment electric motor 33M. That is, the attachment power transmission portion may be removed.

[0064] When the attachment 33 is rotated, the coupling portion 33b of the attachment 33 abuts against the restricting member 100. Thus, the rotation of the attachment 33 is stopped. That is, the rotation of the working portion 3 (attachment 33) is restricted by the restricting member 100. More specifically, when the coupling portion 33b is rotated to one side in the rotation direction by the driving of the attachment electric motor 33M, a fifth abutment surface 33b1 of the coupling portion 33b abuts against the first restricting member 101 provided on the arm 32 (particularly, see FIG. 4). The fifth abutment surface 33b1 is a surface of the coupling portion 33b that is located on one side (substantially lower side in FIG. 3) in a direction (substantially up-down direction in FIG. 3) orthogonal to the one direction (substantially front-rear direction in FIG. 3) and extends in the left-right direction.

[0065] On the other hand, when the coupling portion 33b is rotated to the other side in the rotation direction by the driving of the attachment electric motor 33M, a sixth abutment surface 33b2 of the coupling portion 33b abuts against the second restricting member 102 provided on the arm 32 (particularly, see FIG. 3). The sixth abutment surface 33b2 is a surface of the coupling portion 33b that is located on the other side (substantially upper side in FIG. 3) in a direction orthogonal to the one direction and extends in the left-right direction.

[0066] According to the above configuration, even when the working portion 3 is rotated, the rotation of the working portion 3 can be restricted (stopped) at a position where the working portion 3 abuts against the restricting member 100. That is, the rotation range of the working portion 3 can be limited.

[0067] Thus, the rotation range of the working portion 3 can be set so that the working portion 3 rotates in the rotation range excluding a range of a member different from the working portion 3 (for example, a member other than the working portion 3 inside the electric shovel 1). Therefore, even when the working portion 3 is rotated, it is possible to avoid contact of the working portion 3 with the member. As described above, it is possible to prevent the working portion 3 from coming into contact with a member different from the working portion 3 by limiting the rotation range of the working portion 3.

[0068] The following configuration is desirable from the viewpoint of limiting both the rotation range on one side in the rotation direction of the working portion 3 (in the present embodiment, the counterclockwise direction when the working portion 3 is viewed from the right) and the rotation range on the other side in the rotation direction (in the present embodiment, the clockwise direction when the working portion 3 is viewed from the right). That is, as in the present embodiment, it is desirable that the restricting member 100 includes the first restricting member 101 that restricts the rotation of the working portion 3 on one side in the rotation direction and the second restricting member 102 that restricts the rotation of the working portion 3 on the other side in the rotation direction.

[0069] In the configuration in which the working portion 3 includes the arm 32 and the attachment 33 including the coupling portion 33b coupled to the arm 32, the following configuration is desirable from the viewpoint of limiting the rotation range of the attachment 33 with a small number of components by effectively utilizing the coupling portion 33b. That is, as in the present embodiment, when the attachment 33 is rotated, it is desirable that the coupling portion 33b abuts against the restricting member 100.

[0070] Here, the configuration of the restricting member 100 will be described in detail with reference to FIG. 5. FIG. 5 is a perspective view showing a configuration of the restricting member 100. In FIG. 5, for the purpose of describing the configuration of the restricting member 100, directions different from the above-described directions (the front-rear direction, the left-right direction, and the up-down direction) of the electric shovel 1 are indicated by broken-line arrows. That is, in FIG. 5, an F1-B1 direction and an L1-R1 direction that are orthogonal to each other, and a U1-D1 direction that is perpendicular to the F1-B1 direction and the L1-R1 direction are indicated by dashed arrows.

[0071] As described above, the restricting member 100 is formed of a rectangular parallelepiped elastic body. More specifically, the restricting member 100 includes a planar portion 100a, an attachment surface portion 100b that is parallel to the planar portion 100a and is located away from the planar portion 100a in one direction (in FIG. 5, the U1-D1 direction), and a side surface portion 100c that is connected to a peripheral edge portion of the planar portion 100a and a peripheral edge portion of the attachment surface portion 100b.

[0072] When the restricting member 100 is attached, a direction in which the restricting member 100 is attached is a direction in which the attachment surface portion 100b and a portion to which the restricting member 100 is to be attached come into contact with each other. For example, in the restricting member 100 provided on the second block 32c (see FIGS. 3 and 4) of the arm 32, the restricting member 100 is attached (fixed) such that the attachment surface portion 100b is in contact with the second block 32c. In addition, the restricting member 100 is disposed such that the planar portion 100a is parallel to each portion (for example, the fifth abutment surface 33b1 of the attachment 33) of the working portion 3 which abuts against the restricting member 100 when the working portion 3 abuts against the restricting member 100. Therefore, for example, when the attachment 33 is rotated and the attachment 33 (in particular, the coupling portion 33b) abuts against the restricting member 100 (the first restricting member 101 or the second restricting member 102), the attachment 33 abuts against the planar portion 100a of the restricting member 100. That is, the working portion 3 (for example, the attachment 33) abuts against the planar portion 100a of the restricting member 100.

[0073] When the working portion 3 abuts against the planar portion 100a, an impact stress applied to the restricting member 100 is reduced compared to a case where, for example, the working portion 3 abuts against a corner portion (not illustrated) of the restricting member 100. From this viewpoint, as in the present embodiment, it is desirable that the restricting member 100 has a planar portion 100a against which the working portion 3 abuts.

[0074] As described above, in the present embodiment, the restricting member 100 is formed of an elastic body. Therefore, the planar portion 100a of the restricting member 100 is formed of the elastic body.

[0075] From the viewpoint of reliably reducing the impact stress applied to the restricting member 100 when the working portion 3 abuts against the restricting member 100, it is desirable that the planar portion 100a is formed of an elastic body as in the present embodiment.

[0076] Further, as described above, the restricting member 100 is replaceably attached. Therefore, the rotation range of the working portion 3 can be easily adjusted by replacing the restricting member 100 with another restricting member 100 having a different size, shape, or the like.4. Rotation Stop Control of Electric Motor

[0077] The rotation stop control of the electric motor 3M will be described. Hereinafter, as an example, the rotation stop control of the boom electric motor 31M will be described with reference to FIG. 6. FIG. 6 is a flowchart showing a flow when the rotation stop control of the boom electric motor 31M is executed. In the step S0, it is assumed that the rotation angle of the boom 31 is within a predetermined range and the boom 31 is rotated toward one side in the rotation direction (in the present embodiment, the counterclockwise direction when the working portion 3 is viewed from the right side).

[0078] In the step S1, the first sensor 54a (see FIG. 2) located near the boom electric motor 31M detects the rotation angle of the boom 31. As described above, the first sensor 54a outputs the detected rotation angle of the boom 31 to the control device 53. When the rotation angle of the boom 31 is output to the control device 53, the process proceeds to the next step S2.

[0079] In the present embodiment, the rotation angle of the boom 31 means a rotation angle with respect to the machine body 2. Further, the rotation angle of the arm 32 means a rotation angle with respect to the boom 31, and the rotation angle of the attachment 33 means a rotation angle with respect to the arm 32.

[0080] In the step S2, the control device 53 determines whether or not the rotation angle of the boom 31 output from the first sensor 54a is out of a predetermined range. In the present embodiment, the predetermined range described above is set, for example, between 90 degree upward from the horizontal direction and 20 degrees downward from the horizontal direction, and is stored in the control device 53. When the rotation angle of the boom 31 is out of the predetermined range (Yes in step S2), the process proceeds to the next step S3. When the rotation angle of the boom 31 is not out of the predetermined range, that is, when the rotation angle is within the predetermined range (No in step S2), the process is returned to the step S1.

[0081] In the step S3, the control device 53 starts the first rotation stop control for the boom electric motor 31M. In the present embodiment, in the first rotation stop control described above, the control device 53 outputs, to the inverter 52 (see FIG. 2), a rotation command for stopping the generation of the rotational power in the boom electric motor 31M (the output shaft 31M1 of the boom electric motor 31M). As a result, the rotation of the boom electric motor 31M is stopped. At this time, the boom 31 is spaced apart from the first restricting member 101 located in the boom support portion 21. That is, the boom 31 does not abut against the first restricting member 101. Therefore, the control device 53 executes the following when the rotation angle of the working portion 3 detected by the first sensor 54a is out of the predetermined range before the working portion 3 (the boom 31 in the present embodiment) abuts against the restricting member 100 (the first restricting member 101 in the present embodiment). That is, the control device 53 stops the rotation of the electric motor 3M (the boom electric motor 31M in the present embodiment). When the first rotation stop control is started, the process proceeds to the next step S4.

[0082] In the step S4, the control device 53 determines whether or not the boom 31 (the rotation of the boom 31) is stopped. In the present embodiment, the determination described above is made based on the rotation angle of the boom 31 output from the first sensor 54a. For example, when the rotation angle of the boom 31 is the same as the rotation angle of the boom 31 before a predetermined time (for example, one second), it is determined that the boom 31 is stopped. On the other hand, when the rotation angle of the boom 31 is different from the rotation angle of the boom 31 before the predetermined time, it is determined that the boom 31 is rotating (not stopped). When the boom 31 is stopped (Yes in step S4), the first rotation stop control is ended (see step S5). When the boom 31 is rotating, that is, when the boom 31 is not stopped (No in step S4), the process proceeds to the step S6.

[0083] In the step S6, the control device 53 determines whether or not an emergency stop command for the boom 31 has been issued. In the present embodiment, the emergency stop command is realized by the second sensor 54b (see FIG. 2 and FIG. 4) detecting the approach of the boom 31 to the first restricting member 101 (see FIG. 3 and FIG. 4) positioned inside the boom support portion 21. When the emergency stop command for the boom 31 has been issued (Yes in step S6), the process proceeds to the next step S7. When the emergency stop command for the boom 31 has not been issued (No in step S6), the process is returned to the step S3.

[0084] In the step S7, the control device 53 starts the second rotation stop control for the boom electric motor 31M. In the present embodiment, the above-described brake mechanism incorporated in the boom electric motor 31M is operated in the second rotation stop control. As a result, the rotation of the boom electric motor 31M is stopped. At this time, the boom 31 is spaced apart from the first restricting member 101 located in the boom support portion 21. That is, the boom 31 does not abut against the first restricting member 101. Therefore, the control device 53 executes the following based on the detection result of the second sensor 54b (the approach of the boom 31 to the first restricting member 101) before the working portion 3 (the boom 31 in the present embodiment) abuts against the restricting member 100 (the first restricting member 101 in the present embodiment). That is, the control device 53 stops the rotation of the electric motor 3M (the boom electric motor 31M in the present embodiment). When the second rotation stop control is started, the process proceeds to the next step S8.

[0085] In the step S8, similarly to the step S4, the control device 53 determines whether or not the boom 31 (the rotation of the boom 31) is stopped. Since the process of the step S8 is the same as the process of the step S4, the description thereof will be omitted here.

[0086] As described above, in the present embodiment, the first restricting member 101 (disposed inside the boom support portion 21) is provided so that the boom 31 rotating to one side in the rotation direction (in the present embodiment, in the counterclockwise direction when the boom 31 is viewed from the right side) abuts against the first restricting member 101. For this reason, even when at least one of the first rotation stop control and the second rotation stop control is executed, for example, due to the inertia of the boom 31, the rotation of the boom 31 may continue. In this case, the boom 31 abuts against the first restricting member 101, and thus the rotation of the boom 31 is stopped.

[0087] When the boom 31 (the rotation of the boom 31) is stopped (Yes in step S8), the second rotation stop control is ended (see step S9), and the first rotation stop control is ended (see step S5). When the boom 31 is rotating, that is, when the boom 31 is not stopped (No in step S8), the process is returned to the step S7.

[0088] As described above, in the present embodiment, the first sensor 54a is disposed not only near the boom electric motor 31M but also near the arm electric motor 32M and near the attachment electric motor 33M. Therefore, the first rotation stop control described above can also be applied to the arm electric motor 32M and the attachment electric motor 33M.

[0089] Further, for example, when the second sensor 54b is disposed at a position overlapping with the boom 31 slightly rotated to one side in the rotation direction from the position at which the boom 31 abuts against the second restricting member 102 in the boom support portion 21 when the working portion 3 is viewed from the right side or the left side, the following can be performed. That is, the second rotation stop control can be applied to the boom 31 rotated toward the other side in the rotation direction (in the present embodiment, the clockwise direction when the working portion 3 is viewed from the right side). Further, since the second rotation stop control is applied to the arm 32 and the attachment 33, the second sensor 54b may be added.

[0090] The following configuration is desirable from the viewpoint of limiting the rotation range of the working portion 3 (for example, the boom 31) by controlling the rotation of the electric motor 3M (for example, the boom electric motor 31M) in accordance with the rotation angle of the working portion 3. That is, as in the present embodiment, it is desirable that the electric shovel 1 includes the first sensor 54a that detects the rotation angle of the working portion 3 and the control device 53 that controls the rotation of the electric motor 3M. In addition, in a case where the rotation range of the working portion 3 is limited, it is desirable that the working portion 3 does not abut against the restricting member 100 (for example, the first restricting member 101 positioned in the boom support portion 21), and work by the working portion 3 is prevented from being hindered by the limitation of the rotation range of the working portion 3. From this viewpoint, as in the present embodiment, it is desirable that the control device 53 stops the rotation of the electric motor 3M when the rotation angle of the working portion 3 is out of the predetermined range before the working portion 3 abuts against the restricting member 100.

[0091] In the configuration in which the electric shovel 1 includes the second sensor 54b that detects the approach of the working portion 3 (the boom 31 in the present embodiment) to the restricting member 100, the following configuration is desirable from the viewpoint of reliably limiting the rotation range of the working portion 3 while preventing the working portion 3 from abutting against the restricting member 100. That is, as in the present embodiment, it is desirable that the control device 53 stops the rotation of the electric motor 3M (in the present embodiment, the boom electric motor 31M) based on the detection result of the second sensor 54b before the working portion 3 abuts against the restricting member 100.

[0092] Note that the configuration of the first rotation stop control and the configuration of the second rotation stop control may be reversed. That is, the above-described brake mechanism incorporated in the boom electric motor 31M may be operated as the first rotation stop control. As the second rotation stop control, the control device 53 may output a rotation command for stopping the generation of the rotational power in the boom electric motor 31M.

[0093] In the present embodiment, the configuration in which the sensor 54 (the first sensor 54a and the second sensor 54b) is provided separately from the restricting member 100 has been described, but the present invention is not limited to the above-described configuration. For example, the sensor 54 may be incorporated in the restricting member 100 itself. In this case, the sensor 54 may be, for example, a contact sensor that detects stress (impact stress) applied to the restricting member 100 and detects that the working portion 3 has abutted against the restricting member 100, that is, the working portion 3 has come into contact with the restricting member 100.

[0094] Further, the control device 53 may execute at least one of the first rotation stop control and the second rotation stop control based on the detection result output from the contact sensor. This prevents the working portion 3 from continuously pressing the restricting member 100 and damaging the restricting member 100.5. Modification of Working Portion

[0095] Hereinafter, modifications of the working portion 3 will be described.5-1. First Modification

[0096] A first modification of the working portion 3 will be described with reference to FIGS. 7 and 8. FIGS. 7 and 8 are left side views showing the configuration of the working portion 3 according to the first modification. FIG. 7 illustrates a case where the attachment 33 abuts against the first restricting member 101. FIG. 8 illustrates a case where the attachment 33 abuts against the second restricting member 102 (a recessed portion 32e of the arm 32 to be described later). The working portion 3 shown in FIGS. 7 and 8 has the same configuration as that of the working portion 3 shown in FIGS. 3 and 4 except that the configuration of the arm 32 (particularly, the arm main body portion 32a and the attachment support portion 32d) is different. That is, the attachment 33 shown in FIGS. 7 and 8 includes an attachment main body portion 33a, a coupling portion 33b, and a coupling shaft portion 33c (coupling shaft 33cl). Although the base end portion of the arm 32 is not shown in FIGS. 7 and 8 for the sake of convenience, the base end portion of the arm 32 has the same configuration as the base end portion of the arm 32 shown in FIGS. 3 and 4.

[0097] In the first modification, the arm main body portion 32a includes a metal plate member extending in one direction (the front-rear direction in FIGS. 7 and 8) and a direction orthogonal to the one direction (the up-down direction in FIGS. 7 and 8). Hereinafter, a direction orthogonal to the one direction may be referred to as an orthogonal direction.

[0098] In the arm main body portion 32a, a recessed portion 32e is formed at an end portion on one side (lower side in FIGS. 7 and 8) in the orthogonal direction. The recessed portion 32e is recessed toward the other side in the orthogonal direction (upward in FIGS. 7 and 8) in a shape along the outer peripheral surface of the coupling shaft 33c1 of the coupling shaft portion 33c.

[0099] A first restricting member 101 is attached to a left side surface portion of the arm main body portion 32a. In the first modification, the first restricting member 101 includes a base portion 101a formed of a rectangular parallelepiped metal member and a buffer member 101b formed of a flat plate-shaped elastic body (for example, rubber). The buffer member 101b is attached to at least one of the plurality of surfaces of the base portion 101a by an adhesive or the like. In the first modification, the buffer member 101b is attached to one surface (the front surface in FIGS. 7 and 8) of the plurality of surfaces of the base portion 101a.

[0100] The attachment 33 (in particular, the coupling portion 33b) is rotatably coupled to the left side of the tip end portion of the arm main body portion 32a. That is, in the first modification, the arm main body portion 32a and the attachment support portion 32d are integrally formed. That is, the arm main body portion 32a includes the attachment support portion 32d. Further, the attachment electric motor 33M is fixed to the right side of the tip end portion of the arm main body portion 32a.

[0101] When the attachment 33 is rotated to the one side in the rotation direction by the driving of the attachment electric motor 33M, the fifth abutment surface 33b1 of the coupling portion 33b abuts against the first restricting member 101 attached to the arm 32 (particularly, see FIG. 7). As in the case shown in FIGS. 3 and 4, also in the first modification, the one side in the rotation direction means the clockwise direction when the working portion 3 is viewed from the left, that is, the counterclockwise direction when the working portion 3 is viewed from the right. Further, the other side in the rotation direction means the counterclockwise direction when the working portion 3 is viewed from the left, that is, the clockwise direction when the working portion 3 is viewed from the right.

[0102] On the other hand, when the attachment 33 is rotated to the other side in the rotation direction by the driving of the attachment electric motor 33M, the coupling shaft 33c1 of the coupling shaft portion 33c abuts against the recessed portion 32e formed in the arm 32 (particularly, see FIG. 8).

[0103] Therefore, in the first modification, the recessed portion 32e functions to limit the rotation range of the attachment 33 that rotates to the other side in the rotation direction. That is, the recessed portion 32e constitutes the second restricting member 102 that restricts the rotation of the working portion 3 to the other side in the rotation direction. That is, in the first modification, the second restricting member 102 includes the recessed portion 32e.

[0104] In the configuration in which the attachment 33 includes the attachment main body portion 33a, the coupling portion 33b, and the coupling shaft portion 33c, the following configuration is desirable from the viewpoint of limiting the rotation range of the attachment 33 with a small number of components by effectively utilizing the coupling portion 33b and the coupling shaft portion 33c. That is, as in the first modification, when the attachment 33 is rotated to one side in the rotation direction (in the first modification, clockwise direction when the working portion 3 is viewed from the left side), it is desirable that the coupling portion 33b abuts against the first restricting member 101. In addition to this, when the attachment 33 is rotated to the other side in the rotation direction (in the first modification, counterclockwise direction when the working portion 3 is viewed from the left side), it is desirable that the coupling shaft portion 33c abuts against the second restricting member 102.

[0105] By changing the length (the depth of the recessed portion 32e) of the recessed portion 32e in the orthogonal direction (the up-down direction in FIGS. 7 and 8), it is possible to easily adjust the rotation range of the attachment 33 (particularly, the rotation range when the attachment 33 rotates to the other side in the rotation direction). Further, as described above, the recessed portion 32e is formed in a shape along the outer peripheral surface of the coupling shaft 33c1. Thus, when the coupling shaft 33c1 abuts against the recessed portion 32e, the area of contact between the recessed portion 32e and the coupling shaft 33c1 is increased, and impact stress applied to the recessed portion 32e and the coupling shaft 33c1 is alleviated. Therefore, from the viewpoint of facilitating the adjustment of the rotation range of the attachment 33 and alleviating the impact stresses applied to the arm 32 and the coupling shaft portion 33c, it is desirable that the second restricting member 102 includes the recessed portion 32e against which the coupling shaft portion 33c abuts as in the first modification.

[0106] 5-2. Second Modification

[0107] A second modification of the working portion 3 will be described with reference to FIG. 9. FIG. 9 is a right side view showing a configuration of the working portion 3 (arm 32) according to the second modification. The working portion 3 shown in FIG. 9 has the same configuration as that of the working portion 3 shown in FIGS. 3 and 4 except that the configuration of the arm 32 (particularly, the arm main body portion 32a) is different.

[0108] In the second modification, similarly to the arm main body portion 32a shown in FIGS. 3 and 4, the arm main body portion 32a is formed of a metal hollow member extending in one direction (front-rear direction in FIG. 9). However, the arm main body portion 32a of the second modification becomes thinner toward one side (front side in FIG. 9) in the one direction. More specifically, the pair of left and right arm side plates 32a1 are spaced apart from each other in the left-right direction. The lengths (widths) of the left and right arm side plates 32a1 in a direction orthogonal to the one direction (the up-down direction in FIG. 9) decrease toward the one side in the one direction. The arm upper plate 32a2 is inclined toward one side in a direction orthogonal to the one direction (downward in FIG. 9) as the arm upper plate 32a2 extends toward the one side in the one direction. The arm upper plate 32a2 is coupled to one end portions (upper end portions in FIG. 9) of the left and right arm side plates 32a1. The arm lower plate 32a3 is inclined toward the other side in a direction orthogonal to the one direction (upward in FIG. 9) as the arm lower plate 32a3 extends toward the one side in the one direction. The arm lower plate 32a3 is coupled to the other end portions (lower end portions in FIG. 9) of the left and right arm side plates 32a1.

[0109] Therefore, in the second modification, the section modulus of the cross section perpendicular to one direction in the arm main body portion 32a is larger on the base end portion side (the rear side in FIG. 9) than on the tip end portion side (the front side in FIG. 9). For this reason, according to the configuration of the arm 32 (arm main body portion 32a) of the second modification, even when the reinforcing member corresponding to the rib 31c of the boom 31 shown in FIGS. 3 and 4 is not provided, the stress applied to the base end portion of the arm 32 is efficiently dispersed. That is, the strength of the arm 32 is improved with a small number of components. However, even in the arm 32 of the second modification, the reinforcing member described above may be provided (in particular, at the joining portion between the arm main body portion 32a and the first block 32b).

[0110] In the configuration in which the arm electric motor 32M (driving power source) is coupled to the base end portion of the arm 32, the stress applied to the tip end portion of the arm 32 is smaller than the stress applied to the base end portion of the arm 32. Therefore, according to the configuration of the arm 32 (arm main body portion 32a) of the second modification, the weight of the arm 32 is reduced while ensuring the strength of the tip end portion of the arm 32.6. Supplementary Description

[0111] In the present embodiment, for example, a configuration has been described in which the restricting member 100 that restricts the rotation range of the boom 31 is disposed at a location different from the boom 31, but the present invention is not limited to the above-described configuration. For example, the restricting member 100 that restricts the rotation range of the boom 31 may be disposed on the boom 31 itself. The same applies to the restricting member 100 that restricts the rotation of the arm 32 and the restricting member 100 that restricts the rotation range of the attachment 33.

[0112] The electric shovel 1 may include a steering portion on which an operator can steer the electric shovel 1.

[0113] In this embodiment, although the electric shovel 1 has been described above as an example of a work machine, the work machine is not limited to the electric shovel 1, and may be a construction machine such as a hydraulic shovel or a wheel loader. Moreover, the work machine may be an agricultural machine such as a combine, a tractor and the like.7. Supplementary Notes

[0114] The electric shovel 1 described in this embodiment can also be expressed as a work machine as described in the following appendices.

[0115] The work machine according to appendix (1) comprises:

[0116] an electric motor;

[0117] a working portion rotated by the electric motor; and

[0118] a restricting member that restricts rotation of the working portion.

[0119] The work machine according to appendix (2) is the work machine according to appendix (1), wherein:

[0120] the restricting member includes

[0121] a first restricting member that restricts rotation of the working portion on one side in the rotation direction; and

[0122] a second restricting member that restricts rotation of the working portion on an other side in the rotation direction.

[0123] The work machine according to appendix (3) is the work machine according to appendix (2), wherein:

[0124] the working portion includes

[0125] an arm, and

[0126] an attachment rotatably coupled to the arm, and

[0127] the attachment includes a coupling portion connected to the arm, and

[0128] the coupling portion abuts against the restricting member when the attachment is rotated.

[0129] The work machine according to appendix (4) is the work machine according to appendix (3), wherein:

[0130] the attachment includes

[0131] an attachment main body portion coupled to the coupling portion; and

[0132] a coupling shaft portion coupling the attachment main body portion and the coupling portion, and

[0133] the coupling portion abuts against the first restricting member when the attachment is rotated to the one side in the rotation direction, and

[0134] the coupling shaft portion abuts against the second restricting member when the attachment is rotated to the other side in the rotation direction.

[0135] The work machine according to appendix (5) is the work machine according to appendix (4), wherein

[0136] the second restricting member includes a recessed portion against which the coupling shaft portion abuts.

[0137] The work machine according to appendix (6) is the work machine according to any one of appendices (1) to (5), wherein

[0138] the restricting member has a planar portion against which the working portion abuts.

[0139] The work machine according to appendix (7) is the work machine according to appendix (6), wherein the planar portion is formed of an elastic body.

[0140] The work machine according to appendix (8) is the work machine according to any one of appendices (1) to (7), comprising

[0141] a first sensor that detects a rotation angle of the working portion; and

[0142] a control device that controls rotation of the electric motor, wherein

[0143] the control device stops the electric motor when a rotation angle of the working portion is out of a predetermined range before the working portion abuts against the restricting member.

[0144] The work machine according to appendix (9) is the work machine according to appendix (8), comprising

[0145] a second sensor that detects an approach of the working portion to the restricting member,

[0146] wherein the control device stops the electric motor based on a detection result of the second sensor before the working portion abuts against the restricting member.

[0147] Although the embodiment of the present invention has been described above, the scope of the invention is not limited thereto, and can be expanded or modified without deviating from the gist of the present invention.INDUSTRIAL APPLICABILITY

[0148] The present invention is applicable to work machines such as a construction machine and an agricultural machine, for example.REFERENCE SIGNS LIST1 electric shovel (work machine)

[0150] 3 working portion

[0151] 3M electric motor

[0152] 32 arm

[0153] 32e recessed portion

[0154] 33 attachment

[0155] 33a attachment main body portion

[0156] 33b coupling portion

[0157] 33c coupling shaft portion

[0158] 53 control device

[0159] 54a first sensor

[0160] 54b second sensor

[0161] 100 restricting member

[0162] 100a planar portion

[0163] 101 first restricting member

[0164] 102 second restricting member

Claims

1. A work machine comprising:an electric motor;a working portion rotated by the electric motor; anda restricting member that restricts rotation of the working portion.

2. The work machine according to claim 1, wherein the restricting member includes:a first restricting member that restricts rotation of the working portion on one side in a rotation direction; anda second restricting member that restricts rotation of the working portion on an other side in the rotation direction.

3. The work machine according to claim 2, wherein the working portion includes:an arm, andan attachment rotatably coupled to the arm, andwherein:the attachment includes a coupling portion connected to the arm, andthe coupling portion abuts against the restricting member when the attachment is rotated.

4. The work machine according to claim 3, wherein the attachment includes:an attachment main body portion coupled to the coupling portion; anda coupling shaft portion coupling the attachment main body portion and the coupling portion, andwherein:the coupling portion abuts against the first restricting member when the attachment is rotated to the one side in the rotation direction, andthe coupling shaft portion abuts against the second restricting member when the attachment is rotated to the other side in the rotation direction.

5. The work machine according to claim 4, wherein the second restricting member includes a recessed portion against which the coupling shaft portion abuts.

6. The work machine according to claim 1, wherein the restricting member has a planar portion against which the working portion abuts.

7. The work machine according to claim 6, wherein the planar portion is formed of an elastic body.

8. The work machine according to claim 1, comprising:a first sensor that detects a rotation angle of the working portion; anda control device that controls rotation of the electric motor, wherein the control device stops the electric motor when a rotation angle of the working portion is out of a predetermined range before the working portion abuts against the restricting member.

9. The work machine according to claim 8, comprising a second sensor that detects an approach of the working portion to the restricting member,wherein the control device stops the electric motor based on a detection result of the second sensor before the working portion abuts against the restricting member.

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