Work machine

Abstract

The present invention provides a work machine capable of improving the degree of freedom in the design around the telescopic boom and the reliability during boom telescoping. The work machine includes: a telescoping actuator that moves a first arm relative to a second arm in the telescoping direction; an electric drive source disposed on a movable part of the telescoping actuator; a first fixing pin that connects the telescoping actuator and the first arm; a first connecting mechanism that switches the connection state between the telescoping actuator and the first arm based on the power of the electric drive source; a second fixing pin that connects the first arm and the second arm; a second connecting mechanism that switches the connection state between the first arm and the second arm based on the power of the electric drive source; and a torque limiter disposed between the electric drive source and the first connecting mechanism or the second connecting mechanism, which keeps the load acting on a mechanical element, which constitutes a power transmission path starting from the electric drive source, below a specified value.

Description

Technical Field

[0001] The present invention relates to a working machine having a telescopic boom. Background Art

[0002] Conventionally, a mobile crane having a telescopic boom has been known, in which a plurality of boom elements of the telescopic boom are overlapped and arranged in a nested shape (also referred to as "telescopic shape") (for example, refer to Patent Document 1). The telescopic boom is configured to be able to be telescopically extended and retracted step by step by a telescopic actuator disposed inside the innermost boom element.

[0003] Specifically, in the telescopic boom, adjacent boom elements inside and outside are connected to each other by a boom connection pin (hereinafter referred to as "B pin"). If the connection made by the B pin is released, the inner boom element can move relative to the outer boom element in the telescopic direction. The movable boom element is connected to the movable part of the telescopic actuator by an oil cylinder connection pin (hereinafter referred to as "C pin"). The telescopic actuator is constituted by, for example, a hydraulic cylinder having a piston rod portion and an oil cylinder portion, and the oil cylinder portion functions as a movable part to extend and retract the boom element.

[0004] In addition, the insertion and removal operations of the B pin and the C pin are exclusively controlled by a pin insertion / removal actuator provided in the movable part of the telescopic actuator, and the connection state between the boom elements made by the B pin and the connection state between the oil cylinder and the boom made by the C pin cannot be released simultaneously (so-called "interlock").

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-96928 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, conventionally, a hydraulic actuator has been used as the pin insertion / removal actuator, and pipes and a hydraulic circuit for supplying working oil to the actuator are provided around the telescopic boom. Therefore, the design around the telescopic boom is restricted in space, and it may be possible to restrict the miniaturization and weight reduction of the telescopic boom.

[0010] In addition, the viscosity of the working oil changes according to the ambient temperature and the like. Therefore, the operation time is unstable, and particularly in a low-temperature environment, the influence is large, resulting in poor operation.

[0011] An object of the present invention is to provide a working machine capable of improving the degree of freedom in the design around the telescopic boom and the reliability during boom extension and retraction.

[0012] Means for Solving the Problems

[0013] A work machine according to the present invention includes:

[0014] A telescopic arm having a first arm and a second arm that overlap in a telescopic manner;

[0015] A telescopic actuator that moves the first arm relative to the second arm in the telescopic direction;

[0016] An electric drive source provided on a movable part of the telescopic actuator;

[0017] A first fixing pin that connects the telescopic actuator and the first arm;

[0018] A first connecting mechanism that operates by the power of the electric drive source to insert and remove the first

[0019] fixing pin, thereby switching the connection state and the non-connection state between the telescopic actuator and the first arm;

[0020] A second fixing pin that connects the first arm and the second arm;

[0021] A second connecting mechanism that operates by the power of the electric drive source to insert and remove the second

[0022] fixing pin, thereby switching the connection state and the non-connection state between the first arm and the second arm;

[0023] And

[0024] A torque limiter disposed between the electric drive source and the first connecting mechanism or the second connecting mechanism, and keeping the load acting on a mechanical element that constitutes a power transmission path from the electric drive source to the first connecting mechanism or the second connecting mechanism below a specified value.

[0025] Advantages of the Invention

[0026] According to the present invention, it is possible to achieve an increase in the degree of freedom in the design around the telescopic arm and the reliability during arm telescoping. Brief Description of the Drawings

[0027] Figure 1 is a view showing a state of a mobile crane according to an embodiment of the present invention during traveling.

[0028] Figure 2 is a view showing a state of the mobile crane during operation.

[0029] Figures 3A - 3C is a schematic view for explaining the structure of the telescopic arm and the extending operation.

[0030] Figures 4A - 4CIt is a schematic diagram for explaining the structure of the telescopic arm and the extending operation.

[0031] Figure 5 It is a perspective view of the entire telescopic device.

[0032] Figure 6 It is a perspective view of the actuator for pin insertion / extraction.

[0033] Figure 7 It is a plan view of the actuator for pin insertion / extraction observed from the + side in the Z direction.

[0034] Figure 8 It is a side view of the actuator for pin insertion / extraction observed from the + side in the Y direction.

[0035] Figure 9 It is a perspective view showing the state where the actuator for pin insertion / extraction is engaged with the B-pin holding part.

[0036] Figure 10 It is a front view of the state where the actuator for pin insertion / extraction is engaged with the B-pin holding part observed from the - side in the X direction.

[0037] Figure 11 It is a diagram showing the internal structure of the actuator for pin insertion / extraction.

[0038] Figure 12 It is a diagram showing the internal structure of the actuator for pin insertion / extraction.

[0039] Figure 13 It is a diagram showing the internal structure of the actuator for pin insertion / extraction.

[0040] Figure 14 It is a diagram schematically showing the structure of the actuator for pin insertion / extraction.

[0041] Figure 15A 、 Figure 15B It is a diagram showing the withdrawn state of the oil cylinder connection module and the withdrawn state of the arm connection module.

[0042] Figures 16A - 16C It is a schematic diagram for explaining the operation and function of the locking mechanism.

[0043] Figures 17A - 17C It is a schematic diagram for explaining the operation of the oil cylinder connection module.

[0044] Figures 18A - 18C It is a schematic diagram for explaining the operation of the arm connection module.

[0045] Figure 19 It is a timing diagram showing an example of the control during the extending operation of the telescopic arm.

[0046] Figure 20This is a timing chart showing an example of the control of the telescopic boom to which motor assistance processing is applied during the extending operation. Detailed Embodiment

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0048] In the present embodiment, a mobile crane 1 as an example of a working machine according to the present invention will be described.

[0049] <Mobile Crane>

[0050] Figure 1 This is a view showing the state of the mobile crane 1 according to an embodiment of the present invention during traveling. Figure 2 This is a view showing the state of the mobile crane 1 during operation. Figure 1 、 Figure 2 The mobile crane 1 shown is a so-called rough terrain crane having an upper slewing body 10 and a lower traveling body 20.

[0051] The upper slewing body 10 includes a slewing frame 11, a cab 12 (driver's cab), a hoisting cylinder 13, a boom 14, a hook 15, a bracket 16, a telescopic boom 30, a counterweight CW, and a lifting device (winch, not shown).

[0052] The slewing frame 11 is supported by the lower traveling body 20 in a rotatable manner through a slewing bearing (not shown). The cab 12, the hoisting cylinder 13, the bracket 16, the telescopic boom 30, the counterweight CW, and a lifting device (not shown) are installed on the slewing frame 11.

[0053] The cab 12 is disposed, for example, at the front of the slewing frame 11. In the cab 12, in addition to a seat for an operator and various measuring instruments, an operation unit, a display unit, and a sound output unit used during crane operation and traveling are also disposed.

[0054] The hoisting cylinder 13 is installed between the slewing frame 11 and the telescopic boom 30. By the extension and contraction of the hoisting cylinder 13, the telescopic boom 30 rises and falls within a specified hoisting angle range (for example, 0° to 84°).

[0055] In the case of increasing the lifting height, the boom 14 is rotatably installed at the front end (arm head) of the telescopic boom 30. By rotating forward, the boom 14 can protrude forward of the telescopic boom 30.

[0056] The hook 15 is a lifting tool with a hook shape, having a main hook and an auxiliary hook. The hook 15 is installed on the steel cable 19, which is wound around a pulley at the front end of the telescopic boom 30 or the front end of the jib 14. The hook 15 moves up and down as the lifting device (not shown) lifts or pays out the steel cable 19.

[0057] The counterweight CW is installed at the rear of the slewing frame 11. The counterweight CW has a plurality of unit weights and can be set in such a way that different weights can be obtained by combining the unit weights.

[0058] The telescopic boom 30 is rotatably installed on the bracket 16 by a support shaft (foot pin, reference numeral omitted). The telescopic boom 30 has a plurality of boom elements including a front boom 31, an intermediate boom 32, and a base boom 33, and these boom elements are arranged in a nested and overlapping configuration (so-called "telescopic structure"). By the telescopic actuator 40 arranged inside (refer to Figure 5 ), the telescopic boom 30 is telescoped. The front boom 31 and the intermediate boom 32 among the plurality of boom elements slide and telescope in the telescopic direction with respect to the base boom 33. On the other hand, the base boom 33 cannot move in the telescopic direction. By sequentially extending from the boom element arranged inside (that is, the front boom 31), the telescopic boom 30 changes its state from the Figure 1 shown retracted state to the Figure 2 shown extended state.

[0059] In addition, a boom head (reference numeral omitted) having a pulley (reference numeral omitted) is arranged at the front end of the front boom 31. In addition, sometimes an operation attachment such as a skip is installed on the boom head. Further, in the telescopic boom 30, the number of segments of the intermediate boom 32 is not particularly limited.

[0060] The lower traveling body 20 includes a vehicle body frame 21, wheels 22, 23, outrigger legs OR1, OR2, and an engine (not shown), etc.

[0061] The driving force of the engine is transmitted to the wheels 22, 23 through a transmission mechanism (not shown). The wheels 22, 23 rotate by the driving force of the engine, so that the mobile crane 1 travels. In addition, the steering angle (traveling direction) of the wheels 22, 23 changes along with the operation of a steering wheel (not shown) provided in the cab 12.

[0062] During traveling, the outrigger legs OR1, OR2 are stored in the vehicle body frame 21. On the other hand, during operation (when the upper slewing body 10 operates), the outrigger legs OR1, OR2 project in the horizontal and vertical directions to lift and support the entire vehicle body and make the attitude stable.

[0063] Thus, the mobile crane 1 is a self-propelled crane that uses wheels 22 and 23 for the traveling section of the lower traveling body 20, and can perform traveling operations and crane operations in one cab.

[0064] In addition, as the mobile crane 1, in addition to rough terrain cranes, for example, all terrain cranes, truck cranes, or loading type truck cranes (also referred to as "ship cargo cranes") can be cited.

[0065] <Telescopic boom>

[0066] Figures 3A - 3C And Figures 4A - 4C are schematic diagrams for explaining the structure and extension operation of the telescopic boom 30. Figures 3A - 3C And Figures 4A - 4C is a longitudinal section along the width direction of the telescopic boom 30. The right side in the figure is the base end side of the telescopic boom 30, and the left side in the figure is the front end side of the telescopic boom 30. Here, for simplicity of explanation, the telescopic boom 30 in which the intermediate boom 32 is composed of one section is illustrated.

[0067] As Figures 3A - 3C And Figures 4A - 4C shown, the telescopic boom 30 has substantially the same structure as a conventionally known telescopic boom. The telescopic boom 30 has, for example, a structure that is symmetric in the width direction of the telescopic shaft. A telescopic device A for telescoping the telescopic boom 30 is disposed inside the telescopic boom 30.

[0068] In the telescopic boom 30, the front boom 31 and the intermediate boom 32 are connected by an arm connection pin (hereinafter referred to as "pin B") 315 provided on the front boom 31, and the intermediate boom 32 and the base boom 33 are connected by a pin B 325 provided on the intermediate boom 32. In addition, the front boom 31, the intermediate boom 32, and the base boom 33 are each connected to a telescopic actuator 40 by a cylinder connection pin (hereinafter referred to as "pin C") 150. The front boom 31 or the intermediate boom 32 connected to the telescopic actuator 40 by the pin C 150 becomes an arm element to be telescoped.

[0069] The front boom 31 has a cylindrical shape and has an internal space capable of accommodating the telescopic device A. The base end portion of the front boom 31 has a pin C receiving portion 311, a pin B holding portion 314, and a pin B 315.

[0070] A pair of pin C receiving portions 311 are configured to be able to engage and disengage with the pin C 150 (first fixing pin) provided on the pin insertion / removal actuator 50, respectively. The pin C receiving portions 311 are, for example, coaxially arranged with each other.

[0071] On the proximal end side of the C pin receiving portion 311, the B pin holding portion 314 is fixed to the frame of the front end arm 31 and holds the B pin 315 (second fixing pin) in a manner that allows for advancement and retraction. A pair of B pins 315 are arranged coaxially in the B pin holding portion 314, for example, and are urged in opposite directions toward the outer intermediate arms 32 by the urging force of the urging member. That is, when the front end arm 31 is not telescoping normally, the B pin 315 is inserted through the proximal end side B pin receiving portion 322 or the front end side B pin receiving portion 323 of the intermediate arm 32 and maintained in that state by the urging force of the urging member.

[0072] The intermediate arm 32 has a cylindrical shape and has an internal space capable of accommodating the front end arm 31. The proximal end portion of the intermediate arm 32 has a C pin receiving portion 321, a proximal end side B pin receiving portion 322, and a B pin holding portion 324, and the front end portion of the intermediate arm 32 has a front end side B pin receiving portion 323.

[0073] A pair of C pin receiving portions 321 are configured to be able to engage and disengage with the C pin 150 (first fixing pin) respectively. The C pin receiving portions 321 are arranged coaxially with each other, for example.

[0074] A pair of proximal end side B pin receiving portions 322 are provided on the proximal end side of the C pin receiving portion 321 and are arranged coaxially with each other. A pair of front end side B pin receiving portions 323 are provided at the front end portion of the intermediate arm 32 and are arranged coaxially with each other. The proximal end side B pin receiving portion 322 and the front end side B pin receiving portion 323 are configured to be able to insert and remove the B pin 315 of the front end arm 31 respectively.

[0075] On the side more proximal than the proximal end side B pin receiving portion 322, the B pin holding portion 324 is fixed to the frame of the intermediate arm 32 and holds the B pin 325 (second fixing pin) in a manner that allows for advancement and retraction. A pair of B pins 325 are arranged coaxially in the pin holding portion 324, for example, and are urged in opposite directions toward the outer proximal end arms 33 by the urging force of the urging member. That is, when the intermediate arm 32 is not telescoping normally, the B pin 325 is inserted through the proximal end side B pin receiving portion 332 or the front end side B pin receiving portion 333 of the proximal end arm 33 and maintained in that state by the urging force of the urging member.

[0076] The proximal end arm 33 has a cylindrical shape and has an internal space capable of accommodating the intermediate arm 32. The proximal end portion of the proximal end arm 33 has a proximal end side B pin receiving portion 332, and the front end portion of the proximal end arm 33 has a front end side B pin receiving portion 333.

[0077] A pair of proximal end side B pin receiving portions 332 are arranged coaxially with each other. A pair of front end side B pin receiving portions 333 are provided at the front end portion of the proximal end arm 33 and are arranged coaxially with each other. The proximal end side B pin receiving portion 332 and the front end side B pin receiving portion 333 are configured to be able to insert and remove the B pin 325 of the intermediate arm 32 respectively.

[0078] Based on the operation of the arm connection module 200 included in the pin insertion / removal actuator 50, the B pins 315 and 325 are displaced in their axial directions.

[0079] Specifically, the B pin 315 straddles and is inserted through the base-end side B-pin receiving portion 322 or the front-end side B-pin receiving portion 323 of the intermediate arm 32. Accordingly, the front-end arm 31 and the intermediate arm 32 are connected and become a connected state. On the other hand, if the B pin 315 is removed from the base-end side B-pin receiving portion 322 or the front-end side B-pin receiving portion 323 of the intermediate arm 32, the connection between the front-end arm 31 and the intermediate arm 32 is released and becomes a non-connected state.

[0080] The B pin 325 straddles and is inserted through the base-end side B-pin receiving portion 332 or the front-end side B-pin receiving portion 333 of the base-end arm 33. Accordingly, the intermediate arm 32 and the base-end arm 33 are connected and become a connected state. On the other hand, if the B pin 325 is removed from the base-end side B-pin receiving portion 332 or the front-end side B-pin receiving portion 333 of the base-end arm 33, the connection between the intermediate arm 32 and the base-end arm 33 is released and becomes a non-connected state.

[0081] In the connected state where the front-end arm 31 is connected to the intermediate arm 32 through the B pin 315, the front-end arm 31 cannot move in the telescopic direction relative to the intermediate arm 32. In the non-connected state, the front-end arm 31 can move in the telescopic direction relative to the intermediate arm 32. Similarly, in the connected state where the intermediate arm 32 is connected to the base-end arm 33 through the B pin 325, the intermediate arm 32 cannot move in the telescopic direction relative to the base-end arm 33. In the non-connected state, the intermediate arm 32 can move in the telescopic direction relative to the base-end arm 33.

[0082] Based on the operation of the oil cylinder connection module 100 included in the pin insertion / removal actuator 50, the C pin 150 is displaced in its axial direction.

[0083] Specifically, the front-end arm 31 and the intermediate arm 32 obtain either a engaged state where the C pin 150 is engaged with the C-pin receiving portions 311 and 321, or a non-engaged state where the C pin 150 is disengaged from the C-pin receiving portions 311 and 321. In the engaged state, the front-end arm 31 and the intermediate arm 32 can move in the telescopic direction together with the movable portion (in this embodiment, the oil cylinder portion 42) of the telescopic actuator 40. When the intermediate arm 32 moves, the front-end arm 31 connected to the intermediate arm 32 through the B pin 315 also moves in the telescopic direction.

[0084] Hereinafter, the extension operation of the telescopic arm 30 will be briefly described.

[0085] Figure 3A Shows the fully retracted state of the telescopic arm 30. In this state, the front-end arm 31 is housed in the intermediate arm 32, is connected to the intermediate arm 32 through the B pin 315, and cannot move in the extension direction (refer to Figure 3C) Move upward. Additionally, the C pin 150 engages with the C-pin receiving portion 311 of the front end arm 31, and the front end arm 31 and the oil cylinder portion 42 are in an engaged state.

[0086] As Figure 3B shown, the B pin 315 is pulled out from the B-pin receiving portion 322 on the base end side of the intermediate arm 32 (refer to the part enclosed by the dashed line in Figure 3B ), and the front end arm 31 and the intermediate arm 32 are in a non-connected state, and the front end arm 31 can move in the extending direction.

[0087] As Figure 3C shown, as the telescopic actuator 40 operates and the oil cylinder portion 42 moves in the extending direction, the front end arm 31 moves toward the front end side.

[0088] As Figure 4A shown, after the front end arm 31 moves to a specified position, the B pin 315 is inserted through the front end side B-pin receiving portion 323 of the intermediate arm 32 (refer to the part enclosed by the dashed line in Figure 4A ), and the front end arm 31 and the intermediate arm 32 are in a connected state, and the front end arm 31 cannot move in the extending direction.

[0089] As Figure 4B shown, the engagement between the C-pin receiving portion 311 of the front end arm 31 and the C pin 150 is released (refer to the part enclosed by the dashed line in Figure 4B ), separated from the front end arm 31, and only the oil cylinder portion 42 can be reset to the contracted state.

[0090] And, as Figure 4C shown, the oil cylinder portion 42 is reset to the contracted state, the C-pin receiving portion 321 of the intermediate arm 32 engages with the C pin 150, and the intermediate arm 32 and the oil cylinder portion 42 are in an engaged state.

[0091] In addition, when extending the intermediate arm 32, the same operation as above is performed. Additionally, when contracting the front end arm 31 or the intermediate arm 32, the operation in the opposite direction to the above is performed.

[0092] <Telescopic device>

[0093] The above-described extending and contracting operations of the telescopic arm 30 are performed by a telescopic device A built in the telescopic arm 30. In the fully contracted state of the telescopic arm 30 (the state shown in Figure 3A ), the telescopic device A is arranged in the internal space of the front end arm 31. Hereinafter, the detailed structure of the telescopic device A will be described.

[0094] Figure 5It is a perspective view of the appearance of the telescopic device A. Hereinafter, regarding each structural element constituting the telescopic device A, with the state where it is assembled to the telescopic device A as a reference, it will be described using an orthogonal coordinate system (X, Y, Z). The same orthogonal coordinate system (X, Y, Z) is also used in the figures described later. In the orthogonal coordinate system (X, Y, Z), the X direction is the same as the telescopic direction of the telescopic arm 30. The X direction + side is the front end side of the telescopic arm 30, and the X direction - side is the base end side of the telescopic arm 30. In the collapsed state where the undulation angle of the telescopic arm 30 is 0°, the Z direction is, for example, the same as the up and down direction of the mobile crane 1. The Y direction is orthogonal to the X direction and the Z direction, and is, for example, the same as the width direction of the telescopic arm 30.

[0095] As Figure 5 shown, the telescopic device A includes a telescopic actuator 40 and a pin insertion / removal actuator 50. The pin insertion / removal actuator 50 is arranged, for example, on the base end side of the telescopic actuator 40 so as to be able to move together with the oil cylinder part 42.

[0096] The telescopic actuator 40 is a hydraulic cylinder having a piston rod part 41 (refer to Figure 3A etc.) and an oil cylinder part 42. The telescopic actuator 40 moves an arm element (such as the front end arm 31 or the intermediate arm 32) connected to the oil cylinder part 42 through a C pin 150 (refer to Figure 3A etc.) in the telescopic direction. The oil cylinder part 42 has, for example, an oil cylinder frame 43 with a guide rail. The guide rail (not shown) of the oil cylinder frame 43 engages with the guide rail groove provided on the telescopic arm 30. Accordingly, the oil cylinder part 42 can slide along the telescopic arm 30 in the telescopic direction in a stable posture. In addition, since the main structure of the telescopic actuator 40 is substantially the same as that of a known hydraulic cylinder, a detailed description thereof is omitted.

[0097] Figures 6 - 10 Shows the structure of the pin insertion / removal actuator 50. Figures 6 - 8 Are respectively a perspective view of the pin insertion / removal actuator 50, a plan view obtained by observing from the Z direction + side, and a side view obtained by observing from the Y direction + side. Figure 9 、 Figure 10 Are respectively a perspective view of the state where the pin insertion / removal actuator 50 engages with the B pin holding part 314 and a front view obtained by observing from the X direction - side.

[0098] In Figures 6 - 10 ,in order to distinguish a pair of C pins 150, they are denoted as "C pins 150A, 150B". In addition, in Figure 9 、 Figure 10 ,in order to distinguish a pair of B pins 315, they are denoted as "B pins 315A, 315B".

[0099] As Figures 6 - 8As shown, the actuator 50 for pin insertion / extraction is disposed on the X-direction side (base end side) of the oil cylinder unit 42 and moves in the telescopic direction together with the oil cylinder unit 42. The actuator 50 for pin insertion / extraction includes an electric motor 51 (electrical drive source), a brake 52, a transmission mechanism 53, a position detection device 54, a locking mechanism 55 (refer to Figure 11 etc.), an oil cylinder connection module 100 (first connection device), and an arm connection module 200 (second connection device). The transmission mechanism 53 includes a clutch 61, a speed reducer 62, and a torque limiter 63 (refer to Figure 14 ).

[0100] Each structural element is disposed within the housing 58 and unitized. Accordingly, it is possible to miniaturize the actuator 50 for pin insertion / extraction, improve productivity, and improve the reliability of the system. Specifically, the housing 58 has a box-shaped first housing 581 and a box-shaped second housing 582.

[0101] The internal space of the first housing 581 houses the oil cylinder connection module 100. The C pins 150A and 150B of the oil cylinder connection module 100 are arranged so that they can advance and retreat from the two ends in the Y direction of the first housing 581, respectively. In the first housing 581, the piston rod portion 41 of the telescopic actuator 40 is inserted through in the X direction (refer to Figure 3A etc.). The end portion of the oil cylinder unit 42 is fixed to the side wall on the +X direction side of the first housing 581.

[0102] The second housing 582 is disposed on the +Z direction side of the first housing 581. The internal space of the second housing 582 houses the arm connection module 200. The rack bars 220A for the B pins of the arm connection module 200 are arranged so that they can advance and retreat from one end in the Y direction of the second housing 582, respectively, and the rack bars 220B for the B pins are arranged so that they can advance and retreat from the other end. In addition, the transmission shaft 56 of the transmission mechanism 53 is inserted through in the X direction in the second housing 582 (refer to Figure 12 ).

[0103] The electric motor 51 is an electrical drive source for operating the oil cylinder connection module 100 and the arm connection module 200. The electric motor 51 is configured as a rotary motor that outputs a rotary motion using electromagnetic force, for example. As the rotary motor, various electromagnetic motors such as a brushed motor (DC motor), a brushless DC motor, and a stepping motor can be applied, for example. The operation of the electric motor 51 is controlled by a control device 70 (refer to Figure 14 ).

[0104] The electric motor 51 is supported by the second housing 582 through the transmission mechanism 53. The output shaft (not shown) of the electric motor 51 extends in the X direction. The electric motor 51 is configured such that, for example, a gear ring (not shown) arranged on the outer periphery of the piston rod portion 41 as a mechanical element of the transmission mechanism 53 meshes with the output shaft of the electric motor 51. By arranging the electric motor 51 in this way, miniaturization of the pin insertion / removal actuator 50 can be achieved in the Y direction and the Z direction.

[0105] The electric motor 51 can also be arranged in the cylinder frame 43 by using a flat motor such as a large-sized thin motor or a planar opposed type motor. In this case, the structure can be made compact, and the cylinder frame 43 can function as a protective cover, reducing the risk of breakage caused by interference during the arm telescoping operation. In addition, by making use of the large outer diameter of the motor and directly transmitting power from the output shaft of the electric motor 51 to the large-diameter gear ring, the reduction ratio can be reduced, and the inertia of the C-pin biasing mechanism 160 or the B-pin biasing mechanism 240 during the insertion operation can also be reduced.

[0106] The electric motor 51 is connected, for example, to a power supply device (not shown) arranged on the upper rotating body 10 (refer to Figure 1 ) through a power supply cable. In addition, the electric motor 51 is connected, for example, to a control device 70 arranged on the upper rotating body 10 through a control signal transmission cable. These cables can be wound out and wound up through a cable reel arranged at the base end portion of the telescopic arm 30 or the upper rotating body 10 (refer to Figure 1 ).

[0107] The power supply cable and the control signal transmission cable have a small wiring space and can be freely wound, so the degree of freedom in the design around the telescopic arm 30 is significantly improved compared with the case of arranging hydraulic actuators and hydraulic circuits.

[0108] In addition, the electric motor 51 has a manual operation portion 511 that can be operated by a manual handle (not shown). The manual operation portion 511 is an operation portion for manually performing the state transition of the pin insertion / removal actuator 50 (specifically, the cylinder connection module 100 and the arm connection module 200). In the event of a motor failure or the like, by rotating the manual operation portion 511 with the manual handle, the output shaft of the electric motor 51 rotates to transfer the state of the pin insertion / removal actuator 50, enabling the B-pins 315, 325 and the C-pin 150 to be inserted and removed.

[0109] In this embodiment, an oil cylinder connection module 100 and an arm connection module 200 are actuated by one electric motor 51. Additionally, a motor for the oil cylinder connection module 100 and a motor for the arm connection module 200 can be separately provided as the electric motor 51. For example, when the output shaft of the electric motor 51 is connected to the ring gear (not shown) of the transmission mechanism 53, the arrangement of the electric motor 51 is not limited as long as it is on the outer circumference of the ring gear. Therefore, it is possible to easily arrange multiple small motors as the electric motor 51. In addition, the required torque can be obtained by increasing or decreasing the number of electric motors 51. Thus, it can be achieved with one type of motor and can also be easily applied to the designs of other models.

[0110] The brake 52 applies a braking force to the electric motor 51. The brake 52 is configured as, for example, an electromagnetic brake that uses electromagnetic force for braking. The operation of the brake 52 is controlled by the control device 70.

[0111] In the stopped state (non-energized state) of the electric motor 51, the brake 52 restricts the rotation of the output shaft of the electric motor 51. The brake 52 operates, for example, in the retracted state of the oil cylinder connection module 100 or the retracted state of the arm connection module 200. Accordingly, in the stopped state of the electric motor 51, the retracted states of the oil cylinder connection module 100 and the arm connection module 200 are maintained. Compared with the case of maintaining the retracted state by the motor torque, power consumption can be reduced, and in addition, it is possible to prevent the electric motor 51 from overheating due to being in a locked state.

[0112] Furthermore, if an external force of a specified magnitude acts on the oil cylinder connection module 100 or the arm connection module 200 during braking, the brake 52 may also allow the rotation (i.e., slipping) of the electric motor 51. Accordingly, it is possible to prevent mechanical elements (such as the electric motor 51 and various gears) of the pin insertion / removal actuator 50 from being damaged due to overload.

[0113] The brake 52 is arranged at a stage more upstream than the speed reducer 62 of the transmission mechanism 53. The upstream stage refers to the upstream side (X-direction - side) in the power transmission path where the power of the electric motor 51 is transmitted to the oil cylinder connection module 100 or the arm connection module 200, including the upstream side of the electric motor 51. On the other hand, the downstream stage refers to the downstream side (X-direction + side) in the power transmission path of the electric motor 51. In the present embodiment, the brake 52 is coaxially arranged with the electric motor 51 on the X-direction - side (i.e., the opposite side of the transmission mechanism 53 centered on the electric motor 51). By arranging the brake 52 in this way, miniaturization of the pin insertion / extraction actuator 50 can be achieved in the Y direction and the Z direction. In addition, when the brake 52 is arranged at a stage more upstream than the speed reducer 62 compared to the case where it is arranged at a stage more downstream than the speed reducer 62, the brake torque required to maintain the stopped state of the electric motor 51 becomes smaller, so miniaturization of the brake 52 can be achieved.

[0114] In addition, various brake devices such as mechanical or electromagnetic types can be applied to the brake 52. In addition, the position of the brake 52 is not limited to the position in the present embodiment.

[0115] The transmission mechanism 53 transmits the power (i.e., rotational motion) of the electric motor 51 to the oil cylinder connection module 100 and the arm connection module 200. The transmission mechanism 53 is arranged in the second housing 582. The transmission mechanism 53 includes a clutch 61, a speed reducer 62, a torque limiter 63, etc. (refer to Figure 14 ). For example, the transmission mechanism 53 has a gear ring (not shown) arranged on the outer periphery of the piston rod portion 41 and a transmission gear meshing with the gear ring, and the clutch 61, the speed reducer 62, and the torque limiter 63 are arranged on the transmission shaft 56 connected to the transmission gear.

[0116] The clutch 61 is arranged in the power transmission path for transmitting the power of the electric motor 51 and transmits the power to the oil cylinder connection module 100 and the arm connection module 200 in a manner that can be freely disconnected and connected. In the power transmission path, the clutch 61 is arranged, for example, at the upstream stage of the speed reducer 62 (in the present embodiment, between the electric motor 51 and the speed reducer 62). By arranging the clutch 61 in this way, the transmission torque capacity of the clutch 61 can be reduced, and miniaturization of the clutch 61 can be achieved.

[0117] For example, an electromagnetic clutch, a mechanical clutch, or a torque diode can be applied to the clutch 61. These structures are well-known, so they will be briefly described.

[0118] An electromagnetic clutch is a mechanical element that cuts off or transmits power from the input shaft to the output shaft in an electromagnetic manner. When an electromagnetic clutch is applicable, the operation of the clutch 61 is controlled by a control device 70, for example. In addition, when the operation of the clutch 61 is interlocked with the electric motor 51, there is no need to separately control the clutch 61.

[0119] A mechanical clutch is a mechanical element that transmits power by meshing the input shaft and the output shaft with each other. When a mechanical clutch is applicable, the clutch 61 is preferably a one-way clutch that transmits power from the input shaft to the output shaft on the one hand and cuts off the power from the output shaft to the input shaft on the other hand, transmitting power only in one direction.

[0120] A torque one-way member is a mechanical element that transmits power from the input shaft to the output shaft on the one hand and cuts off the power from the output shaft to the input shaft on the other hand.

[0121] When a mechanical clutch and a torque one-way member are applicable, there is no need for electrical control by the control device 70 or the like.

[0122] The speed reducer 62 reduces the rotation of the electric motor 51 and outputs it. The speed reducer 62 is constituted by a planetary gear mechanism housed in a speed reducer case (reference numeral omitted), and the input shaft and the output shaft extend in the X direction. By arranging the speed reducer 62 in this way, miniaturization of the pin insertion / removal actuator 50 can be achieved in the Y direction and the Z direction.

[0123] The torque limiter 63 is an overload protection device that is arranged in the power transmission path for transmitting the power of the electric motor 51 and keeps the torque acting on the mechanical elements (for example, the electric motor 51) constituting the power transmission path below a specified value. For example, in the power transmission path, the torque limiter 63 is arranged at the subsequent stage of the speed reducer 62. By arranging the torque limiter 63 in this way, the influence of the tolerance and deviation of the torque setting value can be reduced compared with the case where it is arranged at the previous stage of the speed reducer 62. In addition, for example, in the power transmission path, the torque limiter 63 may also be arranged at the previous stage of the speed reducer 62. In this case, since the torque setting value becomes smaller, miniaturization of the torque limiter 63 can be achieved.

[0124] In addition, by continuously driving the electric motor 51, the torque limiter 63 continuously slides, and a specified torque can be continuously provided to the oil cylinder connection module 100 and the arm connection module 200. Therefore, the torque limiter 63 can be used as an alternative to the brake 52 to maintain the extended state of the oil cylinder connection module 100 and the arm connection module 200. In addition, since the electric motor 51 is not in a locked state, it does not heat up due to overload.

[0125] The torque limiter 63 is constituted by, for example, a friction torque limiter, which is installed on the output shaft of the clutch 61 (transmission shaft 56 of the transmission mechanism 53), and in the case where a torque greater than a specified value is generated, the input-side element and the output-side element are joined in such a way as to cause slippage.

[0126] The position detection device 54 detects the displacements of the C pin 150 and the B pins 315, 325 based on the output of the electric motor 51 (for example, the rotation of the output shaft). The position detection device 54 detects, for example, the moving direction (rotation direction) and the moving amount (rotation angle) of the C pin 150 or the B pins 315, 325 from a reference position (refer to Figure 17A and Figure 18A ).

[0127] The position detection device 54 is constituted by, for example, an angle sensor such as a rotary encoder or a potentiometer, and outputs information (for example, a pulse signal, a code signal) corresponding to the rotation amount of the output shaft of the electric motor 51. The rotary encoder detects and outputs the rotational displacement of the input shaft using an internal code wheel. The potentiometer converts the change in the rotation angle into a change in the resistance value and outputs it.

[0128] The output method of the rotary encoder is not particularly limited, and it can be either an incremental method of outputting a pulse signal (relative angle signal) corresponding to the rotation amount (rotation angle) from the measurement start position, or an absolute method of outputting a code signal (absolute angle signal) corresponding to the absolute angular position with respect to a reference point.

[0129] In the case where the position detection device 54 is constituted by a rotary encoder in the absolute method, even when reset from the non-powered state to the powered state, the absolute positions of the C pin 150 and the B pins 315, 325 can be detected.

[0130] The position detection device 54 can be directly provided on the output shaft of the electric motor 51, or can be provided on a rotating member (such as a rotating shaft, a gear, etc.) that rotates together with the output shaft of the electric motor 51.

[0131] In the present embodiment, the position detection device 54 is provided on the transmission shaft 56 at the subsequent stage (X direction + side) of the transmission mechanism 53 (torque limiter 63), and outputs information corresponding to the rotation amount of the transmission shaft 56. In this case, the position detection device 54 preferably uses a rotary encoder that can obtain sufficient resolution for the rotational speed (rotation speed) of the transmission shaft 56.

[0132] In addition, since the C-pin missing-tooth gear 110 of the oil cylinder connection module 100 and the B-pin missing-tooth gear 210 of the arm connection module 200 are fixed on the transmission shaft 56, it can also be said that the detection result of the position detection device 54 is information corresponding to the rotation amounts of the C-pin missing-tooth gear 110 and the B-pin missing-tooth gear 210.

[0133] In addition, the position detection device 54 is not limited to the above-mentioned rotary encoder. For example, it can also be constituted by a limit switch or a proximity sensor. The limit switch is arranged at a stage further downstream than the speed reducer 62 and mechanically operates based on the output of the electric motor 51. In addition, the proximity sensor is arranged at a stage further downstream than the speed reducer 62, opposite to a rotating member that rotates based on the output of the electric motor 51, and outputs a detection signal based on the distance from the above-mentioned rotating member. The detection result of the position detection device 54 is output to the control device 70.

[0134] However, for the proximity sensor and the limit switch, for example, they are arranged at positions where the insertion state and the extraction state of the C-pin 150 and the B-pins 315 and 325 can be detected, and the number is at least the same as that of the C-pin 150 and the rack bars 220A and 220B for the B-pins. In contrast, in the case of applying a rotary encoder, the states of the C-pin 150 and the B-pins 315 and 325 can be detected by one detection sensor, so the number of components can be reduced and low cost can be achieved.

[0135] In addition, the arrangement of the position detection device 54 is not limited to this embodiment. For example, the position detection device 54 can also be arranged at a stage further upstream than the speed reducer 62. That is, the position detection device 54 can also obtain information output to the control device 70 based on the rotation of the electric motor 51 before being decelerated by the speed reducer 62. Comparing the arrangement of the position detection device 54 at the upstream stage of the speed reducer 62 with that at the downstream stage of the speed reducer 62, a higher resolution can be obtained.

[0136] The control device 70 is, for example, an in-vehicle computer, which has a CPU (Central Processing Unit, central processing unit) as an arithmetic / control device, a ROM (Read Only Memory, read-only memory) and a RAM (Random Access Memory, random access memory) as main storage devices, input terminals, output terminals, etc. The control device 70 calculates information related to the position of the C-pin 150 or the B-pins 315 and 325 based on the output of the position detection device 54. In the calculation, data (table, map, etc.) representing the correlation between the output of the position detection device 54 and the information related to the positions of the C-pin 150 and the B-pins 315 and 325 (for example, the amount of movement from the reference position) is used. This data is stored in the ROM, for example.

[0137] The control device 70, for example, judges whether the C-pin 150 and the C-pin receiving parts 311 and 321 of the front end arm 31 or the middle arm 32 are in an engaged state (for example, Figure 3A the state shown) or in a non-engaged state (for example, Figure 4BThe state shown), that is, the connection state of the pin insertion / removal actuator 50 to the front end arm 31 or the intermediate arm 32 is judged.

[0138] In addition, when the telescoping object is the front end arm 31, the control device 70 judges whether the B pin 315 of the front end arm 31 and the intermediate arm 32 are in the engaged state (refer to Figure 3A , Figure 3C etc.) or in the non-engaged state (refer to Figure 3B ) through arithmetic operation based on the detection result of the position detection device 54, that is, the connection state of the front end arm 31 and the intermediate arm 32 is judged. Similarly, when the telescoping object is the intermediate arm 32, the control device 70 judges the connection state of the intermediate arm 32 and the base end arm 33 through arithmetic operation based on the detection result of the position detection device 54.

[0139] Based on the arithmetic result, the control device 70 executes various controls of the pin insertion / removal actuator 50 including the operation control of, for example, the electric motor 51, the brake 52, the clutch 61, etc. In addition, when executing various controls of the pin insertion / removal actuator 50, information indicating the state of the telescoping arm 30 or the telescoping actuator 40 can be obtained by using various sensors provided on the telescoping arm 30 and the telescoping actuator 40, for example.

[0140] Refer to Figures 11 - 14 , and the oil cylinder connection module 100 and the arm connection module 200 will be described. Figures 11 - 13 is a diagram showing the internal structure of the pin insertion / removal actuator 50. Figure 14 is a diagram schematically showing the structure of the pin insertion / removal actuator 50.

[0141] Figures 11 - 14 represents the neutral state. In this neutral state, the electric motor 51 is in the stopped state, and the oil cylinder connection module 100 and the arm connection module 200 are not operating. In the neutral state, the oil cylinder connection module 100 and the arm connection module 200 together become the inserted state. For example, the movement of the C-pin rack bar 120 and the B-pin rack bars 220A, 220B is mechanically restricted by a stopper (not shown) to maintain the neutral state. In addition, it can also be configured to maintain the neutral state by the balance of the biasing force of the C-pin biasing mechanism 160 and the biasing force of the B-pin biasing mechanism 240.

[0142] In addition, Figure 15A , Figure 15B represents the retracted state of the arm connection module 200 and the retracted state of the oil cylinder connection module 100. As Figure 15A shown, in the retracted state of the oil cylinder connection module 100, the arm connection module 200 is held in the inserted state. As Figure 15B shown, in the retracted state of the arm connection module 200, the oil cylinder connection module 100 is held in the inserted state.

[0143] The oil cylinder connection module 100 operates based on the power (i.e., rotational motion) of the electric motor 51 and transfers states between the inserted state (refer to Figure 11 ) and the withdrawn state (refer to Figure 15A ).

[0144] The inserted state of the oil cylinder connection module 100 refers to the state where the C-pin receiving parts 311 and 321 of the front end arm 31 or the intermediate arm 32 are engaged with the C-pin 150, connecting the respective arm elements to the pin insertion / removal actuator 50. In this connected state, the front end arm 31 and the intermediate arm 32 can move together with the oil cylinder part 42 and the pin connection actuator 50 (refer to Figure 3B , Figure 15B etc.).

[0145] On the other hand, the withdrawn state of the oil cylinder connection module 100 refers to the state where the C-pin 150 is disengaged from the C-pin receiving parts 311 and 321 of the front end arm 31 or the intermediate arm 32, separating the respective arm elements from the pin connection actuator 50. In this unconnected state, the oil cylinder part 42 and the pin connection actuator 50 can move independently from their respective arm elements (refer to Figure 4B , Figure 15A etc.).

[0146] The arm connection module 200 operates based on the power (i.e., rotational motion) of the electric motor 51 and transfers states between the inserted state (refer to Figure 11 ) and the withdrawn state (refer to Figure 15B ).

[0147] The inserted state of the arm connection module 200 refers to the state where, for example, the B-pin 315 is inserted through the base-end side B-pin receiving part 322 or the front-end side B-pin receiving part 323 of the intermediate arm 32 to connect the front end arm 31 and the intermediate arm 32. In this connected state, in the telescopic direction, the front end arm 31 cannot move relative to the intermediate arm 32 (refer to Figure 3A , Figure 15A etc.).

[0148] On the other hand, the withdrawn state of the arm connection module 200 refers to the state where, for example, the B-pin 315 is disengaged from the base-end side B-pin receiving part 322 or the front-end side B-pin receiving part 323 of the intermediate arm 32 to separate the front end arm 31 and the intermediate arm 32. In this unconnected state, in the telescopic direction, the front end arm 31 can move relative to the intermediate arm 32 (refer to Figure 3B , Figure 15B etc.).

[0149] As Figures 11 - 14As shown, the oil cylinder connection module 100 has a C-pin idler gear 110, a C-pin rack bar 120, a first gear set 130, a second gear set 140, a C-pin 150, and a C-pin biasing mechanism 160. Each mechanical element 110-160 is an example of a structural component of the first connection mechanism. In the following description, to distinguish the C-pin 150, it is denoted as "C-pins 150A, 150B".

[0150] In addition, in the present embodiment, a pair of C-pins 150A, 150B are assembled in the oil cylinder connection module 100, but the C-pins 150A, 150B may also be provided independently of the oil cylinder connection module 100.

[0151] The C-pin idler gear 110 is a gear in the shape of a substantially circular wheel plate, and a part of the outer peripheral surface of the C-pin idler gear 110 has a tooth portion 111 (see Figure 12 ). The C-pin idler gear 110 is externally fitted and fixed to the transmission shaft 56 of the transmission mechanism 53 and rotates together with the transmission shaft 56. The C-pin idler gear 110 and the B-pin idler gear 210 of the arm connection module 200 together form a switching gear G (see Figure 14 ). The power of the electric motor 51 is selectively transmitted to either the oil cylinder connection module 100 or the arm connection module 200 through the switching gear G.

[0152] In the present embodiment, the C-pin idler gear 110 and the B-pin idler gear 210 that form the switching gear G are respectively assembled into the oil cylinder connection module 100 as the first connection mechanism and the arm connection module 200 as the second connection mechanism, but the switching gear G may also be provided independently of the first connection mechanism and the second connection mechanism.

[0153] In addition, the switching gear G can perform the functions of the C-pin idler gear 110 and the B-pin idler gear 210. For example, as Figure 14 shown, it may also be composed of one idler gear.

[0154] In the following description, when the oil cylinder connection module 100 transfers from the inserted state (see Figure 11 ) to the withdrawn state (see Figure 15A ), the rotation direction of the C-pin idler gear 110 (the R1 direction in Figure 14 ) is referred to as "forward", and when transferring from the withdrawn state to the inserted state, the rotation direction of the C-pin idler gear 110 (the R2 direction in Figure 14 ) is referred to as "reverse".

[0155] Among the convex portions that make up the tooth portion 111 of the C-pin idler gear 110, the convex portion provided at the forward end of the C-pin idler gear 110 is a positioning tooth (not shown).

[0156] The rack bar 120 for the C pin is, for example, a shaft member that extends unidirectionally and is arranged in the Y direction on the lower side (Z direction - side) of the toothless gear 110 for the C pin.

[0157] The surface of the rack bar 120 for the C pin on the side closer to the toothless gear 110 for the C pin (Z direction + side) has an input-side rack portion 121, and the surface of the rack bar 120C for the C pin on the side farther from the toothless gear 110 for the C pin (Z direction - side) has two output-side rack portions 122 and 123.

[0158] Only when the cylinder connection module 100 makes a state transition from the inserted state (refer to Figure 11 ) to the withdrawn state (refer to Figure 15A ), the input-side rack portion 121 meshes with the tooth portion 111 of the toothless gear 110 for the C pin.

[0159] Specifically, in the inserted state of the cylinder connection module 100, the first end surface (not shown) on the Y direction + side of the input-side rack portion 121 abuts against the positioning tooth (not shown) in the tooth portion 111 of the toothless gear 110 for the C pin, or is opposed in the Y direction with a minute gap therebetween. In this state, if the toothless gear 110 for the C pin rotates in the R1 direction, the positioning tooth presses the first end surface toward the Y direction + side, and the rack bar 120 for the C pin moves toward the Y direction + side. Moreover, the tooth portions 111 formed in the reverse direction compared to the positioning tooth sequentially mesh with the input-side rack portion 121. Accordingly, as the toothless gear 110 for the C pin rotates in the R1 direction, the rack bar 120 for the C pin moves toward the Y direction + side.

[0160] In addition, when the toothless gear 110 for the C pin rotates in the R2 direction starting from the inserted state of the cylinder connection module 100 shown in Figure 11 , the input-side rack portion 121 does not mesh with the tooth portion 111 of the toothless gear 110 for the C pin.

[0161] In this way, as the toothless gear 110 for the C pin rotates, the rack bar 120 for the C pin moves in its own length direction (Y direction). The rack bar 120 for the C pin is located on the most Y direction - side (refer to Figure 11 ) in the inserted state of the cylinder connection module 100, and is located on the most Y direction + side (refer to Figure 15A ) in the withdrawn state.

[0162] That is, if the C-pin with an incomplete gear 110 rotates in the R1 direction in the inserted state (neutral state) of the oil cylinder connection module 100, the rack bar 120 for the C-pin moves in the + side of the Y direction and transfers to the withdrawn state. On the other hand, if the C-pin with an incomplete gear 110 rotates in the R2 direction in the withdrawn state of the oil cylinder connection module 100, the rack bar 120 for the C-pin moves in the - side of the Y direction and transfers to the inserted state.

[0163] The output-side rack portions 122 and 123 are respectively engaged with the first gear set 130 and the second gear set 140.

[0164] The first gear set 130 has, for example, a driving gear 131, an intermediate gear 132, and a driven gear 133. Each gear element is constituted by a spur gear.

[0165] Specifically, the driving gear 131 is engaged with the output-side rack portion 122 of the rack bar 120 for the C-pin and the intermediate gear 132. The intermediate gear 132 is engaged with the driving gear 131 and the driven gear 133. The driven gear 133 is engaged with the intermediate gear 132 and the pin-side rack portion 151 of one C-pin 150A.

[0166] When the oil cylinder connection module 100 is in the inserted state, the driving gear 131 is engaged with the end portion or a portion near the end portion on the + side in the Y direction of the output-side rack portion 122 of the rack bar 120 for the C-pin. In addition, the driven gear 133 is engaged with the end portion on the - side in the Y direction of the pin-side rack portion 151 of one C-pin 150A.

[0167] The second gear set 140 has, for example, a driving gear 141 and a driven gear 142. Each gear element is constituted by a spur gear.

[0168] Specifically, the driving gear 141 is engaged with the output-side rack portion 123 of the rack bar 120 for the C-pin and the driven gear 142. The driven gear 142 is engaged with the driving gear 141 and the pin-side rack portion 151 of the other C-pin 150B.

[0169] When the oil cylinder connection module 100 is in the inserted state, the driving gear 141 is engaged with the end portion or a portion near the end portion on the + side in the Y direction of the output-side rack portion 123 of the rack bar 120 for the C-pin. In addition, the driven gear 142 is engaged with the end portion on the + side in the Y direction of the pin-side rack portion 151 of the other C-pin 150B.

[0170] In the first gear set 130, the driving gear 131 and the driven gear 133 are connected by an intermediate gear 132. In contrast, in the second gear set 140, the driving gear 141 and the driven gear 142 are directly connected. Therefore, the rotation direction of the driven gear 133 in the first gear set 130 is opposite to the rotation direction of the driven gear 142 in the second gear set 140.

[0171] A pair of C pins 150A and 150B are arranged, for example, coaxially with each other in the Y direction. Preferably, the C pins 150A and 150B are symmetric about the center of the piston rod portion 41 of the telescopic actuator 40. Accordingly, it is possible to prevent the piston rod portion 41 from generating bending stress and to reduce the size in the height direction (Z direction).

[0172] In addition, the C pins 150A and 150B may be arranged symmetrically left and right in the telescopic direction (X direction). For example, they may also be arranged at positions offset from each other in the Z direction, or may be arranged at positions eccentric with respect to the piston rod portion 41 (for example, on the -Z direction side of the piston rod portion 41).

[0173] Hereinafter, the front end portions of the C pins 150A and 150B refer to the end portions on the side away from each other, and the base end portions refer to the end portions on the side close to each other.

[0174] The C pins 150A and 150B have pin-side rack portions 151 on their outer peripheral surfaces. The pin-side rack portion 151 of one C pin 150A meshes with the driven gear 133 of the first gear set 130. The pin-side rack portion 151 of the other C pin 150B meshes with the driven gear 142 of the second gear set 140.

[0175] The C pins 150A and 150B move in their own axial directions (Y direction) as the driven gears 133 and 142 rotate. Specifically, one C pin 150A moves to the -Y direction side when the cylinder connection module 100 transfers from the inserted state to the withdrawn state, and moves to the +Y direction side when transferring from the withdrawn state to the inserted state. The other C pin 150B moves to the +Y direction side when the cylinder connection module 100 transfers from the inserted state to the withdrawn state, and moves to the -Y direction side when transferring from the withdrawn state to the inserted state. That is, in the above state transfer, the C pins 150A and 150B move in opposite directions to each other in the Y direction.

[0176] The C-pin biasing mechanism 160 biases the C pins 150A and 150B in a direction away from each other. The C-pin biasing mechanism 160 is constituted by, for example, a pair of compression coil springs. In the present embodiment, the C-pin biasing mechanism 160 is arranged on the base end side of the C pins 150A and 150B and biases the C pins 150A and 150B toward the front end side.

[0177] If the electric motor 51 rotates in the R1 direction so that the oil cylinder connection module 100 is in the retracted state (refer to Figure 15A ), and the operation of the electric motor 51 stops, the oil cylinder connection module 100 automatically returns to the inserted state by the biasing force of the biasing mechanism 160 for the C pins. However, when the brake 52 is operating, the oil cylinder connection module 100 does not automatically return to the inserted state but remains in the retracted state.

[0178] In addition, the biasing mechanism 160 for the C pins can directly apply a biasing force to the C pins 150A and 150B, or can apply a biasing force through other components. Alternatively, the biasing mechanism 160 for the C pins can be omitted, and based on the power of the electric motor 51, the oil cylinder connection module 100 makes a state transition from the retracted state to the inserted state. Even in this case, from the viewpoint of fail-safe, it is preferably structurally provided with the biasing mechanism 160 for the C pins to return to the safe-side inserted state in case of motor failure.

[0179] As Figures 11 - 13 shown, the arm connection module 200 has a toothless gear 210 for the B pins, a pair of rack bars 220A and 220B for the B pins, a synchronizing gear 230 (refer to Figure 14 ), and a biasing mechanism 240 for the B pins. Each mechanical element 210 to 240 is an example of the structural components of the second connection mechanism. In the following description, for the purpose of distinguishing the B pin 315, it is denoted as "B pins 315A and 315B". In addition, the case where the arm connection module 200 acts on the B pin 315 is described, but the case where it acts on the B pin 325 is the same.

[0180] The toothless gear 210 for the B pins is a gear in the shape of a substantially circular disc, and has a tooth portion 211 on a part of its outer peripheral surface. The toothless gear 210 for the B pins is externally fitted and fixed to the transmission shaft 56 on the + side in the X direction closer to the toothless gear 110 for the C pins, and rotates together with the transmission shaft 56. As described above, the toothless gear 210 for the B pins and the toothless gear 110 for the C pins of the oil cylinder connection module 100 together constitute the switching gear G (refer to Figure 14 ).

[0181] In the following description, the rotation direction (the R2 direction in Figure 11 ) of the toothless gear 210 for the B pins when the arm connection module 200 makes a state transition from the inserted state (refer to Figure 15B ) to the retracted state (refer to Figure 14 ) is referred to as "forward", and the rotation direction (the R1 direction in Figure 14 ) of the toothless gear 210 for the B pins when making a state transition from the retracted state to the inserted state is referred to as "reverse".

[0182] Among the convex portions that make up the tooth portion 211 of the toothless gear 210 for the B pin, the convex portion provided at the forward end of the toothless gear 210 for the B pin is a positioning tooth (reference numeral omitted).

[0183] That is, when the arm connection module 200 transfers from the inserted state to the withdrawn state, the rotation direction R2 of the toothless gear 210 for the B pin is opposite to the rotation direction R1 of the toothless gear 110 for the C pin when the cylinder connection module 100 transfers from the inserted state to the withdrawn state.

[0184] A pair of rack bars 220A and 220B for the B pin are, for example, shaft members extending unidirectionally, and are arranged parallel to each other on the upper side (+ side in the Z direction) of the toothless gear 210 for the B pin in the Y direction. In addition, the rack bars 220A and 220B for the B pin are arranged centered on a synchronizing gear 230 (refer to Figure 14 ).

[0185] Each of the rack bars 220A and 220B for the B pin has an engaging portion 221 that engages with a locking piece 314a of the B pin holding portion 314. The locking piece 314a is provided, for example, at both ends in the Y direction (near the B pins 315A and 315B) of the B pin holding portion 314.

[0186] One of the rack bars 220B for the B pin has a driving side rack portion 222 on the surface closer to the toothless gear 210 for the B pin. In addition, the rack bars 220A and 220B for the B pin have synchronizing side rack portions 223 on the opposing surfaces in the X direction (refer to Figure 14 ). The synchronizing side rack portions 223 are respectively engaged with the synchronizing gear 230.

[0187] Only when the arm connection module 200 transfers from the inserted state (refer to Figure 11 ) to the withdrawn state (refer to Figure 15B ), the driving side rack portion 222 engages with the tooth portion 211 of the toothless gear 210 for the B pin.

[0188] Specifically, in the inserted state of the arm connection module 200, the first end surface (+ side in the Y direction) of the driving side rack portion 222 (illustration omitted) abuts against the positioning tooth (illustration omitted) in the tooth portion 211 of the toothless gear 210 for the B pin, or is opposed in the Y direction with a minute gap therebetween. In this state, if the toothless gear 210 for the B pin rotates in the R2 direction, the positioning tooth presses the first end surface toward the + side in the Y direction, and one of the rack bars 220B for the B pin moves toward the + side in the Y direction.

[0189] In addition, if one of the rack bars 220B for the B pin moves toward the + side in the Y direction, the synchronizing gear 230 rotates, and the other rack bar 220A for the B pin moves toward the - side in the Y direction (that is, the opposite side of the rack bar 220B for the B pin).

[0190] In addition, when the B-pin idler gear 210 rotates in the R1 direction starting from the inserted state of the arm connection module 200 shown in Figure 11 , the driving-side rack portion 222 does not mesh with the tooth portion 211 of the B-pin idler gear 210.

[0191] Thus, as the B-pin idler gear 210 rotates, the B-pin rack bars 220A and 220B move in their respective longitudinal directions (Y direction). One of the B-pin rack bars 220B is located on the most -Y side in the inserted state of the arm connection module 200 (see Figure 11 ), and in the withdrawn state, it is located on the most +Y side (see Figure 15B ). In addition, the other B-pin rack bar 220A is located on the most +Y side in the inserted state of the arm connection module 200 (see Figure 11 ), and in the withdrawn state, it is located on the most -Y side (see Figure 15B ).

[0192] As one of the B-pin rack bars 220B moves in the Y direction, one of the locking pieces 314a of the B-pin holding portion 314 abuts against the engaging portion 221 of the B-pin rack bar 220B. And, as the member supporting the B-pin 315B of the B-pin holding portion 314 moves in the Y direction, the B-pin 315B transfers to the inserted state or the withdrawn state.

[0193] Similarly, as the other B-pin rack bar 220A moves in the Y direction, the other locking piece 314a of the B-pin holding portion 314 abuts against the engaging portion 221 of the B-pin rack bar 220A. And, as the member supporting the B-pin 315A of the B-pin holding portion 314 moves in the Y direction, the B-pin 315A transfers to the inserted state or the withdrawn state.

[0194] In the above state transfer, the B-pins 315A and 315B move in opposite directions in the Y direction with respect to each other.

[0195] In addition, the movement of one of the B-pin rack bars 220B in the +Y direction and the movement of the other B-pin rack bar 220A in the -Y direction are restricted, for example, by abutting against a stopper (not shown) provided on the housing 58.

[0196] The B-pin biasing mechanism 240 biases the B-pin rack bars 220A and 220B in a direction away from each other. The B-pin biasing mechanism 240 is composed of, for example, a pair of compression coil springs. In the present embodiment, the B-pin biasing mechanism 240 is built into the B-pin rack bars 220A and 220B and biases the B-pin rack bars 220A and 220B toward the front end side.

[0197] If the electric motor 51 rotates in the R2 direction so that the arm connection module 200 is in the retracted state (see Figure 15B ), and the operation of the electric motor 51 stops, the arm connection module 200 automatically returns to the inserted state by the biasing force of the B-pin biasing mechanism 240 (see Figure 11 ). However, when the brake 52 is operating, the arm connection module 200 does not automatically return to the inserted state but remains in the retracted state.

[0198] In addition, the B-pin biasing mechanism 240 can directly apply a biasing force to the B-pin rack bars 220A and 220B, or can apply a biasing force through other components. Alternatively, the B-pin biasing mechanism 240 can be omitted, and based on the power of the electric motor 51, the arm connection module 200 makes a state transition from the retracted state to the inserted state. Even in this case, from the viewpoint of fail-safe protection, it is preferably structurally provided with the B-pin biasing mechanism 240 to reset to the safe-side inserted state in case of motor failure.

[0199] The locking mechanism 55 can prevent the following situation: an external force other than the power from the electric motor 51 acts on the cylinder connection module 100 (for example, the C-pin rack bar 120) or the arm connection module 200 (for example, the B-pin rack bars 220A and 220B), so that the cylinder connection module 100 and the arm connection module 200 simultaneously make a state transition to the retracted state. That is, the locking mechanism 55 prevents the operation of the connection mechanism of the other party in a state where the connection mechanism of at least one of the arm connection module 200 and the cylinder connection module 100 is operating.

[0200] Refer to Figures 16A - 16C to describe the locking mechanism 55. Figure 16A shows the situation when the cylinder connection module 100 and the arm connection module 200 are in the inserted state (neutral position), Figure 16B , Figure 16C respectively show the situations when the arm connection module 200 makes a transition from the inserted state to the retracted state. In addition, in Figures 16A - 16C , the switch gear G formed integrally with the C-pin partial-tooth gear 110 of the cylinder connection module 100 and the B-pin partial-tooth gear 210 of the arm connection module 200 is shown.

[0201] As shown in Figure 16A etc., the locking mechanism 55 has a first convex portion 551, a second convex portion 552, and a cam member 553 (locking-side rotating member).

[0202] The first convex portion 551 is integrally provided on the C-pin rack bar 120 of the cylinder connection module 100. Specifically, the first convex portion 551 is provided at a position adjacent to the input-side rack portion 121 of the C-pin rack bar 120.

[0203] The second convex portion 552 is integrally provided on one of the B-pin rack bars 220B of the arm connection module 200. Specifically, the second convex portion 552 is provided at a position adjacent to the driving-side rack portion 222 of the one B-pin rack bar 220B.

[0204] The cam member 553 is a plate-like member having a substantially crescent shape. The cam member 553 has a first cam receiving portion 553a at one end in the circumferential direction and a second cam receiving portion 553b at the other end.

[0205] The cam member 553 is, for example, externally fitted and fixed to the transmission shaft 56 at a position deviated in the X direction from the position where the switch gear G is externally fitted and fixed. Further, in the case of the present embodiment, the cam member 553 is externally fitted and fixed between the C-pin idler gear 110 and the B-pin idler gear 210. That is, the cam member 553 is coaxially provided with the switch gear G, and rotates about the transmission shaft 56 as a central axis together with the switch gear G as the transmission shaft 56 rotates.

[0206] Further, the cam member 553 may be integrally provided on the switch gear G. Alternatively, the cam member 553 may be integrally provided on at least one of the C-pin idler gear 110 and the B-pin idler gear 210.

[0207] As Figure 16B shown, in a state where the tooth portion G1 of the switch gear G meshes with the driving-side rack portion 222 of the B-pin rack bar 220B, the first cam receiving portion 553a of the cam member 553 is located on the + side in the Y direction relative to the first convex portion 551. That is, the first cam receiving portion 553a and the first convex portion 551 face each other with a minute gap in the Y direction. In this state, even if an external force ( Figure 16B the external force Fa in) acts on the C-pin rack bar 120 in the + side in the Y direction, it is absorbed by the gap.

[0208] If a greater external force Fa is applied to the C-pin rack bar 120 in the + side in the Y direction, the C-pin rack bar 120 moves from the Figure 16B position shown by the two-dot chain line in to the position shown by the solid line. In this state, the first convex portion 551 abuts against the first cam receiving portion 553a, and movement of the C-pin rack bar 120 in the + side in the Y direction can be prevented.

[0209] Further, as Figure 16C shown, in a state where the tooth portion G1 of the switch gear G meshes with the input-side rack portion 121 of the C-pin rack bar 120, the second cam receiving portion 553b of the cam member 553 is located on the + side in the Y direction relative to the second convex portion 552. That is, the second cam receiving portion 553b and the second convex portion 552 face each other with a minute gap in the Y direction. In this state, even if an external force in the + side in the Y direction is applied to the B-pin rack bar 220B (Figure 16C The external force Fb) therein will also be absorbed by the gap.

[0210] If a greater external force Fb is applied to the rack bar 220B for the B pin in the +Y direction, the rack bar 220B for the B pin moves from the position indicated by the two-dot chain line in Figure 16C to the position indicated by the solid line in the +Y direction. In this state, the second convex portion 552 abuts against the second cam receiving portion 553b, and the movement of the rack bar 220B for the B pin in the +Y direction can be prevented.

[0211] <Operation of the oil cylinder connection module 100 and the arm connection module 200>

[0212] Refer to Figures 17A - 17C and Figures 18A - 18C to illustrate an example of the operation of the oil cylinder connection module 100 and the arm connection module 200. Figures 17A - 17C and Figures 18A - 18C The operation shown, for example, is the extraction operation of the oil cylinder connection module 100 and the arm connection module 200 when the front arm 31 is extended.

[0213] Hereinafter, the rotation of the electric motor 51 when the arm connection module 200 is transferred from the inserted state to the extracted state is referred to as "forward rotation", and the rotation of the electric motor 51 when the oil cylinder connection module 100 is transferred from the inserted state to the extracted state is referred to as "reverse rotation".

[0214] Figures 17A - 17C is a schematic diagram for explaining the operation of the oil cylinder connection module 100. Figures 17A - 17C It shows the operation when the oil cylinder connection module 100 is transferred from the inserted state to the extracted state. In Figures 17A - 17C the switch gear G formed integrally with the toothless gear 110 for the C pin and the toothless gear 210 for the B pin is shown. In addition, in Figures 17A - 17C the locking mechanism 55 is omitted.

[0215] As Figure 17A shown, in the contracted state before the front arm 31 is extended, the oil cylinder connection module 100 is in a neutral state. That is, the C pin 150 engages with the C pin receiving portion 311 of the arm 31, and the front arm 31 is connected to the oil cylinder connection module 100.

[0216] When the oil cylinder connection module 100 is transferred from the inserted state to the extracted state, the power of the electric motor 51 is transmitted to the C pins 150A and 150B through the following first path and second path.

[0217] The first path is: the slotted gear 110 for the C pin → the rack bar 120 for the C pin → the first gear set 130 → one C pin 150A. The second path is: the slotted gear 110 for the C pin → the rack bar 120 for the C pin → the second gear set 140 → the other C pin 150B.

[0218] As Figure 17B shown, if the electric motor 51 rotates in reverse, the slotted gear 110 for the C pin rotates in the R1 direction. Along with the rotation of the slotted gear 110 for the C pin, the rack bar 120 for the C pin is displaced in the + side of the Y direction ( Figures 17A - 17C the right side in Figures 17A - 17C ). Along with this, in the first path, through the first gear set 130, one C pin 150A is displaced in the - side of the Y direction ( Figures 17A - 17C the left side in

[0219] ). In the second path, through the second gear set 140, the other C pin 150B is displaced in the + side of the Y direction ( Figure 17C the right side in

[0220] Figures 18A - 18C ). That is, when the oil cylinder connection module 100 transfers from the inserted state to the withdrawn state, one C pin 150A and the other C pin 150B are displaced in the direction of approaching each other. Figures 18A - 18C represents the operation when the arm connection module 200 transfers from the inserted state to the withdrawn state. In Figures 18A - 18C , the switch gear G formed by integrating the slotted gear 110 for the C pin and the slotted gear 210 for the B pin is shown. In addition, in Figures 18A - 18C , the locking mechanism 55 is omitted.

[0221] As Figure 18A shown, in the contracted state before the front arm 31 extends, the oil cylinder connection module 100 and the arm connection module 200 are in a neutral state. That is, the front arm 31 is connected to the intermediate arm 32 through the B pin 315 and cannot move in the telescopic direction relative to the intermediate arm 32.

[0222] When the arm connection module 200 transfers from the inserted state to the withdrawn state, the power of the electric motor 51 is transmitted through the path: the slotted gear 210 for the B pin → one rack bar 220B for the B pin → the synchronizing gear 230 → the other rack bar 220A for the B pin.

[0223] AsFigure 18B As shown, if the electric motor 51 rotates forward, the B-pin with missing teeth gear 210 rotates in the R2 direction. Along with the rotation of the B-pin with missing teeth gear 210, one of the B-pin racks 220B displaces in the + side of the Y direction ( Figures 18A - 18C the right side in Figures 18A - 18C ). In addition, the synchronizing gear 230 rotates, and the other B-pin rack 220A is displaced in the - side of the Y direction (

[0224] the left side in Figure 18C ) by receiving the rotation of the synchronizing gear 230. That is, when the arm connection module 200 transfers from the inserted state to the withdrawn state, one of the B-pin racks 220B and the other B-pin rack 220A are displaced in the direction approaching each other. Accordingly, the B-pin holding part 314 connected to the B-pin racks 220A and 220B also contracts, and the B-pin 315 held in the B-pin holding part 314 is slowly pulled out from the B-pin receiving part 322.

[0225] <Control during telescoping operation>

[0226] Figure 19 is a timing chart showing an example of the control during the extending operation of the telescopic arm 30. For simplicity, the case where the front arm 31 extends from the fully retracted state is described. In addition, the inserted state and withdrawn state of the B-pin 315 correspond to the inserted state and withdrawn state of the arm connection module 200, and the inserted state and withdrawn state of the C-pin 150 correspond to the inserted state and withdrawn state of the cylinder connection module 100. The ON (start) / OFF (stop) switching of the electric motor 51, the brake 52, and the clutch 61 is controlled by the control device 70.

[0227] Figure 19 The interval T0 to T1 in Figure 17A is the retracted state at the initial stage of the extending operation, and the cylinder connection module 100 and the arm connection module 200 are in the neutral state (refer to Figure 18A ). That is, the front arm 31 is connected to the intermediate arm 32 by the B-pin 315 and cannot move in the telescoping direction relative to the intermediate arm 32. In addition, the C-pin 150 engages with the C-pin receiving part 311 of the front arm 31, and the front arm 31 and the cylinder part 42 are in the connected state.

[0228] The states of the respective mechanical elements in the interval T0 to T1 are as follows.

[0229] Electric motor 51: OFF (stop)

[0230] Clutch 61: OFF (Closed)

[0231] Brake 52: OFF (Closed)

[0232] C pin 150 (cylinder connection module 100): Inserted state

[0233] B pin 315 (arm connection module 200): Inserted state

[0234] If the control device 70 receives an operator's operation to extend the telescopic arm 30 (timing T1), it controls the clutch 61 to the ON (activated) state (connected state) and rotates the electric motor 51 forward. The B pin 315 slowly transfers from the inserted state to the withdrawn state.

[0235] The states of the respective mechanical elements in the period T1 to T2 are as follows.

[0236] Electric motor 51: ON (Activated)

[0237] Clutch 61: ON (Activated)

[0238] Brake 52: OFF (Closed)

[0239] C pin 150 (cylinder connection module 100): Inserted state

[0240] B pin 315 (arm connection module 200): Inserted state → withdrawn state (withdrawal action)

[0241] At this time, if the B pin 315 is hooked on the B pin receiving portion 322 on the base end side of the intermediate arm 32 and is difficult to withdraw, the rotating elements in the power transmission path from the electric motor 51 to the arm connection module 200 cannot rotate smoothly, resulting in an overload. Also, a large current flows through the electric motor 51, posing a risk of overheating or burnout.

[0242] In the present embodiment, a torque limiter 63 is arranged on the power transmission path, and the load applied to the mechanical elements in the power transmission path is kept below a specified value. Therefore, it is possible to prevent damage to the mechanical elements caused by the difficulty in withdrawing the B pin 315 during the withdrawal operation of the B pin 315.

[0243] The control device 70 determines the state of the B pin 315 based on the detection result of the position detection device 54 or the like. If the B pin 315 transfers to the withdrawn state (timing T2), it maintains the clutch 61 in the ON (activated) state and stops the electric motor 51. In addition, it places the brake 52 in the ON (activated) state to maintain the withdrawn state of the B pin 315.

[0244] In addition, the timing for turning the electric motor 51 OFF and the timing for turning the brake 52 ON are appropriately controlled by the control device 70. For example, by turning the brake 52 ON and then turning the electric motor 51 OFF, the retracted state of the B pin 315 can be reliably maintained.

[0245] At timing T2, the B pin 315 completely disengages from the base-end side B pin receiving portion 322, and the front end arm 31 and the intermediate arm 32 become unconnected. Omitting the illustration, in the interval T2 - T3, the control device 70 controls the telescopic actuator 40 to move the cylinder portion 42 in the extending direction. Along with this, the front end arm 31 connected to the cylinder portion 42 by the cylinder connection module 100 moves in the extending direction.

[0246] The states of the respective mechanical elements in the interval T2 - T3 are as follows.

[0247] Electric motor 51: OFF

[0248] Clutch 61: ON

[0249] Brake 52: ON

[0250] C pin 150 (cylinder connection module 100): Inserted state

[0251] B pin 315 (arm connection module 200): Retracted state

[0252] When the front end arm 31 moves to a specified position and becomes extended (timing T3), the control device 70 controls the clutch 61 and the brake 52 to the OFF state. By the biasing force of the B pin biasing mechanism 240, the arm connection module 200 returns to the neutral state. Along with this, the B pin 315 transfers from the retracted state to the inserted state and passes through the front end side B pin receiving portion 323.

[0253] The states of the respective mechanical elements in the interval T3 - T4 are as follows.

[0254] Electric motor 51: OFF

[0255] Clutch 61: OFF

[0256] Brake 52: OFF

[0257] C pin 150 (cylinder connection module 100): Inserted state

[0258] B pin 315 (arm connection module 200): Retracted state → Inserted state (insertion action)

[0259] Thus, in the insertion operation of the B pin 315, it is reset to the neutral state by the biasing mechanism 240 for the B pin. In this case, if the power transmission path from the electric motor 51 to the arm connection module 200 is connected, then along with the insertion operation of the B pin 315, the electric motor 51 rotates in the direction opposite to the rotation direction during the extraction operation. Moreover, the rotating elements including the electric motor 51 do not stop at the neutral position due to inertia force, and there may be a thrust force that causes the switch gear G to rotate in the direction of pulling away from the C pin 150 due to overrun operation.

[0260] In response to this, in the present embodiment, the clutch 61 is disposed in the power transmission path, and when it is reset to the neutral state by the biasing mechanism 240 for the B pin, the power transmission from the arm connection module 200 to the electric motor 51 is cut off. Therefore, it is possible to prevent the C pin 150 from temporarily shifting to the extraction state during the insertion operation of the B pin 315, thereby making the operation unstable.

[0261] If the B pin 315 is fully engaged with the front-end side B pin receiving portion 323 (timing T4), then the control device 70B causes the C pin 150 to shift to the extraction state in order to return the telescopic actuator 40 to the retracted state. That is, at timing T5, the control device 70 controls the clutch 61 to the ON (activated) state (connected state), and reverses the electric motor 51. The C pin 150 slowly shifts from the inserted state to the extraction state.

[0262] The states of the respective mechanical elements in the period T5 - T6 are as follows.

[0263] Electric motor 51: ON (activated)

[0264] Clutch 61: ON (activated)

[0265] Brake 52: OFF (released)

[0266] C pin 150 (cylinder connection module 100): inserted state → extraction state (extraction operation)

[0267] B pin 315 (arm connection module 200): inserted state

[0268] At this time, if the C pin 150 is hooked on the C pin receiving portion 311 of the front-end arm 31 or the like and is difficult to extract, then the rotating elements in the power transmission path from the electric motor 51 to the cylinder connection module 100 cannot rotate smoothly, resulting in an overload. Moreover, a large current flows through the electric motor 51, and there is a risk of overheating or burnout.

[0269] In this embodiment, a torque limiter 63 is arranged on the power transmission path, and the load applied to the mechanical elements in the power transmission path is maintained below a specified value. Therefore, it is possible to prevent damage to the mechanical elements due to the difficulty of pulling out the C-pin 150 during the pulling-out operation of the C-pin 150.

[0270] The control device 70 determines the state of the C-pin 150 based on the detection result of the position detection device 54, etc. If the C-pin 150 transitions to the pulled-out state (timing T6), the clutch 61 is maintained in the ON (activated) state and the electric motor 51 is stopped. In addition, the brake 52 is turned ON (activated) to maintain the pulled-out state of the C-pin 150.

[0271] At timing T6, the C-pin 150 completely disengages from the C-pin receiving portion 311 of the front end arm 31, and the cylinder connection module 100 and the front end arm 31 become a non-connected state. Although not shown, in the period T6 to T7, the control device 70 controls the telescopic actuator 40 to move the cylinder portion 42 in the retracting direction. At this time, since the cylinder portion 42 is in a non-connected state with the front end arm 31, the intermediate arm 32, and the base end arm 33, the cylinder portion 42 moves alone in the retracting direction.

[0272] The states of the respective mechanical elements in the period T6 to T7 are as follows.

[0273] Electric motor 51: OFF (closed)

[0274] Clutch 61: ON (activated)

[0275] Brake 52: ON (activated)

[0276] C-pin 150 (cylinder connection module 100): Pulled-out state

[0277] B-pin 315 (arm connection module 200): Inserted state

[0278] If the telescopic actuator 40 becomes the retracted state (timing T7), the control device 70 controls the clutch 61 and the brake 52 to the OFF (closed) state. By the biasing force of the C-pin biasing mechanism 160, the cylinder connection module 100 is reset to the neutral state. Along with this, the C-pin 150 transitions from the pulled-out state to the inserted state and engages with the C-pin receiving portion 321 of the intermediate arm 32. In addition, the B-pin holders 324 of the intermediate arm 32 are engaged with the B-pin rack bars 220A, 220B.

[0279] The states of the respective mechanical elements in the period T7 to T8 are as follows.

[0280] Electric motor 51: OFF (closed)

[0281] Clutch 61: OFF (closed)

[0282] Brake 52: OFF (Closed)

[0283] C-pin 150 (cylinder connection module 100): Withdrawal state → Insertion state (insertion action)

[0284] B-pin 315 (arm connection module 200): Inserted state

[0285] Thus, during the insertion action of the C-pin 150, it is reset to the neutral state by the biasing mechanism 160 for the C-pin. In this case, if the power transmission path from the electric motor 51 to the cylinder connection module 100 is connected, then along with the insertion action of the C-pin 150, the electric motor 51 rotates in the direction opposite to the rotation direction during the withdrawal action. Moreover, the rotating elements including the electric motor 51 do not stop at the neutral position due to inertia force, and there is a possibility of generating a thrust force that rotates the switching gear G in the direction of pulling away from the B-pin 325 due to overrun operation.

[0286] In response to this, in the present embodiment, a clutch 61 is disposed in the power transmission path, and when it is reset to the neutral state by the biasing mechanism 160 for the C-pin, the transmission of power from the cylinder connection module 100 to the electric motor 51 is cut off. Therefore, it is possible to prevent the B-pin 325 from temporarily shifting to the withdrawal state during the insertion action of the C-pin 150, thereby making the operation unstable.

[0287] If the C-pin 150 is fully engaged with the C-pin receiving portion 321 of the intermediate arm 32 (timing T8), then the neutral state is maintained. In addition, when the intermediate arm 32 is extended, the same operation as described above is performed. Further, when the front arm 31 or the intermediate arm 32 is contracted, the operation in the opposite direction to the above is performed.

[0288] Here, generally, lubricating oil is applied to the mechanical elements constituting the pin insertion / withdrawal actuator 50 so that the withdrawal action and the insertion action of the B-pin 315 and the C-pin 150 are performed smoothly. In this case, if the viscosity of the lubricating oil becomes high due to the surrounding environmental temperature or aging, it may hinder the insertion / withdrawal operation of the B-pin 315 and the C-pin 150. In particular, since the insertion action of the B-pin 315 and the C-pin 150 is performed by applying force, there is a risk that the high-viscosity lubricating oil becomes a resistance and the operation time becomes unstable.

[0289] Then, in the present embodiment, when the C-pin 150 is reset to the insertion state by the biasing force of the biasing mechanism 160 for the C-pin, and when the B-pin 315 is reset to the insertion state by the biasing force of the biasing mechanism 240 for the B-pin, the control device 70C executes motor assistance processing for operating the electric motor 51.

[0290] Figure 20This is a timing chart for explaining the extension operation of the telescopic arm 30 to which motor-assisted processing is applied.

[0291] As Figure 20 shown, when the insertion operation of the B pin 315 is performed in the period T3 to T4, the control device 70 reverses the electric motor 51 for a short time (for example, 0.01 to 0.5 sec). Further, when the insertion operation of the C pin 150 is performed in the period T7 to T8, the control device 70 rotates the electric motor 51 forward. Accordingly, the power of the electric motor 51 releases the state in which the C pin 150 or the B pin 315 is difficult to move due to the viscosity of the lubricating oil, and the subsequent reset to the neutral state by the biasing force of the C-pin biasing mechanism 160 or the B-pin biasing mechanism 240 can be smoothly performed.

[0292] This motor-assisted processing can always be performed during the insertion operations of the B pin 315 and the C pin 150, or can be performed only when a specified condition is satisfied. The specified conditions include the ambient temperature (for example, -10°C or lower), the usage time, and the like. Further, the operator can manually set whether to perform the motor-assisted processing. Further, the motor-assisted processing can be selectively performed for the B pin 315 and the C pin 150.

[0293] Furthermore, the control device 70 can determine the drive start timing and the drive time of the electric motor 51 in the motor-assisted processing according to the ambient temperature. Accordingly, since appropriate motor-assisted processing is performed, it is possible to prevent a thrust from being generated in the direction of pulling out the C pin 150 or the B pins 315 and 325 due to over-running.

[0294] Thus, the mobile crane 1 (working machine) according to the present embodiment includes: a telescopic boom 30 having a first boom (e.g., the front boom 31) and a second boom (e.g., the intermediate boom 32) that are overlapped in a telescopic manner; a telescopic actuator 40 that moves the first boom relative to the second boom in the telescopic direction; an electric motor 51 (electrical drive source) disposed in the cylinder portion 42 (movable portion) of the telescopic actuator 40; a C pin 150 (first fixing pin) that connects the telescopic actuator 40 and the first boom; a cylinder connection module 100 (first connection mechanism) that operates based on the power of the electric motor 51 to insert and remove the C pin 150, thereby switching the connection state and non-connection state between the telescopic actuator 40 and the first boom; B pins 315 and 325 (second fixing pins) that connect the first boom and the second boom; an arm connection module 200 (second connection mechanism) that operates based on the power of the electric motor 51 to insert and remove the B pins 315 and 325, thereby switching the connection state and non-connection state between the first boom and the second boom; and a torque limiter 63 disposed between the electric motor 51 and the cylinder connection module 100 or the arm connection module 200 to keep the load acting on the mechanical element that constitutes the power transmission path from the electric motor 51 to the cylinder connection module 100 or the arm connection module 200 below a specified value.

[0295] Specifically, in the mobile crane 1, the electric motor 51 (electrical drive source) is configured as a rotary electric motor, and the torque limiter 63 is a friction type torque limiter. The friction type torque limiter is installed on the transmission shaft 56 of the power transmission path, and in the case where a load greater than the specified value is generated, the input side element and the output side element are combined in a manner that causes sliding.

[0296] According to the mobile crane 1, both the cylinder connection module 100 and the arm connection module 200 are electric type. Therefore, there is no need to provide a hydraulic circuit in the internal space of the telescopic boom 30 as in the conventional structure. Therefore, the space originally used by the hydraulic circuit can be effectively utilized, and the degree of freedom in design in the internal space of the telescopic boom 30 can be improved.

[0297] In addition, a torque limiter 63 is disposed on the power transmission path, and the load applied to the mechanical elements in the power transmission path is kept below a specified value. Therefore, it is possible to prevent damage to the mechanical elements due to the difficulty in removing the C pin 150 and the B pins 315 and 325 during the extraction operation of the C pin 150 and the B pins 315 and 325.

[0298] Therefore, according to the mobile crane 1, it is possible to achieve an improvement in the degree of freedom in design around the telescopic boom 30 and the reliability during boom telescoping.

[0299] In addition, the mobile crane 1 is provided with a speed reducer 62 that decelerates and outputs the driving speed of the electric motor 51 (electrical drive source). In the power transmission path, the torque limiter 63 is arranged at the subsequent stage of the speed reducer 62. Accordingly, compared with the case where it is arranged at the preceding stage of the speed reducer 62, the influence of the tolerance and deviation of the torque setting value can be reduced.

[0300] In addition, the mobile crane 1 is provided with a speed reducer 62 that decelerates and outputs the driving speed of the electric motor 51 (electrical drive source). In the power transmission path, the torque limiter 63 is arranged at the preceding stage of the speed reducer 62. Accordingly, the torque setting value becomes smaller, and thus miniaturization of the torque limiter 63 can be achieved.

[0301] As described above, based on the embodiments, the invention made by the present inventor has been specifically described. However, the present invention is not limited to the above embodiments and can be modified within the scope not departing from its gist.

[0302] For example, as the electric motor 51, a hollow motor having a hollow stator arranged inside and a rotor arranged outside may be applicable, which is arranged on the outer periphery of the piston rod portion 41, and a transmission gear (not shown) of the transmission mechanism 53 meshes with a gear provided on the rotor.

[0303] In addition, the arrangement of the electric motor 51 shown in the embodiment is an example, and the electric motor 51 may also be arranged such that the output shaft (not shown) extends in the Y direction or the Z direction.

[0304] In addition, the electric motor 51 is not limited to a rotary motor, and a linear motor (direct-acting actuator) that outputs linear motion can also be applicable.

[0305] In addition, the working machine related to the present invention is not limited to a mobile crane, and can also be applicable to other working machines having a telescopic boom (for example, an aerial work platform).

[0306] It should be considered that all the contents of the embodiments disclosed this time are merely illustrative and not restrictive. The scope of the present invention is not the above description but is shown by the claims, including all modifications within the meaning and scope equivalent to the claims.

[0307] All the disclosure contents of the specification, drawings, and abstract included in Japanese Patent Application No. 2019-151528 filed on August 21, 2019 are incorporated herein by reference.

[0308] Explanation of Reference Numerals

[0309] 1 Mobile crane (working machine)

[0310] 30 Telescopic boom

[0311] 31 Front boom

[0312] 311 C-pin receiving part

[0313] 314 B-pin holding part

[0314] 315, 315A, 315B B-pins

[0315] 32 Intermediate arm

[0316] 321 C-pin receiving part

[0317] 322 Base-end side B-pin receiving part

[0318] 323 Tip-end side B-pin receiving part

[0319] 324 B-pin holding part

[0320] 325 B-pin

[0321] 33 Base-end arm

[0322] A Telescopic device

[0323] 40 Actuator for telescoping

[0324] 41 Piston rod part

[0325] 42 Cylinder part (movable part)

[0326] 50 Actuator for pin insertion / removal

[0327] 51 Electric motor (electrical drive source)

[0328] 52 Brake

[0329] 53 Transmission mechanism

[0330] 54 Position detection device

[0331] 55 Locking mechanism

[0332] 56 Transmission shaft

[0333] 61 Clutch

[0334] 62 Reducer

[0335] 63 Torque limiter

[0336] 100 Cylinder connection module (first connection mechanism)

[0337] 110 Missing-tooth gear for C-pin

[0338] 120 Rack bar for C-pin

[0339] 130 First gear set

[0340] 140 Second gear set

[0341] 150, 150A, 150B C pins

[0342] 160 Biasing mechanism for C pin (first biasing mechanism)

[0343] 200 Arm connection module (second connection mechanism)

[0344] 210 Toothless gear for B pin

[0345] 220A, 220B Rack bars for B pin

[0346] 230 Synchronous gear

[0347] 240 Biasing mechanism for B pin (second biasing mechanism)

Claims

1. An operating machine, comprising: A telescopic arm having a first arm and a second arm that overlap in a telescopic manner; A telescopic actuator that moves the first arm relative to the second arm in the telescopic direction; An electric motor disposed on a movable part of the telescopic actuator; A first fixing pin that connects the telescopic actuator and the first arm; A first connecting mechanism disposed on the movable part of the telescopic actuator, which operates based on the power of the electric motor to insert and remove the first fixing pin, thereby switching the connection state and the non-connection state between the telescopic actuator and the first arm; A second fixing pin that connects the first arm and the second arm; A second connecting mechanism disposed on the movable part of the telescopic actuator, which operates based on the power of the electric motor to insert and remove the second fixing pin, thereby switching the connection state and the non-connection state between the first arm and the second arm; A switching gear that selectively transmits the power of the electric motor to one of the first connecting mechanism and the second connecting mechanism; And A torque limiter disposed between the electric motor and the switching gear, which keeps the load acting on the mechanical element, which constitutes the power transmission path from the electric motor to the switching gear, below a specified value.

2. The operating machine according to claim 1, wherein The electric motor is configured as a rotary electric motor, The torque limiter is a friction type torque limiter, which is installed on the transmission shaft of the power transmission path and, when a load greater than the specified value is generated, causes the input side element and the output side element to be combined in a sliding manner.

3. The operating machine according to claim 1 or 2, wherein The operating machine is provided with a speed reducer that decelerates the driving speed of the power of the electric motor and outputs the power of the electric motor, In the power transmission path, the torque limiter is disposed at the subsequent stage of the speed reducer.

4. The operating machine according to claim 1 or 2, wherein The operating machine is provided with a speed reducer that decelerates the driving speed of the power of the electric motor and outputs the power of the electric motor, In the power transmission path, the torque limiter is disposed at the previous stage of the speed reducer.

Images