Patent Description:
Conventionally, there is known a mobile crane including a telescopic boom in which a plurality of boom elements is disposed while being overlapped in a nested manner (also referred to as a telescopic manner) (see, for example, Patent Literature <NUM>). The telescopic boom is configured to be telescopic stage by stage, for example, by a telescoping actuator disposed inside the innermost boom element.

Specifically, in the telescopic boom, boom elements adjacent to each other inside and outside are connected to each other by a boom-connecting pin (hereinafter, referred to as the "B pin"). When connection by the B pin is released, a boom element on an inner side is movable in a telescoping direction with respect to a boom element on an outer side. The movable boom element is connected to a movable portion of the telescoping actuator by a cylinder-connecting pin (hereinafter, referred to as the "C pin"). The telescoping actuator includes, for example, a hydraulic cylinder having a piston rod part and a cylinder part, and the cylinder part functions as a movable portion to telescope the boom element.

In addition, the insertion and removal operation of the B pin and the C pin is exclusively controlled by a pin insertion/removal actuator provided in the movable portion of the telescoping actuator, and a connection state between the boom elements by the B pin and a connection state between the cylinder and the boom by the C pin are not simultaneously released (so-called interlock).

Document <CIT> discloses a work machine according to the preamble of claim <NUM>.

Incidentally, a hydraulic actuator is conventionally used as the pin insertion/removal actuator, and a pipe and a hydraulic circuit for supplying hydraulic oil to the actuator are provided around the telescopic boom. For this reason, design around the telescopic boom may be spatially limited, and this limitation in the design may restrict downsizing and light-weighting of the telescopic boom.

In addition, since the viscosity of the hydraulic oil varies according to environmental temperature or the like, operation time is unstable, and there is a large influence particularly in low temperature environments, which causes malfunction.

An object of the present invention is to provide a work machine that allows an improvement in the degree of freedom in terms of design around a telescopic boom and an increase in the reliability when the boom is telescoping.

A work machine according to the present invention includes:.

According to the present invention, it is possible to improve the degree of freedom in terms of design around a telescopic boom and increase the reliability when the boom is telescoping.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.

In the present embodiment, a mobile crane <NUM> that is an example of a work machine according to the present invention will be described.

<FIG> is a view illustrating a state during traveling of the mobile crane <NUM> according to an embodiment of the present invention. <FIG> is a diagram illustrating a state of the mobile crane <NUM> during work.

The mobile crane <NUM> illustrated in <FIG> and <FIG> is a so-called rough terrain crane including an upper revolving body <NUM> and a lower traveling body <NUM>.

The upper revolving body <NUM> includes a revolving frame <NUM>, a cabin <NUM> (cab), a derricking cylinder <NUM>, a jib <NUM>, a hook <NUM>, a bracket <NUM>, a telescopic boom <NUM>, a counter weight CW, a hoisting device (winch, not illustrated), and the like.

The revolving frame <NUM> is revolvably supported by the lower traveling body <NUM> via a revolving suspension (not illustrated). The cabin <NUM>, the derricking cylinder <NUM>, the bracket <NUM>, the telescopic boom <NUM>, the counter weight CW, the hoisting device (not illustrated), and the like are attached to the revolving frame <NUM>.

The cabin <NUM> is disposed, for example, in front of the revolving frame <NUM>. In the cabin <NUM>, in addition to a seat on which an operator sits and various instruments, an operation part, a display part, a sound output part, and the like used when crane work and travelling operation are performed are disposed.

The derricking cylinder <NUM> is installed between the revolving frame <NUM> and the telescopic boom <NUM>. The telescopic boom <NUM> is derricked within a predetermined derricking angle range (for example, <NUM>° to <NUM>°) by the telescoping of the derricking cylinder <NUM>.

The jib <NUM> is rotatably attached to a distal end (boom head) of the telescopic boom <NUM> in a case where a lifting height is increased. The jib <NUM> is rotated forward, thereby being projected forward from the telescopic boom <NUM>.

The hook <NUM> is a hanging tool having a hook shape and has a main winding hook and an auxiliary winding hook. The hook <NUM> is attached to a wire rope <NUM> wound around a sheave at a distal end part of the telescopic boom <NUM> or a distal end part of the jib <NUM>. As the wire rope <NUM> is wound up or paid out by a hoisting device (not illustrated), the hook <NUM> moves up and down.

The counter weight CW is attached to a rear part of the revolving frame <NUM>. The counter weight CW has a plurality of unit weights and can be set to have different weights depending on a combination of the unit weights.

The telescopic boom <NUM> is rotatably attached to the bracket <NUM> via a support shaft (foot pin, reference sign is omitted). The telescopic boom <NUM> has a plurality of boom elements including a distal end boom <NUM>, an intermediate boom <NUM>, and a proximal end boom <NUM>, and these boom elements are disposed while being overlapped in a nested manner (so-called telescopic structure). A telescoping actuator <NUM> (see <FIG>) disposed inside telescopes, whereby the distal end boom <NUM> and the intermediate boom <NUM> among the plurality of boom elements slide and telescope in a telescoping direction with respect to the proximal end boom <NUM>. Meanwhile, the proximal end boom <NUM> is not movable in a telescoping direction. The state of the telescopic boom <NUM> changes from a contracted state illustrated in <FIG> to an extended state illustrated in <FIG> by extending the boom elements in order from the boom element disposed on an inner side (that is, the distal end boom <NUM>).

In addition, a boom head (reference sign is omitted) having a sheave (reference sign is omitted) is disposed at a distal end part of the distal end boom <NUM>. In addition, a work attachment such as a bucket may be attached to the boom head. Note that in the telescopic boom <NUM>, the number of stages of the intermediate boom <NUM> is not particularly limited.

The lower traveling body <NUM> includes a vehicle body frame <NUM>, wheels <NUM> and <NUM>, outriggers OR1 and OR2, an engine (not illustrated), and the like.

Driving force of the engine is transmitted to the wheels <NUM> and <NUM> via a transmission (not illustrated). The mobile crane <NUM> travels by the rotation of the wheels <NUM> and <NUM> by the driving force of the engine. In addition, steering angles (traveling directions) of the wheels <NUM> and <NUM> change in accordance with the operation of a steering wheel (not illustrated) provided in the cabin <NUM>.

The outriggers OR1 and OR2 are housed in the vehicle body frame <NUM> during traveling. Meanwhile, the outriggers OR1 and OR2 project in a horizontal direction and a vertical direction during work (during the operation of the upper revolving body <NUM>), lift and support the entire vehicle body, and stabilize a posture.

As described above, the mobile crane <NUM> is a self-travelling crane using the wheels <NUM> and <NUM> for a travelling unit of the lower traveling body <NUM>, and travelling operation and crane operation can be performed from one cab.

Note that examples of the mobile crane <NUM> include an all-terrain crane, a truck crane, and a truck loader crane (also referred to as a cargo crane) in addition to a rough terrain crane.

<FIG> and <FIG> are schematic views for describing a structure and extending operation of the telescopic boom <NUM>. <FIG> and <FIG> are vertical cross sections along a width direction of the telescopic boom <NUM>, the right side in the figures is the proximal end side of the telescopic boom <NUM>, and the left side in the figures is the distal end side of the telescopic boom <NUM>. Here, in order to simplify description, the telescopic boom <NUM> in which the intermediate boom <NUM> is of a one-stage composition will be described as an example.

As illustrated in <FIG> and <FIG>, the telescopic boom <NUM> has a configuration substantially similar to a configuration of a conventionally known telescopic boom. The telescopic boom <NUM> has, for example, a structure symmetrical in the width direction with respect to a telescopic axis. A telescopic device A for telescoping the telescopic boom <NUM> is disposed inside the telescopic boom <NUM>.

In the telescopic boom <NUM>, the distal end boom <NUM> and the intermediate boom <NUM> are connected to each other with a boom-connecting pin (hereinafter, referred to as the "B pin") <NUM> provided in the distal end boom <NUM>, and the intermediate boom <NUM> and the proximal end boom <NUM> are connected to each other with a B pin <NUM> provided in the intermediate boom <NUM>. In addition, each of the distal end boom <NUM>, the intermediate boom <NUM>, and the proximal end boom <NUM> is connected to the telescoping actuator <NUM> by a cylinder-connecting pin (hereinafter, referred to as the "C pin") <NUM>. The distal end boom <NUM> or the intermediate boom <NUM> connected to the telescoping actuator <NUM> by the C pin <NUM> is a boom element to be telescoped.

The distal end boom <NUM> has a cylindrical shape and has an internal space capable of accommodating the telescopic device A. The distal end boom <NUM> has a C pin receiving part <NUM>, a B pin holding part <NUM>, and the B pin <NUM> at a proximal end part.

Each of a pair of the C pin receiving parts <NUM> is configured to be engageable with and disengageable from the C pin <NUM> (first fixing pin) provided in a pin insertion/removal actuator <NUM>. The C pin receiving parts <NUM> are disposed, for example, coaxially with each other.

The B pin holding part <NUM> is fixed to a frame of the distal end boom <NUM> on the proximal end side of the C pin receiving part <NUM> and holds the B pin <NUM> (second fixing pin) so that the B pin <NUM> is movable forward and backward. A pair of the B pins <NUM> is disposed, for example, coaxially at the B pin holding part <NUM> and is biased in directions opposite to each other toward the intermediate boom <NUM> on the outer side by the biasing force of a biasing member. That is, in normal times in which the distal end boom <NUM> is not telescoped, the B pin <NUM> is inserted into a proximal end side B pin receiving part <NUM> or a distal end side B pin receiving part <NUM> of the intermediate boom <NUM> by the biasing force of the biasing member, and the B pin <NUM> is maintained in this state.

The intermediate boom <NUM> has a cylindrical shape and has an internal space capable of accommodating the distal end boom <NUM>. The intermediate boom <NUM> has a C pin receiving part <NUM>, the proximal end side B pin receiving part <NUM>, and a B pin holding part <NUM> at a proximal end part and includes the distal end side B pin receiving part <NUM> at a distal end part.

Each of a pair of the C pin receiving parts <NUM> is configured to be engageable with and disengageable from the C pin <NUM> (first fixing pin). The C pin receiving parts <NUM> are disposed, for example, coaxially with each other.

A pair of the proximal end side B pin receiving parts <NUM> is provided on the proximal end side of the C pin receiving part <NUM> and is disposed coaxially with each other. A pair of the distal end side B pin receiving parts <NUM> is provided at a distal end part of the intermediate boom <NUM> and disposed coaxially with each other. Each of the proximal end side B pin receiving part <NUM> and the distal end side B pin receiving part <NUM> is configured to allow insertion and removal of the B pin <NUM> of the distal end boom <NUM>.

The B pin holding part <NUM> is fixed to a frame of the intermediate boom <NUM> on the proximal end side of the proximal end side B pin receiving part <NUM>, and holds the B pin <NUM> (second fixing pin) so that the B pin <NUM> is movable forward and backward. A pair of the B pins <NUM> is disposed, for example, coaxially at the B pin holding part <NUM> and is biased in directions opposite to each other toward the proximal end boom <NUM> on the outer side by the biasing force of the biasing member. That is, in normal times in which the intermediate boom <NUM> is not telescoped, the B pin <NUM> is inserted into a proximal end side B pin receiving part <NUM> or a distal end side B pin receiving part <NUM> of the proximal end boom <NUM> by the biasing force of the biasing member and is maintained in this state.

The proximal end boom <NUM> has a cylindrical shape and has an internal space capable of accommodating the intermediate boom <NUM>. The proximal end boom <NUM> has the proximal end side B pin receiving part <NUM> at a proximal end part and the distal end side B pin receiving part <NUM> at a distal end part.

A pair of the proximal end side B pin receiving parts <NUM> is disposed coaxially with each other. A pair of the distal end side B pin receiving parts <NUM> is provided at a distal end part of the proximal end boom <NUM> and disposed coaxially with each other. Each of the proximal end side B pin receiving part <NUM> and the distal end side B pin receiving part <NUM> is configured to allow insertion and removal of the B pin <NUM> of the intermediate boom <NUM>.

The B pins <NUM> and <NUM> are displaced in an axial direction thereof on the basis of the operation of a boom connection module <NUM> included in the pin insertion/removal actuator <NUM>.

Specifically, the B pin <NUM> is inserted so as to be bridged over the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the intermediate boom <NUM>. As a result, the distal end boom <NUM> and the intermediate boom <NUM> are connected to each other and brought into a connection state. Meanwhile, when the B pin <NUM> is removed from the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the intermediate boom <NUM>, the connection between the distal end boom <NUM> and the intermediate boom <NUM> is released, and the distal end boom <NUM> and the intermediate boom <NUM> are brought into a disconnection state.

The B pin <NUM> is inserted so as to be bridged over the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the proximal end boom <NUM>. As a result, the intermediate boom <NUM> and the proximal end boom <NUM> are connected to each other and brought into a connection state. Meanwhile, when the B pin <NUM> is removed from the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the proximal end boom <NUM>, the connection between the intermediate boom <NUM> and the proximal end boom <NUM> is released, and the intermediate boom <NUM> and the proximal end boom <NUM> are brought into a disconnection state.

The distal end boom <NUM> is not movable in the telescoping direction with respect to the intermediate boom <NUM> in the connection state in which the distal end boom <NUM> is connected to the intermediate boom <NUM> with the B pin <NUM>, and the distal end boom <NUM> is movable in the telescoping direction with respect to the intermediate boom <NUM> in the disconnection state. Similarly, the intermediate boom <NUM> is not movable in the telescoping direction with respect to the proximal end boom <NUM> in the connection state in which the intermediate boom <NUM> is connected to the proximal end boom <NUM> with the B pin <NUM>, and the intermediate boom <NUM> is movable in the telescoping direction with respect to the proximal end boom <NUM> in the disconnection state.

The C pin <NUM> is displaced in an axial direction thereof on the basis of the operation of a cylinder connection module <NUM> included in the pin insertion/removal actuator <NUM>.

Specifically, the distal end boom <NUM> and the intermediate boom <NUM> take either one of an engaged state in which the C pin <NUM> is engaged with the C pin receiving parts <NUM> and <NUM> and a disengaged state in which the C pin <NUM> is detached from the C pin receiving parts <NUM> and <NUM>.

In the engaged state, the distal end boom <NUM> and the intermediate boom <NUM> are movable in the telescoping direction together with a movable portion of the telescoping actuator <NUM> (cylinder part <NUM> in the present embodiment). When the intermediate boom <NUM> moves, the distal end boom <NUM> connected to the intermediate boom <NUM> via the B pin <NUM> also moves together in the telescoping direction.

The extending operation of the telescopic boom <NUM> will be briefly described as follows.

<FIG> illustrates a fully retracted state of the telescopic boom <NUM>. In this state, the distal end boom <NUM> is accommodated in the intermediate boom <NUM>, is connected to the intermediate boom <NUM> via the B pin <NUM>, and is not movable in an extending direction (see <FIG>). In addition, the C pin <NUM> is engaged with the C pin receiving part <NUM> of the distal end boom <NUM>, and the distal end boom <NUM> and the cylinder part <NUM> are in an engaged state.

As illustrated in <FIG>, the B pin <NUM> is removed from the proximal end side B pin receiving part <NUM> of the intermediate boom <NUM> (see a part surrounded by a broken line in <FIG>), the distal end boom <NUM> and the intermediate boom <NUM> are brought into the disconnection state, and the distal end boom <NUM> is movable in the extending direction.

As illustrated in <FIG>, the distal end boom <NUM> moves to the distal end side as the telescoping actuator <NUM> operates to move the cylinder part <NUM> in the extending direction.

As illustrated in <FIG>, after the distal end boom <NUM> moves to a predetermined position, the B pin <NUM> is inserted into the distal end side B pin receiving part <NUM> of the intermediate boom <NUM> (see a part surrounded by a broken line in <FIG>), the distal end boom <NUM> and the intermediate boom <NUM> are brought into the connection state, and the distal end boom <NUM> is not movable in the extending direction.

As illustrated in <FIG>, engagement between the C pin receiving part <NUM> of the distal end boom <NUM> and the C pin <NUM> is released (see a part surrounded by a broken line in <FIG>), and only the cylinder part <NUM> can be restored to a contracted state after being separated from the distal end boom <NUM>.

Then, as illustrated in <FIG>, the cylinder part <NUM> is restored to the contracted state, the C pin receiving part <NUM> of the intermediate boom <NUM> and the C pin <NUM> are engaged with each other, and the intermediate boom <NUM> and the cylinder part <NUM> are brought into an engaged state.

Note that in a case where the intermediate boom <NUM> is extended, operation similar to the operation described above is performed. In addition, in a case where the distal end boom <NUM> or the intermediate boom <NUM> is contracted, operation in a direction opposite to a direction described above is performed.

The extending operation and the contraction operation of the telescopic boom <NUM> described above are performed by the telescopic device A incorporated in the telescopic boom <NUM>. The telescopic device A is disposed in the internal space of the distal end boom <NUM> in the fully retracted state (state illustrated in <FIG>) of the telescopic boom <NUM>. A detailed configuration of the telescopic device A will be described below.

<FIG> is an external perspective view of the telescopic device A. Hereinafter, each component constituting the telescopic device A will be described using an orthogonal coordinate system (X, Y, Z) on the basis of a state in which each component is incorporated in the telescopic device A. Also in figures to be described later, each component is illustrated by the common orthogonal coordinate system (X, Y, Z). In the orthogonal coordinate system (X, Y, Z), an X direction coincides with the telescoping direction of the telescopic boom <NUM>. A + side in the X direction is the distal end side of the telescopic boom <NUM>, and a - side in the X direction is the proximal end side of the telescopic boom <NUM>. For example, a Z direction coincides with an up-and-down direction of the mobile crane <NUM> in a fallen state in which a derricking angle of the telescopic boom <NUM> is <NUM>°. A Y direction is orthogonal to the X direction and the Z direction and coincides with, for example, the width direction of the telescopic boom <NUM>.

As illustrated in <FIG>, the telescopic device A includes the telescoping actuator <NUM> and the pin insertion/removal actuator <NUM>. The pin insertion/removal actuator <NUM> is disposed, for example, on the proximal end side of the telescoping actuator <NUM> so that the pin insertion/removal actuator <NUM> is movable together with the cylinder part <NUM>.

The telescoping actuator <NUM> is a hydraulic cylinder having a piston rod part <NUM> (see <FIG> and the like) and the cylinder part <NUM>. The telescoping actuator <NUM> moves the boom element (for example, the distal end boom <NUM> or the intermediate boom <NUM>) connected to the cylinder part <NUM> via the C pin <NUM> (see <FIG> and the like) in the telescoping direction. The cylinder part <NUM> has, for example, a cylinder frame <NUM> with a rail. The rail (not illustrated) of the cylinder frame <NUM> is engaged with a rail groove provided in the telescopic boom <NUM>. As a result, the cylinder part <NUM> can slide along the telescopic boom <NUM> in a stable posture in the telescoping direction. Note that since a main structure of the telescoping actuator <NUM> is substantially similar to a main structure of a publicly known hydraulic cylinder, detailed description thereof will be omitted.

A configuration of the pin insertion/removal actuator <NUM> is illustrated in <FIG>. <FIG> are a perspective view of the pin insertion/removal actuator <NUM>, a plan view as viewed from a + side in the Z direction, and a side view as viewed from a + side in the Y direction, respectively. <FIG> are a perspective view of a state in which the pin insertion/removal actuator <NUM> and the B pin holding part <NUM> are engaged with each other and a front view seen from the - side in the X direction, respectively.

In <FIG>, a pair of the C pins <NUM> is distinguished as "C pins 150A and 150B". In addition, in <FIG>, the pair of B pins <NUM> is distinguished as "B pins 315A and 315B".

As illustrated in <FIG>, the pin insertion/removal actuator <NUM> is disposed on the - side in the X direction (proximal end side) of the cylinder part <NUM> and is configured to move in the telescoping direction together with the cylinder part <NUM>. The pin insertion/removal actuator <NUM> includes an electric motor <NUM> (electrical drive source), a brake <NUM>, a transmission mechanism <NUM>, a position detection device <NUM>, a lock mechanism <NUM> (see <FIG> and the like), the cylinder connection module <NUM> (first connecting device), and the boom connection module <NUM> (second connecting device). The transmission mechanism <NUM> includes a clutch <NUM>, a speed reducer <NUM>, and a torque limiter <NUM> (see <FIG>).

Each component is disposed in a housing <NUM> and unitized. As a result, it is possible to downsize the pin insertion/removal actuator <NUM>, improve productivity, and increase the reliability of a system. Specifically, the housing <NUM> has a box-shaped first housing <NUM> and a box-shaped second housing <NUM>.

The first housing <NUM> accommodates the cylinder connection module <NUM> in an internal space. Each of the C pins 150A and 150B of the cylinder connection module <NUM> is disposed so as to be movable forward and backward, for example, from both end parts of the first housing <NUM> in the Y direction. The piston rod part <NUM> (see <FIG> and the like) of the telescoping actuator <NUM> is inserted into the first housing <NUM> in the X direction. An end part of the cylinder part <NUM> is fixed to a side wall of the first housing <NUM> on the + side in the X direction.

The second housing <NUM> is provided on the + side in the Z direction of the first housing <NUM>. The second housing <NUM> accommodates the boom connection module <NUM> in an internal space. A B pin rack bar 220A of the boom connection module <NUM> is disposed so as to be movable forward and backward, for example, from one end part of the second housing <NUM> in the Y direction, and a B pin rack bar 220B is disposed so as to be movable forward and backward, for example, from the other end part. In addition, a transmission shaft <NUM> (see <FIG>) of the transmission mechanism <NUM> is inserted into the second housing <NUM> in the X direction.

The electric motor <NUM> is an electrical drive source that operates the cylinder connection module <NUM> and the boom connection module <NUM>. The electric motor <NUM> includes, for example, a rotary motor that uses electromagnetic force to output rotational motion.

As the rotary motor, for example, various electromagnetic motors such as a brush motor (direct current (DC) motor), a brushless DC motor, and a stepping motor can be applied. The operation of the electric motor <NUM> is controlled by a control device <NUM> (see <FIG>).

The electric motor <NUM> is supported by the second housing <NUM> via the transmission mechanism <NUM>. An output shaft (not illustrated) of the electric motor <NUM> extends in the X direction. For example, the electric motor <NUM> is disposed so that a ring gear (not illustrated) disposed on the outer periphery of the piston rod part <NUM> as a mechanical element of the transmission mechanism <NUM> meshes with the output shaft of the electric motor <NUM>. By disposing the electric motor <NUM> in this manner, it is possible to downsize the pin insertion/removal actuator <NUM> in the Y direction and the Z direction.

The electric motor <NUM> can be disposed in the cylinder frame <NUM> by applying a flat motor such as a large thin motor or a surface facing motor. In this case, a compact configuration is possible, and the cylinder frame <NUM> functions as a protective cover, so that the risk of damage due to interference during boom expansion/contraction operation can be reduced.

In addition, by taking advantage of a large outer diameter of the motor, power is directly transmitted from the output shaft of the electric motor <NUM> to the large-diameter ring gear, whereby a deceleration ratio can be reduced and inertia during insertion operation by a C pin biasing mechanism <NUM> or a B pin biasing mechanism <NUM> can be reduced.

The electric motor <NUM> is connected to, for example, a power supply device (not illustrated) disposed on the upper revolving body <NUM> (see <FIG>) via a power supply cable. In addition, the electric motor <NUM> is connected to, for example, the control device <NUM> disposed on the upper revolving body <NUM> via a control signal transmission cable. These cables can be paid out and wound by a cord reel provided at a proximal end part of the telescopic boom <NUM> or the upper revolving body <NUM> (see <FIG>).

Since the power supply cable and the control signal transmission cable requires a small wiring space and can be freely routed, the degree of freedom in design around the telescopic boom <NUM> is significantly improved as compared with a case where a pipe of a hydraulic actuator or a hydraulic circuit is provided.

In addition, the electric motor <NUM> has a manual operation part <NUM> that can be operated by a manual handle (not illustrated). The manual operation part <NUM> is for manually changing a state of the pin insertion/removal actuator <NUM> (specifically, the cylinder connection module <NUM> and the boom connection module <NUM>). The manual operation part <NUM> is turned with the manual handle when the electric motor <NUM> fails or the like, whereby the output shaft of the electric motor <NUM> rotates to change a state of the pin insertion/removal actuator <NUM>, and the B pins <NUM> and <NUM> and the C pin <NUM> can be inserted and removed.

In the present embodiment, the cylinder connection module <NUM> and the boom connection module <NUM> are operated by one electric motor <NUM>. Note that as the electric motor <NUM>, a motor for the cylinder connection module <NUM> and a motor for the boom connection module <NUM> may be separately provided. For example, in a case where the output shaft of the electric motor <NUM> is connected to a ring gear (not illustrated) of the transmission mechanism <NUM>, since the disposition of the electric motor <NUM> is not particularly limited as long as the electric motor <NUM> is disposed on the outer periphery of the ring gear, a plurality of small motors can be easily disposed as the electric motor <NUM>. In addition, since it is possible to obtain required torque by increasing or decreasing the number of the electric motors <NUM>, the electric motor <NUM> can be composed of one type of motors, and can be easily applicable to the design of other models.

The brake <NUM> applies braking force to the electric motor <NUM>. The brake <NUM> includes, for example, an electromagnetic brake that performs braking using electromagnetic force.

The operation of the brake <NUM> is controlled by the control device <NUM>.

The brake <NUM> restricts the rotation of the output shaft of the electric motor <NUM> in a stopped state (non-energized state) of the electric motor <NUM>. The brake <NUM> operates, for example, in a removed state of the cylinder connection module <NUM> or in a removed state of the boom connection module <NUM>. As a result, the removed states of the cylinder connection module <NUM> and the boom connection module <NUM> are maintained in the stopped state of the electric motor <NUM>. In addition, it is possible to achieve power saving and prevent the electric motor <NUM> from generating heat due to the electric motor <NUM> being brought into a locked state as compared with a case where the removed state is maintained by motor torque.

In addition, in a case where external force of a predetermined magnitude acts on the cylinder connection module <NUM> or the boom connection module <NUM> at the time of braking, the brake <NUM> may allow the rotation (that is, sliding) of the electric motor <NUM>. As a result, it is possible to prevent mechanical elements (for example, the electric motor <NUM>, gears, and the like) of the pin insertion/removal actuator <NUM> from being damaged by overload.

The brake <NUM> is preferably disposed in a stage preceding the speed reducer <NUM> of the transmission mechanism <NUM>. The stage preceding is an upstream side (-side in the X direction) in a power transmission path through which the power of the electric motor <NUM> is transmitted to the cylinder connection module <NUM> or the boom connection module <NUM>, and the stage preceding includes an upstream side of the electric motor <NUM>. Meanwhile, a stage following is a downstream side (+ side in the X direction) in the power transmission path of the electric motor <NUM>. In the present embodiment, the brake <NUM> is disposed coaxially with the electric motor <NUM> on the - side in the X direction of the electric motor <NUM> (that is, a side opposite to the transmission mechanism <NUM> with the electric motor <NUM> as the center). By disposing the brake <NUM> in this manner, it is possible to downsize the pin insertion/removal actuator <NUM> in the Y direction and the Z direction. In addition, in a case where the brake <NUM> is disposed in the stage preceding the speed reducer <NUM>, since brake torque required for maintaining the stopped state of the electric motor <NUM> is smaller than that in a case where the brake <NUM> is disposed in a stage following the speed reducer <NUM>, it is possible to downsize the brake <NUM>.

Note that various brake devices such as a mechanical brake device and an electromagnetic brake device can be applied to the brake <NUM>. In addition, the position of the brake <NUM> is not limited to a position in the present embodiment.

The transmission mechanism <NUM> transmits the power (that is, rotational motion) of the electric motor <NUM> to the cylinder connection module <NUM> and the boom connection module <NUM>.

The transmission mechanism <NUM> is disposed in the second housing <NUM>. The transmission mechanism <NUM> has the clutch <NUM>, the speed reducer <NUM>, the torque limiter <NUM>, and the like (see <FIG>). The transmission mechanism <NUM> has, for example, the ring gear (not illustrated) disposed on the outer periphery of the piston rod part <NUM> and a transmission gear meshing with the ring gear, and the clutch <NUM>, the speed reducer <NUM>, and the torque limiter <NUM> are disposed on the transmission shaft <NUM> connected to the transmission gear.

The clutch <NUM> is disposed in the power transmission path for transmitting the power of the electric motor <NUM> and discretionally intermittently transmits the power to the cylinder connection module <NUM> and the boom connection module <NUM>. The clutch <NUM> is disposed, for example, in the stage preceding the speed reducer <NUM> (between the electric motor <NUM> and the speed reducer <NUM> in the present embodiment) in the power transmission path. By disposing the clutch <NUM> in this manner, it is possible to reduce a transmission torque capacity of the clutch <NUM> and downsize the clutch <NUM>.

For example, an electromagnetic clutch, a mechanical clutch, or a torque diode can be applied to the clutch <NUM>. Since these configurations are publicly known, the configurations will be briefly described.

The electromagnetic clutch is a mechanical element that electromagnetically transmits or cuts off power transmission from an input shaft to an output shaft. In a case where the electromagnetic clutch is applied, the operation of the clutch <NUM> is controlled, for example, by the control device <NUM>. Note that in a case where the operation of the clutch <NUM> is interlocked with the electric motor <NUM>, it is not necessary to individually control the clutch <NUM>.

The mechanical clutch is a mechanical element that transmits power by engagement between the input shaft and the output shaft. In a case where the mechanical clutch is applied, the clutch <NUM> is preferably a one-way clutch that transmits power from an input shaft to an output shaft while cutting off power from the output shaft to the input shaft and transmits power only in one direction.

The torque diode is a mechanical element that transmits power from an input shaft to an output shaft while cutting off power from the output shaft to the input shaft.

In a case where the mechanical clutch and the torque diode are applied, electrical control by the control device <NUM> or the like is unnecessary.

The speed reducer <NUM> decelerates the rotation of the electric motor <NUM> and outputs the decelerated rotation. The speed reducer <NUM> includes, for example, a planetary gear mechanism accommodated in a speed reducer case (reference sign is omitted), and an input shaft and an output shaft extend in the X direction. By disposing the speed reducer <NUM> in this manner, it is possible to downsize the pin insertion/removal actuator <NUM> in the Y direction and the Z direction.

The torque limiter <NUM> is an overload protection device that is disposed in the power transmission path for transmitting the power of the electric motor <NUM> and maintains torque acting on mechanical elements (for example, the electric motor <NUM>) constituting the power transmission path at a predetermined value or less. The torque limiter <NUM> is disposed, for example, in a stage following the speed reducer <NUM> in the power transmission path. By disposing the torque limiter <NUM> in this manner, it is possible to reduce influence of tolerances and variations of a torque setting value as compared with a case where the torque limiter <NUM> is disposed in the stage preceding the speed reducer <NUM>. In addition, for example, the torque limiter <NUM> may be disposed in the stage preceding the speed reducer <NUM> in the power transmission path. In this case, since the torque setting value is decreased, it is possible to downsize the torque limiter <NUM>.

Note that the torque limiter <NUM> continues to slide while the electric motor <NUM> is driven, whereby predetermined torque can continue to be given to the cylinder connection module <NUM> and the boom connection module <NUM>. Therefore, the torque limiter <NUM> can be used as a substitute for the brake <NUM> to maintain the removed states of the cylinder connection module <NUM> and the boom connection module <NUM>. In addition, since the electric motor <NUM> is not brought into the locked state, heat generation due to overload does not occur.

The torque limiter <NUM> includes, for example, a friction torque limiter that is attached to an output shaft of the clutch <NUM> (transmission shaft <NUM> of the transmission mechanism <NUM>) and in which an input side element and an output side element are joined together while sliding when torque larger than a predetermined value is generated.

The position detection device <NUM> detects the displacement of the C pin <NUM> and the B pins <NUM> and <NUM> on the basis of the output (for example, the rotation of the output shaft) of the electric motor <NUM>. The position detection device <NUM> detects, for example, a moving direction (rotation direction) and a moving amount (rotation angle) from a reference position of the C pin <NUM> or each of the B pins <NUM> and <NUM> (see <FIG> and <FIG>).

The position detection device <NUM> includes, 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 a rotation amount of the output shaft of the electric motor <NUM>. The rotary encoder detects and outputs the rotational displacement of the input shaft using a built-in lattice disk. The potentiometer converts a change in the rotation angle into a change in a resistance value and outputs the change in the resistance value.

An output method of the rotary encoder is not particularly limited and may be an incremental method of outputting a pulse signal (relative angle signal) according to a rotation amount (rotation angle) from a measurement start position, or an absolute method of outputting a code signal (absolute angle signal) corresponding to an absolute angle position with respect to a reference point.

In a case where the position detection device <NUM> includes an absolute type rotary encoder, absolute positions of the C pin <NUM> and the B pins <NUM> and <NUM> can be detected even when the non-energized state is restored to an energized state.

The position detection device <NUM> may be provided directly on the output shaft of the electric motor <NUM> or may be provided on a rotating member (for example, a rotation shaft, a gear, or the like) that rotates together with the output shaft of the electric motor <NUM>.

In the present embodiment, the position detection device <NUM> is provided on the transmission shaft <NUM> in a stage following (on the + side in the X direction of) the transmission mechanism <NUM> (torque limiter <NUM>) and outputs information corresponding to a rotation amount of the transmission shaft <NUM>. In this case, a rotary encoder capable of obtaining sufficient resolution with respect to the number of rotations (rotation speed) of the transmission shaft <NUM> is suitable for the position detection device <NUM>.

Note that since a C pin toothless gear <NUM> of the cylinder connection module <NUM> and a B pin toothless gear <NUM> of the boom connection module <NUM> are fixed to the transmission shaft <NUM>, a detection result of the position detection device <NUM> can also be said to be information corresponding to rotation amounts of the C pin toothless gear <NUM> and the B pin toothless gear <NUM>.

Note that the position detection device <NUM> is not limited to the above-described rotary encoder and may include, for example, a limit switch or a proximity sensor. The limit switch is disposed in the stage following the speed reducer <NUM> and mechanically operates on the basis of the output of the electric motor <NUM>. In addition, the proximity sensor is disposed in the stage following the speed reducer <NUM> so that the proximity sensor faces the rotating member that rotates on the basis of the output of the electric motor <NUM>, and the proximity sensor outputs a detection signal on the basis of a distance from the rotating member described above. The detection result of the position detection device <NUM> is output to the control device <NUM>.

However, the proximity sensor and the limit switch are provided, for example, at positions where an inserted state and a removed state of each of the C pin <NUM> and the B pins <NUM> and <NUM> can be detected, and at least as many proximity sensors and limit switches as the C pin <NUM> and the B pin rack bars 220A and 220B are required. In contrast to this, in a case where the rotary encoder is applied, since a state of each of the C pin <NUM> and the B pins <NUM> and <NUM> can be detected by one detection sensor, it is possible to reduce the number of parts, and it is possible to reduce a cost.

In addition, the disposition of the position detection device <NUM> is not limited to the present embodiment. For example, the position detection device <NUM> may be disposed in the stage preceding the speed reducer <NUM>. That is, the position detection device <NUM> may acquire information to be output to the control device <NUM> on the basis of the rotation of the electric motor <NUM> before being decelerated by the speed reducer <NUM>. In a case where the position detection device <NUM> is disposed in the stage preceding the speed reducer <NUM>, high resolution can be obtained as compared with a case where the position detection device is disposed in the stage following the speed reducer <NUM>.

The control device <NUM> is, for example, an in-vehicle computer having a central processing unit (CPU) as an arithmetic/control device, a read only memory (ROM) and a random access memory (RAM) as main storage devices, an input terminal, an output terminal, and the like. The control device <NUM> calculates information on a position of the C pin <NUM> or positions of the B pins <NUM> and <NUM> on the basis of the output of the position detection device <NUM>. In the calculation, data (tables, maps, and the like) indicating a correlation between the output of the position detection device <NUM> and the information on the positions of the C pin <NUM> and the B pins <NUM> and <NUM> (for example, the moving amount from the reference position) is used. This data is stored, for example, in the ROM.

For example, the control device <NUM> determines whether the C pin <NUM> is in the engaged state (for example, in a state illustrated in <FIG>) or in the disengaged state (for example, in a state illustrated in <FIG>) with respect to the C pin receiving part <NUM> of the distal end boom <NUM> or the C pin receiving part <NUM> of the intermediate boom <NUM>, that is, a connection state between the pin insertion/removal actuator <NUM> and the distal end boom <NUM> or the intermediate boom <NUM>, by calculation on the basis of the output of the position detection device <NUM>.

In addition, in a case where an object to be telescoped is the distal end boom <NUM>, the control device <NUM> determines whether the B pin <NUM> of the distal end boom <NUM> and the intermediate boom <NUM> are in the engaged state (see <FIG>, and the like) or in the disengaged state (see <FIG>), that is, the connection state between the distal end boom <NUM> and the intermediate boom <NUM> by calculation on the basis of the detection result of the position detection device <NUM>. Similarly, in a case where an object to be telescoped is the intermediate boom <NUM>, the control device <NUM> determines the connection state between the intermediate boom <NUM> and the proximal end boom <NUM> by calculation on the basis of the detection result of the position detection device <NUM>.

The control device <NUM> executes various types of control of the pin insertion/removal actuator <NUM>, including, for example, operation control of the electric motor <NUM>, the brake <NUM>, the clutch <NUM>, and the like on the basis of a calculation result. Note that, in executing the various types of control of the pin insertion/removal actuator <NUM>, for example, various sensors provided in the telescopic boom <NUM> or the telescoping actuator <NUM> may be used to acquire information indicating a state of the telescopic boom <NUM> or the telescoping actuator <NUM>.

Referring to <FIG>, the cylinder connection module <NUM> and the boom connection module <NUM> will be described. <FIG> are views illustrating an internal structure of the pin insertion/removal actuator <NUM>. <FIG> is a view schematically illustrating the configuration of the pin insertion/removal actuator <NUM>.

<FIG> illustrate a neutral state in which the electric motor <NUM> is in the stopped state and the cylinder connection module <NUM> and the boom connection module <NUM> are not operating. In the neutral state, both the cylinder connection module <NUM> and the boom connection module <NUM> are in an inserted state. The neutral state is maintained, for example, by the movement of the C pin rack bar <NUM> and the B pin rack bars 220A and 220B being mechanically restricted by a stopper (not illustrated). Note that the neutral state may be maintained by the biasing force of the C pin biasing mechanism <NUM> and the biasing force of the B pin biasing mechanism <NUM> being balanced with each other.

In addition, <FIG> illustrate the removed state of the boom connection module <NUM> and the removed state of the cylinder connection module <NUM>. As illustrated in <FIG>, in the removed state of the cylinder connection module <NUM>, the boom connection module <NUM> is maintained in the inserted state. As illustrated in <FIG>, in the removed state of the boom connection module <NUM>, the cylinder connection module <NUM> is maintained in the inserted state.

The cylinder connection module <NUM> operates on the basis of the power (that is, rotational motion) of the electric motor <NUM> and changes between the inserted state (see <FIG>) and the removed state (see <FIG>).

The inserted state of the cylinder connection module <NUM> is a state in which the C pin receiving part <NUM> of the distal end boom <NUM> or the C pin receiving part <NUM> of the intermediate boom <NUM> are engaged with the C pin <NUM> to connect the respective boom elements and the pin insertion/removal actuator <NUM>. In this connection state, the distal end boom <NUM> and the intermediate boom <NUM> are movable together with the cylinder part <NUM> and the pin insertion/removal actuator <NUM> (see <FIG>, <FIG>, and the like).

Meanwhile, the removed state of the cylinder connection module <NUM> is a state in which the C pin <NUM> is detached from the C pin receiving parts <NUM> and <NUM> of the distal end boom <NUM> or the intermediate boom <NUM>, and the respective boom elements are separated from the pin insertion/removal actuator <NUM>. In this disconnection state, the cylinder part <NUM> and the pin insertion/removal actuator <NUM> are movable independently from the respective boom elements (see <FIG>, <FIG>, and the like).

The boom connection module <NUM> operates on the basis of the power (that is, rotational motion) of the electric motor <NUM> and changes between the inserted state (see <FIG>) and the removed state (see <FIG>).

The inserted state of the boom connection module <NUM> is, for example, a state in which the B pin <NUM> is inserted into the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the intermediate boom <NUM> to connect the distal end boom <NUM> and the intermediate boom <NUM>. In this connection state, the distal end boom <NUM> is not movable in the telescoping direction with respect to the intermediate boom <NUM> (see <FIG>, <FIG>, and the like).

Meanwhile, the removed state of the boom connection module <NUM> is, for example, a state in which the B pin <NUM> is detached from the proximal end side B pin receiving part <NUM> or the distal end side B pin receiving part <NUM> of the intermediate boom <NUM>, and the distal end boom <NUM> is separate from the intermediate boom <NUM>.

In this disconnection state, the distal end boom <NUM> is movable in the telescoping direction with respect to the intermediate boom <NUM> (see <FIG>, <FIG>, and the like).

As illustrated in <FIG>, the cylinder connection module <NUM> has the C pin toothless gear <NUM>, the C pin rack bar <NUM>, a first gear group <NUM>, a second gear group <NUM>, the C pin <NUM>, and the C pin biasing mechanism <NUM>. Each of the mechanical elements <NUM> to <NUM> is an example of constituent members of the first connection mechanism. In the following description, the C pin <NUM> is distinguished as the "C pins 150A and 150B".

Note that in the present embodiment, a pair of the C pins 150A and 150B is incorporated in the cylinder connection module <NUM>, but the C pins 150A and 150B may be provided independently from the cylinder connection module <NUM>.

The C pin toothless gear <NUM> is a substantially discoid gear and has a tooth part <NUM> (see <FIG>) on a part of the outer peripheral surface. The C pin toothless gear <NUM> is externally fitted and fixed to the transmission shaft <NUM> of the transmission mechanism <NUM> and rotates together with the transmission shaft <NUM>. The C pin toothless gear <NUM> constitutes a switch gear G (see <FIG>) together with the B pin toothless gear <NUM> of the boom connection module <NUM>. The power of the electric motor <NUM> is alternatively transmitted to either one of the cylinder connection module <NUM> and the boom connection module <NUM> by the switch gear G.

In the present embodiment, the C pin toothless gear <NUM> and the B pin toothless gear <NUM> constituting the switch gear G are incorporated in the cylinder connection module <NUM> that is the first connection mechanism and the boom connection module <NUM> that is the second connection mechanism, respectively. However, the switch gear G may be provided independently from the first connection mechanism and the second connection mechanism.

In addition, the switch gear G only needs to function as the C pin toothless gear <NUM> and the B pin toothless gear <NUM> and for example, may include one toothless gear, as illustrated in <FIG>.

In the following description, a rotation direction (R1 direction in <FIG>) of the C pin toothless gear <NUM> when the cylinder connection module <NUM> changes from the inserted state (see <FIG>) to the removed state (see <FIG>) is referred to as the "forward direction", and a rotation direction (R2 direction in <FIG>) of the C pin toothless gear <NUM> when the cylinder connection module <NUM> changes from the removed state to the inserted state is referred to as the "reverse direction".

Among projections constituting the tooth part <NUM> of the C pin toothless gear <NUM>, a projection provided at an end part in the forward direction of the C pin toothless gear <NUM> is a positioning tooth (not illustrated).

The C pin rack bar <NUM> is, for example, a shaft member extending in one direction and is disposed along the Y direction on a lower side (- side in the Z direction) of the C pin toothless gear <NUM>.

The C pin rack bar <NUM> has an input side rack part <NUM> on a surface closer to the C pin toothless gear <NUM> ( + side in the Z direction) and has two output side rack parts <NUM> and <NUM> on a surface farther from the C pin toothless gear <NUM> (- side in the Z direction).

The input side rack part <NUM> meshes with the tooth part <NUM> of the C pin toothless gear <NUM> only when the cylinder connection module <NUM> changes from the inserted state (see <FIG>) to the removed state (see <FIG>).

Specifically, in the inserted state of the cylinder connection module <NUM>, a first end face (not illustrated) of the input side rack part <NUM> on the + side in the Y direction abuts on the positioning tooth (not illustrated) in the tooth part <NUM> of the C pin toothless gear <NUM> or faces the positioning teeth (not illustrated) in the Y direction via a slight gap. In this state, when the C pin toothless gear <NUM> rotates in the R1 direction, the positioning tooth pushes the first end face to the + side in the Y direction, and the C pin rack bar <NUM> moves to the + side in the Y direction. Then, the tooth part <NUM> formed in the reverse direction from the positioning tooth sequentially mesh with the input side rack part <NUM>. As a result, the C pin rack bar <NUM> moves to the + side in the Y direction along with the rotation of the C pin toothless gear <NUM> in the R1 direction.

Note that in a case where the C pin toothless gear <NUM> rotates in the R2 direction in the inserted state of the cylinder connection module <NUM> illustrated in <FIG>, the input side rack part <NUM> does not mesh with the tooth part <NUM> of the C pin toothless gear <NUM>.

As described above, the C pin rack bar <NUM> moves in a longitudinal direction (Y direction) thereof with the rotation of the C pin toothless gear <NUM>. The C pin rack bar <NUM> is positioned on the most - side in the Y direction in the inserted state of the cylinder connection module <NUM> (see <FIG>) and is positioned on the most + side in the Y direction in the removed state (see <FIG>).

That is, when the C pin toothless gear <NUM> rotates in the R1 direction in the inserted state (neutral state) of the cylinder connection module <NUM>, the C pin rack bar <NUM> moves to the + side in the Y direction and changes to the removed state. Meanwhile, when the C pin toothless gear <NUM> rotates in the R2 direction in the removed state of the cylinder connection module <NUM>, the C pin rack bar <NUM> moves to the - side in the Y direction and changes to an inserted state.

The output side rack parts <NUM> and <NUM> mesh with the first gear group <NUM> and the second gear group <NUM>, respectively.

The first gear group <NUM> has, for example, a drive gear <NUM>, an intermediate gear <NUM>, and a driven gear <NUM>. Each gear element includes a spur gear.

Specifically, the drive gear <NUM> meshes with the output side rack part <NUM> of the C pin rack bar <NUM> and the intermediate gear <NUM>. The intermediate gear <NUM> meshes with the drive gear <NUM> and the driven gear <NUM>. The driven gear <NUM> meshes with the intermediate gear <NUM> and a pin side rack part <NUM> of one C pin 150A.

When the cylinder connection module <NUM> is in the inserted state, the drive gear <NUM> meshes with an end part on the + side in the Y direction or a part close to the end part in the output side rack part <NUM> of the C pin rack bar <NUM>. In addition, the driven gear <NUM> meshes with the end part on the - side in the Y direction of the pin side rack part <NUM> of the one C pin 150A.

The second gear group <NUM> has, for example, a drive gear <NUM> and a driven gear <NUM>. Each gear element includes a spur gear.

Specifically, the drive gear <NUM> meshes with an output side rack part <NUM> of the C pin rack bar <NUM> and the driven gear <NUM>. The driven gear <NUM> meshes with the drive gear <NUM> and the pin side rack part <NUM> of the other C pin 150B.

When the cylinder connection module <NUM> is in the inserted state, the drive gear <NUM> meshes with an end part on the + side in the Y direction or a part close to the end part in the output side rack part <NUM> of the C pin rack bar <NUM>. In addition, the driven gear <NUM> meshes with the end on the + side in the Y direction in the pin side rack part <NUM> of the other C pin 150B.

In the first gear group <NUM>, the drive gear <NUM> and the driven gear <NUM> are connected via the intermediate gear <NUM>, whereas in the second gear group <NUM>, the drive gear <NUM> and the driven gear <NUM> are directly connected. Therefore, a rotation direction of the driven gear <NUM> of the first gear group <NUM> and a rotation direction of the driven gear <NUM> of the second gear group <NUM> are opposite to each other.

The pair of C pins 150A and 150B is disposed, for example, coaxially with each other in the Y direction. The C pins 150A and 150B are preferably symmetric with respect to the center of the piston rod part <NUM> of the telescoping actuator <NUM>. As a result, it is possible to prevent bending stress from being generated in the piston rod part <NUM> and to reduce a dimension in a height direction (Z direction).

Note that the C pins 150A and 150B only need to be disposed symmetrically with respect to the telescoping direction (X direction), and for example, may be disposed at positions shifted from each other in the Z direction or may be provided at positions eccentric to the piston rod part <NUM> (for example, the - side in the Z direction of the piston rod part <NUM>).

Hereinafter, distal end parts of the C pins 150A and 150B are end parts on sides far from each other, and proximal end parts thereof are end parts on sides close to each other.

The C pins 150A and 150B each have a pin side rack part <NUM> on the outer peripheral surface.

The pin side rack part <NUM> of the one C pin 150A meshes with the driven gear <NUM> of the first gear group <NUM>. The pin side rack part <NUM> of the other C pin 150B meshes with the driven gear <NUM> of the second gear group <NUM>.

The C pins 150A and 150B move in an axial direction thereof (Y direction) with the rotation of the driven gears <NUM> and <NUM>, respectively. Specifically, the one C pin 150A moves to the - side in the Y direction when the cylinder connection module <NUM> changes from the inserted state to the removed state, and the one C pin 150A moves to the + side in the Y direction when the cylinder connection module <NUM> changes from the removed state to the inserted state. The other C pin 150B moves to the + side in the Y direction when the cylinder connection module <NUM> changes from the inserted state to the removed state, and the other C pin 150B moves to the - side in the Y direction when the cylinder connection module <NUM> changes from the removed state to the inserted state. That is, in the above-described state change, the C pins 150A and 150B move in directions opposite to each other in the Y direction.

The C pin biasing mechanism <NUM> biases the C pins 150A and 150B in directions away from each other. The C pin biasing mechanism <NUM> includes, for example, a pair of compression coil springs. In the present embodiment, the C pin biasing mechanism <NUM> is disposed on each of the proximal end sides of the C pins 150A and 150B and biases the C pins 150A and 150B toward the distal end side.

When the electric motor <NUM> rotates in the R1 direction to bring the cylinder connection module <NUM> into the removed state (see <FIG>) and then the operation of the electric motor <NUM> stops, the cylinder connection module <NUM> is automatically restored to the inserted state by the biasing force of the C pin biasing mechanism <NUM>. However, in a case where the brake <NUM> is operating, the cylinder connection module <NUM> is not automatically restored to the inserted state, and the removed state is maintained.

Note that the C pin biasing mechanism <NUM> may directly apply biasing force to the C pins 150A and 150B or may apply biasing force via another member. In addition, the C pin biasing mechanism <NUM> may be omitted, and the cylinder connection module <NUM> may be configured to change from the removed state to the inserted state on the basis of the power of the electric motor <NUM>. Even in this case, from the viewpoint of fail-safe, it is preferable to provide the C pin biasing mechanism <NUM> and configure so that the cylinder connection module <NUM> is restored to the inserted state that is a safe side when the electric motor <NUM> fails.

As illustrated in <FIG>, the boom connection module <NUM> has the B pin toothless gear <NUM>, a pair of the B pin rack bars 220A and 220B, a synchronous gear <NUM> (see <FIG>), and the B pin biasing mechanism <NUM>. Each of the mechanical elements <NUM> to <NUM> is an example of constituent members of the second connection mechanism. In the following description, the B pin <NUM> is distinguished as the "B pins 315A and 315B".

In addition, a case where the boom connection module <NUM> acts on the B pin <NUM> will be described, but the same applies to a case where the boom connection module <NUM> acts on the B pin <NUM>.

The B pin toothless gear <NUM> is a substantially discoid gear and has a tooth part <NUM> on a part of the outer peripheral surface. The B pin toothless gear <NUM> is externally fitted and fixed to the transmission shaft <NUM> on the + side in the X direction of the C pin toothless gear <NUM> and rotates together with the transmission shaft <NUM>. As described above, the B pin toothless gear <NUM> constitutes the switch gear G (see <FIG>) together with the C pin toothless gear <NUM> of the cylinder connection module <NUM>.

In the following description, a rotation direction (R2 direction in <FIG>) of the B pin toothless gear <NUM> when the boom connection module <NUM> changes from the inserted state (see <FIG>) to the removed state (see <FIG>) is referred to as the "forward direction", and a rotation direction (R1 direction in <FIG>) of the B pin toothless gear <NUM> when the boom connection module <NUM> changes from the removed state to the inserted state is referred to as the "reverse direction".

Among projections constituting the tooth part <NUM> of the B pin toothless gear <NUM>, a projection provided at an end part in the forward direction of the B pin toothless gear <NUM> is a positioning tooth (reference sign is omitted).

That is, the rotation direction R2 of the B pin toothless gear <NUM> when the boom connection module <NUM> changes from the inserted state to the removed state is opposite to the rotation direction R1 of the C pin toothless gear <NUM> when the cylinder connection module <NUM> changes from the inserted state to the removed state.

The pair of B pin rack bars 220A and 220B is, for example, shaft members extending in one direction and is disposed parallel to each other along the Y direction on an upper side ( + side in the Z direction) of the B pin toothless gear <NUM>. In addition, the B pin rack bars 220A and 220B are disposed around the synchronous gear <NUM> (see <FIG>) in the X direction.

Each of the B pin rack bars 220A and 220B has an engaging part <NUM> that engages with a locking piece 314a of the B pin holding part <NUM>. The locking piece 314a is provided, for example, at both end parts in the Y direction (in the vicinity of the B pins 315A and 315B) in the B pin holding part <NUM>.

One B pin rack bar 220B has a drive side rack part <NUM> on a surface close to the B pin toothless gear <NUM>. In addition, the B pin rack bars 220A and 220B have synchronization side rack parts <NUM> (see <FIG>) on surfaces facing each other in the X direction. Each of the synchronization side rack parts <NUM> meshes with the synchronous gear <NUM>.

The drive side rack part <NUM> meshes with the tooth part <NUM> of the B pin toothless gear <NUM> only when the boom connection module <NUM> changes from the inserted state (see <FIG>) to the removed state (see <FIG>).

Specifically, in the inserted state of the boom connection module <NUM>, a first end face (not illustrated) of the drive side rack part <NUM> on the + side in the Y direction abuts on the positioning tooth (not illustrated) in the tooth part <NUM> of the B pin toothless gear <NUM> or faces the positioning teeth (not illustrated) in the Y direction via a slight gap. In this state, when the B pin toothless gear <NUM> rotates in the R2 direction, the positioning tooth pushes the first end face to the + side in the Y direction, and the one B pin rack bar 220B moves to the + side in the Y direction.

In addition, when the one B pin rack bar 220B moves to the + side in the Y direction, the synchronous gear <NUM> rotates, and the other B pin rack bar 220A moves to the - side in the Y direction (that is, a side opposite to the B pin rack bar 220B).

Note that in a case where the B pin toothless gear <NUM> rotates in the R1 direction in the inserted state of the boom connection module <NUM> illustrated in <FIG>, the drive side rack part <NUM> does not mesh with the tooth part <NUM> of the B pin toothless gear <NUM>.

As described above, each of the B pin rack bars 220A and 220B moves in a longitudinal direction (Y direction) thereof with the rotation of the B pin toothless gear <NUM>. The one B pin rack bar 220B is positioned on the most - side in the Y direction in the inserted state of the boom connection module <NUM> (see <FIG>) and is positioned on the most + side in the Y direction in the removed state (see <FIG>). In addition, the other B pin rack bar 220A is positioned on the most + side in the Y direction in the inserted state of the boom connection module <NUM> (see <FIG>) and is positioned on the most - side in the Y direction in the removed state (see <FIG>).

As the one B pin rack bar 220B moves in the Y direction, one locking piece 314a of the B pin holding part <NUM> and the engaging part <NUM> of the B pin rack bar 220B abut on each other. Then, a member of the B pin holding part <NUM> that supports the B pin 315B moves in the Y direction, whereby the B pin 315B changes to an inserted state or a removed state.

Similarly, as the other B pin rack bar 220A moves in the Y direction, the other locking piece 314a of the B pin holding part <NUM> and the engaging part <NUM> of the B pin rack bar 220A abut on each other. Then, a member of the B pin holding part <NUM> that supports the B pin 315A moves in the Y direction, whereby the B pin 315A changes to an inserted state or a removed state.

In the above-described state change, the B pins 315A and 315B move in directions opposite to each other in the Y direction.

Note that the movement of the one B pin rack bar 220B toward the + side in the Y direction and the movement of the other B pin rack bar 220A toward the - side in the Y direction are restricted, for example, by abutment on a stopper (not illustrated) provided in the housing <NUM>.

The B pin biasing mechanism <NUM> biases the B pin rack bars 220A and 220B in directions away from each other. The B pin biasing mechanism <NUM> includes, for example, a pair of compression coil springs. In the present embodiment, the B pin biasing mechanism <NUM> is incorporated in the B pin rack bars 220A and 220B and biases the B pin rack bars 220A and 220B toward the distal end side.

When the electric motor <NUM> rotates in the R2 direction to bring the boom connection module <NUM> into the removed state (see <FIG>) and then the operation of the electric motor <NUM> stops, the boom connection module <NUM> is automatically restored to the inserted state (see <FIG>) by the biasing force of the B pin biasing mechanism <NUM>. However, in a case where the brake <NUM> is operating, the boom connection module <NUM> is not automatically restored to the inserted state, and the removed state is maintained.

Note that the B pin biasing mechanism <NUM> may directly apply biasing force to the B pin rack bars 220A and 220B or may apply biasing force via another member. In addition, the B pin biasing mechanism <NUM> may be omitted, and the boom connection module <NUM> may be configured to change from the removed state to the inserted state on the basis of the power of the electric motor <NUM>. Even in this case, from the viewpoint of fail-safe, it is preferable to provide the B pin biasing mechanism <NUM> and configure so that the boom connection module <NUM> is restored to the inserted state that is a safe side when the electric motor <NUM> fails.

The lock mechanism <NUM> prevents external force other than power from the electric motor <NUM> from acting on the cylinder connection module <NUM> (for example, the C pin rack bar <NUM>) or the boom connection module <NUM> (for example, the B pin rack bars 220A and 220B) to cause the cylinder connection module <NUM> and the boom connection module <NUM> to change to the removed state simultaneously. That is, in a state in which one connection mechanism of the boom connection module <NUM> and the cylinder connection module <NUM> is operating, the lock mechanism <NUM> blocks the operation of the other connection mechanism.

Referring to <FIG>, the lock mechanism <NUM> will be described. <FIG> illustrates a state in which the cylinder connection module <NUM> and the boom connection module <NUM> are in the inserted state (neutral position), and <FIG> each illustrate a state when the boom connection module <NUM> changes from the inserted state to the removed state. Note that in <FIG>, the C pin toothless gear <NUM> of the cylinder connection module <NUM> and the B pin toothless gear <NUM> of the boom connection module <NUM> are illustrated as an integrally formed switch gear G.

As illustrated in <FIG> and the like, the lock mechanism <NUM> has a first projection <NUM>, a second projection <NUM>, and a cam member <NUM> (lock side rotating member).

The first projection <NUM> is provided integrally with the C pin rack bar <NUM> of the cylinder connection module <NUM>. Specifically, the first projection <NUM> is provided at a position adjacent to the input side rack part <NUM> of the C pin rack bar <NUM>.

The second projection <NUM> is provided integrally with the one B pin rack bar 220B of the boom connection module <NUM>. Specifically, the second projection <NUM> is provided at a position adjacent to the drive side rack part <NUM> of the one B pin rack bar 220B.

The cam member <NUM> is a plate-shaped member having a substantially crescent shape. The cam member <NUM> has a first cam receiving part 553a at one end in a circumferential direction and a second cam receiving part 553b at the other end.

For example, the cam member <NUM> is externally fitted and fixed to the transmission shaft <NUM> at a position shifted in the X direction from a position where the switch gear G is externally fitted and fixed. Note that in the present embodiment, the cam member <NUM> is externally fitted and fixed between the C pin toothless gear <NUM> and the B pin toothless gear <NUM>. That is, the cam member <NUM> is provided coaxially with the switch gear G and rotates around the transmission shaft <NUM> as a central axis together with the switch gear G with the rotation of the transmission shaft <NUM>.

Note that the cam member <NUM> may be provided integrally with the switch gear G. In addition, the cam member <NUM> may be provided integrally with at least one of the C pin toothless gear <NUM> and the B pin toothless gear <NUM>.

As illustrated in <FIG>, in a state in which a tooth part G1 of the switch gear G meshes with the drive side rack part <NUM> of the B pin rack bar 220B, the first cam receiving part 553a of the cam member <NUM> is positioned on the + side in the Y direction from the first projection <NUM>.

That is, the first cam receiving part 553a and the first projection <NUM> face each other via a slight gap in the Y direction. In this state, even if external force (external force Fa in <FIG>) acts on the C pin rack bar <NUM> toward the + side in the Y direction, the external force is absorbed by the gap.

When larger external force Fa is applied to the C pin rack bar <NUM> toward the + side in the Y direction, the C pin rack bar <NUM> moves from a position illustrated by a two-dot chain line in <FIG> to a position illustrated by a solid line. In this state, the first projection <NUM> abuts on the first cam receiving part 553a, and the movement of the C pin rack bar <NUM> toward the + side in the Y direction is prevented.

In addition, as illustrated in <FIG>, in a state in which the tooth part G1 of the switch gear G meshes with the input side rack part <NUM> of the C pin rack bar <NUM>, the second cam receiving part 553b of the cam member <NUM> is positioned on the + side in the Y direction of the second projection <NUM>. That is, the second cam receiving part 553b and the second projection <NUM> face each other via a slight gap in the Y direction. In this state, even if external force on the + side in the Y direction (external force Fb in <FIG>) is applied to the B pin rack bar 220B, the external force is absorbed by the gap.

When larger external force Fb is applied to the B pin rack bar 220B toward the + side in the Y direction, the B pin rack bar 220B moves from a position illustrated by a two-dot chain line in <FIG> to a position illustrated by a solid line in the + side in the Y direction. In this state, the second projection <NUM> abuts on the second cam receiving part 553b, and the movement of the B pin rack bar 220B toward the + side in the Y direction is prevented.

Referring to <FIG> and <FIG>, an example of operation of the cylinder connection module <NUM> and the boom connection module <NUM> will be described. The operation illustrated in <FIG> and <FIG> is, for example, the removal operation of the cylinder connection module <NUM> and the boom connection module <NUM> in a case where the distal end boom <NUM> is extended.

Hereinafter, the rotation of the electric motor <NUM> when the boom connection module <NUM> is changed from the inserted state to the removed state is referred to as "forward rotation", and the rotation of the electric motor <NUM> when the cylinder connection module <NUM> is changed from the inserted state to the removed state is referred to as "reverse rotation".

<FIG> are schematic views for describing the operation of the cylinder connection module <NUM>. <FIG> illustrate operation in a case where the cylinder connection module <NUM> changes from the inserted state to the removed state. In <FIG>, the C pin toothless gear <NUM> and the B pin toothless gear <NUM> are illustrated as the integrally formed switch gear G. In addition, in <FIG>, the lock mechanism <NUM> is omitted.

As illustrated in <FIG>, in a contracted state of the distal end boom <NUM> before being extended, the cylinder connection module <NUM> is in the neutral state. That is, the C pin <NUM> is engaged with the C pin receiving part <NUM> of the distal end boom <NUM>, and the distal end boom <NUM> and the cylinder connection module <NUM> are in a connection state.

In a case where the cylinder connection module <NUM> changes from the inserted state to the removed state, the power of the electric motor <NUM> is transmitted to the C pins 150A and 150B through the following first path and second path.

The first path is the C pin toothless gear <NUM> -> the C pin rack bar <NUM> -> the first gear group <NUM> -> the one C pin 150A. The second path is the C pin toothless gear <NUM> -> the C pin rack bar <NUM> -> the second gear group <NUM> -> the other C pin 150B.

As illustrated in <FIG>, when the electric motor <NUM> performs reverse rotation, the C pin toothless gear <NUM> rotates in the R1 direction. With the rotation of the C pin toothless gear <NUM>, the C pin rack bar <NUM> is displaced to the + side in the Y direction (right side in <FIG>). Accordingly, in the first path, the one C pin 150A is displaced to the - side in the Y direction (left side in <FIG>) via the first gear group <NUM>. In the second path, the other C pin 150B is displaced to the + side in the Y direction (right side in <FIG>) via the second gear group <NUM>. That is, when the cylinder connection module <NUM> changes from the inserted state to the removed state, the one C pin 150A and the other C pin 150B are displaced in directions approaching each other.

Finally, as illustrated in <FIG>, the C pins 150A and 150B are completely detached from the C pin receiving part <NUM>, and the cylinder connection module <NUM> and the distal end boom <NUM> are brought into a disconnection state. Note that a state change of the cylinder connection module <NUM> from the removed state to the inserted state is automatically performed on the basis of the biasing force of the C pin biasing mechanism <NUM>.

<FIG> are schematic views for describing the operation of the boom connection module <NUM>. <FIG> illustrate operation in a case where the boom connection module <NUM> changes from the inserted state to the removed state. In <FIG>, the C pin toothless gear <NUM> and the B pin toothless gear <NUM> are illustrated as the integrally formed switch gear G. In addition, in <FIG>, the lock mechanism <NUM> is omitted.

As illustrated in <FIG>, in the contracted state of the distal end boom <NUM> before being extended, the cylinder connection module <NUM> and the boom connection module <NUM> are in the neutral state. That is, the distal end boom <NUM> is connected to the intermediate boom <NUM> via the B pin <NUM> and is not movable in the telescoping direction with respect to the intermediate boom <NUM>.

In a case where the boom connection module <NUM> changes from the inserted state to the removed state, the power of the electric motor <NUM> is transmitted through a path of the B pin toothless gear <NUM> -> the one B pin rack bar 220B -> the synchronous gear <NUM> -> the other B pin rack bar 220A.

As illustrated in <FIG>, when the electric motor <NUM> performs forward rotation, the B pin toothless gear <NUM> rotates in the R2 direction. With the rotation of the B pin toothless gear <NUM>, the one B pin rack bar 220B is displaced to the + side in the Y direction (right side in <FIG>). In addition, the synchronous gear <NUM> rotates, and the other B pin rack bar 220A is displaced to the - side in the Y direction (left side in <FIG>) in response to the rotation of the synchronous gear <NUM>. That is, when the boom connection module <NUM> changes from the inserted state to the removed state, the one B pin rack bar 220B and the other B pin rack bar 220A are displaced in directions approaching each other. As a result, the B pin holding part <NUM> connected to the B pin rack bars 220A and 220B also contracts, and the B pin <NUM> held by the B pin holding part <NUM> is gradually removed from the proximal end side B pin receiving part <NUM>.

Finally, as illustrated in <FIG>, the B pins 315A and 315B are completely detached from the proximal end side B pin receiving part <NUM>, and the distal end boom <NUM> and the intermediate boom <NUM> are brought into the disconnection state. Note that a state change of the boom connection module <NUM> from the removed state to the inserted state is automatically performed on the basis of the biasing force of the B pin biasing mechanism <NUM>.

<FIG> is a timing chart illustrating an example of control during the extending operation of the telescopic boom <NUM>. For convenience, a case where the distal end boom <NUM> is extended from a fully retracted state will be described. Note that the inserted state and the removed state of the B pin <NUM> correspond to the inserted state and the removed state of the boom connection module <NUM>, respectively and the inserted state and the removed state of the C pin <NUM> correspond to the inserted state and the removed state of the cylinder connection module <NUM>, respectively. Switching between on and off of the electric motor <NUM>, the brake <NUM>, and the clutch <NUM> is controlled by the control device <NUM>.

Sections T0 to T1 in <FIG> are initial contracted states of the extending operation, and the cylinder connection module <NUM> and the boom connection module <NUM> are in the neutral state (see <FIG> and <FIG>). That is, the distal end boom <NUM> is connected to the intermediate boom <NUM> via the B pin <NUM> and is not movable in the telescoping direction with respect to the intermediate boom <NUM>. In addition, the C pin <NUM> is engaged with the C pin receiving part <NUM> of the distal end boom <NUM>, and the distal end boom <NUM> and the cylinder part <NUM> are in a connection state.

States of respective mechanical elements in the sections T0 to T1 are as follows.

When receiving the extension operation of the telescopic boom <NUM> by the operator (timing T1), the control device <NUM> controls the clutch <NUM> to bring the clutch <NUM> into an on state (connected state) and causes the electric motor <NUM> to perform forward rotation. The B pin <NUM> gradually changes from the inserted state to the removed state.

States of respective mechanical elements in the sections T1 to T2 are as follows.

At this time, when the B pin <NUM> is difficult to remove, for example, due to being caught by the proximal end side B pin receiving part <NUM> of the intermediate boom <NUM>, rotating elements in the power transmission path from the electric motor <NUM> to the boom connection module <NUM> cannot rotate smoothly, and an overload occurs. Then, there is a risk that a large current flows through the electric motor <NUM>, resulting in heat generation and burnout.

In the present embodiment, the torque limiter <NUM> is disposed in the power transmission path, and a load applied to the mechanical element in the power transmission path is maintained at a predetermined value or less. Therefore, it is possible to prevent the mechanical element from being damaged due to difficulty in removal of the B pin <NUM> during the removal operation of the B pin <NUM>.

The control device <NUM> determines a state of the B pin <NUM> on the basis of the detection result of the position detection device <NUM> and the like, and when the B pin <NUM> changes to the removed state (timing T2), the control device <NUM> stops the electric motor <NUM> while maintaining the clutch <NUM> in an on state. In addition, the brake <NUM> is turned on to maintain the removed state of the B pin <NUM>.

Note that timing to turn off the electric motor <NUM> and timing to turn on the brake <NUM> are appropriately controlled by the control device <NUM>. For example, by turning on the brake <NUM> and then turning off the electric motor <NUM>, it is possible to reliably maintain the removed state of the B pin <NUM>.

At timing T2, the B pin <NUM> is completely detached from the proximal end side B pin receiving part <NUM>, and the distal end boom <NUM> and the intermediate boom <NUM> are brought into the disconnection state. Although not illustrated, in sections T2 to T3, the control device <NUM> controls the telescoping actuator <NUM> to move the cylinder part <NUM> in the extending direction. Accordingly, the distal end boom <NUM> connected to the cylinder part <NUM> via the cylinder connection module <NUM> moves in the extending direction.

States of respective mechanical elements in the sections T2 to T3 are as follows.

When the distal end boom <NUM> moves to a predetermined position and is brought into the extended state (timing T3), the control device <NUM> controls the clutch <NUM> and the brake <NUM> to bring the clutch <NUM> and the brake <NUM> into an off state. The boom connection module <NUM> is restored to the neutral state by the biasing force of the B pin biasing mechanism <NUM>. Accordingly, the B pin <NUM> changes from the removed state to the inserted state and is inserted into the distal end side B pin receiving part <NUM>.

States of respective mechanical elements in sections T3 to T4 are as follows.

As described above, in the insertion operation of the B pin <NUM>, the boom connection module <NUM> is restored to the neutral state using the B pin biasing mechanism <NUM> In this case, when the power transmission path from the electric motor <NUM> to the boom connection module <NUM> is connected, the electric motor <NUM> rotates in a direction opposite to the rotation direction during the removal operation in accordance with the insertion operation of the B pin <NUM>. Then, the rotating elements including the electric motor <NUM> may not stop at the neutral position due to inertial force, and thrust for rotating the switch gear G in a direction in which the C pin <NUM> is removed due to overrun may be generated.

In this regard, in the present embodiment, the clutch <NUM> is disposed in the power transmission path, and the transmission of power from the boom connection module <NUM> to the electric motor <NUM> is cut off when the boom connection module <NUM> is restored to the neutral state using the B pin biasing mechanism <NUM>. Therefore, during the insertion operation of the B pin <NUM>, it is possible to prevent the C pin <NUM> from changing to the removed state temporarily and becoming unstable in operation.

When the B pin <NUM> is completely engaged with the distal end side B pin receiving part <NUM> (timing T4), the control device <NUM> changes the C pin <NUM> to the removed state in order to return the telescoping actuator <NUM> to a contracted state. That is, at timing T5, the control device <NUM> controls the clutch <NUM> to bring the clutch <NUM> into the on state (connected state) and causes the electric motor <NUM> to perform reverse rotation. The C pin <NUM> gradually changes from the inserted state to the removed state.

States of respective mechanical elements in the sections T5 to T6 are as follows.

At this time, when the C pin <NUM> is difficult to remove, for example, due to being caught by the C pin receiving part <NUM> of the distal end boom <NUM>, the rotating elements in the power transmission path from the electric motor <NUM> to the cylinder connection module <NUM> cannot smoothly rotate, and an overload occurs. Then, there is a risk that a large current flows through the electric motor <NUM>, resulting in heat generation and burnout.

In the present embodiment, the torque limiter <NUM> is disposed in the power transmission path, and a load applied to the mechanical element in the power transmission path is maintained at a predetermined value or less. Therefore, it is possible to prevent the mechanical element from being damaged due to difficulty in removal of the C pin <NUM> during the removal operation of the C pin <NUM>.

The control device <NUM> determines a state of the C pin <NUM> on the basis of the detection result of the position detection device <NUM> and the like, and when the C pin <NUM> changes to the removed state (timing T6), the control device <NUM> stops the electric motor <NUM> while maintaining the clutch <NUM> in the on state. In addition, the brake <NUM> is brought into an on state, and the C pin <NUM> is maintained in the removed state.

At timing T6, the C pin <NUM> is completely detached from the C pin receiving part <NUM> of the distal end boom <NUM>, and the cylinder connection module <NUM> and the distal end boom <NUM> are brought into a disconnection state. Although not illustrated, in sections T6 to T7, the control device <NUM> controls the telescoping actuator <NUM> to move the cylinder part <NUM> in a contraction direction. At this time, since the cylinder part <NUM> is in a disconnection state with respect to the distal end boom <NUM>, the intermediate boom <NUM>, and the proximal end boom <NUM>, the cylinder part <NUM> moves alone in the contraction direction.

States of respective mechanical elements in the sections T6 to T7 are as follows.

When the telescoping actuator <NUM> is brought into the contracted state (timing T7), the control device <NUM> controls the clutch <NUM> and the brake <NUM> to bring the clutch <NUM> and the brake <NUM> into the off state. The cylinder connection module <NUM> is restored to the neutral state by the biasing force of the C pin biasing mechanism <NUM>. Accordingly, the C pin <NUM> changes from the removed state to the inserted state and engages with the C pin receiving part <NUM> of the intermediate boom <NUM>. In addition, the B pin holding part <NUM> of the intermediate boom <NUM> is engaged with the B pin rack bars 220A and 220B.

States of respective mechanical elements in sections T7 to T8 are as follows.

As described above, in the insertion operation of the C pin <NUM>, the cylinder connection module <NUM> is restored to the neutral state using the C pin biasing mechanism <NUM>. In this case, when the power transmission path from the electric motor <NUM> to the cylinder connection module <NUM> is connected, the electric motor <NUM> rotates in a direction opposite to the rotation direction during the removal operation in accordance with the insertion operation of the C pin <NUM>. Then, the rotating elements including the electric motor <NUM> may not stop at the neutral position due to inertial force, and thrust for rotating the switch gear G in a direction in which the B pin <NUM> is removed due to overrun may be generated.

In this regard, in the present embodiment, the clutch <NUM> is disposed in the power transmission path, and the transmission of power from the cylinder connection module <NUM> to the electric motor <NUM> is cut off when the cylinder connection module <NUM> is restored to the neutral state using the C pin biasing mechanism <NUM>. Therefore, it is possible to prevent the B pin <NUM> from changing to the removed state temporarily during the insertion operation of the C pin <NUM> and becoming unstable in operation.

When the C pin <NUM> is completely engaged with the C pin receiving part <NUM> of the intermediate boom <NUM> (timing T8), the neutral state is maintained. Note that in a case where the intermediate boom <NUM> is extended, operation similar to the operation described above is performed. In addition, in a case where the distal end boom <NUM> or the intermediate boom <NUM> is contracted, operation in a direction opposite to a direction described above is performed.

Here, lubricant oil is generally applied to the mechanical elements constituting the pin insertion/removal actuator <NUM> so that the removal operation and the insertion operation of the B pin <NUM> and the C pin <NUM> are smoothly performed. In this case, if the viscosity of the lubricant oil increases due to ambient environmental temperature or aging, the insertion and removal operation of the B pin <NUM> and the C pin <NUM> may be hindered. In particular, since the insertion operation of the B pin <NUM> and the C pin <NUM> is performed using the biasing force, the lubricant oil of high viscosity may become resistance and operation time may become unstable.

Therefore, in the present embodiment, when the C pin <NUM> is restored to the inserted state by the biasing force of the C pin biasing mechanism <NUM> and when the B pin <NUM> is restored to the inserted state by the biasing force of the B pin biasing mechanism <NUM>, the control device <NUM> executes motor assist processing of operating the electric motor <NUM>.

<FIG> is a timing chart for describing the extending operation of the telescopic boom <NUM> to which the motor assist processing is applied.

As illustrated in <FIG>, in a case where the insertion operation of the B pin <NUM> is performed in the sections T3 to T4, the control device <NUM> causes the electric motor <NUM> to perform reverse rotation for a short period of time (for example, <NUM> to <NUM> sec. In addition, in a case where the insertion operation of the C pin <NUM> is performed in the sections T7 to T8, the control device <NUM> causes the electric motor <NUM> to perform forward rotation. As a result, it is possible to release a state in which the C pin <NUM> or the B pin <NUM> is difficult to move due to the viscosity of the lubricant oil by the power of the electric motor <NUM>, and thereafter it is possible to smoothly restore to the neutral state by the subsequent biasing force of the C pin biasing mechanism <NUM> or the B pin biasing mechanism <NUM>.

This motor assist processing may be always performed during the insertion operation of the B pin <NUM> and the C pin <NUM> or may be performed only in a case where a predetermined condition is satisfied. The predetermined condition includes ambient environmental temperature (for example, -<NUM> or less), use time, and the like. In addition, the operator may manually set whether to perform the motor assist processing. In addition, the motor assist processing may be selectively performed on the B pin <NUM> and the C pin <NUM>.

Furthermore, the control device <NUM> may determine the drive start timing and drive time of the electric motor <NUM> in the motor assist processing according to the environmental temperature. As a result, since appropriate motor assist processing is performed, it is possible to prevent thrust from being generated in a direction in which the C pin <NUM> or the B pins <NUM> and <NUM> are removed due to overrun.

As described above, the mobile crane <NUM> (work machine) according to the present embodiment includes: the telescopic boom <NUM> having the first boom (for example, the distal end boom <NUM>) and the second boom (for example, the intermediate boom <NUM>) that overlap each other in a telescopic manner; the telescoping actuator <NUM> that moves the first boom in the telescoping direction with respect to the second boom; the electric motor <NUM> (electrical drive source) provided in the cylinder part <NUM> (movable portion) of the telescoping actuator <NUM>; the C pin <NUM> (first fixing pin) that connects the telescoping actuator <NUM> and the first boom; the C pin biasing mechanism <NUM> (first biasing mechanism) that biases the C pin <NUM> to maintain a connection state between the telescoping actuator <NUM> and the first boom; the cylinder connection module <NUM> (first connection mechanism) that operates on the basis of power of the electric motor <NUM> and switches between the connection state and a disconnection state between the telescoping actuator <NUM> and the first boom by inserting and removing the C pin <NUM>; the B pins <NUM> and <NUM> (second fixing pins) that connect the first boom and the second boom; the B pin biasing mechanism <NUM> (second biasing mechanism) that biases the B pins <NUM> and <NUM> to maintain a connection state between the first boom and the second boom; the boom connection module <NUM> (second connection mechanism) that operates on the basis of the power of the electric motor <NUM> and switches between the connection state and a disconnection state between the first boom and the second boom by inserting and removing the B pins <NUM> and <NUM>; and the clutch <NUM> that is disposed in the power transmission path from the electric motor <NUM> to the cylinder connection module <NUM> and the boom connection module <NUM> and discretionally intermittently transmits the power of the electric motor <NUM> to the cylinder connection module <NUM> and the boom connection module <NUM>.

Specifically, the clutch <NUM> cuts off the power of the electric motor <NUM> (electrical drive source) at least when the C pin <NUM> (first fixing pin) is restored by the biasing force of the C pin biasing mechanism <NUM> (first biasing mechanism) and/or when the B pins <NUM> and <NUM> (second fixing pins) are restored by the biasing force of the B pin biasing mechanism <NUM> (second biasing mechanism).

According to the mobile crane <NUM>, since the cylinder connection module <NUM> and the boom connection module <NUM> are electric, it is not necessary to provide a hydraulic circuit as in conventional structures in the internal space of the telescopic boom <NUM>. Therefore, it is possible to improve the degree of freedom in terms of design in the internal space of the telescopic boom <NUM> by effectively utilizing a space used by the hydraulic circuit.

In addition, the clutch <NUM> is disposed in the power transmission path, and the transmission of the power from the cylinder connection module <NUM> or the boom connection module <NUM> to the electric motor <NUM> is cut off when the neutral state is restored using the C pin biasing mechanism <NUM> or the B pin biasing mechanism <NUM>. Thus, it is possible to prevent the C pin <NUM> or the B pins <NUM> and <NUM> from changing to the removed state temporarily during the insertion operation of the B pins <NUM> and <NUM> or the C pin <NUM> and becoming unstable in operation.

Therefore, according to the mobile crane <NUM>, it is possible to improve the degree of freedom in terms of design around a telescopic boom <NUM> and an increase in the reliability when the boom <NUM> is telescoping.

In addition, the mobile crane <NUM> includes the speed reducer <NUM> that decelerates a driving speed of the electric motor <NUM> (electrical drive source) and outputs the decelerated driving speed, and the clutch <NUM> is disposed between the electric motor <NUM> and the speed reducer <NUM>. As a result, it is possible to reduce the transmission torque capacity of the clutch <NUM> and downsize the clutch <NUM>.

In addition, in the mobile crane <NUM>, the clutch <NUM> includes an electromagnetic clutch, a mechanical clutch, or a torque diode. As a result, it is possible to appropriately select a general-purpose clutch as necessary and easily switch between transmission and cutoff of the power from the electric motor <NUM>.

Although the invention made by the present inventors has been specifically described above on the basis of the embodiment, the present invention is not limited to the embodiment described above, and can be modified without departing from the gist thereof.

For example, as the electric motor <NUM>, a hollow motor having a hollow stator disposed on the inner side and a rotor disposed on the outer side may be applied, the hollow motor may be disposed on the outer periphery of the piston rod part <NUM>, and a transmission gear (not illustrated) of the transmission mechanism <NUM> may mesh with a gear provided on the rotor.

In addition, the disposition of the electric motor <NUM> described in the embodiment is an example, and the electric motor <NUM> may be disposed so that the output shaft (not illustrated) extends in the Y direction or the Z direction.

In addition, the electric motor <NUM> is not limited to the rotary motor, and a linear motor (linear motion actuator) that outputs linear motion can also be used.

In addition, the work machine according to the present invention is not limited to the mobile crane and can also be applied to other work machines (for example, a vehicle for work at height) including a telescopic boom.

Claim 1:
A work machine (<NUM>) comprising:
a telescopic boom (<NUM>) having a first boom (<NUM>) and a second boom (<NUM>) that are telescopically overlapped;
a telescoping actuator (<NUM>) that moves the first boom (<NUM>) in a telescoping direction with respect to the second boom (<NUM>);
an electrical drive source (<NUM>) provided in a movable portion (<NUM>) of the telescoping actuator (<NUM>);
a first fixing pin (<NUM>) that connects the telescoping actuator (<NUM>) and the first boom (<NUM>);
a first biasing mechanism (<NUM>) that biases the first fixing pin (<NUM>) to maintain a connection state between the telescoping actuator (<NUM>) and the first boom (<NUM>) ;
a first connection mechanism (<NUM>) that operates on the basis of the power of the electrical drive source (<NUM>), the first connection mechanism (<NUM>) switching between the connection state and a disconnection state between the telescoping actuator (<NUM>) and the first boom (<NUM>) by inserting and removing the first fixing pin (<NUM>);
the work machine being characterized in that it further comprises:
a second fixing pin (<NUM>, <NUM>) that connects the first boom (<NUM>) and the second boom (<NUM>);
a second biasing mechanism (<NUM>) that biases the second fixing pin (<NUM>, <NUM>) to maintain a connection state between the first boom (<NUM>) and the second boom (<NUM>);
a second connection mechanism (<NUM>) that operates on the basis of the power of the electrical drive source (<NUM>), the second connection mechanism (<NUM>) switching between the connection state and a disconnection state between the first boom (<NUM>) and the second boom (<NUM>) by inserting and removing the second fixing pin (<NUM>, <NUM>); and
a clutch (<NUM>) that is disposed in a power transmission path from the electrical drive source (<NUM>) to the first connection mechanism (<NUM>) and the second connection mechanism (<NUM>), the clutch (<NUM>) discretionally intermittently transmitting the power of the electrical drive source (<NUM>) to the first connection mechanism (<NUM>) and the second connection mechanism (<NUM>).