Patent Description:
Patent Literature <NUM> discloses a mobile crane that includes a telescopic boom in which a plurality of boom elements overlap in a nested shape (also referred to as a telescopic shape. ), and a hydraulic telescopic cylinder extending the telescopic boom.

The telescopic boom includes a boom connecting pin that connects adjacent overlapping boom elements. A boom element (hereinafter, referred to as a movable boom element. ) released from the connection by the boom connecting pin is movable in a longitudinal direction (also referred to as a telescopic direction. ) with respect to other boom elements.

A telescopic cylinder includes a rod member and a cylinder member. Such a telescopic cylinder connects the cylinder member to the movable boom element via the cylinder connecting pin. When the cylinder member moves in a telescopic direction in this state, the movable boom element moves together with the cylinder member, and the telescopic boom extends and retracts. French Patent Application Publication <CIT> relates to a work machine according to the preamble of claim <NUM>. The work machine includes an actuator, an electric driven source, an operating unit, and joint. The actuator extends and retracts a telescopic boom. The electric drive source is provided in the actuator and drives using power supplied from a power source. The operating unit operates based on power of the electric drive source. The joint has a drive-side element and a driven-side element. The drive-side element is fixed to a first transmission shaft that rotates on the basis of the power of the electric drive source. The driven-side element is fixed to a second transmission shaft connected to the operating unit. Furthermore, the joint is able to take a transmission state in which both the drive-side element and the driven-side element rotate and a non-transmission state in which only either the drive-side element or the driven-side element rotates. Japanese Patent Application Publication <CIT> relates to a work machine including an actuator, an electric driven source, an operating unit, and joint. The actuator extends and retracts a telescopic boom. The electric drive source is provided in the actuator and drives using power supplied from a power source. The operating unit operates based on power of the electric drive source. The joint has a drive-side element and a driven-side element. The drive-side element is fixed to a first transmission shaft that rotates on the basis of the power of the electric drive source. The driven-side element is fixed to a second transmission shaft connected to the operating unit. Furthermore, the joint is able to take a transmission state in which both the drive-side element and the driven-side element rotate and a non-transmission state in which only either the drive-side element or the driven-side element rotates.

However, the crane as described above includes a hydraulic actuator that moves a boom connecting pin, a hydraulic actuator that moves a cylinder connecting pin, and a hydraulic circuit that supplies pressure oil to each actuator. Such a hydraulic circuit is provided, for example, around the telescopic boom. For this reason, a degree of freedom in design around the telescopic boom is likely to be reduced.

An object of the present invention is to provide a work machine capable of improving a degree of freedom in design around a telescopic boom.

According to a first aspect, the present invention provides a work machine according to independent claim <NUM>. Further aspects of the invention are set forth in the dependent claims, the drawings and the following description. According to the present invention, a work machine includes:.

According to the present invention, it is possible to improve a degree of freedom in design around a telescopic boom.

Hereinafter, an example of embodiments according to the present invention will be described in detail with reference to the drawings. Note that a crane according to an embodiment to be described later is an example of a work machine according to the present invention, and the present invention is not limited to the embodiment to be described later.

<FIG> is a schematic diagram of a mobile crane <NUM> (in the case illustrated, a rough terrain crane) according to the present embodiment. The mobile crane <NUM> corresponds to an example of a work machine.

Examples of the mobile crane include an all-terrain crane, a truck crane, and a load-type truck crane (also referred to as a cargo crane. However, the work machine according to the present invention is not limited to the mobile crane, and can also be applied to other work vehicles (for example, a crane or a high-place work vehicle) including a telescopic boom.

Hereinafter, first, an outline of the mobile crane <NUM> and a telescopic boom <NUM> included in the mobile crane <NUM> will be described. Thereafter, a specific structure and operation of an actuator <NUM>, which is a feature of the mobile crane <NUM> according to the present embodiment, will be described.

As illustrated in <FIG>, the mobile crane <NUM> includes a traveling body <NUM>, an outrigger <NUM>, a turning table <NUM>, the telescopic boom <NUM>, the actuator <NUM> (not illustrated in <FIG>), a derricking cylinder <NUM>, a wire <NUM>, and a hook <NUM>.

The traveling body <NUM> has a plurality of wheels <NUM>. The outriggers <NUM> are provided at four corners of the traveling body <NUM>. The turning table <NUM> is turnably provided on an upper portion of the traveling body <NUM>. A proximal end portion of the telescopic boom <NUM> is fixed to the turning table <NUM>. The actuator <NUM> extends and retracts the telescopic boom <NUM>. The derricking cylinder <NUM> derricks the telescopic boom <NUM>. The wire <NUM> hangs down from a tip portion of the telescopic boom <NUM>. The hook <NUM> is provided at a tip of the wire <NUM>.

Next, the telescopic boom <NUM> will be described with reference to <FIG> and <FIG> are schematic diagrams for describing a structure and an extending and retracting operation of the telescopic boom <NUM>.

<FIG> illustrates the telescopic boom <NUM> in an extended state. <FIG> illustrates the telescopic boom <NUM> in a retracted state. <FIG> illustrates the telescopic boom <NUM> in which only the tip boom element <NUM> to be described later is extended.

The telescopic boom <NUM> includes a plurality of boom elements. Each of the plurality of boom elements has a tubular shape. The plurality of boom elements are combined with each other in a telescopic shape. Specifically, in the retracted state, the plurality of boom elements are a tip boom element <NUM>, an intermediate boom element <NUM>, and a proximal-end boom element <NUM> in order from the inside.

Note that in the case of the present embodiment, the tip boom element <NUM> and the intermediate boom element <NUM> correspond to an example of a first boom element movable in the telescopic direction. When tip boom element <NUM> moves in a telescopic direction with respect to the intermediate boom element <NUM>, the tip boom element <NUM> corresponds to an example of the first boom element, and the intermediate boom element <NUM> corresponds to an example of a second boom element. When the intermediate boom element <NUM> moves in the telescopic direction with respect to the proximal-end boom element <NUM>, the intermediate boom element <NUM> corresponds to an example of the first boom element, and the proximal-end boom element <NUM> corresponds to an example of the second boom element. Movement of the proximal-end boom element <NUM> in the telescopic direction is restricted.

The state of the telescopic boom transitions from the retracted state illustrated in <FIG> to the extended state illustrated in <FIG> by sequentially extending the telescopic boom <NUM> from the boom element (that is, the tip boom element <NUM>) disposed on the inner side.

In the extended state, the intermediate boom element <NUM> is disposed between the proximal-end boom element <NUM> on the most proximal-end side and the tip boom element <NUM> on the most tip side. Note that a plurality of intermediate boom elements may be provided.

The structure of the telescopic boom <NUM> is substantially the same as the structure of the telescopic boom known in the related art, but for convenience of description of the structure and operation of the actuator <NUM> to be described later, the structures of the tip boom element <NUM> and the intermediate boom element <NUM> will be described below.

The tip boom element <NUM> has a tubular shape as illustrated in <FIG>. The tip boom element <NUM> has an internal space capable of accommodating the actuator <NUM>. The tip boom element <NUM> has a pair of cylinder pin receiving parts 141a and a pair of boom pin receiving parts 141b at a proximal end portion.

The pair of cylinder pin receiving parts 141a is provided coaxially with each other at the proximal end portion of the tip boom element <NUM>. Each of the pair of cylinder pin receiving parts 141a can be engaged with and disengaged from a pair of cylinder connecting pins 454a and 454b (also referred to as a first connecting member. ) provided in a cylinder member <NUM> of a telescopic cylinder <NUM>. That is, the pair of cylinder pin receiving parts 141a can take either an engaged state of being engaged with the pair of cylinder connecting pins 454a and 454b or a disengaged state of being disengaged from the pair of cylinder connecting pins 454a and 454b.

The cylinder connecting pins 454a and 454b move in an axial direction thereof based on an operation of a cylinder connecting mechanism <NUM> included in the actuator <NUM> to be described later. In a state where the pair of cylinder connecting pins 454a and 454b and the pair of cylinder pin receiving parts 141a are engaged with each other, the tip boom element <NUM> is movable in the telescopic direction together with the cylinder member <NUM>.

The pair of boom pin receiving parts 141b is provided coaxially with each other on the proximal-end side of the cylinder pin receiving part 141a. Each of the boom pin receiving parts 141b can be engaged with and disengaged from the pair of boom connecting pins 144a (also referred to as a second connecting member. That is, the pair of boom pin receiving parts 141b can take either an engaged state of being engaged with the pair of boom connecting pins 144a or a disengaged state of being disengaged from the pair of boom connecting pins 144a.

Each of the pair of boom connecting pins 144a connects the tip boom element <NUM> and the intermediate boom element <NUM>. The pair of boom connecting pins 144a moves in the axial direction thereof based on an operation of a boom connecting mechanism <NUM> included in the actuator <NUM>. The pair of boom connecting pins 144a may be regarded as constituent members of the boom connecting mechanism <NUM> (see <FIG>).

In a state in which the tip boom element <NUM> and the intermediate boom element <NUM> are connected by the pair of boom connecting pins 144a, the boom connecting pin 144a is inserted so as to be bridged between the boom pin receiving part 141b of the tip boom element <NUM> and a first boom pin receiving part 142b or a second boom pin receiving part 142c of the intermediate boom element <NUM> to be described later.

In a state where the tip boom element <NUM> and the intermediate boom element <NUM> are connected (also referred to as a connected state. ), the tip boom element <NUM> is prohibited from moving in the telescopic direction with respect to the intermediate boom element <NUM>.

Meanwhile, when the tip boom element <NUM> and the intermediate boom element <NUM> are disconnected (also referred to as a disconnected state. ), the tip boom element <NUM> can move in the telescopic direction with respect to the intermediate boom element <NUM>.

The intermediate boom element <NUM> has a cylindrical shape as illustrated in <FIG>. The intermediate boom element <NUM> has an internal space capable of accommodating the tip boom element <NUM>. The intermediate boom element <NUM> has a pair of cylinder pin receiving parts 142a, a pair of first boom pin receiving parts 142b, a pair of second boom pin receiving parts 142c, and a pair of third boom pin receiving parts 142d at the proximal end portion.

The pair of cylinder pin receiving parts 142a and the pair of first boom pin receiving parts 142b are substantially similar to the pair of cylinder pin receiving parts 141a and the pair of boom pin receiving parts 141b of the tip boom element <NUM>, respectively.

The pair of third boom pin receiving parts 142d is provided coaxially with each other on the proximal-end side of the pair of first boom pin receiving parts 142b. A pair of boom connecting pins 144b is inserted into the pair of third boom pin receiving parts 142d, respectively. The pair of boom connecting pins 144b connects the intermediate boom element <NUM> and the proximal-end boom element <NUM>.

The pair of second boom pin receiving parts 142c is provided coaxially with each other at the tip portion of the intermediate boom element <NUM>. The pair of boom connecting pins 144a is inserted into the pair of second boom pin receiving parts 142c, respectively.

Hereinafter, the actuator <NUM> will be described with reference to <FIG>. The actuator <NUM> is an actuator that extends and retracts the above-described telescopic boom <NUM> (see <FIG> and <FIG>).

The actuator <NUM> includes the telescopic cylinder <NUM> and a pin moving module <NUM>. The actuator <NUM> is disposed in the internal space of the tip boom element <NUM> in the retracted state of the telescopic boom <NUM> (the state illustrated in <FIG>).

The telescopic cylinder <NUM> includes a rod member <NUM> (also referred to as a fixing-side member. See <FIG>) and the cylinder member <NUM> (also referred to as a movable side member. The telescopic cylinder <NUM> moves a boom element (for example, the tip boom element <NUM> or the intermediate boom element <NUM>) connected to the cylinder member <NUM> via the cylinder connecting pins 454a and 454b to be described later in the telescopic direction. Since the structure of the telescopic cylinder <NUM> is substantially similar to the structure of the conventionally known telescopic cylinder, a detailed description thereof will be omitted.

The pin moving module <NUM> includes a housing <NUM>, an electric motor <NUM>, a brake mechanism <NUM>, a transmission mechanism <NUM>, a position information detection device <NUM>, a cylinder connecting mechanism <NUM>, a boom connecting mechanism <NUM>, and a lock mechanism <NUM> (see <FIG>).

Hereinafter, each member constituting the actuator <NUM> will be described with reference to a state of being incorporated in the actuator <NUM>. In addition, in the description of the actuator <NUM>, an orthogonal coordinate system (X, Y, Z) illustrated in each drawing is used. However, the arrangement of each unit constituting the actuator <NUM> is not limited to the arrangement of the present embodiment.

In the orthogonal coordinate system illustrated in each drawing, an X direction coincides with the telescopic direction of the telescopic boom <NUM> mounted on the mobile crane <NUM>. A + side in the X direction is also referred to as an extending direction in the telescopic direction. A - side in the X direction is also referred to as a retracting direction in the telescopic direction. For example, a Z direction coincides with a vertical direction of the mobile crane <NUM> in a state where a derricking angle of the telescopic boom <NUM> is <NUM> (also referred to as a fallen state of the telescopic boom <NUM>. For example, a Y direction coincides with a vehicle width direction of the mobile crane <NUM> in a state where the telescopic boom <NUM> faces forward. However, the Y direction and the Z direction are not limited to the above directions as long as they are two directions orthogonal to each other.

The housing <NUM> is fixed to the cylinder member <NUM> of the telescopic cylinder <NUM>. The housing <NUM> accommodates the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> in the internal space. The housing <NUM> supports the electric motor <NUM> via the transmission mechanism <NUM>. Furthermore, the housing <NUM> also supports a brake mechanism <NUM> to be described later. Such a housing <NUM> unitizes each of the above-described elements. Such a configuration contributes to miniaturization of the pin moving module <NUM>, improvement in productivity, and improvement in system reliability.

Specifically, the housing <NUM> has a box-shaped first housing element <NUM> and a box-shaped second housing element <NUM>.

The first housing element <NUM> accommodates the cylinder connecting mechanism <NUM> to be described later in the internal space. The rod member <NUM> is inserted through the first housing element <NUM> in the X direction. An end portion of the cylinder member <NUM> is fixed to a side wall of the first housing element <NUM> on the + side in the X direction (the left side in <FIG> and the right side in <FIG>).

The first housing element <NUM> has through holes 400a and 400b (see <FIG> and <FIG>) in side walls on both sides in the Y direction. A pair of cylinder connecting pins 454a and 454b of the cylinder connecting mechanism <NUM> is inserted into the through holes 400a and 400b, respectively.

The second housing element <NUM> is provided on a + side in the Z direction of the first housing element <NUM>. The second housing element <NUM> accommodates the boom connecting mechanism <NUM> to be described later in the internal space. A second transmission shaft <NUM> (see <FIG>) of the transmission mechanism <NUM> to be described later is inserted into the second housing element <NUM> in the X direction.

The second housing element <NUM> has through holes 401a and 401b (see <FIG> and <FIG>) in side walls on both sides in the Y direction. A pair of second rack bars 461a and 461b of the boom connecting mechanism <NUM> are inserted into the through holes 401a and 401b, respectively.

The electric motor <NUM> corresponds to an example of an electric drive source, and is supported by the housing <NUM> via a speed reducer <NUM> of the transmission mechanism <NUM>. Specifically, the electric motor <NUM> is disposed around the cylinder member <NUM> (for example, + side in the Z direction) and around the second housing element <NUM> (for example, the - side in the X direction) in a state where an output shaft (not illustrated) is parallel to the X direction (also referred to as a longitudinal direction of the cylinder member <NUM>. Such an arrangement contributes to miniaturization of the pin moving module <NUM> in the Y direction and the Z direction.

The electric motor <NUM> as described above is connected to, for example, a power supply device provided on the turning table <NUM> via a power supply cable. Furthermore, the electric motor <NUM> is connected to, for example, a control unit 44b (see <FIG>) provided on a turning table <NUM> via a control signal transmission cable.

Each of the above-described cables can be unreeled and wound by a cord reel that is provided outside the proximal end portion of the telescopic boom <NUM> or on the turning table <NUM> (see <FIG>).

In addition, the electric motor <NUM> includes manual operation unit <NUM> (see <FIG>) that can be operated by a manual handle (not illustrated). The manual operation unit <NUM> is for manually performing the state transition of the pin moving module <NUM>. When the manual operation unit <NUM> is turned by the manual handle at the time of failure or the like, an output shaft of the electric motor <NUM> rotates and the state of the pin moving module <NUM> transitions.

Note that the number of electric motors may be one or plural (for example, two). When the number of electric motors is one, as in the present embodiment, the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> operate by one electric motor <NUM>. In addition, when the number of electric motors is plural (for example, two), the first electric motor (not illustrated) may operate the cylinder connecting mechanism <NUM>, and the second electric motor (not illustrated) may operate the boom connecting mechanism <NUM>.

Note that in the present embodiment, the electric drive source is the electric motor <NUM> described above. However, the electric drive source is not limited to the electric motor. For example, the electric drive source may be various drive sources that generate driving force based on energization from a power source.

The brake mechanism <NUM> applies a braking force to the electric motor <NUM>. The brake mechanism <NUM> prevents the rotation of the output shaft of the electric motor <NUM> while the electric motor <NUM> stops. As a result, the state of the pin moving module <NUM> is maintained in the stopped state of the electric motor <NUM>.

In addition, the brake mechanism <NUM> may allow the rotation (that is, sliding) of the electric motor <NUM> when an external force of a predetermined magnitude acts on the cylinder connecting mechanism <NUM> or the boom connecting mechanism <NUM> at the time of braking. Such a configuration contributes to prevention of damage to the electric motor <NUM>, each gear, or the like that constitute the actuator <NUM>. Note that when such a configuration is adopted, for example, a friction brake can be adopted as the brake mechanism <NUM>.

Specifically, the brake mechanism <NUM> operates in the retracted state of the cylinder connecting mechanism <NUM> or the retracted state of the boom connecting mechanism <NUM> to be described later to maintain the states of the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM>.

The brake mechanism <NUM> is disposed in front of the transmission mechanism <NUM> to be described later. Specifically, the brake mechanism <NUM> is disposed coaxially with the output shaft of the electric motor <NUM> on the - side in the X direction (that is, the side opposite to the transmission mechanism <NUM> with the electric motor <NUM> as the center) with respect to the electric motor <NUM> (see <FIG>).

Such an arrangement contributes to miniaturization of the pin moving module <NUM> in the Y direction and the Z direction. Note that a front stage means an upstream side (side close to the electric motor <NUM>) in a transmission path through which the power of the electric motor <NUM> is transmitted to the cylinder connecting mechanism <NUM> or the boom connecting mechanism <NUM>. On the other hand, a rear stage means a downstream side (side far from the electric motor <NUM>) in a transmission path through which the power of the electric motor <NUM> is transmitted to the cylinder connecting mechanism <NUM> or the boom connecting mechanism <NUM>.

A brake torque necessary for maintaining the stopped state of the electric motor <NUM> is smaller in the configuration in which the brake mechanism <NUM> is disposed at the front stage of the transmission mechanism <NUM> than in the configuration in which the brake mechanism <NUM> is disposed at the rear stage of the transmission mechanism <NUM> (a speed reducer <NUM> to be described later). For this reason, the configuration in which the brake mechanism <NUM> is disposed at the front stage of the transmission mechanism <NUM> contributes to downsizing of the brake mechanism <NUM>.

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

The transmission mechanism <NUM> transmits power (that is, rotational motion) of the electric motor <NUM> to the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM>. As illustrated in <FIG>, the transmission mechanism <NUM> includes a speed reducer <NUM>, a first transmission shaft <NUM>, a coupling <NUM>, and a second transmission shaft <NUM>.

The speed reducer <NUM> decelerates the rotation of the electric motor <NUM> and transmits the decelerated rotation to the first transmission shaft <NUM>. The speed reducer <NUM> is, for example, a planetary gear mechanism housed in a speed reducer case 431a. The speed reducer <NUM> is provided coaxially with the output shaft of the electric motor <NUM>. Such an arrangement contributes to miniaturization of the pin moving module <NUM> in the Y direction and the Z direction.

The first transmission shaft <NUM> is a shaft-like member, and has an engaging part 432a (see <FIG>) at one end portion (end portion on the + side in the X direction) of an outer peripheral surface thereof. The engaging part 432a is, for example, a ridge extending in the axial direction of the first transmission shaft <NUM>.

One end portion of the first transmission shaft <NUM> is connected to a drive-side element <NUM> of the coupling <NUM> to be described later. In addition, the other end portion (end portion on the - side in the X direction) of the first transmission shaft <NUM> is connected to an output shaft (not illustrated) of the speed reducer <NUM>. The first transmission shaft <NUM> rotates together with the output shaft of the speed reducer <NUM>. It may be understood that the first transmission shaft <NUM> rotates on the basis of the power of the electric motor <NUM>. The first transmission shaft <NUM> transmits the rotation of the output shaft of the speed reducer <NUM> to the drive-side element <NUM>. Note that the first transmission shaft <NUM> may be integrated with the output shaft of the speed reducer <NUM>.

The coupling <NUM> will be described with reference to <FIG>, <FIG>. The coupling <NUM> has the drive-side element <NUM> and a driven-side element <NUM>.

The drive-side element <NUM> includes a drive-side base part <NUM> and a drive-side transmission part <NUM>.

The drive-side base part <NUM> may have, for example, a disk shape. The drive-side base part <NUM> has a through hole <NUM> penetrating the drive-side base part <NUM> in a thickness direction at the center thereof. The through hole <NUM> has a locking groove <NUM> on an inner peripheral surface thereof. One end portion of the first transmission shaft <NUM> is inserted into the through hole <NUM>. In this state, the locking groove <NUM> is engaged with the engaging part 432a of the first transmission shaft <NUM>. Therefore, both the first transmission shaft <NUM> and the drive-side base part <NUM> (the drive-side element <NUM>) are rotatable. It may be understood that the drive-side element <NUM> rotates on the basis of the power of the electric motor <NUM>.

The drive-side transmission part <NUM> is provided on one end face (surface on the + side in the X direction) of the drive-side base part <NUM>. The drive-side transmission part <NUM> is a substantially fan-shaped protrusion. The drive-side transmission part <NUM> has a first transmission surface <NUM> on one end face of the drive-side element <NUM> in a circumferential direction. The drive-side transmission part <NUM> has a second transmission surface <NUM> on the other end face of the drive-side element <NUM> in the circumferential direction.

The driven-side element <NUM> includes a driven-side base part <NUM> and a driven-side transmission part <NUM>.

The driven-side base part <NUM> may have, for example, a disk shape. The driven-side base part <NUM> has a through hole <NUM> penetrating the driven-side base part <NUM> in the thickness direction at the center thereof. The through hole <NUM> has a locking groove <NUM> on an inner peripheral surface thereof. One end portion of the second transmission shaft <NUM> is inserted into the through hole <NUM>. In this state, the locking groove <NUM> is engaged with the engaging part 433a of the second transmission shaft <NUM>. Therefore, both the second transmission shaft <NUM> and the driven-side base part <NUM> (the driven-side element <NUM>) are rotatable. It may be understood that the driven-side element <NUM> is connected to the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> to be described later.

The driven-side transmission part <NUM> is provided on one end face (surface on the - side in the X direction) of the driven-side base part <NUM>. The driven-side transmission part <NUM> is a substantially fan-shaped protrusion provided on one end face of the driven-side base part <NUM>. The driven-side transmission part <NUM> has a first transmission surface <NUM> on one end face of the driven-side element <NUM> in the circumferential direction. The driven-side transmission part <NUM> has a second transmission surface <NUM> on the other end face of the driven-side element <NUM> in the circumferential direction.

The drive-side element <NUM> and the driven-side element <NUM> as described above are disposed such that one end faces thereof face each other in the X direction. The drive-side transmission part <NUM> of the drive-side element <NUM> and the driven-side transmission part <NUM> of the driven-side element <NUM> can take a state (hereinafter, referred to as an "engaged state. ") of being engaged in a rotation direction (also referred to as a circumferential direction. ) of the drive-side element <NUM> and the driven-side element <NUM> and a state (hereinafter, referred to as a "disengaged state. ") of being separated in the rotation direction.

Note that in the assembled state illustrated in <FIG>, a gap 64a is provided between the drive-side transmission part <NUM> of the drive-side element <NUM> and the driven-side base part <NUM> of the driven-side element <NUM>. In addition, in the assembled state illustrated in <FIG>, a gap 64b is provided between the driven-side transmission part <NUM> of the driven-side element <NUM> and the drive-side base part <NUM> of the drive-side element <NUM>. That is, in the assembled state, the drive-side element <NUM> and the driven-side element <NUM> are not in contact with each other in the X direction. Such gaps 64a and 64b may eliminate sliding resistance between the drive-side element <NUM> and the driven-side element <NUM>.

In the engaged state, the drive-side element <NUM> and the driven-side element <NUM> rotate together. Such an engaged state corresponds to the transmission state of the coupling <NUM>, in which the drive-side element <NUM> and the driven-side element <NUM> rotate together. Specifically, in the engaged state, the rotation of one of the drive-side element <NUM> and the driven-side element <NUM> is transmitted to the other element, so the drive-side element <NUM> and the driven-side element <NUM> rotate together. Such an engaged state corresponds to the transmission state of the coupling <NUM> in which power can be transmitted between the drive-side element <NUM> and the driven-side element <NUM>.

On the other hand, in the disengaged state, only one of the drive-side element <NUM> and the driven-side element <NUM> rotates (idles) with respect to the drive-side element <NUM> and the driven-side element <NUM>. Such a disengaged state corresponds to a non-transmission state of the coupling <NUM> in which only one of the drive-side element <NUM> and the driven-side element <NUM> is rotatable.

The operation of the coupling <NUM> will be described together with the operation of the boom connecting mechanism and the operation of the cylinder connecting mechanism to be described later.

The second transmission shaft <NUM> is a shaft member, and has an engaging part 433a (see <FIG>) at one end portion (end portion on the - side in the X direction) of the outer peripheral surface thereof The engaging part 433a is, for example, a ridge extending in the axial direction of the second transmission shaft <NUM>.

One end portion (end portion on the - side in the X direction) of the second transmission shaft <NUM> is connected to the driven-side element <NUM> of the coupling <NUM>. The second transmission shaft <NUM> extends in the X direction and is inserted into the housing <NUM> (specifically, the second housing element <NUM>).

An end portion of the second transmission shaft <NUM> on the + side in the X direction protrudes to the + side in the X direction from the housing <NUM>. A position information detection device <NUM> to be described later is provided at an end portion of the second transmission shaft <NUM> on the + side in the X direction.

The position information detection device <NUM> detects information on the positions of the pair of cylinder connecting pins 454a and 454b and the pair of boom connecting pins 144a (the pair of boom connecting pins 144b may be used. The same applies hereinafter. ) based on the output (for example, the rotation of the output shaft) of the electric motor <NUM>. The information on the position may be, for example, a movement amount of the pair of cylinder connecting pins 454a and 454b or the pair of boom connecting pins 144a from a reference position (the position illustrated in <FIG> and <FIG>).

Specifically, the position information detection device <NUM> detects the information on the positions of the pair of cylinder connecting pins 454a and 454b in the engaged state (for example, the state illustrated in <FIG>) or the disengaged state (the state illustrated in <FIG>) between the pair of cylinder connecting pins 454a and 454b and the pair of cylinder pin receiving parts 141a of the boom element (for example, the tip boom element <NUM>).

In addition, the position information detection device <NUM> detects the information on the positions of the pair of boom connecting pins 144a in the engaged state (for example, the state illustrated in <FIG>) or the disengaged state (for example, the state illustrated in <FIG>) between the pair of boom connecting pins 144a and the pair of first boom pin receiving parts 142b (the pair of second boom pin receiving parts 142c may be used. The same applies hereinafter. ) of the boom element (for example, the intermediate boom element <NUM>).

The information on the positions of the pair of cylinder connecting pins 454a and 454b and the pair of boom connecting pins 144a and 144b detected in this manner is used for various controls of the actuator <NUM> including operation control of the electric motor <NUM>, for example.

The position information detection device <NUM> includes a detection unit 44a and a control unit 44b (see <FIG> and <FIG>).

The detection unit 44a is, for example, a rotary encoder, and outputs information (for example, a pulse signal and a code signal) corresponding to the rotation amount of the output shaft of the electric motor <NUM>. The 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 the 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 the reference point.

When the detection unit 44a is an absolute type rotary encoder, even when control unit 44b returns from the non-energized state to the energized state, the position information detection device <NUM> can detect the information on the positions of the pair of cylinder connecting pins 454a, 454b and the pair of boom connecting pins 144a.

The detection unit 44a may be provided on the output shaft of the electric motor <NUM>. In addition, the detection unit 44a 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>. Specifically, in the case of the present embodiment, the detection unit 44a is provided at an end portion of the second transmission shaft <NUM> on the + side in the X direction. In other words, in the case of the present embodiment, the detection unit 44a is provided at a stage (that is, the + side in the X direction) subsequent to the speed reducer <NUM>.

In the case of the present embodiment, the detection unit 44a outputs information corresponding to the rotation amount of the second transmission shaft <NUM>. In the case of the present embodiment, a rotary encoder capable of obtaining sufficient resolution with respect to a rotation number (rotation speed) of the second transmission shaft <NUM> is adopted as the detection unit 44a. Note that since a first toothless gear <NUM> of the cylinder connecting mechanism <NUM> and a second toothless gear <NUM> of the boom connecting mechanism <NUM>, which will be described later, are fixed to the transmission shaft <NUM>, the output information of the detection unit 44a is also information corresponding to the rotation amounts of the first toothless gear <NUM> and the second toothless gear <NUM>.

The detection unit 44a having the above configuration sends the detection value to the control unit 44b. The control unit 44b that has acquired the information calculates the information on the positions of the pair of cylinder connecting pins 454a and 454b or the pair of boom connecting pins 144a based on the acquired information. Then, the control unit 44b controls the electric motor <NUM> based on the calculation result.

The control unit 44b is, for example, an in-vehicle computer including an input terminal, an output terminal, a CPU, a memory, and the like. The control unit 44b calculates the information on the positions of the pair of cylinder connecting pins 454a and 454b or the boom connecting pin 144a based on the output of the detection unit 44a.

Specifically, for example, the control unit 44b calculates the information on the position using data (tables, maps, or the like) indicating a correlation between the output of the detection unit 44a and the information (for example, the movement amount from the reference position) on the positions of the pair of cylinder connecting pins 454a and 454b and the pair of boom connecting pins 144a.

When the output of the detection unit 44a is a code signal, the information on the position is calculated based on data (tables, maps, or the like) indicating a correlation between each code signal and the movement amount of the pair of cylinder connecting pins 454a and 454b and the pair of boom connecting pins 144a from the reference position.

The control unit 44b as described above is provided on the turning table <NUM>. However, the position of the control unit 44b is not limited to the turning table <NUM>. The control unit 44b may be provided, for example, in a case (not illustrated) in which the detection unit 44a is disposed.

Note that the position of the detection unit 44a is not limited to the position of the present embodiment. For example, the detection unit 44a may be disposed in front of the speed reducer <NUM> (that is, the - side in the X direction). That is, the detection unit 44a may acquire information to be sent to the control unit 44b based on the rotation of the electric motor <NUM> before being decelerated by the speed reducer <NUM>. The resolution of the detection unit 44a is higher in the configuration in which the detection unit 44a is disposed at the front stage of the speed reducer <NUM> than in the configuration in which the detection unit 44a is disposed at the rear stage of the speed reducer <NUM>.

The detection unit 44a is not limited to the above-described rotary encoder. For example, the detection unit 44a may be a limit switch. The limit switch is disposed at the stage subsequent to the speed reducer <NUM>. Such a limit switch mechanically operates based on the output of the electric motor <NUM>. Alternatively, the detection unit 44a may be a proximity sensor. The proximity sensor is disposed at the stage subsequent to the speed reducer <NUM>. In addition, the proximity sensor is disposed to face a member that rotates on the basis of the output of the electric motor <NUM>. Such a proximity sensor outputs a signal based on the distance from the rotating member. Then, the control unit 44b controls the operation of the electric motor <NUM> based on the output of the limit switch or the proximity sensor.

The cylinder connecting mechanism <NUM> corresponds to an example of an operating unit, operates based on power (that is, rotational motion) of the electric motor <NUM>, and performs a state transition between an extended state (also referred to as a first state. See <FIG> and <FIG>) and a retracted state (also referred to as a second state. See <FIG>).

In the extended state, the pair of cylinder connecting pins 454a and 454b to be described later and the pair of cylinder pin receiving parts 141a of the boom element (for example, the tip boom element <NUM>) are in the engaged state (also referred to as a state in which a cylinder pin is inserted. In the engaged state, the boom element and the cylinder member <NUM> are connected.

On the other hand, in the retracted state, the pair of cylinder connecting pins 454a and 454b and the pair of cylinder pin receiving parts 141a (see <FIG>) are in the separated state (the state illustrated in <FIG>, and also referred to as a pulled state of a cylinder pin. In the separated state, the boom element and the cylinder member <NUM> are in the disconnected state.

Hereinafter, a specific configuration of the cylinder connecting mechanism <NUM> will be described. As illustrated in <FIG>, the cylinder connecting mechanism <NUM> includes a first toothless gear <NUM>, a first rack bar <NUM>, a first gear mechanism <NUM>, a second gear mechanism <NUM>, a pair of cylinder connecting pins 454a and 454b, and a first urging mechanism <NUM>. Each of the elements <NUM>, <NUM>, <NUM>, and <NUM> corresponds to an example of a constituent member of the first drive mechanism.

In the case of the present embodiment, the pair of cylinder connecting pins 454a and 454b is incorporated in the cylinder connecting mechanism <NUM>. However, the pair of cylinder connecting pins 454a and 454b may be provided independently of the cylinder connecting mechanism <NUM>.

The first toothless gear <NUM> (also referred to as a switch gear. ) has a substantially disk shape. The first toothless gear <NUM> has a first tooth part 450a (see <FIG>) on a portion of an outer peripheral surface thereof. The first toothless gear <NUM> is externally fitted and fixed to the second transmission shaft <NUM> and rotates together with the second transmission shaft <NUM>.

Such a first toothless gear <NUM> constitutes a switch gear together with the second toothless gear <NUM> (see <FIG>) of the boom connecting mechanism <NUM>. The switch gear selectively transmits the power of the electric motor <NUM> to any one of the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM>.

Note that in the present embodiment, the first toothless gear <NUM> and the second toothless gear <NUM>, which are switch gears, are respectively incorporated in the cylinder connecting mechanism <NUM>, which is a first connecting mechanism, and the boom connecting mechanism <NUM>, which is a second connecting mechanism. However, the switch gear may be provided independently of the first connecting mechanism and the second connecting mechanism.

In the following description, when the cylinder connecting mechanism <NUM> transitions from the extended state (see <FIG>, <FIG>, and <FIG>) to the retracted state (see <FIG> and <FIG>), a rotation direction (direction of arrow F<NUM> in <FIG>) of the first toothless gear <NUM> is a "front side" in the rotation direction of the first toothless gear <NUM>.

On the other hand, the rotation direction of the first toothless gear <NUM> (direction of arrow F<NUM> in <FIG>) at the time of state transition from the retracted state to the extended state is a "rear side" in the rotation direction of the first toothless gear <NUM>.

Among the protrusions constituting the first tooth part 450a, the protrusion provided on the foremost side in the rotation direction of the first toothless gear <NUM> is a positioning tooth (not illustrated).

A first rack bar <NUM> moves in its longitudinal direction (also referred to as a Y direction. ) in accordance with the rotation of the first toothless gear <NUM>. The first rack bar <NUM> is located closest to a - side in the Y direction in the extended state (see <FIG> and <FIG>). On the other hand, the first rack bar <NUM> is located closest to a + side in the Y direction in the retracted state (see <FIG>).

When the state transitions from the extended state to the retracted state, if the first toothless gear <NUM> rotates forward in the rotation direction, the first rack bar <NUM> moves to the + side in the Y direction (also referred to as one side in the longitudinal direction.

On the other hand, when the state transitions from the retracted state to the extended state, if the first toothless gear <NUM> rotates backward in the rotation direction, the first rack bar <NUM> moves toward the - side in the Y direction (also referred to as the other side in the longitudinal direction. A specific configuration of first rack bar <NUM> will be described below.

The first rack bar <NUM> is, for example, a shaft member elongated in the Y direction, and is disposed between the first toothless gear <NUM> and the rod member <NUM>. In this state, the longitudinal direction of the first rack bar <NUM> coincides with the Y direction.

The first rack bar <NUM> has a first rack tooth part 451a (see <FIG>) on a surface closer to the first toothless gear <NUM> (also referred to as a + side in the Z direction. The first rack tooth part 451a meshes with the first tooth part 450a of the first toothless gear <NUM> only during the above-described state transition.

In the extended state illustrated in <FIG> and <FIG>, a first end face (not illustrated) of the first rack tooth part 451a on the + side in the Y direction abuts on the positioning tooth (not illustrated) of the first tooth part 450a of the first toothless gear <NUM> or faces the positioning tooth (not illustrated) in the Y direction with a slight gap interposed therebetween.

When the first toothless gear <NUM> rotates forward in the rotation direction in the extended state, the positioning tooth 450b presses the first end face toward the + side in the Y direction, and the first rack bar <NUM> moves toward the + side in the Y direction.

Then, the tooth part of the first tooth part 450a located behind the positioning tooth in the rotation direction meshes with the first rack tooth part 451a. As a result, the first rack bar <NUM> moves to the + side in the Y direction in accordance with the rotation of the first toothless gear <NUM>.

Note that when the first toothless gear <NUM> rotates backward in the rotation direction from the extended state illustrated in <FIG>, the first rack tooth part 451a and the first tooth part 450a of the first toothless gear <NUM> do not mesh with each other.

In addition, the first rack bar <NUM> has a second rack tooth part 451b and a third rack tooth part 451c (see <FIG>) on a surface on a side (also referred to as a - side in the Z direction. ) far from the first toothless gear <NUM>. The second rack tooth part 451b meshes with a first gear mechanism <NUM> to be described later. On the other hand, the third rack tooth part 451c meshes with a second gear mechanism <NUM> to be described later.

The first gear mechanism <NUM> includes a plurality of (<NUM> in the case of the present embodiment) gear elements 452a, 452b, and 452c (see <FIG>) each of which is a spur gear. Specifically, the gear element 452a meshes with the second rack tooth part 451b of the first rack bar <NUM> and the gear element 452b. In the extended state (see <FIG> and <FIG>), the gear element 452a meshes with the tooth part at the end portion on the + side in the Y direction or the portion close to the end portion in the second rack tooth part 451b of the first rack bar <NUM>.

The gear element 452b meshes with the gear element 452a and the gear element 452c.

The gear element 452c meshes with the gear element 452b and a pin-side rack tooth part 454c of one cylinder connecting pin 454a to be described later. In the extended state, the gear element 452c meshes with the end portion on the - side in the Y-direction in the pin-side rack tooth part 454c (see <FIG>) of one cylinder connecting pin 454a.

The second gear mechanism <NUM> includes a plurality of (in the case of the present embodiment, two) gear elements 453a and 453b (see <FIG>) each of which is a spur gear. Specifically, the gear element 453a meshes with the third rack tooth part 451c of the first rack bar <NUM> and the gear element 453b. In the extended state, the gear element 453a meshes with the end portion on the + side in the Y direction of the third rack tooth part 451c of the first rack bar <NUM>.

The gear element 453b meshes with the gear element 453a and a pin-side rack tooth part 454d (see <FIG>) of the other cylinder connecting pin 454b to be described later. In the extended state, the gear element 453b meshes with the end portion on the + side in the Y direction of the pin-side rack tooth part 454d of the other cylinder connecting pin 454b.

In the case of the present embodiment, the rotation direction of the gear element 452c of the first gear mechanism <NUM> is opposite to the rotation direction of the gear element 453b of the second gear mechanism <NUM>.

A central axis of each of the pair of cylinder connecting pins 454a and 454b coincides with the Y direction and is coaxial with each other. Hereinafter, in the description of the pair of cylinder connecting pins 454a and 454b, the tip portion is an end portion on a side far from each other, and the proximal end portion is an end portion on a side close to each other.

Each of the pair of cylinder connecting pins 454a and 454b has pin-side rack tooth parts 454c and 454d (see <FIG>) on the outer peripheral surface thereof. The pin-side rack tooth part 454c of one (also referred to as the + side in the Y direction. ) cylinder connecting pin 454a meshes with the gear element 452c of the first gear mechanism <NUM>.

One cylinder connecting pin 454a moves in its own axial direction (that is, the Y direction) as the gear element 452c in the first gear mechanism <NUM> rotates. Specifically, one cylinder connecting pin 454a moves to the + side in the Y direction (also referred to as a second direction. ) when the state transitions from the retracted state to the extended state. On the other hand, one cylinder connecting pin 454a moves to the - side in the Y direction (also referred to as a first direction. ) when the state transitions from the extended state to the retracted state.

The pin-side rack tooth part 454d of the other (also referred to as the - side in the "Y direction. ") cylinder connecting pin 454b meshes with the gear element 453b of the second gear mechanism <NUM>. The other cylinder connecting pin 454b moves in its own axial direction (that is, the Y direction) as the gear element 453b in the second gear mechanism <NUM> rotates.

Specifically, the other cylinder connecting pin 454b moves to the - side in the Y direction (also referred to as a second direction. ) when the state transitions from the retracted state to the extended state. On the other hand, the other cylinder connecting pin 454b moves to the + side in the Y direction (also referred to as a first direction. ) when the state transitions from the extended state to the retracted state. That is, in the above-described state transition, the pair of cylinder connecting pins 454a and 454b moves in directions opposite to each other in the Y direction.

The pair of cylinder connecting pins 454a and 454b are respectively inserted into the through holes 400a and 400b of the first housing element <NUM>. In this state, the tip portions of the pair of cylinder connecting pins 454a and 454b protrude to the outside of the first housing element <NUM>.

A first urging mechanism <NUM> automatically returns the cylinder connecting mechanism <NUM> to the extended state when the electric motor <NUM> is in the non-energized state in the retracted state of the cylinder connecting mechanism <NUM>. Therefore, the first urging mechanism <NUM> urges the pair of cylinder connecting pins 454a and 454b in directions away from each other. Note that the first urging mechanism <NUM> may directly apply a force to the cylinder connecting pins 454a and 454b, or may apply a force via another member. In addition, in an example which does not form part of the claimed invention, the first urging mechanism <NUM> may be omitted. In this case, the cylinder connecting mechanism <NUM> may make a state transition from the retracted state to the extended state based on the power of the electric motor <NUM>.

Specifically, the first urging mechanism <NUM> includes a pair of coil springs 455a and 455b (see <FIG>). Each of the pair of coil springs 455a and 455b urges the pair of cylinder connecting pins 454a and 454b toward the tip side. Each of the pair of coil springs 455a and 455b corresponds to an example of a first urging member.

When the brake mechanism <NUM> operates, the cylinder connecting mechanism <NUM> does not automatically return.

An example of the operation of the above-described cylinder connecting mechanism <NUM> will be briefly described with reference to <FIG> are schematic diagrams for describing the operation of the cylinder connecting mechanism <NUM>. Further, in addition to the description of the operation of the cylinder connecting mechanism <NUM>, the operation of the coupling <NUM> will be described with reference to <FIG> and <FIG>. Note that <FIG> and <FIG> are schematic diagrams of the coupling <NUM> when viewed from the - side in the X direction.

<FIG> is a schematic diagram illustrating an extended state of the cylinder connecting mechanism <NUM> and an engaged state between the pair of cylinder connecting pins 454a and 454b and the pair of cylinder pin receiving parts 141a of the tip boom element <NUM>. <FIG> is a schematic diagram illustrating a state in the middle of the state transition of the cylinder connecting mechanism <NUM> from the extended state to the retracted state. Furthermore, <FIG> is a schematic diagram illustrating a retracted state of the cylinder connecting mechanism <NUM> and a separated state between the pair of cylinder connecting pins 454a and 454b and the pair of cylinder pin receiving parts 141a of the tip boom element <NUM>.

The cylinder connecting mechanism <NUM> makes a state transition between an extended state (see <FIG>, <FIG>, and <FIG>) and a retracted state (see <FIG> and <FIG>) based on the power (that is, rotational motion) of the electric motor <NUM>. Hereinafter, the operation of each unit when the cylinder connecting mechanism <NUM> transitions from the extended state to the retracted state will be described with reference to <FIG>.

Note that in <FIG>, the first toothless gear <NUM> and the second toothless gear <NUM> are schematically illustrated as an integrated toothless gear. Hereinafter, for convenience of description, the integrated toothless gear will be described as the first toothless gear <NUM>. In addition, in <FIG>, the lock mechanism <NUM> to be described later is omitted.

When the cylinder connecting mechanism <NUM> transitions from the extended state to the retracted state, the power of the electric motor <NUM> is transmitted to the pair of cylinder connecting pins 454a and 454b through the following first path and second path.

The first path is a path of the first toothless gear <NUM> → the first rack bar <NUM> → the first gear mechanism <NUM> → one cylinder connecting pin 454a.

On the other hand, the second path is a path of the first toothless gear <NUM> → the first rack bar <NUM> → the second gear mechanism <NUM> → the other cylinder connecting pin 454b.

Specifically, when the output shaft of the electric motor <NUM> rotates in the first direction, the drive-side element <NUM> of the coupling <NUM> rotates in the first direction (direction of arrow A6a in <FIG>) via the speed reducer <NUM> and the first transmission shaft <NUM>. Note that the positions of the drive-side element <NUM> and the driven-side element <NUM> illustrated in <FIG> are defined as neutral positions in the coupling <NUM>. The neutral position in the coupling <NUM> means a state in which the drive-side element <NUM> and the driven-side element <NUM> are not engaged. Therefore, the position of the drive-side element <NUM> corresponding to the neutral position of the coupling <NUM> is not limited to the position in <FIG>.

When the electric motor <NUM> rotates in the first direction, first, only the drive-side element <NUM> rotates. At this time, the driven-side element <NUM> stops. Then, when the drive-side element <NUM> rotates to the position of <FIG> with the rotation of the electric motor <NUM>, the first transmission surface <NUM> of the drive-side element <NUM> abuts on the first transmission surface <NUM> of the driven-side element <NUM>. In this state, the drive-side element <NUM> and the driven-side element <NUM> are engaged. Note that the state illustrated in <FIG> corresponds to an example of the non-transmission state of the coupling <NUM>.

When the electric motor <NUM> further rotates from the state of <FIG>, both the drive-side element <NUM> and the driven-side element <NUM> rotate in the first direction. That is, the rotation of the drive-side element <NUM> is transmitted to the driven-side element <NUM>. Note that the state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

As the drive-side element <NUM> and the driven-side element <NUM> rotate as described above, the first toothless gear <NUM> rotates on the front side in the rotation direction (direction of arrow F<NUM> in <FIG>) in the first path and the second path. Note that the direction of arrow A6a in <FIG> corresponds to the direction of arrow F<NUM> in <FIG>.

In the first path and the second path, when the first toothless gear <NUM> rotates forward in the rotation direction, the first rack bar <NUM> moves to the + side in the Y direction (the right side in <FIG>) according to the rotation.

Then, in the first path, when the first rack bar <NUM> moves to the + side in the Y direction, one cylinder connecting pin 454a moves to the - side in the Y direction (the left side in <FIG>) via the first gear mechanism <NUM>.

On the other hand, when the first rack bar <NUM> moves to the + side in the Y direction in the second path, the other cylinder connecting pin 454b moves to the + side in the Y direction via the second gear mechanism <NUM>. That is, at the time of the state transition from the extended state to the retracted state, one cylinder connecting pin 454a and the other cylinder connecting pin 454b move in directions approaching each other.

The position information detection device <NUM> detects that the pair of cylinder connecting pins 454a and 454b is separated from the pair of cylinder pin receiving parts 141a of the tip boom element <NUM> and moved to a predetermined position (for example, the position illustrated in <FIG> and <FIG>). Then, based on the detection result, the control unit 44b stops the operation of the electric motor <NUM>.

In a state where the pair of cylinder connecting pins 454a and 454b has moved to predetermined positions, the drive-side element <NUM> and the driven-side element <NUM> are in a state illustrated in <FIG>. In this state, the driven-side element <NUM> stops by being restricted from rotating in the first direction by the stopper 63a. When the driven-side element <NUM> stops, the drive-side element <NUM> also stops. Then, by turning the electric motor <NUM> to the OFF state and turning the brake mechanism <NUM> to the ON state, the retracted state of the cylinder connecting mechanism <NUM> is maintained. The coupling <NUM> is maintained in the state illustrated in <FIG>. Note that the stopper 63a is not necessarily provided on the coupling <NUM>. In addition, the stopper 63a may not be a member that directly abuts on the driven-side element <NUM> to prevent the rotation of the driven-side element <NUM> in the direction of the arrow A6a. That is, the stopper 63a may be a member that prevents the rotation of the driven-side element <NUM> in the direction of the arrow A6a as a result of the stopper 63a abutting on a member other than the driven-side element <NUM>.

Next, the operations of the cylinder connecting mechanism <NUM> and the coupling <NUM> when the cylinder connecting mechanism <NUM> transitions from the retracted state to the extended state will be described with reference to <FIG> and <FIG>.

When the cylinder connecting mechanism <NUM> transitions from the retracted state to the extended state, the cylinder connecting mechanism <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG>.

First, in the state illustrated in <FIG>, the brake mechanism <NUM> is set to the OFF state while maintaining the OFF state of the electric motor <NUM>. Then, based on the urging force of the first urging mechanism <NUM>, one cylinder connecting pin 454a and the other cylinder connecting pin 454b move in directions away from each other. As one cylinder connecting pin 454a and the other cylinder connecting pin 454b move, the first toothless gear <NUM> rotates in the direction of the arrow F<NUM> in <FIG>.

Then, the rotation of the first toothless gear <NUM> is transmitted to the driven-side element <NUM> of the coupling <NUM> via the second transmission shaft <NUM>, and the driven-side element <NUM> rotates in a direction of arrow A6b in <FIG>. The rotation of the driven-side element <NUM> is transmitted to the drive-side element <NUM>, and the drive-side element <NUM> and the driven-side element <NUM> rotate in the direction of the arrow A6b in <FIG>. Note that the direction of arrow A6b in <FIG> corresponds to the direction of arrow F<NUM> in <FIG>. In addition, note that the state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

The driven-side element <NUM> passes through the position illustrated in <FIG> and stops at the position illustrated in <FIG> while being restricted in rotation by the stopper 63b. When the coupling <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG>, the cylinder connecting mechanism <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG> through the state illustrated in <FIG>. Note that the stopper 63b is not necessarily provided on the coupling <NUM>. In addition, the stopper 63b may not be a member that directly abuts on the driven-side element <NUM> to prevent the rotation of the driven-side element <NUM> in the direction of the arrow A6b. That is, the stopper 63b may be a member that prevents the rotation of the driven-side element <NUM> in the direction of the arrow A6b as a result of the stopper 63b abutting on a member other than the driven-side element <NUM>.

It may be understood that the state of the coupling <NUM> illustrated in <FIG> corresponds to the state of the cylinder connecting mechanism <NUM> illustrated in <FIG>. In addition, it may be understood that the position of the driven-side element <NUM> illustrated in <FIG> is the position of the driven-side element <NUM> in the extended state of the cylinder connecting mechanism <NUM>.

When the driven-side element <NUM> stops at the position illustrated in <FIG>, the drive-side element <NUM> further rotates in the direction of the arrow A6b in <FIG> based on an inertial force of the electric motor <NUM>. Then, the drive-side element <NUM> stops in the range indicated by arrow Ar in <FIG> based on a frictional resistance accompanying the rotation of the drive-side element <NUM>. Note that the state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

The stop position of the drive-side element <NUM> is preferably a position (for example, the position illustrated in <FIG>) where a second transmission surface <NUM> of the drive-side element <NUM> does not abut on a second transmission surface <NUM> of the driven-side element <NUM>. Note that even when the second transmission surface <NUM> of the drive-side element <NUM> abuts on the second transmission surface <NUM> of the driven-side element <NUM>, it is sufficient that the driven-side element <NUM> does not rotate in the direction of the arrow A6b from the position illustrated in <FIG>. In addition, note that the state illustrated in <FIG> corresponds to an example of the non-transmission state of the coupling <NUM>.

The reason for adopting the above-described configuration will be described. In the insertion operation of the cylinder connecting mechanism <NUM>, when the drive-side element <NUM> overruns more than a predetermined amount based on the inertial force of the electric motor <NUM>, the drive-side element <NUM> abuts on the driven-side element <NUM> and rotates the driven-side element <NUM> in the direction of the arrow A6b in <FIG>. As a result, unintended pulling operation of the boom connecting mechanism <NUM> may occur.

Therefore, in the case of the present embodiment, in the insertion operation of the cylinder connecting mechanism <NUM>, the overrun of the drive-side element <NUM> based on the inertial force of the electric motor <NUM> is restricted to a range smaller than the predetermined amount by adopting the configuration in which only the drive-side element <NUM> rotates and stops by the frictional resistance. As a result, in the insertion operation of the cylinder connecting mechanism <NUM>, an unintended pulling operation of the boom connecting mechanism <NUM> is prevented from occurring. Note that the predetermined amount related to the overrun of the drive-side element <NUM> may be understood as a range in which the drive-side element <NUM> does not overrun and abut on the driven-side element <NUM> at the neutral position in the insertion operation of the cylinder connecting mechanism <NUM>.

Note that when the boom connecting mechanism <NUM> transitions from the extended state to the retracted state, the drive-side element <NUM> rotates in the direction of arrow A6b from the position illustrated in <FIG> based on the power of the electric motor <NUM>. Then, as illustrated in <FIG>, the drive-side element <NUM> abuts on the driven-side element <NUM>. Thereafter, as illustrated in <FIG>, the drive-side element <NUM> and the driven-side element <NUM> rotate in the direction of the arrow A6b. The operation of the boom connecting mechanism <NUM> will be described later.

The boom connecting mechanism <NUM> corresponds to an example of the operating unit, and transitions between the extended state (also referred to as a first state. See <FIG> and <FIG>) and the retracted state (also referred to as a second state. See <FIG>) based on the rotation of the electric motor <NUM>.

In the extended state, the boom connecting mechanism <NUM> takes either the engaged state or the disengaged state with respect to the boom connecting pin (for example, a pair of boom connecting pins 144a).

The boom connecting mechanism <NUM> disengages the boom connecting pin from the boom element by transitioning from the extended state to the retracted state while being engaged with the boom connecting pin.

In addition, the boom connecting mechanism <NUM> engages the boom connecting pin with the boom element by transitioning from the retracted state to the extended state while being engaged with the boom connecting pin.

Hereinafter, a specific configuration of the boom connecting mechanism <NUM> will be described. As illustrated in <FIG>, the boom connecting mechanism <NUM> includes the second toothless gear <NUM>, the pair of second rack bars 461a and 461b, a synchronous gear <NUM> (see <FIG>), and a second urging mechanism <NUM>. Each of the elements <NUM>, 461a, 461b, and <NUM> corresponds to an example of a constituent member of the second drive mechanism. In addition, the pair of boom connecting pins 144a and 144b also corresponds to an example of a constituent member of the second drive mechanism.

The second toothless gear <NUM> (Also referred to as a switch gear. ) has a substantially disk shape, and has a second tooth part 460a on a portion of the outer peripheral surface thereof in the circumferential direction.

The second toothless gear <NUM> is externally fitted and fixed to the second transmission shaft <NUM> on the + side in the X direction with respect to the first toothless gear <NUM>, and rotates together with the second transmission shaft <NUM>. Note that the second toothless gear <NUM> may be, for example, a toothless gear integrated with the first toothless gear <NUM> as in the schematic diagrams illustrated in <FIG>.

Hereinafter, the rotation direction of the second toothless gear <NUM> (the direction of the arrow F<NUM> in <FIG>) when the boom connecting mechanism <NUM> transitions from the extended state (see <FIG> and <FIG>) to the retracted state (see <FIG>) is the "front side " in the rotation direction of the second toothless gear <NUM>.

On the other hand, the rotation direction of the second toothless gear <NUM> (the direction of the arrow F<NUM> in <FIG>) when the boom connecting mechanism <NUM> transitions from the retracted state to the extended state is the "rear side" in the rotation direction of the second toothless gear <NUM>.

Among the protrusions constituting the second tooth part 460a, the protrusion provided on the foremost side in the rotation direction of the second toothless gear <NUM> is the positioning tooth 460b (see <FIG>).

Note that <FIG> is a view of the pin moving module <NUM> as viewed from the + side in the X direction. Therefore, in the case of the present embodiment, the front-rear direction in the rotation direction of the second toothless gear <NUM> is opposite to the front-rear direction in the rotation direction of the first toothless gear <NUM>.

That is, the rotation direction of the second toothless gear <NUM> when the boom connecting mechanism <NUM> transitions from the extended state to the retracted state is opposite to the rotation direction of the first toothless gear <NUM> when the cylinder connecting mechanism <NUM> transitions from the extended state to the retracted state.

Each of the pair of second rack bars 461a and 461b moves in the Y direction (also referred to as an axial direction. ) along with the rotation of the second toothless gear <NUM>. One second rack bars 461a (also referred to as the + side in the X direction. ) and the other second rack bars 461b (also referred to as the - side in the X direction. ) move in opposite directions in the Y direction.

One second rack bars 461a is located closest to the - side in the Y direction in the extended state. The other second rack bar 461b is located closest to the + side in the Y direction in the extended state.

In addition, one second rack bar 461a is located closest to the + side in the Y direction in the retracted state. The other second rack bar 461b is located closest to the - side in the Y direction in the retracted state.

Note that the movement of one second rack bars 461a toward the + side in the Y direction and the movement of the other second rack bar 461b toward the - side in the Y direction are restricted by, for example, abutting on a stopper surface <NUM> (see <FIG>) provided on the housing <NUM>.

Hereinafter, specific configurations of the pair of second rack bars 461a and 461b will be described below. Each of the pair of second rack bars 461a and 461b is, for example, a shaft member long in the Y direction, and is disposed in parallel to each other. Each of the pair of second rack bars 461a and 461b is disposed on the + side in the Z direction with respect to the first rack bar <NUM>. In addition, the pair of second rack bars 461a and 461b is disposed around the synchronous gear <NUM> to be described later in the X direction. The longitudinal direction of each of the pair of second rack bars 461a and 461b coincides with the Y direction.

Each of the pair of second rack bars 461a and 461b has synchronization rack tooth parts 461e and 461f (see <FIG>) on side surfaces facing each other in the X direction. Each of the synchronization rack tooth parts 461e and 461f meshes with the synchronous gear <NUM>.

When the synchronous gear <NUM> rotates, one second rack bar 461a and the other second rack bar 461b move in opposite directions in the Y direction.

Each of the pair of second rack bars 461a and 461b has locking claw parts <NUM> and <NUM> (also referred to as a locking part. See <FIG>) at the tip portions thereof. Such locking claw parts <NUM> and <NUM> are engaged with the pin-side receiving parts 144c (see <FIG>) provided in the boom connecting pins 144a and 144b when the boom connecting pins 144a and 144b are moved.

One second rack bar 461a has a driving rack tooth part 461c (see <FIG>) on a first side surface (side surface close to the second toothless gear <NUM>) of the second toothless gear <NUM>. The driving rack tooth part 461c meshes with the second tooth part 460a of the second toothless gear <NUM>.

In the extended state (see <FIG>), a first end face 461d (end face on the + side in the Y direction) of the driving rack tooth part 461c abuts on the positioning tooth 460b in the second tooth part 460a of the second toothless gear <NUM> or faces the positioning tooth 460b in the Y direction with a slight gap interposed therebetween.

When the second toothless gear <NUM> rotates forward in the rotation direction from the extended state, the positioning tooth 460b presses the first end face 461d toward the + side in the Y direction. With such pressing, one second rack bar 461a moves to the + side in the Y direction.

When one second rack bars 461a moves to the + side in the Y direction, the synchronous gear <NUM> rotates, and the other second rack bar 461b moves to the - side in the Y direction (that is, the side opposite to one second rack bar 461a).

The second urging mechanism <NUM> automatically returns the boom connecting mechanism <NUM> to the extended state when the electric motor <NUM> is in the non-energized state in the retracted state of the boom connecting mechanism <NUM>. Note that when the brake mechanism <NUM> is in operation, the boom connecting mechanism <NUM> is not automatically returned. In addition, in an example which does not form part of the claimed invention, the second urging mechanism <NUM> may be omitted. In this case, the boom connecting mechanism <NUM> may transition from the retracted state to the extended state based on the power of the electric motor <NUM>.

Thus, the second urging mechanism <NUM> urges the pair of second rack bars 461a and 461b in directions away from each other. Specifically, the second urging mechanism <NUM> includes a pair of coil springs 463a and 463b (see <FIG>). The pair of coil springs 463a and 463b urges the proximal end portions of the pair of second rack bars 461a and 461b toward the tip side. The pair of coil springs 463a and 463b corresponds to an example of a second urging member.

An example of the operation of the above-described boom connecting mechanism <NUM> will be briefly described with reference to <FIG> are schematic diagrams for describing the operation of the boom connecting mechanism <NUM>. In addition, in addition to the description of the operation of the boom connecting mechanism <NUM>, the operation of the coupling <NUM> will be described with reference to <FIG> and <FIG>. Note that <FIG> and <FIG> are schematic diagrams of the coupling <NUM> when viewed from the - side in the X direction.

<FIG> is a schematic diagram illustrating an extended state of the boom connecting mechanism <NUM> and an engaged state between the pair of boom connecting pins 144a and the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM>. <FIG> is a schematic diagram illustrating a state in the middle of the state transition of the boom connecting mechanism <NUM> from the extended state to the retracted state. Further, <FIG> is a schematic diagram illustrating the retracted state of the boom connecting mechanism <NUM> and the separated state between the pair of boom connecting pins 144a and the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM>.

The above-described boom connecting mechanism <NUM> makes the state transition between an extended state (see <FIG>) and a retracted state (see <FIG>) based on the power (that is, rotational motion) of the electric motor <NUM>. Hereinafter, the operation of each unit when the boom connecting mechanism <NUM> transitions from the extended state to the retracted state will be described with reference to <FIG>.

Note that in <FIG>, the first toothless gear <NUM> and the second toothless gear <NUM> are schematically illustrated as the integrated toothless gear. Hereinafter, for convenience of description, the integrated toothless gear will be described as the second toothless gear <NUM>. In addition, in <FIG>, the lock mechanism <NUM> to be described later is omitted.

When the boom connecting mechanism <NUM> transitions from the extended state to the retracted state, the power (that is, rotational motion) of the electric motor <NUM> is transmitted through the path of the second toothless gear <NUM> → one second rack bar 461a → the synchronous gear <NUM> → the other second rack bar 461b.

Specifically, when the output shaft of the electric motor <NUM> rotates in the second direction, the drive-side element <NUM> of the coupling <NUM> rotates in the second direction (the direction of the arrow A6b in <FIG>) via the speed reducer <NUM> and the first transmission shaft <NUM>. Note that the position illustrated in <FIG> is the neutral position of the coupling <NUM>.

When the electric motor <NUM> rotates in the second direction, first, only the drive-side element <NUM> rotates. At this time, the driven-side element <NUM> stops. Then, when the drive-side element <NUM> rotates to the position of <FIG> with the rotation of the electric motor <NUM>, the second transmission surface <NUM> of the drive-side element <NUM> abuts on the second transmission surface <NUM> of the driven-side element <NUM>. In this state, the drive-side element <NUM> and the driven-side element <NUM> are engaged. Note that the state illustrated in <FIG> corresponds to an example of the non-transmission state of the coupling <NUM>.

When the electric motor <NUM> further rotates from the state of <FIG>, both the drive-side element <NUM> and the driven-side element <NUM> rotate in the second direction. That is, the rotation of the drive-side element <NUM> is transmitted to the driven-side element <NUM>. The state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

As the drive-side element <NUM> and the driven-side element <NUM> rotate as described above, the second toothless gear <NUM> rotates forward in the rotation direction (the direction of the arrow F<NUM> in <FIG> and <FIG>). Note that the direction corresponds to the direction of the arrow A6b in <FIG> and the direction of arrow F<NUM> in <FIG>.

When the second toothless gear <NUM> rotates forward in the rotation direction, one second rack bar 461a moves to the + side in the Y direction (the right side in <FIG>) according to the rotation.

Then, the synchronous gear <NUM> rotates according to the movement of one second rack bar 461a toward the + side in the Y direction. In accordance with the rotation of the synchronous gear <NUM>, the other second rack bar 461b moves to the - side in the Y direction (the left side in <FIG>).

When the state transitions from the extended state to the retracted state while the pair of second rack bars 461a and 461b is engaged with the pair of boom connecting pins 144a, the pair of boom connecting pins 144a is separated from the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM> (see <FIG>).

The position information detection device <NUM> detects that the pair of boom connecting pins 144a is separated from the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM> and moved to a predetermined position (for example, positions illustrated in <FIG> and <FIG>). Then, based on the detection result, the control unit 44b stops the operation of the electric motor <NUM>.

In a state where the pair of boom connecting pins 144a has moved to the predetermined position, the drive-side element <NUM> and the driven-side element <NUM> are in the state illustrated in <FIG>. In this state, the rotation of the driven-side element <NUM> in the second direction is restricted and stops by the stopper 63c. When the driven-side element <NUM> stops, the drive-side element <NUM> also stops. Then, by turning off the electric motor <NUM> and turning on the brake mechanism <NUM>, the retracted state of the boom connecting mechanism <NUM> is maintained. The coupling <NUM> is maintained in the state illustrated in <FIG>.

Note that in the case of the present embodiment, the pulled state of the cylinder connecting pin and the pulled state of the boom connecting pin are prevented from being simultaneously realized in one boom element (for example, the tip boom element <NUM>).

For this reason, the state transition of the cylinder connecting mechanism <NUM> and the state transition of the boom connecting mechanism <NUM> are prevented from simultaneously occurring.

Specifically, when the first tooth part 450a of the first toothless gear <NUM> meshes with the first rack tooth part 451a of the first rack bar <NUM> in the cylinder connecting mechanism <NUM>, the second tooth part 460a of the second toothless gear <NUM> does not mesh with the driving rack tooth part 461c of one second rack bar 461a in the boom connecting mechanism <NUM>.

In addition, when the second tooth part 460a of the second toothless gear <NUM> meshes with the driving rack tooth part 461c of one second rack bar 461a in the boom connecting mechanism <NUM>, the first tooth part 450a of the first toothless gear <NUM> does not mesh with the first rack tooth part 451a of the first rack bar <NUM> in the cylinder connecting mechanism <NUM>.

Next, the operations of the boom connecting mechanism <NUM> and the coupling <NUM> when the boom connecting mechanism <NUM> transitions from the retracted state to the extended state will be described with reference to <FIG> and <FIG>.

When the boom connecting mechanism <NUM> transitions from the retracted state to the extended state, the boom connecting mechanism <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG>.

First, in the state illustrated in <FIG>, the brake mechanism <NUM> is set to the OFF state while maintaining the OFF state of the electric motor <NUM>. Then, based on the urging force of the second urging mechanism <NUM>, the pair of boom connecting pins 144a moves in directions away from each other. With such movement of the pair of boom connecting pins 144a, the second toothless gear <NUM> rotates in the direction of the arrow F<NUM> in <FIG>.

Then, the rotation of the second toothless gear <NUM> is transmitted to the driven-side element <NUM> of the coupling <NUM> via the second transmission shaft <NUM>, and the driven-side element <NUM> rotates in the direction of the arrow A6a in <FIG>. The rotation of the driven-side element <NUM> is transmitted to the drive-side element <NUM>, and the drive-side element <NUM> and the driven-side element <NUM> rotate in the direction of the arrow A6a in <FIG>. Note that the direction of the arrow A6a in <FIG> corresponds to the direction of the arrow F<NUM> in <FIG>. In addition, note that the state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

The driven-side element <NUM> passes through the position illustrated in <FIG> and stops at the position illustrated in <FIG> while being restricted in rotation by the stopper 63d. When the coupling <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG>, the boom connecting mechanism <NUM> transitions from the state illustrated in <FIG> to the state illustrated in <FIG> through the state illustrated in <FIG>. Note that the state illustrated in <FIG> corresponds to an example of the transmission state of the coupling <NUM>.

It may be understood that the state of the coupling <NUM> illustrated in <FIG> correspond to the state of the boom connecting mechanism <NUM> illustrated in <FIG>. In addition, it may be understood that the position of the driven-side element <NUM> illustrated in <FIG> is the position of the driven-side element <NUM> in the extended state of the boom connecting mechanism <NUM>.

When the driven-side element <NUM> stops at the position illustrated in <FIG>, the drive-side element <NUM> further rotates in the direction of the arrow A6a in <FIG> based on the inertial force of the electric motor <NUM>. Then, the drive-side element <NUM> stops in the range indicated by arrow Ar in <FIG> based on a frictional resistance accompanying the rotation of the drive-side element <NUM>.

The stop position of the drive-side element <NUM> is preferably a position where the first transmission surface <NUM> of the drive-side element <NUM> does not abut on the first transmission surface <NUM> of the driven-side element <NUM> (for example, the position illustrated in <FIG>). Note that even when the first transmission surface <NUM> of the drive-side element <NUM> abuts on the first transmission surface <NUM> of the driven-side element <NUM>, it is sufficient that the driven-side element <NUM> does not rotate in the direction of the arrow A6a from the position illustrated in <FIG>. The state illustrated in <FIG> corresponds to an example of the non-transmission state of the coupling <NUM>.

The reason for adopting the above-described configuration will be described. In the insertion operation of the boom connecting mechanism <NUM>, when the drive-side element <NUM> overruns by more than a predetermined amount based on the inertial force of the electric motor <NUM>, the drive-side element <NUM> abuts on the driven-side element <NUM> and rotates the driven-side element <NUM> in the direction of the arrow A6a in <FIG>. As a result, the unintended pulling operation of the cylinder connecting mechanism <NUM> may occur.

Therefore, in the case of the present embodiment, in the insertion operation of the boom connecting mechanism <NUM>, the overrun of the drive-side element <NUM> based on the inertial force of the electric motor <NUM> is restricted to a range smaller than the predetermined amount by adopting the configuration in which only the drive-side element <NUM> rotates and stops by the frictional resistance. As a result, the unintended pulling operation of the cylinder connecting mechanism <NUM> is prevented from occurring in the insertion operation of the boom connecting mechanism <NUM>. Note that the predetermined amount related to the overrun of the drive-side element <NUM> may be understood as a range in which the drive-side element <NUM> does not overrun and abut on the driven-side element <NUM> at the neutral position in the insertion operation of the cylinder connecting mechanism <NUM>.

Note that when the cylinder connecting mechanism <NUM> transitions from the extended state to the retracted state, the drive-side element <NUM> rotates in the direction of the arrow A6a from the position illustrated in <FIG> based on the power of the electric motor <NUM>. Then, as illustrated in <FIG>, the drive-side element <NUM> abuts on the driven-side element <NUM>. Thereafter, as illustrated in <FIG>, the drive-side element <NUM> and the driven-side element <NUM> rotate in the direction of the arrow A6a. The operation of the cylinder connecting mechanism <NUM> is as described above.

However, the operating unit is not limited to the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM>. The operating unit may be various mechanisms that operate based on the power of the electric drive source.

As described above, in the actuator <NUM> according to the present embodiment, the pulled state of the cylinder connecting pin and the pulled state of the boom connecting pin are not simultaneously realized in one boom element (for example, the tip boom element <NUM>) based on the configurations of the boom connecting mechanism <NUM> and the cylinder connecting mechanism <NUM>. Such a configuration prevents simultaneous operation of the boom connecting mechanism <NUM> and the cylinder connecting mechanism <NUM> based on the power of the electric motor <NUM>.

In addition to such a configuration, the actuator <NUM> according to the present embodiment includes the lock mechanism <NUM> that prevents the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> from simultaneously transitioning when an external force other than the electric motor <NUM> acts on the cylinder connecting mechanism <NUM> (for example, first rack bar <NUM>) or the boom connecting mechanism <NUM> (for example, second rack bar 461a).

Such a lock mechanism <NUM> blocks the operation of one of the boom connecting mechanism <NUM> and the cylinder connecting mechanism <NUM> in a state where the other connecting mechanism is operating. Hereinafter, a specific structure of the lock mechanism <NUM> will be described with reference to <FIG>. Note that <FIG> are schematic diagrams for describing the structure of the lock mechanism <NUM>.

In addition, in <FIG>, the first toothless gear <NUM> of the cylinder connecting mechanism <NUM> and the second toothless gear <NUM> of the boom connecting mechanism <NUM> are integrally formed to constitute the integrated toothless gear <NUM> (also referred to as a switch gear. The integrated toothless gear <NUM> has a substantially disk shape, and has a tooth part 49a on a portion of the outer peripheral surface. The structure of the other portions is the same as the structure of the present embodiment described above.

The lock mechanism <NUM> includes a first protrusion <NUM>, a second protrusion <NUM>, and a cam member <NUM> (also referred to as a lock-side rotating member.

The first protrusion <NUM> is provided integrally with the first rack bar <NUM> of the cylinder connecting mechanism <NUM>. Specifically, the first protrusion <NUM> is provided at a position adjacent to the first rack tooth part 451a of the first rack bar <NUM>.

The second protrusion <NUM> is provided integrally with one second rack bar 461a of the boom connecting mechanism <NUM>. Specifically, the second protrusion <NUM> is provided at a position adjacent to the driving rack tooth part 461c of one second rack bars 461a.

The cam member <NUM> is a plate-shaped member having a substantially crescent shape. Such a cam member <NUM> has a first cam receiving part 472a at one end thereof in the circumferential direction. On the other hand, the cam member <NUM> has a second cam receiving part 472b at the other end thereof in the circumferential direction.

For example, the cam member <NUM> may be externally fitted and fixed to the second transmission shaft <NUM> at the position shifted in the X direction from the position where the integrated toothless gear <NUM> is externally fitted and fixed. Note that in the present embodiment, the cam member <NUM> is externally fitted and fixed between the first toothless gear <NUM> and the second toothless gear <NUM>. That is, the cam member <NUM> and the integrated toothless gear <NUM> are provided coaxially. Such a cam member <NUM> rotates together with the second transmission shaft <NUM>. Therefore, the cam member <NUM> rotates about the central axis of the transmission shaft <NUM> together with the integrated toothless gear <NUM>.

Note that the cam member <NUM> may be integrated with the integrated toothless gear <NUM>. In addition, in the present embodiment, the cam member <NUM> may be integrated with at least one of the first toothless gear <NUM> and the second toothless gear <NUM>.

As illustrated in <FIG> and <FIG>, in a state where the tooth part 49a (also the second tooth part 460a of the second toothless gear <NUM>. ) of the integrated toothless gear <NUM> meshes with the driving rack tooth part 461c of the one second rack bar 461a, the first cam receiving part 472a of the cam member <NUM> is located on the + side in the Y direction with respect to the first protrusion <NUM>. At this time, note that the tooth part 49a of the integrated toothless gear <NUM> does not mesh with the first rack tooth part 451a of the first rack bar <NUM>.

In this state, the first cam receiving part 472a and the first protrusion <NUM> face each other with a slight gap in the Y direction interposed therebetween (see <FIG>). As a result, even when an external force on the + side in the Y direction (force in the direction of the arrow Fa in <FIG>) is applied to the first rack bar <NUM>, the movement of the first rack bar <NUM> toward the + side in the Y direction is prevented.

Specifically, when the external force Fa on the + side in the Y direction is applied to the first rack bar <NUM>, the first rack bar <NUM> moves to the + side in the Y direction from the position indicated by the two-dot chain line in <FIG> to the position indicated by the solid line. In this state, the first protrusion <NUM> abuts on the first cam receiving part 472a to prevent the first rack bar <NUM> from moving toward the + side in the Y direction.

Note that in the state shown in <FIG>, the outer peripheral surface of the cam member <NUM> and the first protrusion <NUM> face each other with a slight gap in the Y direction interposed therebetween. As a result, even when the external force on the + side in the Y direction is applied to the first rack bar <NUM>, the movement of the first rack bar <NUM> toward the + side in the Y direction is prevented.

On the other hand, as illustrated in <FIG>, in a state where the tooth part 49a of the integrated toothless gear <NUM> (the first tooth part 450a of the first toothless gear <NUM> in the cylinder connecting mechanism <NUM>) meshes with the first rack tooth part 451a of the first rack bar <NUM>, the second cam receiving part 472b of the cam member <NUM> is located on the + side in the Y direction with respect to the second protrusion <NUM>.

In this state (a state indicated by a two-dot chain line in <FIG>), the second cam receiving part 472b and the second protrusion <NUM> face each other with a slight gap in the Y direction interposed therebetween. As a result, even when the external force on the + side in the Y direction (arrow Fb in <FIG>) is applied to one of the second rack bars 461a, the one of the second rack bars 461a is prevented from moving toward the + side in the Y direction.

Specifically, when the external force Fb on the + side in the Y direction is applied to the one second rack bar 461a, the one second rack bar 461a moves from the position indicated by the two-dot chain line in <FIG> to the position indicated by the solid line in the + side in the Y direction. In this state, the second protrusion <NUM> abuts on the second cam receiving part 472b to prevent the one second rack bar 461a from moving toward the + side in the Y direction.

Hereinafter, the telescopic operation of the telescopic boom <NUM> and the operation of the actuator <NUM> at the time of the telescopic operation will be described with reference to <FIG> and <FIG>.

<FIG> is a timing chart at the time of the extension operation of the tip boom element <NUM> in the telescopic boom <NUM>.

The actuator <NUM> according to the present embodiment selectively realizes the pulling operation of the cylinder connecting pins 454a and 454b and the pulling operation of the boom connecting pin 144a by the switching of the rotation direction of one electric motor <NUM> and a switch gear (that is, the first toothless gear <NUM> and the second toothless gear <NUM>) that distributes the driving force of the electric motor <NUM> to the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM>.

Hereinafter, only the extension operation of the tip boom element <NUM> in the telescopic boom <NUM> will be described. Note that the retraction operation of the tip boom element <NUM> is reverse to the following procedure of the extension operation.

Note that in the following description, the state transition between the extended state and the retracted state of the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> is as described above. Therefore, a detailed description of the state transition of the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> will be omitted.

In addition, the control unit controls switching between ON and OFF of the electric motor <NUM> and switching between ON and OFF of the brake mechanism <NUM> based on the output of the position information detection device <NUM> described above.

<FIG> illustrates the retracted state of the telescopic boom <NUM>. In this state, the tip boom element <NUM> is connected to the intermediate boom element <NUM> via the boom connecting pin 144a. Thus, the tip boom element <NUM> cannot move in the longitudinal direction (left-right direction in <FIG>) relative to the intermediate boom element <NUM>.

In addition, in <FIG>, the tip portions of the cylinder connecting pins 454a and 454b are engaged with the pair of cylinder pin receiving parts 141a of the tip boom element <NUM>. That is, the tip boom element <NUM> and the cylinder member <NUM> are in a connected state.

In the state of <FIG>, the state of each member is as follows (see T0 to T1 in <FIG>).

Next, in the state illustrated in <FIG>, the electric motor <NUM> rotates forward (rotate in a first direction that is a clockwise direction as viewed from the tip side of the output shaft), and the boom connecting mechanism <NUM> of the actuator <NUM> moves the pair of boom connecting pins 144a in the direction of separating from the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM>. At this time, the boom connecting mechanism <NUM> transitions from the extended state to the retracted state.

The state of each member at the time of the state transition to <FIG> is as follows (see T1 to T2 in <FIG>).

With the above-described state transition, the engagement between the pair of boom connecting pins 144a and the pair of first boom pin receiving parts 142b of the intermediate boom element <NUM> is released (see <FIG>). Thereafter, the brake mechanism <NUM> is turned on, and the electric motor <NUM> is turned off.

Note that the timing to turn off the electric motor <NUM> and the timing to turn on the brake mechanism <NUM> are appropriately controlled by the control unit. For example, although not illustrated, the electric motor <NUM> is turned off after the brake mechanism <NUM> is turned on.

In the state of <FIG>, the state of each member is as follows (see T2 of <FIG>).

Next, in the state illustrated in <FIG>, pressure oil is supplied to a hydraulic chamber on the extension side in the telescopic cylinder <NUM> of the actuator <NUM>. Then, the cylinder member <NUM> moves in the extending direction (left side in <FIG>).

As the cylinder member <NUM> moves as described above, the tip boom element <NUM> moves in the extending direction (see <FIG>). At this time, the state of each unit is maintained until the state of T2 in <FIG> is T3.

Next, in the state illustrated in <FIG>, the brake mechanism <NUM> is released. Then, based on the urging force of the second urging mechanism <NUM>, the boom connecting mechanism <NUM> moves the pair of boom connecting pins 144a in a direction in which the pair of boom connecting pins 144a is engaged with the pair of second boom pin receiving parts 142c of the intermediate boom element <NUM>. At this time, the boom connecting mechanism <NUM> makes the state transition (that is, automatic return) from the retracted state to the extended state. That is, the insertion operation of the boom connecting mechanism <NUM> is performed.

The state of each member at the time of state transition to <FIG> is as follows (see T3 to T4 in <FIG>).

Then, as illustrated in <FIG>, the pair of boom connecting pins 144a is engaged with the pair of second boom pin receiving parts 142c of the intermediate boom element <NUM>.

The state of each member in the state illustrated in <FIG> is as follows.

Furthermore, in the state illustrated in <FIG>, the electric motor <NUM> is moved in the first direction (counterclockwise direction as viewed from the tip side of the output shaft), and the cylinder connecting mechanism <NUM> moves the pair of cylinder connecting pins 454a and 454b in the direction of separating from the pair of cylinder pin receiving parts 141a of the tip boom element <NUM>. At this time, the cylinder connecting mechanism <NUM> transitions from the extended state to the retracted state.

The state of each member at the time of state transition to <FIG> is as follows (see T4 to T5 in <FIG>).

Then, as illustrated in <FIG>, the tip portions of the pair of cylinder connecting pins 454a and 454b are disengaged from the pair of cylinder pin receiving parts 141a of the tip boom element <NUM>. Thereafter, the brake mechanism <NUM> is turned on, and the electric motor <NUM> is turned off.

The state of each member in the state illustrated in <FIG> is as follows (see T5 in <FIG>).

Thereafter, although not illustrated, when pressure oil is supplied to the hydraulic chamber on the retraction side in the telescopic cylinder <NUM> of the actuator <NUM>, the cylinder member <NUM> moves in the retracting direction (right side in <FIG>). At this time, since the tip boom element <NUM> and the cylinder member <NUM> are in the disconnected state, the cylinder member <NUM> moves alone in the retracting direction. When the intermediate boom element <NUM> is extended, the operations in <FIG> are performed on the intermediate boom element <NUM>.

In the mobile crane <NUM> of the present embodiment having the above configuration, it is possible to prevent the unintended pulling operation of the boom connecting mechanism <NUM> from occurring in the insertion operation of the cylinder connecting mechanism <NUM>. The reason is as described above.

In addition, in the mobile crane <NUM> of the present embodiment, it is also possible to prevent the unintended pulling operation of the cylinder connecting mechanism <NUM> from occurring in the insertion operation of the boom connecting mechanism <NUM>. The reason is also as described above.

Furthermore, in the case of the mobile crane <NUM> of the present embodiment, since the cylinder connecting mechanism <NUM> and the boom connecting mechanism <NUM> are an electric type, it is not necessary to provide a hydraulic circuit as in the conventional structure in the internal space of the telescopic boom <NUM>. Therefore, it is possible to improve the degree of freedom of design in the internal space of the telescopic boom <NUM> by effectively utilizing the space used by the hydraulic circuit.

In addition, in the present embodiment, the position information detection device <NUM> detects the positions of the cylinder connecting pins 454a and 454b and the boom connecting pins 144a and 144b. Therefore, in the present embodiment, the proximity sensor for position detection of the cylinder connecting pins 454a and 454b and the boom connecting pins 144a and 144b becomes unnecessary. Such a proximity sensor is provided, for example, at a position where an inserted state and a pulled state of each of the cylinder connecting pins 454a and 454b and the boom connecting pins 144a and 144b can be detected. In this case, at least the same number of proximity sensors as the number of cylinder connecting pins 454a, 454b and the number of second rack bars 461a, 461b are required. On the other hand, in the case of the present embodiment, the positions of each of the cylinder connecting pins 454a and 454b and the boom connecting pins 144a and 144b can be detected by the position information detection device <NUM> (that is, one detection unit) including one detection unit 44a as described above.

Claim 1:
A work machine (<NUM>), comprising:
a telescopic boom (<NUM>);
an actuator (<NUM>) that extends and retracts the telescopic boom (<NUM>);
a power source;
an electric drive source (<NUM>) that is provided in the actuator (<NUM>) and drives using power supplied from the power source;
an operating unit (<NUM>, <NUM>) that operates based on power of the electric drive source (<NUM>);
a first transmission shaft (<NUM>) that rotates on the basis of the power of the electric drive source (<NUM>);
a second transmission shaft (<NUM>) connected to the operating unit (<NUM>, <NUM>); and
a joint (<NUM>) that has a drive-side element (<NUM>) fixed to the first transmission shaft and a driven-side element (<NUM>) fixed to the second transmission shaft, the joint (<NUM>) being able to take a transmission state in which both the drive-side element (<NUM>) and the driven-side element (<NUM>) rotate and a non-transmission state in which only either the drive-side element (<NUM>) or the driven-side element (<NUM>) rotates,
the telescopic boom includes a first boom element (<NUM>, <NUM>) and a second boom element (<NUM>, <NUM>) that are telescopically overlapped with each other, and characterized in that
the operating unit (<NUM>, <NUM>) includes:
a first connecting mechanism (<NUM>) that connects the first boom element (<NUM>, <NUM>) and the actuator (<NUM>) based on an urging force of a first urging mechanism (<NUM>) and releases the connection between the first boom element (<NUM>) and the actuator (<NUM>) based on the power of the electric drive source (<NUM>), and
a second connecting mechanism (<NUM>) that connects the first boom element (<NUM>) and the second boom element (<NUM>) based on an urging force of a second urging mechanism (<NUM>), and releases the connection between the first boom element (<NUM>, <NUM>) and the second boom element (<NUM>, <NUM>) on the basis of the power of the electric drive source (<NUM>).