JP2022187523A - Lower traveling body of mobile crane - Google Patents

Abstract

To provide a lower traveling body of a mobile crane that can reduce deflections that are caused in an axle when a suspended load is suspended in an upper turning body on the front side or the rear side of the lower traveling body.SOLUTION: In a lower traveling body 101, a right crawler frame 2R includes right load receiving parts 21R and 22R protruding to a left side from detachment sites 201 and 202 of a right frame main body 20R, and a left crawler frame 2L includes left load receiving parts 21L and 22L protruding to a right side from detachment sites 203 and 204 of a left frame main body 20L. The right load receiving part 21R and the left load receiving part 21L receive downward loads from intermediate parts M1 and M1 of right-front and left-front axle parts 11R and 11L and support the right-front axle part 11R and the left-front axle part 11L. The right load receiving part 22R and the left load receiving part 22L receive downward loads from intermediate parts M2 and M2 of right-rear and left-rear axle parts 12R and 12L and support the right-rear axle part 12R and the left-rear axle part 12L.SELECTED DRAWING: Figure 7

Description

The present invention relates to an undercarriage for mobile cranes.

For example, the mobile crane disclosed in Patent Document 1 includes an undercarriage that can travel on the ground and an upper rotating body mounted on the undercarriage. The upper rotating structure is equipped with working equipment including a boom and suspension ropes. The lower traveling body includes a car body that supports the upper revolving body so as to be able to turn around a turning center axis, front axles that extend to the right and left sides of the car body, and a right side of the car body behind the front axle. and a left and right rear axle, and a pair of left and right crawler frames that extend in the front-rear direction on the right and left sides of the turning center axis and support the front and rear axles.

JP 2018-70339 A JP 2017-171090 A

By the way, in a mobile crane, each axle bends downward due to the load transmitted from the upper revolving structure to the front and rear axles when a load is lifted. In particular, when the suspended load is suspended in the longitudinal direction with respect to the central axis of rotation, the load of the upper rotating body is applied to the front axle or the rear axle, compared to the case in which the suspended load is suspended in the lateral direction of the central axis of rotation. Since it tends to be biased toward the axle, the deflection tends to increase. If there is a difference in the amount of deflection depending on the orientation of the suspended load with respect to the central axis of rotation, the position of the suspended load will fluctuate, which may reduce the workability of the lifting operation. Specifically, when the front axle or the rear axle bends, the position of the base end of the boom (the position of the boom foot) is displaced, so the position of the tip of the boom is also displaced, causing the suspended load to swing. Therefore, it is desired to reduce the deflection of the front axle or the rear axle when a load is suspended on the upper revolving structure on the front side or the rear side of the undercarriage.

Patent document 2 discloses a technique of providing a pair of reinforcing members in the front and rear parts of the trunk of the car body in order to improve the rigidity of the front and rear parts of the car body. The pair of reinforcing members of the mobile crane of No. 1 do not restrain the deflection of the front and rear axles.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is capable of reducing the deflection of the axle when a load is suspended on the upper revolving structure on the front side or the rear side of the lower traveling structure. It is an object of the present invention to provide a crane undercarriage.

The undercarriage of the mobile crane of the present invention comprises: a car body that supports the upper revolving body of the mobile crane so as to be able to turn about a central axis of revolving; a front car body connecting portion connected to the car body; A front axle including a right front axle portion extending rightward from a front car body connection portion and a left front axle portion extending leftward from the front car body connection portion, and a rear side connected to the car body on the rear side of the front axle. a rear axle including a car body connecting portion, a right rear axle portion extending rightward from the rear car body connecting portion, and a left rear axle portion extending leftward from the rear car body connecting portion; a right crawler frame including a right frame main body extending in the longitudinal direction at the right frame main body having a right front axle support portion and a right rear axle support portion for supporting the right front axle portion and the right rear axle portion; a left crawler frame including a left frame body extending in the front-rear direction on the left side thereof, the left frame body having a left front axle support portion and a left rear axle support portion for supporting the left front axle portion and the left rear axle portion; wherein the right front axle portion has a supported portion supported by the right front axle support portion and an intermediate portion between the supported portion and the front car body connecting portion, and the right rear axle The portion has a supported portion supported by the right rear axle support portion and an intermediate portion between the supported portion and the rear car body connecting portion, and the left front axle portion includes the left front axle support portion. A supported portion supported by the axle support portion and an intermediate portion between the supported portion and the front car body connection portion are provided, and the left rear axle portion is supported by the left rear axle support portion. and an intermediate portion between the supported portion and the rear car body connection portion, and the right crawler frame includes the right front axle support portion and the right rear axle support portion of the right frame main body. At least one right load receiving portion having a shape protruding leftward from at least one deviating portion that is deviated from the axle support portion in the front-rear direction, the at least one right load receiving portion It is possible to receive a downward load from the intermediate portion of the right front axle portion to support the right front axle portion, and to receive a downward load from the intermediate portion of the right rear axle portion to support the right rear axle portion. and the left crawler frame is mounted on the left front axle of the left frame main body. At least one left load receiving portion having a shape protruding rightward from at least one deviating portion that is deviated in the longitudinal direction with respect to the support portion and the left rear axle support portion; The load receiving portion receives a downward load from the intermediate portion of the left front axle portion to support the left front axle portion, and receives a downward load from the intermediate portion of the left rear axle portion to support the left rear axle portion. is configured to be able to support

In the undercarriage of this mobile crane, the right load receiving portion receives a downward load from the intermediate portion of the right front axle portion to support the right front axle portion, and the left load receiving portion receives a downward load from the intermediate portion of the left front axle portion. Since the left front axle portion is supported by receiving the load, it is possible to reduce deflection of the front axle when a load is suspended on the upper revolving structure on the front side of the lower traveling structure. Similarly, in this undercarriage, the right load receiving portion receives a downward load from the intermediate portion of the right rear axle portion to support the right rear axle portion, and the left load receiving portion receives a downward load from the intermediate portion of the left rear axle portion. Since the left rear axle part is supported by receiving a downward load, it is possible to reduce deflection of the rear axle when a load is hung on the upper revolving body on the rear side of the lower traveling body. Further, in this undercarriage, the at least one right load bearing portion is located on the left side of at least one detached portion, which is a portion of the right frame main body deviated in the front-rear direction from the right front axle support portion and the right rear axle support portion. It has a shape that protrudes into the By providing at least one such right load receiving portion, the right front axle portion and the right rear axle portion are supported and both vertical loads (downward loads) from the right front axle portion and the right rear axle portion are received. becomes possible. Similarly, in this undercarriage, the at least one left load bearing portion is separated from at least one detached portion, which is a portion deviated in the longitudinal direction from the left front axle support portion and the left rear axle support portion of the left frame body. It has a shape that protrudes to the right. By providing such at least one left load bearing portion, the left front axle portion and the left rear axle portion are supported, and both of the vertical loads (downward loads) from the left front axle portion and the left rear axle portion are received. becomes possible.

In the undercarriage, as described above, the at least one right load receiving portion may have a shape projecting leftward from the at least one detached portion of the right frame main body. The load receiving portion may have a shape protruding rightward from the at least one detached portion of the left frame main body. However, when a load is suspended from the upper rotating structure on the front side of the lower traveling structure, the load transmitted from the upper rotating structure to the front axle via the car body includes not only the downward load component but also the load on the front axle. It also includes a torsional load component on the front axle that deflects the top surface forward. In addition, when a load is suspended on the upper revolving structure on the rear side of the lower traveling structure, the load transmitted from the upper revolving structure to the rear axle via the car body includes not only the downward load component but also the rear axle load. It also includes a torsional load component on the rear axle that causes the upper surface of the torsion to deflect rearward. Therefore, each of the right load receiving portion and the left load receiving portion supports the front axle at a position corresponding to the front side portion of the front axle, and supports the rear axle at a position corresponding to the rear side portion of the rear axle. It is preferable to have a structure in which the support cross-section is enlarged by .

That is, the at least one detached portion where the at least one right load bearing portion is connected to the right frame main body includes a right front portion, which is a portion of the right frame main body on the front side of the right front axle support portion, and the right frame. a right rear portion that is a portion of the main body that is on the rear side of the right rear axle support portion, and the at least one right load receiving portion has a shape that protrudes leftward from the right front portion. and a right rear load bearing portion having a shape protruding leftward from the right rear portion, the right front load bearing portion receiving a downward load component from the middle portion of the right front axle portion to move the right front axle. the right rear load bearing portion is configured to receive a downward load component from the intermediate portion of the right rear axle portion to support the right rear axle portion; The at least one detached portion where the two left load bearing portions are connected to the left frame main body is a left front portion, which is a portion of the left frame main body on the front side of the left front axle support portion, and the left front portion of the left frame main body. a left rear portion that is a portion rearward of the rear axle support portion, wherein the at least one left load bearing portion includes a left front load bearing portion having a shape protruding rightward from the left front portion; a left rear load bearing portion having a shape protruding rightward from the portion, wherein the left front load bearing portion receives a downward load component from the intermediate portion of the left front axle portion to support the left front axle portion. and the left rear load receiving portion is configured to support the left rear axle portion by receiving a downward load component from the intermediate portion of the left rear axle portion.

In this aspect, each of the right front load bearing portion and the left front load bearing portion can support the front axle, to which the downward load component and the torsional load component are transmitted, at a position corresponding to the front portion of the front axle. This allows the front right and left load receivers to more stably support the front axle. Similarly, each of the right rear load receiver and the left rear load receiver can support a rear axle to which downward load components and torsional load components are transmitted at positions corresponding to rearward portions of the rear axle. can. This allows the right and left rear load receptors to more stably support the rear axle.

Further, in this undercarriage, the right frame main body is configured to be able to change its position in the left-right direction with respect to the right front axle portion and the right rear axle portion, and the left frame main body is configured to be movable relative to the left front axle portion. And it may be configured such that the position in the left-right direction with respect to the left rear axle portion can be changed.

As described above, when the right front load bearing portion protrudes leftward from the right front portion of the right frame main body, and the right rear load bearing portion protrudes leftward from the right rear portion of the right frame main body, the right frame main body protrudes from the right front axle portion. Also, it is possible to easily realize a structure in which the right front load receiving portion and the right rear load receiving portion do not interfere with the car body when the position is changed in the left-right direction with respect to the right rear axle portion. Similarly, when the left front load bearing portion protrudes to the right from the left front portion of the left frame main body, and the left rear load bearing portion protrudes to the right from the left rear portion of the left frame main body, the left frame main body is positioned between the left front axle portion and the left front axle portion. It is possible to easily realize a structure in which the left front load receiving portion and the left rear load receiving portion do not interfere with the car body when the position is changed in the left-right direction with respect to the rear axle portion.

The undercarriage of the mobile crane is arranged to extend in the longitudinal direction between the right front load bearing portion and the intermediate portion of the right front axle portion in a plan view, and receives a downward load from the right front axle portion. to the right front load receiving portion, and between the right rear load receiving portion and the intermediate portion of the right rear axle portion in plan view in the longitudinal direction A right rear transmission section arranged to straddle the vehicle and configured to transmit the downward load received from the right rear axle section to the right rear load receiving section, and the left front load receiving section in a plan view. A left front that is disposed so as to straddle the front-rear direction between the left front axle and the intermediate portion, and is configured to be capable of transmitting a downward load received from the left front axle to the left front load receiving portion. A transmitting portion is disposed so as to straddle the front-rear direction between the left rear load receiving portion and the middle portion of the left rear axle portion in a plan view, and the downward load received from the left rear axle portion is transferred to the left rear axle portion. It is preferable to further include a left rear transmission portion configured to be able to transmit to the rear load receiving portion.

In this aspect, the right front load bearing portion is directed downward from the middle portion of the right front axle portion via the right front transmission portion that is arranged to straddle the front right load bearing portion and the middle portion of the right front axle portion in the longitudinal direction. The right rear load bearing portion is arranged to span between the right rear load bearing portion and an intermediate portion of the right rear axle portion in the longitudinal direction. Through the right rear transmission section, the right rear axle section can be supported by receiving a downward load from the middle section of the right rear axle section. Similarly, the left front load bearing portion receives a downward load from the middle portion of the left front axle portion via the left front transmission portion that is disposed so as to straddle between the left front load bearing portion and the middle portion of the left front axle portion in the longitudinal direction. The left front axle portion can be supported by receiving a load, and the left rear load bearing portion is arranged to span between the left rear load bearing portion and an intermediate portion of the left rear axle portion in the longitudinal direction. Through the rear transmission section, the left rear axle section can be supported by receiving a downward load from the middle section of the left rear axle section.

In the undercarriage of the mobile crane, each of the right front load receiving portion and the left front load receiving portion has a load receiving surface facing upward, and the right front transmission portion is located at the intermediate portion of the right front axle portion. a front projecting portion projecting forward from the connecting intermediate portion; wherein the left front transmission portion includes a front projecting portion connected to the intermediate portion of the left front axle portion and projecting forward from the intermediate portion; The front projecting portion of the portion has a load transmission surface configured by a lower surface vertically opposed to the load receiving surface of the right front load receiving portion, and the front projecting portion of the left front transmission portion , and a load transmission surface constituted by a lower surface vertically opposed to the load receiving surface of the left front load receiving portion.

In this aspect, when a load is suspended on the upper revolving structure on the front side of the lower traveling structure, the front projecting portion of the right front transmission portion vertically absorbs the downward load received from the intermediate portion of the right front axle portion. The load can be transmitted to the right front load receiving portion via the load transmitting surface and the load receiving surface facing each other. The load can be transmitted to the front left load receiving portion via the load transmitting surface and the load receiving surface which are connected to each other.

In the undercarriage of the mobile crane, each of the right rear load receiving portion and the left rear load receiving portion has a load receiving surface facing upward, and the right rear transmission portion is mounted on the right rear axle portion. A rear overhanging portion connected to the intermediate portion and projecting rearward from the intermediate portion, wherein the left rear transmission portion is connected to the intermediate portion of the left rear axle portion and projects rearward from the intermediate portion. The rear projecting portion of the right rear transmission portion has a load transmission surface configured by a lower surface vertically opposed to the load receiving surface of the right rear load receiving portion. Preferably, the rear projection of the left rear transmission portion has a load transmission surface formed by a lower surface vertically opposed to the load reception surface of the left rear load reception portion.

In this aspect, when a load is suspended on the upper revolving body on the rear side of the undercarriage, the rear overhanging portion of the right rear transmission portion receives a downward load from the intermediate portion of the right rear axle portion. , the load can be transmitted to the right rear load receiving portion via the load transmitting surface and the load receiving surface that face each other in the vertical direction. can be transmitted to the left rear load receiving portion via the vertically opposed load transmitting surface and load receiving surface.

In the undercarriage of the mobile crane, each of the intermediate portion of the right front axle portion and the intermediate portion of the left front axle portion has an axle lower surface facing downward, and the right front transmission portion receives the right front load. A rear side projecting portion connected to the receiving portion and projecting rearward from the right front load receiving portion, wherein the left front transmission portion is connected to the left front load receiving portion and projecting rearward from the left front load receiving portion. the rear projecting portion of the right front transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the right front axle portion; The rear side projecting portion of the left front transmission portion may have a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the left front axle portion.

In this aspect, when a load is suspended on the upper revolving body on the front side of the lower traveling body, the rear side projecting portion of the right front transmission portion shifts the downward load component received from the intermediate portion of the right front axle portion up and down. can be transmitted to the right front load receiving portion via the axle lower surface and the load transmission surface facing each other in the direction, and the rear side projecting portion of the left front transmission portion receives the downward load component from the intermediate portion of the left front axle portion, The load can be transmitted to the left front load receiving portion via the axle lower surface and the load transmission surface that face each other in the vertical direction.

In the undercarriage of the mobile crane, each of the intermediate portion of the right rear axle portion and the intermediate portion of the left rear axle portion has an axle lower surface facing downward, and the right rear transmission portion comprises: A front overhang portion connected to the right rear load receiving portion and projecting forward from the right rear load receiving portion is included, and the left rear transmission portion is connected to the left rear load receiving portion and extends forward from the left rear load receiving portion. The load transmission device includes a projecting front side projecting portion, and the front projecting portion of the right rear transmission portion is constituted by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the right rear axle portion. The front protruding portion of the left rear transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the left rear axle portion. may be

In this aspect, when a load is suspended on the upper revolving structure behind the lower traveling structure, the front projecting portion of the right rear transmission portion absorbs the downward load component received from the intermediate portion of the right rear axle portion. , the load can be transmitted to the right rear load receiving portion via the lower surface of the axle and the load transmitting surface that face each other in the vertical direction, and the front projecting portion of the left rear transmitting portion receives the downward load from the intermediate portion of the left rear axle portion. A load component can be transmitted to the left rear load receiver via the axle lower surface and the load transmission surface, which face each other in the vertical direction.

In the undercarriage of the mobile crane, the right front transmission section includes at least one connecting pin extending in the longitudinal direction between the right front load bearing section and the intermediate portion of the right front axle section to connect them. The left front transmission section may include at least one connecting pin extending in the longitudinal direction between the left front load bearing section and the intermediate portion of the left front axle section to connect them.

In this aspect, when a load is suspended on the upper revolving body on the front side of the lower traveling body, the connecting pin of the right front transmission section transfers the downward load component received from the intermediate portion of the right front axle section to the right front load receiving section. The connecting pin of the left front transmission portion can transmit the downward load component received from the intermediate portion of the left front axle portion to the left front load receiving portion.

In the undercarriage of the mobile crane, the right rear transmission part extends in the longitudinal direction between the right rear load receiving part and the middle part of the right rear axle part to connect them. The left rear transmission portion includes at least one connection pin extending in the longitudinal direction between the left rear load receiving portion and the intermediate portion of the left rear axle portion to connect them. You can

In this aspect, when a load is suspended on the upper revolving body behind the lower traveling body, the connecting pin of the right rear transmission section transfers the downward load component received from the intermediate portion of the right rear axle section to the right rear axle. The connecting pin of the left rear transmission portion can transmit the downward load component received from the intermediate portion of the left rear axle portion to the left rear load reception portion.

In the mobile crane undercarriage, the front axle has a front side surface facing forward, the rear axle has a rear side surface facing rearward, and the right front load bearing portion comprises the right front axle portion. and a load received from the intermediate portion of the right front axle portion when a load is suspended on the upper revolving body on the front side of the lower traveling body. can be transmitted from the right front facing portion to the right front portion of the right frame main body, and the left front load bearing portion is configured to be transmitted to the intermediate portion of the left front axle portion in the longitudinal direction. and at least a part of the load received from the intermediate portion of the left front axle portion when a load is suspended on the upper rotating body on the front side of the lower traveling body is provided by the left front The right rear load bearing portion is configured to be able to transmit the load from the facing portion to the left front portion of the left frame main body, and the right rear load bearing portion faces the middle portion of the right rear axle portion in the longitudinal direction. at least a part of the load received from the intermediate portion of the right rear axle portion when a load is suspended on the upper rotating body behind the lower traveling body is absorbed by the right rear facing portion to the right rear portion of the right frame main body, and the left rear load bearing portion is configured to face the intermediate portion of the left rear axle portion in the front-rear direction. at least a part of the load received from the intermediate portion of the left rear axle portion when a load is suspended on the upper rotating body on the rear side of the lower traveling body from the left rear facing portion It is preferable to be configured so that it can be transmitted to the left rear portion of the left frame main body.

In this aspect, the right front load receiving portion and the left front load receiving portion transfer at least part of the load received from the intermediate portion of the right front axle portion and the intermediate portion of the left front axle portion to the right front portion of the right frame main body from the right front facing portion and the left front facing portion. and the left front portion of the left frame main body, respectively. At least a part of it can be transmitted from the right rear facing portion and the left rear facing portion to the right rear portion of the right frame main body and the left rear portion of the left frame main body, respectively. Therefore, in this undercarriage, in each of the right crawler frame and the left crawler frame, the distance in the front-rear direction between the front end portion and the portion to which the load is transmitted can be made smaller than in the conventional art. The distance in the front-rear direction between the portion and the portion to which the load is transmitted can be made smaller than in the prior art. This makes it possible to reduce the deflection that occurs in the front part of each crawler frame due to the loads transmitted via the front axle, and to the front parts due to the loads transmitted via the rear axle. To make it possible to reduce deflection occurring in the rear part of a crawler frame.

According to the present invention, there is provided an undercarriage for a mobile crane that is capable of reducing the deflection that occurs in the axle when a load is suspended on the upper revolving body on the front side or the rear side of the undercarriage. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows an example of a mobile crane provided with the undercarriage which concerns on embodiment. It is a perspective view which shows the undercarriage which concerns on embodiment. It is a top view which shows the undercarriage which concerns on embodiment. It is a top view which shows the undercarriage which concerns on embodiment. FIG. 4 is an enlarged perspective view of the undercarriage shown in FIG. 3 as viewed from the direction of arrow V; FIG. 4 is a front view of the undercarriage shown in FIG. 3 as viewed from the direction of arrow VI; It is a left view which shows the right crawler frame of the undercarriage which concerns on embodiment. It is an expansion perspective view which shows the undercarriage based on the modification 1 of embodiment. It is a front view which shows the undercarriage which concerns on the modification 1 of embodiment. It is a left view which shows the right crawler frame of the undercarriage which concerns on the modification 1 of embodiment. It is an expansion perspective view which shows the undercarriage based on the modification 2 of embodiment. It is a front view which shows the undercarriage which concerns on the modification 2 of embodiment. It is a left view which shows the right crawler frame of the undercarriage which concerns on the modified example 2 of embodiment. It is a front view which shows the undercarriage which concerns on the modified example 3 of embodiment. It is a front view which shows the undercarriage which concerns on the modification 4 of embodiment. It is a left view which shows the right crawler frame of the undercarriage which concerns on the modification 5 of embodiment.

Hereinafter, the undercarriage of the mobile crane according to the embodiment will be described with reference to the drawings. In the drawings, the letters "front", "rear", "right", "left", "upper" and "lower" are written, but these are based on the direction in which the lower traveling body advances and retreats. and That is, the front-rear direction of the undercarriage is a horizontal direction in which a crawler frame, which will be described later, extends, and the left-right direction of the undercarriage is a horizontal direction orthogonal to the front-rear direction. The vertical direction of the lower traveling body is a direction parallel to the central axis of revolving of the upper revolving body.

[Overall structure of mobile crane]
As shown in FIG. 1 , a mobile crane 100 according to this embodiment includes a lower traveling body 101 and an upper rotating body 102 . The lower traveling body 101 is configured to support the upper revolving body 102 from below so as to be able to revolve and to travel on the ground.

The upper revolving body 102 is arranged on the lower running body 101 . The upper swing body 102 includes a swing frame 103 , a work device, a cab 104 and a counterweight 105 . The work implement, cab 104 and counterweight 105 are mounted on a swing frame 103 .

The work device is used for lifting a load (crane work) and the like. In this embodiment, the working device includes a boom 106, a lifting winch 107, a lifting rope 108, a hook device 109, a gantry 110, a hoisting winch 111, a lower spreader 112, a hoisting rope 113, It includes an upper spreader 114 and guy lines 115 . The working device is not limited to the specific example shown in FIG. 1, and may further include, for example, a jib (not shown) that can be attached to the tip of the boom.

The boom 106 is attached to the front part of the revolving frame 103 so as to be able to rise and fall, and a hook device 109 for hanging a load is suspended from the tip of the boom 106 via a suspension rope 108 . The hoisting winch 107 is mounted on the revolving frame 103 , and winds or unwinds the hoisting rope 108 to hoist or hoist the hook device 109 . The gantry 110 is erected on the rear portion of the swing frame 103 . The guy line 115 has one end connected to the tip of the boom 106 and the other end connected to the upper spreader 114 . A lower spreader 112 is provided at the upper end of the gantry 110, and the lower spreader 112 and the upper spreader 114 are spaced apart from each other. A hoisting rope 113 is wound around the lower spreader 112 and the upper spreader 114 . The hoisting winch 111 is mounted on the revolving frame 103 , and by winding or unreeling the hoisting rope 113 , the distance between the upper spreader 114 and the lower spreader 112 is reduced or increased. As the distance between the spreaders 112 and 114 is reduced or expanded, the boom 106 is raised and lowered.

[Structure of Undercarriage]
FIG. 2 is a perspective view showing the undercarriage 101 according to the embodiment, and FIG. 3 is a plan view thereof. In this embodiment, as shown in FIGS. 1, 2 and 3, the longitudinal direction of the lower traveling body 101 is the longitudinal direction of the crawler frames 2R and 2L, which will be described later. The direction is from the wheel 24R (drive tumbler) of the crawler frame to the wheel 23R (idler), and the rear is the opposite direction. However, the front-rear direction of the lower running body 101 may be defined as the direction opposite to the direction defined in FIGS. 2 and 3 .

The lower traveling body 101 includes a lower frame 1, a right traveling device, and a left traveling device. The lower frame 1 is a frame for supporting the upper revolving body 102 so that it can revolve. Each of the right and left running devices is a device for running on the ground while supporting the lower frame 1 .

The lower frame 1 includes a car body 10, a front axle 11, a rear axle 12, and a pair of crawler moving cylinders 15R and 15L. The car body 10, the front axle 11 and the rear axle 12 form an integral structure. 3, the illustration of the pair of crawler moving cylinders 15R and 15L is omitted.

The car body 10 supports an upper revolving body 102 of the mobile crane 100 so as to be able to revolve around a revolving central axis C. As shown in FIG. The turning center axis C is substantially parallel to the vertical direction when the ground is horizontal. The carbody 10 includes a cylindrical portion 14 having a cylindrical shape centered on a turning center axis C, a turning bearing 13 supported on the upper portion of the cylindrical portion 14, and a lower portion of the cylindrical portion 14 supporting the cylindrical portion 14. a base portion 16; An upper revolving body 102 is rotatably mounted on the revolving bearing 13 .

The front axle 11 extends to the right and left from the car body 10 , and the rear axle 12 extends to the right and left from the car body 10 behind the front axle 11 . Specifically, in a plan view shown in FIG. 3 , the front axle 11 projects to the right and left from the front portion of the car body 10 , and the rear axle 12 projects to the right and left from the rear portion of the car body 10 . ing. In the present embodiment, each of the front axle 11 and the rear axle 12 has a columnar shape extending in parallel in the left-right direction, specifically a quadrangular columnar shape.

As shown in FIG. 2, the front axle 11 and the rear axle 12 are spaced apart in the longitudinal direction. The front axle 11 is located on the front side of the turning center axis C, and the rear axle 12 is located on the rear side of the turning center axis C. As shown in FIG. The base portion 16 is interposed between the front axle 11 and the rear axle 12 . The base portion 16 is connected to the front axle 11, the rear axle 12 and the tubular portion 14, so that the base portion 16, the front axle 11, the rear axle 12 and the tubular portion 14 form an integral structure. The base portion 16 is provided at the center of the front axle 11 and the rear axle 12 in the left-right direction. Therefore, in this embodiment, the structure has a substantially H shape in plan view shown in FIG.

Specifically, as shown in FIG. 3, the front axle 11 includes a front car body connecting portion C1 connected to the base portion 16 of the car body 10, and a right front axle portion 11R extending rightward from the front car body connecting portion C1. , and a left front axle portion 11L extending leftward from the front car body connection portion C1. The rear axle 12 includes a rear car body connection portion C2 connected to the base portion 16 of the car body 10 on the rear side of the front axle 11, and a right rear axle portion 12R extending rightward from the rear car body connection portion C2. , and a left rear axle portion 12L extending leftward from the rear car body connection portion C2.

The right travel device includes a right crawler frame 2R, a pair of wheels 23R and 24R, a right crawler belt 25R, a plurality of right rollers 26, and a travel drive device 29. Similarly, the left travel device includes a left crawler frame 2L, a pair of wheels 23L and 24L, a left crawler belt 25L, a plurality of left rollers 26, and a travel drive device 29. Each of the left and right crawler belts 25R and 25L is formed by connecting a plurality of shoes in a ring shape.

The right crawler frame 2R includes a right frame main body 20R, and the left crawler frame 2L includes a left frame main body 20L.

The right frame main body 20R has a shape extending in the front-rear direction on the right side of the turning center axis C. As shown in FIG. The right frame main body 20</b>R has a right front axle support portion 27 and a right rear axle support portion 28 . These axle support portions 27 and 28 are provided at positions corresponding to the front axle 11 and the rear axle 12, respectively, so that the right frame main body 20R can change its position in the left-right direction with respect to the front axle 11 and the rear axle 12. support the front axle 11 and the rear axle 12 respectively.

Each of the right front axle support portion 27 and the right rear axle support portion 28 has an inner surface defining a through-hole passing through the right frame main body 20R in the left-right direction, and each of the front axle 11 and the rear axle 12 has the through-hole. is inserted in the In this embodiment, the inner surface is four surfaces (front surface, rear surface, bottom surface and ceiling surface). The front and rear surfaces restrict longitudinal displacement of the corresponding axle, and the bottom and top surfaces restrict longitudinal displacement of the corresponding axle.

In the present embodiment, the right front axle support portion 27 includes a projecting piece 27a projecting leftward from the left side surface of the right frame body 20R positioned around the axle supporting portion 27, and a projecting piece 27a as a reinforcing portion. and a surrounding annular member 27b. The right rear axle support portion 28 further has a protruding piece 28a and an annular member 28b similar to those described above. By providing these members 27a, 27b, 28a, 28b, the right front axle support portion 27 and the right rear axle support portion 28 can support the front axle 11 and the rear axle 12 more stably.

Similarly, the left frame main body 20L has a shape extending in the front-rear direction on the left side of the turning center axis C. As shown in FIG. The left frame main body 20L has a left front axle support portion 27 and a left rear axle support portion 28 . These axle support portions 27 and 28 are provided at positions corresponding to the front axle 11 and the rear axle 12, respectively, so that the left frame main body 20L can change its position in the left-right direction with respect to the front axle 11 and the rear axle 12. support the front axle 11 and the rear axle 12 respectively. The specific structure of the axle support portions 27, 28 of the left frame main body 20L is the same as that of the axle support portions 27, 28 of the right frame main body 20R described above, so detailed description thereof will be omitted.

A pair of wheels 23R, 24R are rotatably supported by the front and rear ends of the right frame main body 20R. In this embodiment, the right front wheel 23R located on the front side is configured by an idler, and the right rear wheel 24R located on the rear side is configured by a drive tumbler. This drive tumbler is connected to a traveling drive device 29 supported by the rear end portion of the right frame main body 20R at a position adjacent to the drive tumbler. The travel drive device 29 includes, for example, a travel motor and a travel speed reducer.

The right crawler belt 25R has a belt-like structure that is looped around a pair of wheels 23R and 24R and is rotatable. In other words, the right crawler belt 25R is endlessly supported by the pair of wheels 23R and 24R. The right crawler belt 25R is constructed by connecting a large number of crawler shoes.

A plurality of protrusions are formed along the circumferential direction on the outer peripheral portion of the right rear wheel 24R, which is configured by the drive tumbler, so as to be engageable with the inner peripheral portion of the right crawler belt 25R. The right rear wheel 24R is provided with driving force from the traveling drive device 29, and this driving force is transmitted to the right crawler belt 25R. As a result, the right crawler belt 25R circulates. A right front wheel 23R constituted by an idler rotates following the right crawler belt 25R.

The plurality of right rollers 26 are rotatably supported under the right frame main body 20R of the right crawler frame 2R. The plurality of right rollers 26 are spaced in the front-rear direction between the pair of wheels 23R and 24R. The plurality of right rollers 26 press the right crawler belt 25R against the ground and guide the circular movement of the right crawler belt 25R.

Hereinafter, the right roller 26 (in the present embodiment, the right roller 26 closest to the wheel 23R) located at the forefront among the plurality of right rollers 26 is referred to as a right front end roller 261, and The rearward right roller 26 (in this embodiment, the right roller 26 closest to the wheel 24R) is referred to as the right trailing end roller 262 .

The structure of the pair of wheels 23L, 24L, the left crawler belt 25L, and the plurality of left rollers 26 in the left traveling device is the same as the structure of the pair of wheels 23R, 24R, the right crawler belt 25R, and the plurality of right rollers 26 in the above-described right traveling device. , are the same except that they are bilaterally symmetrical, so detailed description thereof will be omitted. In addition, hereinafter, the left roller 26 (in this embodiment, the left roller 26 closest to the wheel 23L) located at the forefront among the plurality of left rollers 26 is referred to as a left front end roller 261, and the plurality of left rollers 26 Among them, the rearmost left roller 26 (in this embodiment, the left roller 26 closest to the wheel 24L) is called a left rear end roller 262 .

A pair of crawler moving cylinders 15R and 15L of the lower frame 1 are hydraulic cylinders that are arranged between the front axle 11 and the rear axle 12 and connect the lower frame 1 with the right traveling device and the left traveling device. The tip of the right crawler moving cylinder 15R is fixed to the right crawler frame 2R of the right traveling device, and the tip of the left crawler moving cylinder 15L is fixed to the left crawler frame 2L of the left traveling device. Therefore, the right crawler frame 2R of the right traveling device is displaced in the horizontal direction according to the expansion and contraction of the right crawler moving cylinder 15R, and the left traveling device moves to the left according to the expansion and contraction of the left crawler moving cylinder 15L. The crawler frame 2L is displaced in the left-right direction. 3 shows a state in which the right crawler frame 2R and the left crawler frame 2L are farthest from the turning center axis C, and FIG. 4 shows a state in which the right crawler frame 2R and the left crawler frame 2L are closest to the turning center axis C. showing.

[Load transmission structure]
The load transmitted from the upper revolving body 102 to the front axle 11 via the carbody 10 when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101 includes a downward load component and a torsional load. Including ingredients. This torsional load component is a load component on the front axle that bends the upper surface of the front axle 11 forward. The load transmitted from the upper revolving body 102 to the rear axle 12 via the carbody 10 when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101 includes a downward load component and a torsional load component. load components. This torsional load component is a load component on the rear axle that causes the upper surface of the rear axle 12 to deflect rearward.

The lower traveling body 101 according to the present embodiment is provided with a load transmission structure described below, so that the downward load component (for example, the load component L in FIG. 6) transmitted from the upper rotating body 102 to the front axle 11 causes As a result, the deflection of the front axle 11 can be reduced, and the deflection of the rear axle 12 due to the downward load component transmitted from the upper rotating body 102 to the rear axle 12 can be reduced. In FIG. 6, the deflection that may occur in the front axle 11 is indicated by a chain double-dashed line.

Further, the lower traveling body 101 according to the present embodiment has a deflection caused in the right frame main body 20R and the left frame main body 20L due to the load transmitted from the upper revolving structure 102 to the front axle 11, specifically, the right front axle. The deflection occurring in the portion between the support portion 27 and the right front end roller 261 and the deflection occurring in the portion between the left front axle support portion 27 and the left front end roller 261 can be reduced. In addition, the lower traveling body 101 flexes in the right frame body 20R and the left frame body 20L due to the load transmitted from the upper revolving body 102 to the rear axle 12. The deflection occurring in the portion between the right rear end roller 262 and the deflection occurring in the portion between the left rear axle support portion 28 and the left rear end roller 262 can be reduced. The load transmission structure of the undercarriage 101 will be described in detail below.

First, a load transmission structure for reducing the deflection occurring in the front axle 11 and the rear axle 12 will be described.

As shown in FIG. 3, the right front axle portion 11R of the front axle 11 includes a supported portion S1 supported by the right front axle support portion 27 and an intermediate portion between the supported portion S1 and the front car body connecting portion C1. and M1. The right rear axle portion 12R of the rear axle 12 includes a supported portion S2 supported by the right rear axle support portion 28 and an intermediate portion M2 between the supported portion S2 and the rear car body connecting portion C2. have.

The left front axle portion 11L of the front axle 11 has a supported portion S1 supported by the left front axle support portion 27, and an intermediate portion M1 between the supported portion S1 and the front car body connecting portion C1. The left rear axle portion 12L of the rear axle 12 includes a supported portion S2 supported by the left rear axle support portion 28 and an intermediate portion M2 between the supported portion S2 and the rear car body connecting portion C2. have. 3, the range of the front car body connecting portion C1, the supported portions S1, S1, and the intermediate portions M1, M1 of the front axle 11, and the rear car body connecting portion C2, the supported portions S2, S2 of the rear axle 12 are shown. , and intermediate portions M2, M2 are indicated by arrows. Note that the supported portions S1 and S2 are arranged such that the distance between the right crawler frame 2R and the left crawler frame 2L in the left-right direction is increased when the lifting operation (crane operation) of the mobile crane 100 is performed, that is, as shown in FIG. These parts are supported by the front axle 11 and the rear axle 12 when expanded.

Each of the intermediate portion M1 of the right front axle portion 11R and the intermediate portion M1 of the left front axle portion 11L has a front side surface SF facing forward. As shown in FIGS. 2 and 3, each of the intermediate portion M2 of the right rear axle portion 12R and the intermediate portion M2 of the left rear axle portion 12L has a rear side surface SR facing rearward.

In this embodiment, each of the front side surface SF and the rear side surface SR is a plane parallel to the left-right direction and the up-down direction.

In the undercarriage 101 according to this embodiment, the right crawler frame 2R further includes a right front load receiving portion 21R and a right rear load receiving portion 22R, and the left crawler frame 2L includes a left front load receiving portion 21L and a left and a rear load bearing portion 22L. The right front load receiving portion 21R and the right rear load receiving portion 22R are examples of the right load receiving portion, and the left front load receiving portion 21L and the left rear load receiving portion 22L are examples of the left load receiving portion.

The lower running body 101 further includes a right front transmission section, a right rear transmission section, a left front transmission section, and a left rear transmission section.

In the present embodiment, the right front transmission portion includes a front overhang portion 41, the right rear transmission portion includes a rear overhang portion 42, the left front transmission portion includes a front overhang portion 43, and the The left rear transmission portion includes a rear overhang portion 44 . These projecting portions will be described later.

The right front load bearing portion 21R of the right crawler frame 2R has a shape that protrudes leftward from a right front portion 201, which is a portion of the right frame main body 20R that is on the front side of the right front axle support portion 27. As shown in FIG. The right front portion 201 is an example of a detached portion of the right frame main body 20R that is deviated in the front-rear direction from the right front axle support portion 27 and the right rear axle support portion 28 . Specifically, it is as follows.

As shown in FIGS. 5 and 7, each of the right front axle portion 11R and the left front axle portion 11L of the front axle 11 includes an upper plate portion 11A extending in the left-right direction and a space vertically apart from the upper plate portion 11A. A lower plate portion 11B which is arranged below the upper plate portion 11A with a space therebetween and extends in the left-right direction, and a front plate portion 11C which extends in the left-right direction so as to connect the upper plate portion 11A and the lower plate portion 11B on the front side thereof. , and a rear plate portion 11D extending in the left-right direction so as to connect the upper plate portion 11A and the lower plate portion 11B on the rear side thereof. Like the front axle 11, each of the right rear axle portion 12R and the left rear axle portion 12L of the rear axle 12 has a prism shape including an upper plate portion 12A, a lower plate portion 12B, a front plate portion 12C and a rear plate portion 12D. have a structure.

The right front load receiving portion 21R is arranged below the upper plate portion 21A projecting leftward from the right front portion 201 of the right frame main body 20R and the upper plate portion 21A with a gap in the vertical direction from the upper plate portion 21A. a lower plate portion 21B projecting leftward from the right front portion 201; It has a box-shaped structure including a rear plate portion 21D that projects leftward and connects the upper plate portion 21A and the lower plate portion 21B on the rear side thereof. The right rear load bearing portion 22R has a box-shaped structure similar to the right front load bearing portion 21R including an upper plate portion 22A, a lower plate portion 22B, a rear plate portion 22C, and a front plate portion 22D. The same applies to the structures of the left front load receiving portion 21L and the left rear load receiving portion 22L. Note that each of the load receiving portions 21R, 21L, 22R, and 22L is not limited to the box-shaped structure as described above, and may be configured by structural members such as H-shaped steel and I-shaped steel.

As shown in FIGS. 6 and 7, the right front load bearing portion 21R has a load bearing surface 21S facing upward at a portion corresponding to the intermediate portion M1 of the right front axle portion 11R. The load receiving surface 21S is formed by part of the surface of the right front load receiving portion 21R, and receives a downward load from the intermediate portion M1 of the right front axle portion 11R via the front overhang portion 41. As shown in FIG. In the present embodiment, the load receiving surface 21S is formed by a portion of the upper surface of the right front load receiving portion 21R on the rear side adjacent to the front axle 11, and faces the front overhang portion 41 in the vertical direction. Consists of

The left front load bearing portion 21L of the left crawler frame 2L has a shape protruding rightward from a left front portion 203, which is a portion of the left frame main body 20L on the front side of the left front axle support portion 27. As shown in FIG. The left front portion 203 is an example of a detached portion of the left frame main body 20L that is deviated in the front-rear direction from the left front axle support portion 27 and the left rear axle support portion 28 . The structure of the front left load receiving portion 21L has the same structure as that of the front right load receiving portion 21R except that the front right load receiving portion 21R faces in a different direction.

The left front load bearing portion 21L has a load bearing surface 21S facing upward at a portion corresponding to the intermediate portion M1 of the left front axle portion 11L. The load receiving surface 21S is formed of a portion of the surface of the left front load receiving portion 21L, and receives a downward load from the intermediate portion M1 of the left front axle portion 11L via the front overhang portion 43. As shown in FIG. In this embodiment, the load receiving surface 21S is formed by the rear portion of the upper surface of the left front load receiving portion 21L adjacent to the front axle 11, and the portion vertically facing the front projecting portion 43. Consists of

The front projecting portion 41 of the right front transmission portion is a structural member connected to the intermediate portion M1 of the right front axle portion 11R. Specifically, the front projecting portion 41 has a plate shape projecting forward from the upper portion of the front side surface SF of the right front axle portion 11R. As a result, the front projecting portion 41 is arranged to straddle the front-rear direction between the right front load bearing portion 21R and the middle portion M1 of the right front axle portion 11R in a plan view. The front projecting portion 41 has a plate shape extending in the left-right direction along the front side surface SF of the right front axle portion 11R. At least part of the lower surface of the front projecting portion 41 constitutes a load transmission surface 41S. The load transmitting surface 41S is positioned above the load receiving surface 21S of the right front load receiving portion 21R so as to vertically face the load receiving surface 21S.

The front projecting portion 43 of the left front transmission portion is a structural member connected to the left front axle portion 11L. Specifically, the front projecting portion 43 has a plate shape projecting forward from the upper portion of the front side surface SF of the left front axle portion 11L. As a result, the front projecting portion 43 is arranged so as to straddle the front-rear direction between the left front load bearing portion 21L and the middle portion M1 of the left front axle portion 11L in a plan view. The front projecting portion 43 has a plate shape extending in the left-right direction along the front side surface SF of the left front axle portion 11L. At least part of the lower surface of the front projecting portion 43 constitutes a load transmission surface 43S. The load transmitting surface 43S is positioned above the load receiving surface 21S of the left front load receiving portion 21L so as to vertically face the load receiving surface 21S.

In the lower traveling body 101, the front projecting portion 41 of the right front transmission portion transfers the downward load component received by the front projecting portion 41 from the right front axle portion 11R to the load transmission surface 41S and the load receiving surface 41S facing each other in the vertical direction. It is transmitted to the right front load bearing portion 21R via the surface 21S. Since the right front load bearing portion 21R is supported by the right frame main body 20R at the right front portion 201, it can receive this downward load component and support the right front axle portion 11R. The front projecting portion 43 of the left front transmission portion transmits a downward load component received by the front projecting portion 43 from the left front axle portion 11L through a load transmitting surface 43S and a load receiving surface 21S that face each other in the vertical direction. It is transmitted to the left front load receiving portion 21L. Since the left front load receiving portion 21L is supported by the left frame body 20L, it can receive this downward load component and support the left front axle portion 11L. Therefore, in the lower traveling body 101, it is possible to reduce the deflection of the right front axle portion 11R and the left front axle portion 11L when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101. .

Specifically, as shown in FIG. 3, the front car body connection portion C1 is connected to the car body 10, while the intermediate portion M1 of the right front axle portion 11R and the intermediate portion M1 of the left front axle portion 11L are , are provided at positions separated from the car body 10 in the left-right direction. Therefore, each of the intermediate portion M1 of the right front axle portion 11R and the intermediate portion M1 of the left front axle portion 11L is a portion that is more likely to bend than the front car body connection portion C1. Since the portion M1 is supported by the right front load receiving portion 21R and the left front load receiving portion 21L, respectively, the deflection occurring in the intermediate portion M1 can be reduced.

The right rear load bearing portion 22R of the right crawler frame 2R has a shape that protrudes leftward from a right rear portion 202, which is a portion behind the right rear axle support portion 28 of the right frame body 20R. The right rear portion 202 is an example of the detached portion of the right frame main body 20R. The structure of the right rear load receiving portion 22R has the same structure as that of the right front load receiving portion 21R except that the direction is different from that of the right front load receiving portion 21R.

The right rear load bearing portion 22R has a load bearing surface 22S facing upward at a portion corresponding to the intermediate portion M2 of the right rear axle portion 12R. The load receiving surface 22S is formed by part of the surface of the right rear load receiving portion 22R, and receives a downward load from the middle portion M2 of the right rear axle portion 12R via the rear overhang portion 42. As shown in FIG. In this embodiment, the load receiving surface 22S is formed by the front portion of the upper surface of the right rear load receiving portion 22R, which is adjacent to the rear axle 12, and faces the rear projecting portion 42 in the vertical direction. consists of parts.

The left rear load bearing portion 22L of the left crawler frame 2L has a shape protruding rightward from a left rear portion 204, which is a portion behind the left rear axle support portion 28 of the left frame main body 20L. The left rear portion 204 is an example of the detached portion of the left frame main body 20L. The structure of the left rear load receiving portion 22L has the same structure as the right front load receiving portion 21R except that the direction is different from that of the right front load receiving portion 21R.

The left rear load bearing portion 22L has a load bearing surface 22S facing upward at a portion corresponding to the intermediate portion M2 of the left rear axle portion 12L. The load receiving surface 22S is formed by part of the surface of the left rear load receiving portion 22L, and receives a downward load from the intermediate portion M2 of the left rear axle portion 12L via the rear overhang portion 44. As shown in FIG. In the present embodiment, the load receiving surface 22S is formed by the front portion of the upper surface of the left rear load receiving portion 22L adjacent to the rear axle 12, and faces the rear projecting portion 44 in the vertical direction. consists of parts.

The rear projecting portion 42 of the right rear transmission portion is a structural member connected to the intermediate portion M2 of the right rear axle portion 12R. Specifically, the rear overhanging portion 42 has a plate shape that overhangs rearward from the upper portion of the rear side surface SR of the right rear axle portion 12R. As a result, the rear protruding portion 42 is arranged to straddle the front-rear direction between the right rear load bearing portion 22R and the middle portion M2 of the right rear axle portion 12R in plan view. The rear overhang portion 42 has a plate shape extending in the left-right direction along the rear side surface SR of the right rear axle portion 12R. At least a portion of the lower surface of the rear protruding portion 42 constitutes a load transmission surface 42S. The load transmitting surface 42S is positioned above the load receiving surface 22S of the right rear load receiving portion 22R so as to vertically face the load receiving surface 22S.

The rear overhang portion 44 of the left rear transmission portion is a structural member connected to the intermediate portion M2 of the left rear axle portion 12L. Specifically, the rear overhanging portion 44 has a plate shape that overhangs rearward from the upper portion of the rear side surface SR of the left rear axle portion 12L. As a result, the rear protruding portion 44 is arranged so as to straddle in the front-rear direction between the left rear load bearing portion 22L and the intermediate portion M2 of the left rear axle portion 12L in a plan view. The rear overhanging portion 44 has a plate shape extending in the left-right direction along the rear side surface SR of the left rear axle portion 12L. At least a portion of the lower surface of the rear projection 44 constitutes a load transmission surface 44S. The load transmission surface 44S is positioned above the load receiving surface 22S of the left rear load receiving portion 22L so as to vertically face the load receiving surface 22S. Illustration of the load transmission surface 44S is omitted.

In the lower traveling body 101, the rear projecting portion 42 of the right rear transmission portion transfers the downward load component received by the rear projecting portion 42 from the right rear axle portion 12R to the load transmission surfaces facing in the vertical direction. 42S and the load receiving surface 22S to the right rear load receiving portion 22R. Since the right rear load bearing portion 22R is supported by the right frame main body 20R at the right rear portion 202, it can receive this downward load component and support the right rear axle portion 12R. Further, the rear projection 44 of the left rear transmission portion transfers the downward load component received by the rear projection 44 from the left rear axle portion 12L to a load transmission surface 44S and a load receiving surface facing each other in the vertical direction. 22S to the left rear load bearing portion 22L. Since the left rear load bearing portion 22L is supported by the left frame main body 20L, it can receive this downward load component and support the left rear axle portion 12L. Therefore, in the lower traveling body 101, when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, it is possible to reduce the deflection of the right rear axle portion 12R and the left rear axle portion 12L. be possible.

Next, a load transmission structure for reducing deflection occurring in the right frame main body 20R and the left frame main body 20L will be described. In the lower traveling body 101, the front axle 11 or the rear axle 12 undergoes torsional deformation with the front end roller 261 or the rear end roller 262 as a fulcrum, and as a result, bending deformation occurs in the right frame body 20R and the left frame body 20L. In order to suppress the occurrence of such torsional deformation and bending deformation, in the lower traveling body 101 according to the present embodiment, the right crawler frame 2R has bending rigidity due to the right front load receiving portion 21R and the right rear load receiving portion 22R. The bending rigidity of the left crawler frame 2L is improved by the left front load receiving portion 21L and the left rear load receiving portion 22L.

The right front load bearing portion 21R has a right front facing portion ST1 that faces the front side surface SF of the right front axle portion 11R in the longitudinal direction on the left side of the right front axle support portion 27 of the right frame body 20R. The right front load receiving portion 21R of the right crawler frame 2R receives a front load that the car body 10 receives from the upper revolving body 102 when a load is suspended from the upper revolving body 102 on the front side of the lower traveling body 101. It is configured so that it can be further transmitted from the right front facing portion ST1 to the right front portion 201 via the right front axle portion 11R. The front load that the right front load receiving portion 21R transmits from the right front facing portion ST1 to the right front portion 201 is the load that is applied to the upper revolving body 102 when the load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101. part of the total load received from

The right rear load receiving portion 22R has a right rear facing portion ST2 that faces the rear side surface SR of the right rear axle portion 12R in the longitudinal direction on the left side of the right rear axle support portion 28 of the right frame body 20R. The right rear load receiving portion 22R of the right crawler frame 2R is a load that the car body 10 receives from the upper revolving body 102 when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101. It is configured such that the load can be further transmitted from the right rear facing portion ST2 to the right rear portion 202 via the right rear axle portion 12R. The rear load that the right rear load bearing portion 22R transmits from the right rear facing portion ST2 to the right rear portion 202 is applied to the car body 10 when a load is suspended on the upper revolving body 102 behind the lower traveling body 101. is a fraction of the total load received from the upper rotating body 102.

The left front load bearing portion 21L has a left front facing portion ST3 that faces the front side surface SF of the left front axle portion 11L in the longitudinal direction on the right side of the left front axle support portion 27 of the left frame body 20L. The left front load bearing portion 21L of the left crawler frame 2L is configured to be able to further transmit the front side load from the left front facing portion ST3 to the left front portion 203 via the left front axle portion 11L. The front load that the left front load bearing portion 21L transmits from the left front facing portion ST3 to the left front portion 203 is such that when the load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the car body 10 is applied to the upper revolving body 102. part of the total load received from

The left rear load bearing portion 22L has a left rear facing portion ST4 that faces the rear side surface SR of the left rear axle portion 12L in the longitudinal direction on the right side of the left rear axle support portion 28 of the left frame body 20L. The left rear load receiving portion 22L of the left crawler frame 2L is configured to be able to further transmit the rear load from the left rear facing portion ST4 to the left rear portion 204 via the left rear axle portion 12L. be. The rear load that the left rear load receiving portion 22L transmits from the left rear facing portion ST4 to the left rear portion 204 is applied to the car body 10 when a load is suspended on the upper revolving body 102 behind the lower traveling body 101. is a fraction of the total load received from the upper rotating body 102.

In the lower traveling body 101 according to the present embodiment having the load transmission structure as described above, the right front load receiving portion 21R of the right crawler frame 2R and the left front load receiving portion 21L of the left crawler frame 2L are configured such that the car body 10 is the upper revolving body. The front load received from 102 can be transmitted from the right front facing portion ST1 and the left front facing portion ST3 to the right front axle support portion 27 and the left front portion 203 on the front side of the left front axle support portion 27, respectively. . Specifically, when the carbody 10 receives the front load from the upper revolving body 102 when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the front load is applied to the right front axle portion 11R. and the left front axle portion 11L, respectively, from the front side surface SF of the right front axle portion 11R and the front side surface SF of the left front axle portion 11L to the right front facing portion ST1 of the right front load receiving portion 21R and the left front facing portion of the left front load receiving portion 21L. Each is transmitted to ST3. The right front load receiving portion 21R is a member that continues from the right front facing portion ST1 to the right front portion 201, and the left front load receiving portion 21L is a member that continues from the left front facing portion ST3 to the left front portion 203. The portion 21R and the left front load receiving portion 21L can transmit the front load transmitted to the right front facing portion ST1 and the left front facing portion ST3, respectively, to the right front portion 201 and the left front portion 203, respectively.

Similarly, the right rear load receiving portion 22R of the right crawler frame 2R and the left rear load receiving portion 22L of the left crawler frame 2L receive the rear load that the car body 10 receives from the upper revolving body 102 by the right rear facing portion ST2 and the left rear load receiving portion 22L. It is possible to transmit from the left rear facing portion ST4 to the right rear portion 202 and the left rear portion 204 on the rear side of the right rear axle support portion 28 and the left rear axle support portion 28, respectively. Specifically, when the car body 10 receives the rear load from the upper revolving body 102 when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, the rear load is applied to the right side. are transmitted to the rear axle portion 12R and the left rear axle portion 12L, respectively, from the rear side surface SR of the right rear axle portion 12R and the rear side surface SR of the left rear axle portion 12L to the right rear facing portion ST2 of the right rear load receiving portion 22R and the They are respectively transmitted to the left rear facing portion ST4 of the left rear load receiving portion 22L. The right rear load bearing portion 22R is a member that continues from the right rear facing portion ST2 to the right rear portion 202, and the left rear load bearing portion 22L is a member that continues from the left rear facing portion ST4 to the left rear portion 204. , the right rear load receiving portion 22R and the left rear load receiving portion 22L transfer the rear loads transmitted to the right rear facing portion ST2 and the left rear facing portion ST4, respectively, to the right rear portion 202 and the left rear portion 204. Each can be transmitted.

On the other hand, in a conventional lower traveling body that does not have a load receiving portion as described above, the front load that the car body receives from the upper revolving structure is transmitted from the front axle to the right front axle support portion of the right crawler frame and the left front of the left crawler frame. It is transmitted to the axle supports and not forwardly beyond these axle supports. Similarly, the rear load received by the carbody from the upper rotating body is transmitted from the rear axle to the right rear axle support portion of the right crawler frame and the left rear axle support portion of the left crawler frame. It is not transmitted to the rear side.

Therefore, in the undercarriage 101 according to the present embodiment, the load is transmitted to the portion corresponding to the tipping fulcrum on the front side in each of the right frame main body 20R of the right crawler frame 2R and the left frame main body 20L of the left crawler frame 2L. The distance in the longitudinal direction between the part corresponding to the tipping fulcrum on the rear side and the part to which the load is transmitted can be made smaller than in the conventional undercarriage. can be made smaller than the undercarriage of the This is due to the deflection that occurs in the front portions of the right frame body 20R and the left frame body 20L due to the load transmitted from the upper revolving body 102 to the front axle 11, and the deflection that is transmitted from the upper revolving body 102 to the rear axle 12. It is possible to reduce the bending caused in the rear parts of the right frame main body 20R and the left frame main body 20L due to the load as compared with the conventional art.

Here, in the mobile crane 100 provided with the lower traveling body 101 as shown in FIGS. The end has an arc shape in side view. Therefore, the front and rear ends of the crawler belts 25R and 25L are lifted from the ground. In the right and left crawler belts 25R and 25L, when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the car body 10 receives the load from the upper revolving body 102, and the overturning fulcrum is formed. The portion that serves as the (front overturning fulcrum) is a portion corresponding to the right and left front end rollers 261 and 261, and is positioned behind the lower traveling structure 101 when a load is suspended on the upper revolving structure 102. The parts that become the overturning fulcrums (rear overturning fulcrums) when the body 10 receives the load from the upper revolving body 102 are the parts corresponding to the right and left rear end rollers 262 , 262 .

In the present embodiment, the right front load receiving portion 21R of the right crawler frame 2R is positioned so as to overlap the first straight line LA passing through the right front end roller 261 and the turning center axis C in plan view shown in FIG. is provided. The first straight line LA is a straight line that passes through the rotation center axis C and the central position of the right front end roller 261 in the width direction (horizontal direction) of the right front end roller 261 in plan view. The right front load receiving portion 21R provided at such a position can transmit the load to a portion closer to the portion of the right frame main body 20R corresponding to the front tipping fulcrum. This makes it possible to further reduce the deflection that occurs in the front portion of the right frame main body 20R due to the load.

Further, in the present embodiment, the right front portion 201 of the right frame main body 20R is provided at a position overlapping the first straight line LA in plan view shown in FIG. As a result, the right front load receiving portion 21R can directly transmit the load to a portion of the right frame main body 20R corresponding to the front tipping fulcrum. This makes it possible to further reduce the deflection that occurs in the front portion of the right frame main body 20R due to the load.

Note that the positional relationship between the right front load receiving portion 21R, the turning center axis C, and the right front end roller 261 as described above is obtained when these are viewed from above. The right front end roller 261 does not necessarily have the same position in the vertical direction, and may be arranged at positions shifted from each other in the vertical direction. The same applies to other load receiving portions 22R, 21L, 22L described below.

The right rear load bearing portion 22R of the right crawler frame 2R is provided at a position overlapping the second straight line LB passing through the right rear end roller 262 and the turning center axis C in plan view. The second straight line LB is a straight line passing through the rotation center axis C of the right rear end roller 262 and the central position in the width direction (horizontal direction) of the right rear end roller 262 in plan view. be. Also, the right rear portion 202 of the right frame main body 20R is provided at a position overlapping the second straight line LB in plan view. The effects obtained by these configurations are as described above.

The left front load bearing portion 21L of the left crawler frame 2L is provided at a position overlapping a third straight line LC passing through the left front end roller 261 and the turning center axis C in plan view. The third straight line LC is a straight line that passes through the rotation center axis C and the central position of the left front end roller 261 in the width direction (horizontal direction) on the rotation center axis of the left front end roller 261 in a plan view. Further, the left front portion 203 of the left frame main body 20L is provided at a position overlapping the third straight line LC in plan view. The effects obtained by these configurations are as described above.

The left rear load receiving portion 22L of the left crawler frame 2L is provided at a position overlapping the fourth straight line LD passing through the left rear end roller 262 and the turning center axis C in plan view. The fourth straight line LD is a straight line that passes through the rotation center axis C of the left rear end roller 262 and the central position in the width direction (horizontal direction) of the left rear end roller 262 in a plan view. be. Also, the left rear portion 204 of the left frame main body 20L is provided at a position overlapping the fourth straight line LD in plan view. The effects obtained by these configurations are as described above.

In this embodiment, as shown in FIG. 3, the right front portion 201 of the right frame main body 20R is positioned such that the front-rear position of the right front portion 201 and the front-rear position of the right front end roller 261 overlap each other. is provided. Specifically, the front end F1 of the right front portion 201 is located forward of the front end of the right front end roller 261, and the rear end R1 of the right front portion 201 is located rearward of the rear end of the right front end roller 261. there is As a result, the right front load receiving portion 21R can directly transmit the load to a portion of the right frame main body 20R corresponding to the front tipping fulcrum.

Similarly, the right rear portion 202 of the right frame main body 20R is provided at a position where the front-rear position of the right rear portion 202 and the front-rear position of the right rear end roller 262 overlap. Specifically, the rear end R2 of the right rear portion 202 is positioned rearward of the rear end of the right rear end roller 262, and the front end F2 of the right rear portion 202 is positioned forward of the front end of the right rear end roller 262. located in The same applies to the longitudinal positional relationship between the left front portion 203 and the left front end roller 261 and the longitudinal positional relationship between the left rear portion 204 and the left rear end roller 262 .

Further, as shown in FIG. 3, the left ends of the right front load receiving portion 21R and the right rear load receiving portion 22R of the right crawler frame 2R are positioned to the left of the left end of the right crawler belt 25R. Then, the right front facing portion ST1 of the right front load receiving portion 21R receives the load from the front side surface SF of the front axle 11 at a position on the left side of the left end of the right crawler belt 25R, and faces the right rear of the right rear load receiving portion 22R. The portion ST2 is configured to receive the load from the rear side surface SR of the rear axle 12 at a position on the left side of the left end of the right crawler belt 25R. As a result, the load is efficiently transmitted from the right front facing portion ST1 and the left front facing portion ST3 to the right front portion 201 and the left front portion 203 through the portions near the first straight line LA and the third straight line LC.

Similarly, the right ends of the left front load receiving portion 21L and the left rear load receiving portion 22L of the left crawler frame 2L are positioned to the right of the right end of the left crawler belt 25L. The left front facing portion ST3 of the left front load receiving portion 21L receives the load from the front side surface SF of the front axle 11 at a position on the right side of the right end of the left crawler belt 25L, and faces the left rear of the left rear load receiving portion 22L. The portion ST4 is configured to receive the load from the rear side surface SR of the rear axle 12 at a position on the right side of the right end of the left crawler belt 25L. As a result, the load is efficiently transferred from the right rear facing portion ST2 and the left rear facing portion ST4 to the right rear portion 202 and the left rear portion 204 via the portions near the second straight line LB and the fourth straight line LD. transmitted.

Further, as shown in FIG. 3, the left ends of the right front load bearing portion 21R and the right rear load bearing portion 22R of the right crawler frame 2R are connected to the right front axle support portion 27 and the right rear axle support portion 28 of the right frame main body 20R. It is located to the left of the part between Similarly, the right end of each of the left front load bearing portion 21L and the left rear load bearing portion 22L of the left crawler frame 2L extends from the portion between the left front axle support portion 27 and the left rear axle support portion 28 of the left frame main body 20L. is also located on the right side.

In the present embodiment, as shown in FIG. 3, each of the front right load receiving portion 21R and the front left load receiving portion 21L has a shape such that its length in the left-right direction decreases toward the front in plan view. . Specifically, the front edge of the right front load bearing portion 21R has a shape extending obliquely rightward toward the right frame main body 20R, and the front edge of the left front load bearing portion 21L extends toward the left frame main body 20L. It has a shape that extends obliquely forward to the left. This can suppress an increase in the weight of each of the right front load receiving portion 21R and the left front load receiving portion 21L while ensuring the function of transmitting the front side load to the front side of each of the frame main bodies 20R and 20L as much as possible. Similarly, each of the right rear load bearing portion 22R and the left rear load bearing portion 22L has a shape such that its length in the left-right direction decreases toward the rear side in plan view. Specifically, the rear edge of the right rear load bearing portion 22R has a shape extending obliquely rearward to the right toward the right frame main body 20R, and the rear edge of the left rear load bearing portion 22L extends toward the left frame main body 20L. It has a shape that extends obliquely to the left and rearward. This increases the weight of each of the right rear load receiving portion 22R and the left rear load receiving portion 22L while ensuring the function of transmitting the rear load to the rear side of each of the frame main bodies 20R and 20L as much as possible. can be suppressed.

FIG. 8 is an enlarged perspective view showing the undercarriage 101 according to Modification 1 of the embodiment. FIG. 9 is a front view showing an undercarriage 101 according to Modification 1 of the embodiment. FIG. 10 is a left side view showing the right crawler frame 2R of the undercarriage 101 according to Modification 1 of the embodiment.

As shown in FIGS. 8 to 10, the lower traveling body 101 according to Modification 1 includes an overhanging portion 61 projecting forward from the lower portion of the front side surface SF of the right front axle portion 11R, and the front side surface SF of the left front axle portion 11L. a protruding portion 63 protruding forward from the lower portion of the right rear axle portion 12R, a protruding portion 62 protruding rearward from the lower portion of the rear side surface SR of the right rear axle portion 12R, and a rear side from the lower portion of the rear side surface SR of the left rear axle portion 12L. 5 to 7 in that it further includes a projecting portion 64 projecting outward, and other configurations are the same as those of the embodiment shown in FIGS.

The protruding portion 61 has a plate shape protruding forward from the lower portion of the front side surface SF of the right front axle portion 11R. The projecting portion 61 has a plate shape extending in the left-right direction along the front side surface SF of the right front axle portion 11R. At least part of the upper surface of the projecting portion 61 is positioned below the lower surface of the right front load bearing portion 21R so as to vertically face the lower surface of the right front load receiving portion 21R.

The protruding portion 63 has a plate shape protruding forward from the lower portion of the front side surface SF of the left front axle portion 11L. The projecting portion 63 has a plate shape extending in the left-right direction along the front side surface SF of the left front axle portion 11L. At least part of the upper surface of the overhanging portion 63 is positioned below the lower surface of the left front load receiving portion 21L so as to vertically face the lower surface of the left front load receiving portion 21L.

The protruding portion 62 has a plate shape protruding rearward from the lower portion of the rear side surface SR of the right rear axle portion 12R. The projecting portion 62 has a plate shape extending in the left-right direction along the rear side surface SR of the right rear axle portion 12R. At least part of the upper surface of the projecting portion 62 is positioned below the lower surface of the right rear load bearing portion 22R so as to vertically face the lower surface of the right rear load receiving portion 22R.

The protruding portion 64 has a plate shape protruding rearward from the lower portion of the rear side surface SR of the left rear axle portion 12L. The projecting portion 64 has a plate shape extending in the left-right direction along the rear side surface SR of the left rear axle portion 12L. At least part of the upper surface of the projecting portion 64 is positioned below the lower surface of the left rear load bearing portion 22L so as to vertically face the lower surface of the left rear load receiving portion 22L. 8 to 10, illustration of the projecting portion 64 is omitted.

In the lower traveling body 101 according to Modification 1, the projecting portions 61 to 64 support the right front load receiving portion 21R, the right rear load receiving portion 22R, the left front load receiving portion 21L, and the left rear load receiving portion 22L from below. be able to. This makes it possible to increase the rigidity of each load receiver and the axle support adjacent thereto.

FIG. 11 is an enlarged perspective view showing an undercarriage 101 according to Modification 2 of the embodiment. FIG. 12 is a front view showing an undercarriage 101 according to Modification 2 of the embodiment. FIG. 13 is a left side view showing the right crawler frame 2R of the undercarriage 101 according to Modification 2 of the embodiment.

As shown in FIGS. 11 to 13, the undercarriage 101 according to Modification 2 is different from the embodiment shown in FIGS. 5 to 7 in that it further includes a plurality of connecting pins P1 to P4. are similar to the previous embodiment shown in FIGS.

In Modification 2, the right front transmission portion includes a front projecting portion 41 and a connecting pin P1. The right rear transmission portion includes a rear protruding portion 42 and a connecting pin P2. The left front transmission portion includes a front projecting portion 43 and a connecting pin P3. The left rear transmission portion includes a rear side projecting portion 44 and a connecting pin P4. The structures of the front projecting portion 41, the rear projecting portion 42, the front projecting portion 43, and the rear projecting portion 44 are the same as those of the embodiment shown in FIGS.

As shown in FIGS. 11 to 13, an insertion hole H1 and an insertion hole H2 are provided in the right front load bearing portion 21R and the right front axle portion 11R, respectively. The connecting pin P1 is inserted through the insertion hole H1 and the insertion hole H2, and is arranged in a posture extending in the front-rear direction between the right front load receiving portion 21R and the right front axle portion 11R to connect them.

Similarly, the right rear load receiving portion 22R and the right rear axle portion 12R are provided with an insertion hole H1 and an insertion hole H2, respectively. The connecting pin P2 is inserted through the insertion hole H1 and the insertion hole H2, and is disposed between the right rear load bearing portion 22R and the right rear axle portion 12R so as to extend in the front-rear direction to connect them.

The left front load receiving portion 21L and the left front axle portion 11L are provided with an insertion hole H1 and an insertion hole H2, respectively. The connecting pin P3 is inserted through the insertion hole H1 and the insertion hole H2, and is disposed between the left front load receiving portion 21L and the left front axle portion 11L so as to extend in the front-rear direction to connect them.

The left rear load receiving portion 22L and the left rear axle portion 12L are provided with an insertion hole H1 and an insertion hole H2, respectively. The connecting pin P4 is inserted through the insertion hole H1 and the insertion hole H2, and is disposed between the left rear load bearing portion 22L and the left rear axle portion 12L so as to extend in the front-rear direction to connect them. 5 to 7, illustration of the connecting pin P4 is omitted.

In Modification 2, when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the connecting pins P1 and P3 receive downward load components from the right front axle portion 11R and the left front axle portion 11L. can be received at the connecting portions between the connecting pins P1 and P3 and the right front axle portion 11R and the left front axle portion 11L, and the received downward load component can be received by the connecting pins P1 and P3, the right front load receiving portion 21R and the left front load The load can be transmitted to the front right load receiving portion 21R and the front left load receiving portion 21L through the connection portion with the receiving portion 21L. The front right load receiving portion 21R and the front left load receiving portion 21L can receive the downward load component and support the front right axle portion 11R and the front left axle portion 11L, respectively.

That is, in this modification 2, when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the right front axle portion 11R is moved to the right front through the front overhang portion 41 and the connecting pin P1. The left front axle portion 11L is supported by the left front load receiving portion 21L via the front projecting portion 43 and the connecting pin P3. Therefore, in the undercarriage 101 according to Modification 2, it is possible to further reduce the bending occurring in the right front axle portion 11R and the left front axle portion 11L as compared with the embodiment shown in FIGS.

Similarly, in Modification 2, when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, the connecting pins P2 and P4 are connected to the right rear axle portion 12R and the left rear axle portion 12L. The downward load component received from the connecting pins P2 and P4 can be received at the connecting portions between the connecting pins P2 and P4 and the right rear axle portion 12R and the left rear axle portion 12L. The load can be transmitted to the right rear load receiving portion 22R and the left rear load receiving portion 22L through the connecting portions with the right rear load receiving portion 22R and the left rear load receiving portion 22L, respectively. The right rear load receiving portion 22R and the left rear load receiving portion 22L can receive the downward load component and support the right rear axle portion 12R and the left rear axle portion 12L, respectively.

That is, in Modification 2, when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, the right rear axle portion 12R pushes the rear overhanging portion 42 and the connecting pin P2. The left rear axle portion 12L is supported by the left rear load receiving portion 22L via the rear overhang portion 44 and the connecting pin P4. Therefore, in the undercarriage 101 according to Modification 2, it is possible to further reduce the deflection occurring in the right rear axle portion 12R and the left rear axle portion 12L as compared with the embodiment shown in FIGS.

FIG. 14 is a front view showing an undercarriage according to Modification 3 of the embodiment. FIG. 15 is a front view showing an undercarriage according to Modification 4 of the embodiment.

Each of these modifications 3 and 4 differs from modification 2 shown in FIGS. 11 to 13 in the number of connecting pins for connecting each load receiving portion and its corresponding axle portion. It is the same as the modification 2.

Specifically, in Modified Example 3 shown in FIG. 14, the right front load bearing portion 21R and the right front axle portion 11R are connected by a pair of connecting pins P1 spaced apart from each other in the vertical direction. Similarly, the left front load bearing portion 21L and the left front axle portion 11L are connected by a pair of connecting pins P3 spaced apart from each other in the vertical direction. Although not shown, the right rear load bearing portion 22R and the right rear axle portion 12R are connected by a pair of connecting pins P2 spaced apart from each other in the vertical direction. 22L and the left rear axle portion 12L are connected by a pair of connecting pins P4 which are spaced apart from each other in the vertical direction. Each connecting pin is arranged so as to extend in the front-rear direction.

In Modified Example 4 shown in FIG. 15, the right front load bearing portion 21R and the right front axle portion 11R are connected by a pair of connecting pins P1 spaced apart from each other in the left-right direction. Similarly, the left front load bearing portion 21L and the left front axle portion 11L are connected by a pair of connecting pins P3 spaced apart from each other in the left-right direction. Although not shown, the right rear load bearing portion 22R and the right rear axle portion 12R are connected by a pair of connecting pins P2 spaced apart from each other in the left-right direction. 22L and the left rear axle portion 12L are connected by a pair of connecting pins P4 spaced from each other in the left-right direction. Each connecting pin is arranged so as to extend in the front-rear direction.

In these modified examples 3 and 4, each load receiving portion and its corresponding axle are connected by a plurality of connecting pins, so that each load receiving portion and its corresponding axle are connected by one connecting pin. Compared to the case, the change in the relative position between each load receiving portion and the corresponding axle can be suppressed. That is, when each load receiving portion and its corresponding axle are connected by one connecting pin, each load receiving portion and its corresponding axle rotate relatively about the axis of the connecting pin. There is On the other hand, when each load receiving portion and its corresponding axle are connected by a plurality of connecting pins, the relative rotation as described above can be suppressed.

FIG. 16 is a left side view showing the right crawler frame of the undercarriage according to Modification 5 of the embodiment.

As shown in FIG. 16, the lower running body 101 according to Modification 5 is different from the embodiment shown in FIGS. , is similar to the previous embodiment shown in FIGS.

In Modification 5, the right front transmission portion includes a front projecting portion 41 and a rear projecting portion 51 . The right rear transmission portion includes a rear projecting portion 42 and a front projecting portion 52 . The left front transmission portion includes a front projecting portion 43 and a rear projecting portion 53 . The left rear transmission portion includes a rear projecting portion 44 and a front projecting portion 54 . The structures of the front projecting portion 41, the rear projecting portion 42, the front projecting portion 43, and the rear projecting portion 44 shown in FIG. 16 are the same as those of the embodiments shown in FIGS.

As shown in FIG. 16, the rear projecting portion 51 of the right front transmission portion is a structural member connected to the right front load receiving portion 21R. Specifically, the rear overhanging portion 51 has a plate shape that overhangs rearward from the lower portion of the rear side surface of the right front load receiving portion 21R. As a result, the rear protruding portion 51 is arranged so as to straddle in the front-rear direction between the right front load bearing portion 21R and the intermediate portion M1 of the right front axle portion 11R in a plan view. The rear side projecting portion 51 has a plate shape extending in the left-right direction along the right front axle portion 11R. At least a portion of the upper surface of the rear protruding portion 51 constitutes a load transmission surface 51S. The load transmission surface 51S is positioned below the axle lower surface 11S so as to vertically face the axle lower surface 11S forming part of the lower surface of the right front axle portion 11R.

The front projecting portion 52 of the right rear transmission portion is a structural member connected to the right rear load bearing portion 22R. Specifically, the front projecting portion 52 has a plate shape projecting forward from the lower portion of the front side surface of the right rear load receiving portion 22R. As a result, the front projecting portion 52 is arranged to straddle the front-rear direction between the right rear load bearing portion 22R and the middle portion M2 of the right rear axle portion 12R in plan view. The front projecting portion 52 has a plate shape extending in the left-right direction along the right rear axle portion 12R. At least part of the upper surface of the front projecting portion 52 constitutes a load transmission surface 52S. The load transmission surface 52S is positioned below the axle lower surface 12S so as to vertically face the axle lower surface 12S forming part of the lower surface of the right rear axle portion 12R.

Although not shown, the rear overhanging portion 53 and the front overhanging portion 54 have the same structure as the rear overhanging portion 51 and the front overhanging portion 52 except that they are oriented in different directions. . Specifically, the rear projecting portion 53 of the front left transmission portion is a structural member connected to the front left load receiving portion 21L, and has a plate shape projecting rearward from the lower portion of the rear side surface of the front left load receiving portion 21L. have. As a result, the rear protruding portion 53 is arranged so as to straddle in the front-rear direction between the left front load bearing portion 21L and the intermediate portion M1 of the left front axle portion 11L in a plan view. The rear side projecting portion 53 has a plate shape extending in the left-right direction along the left front axle portion 11L. At least part of the upper surface of the rear projection 53 constitutes a load transmission surface 53S. The load transmission surface 53S is positioned below the axle lower surface so as to vertically face the axle lower surface forming part of the lower surface of the left front axle portion 11L. The front projecting portion 54 of the left rear transmission portion is a structural member connected to the left rear load receiving portion 22L, and has a plate shape projecting forward from the lower portion of the front side surface of the left rear load receiving portion 22L. As a result, the front projecting portion 54 is arranged to straddle in the front-rear direction between the left rear load bearing portion 22L and the middle portion M2 of the left rear axle portion 12L in a plan view. The front projecting portion 54 has a plate shape extending in the left-right direction along the left rear axle portion 12L. At least part of the upper surface of the front projecting portion 54 constitutes a load transmission surface 54S. The load transmission surface 54S is positioned below the axle lower surface so as to vertically face the axle lower surface forming part of the lower surface of the left rear axle portion 12L.

In this modification 5, when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the rear overhanging portion 51 and the rear overhanging portion 53 are aligned with the right front axle portion 11R and the left front axle. A downward load component received from the portion 11L can be transmitted to the front right load receiving portion 21R and the front left load receiving portion 21L via the axle lower surface 11S and the load transmitting surfaces 51S and 53S, which face each other in the vertical direction, respectively. The front right load receiving portion 21R and the front left load receiving portion 21L can receive the downward load component and support the front right axle portion 11R and the front left axle portion 11L, respectively.

That is, in this modification 5, when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101, the right front axle portion 11R moves the front overhanging portion 41 and the rear overhanging portion 51 together. The left front axle portion 11L is supported by the left front load receiving portion 21L via the front side projecting portion 43 and the rear side projecting portion 53. Therefore, in the undercarriage 101 according to Modification 5, it is possible to further reduce the bending occurring in the right front axle portion 11R and the left front axle portion 11L as compared with the embodiment shown in FIGS.

In addition, in this modification 5, when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, the front overhanging portion 52 and the front overhanging portion 54 are aligned with the right rear axle portion 12R and the right rear axle portion 12R. A downward load component received from the left rear axle portion 12L is transmitted to the right rear load receiving portion 22R and the left rear load receiving portion 22L via the axle lower surfaces 12S, 12S and the load transmission surfaces 52S, 54S which face each other in the vertical direction, respectively. can do. The right rear load receiving portion 22R and the left rear load receiving portion 22L can receive the downward load component and support the right rear axle portion 12R and the left rear axle portion 12L, respectively.

That is, in this modification 5, when a load is suspended on the upper revolving body 102 on the rear side of the lower traveling body 101, the right rear axle portion 12R has the rear protruding portion 42 and the front protruding portion 52. The left rear axle portion 12L is supported by the left rear load receiving portion 22L via the rear overhang portion 44 and the front overhang portion 54. As shown in FIG. Therefore, in the undercarriage 101 according to Modification 5, it is possible to further reduce the deflection occurring in the right rear axle portion 12R and the left rear axle portion 12L as compared with the embodiment shown in FIGS.

The invention is not limited to the embodiments described above. The present invention includes, for example, the following aspects.

(A) In the above-described embodiment and its modification, the undercarriage 101 includes the expansion/contraction mechanism, but the undercarriage of the present invention is not limited to such an aspect, and may not be provided with the expansion/contraction mechanism. .

(B) In the above embodiment and its modification, the right front load receiving portion 21R and the right rear load receiving portion 22R have shapes that protrude leftward from the right front portion 201 and the right rear portion 202 of the right frame main body 20R, respectively. The present invention is not limited to this, and may have a shape that protrudes leftward from an intermediate portion between the right front axle support portion 27 and the right rear axle support portion 28 of the right frame main body 20R.

In the embodiment and its modification, the left front load receiving portion 21L and the left rear load receiving portion 22L have shapes that protrude to the right from the left front portion 203 and the left rear portion 204 of the left frame body 20L, respectively. Instead, they may each have a shape that protrudes to the right from an intermediate portion between the left front axle support portion 27 and the left rear axle support portion 28 of the left frame main body 20L.

(C) In Modification 3, the right front transmission portion is composed of the front projecting portion 41 and the connection pin P1, and the right rear transmission portion is composed of the rear projection portion 42 and the connection pin P2. The left front transmitting portion is composed of the front projecting portion 43 and the connecting pin P3, and the left rear transmitting portion is composed of the rear projecting portion 44 and the connecting pin P4. It is not limited to modes. The right front transmission portion is composed of only one or more connecting pins P1, the right rear transmission portion is composed of one or more connection pins P2, and the left front transmission portion is composed of one or more connection pins P2. The left rear transmission section may be configured by a pin P3, and may be configured by one or a plurality of connecting pins P4.

(D) In Modified Example 5, the right front transmission portion is composed of a front overhang portion 41 and a rear overhang portion 51, and the right rear transmission portion is composed of a rear overhang portion 42 and a front overhang portion. 52, the left front transmission portion is composed of a front overhang portion 43 and a rear overhang portion 53, and the left rear transmission portion is composed of a rear overhang portion 44 and a front overhang portion. 54, but is not limited to such an aspect. The right front transmission portion is composed only of the rear projection portion 51 , and the right rear transmission portion is composed of only the front projection portion 52 . The left front transmission portion may be composed of only the rear projecting portion 53 , and the left rear transmission portion may be composed of only the front projecting portion 54 .

(E) In the above embodiment, each of the front side surface SF and the rear side surface SR is a plane parallel to the left-right direction and the up-down direction, but it is not limited to such an aspect. If the undercarriage has a structure in which the right frame main body and the left frame main body cannot change their lateral positions with respect to the right front axle portion and the right rear axle portion, the front side surface SF may be a curved surface facing forward. The rear side surface SR may be a curved surface facing the rear side, or may be a curved surface facing the rear side. It may be a plane that is inclined with respect to at least one of the vertical directions.

(F) Specifications of Crane Although the crane according to the embodiment shown in FIG. 1 does not have a jib and struts, the specifications of the crane are not limited to those shown in FIG. A crane according to the present disclosure may be a luffing crane with a jib, front and rear struts, or a fixed jib crane with a jib and one strut. Also, a crane according to the present disclosure may be a crane with a mast instead of a gantry (eg, a large crane).

2L: Left crawler frame 2R: Right crawler frame 10: Car body 11: Front axle 11R: Right front axle portion 11L: Left front axle portion 12: Rear axle 12R: Right rear axle portion 12L: Left rear axle portion 20L: Left frame body 20R : Right frame main body 21L : Left front load receiving portion 21R : Right front load receiving portion 22L : Left rear load receiving portion 22R : Right rear load receiving portion 27 : Right front axle support portion, left front axle support portion 28 : Right rear axle support portion, left Rear axle support 100: mobile crane 101: lower running body 102: upper revolving body C: revolving central axis

Claims (11)

An undercarriage of a mobile crane,
a car body that supports an upper revolving body of the mobile crane so as to be able to revolve around a revolving central axis;
a front axle including a front car body connecting portion connected to the car body, a right front axle portion extending rightward from the front car body connecting portion, and a left front axle portion extending leftward from the front car body connecting portion;
A rear car body connecting portion connected to the car body on the rear side of the front axle, a right rear axle portion extending rightward from the rear car body connecting portion, and a left extending leftward from the rear car body connecting portion. a rear axle including a rear axle portion;
A right crawler including a right frame body extending in the longitudinal direction on the right side of the turning center axis, the right frame body having a right front axle support portion and a right rear axle support portion for supporting the right front axle portion and the right rear axle portion. a frame;
A left frame body including a left frame body extending in the longitudinal direction on the left side of the turning center axis, the left frame body having a left front axle support portion and a left rear axle support portion that support the left front axle portion and the left rear axle portion. a crawler frame;
The right front axle portion has a supported portion supported by the right front axle support portion and an intermediate portion between the supported portion and the front car body connecting portion, and the right rear axle portion includes: A supported portion supported by the right rear axle support portion and an intermediate portion between the supported portion and the rear car body connection portion are provided, and the left front axle portion includes the left front axle support portion. and an intermediate portion between the supported portion and the front car body connection portion, the left rear axle portion being supported by the left rear axle support portion. and an intermediate portion between the supported portion and the rear carbody connecting portion;
The right crawler frame has at least a shape that protrudes leftward from at least one deviated portion of the right frame body that is deviated in the longitudinal direction from the right front axle support portion and the right rear axle support portion. further comprising one right load receiver, the at least one right load receiver receiving a downward load from the intermediate portion of the right front axle portion to support the right front axle portion; configured to receive a downward load from the intermediate portion and support the right rear axle portion;
The left crawler frame has at least a shape protruding rightward from at least one deviated portion of the left frame main body that is deviated in the longitudinal direction from the left front axle support portion and the left rear axle support portion. Further comprising one left load bearing portion, the at least one left load bearing portion receiving a downward load from the intermediate portion of the left front axle portion to support the left front axle portion and to support the left rear axle portion. An undercarriage of a mobile crane configured to receive a downward load from the intermediate portion and support the left rear axle portion. The mobile crane undercarriage according to claim 1,
The at least one detached portion where the at least one right load bearing portion is connected to the right frame main body includes a right front portion, which is a portion of the right frame main body which is on the front side of the right front axle support portion, and a portion of the right frame main body. a right rear portion, which is a portion on the rear side of the right rear axle support portion,
The at least one right load receiving portion includes a right front load receiving portion having a shape projecting leftward from the right front portion and a right rear load receiving portion having a shape projecting leftward from the right rear portion, The right front load bearing portion is configured to receive a downward load component from the intermediate portion of the right front axle portion to support the right front axle portion, and the right rear load bearing portion is configured to support the right front axle portion from the intermediate portion of the right rear axle portion. configured to support the right rear axle portion by receiving a downward load component from the
The at least one detached portion where the at least one left load bearing portion connects to the left frame main body includes a left front portion, which is a portion of the left frame main body on the front side of the left front axle support portion, and a portion of the left frame main body. a left rear portion, which is a portion behind the left rear axle support portion,
The at least one left load bearing portion includes a left front load bearing portion having a shape protruding rightward from the left front portion and a left rear load bearing portion having a shape protruding rightward from the left rear portion, The left front load bearing portion is configured to receive a downward load component from the intermediate portion of the left front axle portion and support the left front axle portion, and the left rear load bearing portion is configured to support the left front axle portion. a mobile crane undercarriage configured to support said left rear axle section under a downward load component from said section. The mobile crane undercarriage according to claim 2,
The right frame main body is configured to be able to change its position in the left-right direction with respect to the right front axle portion and the right rear axle portion,
The undercarriage of a mobile crane, wherein the left frame main body is configured to be able to change its position in the left-right direction with respect to the left front axle portion and the left rear axle portion. The mobile crane undercarriage according to claim 2 or 3,
It is arranged in a plan view so as to straddle the front-rear direction between the right front load bearing portion and the intermediate portion of the right front axle portion, and transmits a downward load received from the right front axle portion to the right front load bearing portion. a right front transmission section configured to allow
In a plan view, it is arranged so as to straddle the front-rear direction between the right rear load bearing portion and the intermediate portion of the right rear axle portion, and the downward load received from the right rear axle portion is received by the right rear load bearing portion. a right rear transmission section configured to be able to transmit to
It is disposed so as to extend in the longitudinal direction between the left front load bearing portion and the middle portion of the left front axle portion in a plan view, and transmits a downward load received from the left front axle portion to the left front load bearing portion. a left front transmission section configured to allow
In a plan view, it is arranged so as to straddle the front-rear direction between the left rear load bearing portion and the intermediate portion of the left rear axle portion, and receives a downward load received from the left rear axle portion through the left rear load bearing portion. a left rear transmission configured to be able to transmit to the mobile crane undercarriage. A mobile crane undercarriage according to claim 4,
each of the right front load receiving portion and the left front load receiving portion has a load receiving surface facing upward,
The right front transmission portion includes a front projecting portion connected to the intermediate portion of the right front axle portion and projecting forward from the intermediate portion,
The left front transmission section includes a front projecting section connected to the intermediate section of the left front axle section and projecting forward from the intermediate section,
the front projecting portion of the right front transmission portion has a load transmission surface configured by a lower surface vertically opposed to the load receiving surface of the right front load receiving portion;
The undercarriage of a mobile crane, wherein the front projecting portion of the left front transmission portion has a load transmission surface configured by a lower surface vertically facing the load receiving surface of the left front load receiving portion. A mobile crane undercarriage according to claim 5,
each of the right rear load receiving portion and the left rear load receiving portion has a load receiving surface facing upward,
the right rear transmission portion includes a rear projection portion connected to the intermediate portion of the right rear axle portion and projecting rearward from the intermediate portion;
The left rear transmission portion includes a rear projection portion connected to the intermediate portion of the left rear axle portion and projecting rearward from the intermediate portion,
the rear projecting portion of the right rear transmission portion has a load transmission surface configured by a lower surface vertically opposed to the load receiving surface of the right rear load receiving portion;
The rear projecting portion of the left rear transmission portion has a load transmission surface configured by a lower surface vertically opposed to the load receiving surface of the left rear load receiving portion. body. The mobile crane undercarriage according to any one of claims 4 to 6,
each of the intermediate portion of the right front axle portion and the intermediate portion of the left front axle portion has an axle lower surface facing downward;
The front right transmission section includes a rear projection section connected to the front right load bearing section and projecting rearward from the front right load bearing section,
The front left transmission portion includes a rear projection portion connected to the front left load bearing portion and projecting rearward from the front left load bearing portion,
the rear projecting portion of the right front transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the right front axle portion;
The rear overhanging portion of the left front transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the left front axle portion. body. A mobile crane undercarriage according to claim 7,
each of the intermediate portion of the right rear axle portion and the intermediate portion of the left rear axle portion has an axle lower surface facing downward;
The right rear transmission section includes a front projecting section connected to the right rear load receiving section and projecting forward from the right rear load receiving section,
The left rear transmission section includes a front projecting section connected to the left rear load receiving section and projecting forward from the left rear load receiving section,
the front projecting portion of the right rear transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the right rear axle portion;
The lower portion of the mobile crane, wherein the front projecting portion of the left rear transmission portion has a load transmission surface configured by an upper surface vertically opposed to the axle lower surface of the intermediate portion of the left rear axle portion. running body. The mobile crane undercarriage according to any one of claims 4 to 8,
the right front transmission portion includes at least one connection pin extending in the longitudinal direction between the right front load bearing portion and the intermediate portion of the right front axle portion to connect them;
The left front transmission section includes at least one connecting pin extending in the longitudinal direction between the left front load receiving section and the middle section of the left front axle section to connect them. A mobile crane undercarriage according to claim 9,
the right rear transmission portion includes at least one connecting pin extending in the longitudinal direction between the right rear load bearing portion and the intermediate portion of the right rear axle portion to connect them;
The left rear transmission section includes at least one connection pin extending in the longitudinal direction between the left rear load bearing section and the middle section of the left rear axle section to connect them. running body. The mobile crane undercarriage according to any one of claims 4 to 10,
the front axle has a front side facing forward,
the rear axle has a rear side facing rearward;
The right front load receiving portion has a right front facing portion that faces the intermediate portion of the right front axle portion in the longitudinal direction, and is positioned forward of the lower traveling structure when a load is suspended on the upper revolving structure. at least part of the load received from the intermediate portion of the right front axle portion can be transmitted from the right front facing portion to the right front portion of the right frame main body;
The left front load receiving portion has a left front facing portion that faces the intermediate portion of the left front axle portion in the longitudinal direction, and is forward of the lower traveling structure when a load is suspended on the upper revolving structure. at least part of the load received from the intermediate portion of the left front axle portion can be transmitted from the left front facing portion to the left front portion of the left frame main body;
The right rear load receiving portion has a right rear facing portion that faces the intermediate portion of the right rear axle portion in the front-rear direction, and a suspended load is suspended from the upper revolving body on the rear side of the lower traveling body. at least a portion of the load received from the intermediate portion of the right rear axle portion when the vehicle is engaged with the right rear axle portion can be transmitted from the right rear facing portion to the right rear portion of the right frame main body;
The left rear load receiving portion has a left rear facing portion that faces the intermediate portion of the left rear axle portion in the front-rear direction, and a suspended load is suspended from the upper revolving body on the rear side of the lower traveling body. at least a part of the load received from the intermediate portion of the left rear axle portion when the vehicle is moved can be transmitted from the left rear facing portion to the left rear portion of the left frame main body; The undercarriage of a mobile crane.

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