JP2022187522A - Lower traveling body of mobile crane - Google Patents

Abstract

To provide a lower traveling body of a mobile crane that can reduce deformations that are caused when a suspended load is suspended from an upper turning body on the front side or the rear side of the lower traveling body.SOLUTION: In a lower traveling body 101 of a mobile crane, a right-front load transmission part 21R and a left-front load transmission part 21L are configured so that front-side loads can be respectively transmitted from a right-front opposing part ST1 and a left-front opposing part ST3 to a right-front transmission site 201 of a right frame main body 20R and a left-front transmission site 203 of a left frame main body 20L, and a right-rear load transmission part 22R and a left-rear load transmission part 22L are configured so that rear-side loads can be respectively transmitted from a right-rear opposing part ST2 and a left-rear opposing part ST4 to a right-rear transmission site 202 of the right frame main body 20R and a left-rear transmission site 204 of the left frame main body 20L.SELECTED DRAWING: Figure 3

Description

The present invention relates to an undercarriage for mobile cranes.

Conventionally, mobile cranes are known (for example, Patent Documents 1 and 2). This mobile crane includes an undercarriage that can travel on the ground, and an upper revolving 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.

For example, in the mobile crane of Patent Document 1, the distance from the turning center axis of the pair of crawler frames is adjusted in the left-right direction in order to increase the safety when the load is lifted via the lifting rope of the working device. In order to reduce the transportation width when the mobile crane is transported, it is provided with an extension/reduction mechanism for laterally reducing the distance from the turning center axis of the pair of crawler frames. In a mobile crane equipped with such an expansion/retraction mechanism, each crawler frame must be slid, for example, in the left-right direction along the front axle and the rear axle. Each crawler frame has a pair of axle support portions that slidably support the front axle and the rear axle.

JP 2018-70339 A JP 2017-171090 A

As described above, in the undercarriage having the structure in which the front axle and the rear axle extending in parallel from the car body in the left-right direction connect the car body and the left and right crawler frames, the rigidity in the front-rear direction is lower than the rigidity in the left-right direction. . Therefore, in the lifting operation of the mobile crane (crane operation), when the load is suspended from the upper rotating body at the front side or the rear side of the lower traveling body, the front side portion or the rear side portion of the car body is displaced downward. The amount is likely to be greater than the amount by which the right or left portion of the carbody is displaced downwards when the load is suspended from the upper revolving structure on the side of the undercarriage.

Specifically, when a load is suspended from the upper revolving structure on the front side or rear side of the lower traveling structure, the load applied to the car body from the upper revolving structure causes torsional deformation and deflection at the front and rear axles. Deformation such as deformation occurs, and deformation also occurs in the car body, so that the front side portion or the rear side portion of the car body tends to be displaced downward. Also, the left and right crawler frames are likely to be deformed so as to follow the deformation of the front and rear axles. As a result, there is a difference in the degree of deformation that occurs in the undercarriage as the swing position of the upper swing structure changes, and this causes the position of the suspended load to fluctuate up and down. There is Therefore, it is desirable to reduce deformation of the undercarriage when a load is suspended from the upper revolving body on the front side or rear side of the undercarriage by improving the longitudinal rigidity of the undercarriage. be

Patent Literature 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. However, since various members such as a swing motor for swinging the upper swing body, gears, hydraulic piping, and electrical wiring are arranged around the trunk of the car body, it is difficult to dispose the pair of reinforcing members. In some cases, there may not be enough space. In this case, the effect of suppressing deformation of the car body by the pair of reinforcing members is limited.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an undercarriage that is less deformed when a load is suspended from the upper revolving body on the front side or rear side of the undercarriage. do.

Provided are a mobile crane undercarriage, a carbody that supports the mobile crane superstructure for pivoting about a pivot axis, and right and left sides of the carbody, respectively. A front axle that extends and has a front side facing forward, and a rear axle that extends to the right and left from the car body behind the front axle and has a rear side facing rearward. a right crawler frame including a right frame body, a right front load transmission portion, and a right rear load transmission portion extending in the front-rear direction on the right side of the turning center axis; and a left crawler frame extending in the front-rear direction on the left side of the turning center axis. a left crawler frame including a frame body, a left front load transmission section, and a left rear load transmission section, wherein the right frame body includes a right front axle support section and a right rear axle support that support the front axle and the rear axle, respectively. the left frame main body has a left front axle support portion and a left rear axle support portion that support the front axle and the rear axle, respectively; A right front facing portion having a shape protruding leftward from a right front transmission portion which is a portion on the front side of the right front axle support portion and facing the front side surface of the front axle in the longitudinal direction on the left side of the right front axle support portion. a front side load, which is a load that the car body receives from the upper swing body when a load is suspended on the upper swing body on the front side of the lower traveling body, is transmitted from the right front facing portion to the right front side load The right rear load transmission portion protrudes leftward from a right rear transmission portion, which is a portion of the right frame main body rearward of the right rear axle support portion. having a right rear facing portion that faces the rear side surface of the rear axle in the front-rear direction on the left side of the right rear axle support portion, and the upper rotating body on the rear side of the lower traveling body. the rear side load, which is the load that the car body receives from the upper revolving structure when a load is suspended from the hoist, can be transmitted from the right rear facing portion to the right rear transmission portion, The left front load transmission portion has a shape that protrudes rightward from a left front transmission portion, which is a portion of the left frame main body on the front side of the left front axle support portion, and the front axle is located on the right side of the left front axle support portion. has a left front facing portion facing the front and back direction on the front side surface of , the front side load can be transmitted from the left front facing portion to the left front transmission portion, and the left rear load transmission portion is positioned rearward of the left rear axle support portion in the left frame main body. has a shape projecting to the right from the left rear transmission portion which is the portion of and has a left rear facing portion facing the rear side surface of the rear axle in the front-rear direction on the right side of the left rear axle support portion, The rear side load is configured to be able to be transmitted from the left rear facing portion to the left rear transmission portion.

In the undercarriage of this mobile crane, the front right load transmission section and the front left load transmission section transmit the front load that the car body receives from the upper revolving body from the front right axle support section and the front left axle support section to the front right axle support section and the front left axle support section. It is possible to transmit to the right front transmission part and the left front transmission part on the front side of the part. That is, the right front load transmission portion and the left front load transmission portion can support the front axle on the front side of the right front axle support portion and the left front axle support portion that support the front axle. As a result, deformation such as torsional deformation is suppressed in the front axle, and deformation in the car body and rear axle is also suppressed. This makes it possible to effectively suppress downward displacement of the front portion of the carbody. In addition, when deformation of the front and rear axles is suppressed, deformation of the left and right crawler frames is also suppressed.

Similarly, the right rear load transmission section and the left rear load transmission section transmit the rear load received by the car body from the upper swing body from the right rear facing section and the left rear facing section to the right rear axle support section and the left rear axle support section. It is possible to transmit to the right rear transmission part and the left rear transmission part on the rear side of the part. That is, the right rear load transmission portion and the left rear load transmission portion can support the rear axle behind the right rear axle support portion and the left rear axle support portion that support the rear axle. As a result, deformation such as torsional deformation is suppressed in the rear axle, and deformation in the car body and front axle is also suppressed. This makes it possible to effectively suppress downward displacement of the rear portion of the carbody. In addition, when deformation of the rear axle and the front axle is suppressed, deformation of the left and right crawler frames is also suppressed.

Therefore, in this undercarriage, it is possible to reduce deformation of the undercarriage when a load is suspended from the upper revolving body on the front side or the rear side of the undercarriage. This makes it possible to suppress the difference in the degree of deformation that occurs in the lower traveling body due to changes in the revolving position of the upper revolving body, and the change in the revolving position of the upper revolving body. It makes it possible to suppress the position from fluctuating up and down. As a result, it is possible to suppress deterioration in the workability of the lifting work.

The right front axle support portion and the right rear axle support portion support the front axle and the rear axle, respectively, so that the position of the right frame main body in the left-right direction with respect to the front axle and the rear axle can be changed. wherein the left front axle support part and the left rear axle support part are arranged so as to change the position of the left frame main body in the left-right direction with respect to the front axle and the rear axle. Preferably, they are arranged to respectively support the rear axles.

In this aspect, although the expansion/reduction mechanism capable of expanding or contracting the distance from the turning center axis of the crawler frame in the left-right direction is provided, the suspended load is positioned above the lower traveling body on the front side or the rear side. It is possible to reduce the deformation that occurs in the undercarriage when suspended from the revolving body.

In the undercarriage of the mobile crane, at least one of the right front facing portion and the left front facing portion is configured to contact the front side surface of the front axle when the car body receives the front load. may be

In this aspect, at least one of the right front facing portion and the left front facing portion can receive the front load from the front side by contacting the front side when the car body receives the front load. As a result, the front load is transmitted to the corresponding transmission portion of the right front transmission portion and the left front transmission portion.

Similarly, at least one of the right rear facing portion and the left rear facing portion may be configured to contact the rear side surface of the rear axle when the car body receives the rear load.

In this aspect, at least one of the right rear facing portion and the left rear facing portion can receive the rear load from the rear side surface by contacting the rear side surface when the car body receives the rear side load. As a result, the rear load is transmitted to the corresponding one of the right rear transmission portion and the left rear transmission portion.

The undercarriage of the mobile crane further includes at least one front-side intervening member, and the at least one front-side intervening member includes at least one facing portion selected from the right front facing portion and the left front facing portion, and the front facing portion. It is detachably arranged in a gap formed between the axle and the front side surface, and is configured to contact both the front side surface and the at least one opposing portion when the car body receives the front side load. may have been

In this aspect, even when a gap is formed between the at least one facing portion and the front side surface, the at least one facing portion is positioned so that when the car body receives the front side load, the front side load is applied. can be received via the at least one front intervening member. As a result, the front load is transmitted to the corresponding one of the right front transmission portion and the left front transmission portion. Further, by removing the at least one front intervening member from the gap, the lateral positions of the right crawler frame and the left crawler frame can be changed with respect to the front axle and the rear axle.

Similarly, the undercarriage of the mobile crane further includes at least one rear intervening member, and the at least one rear intervening member is at least one of the right rear facing portion and the left rear facing portion. is detachably arranged in a gap formed between one opposing portion and the rear side surface of the rear axle, and when the car body receives the rear side load, the rear side surface and the at least one opposing You may be comprised so that both sides of a part may be touched.

In this aspect, even when a gap is formed between the at least one facing portion and the rear side surface, the at least one facing portion is positioned so that when the car body receives a rear-side load, the rear side of the at least one facing portion may A side load can be received via the at least one rear intervening member. Thereby, the rear load is transmitted to the corresponding one of the right rear transmission portion and the left rear transmission portion. Further, by removing the at least one rear intervening member from the gap, the lateral positions of the right crawler frame and the left crawler frame can be changed with respect to the front axle and the rear axle.

The undercarriage of the mobile crane further includes at least one front connecting member, and the at least one front connecting member includes at least one facing portion selected from the front right facing portion and the front left facing portion, and the front facing portion. It may be detachably attached to the axle and configured to connect the at least one facing portion and the front axle.

In this aspect, when the carbody receives a front load, the at least one facing portion can receive the front load via the at least one front connection member. As a result, the front load is transmitted to the transmission portion corresponding to the facing portion to which the front connecting member is attached, of the right front transmission portion and the left front transmission portion. Further, by removing the at least one front connecting member, the lateral positions of the right crawler frame and the left crawler frame can be changed with respect to the front axle and the rear axle.

In the case of this aspect, it is more preferable that the at least one front connecting member is configured by a connecting pin, and the axial direction of the connecting pin is oriented in the front-rear direction.

In this aspect, since the connecting pin faces in the front-rear direction, the crawler frame including the facing portion to which the connecting pin is attached is displaced in the left-right direction with respect to the front axle. Displacement in a direction intersecting the axial direction can be effectively restricted. Therefore, in this aspect, the connection pin has the function of transmitting the front side load to the right front load transmission section or the left front load transmission section and the left and right movement of the crawler frame with respect to the front axle when the mobile crane is used to lift a load. It also has the function of effectively restricting directional displacement. Further, in this aspect, it is possible to omit or simplify the reinforcement measures for suppressing the lateral displacement of the crawler frame with respect to the front axle.

Similarly, the undercarriage of the mobile crane further includes at least one rear connecting member, and the at least one rear connecting member is at least one of the right rear facing portion and the left rear facing portion. may be detachably attached to two opposing portions and the rear axle, and configured to connect the at least one opposing portion and the rear axle.

In this aspect, when the car body receives a rear load, the at least one facing portion can receive the rear load via the at least one rear connection member. As a result, the rear load is transmitted to the right rear transmission portion and the left rear transmission portion corresponding to the facing portion to which the rear connection member is attached. Further, by removing the at least one rear connecting member, the lateral positions of the right crawler frame and the left crawler frame can be changed with respect to the front axle and the rear axle.

In the case of this aspect, it is more preferable that the at least one rear connecting member is configured by a connecting pin, and the axial direction of the connecting pin is oriented in the front-rear direction.

In this aspect, since the connecting pin faces in the front-rear direction, the crawler frame including the facing portion to which the connecting pin is attached is displaced in the left-right direction with respect to the rear axle. Displacement in a direction intersecting the axial direction can be effectively restricted. Therefore, in this aspect, the connection pin has the function of transmitting the rear load to the right rear load transmission part or the left rear load transmission part and the function of transmitting the rear load to the right rear load transmission part or the left rear load transmission part, and It also has a function of effectively restricting lateral displacement of the frame. Further, in this aspect, it is possible to omit or simplify reinforcing measures for suppressing lateral displacement of the crawler frame with respect to the rear axle.

The undercarriage of the mobile crane includes a pair of right wheels rotatably supported by the front and rear ends of the right frame body, and rotatable by the front and rear ends of the left frame body. and a plurality of right rollers spaced apart in the front-rear direction between the pair of right wheels and rotatably supported at the bottom of the right frame main body, A plurality of right rollers including a right front end roller positioned furthest and a right rear end roller positioned rearmost; a plurality of left rollers rotatably supported at the lower portion, the plurality of left rollers including a left front end roller positioned furthest and a left rear end roller positioned rearmost; In a plan view, a right front straight line that passes through any point included in the right front facing portion and any point included in the right front transmission portion is on the front side of the right front end roller or the right front end roller. The left front load transmission portion is configured to pass through the left front straight line passing through any point included in the left front facing portion and any point included in the left front transmission portion in a plan view. It is preferable that the left front end roller or the front side of the left front end roller be passed through.

Normally, the right front end roller is arranged relatively close to the front end of the right frame main body, and the left front end roller is arranged relatively close to the front end of the left frame main body. Therefore, by configuring the right front load transmission section so that the right front straight line and the right front end roller have the above-described positional relationship, the portion where the right front load transmission section transmits the front load to the right frame main body and the right frame main body The distance in the front-rear direction from the front end of the can be effectively reduced. Further, by configuring the left front load transmission section so that the left front straight line and the left front end roller have the above-described positional relationship, the portion where the left front load transmission section transmits the front load to the left frame main body and the left frame main body The distance in the front-rear direction from the front end of the can be effectively reduced. This makes it possible to reduce the deflection caused in the front part of the right frame main body and the front part of the left frame main body when the load is suspended from the upper revolving structure on the front side of the undercarriage.

Further, in this aspect, the right front load transmission portion is provided in a portion of the right frame main body relatively close to the front end thereof, i.e., a portion of the right frame main body corresponding to the right front end roller or a portion on the front side thereof. It has a structure capable of being supported by the frame body, and the front axle is supported by the right front load transmission section having such a structure. Similarly, the left front load transmission section is configured such that a portion of the left frame body relatively close to the front end thereof, i.e., a portion of the left frame body corresponding to the left front end roller or a portion further forward thereof, is moved by the left frame body. The front axle has a supportable structure, and the front axle is supported by the left front load transmission part having such a structure. As a result, deformation of the front axle is more effectively suppressed, and as a result, downward displacement of the front portion of the car body is more effectively suppressed.

Here, when the car body receives a relatively large front load from the upper revolving body, the right front end roller and the left front end roller become approximate tipping fulcrums (front tipping fulcrums). It is preferable that the straight line passes through the front end roller, and the left front straight line is a straight line that passes through the left front end roller in plan view.

In this aspect, the right front load transmission section and the left front load transmission section directly transmit the front load to the portion of the right frame main body corresponding to the front overturning fulcrum and the portion of the left frame main body corresponding to the front overturning fulcrum, respectively. can do. This makes it possible to reduce the deflection caused in the front portion of the right frame body and the front portion of the left frame body due to the front load.

Further, it is preferable that the right front straight line is a straight line further passing through the turning center axis in plan view, and the left front straight line is a straight line further passing through the turning center axis in plan view.

In this aspect, in a plan view, any point included in the right front facing portion and any point included in the right front transmission portion can be positioned on the right front straight line passing through the turning center axis and the right front end roller. In plan view, any point included in the left front facing portion and any point included in the left front transmission portion can be positioned on the left front straight line passing through the turning center axis and the left front end roller. As a result, the path along which the front load is transmitted to the right frame main body by the right front load transmission section can be made closer to the direction from the turning center axis toward the right front end roller, and the front load is transmitted to the left frame main body by the left front load transmission section. It is possible to make the path to be closer to the direction from the turning center axis to the left front end roller. This allows the front load to be efficiently transmitted to the portion of the right frame body corresponding to the front tipping fulcrum and the portion of the left frame body corresponding to the front tipping fulcrum, respectively.

Further, the front right load transmission portion has a front right continuous portion that continues from the front right facing portion to the front right transmission portion along the front right straight line in plan view, and the front left load transmission portion has a front left straight line in plan view. It is preferable to have a left front continuous portion that continues along from the left front facing portion to the left front transmission portion.

In this aspect, the right front continuous portion is continuous from the right front facing portion to the right front transmission portion in plan view without interruption, and the left front continuous portion is continuous from the left front facing portion to the left front transmission portion in plan view without interruption. The front load received by the facing portion and the front left facing portion is continuously and efficiently transmitted to the front right transmission portion and the front left transmission portion along the front right continuous portion and the front left continuous portion.

In the undercarriage of the mobile crane, the right rear load transmission portion is a straight line passing through any point included in the right rear facing portion and any point included in the right rear transmission portion in a plan view. The right rear straight line passes through the right rear end roller or the rear side of the right rear end roller, and the left rear load transmission portion is included in the left rear facing portion in plan view. It is preferable that a left rear straight line that is a straight line passing through a point and any point included in the left rear transmission portion passes through the left rear end roller or the rear side of the left rear end roller. .

Normally, the right rear end roller is arranged relatively close to the rear end of the right frame main body, and the left rear end roller is arranged relatively close to the rear end of the left frame main body. Therefore, by configuring the right rear load transmission section so that the right rear straight line and the right rear end roller have the above-described positional relationship, the right rear load transmission section transmits the rear load to the right frame main body. The distance in the front-rear direction between the portion and the rear end of the right frame main body can be effectively reduced. Further, the left rear load transmission section is configured such that the left rear straight line and the left rear end roller have the above positional relationship, so that the left rear load transmission section transmits the rear load to the left frame main body. The distance in the front-rear direction between the portion and the rear end of the left frame main body can be effectively reduced. This makes it possible to reduce the bending that occurs in the rear portion of the right frame main body and the rear portion of the left frame main body when a load is suspended from the upper revolving structure on the rear side of the undercarriage. do.

Further, in this aspect, the right rear load transmission portion is a portion of the right frame main body relatively close to the rear end portion, that is, a portion of the right frame main body corresponding to the right rear end roller or a portion behind it. and the rear axle is supported by the right rear load transmission section having such a structure. Similarly, the left rear load transmission portion is arranged in a portion of the left frame body relatively close to the rear end, that is, a portion of the left frame body corresponding to the left rear end roller or a portion further rearward thereof. It has a structure capable of being supported by the frame body, and the rear axle is supported by the left rear load transmission section having such a structure. As a result, deformation of the rear axle is more effectively suppressed, and as a result, downward displacement of the rear portion of the car body is more effectively suppressed.

Here, when the car body receives a relatively large rear load from the upper revolving structure, the right rear end roller and the left rear end roller become approximate overturning fulcrums (rear overturning fulcrums), so the right rear straight line is It is preferable that the straight line passes through the right rear end roller in plan view, and the left rear straight line is a straight line that passes through the left rear end roller in plan view.

In this aspect, the right rear load transmission section and the left rear load transmission section transmit the rear load to the portion of the right frame main body corresponding to the rear overturning fulcrum and the portion of the left frame main body corresponding to the rear overturning fulcrum. Each can be transmitted directly. This allows the rear portion of the right frame body and the rear portion of the left frame body to flex less due to the rear load.

Moreover, it is preferable that the right rear straight line is a straight line further passing through the turning center axis in plan view, and the left rear straight line is a straight line further passing through the turning center axis in plan view.

In this aspect, in a plan view, any point included in the right rear facing portion and any point included in the right rear transmission portion are positioned on the right rear straight line passing through the turning center axis and the right rear end roller. In a plan view, any point included in the left rear facing portion and any point included in the left rear transmission portion are aligned on the left rear straight line passing through the turning center axis and the left rear end roller. can be positioned. As a result, the path through which the rear load is transmitted to the right frame body by the right rear load transmission section can be made closer to the direction from the turning center axis toward the right rear end roller, and the rear load is transmitted to the left by the left rear load transmission section. The path of transmission to the frame main body can be made closer in the direction from the turning center axis to the left rear end roller. This allows the rear load to be efficiently transmitted to the portion of the right frame body corresponding to the rear tipping fulcrum and the portion of the left frame body corresponding to the rear tipping fulcrum, respectively.

Further, the right rear load transmission portion has a right rear continuous portion that continues from the right rear facing portion to the right rear transmission portion along the right rear straight line in plan view, and the left rear load transmission portion includes: It is preferable to have a left rear continuous portion that continues from the left rear facing portion to the left rear transmission portion along the left rear straight line in plan view.

In this aspect, the right rear continuous portion is continuous from the right rear facing portion to the right rear transmission portion in plan view, and the left rear continuous portion is continuous from the left rear facing portion to the left rear transmission portion in plan view. Therefore, the rear load received by the right rear facing portion and the left rear facing portion is continuously and efficiently transmitted to the right rear transmission portion and the left rear transmission portion along the right rear continuous portion and the left rear continuous portion. be.

The present invention provides an undercarriage that is less deformed when a load is suspended from the upper rotating 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 1st Embodiment. It is a top view which shows the undercarriage which concerns on 1st Embodiment. It is a top view which shows the undercarriage which concerns on 1st Embodiment. 4 is a schematic cross-sectional view taken along line VV of FIG. 3; FIG. 6 is an enlarged cross-sectional view of a portion surrounded by a dashed line VI in FIG. 5. FIG. It is a top view which shows the undercarriage which concerns on 2nd Embodiment. FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII of FIG. 7; 9 is an enlarged cross-sectional view of a portion surrounded by a dashed line IX in FIG. 8. FIG. It is a top view which shows the undercarriage which concerns on 3rd Embodiment. 11 is a schematic cross-sectional view taken along line XI-XI of FIG. 10; FIG.

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. In the specific example shown in FIG. 1, the boom 106 is a lattice boom having a lattice structure, but is not limited to this, and may be a telescopic boom whose length can be changed by expanding and contracting.

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 first 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 traveling device and the left traveling device is a device for traveling 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 connection 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 connection 16 is interposed between these axles 11,12. The connecting portion 16 is connected to the front axle 11, the rear axle 12 and the tubular portion 14, so that the connecting portion 16, the front axle 11, the rear axle 12 and the tubular portion 14 form an integral structure. The connecting 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.

As shown in FIG. 3, the front axle 11 has a forward facing front side SF, and as shown in FIGS. 2 and 3, the rear axle 12 has a rearward facing rear side SR. 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.

The right travel device includes a right crawler frame 2R, a pair of right wheels 23R and 24R, a right crawler belt 25R, a plurality of right rollers 26, and a travel drive device 29 (see FIG. 1). Similarly, the left travel device includes a left crawler frame 2L, a pair of left wheels 23L and 24L, a left crawler belt 25L, a plurality of left rollers 26, and a travel drive device 29.

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, each of the right front axle support portion 27 and the right rear axle support portion 28 includes a reinforcing portion 27a annularly protruding leftward from the left side surface of the right frame main body 20R positioned around the axle support portion. 28a. These reinforcing portions 27a and 28a are provided so as to surround the front axle 11 and the rear axle 12. As shown in FIG. As a result, 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 right wheels 23R, 24R are rotatably supported by the front and rear ends of the right frame main body 20R. In this embodiment, the right wheel 23R located on the front side is configured by an idler, and the right wheel 24R located on the rear side is configured by a drive tumbler. This drive tumbler is connected to the 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 the pair of right wheels 23R and 24R and is rotatable. In other words, the right crawler belt 25R is endlessly supported by the pair of right 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 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 wheel 24R is given 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 wheel 23R constituted by an idler rotates following the right crawler belt 25R.

A plurality of right rollers 26 are rotatably supported under the right frame body 20R of the right crawler frame 2R. The plurality of right rollers 26 are arranged at intervals in the front-rear direction between the pair of right 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 positioned foremost among the plurality of right rollers 26 (in this embodiment, the right roller 26 closest to the right wheel 23R) is referred to as a right front end roller 261, and among the plurality of right rollers 26 The rearmost right roller 26 (in this embodiment, the right roller 26 closest to the right wheel 24R) is called a right rear end roller 262 .

The structure of the pair of left 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 pair of right wheels 23R, 24R, the right crawler belt 25R, and the plurality of right rollers 26 in the right traveling device described above. , except that it is bilaterally symmetrical, detailed description thereof will be omitted. In addition, below, the left roller 26 (in this embodiment, the left roller 26 closest to the left 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 The rearmost left roller 26 (in this embodiment, the left roller 26 closest to the left 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 frame body 20R of the right crawler frame 2R, and the tip of the left crawler moving cylinder 15L is fixed to the left frame body 20L of the left crawler frame 2L. Accordingly, the right crawler frame 2R of the right traveling device is displaced in the horizontal direction in accordance with the expansion and contraction of the right crawler moving cylinder 15R, and the left traveling device is displaced in accordance with 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 undercarriage 101 according to the present embodiment includes an expansion/reduction mechanism capable of expanding or reducing the distance from the turning center axis C of the right crawler frame 2R and the left crawler frame 2L in the left-right direction as described above. , deformation such as deflection caused in the car body 10, the front axle 11, the rear axle 12, the crawler frames 2R, 2L, etc. due to the front side load and the rear side load is reduced by providing the load transmission structure described below. be able to. The front side load is the load that the carbody 10 receives from the upper revolving body 102 when a load is hung from the hook device 109 of the upper revolving body 102 on the front side of the lower traveling body 101. The rear side load is This is the load that the carbody 10 receives from the upper revolving body 102 when the load is hung from the hook device 109 of the upper revolving body 102 behind the lower traveling body 101 . The load transmission structure of the undercarriage 101 will be described in detail below.

In the mobile crane 100 including the lower traveling body 101 as shown in FIGS. , has an arc shape in a side view. Therefore, the front and rear ends of the crawler belts 25R and 25L are lifted from the ground. In the right crawler belt 25R and the left crawler belt 25L, the right front end roller 261 and the left front end roller 261 serve as a tipping fulcrum (front tipping fulcrum) when the car body 10 receives the front load from the upper revolving body 102. Corresponding portions, which serve as a tipping fulcrum (rear tipping fulcrum) when the car body 10 receives the rear load from the upper revolving body 102, correspond to the right rear end roller 262 and the left rear end roller 262. It is a part to do.

In the lower traveling body 101 according to the present embodiment, the right crawler frame 2R further includes a right front load transmission portion 21R and a right rear load transmission portion 22R, and the left crawler frame 2L further includes a left front load transmission portion 21L and a left and a rear load transmission portion 22L.

The right front load transmission portion 21R of the right crawler frame 2R has a shape projecting leftward from a right front transmission portion 201, which is a portion of the right frame body 20R on the front side of the right front axle support portion 27. It is supported by the right frame main body 20R. The right front load transmission portion 21R has a right front facing portion ST1 that faces the front side surface SF of the front axle 11 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 transmission portion 21R is configured to be able to transmit the front side load from the right front facing portion ST1 to the right front transmission portion 201. As shown in FIG. The front load transmitted by the right front load transmission portion 21R from the right front facing portion ST1 to the right front transmission portion 201 is transferred from the car body 10 to the upper revolving body when a load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101. A portion of the total load received from 102 .

The right rear load transmission portion 22R of the right crawler frame 2R has a shape protruding leftward from a right rear transmission portion 202, which is a portion behind the right rear axle support portion 28 of the right frame main body 20R. The rear transmission portion 202 is supported by the right frame main body 20R. The right rear load transmission portion 22R has a right rear facing portion ST2 that faces the rear side surface SR of the rear axle 12 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 transmission portion 22R is configured to be able to transmit the rear load from the right rear facing portion ST2 to the right rear transmission portion 202. As shown in FIG. The rear load that the right rear load transmission portion 22R transmits from the right rear facing portion ST2 to the right rear transmission portion 202 is applied to the car body when a load is suspended on the upper revolving body 102 behind the lower traveling body 101. 10 is a fraction of the total load received from the upper rotating body 102 .

The left front load transmission portion 21L of the left crawler frame 2L has a shape protruding rightward from a left front transmission 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. It is supported by the left frame body 20L. The left front load transmission portion 21L has a left front facing portion ST3 that faces the front side surface SF of the front axle 11 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 transmission portion 21L is configured to be able to transmit the front side load from the left front facing portion ST3 to the left front transmission portion 203. As shown in FIG. The front load transmitted by the left front load transmission portion 21L from the left front facing portion ST3 to the left front transmission 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. A portion of the total load received from 102 .

The left rear load transmission portion 22L of the left crawler frame 2L has a shape protruding rightward from a left rear transmission portion 204, which is a portion behind the left rear axle support portion 28 of the left frame main body 20L. The rear transmission portion 204 is supported by the left frame main body 20L. The left rear load transmission portion 22L has a left rear facing portion ST4 that faces the rear side surface SR of the rear axle 12 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 transmission portion 22L is configured to be able to transmit the rear load from the left rear facing portion ST4 to the left rear transmission portion 204. As shown in FIG. The rear load that the left rear load transmission portion 22L transmits from the left rear facing portion ST4 to the left rear transmission portion 204 is applied to the car body when a load is suspended on the upper revolving body 102 behind the lower traveling body 101. 10 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 transmission portion 21R of the right crawler frame 2R and the left front load transmission portion 21L of the left crawler frame 2L are configured such that the car body 10 is an upper revolving body. The front load received from 102 can be transmitted from right front facing portion ST1 and left front facing portion ST3 to right front transmission portion 201 and left front transmission portion 203 on the front side of right front axle support portion 27 and left front axle support portion 27, respectively. is. Specifically, when the car body 10 receives the front load from the upper revolving body 102, the front load is transmitted to the front axle 11 and transferred from the front side surface SF of the front axle 11 to the right front facing portion of the right front load transmission portion 21R. The load is transmitted to ST1 and to the left front facing portion ST3 of the left front load transmission portion 21L, respectively. The right front load transmission portion 21R is a member that continues from the right front facing portion ST1 to the right front transmission portion 201, and the left front load transmission portion 21L is a member that continues from the left front facing portion ST3 to the left front transmission portion 203. The load transmission portion 21R and the left front load transmission portion 21L can transmit the front side load transmitted to the right front facing portion ST1 and the left front facing portion ST3, respectively, to the right front transmission portion 201 and the left front transmission portion 203, respectively.

Similarly, the right rear load transmission portion 22R of the right crawler frame 2R and the left rear load transmission portion 22L of the left crawler frame 2L transfer the rear load that the car body 10 receives from the upper revolving body 102 to the right rear facing portion ST2 and the left rear load transmission portion 22L. It is possible to transmit from the left rear facing portion ST4 to the right rear transmission portion 202 and the left rear transmission 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, the rear load is transmitted to the rear axle 12, and then from the rear side surface SR of the rear axle 12 to the right rear load transmission portion 22R. The load is transmitted to the right rear facing portion ST2 and the left rear facing portion ST4 of the left rear load transmission portion 22L, respectively. The right rear load transmission portion 22R is a member that continues from the right rear facing portion ST2 to the right rear transmission portion 202, and the left rear load transmission portion 22L is a member that continues from the left rear facing portion ST4 to the left rear transmission portion 204. Therefore, the right rear load transmission portion 22R and the left rear load transmission portion 22L transmit the front load transmitted to the right rear facing portion ST2 and the left rear facing portion ST4, respectively, to the right rear transmission portion 202 and the left rear transmission portion 202. Each can be communicated to a portion 204 .

On the other hand, in the conventional lower traveling body which is not equipped with the above-described load transmission section, the front load received by the car body from the upper revolving body is transmitted from the front axle to the right front axle support section of the right crawler frame and the left front axle of the left crawler frame. transmitted to the support. That is, in the conventional undercarriage, the portion where the front load is transmitted from the front axle to the right crawler frame is not in front of the right front axle support portion, and the front load is transmitted from the front axle to the left crawler frame. There is no part in front of the left front axle support. Similarly, the rear load that the carbody receives from the upper revolving structure 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. That is, in the conventional undercarriage, the portion where the rear load is transmitted from the rear axle to the right crawler frame is not behind the right rear axle support portion, and the rear load is transferred from the rear axle to the left crawler frame. There is no transmission site behind the left rear axle support.

In the undercarriage 101 according to the present embodiment, the right front load transmission portion 21R and the left front load transmission portion 21L support the front axle 11 on the front side of the right front axle support portion 27 and the left front axle support portion 27 that support the front axle 11. be able to. As a result, deformation such as torsional deformation is suppressed in the front axle 11 , and deformation in the car body 10 and the rear axle 12 is also suppressed. The torsional deformation of the front axle 11 is, for example, deformation that bends the upper surface of the front axle 11 forward. Similarly, the right rear load transmission portion 22R and the left rear load transmission portion 22L can support the rear axle 12 behind the right rear axle support portion 28 and the left rear axle support portion 28 that support the rear axle 12. . As a result, deformation such as torsional deformation is suppressed in the rear axle 12 , and deformation in the car body 10 and the front axle 11 is also suppressed. The torsional deformation of the rear axle 12 is a deformation that bends the upper surface of the rear axle rearward. Moreover, when deformation of the front axle 11 and the rear axle 12 is suppressed, deformation of the left and right crawler frames 2R and 2L is also suppressed.

In addition, in the undercarriage 101 according to the present embodiment, the front load is transmitted to the portion corresponding to the front tipping fulcrum 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 rear overturning fulcrum and the part to which the rear load is transmitted can be made smaller than in the conventional undercarriage. can be made smaller than in conventional undercarriages. 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 front load, and the deflection that occurs in the rear portions of the right frame body 20R and the left frame body 20L due to the rear load. To make it possible to reduce the generated deflection as compared with the conventional one.

In the present embodiment, the right front load transmission portion 21R of the right crawler frame 2R is a straight line passing through the point A1 included in the right front facing portion ST1 and the point A2 included in the right front transmission portion 201 in plan view shown in FIG. has a shape such that the right front straight line LA passes through the right front end roller 261 . The right front straight line LA is a straight line that passes through the right front end roller 261 and the turning center axis C in plan view. The right front load transmission portion 21R is provided at a position overlapping the right front straight line LA. In the present embodiment, the right front straight line LA passes through the central position of the right front end roller 261 in the width direction (horizontal direction) of the right front end roller 261 and the rotation center axis C in plan view. A straight line. The front right load transmission portion 21R provided at such a position can transmit the front load to a portion closer to the portion of the right frame main body 20R corresponding to the front tipping fulcrum. In addition, the right front load transmission portion 21R is configured so that the right front straight line LA and the right front end roller 261 have the above-described positional relationship, so that the right front load transmission portion 21R is positioned on the right front end roller 261 of the right frame main body 20R. The front axle 11 has a structure capable of being supported by the right frame main body 20R at corresponding portions, and the front axle 11 is supported by the right front load transmission portion 21R having such a structure. As a result, deformation of the front axle 11 and the carbody 10 is more effectively suppressed. Further, the right front load transmission portion 21R is configured so that the right front straight line LA and the right front end roller 261 have the above-described positional relationship, so that the deflection that occurs in the front portion of the right frame main body 20R due to the front load is reduced. allow it to be smaller.

However, each of the point A1 on the right front facing portion ST1 and the point A2 on the right front transmission portion 201 for defining the right front straight line LA is not limited to the above position points. The point A1 may be another point included in the right front facing portion ST1 capable of receiving the front load from the front side surface SF of the front axle 11, and the point A2 transmits the front load to the right frame main body 20R. Other points included in the right front transmission portion 201 that can be used may also be used. Specifically, for example, the right front straight line LA may be a straight line that passes through the rightmost point of the right front facing portion ST1 and the frontmost point of the right front transmission portion 201 in plan view shown in FIG. good.

Further, the right front load transmission portion 21R has a right front continuous portion CX that continues from the right front facing portion ST1 to the right front transmission portion 201 along the right front straight line LA in plan view shown in FIG. In this way, the right front continuous portion CX continues from the right front facing portion ST1 to the right front transmission portion 201 without a break in plan view. 201 continuously and efficiently. Specifically, the right front continuous portion CX continues from the right front facing portion ST1 to the right front transmission portion 201 while overlapping the right front straight line LA in plan view.

Note that the positional relationship between the right front load transmission 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 the other load transmission portions 22R, 21L, 22L described below.

In a plan view of the right rear load transmission portion 22R of the right crawler frame 2R, the right rear straight line LB, which is a straight line passing through a point B1 included in the right rear facing portion ST2 and a point B2 included in the right rear transmission portion 202, extends to the right. It has a shape to pass through the rear end roller 262 . The right rear straight line LB is a straight line that passes through the right rear end roller 262 and the turning center axis C in plan view. The right rear load transmission portion 22R is provided at a position overlapping the right rear straight line LB. In the present embodiment, the right rear straight line LB is positioned on the center axis of rotation of the right rear end roller 262 and at the center of the width direction (horizontal direction) of the right rear end roller 262 and the turning center axis C in plan view. is a straight line connecting

However, the point B1 on the right rear facing portion ST2 and the point B2 on the right rear transmission portion 202 for defining the right rear straight line LB are not limited to the above positions. The point B1 may be another point included in the right rear facing portion ST2 that can receive the rear load from the rear side surface SR of the rear axle 12, and the point B2 is the rear load on the right frame main body 20R. may be other points included in the right rear transmission portion 202 capable of transmitting the . Specifically, the right rear straight line LB is, for example, a straight line passing through the rightmost point of the right rear facing portion ST2 and the rearmost point of the right rear transmission portion 202 in plan view shown in FIG. There may be.

In this embodiment, the right rear load transmission portion 22R has a right rear continuous portion CX that continues from the right rear facing portion ST2 to the right rear transmission portion 202 along the right rear straight line LB in plan view. Specifically, the right rear continuous portion CX continues from the right rear facing portion ST2 to the right rear transmission portion 202 while overlapping the right rear straight line LB in plan view.

The effect obtained by providing the right rear load transmission portion 22R with the above configuration is the same as the effect described above for the right front load transmission portion 21R.

In the left front load transmission portion 21L of the left crawler frame 2L, in a plan view, a left front straight line LC, which is a straight line passing through a point C1 included in the left front facing portion ST3 and a point C2 included in the left front transmission portion 203, crosses the left front end roller 261. It has a shape that allows it to pass through. The left front straight line LC is a straight line that passes through the left front end roller 261 and the turning center axis C in plan view. The left front load transmission portion 21L is provided at a position overlapping the left front straight line LC. In the present embodiment, the left front straight line LC connects 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 and the turning center axis C in plan view. A straight line.

However, the point C1 on the front left facing portion ST3 and the point C2 on the front left transmission portion 203 for defining the front left straight line LC are not limited to the above positions. The point C1 may be another point included in the left front facing portion ST3 that can receive the front load from the front side surface SF of the front axle 11, and the point C2 transmits the front load to the left frame main body 20L. It may be other points included in the left front transmission part 203 where it is possible. Specifically, for example, the left front straight line LC may be a straight line that passes through the leftmost point of the left front facing portion ST3 and the frontmost point of the left front transmission portion 203 in plan view shown in FIG. good.

In the present embodiment, the left front load transmission portion 21L has a left front continuous portion CX that continues from the left front facing portion ST3 to the left front transmission portion 203 along the left front straight line LC in plan view. The left front continuous portion CX continues from the left front facing portion ST3 to the left front transmission portion 203 while overlapping the left front straight line LC in plan view.

The effect obtained by providing the left front load transmission portion 21L with the above configuration is the same as the effect described above for the right front load transmission portion 21R.

In a plan view of the left rear load transmission portion 22L of the left crawler frame 2L, the left rear straight line LD that is a straight line passing through the point D1 included in the left rear facing portion ST4 and the point D2 included in the left rear transmission portion 204 is on the left. It has a shape to pass through the rear end roller 262 . The left rear straight line LD is a straight line passing through the left rear end roller 262 and the turning center axis C in plan view. The left rear load transmission portion 22L is provided at a position overlapping the left rear straight line LD. In the present embodiment, the left rear straight line LD is positioned on the rotation center axis of the left rear end roller 262 and at the center of the left rear end roller 262 in the width direction (horizontal direction) and the turning center axis C in plan view. is a straight line connecting

However, the point D1 on the left rear facing portion ST4 and the point D2 on the left rear transmission portion 204 for defining the left rear straight line LD are not limited to the above positions. The point D1 may be another point included in the left rear facing portion ST4 capable of receiving a rear load from the rear side surface SR of the rear axle 12, and the point D2 may be a point where the rear load is applied to the left frame main body 20L. may be other points included in the left rear transmission portion 204 capable of transmitting the . Specifically, the left rear straight line LD is, for example, a straight line passing through the leftmost point of the left rear facing portion ST4 and the rearmost point of the left rear transmission portion 204 in plan view shown in FIG. There may be.

In this embodiment, the left rear load transmission portion 22L has a left rear continuous portion CX that continues from the left rear facing portion ST4 to the left rear transmission portion 204 along the left rear straight line LD in plan view. Specifically, the left rear continuous portion CX continues from the left rear facing portion ST4 to the left rear transmission portion 204 while overlapping the left rear straight line LD in plan view.

The effect obtained by providing the left rear load transmission portion 22L with the above configuration is the same as the effect described above for the right front load transmission portion 21R.

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

Similarly, the right rear transmission portion 202 of the right frame main body 20R is provided at a position where the front-rear direction position of the right rear transmission portion 202 and the front-rear position of the right rear end roller 262 overlap. Specifically, the rear end R2 of the right rear transmission portion 202 is located rearward of the rear end of the right rear end roller 262, and the front end F2 of the right rear transmission portion 202 is positioned further rearward than the rear end of the right rear end roller 262. is also located in the front. The positional relationship in the longitudinal direction between the front end F3 and rear end R3 of the left front transmission portion 203 and the front end and rear end of the left front end roller 261, and the front end F4 and rear end R4 of the left rear transmission portion 204 and the front end of the left rear end roller 262. And the positional relationship in the front-rear direction with the rear end is the same.

Further, as shown in FIG. 3, the left ends of the right front load transmission portion 21R and the right rear load transmission 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 transmission portion 21R receives the front side 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. The facing portion ST2 is configured to receive the rear side 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 front load is efficiently transmitted from the right front facing portion ST1 and the left front facing portion ST3 to the right front transmission portion 201 and the left front transmission portion 203 via portions near the right front straight line LA and the left front straight line LC, respectively. becomes possible.

Similarly, the right ends of the left front load transmission portion 21L and the left rear load transmission portion 22L of the left crawler frame 2L are positioned to the right of the right end of the left crawler belt 25L. Then, the left front facing portion ST3 of the left front load transmission portion 21L receives the front side 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. The facing portion ST4 is configured to receive the rear side 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 rear load is transferred from the right rear facing portion ST2 and the left rear facing portion ST4 to the right rear transmission portion 202 and the left rear transmission portion 204 via portions near the right rear straight line LB and the left rear straight line LD. It becomes possible to efficiently transmit to each other.

Further, as shown in FIG. 3, the left ends of the right front load transmission portion 21R and the right rear load transmission 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 transmission portion 21L and the left rear load transmission 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.

5 is a schematic cross-sectional view taken along line VV in FIG. 3, and FIG. 6 is an enlarged cross-sectional view of a portion surrounded by a dashed line VI in FIG. 5 and 6 are diagrams showing an example of a specific structure for transmitting the front side load from the front side surface SF of the front axle 11 to the left front facing portion ST3 of the left front load transmission portion 21L.

As shown in FIGS. 5 and 6, the front side surface SF and the left front facing portion ST3 for transmitting the front load are provided above the front axle 11 and the left front load transmission portion 21L, respectively.

In this embodiment, when the car body 10 does not receive the front load from the upper revolving body 102, as shown in FIG. are spaced apart in the fore-and-aft direction. On the other hand, when the car body 10 receives the front load from the upper revolving body 102, the lower frame 1 partially bends slightly forward, causing the front side surface SF of the front axle 11 and the left front facing portion of the left front load transmission portion 21L to move. The side surface of ST3 contacts. As a result, the front load is transmitted from the front side surface SF of the front axle 11 to the left front facing portion ST3 of the left front load transmission portion 21L. That is, the front load is transmitted from the front axle 11 to the left front load transmission portion 21L and further transmitted from the left front load transmission portion 21L to the left frame main body 20L due to metal contact between the front side surface SF and the side surface of the left front facing portion ST3. be.

Although illustration is omitted, the structure of the front side surface SF and the right front facing portion ST1 for transmitting the front side load, the structure of the rear side surface SR and the right rear facing portion ST2 for transmitting the rear side load, and the above-mentioned The structures of the rear side surface SR and the left rear facing portion ST4 for transmitting the rear load are the same as those shown in FIGS. That is, the right front facing portion ST1 and the left front facing portion ST3 are configured to be in contact with the front side surface SF of the front axle 11 when the car body 10 receives the front load. is configured to contact the rear side surface SR of the rear axle 12 when the car body 10 receives the rear side load.

Further, in the present embodiment, as shown in FIG. 3, each of the right front load transmission portion 21R and the left front load transmission portion 21L has a shape such that its length in the left-right direction decreases toward the front side in plan view. . Specifically, the front edge of the right front load transmission portion 21R has a shape extending obliquely rightward toward the right frame main body 20R, and the front edge of the left front load transmission 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 transmission portion 21R and the left front load transmission portion 21L while ensuring the function of transmitting the front load to the front side of each of the frame bodies 20R and 20L as much as possible. Similarly, each of the right rear load transmission portion 22R and the left rear load transmission 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 transmission 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 transmission 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 transmission portion 22R and the left rear load transmission portion 22L while ensuring the function of transmitting the rear load to the rear side of each of the frame bodies 20R and 20L as much as possible. can be suppressed.

In this embodiment, since the front right load transmission portion 21R and the front left load transmission portion 21L are provided, the paths through which the front load is transmitted from the front axle 11 to the right frame main body 20R and the left frame main body 20L are shown in plan view. can be brought close to or matched with the front right straight line LA and the front left straight line LC, respectively. Since the front load is transmitted straight to the right frame main body 20R and the left frame main body 20L in this manner, deformation of the lower traveling body 101, especially deformation of the front axle 11, is suppressed compared to the conventional art. The same applies to the right rear load transmission portion 22R and the left rear load transmission portion 22L.

In addition, the front load must be transmitted to the right frame body 20R and the left frame body 20L via the right front load transmission portion 21R and the left front load transmission portion 21L, respectively, because the car body 10 receives the front load from the upper revolving body 102. That is, when the suspended load is suspended on the upper revolving body 102 on the front side of the lower traveling body 101 . Therefore, the front side surface SF of the front axle 11, the side surface of the right front facing portion ST1, and the side surface of the left front facing portion ST3 are arranged in the longitudinal direction as described above when the car body 10 is not receiving a front load from the upper revolving body 102. They can be separated or in contact. For the same reason, the rear side surface SR of the rear axle 12, the side surface of the right rear facing portion ST2, and the side surface of the left rear facing portion ST4 do not correspond to each other when the car body 10 is not receiving a rear load from the upper revolving body 102. They may be spaced apart in the front-rear direction as shown in 6, or they may be in contact with each other.

Further, when the car body 10 receives a front load from the upper revolving body 102, the upper portion of the front axle 11 is more inclined than the lower portion of the front axle 11. It is easier to approach the front left facing portion ST3 of the . Therefore, in the present embodiment, each of the right front facing portion ST1 of the right front load transmitting portion 21R and the left front facing portion ST3 of the left front load transmitting portion 21L is located at a position opposed to the upper portion of the front axle 11 in the front-rear direction. rear-facing side). As a result, the front load is reliably transmitted from the front axle 11 to the right front facing portion ST1 of the right front load transmitting portion 21R and the left front facing portion ST3 of the left front load transmitting portion 21L. For the same reason, in the present embodiment, the right rear facing portion ST2 of the right rear load transmission portion 22R and the left rear facing portion ST4 of the left rear load transmission portion 22L are arranged in the longitudinal direction with respect to the upper portion of the rear axle 12. It has the side surfaces (surfaces facing the front side) at opposing positions.

Further, in the present embodiment, the right front load transmission portion 21R and the left front load transmission portion 21L are not connected to the front axle 11 by a connection member such as a connection pin as in the third embodiment described later. The right rear load transmission portion 22R and the left rear load transmission portion 22L are not connected to each other by the rear axle 12 and the connection member. This simplifies the structure and improves workability such as assembly work during manufacturing and disassembly and assembly work during transportation.

As shown in FIG. 6, the left front facing portion ST3 of the left front load transmitting portion 21L may be configured by a member different from the main body portion of the left front load transmitting portion 21L. , are connected to the main body by means of connection such as welding, bolts and nuts. The right front facing portion ST1 of the right front load transmitting portion 21R, the right rear facing portion ST2 of the right rear load transmitting portion 22R, and the left rear facing portion ST4 of the left rear load transmitting portion 22L may be configured similarly. In this way, each facing portion is composed of a member different from the main body portion, thereby adjusting (positioning) the relative positions of the front axle 11 and the front right facing portion ST1 and the front left facing portion ST3, and the rear axle 12 and the rear axle 12. Adjustment (positioning) of the relative position between the right rear facing portion ST2 and the left rear facing portion ST4 is facilitated. However, each opposing portion may not be composed of a member different from the main body portion, and may be composed of one member.

Further, in this embodiment, as shown in FIG. 2, the right front load transmission portion 21R includes a top plate, a bottom plate, and side plates connecting these in order to ensure the rigidity necessary to receive and transmit the front load. It has a box-shaped structure containing The same applies to the other load transmission portions 21L, 22R, 22L. However, each of these load transmission portions may be configured by a solid member.

FIG. 7 is a plan view showing the undercarriage 101 according to the second embodiment. FIG. 8 is a schematic cross-sectional view along line VIII-VIII of FIG. FIG. 9 is an enlarged cross-sectional view of a portion surrounded by a dashed line IX in FIG.

The undercarriage 101 according to the second embodiment is different from the above-described first embodiment in that it further includes a right front intervening member, a right rear intervening member, a left front intervening member, and a left rear intervening member, which will be described below. is the same as that of the first embodiment. Therefore, below, regarding the undercarriage 101 according to the second embodiment, mainly the configuration different from that of the first embodiment will be described.

As shown in FIGS. 7 to 9, the lower traveling body 101 according to the second embodiment further includes a right front intervening member 30, a right rear intervening member 30, a left front intervening member 30, and a left rear intervening member 30. As shown in FIGS. The right front intervening member 30 and the left front intervening member 30 each constitute a front intervening member, and the right rear intervening member 30 and the left rear intervening member 30 respectively constitute a rear intervening member.

The right front intervening member 30 is detachably arranged in a right front gap G1 formed between the front side surface SF of the front axle 11 and the right front facing portion ST1. The right front intervening member 30 is configured to contact both the front side surface SF and the right front facing portion ST1 when the car body 10 receives the front load. As a result, the front load is transmitted from the front axle 11 to the right front load transmission portion 21R by the metal contact between the front side surface SF and the right front intervening member 30 and the metal contact between the side surface of the right front facing portion ST1 and the right front intervening member 30. , and further transmitted from the right front load transmission portion 21R to the right frame main body 20R.

The right rear intervening member 30 is detachably arranged in a right rear gap G2 that is a gap formed between the rear side surface SR of the rear axle 12 and the right rear facing portion ST2. The right rear intervening member 30 is configured to contact both the rear side surface SR and the right rear facing portion ST2 when the car body 10 receives the rear load. As a result, the rear load is transferred from the rear axle 12 to the rear axle 12 by metal contact between the rear side surface SR and the right rear intervening member 30 and metal contact between the side surface of the right rear facing portion ST2 and the right rear intervening member 30. 22R, and further transmitted from the right rear load transmission portion 22R to the right frame main body 20R.

The left front intervening member 30 is detachably arranged in a left front gap G3 formed between the front side surface SF of the front axle 11 and the left front facing portion ST3. The left front intervening member 30 is configured to contact both the front side surface SF and the left front facing portion ST3 when the car body 10 receives the front load. As a result, the front load is transmitted from the front axle 11 to the left front load transmission portion 21L by the metal contact between the front side surface SF and the left front intervening member 30 and the metal contact between the side surface of the left front facing portion ST3 and the left front intervening member 30. , and further transmitted from the left front load transmission portion 21L to the left frame main body 20L.

The left rear intervening member 30 is detachably arranged in a left rear gap G4 that is a gap formed between the rear side surface SR of the rear axle 12 and the left rear facing portion ST4. The left rear intervening member 30 is configured to contact both the rear side surface SR and the left rear facing portion ST4 when the car body 10 receives the rear load. As a result, the rear load is transferred from the rear axle 12 to the left rear load by the metal contact between the rear side surface SR and the left rear intervening member 30 and the metal contact between the side surface of the left rear facing portion ST4 and the left rear intervening member 30. 22L, and further transmitted from the left rear load transmission portion 22L to the left frame main body 20L.

In this embodiment, as shown in FIGS. 8 and 9, each intervening member 30 includes a transmission plate 32 and a stopper 31 provided on the upper end of this transmission plate 32. As shown in FIG. The transmission plate 32 is, for example, a plate-like portion, and has a thickness (dimension in the front-rear direction) slightly smaller than the size of the corresponding gap so that it can be inserted into the corresponding gap. The stopper 31 has a longitudinal dimension larger than the size of the corresponding gap so that it cannot be inserted into the corresponding gap. Therefore, the transmission plate 32 of each intervening member 30 is inserted into the corresponding gap, and the lower surface of the stopper 31 is arranged to span between the upper surface of the front axle 11 or the rear axle 12 and the upper surface of the corresponding load transmission portion. , the intervening members 30 are restricted from moving downward.

In this embodiment, the horizontal position of each crawler frame 2R, 2L relative to the front axle 11 and the rear axle 12 can be adjusted more smoothly, and the front load can be transferred to the right front load transmission portion 21R and the left front load transmission portion 21L. and transmitting the rear load to the right rear load transmission portion 22R and the left rear load transmission portion 22L, respectively.

That is, in this aspect, a right front gap G1 and a left front gap G3 are respectively formed between the front side surface SF and the right front facing portion ST1 and the left front facing portion ST3, and the rear side surface SR and the right rear facing portion ST2 and left rear facing portion ST4 are formed. Since the right rear gap G2 and the left rear gap G4 are formed between the front Friction is less likely to occur between the side surfaces SF and the rear side surface SR and the facing portions ST1 to ST4. This enables smoother adjustment of the lateral positions of the crawler frames 2R and 2L.

On the other hand, when a load is lifted by the mobile crane 100, the intervening members 30 are arranged in the gaps G1 to G4, respectively. As a result, the front load can be transmitted from the front axle 11 to the right front load transmission portion 21R of the right crawler frame 2R and the left front load transmission portion 21L of the left crawler frame 2L via the right front intervening member 30 and the left front intervening member 30. , the rear load is transmitted from the rear axle 12 to the right rear load transmission portion 22R of the right crawler frame 2R and the left rear load transmission portion 22L of the left crawler frame 2L via the right rear intervening member 30 and the left rear intervening member 30. be able to.

FIG. 10 is a plan view showing the undercarriage 101 according to the third embodiment. 11 is a schematic cross-sectional view taken along line XI-XI of FIG. 10. FIG.

The lower running body 101 according to the third embodiment is different from the above-described first embodiment in that it further includes a right front connection pin, a right rear connection pin, a left front connection pin, and a left rear connection pin, which will be described below. is the same as that of the first embodiment. Therefore, the configuration of the undercarriage 101 according to the third embodiment, which is different from that of the first embodiment, will be mainly described below.

As shown in FIGS. 10 and 11, the undercarriage 101 according to the third embodiment further includes a right front connection pin P1, a right rear connection pin P2, a left front connection pin P3, and a left rear connection pin P4. The right front connection pin P1 and the left front connection pin P3 each constitute a front connection member, and the right rear connection pin P2 and the left rear connection pin P4 each constitute a rear connection member.

The right front connection pin P1 is detachably attached to the front axle 11 and the right front facing portion ST1 to connect them. The right rear connection pin P2 is detachably attached to the rear axle 12 and the right rear facing portion ST2 to connect them. The left front connection pin P3 is detachably attached to the front axle 11 and the left front facing portion ST3 to connect them. The left rear connection pin P4 is detachably attached to the rear axle 12 and the left rear facing portion ST4 to connect them.

As shown in FIG. 11, a left front facing portion ST3 of the left front load transmission portion 21L and a left rear facing portion ST4 of the left rear load transmission portion 22L of the left crawler frame 2L are provided with insertion holes H1. Of the front side portion including the front side surface SF and the rear side portion including the rear side surface SR of the rear axle 12, insertion holes H2 are provided at portions corresponding to the insertion holes H1. Although not shown, similar insertion holes H1 are provided in the right front facing portion ST1 and the right rear facing portion ST2, respectively. Similar through-holes H2 are also provided in portions of the side portion corresponding to these through-holes H1.

In this embodiment, as shown in FIG. 11, each connection pin includes a shaft and a stopper provided at one end of the shaft. The shaft portion is, for example, a columnar portion and has an outer diameter slightly smaller than the through holes H1 and H2 so that it can be inserted into the corresponding through holes H1 and H2. The stopper has, for example, an outer diameter larger than that of the insertion hole H1 so that it cannot be inserted into the insertion hole H1. A drop-off prevention member (not shown) is attached to the other end of each connection pin attached to the corresponding axle and facing portion, thereby preventing each connection pin from dropping out of the insertion holes H1 and H2.

In this embodiment, when the car body 10 receives the front load, the front load is transferred from the front side surface SF of the front axle 11 to the front right facing portion ST1 and the front left facing portion ST3 via the front right connecting pin P1 and the front left connecting pin P3. When the car body 10 receives the rear load, the rear load is transferred from the rear side surface SR of the rear axle 12 via the right rear connection pin P2 and the left rear connection pin P4 to the right rear facing portion ST2 and It is transmitted to the left rear facing portion ST4. As a result, the front load can be transmitted to the right front load transmission portion 21R and the left front load transmission portion 21L, respectively, and the rear load can be transmitted to the right rear load transmission portion 22R and the left rear load transmission portion 22L, respectively. be able to. On the other hand, the lateral positions of the right crawler frame 2R and the left crawler frame 2L can be changed with respect to the front axle 11 and the rear axle 12 by removing the connection pins P1 to P4.

Further, in this embodiment, the axial direction of each of the connection pins P1 to P4 is oriented in the front-rear direction. In this case, the connection pins P1 to P4 can effectively restrict lateral displacement of each crawler frame with respect to the front axle 11 and the rear axle 12 . Therefore, the connection pins P1 to P4 have the function of transmitting the front side load and the rear side load to the corresponding load transmission portions, respectively, and the front axle 11 when the mobile crane 100 is carrying out the work of lifting the suspended load. and a function of effectively restricting lateral displacement of each crawler frame with respect to the rear axle 12 .

In this embodiment, the right front load transmission portion 21R and the left front load transmission portion 21L are connected to the front axle 11 and the connection pins P1 and P3, and the right rear load transmission portion 22R and the left rear load transmission portion 22L are The rear axle 12 and the connection pins P2, P4 are connected to each other. Therefore, for example, when the car body 10 receives the front load, the front portion of the lower traveling body 101 such as the front axle 11 bends forward and downward, while the rear portion of the lower traveling body 101 such as the rear axle 12 bends. The part is deformed so that it bends upward. Therefore, as in the third embodiment, the connection pins P1 and P3 connect the front axle 11 and the load transmission portions 21R and 21L, and the connection pins P2 and P4 connect the rear axle 12 and the load transmission portions 22R and 22L. In this case, the bending of the front portion and the bending of the rear portion as described above are suppressed, and the bending of the lower traveling body 101 as a whole is more effectively suppressed.

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

(A) Regarding the structure in which the facing part receives the load from the axle In each of the first to third embodiments, the structure in which the right front facing part and the left front facing part receive the load from the front axle, and the right rear facing part and the right rear facing part from the rear axle. The structure in which the left rear facing portion receives the load is the same for all four locations, but it is not limited to such an aspect. As a structure in which the four facing parts receive the load from the axle, there is a structure in which the facing parts receive the load by directly contacting the front side surface or the rear side surface (first embodiment), and a structure in which the facing parts receive the load via an intervening member ( 2nd embodiment) and the structure in which the opposing portion receives the load via the connection pin (third embodiment) may be mixed. Further, as the structure in which the four facing portions receive the load from the axle, structures other than the structures according to the first to third embodiments may be included.

(B) Straight Lines LA to LD In the first to third embodiments, the right front straight line LA is on the rotation center axis of the right front end roller 261 and in the width direction (horizontal direction) of the right front end roller 261 in plan view. It is a straight line connecting the central position and the turning center axis C, and the right rear straight line LB, left front straight line LC, and left rear straight line LD are similarly defined, but are not limited to such a form. The front right straight line LA may be, for example, a straight line that connects the turning center axis C and any part of the right front end roller 261 that is selected in advance in a plan view. For example, any one of the above-described portions may be the rearmost and rightmost portion of the right front end roller 261 in plan view. Similarly, the right rear straight line LB may be a straight line that connects the rotation center axis C and any part of the right rear end roller 262 that is selected in plan view, and the left front straight line LC may be, for example, a straight line connecting the turning center axis C and any part of the left front end roller 261 that is selected in plan view, and the left rear straight line LD is, in plan view, A straight line connecting the turning center axis C and any part of the left rear end roller 262 selected in advance may be used.

The front right straight line LA may be, for example, a straight line extending from any part of the swivel bearing 13 to the front right roller 261, and the front left straight line LC may be, for example, a straight line extending from any part of the swivel bearing 13 to the front left roller 261. 261 may be a straight line. In these cases, any part of the swivel bearing 13 may be, for example, the front end of the swivel bearing (the part corresponding to the central position of the front axle 11). In the case of the right front straight line LA, any portion of the swivel bearing 13 may be, for example, any portion of the range between the front end and the right end (rightmost portion) of the swivel bearing 13. . Similarly, in the case of the left front straight line LC, any portion of the swivel bearing 13 may be, for example, any portion of the range between the front end and the left end (leftmost portion) of the swivel bearing 13. good.

Similarly, the right rear straight line LB may be, for example, a straight line directed from any part of the swivel bearing 13 to the right rear end roller 262, and the left rear straight line LD may be, for example, any part of the swivel bearing 13. to the left rear end roller 262 may be a straight line. In these cases, any part of the swivel bearing 13 may be, for example, the rear end of the swivel bearing (the part corresponding to the central position of the rear axle 12). Further, in the case of the right rear straight line LB, any portion of the swivel bearing 13 may be, for example, any portion of the swivel bearing 13 in the range between the rear end and the right end. Similarly, in the case of the left rear straight line LD, any portion of the swivel bearing 13 may be, for example, any portion of the swivel bearing 13 in the range between the rear end and the left end.

(C) The undercarriage according to the above embodiment includes an expansion/reduction mechanism capable of expanding or contracting the distance from the turning center axis of the crawler frame in the left-right direction, but the expansion/reduction mechanism can be omitted. In this case, the right front axle support part and the right rear axle support part respectively support the front axle and the rear axle so that the position of the right frame body with respect to the front axle and the rear axle in the left-right direction cannot be changed. The left front axle support portion and the left rear axle support portion support the front axle and the rear axle so that the position of the left frame main body in the left-right direction with respect to the front axle and the rear axle cannot be changed. support each.

(D) 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. When the expansion/contraction mechanism is omitted, the front side surface SF may be a curved surface facing the front, or a flat surface facing the front and inclined with respect to at least one of the left-right direction and the up-down direction. . Similarly, the rear side surface SR may be a curved surface facing the rear side, or may be a flat surface facing the rear side and inclined with respect to at least one of the horizontal direction and the vertical direction.

(E) Specifications of Crane Although the crane according to the embodiment shown in FIG. 1 does not include 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 12: Rear axle 20L: Left frame body 20R: Right frame body 21L: Left front load transmission part 21R: Right front load transmission part 22L: Left rear load transmission Portion 22R: Right rear load transmission portions 23L, 24L: Left wheels 23R, 24R: Right wheel 25L: Left crawler belt 25R: Right crawler belt 26: Right roller, left roller 261: Left front end roller, right front end roller 262: Right rear End roller, left rear end roller 27: right front axle support portion, left front axle support portion 28: right rear axle support portion, left rear axle support portion 100: mobile crane 101: lower traveling body 102: upper revolving body C: center of revolving Axis SF: front side of front axle SR: rear side of rear axle

Claims (18)

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 extending to the right and left sides from the carbody, the front axle having a front side surface facing forward;
a rear axle extending to the right and left from the car body behind the front axle and having a rear side surface facing rearward;
a right crawler frame including a right frame main body, a right front load transmission portion, and a right rear load transmission portion extending in the front-rear direction on the right side of the turning center axis;
a left crawler frame including a left frame main body extending in the longitudinal direction on the left side of the turning center axis, a left front load transmission portion, and a left rear load transmission portion;
the right frame main body has a right front axle support portion and a right rear axle support portion that support the front axle and the rear axle, respectively;
the left frame main body has a left front axle support portion and a left rear axle support portion that support the front axle and the rear axle, respectively;
The front right load transmission portion has a shape protruding leftward from a front right transmission portion, which is a portion of the right frame main body located in front of the front right axle support portion, and the front axle is located on the left side of the front right axle support portion. has a right front facing portion facing in the longitudinal direction on the front side surface of the carbody, and the load received by the car body from the upper revolving body when a load is suspended on the upper revolving body on the front side of the lower traveling body is configured to be able to transmit the front load from the right front facing portion to the right front transmission portion,
The right rear load transmission portion has a shape that protrudes leftward from a right rear transmission portion, which is a portion of the right frame main body that is rearward of the right rear axle support portion, and protrudes leftward from the right rear axle support portion. A right rear facing portion facing the rear side surface of the rear axle on the left side in the front-rear direction is provided, and the car body is positioned behind the lower traveling structure when a load is suspended on the upper revolving structure. The rear side load, which is the load received from the upper rotating body, can be transmitted from the right rear facing portion to the right rear transmission portion,
The left front load transmission portion has a shape that protrudes rightward from a left front transmission portion, which is a portion of the left frame main body on the front side of the left front axle support portion, and the front axle is located on the right side of the left front axle support portion. has a left front facing portion facing in the front-rear direction on the front side surface of the, and is configured to be able to transmit the front load from the left front facing portion to the left front transmission portion,
The left rear load transmission portion has a shape that protrudes rightward from a left rear transmission portion, which is a portion of the left frame main body that is on the rear side of the left rear axle support portion. On the right side, the rear side surface of the rear axle has a left rear facing portion that faces in the longitudinal direction, and the rear load can be transmitted from the left rear facing portion to the left rear transmission portion. mobile crane undercarriage. The mobile crane undercarriage according to claim 1,
The right front axle support portion and the right rear axle support portion support the front axle and the rear axle, respectively, so that the position of the right frame main body in the left-right direction with respect to the front axle and the rear axle can be changed. configured as
The left front axle support part and the left rear axle support part respectively support the front axle and the rear axle so that the position of the left frame main body in the left-right direction with respect to the front axle and the rear axle can be changed. A mobile crane undercarriage configured to. The mobile crane undercarriage according to claim 1 or 2,
At least one of the right front facing portion and the left front facing portion is configured to contact the front side surface of the front axle when the car body receives the front load. The mobile crane undercarriage according to any one of claims 1 to 3,
At least one of the right rear facing portion and the left rear facing portion is configured to contact the rear side surface of the rear axle when the car body receives the rear load. body. The mobile crane undercarriage according to any one of claims 1 to 4,
further comprising at least one front intervention member;
The at least one front intervening member is detachably arranged in a gap formed between at least one of the right front facing portion and the left front facing portion and the front side surface of the front axle, An undercarriage of a mobile crane configured to contact both the front side surface and the at least one opposing portion when the carbody receives the front side load. The mobile crane undercarriage according to any one of claims 1 to 5,
further comprising at least one rear intervening member;
The at least one rear intervening member is detachably attached to a gap formed between at least one of the right rear facing portion and the left rear facing portion and the rear side surface of the rear axle. a mobile crane undercarriage configured to contact both the rear side surface and the at least one opposing portion when the carbody receives the rear side load. The mobile crane undercarriage according to any one of claims 1 to 6,
further comprising at least one front connection member;
The at least one front connecting member is detachably attached to at least one of the right front facing portion and the left front facing portion, and the front axle, and is connected to the at least one facing portion and the front axle. a mobile crane undercarriage configured to connect a A mobile crane undercarriage according to claim 7,
The at least one front connecting member is configured by a connecting pin,
The undercarriage of a mobile crane, wherein the axial direction of the connecting pin is oriented in the front-rear direction. The mobile crane undercarriage according to any one of claims 1 to 8,
further comprising at least one rear connection member;
The at least one rear connecting member is detachably attached to at least one facing portion of the right rear facing portion and the left rear facing portion, and the rear axle. A mobile crane undercarriage configured to connect with a rear axle. A mobile crane undercarriage according to claim 9,
The at least one rear connection member is configured by a connection pin,
The undercarriage of a mobile crane, wherein the axial direction of the connecting pin is oriented in the front-rear direction. The mobile crane undercarriage according to any one of claims 1 to 10,
a pair of right wheels rotatably supported by the front and rear ends of the right frame main body;
a pair of left wheels rotatably supported by front and rear ends of the left frame main body;
a plurality of right rollers spaced apart in the front-rear direction between the pair of right wheels and rotatably supported on a lower portion of the right frame body, the right front end roller positioned most forward and the roller closest to the right wheel; a plurality of right rollers including a trailing right trailing roller;
a plurality of left rollers spaced apart in the front-rear direction between the pair of left wheels and rotatably supported on a lower portion of the left frame body, the left front end roller being the most forward and the left roller being the most a plurality of left rollers including a rear left trailing roller,
In the front right load transmission portion, the front right straight line that passes through any point included in the front right facing portion and any point included in the front right transmission portion in a plan view is the right front end roller or the right front end. It is configured to pass through the front side of the roller,
In the left front load transmission portion, the left front straight line passing through any point included in the left front facing portion and any point included in the left front transmission portion in a plan view is connected to the left front end roller or the left front end. A mobile crane undercarriage configured to pass in front of the rollers. A mobile crane undercarriage according to claim 11,
The front right straight line is a straight line passing through the front right roller in plan view, and the front left straight line is a straight line passing through the front left roller in plan view. A mobile crane undercarriage according to claim 12,
The right front straight line is a straight line further passing through the turning center axis in plan view, and the left front straight line is a straight line further passing through the turning center axis in plan view. The mobile crane undercarriage according to any one of claims 11 to 13,
The front right load transmission portion has a front right continuous portion that continues from the front right facing portion to the front right transmission portion along the front right straight line in plan view,
The left front load transmission portion has a left front continuous portion extending from the left front facing portion to the left front transmission portion along the left front straight line in plan view. The mobile crane undercarriage according to any one of claims 11 to 14,
In the right rear load transmission portion, the right rear straight line passing through any point included in the right rear facing portion and any point included in the right rear transmission portion in plan view is the right rear end. It is configured to pass behind the roller or the right rear end roller,
In the left rear load transmission portion, the left rear straight line passing through any point included in the left rear facing portion and any point included in the left rear transmission portion in a plan view is the left rear end. An undercarriage of a mobile crane configured to pass behind the roller or the left rear end roller. A mobile crane undercarriage according to claim 15,
The undercarriage of a mobile crane, wherein the right rear straight line is a straight line passing through the right rear end roller in plan view, and the left rear straight line is a straight line passing through the left rear end roller in plan view. A mobile crane undercarriage according to claim 16,
The right rear straight line is a straight line further passing through the turning center axis in plan view, and the left rear straight line is a straight line further passing through the turning center axis in plan view. The mobile crane undercarriage according to any one of claims 15 to 17,
The right rear load transmission portion has a right rear continuous portion that continues from the right rear facing portion to the right rear transmission portion along the right rear straight line in plan view,
The left rear load transmission portion has a left rear continuous portion extending from the left rear facing portion to the left rear transmission portion along the left rear straight line in plan view.

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