JP2010241586A - Revolving frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently prevent occurrence of buckling of side plates toward the outside in a thickness direction by reducing the magnitude of moment acting on the side plates and causing out-of-plane bending. <P>SOLUTION: A revolving frame include: a bottom plate 6 arranged on a revolving bearing 35; right and left side plates 2, 3 each oppositely arranged so as to separate from each other in a width direction D of the revolving frame 1 and having a front part fixed on the bottom plate 6; right and left boom connection sections 10 having front ends of the respective side plates 2, 3 and facing plates 10a arranged opposite to the front ends, and supporting a base end of a boom of a crane so as to be rotatable about a horizontal axis; and a reinforcing section provided so as to distribute a load applied to the boom connection sections 10 from the boom to a revolving bearing section 35 side. The reinforcing section includes reinforcing longitudinal plates 21 arranged so as to separate inside in the width direction D from the respective side plates 2, 3 and oppose to the side plates 2, 3 and having front ends connected to the facing plates 10a and lower ends joined on the bottom plate 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a turning frame provided in a crane.

  As a crane, there is known an LBCC (Like Beam Crawler Crane) having a lattice-structured boom and capable of self-propelling on an endless track (crawler). As shown in FIG. 8, the LBCC has a lower traveling body 101 provided with a crawler, and a turning frame 103 provided on the lower traveling body 101 so as to be turnable via a turning bearing 102. , A boom 104 that can be raised and lowered at a boom connecting portion 105 provided at the front portion of the swing frame 103, a cable 107 that is connected to a guy line fixing portion 106 that is disposed at the rear portion of the swing frame 103, And an unterweight 108 disposed at the rear.

  As a coupling configuration of the boom to the turning frame (boom connecting portion), a connecting portion having a pair of plate members is provided on each of the left and right sides of the boom base end portion, and one plate shape is provided on each of the left and right of the front upper portion of the turning frame. There is known a configuration in which three connected plate members are connected by a horizontal shaft while one connected plate member is provided between each pair of connected plate members. For example, refer nonpatent literature 1 etc.). Alternatively, conversely to this configuration, as shown in FIG. 9, to-be-connected parts (corresponding to the boom connecting part 105) 110 having a pair of plate members 110a are provided on the left and right of the upper part of the front side of the revolving frame 103. The connection part 120 which has one plate-like 120a is provided in each of the right and left of the base end part, and one plate-like 120a which is each connection part 120 is put between a pair of plate members 110a which are the connected parts 110, respectively. A configuration in which three plate members 110a, 120a, 120a are connected by a horizontal shaft 130 is also known. 9, one of the pair of plate members 110a is the side plate 111 of the swivel frame 103, and the other is the counter plate 112 disposed to face the inside of the side plate 111. The opposing plate 112 is connected to the side plate 111 via a connecting piece 113. In FIG. 9, the slewing bearing 102 is indicated by a two-dot chain line.

KOBELCO mastertech 7050 Crawler Crane Luffing Tower Catalog p3-4 Front view of crane

  By the way, even in a general crane as well as a crane having the above-described combined configuration, when a suspended load is lifted by a boom, a pivot axial force A is applied to a swing frame 103 from a boom connecting portion 105 as shown in FIG. Acts on the rear lower direction of the swivel frame 103, while the tension (the force for pulling the boom 104 from the rear) B from the guy line fixing unit 106 at the rear part of the swivel frame 103 is applied to the front of the swivel frame 103. Acts in the direction. Due to the horizontal components A1 and B1 of the boom axial force A and the cable tension B, the swing frame 103 is subjected to a compressive load from the front-rear direction, whereby the swing frame 103 is entirely in the front-rear direction (longitudinal direction). Curve (shown with a broken line). In particular, when the suspended load is lifted from the ground, the horizontal components A1 and B1 of the boom axial force and the cable tension are remarkably increased, which may cause the left and right side plates 111 of the revolving frame 103 to buckle.

  In the revolving frame that receives a compressive load as described above, in the case of the coupling configuration as shown in FIG. 9, the input position of the boom axial force A to the boom connecting portion 105 is as shown in FIG. Since it is the opposing plate 112 and is offset closer to the center in the width direction D of the revolving frame 103 than the side plate 111, a moment F that causes out-of-plane bending is generated in the side plate portion 111a immediately after the boom connecting portion 105. To do. This moment F has a drawback that local buckling (indicated by a one-dot chain line in FIG. 11) occurs at an early stage such that the side plate 111a goes outward in the thickness direction (width direction D).

  Therefore, as a means for preventing the occurrence of buckling toward the outside in the thickness direction of the side plate, increasing the plate thickness of the side plate or providing a reinforcing rib on the side plate is performed.

  However, since such a means mainly reinforces the side plate itself, in order to prevent the occurrence of buckling toward the outside in the thickness direction of the side plate, the thickness of the side plate is remarkably increased. Or a large number of reinforcing ribs need to be installed, which increases the cost and is not efficient.

  The present invention has been made to solve such problems of the prior art, and reduces the magnitude of the moment that causes out-of-plane bending that acts on the side plate, so that the seat toward the outside in the plate thickness direction of the side plate is provided. An object of the present invention is to provide a swivel frame that can efficiently prevent the occurrence of bending.

  A turning frame according to claim 1 of the present invention is a turning frame that is provided on a crane and is mounted on a lower traveling body of the crane so as to be turnable via a turning bearing, and is disposed on the turning bearing. From the bottom plate, the left and right side plates that are disposed to be spaced apart from each other in the width direction of the revolving frame, and at least the front portion is fixed on the bottom plate, the front end portions of the side plates, and the front end portions Left and right boom connecting portions that support the base end portion of the boom of the crane so as to be rotatable about a horizontal axis, and a counter plate disposed to face the front end portion at a position spaced inward in the width direction; A reinforcing portion provided to disperse a load applied to the boom connecting portion from the boom to the swing bearing side, and the reinforcing portion is spaced apart from each side plate inward in the width direction. Are arranged so as to face the lower end portion with its front end is connected to the opposite plate, characterized in that it comprises a reinforcing longitudinal plate which is bonded onto the bottom plate.

  The revolving frame according to claim 2 of the present invention is the revolving frame according to claim 1, wherein the reinforcing portion is further provided so as to connect the upper side portion of the reinforcing vertical plate and the side plate. The reinforcing top plate is included.

  The revolving frame according to claim 3 of the present invention is the revolving frame according to claim 2, wherein the reinforcing portion is further disposed between the opposing plate and the reinforcing vertical plate in the width direction of the crane. A reinforcing front plate, and the reinforcing front plate includes a rear side portion of the opposing plate, the reinforcing vertical plate, an inner surface of the side plate, a front end of the reinforcing top plate, and an upper surface of the bottom plate. It is characterized by being joined to each.

  The revolving frame according to claim 4 of the present invention is the revolving frame according to claim 2 or 3, wherein the reinforcing portion further includes a rear reinforcing body disposed on the rear side of the reinforcing vertical plate, The rear reinforcing body is joined to a rear side portion of the reinforcing vertical plate, an inner side surface of the side plate, a rear end of the reinforcing top plate, and an upper surface of the bottom plate, respectively.

  The revolving frame according to claim 5 of the present invention is the revolving frame according to claim 4, wherein the rear reinforcing body extends in the width direction of the crane and is arranged so as to connect them between the left and right side plates. It is characterized by that.

  The swing frame according to a sixth aspect of the present invention is the swing frame according to the fifth aspect, wherein the rear reinforcing member is disposed so as to pass above the swing bearing.

  The revolving frame which concerns on Claim 7 of this invention is a revolving frame of Claim 5 or 6, The said back side reinforcement body has a shape which comprises a closed cross section with the said baseplate, It is characterized by the above-mentioned.

  The swivel frame according to claim 8 of the present invention is the swivel frame according to any one of claims 1 to 7, wherein the reinforcing vertical plate is disposed so as to pass above the swivel bearing. To do.

  The revolving frame according to claim 9 of the present invention is characterized in that, in the revolving frame according to claim 8, the reinforcing vertical plate has a shape such that its upper end becomes lower toward the rear.

  In the present invention, the reinforcing vertical plate is provided on the inner side in the width direction than the side plate of the swivel frame so as to be opposed to the side plate and connected to the opposing plate and the bottom plate constituting the boom connecting portion. Transmits axial force from the boom acting on the boom connecting part from the opposing plate constituting the boom connecting part to the bottom plate by the reinforcing vertical plate, and further to a strong slewing bearing disposed below the bottom plate. Can do. That is, the axial force can be distributed to the side plate and the reinforcing vertical plate spaced inward from the side plate. As a result, the magnitude of the moment acting on the side plate of the swivel frame and causing out-of-plane bending can be reduced, and the occurrence of buckling toward the outer side in the plate thickness direction of the side plate can be efficiently prevented.

  In the invention according to claim 2, since the reinforcing top plate is connected to the upper side portion and the side plate of the reinforcing vertical plate, the axial force from the boom acting on the boom connecting portion is reduced. , It is possible to transmit to the reinforcing vertical plate via the reinforcing top plate and transmit it to the slewing bearing, which also reduces the magnitude of the moment acting on the side plate and causing out-of-plane bending. it can.

  Further, in the case of the invention according to claim 3, since the reinforcing front plate is connected to the rear side portion of the opposing plate, the reinforcing vertical plate, the side plate, the reinforcing top plate, and the bottom plate, It is possible to transmit the axial force from the boom acting on the slewing bearing to the reinforcing vertical plate and the reinforcing top plate via the reinforcing front plate and transmit it to the slewing bearing, which also acts on the side plate, It is possible to further reduce the magnitude of the moment that generates.

  Further, in the case of the invention according to claim 4, since the rear reinforcing body is connected to the rear side portion of the reinforcing vertical plate, the side plate, the reinforcing top plate, and the bottom plate, it acts on the boom connecting portion. Can transmit the axial force from the boom to the revolving vertical plate, the reinforcing top plate and the bottom plate via the rear side reinforcing body and transmit it to the swivel bearing, which also acts on the side plate, It is possible to further reduce the magnitude of the moment that generates. In particular, when the rear reinforcement is connected to both side plates as in claim 5, the rigidity in the vicinity of the rear reinforcement of the swivel frame can be improved.

  Furthermore, in the case of the invention according to claim 6, since the rear reinforcing body is disposed on the bottom plate so as to pass above the swing bearing, the axial force from the boom acting on the boom connecting portion is The rear reinforcement connected to the reinforcing vertical plate can be transmitted to the high-strength slewing bearing in a concentrated manner, and this also reduces the magnitude of the moment acting on the side plate and causing out-of-plane bending. be able to. Here, the term “passing” includes not only a part of the rear reinforcing body passing above the slewing bearing but also crossing the slewing bearing from the outside to the inside or from the inside to the outside. In addition, when the rear side reinforcing body has a closed cross section as in claim 7, the strength of the rear side reinforcing body is remarkably increased, and the connection state between the rear side reinforcing body, the side plate, and the reinforcing vertical plate is determined. This makes it possible to further strengthen the moment acting on the side plate and causing the out-of-plane bending.

  Furthermore, in the case of the invention according to claim 8, since the reinforcing vertical plate is disposed on the bottom plate so as to pass above the swivel bearing, the axial force from the boom acting on the boom connecting portion is The reinforcing vertical plate can intensively transmit to the high-strength slewing bearing, and this also makes it possible to further reduce the magnitude of the moment acting on the side plate and causing out-of-plane bending. Here, the passing includes not only that a part of the reinforcing vertical plate passes above the slewing bearing but also crossing the slewing bearing from the outside to the inside or from the inside to the outside.

  Furthermore, in the case of the invention according to claim 9, in response to the change in the magnitude that the axial force from the boom that has acted on the boom connecting portion is transmitted from the front side to the rear side of the bottom plate, Since the height changes from the front side to the rear side, the weight increase is suppressed and the axial force from the boom is transmitted to the bottom plate compared to the case where the reinforcing vertical plate is formed with a constant height. Can be achieved at the same level.

It is the external appearance perspective view (partially broken and shown) which looked at the turning frame which concerns on one Embodiment of this invention from the right front side. It is the external appearance perspective view (partially broken and shown) which looked at the turning frame from the left front side. It is a top view which shows the turning frame. It is explanatory drawing of the fixed state of a baseplate and a turning bearing. It is a figure for demonstrating transmitting the axial force from the boom which acts on a boom connection part to a baseplate. It is a figure for demonstrating transmitting the axial force from the boom which acts on a boom connection part to a baseplate. It is a perspective view which shows the structure of the comparative example which provided the reinforcing rib in the side plate compared with this embodiment. It is a right view which shows an example of the crane to which this invention is applied. It is a perspective view explaining the structure of the conventional turning frame. It is explanatory drawing when a turning frame curves in the front-back direction. It is explanatory drawing which raise | generates buckling deformation | transformation of the side plate of a turning frame.

  The present invention will be specifically described below.

  FIG. 1 is an external perspective view (partially crushed) of a revolving frame according to an embodiment of the present invention, and FIG. 2 is an external perspective view (partially crushed) of the revolving frame viewed from the left front side. FIG. 3 is a plan view showing the turning frame. In addition, the crane applied by this embodiment is using the thing of the same structure as the crane shown in FIG. 8 except a turning frame, and abbreviate | omits description about the structure.

  As in the prior art, the swivel frame 1 includes left and right side plates 2 and 3 arranged at a predetermined interval in the width direction D, a front connecting plate 4 that connects the front ends of the side plates 2 and 3, and side plates 2 and 3. Of the rear connecting plate 5 that connects the rear ends of each other, the bottom plate 6, the upper flange 7, the lower flange 8, the left boom connecting portion 10 provided at the front end of the left side plate 2, and the right side plate 3. A right boom connecting portion 11 provided at the front end and a pair of guy line fixing portions 12 provided on the left and right sides of the rear portion 7a of the rear connecting plate 5 of the upper flange 7 are provided.

  The upper flange 7 is provided along the upper ends of the side plates 2 and 3 and the rear connecting plate 5 and protruding outward from the upper ends. The bottom plate 6 is provided in a range E from the front end of the revolving frame 1 to the middle of the rear side, and the front side portion of the left side plate 2 is fixed to the inner side in the width direction D than the left end 6a of the bottom plate 6. The front side portion of the right side plate 3 is fixed to the inner side in the width direction D than the right end 6 b of 6.

  The lower flange 8 is connected to the rear side of the bottom plate 6 and is provided along the lower ends of the side plates 2 and 3 and protruding outward from the lower ends. In the illustrated example, the bottom plate 6 is provided in the range E on the front side of the revolving frame 1 (see FIG. 3), but may be provided over the entire area in the front-rear direction of the revolving frame 1.

  The left boom connecting portion 10 is between the left side plate 2, a counter plate 10 a provided to face the front end of the side plate 2 inside the width direction D, and the side plate 2 and the counter plate 10 a. The ceiling plate 10b provided at the upper end position of the front connecting plate 4 and the connecting piece 10c provided between the rear side portion 10a-1 of the opposing plate 10a and the side plate 2 are provided. The part below the ceiling board 10b of the boom connection part 10 becomes the structure enclosed by the side board 2, the opposing board 10a, the front connection board 4, the connection piece 10c, the bottom board 6, and the ceiling board 10b in the airtight form. Yes. And each upper part of the side plate 2 and the opposing board 10a protrudes above this sealing structure part 10d, and the shaft attachment hole 10f is provided in each protrusion part. These shaft mounting holes 10f are holes that support the left foot portion (base end portion) of the boom so as to be swingable on a horizontal shaft.

  One boom connecting portion 11 on the right side is similarly configured. That is, the right boom connecting portion 11 includes a right side plate 3, a counter plate 11a provided on the inner side in the width direction D so as to face the front end of the side plate 3, and the side plate 3 and the counter plate 11a. And it has the ceiling board 11b provided in the upper end position of the front connection board 4, and the connection piece 11c provided between the rear side part 11a-1 and the side board 3 of the opposing board 11a. The part below the ceiling plate 11b of the boom connecting portion 11 is configured to be enclosed in a sealed manner by the side plate 3, the opposing plate 11a, the front connecting plate 4, the connecting piece 11c, the bottom plate 6, and the ceiling plate 11b. Yes. And each upper part of the side plate 3 and the opposing board 11a protrudes above this sealing structure part 11d, and the shaft attachment hole 11f is provided in each protrusion part. These shaft attachment holes 11f are holes that support the right foot portion (base end portion) of the boom so as to be swingable on a horizontal shaft.

  Moreover, the revolving frame 1 includes side plate reinforcing portions 20 and 30 which are the main parts of the present invention. The side plate reinforcing portions 20 and 30 transmit the boom axial force A as a load input from the boom connecting portions 10 and 11 from the bottom plate 6 to the swing bearing 35, and the side plate reinforcing portion 20 includes the left boom. The side plate reinforcing portion 30 is provided on the rear side of the right boom connecting portion 11 and connected to the boom connecting portion 11 on the rear side of the connecting portion 10. ing.

  The left side plate reinforcing portion 20 is a reinforcing vertical plate 21 provided behind the opposing plate 10a and in the width direction D of the side plate 2 so as to be separated from the side plate 2 and opposed thereto. The rear top plate 22 provided along the upper side 21 a of the reinforcing vertical plate 21, the rear side portion 21 c of the reinforcing vertical plate 21, and the rear side portion 22 c of the reinforcing top plate 22. And a left end portion of the side reinforcing body 13.

  The front side part 21b of the reinforcing vertical plate 21 and the front side part 22b of the reinforcing top plate 22 are connected to the connecting piece 10c, and the rear side part 21c of the reinforcing vertical plate 21 and the rear side side of the reinforcing top plate 22 are connected. The portion 22 c is connected to the left end portion of the rear reinforcing body 13, and the lower side portion 21 d of the reinforcing vertical plate 21 is connected to the bottom plate 6. Further, both ends of the reinforcing top plate 22 in the width direction D are connected to the side plate 2 and the upper side portion 21 a of the reinforcing vertical plate 21. Therefore, the left side plate reinforcing portion 20 has a closed cross-sectional configuration surrounded by the side plate 2, the reinforcing vertical plate 21, the reinforcing top plate 22, the connecting piece 10 c, the rear reinforcing body 13, and the bottom plate 6. It has become. The connecting piece 10 c connected to the side plate reinforcing portion 20 functions as a reinforcing front plate of the side plate reinforcing portion 20. The reinforcing vertical plate 21 is formed with the front side being high and the rear side being low, and the upper end position of the front side is made to coincide with the upper end position of the connecting piece 10c, so that the upper end of the rear side of the reinforcing vertical plate 21 is higher. The position is made to coincide with the upper end position of the front side plate 13a. Further, the reinforcing vertical plate 21 may be configured such that the front side is raised stepwise and the rear side is lowered stepwise instead of the configuration in which the front side is continuously increased and the rear side is lowered.

  The right side plate reinforcing portion 30 is provided on the rear side of the opposing plate 11a and on the inner side in the width direction D of the side plate 3 so as to be separated from the side plate 3 and opposed thereto, The rear top plate 32 provided along the upper side portion 31a of the reinforcing vertical plate 31, the rear side portion 31c of the reinforcing vertical plate 31, and the rear side portion 32c of the reinforcing top plate 32. A right end portion of the side reinforcing body 13.

  The front side part 31b of the reinforcing vertical plate 31 and the front side part 32b of the reinforcing top plate 32 are connected to the connecting piece 11c, and the rear side part 31c of the reinforcing vertical plate 31 and the rear side side of the reinforcing top plate 32 are connected. The portion 32 c is connected to the right end portion of the rear reinforcing body 13, and the lower side portion 31 d of the reinforcing vertical plate 31 is connected to the bottom plate 6. Further, both ends of the reinforcing top plate 32 in the width direction D are connected to the side plate 3 and the upper side portion 31 a of the reinforcing vertical plate 31. Therefore, the right side plate reinforcing portion 30 has a closed cross-sectional configuration surrounded by the side plate 3, the reinforcing vertical plate 31, the reinforcing top plate 32, the connecting piece 11 c, the rear side reinforcing body 13, and the bottom plate 6. It has become. The connecting piece 11 c connected to the side plate reinforcing portion 30 functions as a reinforcing front plate of the side plate reinforcing portion 30. The reinforcing vertical plate 31 is formed such that the front side is higher and the rear side is lower, and the upper end position of the front side is made to coincide with the upper end position of the connecting piece 11c, so that the upper end of the rear side of the reinforcing vertical plate 31 is higher. The position is made to coincide with the upper end position of the front side plate 13a. Further, the reinforcing vertical plate 31 may be configured such that the front side is raised stepwise and the rear side is lowered stepwise instead of the configuration in which the front side is continuously increased and the rear side is lowered.

  The rear reinforcing body 13 includes a front side plate 13a erected along the width direction D on the bottom plate 6, a rear side plate 13b erected in parallel to the rear side of the front side plate 13a, and a front side. A ceiling plate 13c covering a portion sandwiched between the side plate 13a and the rear side plate 13b. Lower ends of the front side plate 13a and the rear side plate 13b are connected to the upper surface of the bottom plate 6, and both end portions in the width direction D of the front side plate 13a, the rear side plate 13b, and the ceiling plate 13c are connected to the side plates 2 and 3, respectively. It is connected. Accordingly, the rear reinforcing body 13 has a closed cross-sectional configuration in which the side plate 2, the side plate 3, the bottom plate 6, the front side plate 13a, the rear side plate 13b, and the ceiling plate 13c are enclosed in a sealed manner. Further, the left end portion of the front side plate 13 a is connected to a reinforcing vertical plate 21 and a reinforcing top plate 22 constituting the left side plate reinforcing portion 20, and the right end portion of the side plate 13 a constitutes the right side plate reinforcing portion 30. The reinforcing vertical plate 31 and the reinforcing top plate 32 are connected to each other. A rear end 6c of the bottom plate 6 is disposed in the vicinity of the lower position of the rear side plate 13b.

  As shown in FIG. 3, the side plate reinforcing portions 20 and 30 are arranged so that the reinforcing vertical plates 21 and 31 cross over the swivel bearing 35 arranged on the lower side of the bottom plate 6 at two locations. . The outer ring 35a of the slewing bearing 35 is partially fixed to the bottom plate 6 by fixing bolts 36 (see FIG. 4). Further, the rear reinforcing member 13 and the boom connecting portions 10 and 11 are also disposed so as to pass above the swing bearing 35. In FIG. 4, 35b is a bearing, 35c is an inner ring, and 37 is a lower traveling body side mounting plate to which the inner ring 35c is fixed by a fixing bolt 35d.

  Therefore, the revolving frame according to the present embodiment configured as described above has the following effects.

  (1) Even if the input position of the boom axial force in the left and right boom connecting portions 10 and 11 is offset inward from the side plates 2 and 3, the side plate reinforcing portion 20 is provided on the rear side of the boom connecting portions 10 and 11. 30 is provided, and the boom axial force A as a load input from each of the boom connecting portions 10 and 11 is transmitted to the bottom plate 6 by the reinforcing vertical plates 21 and 31 as shown in FIGS. It can be transmitted to the bearing 35. That is, the boom axial force A can be distributed to the side plates 2 and 3 and the reinforcing vertical plates 21 and 31 spaced inward from the side plates 2 and 3. As a result, the magnitude of the moment (F shown in FIG. 11) acting on the side plates 2 and 3 of the swivel frame 1 that causes out-of-plane bending can be reduced, and the side plates 2 and 3 are seated toward the outside in the thickness direction. It is possible to efficiently prevent the occurrence of bending.

  (2) Since the reinforcing vertical plates 21 and 31 are provided so as to cross over the swing bearing 35, the boom axial force A is transmitted to the high-strength swing bearing 35 by the reinforcing vertical plates 21 and 31. This makes it possible to further reduce the magnitude of the moment.

  (3) Since the reinforcing top plates 22 and 32 are provided in addition to the reinforcing vertical plates 21 and 31, the boom axial force A is supplied to the reinforcing vertical plates 21 and 31 via the reinforcing top plates 22 and 32. Can be transmitted to the slewing bearing 35, which can further reduce the magnitude of the moment acting on the side plates 2 and 3 of the slewing frame 1 and causing out-of-plane bending. 3 can be efficiently prevented from buckling toward the outside in the thickness direction. This effect is further increased by the configuration having the rear reinforcing body 13.

  (4) Since the rear side reinforcement body 13 is connected to the both side plates 2 and 3, the rigidity of the vicinity of the rear side reinforcement body 13 in the revolving frame 1 can be improved.

  (5) Since the rear reinforcing body 13 is disposed on the bottom plate 6 so as to pass above the swivel bearing 35, the axial force A from the boom acting on the boom connecting portions 10 and 11 is supplied to the reinforcing vertical plate. The rear reinforcement 13 connected to 21 and 31 can be transmitted to the high-strength slewing bearing 35 intensively, and this also causes the magnitude of the moment acting on the side plates 2 and 3 to cause out-of-plane bending. Can be further reduced.

  (6) Since the rear side reinforcing body 13 forms a closed cross section, the strength of the rear side reinforcing body 13 is remarkably increased, and the rear side reinforcing body 13, the side plates 2, 3 and the reinforcing vertical plates 21, 31 are The connected state can be strengthened, and this also makes it possible to further reduce the magnitude of the moment acting on the side plate and causing out-of-plane bending.

  (7) The height of the reinforcing vertical plates 21 and 31 is reduced from the front side to the rear side, and the axial force A from the boom that has acted on the boom connecting portions 10 and 11 is changed from the front side to the rear side of the bottom plate 6. Therefore, the increase in weight can be suppressed and transmission of the axial force A to the bottom plate 6 can be achieved at the same level as compared with the case where the reinforcing vertical plate is formed with a constant height. .

  Next, weight reduction and buckling evaluation in the turning frame of this embodiment will be described.

  In the swivel frame of this embodiment, the weight of the swivel frame can be reduced as compared with the case where reinforcing ribs are provided on the side plate as in the prior art. When the buckling evaluation is performed with the stress value of the maximum portion), the stress value can be reduced. As a comparative example in which the reinforcing ribs are provided, three vertically long reinforcing ribs 38a, 38b, and 38c as shown in FIG. The two reinforcing ribs 38d and 38e are arranged. In addition, as a back side reinforcement body, in the example of FIG. 7, back side reinforcement body 13 'which has a protrusion part in the front side in the both ends of the width direction D is used.

In contrast to such a comparative example, in the case of the present embodiment, the weight of the turning frame 1 can be reduced by 20 kg, and the stress value can be reduced from 37 kg / mm ² in the comparative example to 20 kg / mm ^2. Become.

  In the above-described embodiment, the side plate reinforcing portion 20 is closed by the side plate 2, the reinforcing vertical plate 21, the reinforcing top plate 22, the connecting piece 10 c, the rear reinforcing body 13, and the bottom plate 6. There is no configuration, and the side plate reinforcing portion 30 has a closed cross-sectional configuration in which the side plate 3, the reinforcing vertical plate 31, the reinforcing top plate 32, the connecting piece 11 c, the rear reinforcing body 13, and the bottom plate 6 are enclosed in a sealed manner. However, the present invention is not limited to this. For example, even when the reinforcing vertical plates 21 and 31 are provided so as to be connected to the opposing plates 10a and 11a in at least the boom connecting portions 10 and 11, the boom axial force is caused by the reinforcing vertical plates 21 and 31. Can be transmitted to the bottom plate 6. Thereby, the magnitude of the moment acting on the side plates 2 and 3 of the swivel frame 1 that causes out-of-plane bending can be reduced, and the occurrence of buckling of the side plates 2 and 3 toward the outside in the thickness direction can be efficiently prevented. It becomes possible. By forming at least one or more of the reinforcing top plates 22, 32, the connecting pieces 10c, 11c, and the rear reinforcing body 13 to the reinforcing vertical plates 21, 31, a seat It becomes possible to prevent the occurrence of bending more efficiently.

  Moreover, when the boom connection parts 10 and 11 are the structures which have the connection pieces 10c and 11c, of course, these connection pieces 10c and 11c can be used as a reinforcing front plate.

  Furthermore, in the above-described embodiment, the present invention is applied to the revolving frame in which the rear reinforcing body 13 is disposed. However, the present invention is not limited to this, and can be applied to a revolving frame in which the rear reinforcing body 13 is omitted. . In this case, since the front side plate 13a does not exist, a plate material corresponding to the front side plate 13a is separately provided as the rear reinforcing body.

DESCRIPTION OF SYMBOLS 1 Revolving frame 2, 3 Side plate 6 Bottom plate 10, 11 Boom connection part 10a, 11a Opposite plate 10c, 11c Connection piece (front plate for reinforcement)
13 Rear reinforcement bodies 21, 31 Vertical plates for reinforcement 22, 32

Claims (9)

A swing frame provided in a crane and mounted on a lower traveling body of the crane so as to be swingable via a swing bearing,
A bottom plate disposed on the slewing bearing;
Left and right side plates that are opposed to each other in the width direction of the swivel frame and at least a front portion is fixed on the bottom plate;
Each of the side plates has a front end portion and a counter plate disposed opposite to the front end portion at a position spaced inward in the width direction from the front end portion, and rotates the base end portion of the boom of the crane around a horizontal axis. Left and right boom joints that are movably supported;
A reinforcing portion provided to disperse the load applied to the boom connecting portion from the boom to the swing bearing side,
The reinforcing portion is disposed so as to be spaced apart from each side plate inward in the width direction so as to face the side plate, and has a front end connected to the opposing plate and a lower end joined to the bottom plate. A swivel frame comprising a vertical plate for use. The swivel frame according to claim 1.
The reinforcing frame further includes a reinforcing top plate that is provided between the upper side portion of the reinforcing vertical plate and the side plate so as to connect them. The swivel frame according to claim 2,
The reinforcing portion further includes a reinforcing front plate disposed between the opposing plate and the reinforcing vertical plate facing the width direction of the crane, and the reinforcing front plate is disposed behind the opposing plate. A revolving frame characterized by being joined to a side part, the reinforcing vertical plate, an inner surface of the side plate, a front end of the reinforcing top plate, and an upper surface of the bottom plate, respectively. The swivel frame according to claim 2 or 3,
The reinforcing portion further includes a rear reinforcing body disposed on the rear side of the reinforcing vertical plate, and the rear reinforcing body includes a rear side portion of the reinforcing vertical plate and an inner side surface of the side plate. And a revolving frame that is joined to a rear end of the reinforcing top plate and an upper surface of the bottom plate. The swivel frame according to claim 4,
The rear reinforcing body extends in the width direction of the crane, and is disposed so as to connect the left and right side plates to each other. The swivel frame according to claim 5,
The swivel frame is characterized in that the rear reinforcing body is disposed so as to pass above the swivel bearing. The swivel frame according to claim 5 or 6,
The rear reinforcing body has a shape that forms a closed cross-section together with the bottom plate. In the turning frame according to any one of claims 1 to 7,
The swivel frame, wherein the reinforcing vertical plate is disposed so as to pass above the swivel bearing. The swivel frame according to claim 8,
The revolving vertical plate has a shape in which an upper end thereof becomes lower as it goes rearward.

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