This application is a National Stage of International Patent Application No. PCT/EP2014/058395, filed Apr. 24, 2014, which claims priority to foreign Japanese Patent Application No. 2013-093234, filed Apr. 26, 2013, the content of which are incorporated herein by reference in their entirety.
The present invention relates to a revolving frame having a characteristic welded structure and a work machine including the revolving frame.
As illustrated in
On the other hand, a revolving frame in which a gap is formed between a center frame and a sponson beam for supporting a cab and the center frame and the sponson beam are not welded directly to prevent the influence of stress is proposed (for example, see Patent Document 1).
When this gap structure is applied to portions where the skirt beams 3 are connected to the center frame 2, since the skirt beams 3 are not directly connected to the center frame 2, it is not possible to transmit the load applied to the skirt beams 3 of a fuel tank, a hydraulic oil tank, and the like mounted on the skirt beams 3 to the center frame 2. Thus, it is not advantageous to the strength of the skirt beams 3.
With the foregoing in view, it is an object of the present invention to provide a revolving frame having a welded structure capable of reducing the influence of stress from the center frame on portions in which beams are welded to the center frame and securing load supporting strength of the beams and to provide a work machine including the revolving frame.
According to a first aspect of the invention, there is provided a revolving frame including: a center frame provided so that a longitudinal direction thereof extends in a horizontal direction from a supporting portion and a height thereof decreases gradually in the longitudinal direction from the supporting portion; and a revolving frame having a plurality of beams welded to side surfaces of the center frame so as to support the load of a mounted object, wherein a beam welded further toward a rear side than a center of an entire length in the longitudinal direction of the center frame includes: a pair of beam side plates which has a notch groove formed by notching an upper portion of a distal end portion near the side surface of the center frame and in which a lower portion of the distal end portion is welded to a region on a lower side than a center in a height direction of the side surface of the center frame by a vertical welding portion; a beam upper plate integrally provided between upper portions of these beam side plates; and a notch connection plate which is welded between the pair of beam side plates so as to extend from the beam upper plate to reach the side surface of the center frame along the notch grooves and in which a distal end is welded to an intermediate portion in a height direction of the side surface of the center frame by a horizontal welding portion.
According to a second aspect of the present invention, there is provided the revolving frame according to claim 1 further including a pair of notch holes formed between the pair of beam side plates and the notch connection plate at a position adjacent to a welding portion welded to the side surface of the center frame by notching the pair of beam side plates and the notch connection plate.
According to a third aspect of the present invention, there is provided a work machine including: a lower traveling structure; an upper revolving structure provided so as to revolve in relation to the lower traveling structure; and a working device provided on the upper revolving structure, wherein the upper revolving structure includes the revolving frame according to the first or second aspect, and the working device is attached to the center frame of the revolving frame.
According to the first aspect of the present invention, when the beams are welded to the side surface of the center frame of which the height decreases as it advances in the longitudinal direction from the supporting portion, the welding portion in the upper portion of the beam welded to the rear side than the center of the entire length in the longitudinal direction of the center frame approaches the upper portion of the center frame in the conventional art and is likely to be influenced by the stress generated in the upper portion of the center frame. However, the upper portions of the distal end portions of the pair of beam side plates approaching the side surface of the center frame are notched to form the pair of notch grooves, the notch connection plate is welded between the pair of beam side plates so as to extend from the beam upper plate formed integrally between the upper portions of the pair of beam side plates to reach the side surface of the center frame along the notch grooves, and the distal end of the notch connection plate is welded to the intermediate portion in the height direction of the side surface of the center frame by the horizontal welding portion. In this way, a structure in which the height of the beam welded to the rear side near the welding portion is lowered is obtained. With this structure, it is possible to secure a distance for reducing the stress between the upper portion of the center frame and the welding portion of the beam. It is possible to reduce the influence of the stress applied to the welding portion of the beam from the upper portion of the center frame. Moreover, it is possible to transmit the load applied to the beam to the center frame through the welding portions by welding the center frame and the beam at lowered portions. It is possible to secure the load supporting strength of the beam that supports the load of mounted objects.
According to the second aspect of the present invention, the stress acting on the welding portions of the pair of beam side plates and the notch connection plate welded to the side surface of the center frame can be distributed by the pair of notch holes formed by notching the portions near the welding portions. Thus, it is possible to relieve concentration of stress that results in the rupture of the welding portions.
According to the third aspect of the present invention, it is possible to provide a work machine having a strong frame structure capable of reducing the influence of the stress acting on the welding portions of the beam welded to the rear side than the center of the entire length in the longitudinal direction of the center frame from the working device provided on the upper revolving structure so as to revolve in relation to the lower traveling structure through the center frame with the aid of the notch groove and the notch connection plate of the beam and securing the load supporting strength of the beam that supports the load of mounted objects.
Hereinafter, the present invention will be described in detail based on an embodiment illustrated in
As illustrated in
The upper revolving structure 14 includes a revolving frame 21 illustrated in
As illustrated in
As illustrated in
The revolving frame 21 further includes cab mounting portions 27 for supporting the cab 16, engine mounting portions 28 for supporting the engine, a counter weight attachment portion 29 to which the counterweight 18 is attached, a peripheral skirt portion 30 provided at distal ends of the skirt beams 25 and 26, and the like.
In the working device 15, a boom 33 and boom cylinders 34 that rotate the boom 33 illustrated in
As illustrated in
That is, as illustrated in
A beam upper plate 44 is welded between and integrated with the upper portions of the pair of beam side plates 42. A notch connection plate 45 formed to extend in an L-shape from the beam upper plate 44 to the side surface 24a along the notch grooves 43 is continuously welded between the pair of beam side plates 42 similarly to the beam upper plate 44. The distal end of the notch connection plate 45 is welded to an intermediate portion in the height direction of the side surface 24a by a horizontal welding portion 46. Moreover, the bottom plate 24c and the beam side plates 42 are welded by a welding portion 47.
The pair of beam side plates 42, the beam upper plate 44, and the notch connection plate 45 may be formed integrally, for example, by incising and bending one structural steel of a C-shaped cross-section, cutting an unnecessary portion, and welding a resulting structure. Moreover, the notch groove 43 and the notch connection plate 45 may not always have an L-shape but may be notched or bent in a circular arc shape, for example.
As illustrated in
Next, the operation and effects of the illustrated embodiment will be described with reference to a stress distribution diagram of
In the stress distribution diagram illustrated in
Thus, when the pair of notch grooves 43 is provided so that the welding portion 46 of the skirt beam 26 is located in a region extending along an intermediate height of the side surface 24a, the notch connection plate 45 is provided so as to extend along these notch grooves 43 to reach the side surface 24a, and the distal end of the notch connection plate 45 is welded to an intermediate portion in the height direction of the side surface 24a, the welding portion 46 is hardly influenced by the stress generated in the center frame 23A.
In the skirt beam 26 on the rear side of the body in which the height of the upper surface 24b of the center frame 23A is close to the height of the beam upper surface, by employing such a two-stage beam structure that the height of the skirt beam 26 is lowered near the welding portion in order to prevent the influence of the stress from the center frame 23A on the welding portion 46 of the skirt beam 26, a stress-reducing distance is secured between the upper surface 24b of the center frame 23A and the welding portion 46 of the skirt beam 26. Moreover, since welding is performed to portions excluding high-stress portions, it is not necessary to add a reinforcing material, processing of a weld toe, and the like.
By welding the center frame 23A and the skirt beam 26 at portions where the influence of stress is lowered, it is possible to transmit the load of tanks and the like applied to the skirt beam 26 to the center frame 23A and to secure the load supporting strength of the skirt beam 26.
That is, when the skirt beam 26 is welded to portions of the center frame 23A excluding the high-stress portion while lowering the height at the welding portion of the skirt beam 26, the load acting on the skirt beam 26 can be transmitted to the center frame 23A.
Conventionally, the height of a portion of the skirt beam 26 welded to the center frame 23A required for transmitting the load of the skirt beam 26 to the center frame 23A is approximately 50% of the beam height (that is, the entire beam height). However, since the relation between the load applied to the skirt beam 26 and the position of the center frame 23A changes depending on a model or the like, the height required at the portion of the skirt beam 26 welded to the center frame 23A may be changed.
As described above, when the skirt beams 25 and 26 are welded to the side surfaces 24a of the center frame 23 of which the height decreases as it advances in the longitudinal direction from the supporting portion 22 or the vicinity of the supporting portion 22, the welding portion in the upper portion of the skirt beam 26 welded to the rear side than the center of the entire length in the longitudinal direction of the center frame 23 approaches the upper portion of the center frame 23 in the conventional art and is likely to be influenced by the stress generated in the upper portion of the center frame 23. However, the upper portions of the distal end portions of the pair of beam side plates 42 approaching the side surface 24a of the center frame 23 are notched to form the pair of notch grooves 43, the notch connection plate 45 is welded between the pair of beam side plates 42 so as to extend from the beam upper plate 44 formed integrally between the upper portions of the pair of beam side plates 42 to reach the side surfaces 24a along the notch grooves 43, and the distal end of the notch connection plate 45 is welded to the intermediate portion in the height direction of the side surface 24a of the center frame 23 by the horizontal welding portion 46. In this way, a structure in which the height of the skirt beam 26 welded to the rear side near the welding portion is lowered is obtained.
With this structure, it is possible to secure a distance for reducing the stress between the upper portion of the center frame 23 and the welding portion 46 of the skirt beam 26. It is possible to reduce the influence of the stress applied to the welding portion 46 of the skirt beam 26 from the upper portion of the center frame 23. Moreover, it is possible to transmit the load applied to the skirt beam 26 to the center frame 23 through the welding portions 41, 46, and 47 by welding the center frame 23 and the skirt beam 26 at lowered portions. It is possible to secure the load supporting strength of the skirt beam 26 that supports the load of mounted objects.
Moreover, the stress acting on the welding portions 41 and 46 of the pair of beam side plates 42 and the notch connection plate 45 welded to the side surface 24a of the center frame 23 can be distributed by the pair of notch holes 48 formed by notching the portions near the welding portions 41 and 46. Thus, it is possible to relieve concentration of stress that results in the rupture of the welding portions 41 and 46.
Further, it is possible to provide a work machine having a strong frame structure capable of reducing the influence of the stress acting on the welding portions 41 and 46 of the skirt beam 26 welded to the rear side than the center of the entire length in the longitudinal direction of the center frame 23 from the working device 15 provided on the upper revolving structure 14 so as to revolve in relation to the lower traveling structure 12 through the center frame 23 with the aid of the notch groove 43 and the notch connection plate 45 of the skirt beam 26 and securing the load supporting strength of the skirt beam 26 that supports the load of mounted objects.
In the above embodiment, although the structure of welding the skirt beam 26 to one center frame 23A has been described, the present invention can be equally applied to a structure of welding other beams to the other center frame 23B.
Further, the revolving frame 21 of the present invention is not limited to the hydraulic shovel but can be applied to a self-propelled or stationary crane or the like, for example.
The present invention can be useful to companies that manufacture revolving frames such as hydraulic shovels and cranes, and work machines.
11: Hydraulic shovel as work machine
12: Lower traveling structure
14: Upper revolving structure
15: Working device
21: Revolving frame
22: Supporting portion
23: Center frame
24
a: Side surface
26: Skirt beam as beam
41: Welding portion
42: Beam side plate
43: Notch groove
44: Beam upper plate
45: Notch connection plate
46: Welding portion
48: Notch hole
Number | Date | Country | Kind |
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2013-093234 | Apr 2013 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2014/058395 | 4/24/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2014/174042 | 10/30/2014 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
6098739 | Anderson | Aug 2000 | A |
6158525 | Inoue | Dec 2000 | A |
20080073938 | Lee | Mar 2008 | A1 |
20100290883 | Kitatani et al. | Nov 2010 | A1 |
Number | Date | Country |
---|---|---|
201 817 838 | May 2011 | CN |
07-150589 | Jun 1995 | JP |
H07 260689 | Jun 1995 | JP |
H10 37243 | Feb 1998 | JP |
2007 046374 | Feb 2007 | JP |
200 168 768 | Feb 2000 | KR |
2008 0093582 | Oct 2008 | KR |
WO-2005032996 | Apr 2005 | WO |
WO-2006033311 | Mar 2006 | WO |
Entry |
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International Search Report dated Jul. 7, 2014 from Application No. PCT/EP2014/058395. |
Number | Date | Country | |
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20160083929 A1 | Mar 2016 | US |