U.S. patent application number 16/086068 was filed with the patent office on 2020-09-17 for box-shaped structure for work machine.
The applicant listed for this patent is KOMATSU LTD.. Invention is credited to Satoru KUBOTA, Yuki NAKATANI, Kenji SANADA, Kouji SHINKAWA, Nobuyasu SUGIHARA, Kazuo TAKAHASHI, Tooru TSUJI, Shinpei UTOU, Shuhei WATANABE.
Application Number | 20200291600 16/086068 |
Document ID | / |
Family ID | 1000004871106 |
Filed Date | 2020-09-17 |
![](/patent/app/20200291600/US20200291600A1-20200917-D00000.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00001.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00002.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00003.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00004.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00005.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00006.png)
![](/patent/app/20200291600/US20200291600A1-20200917-D00007.png)
United States Patent
Application |
20200291600 |
Kind Code |
A1 |
SUGIHARA; Nobuyasu ; et
al. |
September 17, 2020 |
BOX-SHAPED STRUCTURE FOR WORK MACHINE
Abstract
A boom includes a body and a base end bracket. The body includes
a straight section and a wide section. When viewed from above, a
width of the straight section is substantially constant. When
viewed from above, a width of the wide section increases toward the
base end bracket. The straight section and the wide section are
smoothly continuous to each other.
Inventors: |
SUGIHARA; Nobuyasu;
(Minato-ku, Tokyo, JP) ; NAKATANI; Yuki;
(Minato-ku, Tokyo, JP) ; UTOU; Shinpei;
(Minato-ku, Tokyo, JP) ; SHINKAWA; Kouji;
(Minato-ku, Tokyo, JP) ; KUBOTA; Satoru;
(Minato-ku, Tokyo, JP) ; WATANABE; Shuhei;
(Minato-ku, Tokyo, JP) ; TSUJI; Tooru; (Minato-ku,
Tokyo, JP) ; TAKAHASHI; Kazuo; (Minato-ku, Tokyo,
JP) ; SANADA; Kenji; (Minato-ku, Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOMATSU LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000004871106 |
Appl. No.: |
16/086068 |
Filed: |
September 28, 2017 |
PCT Filed: |
September 28, 2017 |
PCT NO: |
PCT/JP2017/035316 |
371 Date: |
September 18, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E02F 3/422 20130101;
E02F 3/382 20130101 |
International
Class: |
E02F 3/38 20060101
E02F003/38 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2016 |
JP |
2016-193969 |
Claims
1. A box-shaped structure for a work machine, comprising: a body
extending in a longitudinal direction; and a bracket connected to
one end of the body, the body including a straight section and a
wide section, the straight section having a substantially constant
width when viewed from above, and the wide section being connected
to the bracket and having a width that increases toward the bracket
when viewed from above, and the straight section and the wide
section being smoothly continuous to each other.
2. The box-shaped structure for a work machine according to claim
1, wherein the body is formed of a top plate, a bottom plate, a
first side plate and a second side plate; the bracket includes a
first abutment surface that abuts against the first side plate and
a second abutment surface that abuts against the second side plate;
and each of the first abutment surface and the second abutment
surface is angled with respect to the longitudinal direction of the
body.
3. The box-shaped structure for a work machine according to claim
1, wherein the body has a center boss centrally located in the
longitudinal direction; the bracket has an end boss; the straight
section is smoothly continuous to the wide section at a
predetermined position between the center boss and the end boss;
and a ratio of a first interval between a center axis of the center
boss and the predetermined position to a second interval between a
center axis of the end boss and the predetermined position is from
1:1 to 4:1.
4. A method of manufacturing a box-shaped structure for a work
machine, comprising: placing a first side plate and a second side
plate on a bottom plate; pushing one end portion of the first side
plate and one end portion of the second side plate outward using a
lining; sandwiching and fixing a bracket between the one end
portion of the first side plate and the one end portion of the
second side plate; and fixing a top plate on top of the first side
plate and the second side plate.
5. The box-shaped structure for a work machine according to claim
2, wherein the body has a center boss centrally located in the
longitudinal direction; the bracket has an end boss; the straight
section is smoothly continuous to the wide section at a
predetermined position between the center boss and the end boss;
and a ratio of a first interval between a center axis of the center
boss and the predetermined position to a second interval between a
center axis of the end boss and the predetermined position is from
1:1 to 4:1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National stage application of
International Application No. PCT/JP2017/035316, filed on Sep. 28,
2017. This U.S. National stage application claims priority under 35
U.S.C. .sctn. 119(a) to Japanese Patent Application No.
2016-193969, filed in Japan on Sep. 30, 2016, the entire contents
of which are hereby incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to a box-shaped structure for
a work machine.
[0003] A work vehicle, such as a hydraulic excavator, includes a
work machine that has a box-shaped structure formed of, for
example, a boom and an arm. In Japanese Unexamined Patent
application publication No. H6-220880, there is proposed a method
of forming a box-shaped structure with two separate bodies welded
together along a neutral axis, and expanding the width of the
box-shaped structure at an end portion thereof. The method
disclosed in Japanese Unexamined Patent application publication No.
H6-220880 describes that it can reduce a cross-section of the
box-shaped structure along a longitudinal direction thereof to
provide a lighter structure, while also preventing a decrease in
strength of the end portion that is mounted to another
structure.
SUMMARY
[0004] In the box-shaped structure of Japanese Unexamined Patent
application publication No. H6-220880A, each side plate of the
box-shaped structure is bent at a plurality of positions in order
to increase the width at an end portion thereof. Because of this,
stress concentrates at the bent portions of each side plate. In
particular, in the box-shaped structure of Japanese Unexamined
Patent application publication No. H6-220880 that has been made
with a smaller cross-section, more stress is generated at the bent
portions of each side plate due to the bending of the box-shaped
structure.
[0005] The present invention has been made in light of the
above-described problem, and it is an object of the present
invention to provide a box-shaped structure for a work machine that
can have improved durability.
[0006] A box-shaped structure for a work machine according to a
first aspect of the present invention includes a body that extends
in a longitudinal direction and a bracket that is connected to one
end of the body. The body including a straight section having a
substantially constant width when viewed from above, and a wide
section that is connected to the bracket and has a width that
increases toward the bracket when viewed from above, and the
straight section and the wide section are smoothly continuous to
each other.
[0007] According to the box-shaped structure for a work machine
according to the first aspect of the present invention, the wide
section has a width that increases toward the bracket, and hence
the cross-sectional area of the body can be increased on the
bracket side. With this configuration, strength of the body can be
enhanced. In addition, because the straight section and the wide
section are smoothly continuous to each other, it is possible to
reduce locally concentrating stresses in the body.
[0008] A box-shaped structure for a work machine according to a
second aspect of the present invention is the box-shaped structure
for a work machine according to the first aspect, in which the body
is formed of a top plate, a bottom plate, a first side plate and a
second side plate. The bracket includes a first abutment surface
that abuts against the first side plate and a second abutment
surface that abuts against the second side plate, and each of the
first abutment surface and the second abutment surface are angled
with respect to the longitudinal direction of the body.
[0009] A box-shaped structure for a work machine according to a
third aspect of the present invention is the box-shaped structure
for a work machine according to the first or second aspect, in
which the body has a center boss centrally located in the
longitudinal direction, and the bracket has an end boss. The
straight section is smoothly continuous to the wide section at a
predetermined position between the center boss and the end boss. A
ratio of a first interval between a center axis of the center boss
and the predetermined position to a second interval between a
center axis of the end boss and the predetermined position is from
1:1 to 4:1.
[0010] A method of manufacturing a box-shaped structure for a work
machine according to a fourth aspect of the present invention
including the steps of: placing a first side plate and a second
side plate on a bottom plate; pushing one end portion of the first
side plate and one end portion of the second side plate outward
using a lining; sandwiching and fixing a bracket between the end
portions of the first side plate and the second side plate; and
fixing a top plate on the first side plate and the second side
plate.
[0011] According to the present invention, there can be provided a
box-shaped structure for a work machine that can have improved
durability.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a side view of a hydraulic excavator.
[0013] FIG. 2 is a side view of a boom of the hydraulic excavator
of FIG. 1.
[0014] FIG. 3 is a plan view of the boom of FIG. 2.
[0015] FIG. 4 is a cross-sectional view taken along the line A-A of
the boom in FIG. 2.
[0016] FIG. 5 is a partially expanded view of the boom of FIG.
4.
[0017] FIGS. 6A-6D are schematic diagrams illustrating a method of
manufacturing the boom.
[0018] FIG. 7 is a schematic diagram illustrating the method of
manufacturing the boom including a pressing tool and a lining
tool.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0019] Configuration of Hydraulic Excavator 1
[0020] FIG. 1 is a side view for illustrating a hydraulic excavator
1. Herein, "up," "down," "front," "rear," "left" and "right" are
directions from the point of view of an operator sitting in a
driver's seat.
[0021] The hydraulic excavator 1 includes a traveling body 10, a
turning body 11, a counterweight 12, an engine compartment 13, a
device compartment 14, a cab 15 and a work machine 16.
[0022] The traveling body 10 has a pair of track pads that are
rotatable independently of each other. The turning body 11 is
turnably disposed on the traveling body 10. The turning body 11
provides a vehicle body frame of the hydraulic excavator 1.
[0023] The counterweight 12 is disposed on a rear end portion of
the turning body 11. The engine compartment 13 is disposed on the
turning body 11. The engine compartment 13 is disposed on the
turning body 11 in front of the counterweight 12. The engine
compartment 13 houses an engine, an exhaust gas processing device
and other components. The device compartment 14 is disposed on the
turning body 11 in front of the engine compartment 13. The device
compartment 14 houses a hydraulic pump, a fuel tank, a working
fluid tank and other components. The cab 15 is disposed on the
turning body 11 in front of the device compartment 14. The cab 15
is provided with a driver's seat where an operator sits.
[0024] The work machine 16 is mounted in a vertically swingable
manner on the turning body 11 in front of the device compartment 14
and to the right of the cab 15. The work machine 16 includes a boom
17, an arm 18, a bucket 19, a pair of boom cylinders 20, an arm
cylinder 21 and a bucket cylinder 22. The boom 17 is an example of
the "box-shaped structure for a work machine."
[0025] A base end portion of the boom 17 is swingably mounted to
the turning body 11. A tip end portion of the boom 17 is swingably
mounted to a base end side bracket 18b. A base end portion of the
arm 18 is mounted to the base end side bracket 18b. The bucket 19
is swingably mounted to a bucket bracket 18a that is provided on a
tip end portion of the arm 18.
[0026] Both boom cylinders 20 drive the boom 17. The boom cylinders
20 are linked to the turning body 11 and a center boss CB of the
boom 17. The arm cylinder 21 drives the arm 18. The bucket cylinder
22 drives the bucket 19.
[0027] Configuration of Boom 17
[0028] A configuration of the boom 17 according to this embodiment
is described with reference to the figures. FIG. 2 is a side view
for illustrating the boom 17. FIG. 3 is a plan view for
illustrating the boom 17.
[0029] The boom 17 includes a body 30, a base end bracket 31 and an
arm bracket 32. The base end bracket 31 is an example of a
"bracket" in this embodiment.
[0030] The body 30 extends in a longitudinal direction. The body 30
has a boomerang-like shape when viewed from the side. The body 30
is a hollow tube. The body 30 forms a box shape with a top plate
33, a bottom plate 34, a first side plate 35 and a second side
plate 36.
[0031] The first side plate 35 and the second side plate 36 are
disposed with a predetermined clearance therebetween. A rear end
portion of the first side plate 35 is deformed so as to expand
outward. Similarly, a rear end portion of the second side plate 36
is deformed so as to expand outward. A center boss CB that extends
in a width direction is attached to the first side plate 35 and the
second side plate 36. The center boss CB is located substantially
at the center of the body 30.
[0032] The top plate 33 is disposed so as to cover a top opening of
a space formed between the first side plate 35 and the second side
plate 36. The bottom plate 34 is disposed so as to cover a bottom
opening of the space formed between the first side plate 35 and the
second side plate 36.
[0033] The base end bracket 31 is connected to a rear end of the
body 30. The base end bracket 31 is provided with an end boss EB
that extends in the width direction. The base end bracket 31 may be
an ingot that is formed by casting a metal material.
[0034] The arm bracket 32 is connected to a front end of the body
30. The arm bracket 32 is provided with an arm mounting hole 32a.
The arm 18 (see FIG. 1) is mounted in the arm mounting hole 32a.
The arm bracket 32 may be an ingot that is formed by casting a
metal material.
[0035] Configuration of Body 30
[0036] A configuration of the body 30 is described with reference
to FIGS. 2 and 3.
[0037] The body 30 includes a straight section 30a and a wide
section 30b. The straight section 30a is formed of front side
portions of each of the top plate 33, the bottom plate 34, the
first side plate 35 and the second side plate 36. The wide section
30b is formed of rear side portions of each of the top plate 33,
the bottom plate 34, the first side plate 35 and the second side
plate 36.
[0038] The straight section 30a is continuous to the wide section
30b at a predetermined position LP between the center boss CB and
the end boss EB. The straight section 30a is smoothly continuous to
the wide section 30b at the predetermined position LP. In this
embodiment, "smoothly continuous" means that there is no point of
inflection in any of the top plate 33, the bottom plate 34, the
first side plate 35 and the second side plate 36 at the
predetermined position LP. None of the top plate 33, the bottom
plate 34, the first side plate 35 and the second side plate 36 are
bent at the predetermined position LP. Therefore, a drastic change
in the cross-sectional area of the body 30 at the predetermined
position LP is eliminated.
[0039] In this embodiment, as illustrated in FIG. 2, the
predetermined position LP at which the straight section 30a is
smoothly continuous to the wide section 30b is located
substantially center between the center boss CB and the end boss
EB. On an imaginary line that connects the center boss CB and the
end boss EB to each other, an interval L1 between a center axis AX1
of the center boss CB and the predetermined position LP is
substantially equal to an interval L2 between a center axis AX2 of
the end boss EB and the predetermined position LP. In this
embodiment, a ratio of the interval L1 to the interval L2 is
approximately 1:1. However, the predetermined position LP may be
anywhere as long as the wide section 30b does not interfere with
the pair of boom cylinders 20 (see FIG. 1). For example, the ratio
of the interval L1 to the interval L2 can be set between 1:1 to
4:1.
[0040] The straight section 30a is connected to the front of the
wide section 30b. As illustrated in FIG. 3, when viewed from above,
the straight section 30a has a width Wa of that is substantially
constant in the longitudinal direction. In this embodiment, the
width Wa of the straight section 30a is 450 mm.
[0041] The wide section 30b is connected to the rear of the
straight section 30a. As illustrated in FIG. 3, when viewed from
above, the wide section 30b has a width Wb that increases toward
the base end bracket 31. The width Wb of the wide section 30b is
not constant across the entire wide section 30b and continues to
increase from the predetermined position LP, at which the straight
section 30a and the wide section 30b are smoothly continuous to
each other, to the base end bracket 31. In this embodiment, the
width Wb of the wide section 30b has a maximum value of 570 mm. In
this embodiment, a ratio of the width Wa of the straight section
30a to the wide section 30b is 15:19.
[0042] As illustrated in FIG. 3, when viewed from above, a first
side surface S1 of the wide section 30b is convexly curved toward
the inner side of the body 30. Similarly, a second side surface S2
of the wide section 30b is convexly curved toward the inner side of
the body 30. The first side surface S1 is a part of a surface of
the first side plate 35 and the second side surface S2 is a part of
a surface of the second side plate 36.
[0043] In this embodiment, the wide section 30b has a height that
becomes smaller toward the base end bracket 31 from the straight
section 30a. On the other hand, as described above, the width of
the wide section 30b increase from the predetermined position LP,
at which the straight section 30a and the wide section 30b are
smoothly continuous to each other, to the base end bracket 31. With
this configuration, the wide section 30b, which is most likely
subject to load, is able to have improved bending strength at the
sides.
[0044] Configuration of Base End Bracket 31
[0045] FIG. 4 is a cross-sectional view taken along the line A-A in
FIG. 2. FIG. 5 is a partially expanded view of FIG. 4.
[0046] The base end bracket 31 is formed in a shape that is
entirely tapered toward the body 30. The base end bracket 31
includes a first abutment surface S3, a second abutment surface S4,
and a front end surface S5.
[0047] The first side plate 35 of the body 30 abuts against the
first abutment surface S3. The first abutment surface S3 is formed
so as to be angled with respect to the longitudinal direction of
the body 30 such that the first abutment surface S3 follows the
first side plate 35 that expands outward. The first abutment
surface S3 is a part of a left side surface of the base end bracket
31.
[0048] The second side plate 36 of the body 30 abuts against the
second abutment surface S4. The second abutment surface S4 is
formed so as to be angled with respect to the longitudinal
direction of the body 30 such that the second abutment surface S4
follows the second side plate 36 that expands outward. The second
abutment surface S4 is a part of a right side surface of the base
end bracket 31.
[0049] The front end surface S5 is continued to the first abutment
surface S3 and the second abutment surface S4. In this embodiment,
the front end surface S5 is formed into a flat plate, but the front
end surface S5 is not limited to this shape.
[0050] Method of Manufacturing Boom 17
[0051] FIGS. 6A to 6E and FIG. 7 are schematic diagrams for showing
a method of manufacturing the boom 17.
[0052] First, as illustrated in FIG. 6A, the bottom plate 34 having
a rear end portion that flares toward the bottom is prepared.
[0053] Next, as illustrated in FIG. 6B, the first side plate 35 and
the second side plate 36 are placed in parallel on the bottom plate
34 with a predetermined clearance therebetween.
[0054] Next, as illustrated in FIG. 6C, with the first side plate
35 and the second side plate 36 being fixed at the predetermined
positions LP, rear end portions of the first side plate 35 and the
second side plate 36 are pushed outward using a lining. More
specifically, as illustrated in FIG. 7, with a pair of pressing
tools 40 abutting against the predetermined positions LP on outer
surfaces of the first side plate 35 and the second side plate 36, a
lining tool 41 applies outward pressure to inner surfaces of the
rear end portions of the first side plate 35 and the second side
plate 36. At this time, the lining is adjusted to cause elastic
deformation within a range that does not plastically deform the
first side plate 35 and the second side plate 36.
[0055] Next, as illustrated in FIG. 6D, the base end bracket 31 is
inserted between the respective rear end portions of the first side
plate 35 and the second side plate 36 that have elastically
deformed outward, and then the lining is removed, to thereby
sandwich and fix the base end bracket 31 between the respective
rear end portions of the first side plate 35 and the second side
plate 36. Then, the bottom plate 34 and the first side plate 35 are
welded together and the bottom plate 34 and the second side plate
36 are welded together. In addition, the base end bracket 31 is
temporarily mounted to the first side plate 35 from the inner side,
and the base end bracket 31 is temporarily mounted to and the
second side plate 36 from the inner side.
[0056] Next, as illustrated in FIG. 6E, the top plate 33 is placed
on top of the first side plate 35 and the second side plate 36.
Then, the top plate 33 and the first side plate 35 are welded
together and the top plate 33 and the second side plate 36 are
welded together, to thereby fix the top plate 33.
[0057] The boom 17 includes the body 30 and the base end bracket
31. The body 30 includes the straight section 30a and the wide
section 30b. When viewed from above, the width Wa of the straight
section 30a is substantially constant. When viewed from above, the
width Wb of the wide section 30b increases toward the base end
bracket 31. The straight section 30a and the wide section 30b are
smoothly continuous to each other.
[0058] As described above, because the wide section 30b is
configured to increase in the width Wb toward the base end bracket
31, the bending strength of the wide section 30b at the sides can
be improved. In addition, because the straight section 30a and the
wide section 30b are smoothly continuous to each other, it is
possible to reduce locally concentrating stresses in the body
30.
[0059] In the above-described embodiment, a case has been described
in which a "box-shaped structure for a work machine" according to
the present invention is applied to the boom 17, but the present
invention is not limited thereto. The "box-shaped structure for a
work machine" according to the present invention can also be
applied to the arm 18. Even in this case, durability of the arm 18
can be improved with the body of the arm 18 having a width that
increases toward the base end side bracket 18b.
[0060] In the above-described embodiment, as illustrated in FIG.
6C, the first side plate 35 and the second side plate 36 are pushed
outward using a lining, but the first side plate 35 and the second
side plate 36 may be pushed outward by pushing the base end bracket
31 in between the first side plate 35 and the second side plate
36.
[0061] In the above-described example, the end boss EB that extends
in the width direction is separately provided on the base end
bracket 31, but the base end bracket 31 and the end boss EB may be
formed integrally.
[0062] In the above-described example, an ingot formed by casting a
metal material is used for the base end bracket 31, but the base
end bracket 31 may be formed by forging or be formed of a metal
plate.
* * * * *