JP3574355B2 - Swivel joint of swivel work machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a swivel joint of a turning work machine, and more specifically, to a swivel joint for distributing hydraulic oil in a hydraulic shovel such as a backhoe.
[0002]
[Prior art]
BACKGROUND ART A turning work machine such as a backhoe has a revolving body (slewing body) equipped with an engine or the like mounted so as to be rotatable around a vertical axis with respect to a traveling body (a truck frame or the like) positioned below. A swivel joint is provided between the body and the traveling body for mutually distributing and circulating hydraulic oil.
Referring to FIG. 9, a conventional swivel joint 1 will be described. An outer 5 to which a hydraulic pipe 4 is connected is fitted on a shaft 3 having a drain oil passage 2 in the axial direction, and a bottom portion of the outer 5 is provided. A lid 6 for sealing the oil from the drain oil passage 2. The lid 6 is provided with a plurality of lids, not shown, for closely attaching a seal ring 7 such as an O-ring to an interface with the bottom surface of the outer 5. It is fastened to the bottom of the outer 5 by the bolts.
[0003]
The shaft 3 is prevented from coming off in the axial direction by a collar 8 and a retaining ring 9, and the lid 6 is made of a casting. A drain hole 6A for connecting a drain pipe communicates with the drain oil passage 2. Have been.
[0004]
[Problems to be solved by the invention]
In the conventional swivel joint 1, oil leakage from the interface (seal surface) S between the outer 5 and the lid 6 is performed by the seal ring 7 interposed on the horizontal plane.
Therefore, the sealing characteristics (seal accuracy) are governed by the smoothness (adhesion) of the interface, and are also governed by the adhesion (pressability) and elastic restoring force of the seal ring 7.
[0005]
However, in a turning work machine such as a backhoe, since excavation work is performed using a bucket or the like, the seal surface S separates (separates) due to an impact or the like due to the work load, causing oil leakage.
Further, in order to prevent oil leakage, the bolts for fastening the lid 6 to the outer 5 must be tightened. However, since the bolts are located at the bottom of the traveling body (trek frame), the bolts are increased. Tightening work is difficult, and the durability of the seal ring 7 is low due to the above-mentioned impact and additional tightening, so that it is almost impossible to avoid oil leakage.
[0006]
In view of the above, an object of the present invention is to make the sealing surface vertical rather than horizontal, thereby ensuring the sealing characteristics even when the above-described impact or the like acts, and to reliably prevent oil leakage. Things.
[0007]
[Means for Solving the Problems]
The present invention includes an outer 30 having a hydraulic pipe 29 connected to a shaft 28 having a drain oil passage 27 extending in the axial direction. The outer 30 is sealed with oil from the drain oil passage 27 at the bottom of the outer 30. This is a swivel joint of a turning work machine provided with a lid 32 that performs the following technical measures in order to achieve the above-mentioned object.
That is, according to the first aspect of the present invention, the lid 32 is fitted to the bottom cylindrical portion 30A of the outer 30, and the outer peripheral surface of the lid 32 and the inner peripheral surface of the bottom cylindrical portion 30A are annularly sealed. It is characterized in that a ring 31 is mounted and a retaining means 33 for preventing the lid 32 from coming off in the axial direction is provided on the bottom side of the lid 32.
[0008]
By adopting such a configuration, the seal ring 31 is not a face seal but a shaft seal, and the seal face is an annular vertical face. There was no separation and no pressure on the seal ring 31, which reliably prevented oil leakage and improved the durability of the seal ring 31, thereby reducing maintenance.
In claim 1 described above, it is recommended that the retaining means 33 is a retaining ring 34 for a hole that can be fitted into a peripheral groove 30B formed in the inner peripheral surface of the bottom cylindrical portion 30A (claim 2). .
[0009]
With such a configuration, the lid 32 seals the drain oil with the seal ring 31. Since the drain has a low pressure, the retaining of the lid 32 can be secured by the simple configuration of the retaining ring 35 for the hole. Therefore, maintenance can be performed easily and quickly even with a small number of maintenance opportunities, and the maintainability is improved.
Furthermore, in the above-mentioned claim 1 or 2, the lid 32 has an engagement portion 35 formed on the bottom surface side for mounting and dismounting the lid 32 in the axial direction with respect to the bottom cylindrical portion 30A. (Claim 3).
[0010]
By adopting such a configuration, the operation of detaching the stopper 32 in the axial direction by, for example, screwing a removal bolt, a removal tool, or the like into the engagement portion 35 after detaching the retaining member 33 is simplified. In addition, when this work is performed in a place where the bottom space is narrow, the maintainability is greatly improved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an entire backhoe as an example of a turning work machine 10 equipped with a swivel joint according to the present invention, and a traveling body (trek frame) 12 having left and right crawlers 11 has an upper surface at a central portion thereof. A swivel body 14 is supported via a swivel bearing 13 so as to be able to make a full turn (360 ° rotation) about a vertical axis 0-0.
[0012]
The turning body 14 is equipped with a control unit 16 including a driver's seat 15 and an engine, and the engine is covered with a hood 17 that can be opened and closed.
A swing bracket 18 is provided at the front of the revolving machine body 14 so as to be rotatable around a vertical axis. A working tool 19 is mounted on the bracket 18 so as to be able to move up and down and bendably. The excavator exemplified by the bucket 20 enables excavation work by each hydraulic cylinder 21, and a dozer 22 is mounted between the right and left crawlers 11 and in front of the traveling body 12 so as to be able to move up and down.
[0013]
Referring to FIGS. 2 and 3, a swivel joint 26 according to the present invention is mounted on a board (bottom plate) 23 of the traveling body 12 via a flat stay 24 and bolts 25.
More specifically, a swivel joint 26 is attached concentrically to the center of the traveling body 12 (on the pivot axis 0-0), and the joint 26 is a shaft 28 having a drain oil passage 27 in the axial direction. And a cylindrical outer 30 to which a hydraulic pipe 29 is connected (connected) is provided with a sleeve, and the bottom of the outer 30 is sealed with oil from the drain oil passage 27 via a ring-shaped seal ring 31. It has a disk-shaped lid 32.
[0014]
The lid 32 is fitted to the bottom cylindrical portion 30A of the outer 30. An annular seal ring 31 is attached to the outer peripheral surface of the lid 32 and the inner peripheral surface of the bottom cylindrical portion 30A. A stopper means 33 for preventing the body 32 from coming off in the axial direction is provided on the bottom surface side of the lid body 32.
The retaining means 33 comprises a hole retaining ring 34 that can be fitted in a peripheral groove 30B formed on the inner peripheral surface of the bottom cylindrical portion 30A.
Further, the cover 32 has an engaging portion 35 for mounting and dismounting the cover 32 in the axial direction with respect to the bottom cylindrical portion 30A. In this embodiment, a blind screw hole is provided on the bottom surface side of the cover 32. Is formed.
[0015]
Here, the seal ring 31 exemplified by the O-ring functions not as a face seal but as a shaft seal. Therefore, even if a vertical impact, bending, or the like acts on the seal ring 31 (seal surface) due to excavation work or the like, the seal ring 31 does not function. Since the sealing surface is a vertical surface (cylindrical surface), it is difficult for external force to act on the sealing ring 31, thereby improving the durability and maintaining a reliable sealing function.
An axial stepped portion 30C is formed on the inner surface (inner peripheral surface) of the bottom cylindrical portion 30A, and the upper end peripheral edge of the lid 32 contacts the stepped portion 30C from below, thereby positioning in the axial direction. In this position, the lid 32 is prevented from being removed by the retaining means 33.
[0016]
An oil chamber (oil passage) 35 for distributing oil pressure to each actuator is defined in the axial direction by the shaft 28 and a groove formed on the inner peripheral surface of the outer 30. Each oil chamber 35 is a seal exemplified by an O-ring. The ring 28 is oil-tightly sealed, and the shaft 28 is axially positioned by a collar 37 and a shaft retaining ring 38.
In each oil chamber 35, a pipe 39 for distributing hydraulic oil from a hydraulic source (pump or the like) mounted on the turning machine body 14 to a traveling motor of the crawler 11, a hydraulic cylinder of the dozer 22, and the like are shown in FIG. As shown, a stopper 40 for preventing rotation is mounted on the head of the shaft 28.
[0017]
A drain hole 29A is formed, for example, as a screw hole on the bottom side of the outer (body) 30. A pipe (drain pipe) 29 is connected to the drain hole 29A via a screw plug or the like.
For this reason, since a high pressure does not act on the lid 32 and only a relatively low pressure drain hydraulic pressure acts on the lid 32, the retaining ring 34 is sufficient as the retaining means 33, and the lid 32 is connected to the outer 30. Not only substantially lowers the joint 26 but also reduces collision and contact with earth and sand.
[0018]
An inspection window 23A is formed in the bottom plate 23 of the traveling body 12, and a hole 24A is also formed in the stay 24 in the same shape as the window 23A, through which the cover 32 engages with the engaging portion 35 with a bolt. The shaft 28 can be attached and detached in the axial direction, and the shaft 28 can be maintained.
The inspection window 23A has a bottom cover 41 which can be detachably attached, and the joint 26 is protected against mud.
With reference to FIGS. 3 to 6, the center of the traveling body 12 is formed in a box-shaped frame portion 44 via a bottom plate 23, a top plate (mounting base for the slewing bearing 13) 42, a rib 43, and the like. Legs 45 are extended in front and rear and left and right of the box-shaped frame portion 44 in an X-shaped arrangement in plan view, and a crawler mounting frame 46 is extended on the leg portion 45 in the front-rear direction.
[0019]
The stay 24 is formed in an elongated flat plate shape in a plan view, and both ends thereof are fixed to the bottom plate 23 via a plurality of bolts 25, and the joint 26 is attached to the bottom plate 23 by being fastened together. As shown in FIG. 3, the stay 24 may be mounted on the long side in the left-right direction, or may be mounted on the long side in the front-rear direction as shown in FIG.
However, when mounted as shown in FIG. 3, the load on the bolt 25 due to excavation resistance, impact, and the like is advantageously smaller than in the mounting mode of FIG.
[0020]
In any of the mounting modes, the stay 24 can be formed integrally with the bottom of the outer (body) 30. In this case, the stay 24 has a mounting seat for the joint 26 formed integrally.
As shown in FIGS. 3 and 5, the dozer 22 is mounted on the front side of the box-shaped frame portion 44.
The dozer 22 includes left and right arms 48 formed of metal square tubes on the left and right sides of a discharge plate 47 extending back and forth, and the base of the left and right arms 48 is attached to a bracket 49 on the front side of the box-shaped frame portion 44. And a pin so as to be able to move up and down.
[0021]
FIGS. 7A and 7B show two examples of the dozer 22.
That is, a triangular reinforcing plate (box) 51 is welded and reinforced at a corner portion between the back surface of the earth discharging plate 47 and the left and right arms 48, and the left and right arms 48 are welded to the substrate 52A in FIG. Are connected by a connecting member 52 shown by a round pipe (round bar pipe).
In FIG. 7A, since the substrate 52A is interposed, stress concentration at the joint between the arm 48 and the connecting member 52 is reduced, but the manufacturing cost is increased.
[0022]
On the other hand, in FIG. 7 (2), a hole in the left and right direction without the arm 48 is formed, the connecting material 52 is inserted into this hole, and welding 53A and 53B are performed inside and outside. The blindness of the welding 53A improves the durability, reduces the diameter of the connecting member 52, and reduces the number of welding points, thereby reducing costs.
FIGS. 8A and 8B show two examples of a pivotal support portion of the dozer arm (left and right arms) 48 with respect to the bracket 49.
[0023]
In FIG. 8A, the arm base 54 and the fulcrum boss 55 are sealed by welding two upper and lower reinforcing plates 56A and 56B. According to this, not only is the welding length increased, but also two reinforcing plates 56A and 56B are required, and the bending of the plates is increased.
On the other hand, in FIG. 8 (2), the boss 55 is eccentrically welded so that the upper edge 54A of the arm base 54 contacts the upper edge of the fulcrum boss 55, and the lower reinforcing plate 56B is positioned below the boss 55. Only the bending process is performed along the peripheral surface, so that the welding length is short, the bending process only needs to be performed once, and the upper reinforcing plate can be saved.
[0024]
【The invention's effect】
As described in detail above, according to the present invention, the height of the swivel joint can be reduced, and not only the assembling and disassembly becomes easy, but also by using a shaft seal, even if an impact load or the like is repeatedly applied. The sealability can be reliably maintained, and the maintainability is also improved.
[Brief description of the drawings]
FIG. 1 is an overall side view of a turning work machine to which the present invention is applied.
FIG. 2 is a vertical sectional view of the swivel joint according to the present invention.
FIG. 3 is a plan view showing a first example of a traveling body (trek frame) equipped with a swivel joint according to the present invention.
FIG. 4 is a sectional view taken along line AA of FIG. 3;
FIG. 5 is a plan view showing a second example of a traveling body (track frame) equipped with a swivel joint according to the present invention.
FIG. 6 is a sectional view taken along line BB of FIG. 5;
FIGS. 7A and 7B show two examples of a dozer. FIG. 7A is a plan view and a side view of a first example, and FIG. 7B is a plan view and a side view of a second example.
FIGS. 8A and 8B show two examples of a pivot portion of a dozer, wherein FIG. 8A is a side view of a first example, and FIG. 8B is a side view of a second example.
FIG. 9 is a vertical sectional view showing a conventional swivel joint.
[Explanation of symbols]
27 Drain oil passage 28 Shaft 29 Hydraulic piping 30 Outer (body)
30A Bottom tube part 31 Seal ring 32 Lid 33 Detachment means

Claims (2)

An outer (30) having a hydraulic pipe (29) connected thereto is fitted over a shaft (28) having a drain oil passage (27) in the axial direction, and the drain oil passage is provided at the bottom of the outer (30). A lid (32) for sealing oil from (27) is provided, and the shaft (28) is axially positioned on the upper end side of the inner peripheral surface of the bottom cylindrical portion (30A) of the outer (30). A collar (37) is provided, a shaft retaining ring (38) is provided on a shaft (28) below the collar (37), and the lid (32) is fitted on the inner peripheral surface of the bottom tubular portion (30A). together they are if, in the axial positioning is made from below the stepped portion formed in an intermediate portion of the bottom tubular portion (30A) (30C) in contact with, the bottom cylinder and the outer peripheral surface of the lid member (32) An annular seal ring (31) is mounted on the inner peripheral surface of the portion (30A), and the lid (3 ) Axially missing retaining means for preventing (33) provided on the bottom side of the lid (32) of the retaining means (33) to form the bottom of the inner peripheral surface of the bottomed tubular portion (30A) A swivel joint for a turning working machine, wherein the swivel joint is formed by a retaining ring for a hole (34) that can be fitted into the circumferential groove (30B) . The lid (32) is provided with an engaging portion (35) for mounting and dismounting the lid (32) in the axial direction with respect to the bottom cylindrical portion (30A) on the bottom surface side. The swivel joint of the turning work machine according to claim 1 , wherein

Images