JP3669001B2 - Swivel fitting for working equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a swivel joint, and more particularly to a swivel joint used in a soil improvement machine. For the sake of convenience, in the description in the following description, the front side of the soil improvement machine (there is a stirring blade, an excavation head, etc.) is referred to as “front”, and the drive side is referred to as “rear”.
[0002]
[Prior art]
As an example of a working device including a swivel joint, an overall view of a soil improvement machine is schematically shown in FIG. This soil improvement machine supplies hardened material such as cement milk while digging the soil with the excavation head 11 at the tip, and stirs and mixes with the existing soil (laying ground) with the stirring blade 9, so that the soft soil is removed. It is hardened by consolidation. That is, when the rotating shaft 1a of the driving device 1 rotates, the rotation is transmitted to the outer tubular shaft 5 through the swivel joint 3, and the stirring blade 9 at the tip rotates. Further, since the rotational power of the driving device 1 is also transmitted to the inner shaft 7, the excavation head 11 at the tip rotates to dig up the soil. Since the hardened material injected under pressure from the hardener inlet provided in the swivel joint is discharged from the hardener outlet 13 at the tip through the gap 21 between the outer tubular shaft and the inner shaft, the excavation head The soft soil dug up by 11 is mixed with the hardener by the stirring blade 9 and solidified by a chemical reaction of the hardener to form a hard pile.
[0003]
A conventional swivel joint 3 used in such a soil improvement machine includes a casing 15 supported by a support column 14 and a bearing 17 provided in the casing 15 as shown in a partial sectional view of FIG. The inner shaft 7 is inserted through the inner hollow shaft 19 in a concentric manner.
[0004]
A flange 27a is connected to one end (rear end) of the inner hollow shaft 19 via a key 29, and is connected to a flange portion of the rotary shaft 1a on the drive device 1 side by a bolt or the like. On the other hand, the flange 27b at the other end (front end) of the inner hollow shaft 19 is connected to the outer tubular shaft 5 having the stirring blade 9 attached to the tip. A gap 21 having an annular cross section is formed between the inner hollow shaft 19 and the outer tubular shaft 5 and the inner shaft 7. A predetermined position of the casing 15 is provided with a hardening material injection passage 23 for injecting the hardening material into the gap 21 and a hardening material injection port 23a as an inlet thereof. And communicates with the gap 21 through the inner hollow shaft 19. Further, the gap 21 reaches the above-mentioned hardener discharge port 13 at the tip (see FIG. 4). Further, an annular packing 25 is provided between the casing 15 and the inner hollow shaft 19 so that the hardener passing through the hardener injection passage 23 does not leak outside by sandwiching the hardener injection passage 23 in the axial direction. It is arranged.
[0005]
[Problems to be solved by the invention]
In the conventional swivel joint of the soil improvement machine, as described above, the packing 25 is provided before and after the hardener injection passage 23 in order to prevent leakage of the hardener injected from the hardener inlet. However, since pressure is applied during the injection of the hardener, the hardener may enter between the sliding surfaces of the packing 25 and the inner hollow shaft 19, and the sliding surface of the inner hollow shaft, that is, the packing seal surface, is significantly worn. It was sometimes damaged. As a result, the hardened material passes through the front or rear packing 25 from between the casing 15 and the inner hollow shaft 19 and leaks to the outside. Therefore, the soil and hardener are mixed by the stirring blade 9 at the tip. When combining, there was a possibility that a suitable mixing ratio could not be obtained.
[0006]
Furthermore, during the operation of the soil improvement machine, the rotational vibrations of the stirring blade 9 and the excavation head 11 at the tip are also transmitted to the swivel joint 3. However, the conventional swivel joint has a bearing 17 only on the rear side of the casing 15. Since the outer tubular shaft 5 and the inner hollow shaft 19 are smoothly rotated and steady, the above-mentioned vibration concentrates on the packing 25 on the front side of the bearing 17 to cause damage. It has been known not only to significantly reduce the average life of itself, but also to accelerate wear damage on the packing seal surface of the inner hollow shaft 19. Moreover, even if it replaces damaged packing, since it is necessary to disassemble a soil improvement machine, there also exists a problem in which work efficiency falls significantly.
[0007]
Accordingly, a main object of the present invention is to provide a swivel joint in which the sliding surface of the hollow shaft, that is, the packing seal surface is less likely to be damaged by wear.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the swivel joint of the present invention is connected to the rotating shaft of the drive device at one end, connected to the outer tubular shaft at the other end, and has a second gap communicating with the first gap. A rotatable inner hollow shaft disposed around the inner shaft, a casing disposed around the inner hollow shaft, a bearing device disposed between the inner hollow shaft and the casing, and the second In a swivel joint having a low pressure fluid injection passage formed radially through the casing and the inner hollow shaft so as to communicate with the gap, annulus is formed between the casing and the inner hollow shaft on both sides of the low pressure fluid injection passage in the axial direction. A high-pressure fluid injection passage is formed in the casing so as to open to the first and second annular packings between the casing and the inner hollow shaft on both sides of the high-pressure fluid injection passage in the axial direction.
[0009]
In addition, an elastic member may be disposed between the casing and the inner hollow shaft to urge each of the second annular packings positioned away from the low pressure fluid injection passage in the axial direction toward the low pressure fluid injection passage. .
Further, in the swivel joint of the soil improvement machine, the hardener is injected into the low pressure fluid injection passage as a relatively low pressure fluid, and water is injected into the high pressure fluid injection passage as the relatively high pressure fluid.
[0011]
[Action]
When the rotating shaft and the inner shaft are rotated by the driving device of the working device, the inner hollow shaft whose one end is connected to the rotating shaft rotates, and the outer tubular shaft connected to the other end of the inner hollow shaft is also rotated. The relatively low-pressure fluid injected under pressure from the low-pressure fluid injection passage that penetrates the casing and the inner hollow shaft is supplied to the tip through the second gap and the first gap. A relatively high pressure fluid is injected under pressure from the high pressure fluid injection passages on both sides of the low pressure fluid injection passage, and acts on the first annular packing. For this reason, even if the low-pressure fluid is likely to enter between the first annular packing and the inner hollow shaft, the high-pressure fluid flows into the low-pressure fluid injection passage through this space. The low-pressure fluid does not leak from the low-pressure fluid injection passage and enter between the first annular packing and the inner hollow shaft.
[0012]
Further, if an elastic member for urging each of the second annular packings on one side of the high-pressure fluid injection passage to the low-pressure fluid injection passage side is provided, the pressure necessary for sealing is maintained even if the second annular packing is worn. Continue to be secured.
Further, when the work machine is used as a soil improvement machine, a hardening material is supplied as a low-pressure fluid, and water is supplied as a high-pressure fluid.
Further, in the case where bearings for supporting the inner hollow shaft are provided at both ends of the casing, harmful vibrations accompanying rotation of the inner hollow shaft are not substantially transmitted to the annular packing between the bearings.
[0013]
【Example】
Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which the same reference numerals denote the same or corresponding parts.
FIG. 1 shows an overall view of a soil improvement machine (working apparatus) including an embodiment of a swivel joint according to the present invention. FIG. 2 shows an enlarged partial cross-sectional view of the swivel joint of this embodiment. In addition, in this soil improvement machine, since parts other than the swivel joint are the same as the conventional one, detailed description of the part is omitted.
[0014]
In the soil improvement machine, the driving device 1 is a power source for rotating the rotating shaft 1a and the inner shaft 7. The inner shaft 7 penetrates through the swivel joint 103 and extends in the front-rear direction. The excavation head 11 is attached and fixed to the distal end of the inner shaft 7, and the proximal end is connected to the driving device 1. On the other hand, the flange portion of the rotating shaft 1 a is connected to one end on the swivel joint 103 side, and the other end is connected to the flange portion of the outer tubular shaft 5. The swivel joint 103 is located between the drive device 1 of the soil improvement machine and the outer tubular shaft 5, and connects the two at the hollow shaft portion. Further, a stirring blade 9 is attached and fixed to the tip of the outer tubular shaft 5. A gap 21 formed between the outer tubular shaft 5 and the inner shaft 7 communicates with the curing material discharge port 13 at the tip.
[0015]
Next, the swivel joint 103 will be described in detail. The swivel joint 103 in FIG. 2 mainly includes a hollow casing 115 supported by a support column 114 and an inner hollow shaft 119. The inner shaft 7 is partially inserted into the hollow portion of the inner hollow shaft 119 and extends long in the front-rear direction through the inner hollow shaft 119. Between the radial directions of the inner shaft 7 and the inner hollow shaft 119, a gap 122 having an annular cross section (hereinafter referred to as a second gap) is formed. The second gap 122 is substantially formed at a portion in front of a hardener injection passage (low-pressure fluid injection passage) 123 described later, and between the inner shaft 7 and the outer tubular shaft 5 in the radial direction. A similar gap 121 (hereinafter referred to as a first gap) is formed in the annular cross section, and communicates with the hardener discharge port 13 at the tip. In order to perform smooth rotation and steadying of the outer tubular shaft 5 and the inner hollow shaft 119, the inner hollow shaft 119 is rotatably supported by bearings 117 disposed at respective ends in the front-rear direction of the casing 115. A flange 127a is connected to the rear end portion of the inner hollow shaft 119 by screwing, and the flange 127a is connected to the flange portion of the rotary shaft 1a described above by means such as a bolt. On the other hand, a flange 127b is connected to the front end portion of the inner hollow shaft 119 in the same manner, and the flange 127b is connected to the flange portion of the outer tubular shaft 5 by means such as a bolt.
[0016]
In addition to the bearing 117, a hardener injection passage 123, a first annular packing 125, a water injection passage 131, a second annular packing 133, a disc spring 135, and the like are provided inside or inside the casing 115. First, a hardener injection passage 123 is provided at a substantially central position between the two bearings 117, and the hardener injection port 123 a connected to a hardener supply source (not shown) is more than the outer shape of the casing 115. It protrudes. The hardener injection passage 123 passes through the casing 115 and further passes through the inner hollow shaft 119 and communicates with the second gap 122. In the present embodiment, the number of the hardener injection passages 123 is three in total at three positions spaced apart by about 90 ° in the circumferential direction, but the present invention is not limited to this.
[0017]
Further, on both sides immediately before and after the hardener injection passage 123, the hardener leached from the hardener injection passage 123 between the casing 115 and the inner hollow shaft 119 is further outward (front-rear direction) with respect to the hardener injection passage 123. In order to prevent leakage, an annular first annular packing 125 such as an O-ring, which is fitted in a groove formed on the inner peripheral surface of the casing 115, is provided as an auxiliary. As can be seen from FIG. 2, the swivel joint 103 of the present embodiment is symmetrical with respect to the hardening material injection passage 123, so that the following description will be given in front of the hardening material injection passage 123.
[0018]
In front of the first annular packing 125, a water injection passage (high-pressure fluid injection passage) 131 having an inlet 131a opened on the outer peripheral surface of the casing 115 is provided. FIG. 3 shows a view taken along the line III-III in FIG. 2 passing through the water injection passage 131. The water injection passage 131 includes an annular space portion 131b formed between the casing 115 and the inner hollow shaft 119, and a tube portion 131c extending from the injection port 131a to the space portion 131b. The injection port 131a of the present embodiment is provided only in one place, but the number and orientation of the injection ports 131a are not limited to this embodiment as in the case of the hardener injection port 123a. Absent. A fluid having a pressure higher than that of the hardened material injected from the injection port (in practice, “water” is used) is filled in the annular space 131b, and the casing 115 and the inner hollow space are filled. It leaks little by little in the front-rear direction from between the shaft 119.
[0019]
Further, a normal gland packing, that is, a second annular packing 133 is disposed in front of the water injection passage 131. The second annular packing 133 prevents the water injected into the water injection passage 131 from leaking forward, opposite to the first annular packing 125.
[0020]
Further, a packing presser 137, a plurality of disc springs 135, and a sleeve 139 are disposed between the second annular packing 133 and the bearing 117. The disc spring 135 is a disc-shaped spring having a hole having substantially the same diameter as the outer diameter of the inner hollow shaft 119, and the outer peripheral end of one disc spring 135 is in contact with the outer peripheral end of the adjacent disc spring 135. A plurality of peripheral ends are arranged in the front-rear direction along the outer peripheral surface of the inner hollow shaft 119 in such a manner as to contact the inner peripheral end of the adjacent disc spring 135. An annular sleeve 139 is provided between the disc spring 135 and the casing 115, and the compression force of the disc spring 135 is uniformly applied to the second annular packing 133 between the disc spring 135 and the second annular packing 133. An annular packing retainer 137 is disposed so as to be transmitted. Since the disc spring 135 is compressed more than the unloaded state in the assembled state shown in FIG. 2, a compressive force is always elastically applied to the second annular packing 133 via the packing presser 137. Even when the second annular packing 133 is worn, its diameter is increased by compression so that a sufficient sealing force is always obtained.
End lids 143 are attached to the front and rear ends of the casing 115 to hold the bearing 117 and close the front and rear ends. An annular bushing 141 is disposed between the end lid 143 and the inner hollow shaft 119 in preparation for the rotation of the inner hollow shaft 119.
[0021]
Next, operation | movement of the soil improvement machine containing the swivel joint 103 of a present Example is demonstrated. When the driving device 1 operates, the rotating shaft 1a and the inner shaft 7 rotate in a predetermined direction. The rotation of the inner shaft 7 is directly transmitted to the tip without being transmitted to other members such as the swivel joint 103 and the outer tubular shaft 5 to rotate the excavation head 11. On the other hand, the rotation of the rotating shaft 1a is transmitted to a flange 127a connected by a bolt or the like, and is transmitted to the inner hollow shaft 119 via a key, and further to the flange 127b via a key at the front end. 5 and the stirring blade 9 at the tip thereof is rotated. At that time, since the inner hollow shaft 119 is supported by two bearings 117 located at each end of the casing 115, the inner hollow shaft 119 is effectively prevented from shaking, and the member between the bearings 117 is attached to the member between the bearings 117. No harmful vibrations accompanying the rotation of the inner hollow shaft 119 are substantially not transmitted.
[0022]
Separately from the operation of the driving device 1, a relatively low-pressure hardener is poured into the hardener injection passage 123 and passes through the second gap 122 and the first gap 121 to the hardener discharge port 13 at the tip. Supplied. As a result, the soil dug up by the excavating head 11 is mixed with the hardener by the rotation of the agitating blade 9 described above. Further, the water injection passage 131 before and after the hardening material injection passage 123 has no adverse effect even if mixed with the hardening material, and even if it enters between the sliding surfaces of the packing and the inner hollow shaft, it does not adversely affect the packing seal surface. No fluid (water in this embodiment) is constantly being injected at a pressure relatively higher than the pressure of the hardener, and gradually passes between the inner hollow shaft 119 and the first annular packing 125. It continues to enter the injection passage 123. For this reason, since the hardener cannot overcome water having a pressure higher than itself and cannot leach into the sealing surface of the inner hollow shaft with respect to the first annular packing 125, it is prevented from leaking from the middle of the hardener injection passage 123. Has been.
[0023]
【The invention's effect】
As described above, according to the swivel joint of the present invention described in claim 1, the high pressure fluid formed in the casing so as to open annularly between the casing and the inner hollow shaft on both sides of the low pressure fluid injection passage. Since the injection passage and the first and second annular packings disposed between the casing and the inner hollow shaft on both sides of each of the high-pressure fluid injection passages, the high-pressure fluid flows between the first annular packing and the inner hollow. Since the gap between the shafts is blocked, low-pressure fluid is prevented from reaching the second annular packing (gland packing), and the seal surface of the inner hollow shaft contacting the first and second annular packings can be significantly damaged by wear. Is prevented.
[0024]
According to the swivel joint of the second aspect, the elastic member that urges each of the second annular packings located at the positions separated from the low-pressure fluid injection passage toward the low-pressure fluid injection passage is disposed, and the elastic member causes the first Since the two-ring packing is always compressed, even if the sliding surface with the inner hollow shaft wears, the surface pressure required for sealing the sliding surface is ensured by expanding in the radial direction by the compression. High-pressure fluid is prevented from leaking from between the two annular packings and the inner hollow shaft.
[0025]
According to the swivel joint of claim 3, when used in a soil improvement machine, the hardener is supplied as a relatively low-pressure fluid injected into the low-pressure fluid injection passage, and relative to the high-pressure fluid injection passage. Since water is supplied as a high-pressure fluid, there is no problem even if water is mixed into the hardener, and there is no problem because the affinity is good. In addition, the life of the gland packing when a slurry such as cement milk enters Compared to the above, the life of the second annular packing is improved by 10 times or more.
[0027]
According to the swivel joint of the fourth aspect , the pair of bearings disposed between the inner hollow shaft and the casing in the vicinity of the end portion of the casing, and the second gap between the pair of bearings communicate with the second gap. Formed in the casing so as to open annularly between the casing and the inner hollow shaft on both sides of the low pressure curing material injection passage with respect to the axial direction. Each of the first and second annular packings disposed between the casing and the inner hollow shaft on both sides of each of the high-pressure water injection passages in the axial direction. An elastic member biased toward the low-pressure hardener injection passage, and between the pair of bearings, the low-pressure hardener injection passage, the high-pressure water injection passage, the first and second annular packings, Arranged with the elastic member Because they are, it exhibits the full effect of the invention of claim 1 to 3, specifically, with respect to the average time available continuous operation of the conventional swivel joint shown in FIG. 5 is 40-50 hours The continuous operation of 300 hours or more becomes possible, and maintenance can be omitted for about one month, which is the average construction period per soil improvement work, so that the construction period can be greatly shortened.
[Brief description of the drawings]
FIG. 1 is an overall schematic view of a soil improvement machine including a swivel joint according to an embodiment of the present invention.
FIG. 2 is an enlarged partial cross-sectional view of the swivel joint in the soil improvement machine of FIG. 1 enlarged, showing the upper half in cross section and the lower half in side view.
3 is a partial cross-sectional view taken along the line III-III of FIG. 2 passing through the high-pressure water injection passage.
FIG. 4 is an overall view of a soil improvement machine including a conventional swivel joint.
5 is an enlarged partial cross-sectional view in which the swivel joint of FIG. 4 is enlarged and the upper half is shown in cross section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Drive device, 1a ... Rotating shaft, 5 ... Outer tubular shaft, 7 ... Inner shaft, 115 ... Casing, 117 ... Bearing (bearing device), 119 ... Inner hollow shaft, 121 ... First clearance, 122 ... Second , 123 ... hardening material injection passage (low pressure fluid injection passage, fluid injection passage), 125 ... first annular packing, 131 ... water injection passage (high pressure fluid injection passage), 133 ... second annular packing, 135 ... disc spring (Elastic member).

Claims (4)

  A rotatable inner shaft, an outer tubular shaft rotatably disposed with a first gap in the radial direction around the inner shaft, and a driving device for driving the inner shaft and the outer tubular shaft A swivel joint of a working device having one end connected to the rotating shaft of the drive device at one end, and connected to the outer tubular shaft at the other end, and a second gap communicating with the first gap. A rotatable inner hollow shaft disposed around the inner shaft, a casing disposed around the inner hollow shaft, a bearing device disposed between the inner hollow shaft and the casing, A low pressure fluid injection passage formed radially through the casing and the inner hollow shaft so as to communicate with the second gap, and the casing and the inner hollow shaft on both sides of the low pressure fluid injection passage in the axial direction. Open in a ring between A high-pressure fluid injection passage formed in the casing, and first and second annular packings disposed between the casing and the inner hollow shaft on both sides of the high-pressure fluid injection passage in the axial direction. A swivel joint provided.   An elastic member is provided between the casing and the inner hollow shaft and biases each of the second annular packings located at a position spaced apart from the low-pressure fluid injection passage in the axial direction toward the low-pressure fluid injection passage. The swivel joint according to claim 1.   The working device is supplied with a hardener as a relatively low pressure fluid injected into the low pressure fluid injection passage and supplied with water as a relatively high pressure fluid injected into the high pressure fluid injection passage. The swivel joint according to claim 1 or 2, which is a machine. A rotatable inner shaft, an outer tubular shaft rotatably disposed with a first gap in the radial direction around the inner shaft, and a driving device for driving the inner shaft and the outer tubular shaft A second swivel joint of a soil improvement machine having one end connected to the rotating shaft of the drive device at one end and the other end connected to the outer tubular shaft and communicating with the first gap. A rotatable inner hollow shaft disposed around the inner shaft, a casing disposed around the inner hollow shaft, and between the inner hollow shaft and the casing near an end of the casing. A pair of disposed bearings, and a low-pressure hardener injection passage formed radially through the casing and the inner hollow shaft so as to communicate with the second gap between the pair of bearings; Both sides of the low-pressure hardener injection passage with respect to the axial direction A high-pressure water injection passage formed in the casing so as to open annularly between the casing and the inner hollow shaft; and between the casing and the inner hollow shaft on both sides of the high-pressure water injection passage in the axial direction. And an elastic member for urging each of the second annular packings toward the low-pressure hardener injection passage, and the low-pressure member is interposed between the pair of bearings. A swivel joint in which a hardener injection passage, the high-pressure water injection passage, the first and second annular packings, and the elastic member are disposed.

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