Universal joint for high-pressure piping

Abstract

To provide a universal joint for high-pressure piping that can be used in a compact configuration, has reduced pressure loss of high-pressure air and is compatible with various applications.SOLUTION: A piping joint 10 is configured to be screwed to an end of high-pressure piping. A universal joint 20 is configured to be inserted into the other end side of the piping joint 10. A fixing clamp 30 is configured to connect the piping joint 10 to the universal joint 20. An inflow port 24 continuing to an end of a flow channel 23 at right angle is formed. The inflow port 24 is formed so that an axis part of the inflow port 24 is aligned to an axis part of the flow channel 23.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a universal joint for high pressure piping used mainly in vehicle braking systems and the like, and more particularly to a universal joint for high pressure piping capable of reducing pressure loss inside the joint. [Background technology]

[0002] As a universal joint for piping, for example, a swivel elbow has been proposed as described in Patent Document 1. This swivel elbow is configured so that the connecting pipe connected via the elbow can be set in a desired direction, and has a structure in which a swivel elbow 10 perpendicular to the end of a nipple 11 is attached so as to be able to rotate freely, and a pipe connector 13 is connected to the end of this swivel elbow 10.

[0003] Also, a universal joint described in Patent Document 2 has been proposed as a universal joint for high-pressure piping. This universal joint is particularly usable for high-pressure piping used in braking systems, etc. That is, the structure is such that a straight universal joint 20 is rotatably connected to the end of a straight pipe joint 10 with a fixing clamp 30, a connection port 24 is formed on the side of this universal joint 20, and a connection pipe body 40 is connected to this connection port 24. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 57-51089 [Patent Document 2] Utility Model Registration No. 3225845 Summary of the Invention [Problem to be solved by the invention]

[0005] The swivel elbow 10 shown in Patent Document 1 has a configuration in which a connection pipe 17 is connected to a pipe connector 13, and the pipe connector 13 is positioned in a swivel direction relative to a nipple 11. However, because the intersection of the flow passages between the nipple 11 and the pipe connector 13 is sealed with packing 15, there is a risk that the packing 15 will deteriorate due to the rotation of the pipe connector 13, resulting in a problem of reduced sealing performance of the flow passage.

[0006] On the other hand, the universal joint described in Patent Document 2 has a compact structure in which a straight universal joint 20 is rotatably connected to the end of a straight pipe joint 10 by a fixed clamp 30. This makes it possible to use it in high-pressure pipes that are often arranged in limited spaces, such as braking systems that use high-pressure air.

[0007] However, this universal joint had a large pressure loss in the continuous portion of connecting port 24 that continues perpendicularly to flow passage 23 molded inside linear universal joint 20. That is, to make a universal joint compact, it is necessary to cut and form flow passage 23 and connecting port 24 inside linear universal joint 20. In this case, when inlet port 24 is formed perpendicularly to flow passage 23, extra space is generated in the continuous portion during the molding process.

[0008] That is, in the conventional cutting process, a linear flow passage 23 along the longitudinal direction of universal joint 20 is cut, and connecting port 24 that is continuous with this flow passage 23 at a right angle is cut into the side surface of universal joint 20. At this time, connecting port 24 is formed so that the open end of flow passage 23 is fully open. However, it was found that an extra space is generated when cutting connecting port 24, and many vortexes are generated when high-pressure air passes through this extra space in a turbulent manner, and these vortexes cause a large pressure loss.

[0009] This pressure loss leads to a slowdown of the high-pressure air, which is a major problem especially in vehicle braking systems. That is, in braking systems that use high-pressure air, the pressure loss can cause problems in the system. For this reason, universal joints that cause too much pressure loss cannot be used.

[0010] Furthermore, in the universal joint of Patent Document 2, there is a case where an L-shaped connecting pipe body 50, 60 that has been bent at a right angle in advance is connected to a straight universal joint 20. However, in the universal joint 20 in which the connecting port 24 is connected to the flow path 23 at a right angle, pressure loss occurs in the right-angled connecting portion, and when the pressure loss of the L-shaped connecting pipe body 50, 60 itself is added to this, the overall pressure loss increases.

[0011] Therefore, when connecting L-shaped connecting pipe bodies 50, 60, in order to reduce the overall pressure loss, it was necessary to use inlet port 24 formed in a straight line relative to flow path 23. As a result, it was necessary to prepare multiple types of universal joints 20, including universal joints 20 having bent connecting ports 24 and universal joints 20 having straight connecting ports 26, 28.

[0012] The present invention was created to solve the above-mentioned problems, and its object is to provide a universal joint for high-pressure piping that can be used compactly, has little pressure loss for high-pressure air, and can be used for a variety of applications with just one joint. [Means for solving the problem]

[0013] In order to achieve the above-mentioned object, the first means of the present invention is a universal joint for high-pressure piping comprising a pipe fitting 10 which is screwed onto a high-pressure piping on the equipment side to supply high-pressure air, a universal joint 20 which is rotatably inserted into the end of the pipe fitting 10 via an O-ring 22, has a straight flow path 23 therein and has an inlet 24 which is continuous with the end of the flow path 23 at a right angle, and a fixing clamp 30 which is attached to the connecting ends of the pipe fitting 10 and the universal joint 20 to fix the universal joint 20 so that it can rotate freely, and in this universal joint for high-pressure piping which screws onto a connecting pipe body 40 which supplies high-pressure air to the inlet 24 of the universal joint 20, the axial center portion of the inlet 24 in the universal joint 20 is formed so as to coincide with the axial center portion of the flow path 23.

[0014] The second means is that in the universal joint 20, a tapered surface 23A is formed extending from the flow path 23 toward the inlet 24, and high-pressure air is directly supplied to the tapered surface 23A from the inlet 24, which has a larger diameter than the diameter of the flow path 23.

[0015] The fixed clamp 30 of the third means comprises a separable clamp body 31 which fits onto the outer periphery of each of the flanges 11, 26 formed at the connecting end of the pipe joint 10 and the universal joint 20, and a fastener 32 which tightens the outer periphery of the clamp body 31 when fitted.

[0016] The fourth aspect is a manufacturing method for forming the universal joint 20 according to claim 1, comprising the steps of: a first step of drilling the flow passage 23 in the universal joint 20 with a cutting drill; A second step of drilling a preliminary hole 23B at the position of the inlet 24 using a cutting drill having the same diameter as the flow path 23; and a third step of drilling the inlet 24 along the preliminary hole 23B with a cutting drill, This is a method for manufacturing a universal joint, in which the axial center portion of the inlet 24 in the universal joint 20 is formed continuously to coincide with the axial center portion of the flow passage 23.

[0017] The fifth means is a manufacturing method in which a tapered surface 23A inclined from the flow path 23 toward the inlet 24 is extended and formed at the tip of the cutting drill in the first step and the second step. Effect of the Invention

[0018] According to the present invention, the central axis of the continuous side end of the inlet 24 is formed to coincide with the central axis of the continuous side end of the flow passage 23, so that the high-pressure air from the connecting pipe 40 is directly supplied to the side of the flow passage 23. Therefore, the length of the flow passage in the universal joint 20 becomes extremely short, and the contact distance of the compressed air, which loses pressure, also becomes extremely short.

[0019] Moreover, because the position of the axial center of the continuous side end of the inlet 24 coincides with the axial center of the continuous side end of the flow passage 23, there is no extra space that generates vortexes that cause pressure loss as in the past. Also, the tapered surface 23A formed on the flow passage 23 allows the high-pressure air supplied directly from the connecting pipe body 40 to be efficiently sent to the flow passage 23. As a result, it has become possible to greatly reduce pressure loss when high-pressure air is supplied from the connecting pipe body 40 to the universal joint 20. As a result, it is ideal for braking systems that use high-pressure air, such as vehicle braking systems.

[0020] In addition, because the pressure loss of the universal joint 20 is small, it is possible to select and connect not only a straight connecting pipe body but also a curved connecting pipe body 50 to the universal joint 20. As a result, it is possible to respond to a variety of situations and applications in which high-pressure piping is used.

[0021] Furthermore, the manufacturing method of the present invention, which includes steps 1 and 3, makes it possible to accurately and easily manufacture a universal joint that reduces pressure loss.

[0022] Thus, according to the present invention, there is a beneficial effect that the pressure loss of high pressure air in a vehicle braking system or the like is small, and it can be adapted to a variety of situations and applications. [Brief description of the drawings]

[0023] [Figure 1] 1 is a vertical cross-sectional view showing an embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view showing an embodiment of the present invention. [Diagram 3] FIG. 1 is an exploded perspective view showing an embodiment of the present invention. [Figure 4] 11(a) to 11(c) are process diagrams for continuously forming inlets in the flow passages of a universal joint. [Diagram 5] 2 is a cross-sectional view taken along line VV of FIG. 1. [Figure 6] FIG. 4 is a vertical cross-sectional view showing a continuous portion between a flow path and an inlet. [Figure 7] FIG. 11 is a perspective view showing another example of use of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention is a universal joint for connection to a high-pressure pipe. The main components of the present invention are a pipe joint 10, a universal joint 20, and a fixing clamp 30 (see FIG. 1).

[0025] The pipe fitting 10 is a joint member that is screwed to the end of a high-pressure pipe (see FIG. 2). The illustrated pipe fitting 10 is formed from a hexagonal bar material. That is, a flow path 12 is formed in the axial core of the hexagonal bar material. Furthermore, a male thread portion 13 is formed on the side that is screwed to the high-pressure pipe, and this male thread portion 13 is screwed to the end of the high-pressure pipe to connect the pipe fitting 10. Furthermore, a flange 11 is formed on the hexagonal head side of the hexagonal bar material (see FIG. 3).

[0026] The universal joint 20 is a member that is rotatably connected to the pipe joint 10, and has an inlet 24 formed therein that changes the direction of the flow path 23 that is aligned along the longitudinal direction of the pipe joint 10 at a right angle (see FIG. 1). This inlet 24 is formed so that its axis in the universal joint 20 coincides with the axis of the flow path 23 (see FIG. 6). The diameter of the inlet 24 is larger than the diameter of the flow path 23, and high-pressure air is directly supplied toward the side surface on the end side of the flow path 23 (see FIG. 5).

[0027] Further, a tapered surface 23A inclined toward the inlet 24 is formed at the end of the flow path 23 (see FIG. 1). In the illustrated example, the tapered surface 23A closer to the flow path 23 and the tapered surface 23A closer to the inlet 24 are formed at different angles. That is, the tapered surface 23A closer to the flow path 23 is formed by the tip of a drill that cuts the flow path 23, and the tapered surface 23A closer to the inlet 24 is formed by the tip of a drill that cuts the preliminary hole 23B at a right angle to the flow path 23 (see FIGS. 1 and 5).

[0028] Moreover, because the axis of flow passage 23 coincides with the axis of inlet 24, when high-pressure air is supplied from large-diameter inlet 24, the flow speed increases along tapered surface 23A of flow passage 23, and the high-pressure air is focused at tapered surface 23A and flows in the longitudinal direction of flow passage 23. At this time, it was found that the pressure loss caused by vortexes of the high-pressure air and contact parts is approximately half that of conventional universal joints. As a result, it is possible to connect a connecting pipe 40 that is connected to inlet 24 with a pre-bent shape (see Figure 1).

[0029] The illustrated universal joint 20 is formed integrally with a cylindrical insertion pipe 26 to be inserted into the end of the pipe joint 10 and a block-shaped connector 27 that forms the inlet 24 (see FIG. 3). A flange 21 is provided protruding from the insertion pipe 26.

[0030] An O-ring 22 is provided on this insertion pipe 26 (see FIG. 1). This O-ring 22 is a member that ensures airtightness when the pipe joint 10 and the insertion pipe 26 are connected. By setting the surface roughness (Ra=about 1.6) of the inner surface of the pipe joint 10 that comes into contact with the O-ring 22 and the inner surface of the storage groove 22A that stores the O-ring 22, leakage from the O-ring 22 is reliably prevented even with high-pressure air of about 1.35 MPa (see FIG. 3).

[0031] The inlet 24 formed on the side of the connector 27 has a female thread 25 formed on the inner surface (see FIG. 3). Any connecting pipe 40 is screwed to this female thread 25. This connecting pipe 40 may be straight or bent, and it is also possible to screw a hose-shaped connecting pipe 40 to this connecting pipe 40 (see FIG. 7).

[0032] The fixing clamp 30 is a fixing member that connects the pipe joint 10 and the universal joint 20 and firmly fixes them after adjusting the direction of the inlet 24 of the universal joint 20 so that it can rotate freely (see FIG. 2). The fixing clamp 30 is composed of a clamp body 31 and a fastener 32 (see FIG. 3).

[0033] The clamp body 31 is a connecting member that surrounds each of the flanges 11, 21 (see FIG. 3). A pair of semicircular clamp bodies 31 are used in combination to surround the entire circumference of each of the flanges 11, 21. Furthermore, a pair of fitting protrusions 31A that fit along the outer sides of each of the flanges 11, 21 is provided on the inner side of each of the clamp bodies 31.

[0034] On the other hand, fastener 32 is a fastening member attached to the outer periphery of each clamp body 31 (see FIG. 2). That is, fastener 32 is attached to the outer periphery of each clamp body 31 disposed along the entire periphery of flanges 11, 21. When each clamp body 31 is fastened with fastener 32, pipe joint 10 and universal joint 20 in a connected state are fixed (see FIG. 1).

[0035] The fastening device 32 includes a fastening band 32A that overlaps with the overlapping surface 31B of the clamp body 31, and an adjustment screw 32B that tightens the fastening band 32A (see FIG. 3). The adjustment screw 32B is provided at the open end of the fastening band 32A and is configured to tighten the fastening band 32A.

[0036] Therefore, by attaching clamp body 31 to flanges 11, 21 of pipe joint 10 and universal joint 20 and loosening tightening of fastener 32, the direction of the flow path of universal joint 20 can be rotatably adjusted. After the direction of the flow path of universal joint 20 has been determined, pipe joint 10 and universal joint 20 are fixed by firmly tightening adjustment screw 32B.

[0037] Next, a method for manufacturing the universal joint of the present invention will be described. This manufacturing process is particularly a process for forming the inlet 24 in the universal joint 20, and includes first to third steps (see FIG. 4).

[0038] The first step is to first cut a flow passage 23 along the longitudinal direction of the universal joint 20 with a cutting drill (see FIG. 4(a)). The second step is to cut a preliminary hole at the position of the inlet 24 with a cutting drill of the same diameter as the flow passage 23 (see FIG. 4(b)). The third step is to cut the inlet 24 with a cutting drill (see FIG. 4(c)). At this time, the central axis of the connecting end of the inlet 24 in the universal joint 20 is formed to coincide with the central axis of the connecting end of the flow passage 23 of the universal joint 20 (see FIG. 6). Then, a female thread portion 25 is formed around the inner periphery of the inlet 24.

[0039] Furthermore, the tip of the cutting drill used in the first and second steps is used to form the tapered surface 23A. That is, the first tapered surface 23A is formed at the tip of the cutting drill in the first step (see FIG. 4(A)). Next, a new tapered surface 23A continuing from the first tapered surface 23A is formed at the tip of the cutting drill in the second step (see FIG. 4(B)). Therefore, the tapered surface 23A has a different angle (see FIGS. 1 and 5).

[0040] When high-pressure air is supplied from inlet 24, which has a larger diameter than flow path 23, the flow speed increases at the center of inlet 24 where tapered surface 23A is located, and the surrounding high-pressure air is converged and flows in the longitudinal direction of flow path 23 (see FIG. 5). At this time, contact resistance between the high-pressure air and the flow path 23 and vortexes generated by the high-pressure air are greatly reduced. These effects combine to reduce the pressure loss of the high-pressure air in flow path 23.

[0041] If the pressure loss in the universal joint 20 is small, it becomes possible to use a combination of universal joints 20 (see FIG. 8). In the illustrated example, two universal joints of the present invention are connected together to a block manifold P.

[0042] The above-described configuration of the present invention is not limited to the embodiments. For example, the joint of the present invention can be used not only for high-pressure air supply equipment, but also as a piping joint for equipment in general industrial factories. [Explanation of symbols]

[0043] P Block Manifold 10. Pipe Fittings 11 Flange 12 Flow Path 13 Male thread 20 Universal joint 21 Flange 22 O-ring 22A Storage groove 23 Flow Path 23A Tapered surface 23B Spare hole 24 Inlet 25 Female thread 25 26 Insertion tube 27 Concatenation 30 Fixed clamp 31 Clamp body 31A Fitting protrusion 31B Polymerization surface 32 Fastening device 32A Tightening Band 32B Adjustment screw 40 Connecting pipe body

Claims

1. A pipe fitting that is screwed onto the high-pressure pipe on the equipment side to send high-pressure air, a universal joint which is rotatably inserted into an end of the pipe joint via an O-ring, has a linear flow passage therein and has an inlet which is continuous with the end of the flow passage at a right angle; A universal joint for high pressure piping is provided with a fixing clamp which is attached to connecting ends of a pipe joint and a universal joint to rotatably fix the universal joint, and a connecting pipe body which supplies high pressure air to an inlet of the universal joint is screwed in, A universal joint for high pressure piping, characterized in that an axial center portion of said inlet port in said universal joint is formed to be continuous with and coincide with an axial center portion of said flow passage.

2. A universal joint for high-pressure piping as described in claim 1, wherein a tapered surface inclined from the flow path toward the inlet is extended from the flow path, and high-pressure air is supplied directly to the tapered surface from the inlet, which has a diameter larger than the diameter of the flow path.

3. 2. A universal joint for high-pressure piping as claimed in claim 1, wherein the fixed clamp comprises a separable clamp body which fits onto the outer periphery of each flange formed at the connecting end of the pipe joint and the universal joint, and a fastener which tightens the outer periphery of the clamp body when fitted.

4. 2. A method of manufacturing a universal joint according to claim 1, comprising the steps of: a first step of drilling the flow passage in the universal joint with a cutting drill; A second step of drilling a preliminary hole at the position of the inlet using a cutting drill having the same diameter as the flow path; and a third step of drilling the inlet along the preliminary hole with a cutting drill, A method for manufacturing a universal joint for high pressure piping, comprising forming the inlet of the universal joint so that the axial center of the inlet coincides with the axial center of the flow passage.

5. 5. A method for manufacturing a universal joint for high pressure piping according to claim 4, wherein a tapered surface inclined from said flow passage toward said inlet is extended and formed at the tip of said cutting drill in said first step and said second step.

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