JPH03562Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention is useful when connecting a female member such as a bolt with a smaller diameter than the threaded hole of a female member such as an insert to a screw hole of a female member such as an insert. The present invention relates to a threaded joint suitable for use.

"Prior Art and its Problems" Conventionally, threaded joints have been used for the purpose of joining steel pipes in the axial direction, for example, as joints for straight pipe parts such as steel pipes. Such threaded joints, for example, cut a thread in the connection part with a pipe and connect them by screwing in, but with such threaded joints, corrosion occurs in the threads of the joint part. In some cases, the problem arises that the work of attaching and detaching them becomes troublesome.

As a means of solving this problem, the present applicants have proposed a threaded joint in which the above-mentioned type of joint is made of ceramics. However, simply replacing the conventional metal with ceramics for threaded joints would result in the failure of ceramics, which is brittle against tensile forces.
There are problems that need to be resolved, such as the difficulty of putting it into practical use.

"Means for Solving the Problem" Therefore, in the present invention, in a joint for connecting a male member having a male thread with a smaller diameter than the threaded hole of the female member to a threaded hole of the female member, the insertion hole of the male member is provided. a cylindrical joint body having a cylindrical shape and made entirely of a corrosion-resistant material such as ceramics; a male threaded portion formed on the outer periphery of the joint body and screwed into the screw hole;
and a female threaded portion formed on the back side of the insertion hole of the joint body and screwed into the male thread of the male member, and an insertion hole in which the male threaded portion of the joint body is formed with the female threaded portion of the joint body. It is characterized in that it is formed at a position farther away from the opening end of the insertion hole than from the inner side of the insertion hole.

Here, the male threaded portion and the female threaded portion of the joint body are formed by wrapping their respective screw-in side ends with each other, and the amount of overlap between the male threaded portion and the female threaded portion is equal to the number of threads of the female thread. If it is set in the range of ~5 or less threads, it is possible to improve resistance to lateral stress (hoop stress) generated in the lap portion between the female threaded portion and the male threaded portion.

"Operation" When a tensile load is applied to the female member screwed to the outer periphery of the joint body and the male member screwed to the inner periphery of the joint body, the joint body Since the inner side of the insertion hole and the outer periphery of the joint body are pulled in opposite directions from the open end of the insertion hole, inside the joint body, the inner and outer periphery of the joint body are pulled in the opposite directions. When the forces interact with each other, a shearing force is generated, and the tensile force that causes cracks and separations is almost never generated.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. This threaded joint 1 is for connecting two female members having different outer diameters. Insertion hole 3 for male member (bolt in the illustrated example) 2
A cylindrical joint body 4 having a
a male thread 7 formed on the outer periphery of the member and screwed into the screw hole 6 of the female member (such as an insert) 5; and a female thread formed at the back of the insertion hole 3 and screwed into the male thread 8 of the male member 2. The entire joint body 4 is made of a highly corrosion-resistant material such as ceramics or synthetic resin.

The insertion hole 3 extends along the central axis direction with only one end (left end in FIG. A female threaded portion 9 is formed.

Further, the external threaded portion 7 on the outer periphery of the joint body 4 is
It is formed at a position farther away from the opening end side of the insertion hole 3 (left side in Figure 1) than the part where the female threaded part 9 of the insertion hole 3 is formed (the part on the back side of the insertion hole 3). The lever joint main body 4 is designed so that shearing force is generated when a tensile force is applied to the outer circumferential portion and the inner circumferential portion.

Further, in the embodiment, the male threaded portion 7 and the female threaded portion 9 of the joint body 4 are formed by wrapping the threaded end portions 7a and 9a with each other, and the male threaded portion 7 and the female threaded portion As shown in FIG. 1, the lap length L with the portion 9 is set to 0 to 5 or less (3 in the embodiment) in terms of the number of threads of the female thread. When the number of threads is five or more, the male threaded portion 7 and the female threaded portion 9 are separated from each other at their respective ends 7a and 9.
a, a tensile force is generated locally in these lap portions, resulting in a decrease in yield strength. Also,
By wrapping the male threaded portion 7 and the female threaded portion 9, the resistance to lateral stress (hoop stress) generated in these threaded portions 7 and 9 is improved, and the strength of the joint body 4 is increased. It has the advantage of being able to

Next, the usage and operation of the threaded joint configured as described above will be explained.

To connect the male member 2 and the female member 5 using this threaded joint 1, the joint body 4 is screwed into the screw hole 6 of the female member 5, and the insertion hole 3 of this joint body 4 is
What is necessary is to insert the male member 2 into the hole and screw the male thread 8 into the female thread portion 9. Note that this connection procedure can also be performed by the reverse procedure of screwing the joint body 4 into the male member 2 and then screwing it into the screw hole 6 of the female member 2.

In the state connected in this way, the joint body 4
The male member 2 is inserted into the female threaded part 9 on the back side of the insertion hole 3.
Also, a female member 5 is attached to the male threaded portion 7 on the outer periphery of the joint member 4.
are in a screw-connected state, so when a tensile load is applied to the female member 5 and the male member 2, the inner peripheral part of the joint body 4 is exposed from the back side of the insertion hole 3 and the joint body At the outer periphery of 4, a tensile force is generated from the open end side of the insertion hole 3. Therefore, inside the joint body 4, the tensile forces of the inner and outer circumferences of the joint body 4 interact with each other to generate shearing force, and the tensile force that causes cracks and separation is almost eliminated. It never occurs. Therefore, even if the joint main body 4 is made of ceramics or the like which is brittle against tensile forces, it can exhibit a large yield strength and can be made lighter.

In addition, if the joint body 4 is made of a material with high corrosion resistance such as ceramics, corrosion of the threads at the joint part will not occur, and therefore, it will not be possible to prevent corrosion of metals etc. The applicability of threaded joints can be improved. In particular, when the joint body 4 is made of ceramics, there is an advantage that not only corrosion resistance can be improved, but also heat resistance and insulation properties can be improved.

FIG. 3 shows another embodiment of the invention. This threaded joint has a male threaded portion 7 on the outer periphery of the joint body 4.
and the female threaded portion 9 on the inner circumference, without wrapping the female threaded portion 9 to the back side of the insertion hole 3, and the male threaded portion 7.
are formed so as to be located on the open end side of the insertion hole 3, and even with such a configuration, substantially the same effects as in the previous embodiment can be expected.

In addition, in the above embodiment, an example was shown in which a bolt was used as the male member 2 and an insert was used as the female member 5, but in the present invention, these male member 2 and female member 5 are limited to the embodiment. For example, the male member 2 is used as a separator, and the female member 5 is used as a separator.
may be used as a cone, etc., and the shape of male and female members,
The structure etc. are arbitrary.

"Effects of the Invention" As explained above, the threaded joint of the present invention includes a cylindrical joint body which has an insertion hole for a male member and is entirely made of a corrosion-resistant material such as ceramics.
comprising a male threaded portion formed on the outer periphery of the joint body and screwed into the screw hole, and a female threaded portion formed on the back side of the insertion hole of the joint body and screwed into the male thread of the male member, In addition, by forming the male threaded portion of the joint body at a position farther away from the opening end of the insertion hole than the back side of the insertion hole where the female threaded portion of the joint body is formed, shearing force is mainly applied to the joint body. Since this is made to work, even if the joint body is made of a corrosion-resistant material such as ceramics, a large yield strength can be exhibited, and the applicability to ceramic threaded joints can be improved.

Here, the male threaded portion and the female threaded portion of the joint body are formed by wrapping their screw-in end portions together, and the amount of overlap between the male threaded portion and the female threaded portion is equal to the number of threads of the female thread. If it is set within the range of ~5 threads or less, it is possible to improve the resistance to the lateral stress (hoop stress) that occurs in the lap between the female thread and the male thread, and increase the yield strength of the threaded joint. can.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention. Figure 1 is a half-sectional view of a threaded joint, and Figure 2 is a threaded joint that connects a female member and a male member. FIG. 3 is a half sectional view showing another embodiment of the present invention. 1...Threaded joint, 2...Male member, 3...Insertion hole, 4...Joint body, 5...Female member, 6...Threaded hole, 7...Male thread, 8...Male thread, 9...Female thread, L...Lap allowance.

Claims (1)

[Claims for Utility Model Registration] 1. A joint for connecting a male member having a male thread with a smaller diameter than the threaded hole to a threaded hole in a female member, which has an insertion hole for the male member and the entire A cylindrical joint body made of a corrosion-resistant material such as ceramics, a male thread formed on the outer periphery of the joint body and screwed into the screw hole, and a male thread formed on the back side of the insertion hole of the joint body. and a female threaded portion that is screwed into the male thread of the male member, and the male threaded portion of the joint body is located closer to the open end of the insertion hole than to the back of the insertion hole in which the female threaded portion of the joint body is formed. A threaded joint characterized by being formed at separate locations. 2. The male threaded portion and the female threaded portion of the joint body are formed by wrapping their screw-in side ends with each other, and the lap allowance between the male threaded portion and the female threaded portion is 0 to 0 based on the number of threads of the female thread. The threaded joint according to claim 1 of the utility model registration claim, characterized in that the threaded joint has five threads or less.