JP2022169977A - Press caulking metal mold - Google Patents

Abstract

To air-tightly or fluid-tightly connect a press type pipe coupling and a piping element while reducing formation of an excess portion regardless of materials constituting the pipe coupling and the piping element.SOLUTION: A press caulking metal mold comprises a molding surface in which an annular groove part corresponding to an annular swollen part of a press type pipe coupling, and six flat pressing surfaces, which are so provided as to surround a reduced diameter part positioned on both sides or one side of the annular swollen part in an axial direction of the press type pipe coupling and face the reduced diameter part, are formed, and reduces a diameter of the reduced diameter part by pressing the reduced diameter part by the pressing surfaces. The press caulking metal mold is divided into two or three partial metal molds around an axis of the press type pipe coupling, and a recess defining a space, which extends to an outer side in a radial direction of the press type pipe coupling with respect to both or one of extension surfaces of adjacent pressing surfaces in respective partial metal molds, is provided between the afore-said adjacent pressing surfaces.SELECTED DRAWING: Figure 2

Description

The present invention relates to press caulking dies. More specifically, the present invention relates to a press-crimping die that can reliably connect a press-type pipe joint and a pipe element in an airtight or liquid-tight manner.

For example, in the construction of a piping system constructed by connecting thin-walled piping elements made of metal such as iron, including stainless steel, from the viewpoint of ensuring ease of work and safety, firearms, etc. It is common to use mechanical type fittings that do not require use. Mechanical type pipe joints are classified into various types such as press type, tube expansion type, nut type, rolling screw type, insertion type and coupling type according to the standard (SAS322) defined by the Stainless Steel Association.

According to the mechanical type pipe joint, the pipe elements are connected by inserting the end portion of the straight pipe as a pipe element into (the socket portion of) the pipe joint and deforming (caulking) the annular bulging portion. can be used to organize the piping system. A specific example of such a mechanical type pipe joint is a "press type pipe joint" disclosed in Patent Document 1 (Japanese Patent No. 3436822). In this press-type pipe joint, an annular sealing member (O-ring) made of an elastic material is mounted inside (annular groove) an annular bulging portion formed in the socket portion, and the end portion of the piping element (connecting pipe) is fitted. (pipe end) is inserted into the socket portion and the seal member. Then, while this state is maintained, the portions on both sides sandwiching the annular bulging portion in the axial direction of the socket portion and the annular bulging portion are diameter-reduced (crimped) by a press crimping die, and are directed inward in the radial direction ( centripetal direction) to connect the pipe joint and the pipe element in an air-tight or liquid-tight manner.

FIG. 13 is a schematic diagram showing how another piping element is connected to the press-type pipe joint integrally formed at the pipe end of the piping element. In the example shown in FIG. 13 , a socket portion 221 is integrally formed over a certain range at the pipe end of the pipe element 211 . An annular bulging portion 222 is formed integrally with the socket portion 221 , and an annular sealing member (not shown) is provided inside the annular bulging portion 222 . A press-type pipe joint 220 is composed of the socket portion 221, the annular swelling portion 222, and the sealing member.

When connecting the other piping element 212 and the press-type pipe joint 220, as indicated by the black arrows in the figure, the piping element is inserted into the socket portion 221 of the press-type pipe joint 220 and inside the sealing member (not shown). A tube end at 212 is inserted. Next, while this state is maintained, the portions on both sides sandwiching the annular bulging portion 222 in the axial direction of the annular bulging portion 222 and the socket portion 221 (see hatched portions 223 shown in the figure) are press-crimped (not shown). The piping element 212 and the press-type pipe joint 220 are connected in an airtight or liquid-tight manner by reducing the diameter (crimping) with a mold. In addition, on both sides of the annular bulging portion 222, diameter-reduced portions having a substantially hexagonal cross section (hereinafter sometimes referred to as “hexagonal cross-section diameter-reduced portions”) are formed. The occurrence of relative movement (eg, indexing and/or dislodgement, etc.) with the press fitting 220 is also reduced.

The hexagonal cross-section constricted portion has a hollow portion having a substantially hexagonal cross-section corresponding to the hexagonal cross-section constricted portion and has a plurality (typically two or three) of partial metal portions in the circumferential direction. A press crimping die divided into dies (partial dies) is moved radially inward to reduce the diameter of the socket (both or one of the portions on both sides sandwiching the annular bulging portion in the axial direction). It is formed. It is not possible to achieve uniform annular contraction of the annular bulge by radially inward (centripetal) movement from such a finite number of directions (eg, two or three). However, the portions on both sides (sometimes one side) sandwiching the annular bulging portion in the axial direction of the socket portion (hereinafter sometimes referred to as “reduced diameter portions”) have a substantially hexagonal cross section. The material forming the annular bulging portion is pulled by the diameter-reduced portion in the process of reducing the diameter. As a result, the annular bulging portion can be uniformly and annularly reduced in diameter.

Therefore, in order to reduce the diameter of the annular bulging portion uniformly and annularly, it is important to reduce the diameter of the portion to be reduced so that the shape of the cross section of the hexagonal cross-sectional diameter reduced portion is a regular hexagon as accurately as possible. is. By uniformly and annularly reducing the diameter of the annular bulging portion, the sealing member made of the annular elastic body contained in the annular bulging portion is also uniformly compressed, and the straight pipe portion of the piping element and the press type seal member are also uniformly compressed. The pipe joint can be connected in an airtight or liquid-tight manner. However, in reality, it is not easy to uniformly and annularly reduce the diameter of the annular bulging portion by reducing the diameter of the portion to be reduced so that the shape of the cross section of the hexagonal cross-section reduced diameter portion is an accurate regular hexagon. do not have. A case of forming a hexagonal cross-sectional diameter reduction portion using a press crimping die divided into two partial dies will be described below.

FIGS. 14, 15 and 16 (a) each show a press-type pipe formed using a conventional press crimping die (hereinafter sometimes simply referred to as "conventional crimping die"). FIG. 4 is a schematic diagram showing a diameter-reduced portion at the start of the process of connecting the joint and the piping element, at an intermediate stage of diameter reduction, and at the time when the diameter reduction is almost completed. Also, FIG. 16(b) is an enlarged view of a portion surrounded by a thick broken line in FIG. 16(a).

Three pressing surfaces 313a to 313c and three pressing surfaces 323a to 323c are formed on a pair of partial molds 310 and 320 that constitute the conventional caulking mold 300, respectively. As illustrated in FIG. 14, a socket portion 221 of a press type pipe joint 220 into which a pipe end of a pipe element 212 is inserted is installed in a space surrounded by these six pressing surfaces. At this time, so that an annular bulging portion (not shown) formed on the socket portion 221 fits into an annular groove (not shown) formed on the molding surfaces of the pair of partial molds 310 and 320, Partial molds 310 and 320 and press fitting 220 are arranged.

Then, as illustrated in FIGS. 15 and 16, by bringing the pair of partial molds 310 and 320 closer to each other, the three pressing surfaces 313a to 313c and the three pressing surfaces 323a to 323c respectively possessed by the molds 310 and 320 are used to press the inner surfaces in the radial direction. The outer peripheral surface of the socket portion 221 is pressed in the direction (centripetal direction). As a result, as shown in FIG. 16(a), a diameter-reduced portion having a substantially regular hexagonal cross-section (hexagonal cross-sectional diameter-reduced portion) is obtained. At this time, there are cases where the material does not conform to the shape of the corner portion between the two adjacent pressing surfaces, and the material cannot be completely accommodated in the cavity of the conventional crimping die. As a result, as exemplified in FIG. 16(b), a surplus (knob portion) may be formed on the mating surfaces of the pair of partial molds 310 and 320 (division surface of the caulking mold) (thick dashed line (see the part surrounded by ).

The surplus portion (knob portion) as described above may be formed not only at the hexagonal cross-sectional diameter reduction portion but also continuously from the hexagonal cross-sectional diameter reduction portion to the annular swelling portion. FIGS. 17 and 18 respectively show an intermediate stage of diameter reduction in the process of connecting the press-type pipe joint 220 and the piping element 212 using the conventional caulking die 300, and an annular bulge when the diameter reduction is almost completed. It is a schematic diagram which shows a part. As exemplified in FIGS. 17 and 18 , there are cases in which an extra portion (knob portion) is formed not only in the diameter-reduced portion of the press-type pipe joint 220 but also in the annular bulging portion.

In the above case, depending on the shape and/or size of the cross section (the cross section taken along the plane perpendicular to the longitudinal direction) of the extra portion (knob portion), the pipe inserted into the socket portion 221 of the press type pipe joint 220 may There is a gap not only between the element 212 and the extra portion (knob portion), but also between the annular sealing member (O-ring) 230 mounted inside (annular groove) of the annular swelling portion and the extra portion (knob portion). may occur (see the area enclosed by the thick dashed line). In this case, the gap may become a flow path (a bypass flow path in the axial direction) passing through the hexagonal cross-sectional diameter reduction portion, the annular bulging portion, and the hexagonal cross-sectional diameter reduction portion. 212 may be difficult to achieve. Therefore, in order to airtightly or liquid-tightly connect the press-type pipe joint and the piping element by reducing the diameter (crimping), the surplus portion (knob portion) must be ) is desirable to reduce the formation of

In addition, the problem described above is caused by the fact that, for example, when the coefficient of friction between the socket portion of the press type pipe joint and the molding surface of the mold is large, the socket portion slides smoothly along the molding surface of the press crimping mold. This is considered to be caused by the intensive plastic flow of the material forming the socket portion toward the parting surface of the press crimping die. That is, it is considered that the surplus portion (knob portion) is formed due to the phenomenon that the strain accompanying the molding of the hexagonal cross-sectional diameter reduction portion is finally concentrated in the vicinity of the dividing surface of the press crimping die.

As a means for absorbing strain due to deformation during caulking as described above, for example, in Patent Document 2 (Japanese Utility Model Registration No. 3052402), a metal pipe fitted on the joint is provided on the outer peripheral surface of the joint. It has been proposed to provide a plurality of relief portions (concave portions) in a crimping blade portion for pressing into an annular groove portion by crimping. According to this, since strain due to deformation can escape to the relief portion, the diameter reduction state in the portion other than the relief portion becomes appropriate, and an appropriate crimped state as a whole can be obtained. However, in this method, a part of the metal pipe is intentionally protruded at the relief portion in order to alleviate the distortion caused by deformation. A tight connection cannot be achieved reliably.

Furthermore, in Patent Document 3 (U.S. Patent Application Publication No. 2021/0008611), the molding surface of one partial mold is composed of three flat surfaces, and the molding surface of the other partial mold is a curved surface and a concave portion. A press caulking die configured by The concave portion of the other partial mold is considered to have a stopper function for "preventing rotation (indexing prevention)", and the diameter-reduced portion is formed so that the cross-sectional shape of the diameter-reduced portion is an accurate regular hexagon. Forming is not intended. In addition, the molding surface of one of the partial molds is composed of planes corresponding to three adjacent sides of a regular hexagon, similar to the partial molds constituting the conventional crimping mold described above. cannot solve the problems mentioned above.

Japanese Patent No. 3436822 Utility Model Registration No. 3052402 U.S. Patent Application Publication No. 2021/0008611

As described above, in this technical field, regardless of the materials that constitute the press type pipe joint and the piping element, it is possible to reduce the formation of the extra portion (knob portion) and accurately form the hexagonal cross-sectional diameter reduction portion. There is a demand for press crimping dies that can airtightly or liquidtightly connect a pipe joint and the pipe element.

Therefore, as a result of intensive research, the inventors of the present invention have found that by providing a concave portion having a space extending radially outward from the pressing surface between the adjacent pressing surfaces of the partial molds constituting the press crimping mold, We have found that the above problems can be solved.

Specifically, the press crimping die according to the present invention (hereinafter sometimes referred to as the "crimping die of the present invention") has a molding surface in which an annular groove and a pressing surface are formed. It is a press crimping die configured to reduce the diameter of a diameter-reduced portion of a type pipe joint by pressing the diameter-reduced portion with a pressing surface. The annular groove is an annular recess having a shape corresponding to the annular bulge of the press-type pipe joint. The diameter-reduced portion is a portion of the press-type pipe joint located on both sides or one side of the annular bulging portion in the axial direction of the press-type pipe joint. The pressing surfaces are six planes arranged around the axis of the press-type pipe joint so as to surround the diameter-reduced portion and facing the diameter-reduced portion.

The crimping die of the present invention is divided into two or three partial dies around the axis of the press type pipe joint. When the crimping die of the present invention is divided into two partial dies, each partial die has three pressing surfaces. When the crimping die of the present invention is divided into three partial dies, each partial die has two pressing surfaces.

Furthermore, in each of the partial molds, the corners, which are the portions between the adjacent pressing surfaces, are provided with two planes, i.e., virtual pressing surfaces obtained by extending the adjacent pressing surfaces, respectively. Also provided is a recess that defines a space that extends outward in the radial direction of the press-type pipe joint.

As described above, in each of the partial molds that constitute the crimping mold of the present invention, recesses defining spaces that extend outward in the radial direction of the press-type pipe joint from both or one of the imaginary pressing surfaces are adjacent to each other. It is provided at the corner portion between the pressing surfaces. Therefore, the contact area between the pressing surface and the diameter-reduced portion is reduced as compared with the conventional caulking mold. As a result, even when the coefficient of friction between the socket portion of the press-type pipe joint and the molding surface of the mold is large, the diameter-reduced portion can be smoothly slid along the pressing surface, and the parting surface of the mold can move smoothly. It is possible to reduce the amount of material that plastically flows intensively. That is, it is possible to reduce the occurrence of a phenomenon in which the strain associated with the diameter reduction of the diameter-reduced portion concentrates in the vicinity of the parting surface of the mold. In addition, since the space defined by the concave portion exists at the corner portion, the strain associated with the diameter reduction of the diameter-reduced portion can be relaxed in the concave portion as well. Therefore, according to the crimping die of the present invention, the press-type pipe joint and the piping element can be reliably connected in an airtight or liquid-tight manner by suppressing the formation of the excess portion (knob portion).

Other objects, features and attendant advantages of the present invention will be readily understood from the description of each embodiment of the present invention described with reference to the following drawings.

1 is a schematic front view illustrating the configuration of a press crimping die (first crimping die) according to a first embodiment of the present invention; FIG. FIG. 2 is a schematic perspective view showing an example of the configuration of two partial molds that constitute the first caulking mold illustrated in FIG. 1(a). FIG. 3 is a schematic plan view when the two partial molds illustrated in FIG. 2 are observed from the dividing surface side; A schematic side view (a) of the first crimping die illustrated in (a) of FIG. 1 and a schematic cross-sectional view ( b). FIG. 4 is a schematic diagram showing the profile of a cross-section of the partial mold 120 illustrated in FIG.

FIG. 10 is a schematic diagram showing a diameter-reduced portion at the start of the process of connecting the press-type pipe joint and the piping element using the first crimping die; FIG. 4 is a schematic diagram showing a portion to be diameter-reduced in the process of connecting the press-type pipe joint and the piping element using the first crimping die, in the course of diameter reduction. FIG. 4 is a schematic diagram showing a portion to be diameter-reduced when diameter reduction is almost completed in the process of connecting the press-type pipe joint and the piping element using the first crimping die. FIG. 10 is a schematic diagram showing the annular bulging portion at the time when diameter reduction is almost completed in the process of connecting the press-type pipe joint and the piping element using the first crimping die;

Schematic perspective view (a) illustrating the configuration of one partial mold of a pair of partial molds constituting a press crimping mold (second crimping mold) according to a second embodiment of the present invention; It is a schematic plan view (b) when the partial mold illustrated in (a) is observed from the dividing surface side. A schematic front view (a) of a partial mold that constitutes a press crimping mold (third crimping mold) according to the third embodiment of the present invention, and a schematic cross-sectional view of a portion where a pressing surface is formed ( b), and a schematic cross-sectional view (c) of a portion provided with a recess. Schematic front views (a) and (a) of one partial mold of a pair of partial molds constituting a press crimping mold (fifth crimping mold) according to the fifth embodiment of the present invention. Schematic cross-sectional view (b) of the portion of the illustrated partial mold where the pressing surface is formed, and a schematic plan view of the partial mold illustrated in (a) and (b) when observed from the split surface side (c). FIG. 4 is a schematic diagram showing how another piping element is connected to a press-type pipe joint integrally formed at the pipe end of the piping element.

FIG. 5 is a schematic diagram showing a diameter-reduced portion at the start of a process of connecting a press-type pipe joint and a piping element using a conventional press crimping die (conventional crimping die). FIG. 4 is a schematic diagram showing a portion to be diameter-reduced in the process of connecting a press-type pipe joint and a piping element using a conventional caulking die; FIG. 10 is a schematic diagram showing a portion to be diameter-reduced when diameter reduction is almost completed in the process of connecting a press-type pipe joint and a piping element using a conventional crimping die. FIG. 4 is a schematic diagram showing an annular bulging portion in the process of connecting a press-type pipe joint and a pipe element using a conventional caulking die, in the middle of diameter reduction. FIG. 10 is a schematic diagram showing an annular bulging portion at the time when diameter reduction is almost completed in the process of connecting a press-type pipe joint and a piping element using a conventional crimping die.

<<1st Embodiment>>
A press crimping die (hereinafter sometimes referred to as a "first crimping die") according to a first embodiment of the present invention will be described below with reference to the drawings.

<Constitution>
The first crimping die has a molding surface on which an annular groove and a pressing surface are formed, and is configured to press the diameter-reduced portion of the press-type pipe joint by the pressing surface to reduce the diameter of the diameter-reduced portion. It is a press caulking mold that has been designed. The annular groove is an annular recess having a shape corresponding to the annular bulge of the press-type pipe joint. The diameter-reduced portion is a portion of the press-type pipe joint located on both sides or one side of the annular bulging portion in the axial direction of the press-type pipe joint. The pressing surfaces are six planes arranged around the axis of the press-type pipe joint so as to surround the diameter-reduced portion and facing the diameter-reduced portion.

The first caulking die is divided into two or three partial dies around the axis of the press type pipe joint. When the first caulking die is divided into two partial dies, each partial die has three pressing surfaces. When the first caulking die is divided into three partial dies, each partial die has two pressing surfaces.

Furthermore, in each of the partial molds, the corners, which are the portions between the adjacent pressing surfaces, are provided with two planes, i.e., virtual pressing surfaces obtained by extending the adjacent pressing surfaces, respectively. Also provided is a recess that defines a space that extends outward in the radial direction of the press-type pipe joint.

FIG. 1 is a schematic front view illustrating the configuration of a first crimping die. A first caulking die 101a illustrated in (a) is divided into two partial dies 110 and 120. FIG. The partial mold 110 has three pressing surfaces 113a, 113b and 113c, and the partial mold 120 has three pressing surfaces 123a, 123b and 123c. The first caulking die 101b illustrated in (b) is divided into three partial dies 110 to 130. FIG. The partial mold 110 has two pressing surfaces 113a and 113b, the partial mold 120 has two pressing surfaces 123a and 123b, and the partial mold 130 has two pressing surfaces 133a and 133b. In the following description, the first crimping die 101a divided into two partial dies 110 and 120 will be described. However, the first crimping die 101b divided into three partial dies 110 to 130 also differs in the number of partial dies and the number of pressing surfaces each of the partial dies has. It is the same as the mold 101a.

FIG. 2 is a schematic perspective view showing an example of the configuration of two partial molds 110 and 120 that constitute the first crimping mold 101a illustrated in FIG. 1(a). However, the partial mold 110 illustrated in (a) of FIG. 2 rotates the partial mold 110 clockwise by 180° so that the divided surface of the partial mold 110 illustrated in (a) of FIG. 1 faces upward. It is in a state where FIG. 3 is a schematic plan view of the two partial molds 110 and 120 illustrated in FIG. 2 as viewed from the dividing surface side. 2 and 3, the partial mold 110 is shown in (a) and the partial mold 120 is shown in (b). Furthermore, FIG. 4 is a schematic side view (a) of the first crimping die 101a illustrated in (a) of FIG. 101a is a schematic cross-sectional view (b).

An annular groove 112 and three pressing surfaces 113a, 113b and 113c are formed on the molding surface 111 of the partial mold 110 illustrated in FIGS. 2 and 3 (a) and FIG. 4 (b). . The molding surface 111 is the surface of the partial mold 110 on the side (inner side) facing the press type pipe joint (not shown) to be crimped by the first crimping mold 101a. The annular groove portion 112 is an annular depression having a shape corresponding to the annular bulge portion of the press type pipe joint. The pressing surfaces 113a, 113b, and 113c are arranged around the axis of the press-type pipe joint while facing each of the diameter-reduced portions located on both sides of the annular bulging portion in the axial direction of the press-type pipe joint. are three planes provided in the That is, in the partial mold 110 constituting the first crimping mold 101a, a pair of pressing surfaces 113a, a pair of 113b and a pair of 113c ( That is, a total of six pressing surfaces are provided.

2 and 3(b) and FIG. 4(b) has an annular groove 122 and three pressing surfaces 123a, 123b and 123c. is formed. The molding surface 121 is the surface of the partial mold 120 on the side (inner side) facing the press type pipe joint (not shown) to be crimped by the first crimping mold 101a. The annular groove portion 122 is an annular depression having a shape corresponding to the annular bulge portion of the press type pipe joint. The pressing surfaces 123a, 123b, and 123c are arranged around the axis of the press-type pipe joint while facing each of the diameter-reduced portions located on both sides of the annular bulging portion in the axial direction of the press-type pipe joint. are three planes provided in the That is, in the partial mold 120 that constitutes the first crimping mold 101a, a pair of pressing surfaces 123a, a pair of 123b, and a pair of 123c ( That is, a total of six pressing surfaces are provided.

As a result, the first mold 101a composed of the two partial molds 110 and 120 as described above has an annular groove, which is an annular depression having a shape corresponding to the annular bulge of a press type pipe joint, It is disposed around the axis of the press-type pipe joint so as to surround the diameter-reduced portions, which are portions of the press-type pipe joint located on both sides of the annular bulging portion in the axial direction of the press-type pipe joint, and is attached to the diameter-reduced portion. A pressing surface, which is six opposing planes, and a molding surface on which are formed. As long as the positional relationship between the press-type pipe joint and the piping element (not shown) is sufficiently fixed and it is possible to connect the press-type pipe joint in an airtight or liquid-tight manner, the axial direction of the press-type pipe joint does not necessarily have to be annular. It is not necessary to provide the diameter-reduced portions on both sides of the bulging portion, and the diameter-reducing portion may be provided only on one side of the annular bulging portion.

The first crimping die 101a is configured to reduce the diameter of the diameter-reduced portion by pressing the diameter-reduced portion with six pressing surfaces 113a to 113c and 123a to 123c. Specifically, the socket portion of the press-type pipe joint into which the pipe end of the pipe element is inserted is installed in the space surrounded by these six pressing surfaces. At this time, the partial molds 110 and 120 are arranged so that the annular bulge formed in the socket fits into the annular grooves 112 and 122 formed in the molding surfaces 111 and 121 of the pair of partial molds 110 and 120, respectively. 120 and press fittings are arranged. Then, by bringing the pair of partial molds 110 and 120 closer to each other by a driving device (for example, a press machine) (not shown), the three pressing surfaces 113a to 113c and the three pressing surfaces 123a to 123c are directed radially inward ( centripetal direction). As a result, the portion to be reduced in diameter is reduced in diameter so that the shape of the cross section approaches a regular hexagon, and the aforementioned hexagonal cross-sectional diameter reduction portion is formed.

At this time, as described above, in the conventional press crimping mold (conventional crimping mold), the material does not conform to the shape of the corner portion between the two adjacent pressing surfaces, and the cavity of the conventional crimping mold The material may not fit inside. As a result, an extra portion (knob portion) may be formed on the dividing surfaces of the pair of partial molds. By forming such a surplus portion (knob portion), an annular seal member is mounted not only between the pipe element and the surplus portion (knob portion) in the hexagonal cross-sectional diameter reduction portion but also inside the annular bulging portion (annular groove). A gap may also occur between the (O-ring) and the extra portion (knob portion). In this case, the gap may become a flow path (axial bypass flow path) passing through the hexagonal cross-sectional diameter reduction portion, the annular bulging portion, and the hexagonal cross-sectional diameter reduction portion. It may be difficult to achieve an airtight or liquid-tight connection between the two.

However, in the two partial molds 110 and 120 that constitute the first crimping mold 101a, recesses are provided at the corners between the adjacent pressing surfaces. Specifically, as illustrated in FIGS. 3 and 4B, in the partial mold 110, the recess 114a is provided between the adjacent pressing surfaces 113a and the adjacent pressing surfaces 113b. and the pressing surface 113c are provided with recesses 114b. On the other hand, in the partial mold 120, a concave portion 124a is provided between adjacent pressing surfaces 123a and 123a, and a concave portion 124b is provided between adjacent pressing surfaces 123b and 123c. .

As described above, the recess is a space that extends outward in the radial direction of the press-type pipe joint from both or one of the imaginary pressing surfaces, which are two planes obtained by extending the adjacent pressing surfaces. is a recess that defines the In other words, in a vertical projection onto a plane perpendicular to the axis of the press fitting, the space defined by the recesses (the recesses formed in the molding surface) is defined by six straight lines passing through the six pressing surfaces respectively. extends outside the bounding hexagon.

FIG. 5 is a schematic diagram showing the profile of a cross section along a plane including the axis of the press type pipe joint represented by line AA of the partial mold 120 illustrated in FIG. 3(b). In FIG. 5, the line Ca-Ca represents a virtual plane (virtual pressing surface Pa) obtained by extending the pressing surface 123a, and the line Cb-Cb represents a virtual plane obtained by extending the pressing surface 123b. A plane (virtual pressing surface Pb) is represented, and a line Cc-Cc represents a virtual plane (virtual pressing surface Pc) obtained by extending the pressing surface 123c. A recess 124a is provided at a corner portion between the pressing surface 123a and the pressing surface 123b. ) extends to the outside in the radial direction. Similarly, a recess 124b is provided at a corner portion between the pressing surface 123b and the pressing surface 123c, and the recess 124b is more likely than at least one of the imaginary pressing surface Pb and the imaginary pressing surface Pc. (not shown) in the radial direction.

Although not shown, a cross section along a plane represented by a line A′-A′ located on the opposite side of the line AA across the annular groove 122 of the partial mold 120 illustrated in FIG. 3B is also shown. Same as above. Also, although not shown, the other partial mold 110 is similar to the above.

In addition, the configuration (for example, shape, size, etc.) of the concave portion is determined by, for example, the mechanical strength and hardness of the material constituting the press type pipe joint and the pipe element, the coefficient of friction with the molding surface of the first crimping mold, and plasticity. Depending on various factors such as processing characteristics, it can be appropriately determined so that the desired effect of suppressing the excess portion (knob portion) is achieved. In addition, the space defined by the recess does not necessarily extend to the outer side in the radial direction of the press type pipe joint from both or one of the imaginary pressing surfaces of the adjacent pressing surfaces in the entire corner. That is, the space defined by the recess may include a portion that remains radially inward of the press-type pipe joint relative to any imaginary pressing surface.

Here, a case of forming a hexagonal cross-sectional diameter reduced portion by reducing the diameter of the portion to be reduced using the first crimping die 101a will be described.

6, (a) of FIG. 7 and FIG. 8 respectively show the starting point of the process of connecting the press-type pipe joint and the piping element using the first crimping die 101a, the middle stage of diameter reduction, and the FIG. 4 is a schematic diagram showing a portion to be diameter-reduced when the diameter is almost completed; 7(b) is an enlarged view of a portion surrounded by a thick broken line in FIG. 7(a). For the sake of space in the drawings, reference numerals for the pressing surface and the recess are omitted in FIGS. 7 and 8. FIG.

As illustrated in FIG. 6, three pressing surfaces 113a to 113c and three pressing surfaces 123a to 123c are formed on a pair of partial molds 110 and 120 that constitute the first crimping mold 101a. A socket portion 221 of a press type pipe joint 220 into which the pipe end of the pipe element 210 is inserted is installed in a space surrounded by these six pressing surfaces. At this time, as described above, the annular bulging portion (not shown) formed on the socket portion 221 is fitted into the annular groove portion (not shown) formed on the molding surfaces of the pair of partial molds 110 and 120. The partial molds 110 and 120 and the press type pipe joint 220 are arranged so as to do so.

Then, the pair of partial molds 110 and 120 are brought close to each other as indicated by white arrows in FIG. 7(a). As a result, the outer peripheral surface of the socket portion 221 is pressed radially inward (centripetal direction) by the three pressing surfaces 113a to 113c and the three pressing surfaces 123a to 123c.

At this time, in the press crimping die according to the conventional technology (conventional crimping die), as described above, when the coefficient of friction between the socket portion of the press type pipe joint and the molding surface of the die is large, The socket portion cannot slide smoothly along the molding surface of the press crimping die. For this reason, the material forming the socket part undergoes intensive plastic flow toward the parting surface of the press crimping die, and the strain accompanying the molding of the hexagonal cross-sectional diameter reduction part finally affects the parting surface of the press crimping die. concentrate in the vicinity. As a result, a surplus portion (knob portion) tends to be formed on the mating surfaces of the pair of partial dies (partial surfaces of the caulking dies).

However, in the first crimping die 101a, recesses 114a, 114b, 124a, and 114b are provided at corners between adjacent pressing surfaces in each of the partial dies, as illustrated in FIG. there is Therefore, in the first crimping die 101a, the total area of the pressing surfaces is smaller than that of the conventional crimping die. As a result, as indicated by the black double-headed arrow in FIG. It is possible to smoothly slide the diameter portion and reduce the material that plastically flows intensively toward the parting surface of the mold. That is, it is possible to reduce the occurrence of a phenomenon in which the strain associated with the diameter reduction of the diameter-reduced portion concentrates in the vicinity of the parting surface of the mold. In addition, since the spaces defined by the recesses (114a, etc.) exist at the corners, the distortion associated with the diameter reduction of the diameter-reduced portion can be relaxed in the recesses as well.

Due to the above effects, according to the first crimping die 101a, the formation of excess portions (knob portions) is reduced regardless of the materials constituting the press-type pipe joint and the piping element, and as illustrated in FIG. A constricted portion having a substantially hexagonal cross section with high symmetry (hexagonal constricted cross-sectional constricted portion) can be formed, like a six-petaled flower.

FIG. 9 is a schematic diagram showing an annular bulging portion at an intermediate stage of diameter reduction in the process of connecting the press-type pipe joint and the piping element using the first crimping die 101a and at a time when the diameter reduction is almost completed ( It is an enlarged view (b) of a portion surrounded by a thick broken line in a) and (a). As described above, in the process of reducing the diameter of the diameter-reduced portion to be the diameter-reduced portion having a substantially hexagonal cross section (hexagonal cross-section diameter-reduced portion), the material forming the annular bulging portion is pulled by the diameter-reduced portion. be done. On the other hand, as described above, according to the first crimping fitting 101a, it is possible to form a highly symmetrical hexagonal cross-sectional diameter reduction portion while reducing the formation of the surplus portion (knob portion). As a result, as illustrated in FIG. 9, the annular bulging portion can be uniformly and annularly reduced in diameter. That is, according to the first crimping die 101a, the press-type pipe joint and the piping element can be reliably connected in an airtight or liquid-tight manner.

<effect>
As described above, in each of the partial molds that constitute the first crimping mold, there is a concave portion that defines a space extending outward in the radial direction of the press-type pipe joint from either or both of the imaginary pressing surfaces. It is provided at a corner that is a portion between adjacent pressing surfaces. Therefore, the contact area between the pressing surface and the diameter-reduced portion is reduced as compared with the conventional caulking mold. As a result, even when the coefficient of friction between the socket portion of the press-type pipe joint and the molding surface of the mold is large, the diameter-reduced portion can be smoothly slid along the pressing surface, and the parting surface of the mold can move smoothly. It is possible to reduce the amount of material that plastically flows intensively. That is, it is possible to reduce the occurrence of a phenomenon in which the strain associated with the diameter reduction of the diameter-reduced portion concentrates in the vicinity of the parting surface of the mold. In addition, since the space defined by the concave portion exists at the corner portion, the strain associated with the diameter reduction of the diameter-reduced portion can be relaxed in the concave portion as well. Therefore, according to the first crimping die, the press-type pipe joint and the piping element can be reliably connected in an airtight or liquid-tight manner by suppressing the formation of the excess portion (knob portion).

<<Second embodiment>>
A press crimping die (hereinafter sometimes referred to as a "second crimping die") according to a second embodiment of the present invention will be described below with reference to the drawings.

As described above, in each of the partial molds that constitute the first crimping mold, the recesses provided between the adjacent pressing surfaces reduce the contact area between the molding surface and the diameter-reduced portion, By dispersing and/or relieving the strain associated with the diameter reduction of the diameter portion, it is possible to suppress the formation of a surplus portion (knob portion) and to reliably connect the press-type pipe joint and the piping element in an air-tight or liquid-tight manner. . From the viewpoint of suppressing the formation of a surplus portion (knob portion) on the mating surface of the partial mold (the dividing surface of the caulking mold), it is necessary to prevent the forming surface and the diameter to be reduced not only between the adjacent pressing surfaces but also in the vicinity of the dividing surface. It is desirable to reduce the contact area with the portion and to distribute and/or relieve the strain associated with diameter reduction of the portion to be reduced.

<Constitution>
Therefore, the second crimping die is the above-described first crimping die, and is provided with inclined portions at both ends in the axial direction of the press-type pipe joint at both ends in the circumferential direction of the molding surface of the partial mold. It is a press caulking die characterized by being The inclined portion is a portion that is inclined away from the axis of the press-type pipe joint toward the end in the axial direction of the press-type pipe joint.

10A and 10B are schematic perspective views illustrating the configuration of a partial mold 110, which is one of a pair of partial molds constituting the second caulking mold 102. It is a schematic plan view (b) when 110 is observed from the dividing surface side. (a) and (b) of FIG. 10 respectively correspond to (a) of FIG. 2 and (a) of FIG.

As illustrated in FIG. 10(a), both ends in the axial direction of the press-type pipe joint at both ends in the circumferential direction of the molding surface 111 of the partial mold 110 constituting the second crimping mold 102 (that is, molding The four corners of the surface 111 are provided with inclined portions 115 (see the portion surrounded by the thick dashed line). Also, as illustrated in FIG. 10B, the inclined portion 115 is a portion that is inclined away from the axis AX of the press-type pipe joint toward the end in the direction of the axis AX of the press-type pipe joint. . As illustrated in FIG. 10(b), in the vertical projection view of the second crimping die 102 on the dividing plane, the inclined portion 115 is inclined at an angle θ with respect to the press-type pipe joint axis AX. .

The configuration of the inclined portion (for example, the shape, size, inclination angle with respect to the axis of the press-type pipe joint, etc.) is determined by, for example, the mechanical strength and hardness of the materials constituting the press-type pipe joint and the piping element, and the second caulking. Depending on various factors such as the coefficient of friction with the molding surface of the mold and plastic working characteristics, it can be appropriately determined so that the desired effect of suppressing the excess portion (knob portion) is achieved. For example, as long as the above requirements are met, the inclined portion may be configured with a flat surface or with a curved surface. Furthermore, the inclined portion may be configured by a combination of flat surfaces and/or curved surfaces. Also, although not shown, the inclined portion provided on the molding surface 121 of the other partial mold 120 is similar to the above.

<effect>
As described above, in each of the partial molds that constitute the second crimping mold, inclined portions are provided at both ends in the axial direction of the press-type pipe joint at both ends in the circumferential direction of the molding surface. . The inclined portion is inclined away from the axis of the press-type pipe joint toward the axial end of the press-type pipe joint. Therefore, in the second crimping die, the contact area between the forming surface and the diameter-reduced portion is reduced not only between the adjacent pressing surfaces but also in the vicinity of the dividing surface, and the strain associated with the diameter reduction of the diameter-reduced portion is reduced. can be dispersed and/or mitigated. As a result, according to the second crimping die, it is possible to effectively suppress the formation of the surplus portion (knob portion) on the mating surface of the partial dies (the dividing surface of the crimping die), and the press type pipe joint and the piping element can be separated. can be connected more reliably in an air-tight or liquid-tight manner.

1 to 3 referred to in the description of the first caulking die 101a described above also depict the inclined section, but the inclined section is not an essential component in the first caulking die.

<<Third embodiment>>
A press crimping die (hereinafter sometimes referred to as a "third crimping die") according to a third embodiment of the present invention will be described below with reference to the drawings.

As described above, in each of the partial molds that constitute the first crimping mold and the second crimping mold, the contact area between the molding surface and the diameter-reduced portion is reduced by the concave portion provided between the adjacent pressing surfaces. and dispersing and/or alleviating the strain associated with the reduction in diameter of the diameter-reduced portion suppresses the formation of a surplus portion (knob portion) and ensures airtightness or liquidtightness between the press-type pipe joint and the piping element. can be connected to

On the other hand, as noted above, it is not possible to uniformly and annularly contract the annular bulge by radially inward (centripetal) movement from a finite number of directions (e.g., two or three). be. However, the diameter-reduced portions located on both sides or one side of the press-type pipe joint sandwiching the annular bulging portion in the axial direction are pressed by the six pressing surfaces so that the diameter-reduced portions have a substantially hexagonal cross section. In the process of diameter reduction, the material forming the annular bulging portion is pulled by the diameter-reduced portion. As a result, the annular bulging portion can be uniformly and annularly reduced in diameter.

However, if the proportion of the concave portion on the forming surface is excessively large, the proportion of the portion pressed by the pressing surface on the forming surface will decrease, and the material that forms the annular bulging portion in the process of reducing the diameter of the portion to be reduced. is difficult to be pulled by the diameter-reduced portion. As a result, it may be difficult to uniformly and annularly reduce the diameter of the annular bulging portion. In particular, for example, if the recess is too long in the axial direction of the press-type pipe joint and too deep in the vicinity of the annular groove, the above problem becomes more pronounced.

In the above case, in the process of reducing the diameter of the diameter-reduced portion on the forming surface between the concave portion and the annular groove portion in the axial direction of the press-fitting pipe joint, the press-fitting pipe contacting the press-fitting pipe joint sufficiently. There may be few or no parts that can be pressed against. In addition, since the molding surface excluding the vicinity of the annular groove portion is divided in the circumferential direction (direction around the axis) by the concave portion, the stress that pulls the material forming the annular bulging portion in the process of reducing the diameter of the portion to be reduced is mainly the axial stress. It is possible that it only works in one direction. As a result, there is a high possibility that it will be difficult to uniformly and annularly reduce the diameter of the annular bulging portion.

<Constitution>
Therefore, the third crimping die is the first crimping die or the second crimping die described above, and is provided with a gradually changing portion at the axially inner end of the press-type pipe joint of the recess. It is a press caulking die characterized by The gradually changing portion is a portion in which the depth of the recess in the radial direction of the press-type pipe joint becomes shallower toward the inner side in the axial direction of the press-type pipe joint.

FIG. 11 shows a schematic front view (a) of a partial mold 120 that constitutes the third caulking mold 103, a schematic cross-sectional view (b) of a portion where a pressing surface 123c is formed, and a recess 124a. It is a schematic cross-sectional view (c) of the cut portion. As illustrated in (a) of FIG. 11 , in the partial mold 120 that constitutes the third crimping mold 103 as well as the partial mold 120 that constitutes the first crimping mold 101a described above, three presses are applied. Surfaces 123a, 123b and 123c are formed on the molding surface 121. A recess 124a is formed between adjacent pressing surfaces 123a and 123a, and a recess 124b is formed between adjacent pressing surfaces 123b and 123c. are provided respectively.

(b) of FIG. 11 is a schematic cross-sectional view along a plane including the axis of the press-type pipe joint represented by line DD of the partial mold 120 illustrated in (a), which is clear from (a). 3 is a schematic cross-sectional view of a portion of the partial mold 120 where the pressing surface 123c is formed as shown in FIG. Pressing surfaces 123c are formed on both sides in the axial direction (double arrow of broken line) of the annular groove portion 122 fitted to the annular swelling portion of the press-type pipe joint (not shown). Although not shown, the portion of the partial mold 120 where the pressing surface 123b is formed and the portion where the pressing surface 123a is formed are the same as above. Also, although not shown, the other partial mold 110 is similar to the above.

(c) of FIG. 11 is a schematic cross-sectional view along a plane including the axis of the press type pipe joint represented by line EE of the partial mold 120 illustrated in (a), which is clear from (a). 3 is a schematic cross-sectional view of the portion of the partial mold 120 provided with the concave portion 124a, as shown in FIG. Recesses 124a are formed on both sides in the axial direction (double arrow of broken line) of an annular groove 122 that fits into an annular bulge of a press-type pipe joint (not shown). Furthermore, at the inner end of the recess 124a in the axial direction of the press-type pipe joint, the depth of the recess 124a becomes shallower toward the inside (see the portion surrounded by the thick broken line). That is, a gradually changing portion is provided at the inner end portion of the recess 124a. Although not shown, the same applies to the portion of the partial mold 120 where the concave portion 124b is provided. Also, although not shown, the other partial mold 110 is similar to the above.

The configuration of the gradually changing portion (for example, the pattern of change in shape, size, depth, etc.) depends on, for example, the mechanical strength and hardness of the materials constituting the press type pipe joint and the piping element, and the strength of the third caulking mold. Depending on various factors such as the coefficient of friction with the molding surface and plastic working characteristics, it can be appropriately determined so that the desired effect of suppressing the excess portion (knob portion) is achieved. For example, the gradually changing portion may be configured with a flat surface or a curved surface as long as the above requirements are satisfied. Furthermore, the gradually changing portion may be configured by a combination of flat surfaces and/or curved surfaces.

<effect>
As described above, in the third crimping die, the gradually changing portion is provided at the axially inner end of the press-type pipe joint of the recess, and the depth of the press-type pipe joint of the recess in the radial direction is provided. The depth becomes shallower toward the inner side in the axial direction of the press-type pipe joint. By providing the gradually changing portion at the inner end portion of the recess in this way, the portion near the inner end portion of the recessed portion is increased in the process of reducing the diameter of the portion to be reduced, compared to the case where the gradually changing portion is not provided. It is possible to increase the possibility of contacting the press-type pipe joint and pressing the press-type pipe joint. In addition, in the process of reducing the diameter of the diameter-reduced portion, the part near the inner end of the recess comes into contact with the press-type pipe joint, thereby reducing the degree of division of the molding surface by the recess. As a result, the stress that pulls the material forming the annular bulging portion in the process of reducing the diameter of the diameter-reduced portion acts more uniformly over the entire circumference of the annular groove portion, and the annular bulging portion becomes more uniform and annular. diameter can be reduced.

1 to 4 and 10 referred to in the description of the first crimping die 101a and the second crimping metal fitting 102 described above also depict gradually changing portions, but the first crimping die and the second crimping metal In metal fittings, the gradual change portion is not an essential component.

<<Fourth embodiment>>
A press crimping die (hereinafter sometimes referred to as a "fourth crimping die") according to a fourth embodiment of the present invention will be described below.

As described above, in each of the partial molds that constitute the first to third crimping dies, the contact area between the molding surface and the diameter-reduced portion is reduced by the concave portion provided between the adjacent pressing surfaces. and dispersing and/or alleviating the strain associated with the reduction in diameter of the diameter-reduced portion suppresses the formation of a surplus portion (knob portion) and ensures airtightness or liquidtightness between the press-type pipe joint and the piping element. can be connected to From the viewpoint of further suppressing the formation of a surplus portion (knob portion) on the mating surface of the partial mold (parting surface of the caulking mold), it is desirable to reduce the coefficient of friction between the molding surface and the diameter-reduced portion. Specific means for reducing the coefficient of friction between the molding surface and the diameter-reduced portion include, for example, forming a film on the molding surface that exhibits a low coefficient of friction with respect to the material forming the diameter-reduced portion. can be mentioned.

<Constitution>
Therefore, the fourth crimping mold is any one of the first to third crimping molds described above, and is characterized in that a titanium carbonitride layer is formed on at least a part of the molding surface. It is a press caulking die. Titanium carbonitride (TiCN) layer is a ceramic coating with high hardness, low coefficient of friction and strong adhesion. can be reduced.

The titanium carbonitride (TiCN) layer may be formed on the entire molding surface of the partial mold forming the fourth caulking mold, or may be formed only on a part of the molding surface (for example, the pressing surface). may be The technique for forming the titanium carbonitride layer on at least a part of the molding surface is not particularly limited, but specific examples include the PVD method (physical vapor deposition method) and the CVD method (chemical vapor deposition method). can be mentioned.

<effect>
As described above, in the fourth crimping die, the titanium carbonitride layer is formed on at least a part of the molding surface, so that the coefficient of friction between the molding surface and the diameter-reduced portion can be reduced. Therefore, according to the fourth crimping die, the formation of the extra portion (knob portion) on the mating surface of the partial dies (partial surface of the crimping die) is more effectively suppressed, and the press type pipe joint and the piping element are further separated. An airtight or liquidtight connection can be ensured.

<<Fifth Embodiment>>
A press crimping die (hereinafter sometimes referred to as a "fifth crimping die") according to a fifth embodiment of the present invention will be described below with reference to the drawings.

As described above, in each of the partial molds constituting the first to fourth crimping dies, the contact area between the molding surface and the diameter-reduced portion is reduced by the concave portion provided between the adjacent pressing surfaces. and dispersing and/or alleviating the strain associated with the reduction in diameter of the diameter-reduced portion suppresses the formation of a surplus portion (knob portion) and ensures airtightness or liquidtightness between the press-type pipe joint and the piping element. can be connected to

In addition, similarly to the press crimping die (conventional crimping die) according to the above-described conventional technology, a diameter-reduced portion having a substantially hexagonal cross section (hexagonal cross-section diameter-reduced portion) is formed on both sides or one side of the annular bulging portion. Therefore, the occurrence of relative movement (eg, indexing and/or disengagement, etc.) between the press fitting and the piping element is also reduced.

However, depending on the application of the press-type pipe joint, the press-type pipe joint and the piping element may be fixed and connected more firmly to prevent relative movement (for example, indexing and/or disengagement) between the two. may be required to be reduced to

<Constitution>
Therefore, the fifth crimping mold is any one of the above-described first crimping mold to the fourth crimping mold, and a projection protruding inward in the radial direction of the press-type pipe joint is formed on at least one pressing surface. It is a press caulking die characterized by being.

FIG. 12 is a schematic diagram showing an example of the configuration of one of a pair of partial molds forming the fifth caulking mold. Specifically, FIG. 12(a) is a schematic front view of the partial mold 110 included in the fifth crimping mold 105, and FIG. 3A and 3B are schematic cross-sectional views, and (c) is a schematic plan view when the partial mold 110 illustrated in (a) and (b) is observed from the dividing surface side. However, in (c), the reference numerals for the concave portions are omitted, and the reference numerals for the pressing surfaces 113a, 113b, and 113c and the projections 116 formed on these pressing surfaces indicate the axial direction of the press type pipe joint (not shown). are attached to only one of the positions facing each other with the annular groove portion 112 interposed therebetween.

As illustrated in (a) of FIG. 12 , the partial mold 110 constituting the fifth crimping mold 105 is also subjected to three presses in the same manner as the partial mold 110 constituting the first crimping mold 101a. Surfaces 113a, 113b and 113c are formed on the molding surface 111. A concave portion 114a is formed between the adjacent pressing surfaces 113a and 113a, and a concave portion 114b is formed between the adjacent pressing surfaces 113b and 113c. are provided respectively. In addition, each of the three pressing surfaces 113a, 113b and 113c is formed with one projection 116 projecting inward in the radial direction of the press type pipe joint (not shown).

FIG. 12(b) is a schematic cross-sectional view of a plane including the axis of the press type pipe joint indicated by line FF of the partial mold 110 illustrated in (a). is a schematic cross-sectional view of a portion of the partial mold 110 where the pressing surface 113c is formed, as is apparent from FIG. Pressing surfaces 113c are formed on both sides in the axial direction (double arrow of broken line) of the annular groove portion 112 fitted to the annular swelling portion of the press-type pipe joint (not shown). In addition, each of these two pressing surfaces 113c is formed with one protrusion 116 protruding inward in the radial direction of the press-type pipe joint. Although not shown, the same applies to the portion of the partial mold 110 on which the pressing surface 113b is formed and the portion on which the pressing surface 113a is formed.

Further, as illustrated in (c) of FIG. 12 , in the partial molds 110 constituting the fifth crimping mold 105 , positions facing each other across the annular groove 122 in the axial direction of the press-type pipe joint (not shown) are formed with three pressing surfaces 113a, 113b and 113c, respectively. In addition, each of the pressing surfaces 113a, 113b, and 113c is formed with one projection 116 projecting inward in the radial direction of the press type pipe joint (not shown).

Although the drawing corresponding to FIG. 12 of the other partial mold 120 of the fifth crimping mold 105 is omitted, the partial mold 120 also has the same configuration as the partial mold 110 described above.

The configuration of the projections formed on the pressing surface (e.g., shape, size, height, number of projections formed on one pressing surface, etc.) is It is determined appropriately according to various factors such as the mechanical strength, hardness, friction coefficient between the press type pipe joint and the piping element, and the connection strength between the press type pipe joint and the piping element required for the use of the press type pipe joint. be able to. Also, the number of pressing surfaces on which the projections are formed and the positions on which the projections are formed on the pressing surfaces can also be appropriately determined according to various factors, as described above. From the viewpoint of alleviating the distortion caused by the diameter reduction of the diameter-reduced portion even in the concave portion, it is desirable to form the projection at a position as far away from the concave portion as possible. Specifically, it is desirable to form a protrusion at or near the center of the pressing surface.

<effect>
As described above, in the fifth crimping die, at least one pressing surface is provided with a projection projecting inward in the radial direction of the press-type pipe joint. The protrusions formed on the pressing surface in this manner press the diameter-reduced portion more locally and deeply in the process of diameter-reducing the diameter-reduced portion. As a result, according to the fifth crimping die, the press-type pipe joint and the piping element are fixed and connected more firmly to prevent relative movement (for example, indexing and/or disengagement) between the two. can be reliably reduced.

Although several embodiments having specific configurations have been described, at times with reference to the accompanying drawings, for the purpose of illustrating the present invention, the scope of the present invention is not limited to these exemplary embodiments. It should not be construed as limiting, and it goes without saying that modifications can be made as appropriate within the scope of the claims and the matters described in the specification.

Reference Signs List 101a, 101b, 102, 103, 105... Press caulking dies 110, 120, 130... Partial dies 111, 121... Molding surfaces 113a, 113b, 113c, 123a, 123b, 123c... Pressing surfaces 114a, 114b, 124a, 124b ... Recessed portion 115 ... Inclined portion 116 ... Protrusion 210, 211, 212 ... Piping element 220 ... Press type pipe joint 221 ... Socket portion 222 ... Annular bulging portion 230 ... Sealing member (O-ring)

Claims (5)

an annular groove that is an annular depression having a shape corresponding to the annular bulge of the press-type pipe joint;
disposed around the axis of the press-type pipe joint so as to surround diameter-reduced portions, which are portions of the press-type pipe joint positioned on both sides or one side of the annular bulging portion in the axial direction of the press-type pipe joint. pressing surfaces, which are six flat surfaces facing the diameter-reduced portion;
has a molding surface on which is formed
configured to reduce the diameter of the diameter-reduced portion by pressing the diameter-reduced portion with the pressing surface,
A press caulking mold,
The press crimping die is divided into two or three partial dies around the axis of the press type pipe joint,
When the press crimping die is divided into two partial dies, each of the partial dies has three pressing surfaces,
When the press crimping die is divided into three partial dies, each of the partial dies has two pressing surfaces,
In each of the partial molds, at the corner portion between the adjacent pressing surfaces, both or one of virtual pressing surfaces, which are two planes obtained by respectively extending the adjacent pressing surfaces, is provided. is provided with a recess defining a space extending outward in the radial direction of the press-type pipe joint,
A press caulking die characterized by: A press caulking die according to claim 1,
At both ends in the axial direction of the press-type pipe joint at both ends in the circumferential direction of the molding surface of the partial mold, the distance from the axis of the press-type pipe joint increases toward the ends in the axial direction of the press-type pipe joint. An inclined portion is provided, which is an inclined portion such as
A press caulking die characterized by: The press caulking die according to claim 1 or claim 2,
At the inner end of the recess in the axial direction of the press-type pipe joint, the depth of the recess in the radial direction of the press-type pipe joint becomes shallower toward the inner side in the axial direction of the press-type pipe joint. A certain gradual change is provided,
A press caulking die characterized by: The press caulking die according to any one of claims 1 to 3,
A titanium carbonitride layer is formed on at least a portion of the molding surface,
A press caulking die characterized by: The press caulking die according to any one of claims 1 to 4,
At least one of the pressing surfaces is formed with a projection projecting inward in a radial direction of the press-type pipe joint,
A press caulking die characterized by:

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