KR101353395B1 - Mandrel seal portion - Google Patents

Abstract

The present invention provides a mandrel seal portion of a hydraulic expansion device which makes it possible to improve the durability of the device and to improve the workability at the time of parts replacement.

The mandrel seal portion according to the present invention is an aqua tube (3) for encapsulating a high pressure liquid to enlarge the diameter, the backup ring (4, 4) mounted to the outer peripheral portion of the mandrel body 2 along the cross section before and after the aqua tube (3) And the fixed rings 5 and 5 mounted along the cross-sections of the backup rings 4 and 4 and the fixed rings 5 and 5, respectively. A mandrel seal 1 having annular expansion rings 6, 6, which is configured such that the inner diameter of the end of the fixing ring 5 on the side of the backup ring 4 is fixed to the outer surface of the mandrel body 2 and the fixing ring ( It is enlarged so that an accommodating part may be formed between the inner surfaces of 5).

Description

Mandrel seal portion

The present invention relates to a mandrel seal of a hydraulic expansion device.

At present, a roller expansion method, a hydraulic expansion method, a seal welding method, an explosion expansion method, and the like are used as a method of joining a pipe plate such as a heat exchanger or a condenser and a pipe plate. Among them, the hydraulic expansion method, which directly expands using a hydraulic pressure of thousands of atmospheres, is widely used because it can work in a clean environment with accurate and robust expansion using energy of hydraulic pressure. In the roller expansion method, peeling (flaking) may occur on the inner surface of the tube due to voltage, but in the hydraulic expansion method, the inner surface of the tube is provided with a uniform hydraulic pressure to expand, so that the contact pressure can be managed with high accuracy. It is possible to expand with high reliability.

As a mandrel sealing part of the hydraulic expansion device, as shown in FIG. 7, the aqua tube type which sealed the discharge part L2 of the high pressure liquid supply part of the mandrel main body 102 by the aqua tube 103, and prevented the leakage of a high pressure liquid (See Japanese Patent Application Laid-Open No. 58-49146).

The aqua tube type mandrel seal portion 101 is made of a mandrel body 102 into which a high pressure liquid is introduced, an aqua tube 103 for encapsulating a high pressure liquid, and a rubber supporting front and back of the aqua tube 103. It is comprised by the backup ring 104, the metal fixing ring 105 and the expansion ring 106 which formed the wedge shape and comprise an expansion mechanism. Moreover, the outer periphery of the mandrel main body 102, and behind the aqua tube 103, it has the collar 107 which accommodates the protrusion part of the pipe | tube material from a pipe plate, and positions the aqua tube 103 (expansion site | part).

The slit 106a is formed in the expansion ring 106 from the end face of the aqua tube 103 side toward the opposite side of the aqua tube 103 along the axial direction of the expansion ring 106.

With such a configuration, when the high pressure liquid is supplied, the aqua tube 103 expands (diameters enlarge) by the hydraulic pressure, and expansion pipe molding of the pipe member is performed. And after expansion pipe forming, the aqua tube 103 is elastically reduced in diameter and is comprised so that the mandrel main body 102 can be easily pulled out from a piping material.

By the way, since the contact surface of the back-up ring 104 and the fixed ring 105 is formed flat, the said conventional mandrel seal part 101 is pressurized by the expansion of the aqua tube 103 at the time of expansion pipe forming, and it compresses. A part of the deformed backup ring 104 was easily pushed out to the outer circumferential surface of the fixing ring 105. As a result, the backup ring 104 was exhausted.

Further, the backup ring 104 pushed out to the outer circumferential surface of the fixing ring 105 passes over the fixing ring 105 to the slit portion (between the fixing ring 105 and the expansion ring 106) of the expansion ring 106. There was a case of being cut off by entering.

Moreover, at the time of expansion pipe forming, a part of the backup ring 104 compressed and deformed may enter between the mandrel main body 102 and the fixed ring 105. As such, when a part of the backup ring 104 enters between the mandrel main body 102 and the fixing ring 105, the backing ring 104 is damaged, and at the same time, each part of the mandrel seal portion 101 is removed. At the time of exchange, there arises a problem that the detachment of the fixing ring 105 becomes difficult. Therefore, at the time of manufacture of the stationary ring 105, it is necessary to perform high precision processing which minimizes the clearance gap between the inner diameter of the stationary ring 105 and the outer diameter of the mandrel main body 102, and manufactures a hydraulic expansion device. It became obstacle of cost reduction.

An object of this invention is to provide the mandrel sealing part of the hydraulic expansion device which enabled the improvement of the durability of an apparatus, and the workability at the time of component replacement in order to solve the said problem.

In order to solve the said subject, invention of Claim 1 is a mandrel seal part which seals the said pipe material from the inner surface by sealing the high pressure liquid supplied from the main-body part through the expansion tool part in the state inserted into the pipe material, The expansion tool part A mandrel body connected to the high pressure liquid; A cylindrical elastic body mounted on an outer circumference of the mandrel body and encapsulating the high pressure liquid to enlarge the diameter; A backup ring mounted to an outer circumferential portion of the mandrel body along at least one end surface of the cylindrical elastic body; A fixing ring mounted to an outer circumferential portion of the mandrel body along an end surface opposite the cylindrical elastic body of the backup ring and having a wedge shape having an outer diameter reduced toward the end surface side opposite to the backup ring; It is attached to the outer peripheral part of the said mandrel main body along the cross section of the said wedge-shaped side of the said fixing ring, and has a tapered recessed part whose inner diameter extended toward the said fixing ring side so that it corresponded to the said wedge-shaped part, and the hydraulic pressure of the said high pressure liquid And an annular expansion ring configured to be pressurized by the tapered concave to expand in the radial direction. The inner diameter of the backing ring side end of the fixed ring is defined by the outer surface of the mandrel body. It is characterized in that it is enlarged so that a receiving space is formed between the inner surfaces of the fixing ring.

Since the mandrel seal portion of such a hydraulic expansion device has a receiving space formed in the fixed ring, the backing ring loaded with the pressing force in the expansion pipe molding enters the containing space, thereby suppressing it from being pushed out to the outer circumferential surface of the fixed ring. Therefore, it is possible to improve the life of a backup ring.

In addition, the receiving ring is formed in the fixing ring, whereby the fixing ring having a small thickness exhibits a function as an elastic body such as a dish spring. Therefore, by the pressing force of the cylindrical elastic body transmitted through the backup ring, it becomes elastically deformed in the direction of diameter enlargement actively, and it becomes possible to suppress that a backup ring pushes out to the outer peripheral surface of a fixed ring. In addition, the elastic force of the fixing ring makes it possible to quickly return the backup ring to its original state during decompression. Therefore, it is possible to prevent damage to the backup ring and to improve the life of the mandrel seal portion.

In addition, by forming a receiving space into which the backup ring can be placed in the fixed ring in advance, a part of the backup ring is prevented from entering the inside of the fixed ring and the mandrel body.

The term "high pressure" refers to the pressure necessary for expansion pipe molding, and generally means thousands of atmospheric pressures depending on the size and shape of the pipe. In addition, the liquid used as a "high pressure liquid" is not limited, Generally, water and oil are used.

In addition, the invention according to claim 2 is characterized in that, as the mandrel seal portion according to claim 1, a resin ring attached to an outer peripheral portion of the mandrel main body is disposed in the accommodation space.

According to such a mandrel seal portion, the resin ring is deformed by the pressing force of the backup ring during expansion pipe forming and reduced in the inner diameter direction of the resin ring, thereby preventing the backup ring from entering between the fixed ring and the mandrel body.

The invention according to claim 3 is the mandrel seal portion according to claim 1 or 2, wherein the section length of the wedge portion is 60% or more relative to the total length of the fixing ring.

According to such a mandrel seal portion, the deformation area of the backup ring can be made small, and the life of the mandrel seal portion can be improved.

According to the mandrel sealing part of the hydraulic expansion device which concerns on this invention, it became possible to improve the durability of an apparatus, and the workability at the time of component replacement.

Preferred embodiment of this invention is described in detail, referring an appropriate figure.

1 is a perspective view for demonstrating the whole structure of the hydraulic expansion device which concerns on this embodiment. 2 is a half sectional view showing a configuration of a mandrel seal portion according to the present embodiment. 3A and 3B are schematic views showing a mandrel seal portion, a pipe member, and a tube plate according to a preferred embodiment of the present invention, and Fig. 3A is a cross-sectional view showing a situation before expansion pipe forming in which a mandrel seal portion is inserted into a pipe member, and Fig. 3B is a mandrel seal. It is sectional drawing which shows the situation at the time of expansion pipe forming by a part.

As shown in FIG. 1, the mandrel sealing part 1 of the hydraulic expansion apparatus 10 which concerns on this embodiment is a hydraulic expansion apparatus which joins a tube board and the pipe | tube material inserted in the tube hole formed in the tube board through a high pressure liquid ( In 10), the high pressure liquid supplied from the main body part 11 is enclosed through the expansion pipe tool part 12 in the state inserted into the pipe material, and the pipe material is expanded from the inner surface. The hydraulic expansion device 10 includes a mandrel seal portion 1, a expansion tool portion 12 for injecting a high pressure liquid into the mandrel seal portion 1, and a main body portion 11 for supplying a high pressure liquid to the expansion tool portion 12. Has)

This mandrel seal part 1 is attached to the expansion tool part 12, and high pressure liquid is supplied from the main body part 11 through the high pressure tube 11a. Moreover, the expansion tool part 12 and the main body part 11 are connected by the hydraulic tube 11b for control, and the drain tube 11c for pressure reduction.

The mandrel seal part 1 is attached as an attachment of the hydraulic expansion device 10. The mandrel seal part 1 encloses a high pressure liquid in the state inserted into the pipe | tube material W1 which performs expansion pipe forming, and forms the high pressure chamber P, and the pipe | tube material W1 is made into the pressure of this high pressure chamber P. Expansion pipe molding is performed to join the pipe member W1 and the tube plate W2 (see FIG. 3B). In this embodiment, although the cross section is circular as a pipe material W1, the cross-sectional shape of the pipe material W1 is not limited.

As shown in FIG. 2, the mandrel seal part 1 is attached to the expansion tool part 12 (refer FIG. 1), and is attached to the mandrel main body 2 into which the high pressure liquid is introduce | transduced, and the outer peripheral part of this mandrel main body 2, , An aqua tube (cylindrical elastic body) 3 that forms a high-pressure chamber P (see FIG. 3B) by encapsulating a high pressure liquid between the pipe member W1 (see FIG. 3) and the mandrel body 2 to be processed. It is constructed in consideration of.

Moreover, the mandrel seal part 1 is back and forth in the axial direction of the mandrel main body 2 of the aqua tube 3, and the back-up ring 4 and this backup ring 4 in the axial direction of the mandrel main body 2 are carried out. It is comprised with the fixed ring 5 and the expansion ring 6 arrange | positioned so that it may support. And the slit part 6a is formed in the expansion ring 6 along the axial direction.

In addition, the outer periphery of the mandrel main body 2 and the back of the aqua tube 3, the collar (protrusion part accommodating member) 7 for adjusting an expansion pipe position is attached.

As shown in FIG. 2, the mandrel main body 2 is a member formed in the shape of a round bar, and communicates from the end surface (right end surface in this figure) to the aqua tube 3 to the expansion pipe part 12 (FIG. 1) side ( The flow path L1 of the high pressure liquid which flows is formed to the center part of the mandrel main body 2 along the axial direction, and the communication hole L2 which communicates from the center part of the mandrel main body 2 to the aqua tube 3 is provided. . In this embodiment, one communication hole L2 is provided. However, the number of communication holes L2 is not limited, and four communication holes L2 may be provided radially, for example.

Moreover, the head adapter 2a connected to the expansion tool part 12 (FIG. 1) is attached to the back of the mandrel main body 2 (right side in this figure). On the other hand, the nut 2b is screwed to the front (left side in this figure) of the mandrel main body 2.

The aqua tube 3 is a bag-shaped member made of any one of nylon, urethane rubber, soft vinyl chloride, nitrile rubber, and fluorine rubber, for example, and is provided on the outer circumferential surface of the mandrel body 2 as shown in FIG. It is. When the high pressure liquid is introduced into the flow path L1 of the mandrel main body 2 and discharged from the communication hole L2, the aqua tube 3 forms a high pressure chamber P by enclosing the high pressure liquid inside ( 3b).

As shown in FIG. 2, the aqua tube 3 which concerns on this embodiment forms adhesive surfaces 3a and 3a by folding | folding both ends of a plate-shaped elastic material, and this adhesive surface 3a and 3a is a mandrel main body. It is formed in the shape of a tube by adhering in an annular shape along the outer circumferential surface of (2). It is assumed that the aqua tube 3 is completely in contact with the mandrel main body 2 so that the high pressure liquid enclosed therein does not leak. In addition, in this embodiment, although the aqua tube 3 is formed using the plate-shaped elastic material, the material which comprises the aqua tube 3 is not limited, For example, the both ends of a cylindrical elastic material may be used. By adhering, you may form an annular ring and arrange | position this to the outer periphery of the mandrel main body 2. In addition, if the material which comprises the aqua tube 3 is a material with strong elasticity and little abrasion, it is not limited to said thing.

As shown in FIG. 2, the backup ring 4 is provided along the cross section before and behind the aqua tube 3, forms a ring-shaped disk shape, and is comprised from elastic members, such as a urethane rubber. The backup ring 4 supports the force that the aqua tube 3 tries to return to its original shape after the expansion pipe molding in accordance with the deformation of the aqua tube 3 during the expansion pipe forming.

The fixed ring 5 is a metal member which forms a ring-shaped disk shape as shown in FIG.2 and FIG.3. The fixed ring 5 is formed with a wedge shaped portion 5a whose outer diameter is reduced toward the end face in contact with the expansion ring 6. The wedge-shaped portion 5a is suitable for the tapered portion 6b of the expansion ring 6 to be described later, and the fixed ring 5 is in a state where the tapered portion 6b and the wedge-shaped portion 5a are in close contact with each other. And extension ring 6 are engaged.

In this embodiment, the length of the front-back direction of the fixing ring 5 was formed in 2.6 mm, and the length of the front-back direction of the wedge-shaped part 5a was 2.1 mm, and the flat part was formed as 0.5 mm. In addition, although the shape dimension of the fixing ring 5 is not limited to the above-mentioned thing, The length of the front-back direction of the wedge-shaped part 5a is made with respect to the total length of the front-back direction of the fixing ring 5 preferably. It is 60% or more, More preferably, it is 80% or more.

In addition, in the fixed ring 5, as shown in FIG. 3A, an accommodating part (accommodating space) 5b into which an end portion of the backup ring 4 can enter at the end of the backup ring 4 is expanded. Formed. The accommodating part 5b is formed by enlarging the inner diameter of the fixing ring 5, and the internal resin ring 8 is arrange | positioned inside this accommodating part 5b.

The accommodating part 5b is formed by forming a taper in the inner surface of the edge part by the side of the backup ring 4 of the fixing ring 5, and expanding its diameter. And the inner resin ring 8 is attached to the outer periphery of the mandrel main body 2 in the corner part of the expansion ring 6 side of the accommodating part 5b.

The internal resin ring 8 is a resin-made elastic body that forms a ring-shaped disk. Although the material which comprises the internal resin ring 8 is not limited, In this embodiment, it is comprised by high strength engineering plastics. Examples of the high strength engineering plastics include polyimide, polycarbonate, polyacetal, polybutylene terephthalate, modified polyphenylene ether, and the like.

As shown in FIG. 2, the expansion ring 6 has a cylindrical shape.

As shown in FIG. 2 and FIG. 3A, the expansion ring 6 has a tapered portion 6b having an inner diameter that is enlarged toward the end face of the fixed ring 5 that is in contact with the fixed ring 5. . Further, the wedge-shaped portion 5a of the fixed ring 5 presses the tapered portion 6b to the expansion ring 6 so that the expansion ring 6 can expand in the radial direction by the hydraulic pressure of the high pressure liquid. The slit part 6a is formed.

In this embodiment, by setting the inclination angle which the wedge-shaped part 5a of the stationary ring 5 and the taper-shaped part 6b of the expansion ring 6 form suitably, the pressing force of the extension ring 6 in the diameter-expansion direction is set. And the stroke can be adjusted. For this reason, an optimum expansion pipe forming condition can be obtained by setting this inclination angle according to various conditions, such as the size of the pipe | tube material W1 which is a to-be-processed object, and the clearance gap (diameter expansion stroke) with the pipe plate W2.

The color 7 makes the aqua tube 3 at a predetermined position (expansion site) with respect to the tube plate W2 by making the length of the protrusion part from the tube plate W2 of the tube material W1 at the time of expansion pipe forming constant. It is a member which arrange | positions and makes it possible to perform expansion pipe forming with high quality.

That is, the mandrel seal is inserted into the space 7a of the predetermined length formed between the collar 7 and the expansion ring 6 in a state in which the tip portion (protrusion portion) protruding from the tube plate W2 of the tube member W1 is inserted. The length of the protruding portion of the pipe member W1 is pushed in by pushing the part 1.

The configuration of the color 7 is not limited as long as the length of the protruding portion of the pipe can be made constant.

Next, operation | movement of the mandrel sealing part 1 which concerns on this embodiment is demonstrated, referring FIG. 3A and FIG. 3B.

The mandrel seal part 1 is supplied with the high pressure liquid to the mandrel main body 2 in the state inserted into the pipe | tube material W1, such as a heat exchanger to expand (FIG. 3A), and expansion operation is started.

When a high pressure liquid is injected into the aqua tube 3 (high pressure chamber P) from the mandrel body 2 (flow path L1, communication hole L2), the aqua tube 3 expands (expands) in the radial direction. As a result, the pressing force acts on the pipe member W1.

By the hydraulic energy of the high pressure chamber P gradually increased in this manner, the pipe member W1 is expanded from the inside, and the outer surface of the pipe member W1 comes into contact with the inner surface of the hole of the tube plate W2. Then, when the pressure in the high pressure chamber P is further increased, the pipe member W1 is pressed by the tube plate W2 so that the hole of the tube plate W2 is elastically deformed. At this time, the pipe member W1 is deformed to the firing region, and after releasing the pressure in the high pressure chamber P, a contact residual stress is generated between the pipe member W1 and the tube plate W2, thereby firmly fixing.

On the other hand, when a high pressure liquid is injected into the aqua tube 3 (high pressure chamber P) from the mandrel main body 2 (the flow path L1 and the communication hole L2), the aqua tube 3 expands in the radial direction. As a result, the aqua tube 3 expands in the front-rear direction and the pressing force acts on the backup ring 4 before and after. When the pressing force acts on the backup ring 4, as shown in FIG. 3B, the backup ring 4 partially enters the receiving portion 5b of the fixing ring 5 so that the backup ring 4 is not easily expanded in the radial direction and is backed up. The ring 4 is prevented from being pushed out to the outer circumferential surface of the stationary ring 5.

Moreover, the backup ring 4 which entered into the accommodating part 5b gives a press force to the internal resin ring 8. The inner resin ring 8 is compressed and deformed by the pressing force acting through the backup ring 4, so that the outer surface is enlarged in diameter and the inner surface is reduced in diameter. In this way, the inner resin ring 8 is reduced in the inner diameter direction, so that the gap between the mandrel main body 2 and the fixed ring 5 is sealed so that the backup ring 4 is formed of the mandrel main body 2 and the fixed ring 5. To prevent entry.

Moreover, when the pressing force of the front-back direction acts on the fixed ring 5 via the backup ring 4, the fixed ring 5 elastically deforms to the expansion ring 6 direction, and the backup ring 4 is fixed ring 5 It is suppressed to be pushed out to the outer circumferential surface of).

In addition, when the pressing force acts on the fixing ring 5, the wedge-shaped portion 5a enters the tapered portion 6b, and the expansion ring 6 is enlarged in diameter. As a result, the pipe member W1 is expanded.

After the end of expansion pipe forming, when the high pressure chamber P is depressurized, the aqua tube 3 is contracted by the restoring force. When the aqua tube 3 contracts, the backup ring 4 returns to its original state early by the elastic force of the fixing ring 5 together with its restoring force.

Since the aqua tube 3 returns to an original state by depressurizing the high pressure chamber P, the mandrel seal part 1 can be easily taken out from the pipe | tube material W1.

As described above, according to the mandrel seal portion 1 of the hydraulic expansion device 10 of the present embodiment, the backup ring 4 is prevented from entering the outer peripheral surface and the inner peripheral surface of the fixing ring 5 during expansion pipe forming. (4) is not easily consumed, and the life of the mandrel seal 1 can be extended.

Further, the ratio of the wedge-shaped portion 5a of the fixed ring 5 to the total length of the fixed ring 5 is larger than that of the conventional fixed ring, and the parallel portion is formed small, so that the deformation area of the backup ring 4 (backup ring 4 Since it is possible to reduce the amount of) pushed out, it becomes possible to suppress the consumption of the backup ring 4.

In addition, the inner resin ring 8 is disposed in the receiving portion 5b, whereby the backup ring 4 is prevented from being pinched between the stationary ring 5 and the mandrel body 2. As a result, damage to the backup ring 4 is prevented, and the fixing ring 5 or the like is not prevented from being removed, thereby making it possible to improve the workability at the time of replacing the parts of the mandrel seal part 1. .

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to said embodiment and Example, It is possible to change suitably and to implement.

For example, in the said embodiment, although it set as the structure which arrange | positions an internal resin ring to a accommodating part, what is necessary is just to arrange | position an internal resin ring as needed, and it can be abbreviate | omitted.

In addition, in the said embodiment, although the structure which arranges a backup ring, a fixed ring, and an expansion ring before and behind an aqua tube, the same effect can be acquired even if an aqua tube is an O-ring, either one of the front or the back of an aqua tube. It is good also as a structure arrange | positioned only. In addition, in the said embodiment, you may make it the structure which suppresses consumption of an aqua tube by arrange | positioning an aqua cover in the outer periphery of an aqua tube.

In addition, the expansion pipe length (thickness of a pipe plate) of a pipe material is not limited, What is necessary is just to set suitably.

(Example)

Next, the results of empirical experiments conducted for the verification of the effect by the mandrel seal according to the present invention.

(1) Effect of receiving part (accommodating space) of fixing ring

First, the expansion pipe forming was repeatedly performed using the mandrel seals provided with the fixing rings having different shape receiving portions, and the life effects of the fixing rings formed with the accommodating portions were verified by comparing the lifespans of the respective mandrel sealing portions. 4A, 4B, and 4C are schematic diagrams showing the shape of the fixing ring of each case used in this demonstration experiment, in which Fig. 4A shows Case 1, Fig. 4B shows Case 2, and Fig. 4C shows Comparative Examples. 5 is a graph which shows the result of this demonstration experiment.

In this demonstration experiment, as shown in Fig. 4A, a trapezoidal accommodating portion 51b having a cross-sectional trapezoidal shape in which the taper angle θ1 is enlarged to 45 ° toward the cross section is formed at the end of the backup ring 4 side. As shown in FIG. 4B, the mandrel seal portion A1 (case 1) using the fixing ring 51 and the trapezoidal accommodating portion 52b in which the angle θ2 of the taper is enlarged to 65 ° toward the cross section. The life of each mandrel seal part A1, A2 was measured about the mandrel seal part A2 (case 2) using the fixed ring 52 formed in the edge part of the backup ring 4 side. In addition, as a comparative example, as shown in FIG. 4C, the mandrel seal part A3 using the conventional fixing ring 53 in which the accommodating part was not formed was also verified.

In this demonstration, the fixing ring has a maximum outer diameter of 20.9 mm, a minimum inner diameter of 16.1 mm, an overall thickness (total length) (B) of about 2.6 mm, and a tapered portion (length) (B2) of about 1.9 mm. Unification was carried out, and the expansion pressure was 214 MPa and the expansion time was 2 seconds.

In the case 1, as the fixing ring 51, the depth b (length in the front and rear direction) of the receiving portion is 0.6 mm, the inner diameter is about 18.0 mm to 19.2 mm, and the member thickness h of the cross section of the backup ring side is about 0.9 mm. Was used. In the case 2, as the fixing ring 52, the depth b (length in the front and rear direction) of the receiving portion is 0.6 mm, the inner diameter is about 18.0 mm to 20.5 mm, and the member thickness h of the cross section of the backup ring side is about 0.2. mm was used.

5 shows the verification results.

As shown in FIG. 5, the case 1 shows that the life of the mandrel seal portion A1 can be extended about 1000 times, and the mandrel seal portion A2 of the case 2 can perform about 300 times. Yes has been demonstrated. On the other hand, the conventional mandrel seal part A3 (comparative example) which does not have a accommodating part was about 200 times.

Therefore, it was demonstrated that the life of a mandrel seal part improves by providing an accommodating part in a fixing ring.

(2) Effect by length of wedge

Next, the result of the empirical experiment which carried out about prolonging the lifetime of a mandrel seal part is shown by increasing the ratio of the length with respect to the fixed ring total length of a wedge-shaped part.

Table 1 shows the shape dimensions and verification results of the fixing ring used in this demonstration.

In this demonstration experiment, the length B1 in the front-rear direction of the parallel part (part with constant outer diameter) is shortened compared with the comparative example 1 formed by the conventional general shape, and the ratio with respect to the total length of the wedge-shaped part (wedge shape) The lifespan of the mandrel seal part in the case where case 3 and case 4 which enlarged the part length B2 / total length B) were used was compared (refer FIG. 4C).

In the case 3, as shown in Table 1, the fixed ring whose ratio with respect to the total length of the fixed ring of a wedge-shaped part was 81% was used. In the case 4, the ratio of the wedge-shaped portion to the total length of the fixing ring was 81%, and a fixing ring in which an accommodating portion was formed at the backup ring side end portion was used. In addition, as a comparative example, in Comparative Example 2, a fixing ring having a ratio of the wedge-shaped fixing ring to 59%, and Comparative Example 3 to a wedge-shaped fixing ring of 35% was used.

In this demonstration experiment, the expansion pressure was 214 MPa, and the expansion time was 2 seconds.

Fixed ring shape Extension Parallel Wedge Wedge Shape / Overall Length Case 3 0.5 2.1 81% 291 Case 4 0.5 2.1 81% 1021 Comparative Example 2 1.5 2.1 59% 71 Comparative Example 3 4.0 2.1 35% 11

As shown in Table 1, the number of expansions of the case 3 and the case 4 whose wedge-shaped part is 81% becomes 291 times and 1021 times, respectively, and it is drastically compared with 71 times of the comparative example 2 which comprised the shape of the conventional general fixed ring. It has been demonstrated that the improvement to.

On the other hand, as in Comparative Example 3, it was demonstrated that when the thickness (total length) of the fixing ring was increased to reduce the ratio of the wedge-shaped portion, the number of expansion was 11 times and the consumption was increased.

Therefore, if the length of the wedge-shaped portion of the fixing ring is 60% or more, more preferably 80% or more with respect to the total length of the fixing ring, the life of the mandrel seal portion can be extended.

(3) effect by resin ring

Next, the result of having verified the effect of the life improvement of a mandrel seal part by which a fixed ring is equipped with a resin ring is shown. 6A and 6B are sectional views showing a part of the mandrel seal portion used in the present demonstration experiment, and FIG. 6A shows a case where a conventional fixing ring is used (case 5), and FIG. 6B shows a case where a resin ring is installed (case 6). Indicates.

In this demonstration experiment, as shown in Figs. 6A and 6B, the resin rings 8 are arranged with respect to the stationary rings 54 and 55 provided on the mandrel seal portions B1 and B2, and those that do not arrange the resin rings 8 are used. Each expansion pipe molding was repeated, and the number of times the expansion pipe molding was performed until breakage occurred in the mandrel seal parts B1 and B2, respectively.

In this demonstration experiment, the expansion pressure was 214 MPa, and the expansion time was 2 seconds.

As the case 5, as shown in FIG. 6A, the case in which the resin ring is not arrange | positioned and the backup ring 4 side was formed in the fixed ring 54 formed flat (perpendicular to the axial direction of the mandrel main body 2), As shown in FIG. 6B, as shown in FIG. 6B, the outer ring shape is the same as the fixing ring 54 of the case 5, and the fixing ring 55 in which the resin ring 8 was provided in the inner surface side of the edge part by the side of the backup ring 4 is used. It was.

As the fixing rings 54 and 55, a maximum outer diameter of 20.9 mm, a minimum inner diameter of 16.1 mm, a total thickness (total length) of about 2.6 mm, and a tapered portion (length) of about 1.9 mm are used. It was.

Table 2 shows the experimental results.

Resin ring Extension Case 5 none 21 Case 6 has exist 71

As shown in Table 2, the life of the mandrel seal part of the case 6 in which the resin ring was arrange | positioned was 71 times, while the life of the mandrel seal part of the case 5 in which the resin ring was not arrange | positioned was 71 times. Therefore, it has been demonstrated that the life of a mandrel seal part can be improved significantly by arrange | positioning a resin ring in the inner surface part of the backup ring side of a fixing ring.

1 is a perspective view for explaining the overall configuration of a hydraulic expansion device according to a preferred embodiment of the present invention.

It is a half sectional view which shows the structure of the mandrel sealing part which concerns on preferable embodiment of this invention.

3A and 3B are schematic views showing a mandrel seal portion, a pipe member, and a tube sheet according to a preferred embodiment of the present invention. It is sectional drawing which shows the situation at the time of expansion pipe forming by a part.

4A, 4B and 4C are schematic diagrams showing the shape of the fixing ring of each case used in the demonstration experiment conducted to demonstrate the effect of the mandrel seal portion according to the present invention, and FIG. 4A is a case 1 and FIG. 4B is a case. 2, FIG. 4C is a sectional view of a comparative example.

FIG. 5 is a graph showing the results of an empirical experiment using the fixing ring shown in FIG. 4, showing the life of the mandrel seal portion on the vertical axis and the taper inclination angle of the region portion of the fixing ring on the horizontal axis.

6A and 6B are sectional views showing a part of a mandrel seal portion used in an empirical experiment on the effect of improving the life of the mandrel seal portion by arranging a resin ring in the fixing ring, and FIG. 6B shows a case where a resin ring is installed.

7 is a half sectional view showing a configuration of a conventional mandrel seal portion.

<Description of Symbols>

1 mandrel seal

2 mandrel body

3 aqua tube (cylindrical elastic body)

4 backup ring

5 fixed ring

5a wedge

5b accommodation part (accommodation space)

6 extension ring

6b tapered profile

8 inner resin ring (resin ring)

10 hydraulic expansion device

11 main body

12 expansion tool parts

P high pressure room

W1 material

W2 tube sheet

Claims (3)

A mandrel seal portion for sealing a high pressure liquid supplied from a main body portion through an expansion pipe tool portion and expanding the tube material from an inner surface while being inserted into the tube material. A mandrel body connected to the expansion tool and into which the high pressure liquid is introduced; A cylindrical elastic body mounted on an outer circumference of the mandrel body and encapsulating the high pressure liquid to enlarge the diameter; A backup ring mounted to an outer circumferential portion of the mandrel body along at least one end surface of the cylindrical elastic body; A fixing ring mounted to an outer circumferential portion of the mandrel body along an end surface opposite the cylindrical elastic body of the backup ring and having a wedge shape having an outer diameter reduced toward the end surface side opposite to the backup ring; It is attached to the outer peripheral part of the said mandrel main body along the cross section of the said wedge-shaped side of the said fixed ring, and has a taper-shaped part whose inner diameter extended toward the said fixed ring side corresponding to the said wedge-shaped part, And an annular expansion ring configured to be pressurized by the tapered portion to expand in a radial direction. The inner diameter of the backup ring side end part of the said fixing ring is enlarged so that the accommodation space may be formed between the outer surface of the said mandrel main body and the inner surface of the said fixing ring. The method of claim 1, And a resin ring attached to an outer circumferential portion of the mandrel body in the accommodation space. The method according to claim 1 or 2, The section length of the wedge-shaped portion is mandrel seal portion, characterized in that more than 60% of the total length of the fixing ring.

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