JPH0588728U - Expansion mandrel - Google Patents

Abstract

(57) [Summary] [Object] The present invention is capable of reducing the shaft diameter of the pipe expanding mandrel while ensuring the strength of the pipe expanding mandrel to be press-fitted even if the inner diameter of the pipe expanding becomes small. Accordingly, the present invention provides a mandrel for pipe expansion, which can be appropriately used for appropriate pipe expansion regardless of the inner diameter of the pipe to be expanded, and which has excellent workability. A resilient body for urging a sleeve movably fitted to a mandrel shaft of a pipe expanding mandrel toward the mandrel shaft side is externally fitted to the mandrel shaft on the end side of the sleeve. It is characterized by

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a pipe expanding mandrel of a heat exchanger, and more specifically to a pipe expanding mandrel used by press-fitting into a pipe when performing pipe expanding work.

[0002]

[Prior Art]

 As is well known in the art, in this type of pipe expanding mandrel, the size of the pipe expanding billet provided at the tip end must be sequentially changed corresponding to the inner diameter of the pipe to be expanded.

Therefore, there is a pipe expanding mandrel disclosed in Japanese Utility Model Publication No. 2-4728 for facilitating the attachment / detachment work.

That is, in the conventional pipe expanding mandrel described above, as shown in FIGS. 7 and 8, a set pin 15 having a pipe expanding billet 14 corresponding to the inner diameter of the pipe expanding at the front end, and the set pin 15. A sleeve 16 is slidably fitted to the rear side of the pin 15 in a rotation stop state with respect to the set pin 15, and is housed in the sleeve 16, and the sleeve 16 is attached to the rear end portion of the set pin 15. It is provided with an elastic body 17 for urging in the lateral direction, and if both the rear end part of the set pin 15 and the tip part of the mandrel 18 are provided with both the set pin 15 and the mandrel 18, An engaging projection 19 and an engaging hole 20 which are engageable with and disengageable from each other are provided so as to connect the two in a retaining state by rotational displacement, and the rear end of the sleeve 16 and the front end of the mandrel 18 are provided. And the sleeve 16 and mandrel 18 on both For mutually engageable engaging in order to both as a stop state protrusions 21, 21 and the engagement groove 22, 22 is one provided respectively.

[0005]

[Problems to be solved by the device]

 However, the conventional pipe expanding mandrel has the following problems.

That is, in the conventional pipe expanding mandrel, a sleeve is slidably fitted to the rear side of the set pin in a rotation stop state with respect to the set pin in the rear end side direction of the set pin. An elastic member for urging is housed in the sleeve and externally fitted to the set pin.

Therefore, when the inner diameter of the pipe to be expanded becomes small, the predetermined expansion work can be performed by exchanging the set pin equipped with the expansion billet according to the inner diameter of the pipe. In this case, the shaft diameter of the set pin must be reduced so that the outer diameter of the sleeve fitted over the set pin, that is, the shaft diameter of the so-called pipe expanding mandrel, must also be reduced.

[0008] Therefore, there is a limit in securing the strength of the pipe expanding mandrel to make the shaft diameter of the set pin thin, and there is a problem that the pipe to be expanded is limited by the inner diameter of the pipe. .

Therefore, the present invention solves the above-mentioned problem, and even if the inner diameter of the pipe for expanding the pipe becomes small, the shaft diameter of the pipe expanding mandrel is ensured while securing the strength of the mandrel for expanding the pipe. Therefore, it is an object of the present invention to provide a pipe expanding mandrel with extremely high production efficiency that can perform appropriate pipe expansion regardless of the inner diameter of the pipe to be expanded.

[0010]

[Means for Solving the Problems]

 That is, the present invention has a set pin 2 having a tube expansion billet 5 on one end side and a hollow recess 6 on the other end side, and a rod-shaped barrel on one side that can be inserted into and removed from the recess 6 of the set pin 2. A sleeve 4 is formed on the rod-shaped body 3a so that the end 4a is in contact with the opening peripheral edge 2b of the set pin 2 on the concave portion 6 side. On the other side of the rod-shaped body portion 3a, the elastic body fitted to the sleeve 4 to urge the sleeve 4 toward the set pin 2 side and the escape of the elastic body are removed. A mandrel shaft 3 having a rod-shaped head 3b provided with a retaining portion 3c for blocking, and a rod-shaped body 3a of the mandrel shaft 3 which can be inserted into and removed from the recess 6 of the set pin 2 and the recess 6. Are the projections 8 and 8 which can be engaged / disengaged with each other so as to connect the both in a retaining state by the rotational displacement after the insertion of both Grooves 9 and 9 are respectively provided, and the rod-shaped body portion 3a of the mandrel shaft 3 and the sleeve 4 movably fitted to the rod-shaped body portion 3a are interlocked with each other by the sleeve 4 Guide holes 10 and 10 formed along the axial direction of the rod-shaped body 3a so as to regulate the rotation and movement amounts of the guide holes 10 and 10 into the guide holes 10 and 10, respectively. Are provided respectively, and furthermore, the opening peripheral edge 2b of the set pin 2 on the side of the recess 6 and the end 4a of the sleeve 4 contacting the opening peripheral edge 2b are not contacted with each other. The point is that the protrusions 4b and 4b and the recesses 12 and 12 that can be freely engaged and disengaged are provided to prevent rotation.

[0011]

[Action]

 In the pipe expanding mandrel having the above-mentioned structure, the elastic body for urging the sleeve 4 movably fitted to the rod-shaped body portion 3a of the mandrel shaft 3 toward the set pin 2 side is the rod-shaped body. In the case where the inner diameter of the pipe to be expanded is less than a certain value, it is fitted onto the body 3a and is urged so as to come into contact with the end 4a of the sleeve 4. However, since the elastic body is not stored in the sleeve 4 unlike the conventional case, even if the shaft diameter of the expanding mandrel 1 is made the same as the conventional one, the rod body 3a of the mandrel shaft 3 has a large shaft diameter. Then, a predetermined strength can be provided.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a pipe expanding mandrel.

Reference numeral 2 denotes a set pin having a pipe expanding billet 5 at one end and a hollow recess 6 at the other end.

The expanding billet 5 is detachably screwed to the set pin 2 via a male screw 5a that can be screwed into a female screw portion 2a provided at one end of the set pin 2.

Reference numeral 3 denotes a mandrel shaft, one side of which is formed in a rod-shaped body portion 3a that can be inserted into and removed from the recess 6 of the set pin 2, and the rod-shaped body portion 3a has an end 4a. The sleeve 4 formed so as to come into contact with the opening peripheral edge portion 2b on the concave portion 6 side is movably fitted on the outside, and the sleeve 4 is attached to the other side of the rod-shaped body portion 3a. A bar-shaped head 3b is provided, which is provided with a spring spring (elastic body) 7 that is externally fitted to urge it toward the set pin 2 side, and a retaining portion 3c that prevents the spring spring 7 from coming off. Become.

The rod-shaped body portion 3a and the rod-shaped head portion 3b are detachably screwed by the male screw 3d and the female screw 3e respectively provided on the rod-shaped body 3a. The rod-shaped body 3a of the mandrel shaft 3 which can be inserted into and removed from the recess 6 has a cylindrical protrusion 8 which can be engaged with and disengaged from each other so as to connect the both in a retaining state due to the rotational displacement after the insertion. 8 and substantially L-shaped drilling grooves 9 and 9 are provided, respectively.

Further, the rotation of the sleeve 4 and the movement of the sleeve 4 between the rod-shaped body portion 3a of the mandrel shaft 3 and the sleeve 4 movably fitted on the rod-shaped body portion 3a. Groove-shaped guide holes 10 and 10 formed along the axial direction of the rod-shaped body 3a in order to regulate the movement amount of the rod-shaped body 3a in a predetermined range, and a substantially cylindrical projection penetrating the guide holes 10 and 10. The body 11 and the body 11 are provided respectively, and the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side and the end portion 4a of the sleeve 4 abutting on the opening peripheral edge portion 2b are mutually disposed. Releasable protrusions 4b and 4b and recesses 12 and 12 are respectively provided to prevent rotation after contact.

Reference numeral 13 denotes a male screw for mandrel screwing, which is projected on the upper surface 3f of the rod-shaped head 3b.

The pipe expanding mandrel according to the present embodiment has the above-described structure. The usage and operation of the mandrel will be described below.

First, as shown in FIGS. 1 and 2, the rod-shaped body portion 3a of the mandrel shaft 3 is inserted into the hollow recess 6 formed on the other end side of the set pin 2. The protrusions 8 and 8 provided on the rod-shaped body 3a are fitted into the substantially L-shaped drill holes 9 and 9 formed on the recess 6 side of the set pin 2, and the drill holes 9 and 9 are formed. The set pin 2 and the mandrel shaft 3 can be engaged with each other in a pull-out preventing state by rotating the set pin 2 in a predetermined direction along the direction.

As described above, the mandrel shaft 3 engaged in the retaining state is provided with a sleeve 4 whose rotation and movement amount on the mandrel shaft 3 are regulated within a predetermined range via an elastic body. The opening peripheral portion 2b of the set pin 2 on the side of the concave portion 6 and the end portion 4a of the sleeve 4 abutting the opening peripheral portion 2b are urged toward the set pin 2 side, and are not in contact with each other. Since the projections 4b and 4b and the recesses 12 and 12 which can be freely engaged and disengaged to prevent the rotation after the contact, are provided, respectively, the set pin 2 and the mandrel shaft which are engaged in the retaining state once. 3 can be removed only when the sleeve 4 is moved and rotated in a direction against the biasing force of the elastic body.

Further, an elastic body for urging the sleeve 4 toward the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side is not stored in the sleeve like a conventional pipe expanding mandrel but is set in the set pin 2. Since the mandrel shaft 3 is inserted into the recess 6 of the mandrel shaft 3 and is fitted onto the rod-shaped body 3a of the mandrel shaft 3, the rod-shaped mandrel shaft 3 has a rod-like shape even if the pipe diameter of the mandrel 1 for pipe expansion is the same as the conventional one. The shaft diameter of the body portion 3a can be increased.

In the above embodiment, the expansion billet and the set pin are provided as separate members. However, the specific mounting structure of the expansion billet and the set pin is not a question, and for example, the expansion billet The set pin and the set pin may be integrally formed by the same member.

Further, in the above embodiment, a substantially L-shaped drilling groove is provided on the recess side of the set pin, and the rod-shaped body of the mandrel shaft that can be inserted into and removed from the recess has a cylindrical shape. The protrusion is provided, but the point is that if a detachable protrusion and a drilling groove are provided so that they can be prevented from coming off due to rotational displacement after both are inserted, they will protrude to the concave side of the set pin. The starting body may be provided with a perforation groove in the rod-shaped body of the mandrel shaft, and the specific shape, quantity, engagement / disengagement location, etc. are not limited.

Further, in the above-mentioned embodiment, the rod-shaped body of the mandrel shaft is provided with a cylindrical protrusion, and the sleeve fitted movably to the rod-shaped body has the rod-shaped body. A guide hole is provided along the axial direction of the body, and the protrusion of the rod-like body is fitted into the guide hole formed in the sleeve to allow the sleeve to be inserted. Although the rotation and movement amounts are regulated within a predetermined range, it is needless to say that the configurations may be opposite to each other, and the specific shape, quantity, etc. are not limited. The elastic body for urging the sleeve toward the set pin side is composed of a spring spring. The point is that the elastic body is externally fitted to the rod-shaped body of the mandrel shaft to urge the sleeve toward the set pin side. If so, a rod-shaped body such as rubber may be used.

The mandrel shaft is composed of a rod-shaped head portion and a rod-shaped body portion, and a male screw provided on the rod-shaped body portion is screwed to a female screw threaded on the rod-shaped head portion to be integrally formed. However, the present invention is not limited to this, and the mandrel shaft may be formed integrally from the same member, and the shaft diameter of the rod-shaped head is the same as that of the rod-shaped body. It may be the diameter.

Further, the rod-shaped head of the mandrel shaft is provided with either a male screw or a female screw for attaching the mandrel shaft to a predetermined mandrel. Needless to say, it is not limited to screwing through a screw as long as it can be detachably attached to the mandrel, and may be detachably configured by various attaching / detaching means.

The specific shape and quantity of the set pin, mandrel shaft, sleeve, etc. in the present invention are by no means limited, and the point is that a rod-shaped body that can be inserted into and removed from the set pin. A mandrel shaft, a sleeve fitted on the rod-shaped body, and a resilient body fitted on the rod-shaped body to urge the sleeve toward the set pin. In addition, the set pin and the rod-shaped body are respectively provided with detachable projections and drilling grooves that connect the set pin and the rod-shaped body by rotational displacement after they are inserted, and the rod-shaped body of the mandrel shaft. Of the sleeve and the sleeve movably fitted to the rod-shaped body, and a guide hole and a guide hole formed to regulate the rotation and movement of the sleeve within a predetermined range. And a protrusion that fits in the set pin and the set pin. If the sleeves that abut the contact pins are each provided with a disengageable convex portion and a concave portion that prevent rotation after they come into contact with each other, the specific configuration is all that of the present proposal. The design can be changed freely within the intended range.

[0030]

[Effect of the device]

 As described above, the present invention has a set pin having an expanding billet at one end and a hollow recess at the other end, and a rod-shaped body at one end that can be inserted into and removed from the recess of the set pin. A sleeve is formed on the rod-shaped body so that the end of the sleeve is formed so as to abut the opening peripheral edge of the recessed side of the set pin, and the sleeve is movably fitted on the sleeve. On the other side of the body part, a rod-shaped head provided with an elastic body fitted to urge the sleeve toward the set pin side and a retaining portion for preventing the elastic body from coming off. The mandrel shaft, which is composed of a mandrel shaft having a portion, and which can be inserted into and removed from the recess of the set pin, and the mandrel shaft which can be inserted into and removed from the recess, are connected to each other so as to prevent them from coming off due to the rotational displacement after the insertion. Each of the mandrel shaft has a rod-shaped body provided with a detachable protrusion and a drilling groove. And the sleeves movably fitted on the rod-shaped body are pierced along the axial direction of the rod-shaped body so as to regulate the rotation and movement of the sleeve within a predetermined range. The set guide hole and the projection body that fits into the guide hole are provided, and the opening peripheral edge portion of the recess side of the set pin and the end portion of the sleeve that abuts against the opening peripheral edge portion are provided. Since the projection and the recess which can be freely engaged and disengaged to prevent the rotation after they come into contact with each other are respectively provided, the conventional expansion pipe having the same shaft diameter and having the sleeve storing the elastic body Even in the case of comparison with a mandrel for use, the shaft diameter of the rod-shaped body of the mandrel can be made larger, and stronger shaft strength can be obtained.

Therefore, even if the mandrel for pipe expansion has the same shaft diameter, the shaft diameter of the rod-shaped body of the mandrel can be made larger than before, so that the inner diameter of the pipe to be expanded becomes a certain value or less. Even in such a case, regardless of the shaft diameter of the rod-shaped body of the pipe expanding mandrel, the shaft diameter of the pipe expanding mandrel can be appropriately reduced to the inner diameter of the pipe to be expanded.

Further, the pipe expanding mandrel according to the present invention is configured such that both the set pin having the pipe expanding billet at the tip end thereof and the mandrel shaft are engaged by rotational displacement so that they can be connected in a retaining state. A sleeve that is in a rotation-stopped state with the mandrel shaft and is biased toward the set pin side is externally fitted to the mandrel shaft, and the sleeve engages with the set pin when the set pin and the mandrel shaft are connected. Therefore, the set pin is configured so as to surely prevent the set pin from rotating carelessly with respect to the mandrel shaft and being pulled out.Therefore, the work of replacing the expansion billet is extremely easy without using any tool. It has a special effect that it is easy and can be done in a short time.

[Brief description of drawings]

FIG. 1 is a plan view showing a pipe expanding mandrel according to the present invention.

FIG. 2 is a partially cutaway exploded view of the pipe expanding mandrel of the present invention.

3 is an enlarged cross-sectional view taken along the line AA of FIG.

4 is an enlarged cross-sectional view taken along the line BB of FIG.

5 is an enlarged cross-sectional view taken along line CC of FIG.

6 is an enlarged cross-sectional view taken along line DD of FIG.

FIG. 7 is a partially cutaway plan view of a conventional tube expanding mandrel.

FIG. 8 is a partially cutaway plan view of a conventional tube expanding mandrel.

[Explanation of symbols]

 1 Pipe expanding mandrel 2 Set pin 3 Mandrel shaft 4 Sleeve 5 Pipe expanding billet 7 Spring spring (elastic body)

Claims (6)

[Scope of utility model registration request] 1. A set pin 2 having an expanding billet 5 on one end side and a hollow recess 6 on the other end side, and a rod-shaped barrel on one side which can be inserted into and removed from the recess 6 of the set pin 2. Department
A sleeve 4 is formed on the rod-shaped body portion 3a and is formed so that the end portion 4a is in contact with the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side. In addition, on the other side of the rod-shaped body 3a, the elastic body 7 fitted externally for urging the sleeve 4 toward the set pin 2 side and the escape of the elastic body 7 are removed. A rod-shaped head provided with a retaining portion 3c for blocking
The mandrel shaft 3 having 3b, and the rod-shaped body 3a of the mandrel shaft 3 and the mandrel shaft 3 which can be inserted into and removed from the recess 6 of the set pin 2 are prevented from slipping off by rotational displacement after they are inserted. In order to connect in a state, projections 8, 8 and drilling grooves 9, 9 which can be engaged and disengaged with each other are respectively provided, and the rod-shaped body 3a of the mandrel shaft 3 and the rod-shaped body 3a are movably externally attached. A guide hole 10, which is bored along the axial direction of the rod-shaped body 3a, is provided between the fitted sleeves 4 in order to regulate the rotation and movement of the sleeve 4 within a predetermined range. 10 and the projections 11 and 11 that fit into the guide holes 10 and 10, respectively, and further, the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side and the slot contacting the opening peripheral edge portion 2b. -The end portions 4a of the lug 4 are mutually engaged and disengaged with convex portions 4b, 4b and 4b for preventing rotation after abutting them. For expansion mandrel, characterized by comprising provided recesses 12, 12 Togaotto people. 2. A structure in which a rod-shaped body portion 3a of the mandrel shaft 3 and a rod-shaped head portion 3b provided on the other direction side of the rod-shaped body portion 3a are detachably provided by an attaching / detaching means. The pipe expanding mandrel according to claim 1, which is characterized in that. 3. The pipe expanding mandrel according to claim 1, wherein the attaching / detaching means is a male screw 3d and a female screw 3e provided on the rod-shaped body 3a and the rod-shaped head 3b of the mandrel shaft 3, respectively. 4. The pipe expanding mandrel according to claim 1, wherein the elastic body 7 is a spring spring. 5. The upper surface of the rod-shaped head 3b of the mandrel shaft 3
5. The mandrel shaft 3 is provided at 3f with one of a male screw and a female screw that can be attached to and detached from a predetermined mandrel. Expansion mandrel. 6. The pipe expanding mandrel according to claim 1, wherein the pipe expanding billet 5 is configured to be screwed to one end of the set pin 2.