JP2503701Y2 - Pipe expanding mandrel - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a pipe expanding mandrel for a heat exchanger, and more particularly to a pipe expanding mandrel used by press-fitting into a pipe when expanding the pipe.

[0002]

2. Description of the Related Art As is well known in the prior art, in this type of pipe expanding mandrel, the size of the pipe expanding billet provided at the tip end must be successively 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, as shown in FIGS. 7 and 8, a set pin having a pipe expanding billet 14 corresponding to the inner diameter of the pipe expanding the pipe at the tip portion.
15 and a sleeve that is slidably fitted on the rear side of the set pin 15 in a rotation-stopped state with respect to the set pin 15.
16 and an elastic body 17 housed in the sleeve 16 and for urging the sleeve 16 toward the rear end portion side of the set pin 15, and further, the rear end portion of the set pin 15 And the tip of the mandrel 18 are engaged with and disengageable from each other in order to connect the set pin 15 and the mandrel 18 to each other by rotation displacement of the set pin 15 and the mandrel 18 so as to connect them in a retaining state. 20 are provided respectively, and the sleeve
Both the rear end of the mandrel 16 and the tip of the mandrel 18 are engaged with each other by engaging protrusions 21 and 21 and an engaging groove 22 which can be engaged with each other so that both the sleeve 16 and the mandrel 18 are in a rotation stop state. ,twenty two
Are provided respectively.

[0005]

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

That is, in the above-described 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 direction toward the rear end 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 is reduced, a predetermined expansion work can be performed by exchanging the set pin equipped with the expansion billet according to the inner diameter of the pipe, but the inner diameter is less than a certain value. In that 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, is also reduced.

Therefore, there is a limit in reducing the shaft diameter of the set pin in order to secure the strength of the expanding mandrel.
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 mandrel for expanding the pipe is ensured while ensuring the strength of the mandrel for expanding the pipe. 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, since it can be made thin.

[0010]

That is, the present invention has an expanding billet 5 at one end and a hollow recess 6 at the other end.
And a set pin 2 that forms a
Is formed in a rod-shaped body 3a that can be inserted into and removed from the recessed portion 6 of the set pin 2, and an end 4a is formed in the rod-shaped body 3a so as to abut the opening peripheral edge portion 2b of the set pin 2 on the side of the recessed portion 6. An elastic body in which a sleeve 4 is movably fitted, and is fitted on the other side of the rod-shaped body portion 3a so as to urge the sleeve 4 toward the set pin 2 side. And a retaining part that prevents the bullet from falling off
3c and a mandrel shaft 3 having a rod-shaped head 3b provided with the rod-shaped head 3b, and the 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. The projections 8, 8 and the drilling groove 9, which can be engaged and disengaged with each other so as to connect them in a retaining state by a later rotational displacement.
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 rotated and moved by the sleeve 4. Are provided with guide holes 10, 10 bored along the axial direction of the rod-shaped body 3a and projections 11, 11 that fit into the guide holes 10, 10 in order to regulate the guide hole 10a within a predetermined range. In addition, the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side and the opening peripheral edge portion 2b
The end portions 4a of the sleeve 4 that abut against 2b are provided with engaging and disengageable convex portions 4b and 4b and concave portions 12 and 12, respectively, for preventing the rotation after the abutment. It is in.

[0011]

In the pipe expanding mandrel having the above-mentioned structure, the elastic body for urging the sleeve 4 movably fitted on the rod-shaped body 3a of the mandrel shaft 3 toward the set pin 2 side is provided. When the inner diameter of the pipe to be expanded is less than a certain value because it is externally fitted to the rod-shaped body 3a and is urged to come into contact with the end 4a of the sleeve 4. Also in this case, since the elastic body is not housed in the sleeve 4 unlike the conventional case, even if the shaft diameter of the mandrel 1 for pipe expanding is made the same as the conventional diameter, the shaft of the rod-shaped body portion 3a of the mandrel shaft 3 is The diameter can be increased to give a predetermined strength.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

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

Reference numeral 2 denotes a set pin having a tube-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 which 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 into a rod-shaped body portion 3a which 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 rod-shaped body portion
On the other side of 3a, a spring spring (elastic body) 7 is fitted to push the sleeve 4 toward the set pin 2 side.
And a rod-shaped head portion 3b provided with a retaining portion 3c for preventing the spring spring 7 from coming off.

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 provided on each other, and the recess 6 of the set pin 2 is provided.
And the rod-shaped body portion 3a of the mandrel shaft 3 which can be inserted into and removed from the recess 6
The cylindrical projections 8 and 8 and the substantially L-shaped drilling grooves 9 and 9 which can be engaged with and disengaged from each other so as to connect the both in a retaining state by rotation displacement after the both are fitted. It is provided.

Further, the rod-like body 3a of the mandrel shaft 3 and the sleeve 4 movably fitted on the rod-like body 3a are mutually rotated so that the sleeve 4 rotates and the sleeve 4 moves. Groove-shaped guide holes 10 and 10 formed along the axial direction of the rod-shaped body 3a so as to regulate the movement amount within a predetermined range, and the guide hole 1
Approximately cylindrical projections 11 and 11 penetrating 0 and 10 are provided respectively, and the opening peripheral edge portion 2b of the set pin 2 on the concave portion 6 side and the sleeve contacting the opening peripheral edge portion 2b are provided. Four
Ends 4a are provided with engaging and disengaging protrusions 4b and 4b and recesses 12 and 12, respectively, for preventing rotation after abutting.

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 tube expanding mandrel according to the present embodiment has the above-mentioned 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 at the other end of the set pin 2. At this time, Rod-shaped body
The protrusions 8, 8 provided on 3a are fitted into the substantially L-shaped holes 9, 9 formed in the recess 6 side of the set pin 2,
Moreover, by rotating the set pin 2 in the predetermined direction along the drilled holes 9, 9, the set pin 2 and the mandrel shaft 3 can be engaged with each other in a retaining state.

The mandrel shaft 3 engaged in the retaining state as described above is provided with a sleeve 4 having a rotation and movement amount of the mandrel shaft 3 regulated within a predetermined range via an elastic body. The opening peripheral edge portion 2b on the side of the recess 6 of the set pin 2 and the opening peripheral edge portion 2b are biased toward the set pin 2 side.
Each of the end portions 4a of the sleeve 4 abutting against each other is provided with a freely disengageable convex portion 4b, 4b and a concave portion 12, 12 for preventing the rotation after the both contact. From the above, the set pin 2 and the mandrel shaft 3 which are once engaged in the retaining state are
It is possible to remove each other 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 unlike the conventional pipe expanding mandrel, but is set in the sleeve. Mandrel shaft 3 to be inserted into the recess 6 of 2
Since it is externally fitted to the rod-shaped body 3a, the shaft diameter of the rod-shaped body 3a of the mandrel shaft 3 can be increased even when the shaft diameter of the pipe expanding mandrel 1 is the same as the conventional one.

In the above embodiment, the expansion billet and the set pin are provided as separate members, but the specific mounting structure of the expansion billet and the set pin does not matter, for example, the expansion billet and the set pin. 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 which can be inserted into and removed from the recess is cylindrical. The protrusion is provided, but the point is that if a protrusion and a drilling groove are provided so that they can be engaged and disengaged in order to keep them from coming off due to rotational displacement after insertion of both, the protrusion is provided on the concave side of the set pin. The body or the rod-shaped body portion of the mandrel shaft may be provided with a perforation groove, and the specific shape, quantity, engagement / disengagement position, etc. are not limited at all.

Further, in the above-mentioned embodiment, the rod-shaped body of the mandrel shaft is provided with a cylindrical projection, and the sleeve fitted movably to the rod-shaped body has the rod-shaped body. Is provided with a guide hole formed along the axial direction of the portion, and the projection of the rod-shaped body is fitted into the guide hole formed in the sleeve to rotate the sleeve. And, the movement amount is regulated within a predetermined range, but it is needless to say that the configurations may be opposite to each other and the specific shape, quantity, etc. are not limited, and further, in the embodiment, the sleeve is provided. The elastic body for urging to the set pin side is a spring, but the point is, as long as it is externally fitted to the rod-shaped body of the mandrel shaft and urges the sleeve toward the set pin side. It may be a rod-shaped body such as rubber.

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 onto a female screw threaded on the rod-shaped head portion to be integrally formed. However, the present invention is by no means 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. May be

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

The specific shape, quantity, etc. 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 is used. It comprises a mandrel shaft, a sleeve fitted onto the rod-shaped body, and an elastic body fitted onto the rod-shaped body to urge the sleeve toward the set pin. Moreover, the set pin and the rod-shaped body are respectively provided with detachable projections and drilling grooves that connect the two by rotational displacement after they are inserted, and the rod-shaped body of the mandrel shaft and the The sleeves that are movably fitted to the rod-shaped body are fitted into the guide holes and the guide holes that are formed to regulate the rotation and movement of the sleeve within a predetermined range. A protrusion and a set pin and the set pin, respectively. Contacting the ground - the mutual Bed,
As long as engaging and disengaging convex portions and concave portions are respectively provided to prevent rotation after abutting on each other, the specific configurations thereof can be arbitrarily changed within the scope intended by the present invention.

[0030]

As described above, according to the present invention, a set pin having an expanding billet at one end and a hollow recess at the other end, and one side insertable into and removable from the recess of the set pin. A rod-shaped body, and a sleeve formed so that an end thereof abuts on the peripheral edge of the opening of the set pin on the recessed side is movably fitted on the rod-shaped body. Moreover, on the other side of the rod-shaped body, there is provided an elastic body fitted outside to urge the sleeve toward the set pin side, and a retaining portion for preventing the elastic body from coming off. A mandrel shaft having a rod-shaped head, and a mandrel shaft that can be inserted into and removed from the recess of the set pin, and the mandrel shaft that can be inserted into and removed from the recess. The mandrel shaft of the mandrel shaft is provided with a projecting body and a drilling groove that are detachable. The sleeve and the sleeve movably fitted on the rod-shaped body are arranged in the axial direction of the rod-shaped body so as to regulate the rotation and movement of the sleeve within a predetermined range. A guide hole bored along the guide hole and a projection that fits into the guide hole are provided, and the opening peripheral edge of the set pin on the concave side and the sleeve abutting against the opening peripheral edge are provided. Since the end portions are each provided with an engagement / disengagement convex portion and a concave portion for preventing rotation after abutting on each other, the shaft diameter having the sleeve storing the elastic body is the same. Even when compared with a conventional pipe expanding mandrel, 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 less than a certain value. Even in such a case, the shaft diameter of the pipe expanding mandrel can be appropriately reduced to match the inner diameter of the pipe to be expanded regardless of the shaft diameter of the rod-shaped body of the pipe expanding mandrel.

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 and the mandrel shaft are engaged by rotational displacement so that they can be connected in a retaining state, and the mandrel is A sleeve, which is in a rotation-stopped state with the mandrel shaft and is biased toward the set pin side, is externally fitted to the shaft, and the sleeve is engaged with the set pin when the set pin and the mandrel shaft are connected. Since the set pin is configured so as to surely prevent the set pin from rotating accidentally with respect to the mandrel shaft and coming out, it is very easy to replace the expansion billet without using any tool, and It also has a special effect that it 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.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2;

FIG. 4 is an enlarged sectional view taken along line BB of FIG. 2;

5 is an enlarged cross-sectional view taken along the 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 pipe 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)

(57) [Scope of utility model registration request] 1. 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 which is insertable into and removable from the recess 6 of the set pin 2 on one side. Department
A sleeve 4 which is formed on the rod-shaped body 3a and is formed so that the end 4a abuts on the opening peripheral edge 2b of the set pin 2 on the side of the recess 6 is movably fitted on the rod-shaped body 3a. In addition, on the other side of the rod-shaped body 3a, the elastic body 7 fitted externally to urge 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 which can be inserted into and removed from the concave portion 6 of the set pin 2 and the concave portion 6 are prevented from slipping off due to rotational displacement after the insertion of the both. In order to connect in a state, the projections 8, 8 and the 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 which fit into the guide holes 10 and 10, respectively, and further, the opening peripheral edge portion 2b on the concave portion 6 side of the set pin 2 and the slot which contacts the opening peripheral edge portion 2b. -The end portions 4a of the lug 4 are mutually engaged and disengaged with the convex portions 4b, 4b for preventing the rotation after they come into contact with each other. 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 a 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
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.