CN213197348U - Buckling device for connecting hollow pipes - Google Patents

Abstract

The utility model relates to a withhold device for connecting hollow tube, include: the insert (1) comprises a connecting section and an inserting section, wherein the connecting section is used for connecting the first hollow pipe (3) and the inserting section (12) is used for inserting the second hollow pipe (4), a first boss (111) and a second boss (112) are arranged on the connecting section, and a clamping groove (113) is formed between the first boss and the second boss; a sleeve (2) having a radially inwardly projecting annular snap (21) which is press-fitted into a snap groove (113) of the insert when the sleeve is mounted on the insert section of the insert, and a second hollow tube is radially compressed between the insert section of the insert and the sleeve, the wall thickness of the end portions of the sleeve being smaller than the wall thickness of the intermediate portion. Through adjusting the insert diameter, can effectively connect the great air conditioner pipe of internal diameter, through axial space and atress difference between sleeve and the insert, lead to the body after the withholding difficult impaired under high temperature.

Description

Buckling device for connecting hollow pipes

Technical Field

The utility model relates to a withhold device for connecting hollow tube especially is arranged in connecting the air conditioner pipe of tubular metal resonator and high temperature resistance in the car.

Background

For connecting air conditioning pipes of automobiles, various buckling devices are known in the prior art for tightly connecting air conditioning pipes and metal pipes, see CN 106015780B, CN 109630771 a and the like. However, the air-conditioning pipe buckling device is only generally suitable for the air-conditioning pipe with the maximum inner diameter of about 19 mm. For larger inner diameter air conditioning ducts generally not applicable.

The air conditioning pipe may be made of different materials, such as PTFE (polytetrafluoroethylene, commonly known as teflon) steel wire woven pipe, multilayer composite rubber pipe, and the like. These air conditioning ducts may expand in high temperature environments, causing the air conditioning ducts to be damaged or even broken.

Therefore, there is a need for an improved crimping device for air conditioning ducts that addresses the above-mentioned problems. In particular, in some cases, such as in the arabian region, the challenge of larger inner diameter and higher working temperature of the air conditioning pipe of the passenger car is faced at the same time, and a buckling device which meets the two challenges needs to be developed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a withhold device for connecting the hollow tube, especially be arranged in connecting the air conditioner pipe of tubular metal resonator and high temperature resistance in the car, this withhold device can effectively connect the great air conditioner pipe of internal diameter to the body is difficult impaired under high temperature.

This purpose is through according to the utility model discloses a withhold device for connecting hollow tube solves, should withhold the device and include:

an insert comprising a connecting section for connecting the first hollow tube and an insertion section for inserting the second hollow tube, the insert being provided with a first and a second projection at the connecting section, the first and second projection forming a clamping groove therebetween;

a sleeve with an annular snap projecting radially inwards,

wherein, when the sleeve is mounted on the insertion section of the insert, the catch is pressed into the catch of the insert in a form-fitting manner, and the second hollow tube is radially compressed between the insertion section of the insert and the sleeve. The sleeve, the second hollow tube and the insert are pressed together tightly by pressing them radially inwards outside the sleeve by means of a crimping die.

The longitudinal cross section of the snap and the detent can have any shape, as long as a form fit is complied with, preferably a square, triangular, trapezoidal or drop-shaped structure.

The important improvement of the utility model is that the wall thickness of the end part of the sleeve is smaller than that of the middle part. Therefore, the buffer areas are formed at the two ends of the sleeve while the sufficient radial buckling pressure is ensured, and the damage caused by the transition expansion of the pipe is avoided.

It is also preferred that the insertion section of the insert has a tapered outer diameter, the smallest outer diameter of which is inserted into the second hollow tube. That is, the maximum outer diameter of the insertion section is at the end abutting the boss, specifically the second boss, and the minimum outer diameter is at the end facing away from the boss. Therefore, the second hollow pipe can be conveniently inserted into the fixed position from the end with the smaller outer diameter, and the phenomenon that the second hollow pipe cannot be inserted into the fixed position due to accumulation of inner layer materials to cause product leakage can be avoided.

The insertion section of the insert can in this case taper off linearly in terms of its outer diameter, or else in a curved or undulating manner. Preferably, the outer surface of the insertion section of the insert is shaped as a cone, the inner diameter remaining constant. Further preferably, the taper angle of the taper (i.e. the angle between the circumferential outer surface and the circumferential inner surface of the taper) is between 2 ° and 5 °. If the taper angle is too small, the insertion and extrusion are not enough; if the taper angle is too large, a gap is generated in the radial direction.

Preferably, the first boss is axially wider than the second boss, and the outer diameter of the first boss is greater than the outer diameter of the second boss. Thus, when the sleeve is inserted into the insert before crimping, the snap of the sleeve passes over the intermediate second boss and stops against the end face of the first boss near the end. In addition, before the mould withholds, there is the clearance between the radial inner peripheral surface of sleeve buckle and the draw-in groove bottom surface of inserts, withholds through the mould, further extrudees the buckle inwards, finally supports against the draw-in groove bottom surface for sleeve and inserts are fixed reliably.

Preferably, the sleeve has a radially outwardly, e.g. flared, expansion section from which a second hollow tube is inserted between the sleeve and the insert. More preferably, the wall thickness of the expanded section of the sleeve is uniform. Thereby, on the one hand, the installation of the second hollow tube is facilitated; on the other hand, during the crimping process, although the external crimping die applies force to the whole sleeve equally, the expanded flare reduces the force effect due to the reduced wall thickness, thereby leaving an extrusion space for the material of the second hollow tube and preventing the second hollow tube from being crushed or even broken. Furthermore, the diameter of the second hollow tube may expand during use after crimping is complete, and the flared flare provides cushioning for it, preventing breakage.

Preferably, the outer circumferential surface of the sleeve has a circumferential crimping recess. It is further preferred that the outer circumferential surface of the sleeve is provided with at least two crimping grooves at intervals around the outer circumferential surface, and the radially deepest of these crimping grooves is in the region corresponding to the insertion section of the insert. During the crimping of the outer die, the entire sleeve is subjected to compression together. On the premise of ensuring tight buckling, the shorter the distance between the two buckling grooves of the sleeve is, the better the distance is, so that the length of the insertion section of the insertion piece corresponding to the requirement is shorter, and the whole buckling device occupies smaller structural space. Particularly preferably, exactly two crimping grooves are provided around the outer circumference of the sleeve at a distance.

In the case of two crimping grooves, a middle section is defined between the two crimping grooves of the sleeve. Preferably, the wall thickness of the intermediate section of the sleeve is greater than the wall thickness of the expansion section and the two crimping grooves. In contrast, the thin wall of the expansion section is helpful for controlling the transition of the second hollow pipe, particularly the PTFE pipe, from the natural state to the buckling state, thereby playing a role of buffering; the wall thickness of the middle section is beneficial to tighter buckling and good sealing performance of connection; the buckling grooves close to the two ends of the sleeve are radially inwards recessed to reduce the wall thickness, so that the stress on the end parts of the second hollow pipe, particularly the PTFE pipe, is not too large, the diameter is kept large, the second hollow pipe is not easy to pull off, and the second hollow pipe is not damaged due to too large pressure.

Preferably, both the connecting section and the insertion section of the insert project axially beyond the sleeve. Therefore, the phenomenon that the inner hole passing rate of the second hollow pipe is influenced by the radial inward flowing of the material of the second hollow pipe during buckling and even the inner wall of the pipe is damaged due to overlarge extrusion amount can be avoided.

The first hollow pipe to be connected is a hard pipe, and the second hollow pipe is a hose.

Preferably, the second hollow tube is a plastic tube or a plastic composite tube comprising an inner tube of plastic and an outer layer of braid. The end face of the second hollow tube is in contact with the end face of the second projection of the insert, which adjoins the insert section. Typically, the second hollow tube is an automotive air conditioning tube.

Preferably, the plastic inner pipe of the second hollow pipe is a PTFE inner pipe, and the outer layer of the braided fabric is a steel wire braided layer. Wherein, the material of the PTFE inner pipe is relatively easy to deform and flow in the buckling process. The outer steel wire braided layer increases the strength of the pipe, and is beneficial to working in a high-pressure environment.

Preferably, the plastic inner tube of the second hollow tube has a helical shape. For example, the second hollow tube may be provided with a screw thread on its circumferential surface, which screw thread facilitates bending of the tube.

Preferably, the first hollow tube is a metal tube, and the insert and the first hollow tube are connected by welding or integrally formed.

Preferably, the insert and the sleeve are constructed of steel.

Preferably, the crimping device according to the invention is free of adhesive. Sufficient tightness can be achieved only by mechanical crimping.

It should be noted that, as used herein, reference to "radial" means a direction from the central axis of the pipe to the circumferential surface of the pipe, and "axial" or "longitudinal" means a direction along or parallel to the central axis of the pipe. "radial" and "axial" are perpendicular to each other in the plane of the drawing.

The utility model has the advantages that:

the shape design of the sleeve fully considers the problems of reliable fixation of the sleeve and the insert and buckling of the sleeve, the air-conditioning pipe and the insert, and is convenient for simultaneously completing fixation of the sleeve and the insert and connection of the sleeve, the air-conditioning pipe and the insert through one-time buckling. The provision of the insert insertion section enables matching of large-diameter air conditioning tubes. The gap and the stress between the inside of the sleeve and the insert are different, and particularly the design of the horn mouth at the tail part ensures that the buckling edge of the air-conditioning pipe cannot be damaged or even broken due to excessive expansion, so that the use function of the air-conditioning pipe is prevented from being influenced by a high-temperature environment. In addition, the whole buckling and pressing process is completed mechanically without any adhesive, so that the method is more convenient and environment-friendly.

Drawings

Preferred embodiments of the invention are explained in detail below with the aid of the figures. Showing:

figure 1 shows an assembled crimping device according to the invention in a side view;

fig. 2 shows a crimping device according to the invention in an exploded view;

fig. 3 shows a crimping device according to the invention in a perspective view and in a partially sectioned view, after crimping has been completed.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following description is given for clarity and completeness with reference to the embodiments, and it is obvious that the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example 1

Fig. 1, 2 and 3 show a crimping device according to the invention in a side view, an exploded view and a perspective sectional view, respectively. The crimping device comprises an insert 1 and a sleeve 2 for connecting a first hollow tube 3 and a second hollow tube 4. Wherein, the first hollow pipe 3 is a metal pipe, and the second hollow pipe 4 is a plastic composite pipe. The insert 1 and the sleeve 2 are made of steel. The inner and outer surfaces of the sleeve 2 are smooth and are plated with zinc and nickel and are passivated transparently. The plastic composite tube comprises an inner tube 41 of plastic and an outer layer 42 of wrapped braid (see fig. 3). The plastic inner tube 41 is made of PTFE (polytetrafluoroethylene, commonly known as teflon), and the circumferential surface of the plastic inner tube is formed with a screw thread. The outer layer 42 of the braid is a steel wire braid.

One side of the insert 1 is fixedly connected to the metal tube by welding. Starting from this connection side, the insertion part 1 has a first projection 111, a latching groove 113, a second projection 112 and an insertion section 12 in this order. The axial width of the first boss 111 is 15mm and the diameter of the outer peripheral surface thereof is 33mm, and the axial width of the second boss 112 is 2.5mm and the diameter of the outer peripheral surface thereof is 30.8 mm.

One end of the sleeve 2 is formed as a radially inwardly L-shaped annular catch 21 (see fig. 3). During assembly, the sleeve 2 is first inserted into the insert 1 from the insertion section 12 with one end of the catch 21. The inner diameter of the circumference of the catch 21 of the sleeve 2 is here 31 mm. Therefore, the catch 21 passes over the second boss 112 upon insertion until abutting against the end face of the first boss 111. The other end of the sleeve 2 opposite the catch 21 is shaped as a flared radially outwardly expanding section 23. The wall thickness of the expansion section 23 is uniform and thinner than the rest of the sleeve. The circumferential outer surface of the sleeve 2 has two circumferential crimping grooves, wherein the first crimping groove 221 adjoins the snap 21 and the second crimping groove 222 adjoins the expansion section 23. As can be seen in fig. 3, the radial depth of the two crimping grooves varies in the axial direction, and the radial deepest of both crimping grooves corresponds to the extent of the insertion section 12 of the insert 1.

The intermediate section 24 is defined between the first crimping groove 221 and the second crimping groove 222 of the sleeve 2. As is clear from fig. 2 and 3, the wall thickness of the intermediate section 24 of the sleeve 2 is greater than the wall thickness of the expanding section 23, the first crimping groove 221 and the second crimping groove 222.

As is clear from fig. 2, the outer surface of the insertion section 12 of the insert 1 is tapered, with a minimum outer diameter of the taper of 24.9mm at the end remote from the first and second bosses 111, 112 and a maximum outer diameter of the taper of 27.3mm abutting the end face of the second boss 112. The angle of the taper is 2 °. The axial length of this conical insertion section is 35mm, while the axial length of the remaining part of the sleeve 2, excluding the L-shaped catches 21, is 32.5mm, so that after the sleeve 2 has been slipped over the insert 1 and stopped on the end face of the first projection 111, the end of the insert 1 remote from the projection projects slightly beyond the end of the expansion section of the sleeve 2 (see fig. 3).

After the sleeve 2 has been inserted into the insert 1, the plastic composite pipe is inserted from the tapered end with the smallest outer diameter into the gap enclosed between the insert 1 and the sleeve 2 until the end face abuts against the end face of the second projection 112 of the insert 1. Since the insertion section 12 is shaped as a cone, the end face of the plastic composite pipe is located at the maximum outer diameter of the cone and thus has an interference fit with the inner wall of the sleeve 2 and the outer wall of the insert 1, while as the outer diameter of the cone decreases, a slight clearance is created between the plastic composite pipe and the inner wall of the sleeve 2 and the outer wall of the insert 1.

After the plastic composite pipe is inserted between the sleeve 2 and the insert 1, an extrusion die (not shown) is used on the outside of the sleeve 2, which is assembled from 8-segment dies into a cylinder, surrounds the radially outer portion of the sleeve 2, and applies a radially inward pressure thereto. By this pressing process, the catch 21 of the sleeve 2 is brought into contact with the bottom of the catch groove 113 of the insert 1. Here, the catch 21 and the catch 113 both have a square longitudinal cross section and are form-fit to one another, thereby fixing the sleeve 2 and the insert 1 to one another; on the other hand, the plastic inner tube of the plastic composite tube is deformed during the extrusion process, and the plastic material flows along the gap between the sleeve 2 and the insert 1 by extrusion and is thus tightly radially crimped between the sleeve 2 and the insert 1. In addition, the first buckling groove 221 and the second buckling groove 222 of the sleeve are not in direct contact with the cylindrical inner surface of the extrusion die due to the radial inward concavity, so that the force applied to the two buckling grooves is reduced, resulting in that the stress applied to the end portions of the plastic composite pipes corresponding to the radial inner portions is not too large.

In this embodiment, the intermediate section 24 of the sleeve 2 has a circumferential outer surface diameter of 40mm before extrusion through the die and a reduction of 35.2mm after extrusion through the die. In this compressed condition of the outer diameter, the insert 1 is very strong against deformation, whereby a very large buckling force can be effectively created between the insert 1 and the plastic composite pipe and the sleeve 2. No adhesive is required in the whole crimping device.

Additionally, during extrusion, the outer surface material of the sleeve 2 may be partially deformed into the gaps between the respective flap molds, thereby longitudinally forming projecting ribs circumferentially spaced from one another on the outer surface.

Example 2

This embodiment is substantially identical to embodiment 1 in structure, and reference is made specifically to the description of embodiment 1 above.

Unlike embodiment 1, the outer circumferential surface diameter of the first boss 111 is 39.5mm, and the outer circumferential surface diameter of the second boss 112 is 37.2 mm. The inner surface diameter of the catch 21 of the sleeve 2 is 38.6 mm.

The insert section 12 of the insert 1 has a minimum outer diameter of 31.3mm in the taper and a maximum outer diameter of 33.7mm in the taper. The angle of the taper is 2 °.

In this embodiment, the intermediate section 24 has a circumferential outer surface diameter of 48.7mm prior to die extrusion and a reduction of 41.3mm after die extrusion. In this compressed condition of the outer diameter, the strength of the insert 1 against deformation is also very great, whereby a very great buckling force can be effectively created between the insert 1 and the plastic composite pipe and the sleeve 2. No adhesive is required in the whole crimping device.

It is to be understood that the above embodiments are merely exemplary embodiments that have been employed to illustrate the principles of the present invention, and that the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Description of the reference numerals

1 insert piece

12 insertion section

111 first boss

112 second boss

113 card slot

2 sleeve

21 fastener

23 expansion section

24 middle section

221 first buckling groove

222 second crimping groove

3 the first hollow pipe

4 second hollow pipe

41 inner pipe

42 outer layer

Claims (13)

1. A crimping device for connecting hollow tubes, the crimping device comprising:

the insert (1) comprises a connecting section for connecting a first hollow tube (3) and an inserting section (12) for inserting a second hollow tube (4), the insert (1) is provided with a first boss (111) and a second boss (112) at the connecting section, and a clamping groove (113) is formed between the first boss (111) and the second boss (112);

a sleeve (2), said sleeve (2) having an annular snap (21) projecting radially inwards;

wherein, when the sleeve (2) is mounted onto the insertion section (12) of the insert (1), the catch (21) is press-fitted into the catch (113) of the insert (1) in a form-fitting manner and the second hollow tube (4) is radially compressed between the insertion section (12) of the insert (1) and the sleeve (2);

characterized in that the wall thickness of the end portions of the sleeve (2) is smaller than the wall thickness of the middle portion.

2. Crimping device according to claim 1, characterized in that the outer circumferential surface of the sleeve (2) has a circumferential crimping recess.

3. Crimping device according to claim 1, characterized in that the first boss (111) is axially wider than the second boss (112), the outer diameter of the first boss (111) being larger than the outer diameter of the second boss (112).

4. Crimping device according to one of claims 1 to 3, characterized in that the sleeve (2) has a radially outward expansion section (23), from which expansion section (23) the second hollow tube (4) is inserted between the sleeve (2) and the insert (1).

5. Crimping device according to claim 4, characterized in that the wall thickness of the expansion section (23) is uniform.

6. Crimping device according to claim 4, characterized in that the outer circumferential surface of the sleeve (2) is provided circumferentially and at intervals with at least two crimping grooves, the radial deepest of which corresponds to the extent of the insertion section (12) of the insert (1).

7. Crimping device according to claim 6, characterized in that of the at least two crimping grooves, a first crimping groove (221) and a second crimping groove (222) define between them an intermediate section (24), the intermediate section (24) being thicker than the expansion section (23) and the at least two crimping grooves.

8. Crimping device according to one of claims 1 to 3, characterized in that the connection section and the insertion section both project axially beyond the sleeve (2).

9. Crimping device according to one of claims 1 to 3, characterized in that the second hollow tube (4) is a plastic composite tube, the second hollow tube (4) comprising an inner tube (41) of plastic and an outer layer (42) of braid.

10. Crimping device according to claim 9, characterized in that the inner tube (41) is a PTFE inner tube and the outer layer (42) is a steel braid.

11. Crimping device according to claim 9, characterized in that the inner tube (41) has a spiral shape.

12. Crimping device according to one of claims 1 to 3, characterized in that the first hollow tube (3) is a metal tube, the insert (1) and the first hollow tube (3) being connected by welding or being integrally formed.

13. Crimping device according to one of claims 1 to 3, characterized in that the insert (1) and the sleeve (2) consist of steel.

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