KR100859542B1 - Dual tube structure for shock absorber with damping force variable and method for manufacturing the same - Google Patents

Abstract

A dual tube structure for a damping force variable type shock absorber and a method for manufacturing the same are provided to improve reliability and durability of the dual tube structure through eliminating O-ring press fitting and swaging processes. A dual tube structure(100) for a damping force variable type shock absorber comprises a first metal tube(110) to receive a piston, a second metal tube(120) surrounding the first metal tube while being spaced apart from each other, and a brazing portion formed by heating a filler metal interposed between the first metal tube and the second metal tube. The second metal tube includes a narrower tube portion(122) having a smaller diameter portion at the middle part of the second metal tube. The brazing portion includes a brazing partition wall formed by heating the filler metal between the narrower tube portion of the second metal tube and an outer peripheral surface of the first metal tube.

Description

DUAL TUBE STRUCTURE FOR SHOCK ABSORBER WITH DAMPING FORCE VARIABLE AND METHOD FOR MANUFACTURING THE SAME}

1 is a cross-sectional view showing a damping force variable shock absorber according to the prior art.

Figure 2 is a cross-sectional view partially showing a double pipe structure of a damping force variable shock absorber according to an embodiment of the present invention.

Figure 3 is a cross-sectional view for explaining the double pipe structure of the damping force variable shock absorber according to another embodiment of the present invention.

4 shows a continuous brazing device that may be used to make a double tube structure.

5 is a flow chart illustrating a method of manufacturing a double pipe structure according to the present invention.

6 and 7 are views for explaining the structure of the second tube for easily forming the partition partition wall in other embodiments of the present invention.

<Code Description of Main Parts of Drawing>

100: double tube structure 110: the first metal tube

120: second metal tube 122, 123: shaft pipe portion

150: brazing junction 140: brazing bulkhead

The present invention relates to a damping force variable shock absorber having a variable damping force valve, and more particularly, a damping force variable shock absorber defining a space in which a piston is accommodated inside and a flow path connected to the damping force variable valve outside. It relates to the double tube structure of.

Generally, a shock absorber used for a suspension device of a vehicle is provided between an axle and a vehicle body to absorb vibrations or shocks received from the road surface while driving the vehicle, and to improve ride comfort. Or gas is filled.

Such a shock absorber has a damping force variable shock absorber that can adjust the damping force characteristics appropriately to improve ride comfort or steering stability according to the road surface and driving conditions.

Referring to Figure 1, the conventional damping force variable shock absorber will be described as follows.

As shown in FIG. 1, the conventional damping force variable shock absorber is installed inside the base shell 20 while the inner tube 10 is supported by the rod guide 11 and the body valve 12 at both ends. A storage chamber (V) filled with gas and oil is formed between the inner tube 10 and the base shell 20 at the boundary of the body valve 12.

While the oil is filled in the inner tube 10, the piston 60 coupled to the lower end of the piston rod 62 is slidably received. By the piston 60, the inner space of the inner tube 10 is divided into a compression chamber C and a tension chamber R. The inner tube 10, together with the separator tube 30 spaced apart from its outer circumferential surface, forms a double tube structure that defines a flow path communicating with the damping force variable valve 70.

The flow path 32 between the separator tube 30 and the inner tube 10 is separated into upper and lower flow paths 32a and 32b by a partition structure 40 formed of a sealing and support ring, and the upper and lower flow paths 32a and 32b. Are each through the tension chamber (R) and the compression chamber (C) in the inner tube (10) through the holes (17, 18) formed in the inner tube (10). Each of the upper and lower flow paths 32a and 32b is connected to the tension oil port 72 and the compressed oil port 74 of the damping force variable valve 70 provided outside the base shell 20, respectively.

In the conventional damping force variable shock absorber, the means 50 for combining the inner tube 10 and the separator tube 30 to form a double tube structure will be described with reference to the enlarged view of FIG. 1. Referring to the enlarged view of FIG. 1, the means 50 includes an O-ring 52 press-fitted to the inner circumferential surface of the separator tube 30 and groove rings 51a and 51b for supporting the O-ring 52 up and down. do. The grooves 51a and 51b have annular grooves G formed on the outer circumferential surface thereof, and the grooves G engage the protrusions S formed by swaging or caulking the separator tube 30 to form an inner tube. 10) and the separator tube 30 is firmly fixed.

However, in the conventional damping force variable shock absorber, foreign matters generated during the indentation of the groove rings 51a and 51b or the o-ring 52 are likely to remain in the separator tube 30, and the above complicated indentation process and swaging ( Or caulking) process is necessary in that the manufacturing process is complicated. In addition, the upper groove rings 51a, 51b and the o-ring 52 have a high possibility of failure and breakage, making it difficult to manufacture a reliable shock absorber.

Accordingly, there is a need in the art for a double tube structure that can function as a separator tube of a damping force variable shock absorber and as an inner tube without the installation of grooves and O-rings.

The technical problem of the present invention is to provide a reliable and reliable method including the function of the separator tube and the inner tube function by using a simple brazing process that eliminates the conventional indentation process and the swaging (or caulking) process of the grooving or O-ring. It is to manufacture double pipe structure of durable damping force variable shock absorber.

According to an aspect of the invention, there is provided a double pipe structure of the damping force variable shock absorber that defines a space in which the piston is accommodated inside, and defines a flow path connected to the damping force variable valve from the outside, the double pipe structure, Formed by heating a first metal tube for receiving, a second metal tube surrounding the first metal tube in a spaced apart state, and a filler material interposed between the first metal tube and the second metal tube; It includes a brazing part. As used herein, the term “brazing portion” refers to a portion formed by brazing welding, and is used in the sense of including both the brazing junction portion and the brazing partition portion described below.

Preferably, the second metal tube has a reduced diameter shaft tube portion near an end portion, and the brazing portion heats the filler metal between the shaft tube portion of the second metal tube end portion and the outer circumferential surface of the first metal tube. It is a brazing joint formed by this, The said brazing joint joins the said 1st metal tube and the said 2nd metal tube, and by the joining, the said flow path is limited between the said 1st metal tube and the said 2nd metal tube.

Preferably, the second metal tube includes a shaft portion having a reduced diameter in the middle portion, and the brazing portion heats the filler metal between the shaft portion in the middle of the second metal tube and the outer circumferential surface of the first metal tube. And a brazing partition wall portion, the brazing partition wall partitioning the flow path between the first metal tube and the second metal tube up and down. In this case, a hole or a gap is formed in the shaft tube portion in the middle of the second metal tube to apply the filler material to fill the gap between the first metal tube and the second metal tube.

According to another aspect of the present invention, there is provided a method for manufacturing a double pipe structure of a damping force variable shock absorber that defines a space in which the piston is accommodated inside, and a flow path connected to the damping force variable valve in the outside. The method includes the steps of preparing a first metal tube and a second metal tube having a diameter and shorter length than the first metal tube, and positioning the second metal tube to be spaced apart from the first metal tube. And the step of heating the filler metal interposed between the first metal tube and the second metal tube.

Other objects and advantages of the invention will be more clearly understood from the following description of the examples.

2 is a partial view of a double pipe structure of a damping force variable shock absorber according to an embodiment of the present invention. Referring to FIG. 2, the double tube structure 100 of the present embodiment includes a first metal tube 110, a second metal tube 120, and a brazing joint 150. The first metal tube 110 is a portion that slidably accommodates the piston 60 (see FIG. 1), and the second metal tube 120 is a flow path connected to the damping force variable valve 70 (see FIG. 1). It is a part defining 130. The flow path 130 passes through the inside of the first metal tube 110 by a hole 117 formed in the first metal tube 110, and a damping force variable valve 70 is provided in the second metal tube 120. A port connecting portion 127 connected to the compression or tension port of FIG. 1).

The second metal tube 120 is positioned to surround the periphery of the first metal tube 110 to have a larger diameter than the first metal tube 110 in order to define the flow path 130. In addition, the second metal tube 120 includes a shaft tube portion 122 having a reduced diameter compared to the other portion near the end portion, and an inner circumferential surface of the shaft tube portion 122 and an outer circumferential surface of the first metal tube 110. The brazing junction 150 is formed in a minute gap therebetween.

The brazing joint 150 is formed by heating a metal filler at 450 ° C. or higher according to its type, and bonding and fixing the second metal tube 120 to the first metal tube 110. It serves to seal the flow path defined between the first metal tube 110 and the second metal tube 120 to the outside. The filler metal may be selected in consideration of the wettability, strength, and oil tightness with the materials of the first and second metal tubes 110 and 120 which are the base materials. Examples of the filler metal include Al lead material, in order of melting temperature. Ag lead, copper lead, brass lead, Au lead, Ni lead, Palladium lead and the like can be used. In addition, as the brazing welding method for forming the brazing joint 150, a method of heating the filler metal under a brazing atmosphere (hydrogen or vacuum atmosphere) of the brazing furnace (brazing furnace), which is the double pipe structure 100 Suitable for mass production of

The shaft portion 122 may be formed in advance before the second metal tube 120 is positioned to surround the periphery of the first metal tube 110, but preferably, the second metal tube 120 Is positioned by surrounding the periphery of the first metal tube 110, by any shaft tube processing (ie, reducing the tube diameter). The filler metal applied to a portion of the first metal tube 110 or the second metal tube 120 in the form of a paste may be in contact with each of the two metal tubes 110 and 120.

If the flow path 130 is to be separated up and down using the conventional barrier rib structure 40 (see FIG. 1), the brazing joint 150 is formed at one end of the second metal tube 120, or, Before forming the brazing junction 150, the flow path 130 may be separated up and down using the partition structure. In addition, as described below, only when the flow path 130 is vertically separated by welding using brazing, the vertical separation of the flow path 130 and the formation of the brazing joint 150 may be performed at the same time. .

3 is a cross-sectional view of the double pipe structure 100 of the damping force variable shock absorber according to another embodiment of the present invention as a whole.

Referring to FIG. 3, in the vicinity of both ends of the second metal tube 120, the brazing joint 150 may be formed by the bonding between the first metal tube 110 and the second metal tube 120 and the flow path 130. Used for sealing. Since the brazing joint 150 has been described in detail above, a detailed description thereof will not be provided. The double pipe structure 100 according to the present embodiment further includes a brazing partition wall part 140 for vertical separation of the flow path 130.

The brazing partition wall 140 is formed by brazing a filler material interposed between the first metal tube 110 and the second metal tube 120 in the middle portion of the second metal tube 120. Furthermore, the second metal tube 120 includes a shaft tube portion 123 at a portion where the brazing partition wall 140 is positioned, and the shaft tube portion 123 includes tubes 110 and 120 having filler metal interposed therebetween. By narrowing the gap between the), even the small thickness of the brazing partition wall 140 enables the reliable vertical separation of the flow path 130.

When the brazing furnace is used, filler metals interposed at respective positions between the tubes 110 and 120 may be heated in the brazing furnace so that the brazing junction 150 and the brazing partition wall 140 may be simultaneously formed.

FIG. 4 shows a continuous brazing device comprising a brazing furnace for use in the manufacture of the double pipe structure described above.

Referring to FIG. 4, the continuous brazing apparatus 300 includes a conveying conveyor 310 carrying a plurality of charges including first and second metal tubes 110 and 120 interposed with filler metal, and the conveying. It includes a brazing furnace 320 for heating the charges carried on the conveyor 310 to a brazing temperature under a hydrogen atmosphere or a vacuum, and cooling means 330 for cooling the charges from the brazing furnace 320. do. The transfer conveyor 310 is preferably a mesh belt conveyor made of a high melting point metal. In addition, the brazing furnace 320 may include a gas curtain that is installed at the inlet and the outlet thereof to isolate the internal atmosphere from the outside, and means for forming the interior of the furnace in a vacuum or hydrogen atmosphere.

 Using the continuous brazing apparatus 300 as described above, the flow path 130 is sealed by the brazing joint 150 as shown in Figure 3 and the flow path 130 is up and down by the brazing partition wall 140 The double pipe structure 100 separated into can be easily manufactured in large quantities.

5 is a flowchart illustrating a method of manufacturing the double pipe structure 100 according to the present invention. 2 to 5, in particular, referring to FIG. 5, the manufacturing method includes preparing a first and second metal tubes 110 and 120 (S101) and bonding the prepared metal tubes 110 and 120. Positioning and interposing the filler material between the metal tube (110, 120) (S102), and heating the interposed filler material (S103).

In step S101, the second metal tube 120 is prepared to have a larger diameter and shorter length than the first metal tube 110. In step S102, the second metal tube 120 is positioned to surround the first metal tube 110, and at that position, a gap between the first metal tube 110 and the second metal tube 120. In some, filler material on a paste is interposed. When the shaft tube portion 122 and / or 123 is provided in the second metal tube 120, the shaft tube portion may be formed in advance in step S101, or may be formed after the filler material is inserted in step S102. Then, brazing welding for heating the filler metal to 450 ° C. or higher is performed in step S103, whereby the brazing joint 150 and / or the brazing partition 140 are placed in the gap between the tubes 110, 120. Is formed.

Instead of the brazing partition wall 140, the existing partition wall structure 40 shown in FIG. 1 may be employed. However, when using the brazing barrier rib portion 140, the brazing junction portion 150 and the brazing barrier rib portion 140 may be formed at once by the above-described steps (S101, S102, S103).

6 and 7 are views for explaining the structure of the second tube 120 suitable for forming the aforementioned brazing partition wall 140.

First, referring to FIG. 6, it can be seen that a plurality of holes 1232 are formed along the circumferential direction of the shaft tube part 123 in the middle of the second tube 120. These holes 1232 are for easily applying or filling filler material for the formation of the brazing compartment 140 (see FIG. 3) between the first tube 110 and the second tube 120. These holes 1232 are blocked by the brazing partition wall portion 140 formed by heating the filler metal, so there is no fear of oil leakage through the holes 1232.

Next, referring to FIG. 7, it can be seen that one gap 1234 formed entirely along the circumferential direction is formed in the shaft tube part 123 in the middle of the second tube 120. The gap 1234 is formed between the upper tube body 120a and the lower tube body 120b when the second tube 120 is formed of the upper and lower tube bodies 120a and 120b separated from each other in the shaft tube part 123. Is formed. By applying the filler material through the gap 1234, the filler material is interposed between the first tube 110 and the second tube 120, and then the filler material is heated, thereby forming the brazing partition wall 140 (FIG. 3). The gap 1234 is filled by the brazing partition wall 140. At this time, the brazing partition wall 140 may connect the upper tube body 120a and the lower tube body 120b integrally.

While the invention has been described above with reference to specific embodiments, various modifications, changes or modifications may be made in the art within the spirit of the invention and the appended claims, and thus, the foregoing description and drawings It should be construed as illustrating the present invention rather than limiting the technical spirit of the present invention.

According to an embodiment of the present invention, since a conventional brazing or o-ring press and a brazing process can be omitted, the residues in the shock absorber during indentation of the groove ring or O-ring are omitted. The brazing process is simple, and can greatly contribute to reducing the overall manufacturing cost of the damping force variable shock absorber. In addition, the double pipe structure manufactured according to the embodiment of the present invention contributes to the production of reliable and durable damping force variable shock absorber.

Claims (5)

delete delete In the double pipe structure of the damping force variable shock absorber that defines a space in which the piston is accommodated inside, and defines a flow path connected to the damping force variable valve in the outside, A first metal tube for receiving the piston; A second metal tube surrounding the first metal tube in a spaced state; It includes a brazing portion formed by heating the filler metal interposed between the first metal tube and the second metal tube, The second metal tube includes a shaft portion having a reduced diameter in the middle portion, and the brazing portion is formed by heating the filler metal between the shaft portion in the middle of the second metal tube and the outer circumferential surface of the first metal tube. And a partition wall portion, wherein the brazing partition wall partitions the flow path between the first metal tube and the second metal tube up and down to define a partition of the shock absorber. The double tube of the shock absorber according to claim 3, wherein a hole or a gap is formed in the shaft tube portion in the middle of the second metal tube to fill the filler metal and fill the gap between the first metal tube and the second metal tube. structure. delete

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