JP5013255B2 - Cylinder device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylinder device such as a hydraulic shock absorber, a gas spring, and a hydraulic cylinder, and a manufacturing method thereof.

  For example, a hydraulic shock absorber for an automobile is usually interposed between a vehicle body and an axle using a bolt-shaped mounting member provided at the tip of the piston rod and an annular mounting eye provided at the bottom of the outer tube. Is done. In this case, the mounting eye is often directly connected to the bottom of the outer tube, but may be connected to the bottom of the outer tube via a bar-like member in relation to the peripheral device. Therefore, in this case, the whole including the rod-shaped member and the mounting eye is a hydraulic shock absorber (cylinder device).

  Conventionally, the connecting structure between the rod-shaped member and the mounting eye in the above-described cylinder device has been a structure in which the outer peripheral surface of the mounting eye is welded by arc welding with high welding strength. However, in such a joining structure, arc welding is performed in a state where the end surface of the rod-shaped member is abutted against the outer peripheral surface (curved surface) of the annular mounting eye, that is, in a line contact state, so that the penetration depth of the rod-shaped member is It varies greatly in the circumferential direction, and it has been extremely difficult to obtain a weld bead having a uniform size (thickness). Further, due to the instability of the weld bead in the circumferential direction described above, there is a problem that depending on the part, the periphery of the weld bead becomes a stress concentration part (edge) and causes a decrease in fatigue strength. For example, although the weld strength of the welded portion is sufficient, the mounting eye itself may crack in the radial direction from the periphery of the weld bead, resulting in fatigue failure.

In addition, although it is related with the ball joint apparatus for compressors, in patent document 1, as shown in FIG. 5, the flat part 2 is formed in the outer peripheral surface of the ring-shaped member 1, and the ball joint 3 which is a rod-shaped member is described above. A technique for performing electrical resistance welding by abutting against the flat portion 2 is disclosed.
Japanese Patent Laid-Open No. 2-80175

  However, in the technique described in Patent Document 1, since the outer peripheral surface of the ring-shaped member 1 is simply the flat portion 2, the thickness of the portion where the flat portion 2 is formed is thinner than other general portions, When it is applied to a cylinder device mounting device that is subjected to a large load as in the present invention, there remains an uneasy strength.

  The present invention has been made in view of the above-described technical background, and the problem is that it is possible to stably form a uniform weld bead in the circumferential direction without causing a decrease in strength. An object of the present invention is to provide a cylinder device and a manufacturing method thereof.

In order to solve the above problems, a cylinder device according to the present invention includes an outer tube, a rod-like member having one end joined to the bottom of the outer tube, and an annular mounting eye joined to the other end of the rod-like member. The rod-shaped member and the mounting eye are arc-welded with the outer peripheral surface of the mounting eye as a joint, and the rod-shaped member has a smaller diameter than the outer tube and has the other end of the rod-shaped member. is a convex shape, said inner mounting eye is circular, with the outer generally portion forming a thick portion for thickness Ku partially than the junction between the other end of the rod-like member, the thick portion wherein subjected to bonding with the rod-like member to form a flat surface, the flat surface only the other end an open welding an annular gap formed by abutting on the flat surface of the mounting eye of the rod-like member as a bonding surface Ahead Characterized in that it can use this in.

  In the cylinder device configured as described above, a flat surface formed on the outer peripheral surface of the mounting eye is used as a joint portion with the rod-shaped member, so that a welding beat having a uniform size in the circumferential direction of the rod-shaped member can be stably provided. Can be formed. Further, since the flat surface is formed in the thick part provided in the mounting eye, the strength is not weakened.

  In this cylinder apparatus, it can be set as the structure which has arrange | positioned the connection part which thickness increases continuously from a general part to the thick part side between the general part and the thick part of the said attachment eye. In this case, the stress concentration portion is not formed on the mounting eye, so that the anxiety in terms of fatigue strength is reliably eliminated.

The method for manufacturing a cylinder device according to the present invention for solving the above-described problem is a method for manufacturing the cylinder device according to claim 1 or 2, wherein the other end of the rod-shaped member that is a connection end to the mounting eye. Is formed in a convex shape, the other end of the rod-shaped member is abutted against the flat surface of the mounting eye, and only the flat surface is used as a joint surface, and in this state, the connecting end of the rod-shaped member and the flat surface of the mounting eye Arc welding is performed by utilizing the inside of the annular gap formed between the two as a welding groove.

In the method of manufacturing the perform cylinder device, a utilizing arc welding an annular gap formed by abutting the other end of the bar-like member formed into a convex shape on the flat surface of the mounting eye as welding groove As a result, the bonding interface between the rod-shaped member and the mounting eye is greatly enlarged, and the bonding strength is sufficient.

In this manufacturing method, by performing the projection welding in a state that had abutting convex shape of the connecting end of said rod member on the flat surface of the mounting eye, after preliminarily bonding the mounting eye and rod-shaped member Further, arc welding may be performed in an annular gap formed between the two. In this case, the subsequent arc welding can be performed easily and with high accuracy by preliminarily joining the rod-shaped member and the mounting eye by projection welding.

  According to the cylinder device and the manufacturing method thereof according to the present invention, it is possible to stably form a uniform weld bead in the circumferential direction without causing strength instability. It is possible to realize a highly reliable device and is extremely useful as a cylinder device that receives a high load.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows the overall structure of a cylinder device according to the present invention. The cylinder device includes a rod-like member 11 having one end joined to the bottom of the outer tube 10 of the hydraulic shock absorber and an annular mounting eye 12 joined to the other end of the rod-like member 11. The rod-shaped member 11 and the mounting eye 12 are arc welded with the outer peripheral surface of the mounting eye 12 as a joint, and a weld bead 13 by arc welding is disposed between the two. The rod-shaped member 11 has a cup-shaped receiving portion 14 provided at one end thereof fitted to the bottom portion of the outer tube 10, and the mouth edge portion 14 a of the receiving portion 14 is in contact with the outer peripheral surface of the outer tube 10. All-around welding (arc welding) is performed.

  In this embodiment, the other end (joining end) of the rod-shaped member 11 to be joined to the mounting eye 12 is formed with a convex-shaped convex portion 15 as shown in FIG. As shown in FIG. 3, a flat surface 16 is formed at the joint portion of the mounting eye 12 to be joined. In arc welding, as shown in FIG. 4, the convex portion 15 at the joint end of the rod-shaped member 11 is abutted against the flat surface 16 of the mounting eye 12, and in this state, between the rod-shaped member 11 and the mounting eye 12. Arc welding (full circumference welding) is performed using the annular gap 17 formed. Therefore, the weld bead 13 (FIG. 1) is formed over the entire circumference of the rod-shaped member 11.

  The attachment eye 12 is configured as a thick portion 12b where the joint portion with the rod-shaped member 11 is thicker than the general portion 12a, and the flat surface 16 is formed in the thick portion 12b. Even if the thick portion 12a has an area S {shown by dotted hatching in FIG. 3 (A)} necessary for joining to the rod-like member 11 as the flat surface 16, the thick portion 12a still has the meat of the general portion 12a. The thickness is set such that a minimum thickness t2 (t2 ≧ t1) equal to or greater than the thickness t1 remains on the bottom side of the flat surface 16. Further, the connecting part 12c between the thick part 12b and the general part 12a has a shape in which the thickness is continuously increased from the general part 12a to the thick part 12b. A corner R of a predetermined size is attached to the connecting corner between the portion 12 b and the flat surface 16.

  In the cylinder device configured as described above, since the flat surface 16 formed on the outer peripheral surface of the mounting eye 12 is used as a joint portion with the rod-shaped member 11, the size of the rod-shaped member 11 is uniform in the circumferential direction. The welding beat 13 can be formed stably. This eliminates stress concentration points (edges) from around the weld bead 13 and suppresses a decrease in fatigue strength. Further, since the flat surface 16 used for joining with the rod-shaped member 11 is formed in the thick portion 12b of the mounting eye 12, the mounting eye 12 itself does not weaken in strength, and has strong reliability. It becomes a thing with high property. Furthermore, since the attachment eye 12 has a thick portion 12b only at the joint portion with the rod-shaped member 11 and its periphery, the width W {FIG. 3A} in the direction perpendicular to the axis of the outer tube 10 is enlarged. No, the hydraulic shock absorber can be easily attached to the vehicle body even when the installation space is limited.

  Particularly in the present embodiment, a connecting portion 12c that continuously increases the thickness from the general portion 12a to the thick portion 12b is arranged between the general portion 12a and the thick portion 12b of the mounting eye 12. Therefore, the stress concentration portion is reliably eliminated from the periphery of the weld bead 13, and as a result, the anxiety in terms of fatigue strength is surely eliminated.

  The rod-shaped member 11 and the mounting eye 12 described above can be manufactured by forging, but the convex portion 15 at the joining end of the rod-shaped member 11 and the inner diameter of the mounting eye 12 are finished by machining. In manufacturing the cylinder device, as shown in FIG. 4, the convex portion 15 at the connection end of the rod-shaped member 11 is abutted against the flat surface 16 of the mounting eye 12, and in this state, the rod-shaped member 11 and the mounting eye 12. Arc welding (circumferential welding) is performed using an annular gap 17 formed between the top and the projection 15 of the rod-shaped member 11 and the flat surface 16 of the mounting eye 12 by projection welding. Thus, both may be preliminarily joined. In this case, since the rod-shaped member 11 and the mounting eye 12 are fixed to each other by preliminary joining, the subsequent arc welding can be performed easily and with high accuracy.

  Further, by providing the convex portion 15, the following problems can be solved in the projection welding. That is, when the joining end of the rod-shaped member 11 is a flat surface, if the direction of abutting against the flat surface 16 of the mounting eye 12 is slightly inclined, the way of contact becomes uneven. Then, since the projection welding is welded by melting the contacted portion, the welded portion becomes non-uniform. However, by providing the convex portion 15, even if it is slightly tilted, only one point melts, so that a uniform weld is formed.

  In the above embodiment, the convex portion 15 at the joint end of the rod-shaped member 11 has a convex shape, but it goes without saying that this convex portion may have a cone shape (weight shape).

It is a side view which shows the whole structure of the cylinder apparatus which concerns on this embodiment. It is a side view which shows the shape of the rod-shaped member which comprises this cylinder apparatus as a partial cross section. The shape of the mounting eye which comprises this cylinder apparatus is shown, (A) is a top view, (B) is a front view, (C) is sectional drawing which follows the XX arrow line of (B). It is a side view which shows the positioning state before joining with the rod-shaped member and attachment eye which comprise this cylinder apparatus. It is a side view which shows the conventional joining structure in the junction part of a rod-shaped member and a ring-shaped member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer tube 11 Rod-shaped member 12 Mounting eye 12a General part of mounting eye 12b Thick part of mounting eye 12c Connecting part of mounting eye 13 Welding bead 15 Convex-shaped convex part of rod-shaped member 16 Flat surface of mounting eye

Claims (4)

An outer tube, a rod-shaped member having one end joined to the bottom of the outer tube, and an annular mounting eye joined to the other end of the rod-shaped member, and the rod-shaped member and the mounting eye are In the cylinder apparatus that is arc-welded with the outer peripheral surface as a joint, the rod-shaped member has a smaller diameter than the outer tube , the other end of the rod-shaped member has a convex shape, the inside of the mounting eye is circular, and the outside is wherein while the general section forming a thick portion for thickness Ku partially than the junction between the other end of the rod, to form a flat surface to be subjected to bonding with the rod-like member in the thick portion, wherein cylinder device which is characterized by utilizing an annular gap formed by abutting the other end of the rod-shaped member to the flat surface of the mounting eye only flat surface as a bonding surface as welding groove.   The cylinder device according to claim 1, wherein a connecting portion that continuously increases in thickness from the general portion to the thick portion side is disposed between the general portion and the thick portion of the mounting eye. It is a method of manufacturing the cylinder apparatus according to claim 1 or 2, wherein the other end of the rod-shaped member that is a connection end to the mounting eye is formed in a convex shape, and the other end of the rod-shaped member is made flat on the mounting eye. Arc welding using the annular gap formed between the connecting end of the rod-shaped member and the flat surface of the mounting eye in this state as a welding groove. The manufacturing method of the cylinder apparatus characterized by performing.   Projection welding is performed in a state in which the convex-shaped or cone-shaped connection end of the rod-shaped member is abutted against the flat surface of the mounting eye, and the rod-shaped member and the mounting eye are preliminarily joined, and then between the two The method for manufacturing a cylinder device according to claim 3, wherein arc welding is performed in an annular gap formed in the cylinder.

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