JP5844568B2 - Grooving method for rod-shaped member - Google Patents

Description

  The present invention relates to a groove processing method for a rod-shaped member that forms a circumferential groove on the outer peripheral side of a rod-shaped member such as a piston rod of a hydraulic shock absorber.

  A hydraulic shock absorber provided in a traveling apparatus such as an automobile includes a cylinder having a piston and a piston rod having one end connected to the piston in the cylinder and the other end protruding in a telescopic manner from the cylinder via a rod guide. It is roughly structured. An annular stopper is attached at an intermediate position in the axial direction of the piston rod so as to be positioned on the outer peripheral side. The stopper abuts against the rod guide when the piston rod is extended, thereby defining the maximum extension position of the piston rod.

  In this case, a circumferential groove is formed on the outer circumferential surface of the piston rod, and a stopper is fixed to the piston rod by so-called metal flow coupling in which a part of the stopper is plastically deformed and pushed into the circumferential groove.

  Here, the groove processing device for processing the circumferential groove on the outer circumferential surface of the piston rod is composed of a plurality of rolling rollers having circumferential projections on the outer circumferential side, and the rolling rollers are rotated while being arranged in parallel. A circumferential groove is machined on the outer circumferential surface of the piston rod by pressing the circumferential projection on the outer circumferential side against the piston rod disposed between the rolling rollers (see, for example, Patent Document 1).

  The grooving apparatus has a positioning member that contacts the end of the piston rod when the piston rod is disposed at a correct position in the axial direction, and a pressing member that presses the piston rod against the positioning member. . As a result, in a state where the piston rod is sandwiched between the positioning member and the pressing member, the piston rod can be disposed at the correct axial position, and the entire circumferential groove can be processed to an accurate position.

JP 2003-254436 A

  At the time of grooving, the piston rod is sandwiched and fixed in the axial direction by the positioning member and the pressing member so that the piston rod is not displaced in the axial direction. In the grooving, the axial dimension of the piston rod is extended by the amount of pushing of the entire circumferential protrusion of the rolling roller.

  In this case, since the piston rod is fixed in the axial direction by the positioning member and the pressing member, when the piston rod extends, the reaction force when the positioning member and the pressing member are pressed loads on the entire circumferential protrusion of the rolling roller. Acts as Since the life of the entire circumferential protrusion is shortened by the external load, there is a problem that the replacement frequency of the rolling roller is increased and the working efficiency is deteriorated.

  An object of the present invention is to provide a method for grooving a rod-shaped member that can extend the life of the roller by reducing the load acting on the entire circumferential protrusion of the roller from the outside.

In order to solve the above-described problems, the configuration of the present invention is characterized in that a plurality of rollers having a circumferential protrusion on the outer peripheral side and approaching and separating so as to sandwich the rod-shaped member from the radial direction, and the rod-shaped member A positioning member that positions the rod-shaped member in the axial direction by contacting one end of the rod-shaped member, and the rod-shaped member disposed on the opposite side of the positioning member with respect to the positioning member. A rod-shaped member positioning step, wherein the rod-shaped member is positioned in the axial direction by the positioning member and the pressing member, and the circumferential projection is rotated while driving the rollers. a groove processing step of processing the entire circumference grooves pressed against the outer peripheral surface of the machining relative to the projections of the roller in the middle of the groove processing step, to the groove depth the rod-shaped member is not displaced in the axial direction Once advanced, the member pressing the said positioning member is spaced from the rod-shaped member, and a positioning release process of a free state both ends of the bar-like member.

  According to the present invention, it is possible to reduce the load acting on the entire circumferential protrusion of the roller, thereby extending the life of the roller.

It is a longitudinal section showing a hydraulic shock absorber provided with a piston rod to which a grooving method according to an embodiment of the present invention is applied. It is a top view which shows the groove processing apparatus used for embodiment of this invention. It is an external appearance perspective view of the groove processing apparatus shown in FIG. It is the external appearance perspective view of the groove processing apparatus which looked at the state which has arrange | positioned the piston rod between each roller unit, and moved the positioning member to the positioning position from the same position as FIG. It is the external appearance perspective view of the groove processing apparatus which looked at the state which pressed the piston rod against the positioning member with the pressing member from the same position as FIG. FIG. 3 is an external perspective view of the groove processing device as seen from the same position as in FIG. 2 in a state where each roller unit is driven to rotate and the movable roller unit moves toward the piston rod. It is the top view of the principal part expansion which looked at each roller unit and piston rod in FIG. 6 from the upper side. It is the external appearance perspective view of the groove processing apparatus which looked at the state which made the circumferential protrusion of each rolling roller contact | abut to a piston rod, and rotated the piston rod from the same position as FIG. It is the expanded sectional view which looked at each rolling roller and piston rod from the arrow IX-IX direction in FIG. It is sectional drawing of the principal part expansion which looked at each rolling roller and piston rod from the arrow XX direction in FIG. It is sectional drawing of the principal part expansion seen from the same position as FIG. 10 which shows the state which pushed all the circumferential protrusions of each rolling roller into the outer peripheral surface of the piston rod to about 50% of the prescribed dimension. It is the external appearance perspective view of the groove processing apparatus which looked at the state which separated the pressing member from the piston rod from the same position as FIG. It is the external appearance perspective view of the groove processing apparatus which looked at the state which spaced apart the positioning member from the piston rod from the same position as FIG. It is sectional drawing of the principal part expansion seen from the same position as FIG. 10 which shows the state which pushed the perimeter protrusion of each rolling roller to the outer peripheral surface of the piston rod to the specified dimension. It is the top view of the principal part expansion which looked at the state which separated the movable roller unit from the piston rod from the same position as FIG. It is the top view of the principal part expansion which looked at the state which separated the movable roller unit from the piston rod from the same position as FIG. It is a flowchart which shows the groove processing procedure by a groove processing apparatus.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of grooving a rod-like member according to an embodiment of the present invention, a grooving apparatus used in the grooving method, and a hydraulic shock absorber provided with a piston rod to which the grooving method is applied will be described in detail with reference to FIGS. Explained.

  A configuration of the hydraulic shock absorber 1 provided with the piston rod 5 as a rod-like member in which the circumferential groove is formed by the groove processing method according to the present embodiment will be described with reference to FIG.

  The cylinder 2 constituting the outer shape of the hydraulic shock absorber 1 has a double cylinder structure including an inner cylinder 2A and an outer cylinder 2B, and a lower portion thereof is closed by a bottom cap 2C. On the other hand, the upper part of the cylinder 2 is closed by a rod guide 3. A piston 4 is inserted into the inner cylinder 2A of the cylinder 2 so as to be movable in the axial direction. One end of the piston rod 5 in the axial direction is attached to the piston 4 in the cylinder 2, and the other end protrudes through the rod guide 3 so as to be able to expand and contract.

  Here, the piston rod 5 constitutes a rod-shaped member and is formed as an elongated cylindrical body. Further, a hardened surface layer 5B (see FIG. 16) is formed on the outer peripheral surface 5A of the piston rod 5 so that the surface is not damaged by the expansion and contraction operation. Further, an entire circumferential groove 6 is formed on the outer peripheral surface 5A of the piston rod 5 at an intermediate position in the axial direction, and the entire circumferential groove 6 is formed by a groove machining method using a groove machining device 11 described later. It is what is done. A stopper member 7 that contacts the rod guide 3 when the piston rod 5 is greatly extended and restricts further extension is attached to the entire circumferential groove 6 by a coupling means such as metal flow coupling.

  Next, the groove processing device 11 for forming the circumferential groove 6 in the piston rod 5 of the hydraulic shock absorber 1 will be described.

  2 and 3 show a groove machining device 11 for machining the circumferential groove 6 in the piston rod 5. The groove processing device 11 is formed on the piston rod 5 by a rolling process that presses a circumferential protrusion 14B of the rolling roller 14 and a circumferential protrusion 18B of the rolling roller 18 which will be described later on the outer peripheral surface 5A of the piston rod 5. The circumferential groove 6 is formed. The groove processing device 11 is roughly constituted by a fixed roller unit 12, a movable roller unit 16, a positioning member 21, and a pressing member 22 which will be described later.

  The fixed roller unit 12 of the grooving device 11 is fixedly provided at a lateral position of a rod support 20 to be described later. The fixed roller unit 12 includes a rolling roller 14 attached to the rotating shaft 13 and two correction rollers 15A and 15B attached to the rotating shaft 13 with the rolling roller 14 interposed therebetween. Here, the rolling roller 14 is formed as a short cylindrical body, and an enlarged diameter portion 14 </ b> A having an enlarged diameter by one step is formed on the outer circumferential side of the rolling roller 14.

  Further, on the outer peripheral side of the enlarged diameter portion 14A, an entire circumferential protrusion 14B is provided so as to protrude radially outward. As shown in FIG. 11, the entire circumferential protrusion 14 </ b> B projects with a projecting dimension H <b> 1, and its cross-sectional shape is formed corresponding to the entire circumferential groove 6. Then, the entire circumferential protrusion 14B can form the entire circumferential groove 6 having a specified depth dimension by, for example, pushing almost all of the protruding dimension H1 into the outer peripheral surface 5A of the piston rod 5. That is, the prescribed depth dimension of the circumferential groove 6 is the same depth dimension H1 as the projection dimension H1 of the circumferential protrusion 14B.

  On the other hand, as shown in FIG. 7, the two correction rollers 15 </ b> A and 15 </ b> B are formed as short cylindrical bodies having a radial dimension that is the same as or slightly larger than the diameter-enlarged portion 14 </ b> A of the rolling roller 14. Each of the correction rollers 15A and 15B corrects the bending deformation of the piston rod 5 during the rolling process and finishes the piston rod 5 straight.

  A movable roller unit 16 is provided on the opposite side of the fixed roller unit 12 across the rod support 20 so as to be arranged in parallel with the fixed roller unit 12. This movable roller unit 16 is different from the fixed roller unit 12 in that the movable roller unit 16 can be translated in the horizontal direction in the direction of arrow A approaching the piston rod 5 and in the direction of arrow A ′ moving away from the piston rod 5. The other parts are similarly configured. That is, the movable roller unit 16 includes a rotating shaft 17, a rolling roller 18, and two correction rollers 19 </ b> A and 19 </ b> B. And an entire circumferential projection 18B.

  Here, since the fixed roller unit 12 and the movable roller unit 16 perform groove processing while rotating the piston rod 5 sandwiched between them, as shown in FIG. Can be rotationally driven. The piston rod 5 sandwiched between the fixed roller unit 12 and the movable roller unit 16 is rotationally driven in the direction of arrow C, which is reversely rotated.

  A rod support 20 is provided between the fixed roller unit 12 and the movable roller unit 16. The rod support 20 places the piston rod 5 at a predetermined height position, for example, at substantially the same position as the height position of the central axes of the roller units 12 and 16 as shown in FIG.

  As shown in FIGS. 2 and 3, a positioning member 21 is provided on one side of the rod support base 20 in the length direction. The positioning member 21 is movable in an arrow D direction approaching the piston rod 5 in the length direction of the rod support 20 and an arrow D ′ direction away from the piston rod 5. The positioning member 21 can position the piston rod 5 in the axial direction by bringing the tip of the abutting rod 21 </ b> A into contact with one end surface of the piston rod 5, and is axially positioned with respect to the outer peripheral surface 5 </ b> A of the piston rod 5. The circumferential groove 6 can be formed at an accurate position.

  Here, the positioning member 21 is disposed on an extension line in the length direction of the rod support base 20, and can move in the direction indicated by the arrow D or the direction indicated by the arrow D 'as described above. However, the positioning member 21 can be fixed so as not to move in the positioned state.

  A pressing member 22 is provided on the opposite side to the positioning member 21 in the axial direction across the rod support base 20. The pressing member 22 presses one end surface of the piston rod 5 against the tip of the contact rod 21 </ b> A of the positioning member 21 by pressing the piston rod 5 toward the positioning member 21. Thus, in a state where the piston rod 5 is pressed against the contact rod 21A, the piston rod 5 can be accurately arranged at the axial positioning position by the positioning member 21.

  The pressing member 22 has an expansion / contraction rod 22A, and the expansion / contraction rod 22A may extend toward the piston rod 5 in the direction of arrow E, or may decrease in the direction of arrow E ′ away from the piston rod 5. it can.

  Next, a groove machining method for forming the circumferential groove 6 in the piston rod 5 of the hydraulic shock absorber 1 using the groove machining device 11 will be described with reference to FIGS. 4 to 16 based on the flowchart of FIG. To do.

  First, when the piston rod 5 having the surface hardened layer 5 </ b> B is placed on the rod support 20, the positioning process of the piston rod 5 is started. In the piston rod 5 positioning step, the positioning is performed in the axial direction with the piston rod 5 sandwiched between the positioning member 21 and the pressing member 22. Specifically, in accordance with the flowchart of FIG. 17, in step 1, as shown in FIG. 4, the positioning member 21 is moved in the direction indicated by the arrow D, and the contact rod 21A is disposed at the position where the piston rod 5 is positioned. The positioning member 21 is fixed at the position.

  Next, when the positioning member 21 is fixed at the positioning position, the process proceeds to Step 2, and as shown in FIG. 5, the telescopic rod 22A of the pressing member 22 is extended in the direction of arrow E to press the piston rod 5, and the piston rod 5 is pressed against the contact rod 21 </ b> A of the positioning member 21. As a result, the positioning member 21 and the pressing member 22 can position the piston rod 5 in the axial direction by sandwiching the piston rod 5 in the axial direction. The entire circumferential groove 6 can be processed.

  When the piston rod 5 is positioned in the axial direction, the process proceeds to a groove machining step for machining the circumferential groove 6 in the piston rod 5. In this grooving process, as step 3, as shown in FIGS. 6 and 7, the fixed roller unit 12 having the rolling roller 14 and the movable roller unit 16 having the rolling roller 18 are rotationally driven in the direction indicated by the arrow B. In this state, the movable roller unit 16 is moved in the direction of arrow A toward the piston rod 5. Subsequently, in step 4, as shown in FIGS. 8 to 10, the circumferential protrusion 14 </ b> B of the rolling roller 14 and the circumferential protrusion 18 </ b> B of the rolling roller 18 are brought into contact with the outer circumferential surface 5 </ b> A of the piston rod 5. The circumferential groove 6 is formed by pressing the circumferential protrusions 14B and 18B against the outer circumferential surface 5A of the piston rod 5 while rotating the piston rod 5 in the direction indicated by the arrow C.

  Next, a positioning release step is performed in which the both ends of the piston rod 5 are in a free state in parallel with the progress of the groove forming step of forming the circumferential groove 6 on the outer peripheral surface 5A of the piston rod 5. In this positioning release step, in order to make the piston rod 5 free in the axial direction, the piston rod 5 is not displaced in the axial direction due to the engagement between the circumferential groove 6 being processed and the circumferential projections 14B and 18B. It is necessary to become.

  Accordingly, in step 5, as shown in FIG. 11, the projecting dimension H1 of the circumferential protrusions 14B and 18B of each rolling roller 14 and 18, that is, the prescribed depth dimension of the circumferential groove 6 is defined as the dimension H1. The depth dimension of the circumferential groove 6 on the way is defined as dimension H2. Based on this, in the present embodiment, when the groove depth dimension H2 in the course of machining of the circumferential groove 6 reaches about 50% of the projecting dimension H1 of the circumferential protrusions 14B and 18B, the piston is engaged by the concavo-convex engagement therebetween. The rod 5 is not displaced in the axial direction.

  It should be noted that the ratio at which the piston rod 5 is not displaced due to the relationship between the groove depth dimension H2 and the protrusion dimension H1 is the material of each rolling roller 14, 18 and piston rod 5, the shape of the circumferential protrusions 14B, 18B, It depends on conditions such as the prescribed depth dimension H1 of the circumferential groove 6 and the specifications of the groove processing apparatus 11, and is not limited to the above-mentioned ratio of about 50%.

  When the machining progresses to a groove depth at which the piston rod 5 is not displaced in the axial direction with respect to the circumferential protrusion 14B of the rolling roller 14 and the circumferential protrusion 18B of the rolling roller 18, as shown in FIG. The telescopic rod 22 </ b> A is retracted in the direction indicated by the arrow E ′ and separated from the piston rod 5.

  When the telescopic rod 22A of the pressing member 22 is separated from the piston rod 5, the process proceeds to step 6 where the positioning member 21 is retracted in the direction indicated by the arrow D 'as shown in FIG. Separate.

  Thereby, since both ends of the piston rod 5 are in a free state (free end), when the entire circumference projections 14B and 18B are pushed into the outer circumferential surface 5A of the piston rod 5 and the piston rod 5 extends in the axial direction, The piston rod 5 can be freely extended.

  In the grooving step, the process proceeds to step 7, and as shown in FIG. 14, the circumferential protrusion 14B of the rolling roller 14 and the circumferential protrusion 18B of the rolling roller 18 are formed on the outer peripheral surface of the piston rod 5 with a specified depth dimension H1. The entire circumferential groove 6 having a prescribed depth dimension H1 can be formed by pushing it down. Further, in step 8, as shown in FIGS. 15 and 16, the rotation of the roller units 12 and 16 is stopped, and the movable roller unit 16 is moved in the direction indicated by the arrow A 'so as to be retracted from the piston rod 5. Then, the groove machining for forming the entire circumferential groove 6 in the piston rod 5 is finished.

  Thus, according to the present embodiment, in the groove machining method for machining the entire circumferential groove 6 on the outer peripheral surface 5A of the piston rod 5, the piston rod 5 is sandwiched between the positioning member 21 and the pressing member 22 and positioned in the axial direction. A positioning process of the piston rod 5 is performed, and a groove machining process is performed in which the circumferential grooves 6 are machined by pressing the circumferential protrusions 14B and 18B against the outer circumferential surface 5A of the piston rod 5 while rotationally driving the rolling rollers 14 and 18. .

  In the middle of the grooving step, a positioning release step is performed in parallel with the grooving step, in which the positioning member 21 and the pressing member 22 are separated from the piston rod 5 and both ends of the piston rod 5 are in a free state. Do.

  Therefore, when the circumferential protrusion 14B of the rolling roller 14 and the circumferential protrusion 18B of the rolling roller 18 are pushed into the outer peripheral surface 5A of the piston rod 5 and the piston rod 5 extends in the axial direction, the positioning member 21 and the pressing member The piston rod 5 can be freely extended without striking 22.

  As a result, the reaction force caused by the expanded piston rod 5 pressing the positioning member 21 and the pressing member 22 does not act as a load on the circumferential protrusion 14B of the rolling roller 14 and the circumferential protrusion 18B of the rolling roller 18. In addition, the lifetime of the entire peripheral projections 14B and 18B can be extended. Thereby, the exchange frequency of each rolling roller 14 and 18 can be reduced, and improvement of work efficiency, reduction of manufacturing cost, etc. can be aimed at.

  In addition, in embodiment, the piston rod 5 of the hydraulic shock absorber 1 was applied as a rod-shaped member, and it demonstrated and demonstrated the groove processing method which forms the perimeter groove | channel 6 in the piston rod 5 using the groove processing apparatus 11 as an example. . However, the present invention is not limited to this, and the groove processing method of the present invention may be applied to the case where the circumferential groove 6 is formed on a rod-shaped member other than the piston rod 5. Moreover, it can also apply to a hollow pipe-shaped rod-shaped member as a rod-shaped member.

  Next, the invention included in the above embodiment will be described. The rod-shaped member is a piston rod used for a shock absorber that relieves vibration. Thereby, a circumferential groove can be machined with respect to the piston rod of the shock absorber.

1 Hydraulic shock absorber 5 Piston rod (bar-shaped member)
5A Outer peripheral surface 6 Fully circumferential groove 11 Groove processing device 14, 18 Rolling roller 14B, 18B Fully circumferential projection 21 Positioning member 22 Pressing member H1 Projection dimension of circumferential projection (groove depth dimension of circumferential groove)
Groove depth dimension during machining of H2 all-around groove

Claims (2)

The rod-shaped member is positioned in the axial direction by abutting a plurality of rollers that have a circumferential protrusion on the outer circumferential side and approach and separate the rod-shaped member so as to sandwich the rod-shaped member from the radial direction and one end of the rod-shaped member in the axial direction. A positioning member that is disposed on the opposite side of the positioning member with respect to the positioning member, and pressing the rod-shaped member against the positioning member.
A rod-shaped member positioning step for positioning in the axial direction with the rod-shaped member sandwiched between the positioning member and the pressing member;
A groove machining step of machining the circumferential grooves by pressing the circumferential protrusions against the outer peripheral surface of the rod-shaped member while rotating the rollers;
When the processing progresses to a groove depth at which the rod-shaped member is not displaced in the axial direction with respect to the protrusion of the roller during the groove processing step, the positioning member and the pressing member are separated from the rod-shaped member, A method for grooving a rod-shaped member, comprising a positioning release step for freeing both ends of the rod-shaped member.   The groove processing method for a rod-shaped member according to claim 1, wherein the rod-shaped member is a piston rod used for a shock absorber that reduces vibration.

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