JP2005103572A - Method for grooving rod, and form rolling roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the performance of a form rolling roller from being degraded due to the cracks caused on the form rolling roller or the like by eliminating large stress concentrating parts from the form rolling roller for grooving. <P>SOLUTION: In a method for working a groove 2 by forming projecting part 20 provided on the form rolling rollers 11A, 11B on the peripheral surface of a surface-hardened rod 1, by this method, the form rolling rollers 11A, 11B are bisected in the axial direction on the boundary S between the steep inclined parts 20a of the forming projecting part 20 and the working reference plane 22 which is continued to the steep inclined part 20a, the main roller 23 and the assistant roller 24 of divided elements are integrated with bolts 26 and the stress which is liable to concentrate on the boundary S at rolling is distributed onto the main roller 23 and the assistant roller 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rod groove processing method for rolling a groove on the surface of a rod such as a hydraulic shock absorber and a cylinder device, particularly a rod subjected to surface hardening treatment, and a rolling roller used for carrying out the method.

  For example, a stopper member for restricting the extended end is fixed to a rod (piston rod) in a hydraulic shock absorber, and conventionally, welding is generally used for fixing the stopper member. However, according to the method in which the stopper member is joined to the rod by welding, spatter generated during welding adheres to the rod and enters the oil chamber as foreign matter (contamination) when assembling the hydraulic shock absorber later, which reduces performance. There was a risk of causing it.

  Therefore, recently, a groove (annular groove) is formed in the middle of the rod, and a collar is fitted into the groove using, for example, metal flow bonding, and this collar is used as the stopper member and welding is omitted. Is being considered. However, the rod is usually subjected to induction hardening and tempering treatment (surface hardening treatment), and the surface thereof has a Vickers hardness (Hv) of 400 or higher. For this reason, in order to form the groove, it is necessary to rely on cutting (turning), and in this case, the hardened surface hardened layer is deleted.

  As a result of intensive studies on the formation of the above-mentioned grooves, the present inventors have found that even a rod subjected to a surface hardening treatment can be grooved using rolling, and has already been disclosed in Patent Document 1. Revealed. As shown in FIG. 4, this method is performed by gradually reducing the distance between the pair of rolling rollers 5 while rolling the rod 1 to be processed between the pair of rolling rollers 5 (one side is omitted) ( A) → (B) → (C) is used to bite the forming convex portion 6 provided on the outer peripheral surface of each rolling roller 5 into the peripheral surface of the rod 1, and finally to the peripheral surface of the rod 1. The groove 2 in which the cross-sectional shape of the molding convex portion 6 is transferred is created. As described above, according to the groove processing using rolling, the molding convex portion 6 of the rolling roller 5 is pushed into the groove 2 while maintaining the thickness of the surface hardened layer substantially. The effect of increasing strength will not be lost.

  The forming convex portion 6 of the rolling roller 5 is set on the upper surface 8 of the annular convex seat 7, and this upper surface 8 is a processing reference surface that defines the rolling depth. Further, since the groove 2 processed into the rod 1 is used for joining a stopper member (collar) in the hydraulic shock absorber, the groove 2 has a different shape that is steeper than the other side. Thus, the forming convex portion 6 of the rolling roller 5 also has a steeply inclined portion 6b whose one side is steeply inclined with respect to the processing reference surface 8 and a gently inclined portion 6b whose other side is gently inclined with respect to the processing reference surface 8. As each is configured.

JP 2003-254436 A

  By the way, in the groove processing by rolling described above, as shown in FIG. 4 (B), the material bulge 3 occurs on both sides of the indentation region of the molding convex portion 6 with respect to the rod 1 at the initial stage of the processing. A phenomenon occurs in which the ascending 3 is crushed by the machining reference surface 8 of the rolling roller 5 from the middle stage to the last stage of machining. As a result of the crushing 3 being crushed by the processing reference surface 8, a large stress is generated in the rolling roller 5 as a reaction force, and this stress is particularly generated by the steeply inclined portion 6a of the forming convex portion 6 and the processing reference. Concentration on the boundary (corner portion) S with the surface 8 may cause cracks in the rolling roller 5, and in this case, the performance of the rolling roller 5 is degraded, so the rolling roller 5 needs to be replaced. Occurs.

  The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to prevent deterioration of the performance of the rolling roller by eliminating a large stress concentration portion from the rolling roller, and thus the rod. It is an object of the present invention to provide a rod groove processing method capable of stably performing the groove processing for a long period of time, and to provide a suitable rolling roller for the implementation of the method.

  In order to solve the above-described problems, the rod groove processing method according to the present invention includes a rolling roller pressed against a rod formed by surface hardening treatment at a boundary between an annular forming convex portion and processing reference surfaces on both sides thereof. Then, it is divided in the axial direction at least at the boundary where stress is concentrated more at the time of rolling, and the stress generated at the time of rolling is distributed to the dividing elements. In this rod groove processing method, the rolling roller annular forming convex portion has a steep slope whose one side is steeply inclined with respect to the reference outer peripheral surface, and a gentle slope whose other side is gently inclined with respect to the reference processing surface. The rolling roller may be divided into two in the axial direction at the boundary between the steeply inclined portion of the forming convex portion and the processing reference surface following the steeply inclined portion. In the rod groove processing method performed in this way, the stress generated in the rolling roller is distributed to the dividing elements, so that it is possible to prevent the rolling roller from degrading in performance due to cracks in the rolling roller.

  The rolling roller according to the present invention is a rolling roller used in the above-described rod groove processing method, and is a boundary between the annular forming convex portion and the processing reference surfaces on both sides thereof, and at least more stress is generated during rolling. It is characterized by being divided in the axial direction at the boundary on the concentrated side. In this rolling roller, one side of the annular forming convex portion is configured as a steeply inclined portion that is steeply inclined with respect to the processing reference surface, and the other side is configured as a gently inclined portion that is gently inclined with respect to the processing reference surface. And it can be set as the structure divided into two in the axial direction at the boundary between the steeply inclined portion of the forming convex portion and the processing reference surface following the steeply inclined portion.

  According to the rod groove processing method and the rolling roller according to the present invention, since the rolling roller is divided and a large stress concentration portion is eliminated from the rolling roller, the rolling roller is cracked, etc. As a result, it is possible to prevent the performance from deteriorating and the service life thereof is greatly extended, which has the effect of greatly contributing to the reduction of the production cost and the improvement of the productivity.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
In this embodiment, a groove 2 for joining a stopper member (collar) to a rod (piston rod) 1 used in the hydraulic shock absorber described above by metal flow molding is to be rolled. Has been subjected to surface hardening treatment such as induction hardening tempering or carburizing quenching tempering in advance.

  FIG. 3 shows the overall structure of a rolling device for machining the groove 2 in the rod 1 described above. In the figure, 10A and 10B are two rotating shafts arranged in parallel, 11A and 11B are rolling rollers that are non-rotatably attached to the rotating shafts 10A and 10B, respectively, and two rolling rollers A support 12 for supporting the rod 1 is disposed between 11A and 11B. In the present embodiment, a pair of correction rollers 14A and 14B are attached to the two rotary shafts 10A and 10B in a non-rotatable manner via spacers 13A and 13B on both sides of the corresponding rolling rollers 11A and 11B. Yes.

  The two rotating shafts 10A and 10B are rotationally driven in the same direction by a driving means (not shown), and accordingly, the two rolling rollers 11A and 11B and the two pairs of correction rollers 14A. , 14B also rotate in the same direction. The two rotating shafts 10A and 10B are also configured such that one of them (here, 10A) approaches and separates from the other 10B, and accordingly, the two rolling rollers 11A and 11B and the two pairs As for the correction rollers 14A and 14B, the respective ones 11A and 14A approach and separate from the other 11B and 14B.

  On the peripheral surface of each rolling roller 11A, 11B, an annular forming convex portion 20 for rolling the groove 2 on the peripheral surface of the rod 1 is provided. As shown in FIGS. 1 and 2, the molding convex portion 20 is set on the upper surface 22 of the annular convex seat 21, and the upper surface 22 is a processing reference surface that defines the rolling depth. . As described in the background section above, the forming convex portion 20 has a cross-sectional shape that matches the irregular shape of the groove 2, and one side thereof has a steeply inclined portion that is steeply inclined with respect to the processing reference surface 22. 20a is configured as a gently inclined portion 20b whose other side is gently inclined with respect to the processing reference surface 22 (FIG. 2). On the other hand, each of the pair of straightening rollers 14A and 14B has a flat peripheral surface, and is the outer diameter thereof the same as the outer diameter (reference outer diameter) of the convex seat 21 of the rolling rollers 11A and 11B? The diameter is set slightly smaller than that.

  Here, each rolling roller 11A, 11B is divided into two in the axial direction at the boundary S between the steeply inclined portion 20a of the forming convex portion 20 and the processing reference surface 22 as well shown in FIGS. ing. More specifically, each of the rolling rollers 11A and 11B includes a main roller 23 having a forming convex portion 20 and a processing reference surface 22 following the gently inclined portion 20b of the forming convex portion 20, and a steeply inclined portion of the forming convex portion 20. It consists of a sub roller 24 having a processing reference surface 22 following 20b. The main roller 23 has a shape having a cylindrical boss portion 25 on the inner diameter side which is a fitting portion with respect to the rotary shafts 10A and 10B, while the sub roller 24 has a simple ring shape. The main roller 23 is provided with a plurality of screw holes 25 equally distributed in the circumferential direction thereof, and the sub-roller 24 is in a state of being lightly fitted to the boss portion 25 and the screw holes 25. It is fastened and fixed to one surface of the main roller 23 by a bolt 26 screwed into the main roller 23.

Hereinafter, the rod groove processing method by the rolling device configured as described above will be described.
When grooving, one rolling roller 11A is previously separated from the other rolling roller 11B, and the rod 1 is placed on the support base 12 in this state. Then, while rotating the two rolling rollers 11A and 11B in the same direction, the one rolling roller 11A is brought closer to the other rolling roller 11B. Then, the rod 1 on the support base 12 rolls between the rolling rollers 11A and 11B, and the annular forming convex portion 20 provided on the peripheral surface of each rolling roller 11A, 11B is the rod 1's. It is gradually pushed into the peripheral surface. Finally, the entire molding convex part 20 is pushed into the peripheral surface of the rod 1, and thereby the irregularly shaped groove 2 described above is created on the peripheral surface of the rod 1.

  During the above groove processing, as shown in FIG. 2, the bulges 3 of the material generated on both sides of the indentation region of the molding convex portion 20 with respect to the rod 1 at the initial stage of machining are processed on the convex seat 21 from the middle stage to the last stage of machining. It is crushed by the reference surface 22. As a result, a large stress is generated in the rolling rollers 11A and 11B, and this stress tends to concentrate on the boundary (corner portion) S between the steeply inclined portion 20a of the forming convex portion 20 and the subsequent processing reference surface 22. Since the rolling rollers 11A and 11B are divided in the axial direction at the boundary S where the stress tends to concentrate, the stress is distributed to the main roller 23 and the sub roller 24 which are the dividing elements. As a result, it is possible to prevent the rolling roller from degrading in performance due to, for example, cracking in the rolling rollers 11A and 11B.

Thus, according to the rod groove processing using rolling, the surface hardened layer is pushed into the groove 2 while maintaining its thickness substantially, so that the effect of increasing the strength by the surface hardening treatment is lost. Absent.
Further, during the above-described grooving, excess meat (material) generated by the pressing of the molding convex portion 20 flows in the axial direction, so that the entire rod 1 is bent around the groove 2. In the embodiment, since the correction rollers 14A and 14B are disposed on both sides of the respective rolling rollers 11A and 11B, the occurrence of the bending described above is suppressed, and the rod 1 having excellent straightness can be obtained.

In the above embodiment, each of the rolling rollers 11A and 11B is divided into two in the axial direction at the boundary S between the steeply inclined portion 20a of the forming convex portion 20 and the subsequent processing reference surface 22. Depending on the shape of the forming convex portion, both sides may be stress concentration portions. In this case, the rolling roller is moved in the axial direction at the connecting portion (boundary) on both sides of the forming convex portion with respect to the processing reference surface 22. It is desirable to divide into three parts.
Moreover, the kind of rod which this invention makes a process target is arbitrary, The application will not be ask | required if surface hardening processing is performed previously.

It is sectional drawing which shows the structure of the rolling roller used for implementation of the rod groove processing method which concerns on this invention, and the implementation condition of rolling. It is sectional drawing which expands and shows the principal part structure of this rolling roller. It is sectional drawing which shows the whole structure of the rolling apparatus used for implementation of this rod groove processing method, and the implementation condition of rolling. It is sectional drawing which shows the rod groove processing method by the conventional rolling over time.

Explanation of symbols

1 Rod (piston rod)
2 Groove 10A, 10B Rotating shaft 11A, 11B Rolling roller 20 Forming convex part 20a Steeply inclined part 20b Slowly inclined part 22 Processing reference surface 23 Main roller 24 Sub-roller S Boundary between steeply inclined part and processing reference surface

Claims (4)

A rod groove processing method for forming a groove on a peripheral surface of a rod subjected to surface hardening treatment by rolling, wherein a rolling roller pressed by the rod is formed with an annular forming convex portion and processing standards on both sides thereof. A rod groove machining method characterized by dividing in the axial direction at least at a boundary with a surface where stress is more concentrated at the time of rolling, and dispersing the stress generated at the time of rolling to the divided elements . The annular forming convex part of the rolling roller is configured as a steeply inclined part whose one side is steeply inclined with respect to the reference outer peripheral surface, and as a gently inclined part whose other side is gently inclined with respect to the processing reference surface. 2. The rod groove processing according to claim 1, wherein the rolling roller is divided into two in the axial direction at a boundary between a steeply inclined portion of the forming convex portion and a processing reference surface following the steeply inclined portion. Method. In a rolling roller having an annular molding convex part that rolls a groove on a peripheral surface of a rod subjected to surface hardening treatment, the boundary between the annular molding convex part and the processing reference surfaces on both sides thereof, A rolling roller characterized by being divided in the axial direction at least at a boundary where stress is concentrated more during rolling. The annular forming convex portion is configured as a steeply inclined portion whose one side is steeply inclined with respect to the processing reference surface, and the other side as a gently inclined portion where the other side is gently inclined with respect to the processing reference surface. The rolling roller according to claim 3, wherein the roller is divided into two in the axial direction at a boundary between a steeply inclined portion of the portion and a processing reference surface following the steeply inclined portion.

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