JPH0841531A - Method for hardening guide bearing parts - Google Patents

Abstract

PURPOSE:To provide a method for forming and hardening stock capable of easily forming by cold drawing even in complicated shape parts, furthermore capable of selectively increasing the surface hardness in a specified place and capable of suppressing its deformation caused by hardening to a minimum. CONSTITUTION:Low carbon steel stock is subjected to forming by a cold drawing into a prescribed sectional shape. Thereafter, the whole surface of the formed part is carburized to increase the carbon concn. in the surface, and next, only the required prescribed part in the hardness is subjected to local hardening by induction hardening or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rolling machine elements such as various types of rolling bearings and linear guide bearings (linear guide devices), and in particular, parts used like linear guide devices have a complicated irregular cross-sectional shape. The present invention relates to a quenching method in which a quench-hardened portion can be easily obtained even when it has a long thin wall.

[0002]

2. Description of the Related Art The above-mentioned rolling machine elements are often required to withstand repeated shear stress under high surface pressure to move and secure a rolling fatigue life. Hardness is increased. Particularly in the linear guide device, as a conventional quenching method, a method of performing carburizing quenching using low carbon steel and a method of performing induction quenching using high carbon steel are well known.

In the former case, when manufacturing components such as guide rails and sliders, low carbon steel is used as a raw material for cold drawing to form a general shape with a predetermined cross section and then carburizing and quenching. Since the carbon concentration of the material is low, there is an advantage that it can be easily formed by cold drawing. The latter is cold drawing using high carbon steel as a raw material, and if it has a complicated shape, it is formed into a predetermined shape through a process of auxiliary machining, and then the forming material is surrounded by a coil for induction hardening and partially hardened. Since induction hardening is performed, there is an advantage that it is easy to partially quench an arbitrary part.

[0004]

A portion to which repeated shear stress is applied, such as a rolling rail rolling groove in a guide rail or a slider of a linear guide device, has a high surface hardness in order to secure a rolling fatigue life. Need that. However, in the case of the above-mentioned carburizing and quenching method, when partially hardening and hardening such a specific part, a step of applying a copper plating or applying a carburizing preventive agent to other parts is required to prevent hardening and hardening. However, there is a problem in that the process becomes complicated accordingly.

Further, the surface of the low carbon steel is impregnated with carbon to increase the carbon concentration on the surface and then quenching is performed. In the quenching step, the entire part is heated to a high temperature and then rapidly cooled. Therefore, the more irregular the shape of the part, the more unbalanced the cooling rate of the whole part, resulting in large deformation and bending,
There is a problem that twisting may occur, and a step of correcting deformation, bending, and twisting after quenching is required.

On the other hand, in the case of the above induction hardening method, partial hardening treatment can be easily dealt with by designing the hardening coil, and since it is not necessary to apply heat to the entire part, it is possible There is little deformation, bending, and twisting, and it is easy to correct such deformation.
On the other hand, if it has a complicated shape, since it is made of high carbon steel, it is extremely difficult to form it by cold drawing. That is, there is a problem in that it is not possible to form into a general shape only by cold drawing and auxiliary machining is required.

Further, the surface portion may be decarburized during cold drawing of high carbon steel, in which case there is a problem that a carburizing step is required and the cost becomes high. Therefore,
The present invention has been made by paying attention to the above-mentioned conventional problems, and it is possible to easily form a complicated shaped part such as a guide rail or a slider of a linear guide device by cold drawing, and to roll the rolling elements. (EN) A method of quenching a complex-shaped part that can easily increase the surface hardness of a specific part such as a moving groove and can suppress the deformation due to quenching to a minimum. Has an aim.

[0008]

A method of quenching a guide bearing component according to the present invention is to carburize the entire surface of a low carbon steel material cold-drawn into a predetermined sectional shape to increase the carbon concentration on the surface, The present invention is characterized in that only a predetermined portion of the carburized surface that requires hardness is subjected to partial quenching.

[0009]

[Function] Since low carbon steel is used as the material, the forming process by cold drawing can be easily performed. Further, since the material surface is carburized and the partial hardening such as the induction hardening is selectively used for the hardening of the specific portion requiring the surface hardness, the deformation at the hardening is suppressed to the minimum. In addition, it is easy to correct bending after partial hardening.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a first embodiment of the present invention, and is a front view showing, in the order of steps, the states of forming and hardening of a guide rail 1 of a linear guide device. Guide rail 1 of this embodiment
As shown in FIG. 1 (a), it is a relatively thin, substantially U-shaped cross-sectional shape that is long in the axial direction and has a rolling element rolling groove 2 on the inner surface of the recess. .

The material of the guide rail 1 is, for example, low carbon steel SCM415H (C content 0.12 to 0.18%) or SCM.
A low carbon steel having a C content of about 0.2% such as 420H (C content of 0.17 to 0.23%) is used. FIG. 2 shows the steps of forming and quenching the material for the guide rail 1 of this embodiment. Explaining step by step, step 1 is a step of cold drawing into a general shape using the low carbon steel. Since the material is low carbon steel, cold drawing can be easily performed even for such a deformed part. In addition, in order to further improve the cold formability, spheroidizing annealing treatment may be performed.

Step 2 is a step of carburizing the entire surface of the guide rail 1 formed by cold drawing. This carburizing treatment is performed for the purpose of diffusing and permeating carbon into the surface of the steel material by a chemical reaction. Carburizing method is solid carburizing,
Either liquid carburizing or gas carburizing may be used. In this example, the gas carburizing was adopted. Further, the formation state of the carburized layer 10 is schematically shown in FIG.

Quenching after carburizing is performed at a temperature lower than the carburizing temperature, and thereafter, cooling is performed in air to prevent quench hardening. Step 3 is a step of subjecting a portion requiring high surface hardness, that is, the groove surface of the rolling element rolling groove 2 of the guide rail 1 to induction hardening. In this step, a high-frequency current is passed by using an induction hardening coil that is placed close to the rolling element rolling groove 2 of the guide rail 1, and only the surface portion of the steel rolling element rolling groove 2 is heated by an induced current and then cooled. Water was sprayed on to quench and cure. This quench hardening is performed by continuously moving the guide rail with respect to the coil. In this case, the curing depth can be adjusted by the AC frequency, the current value, and the moving speed of the coil.
And quenching with KHz, hardness in cure depth 1mm is H _R C
62 was obtained.

Step 4 is a step of tempering the guide rail 1 which has been subjected to the above quenching treatment. As a result, as shown in FIG. 1C, the high hardness induction hardened portion 11 was formed only in the rolling element rolling groove 2 on the inner surface of the guide rail 1. Step 5 is a step of correcting the bending, twisting and the like of the guide rail 1 caused by the above heat treatment.
The degree of bending of the guide rail 1 after the above heat treatment was extremely small, and the bending was easily corrected.

FIG. 3 is a second embodiment of the present invention, and is a front view showing, in the order of steps, the state of molding and quenching of the slider body 5 of the linear guide device assembled to the guide rail 1 of FIG. The slider body 5 of this embodiment is shown in FIG.
As shown in (a), it is a deformed part that is relatively thick and has an axial recessed groove 6 in the upper part and a relatively short length. The rolling element rolling groove 7 is provided to face the rolling element rolling groove 2. Further, the thick portion has axial through holes 8, 8 parallel to the rolling element rolling groove 7, and an end cap (not shown) mounted on the slider body 5 at a position immediately above each through hole 8 by screwing. Mounting screw holes 9, 9 are provided.

The material of the slider body 5 is the same as that of the guide rail 1. Further, the forming method and the quenching method of the material are the same as in the case of the guide rail 1 shown in FIG. FIG. 4 shows a third embodiment, which is an example in which the present invention is applied to a guide rail 1A of a linear guide device of a type in which a slider is mounted across a guide rail having a substantially prismatic shape.

This guide rail 1A is provided with rolling member rolling grooves 2A having a substantially semi-circular shape on both side surfaces thereof, and has a substantially quarter circular rolling shape on the ridge lines between both side surfaces and the upper surface. The moving body rolling groove 2B is provided. The material of this guide rail 1A is
It is the same as the above guide rail 1. Further, the forming method and the quenching method of the material may be substantially the same as the case of the guide rail 1 shown in FIG. However, in this case, in the partial induction hardening step, the rolling element rolling groove 2 of the guide rail 1A is
Induction hardening portions 11 are formed on both side surfaces of the upper half of the rail including both A and 2B.

FIG. 5 shows a fourth embodiment, in which the present invention is applied to a slider body 5A having a substantially U-shaped cross section which is assembled to the guide rail 1A of the third embodiment. The slider body 5A has substantially semicircular rolling element rolling grooves 7A on both inner surfaces thereof, which face the rolling element rolling grooves 2A and 2B of the guide rail 1A of the third embodiment. 7B
It has.

The material used for this slider body 5A is
This is the same as the case of the slider body 5. Further, the forming method and the quenching method of the material may be substantially the same as the case of the guide rail 1 shown in FIG. However, in this case, in the partial induction hardening step, the induction hardening portion 11 is formed on both inner side surfaces of the slider body including both the rolling element rolling grooves 7A and 7B of the slider body 5.

FIG. 6 shows a modification of the second embodiment. This is a slider body of a linear guide device of the type in which a slider is driven by a ball screw, and has a threaded hole 12 at its center for penetrating a ball screw shaft through a ball. The threaded hole 12 is formed by cold-drawing a low carbon steel material, then forming a through hole with a drill, and machining a rolling element rolling groove on the inner peripheral surface of the through hole by turning.

The rolling element rolling groove formed in the screw hole 12 also needs to be quenched and hardened in the same manner as the rolling element rolling groove 7 of the second embodiment. This quenching and hardening method for rolling grooves of rolling elements may also be carried out as in the second method. However, induction hardening of the rolling element rolling groove of the screw hole is performed by inserting a heat treatment coil bent like a hairpin into the screw hole 12.
With such a quenching method, the step of applying a carburizing agent to the portion other than the screw hole processed portion as in the case of carburizing and quenching is unnecessary, and heat treatment of a thin portion caused by forming a screw hole in the center of the slider The deformation due to can be minimized.

In each of the above embodiments, the guide rails and sliders of the linear guide device have been described as an example of complicated shaped parts, but the invention is not limited to this and can be applied to other parts. is there. Further, in each of the above examples, the high frequency heat treatment was applied to a predetermined portion requiring hardness, but other partial quenching methods, if necessary,
For example, a quenching method using a laser beam or the like may be used.

Furthermore, in each of the above-mentioned embodiments, the linear guide device in which the slider is linearly guided by the linear guide rail has been described, but the slider is curved by the linear guide rail. It may be a guide bearing device that is guided physically.

[0024]

As described above, in the quenching method for guiding bearing parts according to the present invention, the carbon of the surface is obtained by carburizing the entire surface of the low carbon steel material cold-drawn into a predetermined cross-sectional shape. Since the concentration is increased and then only the specified portion of the carburized surface that requires hardness is subjected to partial quenching, even parts with complicated shapes can be easily formed into a full shape by cold drawing. There is no need to perform machining or carburization or recarburization in the process, the process is completed in a short carburizing time, the process is simplified and the cost can be reduced, and the part that requires high hardness In addition, it is easy to selectively increase the surface hardness by partial quenching such as induction hardening, and moreover, quenching deformation can be suppressed to a minimum, and shape correction after quenching is also easy. Achieve the.

[Brief description of drawings]

FIG. 1 is a front view illustrating an aspect of a forming process and a quenching process according to a first embodiment of the present invention.

FIG. 2 is a flow chart for explaining the steps of material forming and quenching according to the present invention.

FIG. 3 is a front view illustrating an aspect of forming processing and quenching processing according to a second embodiment of the present invention.

FIG. 4 is a front view illustrating an aspect of forming processing and quenching processing according to a third embodiment of the present invention.

FIG. 5 is a front view illustrating a mode of forming and quenching processing according to a fourth embodiment of the present invention.

FIG. 6 is a front view for explaining a mode of forming and quenching in a modification of the second embodiment of the present invention.

[Explanation of symbols]

 1 Guide rail 1A Guide rail 2 Rolling element rolling groove (part requiring hardness) 2A Rolling element rolling groove (part requiring hardness) 2B Rolling element rolling groove (part requiring hardness) 5 Slider body 5A Slider Main body 7 Rolling element rolling groove (part requiring hardness) 7A Rolling element rolling groove (part requiring hardness) 7B Rolling element rolling groove (part requiring hardness) 10 Carburized layer 11 Hardened layer

Claims (1)

[Claims] 1. A carburizing method is applied to the entire surface of a low carbon steel material cold-drawn into a predetermined cross-sectional shape to increase the carbon concentration on the surface,
Then, a method for quenching a guide bearing component, characterized in that only a predetermined portion of the carburized surface requiring hardness is subjected to partial quenching.