JP2008089028A - Linear guide device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear guide device equipped with a guide rail having an excellent fatigue strength. <P>SOLUTION: The linear guide device comprises the guide rail 1 having a rolling element rolling groove 10, a slider 2 attached to the guide rail 1 having a rolling element rolling groove 11 opposed to the rolling element rolling groove 10 of the guide rail 1, and moving relatively in the axial direction, and a plurality of rolling elements 3 freely turnably arranged between both the rolling element rolling grooves 10, 11. Induction heating is applied to the guide rail 1 on both sides 1a, 1a. A hardness layer 20 is formed in the whole surface of both the sides 1a, 1a including the groove surface of the rolling element rolling groove 10. The surface harness of the hardness surface 20 is not less than Hv674 (not greater than HRC59). The depth of the effective hardness layer is not less than 10 to 50% of the diameter of the rolling element 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a linear guide device.

Patent Document 1 describes a guide rail in which induction hardening is performed on the entire side surface. And the fatigue strength of a guide rail is improved by making the depth of the hardened layer formed by induction hardening substantially uniform.
JP-A-8-86313

However, Patent Document 1 does not sufficiently examine the hardness of the hardened layer and the depth of the hardened hardened layer. In induction hardening, the hardness of the hardened layer and the depth of the hardened hardened layer change relatively easily. Therefore, the formed hardened layer may not have a practically sufficient hardened hardened layer depth. Moreover, there is a possibility that an overheating state is partially generated during induction hardening, and the strength of the region is lowered.
Then, this invention makes it a subject to solve the problem which the above prior arts have, and to provide the linear guide apparatus provided with the guide rail which has the outstanding fatigue strength.

  In order to solve the above-described problems, the present invention has the following configuration. That is, the linear guide device according to the present invention includes a guide rail having a rolling element rolling groove extending in the axial direction on the outer surface, a rolling element rolling groove facing the rolling element rolling groove of the guide rail, and the shaft. In the linear guide device comprising: a slider attached to the guide rail so as to be relatively movable in a direction; and a plurality of rolling elements that are arranged to freely roll between the rolling element rolling grooves. A hardened layer having a surface hardness of Hv674 or higher by induction hardening is formed on the groove surface of the moving groove, and the effective hardened layer depth is 10% or more and 50% or less of the diameter of the rolling element.

  Since the linear guide device of the present invention includes a guide rail having excellent fatigue strength, it is excellent in durability.

An embodiment of a linear guide device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a linear guide device according to the present invention, and FIG. 2 is a front view of the linear guide device of FIG. 1 viewed from the axial direction (however, the end cap is omitted). Is shown).
First, the configuration of the linear guide device of the present embodiment will be described. On a guide rail 1 having a substantially square cross section extending in the axial direction, a slider 2 having a substantially U-shaped cross section is assembled so as to be relatively movable in the axial direction.

Rolling element rolling grooves 10 and 10 each formed of a concave groove having a substantially arc-shaped cross section extending in the axial direction are formed at the ridge line portion where the upper surface of the guide rail 1 and both side surfaces 1a and 1a intersect. Rolling element rolling grooves 10 and 10 each having a substantially semicircular cross section extending in the axial direction are formed at intermediate positions on both side surfaces 1a and 1a of the guide rail 1.
The slider 2 includes a slider body 2A and end caps 2B and 2B that are detachably attached to both end portions in the axial direction. Further, both end portions of the slider 2 (end surfaces of the end caps 2B). ) Are provided with side seals 5 and 5 for sealing the opening of the gap between the guide rail 1 and the slider 2.

Furthermore, rolling element rolling grooves 11, 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10, 10 of the guide rail 1 are formed at the corners of the inner surfaces of both sleeve portions 6, 6 of the slider body 2 </ b> A. Formed at the center of the inner surface of the sleeves 6 and 6 are rolling element rolling grooves 11 and 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10 and 10 of the guide rail 1. Yes.
The rolling element rolling grooves 10, 10, 10, 10 of the guide rail 1 and the rolling element rolling grooves 11, 11, 11, 11 of both sleeve portions 6, 6 have a substantially circular cross section. 14, 14, 14, and 14 are formed, and these rolling element rolling paths 14 extend in the axial direction. The number of rolling element rolling grooves 10 and 11 provided in the guide rail 1 and the slider 2 is not limited to two rows on one side, and may be one row on one side or three rows or more, for example.

Furthermore, the slider 2 is formed of a through-hole having a circular cross-section that penetrates in the axial direction in parallel to the rolling element rolling path 14 at the upper and lower portions of the thick portions of the sleeve portions 6 and 6 of the slider body 2A. A moving body return path 13, 13, 13, 13 is provided.
On the other hand, although not shown, the end caps 2B and 2B having a substantially U-shaped cross section have a rolling element rolling path 14 and a rolling element return path parallel to the rolling element rolling path 14 on the contact surface (back surface) with the slider body 2A. The rolling element rolling path 14, the rolling element return path 13, and the curved paths at both ends form a substantially annular rolling element circulation path. . In this rolling element circulation path, a large number of rolling elements (balls) 3 made of, for example, steel balls are loaded so as to freely roll.

  When the slider 2 assembled to the guide rail 1 is moved in the axial direction along the guide rail 1, the rolling element 3 loaded in the rolling element rolling path 14 rolls in the rolling element rolling path 14. It moves in the same direction as the slider 2 with respect to the guide rail 1 while moving. When the rolling element 3 reaches one end of the rolling element rolling path 14, it is scooped up from the rolling element rolling path 14 by the tongue provided in the end cap 2B and sent to the curved path.

The rolling element 3 having entered the curved path makes a U-turn and is introduced into the rolling element return path 13, and reaches the opposite curved path through the rolling element return path 13. Here, the U-turn is made again to return to the rolling element rolling path 14, and such circulation in the rolling element circulation path is repeated infinitely.
The guide rail 1 of such a linear guide device is induction-hardened on both side surfaces 1a and 1a. As a result, a hardened layer 20 is formed on the entire surface of both side surfaces 1a and 1a including the groove surface of the rolling element rolling groove 10 (see FIG. 3). The surface hardness of the hardened layer 20 is Hv674 or higher (HRC59 or higher), and the effective hardened layer depth (distance from the surface of the hardened layer 20 to the position of Hv500) is 10% to 50% of the diameter of the rolling element 3. It is as follows.

If the surface hardness of the hardened layer 20 is less than Hv674 (less than HRC59), the rolling fatigue life is shortened, and the groove surface of the rolling element rolling groove 10 may be peeled off at an early stage, causing abnormal noise and vibration. There is.
Further, if the effective hardened layer depth is less than 10% of the diameter of the rolling element 3, there is a possibility that plastic deformation or fatigue may occur at the contact portion with the rolling element 3 due to a load applied when the linear guide device is used. is there.

This point will be described with reference to FIGS. FIG. 4 shows the distribution of hardness (unit is kgf / mm ² ) of the guide rail 1 and shear stress σ (unit is kgf / mm ²⁾ generated inside the guide rail 1 when the linear guide device is used. However, if the value of 6 times the shear stress σ (6 × σ) exceeds the hardness distribution, plastic deformation and fatigue tend to occur. For example, when the quenching hardness is low, such as the hardness 1 in FIG. 5 or when the quenching depth is not sufficient, such as the hardness 2, the value of 6 times the shear stress σ represents the hardness distribution. In some cases, it may exceed the limit, and plastic deformation and fatigue are likely to occur. Therefore, in order to prevent this, the surface hardness of the hardened layer 20 needs to be Hv674 or higher (HRC59 or higher), and the quenching depth is changed based on the effective hardened layer depth. It is necessary to make it 10% or more of the diameter of the moving body 3.

On the other hand, if induction hardening is performed under conditions that increase the quenching depth, there is a risk that the overheated state will partially occur and the strength of the region may decrease, so the quenching depth is equal to the diameter of the rolling element 3. It is necessary to make it 50% or less.
The material of the guide rail 1 is not particularly limited, but 0.5% by mass to 0.8% by mass of carbon, 0.1% by mass to 0.4% by mass of silicon, 0.5% A steel containing not less than 2% by mass of manganese and not more than 0.5% by mass of chromium as alloy components is preferred.

If the carbon content is less than 0.5% by mass, it is difficult for the surface hardness after induction hardening and tempering to be Hv674 or more (HRC59 or more), and it exceeds 0.8% by mass. And, cold workability may be insufficient. Silicon is an element that improves hardenability and needs to be 0.1% by mass or more. However, if it exceeds 0.4% by mass, cold workability may be insufficient.
Further, manganese is an element that improves hardenability, and 0.5 mass% is necessary. However, if it exceeds 2 mass%, cold workability may be insufficient. Further, chromium is an element that improves hardenability like manganese, but if it exceeds 0.5 mass%, cold workability may be insufficient.

〔Example〕
Hereinafter, the present invention will be described more specifically with reference to examples. A linear guide device having the same configuration as the linear guide device shown in FIGS. And this linear guide apparatus was driven and durability of the guide rail was evaluated. In addition, the guide rail is comprised with the steel containing the alloy component shown in Table 1. The slider is made of SCM420 and carburized.
Table 1 shows the surface hardness and effective hardened layer depth of the hardened layer formed on the guide rail. In addition, the effective hardened layer depth is shown by the ratio with respect to the diameter of a rolling element.

  The durability evaluation results are shown in Table 1. Examples 1 to 6 in which the surface hardness of the hardened layer was Hv674 or more and the effective hardened layer depth was 10% to 50% of the diameter of the rolling element were excellent in durability. On the other hand, since the surface hardness of the hardened layer or the effective hardened layer depth did not satisfy the above conditions, Comparative Examples 1 to 5 had insufficient durability.

It is a perspective view showing one embodiment of a linear guide device concerning the present invention. It is the front view which looked at the linear guide apparatus of FIG. 1 from the axial direction. It is sectional drawing of the guide rail explaining a hardened layer. It is a graph which shows distribution of the hardness of a guide rail, and distribution of the shear stress (sigma) which generate | occur | produces inside a guide rail. It is a graph which shows distribution of the hardness of a guide rail, and distribution of the shear stress (sigma) which generate | occur | produces inside a guide rail.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide rail 1a Side surface 2 Slider 3 Rolling body 10 Rolling body rolling groove 20 Hardened layer

Claims (1)

A guide rail having a rolling element rolling groove extending in the axial direction on the outer surface, a rolling element rolling groove facing the rolling element rolling groove of the guide rail, and attached to the guide rail so as to be relatively movable in the axial direction A linear guide device comprising: a slider, and a plurality of rolling elements that are arranged to freely roll between the rolling elements.
A hardened layer having a surface hardness of Hv674 or more by induction hardening is formed on the groove surface of the rolling element rolling groove, and the effective hardened layer depth is 10% to 50% of the diameter of the rolling element. Linear guide device.

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