JPS6318828Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a cross roller bearing in which the rolling elements are arranged to cross their axes and are inclined with respect to the axis of the bearing.

Crossed roller bearings have recently been widely used in various fields because they can carry both radial and thrust loads, but the rolling element raceway surfaces are formed in a V-shape on the opposing cylindrical surfaces of the inner and outer rings. Because it is done,
In consideration of bearing strength, etc., a hardened layer such as surface hardening or induction hardening is formed only on the raceway surface of the rolling elements.

FIG. 1 is a diagram illustrating a conventional cross roller bearing, in which 1 is an inner ring, 2 is an outer ring which is assembled by dividing into two parts in the axial direction, and 3 is a rolling element, that is, a roller. Hardened layers 6 and 7 are formed by the quenching process on the V-shaped rolling element raceway surface 4 of the inner ring 1 and the rolling element raceway surface 5 of the outer ring 2, which is formed into a V-shape by assembly. For example, as shown in FIG.
The raceway surface 5 is heated to a predetermined temperature and rapidly cooled to form a hardened layer 7, and the depth of the hardened layer 7 is shallow at both ends of the raceway surface 5. This is because the heating coil 8 as described above is used, so the hardening characteristics are as follows, and the same applies to the rolling element raceway surface 4 of the inner ring 1.

Therefore, due to the structure of the bearing, when a thrust load T acts and a moment load M is generated on the rolling elements 3,
For example, a load distribution as shown in FIG. 3 occurs on the thrust load side of the rolling element raceway surfaces 4 and 5, and the edges of the rolling element 3 (both ends of the effective length of the rolling element) touch the parts a, b, a' , the maximum load is applied near b'.
(a' and b' are the parts where the edges of the rolling elements, whose inclinations are opposite to those of the rolling elements shown in the figure, touch.) That is, excessive edge loads occur near a, b, a', and b'.

On the other hand, at both ends of the rolling element raceway surfaces 4, 5, since the quenched hardened layers 6, 7 are shallow as described above, elastic deformation occurs in which the raceway surfaces 4, 5 are bent into an arc shape due to the edge load. When the load exceeds a certain limit, plastic deformation occurs in the part of the raceway ring base material that is not affected by the quenching effect immediately behind the quench hardened layer, and the area around the a, b, a', and b' parts However, there was an inconvenience in that cracks or breaks occurred in the quenched hardened layer.

This idea prevents inconveniences such as cracks and breakage on the rolling element raceway surface, especially near both ends, even if an excessive moment load is applied to the rolling element in the above-mentioned cross roller bearing. The purpose of this is to provide a material that has sufficiently high rigidity and does not cause the occurrence of quenching, and the cylindrical surfaces of the inner and outer rings are coated in the axial direction continuously with the quenched hardened layer on the raceway surface of the rolling elements. It is characterized by forming an extending quenched hardened layer.

This invention will be described in detail with reference to the embodiment shown in FIGS. 4 and 5 below. Cylindrical surface portions 9 on both sides of the raceway surfaces continuous with the respective rolling element raceway surfaces 4 and 5 of the inner ring 1 and outer ring 2,
10, quenched hardened layers 6, 7 of the raceway surfaces 4, 5;
A method for forming such continuous hardened layers 6, 11 or 7, 12 is as shown in FIG. 5, for example. As shown in FIG. 2, the induction hardening heating coil C bent along both the rolling element raceway surface 5 and the cylindrical surface portion 10 is used to simultaneously heat the raceway surface and the cylindrical surface portion continuous thereto to a required temperature. and harden it.

Since this invention has the above-mentioned configuration, the hardened layers 11 and 1 continuous with the hardened layers 6 and 7 on both sides of the rolling element raceway surface portions applied to the cylindrical surface portions 9 and 10.
2, a thrust load is applied to the bearing, a moment load is generated on the rolling element 3, and a large edge load is applied near portions a, b, a', and b' in Fig. 3. The hardened layers 6 and 7 on the raceway surface of the rolling element are reinforced to provide sufficient yield strength to prevent the occurrence of elastic deformation in which the raceway surface is bent into an arc, thereby significantly increasing the rigidity of the raceway surface. Therefore, even with excessive edge load, plastic deformation of the non-hardened portion of the raceway ring base material can be suppressed, thereby eliminating problems such as cracks or breakage of the rolling element raceway surface due to excessive edge load. death,
Bearing life can be significantly extended.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the main parts of the conventional example, Fig. 2 is an enlarged view of the main parts, Fig. 3 is an explanatory diagram of the load acting on the rolling element raceway, and Fig. 4 is an embodiment of this invention. FIG. 5 is a longitudinal cross-sectional view showing the main parts, and FIG. 5 is an enlarged view of the same. 1...Inner ring, 2...Outer ring, 3...Rolling element, 4,
5...Rolling element raceway surface, 6, 7, 11, 12... Quenched hardened layer, 9, 10... Cylindrical surface portion.

Claims (1)

[Scope of utility model registration request] A cross roller characterized in that, on the cylindrical surface portions on both sides of the raceway surfaces that are continuous with the raceway surfaces of the rolling elements of the inner ring and the outer ring, a hardened layer is formed that extends in the axial direction and is continuous with the hardened layer of the raceway surface. bearing.