JPS62215127A - Fixation of rolling bearing - Google Patents

Abstract

PURPOSE:To reduce the processing manhour and the number of parts required and also aim at the stabilization of the quality of products by placing at least either one of the inner and outer rings in a rotary shaft or a bearing bracket, and then joining the edge of its contact surface at a plurality of points sporadically by way of a laser welding. CONSTITUTION:The mounting parts 36, 38 for rolling bearings 32, 34 are processed with a high accuracy, and then, the peripheral surfaces of outer rings 32a, 34a are placed very acculately in half-case substances 28, 30 as a bearing bracket. In addition, a plurality of points G, H and I, J on the edges of these contact surfaces, and two points each intersecting perpendicularly to these are joined sporadically by means of laser beam LB. Thereby, providing a staged part and an annular groove on the rotary shaft and the bearing bracket of a rolling bearing is unnecessary anymore, and further, the processing manhour and the required number of parts can be reduced, and moreover, a high-precision positioning of the inner and outer rings, and the stabilization of the quality of products can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for fixing an inner ring or an outer ring of a rolling bearing to a rotating shaft or a bearing bracket.

(Background of the Invention) Retaining rings have conventionally been widely used when fixing the inner ring or outer ring of a rolling bearing to a rotating shaft or a bearing bracket. For example, when fixing the inner ring to the rotating shaft, two annular grooves are formed on the rotating shaft, and the inner ring is held between two retaining rings placed several times apart in each annular groove, or the inner ring is held between two retaining rings placed several times apart on the rotating shaft. Two annular grooves are formed, and the inner ring is held between the step and a retaining ring attached to the annular groove. When the outer ring is fixed to the bearing bracket, a recess deeper than the width of the outer ring is formed in the bearing bracket, and after the outer ring is fitted into the recess, a retaining ring is secured to the inner surface of the recess.

When using a retaining ring in this way, it is necessary to form an annular groove or step on the rotating shaft or bearing bladder, which not only increases the number of machining steps and the number of parts, but also makes it difficult to secure especially small bearings. In some cases, the shaft becomes longer and the bearing bracket becomes larger due to the need to attach a retaining ring or to form a step. This has been a major obstacle in promoting miniaturization.

Therefore, a method of fixing the inner and outer rings using adhesive without using a retaining ring has been conventionally used. However, in this case, between the inner ring and the rotating shaft or bearing bracket,
A gap is required to fill with adhesive. For this reason, there was a problem in that the positioning accuracy of the inner and outer rings deteriorated, and the variation in assembly accuracy of the product increased.

(Purpose of the invention) The wooden invention was made in view of these circumstances, and allows for highly accurate assembly with fewer processing steps and fewer parts.Moreover, when applied to small bearings, the assembled product can be made smaller. The purpose of this invention is to provide a method for fixing rolling bearings that is suitable for

(Structure of the Invention IR,) According to the invention, this purpose is to fit at least one of the inner ring and outer ring of a rolling bearing into a rotating shaft or a bearing bracket, and to laser beam a plurality of points on the edge of the contact surface caused by this fitting. This is achieved by a rolling bearing fixing method characterized by spot joining by welding.

(Embodiment) FIG. 1 is a diagram showing the assembly process of a small stepping motor which is an embodiment of the present invention, and FIG. 2 is a sectional view showing the assembled state.

In FIG. 1(A), reference numeral 10 denotes a rotating shaft, and this rotating shaft 10 has neither a stepped portion nor an annular groove formed therein. 12
14 is a half rotor with gears formed on its circumferential surface, and 14 is a permanent magnet. Permanent magnets 14 are positioned on the rotor shore body 12 using a jig (not shown) at multiple locations on the edge of the contact surface between the two, for example, locations A and B that are symmetrical with respect to the rotation axis 10 and at right angles thereto. A total of four locations, two locations (not shown), are irradiated with the laser beam LB, and the two are point-welded at these four locations.

This laser beam LB is produced by guiding a laser pulse emitted from a light source 16 such as a YAG laser to a condensing lens 20 via a reflecting mirror 18, and then to a lens unit 24 via an optical fiber 22.
4 also uses a laser emitted. In this case, the laser pulse emitted from the light source 16 has a pulse width of 8 IIls and an output of 6 to 8
The diameter of the melt by the laser beam emitted from the laser unit 24 is about 0.6 to 1.0 mm.

The rotor half 12 to which the permanent magnets 14 are fixed in this manner is fitted onto the rotating shaft 10, and positioned by a jig (not shown) at a plurality of locations on the edges of the contact surfaces of the two, for example C, D, and these. Two orthogonal locations are point-joined by the laser beam LB.

Thereafter, as shown in FIG. 1(B), the other rotor half 26
The rotating shaft 10 is stacked on the other side of the permanent magnet 14.
and at multiple locations on the edge of the contact surface between the two, for example, E,
Point welding is performed at F and two locations orthogonal thereto using a laser beam LB.

In FIG. 1(C), 28.30 is a case half-open as a bearing bracket, and each case 28.30 is half-open.
30 is formed with a loading portion 36.38 for mounting a rolling bearing 32.34. These loading parts 36.3
The inner surface of 8 is processed with high precision by machine cutting, etc.
The outer peripheral surfaces of the outer rings 32'a, 34a of the bearings 32, 34 are fitted with high precision. That is, the outer rings 32a, 34a
is positioned without any movement within the loading section 36,38. The loading section 36, 38 and the outer ring 32a.

34a, at multiple locations on the edge of the contact surface, for example, G, H and machining, J, and 2 locations each of g perpendicular to these, a total of 4 locations.
Each location is point-joined by the laser beam LB.

Furthermore, a stator coil 40 is fixed to the inner surface of one half-case 28 by appropriate means such as adhesive.

Next, the spacer 42 is attached to the rotating shaft 10, and this rotating shaft 1
The inner rings 32b, 34b of the bearings 32, 34 are fitted to the inner rings 32b, 34b of the bearings 32, 34, and each half case 28.30 is attached to the inner rings 32b, 34b of the bearing 32.34. Assemble as shown. Of the contact surfaces between the rotating shaft 10 and each of the inner rings 32b and 34b, the edges exposed to the outside are exposed to the laser at a plurality of locations, for example, L, M, N, and 2 locations perpendicular to these, in total. Point joining is performed by beam LB.

The stepping motor is assembled in this way, and if necessary, the pulley 44 and the like are fitted to the rotating shaft 10, and the edges of the contact surfaces of both are connected at multiple locations, for example, 0, P, and two other locations perpendicular to these. , a total of four locations are point-joined using a laser beam LB.

Since the laser beam LB is irradiated intermittently for a short time of about 8 ms, almost no deformation due to heat occurs.

Figure 3 shows the case of JIS-B-1 when the outer rings 32a and 34b are fixed to the case half-closed 28.30 by the laser beam LB.
These are experimental results showing the strain on the inner circumferential surface measured by the No. 515 test method. According to bearing standards, the inner diameter of the inner ring is 10 mm.
The radial runout is required to be within 5 gm for bearings of about 100 to 100 m, but according to the results of this experiment, the radial runout is about 1.7 pm at most, and when used in a motor, the characteristics and durability of the motor may be affected. The results show that there are no problems at all from this point of view.

In the embodiments described above, it is desirable to fix the inner ring and the rotating shaft or the case half by sequentially irradiating the laser beam LB at symmetrical positions among the four positions. For example, it is desirable to irradiate one location and then irradiate a symmetrical location in order to reduce the effects of thermal deformation. Note that if two symmetrical locations are irradiated with two laser beams at the same time, thermal deformation will be further reduced and assembly with even higher precision will be possible.

(Effects of the Invention) As described above, the present invention, when fixing the inner and outer rings of a rolling bearing to a rotating shaft or a bearing bracket, uses a laser beam to point-join the edges of the contact surfaces of the fitting portions at multiple locations. It is something. Therefore, there is no need to form a step or an annular groove on the rotating shaft or bearing bracket, reducing the number of machining steps, and since a retaining ring is not required, the number of parts can also be reduced. Furthermore, since there is no need for a space or step for attaching a retaining ring or the like, the device can be made more compact. On the other hand, unlike when using adhesive, there is no need to provide a gap to fill the adhesive, so the gap between the inner and outer rings and the rotating shaft or bearing bracket can be minimized, allowing for high accuracy between the inner and outer rings. positioning and quality stability. Note that the laser beam irradiation time is extremely short and there is very little distortion due to heat, so accuracy is further improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the assembly process of a small stepping motor according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the assembled state. Further, FIG. 3 is a diagram showing experimental results of distortion of the outer ring. 10...Rotating shaft, 28.30...Case half-open as bearing bracket, 32.34...Rolling bearing, 32a, 34a...Outer ring, 32b, 34b...Inner ring, LB...Laser beam.

Claims (1)

[Claims] A method for fixing a rolling bearing, comprising fitting at least one of an inner ring and an outer ring of the rolling bearing into a rotating shaft or a bearing bracket, and point-joining the edge of the contact surface at multiple points by laser beam welding.