JPH04175512A - Play prevention device between shaft and bearing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] An object of the present invention is to reduce the number of component parts and reduce the number of components in one assembly in order to reduce the assembly cost and parts cost of the play prevention mechanism between the shaft and the bearing. The goal is to provide a product structure that is easy to use.

[Prior Art] In a structure such as a carriage arm of a magnetic disk device shown in FIG.
There are cases where it is necessary to be able to position with high precision without any play, and to have a high-speed response to starting and stopping turning with as little turning torque loss as possible. In response to these demands, the inner circumference of the bearing 2 and the shaft 1
If the outer periphery of the bearing 2 and between the outer periphery of the bearing 2 and the swing arm 10 are both "tightly fit", play will not occur, but torque loss due to swing will increase.
Furthermore, if either one of the two is a loose fit, play will occur, so generally, the method shown in FIG. 6 has been commonly used.

That is, the horizontal hole 6 is provided in the axial direction of the shaft 1,
A through hole 7 having a smaller diameter than the horizontal hole 6 passes through the bottom thereof until it reaches a horizontal groove 9 provided on the opposite side of the shaft 8. A plunger 3 holding a push spring 5 is provided through these holes, and an E retaining ring 4 is attached to the rear end of the plunger 3 to prevent removal.

A bearing 2 is fitted onto this shaft 1.

A rotating member 10 is fitted on the outer periphery of the bearing 2,
It is designed to rotate around the shaft 1 (drive system omitted).

There is a tight fit between the outer circumference of the bearing 2 and the swing arm 1o, and there is a slight W between the inner circumference of the bearing 2 and the outer circumference of the shaft 1.
This requirement is met by providing RrrI and pressing the bearing 2 in one direction by the plunger 3 with the compressive force of the spring 5 to eliminate play.

[Problems to be Solved by the Invention] First of all, the above conventional structure has a large number of parts, and a push spring 5. Since it involves assembling three parts, the plunger 3 and the E retaining ring 4, it takes time to assemble and the assembly cost is high.In addition, the bearing 2 is attached to the shaft 1 with the tip of the plunger 3 protruding from the outer circumference of the shaft. It also had the disadvantage that it was difficult to insert because it fit into place.

An object of the present invention is to provide a product structure free of such imperfections.

[Means for Solving the Problems] In the present invention, a part of the shaft is removed, and the shaft is attached to this part so that it does not get in the way when inserting the bearing, and then, as the temperature rises, it exhibits its original function. By using shape memory alloy parts that deform into the shape you want.

(1) In order to reduce assembly work costs, we have created a structure that satisfies functionality even with a reduced number of component parts by using play-eliminating parts made of shape memory alloy.

(2) Achieve the ability to easily insert the bearing into the shaft with a shape that does not interfere with assembly work.

[Example] An embodiment of the present invention will be described below with reference to FIG.

A horizontal hole 6 is provided in the axial direction of the shaft 1, into which a spring plunger 11 is inserted.

This spring plunger 11 is made of shape memory alloy.
At the start of assembly, the minimum operating temperature of the device is 1, for example 0.
It is cooled to a temperature lower than ℃.

At that time, the length is shorter than the depth of the hole, as shown in the example in Figure 2, and when the temperature rises after the bearing is assembled, the shape changes as shown in Figure 1. , its length is greater than the depth of the hole.'' Therefore, the bearing 2 is pressed in a certain direction and the play is absorbed. Figure 2 (
a), (b), and (c) are examples of the shape of spring plungers before assembly. In each case, the length is shorter than the depth of the horizontal hole 6, and after assembly, it deforms as the temperature rises and the horizontal hole 6 The shape is longer than the depth. FIG. 3 is a top view of the embodiment of FIG. FIG. 4 is a diagram showing another embodiment. In this case as well, the shape of the spring plunger 11 before assembly is smaller than the depth of the groove provided in the shaft 1, as shown in FIG. After attaching, the bearing 2 will be deformed as shown in the same figure (b).
The pressing in a certain direction is the same as in the previous embodiment.

According to a cost estimate, in the example shown in FIG. 1, the assembly cost per set can be reduced by 70%. The magnitude of the effect is similar in the example shown in FIG. In addition, it is estimated that processing costs for horizontal holes or grooves on shafts will be reduced by 80%.

[Effects of the Invention] According to the present invention, the shape of the spring plunger attached to the side hole of the shaft does not protrude from the outer periphery of the shaft before assembly, so it does not interfere with the assembly of the bearing. Once assembled, the shape changes due to temperature changes, and the number of parts that firmly press the bearing in a certain direction and absorb play is reduced by two compared to conventional models, making work much easier. Become.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of the shape of the spring plunger of the present invention before assembly, and FIG. 3 is a plan view of the embodiment of the present invention. FIG. 4 is a plan view of another embodiment of the present invention, FIG. 5 is a perspective view of a magnetic disk device to which the present invention is applied, and FIG. 6 is an explanatory diagram showing an example of a conventional structure. Explanation of symbols 1...Shaft, 2...Bearing, 3...Plunger, 4...E retaining ring, 5...Press spring, 6...Horizontal hole, 7...Through hole, 8 ... Central axis of the shaft, 9...
・Horizontal groove, 10... Swivel member, 11... Spring plunger.

Claims (1)

[Scope of Claims] 1. In a device for eliminating play between the shaft and the bearing, in which the shaft and the bearing have a loose fitting structure, a member made of a shape memory alloy is interposed between the two. A device for preventing play between a shaft and a bearing. 2. A device for preventing play between a shaft and a bearing according to claim 1, wherein a member made of a shape memory alloy is used as a spring material.