JPH05118325A - Pre-load application device of ball bearing and its pre-load application - Google Patents

Abstract

PURPOSE:To provide a pre-load application device of a ball bearing to precisely apply pre-load without receiving influence of slide friction loss and its application method. CONSTITUTION:In a pre-load application device of a ball bearing with an elastic body 5 to previously apply pressure to the ball bearing at the time of assembly, an oscillation element 8 to superimpose a damped oscillation component to this pre-load is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing preload application device for applying an appropriate preload to a ball bearing such as a motor and a preload application method thereof.

[0002]

2. Description of the Related Art As a method of applying a preload to a ball bearing, there are a constant pressure preload and a constant position preload. The constant pressure preload is a method of applying a preload in which a spring is built in a motor together with a ball bearing, and a predetermined pressure is constantly applied to the ball bearing by the spring. A space for a spring is required in the motor, which is not suitable for a compact and thin motor. Moreover, there is a problem that the spring becomes weaker over time and the preload decreases.

The fixed position preload is applied from the outside to the ball bearing with a spring or the like during assembly, the ball bearing is fixed in the applied state, and a predetermined preload of the ball bearing is applied even after the pressure of the spring or the like is removed. Is the way to do it. There are cases where a preload is applied to the inner ring of the ball bearing and cases where it is applied to the outer ring. The present invention includes a case where a preload is applied to both the inner ring and the outer ring, and particularly relates to a fixed position preload for applying a pressure from the outside. Hereinafter, a method of applying a preload to the inner ring of the ball bearing will be described with reference to the drawings.

FIG. 3 is an enlarged sectional view of a ball bearing portion of the motor 20, for example. The motor 20 includes first and second ball bearings 21, 22, a motor shaft 23, and a stator portion 2
4, having a rotor portion 25. For ease of explanation, illustration of windings and magnets necessary for the motor 20 is omitted,
Only the ball bearing portion is shown. Stator part
24 has a central convex portion 24a, and the motor shaft 23 is erected on the central convex portion 24a of the stator portion 24. The inner rings of the first and second ball bearings 21 and 22 are mounted on the motor shaft 23, and the inner ring of the second ball bearing 12 is in contact with the central convex portion 24a of the stator portion 24. The rotor 25 has an annular protrusion
The outer races of the first and second ball bearings 21 and 22 having 25a are inserted into the rotor portion 25 with the annular convex portion 25a interposed therebetween.

The pressure which is the preload is first applied to the inner ring of the first ball bearing 21. When pressure is applied to the inner ring of the first ball bearing 21, pressure is applied to the outer ring of the first ball bearing 21 via the balls of the first ball bearing 21. Pressure is applied from the outer ring of the first ball bearing 21 to the outer ring of the second ball bearing 22 via the annular convex portion 25a of the rotor portion 25, and the second ball bearing
Pressure is applied to the inner ring of the second ball bearing 22 through the balls of 22. Since the inner ring of the second ball bearing 22 is in contact with the central convex portion 24a of the stator portion 24, a preload is applied from the inner ring of the first ball bearing 21 to the inner ring of the second ball bearing 22. ..

A device for applying a preload will be described with reference to the sectional view of FIG. In FIG. 4, 20 is a motor to which the preload described in FIG. 3 is applied. The reference numerals described in FIG. 3 are not added in FIG. 4, but will be described including the reference numerals in FIG. The preload applying device has a base 31, a guide 32 is provided upright on the base 31, and a slider 33 can reciprocate on the guide 32. A support plate 34 is arranged on the slider 33, and the support plate 34 applies downward pressure to the pressure sensor 36 and the drive shaft 37 via the spring 35 to press the inner ring of the ball bearing 21 of the motor 20. .. In this state, the inner ring of the ball bearing 21 is fixed to the motor shaft 23 with an adhesive. After the adhesive is hardened, the slider 33 is moved upward, the drive shaft 37 is separated from the motor 20, and the motor 20 to which the preload is applied is obtained.

Ball bearings 21, 22 to which preload is applied
Since there is a sliding friction loss between the inner ring and the motor shaft 23,
The actually applied preload becomes smaller than the target preload magnitude. In FIG. 5, the target preload is indicated by reference numeral 41, the pressure detected by the pressure sensor (actually applied pressure) is indicated by reference numeral 42,
The reference numeral 43 represents the actually applied preload. Even when the pressure 42 of the pressure sensor reaches the target pressure 41, the actually applied preload 43 becomes low.

Therefore, in consideration of the sliding friction loss, the applied pressure (pressure detected by the pressure sensor) 42 is made larger than the target preload 41 as shown in FIG. Since the sliding friction loss is not constant, the preload 43 actually applied has a variation A, and it is difficult to apply an appropriate preload even by this method.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a preloading device for a ball bearing and a method of applying the same, which is not affected by sliding friction loss and more accurately applies a preload.

[0010]

SUMMARY OF THE INVENTION According to the present invention, in a preload applying device for a ball bearing having an elastic body for preliminarily applying pressure to the ball bearing during assembly, a vibrating element for superposing a damping vibration component on the preload is provided. Characterize. The method of applying a preload to a ball bearing according to the present invention is a method of applying a pressure to the ball bearing in advance during assembly, fixing the ball bearing at the position of the applied state, and applying a preload to the ball bearing. It is characterized by superposing the vibration component.

[0011]

By superposing the damping vibration component on the preload in this manner, the influence of sliding friction loss between the inner ring of the ball bearing and the motor shaft is eliminated, and an accurate preload can be applied.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described in the prior art, the present invention relates to a ball bearing preload application device for applying a fixed position preload, and a method for applying the preload.
As described with reference to FIG. 3, the reference numeral 20 includes the first and second ball bearings 21 and 22, the motor shaft 23, the stator portion 24, and the rotor portion 25.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of an embodiment of a preload applying device for a ball bearing according to the present invention, and FIG. 2 is a target preload of the present invention, a preload detected by a pressure sensor, and an actual applied preload with respect to time. It is a figure which shows change. In FIG. 1, 20 is a motor to which the preload described in FIG. 3 is applied. The reference numerals described in FIG. 3 are not added in FIG. 1, but the reference numerals in FIG. The preload applying device of the present invention has a base 1, a guide 2 is provided upright on the base 1, and a slider 3 can reciprocate on the guide 2. This slider 3 has a support plate 4
The support plate 4 applies downward pressure to the pressure sensor 6 and the drive shaft 7 via the spring 5 made of an elastic body to press the inner ring of the ball bearing 21 of the motor 20. In this state, set the inner ring of the ball bearing 21 to the motor shaft.
Fix to 23 with adhesive. After the adhesive is hardened, the slider 3 is moved upward, the drive shaft 7 is separated from the motor 20, and the motor 20 to which the preload is applied is obtained.

A feature of the present invention is that a vibrating element 8 composed of a piezo element is provided between the pressure sensor 6 and the drive shaft 7. The vibrating element 8 superimposes a damping vibration component on the preload. The damping vibration is applied with an appropriate magnitude when the preload is applied, and is damped with time. In FIG. 6, when the target preload is 11 and the pressure detected by the pressure sensor is 12, the actually applied preload changes as 13.
Over time, the actual applied preload 13 matches the target preload 11.

The present invention is not limited to the preload applying device described here, but includes a preload applying method for the ball bearing. That is, it is a method of applying a pressure to the ball bearing in advance at the time of assembly, fixing the ball bearing at the position of the applied state, and applying a preload to the ball bearing, wherein a damping vibration component is superimposed on the preload. It also includes a method of applying a preload to the ball bearing.

The elastic body has been described as an example of a spring, but the elastic body is not limited to a spring, and may be rubber, air pressure,
It can be used if it has elasticity such as hydraulic pressure.

[0017]

As described above, according to the present invention, the influence of sliding friction loss between the inner ring of the ball bearing and the motor shaft is eliminated by superposing the damping vibration component on the preload applied to the ball bearing. It is possible to obtain a preload applying device for a ball bearing which can apply an accurate preload and a preload applying method thereof.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a preloading device for a ball bearing according to the present invention.

FIG. 2 is a diagram showing a temporal change of a target preload of the present invention, a preload detected by a pressure sensor, and an actually applied preload.

FIG. 3 is an enlarged sectional view of a ball bearing portion of a motor.

FIG. 4 is a sectional view of a conventional preloading device.

FIG. 5 is a diagram showing a temporal change of a conventional target preload, a preload detected by a pressure sensor, and an actually applied preload.

FIG. 6 is a diagram showing changes over time in conventional target preload, pressure detected by a pressure sensor, and variations in actually applied preload.

[Explanation of symbols]

 1 base 2 guide 3 slider 4 support plate 5 elastic body (spring) 6 pressure sensor 7 drive shaft 8 vibrating element 11 target preload 12 preload detected by pressure sensor 13 actual preload 20 motor 21, 22 ball bearing 23 Motor shaft 24 Stator part 24a Central convex part 25 Rotor part 25a Annular convex part

Claims (2)

[Claims] 1. A preloading device for a ball bearing having an elastic body for preliminarily applying pressure to the ball bearing during assembly, wherein a vibrating element for superposing a damping vibration component on the preload is provided. apparatus. 2. A method for applying pressure to a ball bearing in advance during assembly, fixing the ball bearing at the position of the applied state, and applying a preload to the ball bearing,
A preloading method for a ball bearing, characterized in that a damping vibration component is superimposed on this preload.