JP2874388B2 - Preload measurement method for rolling ball bearings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the preload of a rolling ball bearing having a ball interposed between an inner ring and an outer ring, and provides a method which can be measured in a short time with a simple structure. Things.

[0002]

2. Description of the Related Art Conventionally, at the time of assembling a rolling ball bearing, for example, as shown in FIG. 3, two sets of balls 2 each having a ball 5 between an inner ring 3 and an outer ring 4 are mounted on a shaft 2 held on a receiving base 1. A bearing is inserted in a state where a spring washer 6 is interposed between the outer rings 4, and then a predetermined pressure F is applied to one of the inner rings 3 in the longitudinal direction of the shaft 2.
In other words, each inner ring 3 is
And the ball 5 is held between the inner race 3 and the outer race 4 without any gap.

[0003] The magnitude of this preload affects the rotational accuracy of the bearing, rotational noise, frictional moment, temperature rise of the bearing due to rotation, and the like, and it is necessary to precisely regulate the bearing according to the purpose.

Conventionally, in a manufacturing process or the like, an apparatus shown in FIG. 4 has been used as a method for checking whether or not an assembled rolling ball bearing as shown in FIG. 3 has a predetermined preload.

In FIG. 4, reference numeral 7 denotes a motor which rotates at a constant speed, 8 denotes a connect coupler for detachably connecting a rotating shaft 7a of the motor 7 and a shaft 2 (inner ring 3) of a bearing to be measured,
Reference numeral 9 denotes a cap detachably connected to the outer ring 4,
0 is coupled to the force gage 11.

In the above configuration, when the bearing loss torque is measured by the force gauge 11 while the inner ring 3 is rotated at a constant speed by the motor 7, as shown in FIG. It stabilizes after a predetermined time has elapsed.

Since the correlation between the bearing loss torque value and the preload value is extremely high, it is possible to determine whether the preload value is a predetermined value by measuring the bearing loss torque value.

[0008]

However, in the above method, several minutes are required until the bearing loss torque is stabilized. Therefore, it takes a lot of time to measure a large amount of preload of the bearing of a mass-produced small motor. I needed it.

[0009]

According to the present invention, there is provided a method for measuring the preload of a rolling ball bearing which solves the above-mentioned problem by relatively rotating one of the inner ring and the outer ring of the rolling ball bearing to be measured and then stopping. The static friction torque between the inner ring and the outer ring at the time of the stop is measured, and the preload of the rolling ball bearing is obtained from the measured value.

[0010]

The inventor of the present invention stops one of the inner and outer races of a rolling ball bearing after rotating them relatively, and measures the static friction torque between the inner and outer races of the bearing when the bearing is stopped. Has a high correlation with the preload value of the bearing, and the measured value is not greatly affected during the rotational driving period, and a stable static friction torque value can be obtained even when stopped and measured after a short period of rotational driving Was confirmed as a result of the experiment.

FIG. 2 shows a mineral ball bearing JI.
The preload value of S-684ZZ is 0.5kg, 1.0kg, 1.
The figure shows the results of measuring the bearing loss torque and the static friction torque during the operation of changing to 5 kg and 2.0 kg, rotating for 5 seconds and stopping for 5 seconds in each state 10 times.

As apparent from FIG. 2, the driving period is 5
Even in a short period of time, the static friction torque A at the time of the subsequent stop becomes a substantially constant value according to the preload value.

The present invention estimates the bearing preload value by measuring the static friction torque value based on this result.

As shown in FIG. 2, a stable measurement result can be obtained only by driving for a short period of time as shown in FIG.
The measurement can be performed much faster than the conventional measurement of the bearing loss torque.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus used in the measuring method of the present invention, and has almost the same configuration as the apparatus shown in FIG.

The difference is that the motor 7 is automatically stopped after a predetermined time T (for example, 5 seconds) has elapsed from the start of driving of the motor 7 at the time of measurement, and the brake 12 Thus, by measuring the static friction torque with the force gauge 11 in a state where the braking is applied, the static friction torque can be measured more accurately.

During the driving period T, the rolling ball bearing rotates, and grease solids and contaminants in the ball raceway inside the bearing move out of the ball raceway. This period is necessary to reduce the measurement error of static friction torque caused by foreign substances. It is necessary to lengthen it when the viscosity of the used grease is high, but it is 5 seconds for general small bearings. The values before and after are sufficient.

The preload value of the bearing to be measured can be known by comparing the value of the static friction torque measured as described above with the value of the static friction torque measured by changing the preload value in advance. Things.

[0020]

As described above, according to the present invention, the preload value can be measured by driving the bearing to be measured in the conventional manner for several seconds without driving the bearing for several minutes. This is convenient for measuring a large amount of preload value of the bearing.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of one embodiment of a measuring device used in a method for measuring a preload of a rolling ball bearing according to the present invention.

FIG. 2 is a diagram showing a relationship between a preload value of a rolling ball bearing and a static friction torque.

FIG. 3 is a side sectional view of a rolling ball bearing in an assembling process.

FIG. 4 is a partially cutaway side view of a measuring device used in a conventional preload measuring method.

FIG. 5 is a diagram showing a relationship between a bearing loss torque of a rolling ball bearing and a driving period.

[Explanation of symbols]

 2 shaft 3 inner ring 4 outer ring 5 ball 7 drive motor 8 connect coupler 9 cap 10 thread 11 force gage 12 brake

Claims (1)

(57) [Claims] 1. A rolling ball bearing having a ball interposed between an inner ring and an outer ring, which is relatively driven to rotate one of the inner and outer rings of the rolling ball bearing to be measured, and then stopped, and the stationary between the inner and outer rings at the time of the stop. A method for measuring a preload of a rolling ball bearing, wherein a friction torque is measured, and a preload of the rolling ball bearing is obtained from the measured value.