JPH1162981A - Manufacture of cage for roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To include an appropriate quantity of water in a cage to stabilize quality and to lengthen an acoustic life by injection-molding the cage using a synthetic resin, and centrifugally dehydrating after ultrasonic washing. SOLUTION: A cage is integrally formed of a synthetic resin by injection molding. In a first tank, the formed cage is submerged in water with a neutral detergent put therein, heated to 40-60 deg.C, and subjected to ultrasonic washing while being oscillated (S1). In a second tank, the cage is submerged in water of 20-40 deg.C and subjected to ultrasonic washing while being oscillated (S2). In a third tank, the cage is subjected to jet rinsing with pure water of room temperature or heater pure water while oscillating the cage (S3). The washed cage together with a washing basket is set to a centrifugal dehydrator and centrifugally dehydrated for the specified time so as to obtain a state of the cage containing a specified quantity of water (S4). The dehydrated cage is seal-packed in a polyvinyl bag or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling element of a rolling bearing used for a supporting portion of a rotating element of a precision device such as an HDD or a VTR which requires low torque, low noise, low dust generation, durability and the like. Related to the retainer.

[0002]

2. Description of the Related Art As shown in FIG. 1, for example, a rolling bearing 1 includes an outer ring 2 and an inner ring 3 having raceway surfaces 2a and 3a, respectively, and rolling elements (balls) 4. Rollably disposed between the surface 2 a and the raceway surface 3 a of the inner race 3. Further, annular seals 5 are arranged on both axial sides of the raceway surfaces 2a and 3a. The annular seal 5 prevents the lubricant from leaking to the outside of the rolling bearing 1 and prevents dust floating on the outside of the rolling bearing 1 from entering the rolling bearing 1.

A plurality of rolling elements 4 are rotatably held, for example, by a holder 6 as shown in FIG. The retainer 6 is made of, for example, a synthetic resin. Cage 6
Comprises an annular base 7 and a plurality of pillars 8 projecting from the base 7 at predetermined intervals along the circumferential direction, and is formed in an arc shape formed between adjacent pillars 8. Recess 9 constitutes a pocket for accommodating the rolling element 4. Then, by giving the column portion 8 a predetermined elasticity, each rolling element 4 is pushed between the column portions 8 and stored and held in each pocket 9.

The cage 6 having the above-described structure requires that the cage 6 be snap-fitted when the cage 6 is assembled in the assembling operation of the rolling bearing 1, that heat resistance and strength characteristics are required. Therefore, polyamide resin (PA66) is often used as a material of the cage 6. Furthermore, in order to improve the snap fit of the resin cage 6, the resin cage 6 may be subjected to a water-containing treatment using a constant temperature / humidity bath.

[0005]

However, when the rolling bearing having the above-described structure is used for a support portion of a rotating body of a precision device such as an HDD or a VTR, dust generated by a synthetic resin cage is applied to the rolling bearing. There is a problem that mixing may occur, and the possibility of occurrence of acoustic defects increases.

[0006] In the assembly work of a rolling bearing, in order to solve the acoustic defect caused by dust brought in when a synthetic resin cage is incorporated, a bearing component (outer ring, inner ring,
Although the precision cleaning of the rolling elements and the cage) is performed, the precision cleaning of the synthetic resin cage is difficult.

On the other hand, the water-containing treatment carried out to improve the snap-fitting property of the synthetic resin cage generally uses a constant temperature / humidity bath. However, in the water-containing method using the constant temperature / humidity chamber, since the steam in the constant temperature / humidity chamber is circulated by air,
There is a problem that impurities contained in dust and water in the humidity chamber may adhere to the synthetic resin retainer. Therefore, by performing the water-containing treatment, there is a possibility that a bad result that the synthetic resin cage is further stained is generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made to improve the cleanliness of a synthetic resin cage by precision water washing, and to provide a holder for filtered pure water. It is an object of the present invention to provide a synthetic resin cage having a stable quality by adjusting the amount of adhesion to a synthetic resin retainer by using a centrifugal dehydrator and making the synthetic resin retainer contain an appropriate amount of water.

[0009]

In order to solve the above-mentioned problems, a method for manufacturing a rolling bearing cage according to the present invention comprises the steps of: injection molding a rolling bearing cage having a desired shape using a synthetic resin; The method includes a step of ultrasonically cleaning the roller bearing cage with water, a step of dewatering the roller bearing cage with a centrifugal dehydrator, and a step of hermetically storing the roller bearing cage.

The synthetic resin rolling bearing cage is subjected to precision water washing with ultrasonic waves using water, and then the synthetic resin rolling bearing cage is centrifugally dehydrated to determine the amount of pure pure water deposited. After the adjustment, a predetermined amount of water is contained in the synthetic resin rolling bearing retainer.

The cage for the rolling bearing is preferably subjected to ultrasonic water washing using water heated to 20 to 60 ° C. after injection molding with a synthetic resin. The warmed water preferably contains a neutral detergent. Further, after washing with warm water containing a neutral detergent, ultrasonic cleaning may be further performed with warm water containing no neutral detergent.

Further, the roller bearing cage may be subjected to jet rinsing with clean pure water after ultrasonic cleaning. After clean pure water has adhered to the roller bearing retainer by jet rinsing, the amount of water adhered may be adjusted to an appropriate amount by a centrifugal dehydrator.

[0013] Furthermore, the cage for the rolling bearing is preferably sealed and stored in a plastic bag or the like after centrifugal dehydration, so that about 2 to 3 wt% of water is contained therein.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a cage for a synthetic resin rolling bearing according to an embodiment of the present invention. The retainer 6 includes an annular base 7 and a plurality of pillars 8 projecting from the base 7 at predetermined intervals along the circumferential direction, and is formed between adjacent pillars 8. The arc-shaped concave portion 9 forms a pocket for accommodating the rolling element. The retainer 6 is made of synthetic resin by injection molding.

FIG. 4 shows a flow of the washing step and the dehydrating step of the cage. In the first step (S <b> 1), the cage 6 contains 40 to 40 g of a neutral detergent in the first tank of the three-tank type washing device.
It is immersed in water heated to 60 ° C., and is ultrasonically cleaned while being rocked. In this cleaning step, the deposits are removed from the holder. In the second step (S2), the holder 6 is immersed in water at 20 to 40 ° C. in the second tank of the three-tank type washing apparatus, and is ultrasonically washed while being rocked. In this cleaning step, the deposits are further removed from the holder. In the third step (S3), the retainer 6 is subjected to jet rinsing with pure water at room temperature while being rocked in the third tank of the three-tank cleaning device. In this rinsing step, the cleanliness of the cage is further improved, and clean pure water adheres to the cage. In the washing and rinsing steps of the first to third steps, the cleaning liquid in the first and second tanks and the water or pure water in the third tank are caused to overflow, and suspended matter on the liquid surface is retained. You may prevent it from re-adhering to a container. In the fourth step (S4), the retainer 6 is centrifugally dehydrated, and the amount of water adhering to the retainer is adjusted. The retainer 6 has a fifth
In the step (S5), the package is hermetically sealed, and a predetermined amount of water is contained in the retainer 6. Cage 6 is about 2-3 wt%
Of water is preferably hydrated.

The acoustic level of the rolling bearing is improved by incorporating the thus obtained cage with high cleanliness into the rolling bearing. In addition, by incorporating the thus-obtained synthetic resin cage with high cleanliness into the rolling bearing, when the rotating body rotates, the adhered matter from the synthetic resin cage as in the conventional case is rolled into the rolling bearing. As a result, the acoustic lifetime is improved. In addition, the conventional constant temperature and
This eliminates the need for a humidity control step using a humidity chamber.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The resin used for the rolling bearing retainer of the embodiment of the present invention is not particularly limited, but a large snap fit property is required when a rolling element (ball) is incorporated, and therefore, a polyamide resin having excellent toughness (hereinafter, referred to as a polyamide resin). "PA resin"
That. Is preferable, and PA resin to which a reinforcing material such as glass fiber or carbon fiber is added to increase rigidity during rotation is preferable. For example, as the PA resin, "Ube Nylon" of Ube Industries, Ltd. and 46 nylon of Teijin Limited can be exemplified.

The basic configuration of the rolling bearing according to the embodiment of the present invention is the same as that of the conventional rolling bearing 1 shown in FIG. 1, and the raceway surface 2a of the outer ring 2 and the inner ring 3 which are provided on concentric circles and face each other.
The balls 4, which are a plurality of rolling elements, are arranged so as to be able to roll between the ball 4 and the raceway surface 3 a, and the balls 4 are held by a retainer 6. Annular seals 5 are disposed on both axial sides of the raceway surfaces 2a, 3a.

The retainer 6 is a crown retainer made of resin, as shown in FIG. The retainer 6 includes an annular base 7 and a column 8 protruding from the base 7 at predetermined intervals. The pockets 9 are formed by arc-shaped concave portions formed between the column portions 8, and the pockets 9 are formed.
Each ball 4 is pushed in and stored. The retainer 6 is integrally formed by injection molding using the above synthetic resin.

The retainer 6 formed by injection molding is inserted into a SUS pipe 10 or a plastic pipe shown in FIG. O-rings are inserted into both ends of the SUS pipe 10 so that the retainer does not fall off.

The holder 6 set as described above is
The entire S pipe 10 is set in a washing basket 11 as shown in FIG. 3, and the retainer 6 is washed using a three-tank type washing apparatus (manufactured by Ultrasonic Industry Co., Ltd.).

FIG. 4 shows the flow of the washing step and the dehydrating step. In FIG. 4, P indicates a pump, H indicates a heater, and F indicates a filter. The first step (S1) is an ultrasonic cleaning step. In the first tank of the three-tank type washing apparatus, the retainer 6 is immersed in water containing a neutral detergent and heated to 40 to 60 ° C., and performs ultrasonic cleaning while rocking. Second step (S
2) is a pre-rinsing step. The second of the three-tank cleaning system
In the tank, the retainer 6 is immersed in water at 20 to 40 ° C., and is subjected to ultrasonic cleaning while swinging. Third step (S3)
Is a finish rinsing step. In the third tank of the three-tank type washing apparatus, while rocking the retainer 6, pure water at room temperature or 20
A jet rinse is performed on the retainer 6 using pure water heated to ３０30 ° C. In the washing and rinsing steps of the first to third steps, the cleaning liquid in the first and second tanks (washing tank) and the water or pure water in the third tank (rinsing tank) overflow, This prevents suspended matter on the liquid surface from re-adhering to the retainer. The fourth step (S4) is a centrifugal dehydration step. The cage 6 after the washing is set together with the washing basket 11 in a centrifugal dehydrator (HM-5 manufactured by Kokusan Co., Ltd.), and the cage 6 is set at 200 to 500 rpm for 2 to 5 minutes, preferably for 2 to 3 minutes. Perform centrifugal dehydration. The rotation speed for centrifugal dehydration is preferably in the above range. If the rotation speed is too high, the amount of water adhering becomes insufficient, and the retainer 6 cannot contain a predetermined amount of water. Further, even if the treatment time is too long, the amount of water adhering to the retainer 6 is insufficient. The fifth step (S5) is a packing step. The cage 6 dehydrated by the centrifugal dehydrator is sealed and packed together with the SUS pipe 10 in a plastic bag or a unipack.

As described above, the manufacturing method of the cage for the rolling bearing according to the embodiment of the present invention comprises the steps of forming the cage → aligning the cage → cleaning the cage → dehydrating the cage → It consists of a cage packing process.

(Example 1) A method for manufacturing a cage for a rolling bearing according to the present invention is described by using an inner diameter of 5 mm, an outer diameter of 13 mm, and a width of 4 mm.
When the test was carried out using the miniature ball bearing of the present invention, the results shown in Tables 1 and 2 were obtained.

[Table 1]

[Table 2] Here, in Tables 1 and 2, the bearing of Example 1 is PA66.
A cage obtained by injection molding of a resin was used. In the first tank of the three-tank type washing apparatus, the retainer is provided with a neutral detergent 0.2.
Ultrasonic cleaning was performed for 3 minutes with 60% water containing%. In the second tank, rinsing was performed using ultrasonic waves with water at room temperature. In the third tank, a jet rinse was performed.
In each tank, rocking was performed at 10 to 20 / min. The cage after the washing is subjected to a dehydration treatment of 200 rpm × 3 minutes by a centrifugal dehydrator, and then packed in a plastic bag. After two days, the cage is assembled in a miniature ball bearing, and 15 mg of grease (lithium soap) is used as a lubricant. Enclosed.

FIG. 5 shows the relationship between the sealed storage days and the water content when the washing conditions and the centrifugal dehydration conditions of the cage were changed. The water content (wt%) at the time of centrifugal dehydration indicates a value obtained by measuring the amount of water contained and adhering to the retainer (wt%) when the cage was washed with water and centrifugally dehydrated. The water content at the time (day) indicates the water content after the elapse of the time (days) of storage in a plastic bag after centrifugal dehydration. The white circle indicates the number of rotations of 200 r after washing at a temperature of 40 ° C. for 5 minutes.
Shown is a cage dehydrated for 5 minutes at pm. The black circles are
After washing at a temperature of 40 ° C. for 10 minutes, the number of rotations is 200 rpm.
Shows the retainer dehydrated for 5 minutes. The open diamonds indicate that after washing at a temperature of 60 ° C. for 5 minutes,
Shown is a cage that has been dewatered for a minute. The black diamond indicates temperature 6
The cage after washing at 0 ° C. for 10 minutes and then spin-drying at 200 rpm for 3 minutes is shown.

(Embodiment 2) The bearing of Embodiment 2 is the same as that of Embodiment 1
The holder was subjected to ultrasonic cleaning for 3 minutes in 40 ° C. water containing 0.2% of a neutral detergent in the first tank of a three-tank type washing apparatus. The conditions of the second tank and the third tank are as follows:
This is similar to the first embodiment. The centrifugal dehydration is the same as in the first embodiment.

(Embodiment 3) The bearing of Embodiment 3 is the same as that of Embodiment 1
The holder was subjected to ultrasonic cleaning for 3 minutes in 20 ° C. water containing 0.2% of a neutral detergent in the first tank of a three-tank type washing apparatus. All other conditions are the same as in the first embodiment.

(Embodiment 4) The bearing of Embodiment 4 is the same as that of Embodiment 1
The holder was subjected to ultrasonic cleaning for 3 minutes with 60 ° C. water without a neutral detergent in the first tank of a three-tank type washing apparatus. The second tank and the third tank are the same as in the first embodiment. Centrifugal dehydration was performed at 300 rpm × 3 minutes. All other conditions are the same as in the first embodiment. Table 2 shows the water content of Examples 1-4. The amount of water contained in the retainer changes depending on the washing temperature and washing time. Example 1
3, the centrifugal dehydration conditions were the same, the washing temperature was 60 ° C,
It is different from 40 ° C. and 20 ° C., and the higher the washing temperature, the higher the water content. Further, if the cleaning temperature is the same, the longer the cleaning time, the higher the water content.

(Embodiment 5) The bearing of Embodiment 5 is the same as that of Embodiment 1
The holder was subjected to ultrasonic cleaning for 3 minutes with 40 ° C. water without a neutral detergent in the first tank of a three-tank type washing apparatus. The second tank and the third tank are the same as in the first embodiment. As the lubricant, 3 mg of an ester-based synthetic lubricating oil was attached. All other conditions are the same as in the first embodiment.

(Comparative Example 1) A test performed for the purpose of comparison with Examples 1 to 5 of the method for manufacturing a cage for a rolling bearing of the present invention is shown as a comparative example. The bearing of Comparative Example 1 uses the cage of Example 1 and heats the cage in a constant temperature / humidity chamber at a temperature of 60 ° C.
5 hours in a 90 ° C, 90% humidity atmosphere.
Without washing, 15 mg of grease (lithium soap) was sealed as a lubricant.

Comparative Example 2 The bearing of Comparative Example 2 is the same as that of Comparative Example 1.
In the same manner as in Example 1, a retainer treated with water was used, and 3 mg of an ester-based synthetic lubricating oil was attached as a lubricant.

The method of manufacturing the cage for rolling bearings of Comparative Examples 1 and 2 is as follows: a molding step of the cage → an alignment step of the cage → a humidity control step of the cage by a constant temperature / humidity tank → a packaging step of the cage. (Hereinafter referred to as a manufacturing method). This manufacturing method has fewer steps and is advantageous in terms of cost.
In the humidity control process using the constant temperature / humidity chamber, a large amount of dust and water impurities in the constant temperature / humidity chamber adhere to the synthetic resin retainer due to steam circulating in the constant temperature / humidity chamber. Rolling bearings incorporating a cage manufactured by this manufacturing method can reduce noise,
Due to large vibration and torque, it cannot be used for precision equipment such as HDD or VTR.

On the other hand, as a method of manufacturing the cage for the rolling bearing, a molding process of the cage → an alignment process of the cage → a humidity control process of the cage by a constant temperature / humidity bath → a washing process of the cage → drying of the cage. A manufacturing method including a process-> a cage packing process can be considered (hereinafter, referred to as a manufacturing method). This manufacturing method, after the humidity control step of the cage by the constant temperature and humidity chamber,
Most of the deposits on the cage can be removed by the cleaning process of the cage.However, in order to clean the cage with many stains, the cleaning liquid is extremely dirty and it is not possible to stably supply the cage with high cleanliness. Have difficulty.

The acoustic performance of Examples 1 to 5 and Comparative Examples 1 and 2 was evaluated. With a preload of 2 kg · f,
The inner ring was rotated at 3600 rpm, and Anderon values in the middle band (Mid Band: around 1000 Hz) and the high band (HiBand: 1000 Hz or more) at the initial stage of rotation were measured. Table 1 shows the initial anderon values. The acoustic test was performed by installing an inner ring rotation test device in a thermostat and maintaining the temperature at 65 ° C. to perform the rotation test. The acoustic life in the rotation test was a time until the anderon value in the middle band exceeded 2.5 anderon. Table 1 shows the acoustic lifetime.

Here, the Anderon value is measured by an Anderometer. The Anderometer is a vibration measuring device for finished bearings manufactured by Micrometrical Manufacturing Co. in the United States. This measuring device measures the radial vibration of the bearing outer ring during rotation of the inner ring. Radial vibration of the outer ring of the bearing is detected by the converter,
The output is divided into three frequency bands and expressed in units called Anderon. The three bands are Low Band, Me
dium Band and High Band, and the frequency of each band is
50 to 300 Hz, 300 to 1800 Hz, 1
800 to 10000 Hz. The unit called Anderon is shown as follows. Anderon = V / (n√N) Here, V is the root mean square value of the velocity of the vibration component included in the bandwidth among the radial vibrations of the outer ring (unit: μin /
s), n is the rotation speed of the inner ring (unit: rad / s), N is
It is the octave number of the measurement band.

[0036]

The present invention is embodied in the form described above and has the following effects. As can be seen from Table 1, when the lubricant under the same conditions is used, the bearings of Examples 1 to 5 are better than the bearings of Comparative Examples 1 and 2.
It can be seen that the initial acoustic characteristics are good and the acoustic life is improved. As described above, in the bearing using the synthetic resin rolling bearing retainer manufactured by the manufacturing method of the present invention, there is almost no dust or dirt in the bearing, and the rolling element (ball) and the raceway surface are not in contact with each other. There is no foreign matter biting in between,
The sound is reduced and the lubricant is not contaminated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a rolling bearing according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a retainer according to the embodiment of the present invention.

FIG. 3 is a view showing a cage and a set of the cage according to the embodiment of the present invention;

FIG. 4 is a diagram showing a flow of a cleaning step and a dehydrating step of the retainer according to the embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the sealed storage days and the water content when the washing conditions and centrifugal dehydration conditions of the cage according to the embodiment of the present invention are changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Outer ring 2a raceway surface 3 Inner ring 3a raceway surface 4 Rolling element 5 Seal 6 Cage 7 Circular base 8 Column part 9 Pocket 10 SUS pipe 11 Cleaning basket

Claims (1)

[Claims] 1. A step of injection molding a cage for a rolling bearing having a desired shape using a synthetic resin; a step of ultrasonically cleaning the cage for a rolling bearing with water; and a step of cleaning the cage for a rolling bearing. A method for producing a rolling bearing retainer, comprising: a step of dehydrating with a centrifugal dehydrator; and a step of hermetically storing the rolling bearing retainer.