JP2000199519A - Washing method of dynamic pressure bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean an inner circumferential surface extremely good by immersing a cylindrical dynamic pressure bearing in a washing liquid so that an opening direction is directed to a substantially vertical direction, and ultrasonically wasing the inner surface with a ultrasonic application means separated by a specified distance or below from an end surface. SOLUTION: A plurality of dynamic pressure bearings 30 are arranged at a substantially equal height horizontally in a retaining plate 23 inside of a washing tank containing a washing liquid 21 so that the opening direction of a. bearing hole 33 may be directed to a substantially perpendicular direction. The relationship between a pair of ultrasonic wave application means 10, 10' and the retaining plate 23 is preliminarily set so that distances W1, W2 between upper and lower end faces of the bearing 30 and upper and lower horns 14, 14 may be not more than 15 mm. When it is less than 15 mm, a required washing effect is obtained, but when it is too short they are brought into contact with each other to generate mechanical noise, and thereby the distance is desirably 5-15 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for cleaning a dynamic pressure bearing. More specifically, the present invention relates to a method for cleaning a dynamic pressure bearing using an ultrasonic wave applying means.

[0002]

2. Description of the Related Art When a cylindrical dynamic pressure bearing is formed by performing predetermined machining, fine machining chips adhere to the surface of the dynamic pressure bearing together with processing oil. In particular, since a dynamic pressure generating groove for generating dynamic pressure is formed at a depth of several μm on the inner peripheral surface of the dynamic pressure bearing, machining debris remains in such a dynamic pressure generating groove. In such a case, a smooth bearing operation cannot be performed. Therefore, the following method has been adopted in order to clean the processing debris attached to the inner peripheral surface of the dynamic pressure bearing.

That is, as shown in FIG. 6, a cleaning tool 50 having a brush 51 at the tip of a handle 52 is prepared.
After applying a fine abrasive such as toothpaste to 1, the cleaning tool 50 is inserted into the bearing hole 33 of the dynamic pressure bearing 30. Then, the operation of moving the cleaning tool 50 in the vertical and rotational directions is repeated several times, whereby the bearing hole 33 is cleaned. It should be noted that such a cleaning operation can be handled by either a manual operation or an automatic operation. Further, the processing dust attached to the surface other than the inner peripheral surface of the bearing hole 33 can be easily wiped off with a cloth or the like.

However, according to such a cleaning method using the cleaning tool 50, the cleaning tool 50 must be inserted into the bearing hole 33 of the dynamic pressure bearing 30, which is the object to be cleaned, and cleaned each time. The workability is inferior and the cleaning time becomes long. In addition, there is a limit to the cleaning accuracy, and the amount of processing waste remaining after cleaning reaches an average of 8000 pieces / cm ² .
Also, since the same cleaning tool 50 is used many times,
A large number of processing chips are accumulated inside the brush 51, and the inner peripheral surface of the bearing hole 33 is damaged by the influence of the processing chips. Further, a fine abrasive such as toothpaste may contain a component that promotes generation of rust and harmful gas in some cases.
Therefore, cleaning using the cleaning tool 50 is not suitable for cleaning a dynamic pressure bearing.

[0005] Instead of such a cleaning method, a method using an ultrasonic cleaning device is known as a method for cleaning a machined part with high accuracy. This is done by immersing the ultrasonic wave applying means in the cleaning liquid contained in the cleaning tank, irradiating the object to be cleaned placed in the cleaning liquid with ultrasonic vibrations, and removing the processing debris adhering to the surface of the object to be cleaned. This is a method of cleaning the processing oil.

[0006]

However, when cleaning a cylindrical dynamic pressure bearing using an ultrasonic cleaning device, the dynamic vibration bearing is randomly arranged in the cleaning liquid in the cleaning tank to reduce the ultrasonic vibration. When the irradiation is performed, the ultrasonic vibration does not propagate to the outer peripheral surface and the inner peripheral surface of the bearing with a uniform size, and there is a possibility that the cleaning accuracy becomes uneven. In particular, in the case of a cylindrical dynamic pressure bearing, if the inner peripheral surface on which the dynamic pressure generating groove is formed is not sufficiently washed, a shaft such as an electric motor cannot be smoothly hindered. .

[0007] In view of the above problems, an object of the present invention is to provide a cleaning method for cleaning the inner peripheral surface of a dynamic pressure bearing using an ultrasonic wave applying means in an extremely good manner.

[0008]

In order to solve the above-mentioned problems, the present invention is directed to immersing a cylindrical dynamic pressure bearing having a dynamic pressure generating groove in a cleaning liquid accommodated in a cleaning tank, and immersing the cylindrical hydrodynamic bearing in the cleaning liquid. A washing method for washing the dynamic pressure bearing by immersing sound wave application means, wherein the dynamic pressure bearing is immersed in the cleaning liquid such that an opening direction of the cylindrical dynamic pressure bearing is substantially vertical. The ultrasonic wave generated by the ultrasonic wave applying means is transmitted to the dynamic pressure bearing for cleaning in a state where the ultrasonic wave applying means is separated from the end face of the dynamic pressure bearing by 15 mm or less.

According to the present invention, ultrasonic cleaning is performed by separating the ultrasonic applying means to 15 mm or less from the end face of the dynamic pressure bearing immersed in the cleaning liquid so that the opening direction is substantially vertical. Therefore, the ultrasonic vibration is directly propagated to the inner peripheral surface of the dynamic pressure bearing with a substantially uniform size. Therefore, the inner peripheral surface of the bearing having the dynamic pressure generating groove can be cleaned well.

In the present invention, it is preferable that the cleaning is performed while the dynamic pressure bearing or the ultrasonic wave applying means is relatively moved in the horizontal direction.

When the cleaning is performed as described above, the excitation is performed while the positional relationship between the dynamic pressure bearing and the ultrasonic wave applying means is relatively changed, so that the ultrasonic wave is transmitted from a specific direction to the surface of the dynamic pressure bearing. Without this, the ultrasonic vibration is continuously and directly propagated evenly over the surface of the dynamic pressure bearing, and the cleaning can be performed efficiently and with high accuracy.

In the present invention, when the cylinder length of the dynamic pressure bearing is not more than twice the inner diameter, the ultrasonic wave applying means is closely opposed from one side of the opening of the dynamic pressure bearing. When the cylinder length is more than twice as large as the inner diameter, it is preferable that the ultrasonic wave applying means be closely opposed from both sides of the opening of the dynamic pressure bearing.

A dynamic pressure generating groove is formed on the inner peripheral surface of the cylindrical dynamic pressure bearing. By oscillating the sound wave applying means in close proximity to each other, foreign matter attached to the dynamic pressure generating groove can be washed with high precision. Therefore, it is possible to perform high-precision cleaning with the minimum necessary number of ultrasonic wave applying means, and it is possible to suppress a rise in cleaning equipment. On the other hand, when the cylinder length of the dynamic pressure bearing is more than twice the inner diameter, the ultrasonic wave may be attenuated inside the bearing hole and may not be transmitted in a uniform size over the entire inner peripheral surface. By adhering the ultrasonic wave applying means from both sides of the opening of the dynamic pressure bearing, dirt adhering to the dynamic pressure generating groove can be reliably washed.

The present invention is characterized in that a surfactant or a detergent having a dissolving power is added to the cleaning solution. As a result, the interfacial tension of the cleaning liquid decreases,
The cleaning liquid reliably reaches the bottom of the dynamic pressure generating groove formed at a very small depth. Therefore, the dynamic pressure generating groove can be cleaned with extremely high precision by the excited cleaning liquid.

Further, according to the present invention, a cylindrical dynamic pressure bearing having a dynamic pressure generating groove is immersed in a cleaning liquid contained in a cleaning tank, and an ultrasonic wave applying means is immersed in the cleaning liquid to form the dynamic pressure bearing. A method of cleaning a dynamic pressure bearing to be cleaned, wherein a horn insertable into a bearing hole of the dynamic pressure bearing is provided in the ultrasonic wave applying means, and the horn is moved when the horn is moved in one direction. A bearing holder for holding the dynamic pressure bearing at a position where the horn can be inserted into the bearing hole is arranged in the cleaning tank, and the dynamic pressure bearing is immersed in the cleaning liquid.
Ultrasonic waves generated by the ultrasonic wave application means are transmitted to the dynamic pressure bearing for cleaning while the horn is inserted into the bearing hole.

As described above, since the horn is excited with the horn inserted into the bearing hole of the dynamic pressure bearing, the ultrasonic wave is surely propagated into the bearing hole of the dynamic pressure bearing where propagation is relatively difficult, and the dynamic pressure is generated. The grooves can be cleaned with extremely high precision.

[0017]

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

FIG. 1 is a view showing an ultrasonic cleaning apparatus used in the cleaning method according to the present invention. In FIG. 1, the ultrasonic cleaning apparatus mainly includes a cleaning tank 20 containing a cleaning liquid 21.
And an ultrasonic wave applying means 10. The cleaning liquid 21 is an aqueous solution in which 0.001% to 0.1% of a surfactant such as a neutral detergent or a detergent having a dissolving power is dissolved in city water as a main component. A support plate 23 having a plurality of through holes 23a is provided in the cleaning liquid 21, and a dynamic pressure bearing 30 is loosely fitted in each of the through holes 23a.
These dynamic pressure bearings 30 are held so that the height in the horizontal direction is substantially uniform.

FIG. 2 is a cross-sectional view of the dynamic pressure bearing 30 to be cleaned in this embodiment. The dynamic pressure bearing 30 includes a housing 32 made of an aluminum alloy or the like, and a cylindrical sleeve 31 made of a SUS material or the like fitted and fixed to the housing 32. A bearing hole 33 is formed through the center of the sleeve 31, and a herringbone-shaped dynamic pressure generating groove 31 a is formed in the inner peripheral surface of the sleeve 31 so as to be axially separated and formed by a method such as rolling or etching. Have been. The inner diameter D of the bearing hole 33 is approximately 3 mm to 10 m.
m and the length L of the bearing hole 33 are appropriately set within a range of 10 mm to 50 mm. The bearing hole 33 of the dynamic pressure bearing 30
On the inner peripheral surface, outer peripheral surface, and both end surfaces, foreign substances (not shown) such as processing chips and cutting oil generated during processing adhere.
These foreign substances are cleaned by a cleaning method described later.

Returning to FIG. 1, the ultrasonic wave applying means 10 includes an ultrasonic oscillator 11 and
1 is provided with a vibrator 12, a cone 13 connected to the vibrator 12, and a horn 14 having one end connected to the cone 13 and the other end reaching the cleaning liquid 21. In the embodiment shown in FIG. 1, two ultrasonic wave applying means 10 and 10 'are provided. That is, the one ultrasonic application means 10 is provided above the cleaning tank 20 in a state where the horn 14 stands upright toward the cleaning liquid 21 side,
The other ultrasonic applying means 10 ′ is installed with the tip of the horn 14 protruding into the cleaning liquid 21 via sealing means 22 such as an O-ring attached to the bottom of the cleaning tank 20. I have. These ultrasonic applying means 10, 1
Although 0 ′ is fixedly installed in the cleaning tank 20 in an immovable state, the upper ultrasonic wave applying means 10 may be set so as to be movable in the horizontal direction.

The vibrator 12 is formed of a piezoelectric material or the like, and the frequency generated by the ultrasonic oscillator 11 is 1
Receiving an ultrasonic electric signal of 5 kHz to 100 kHz,
Convert to vibration energy. The cone 13 has a flange 1
The vibration energy is fixed to a main body (not shown) via 3a, and the vibration energy is enlarged to a predetermined magnitude (amplitude). The horn 14 is made of a material having low vibration attenuation such as a metal, and further propagates the vibration energy expanded by the cone 13 to the cleaning liquid 21.

The vibration energy transmitted to the cleaning liquid 21 is transmitted to the dynamic pressure bearing 30 immersed in the cleaning liquid 21. Then, ultrasonic vibration occurs in the dynamic pressure bearing 30,
A relative movement occurs between the surface of the dynamic pressure bearing 30 and the cleaning liquid 21. Due to such relative movement, intense friction occurs at the interface between the dynamic pressure bearing 30 and the cleaning liquid 21. As a result, foreign matter adhering to the surface of the dynamic pressure bearing 30 is removed.

Next, a method of cleaning the dynamic pressure bearing 30 using the above-described ultrasonic cleaning apparatus will be described. First, as shown in FIG. 1, a bearing hole 33 provided in the dynamic pressure bearing 30 is provided.
The plurality of dynamic pressure bearings 30 are arranged on the holding plate 23 in the cleaning tank 20 in which the cleaning liquid 21 is stored so that the opening direction is substantially vertical. At this time, since the holding plate 23 is flat, the dynamic pressure bearings 30 are arranged at a substantially uniform height in the horizontal direction. Moreover, the holding plate 2
3 and the lower horn 1
4 and the distance W2 between the upper end face of the dynamic pressure bearing 30 and the upper horn 14 are each 15 mm or less, and the positional relationship between the pair of ultrasonic wave applying means 10 and 10 ′ and the holding plate 23. Is set in advance.

The tip surface of each horn 14 and the dynamic pressure bearing 30
If the distance to the end face is 15 mm or less, a desired cleaning effect can be obtained. However, if the horn 14 and the dynamic pressure bearing 30 are too close to come into contact with each other, mechanical noise is generated and metal contact occurs. Since both may be damaged,
The interval is preferably 5 mm to 15 mm. In the present embodiment, the holding plate 23 is configured to be horizontally movable by a driving source (not shown). Therefore, when the drive source is started after the predetermined number of the dynamic pressure bearings 30 are arranged on the holding plate 23, the vertical distance between the horn 14 and the dynamic pressure bearing 30 is always 5 mm to 15 mm.
The holding plate 23 moves in the horizontal direction while being held at the position.

Thereafter, the ultrasonic wave applying means 10 is activated to start the excitation of the cleaning liquid 21. However, the excitation may be started prior to the moving operation of the holding plate 23 holding the dynamic pressure bearing 30. Ultrasonic vibrations emitted upon activation of the ultrasonic wave applying means 10 are transmitted to the dynamic pressure bearing 30 via the cleaning liquid 21. At this time, ultrasonic vibration is generated in the dynamic pressure bearing 30, and relative movement occurs between the surface of the dynamic pressure bearing 30 and the cleaning liquid 21. Due to this relative movement, the dynamic pressure bearing 3
Friction occurs at the interface between the cleaning fluid 21 and the cleaning fluid 21, and as a result, foreign matter adhered to the surface of the dynamic pressure bearing 30 is removed. In addition, the opening direction of the dynamic pressure bearing 30 is substantially vertical, and the cone 14 of the ultrasonic wave applying means 10 is closely opposed to one end of the dynamic pressure bearing 30 at an interval of 5 mm to 15 mm. The light propagates along the opening direction of the bearing hole 33 with almost no attenuation.

Since a surfactant or a neutral detergent having dissolving and dispersing power is added to the cleaning liquid 21, the interfacial tension of the cleaning liquid 21 decreases. As a result, the cleaning liquid 21 reaches the bottom of the dynamic pressure generation groove 31a formed at a depth of several μm.
Will definitely arrive. Therefore, the dynamic pressure generating groove 31a can be cleaned with extremely high precision.

The ultrasonic wave applying means 10 is
Is preferably 10 seconds to 60 seconds per unit. That is, if the excitation time is about 60 seconds, the foreign matter on the bearing surface is almost completely removed, while if the excitation time is less than 10 seconds, the amount of the foreign matter may be 300 pieces / cm ² or more. This is because it may not be obtained. Also,
When the ultrasonic wave applying means 10 is excited while being closely opposed to the dynamic pressure bearing 30, the holding plate 23 holding the dynamic pressure bearing 30 may be in the stationary state or in the moving state, and may be in the proximity state. With 10 seconds to 60 seconds, the amount of foreign matter can be suppressed to less than 300 particles / cm ² .

The cylinder length L of the bearing hole 33 of the dynamic pressure bearing 30
When (see FIG. 2) is more than twice the inner diameter D of the bearing hole 33, that is, when L / D> 2, both sides of the opening of the dynamic pressure bearing 30 as in the cleaning device shown in FIG. The ultrasonic wave applying means 10 and 10 'are installed in the apparatus to excite ultrasonic waves from both openings. This makes it possible to remove foreign matter attached to the bearing hole 33 with high accuracy in a short time. When cleaning the hydrodynamic bearing 30 having such a shape, the ultrasonic wave applying means 10 is installed on one side of the opening, and after ultrasonic waves are excited from one side, the posture of the hydrodynamic bearing 30 is reversed. Thus, the same cleaning accuracy can be obtained even when the same ultrasonic wave applying means 10 excites ultrasonic waves from the other side.

On the other hand, the cylinder length L of the bearing hole 33 of the dynamic pressure bearing 30
Is less than or equal to twice the inner diameter D of the bearing hole 33, that is, if L / D ≦ 2, the ultrasonic wave applying means 10 is installed only on one side of the opening of the dynamic pressure bearing 30, and Excitation of ultrasonic waves from the part side. In this case, since the cylinder length L is relatively short, a desired cleaning accuracy can be obtained only by exciting from one side of the opening.

After a series of washing steps as described above, the dynamic pressure bearing 30 is taken out of the holding plate 23. According to the present embodiment, as a result of measuring the number of foreign matters such as machining chips remaining on the surface of the cleaned dynamic pressure bearing 30, it was less than 300 pieces / cm ² in any of the dynamic pressure bearings 30. Therefore, the cleaning accuracy has been dramatically improved in a short time of cleaning as compared with the conventional cleaning method. Further, since the cleaning liquid 21 can exhibit sufficient detergency only by dissolving the surfactant in city water, the running cost can be reduced. Further, the structure of the entire cleaning device can be simplified, and the cleaning process can be semi-automated, so that the productivity is improved.

Next, another embodiment of the method of cleaning a dynamic pressure bearing according to the present invention will be described. FIG. 3 is a plan view schematically showing a cleaning device, and FIG. 4 is an enlarged side view of a main part of an ultrasonic wave applying means 60 used in the cleaning device. In FIG. 3, the holding plate 25 is provided with eight radially formed lanes on a mesh-like base portion, is installed in the cleaning tank 20 containing the cleaning liquid 21, and is rotatable around a shaft 26. Is configured. The eight lanes are counterclockwise from the supply unit IN in the first stage ST1, the second stage ST2, the third stage ST3, the fourth stage ST4,
It has a fifth stage ST5, a sixth stage ST6, and a discharge section, and each lane has a space for holding a plurality of hydrodynamic bearings. On the other hand, odd stage ST1,
Above ST3 and ST5 (upper side in the vertical direction of the paper), ultrasonic application means 60 as shown in FIG. 4 are respectively installed, and below even stages ST2, ST4 and ST6 (lower side in the vertical direction of the paper). Are provided with ultrasonic applying means 60, respectively.

The ultrasonic wave applying means 60 shown in FIG. 4 has almost the same structure as the ultrasonic wave applying means 10 shown in FIG.
The horn 64 attached to the tip of the cone 63 has a different shape. That is, the horn 64 is in the width direction (horizontal direction).
And at least the distal end surface 64 a has an area capable of confronting the plurality of dynamic pressure bearings 30 at one time. The ultrasonic wave applying means 60 installed above or below each of the stages ST1 to ST6 is a dynamic pressure bearing 3
It is closely opposed to 0 at an interval of 5 mm to 15 mm.

Now, a plurality of dynamic pressure bearings 30, for example, three, are supplied to the supply portion IN of the holding plate 25 shown in FIG.
At this time, the holding plate 25 is rotating counterclockwise around the shaft 26 at a low speed by a driving source (not shown). Therefore, the dynamic pressure bearing 3 supplied from the supply unit IN
0 eventually moves to the position of the first stage ST1.
Above the first stage ST1, the ultrasonic wave applying means 60
Is installed, each ultrasonic bearing 30 is irradiated with ultrasonic waves at the same time. Next, the first loaded dynamic pressure bearing 30
Is moved to the position of the first stage ST1, a plurality of other dynamic pressure bearings 30 are supplied from the supply unit IN. afterwards,
With the rotation of the holding plate 25, the first loaded dynamic pressure bearing 30 reaches the position of the second stage ST2, and the second loaded dynamic pressure bearing 30 moves to the position of the first stage ST1. Ultrasonic waves are applied to the dynamic pressure bearing 30 of ST2 from the ultrasonic wave applying means 60 installed below the dynamic pressure bearing 30. The ultrasonic wave applying means 60 installed above the dynamic pressure bearing 30 of the first stage ST1 is installed above the dynamic pressure bearing 30. Is irradiated with ultrasonic waves. At this time, since the base portion is formed in a mesh shape, the dynamic pressure bearing 30 of the second stage ST2 receives the ultrasonic waves from the lower ultrasonic wave applying means 60 without any trouble.
In addition, the dynamic pressure bearing 30 of the second stage ST2 is already in the first stage ST2.
Since the ultrasonic waves are irradiated from above on the stage ST1, the ultrasonic waves are received from both sides of the opening of the bearing hole 33 at this time.

As described above, with respect to the lane which has moved to the position of the supply unit IN with the rotation of the holding plate 25,
The dynamic pressure bearings 30 are sequentially supplied. Here, paying attention to the dynamic pressure bearing 30 that is initially supplied, in the third stage ST3, ultrasonic waves are again irradiated from above after the first stage ST1. Next, the fourth stage ST4 receives the ultrasonic wave again from below, and the fifth stage ST5 receives the third ultrasonic wave from above. In addition, the sixth stage ST
In FIG. 6, the third ultrasonic wave from below is received, and then the dynamic pressure bearing 30 reaching the discharge portion OUT is
5

According to the above-described cleaning method, since ultrasonic waves are applied to the dynamic pressure bearing 30 a plurality of times from both sides in the opening direction, foreign substances adhering to the dynamic pressure bearing 30 can be removed with high precision. It can be removed in a short time. In addition,
The number of lanes provided on the holding plate 25 is not limited to the above-described embodiment, and may be configured to an arbitrary number. Further, the embodiment using the ultrasonic applying means 60 having the horn 64 of a size capable of facing the plurality of dynamic pressure bearings 30 has been described, but cleaning is performed using the ultrasonic applying means 10 shown in FIG. You may. In this case, by installing the ultrasonic wave applying means 10 so as to be slidable in the radial direction of the holding plate 25, it is possible to irradiate all the inputted dynamic pressure bearings 30 with ultrasonic waves.

Next, an embodiment of the invention according to claim 5 will be described with reference to FIG. The ultrasonic wave applying means 70 shown in FIG. 5 has the same basic structure as the ultrasonic wave applying means 10 of FIG. The ultrasonic wave applying means 70 includes a vibrator 72 connected to an ultrasonic oscillator 71, a cone 73 for amplifying vibration energy generated by the vibrator 72, that is, ultrasonic vibration, and a horn 74 coupled to the cone 73. Have been. Of these, the horn 74 integrally has a distal end portion 74a having an outer diameter that can be inserted into the bearing hole 33 of the dynamic pressure bearing 30 as the body to be cleaned. Further, the ultrasonic wave applying means 70
Is fixed via a flange 73a to a support table 28 provided above the cleaning tank 20. The support 28 is
It is held movably up and down by urging means 29 such as a coil spring. On the other hand, a bearing holder 27 is provided at the bottom of the washing tank 20, and when the dynamic pressure bearing 30 is disposed in the holder 27 a, the bearing hole 33 of the dynamic pressure bearing 30 is intruded by the tip 74 a of the horn 74. The positional relationship between the ultrasonic wave applying means 70 and the bearing holder 27 is set in advance such that the position is allowed.

When the ultrasonic oscillator 71 of the ultrasonic wave applying means 70 is activated, the ultrasonic vibration amplified by the cone 73 is transmitted to the horn 74. Then, when the ultrasonic wave applying means 70 is lowered toward the cleaning liquid 21 against the urging force of the urging means 29, the front end portion 74a reaches the cleaning liquid 21 and the ultrasonic vibration is excited. Further, the ultrasonic wave applying means 70
Is lowered, the tip end portion 74 a enters the inside of the bearing hole 33, and the ultrasonic vibration is propagated to the inner peripheral surface of the bearing hole 33. At this time, the clearance between the inner peripheral surface of the bearing hole 33 and the outer peripheral surface of the distal end portion 74a becomes 200 μm to several millimeters, and the ultrasonic wave is directly applied to the dynamic pressure generating groove formed on the inner peripheral surface of the bearing hole 33. Vibration is propagated. Insert the tip 74a into the bearing hole 3
A sufficient cleaning effect can be obtained even if the time of infiltration into the inside of 3 is short. Then, after the excitation is continued for a predetermined time, the ultrasonic pressure applying means 70 is raised by using the urging force of the urging means 29, and the body to be cleaned is replaced. Cleaning of the grooves with extremely high precision is efficiently performed.

Although the embodiments of the present invention made by the inventor have been specifically described above, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say.

For example, in the embodiment shown in FIG.
Although the holding plate 23 is a flat plate, the dynamic pressure bearing 3
If the opening direction of 0 can be maintained in a substantially vertical direction,
It may be hook-shaped or mesh-shaped. Also, instead of moving the holding plate 23 in the horizontal direction as in the embodiment shown in FIG. 1, the excitation may be performed while moving the ultrasonic wave applying means 10 in the horizontal direction.
That is, by moving the dynamic pressure bearing 30 and the ultrasonic wave applying means 10 relatively in the horizontal direction, the ultrasonic wave is not transmitted from the specific direction to the dynamic pressure bearing 30 and the entire surface of the dynamic pressure bearing 30 is Can be washed uniformly with high precision.

[0040]

As described above, according to the cleaning method according to the first aspect of the present invention, the end face of the dynamic pressure bearing immersed in the cleaning liquid so that the opening direction is substantially vertical is provided. Since ultrasonic cleaning is performed with the sound wave applying means separated from each other by 15 mm or less, ultrasonic vibration is directly propagated to the inner peripheral surface of the dynamic pressure bearing with a substantially uniform size. Therefore, the inner peripheral surface of the bearing having the dynamic pressure generating groove can be cleaned well.

According to the second aspect of the present invention, since the cleaning is performed while the dynamic pressure bearing or the ultrasonic wave applying means is relatively moved in the horizontal direction, the position between the dynamic pressure bearing and the ultrasonic wave applying means is improved. Excited while the relationship changes relatively. As a result, the entire surface of the dynamic pressure bearing can be washed with high accuracy without transmitting ultrasonic waves from a specific direction to the dynamic pressure bearing.

According to the third aspect of the present invention, when the cylinder length of the dynamic pressure bearing is not more than twice the inner diameter, the ultrasonic wave applying means is brought into close proximity from one side of the opening of the dynamic pressure bearing. By exciting the particles, the foreign substances attached to the dynamic pressure generating grooves can be washed with high precision. Therefore, it is possible to perform high-precision cleaning with the minimum necessary number of ultrasonic wave applying means, and it is possible to suppress a rise in cleaning equipment. On the other hand, when the cylinder length of the dynamic pressure bearing is
In the case of more than double, the ultrasonic wave may not be transmitted to the inside of the bearing hole with an equal size. Dirt adhering to the pressure generating groove can be reliably washed.

Further, by adding a surfactant or a detergent having dissolving and dispersing power to the cleaning liquid as in the invention according to claim 4, the interfacial tension of the cleaning liquid is reduced, so that an extremely shallow fluid is formed. The cleaning liquid reliably reaches the bottom of the pressure generating groove. Accordingly, the dynamic pressure generating groove can be cleaned with extremely high precision by the excited cleaning liquid.

According to the fifth aspect of the present invention, since the horn is excited with the horn inserted into the bearing hole of the dynamic pressure bearing, the horn is also extended into the bearing hole of the dynamic pressure bearing where ultrasonic waves are relatively difficult to propagate. Propagation is ensured, and the dynamic pressure generating groove can be cleaned with extremely high precision.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an ultrasonic cleaning apparatus used for a cleaning method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a dynamic pressure bearing which is a member to be cleaned in the embodiment of the present invention.

FIG. 3 is a plan view illustrating an ultrasonic cleaning apparatus used in a cleaning method according to another embodiment of the present invention.

FIG. 4 is an enlarged view of a main part showing an ultrasonic wave applying means used in a cleaning method according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating an ultrasonic cleaning apparatus used in a cleaning method according to still another embodiment of the present invention.

FIG. 6 is an explanatory diagram relating to a conventional cleaning method.

[Explanation of symbols]

 10, 10 ', 60, 70 Ultrasonic wave applying means 14, 64, 74 Horn 20 Cleaning tank 21 Cleaning liquid 23 Support plate 27 Holder 30 Dynamic bearing 31a Dynamic pressure generating groove 33 Bearing hole

Claims (5)

[Claims] 1. A dynamic pressure for immersing a cylindrical dynamic pressure bearing having a dynamic pressure generating groove in a cleaning liquid contained in a cleaning tank and immersing an ultrasonic wave applying means in the cleaning liquid to clean the dynamic pressure bearing. A method of cleaning a bearing, wherein the dynamic pressure bearing is immersed in the cleaning liquid such that an opening direction of the cylindrical dynamic pressure bearing is substantially vertical, and the ultrasonic wave applying means is an end face of the dynamic pressure bearing. Cleaning the dynamic pressure bearing by transmitting ultrasonic waves generated by the ultrasonic wave applying means to the dynamic pressure bearing in a state of being separated by 15 mm or less from the dynamic pressure bearing. 2. The method for cleaning a dynamic pressure bearing according to claim 1, wherein the cleaning is performed while relatively moving the dynamic pressure bearing or the ultrasonic wave applying means in a horizontal direction. 3. When the length of the cylinder of the dynamic pressure bearing is not more than twice the inner diameter, the ultrasonic wave applying means is closely opposed from one side of the opening of the dynamic pressure bearing, and the cylinder of the dynamic pressure bearing is closed. 3. The method for cleaning a dynamic pressure bearing according to claim 1, wherein when the length is more than twice as large as the inner diameter, the ultrasonic wave applying means is closely opposed from both sides of the opening of the dynamic pressure bearing. . 4. The method for cleaning a dynamic pressure bearing according to claim 1, wherein a surfactant or a detergent having dissolving and dispersing power is added to the cleaning liquid. 5. A dynamic pressure for immersing a cylindrical dynamic pressure bearing having a dynamic pressure generation groove in a cleaning liquid contained in a cleaning tank and immersing an ultrasonic wave applying means in the cleaning liquid to clean the dynamic pressure bearing. A method for cleaning a bearing, wherein a horn that can be inserted into a bearing hole of the dynamic pressure bearing is provided in the ultrasonic wave applying means, and when the horn is moved in one direction, the horn is inserted into a bearing hole of the dynamic pressure bearing. A bearing holder that holds the dynamic pressure bearing at a position where the horn can be inserted is arranged in the cleaning tank, and after the dynamic pressure bearing is immersed in the cleaning liquid, the horn is inserted into the bearing hole. A method of cleaning a dynamic pressure bearing, comprising transmitting ultrasonic waves generated by the ultrasonic wave applying means to the dynamic pressure bearing for cleaning.