JP3229955B2 - Oil film thickness measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The oil film thickness measuring apparatus of the present invention measures the oil film retention performance of lubricating oil used in an air conditioner for automobiles or compressors (compressors) constituting various refrigerators. Used to measure in a simulated environment inside the machine.

[0002]

2. Description of the Related Art A compressor is incorporated in an air conditioner for a vehicle to compress a refrigerant gas such as freon.
As a compressor incorporated in an air conditioner for automobiles,
For example, a swash plate type (wobble type) compressor has been widely used. This swash plate type compressor includes a rotating shaft provided with a swash plate and pistons disposed on both end surfaces of the swash plate, and reciprocates the piston through the swash plate with the rotation of the rotating shaft, thereby causing the refrigerant gas to flow. Compress.

[0003] The swash plate and the piston are always in sliding contact with each other via a ball. The contact surface pressure at the sliding contact portion is high, and as it is, remarkable wear occurs at the sliding contact portion. Therefore, lubricating oil is supplied to the sliding contact portion to prevent the abrasion from occurring.

[0004] Since there are various types of lubricating oils, the lubricating oil is appropriately selected according to the material of the ball and the like. In this selection work, the oil film holding performance of the lubricating oil is measured to select the optimal lubricating oil. I do it.

[0005]

The measurement of the oil film retention performance of the lubricating oil described above has conventionally been performed in the atmosphere using a general lubrication performance tester or the like. However, since the lubricating oil circulates through the refrigerant circuit together with the refrigerant gas,
In this lubricating oil, the refrigerant gas sent into the compressor is in a state of being dissolved. Therefore, in the conventional oil film holding performance test of the lubricating oil, the decrease in the viscosity of the lubricating oil due to the dissolution of the refrigerant and the influence of the atmosphere of the refrigerant itself have not been considered. As a result, there has been a problem that the conventional evaluation does not sufficiently correspond to the actual demand of the compressor.

[0006] The oil film thickness measuring apparatus of the present invention, when conducting an oil film retention performance test of lubricating oil, takes into account the effect of refrigerant gas as well as the actual operating conditions of the compressor, and is equivalent to the actual compressor interior. In this environment, an oil film retention performance test of the lubricating oil can be performed in this environment.

[0007]

An oil film thickness measuring apparatus according to the present invention comprises a pressure vessel which is hermetically closed by closing an upper end opening by a lid, and a closed space in the pressure vessel, and one end of a shaft. A steel ball rotatably housed in a supported and fixed state,
A refrigerant supply port capable of supplying a refrigerant gas into the enclosed space from outside the pressure vessel, a driving unit for rotating the shaft, and a load applying unit for applying a load to the steel balls in the enclosed space; Load measuring means for measuring the load applied by the load applying means, and an optical measuring means for measuring the oil film thickness of the steel ball surface by a Newton ring generated at the contact portion between the steel ball and the load applying means I have. The driving unit includes a motor that rotates an outer cylinder that covers the outer peripheral surface of the other end of the shaft, a driving magnet fixed to the inner peripheral surface of the outer cylinder, and an outer peripheral surface of the other end of the shaft. And a magnet coupling composed of a driven magnet fixed at a position facing the driving magnet. In addition, the load applying means supports a glass plate that comes into contact with the steel ball, a holder that holds the glass plate, one end of each of the holders at both ends in the vertical direction of a base end of the holder, and the other end of the holder. A pair of first leaf springs fixed to both ends in the vertical direction of the piece and parallel to each other, one end of each of the first leaf springs is fixed to the pressure vessel, and the other end is connected to the middle of the support piece in the vertical direction. And a pair of second leaf springs fixed to each other and parallel to each other, and a pressing rod capable of pressing the support piece. The load measuring means is a pair of strain gauges attached to the pair of first leaf springs. Further, the optical measurement means is an interferometer in which a part of the lid facing a contact part between the steel ball and the glass plate is a glass part, and the glass part is a part of an optical path of measurement light.

[0008]

The oil film thickness measuring apparatus of the present invention configured as described above can perform an oil film holding performance test of a lubricating oil by setting the inside of a closed space to the same conditions as an actual compressor. Therefore, the evaluation of the oil film holding performance of the lubricating oil obtained using the oil film thickness measuring device of the present invention sufficiently satisfies the requirements of the actual compressor.

[0009]

1 to 7 show an embodiment of an oil film thickness measuring apparatus according to the present invention. The pressure vessel 2 is supported and fixed on one end (the right end in FIG. 6) of the base 1. This pressure vessel 2
Is openable and closable by a lid 4, and when closed, the pressure vessel 2 is in a sealed state. A through hole 36 is formed in the center of the lid 4, and the through hole 36 is closed by the glass plate 5. The glass plate 5 forms a glass part. 6 is a refrigerant gas supply port, and 38 is a lubricating oil supply port. At one end of the pressure vessel 2 (the right end in FIG. 6), a first side hole 7 for installing a load applying means described later is provided.
Are formed. The first side hole 7 is air-tightly closed by installing the cover cylinder 8 after installing the load applying means. On the other hand, a second side hole 10 for inserting a shaft 9 described below is provided on the other end side (the left end side in FIG. 6) of the pressure vessel 2.

One end of the shaft 9 (right end in FIGS. 1 and 2)
Is inserted through the second side hole 10 into the pressure vessel 2 while being supported by bearings 15, 15. One end of the shaft 9 is inserted into a through hole 12 formed in the steel ball 11, and the steel ball 11 is bolted between a locking flange 13 provided on the shaft 9 and a locking piece 14. Are screwed together to fix and fix. A cover cylinder 17 is provided on the outer periphery of the other side (left side in FIGS. 1 and 2) of the shaft 9 protruding outside the pressure vessel 2 to keep the portion airtight.

The other end of the shaft 9 is connected to one end of a connecting shaft 18. The other end of the cover tube 17 is connected to one end of a connection tube 19 that covers the outer periphery of the connection shaft 18. Further, the other end of the connecting cylinder 19 is an inner cylinder 20 that covers the outer periphery of the connecting shaft 18 on the other side.
Are connected at one end. An outer cylinder 21 is provided on the outer peripheral side of the inner cylinder 20. A drive-side permanent magnet 22 is provided inside the outer tube 21, and a driven-side permanent magnet 23 is provided at a position facing the drive-side permanent magnet 2 via the inner tube 20 at the other end of the connection shaft 18. By providing them, a conventionally known magnet coupling 34 is configured.

A motor 24 is provided at the other end (the left end in FIG. 6) of the base 1, and the rotation of the motor 24 can be transmitted to the outer cylinder 21 via a belt 37. Therefore, when the motor 24 is energized, the shaft 9 rotates via the magnet coupling 34, and the steel ball 11 fixed to one end of the shaft 9 rotates. That is, the motor 24 and the magnet coupling 34 constitute a driving device.

FIG. 5 shows the first side hole 7 of the pressure vessel 2.
The load applying means shown in (1) is installed. This load applying means is a glass plate 31 (FIGS. 1 and 2) that comes into contact with the steel ball 11.
A holder 28 for holding the glass plate 31 and one end (the left end in FIG. 5) of the holder 28 are fixed to the upper and lower end surfaces of the base end of the holder 28, and the other end (the right end in FIG. 5). A pair of fixed first leaf springs 25, 25 and one end (the left end in FIG. 5) of a pair of parallel first leaf springs 25 are respectively formed on upper and lower end surfaces of the support piece 26 formed in a laterally convex shape. Figure 1
2 is fixed to the upper and lower surfaces of a fixing plate 35 provided in the front and back directions, and the other end (the right end in FIG. 5) is
A pair of parallel second leaf springs 27, 27 fixed to the convex portion of the support piece 26, and a pressing member 30 capable of pressing the support piece 26 are provided.

The second leaf springs 27, 27
8 has a function of displacing the glass plate 31 held in the up and down direction while maintaining the horizontal state. Strain gauges 29, 29 serving as load measuring means are attached to side surfaces of the first leaf springs 25, 25, and the magnitude of the load applied by the pressing member 30 is adjusted by the first leaf springs 25, 25. It can be calculated by measuring the amount of distortion of 25. In the present invention, since the load measuring means can be provided inside the pressure vessel 2, it is not necessary to consider the influence of the friction loss of the sealing material as in the case where the load measuring means is provided outside the pressure vessel 2, and the The measurement is accurate. In order to improve the accuracy of the load measurement, the glass plate 31 is positioned as perpendicular to the circumference of the steel ball 11 as possible at the contact portion with the steel ball 11. The pressing member 30 is screwed into a screw hole 38 provided in the pressure vessel 2,
By rotating, it is displaced up and down. The support member 26 is pressed by displacing the pressing member 30 downward.

Therefore, if the pressing member 30 is appropriately lowered and a desired amount of load is applied to the support piece 26, the first and second leaf springs 25 and 27 will respond to the amount of lowering of the pressing member 30. The holder 28 is displaced. At the same time, the amount of deflection of the second leaf springs 27
The pair of strain gauges 29, 29 detect. Then, the deflection amount detected by the strain gauges 29, 29 is converted into a load by a controller (not shown).

The glass plate 31 held by the holder 28
When the steel ball 11 comes into contact with the steel ball 11, a Newton ring is formed at the contact portion. This Newton ring is the steel ball 1
Since the diameter changes according to the thickness of the oil film formed on one surface, the oil film thickness can be measured by measuring the diameter of the Newton ring. As the optical measuring means, a conventionally known interferometer using the glass plate 5 of the lid 4 as a part of the optical path of the measuring light is used.

When the oil film holding performance test of the lubricating oil is performed using the oil film thickness measuring apparatus of the present invention configured as described above, the test is performed as follows. By operating the motor 24, the shaft 9 is rotated via the belt 37 and the magnetic coupling 34. At this time, the refrigerant gas is supplied from the refrigerant gas supply port 6 and the lubricating oil is supplied from the lubricating oil supply port 38.
A gear-shaped concave / convex portion 32 is provided on the outer peripheral surface of the outer cylinder 21, and a rotational speed detecting device is constituted by the concave / convex portion 32 and a sensor (not shown). The rotation speed of the shaft 9 can be detected by the rotation speed detection device.

The steel ball 11 rotates with the rotation of the shaft 9. A glass plate 31 constituting the load applying means is located above the steel ball 11. With the displacement of the pressing member 30, the glass plate 31 is raised and lowered in a horizontal state, and The steel balls 11 are brought into contact with each other to apply a load.

At the contact portion between the glass plate 31 and the steel ball 11,
A Newton ring having a diameter corresponding to the thickness of the oil film formed on the surface of the steel ball 11 is generated. In the measuring apparatus according to the present invention, the diameter of the Newton ring can be freely measured by a conventionally known interference microscope 33 using, for example, a two-beam interferometer. The oil film thickness can be calculated based on the diameter measured by the interference microscope 33.

In particular, in the measuring apparatus of the present invention, the environment inside the pressure vessel 2 can be made substantially equal to that of an actual compressor. That is, in a compressor for air conditioning, lubricating oil is supplied together with refrigerant gas such as freon, and since this lubricating oil circulates with the refrigerant in the refrigerant circuit, the lubricating oil is in a state in which the refrigerant is dissolved. I have. In the present invention, by making the refrigerant gas freely supplied into the pressure vessel 2, the atmosphere environment of the closed space can be configured in the same manner as the actual machine. Furthermore, by circulating a circulating water coil around the outer circumference of the pressure vessel 2 and circulating water in the coil, the temperature of the lubricating oil in the pressure vessel 2 can be adjusted to be equal to that of the actual machine.

Therefore, in the oil film thickness measuring apparatus of the present invention, it is possible to test the oil film holding performance of the lubricating oil under substantially the same environment as the actual compressor. As a result, the most suitable lubricating oil for extending the life of the bearing can be selected, which contributes to the long-term stable operation of the compressor for the refrigerator.

[0022]

The apparatus for measuring the oil film thickness of a lubricating oil for compression according to the present invention is constructed and operated as described above. Therefore, the oil film retaining performance of the lubricating oil is tested under substantially the same environment as that of an actual compressor. Can do things. Therefore, it is possible to select the most suitable lubricating oil for the compressor to be used. Therefore, this contributes to a longer life of the rolling bearing and a stable operation of the compressor for a long period of time.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is an enlarged view of a portion C in FIG. 2;

FIG. 5 is a perspective view showing a load applying unit.

FIG. 6 is a plan view showing the appearance.

FIG. 7 is a side view as viewed from the right in FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 base 2 pressure vessel 3 upper end opening 4 lid 5 glass plate 6 refrigerant gas supply port 7 first side hole 8 covering cylinder 9 shaft 10 second side hole 11 steel ball 12 through hole 13 locking flange 14 Locking piece 15 Rolling bearing 16 Bolt 17 Covering cylinder 18 Connecting shaft 19 Connecting cylinder 20 Inner cylinder 21 Outer cylinder 22 Drive-side permanent magnet 23 Follower-side permanent magnet 24 Motor 25 First leaf spring 26 Support piece 27 Second leaf spring 28 Holder 29 Strain gauge 30 Pressing member 31 Glass plate 32 Irregularity part 33 Interferometric microscope 34 Magnet coupling 35 Fixing plate 36 Through hole 37 Belt 38 Lubricating oil supply port

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-59548 (JP, A) Japanese Utility Model Application Sho 60-92201 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30

Claims (1)

(57) [Claims] 1. A pressure vessel sealed by closing an upper end opening with a lid, and a steel ball rotatably housed in a sealed space inside the pressure vessel while being supported and fixed to one end of a shaft. A refrigerant supply port capable of supplying a refrigerant gas from outside the pressure vessel into the closed space, a driving unit for rotating the shaft, and a load applying unit for applying a load to the steel ball in the closed space. A load measuring means for measuring the load applied by the load applying means, and an optical measuring means for measuring the oil film thickness of the steel ball surface by a Newton ring generated at a contact portion between the steel ball and the load applying means. The driving unit includes a motor that rotates an outer cylinder that covers the outer peripheral surface of the other end of the shaft, a driving magnet fixed to the inner peripheral surface of the outer cylinder, and an outer peripheral surface of the other end of the shaft. Is the driven magnet fixed at a position facing the driving magnet? The load applying means comprises a glass plate that comes into contact with the steel ball, a holder that holds the glass plate, and one end of each of the holders at the upper and lower ends of the base end of the holder. The other end of each is fixed to the upper and lower ends of the support piece, respectively, a pair of first leaf springs parallel to each other, and each end is fixed to the portion of the pressure vessel, each other end, A pair of second leaf springs, which are fixed to an intermediate portion in the vertical direction of the support piece and are parallel to each other, and a pressing rod capable of pressing the support piece, the load measuring means includes:
A pair of strain gauges attached to a pair of first leaf springs, wherein the optical measuring means has a part of the lid facing a contact part between the steel ball and the glass plate as a glass part; An oil film thickness measurement device that is an interferometer that uses a glass part as a part of the optical path of the measurement light.