JPS6371591A - Bearing structure of rotary compressor - Google Patents

Abstract

PURPOSE:To prevent degradation of abrasion resistance and occurrence of burning phenomenon due to local increase of bearing surface pressure, by forming a thin film layer of hard material at least at the inner circumferential face section corresponding to the suction side of a compressor in the bearing section. CONSTITUTION:Opposite end sections 9b, 9c of a crankshaft formed with an eccentric shaft section 9a are supported by tubular bearing sections 5a, 6a formed on front and rear heads 5, 6. A thin film layer 20 of hard material mainly composed of ceramics such as TiN, SiN, SiC, etc. having the thickness of about 5mu is formed through surface treatment such as deposition at the inner circumferential section of the bearing sections 5a, 6a corresponding to the suction side. The section formed with the thin film 20 is subjected to compresive reaction so as to displace the crankshaft 9 thus increasing the surface pressure, but since the thin film layer 20 has high hardness, degradation of abrasion resistance or occurrence of burning phenomenon can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bearing structure for supporting a crankshaft in a rotary compressor equipped with an eccentric shaft portion.

(Prior Art) Conventionally, the crankshaft of a rotary compressor has an eccentric shaft portion installed in a bore in a cylinder of a compression element, and
Both sides of the eccentric shaft in the axial direction are supported by bearings provided in the front head and the rear head, and the bearings include an oil supply pump provided at the end of the crankshaft and a fuel pump formed inside the shaft. Lubricating oil is supplied through the oil supply passage to provide lubrication.

(Problems to be Solved by the Invention) However, when the compressor configured as described above is operated by driving the crankshaft, a compression reaction force acts on the crankshaft, and the compression in the cylinder is reduced. Therefore, the surface pressure on the bearing section that supports the crankshaft increases, and even if lubricating oil is supplied to the bearing section, it is difficult to maintain a proper lubrication state. There was a problem in that uneven wear occurred in the bearing portion.

Therefore, in order to solve the above problems, a bearing metal is usually used in the bearing part to improve the wear resistance of the bearing part, but the bearing metal is used separately from the front head and rear head. Since it is necessary to form and press-fit the metal into the bearing portion, there is a problem that not only the number of parts increases, but also the number of machining steps for press-fitting increases, resulting in high costs.

An object of the present invention is to provide a bearing structure that can improve the wear resistance of a bearing portion and eliminate the seizure phenomenon without using a bearing metal.

(Means for Solving the Problems) In order to eliminate the uneven wear of the bearing portion described above, the present invention does not use a bearing metal, and as shown in FIGS. 1 and 2,
A thin film layer (20) made of a high hardness material mainly made of ceramics is deposited on the inner peripheral surface portion of the bearing portion (5aT e a ) corresponding to at least the suction side of the compressor by a surface treatment method such as vapor deposition. be.

(Function) Since the thin film layer (20) is formed on the above-described inner circumferential surface portion or the entire inner circumferential surface of the bearing portion (5al8a), when driving the crankshaft (9), Due to the compression reaction force, the crankshaft (9)
8 a) The surface pressure increases as it is pressed against
Even if the bearing part (
5a, 6a) will not wear unevenly, and the wear resistance can be improved, and the seizure phenomenon can be reliably eliminated.

(Example) The rotary compressor shown in Fig. 3 has a hermetic casing (
A compression element (2) is installed in the lower part of 1), and a motor (3) is installed in the upper part, and the compression element (2) is attached to the front head (2) above and below a cylinder (4) having a cylinder bore (4a) inside. 5) Connect the catcher head (6) and insert the eccentric shaft portion (9a) of the crankshaft (9) into the bore (4a).
and a roller (7) that fits into the eccentric shaft (9a), while the cylinder (4) is equipped with a blade (
8) is slidably held and the blade (8) is used to open the bore (4a) into a low pressure chamber (11) which opens the suction port (10) and a high pressure chamber (11) which opens the discharge port (12). 13)
It is divided into

Then, the front head (5) and the rear head (6)
) are respectively provided with bearing parts (5a) and (6a) for the cane,
The eccentric shaft portion (9) is attached to these bearing portions (5a) (6a).
The shaft portion (9) of the crankshaft (9) is located on both sides in the axial direction of a).
b) It supports (9c).

In Fig. 1, (14) is a discharge valve, (15) is a discharge muffler, (16) is a suction pipe, (17) is a fuel pump,
(18) is an oil sump at the bottom of the casing (1), and (19) is formed on the crankshaft (9), and the lubricating oil in the oil sump (18) is supplied through the oil supply pump (17). This is a oil supply passage that supplies oil to the sliding contact area.

Therefore, in the embodiment shown in FIGS. 1 to 3, the bearing portion (5a) (
A thin film layer (20) with a thickness of about 5μ made of a high-hardness material mainly composed of ceramics (Tin+Sin+SiC, etc.) is deposited on the inner peripheral surface portion corresponding to the suction side of 6a) using a surface treatment method such as vapor deposition. It is.

The bearing part (5a) forming the thin film layer (20)
The inner circumferential surface portion of (8a) receives a compressive reaction force during operation driven by the crankshaft (9), and the inner peripheral surface portion of the crankshaft (9)
is displaced and the surface pressure rises due to this displacement, and for the bearing part (5a), this part is on the opposite side of the oil groove (5b) provided in the bearing part (5a), and When partially formed on the inner circumferential surface portion, the thin film layer (20)
The inner surface of the bearing portion (5a) is elliptical.

Further, the thin film layer (20) may be formed not only partially as described above but also on the entire inner circumferential surface of the bearing portion (5a) (8a). In the case of forming it on the entire surface like this, even if the inner circumferential surface roughness of the bearing portion (5a) C6a) is reduced,
The surface roughness of each shaft portion (9) of the crankshaft (9) to be subjected to rubrite processing can be increased.
b) Together with (9C), the crankshaft (9) can be supported more smoothly.

Next, the operation of the compressor equipped with the bearing structure as described above will be explained.

When the crankshaft (9) is rotated by the drive of the motor (3), and the eccentric shaft portion (9a) and the roller (7) are rotated eccentrically, low pressure gas flows from the suction pipe (16) to the suction port (10).
The high pressure gas in the high pressure chamber (13) is drawn into the low pressure chamber (11) of the bore (4a) through the discharge port (12).
) is discharged from the discharge valve (14) to the discharge muffler (15).

At this time, the crankshaft (9) is connected to the high pressure chamber (13).
) is deflected to the suction side due to the reaction force of the compression action at Since the above-mentioned thin film layer (20) is attached to the inner circumferential surface, there is less wear even if the lubricated state is not maintained, improving the wear resistance and ensuring the seizure phenomenon. This can be resolved by

Furthermore, since the thin film layer (20) can be formed by a surface treatment method, it can be formed more easily than in the case of press-fitting the bearing metal, which is economically advantageous.

(Effects of the Invention) As described above, the present invention provides a method for forming a thin film layer (20) made of a highly hard material on the inner peripheral surface portion of the bearing portion (5a, 8a) corresponding to at least the suction side of the compressor. Since the crankshaft (9) is characterized by
) is deflected by the reaction force of the compression action, and even if the surface pressure increases, it can reduce wear, improve its wear resistance, and reliably eliminate the seizure phenomenon. ,
Furthermore, since there is no need to press-fit bearing metal, the number of parts can be reduced, and since the thin film layer (20) can be deposited and formed using a surface treatment method, the number of processing steps does not increase, and therefore, the cost increases. It is also possible to prevent this from happening.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a bearing structure showing an embodiment of the present invention;
FIG. 2 is a cross-sectional view, and FIG. 3 is a partial cross-sectional view of a compressor to which the bearing structure of the present invention is applied. (5a) (5b)...Bearing part (9)...
... Crankshaft (9a) ... Eccentric shaft part (20) ... Thin film layer 1st section

Claims (2)

[Claims] (1) A bearing structure for supporting a crankshaft (9) in a rotary compressor including an eccentric shaft portion (9a), the inner periphery of the bearing portion (5a, 6a) corresponding to at least the suction side of the compressor. A bearing structure for a rotary compressor, characterized in that a thin film layer (20) made of a highly hard material is adhered to a surface portion. (2) A thin film layer (20) made of a highly hard material is formed on the entire inner peripheral surface of the bearing portion (5a, 6a).
Bearing structure of rotary compressor described in section.