CN111486075B

CN111486075B - Compressor

Info

Publication number: CN111486075B
Application number: CN201910831161.8A
Authority: CN
Inventors: 川村勇贵; 山下智宽; 秋泽健裕; 永田修平
Original assignee: Hitachi Global Life Solutions Inc
Current assignee: Hitachi Global Life Solutions Inc
Priority date: 2019-01-28
Filing date: 2019-09-04
Publication date: 2022-07-26
Anticipated expiration: 2039-09-04
Also published as: JP7096633B2; JP2020118136A; CN111486075A

Abstract

The present invention provides a compressor with improved reliability. The compressor has: a crankshaft which is driven by a motor to rotate freely and has a cavity at the lower end side; a substantially cylindrical screw block, a lower end side of which is immersed in lubricating oil; a substantially cylindrical second member having a side circumference facing the side circumference of the spiral piece; and a spiral groove provided between the screw block and the other member, for extracting the lubricating oil by a relative movement between a side circumference of the screw block and a side circumference of the other member, wherein R defined by Japanese Industrial standards is a surface roughness of the side circumference of the other member _zJIs Is 25 μm or less.

Description

Compressor

Technical Field

The present invention relates to a compressor.

Background

As a hermetic compressor, a hermetic compressor is known which extracts lubricating oil by using a centrifugal force based on rotation of a crankshaft and an inertial force based on rotation of the crankshaft and viscosity of the lubricating oil. The "viscous oil supply mechanism" utilizing viscosity of patent document 1 is disposed below the cavity 160 of the main shaft portion 120 of the crankshaft 118, and performs extraction by relative rotational movement between the insertion portion 166 provided with the spiral groove 176 and the crankshaft 118 (paragraphs 0053 and 0056, fig. 2). The lower end side of the insertion portion 166 is held by the bracket 164.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012 and 180796

Disclosure of Invention

Problems to be solved by the invention

When the compressor is operated to stir up the lubricating oil, the lubricating oil flows between the cavity 160 and the spiral groove 176, and a force coaxial with the cavity 160 acts on the upper end side of the insertion portion 166. The holding force prevents the insertion portion 166 from coming into contact with the lower end side of the main shaft portion 120 of the shaft 118 (a portion surrounding the periphery of the cavity 160, the inner diameter surface of the main shaft portion 120), and it is considered that the mechanical holding is sufficiently ensured by the holder 164. Therefore, patent document 1 does not disclose any problem of contact between the insertion portion 166 and the main shaft portion 120 or any structure provided for the contact.

However, in recent years, a low power consumption of a household refrigerator or the like equipped with a hermetic compressor has been required, and therefore, the rotational speed of the hermetic compressor has been reduced. This tends to reduce the flow rate of the lubricating oil, i.e., the holding force. Then, it was found that the upper end of the insertion portion 166 was held less than the self weight of the insertion portion 166 and inclined, that is, the contact between the two was increasing.

Means for solving the problems

In view of the above, the present invention provides a compressor including:

a crankshaft which is rotatable by driving of a motor and has a cavity at a lower end side;

a substantially cylindrical screw block having a lower end side immersed in the lubricating oil;

a substantially cylindrical second member having a side circumference facing the side circumference of the screw block; and

a spiral groove provided between the spiral piece and the other member,

the lubricating oil is extracted by the relative movement of the side circumference of the screw block and the side circumference of the other member,

the surface roughness of the side periphery of the other member is R defined in the Japanese Industrial Standard _zJIS Is less than 25 μm.

Drawings

Fig. 1 is a longitudinal sectional view of a hermetic compressor of the embodiment.

Fig. 2 is a partial sectional view of the crankshaft and the screw block, where (a) is embodiment 1 and (b) is embodiment 2.

Fig. 3 is a partially enlarged view of fig. 2 (b).

In the figure:

1-a closed container, 1 a-an upper housing, 1 b-a lower housing, 2-a compression element, 3-a lubricating oil, 23-a frame, 23 a-a base portion, 23 b-a cylinder, 23 c-a radial bearing, 24-a piston, 25-a piston pin, 26-a balancer, 27-a crankshaft (an example of the other component), 27 a-a crank pin, 27 b-a flange portion, 27 c-a bore, 27 d-an upper communication hole, 27 e-a spiral groove, 27 f-a pin bore, 27 g-a pin communication hole, 27 h-a pin upper oil supply hole, 27 j-a lower oil supply hole, 27 k-an enlarged diameter portion, 28-a rod, 29-a thrust bearing, 30-a screw block, 30a blank hole, 31-a jig, 32-a fixing component (an example of the other component), 140-an electromotive element, 141-a rotor, 142-a stator.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. The various components of the present invention are not necessarily independent of each other, and for example, it is permissible that a certain component is constituted by a plurality of members, that a plurality of components are constituted by one member, that a part of a certain component overlaps with a part of another component, or the like.

Fig. 1 is a longitudinal sectional view of a hermetic compressor according to the present embodiment. Fig. 2 is a schematic sectional view illustrating the viscous oil supply mechanism of the hermetic compressor, where (a) is embodiment 1 and (b) is embodiment 2. The hermetic compressor is a so-called reciprocating compressor in which a piston or the like is disposed in a hermetic container 1.

(hermetic compressor)

The hermetic compressor includes a crankshaft 27 rotated by driving of a motor, a connecting rod 28 for converting the rotational motion of the crankshaft 27 into the reciprocating motion of the piston 24, and the piston 24 reciprocating in the cylinder 23b to compress a refrigerant. The lubricating oil stored in the lower portion of the closed casing 1 is pumped and supplied to the piston 24.

The motor has a rotor 141 and a stator 142. The rotor 141 is configured to include a rotor core formed by laminating electromagnetic steel plates, and is fixed to a lower portion of the crankshaft 27 by press fitting or the like.

The stator 142 is disposed on the outer periphery of the rotor 141, and includes: an iron core (not shown) including a cylindrical stator core and a plurality of slots formed in an inner periphery of the stator core; and a coil (not shown) wound around the core.

(oil supply based on the crankshaft 27, etc. and the screw block 30)

The crankshaft 27 has a substantially cylindrical hollow portion extending upward from a lower end. In embodiment 1, a hollow substantially cylindrical fixing member 32 is provided at the lower end of the hollow portion, and the lower end of the crankshaft 27 is press-fitted, and a substantially cylindrical screw block 30 is inserted into the fixing member 32. The lower end of the fixing member 32 is immersed in the lubricating oil 3. On the other hand, in embodiment 2, a substantially cylindrical screw block 30 is inserted into the lower end of the hollow portion of the crankshaft 27, and the lower end of the crankshaft 27 is immersed in the lubricating oil 3.

At least the lower end of the screw block 30 is immersed in the lubricating oil, and the side circumference is surrounded by the fixing member 32 (embodiment 1) or the crankshaft 27 (embodiment 2) from the lower end side to the upper end side. Here, a member having a portion surrounding the side periphery of the lower end of the screw block 30, that is, the fixed member 32 in embodiment 1 and the lower end of the crankshaft 27 in embodiment 2 is referred to as the other member.

The lower end side of the screw block 30 is fixed by a jig 31 so as not to rotate or to rotate at a low speed thereby even if the crankshaft 27 rotates. The jig 31 is used mainly by forming a hard wire or the like, and is inserted into a hole 30a provided in a lower portion of the screw block 30. The screw block 30 of each embodiment is rotatable around the central axis of the hole. Since the relative rotational movement between the screw block 30 and the other member causes the lubricant oil 3 to rise along the below-described spiral groove 30b, the rotation of the screw block 30 can be completely restricted by the jig 31.

A spiral groove 30b (first spiral groove) is formed in the outer peripheral surface of the spiral piece 30, and a spiral lubricant passage is formed between the spiral piece and at least the lower end inner surface of the other member. When the crankshaft 27 rotates, relative rotational motion occurs between the screw block 30 and the other member, and the lubricant oil 3 stored in the lower portion is pulled by the wall surface of the screw block 30 due to the viscous effect and rises in the spiral groove 30 b. It is known that the amount of lubricant oil rising in the spiral groove 30b is proportional to the rotation speed of the crankshaft 27. The spiral groove 30b may be disposed in the other member.

The lubricating oil rising in the spiral groove 30b moves from the oil supply hole 27j located midway in the spiral groove 30b or above the spiral groove 30b and communicating the inner circumferential side and the outer circumferential side of the crankshaft 27 to the outer circumferential surface side of the crankshaft 27 as in the respective embodiments. As illustrated in fig. 1, another spiral groove 27e (second spiral groove) is provided above the outer peripheral surface side of the crankshaft 27, and the lubricating oil further rises along the spiral groove 27e, flows from the pin communication hole 27g of the crankshaft 27 to the pin bore 27f, and rises above the crank pin 27a along the inner wall of the pin bore 27 f. Then, the lubricating oil flows into the pin portion upper oil supply hole 27h, passes through a balancer oil supply hole (not shown), and is splashed by centrifugal force to supply the oil to the piston 24.

(investigation of contact of the screw block 30 with other parts)

The screw block 30 is a member having a relatively high strength requirement, and can be manufactured by mixing a glass filler into a resin material, for example. Therefore, if the engine is operated in a state of being kept in contact with the other member (the inner peripheral surface of the fixed member 32 in embodiment 1 or the inner peripheral surface on the lower end side of the crankshaft 27 in embodiment 2) forming the lubricating oil passage, there is a problem of wear.

Therefore, of the other components forming the lubricant passage, at least the surface 200 on the side in contact with the screw block 30 has the surface roughness R _zJIS Is set to be 25 μm or less. The surface roughness was measured in accordance with a ten-point average roughness of JISB 0031 (1994).

(examination of the other member 32, 27)

As the other component forming the lubricant passage together with the screw block 30, a fixing member 32 as another component provided at the lower end of the crankshaft 27 and the lower end of the crankshaft 27 itself may be considered as disclosed in

embodiments

1 and 2. As in embodiment 1 shown in fig. 2 (a), when the fixing member 32 is fixed to the lower portion of the crankshaft 27, press fitting is generally employed from the viewpoint of workability. However, when the fixing member 32 is press-fitted and fixed to the crankshaft 27, which is generally made of cast iron, the crankshaft 27 and the fixing member 32 are deformed to some extent. Accordingly, the roundness of the inner side of the fixed member 32 is deteriorated, and a gap between the fixed member 32 and the fixed member is unbalanced, which may reduce the oil supply capability of the viscous oil supply mechanism. Therefore, as in embodiment 2, it is preferable that the lower end of the crankshaft 27 is immersed in the lubricating oil 3 without providing the fixing member 32.

Here, patent document 1 describes with reference to japanese unexamined patent publication No. 2002-519589 as a background art, and discloses fig. 6 (paragraphs 0006 and 0007) as a diagram showing japanese unexamined patent publication No. 2002-519589. Accordingly, it can be seen that the main shaft portion 20 is immersed in the lubricant oil to the extended lower end, but if japanese unexamined patent publication No. 2002-519589 is confirmed, the extension portion 40 is press-fitted into the lower end of the shaft 20 (paragraph 0022, fig. 2). Accordingly, fig. 6 of patent document 1 is a schematic diagram.

Fig. 3 is a partially enlarged view of fig. 2 (b) of embodiment 2. When the motor is operated at a low speed, the amount of lubricating oil is small, so that the holding force is hard to act, and the screw block 30 may be inclined. In this case, the upper end of the screw block 30 is in point contact with the crankshaft 27, and therefore, particularly, there is a high possibility of breakage. Therefore, in embodiment 2, when the screw block 30 is inclined on the inner surface of the crankshaft 27, the enlarged diameter portion 27k is disposed in a region that comes into contact with the crankshaft 27. The diameter-enlarged portion 27k is a portion tapered so that the diameter thereof is smaller at the lower side and larger at the upper side.

The position of the diameter-enlarged portion 27k is near the upper end of the screw block 30 when the screw block 30 and the crankshaft 27 are not in contact with each other. More specifically, the screw block 30 is provided slightly below the height of the upper end portion thereof (for example, if the screw block is a hermetic compressor for a refrigerator, the screw block is provided at a height from a position 5mm below the upper end to the upper end). This makes it easy for the screw block 30 to come into surface contact with the crankshaft 27 even if it is inclined, and therefore the risk of damage can be reduced. Of course, in embodiment 1, if the fixing member 32 has a considerable thickness, the enlarged diameter portion can be disposed.

Claims

1. A compressor, having:

a spiral groove provided between the spiral piece and the other member,

the compressor is characterized in that the lubricating oil is extracted by the relative movement of the side circumference of the screw block and the side circumference of the other component,

the surface roughness of the side periphery of the other member is R defined by the Japanese Industrial Standard _zJIS Is less than 25 mu m in the weight ratio,

a diameter-expanded portion provided at a height in the vicinity of the upper end of the screw block on a side circumference of the other member, the diameter-expanded portion being provided at a height slightly lower than the upper end of the screw block,

the diameter-enlarged portion is a portion tapered so as to have a smaller diameter at the lower side and a larger diameter at the upper side.

2. The compressor of claim 1,

the other member is the crankshaft.