EP1876357B1

EP1876357B1 - Oil supply structure of scroll compressor

Info

Publication number: EP1876357B1
Application number: EP20060013933
Authority: EP
Inventors: Cheol-Hwan Kim; Dong-Koo Shin; Yang-Hee Cho
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2006-07-05
Filing date: 2006-07-05
Publication date: 2011-01-26
Anticipated expiration: 2026-07-05
Also published as: EP1876357A1; DE602006019847D1

Description

The present invention relates to an oil supply structure of a scroll compressor as defined in the preamble of claim 1. Such a structure is known eg from JP-A-2003035286 . The invention more particularly, relates to an oil supply structure of a scroll compressor for preventing a slender hole of an oil supply screw from being clogged with sludge, the oil supply screw being provided between a backpressure space, which is defined between an orbiting scroll and a main frame, and a space which is defined between a fixed scroll and the main frame, and adapted to supply oil from the backpressure space into the space.
A general scroll compressor, as shown in FIG. 1, includes a main frame 2 and sub frame 3 mounted in a shell 1 at upper and lower locations of the shell 1, a stator 4 press-fitted in the shell 1 between the main frame 2 and the sub frame 3, and a rotor 5 disposed in the stator 4 and adapted to rotate by power applied thereto.
A vertical crank shaft 6 is fixedly inserted into the center of the rotor 5 such that opposite ends thereof are rotatably supported by the main frame 2 and sub frame 3, respectively. Then, the vertical crank shaft 6 is rotated along with the rotor 5.
The scroll compressor further includes a compression unit including an orbiting scroll 7 disposed on an upper end surface of the main frame 2, and a fixed scroll 8 located over the orbiting scroll 7 to be secured to an inner periphery of the shell 1. The orbiting scroll 7 has a lower portion coupled to the crank shaft 6 and an upper portion forming an involute orbiting wrap 7a. The fixed scroll 8 has a fixed wrap 8a configured to be engaged with the orbiting wrap 7a in such a manner that a compression chamber 21 is defined between the fixed wrap 8a and the orbiting wrap 7a. With this configuration, while the orbiting scroll 7 performs an orbiting rotation by rotation of the crank shaft 6, refrigerant gas introduced into the compression chamber 21 can be compressed.
A structure for coupling the crank shaft 6 with the orbiting scroll 7 includes a hollow boss 7b, which protrudes downward from the center of a lower portion of the orbiting scroll 7, and a crank pin 10 which protrudes upward from the center of an upper end surface of the crank shaft 6 by a predetermined distance to be inserted into the hollow boss 7b. A bearing 11 is forcibly press-fitted in the boss 7b, and an eccentric bush 12 is rotatably coupled around the crank pin 10.
In addition, an Oldham's ring 9 serving as anti-rotation device is interposed between the main frame 2 and the orbiting scroll 7. An oil supply path 6a is vertically defined in the crank shaft 6 throughout the overall length of the crank shaft 6. A pair of upper and lower balancing weights 13 and 14 are arranged above and below the rotor 5, respectively, to prevent unbalanced rotation of the crank shaft 6 that may be caused by the crank pin 10.
If high-pressure refrigerant gas compressed in the above described compression unit is discharged through an outlet 17 of the fixed scroll 8, the high-pressure refrigerant gas imparts a direct shock to a top cap 1a constituting an upper end of the shell 1, thus causing generation of noise. Accordingly, to reduce the noise, a muffler 22 is mounted above the fixed scroll 8. The muffler 22, as shown in FIG. 2, takes the form of a cover.
In addition to this noise reduction function, the muffler 22 has a function of isolating a suction pressure from a discharge pressure, namely, a low-pressure portion from a high pressure portion when the scroll compressor has a high-pressure structure wherein a lower region of the compressor is filled with the high-pressure refrigerant gas discharged from the compression unit. The fixed scroll 8 has guidance paths 23 to guide the compressed refrigerant gas in the muffler 22 into the lower region of the compressor.
In FIG. 1, reference numerals 15 and 16 designate a suction pipe and discharge pipe, respectively, and reference numeral 18 designates a discharge chamber. Also, reference numerals 19 and 20 designate oil and an oil propeller, respectively.
In the scroll compressor having the above described configuration, if the rotor 5 rotates in the stator 4 upon receiving power, the crank shaft 6 is rotated by the rotor 5, thus causing the orbiting scroll 7, which is coupled to the crank shaft 6 by use of the crank pin 10, to perform an orbiting movement along an orbiting radius between the center of the crank shaft 6 and the center of the orbiting scroll 7.
Accordingly, the compression chamber 21, which is defined between the orbiting wrap 7a and the fixed wrap 8a, has a volume reduction by continuous orbiting movement of the orbiting scroll 7, resulting in compression of refrigerant gas suctioned thereinto. The compressed high-pressure refrigerant gas is discharged into the discharge chamber 18 through the outlet 17 of the fixed scroll 8. In turn, the refrigerant gas in the discharge chamber 18 is guided into the lower region of the compressor through the guidance paths 23 of the fixed scroll 8, and thereafter, is discharged to the outside through the discharge pipe 16.
FIG. 2 is a partially enlarged sectional view of FIG. 1.
As shown in FIG. 2, the main frame 2 has an oil supply screw 24. During operation of the compressor, the oil supply screw 24 allows oil, which is supplied through the crank shaft 6 into a backpressure space C1, which is defined between the orbiting scroll 7 and the main frame 2 and maintains a high pressure, into a space C2 which is defined between the fixed scroll 8 and the main frame 2 and maintains a low pressure.
The oil supply screw 24, as shown in FIG. 3, has a stepped screw body 25 having upper and lower portions of different diameters. The upper larger diameter portion of the screw body 25 is externally formed with screw threads 26, to allow the oil supply screw 24 to be screwed into a screw bore 2a formed in the main frame 2.
An orifice 27 is perforated through the center of the screw body 25. To allow an appropriate amount of oil to be supplied therethrough without interference of a discharge pressure of the oil, the orifice 27 includes a center hole 28 perforated in the upper portion of the screw body 25 and a slender hole 29 perforated in the lower portion of the screw body 25 to communicate with the center hole 28. The slender hole 29 has a smaller diameter than that of the center hole 28 and is drilled to be positioned at the center of the center hole 28.
However, in the oil supply screw of the conventional scroll compressor, since the slender hole constituting the orifice has an extremely small diameter and an entrance end thereof has a flat plane configuration, various impurities and sludge contained in the oil may accumulate at the entrance end, and be introduced into the slender hole of the oil supply screw.
Accordingly, there is a problem in that the slender hole of the oil supply screw may be clogged with the various impurities and sludge contained in the oil. This hinders an appropriate amount of oil to be supplied into the compression unit, and hence, results in deterioration in the performance and reliability of the compressor.
Therefore, the present invention has been made in view of the above problem, and it is an object of the present invention to prevent a slender hole of an oil supply screw from being clogged with sludge, the oil supply screw being provided between a backpressure space, which is defined between an orbiting scroll and a main frame, and a space which is defined between a fixed scroll and the main frame, and adapted to supply oil from the backpressure space into the space.
The object is achieved with the features of the claims.
The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view illustrating the inner configuration of a general scroll compressor;
FIG. 2 is a partially enlarged sectional view of FIG. 1;
FIG. 3 is a half-cut perspective view illustrating the configuration of an oil supply screw of FIG. 2;
FIG. 4 is a partially enlarged sectional view illustrating an oil supply structure according to a first embodiment of the present invention;
FIG. 5 is a partially enlarged sectional view illustrating an oil supply structure according to a second embodiment of the present invention;
FIGS. 6A and 6B are a bottom perspective view and a partially enlarged sectional view, respectively, illustrating an oil supply screw according to a third embodiment of the present invention;
FIG. 7 is a half-cut perspective view illustrating the configuration of an oil supply screw according to a first example as a reference;
FIG. 8 is a sectional view illustrating the supply of oil through the oil supply screw of FIG. 7;
FIG. 9 is a sectional view taken along the arrowed lines A-A' of FIG. 8;
FIG. 10 is a half-cut perspective view, illustrating the configuration of an oil supply screw according to a second example as a reference;
FIG. 11 is a partially enlarged sectional view illustrating an oil supply structure according to a third example as a reference;
FIG. 12 is an enlarged sectional view of the circle "A" of FIG. 11;
FIGS. 13A and 13B are partially enlarged sectional views illustrating a closed state and opened state of the oil supply structure of FIG. 11, respectively;
FIG. 14 is a partially enlarged sectional view illustrating an oil supply structure according to a fourth example as a reference;
FIG. 15 is a partially enlarged sectional view illustrating an oil supply structure according to a fifth example as a reference; and
FIGS. 16A and 16B are partially enlarged sectional views illustrating a closed state and opened state of the oil supply structure of FIG. 15, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the configuration of the present invention and examples as a reference will be explained in detail with reference to the accompanying drawings.
In the following description, the constituent elements of the present invention respectively corresponding to those of the prior art are designated by the same reference numerals.
Similar to the prior art, the oil supply screw of a scroll compressor according to the present invention is configured to be screwed into the screw bore 2a of the main frame 2 perforated between the backpressure space C1 and the space C2 (See FIG. 2). Here, the backpressure space C1 is defined between the orbiting scroll 7 and the main frame 2 and maintains a high pressure, whereas the space C2 is defined between the fixed scroll 8 and the main frame 2 and maintains a low pressure.
As shown in FIG. 3, the oil supply screw 24 has the screw body 25, which is externally formed with the screw threads 26 to allow the oil supply screw 24 to be screwed into the screw bore 2a of the main frame 2, and the orifice 27 perforated through the center of the screw body 25. Through the orifice 27, oil in the backpressure space C1 is able to be supplied into the space C2 defined between the fixed scroll 8 and the main frame 2.
The orifice 27 includes the center hole 28, which is longitudinally perforated through the center of the upper portion of the screw body 25, and the slender hole 29 perforated through the lower portion of the screw body 25 coaxially with the center hole 28.
The above described oil supply structure of the scroll compressor according to the present invention is characterized in that a lower entrance end of the oil supply screw 24a has a non-flat-plane configuration to provide a sludge discharger 30 in order to prevent various impurities and sludge, etc. contained in oil from accumulating at the lower entrance end of the oil supply screw 24.
Referring to FIG. 4 illustrating a first embodiment of the present invention in sectional view, the sludge discharger 30 may include a conical inclined surface 31 formed at a periphery of the lower entrance end of the oil supply screw 24. The steeper the inclined surface 31, the more easily the inclined surface 31 can achieve discharge of sludge.
Referring to FIG. 5 illustrating a second embodiment of the present invention in sectional view, in addition to the conical inclined surface 31 formed at a periphery of the lower entrance end of the oil supply screw 24, the screw body 25 of the oil supply screw 24 may have stepped upper and lower portions having different diameters from each other to define a sludge retaining space 35 between the screw body 25 and the screw bore 2a of the main frame 2.
With the above described configuration of the present embodiment, when sludge slides along the inclined surface 31 of the screw body 25 and is discharged from the oil supply screw 24, the sludge is guided into the sludge retaining space 35 around an outer peripheral surface of the screw body 25 having a different angle from that of the inclined surface 31, and thus, has no risk of being returned directly from the sludge retaining space 35 onto the inclined surface 31 of the screw body 25.
FIGS. 6A and 6B illustrate a third embodiment of the present invention, and more particularly, FIG. 6A is a bottom perspective view and Fig. 6B is a sectional view.
As shown, the sludge discharger 30 of the present embodiment may include a slender rod 32 forming a lower portion of the screw body 25, and a plurality of reinforcing ribs 33 uniformly arranged around the slender rod 32 to reinforce the structural strength of the slender rod 32. Here, the plurality of reinforcing ribs 33 may have approximately a cruciform arrangement and be shaped such that each has an inclined edge 34 starting from an entrance end of the screw body 25.
FIG. 7 is a half-cut perspective view illustrating the configuration of the oil supply screw according to a first example as a reference.
As shown, the oil supply screw 24 of the present reference example is characterized in that an orifice 40 thereof includes a center hole 41 longitudinally perforated through the center of the upper portion of the oil supply screw 24, an eccentric hole 42 longitudinally perforated through the lower portion of the oil supply screw 24 eccentric to the center of the oil supply screw 24, and an oil supply hole 43 defined by an overlapped portion of the center hole 41 and eccentric hole 42.
The oil supply hole 43 is an actual oil supply passage of the oil supply screw 24. A supply amount of oil is proportional to the size of the oil supply hole 43, and the size of the oil supply hole 43 is inversely proportional to an eccentric distance S between the center hole 41 and the eccentric hole 42.
Explaining the oil supply hole 43 in more detail with reference to FIG. 9, when the center hole 41 and eccentric hole 42 have the same diameter as each other, the longer the distance between center axes of the center hole 41 and eccentric hole 42, namely, the longer the eccentric distance S of the eccentric hole 42 relative to the center of the center hole 41, the more an overlapping area between the center hole 41 and eccentric hole 42 decreases, resulting in a reduction in the supply amount of oil through the oil supply hole 43.
Conversely, the shorter the eccentric distance S of the eccentric hole 42 relative to the center of the center hole 41, the more the overlapping area between the center hole 41 and eccentric hole 42 increases, resulting in an increase in the supply amount of oil through the oil supply hole 43.
In addition, a depth of the eccentric hole 42 relative to the center hole 41 or a depth of the center hole 41 relative to the eccentric hole 42 is a factor of determining the supply amount of oil through the oil supply hole 43. That is, the supply amount of oil is proportional to the depth. Accordingly, the higher the height of the oil supply hole 43 between the overlapped center hole 41 and eccentric hole 42, the more the supply amount of oil through the oil supply hole 43 increases. Conversely, the lower the height of the oil supply hole 43, the more the supply amount of oil through the oil supply hole 43 decreases.
In this case, assuming that the oil supply hole 43 has the same size, the supply amount of oil through the oil supply hole 43 varies depending on the height of the oil supply hole 43. Accordingly, the supply amount of oil through the oil supply hole 43 can be regulated on the basis of various conditions depending on the size and height of the oil supply hole 43.
FIG. 8 is a sectional view illustrating the supply of oil through the oil supply of Fig. 7.
As shown, if the compressor begins to operate, the backpressure space C1 between the orbiting scroll 7 and the main frame 2 forms a high pressure chamber, whereas the space C2 between the fixed scroll 8 and the main frame 2 forms a low-pressure chamber.
Also, the oil, which is stored in a lower region of the compressor, is supplied into the backpressure space C1 between the orbiting scroll 7 and the main frame 2 through the oil supply path 6a of the crank shaft 6. Subsequently, the oil is again supplied into the low-pressure space C2 between the fixed scroll 8 and the main frame 2 through the oil supply screw 24.
In this case, the supply of oil is achieved through the orifice 40 defined in the screw body 25 of the oil supply screw 24. The oil in the backpressure space C1 is first introduced into the eccentric hole 42, and then, is supplied into the center hole 41 by passing through the oil supply hole 43 that is defined by the overlapped eccentric hole 42 and center hole 41. Thereby, the oil is finally supplied into the space C2 between the fixed scroll 8 and the main frame 2.
As stated above, the supply amount of oil is determined on the basis of the size of the oil supply hole 43 between the center hole 41 and the eccentric hole 42 as well as the height of the oil supply hole 43 depending on the depth of the eccentric hole 42 relative to the center hole 41 or the depth of the center hole 41 relative to the eccentric hole 42. The size of the oil supply hole 43, as shown in FIG. 9, is inversely proportional to the eccentric distance S of the eccentric hole 42 relative to the center of the center hole 41.
FIG. 10 is a half-cut perspective view illustrating the configuration of the oil supply screw according to a second example as a reference.
As shown, instead of forming the center hole 41 of the orifice 40 in the upper portion of the screw body 25 as described in the previously described reference example, the oil supply screw 24 of the present reference example is characterized in that the orifice 40 thereof includes the center hole 41 longitudinally perforated through the center of the lower portion of the screw body 25, the eccentric hole 42 longitudinally perforated through the upper portion of the screw body 25 eccentric to the center hole 41, and the oil supply hole 43 defined by an overlapped portion of the center hole 41 and eccentric hole 42.
As will be understood from the present reference example, the orifice of the oil supply screw may be modified in various manners on the basis of a variety of requirements for the orifice 40 of the screw body 25, for example, a requirement in that an oil discharge portion must be close to a lower side of the orbiting scroll 7 when oil is supplied to an upper side of the orbiting scroll, or other processing conditions of the center hole 41 and eccentric hole 42.
FIG. 11 is a partially enlarged sectional view illustrating an oil supply structure according to a third example as a reference.
As shown, the present reference example is characterized in that an intermittent oil supplier 50 is provided to supply the oil in the backpressure space C1, which is defined between the orbiting scroll 7 and the main frame 2, into an Oldham's ring key groove 7c of the orbiting scroll 7 through the oil supply screw 24, the intermittent oil supplier 50 being opened and closed by orbiting movement of the orbiting scroll 7.
As shown in FIG. 12, the intermittent oil supplier 50 includes an oil supply bore 51 vertically defined in an upper portion of the main frame 2 for allowing the oil supply screw 24 to be screwed thereinto, and a communication bore 52 horizontally defined in the main frame 2 in a lateral direction of the backpressure space C1 for allowing communication between the oil supply bore 51 and the backpressure space C1.
To prevent the oil supply screw 24 from being separated from the oil supply bore 51, the oil supply bore 51 has a centrally protruding stepped locking portion 56 formed at a lower end thereof. The centrally protruding stepped locking portion 56 is configured to centrally define an inlet hole 55, thus allowing the oil, having been passed through the communication bore 52, to be introduced into the oil supply bore 51.
With the above described configuration, as shown in FIGS. 13A and 13B, the oil supply bore 51, which is vertically perforated in the upper portion of the main frame 2, is opened and closed by orbiting movement of the orbiting scroll 7. FIG. 13A is a sectional view illustrating the closed state of the oil supply bore 51, whereas FIG. 13B is a sectional view illustrating the opened state of the oil supply bore 51.
As shown in FIG. 13A, when the oil is supplied into the backpressure space C1 between the orbiting scroll 7 and the main frame 2 through the oil supply path of the crank shaft, the oil first passes through the communication bore 52 to be introduced into the inlet hole 55, and then, is supplied into the oil supply bore 51 through the orifice 27 of the oil supply screw 24. In this case, if the oil supply bore 51 is closed by the orbiting scroll 7, there is no supply of oil.
Thereafter, as shown in FIG. 13B, if the Oldham's ring key groove 7c of the orbiting scroll 7 is located above the oil supply bore 51 by orbiting movement of the orbiting scroll 7, the oil supply bore 51 is opened, and thus, the oil is able to be supplied into the Oldham's ring key groove 7c of the orbiting scroll 7. With the repetitive opening/closing operations, intermittent oil supply operation can be accomplished.
FIG. 14 is a partially enlarged sectional view illustrating an oil supply structure according to a fourth example as a reference.
As shown, similar to the above third reference example, the present reference example employs the intermittent oil supplier 50 for allowing the oil in the backpressure space C1, which is defined between the orbiting scroll 7 and the main frame 2, to be supplied into the Oldham's ring key groove 7c of the orbiting scroll 7 through the oil supply screw 24 as it is opened and closed by orbiting movement of the orbiting scroll 7.
The intermittent oil supplier 50 includes the oil supply bore 51 vertically defined in the upper portion of the main frame 2 for allowing the oil supply screw 24 to be screwed thereinto, and the communication bore 52 horizontally defined in the main frame 2 in a lateral direction of the backpressure space C1 for allowing communication between the oil supply bore 51 and the backpressure space C1.
The present reference example is characterized in that the communication bore 52, which is perforated in the main frame 2 in the lateral direction of the backpressure space C1, has one end in which a plug 53 is screwed. As a result of separably screwing the plug 53 into the communication bore 52, there is an advantage in that cleaning of the communication bore 52 can be more easily performed.
In FIG. 14, reference numerals 55 and 56 designate inlet hole and centrally protruding stepped locking portion, respectively.
FIG. 15 is a partially enlarged sectional view illustrating an oil supply structure according to a fifth example as a reference.
As shown, similar to the above third and fourth reference examples, the present reference example employs the intermittent oil supplier 50 for allowing the oil in the backpressure space C1, which is defined between the orbiting scroll 7 and the main frame 2, to be supplied into the Oldham's ring key groove 7c of the orbiting scroll 7 through the oil supply screw 24 as it is opened and closed by orbiting movement of the orbiting scroll 7.
The intermittent oil supplier 50 includes the inclined oil supply bore 51 obliquely perforated between the backpressure space C1 and thrust planes of the main frame 2 and orbiting scroll 7 for allowing the oil supply screw 24 to be screwed thereinto.
Similar to the above third and fourth reference examples, the oil supply bore 51 is formed at an upper end thereof with an oil passage 54 having a slightly larger diameter than that of the oil supply bore 51, and at the lower end thereof with the centrally protruding stepped locking portion 56 for preventing the oil supply screw 24 from being separated from the oil supply bore 51, the centrally protruding stepped locking portion 56 defining the inlet hole 55.
With the above described configuration, as shown in FIGS. 16A and 16B, the oil supply bore 51, which is obliquely perforated in the main frame 2, is opened and closed by orbiting movement of the orbiting scroll 7. FIG. 16A is a sectional view illustrating the closed state of the oil supply bore 51, whereas FIG. 16B is a sectional view illustrating the opened state of the oil supply bore 51.
As shown in FIG. 16A, when the oil is supplied into the backpressure space C1 between the orbiting scroll 7 and the main frame 2 through the oil supply path of the crank shaft, the oil is supplied into the oil supply bore 51 through the orifice 27 of the oil supply screw 24. In this case, if the oil supply bore 51 is closed by the orbiting scroll 7, there is no supply of oil.
Thereafter, as shown in FIG. 16B, if the Oldham's ring key groove 7c of the orbiting scroll 7 is located above the oil supply bore 51 by orbiting movement of the orbiting scroll 7, the oil supply bore 51 is opened, and thus, the oil is able to be supplied into the Oldham's ring key groove 7c of the orbiting scroll 7. With the repetitive opening/closing operations, intermittent oil supply operation can be accomplished.
As apparent from the above description, the oil supply structure of a scroll compressor according to the present invention has the following several effects.
The present invention employs a sludge discharger having a non-flat-plane configuration, which is provided at an entrance end of an oil supply screw between a backpressure space, which is defied between an orbiting scroll and a main frame, and a space between a fixed scroll and the main frame. Providing the sludge discharger has the effect of preventing a slender hole of the oil supply screw from being clogged with sludge, and thus allowing an appropriate amount of oil to be supplied into a compression unit. This results in improvement in the performance and reliability of the compressor.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the invention as disclosed in the accompanying claims.

Claims

An oil supply structure of a scroll compressor for supplying oil from a backpressure space (C1), which is defined between an orbiting scroll (7) and a main frame (2), into a space (C2) which is defined between a fixed scroll (8) and the main frame (2), by use of an oil supply screw (24), which is screwed into a screw bore (2a) of the main frame perforated between the backpressure space (C1) and the space (C2), wherein
the oil supply screw (24) includes:
an orifice (27) having a center hole (28) longitudinally perforated through the center of an upper portion of a screw body (25) of the oil supply screw and a slender hole (29) continuously perforated below the center hole to have the same axis as that of the center hole;

a lower entrance end being located such that oil in the backpressure space (C1) enters the oil supply screw (24) through the lower entrance end and is supplied to the space (C2), characterized in that the structure comprises a sludge discharger (30) having a non-flat-plane configuration being formed at the lower entrance end of the screw body, said sludge discharger comprising a surface inclined relative to said axis for allowing sludge to slide along said inclined surface.
The oil supply structure according to claim 1, wherein the sludge discharger (30) is formed by a conical inclined surface (31) at a periphery of the lower entrance end of the screw body (25).
The oil supply structure according to claim 1 or 2, wherein the screw body (25) has stepped upper and lower portions having different diameters from each other.
The oil supply structure according to any of claims 1 to 3, wherein the sludge discharger (30) is formed by a slender rod (32) at the lower entrance end of the screw body, a plurality of reinforcing ribs (33) being uniformly arranged along an outer periphery of the slender rod, and
each of the reinforcing ribs (33) has an inclined edge (34) starting from a lower entrance end face of the screw body (25).