# Patent

## Title
Horizontal type scroll compressor having discharge guide between a main scroll and a motor housing

## Abstract

A horizontal type scroll compressor includes a main scroll through which a crankshaft is rotatably inserted, the main scroll having a fixed wrap formed on a front surface thereof, and an orbiting scroll coupled to the crankshaft inserted through the main scroll and having an orbiting wrap. A discharge port is formed toward one side surface in an axial direction of the main scroll facing a driving motor. A guide member is coupled to the one side surface of the main scroll, and has a discharge guide portion accommodating the discharge port.

## Background
CROSS-REFERENCE TO RELATED PATENT APPLICTIONS
This application is a U.S National Stage Application under 35 U.S.C. §371 of PCT Application No. PCT/KR2013/001309, filed Feb. 20, 2013, which claims priority to Korean Patent Application No. 10-2012-0023539, filed Mar. 7, 2012, whose entire disclosures are hereby incorporated by reference.
TECHNICAL FIELD
The present disclosure relates to a horizontal type scroll compressor capable of being applied to vehicles.
BACKGROUND ART
In general, compressors are devices for compressing fluid such as refrigerant gas and the like, and may be classified into a rotary compressor, a reciprocal compressor, a scroll compressor and the like according to a method of compressing the fluid.
The scroll compressor is a high-efficiency and low-noise compressor which is widely applied to an air-conditioning field. The scroll compressor operates in the following manner. That is, while two scrolls respectively having a fixed wrap and an orbiting wrap orbit relatively, a plurality of compression chambers are formed as a pair between the fixed wrap and the orbiting wrap of each scroll. As their volumes of the compression chambers decrease while they continuously move toward their center, a refrigerant is continuously sucked, compressed and discharged.
Behaviors of the scroll compressor may depend on shapes of the fixed wrap and the orbiting wrap. Although they can have a random shape, the fixed wrap and the orbiting wrap typically have a shape of an involute curve which is easy to be processed. The involute curve refers to a curve corresponding to a track drawn by an end of a string, which is wrapped around a base circle having a random radius, when the string is unwound. Upon the use of the involute curve, wraps have a uniform thickness and accordingly a coefficient of volume change is constant. Therefore, in order to obtain a satisfactory compression ratio, the number of turns of the wrap has to increase. However, it also causes the compressor to increase in size.
FIG. 1 is a sectional view showing a structure of a horizontal type scroll compressor according to the related art.
As shown in FIG. 1, a scroll compressor according to the related art includes a main frame 2 and a sub frame 3 disposed within an inner space 11 of a casing 1 in a horizontal direction with a predetermined interval, a driving motor 4 installed between the main frame 2 and the sub frame 3 to generate a rotational force, and a crankshaft 5 formed in a center of a rotor 42 of the driving motor 4 and penetrating through the main frame 2 to be coupled to the orbiting scroll 7 so as to transfer the rotational force of the driving motor 4 thereto.
A fixed scroll 6 is fixed to a front of the main frame 2, and an orbiting scroll 7 is engaged with the fixed scroll 6 to form two compression chambers S as a pair which move continuously. An Oldham's ring 8 is installed between the orbiting scroll 7 and the main frame 2 such that the orbiting scroll 7 can orbit without rotation.
A shaft receiving hole 21 for supporting the crankshaft 5 in a radial direction is formed in the central portion of the main frame 2, and a main bearing 22 for supporting the crankshaft 5 in a radial direction is installed in the shaft receiving hole 21.
A fixed wrap 62 forming the pair of compression chambers S is formed in an involute shape on a rear surface of a fixed disk 61 of the fixed scroll 6. A suction port (not shown) is formed at a side surface of the fixed disk 61 to be directly connected to a suction pipe such that a refrigerant can be sucked into the compression chambers S.
A discharge port 63 is formed at a center of a front surface of the fixed disk 61 such that a refrigerant gas compressed in the compression chambers S can be discharged into the inner space 11 of the casing 1. A discharge valve 9 for opening or closing the discharge port 63 to prevent the refrigerant gas from flowing backwardly is disposed at a front surface of the fixed scroll 6. A discharge cover 64 may be hermetically coupled to the front surface of the fixed disk 61 to form an intermediate space 14 with accommodating the discharge valve 9 therein. A gas passage F for communicating the intermediate space 14 with the inner space 11 of the casing 1 may be formed through the fixed scroll 6 and the main frame 2.
An orbiting wrap 72 which forms two compression chambers S as a pair together with the fixed wrap 62 of the fixed scroll 6 is formed in an involute shape on a front surface of an orbiting disk 71 of the orbiting scroll 7. A boss portion 73 is formed at a center of a rear surface of the orbiting disk 61. The boss portion 73 is coupled to the crankshaft 5 to transfer the rotational force from the driving motor 4 to the crankshaft 5. A pin bearing 74 for support between the crankshaft 5 and the boss portion 73 in a radial direction is installed on an inner circumferential surface of the boss portion 73.
An unexplained reference numeral 12 denotes an inlet, 13 denotes an outlet, 31 denotes a sub bearing for supporting the crankshaft 4 in a radial direction, 41 denotes a stator of the driving motor 4, and 51 denotes an oil passage.
Hereinafter, description will be given of an operation of the related art scroll compressor.
That is, when power is applied to the driving motor 4, the crankshaft 5 rotates together with a rotor 42 of the driving motor 4. Accordingly, the orbiting scroll 7 orbits on an upper surface of the main frame 2 by the Oldham s ring 8 as far as an eccentric distance, and simultaneously, two, namely, a pair of compression chambers S are continuously formed between the fixed wrap 62 and the orbiting wrap 72. As the compression chambers move, with their volumes decreased, toward their center in response to a continuous orbiting motion of the orbiting scroll 7, a refrigerant gas is continuously sucked, compressed and then discharged in the intermediate space 14. The refrigerant discharged into the intermediate space 14 flows into the inner space 11 and is discharged into a refrigerating cycle via the outlet 13.
DISCLOSURE OF INVENTION
Technical Problem
However, in the related art horizontal type scroll compressor, the refrigerant discharged out of the compression chambers S flows into the inner space 1 of the casing 1 at the motor side via the intermediate space 14 formed by the discharged cover 64 and the gas passage F disposed through the fixed scroll 6 and the main frame 2. This makes the discharge path of the refrigerant complicated, causing difficulty in fabricating related components and assembling them for sealing.
Further, as the crankshaft 5 is coupled to the rear surface of the orbiting scroll 7, an application point to which a repulsive force of a refrigerant is applied is spaced apart in a vertical direction from an application point to which a reaction force for offsetting the repulsive force is applied during compression. Accordingly, the orbiting scroll 7 is inclined during operation, increasing vibration or noise. Especially, for the horizontal type scroll compressor, the orbiting scroll 7 is further inclined by its own weight, which may be likely to further increase the vibration or noise of the compressor.
Solution to Problem
Therefore, to obviate those problems, an aspect of the detailed description is to provide a horizontal type scroll compressor, capable of simplifying fabrication of related components and assembly parts for sealing by simplifying a discharge path of a refrigerant discharged from compression chambers into a discharge space.
Another aspect of the detailed description is to provide a horizontal type scroll compressor, capable of overcoming a problem of an inclination of an orbiting scroll, in a manner of controlling an application point of a repulsive force of a refrigerant and an application point of the corresponding reaction force to be applied onto the same portion.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a horizontal type scroll compressor including a casing, a driving motor installed within an inner space of the casing and having a stator and a rotor, a crankshaft coupled to the rotor of the driving motor to transfer a rotational force, a main scroll through which the crankshaft is rotatably inserted, the main scroll having a fixed wrap on a front surface thereof, and an orbiting scroll coupled to the crankshaft inserted through the main scroll, and having an orbiting scroll engaged with the fixed wrap to form a first compression chamber and a second compression chamber on an outer surface and an inner surface thereof. Here, a discharge port may be formed toward one side surface in an axial direction of the main scroll facing the driving motor. A guide member may be coupled to the one side surface of the main scroll, and have a discharge guide portion accommodating the discharge port therein for guiding a refrigerant into the inner space of the casing.
A main bearing for supporting the crankshaft may be coupled to the guide member.
The discharge port may be formed within a range of an outer diameter of the main bearing.
The guide member may include a guide body formed in an annular shape, a shaft receiving portion formed through a middle portion of an inner circumferential surface of the guide body, the crankshaft being coupled therethrough, a bearing mounting portion formed on one side surface of the shaft receiving portion in an axial direction, the main bearing being mounted thereon, and a discharge guide portion formed on the other surface of the shaft receiving portion in the axial direction, and accommodating the discharge port therein, wherein the discharge guide portion guides a refrigerant discharged from the discharge port into the inner space of the casing.
The shaft receiving portion may extend from an inner circumferential surface of the guide body and be bent toward one side surface of the main scroll in an axial direction, and a discharge passage accommodating the discharge port may be formed between an inner circumferential surface of the shaft receiving portion and an inner circumferential surface of the guide body.
In accordance with another exemplary embodiment of the detailed description, there is provided a horizontal type scroll compressor including a motor housing having an inner space for installation of a driving motor therein, a main scroll coupled to one side of the motor housing to seal the inner space of the motor housing and having a fixed wrap forming compression chambers, an orbiting scroll having an orbiting wrap engaged with the fixed wrap of the main scroll and coupled to a crankshaft inserted through the main scroll, the orbiting scroll forming a first compression chamber and a second compression chamber on an outer surface and an inner surface of the orbiting wrap while performing an orbiting motion, and a front housing hermetically coupled to the main scroll, the front housing accommodating the orbiting scroll. Here, a bearing guide for installation of a main bearing supporting the crankshaft may be coupled toward one side surface in an axial direction of the main scroll facing the inner space of the motor housing.
A discharge port may be formed toward a surface of the main scroll, and the bearing guide may be coupled to the surface. The bearing guide may include a discharge guide portion accommodating the discharge port therein to guide a refrigerant into the inner space of the motor housing.
The bearing guide may include a guide body formed in an annular shape, and a shaft receiving portion formed through an inner circumferential surface of the guide body for insertion of the crankshaft therethrough. A discharge passage for a refrigerant, communicating with the discharge port, may be formed between the guide body and the shaft receiving portion.
The first compression chamber may be formed between two contact points P1 and P2 generated as an inner surface of the fixed wrap and an outer surface of the orbiting wrap contact each other, and the crankshaft may include an eccentric pin coupled to a shaft coupling portion of the orbiting scroll. Here, α<360 at least before the beginning of discharging when it is assumed that α is a larger angle of angles formed by two lines connecting a center O of the eccentric pin of the crankshaft and the two contact points P1 and P2, respectively.
Advantageous Effects of Invention
In accordance with the detailed description, in the horizontal type scroll compressor, a bearing guide for supporting a main bearing may be assembled to the main scroll forming the fixed scroll such that a discharge port can be formed within a range of an outer diameter of the main bearing so as to be located at a center of a shaft as close as possible, whereby a dead volume may be reduced and the compressor may decrease in size.
Also, the crankshaft may be inserted through the fixed wrap of the main scroll and the orbiting wrap of the orbiting scroll. This may allow an application point of a repulsive force of a refrigerant and an application point of a corresponding reaction point to be applied to the same portion, thereby preventing the orbiting scroll from being inclined. With forming the protrusion and the concave portion at the discharge side of the fixed wrap and the orbiting wrap, a compression ratio of a first compression chamber may be improved and a thickness of an inner end portion of the fixed wrap may increase. This may result in improvement of a wrap strength and a leakage-preventing function.



BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a longitudinal sectional view showing one exemplary embodiment of a scroll compressor according to the related art;
FIG. 2 is a perspective view showing one exemplary embodiment of a horizontal type scroll compressor in accordance with the present disclosure;
FIG. 3 is a disassembled perspective view of the horizontal type scroll compressor of FIG. 2;
FIG. 4 is an assembled longitudinal sectional view of the horizontal type scroll compressor of FIG. 2;
FIG. 5 is a disassembled perspective view showing a bearing guide in the horizontal type scroll compressor of FIG. 4;
FIG. 6 is a horizontal sectional view showing the bearing guide in the horizontal type scroll compressor of FIG. 4;
FIG. 7 is a horizontal sectional view showing one exemplary embodiment of a fixed wrap and an orbiting wrap defining a compression part in the horizontal type scroll compressor of FIGS. 4; and
FIG. 8 is an enlarged horizontal sectional view showing surroundings of final compression chambers formed by the fixed wrap and the orbiting wrap of FIG. 7.



BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings where those components are rendered the same reference number that are the same or are in correspondence, regardless of the figure number, and redundant explanations are omitted. In describing the present invention, if a detailed explanation for a related known function or construction is considered to unnecessarily divert the gist of the present invention, such explanation has been omitted but would be understood by those skilled in the art. The accompanying drawings are used to help easily understood the technical idea of the present invention and it should be understood that the idea of the present invention is not limited by the accompanying drawings. The idea of the present invention should be construed to extend to any alterations, equivalents and substitutes besides the accompanying drawings.
FIG. 2 is a perspective view showing one exemplary embodiment of a horizontal type scroll compressor in accordance with the present disclosure, FIG. 3 is a disassembled perspective view of the horizontal type scroll compressor of FIG. 2, FIG. 4 is an assembled longitudinal sectional view of the horizontal type scroll compressor of FIG. 2, and FIGS. 5 and 6 are a disassembled perspective view and a horizontal sectional view each showing a bearing guide in the horizontal type scroll compressor of FIG. 4.
As shown in those drawings, a horizontal type scroll compressor according to the present disclosure may include a driving motor 102 installed within a casing 101 to generate a rotational force, a main scroll 103 coupled to one side (hereinafter, referred to as a front side) of the casing 101 to form a compression part as well as covering the casing 101, an orbiting scroll 104 coupled to a front side of the main scroll 103 to form the compression part together with the main scroll 103, and an oil pump 105 installed at another side (hereinafter, referred to as a rear side) of the driving motor 102 to supply oil stored within the casing 101 into the compression part.
The casing 101 may include a motor housing 111 having both ends open and the driving motor 102 installed therein, a pump housing 112 for covering the rear open end of the motor housing 111 and mounting the oil pump therein, and a front housing 113 coupled to the main scroll 103, which covers the front open end of the motor housing 111, so as to accommodate the orbiting scroll 104 therein.
Here, the main scroll 103 may be installed between the motor housing 111 and the front housing 113 to define a part of the casing 101. The front housing 113 may be coupled to the motor housing 111, with being spaced apart from the motor housing 111 by a thickness of a frame portion 131 of the main scroll 103, by use of coupling bolts 115, which are long enough to be inserted through the frame portion 131, which will be explained later.
The motor housing 111, the main scroll 103 and the front housing 113 may be coupled in an aligned state by using a plurality of reference pins 117, which are inserted through reference recesses (not shown) formed on the motor housing 111 and reference recesses 113c formed on the front housing 113, and reference holes 131f formed on the main scroll 103 in a sequential manner.
The motor housing 111 may have a cylindrical shape, and its both open ends may be provided with coupling bores 111a and 111b for coupling of bolts. A terminal part 114 electrically connected to a coil 121a of the driving motor 102 may be formed at one side on an outer circumferential surface of the motor housing 111.
The driving motor 102 may include a stator 121 fixed to the motor housing 111 in a manner of shrink fitting or bolt coupling, and a rotor 122 rotatably coupled into the stator 121. The stator 121 may be wound by a coil 121a, and a crankshaft 125 for transferring the rotational force to the orbiting scroll 104 may be coupled into a center of the rotor 122.
An oil passage 125a may be extendedly formed in a central portion of the crankshaft 125 in a lengthwise direction of the crankshaft 125. An oil pump 105 may be installed at one end (e.g., a rear end) of the crankshaft 125 for supplying oil stored in the pumping housing 112 to another end (e.g., a front end) of the crankshaft 125. The oil pump 105 may be implemented as a positive displacement pump having a trochoid gear.
A diameter-extending portion 125b which is inserted into a main bearing 181 disposed in a bearing guide 107 to be explained later may be formed at a front end of the crankshaft 125. An eccentric pin 125c inserted into a shaft coupling portion 141b of the orbiting scroll 104 to be explained later may be formed at an end portion of the diameter-extending portion 125b. A bush 185 to be explained later may be coupled to the shaft coupling portion 141b and a pin bearing 182 for supporting the eccentric pin 125c may be coupled into the bush 185. The pin bearing 182 may appropriately be implemented as a needle bearing having a characteristic that its load bearing capacity is great as compared with its diameter. The eccentric pin 125c of the crankshaft 125 may be inserted into the pin bearing 182 implemented as the needle bearing to be supported in a radial direction.
The pump housing 112 may be formed in a shape of a cap whose front end is open. A coupling hole 112a which aligns with the rear coupling bore 111b of the motor housing 111 may be formed on the open end of the pump housing 112.
A bearing support portion 112b in which a sub bearing 183 for supporting the crankshaft 125 is installed may be formed in a central portion of the pump housing 112, and the oil pump 105 may be installed on the other side of the bearing support portion 112b. 
An outlet 112c for guiding a refrigerant discharged from the compression part to be introduced into a refrigerating cycle may be formed at one side of the pump housing 112. A discharge pipe (not shown) may be connected to the outlet 112c. 
The front casing 113 may be formed in a shape of a cap whose rear end is open, and through holes 113a may be formed through the open end of the front housing 113 to align with coupling holes 131a of the main scroll 103 to be explained later.
First key recesses 113b into which first keys 162a of an Oldham's ring 106 to be explained later are slidably coupled may be recessed into a front surface at an inner side of the front housing 113. The first key recesses 113b may be formed long in a radial direction with an interval of 180°
The main scroll 103 may include a frame portion 131 formed in a shape of plate, coupled to the front open end of the motor housing 111 and forming a fixed plate of the main scroll 103, and a fixed side wrap portion 132 formed at a front of the frame portion 131 and engaged with an orbiting wrap 142 of the orbiting scroll 104 to be explained later to form a first compression chamber S1 and a second compression chamber S2. The fixed side wrap portion 132 defines a fixed wrap. Hereinafter, it will thusly be briefly referred to as a fixed wrap.
The frame portion 131 may be formed in a shape of a plate having a predetermined thickness, and include coupling holes 131a formed on an edge thereof to align with the front coupling bore 111a of the motor housing 111 and the through holes 113a of the front housing 113, such that coupling bolts 115 are coupled all thereinto.
An inlet 131b may be formed on a side surface of the frame portion 131, and a suction pipe (not shown) may be connected to the inlet 131b. 
A shaft hole 131c through which the front end of the crankshaft 125 is inserted may be formed in a central portion of the frame portion 131. A discharge port 131d may be formed adjacent to the shaft hole 131c such that a refrigerant compressed in the compression chambers S1 and S2 is discharged toward the motor housing 111. The discharge port 131d may also be formed out of a range of an outer diameter of a main bearing 181, which will be explained later, to prevent it from overlapping the main bearing 181. However, in this structure, a great dead volume may be generated in a central portion of a scroll. Therefore, the discharge port 131d may preferably be formed adjacent to the shaft hole 131c if possible. Bypass ports 131e for bypassing in advance a part of a refrigerant compressed in the compression chambers S1 and S2 may be formed adjacent to the discharge port 131d. 
A bearing guide 107 for supporting the main bearing 181 may be coupled to a rear side surface of the frame portion 131 by use of bolts 116.
The bearing guide 107, as shown in FIGS. 4 to 6, may include a guide body 171 formed in a cylindrical shape, a shaft receiving portion 172 formed through a middle of an inner circumferential surface of the guide body 171 and having a through hole for insertion of the crankshaft 125 therethrough. The guide body 171 may have one end bent to be coupled to the rear side surface of the main scroll 103 by use of the bolts 116. The guide body 171 may have an area large enough for a discharge guide portion 174, which will be explained later, to accommodate the discharge port 131d and the bypass ports 131e therein.
A bearing mounting portion 173 in which the main bearing 181 implemented as a ball bearing is inserted may be formed on one side surface of the shaft receiving portion 172. The discharge guide portion 174 for guiding a refrigerant discharged from the compression chambers toward the motor housing 111 may be formed at another side surface of the shaft receiving portion 172.
The bearing mounting portion 173 may be formed in a circular shape to have approximately the same inner diameter as an outer diameter of the main bearing 181.
The discharge guide portion 174 may include a first guide passage 175 corresponding to an annular space defined by the guide body 171, the shaft receiving portion 172 and a rear side surface of the main scroll 103, and accommodating the discharge port 131d and the bypass ports 131e therein, and a second guide passage 176 formed by opening an outer circumferential surface of the first guide passage 175 such that a refrigerant introduced into the first guide passage 175 is discharged toward the motor housing 111. The second guide passage 176 may be formed in plurality which are arranged along the outer circumferential surface of the first guide passage 175 with a predetermined interval.
In the meantime, the orbiting scroll 104 may include an orbiting plate 141 formed in a shape of plate to define a bearing surface together with the frame portion 131 of the main scroll 103, and an orbiting side wrap portion 142 formed on a rear side of the orbiting plate 141 and engaged with the fixed wrap 132. Here, the orbiting side wrap portion 142 may form an orbiting wrap. Therefore, the orbiting side wrap portion 142 may be briefly referred to as an orbiting wrap, hereinafter.
Second key recesses 141a which are long in a radial direction to allow second keys 162b of Oldham's ring 106 to he slidably inserted may be recessed into a front surface of the orbiting plate 141. The second key recesses 141a may be formed with an interval of 180° and have approximately 90° phase difference from the first key recesses 113b of the front housing 113.
The shaft coupling portion 141b in which the eccentric pin 125c of the crankshaft 125 is inserted may be formed through the center of the orbiting plate 141. The bush 185 may be inserted into the shaft coupling portion 141b. The bush 185 may be undetachably fixed to the shaft coupling portion 141b by a bush fixing member, such as a snap ring 186, which is fixedly inserted into a fixing groove 125d formed on the eccentric pin 125c. 
A pin bearing 182 in which the eccentric pin 125c of the crankshaft 125 is inserted may be coupled to the bush 185. The pin bearing 182 may be implemented as a needle bearing as aforementioned.
Meanwhile, the fixed wrap 132 and the orbiting wrap 142 may be formed in a shape of involute curve. Upon the use of the involute curve, wraps have a uniform thickness and accordingly a coefficient of volume change is constant. Therefore, in order to obtain a satisfactory compression ratio, the number of turns of the wrap has to increase. However, it also causes the compressor to increase in size. Therefore, according to this exemplary embodiment, as shown in FIGS. 7 and 8, when it is assumed that a compression chamber, which is formed between two contact points P1 and P2 generated as an inner surface of the fixed wrap 132 comes in contact with an outer surface of the orbiting wrap 142, is referred to as the first compression chamber S1, the first compression chamber S1 may be formed such that an angle defined by two lines which connect a center O of the eccentric pin 125c of the crankshaft 125 to the respective two contact points P1 and P2 is smaller than 360 and a distance l between normal vectors at each contact point P1 and P2 is greater than 0. Accordingly, the first compression chamber S1 just before discharging may have a smaller volume, as compared with having the fixed wrap and the orbiting wrap in the shape of the involute curve. This may result in an increase in a compression ratio. In addition, the fixed wrap 132 and the orbiting wrap 142 may have a shape formed by connecting a plurality of circular arcs having different diameters and start points from one another, and the outermost curve may have an approximately oval shape with a major axis and a minor axis.
A protrusion 135 may be formed near an inner end portion of the fixed wrap 132. The protrusion 135 may protrude toward the shaft coupling portion 141b of the orbiting scroll 104. A contact portion 136 may further protrude from the protrusion 135. That is, the inner end portion of the fixed wrap 132 may be formed to be thicker than the other portions in thickness. This may improve a wrap strength of the inner end portion which is affected by the greatest compression force of the fixed wrap 132, resulting in enhancement of durability.
As shown in FIG. 8, the thickness of the fixed wrap 132 may gradually decrease, starting from the inner contact point P1, which forms the first compression chamber Si at the beginning of discharging, of the two contact points P1 and P2. In detail, a first decreasing portion 137 adjacent to the contact point P1 and a second decreasing portion 138 connected to the first decreasing portion 137 may be formed. A thickness decrease rate in the first decreasing portion 137 may be greater than that in the second decreasing portion 138. After the second decreasing portion 138, the fixed wrap 132 may continuously increase in thickness for a predetermined section.
A concave portion 145 which is engaged with the protrusion 135 may be formed at the shaft coupling portion 141b of the orbiting scroll 140. One side wall of the concave portion 145 may form one contact point of the first compression chamber S1 by contacting the contact portion 136 of the protrusion 135.
The one side wall of the concave portion 145 may include a first increasing portion 146 whose thickness relatively drastically increases, and a second increasing portion 147 connected to the first increasing portion 146 and having a thickness increasing at a relatively low ratio. They correspond to the first decreasing portion 137 and the second decreasing portion 138 of the fixed wrap 132. The first increasing portion, the first decreasing portion, the second increasing portion and the second decreasing portion may be obtained as a result of bending an envelope toward the shaft coupling portion 141b. Accordingly, the inner contact point P1 forming the first compression chamber S1 may be located at the first increasing portion 146 and the second increasing portion 147 and also a length of the first compression chamber S1 just before discharging may be shortened. This may result in improvement of a compression ratio.
Another side wall of the concave portion 145 may have a shape of arc. A diameter of the arc may be decided by a wrap thickness of the end portion of the fixed wrap 132 and an orbiting radius of the orbiting wrap 142. When the end portion of the fixed wrap 132 increases in thickness, the diameter of the arc may increase. The thickness of the orbiting wrap 142 near the arc may thusly increase so as to ensure durability. Also, a compression path may extend so as to increase a compression ratio of the second compression chamber S2.
Here, a central portion of the concave portion 145 may form a part of the second compression chamber S2. The second compression chamber S2 may contact the arcuate wall of the concave portion 145. When the crankshaft 125 rotates a little bit more, one end of the second compression chamber S2 may pass through the central portion of the concave portion 145.
Meanwhile, an Oldham's ring 106 as an anti-rotation member for guiding the orbiting scroll 104 to perform an orbiting motion may be installed between a front surface of the orbiting scroll 104 and a corresponding inner rear surface of the front housing 113.
The Oldham's ring 106, as shown in FIGS. 3 and 4, may include a ring portion 161 having an annular form, and first keys 162a and second keys 162b formed on front surface and rear surface of the ring portion 161, respectively. The first keys 162a may be formed with an interval of 180, similar to the first key recesses 113b. The second keys 162b may also be formed with the interval of 180° similar to the first keys 162a. The first key recesses 113b and the second key recesses 141a may be formed in a circumferential direction by an interval of 90° in an alternating manner.
In the meantime, a sealing member 144 for forming a back pressure chamber at the front of the orbiting scroll 104 may be disposed on the front surface of the orbiting scroll 104. To this end, a sealing protrusion 141c may be formed on a circumference of the shaft coupling portion 141b of the orbiting scroll 104, and a sealing recess 141d in which the sealing member 144 is inserted may be formed on the sealing protrusion 141c. Accordingly, a back pressure chamber S3 in a high pressure atmosphere due to oil (or discharged gas), which is introduced via the oil passage 125a of the crankshaft 125, may be formed inside the sealing member 144.
An unexplained reference numeral 118 denotes a pressure separate plate, 118a denotes a gas hole, and 118b denotes an oil hole.
Hereinafter, description will be given of an operation effect of the scroll compressor with the aforementioned configuration.
That is, when power is applied to the driving motor 102, the crankshaft 125 may rotate together with the rotor 122, to transfer a rotational force to the orbiting scroll 104.
The orbiting scroll 104 may accordingly orbit by an eccentric distance with respect to the main scroll 103, thereby forming the first compression chamber S1 and the second compression chamber S2, which continuously move, between the fixed wrap 132 and the orbiting wrap 142.
The first compression chamber S1 and the second compression chamber S2 may decrease in volume while moving toward the center by the continuously orbiting motion of the orbiting scroll 104. Accordingly, a refrigerant introduced into each of the compression chambers S1 and S2 via the inlet 131b may be compressed, and then discharged via the discharge port 131d communicating with the inner final compression chamber.
The refrigerant discharged via the discharge port 131d may flow into the inner space of the motor housing 111 via the discharge guide portion 174 of the bearing guide 107 and continuously flow into the pump housing 112 via the gas hole 118a of the pressure separate plate 118, thereby being introduced into a refrigerating cycle via the outlet 112c. 
Simultaneously, the oil pump 105 which is located at the rear end of the crankshaft 125 may operate to pump up oil stored in the pump housing 112. The pumped oil may then supplied into each bearing via the oil passage 125a. 
The oil may partially be collected back into the motor housing 111 via each bearing. Some of oil which is discharged together with the refrigerant discharged from the compression chambers may be separated from the refrigerant by the bearing guide 107 and then collected back into the motor housing 111. The oil may then flow into the pump housing 112 via the oil hole 118b of the pressure separate plate 118 due to pressure difference, be pumped by the oil pump 105, and be supplied to each bearing, which series of operations may be repetitively executed.
As such, the main scroll forming the fixed scroll may be located between the motor housing and the front housing to be fixed to both of them. This may allow the fixed scroll to be installed without a separate frame, resulting in reduction of the number of components. In addition, the number of assembly parts may be reduced by coupling the motor housing, the main scroll and the front housing all together by use of long coupling bolts, reducing fabricating costs accordingly.
Also, the crankshaft may be inserted through the fixed wrap of the main scroll and the orbiting wrap of the orbiting scroll. This may allow an application point of a repulsive force of a refrigerant and an application point of a corresponding reaction point to be applied to the same portion, thereby preventing the orbiting scroll from being inclined. With forming the protrusion and the concave portion at the discharge side of the fixed wrap and the orbiting wrap, a compression ratio of a first compression chamber may be improved more than a scroll compressor having a fixed wrap and an orbiting wrap with an involute shape. Therefore, a thickness of an inner end portion of the fixed wrap may increase, which may result in improvement of a wrap strength and a leakage-preventing function.

## Claims

1. A horizontal type scroll compressor, comprising:
a casing;
a driving motor installed within an inner space of the casing and having a stator and a rotor;
a crankshaft coupled to the rotor of the driving motor to transfer a rotational force;
a main scroll through which the crankshaft is rotatably inserted, the main scroll having a fixed side wrap portion on a surface of the main scroll; and
an orbiting scroll coupled to the crankshaft inserted through the main scroll, and having an orbiting scroll wrap engaged with the fixed side wrap portion to form a first compression chamber and a second compression chamber on an outer surface of the fixed side wrap portion and an inner surface of the fixed side wrap portion, wherein a discharge port is formed toward one side surface in an axial direction of the main scroll facing the driving motor, and wherein a guide is coupled to the one side surface of the main scroll, and has a discharge guide portion that accommodates the discharge port therein to guide a refrigerant into the inner space of the casing.

2. The compressor of claim 1, wherein a main bearing that supports the crankshaft is coupled to the guide.

3. The compressor of claim 2, wherein the discharge port is formed within a range of an outer diameter of the main bearing.

4. The compressor of claim 2, further including bypass ports formed adjacent to the discharge port to bypass a portion of refrigerant compressed in the compression chambers, wherein the bypass ports are formed within a range of an outer diameter of the main bearing.

5. The compressor of claim 2, wherein the guide includes:
a guide body formed in an annular shape;
a shaft receiving portion formed through a middle portion of an inner circumferential surface of the guide body, the crankshaft being couple through the shaft receiving portion;
a bearing mounting portion formed on one side surface in an axial direction of the shaft receiving portion, the main bearing being mounted on the bearing mounting portion; and
the discharge guide portion, which is formed on the other surface of the shaft receiving portion in the axial direction, and accommodates the discharge port, wherein the discharge guide portion guides a refrigerant discharged from the discharge port into the inner space of the casing.

6. The compressor of claim 5, wherein the shaft receiving portion extends from an inner circumferential surface of the guide body and is bent toward one side surface of the main scroll in an axial direction, and wherein a discharge passage that accommodates the discharge port is formed between an inner circumferential surface of the shaft receiving portion and an inner circumferential surface of the guide body.

7. The compressor of claim 1, wherein the main scroll includes:
a frame portion hermetically coupled to one side of the casing; and
the fixed side wrap portion, which is formed on one side surface of the frame portion in an axial direction, the fixed side wrap portion being integrally formed with the frame portion, wherein a suction port that communicates with the compression chambers is formed on a circumferential surface of the frame portion, and the discharge port is formed on the one side surface of the frame portion.

8. The compressor of claim 1, wherein the first compression chamber is formed between two contact points generated as an inner surface of the fixed wrap and an outer surface of the orbiting wrap contact each other, wherein the crankshaft includes an eccentric pin coupled to a shaft coupling portion of the orbiting scroll, and wherein α<360° at least before the beginning of discharging when it is assumed that α is a larger angle of angles formed by two lines connecting a center of the eccentric pin of the crankshaft and the two contact points, respectively.

9. A horizontal type scroll compressor, comprising:
a motor housing having an inner space for installation of a driving motor therein;
a main scroll coupled to one side of the motor housing to seal the inner space of the motor housing and having a fixed wrap forming compression chambers;
an orbiting scroll having an orbiting wrap engaged with the fixed wrap of the main scroll and coupled to a crankshaft inserted through the main scroll, the orbiting scroll forming a first compression chamber and a second compression chamber on an outer surface and an inner surface of the orbiting wrap while performing an orbiting motion; and
a front housing hermetically coupled to the main scroll, wherein the front housing accommodates the orbiting scroll, and wherein a bearing guide for installation of a main bearing that supports the crankshaft is coupled toward one side surface in an axial direction of the main scroll facing the inner space of the motor housing.

10. The compressor of claim 9, wherein a discharge port is formed toward a surface of the main scroll, the bearing guide being coupled to the surface, and wherein the bearing guide includes a discharge guide portion that accommodates the discharge port therein to guide a refrigerant into the inner space of the motor housing.

11. The compressor of claim 10, wherein the bearing guide includes a guide body formed in an annular shape, and a shaft receiving portion formed through an inner circumferential surface of the guide body, the crankshaft being coupled therethrough, and wherein a discharge passage for a refrigerant is formed between the guide body and the shaft receiving portion, the discharge passage communicating with the discharge port.

12. The compressor of claim 11, wherein the discharge guide portion of the beating guide is formed in plurality on an outer circumferential surface of the guide body to communicate with the discharge passage.