WO2006033499A1

WO2006033499A1 - Internal gear compression unit and compressor having the same

Info

Publication number: WO2006033499A1
Application number: PCT/KR2004/002498
Authority: WO
Inventors: Kyeong-Ho Kim; Young-Ju Bae; Sam-Chul Ha
Original assignee: Lg Electronics Inc.
Priority date: 2004-09-25
Filing date: 2004-09-25
Publication date: 2006-03-30
Also published as: CN101027487A

Abstract

Disclosed are a compression unit and a compressor having the same. The compression unit comprises: a cylinder block (300) having a gear insertion hole therein; an outer gear (200) having a plurality of inner teeth (250) at an inner circumferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear (100) having a plurality of outer teeth (150) less than the number of the inner teeth (250) of the outer gear (200), inserted into the outer gear (200), and forming a plurality of compression spaces with the inner teeth (250) of the outer gear (200); upper and lower bearings rotatably supporting both ends of the cylinder block in a shaft direction; a suction flow channel (400) formed at the bearing, for supplying fluid to the compression space; a discharge flow channel (500) formed at the bearing, for discharging fluid from the compression space; and a contact supporting means (600) inserted into the cylinder block (300) and contact-supported at an outer circumferential surface of the outer gear (200).

Description

INTERNAL GEAR COMPRESSION UNIT AND COMPRESSOR HAVING THE SAME

Technical Field

[1] The present invention relates to a compression unit and a compressor having the same, and more particularly, to compression unit and a compressor having the same capable of minimizing an excessive contact force unevenly applied to a cylinder that supports a gear in a process for compressing fluid as a volume of a space formed by a contact between two gears is changed.

Background Art

[2] Generally, a compressor is a device for compressing fluid sich as air, refrigerant gas, etc.

[3] The compressor constitutes a refrigerating cycle with an evaporator, a condenser, etc. The refrigerating cycle called as a thermodynamic cycle is for absorbing external heat in a cold reservoir or for emitting heat to outside in a hot reservoir. A system con¬ stituting the refrigerating cycle is called as a refrigerating system, and the refrigerating system is used in a refrigerator, an air conditioner, a heat pump, etc.

[4] The compressor generally includes a motor unit for generating a driving force, and a compression unit for compressing gas by receiving a driving force of the motor unit. As a driving force is generated at the motor unit by an applied power source, the driving force is transmitted to the compression unit and thereby gas is sucked, compressed, and discharged.

[5] The compressor can be divided into a reciprocating compressor, a scroll compressor, a centrifugal compressor, a vane compressor, etc. according to a stricture of the compression unit. Among the above compressors, a gear type compression unit compresses fluid by using a volume change of a space between teeth formed between gears by using a plurality of rotating gears.

[6] Forms of various inner gears of the gear type compression unit have been disclosed in many books (Earle Buckingham, 'Analytical Mechanics of Gears,' McGraw-Hill, 1949, and Dover, 1963; pp. 42-47). Also, a shape of the inner gear has been disclosed in U.S 3, 946, 621.

[7] FIG. 1 is a section view showing one embodiment of a gear type compression unit in accordance with the conventional art. As shown, a rotating inner gear 10 is formed as a doughnut shape, and a driving shaft (not shown) is inserted into an inner circum- ferential surface thereof thus to transmit a driving force. A plurality of outer teeth 15 are formed at an outer circumferential surface of the inner gear 10.

[8] The outer gear 20 is formed as a doughnut shape, and has a space for ac¬ commodating the inner gear 10 at an inner side thereof. An inner teeth 25 is formed at an inner circumferential surface of the outer gear 20 with a larger number than the number of the outer teeth 15 of the inner gear 10, and inserts the outer teeth 15 of the inner gear 10. The center O of the inner gear 10 is separated from the center O of the outer gear 20 with a certain distance.

[9] The outer teeth 15 of the inner gear 10 are respectively in contact with the inner teeth 25 of the outer gear 20, so that a plurality of spaces are formed between the outer teeth 15 and the inner teeth 25.

[10] The outer gear 20 is in a state of being inserted into a cylinder 3D having a gear insertion hole, and an outer circumferential surface of the outer gear 20 is in contact with an inner circumferential surface of the cylinder 3D thereby to be supported. A sectional surface of the gear insertion hole of the cylinder 3D forms a complete circle. It is general to arrange the outer circumferential surface of the outer gear 20 and the inner circumferential surface of the cylinder 3D with a certain clearance by which a rotation of the outer gear is possible and to which oil can be introduced.

[11] An upper bearing and a lower bearing (not shown) for supporting a gear rotation and closing a gear insertion space so as to compress fluid are arranged at both ends of the cylinder 3D in an axial direction.

[12] A suction flow channel 40 for supplying fluid to a space between the teeth 15 of the inner gear 10 and the teeth 25 of the outer gear 20 is formed at an inner portion of the bearing (not shown). The suction flow channel 40 is positioned at a region that a space between the teeth of the outer gear and the inner gear gradually expands. Also, a discharge flow channel 50 for discharging fluid compressed at the space between the teeth of inner gear 10 and the outer gear 20 is formed at the bearing. The discharge flow channel 50 is positioned at a region that the space between the teeth of the outer gear and the inner gear gradually contracts and thereby compressed fluid reaches a proper pressure.

[13] The gear type compression unit compresses fluid by using a volume change of the space formed by the outer teeth 15 of the inner gear 10 and the inner teeth 25 of the outer gear 20 that is rotated with an eccentric state with the inner gear.

[14] Under an assumption that the inner gear is rotated clockwise, an operation of the gear type compression unit will be explained in more detail as follows. [15] When the inner gear 10 is rotated, the outer teeth 15 contacts the inner teeth 25 of the outer gear 20 thus to transmit a driving force, and thereby the outer gear 20 is rotated. The outer circumferential surface of the outer gear 20 is in contact with the inner circumferential surface of the cylinder 3D thus to be supported.

[16] At a region of 180 °~360° in a clockwise direction on the basis of a point A that is the farthest from the center O of the inner gear 10 among an outer circumference of the outer gear 20, a region that a space between the teeth expands is formed. The siction flow channel 40 is formed at the expansion region thereby to sick fluid. Fluid sicked through the siction flow channel 40 moves within the space between the teeth. The space between the teeth of the inner gear 10 and the outer gear 20 contracts in a clockwise direction on the basis of the point A that is the farthest from the center O of the inner gear 10 among the outer circumference of the outer gear 20, and thereby the sicked fluid is gradually compressed. The discharge flow channel 50 is formed at a position that fluid reaches a proper pressure thereby to discharge fluid. While the inner gear 10 is continuously rotated in a clockwise direction, a region that a space between the teeth expands is again formed, and the suction flow channel 40 is formed at the expansion region thereby to sick fluid. The above process is repeated thereby to con¬ secutively compress fluid.

[17] In the process that fluid is compressed, a direction and a size of force applied in a radius direction become different according to a position of the inner gear and the outer gear. Therefore, a position of a contact point between the outer gear and the cylinder and a size of a contact force applied to the contact point are continuously changed.

[18] That is, when the inner gear is located at a specific position during rotation, an excessive contact force is suddenly generated between the outer gear and the cylinder thereby to cause abrasion and overheating of the gear and the cylinder.

[19] The contact force between the gear and the external device is inevitable in the process for compressing fluid. However, an excessive pressure lowers a compression efficiency or wears the teeth of the gear due to a fluid leakage. Also, the excessive pressure causes noise generation and overheating thus to deteriorate lubrication oil.

[20] Therefore, an object of the present invention is to provide a compression unit and a compressor having the same capable of minimizing an excessive contact force unevenly applied to a cylinder that supports a gear in a process for compressing fluid as a volume of a space formed by a contact between two gears is changed.

[21] 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 compression unit comprising: a cylinder block having a gear insertion hole therein; an outer gear having a plurality of inner teeth at an inner circumferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear having a plurality of outer teeth less than the number of the inner teeth of the outer gear, inserted into the outer gear, and forming a plurality of compression spaces with the inner teeth of the outer gear; upper and lower bearings rotatably supporting both ends of the cylinder block in a shaft direction; a siction flow channel formed at the bearing, for supplying fluid to the compression space; a discharge flow channel formed at the bearing, for discharging fluid from the compression space; and a contact supporting means inserted into the cylinder block and contact-supported at an outer circumferential surface of the outer gear.

[22] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided a compressor comprising: a motor unit for rotating a driving shaft by generating a driving force; a compression unit for compressing fluid by receiving a driving force generated from the motor unit and thereby rotating an inner gear and an outer gear; and a contact supporting means inserted into the compression unit, for supporting the outer gear by contacting an outer circumferential surface of the outer gear.

[23] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Description of Drawings

[24] The accompanying drawings, which are included to provide a further un¬ derstanding of the invention and are incorporated in and constitute a part of this spec¬ ification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[25] In the drawings:

[26] FIG. 1 is a sectional view showing one embodiment of a gear type compression unit in accordance with the conventional art;

[27] FIG. 2 is a sectional view showing a gear type compression unit according to one embodiment of the present invention;

[28] FIG. 3 is a graph showing a maximum value of force applied to an outer circum¬ ferential surface of an outer gear according to each position;

[29] FIG. 4 is a sectional view showing a cylinder block according to a second embodiment of the present invention; and

[30] FIG. 5 is a sectional view showing a gear type compression unit according to a second embodiment of the present invention.

Best Mode

[31] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[32] Hereinafter, a compression unit and a compressor having the same will be explained with reference to the attached drawings in more detail.

[33] It is obvious that the compressor can be constituted with the compression unit, and the compressor can be used to devices using a refrigerating system sich as a re¬ frigerator, an air conditioner, a heat pump, etc.

[34] FIG. 2 is a sectional view showing a gear type compression unit according to one embodiment of the present invention.

[35] The compression unit according to the present invention comprises: a cylinder block 200 having a gear insertion hole therein; an outer gear 200 having a plurality of inner teeth 250 at an inner circumferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear 100 having a plurality of outer teeth 150 less than the number of the inner teeth 250 of the outer gear 200, inserted into the outer gear 200, and forming a plurality of compression spaces with the inner teeth 250 of the outer gear 200; upper and lower bearings (not shown) rotatably supporting both ends of the cylinder block in a shaft direction; a siction flow channel 400 formed at the bearing, for supplying fluid to the compression space; a discharge flow channel 500 formed at the bearing, for discharging fluid from the compression space; and a contact supporting means 600 inserted into the cylinder block 300 and contact-supported at an outer circumferential surface of the outer gear 200.

[36] The inner gear 100 is formed as a doughnut shape, and is rotated by being coupled to a driving shaft (not shown) for transmitting a driving force generated from a motor unit. In the preferred embodiment, the number of the outer teeth 150 of the inner gear 100 is 6. However, the number of the outer teeth 150 of the inner gear 100 can be various if the number thereof is less than the number of the inner teeth 250 of the outer gear 200. The shape of the outer teeth 150 of the inner gear 100 can be various. However, the outer teeth 150 of the inner gear 100 preferably has a shape of a cycloid curve.

[37] The outer gear 200 is formed as a doughnut shape, and has the inner teeth 250 at the inner circumferential surface thereof into which the outer teeth 150 of the inner gear 100 is inserted. In the preferred embodiment, the number of the inner teeth 250 of the outer gear 200 is 7 that is more than the number of the outer teeth 150 of the inner gear 100. As the inner gear 100 is rotated, the outer gear 200 receives the driving force thereby to be rotated together. The outer gear 200 can be constricted not to be rotated. In case that the inner gear 100 and the outer gear 200 are rotated together, a balance of torque is maintained thereby to redice vibration and noise. Especially, since the plurality of outer teeth 150 and the inner teeth 250 are in contact with one another, force generated from inside is not concentrated but spreads. Also, in case that the inner gear 100 and the outer gear 200 are rotated together, the structure is simplified.

[38] As the outer teeth 150 of the inner gear 100 and the inner teeth 250 of the outer gear 200 are in contact with one another, a plurality of spaces are formed between the outer teeth 150 and the inner teeth 250. The center O of the inner gear 100 is separated from the center O of the outer gear 200 with a certain distance.

[39] The cylinder block 300 is formed as a cylindrical shape, and has a gear insertion space into which the outer gear 200 is inserted at one side thereof. A contact supporting means insertion space connected to the gear insertion space and into which the contact supporting means 600 is inserted is formed at the cylinder block 300.

[40] A shape of the inner teeth 250 can be various. However, it is preferable that the inner teeth 250 is formed as three circular arcs having different curvatures are combined one another.

[41] The cylinder block 300 has a space for accommodating the outer gear 200. The space for accommodating the outer gear 200 has a sectional surface of a circle shape, has a diameter somewhat larger than a diameter of the outer gear 200, and has a clearance into which oil can be introduced.

[42] Upper and lower bearings for supporting the gear rotation and closing the gear insertion space so as to compress fluid are arranged at both ends of the cylinder block 300 in a shaft direction.

[43] The suction flow channel 400 is formed at the bearing, and supplies fluid to a space between the outer teeth 150 of the inner gear 100 and the inner teeth 250 of the outer gear 200.

[44] The suction flow channel 400 is positioned at a region that the space between teeth of the inner gear 100 and the outer gear 200 gradually expands. That is, under an assumption that the inner gear 100 is rotated in a clockwise direction, the space between the teeth of the inner gear and the outer gear expands at a region of 0 °~180° in a counterclockwise direction on the basis of a point A that is the farthest from the center O of the inner gear 10 among an outer circumference of the outer gear 20 . According to this, the siction flow channel 400 is preferably formed at the expansion region. In the expansion region that the hermetic space between the teeth of the inner gear and the outer gear expands, a pressure is lowered and a fluid siction is smoothly performed.

[45] The discharge flow channel 500 is formed at the bearing, and discharges compressed fluid. The discharge flow channel is preferably located at a position that the space between the teeth of the inner gear and the outer gear contracts and thereby compressed fluid reaches a proper pressure.

[46] The contact supporting means 600 can be formed as a cylindrical shape having a certain height and diameter thus to be in line-contact with the outer circumferential surface of the outer gear 200. The contact supporting means 600 is inserted into the cylinder block 300, and the outer circumferential surface thereof is in contact with the outer circumferential surface of the outer gear 200 at a contact point B thus to be supported.

[47] The contact supporting means 600 can be formed as a sphere shape thus to be in point-contact with the outer circumferential surface of the outer gear 200. The contact supporting means 600 can be filled with a plurality of balls of a sphere shape thus to have a plurality of contact points to the outer circumferential surface of the outer gear 200.

[48] At this time, it is preferable that the contact supporting means 600 is protruded towards the outer gear 200 within a range of being smaller than the clearance between the outer circumference of the outer gear 200 and the inner circumference of the cylinder block 300 thereby to be in contact with the outer gear 200. If the contact supporting means 600 is excessively protruded towards the outer gear 200, un¬ necessary friction and abrasion are caused. Also, if the contact supporting means 600 is protruded towards the outer gear 200 too little, there is no meaning to install the contact supporting means 600. According to this, the contact supporting means is protruded within a range of being smaller than the clearance between the outer cir¬ cumference of the outer gear 200 and the inner circumference of the cylinder block 300, and thus to be in contact with the outer gear 200.

[49] The contact supporting means 600 is preferably located at a position where an op¬ erational force between the outer gear 200 and the cylinder block 300 is minimum. The operational force can be obtained by adding a contact force between the inner gear 100 and the outer gear 200 to a support force between the outer gear 200 and the cylinder block 3DO. That is, the contact point B between the contact supporting means 600 and the outer gear 200 is preferably located at a position where the minimum operational force is applied in a state that the contact supporting means 600 is not installed. At the contact point B, the contact supporting means 600 and the outer gear 200 are in contact with each other continuously. That is, the contact supporting means 600 is inserted into the cylinder block 3D0 so as to in contact with the outer gear 200 at a position where the minimum operational force is applied, thereby supporting the outer gear 200.

[50] The position where the minimum operational force is applied is mainly a region that a suction operation of fluid is performed, which is a region corresponding to 0 °~180° in a counterclockwise direction on the basis of the A point.

[51] FIG. 3 is a graph showing a maximum value of force applied to an outer circum¬ ferential surface of the outer gear according to each position.

[52] The horizontal axis of the graph shows angles measured at each position of the outer circumferential surface of the outer gear 200 in a counterclockwise direction on the basis of the point A that is the farthest from the center Ol of the inner gear 100. Also, the vertical axis of the graph shows a sum between a maximum value of a contact force between the inner gear 100 and the outer gear 200 and a maximum value of a support force between the outer gear 200 and the cylinder block 3D0. The contact force and the support fore are instantaneously changed as the gear is rotated, so that the maximum values thereof are shown at the vertical axis of the graph.

[53] As shown, the contact force between the inner gear 100 and the outer gear 200 is relatively constant as less force at 45 °~135°. On the contrary, the support force between the outer gear 200 and the cylinder block 3D0 is less at 120 °~150°. According to this, the sum between the contact force and the support force is the least at 120 °~150°, and thereby the contact supporting means 600 is preferably inserted at 120 °~150°.

[54] In case that the inner gear 100 is rotated in a clockwise direction like in the preferred embodiment, the contact supporting means 600 is preferably positioned at 120 °~150° in a counterclockwise direction on the basis of a point that is the farthest from the center O of the inner gear 100 among the outer circumference of the outer gear 200. However, in case that the inner gear 100 is rotated in a counterclockwise direction, the contact supporting means 600 is preferably positioned at 120 °~150° in a clockwise direction on the basis of a point that is the farthest from the center O of the inner gear 100 among the outer circumference of the outer gear 200.

[55] FIG. 4 is a sectional view showing a cylinder block according to a second embodiment of the present invention, and FIG. 5 is a sectional view showing a gear type compression unit according to a second embodiment of the present invention.

[56] As shown, an inner circumference of the cylinder block 3D0 has two different radiuses. In the preferred embodiment, two different radiuses are defined as RD and R31. However, the radius can be variously implemented.

[57] It is preferable that a contact point between the contact supporting means 600 and the outer gear 200 is positioned at the inner circumference of the cylinder block 300 having a larger radius. That is, in order to maintain more continuous contact between the outer gear 200 and the contact supporting means 600 inserted into the cylinder block 3D0, the outer gear 200 is moved towards the contact supporting means 600. According to this, the outer gear 200 can be in contact with the cylinder block 3D0 more frequently.

[58] It is obvious that the compressor having the aforementioned compression unit can be constricted.

[59] A compressor generally includes a motor unit for generating a driving force, and a compression unit for compressing gas by receiving a driving force of the motor unit. As a driving force is generated at the motor unit by an applied power source, the driving force is transmitted to the compression unit and thereby gas is sucked, compressed, and discharged.

[60] The compression unit includes: a cylinder block 3D0 having a gear insertion hole therein; an outer gear 200 having a plurality of inner teeth 250 at an inner circum¬ ferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear 100 having a plurality of outer teeth 150 less than the number of the inner teeth 250 of the outer gear 200, inserted into the outer gear 200, and forming a plurality of compression spaces with the inner teeth 250 of the outer gear 200; upper and lower bearings rotatably supporting both ends of the cylinder block 3D0 in a shaft direction; a siction flow channel 400 formed at the bearing, for supplying fluid to the compression space; a discharge flow channel 500 formed at the bearing, for discharging fluid from the compression space; and a contact supporting means 600 inserted into the cylinder block 3D0 and contact-supported at an outer circumferential surface of the outer gear 200.

[61] Hereinafter, an operation and an effect of the present invention will be explained as follows.

[62] When the inner gear 100 is rotated in order to compress fluid, the outer gear 200 that has received the driving force is rotated, and the outer circumferential surface of the outer gear 200 is in contact with the inner circumferential surface of the cylinder block 3D0 thus to be supported. In the conventional art, in the process that fluid is compressed, a direction and a size of force applied in a radius direction become different according to a position of the inner gear 100 and the outer gear 200. Therefore, a position of a contact point between the outer gear 200 and the cylinder block 3D0 and a size of a contact force applied to the contact point are continuously changed.

[63] However, in the present invention, the contact supporting means 600 maintains the contact with the outer gear 200 at the contact point B, thereby continuously contact- supporting the outer gear 200. According to this, the contact between the contact supporting means 600 and the outer gear 200 is restricted at the outer circumferential surface of the outer gear 200 except the contact point B. Since the contact supporting means 600 is positioned between the outer gear 200 and the cylinder block 3D0 where the minimum force is applied, the contact supporting means 600 can support the outer gear 200 with the minimum force.

Industrial Applicability

[64] In the compression unit and the compressor having the same, the contact supporting means is inserted into the cylinder block at a position where the minimum contact force is applied thus to fix a contact point between the outer gear and the cylinder block, thereby supporting the outer gear with less contact force.

[65] That is, since the contact supporting means 600 and the outer gear 200 are in contact with each other only at the contact point B, an excessive contact force between the outer gear 200 and the cylinder block 3D0 that may be generated at a specific position during a compression process of fluid can be prevented. According to this, abrasion and overheating of the gear and the cylinder block can be prevented.

[66] Also, since abrasion and damage of the teeth of the gear can be prevented, lowering of a compression efficiency due to a fluid leakage, noise generation, and lu¬ brication oil deterioration due to overheating can be prevented.

[67] Also, in the compression unit and the compressor having the same, an excessive contact force between the outer gear and the cylinder block that may be generated at a specific position during a compression process of fluid can be prevented. According to this, abrasion and overheating of the gear and the cylinder block can be prevented.

[68] Additionally, in the compression unit and the compressor having the same, since abrasion and damage of the teeth of the gear can be prevented, lowering of a compression efficiency due to a fluid leakage, noise generation, and lubrication oil de- terioration due to overheating can be prevented.

[69] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above- described embodiments are not limited by any of the details of the foregoing de¬ scription, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modi¬ fications that fall within the metes and bounds of the claims, or equivalence of sich metes and bounds are therefore intended to be embraced by the appended claims.

Claims

[ 1 ] A oompres sion unit comprising : a cylinder block having a gear insertion hole therein; an outer gear having a plurality of inner teeth at an inner circumferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear having a plurality of outer teeth less than the number of the inner teeth of the outer gear, inserted into the outer gear, and forming a plurality of compression spaces with the inner teeth of the outer gear; upper and lower bearings rotatably supporting both ends of the cylinder block in a shaft direction; a siction flow channel formed at the bearing, for supplying fluid to the compression space; a discharge flow channel formed at the bearing, for discharging fluid from the compression space; and a contact supporting means inserted into the cylinder block and contact- supported at an outer circumferential surface of the outer gear.

[2] The compression unit of claim 1, wherein the number of the outer teeth of the inner gear is 6, and the number of the inner teeth of the outer gear is 7.

[3] The compression unit of claim 1, wherein the cylinder block has a gear insertion space for inserting a gear therein, and has a contact supporting means insertion space connected to the gear insertion space for accommodating the contact supporting means.

[4] The compression unit of claim 1, wherein the cylinder block has an inner cir¬ cumference composed of two different radiuses.

[5] The compression unit of claim 1, wherein a contact point between the contact supporting means and the outer gear is positioned at the inner circumference of the cylinder block having a larger radius.

[6] The compression unit of claim 1, wherein the contact supporting means is a ball.

[7] The compression unit of claim 1, wherein the contact supporting means is a plurality of balls.

[8] The compression unit of claim 1, wherein the contact supporting means is a cylinder having a certain height and diameter.

[9] The compression unit of claim 1, wherein the contact supporting means is located at a position between the outer gear and the cylinder block where an operation force is minimum.

[10] The compression unit of claim 2, wherein the contact supporting means is positioned at 120°~150° in a counterclockwise direction on the basis of a point that is the farthest from a center of the inner gear among an outer circumference of the outer gear.

[11] The compression unit of claim 2, wherein the contact supporting means is positioned at 120 °~150° in a clockwise direction on the basis of a point that is the farthest from a center of the inner gear among an outer circumference of the outer gear.

[12] The compression unit of claim 1, wherein the contact supporting means is protruded to the outer gear within a range of being smaller than a clearance between an outer circumference of the outer gear and an inner circumference of the cylinder block thereby to be in contact with the outer gear.

[13] A compressor comprising: a motor unit for rotating a driving shaft by generating a driving force; a compression unit for compressing fluid by receiving a driving force generated from the motor unit and thereby rotating an inner gear and an outer gear; and a contact supporting means inserted into the compression unit, for supporting the outer gear by contacting an outer circumferential surface of the outer gear.

[14] The compressor of claim 13, wherein the compression unit includes: a cylinder block having a gear insertion hole therein; an outer gear having a plurality of inner teeth at an inner circumferential surface thereof, and rotatably inserted into the gear insertion hole; an inner gear having a plurality of outer teeth less than the number of the inner teeth of the outer gear, inserted into the outer gear, and forming a plurality of compression spaces with the inner teeth of the outer gear; upper and lower bearings rotatably supporting both ends of the cylinder block in a shaft direction; a siction flow channel formed at the bearing, for supplying fluid to the compression space; a discharge flow channel formed at the bearing, for discharging fluid from the compression space; and a contact supporting means inserted into the cylinder block and contact- supported at an outer circumferential surface of the outer gear.