KR20080028173A - Air compressor - Google Patents

Abstract

An air compressor is provided to optimally ensure the suction quantity of air by forming a male rotor and a female rotor having a twist structure such that a volume area defined by the male rotor and the female rotor is changed depending on a twist angle of the male rotor and the female rotor. An air compressor comprises a male rotor(110) axially coupled to a drive shaft(101), a female rotor(120) coupled to a driven shaft(102), a casing(130) and a gear part(160). The casing has a suction port and a discharge port, and forms a compression space of air defined by a rotation of the male rotor and the female rotor. A first end cover(140) and a second end cover(150) close two ends of the casing, respectively. The drive shaft and the driven shaft pass through the first and second end covers on at least one side of the first and second end covers. The male rotor and the female rotor are twisted at a predetermined angle in an axial direction.

Description

Air compressor {AIR COMPRESSOR}

1 is a conceptual diagram illustrating the basic principle of a general air cycle.

2 is a T-s diagram of a typical air cycle

3 is a schematic perspective view of an air compressor according to a conventional example;

4 is a cross-sectional view of an air compressor according to the present invention.

5 is a perspective view of an air compressor according to the present invention, (a) is a front perspective view thereof, (b) is a rear perspective view thereof;

Figure 6 is a perspective view of the coupling of the male rotor and the female rotor in the air compressor according to the present invention.

7 is a perspective view of a male rotor in an air compressor according to the present invention;

8 is a conceptual diagram for explaining the twist angle of the male rotor or the female rotor in the air compressor according to the present invention.

9 is a front sectional view of an air compressor according to the present invention.

10 is a cross-sectional view schematically showing the operation of the air compressor according to the present invention.

11 is a graph showing the relationship of the discharge pressure according to the rotational speed of the air compressor according to the present invention and the conventional air compressor.

<Explanation of symbols for main parts in the drawing>

101: drive shaft 102: driven shaft

110: male rotor 111, 121: convex portion

112, 122: recess 120: female rotor

130: casing 131: inlet

132: discharge port 140,150: first and second end cover

160: gear portion 161: protruding jaw

170: play prevention means 171: T-type bushing

172: coupling member 180: rear cover

O: Oil seal B: Bearing

The present invention relates to an air compressor, and more particularly, an air that can be suitably used as a high speed and high pressure air compressor by significantly increasing the discharge pressure of air and preventing interference and sticking due to fine vibration during high speed rotation. Relates to a compressor.

In general, refrigeration companies around the world are focusing on developing alternative refrigerant systems to replace R134a refrigerants, which have been used to date due to global warming and environmental issues, and are particularly environmentally friendly, safe and efficient, rather than replacing refrigerants themselves. New systems are being studied.

One of the most promising alternative cycles in recent years is an air cycle called a reverse-Bryton cycle, which is a system that uses air as a refrigerant and was developed for the first time as a gas power cycle. This cycle achieves the freezing effect by operating the cycle in reverse.

1 is a conceptual diagram illustrating the basic principle of a general air cycle, and FIG. 2 shows a T-s diagram of a general air cycle.

As shown, the air cycle consists of a compressor (1), an expander (2), a first and second heat exchangers (3, 4), the compression process (1 → 2), the temperature drop process (2 → 3), expansion The cycle is composed through the process (3 → 4) and temperature rise process (4 → 1).

The compression process (1 → 2) is a process in which air is sucked into the compressor 1 so that pressure and temperature are increased through the compression process.

In the temperature lowering process (2 → 3), the compressed high pressure and high temperature air transfers heat to an external heat source through the first heat exchanger 3, and the temperature decreases under the condition of isostatic pressure (actually, a slight pressure drop). In this case, the high temperature heat transferred to the external heat source may be used as a heat source for heating the air conditioning space or obtaining hot water.

In the expansion process (3 → 4), the temperature is lowered by using the expander 2 (similar to the compressor), and the air temperature is lowered to below zero. At this time, the work extracted from the expander (2) can be used as a power for generating electricity or can be returned to the compressor (1) to help the compression work to reduce the power consumption of the compressor (1).

In the temperature increase process (4 → 1), the air having a lowered temperature and pressure passes through the second heat exchanger 4, and the temperature rises. At this time, the air is absorbed from the air-conditioning space and thus serves as a cooling (or freezing) role. Will be performed.

In the above, the efficiency of the air cycle is highly dependent on the efficiency of the compressor 1 and the expander 2. In the past, the efficiency of the two components remained below about 80%, but the overall efficiency of the system was low. The overall efficiency is more than 80% due to the increase in the isentropic efficiency of this part.

In other words, when the efficiency of the compressor 1 is low, the power of the compressor 1 is increased, and the compression temperature is increased (see (1 → 2) in FIG. 2). This is because the cooling capacity decreases because it cannot be obtained (see (3 → 4) in Fig. 2).

Therefore, the coefficient of performance (COP) of the system is greatly changed according to the efficiency of the compressor 1 and the expander 2.

However, in the case of the open type air cycle that directly supplies the cool air to the air conditioning space, the air itself, which is the refrigerant, needs to be breathed, so that contaminated air containing oil, that is, oil, is mixed with pure air. Can not use refrigerant in the air

Oil-free air compressors used in such air cycles include volumetric compressors such as scroll type, screw type, vane rotary type and Roots type, and rotary compressors such as turbo type.

As an example, FIG. 4 schematically shows a Roots type air compressor which is widely used for an oil-free air compressor.

The Roots type air compressor is configured to cause a volume change by causing a volume change by rotating a pair of rotors having two to three blades having a cycloidal curve in opposite directions.

As shown in FIG. 4, the Roots-type air compressor includes a casing 10 having an inlet 11 for air suction and a discharge port 12 for discharging sucked air, and a predetermined inside of the casing 10. The male rotor 13 and the female rotor 14 which are formed to have a predetermined length on the driving shaft and the driven shaft (not shown) which are rotatably assembled at intervals of the interval, and rotate the rotation shaft in opposite directions. Drive means (not shown) such as a motor. Here, the pair of rotors 13 and 14 have a symmetrical structure, and the pair of rotors 13 and 14 are provided on the convex portions 13a and 14a respectively formed in a cycloid curve and on the other rotating shaft. The convex part consists of recessed part 13b, 14b formed by the curve which consists of a contact point which contacts and rotates. Reference numerals 15a and 15b denote shaft holes in which the drive shaft and the driven shaft are provided, respectively.

The air compressor having such a configuration rotates the male rotor 13 and the female rotor 14 while being rotated in opposite directions when the rotating shaft receives rotational force from a motor which is a driving means. As a result, the air sucked through the suction port 11 is compressed at a predetermined rate while passing between the convex portion 13b of the male rotor 13 and the concave portion 14b of the female rotor 14. The discharged air is discharged through the discharge port 12 to configure a cycle.

At this time, in the case of an open type air cycle that directly supplies cool air to an air conditioning space, a human rotor must breathe the air itself, which is a refrigerant, so that contaminated air containing oil other than pure air cannot be used. The convex part 13b of the 13 and the concave part 14b of the arm rotor 14 must be designed in such a way as to minimize clearance between the rotors so that the convex part 13b of the arm rotor 14 does not come into contact with each other. If not maintained, the efficiency of the compressor and expander will be reduced, resulting in reduced system performance and efficiency.

However, in the conventional air compressor, since the pair of rotors 13 and 14 has a linear structure from one end to the other end, there is a problem in that the air suction amount is large but the compression ratio is small and the discharge pressure drops. That is, in order to increase the discharge pressure, there must be a volume change section (a section in which the volume becomes wider and narrower) at the discharging end of the rotor, but the pair of rotors 13 and 14 simply inhale air to force the rotating shaft. Since it has a linear structure which pushes only from the low pressure side to the discharge port on the high pressure side, there is a problem that the compression ratio discharged from the end thereof is low and thus the discharge pressure is low, so that sufficient freezing performance cannot be exhibited.

The convex portion 13b of the male rotor 13 and the concave portion 14b of the female rotor 14 are interfered with each other at high speed by the clearance between the male rotor 13 and the female rotor 14. There is also a problem that the wear caused by the decrease in efficiency due to the temperature rise and the chips generated due to wear stacked in the low pressure side space and stuck.

Due to these problems, the conventional Roots type air compressor is unsuitable as a high speed and high pressure air compressor.

The present invention has been made to solve the above-described problems, and can be suitably used as a high-speed high-pressure air compressor by significantly increasing the discharge pressure of air and preventing interference and sticking due to fine vibrations at high speeds. It is an object to provide an air compressor.

The present invention for achieving this object is a male rotor axially coupled to the drive shaft and consisting of a convex portion and a concave portion having a cycloid curve shape;

An arm rotor axially coupled to a driven shaft so as to be interlocked with the male rotor and having a convex portion and a concave portion having a cycloid curve shape corresponding to the male rotor;

A casing having an inlet and an outlet for intake / discharge of air and forming a compressed space of air by rotation of the male rotor and the female rotor;

The drive shaft and the driven shaft are installed through the axial direction, the first and second end cover for sealing the both ends of the casing, and any one side of the first and second end cover is axially coupled to the drive shaft and the driven shaft, respectively Gear unit for transmitting;

In the air compressor comprising:

The male rotor and the female rotor are characterized in that the structure is twisted at a predetermined twist angle along the axial direction.

Further, in the present invention, the torsion angle of the male rotor and the female rotor is characterized in that it is in the range of 180 ° to 330 °.

In addition, in the present invention, the male rotor and the female rotor is characterized in that the surface treatment with a Teflon coating.

BEST MODE Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a cross-sectional view of the air compressor according to the invention, Figure 5 is a perspective view of the air compressor according to the invention, (a) is a front perspective view thereof, (b) is a rear perspective view thereof, Figure 6 is according to the present invention A combined perspective view of the male rotor and the female rotor in the air compressor, Figure 7 is a perspective view of the male rotor in the air compressor according to the invention, Figure 8 is a structure of the male rotor and the female rotor in the air compressor according to the present invention 9 is a schematic cross-sectional view of a Roots type air compressor according to the present invention, FIG. 10 is a cross-sectional view schematically illustrating an operation process of the air compressor according to the present invention, and FIG. 11 is an air compressor according to the present invention. And a graph showing the relationship between the discharge pressure and the rotational speed of the conventional air compressor.

As shown, the air compressor according to the present invention is a Roots type air compressor, which is a male rotor 110, an arm rotor 120, a casing 130, the first and second end covers 140 and 150 and a gear. The unit 160 is included.

The male rotor 110 is axially coupled to the drive shaft 101, and a convex portion 111 and a concave portion 112 having a cycloid curve shape are formed (see FIG. 7).

The female rotor 120 has a structure symmetrical with the male rotor 110, is axially coupled to the driven shaft 102 to be interlocked with the male rotor 110, the convex portion 111 and the recess 112. Convex portion 121 and concave portion 122 having a cycloid curve shape to correspond to the.

The male rotor 110 and the female rotor 120 each have a key groove 113 on the inner circumferential surface of the shaft holes 101a and 102a so as to be firmly coupled to the driving shaft 101 and the driven shaft 102, respectively. Equipped. Of course, a key (not shown) for inserting into the key groove 113 is formed on the outer circumferential surfaces of the driving shaft 101 and the driven shaft 102.

One end of the drive shaft 101 is connected with a driving means (not shown) for rotating the shaft in a clockwise direction. The driving means may directly connect the shaft of the motor to the driving shaft 101 by using a motor. Or it can be connected using power transmission such as a chain.

Here, since the air compressor according to the present invention is an oil-free air compressor, the convex portion 111 of the male rotor 110 and the concave portion 122 of the female rotor 120, each of the rotors 110 and 120, and a casing are provided. Between 130, between each rotor 110, 120 and the end covers 140, 150 described below, and between each rotor 110, 120, and the front cover / rear cover 180 described below. They are designed to minimize the clearance between each other so that they do not interfere with each other due to micro vibrations at high speed rotation. For example, the spacing is about 0.15 mm or less.

In particular, the male rotor 110 and the female rotor 120 has a structure that is twisted at a predetermined twist angle along the axial direction, respectively, as shown in FIGS. 6 and 7.

The male rotor 110 and the female rotor 120 may be manufactured by variously changing the twist angle according to the shape, position and size of the inlet and outlet of the compressor equipped with all the components. For example, the male rotor 110 and the female rotor 120 preferably have a torsion angle θ in the range of 180 ° to 330 ° in consideration of workability, strength of the material, size of the part, and the like. Since the male rotor 110 and the female rotor 120 have the same structure, FIG. 8 illustrates a torsion angle θ with respect to the male rotor 110, where the angle θ is the maximum angle of 330 °. It is displayed.

When the male rotor 110 and the female rotor 120 are formed in such a structure that both ends thereof are twisted with each other at a predetermined torsion angle, the male rotor 110 and the female rotor 120 interlock with each other by relative rotation. The volume section between the convex portion 111 of the rotor 110 and the convex portion 121 of the female rotor 120 may be changed. Therefore, by changing the volume section, it is possible to ensure the maximum amount of air intake during air intake, and to compress the air sucked at the time of air discharge at the optimum ratio and discharge at the maximum discharge pressure. have.

That is, when the male rotor 110 and the female rotor 120 are continuously rotated in opposite directions in a state in which they are arranged as shown in FIG. 9, as shown in FIG. 4, air introduced from the outside is the male rotor 110. A substantial triangular suction between the convex portion 111 of the arm rotor 120 and the convex portion 121 of the arm rotor 120 (hatched portion of FIG. While passing between the male rotor 110 and the female rotor 120 is transferred to the other end side.

The air thus transported is approximately between the convex portion 111 of the male rotor 110 and the convex portion 121 of the female rotor 120 as described above on the other end side of the male rotor 110 and the female rotor 120. Discharge while passing through a triangular space (in this case, the discharge space), wherein the discharge space is a high pressure while compressing the air transported to the discharge space at the optimum ratio by a repetitive action of increasing the volume and narrowing as opposed to the suction space It is discharged to the outside in a state. As a result of the increase in the discharge pressure, sufficient freezing performance can be exhibited.

The male rotor 110 and the female rotor 120 may use high-strength plastic as their material, or may be made of aluminum and then subjected to Teflon coating having a self-lubricating surface, thereby causing interference due to fine vibration during high-speed rotation. And sticking phenomenon can be prevented beforehand.

On the other hand, the casing 130 forms a compressed space of air by the rotation of the male rotor 110 and the female rotor 120, the outer surface of the inlet 131 for air suction and the discharge port for air discharge ( 132 is formed. Although not shown, the inlet 131 and the outlet 132 are connected to respective ducts.

In FIG. 5, the suction port 131 and the discharge port 132 are illustrated as being formed on one side and the other side of the casing 130, but are not necessarily limited to this position. For example, in order to increase the air compression ratio, the inlet 131 is formed on one side of the casing 130, the outlet 132 is perpendicular to the inlet 131, and the casing 130 is axially formed in the drive shaft 101. It is preferable to form on the front surface of (eg, the front cover described below). In addition, the inlet 131 is formed on the rear surface of the casing 130 in the axial direction of the drive shaft 101 in consideration of the mounting space of the components in the casing 130, and the outlet 132 is perpendicular to the inlet 131. It may be formed on one side of the casing 130 (for example, a rear cover described below). As described above, the suction port 131 and the discharge port 132 have a triangular structure corresponding to the triangular suction space and the discharge space, and the suction port 131 is formed larger than the discharge port 132.

In addition, the first and second end covers 140 and 150 have the driving shaft 101 and the driven shaft 102 penetrated in the axial direction, and seal both ends of the casing 130.

In addition, between the first and second end covers 140 and 150 and the casing 130, an oil seal O for preventing oil from being sucked into the casing 130 is provided in the driving shaft 101 and the driven shaft 102. ) Are combined.

The first and second end covers 140 and 150 are provided with bearings B for supporting the rotation of the drive shaft 101 and the driven shaft 102, respectively, and in particular, the second end cover 150 is provided with bearings. It is preferable that at least two (B) are installed to minimize vibration during the high speed rotation of the drive shaft 101 and the driven shaft 102.

The gear unit 160 is coupled to the drive shaft 101 and the driven shaft 102 to any one side of the first, second end cover 140, 150 to transmit power, in the present invention 1 is installed on the end cover 40 side, the gear portion 160 is made of a helical gear is made to prevent backlash.

On the other hand, on the opposite side of the gear unit 160, the gap prevention for preventing the play between the male rotor 110 and the female rotor 120 disposed between the first and second end cover 140, 150. Means 170 is installed, one side is axially coupled to the center of the male rotor 110 and the female rotor 120, the other side is a pair of T-shaped bushing coupled to the second end cover 150 (171) (only one T-shaped bushing is shown in the drawing), a bearing (B) is axially coupled to the second end cover 150, and one side is in contact with the T-shaped bushing 171, and the bearing (B) is composed of a coupling member 172 for fixing both ends of the drive shaft 101 and the driven shaft 102 coupled to form a constant distance between the gear portion 160 and the first end cover 40 I did it.

In addition, the one side of the gear unit 160, it is preferable that the protruding jaw 161 is formed to contact the inner ring side of the bearing (B) coupled to the first end cover (40).

That is, the driving shaft 101 and the driven shaft 102 with the first end cover 40 are fixed by the protruding jaw 161 of the gear unit 160, and the T-shaped bushing 171 and the bearing ( B) and the male rotor 110 and the female rotor 120 inside the casing 130 are restrained by the play prevention means 170 formed of the coupling member 172, so that play does not occur even if thrust is generated.

Meanwhile, an annular bushing (not shown) is axially coupled on the driving shaft 101 and the driven shaft 102 on the male rotor 110 and the female rotor 120 in contact with the first end cover 40. The play can be further prevented.

In addition, a rear cover 180 is installed outside the gear part 160 to seal the gear part 160, and the drive cover 101 and the driven shaft 102 are attached to the rear cover 180. The bearing B is fixed and the oil seal O is installed in the drive shaft 101 penetrated through the rear cover 180.

As described above, each bearing B supporting the gear unit 160, the drive shaft 101, and the driven shaft 102 by the rear cover 180 can be lubricated with oil, and the oil seal O By blocking the intake of oil to the casing 130 side, only the air in the casing 130 is compressed.

In addition, a front cover (not shown) is installed at the second end cover 150 side.

The operation according to the present invention will be described in detail with reference to FIGS. 9 and 10.

Fig. 9 shows the state seen from the front side of the rear cover, and Fig. 10 shows the state seen from the opposite side.

First, when power is applied to the driving means, the driving shaft 101 rotates at a high speed in a clockwise direction, and at this time, the driven shaft 102 rotates counterclockwise due to the structure engaged with the gear unit 160. And the arm rotor 120 are rotated in the opposite direction to each other. Thereafter, when the male rotor 110 and the female rotor 120 continuously rotate in opposite directions, the air introduced through the wide suction port 131 is convex 111 and the female rotor of the male rotor 110. It is sucked into the suction space between the convex portions 121 of the 120. At this time, the suction space sucks air while causing volume fluctuation (change in the volume section narrowing as the suction space is widened) by continuous rotation of the rotors, and the sucked air is opposite to the suction space, and the male rotor 110 In the process of passing through the discharge space between the convex portion 111 and the convex portion 121 of the arm rotor 120 is compressed at an optimal ratio to discharge the narrow discharge port 132. At this time, the pressure of the discharged air is greatly increased by the volume change of the discharge space (change in the volume section narrowing as the discharge space is widened) according to the continuous rotation of the rotors as in the suction process.

On the other hand, the convex portion 111 of the male rotor 110 and the concave portion 22 of the female rotor 120 during high-speed rotation is not interfered with each other by the play prevention means 170, as well as the thrust does not occur, so wear Etc. does not occur at all.

As described above, the rotor used in the Roots-type air compressor according to the present invention is twisted at a predetermined angle, so that the rotation speed is increased as compared to the linear rotor in the conventional Roots-type air compressor, as shown in FIG. It can be seen that the discharge pressure is significantly improved as the more.

Accordingly, the air compressor according to the present invention can be efficiently used as a high speed and high pressure air compressor while improving the cooling capacity.

Such an air compressor is similar to the components of an air inflator, so that the air compressor of the present invention is sufficiently applicable to an air expander. When the air compressor according to the present invention is used as an air inflator, the discharge port 132 serves as an intake port, and the suction port 131 serves as a discharge port.

As described above, the air compressor according to the present invention has a structure in which the male rotor and the female rotor are twisted at a predetermined angle, thereby causing a large variation in the volume section according to the twist angle at the time of air suction and discharge to maximize the air suction amount. It is possible to increase the discharge pressure significantly while securing it, so that the cooling capacity can be further improved.

In addition, by employing the play prevention means, interference and seizure due to micro-vibration during high speed rotation can be prevented in advance, and thus it can be suitably used as an air compressor of high speed and high pressure.

Claims (3)

A male rotor 110 axially coupled to the drive shaft 101 and having a convex portion 111 and a concave portion 112 having a cycloid curve shape; The female rotor 120 which is axially coupled to the driven shaft 102 so as to be interlocked with the male rotor 110 and has a convex portion 121 and a concave portion 122 having a cycloid curve shape corresponding to the male rotor 110. ; A casing (130) having a suction port (131) and a discharge port (132) for air intake / discharge and forming a compressed space of air by the rotation of the male rotor (110) and the female rotor (120); The drive shaft 101 and the driven shaft 102 are installed through the axial direction, the first and second end covers 140 and 150 sealing both ends of the casing 130, and the first and second end covers. A gear unit 160 axially coupled to the driving shaft 101 and the driven shaft 102 on any one side of the 140 and 150 to transmit power; In the air compressor comprising: The male rotor (110) and the female rotor (120) is an air compressor, characterized in that made of a structure that is twisted at a predetermined twist angle along the axial direction. The method of claim 1, Air compressor, characterized in that the torsion angle of the male rotor (110) and female rotor (120) is in the range of 180 ° ~ 330 °. The method of claim 1, The male rotor (110) and the female rotor (120) is an air compressor, characterized in that the surface treatment with Teflon coating.

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