JP2006138217A - Screw compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a lowering in discharge performance caused by intake fluid temperature rise and an increase in a clearance between a rotor and a housing in a screw compressor. <P>SOLUTION: A notch 7c is arranged in the housing 7. The notch 7c is positioned between a high temperature side such as a delivery port 7b, a lubricating oil space 9 and cooling water channels 26, 27 and a low temperature side in the vicinity of a suction opening 7a, and is formed to have a small sectional area in a direction conducting heat from the high temperature side to the low temperature side. Thereby, heat conduction from the high temperature side such as the delivery port 7b to the low temperature side in the vicinity of the suction opening 7a is suppressed. Therefore, intake fluid temperature rise and the increase in the clearance between the rotors 1, 2 and the rotor housing 7 can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a screw compressor that takes in gas from outside, compresses and discharges it, and is suitable as an air supply device having a relatively small compression ratio, for example, used in a fuel cell or the like.

Conventionally, in a screw compressor that operates a pair of rotors with helical teeth in a housing and compresses and discharges gas sucked from the outside, a cooling water flow path is provided in the housing to cool the vicinity of the discharge port What was made to do is known (for example, refer patent document 1).
JP 2003-286852 A

  The above-described conventional screw compressor has a cooling effect in a portion where the temperature is higher than the temperature of the cooling water, such as in the vicinity of the drive transmission unit and the discharge port.

  However, when the outside air temperature is lower than the cooling water temperature, the vicinity of the suction port tends to be lower than the cooling water temperature, but the heat near the discharge port and the heat of the cooling water are transmitted to the vicinity of the suction port through the housing. There has been a problem that the temperature of the entire housing rises, and the discharge performance deteriorates due to the rise of the suction fluid temperature and the increase of the clearance between the rotor and the housing.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress a decrease in discharge performance due to an increase in suction fluid temperature and an increase in clearance between a rotor and a housing in a screw compressor.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a housing (7) having a suction port (7a), a discharge port (7b) and a cooling water flow path (26, 27), and a housing (7). A pair of rotors (1, 2) disposed in the internal space and formed with helical teeth meshing with each other, and gas sucked from the suction port (7a) by rotation of the pair of rotors (1, 2) Transfer of heat from the discharge port (7b) and cooling water flow path (26, 27) side to the suction port (7a) side in the housing (7) in the screw compressor that compresses and discharges from the discharge port (7b) It is characterized by providing a low thermal conduction structure that suppresses the above.

  According to this, since heat conduction to the suction port side is suppressed, an increase in suction fluid temperature and an increase in clearance between the rotor and the housing can be prevented, and a decrease in discharge performance can be suppressed.

  The invention according to claim 2 is characterized in that, in the screw compressor according to claim 1, the low heat conduction structure is a notch (7c) for reducing a cross-sectional area in the heat conduction direction in the housing (7). To do.

  According to this, since the cross-sectional area in the heat conduction direction is reduced and heat conduction to the suction port side is suppressed, the effect of the invention of claim 1 can be obtained. Moreover, since it only provides a notch in a housing, it can implement at low cost.

  Like the invention of Claim 3, the notch (7c) of the screw compressor of Claim 2 can be provided along the helical direction of the teeth of the rotor (1, 2).

  According to a fourth aspect of the present invention, in the screw compressor according to the first aspect, the low heat conduction structure includes a suction side housing (71) on the suction port (7a) side, a discharge port (7b), and a cooling water flow path (26). 27), the housing (7) is divided into the discharge side housing (70), and a heat insulating member (80) having low thermal conductivity is disposed between the suction side housing (71) and the discharge side housing (70). It is characterized by being comprised.

  According to this, since the heat conduction to the suction port side is suppressed by the contact thermal resistance of the divided parts and the heat insulating effect of the heat insulating member, the effect of the invention of claim 1 can be obtained.

  As in the invention described in claim 5, the housing (7) of the screw compressor described in claim 4 can be divided along the spiral direction of the teeth of the rotor (1, 2).

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described. 1 is a conceptual diagram showing a cross-sectional configuration of the screw compressor according to the first embodiment, FIG. 2 is a perspective view of the rotor of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 1, the screw compressor of this embodiment includes a screw-shaped male rotor 1 and a female rotor 2, a rotation transmission mechanism 3 that rotationally drives the rotors 1 and 2 by the rotational force of a drive source, and a pair of rotors 1. 2 and a casing 4 that houses the rotation transmission mechanism 3, an input shaft 5 that receives the rotational force of the drive source, and the like. In FIG. 1, the pair of rotors 1 and 2 are arranged side by side on the back side and the near side.

  The male rotor 1 and the female rotor 2 are rotationally driven by a rotation transmission mechanism 3 that obtains rotational force from a drive source such as an electric motor 100. In the present embodiment, the male rotor 1 is on the driving side and the female rotor 2 is on the driven side, and rotates about the rotation shafts 1a and 2a, respectively.

  As shown in FIGS. 2 and 3, the male rotor 1 and the female rotor 2 are formed in a male screw shape in which a spiral protrusion (tooth) is formed so as to mesh with each other. As shown in FIG. 3, the tooth tip 1 b of the male rotor 1 and the tooth root 2 c of the female rotor 2 mesh with each other, and the tooth root 1 c of the male rotor 1 and the tooth tip 2 b of the female rotor 2 mesh with each other.

  Returning to FIG. 1, the casing 4 includes a lubrication box 6, a rotor housing 7, and a cover 8 in order from the motor 100 side. The lubrication box 6, the rotor housing 7, and the cover 8 are firmly coupled by fastening means such as bolts (not shown). The rotors 1 and 2 and the rotation transmission mechanism 3 are housed in the casing 4 in a state of being separated from each other, the pair of rotors 1 and 2 are housed in the rotor housing 7, and the rotation transmission mechanism 3 is housed in the circulation box 6. Has been.

  In the lubrication box 6, a lubricating oil space 9 in which the rotation transmission mechanism 3 and the lubricating oil supplied to the rotation transmission mechanism 3 are accommodated is formed. As the lubricating oil, for example, an oil having a viscosity comparable to that of engine oil can be used. Lubrication is carried out by splashing the lubricating oil in the lubricating oil space 9 on the gears and the like constituting the rotation transmission mechanism 3.

  The lubrication box 6 is provided with an input shaft 5 that receives a rotational force from the motor 100. The lubrication box 6 is provided with a first bearing 11 on the motor 100 side and a second bearing 12 on the lubricating oil space 9 side. The input shaft 5 is connected to the lubrication box 6 via these bearings 11 and 12. It is supported by. Further, in order to prevent the lubricating oil supplied to the first and second bearings 11 and 12 from flowing out of the casing 4 inside the insertion hole into which the input shaft 5 formed in the lubricating box 6 is inserted. The first oil seal 13 is attached.

  A rotor chamber 10 in which a pair of rotors 1 and 2 are housed is formed in the rotor housing 7. In the rotor housing 7, a suction port 7 a for sucking gas into the rotor chamber 10 and a discharge port 7 b for discharging gas to the outside of the rotor chamber 10 are formed. The suction port 7 a is provided on the cover 8 side of the axial end portion of the rotor housing 7, and the discharge port 7 b is provided on the lubrication box 6 side of the axial end portion of the rotor housing 7.

  A seal structure is formed in which a minute gap is formed between the outer peripheral tips of the rotors 1 and 2 and the inner wall of the rotor chamber 10. A compression chamber 10a for compressing the gas sucked from the suction port 7a is formed between the rotors 1 and 2 and the inner wall of the rotor chamber 10.

  As described above, the rotors 1 and 2 are rotationally driven by the rotation transmission mechanism 3. The rotation transmitting mechanism 3 is configured to transmit the rotation of the input shaft 5 to the male rotor rotating shaft 1a and the female rotor rotating shaft 2a and to rotate the pair of rotors 1 and 2 synchronously. The rotation transmission mechanism 3 is transmitted to the male rotor rotary shaft 1a from the first and second gears 14 and 15 which transmit the rotation of the input shaft 5 driven by the motor 100 to the male rotor rotary shaft 1a. The third and fourth gears 16 and 17 are configured to transmit the rotation to the female rotor rotating shaft 2a. The third and fourth gears 16 and 17 are timing gears for synchronously rotating the pair of rotors 1 and 2.

  One end side of the male rotor rotating shaft 1a and the female rotor rotating shaft 2a is rotatably supported by the rotor housing 7 via the third and fourth bearings 18 and 19, and the other end side is supported via the fifth and sixth bearings 20 and 21. The cover 8 is rotatably supported.

  Further, the lubricating oil supplied to the third and fourth bearings 18 and 19 is prevented from leaking into the rotor chamber 10 in the insertion holes formed in the rotor housing 7 into which the rotor rotation shafts 1a and 2a are inserted. For this purpose, second and third oil seals 22 and 23 are mounted. Further, the grease sealed in the fifth and sixth bearings 20 and 21 is also prevented from leaking into the rotor chamber 10 through the insertion holes formed in the cover 8 into which the rotor rotation shafts 1a and 2a are inserted. The fourth and fifth oil seals 24 and 25 are attached.

  In the rotor housing 7, cooling water passages 26 and 27 through which cooling water flows are formed in order to cool the vicinity of the discharge port 7 b and the lubrication box 6 side, which become high temperature during operation.

  As shown in FIGS. 1 and 3, the outer surface of the rotor housing 7 has a notch 7c along the spiral direction of the teeth of the rotors 1 and 2, in other words, along the twist angle of the teeth of the rotors 1 and 2. Is provided. The notches 7 c are provided in two rows apart in the axial direction of the rotor housing 7. Incidentally, FIG. 3 is a cross-sectional view along the spiral direction of the teeth of the rotors 1 and 2.

  The notch 7c is located between the high temperature side of the discharge port 7b, the lubricating oil space 9, the cooling water passages 26 and 27, and the low temperature side near the suction port 7a, and heats from the high temperature side to the low temperature side. By reducing the cross-sectional area in the direction of conduction, heat transfer from the high temperature side to the low temperature side is suppressed. The notch 7c corresponds to the low heat conduction structure of the present invention.

  Next, the operation of the screw compressor of this embodiment will be described.

  When the pair of rotors 1 and 2 are synchronously rotated by the rotation transmission mechanism 3, gas is sucked into the compression chamber 10a from the suction port 7a provided on the cover 8 side of the rotor housing 7. At this time, the volume of the compression chamber 10a is reduced while moving from the cover 8 side to the lubricating oil space 9 side with the rotation of the pair of rotors 1 and 2, so that the gas in the compression chamber 10a is gradually pressurized. It moves toward the lubricating oil space 9 while being compressed.

  When the rotation angle of the pair of rotors 1 and 2 reaches a predetermined angle, the compression chamber 10a reaches the discharge port 7b provided on the lubricating oil space 9 side of the rotor housing 7, and the compression that has been sealed until then. Since the chamber 10a is opened at the discharge port 7b, the compressed gas in the compression chamber 10a is discharged from the discharge port 7b.

  In the present embodiment, since the cutout 7c is provided, heat conduction from the high temperature side such as the discharge port 7b to the low temperature side near the suction port 7a is suppressed. An increase in the clearance between the housings 7 can be prevented, and a decrease in discharge performance can be suppressed.

  Further, since only the notch 7c is provided in the rotor housing 7, it can be implemented at low cost.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 4 is a conceptual diagram showing a cross-sectional configuration of the screw compressor according to the second embodiment, and FIG. 5 is a cross-sectional view taken along line BB in FIG. In addition, the same code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIGS. 4 and 5, in this embodiment, the rotor housing 7 is divided along the spiral direction of the teeth of the rotors 1 and 2. That is, the rotor housing 7 is divided into a discharge side housing 70 in which the discharge port 7b and the cooling water passages 26 and 27 are formed, and a suction side housing 71 in which the suction port 7a is formed.

  Between the mating surfaces of the discharge side housing 70 and the suction side housing 71, a heat insulating member 80 having a low thermal conductivity such as resin is provided. In addition, the structure which divides | segments into the discharge side housing 70 and the suction | inhalation side housing 71, and arrange | positions the heat insulation member 80 between both the housings 70 and 71 corresponds to the low heat conductive structure of this invention.

  According to the present embodiment, the heat conduction from the high temperature side such as the discharge port 7b to the low temperature side near the suction port 7a is suppressed by the contact thermal resistance of the divided parts and the heat insulation effect of the heat insulating member 80. The rise and the increase in the clearance between the rotors 1 and 2 and the rotor housing 7 can be prevented, and the deterioration of the discharge performance can be suppressed.

(Third embodiment)
A third embodiment of the present invention will be described. FIG. 6 is a conceptual diagram showing a cross-sectional configuration of a screw compressor according to the third embodiment. In addition, the same code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 6, in this embodiment, the rotor housing 7 is divided along the spiral direction of the teeth of the rotors 1 and 2. That is, the rotor housing 7 is divided into a discharge side housing 70 in which the discharge port 7b and the cooling water passages 26 and 27 are formed, and a suction side housing 71 in which the suction port 7a is formed.

  A rubber seal member 90 is provided between the mating surfaces of the discharge side housing 70 and the suction side housing 71. In addition, the structure divided | segmented into the discharge side housing 70 and the suction | inhalation side housing 71 is equivalent to the low heat conductive structure of this invention.

  According to the present embodiment, the heat conduction from the high temperature side such as the discharge port 7b to the low temperature side near the suction port 7a is suppressed by the contact thermal resistance of the divided parts. An increase in the clearance between the rotor housings 7 can be prevented, and a decrease in discharge performance can be suppressed.

It is a key map showing the section composition of the screw compressor concerning a 1st embodiment of the present invention. It is a perspective view of the rotor of FIG. It is sectional drawing which follows the AA line of FIG. It is a conceptual diagram which shows the cross-sectional structure of the screw compressor which concerns on 2nd Embodiment of this invention. It is sectional drawing which follows the BB line of FIG. It is a conceptual diagram which shows the cross-sectional structure of the screw compressor which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... Rotor, 7 ... Housing, 7a ... Inlet port, 7b ... Discharge port, 7c ... Notch, 26, 27 ... Cooling water flow path.

Claims (5)

A housing (7) having a suction port (7a), a discharge port (7b), and a cooling water flow path (26, 27);
A pair of rotors (1, 2) disposed in the internal space of the housing (7) and formed with helical teeth meshing with each other;
In the screw compressor that compresses the gas sucked from the suction port (7a) by the rotation of the pair of rotors (1, 2) and discharges the gas from the discharge port (7b),
The housing (7) is provided with a low heat conduction structure for suppressing heat transfer from the discharge port (7b) and the cooling water flow path (26, 27) side to the suction port (7a) side. Screw compressor to do. The screw compressor according to claim 1, wherein the low heat conduction structure is a notch (7c) that reduces a cross-sectional area of the housing (7) in a heat conduction direction. The screw compressor according to claim 2, wherein the notch (7c) is provided along a spiral direction of teeth of the rotor (1, 2). The low heat conduction structure includes the housing (71) on the suction side housing (71) on the suction port (7a) side, the discharge port (7b), and the discharge side housing (70) on the cooling water flow path (26, 27) side. 7), and a heat insulating member (80) having a low thermal conductivity is arranged between the suction side housing (71) and the discharge side housing (70). The screw compressor according to 1. The screw compressor according to claim 4, wherein the housing (7) is divided along a spiral direction of teeth of the rotor (1, 2).

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