VANE PUMP

Abstract: A vane pump having a vane (25) integrally formed with either drive rotor (23) or driven rotor (27) and thereby free from abrasion and damage of the vane is disclosed. The pump also has an operation cavity (26) formed in either the drive rotor (23) or driven rotor (27) and thereby making smooth vane rotation and achieving desired sealing effect of the pump. In an embodiment, the vane pump has a hollow cylindrical drive rotor rotatable about a drive shaft between a front housing (21) and a rear housing (22). A driven rotor (27) is rotatably received in the cylindrical space (26) of the drive rotor (23) and rotatable about an eccentric shaft (28). The vane (23) integrally extends from an inner wall of the drive rotor (23) while the operation cavity (29) with a seal (31) is formed in the drive rotor (27) and airtightly receives the vane (25).

Description: VANE PUMP Technical Field The present invention relates in general to vane pumps and, more particularly, to a structural improvement in such vane pumps for achieving high speed rotation, high compression force and large pump delivery of the vane pump by placing a small diameter driven rotor in a cylindrical inside space of a drive rotor and by letting the driven rotor rotate along with the drive rotor due to a vane of the drive rotor. Background Art As well known to those skilled in the art, a typical vane pump includes an eccentric rotor which is placed in a cylinder and eccentrically rotates in the cylinder by the rotational force of an eccentric drive shaft. At least one vane is radially located in the eccentric rotor and biased outward by a compression coil spring such that the vane elastically radially reciprocates during eccentric rotation of the rotor in the cylinder. Therefore, the spring-biased vane of the typical vane pump elastically reciprocates and rotates along with the rotor while contacting, at its tip, with the inner wall of the cylinder and thereby compressing the fluid, such as oil or air, sucked into the cylinder through a suction port of the cylinder. The compressed fluid or the pressurized fluid in turn is discharged from the cylinder through an exhaust port of the cylinder. That is, the gap between the eccentric rotor and the inner wall of the cylinder of the typical vane pump continuously varies due to eccentric rotation of the rotor in the cylinder so that the spring-biased vane elastically repeatedly protrudes and retracts while contacting with the inner wall of the cylinder. In this regard, the protruding vane contacting with the inner wall of the cylinder may be seriously damaged when the eccentric rotor rotates in the cylinder at high speed. Therefore, the rotor of typical vane pump can not help being limited in its rotational speed and the vane can not help being limited in its material and in its size. With reference to Fig. 1, there is shown a typical gear pump in a sectional view. As shown in this drawing, the typical gear pump includes an outer rotor 1 and an inner rotor 3. The outer rotor 1 is provided with internal gears 2 while the inner rotor 3 is provided with external gears 4. The number of external gears 4 of the inner rotor 3 is less than the number of internal gears 2 of the outer rotor 1 by one so that the rotors 1 and 3 relatively rotate while keeping one point contact between their gears 2 and 4. In the above gear pump, the outer and inner rotors 1 and 3, which have their gears 2 and 4 functioning as vanes of typical vane pump, rotate about their drive shafts and somewhat stably compress the fluid, sucked into the space between the rotors 1 and 3 through a suction port 5, prior to discharging of the compressed fluid from the pump through an exhaust port 6.. Nevertheless, there is a limit in sealing effect of the above gear pump so that the gear pump can not be used for compression of gaseous fluid. Another problem of the gear pump is resided in that the pump inevitably wastes power for unit pump delivery. Turning to Figs. 2A to 2C, there is shown a typical rotary compressor disclosed in Japanese Patent Laid-open Publication No. 93-215087. As shown in the drawings, the rotary compressor includes a cylindrical inner rotor 10, which has a radial slit 11 and is eccentrically placed in a cylindrical outer rotor 12 such that the inner rotor 10 contacts with the inner wall of the outer rotor 12. A blade 14 is held in a blade cavity 13 of the outer rotor 12 and radially inwardly extends such that the blade 14 is received and radially slides in the slit 11 of the inner rotor 10. After assembling the inner and outer rotors 10 and 12 with the blade 14 into a rotor assembly, the rotor assembly is received in a cylinder 15. When either of the two rotors 10 and 12 in this state is applied with rotational force so as to rotate, there is formed both an exhaust chamber (or a compression chamber) and a suction chamber in a sealed space defined by the rotors 10 and 12 and the blade 14 of the compressor. That is, the exhaust chamber is defined in front of the blade 14 while the suction chamber is defined in back of the blade 14. However, the above rotary compressor is noted to have the following problems. First, the blade 14 is applied with both compression force from the front and vacuum force from the back in accordance with advance of the blade 14 so that a pressure frictional damage is generated in the slit 11 of the inner rotor 10 and in the blade cavity 13 of the outer rotor 12. In operation of the above compressor, the inward setting of the blade 14 in the slit 11 is increased in proportion to both the rotational speed of the rotor and the pressure. Second, there is generated a frictional abrasion in the blade cavity 13 of the outer rotor 12 due to frictional contact of the blade 14 with the cavity 13. The frictional abrasion of the blade cavity 13 becomes worse due to the fact that the blade 14 is designed to play at 17° angles in leftward and rightward directions during one rotation of the blade 14 received in the slit 11 of the inner rotor 10. Therefore, the blade 14 may be suddenly separated from the cavity 13 during operation of the compressor. Third, as the cylinder 15 contacting with the outer surface of the outer rotor 12 is provided with both suction chamber 16 and exhaust chamber 17, both the compression force of the compressed air filled in the exhaust chamber 17 and the compression force generated in a compression chamber A forcibly bias both a right side housing 18 and a left side housing 19. In this regard, there may be generated deformation and distortion in the side housings 18 and 19. Disclosure of Invention It is, therefore, an object of the present invention to provide a vane pump in which the above problems of the typical pumps and typical compressors are overcome and whose vane is integrally formed with either drive rotor or driven rotor and thereby free from abrasion and damage. It is another object of the present invention to provide a vane pump which is provided with an operation cavity formed in either the drive rotor or driven rotor and thereby making smooth vane rotation and achieving desired sealing effect of the pump. In order to accomplish the above objects, a vane pump of an embodiment of the present invention includes a hollow cylindrical drive rotor rotatable about a drive shaft between a front housing and a rear housing; a driven rotor rotatably received in the cylindrical space of the drive rotor and rotatable about an eccentric shaft; a vane integrally extending from an inner wall of the drive rotor; an operation cavity formed in the driven rotor and airtightly receiving the vane by a seal, whereby the pump compresses the fluid during eccentric rotation of the driven rotor. In another embodiment, the vane is formed in the driven rotor while the operation cavity is formed in the drive rotor and engages with the vane, thus to let the pump compress the fluid during eccentric rotation. In still another embodiment, a first vane and a first operation cavity are formed in opposed portions of the driven rotor while a second operation cavity and a second vane are formed in opposed portions of the drive rotor and engage with the first vane and the first cavity respectively, thus to let the pump carry out fluid compression process more repeatedly and to reduce the driven rotor size and to increase the fluid compression capacity per unit size of the driven rotor. The vane pump of this invention lets smooth vane operation and is free from frictional abrasion and damage of the vane and improves the compression efficiency. Brief Description of Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a cross sectioned view showing a construction of a typical gear pump; Figs. 2A to 2C are views showing a construction of a typical rotary compressor; Figs. 3 and 4 are cross sectioned views showing operation of a vane pump in accordance with a primary embodiment of the present invention; Fig. 5 is a longitudinally sectioned view of the vane pump of Fig. 3; Fig. 6 is a cross sectioned view of a vane pump in accordance with a second embodiment of the present invention; Fig. 7 is a cross sectioned view of a vane pump in accordance with a third embodiment of the present invention; Fig. 8 is a longitudinally sectioned view of the vane pump of Fig. 7; Fig. 9 is a longitudinally sectioned view of another embodiment of the vane pump of Fig. 7; Fig. 10 is a cross sectioned view of a vane pump in accordance with a fourth embodiment of the present invention; Fig. 11 is a longitudinally sectioned view of the vane pump taken along the section line A-A of Fig. 10; Figs. 12 and 13 are cross sectioned views showing operation of a vane pump in accordance with a fifth embodiment of the present invention; and Fig. 14 is a longitudinally sectioned view of the vane pump of Fig. 13. Best Mode for Carrying Out the Invention Referring first to Figs. 3 to 5, there are shown construction and operation of a vane pump in accordance with a primary embodiment of the present invention. As shown in the drawings, the vane pump includes a drive rotor 23 which rotates about a drive shaft 24 between a front housing 21 and a rear housing 22. A vane 25 integrally radially extends from the inner wall of the drive rotor 23. The vane pump also includes a driven rotor 27- which is received in the cylindrical space 26 of the drive rotor 23 such that it can rotate about an eccentric shaft 28. A generally cylindrical operation cavity 29 having both a flat bottom 29a and opposed curved walls 29b is formed in the drive rotor 27. The operation cavity 29 is provided, at its inlet, with a pair of spring-biased seals 31 so that a vane 25 is airtightly received in the cavity 29. The seals 31 are biased by their springs 30. In the above vane pump, the fluid, such as air or oil, sucked into the chamber defined between the rotors 23 and 27 through a suction port 32 is compressed and, thereafter, discharged from the chamber through an exhaust port 33 provided with a check valve (not shown). In operation of the above vane pump, the fluid is sucked into the chamber through the suction port 32 when the rotors 23 and 27 are relatively located as shown in Fig. 3. The drive rotor 23 rotates in the direction of arrow of Fig. 3 by outside rotational force transmitted thereto through the drive shaft 24. Fluid compression of the vane pump starts just after the vane 25 passes by the suction port 32. That is, the vane 25 integrally formed with the drive rotor 23 rotates along with the drive rotor 23 under the condition that the vane 25 is airtightly received in the operation cavity 29 by the spring-biased seals 31. Therefore, the drive rotor 27, which is received in the space 26 of the drive rotor 23 and fixed to the eccentric shaft 28, rotates along with the drive rotor 23. Even though the vane 25 is somewhat slanted in accordance with rotation of the drive rotor 23, the vane 25 stably rotates while keeping the stable engagement with the operation cavity 29 due to the opposed curved walls 29b of the cavity 29. As the compression chamber defined by the drive rotor 23, the vane 25 and the driven rotor 27 moves in the direction toward the exhaust port 33 as shown in Fig. 4, the chamber size is gradually reduced so that the fluid in the chamber is compressed prior to discharging through the exhaust port 33. As the exhaust port 33 is provided with the check valve or a unidirectional valve, the compressed fluid does not inversely flow but is discharged from the compression chamber without failure. Turning to Fig. 6, there is shown a vane pump in accordance with a second embodiment of the present invention. In the second embodiment, a driven rotor 41 is rotatably received in a housing 40. The driven rotor 41 is provided with an operation cavity 43 having both a flat bottom 43a and opposed curved walls 43b. The operation cavity 43 is also provided, at its inlet, with a pair of spring-biased seals 42. A drive rotor 47 is received in the cylindrical space 46 of the driven rotor 41 and rotates by outside rotational force transmitted thereto through a drive shaft 48. The drive rotor 47 is provided with an integral vane 49, which is airtightly received in the cavity 43 due to the seals 42. The driven rotor 41 thus rotates along with the drive rotor 47. In operation of this vane pump, the fluid sucked into the chamber through a suction port 32 is compressed and, thereafter, discharged from the chamber through an exhaust port 33. Referring next to Figs. 7 and 8, there is shown a vane pump in accordance with a third embodiment of the present invention. In the third embodiment, a driven rotor 51 which is rotatably received in a housing 50 is provided with a first operation cavity 53 having both a flat bottom 53a and opposed curved walls 53b in the same manner as described for the second embodiment. The operation cavity 53 is provided, at its inlet, with a pair of spring-biased seals 52. The driven rotor 51 is also provided with a vane holding cavity 54 at a portion opposed to the cavity 52. In the holding cavity 54, a vane 54a is pivoted to the cavity 54 by means of a bolt 54b such that the vane 54a extends radially inwardly from the driven rotor 51. A drive rotor 56, which is received in the cylindrical space 55 of the driven rotor 51 and rotates by outside rotational force transmitted thereto through a drive shaft 57, is provided with an integral vane 58 which is airtightly received in the cavity 53 due to the seals 52. The drive rotor 56 is also provided with a second operation cavity 60 at a portion opposed to the integral vane 58. The second operation cavity 60 for airtightly receiving the vane 54a has both a flat bottom 60a and opposed curved walls 60b and is provided, at its inlet, with a pair of spring-biased seals 59. With the vanes 58 and 54a, the vane pump of the third embodiment carries out more repeated compression processes. In the third embodiment, the vane 54a bolted to the cavity 54 is scarcely abraded or damaged during the compression process of the pump as the playing angle of the vane 54a is reduced. Fig. 9 is a longitudinally sectioned view of another embodiment of the vane pump of Figs. 7 and 8. In the embodiment of Fig. 9, a drive rotor 61 is rotatably received in a housing 50 and rotates by outside rotational force transmitted thereto through a drive shaft 62. A driven rotor 64 is received in the cylindrical space 63 of the drive rotor 61 and rotates about its shaft 65. In this embodiment, a first vane 61a of the drive rotor 61 is airtightly received in a first operation cavity 64a of the driven rotor 64 while a second vane 64b of the driven rotor 64 is airtightly received in a second operation cavity 61b of the drive rotor 61. Figs. 10 and 11 show a vane pump in accordance with a fourth embodiment of the present invention. In the fourth embodiment, a drive rotor 71 is rotatably received in a housing 70 and rotates by outside rotational force transmitted thereto through a drive shaft 72. A vane 73 integrally extends from the inner wall of the drive rotor 71 having the cylindrical space 74. The vane pump of the fourth embodiment also includes a driven rotor 75. The driven rotor 75 is placed in the space 74 of the drive rotor 71 and eccentrically rotates about an eccentric shaft 76 in the drive rotor 71. The driven rotor 75 has a cavity 77 which is provided with an opening 78 for receiving the integral vane 73 of the drive rotor 71. The driven rotor 75 thus rotates even by lower force when the drive rotor 71 rotates by the outside rotational force. In addition, as the vane 73 of the drive rotor 71 may be lengthened such that the vane 73 reaches the cavity 77 of the drive rotor 75, the pump may have larger compression chamber defined by the inner wall of the drive rotor 71, the outer wall of the driven rotor 75 and the vane 73 and thereby having larger pump delivery. Figs. 12 to 14 show a vane pump in accordance with a fifth embodiment of the present invention. In the fifth embodiment, a drive rotor 83 rotates about a drive shaft 84 between a front housing 81 and a rear housing 82. A vane 85 integrally radially extends from the inner wall of the drive rotor 83. A driven rotor 87 is received in the cylindrical space 86 of the drive rotor 83 and rotates about its eccentric shaft 88. The driven rotor 87 is provided with a cylindrical cavity 89 for receiving a rotor body 90. The rotor body 90 has a slit 91 for receiving the vane 85 of the drive rotor 83 and rotates in the cavity 89 in accordance with rotation of the vane 85. In operation of the vane pump of the fifth embodiment, the fluid such as air or oil sucked into the chamber through a suction port 92 is compressed and, thereafter, discharged from the chamber through an exhaust port 93 provided with a check valve (not shown). In the vane pump of the fifth embodiment, both the rotor body 90 receiving the vane 85 in its slit 91 and the driven rotor 87 rotate about the eccentric shaft 88 in accordance with rotation of the vane 85 integrally formed with the drive rotor 83. In order to prevent possible slanting of the vane 85 and the rotor body 90 during rotation of both the rotor body 90 and the driven rotor 87, the rotor body 90 optionally turns in a direction in the cavity 89 of the driven rotor 87. It is, therefore, possible to keep the stable engagement of the vane 85 with the slit 91 of the rotor body 90 and to prevent possible fluid leakage. Industrial Applicability As described above, the vane pump of the present invention has a simple construction including a drive rotor, a driven rotor, a vane and an operation cavity and thereby saving the cost and simplifying the production process. As the vane rotates along with the rotors under the condition that the vane is received in the operation cavity, the rotors can rotate at high speed and achieve high pressure and compression of large amount of fluid. In the vane pump of this invention, the vane is integrally formed with either the drive rotor or the driven rotor and is airtightly received in the operation cavity so that the vane achieves stable operation and is free from frictional abrasion and damage. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims: What is claimed is: 1. A vane pump having a drive rotor received in a housing and an eccentric driven rotor received in the drive rotor and compressing fluid sucked into a chamber defined between the rotors through a suction port and discharging the fluid from the chamber through an exhaust port, wherein the improvement comprises: a vane integrally extending from an inner wall of the drive rotor rotated about a drive shaft; and an operation cavity for airtightly receiving said vane, said operation cavity being formed in the driven rotor rotatably received in a cylindrical space of said drive rotor. 2. The vane pump according to claim 1, wherein said operation cavity is provided, at its inlet, with a spring- biased seal for airtightly receiving the vane. 3. A vane pump comprising: an operation cavity formed in a hollow cylindrical driven rotor rotatably received in a housing, said cavity having a flat bottom and a curved wall; and a vane received in said operation cavity and integrally extending from a drive rotor, said drive rotor being received in a cylindrical space of the driven rotor and rotatable about a drive shaft. 4. A vane pump comprising: a hollow cylindrical driven rotor rotatably received in a housing and provided, at its opposed portions, with a first operation cavity and a first vane; and a drive rotor eccentrically received in a cylindrical space of the driven rotor and rotatable about a drive shaft, said drive rotor being provided, at its opposed portions, with a second vane and a second operation cavity, said second vane and said second cavity engaging with the first cavity and the first vane respectively. 5. A vane pump comprising: a hollow cylindrical drive rotor received in a housing and provided, at its opposed portions, with a first operation cavity and a first vane and rotatable about a drive shaft; and a driven rotor eccentrically received in a cylindrical space of the drive rotor, said driven rotor being provided, at its opposed portions, with a second vane and a second operation cavity, said second vane and said second cavity engaging with the first cavity and the first vane respectively. 6. A vane pump comprising: a hollow cylindrical drive rotor received in a housing and rotatable about a drive shaft, said drive rotor having a vane integrally extending from an inner wall of the drive rotor; and a driven rotor rotatably eccentrically received in a cylindrical space of the drive rotor, said driven rotor having a cavity provided with an opening for receiving the vane of the drive rotor. 7. A vane pump comprising: a drive rotor rotatable about a drive shaft by outside rotational force and having a vane integrally extending from an inner wall of the drive rotor; a driven rotor eccentrically received in a cylindrical space of the drive rotor and rotatable about an eccentric shaft, said driven rotor having a cylindrical cavity for receiving a rotor body, said rotor body having a slit for receiving the vane of the drive rotor. •

Inventors: HWANG DONG IL, HWANG VIN, HWANG, DONG, IL, HWANG, VIN
Applicants: HWANG DONG IL, HWANG VIN, HWANG, DONG, IL, HWANG, VIN
Application year: 1995
Main classification: F04C2
IPC codes: F04C2