JP6570830B2 - Vacuum pump - Google Patents

Description

  The present invention relates to a vacuum pump that discharges air by rotation of a rotating body.

  A vacuum pump having a rotating body includes a pump unit that houses the rotating body, an inlet that takes air into the pump unit from the outside, and an outlet that discharges air to the outside. For example, the vacuum pump described in Patent Document 1 is a vane pump, and compresses the air sucked into the pump unit between adjacent vanes provided in a rotor that is a rotating body, and then out of the pump unit. Discharge.

Japanese Patent Laid-Open No. 2003-222090

  This type of vacuum pump has a problem that noise is generated when the air compressed by the pump unit is discharged from the outlet. For this reason, there has been a demand for a vacuum pump that can reduce noise accompanying air discharge. Such a problem is not limited to the vane pump but is generally common to vacuum pumps including a rotating body.

  This invention is made | formed in view of such a situation, The objective is to provide the vacuum pump which can reduce the noise accompanying exhaust_gas | exhaustion.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A vacuum pump that solves the above problems includes a pump unit that houses a rotating body, a pump chamber that houses the pump unit, a pump chamber inlet that takes air into the pump chamber, a pump chamber outlet that discharges air from the pump chamber, And a body having an exhaust groove into which air discharged from the pump chamber outlet flows, and a cover that is assembled to the body to cover the exhaust groove to form an exhaust passage, An annular passage provided on the outer periphery of the pump chamber, comprising an exhaust outlet communicating with the outlet of the body, wherein at least one of the cover and the body is provided with a partition wall defining the exhaust passage, The gist is to form a passage longer than the shortest length from the pump chamber outlet to the exhaust outlet along the exhaust passage by the partition wall.

  In the above configuration, by providing the partition wall in the annular exhaust passage, a passage longer than the shortest length along the exhaust passage from the pump chamber outlet to the exhaust outlet is formed, so compared to the shortest length route, The length of the exhaust passage can be increased. For this reason, since the effect which attenuates the vibration energy of the air in an exhaust passage can be heightened, reduction of the noise accompanying discharge | emission of air can be aimed at. In addition, by rectifying the air by passing it along the outer circumferential direction of the pump chamber, air pulsation generated when the air is discharged from the pump chamber outlet, or collision of air in the exhaust passage Etc., and the generation of noise can be suppressed.

In the vacuum pump, it is preferable that a partition wall lower than the height of the exhaust passage is provided in the exhaust groove.
In the above configuration, since the partition wall is lower than the height of the exhaust passage, the partition wall is provided in the middle of the exhaust passage, thereby reducing the flow path cross-sectional area in the exhaust passage. The partition wall functions as a throttle that generates a pressure difference between the upstream side and the downstream side in the exhaust passage. The air passing through the exhaust passage is expanded at a portion other than the partition wall and contracts when passing through the partition wall. As the air expands and contracts in the exhaust passage in this way, air pulsation generated when the air is discharged from the outlet of the pump chamber is attenuated, so that the noise reduction effect can be enhanced.

With respect to the vacuum pump, it is preferable that the cover includes a protrusion projecting into the exhaust passage on a surface that becomes the body side when assembled to the body.
In the above configuration, the protrusion functions as a throttle that generates a pressure difference between the upstream side and the downstream side in the exhaust passage. Therefore, the air passing through the exhaust passage is expanded at a portion other than the protrusion, and the protrusion is Shrink when passing. As the air expands and contracts in the exhaust passage in this way, air pulsation generated when the air is discharged from the outlet of the pump chamber is attenuated, so that the noise reduction effect can be enhanced.

In the vacuum pump, it is preferable that the cover includes a cylindrical portion and a ceiling portion that closes one opening of the cylindrical portion, and the ceiling portion and the pump portion are separated from each other.
In the above configuration, a space is provided between the ceiling portion of the cover and the pump portion by separating the ceiling portion of the cover and the pump portion. This space attenuates the vibration energy when the vibration of the pump part is transmitted to the ceiling part of the cover, so that the noise due to the vibration of the ceiling part can be reduced. Moreover, the space between the ceiling part of the cover and the pump part can increase the volume of the exhaust passage formed by covering the exhaust groove with the cover. For this reason, the expansion effect of air can be heightened.

About the said vacuum pump, it is preferable to provide a rib in the ceiling part of the said cover.
In the above configuration, the ribs are provided on the ceiling portion, whereby the strength of the ceiling portion itself can be increased, and as a result, noise due to vibration of the ceiling portion itself can be suppressed.

In the vacuum pump, the cover is preferably made of resin.
In the above configuration, the cover is formed of a resin having a sound absorbing effect as compared with a metal or the like, so that the noise reduction effect can be enhanced.

  According to the present invention, noise accompanying exhaust can be reduced.

The perspective view which shows the whole about one Embodiment of a vacuum pump. The perspective view of the state which removed the outer cover about the vacuum pump of the embodiment. The disassembled perspective view of components except an outer cover about the vacuum pump of the embodiment. The top view of the state which removed the outer cover about the vacuum pump of the embodiment. The perspective view which looked at the outer cover of the vacuum pump of the embodiment from the opening end side. The perspective view of the state which partially cut off the outer cover of the vacuum pump of the embodiment. Sectional drawing explaining the positional relationship of the outer cover and body of the vacuum pump of the embodiment. Sectional drawing explaining the flow of the air in the vacuum pump of the embodiment. 9-9 sectional drawing in FIG. 8 of the vacuum pump of the embodiment.

Hereinafter, an embodiment of the vacuum pump will be described with reference to FIGS.
First, the overall structure of the vacuum pump will be described in detail with reference to FIGS.
As shown in FIG. 1, the vacuum pump includes a motor 11, a body 12 that closes the opening of the motor 11, and an outer cover 13 that is assembled to the body 12. This vacuum pump is a dry pump in which the air taken in does not come into contact with the lubricating oil.

  The body 12 is a part formed from a metal such as aluminum, and is provided on the output shaft side of the motor 11. That is, the body 12 also functions as a lid that closes the case of the motor 11. The body 12 is provided with a body inlet 20 that takes air into the body 12 and a body outlet 21 that discharges air from the body 12. A connecting pipe 14 connected to a tank or the like to be decompressed is inserted into the body inlet 20.

  The outer cover 13 is made of resin and includes a cylindrical cylindrical portion 81 and a ceiling portion 80 that closes one end of the cylindrical portion 81. Bolt penetrating portions 50 for penetrating the bolts 16 a to 16 d are provided at four locations on the outer periphery of the cylindrical portion 81. The bolts 16a to 16d are hexagon socket head cap bolts, for example. The outer cover 13 is assembled to the body 12 with its open end in contact with the side surface 24 on the cover side, which is one surface of the body 12. The bolts 16 a to 16 d are passed through the bolt penetration part 50 and are screwed into screw holes 12 a to 12 d (see FIG. 2) formed in the body 12, so that the outer cover 13 is fixed to the body 12.

  As shown in FIG. 2, the body 12 includes a cylindrical outer wall portion 12f and a bottom portion 12e. The outer wall portion 12f is provided with an attachment portion 12g for attaching the vacuum pump to an external device or the like. A cylindrical housing wall 25 that houses a pump portion 60 that functions as a pump is provided further inside the outer wall portion 12 f of the body 12. The inside of the storage wall 25 corresponds to the pump chamber 27. The distal end surface of the housing wall 25 is formed on the same plane as the distal end surface of the side surface 24 on the cover side. The height of the pump unit 60 is higher than the height of the pump chamber 27. For this reason, a part of the pump unit 60 is accommodated in the pump chamber 27 so as to protrude from the tip of the accommodation wall 25.

  With reference to FIG. 3, each part which comprises a vacuum pump is explained in full detail. FIG. 3 shows a state in which components other than the outer cover 13 are arranged in the extending direction of the output shaft 15 of the motor 11.

  A through hole 28 through which the output shaft 15 of the motor 11 passes is formed in the center of the bottom 12 e of the body 12. The through hole 28 is formed at a position shifted from the center of the bottom portion 26 of the pump chamber 27.

  A pump chamber inlet 30 for taking air into the pump chamber 27 and a pump chamber outlet 31 for discharging air from the pump chamber 27 are formed through the housing wall 25. The pump chamber inlet 30 communicates with the body inlet 20.

  The pump chamber outlet 31 communicates with an exhaust groove 40 provided outside the accommodation wall 25. The exhaust groove 40 is formed in an annular shape along the outer peripheral surface of the housing wall 25. The exhaust groove 40 is provided with a first partition wall 41, a second partition wall 42, and a third partition wall 43 that partition the exhaust groove 40. The exhaust groove 40 is partitioned into a first exhaust groove 45, a second exhaust groove 46, and a third exhaust groove 47 in order from the pump chamber inlet 30 side by the first partition wall 41 to the third partition wall 43. The height of the first partition wall 41 to the third partition wall 43 is lower than the height of the accommodation wall 25.

  Three bolt mounting portions 33 for mounting the bolts 34a, 34b, 34c are formed on the opening end side of the housing wall 25. The bolt mounting portion 33 is formed at the same position as the first partition wall 41 to the third partition wall 43 in the circumferential direction of the housing wall 25. A stepped portion 48 is provided on the outer peripheral surface of the housing wall 25. The bolt mounting portion 33 is provided in a state continuous with the stepped portion 48.

In the body 12, an exhaust outlet 49 (see FIG. 2) communicating with the body outlet 21 is provided in the third exhaust groove 47 and in the vicinity of the first partition wall 41.
The pump unit 60 accommodated in the pump chamber 27 includes a cylinder 61 and a rotor 72 that is a rotating body. The cylinder 61 is made of metal such as iron and is formed in a cylindrical shape. The cylinder 61 is formed with an inlet side communication hole 62 formed at a position corresponding to the pump chamber inlet 30 of the pump chamber 27 and an outlet side communication hole 64 formed at a position corresponding to the pump chamber outlet 31. ing.

  Inside the cylinder 61, a rotor 72 in which a vane 73 is movably accommodated is accommodated rotatably. The rotor 72 is made of metal such as iron, and has a shaft hole 74 and five vane receiving grooves 75 formed therein. A press-fit pin 76 that is press-fitted into the tip of the output shaft 15 of the motor 11 and presses the tip of the output shaft 15 against the inner peripheral surface of the shaft hole 74 is inserted into the shaft hole 74. The press-fit pin 76 is press-fitted into the distal end of the output shaft 15 in a state where the output shaft 15 is inserted into the shaft hole 74 of the rotor 72. Carbon vanes 73 are accommodated in the vane accommodating grooves 75, respectively.

  Of the pair of openings of the cylinder 61, the opening on the body 12 side is closed by the body side plate 70. The other opening of the cylinder 61 is closed by the cover side plate 71. The body side plate 70 and the cover side plate 71 are made of a material such as carbon having a small friction coefficient with respect to the vane 73, and are formed in a disk shape. The body side plate 70 includes a hole 70 a through which the output shaft 15 of the motor 11 is inserted.

  The pump unit 60 includes a pump cover 77 formed in a disc shape. The pump cover 77 is made of metal, and is formed with bolt insertion holes 77a for inserting the bolts 34a to 34c. A cylinder 61 is press-fitted into the body 12, and a body-side plate 70, a rotor 72, a cover-side plate 71, and a pump cover 77 are combined with the press-fitted cylinder 61. In this state, the bolts 34 a to 34 c are inserted into the bolt insertion holes 77 a of the pump cover 77, and these members are assembled to the body 12 by being screwed to the bolt mounting portion 33 on the body 12 side.

  Next, the operation of the pump unit 60 will be described with reference to FIG. In the pump chamber 27, a substantially crescent-shaped space 78 is formed by a rotor 72 attached eccentrically in the pump chamber 27.

  When the rotor 72 is rotated by driving the motor 11, the vane 73 projects outward in the radial direction of the rotor 72 along the vane receiving groove 75 due to centrifugal force, and the tip thereof is brought into contact with the inner peripheral surface 61 a of the cylinder 61. Thus, a substantially crescent-shaped space 78 in the pump chamber 27 is partitioned into five compression chambers surrounded by the five vanes 73, the outer peripheral surface of the rotor 72, and the inner peripheral surface 61 a of the cylinder 61.

  These compression chambers move in the same direction as the rotor 72 rotates. When the compression chamber moves, the volume of the compression chamber increases near the pump chamber inlet 30 and decreases at the pump chamber outlet 31. That is, the air sucked into one compression chamber from the pump chamber inlet 30 is compressed as the rotor 72 rotates, and is discharged from the pump chamber outlet 31. In the pump unit 60, the rotor 72 and the vane 73 rotate in the cylinder 61 to compress the air, so that the compressed air is intermittently discharged from the pump chamber outlet 31.

Next, the outer cover 13 will be described with reference to FIGS. 5 and 6.
As shown in FIG. 5, the outer cover 13 includes a ceiling portion 80 that forms the bottom of the outer cover 13, and a cylindrical cylindrical portion 81 that is provided along the edge of the ceiling portion 80.

  Radial ribs 88 are formed on the surface of the ceiling portion 80 of the outer cover 13 that is disposed on the body 12 side when assembled to the body 12. The radial rib 88 includes an annular rib 89 provided at the center of the ceiling portion 80 and six linear ribs 92 extending linearly from the annular rib 89 toward the cylindrical portion 81. The radial ribs 88 suppress the vibration of the ceiling portion 80 by reinforcing the ceiling portion 80. Thereby, the noise accompanying the vibration of the ceiling part 80 is suppressed.

  A first protrusion 86 and a second protrusion 87 are formed on the cylindrical portion 81 of the outer cover 13. The first protrusion 86 and the second protrusion 87 protrude from the cylindrical portion 81 toward the radially inner side of the outer cover 13, and are continuous with the ceiling portion 80.

  A curved wall portion 83 that defines an arc-shaped space 82 that is an arc-shaped space is formed inside the outer cover 13. The curved wall portion 83 protrudes from the ceiling portion 80 and is formed in a state where both ends thereof are connected to the cylindrical portion 81. The curved wall 83 is formed such that the width W in the short direction of the arcuate space 82 on the inner side increases from one end 85 to the other end 84 in the longitudinal direction of the arcuate space 82.

  The arcuate space 82 defined by the curved wall portion 83 faces the first exhaust groove 45 when the outer cover 13 is assembled to the body 12. The arc-shaped space 82 and the first exhaust groove 45 constitute a small expansion chamber 91 that expands the air discharged from the pump chamber 27.

  As shown in FIG. 6, of both ends 84 and 85 of the curved wall 83, the end 84 having a relatively large width W of the arc space 82 is when the outer cover 13 is assembled to the body 12. , Abuts on the first partition wall 41. A partition wall 90 that separates the pump chamber outlet 31 and the exhaust outlet 49 is formed by the end portion 84 and the first partition wall 41.

  Next, referring to FIG. 7, the curved wall 83, the first protrusion 86 and the second protrusion 87 of the outer cover 13, and the first exhaust groove 45 to the third exhaust groove 47 of the body 12 are relative to each other in the circumferential direction. Explain the position.

  The output shaft 15 of the motor 11 is eccentric with respect to the center of the pump chamber 27, but coincides with the radial center of the outer cover 13. The exhaust outlet 49 formed at the end of the third exhaust groove 47 and the pump chamber outlet 31 formed at the start of the first exhaust groove 45 are the first partition wall 41 of the body 12 and the curved wall portion 83 of the outer cover 13. Are separated by a partition wall 90 constituted by the end portions 84 of each other.

  When the angle at which the surface of the partition wall 90 on the side of the first exhaust groove 45 is centered on the output shaft 15 is “0 °”, the pump chamber outlet 31 is angled θ1 clockwise (direction) from the position of the partition wall 90. It is provided in the position. The starting end of the first exhaust groove 45 is located at an angle “0 °”, and the end of the first exhaust groove 45 is located at an angle θ2. The second exhaust groove 46 is provided from the angle θ3 to the angle θ4. The third exhaust groove 47 is provided from the angle θ5 to the angle θ6. The exhaust outlet 49 is provided at an angle θ7 smaller than the angle θ6. The first exhaust groove 45 to the third exhaust groove 47 become the first expansion chamber 96 to the third expansion chamber 98 by being covered with the outer cover 13. The first expansion chamber 96 to the third expansion chamber 98 constitute an exhaust passage 110.

  That is, the exhaust passage 110 including the first expansion chamber 96 to the third expansion chamber 98 is provided over 360 ° when the thickness of the first partition wall 41 to the third partition wall 43 is included. The angle from the angle θ1 that is the position of the pump chamber outlet 31 to the angle θ7 that is the position of the exhaust outlet 49 is an angle “θ7−θ1”. The angle “θ7−θ1” is preferably larger than 180 °. In order to lengthen the exhaust passage 110, the angle “θ7−θ1” is desirably as large as possible, and is preferably 270 ° or more.

  The curved wall portion 83 is in contact with the body 12 side at a portion including the one end portion 84 thereof. Of the curved wall portion 83, the wall portion on the housing wall 25 side is provided on the radially outer side of the housing wall 25 and does not contact the housing wall 25. In this way, by minimizing the portion of the curved wall 83 that contacts the body 12 side, vibration due to contact between the body 12 and the outer cover 13 can be suppressed.

  The curved wall portion 83 extends from the angle “0 °” to the angle θ10 along the first exhaust groove 45. A small expansion chamber 91 is defined by the curved wall portion 83 and the first exhaust groove 45. Further, the angle θ10 that is the terminal position of the curved wall portion 83 is smaller than the angle θ2 that is the terminal position of the first exhaust groove 45. As a result, the first exhaust groove 45 is provided with an opening 95 that is not covered by the curved wall 83.

  A first expansion chamber 96 is defined by the first exhaust groove 45, the outer cover 13, and the pump unit 60. The first expansion chamber 96 includes a small expansion chamber 91 formed by the arcuate space 82 and the first exhaust groove 45. Further, the second expansion chamber 97 is defined by the second exhaust groove 46, the outer cover 13, and the pump unit 60. The first protrusion 86 is provided between the first expansion chamber 96 and the second expansion chamber 97.

  A gap is provided between the radial tip of the first protrusion 86 and the pump unit 60. The angle θ11 that is the position of the first protrusion 86 is larger than the angle θ3 that is the position of the start end of the second exhaust groove 46. That is, the first protrusion 86 is provided at a position shifted from the starting end of the second exhaust groove 46, and a first inflow port 99 is formed between them.

  A third expansion chamber 98 is defined by the third exhaust groove 47, the outer cover 13, and the pump unit 60. The second protrusion 87 is provided between the second expansion chamber 97 and the third expansion chamber 98. A gap is provided between the distal end of the second protrusion 87 in the radial direction and the pump unit 60. The angle θ12, which is the position where the second protrusion 87 is provided, is larger than the angle θ4, which is the end of the second exhaust groove 46, and smaller than the angle θ5, which is the start end of the third exhaust groove 47. Accordingly, the second inflow port 100 is formed between the second protrusion 87, the body 12, and the pump unit 60.

Next, the operation of the vacuum pump will be described with reference to FIGS.
As shown in FIG. 8, when the rotor 72 is rotated by driving the motor 11, air is taken into the pump chamber 27 from the pump chamber inlet 30 through the connection pipe 14. The air sucked into the compression chamber partitioned by the vane 73 or the like is compressed and discharged from the pump chamber outlet 31 to the small expansion chamber 91 as indicated by an arrow D1.

  The air discharged into the small expansion chamber 91 is directly connected to the body outlet 21 by the partition wall 90 constituted by the first partition wall 41 of the body 12 and the curved wall portion 83 of the outer cover 13. Flow is hindered. In other words, the first expansion chamber 96 and the third expansion chamber 98 are not in direct communication with each other by the partition wall 90. For this reason, after the air discharged into the small expansion chamber 91 is expanded in the small expansion chamber 91, it passes between the opening 95, the outer cover 13, and the pump unit 60 as indicated by an arrow D <b> 2. Then, it flows into the second expansion chamber 97 from the first inflow port 99. At this time, since the height of the second partition wall 42 is lower than the height H of the exhaust passage 110 (see FIG. 9), the second partition wall 42 serves as a throttle that allows air to pass while generating a pressure difference between the upstream side and the downstream side. Functions and contracts air flow. Further, the first inlet 99 provided between the first expansion chamber 96 and the second expansion chamber 97 also functions as a throttle, and contracts the air flow.

  The air that has flowed into the second expansion chamber 97 expands again and then passes through the second inlet 100 and flows into the third expansion chamber 98 as indicated by an arrow D3. Since the height of the third partition wall 43 is lower than the height H of the exhaust passage 110 (see FIG. 9), the third partition wall 43 functions as a throttle for reducing the cross-sectional area of the flow path while allowing air to pass therethrough. Shrink. The second inlet 100 also functions as a throttle that reduces the cross-sectional area of the flow path, and contracts the air flow. The air flowing into the third expansion chamber 98 expands again and then flows into the communication passage 17 from the exhaust outlet 49 as indicated by an arrow D4. Since the communication passage 17 has a smaller flow path cross-sectional area than the third expansion chamber 98, the flow of air flowing into the communication passage 17 is contracted and discharged from the body outlet 21 as indicated by an arrow D5.

  As shown in FIG. 9, an urging unit 102 such as a wave washer is provided between the pump unit 60 and the outer cover 13 to press the pump unit 60 against the body 12 side. Further, since the ceiling portion 80 of the outer cover 13 and the pump portion 60 are separated from each other, a gap 101 is provided between the ceiling portion 80 of the outer cover 13 and the pump portion 60. For this reason, since the vibration of the rotor 72 is transmitted to the outer cover 13 side through the gap 101, the vibration energy of air is attenuated and the vibration of the outer cover 13 is suppressed. A part of the air discharged from the small expansion chamber 91 passes through the gap 101, crosses the pump unit 60, and goes to the exhaust outlet 49 side. However, since the height of the gap 101 is smaller than the volume of the first expansion chamber 96 to the third expansion chamber 98, most of the air discharged from the small expansion chamber 91 is directed to the second expansion chamber 97 side.

  In this type of vacuum pump, since the rotor 72 provided with the vane 73 rotates, compressed air is intermittently discharged from the pump chamber outlet 31, so the distance from the pump chamber outlet 31 to the body outlet 21 is short. Then, noise may be generated at the body outlet 21 due to pressure pulsation occurring at a certain basic frequency.

  In the vacuum pump provided with the exhaust passage 110, most of the air discharged from the pump chamber outlet 31 is discharged from the body outlet 21 after passing through the annular exhaust passage 110 outside the pump chamber 27. Compared to the shortest path from the pump chamber outlet 31 to the exhaust outlet 49, the path length from the pump chamber outlet 31 to the body outlet 21 becomes longer. Since the vibration energy of air is attenuated as the distance that the air flows becomes longer, the noise can be reduced by increasing the flow path length from the pump chamber outlet 31 to the body outlet 21.

  Further, the air repeats expansion and contraction a plurality of times between the pump chamber outlet 31 and the body outlet 21. As a result, air pulsation is attenuated, and noise caused by vibration is suppressed. Further, when the air passes through the exhaust passage 110, the air swirls around the outer periphery of the pump unit 60, so that the air can be rectified. For this reason, the pulsation of the air generated when air is discharged from the pump chamber outlet 31, the collision of the air in the exhaust passage 110, and the like can be suppressed, and the generation of noise can be suppressed. Further, since the outer cover 13 is made of a resin having a sound absorbing property compared to metal or the like, vibration of the air discharged from the exhaust outlet 49 can be suppressed.

As described above, according to the vacuum pump of the present embodiment, the following effects can be obtained.
(1) Since the partition wall 90 is provided in the annular exhaust passage 110, a passage longer than the shortest length along the exhaust passage 110 from the pump chamber outlet 31 to the exhaust outlet 49 is formed. Compared to the route, the route length of the exhaust passage 110 can be increased. For this reason, since the effect of attenuating the vibration energy of air in the exhaust passage 110 can be enhanced, noise associated with exhaust from the body outlet 21 can be reduced. Further, the air is rectified by passing along the outer peripheral direction of the pump chamber 27, thereby pulsating air generated when the air is discharged from the pump chamber outlet 31, and air in the exhaust passage 110. The collision between each other can be suppressed, and the generation of noise can be suppressed.

(2) Since the second partition wall 42 and the third partition wall 43 are lower than the height H of the exhaust passage 110, the air passage is reduced while the cross-sectional area in the exhaust passage is reduced, and the exhaust passage 110. It functions as a throttle that generates a pressure difference between the upstream side and the downstream side. Air passing through the exhaust passage 110 is expanded by the second partition wall 4 2 and a portion other than the third partition wall 43, it shrinks as it passes through the second partition wall 4, second and third partition wall 43. As described above, the air expands and contracts in the exhaust passage 110, whereby the air pulsation generated when the air is discharged from the pump chamber outlet 31 is attenuated, so that the noise reduction effect can be enhanced.

  (3) Since the first protrusion 86 and the second protrusion 87 function as a throttle that generates a pressure difference between the upstream side and the downstream side in the exhaust passage 110, the air passing through the exhaust passage 110 is It is expanded at a portion other than the protrusion 86 and the second protrusion 87 and contracts when passing through the first protrusion 86 and the second protrusion 87. As the air expands and contracts in the exhaust passage in this way, air pulsation generated when the air is discharged from the pump chamber outlet 31 is attenuated, so that the noise reduction effect can be enhanced.

  (4) The gap 101 is provided between the ceiling portion 80 and the pump portion 60 by separating the ceiling portion 80 of the outer cover 13 from the pump portion 60. When the vibration of the pump unit 60 is transmitted to the ceiling 80 of the outer cover 13 due to the gap 101, the vibration energy is attenuated, so that noise due to the vibration of the ceiling 80 can be reduced. The volume of the exhaust passage 110 formed by the outer cover 13 covering the first exhaust groove 45 to the third exhaust groove 47 is increased by the gap 101 between the ceiling part 80 of the outer cover 13 and the pump part 60. can do. For this reason, the expansion effect of air can be heightened.

  (5) By providing the radial ribs 88 on the ceiling portion 80 of the outer cover 13, the strength of the ceiling portion 80 itself can be increased, and thus noise due to vibration of the ceiling portion 80 itself can be suppressed.

(6) Since the outer cover 13 is formed of a resin having a sound absorbing effect compared to metal or the like, the noise reduction effect can be enhanced.
In addition, the said embodiment can also be implemented with the following forms.

  In the above embodiment, the first partition wall 41 formed on the body 12 and the end 84 of the curved wall portion 83 formed on the outer cover 13 have the shortest length from the pump chamber outlet 31 to the exhaust outlet 49. A partition wall 90 that suppresses the flow of air through the path was formed. In addition to this aspect, the partition may be formed only by the first partition wall 41 formed in the body 12. In this case, the first partition wall 41 is formed higher than the height of the first exhaust groove 45 and protrudes toward the outer cover 13. When the outer cover 13 is assembled with the body 12, the first partition wall 41 is inserted into the ceiling portion 80 side of the outer cover 13. Further, the partition wall may be formed by the end portion 84 of the curved wall portion 83 formed in the outer cover 13. In this case, at least the end portion 84 of the curved wall portion 83 protrudes from the opening end of the outer cover 13, and when the outer cover 13 is assembled to the body 12, the end portion 84 is inserted into the exhaust groove 40 side. .

In the above embodiment, the exhaust groove 40 is divided into three by the first partition wall 41 to the third partition wall 43. However, the exhaust groove 40 may be divided into two or may be divided into four or more. Good.
The number of protrusions of the outer cover 13 that functions as a throttle for reducing the cross-sectional area of the flow path may be one, or may be three or more. Moreover, the height and the length along the radial direction of the outer cover 13 can be changed. For example, the protrusion may have a height that is inserted into the body 12 side.

  The number of partition walls of the body 12 that functions as a throttle for reducing the flow path cross-sectional area may be one, or a plurality of three or more. Moreover, the height and the length along the radial direction of the body 12 can be changed. For example, the partition wall may have a height inserted into the outer cover 13 side.

  -The ceiling part 80 of the outer cover 13 and the pump part 60 may contact. In this case, it is preferable that an absorbing material or the like that absorbs vibration is provided between the ceiling portion 80 of the outer cover 13 and the pump portion 60.

  -Although the radial rib 88 was formed in the ceiling part 80 of the outer cover 13, you may form a rib of shapes other than this. For example, a plurality of protrusions that intersect at the radial center may be formed. A plurality of protrusions extending in parallel may be formed.

  In the above-described embodiment, the resin outer cover 13 is employed. However, for example, a metal outer cover 13 other than resin may be employed. In the case of the metal outer cover 13, it is preferable that an absorbing material or the like that absorbs vibration is provided between the ceiling portion 80 of the outer cover 13 and the pump portion 60.

  In the above embodiment, the vacuum pump is provided with the motor 11 as a drive source. However, the vacuum pump is not necessarily provided with a drive source, and may be connected to an external drive source. For example, a rotating shaft inserted through the rotor 72 may be connected to the crankshaft side of the engine. Moreover, you may connect with the rotating shaft of another drive device.

  In the above embodiment, the pump unit 60 is accommodated in the pump chamber 27 in a state in which a part thereof protrudes from the pump chamber 27. However, the pump unit 60 has a height equal to or lower than the height of the pump 27 chamber. May be accommodated without protruding from the pump chamber 27.

  In the above embodiment, the cylinder 61 and the body 12 are separated from each other, and the pump 61 including the cylinder 61 is fixed to the body 12 by press-fitting the cylinder 61 and screwing the bolts 34a to 34c. 61 may be cast in the body 12. Further, the cylinder 61 and the body 12 may be the same member, and the cylinder 61 may be omitted.

  -In above-mentioned embodiment, although the vacuum pump was actualized to the vane pump, types of pumps other than a vane pump may be sufficient. For example, a gear pump including a pair of gears that mesh with each other as a rotating body may be used.

  -Since the vacuum pump of the said embodiment is a dry pump and noise is reduced, it can be used as a vacuum source of a versatile apparatus. For example, it can also be used for a vacuum source used for a booster of a vehicle brake system, a vacuum source for a packaging machine, a printing machine, a bookbinding machine, a labeling vacuum source, a robot vacuum source, or the like.

  DESCRIPTION OF SYMBOLS 11 ... Motor, 12 ... Body, 12a-12d ... Screw hole, 12e ... Bottom part, 12f ... Outer wall part, 13 ... Outer cover, 14 ... Connection pipe, 15 ... Output shaft, 16a-16d ... Bolt, 17 ... Communication path, DESCRIPTION OF SYMBOLS 20 ... Body inlet, 21 ... Body outlet, 24 ... Side surface, 25 ... Housing wall, 26 ... Bottom part, 27 ... Pump chamber, 28 ... Insertion hole, 30 ... Pump chamber inlet, 31 ... Pump chamber outlet, 33 ... Bolt attachment 34a to 34c ... bolt, 40 ... exhaust groove, 41-43 ... first partition wall to third partition wall, 45-47 ... first exhaust groove to third exhaust groove, 48 ... step portion, 49 ... exhaust outlet 50 ... Bolt penetration part, 60 ... Pump part, 61 ... Cylinder, 62 ... Inlet side communication hole, 63 ... Outlet side communication hole, 70 ... Body side plate, 70a ... Hole, 71 ... Cover side plate, 73 ... Vane, 74 ... shaft hole, 75 ... vane receiving groove, 6 ... Press-fit pin, 72 ... Rotor, 77 ... Pump cover, 80 ... Ceiling part, 81 ... Cylindrical part, 82 ... Arc space, 83 ... Curved wall part, 84, 85 ... End part, 86 ... First projection part, 87 2nd protrusion, 88 ... radial rib, 89 ... annular rib, 90 ... partition wall, 91 ... small expansion chamber, 92 ... linear rib, 95 ... opening, 96-98 ... 1st expansion chamber-3rd expansion chamber, 99 ... first inlet, 100 ... second inlet, 101 ... gap.

Claims (5)

A pump unit containing a rotating body;
A body including a pump chamber that houses the pump section, a pump chamber inlet that takes air into the pump chamber, a pump chamber outlet that discharges air from the pump chamber, and an exhaust groove into which air discharged from the pump chamber outlet flows When,
A cover that covers the exhaust groove to form an exhaust passage by being assembled to the body,
The exhaust passage is an annular passage provided on the outer periphery of the pump chamber, and includes an exhaust outlet communicating with the outlet of the body.
The cover defines an expansion chamber for expanding the air discharged from the exhaust outlet, and includes a curved wall portion that curves along the shape of the exhaust passage ,
The body includes a plurality of partition walls that partition the exhaust passage, the partition wall being lower than a height of the exhaust passage, and one partition wall is formed by a partition wall constituted by the partition wall and the curved wall portion. Forming a passage that is longer than the shortest length from the pump chamber outlet to the exhaust outlet along the exhaust passage, and the other partition wall does not contact the cover and reduces the flow passage cross-sectional area of the exhaust passage. A featured vacuum pump. The vacuum pump according to claim 1 , wherein
The said cover is provided with the protrusion part which protrudes in the said exhaust passage in the surface used as the said body side when assembled | attached to the said body. The vacuum pump characterized by the above-mentioned. The vacuum pump according to claim 1 or 2 ,
The said cover is provided with the cylindrical part and the ceiling part which obstruct | occludes one opening of the said cylindrical part, The said ceiling part and the said pump part are spaced apart. The vacuum pump characterized by the above-mentioned. In the vacuum pump of any one of Claims 1-3 ,
A vacuum pump comprising a rib on the ceiling of the cover. Vacuum pump according to any one of claims 1-4 wherein the cover made of a resin.