JP2014055580A - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage vacuum pump that can prevent a cylinder from corroding and can cool the inside of the multistage vacuum pump without complicating the structure of the cylinder.SOLUTION: Partition walls 14 and 15 of a cylinder 1 are formed on the inside of a cylinder body 11 and define a first pump chamber 31, a second pump chamber 32, and a third pump chamber 33. A through-hole 11a is formed in the cylinder body 11, and a cooling pipe 51 is provided so as to be inserted into the through-hole 11a. The cooling pipe 51 is led from the outside of the cylinder 1 into the cylinder 1 along the through-hole 11a, passed through the partition wall 14, and led to the outside of the cylinder 1. The partition wall 14 inside the cylinder 1 can be cooled by passing a cooling medium through the cooling pipe 51. Because a passage through which the cooling medium is passed is formed in the cooling pipe 51, which is a member different from the cylinder 1, the cylinder 1 can be prevented from corroding, and the cylinder 1 can be easily produced without complicating the structure of the cylinder 1.

Description

  The present invention relates to a positive displacement vacuum pump, and more particularly to a multistage vacuum pump having a plurality of pump chambers.

  The volume transfer type vacuum pump is used, for example, in the manufacturing field of semiconductor devices, FPDs (Flat Panel Displays), and the like when performing vacuum evacuation. In general, in a multistage vacuum pump having a plurality of pump chambers, it is possible to exhaust gas to a low ultimate pressure by compressing the gas stepwise from the pump chamber on the intake side to the pump chamber on the exhaust side.

  In the rotary multistage vacuum pump described in Patent Document 1, an outer peripheral gas flow path that connects between one pump section and the next pump section is provided on the outer periphery of a housing having a plurality of pump sections each having a rotor. I have. The outer wall of the outer peripheral gas channel is formed by a cooler having a channel for flowing cooling water. Thereby, the gas discharged from one pump division can be cooled in the outer periphery gas flow path until it flows into the next pump division (for example, refer to paragraph [0006] in the specification of Patent Document 1).

  In the vacuum pump described in Patent Document 2, the refrigerant flow path is formed in the rear housing that forms the wall surface of the final-stage pump chamber. The refrigerant is circulated through the refrigerant flow path, and the vicinity of the bearing and the seal member provided in the rear housing is cooled, thereby extending the life of the bearing and the seal member (for example, the description in the specification of Patent Document 2). [0026]).

  However, in the vacuum pumps of Patent Documents 1 and 2, the cooling water flow path is disposed on the outer peripheral side of the housing or is disposed in the vicinity of the bearing structure of the rear housing. When it is provided, the efficiency of heat removal is poor, and it is difficult to cool the inside of the pump.

  In the claw-type vacuum pump described in Patent Document 3, a plurality of stages of pump chambers having a pair of rotors and a suction port or an outlet are provided, and a cooler and a cooling unit disposed downstream of the outlet of the pump chamber Gas is removed by the passage (see, for example, page 9 of the specification of Patent Document 3 and FIG. 1). In this vacuum pump, since the cooling passage is formed in the member that partitions the pump chamber, the member that partitions the pump chamber can be cooled by flowing the coolant through the passage. Thereby, the inside of a pump can be cooled.

Japanese Patent Laid-Open No. 2001-020884 Japanese Patent Laid-Open No. 2004-300964 Japanese National Patent Publication No. 9-502001

  However, in the claw-type vacuum pump described in Patent Document 3, since the cooling passage is directly formed in the casing, the use of the casing cannot be continued when corrosion such as rust occurs in the flow path. . Moreover, with such a flow path configuration, the structure of the casing becomes complicated and its manufacture becomes difficult.

  In view of the circumstances as described above, an object of the present invention is to provide a vacuum pump that can prevent the corrosion of the cylinder and can cool the inside of the multistage pump without complicating the structure of the cylinder. is there.

In order to achieve the above object, a vacuum pump according to an embodiment of the present invention includes a rotating shaft, a plurality of rotors, a cylinder, and a cooling pipe.
The plurality of rotors are arranged along the rotation axis and attached to the rotation axis.
The cylinder includes an outer wall, a plurality of pump chambers that respectively accommodate the plurality of rotors, and partition walls that partition the plurality of pump chambers, and rotatably support the rotation shaft.
The cooling pipe is introduced into the cylinder from the outside of the cylinder through the first region of the outer wall, passes through at least the partition wall, and passes through the second region of the outer wall on the opposite side of the first region. To the outside.

FIG. 1 is a schematic cross-sectional view showing a vacuum pump according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a vacuum pump according to the first embodiment of the present invention. FIG. 3 is a diagram showing the range of the partition walls. FIG. 4 is a schematic cross-sectional view showing a vacuum pump according to the second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a vacuum pump according to the second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing a vacuum pump according to the third embodiment of the present invention.

The vacuum pump which concerns on one form comprises a rotating shaft, a some rotor, a cylinder, and a cooling pipe.
The plurality of rotors are arranged along the rotation axis and attached to the rotation axis.
The cylinder includes an outer wall, a plurality of pump chambers that respectively accommodate the plurality of rotors, and partition walls that partition the plurality of pump chambers, and rotatably support the rotation shaft.
The cooling pipe is introduced into the cylinder from the outside of the cylinder through the first region of the outer wall, passes through at least the partition wall, and passes through the second region of the outer wall on the opposite side of the first region. To the outside.

  A multi-stage pump cylinder having a partition inside is provided with a cooling pipe so as to be introduced from one region of the outer wall into the cylinder and led out of the cylinder in the opposite region and at least through the partition wall. Therefore, the partition wall inside the pump can be cooled. Further, in this embodiment, the flow path for flowing the refrigerant to the cylinder is not directly formed, but cooling is performed by a cooling pipe formed as a separate member from the cylinder, so that corrosion of the cylinder itself can be prevented, In addition, the structure of the cylinder is not complicated, and the cylinder can be easily manufactured.

  The cooling pipe may be formed linearly. Thereby, manufacture of a cooling pipe becomes easy. Further, introduction and derivation when the cooling pipe is provided in the cylinder are facilitated.

  The cylinder may have a through hole formed in the first region, the partition wall, and the second region through which the cooling pipe passes.

  The vacuum pump may further include a sealing member provided between an outer surface of the cooling pipe and an inner surface of the through hole.

The cylinder may have a communication path that communicates from the outside to the through hole. For example, a thermally conductive filler can be introduced into the through hole through the communication path. Thereby, when letting a cooling pipe pass through the through-hole formed in the cylinder, heat conduction can be promoted without creating a gap between the cylinder and the cooling pipe. Therefore, even if a cooling pipe, which is a separate member from the cylinder, is used for cooling the inside of the cylinder, it is possible to obtain a good heat removal effect while suppressing a decrease in the efficiency of heat conduction.
For example, the communication path may communicate with the through-hole via a third region of the outer wall that is different from the first and second regions.

  The cylinder may have a plurality of communication paths. In this case, for example, when the thermally conductive filler is introduced into the through-hole through one of the plurality of communication passages, air is vented through another communication passage. It is possible to reliably fill the gap.

  The cooling pipe may be provided so as to pass through an internal space including the plurality of pump chambers of the cylinder. In this case, in addition to cooling the inside of the pump via the partition wall, the gas passing through the internal space of the cylinder can be directly cooled inside the pump.

  The cooling pipe may be formed of a metal material having antiseptic properties. Thereby, since rust and corrosion of the cooling pipe can be prevented, for example, water may be used as a coolant flowing through the cooling pipe. By passing such a cooling pipe through the cylinder, cooling can be performed by a simple method while reliably preventing corrosion by the refrigerant.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
FIG. 1 is a schematic cross-sectional view showing a vacuum pump according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG.
The vacuum pump 100 is a multi-stage Roots pump, and is used, for example, for evacuating a load lock chamber in a vacuum process in the field of manufacturing semiconductor devices and FPDs (Flat Panel Displays).

  As shown in FIG. 1, the vacuum pump 100 includes a cylinder 1 and a multistage rotor 2. The cylinder 1 has an outer wall 10, a plurality of pump chambers 31, 32, 33, and partition walls 14, 15 (see FIG. 3). The vacuum pump 100 is a three-stage vacuum pump having a first pump chamber 31, a second pump chamber 32, and a third pump chamber 33 as a plurality of pump chambers.

  The outer wall 10 of the cylinder 1 includes an outer peripheral wall 111 of a cylindrical cylinder body 11, a first cover 12 and a second cover that are airtightly attached to both ends (both ends in the X-axis direction in FIG. 1) of the cylinder body 11. And a cover 13. The outer wall 10 defines an internal space 30 including a plurality of pump chambers 31, 32, 33 of the cylinder 1. The internal space 30 communicates with a region outside the cylinder 1 through an intake port 301 and an exhaust port 302 provided in the cylinder 1. The intake port 301 is connected to the first pump chamber 31 on the low pressure side among the plurality of pump chambers, and the exhaust port 302 is connected to the third pump chamber 33 which is the final stage on the high pressure side. The high pressure side is the atmospheric pressure side.

  Of the outer wall 10 of the cylinder 1, the first cover 12 is provided on the low pressure side, and the second cover 13 is provided on the atmospheric pressure side. On the second cover 13 side (atmospheric pressure side) outside the cylinder 1, a driving source 40 that applies driving force to the vacuum pump 100 is disposed.

  The partition walls 14 and 15 of the cylinder 1 are formed integrally with the outer peripheral wall 111 inside the cylinder body 11, and sequentially from the first cover 12 side, the first pump chamber 31, the second pump chamber 32, and the third pump. The chamber 33 is partitioned. The first pump chamber 31 communicates with the second pump chamber 32 through a connection path 34 formed in the partition wall 14. The second pump chamber 32 communicates with the third pump chamber 33 through a connection path 35 formed in the partition wall 15. In addition, the connection paths 34 and 35 are included in the internal space 30 of the cylinder 1 like the plurality of pump chambers 31, 32, and 33.

  The vacuum pump 100 is provided with a pair of multistage rotors 2 (see FIG. 2). Since each multi-stage rotor 2 has substantially the same structure, one multi-stage rotor 2 will be described unless it is necessary to distinguish between the two multi-stage rotors 2. As shown in FIG. 1, the multistage rotor 2 includes a rotating shaft 20 and a plurality of rotors 21, 22, and 23. The plurality of rotors 21, 22, and 23 are aligned along the axial direction of the rotating shaft 20 and are attached to the rotating shaft 20.

  Rotors 21, 22, and 23 are accommodated in the pump chambers 31, 32, and 33 of the cylinder 1, respectively. Each rotor 21 is a trilobal roots-type rotor, and each of the pump chambers 31, 32, 33 is arranged so that the rotors 21, the rotors 22, and the rotors 23 of the two multistage rotors 2 mesh with each other. Has been placed. A minute gap is maintained between the rotors 21 and 21. In addition, a minute gap is also maintained between the rotors 21 and 21 and the cylinder 1. The same applies to the rotors 22 and 22 and the rotors 23 and 23.

  As shown in FIG. 1, the first cover 12 and the second cover 13 of the cylinder 1 have a function of rotatably supporting the two rotary shafts 20 and 20, respectively. Bearings 42, 42 and 43, 43 are attached to the first cover 12 and the second cover 13. One end of the rotary shaft 20 is supported by a bearing 42 and extends through the first cover 12 and into a gear housing 41 provided between the first cover 12 and the drive source 40. . The other end of the rotating shaft 20 extends to the second cover 13 and is supported by the bearing 43.

  Of the two rotary shafts 20, 20, one rotary shaft 20 is connected to the drive source 40. In addition, timing gears 24 are attached to the ends of the rotary shaft 20 inside the gear housing 41. The two timing gears 24, 24 have the same number of teeth and are provided so as to mesh with each other and rotate in opposite directions.

  As shown in FIG. 2, a through hole 11 a is formed in the cylinder body 11, and a cooling pipe 51 through which a coolant passes is provided in the through hole 11 a. For example, the through hole 11a is formed in a straight line through the partition wall 14 of the cylinder body 11 and the outer wall 10 formed continuously with the partition wall 14, and is perpendicular to the axial direction of the rotary shaft 20 (Y in FIG. 2). (Axial direction).

  The cooling pipe 51 is introduced from the outside of the cylinder 1 into the cylinder 1 along the through hole 11 a, passes through the partition wall 14, and is led out of the cylinder 1. As shown in FIG. 2, the first region 101 for introducing the cooling pipe 51 is a partial region of the outer wall 10 of the cylinder 1, and the second region 102 for leading the cooling pipe 51 is the outer wall 10. This is a partial region opposite to the first region 101.

The cooling pipe 51 is formed in a straight line and is made of a metal material having antiseptic properties such as rust prevention. As the material of the cooling pipe 51, for example, SUS (Steel Use Stainless) or other alloys are used. As the refrigerant, water is typically used, but it may be oil or gas.
Moreover, as a material of the cylinder 1, iron alloys, such as cast iron, aluminum alloys, etc. are mentioned. Thus, even when a material having low antiseptic properties is used as the material of the cylinder 1, the cooling pipe 51 has antiseptic properties, so that the cylinder 1 can be prevented from corroding.

  As shown in FIG. 1, the inner diameter of the through hole 11 a is formed close to the outer diameter of the cooling pipe 51. It is desirable that the gap between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11a be as narrow as possible.

  As shown in FIG. 2, sealing members 52 are provided between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11 a and at both ends of the cooling pipe 51. The sealing member 52 is, for example, an O-ring. At both ends of the cooling pipe 51, grooves (not shown) (for example, O-ring mounting grooves) having shapes corresponding to the respective sealing members 52 are provided. The cooling pipe 51 in which the sealing member 52 is mounted in a groove (not shown) can be passed through the through hole 11a, and the space between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11a can be sealed with the sealing member 52.

  The cylinder 1 has a communication path 11b. The communication path 11b is provided, for example, in the third region 103, which is the bottom of the cylinder 1, and communicates from the outside of the cylinder 1 to the through hole 11a. A plurality of communication passages 11 b are formed in the outer wall 10 of the cylinder 1. Each communication path 11b is connected to the through hole 11a at a position between the sealing members 52 and 52 provided at both ends of the through hole 11a. As for the position connected to the through-hole 11a of each communicating path 11b, it is desirable to be the vicinity of the sealing member 52, respectively.

  Due to the presence of the communication passage 11b, a heat conductive filler (for example, silicon-based heat conductive grease) can be introduced into the through hole 11a. For example, after the cooling pipe 51 and the plurality of sealing members 52 are attached to the cylinder body 11, the thermally conductive filler is passed from the arbitrary communication path 11b to the through hole 11a in a state where the plurality of communication paths 11b are released. May be introduced. Here, the sealing member 52 prevents the heat conductive filler from flowing out at both ends of the through hole 11a in the axial direction.

  The thermally conductive filler is introduced by using, for example, a grease gun. When a thermally conductive filler is introduced between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11a through one communication passage 11b, air is released from the through hole 11a through the other communication passage 11b. Is made. By sealing the end portion of each communication passage 11b that opens to the outside of the cylinder 1 with a plug 53 (for example, a screw), heat is generated between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11a. The state filled with the conductive filler can be maintained.

  Here, the through-hole 11a of the cylinder 1 is provided on the gas compression side (in the present embodiment, the side close to the third region 103 that is the bottom portion with the rotary shaft 20 as a boundary) for the reason described later. ing. Therefore, the communication path 11b is provided on the gas compression side, in this case, on the bottom side of the cylinder 1, whereby the distance between the outer end of the communication path 11b and the through hole 11a can be shortened. That is, the flow path length of the communication path 11b can be shortened. Thereby, while being able to simplify the structure of the cylinder 1, filling of a filler can be made easy and the quantity of the filler filled can be decreased.

  The operation of the vacuum pump 100 configured as described above will be described.

  When the rotational driving force is applied from the driving source 40 and one of the rotating shafts 20 (driving side) rotates, the rotors 21, 22, 23 of the driving-side multistage rotor 2 in the pump chambers 31, 32, 33 are rotated. It rotates (see FIG. 1). The rotational driving force of the drive-side rotary shaft 20 is transmitted to the other (driven-side) rotary shaft 20 via the timing gears 24 and 24 in the gear housing 41. As a result, the rotors 21, 22, and 23 of the driven multistage rotor 2 rotate in the reverse direction in synchronization with the rotors 21, 22, and 23 of the drive side multistage rotor 2, respectively. By the rotation of the multistage rotors 2 and 2, a pumping action is performed in the pump chambers 31, 32, and 33, in which the gas sucked from the intake port 301 is compressed and moved so as to be discharged toward the exhaust port 302. Thereby, the pressure and temperature of gas rise in the exhaust side which discharges | emits gas of each pump chamber.

  In the pump chambers 31, 32, and 33, the intake port 301 side (upper Z-axis direction) is on the intake side and the exhaust port 302 side (Z-axis opposite to the intake port 301) in the cross-sectional shape viewed in the axial direction of the rotary shaft 20 The lower side is the exhaust side. The gas discharged from the exhaust side (lower side) of the first pump chamber 31 passes through the connection path 34 formed in the partition wall 14 and is sucked into the intake side (upper side) of the second pump chamber 32. Further, the gas discharged from the exhaust side of the second pump chamber 32 passes through the connection path 35 formed in the partition wall 15 and is sucked into the intake side of the third pump chamber 33.

  As described above, the vacuum pump 100 achieves low arrival by compressing the gas stepwise from the low pressure side pump chamber (first pump chamber 31) to the high pressure side pump chamber (third pump chamber 33). Exhaust can be performed up to pressure.

  On the other hand, due to the temperature rise of the gas in each pump chamber, the exhaust side and the high pressure side (the right side in the X-axis direction) are likely to be hot inside the cylinder 1. Moreover, since the partition walls 14 and 15 and the multistage rotor 2 located inside the cylinder 1 are far from the outer wall 10 and are in a vacuum heat insulating state, heat radiation and cooling via the outer wall 10 are difficult to be performed. For this reason, the partition walls 14 and 15 inside the cylinder 1 are also likely to be hot. Therefore, in order to operate the vacuum pump 100 under an appropriate temperature condition, the cylinder 1 is cooled by flowing a refrigerant through the cooling pipe 51 provided in the cylinder 1. When the coolant is passed through the cooling pipe 51, the area around the cooling pipe 51 in the cylinder 1 is cooled through the thermally conductive filler filled between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11 a. Is done.

  In the vacuum pump 100, the cooling pipe 51 is introduced into the cylinder 1 from the outside of the cylinder 1 and led out to the outside of the cylinder 1 through the partition wall 14 inside the cylinder 1. The partition 14 inside the cylinder 1 can be cooled. The heat source of the cylinder 1 is in the pump chambers 31, 32, and 33 where compression heat is generated. For this reason, the partition walls 14 and 15 that partition the pump chambers 31, 32, and 33 are close to the heat source and are likely to have a high temperature. By installing the cooling pipe 51 in such a part, the vacuum pump 100 can be cooled from the inside near the heat source, and heat can be efficiently removed.

  In particular, in the case of the multistage vacuum pump according to the present embodiment, the gas compression side in each pump chamber 31, 32, 33, that is, the lower side from the rotary shaft 20 in FIG. Compared to the gas suction side in the chambers 31, 32, and 33), the temperature is higher. In the present embodiment, the cooling pipe 51 is arranged on the compression side where the temperature becomes higher with the rotary shaft 20 in the cylinder 1 as a boundary, thereby improving the cooling efficiency and the gas compression efficiency.

  For example, when a cooling flow path is formed directly in the cylinder partition wall to flow the refrigerant, the inside of the pump can be cooled directly, but the cylinder flow path is formed depending on the nature of the refrigerant. There is a risk of causing corrosion such as rust on the surface. On the other hand, according to the present embodiment, the flow path for cooling the inside of the cylinder 1 is formed in the cooling pipe 51, which is a separate member from the cylinder 1, so regardless of the nature of the refrigerant and the material of the cylinder 1. The risk of causing corrosion in the cylinder 1 can be avoided. Further, since the refrigerant flow path is not formed in the cylinder 1, the structure of the cylinder is not complicated, and the manufacture of the cylinder 1 is facilitated.

  Further, since the cooling pipe 51 is provided so as to penetrate the inside of the cylinder 1 linearly, the manufacturing of the cooling pipe 51 is easy, and the cooling pipe 51 can be installed by forming a through hole 11a in the cylinder 1. It becomes easy. Further, since it is not necessary to provide a gas flow path in the outer periphery of the pump in order to cool the gas, the vacuum pump 100 can be reduced in size, leading to space saving when the vacuum pump 100 is installed.

  Also, as the material of the cooling pipe 51, rust or antiseptic metal material such as SUS is used as described above, and therefore, the cooling pipe 51 is made use of the good thermal conductivity of the metal material during cooling. It can also prevent corrosion of itself.

  Note that if the cooling pipe 51 is simply passed through the through-hole 11a formed in the cylinder 1, if a gap is formed between the outer surface of the cooling pipe 51 and the inner surface of the through-hole 11a, air insulation prevents the cylinder 1 from It is conceivable that the efficiency of heat conduction to the cooling pipe 51 is reduced. Here, by providing the communication passage 11b and the sealing member 52 at both ends of the through hole 11a of the cylinder 1, a thermally conductive filler is provided between the outer surface of the cooling pipe 51 and the inner surface of the through hole 11a. Since it can be filled, air insulation can be prevented and thermal conductivity can be improved.

[Second Embodiment]
FIG. 4 is a schematic cross-sectional view showing a vacuum pump according to the second embodiment of the present invention. 5 is a cross-sectional view taken along line BB in FIG.
In the following description, the same members, functions, and the like included in the vacuum pump 100 according to the embodiment shown in FIG. 1 and the like will be simplified or omitted, and different points will be mainly described.

  As shown in FIG. 5, in the cylinder body 11 of the vacuum pump 120 according to the present embodiment, through holes 11c communicating from both sides in the Y-axis direction of the cylinder 1 to the connection path 35 (internal space 30) are formed coaxially. Has been. Each through hole 11 c is formed on both sides of the connection path 35 so as to penetrate the partition wall 15 and the outer wall 10 formed continuously to the partition wall 15.

  The cylinder body 11 is provided with a cooling pipe 51 as in the first embodiment. Moreover, the cooling pipe 61 is inserted and provided in both the above-mentioned through-holes 11c. As shown in FIG. 4, the cooling pipe 61 is provided in parallel with the cooling pipe 51, and a part of the outer surface of the cooling pipe 61 is exposed to the connection path 35. The cooling pipe 61 has substantially the same configuration as the cooling pipe 51. As shown in FIG. 5, sealing members 52 are provided between the outer surface of the cooling pipe 61 and the inner surface of the through hole 11 c and at both ends of the cooling pipe 61. The gap between the outer surface of the cooling pipe 61 and the inner surface of the through hole 11 c is sealed by the sealing member 52 at the end on the outer wall 10 side of the through hole 11 c communicating with the connection path 35. Therefore, the internal space 30 of the cylinder 1 can be kept airtight.

  As described above, the cooling pipe 61 may be provided so as to pass through the connection path 35 formed in the partition wall 15. Thereby, the high-temperature gas which distribute | circulates the connection path 35 can be directly cooled through the cooling pipe inside the cylinder 1, ie, near the heat source, particularly on the gas compression side.

[Third embodiment]
FIG. 6 is a schematic cross-sectional view showing a vacuum pump according to the third embodiment of the present invention. The cylinder body 11 of the vacuum pump 140 is provided with a sealing member 52 between the outer surface of the cooling pipe 61 and the inner surface of the through hole 11c and at both ends of each through hole 11c. In addition, a communication passage 11 b communicating from the outside of the cylinder 1 to the through hole 11 c is formed between the sealing members 52 on both sides and in the vicinity of each sealing member 52. Thereby, between the outer surface of the cooling pipe 61 and the inner surface of the through-hole 11c, a thermally conductive filler can be filled through the communication path 11b as in the first embodiment. Thus, as in the second embodiment, even when the cooling pipe 61 passes through the internal space 30 of the cylinder 1, heat conduction is performed between the outer surface of the cooling pipe 61 and the inner surface of the through hole 11c. The efficiency of cooling the partition wall 15 may be increased by filling the filler. Therefore, it is possible to directly cool the gas inside the cylinder 1 using the cooling pipe 61 and simultaneously cool the partition wall 15 inside the cylinder 1.

[Other embodiments]
The embodiment according to the present invention is not limited to the embodiment described above, and other various embodiments are realized.

  In the embodiment shown in FIG. 4, the cylinder 1 is provided with the cooling pipe 51 and the cooling pipe 61, but only the cooling pipe 61 may be provided. Further, the cooling pipe may be provided at any position of the cylinder as long as it passes through at least the partition wall, and may pass through the inside of the cylinder in any direction. For example, through holes may be formed in the partition walls of the first cover 12, the second cover 13, and the cylinder body 11, and the cooling pipe may be passed in a direction parallel to the rotation shaft 20.

  In the above embodiment, the material of the cooling pipe 51 is a metal material having antiseptic properties. However, even if the cooling pipe is formed of other materials, it is possible to prevent the cylinder 1 from being corroded. In addition, for example, by forming the cooling pipe with a metal material and performing rust prevention processing such as plating on the inner surface of the cooling pipe, corrosion of the cooling pipe itself can be prevented, and the same effect as the above embodiment can be obtained. it can.

  In the above embodiment, a three-stage Roots pump including a cylinder 1 having three pump chambers and a pair of multistage rotors 2 is illustrated as a vacuum pump. However, any configuration of the above embodiment may be applied to any form of vacuum pump as long as it is a multistage pump having a plurality of pump chambers. The number of pump chambers in which gas is compressed is not limited to three stages, and may be any number as long as it is two or more stages. The widths of the pump chambers and the rotor in the axial direction of the rotating shaft 20 may be the same among the plurality of pump chambers or may be different. The configuration outside the cylinder 1 such as the drive source 40 may be arranged on the high pressure side or on the low pressure side.

  For example, a saddle type rotor or a five-leaf type root type rotor may be employed instead of the three-leaf type root type rotor exemplified in the above embodiment. Moreover, in the said embodiment, although the form applied to a Roots pump was shown, it is not restricted to this, You may apply to a claw pump, or it applies to the vane pump provided with one vane rotor in each pump chamber. May be.

DESCRIPTION OF SYMBOLS 1 ... Cylinder 10 ... Outer wall 11 ... Cylinder main body 11a, 11c ... Through-hole 11b ... Communication path 14, 15 ... Partition 20 ... Rotating shaft 21, 22, 23 ... Rotor 30 ... Internal space 31 ... 1st pump chamber 32 ... 1st 2 pump chambers 33 ... third pump chamber 51, 61 ... cooling pipe 52 ... sealing member 100, 120, 140 ... vacuum pump 101 ... first region 102 ... second region 103 ... third region

Claims (10)

A rotation axis;
A plurality of rotors arranged along the rotation axis and attached to the rotation axis;
A cylinder that includes an outer wall, a plurality of pump chambers that respectively accommodate the plurality of rotors, and a partition that partitions the plurality of pump chambers, and rotatably supports the rotating shaft;
It is introduced into the cylinder from the outside of the cylinder through the first region of the outer wall, passes through at least the partition, and passes through the second region of the outer wall on the opposite side of the first region to the outside. A vacuum pump comprising a derived cooling pipe. The vacuum pump according to claim 1,
The cooling pipe is a linear vacuum pump. The vacuum pump according to claim 1 or 2,
The cylinder has a through hole formed in the first region, the partition wall, and the second region, through which the cooling pipe passes. The vacuum pump according to claim 3,
A vacuum pump further comprising a sealing member provided between an outer surface of the cooling pipe and an inner surface of the through hole. The vacuum pump according to claim 4,
The cylinder has a communication path communicating from the outside to the through hole. The vacuum pump according to claim 5,
The communication path is provided in a third region of the outer wall that is different from the first and second regions. The vacuum pump according to claim 5 or 6,
The cylinder has a plurality of communication passages. A vacuum pump according to any one of claims 5 to 7,
A vacuum pump further comprising a plug for sealing the communication path. A vacuum pump according to any one of claims 1 to 8,
The cooling pipe is provided so as to pass through an internal space including the plurality of pump chambers of the cylinder. A vacuum pump according to any one of claims 1 to 9,
The cooling pipe is formed of a metal material having antiseptic properties.

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